title:
Dynamical properties and structure of Julia sets of postcritically
  bounded polynomial semigroups

abstract:
  We discuss the dynamic and structural properties of polynomial semigroups, a
natural extension of iteration theory to random (walk) dynamics, where the
semigroup $G$ of complex polynomials (under the operation of composition of
functions) is such that there exists a bounded set in the plane which contains
any finite critical value of any map $g \in G$. In general, the Julia set of
such a semigroup $G$ may be disconnected, and each Fatou component of such $G$
is either simply connected or doubly connected (\cite{Su01,Su9}). In this
paper, we show that for any two distinct Fatou components of certain types
(e.g., two doubly connected components of the Fatou set), the boundaries are
separated by a Cantor set of quasicircles (with uniform dilatation) inside the
Julia set of $G.$ Important in this theory is the understanding of various
situations which can and cannot occur with respect to how the Julia sets of the
maps $g \in G$ are distributed within the Julia set of the entire semigroup
$G$. We give several results in this direction and show how such results are
used to generate (semi) hyperbolic semigroups possessing this postcritically
boundedness condition.


title: Strong wavefront lemma and counting lattice points in sectors

abstract:
  We compute the asymptotics of the number of integral quadratic forms with
prescribed orthogonal decompositions and, more generally, the asymptotics of
the number of lattice points lying in sectors of affine symmetric spaces. A new
key ingredient in this article is the strong wavefront lemma, which shows that
the generalized Cartan decomposition associated to a symmetric space is
uniformly Lipschitz.


title: Beauty in the Standard Model and Beyond

abstract:
  The study of CP violation in the B system allows us to perform quantitative
tests of the CP symmetry in the Standard Model. Many precise measurements of
the sides and angles of the Unitarity Triangle used to test the theory are made
possible by the abundant experimental data accumulated at the B factories and
the Tevatron. I review the Standard Model description of CP violation and the
key measurements which allow us to use CP violation studies as a probe for New
Physics.


title:
Detecting Infinitely Many Semisimple Representations in a Fixed Finite
  Dimension

abstract:
  Let $n$ be a positive integer, and let $k$ be a field (of arbitrary
characteristic) accessible to symbolic computation. We describe an algorithmic
test for determining whether or not a finitely presented $k$-algebra $R$ has
infinitely many equivalence classes of semisimple representations $R \to
M_n(k')$, where $k'$ is the algebraic closure of $k$. The test reduces the
problem to computational commutative algebra over $k$, via famous results of
Artin, Procesi, and Shirshov. The test is illustrated by explicit examples,
with $n = 3$.


title: Cohomology and Support Varieties for Lie Superalgebras II

abstract:
  In \cite{BKN} the authors initiated a study of the representation theory of
classical Lie superalgebras via a cohomological approach. Detecting subalgebras
were constructed and a theory of support varieties was developed. The dimension
of a detecting subalgebra coincides with the defect of the Lie superalgebra and
the dimension of the support variety for a simple supermodule was conjectured
to equal the atypicality of the supermodule. In this paper the authors compute
the support varieties for Kac supermodules for Type I Lie superalgebras and the
simple supermodules for $\mathfrak{gl}(m|n)$. The latter result verifies our
earlier conjecture for $\mathfrak{gl}(m|n)$. In our investigation we also
delineate several of the major differences between Type I versus Type II
classical Lie superalgebras. Finally, the connection between atypicality,
defect and superdimension is made more precise by using the theory of support
varieties and representations of Clifford superalgebras.


title: Uniformly perfect analytic and conformal attractor sets

abstract:
  Conditions are given which imply that analytic iterated function systems
(IFS's) in the complex plane have uniformly perfect attractor sets. In
particular, it is shown that the attractor set of a finitely generated
conformal IFS is uniformly perfect when it contains two or more points. Also,
an example of a finitely generated analytic attractor set which is not
uniformly perfect is given.


title:
Discrete rearranging disordered patterns, part I: Robust statistical
  tools in two or three dimensions

abstract:
  Discrete rearranging patterns include cellular patterns, for instance liquid
foams, biological tissues, grains in polycrystals; assemblies of particles such
as beads, granular materials, colloids, molecules, atoms; and interconnected
networks. Such a pattern can be described as a list of links between
neighbouring sites. Performing statistics on the links between neighbouring
sites yields average quantities (hereafter "tools") as the result of direct
measurements on images. These descriptive tools are flexible and suitable for
various problems where quantitative measurements are required, whether in two
or in three dimensions. Here, we present a coherent set of robust tools, in
three steps. First, we revisit the definitions of three existing tools based on
the texture matrix. Second, thanks to their more general definition, we embed
these three tools in a self-consistent formalism, which includes three
additional ones. Third, we show that the six tools together provide a direct
correspondence between a small scale, where they quantify the discrete
pattern's local distortion and rearrangements, and a large scale, where they
help describe a material as a continuous medium. This enables to formulate
elastic, plastic, fluid behaviours in a common, self-consistent modelling using
continuous mechanics. Experiments, simulations and models can be expressed in
the same language and directly compared. As an example, a companion paper
(Marmottant, Raufaste and Graner, joint paper) provides an application to foam
plasticity.


title: Comment on Experiments Related to the Aharonov-Bohm Phase Shift

abstract:
  Recent experiments undertaken by Caprez, Barwick, and Batelaan should clarify
the connections between classical and quantum theories in connection with the
Aharonov-Bohm phase shift. It is pointed out that resistive aspects for the
solenoid current carriers play a role in the classical but not the quantum
analysis for the phase shift. The observed absence of a classical lag effect
for a macroscopic solenoid does not yet rule out the possibility of a lag
explanation of the observed phase shift for a microscopic solenoid.


title: Ignition latitude and the shape of Type I X-ray bursts

abstract:
  The shape of the lightcurve during the rising phase of Type I X-ray bursts is
determined by many factors including the ignition latitude, the accretion rate,
and the rotation rate of the star. We develop a phenomenological model of the
burst rise process and show that simple measures of the burst morphology can be
robust diagnostics of ignition latitude and burning regime. We apply our
results to the large sample of bursts from the Low Mass X-ray Binary 4U
1636-536, and find evidence for off-equatorial ignition for many of the bursts.
We argue that such behaviour may be associated with the transition from
hydrogen to helium ignition at accretion rates a few percent of Eddington. We
show that this model can also explain variations in the detectability of burst
oscillations, and discuss the implications for other burst sources.


title:
New Global Fit to the Total Photon-Proton Cross-Section sigma L+T and to
  the Structure Function F2

abstract:
  A fit to world data on the photon-proton cross section sigma L+T and the
unpolarised structure function F2 is presented. The 23-parameter ALLM model
based on Reggeon and Pomeron exchange is used. Cross section data were
reconstructed to avoid inconsistencies with respect to R of the published F2
data base. Parameter uncertainties and correlations are obtained.


title:
From Microscales to Macroscales in 3D: Selfconsistent Equation of State
  for Supernova and Neutron Star Models

abstract:
  First results from a fully self-consistent, temperature-dependent equation of
state that spans the whole density range of neutron stars and supernova cores
are presented. The equation of state (EoS) is calculated using a mean-field
Hartree-Fock method in three dimensions (3D). The nuclear interaction is
represented by the phenomenological Skyrme model in this work, but the EoS can
be obtained in our framework for any suitable form of the nucleon-nucleon
effective interaction. The scheme we employ naturally allows effects such as
(i) neutron drip, which results in an external neutron gas, (ii) the variety of
exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii)
the subsequent dissolution of these nuclei into nuclear matter. In this way,
the equation of state is calculated across phase transitions without recourse
to interpolation techniques between density regimes described by different
physical models. EoS tables are calculated in the wide range of densities,
temperature and proton/neutron ratios on the ORNL NCCS XT3, using up to 2000
processors simultaneously.


title:
Universal price impact functions of individual trades in an order-driven
  market

abstract:
  The trade size $\omega$ has direct impact on the price formation of the stock
traded. Econophysical analyses of transaction data for the US and Australian
stock markets have uncovered market-specific scaling laws, where a master curve
of price impact can be obtained in each market when stock capitalization $C$ is
included as an argument in the scaling relation. However, the rationale of
introducing stock capitalization in the scaling is unclear and the anomalous
negative correlation between price change $r$ and trade size $\omega$ for small
trades is unexplained. Here we show that these issues can be addressed by
taking into account the aggressiveness of orders that result in trades together
with a proper normalization technique. Using order book data from the Chinese
market, we show that trades from filled and partially filled limit orders have
very different price impact. The price impact of trades from partially filled
orders is constant when the volume is not too large, while that of filled
orders shows power-law behavior $r\sim \omega^\alpha$ with $\alpha\approx2/3$.
When returns and volumes are normalized by stock-dependent averages,
capitalization-independent scaling laws emerge for both types of trades.
However, no scaling relation in terms of stock capitalization can be
constructed. In addition, the relation $\alpha=\alpha_\omega/\alpha_r$ is
verified, where $\alpha_\omega$ and $\alpha_r$ are the tail exponents of trade
sizes and returns. These observations also enable us to explain the anomalous
negative correlation between $r$ and $\omega$ for small-size trades. We
anticipate that these regularities may hold in other order-driven markets.


title: Phases of Thermal N=2 Quiver Gauge Theories

abstract:
  We consider large N U(N)^M thermal N=2 quiver gauge theories on S^1 x S^3. We
obtain a phase diagram of the theory with R-symmetry chemical potentials,
separating a low-temperature/high-chemical potential region from a
high-temperature/low-chemical potential region. In close analogy with the N=4
SYM case, the free energy is of order O(1) in the low-temperature region and of
order O(N^2 M) in the high-temperature phase. We conclude that the N=2 theory
undergoes a first order Hagedorn phase transition at the curve in the phase
diagram separating these two regions. We observe that in the region of zero
temperature and critical chemical potential the Hilbert space of gauge
invariant operators truncates to smaller subsectors. We compute a l-loop
effective potential with non-zero VEV's for the scalar fields in a sector where
the VEV's are homogeneous and mutually commuting. At low temperatures the
eigenvalues of these VEV's are distributed uniformly over an S^5/Z_M which we
interpret as the emergence of the S^5/Z_M factor of the holographically dual
geometry AdS_5 x S^5/Z_M. Above the Hagedorn transition the eigenvalue
distribution of the Polyakov loop opens a gap, resulting in the collapse of the
joint eigenvalue distribution from S^5/Z_M x S^1 into S^6/Z_M.


title:
First-principles study of the effects of gold adsorption on the Al(001)
  surface properties

abstract:
  In this work, we have studied theoretically the effects of gold adsorption on
the Al(001) surface, using {\it ab initio} pseudo-potential method in the
framework of the density functional theory. Having found the hollow sites at
the Al(001) surface as the most preferred adsorption sites, we have
investigated the effects of the Au adsorption with different coverages
($\Theta$=0.11, 0.25, 0.50, 0.75, 1.00 ML) on the geometry, adsorption energy,
surface dipole moment, and the work-function of the Al(001) surface. The
results show that, even though the work-function of the Al substrate increases
with the Au coverage, the surface dipole moment decreases with the changes in
coverage from $\Theta=0.11$ ML to $\Theta=0.25$ ML. We have explained this
behavior by analyzing the electronic and ionic charge distributions.
Furthermore, by studying the diffusion of Au atoms in to the substrate, we have
shown that at room temperature the diffusion rate of Au atoms in to the
substrate is negligible but, increasing the temperature to about 200$^\circ$ C
the Au atoms significantly diffuse in to the substrate, in agreement with the
experiment.


title: Recent developments of the DDVV Conjecture

abstract:
  In this paper, we give a survey of the recent develpoments of the DDVV
conjecture.


title:
Stochastic solution of nonlinear and nonhomogeneous evolution problems
  by a differential Kolmogorov equation

abstract:
  A large class of physically important nonlinear and nonhomogeneous evolution
problems, characterized by advection-like and diffusion-like processes, can be
usefully studied by a time-differential form of Kolmogorov's solution of the
backward-time Fokker-Planck equation. The differential solution embodies an
integral representation theorem by which any physical or mathematical entity
satisfying a generalized nonhomogeneous advection-diffusion equation can be
calculated incrementally in time. The utility of the approach for tackling
nonlinear problems is illustrated via solution of the noise-free Burgers and
related Kardar-Parisi-Zhang (KPZ) equations where it is shown that the
differential Kolmogorov solution encompasses, and allows derivation of, the
classical Cole-Hopf and KPZ transformations and solutions. A second example,
illustrating application of this approach to nonhomogeneous evolution problems,
derives the Feynman-Kac formula appropriate to a Schrodinger-like equation.


title:
Scalar-tensor black holes coupled to Euler-Heisenberg nonlinear
  electrodynamics

abstract:
  The no-scalar-hair conjecture rules out the existence of asymptotically flat
black holes with a scalar dressing for a large class of theories.
No-scalar-hair theorems have been proved for the cases of neutral black holes
and for charged black holes in the Maxwell electrodynamics. These theorems,
however, do not apply in the case of non-linear electrodynamics. In the present
work numerical solutions describing charged black holes coupled to
Euler-Heisenberg type non-linear electrodynamics in scalar-tensor theories of
gravity with massless scalar field are found. In comparison to the
corresponding solution in General Relativity the presented solution has a
simpler causal structure the reason for which is the presence of the scalar
field. The present class of black holes has a single, non-degenerate horizon,
i.e., its causal structure resembles that of the Schwarzschild black hole.


title:
Main effects of the Earth's rotation on the stationary states of
  ultra-cold neutrons

abstract:
  The relativistic corrections in the Hamiltonian for a particle in a uniformly
rotating frame are discussed. They are shown to be negligible in the case of
ultra-cold neutrons (UCN) in the Earth's gravity. The effect, on the energy
levels of UCN, of the main term due to the Earth's rotation, i.e. the
angular-momentum term, is calculated. The energy shift is found proportional to
the energy level itself.


title:
Human breath analysis via cavity-enhanced optical frequency comb
  spectroscopy

abstract:
  To date, researchers have identified over 1000 different compounds contained
in human breath. These molecules have both endogenous and exogenous origins and
provide information about physiological processes occurring in the body as well
as environment-related ingestion or absorption of contaminants1,2. While the
presence and concentration of many of these molecules are poorly understood,
many 'biomarker' molecules have been correlated to specific diseases and
metabolic processes. Such correlations can result in non-invasive methods of
health screening for a wide variety of medical conditions. In this article we
present human breath analysis using an optical-frequency-comb-based trace
detection system with excellent performance in all criteria: detection
sensitivity, ability to identify and distinguish a large number of biomarkers,
and measurement time. We demonstrate a minimum detectable absorption of 8 x
10-10 cm-1, a spectral resolution of 800 MHz, and 200 nm of spectral coverage
from 1.5 to 1.7 micron where strong and unique molecular fingerprints exist for
many biomarkers. We present a series of breath measurements including stable
isotope ratios of CO2, breath concentrations of CO, and the presence of trace
concentrations of NH3 in high concentrations of H2O.

categories: physics.optics physics.atom-ph physics.chem-ph physics.ins-det


title: Photonic crystal laser-driven accelerator structures

abstract:
  Laser-driven acceleration holds great promise for significantly improving
accelerating gradient. However, scaling the conventional process of
structure-based acceleration in vacuum down to optical wavelengths requires a
substantially different kind of structure. We require an optical waveguide that
(1) is constructed out of dielectric materials, (2) has transverse size on the
order of a wavelength, and (3) supports a mode with speed-of-light phase
velocity in vacuum. Photonic crystals--structures whose electromagnetic
properties are spatially periodic--can meet these requirements.
  We discuss simulated photonic crystal accelerator structures and describe
their properties. We begin with a class of two-dimensional structures which
serves to illustrate the design considerations and trade-offs involved. We then
present a three-dimensional structure, and describe its performance in terms of
accelerating gradient and efficiency. We discuss particle beam dynamics in this
structure, demonstrating a method for keeping a beam confined to the waveguide.
  We also discuss material and fabrication considerations. Since accelerating
gradient is limited by optical damage to the structure, the damage threshold of
the dielectric is a critical parameter. We experimentally measure the damage
threshold of silicon for picosecond pulses in the infrared, and determine that
our structure is capable of sustaining an accelerating gradient of 300 MV/m at
1550 nm. Finally, we discuss possibilities for manufacturing these structures
using common microfabrication techniques.


title: Potential confinement property in the Parabolic Anderson Model

abstract:
  We consider the parabolic Anderson model, the Cauchy problem for the heat
equation with random potential in $Z^d$. We use i.i.d. potentials $\xi: Z^d \to
\R$ in the third universality class, namely the class of almost bounded
potentials, in the classification of van der Hofstad, Konig and Morters
[HKM06]. This class consists of potentials whose logarithmic moment generating
function is regularly varying with parameter $\gamma=1$, but do not belong to
the class of so-called double-exponentially distributed potentials studied by
Gartner and Molchanov (PTRF 1998).
  In [HKM06] the asymptotics of the expected total mass was identified in terms
of a variational problem that is closely connected to the well-known
logarithmic Sobolev inequality and whose solution, unique up to spatial shifts,
is a perfect parabola. In the present paper we show that those potentials whose
shape (after appropriate vertical shifting and spatial rescaling) is away from
that parabola contribute only negligibly to the total mass. The topology used
is the strong $L^1$-topology on compacts for the exponentials of the potential.
In the course of the proof, we show that any sequence of approximate minimisers
of the above variational formula approaches some spatial shift of the
minimiser, the parabola.


title: Mermin inequalities for perfect correlations

abstract:
  Any n-qubit state with n independent perfect correlations is equivalent to a
graph state. We present the optimal Bell inequalities for perfect correlations
and maximal violation for all classes of graph states with n < 7 qubits. Twelve
of them were previously unknown and four give the same violation as the
Greenberger-Horne-Zeilinger state, although the corresponding states are more
resistant to decoherence.


title: Relativistic Aberration for Accelerating Observers

abstract:
  We investigate the effects of the aberration of light for a uniformly
accelerating observer. The observer we consider is initially at rest with
respect to a luminous spherical object--a star, say--and then starts to move
away with constant acceleration. The main results we derive are the following:
(i) The observer always sees an initial increase of the apparent size of the
object; (ii) The apparent size of the object approaches a non-zero value as the
proper time of the observer goes to infinity. (iii) There exists a critical
value of the acceleration such that the apparent size of the object is always
increasing when the acceleration is super-critical. We show that, while (i) is
a purely non-relativistic effect, (ii) and (iii) are effects of the
relativistic aberration of light and are intimately connected with the
Lorentzian geometry of Minkowksi spacetime. Finally, the examples we present
illustrate that, while more or less negligible in everyday life, the three
effects can be significant in the context of space-flight.


title: Effects of fluctuation on alpha-omega dynamo models

abstract:
  We analyse the role of a fluctuating alpha-effect in alpha-omega dynamo
models, and show that there is a mechanism for magnetic field generation, valid
at large scale separation, deriving from the interaction of mean shear and a
fluctuating alpha-effect. It is shown that this effect can act as a dynamo even
in the absence of a mean alpha-effect, and that the timescale for dynamo waves
is strongly affected by the presence of fluctuations.


title:
Monte Carlo study of Bose Laughlin wave function for filling factors
  1/2, 1/4 and 1/6

abstract:
  Strongly correlated two-dimensional electronic systems subject to a
perpendicular magnetic field at lowest Landau level (LLL) filling factors: 1/2,
1/4 and 1/6 are believed to be composite fermion (CF) Fermi liquid phases. Even
though a Bose Laughlin wave function cannot describe these filling factors we
investigate whether such a wave function provides a lower energy bound to the
true CF Fermi liquid energies. By using Monte Carlo simulations in disk
geometry we compute the Bose Laughlin energies and compare them to
corresponding results for the spin-polarized LLL CF Fermi liquid state and
avalable data from literature.We find the unexpected result that, for filling
factors 1/4 and 1/6, the Bose Laughlin ground state energy is practically
identical to the true CF liquid energy while this is not the case at 1/2 where
the Bose Laughlin ground state energy is sizeably lower than the energy of the
CF Fermi liquid state.


title:
A New Study of the Transition to Uniform Nuclear Matter in Neutron Stars
  and Supernovae

abstract:
  A comprehensive microscopic study of the properties of bulk matter at
densities just below nuclear saturation $\rho_s = 2.5 \sim 10^{14}$ g
cm$^{-3}$, zero and finite temperature and high neutron fraction, is outlined,
and preliminary results presented. Such matter is expected to exist in the
inner crust of neutron stars and during the core collapse of massive stars with
$M \gtrsim 8M_{\odot}


title:
Continuous Time Random Walks in periodic systems: fluid limit and
  fractional differential equations on the circle

abstract:
  In this article, the continuous time random walk on the circle is studied. We
derive the corresponding generalized master equation and discuss the effects of
topology, especially important when Levy flights are allowed. Then, we work out
the fluid limit equation, formulated in terms of the periodic version of the
fractional Riemann-Liouville operators, for which we provide explicit
expressions. Finally, we compute the propagator in some simple cases. The
analysis presented herein should be relevant when investigating anomalous
transport phenomena in systems with periodic dimensions.


title: 3D N = 1 SYM Chern-Simons theory on the Lattice

abstract:
  We present a method to implement 3-dimensional N = 1 SUSY Yang-Mills theory
(a theory with two real supercharges containing gauge fields and an adjoint
Majorana fermion) on the lattice, including a way to implement the Chern-Simons
term present in this theory. At nonzero Chern-Simons number our implementation
suffers from a sign problem which will make the numerical effort grow
exponentially with volume. We also show that the theory with vanishing
Chern-Simons number is anomalous; its partition function identically vanishes.


title:
Cumulative hard X-ray spectrum of local AGN: a link to the cosmic X-ray
  background

abstract:
  We determine the cumulative spectral energy distribution (SED) of local AGN
in the 3-300 keV band and compare it with the spectrum of the cosmic X-ray
background (CXB) in order to test the widely accepted paradigm that the CXB is
a superposition of AGN and to place constraints on AGN evolution. We performed
a stacking analysis of the hard X-ray spectra of AGN detected in two recent
all-sky surveys, performed by the IBIS/ISGRI instrument aboard INTEGRAL and by
the PCA instrument aboard RXTE, taking into account the space densities of AGN
with different luminosities and absorption column densities. We derived the
collective SED of local AGN in the 3-300 keV energy band. Those AGN with
luminosities below 10^43.5 erg/s (17-60 keV) provide the main contribution to
the local volume hard X-ray emissivity, at least 5 times more than more
luminous objects. The cumulative spectrum exhibits (although with marginal
significance) a cutoff at energies above 100-200 keV and is consistent with the
CXB spectrum if AGN evolve over cosmic time in such a way that the SED of their
collective high-energy emission has a constant shape and the relative fraction
of obscured AGN remains nearly constant, while the AGN luminosity density
undergoes strong evolution between z~1 and z=0, a scenario broadly consistent
with results from recent deep X-ray surveys. The first direct comparison
between the collective hard X-ray SED of local AGN and the CXB spectrum
demonstrates that the popular concept of the CXB being a superposition of AGN
is generally correct. By repeating this test using improved AGN statistics from
current and future hard X-ray surveys, it should be possible to tighten the
constraints on the cosmic history of black hole growth.


title:
Robust creation of arbitrary-sized Dicke states using a single laser
  pulse

abstract:
  We propose a novel technique for the creation of maximally entangled
symmetric Dicke states in an ion trap using adiabatic passage, which requires
only a pair of chirped pulses from a single laser and is applicable to any
number of ions and excitations. By utilising a particular factorisation of the
Hilbert space for multi-level ladders we show that the problem can be reduced
to `bow-tie' configuration energy-level crossings. This technique is naturally
robust against fluctuations in the laser intensity and the chirp rate. Even
when realistic heating rates are considered, we estimate that the overall
fidelity should remain high (e.g. 98% for a ten-ion Dicke state), which
represents a significant improvement over traditional approaches.


title: Dijet Cross Sections and Parton Densities in Diffractive DIS at HERA

abstract:
  Differential dijet cross sections in diffractive deep-inelastic scattering
are measured with the H1 detector at HERA using an integrated luminosity of
51.5 pb-1. The selected events are of the type ep --> eXY, where the system X
contains at least two jets and is well separated in rapidity from the low mass
proton dissociation system Y. The dijet data are compared with QCD predictions
at next-to-leading order based on diffractive parton distribution functions
previously extracted from measurements of inclusive diffractive deep-inelastic
scattering. The prediction describes the dijet data well at low and
intermediate zpom (the fraction of the momentum of the diffractive exchange
carried by the parton entering the hard interaction) where the gluon density is
well determined from the inclusive diffractive data, supporting QCD
factorisation. A new set of diffractive parton distribution functions is
obtained through a simultaneous fit to the diffractive inclusive and dijet
cross sections. This allows for a precise determination of both the diffractive
quark and gluon distributions in the range 0.05<zpom<0.9. In particular, the
precision on the gluon density at high momentum fractions is improved compared
to previous extractions.


title:
Fictitious Play in 3x3 Games: the transition between periodic and
  chaotic behaviour

abstract:
  In the 60's Shapley provided an example of a two player fictitious game with
periodic behaviour. In this game, player $A$ aims to copy $B$'s behaviour and
player $B$ aims to play one ahead of player $A$. In this paper we generalize
Shapley's example by introducing an external parameter. We show that the
periodic behaviour in Shapley's example at some critical parameter value
disintegrates into unpredictable (chaotic) behaviour, with players dithering a
huge number of times between different strategies. At a further critical
parameter the dynamics becomes periodic again and both players aim to play one
ahead of the other.
  We study the dynamics of a two player continuous time bimatrix fictitious
play with the dynamics of a one-parameter family of $3 \times 3$ games that
includes a well-known example of Shapley's as a special case. In this paper we
adopt a geometric (dynamical systems) approach and study the bifurcations of
simple periodic orbits. Here we concentrate on the periodic behaviour, while in
a sequel we shall describe the chaotic behaviour.


title: Doppler Boosting, Superluminal Motion, and the Kinematics of AGN Jets

abstract:
  We discuss results from a decade long program to study the fine-scale
structure and the kinematics of relativistic AGN jets with the aim of better
understanding the acceleration and collimation of the relativistic plasma
forming AGN jets. From the observed distribution of brightness temperature,
apparent velocity, flux density, time variability, and apparent luminosity, the
intrinsic properties of the jets including Lorentz factor, luminosity,
orientation, and brightness temperature are discussed. Special attention is
given to the jet in M87, which has been studied over a wide range of
wavelengths and which, due to its proximity, is observed with excellent spatial
resolution.
  Most radio jets appear quite linear, but we also observe curved non-linear
jets and non-radial motions. Sometimes, different features in a given jet
appear to follow the same curved path but there is evidence for ballistic
trajectories as well. The data are best fit with a distribution of Lorentz
factors extending up to gamma ~30 and intrinsic luminosity up to ~10^26 W/Hz.
In general, gamma-ray quasars may have somewhat larger Lorentz factors than non
gamma-ray quasars. Initially the observed brightness temperature near the base
of the jet extend up to ~5x10^13 K which is well in excess of the inverse
Compton limit and corresponds to a large excess of particle energy over
magnetic energy. However, more typically, the observed brightness temperatures
are ~2x10^11 K, i.e., closer to equipartition.


title: Optimal strategies in the average consensus problem

abstract:
  We prove that for a set of communicating agents to compute the average of
their initial positions (average consensus problem), the optimal topology of
communication is given by a de Bruijn's graph. Consensus is then reached in a
finitely many steps. A more general family of strategies, constructed by block
Kronecker products, is investigated and compared to Cayley strategies.


title:
Transient and Highly Polarized Double-Peaked H-alpha Emission in the
  Seyfert 2 Nucleus of NGC 2110

abstract:
  We have discovered an extremely broad, double-peaked H-alpha emission line in
the polarized flux spectrum of NGC 2110, establishing that this well-studied
Seyfert 2 galaxy contains a disk-like hidden broad-line region (BLR). Several
properties of NGC 2110 suggest that it is an obscured twin of Arp 102B, the
prototypical double-peaked emission-line active galactic nucleus (AGN). A
comparison between our data and previous spectra of NGC 2110 indicates that the
double-peaked H-alpha feature is transient. The presence of a disk-like BLR in
NGC 2110 has important implications for AGNs: it expands the range of
properties exhibited by Seyfert 2 galaxies, and the fact that the BLR is
obscured by a torus-like structure provides the first evidence that
double-peaked emitters and classical Seyfert nuclei may have the same basic
parsec-scale geometry.


title: On the consistency of coset space dimensional reduction

abstract:
  In this letter we consider higher-dimensional Yang-Mills theories and examine
their consistent coset space dimensional reduction. Utilizing a suitable ansatz
and imposing a simple set of constraints we determine the four-dimensional
gauge theory obtained from the reduction of both the higher-dimensional
Lagrangian and the corresponding equations of motion. The two reductions yield
equivalent results and hence they constitute an example of a consistent
truncation.


title:
Real Zeros and Normal Distribution for statistics on Stirling
  permutations defined by Gessel and Stanley

abstract:
  We study Stirling permutations defined by Gessel and Stanley.
  We prove that their generating function according to the number of descents
has real roots only. We use that fact to prove that the distribution of these
descents, and other, equidistributed statistics on these objects converge to a
normal distribution.


title: The Frobenius Problem in a Free Monoid

abstract:
  The classical Frobenius problem is to compute the largest number g not
representable as a non-negative integer linear combination of non-negative
integers x_1, x_2, ..., x_k, where gcd(x_1, x_2, ..., x_k) = 1. In this paper
we consider generalizations of the Frobenius problem to the noncommutative
setting of a free monoid. Unlike the commutative case, where the bound on g is
quadratic, we are able to show exponential or subexponential behavior for an
analogue of g, depending on the particular measure chosen.


title:
Phase diagram of randomly pinned vortex matter in layered
  superconductors: dependence on the details of the point pinning

abstract:
  We study the thermodynamic and structural properties of the superconducting
vortex system in high temperature layered superconductors, with magnetic field
normal to the layers, in the presence of a small concentration of strong random
point pinning defects via numerical minimization of a model free energy
functional in terms of the time-averaged local density of pancake vortices.
Working at constant magnetic induction and point pinning center concentration,
we find that the equilibrium phase at low temperature ($T$) and small pinning
strength ($s$) is a topologically ordered Bragg glass. As $T$ or $s$ is
increased, the Bragg glass undergoes a first order transition to a disordered
phase which we characterize as a ``vortex slush'' with polycrystalline
structure within the layers and interlayer correlations extending to about
twenty layers. This is in contrast with the pinned vortex liquid phase into
which the Bragg glass was found to melt, using the same methods, in the case of
a large concentration of weak pinning centers: that phase was amorphous with
very little interlayer correlation. The value of the second moment of the
random pinning potential at which the Bragg glass melts for a fixed temperature
is very different in the two systems. These results imply that the effects of
random point pinning can not be described only in terms of the second moment of
the pinning potential, and that some of the unresolved contradictions in the
literature concerning the nature of the low $T$ and high $s$ phase in this
system are likely to arise from differences in the nature of the pinning in
different samples, or from assumptions made about the pinning potential.


title: A Dichotomy Theorem for General Minimum Cost Homomorphism Problem

abstract:
  In the constraint satisfaction problem ($CSP$), the aim is to find an
assignment of values to a set of variables subject to specified constraints. In
the minimum cost homomorphism problem ($MinHom$), one is additionally given
weights $c_{va}$ for every variable $v$ and value $a$, and the aim is to find
an assignment $f$ to the variables that minimizes $\sum_{v} c_{vf(v)}$. Let
$MinHom(\Gamma)$ denote the $MinHom$ problem parameterized by the set of
predicates allowed for constraints. $MinHom(\Gamma)$ is related to many
well-studied combinatorial optimization problems, and concrete applications can
be found in, for instance, defence logistics and machine learning. We show that
$MinHom(\Gamma)$ can be studied by using algebraic methods similar to those
used for CSPs. With the aid of algebraic techniques, we classify the
computational complexity of $MinHom(\Gamma)$ for all choices of $\Gamma$. Our
result settles a general dichotomy conjecture previously resolved only for
certain classes of directed graphs, [Gutin, Hell, Rafiey, Yeo, European J. of
Combinatorics, 2008].


title:
Network formation and relaxation dynamics in a new model for colloidal
  gelation

abstract:
  We investigate the gel formation from the equilibrium sol phase in a simple
model that has the characteristics of (colloidal) gel-forming systems at a
finite temperature. At low volume fraction and low temperatures, particles are
linked by long-living bonds and form an open percolating network. By means of
molecular dynamics simulations, we study the lifetime of bonds and nodes of the
gel network in order to relate these quantities to the complex relaxation
dynamics observed.


abstract:
  We study structures of derivation modules of Coxeter multiarrangements with
quasi-constant multiplicities by using the primitive derivation. As an
application, we show that the characteristic polynomial of a Coxeter
multiarrangement with quasi-constant multiplicity is combinatorially
computable.


title:
Ballistic vs Diffusive Transport in Current-Induced Magnetization
  Switching

abstract:
  We test whether current-induced magnetization switching due to
spin-transfer-torque in ferromagnetic/non-magnetic/ferromagnetic (F/N/F)
trilayers changes significantly when scattering within the N-metal layers is
changed from ballistic to diffusive. Here ballistic corresponds to a ratio r =
lambda/t greater than or equal to 3 for a Cu spacer layer, and diffusive to r =
lambda/t less than or equal to 0.4 for a CuGe alloy spacer layer, where lambda
is the mean-free-path in the N-layer of fixed thickness t = 10 nm. The average
switching currents for the alloy spacer layer are only modestly larger than
those for Cu. The best available model predicts a much greater sensitivity of
the switching currents to diffuse scattering in the spacer layer than we see.


title:
Can Alice and Bob be random: a study on human playing zero knowledge
  protocols

abstract:
  The research described in this abstract was initiated by discussions between
the author and Giovanni Di Crescenzo in Barcelona in early 2004. It was during
Advanced Course on Contemporary Cryptology that Di Crescenzo gave a course on
zero knowledge protocols (ZKP), see [1]. After that course we started to play
with unorthodox ideas for breaking ZKP, especially one based on graph
3-coloring. It was chosen for investigation because it is being considered as a
"benchmark" ZKP, see [2], [3]. At this point we briefly recall such a
protocol's description.


title: Current-induced torques due to compensated antiferromagnets

abstract:
  We analyse the influence of current induced torques on the magnetization
configuration of a ferromagnet in a circuit containing a compensated
antiferromagnet. We argue that these torques are generically non-zero and
support this conclusion with a microscopic NEGF calculation for a circuit
containing antiferromagnetic NiMn and ferromagnetic Co layers. Because of
symmetry dictated differences in the form of the current-induced torque, the
phase diagram which expresses the dependence of ferromagnet configuration on
current and external magnetic field differs qualitatively from its
ferromagnet-only counterpart.


title: Complexity results for CR mappings between spheres

abstract:
  Using elementary number theory, we prove several results about the complexity
of CR mappings between spheres. It is known that CR mappings between spheres,
invariant under finite groups, lead to sharp bounds for degree estimates on
real polynomials constant on a hyperplane. We show here that there are
infinitely many degrees for which the uniqueness of sharp examples fails. The
proof uses a Pell equation and complicated explicit computations. We also show
that the so-called gap phenomenon for proper mappings between balls does not
occur beyond a certain target dimension. This proof uses the solution of the
postage stamp problem.


title: Sakai-Sugimoto model, Tachyon Condensation and Chiral symmetry Breaking

abstract:
  We modify the Sakai-Sugimoto model of chiral symmetry breaking to take into
account the open string tachyon which stretches between the flavour D8-branes
and anti D8-branes. There are several reasons of consistency for doing this:
(i) Even if it might be reasonable to ignore the tachyon in the ultraviolet
where the flavour branes and antibranes are well separated and the tachyon is
small, it is likely to condense and acquire large values in the infrared where
the branes meet. This takes the system far away from the perturbatively stable
minimum of the Sakai-Sugimoto model; (ii) The bifundamental coupling of the
tachyon to fermions of opposite chirality makes it a suitable candidate for the
quark mass and chiral condensate parameters. We show that the modified
Sakai-Sugimoto model with the tachyon present has a classical solution
satisfying all the desired consistency properties. In this solution chiral
symmetry breaking coincides with tachyon condensation. We identify the
parameters corresponding to the quark mass and the chiral condensate and also
briefly discuss the mesonic spectra.


title:
The Repetition Property for Sequences on Tori Generated by Polynomials
  or Skew-Shifts

abstract:
  The repetition property of a sequence in a metric space, a notion introduced
by us in an earlier paper, is of importance in the spectral analysis of ergodic
Schr\"odinger operators. It may be used to exclude eigenvalues for such
operators. In this paper we study the question of when a sequence on a torus
that is generated by a polynomial or a skew-shift has the repetition property.
This provides classes of ergodic Schr\"odinger operators with potentials
generated by skew-shifts on tori that have, contrary to earlier belief, no
eigenvalues.


title: Does Planck mass run on the cosmological horizon scale?

abstract:
  Einstein's theory of general relativity, which contains a universal value of
the Planck mass, has been so far successfully invoked to explain gravitational
dynamics from sub-millimeter scales to the scale of the cosmological horizon.
However, one may envisage that in alternative theories of gravity, the
effective value of the Planck mass (or Newton's constant), which quantifies the
coupling of matter to metric perturbations, can run on the cosmological horizon
scale. In this letter, we study the consequences of a glitch in the Planck mass
from sub-horizon to super-horizon scales. We first give three examples of
models that naturally exhibit this feature, and then show that current
cosmological observations severely constrain this glitch to less than 1.2%.
This is the strongest constraint to date, on natural (i.e. non-fine-tuned)
deviations from Einstein gravity on the cosmological horizon scale.


title: Flux locking a superfluid interferometer

abstract:
  We demonstrate a flux locking technique using injected heat current to
linearize the output of a superfluid helium-4 interferometer. A rotation flux
through the interferometer loop produces a shift in the phase of the superfluid
order parameter. This shift is nullified via negative feedback by a phase-shift
caused by the injected heat current. The feedback signal is then a linear
function of rotation flux.


title: Braneworld dynamics in Einstein-Gauss-Bonnet gravity

abstract:
  We discuss the cosmological evolution of a braneworld in five dimensional
Gauss-Bonnet gravity. Our discussion allows the fifth (bulk) dimension to be
space-like as well as time-like. The resulting equations of motion have the
form of a cubic equation in the (H^2,(\rho+\sigma)^2) plane, where \sigma is
the brane tension and \rho is the matter density. This allows us to conduct a
comprehensive pictorial analysis of cosmological evolution for the Gauss-Bonnet
brane. The many interesting properties of this braneworld include the
possibility of accelerated expansion at late times. For a finite region in
parameter space the accelerated expansion can be phantom-like so that w < -1.
At late times, this branch approaches de Sitter space (w = -1) and avoids the
big-rip singularities usually present in phantom models. For a time-like extra
dimension the Gauss-Bonnet brane can bounce and avoid the initial singularity.


title: How well do we know the Unitarity Triangle? An experimental review

abstract:
  In the past 10 years our knowledge of the parameters rho and eta of the
Cabibbo-Kobayashi-Maskawa matrix has improved substantially. This article
reviews the measurements that contributed to this advance, and discusses their
implication in terms of understanding CP violation in the Standard Model and
beyond.


title: Electron-Electron Interactions in Graphene

abstract:
  We discuss the validity (or not) of the ring-diagram approximation (i.e. RPA)
in the calculation of graphene self-energy in the weak-coupling ($r_s \ll 1$)
limit, showing that RPA is a controlled and valid approximation for
\textit{extrinsic} graphene where the Fermi level is away from the Dirac point.


title: The growth of luminous red galaxies by merging

abstract:
  We study the role of major and minor mergers in the mass growth of luminous
red galaxies. We present small-scale ($0.01<r<8\,\hMpc$) projected
cross-correlation functions of $23043$ luminous early-type galaxies from the
Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy (LRG) sample
($0.16<z<0.30$, $\MMi\approx -22.75\,\mag$) with all their companions in the
SDSS imaging sample, split into color and luminosity subsamples with
$\MMi<-18\,\mag$. We de-project the two-dimensional functions to obtain
three-dimensional real-space LRG--galaxy cross-correlation functions for each
companion subsample. We find that the cross-correlation functions are not
purely power-law and that there is a clear ``one-halo'' to ``two-halo''
transition near $1\,\hMpc$. We convert these results into close pair statistics
and estimate the LRG accretion rate from each companion galaxy subsample using
timescales from dynamical friction arguments for each subsample of the
companions. We find that the accretion onto LRGs is dominated by dry mergers of
galaxies more luminous than $\Lstar$. We integrate the luminosity accretion
rate from mergers over all companion galaxy subsamples and find that LRGs are
growing by $[1.7\pm 0.1]$ percent per $\Gyr$, on average, from merger activity
at redshift $z\sim 0.25$. This rate is almost certainly an over-estimate
because we have assumed that all close pairs are merging as quickly as
dynamical friction allows; nonetheless it is on the low side of the panoply of
measurements in the literature, and lower than any rate predicted from theory.


title: Supersolid Bose-Fermi Mixtures in Optical Lattices

abstract:
  We study a mixture of strongly interacting bosons and spinless fermions with
on-site repulsion in a three-dimensional optical lattice. For this purpose we
develop and apply a generalized DMFT scheme, which is exact in infinite
dimensions and reliably describes the full range from weak to strong coupling.
We restrict ourselves to half filling. For weak Bose-Fermi repulsion a
supersolid forms, in which bosonic superfluidity coexists with charge-density
wave order. For stronger interspecies repulsion the bosons become localized
while the charge density wave order persists. The system is unstable against
phase separation for weak repulsion among the bosons.


title:
Multi-Dimensional Simulations for Early Phase Spectra of Aspherical
  Hypernovae: SN 1998bw and Off-Axis Hypernovae

abstract:
  Early phase optical spectra of aspherical jet-like supernovae (SNe) are
presented. We focus on energetic core-collapse SNe, or hypernovae. Based on
hydrodynamic and nucleosynthetic models, radiative transfer in SN atmosphere is
solved with a multi-dimensional Monte-Carlo radiative transfer code, SAMURAI.
Since the luminosity is boosted in the jet direction, the temperature there is
higher than in the equatorial plane by ~ 2,000 K. This causes anisotropic
ionization in the ejecta. Emergent spectra are different depending on viewing
angle, reflecting both aspherical abundance distribution and anisotropic
ionization. Spectra computed with an aspherical explosion model with kinetic
energy 20 x 10^{51} ergs are compatible with those of the Type Ic SN 1998bw if
~ 10-20% of the synthesized metals are mixed out to higher velocities. The
simulations enable us to predict the properties of off-axis hypernovae. Even if
an aspherical hypernova explosion is observed from the side, it should show
hypernova-like spectra but with some differences in the line velocity, the
width of the Fe absorptions and the strength of the Na I line.


title:
Large-Scale Gravitational Instability and Star Formation in the Large
  Magellanic Cloud

abstract:
  Large-scale star formation in disk galaxies is hypothesized to be driven by
global gravitational instability. The observed gas surface density is commonly
used to compute the strength of gravitational instability, but according to
this criterion star formation often appears to occur in gravitationally stable
regions. One possible reason is that the stellar contribution to the
instability has been neglected. We have examined the gravitational instability
of the Large Magellanic Cloud (LMC) considering the gas alone, and considering
the combination of collisional gas and collisionless stars. We compare the
gravitationally unstable regions with the on-going star formation revealed by
Spitzer observations of young stellar objects. Although only 62% of the massive
young stellar object candidates are in regions where the gas alone is unstable,
some 85% lie in regions unstable due to the combination of gas and stars. The
combined stability analysis better describes where star formation occurs. In
agreement with other observations and numerical models, a small fraction of the
star formation occurs in regions with gravitational stability parameter Q > 1.
We further measure the dependence of the star formation timescale on the
strength of gravitational instability, and quantitatively compare it to the
exponential dependence expected from numerical simulations.


title:
About the Power to Enforce and Prevent Consensus by Manipulating
  Communication Rules

abstract:
  We explore the possibilities of enforcing and preventing consensus in
continuous opinion dynamics that result from modifications in the communication
rules. We refer to the model of Weisbuch and Deffuant, where $n$ agents adjust
their continuous opinions as a result of random pairwise encounters whenever
their opinions differ not more than a given bound of confidence $\eps$. A high
$\eps$ leads to consensus, while a lower $\eps$ leads to a fragmentation into
several opinion clusters. We drop the random encounter assumption and ask: How
small may $\eps$ be such that consensus is still possible with a certain
communication plan for the entire group? Mathematical analysis shows that
$\eps$ may be significantly smaller than in the random pairwise case. On the
other hand we ask: How large may $\eps$ be such that preventing consensus is
still possible? In answering this question we prove Fortunato's simulation
result that consensus cannot be prevented for $\eps>0.5$ for large groups. %
Next we consider opinion dynamics under different individual strategies and
examine their power to increase the chances of consensus. One result is that
balancing agents increase chances of consensus, especially if the agents are
cautious in adapting their opinions. However, curious agents increase chances
of consensus only if those agents are not cautious in adapting their opinions.


title: Surface modes and breathers in finite arrays of nonlinear waveguides

abstract:
  We present the complete set of symmetric and antisymmetric (edge and corner)
surface modes in finite one-- and two--dimensional arrays of waveguides. We
provide classification of the modes based on the anti-continuum limit, study
their stability and bifurcations, and discuss relation between surface and bulk
modes. We put forward existence of surface breathers, which represent
two-frequency modes localized about the array edges.


title: Transversity quark distributions in a covariant quark-diquark model

abstract:
  Transversity quark light-cone momentum distributions are calculated for the
nucleon. We utilize a modified Nambu--Jona-Lasinio model in which confinement
is simulated by eliminating unphysical thresholds for nucleon decay into
quarks. The nucleon bound state is obtained by solving the relativistic Faddeev
equation in the quark-diquark approximation, where both scalar and axial-vector
diquark channels are included. Particular attention is paid to comparing our
results with the recent experimental extraction of the transversity
distributions by Anselmino et al. We also compare our transversity results with
earlier spin-independent and helicity quark distributions calculated in the
same approach.


title: A new integrable generalization of the Korteweg - de Vries equation

abstract:
  A new integrable sixth-order nonlinear wave equation is discovered by means
of the Painleve analysis, which is equivalent to the Korteweg - de Vries
equation with a source. A Lax representation and a Backlund self-transformation
are found of the new equation, and its travelling wave solutions and
generalized symmetries are studied.


title: Electroweak Symmetry Breaking in the E6SSM

abstract:
  The Exceptional Supersymmetric Standard Model (E6SSM) is an E6 inspired model
with an extra gauged U(1) symmetry, which solves the mu-problem in a similar
way to the NMSSM but without the accompanying problems of singlet tadpoles or
domain walls. It predicts new exotic particles at the TeV scale. We investigate
the Renormalisation Group Evolution of the model and test electroweak symmetry
breaking for a selection of interesting scenarios with non-universal Higgs
masses at the GUT scale. We present a detailed particle spectrum that could be
observed at the LHC.


title: On the Khovanov and knot Floer homologies of quasi-alternating links

abstract:
  Quasi-alternating links are a natural generalization of alternating links. In
this paper, we show that quasi-alternating links are "homologically thin" for
both Khovanov homology and knot Floer homology. In particular, their bigraded
homology groups are determined by the signature of the link, together with the
Euler characteristic of the respective homology (i.e. the Jones or the
Alexander polynomial). The proofs use the exact triangles relating the homology
of a link with the homologies of its two resolutions at a crossing.


title: Topological estimation of percolation thresholds

abstract:
  Global physical properties of random media change qualitatively at a
percolation threshold, where isolated clusters merge to form one infinite
connected component. The precise knowledge of percolation thresholds is thus of
paramount importance. For two dimensional lattice graphs, we use the universal
scaling form of the cluster size distributions to derive a relation between the
mean Euler characteristic of the critical percolation patterns and the
threshold density $p_c$. From this relation, we deduce a simple rule to
estimate $p_c$, which is remarkably accurate. We present some evidence that
similar relations might hold for continuum percolation and percolation in
higher dimensions.


title: Supplementary material: Topological estimation of percolation thresholds

abstract:
  This is supplementary material for the article arxiv:0708.3250. We provide an
alternative introduction of the mean Euler Characteristic, additional examples
and the percolation thresholds for 2-uniform lattices.


title:
Generalized Relativistic Chapman-Enskog Solution of the Boltzmann
  Equation

abstract:
  The Chapman-Enskog method of solution of the relativistic Boltzmann equation
is generalized in order to admit a time-derivative term associated to a
thermodynamic force in its first order solution. Both existence and uniqueness
of such a solution are proved based on the standard theory of integral
equations. The mathematical implications of the generalization here introduced
are thoroughly discussed regarding the nature of heat as chaotic energy
transfer in the context of relativity theory.


title:
Complex X-ray morphology of Abell 3128: A distant cluster behind a
  disturbed cluster

abstract:
  We present here the results of a detailed study of the X-ray properties of
the cluster of galaxies Abell 3128 (z=0.06), based on the analysis of deep (100
ks) XMM-Newton data. The most obvious feature of the X-ray morphology of A3128
is the presence of two X-ray peaks separated by ~12'. By detecting the
redshifted Fe K line, we find that the Northeast (NE) X-ray peak observed
toward A3128 is a distant luminous cluster of galaxies at redshift z=0.44. Our
subsequent optical spectroscopic observation of a distant radio bright galaxy
in the centre of the NE X-ray peak with the Magellan telescope also revealed a
redshift of z=0.44, confirming the association of the galaxy with the cluster
seen in X-rays. We detect a gravitational arc around the galaxy. The properties
of this galaxy indicate that it is the cD galaxy of the cluster in the
background. The properties of the Southwest X-ray peak suggest that it is the
core of a group merging with A3128 along our line of sight. Based on 2D maps of
thermodynamic properties of the intra-cluster medium determined after
subtracting a model for the background cluster, we conclude that an enhanced
surface brightness region at a distance of ~2.8' from the centre of the galaxy
distribution is the centre of the gravitational potential of the cluster A3128.
The unrelaxed nature of A3128 can be attributed to its location in the high
density environment of the Horologium-Reticulum supercluster.


title: Applications of Wallis Theorem

abstract:
  In this paper we present theorems and applications of Wallis theorem related
to trigonometric integrals.


title: New H2 Jets in Monoceros R2

abstract:
  We are presenting a wide-field image of the Mon R2 star forming region
obtained with WFCAM on UKIRT in the 2.12 micron filter centered on the H2 1--0
S(1) emission line. We report the discovery of 15 new H2 jets in Mon R2 and two
in L 1646 and confirm most of these discoveries using archival Spitzer IRAC 4.5
and 8.0 micron images. We find that many of these protostellar jets are found
in projection against the outflow cavities of the huge CO outflow in Mon R2,
suggesting that the jets may be associated with an episode of star formation in
Mon R2 triggered by this large, but now fossil, outflow. We also study the
spatial distribution of small, localized reflection nebulae and find that these
are distributed in the same way as photometrically identified Class I sources.


title: The width difference of rho vector mesons

abstract:
  We compute the difference in decay widths of charged and neutral \rho(770)
vector mesons. The isospin breaking arising from mass differences of neutral
and charged \pi and \rho mesons, radiative corrections to \rho -> \pi\pi, and
the \rho -> \pi\pi\gamma decays are taken into account. It is found that the
width difference \Delta \Gamma_rho is very sensitive ot the isospin breaking in
the $\rho$ meson mass \Delta m_\rho. This result can be useful to test the
correlations observed between the values of these parameters extracted from
experimental data.


title: Tong's spectrum for Rosen continued fractions

abstract:
  The Rosen fractions are an infinite set of continued fraction algorithms,
each giving expansions of real numbers in terms of certain algebraic integers.
For each, we give a best possible upper bound for the minimum in appropriate
consecutive blocks of approximation coefficients (in the sense of Diophantine
approximation by continued fraction convergents). We also obtain metrical
results for large blocks of ``bad'' approximations.


title:
The XMM Cluster Survey: The Dynamical State of XMMXCS J2215.9-1738 at
  z=1.457

abstract:
  We present new spectroscopic observations of the most distant X-ray selected
galaxy cluster currently known, XMMXCS J2215.9-1738 at z=1.457, obtained with
the DEIMOS instrument at the W. M. Keck Observatory, and the FORS2 instrument
on the ESO Very Large Telescope. Within the cluster virial radius, as estimated
from the cluster X-ray properties, we increase the number of known
spectroscopic cluster members to 17 objects, and calculate the line of sight
velocity dispersion of the cluster to be 580+/-140 km/s. We find mild evidence
that the velocity distribution of galaxies within the virial radius deviates
from a single Gaussian. We show that the properties of J2215.9-1738 are
inconsistent with self-similar evolution of local X-ray scaling relations,
finding that the cluster is underluminous given its X-ray temperature, and that
the intracluster medium contains ~2-3 times the kinetic energy per unit mass of
the cluster galaxies. These results can perhaps be explained if the cluster is
observed in the aftermath of an off-axis merger. Alternatively, heating of the
intracluster medium through supernovae and/or Active Galactic Nuclei activity,
as is required to explain the observed slope of the local X-ray
luminosity-temperature relation, may be responsible.


title: Fast evaluation of union-intersection expressions

abstract:
  We show how to represent sets in a linear space data structure such that
expressions involving unions and intersections of sets can be computed in a
worst-case efficient way. This problem has applications in e.g. information
retrieval and database systems. We mainly consider the RAM model of
computation, and sets of machine words, but also state our results in the I/O
model. On a RAM with word size $w$, a special case of our result is that the
intersection of $m$ (preprocessed) sets, containing $n$ elements in total, can
be computed in expected time $O(n (\log w)^2 / w + km)$, where $k$ is the
number of elements in the intersection. If the first of the two terms
dominates, this is a factor $w^{1-o(1)}$ faster than the standard solution of
merging sorted lists. We show a cell probe lower bound of time $\Omega(n/(w m
\log m)+ (1-\tfrac{\log k}{w}) k)$, meaning that our upper bound is nearly
optimal for small $m$. Our algorithm uses a novel combination of approximate
set representations and word-level parallelism.


title:
Asymptotically Optimal Importance Sampling for Jackson Networks with a
  Tree Topology

abstract:
  Importance sampling (IS) is a variance reduction method for simulating rare
events. A recent paper by Dupuis, Wang and Sezer (Ann. App. Probab. 17(4):1306-
1346, 2007) exploits connections between IS and stochastic games and optimal
control problems to show how to design and analyze simple and efficient IS
algorithms for various overflow events for tandem Jackson networks. The present
paper uses the same approach to build asymptotically optimal IS schemes for
stable open Jackson networks with a tree topology. Customers arrive at the
single root of the tree. The rare overflow event we consider is the following:
given that initially the network is empty, the system experiences a buffer
overflow before returning to the empty state. Two types of buffer structures
are considered: 1) A single system-wide buffer of size $n$ shared by all nodes,
2) each node $i$ has its own buffer of size $\beta_i n$, $\beta_i \in (0,1)$.


title: Complex Structures on Principal Bundles

abstract:
  Holomorphic principal G-bundles over a complex manifold M can be studied
using non-abelian cohomology groups H^1(M,G). On the other hand, if M=\Sigma is
a closed Riemann surface, there is a correspondence between holomorphic
principal G-bundles over \Sigma and coadjoint orbits in the dual of a central
extension of the Lie algebra C^\infty(\Sigma, \g). We review these results and
provide the details of an integrability condition for almost complex structures
on smoothly trivial bundles. This article is a shortened version of the
author's Diplom thesis.


title: Exciton-Plasmon Coupling in Carbon Nanotubes

abstract:
  We study theoretically the interactions of excitonic states with surface
electromagnetic modes of small-diameter (~1 nm) semiconducting single-walled
carbon nanotubes. We show that these interactions can result in strong
exciton-surface-plasmon coupling. The exciton absorption lineshapes exhibit the
line (Rabi) splitting $~0.1-0.3$ eV as the exciton energy is tuned to the
nearest interband surface plasmon resonance of the nanotube. We expect this
effect to open a path to new optoelectronic device applications of
semiconducting carbon nanotubes.


title: $G$-stable pieces and Lusztig's dimension estimates

abstract:
  We use $G$-stable pieces to construct some equidimensional varieties and as a
consequence, obtain Lusztig's dimension estimates \cite[section 4]{L2}. This is
a generalization of \cite{HL}.


title: Fields and Filaments in the Core of the Centaurus Cluster

abstract:
  We present high resolution images of the Faraday Rotation Measure (RM)
structure of the radio galaxy PKS 1246-410, at the center of the Centaurus
cluster. Comparison with Halpha-line and soft X-ray emission reveals a
correspondence between the line-emitting gas, the soft X-ray emitting gas,
regions with an excess in the RM images, and signs of depolarization. Magnetic
field strengths of 25 microG, organized on scales of ~1 kpc, and intermixed
with gas at a temperature of 5 x 10^6 K with a density of ~0.1 cm^-3 can
reproduce the observed RM excess, the depolarization, and the observed X-ray
surface brightness. This hot gas may be in pressure equilibrium with the
optical line-emitting gas, but the magnetic field strength of 25 microG
associated with the hot gas provides only 10% of the thermal pressure and is
therefore insufficient to account for the stability of the line-emitting
filaments.


title:
Ground and excited-state fermions in a 1D double-well, exact and
  time-dependent density-functional solutions

abstract:
  Two of the most popular quantum mechanical models of interacting fermions are
compared to each other and to potentially exact solutions for a pair of
contact-interacting fermions trapped in a 1D double-well potential, a model of
atoms in a quasi-1D optical lattice or electrons of a Hydrogen molecule in a
strong magnetic field. An exact few-body Hamiltonian is solved numerically in
momentum space yielding a highly-correlated eigenspectrum. Additionally,
approximate ground-state energies are obtained using both density functional
theory (DFT) functional and 2-site Hubbard models. A 1D adiabatic LDA kernel is
constructed for use in time-dependent density functional theory (TDDFT), and
the resulting excited-state spectrum is compared to the exact and Hubbard
results. DFT is shown to give accurate results for wells with small separations
but fails to describe localization of opposite spin fermions to different
sites. A locally cognizant (LC) density functional based on an effective local
fermion number would provide a solution to this problem, and an approximate
treatment presented here compares favorably with the exact and Hubbard results.
The TDDFT excited-state spectrum is accurate in the small parameter regime with
non-adiabatic effects accounting for any deviations. As expected, the
ground-state Hubbard model outperforms DFT at large separations but breaks down
at intermediate separations due to improper scaling to the united-atom limit.
At strong coupling, both Hubbard and TDDFT methods fail to capture the
appropriate energetics.


title: Convergence of freely decomposable Kleinian groups

abstract:
  We consider a compact orientable hyperbolic 3-manifold with a compressible
boundary. Suppose that we are given a sequence of geometrically finite
hyperbolic metrics whose conformal boundary structures at infinity diverge to a
projective lamination. We prove that if this limit projective lamination is
doubly incompressible, then the sequence has compact closure in the deformation
space. As a consequence we generalise Thurston's double limit theorem and solve
his conjecture on convergence of function groups affirmatively.


title:
The Friedel-Anderson and Kondo Impurity Problem for Arbitrary s-Band
  Density of States and Exchange Interaction

abstract:
  In his renormalization paper of the Kondo effect Wilson replaced the full
band of s-electrons by a small number of ''Wilson states''. He started from a
rather artificial symmetric band with constant density of states and constant
interaction with the impurity. It is shown in the present paper that with a
minor modification the Wilson states are optimally suited to treat the
interaction of an impurity with an arbitrary s-band. Each Wilson state
represents electrons of a whole energy range. It carries the interaction of all
these electrons with the impurity. All the other electron states in this energy
range have zero interaction with the impurity and are neglected in the
calculation. The resulting error is minor. As an example the singlet-triplet
excitation energy of a Kondo impurity is numerically calculated for a
tight-binding band with a strongly energy dependent density of states.


title: Ac-cotunneling through an interacting quantum dot under a magnetic field

abstract:
  We analyze inelastic cotunneling through an interacting quantum dot subject
to an ambient magnetic field in the weak tunneling regime under a non-adiabatic
time-dependent bias-voltage. Our results clearly exhibit photon-assisted
satellites and an overall suppression of differential conductance with
increasing driving amplitude, which is consistent with experiments. We also
predict a zero-anomaly in differential conductance under an appropriate driving
frequency.


title:
Resonant electromagnetic emission from intrinsic Josephson-junction
  stacks with laterally modulated Josephson critical current

abstract:
  Intrinsic Josephson-junction stacks realized in mesas fabricated out of
high-temperature superconductors may be used as sources of coherent
electromagnetic radiation in the terahertz range. The major challenge is to
synchronize Josephson oscillations in all junctions in the stack to get
significant radiation out of the crystal edge parallel to the c axis. We
suggest a simple way to solve this problem via artificially prepared lateral
modulation of the Josephson critical current identical in all junctions. In
such a stack phase oscillations excite the in-phase Fiske mode when the
Josephson frequency matches the Fiske-resonance frequency which is set by the
stack lateral size. The powerful almost standing electromagnetic wave is
excited inside the crystal in the resonance. This wave is homogeneous across
the layers meaning that the oscillations are synchronized in all junctions in
the stack. We evaluate behavior of the I-V characteristics and radiated power
near the resonance for arbitrary modulation and find exact solutions for
several special cases corresponding to symmetric and asymmetric modulations of
the critical current.


title:
Green's matrices of second order elliptic systems with measurable
  coefficients in two dimensional domains

abstract:
  We study Green's matrices for divergence form, second order strongly elliptic
systems with bounded measurable coefficients in two dimensional domains. We
establish existence, uniqueness, and pointwise estimates of the Green's
matrices.


title: Simulation of Spread and Control of Lesions in Brain

abstract:
  A simulation model for the spread and control of lesions in the brain is
constructed using a planar network (graph) representation for the Central
Nervous System (CNS). The model is inspired by the lesion structures observed
in the case of Multiple Sclerosis (MS), a chronic disease of the CNS. The
initial lesion site is at the center of a unit square and spreads outwards
based on the success rate in damaging edges (axons) of the network. The damaged
edges send out alarm signals which, at appropriate intensity levels, generate
programmed cell death. Depending on the extent and timing of the programmed
cell death, the lesion may get controlled or aggravated akin to the control of
wild fires by burning of peripheral vegetation. The parameter phase space of
the model shows smooth transition from uncontrolled situation to controlled
situation. The simulations show that the model is capable of generating a wide
variety of lesion growth and arrest scenarios.


title: Search for Lepton Flavor Violating tau Decays into Three Leptons

abstract:
  We search for lepton-flavor-violating tau decays into three leptons (electron
or muon) using 535 fb^{-1} of data collected with the Belle detector at the
KEKB asymmetric-energy e+e- collider. No evidence for these decays is observed
and we set 90% confidence level upper limits on the branching fractions between
2.0x10^{-8} and 4.1x10^{-8}. These results improve the best previously
published upper limits by factors from 4.9 to 7.0.


title:
Path to finding the critical thickness for memory in thin ferroelectric
  films

abstract:
  The finite screening length by real metallic electrodes, albeit very small
(<1A), results in finite depolarizing field that tends to split the film into
domains. In very thin ferroelectric films the domain structure reduces to
sinusoidal distribution of polarization considered first in the 1980s. We
discuss the phase transition between this structure and a single domain state
and show that it is first order, if it exists at all. The alternative
possibility is that the single domain state at zero bias voltage would be
metastable for all temperatures in most systems. This scenario defines a path
towards solution to a problem of finding parameters of a system that can
sustain the ferroelectric memory over a desired period of time.


title: Analytic Constructions of General n-Qubit Controlled Gates

abstract:
  In this Letter, we present two analytic expressions that most generally
simulate $n$-qubit controlled-$U$ gates with standard one-qubit gates and CNOT
gates using exponential and polynomial complexity respectively. Explicit
circuits and general expressions of decomposition are derived. The exact
numbers of basic operations in these two schemes are given using gate counting
technique.


title:
XMM observation of 1RXS J180431.1-273932: a new M-type X-ray binary with
  a 494 s-pulse period neutron star?

abstract:
  Low-mass X-ray binaries are binary systems composed of a compact object and a
low-mass star. Recently, a new class of these systems, known as symbiotic
$X$-ray binaries (with a neutron star with a M-type giant companion), has been
discovered. Here, we present long-duration ${\it XMM}$ observations of the
source 1RXS J180431.1-273932. Temporal and spectral analysis of the source was
performed along with a search for an optical counterpart. We used a
Lomb-Scargle periodogram analysis for the period search and evaluated the
confidence level using Monte-Carlo simulations. The source is characterized by
regular pulses so that it is most likely a neutron star. A modulation of
$494.1\pm0.2$ s (3$\sigma$ error) was found with a confidence level of $>$99%.
Evidence of variability is also present, since the data show a rate of change
in the signal of $\sim -7.7\times 10^{-4}$ counts s$^{-1}$ hr$^{-1}$. A longer
observation will be necessary in order to determine if the source shows any
periodic behavior. The spectrum can be described by a power law with photon
index $\Gamma\sim 1$ and a Gaussian line at 6.6 keV. The X-ray flux in the
0.2--10 keV energy band is $5.4\times 10^{-12}$ erg s$^{-1}$ cm$^{-2}$. The
identification of an optical counterpart (possibly an M6III red-giant star with
an apparent visual magnitude of $\simeq 17.6$) allows a conservative distance
of $\sim 10$ kpc to be estimated. Other possibilities are also discussed. Once
the distance was estimated, we got an $X$-ray luminosity of $L_X\ut<6\times
10^{34}$ erg s$^{-1}$, which is consistent with the typical $X$-ray luminosity
of a symbiotic LMXB system.


title: Search for lepton flavor violating $\tau \to \ell V^0$ decays at Belle

abstract:
  We have searched for neutrinoless $\tau$ lepton decays into $\ell$ and $V^0$,
where $\ell$ stands for an electron or muon, and $V^0$ for a vector meson
($\phi$, $\omega$, $K^{*0}$ or $\bar{K}^{*0}$), using 543 fb$^{-1}$ of data
collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$
collider. No excess of signal events over the expected background is observed,
and we set upper limits on the branching fractions in the range $(0.7 - 1.8)
\times 10^{-7}$ at the 90% confidence level. These upper limits include the
first results for $\ell \omega$ as well as new limits that are $3.6 - 9.6$
times more restrictive than our previous results for $\ell \phi$, $\ell K^{*0}$
and $\ell \bar{K}^{*0}$.


title: Hadron-quark mixed phase in hyperon stars

abstract:
  We analyze the different possibilities for the hadron-quark phase transition
occurring in beta-stable matter including hyperons in neutron stars. We use a
Brueckner-Hartree-Fock approach including hyperons for the hadronic equation of
state and a generalized MIT bag model for the quark part. We then point out in
detail the differences between Maxwell and Gibbs phase transition constructions
including the effects of surface tension and electromagnetic screening. We find
only a small influence on the maximum neutron star mass, whereas the radius of
the star and in particular its internal structure are more affected.


title: A Review of Procedure to Evolve Quantum Procedures

abstract:
  There exist quantum algorithms that are more efficient than their classical
counterparts; such algorithms were invented by Shor in 1994 and then Grover in
1996. A lack of invention since Grover's algorithm has been commonly attributed
to the non-intuitive nature of quantum algorithms to the classically trained
person. Thus, the idea of using computers to automatically generate quantum
algorithms based on an evolutionary model emerged. A limitation of this
approach is that quantum computers do not yet exist and quantum simulation on a
classical machine has an exponential order overhead. Nevertheless, early
research into evolving quantum algorithms has shown promise.
  This paper provides an introduction into quantum and evolutionary algorithms
for the computer scientist not familiar with these fields. The exciting field
of using evolutionary algorithms to evolve quantum algorithms is then reviewed.


title:
Which weakly ramified group actions admit a universal formal
  deformation?

abstract:
  Consider a formal (mixed-characteristic) deformation functor D of a
representation of a finite group G as automorphisms of a power series ring
k[[t]] over a perfect field k of positive characteristic. Assume that the
action of G is weakly ramified, i.e., the second ramification group is trivial.
Examples of such representations are provided by a group action on an ordinary
curve: the action of a ramification group on the completed local ring of any
point on such a curve is weakly ramified.
  We prove that the only such D that are not pro-representable occur if k has
characteristic two and G is of order two or isomorphic to a Klein group.
Furthermore, we show that only the first of those has a non-pro-representable
equicharacteristic deformation functor.


title: Bulk viscosity and deflationary universes

abstract:
  We analyze the conditions that make possible the description of entropy
generation in the new inflationary model by means of a nearequilibrium process.
We show that there are situations in which the bulk viscosity cannot describe
particle production during the coherent field oscillations phase.


title: Chiral violations from one-loop domain wall fermions

abstract:
  We present results from lattice perturbation theory for the residual mass and
other matrix elements measuring the breaking of chiral symmetry in domain-wall
fermions. We have used the exact propagators corresponding to a finite number
of points in the fifth dimensions, and results were obtained for several
choices of the domain-wall parameters.


title: Modeling Crowd Turbulence by Many-Particle Simulations

abstract:
  A recent study [D. Helbing, A. Johansson and H. Z. Al-Abideen, {\it Phys.
Rev. E} 75, 046109 (2007)] has revealed a "turbulent" state of pedestrian
flows, which is characterized by sudden displacements and causes the falling
and trampling of people. However, turbulent crowd motion is not reproduced well
by current many-particle models due to their insufficient representation of the
local interactions in areas of extreme densities. In this contribution, we
extend the repulsive force term of the social force model to reproduce crowd
turbulence. We perform numerical simulations of pedestrians moving through a
bottleneck area with this new model. The transitions from laminar to
stop-and-go and turbulent flows are observed. The empirical features
characterizing crowd turbulence, such as the structure function and the
probability density function of velocity increments are reproduced well, i.e.
they are well compatible with an analysis of video data during the annual
Muslim pilgrimage.


title: Sigma Model Q-balls and Q-Stars

abstract:
  A new kind of Q-balls is found: Q-balls in a non-linear sigma model. Their
main properties are presented together with those of their self-gravitating
generalization, sigma model Q-stars. A simple special limit of solutions which
are bound by gravity alone (``sigma stars'') is also discussed briefly. The
analysis is based on calculating the mass, global U(1) charge and binding
energy for families of solutions parameterized by the central value of the
scalar field. Two kinds (differing by the potential term) of the new sigma
model Q-balls and Q-stars are analyzed. They are found to share some
characteristics while differing in other respects like their properties for
weak central scalar fields which depend strongly on the form of the potential
term. They are also compared with their ``ordinary'' counterparts and although
similar in some respects, significant differences are found like the existence
of an upper bound on the central scalar field. The sigma model Q-stars also
contain non-solitonic solutions whose relation with sigma star solutions is
discussed.


title: Interacting holographic dark energy in the scalar-Gauss-Bonnet gravity

abstract:
  In this paper we study cosmological application of interacting holographic
dark energy density in the scalar-Gauss-Bonnet framework. We employ the
interacting holographic model of dark energy to obtain the equation of state
for the interacting holographic energy density in spatially flat universe. Our
calculation show, taking $\Omega_{\Lambda}=0.73$ for the present time, it is
possible to have $w_{\rm \Lambda}^{eff}$ crossing -1. This implies that one can
generate phantom-like equation of state from the interacting holographic dark
energy model in flat universe in the scalar-Gauss-Bonnet cosmology framework.
Then we reconstruct the potential of the scalar field.


title: Do $c\bar c n\bar n$ bound states exist?

abstract:
  The four--quark system $c\bar c n\bar n$ is studied in the framework of the
constituent quark model. Using different types of quark-quark potentials, we
solve the four--body Schr\"odinger equation by means of the hyperspherical
harmonic formalism. Exploring the low laying $J^{PC}$ states for different
isospin configurations no four-quark bound states have been found. Of
particular interest is the possible four-quark structure of the X(3872). We
rule out the possibility that this particle is a compact tetraquark system,
unless additional correlations, either in the form of diquarks or at the level
of the interacting potential, not considered in simple quark models do
contribute.


title: Experiments with a Positivity Preserving Operator

abstract:
  We consider some multivariate rational functions which have (or are
conjectured to have) only positive coefficients in their series expansion. We
consider an operator that preserves positivity of series coefficients, and
apply the inverse of this operator to the rational functions. We obtain new
rational functions which seem to have only positive coefficients, whose
positivity would imply positivity of the original series, and which, in a
certain sense, cannot be improved any further.


title: Combinatorial Bethe ansatz and generalized periodic box-ball system

abstract:
  We reformulate the Kerov-Kirillov-Reshetikhin (KKR) map in the combinatorial
Bethe ansatz from paths to rigged configurations by introducing local energy
distribution in crystal base theory. Combined with an earlier result on the
inverse map, it completes the crystal interpretation of the KKR bijection for
U_q(\hat{sl}_2). As an application, we solve an integrable cellular automaton,
a higher spin generalization of the periodic box-ball system, by an inverse
scattering method and obtain the solution of the initial value problem in terms
of the ultradiscrete Riemann theta function.


title: The probability of inflation in Loop Quantum Cosmology

abstract:
  The probability of there being sufficient inflation to solve the fine-tuning
associated with the horizon and flatness problems has recently been shown to be
exponentially small, within the context of classical general relativity. Here
this result is extended by considering loop quantum gravity effects, that are
significant at small scales. In addition to accounting for high-energy
departures from classicality, it is shown that, in contrast to the classical
case, the loop quantum cosmological probability measure is naturally finite, at
least in some well defined region. It is also shown that these loop quantum
gravity corrections can overcome the classical suppression of the probability
only for extremely unnatural choices of ambiguity parameters, implying that
single field, slow-roll inflation is exponentially unlikely.


title:
Optimal stability estimate of the inverse boundary value problem by
  partial measurements

abstract:
  In this work we establish log-type stability estimates for the inverse
potential and conductivity problems with partial Dirichlet-to-Neumann map,
where the Dirichlet data is homogeneous on the inaccessible part. This result,
to some extent, improves our former result on the partial data problem in which
log-log-type estimates were derived.


title:
The Centrality Dependence of Strange Baryon and Meson Production in
  Cu+Cu and Au+Au sqrt(s_NN) = 200 GeV collisions

abstract:
  Transverse momentum spectra of Lambda and K0Short particles are presented for
Cu+Cu sqrt(s_NN) = 200 GeV collisions observed at STAR, and compared to Au+Au
measurements at the same energy. For both systems, a number of observables are
shown to increase at mid-rapidity (|y| < 0.5) with increasing centrality. These
are the integrated Lambda and K0Short yields, the integrated Lambda and K0Short
yields per participating nucleon, and mid-pT (1 GeV/c -> 4.5 GeV/c)
Lambda/KK0Short ratios. The RCP ratio is found to be higher for the Lambda
yields at mid-pT compared to the K0Short yields for both the Cu+Cu and Au+Au
data. In contrast, when similar numbers of participating nucleons are
considered for the Cu+Cu and Au+Au data, an indication of increased bulk
strangeness production and a higher mid-pT (1 -> 4.5 GeV/c) Lambda/K0Short
ratio are found, for Cu+Cu.


title: Mass formula for strange baryons in large $N_c$ QCD versus quark model

abstract:
  A previous work establishing a connection between a quark model, with
relativistic kinematics and a $Y$-confinement plus one gluon exchange, and the
$1/N_c$ expansion mass formula is extended to strange baryons. Both methods
predict values for the SU(3)-breaking mass terms which are in good agreement
with each other. Strange and nonstrange baryons are shown to exhibit Regge
trajectories with an equal slope, but with an intercept depending on the
strangeness. Both approaches agree on the value of the slope and of the
intercept and on the existence of a single good quantum number labeling the
baryons within a given Regge trajectory.


title: New results and Possibilities in K Physics

abstract:
  Several topics in the Kphysics together with the new facility J-Parc are
introduced.


title: Continuous Opinion Dynamics: Insights through Interactive Markov Chains

abstract:
  We reformulate the agent-based opinion dynamics models of Weisbuch-Deffuant
and Hegselmann-Krause as interactive Markov chains. So we switch the scope from
a finite number of n agents to a finite number of n opinion classes. Thus, we
will look at an infinite population distributed to opinion classes instead of
agents with real number opinions. The interactive Markov chains show similar
dynamical behavior as the agent-based models: stabilization and clustering. Our
framework leads to a discrete bifurcation diagram for each model which gives a
good view on the driving forces and the attractive states of the system. The
analysis shows that the emergence of minor clusters in the Weisbuch-Deffuant
model and of meta-stable states with very slow convergence to consensus in the
Hegselmann Krause model are intrinsic to the dynamical behavior.


title:
Optical colours of AGN in the Extended Chandra Deep Field South:
  Obscured black holes in early type galaxies

abstract:
  We investigate the optical colours of X-ray sources from the Extended Chandra
Deep Field South (ECDFS) using photometry from the COMBO-17 survey, aiming to
explore AGN - galaxy feedback models. The X-ray sources populate both the
``blue'' and the ``red sequence'' on the colour-magnitude diagram. However,
sources in the ``red sequence'' appear systematically more obscured. HST
imaging from the GEMS survey demonstrates that the nucleus does not affect
significantly the observed colours, and therefore red sources are early-type
systems. In the context of AGN feedback models, this means that there is still
remaining material after the initial ``blowout''. We argue that this material
could not be only left-over from the original merger, but a secondary cold gas
supplier (such as minor interactions or self-gravitational instabilities) must
also assist.


title:
Recent progress on the manipulation of single atoms in optical tweezers
  for quantum computing

abstract:
  This paper summarizes our recent progress towards using single rubidium atoms
trapped in an optical tweezer to encode quantum information. We demonstrate
single qubit rotations on this system and measure the coherence of the qubit.
We move the quantum bit over distances of tens of microns and show that the
coherence is reserved. We also transfer a qubit atom between two tweezers and
show no loss of coherence. Finally, we describe our progress towards
conditional entanglement of two atoms by photon emission and two-photon
interferences.


title:
Observation of strong-coupling effects in a diluted magnetic
  semiconductor (Ga,Fe)N

abstract:
  A direct observation of the giant Zeeman splitting of the free excitons in
(Ga,Fe)N is reported. The magnetooptical and magnetization data imply the
ferromagnetic sign and a reduced magnitude of the effective p-d exchange energy
governing the interaction between Fe^{3+} ions and holes in GaN, N_0 beta^(app)
= +0.5 +/- 0.2 eV. This finding corroborates the recent suggestion that the
strong p-d hybridization specific to nitrides and oxides leads to significant
renormalization of the valence band exchange splitting.


title: Cosmological and phenomenological consequences of string theories

abstract:
  The Standard Model is the low-energy limit of a microscopic theory which
includes extra dimensions and new symmetries. A part of my thesis consisted in
constructing a new class of models with two extra dimensions. We showed that
these models can drive a dynamical symmetry breaking in four dimensions. In
particular, they are dual to models with four fermions which need a
non-perturbative treatment. We also studied supersymmetry and its local
version, supergravity, in string theory inspired models with ten dimensions.
Extra fields called moduli are present after dimensional reduction and are
generically flat directions of the total potential. We constructed a model of
stabilisation for the moduli in which the supersymmetry breaking yields a light
gravitino mass of order 10 TeV. The cosmological constant can be adjusted to be
very small. Such models exhibit a promising phenomenology.


title: Collapse times for attractive Bose-Einstein condensates

abstract:
  We argue that the main mechanism for condensate collapse in an attractive
Bose-Einstein condensate is the loss of coherence between atoms a finite
distance apart, rather than the growth of the occupation number in
noncondensate modes. Since the former mechanism is faster than the latter by a
factor of approximately 3/2, this helps to dispel the apparent failure of field
theoretical models in predicting the collapse time of the condensate.


title:
The XMM-LSS catalogue: X-ray sources and associated optical data.
  Version I

abstract:
  Following the presentation of the XMM-LSS X-ray source detection package by
Pacaud et al., we provide the source lists for the first 5.5 surveyed square
degrees. The catalogues pertain to the [0.5-2] and [2-10] keV bands and contain
in total 3385 point-like or extended sources above a detection likelihood of 15
in either band. The agreement with deep logN-logS is excellent. The main
parameters considered are position, countrate, source extent with associated
likelihood values. A set of additional quantities such as astrometric
corrections and fluxes are further calculated while errors on the position and
countrate are deduced from simulations. We describe the construction of the
band-merged catalogue allowing rapid sub-sample selection and easy
cross-correlation with external multi-wavelength catalogues. A small optical
CFHTLS multi-band subset of objects is associated wich each source along with
an X-ray/optical overlay. We make the full X-ray images available in FITS
format. The data are available at CDS and, in a more extended form, at the
Milan XMM-LSS database.


title: Diffeomorphism Symmetry in the Lagrangian Formulation of Gravity

abstract:
  Starting from a knowledge of certain identities in the Lagrangian
description, the diffeomorphism transformations of metric and connection are
obtained for both the second order (metric) and the first order (Palatini)
formulations of gravity. The transformation laws of the connection and the
metric are derived independently in the Palatini formulation in contrast to the
metric formulation where the gauge variation of the connection is deduced from
the gauge variation of the metric.


title: Cesaro's integral formula for the Bell numbers (corrected)

abstract:
  M. E. Cesaro (1885) gave a quite remarkable expression for the Bell number
--the number of partitions of an n-element set -- as a definite integral. This
note is an exposition, correcting a typographical error in the original.


title:
Universal behaviour of interfaces in 2d and dimensional reduction of
  Nambu-Goto strings

abstract:
  We propose a simple effective model for the description of interfaces in 2d
statistical models, based on the first-order treatment of an action
corresponding to the length of the interface. The universal prediction of this
model for the interface free energy agrees with the result of an exact
calculation in the case of the 2d Ising model. This model appears as a
dimensional reduction of the Nambu-Goto stringy description of interfaces in
3d, i.e., of the capillary wave model.


title:
Influence of the L21 ordering degree on the magnetic properties in
  Co2MnSi Heusler films

abstract:
  We report on the influence of the improved L21 ordering degree on the
magnetic properties of Co2MnSi Heusler films. Different fractions of the L21
phase are obtained by different post-growth annealing temperatures ranging from
350 degC to 500 degC. Room temperature magneto-optical Kerr effect measurements
reveal an increase of the coercivity at an intermediate annealing temperature
of 425 degC, which is a fingerprint of an increased number of pinning centers
at this temperature. Furthermore, Brillouin light scattering studies show that
the improvement of the L21 order in the Co2MnSi films is correlated with a
decrease of the saturation magnetization by about 9%. The exchange stiffness
constant of Co2MnSi, however, increases by about 8% when the L21 order is
improved. Moreover, we observe a drop of the cubic anisotropy constant K1 by a
factor of 10 for an increasing amount of the L21 phase.