title:
Ferromagnetism in 2p Light Element-Doped II-oxide and III-nitride
  Semiconductors

abstract:
  II-oxide and III-nitride semiconductors doped by nonmagnetic 2p light
elements are investigated as potential dilute magnetic semiconductors (DMS).
Based on our first-principle calculations, nitrogen doped ZnO, carbon doped
ZnO, and carbon doped AlN are predicted to be ferromagnetic. The ferromagnetism
of such DMS materials can be attributed to a p-d exchange-like p-p coupling
interaction which is derived from the similar symmetry and wave function
between the impurity (p-like t_2) and valence (p) states. We also propose a
co-doping mechanism, using beryllium and nitrogen as dopants in ZnO, to enhance
the ferromagnetic coupling and to increase the solubility and activity.


title:
Semiclassical Resonances of Schr\"odinger operators as zeroes of
  regularized determinants

abstract:
  We prove that the resonances of long range perturbations of the
(semiclassical) Laplacian are the zeroes of natural perturbation determinants.
We more precisely obtain factorizations of these determinants of the form $
\prod_{w = {\rm resonances}}(z-w) \exp (\varphi_p(z,h)) $ and give
semiclassical bounds on $ \partial_z \varphi_p $ as well as a representation of
Koplienko's regularized spectral shift function. Here the index $ p \geq 1 $
depends on the decay rate at infinity of the perturbation.


title:
Absence of singular continuous diffraction for discrete multi-component
  particle models

abstract:
  Particle models with finitely many types of particles are considered, both on
$\mathbb{Z}^d$ and on discrete point sets of finite local complexity. Such sets
include many standard examples of aperiodic order such as model sets or certain
substitution systems. The particle gas is defined by an interaction potential
and a corresponding Gibbs measure. Under some reasonable conditions on the
underlying point set and the potential, we show that the corresponding
diffraction measure almost surely exists and consists of a pure point part and
an absolutely continuous part with continuous density. In particular, no
singular continuous part is present.


title: Topological correlations and asymptotic freedom in cellular aggregates

abstract:
  In random cellular systems, both observation and maximum entropy inference
give a specific form to the topological pair correlation: it is bi-affine in
the cells number of edges with coefficients depending on the distance between
the two cells of the pair. Assuming this form for the pair correlations, we
make explicit the conditions of statistical independence at large distance.
When, on average, the defects do not contribute, the layer population and the
enclosed topological charge both increase polynomially with distance. In
dimension 2, the exponent of the leading terms depend on sum rules satisfied,
or not, by the maximum entropy coefficients.


title:
On the 5D differential calculus and translation transformations in 4D
  kappa-Minkowski noncommutative spacetime

abstract:
  We perform a Noether analysis for a description of translation
transformations in 4D $\kappa$-Minkowski noncommutative spacetime which is
based on the structure of a 5D differential calculus. The techniques that some
of us had previously developed (hep-th/0607221) for a description of
translation transformations based on a 4D differential calculus turn out to be
applicable without any modification, and they allow us to show that the basis
usually adopted for the 5D calculus does not take into account certain aspects
of the structure of time translations in $\kappa$-Minkowski. We propose a
change of basis for the 5D calculus which leads to a more intuitive description
of time translations.


title:
Phenomenological theory of nonergodic phenomena in dipole- and
  spin-glasses

abstract:
  The path-dependent magnetizations (polarizations) and susceptibilities in
dipole- and spin-glasses are described analytically for the standard protocols
of temperature and field variations using the phenomenological Landau-type
description of multiple metastable states in the nonergodic phases. The
immediate manifestation of metastable states' multiplicity as staircases of
magnetizations (polarizations) curves in the temperature cycling experiments is
explained and described. The obtained results are in a reasonable qualitative
agreement with the existing experimental data.


title: Toward Psycho-robots

abstract:
  We try to perform geometrization of psychology by representing mental states,
<<ideas>>, by points of a metric space, <<mental space>>. Evolution of ideas is
described by dynamical systems in metric mental space. We apply the mental
space approach for modeling of flows of unconscious and conscious information
in the human brain. In a series of models, Models 1-4, we consider cognitive
systems with increasing complexity of psychological behavior determined by
structure of flows of ideas. Since our models are in fact models of the
AI-type, one immediately recognizes that they can be used for creation of
AI-systems, which we call psycho-robots, exhibiting important elements of human
psyche. Creation of such psycho-robots may be useful improvement of domestic
robots. At the moment domestic robots are merely simple working devices (e.g.
vacuum cleaners or lawn mowers) . However, in future one can expect demand in
systems which be able not only perform simple work tasks, but would have
elements of human self-developing psyche. Such AI-psyche could play an
important role both in relations between psycho-robots and their owners as well
as between psycho-robots. Since the presence of a huge numbers of
psycho-complexes is an essential characteristic of human psychology, it would
be interesting to model them in the AI-framework.


title: Graphene Nanoribbon and Graphene Nanodisk

abstract:
  We study electronic properties of graphene derivatives which have closed
edges. They are finite-length graphene nanoribbons and graphene nanodisks. No
metallic states are found in finite-length zigzag nanoribbons though all
infinite-length zigzag nanoribbons are metallic. We also study hexagonal,
parallelogrammic and trigonal nanodisks with zigzag or armchair edges. No
metallic states are found in these nanodisks either except trigonal zigzag
nanodisks. It is interesting that we can design the degeneracy of the metallic
states arbitrarily in trigonal zigzag nanodisks by changing the size.


title: On Kato's method for Navier--Stokes Equations

abstract:
  We investigate Kato's method for parabolic equations with a quadratic
non-linearity in an abstract form. We extract several properties known from
linear systems theory which turn out to be the essential ingredients for the
method. We give necessary and sufficient conditions for these conditions and
provide new and more general proofs, based on real interpolation. In
application to the Navier-Stokes equations, our approach unifies several
results known in the literature, partly with different proofs. Moreover, we
establish new existence and uniqueness results for rough initial data on
arbitrary domains in ${\mathbb R}^3$ and irregular domains in ${\mathbb R}^n$.


title:
Microphase morphology in two dimensional fluids under lateral
  confinement

abstract:
  We study the effects of confinement between two parallel walls on a two
dimensional fluid with competing interactions which lead to the formation of
particle micro-domains at the thermodynamic equilibrium (microphases or
microseparation). The possibility to induce structural changes of the
morphology of the micro-domains is explored, under different confinement
conditions and temperatures. In presence of neutral walls, a switch from
stripes of particles to circular clusters (droplets) occurs as the temperature
decreases, which does not happen in bulk. While the passage from droplets to
stripes, as the density increases, is a well known phenomenon, the change of
the stripes into droplets as an effect of temperature is rather unexpected.
Depending on the wall separation and on the wall-fluid interaction parameters,
the stripes can switch from parallel to perpendicular to the walls and also a
mixed morphology can be stable.


title:
B\"acklund Transformations for Noncommutative Anti-Self-Dual Yang-Mills
  Equations

abstract:
  We present Backlund transformations for the noncommutative anti-self-dual
Yang-Mills equation where the gauge group is G=GL(2) and use it to generate a
series of exact solutions from a simple seed solution. The solutions generated
by this approach are represented in terms of quasideterminants and belong to a
noncommutative version of the Atiyah-Ward ansatz. In commutative limit, our
results coincide with those by Corrigan, Fairlie, Yates and Goddard.


title:
Understanding the volatility smile of options markets through
  microsimulation

abstract:
  In this work, we aim to gain a better understanding of the volatility smile
observed in options markets through microsimulation (MS). We adopt two types of
active traders in our MS model: speculators and arbitrageurs, and call and put
options on one underlying asset. Speculators make decisions based on their
expectations of the asset price at the option expiration time. Arbitrageurs
trade at different arbitrage opportunities such as violation of put-call
parity. Difference in liquidity among options is also included. Notwithstanding
its simplicity, our model can generate implied volatility (IV) curves similar
to empirical observations. Our results suggest that the volatility smile is
related to the competing effect of heterogeneous trading behavior and the
impact of differential liquidity.


title:
Parameter Estimation in Biokinetic Degradation Models in Wastewater
  Treatment - A Novel Approach Relevant for Micro-pollutant Removal

abstract:
  In this paper we address a general parameter estimation methodology for an
extended biokinetic degradation model [1] for poorly degradable
micropollutants. In particular we concentrate on parameter estimation of the
micropollutant degradation sub-model by specialised microorganisms. In this
case we focus on the case when only substrate degradation data are available
and prove the structural identifiability of the model. Further we consider the
problem of practical identifiability and propose experimental and related
numerical methods for unambiguous parameter estimation based on multiple
substrate degradation curves with different initial concentrations. Finally by
means of simulated pseudo-experiments we have found convincing indications that
the proposed algorithm is stable and yields appropriate parameter estimates
even in unfavourable regimes.


title: AdS/CFT and Exclusive Processes in QCD

abstract:
  The AdS/CFT correspondence between string theory in AdS space and conformal
field theories in physical space-time leads to an analytic, semi-classical
model for strongly-coupled QCD which has scale invariance and dimensional
counting at short distances and color confinement at large distances. One can
use holography to map the amplitude describing the hadronic state in the fifth
dimension of Anti-de Sitter space to the light-front wavefunctions of hadrons
in physical space-time, thus providing a relativistic description of hadrons in
QCD at the amplitude level. In particular, we show that there is an exact
correspondence between the fifth-dimensional coordinate of AdS space z and a
specific impact variable zeta which measures the separation of the quark and
gluonic constituents within the hadron in ordinary space-time. New relativistic
light-front equations in ordinary space-time can then be derived which
reproduce the results obtained using the 5-dimensional theory. The effective
light-front equations possess elegant algebraic structures and integrability
properties. This connection between the AdS and the light-front representations
allows one to compute the analytic form of the frame-independent light-front
wavefunctions, the fundamental entities which encode hadron properties and
allow the computation of decay constants, form factors, deeply virtual Compton
scattering, exclusive heavy hadron decays and other exclusive scattering
amplitudes. As specific examples we compute the pion coupling constant and
study the behavior of the pion form factor in the space and time-like regions.
We also determine the Dirac form factors of the proton and neutron in the
space-like region.


title: Strong asymptotics for Christoffel functions of planar measures

abstract:
  We prove a version of strong asymptotics of Christoffel functions with
varying weights for a general class of sets E and measures in the complex
plane. This class includes all regular measures in the sense of Stahl-Totik on
regular compact sets E in the plane and even allows varying weights. Our main
theorems cover some known results for subsets E of the real line R; in
particular, we recover information in the case of E=R with Lebesgue measure dx
and weight w(x) = exp(-Q(x)) where Q(x) is a nonnegative, even degree
polynomial having positive leading coefficient.


title: Generalized entropies and open random and scale-free networks

abstract:
  We propose the concept of open network as an arbitrary selection of nodes of
a large unknown network. Using the hypothesis that information of the whole
network structure can be extrapolated from an arbitrary set of its nodes, we
use Renyi mutual entropies in different q-orders to establish the minimum
critical size of a random set of nodes that represents reliably the information
of the main network structure. We also identify the clusters of nodes
responsible for the structure of their containing network.


title: Detecting Chameleons through Casimir Force Measurements

abstract:
  The best laboratory constraints on strongly coupled chameleon fields come not
from tests of gravity per se but from precision measurements of the Casimir
force. The chameleonic force between two nearby bodies is more akin to a
Casimir-like force than a gravitational one: The chameleon force behaves as an
inverse power of the distance of separation between the surfaces of two bodies,
just as the Casimir force does. Additionally, experimental tests of gravity
often employ a thin metallic sheet to shield electrostatic forces, however this
sheet mask any detectable signal due to the presence of a strongly coupled
chameleon field. As a result of this shielding, experiments that are designed
to specifically test the behaviour of gravity are often unable to place any
constraint on chameleon fields with a strong coupling to matter. Casimir force
measurements do not employ a physical electrostatic shield and as such are able
to put tighter constraints on the properties of chameleons fields with a strong
matter coupling than tests of gravity. Motivated by this, we perform a full
investigation on the possibility of testing chameleon model with both present
and future Casimir experiments. We find that present days measurements are not
able to detect the chameleon. However, future experiments have a strong
possibility of detecting or rule out a whole class of chameleon models.


title:
The Stellar Content of Galaxy Halos: A Comparison between LambdaCDM
  Models and Observations of M31

abstract:
  Recent observations have revealed that high surface-brightness, metal-rich
debris is present over large regions of the Andromeda (M31) stellar halo. We
use a set of numerical models to determine whether extended metal-rich debris
is expected to exist in galaxy halos formed in a hierarchical LambdaCDM
universe. We identify tidal debris in the simulations according to the current
best surface brightness detection limits in M31 and demonstrate that bright
features in the outer halo regions usually originate from single satellites,
with very little contamination from other sources due to the low probability of
tidal streams from two overlapping accretion events. In contrast, high-surface
brightness features in the inner halo often originate from multiple
progenitors. We also compare the age and metallicity distribution of the debris
with the well-mixed stellar halos in which they reside. We find that
high-surface brightness tidal debris is produced almost exclusively by
relatively high mass progenitors (Mstar ~ 10^7- 10^9 Msun) and thus is expected
to be of moderate- to high-metallicity. Similarly, in our models the smooth
inner halo is expected to be metal-rich as this region has been built up mainly
from massive satellites. Our results imply that the stellar populations of
substructure observed around external galaxies with current techniques should
not resemble old and metal-poor dwarf spheroidal satellites, nor the underlying
component of the stellar halo.


title:
The XMM large scale structure survey: optical vs. X-ray classifications
  of active galactic nuclei and the unified scheme

abstract:
  Our goal is to characterize AGN populations by comparing their X-ray and
optical classifications. We present a sample of 99 spectroscopically identified
X-ray point sources in the XMM-LSS survey which are significantly detected in
the [2-10] keV band, and with more than 80 counts. We performed an X-ray
spectral analysis for all of these 99 X-ray sources. Introducing the fourfold
point correlation coefficient, we find only a mild correlation between the
X-ray and the optical classifications, as up to 30% of the sources have
differing X-ray and optical classifications: on one hand, 10% of the type 1
sources present broad emission lines in their optical spectra and strong
absorption in the X-rays. These objects are highly luminous AGN lying at high
redshift and thus dilution effects are totally ruled out, their discrepant
nature being an intrinsic property. Their X-ray luminosities and redshifts
distributions are consistent with those of the unabsorbed X-ray sources with
broad emission lines. On the other hand, 25/32 are moderate luminosity AGN,
which are both unabsorbed in the X-rays and only present narrow emission lines
in their optical spectra. The majority of them have an optical spectrum which
is representative of the host galaxy. We finally infer that dilution of the AGN
by the host galaxy seems to account for their nature. 5/25 have been defined as
Seyfert 2. In conclusion, most of these 32 discrepant cases can be accounted
for by the standard AGN unified scheme, as its predictions are not met for only
12% of the 99 X-ray sources. ABRIDGED


title:
Positrons from dark matter annihilation in the galactic halo:
  uncertainties

abstract:
  Indirect detection signals from dark matter annihilation are studied in the
positron channel. We discuss in detail the positron propagation inside the
galactic medium: we present novel solutions of the diffusion and propagation
equations and we focus on the determination of the astrophysical uncertainties
which affect the positron dark matter signal. We show that, especially in the
low energy tail of the positron spectra at Earth, the uncertainty is sizeable
and we quantify the effect. Comparison of our predictions with current
available and foreseen experimental data are derived.


title: FADE, an instrument to measure the atmospheric coherence time

abstract:
  After proposing a new method of deriving the atmospheric time constant from
the speed of focus variations (Kellerer & Tokovinin 2007), we now implement it
with the new instrument, FADE. FADE uses a 36-cm Celestron telescope that is
modified to transform stellar point images into a ring by increasing the
central obstruction and combining defocus with spherical aberration. Sequences
of images recorded with a fast CCD detector are processed to determine the
defocus and its variations in time from the ring radii. The temporal structure
function of the defocus is fitted with a model to derive the atmospheric seeing
and time constant. We investigated by numerical simulation the data reduction
algorithm and instrumental biases. Bias caused by instrumental effects, such as
optical aberrations, detector noise, acquisition frequency, etc., is
quantified. The ring image must be well-focused, i.e. must have a sufficiently
sharp radial profile, otherwise, scintillation seriously affects the results.
An acquisition frequency of 700 Hz appears adequate. FADE was operated for 5
nights at the Cerro Tololo observatory in parallel with the regular site
monitor. Reasonable agreement between the results from the two instruments has
been obtained.


title: Well-Posedness and Symmetries of Strongly Coupled Network Equations

abstract:
  We consider a diffusion process on the edges of a finite network and allow
for feedback effects between different, possibly non-adjacent edges. This
generalizes the setting that is common in the literature, where the only
considered interactions take place at the boundary, i. e., in the nodes of the
network. We discuss well-posedness of the associated initial value problem as
well as contractivity and positivity properties of its solutions. Finally, we
discuss qualitative properties that can be formulated in terms of invariance of
linear subspaces of the state space, i. e., of symmetries of the associated
physical system. Applications to a neurobiological model as well as to a system
of linear Schroedinger equations on a quantum graph are discussed.


title: Combined MASS-DIMM instrument for atmospheric turbulence studies

abstract:
  Several site-testing programs and observatories currently use combined
MASS-DIMM instruments for monitoring parameters of optical turbulence. The
instrument is described here. After a short recall of the measured quantities
and operational principles, the optics and electronics of MASS-DIMM,
interfacing to telescopes and detectors, and operation are covered in some
detail. Particular attention is given to the correct measurement and control of
instrumental parameters to ensure valid and well-calibrated data, to the data
quality and filtering. Examples of MASS-DIMM data are given, followed by the
list of present and future applications.


title:
Localized non-diffusive asymptotic patterns for nonlinear parabolic
  equations with gradient absorption

abstract:
  We study the large-time behaviour of the solutions $u$ of the evolution
equation involving nonlinear diffusion and gradient absorption $\partial_t u -
\Delta_p u + |\nabla u|^q=0$. We consider the problem posed for $x\in {\mathbb
R}^N $ and $t>0$ with non-negative and compactly supported initial data. We
take the exponent $p>2$ which corresponds to slow $p$-Laplacian diffusion, and
the exponent $q$ in the superlinear range $1<q<p-1$. In this range the
influence of the Hamilton-Jacobi term $ |\nabla u|^q$ is determinant, and gives
rise to the phenomenon of localization. The large time behaviour is described
in terms of a suitable self-similar solution that solves a Hamilton-Jacobi
equation. The shape of the corresponding spatial pattern is rather conical
instead of bell-shaped or parabolic.


title:
Economic dynamics with financial fragility and mean-field interaction: a
  model

abstract:
  Following the statistical mechanics methodology, firstly introduced in
macroeconomics by Aoki [1996,2002], we provide some insights to the well known
works of Greenwald and Stiglitz [1990, 1993]. Specifically, we reach
analytically a closed form solution of their models overcoming the aggregation
problem. The key idea is to represent the economy as an evolving complex
system, composed by heterogeneous interacting agents, that can partitioned into
a space of macroscopic states. This meso level of aggregation permits to adopt
mean field interaction modeling and master equation techniques.


title: On the Riemannian geometry of Seiberg-Witten moduli spaces

abstract:
  We construct natural Riemannian metrics on Seiberg-Witten moduli spaces and
study their geometry.


title:
MINT: a Computer Program for Adaptive Monte Carlo Integration and
  Generation of Unweighted Distributions

abstract:
  In this note I illustrate the program MINT, a FORTRAN program for Monte Carlo
adaptive integration and generation of unweighted distributions.


title: Analytic Structure of Three-Mass Triangle Coefficients

abstract:
  ``Three-mass triangles'' are a class of integral functions appearing in
one-loop gauge theory amplitudes. We discuss how the complex analytic
properties and singularity structures of these amplitudes can be combined with
generalised unitarity techniques to produce compact expressions for three-mass
triangle coefficients. We present formulae for the N=1 contributions to the
n-point NMHV amplitude.


title: The $K$-theory of toric varieties

abstract:
  Recent advances in computational techniques for $K$-theory allow us to
describe the $K$-theory of toric varieties in terms of the $K$-theory of fields
and simple cohomological data.


title: Adding \pm 1 to the argument of an Hall-Littlewood polynomial

abstract:
  Shifting by \pm 1 powers sums: p_i \to p_i \pm 1 induces a transformation on
symmetric functions that we detail in the case of Hall-Littlewood polynomials.
By iteration, this gives a description of these polynomials in terms of plane
partitions, as well as some generating functions. We recover in particular an
identity of Warnaar related to Rogers-Ramanujan identities.


title: Current noise through a Kondo quantum dot in a SU(N) Fermi liquid state

abstract:
  The current noise through a mesoscopic quantum dot is calculated and analyzed
in the Fermi liquid regime of the SU(N) Kondo model. Results connect the
Johnson-Nyquist noise to the shot noise for an arbitrary ratio of voltage and
temperature, and show that temperature corrections are sizeable in usual
experiments. For the experimentally relevant SU(4) case, quasiparticle
interactions are shown to increase the shot noise.


title:
On the Complexity of Computing Zero-Error and Holevo Capacity of Quantum
  Channels

abstract:
  One of the main problems in quantum complexity theory is that our
understanding of the theory of QMA-completeness is not as rich as its classical
analogue, the NP- completeness. In this paper we consider the clique problem in
graphs, which is NP- complete, and try to find its quantum analogue. We show
that, quantum clique problem can be defined as follows; Given a quantum
channel, decide whether there are k states that are distinguishable, with no
error, after passing through channel. This definition comes from reconsidering
the clique problem in terms of the zero-error capacity of graphs, and then
redefining it in quantum information theory. We prove that, quantum clique
problem is QMA-complete. In the second part of paper, we consider the same
problem for the Holevo capacity. We prove that computing the Holevo capacity as
well as the minimum entropy of a quantum channel is NP-complete. Also, we show
these results hold even if the set of quantum channels is restricted to
entanglement breaking ones.


title: Production of Gravitational Waves in the nMSSM

abstract:
  During a strongly first-order phase transition gravitational waves are
produced by bubble collisions and turbulent plasma motion. We analyze the
relevant characteristics of the electroweak phase transition in the nMSSM to
determine the generated gravitational wave signal. Additionally, we comment on
correlations between the production of gravitational waves and baryogenesis. We
conclude that the gravitational wave relic density in this model is generically
too small to be detected in the near future by the LISA experiment. We also
consider the case of a "Standard Model" with dimension-six Higgs potential,
which leads to a slightly stronger signal of gravitational waves.


title:
Matching NLO QCD computations with Parton Shower simulations: the POWHEG
  method

abstract:
  The aim of this work is to describe in detail the POWHEG method, first
suggested by one of the authors, for interfacing parton-shower generators with
NLO QCD computations. We describe the method in its full generality, and then
specify its features in two subtraction frameworks for NLO calculations: the
Catani-Seymour and the Frixione-Kunszt-Signer approach. Two examples are
discussed in detail in both approaches: the production of hadrons in e+e-
collisions, and the Drell-Yan vector-boson production in hadronic collisions.


title:
High-sensitivity tool for studying phonon related mechanical losses in
  low loss materials

abstract:
  Fundamental mechanical loss mechanisms exist even in very pure materials, for
instance, due to the interactions of excited acoustic waves with thermal
phonons. A reduction of these losses in a certain frequency range is desired in
high precision instruments like gravitational wave detectors. Systematic
analyses of the mechanical losses in those low loss materials are essential for
this aim, performed in a highly sensitive experimental set-up. Our novel method
of mechanical spectroscopy, cryogenic resonant acoustic spectroscopy of bulk
materials (CRA spectroscopy), is well suited to systematically determine losses
at the resonant frequencies of the samples of less than 10^(-9) in the wide
temperature range from 5 to 300 K. A high precision set-up in a specially built
cryostat allows contactless excitation and readout of the oscillations of the
sample. The experimental set-up and measuring procedure are described.
Limitations to our experiment due to external loss mechanisms are analysed. The
influence of the suspension system as well as the sample preparation is
explained.


title:
Quantum Spin Dynamics of Mode-Squeezed Luttinger Liquids in
  Two-Component Atomic Gases

abstract:
  We report on the observation of the phase dynamics of interacting
one-dimensional ultracold bosonic gases with two internal degrees of freedom.
By controlling the non-linear atomic interactions close to a Feshbach resonance
we are able to induce a phase diffusive many-body spin dynamics. We monitor
this dynamical evolution by Ramsey interferometry, supplemented by a novel,
many-body echo technique. We find that the time evolution of the system is well
described by a Luttinger liquid initially prepared in a multimode squeezed
state. Our approach allows us to probe the non-equilibrium evolution of
one-dimensional many-body quantum systems.


title: Probing quantum vacuum geometrical effects with cold atoms

abstract:
  The lateral Casimir-Polder force between an atom and a corrugated surface
should allow one to study experimentally non trivial geometrical effects in
quantum vacuum. Here, we derive the theoretical expression of this force in a
scattering approach that accounts for the optical properties of the corrugated
surface. We show that large corrections to the ``proximity force
approximation'' could be measured using present-day technology with a
Bose-Einstein condensate used as a vacuum field sensor.


title:
The HI content of Early-Type Galaxies from the ALFALFA survey I.
  Catalogued HI sources in the Virgo cluster

abstract:
  Aims: We are using the Arecibo Legacy Fast ALFA survey (ALFALFA), which is
covering 17% of the sky at 21 cm, to study the HI content of Early-Type
galaxies (ETG) in an unbiased way. The aim is to get an overall picture of the
hot, warm and cold ISM of ETG, as a function of galaxy mass and environment, to
understand its origin and fate, and to relate it to the formation and evolution
history of these objects. Methods: This paper deals with the first part of our
study, which is devoted to the 8-16 deg. declination strip in the Virgo
cluster. In this sky region, using the Virgo Cluster Catalogue (VCC), we have
defined an optical sample of 939 ETG, 457 of which are brighter than the VCC
completeness limit at B_T=18.0. We have correlated this optical sample with the
catalogue of detected HI sources from ALFALFA. Results: Out of the 389 ETG from
the VCC with B_T<=18.0, outside the 1 deg. region of poor HI detection around
M87, and corrected for background contamination of VCC galaxies without a known
radial velocity, only 9 galaxies (2.3%) are detected in HI with a completeness
limit of 3.5 and 7.6 x 10^7 Mo of HI for dwarf and giant ETG, respectively. In
addition 4 VCC ETG with fainter magnitudes are also detected. Our HI detection
rate is lower than previously claimed. The majority of the detected ETG appear
to have peculiar morphology and to be located near the edges of the Virgo
cluster. Conclusions: Our preliminary conclusion is that cluster ETG contain
very little neutral gas, with the exceptions of a few peculiar dwarf galaxies
at the edge of the ETG classification and of very few larger ETG, where the
cold gas could have a recent external origin.


title: Intersection Numbers of Polygon Spaces

abstract:
  We study the intersection ring of the space $\M(\alpha_1,...,\alpha_m)$ of
polygons in $\R^3$. We find homology cycles dual to generators of this ring and
prove a recursion relation in $m$ (the number of steps) for their intersection
numbers. This result is analog of the recursion relation appearing in the work
of Witten and Kontsevich on moduli spaces of punctured curves and on the work
of Weitsman on moduli spaces of flat connections on two-manifolds of genus $g$
with $m$ marked points. Based on this recursion formula we obtain an explicit
expression for the computation of the intersection numbers of polygon spaces
and use it in several examples. Among others, we study the special case of
equilateral polygon spaces (where all the $\alpha_i$ are the same) and compare
our results with the expressions for these particular spaces that have been
determined by Kamiyama and Tezuka. Finally, we relate our explicit formula for
the intersection numbers with the generating function for intersection pairings
of the moduli space of flat connections of Yoshida, as well as with equivalent
expressions for polygon spaces obtained by Takakura and Konno through different
techniques.


title: Antideuterons from supersymmetric dark matter

abstract:
  We calculate the antideuteron flux expected from dark matter annihilation in
the galactic halo. The propagation is treated in a full 2-D propagation model
consistent with the results obtained from the propagation of B/C and other
galactic species. We discuss the potentials of this indirect dark matter
detection means, with special emphasis on the possible sources of uncertainties
affecting future measurements


title: Representing simple d-dimensional polytopes by d polynomials

abstract:
  A polynomial representation of a convex d-polytope P is a finite set
\{p_1(x),...,p_n(x)\} of polynomials over E^d such that P=\setcond{x \in
\E^d}{p_1(x) \ge 0 {for every} 1 \le i \le n}. By s(d,P) we denote the least
possible number of polynomials in a polynomial representation of P. It is known
that d \le s(d,P) \le 2d-1. Moreover, it is conjectured that s(d,P)=d for all
convex d-polytopes P. We confirm this conjecture for simple d-polytopes by
providing an explicit construction of d polynomials that represent a given
simple d-polytope P.


title:
Real Time Evolution in Quantum Many-Body Systems With Unitary
  Perturbation Theory

abstract:
  We develop a new analytical method for solving real time evolution problems
of quantum many-body systems. Our approach is a direct generalization of the
well-known canonical perturbation theory for classical systems. Similar to
canonical perturbation theory, secular terms are avoided in a systematic
expansion and one obtains stable long-time behavior. These general ideas are
illustrated by applying them to the spin-boson model and studying its
non-equilibrium spin dynamics.


title: Observation of the Purcell effect in high-index-contrast micropillar

abstract:
  We have fabricated pillar microcavity samples with Bragg mirrors consisting
of alternate layers of GaAs and Aluminium Oxide. Compared to the more widely
studied GaAs/AlAs micropillars these mirrors can achieve higher reflectivities
with fewer layer repeats and reduce the mode volume. We have studied a number
of samples containing a low density of InGaAs/GaAs self assembled quantum dots
in a cavity and here report observation of a three fold enhancement in the
radiative lifetime of a quantum dot exciton state due to the Purcell effect.


title: Pluripolar hulls and fine analytic structure

abstract:
  We discuss the relation between pluripolar hulls and fine analytic structure.
Our main result is the following. For each non polar subset $S$ of the complex
plane $\mathbb C$ we prove that there exists a pluripolar set $E \subset (S
\times \mathbb C)$ with the property that the pluripolar hull of $E$ relative
to $\mathbb C^2$ contains no fine analytic structure and its projection onto
the first coordinate plane equals $\mathbb C$.


title:
Dipole-dipole interaction between orthogonal dipole moments in
  time-dependent geometries

abstract:
  In two nearby atoms, the dipole-dipole interaction can couple transitions
with orthogonal dipole moments. This orthogonal coupling accounts for a number
of interesting effects, but strongly depends on the geometry of the setup.
Here, we discuss several setups of interest where the geometry is not fixed,
such as particles in a trap or gases, by averaging over different sets of
geometries. Two averaging methods are compared. In the first method, it is
assumed that the internal electronic evolution is much faster than the change
of geometry, whereas in the second, it is vice versa. We find that the
orthogonal coupling typically survives even extensive averaging over different
geometries, albeit with qualitatively different results for the two averaging
methods. Typically, one- and two-dimensional averaging ranges modelling, e.g.,
low-dimensional gases, turn out to be the most promising model systems.


title: Homogeneous bundles and the first eigenvalue of symmetric spaces

abstract:
  We prove the stability of the Gieseker point of an irreducible homogeneous
bundle over a rational homogeneous space. As an application we get a sharp
upper estimate for the first eigenvalue of the Laplacian of an arbitrary
Kaehler metric on a compact Hermitian symmetric spaces of ABCD--type.


title: Oxide-apertured microcavity single-photon emitting diode

abstract:
  We have developed a microcavity single-photon source based on a single
quantum dot within a planar cavity in which wet-oxidation of a high-aluminium
content layer provides lateral confinement of both the photonic mode and the
injection current. Lateral confinement of the optical mode in optically pumped
structures produces a strong enhancement of the radiative decay rate. Using
microcavity structures with doped contact layers, we demonstrate a
single-photon emitting diode where current may be injected into a single dot.


title:
Measuring stellar magnetic fields with the low resolution
  spectropolarimeter of the William Herschel Telescope

abstract:
  Despite the influence of magnetic fields on the structure and evolution of
stars is largely demonstrated from the theoretical point of view, their
observational evidence in non-degenerated stars is still rather scanty and
mainly circumscribed to bright objects (V<10). Stellar magnetic fields are
commonly measured on the basis of circular spectropolarimetry at high/middle
resolution across the profile of metal lines. The present sensitivity of
telescopes and spectrographs makes this still an almost prohibitive method for
faint stars. In principle, stellar magnetic fields can be also measured on the
basis of low resolution spectropolarimetry, with very important results
obtained at the 8 m ESO telescopes with FORS1. The trade off between S/N and
spectral resolution in measuring stellar magnetic fields justify an attempt,
here presented, to perform these measurements at the 4.5 m William Herschel
Telescope. HD3360, one of the stars with the weakest known magnetic field, and
the magnetic chemically peculiar stars HD10783, HD74521 and HD201601 have been
observed with the spectropolarimeter ISIS in the 3785-4480 A range. Measured
stellar magnetic fields, from Stokes I and V spectra with S/N > 600, show an
internal error of <50 G selecting the whole interval and <200 G within a Balmer
line. Ripples in the Stokes V spectra of HD3360 result in an instrumental
positive magnetic field certainly not larger than 80 G.


title: The Mean Curvature of the Second Fundamental Form of a hypersurface

abstract:
  An expression for the first variation of the area functional of the second
fundamental form is given for a hypersurface in a semi-Riemannian space. The
concept of the "mean curvature of the second fundamental form" is then
introduced. Some characterisations of extrinsic hyperspheres in terms of this
curvature are given.


title: Robustness of community structure in networks

abstract:
  The discovery of community structure is a common challenge in the analysis of
network data. Many methods have been proposed for finding community structure,
but few have been proposed for determining whether the structure found is
statistically significant or whether, conversely, it could have arisen purely
as a result of chance. In this paper we show that the significance of community
structure can be effectively quantified by measuring its robustness to small
perturbations in network structure. We propose a suitable method for perturbing
networks and a measure of the resulting change in community structure and use
them to assess the significance of community structure in a variety of
networks, both real and computer generated.


title: Non-Topological Gauss-Bonnet type model of gravity with torsion

abstract:
  A non-topological Lorentz gauge model of gravity with torsion based on
Gauss-Bonnet type Lagrangian is considered. The Lagrangian differs from the
Lovelock term in four-dimensional space-time and has a number of interesting
features. We demonstrate that the model admits a propagating torsion unlike the
case of the topological Lovelock gravity. Due to additional symmetries of the
proposed Gauss-Bonnet type Lagrangian the torsion has a reduced set of
dynamical degrees of freedom corresponding to the spin two field, U(1) gauge
vector field and spin zero field. A remarkable feature is that the kinetic part
of the Hamiltonian containing the spin two field is positively defined. We
perform one-loop quantization of the model for a special case of constant
Riemann curvature space-time background treating the torsion as a quantum field
variable. We discuss a possible mechanism of emergent Einstein gravity as an
effective theory which can be induced due to quantum dynamics of torsion.


title:
The climate version of the Eta regional forecast model. 1. Evaluation of
  consistency between the Eta model and HadAM3P global model

abstract:
  The regional climate model prepared from Eta WS forecast model has been
integrated over South America with the horizontal resolution of 40 km for the
period of 1960-1990. The model was forced at its lateral boundaries by the
outputs of HadAM3P. The data of HadAM3P represent simulation of modern climate
with the resolution about 150 km. In order to prepare climate regional model
from the Eta forecast model multiple modifications and corrections were made in
the original model. The run of climate Eta model was made on the supercomputer
SX-6. The detailed analysis of the results of dynamical downscaling experiment
includes an investigation of a consistency between the regional and AGCM models
as well as of ability of the regional model to resolve important features of
climate fields on the finer scale than that resolved by AGCM. In this work the
results of the investigation of a consistency between the output fields of the
Eta model and HadAM3P are presented. The geopotential, temperature and wind
fields of both models were analysed. For the evaluation of the likeness of
these two models outputs,there were used Fourier analysis of time series,
consistency index, constituted from linear regression coefficients, time mean
and space mean models' arithmetic difference and root mean square difference,
dispersion analysis,and some others characteristics. This investigation
demonstrates that there are not significant differences in behaviour and
spatial arragement of large-scale structures of the two models. Also, the
regional model characteristics do not have considerable positive or negative
trend during integration time in relation to the global model characteristics.
  From the total analysis we can affirm that in the description of large-scale
climate structures these two models are in consistency.


title:
The Search for Extra Neutral Currents at the LHC: QCD and Anomalous
  Gauge Interactions

abstract:
  Extensions of the Standard Model with extra neutral currents due to
additional anomalous abelian gauge factors are considered. We summarize the
main features of the effective action associated to these theories. They are
characterized by an axion-like particle (the {\em axi-higgs}) which can be
(almost) massless, with its mass generated non-perturbatively in the QCD vacuum
as for an ordinary Peccei-Quinn axion, but that can also mix with the scalars
of the Higgs sector, becoming a heavy axion. We briefly describe the interplay
between the electroweak and the QCD sectors in these types of theories, which
emerge either from special vacua of string/brane theory; from partial
decoupling of a heavier fermion sector or from an anomaly inflow in the context
of models with extra dimensions.


title: D-term inflation after spontaneous symmetry breaking

abstract:
  We show that 1-loop quantum corrections to the potential energy density in
supersymmetric hybrid inflation, outside the inflationary valley, can not be
neglected. A method is presented to calculate these 1-loop corrections and they
are applied to the case of D-term hybrid inflation, where a significant amount
of inflation is shown to occur after spontaneous symmetry breaking. Taking this
into account improves the agreement with WMAP measurements. A gauge coupling of
up to 0.3 is still consistent with the CMB density perturbation. The spectral
index is predicted in between 0.98 and 1.00 and the cosmic string contribution
to the CMB anisotropy is sufficiently reduced.


title: Combination of quasiconvex subgroups of relatively hyperbolic groups

abstract:
  For relatively hyperbolic groups, we investigate conditions guaranteeing that
the subgroup generated by two quasiconvex subgroups $Q$ and $R$ is quasiconvex
and isomorphic to $Q \ast_{Q\cap R} R$. Our results generalized known
combination theorems for quasiconvex subgroups of word-hyperbolic groups. Some
applications are presented.


title: Bell's theorem as a signature of nonlocality: a classical counterexample

abstract:
  For a system composed of two particles Bell's theorem asserts that averages
of physical quantities determined from local variables must conform to a family
of inequalities. In this work we show that a classical model containing a local
probabilistic interaction in the measurement process can lead to a violation of
the Bell inequalities. We first introduce two-particle phase-space
distributions in classical mechanics constructed to be the analogs of quantum
mechanical angular momentum eigenstates. These distributions are then employed
in four schemes characterized by different types of detectors measuring the
angular momenta. When the model includes an interaction between the detector
and the measured particle leading to ensemble dependencies, the relevant Bell
inequalities are violated if total angular momentum is required to be
conserved. The violation is explained by identifying assumptions made in the
derivation of Bell's theorem that are not fulfilled by the model. These
assumptions will be argued to be too restrictive to see in the violation of the
Bell inequalities a faithful signature of nonlocality.


title:
NNLO Logarithmic Expansions and High Precision Determinations of the QCD
  background at the LHC: The case of the Z resonance

abstract:
  New methods of solutions of the DGLAP equation and their implementation
through NNLO in QCD are briefly reviewed. We organize the perturbative
expansion that describes in $x$-space the evolved parton distributions in terms
of scale invariant functions, which are determined recursively, and logarithms
of the ratio of the running couplings at the initial and final evolution
scales. Resummed solutions are constructed within the same approach and involve
logarithms of more complex functions, which are given in the non-singlet case.
Differences in the evolution schemes are shown to be numerically sizeable and
intrinsic to perturbation theory. We illustrate these points in the case of
Drell-Yan lepton pair production near the Z resonance, analysis that can be
extended to searches of extra $Z^{\prime}$. We show that the reduction of the
NNLO cross section compared to the NLO prediction may be attributed to the NNLO
evolution.


title:
Constructing non-equilibrium statistical ensemble formalism based on
  Subdynamics

abstract:
  In this work, we present a general non-equilibrium ensemble formalism based
on the subdynamic equation (SKE). The constructing procedure is to use a
similarity transformation between Gibbsian ensemble formalism and the
non-equilibrium ensemble formalism. The obtained density distribution is a
projected one that can represent essence part of (irreversible) evolution of
the density distribution, by which a generalized reduced density distribution
for the quantum canonical ensembles is studied and applications in Cayley tree
and spin network are discussed.


title: Manifolds of Hilbert space projections

abstract:
  The Hardy space H^2(R) for the upper half plane together with a unimodular
function group representation u(\lambda) = \exp(i(\lambda_1\psi_1 + ... +
\lambda_n\psi_n)) for \lambda in R^n, gives rise to a manifold M of orthogonal
projections for the subspaces u(\lambda)H^2(R) of L^2(R). For classes of
admissible functions \psi_i the strong operator topology closures of M and M
\cup M^\perp are determined explicitly as various n-balls and n-spheres. The
arguments used are direct and rely on the analysis of oscillatory integrals and
Hilbert space geometry. Some classes of these closed projection manifolds are
classified up to unitary equivalence. In particular the Fourier-Plancherel
2-sphere and the hyperbolic 3-sphere of Katavolos and Power appear as
distinguished special cases admitting nontrivial unitary automorphisms groups
which are explicitly described.


title: Quasi-semi-stable representations

abstract:
  Fix K a p-adic field and denote by G_K its absolute Galois group. Let K_infty
be the extension of K obtained by adding (p^n)-th roots of a fixed uniformizer,
and G_\infty its absolute Galois group. In this article, we define a class of
p-adic torsion representations of G_\infty, named quasi-semi-stable. We prove
that these representations are "explicitly" described by a certain category of
linear algebra objects. The results of this note should be consider as a first
step in the understanding of the structure of quotients of two lattices in a
crystalline (resp. semi-stable) Galois representation.


title:
Coarsening in potential and nonpotential models of oblique stripe
  patterns

abstract:
  We study the coarsening of two-dimensional oblique stripe patterns by
numerically solving potential and nonpotential anisotropic Swift-Hohenberg
equations. Close to onset, all models exhibit isotropic coarsening with a
single characteristic length scale growing in time as $t^{1/2}$. Further from
onset, the characteristic lengths along the preferred directions $\hat{x}$ and
$\hat{y}$ grow with different exponents, close to 1/3 and 1/2, respectively. In
this regime, one-dimensional dynamical scaling relations hold. We draw an
analogy between this problem and Model A in a stationary, modulated external
field. For deep quenches, nonpotential effects produce a complicated
dislocation dynamics that can lead to either arrested or faster-than-power-law
growth, depending on the model considered. In the arrested case, small isolated
domains shrink down to a finite size and fail to disappear. A comparison with
available experimental results of electroconvection in nematics is presented.


title:
Optimized stray-field-induced enhancement of the electron spin
  precession by buried Fe gates

abstract:
  The magnetic stray field from Fe gates is used to modify the spin precession
frequency of InGaAs/GaAs quantum-well electrons in an external magnetic field.
By using an etching process to position the gates directly in the plane of the
quantum well, the stray-field influence on the spin precession increases
significantly compared with results from previous studies with top-gated
structures. In line with numerical simulations, the stray-field-induced
precession frequency increases as the gap between the ferromagnetic gates is
reduced. The inhomogeneous stray field leads to additional spin dephasing.


title:
Electrically probing photonic bandgap phenomena in contacted defect
  nanocavities

abstract:
  We demonstrate an electrically tunable two dimensional photonic crystal
nanocavity containing InAs self assembled quantum dots. Photoluminescence and
electroluminescence measurements are combined to probe the cavity mode
structure and demonstrate a local electrical contact to the quantum dots.
Measurements performed as a function of the electric field enable us to probe
the capture, relaxation and recombination dynamics of photogenerated carriers
inside the quantum dots emitting into a modified photonic environment.
Furthermore, the two dimensional photonic crystal is probed by spatially
dependent photocurrent spectroscopy indicating a 3.5x enhancement of the local
radiative lifetime of the QDs inside the photonic crystal environment.


title: 3D Photoionisation Modelling of NGC 6302

abstract:
  We present a three-dimensional photoionisation and dust radiative transfer
model of NGC 6302, an extreme, high-excitation planetary nebula. We use the 3D
photoionisation code Mocassin} to model the emission from the gas and dust. We
have produced a good fit to the optical emission-line spectrum, from which we
derived a density distribution for the nebula. A fit to the infrared coronal
lines places strong constraints on the properties of the unseen ionising
source. We find the best fit comes from using a 220,000 K hydrogen-deficient
central star model atmosphere, indicating that the central star of this PN may
have undergone a late thermal pulse.
  We have also fitted the overall shape of the ISO spectrum of NGC 6302 using a
dust model with a shallow power-law size distribution and grains up to 1.0
micron in size. To obtain a good fit to the infrared SED the dust must be
sufficiently recessed within the circumstellar disk to prevent large amounts of
hot dust at short wavelengths, a region where the ISO spectrum is particularly
lacking. These and other discoveries are helping to unveil many properties of
this extreme object and trace it's evolutionary history.


title: Impact of community structure on information transfer

abstract:
  The observation that real complex networks have internal structure has
important implication for dynamic processes occurring on such topologies. Here
we investigate the impact of community structure on a model of information
transfer able to deal with both search and congestion simultaneously. We show
that networks with fuzzy community structure are more efficient in terms of
packet delivery that those with pronounced community structure. We also propose
an alternative packet routing algorithm which takes advantage of the knowledge
of communities to improve information transfer and show that in the context of
the model an intermediate level of community structure is optimal. Finally, we
show that in a hierarchical network setting, providing knowledge of communities
at the level of highest modularity will improve network capacity by the largest
amount.


title:
Mechanical losses in low loss materials studied by Cryogenic Resonant
  Acoustic spectroscopy of bulk materials (CRA spectroscopy)

abstract:
  Mechanical losses of crystalline silicon and calcium fluoride have been
analyzed in the temperature range from 5 to 300 K by our novel mechanical
spectroscopy method, cryogenic resonant acoustic spectroscopy of bulk materials
(CRA spectrocopy). The focus lies on the interpretation of the measured data
according to phonon-phonon interactions and defect induced losses in
consideration of the excited mode shape.


title:
Reconstruction accuracy of the surface detector array of the Pierre
  Auger Observatory

abstract:
  The reconstruction of extensive air showers (arrival direction, core position
and energy estimation) by the surface detector of the Pierre Auger Observatory
is discussed together with the corresponding accuracy. We determine the angular
reconstruction accuracy as a function of the station multiplicity by using two
different aproaches. We discuss statistical and systematic uncertainties in the
determination of the signal at 1000 m from the core, S(1000), which is used to
estimate the primary energy.


title: Old open clusters in the outer Galactic disk

abstract:
  The outer parts of the Milky Way disk are believed to be one of the main
arenas where the accretion of external material in the form of dwarf galaxies
and subsequent formation of streams is taking place. The Monoceros stream and
the Canis Major and Argo over-densities are notorious examples. VLT high
resolution spectra have been acquired for five distant open clusters. We derive
accurate radial velocities to distinguish field interlopers and cluster
members. For the latter we perform a detailed abundance analysis and derive the
iron abundance [Fe/H] and the abundance ratios of several $\alpha$ elements.
Our analysis confirms previous indications that the radial abundance gradient
in the outer Galactic disk does not follow the expectations extrapolated from
the solar vicinity, but exhibits a shallower slope. By combining the
metallicity of the five program clusters with eight more clusters for which
high resolution spectroscopy is available, we find that the mean metallicity in
the outer disk between 12 and 21 kpc from the Galactic center is [Fe/H]
$\approx -0.35$, with only marginal indications for a radial variation. In
addition, all the program clusters exhibit solar scaled or slightly enhanced
$\alpha$ elements, similar to open clusters in the solar vicinity and thin disk
stars. We investigate whether this outer disk cluster sample might belong to an
extra-galactic population, like the Monoceros ring. However, close scrutiny of
their properties - location, kinematics and chemistry - does not convincingly
favor this hypothesis. On the contrary, they appear more likely genuine
Galactic disk clusters. We finally stress the importance to obtain proper
motion measurements for these clusters to constrain their orbits.


title: \'Etale cohomology of the complement of a linear subspace arrangement

abstract:
  We prove a formula for the cup product on the l-adic cohomology of the
complement of a linear subspace arrangement.


title: D-branes, KK-theory and duality on noncommutative spaces

abstract:
  We present a new categorical classification framework for D-brane charges on
noncommutative manifolds using methods of bivariant K-theory. We describe
several applications including an explicit formula for D-brane charge in cyclic
homology, a refinement of open string T-duality, and a general criterion for
cancellation of global worldsheet anomalies.


title: Loop Quantum Dynamics of the Schwarzschild Interior

abstract:
  We examine the Schwarzschild interior of a black hole, incorporating quantum
gravitational modifications due to loop quantum gravity. We consider an
improved loop quantization using techniques that have proven successful in loop
quantum cosmology. The central Schwarzschild singularity is resolved and the
implications for the fate of an in-falling test particle in the interior region
is discussed. The singularity is replaced by a Nariai type Universe. We discuss
the resulting conformal diagram, providing a clear geometrical interpretation
of the quantum effects.


title:
Effective growth of matter density fluctuations in the running LCDM and
  LXCDM models

abstract:
  We investigate the matter density fluctuations \delta\rho/\rho for two dark
energy (DE) models in the literature in which the cosmological term \Lambda is
a running parameter. In the first model, the running LCDM model, matter and DE
exchange energy, whereas in the second model, the LXCDM model, the total DE and
matter components are conserved separately. The LXCDM model was proposed as an
interesting solution to the cosmic coincidence problem. It includes an extra
dynamical component, the "cosmon" X, which interacts with the running \Lambda,
but not with matter. In our analysis we make use of the current value of the
linear bias parameter, b^2(0)= P_{GG}/P_{MM}, where P_{MM} ~
(\delta\rho/\rho)^2 is the present matter power spectrum and P_{GG} is the
galaxy fluctuation power spectrum. The former can be computed within a given
model, and the latter is found from the observed LSS data (at small z) obtained
by the 2dF galaxy redshift survey. It is found that b^2(0)=1 within a 10%
accuracy for the standard LCDM model. Adopting this limit for any DE model and
using a method based on the effective equation of state for the DE, we can set
a limit on the growth of matter density perturbations for the running LCDM
model, the solution of which is known. This provides a good test of the
procedure, which we then apply to the LXCDM model in order to determine the
physical region of parameter space, compatible with the LSS data. In this
region, the LXCDM model is consistent with known observations and provides at
the same time a viable solution to the cosmic coincidence problem.


title: Gravitational dynamics in s+1+1 dimensions II. Hamiltonian theory

abstract:
  We develop a Hamiltonian formalism of brane-world gravity, which singles out
two preferred, mutually orthogonal directions. One is a unit twist-free field
of spatial vectors with integral lines intersecting perpendicularly the brane.
The other is a temporal vector field with respect to which we perform the
Arnowitt-Deser-Misner decomposition of the Einstein-Hilbert Lagrangian. The
gravitational variables arise from the projections of the spatial metric and
their canonically conjugated momenta as tensorial, vectorial and scalar
quantities defined on the family of hypersurfaces containing the brane. They
represent the gravitons, a gravi-photon and a gravi-scalar, respectively. From
the action we derive the canonical evolution equations and the constraints for
these gravitational degrees of freedom both on the brane and outside it. By
integrating across the brane, the dynamics also generates the tensorial and
scalar projection of the Lanczos equation. The vectorial projection of the
Lanczos equation arises in a similar way from the diffeomorphism constraint.
Both the graviton and the gravi-scalar are continuous across the brane, however
the momentum of the gravi-vector has a jump, related to the energy transport
(heat flow) on the brane.


title: Dynamics of vortices in weakly interacting Bose-Einstein condensates

abstract:
  We study the dynamics of vortices in ideal and weakly interacting
Bose-Einstein condensates using a Ritz minimization method to solve the
two-dimensional Gross-Pitaevskii equation. For different initial vortex
configurations we calculate the trajectories of the vortices. We find
conditions under which a vortex-antivortex pair annihilates and is created
again. For the case of three vortices we show that at certain times two
additional vortices may be created, which move through the condensate and
annihilate each other again. For a noninteracting condensate this process is
periodic, whereas for small interactions the essential features persist, but
the periodicity is lost. The results are compared to exact numerical solutions
of the Gross-Pitaevskii equation confirming our analytical findings.


title:
3C 40 in Abell 194: can tail radio galaxies exist in a quiescent
  cluster?

abstract:
  The nearby cluster Abell 194 hosts two luminous, distorted radio galaxies.
Both reside within the cluster's core region, being separated in projection by
only 100 kpc. It is often suggested that tailed radio galaxies such as these
reside in clusters that are under formation and are accreting new material from
their outskirts. In this paper we study the intriguing appearance of Abell 194,
and test whether the cluster and radio source dynamics are consistent with the
cluster formation/merger model. We analyse data from the XMM-Newton satellite
and previously unpublished observations with the Very Large Array (VLA), as
well as presenting new data from the Giant Metre-Wave Radio Telescope (GMRT).
The shape of the jets, and the lack of significant stripping of the galaxies'
interstellar media, indicate that the radio galaxies are not moving at the
large velocities they would have had if they were falling into the cluster from
its outskirts; galaxy velocities of <=300 km s^-1 are adequate instead. A
plausible scenario that could explain the observations is that the dynamics of
the cluster centre are relatively quiescent, with the dominant system of
massive galaxies being bound and orbiting the cluster centre of mass. For
plausible jet/plume speeds and densities and the galaxy dynamics implied by
this picture of the cluster, we show that the observed jet structures can be
explained without invoking a major cluster merger event.


title: Search for excited spin-3/2 and spin-1/2 leptons at linear colliders

abstract:
  We study the single production of excited spin-3/2 and spin-1/2 leptons in
future high energy $e^+e^-$ collisions. We calculate the production cross
section and decay widths of excited spin-3/2 and spin-1/2 leptons according to
their effective currents. We show that these possible new excited states can be
probed up to the mass $m^*$ ~ $\sqrt{s}$ depending on their couplings to
leptons and gauge bosons. We present the angular distributions of final state
particles as a measure to discriminate between an excited spin-3/2 and spin-1/2
lepton signal. The signals and the corresponding backgrounds are studied in
detail to obtain attainable limits on masses and couplings of excited leptons
at future linear colliders


title: Coupling Superconducting Qubits via a Cavity Bus

abstract:
  Superconducting circuits are promising candidates for constructing quantum
bits (qubits) in a quantum computer; single-qubit operations are now routine,
and several examples of two qubit interactions and gates having been
demonstrated. These experiments show that two nearby qubits can be readily
coupled with local interactions. Performing gates between an arbitrary pair of
distant qubits is highly desirable for any quantum computer architecture, but
has not yet been demonstrated. An efficient way to achieve this goal is to
couple the qubits to a quantum bus, which distributes quantum information among
the qubits. Here we show the implementation of such a quantum bus, using
microwave photons confined in a transmission line cavity, to couple two
superconducting qubits on opposite sides of a chip. The interaction is mediated
by the exchange of virtual rather than real photons, avoiding cavity induced
loss. Using fast control of the qubits to switch the coupling effectively on
and off, we demonstrate coherent transfer of quantum states between the qubits.
The cavity is also used to perform multiplexed control and measurement of the
qubit states. This approach can be expanded to more than two qubits, and is an
attractive architecture for quantum information processing on a chip.


title: The Geometric Phase and Gravitational Precession of D-Branes

abstract:
  We study Berry's phase in the D0-D4-brane system. When a D0-brane moves in
the background of D4-branes, the first excited states undergo a holonomy
described by a non-Abelian Berry connection. At weak coupling this is an SU(2)
connection over R^5, known as the Yang monopole. At strong coupling, the
holonomy is recast as the classical gravitational precession of a spinning
particle. The Berry connection is the spin connection of the near-horizon limit
of the D4-branes, which is a continuous deformation of the Yang and anti-Yang
monopole.


title:
The influence of pairing on the nuclear matrix elements of the
  neutrinoless double beta decays

abstract:
  We study in this letter the behavior of the neutrinoless double beta decay
nuclear matrix elements (NME's) in the framework of the Interacting Shell
Model. We analize them in terms of the total angular momentum of the decaying
neutron pair and as a function of the seniority truncations in the nuclear wave
functions. This point of view turns out to be very adequate to gauge the
accuracy of the NME's predicted by different nuclear structure models. In
addition, it gives back the due protagonism in this process to the pairing
interaction, the interaction which is responsible for the very existence of
double beta decay emitters. We show that low seniority approximations,
comparable to those implicit in the quasiparticle RPA in an spherical basis,
tend to overestimate the values of the NME's in several decays.


title: Dynamical Emergence of Complex Structures in Field Theories

abstract:
  Nonlinear field theories can be used to study both standard physics
questions, or to study questions such as the emergence of order and complexity.
These theories are generally derived from the symmetries of a given problem and
the interactions that respect those symmetries. Formally one can then quantize
the system to find the masses of the fundamental excitations, but this
procedure generally destroys much information about solutions of the field
equations with large non-perturbative amplitudes. To get information about the
properties of the solutions to these field theories without perturbative
approximations we use real time lattice simulations where complex
spatiotemporal structures emerge dynamically from excess free energy and a
thermal background. We present results in 2 and 3 dimensions of new interacting
quasi-particle formations from a quench. These objects show an emergent level
of complexity which we attempt to categorize and define in a manner that should
be useful to many different applications.


title: Spectral functions for medium-sized nuclei

abstract:
  The spectral functions for calcium and argon are constructed. It is verified
that their predictions for the quasielastic electron-nucleus cross sections in
the energy range ~1 GeV agree with the data. The argon spectral function is
then used to obtain the quasielastic neutrino-nucleus cross section.


title: Entanglement as a Probe of Confinement

abstract:
  We investigate the entanglement entropy in gravity duals of confining large
$N_c$ gauge theories using the proposal of arXiv:hep-th/0603001,
arXiv:hep-th/0605073. Dividing one of the directions of space into a line
segment of length $l$ and its complement, the entanglement entropy between the
two subspaces is given by the classical action of the minimal bulk hypersurface
which approaches the endpoints of the line segment at the boundary. We find
that in confining backgrounds there are generally two such surfaces. One
consists of two disconnected components localized at the endpoints of the line
segment. The other contains a tube connecting the two components. The
disconnected surface dominates the entropy for $l$ above a certain critical
value $l_{\rm crit}$ while the connected one dominates below that value. The
change of behavior at $l=l_{\rm crit}$ is reminiscent of the finite temperature
deconfinement transition: for $l < l_{\rm crit}$ the entropy scales as $N_c^2$,
while for $l > l_{\rm crit}$ as $N_c^0$. We argue that a similar transition
should occur in any field theory with a Hagedorn spectrum of non-interacting
bound states. The requirement that the entanglement entropy has a phase
transition may be useful in constraining gravity duals of confining theories.


title: A skein approach to Bennequin type inequalities

abstract:
  We give a simple unified proof for several disparate bounds on
Thurston-Bennequin number for Legendrian knots and self-linking number for
transverse knots in R^3, and provide a template for possible future bounds. As
an application, we give sufficient conditions for some of these bounds to be
sharp.


title: The Rotation Period of the Planet-Hosting Star HD 189733

abstract:
  We present synoptic optical photometry of HD 189733, the chromospherically
active parent star of one of the most intensively studied exoplanets. We have
significantly extended the timespan of our previously reported observations and
refined the estimate of the stellar rotation period by more than an order of
magnitude: $P = 11.953\pm 0.009$ days. We derive a lower limit on the
inclination of the stellar rotation axis of $56\arcdeg$ (with 95% confidence),
corroborating earlier evidence that the stellar spin axis and planetary orbital
axis are well aligned.


title:
Optimized Double-well quantum interferometry with Gaussian
  squeezed-states

abstract:
  A Mach-Zender interferometer with a gaussian number-difference squeezed input
state can exhibit sub-shot-noise phase resolution over a large phase-interval.
We obtain the optimal level of squeezing for a given phase-interval
$\Delta\theta_0$ and particle number $N$, with the resulting phase-estimation
uncertainty smoothly approaching $3.5/N$ as $\Delta\theta_0$ approaches 10/N,
achieved with highly squeezed states near the Fock regime. We then analyze an
adaptive measurement scheme which allows any phase on $(-\pi/2,\pi/2)$ to be
measured with a precision of $3.5/N$ requiring only a few measurements, even
for very large $N$. We obtain an asymptotic scaling law of $\Delta\theta\approx
(2.1+3.2\ln(\ln(N_{tot}\tan\Delta\theta_0)))/N_{tot}$, resulting in a final
precision of $\approx 10/N_{tot}$. This scheme can be readily implemented in a
double-well Bose-Einstein condensate system, as the optimal input states can be
obtained by adiabatic manipulation of the double-well ground state.


title:
On-demand generation of entanglement of atomic qubits via optical
  interferometry

abstract:
  The problem of on-demand generation of entanglement between single-atom
qubits via a common photonic channel is examined within the framework of
optical interferometry. As expected, for a Mach-Zehnder interferometer with
coherent laser beam as input, a high-finesse optical cavity is required to
overcome sensitivity to spontaneous emission. We show, however, that with a
twin-Fock input, useful entanglement can in principle be created without
cavity-enhancement. Both approaches require single-photon resolving detectors,
and best results would be obtained by combining both cavity-feedback and
twin-Fock inputs. Such an approach may allow a fidelity of $.99$ using a
two-photon input and currently available mirror and detector technology. In
addition, we study interferometers based on NOON states and show that they
perform similarly to the twin-Fock states, yet without the need for
high-precision photo-detectors. The present interferometrical approach can
serve as a universal, scalable circuit element for quantum information
processing, from which fast quantum gates, deterministic teleportation,
entanglement swapping $etc.$, can be realized with the aid of single-qubit
operations.


title: Line emission from optically thick relativistic accretion tori

abstract:
  We calculate line emission from relativistic accretion tori around Kerr black
holes and investigate how the line profiles depend on the viewing inclination,
spin of the central black hole, parameters describing the shape of the tori,
and spatial distribution of line emissivity on the torus surface. We also
compare the lines with those from thin accretion disks. Our calculations show
that lines from tori and lines from thin disks share several common features.
In particular, at low and moderate viewing inclination angles they both have
asymmetric double-peaked profiles with a tall, sharp blue peak and a shorter
red peak which has an extensive red wing. At high viewing inclination angles
they both have very broad, asymmetric lines which can be roughly considered
single-peaked. Torus and disk lines may show very different red and blue line
wings, but the differences are due to the models for relativistic tori and
disks having differing inner boundary radii. Self-eclipse and lensing play some
role in shaping the torus lines, but they are effective only at high
inclination angles. If inner and outer radii of an accretion torus are the same
as those of an accretion disk, their line profiles show substantial differences
only when inclination angles are close to 90 degrees, and those differences
manifest mostly at the central regions of the lines instead of the wings.


title:
High frequency EPR on dilute solutions of the single molecule magnet
  Ni$_4$

abstract:
  Dilute frozen solutions of the single molecule magnet Ni$_4$ (S=4) have been
studied using high frequency D-band (130 GHz) EPR. Despite the random
orientation of the molecules, well defined EPR absorption peaks are observed,
due to the strong variation of the splittings between the different spin-states
on magnetic field. Temperature dependent studies above 4 K and comparison with
simulations enable identification of the spin transitions and determination of
the Hamiltonian parameters. The latter are found to be close to those of Ni$_4$
single crystals. No echo was detected from Ni$_4$ in pulsed experiments, which
sets an upper bound of about 50 ns on the spin coherence time.


title:
Argon Abundances in the Solar Neighborhood: Non-LTE Analysis of Orion
  Association B-type Stars

abstract:
  Argon abundances have been derived for a sample of B main-sequence stars in
the Orion association. The abundance calculations are based on NLTE metal
line-blanketed model atmospheres calculated with the NLTE code TLUSTY and an
updated and complete argon model atom. We derive an average argon abundance for
this young population of A(Ar) = 6.66 +- 0.06. While our result is in excellent
agreement with a recent analysis of the Orion nebula, it is significantly
higher than the currently recommended solar value which is based on abundance
measurements in the solar corona. Moreover, the derived argon abundances in the
Orion B stars agree very well with a measurement from a solar impulsive flare
during which unmodified solar photospheric material was brought to flare
conditions. We therefore argue that the argon abundances obtained independently
for both the Orion B stars and the Orion nebula are representative of the disk
abundance value in the solar neighborhood. The lower coronal abundance may
reflect a depletion related to the FIP effect. We propose a new reference value
for the abundance of argon in the solar neighborhood, A(Ar) = 6.63 +- 0.10,
corresponding to Ar/O = 0.009.


title: New Constructions of Slice Links

abstract:
  We use techniques of Freedman and Teichner to prove that, under certain
circumstances, the multi-infection of a slice link is again slice (not
necessarily smoothly slice). We provide a general context for proving links are
slice that includes many of the previously known results.


title: Rigid Dualizing Complexes via Differential Graded Algebras (Survey)

abstract:
  In this article we survey recent results on rigid dualizing complexes over
commutative algebras. We begin by recalling what are dualizing complexes. Next
we define rigid complexes, and explain their functorial properties. Due to the
possible presence of torsion, we must use differential graded algebras in the
constructions. We then discuss rigid dualizing complexes. Finally we show how
rigid complexes can be used to understand Cohen-Macaulay homomorphisms and
relative dualizing sheaves.


title:
A comment on "Computational periodicity as observed in a simple system,"
  by Edward N. Lorenz (2006a)

abstract: This paper has been withdrawn by the authors as requested by the journal.


title:
Eigenvalue estimates for the scattering problem associated to the
  sine-Gordon equation

abstract:
  One of the difficulties associated with the scattering problems arising in
connection with integrable systems is that they are frequently
non-self-adjoint, making it difficult to determine where the spectrum lies. In
this paper, we consider the problem of locating and counting the discrete
eigenvalues associated with the scattering problem for which the sine-Gordon
equation is the isospectral flow. In particular, suppose that we take an
initially stationary pulse for the sine-Gordon equation, with a profile that
has either one extremum point of height less than pi and topological charge 0,
or is monotone with topological charge +-1. Then we show that the point
spectrum lies on the unit circle and is simple. Furthermore, we give a count of
the number of eigenvalues. This result is an analog of that of Klaus and Shaw
for the Zakharov-Shabat scattering problem. We also relate our results, as well
as those of Klaus and Shaw, to the Krein stability theory for symplectic
matrices. In particular we show that the scattering problem associated to the
sine-Gordon equation has a symplectic structure, and under the above conditions
the point eigenvalues have a definite Krein signature, and are thus simple and
lie on the unit circle.


title: Heating Hot Atmospheres with Active Galactic Nuclei

abstract:
  High resolution X-ray spectroscopy of the hot gas in galaxy clusters has
shown that the gas is not cooling to low temperatures at the predicted rates of
hundreds to thousands of solar masses per year. X-ray images have revealed
giant cavities and shock fronts in the hot gas that provide a direct and
relatively reliable means of measuring the energy injected into hot atmospheres
by active galactic nuclei (AGN). Average radio jet powers are near those
required to offset radiative losses and to suppress cooling in isolated giant
elliptical galaxies, and in larger systems up to the richest galaxy clusters.
This coincidence suggests that heating and cooling are coupled by feedback,
which suppresses star formation and the growth of luminous galaxies. How jet
energy is converted to heat and the degree to which other heating mechanisms
are contributing, eg. thermal conduction, are not well understood. Outburst
energies require substantial late growth of supermassive black holes. Unless
all of the approximately 10E62 erg required to suppress star formation is
deposited in the cooling regions of clusters, AGN outbursts must alter
large-scale properties of the intracluster medium.


title: Generalized Vandermonde's system and Lagrange's interpolation

abstract:
  We give explicit formulas as well as a quadratic time algorithm to solve (so
called) generalized Vandermonde's systems of p linear equations and n
variables. It allows in particular to find all (so called Lagrange's)
interpolation polynoms with degree n-1 taking given values in p distinct
points.


title: The AMS-RICH velocity and charge reconstruction

abstract:
  The AMS detector, to be installed on the International Space Station,
includes a Ring Imaging Cerenkov detector with two different radiators, silica
aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to
provide very precise measurements of velocity and electric charge in a wide
range of cosmic nuclei energies and atomic numbers. The detector geometry, in
particular the presence of a reflector for acceptance purposes, leads to
complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The
results of different reconstruction methods applied to test beam data as well
as to simulated samples are presented. To ensure nominal performances
throughout the flight, several detector parameters have to be carefully
monitored. The algorithms developed to fulfill these requirements are
presented. The velocity and charge measurements provided by the RICH detector
endow the AMS spectrometer with precise particle identification capabilities in
a wide energy range. The expected performances on light isotope separation are
discussed.


title: A general learning algorithm for functions between metric spaces

abstract:
  In this paper we show how to approximate ("learn") a function f, where X and
Y are metric spaces.


title: The Candy-Passing Game for c\geq3n-2

abstract:
  We determine the behavior of Tanton's candy-passing game for all
distributions of at least 3n-2 candies, where n is the number of students.
Specifically, we show that the configuration of candy in such a game eventually
becomes fixed.


title:
Spontaneous Transverse Response and Amplified Switching in
  Superconductors with Honeycomb Pinning Arrays

abstract:
  Using numerical simulations, we show that a novel spontaneous transverse
response can appear when a longitudinal drive is applied to type-II
superconductors with honeycomb pinning arrays in a magnetic field near certain
filling fractions. This response is generated by dynamical symmetry breaking
that occurs at fields away from commensurability. We find a coherent strongly
amplified transverse switching effect when an additional transverse ac current
is applied. The transverse ac drive can also be used to control switching in
the longitudinal velocity response. We discuss how these effects could be used
to create new types of devices such as current effect transistors.


title: Branes, Anti-Branes and Brauer Algebras in Gauge-Gravity duality

abstract:
  We propose gauge theory operators built using a complex Matrix scalar which
are dual to brane-anti-brane systems in $AdS_5 \times S^5 $, in the zero
coupling limit of the dual Yang-Mills. The branes involved are half-BPS giant
gravitons. The proposed operators dual to giant-anti-giant configurations
satisfy the appropriate orthogonality properties. Projection operators in
Brauer algebras are used to construct the relevant multi-trace Matrix
operators. These are related to the ``coupled representations'' which appear in
2D Yang-Mills theory. We discuss the implications of these results for the
quantum mechanics of a complex matrix model, the counting of non-supersymmetric
operators and the physics of brane-anti-brane systems. The stringy exclusion
principle known from the properties of half-BPS giant gravitons, has a new
incarnation in this context. It involves a qualitative change in the map
between brane-anti-brane states to gauge theory operators. In the case of a
pair of sphere giant and anti-giant this change occurs when the sum of the
magnitudes of their angular momenta reaches $N$.


title:
On the application of the Critical Minimum Energy Subspace method to
  disordered systems

abstract:
  We discuss the recent application to strongly disordered systems of the
Critical Minimum Energy Subspace (CMES) method, used to limit the energy
subspace of the Wang-Landau sampling. We compare with our results on the 3D
Random Field Ising Model obtained by a multi-range Wang-Landau simulation in
the whole energy range. We point out at some problems that may arise when
applying the CMES scheme to models having a complex free energy landscape. PACS
numbers: 02.70.Tt,02.70.Rr,05.50.+q, 64.60.Cn, 64.60.Fr, 75.10.Hk


title: High-spin binary black hole mergers

abstract:
  We study identical mass black hole binaries with spins perpendicular to the
binary's orbital plane. These binaries have individual spins ranging from
$s/m^2=-0.90$ to 0.90, ($s_1 = s_2$ in all cases) which is near the limit
possible with standard Bowen-York puncture initial data. The extreme cases
correspond to the largest initial spin simulations to date. Our results expand
the parameter space covered by Rezzolla {\it et al.} and, when combining both
data sets, we obtain estimations for the minimum and maximum values for the
intrinsic angular momenta of the remnant of binary black hole mergers of
$J/M^2=0.341 \pm 0.004$ and $0.951 \pm 0.004$ respectively. Note, however, that
these values are reached through extrapolation to the singular cases $|s_1| =
|s_2| = 1$ and thus remain as {\it estimates} until full-fledged numerical
simulations provide confirmation.


title: Hyperbolic Unit Groups and Quaternion Algebras

abstract:
  We Classify the rational quadratic extensions K and the finite groups G for
which the group ring R[G] of G over the ring R of integers of K has the
property that the group of units of augmentation 1 of R[G] is hyperbolic. We
also construct units in a non-split quaternion algebra over R.


title: Closed-String Tachyon Condensation and the Worldsheet Super-Higgs Effect

abstract:
  Alternative gauge choices for worldsheet supersymmetry can elucidate
dynamical phenomena obscured in the usual superconformal gauge. In the
particular example of the tachyonic $E_8$ heterotic string, we use a judicious
gauge choice to show that the process of closed-string tachyon condensation can
be understood in terms of a worldsheet super-Higgs effect. The worldsheet
gravitino assimilates the goldstino and becomes a dynamical propagating field.
Conformal, but not superconformal, invariance is maintained throughout.


title: Neutrino Oscillation Observables from Mass Matrix Structure

abstract:
  We present a systematic procedure to establish a connection between complex
neutrino mass matrix textures and experimental observables, including the Dirac
CP phase. In addition, we illustrate how future experimental measurements
affect the selection of textures in the (theta_13,delta_CP)-plane. For the
mixing angles, we use generic assumptions motivated by quark-lepton
complementarity. We allow for any combination between U_l and U_nu, as well as
we average over all present complex phases. We find that individual textures
lead to very different distributions of the observables, such as to large or
small leptonic CP violation. In addition, we find that the extended
quark-lepton complementarity approach motivates future precision measurements
of delta_CP at the level of theta_C \simeq 11 degrees.


title: Extra dimensions, orthopositronium decay, and stellar cooling

abstract:
  In a class of extra dimensional models with a warped metric and a single
brane the photon can be localized on the brane by gravity only. An intriguing
feature of these models is the possibility of the photon escaping into the
extra dimensions. The search for this effect has motivated the present round of
precision orthopositronium decay experiments. We point out that in this
framework a photon in plasma should be metastable. We consider the
astrophysical consequences of this observation, in particular, what it implies
for the plasmon decay rate in globular cluster stars and for the core-collapse
supernova cooling rate. The resulting bounds on the model parameter exceed the
possible reach of orthopositronium experiments by many orders of magnitude.


title: Lighting the Universe with filaments

abstract:
  The first stars in the Universe form when chemically pristine gas heats as it
falls into dark matter potential wells, cools radiatively due to the formation
of molecular hydrogen, and becomes self-gravitating. We demonstrate with
super-computer simulations that their properties depend critically on the
currently unknown nature of the dark matter. If the dark matter particles have
intrinsic velocities that wipe-out small-scale structure, then the first stars
form in filaments with lengths of order the free-streaming scale, which can be
about 10^20m (~3kpc, baryonic masses 10^7 solar masses) for realistic "warm
dark matter" candidates. Fragmentation of the filaments forms stars with a
range of masses which may explain the observed peculiar element abundance
pattern of extremely metal-poor stars, while coalescence of fragments and stars
during the filament's ultimate collapse may seed the super massive black holes
that lurk in the centres of most massive galaxies.


title: Supercritical N = 2 string theory

abstract:
  The N=2 string is examined in dimensions above the critical dimension (D=4)
in a linear dilaton background. We demonstrate that string states in this
background propagate in a single physical time dimension, as opposed to two
such dimensions present when the dilaton gradient vanishes in D=4. We also find
exact solutions describing dynamical dimensional reduction and transitions from
N=2 string theory to bosonic string theory via closed-string tachyon
condensation.


title:
The Lifetime of FRIIs in Groups and Clusters: Implications for
  Radio-Mode Feedback

abstract:
  We determine the maximum lifetime t_max of 52 FRII radio sources found in 26
central group galaxies from cross correlation of the Berlind SDSS group catalog
with the VLA FIRST survey. Mock catalogs of FRII sources were produced to match
the selection criteria of FIRST and the redshift distribution of our parent
sample, while an analytical model was used to calculate source sizes and
luminosities. The maximum lifetime of FRII sources was then determined via a
comparison of the observed and model projected length distributions. We
estimate the average FRII lifetime is 1.5x10^7 years and the duty cycle is
~8x10^8 years. Degeneracies between t_max and the model parameters: jet power
distribution, axial ratio, energy injection index, and ambient density
introduce at most a factor of two uncertainty in our lifetime estimate. In
addition, we calculate the radio active galactic nuclei (AGN) fraction in
central group galaxies as a function of several group and host galaxy
properties. The lifetime of radio sources recorded here is consistent with the
quasar lifetime, even though these FRIIs have substantially sub-Eddington
accretion. These results suggest a fiducial time frame for energy injection
from AGN in feedback models. If the morphology of a given extended radio source
is set by large-scale environment, while the lifetime is determined by the
details of the accretion physics, this FRII lifetime is relevant for all
extended radio sources.


title: Bright branes for strongly coupled plasmas

abstract:
  We use holographic techniques to study photon production in a class of finite
temperature, strongly coupled, large-Nc SU(Nc) quark-gluon plasmas with Nf <<
Nc quark flavours. Our results are valid to leading order in the
electromagnetic coupling constant but non-perturbatively in the SU(Nc)
interactions. The spectral function of electromagnetic currents and other
related observables exhibit an interesting structure as a function of the
photon frequency and the quark mass. We discuss possible implications for heavy
ion collision experiments.


title: Basins of attraction of a nonlinear nanomechanical resonator

abstract:
  We present an experiment that systematically probes the basins of attraction
of two fixed points of a nonlinear nanomechanical resonator and maps them out
with high resolution. We observe a separatrix which progressively alters shape
for varying drive strength and changes the relative areas of the two basins of
attraction. The observed separatrix is blurred due to ambient fluctuations,
including residual noise in the drive system, which cause uncertainty in the
preparation of an initial state close to the separatrix. We find a good
agreement between the experimentally mapped and theoretically calculated basins
of attraction.


title:
Physical Degrees of Freedom of the Relativistic Fluid on K\"{a}hler
  Manifolds in the Symplectic Projector Approach

abstract:
  The paper has been withdrawn because of a more complete analysis of the
relativistic fluid including the quantization reported in arxiv:0801.3032
[hep-th].


title: Inverse spectral problems on a closed manifold

abstract:
  In this paper we consider two inverse problems on a closed connected
Riemannian manifold $(M,g)$. The first one is a direct analog of the Gel'fand
inverse boundary spectral problem. To formulate it, assume that $M$ is divided
by a hypersurface $\Sigma$ into two components and we know the eigenvalues
$\lambda_j$ of the Laplace operator on $(M,g)$ and also the Cauchy data, on
$\Sigma$, of the corresponding eigenfunctions $\phi_j$, i.e.
$\phi_j|_{\Sigma},\partial_\nu\phi_j|_{\Sigma}$, where $\nu$ is the normal to
$\Sigma$. We prove that these data determine $(M,g)$ uniquely, i.e. up to an
isometry. In the second problem we are given much less data, namely,
$\lambda_j$ and $\phi_j|_{\Sigma}$ only. However, if $\Sigma$ consists of at
least two components, $\Sigma_1, \Sigma_2$, we are still able to determine
$(M,g)$ assuming some conditions on $M$ and $\Sigma$. These conditions are
formulated in terms of the spectra of the manifolds with boundary obtained by
cutting $M$ along $\Sigma_i$, $i=1,2$, and are of a generic nature. We consider
also some other inverse problems on $M$ related to the above with data which is
easier to obtain from measurements than the spectral data described.


title:
The influence of metallic particle size on the mechanical properties of
  PTFE-Al-W powder composites

abstract:
  The dynamic mechanical properties of reactive materials (e.g., high density
mixtures of polytetraflouroethylene (PTFE), aluminum (Al) and tungsten (W)
powders) can be tailored by changing the morphology of the particles and
porosity. Cold isostatically pressed PTFE-Al-W powder composites with fine
metallic particles and a higher porosity exhibited higher ultimate compressive
strength than less porous composites having equivalent mass ratios with coarse
W particles. The mesoscale force chains between the fine metallic particles are
responsible for this unusual phenomenon. We observed macrocracks below the
critical failure strain for the matrix and a competition between densification
and fracture in some porous samples in dynamic tests.


title: Stabilization for mapping class groups of 3-manifolds

abstract:
  We prove that the homology of the mapping class group of any 3-manifold
stabilizes under connected sum and boundary connected sum with an arbitrary
3-manifold when both manifolds are compact and orientable. The stabilization
also holds for the quotient group by twists along spheres and disks, and
includes as particular cases homological stability for symmetric automorphisms
of free groups, automorphisms of certain free products, and handlebody mapping
class groups. Our methods also apply to manifolds of other dimensions in the
case of stabilization by punctures.


title: Topological rigidity for holomorphic foliations

abstract:
  We study analytic deformations and unfoldings of holomorphic foliations in
complex projective plane $\mathbb{C}P(2)$. Let $\{\mathcal{F}_t\}_{t \in
\mathbb{D}_{\epsilon}}$ be topological trivial (in $\mathbb{C}^2$) analytic
deformation of a foliation $\mathcal{F}_0$ on $\mathbb{C}^2$. We show that
under some dynamical restriction on $\mathcal{F}_0$, we have two possibilities:
$\mathcal{F}_0$ is a Darboux (logarithmic) foliation, or $\{\mathcal{F}_t\}_{t
\in \mathbb{D}_{\epsilon}}$ is an unfolding. We obtain in this way a link
between the analytical classification of the unfolding and the one of its germs
at the singularities on the infinity line. Also we prove that a finitely
generated subgroup of $\mathrm{Diff}(\mathbb{C}^n,0)$ with polynomial growth is
solvable.