title: Decays of doubly charmed meson molecules

abstract:
  Several observed states close to the $D\bar{D}^*$ and
$D^*_{(s)}\bar{D}^*_{(s)}$ thresholds, as the X(3872) and some XYZ particles
can be described in terms of a two-meson molecule. Furthermore, doubly charmed
states are also predicted. These new states are near the $D^*D^*$ and
$D^*D^*_s$ thresholds, % Therefore, if the previous XYZ are molecules, then,
there should be doubly charmed mesons with $J^P=1^+$ around the $D^*D^*$
threshold.
  %For this reason, it is important to evaluate observables related to them.
Because of the spin$=1$, they do not decay into $DD$. In this article we
compute decays to $DD^*$ and radiative decays of doubly charmed meson molecules
into $DD_{(s)}\gamma$. and have spin-parity $J^P=1^+$. Their natural decay
modes are $D_{(s)}D^*$, $DD_{(s)}\pi$ and $DD_{(s)}\gamma$ and
$D^*D_{(s)}\gamma$. We evaluate the widths of these states, named here as
$R_{cc}(3970)$ and $S_{cc}(4100)$, and obtain 44 MeV for the non-strangeness,
and 24 MeV for the doubly charm-strange state. Essentially, the decay modes are
$DD_{(s)}\pi$ and $DD_{(s)}\gamma$, being the $D\pi$ and $D\gamma$ emitted by
one of the $D^*$ meson which forms the molecule.


title: Critical ingredients of supernova Ia radiative-transfer modeling

abstract:
  We explore the physics of SN Ia light curves and spectra using the 1-D
non-LTE time-dependent radiative-transfer code CMFGEN. Rather than adjusting
ejecta properties to match observations, we select as input one "standard" 1-D
Chandrasekhar-mass delayed-detonation hydrodynamical model, and then explore
the sensitivity of radiation and gas properties on radiative-transfer modeling
assumptions. The correct computation of SN Ia radiation is not exclusively a
solution to an "opacity problem", characterized by the treatment of a large
number of lines. It is also key to treat important atomic processes
consistently. Besides handling line blanketing in non-LTE, we show that
including forbidden line transitions of metals is increasingly important for
the temperature and ionization of the gas beyond maximum light. Non-thermal
ionization and excitation are also critical since they affect the color
evolution and the Delta-M15 of our model. While impacting little the bolometric
luminosity, a more complete treatment of decay routes leads to enhanced line
blanketing, e.g., associated with 48Ti in the U and B bands. Overall, we find
that SN Ia radiation properties are influenced in a complicated way by the
atomic data we employ, so that obtaining converged results is a challenge. We
nonetheless obtain a good match to the golden standard type Ia SN 2005cf in the
optical and near-IR, from 5 to 60d after explosion, suggesting that assuming
spherical symmetry is not detrimental to SN Ia radiative-transfer modeling at
these times. Multi-D effects no doubt matter, but they are perhaps less
important than accurately treating non-LTE processes [abridged].


title:
Interface-induced Topological Insulator Transition in GaAs/Ge/GaAs
  Quantum Wells

abstract:
  We demonstrate theoretically that interface engineering can drive Germanium,
one of the most commonly-used semiconductors, into topological insulating
phase. Utilizing giant electric fields generated by charge accumulation at
GaAs/Ge/GaAs opposite semiconductor interfaces and band folding, the new design
can reduce the sizable gap in Ge and induce large spin-orbit interaction, which
lead to a topological insulator transition. Our work provides a new method on
realizing TI in commonly-used semiconductors and suggests a promising approach
to integrate it in well developed semiconductor electronic devices.


title:
Thermal Fluctuation Statistics in a Molecular Motor Described by a
  Multidimensional Master Equation

abstract:
  We present a theoretical investigation of thermal fluctuation statistics in a
molecular motor. Energy transfer in the motor is described using a
multidimensional discrete master equation with nearest-neighbor hopping. In
this theory, energy transfer leads to statistical correlations between thermal
fluctuations in different degrees of freedom. For long times, the energy
transfer is a multivariate diffusion process with a constant drift and
diffusion. The fluctuations and drift align in the strong-coupling limit
enabling a one-dimensional description along the coupled coordinate. We derive
formal expressions for the probability distribution and simulate single
trajectories of the system in the near and far from equilibrium limits both for
strong and weak coupling. Our results show that the hopping statistics provide
an opportunity to distinguish different operating regimes.


title: Microwave Signature of Relativistic Positrons in Solar Flares

abstract:
  Relativistic antiparticles can be created in high-energy nuclear
interactions; thus, detection of antiparticles in an astrophysical source can
tell us something remarkable about the underlying high-energy processes and
nuclear interactions. However, once created, the antiparticles remain a minor
fraction of their conjugant normal particles, so the detection of the
antiparticles represents a big science challenge. To address this challenge we
employ imaging and polarimetry of microwave radiation produced as the positrons
gyrate in the ambient magnetic field. The key property of the radiation used in
this method is that the oppositely charged particles, electrons and positrons,
produce radiation with opposite helicity, easily distinguishable by currently
operating radio facilities. Analysis of available spatially resolved microwave
data augmented by independent magnetic field measurements allows us to remotely
detect the relativistic positron component in several solar flares.


title: Respondent-Driven Sampling in Online Social Networks

abstract:
  Respondent-driven sampling (RDS) is a commonly used method for acquiring data
on hidden communities, i.e., those that lack unbiased sampling frames or face
social stigmas that make their mem- bers unwilling to identify themselves.
Obtaining accurate statistical data about such communities is important
because, for instance, they often have different health burdens from the
greater population, and without good statistics it is hard and expensive to
effectively reach them for pre- vention or treatment interventions. Online
social networks (OSN) have the potential to transform RDS for the better. We
present a new RDS recruitment protocol for (OSNs) and show via simulation that
it out- performs the standard RDS protocol in terms of sampling accuracy and
approaches the accuracy of Markov chain Monte Carlo random walks.


title:
Control of Propagating Spin Waves via Spin Transfer Torque in a Metallic
  Bilayer Waveguide

abstract:
  We investigate the effect of a direct current on propagating spin waves in a
CoFeB/Ta bilayer structure. Using the micro-Brillouin light scattering
technique, we observe that the spin wave amplitude may be attenuated or
amplified depending on the direction of the current and the applied magnetic
field. Our work suggests an effective approach for electrically controlling the
propagation of spin waves in a magnetic waveguide and may be useful in a number
of applications such as phase locked nano-oscillators and hybrid information
processing devices.


title: Instantons on the exceptional holonomy manifolds of Bryant and Salamon

abstract:
  We give a construction of $G_2$ and $Spin(7)$ instantons on exceptional
holonomy manifolds constructed by Bryant and Salamon, by using an ansatz of
spherical symmetry coming from the manifolds being the total spaces of rank-4
vector bundles. In the $G_2$ case, we show that, in the asymptotically conical
model, the connections are asymptotic to Hermitian Yang-Mills connections on
the nearly K\"ahler $S^3\times S^3$.


title: Conditions for degradability of tripartite quantum states

abstract:
  Alice, Bob, and Eve share a pure quantum state. We introduce the notion of
state degradability by asking whether the joint density of Alice and Eve can be
transformed to the joint density of Alice and Bob by processing Eve's part
through a quantum channel, in order words, degrading Eve. We prove necessary
and sufficient conditions for state degradability and provide an efficient
method to quickly rule out degradability for a given state. The problem of
determining degradability of states is different from that of quantum channels,
although the notion is similar. One application of state degradability is that
it can be used to test channel degradability. In particular, the degradability
of the output state of a channel obtained from the maximally entangled input
state gives information about the degradability of the channel.


title: Photon blockade in quadratically coupled optomechanical systems

abstract:
  We study the steady-state photon statistics of a quadratically coupled
optomechanical cavity, which is weakly driven by a monochromatic laser field.
We examine the photon blockade by evaluating the second-order correlation
function of the cavity photons. By restricting the system within the zero-,
one-, and two-photon subspace, we obtain an approximate analytical expression
for the correlation function. We also numerically investigate the correlation
function by solving the quantum master equation including both optical and
mechanical dissipations. The results show that, in the deep-resolved-sideband
and single-photon strong-coupling regimes, the single-photon resonant driving
will induce a photon blockade, which is limited by the thermal noise of the
mechanical environment.


title: A Remarkable Definite Integral

abstract:
  An integral formula is developed which applies to an essentially arbitrary
function. An application is made to the Riemann zeta function.


title:
The Legacy of Hideki Yukawa, Sin-itiro Tomonaga, and Shoichi Sakata:
  Some Aspects from their Archives

abstract:
  Hideki Yukawa, Sin-itiro Tomonaga and Shoichi Sakata pioneered nuclear and
particle physics and left enduring legacies. Their friendly collaboration and
severe competition laid the foundation to bring up the active postwar
generation of nuclear and particle physicists in Japan. In this presentation we
illustrate milestones of nuclear and particle physics in Japan from 1930's to
mid-1940's which have been clarified in Yukawa Hall Archival Library, Tomonaga
Memorial Room and Sakata Memorial Archival Library.


title:
Measuring digital crime investigation capacity to guide international
  crime prevention strategies

abstract:
  This work proposes a method for the measurement of a country's digital
investigation capacity and saturation for the assessment of future capacity
expansion. The focus is on external, or international, partners being a factor
that could negatively affect the return on investment when attempting to expand
investigation capacity nationally. This work concludes with the argument that
when dealing with digital crime, target international partners should be a
consideration in expansion, and could potentially be a bottleneck of
investigation requests.


title:
The Higgs boson inclusive decay channels $H \to b\bar{b}$ and $H \to gg$
  up to four-loop level

abstract:
  The principle of maximum conformality (PMC) has been suggested to eliminate
the renormalization scheme and renormalization scale uncertainties, which are
unavoidable for the conventional scale setting and are usually important errors
for theoretical estimations. In this paper, by applying PMC scale setting, we
analyze two important inclusive Standard Model Higgs decay channels,
$H\rightarrow b\bar{b}$ and $H\rightarrow gg$, up to four-loop and three-loop
levels accordingly. After PMC scale setting, it is found that the conventional
scale uncertainty for these two channels can be eliminated to a high degree.
There is small residual initial scale dependence for the Higgs decay widths due
to unknown higher-order $\{\beta_i\}$-terms. Up to four-loop level, we obtain
$\Gamma(H\rightarrow b\bar{b}) = 2.389\pm0.073 \pm0.041$ MeV and up to
three-loop level, we obtain $\Gamma(H\rightarrow gg) = 0.373\pm0.030$ MeV,
where the first error is caused by varying $M_H=126\pm4$ GeV and the second
error for $H\to b\bar{b}$ is caused by varying the $\overline{\rm MS}$-running
mass $m_b(m_b)=4.18\pm0.03$ GeV. Taking $H\to b\bar{b}$ as an example, we
present a comparison of three BLM-based scale setting approaches, e.g. the
PMC-I approach based on the PMC-BLM correspondence, the $R_\delta$-scheme and
the seBLM approach, all of which are designed to provide effective ways to
identify non-conformal $\{\beta_i\}$-series at each perturbative order. At
four-loop level, all those approaches lead to good pQCD convergence, they have
almost the same pQCD series, and their predictions are almost independent on
the initial renormalization scale. In this sense, those approaches are
equivalent to each other.


title:
Helicoidal magnetic ordering in crystals: exact periodic solutions of
  equations of state with fourth-order anisotropy

abstract:
  In this paper we obtain an exact periodic solution for the system of
equations of state corresponding to the spiral phase of crystalline ordering.
We used method of integral rational basis of invariants to construct an
inhomogeneous Landau potential. As a result the inhomogeneous Landau potential
takes account of anisotropic invariants consisting of OP components as well as
anisotropic invariants that comprise space derivatives of OP components. It is
demonstrated that it is taking into account the latter that leads to the exact
periodic solution for the system of equations of state that describes the
spiral phase. A phase diagram of states is built for active Lifshitz
representations at the second-order phase transition point. Analogy between
inhomogeneous states of A-phase and second-order superconductors in the
magnetic field is discussed. It is suggested to describe the vortex state in
the magnetic field as a deformation of the magnetic sublattice with
dislocations.


title: The Conley index, gauge theory, and triangulations

abstract:
  This is an expository paper about Seiberg-Witten Floer stable homotopy types.
We outline their construction, which is based on the Conley index and finite
dimensional approximation. We then describe several applications, including the
disproof of the high-dimensional triangulation conjecture.


title:
Partial differential equation about the prevalence of a chronic disease
  in the presence of duration dependency

abstract:
  The illness-death model of a chronic disease consists of the states 'Normal',
'Disease' and 'Death'. In general, the transition rates between the states
depend on three time scales: calendar time, age and duration of the chronic
disease. Previous works have shown that the age-specific prevalence of the
chronic disease can be described by differential equations if the duration is
negligible. This article derives a partial differential equation (PDE) in the
presence of duration dependency. As an important application, the PDE allows
the calculation of the age-specific incidence from cross-sectional surveys.


title: Incremental Grid-like Layout Using Soft and Hard Constraints

abstract:
  We explore various techniques to incorporate grid-like layout conventions
into a force-directed, constraint-based graph layout framework. In doing so we
are able to provide high-quality layout---with predominantly axis-aligned
edges---that is more flexible than previous grid-like layout methods and which
can capture layout conventions in notations such as SBGN (Systems Biology
Graphical Notation). Furthermore, the layout is easily able to respect
user-defined constraints and adapt to interaction in online systems and diagram
editors such as Dunnart.


title:
Continuation of the zero set for discretely self-similar solutions to
  the Euler equations

abstract:
  We are concerned on the study of the unique continuation type property for
the 3D incompressible Euler equations in the self-similar type form. Discretely
self-similar solution is a generalized notion of the self-similar solution,
which is equivalent to a time periodic solution of the time dependent
self-similar Euler equations. We prove the unique continuation type theorem for
the discretely self-similar solutions to the Euler equations in $\Bbb R^3$.
More specifically, we suppose there exists an open set $G\subset \Bbb R^3$
containing the origin such that the velocity field $V\in C_s^1C^{2}_y (\Bbb
R^{3+1})$ vanishes on $G\times (0, S_0)$, where $S_0 > 0$ is the temporal
period for $V(y,s)$. Then, we show $V(y,s)=0$ for all $(y,s)\in \Bbb R^{3+1}$.
Similar property also holds for the inviscid magnetohydrodynamic system


title:
Fast Convergence of Stochastic Gradient Descent under a Strong Growth
  Condition

abstract:
  We consider optimizing a function smooth convex function $f$ that is the
average of a set of differentiable functions $f_i$, under the assumption
considered by Solodov [1998] and Tseng [1998] that the norm of each gradient
$f_i'$ is bounded by a linear function of the norm of the average gradient
$f'$. We show that under these assumptions the basic stochastic gradient method
with a sufficiently-small constant step-size has an $O(1/k)$ convergence rate,
and has a linear convergence rate if $g$ is strongly-convex.


title: Analyticity in spaces of convergent power series and applications

abstract:
  We study the analytic structure of the space of germs of an analytic function
at the origin of \ww C^{\times m} , namely the space \germ{\mathbf{z}} where
\mathbf{z}=\left(z\_{1},\cdots,z\_{m}\right) , equipped with a convenient
locally convex topology. We are particularly interested in studying the
properties of analytic sets of \germ{\mathbf{z}} as defined by the vanishing
locus of analytic maps. While we notice that \germ{\mathbf{z}} is not Baire we
also prove it enjoys the analytic Baire property: the countable union of proper
analytic sets of \germ{\mathbf{z}} has empty interior. This property underlies
a quite natural notion of a generic property of \germ{\mathbf{z}} , for which
we prove some dynamics-related theorems. We also initiate a program to tackle
the task of characterizing glocal objects in some situations.


title:
Smoothly slice boundary links whose derivative links have nonvanishing
  Milnor invariants

abstract:
  We give an example of a 3-component smoothly slice boundary link, each of
whose components has a genus one Seifert surface, such that any metaboliser of
the boundary link Seifert form is represented by 3 curves on the Seifert
surfaces that form a link with nonvanishing Milnor triple linking number. We
also give a generalisation to m-component links and higher Milnor invariants.
We prove that our examples are ribbon and that all ribbon links are boundary
slice.


title: Special Bent and Near-bent Functions

abstract:
  Starting from special near-bent functions in dimension 2t-1 we construct bent
functions in dimension 2t having a specific derivative. We deduce new famillies
of bent functions


title:
Weierstrass cycles and tautological rings in various moduli spaces of
  algebraic curves

abstract:
  We analyze Weierstrass cycles and tautological rings in moduli space of
smooth algebraic curves and in moduli spaces of integral algebraic curves with
embedded disks with special attention to moduli spaces of curves having genus
$\leq 6$. In particular, we show that our general formula gives a good estimate
for the dimension of Weierstrass cycles for lower genera.


title:
Detection of an ultra-bright submillimeter galaxy behind the Small
  Magellanic Cloud

abstract:
  We report the discovery of a new ultra-bright submillimeter galaxy (SMG)
behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3+-8.4
mJy point source (MM J01071-7302, hereafter MMJ0107) in the 1.1 mm continuum
survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in
the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24 {\mu}m, all IRAC bands,
Wide-field Infrared Survey Explorer, and near-infrared (J, H, KS). We find an
optical (U, B, V) source, which might be the lensing object, at a distance of
1.4 arcsec from near-infrared and IRAC sources. Photometric redshift estimates
for the SMG using representative spectral energy distribution templates show
the redshifts of 1.4-3.9. We estimate total far-infrared luminosity of
(0.3-2.2)x10^14 {\mu}^-1 L_sun and a star formation rate of 5600-39, 000
{\mu}^-1 M_sun yr^-1, where {\mu} is the gravitational magnification factor.
This apparent extreme star formation activity is likely explained by a highly
magnified gravitational lens system.


title: Quench dynamics of a strongly interacting resonant Bose gas

abstract:
  We explore the dynamics of a Bose gas following its quench to a strongly
interacting regime near a Feshbach resonance. Within a self-consistent
Bogoliubov analysis we find that after the initial condensate-quasiparticle
Rabi oscillations, at long time scales the gas is characterized by a
nonequilibrium steady-state momentum distribution function, with depletion,
condensate density and contact that deviate strongly from their corresponding
equilibrium values. These are in a qualitative agreement with recent
experiments on Rb85 by Makotyn, et al. Our analysis also suggests that for
sufficiently deep quenches close to the resonance the nonequilibrium state
undergoes a phase transition to a fully depleted state, characterized by a
vanishing condensate density.


title: Higher genus quasimap wall-crossing for semi-positive targets

abstract:
  In previous work (arXiv:1304.7056) we have conjectured wall-crossing formulas
for genus zero quasimap invariants of GIT quotients and proved them via
localization in many cases. We extend these formulas to higher genus when the
target is semi-positive, and prove them for semi-positive toric varieties, in
particular for toric local Calabi-Yau targets. The proof also applies to local
Calabi-Yau's associated to some non-abelian quotients.


title:
String-Averaging Projected Subgradient Methods for Constrained
  Minimization

abstract:
  We consider constrained minimization problems and propose to replace the
projection onto the entire feasible region, required in the Projected
Subgradient Method (PSM), by projections onto the individual sets whose
intersection forms the entire feasible region. Specifically, we propose to
perform such projections onto the individual sets in an algorithmic regime of a
feasibility-seeking iterative projection method. For this purpose we use the
recently developed family of Dynamic String-Averaging Projection (DSAP) methods
wherein iteration-index-dependent variable strings and variable weights are
permitted. This gives rise to an algorithmic scheme that generalizes, from the
algorithmic structural point of view, earlier work of Helou Neto and De Pierro,
of Nedi\'c, of Nurminski, and of Ram et al.


title:
Backward stochastic differential equations with stopping time as time
  horizon

abstract:
  In this paper, we introduce a new method for study on backward stochastic
differential equations with stopping time as time horizon. And using this, we
show that some results on backward stochastic differential equations with
constant time horizon are generalized to the case of random time horizon.


title: Infinitesimal Rigidity of Symmetric Frameworks

abstract:
  We propose new symmetry-adapted rigidity matrices to analyze the
infinitesimal rigidity of arbitrary-dimensional bar-joint frameworks with
Abelian point group symmetries. These matrices define new symmetry-adapted
rigidity matroids on group-labeled quotient graphs. Using these new tools, we
establish combinatorial characterizations of infinitesimally rigid
two-dimensional bar-joint frameworks whose joints are positioned as generic as
possible subject to the symmetry constraints imposed by a reflection, a
half-turn or a three-fold rotation in the plane. For bar-joint frameworks which
are generic with respect to any other cyclic point group in the plane, we
provide a number of necessary conditions for infinitesimal rigidity.


title: Critical Casimir forces along the iso-fields

abstract:
  Using quasi-exact numerical density-matrix renormalization-group techniques
we calculate the critical Casimir force for a two-dimensional (2D) Ising strip
with equal strong surface fields, along the thermodynamic paths corresponding
to the fixed nonzero bulk field h<>0. Using the Derjaguin approximation we also
determine the critical Casimir force and its potential for two discs. We find
that varying the temperature along the iso-fields lying between the bulk
coexistence and the capillary condensation critical point leads to a dramatic
increase of the critical Casimir interactions with a qualitatively different
functional dependence on the temperature than along h=0. These findings might
be of relevance for biomembranes, whose heterogeneity is recently interpreted
as being connected with a critical behavior belonging to the 2D Ising
universality class.


title:
H5MD: a structured, efficient, and portable file format for molecular
  data

abstract:
  We propose a new file format named "H5MD" for storing molecular simulation
data, such as trajectories of particle positions and velocities, along with
thermodynamic observables that are monitored during the course of the
simulation. H5MD files are HDF5 (Hierarchical Data Format) files with a
specific hierarchy and naming scheme. Thus, H5MD inherits many benefits of
HDF5, e.g., structured layout of multi-dimensional datasets, data compression,
fast and parallel I/O, and portability across many programming languages and
hardware platforms. H5MD files are self-contained and foster the
reproducibility of scientific data and the interchange of data between
researchers using different simulation programs and analysis software. In
addition, the H5MD specification can serve for other kinds of data (e.g.
experimental data) and is extensible to supplemental data, or may be part of an
enclosing file structure.


title:
Proton irradiation robustness of dielectric mirrors for high-finesse
  Fabry-P\'erot resonators in the near-infrared spectral range

abstract:
  We demonstrate that a proton irradiation with fluences of
$3.6\times10^{10}$/cm$^{2}$ at low energy ($<$ 36 MeV) and $1.46 \times
10^{10}$/cm$^{2}$ at high energy (40 MeV and 90 MeV combined) on the dielectric
mirrors of Fabry-P\'erot cavities with a finesse of about 700 000 causes less
than 5% change in the finesse. Furthermore, no influence on the coupling
efficiency to the cavities was observed, the efficiency being approximately
70%. The irradiation was carried out with a spectrum approximating the proton
energy spectrum of a highly elliptic Earth orbit with duration of 5 years,
proposed for the Space-Time Explorer and Quantum Equivalence Space Test
(STE-QUEST) mission [\url{http://sci.esa.int/ste-quest/}].


title: Collecting Coupons with Random Initial Stake

abstract:
  Motivated by a problem in the theory of randomized search heuristics, we give
a very precise analysis for the coupon collector problem where the collector
starts with a random set of coupons (chosen uniformly from all sets).
  We show that the expected number of rounds until we have a coupon of each
type is $nH_{n/2} - 1/2 \pm o(1)$, where $H_{n/2}$ denotes the $(n/2)$th
harmonic number when $n$ is even, and $H_{n/2}:= (1/2) H_{\lfloor n/2 \rfloor}
+ (1/2) H_{\lceil n/2 \rceil}$ when $n$ is odd. Consequently, the coupon
collector with random initial stake is by half a round faster than the one
starting with exactly $n/2$ coupons (apart from additive $o(1)$ terms).
  This result implies that classic simple heuristic called \emph{randomized
local search} needs an expected number of $nH_{n/2} - 1/2 \pm o(1)$ iterations
to find the optimum of any monotonic function defined on bit-strings of length
$n$.


title:
A possible realization of multi-channel Kondo model in a system of
  magnetic chains

abstract:
  We discuss a possible realization of overscreened multi-channel Kondo model
in quasi-one-dimensional magnets.


title: Galactic Stellar Populations in the Era of SDSS and Other Large Surveys

abstract:
  Studies of stellar populations, understood to mean collections of stars with
common spatial, kinematic, chemical, and/or age distributions, have been
reinvigorated during the last decade by the advent of large-area sky surveys
such as SDSS, 2MASS, RAVE, and others. We review recent analyses of these data
that, together with theoretical and modeling advances, are revolutionizing our
understanding of the nature of the Milky Way, and galaxy formation and
evolution in general. The formation of galaxies like the Milky Way was long
thought to be a steady process leading to a smooth distribution of stars.
However, the abundance of substructure in the multi-dimensional space of
various observables, such as position, kinematics, and metallicity, is by now
proven beyond doubt, and demonstrates the importance of mergers in the growth
of galaxies. Unlike smooth models that involve simple components, the new data
reviewed here clearly show many irregular structures, such as the Sagittarius
dwarf tidal stream and the Virgo and Pisces overdensities in the halo, and the
Monoceros stream closer to the Galactic plane. These recent developments have
made it clear that the Milky Way is a complex and dynamical structure, one that
is still being shaped by the merging of neighboring smaller galaxies. We also
briefly discuss the next generation of wide-field sky surveys, such as
SkyMapper, Pan-STARRS, Gaia and LSST, which will improve measurement precision
manyfold, and comprise billions of individual stars. The ultimate goal,
development of a coherent and detailed story of the assembly and evolutionary
history of the Milky Way and other large spirals like it, now appears well
within reach.


title: Efficient hedging in general Black-Scholes model

abstract:
  An investor faced with a contingent claim may eliminate risk by perfect
hedging, but as it is often quite expensive, he seeks partial hedging (quantile
hedging or efficient hedging) that requires less capital and reduces the risk.
Efficient hedging for European call option was considered in the standard
Black-Scholes model with constant drift and volatility coefficients. In this
paper we considered the efficient hedging for European call option in general
Black-Scholes model $dX_t=X_t(m(t)dt+\sigma (t)dw(t))$ with time-varying drift
and volatility coefficients and in fractional Black-Scholes model
$dX_t=X_t(\sigma B_H(t)+mdt)$ with constant coefficients.


title: GNCGCP - Graduated NonConvexity and Graduated Concavity Procedure

abstract:
  In this paper we propose the Graduated NonConvexity and Graduated Concavity
Procedure (GNCGCP) as a general optimization framework to approximately solve
the combinatorial optimization problems on the set of partial permutation
matrices. GNCGCP comprises two sub-procedures, graduated nonconvexity (GNC)
which realizes a convex relaxation and graduated concavity (GC) which realizes
a concave relaxation. It is proved that GNCGCP realizes exactly a type of
convex-concave relaxation procedure (CCRP), but with a much simpler formulation
without needing convex or concave relaxation in an explicit way. Actually,
GNCGCP involves only the gradient of the objective function and is therefore
very easy to use in practical applications. Two typical NP-hard problems,
(sub)graph matching and quadratic assignment problem (QAP), are employed to
demonstrate its simplicity and state-of-the-art performance.


title:
Strain and composition dependence of the orbital polarization in
  nickelate superlattices

abstract:
  A combined analysis of x-ray absorption and resonant reflectivity data was
used to obtain the orbital polarization profiles of superlattices composed of
four-unit-cell-thick layers of metallic LaNiO3 and layers of insulating RXO3
(R=La, Gd, Dy and X=Al, Ga, Sc), grown on substrates that impose either
compressive or tensile strain. This superlattice geometry allowed us to partly
separate the influence of epitaxial strain from interfacial effects controlled
by the chemical composition of the insulating blocking layers. Our quantitative
analysis reveal orbital polarizations up to 25%. We further show that strain is
the most effective control parameter, whereas the influence of the chemical
composition of the blocking layers is comparatively small.


title: On the representation theory of partition (easy) quantum groups

abstract:
  Compact matrix quantum groups are strongly determined by their intertwiner
spaces, due to a result by S.L. Woronowicz. In the case of easy quantum groups,
the intertwiner spaces are given by the combinatorics of partitions, see the
inital work of T. Banica and R. Speicher. The philosophy is that all quantum
algebraic properties of these objects should be visible in their combinatorial
data. We show that this is the case for their fusion rules (i.e. for their
representation theory). As a byproduct, we obtain a unified approach to the
fusion rules of the quantum permutation group $S_N^+$, the free orthogonal
quantum group $O_N^+$ as well as the hyperoctahedral quantum group $H_N^+$.


title: Geometric properties of generalized symmetric spaces

abstract:
  It is shown that four-dimensional generalized symmetric spaces can be
naturally equipped with some additional structures defined by means of their
curvature operators. As an application, those structures are used to
characterize generalized symmetric spaces.


title:
Minimum survival probabilities in a two-dimensional risk model perturbed
  by diffusion

abstract:
  In this paper we consider the finite time minimum survival probability and
ultimate minimum survival probability in a two ? dimensional risk modal
perturbed by diffusion Using some properties of the minimum survival
probability we obtain the equation of the finite time minimum survival
probability and ultimate minimum survival probability that they are satisfied
and, the explicit expressions for ultimate minimum survival probability are
given in a special case.


title:
Anomalous Frequency Trends in MoS2 Thin Films Attributed to Surface
  Effects

abstract:
  The layered dichalcogenide MoS2 has many unique physical properties in low
dimensions. Recent experimental Raman spectroscopies report an anomalous blue
shift of the in-plane E2g1 mode with decreasing thickness, a trend that is not
understood. Here, we combine experimental Raman scattering and theoretical
studies to clarify and explain this trend. Special attention is given to
understanding the surface effect on Raman frequencies by using a force
constants model based on first-principles calculations. Surface effects refer
to the larger Mo-S force constants at the surface of thin film MoS2, which
results from a loss of neighbours in adjacent MoS2 layers. Without surface
effects, the frequencies of both out-of-plane A1g and in-plane E2g1 modes
decrease with decreasing thickness. However, the E2g1 mode blue shifts while
the A1g mode red shifts once the surface effect is included, in agreement with
the experiment. Our results show that competition between the thickness effect
and the surface effect determines the mechanical properties of two-dimensional
MoS2, which we believe applies to other layered materials.


title:
Adaptive nonparametric estimation for L\'evy processes observed at low
  frequency

abstract:
  This article deals with adaptive nonparametric estimation for L\'evy
processes observed at low frequency. For general linear functionals of the
L\'evy measure, we construct kernel estimators, provide upper risk bounds and
derive rates of convergence under regularity assumptions. Our focus lies on the
adaptive choice of the bandwidth, using model selection techniques. We face
here a non-standard problem of model selection with unknown variance. A new
approach towards this problem is proposed, which also allows a straightforward
generalization to a classical density deconvolution framework.


title:
The Time Structure of Hadronic Showers in Imaging Calorimeters with
  Scintillator and RPC Readout

abstract:
  The intrinsic time structure of hadronic showers has been studied to evaluate
its influence on the timing capability and on the required integration time of
highly granular hadronic calorimeters in future collider experiments. The
experiments have been carried with systems of 15 detector cells, using both
scintillator tiles with SiPM readout and RPCs, read out with fast digitizers
and deep buffers. These were installed behind the CALICE scintillator -
Tungsten and RPC - Tungsten calorimeters as well as behind the CALICE
semi-digital RPC - Steel calorimeter during test beam periods at the CERN SPS.
We will discuss the technical aspects of these systems, and present results on
the measurement of the time structure of hadronic showers in steel and tungsten
calorimeters. These are compared to GEANT4 simulations, providing important
information for the validation and the improvement of the physics models. In
addition, a comparison of the observed time structure with scintillator and RPC
active elements will be presented, which provides insight into the differences
in sensitivity to certain aspects of hadronic showers depending on readout
technology.


title:
Reversal and tunability of the surface plasmon enhanced optical forces
  on a nanorod pair in the presence of a dielectric interlayer

abstract:
  We investigate numerically the modification of surface-plasmon assisted
optical force on a gold nanorod pair by incorporating dielectric interlayer.
The frequency dependent electromagnetic forces are obtained through
full-vectorial solution of Maxwell equations with a finite element solver. We
obtain the common and relative electromagnetic force experienced by the
nanorods with dielectric interlayers of different permittivity or thickness. In
particular, we demonstrate that the use of a liquid crystal interlayer can be
utilized as a dynamic tuning mechanism for the reversal of the direction of the
relative force.


title: Metastable states in Brownian energy landscape

abstract:
  Random walks and diffusions in symmetric random environment are known to
exhibit metastable behavior: they tend to stay for long times in wells of the
environment. For the case that the environment is a one-dimensional two-sided
standard Brownian motion, we study the process of depths of the consecutive
wells of increasing depth that the motion visits. When these depths are looked
in logarithmic scale, they form a stationary renewal cluster process. We give a
description of the structure of this process and derive from it the almost sure
limit behavior and the fluctuations of the empirical density of the process.


title:
Giant circular dichroism in individual carbon nanotubes induced by
  extrinsic chirality

abstract:
  Circular dichroism is widely used for characterizing organic and biological
materials, but measurements at a single molecule level are challenging because
differences in absorption for opposite helicities are small. Here we show that
extrinsic chirality can induce giant circular dichroism in individual carbon
nanotubes, with degree of polarization reaching 65%. The signal has a large
dependence on the incidence angle, consistent with the interpretation that
mirror symmetry breaking by the optical wave vector is responsible for the
effect. We propose that field-induced charge distribution results in an
efficient polarization conversion, giving rise to the giant dichroism. Our
results highlight the possibility of polarization manipulation at the nanoscale
for applications in integrated photonics and novel metamaterial designs.


title: Coding Methods in Computability Theory and Complexity Theory

abstract:
  A major part of computability theory focuses on the analysis of a few
structures of central importance. As a tool, the method of coding with
first-order formulas has been applied with great success. For instance, in the
c.e. Turing degrees, it has been used to determine the complexity of the
elementary theory, to provide restrictions on automorphisms, and even to obtain
definability results (work of Harrington, Nies, Shore, Slaman, and others).
  We describe how a similar program can be carried out for several other
structures, including the structure of c.e. many one degrees, the structure of
c.e. weak truth table degrees and the lattice of c.e. sets under inclusion. In
all cases we will obtain undecidability of, or even an interpretation of true
arithmetic in the theory of the structure. For the c.e. many one-degrees, we
also obtain definability results and restrictions on automorphisms.
  This work appeared first as the author's habilitation thesis at the
Universitaet Heidelberg, 1998.


title:
Optimal interface doping at La_2/3Sr_1/3MnO_3/SrTiO_3(001)
  heterojunctions for spintronic applications

abstract:
  We examine, by means of ab initio pseudopotential calculations,
La_2/3Sr_1/3MnO_3/SrTiO_3 (LSMO/STO) heterojunctions in which one unit layer of
La_(1-x)Sr_xMnO_3 (with 0<x<1) is inserted at the interface. The optimal
interlayer doping x for a robust interface ferromagnetism is investigated by
considering the energy differences between antiferromagnetic and ferromagnetic
alignment of the MnO_2-interface layer relative to bulk LSMO. The optimal
doping is found to be close to x=1/3, which corresponds to an abrupt TiO_2
(001)-layer termination of STO. This is also the composition which gives the
largest p-type Schottky barrier height in our calculations.


title:
A Synergistic Approach for Recovering Occlusion-Free Textured 3D Maps of
  Urban Facades from Heterogeneous Cartographic Data

abstract:
  In this paper we present a practical approach for generating an
occlusion-free textured 3D map of urban facades by the synergistic use of
terrestrial images, 3D point clouds and area-based information. Particularly in
dense urban environments, the high presence of urban objects in front of the
facades causes significant difficulties for several stages in computational
building modeling. Major challenges lie on the one hand in extracting complete
3D facade quadrilateral delimitations and on the other hand in generating
occlusion-free facade textures. For these reasons, we describe a
straightforward approach for completing and recovering facade geometry and
textures by exploiting the data complementarity of terrestrial multi-source
imagery and area-based information.


title: Denjoy, Demuth, and Density

abstract:
  We consider effective versions of two classical theorems, the Lebesgue
density theorem and the Denjoy-Young-Saks theorem. For the first, we show that
a Martin-Loef random real $z\in [0,1]$ is Turing incomplete if and only if
every effectively closed class $C \subseteq [0,1]$ containing $z$ has positive
density at $z$. Under the stronger assumption that $z$ is not LR-hard, we show
that $z$ has density-one in every such class. These results have since been
applied to solve two open problems on the interaction between the Turing
degrees of Martin-Loef random reals and $K$-trivial sets: the non-cupping and
covering problems.
  We say that $f\colon[0,1]\to\mathbb{R}$ satisfies the Denjoy alternative at
$z \in [0,1]$ if either the derivative $f'(z)$ exists, or the upper and lower
derivatives at $z$ are $+\infty$ and $-\infty$, respectively. The
Denjoy-Young-Saks theorem states that every function
$f\colon[0,1]\to\mathbb{R}$ satisfies the Denjoy alternative at almost every
$z\in[0,1]$. We answer a question posed by Kucera in 2004 by showing that a
real $z$ is computably random if and only if every computable function $f$
satisfies the Denjoy alternative at $z$.
  For Markov computable functions, which are only defined on computable reals,
we can formulate the Denjoy alternative using pseudo-derivatives. Call a real
$z$ DA-random if every Markov computable function satisfies the Denjoy
alternative at $z$. We considerably strengthen a result of Demuth (Comment.
Math. Univ. Carolin., 24(3):391--406, 1983) by showing that every Turing
incomplete Martin-Loef random real is DA-random. The proof involves the notion
of non-porosity, a variant of density, which is the bridge between the two
themes of this paper. We finish by showing that DA-randomness is incomparable
with Martin-Loef randomness.


title:
Constraints on Lorentz Invariance Violation with Fermi-LAT Observations
  of Gamma-Ray Bursts

abstract:
  Some Quantum Gravity (QG) theories allow for a violation of Lorentz
invariance (LIV), manifesting as a dependence of the velocity of light in
vacuum on its energy. If such a dependence exists, then photons of different
energies emitted together by a distant source will arrive at the Earth at
different times. High-energy (GeV) transient emissions from distant
astrophysical sources such as Gamma-ray Bursts (GRBs) and Active Galaxy Nuclei
can be used to search for and constrain LIV. The Fermi collaboration has
previously analyzed two GRBs in order to put constraints on the dispersion
parameter in vacuum, and on the energy scale at which QG effects causing LIV
may arise. We used three different methods on four bright GRBs observed by the
Fermi-LAT to get more stringent and robust constraints. No delays have been
detected and strong limits on the QG energy scale are derived: for linear
dispersion we set tight constraints placing the QG energy scale above the
Planck mass; a quadratic leading LIV effect is also constrained.


title: Novel Six-Quark Hidden-Color Dibaryon States in QCD

abstract:
  The recent observation of a hadronic resonance $d^*$ in the proton-neutron
system with isospin $I = 0$ and spin-parity $J^P = 3^+$ raises the possibility
of producing other novel six-quark dibaryon configurations allowed by QCD. A
dramatic example of an exotic six-quark color-singlet system is the charge
$Q=+4$, isospin I=3, $I^z=+3$ $|uuuuuu>$ state which couples strongly to
$\Delta^{++}$ + $\Delta^{++} .$ The width and decay properties of such
six-quark resonances could be regarded as manifestations of "hidden-color"
six-quark configurations, a first-principle prediction of QCD -- SU(3)-color
gauge theory for the deuteron distribution amplitude. Other implications and
possible future experiments are discussed.


title:
A novel space division multiplexing system for free space optical
  communications

abstract:
  We propose a novel space division multiplexing (SDM) technique based on
spatial phase encoding, which may provide a new perspective beyond the
conventional SDM in free space optical communications, such as multiplexing of
orbital angular momentum (OAM). In our scheme, Gaussian beams are multiplexed
with a set of spatial phase masks, and then transmitted in the Fourier domain
via spherical lens. And another phase masks with matched patterns sandwiched by
two lenses are used to de-multiplex the corresponding channels. Three different
phase masks, namely, planar linear encoding, radial linear encoding and hybrid
of radial and azimuthal linear encoding, are proposed and analyzed. The
multiplexing and de-multiplexing of Gaussian beams are successfully implemented
using these phase encoding approaches. We prove that the OAM multiplexing and
radial phase encoding can be combined to further increase the communications
capacity in free space


title:
Updating constraints on inflationary features in the primordial power
  spectrum with the Planck data

abstract:
  We present new constraints on possible features in the primordial
inflationary density perturbations power spectrum in light of the recent Cosmic
Microwave Background Anisotropies measurements from the Planck satellite. We
found that the Planck data hints for the presence of features in two different
ranges of angular scales, corresponding to multipoles 10< l <60 and 150< l <
300, with a decrease in the best fit chi^2 value with respect to the
featureless "vanilla" LCDM model of Delta chi^2 around 9 in both cases.


title:
A simplified view of blazars: comparison with multi-frequency
  observations

abstract:
  We have recently proposed a new scenario where blazars are classified as
flat-spectrum radio quasars or BL Lacs according to the prescriptions of
unified schemes, and to a varying combination of Doppler boosted radiation from
the jet, emission from the accretion disk, the broad line region, and light
from the host galaxy. This mix of different components leads to strong
selection effects, which are properly taken into account in our scheme. We
describe here the main features of our approach, which solves many
long-standing issues of blazar research, give the most important results, and
discuss its implications and testable predictions.


title: B-spline one-center method for molecular Hartree-Fock calculations

abstract:
  We introduce one-center method in spherical coordinates to carry out
Hartree-Fock calculations. Both the radial wave function and the angular wave
function are expanded by B-splines, and the radial knots and angular knots are
adjusted to deal with cusps properly, resulting in the significant improvement
of convergence for several typical closed-shell diatomic molecules. B-splines
could represent both the bound state and continuum state wave function
properly, and the present approach has been applied to investigating ionization
dynamics for H$_2$ in the intense laser field adopting single-active-electron
model.


title:
Controllable microwave three-wave mixing via a single three-level
  superconducting quantum circuit

abstract:
  Three-wave mixing in second-order nonlinear optical processes cannot occur in
atomic systems due to the electric-dipole selection rules. In contrast, we
demonstrate that second-order nonlinear processes can occur in a
superconducting quantum circuit (i.e., a superconducting artificial atom) when
the inversion symmetry of the potential energy is broken by simply changing the
applied magnetic flux. In particular, we show that difference- and
sum-frequencies (and second harmonics) can be generated in the microwave regime
in a controllable manner by using a single three-level superconducting flux
quantum circuit (SFQC). For our proposed parameters, the frequency tunability
of this circuit can be achieved in the range of about 17 GHz for the
sum-frequency generation, and around 42 GHz (or 26 GHz) for the
difference-frequency generation. Our proposal provides a simple method to
generate second-order nonlinear processes within current experimental
parameters of SFQCs.


title: Classification of modules for infinite-dimensional string algebras

abstract:
  We relax the definition of a string algebra to also include
infinite-dimensional algebras such as k[x,y]/(xy). Using the functorial
filtration method, which goes back to Gelfand and Ponomarev, we show that
finitely generated and artinian modules (and more generally finitely controlled
and pointwise artinian modules) are classified in terms of string and band
modules. This subsumes the known classifications of finite-dimensional modules
for string algebras and of finitely generated modules for k[x,y]/(xy). Unlike
in the finite-dimensional case, the words parameterizing string modules may be
infinite.


title: Modular Inverses and Chinese Remainder Algorithm

abstract:
  This paper introduces two forms of modular inverses and proves their
reciprocity formulas respectively. These formulas are then applied to formulate
new and generalized algorithm for computing these modular inverses. The same
algorithm is also shown to be applicable for the Chinese Remainder problem,
i.e., simultaneous linear congruence equations, for co-prime moduli as well as
non-co-prime moduli.


title:
A new diamond biosensor with integrated graphitic microchannels for
  detecting quantal exocytic events from chromaffin cells

abstract:
  The quantal release of catecholamines from neuroendocrine cells is a key
mechanism which has been investigated with a broad range of materials and
devices, among which carbon-based materials such as carbon fibers, diamond-like
carbon, carbon nanotubes and nanocrystalline diamond. In the present work we
demonstrate that a MeV-ion-microbeam lithographic technique can be successfully
employed for the fabrication of an all-carbon miniaturized cellular bio-sensor
based on graphitic micro-channels embedded in a single-crystal diamond matrix.
The device was functionally characterized for the in vitro recording of quantal
exocytic events from single chromaffin cells, with high sensitivity and
signal-to-noise ratio, opening promising perspectives for the realization of
monolithic all-carbon cellular biosensors.


title:
Development of a language and its enacting engine for the unified
  discovery of heterogeneous services

abstract:
  Service orientation fosters a high-level model for distributed applications
development, which is based on the discovery, composition and reuse of existing
software services. However, the heterogeneity among current service-oriented
technologies renders the important task of service discovery tedious and
ineffective. This dissertation proposes a new approach to address this
challenge. Specifically, it contributes a framework supporting the unified
discovery of heterogeneous services, with a focus on web, peer-to-peer, and
grid services. The framework comprises a service query language and its
enacting service discovery engine. Overall, the proposed solution is
characterized by generality and flexibility, which are ensured by appropriate
abstractions, extension points, and their sup- porting mechanisms. The
viability, performance, and effectiveness of the proposed framework are
demonstrated by experimental measurements.


title: The multi-frequency multi-temporal sky

abstract:
  Contemporary astronomy benefits of very large and rapidly growing amounts of
data in all bands of the electromagnetic spectrum, from long-wavelength radio
waves to high energy gamma-rays. Astronomers normally specialize in data taken
in one particular energy window, however the advent of data centers world-wide
and of the Virtual Observatory, which provide simple and open access to quality
data in all energy bands taken at different epochs, is making multi-frequency
and multi-epoch astronomy much more affordable than in the past. New tools
designed to combine and analyze these data sets are being developed with the
aim of visualizing observational results and extracting information about the
physical processes powering cosmic sources in ways that were not possible
before. In this contribution blazars, a type of cosmic sources that emit highly
variable radiation at all frequencies, are used as an example to describe the
possibilities of this type of astronomy today, and the discovery potential for
the near future.


title: Learning-Based Procedural Content Generation

abstract:
  Procedural content generation (PCG) has recently become one of the hottest
topics in computational intelligence and AI game researches. Among a variety of
PCG techniques, search-based approaches overwhelmingly dominate PCG development
at present. While SBPCG leads to promising results and successful applications,
it poses a number of challenges ranging from representation to evaluation of
the content being generated. In this paper, we present an alternative yet
generic PCG framework, named learning-based procedure content generation
(LBPCG), to provide potential solutions to several challenging problems in
existing PCG techniques. By exploring and exploiting information gained in game
development and public beta test via data-driven learning, our framework can
generate robust content adaptable to end-user or target players on-line with
minimal interruption to their experience. Furthermore, we develop enabling
techniques to implement the various models required in our framework. For a
proof of concept, we have developed a prototype based on the classic open
source first-person shooter game, Quake. Simulation results suggest that our
framework is promising in generating quality content.


title:
Updated IAA RAS Planetary Ephemerides-EPM2011 and Their Use in
  Scientific Research

abstract:
  The EPM2011 ephemerides are computed using an updated dynamical model, new
values of the parameters, and an extended observation database that contains
about 680 000 positional measurements of various types obtained from 1913 to
2011. The dynamical model takes into account mutual perturbations of the major
planets, the Sun, the Moon, 301 massive asteroids, and 21 of the largest
trans-Neptunian objects (TNOs), as well as perturbations from the other
main-belt asteroids and other TNOs. The EPM ephemerides are computed by
numerical integration of the equations of motion of celestial bodies in the
parameterized post-Newtonian n-body metric in the BCRS coordinate system for
the TDB time scale over a 400-year interval. The ephemerides were oriented to
the ICRF system using 213 VLBI observations (taken from 1989 to 2010) of
spacecraft near planets with background quasars, the coordinates of which are
given in the ICRF system. The accuracy of the constructed ephemerides was
verified by comparison with observations and JPL independent ephemerides DE424.
  The EPM ephemerides are used in astronavigation (they form the basis of the
{\it Astronomical Yearbook} and are planned to be utilized in GLONASS and
LUNA-RESURS programs) and various research, including the estimation of the
solar oblateness, the parameters of the rotation of Mars, and the total mass of
the asteroid main belt and TNOs, as well as the verification of general
relativity, the secular variations of the Sun's mass and the gravitational
constant, and the limits on the dark matter density in the Solar System.
  The EPM ephemerides, together with the corresponding time differences TT -
TDB and the coordinates of seven additional objects (Ceres, Pallas, Vesta,
Eris, Haumea, Makemake, and Sedna), are available at
ftp://quasar.ipa.nw.ru/incoming/EPM.


title:
Active plasmonic switching at mid-infrared wavelengths with graphene
  ribbon arrays

abstract:
  An active plasmonic switch based on single- and few-layer doped graphene
ribbon array operating in the mid-infrared spectrum is investigated with
theoretical and numerical calculations. It is shown that significant resonance
wavelength shifts and modulation depths can be achieved with a slight variation
of the doping concentration of the graphene ribbon. The few-layer graphene
ribbon array device outperforms the single-layer one in terms of the achievable
modulation depth. Our simulations reveal that, by modulating the Fermi-energy
level between 0.2 eV and 0.25 eV, a four-layer graphene ribbon array device can
achieve a modulation depth and resonance wavelength shift of ~13 dB and 0.94
micron respectively, compared to ~2.8 dB and 1.85 micron for a single-layer
device. Additionally, simple fitting models to predict the modulation depth and
the resonance wavelength shift are proposed. These prospects pave the way
towards ultrafast active graphene-based plasmonic devices for infrared and THz
applications.


title:
Non-collective excitations in low-energy heavy-ion reactions:
  applicability of the random-matrix model

abstract:
  We investigate the applicability of a random-matrix model to the description
of non-collective excitations in heavy-ion reactions around the Coulomb
barrier. To this end, we study fusion in the reaction $^{16}$O + $^{208}$Pb,
taking account of the known non-collective excitations in the $^{208}$Pb
nucleus. We show that the random-matrix model for the corresponding couplings
reproduces reasonably well the exact calculations, obtained using empirical
deformation parameters. This implies that the model may provide a powerful
method for systems in which the non-collective couplings are not so well known.


title:
Magnetic fan structures in Ba$_{0.5}$Sr$_{1.5}$Zn$_2$Fe$_{12}$O$_{22}$
  hexaferrite revealed by resonant soft X-ray diffraction

abstract:
  The hexaferrites are known to exhibit a wide range of magnetic structures,
some of which are connected to important technological applications and display
magnetoelectric properties. We present data on the low field magnetic
structures stabilised in a Y-type hexaferrite as observed by resonant soft
X-ray diffraction. The helical spin block arrangement that is present in zero
applied magnetic field becomes fan-like as a field is applied in plane. The
propagation vectors associated with each fan structure are studied as a
function of field, and a new magnetic phase is reported. Mean field
calculations indicate this phase should stabilise close to the boundary of the
previously reported phases.


title: Avoiding \sigma-porous sets in Hilbert spaces

abstract:
  We give a constructive proof that any $\sigma$-porous subset of a Hilbert
space has Lebesgue measure zero on typical $C^{1}$ curves. Further, we discover
that this result does not extend to all forms of porosity; we find that even
power-$p$ porous sets may meet many $C^{1}$ curves in positive measure.


title: Feedback control of flow alignment in sheared liquid crystals

abstract:
  Based on a continuum theory, we investigate the manipulation of the
non-equilibrium behavior of a sheared liquid crystal via closed-loop feedback
control. Our goal is to stabilize a specific dynamical state, that is, the
stationary "flow-alignment", under conditions where the uncontrolled system
displays oscillatory director dynamics with in-plane symmetry. To this end we
employ time-delayed feedback control (TDFC), where the equation of motion for
the ith component, q_i(t), of the order parameter tensor is supplemented by a
control term involving the difference q_i(t)-q_i(t-\tau). In this diagonal
scheme, \tau is the delay time. We demonstrate that the TDFC method
successfully stabilizes flow alignment for suitable values of the control
strength, K, and \tau; these values are determined by solving an exact
eigenvalue equation. Moreover, our results show that only small values of K are
needed when the system is sheared from an isotropic equilibrium state, contrary
to the case where the equilibrium state is nematic.


title:
Cytoplasmic Streaming in Plant Cells Emerges Naturally by Microfilament
  Self-Organization

abstract:
  Many cells exhibit large-scale active circulation of their entire fluid
contents, a process termed cytoplasmic streaming. This phenomenon is
particularly prevalent in plant cells, often presenting strikingly regimented
flow patterns. The driving mechanism in such cells is known: myosin-coated
organelles entrain cytoplasm as they process along actin filament bundles fixed
at the periphery. Still unknown, however, is the developmental process which
constructs the well-ordered actin configurations required for coherent
cell-scale flow. Previous experimental works on streaming regeneration in cells
of Characean algae, whose longitudinal flow is perhaps the most regimented of
all, hint at an autonomous process of microfilament self-organization driving
the formation of streaming patterns during morphogenesis. Working from first
principles, we propose a robust model of streaming emergence that combines
motor dynamics with both micro- and macroscopic hydrodynamics to explain how
several independent processes, each ineffectual on its own, can reinforce to
ultimately develop the patterns of streaming observed in the Characeae and
other streaming species.


title:
Cooperative Motion of Active Brownian Spheres in Three-Dimensional Dense
  Suspensions

abstract:
  The structural and dynamical properties of suspensions of self-propelled
Brownian particles of spherical shape are investigated in three spatial
dimensions. Our simulations reveal a phase separation into a dilute and a dense
phase, above a certain density and strength of self-propulsion. The packing
fraction of the dense phase approaches random close packing at high activity,
yet the system remains fluid. Although no alignment mechanism exists in this
model, we find long-lived cooperative motion of the particles in the dense
regime. This behavior is probably due to an interface-induced sorting process.
Spatial displacement correlation functions are nearly scale-free for systems
with densities close to or above the glass transition density of passive
systems.

categories: cond-mat.soft physics.bio-ph physics.comp-ph q-bio.CB


title: Influence of multi-electronic states on few-quantum-dot nanolasers

abstract:
  We present an experimental and theoretical study on the gain mechanism in a
photonic-crystal-cavity nanolaser with embedded quantum dots. From
time-resolved measurements at low excitation power we find that four excitons
are coupled to the cavity. At high excitation power we observe a smooth
low-threshold transition from spontaneous emission to lasing. Before lasing
emission sets in, however, the excitons are observed to saturate, and the gain
required for lasing originates rather from multi-electronic transitions, which
give rise to a broad emission background. We compare the experiment to a model
of quantum-dot microcavity lasers and find that the number of emitters feeding
the cavity must greatly exceed four, which confirms that the gain is provided
by multi-electronic states. Our results are consistent with theoretical
predictions.


title:
Causal dynamical triangulation for non-critical open-closed string field
  theory

abstract:
  We extend the 2 dimensional Causal Dynamical Triangulation (CDT) model from
the usual model of closed string to the one of open-closed string. The
matrix-vector model describing the loop gas model is modified so as to possess
the nature of the CDT, i.e. the time foliation structure. Stochastic
quantization method produces interactions of loop and line variables similar to
those in the non-critical open-closed string field theories. By taking an
appropriate scaling, we realize an extended model of the generalized CDT
(GCDT), which keeps the causality in a broad sense.


title:
Resonance scattering and the passage to bound states in the field of
  near-black-hole objects

abstract:
  We examine the spectrum of a massive scalar particle interacting with the
strong gravitational field of a static, spherically symmetric object which is
not quite massive enough to be a black hole. As was found in the case of
massless particles, there exists a dense spectrum of long lived resonances
(meta-stable states), which leads to an energy-averaged cross section for
particle capture which approaches the absorption cross-section for a
Schwarzschild black hole. However, the generalisation to non-zero mass
introduces new phenomena, along with important qualitative changes to the
scattering properties. In contrast to the massless case, there exists a
spectrum of bound states with almost identical structure to that of the
resonances, allowing for the possibility of radiative transitions and particle
capture. The resonance lifetimes for elastic processes are parametrically
larger than for massless particles, meaning the absorption cross-section
approaches the black hole case faster than for massless scalars.


title: Driving Disk Winds and Heating up Hot Coronae by MRI Turbulence

abstract:
  We investigate the formation of hot coronae and vertical outflows in
accretion disks by magneto-rotational turbulence. We perform local
three-dimensional (3D) MHD simulations with the vertical stratification by
explicitly solving an energy equation with various effective ratios of specific
heats, gamma. Initially imposed weak vertical magnetic fields are effectively
amplified by magnetorotational instability (MRI) and winding due to the
differential rotation. In the isothermal case (gamma=1), the disk winds are
mainly driven by the Poynting flux associated with the MHD turbulence and show
quasi-periodic intermittency. On the other hand, in the non-isothermal cases
with gamma >~ 1.1, the regions above 1-2 scale heights from the midplane are
effectively heated up to form coronae with the temperature of ~ 50 times of the
initial value, which are connected to the cooler midplane region through the
pressure-balanced transition regions. As a result, the disk winds are mainly
driven by the gas pressure with exhibiting more time-steady nature, although
the nondimensional time-averaged mass loss rates are similar to that of the
isothermal case. Sound-like waves are confined in the cool midplane region in
these cases, and the amplitude of the density fluctuations is larger than that
of the isothermal case.


title: Bockstein cohomology of associated graded rings

abstract:
  Let $(A,\mathfrak{m})$ be a Cohen-Macaulay local ring of dimension $d$ and
let $I$ be an $\mathfrak{m}$-primary ideal. Let $G$ be the associated graded
ring of $A$ \wrt \ $I$ and let $\R = A[It,t^{-1}]$ be the extended Rees ring of
$A$ with respect to $I$. Notice $t^{-1}$ is a non-zero divisor on $\R$ and
$\R/t^{-1}\R = G$. So we have \textit{Bockstein operators} $\beta^i \colon
H^i_{G_+}(G)(-1) \rt H^{i+1}_{G_+}(G)$ for $i \geq 0$. Since
$\beta^{i+1}(+1)\circ \beta^i = 0$ we have \textit{Bockstein cohomology}
modules $BH^i(G)$ for $i = 0,\ldots,d$. In this paper we show that certain
natural conditions on $I$ implies vanishing of some Bockstein cohomology
modules.


title:
Five dimensional almost para-cosymplectic manifolds with contact Ricci
  potential

abstract:
  There are studied in details 5-dimensional pseudo-Riemannian manifolds
equipped with the structure analogous to the almost cosymplectic (almost
coKaehler) structure. The curvature by assumption commutes with the structure
affinor and all these manifolds are Walker spaces. There are obtained
classifications for manifolds for contact Ricci potential, locally flat
manifolds and described all connected, simply connected Lie groups admiting
left-invariant structure. There are some other more general results.


title:
Robust, frequency-stable and accurate mid-IR laser spectrometer based on
  frequency comb metrology of quantum cascade lasers up-converted in
  orientation-patterned GaAs

abstract:
  We demonstrate a robust and simple method for measurement, stabilization and
tuning of the frequency of cw mid-infrared (MIR) lasers, in particular of
quantum cascade lasers. The proof of principle is performed with a quantum
cascade laser at 5.4 \mu m, which is upconverted to 1.2 \mu m by sum-frequency
generation in orientation-patterned GaAs with the output of a standard
high-power cw 1.5 \mu m fiber laser. Both the 1.2 \mu m and the 1.5 \mu m waves
are measured by a standard Er:fiber frequency comb. Frequency measurement at
the 100 kHz-level, stabilization to sub-10 kHz level, controlled frequency
tuning and long-term stability are demonstrated.


title: The Riemann Hypothesis for Dirichlet $L$ Functions

abstract:
  This paper studies the connections between the zeros and their distribution
functions for two particular Dirichlet $L$ functions: the Riemann zeta
function, and the Catalan beta function, also known as the Dirichlet beta
function. It is shown that the Riemann hypothesis holds for the Dirichlet beta
function $L_{-4}(s)$ if and only if it holds for $\zeta (s)$- a particular case
of the Generalized Riemann Hypothesis.


title:
Robust L_infinity-induced deconvolution filtering for linear stochastic
  systems and its application to fault reconstruction

abstract:
  The problem of stationary robust L_infinity-induced deconvolution filtering
for the uncertain continuous-time linear stochastic systems is addressed. The
state space model of the system contains state- and input-dependent noise and
deterministic parameter uncertainties residing in a given polytope. In the
presence of input-dependent noise, we extend the derived lemma in Berman and
Shaked (2010) characterizing the induced L_infinity norm by linear matrix
inequalities (LMIs), according to which we solve the deconvolution problem in
the quadratic framework. By decoupling product terms between the Lyapunov
matrix and system matrices, an improved version of the proposed
L_infinity-induced norm bound lemma for continuous-time stochastic systems is
obtained, which allows us to realize exploit parameter-dependent stability idea
in the deconvolution filter design. The theories presented are utilized for
sensor fault reconstruction in uncertain linear stochastic systems. The
effectiveness and advantages of the proposed design methods are shown via two
numerical examples.


title: Detecting wheels

abstract:
  A \emph{wheel} is a graph made of a cycle of length at least~4 together with
a vertex that has at least three neighbors in the cycle. We prove that the
problem whose instance is a graph $G$ and whose question is "does $G$ contains
a wheel as an induced subgraph" is NP-complete. We also settle the complexity
of several similar problems.


title: Light Curves from Supernova Shock Breakout through an Extended Wind

abstract:
  Recent observations suggest that some supernovae may be the result of an
explosion into an optically thick circumstellar material, the product of
pre-explosion mass-loss (wind) by the progenitor star. This scenario has been
studied previously both analytically and numerically. However, many previous
studies base their analysis on the diffusion approximation for radiation
transfer, which is inappropriate in the optically thin outer layers of the
wind. Here we study the deviations from diffusion, and calculate light curves
more accurately using a Monte Carlo approach to photon transfer. We distinguish
between "compact" winds, for which the diffusion approximation is appropriate,
and "extended" winds, which require a more delicate treatment of the radiation.
We show that this effect is more significant than that of the light travel time
difference to a distant observer, which has a secondary influence on the light
curves of extended-wind systems. We also comment on the applicability of the
widely used flux-limited diffusion approximation in this context: we find that
it generally does not reproduce the Monte Carlo results. The flux-limited
diffusion approximation leads to results which are not only quantitatively, but
also qualitatively wrong, in the extended-wind regime.


title:
Cavity polariton in a quasi-lattice of qubits and its selective
  radiation

abstract:
  In a circuit quantum eletrodynamic system, a chain of N qubits
inhomogeneously coupled to a cavity field forms a mesoscopic quasi-lattice,
which is characterized by its degree of deformation from a normal lattice. This
deformation is a function of the relative spacing, that is the ratio of the
qubit spacing to the cavity wavelength. A polariton mode arise in the
quasi-lattice as the dressed mode of the lattice excitation by the cavity
photon. We show that the transition probability of the polariton mode is either
enhanced or decreased compared to that of a single qubit by the deformation,
giving a selective spontaneous radiation spectrum. Further, unlike a
microscopic lattice with large-N limit and nearly zero relative spacing, the
polariton in the quasi-lattice has uneven decay rate over the relative spacing.
We show that this unevenness coincides with the cooperative emission effect
expected from the superradiance model, where alternative excitations in the
qubits of the lattice result in maximum decay.


title: The Main Sequence of three Red Supergiant Clusters

abstract:
  Massive clusters in our Galaxy are an ideal testbed to investigate the
properties and evolution of high mass stars. They provide statistically
significant samples of massive stars of uniform ages. To accurately determine
the intrinsic physical properties of these stars we need to establish the
distances, ages and reddening of the clusters. One avenue to achieve this is
the identification and characterisation of the main sequence members of red
supergiant rich clusters.
  Here we utilise publicly available data from the UKIDSS galactic plane
survey. We show that point spread function photometry in conjunction with
standard photometric decontamination techniques allows us to identify the most
likely main sequence members in the 10-20Myr old clusters RSGC1, 2, and 3. We
confirm the previous detection of the main sequence in RSGC2 and provide the
first main sequence detection in RSGC1 and RSGC3. There are in excess of 100
stars with more than 8Msun identified in each cluster. These main sequence
members are concentrated towards the spectroscopically confirmed red supergiant
stars. We utilise the J-K colours of the bright main sequence stars to
determine the K-band extinction towards the clusters. The differential
reddening is three times as large in the youngest cluster RSGC1 compared to the
two older clusters RSGC2 and RSGC3. Spectroscopic follow up of the cluster main
sequence stars should lead to more precise distance and age estimates for these
clusters as well as the determination of the stellar mass function in these
high mass environments.


title:
Coding with Scrambling, Concatenation, and HARQ for the AWGN Wire-Tap
  Channel: A Security Gap Analysis

abstract:
  This study examines the use of nonsystematic channel codes to obtain secure
transmissions over the additive white Gaussian noise (AWGN) wire-tap channel.
Unlike the previous approaches, we propose to implement nonsystematic coded
transmission by scrambling the information bits, and characterize the bit error
rate of scrambled transmissions through theoretical arguments and numerical
simulations. We have focused on some examples of Bose-Chaudhuri-Hocquenghem
(BCH) and low-density parity-check (LDPC) codes to estimate the security gap,
which we have used as a measure of physical layer security, in addition to the
bit error rate. Based on a number of numerical examples, we found that such a
transmission technique can outperform alternative solutions. In fact, when an
eavesdropper (Eve) has a worse channel than the authorized user (Bob), the
security gap required to reach a given level of security is very small. The
amount of degradation of Eve's channel with respect to Bob's that is needed to
achieve sufficient security can be further reduced by implementing scrambling
and descrambling operations on blocks of frames, rather than on single frames.
While Eve's channel has a quality equal to or better than that of Bob's
channel, we have shown that the use of a hybrid automatic repeat-request (HARQ)
protocol with authentication still allows achieving a sufficient level of
security. Finally, the secrecy performance of some practical schemes has also
been measured in terms of the equivocation rate about the message at the
eavesdropper and compared with that of ideal codes.


title:
Induced tunneling and localization for a quantum particle in tilted
  two-dimensional lattices

abstract:
  We consider a quantum particle in tilted two-dimensional lattices in the
tight-binding approximations. We found that for some lattice geometries and
certain orientations of the static force with respect to the lattice primary
axes the particle can freely move across the lattice in the direction
perpendicular to the vector of the static force. This effect is argued to be
analogue of the photon-induced tunneling in driven one-dimensional lattices.
The obtained dispersion relation for the transverse motion of the particle
draws this analogy further by eventually showing band collapses when a control
parameter is varied.


title: Local removable singularity theorems for minimal laminations

abstract:
  In this paper we prove a local removable singularity theorem for certain
minimal laminations with isolated singularities in a Riemannian three-manifold.
This removable singularity theorem is the key result used in our proof that a
complete, embedded minimal surface in $\mathbb{R}^3$ with quadratic decay of
curvature has finite total curvature.


title: Membrane Viscosity Determined from Shear-Driven Flow in Giant Vesicles

abstract:
  The viscosity of lipid bilayer membranes plays an important role in
determining the diffusion constant of embedded proteins and the dynamics of
membrane deformations, yet it has historically proven very difficult to
measure. Here we introduce a new method based on quantification of the
large-scale circulation patterns induced inside vesicles adhered to a solid
surface and subjected to simple shear flow in a microfluidic device. Particle
Image Velocimetry based on spinning disk confocal imaging of tracer particles
inside and outside of the vesicle, and tracking of phase-separated membrane
domains are used to reconstruct the full three-dimensional flow pattern induced
by the shear. These measurements show excellent agreement with the predictions
of a recent theoretical analysis, and allow direct determination of the
membrane viscosity.


title:
Optimized state independent entanglement detection based on geometrical
  threshold criterion

abstract:
  Experimental procedures are presented for the rapid detection of entanglement
of unknown arbitrary quantum states. The methods are based on the entanglement
criterion using accessible correlations and the principle of correlation
complementarity. Our first scheme essentially establishes the Schmidt
decomposition for pure states, with few measurements only and without the need
for shared reference frames. The second scheme employs a decision tree to speed
up entanglement detection. We analyze the performance of the methods using
numerical simulations and verify them experimentally for various states of two,
three and four qubits.


title:
Percolation model for a selective response of the resistance of
  composite semiconducting np-systems towards reducing gases

abstract:
  It is shown that a two-component percolation model can explain an
experimentally observed behavior, namely that a network built up by a mixture
of sintered nanocrystalline semiconducting n- and p-grains can exhibit
selective behavior, i.e. respond with a resistance increase when exposed to a
reducing gas A and with a resistance decrease in response to another reducing
gas B. To this end, a simple model is developed based on realistic assumptions
about the reactions on the grain surfaces. The resistance is calculated by
random walk simulations with nn-, pp- and np-bonds between the grains and the
results are found in very good agreement with the experiments. Contrary to
former assumptions, the np-bonds are crucial to obtain this accordance.


title: On asymptotically efficient statistical inference on a signal parameter

abstract:
  We consider the problems of confidence estimation and hypothesis testing on a
parameter of signal observed in Gaussian white noise. For these problems we
point out lower bounds of asymptotic efficiency in the zone of moderate
deviation probabilities. These lower bounds are versions of local asymptotic
minimax Hajek-Le Cam lower bound in estimation and the lower bound for Pitman
efficiency in hypothesis testing. The lower bounds were obtained for both
logarithmic and sharp asymptotic of moderate deviation probabilities.


title: Coloring perfect graphs with no balanced skew-partitions

abstract:
  We present an $O(n^5)$ algorithm that computes a maximum stable set of any
perfect graph with no balanced skew-partition. We present $O(n^7)$ time
algorithm that colors them.


title: On the dimension of Chowla-Milnor space

abstract:
  In a recent work, Gun, Murty and Rath defined the Chowla-Milnor space and
proved a non-trivial lower bound for these spaces. They also obtained a
conditional improvement of this lower bound and noted that an unconditional
improvement of their lower bound will lead to irrationality of $\zeta(k)/
\pi^k$ for odd positive integers $k>1$. In this paper, we give an alternate
proof of their theorem about the conditional lower bound.


title:
Rotational properties in even-even superheavy $^{254-258}$Rf nuclei
  based on total-Routhian-surface calculations

abstract:
  High-spin yrast structures of even-even superheavy nuclei $^{254-258}$Rf are
investigated by means of total-Routhian-surface approach in three-dimensional
($\beta_2, \gamma, \beta_4$) space. The behavior in the moments of inertia of
$^{256}$Rf is well reproduced by our calculations, which is attributed to the
$j_{15/2}$ neutron rotation-alignment. The competition between rotationally
aligned $i_{13/2}$ proton and $j_{15/2}$ neutron is discussed. High-spin
predictions are also made for its neighboring isotopes $^{254,258}$Rf.


title: Device-independent quantum key distribution based on measurement inputs

abstract:
  We provide an analysis of a new family of device independent quantum key
distribution (QKD) protocols with several novel features: (a) The bits used for
the secret key do not come from the results of the measurements on an entangled
state but from the choices of settings; (b) Instead of a single security
parameter (a violation of some Bell inequality) a set of them is used to
estimate the level of trust in the secrecy of the key. The main advantage of
these protocols is a smaller vulnerability to imperfect random number
generators made possible by feature (a). We prove the security and the
robustness of such protocols. We show that using our method it is possible to
construct a QKD protocol which retains its security even if the source of
randomness used by communicating parties is strongly biased. As a proof of
principle, an explicit example of a protocol based on the Hardy's paradox is
presented. Moreover, in the noiseless case, the protocol is secure in a natural
way against any type of memory attack, and thus allows to reuse the device in
subsequent rounds. We also analyse the robustness of the protocol using
semi-definite programming methods. Finally, we present a post-processing
method, and observe a paradoxical property that rejecting some random part of
the private data can increase the key rate of the protocol.


title: The Strong Chowla-Milnor spaces and a conjecture of Gun, Murty and Rath

abstract:
  In a recent work, Gun, Murty and Rath formulated the Strong Chowla-Milnor
conjecture and defined the Strong Chowla-Milnor space. In this paper, we prove
a non-trivial lower bound for the dimension of these spaces. We also obtain a
conditional improvement of this lower bound and noted that an unconditional
improvement of this lower bound will lead to irrationality of both $\zeta(k)$
and $\zeta(k)/ \pi^k$ for all odd positive integers $k>1$. Following Gun, Murty
and Rath, we define generalized Zagier spaces $V_p(K)$ for multiple zeta values
over a number field $K$. We prove that the dimension of $V_{4d+2}(K)$ for
$d\geq 1$, is at least 2, assuming a conjecture of Gun, Murty and Rath.


title: A note on the quintasymptotic prime ideals

abstract:
  Let $R$ denote a commutative Noetherian ring, $I$ an ideal of $R$, and let
$S$ be a multiplicatively closed subset of $R$. In \cite{Ra1}, Ratliff showed
that the sequence of sets ${\rm Ass}_RR/\bar{I}\subseteq {\rm Ass}_RR/\bar{I^2}
\subseteq {\rm Ass}_R R/\bar{I^3}\subseteq \dots $ increases and eventually
stabilizes to a set denoted $\bar{A^\ast}(I)$. In \cite{Mc2}, S. McAdam gave an
interesting description of $\bar{A^\ast}(I)$ by making use of $R[It,t^{-1}]$,
the Rees ring of $I$. In this paper, we give a second description of
$\bar{A^\ast}(I)$ by making use of the Rees valuation rings of $I$. We also
reprove a result concerning when $\bar{I^n}R_S\cap R=\bar{I^n}$ for all
integers $n>0$.


title:
The virtual observatory service TheoSSA: Establishing a database of
  synthetic stellar flux standards. I. NLTE spectral analysis of the DA-type
  white dwarf G 191-B2B

abstract:
  H-rich, DA-type white dwarfs are particularly suited as primary standard
stars for flux calibration. State-of-the-art NLTE models consider opacities of
species up to trans-iron elements and provide reliable synthetic
stellar-atmosphere spectra to compare with observation.
  We establish a database of theoretical spectra of stellar flux standards that
are easily accessible via a web interface.
  In the framework of the Virtual Observatory, the German Astrophysical Virtual
Observatory developed the registered service TheoSSA. It provides easy access
to stellar spectral energy distributions (SEDs) and is intended to ingest SEDs
calculated by any model-atmosphere code. In case of the DA white dwarf G
191-B2B, we demonstrate that the model reproduces not only its overall
continuum shape but also the numerous metal lines exhibited in its ultraviolet
spectrum.
  TheoSSA is in operation and contains presently a variety of SEDs for DA white
dwarfs. It will be extended in the near future and can host SEDs of all primary
and secondary flux standards. The spectral analysis of G 191-B2B has shown that
our hydrostatic models reproduce the observations best at an effective
temperature of 60000 +/- 2000K and a surface gravity of log g = 7.60 +/- 0.05.
We newly identified Fe VI, Ni VI, and Zn IV lines. For the first time, we
determined the photospheric zinc abundance with a logarithmic mass fraction of
-4.89 (7.5 times solar). The abundances of He (upper limit), C, N, O, Al, Si,
O, P, S, Fe, Ni, Ge, and Sn were precisely determined. Upper abundance limits
of 10% solar were derived for Ti, Cr, Mn, and Co.
  The TheoSSA database of theoretical SEDs of stellar flux standards guarantees
that the flux calibration of all astronomical data and cross-calibration
between different instruments can be based on the same models and SEDs
calculated with different model-atmosphere codes and are easy to compare.


title:
The Digamma function, Euler-Lehmer constants and their $p$-adic
  counterparts

abstract:
  The goal of this article is twofold. We first extend a result of Murty and
Saradha \cite{MS} related to the digamma function at rational arguments.
Further, we extend another result of the same authors \cite{MS1} about the
nature of $p$-adic Euler-Lehmer constants.


title:
Cauchy Problem for Fractional Diffusion-Wave Equations with Variable
  Coefficients

abstract:
  We consider an evolution equation with the Caputo-Dzhrbashyan fractional
derivative of order $\alpha \in (1,2)$ with respect to the time variable, and
the second order uniformly elliptic operator with variable coefficients acting
in spatial variables. This equation describes the propagation of stress pulses
in a viscoelastic medium. Its properties are intermediate between those of
parabolic and hyperbolic equations. In this paper, we construct and investigate
a fundamental solution of the Cauchy problem, prove existence and uniqueness
theorems for such equations.


title:
Development of High Intensity Laser-Electron Photon Beams up to 2.9 GeV
  at the SPring-8 LEPS Beamline

abstract:
  A laser-Compton backscattering beam, which we call a `Laser-Electron Photon'
beam, was upgraded at the LEPS beamline of SPring-8. We accomplished the gains
in backscattered photon beam intensities by factors of 1.5--1.8 with the
injection of two adjacent laser beams or a higher power laser beam into the
storage ring. The maximum energy of the photon beam was also extended from 2.4
GeV to 2.9 GeV with deep-ultraviolet lasers. The upgraded beams have been
utilized for hadron photoproduction experiments at the LEPS beamline. Based on
the developed methods, we plan the simultaneous injection of four high power
laser beams at the LEPS2 beamline, which has been newly constructed at
SPring-8. As a simulation result, we expect an order of magnitude higher
intensities close to 10$^7$ sec$^{-1}$ and 10$^6$ sec$^{-1}$ for tagged photons
up to 2.4 GeV and 2.9 GeV, respectively.


title: Resultants and the Borcherds Phi-function

abstract:
  The Borcherds Phi-function is the automorphic form on the moduli space of
Enriques surfaces characterizing the discriminant locus. In this paper, we give
an algebro-geometric construction of the Borcherds Phi-function.


title:
Vacuum nanogap formation in multilayer structures by an
  adhesion-controlled process

abstract:
  In this study, we regulate adhesion between thin metal films to produce a
large-area vacuum nanogap for electron tunneling. Multilayer structures
comprising thin metal films with adjustable adhesion were fabricated. The
Cu/Ag/Ti/Si structures were grown on Si substrates and include thin Ti and Ag
films and a thick Cu layer. The Ag and Ti films were deposited on the Si
substrate under vacuum, and a thick Cu layer was subsequently electroplated
onto the Ag surface. Later, the sandwich was separated and a vacuum nanogap was
opened to produce two Ag/Cu and Ti/Si conformal electrodes. The adhesion
strength between the Ti and Ag films was precisely adjusted by exposing the
structures to dry O2 after Ti growth but before Ag growth. The resulting
adhesion needed to be sufficiently high to allow electroplating of Cu and
sufficiently low to allow subsequent separation. Either heating or cooling was
used to separate the sandwiches. T he structures separated as a result of the
different thermal expansion parameters of the Si and Cu electrodes and the low
adhesion between the Ti and Ag layers. After separation, the Ag and Ti surfaces
were analyzed optically using a Michelson interferometer. Adhesion regulation
and optimization of the electroplating regime allowed fabrication of two
conformal electrodes with a nanogap smaller than 5 nm and an area larger than 7
mm2. Such electrodes can be used for efficient energy conversion and cooling in
the mixed thermionic and thermotunneling regime.


title:
A simpler prescription for MHV graviton tree amplitudes in superstring
  theory

abstract:
  We extend the Berkovits-Maldacena prescription for MHV amplitudes of the open
superstring to the closed superstring, showing that in the \alpha'=0 limit it
reduces to the result of supergravity found recently by Hodges. We also verify
that this prescription calculates the correct superstring tree level MHV
amplitude for 4 gravitons including \alpha' corrections.


title:
The Clusters AgeS Experiment (CASE): Variable Stars in the Globular
  Cluster 47 Tucanae

abstract:
  Based on over 5400 BV images of 47 Tuc collected between 1998 and 2010 we
obtained light curves of 65 variables, 21 of which are newly detected objects.
New variables are located mostly just outside of the core in a region poorly
studied by earlier surveys of the cluster. Among them there are four detached
eclipsing binaries and five likely optical counterparts of X-ray sources. Two
detached systems are promising targets for follow-up observations. We briefly
discuss properties of the most interesting new variables.


title:
Uniform lower bound for the least common multiple of a polynomial
  sequence

abstract:
  Let $n$ be a positive integer and $f(x)$ be a polynomial with nonnegative
integer coefficients. We prove that ${\rm lcm}_{\lceil n/2\rceil \le i\le n}
\{f(i)\}\ge 2^n$ except that $f(x)=x$ and $n=1, 2, 3, 4, 6$ and that $f(x)=x^s$
with $s\ge 2$ being an integer and $n=1$, where $\lceil n/2\rceil$ denotes the
smallest integer which is not less than $n/2$. This improves and extends the
lower bounds obtained by Nair in 1982, Farhi in 2007 and Oon in 2013.


title:
Impurities with retarded interaction with quasiparticles in a s-wave
  superconductor

abstract:
  A perturbation theory and a diagram technique for a disordered metal are
proposed when scattering of quasiparticles by nonmagnetic impurities is caused
with a retarded interaction. The perturbation theory generalizes a case of the
elastic scattering in a disordered metal. Eliashberg equations for s-wave
superconductivity are generalized for such a disordered superconductor.
Anderson's theorem is found to be violated in the sense that embedding of the
impurities into a s-wave superconductor increases its critical temperature. We
showed the amplification of superconducting properties is a result of
nonelastic effects in a scattering by the impurities.


title:
Slaving of the magnetic moment canting to the correlated oxygen rotation
  in Sr2IrO4 revealed by X-ray resonant scattering

abstract:
  Sr2IrO4 is a prototype of the class of Mott insulators in the strong
spin-orbit interaction (SOI) limit described by a $J_{\mathrm{eff}}=1/2$ ground
state. In Sr2IrO4, the strong SOI is predicted to manifest itself in the
slaving of the canting of the magnetic moments to the correlated rotation by
11.8(1)$^{\circ}$ of the oxygen octahedra that characterizes its distorted
layered perovskite structure. Using X-ray resonant scattering at the Ir $L_3$
edge we have measured accurately the intensities of Bragg peaks arising from
different components of the magnetic structure. From a careful comparison of
integrated intensities of peaks due to basal-plane antiferromagnetism, with
those due to b-axis ferromagnetism, we deduce a canting of the magnetic moments
of 12.2(8)$^{\circ}$. We thus confirm that in Sr2IrO4 the magnetic moments
rigidly follow the rotation of the oxygen octahedra, indicating that, even in
the presence of significant non-cubic structural distortions, it is a close
realization of the $J_{\mathrm{eff}}=1/2$ state


title:
Bertotti-Robinson solutions of D=5 Einstein-Maxwell-Chern-Simons-Lambda
  theory

abstract:
  We present a series of new solutions in five-dimensional
Einstein-Maxwell-Chern-Simons theory with an arbitrary Chern-Simons coupling
$\gamma$ and a cosmological constant $\Lambda$. For general $\gamma$ and
$\Lambda$ we give various generalizations of the Bertotti-Robinson solutions
supported by electric and magnetic fluxes, some of which presumably describe
the near-horizon regions of black strings or black rings. Among them there is a
solution which could apply to the horizon of a topological AdS black ring in
gauged minimal supergravity. Others are horizonless and geodesically complete.
We also construct extremal asymptotically flat multi-string solutions for
$\Lambda=0$ and arbitrary $\gamma$.


title: Multiple mean motion resonances in the HR 8799 planetary system

abstract:
  HR 8799 is a nearby star hosting at least four ~10 Jovian mass planets in
wide orbits up to ~70au, detected through the direct, high-contrast infrared
imaging. Large companions and debris disks reported interior to ~10au, and
exterior to ~100au indicate massive protoplanetary disc in the past. The
dynamical state of the HR 8799 system is not yet fully resolved, due to limited
astrometric data covering tiny orbital arcs. We construct a new, orbital model
of the HR 8799 system, assuming rapid migration of the planets after their
formation in wider orbits. We found that the HR 8799 planets are likely
involved in double Laplace resonance, 1e:2d:4c:8b MMR. Quasi-circular planetary
orbits are coplanar with the stellar equator and inclined by ~25 degrees to the
sky plane. This best-fit orbital configuration matches astrometry, debris disk
models, and mass estimates from cooling models. The multiple MMR is stable for
the age of the star ~160Myr, for at least 1 Gyr unless significant
perturbations to the N-body dynamics are present. We predict four
configurations with the fifth hypothetical innermost planet HR 8799f in ~9.7au,
or ~7.5au orbit, extending the MMR chain to triple Laplace resonance
1f:2e:4d:8c:16b MMR or to the 1f:3e:6d:12c:24b MMR, respectively. Our findings
may establish strong boundary conditions for the system formation and its early
history.