title:
Multilayer Perceptron with Functional Inputs: an Inverse Regression
  Approach

abstract:
  Functional data analysis is a growing research field as more and more
practical applications involve functional data. In this paper, we focus on the
problem of regression and classification with functional predictors: the model
suggested combines an efficient dimension reduction procedure [functional
sliced inverse regression, first introduced by Ferr\'e & Yao (Statistics, 37,
2003, 475)], for which we give a regularized version, with the accuracy of a
neural network. Some consistency results are given and the method is
successfully confronted to real-life data.


title:
Attosecond electron pulses from interference of above-threshold de
  Broglie waves

abstract:
  It is shown that the the interference of above-threshold electron de Broglie
waves, generated by an intense laser pulse at a metal surface yields attosecond
electron pulses. This inerference is an analogon of the superposition of high
harmonics generated from rare gas atoms, resulting in trains of attosecond
light pulses.Owing to the inherent kinematic dispersion, the propagation of
attosecond de Broglie waves in vacuum is very different from that of attosecond
light pulses, which propagate without changing shape. Above the metal surface
there are "collaps bands" and "revival layers" of the electron current even at
macroscopic distances. In the range of parameters considered, the maximum value
of the current densities of such ultrashort electron pulses has been estimated
to be of order of couple of tenths of milliamps per square centimeters.


title:
Self-Assembly of Monatomic Complex Crystals and Quasicrystals with a
  Double-Well Interaction Potential

abstract:
  For the study of crystal formation and dynamics we introduce a simple
two-dimensional monatomic model system with a parametrized interaction
potential. We find in molecular dynamics simulations that a surprising variety
of crystals, a decagonal and a dodecagonal quasicrystal are self-assembled. In
the case of the quasicrystals the particles reorder by phason flips at elevated
temperatures. During annealing the entropically stabilized decagonal
quasicrystal undergoes a reversible phase transition at 65% of the melting
temperature into an approximant, which is monitored by the rotation of the de
Bruijn surface in hyperspace.


title: Riemannian level-set methods for tensor-valued data

abstract:
  We present a novel approach for the derivation of PDE modeling
curvature-driven flows for matrix-valued data. This approach is based on the
Riemannian geometry of the manifold of Symmetric Positive Definite Matrices
Pos(n).


title: Transit and secondary eclipse photometry in the near-infrared

abstract:
  Near-infrared photometry of transiting extrasolar planets can be of great
scientific value. It is however not straightforward to reach the necessary
millimagnitude precision. Here we report on our attempts to observe transits
and secondary eclipses of several extrasolar planets at 2.2 micron. Best
results have been obtained on OGLE-TR-113b using the SOFI near-infrared camera
on ESO's New Technology Telescope. Its K-band transit shows a remarkably flat
bottom indicating low stellar limb darkening. Secondary eclipse photometry has
resulted in a formal 3 sigma detection, but residual systematic effects make
this detection rather uncertain.


title:
Spin relaxation due to the Bir-Aronov-Pikus mechanism in intrinsic and
  $p$-type GaAs quantum wells from a fully microscopic approach

abstract:
  We study the electron spin relaxation in intrinsic and $p$-type (001) GaAs
quantum wells by constructing and numerically solving the kinetic spin Bloch
equations. All the relevant scatterings are explicitly included, especially the
spin-flip electron-heavy hole exchange scattering which leads to the
Bir-Aronov-Pikus spin relaxation. We show that, due to the neglection of the
nonlinear terms in the electron-heavy hole exchange scattering in the
Fermi-golden-rule approach, the spin relaxation due to the Bir-Aronov-Pikus
mechanism is greatly exaggerated at moderately high electron density and low
temperature in the literature. We compare the spin relaxation time due to the
Bir-Aronov-Pikus mechanism with that due to the D'yakonov-Perel' mechanism
which is also calculated from the kinetic spin Bloch equations with all the
scatterings, especially the spin-conserving electron-electron and
electron-heavy hole scatterings, included. We find that, in intrinsic quantum
wells, the effect from the Bir-Aronov-Pikus mechanism is much smaller than that
from the D'yakonov-Perel' mechanism at low temperature, and it is smaller by no
more than one order of magnitude at high temperature. In $p$-type quantum
wells, the spin relaxation due to the Bir-Aronov-Pikus mechanism is also much
smaller than the one due to the D'yakonov-Perel' mechanism at low temperature
and becomes comparable to each other at higher temperature when the hole
density and the width of the quantum well are large enough. We claim that
unlike in the bulk samples, the Bir-Aronov-Pikus mechanism hardly dominates the
spin relaxation in two-dimensional samples.


title: A new analysis of Poincar\'e dodecahedral space model

abstract:
  The full three-year WMAP results (WMAP3) reinforce the absence of large-angle
correlations at scales greater than 60 degrees. The Poincare dodecahedral space
(PDS) model model, which may naturally explain such features, thus remains a
plausible cosmological model, despite recent controversy about whether matched
circle searches would or would not push the topology beyond the horizon. Here,
we have used new eigenmode calculations of the dodecahedral space to predict
the cosmic microwave background (CMB) temperature fluctuations in such models,
with an improved angular resolution. We have simulated CMB maps and confirmed
the expected presence of matching circles. For a set of plausible cosmological
parameters, we have derived the angular power spectrum of the CMB up to large
wavenumbers. Comparison with the WMAP3 observations confirms a remarkable fit
with a PDS model, for a value $\Omega_0 = 1.018$ of the average total energy
density.


title: Weakly null sequences with upper estimates

abstract:
  We prove that if $(v_i)$ is a normalized basic sequence and X is a Banach
space such that every normalized weakly null sequence in X has a subsequence
that is dominated by $(v_i)$, then there exists a uniform constant $C\geq1$
such that every normalized weakly null sequence in X has a subsequence that is
C-dominated by $(v_i)$. This extends a result of Knaust and Odell, who proved
this for the cases in which $(v_i)$ is the standard basis for $\ell_p$ or
$c_0$.


title: Determining the Mass for a Light Gravitino

abstract:
  Gauge mediated supersymmetry breaking scenarios with an ultra-light gravitino
of mass m_{3/2}=1-10 eV are very interesting, since there is no cosmological
gravitino problem. We propose a new experimental determination of the gravitino
mass for such an ultra-light gravitino, by measuring a branching ratio of two
decay modes of sleptons.


title: Joint free energy distribution in the random directed polymer problem

abstract:
  We consider two configurations of a random directed polymer of length L
confined to a plane and ending in two points separated by 2u. Defining the mean
free energy $\bar F$ and the free energy difference F' of the two
configurations, we determine the joint distribution function P_{L,u}(\bar F,F')
using the replica approach. We find that for large L and large negative free
energies $\bar F$, the joint distribution function factorizes into longitudinal
(P_{L,u} (\bar F)) and transverse (P_{u}(F')) components, which furthermore
coincide with results obtained prevously via different independent routes.


title: Non static Global monopole in Lyra geometry

abstract:
  A class of non static solutions around a global monopole resulting from the
breaking of a global S0(3) symmetry based on Lyra geometry are obtained. The
solutions are obtained using the functional separability of the metric
coefficients. We have shown that the monopole exerts attractive gravitational
effects on test particles.


title:
The connection between field-theory and the equations for material
  sistems

abstract:
  The existing field theories are based on the properties of closed exterior
forms, which correspond to conservation laws for physical fields.
  In the present paper it is shown that closed exterior forms corresponding to
field theories are obtained from the equations modelling conservation (balance)
laws for material sistems (material media).
  The process of obtaining closed exterior forms demonstrates the connection
between field-theory equations and the equations for material sistems and
points to the fact that the foundations of field theories must be conditioned
by the properties of equations conservation laws for material sistems.


title:
On the multifractal statistics of the local order parameter at random
  critical points : application to wetting transitions with disorder

abstract:
  Disordered systems present multifractal properties at criticality. In
particular, as discovered by Ludwig (A.W.W. Ludwig, Nucl. Phys. B 330, 639
(1990)) on the case of diluted two-dimensional Potts model, the moments
$\bar{\rho^q(r)}$ of the local order parameter $\rho(r)$ scale with a set
$x(q)$ of non-trivial exponents $x(q) \neq q x(1)$. In this paper, we revisit
these ideas to incorporate more recent findings: (i) whenever a multifractal
measure $w(r)$ normalized over space $ \sum_r w(r)=1$ occurs in a random
system, it is crucial to distinguish between the typical values and the
disorder averaged values of the generalized moments $Y_q =\sum_r w^q(r)$, since
they may scale with different generalized dimensions $D(q)$ and $\tilde D(q)$
(ii) as discovered by Wiseman and Domany (S. Wiseman and E. Domany, Phys Rev E
{\bf 52}, 3469 (1995)), the presence of an infinite correlation length induces
a lack of self-averaging at critical points for thermodynamic observables, in
particular for the order parameter. After this general discussion valid for any
random critical point, we apply these ideas to random polymer models that can
be studied numerically for large sizes and good statistics over the samples. We
study the bidimensional wetting or the Poland-Scheraga DNA model with loop
exponent $c=1.5$ (marginal disorder) and $c=1.75$ (relevant disorder). Finally,
we argue that the presence of finite Griffiths ordered clusters at criticality
determines the asymptotic value $x(q \to \infty) =d$ and the minimal value $
\alpha_{min}=D(q \to \infty)=d-x(1) $ of the typical multifractal spectrum
$f(\alpha)$.


title:
Evaporation of buffer gas-thermalized anions out of a multipole rf ion
  trap

abstract:
  We identify plain evaporation of ions as the fundamental loss mechanism out
of a multipole ion trap. Using thermalized negative Cl- ions we find that the
evaporative loss rate is proportional to a Boltzmann factor. This thermodynamic
description sheds new light on the dynamics of particles in time-varying
confining potentials. It specifically allows us to extract the effective depth
of the ion trap as the activation energy for evaporation. As a function of the
rf amplitude we find two distinct regimes related to the stability of motion of
the trapped ions. For low amplitudes the entire trap allows for stable motion
and the trap depth increases with the rf field. For larger rf amplitudes,
however, rapid energy transfer from the field to the ion motion can occur at
large trap radii, which leads to a reduction of the effective trapping volume.
In this regime the trap depth decreases again with increasing rf amplitude. We
give an analytical parameterization of the trap depth for various multipole
traps that allows predictions of the most favorable trapping conditions.


title: The centralizer of a C1 generic diffeomorphism is trivial

abstract:
  In this announcement, we describe the solution in the C1 topology to a
question asked by S. Smale on the genericity of trivial centralizers: the set
of diffeomorphisms of a compact connected manifold with trivial centralizer
residual in Diff^1 but does not contain an open and dense subset.


title: Langevin dynamics of the pure SU(2) deconfining transition

abstract:
  We investigate the dissipative real-time evolution of the order parameter for
the deconfining transition in the pure SU(2) gauge theory. The approach to
equilibrium after a quench to temperatures well above the critical one is
described by a Langevin equation. To fix completely the markovian Langevin
dynamics we choose the dissipation coefficient, that is a function of the
temperature, guided by preliminary Monte Carlo simulations for various
temperatures. Assuming a relationship between Monte Carlo time and real time,
we estimate the delay in thermalization brought about by dissipation and noise.


title:
Self assembly of a model multicellular organism resembling the
  Dictyostelium slime molds

abstract:
  The evolution of multicellular organisms from monocellular ancestors
represents one of the greatest advances of the history of life. The assembly of
such multicellular organisms requires signalling and response between cells:
over millions of years these signalling processes have become extremely
sophisticated and refined by evolution, such that study of modern organisms may
not be able to shed much light on the original ancient processes . Here we are
interested in determining how simple a signalling method can be, while still
achieving self-assembly. In 2D a coupled cellular automaton/differential
equation approach models organisms and chemotaxic chemicals, producing
spiralling aggregation. In 3D Lennard-Jones-like particles are used to
represent single cells, and their evolution in response to signalling is
followed by molecular dynamics. It is found that if a single cell is able to
emit a signal which induces others to move towards it, then a colony of
single-cell organisms can assemble into shapes as complex as a tower, a ball
atop a stalk, or a fast-moving slug. The similarity with the behaviour of
modern Dictyostelium slime molds signalling with cyclic adenosine monophosphate
(cAMP) is striking.


title: Canonical Formulation of pp-waves

abstract:
  We construct a Hamiltonian formulation for the class of plane-fronted
gravitational waves with parallel rays (pp-waves). Because of the existence of
a light-like Killing vector, the dynamics is effectively reduced to a 2+1
evolution with "time" chosen to be light-like. In spite of the vanishing action
this allows us to geometrically identify a symplectic form as well as dynamical
Hamiltonian, thus casting the system into canonical form.


title: Quantum theory of successive projective measurements

abstract:
  We show that a quantum state may be represented as the sum of a joint
probability and a complex quantum modification term. The joint probability and
the modification term can both be observed in successive projective
measurements. The complex modification term is a measure of measurement
disturbance. A selective phase rotation is needed to obtain the imaginary part.
This leads to a complex quasiprobability, the Kirkwood distribution. We show
that the Kirkwood distribution contains full information about the state if the
two observables are maximal and complementary. The Kirkwood distribution gives
a new picture of state reduction. In a nonselective measurement, the
modification term vanishes. A selective measurement leads to a quantum state as
a nonnegative conditional probability. We demonstrate the special significance
of the Schwinger basis.


title:
Comment on ``Collapse of Coherent Quasiparticle States in
  $\theta$-(BEDT-TTF)$_2$I$_3$ Observed by Optical Spectroscopy''

abstract:
  Recently, Takenaka et al. reported that the resistivity rho(T) of
theta-(BEDT-TTF)_2I_3 (theta-ET) exceeds the Ioffe-Regel resistivity by a
factor of 50 at large temperatures T (``bad metal''). This was ascribed to
strong correlation. We argue that the optical conductivity sigma(omega) implies
that correlation is not very strong, and that correlation gives no general
strong suppression of sigma(omega). The large rho(T) is primarily due to a
downturn in sigma(omega) at small omega, earlier emphasized by Takenaka et al.
as the explanation for bad metal behavior of high-T_c cuprates. We argue,
however, that for cuprates strong correlation is the main effect. The data of
Takenaka et al. puts theta-ET in a new class of bad metals.


title: Two-pion-exchange in the non-mesonic weak decay of $\Lambda$-hypernuclei

abstract:
  The non-mesonic weak decay of $\Lambda$--hypernuclei is studied within a
one-meson-exchange potential supplemented by a chirally motivated
two-pion-exchange mechanism. The effects of final state interactions on the
outgoing nucleons are also taken into account. In view of the severe
discrepancies between theoretical expectations and experimental data,
particular attention is payed to the asymmetry of the protons emitted by
polarized hypernuclei. The one-meson-exchange model describes the non-mesonic
rates and the neutron-to-proton ratio satisfactorily but predicts a too large
and negative asymmetry parameter. The uncorrelated and correlated two-pion
mechanisms change the rates moderately, thus maintaining the agreement with
experiment. The modification in the strength and sign of some decay amplitudes
becomes crucial and produces asymmetry parameters which lie well within the
experimental observations.


title: Cosmological perturbations in Palatini modified gravity

abstract:
  Two approaches to the study of cosmological density perturbations in modified
theories of Palatini gravity have recently been discussed. These utilise,
respectively, a generalisation of Birkhoff's theorem and a direct linearization
of the gravitational field equations. In this paper these approaches are
compared and contrasted. The general form of the gravitational lagrangian for
which the two frameworks yield identical results in the long-wavelength limit
is derived. This class of models includes the case where the lagrangian is a
power-law of the Ricci curvature scalar. The evolution of density perturbations
in theories of the type $f(R)=R-c /R^ b$ is investigated numerically. It is
found that the results obtained by the two methods are in good agreement on
sufficiently large scales when the values of the parameters (b,c) are
consistent with current observational constraints. However, this agreement
becomes progressively poorer for models that differ significantly from the
standard concordance model and as smaller scales are considered.


title:
Coordination for a Group of Autonomous Mobile Agents with Multiple
  Leaders

abstract:
  In this paper, we consider the coordination control of a group of autonomous
mobile agents with multiple leaders. Different interconnection topologies are
investigated. At first, a necessary and sufficient condition is proved in the
case of fixed interconnection topology. Then a sufficient condition is proposed
when the interconnection topology is switched. With a simple first-order
dynamics model by using the neighborhood rule, both results show that the group
behavior of the agents will converge to the polytope formed by the leaders.


title:
Low energy cut-offs and hard X-ray spectra in high-z radio-loud quasars:
  the Suzaku view of RBS315

abstract:
  We present the results from the Suzaku observation of the powerful radio-loud
quasar RBS315 (z=2.69), for which a previous XMM-Newton observation showed an
extremely flat X-ray continuum up to 10 keV (photon index Gamma=1.26) and
indications of strong intrinsic absorption (N_H~10^22 cm^{-2} assuming neutral
gas). The instrument for hard X-rays HXD/PIN allows us a detection of the
source up to 50 keV. The broad-band continuum (0.5-50 keV) can be well modeled
with a power-law with slope Gamma=1.5 (definitively softer than the continuum
measured by XMM-Newton) above 1 keV with strong deficit of soft photons. The
low-energy cut-off can be well fitted either with intrinsic absorption (with
column density N_H~10^22 cm^{-2} in the quasar rest frame) or with a break in
the continuum, with an extremely hard (Gamma =0.7) power-law below 1 keV. We
construct the Spectral Energy Distribution of the source, using also optical-UV
measurements obtained through a quasi-simultaneous UVOT/SWIFT observation. The
shape of the SED is similar to that of other Flat Spectrum Radio Quasars
(FSRQs) with similar power, making this source an excellent candidate for the
detection in gamma-rays by GLAST. We model the SED with the synchrotron-Inverse
Compton model usually applied to FSRQs, showing that the deficit of soft
photons can be naturally interpreted as due to an intrinsic curvature of the
spectrum near the low energy end of the IC component rather than to intrinsic
absorption, although the latter possibility cannot be ruled out. We propose
that in at least a fraction of the radio-loud QSOs at high redshift the cut-off
in the soft X-ray band can be explained in a similar way. Further studies are
required to distinguish between the two alternatives.


title:
Instanton representation of Plebanski gravity: Application to the
  Schwarzchild metric

abstract:
  In this paper we apply the instanton representation method to the
construction of spherically symmetric blackhole general relativity solutions.
The instanton representation implies the existence of additional Type D
solutions which are axially symmetric. We explicitly construct these solutions,
which are fully consistent with Birkhoff's theorem.


title:
Hermitian manifolds of pointwise constant antiholomorphic sectional
  curvatures

abstract:
  In dimension greater than four, we prove that if a Hermitian non-Kaehler
manifold is of pointwise constant antiholomorphic sectional curvatures, then it
is of constant sectional curvatures.


title: Spin-polarized transport in II-VI magnetic resonant tunneling devices

abstract:
  We investigate electronic transport through II-VI semiconductor resonant
tunneling structures containing diluted magnetic impurities. Due to the
exchange interaction between the conduction electrons and the impurities, there
arises a giant Zeeman splitting in the presence of a moderately low magnetic
field. As a consequence, when the quantum well is magnetically doped the
current-voltage characteristics shows two peaks corresponding to transport for
each spin channel. This behavior is experimentally observed and can be
reproduced with a simple tunneling model. The model thus allows to analyze
other configurations. First, we further increase the magnetic field, which
leads to a spin polarization of the electronic current injected from the leads,
thus giving rise to a relative change in the current amplitude. We demonstrate
that the spin polarization in the emitter can be determined from such a change.
Furthermore, in the case of a magnetically doped injector our model shows a
large increase in peak amplitude and a shift of the resonance to higher
voltages as the external field increases. We find that this effect arises from
a combination of giant Zeeman splitting, 3-D incident distribution and broad
resonance linewidth.


title:
General Relativistic Flux Modulations from Disk Instabilities in
  Sagittarius A*

abstract:
  Near-IR and X-ray flares have been detected from the supermassive black hole
Sgr A* at the center of our Galaxy with a (quasi)-period of ~17-20 minutes,
suggesting an emission region only a few Schwarzschild radii above the event
horizon. The latest X-ray flare, detected with XMM-Newton, is notable for its
detailed lightcurve, yielding not only the highest quality period thus far, but
also important structure reflecting the geometry of the emitting region. Recent
MHD simulations of Sgr A*'s disk have demonstrated the growth of a Rossby wave
instability, that enhances the accretion rate for several hours, possibly
accounting for the observed flares. In this Letter, we carry out ray-tracing
calculations in a Schwarzschild metric to determine as accurately as possible
the lightcurve produced by general relativistic effects during such a
disruption. We find that the Rossby wave induced spiral pattern in the disk is
an excellent fit to the data, implying a disk inclination angle of ~77 deg.
Note, however, that if this association is correct, the observed period is not
due to the underlying Keplerian motion but, rather, to the pattern speed. The
favorable comparison between the observed and simulated lightcurves provides
important additional evidence that the flares are produced in Sgr A*'s inner
disk.


title: Pulse-Shape discrimination with the Counting Test Facility

abstract:
  Pulse shape discrimination (PSD) is one of the most distinctive features of
liquid scintillators. Since the introduction of the scintillation techniques in
the field of particle detection, many studies have been carried out to
characterize intrinsic properties of the most common liquid scintillator
mixtures in this respect. Several application methods and algorithms able to
achieve optimum discrimination performances have been developed. However, the
vast majority of these studies have been performed on samples of small
dimensions. The Counting Test Facility, prototype of the solar neutrino
experiment Borexino, as a 4 ton spherical scintillation detector immersed in
1000 tons of shielding water, represents a unique opportunity to extend the
small-sample PSD studies to a large-volume setup. Specifically, in this work we
consider two different liquid scintillation mixtures employed in CTF,
illustrating for both the PSD characterization results obtained either with the
processing of the scintillation waveform through the optimum Gatti's method, or
via a more conventional approach based on the charge content of the
scintillation tail. The outcomes of this study, while interesting per se, are
also of paramount importance in view of the expected Borexino detector
performances, where PSD will be an essential tool in the framework of the
background rejection strategy needed to achieve the required sensitivity to the
solar neutrino signals.


title: Gravitational Wave Constraints on DBI Inflation

abstract:
  An upper bound on the amplitude of the primordial gravitational wave spectrum
generated during ultra-violet DBI inflation is derived. The bound is
insensitive to the form of the inflaton potential and the warp factor of the
compactified dimensions and can be expressed entirely in terms of observational
parameters once the volume of the five-dimensional sub-manifold of the throat
has been specified. For standard type IIB compactification schemes, the bound
predicts undetectably small tensor perturbations with a tensor-scalar ratio $r
< 10^{-7}$. This is incompatible with a corresponding lower limit of $r > 0.1
(1-n_s)$, which applies to any model that generates a red spectral index $n_s
<1$ and a potentially detectable non-Gaussianity in the curvature perturbation.
Possible ways of evading these bounds in more general DBI-type scenarios are
discussed and a multiple-brane model is investigated as a specific example.


title:
New paradox in the special theory of relativity generated by the string
  dynamics

abstract:
  It is proved that the definition of simultaneity by Einstein leads to the
paradox motion of he string from the viewpoint of the observer in the inertial
system S' moving with velocity v with regard to the inertial system S.


title:
The scalar wave equation in a non-commutative spherically symmetric
  space-time

abstract:
  Recent work in the literature has studied a version of non-commutative
Schwarzschild black holes where the effects of non-commutativity are described
by a mass function depending on both the radial variable r and a
non-commutativity parameter theta. The present paper studies the asymptotic
behaviour of solutions of the zero-rest-mass scalar wave equation in such a
modified Schwarzschild space-time in a neighbourhood of spatial infinity. The
analysis is eventually reduced to finding solutions of an inhomogeneous
Euler--Poisson--Darboux equation, where the parameter theta affects explicitly
the functional form of the source term. Interestingly, for finite values of
theta, there is full qualitative agreement with general relativity: the
conformal singularity at spacelike infinity reduces in a considerable way the
differentiability class of scalar fields at future null infinity. In the
physical space-time, this means that the scalar field has an asymptotic
behaviour with a fall-off going on rather more slowly than in flat space-time.


title: Decoherence of Highly Mixed Macroscopic Quantum Superpositions

abstract:
  It is known that a macroscopic quantum superposition (MQS), when it is
exposed to environment, decoheres at a rate scaling with the separation of its
component states in phase space. This is more or less consistent with the well
known proposition that a more macroscopic quantum state is reduced more quickly
to a classical state in general. Effects of initial mixedness, however, on the
subsequent decoherence of MQSs have been less known. In this paper, we study
the evolution of a highly mixed MQS interacting with an environment, and
compare it with that of a pure MQS having the same size of the central distance
between its component states. Although the decoherence develops more rapidly
for the mixed MQS in short times, its rate can be significantly suppressed
after a certain time and becomes smaller than the decoherence rate of its
corresponding pure MQS. In an optics experiment to generate a MQS, our result
has a practical implication that nonclassicality of a MQS can be still
observable in moderate times even though a large amount of noise is added to
the initial state.


title:
On $p$-adic Gibbs measures of countable state Potts model on the Cayley
  tree

abstract:
  In the present paper we consider countable state $p$-adic Potts model on the
Cayley tree. A construction of $p$-adic Gibbs measures which depends on weights
$\l$ is given, and an investigation of such measures is reduced to examination
of an infinite-dimensional recursion equation. Studying of the derived equation
under some condition on weights, we prove absence of the phase transition. Note
that the condition does not depend on values of the prime $p$, and an analogues
fact is not true when the number of spins is finite. For homogeneous model it
is shown that the recursive equation has only one solution under that condition
on weights. This means that there is only one $p$-adic Gibbs measure $\m_\l$.
The boundedness of the measure is also established. Moreover, continuous
dependence the measure $\m_\l$ on $\l$ is proved. At the end we formulate one
limit theorem for $\m_\l$.


title: Measurement of masses and lifetimes of B hadrons

abstract:
  We present recent measurements by the CDF and D0 Collaborations at the
Tevatron Collider on the masses and lifetimes of B hadrons. The results are
compared to predictions based on Heavy Quark Effective Theory, lattice gauge
theory, and quark models.


title:
Strong deflection limit of black hole gravitational lensing with
  arbitrary source distances

abstract:
  The gravitational field of supermassive black holes is able to strongly bend
light rays emitted by nearby sources. When the deflection angle exceeds $\pi$,
gravitational lensing can be analytically approximated by the so-called strong
deflection limit. In this paper we remove the conventional assumption of
sources very far from the black hole, considering the distance of the source as
an additional parameter in the lensing problem to be treated exactly. We find
expressions for critical curves, caustics and all lensing observables valid for
any position of the source up to the horizon. After analyzing the spherically
symmetric case we focus on the Kerr black hole, for which we present an
analytical 3-dimensional description of the higher order caustic tubes.


title:
Concavity, Abel-transform and the Abel-inverse theorem in smooth
  complete toric varieties

abstract:
  We extend the usual projective Abel-Radon transform to the larger context of
a smooth complete toric variety X. We define and study toric concavity attached
to an algebraic splitting vector bundle on X and we prove a toric version of
the Abel-inverse theorem.


title: MCHIT - Monte Carlo model for proton and heavy-ion therapy

abstract:
  We study the propagation of nucleons and nuclei in tissue-like media within a
Monte Carlo Model for Heavy-ion Therapy (MCHIT) based on the GEANT4 toolkit
(version 8.2). The model takes into account fragmentation of projectile nuclei
and secondary interactions of produced nuclear fragments. Model predictions are
validated with available experimental data obtained for water and PMMA phantoms
irradiated by monoenergetic carbon-ion beams. The MCHIT model describes well
(1) the depth-dose distributions in water and PMMA, (2) the doses measured for
fragments of certain charge, (3) the distributions of positron emitting nuclear
fragments produced by carbon-ion beams, and (4) the energy spectra of secondary
neutrons measured at different angles to the beam direction. Radial dose
profiles for primary nuclei and for different projectile fragments are
calculated and discussed as possible input for evaluation of biological dose
distributions. It is shown that at the periphery of the transverse dose profile
close to the Bragg peak the dose from secondary nuclear fragments is comparable
to the dose from primary nuclei.


title: Principal Component Analysis of Gamma-Ray Bursts' Spectra

abstract:
  Principal component analysis is a statistical method, which lowers the number
of important variables in a data set. The use of this method for the bursts'
spectra and afterglows is discussed in this paper. The analysis indicates that
three principal components are enough among the eight ones to describe the
variablity of the data. The correlation between spectral index alpha and the
redshift suggests that the thermal emission component becomes more dominant at
larger redshifts.


title:
Functional calculus of Dirac operators and complex perturbations of
  Neumann and Dirichlet problems

abstract:
  We prove that the Neumann, Dirichlet and regularity problems for divergence
form elliptic equations in the half space are well posed in $L_2$ for small
complex $L_\infty$ perturbations of a coefficient matrix which is either real
symmetric, of block form or constant. All matrices are assumed to be
independent of the transversal coordinate. We solve the Neumann, Dirichlet and
regularity problems through a new boundary operator method which makes use of
operators in the functional calculus of an underlaying first order Dirac type
operator. We establish quadratic estimates for this Dirac operator, which
implies that the associated Hardy projection operators are bounded and depend
continuously on the coefficient matrix. We also prove that certain transmission
problems for $k$-forms are well posed for small perturbations of block
matrices.


title: Arithmetic of curves over two dimensional local field

abstract:
  We study the class field theory of curve defined over two dimensional local
field. The approch used here is a combination of the work of Kato-Saito, and
Yoshida where the base field is one dimensional


title: Power Allocation for Discrete-Input Non-Ergodic Block-Fading Channels

abstract:
  We consider power allocation algorithms for fixed-rate transmission over
Nakagami-m non-ergodic block-fading channels with perfect transmitter and
receiver channel state information and discrete input signal constellations
under both short- and long-term power constraints. Optimal power allocation
schemes are shown to be direct applications of previous results in the
literature. We show that the SNR exponent of the optimal short-term scheme is
given by the Singleton bound. We also illustrate the significant gains
available by employing long-term power constraints. Due to the nature of the
expressions involved, the complexity of optimal schemes may be prohibitive for
system implementation. We propose simple sub-optimal power allocation schemes
whose outage probability performance is very close to the minimum outage
probability obtained by optimal schemes.


title:
More Efficient Algorithms and Analyses for Unequal Letter Cost
  Prefix-Free Coding

abstract:
  There is a large literature devoted to the problem of finding an optimal
(min-cost) prefix-free code with an unequal letter-cost encoding alphabet of
size. While there is no known polynomial time algorithm for solving it
optimally there are many good heuristics that all provide additive errors to
optimal. The additive error in these algorithms usually depends linearly upon
the largest encoding letter size.
  This paper was motivated by the problem of finding optimal codes when the
encoding alphabet is infinite. Because the largest letter cost is infinite, the
previous analyses could give infinite error bounds. We provide a new algorithm
that works with infinite encoding alphabets. When restricted to the finite
alphabet case, our algorithm often provides better error bounds than the best
previous ones known.


title:
Strong and radiative decays of the Ds0*(2317) meson in the DK-molecule
  picture

abstract:
  We consider a possible interpretation of the new charm-strange meson
Ds0*(2317) as a hadronic molecule - a bound state of D and K mesons. Using an
effective Lagrangian approach we calculate the strong Ds0* to Ds pi0 and
radiative Ds0* to Ds* gamma decays. A new impact related to the DK molecular
structure of the Ds0*(2317) meson is that the presence of u(d) quarks in the D
and K mesons gives rise to a direct strong isospin-violating transition Ds0* to
Ds pi0 in addition to the decay mechanism induced by eta-pi0 mixing considered
previously. We show that the direct transition dominates over the eta-pi0
mixing transition in the Ds0* to Ds pi0 decay. Our results for the partial
decay widths are consistent with previous calculations.


title:
Note on the inelastic neutron scattering spectrum in cuprate
  superconductors

abstract:
  The inelastic neutron scattering spectrum in cuprate superconductors is
discussed on the basis of the itinerant-localized duality model for strongly
correlated electrons. In Appendix the consistency with recent rigorous
theoretical result on ARPES is discussed.


title: A local Paley-Wiener theorem for compact symmetric spaces

abstract:
  The Fourier coefficients of a smooth $K$-invariant function on a compact
symmetric space $M=U/K$ are given by integration of the function against the
spherical functions. For functions with support in a neighborhood of the
origin, we describe the size of the support by means of the exponential type of
a holomorphic extension of the Fourier coefficients


title: Tuning Kondo physics in Graphene with gate voltage

abstract:
  We show theoretically that graphene, which exhibits a massless Dirac like
spectrum for its electrons, can exhibit unconventional Kondo effect that can be
tuned by an experimentally controllable applied gate voltage. We demonstrate
the presence of a finite critical Kondo coupling strength in neutral graphene.
We discuss the possibility of multichannel Kondo effect in this system which
might lead to a non-Fermi liquid like ground state and provide a discussion of
possible experimental realization of Kondo phenomenon in graphene.


title: A local gauge invariant infrared regularization of the Yang-Mills theory

abstract:
  A local gauge invariant infrared regularization for the Yang-Mills theory is
constructed on the basis of a higher derivative formulation of the model.


title: Making graphene visible

abstract:
  Microfabrication of graphene devices used in many experimental studies
currently relies on the fact that graphene crystallites can be visualized using
optical microscopy if prepared on top of silicon wafers with a certain
thickness of silicon dioxide. We study graphene's visibility and show that it
depends strongly on both thickness of silicon dioxide and light wavelength. We
have found that by using monochromatic illumination, graphene can be isolated
for any silicon dioxide thickness, albeit 300 nm (the current standard) and,
especially, approx. 100 nm are most suitable for its visual detection. By using
a Fresnel-law-based model, we quantitatively describe the experimental data
without any fitting parameters.


title: Photodesorption of CO ice

abstract:
  At the high densities and low temperatures found in star forming regions, all
molecules other than H2 should stick on dust grains on timescales shorter than
the cloud lifetimes. Yet these clouds are detected in the millimeter lines of
gaseous CO. At these temperatures, thermal desorption is negligible and hence a
non-thermal desorption mechanism is necessary to maintain molecules in the gas
phase. Here, the first laboratory study of the photodesorption of pure CO ice
under ultra high vacuum is presented, which gives a desorption rate of 3E-3 CO
molecules per UV (7-10.5 eV) photon at 15 K. This rate is factors of 1E2-1E5
larger than previously estimated and is comparable to estimates of other
non-thermal desorption rates. The experiments constrains the mechanism to a
single photon desorption process of ice surface molecules. The measured
efficiency of this process shows that the role of CO photodesorption in
preventing total removal of molecules in the gas has been underestimated.


title: Exact dimer ground states for a continuous family of quantum spin chains

abstract:
  Using the matrix product formalism, we define a multi-parameter family of
spin models on one dimensional chains, with nearest and next-nearest neighbor
anti-ferromagnetic interaction for which exact analytical expressions can be
found for its doubly degenerate ground states. The family of Hamiltonians which
we define, depend on 5 continuous parameters and the Majumdar-Ghosh model is a
particular point in this parameter space. Like the Majumdar-Ghosh model, the
doubly degenerate ground states of our models have a very simple structure,
they are the product of entangled states on adjacent sites. In each of these
states there is a non-zero staggered magnetization, which vanishes when we take
their translation-invariant combination as the new ground states. At the
Majumdar-Ghosh point, these entangled states become the spin-singlets
pertaining to this model. We will also calculate in closed form the two point
correlation functions, both for finite size of the chain and in the
thermodynamic limit.


title: The Complexity of Games on Higher Order Pushdown Automata

abstract:
  We prove an n-EXPTIME lower bound for the problem of deciding the winner in a
reachability game on Higher Order Pushdown Automata (HPDA) of level n. This
bound matches the known upper bound for parity games on HPDA. As a consequence
the mu-calculus model checking over graphs given by n-HPDA is n-EXPTIME
complete.


title:
Magnetic Excitations in La2CuO4 probed by Indirect Resonant Inelastic
  X-ray Scattering

abstract:
  Recent experiments on La$_2$CuO$_4$ suggest that indirect resonant inelastic
X-ray scattering (RIXS) might provide a probe for transversal spin dynamics. We
present in detail a systematic expansion of the relevant magnetic RIXS cross
section by using the ultrashort core-hole lifetime (UCL) approximation. We
compute the scattering intensity and its momentum dependence in leading order
of the UCL expansion. The scattering is due to two-magnon processes and is
calculated within a linear spin-wave expansion of the Heisenberg spin model for
this compound, including longer range and cyclic spin interactions. We observe
that the latter terms in the Hamiltonian enhance the first moment of the
spectrum if they strengthen the antiferromagnetic ordering. The theoretical
spectra agree very well with experimental data, including the observation that
scattering intensity vanishes for the transferred momenta ${\bf q} = (0,0)$ and
${\bf q} = (\pi,\pi)$. We show that at finite temperature there is an
additional single-magnon contribution to the scattering with a spectral weight
proportional to $T^3$. We also compute the leading corrections to the UCL
approximation and find them to be small, putting the UCL results on a solid
basis. All this univocally points to the conclusion that the observed low
temperature RIXS intensity in La$_2$CuO$_4$ is due to two-magnon scattering.


title: Higgs Amplitudes From Twistor Inspired Methods

abstract:
  We illustrate the use of new on-shell methods, 4-dimensional unitarity cuts
combined with on-shell recursions relations, by computing the
A_4^{(1)}(phi,1^-,2^-,3^+,4^+) amplitude in the large top mass limit where the
Higgs boson couples to gluons through an effective interaction.


title: Hawking Radiation from Non-Extremal D1-D5 Black Hole via Anomalies

abstract:
  We take the method of anomaly cancellation for the derivation of Hawking
radiation initiated by Robinson and Wilczek, and apply it to the non-extremal
five-dimensional D1-D5 black hole in string theory. The fluxes of the electric
charge flow and the energy-momentum tensor from the black hole are obtained.
They are shown to match exactly with those of the two-dimensional black body
radiation at the Hawking temperature.


title: Atmospheric dynamics and the mass loss process in red supergiant stars

abstract:
  Red supergiant stars represent a key phase in the evolution of massive stars.
Recent radiative hydrodynamic simulations suggest that their atmospheres may be
the location of large-scale convective motions. As supergiant convection is
expected to generate supersonic motions and shocks, we seek constraints on
these atmospheric motions and their possible relation with mass-loss rates. We
present high-resolution, visible spectroscopy of a sample of red supergiants
(spectral type M I) and analyse them with a tomographic technique. We observe
steep velocity gradients, characterising both upward and downward supersonic
motions, which are time variable on time scales of a few hundred days. These
convective motions will generate turbulent pressure, which will strongly
decrease the effective gravity. We suggest that this decrease, combined with
radiative pressure on molecular lines, initiate the mass loss in red supergiant
stars.


title: Eternal Inflation is "Expensive"

abstract:
  The discovery of the string theory landscape has recently brought attention
to the eternal nature of inflation. In contrast to the common belief that
eternal inflation may be a generic feature of most inflationary models, in this
note we argue that the suppressed amplitude of perturbations due to adiabatic
regularization, together with a fine-tuning constraint on the equation of state
of the rare inflating pockets with large fluctuations, render eternal inflation
expensive in energy and may make it unlikely to occur. The energy scales of the
eternally inflating pockets have to be very close to the transplanckian regime
in order to compensate for the suppression of regularized perturbations.


title: The mass and the coupling of the Dark Particle

abstract:
  We argue that Dark Matter can be described by an interacting field theory
with a mass parameter of the order of the proton mass and an interaction
coupling of the order of the QED coupling.


title: Forward stagewise regression and the monotone lasso

abstract:
  We consider the least angle regression and forward stagewise algorithms for
solving penalized least squares regression problems. In Efron, Hastie,
Johnstone & Tibshirani (2004) it is proved that the least angle regression
algorithm, with a small modification, solves the lasso regression problem. Here
we give an analogous result for incremental forward stagewise regression,
showing that it solves a version of the lasso problem that enforces
monotonicity. One consequence of this is as follows: while lasso makes optimal
progress in terms of reducing the residual sum-of-squares per unit increase in
$L_1$-norm of the coefficient $\beta$, forward stage-wise is optimal per unit
$L_1$ arc-length traveled along the coefficient path. We also study a condition
under which the coefficient paths of the lasso are monotone, and hence the
different algorithms coincide. Finally, we compare the lasso and forward
stagewise procedures in a simulation study involving a large number of
correlated predictors.


title: Roughness induced boundary slip in microchannel flows

abstract:
  Surface roughness becomes relevant if typical length scales of the system are
comparable to the scale of the variations as it is the case in microfluidic
setups. Here, an apparent boundary slip is often detected which can have its
origin in the assumption of perfectly smooth boundaries. We investigate the
problem by means of lattice Boltzmann (LB) simulations and introduce an
``effective no-slip plane'' at an intermediate position between peaks and
valleys of the surface. Our simulations show good agreement with analytical
results for sinusoidal boundaries, but can be extended to arbitrary geometries
and experimentally obtained surface data. We find that the detected apparent
slip is independent of the detailed boundary shape, but only given by the
distribution of surface heights. Further, we show that the slip diverges as the
amplitude of the roughness increases.


title: Pairing based cooling of Fermi gases

abstract:
  We propose a pairing-based method for cooling an atomic Fermi gas. A three
component (labels 1, 2, 3) mixture of Fermions is considered where the
components 1 and 2 interact and, for instance, form pairs whereas the component
3 is in the normal state. For cooling, the components 2 and 3 are coupled by an
electromagnetic field. Since the quasiparticle distributions in the paired and
in the normal states are different, the coupling leads to cooling of the normal
state even when initially $T_{paired}\geq T_{normal}$ (notation $T_S\geq T_N$).
The cooling efficiency is given by the pairing energy and by the linewidth of
the coupling field. No superfluidity is required: any type of pairing, or other
phenomenon that produces a suitable spectral density, is sufficient. In
principle, the paired state could be cooled as well but this requires
$T_N<T_S$. The method has a conceptual analogy to cooling based on
superconductor -- normal metal (SN) tunneling junctions. Main differences arise
from the exact momentum conservation in the case of the field-matter coupling
vs. non-conservation of momentum in the solid state tunneling process.
Moreover, the role of processes that relax the energy conservation requirement
in the tunneling, e.g. thermal fluctuations of an external reservoir, is now
played by the linewidth of the field. The proposed method should be
experimentally feasible due to its close connection to RF-spectroscopy of
ultracold gases which is already in use.


title:
Near infrared spectroscopic search for the close orbiting planet HD
  75289b

abstract:
  We present a search for the near infrared spectroscopic signature of the
close orbiting extrasolar giant planet HD 75289b. We obtained ~230 spectra in
the wavelength range 2.18 - 2.19 microns using the Phoenix spectrograph at
Gemini South. By considering the direct spectrum, derived from irradiated model
atmospheres, we search for the absorption profile signature present in the
combined star and planet light. Since the planetary spectrum is separated from
the stellar spectrum at most phases, we apply a phase dependent orbital model
and tomographic techniques to search for absorption signatures.
  Because the absorption signature lies buried in the noise of a single
exposure we apply a multiline deconvolution to the spectral lines available in
order to boost the effective S/N ratio of the data. The wavelength coverage of
80 angstroms is expected to contain ~100 planetary lines, enabling a mean line
with S/N ratio of ~800 to be achieved after deconvolution. We are nevertheless
unable to detect the presence of the planet in the data and carry out further
simulations to show that broader wavelength coverage should enable a planet
like HD 75289b to be detected with 99.9 per cent (4 sigma) confidence. We
investigate the sensitivity of our method and estimate detection tolerances for
mismatches between observed and model planetary atmospheres.


title: Flaming, bright galaxies along the filaments of A2744

abstract:
  The existence of a clumpy, large-scale filamentary structure is at the basis
of the current paradigm of cosmic formation and evolution of clusters. The
star-formation history of galaxies falling into a cluster is altered as a
result of the environmental stresses. We investigate the relation between
substructure and properties of the galaxy population in a 30'x30' region
centered on the massive merging cluster A2744 at z~0.3. Multi-object
spectroscopy at low resolution and BVR photometry are used to detect the
presence of substructure through a Dressler-Schectman analysis and the
photometric redshift technique, respectively. Galaxies at the same photometric
redshift of the cluster are divided into red and blue according to their
distribution in the B-R vs. R colour-magnitude diagram. We identify two
large-scale filaments associated with A2744. Along these filaments, the
blue-to-red galaxy number ratio increases together with the cluster-centric
distance but peaks slightly beyond the cluster virial radius. The filaments
host a population of bright, large (i.e. more luminous than R* for the main
body of the cluster and with angular sizes of 13-22 $h_{70}^{-1}$ kpc) blue
galaxies that is hardly found among galaxies lying in a neighbouring
low-density environment at the same redshift of the cluster. These results can
be interpreted as a manifestation of galaxy harassment.


title: Needlet algorithms for estimation in inverse problems

abstract:
  We provide a new algorithm for the treatment of inverse problems which
combines the traditional SVD inversion with an appropriate thresholding
technique in a well chosen new basis. Our goal is to devise an inversion
procedure which has the advantages of localization and multiscale analysis of
wavelet representations without losing the stability and computability of the
SVD decompositions. To this end we utilize the construction of localized frames
(termed "needlets") built upon the SVD bases. We consider two different
situations: the "wavelet" scenario, where the needlets are assumed to behave
similarly to true wavelets, and the "Jacobi-type" scenario, where we assume
that the properties of the frame truly depend on the SVD basis at hand (hence
on the operator). To illustrate each situation, we apply the estimation
algorithm respectively to the deconvolution problem and to the Wicksell
problem. In the latter case, where the SVD basis is a Jacobi polynomial basis,
we show that our scheme is capable of achieving rates of convergence which are
optimal in the $L_2$ case, we obtain interesting rates of convergence for other
$L_p$ norms which are new (to the best of our knowledge) in the literature, and
we also give a simulation study showing that the NEED-D estimator outperforms
other standard algorithms in almost all situations.


title: An analytic KAM-Theorem

abstract:
  We prove an analytic KAM-Theorem, which is used in [1], where the
differential part of KAM-theory is discussed. Related theorems on analytic
KAM-theory exist in the literature (e. g., among many others, [7], [8], [13]).
The aim of the theorem presented here is to provide exactly the estimates
needed in [1].


title:
Degenerate Series Representations of the $q$-Deformed Algebra ${\rm
  so}'_q(r,s)$

abstract:
  The q-deformed algebra ${\rm so}'_q(r,s)$ is a real form of the q-deformed
algebra $U'_q({\rm so}(n,\mathbb{C}))$, $n=r+s$, which differs from the quantum
algebra $U_q({\rm so}(n,\mathbb{C}))$ of Drinfeld and Jimbo. We study
representations of the most degenerate series of the algebra ${\rm
so}'_q(r,s)$. The formulas of action of operators of these representations upon
the basis corresponding to restriction of representations onto the subalgebra
${\rm so}'_q(r)\times {\rm so}'_q(s)$ are given. Most of these representations
are irreducible. Reducible representations appear under some conditions for the
parameters determining the representations. All irreducible constituents which
appear in reducible representations of the degenerate series are found. All
$*$-representations of ${\rm so}'_q(r,s)$ are separated in the set of
irreducible representations obtained in the paper.


title:
Charge current driven by spin dynamics in disordered Rashba spin-orbit
  system

abstract:
  Pumping of charge current by spin dynamics in the presence of the Rashba
spin-orbit interaction is theoretically studied. Considering disordered
electron, the exchange coupling and spin-orbit interactions are treated
perturbatively. It is found that dominant current induced by the spin dynamics
is interpreted as a consequence of the conversion from spin current via the
inverse spin Hall effect. We also found that the current has an additional
component from a fictitious conservative field. Results are applied to the case
of moving domain wall.


title:
A general framework for nonholonomic mechanics: Nonholonomic Systems on
  Lie affgebroids

abstract:
  This paper presents a geometric description of Lagrangian and Hamiltonian
systems on Lie affgebroids subject to affine nonholonomic constraints. We
define the notion of nonholonomically constrained system, and characterize
regularity conditions that guarantee that the dynamics of the system can be
obtained as a suitable projection of the unconstrained dynamics. It is shown
that one can define an almost aff-Poisson bracket on the constraint AV-bundle,
which plays a prominent role in the description of nonholonomic dynamics.
Moreover, these developments give a general description of nonholonomic systems
and the unified treatment permits to study nonholonomic systems after or before
reduction in the same framework. Also, it is not necessary to distinguish
between linear or affine constraints and the methods are valid for explicitly
time-dependent systems.


title:
Opaque Attack on Three-Party Quantum Secret Sharing Based on
  Entanglement

abstract:
  Security of the three-party quantum secret sharing (QSS) schemes based on
entanglement and a collective eavesdropping check is analyzed in the case of
considerable quantum channel losses. An opaque attack scheme is presented for
the dishonest agent to eavesdrop the message obtained by the other agent
freely, which reveals that these QSS schemes are insecure for transmission
efficiencies lower than 50%, especially when they are used to share an unknown
quantum state. Finally, we present a general way to improve the security of QSS
schemes for sharing not only a private key but also an unknown quantum state.


title:
Simulation of Laser Propagation in a Plasma with a Frequency Wave
  Equation

abstract:
  The aim of this work is to perform numerical simulations of the propagation
of a laser in a plasma. At each time step, one has to solve a Helmholtz
equation in a domain which consists in some hundreds of millions of cells. To
solve this huge linear system, one uses a iterative Krylov method with a
preconditioning by a separable matrix. The corresponding linear system is
solved with a block cyclic reduction method. Some enlightments on the parallel
implementation are also given. Lastly, numerical results are presented
including some features concerning the scalability of the numerical method on a
parallel architecture.


title:
Dynamic Clustering in Object-Oriented Databases: An Advocacy for
  Simplicity

abstract:
  We present in this paper three dynamic clustering techniques for
Object-Oriented Databases (OODBs). The first two, Dynamic, Statistical &
Tunable Clustering (DSTC) and StatClust, exploit both comprehensive usage
statistics and the inter-object reference graph. They are quite elaborate.
However, they are also complex to implement and induce a high overhead. The
third clustering technique, called Detection & Reclustering of Objects (DRO),
is based on the same principles, but is much simpler to implement. These three
clustering algorithm have been implemented in the Texas persistent object store
and compared in terms of clustering efficiency (i.e., overall performance
increase) and overhead using the Object Clustering Benchmark (OCB). The results
obtained showed that DRO induced a lighter overhead while still achieving
better overall performance.


title: Proton spin polarizabilities from polarized Compton scattering

abstract:
  Polarized Compton scattering off the proton is studied within the framework
of subtracted dispersion relations for photon energies up to 300 MeV. As a
guideline for forthcoming experiments, we focus the attention on the role of
the proton's spin polarizabilities and investigate the most favorable
conditions to extract them with a minimum of model dependence. We conclude that
a complete separation of the four spin polarizabilities is possible, at photon
energies between threshold and the $\Delta(1232)$ region, provided one can
achieve polarization measurements with an accuracy of a few percent.


title: Lattice renormalisation of O(a) improved heavy-light operators

abstract:
  The analytical expressions and the numerical values of the renormalisation
constants of ${\cal O}(a)$ improved static-light currents are given at one-loop
order of perturbation theory in the framework of Heavy Quark Effective Theory:
the static quark is described by the HYP action and the light quark is
described either with the Clover or the Neuberger action. These factors are
relevant to extract from a lattice computation the decay constants $f_B$,
$f_{B_S}$ and the set of bag parameters $B_i$ associated with $B-\bar{B}$
mixing phenomenology in the Standard Model and beyond.


title: Projecting Massive Scalar Fields to Null Infinity

abstract:
  It is known that, in an asymptotically flat spacetime, null infinity cannot
act as an initial-value surface for massive real scalar fields. Exploiting
tools proper of harmonic analysis on hyperboloids and global norm estimates for
the wave operator, we show that it is possible to circumvent such obstruction
at least in Minkowski spacetime. Hence we project norm-finite solutions of the
Klein-Gordon equation of motion in data on null infinity and, eventually, we
interpret them in terms of boundary free field theory.


title:
Rates and Characteristics of Intermediate Mass Ratio Inspirals
  Detectable by Advanced LIGO

abstract:
  Gravitational waves (GWs) from the inspiral of a neutron star (NS) or
stellar-mass black hole (BH) into an intermediate-mass black hole (IMBH) with
mass between ~50 and ~350 solar masses may be detectable by the planned
advanced generation of ground-based GW interferometers. Such intermediate mass
ratio inspirals (IMRIs) are most likely to be found in globular clusters. We
analyze four possible IMRI formation mechanisms: (1) hardening of an NS-IMBH or
BH-IMBH binary via three-body interactions, (2) hardening via Kozai resonance
in a hierarchical triple system, (3) direct capture, and (4) inspiral of a
compact object from a tidally captured main-sequence star; we also discuss
tidal effects when the inspiraling object is an NS. For each mechanism we
predict the typical eccentricities of the resulting IMRIs. We find that IMRIs
will have largely circularized by the time they enter the sensitivity band of
ground-based detectors. Hardening of a binary via three-body interactions,
which is likely to be the dominant mechanism for IMRI formation, yields
eccentricities under 10^-4 when the GW frequency reaches 10 Hz. Even among
IMRIs formed via direct captures, which can have the highest eccentricities,
around 90% will circularize to eccentricities under 0.1 before the GW frequency
reaches 10 Hz. We estimate the rate of IMRI coalescences in globular clusters
and the sensitivity of a network of three Advanced LIGO detectors to the
resulting GWs. We show that this detector network may see up to tens of IMRIs
per year, although rates of one to a few per year may be more plausible. We
also estimate the loss in signal-to-noise ratio that will result from using
circular IMRI templates for data analysis and find that, for the eccentricities
we expect, this loss is negligible.


title:
Inverse-free Berlekamp-Massey-Sakata Algorithm and Small Decoders for
  Algebraic-Geometric Codes

abstract:
  This paper proposes a novel algorithm for finding error-locators of
algebraic-geometric codes that can eliminate the division-calculations of
finite fields from the Berlekamp-Massey-Sakata algorithm. This inverse-free
algorithm provides full performance in correcting a certain class of errors,
generic errors, which includes most errors, and can decode codes on algebraic
curves without the determination of unknown syndromes. Moreover, we propose
three different kinds of architectures that our algorithm can be applied to,
and we represent the control operation of shift-registers and switches at each
clock-timing with numerical simulations. We estimate the performance in
comparison of the total running time and the numbers of multipliers and
shift-registers in three architectures with those of the conventional ones for
codes on algebraic curves.


title: The Wide Field Spectrograph (WiFeS)

abstract:
  This paper describes the Wide Field Spectrograph (WiFeS) under construction
at the Research School of Astronomy and Astrophysics (RSAA) of the Australian
National University (ANU) for the ANU 2.3m telescope at the Siding Spring
Observatory. WiFeS is a powerful integral field, double-beam, concentric,
image-slicing spectrograph designed to deliver excellent thoughput, wavelength
stability, spectrophotometric performance and superb image quality along with
wide spectral coverage throughout the 320-950 nm wavelength region. It provides
a 25x38 arcsec. field with 0.5 arcsec. sampling along each of twenty five 38X1
arcsec slitlets. The output format is optimized to match the 4096x4096 pixel
CCD detectors in each of two cameras individually optimized for the blue and
the red ends of the spectrum, respectively. A process of "interleaved
nod-and-shuffle" will be applied to permit quantum noise-limited sky
subtraction. Using VPH gratings, spectral resolutions of 3000 and 7000 are
provided. The full spectral range is covered in a single exposure at R=3000,
and in two exposures in the R=7000 mode. The use of transmissive coated optics,
VPH gratings and optimized mirror coatings ensures a throughput (including
telescope atmosphere and detector) > 30% over a wide spectral range. The
concentric image-slicer design ensures an excellent and uniform image quality
across the full field. To maximize scientific return, the whole instrument is
configured for remote observing, pipeline data reduction, and the accumulation
of calibration image libraries.


title:
A new Cement to Glue non-conforming Grids with Robin interface
  conditions: the finite element case

abstract:
  We design and analyze a new non-conforming domain decomposition method based
on Schwarz type approaches that allows for the use of Robin interface
conditions on non-conforming grids. The method is proven to be well posed, and
the iterative solver to converge. The error analysis is performed in 2D
piecewise polynomials of low and high order and extended in 3D for $P_1$
elements. Numerical results in 2D illustrate the new method.


title:
Signatures of Random Matrix Theory in the Discrete Energy Spectra of
  Subnanosize Metallic Clusters

abstract:
  Lead clusters deposited on Si(111) substrates have been studied at low
temperatures using scanning tunneling microscopy and spectroscopy. The
current-voltage characteristics exhibit current peaks that are irregularly
spaced and varied in height. The statistics of the distribution of peak heights
and spacings are in agreement with random matrix theory for several clusters.
The distributions have also been studied as a function of cluster shape.


title:
PArthENoPE: Public Algorithm Evaluating the Nucleosynthesis of
  Primordial Elements

abstract:
  We describe a program for computing the abundances of light elements produced
during Big Bang Nucleosynthesis which is publicly available at
http://parthenope.na.infn.it/. Starting from nuclear statistical equilibrium
conditions the program solves the set of coupled ordinary differential
equations, follows the departure from chemical equilibrium of nuclear species,
and determines their asymptotic abundances as function of several input
cosmological parameters as the baryon density, the number of effective
neutrino, the value of cosmological constant and the neutrino chemical
potential. The program requires commercial NAG library routines.


title: Properties of B\"or\"oczki tilings in high dimensional hyperbolic spaces

abstract:
  We consider families of B\"or\"oczky tilings in hyperbolic space in arbitrary
dimension, study some basic properties and classify all possible symmetries. In
particular, it is shown that these tilings are non-crystallographic, and that
there are uncountably many tilings with a fixed prototile.


title: Entropy scaling and simulability by Matrix Product States

abstract:
  We investigate the relation between the scaling of block entropies and the
efficient simulability by Matrix Product States (MPS), and clarify the
connection both for von Neumann and Renyi entropies (see Table I). Most
notably, even states obeying a strict area law for the von Neumann entropy are
not necessarily approximable by MPS. We apply these results to illustrate that
quantum computers might outperform classical computers in simulating the time
evolution of quantum systems, even for completely translational invariant
systems subject to a time independent Hamiltonian.


title:
The Euler characteristic of local systems on the moduli of curves and
  abelian varieties of genus three

abstract:
  We show how to calculate the Euler characteristic of a local system
associated to an irreducible representation of the symplectic group of genus 3
on the moduli space of curves of genus 3 and the moduli space of principally
polarized abelian varieties of dimension 3.


title: Gauge coupling unification and light Exotica in String Theory

abstract:
  In this letter we consider the consequences for the LHC of light vector-like
exotica with fractional electric charge. It is shown that such states are found
in orbifold constructions of the heterotic string. Moreover, these exotica are
consistent with gauge coupling unification at one loop, even though they do not
come in complete multiplets of SU(5).


title:
Theory of Nonlinear Harmonic Generation in Free-Electron Lasers with
  Helical Wigglers

abstract:
  Coherent Harmonic Generation (CHG), and in particular Nonlinear Harmonic
Generation (NHG), is of importance for both short wavelength Free-Electron
Lasers (FELs), in relation with the achievement of shorter wavelengths with a
fixed electron-beam energy, and high-average power FEL resonators, in relation
with destructive effects of higher harmonics radiation on mirrors. In this
paper we present a treatment of NHG from helical wigglers with particular
emphasis on the second harmonic. Our study is based on an exact analytical
solution of Maxwell's equations, derived with the help of a Green's function
method. In particular, we demonstrate that nonlinear harmonic generation (NHG)
from helical wigglers vanishes on axis. Our conclusion is in open contrast with
results in literature, that include a kinematical mistake in the description of
the electron motion.


title:
Higher Order Asymptotic Formulas for Traces of Toeplitz Matrices with
  Symbols in H\"older-Zygmund Spaces

abstract:
  We prove a higher order asymptotic formula for traces of finite block
Toeplitz matrices with symbols belonging to H\"older-Zygmund spaces. The
remainder in this formula goes to zero very rapidly for very smooth symbols.
This formula refine previous asymptotic trace formulas by Szeg\"o and Widom and
complement higher order asymptotic formulas for determinants of finite block
Toeplitz matrices due to B\"ottcher and Silbermann.


title: Measure of the Julia Set of the Feigenbaum map with infinite criticality

abstract:
  We consider fixed points of the Feigenbaum (periodic-doubling) operator whose
orders tend to infinity. It is known that the hyperbolic dimension of their
Julia sets go to 2. We prove that the Lebesgue measure of these Julia sets tend
to zero. An important part of the proof consists in applying martingale theory
to a stochastic process with non-integrable increments.


title: J1128+592: a highly variable IDV source

abstract:
  Short time-scale radio variations of compact extragalactic radio quasars and
blazars known as IntraDay Variability (IDV) can be explained in at least some
sources as a propagation effect; the variations are interpreted as
scintillation of radio waves in the turbulent interstellar medium of the Milky
Way. One of the most convincing observational arguments in favor of a
propagation-induced variability scenario is the observed annual modulation in
the characteristic time scale of the variation due to the Earth's orbital
motion. So far there are only two sources known with a well-constrained
seasonal cycle. Annual modulation has been proposed for a few other less
well-documented objects. However, for some other IDV sources source-intrinsic
structural variations which cause drastic changes in the variability time scale
were also suggested. J1128+592 is a recently discovered, highly variable IDV
source. Previous, densely time-sampled flux-density measurements with the
Effelsberg 100-m radio telescope (Germany) and the Urumqi 25-m radio telescope
(China), strongly indicate an annual modulation of the time scale. The most
recent 4 observations in 2006/7, however, do not fit well to the annual
modulation model proposed before. In this paper, we investigate a possible
explanation of this discrepancy.


title: Charge transfer mechanism and Tc(x) dependence in Y0.8(Ca)0.2Ba2Cu3O6+x

abstract:
  We propose a model for charge transfer mechanism in Y0.8(Ca)0.2Ba2Cu3O6+x to
count hole doping of CuO2 planes and x dependence of critical transition
temperature T_c. It is assumed the total number of doped holes in the planes is
sum of holes that are introduced through two separate channels: substitution of
Y3+ by Ca2+ and from CuO chains that are longer than a minimal (critical)
length l_min needed for charge transfer to take place. The T_c(x) dependence is
obtained by combining calculated x dependence of doping, p(x), and universal
T_c versus p relation. Although calculated T_c(x) dependences for l_min=3 and
l_min=4 both remarkably correlate to the experimental T_c(x), we argue that the
value l_min=4 gives a reasonable overall agreement.


title: Nonextensive effects on the relativistic nuclear equation of state

abstract:
  The Walecka many-body field theory is investigated in the context of quantum
nonextensive statistical mechanics, characterized by a dimensionless parameter
$q$. We consider nuclear matter described statistically by a power-law
distribution which generalizes the standard Fermi-Dirac distribution ($q = 1$).
We show that the scalar and vector meson fields become more intense due to the
nonextensive effects ($q \neq 1$). From a numerical treatment, we also show
that as the nonextensive parameter $q$ increases, the nucleon effective mass
diminishes and the equation of state becomes stiffer. Finally, the usual
Maxwell construction seems not to be necessary for isotherms with temperatures
in the range 14 Mev$<k_BT<$20 MeV.


title: Planck Scale Unification in a Supersymmetric Standard Model

abstract:
  We show how gauge coupling unification near the Planck scale $M_P\sim
10^{19}$ GeV can be achieved in the framework of supersymmetry, facilitating a
full unification of all forces with gravity. Below the conventional GUT scale
$M_{GUT}\sim 10^{16}$ GeV physics is described by a Supersymmetric Standard
Model whose particle content is that of three complete $\mathbf{27}$
representations of the gauge group $E_6$. Above the conventional GUT scale the
gauge group corresponds to a left-right symmetric Supersymmetric Pati-Salam
model, which may be regarded as a ``surrogate SUSY GUT'' with all the nice
features of SO(10) but without proton decay or doublet-triplet splitting
problems. At the TeV scale the extra exotic states may be discovered at the
LHC, providing an observable footprint of an underlying $E_6$ gauge group
broken at the Planck scale. Assuming an additional low energy $U(1)_X$ gauge
group, identified as a non-trivial combination of diagonal $E_6$ generators,
the $\mu$ problem of the MSSM can be resolved.


title: On two conjectures for curves on $K3$ surfaces

abstract:
  We prove that the gonality among the smooth curves in a complete linear
system on a $K3$ surface is constant except for the Donagi-Morrison example.
This was proved by Ciliberto and Pareschi under the additional condition that
the linear system is ample.
  As a consequence we prove that exceptional curves on $K3$ surfaces satisfy
the Eisenbud-Lange-Martens-Schreyer conjecture and explicitly describe such
curves. They turn out to be natural extensions of the
Eisenbud-Lange-Martens-Schreyer examples of exceptional curves on $K3$
surfaces.


title: Gluon scattering amplitudes at strong coupling

abstract:
  We describe how to compute planar gluon scattering amplitudes at strong
coupling in N=4 super Yang Mills by using the gauge/string duality. The
computation boils down to finding a certain classical string configuration
whose boundary conditions are determined by the gluon momenta. The results are
infrared divergent. We introduce the gravity version of dimensional
regularization to define finite quantities. The leading and subleading IR
divergencies are characterized by two functions of the coupling that we compute
at strong coupling. We compute also the full finite form for the four point
amplitude and we find agreement with a recent ansatz by Bern, Dixon and
Smirnov.


title:
Mod\'elisations prospectives de l'occupation du sol. Le cas d'une
  montagne m\'editerran\'eenne

abstract:
  The authors apply three methods of prospective modelling to high resolution
georeferenced land cover data in a Mediterranean mountain area: GIS approach,
non linear parametric model and neuronal network. Land cover prediction to the
latest known date is used to validate the models. In the frame of
spatial-temporal dynamics in open systems results are encouraging and
comparable. Correct prediction scores are about 73 %. The results analysis
focuses on geographic location, land cover categories and parametric distance
to reality of the residues. Crossing the three models show the high degree of
convergence and a relative similitude of the results obtained by the two
statistic approaches compared to the GIS supervised model. Steps under work are
the application of the models to other test areas and the identification of
respective advantages to develop an integrated model.


title:
Thermodynamics of an Accretion Disk Annulus with Comparable Radiation
  and Gas Pressure

abstract:
  We explore the thermodynamic and global structural properties of a local
patch of an accretion disk whose parameters were chosen so that radiation
pressure and gas pressure would be comparable in magnitude. Heating, radiative
transport, and cooling are computed self-consistently with the structure by
solving the equations of radiation MHD in the shearing-box approximation. Using
a fully 3-d and energy-conserving code, we compute the structure and energy
balance of this disk segment over a span of more than forty cooling times. As
is also true when gas pressure dominates, the disk's upper atmosphere is
magnetically-supported. However, unlike the gas-dominated case, no steady-state
is reached; instead, the total (i.e., radiation plus gas) energy content
fluctuates by factors of 3--4 over timescales of several tens of orbits, with
no secular trend. Because the radiation pressure varies much more than the gas
pressure, the ratio of radiation pressure to gas pressure varies over the
approximate range 0.5--2. The volume-integrated dissipation rate generally
increases with increasing total energy, but the mean trend is somewhat slower
than linear, and the instantaneous dissipation rate is often a factor of two
larger or smaller than the mean for that total energy level. Locally, the
dissipation rate per unit volume scales approximately in proportion to the
current density; the time-average dissipation rate per unit mass is
proportional to m^{-1/2}, where m is the horizontally-averaged mass column
density to the nearer of the top or bottom surface. As in our earlier study of
a gas-dominated shearing-box, we find that energy transport is completely
dominated by radiative diffusion, with Poynting flux carrying less than 1% of
the energy lost from the box.


title: Search for stopped gluinos from p-pbar collisions at sqrt(s)=1.96 TeV

abstract:
  Long-lived, heavy particles are predicted in a number of models beyond the
standard model of particle physics. We present the first direct search for such
particles' decays, occurring up to 100 hours after their production and not
synchronized with an accelerator bunch crossing. We apply the analysis to the
gluino (~g), predicted in split supersymmetry, which after hadronization can
become charged and lose enough momentum through ionization to come to rest in
dense particle detectors. Approximately 410 pb^-1 of p-pbar collisions at 1.96
TeV collected with the D0 detector during Run II of the Fermilab Tevatron
collider are analyzed in search of such ``stopped gluinos'' decaying into a
gluon and a neutralino (~X_0), reconstructed as a jet and missing energy. No
excess is observed above background, and limits are placed on the (gluino cross
section) x (probability to stop) x BR(~g -> g ~X_0) as a function of the gluino
and ~X_0 masses, for gluino lifetimes from 30 $\mu$s -- 100 hours.


title:
Mass and Free energy in Thermodynamics of Squashed Kaluza-Klein Black
  Holes

abstract:
  The Abbott-Deser mass, the Hamiltonian and the Komar mass of the
5-dimensional Kaluza-Klein black hole with squashed horizons take different
values. Introducing a new couple of thermodynamic variables for the Komar mass,
we show that each mass can be interpreted as a thermodynamic potential with its
own natural variables, i.e. all masses are related to each other by the
Legendre transformations. It is found that the new variables and the
gravitational tension represent the squashing of the outer horizon.


title:
Mass limits for scalar and gauge leptoquarks from $ K_L^0 \to e^{\mp}
  \mu^{\pm}, B^0 \to e^{\mp} \tau^{\pm} $ decays

abstract:
  The contributions of scalar and gauge leptoquarks into widths of $K^0_L \to
e^{\mp} \mu^{\pm}$, $B^0 \to e^{\mp} \tau^{\pm}$ decays are calculated in the
models with the vectorlike and chiral four color symmetry and with the Higgs
mechanism of the quark-lepton mass splitting. From the current data on $K^0_L$
and $B^0$ decays the mass limits for scalar and chiral leptoquarks and the
updated vector leptoquark mass limits are obtained. It is shown that unlike the
gauge leptoquarks the scalar leptoquark mass limits are weak, of order or below
their direct mass limits. The search for such scalar leptoquarks at LHC and the
further search for leptonic decays $ B^0 \to l^+_i l^-_j $ are of interest.


title:
The Crossover from Impurity to Valence Band in Diluted Magnetic
  Semiconductors: The Role of the Coulomb Attraction by Acceptor

abstract:
  The crossover between an impurity band (IB) and a valence band (VB) regime as
a function of the magnetic impurity concentration in models for diluted
magnetic semiconductors (DMS) is studied systematically by taking into
consideration the Coulomb attraction between the carriers and the magnetic
impurities. The density of states and the ferromagnetic transition temperature
of a Spin-Fermion model applied to DMS are evaluated using Dynamical Mean-Field
Theory (DMFT) and Monte Carlo (MC) calculations. It is shown that the addition
of a square-well-like attractive potential can generate an IB at small enough
Mn doping $x$ for values of the $p-d$ exchange $J$ that are not strong enough
to generate one by themselves. We observe that the IB merges with the VB when
$x >= x_c$ where $x_c$ is a function of $J$ and the Coulomb attraction strength
$V$. Using MC calculations, we demonstrate that the range of the Coulomb
attraction plays an important role. While the on-site attraction, that has been
used in previous numerical simulations, effectively renormalizes $J$ for all
values of $x$, an unphysical result, a nearest-neighbor range attraction
renormalizes $J$ only at very low dopings, i.e., until the bound holes wave
functions start to overlap. Thus, our results indicate that the Coulomb
attraction can be neglected to study Mn doped GaSb, GaAs, and GaP in the
relevant doping regimes, but it should be included in the case of Mn doped GaN
that is expected to be in the IB regime.


title: The Level-0 Muon Trigger for the LHCb Experiment

abstract:
  A very compact architecture has been developed for the first level Muon
Trigger of the LHCb experiment that processes 40 millions of proton-proton
collisions per second. For each collision, it receives 3.2 kBytes of data and
it finds straight tracks within a 1.2 microseconds latency. The trigger
implementation is massively parallel, pipelined and fully synchronous with the
LHC clock. It relies on 248 high density Field Programable Gate arrays and on
the massive use of multigigabit serial link transceivers embedded inside FPGAs.


title:
Resonant forcing of select degrees of freedom of multidimensional
  chaotic map dynamics

abstract:
  We study resonances of multidimensional chaotic map dynamics. We use the
calculus of variations to determine the additive forcing function that induces
the largest response, that is, the greatest deviation from the unperturbed
dynamics. We include the additional constraint that only select degrees of
freedom be forced, corresponding to a very general class of problems in which
not all of the degrees of freedom in an experimental system are accessible to
forcing. We find that certain Lagrange multipliers take on a fundamental
physical role as the efficiency of the forcing function and the effective
forcing experienced by the degrees of freedom which are not forced directly.
Furthermore, we find that the product of the displacement of nearby
trajectories and the effective total forcing function is a conserved quantity.
We demonstrate the efficacy of this methodology with several examples.


title:
Two-dimensional transport and transfer of a single atomic qubit in
  optical tweezers

abstract:
  Quantum computers have the capability of out-performing their classical
counterparts for certain computational problems. Several scalable quantum
computing architectures have been proposed. An attractive architecture is a
large set of physically independant qubits, arranged in three spatial regions
where (i) the initialized qubits are stored in a register, (ii) two qubits are
brought together to realize a gate, and (iii) the readout of the qubits is
performed. For a neutral atom-based architecture, a natural way to connect
these regions is to use optical tweezers to move qubits within the system. In
this letter we demonstrate the coherent transport of a qubit, encoded on an
atom trapped in a sub-micron tweezer, over a distance typical of the separation
between atoms in an array of optical traps. Furthermore, we transfer a qubit
between two tweezers, and show that this manipulation also preserves the
coherence of the qubit.


title: Information flow and optimization in transcriptional control

abstract:
  In the simplest view of transcriptional regulation, the expression of a gene
is turned on or off by changes in the concentration of a transcription factor
(TF). We use recent data on noise levels in gene expression to show that it
should be possible to transmit much more than just one regulatory bit.
Realizing this optimal information capacity would require that the dynamic
range of TF concentrations used by the cell, the input/output relation of the
regulatory module, and the noise levels of binding and transcription satisfy
certain matching relations. This parameter-free prediction is in good agreement
with recent experiments on the Bicoid/Hunchback system in the early Drosophila
embryo, and this system achieves ~90% of its theoretical maximum information
transmission.


title:
Surface Structure in an Accretion Disk Annulus with Comparable Radiation
  and Gas Pressure

abstract:
  We have employed a 3-d energy-conserving radiation MHD code to simulate the
vertical structure and thermodynamics of a shearing box whose parameters were
chosen so that the radiation and gas pressures would be comparable. The upper
layers of this disk segment are magnetically-dominated, creating conditions
appropriate for both photon bubble and Parker instabilities. We find little
evidence for photon bubbles, even though the simulation has enough spatial
resolution to see them and their predicted growth rates are high. On the other
hand, there is strong evidence for Parker instabilities, and they appear to
dominate the evolution of the magnetically supported surface layers. The disk
photosphere is complex, with large density inhomogeneities at both the
scattering and effective (thermalization) photospheres of the evolving
horizontally-averaged structure. Both the dominant magnetic support and the
inhomogeneities are likely to have strong effects on the spectrum and
polarization of thermal photons emerging from the disk atmosphere. The
inhomogeneities are also large enough to affect models of reflection spectra
from the atmospheres of accretion disks.


title: WDM and Directed Star Arboricity

abstract:
  A digraph is $m$-labelled if every arc is labelled by an integer in $\{1,
\dots,m\}$. Motivated by wavelength assignment for multicasts in optical
networks, we introduce and study $n$-fibre colourings of labelled digraphs.
These are colourings of the arcs of $D$ such that at each vertex $v$, and for
each colour $\alpha$, $in(v,\alpha)+out(v,\alpha)\leq n$ with $in(v,\alpha)$
the number of arcs coloured $\alpha$ entering $v$ and $out(v,\alpha)$ the
number of labels $l$ such that there is at least one arc of label $l$ leaving
$v$ and coloured with $\alpha$. The problem is to find the minimum number of
colours $\lambda_n(D)$ such that the $m$-labelled digraph $D$ has an $n$-fibre
colouring. In the particular case when $D$ is $1$-labelled, $\lambda_1(D)$ is
called the directed star arboricity of $D$, and is denoted by $dst(D)$. We
first show that $dst(D)\leq 2\Delta^-(D)+1$, and conjecture that if
$\Delta^-(D)\geq 2$, then $dst(D)\leq 2\Delta^-(D)$. We also prove that for a
subcubic digraph $D$, then $dst(D)\leq 3$, and that if $\Delta^+(D),
\Delta^-(D)\leq 2$, then $dst(D)\leq 4$. Finally, we study
$\lambda_n(m,k)=\max\{\lambda_n(D) \tq D \mbox{is $m$-labelled} \et
\Delta^-(D)\leq k\}$. We show that if $m\geq n$, then $\ds
\left\lceil\frac{m}{n}\left\lceil \frac{k}{n}\right\rceil + \frac{k}{n}
\right\rceil\leq \lambda_n(m,k) \leq\left\lceil\frac{m}{n}\left\lceil
\frac{k}{n}\right\rceil + \frac{k}{n} \right\rceil + C \frac{m^2\log k}{n}$ for
some constant $C$. We conjecture that the lower bound should be the right value
of $\lambda_n(m,k)$.


title: Coherent states for Hamiltonians generated by supersymmetry

abstract:
  Coherent states are derived for one-dimensional systems generated by
supersymmetry from an initial Hamiltonian with a purely discrete spectrum for
which the levels depend analytically on their subindex. It is shown that the
algebra of the initial system is inherited by its SUSY partners in the subspace
associated to the isospectral part or the spectrum. The technique is applied to
the harmonic oscillator, infinite well and trigonometric Poeschl-Teller
potentials.


title: Revisiting the one-dimensional diffusive contact process

abstract:
  In this work we study the one-dimensional contact process with diffusion
using two different approaches to research the critical properties of this
model: the supercritical series expansions and finite-size exact solutions.
With special emphasis we look to the multicritical point and its crossover
exponent that characterizes the passage between DP and mean-field critical
properties. This crossover occurs in the limit of infinite diffusion rate and
our results pointed $\phi=4$ as the better estimate for the crossover exponent
in agreement with computational simulations.


title: Decomposition of spaces of distributions induced by Hermite expansions

abstract:
  Decomposition systems with rapidly decaying elements (needlets) based on
Hermite functions are introduced and explored. It is proved that the
Triebel-Lizorkin and Besov spaces on $\R^d$ induced by Hermite expansions can
be characterized in terms of the needlet coefficients. It is also shown that
the Hermite Triebel-Lizorkin and Besov spaces are, in general, different from
the respective classical spaces.


title: Dark energy, cosmological constant and neutrino mixing

abstract:
  The today estimated value of dark energy can be achieved by the vacuum
condensate induced by neutrino mixing phenomenon. Such a tiny value is
recovered for a cut-off of the order of Planck scale and it is linked to the
sub eV neutrino mass scale. Contributions to dark energy from auxiliary fields
or mechanisms are not necessary in this approach.


title:
Experimental Demonstration of Compensation of Beam-Beam Effects by
  Electron Lenses

abstract:
  We report the first experimental demonstration of compensation of beam-beam
interaction effects in high-energy particle collider by using space-charge
forces of a low-energy electron beam. In our experiments, an electron lens, a
novel instrument developed for the beam-beam compensation, was set on a 980-GeV
proton bunch in the Tevatron proton-antiproton collider. The proton bunch
losses due to its interaction with antiproton beam were reduced by a factor of
2 when the electron lens was operating. We describe the principle of electron
lens operation and present experimental results.


title: The Four-Loop Dressing Phase of N=4 SYM

abstract:
  We compute the dilatation generator in the su(2) sector of planar N=4 super
Yang-Mills theory at four-loops. We use the known world-sheet scattering matrix
to constrain the structure of the generator. The remaining few coefficients can
be computed directly from Feynman diagrams. This allows us to confirm previous
conjectures for the leading contribution to the dressing phase which is
proportional to zeta(3).


title: Nonlocality of a single particle

abstract:
  There has been a great deal of debate surrounding the issue of whether it is
possible for a single photon to exhibit nonlocality. A number of schemes have
been proposed that claim to demonstrate this effect, but each has been met with
significant opposition. The objections hinge largely on the fact that these
schemes use unobservable initial states and so, it is claimed, they do not
represent experiments that could actually be performed. Here we show how it is
possible to overcome these objections by presenting an experimentally feasible
scheme that uses realistic initial states. Furthermore, all the techniques
required for photons are equally applicable to atoms. It should, therefore,
also be possible to use this scheme to verify the nonlocality of a single
massive particle.


title: Characterizing Potentials by a Generalized Boltzmann Factor

abstract:
  Based on the concept of a nonequilibrium steady state, we present a novel
method to experimentally determine energy landscapes acting on colloidal
systems. By measuring the stationary probability distribution and the current
in the system, we explore potential landscapes with barriers up to several
hundred $\kT$. As an illustration, we use this approach to measure the
effective diffusion coefficient of a colloidal particle moving in a tilted
potential.


title:
Distribution of Entropy Production for a Colloidal Particle in a
  Nonequilibrium Steady State

abstract:
  For a colloidal particle driven by a constant force across a periodic
potential, we investigate the distribution of entropy production both
experimentally and theoretically. For short trajectories, the fluctuation
theorem holds experimentally. The mean entropy production rate shows two
regimes as a function of the applied force. Theoretically, both mean and
variance of the pronounced non-Gaussian distribution can be obtained from a
differential equation in good agreement with the experimental data.


title: The order of the largest complete minor in a random graph

abstract:
  Let ccl(G) denote the order of the largest complete minor in a graph G (also
called the contraction clique number) and let G(n,p) denote a random graph on n
vertices with edge probability p. Bollobas, Catlin and Erdos asymptotically
determined ccl(G (n,p)) when p is a constant. Luczak, Pittel and Wierman gave
bounds on ccl(G(n,p)) when p is very close to 1/n, i.e. inside the phase
transition. Extending the results of Bollobas, Catlin and Erdos, we determine
ccl(G(n,p)) quite tightly, for p>C/n where C is a large constant. If p=C/n, for
an arbitrary constant C>1, then we show that asymptotically almost surely ccl(G
(n,p)) is of order square-root of n. This answers a question of Krivelevich and
Sudakov.


title:
Optimal Delay-Throughput Trade-offs in Mobile Ad-Hoc Networks: Hybrid
  Random Walk and One-Dimensional Mobility Models

abstract:
  Optimal delay-throughput trade-offs for two-dimensional i.i.d mobility models
have been established in [23], where we showed that the optimal trade-offs can
be achieved using rate-less codes when the required delay guarantees are
sufficient large. In this paper, we extend the results to other mobility models
including two-dimensional hybrid random walk model, one-dimensional i.i.d.
mobility model and one-dimensional hybrid random walk model. We consider both
fast mobiles and slow mobiles, and establish the optimal delay-throughput
trade-offs under some conditions. Joint coding-scheduling algorithms are also
proposed to achieve the optimal trade-offs.


title: Non-Abelian Discrete Flavor Symmetries

abstract:
  This is an incomplete survey of some non-Abelian discrete symmetries which
have been used recently in attempts to understand the flavor structure of
leptons and quarks. To support such symmetries, new scalar particles are
required. In some models, they are very massive, in which case there may not be
much of a trace of their existence at the TeV scale. In other models, they are
themselves at the TeV scale, in which case there is a reasonable chance for
them to be revealed at the LHC (Large Hadron Collider) at CERN.