title:
Spatial Distribution of Nucleosynthesis Products in Cassiopeia A:
  Comparison Between Observations and 3D Explosion Models

abstract:
  We examine observed heavy element abundances in the Cassiopeia A supernova
remnant as a constraint on the nature of the Cas A supernova. We compare bulk
abundances from 1D and 3D explosion models and spatial distribution of elements
in 3D models with those derived from X-ray observations. We also examine the
cospatial production of 26Al with other species. We find that the most reliable
indicator of the presence of 26Al in unmixed ejecta is a very low S/Si ratio
(~0.05). Production of N in O/S/Si-rich regions is also indicative. The
biologically important element P is produced at its highest abundance in the
same regions. Proxies should be detectable in supernova ejecta with high
spatial resolution multiwavelength observations.


title:
Low Energy Constants of Chiral Perturbation Theory from the Instanton
  Vacuum

abstract:
  In the framework of the instanton vacuum model we make expansion over the
current mass $m$ and number of colors $N_c$ and evaluate ${\cal O}(1/N_c, m,
m/N_c, m \ln m/N_c)$-corrections to the dynamical quark mass $M$, the quark
condensate $<\bar qq>$, the pion mass $M_\pi$ and decay constant $F_\pi$. We
found the SU(2) $\chi$PT low-energy constants $\bar l_3, \bar l_4$ in a good
correspondence with the phenomenology and lattice calculations.


title:
Green-Schwarz superstring action for (p,q)-strings from a wrapped
  supermembrane on a 2-torus

abstract:
  We consider a wrapped supermembrane around non-trivial two cycles of a
2-torus. We examine the double dimensional reduction and the T-dual
transformation to deduce Green-Schwarz type IIB superstring action for
(p,q)-strings directly from the wrapped supermembrane on the 2-torus. The
resulting action has the couplings with both the NSNS- and the RR-background
fields and has the tension of the (p,q)-string.


title: Complete nucleosynthesis calculations for low-mass stars from NuGrid

abstract:
  Many nucleosynthesis and mixing processes of low-mass stars as they evolve
from the Main Sequence to the thermal-pulse Asymptotic Giant Branch phase
(TP-AGB) are well understood (although of course important physics components,
e.g. rotation, magnetic fields, gravity wave mixing, remain poorly known).
Nevertheless, in the last years presolar grain measurements with high
resolution have presented new puzzling problems and strong constraints on
nucleosynthesis processes in stars. The goal of the NuGrid collaboration is to
present uniform yields for a large range of masses and metallicities, including
low$-$mass stars and massive stars and their explosions. Here we present the
first calculations of stellar evolution and high-resolution, post-processing
simulations of an AGB star with an initial mass of 2 M_sun and solar-like
metallicity (Z=0.01), based on the post-processing code PPN. In particular, we
analyze the formation and evolution of the radiative 13C-pocket between the
17th TP and the 18th TP. The s-process nucleosynthesis profile of a sample of
heavy isotopes is also discussed, before the next convective TP occurrence.


title:
Proximity-driven source of highly spin-polarized ac current on the basis
  of superconductor/weak ferromagnet/superconductor voltage-biased Josephson
  junction

abstract:
  We theoretically investigate an opportunity to implement a source of highly
spin-polarized ac current on the basis of superconductor/weak
ferromagnet/superconductor (SFS) voltage-biased junction in the regime of
essential proximity effect and calculate the current flowing through the probe
electrode tunnel coupled to the ferromagnetic interlayer region. It is shown
that while the polarization of the dc current component is generally small in
case of weak exchange field of the ferromagnet, there is an ac component of the
current in the system. This ac current is highly spin-polarized and entirely
originated from the non-equilibrium proximity effect in the interlayer. The
frequency of the current is controlled by the voltage applied to SFS junction.
We discuss a possibility to obtain a source of coherent ac currents with a
certain phase shift between them by tunnel coupling two probe electrodes at
different locations of the interlayer region.


title: Roberge-Weiss phase transitions and extended Z3 symmetry

abstract:
  Using the Polyakov extended Nambu-Jona-Lasinio (PNJL) model with imaginary
chemical potential, the relation between the Roberge-Weiss (RW) phase
transition and the extended Z3 symmetry is studied. At low temperature, there
is approximate continuous symmetry under the phase transformation of the
Polyakov loop with the shift of the imaginary chemical potential. Due to this
continuous symmetry, the Polyakov loop can oscillate smoothly as the imaginary
chemical potential increases. At high temperature, this continuous symmetry is
broken to an exact discrete symmetry, the extended Z3 symmetry, and the
Polyakov loop can not oscillate smoothly. This symmetry breaking of the
continuous symmetry causes a discontinuity of the Polyakov loop. That is the RW
phase transition.


title: Temporary Grand Unified Theory in Unphysical World

abstract:
  We construct grand unified models on an orbifold based on unphysical grand
unification. The reduction to the standard model or its supersymmetric one is
carried out using a variant of Parisi-Sourlas mechanism and nontrivial $Z_2$
parity assignment.


title: Quantum Crossing Symmetry as Heart of Ghost Imaging

abstract:
  In this paper it is shown that the key to understanding the ghost imaging
mystery are the crossing symmetric photon reactions in the nonlinear media.
Then, an intuitive mechanism for the description of the ghost imaging in terms
of the quantum mirror (QM) is presented. Moreover, we prove that the ghost
imaging laws depend only on the energy-momentum conservation and not on the
photons entanglement.


title: Bit storage by $360^\circ$ domain walls in ferromagnetic nanorings

abstract:
  We propose a design for the magnetic memory cell which allows an efficient
storage, recording, and readout of information on the basis of thin film
ferromagnetic nanorings. The information bit is represented by the polarity of
a stable 360$^\circ$ domain wall introduced into the ring. Switching between
the two magnetization states is achieved by the current applied to a wire
passing through the ring, whereby the $360^\circ$ domain wall splits into two
charged $180^\circ$ walls, which then move to the opposite extreme of the ring
to recombine into a $360^\circ$ wall of the opposite polarity.


title: Three-dimensional physics and the pressure of hot QCD

abstract:
  We update Monte Carlo simulations of the three-dimensional SU(3) + adjoint
Higgs theory, by extrapolating carefully to the infinite volume and continuum
limits, in order to estimate the contribution of the infrared modes to the
pressure of hot QCD. The sum of infrared contributions beyond the known 4-loop
order turns out to be a smooth function, of a reasonable magnitude and specific
sign. Unfortunately, adding this function to the known 4-loop terms does not
improve the match to four-dimensional lattice data, in spite of the fact that
other quantities, such as correlation lengths, spatial string tension, or quark
number susceptibilities, work well within the same setup. We outline possible
ways to reduce the mismatch.


title: Rapid Formation of Icy Super-Earths and the Cores of Gas Giant Planets

abstract:
  We describe a coagulation model that leads to the rapid formation of
super-Earths and the cores of gas giant planets. Interaction of collision
fragments with the gaseous disk is the crucial element of this model. The gas
entrains small collision fragments, which rapidly settle to the disk midplane.
Protoplanets accrete the fragments and grow to masses of at least 1 Earth mass
in roughly 1 Myr. Our model explains the mass distribution of planets in the
Solar System and predicts that super-Earths form more frequently than gas
giants in low mass disks.


title: Gotzmann lexsegment ideals

abstract:
  In this paper we characterize the componentwise lexsegment ideals which are
componentwise linear and the lexsegment ideals generated in one degree which
are Gotzmann.


title: What is the fate of a black hole embedded in an expanding universe?

abstract:
  Within a large class of exact solutions of the Einstein equations describing
a black hole embedded in a Friedmann universe it is shown that, under certain
assumptions, only those with comoving Hawking-Hayward quasi-local mass are
generic, in the sense that they are late-time attractors.


title:
Thermal Hall Conductivity as a Probe of Gap Structure in Multi-band
  Superconductors: The Case of $\rm Ba_{1-x}K_xFe_2As_2$

abstract:
  The sign and profile of the thermal Hall conductivity $\kappa_{xy}$ gives
important insights into the gap structure of multi-band superconductors. With
this perspective, we have investigated $\kappa_{xy}$ and the thermal
conductivity $\kappa_{xx}$ in $\rm Ba_{1-x}K_xFe_2As_2$ which display large
peak anomalies in the superconducting state. The anomalies imply that a large
hole-like quasiparticle (qp) population exists below the critical temperature
$T_c$. We show that the qp mean-free-path inferred from $\kappa_{xx}$
reproduces the observed anomaly in $\kappa_{xy}$, providing a consistent
estimate of a large qp population. Further, we demonstrate that the hole-like
signal is consistent with a theoretical scenario where despite potentially
large gap variations on the electron pockets, the minimal homogeneous gap of
the superconducting phase resides at a hole pocket. Implications for probing
the gap structure in the broader class of pnictide superconductors are
discussed.


title:
Generalized Landau-Lifshitz systems and Lie algebras associated with
  higher genus curves

abstract:
  The Wahlquist-Estabrook prolongation method allows to obtain for some PDEs a
Lie algebra that is responsible for Lax pairs and Backlund transformations of
certain type. We study the Wahlquist-Estabrook algebra of the n-dimensional
generalization of the Landau-Lifshitz equation and construct an epimorphism
from this algebra onto an infinite-dimensional quasigraded Lie algebra L(n) of
certain matrix-valued functions on an algebraic curve of genus 1+(n-3)2^{n-2}.
For n=3,4,5 we prove that the Wahlquist-Estabrook algebra is isomorphic to the
direct sum of L(n) and a 2-dimensional abelian Lie algebra. Using these
results, for any n a new family of Miura type transformations (differential
substitutions) parametrized by points of the above mentioned curve is
constructed. As a by-product, we obtain a representation of L(n) in terms of a
finite number of generators and relations, which may be of independent
interest.


title: Gauge fields, ripples and wrinkles in graphene layers

abstract:
  We analyze elastic deformations of graphene sheets which lead to effective
gauge fields acting on the charge carriers. Corrugations in the substrate
induce stresses, which, in turn, can give rise to mechanical instabilities and
the formation of wrinkles. Similar effects may take place in suspended graphene
samples under tension.


title: New supersymmetric quartet of nuclei in the A=190 mass region

abstract:
  We present evidence for a new supersymmetric quartet in the A=190 region of
the nuclear mass table. New experimental information on transfer and neutron
capture reactions to the odd-odd nucleaus 194 Ir strongly suggests the
existence of a new supersymmetric quartet, consisting of the 192,193 Os and
193,194 Ir nuclei. We make explicit predictions for the odd-neutron nucleus 193
Os, and suggest that its spectroscopic properties be measured in dedicated
experiments.


title:
Fast and Quality-Guaranteed Data Streaming in Resource-Constrained
  Sensor Networks

abstract:
  In many emerging applications, data streams are monitored in a network
environment. Due to limited communication bandwidth and other resource
constraints, a critical and practical demand is to online compress data streams
continuously with quality guarantee. Although many data compression and digital
signal processing methods have been developed to reduce data volume, their
super-linear time and more-than-constant space complexity prevents them from
being applied directly on data streams, particularly over resource-constrained
sensor networks. In this paper, we tackle the problem of online quality
guaranteed compression of data streams using fast linear approximation (i.e.,
using line segments to approximate a time series). Technically, we address two
versions of the problem which explore quality guarantees in different forms. We
develop online algorithms with linear time complexity and constant cost in
space. Our algorithms are optimal in the sense they generate the minimum number
of segments that approximate a time series with the required quality guarantee.
To meet the resource constraints in sensor networks, we also develop a fast
algorithm which creates connecting segments with very simple computation. The
low cost nature of our methods leads to a unique edge on the applications of
massive and fast streaming environment, low bandwidth networks, and heavily
constrained nodes in computational power. We implement and evaluate our methods
in the application of an acoustic wireless sensor network.


title:
Massless scalar free Field in 1+1 dimensions, II: Net Cohomology and
  Completeness of Superselection Sectors

abstract:
  As an application of Roberts' cohomology (net cohomology), we prove the
completeness of the DHR sectors of the local observables of the model in the
title, detailed in [8]. This result is achieved via the triviality of the net
1-cohomology, with values in the local fields, enhancing the Roberts' methods
to the case of anyonic Weyl nets, not satisfying the split property. We take
advantage of using different causal index sets for the nets involved. The
presence of anyonic commutation relations is treated introducing the notion of
nets graded by a generic group, and the related properties of graded locality
and graded duality. As a further result, we obtain the description of twisted
and untwisted sectors of the model as two symmetric subcategories of a
W*-braided category, whose objects are the same as the dual category of the
compact Abelian group of the gauge symmetry. The work also furnish some hints
for the analysis of the sector structure of generic models on different
spacetimes.


title:
Oscillating red giants in the CoRoT exo-field: Asteroseismic mass and
  radius determination

abstract:
  Context. Observations and analysis of solar-type oscillations in red-giant
stars is an emerging aspect of asteroseismic analysis with a number of open
questions yet to be explored. Although stochastic oscillations have previously
been detected in red giants from both radial velocity and photometric
measurements, those data were either too short or had sampling that was not
complete enough to perform a detailed data analysis of the variability. The
quality and quantity of photometric data as provided by the CoRoT satellite is
necessary to provide a breakthrough in observing p-mode oscillations in red
giants. We have analyzed continuous photometric time-series of about 11 400
relatively faint stars obtained in the exofield of CoRoT during the first 150
days long-run campaign from May to October 2007. We find several hundred stars
showing a clear power excess in a frequency and amplitude range expected for
red-giant pulsators. In this paper we present first results on a sub-sample of
these stars. Aims. Knowing reliable fundamental parameters like mass and radius
is essential for detailed asteroseismic studies of red-giant stars. As the
CoRoT exofield targets are relatively faint (11-16 mag) there are no (or only
weak) constraints on the star's location in the H-R diagram. We therefore aim
to extract information about such fundamental parameters solely from the
available time series. Methods. We model the convective background noise and
the power excess hump due to pulsation with a global model fit and deduce
reliable estimates for the stellar mass and radius from scaling relations for
the frequency of maximum oscillation power and the characteristic frequency
separation.


title:
Superconducting phase transitions in frustrated Josephson-junction
  arrays on a dice lattice

abstract:
  Transport measurements are carried out on dice Josephson-junction arrays with
the frustration index $f=1/3$ and 1/2 which possess, within the limit of the
$XY$ model, an accidental degeneracy of the ground states as a consequence of
the formation of zero-energy domain walls. The measurements demonstrate that
both the systems undergo a phase transition to a superconducting vortex-ordered
state at considerably high temperatures. The experimental findings are in
apparent contradiction with the theoretical expectation that frustration
effects in the $f=1/3$ system are particularly strong enough to suppress a
vortex-ordering transition down to near zero temperature. The data for $f=1/2$
are more consistent with theoretical evaluations. The agreement between the
experiments and the Monte Carlo simulations of a $XY$ model for $f=1/3$
suggests that the order-from-disorder mechanism for the removal of an
accidental degeneracy may still be effective in the $f=1/3$ system. The
transport data also reveal that the dice arrays with zero-energy domain walls
experience a much slower critical relaxation than other frustrated arrays only
with finite-energy walls.


title: Observational constraints on thawing quintessence models

abstract:
  We use a dynamical systems approach to study thawing quintessence models,
using a multi-parameter extension of the exponential potential which can
approximate the form of typical thawing potentials. We impose observational
constraints using a compilation of current data, and forecast the tightening of
constraints expected from future dark energy surveys, as well as discussing the
relation of our results to analytical constraints already in the literature.


title:
Convergence rates of posterior distributions for observations without
  the iid structure

abstract:
  The classical condition on the existence of uniformly exponentially
consistent tests for testing the true density against the complement of its
arbitrary neighborhood has been widely adopted in study of asymptotics of
Bayesian nonparametric procedures. Because we follow a Bayesian approach, it
seems to be more natural to explore alternative and appropriate conditions
which incorporate the prior distribution. In this paper we supply a new
prior-dependent integration condition to establish general posterior
convergence rate theorems for observations which may not be independent and
identically distributed. The posterior convergence rates for such observations
have recently studied by Ghosal and van der Vaart \cite{ghv1}. We moreover
adopt the Hausdorff $\alpha$-entropy given by Xing and Ranneby
\cite{xir1}\cite{xi1}, which is also prior-dependent and smaller than the
widely used metric entropies. These lead to extensions of several existing
theorems. In particular, we establish a posterior convergence rate theorem for
general Markov processes and as its application we improve on the currently
known posterior rate of convergence for a nonlinear autoregressive model.


title: Mathematics underlying the 2008 financial crisis, and a possible remedy

abstract:
  This paper has been withdrawn by the authors, because it has been made
obsolete by the detailed expositions in our papers in arXiv:0812.4885 (the
mathematics part) and arXiv:0812.4737 (the economics part).


title: Entanglement entropy and the determination of an unknown quantum state

abstract:
  An initial unknown quantum state can be determined with a single measurement
apparatus by letting it interact with an auxiliary, "Ancilla", system as
proposed by Allahverdyan, Balian and Nieuwenhuizen [Phys. Rev. Lett. 92, 120402
(2004)]. In the case of two qubits, this procedure allows to reconstruct the
initial state of the qubit of interest S by measuring three commuting
observables and therefore by means of a single apparatus, for the total system
S + A at a later time. The determinant of the matrix of the linear
transformation connecting the measurements of three commuting observables at
time t > 0 to the components of the polarization vector of S at time t = 0 is
used as an indicator of the reconstructability of the initial state of the
system S. We show that a connection between the entanglement entropy of the
total system S + A and such a determinant exists, and that for a pure state a
vanishing entanglement individuates, without a need for any measurement, those
intervals of time for which the reconstruction procedure is least efficient.
This property remains valid for a generic dimension of S. In the case of a
mixed state this connection is lost.


title: Clifford indices for vector bundles on curves

abstract:
  For smooth projective curves the Clifford index is an important invariant
which provides a bound for the dimension of the space of sections of a line
bundle. This is the first step in distinguishing curves of the same genus. In
this paper we generalise this to introduce Clifford indices for semistable
vector bundles on curves. We study these invariants, giving some basic
properties and carrying out some computations for small ranks and for general
and some special curves. For curves whose classical Clifford index is two, we
compute all values of our new Clifford indices.


title:
The Good, the Bad, and the Ugly: three different approaches to break
  their watermarking system

abstract:
  The Good is Blondie, a wandering gunman with a strong personal sense of
honor. The Bad is Angel Eyes, a sadistic hitman who always hits his mark. The
Ugly is Tuco, a Mexican bandit who's always only looking out for himself.
Against the backdrop of the BOWS contest, they search for a watermark in gold
buried in three images. Each knows only a portion of the gold's exact location,
so for the moment they're dependent on each other. However, none are
particularly inclined to share...


title: Precision Electroweak Measurements and Constraints on the Standard Model

abstract:
  This note presents constraints on Standard Model parameters using published
and preliminary precision electroweak results measured at the electron-positron
colliders LEP and SLC. The results are compared with precise electroweak
measurements from other experiments, notably CDF and D{\O}at the Tevatron.
Constraints on the input parameters of the Standard Model are derived from the
results obtained in high-$Q^2$ interactions, and used to predict results in
low-$Q^2$ experiments, such as atomic parity violation, M{\o}ller scattering,
and neutrino-nucleon scattering. The main changes with respect to the
experimental results presented in 2007 are new combinations of results on the
W-boson mass and width and the mass of the top quark.


title: Lepton Flavor Model from Delta(54) Symmetry

abstract:
  We present the lepton flavor model with $\Delta (54)$, which appears
typically in heterotic string models on the $T^2/Z_3$ orbifold. Our model
reproduces the tri-bimaximal mixing in the parameter region around degenerate
neutrino masses or two massless neutrinos. We predict the deviation from the
tri-bimaximal mixing by putting the experimental data of neutrino masses in the
normal hierarchy of neutrino masses. The upper bound of $\sin^2\theta_{13}$ is
0.01. There is the strong correlation between $\theta_{23}$ and $\theta_{13}$.
Unless $\theta_{23}$ is deviated from the maximal mixing considerably,
$\theta_{13}$ remains to be tiny.


title: Six Puzzles for LCDM Cosmology

abstract:
  The LCDM cosmological model is a well defined, simple and predictive model
which is consistent with the majority of current cosmological observations.
Despite of these successes there are specific cosmological observations which
differ from the predictions of LCDM at a level of 2\sigma or higher. These
observations include the following: 1. Large Scale Velocity Flows (LCDM
predicts significantly smaller amplitude and scale of flows than what
observations indicate), 2. Brightness of Type Ia Supernovae (SnIa) at High
Redshift z (LCDM predicts fainter SnIa at High z), 3. Emptiness of Voids (LCDM
predicts more dwarf or irregular galaxies in voids than observed), 4. Profiles
of Cluster Haloes (LCDM predicts shallow low concentration and density profiles
in contrast to observations which indicate denser high concentration cluster
haloes) 5. Profiles of Galaxy Haloes (LCDM predicts halo mass profiles with
cuspy cores and low outer density while lensing and dynamical observations
indicate a central core of constant density and a flattish high dark mass
density outer profile), 6. Sizable Population of Disk Galaxies (LCDM predicts a
smaller fraction of disk galaxies due to recent mergers expected to disrupt
cold rotationally supported disks). Even though the origin of some of the above
challenges may be astrophysical or related to dark matter properties, it should
be stressed that even on galactic and cluster scales, the effects of dark
energy on the equilibrium and stability of astrophysical systems are not
negligible and they may play a key role in the resolution of the above puzzles.
Here, I briefly review these six challenges of LCDM and discuss the possible
dark energy properties required for their resolution.


title: Unconditional bases and strictly convex dual renormings

abstract:
  We present equivalent conditions for a space $X$ with an unconditional basis
to admit an equivalent norm with a strictly convex dual norm.


title: The nature of p-modes and granulation in HD 49933 observed by CoRoT

abstract:
  Context: Recent observations of HD49933 by the space-photometric mission
CoRoT provide photometric evidence of solar type oscillations in a star other
than our Sun. The first published reduction, analysis, and interpretation of
the CoRoT data yielded a spectrum of p-modes with l = 0, 1, and 2. Aims: We
present our own analysis of the CoRoT data in an attempt to compare the
detected pulsation modes with eigenfrequencies of models that are consistent
with the observed luminosity and surface temperature. Methods: We used the
Gruberbauer et al. frequency set derived based on a more conservative Bayesian
analysis with ignorance priors and fit models from a dense grid of model
spectra. We also introduce a Bayesian approach to searching and quantifying the
best model fits to the observed oscillation spectra. Results: We identify 26
frequencies as radial and dipolar modes. Our best fitting model has solar
composition and coincides within the error box with the spectroscopically
determined position of HD49933 in the H-R diagram. We also show that
lower-than-solar Z models have a lower probability of matching the observations
than the solar metallicity models. To quantify the effect of the deficiencies
in modeling the stellar surface layers in our analysis, we compare adiabatic
and nonadiabatic model fits and find that the latter reproduces the observed
frequencies better.


title:
On the Time Average of the Autocorrelation Function in Hamiltonian
  Dynamics

abstract:
  Rigorous lower bound on the time-average of the autocorrelation function of
an arbitrary L^1 observable is proven in terms of conserved quantities and
ergodic decompositions of the Hamiltonian dynamics. Improvements with respect
to the bounds given by Mazur and Suzuki are discussed.

categories: math.DS cond-mat.stat-mech math-ph math.MP


title: Single-top Cross Section Measurements at ATLAS

abstract:
  The single-top production cross section is one third that of the top-pair
production cross section at the LHC. During a year of data-taking, assuming an
average luminosity of 10^33 cm-2 s-1 and a CMS energy of 14 TeV, the
determination of the major contributions to the total single-top cross section
should be achievable. Comparisons between the measured cross sections and the
theoretical predictions will provide a crucial test of the standard model.
These measurements should also lead to the first direct measurement of |V_tb|,
with a precision at the level of a few percent. In addition, they will probe
for new physics via the search for evidence of anomalous couplings to the top
quark and the measurements of additional bosonic contributions to single-top
production. Methods developed to optimize the selection of single-top events in
the three production channels are presented and the potential for the cross
section measurements with 1 fb-1 and 30 fb-1 of integrated luminosity is
established.


title: CP-Violation in Low-Energy Photon-Photon Interactions

abstract:
  CP-violation in the loop-mediated photon-photon interactions would modify the
birefringence of the quantum vacuum. We discuss the implications of this effect
on the PVLAS-Phase II experiment, in which a time-dependent magnetic field is
modulated. We show that the violation of CP would imply the existence of
characteristic Fourier components, in the intensity spectrum of the outgoing
wave. In order to estimate the magnitude of this effect within the Standard
Model, we use chiral perturbation theory to compute the theta-term contribution
to the coefficient of the leading CP-odd vertex, in the low-energy effective
field theory for photon dynamics.


title: Sur les formules locales de l'indice

abstract:
  We review some facts about bivariant Chern characters in Noncommutative
Geometry and anomaly formulas in Quantum Field Theory.


title: Bouvier's conjecture

abstract:
  This paper deals with Bouvier's conjecture which sustains that
finite-dimensional non-Noetherian Krull domains need not be Jaffard


title:
Environmental Effect on the UV Optical Absorption of Single-Walled
  Carbon Nanotubes

abstract:
  We studied optical absorption of single-walled carbon nanotubes by varying
the dielectric environment. For the two different components of the broad UV
absorption feature conventionally referred to as the pi-plasmon, we find that
the component at 5.0 - 5.3 eV exhibits remarkable spectral changes, based on
which we attribute this to a dipolar radial surface plasmon. However, the
component at ~4.5 eV remains unchanged, raising a fundamental question as to
its conventional attribution. We discuss its relation with the absorption
feature at ~4.5 eV in graphite arising from an interband transition.


title: t-Class semigroups of Noetherian domains

abstract:
  The t-class semigroup of an integral domain is the semigroup of fractional
t-ideals modulo its subsemigroup of nonzero principal ideals with the operation
induced by ideal t-multiplication. This paper investigates ring-theoretic
properties of a Noetherian domain that reflect reciprocally in the Clifford or
Boolean property of its t-class semigroup.


title: Stellar population analysis on local infrared-selected galaxies

abstract:
  To study the stellar population of local infrared galaxies, which contain
star-forming galaxies, composite galaxies, LINERs, and Seyfert 2s. We also want
to find whether infrared luminosity and spectral class have any effects on
their stellar populations. The sample galaxies are selected from the main
galaxy sample of SDSS-DR4 and then cross-correlated with the IRAS-PSCz catalog.
We fit our spectra (stellar absorption lines and continua) using the spectral
synthesis code STARLIGHT on the base of the templates of Simple Stellar
Population and the spectra of star clusters.Among the 4 spectral classes,
LINERs present the oldest stellar populations, and the other 3 sub-samples all
present substantial young and intermediate age populations and very few old
populations. The importance of young populations decreases from star-forming,
composite, Seyfert 2 to LINER. As to different infrared luminosity bins, ULIGs
& LIGs (log($L_{IR}/L_{\odot})\geq$11) present younger populations than
starbursts and normal galaxies. However, the dominant contributors to mass are
old populations in all sample galaxies. The fittings by using the spectra of
star clusters with different ages and metallicities as templates also give
consistent results. The dominated populations in star-forming and composite
galaxies are those with metallicity $Z=0.2Z_\odot$, while LINERs and Seyfert 2s
are more metal-rich. The normal galaxies are more metal-rich than the ULIGs &
LIGs and starbursts for the star-forming galaxies within different infrared
luminosity bins. Additionally, we also compare some synthesis results with
other parameters obtained from the MPA/JHU catalog.


title:
Information Transferring Ability of the Different Phases of a finite XXZ
  Spin Chain

abstract:
  We study the transmission of both classical or quantum information through
all the phases of a finite XXZ spin chain. This characterizes the merit of the
different phases in terms of their ability to act as a quantum wire. As far as
quantum information is concerned, we need only consider the transmission of
entanglement as the direct transmission of a quantum state is equivalent. The
isotropic anti-ferromagnetic spin chain is found to be the optimal point of the
phase diagram for the transmission of quantum entanglement when one considers
both the amount of transmitted entanglement, as well as the velocity with which
it is transmitted. But this optimal point in the phase diagram moves to the
Neel phase when decoherence or thermal fluctuations are taken to account. This
chain may also be able to transfer classical information even when, due to a
large magnitude of the noise, quantum information is not transmitted at all.
For a certain range of anisotropies of the model, a curious feature is found in
the flow of quantum information inside the chain, namely, a hopping mode of
entanglement transfer which skips the odd numbered sites. Our predictions will
potentially be testable in several physical systems.


title: Hubbard model calculations of phase separation in optical lattices

abstract:
  Antiferromagnetic, Mott insulator, d-wave and gossamer superfluid phases are
calculated for 2D square lattices from the extended Hubbard (t-J-U) model using
the Gutzwiller projection method and renormalized mean field theory. Phase
separation between antiferromagnetic and d-wave superfluid phases is found near
half filling when the on-site repulsion exceeds $U\ga7.3t$, and coincides with
a first order transition in the double occupancy. Phase separation is thus
predicted for 2D optical lattices with ultracold Fermi atoms whereas it is
inhibited in cuprates by Coulomb frustration which instead may lead to stripes.
In a confined optical lattice the resulting density distribution is
discontinuous an with extended Mott plateau which enhances the
antiferromagnetic phase but suppresses the superfluid phase. Observation of
Mott insulator, antiferromagnetic, stripe and superfluid phases in density and
momentum distributions and correlations is discussed.


title:
Informed stego-systems in active warden context: statistical
  undetectability and capacity

abstract:
  Several authors have studied stego-systems based on Costa scheme, but just a
few ones gave both theoretical and experimental justifications of these schemes
performance in an active warden context. We provide in this paper a
steganographic and comparative study of three informed stego-systems in active
warden context: scalar Costa scheme, trellis-coded quantization and spread
transform scalar Costa scheme. By leading on analytical formulations and on
experimental evaluations, we show the advantages and limits of each scheme in
term of statistical undetectability and capacity in the case of active warden.
Such as the undetectability is given by the distance between the stego-signal
and the cover distance. It is measured by the Kullback-Leibler distance.


title:
Non-Gaussianity in Cosmic Microwave Background Temperature Fluctuations
  from Cosmic (Super-)Strings

abstract:
  We compute analytically the small-scale temperature fluctuations of the
cosmic microwave background from cosmic (super-)strings and study the
dependence on the string intercommuting probability $P$. We develop an
analytical model which describes the evolution of a string network and
calculate the numbers of string segments and kinks in a horizon volume. Then we
derive the probability distribution function (pdf) which takes account of
finite angular resolution of observation. The resultant pdf consists of a
Gaussian part due to frequent scatterings by long string segments and a
non-Gaussian tail due to close encounters with kinks. The dispersion of the
Gaussian part is reasonably consistent with that obtained by numerical
simulations by Fraisse et al.. On the other hand, the non-Gaussian tail
contains two phenomenological parameters which are determined by comparison
with the numerical results for P=1. Extrapolating the pdf to the cases with
$P<1$, we predict that the non-Gaussian feature is suppressed for small $P$.


title: Mapping Images with the Coherence Length Diagrams

abstract:
  Statistical pattern recognition methods based on the Coherence Length Diagram
(CLD) have been proposed for medical image analyses, such as quantitative
characterisation of human skin textures, and for polarized light microscopy of
liquid crystal textures. Further investigations are made on image maps
originated from such diagram and some examples related to irregularity of
microstructures are shown.


title: Trellis-coded quantization for public-key steganography

abstract:
  This paper deals with public-key steganography in the presence of a passive
warden. The aim is to hide secret messages within cover-documents without
making the warden suspicious, and without any preliminar secret key sharing.
Whereas a practical attempt has been already done to provide a solution to this
problem, it suffers of poor flexibility (since embedding and decoding steps
highly depend on cover-signals statistics) and of little capacity compared to
recent data hiding techniques. Using the same framework, this paper explores
the use of trellis-coded quantization techniques (TCQ and turbo TCQ) to design
a more efficient public-key scheme. Experiments on audio signals show great
improvements considering Cachin's security criterion.


title: Analog of Electroweak Model for Contracted Gauge Group

abstract:
  The limiting case of the bosonic part of the standard Electroweak Model,
which correspond to the contracted gauge group $ SU(2;j)\times U(1)$ is
discussed. The Higgs boson, Z-boson and electromagnetic fields become an
external ones with respect to the W-bosons fields. The W-bosons fields do not
effect on these external fields. The masses of the all particles of the
Electroweak Model remain the same under contraction.


title:
Information-theoretic resolution of perceptual WSS watermarking of non
  i.i.d. Gaussian signals

abstract:
  The theoretical foundations of data hiding have been revealed by formulating
the problem as message communication over a noisy channel. We revisit the
problem in light of a more general characterization of the watermark channel
and of weighted distortion measures. Considering spread spectrum based
information hiding, we release the usual assumption of an i.i.d. cover signal.
The game-theoretic resolution of the problem reveals a generalized
characterization of optimum attacks. The paper then derives closed-form
expressions for the different parameters exhibiting a practical embedding and
extraction technique.


title: Gromov-Witten invariants of toric Calabi-Yau threefolds

abstract:
  Based on the large N duality relating topological string theory on Calabi-Yau
3-folds and Chern-Simons theory on 3-manifolds, M. Aganagic, A. Klemm, M.
Marino and C. Vafa proposed the topological vertex (hep-th/0305132), an
algorithm on computing Gromov-Witten invariants in all genera of any
non-singular toric Calabi-Yau 3-fold. In this expository article, we describe
the mathematical theory of the topological vertex developed by J. Li, K. Liu,
J. Zhou, and the author (math/0408426).


title: Divided power structures and chain complexes

abstract:
  We interpret divided power structures on the homotopy groups of simplicial
commutative rings as having a counterpart in divided power structures on chain
complexes coming from a non-standard symmetric monoidal structure.


title:
2.5-dimensional solution of the advective accretion disk: A self-similar
  approach

abstract:
  We provide a 2.5-dimensional solution to a complete set of viscous
hydrodynamical equations describing accretion-induced outflow and then
plausible jet around black holes/compact objects. We prescribe a
self-consistent advective disk-outflow coupling model, which explicitly
includes the information of vertical flux. Inter-connecting dynamics of
inflow-outflow system essentially upholds the conservation laws. We provide a
set of analytical family of solutions through the self-similar approach. The
flow parameters of the disk-outflow system depend strongly on viscosity
parameter \alpha and cooling factor f.


title: Comparing Measures of Sparsity

abstract:
  Sparsity of representations of signals has been shown to be a key concept of
fundamental importance in fields such as blind source separation, compression,
sampling and signal analysis. The aim of this paper is to compare several
commonlyused sparsity measures based on intuitive attributes. Intuitively, a
sparse representation is one in which a small number of coefficients contain a
large proportion of the energy. In this paper six properties are discussed:
(Robin Hood, Scaling, Rising Tide, Cloning, Bill Gates and Babies), each of
which a sparsity measure should have. The main contributions of this paper are
the proofs and the associated summary table which classify commonly-used
sparsity measures based on whether or not they satisfy these six propositions
and the corresponding proofs. Only one of these measures satisfies all six: The
Gini Index. measures based on whether or not they satisfy these six
propositions and the corresponding proofs. Only one of these measures satisfies
all six: The Gini Index.


title:
Swift follow-up observations of 17 INTEGRAL sources of uncertain or
  unknown nature

abstract:
  (abridged) We analysed data from observations of 17 INTEGRAL sources made
with the Swift satellite. We refine the position of the hard X-ray sources to
an accuracy of a few arcsec. We then browsed the online catalogs (e.g., NED,
SIMBAD, 2MASS, 2MASX, USNO) to search for counterparts at other wavelengths. We
also made use of the X-ray spectral parameters to try to identify the nature of
those sources. We provide the X-ray position with arcsec accuracy, identify
possible infrared and optical counterparts (when found), give the magnitudes in
those bands and in the optical and UV as seen with the Swift/UVOT telescope
when observations are available. We confirm the previously suggested
associations and source types for IGR J03532-6829, J05346-5759, J10101-5654,
J13000+2529, J13020-6359, J15479-4529, J18214-1318, and J23206+6431. We
identify
  IGR J09025-6814 as an AGN for the first time, and we suggest that it may be a
Seyfert 2. We suggest that IGR J05319-6601, J16287-5021, J17353-3539 and
J17476-2253 are X-ray binaries, with J05319-6601 being located in the LMC and
the other three possibly being HMXBs in our Galaxy. For IGR J15161-3827 and
J20286+2544, we find several possible X-ray counterparts in the IBIS error
region, and we discuss which, if any, are the likely counterparts. Both are
likely AGNs, although the latter could be a blend of two AGNs. For IGR
J03184-0014 and J19267+1325, we find X-ray sources slightly outside the IBIS
error circle. In the former, we do not favour an association of the Swift and
INTEGRAL source, while it is very likely that IGR J19267+1325 and the Swift
source are the same.


title: Transport coefficients near chiral phase transition

abstract:
  We analyze the transport properties of relativistic fluid composed of
constituent quarks at finite temperature and density. We focus on the shear and
bulk viscosities and study their behavior near chiral phase transition. We
model the constituent quark interactions through the Nambu--Jona Lasinio
Lagrangian. The transport coefficients are calculated within kinetic theory
under relaxation time approximation including in--medium modification of
quasi--particles dispersion relations. We quantify the influence of the order
of chiral phase transition and the critical end point on dissipative phenomena
in such a medium. Considering the changes of shear and bulk viscosities along
the phase boundary we discuss their sensitivity to probe the existence of the
critical end point.


title: Role of microenvironment in the mixed Langmuir-Blodgett films

abstract:
  This paper reports the pi-A isotherms and spectroscopic characteristics of
mixed Langmuir and Langmuir-Blodgett (LB) films of non-amphiphilic carbazole
(CA) molecules mixed with polymethyl methacrylate (PMMA) and stearic acid (SA).
pi-A isotherm studies of mixed monolayer and as well as also the collapse
pressure study of isotherms definitely conclude that CA is incorporated into
PMMA and SA matrices. However CA is stacked in the PMMA/SA chains and forms
microcrystalline aggregates as is evidenced from the scanning electron
micrograph picture. Nature of these aggregated species in the mixed LB films
has been revealed by UV-Vis absorption and fluorescence spectroscopic studies.
The presence of two different kinds of band systems in the fluorescence spectra
of the mixed LB films have been observed. This may be due to the formation of
low dimensional aggregates in the mixed LB films. Intensity distribution of
different band system is highly sensitive to the microenvironment of two
different matrices as well as also on the film thickness


title:
Transport, magnetic, and structural properties of
  La$_{0.7}$Ce$_{0.3}$MnO$_3$ thin films. Evidence for hole-doping

abstract:
  Cerium-doped manganite thin films were grown epitaxially by pulsed laser
deposition at $720 ^\circ$C and oxygen pressure $p_{O_2}=1-25 $Pa and were
subjected to different annealing steps. According to x-ray diffraction (XRD)
data, the formation of CeO$_2$ as a secondary phase could be avoided for
$p_{O_2}\ge 8 $Pa. However, transmission electron microscopy shows the presence
of CeO$_2$ nanoclusters, even in those films which appear to be single phase in
XRD. With O$_2$ annealing, the metal-to-insulator transition temperature
increases, while the saturation magnetization decreases and stays well below
the theoretical value for electron-doped La$_{0.7}$Ce$_{0.3}$MnO$_3$ with mixed
Mn$^{3+}$/Mn$^{2+}$ valences. The same trend is observed with decreasing film
thickness from 100 to 20 nm, indicating a higher oxygen content for thinner
films. Hall measurements on a film which shows a metal-to-insulator transition
clearly reveal holes as dominating charge carriers. Combining data from x-ray
photoemission spectroscopy, for determination of the oxygen content, and x-ray
absorption spectroscopy (XAS), for determination of the hole concentration and
cation valences, we find that with increasing oxygen content the hole
concentration increases and Mn valences are shifted from 2+ to 4+. The
dominating Mn valences in the films are Mn$^{3+}$ and Mn$^{4+}$, and only a
small amount of Mn$^{2+}$ ions can be observed by XAS. Mn$^{2+}$ and Ce$^{4+}$
XAS signals obtained in surface-sensitive total electron yield mode are
strongly reduced in the bulk-sensitive fluorescence mode, which indicates
hole-doping in the bulk for those films which do show a metal-to-insulator
transition.


title: Local dark matter searches with LISA

abstract:
  The drag-free satellites of LISA will maintain the test masses in geodesic
motion over many years with residual accelerations at unprecedented small
levels and time delay interferometry (TDI) will keep track of their
differential positions at level of picometers. This may allow investigations of
fine details of the gravitational field in the Solar System previously
inaccessible. In this spirit, we present the concept of a method to measure
directly the gravitational effect of the density of diffuse Local Dark Matter
(LDM) with a constellation of a few drag-free satellites, by exploiting how
peculiarly it would affect their relative motion. Using as test bed an
idealized LISA with rigid arms, we find that the separation in time between the
test masses is uniquely perturbed by the LDM, so that they acquire a
differential breathing mode. Such a LDM signal is related to the LDM density
within the orbits and has characteristic spectral components, with amplitudes
increasing in time, at various frequencies of the dynamics of the
constellation. This is the relevant result, in that the LDM signal is brought
to non-zero frequencies.


title: From quantum electrodynamics to posets of planar binary trees

abstract:
  This paper is a brief mathematical excursion which starts from quantum
electrodynamics and leads to the Moebius function of the Tamari lattice of
planar binary trees, within the framework of groups of tree-expanded series.
First we recall Brouder's expansion of the photon and the electron Green's
functions on planar binary trees, before and after the renormalization. Then we
recall the structure of Connes and Kreimer's Hopf algebra of renormalization in
the context of planar binary trees, and of their dual group of tree-expanded
series. Finally we show that the Moebius function of the Tamari posets of
planar binary trees gives rise to a particular series in this group.


title: Compact Labelings For Efficient First-Order Model-Checking

abstract:
  We consider graph properties that can be checked from labels, i.e., bit
sequences, of logarithmic length attached to vertices. We prove that there
exists such a labeling for checking a first-order formula with free set
variables in the graphs of every class that is \emph{nicely locally
cwd-decomposable}. This notion generalizes that of a \emph{nicely locally
tree-decomposable} class. The graphs of such classes can be covered by graphs
of bounded \emph{clique-width} with limited overlaps. We also consider such
labelings for \emph{bounded} first-order formulas on graph classes of
\emph{bounded expansion}. Some of these results are extended to counting
queries.


title: Fast rotating Bose-Einstein condensates in an asymmetric trap

abstract:
  We investigate the effect of the anisotropy of a harmonic trap on the
behaviour of a fast rotating Bose-Einstein condensate. This is done in the
framework of the 2D Gross-Pitaevskii equation and requires a symplectic
reduction of the quadratic form defining the energy. This reduction allows us
to simplify the energy on a Bargmann space and study the asymptotics of large
rotational velocity. We characterize two regimes of velocity and anisotropy; in
the first one where the behaviour is similar to the isotropic case, we
construct an upper bound: a hexagonal Abrikosov lattice of vortices, with an
inverted parabola profile. The second regime deals with very large velocities,
a case in which we prove that the ground state does not display vortices in the
bulk, with a 1D limiting problem. In that case, we show that the coarse grained
atomic density behaves like an inverted parabola with large radius in the
deconfined direction but keeps a fixed profile given by a Gaussian in the other
direction. The features of this second regime appear as new phenomena.


title: Utility maximization in incomplete markets with default

abstract:
  We adress the maximization problem of expected utility from terminal wealth.
The special feature of this paper is that we consider a financial market where
the price process of risky assets can have a default time. Using dynamic
programming, we characterize the value function with a backward stochastic
differential equation and the optimal portfolio policies. We separately treat
the cases of exponential, power and logarithmic utility.


title: A Construction of Biorthogonal Wavelets With a Compact Operator

abstract:
  We present a construction of biorthogonal wavelets using a compact operator
which allows to preserve or increase some properties: regularity/vanishing
moments, parity, compact supported. We build then a simple algorithm which
computes new filters.


title:
Prospective Study for Semantic Inter-Media Fusion in Content-Based
  Medical Image Retrieval

abstract:
  One important challenge in modern Content-Based Medical Image Retrieval
(CBMIR) approaches is represented by the semantic gap, related to the
complexity of the medical knowledge. Among the methods that are able to close
this gap in CBMIR, the use of medical thesauri/ontologies has interesting
perspectives due to the possibility of accessing on-line updated relevant
webservices and to extract real-time medical semantic structured information.
The CBMIR approach proposed in this paper uses the Unified Medical Language
System's (UMLS) Metathesaurus to perform a semantic indexing and fusion of
medical media. This fusion operates before the query processing (retrieval) and
works at an UMLS-compliant conceptual indexing level. Our purpose is to study
various techniques related to semantic data alignment, preprocessing, fusion,
clustering and retrieval, by evaluating the various techniques and highlighting
future research directions. The alignment and the preprocessing are based on
partial text/image retrieval feedback and on the data structure. We analyze
various probabilistic, fuzzy and evidence-based approaches for the fusion
process and different similarity functions for the retrieval process. All the
proposed methods are evaluated on the Cross Language Evaluation Forum's (CLEF)
medical image retrieval benchmark, by focusing also on a more homogeneous
component medical image database: the Pathology Education Instructional
Resource (PEIR).


title:
On the Fourier Spectra of the Infinite Families of Quadratic APN
  Functions

abstract:
  It is well known that a quadratic function defined on a finite field of odd
degree is almost bent (AB) if and only if it is almost perfect nonlinear (APN).
For the even degree case there is no apparent relationship between the values
in the Fourier spectrum of a function and the APN property. In this article we
compute the Fourier spectrum of the new quadranomial family of APN functions.
With this result, all known infinite families of APN functions now have their
Fourier spectra and hence their nonlinearities computed.


title: Work distributions in the T=0 Random Field Ising Model

abstract:
  We perform a numerical study of the three-dimensional Random Field
  Ising Model at T=0. We compare work distributions along metastable
trajectories obtained with the single-spin flip dynamics with the distribution
of the internal energy change along equilibrium trajectories. The goal is to
investigate the possibility of extending the Crooks fluctuation theorem to zero
temperature when, instead of the standard ensemble statistics, one considers
the ensemble generated by the quenched disorder. We show that a simple
extension of Crooks fails close to the disordered induced equilibrium phase
transition due to the fact that work and internal energy distributions are very
asymmetric.


title: Automated Induction for Complex Data Structures

abstract:
  We propose a procedure for automated implicit inductive theorem proving for
equational specifications made of rewrite rules with conditions and
constraints. The constraints are interpreted over constructor terms
(representing data values), and may express syntactic equality, disequality,
ordering and also membership in a fixed tree language. Constrained equational
axioms between constructor terms are supported and can be used in order to
specify complex data structures like sets, sorted lists, trees, powerlists...
  Our procedure is based on tree grammars with constraints, a formalism which
can describe exactly the initial model of the given specification (when it is
sufficiently complete and terminating). They are used in the inductive proofs
first as an induction scheme for the generation of subgoals at induction steps,
second for checking validity and redundancy criteria by reduction to an
emptiness problem, and third for defining and solving membership constraints.
  We show that the procedure is sound and refutationally complete. It
generalizes former test set induction techniques and yields natural proofs for
several non-trivial examples presented in the paper, these examples are
difficult to specify and carry on automatically with related induction
procedures.


title: The time evolution of marginally trapped surfaces

abstract:
  In previous work we have shown the existence of a dynamical horizon or
marginally trapped tube (MOTT) containing a given strictly stable marginally
outer trapped surface (MOTS). In this paper we show some results on the global
behavior of MOTTs assuming the null energy condition. In particular we show
that MOTSs persist in the sense that every Cauchy surface in the future of a
given Cauchy surface containing a MOTS also must contain a MOTS. We describe a
situation where the evolving outermost MOTS must jump during the coalescence of
two seperate MOTSs. We furthermore characterize the behavior of MOTSs in the
case that the principal eigenvalue vanishes under a genericity assumption. This
leads to a regularity result for the tube of outermost MOTSs under the
genericity assumption. This tube is then smooth up to finitely many jump times.
Finally we discuss the relation of MOTSs to singularities of a space-time.


title:
Low energy high angular resolution neutral atom detection by means of
  micro-shuttering techniques: the BepiColombo SERENA/ELENA sensor

abstract:
  The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA
cornerstone BepiColombo mission to Mercury (in the SERENA instrument package)
is a new kind of low energetic neutral atoms instrument, mostly devoted to
sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV,
within 1-D (2x76 deg). ELENA is a Time-of-Flight (TOF) system, based on
oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical
gratings: the incoming neutral particles directly impinge upon the entrance
with a definite timing (START) and arrive to a STOP detector after a flight
path. After a brief dissertation on the achievable scientific objectives, this
paper describes the instrument, with the new design techniques approached for
the neutral particles identification and the nano-techniques used for designing
and manufacturing the nano-structure shuttering core of the ELENA sensor. The
expected count-rates, based on the Hermean environment features, are shortly
presented and discussed. Such design technologies could be fruitfully exported
to different applications for planetary exploration.


title:
Tunable dynamical channel blockade in double-dot Aharonov-Bohm
  interferometers

abstract:
  We study electronic transport through an Aharonov-Bohm interferometer with
single-level quantum dots embedded in the two arms. The full counting
statistics in the shot-noise regime is calculated to first order in the
tunnel-coupling strength. The interplay of interference and charging energy in
the dots leads to a dynamical channel blockade that is tunable by the magnetic
flux penetrating the Aharonov-Bohm ring. We find super-Poissonian behavior with
diverging second and higher cumulants when the Aharonov-Bohm flux approaches an
integer multiple of the flux quantum.


title: Generalized power method for sparse principal component analysis

abstract:
  In this paper we develop a new approach to sparse principal component
analysis (sparse PCA). We propose two single-unit and two block optimization
formulations of the sparse PCA problem, aimed at extracting a single sparse
dominant principal component of a data matrix, or more components at once,
respectively. While the initial formulations involve nonconvex functions, and
are therefore computationally intractable, we rewrite them into the form of an
optimization program involving maximization of a convex function on a compact
set. The dimension of the search space is decreased enormously if the data
matrix has many more columns (variables) than rows. We then propose and analyze
a simple gradient method suited for the task. It appears that our algorithm has
best convergence properties in the case when either the objective function or
the feasible set are strongly convex, which is the case with our single-unit
formulations and can be enforced in the block case. Finally, we demonstrate
numerically on a set of random and gene expression test problems that our
approach outperforms existing algorithms both in quality of the obtained
solution and in computational speed.


title:
On the deformation theory of structure constants for associative
  algebras

abstract:
  Algebraic scheme for constructing deformations of structure constants for
associative algebras generated by a deformation driving algebras (DDAs) is
discussed. An ideal of left divisors of zero plays a central role in this
construction. Deformations of associative three-dimensional algebras with the
DDA being a three-dimensional Lie algebra and their connection with integrable
systems are studied.


title: Counting decomposable multivariate polynomials

abstract:
  A polynomial f (multivariate over a field) is decomposable if f = g(h) with g
univariate of degree at least 2. We determine the dimension (over an
algebraically closed field) of the set of decomposables, and an approximation
to their number over a finite field. The relative error in our approximations
is exponentially decaying in the input size.


title:
Space Weathering on Near-Earth Objects investigated by neutral-particle
  detection

abstract:
  The ion-sputtering (IS) process is active in many planetary environments in
the Solar System where plasma precipitates directly on the surface (for
instance, Mercury, Moon, Europa). In particular, solar-wind sputtering is one
of the most important agents for the surface erosion of a Near-Earth Object
(NEO), acting together with other surface release processes, such as Photon
Stimulated Desorption (PSD), Thermal Desorption (TD) and Micrometeoroid Impact
Vaporization (MIV). The energy distribution of the IS-released neutrals peaks
at a few eVs and extends up to hundreds of eVs. Since all other release
processes produce particles of lower energies, the presence of neutral atoms in
the energy range above 10 eV and below a few keVs (Sputtered High-Energy Atoms
- SHEA) identifies the IS process. SHEA easily escape from the NEO, due to
NEO's extremely weak gravity. Detection and analysis of SHEA will give
important information on surface-loss processes as well as on surface elemental
composition. The investigation of the active release processes, as a function
of the external conditions and the NEO surface properties, is crucial for
obtaining a clear view of the body's present loss rate as well as for getting
clues on its evolution, which depends significantly on space weather. In this
work, an attempt to analyze the processes that take place on the surface of
these small airless bodies, as a result of their exposure to the space
environment, has been realized. For this reason a new space weathering model
(Space Weathering on NEO - SPAWN), is presented. Moreover, an instrument
concept of a neutral-particle analyzer specifically designed for the
measurement of neutral density and the detection of SHEA from a NEO is proposed


title: A Note on Toric Varieties Associated to Moduli Spaces

abstract:
  In this note we give a brief review of the construction of a toric variety
$\mathcal{V}$ coming from a genus $g \geq 2$ Riemann surface $\Sigma^g$
equipped with a trinion, or pair of pants, decomposition. This was outlined by
J. Hurtubise and L. C. Jeffrey in \cite{JH1}. In \cite{T1} A. Tyurin used this
construction on a certain collection of trinion decomposed surfaces to produce
a variety $DM_g$ -- the so-called Delzant model of moduli space -- for each
genus $g.$ We conclude this note with some basic facts about the moment
polytopes of the varieties $\mathcal{V}.$ In particular, we show that the
varieties $DM_g$ constructed by Tyurin, and claimed to be smooth, are in fact
singular for $g \geq 3.$


title: Grain size dependence of barchan dune dynamics

abstract:
  The dependence of the barchan dune dynamics on the size of the grains
involved is investigated experimentally. Downsized barchan dune slices are
observed in a narrow water flow tube. The relaxation time from an initial
symmetric triangular heap towards an asymmetric shape attractor increases with
dune mass and decreases with grain size. The dune velocity increases with grain
size. In contrast, the velocity scaling and the shape of the barchan dune is
independent of the size of the grains.


title: Two-dimension plasma expansions with anisotropic pressure

abstract:
  A two-dimension self-similar solution is proposed for a plasma expansion with
anisotropic pressure. With the solution, it depends on the relationship between
the ratio of the longitudinal and the transverse temperature of the plasma,
$\kappa^2$ and the electron-ion mass ratio, $\mu$, that the plasma front is
composed by a part of hyperbolic (or a plane) and a small pointed projection at
the center or a part of an ellipse. Zhang and coworkers's experiments (PRL, 99,
167602 (2007))support our results for $\kappa^2\in(\tau,1]$. For
$\kappa^2\leq\tau$, there is an anomalous high-energy plasma emission at the
angle of near $90^{\text{o}}$ due to longitudinal Coulomb explosion.


title:
Coherence of single spins coupled to a nuclear spin bath of varying
  density

abstract:
  The dynamics of single electron and nuclear spins in a diamond lattice with
different 13C nuclear spin concentration is investigated. It is shown that
coherent control of up to three individual nuclei in a dense nuclear spin
cluster is feasible. The free induction decays of nuclear spin Bell states and
single nuclear coherences among 13C nuclear spins are compared and analyzed.
Reduction of a free induction decay time T2* and a coherence time T2 upon
increase of nuclear spin concentration has been found. For diamond material
with depleted concentration of nuclear spin, T2* as long as 30 microseconds and
T2 of up to 1.8 ms for the electron spin has been observed. The 13C
concentration dependence of T2* is explained by Fermi contact and dipolar
interactions with nuclei in the lattice. It has been found that T2 decreases
approximately as 1/n, where n is 13C concentration, as expected for an electron
spin interacting with a nuclear spin bath.


title:
Time-dependent energetic laser-ion acceleration by strong charge
  separation field

abstract:
  The laser-ion acceleration in the ultra-short and ultra-intense laser-matter
interactions attracts more and more interest nowadays. Since electrons gain
relativistic energy from laser pulse in a period of several femtoseconds and
driven away by the ponderomotive force of laser pulse, a huge charge-separation
field pulse is generated. In general cases, the ion acceleration is determined
by this charge-separation field. A novel general time-dependent solution for
laser-plasma isothermal expansions into a vacuum with different types of the
scale length of the density gradient which correspond to different charge
separation forms is obtained. The previous solutions are some special cases of
our general solution. A series of new solutions have been proposed and may be
used to predict new mechanisms of ion acceleration. However, many unaccounted
idiographic solutions that may be used to reveal new acceleration mode of ions
such as shock wave acceleration, may be deduced from our general solutions.


title:
Kinematic Analysis of a Serial - Parallel Machine Tool: the VERNE
  machine

abstract:
  The paper derives the inverse and the forward kinematic equations of a serial
- parallel 5-axis machine tool: the VERNE machine. This machine is composed of
a three-degree-of-freedom (DOF) parallel module and a two-DOF serial tilting
table. The parallel module consists of a moving platform that is connected to a
fixed base by three non-identical legs. These legs are connected in a way that
the combined effects of the three legs lead to an over-constrained mechanism
with complex motion. This motion is defined as a simultaneous combination of
rotation and translation. In this paper we propose symbolical methods that able
to calculate all kinematic solutions and identify the acceptable one by adding
analytical constraint on the disposition of legs of the parallel module.


title:
The Effect of Random Surface Inhomogeneities on Microresonator Spectral
  Properties: Theory and Modeling at Millimeter Wave Range

abstract:
  The influence of random surface inhomogeneities on spectral properties of
open microresonators is studied both theoretically and experimentally. To solve
the equations governing the dynamics of electromagnetic fields the method of
eigen-mode separation is applied previously developed with reference to
inhomogeneous systems subject to arbitrary external static potential. We prove
theoretically that it is the gradient mechanism of wave-surface scattering
which is the highly responsible for non-dissipative loss in the resonator. The
influence of side-boundary inhomogeneities on the resonator spectrum is shown
to be described in terms of effective renormalization of mode wave numbers
jointly with azimuth indices in the characteristic equation. To study
experimentally the effect of inhomogeneities on the resonator spectrum, the
method of modeling in the millimeter wave range is applied. As a model object
we use dielectric disc resonator (DDR) fitted with external inhomogeneities
randomly arranged at its side boundary. Experimental results show good
agreement with theoretical predictions as regards the predominance of the
gradient scattering mechanism. It is shown theoretically and confirmed in the
experiment that TM oscillations in the DDR are less affected by surface
inhomogeneities than TE oscillations with the same azimuth indices. The DDR
model chosen for our study as well as characteristic equations obtained
thereupon enable one to calculate both the eigen-frequencies and the Q-factors
of resonance spectral lines to fairly good accuracy. The results of
calculations agree well with obtained experimental data.


title:
Shubnikov-de Haas oscillations spectrum of the strongly correlated
  quasi-2D organic metal (ET)8[Hg4Cl12(C6H5Br)]2 under pressure

abstract:
  Pressure dependence of the Shubnikov-de Haas (SdH) oscillations spectra of
the quasi-two di- mensional organic metal (ET)8[Hg4Cl12(C6H5Br)]2 have been
studied up to 1.1 GPa in pulsed magnetic fields of up to 54 T. According to
band structure calculations, its Fermi surface can be regarded as a network of
compensated orbits. The SdH spectra exhibit many Fourier components typical of
such a network, most of them being forbidden in the framework of the
semiclassical model. Their amplitude remains large in all the pressure range
studied which likely rules out chemical potential oscillation as a dominant
contribution to their origin, in agreement with recent calculations relevant to
compensated Fermi liquids. In addition to a strong decrease of the magnetic
breakdown field and effective masses, the latter being likely due to a
reduction of the strength of electron correlations, a sizeable increase of the
scattering rate is observed as the applied pressure increases. This latter
point, which is at variance with data of most charge transfer salts is
discussed in connection with pressure-induced features of the temperature
dependence of the zero-field interlayer resistance


title: Detection of Vibrationally Excited CO in IRC+10216

abstract:
  Using the Submillimeter Array we have detected the J=3-2 and 2-1 rotational
transitions from within the first vibrationally excited state of CO toward the
extreme carbon star IRC+10216 (CW Leo). The emission remains spatially
unresolved with an angular resolution of ~2" and, given that the lines
originate from energy levels that are ~3100 K above the ground state, almost
certainly originates from a much smaller (~10^{14} cm) sized region close to
the stellar photosphere. Thermal excitation of the lines requires a gas density
of ~10^{9} cm^{-3}, about an order of magnitude higher than the expected gas
density based previous infrared observations and models of the inner dust shell
of IRC+10216.


title: The structure of maximal zero-sum free Sequences

abstract:
  Let n be an integer, and consider finite sequences of elements of the group
Z/nZ x Z/nZ. Such a sequence is called zero-sum free, if no subsequence has sum
zero. It is known that the maximal length of such a zero-sum free sequence is
2n-2, and Gao and Geroldinger conjectured that every zero-sum free sequence of
this length contains an element with multiplicity at least n-2. By recent
results of Gao, Geroldinger and Grynkiewicz, it essentially suffices to verify
the conjecture for n prime. Now fix a sequence (a_i) of length 2n-2 with
maximal multiplicity of elements at most n-3. There are different approeaches
to show that (a_i) contains a zero-sum; some work well when (a_i) does contain
elements with high multiplicity, others work well when all multiplicities are
small. The aim of this article is to initiate a systematic approach to property
B via the highest occurring multiplicities. Our main results are the following:
denote by m_1 >= m_2 the two maximal multiplicities of (a_i), and suppose that
n is sufficiently big and prime. Then (a_i) contains a zero-sum in any of the
following cases: when m_2 >= 2/3n, when m_1 > (1-c)n, and when m_2 < cn, for
some constant c > 0 not depending on anything.


title: Universal fluctuations in subdiffusive transport

abstract:
  Subdiffusive transport in tilted washboard potentials is studied within the
fractional Fokker-Planck equation approach, using the associated continuous
time random walk (CTRW) framework. The scaled subvelocity is shown to obey a
universal law, assuming the form of a stationary Levy-stable distribution. The
latter is defined by the index of subdiffusion alpha and the mean subvelocity
only, but interestingly depends neither on the bias strength nor on the
specific form of the potential. These scaled, universal subvelocity
fluctuations emerge due to the weak ergodicity breaking and are vanishing in
the limit of normal diffusion. The results of the analytical heuristic theory
are corroborated by Monte Carlo simulations of the underlying CTRW.


title: Twenty Digits of Some Integrals of the Prime Zeta Function

abstract:
  The double sum sum_(s >= 1) sum_p 1/(p^s log p^s) = 2.00666645... over the
inverse of the product of prime powers p^s and their logarithms, is computed to
24 decimal digits. The sum covers all primes p and all integer exponents s>=1.
The calculational strategy is adopted from Cohen's work which basically looks
at the fraction as the underivative of the Prime Zeta Function, and then
evaluates the integral by numerical methods.


title:
On the stability of the overconvergence under the direct image by a
  proper smooth morphism

abstract:
  Up to a translation in the language of arithmetic $\D$-modules, we prove a
conjecture of Berthelot on the preservation of the overconvergence under the
direct image by a smooth proper morphism of varieties over a perfect field of
characteristic $p>0$.


title: Skyrme-Random-Phase-Approximation description of E1 strength in 92-100Mo

abstract:
  The isovector dipole E1 strength in Mo isotopes with A=92,94,96,98,100 is
analyzed within the self-consistent separable random-phase approximation (SRPA)
model with Skyrme forces SkT6, SkM*, SLy6, and SkI3. The special attention is
paid to the low-energy region near the particle thresholds (4-12 MeV), which is
important for understanding of astrophysical processes. We show that, due to a
compensation effect, the influence of nuclear deformation on E1 strength below
10-12 MeV is quite modest. At the same time, in agreement with previous
predictions, the deformation increases the strength at higher energy. At 4-8
MeV the strength is mainly determined by the tail of E1 giant resonance. The
four Skyrme forces differ in description of the whole giant resonance but give
rather similar results below 12 MeV.


title: Coulomb corrections to superallowed beta decay in nuclei

abstract:
  Corrections to the superallowed beta decay matrix elements are evaluated in
perturbation theory using the notion of the isovector monopole resonance. The
calculation avoids the separation into different contributions and thus
presents a consistent, systematic and more transparent approach. Explicit
expressions for the Coulomb correction as a function of mass number A, are
given.


title: Generalized Berezin-Toeplitz quantization of Kaehler supermanifolds

abstract:
  We extend the construction of generalized Berezin and Berezin-Toeplitz
quantization to the case of compact Hodge supermanifolds. Our approach is based
on certain super-analogues of Rawnsley's coherent states. As applications, we
discuss the quantization of affine and projective superspaces. Furthermore, we
propose a definition of supersymmetric sigma-models on quantized Hodge
supermanifolds. The corresponding quantum field theories are finite and thus
yield supersymmetry-preserving regularizations for QFTs defined on flat
superspace.


title: Hybrid textures in minimal seesaw mass matrices

abstract:
  In the context of minimal seesaw framework, we study the implications of
Dirac and Majorana mass matrices in which two rigid properties coexist, namely,
equalities among mass matrix elements and texture zeros. In the first part of
the study, we discuss general possibilities of the Dirac and Majorana mass
matrices for neutrinos with such hybrid structures. We then classify the mass
matrices into realistic textures which are compatible with global neutrino
oscillation data and unrealistic ones which do not comply with the data. Among
the large number of general possibilities, we find that only 6 patterns are
consistent with the observations at the level of the most minimal number of
free parameters. These solutions have only 2 adjustable parameters, so that all
the mixing angles can be described in terms of the two mass differences or pure
numbers. We analyze these textures in detail and discuss their impacts for
future neutrino experiments and for leptogenesis.


title:
Theory of the field-induced BEC in the frustrated spin-1/2 dimer
  compound BaCuSi2O6

abstract:
  Building on recent neutron and NMR experiments, we investigate the
field-induced exotic criticality observed in the frustrated spin-1/2 dimer
compound BaCuSi2O6 using a frustrated model with two types of bilayers. A
semiclassical treatment of the effective hard-core boson model shows that
perfect inter-layer frustration leads to a 2D-like critical exponent phi=1
without logarithmic corrections and to a 3D low temperature phase with
different but non vanishing triplet populations in both types of bilayers.
These results further suggest a simple phenomenology in terms of a
field-dependent transverse coupling in the context of which we reproduce the
entire field-temperature phase diagram with Quantum Monte Carlo simulations.


title:
Photoactivation experiment on 197Au and its implications for the dipole
  strength in heavy nuclei

abstract:
  The 197Au(gamma,n) reaction is used as an activation standard for
photodisintegration studies on astrophysically relevant nuclei. At the
bremsstrahlung facility of the superconducting electron accelerator ELBE
(Electron Linear accelerator of high Brilliance and low Emittance) of
Forschungszentrum Dresden-Rossendorf, photoactivation measurements on 197Au
have been performed with bremsstrahlung endpoint energies from 8.0 to 15.5 MeV.
The measured activation yield is compared with previous experiments as well as
with calculations using Hauser-Feshbach statistical models. It is shown that
the experimental data are best described by a two-Lorentzian parametrization
with taking the axial deformation of 197Au into account. The experimental
197Au(gamma,n) reaction yield measured at ELBE via the photoactivation method
is found to be consistent with previous experimental data using photon
scattering or neutron detection methods.


title: High Energy Neutrino Astronomy: Status and Perspectives

abstract:
  The year 2008 has witnessed remarkable steps in developing high energy
neutrino telescopes. IceCube at the South Pole has been deployed with 40 of its
planned 80 strings and reached half a cubic kilometer instrumented volume, in
the Mediterranean Sea the "first-stage" neutrino telescope ANTARES has been
completed and takes data with 12 strings. The next years will be key years for
opening the neutrino window to the high energy universe. IceCube is presently
entering a region with realistic discovery potential. Early discoveries (or
non-discoveries) with IceCube will strongly influence the design and the
estimated discovery chances of the Northern equivalent KM3NeT. Following
theoretical estimates, cubic kilometer telescopes may just scratch the regions
of discovery. Therefore detectors presently planned should reach sensitivities
substantially beyond those of IceCube.


title: Gemini/GMOS search of massive binaries in the ionizing cluster of 30 Dor

abstract:
  If binaries are common among massive stars, it will have important
consequences for the derivation of fundamental properties like the cluster age,
IMF and dynamical mass. Making use of the multiplexing facilities of Gemini
Multi Object Spectrograph (GMOS) we were able to investigate the presence of
binary stars within the ionising cluster of 30 Doradus. From a seven epochs
observing campaign at Gemini South we detect a binary candidate rate of about
50%, which is consistent with an intrinsic 100% binary rate among massive
stars. We find that single epoch determinations of the velocity dispersion give
values around 30 km/s . After correcting the global velocity dispersion for the
binary orbital motions, the true cluster velocity dispersion is 8.3 km/s. This
value implies a virial mass of about 4.5E5 Msun or 8 percent of the mass
calculated using the single epoch value. The binary corrected virial mass
estimate is consistent with photometric mass determinations thus suggesting
that NGC 2070 is a firm candidate for a future globular cluster.


title:
Extremum complexity in the monodimensional ideal gas: the piecewise
  uniform density distribution approximation

abstract:
  In this work, it is suggested that the extremum complexity distribution of a
high dimensional dynamical system can be interpreted as a piecewise uniform
distribution in the phase space of its accessible states. When these
distributions are expressed as one--particle distribution functions, this leads
to piecewise exponential functions. It seems plausible to use these
distributions in some systems out of equilibrium, thus greatly simplifying
their description. In particular, here we study an isolated ideal
monodimensional gas far from equilibrium that presents an energy distribution
formed by two non--overlapping Gaussian distribution functions. This is
demonstrated by numerical simulations. Also, some previous laboratory
experiments with granular systems seem to display this kind of distributions.


title:
Is J 133658.3-295105 a Radio Source at z >= 1.0 or at the Distance of M
  83?

abstract:
  We present Gemini optical imaging and spectroscopy of the radio source J
133658.3-295105. This source has been suggested to be the core of an FR II
radio source with two detected lobes. J 133658.3-295105 and its lobes are
aligned with the optical nucleus of M 83 and with three other radio sources at
the M 83 bulge outer region. These radio sources are neither supernova remnants
nor H II regions. This curious configuration prompted us to try to determine
the distance to J 133658.3-295105. We detected H_alpha emission redshifted by ~
130 km s^-1 with respect to an M 83 H II region 2.5" east-southeast of the
radio source. We do not detect other redshifted emission lines of an optical
counterpart down to m_i = 22.2 +/- 0.8. Two different scenarios are proposed:
the radio source is at z >= 2.5, a much larger distance than the previously
proposed lower limit z >= 1.0, or the object was ejected by a gravitational
recoil event from the M 83 nucleus. This nucleus is undergoing a strong
dynamical evolution, judging from previous three-dimensional spectroscopy.


title: The Upper Atmosphere of HD17156b

abstract:
  HD17156b is a newly-found transiting extrasolar giant planet (EGP) that
orbits its G-type host star in a highly eccentric orbit (e~0.67) with an
orbital semi-major axis of 0.16 AU. Its period, 21.2 Earth days, is the longest
among the known transiting planets. The atmosphere of the planet undergoes a
27-fold variation in stellar irradiation during each orbit, making it an
interesting subject for atmospheric modelling. We have used a three-dimensional
model of the upper atmosphere and ionosphere for extrasolar gas giants in order
to simulate the progress of HD17156b along its eccentric orbit. Here we present
the results of these simulations and discuss the stability, circulation, and
composition in its upper atmosphere. Contrary to the well-known transiting
planet HD209458b, we find that the atmosphere of HD17156b is unlikely to escape
hydrodynamically at any point along the orbit, even if the upper atmosphere is
almost entirely composed of atomic hydrogen and H+, and infrared cooling by H3+
ions is negligible. The nature of the upper atmosphere is sensitive to to the
composition of the thermosphere, and in particular to the mixing ratio of H2,
as the availability of H2 regulates radiative cooling. In light of different
simulations we make specific predictions about the thermosphere-ionosphere
system of HD17156b that can potentially be verified by observations.


title:
Interferometry signatures for QCD first-order phase transition in heavy
  ion collisions at GSI-FAIR energies

abstract:
  Using the technique of quantum transport of the interfering pair we examine
the Hanbury-Brown-Twiss (HBT) interferometry signatures for the
particle-emitting sources of pions and kaons produced in the heavy ion
collisions at GSI-FAIR energies. The evolution of the sources is described by
relativistic hydrodynamics with the system equation of state of the first-order
phase transition from quark-gluon plasma (QGP) to hadronic matter. We use
quantum probability amplitudes in a path-integral formalism to calculate the
two-particle correlation functions, where the effects of particle decay and
multiple scattering are taken into consideration. We find that the HBT radii of
kaons are smaller than those of pions for the same initial conditions. Both the
HBT radii of pions and kaons increase with the system initial energy density.
The HBT lifetimes of the pion and kaon sources are sensitive to the initial
energy density. They are significantly prolonged when the initial energy
density is tuned to the phase boundary between the QGP and mixed phase. This
prolongations of the HBT lifetimes of pions and kaons may likely be observed in
the heavy ion collisions with an incident energy in the GSI-FAIR energy range.


title:
2D non-LTE radiative modelling of He I spectral lines formed in solar
  prominences

abstract:
  The diagnosis of new high-resolution spectropolarimetric observations of
solar prominences made in the visible and near-infrared mainly, requires a
radiative modelling taking into account for both multi-dimensional geometry and
complex atomic models. Hereafter we contribute to the improvement of the
diagnosis based on the observation of He I multiplets, by considering 2D
non-LTE unpolarized radiation transfer, and taking also into account the atomic
fine structure of helium. It is an improvement and a direct application of the
multi-grid Gauss-Seidel/SOR iterative scheme in 2D cartesian geometry developed
by us. It allows us to compute realistic emergent intensity profiles for the He
I 10830 A and D3 multiplets, which can be directly compared to the simultaneous
and high-resolution observations made at THeMIS. A preliminary 2D multi-thread
modelling is also discussed.


title:
The falling appart of the tagged fragment and the asymptotic
  disintegration of the Brownian height fragmentation

abstract:
  We present a further analysis of the fragmentation at heights of the
normalized Brownian excursion. Specifically we study a representation for the
mass of a tagged fragment in terms of a Doob transformation of the 1/2-stable
subordinator and use it to study its jumps; this accounts for a description of
how a typical fragment falls apart. These results carry over to the height
fragmentation of the stable tree. Additionally, the sizes of the fragments in
the Brownian fragmentation when it is about to reduce to dust are described in
a limit theorem.


title: Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2

abstract:
  Inelastic neutron scattering measurements on single crystals of
superconducting BaFe1.84Co0.16As2 reveal a magnetic excitation located at
wavevectors (1/2 1/2 L) in tetragonal notation. On cooling below TC, a clear
resonance peak is observed at this wavevector with an energy of 8.6(0.5) meV,
corresponding to 4.5(0.3) kBTC. This is in good agreement with the canonical
value of 5 kBTC observed in the cuprates. The spectrum shows strong dispersion
in the tetragonal plane but very weak dispersion along the c-axis, indicating
that the magnetic fluctuations are two-dimensional in nature. This is in sharp
contrast to the anisotropic three dimensional spin excitations seen in the
undoped parent compounds.


title:
Feasibility of free space quantum key distribution with coherent
  polarization states

abstract:
  We demonstrate for the first time the feasibility of free space quantum key
distribution with continuous variables under real atmospheric conditions. More
specifically, we transmit coherent polarization states over a 100m free space
channel on the roof of our institute's building. In our scheme, signal and
local oscillator are combined in a single spatial mode which auto-compensates
atmospheric fluctuations and results in an excellent interference. Furthermore,
the local oscillator acts as spatial and spectral filter thus allowing
unrestrained daylight operation.


title: Higher order corrections to H+- production

abstract:
  I discuss recent calculations of higher-order corrections to charged Higgs
production through various partonic subprocesses. Particular attention is paid
to H- production in association with a top quark at the LHC.


title:
One-loop Electro-Weak Corrections to Three-jet Observables of b-quarks
  in e+e- Annihilations

abstract:
  We compute the full one-loop EW contributions of O(\alpha_S alpha_EM^3)
entering the electron-positron into two b-quarks and one gluon cross section at
the Z peak and LC energies. We include both factorisable and non-factorisable
virtual corrections, photon bremsstrahlung but not the real emission of W^\pm
and Z bosons. Their importance for the measurement of alpha_S from jet rates
and shape variables is explained qualitatively and illustrated quantitatively.
Their impact on the forward-backward asymmetry is also analysed.


title: LCFI Vertex Package

abstract:
  The LCFIVertex software, developed by the Linear Collider Flavour
Identification (LCFI) collaboration and providing tools for vertexing, flavour
tagging and quark charge determination for low-mass vertex detectors of high
point resolution is presented. Particular emphasis is given to code extensions
since the first release in April 2007. A recently developed new vertex finder,
ZVMST, and its performance at sqrt(s) = 91.2 GeV are described in more detail.


title:
From global symmetries to local currents: the free (scalar) case in 4
  dimensions

abstract:
  Within the framework of algebraic quantum field theory, we propose a new
method of constructing local generators of (global) gauge symmetries in field
theoretic models, starting from the existence of unitary operators implementing
locally the flip automorphism on the doubled theory. We show, in the simple
example of the internal symmetries of a multiplet of free scalar fields, that
through the pointlike limit of such local generators the conserved Wightman
currents associated with the symmetries are recovered.


title:
Maximal order of growth for the resonance counting functions for generic
  potentials in even dimensions

abstract:
  We prove that the resonance counting functions for Schr\"odinger operators
$H_V = - \Delta + V$ on $L^2 (\R^d)$, for $d \geq 2$ {\it even}, with generic,
compactly-supported, real- or complex-valued potentials $V$, have the maximal
order of growth $d$ on each sheet $\Lambda_m$, $m \in \Z \backslash \{0 \}$, of
the logarithmic Riemann surface. We obtain this result by constructing, for
each $m \in \Z \backslash \{0 \}$, a plurisubharmonic function from a
scattering determinant whose zeros on the physical sheet $\Lambda_0$ determine
the poles on $\Lambda_m$. We prove that the order of growth of the counting
function is related to a suitable estimate on this function that we establish
for generic potentials. We also show that for a potential that is the
characteristic function of a ball, the resonance counting function is bounded
below by $C_m r^d$ on each sheet $\Lambda_m$, $m \in \Z \backslash \{0\}$.


title: The Depth of a Hypersubstitution

abstract:
  For given depth of a we derive a formula for the depth of the image of that
term under a given hypersubstitution.


title: Crystalline multilayers of the confined Yukawa system

abstract:
  The phase diagram of Yukawa particles confined between two parallel hard
walls is calculated at zero-temperature beyond the bilayer regime by
lattice-sum-minimization. Tuning the screening, a rich phase behavior is found
in the regime bounded by stable two-triangular layers and 3-square layers. In
this regime, alternating prism phases with square and triangular basis,
structures derived from a hcp bulk lattice, and a structure with two outer
layers and two inner staggered rectangular layers, reminiscent of a Belgian
waffle iron, are stable. These structures are verifiable in experiments on
charged colloidal suspensions and dusty plasma sheets.


title: Multi-Hypersubstitutions and Colored Solid Varieties

abstract:
  Hypersubstitutions are mappings which map operation symbols to terms. Terms
can be visualized by trees. Hypersubstitutions can be extended to mappings
defined on sets of trees. The nodes of the trees, describing terms, are
labelled by operation symbols and by colors, i.e. certain positive integers. We
are interested in mappings which map differently colored operation symbols to
different terms. In this paper we extend the theory of hypersubstitutions and
solid varieties to multi-hypersubstitutions and colored solid varieties. We
develop the interconnections between such colored terms and
multi-hypersubstitutions and the equational theory of Universal Algebra. The
collection of all varieties of a given type forms a complete lattice which is
very complex and difficult to study; multi-hypersubstitutions and colored solid
varieties offer a new method to study complete sublattices of this lattice.


title: On some cohomological properties of almost complex manifolds

abstract:
  We study a special type of almost complex structures, called pure and full
and introduced by T.J. Li and W. Zhang, in relation to symplectic structures
and Hard Lefschetz condition. We provide sufficient conditions to the existence
of the above type of almost complex structures on compact quotients of Lie
groups by discrete subgroups. We obtain families of pure and full almost
complex structures on compact nilmanifolds and solvmanifolds. Some of these
families are parametrized by real 2-forms which are anti-invariant with respect
to the almost complex structures.


title: Tri-bimaximal lepton mixing from symmetry only

abstract:
  We construct a model for tri-bimaximal lepton mixing which employs only
family symmetries and their soft breaking; neither vacuum alignment nor
supersymmetry, extra dimensions, or non-renormalizable terms are used in our
model. It is an extension of the Standard Model making use of the seesaw
mechanism with five right-handed neutrino singlets. The scalar sector comprises
four Higgs doublets and one complex gauge singlet. The horizontal symmetry of
our model is based on the permutation group S_3 of the lepton families together
with the three family lepton numbers--united this constitutes a symmetry group
Delta(6\infty^2). The model makes no predictions for the neutrino masses.


title: Twist operator correlation functions in O(n) loop models

abstract:
  Using conformal field theoretic methods we calculate correlation functions of
geometric observables in the loop representation of the O(n) model at the
critical point. We focus on correlation functions containing twist operators,
combining these with anchored loops, boundaries with SLE processes and with
double SLE processes.
  We focus further upon n=0, representing self-avoiding loops, which
corresponds to a logarithmic conformal field theory (LCFT) with c=0. In this
limit the twist operator plays the role of a zero weight indicator operator,
which we verify by comparison with known examples. Using the additional
conditions imposed by the twist operator null-states, we derive a new explicit
result for the probabilities that an SLE_{8/3} wind in various ways about two
points in the upper half plane, e.g. that the SLE passes to the left of both
points.
  The collection of c=0 logarithmic CFT operators that we use deriving the
winding probabilities is novel, highlighting a potential incompatibility caused
by the presence of two distinct logarithmic partners to the stress tensor
within the theory. We provide evidence that both partners do appear in the
theory, one in the bulk and one on the boundary and that the incompatibility is
resolved by restrictive bulk-boundary fusion rules.