title:
Modules on involutive quantales: canonical Hilbert structure,
  applications to sheaf theory

abstract:
  We explain the precise relationship between two module-theoretic descriptions
of sheaves on an involutive quantale, namely the description via so-called
Hilbert structures on modules and that via so-called principally generated
modules. For a principally generated module satisfying a suitable symmetry
condition we observe the existence of a canonical Hilbert structure. We prove
that, when working over a modular quantal frame, a module bears a Hilbert
structure if and only if it is principally generated and symmetric, in which
case its Hilbert structure is necessarily the canonical one. We indicate
applications to sheaves on locales, on quantal frames and even on sites.


title: Symmetric ladders and G-biliaison

abstract:
  We study the family of ideals generated by minors of mixed size contained in
a ladder of a symmetric matrix from the point of view of liaison theory. We
prove that they can be obtained from ideals of linear forms by ascending
G-biliaison. In particular, they are glicci.


title: Near-Infrared Studies of V1280 Sco (Nova Scorpii 2007)

abstract:
  We present spectroscopic and photometric results of Nova V1280 Sco which was
discovered in outburst in early 2007 February. The large number of spectra
obtained of the object leads to one of the most extensive, near-infrared
spectral studies of a classical nova. The spectra evolve from a P-Cygni phase
to an emission-line phase and at a later stage is dominated by emission from
the dust that formed in this nova. A detailed model is computed to identify and
study characteristics of the spectral lines. Inferences from the model address
the vexing question of which novae have the ability to form dust. It is
demonstrated, and strikingly corroborated with observations, that the presence
of lines in the early spectra of low-ionization species like Na and Mg -
indicative of low temperature conditions - appear to be reliable indicators
that dust will form in the ejecta. It is theoretically expected that mass loss
during a nova outburst is a sustained process. Spectroscopic evidence for such
a sustained mass loss, obtained by tracing the evolution of a P-Cygni feature
in the Brackett gamma line, is presented here allowing a lower limit of 25-27
days to be set for the mass-loss duration. Photometric data recording the
nova's extended 12 day climb to peak brightness after discovery is used to
establish an early fireball expansion and also show that the ejection began
well before maximum brightness. The JHK light curves indicate the nova had a
fairly strong second outburst around 100 days after the first.


title:
An exact relation between Eulerian and Lagrangian velocity increment
  statistics

abstract:
  We present a formal connection between Lagrangian and Eulerian velocity
increment distributions which is applicable to a wide range of turbulent
systems ranging from turbulence in incompressible fluids to magnetohydrodynamic
turbulence. For the case of the inverse cascade regime of two-dimensional
turbulence we numerically estimate the transition probabilities involved in
this connection. In this context we are able to directly identify the processes
leading to strongly non-Gaussian statistics for the Lagrangian velocity
increments.


title:
Iterating the hessian: a dynamical system on the moduli space of
  elliptic curves and dessins d'enfants

abstract:
  Each elliptic curve can be embedded uniquely in the projective plane, up to
projective equivalence. The hessian curve of the embedding is generically a new
elliptic curve, whose isomorphism type depends only on that of the initial
elliptic curve. One gets like this a rational map from the moduli space of
elliptic curves to itself. We call it the hessian dynamical system. We compute
it in terms of the $j$-invariant of elliptic curves. We deduce that, seen as a
map from a projective line to itself, it has 3 critical values, which
correspond to the point at infinity of the moduli space and to the two elliptic
curves with special symmetries. Moreover, it sends the set of critical values
into itself, which shows that all its iterates have the same set of critical
values. One gets like this a sequence of dessins d'enfants. We describe an
algorithm allowing to construct this sequence.


title: Coherent operation of superconducting flux qubits

abstract:
  We study the quantum operation of coupled superconducting flux qubits under a
microwave irradiation. The flux qubits can be described as magnetic dipole
moments in the limit of weak microwave field amplitude consistent with usual
experimental situations. With the Hamiltonian for coupled qubits under a
microwave field, we show that a strong coupling enables to realize the high
performance controlled-NOT gate operation. For practical quantum computing we
analyze the effect of microwave on switching function of phase-coupled qubits.


title: Towards a More Accurate Carrier Sensing Model for CSMA Wireless Networks

abstract:
  This work calls into question a substantial body of past work on CSMA
wireless networks. In the majority of studies on CSMA wireless networks, a
contention graph is used to model the carrier sensing relationships (CS) among
links. This is a 0-1 model in which two links can either sense each other
completely or not. In real experiments, we observed that this is generally not
the case: the CS relationship between the links are often probabilistic and can
vary dynamically over time. This is the case even if the distance between the
links is fixed and there is no drastic change in the environment. Furthermore,
this partial carrier sensing relationship is prevalent and occurs over a wide
range of distances between the links. This observation is not consistent with
the 0-1 contention graph and implies that many results and conclusions drawn
from previous theoretical studies need to be re-examined. This paper
establishes a more accurate CS model with the objective of laying down a
foundation for future theoretical studies that reflect reality. Towards that
end, we set up detailed experiments to investigate the partial carrier sensing
phenomenon. We discuss the implications and the use of our partial carrier
sensing model in network analysis.


title: Q-modules are Q-suplattices

abstract:
  It is well known that the internal suplattices in the topos of sheaves on a
locale are precisely the modules on that locale. Using enriched category theory
and a lemma on KZ doctrines we prove (the generalization of) this fact in the
case of ordered sheaves on a small quantaloid. Comparing module-equivalence
with sheaf-equivalence for quantaloids and using the notion of centre of a
quantaloid, we refine a result of F. Borceux and E. Vitale.


title: High-speed Jet Formation after Solid Object Impact

abstract:
  A circular disc impacting on a water surface creates a remarkably vigorous
jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in
a single point halfway down the cavity. Immediately after closure two fast
sharp-pointed jets are observed shooting up- and downwards from the closure
location, which by then has turned into a stagnation point surrounded by a
locally hyperbolic flow pattern. This flow, however, is {\it not} the mechanism
feeding the two jets. Using high-speed imaging and numerical simulations we
show that jetting is fed by the local flow around the base of the jet, which is
forced by the colliding cavity walls. Based on this insight, we then show how
the analytical description of a collapsing void (using a line of sinks along
the axis of symmetry) can be continued beyond the time of pinch-off to obtain a
quantitative model for jet formation which is in good agreement with the
numerical and experimental data.


title:
MAPLE subroutines for computing Milnor and Tyurina numbers of
  hypersurface singularities with application to Arnol'd adjacencies

abstract:
  In the present paper MAPLE subroutines computing Milnor and Tyurina numbers
of an isolated algebraic hypersurface singularity are presented and described
in detail. They represents examples, and perhaps the first ones, of a MAPLE
implementation of local monomial ordering.
  As an application, the last section is devoted to writing down equations of
algebraic stratifications of Kuranishi spaces of simple Arnol'd singularities:
they geometrically represents, by means of inclusions of algebraic subsets, the
partial ordering on classes of simple singularities induced by the adjacency
relation.


title: The boiling suppression of liquid nitrogen

abstract:
  When He gas is injected from room temperature into boiling liquid N$_{2}$,
boiling is suppressed, leaving liquid surface flat like a mirror. Although the
qualitative explanation for this phenomenon is known [Minkoff G J \textit{et
al}. Nature 1957;180(4599):1413-4.], it has not been studied quantitatively and
comprehensively yet. In this report, we made careful simultaneous measurements
of temperature and weight variation of the liquid. The results clearly indicate
that the boiling suppression is caused by cooling of the liquid with "internal
evaporation" of N$_{2}$ into the He bubbles.


title: Imaging with parallel ray-rotation sheets

abstract:
  A ray-rotation sheet consists of miniaturized optical components that
function - ray optically - as a homogeneous medium that rotates the local
direction of transmitted light rays around the sheet normal by an arbitrary
angle [A. C. Hamilton et al., arXiv:0809.2646 (2008)]. Here we show that two or
more parallel ray-rotation sheets perform imaging between two planes. The image
is unscaled and un-rotated. No other planes are imaged. When seen through
parallel ray-rotation sheets, planes that are not imaged appear rotated,
whereby the rotation angle changes with the ratio between the observer's and
the object plane's distance from the sheets.


title:
On isometric dilations of product systems of C*-correspondences and
  applications to families of contractions associated to higher-rank graphs

abstract:
  Let E be a product system of C*-correspondences over N^r. Some sufficient
conditions for the existence of a not necessarily regular isometric dilation of
a completely contractive representation of E are established and difference
between regular and *-regular dilations discussed. It is in particular shown
that a minimal isometric dilation is *-regular if and only if it is doubly
commuting. The case of product systems associated with higher-rank graphs is
analysed in detail.


title:
Convergence to stable laws for a class of multidimensional stochastic
  recursions

abstract:
  We consider a Markov chain $\{X_n\}_{n=0}^\8$ on $\R^d$ defined by the
stochastic recursion $X_{n}=M_n X_{n-1}+Q_n$, where $(Q_n,M_n)$ are i.i.d.
random variables taking values in the affine group $H=\R^d\rtimes {\rm
GL}(\R^d)$. Assume that $M_n$ takes values in the similarity group of $\R^d$,
and the Markov chain has a unique stationary measure $\nu$, which has unbounded
support. We denote by $|M_n|$ the expansion coefficient of $M_n$ and we assume
$\E |M|^\a=1$ for some positive $\a$. We show that the partial sums
$S_n=\sum_{k=0}^n X_k$, properly normalized, converge to a normal law ($\a\ge
2$) or to an infinitely divisible law, which is stable in a natural sense
($\a<2$). These laws are fully nondegenerate, if $\nu$ is not supported on an
affine hyperplane. Under a natural hypothesis, we prove also a local limit
theorem for the sums $S_n$. If $\a\le 2$, proofs are based on the homogeneity
at infinity of $\nu$ and on a detailed spectral analysis of a family of Fourier
operators $P_v$ considered as perturbations of the transition operator $P$ of
the chain $\{X_n \}$. The characteristic function of the limit law has a simple
expression in terms of moments of $\nu$ ($\a > 2$) or of the tails of $\nu$ and
of stationary measure for an associated Markov operator ($\a\le 2$). We extend
the results to the situation where $M_n$ is a random generalized similarity.


title:
Fermat's principle with complex refractive indices and local light-ray
  rotation

abstract:
  We describe local light-ray rotation in terms of complex refractive indices.
We show that Fermat's principle holds, and we derive an extended Snell's law.
The change in the angle of a light ray with respect to the normal to a
refractive-index interface is described by the modulus of the refractive-index
ratio, the rotation around the interface normal is described by the argument of
the refractive-index ratio.


title: Artin t-Motifs

abstract:
  We show that analytically trivial t-motifs satisfy a Tannakian duality,
without restrictions on the base field, save for that it be of generic
characteristic. We show that the group of components of the t-motivic Galois
group coincides with the absolute Galois group of the base field.


title: Gravitational radiation from pulsar glitches

abstract:
  The nonaxisymmetric Ekman flow excited inside a neutron star following a
rotational glitch is calculated analytically including stratification and
compressibility. For the largest glitches, the gravitational wave strain
produced by the hydrodynamic mass quadrupole moment approaches the sensitivity
range of advanced long-baseline interferometers. It is shown that the
viscosity, compressibility, and orientation of the star can be inferred in
principle from the width and amplitude ratios of the Fourier peaks (at the spin
frequency and its first harmonic) observed in the gravitational wave spectrum
in the plus and cross polarizations. These transport coefficients constrain the
equation of state of bulk nuclear matter, because they depend sensitively on
the degree of superfluidity.


title:
Thermoballistic spin-polarized electron transport in paramagnetic
  semiconductors

abstract:
  Spin-polarized electron transport in diluted magnetic semiconductors (DMS) in
the paramagnetic phase is described within the thermoballistic transport model.
In this (semiclassical) model, the ballistic and diffusive transport mechanisms
are unified in terms of a thermoballistic current in which electrons move
ballistically across intervals enclosed between arbitrarily distributed points
of local thermal equilibrium. The contribution of each interval to the current
is governed by the momentum relaxation length. Spin relaxation is assumed to
take place during the ballistic electron motion. In paramagnetic DMS exposed to
an external magnetic field, the conduction band is spin-split due to the giant
Zeeman effect. In order to deal with this situation, we extend our previous
formulation of thermoballistic spin-polarized transport so as to take into
account an arbitrary (position-dependent) spin splitting of the conduction
band. The current and density spin polarizations as well as the
magnetoresistance are each obtained as the sum of an equilibrium term
determined by the spin-relaxed chemical potential, and an off-equilibrium
contribution expressed in terms of a spin transport function that is related to
the splitting of the spin-resolved chemical potentials. The procedures for the
calculation of the spin-relaxed chemical potential and of the spin transport
function are outlined. As an illustrative example, we apply the thermoballistic
description to spin-polarized transport in DMS/NMS/DMS heterostructures formed
of a nonmagnetic semiconducting sample (NMS) sandwiched between two DMS layers.
We evaluate the current spin polarization and the magnetoresistance for this
case and, in the limit of small momentum relaxation length, find our results to
agree with those of the standard drift-diffusion approch to electron transport.


title: New physics search in the LHCb era

abstract:
  We present theoretical and experimental preparations for an indirect search
for new physics using the rare decay $\bar B_d \to \bar K^* l^+ l^-$. We design
new observables with very small theoretical uncertainties and good experimental
resolution.


title:
Avoiding the blue spectrum and the fine-tuning of initial conditions in
  hybrid inflation

abstract:
  Hybrid inflation faces two well-known problems: the blue spectrum of the
non-supersymmetric version of the model and the fine-tuning of the initial
conditions of the fields leading to sufficient inflation to account for the
standard cosmological problems. They are investigated by studying the exact
two-fields dynamics instead of assuming slow-roll. When the field values are
restricted to be less than the reduced Planck mass, a non-negligible part of
the initial condition space (around 15% depending on potential parameters)
leads to successful inflation. Most of it is located outside the usual
inflationary valley and organized in continuous patterns instead of being
isolated as previously found. Their existence is explained and their properties
are studied. This shows that no excessive fine-tuning is required for
successful hybrid inflation. Moreover, by extending the initial condition space
to planckian-like or super-planckian values, inflation becomes generically
sufficiently long and can produce a red-tilted scalar power spectrum due to
slow-roll violations. The robustness of these properties is confirmed by
conducting our analysis on three other models of hybrid-type inflation in
various framework: "smooth" and "shifted" inflation in SUSY and SUGRA, and
"radion assisted" gauge inflation. A high percentage of successful inflation
for smooth hybrid inflation (up to 80%) is observed.


title: Vortex solitons in dipolar Bose-Einstein Condensates

abstract:
  We predict solitary vortices in quasi-planar condensates of dipolar atoms,
polarized parallel to the confinement direction, with the effective sign of the
dipole-dipole interaction inverted by means of a rapidly rotating field. Energy
minima corresponding to vortex solitons with topological charges ${% \ell}=1$
and 2 are predicted for moderately strong dipole-dipole interaction, using an
axisymmetric Gaussian ansatz. The stability of the solitons with $\ell =1$ is
confirmed by full 3D simulations, whereas their counterparts with $\ell =2$ are
found to be unstable against splitting into a set of four fragments
(quadrupole).


title: Topology of moduli spaces of tropical curves with marked points

abstract:
  In this paper we study topology of moduli spaces of tropical curves of genus
$g$ with $n$ marked points. We view the moduli spaces as being imbedded in a
larger space, which we call the {\it moduli space of metric graphs with $n$
marked points.} We describe the shrinking bridges strong deformation
retraction, which leads to a substantial simplification of all these moduli
spaces. In the rest of the paper, that reduction is used to analyze the case of
genus 1. The corresponding moduli space is presented as a quotient space of a
torus with respect to the conjugation ${\mathbb Z}_2$-action; and furthermore,
as a homotopy colimit over a simple diagram. The latter allows us to compute
all Betti numbers of that moduli space with coefficients in ${\mathbb Z}_2$.


title:
A three dimensional object point process for detection of cosmic
  filaments

abstract:
  We propose to apply an object point process to automatically delineate
filaments of the large-scale structure in redshift catalogues. We illustrate
the feasibility of the idea on an example of the recent 2dF Galaxy Redshift
Survey, describe the procedure, and characterise the results.


title: Proposed Bell experiment with genuine energy-time entanglement

abstract:
  Franson's Bell experiment with energy-time entanglement [Phys. Rev. Lett. 62,
2205 (1989)] does not rule out all local hidden variable models. This defect
can be exploited to compromise the security of Bell inequality-based quantum
cryptography. We introduce a novel Bell experiment using genuine energy-time
entanglement, based on a novel interferometer, which rules out all local hidden
variable models. The scheme is feasible with actual technology.


title: Transparent connections over negatively curved surfaces

abstract:
  Let $(M,g)$ be a closed oriented negatively curved surface. A unitary
connection on a Hermitian vector bundle over $M$ is said to be transparent if
its parallel transport along the closed geodesics of $g$ is the identity. We
study the space of such connections modulo gauge and we prove a classification
result in terms of the solutions of certain PDE that arises naturally in the
problem. We also show a local uniqueness result for the trivial connection and
that there is a transparent SU(2)-connection associated to each meromorphic
function on $M$.


title: Coronal activity with XMM-Newton and Chandra

abstract:
  XMM-Newton and Chandra have greatly deepened our knowledge of stellar coronae
giving access to a variety of new diagnostics such that nowadays a review of
stellar X-ray astronomy necessarily must focus on a few selected topics.
Attempting to provide a limited but representative overview of recent
discoveries I discuss three subjects: the solar-stellar connection, the nature
of coronae in limiting regimes of stellar dynamos, and "hot topics" on X-ray
emission from pre-main sequence stars.


title: Depth estimation of the Large and Small Magellanic Clouds

abstract:
  We used the red clump stars from the photometric data of the Optical
Gravitational Lensing Experiment(OGLE II) survey and the Magellanic Cloud
Photometric Survey (MCPS) for both the Clouds to estimate the depth.The
observed dispersion in the magnitude and colour distribution of red clump stars
is used to estimate the depth, after correcting for population effects,
internal reddening within the Clouds and photometric errors.The observed
dispersion due to the line of sight depth ranges from 0.023 mag to 0.45 mag (a
depth of 500 pc to 10.4 kpc) for LMC and from 0.025 to 0.34 magnitude(a depth
of 670 pc to 9.53 kpc).The depth profile of the LMC bar indicates that it is
flared.The average depth in the bar region is 4.0$\pm$1.4 kpc. The northern
disk is found to have depth(4.17$\pm$0.97 kpc)larger than the southern part of
the disk (2.63$\pm$0.8kpc).There is no indication of depth variation between
the eastern and the western disk.The average depth for the disk is 3.44$\pm$
1.16 kpc.In the case of SMC, the bar depth(4.90$\pm$1.23 kpc)and the disk depth
(4.23$\pm$1.48kpc)are found to be within the standard deviations.A prominent
feature in the SMC is the increase in depth near the optical center.The large
dispersions estimated for the LMC bar and the northern disk suggest that the
LMC either has large depth and/or different stellar populations in these
regions.The halo of the LMC(using RR Lyrae stars)is found to have larger depth
compared to the disk/bar,which supports the existence of an inner halo for the
LMC.On the other hand, the estimated depths for the halo(RR Lyrae stars)and
disk are found to be similar,for the SMC bar region. Thus,increased depth and
enhanced stellar as well as HI density near the optical center suggests that
the SMC may have a bulge.


title: Tetraquark spectroscopy

abstract:
  A complete classification of tetraquark states in terms of the spin-flavor,
color and spatial degrees of freedom was constructed. The permutational
symmetry properties of both the spin-flavor and orbital parts of the
quark-quark and antiquark-antiquark subsystems are discussed. This complete
classification is general and model-independent, and is useful both for
model-builders and experimentalists. The total wave functions are also
explicitly constructed in the hypothesis of ideal mixing; this basis for
tetraquark states will enable the eigenvalue problem to be solved for a
definite dynamical model. This is also valid for diquark-antidiquark models,
for which the basis is a subset of the one we have constructed. An evaluation
of the tetraquark spectrum is obtained from the Iachello mass formula for
normal mesons, here generalized to tetraquark systems. This mass formula is a
generalizazion of the Gell-Mann Okubo mass formula, whose coefficients have
been upgraded by means of the latest PDG data.
  The ground state tetraquark nonet was identified with $f_{0}(600)$,
$\kappa(800)$, $f_{0}(980)$, $a_{0}(980)$. The mass splittings predicted by
this mass formula are compared to the KLOE, Fermilab E791 and BES experimental
data. The diquark-antidiquark limit was also studied.


title: Moduli spaces of metric graphs of genus 1 with marks on vertices

abstract:
  In this paper we study homotopy type of certain moduli spaces of metric
graphs. More precisely, we show that the spaces $MG_{1,n}^v$, which parametrize
the isometry classes of metric graphs of genus 1 with $n$ marks on vertices are
homotopy equivalent to the spaces $TM_{1,n}$, which are the moduli spaces of
tropical curves of genus 1 with $n$ marked points. Our proof proceeds by
providing a sequence of explicit homotopies, with key role played by the
so-called scanning homotopy. We conjecture that our result generalizes to the
case of arbitrary genus.


title:
Operator theoretic methods for the eigenvalue counting function in
  spectral gaps

abstract:
  Using the notion of spectral flow, we suggest a simple approach to various
asymptotic problems involving eigenvalues in the gaps of the essential spectrum
of self-adjoint operators. Our approach uses some elements of the spectral
shift function theory. Using this approach, we provide generalisations and
streamlined proofs of two results in this area already existing in the
literature. We also give a new proof of the generalised Birman-Schwinger
principle.


title: Measurement of CP asymmetries in $B^0 \to K^0\pi^0$ decays

abstract:
  We report measurements of CP violation parameters in $B^0 \to K^0 \pi^0$
decays based on a data sample of $657 \times 10^6 B\bar{B}$ pairs collected
with the Belle detector at the KEKB $e^+ e^-$ asymmetric-energy collider. We
use $B^0 \to K^0_S \pi^0$ decays for both mixing-induced and direct $CP$
violating asymmetry measurements and $B^0 \to K^0_L \pi^0$ decays for the
direct CP violation measurement. The CP violation parameters obtained are $\sin
2 \phi_1^{\rm eff} = +0.67 \pm 0.31{(stat)} \pm 0.08 {(syst)}$ and
$\mathcal{A}_{K^0 \pi^0} = +0.14 \pm 0.13{(stat)} \pm 0.06 {(syst)}$. The
branching fraction of $B^0 \to K^0 \pi^0$ decay is measured to be
$\mathcal{B}(B^0 \to K^0 \pi^0) = (8.7\pm0.5 (\rm{stat.})\pm0.6
(\rm{syst.}))\times 10^{-6}$. The observed $\mathcal{A}_{K^0 \pi^0}$ value
differs by 1.9 standard deviations from the value expected from an isospin sum
rule.


title:
Moduli spaces of tropical curves of higher genus with marked points and
  homotopy colimits

abstract:
  The main characters of this paper are the moduli spaces $TM_{g,n}$ of
rational tropical curves of genus $g$ with $n$ marked points, with $g\geq 2$.
We reduce the study of the homotopy type of these spaces to the analysis of
compact spaces $X_{g,n}$, which in turn possess natural representations as a
homotopy colimits of diagrams of topological spaces over combinatorially
defined generalized simplicial complexes $\Delta_g$, with the latter being
interesting on their own right.
  We use these homotopy colimit representations to describe a CW complex
decomposition for each $X_{g,n}$. Furthermore, we use these developments,
coupled with some standard tools for working with homotopy colimits, to perform
an in-depth analysis of special cases of genus 2 and 3, gaining a complete
understanding of the moduli spaces $X_{2,0}$, $X_{2,1}$, $X_{2,2}$, and
$X_{3,0}$, as well as a partial understanding of other cases, resulting in
several open questions and in further conjectures.


title: Quantum computing with trapped ions

abstract:
  Quantum computers hold the promise to solve certain computational task much
more efficiently than classical computers. We review the recent experimental
advancements towards a quantum computer with trapped ions. In particular,
various implementations of qubits, quantum gates and some key experiments are
discussed. Furthermore, we review some implementations of quantum algorithms
such as a deterministic teleportation of quantum information and an error
correction scheme.


title:
Evolution of newly formed dust in Population III supernova remnants and
  its impact on the elemental composition of Population II.5 stars

abstract:
  We investigate the evolution of dust formed in Population III supernovae
(SNe) by considering its transport and processing by sputtering within the SN
remnants (SNRs). We find that the fates of dust grains within SNRs heavily
depend on their initial radii $a_{\rm ini}$. For Type II SNRs expanding into
the ambient medium with density of $n_{\rm H,0} = 1$ cm$^{-3}$, grains of
$a_{\rm ini} < 0.05$ $\mu$m are detained in the shocked hot gas and are
completely destroyed, while grains of $a_{\rm ini} > 0.2$ $\mu$m are injected
into the surrounding medium without being destroyed significantly. Grains with
$a_{\rm ini}$ = 0.05-0.2 $\mu$m are finally trapped in the dense shell behind
the forward shock. We show that the grains piled up in the dense shell enrich
the gas up to 10$^{-6}-10^{-4}$ $Z_\odot$, high enough to form low-mass stars
with 0.1-1 $M_\odot$. In addition, [Fe/H] in the dense shell ranges from -6 to
-4.5, which is in good agreement with the ultra-metal-poor stars with [Fe/H] <
-4. We suggest that newly formed dust in a Population III SN can have great
impacts on the stellar mass and elemental composition of Population II.5 stars
formed in the shell of the SNR.


title:
Metamaterials for light rays: ray optics without wave-optical analog in
  the ray-optics limit

abstract:
  Volumes of sub-wavelength electromagnetic elements can act like homogeneous
materials: metamaterials. In analogy, sheets of optical elements such as prisms
can act ray-optically like homogeneous sheet materials. In this sense, such
sheets can be considered to be metamaterials for light rays (METATOYs).
METATOYs realize new and unusual transformations of the directions of
transmitted light rays. We study here, in the ray-optics and scalar-wave
limits, the wave-optical analog of such transformations, and we show that such
an analog does not always exist. Perhaps, this is the reason why many of the
ray-optical possibilities offered by METATOYs have never before been
considered.


title: Extensions of profinite duality groups

abstract:
  We show that the class of profinite duality groups is closed under group
extensions provided that the kernel satisfies some finiteness condition. This
extends earlier results of Pletch and of Wingberg.


title: Ruin probabilities under general investments and heavy-tailed claims

abstract:
  In this paper we study the asymptotic decay of finite time ruin probabilities
for an insurance company that faces heavy-tailed claims, uses predictable
investment strategies and makes investments in risky assets whose prices evolve
according to quite general semimartingales. We show that the ruin problem
corresponds to determining hitting probabilities for the solution to a randomly
perturbed stochastic integral equation. We derive a large deviation result for
the hitting probabilities that holds uniformly over a family of semimartingales
and show that this result gives the asymptotic decay of finite time ruin
probabilities under arbitrary investment strategies, including optimal
investment strategies.


title: Quantum resonances in an atom-optical delta-kicked harmonic oscillator

abstract:
  Under certain conditions, the quantum delta-kicked harmonic oscillator
displays quantum resonances. We consider an atom-optical realization of the
delta-kicked harmonic oscillator, and present a theoretical discussion of the
quantum resonances that could be observed in such a system. Having outlined our
model of the physical system we derive the values at which quantum resonances
occur and relate these to potential experimental parameters. We discuss the
observable effects of the quantum resonances, using the results of numerical
simulations. We develop a physical explanation for the quantum resonances based
on symmetries shared between the classical phase space and the
quantum-mechanical time evolution operator. We explore the evolution of
coherent states in the system by reformulating the dynamics in terms of a
mapping over an infinite, two-dimensional set of coefficients, from which we
derive an analytic expression for the evolution of a coherent state at quantum
resonance.


title: Polarized thermal emission by thin metal wires

abstract:
  We report new measurements of the linear polarization of thermal radiation
emitted by incandescent thin tungsten wires, with thicknesses ranging from five
to hundred microns. Our data show very good agreement with theoretical
predictions, based on Drude-type fits to measured optical properties of
tungsten.


title: Reversable heat flow through the carbon nanotube junctions

abstract:
  Microscopic mechanisms of externally controlled reversable heat flow through
the carbon nanotube junctions (NJ) are studied theoretically. Our model
suggests that the heat is transfered along the tube section ${\cal T}$ by
electrons ($e$) and holes ($h$) moving ballistically in either in parallel or
in opposite directions and accelerated by the bias source-drain voltage $V_{\rm
SD}$ (Peltier effect). We compute the Seebeck coefficient $\alpha $, electric
$\sigma$ and thermal $\kappa$ conductivities and find that their magnitudes
strongly depend on $V_{\rm SD}$ and $V_{\rm G}$. The sign reversal of $\alpha$
versus the sign of $V_{\rm G}$ formerly observed experimentally is interpreted
in this work in terms of so-called chiral tunneling phenomena (Klein paradox).


title: The internal-environment model of the Stern-Gerlach experiment

abstract:
  The standard interpretation of the Stern-Gerlach experiment assumes that the
atomic center-of-mass plays the role of "quantum apparatus" for the atomic
spin. Following a recent, decoherence-based, model fitting with this
interpretation, we investigate whether or not such model can be constructed.
Our conclusions are somewhat surprising: only if the screen capturing the atoms
in the experiment brings the information about the atomic-nucleus
center-of-mass, one may construct the model desired. The nucleus $CM$ system is
monitored by the nucleus "relative system ($R$)". There appear the effective
(the electrons-mediated) interaction between $CM$ and $R$ that is possibly
responsible for decoherence. For larger atoms, the interaction scales as $Z^2$
($Z$ is the "atomic number"), being totally independent on the atomic mass. The
interaction selects the $CM$-wave-packet states as the approximate pointer
basis. Interestingly enough, the model stems nonoccurrence of decoherence due
to the internal environment for the larger systems (such as the macromolecules
and the macroscopic systems). Certainly, disproving this model (e.g. in an
experiment) stems the active role of the screen, which becomes responsible for
the "$CM$ + spin"-state "reduction" ("collapse"), i.e. for the irreversible
retrieval of the classical information from the quantum world.


title: Double parton correlations in perturbative QCD

abstract:
  This talk brings attention to what is knowable from perturbative QCD theory
on two-parton distribution functions in the light of CDF measuruments of the
inclusive cross section for double parton scattering.


title:
Vacuum solutions with nontrivial boundaries for the
  Einstein-Gauss-Bonnet theory

abstract:
  The classification of certain class of static solutions for the
Einstein-Gauss-Bonnet theory in vacuum is presented. The spacelike section of
the class of metrics under consideration is a warped product of the real line
with a nontrivial base manifold. For arbitrary values of the Gauss-Bonnet
coupling, the base manifold must be Einstein with an additional scalar
restriction. The geometry of the boundary can be relaxed only when the
Gauss-Bonnet coupling is related with the cosmological and Newton constants, so
that the theory admits a unique maximally symmetric solution. This additional
freedom in the boundary metric allows the existence of three main branches of
geometries in the bulk, containing new black holes and wormholes in vacuum.


title: Shear state of freely evolving granular gases

abstract:
  Hydrodynamic equations are used to identify the final state reached by a
freely evolving granular gas above but close to its shear instability. The
theory predicts the formation of a two bands shear state with a steady density
profile. There is a modulation between temperature and density profiles as a
consequence of the energy balance, the density fluctuations remaining small,
without producing clustering. Moreover, the time dependence of the velocity
field can be scaled out with the squared root of the average temperature of the
system. The latter follows the Haff law, but with an effective cooling rate
that is smaller than that of the free homogeneous state. The theoretical
predictions are compared with numerical results for inelastic hard disks
obtained by using the direct Monte Carlo simulation method, and a good
agreement is obtained for low inelasticity.


title:
Law of the Iterated Logarithm for the random walk on the infinite
  percolation cluster

abstract:
  We show that random walks on the infinite supercritical percolation clusters
in Z^d satisfy the usual Law of the Iterated Logarithm. The proof combines
Barlow's Gaussian heat kernel estimates and the ergodicity of the random walk
on the environment viewed from the random walker as derived by Berger and
Biskup.


title: Representing an element in F_q[t] as the sum of two irreducibles

abstract:
  A monic polynomial in F_q[t] of degree n over a finite field F_q of odd
characteristic can be written as the sum of two irreducible monic elements in
F_q[t] of degrees n and n-1 if q is larger than a bound depending only on n.
The main tool is a sufficient condition for simultaneous primality of two
polynomials in one variable x with coefficients in F_q[t].


title:
Time resolution of a Thick Gas Electron Multiplier (THGEM) - based
  detector

abstract:
  The time resolution of a double-stage Thick-GEM (THGEM) detector was measured
with UV-photons and relativistic electrons. The photon detector, with
semitransparent- or reflective-photocathode yielded time resolution of about
8-10ns RMS for single photoelectrons and 0.5-1ns RMS for few-hundred
photoelectrons per photon-pulse. Time resolution of about 10ns RMS was recorded
for relativistic electrons from a 106Ru source.


title:
Production of a Z boson and a photon via a Randall-Sundrum-type graviton
  at the Large Hadron Collider

abstract:
  In extra dimensional models with Kaluza-Klein graviton states that are well
separated in mass, such states may be observed as resonances in collider
experiments. We extend previous works on such scenarios by considering the
one-loop resonant production of a Z boson in association with a photon. We find
the production rate to be negligible in conservative scenarios, and
sufficiently small for observation to be very difficult even for reasonable
luminosity in less conservative scenarios.


title: Bogomol'nyi Bounds for Gravitational Cosmic Strings

abstract:
  We present a new method for finding lower bounds on the energy of topological
cosmic string solutions in gravitational field theories. This new method
produces bounds that are valid over the entire space of solutions, unlike the
traditional approach, where the bounds obtained are only valid for
cylindrically symmetric solutions. This method is shown to be a generalisation
of the well-known Bogomol'nyi procedure for non-gravitational theories and as
such, it can be used to find gravitational Bogomol'nyi bounds for models
wherever the traditional Bogomol'nyi procedure can be applied in the
non-gravitational limit. Furthermore, this method yields Bogomol'nyi equations
that do not rule out the existence of asymmetric bound-saturating solutions.


title: Accurate numerical solution to the finite-size Dicke model

abstract:
  By using extended bosonic coherent states, a new technique to solve the Dicke
model exactly is proposed in the numerical sense. The accessible system size is
two orders of magnitude higher than that reported in literature. Finite-size
scaling for several observables, such as the ground-state energy, Berry phase,
and concurrence are analyzed. The existing discrepancy for the scaling exponent
of the concurrence is reconciled.


title: Automorphic orbits in free groups: words versus subgroups

abstract:
  We show that the following problems are decidable in a rank 2 free group F_2:
does a given finitely generated subgroup H contain primitive elements? and does
H meet the orbit of a given word u under the action of G, the group of
automorphisms of F_2? Moreover, decidability subsists if we allow H to be a
rational subset of F_2, or alternatively if we restrict G to be a rational
subset of the set of invertible substitutions (a.k.a. positive automorphisms).
In higher rank, we show the decidability of the following weaker problem: given
a finitely generated subgroup H, a word u and an integer k, does H contain the
image of u by some k-almost bounded automorphism? An automorphism is k-almost
bounded if at most one of the letters has an image of length greater than k.


title: Small counts in the infinite occupancy scheme

abstract:
  The paper is concerned with the classical occupancy scheme with infinitely
many boxes, in which $n$ balls are thrown independently into boxes $1,2,...$,
with probability $p_j$ of hitting the box $j$, where $p_1\geq p_2\geq...>0$ and
$\sum_{j=1}^\infty p_j=1$. We establish joint normal approximation as
$n\to\infty$ for the numbers of boxes containing $r_1,r_2,...,r_m$ balls,
standardized in the natural way, assuming only that the variances of these
counts all tend to infinity. The proof of this approximation is based on a
de-Poissonization lemma. We then review sufficient conditions for the variances
to tend to infinity. Typically, the normal approximation does not mean
convergence. We show that the convergence of the full vector of $r$-counts only
holds under a condition of regular variation, thus giving a complete
characterization of possible limit correlation structures.


title: Freezing a Coherent Field Growth in a Cavity by Quantum Zeno Effect

abstract:
  We have frozen the coherent evolution of a field in a cavity by repeated
measurements of its photon number. We use circular Rydberg atoms dispersively
coupled to the cavity mode for an absorption-free photon counting. These
measurements inhibit the growth of a Field injected in the cavity by a
classical source. This manifestation of the Quantum Zeno effect illustrates the
back action of the photon number determination onto the Field phase. The
residual growth of the Field can be seen as a random walk of its amplitude in
the two-dimensional phase space. This experiment sheds light onto the
measurement process and opens perspectives for active quantum feedback.


title: Fractional embeddings and stochastic time

abstract:
  As a model problem for the study of chaotic Hamiltonian systems, we look for
the effects of a long-tail distribution of recurrence times on a fixed
Hamiltonian dynamics. We follow Stanislavsky's approach of Hamiltonian
formalism for fractional systems. We prove that his formalism can be retrieved
from the fractional embedding theory. We deduce that the fractional Hamiltonian
systems of Stanislavsky stem from a particular least action principle, said
causal. In this case, the fractional embedding becomes coherent.


title: Supersymmetry: The Final Countdown

abstract:
  There is hope that the Large Hadron Collider (LHC) at CERN will tell us about
the fate of supersymmetry at the TeVscale. Therefore we might try to identify
our expectations for the discovery of SUSY, especially in the first years of
operation of this machine. In this talk we shall concentrate on the simplest
SUSY scheme: the MSSM with SUSY broken in a hidden sector mediated by
interactions of gravitational strength (gravity-, modulus and
mirage-mediation). Such a situation might be favoured in a large class of
string inspired models. There is a good chance to identify such simple schemes
by knowing the properties of the gaugino mass spectrum such as the
gluino/neutralino mass ratios.


title:
ASTEP South: An Antarctic Search for Transiting Planets around the
  celestial South pole

abstract:
  ASTEP South is the first phase of the ASTEP project that aims to determine
the quality of Dome C as a site for future photometric searches for transiting
exoplanets and discover extrasolar planets from the Concordia base in
Antarctica. ASTEP South consists of a front-illuminated 4k x 4k CCD camera, a
10 cm refractor, and a simple mount in a thermalized enclosure. A double-glass
window is used to reduce temperature variations and its accompanying turbulence
on the optical path. The telescope is fixed and observes a 4 x 4 square degrees
field of view centered on the celestial South pole. With this design, A STEP
South is very stable and observes with low and constant airmass, both being
important issues for photometric precision. We present the project, we show
that enough stars are present in our field of view to allow the detection of
one to a few transiting giant planets, and that the photometric precision of
the instrument should be a few mmag for stars brighter than magnitude 12 and
better than 10 mmag for stars of magnitude 14 or less.


title: Sedimentation-consolidation of a double porosity material

abstract:
  This paper studies the sedimentation-consolidation of a double porosity
material, such as lumpy clay. Large displacements and finite strains are
accounted for in a multidimensional setting. Fundamental equations are derived
using a phenomenological approach and non-equilibrium thermodynamics, as set
out by Coussy [Coussy, Poromechanics, Wiley, Chichester, 2004]. These equations
particularise to three non-linear partial differential equations in one
dimensional context. Numerical implementation in a finite element code is
currently being undertaken.


title: Correction. SDEs with oblique reflections on nonsmooth domains

abstract:
  Correction to The Annals of Probability 21 (1993) 554--580
[http://projecteuclid.org/euclid.aop/1176989415]


title: N-Qubit W States are Determined by their Bipartite Marginals

abstract:
  We prove that the most general W class of N-qubit states are uniquely
determined among arbitrary states (pure or mixed) by just their bipartite
reduced density matrices. Moreover, if we consider only pure states, then (N-1)
of them are shown to be sufficient.


title: Content Sharing for Mobile Devices

abstract:
  The miniaturisation of computing devices has seen computing devices become
increasingly pervasive in society. With this increased pervasiveness, the
technologies of small computing devices have also improved. Mobile devices are
now capable of capturing various forms of multimedia and able to communicate
wirelessly using increasing numbers of communication techniques. The owners and
creators of local content are motivated to share this content in ever
increasing volume; the conclusion has been that social networks sites are
seeing a revolution in the sharing of information between communities of
people. As load on centralised systems increases, we present a novel
decentralised peer-to-peer approach dubbed the Market Contact Protocol (MCP) to
achieve cost effective, scalable and efficient content sharing using
opportunistic networking (pocket switched networking), incentive,
context-awareness, social contact and mobile devices. Within the report we
describe how the MCP is simulated with a superimposed geographic framework on
top of the JiST (Java in Simulation Time) framework to evaluate and measure its
capability to share content between massively mobile peers. The MCP is shown in
conclusion to be a powerful means by which to share content in a massively
mobile ad-hoc environment.


title: Flow Equation for Supersymmetric Quantum Mechanics

abstract:
  We study supersymmetric quantum mechanics with the functional RG formulated
in terms of an exact and manifestly off-shell supersymmetric flow equation for
the effective action. We solve the flow equation nonperturbatively in a
systematic super-covariant derivative expansion and concentrate on systems with
unbroken supersymmetry. Already at next-to-leading order, the energy of the
first excited state for convex potentials is accurately determined within a 1%
error for a wide range of couplings including deeply nonperturbative regimes.


title:
Recent progress in open quantum systems: Non-Gaussian noise and
  decoherence in fermionic systems

abstract:
  We review our recent contributions to two topics that have become of interest
in the field of open, dissipative quantum systems: non-Gaussian noise and
decoherence in fermionic systems. Decoherence by non-Gaussian noise, i.e. by an
environment that cannot be approximated as a bath of harmonic oscillators, is
important in nanostructures (e.g. qubits) where there might be strong coupling
to a small number of fluctuators. We first revisit the pedagogical example of
dephasing by classical telegraph noise. Then we address two models where the
quantum nature of the noise becomes essential: "quantum telegraph noise" and
dephasing by electronic shot noise. In fermionic systems, many-body aspects and
the Pauli principle have to be taken care of when describing the loss of phase
coherence. This is relevant in electronic quantum transport through metallic
and semiconducting structures. Specifically, we recount our recent results
regarding dephasing in a chiral interacting electron liquid, as it is realized
in the electronic Mach-Zehnder interferometer. This model can be solved
employing the technique of bosonization as well as a physically transparent
semiclassical method.


title:
Multistep greedy algorithm identifies community structure in real-world
  and computer-generated networks

abstract:
  We have recently introduced a multistep extension of the greedy algorithm for
modularity optimization. The extension is based on the idea that merging l
pairs of communities (l>1) at each iteration prevents premature condensation
into few large communities. Here, an empirical formula is presented for the
choice of the step width l that generates partitions with (close to) optimal
modularity for 17 real-world and 1100 computer-generated networks. Furthermore,
an in-depth analysis of the communities of two real-world networks (the
metabolic network of the bacterium E. coli and the graph of coappearing words
in the titles of papers coauthored by Martin Karplus) provides evidence that
the partition obtained by the multistep greedy algorithm is superior to the one
generated by the original greedy algorithm not only with respect to modularity
but also according to objective criteria. In other words, the multistep
extension of the greedy algorithm reduces the danger of getting trapped in
local optima of modularity and generates more reasonable partitions.

categories: cs.DS cond-mat.dis-nn physics.soc-ph q-bio.MN q-bio.QM


title: The edge-flipping group of a graph

abstract:
  Let $X=(V,E)$ be a finite simple connected graph with $n$ vertices and $m$
edges. A configuration is an assignment of one of two colors, black or white,
to each edge of $X.$ A move applied to a configuration is to select a black
edge $\epsilon\in E$ and change the colors of all adjacent edges of $\epsilon.$
Given an initial configuration and a final configuration, try to find a
sequence of moves that transforms the initial configuration into the final
configuration. This is the edge-flipping puzzle on $X,$ and it corresponds to a
group action. This group is called the edge-flipping group $\mathbf{W}_E(X)$ of
$X.$ This paper shows that if $X$ has at least three vertices,
$\mathbf{W}_E(X)$ is isomorphic to a semidirect product of
$(\mathbb{Z}/2\mathbb{Z})^k$ and the symmetric group $S_n$ of degree $n,$ where
$k=(n-1)(m-n+1)$ if $n$ is odd, $k=(n-2)(m-n+1)$ if $n$ is even, and
$\mathbb{Z}$ is the additive group of integers.


title: Finite temperature vortex dynamics in Bose Einstein condensates

abstract:
  We study the decay of vortices in Bose-Einstein condensates at finite
temperatures by means of the Zaremba Nikuni Griffin formalism, in which the
condensate is modelled by a Gross Pitaevskiiequation, which is coupled to a
Boltzmann kinetic equation for the thermal cloud. At finite temperature, an
off-centred vortex in a harmonically trapped pancake shaped condensate decays
by spiralling out towards the edge of the condensate. This decay, which depends
heavily on temperature and atomic collisions, agrees with that predicted by the
Hall Vinen phenomenological model of friction force, which is used to describe
quantised vorticity in superfluid systems. Our result thus clarifies the
microscopic origin of the friction and provides an ab initio determination of
its value.


title: Unambiguous comparison of unitary channels

abstract:
  We address the problem of unambiguous comparison of a pair of unknown qudit
unitary channels. Using the framework of process positive operator valued
measures (PPOVM) we characterize all solutions and identify the optimal ones.
We prove that the entanglement is the key ingredient in designing the optimal
experiment for comparison of unitary channels. Without entanglement the
optimality can not be achieved. The proposed scheme is also experimentally
feasible.


title: The Modultional Instability for a Generalized KdV Equation

abstract:
  We study the spectral stability of a family of periodic standing wave
solutions to the generalized KdV (g-KdV) in a neighborhood of the origin in the
spectral plane using what amounts to a rigorous Whitham modulation theory
calculation. In particular we are interested in understanding the role played
by the null directions of the linearized operator in the stability of the
traveling wave to perturbations of long wavelength.
  A study of the normal form of the characteristic polynomial of the monodromy
map (the periodic Evan's function) in a neighborhood of the origin in the
spectral plane leads to two different instability indices. The first index
counts modulo 2 the total number of periodic eigenvalues on the real axis. This
index is a generalization of the one which governs the stability of the
solitary wave. The second index provides a necessary and sufficient condition
for the existence of a long-wavelength instability. This index is essentially
the quantity calculated by Haragus and Kapitula in the small amplitude limit.
Both of these quantities can be expressed in terms of the map between the
constants of integration for the ordinary differential equation defining the
traveling waves and the conserved quantities of the partial differential
equation. These two indices together provide a good deal of information about
the spectrum of the linearized operator.
  We sketch the connection of this calculation to a study of the linearized
operator - in particular we perform a perturbation calculation in terms of the
Floquet parameter. This suggests geometric interpretations attached to the
vanishing of the modulational instability index previously mentioned.


title: Introduction to dissipation and decoherence in quantum systems

abstract:
  These lecture notes address an audience of physicists or mathematicians who
have been exposed to a first course in quantum mechanics. We start with a brief
discussion of the general "system-bath" paradigm of quantum dissipative
systems, analyze in some detail the simplest example of "pure dephasing" of a
two-level system, and review the basic concept of the density matrix. We then
treat the general dissipative time-evolution, introducing completely positive
maps, their relation to entanglement theory, and their Kraus decomposition.
Restricting ourselves to Markovian evolution, we discuss the Lindblad form of
master equations. The notes conclude with an overview of topics of current
interest that go beyond Lindblad Markov master equations. (These notes were
prepared for lectures delivered by F. Marquardt in October 2007 at the Langeoog
workshop of the SFB/TR 12, "Symmetries and Universality in Mesoscopic Systems")


title:
Experimental magnetic form factors in Co3V2O8: A combined study of ab
  initio calculations, magnetic Compton scattering and polarized neutron
  diffraction

abstract:
  We present a combination of ab initio calculations, magnetic Compton
scattering and polarized neutron experiments, which elucidate the density
distribution of unpaired electrons in the kagome staircase system Co3V2O8. Ab
initio wave functions were used to calculate the spin densities in real and
momentum space, which show good agreement with the respective experiments. It
has been found that the spin polarized orbitals are equally distributed between
the t2g and the eg levels for the spine (s) Co ions, while the eg orbitals of
the cross-tie (c) Co ions only represent 30% of the atomic spin density.
Furthermore, the results reveal that the magnetic moments of the cross-tie Co
ions, which are significantly smaller than those of the spine Co ions in the
zero-field ferromagnetic structure, do not saturate by applying an external
magnetic field of 2 T along the easy axis a, but that the increasing bulk
magnetization originates from induced magnetic moments on the O and V sites.
The refined individual magnetic moments are mu(Co_c)=1.54(4) mu_B,
mu(Co_s)=2.87(3) mu_B, mu(V)=0.41(4) mu_B, mu(O1)=0.05(5) mu_B, mu(O2)=0.35(5)
mu_B, and; mu(O3)=0.36(5) mu_B combining to the same macroscopic magnetization
value, which was previously only attributed to the Co ions.


title:
Eigenvector localization for random band matrices with power law band
  width

abstract:
  It is shown that certain ensembles of random matrices with entries that
vanish outside a band around the diagonal satisfy a localization condition on
the resolvent which guarantees that eigenvectors have strong overlap with a
vanishing fraction of standard basis vectors, provided the band width $W$
raised to a power $\mu$ remains smaller than the matrix size $N$. For a
Gaussian band ensemble, with matrix elements given by i.i.d. centered Gaussians
within a band of width $W$, the estimate $\mu \le 8$ holds.


title:
On ergodic transformations that are both weakly mixing and uniformly
  rigid

abstract:
  We examine some of the properties of uniformly rigid transformations, and
analyze the compatibility of uniform rigidity and (measurable) weak mixing
along with some of their asymptotic convergence properties. We show that on
Cantor space, there does not exist a finite measure-preserving, totally
ergodic, uniformly rigid transformation. We briefly discuss general group
actions and show that (measurable) weak mixing and uniform rigidity can coexist
in a more general setting.


title:
PHotometry Assisted Spectral Extraction (PHASE) and identification of
  SNLS supernovae

abstract:
  Aim: We present new extraction and identification techniques for supernova
(SN) spectra developed within the Supernova Legacy Survey (SNLS) collaboration.
  Method: The new spectral extraction method takes full advantage of
photometric information from the Canada-France-Hawai telescope (CFHT) discovery
and reference images by tracing the exact position of the supernova and the
host signals on the spectrogram. When present, the host spatial profile is
measured on deep multi-band reference images and is used to model the host
contribution to the full (supernova + host) signal. The supernova is modelled
as a Gaussian function of width equal to the seeing. A chi-square minimisation
provides the flux of each component in each pixel of the 2D spectrogram. For a
host-supernova separation greater than <~ 1 pixel, the two components are
recovered separately and we do not use a spectral template in contrast to more
standard analyses. This new procedure permits a clean extraction of the
supernova separately from the host in about 70% of the 3rd year ESO/VLT spectra
of the SNLS. A new supernova identification method is also proposed. It uses
the SALT2 spectrophotometric template to combine the photometric and spectral
data. A galaxy template is allowed for spectra for which a separate extraction
of the supernova and the host was not possible.
  Result: These new techniques have been tested against more standard
extraction and identification procedures. They permit a secure type and
redshift determination in about 80% of cases. The present paper illustrates
their performances on a few sample spectra.


title: Euclidean Quantum Mechanics and Universal Nonlinear Filtering

abstract:
  An important problem in applied science is the continuous nonlinear filtering
problem, i.e., the estimation of a Langevin state that is observed indirectly.
In this paper, it is shown that Euclidean quantum mechanics is closely related
to the continuous nonlinear filtering problem. The key is the configuration
space Feynman path integral representation of the fundamental solution of a
Fokker-Planck type of equation termed the Yau Equation of continuous-continuous
filtering. A corollary is the equivalence between nonlinear filtering problem
and a time-varying Schr\"odinger equation.


title:
Electronic structure and effects of dynamical electron correlation in
  ferromagnetic bcc-Fe, fcc-Ni and antiferromagnetic NiO

abstract:
  LDA+DMFT method in the framework of the iterative perturbation theory (IPT)
with full LDA Hamiltonian without mapping onto the effective Wannier orbitals.
We then apply this LDA+DMFT method to ferromagnetic bcc-Fe and fcc-Ni as a test
of transition metal, and to antiferromagnetic NiO as an example of transition
metal oxide. In Fe and Ni, the width of occupied 3d bands is narrower than
those in LDA and Ni 6eV satellite appears. In NiO, the resultant electronic
structure is of charge-transfer insulator type and the band gap is 4.3eV. These
results are in good agreement with the experimental XPS. The configuration
mixing and dynamical correlation effects play a crucial role in these results.


title: Generator coalgebras are not necessarily quasi-coFrobenius

abstract:
  We study the problem of whether a coalgebra that generates its category of
left (right) comodules is left (right) quasi-coFrobenius or not. We prove it
does not hold in general, by giving a method of constructing counterexamples.
This gives a negative answer to a question stated in \cite{kn:coalgen}. We also
prove it is true for monomial pointed coalgebras and we characterize the
quivers $Q$ such that $\Bbbk Q$ admits a monomial subcoalgebra that is left
(right) quasi-coFrobenius.


title:
Vector meson $\omega$-$\phi$ mixing and their form factors in light-cone
  quark model

abstract:
  The vector meson $\omega$-$\phi$ mixing is studied in two alternative
scenarios with different numbers of mixing angles, i.e., the one-mixing-angle
scenario and the two-mixing-angle scenario, in both the octect-singlet mixing
scheme and the quark flavor mixing scheme. Concerning the reproduction of
experimental data and the $Q^2$ behavior of transition form factors,
one-mixing-angle scenario in the quark flavor scheme performs better than that
in the octet-singlet scheme, while the two-mixing-angle scenario works well for
both mixing schemes. The difference between the two mixing angles in the
octet-singlet scheme is bigger than that in the quark flavor scheme.


title: Real and strongly real classes in finite linear groups

abstract:
  We classify the real and strongly real conjugacy classes in $GL_n(q)$,
$SL_n(q)$, $PGL_n(q)$, $PSL_n(q)$, and all quasi-simple covers of $PSL_n(q)$.
In each case we give a formula for the number of real, and the number of
strongly real, conjugacy classes.


title: Distillation of Liquid Xenon to Remove Krypton

abstract:
  A high performance distillation system to remove krypton from xenon was
constructed, and a purity level of Kr/Xe = $\sim 3 \times 10^{-12}$ was
achieved. This development is crucial in facilitating high sensitivity low
background experiments such as the search for dark matter in the universe.


title:
Magneto-thermal properties of the spin-s Heisenberg antiferromagnet on
  the cuboctahedron

abstract:
  We use the example of the cuboctahedron, a highly frustrated molecule with 12
sites, to study the approach to the classical limit. We compute magnetic
susceptibility, specific heat, and magnetic cooling rate at high magnetic
fields and low temperatures for different spin quantum numbers s. Remarkably
big deviations of these quantities from their classical counterparts are
observed even for values of s which are usually considered to be almost
classical.


title: IGR J18483-0311: a new intermediate supergiant fast X-ray transient

abstract:
  IGR J18483-0311 is a high-mass X-ray binary recently discovered by INTEGRAL.
Its periodic fast X-ray transient activity and its position in the Corbet
diagram - although ambiguous - led to the conclusion that the source was a
likely Be/X-ray binary (BeXB), even if a supergiant fast X-ray transient (SFXT)
nature could not be excluded. We aimed at identifying the companion star of IGR
J18483-0311 to discriminate between the BeXB and the SFXT nature of the source.
Optical and near-infrared photometry, as well as near-infrared spectroscopy of
the companion star were performed to identify its spectral type. We also
assembled and fitted its broad-band spectral energy distribution to derive its
physical parameters. We show that the companion star of IGR J18483-0311 is an
early-B supergiant, likely a B0.5Ia, and that its distance is about 3-4 kpc.
The early-B supergiant nature of its companion star, as well as its fast X-ray
transient activity point towards an SFXT nature of IGR J18483-0311.
Nevertheless, the long duration and the periodicity of its outbursts, as well
as its high level of quiescence, are consistent with IGR J18483-0311 being an
intermediate SFXT, in between classical supergiant X-ray binaries (SGXBs)
characterised by small and circular orbits, and classical SFXTs with large and
eccentric orbits.


title:
Shor's factorization algorithm with a single control qubit and
  imperfections

abstract:
  We formulate and numerically simulate the single control qubit Shor algorithm
for the case of static imperfections induced by residual couplings between
qubits. This allows us to study the accuracy of Shor's algorithm with respect
to these imperfections using numerical simulations of realistic quantum
computations with up to $n_q=18$ computational qubits allowing to factor
numbers up to N=205193. We confirm that the algorithm remains operational up to
a critical coupling strength $\epsilon_c$ which drops only polynomially with
$\log_2 N$. The obtained numerical dependence of $\epsilon_c$ on $\log_2 N$ is
in a good agreement with the analytical estimates that allows to obtain the
scaling for functionality of Shor's algorithm on realistic quantum computers
with a large number of qubits.


title: The Gaia satellite: a tool for Emission Line Stars and Hot Stars

abstract:
  The Gaia satellite will be launched at the end of 2011. It will observe at
least 1 billion stars, and among them several million emission line stars and
hot stars. Gaia will provide parallaxes for each star and spectra for stars
till V magnitude equal to 17. After a general description of Gaia, we present
the codes and methods, which are currently developed by our team. They will
provide automatically the astrophysical parameters and spectral classification
for the hot and emission line stars in the Milky Way and other close Local
Group galaxies such as the Magellanic Clouds.


title: Community structures and role detection in music networks

abstract:
  We analyze the existence of community structures in two different social
networks obtained from similarity and collaborative features between musical
artists. Our analysis reveals some characteristic organizational patterns and
provides information about the driving forces behind the growth of the
networks. In the similarity network, we find a strong correlation between
clusters of artists and musical genres. On the other hand, the collaboration
network shows two different kinds of communities: rather small structures
related to music bands and geographic zones, and much bigger communities built
upon collaborative clusters with a high number of participants related through
the period the artists were active. Finally, we detect the leading artists
inside their corresponding communities and analyze their roles in the network
by looking at a few topological properties of the nodes.


title:
Fermionization of a strongly interacting Bose-Fermi mixture in a
  one-dimensional harmonic trap

abstract:
  We consider a strongly interacting one-dimensional (1D) Bose-Fermi mixture
confined in a harmonic trap. It consists of a Tonks-Girardeau (TG) gas (1D Bose
gas with repulsive hard-core interactions) and of a non-interacting Fermi gas
(1D spin-aligned Fermi gas), both species interacting through hard-core
repulsive interactions. Using a generalized Bose-Fermi mapping, we determine
the exact particle density profiles, momentum distributions and behaviour of
the mixture under 1D expansion when opening the trap. In real space, bosons and
fermions do not display any phase separation: the respective density profiles
extend over the same region and they both present a number of peaks equal to
the total number of particles in the trap. In momentum space the bosonic
component has the typical narrow TG profile, while the fermionic component
shows a broad distribution with fermionic oscillations at small momenta. Due to
the large boson-fermion repulsive interactions, both the bosonic and the
fermionic momentum distributions decay as $C p^{-4}$ at large momenta, like in
the case of a pure bosonic TG gas. The coefficient $C$ is related to the
two-body density matrix and to the bosonic concentration in the mixture. When
opening the trap, both momentum distributions "fermionize" under expansion and
turn into that of a Fermi gas with a particle number equal to the total number
of particles in the mixture.


title: The WFI Halpha spectroscopic survey

abstract:
  This document presents the results from our spectroscopic survey of Halpha
emitters in galactic and SMC open clusters with the ESO Wide Field Imager in
its slitless spectroscopic mode. First of all, for the galactic open cluster
NGC6611, in which, the number and the nature of emission line stars is still
the object of debates, we show that the number of true circumstellar emission
line stars is small. Second, at low metallicity, typically in the Small
Magellanic Cloud, B-type stars rotate faster than in the Milky Way and thus it
is expected a larger number of Be stars. However, till now, search for Be stars
was only performed in a very small number of open clusters in the Magellanic
Clouds. Using the ESO/WFI in its slitless spectroscopic mode, we performed a
Halpha survey of the Small Magellanic Cloud. 3 million low-resolution spectra
centered on Halpha were obtained in the whole SMC. Here, we present the method
to exploit the data and first results for 84 open clusters in the SMC about the
ratios of Be stars to B stars.


title: Investigating the flyby scenario for the HD 141569 system

abstract:
  HD 141569, a triple star system, has been intensively observed and studied
for its massive debris disk. It was rather regarded as a gravitationally bound
triple system but recent measurements of the HD 141569A radial velocity seem to
invalidate this hypothesis. The flyby scenario has therefore to be investigated
to test its compatibility with the observations. We present a study of the
flyby scenario for the HD141569 system, by considering 3 variants: a sole
flyby, a flyby associated with one planet and a flyby with two planets. We use
analytical calculations and perform N-body numerical simulations of the flyby
encounter. The binary orbit is found to be almost fixed by the observational
constraint on a edge-on plane with respect to the observers. If the binary has
had an influence on the disk structure, it should have a passing time at the
periapsis between 5000 and 8000 years ago and a distance at periapsis between
600 and 900 AU. The best scenario for reproducing the disk morphology is a
flyby with only 1 planet. For a 2 Mj (resp. 8 Mj) planet, its eccentricity must
be around 0.2 (resp. below 0.1). In the two cases, its apoapsis is about 130
AU. Although the global disk shape is reasonably well reproduced, some features
cannot be explain by the present model and the likehood of the flyby event
remains an issue. Dynamically speaking, HD 141569 is still a puzzling system.


title:
Testing Many-Worlds Quantum Theory By Measuring Pattern Convergence
  Rates

abstract:
  The Born Interpretation of the wave function gives only the relative
frequencies as the number of observations approaches infinity. Using the
Many-Worlds Interpretation of quantum mechanics, specifically the fact that
there must exist other versions of ourselves in the multiverse, I show that the
observed frequencies should approach the Born frequencies as 1/N, where N is
the number of observations. In the body of the paper I state this convergence
rate precisely as AN EASILY TESTABLE FORMULA. We can therefore test the central
claim of the MWI by measuring the convergence rate to the final Born frequency.
Conversely, the MWI allows us to calculate this convergence rate.


title: A Tannaka Theorem for Proper Lie Groupoids

abstract:
  By replacing the category of smooth vector bundles over a manifold with the
category of what we call smooth Euclidean fields, which is a proper enlargement
of the former, and by considering smooth actions of Lie groupoids on smooth
Euclidean fields, we are able to prove a Tannaka duality theorem for proper Lie
groupoids. The notion of smooth Euclidean field we introduce here is the
smooth, finite dimensional analogue of the usual notion of continuous Hilbert
field.


title: Flavor asymmetry of the nucleon

abstract:
  The flavor asymmetry of the nucleon sea is discussed in an unquenched quark
model for baryons in which the effects of quark-antiquark pairs (u anti-u, d
anti-d and s anti-s) are taken into account in an explicit form. The inclusion
of q anti-q pairs leads automatically to an excess of anti-d over anti-u quarks
in the proton, in agreement with experimental data.


title: Essential cohomology for elementary abelian p-groups

abstract:
  For an odd prime p the cohomology ring of an elementary abelian p-group is
polynomial tensor exterior. We show that the ideal of essential classes is the
Steenrod closure of the class generating the top exterior power. As a module
over the polynomial algebra, the essential ideal is free on the set of Mui
invariants.


title:
Ground-state properties of the two-site Hubbard-Holstein model: an exact
  solution

abstract:
  We revisit the two-site Hubbard-Holstein model by using extended phonon
coherent states. The nontrivial singlet bipolaron is studied exactly in the
whole coupling regime. The ground-state (GS) energy and the double occupancy
probability are calculated. The linear entropy is exploited successfully to
quantify bipartite entanglement between electrons and their environment
phonons, displaying a maximum entanglement of the singlet-bipolaron in strong
coupling regime. A dramatic drop in the crossover regime is observed in the GS
fidelity and its susceptibility. The bipolaron properties is also characterized
classically by correlation functions. It is found that the crossover from a
two-site to single-site bipolaron is more abrupt and shifts to a larger
electron-phonon coupling strength as electron-electron Coulomb repulsion
increases.


title:
Conformality of a differential with respect to Cheeger-Gromoll type
  metrics

abstract:
  We investigate conformality of the differential of a mapping between
Riemannian manifolds if the tangent bundles are equipped with a generalized
metric of Cheeger-Gromoll type.


title: Medium dependence of multiplicity distributions in MLLA

abstract:
  We study the modification of the multiplicity distributions in MLLA due to
the presence of a QCD medium. The medium is introduced though a multiplicative
constant ($f_{med}$) in the soft infrared parts of the kernels of QCD evolution
equations. Using the asymptotic ansatz for quark and gluons mean multiplicities
$<n_G>=e^{\gamma y}$ and $<n_Q>=r^{-1}e^{\gamma y}$ respectively, we study two
cases: fixed $\gamma$ as previously considered in the literature, and fixed
$\alpha_s$. We find opposite behaviors of the dispersion of the multiplicity
distributions with increasing $f_{med}$ in both cases. For fixed $\gamma$ the
dispersion decreases, while for fixed $\alpha_s$ it increases.


title:
Hyperinvariant subspace for weighted composition operator on
  $L^p([0,1]^d)$

abstract:
  The main result of this paper is the existence of a hyperinvariant subspace
of weighted composition operator $Tf=vf\circ\tau$ on $L^p([0,1]^d)$, ($1 \leq p
\leq \infty$) when the weight $v$ is in the class of ``generalized
polynomials'' and the composition map is a bijective ergodic transform
satisfying a given discrepancy. The work is based on the construction of a
functional calculus initiated by Wermer and generalized by Davie.


title: Non-Abelian bundles on heterotic non-compact K3 orbifold blowups

abstract:
  Instantons on Eguchi-Hanson spaces provide explicit examples of stable
bundles on non-compact four dimensional C^2/Z_n orbifold resolutions with
non-Abelian structure groups. With this at hand, we can consider
compactifications of ten dimensional SO(32) supergravity (arising as the low
energy limit of the heterotic string) on the resolved spaces in the presence of
non-Abelian bundles. We provide explicit examples in the resolved C^2/Z_3 case,
and give a complete classification of all possible effective six dimensional
models where the instantons are combined with Abelian gauge fluxes in order to
fulfil the local Bianchi identity constraint. We compare these models with the
corresponding C^2/Z_3 orbifold models, and find that all of these gauge
backgrounds can be related to configurations of vacuum expectation values
(VEV's) of twisted and sometimes untwisted states. Gauge groups and spectra are
identical from both the orbifold and the smooth bundle perspectives.


title: Spectrum of closed k-strings in D=2+1

abstract:
  We calculate the excitation spectrumof closed k-strings in 2+1 dimensional
SU(N) gauge theories for N = 4, 5 and k = 2. Our results demonstrate that the
low-lying spectrum of the k = 2 string falls into sectors that belong to nearly
pure antisymmetric and symmetric representations, showing that k-strings know
not only about the centre of the group, but also about the full group. We also
observe that the lightest states in each irreducible representation are
consistent with what one would expect from an effective string theory that
belongs to the same bosonic universality class (Nambu-Goto) as the fundamental
string. We find that the corrections compared to the free string theory are of
O(1), in striking contrast to the very small correction observed for the
fundamental string. We also observe unbound w = 2 states.


title: Long-time tails and cage effect in driven granular fluids

abstract:
  We study the velocity autocorrelation function (VACF) of a driven granular
fluid in the stationary state in 3 dimensions. As the critical volume fraction
of the glass transition in the corresponding elastic system is approached, we
observe pronounced cage effects in the VACF as well as a strong decrease of the
diffusion constant. At moderate densities the VACF is shown to decay
algebraically in time (t^{-3/2}) like in a molecular fluid, as long as the
driving conserves momentum locally.


title: Implementation of a medium-modified parton shower algorithm

abstract:
  We present a Monte Carlo implementation of medium-induced gluon radiation in
the final-state branching process. Medium effects are introduced through an
additive term in the splitting functions. We have implemented such modification
within PYTHIA. We show the medium effects on the hump-backed plateau, and the
transverse momentum and angular distributions with respect to the parent
parton. As expected, with increasing medium densities there is an increase
(decrease) of partons with small (large) momentum fraction, and angular
broadening is observed. The effects on the transverse-momentum distributions
are more involved, with an enhancement of low- and intermediate-$p_T$ partons
and a decrease at large $p_T$, which is related to energy conservation, and to
the lack of momentum exchange with the medium in our approach.


title:
Hydrodynamic Processes in Young Binary Systems as a Source of Cyclic
  Variations of Circumstellar Extinction

abstract:
  Hydrodynamic models of a young binary system accreting matter from the
remnants of a protostellar cloud have been calculated by the SPH method. It is
shown that periodic variations in column density in projection onto the primary
component take place at low inclinations of the binary plane to the line of
sight. They can result in periodic extinction variations. Three periodic
components can exist in general case. The first component has a period equal to
the orbital one and is attributable to the streams of matter penetrating into
the inner regions of the binary. The second component has a period that is a
factor of 5-8 longer than the orbital one and is related to the density waves
generated in a circumbinary (CB) disk. The third, longest period is
attributable to the precession of the inner asymmetric region of CB disk. The
relationship between the amplitudes of these cycles depends on the model
parameters as well as on the inclination and orientation of the binary in
space. We show that at a dust-to-gas ratio of 1:100 and and a mass extinction
coefficient of 250 cm$^2$ g$^{-1}$, the amplitude of the brightness variations
of the primary component in the V-band can reach $1^m$ at a mass accretion rate
onto the binary components of $10^{-8} M_{\odot}$ yr$^{-1}$ and a $10^{\rm o}$
inclination of the binary plane to the line of sight. We discuss possible
applications of the model to pre-main-sequence stars.


title:
Boundary slopes and the numbers of positive/negative crossings for
  Montesinos knots

abstract:
  We show that a finite numerical boundary slope of an essential surface in the
exterior of a Montesinos knot is bounded above and below in terms of the
numbers of positive/negative crossings of a specific minimal diagram of the
knot.


title: Multifractal analysis for conformal graph directed Markov systems

abstract:
  We derive the multifractal analysis of the conformal measure (or
equivalently, the invariant measure) associated to a family of weights imposed
upon a (multi-dimensional) graph directed Markov system (GDMS) using balls as
the filtration. This analysis is done over a large subset of the limit set. In
particular, it coincides with the limit set when the GDMS under scrutiny
satisfies a boundary separation condition. It also applies to more general
situations such as real or complex continued fractions.


title: Semi-direct Gauge Mediation

abstract:
  We describe a framework for gauge mediation of supersymmetry breaking in
which the messengers are charged under the hidden sector gauge group but do not
play a role in breaking supersymmetry. From this point of view, our framework
is between ordinary gauge mediation and direct mediation. As an example, we
consider the 3-2 model of dynamical supersymmetry breaking, and add to it
massive messengers which are SU(2) doublets. We briefly discuss the
phenomenology of this scenario.


title:
Early Universe cosmology in the light of the mirror dark matter
  interpretation of the DAMA/Libra signal

abstract:
  Mirror dark matter provides a simple framework for which to explain the
DAMA/Libra annual modulation signal consistently with the null results of the
other direct detection experiments. The simplest possibility involves ordinary
matter interacting with mirror dark matter via photon-mirror photon kinetic
mixing of strength epsilon ~ 10^(-9). We confirm that photon-mirror photon
mixing of this magnitude is consistent with constraints from ordinary Big Bang
nucleosynthesis as well as the more stringent constraints from cosmic microwave
background measurements and large scale structure considerations.


title: Notes on automorphisms of ultrapowers of II_1 factors

abstract:
  In functional analysis, approximative properties of an object become precise
in its ultrapower. We discuss this idea and its consequences for automorphisms
of II_1 factors. Here are some sample results: (1) an automorphism is
approximately inner if and only if its ultrapower is aleph_0-locally inner; (2)
the ultrapower of an outer automorphism is always outer; (3) for unital
*-homomorphisms from a separable nuclear C*-algebra into an ultrapower of a
II_1 factor, equality of the induced traces implies unitary equivalence. All
statements are proved using operator algebraic techniques, but in the last
section of the paper we indicate how the underlying principle is related to
theorems of Henson's positive bounded logic.


title: New Dimensions for Randall-Sundrum Phenomenology

abstract:
  We consider a 6D extension of the Randall-Sundrum (RS) model, RS6, where the
Standard Model (SM) gauge fields are allowed to propagate in an additional
dimension, compactified on $S^1$ or $S^1/Z_2$. In a minimal scenario, fermions
propagate in the 5D RS subspace and their localization provides a model of
flavor. New Kaluza-Klein (KK) states, corresponding to excitations of the gauge
fields along the 6th dimension, appear near the TeV scale. The new gauge KK
modes behave differently from those in the 5D warped models. These RS6 states
have couplings with strong dependence on 5D field localization and, within the
SM, only interact with heavy fermions and the Higgs sector, to a very good
approximation. Thus, the collider phenomenology of the new gauge KK states
sensitively depends on the 5D fermion geography. We briefly discuss inclusion
of SM fermions in all 6 dimensions, as well as the possibility of going beyond
6D.


title: Hilltop Quintessence

abstract:
  We examine hilltop quintessence models, in which the scalar field is rolling
near a local maximum in the potential, and w is close to -1. We first derive a
general equation for the evolution of the scalar field in the limit where w is
close to -1. We solve this equation for the case of hilltop quintessence to
derive w as a function of the scale factor; these solutions depend on the
curvature of the potential near its maximum. Our general result is in excellent
agreement (delta w < 0.5%) with all of the particular cases examined. It works
particularly well (delta w < 0.1%) for the pseudo-Nambu-Goldstone Boson
potential. Our expression for w(a) reduces to the previously-derived slow-roll
result of Sen and Scherrer in the limit where the curvature goes to zero.
Except for this limiting case, w(a) is poorly fit by linear evolution in a.


title: Integer Cech Cohomology of Icosahedral Projection Tilings

abstract:
  The integer Cech cohomology of canonical projection tilings of dimension
three and codimension three is derived. These formulae are then evaluated for
several icosahedral tilings known from the literature. Rather surprisingly, the
cohomologies of all these tilings turn out to have torsion. This is the case
even for the Danzer tiling, which is, in some sense, the simplest of all
icosahedral tilings. This result is in contrast to the case of two-dimensional
canonical projection tilings, where many examples without torsion are known.


title: Algebraic (2,2)-transformation groups

abstract:
  This paper contains the more significant part of the article with the same
title that will appear in the Volume 12 of Journal of Group Theory (2009).
  In this paper we determine all algebraic transformation groups $G$, defined
over an algebraically closed field $\sf k$, which operate transitively, but not
primitively, on a variety $\Omega$, provided the following conditions are
fulfilled. We ask that the (non-effective) action of $G$ on the variety of
blocks is sharply 2-transitive, as well as the action on a block $\Delta$ of
the normalizer $G_\Delta$. Also we require sharp transitivity on pairs $(X,Y)$
of independent points of $\Omega$, i.e. points contained in different blocks.


title: Two-component galaxies with flat rotation curve

abstract:
  Dynamical properties of two-component galaxy models whose stellar density
distribution is described by a gamma-model while the total density distribution
has a pure r^(-2) profile, are presented. The orbital structure of the stellar
component is described by Osipkov-Merritt anisotropy, while the dark matter
halo is isotropic. After a description of minimum halo models, the positivity
of the phase-space density (the model consistency) is investigated, and
necessary and sufficient conditions for consistency are obtained analytically
as a function of the stellar inner density slope gamma and anisotropy radius.
The explicit phase-space distribution function is recovered for integer values
of gamma, and it is shown that while models with gamma>4/17 are consistent when
the anisotropy radius is larger than a critical value (dependent on gamma), the
gamma=0 models are unphysical even in the fully isotropic case. The Jeans
equations for the stellar component are then solved analytically; in addition,
the projected velocity dispersion at the center and at large radii are also
obtained analytically for generic values of the anisotropy radius, and it is
found that they are given by remarkably simple expressions. The presented
models, even though highly idealized, can be useful as starting point for more
advanced modeling of the mass distribution of elliptical galaxies in studies
combining stellar dynamics and gravitational lensing.


title: Asymptotic Entanglement Dynamics and Geometry of Quantum States

abstract:
  A given dynamics for a composite quantum system can exhibit several distinct
properties for the asymptotic entanglement behavior, like entanglement sudden
death, asymptotic death of entanglement, sudden birth of entanglement, etc. A
classification of the possible situations was given in [M. O. Terra Cunha,
{\emph{New J. Phys}} {\bf{9}}, 237 (2007)] but for some classes there were no
known examples. In this work we give a better classification for the possibile
relaxing dynamics at the light of the geometry of their set of asymptotic
states and give explicit examples for all the classes. Although the
classification is completely general, in the search of examples it is
sufficient to use two qubits with dynamics given by differential equations in
Lindblad form (some of them non-autonomous). We also investigate, in each case,
the probabilities to find each possible behavior for random initial states.


title: Bounded Cohomology and $l_1$-Homology of Three-Manifolds

abstract:
  In this paper we define, for each aspherical orientable 3-manifold $M$
endowed with a \emph{torus splitting} $\c{T}$, a 2-dimensional fundamental
$l_1$-class $[M]^{\c{T}}$ whose $l_1$-norm has similar properties as the Gromov
simplicial volume of $M$ (additivity under torus splittings and isometry under
finite covering maps). Next, we use the Gromov simplicial volume of $M$ and the
$l_1$-norm of $[M]^{\c{T}}$ to give a complete characterization of those
nonzero degree maps $f\co M\to N$ which are homotopic to a ${\rm
deg}(f)$-covering map. As an application we characterize those degree one maps
$f\co M\to N$ which are homotopic to a homeomorphism in terms of bounded
cohomology classes.


title:
The Fitzpatrick function - a bridge between convex analysis and
  multivalued stochastic differential equations

abstract:
  Using the Fitzpatrick function, we characterize the solutions for different
classes of deterministic and stochastic differential equations driven by
maximal monotone operators (or in particular subdifferential operators) as the
minimum point of a suitably chosen convex lower semicontinuous function. Such
technique provides a new approach for the existence of the solutions for the
considered equations.


title: The arithmetic of trees

abstract:
  The arithmetic of the natural numbers can be extended to arithmetic
operations on planar binary trees. This gives rise to a non-commutative
arithmetic theory. In this exposition, we describe this arithmetree, first
defined by Loday, and investigate prime trees.


title: Pattern Rigidity in Hyperbolic Spaces: Duality and PD Subgroups

abstract:
  For $i= 1,2$, let $G_i$ be cocompact groups of isometries of hyperbolic space
$\Hyp^n$ of real dimension $n$, $n \geq 3$. Let $H_i \subset G_i$ be infinite
index quasiconvex subgroups satisfying one of the following conditions: 1)
limit set of $H_i$ is a codimension one topological sphere. 2) limit set of
$H_i$ is an even dimensional topological sphere. 3) $H_i$ is a codimension one
duality group. This generalizes (1). In particular, if $n = 3$, $H_i$ could be
any freely indecomposable subgroup of $G_i$. 4) $H_i$ is an odd-dimensional
Poincare Duality group $PD(2k+1)$. This generalizes (2). We prove pattern
rigidity for such pairs extending work of Schwartz who proved pattern rigidity
when $H_i$ is cyclic. All this generalizes to quasiconvex subgroups of uniform
lattices in rank one symmetric spaces satisfying one of the conditions (1)-(4),
as well as certain special subgroups with disconnected limit sets. In
particular, pattern rigidity holds for all quasiconvex subgroups of hyperbolic
3-manifolds that are not virtually free. Combining this with a result of
Mosher-Sageev-Whyte, we get quasi-isometric rigidity results for graphs of
groups where the vertex groups are uniform lattices in rank one symmetric
spaces and edge groups are of any of the above types.


title: Nonholonomic Lorentzian geometry on some $\mathbb H$-type groups

abstract:
  We consider examples of the $\mathbb H$-type groups with the natural
horizontal distribution generated by the commutation relations of the group. In
the contrast with the previous studies we furnish the horizontal distribution
with the Lorentzian metric, which is nondegenerate metric of index 1 instead of
a positive definite quadratic form. The causal character is defined. We study
the reachable set by timelike future directed curves. The parametric equations
of geodesics are obtained.


title:
Bias dependence of magnetic exchange interactions: application to
  interlayer exchange coupling in spin valves

abstract:
  We study how a bias voltage changes magnetic exchange interactions. We derive
a general expression for magnetic exchange interactions for systems coupled to
reservoirs under a bias potential, and apply it to spin valves. We find that
for metallic systems, the interlayer exchange coupling shows a weak,
oscillatory dependence on the bias potential. For tunneling systems, we find a
quadratic dependence on the bias potential, and derive an approximate
expression for this bias dependence for a toy model. We give general conditions
for when the interlayer exchange coupling is a quadratic function of bias
potential.


title: Velocity fluctuations of a piston confining a vibrated granular gas

abstract:
  The steady state velocity fluctuations of a movable piston located on the top
of a vibrated granular gas are studied by means of molecular dynamics
simulations. From the second moment of the distribution, a temperature
parameter for the piston is defined and compared with the granular temperature
of the gas located just below it. Then the two temperature parameters refer to
two interacting macroscopic systems. The equipartition of energy valid in usual
molecular systems is strongly violated, and the temperature of the piston can
be larger or smaller than the one of the gas, depending of the parameters
defining the system at the particle level. The simulation results for the ratio
of temperatures are in agreement with some theoretical predictions from kinetic
theory assuming the validity of a hydrodynamic description in the limit of weak
inelasticity of the gas.


title: Langlands duality for representations of quantum groups

abstract:
  We establish a correspondence (or duality) between the characters and the
crystal bases of finite-dimensional representations of quantum groups
associated to Langlands dual semi-simple Lie algebras. This duality may also be
stated purely in terms of semi-simple Lie algebras. To explain this duality, we
introduce an "interpolating quantum group" depending on two parameters which
interpolates between a quantum group and its Langlands dual. We construct
examples of its representations, depending on two parameters, which interpolate
between representations of two Langlands dual quantum groups.


title:
Spatial features of population dynamics arising from mutual interaction
  of different age groups in rodents

abstract:
  We study the dynamics of the transmission of the hanta virus infection among
mouse populations, taking into account, simultaneously, seasonal variations of
the environment and interactions within two classes in the mouse population:
adults and subadults. The interactions considered are not symmetric between the
two age-organized classes and are responsible for driving the younger members
away from home ranges. We consider the case of a bounded habitat affected by
seasonal variations.


title:
Momentum dependence of the superconducting gap in
  Ba$_{1-x}$K$_{x}$Fe$_2$As$_2$

abstract:
  The precise momentum dependence of the superconducting gap in the
iron-arsenide superconductor with Tc = 32K (BKFA) was determined from
angle-resolved photoemission spectroscopy (ARPES) via fitting the distribution
of the quasiparticle density to a model. The model incorporates finite lifetime
and experimental resolution effects, as well as accounts for peculiarities of
BKFA electronic structure. We have found that the value of the superconducting
gap is practically the same for the inner Gamma-barrel, X-pocket, and
"blade"-pocket, and equals 9 meV, while the gap on the outer Gamma-barrel is
estimated to be less than 4 meV, resulting in 2Delta/kT_c=6.8 for the large
gap, and 2Delta/kT_c<3 for the small gap. A large (77 \pm 3%)
non-superconducting component in the photoemission signal is observed below
T_c. Details of gap extraction from ARPES data are discussed in Appendix.


title: Feynman disentangling method and group theory

abstract:
  The subject of this work is to apply the modified Feynman disentangling
approach to a problem of transitions in a non-quadratic quantum-mechanical
system: a singular oscillator with a time-dependent frequency.