title:
Operator algebra of foliations with projectively invariant transverse
  measure

abstract:
  We study the structure of operator algebras associated with the foliations
which have projectively invariant measures. When a certain ergodicity condition
on the measure preserving holonomies holds, the lack of holonomy invariant
transverse measure can be established in terms of a cyclic cohomology class
associated with the transverse fundamental cocycle and the modular automorphism
group.


title: Magnetic Confinement by Alfven Carpets

abstract:
  A "carpet" of torsional Alfven waves, resonantly excited in an annulus inside
a toroidal conducting vessel, could maintain magnetized plasma inside of the
annulus against the inherent outward expansion. Such toroidal magnetic
confinement for fusion could present some advantages over conventional
tokamaks. The idea could also be used to stabilize interchange and ballooning
modes in tokamaks and other interchange-limited fusion devices.


title:
Analysis of Lepton Flavor Violating \tau^\pm \to \mu^\pm \mu^\pm \mu^\mp
  Decays

abstract:
  Supposing only Lorentz and the gauge invariances of the Lagrangian, we derive
energy and angular distributions for $\tau^\pm \to \mu^\pm \mu^\pm \mu^\mp$
lepton flavor violating decay process. Using these results, we discuss methods
to determine the parameters associated with the lepton flavor violating
interactions.


title: On Moduli Spaces for Abelian Categories

abstract:
  We show that if A is an abelian category satisfying certain mild conditions,
then one can introduce the concept of a moduli space of (semi)stable objects
which has the structure of a projective algebraic variety. This idea is applied
to several important abelian categories in representation theory, like highest
weight categories.


title:
On the viability of the shearing box approximation for numerical studies
  of MHD turbulence in accretion disks

abstract:
  Most of our knowledge on the nonlinear development of the magneto-rotational
instability (MRI) relies on the results of numerical simulations employing the
shearing box (SB) approximation. A number of difficulties arising from this
approach have recently been pointed out in the literature. We thoroughly
examine the effects of the assumptions made and numerical techniques employed
in SB simulations. This is done in order to clarify and gain better
understanding of those difficulties as well as of a number of additional
serious problems, raised here for the first time, and of their impact on the
results. Analytical derivations and estimates as well as comparative analysis
to methods used in the numerical study of turbulence are used. Numerical
experiments are performed to support some of our claims and conjectures. The
following problems, arising from the (virtually exclusive) use of the SB
simulations as a tool for the understanding and quantification of the nonlinear
MRI development in disks, are analyzed and discussed: (i) inconsistencies in
the application of the SB approximation itself; (ii) the limited spatial scale
of the SB; (iii) the lack of convergence of most ideal MHD simulations; (iv)
side-effects of the SB symmetry and the non-trivial nature of the linear MRI;
(v) physical artifacts arising on the too small box scale due to periodic
boundary conditions. The computational and theoretical challenge posed by the
MHD turbulence problem in accretion disks cannot be met by the SB
approximation, as it has been used to date. A new strategy to confront this
challenge is proposed, based on techniques widely used in numerical studies of
turbulent flows - developing (e.g., with the help of local numerical studies) a
sub-grid turbulence model and implementing it in global calculations.


title:
Finite-Dimensional Representations of Hyper Loop Algebras Over
  Non-Algebraically Closed Fields

abstract:
  We study finite-dimensional representations of hyper loop algebras over
non-algebraically closed fields. The main results concern the classification of
the irreducible representations, the construction of the Weyl modules, base
change, tensor products of irreducible and Weyl modules, and the block
decomposition of the underlying abelian category. Several results are
interestingly related to the study of irreducible representations of polynomial
algebras and Galois theory.


title: Modeling the variability of shapes of a human placenta

abstract:
  While it is well-understood what a normal human placenta should look like, a
deviation from the norm can take many possible shapes. In this paper we propose
a mechanism for this variability based on the change in the structure of the
vascular tree.


title: Thermodynamics in variable speed of light theories

abstract:
  The perfect fluid in the context of a covariant variable speed of light
theory proposed by J. Magueijo is studied. On the one hand the modified first
law of thermodynamics together with a recipe to obtain equations of state are
obtained. On the other hand the Newtonian limit is performed to obtain the
nonrelativistic hydrostatic equilibrium equation for the theory. The results
obtained are used to determine the time variation of the radius of Mercury
induced by the variability of the speed of light ($c$), and the scalar
contribution to the luminosity of white dwarfs. Using a bound for the change of
that radius and combining it with an upper limit for the variation of the fine
structure constant, a bound on the time variation of $c$ is set. An independent
bound is obtained from luminosity estimates for Stein 2015B.


title: Vortex Condensation in the Dual Chern-Simons Higgs Model

abstract:
  The contribution of nontrivial vacuum (topological) excitations, more
specifically vortex configurations of the self-dual Chern-Simons-Higgs model,
to the functional partition function is considered. By using a duality
transformation, we arrive at a representation of the partition function in
terms of which explicit vortex degrees of freedom are coupled to a dual gauge
field. By matching the obtained action to a field theory for the vortices, the
physical properties of the model in the presence of vortex excitations are then
studied. In terms of this field theory for vortices in the self-dual
Chern-Simons Higgs model, we determine the location of the critical value for
the Chern-Simons parameter below which vortex condensation can happen in the
system. The effects of self-energy quantum corrections to the vortex field are
also considered.


title: Temporal Variations in the Sun's Rotational Kinetic Energy

abstract:
  AIM: To study the variation of the angular momentum and the rotational
kinetic energy of the Sun, and associated variations in the gravitational
multipole moments, on a timescale of the solar cycle. METHOD: Inverting
helioseismic rotational splitting data obtained by the Global Oscillation
Network Group and by the Michelson Doppler Imager on the Solar and Heliospheric
Observatory. RESULTS: The temporal variation in angular momentum and kinetic
energy at high latitudes (>\pi/4) through the convection zone is positively
correlated with solar activity, whereas at low latitudes it is anticorrelated,
except for the top 10% by radius where both are correlated positively.
CONCLUSION: The helioseismic data imply significant temporal variation in the
angular momentum and the rotational kinetic energy, and in the gravitational
multipole moments. The properties of that variation will help constrain
dynamical theories of the solar cycle.


title:
Signature of superconducting states in cubic crystal without inversion
  symmetry

abstract:
  The effects of absence of inversion symmetry on superconducting states are
investigated theoretically. In particular we focus on the noncentrosymmetric
compounds which have the cubic symmetry $O$ like Li$_2$Pt$_3$B. An appropriate
and isotropic spin-orbital interaction is added in the Hamiltonian and it acts
like a magnetic monopole in the momentum space. The consequent pairing
wavefunction has an additional triplet component in the pseudospin space, and a
Zeeman magnetic field $\bf{B}$ can induce a collinear supercurrent $\bf{J}$
with a coefficient $\kappa(T)$. The effects of anisotropy embedded in the cubic
symmetry and the nodal superconducting gap function on $\kappa(T)$ are also
considered. From the macroscopic perspectives, the pair of mutually induced
$\bf{J}$ and magnetization ${\bf{M}}$ can affect the distribution of magnetic
field in such noncentrosymmetric superconductors, which is studied through
solving the Maxwell equation in the Meissner geometry as well as the case of a
single vortex line. In both cases, magnetic fields perpendicular to the
external ones emerge as a signature of the broken symmetry.


title: Atmospheric Parameters of Field L and T Dwarfs

abstract:
  We present an analysis of the 0.95-14.5 micron spectral energy distributions
of nine field ultracool dwarfs with spectral types ranging from L1 to T4.5.
Effective temperatures, gravities, and condensate cloud sedimentation
efficiencies are derived by comparing the data to synthetic spectra computed
from atmospheric models that self-consistently include the formation of
condensate clouds. Derived effective temperatures decrease steadily through the
L1 to T4.5 spectral types and we confirm that the effective temperatures of
ultracool dwarfs at the L/T transition are nearly constant, decreasing by only
~200 K from spectral types L7.5 to T4.5. The two objects in our sample with
very red J-Ks colors are best fitted with synthetic spectra that have thick
clouds which hints at a possible correlation between the near-infrared colors
of L dwarfs and the condensate cloud properties. The fits to the two T dwarfs
in our sample (T2 and T4.5) also suggest that the clouds become thinner in this
spectral class, in agreement with previous studies. Restricting the fits to
narrower wavelength ranges (i.e., individual photometric bands) almost always
yields excellent agreement between the data and models. Limitations in our
knowledge of the opacities of key absorbers such as FeH, VO, and CH4 at certain
wavelengths remain obvious, however. The effective temperatures obtained by
fitting the narrower wavelength ranges can show a large scatter compared to the
values derived by fitting the full spectral energy distributions; deviations
are typically ~200 K and in the worst cases, up to 700 K.


title: Flattening Functions on Flowers

abstract:
  Let $T$ be an orientation-preserving Lipschitz expanding map of the circle
$\T$. A pre-image selector is a map $\tau:\T\to\T$ with finitely many
discontinuities, each of which is a jump discontinuity, and such that
$\tau(x)\in T^{-1}(x)$ for all $x\in\T$. The closure of the image of a
pre-image selector is called a flower, and a flower with $p$ connected
components is called a $p$-flower. We say that a real-valued Lipschitz function
can be Lipschitz flattened on a flower whenever it is Lipschitz cohomologous to
a constant on that flower.
  The space of Lipschitz functions which can be flattened on a given $p$-flower
is shown to be of codimension $p$ in the space of all Lipschitz functions, and
the linear constraints determining this subspace are derived explicitly. If a
Lipschitz function $f$ has a maximizing measure $S$ which is Sturmian (i.e. is
carried by a 1-flower), it is shown that $f$ can be Lipschitz flattened on some
1-flower carrying $S$.


title: Spin Dependence of Interfacial Reflection Phase Shift at Cu/Co Interface

abstract:
  The spin dependent reflection at the interface is the key element to
understand the spin transport. By completely solving the scattering problem
based on first principles method, we obtained the spin resolved reflectivity
spectra. The comparison of our theoretical results with experiment is good in a
large energy scale from Fermi level to energy above vacuum level. It is found
that interfacial distortion is crucial for understanding the spin dependence of
the phase gain at the Cu$|$Co interface. Near the Fermi level, image state
plays an important role to the phase accumulation in the copper film.


title:
Correction. Perfect simulation for a class of positive recurrent Markov
  chains

abstract:
  Correction to Annals of Applied Probability 17 (2007) 781--808
[doi:10.1214/105051607000000032].


title:
Fermion mass splitting, stability and naturalness problems in warped
  braneworld models

abstract:
  We generalize the Randall Sundrum warped braneworld model in six and higher
dimension and propose a resolution to the mass hierarchy among the standard
model fermions. The fine tuning problem in connection with the scalar mass
however is shown to reappear in a new guise in five dimensional warped model
when the two form antisymmetric tensor fields, a massless string mode,
propagates in the bulk. Finally the issue of modulus stabilization is
re-examined in presence of a bulk scalar by considering it's back-reaction on
the background geometry. The role of higher derivative term of the bulk scalar
is shown to be crucial to achieve modulus stabilization.


title: The differential rotation of epsilon Eri from MOST data

abstract:
  From high-precision MOST photometry spanning 35 days the existence of two
spots rotating with slightly differing periods is confirmed.
  From the marginal probability distribution of the derived differential
rotation parameter k its expectation value as well as confidence limits are
computed directly from the data. The result depends on the assumed range in
inclination i, not on the shape of the prior distributions. Two cases have been
considered: (a) The priors for angles, inclination i of the star and spot
latitudes beta_1,2, are assumed to be constant over i, beta_1, and beta_2. (b)
The priors are assumed to be constant over cosi, sin beta_1, and sin beta_2. In
both cases the full range of inclination is considered: 0^o< = i< = 90^o.
Scale-free parameters, i.e. periods and spot areas (in case of small spots) are
taken logarithmically. Irrespective of the shape of the prior, k is restricted
to 0.03 < = k < = 0.10 (one-sigma limits). The inclination i of the star is
photometrically ill-defined.


title: Functional approach for excess mass estimation in the density model

abstract:
  We consider a multivariate density model where we estimate the excess mass of
the unknown probability density $f$ at a given level $\nu>0$ from $n$ i.i.d.
observed random variables. This problem has several applications such as
multimodality testing, density contour clustering, anomaly detection,
classification and so on. For the first time in the literature we estimate the
excess mass as an integrated functional of the unknown density $f$. We suggest
an estimator and evaluate its rate of convergence, when $f$ belongs to general
Besov smoothness classes, for several risk measures. A particular care is
devoted to implementation and numerical study of the studied procedure. It
appears that our procedure improves the plug-in estimator of the excess mass.


title:
Supernovae in Low-Redshift Galaxy Clusters: Observations by the Wise
  Observatory Optical Transient Search (WOOTS)

abstract:
  We describe the Wise Observatory Optical Transient Search (WOOTS), a survey
for supernovae (SNe) and other variable and transient objects in the fields of
redshift 0.06-0.2 Abell galaxy clusters. We present the survey design and
data-analysis procedures, and our object detection and follow-up strategies. We
have obtained follow-up spectroscopy for all viable SN candidates, and present
the resulting SN sample here. Out of the 12 SNe we have discovered, seven are
associated with our target clusters while five are foreground or background
field events. All but one of the SNe (a foreground field event) are Type Ia
SNe. Our non-cluster SN sample is uniquely complete, since all SN candidates
have been either spectroscopically confirmed or ruled out. This allows us to
estimate that flux-limited surveys similar to WOOTS would be dominated (~80%)
by SNe Ia. Our spectroscopic follow-up observations also elucidate the
difficulty in distinguishing active galactic nuclei from SNe. In separate
papers we use the WOOTS sample to derive the SN rate in clusters for this
redshift range, and to measure the fraction of intergalactic cluster SNe. We
also briefly report here on some quasars and asteroids discovered by WOOTS.


title: On the ternary complex analysis and its applications

abstract:
  Previouly a possible extension of the complex number, together with its
connected trigonometry was introduced. In this paper we focuss on the simplest
case of ternary complex numbers. Then, some types of holomorphicity adapted to
the ternary complex numbers and the corresponding results upon integration of
differential forms are given. Several physical applications are given, and in
particuler one type of holomorphic function gives rise to a new form of
stationary magnetic field. The movement of a monopole type object in this field
is then studied and shown to be integrable. The monopole scattering in the
ternary field is finally studied.


title: Variant of the Clauser-Horne-Shimony-Holt inequality

abstract:
  We construct a Bell inequality from the Clauser-Horne-Shimony-Holt inequality
for two qubits that provides a stronger bound on the correlations of entangled
states than allowed by the CHSH inequality. The argument involved here can be
generalized to $n$ qubits. The inequalities obtained are violated by all the
generalized Greenberger-Horne-Zeilinger states of multiqubits.


title:
Combined Acoustic and Pronunciation Modelling for Non-Native Speech
  Recognition

abstract:
  In this paper, we present several adaptation methods for non-native speech
recognition. We have tested pronunciation modelling, MLLR and MAP non-native
pronunciation adaptation and HMM models retraining on the HIWIRE foreign
accented English speech database. The ``phonetic confusion'' scheme we have
developed consists in associating to each spoken phone several sequences of
confused phones. In our experiments, we have used different combinations of
acoustic models representing the canonical and the foreign pronunciations:
spoken and native models, models adapted to the non-native accent with MAP and
MLLR. The joint use of pronunciation modelling and acoustic adaptation led to
further improvements in recognition accuracy. The best combination of the above
mentioned techniques resulted in a relative word error reduction ranging from
46% to 71%.


title:
Charge Oscillations in Superconducting Nanodevices Coupled to External
  Environments

abstract:
  Charge oscillations in certain nanodevices, more specifically the so-called
Superconducting Cooper Pair Boxes (SCB), are usually interpreted as an effect
of macroscopic quantum coherence; an alternative explanation is however
possible in terms of the Gross-Pitaewski equation for the classical order
parameter. These two explanations are based on different quantum states
assigned to the SCB, occupation number states in the first case, coherent-like
states in the second one. We show that, when the SCB is weakly coupled to an
external source of noise and dissipation, occupation number states are much
more unstable than coherent ones.


title: Surface Effects on Oxide Heterostructures

abstract:
  We report on surface effects on the electronic properties of interfaces in
epitaxial LaAlO$_3$/SrTiO$_3$ heterostructures. Our results are based on
first-principles electronic structure calculations for well-relaxed multilayer
configurations, terminated by an ultrathin LaAlO$_3$ surface layer. On varying
the thickness of this layer, we find that the interface conduction states are
subject to almost rigid band shifts due to a modified Fermi energy. Confirming
experimental data, the electronic properties of heterointerfaces therefore can
be tuned systematically by alterating the surface-interface distance. We expect
that this mechanism is very general and applies to most oxide heterostructures.


title: Geometric Linearization of Ordinary Differential Equations

abstract:
  The linearizability of differential equations was first considered by Lie for
scalar second order semi-linear ordinary differential equations. Since then
there has been considerable work done on the algebraic classification of
linearizable equations and even on systems of equations. However, little has
been done in the way of providing explicit criteria to determine their
linearizability. Using the connection between isometries and symmetries of the
system of geodesic equations criteria were established for second order
quadratically and cubically semi-linear equations and for systems of equations.
The connection was proved for maximally symmetric spaces and a conjecture was
put forward for other cases. Here the criteria are briefly reviewed and the
conjecture is proved.


title: A local-global problem for linear differential equations

abstract:
  An inhomogeneous linear differential equation Ly=f over a global differential
field can have a formal solution for each place without having a global
solution. The vector space lgl(L) measures this phenomenon. This space is
interpreted in terms of cohomology of linear algebraic groups and is computed
for abelian differential equations and for regular singular equations. An
analogue of Artin reciprocity for abelian differential equations is given.
Malgrange's work on irregularity is reproved in terms of cohomology of linear
algebraic groups.


title: New Dirac quantum modes in moving frames of the de Sitter spacetime

abstract:
  Recently a new time-evolution picture of the Dirac quantum mechanics was
defined in charts with spatially flat Robertson-Walker metrics, under the name
of Schr\"{o}dinger picture [I. I. Cot\u{a}escu, arXiv:0708.0734] . In the
present paper new Dirac quantum modes are found in moving charts of the de
Sitter spacetime using the technical advantages offered by this picture. The
principal result is a new set of energy eigenspinors which behave as polarized
plane waves and form a complete system of orthonormalized solutions of the free
Dirac equation.


title: Transversity from two pion interference fragmentation

abstract:
  We present calculation on the azimuthal spin asymmetries for pion pair
production in semi-inclusive deep inelastic scattering (SIDIS) process at both
HERMES and COMPASS kinematics, with transversely polarized proton, deuteron and
neutron targets. We calculate the asymmetry by adopting a set of
parametrization of the interference fragmentation functions and two different
models for the transversity. We find that the result for the proton target is
insensitive to the approaches of the transversity but more helpful to
understand the interference fragmentation functions. However, for the neutron
target, which can be obtained through using deuteron and {$^3$He} targets, we
find different predictions for different approaches to the transversity. Thus
probing the two pion interference fragmentation from the neutron can provide us
more interesting information on the transversity.


title:
Four-dimensional CP$^1+$ U(1) lattice gauge theory for 3D
  antiferromagnets: Phase structure, gauge bosons and spin liquid

abstract:
  In this paper we study the lattice CP$^1$ model in (3+1) dimensions coupled
with a dynamical compact U(1) gauge field. This model is an effective field
theory of the $s={1 \over 2}$ antiferromagnetic Heisenberg spin model in three
spatial dimensions. By means of Monte Carlo simulations, we investigate its
phase structure. There exist the Higgs, Coulomb and confinement phases, and the
parameter regions of these phases are clarified. We also measure magnetization
of O(3) spins, energy gap of spin excitations, and mass of gauge boson. Then we
discuss the relationship between these three phases and magnetic properties of
the high-$T_{\rm c}$ cuprates, in particular the possibility of
deconfined-spinon phase. Effect of dimer-like spin exchange coupling and
ring-exchange coupling is also studied.


title: Progress in hadron structure physics on the lattice

abstract:
  This is a review of progress in hadron structure physics from lattice QCD.
Recent results on the structure of the nucleon and the pion in terms of
(transition) form factors, moments of distribution amplitudes and (generalized)
parton distribution functions are presented. These observables allow us to
investigate a number of fundamental physics questions related to e.g. the
distribution of charge and momentum in hadrons, the spin structure of the
nucleon and the pion, and correlations between spin, orbital angular momentum
and coordinate degrees of freedom. Chiral extrapolations of selected lattice
results are presented and compared to results from experiment and
phenomenology. We conclude that lattice simulations already today strongly
contribute to our understanding of the structure of hadrons.


title: Anyonic statistics with continuous variables

abstract:
  We describe a continuous-variable scheme for simulating the Kitaev lattice
model and for detecting statistics of abelian anyons. The corresponding quantum
optical implementation is solely based upon Gaussian resource states and
Gaussian operations, hence allowing for a highly efficient creation,
manipulation, and detection of anyons. This approach extends our understanding
of the control and application of anyons and it leads to the possibility for
experimental proof-of-principle demonstrations of anyonic statistics using
continuous-variable systems.


title: Nucleon electroweak form factors in a meson-cloud model

abstract:
  The meson-cloud model of the nucleon consisting of a system of three valence
quarks surrounded by a meson cloud is applied to study the electroweak
structure of the proton and neutron. The electroweak nucleon form factors are
calculated within a light-front approach, by obtaining an overall good
description of the experimental data. Charge densities as a function of the
transverse distance with respect to the direction of the three-momentum
transfer are also discussed.


title:
Self-organization in Trees and Motifs of Two-Dimensional Chaotic Maps
  with Time Delay

abstract:
  We study two-dimensional chaotic standard maps coupled along the edges of
scale-free trees and tree-like subgraph (4-star) with a non-symplectic coupling
and time delay between the nodes. Apart from the chaotic and regular 2-periodic
motion, the coupled map system exhibits variety of dynamical effects in a wide
range of coupling strengths. This includes dynamical localization, emergent
periodicity, and appearance of strange non-chaotic attractors. Near the strange
attractors we find long-range correlations in the intervals of return-times to
specified parts of the phase space. We substantiate the analysis with the
finite-time Lyapunov stability. We also give some quantitative evidence of how
the small-scale dynamics at 4-star motifs participates in the genesis of the
collective behavior at the whole network.


title:
Density correlations in ultracold Fermi systems within the exact
  Richardson solution

abstract:
  We discuss the occupation number correlations in an ultracold system of
interacting fermionic atoms. For a system with a special energy-level
distribution, viz. two multiply-degenerate levels, explicit expressions for the
correlation functions are derived in a canonical approach using the exact
ground state wavefunction of the reduced BCS Hamiltonian. We evaluate the
correlators numerically for different interaction strength and find analytical
expressions in some limiting cases. Due to the underlying fermionic nature of
the pairs the occupations are predominantly anti-correlated and their
statistics is a multinomial distribution.


title: Modified Dispersion Relations and trans-Planckian Physics

abstract:
  We consider modified dispersion relations in quantum field theory on curved
space-time. Such relations, despite breaking the local Lorentz invariance at
high energy, are considered in several phenomenological approaches to quantum
gravity. Their existence involves a modification of the formalism of quantum
field theory, starting from the problem of finding the scalar Green's functions
up to the renormalization of various quantum expectation values. In this work
we consider a simple example of such modifications, in the case of ultra-static
metric. We show how to overcome the lack of Lorentz invariance by introducing a
preferred frame, with respect to which we can express the Green's functions as
an integral over all frequencies of a space-dependent function. The latter can
be expanded in momentum space, and by integrating over all frequencies, we
finally find the expansion of the Green's function up to four derivatives of
the metric tensor. The relation with the proper-time formalism is also
discussed.


title: Gauge symmetry and Slavnov-Taylor identities for randomly stirred fluids

abstract:
  The path integral for randomly forced incompressible fluids is shown to have
an underlying Becchi-Rouet-Stora (BRS) symmetry as a consequence of Galilean
invariance. This symmetry must be respected to have a consistent generating
functional, free from both an overall infinite factor and spurious relations
amongst correlation functions. We present a procedure for respecting this BRS
symmetry, akin to gauge fixing in quantum field theory. Relations are derived
between correlation functions of this gauge fixed, BRS symmetric theory,
analogous to the Slavnov-Taylor identities of quantum field theory.

categories: hep-th cond-mat.stat-mech hep-lat hep-ph physics.flu-dyn


title: Continuous Limit of Discrete Systems with Long-Range Interaction

abstract:
  Discrete systems with long-range interactions are considered. Continuous
medium models as continuous limit of discrete chain system are defined.
Long-range interactions of chain elements that give the fractional equations
for the medium model are discussed. The chain equations of motion with
long-range interaction are mapped into the continuum equation with the Riesz
fractional derivative. We formulate the consistent definition of continuous
limit for the systems with long-range interactions. In this paper, we consider
a wide class of long-range interactions that give fractional medium equations
in the continuous limit. The power-law interaction is a special case of this
class.


title: Unveiling the nature of RX J0002+6246 with XMM-Newton

abstract:
  The X-ray source RX J0002+6246 was discovered close to the supernova remnant
CTB1 in a ROSAT observation performed in 1992. The source phenomenology (soft
spectrum, apparent lack of counterparts, possible pulsations at 242 ms, hints
for surrounding diffuse emission) led to interpret it as an isolated neutron
star in a new supernova remnant. We have analysed an archival XMM-Newton
observation performed in 2001. The source coordinates, as computed on the
XMM-Newton images, coincide with those of a bright source listed in optical and
infrared catalogues. The X-ray spectrum is well described by an optically thin
plasma model. No fast pulsations are seen, nor clear evidence of a supernova
remnant associated to the source. Thus, we conclude that RX J0002+6246 is not
an isolated neutron star, but the X-ray counterpart of the bright
optical/infrared source, most likely a F7 spectral class star located at about
0.2 kpc.


title: Pseudo-Goldstone Higgs Production via Gluon Fusion

abstract:
  The gluon-gluon-higgs amplitude is investigated in the context of 5D models
of gauge-higgs unification. A simple algorithm allows to include, in a fully
analytical way, the contribution of the whole Kaluza-Klein tower of a 5D quark
to the amplitude. This algorithm is applied to realistic models based on SO(5)
symmetry. Within the studied classes of models, the higgs production cross
section is always suppressed.


title: Instruction sequences with indirect jumps

abstract:
  We study sequential programs that are instruction sequences with direct and
indirect jump instructions. The intuition is that indirect jump instructions
are jump instructions where the position of the instruction to jump to is the
content of some memory cell. We consider several kinds of indirect jump
instructions. For each kind, we define the meaning of programs with indirect
jump instructions of that kind by means of a translation into programs without
indirect jump instructions. For each kind, the intended behaviour of a program
with indirect jump instructions of that kind under execution is the behaviour
of the translated program under execution on interaction with some memory
device.


title: Multidimensional Gauss Reduction Theory for conjugacy classes of SL(n,Z)

abstract:
  In this paper we describe the set of conjugacy classes in the group SL(n,Z).
We expand geometric Gauss Reduction Theory that solves the problem for SL(2,Z)
to the multidimensional case. Further we find complete invariant of classes in
terms of multidimensional Klein-Voronoi continued fractions, where
$\varsigma$-reduce Hessenberg matrices play the role of reduced matrices.


title: Dynamical Transitions of a Driven Ising Interface

abstract:
  We study the structure of an interface in a three dimensional Ising system
created by an external non-uniform field $H({\bf r},t)$. $H$ changes sign over
a two dimensional plane of arbitrary orientation. When the field is pulled with
velocity ${\bf v}_e$, (i.e. $H({\bf r},t) = H({\bf r - v_e}t)$), the interface
undergoes a several dynamical transitions. For low velocities it is pinned by
the field profile and moves along with it, the distribution of local slopes
undergoing a series of commensurate-incommensurate transitions. For large ${\bf
v}_e$ the interface de-pinns and grows with KPZ exponents.


title:
Covariant formulation of Noether's Theorem for translations on
  kappa-Minkowski spacetime

abstract:
  The problem of finding a formulation of Noether's theorem in noncommutative
geometry is very important in order to obtain conserved currents and charges
for particles in noncommutative spacetimes. In this paper, we formulate
Noether's theorem for translations of kappa-Minkowski noncommutative spacetime
on the basis of the 5-dimensional kappa-Poincare' covariant differential
calculus. We focus our analysis on the simple case of free scalar theory. We
obtain five conserved Noether currents, which give rise to five energy-momentum
charges. By applying our result to plane waves it follows that the
energy-momentum charges satisfy a special-relativity dispersion relation with a
generalized mass given by the fifth charge. In this paper we provide also a
rigorous derivation of the equation of motion from Hamilton's principle in
noncommutative spacetime, which is necessary for the Noether analysis.


title:
On extracting information about hadron-nuclear interaction from hadronic
  atom level shifts

abstract:
  It is argued, that adjusting strong potentials directly to observed hadronic
atom level shifts may lead to significantly different scattering lengths, than
those, predicted by the Deser formula. On the example of the 1s level shift of
kaonic hydrogen it is demonstrated, that the usually adopted Deser values
deduced from the two recent measurements in KEK and by the DEAR Collaboration
$a_D({\rm KEK}) = 0.78 - 0.49i$ fm and $a_D({\rm DEAR}) = 0.47 - 0.3i$ fm
should be replaced by $a_s({\rm KEK})\simeq 0.85 - 0.62i$ fm and $a_s({\rm
DEAR})\simeq 0.49 - 0.35i$ fm, correspondingly.


title: An interface group for process components

abstract:
  We take a process component as a pair of an interface and a behaviour. We
study the composition of interacting process components in the setting of
process algebra. We formalize the interfaces of interacting process components
by means of an interface group. An interesting feature of the interface group
is that it allows for distinguishing between expectations and promises in
interfaces of process components. This distinction comes into play in case
components with both client and server behaviour are involved.


title: Fast hadron freeze-out generator, part II: noncentral collisions

abstract:
  The fast Monte Carlo procedure of hadron generation developed in our previous
work is extended to describe noncentral collisions of nuclei. We consider
different possibilities to introduce appropriate asymmetry of the freeze-out
hyper-surface and flow velocity profile. For comparison with other models and
experimental data we demonstrate the results based on the standard
parametrizations of the hadron freeze-out hyper-surface and flow velocity
profile assuming either a common chemical and thermal freeze-out or the
chemically frozen evolution from chemical to thermal freeze-out. The C++
generator code is written under the ROOT framework and is available for public
use at http://uhkm.jinr.ru/


title: Machine structure oriented control code logic

abstract:
  Control code is a concept that is closely related to a frequently occurring
practitioner's view on what is a program: code that is capable of controlling
the behaviour of some machine. We present a logical approach to explain issues
concerning control codes that are independent of the details of the behaviours
that are controlled. Using this approach, such issues can be explained at a
very abstract level. We illustrate this among other things by means of an
example about the production of a new compiler from an existing one. The
approach is based on abstract machine models, called machine structures. We
introduce a model of systems that provide execution environments for the
executable codes of machine structures and use it to go into portability of
control codes.


title:
Nonradial p-modes in the G9.5 giant epsilon Oph? Pulsation model fits to
  MOST photometry

abstract:
  The G9.5 giant eps Oph shows evidence of radial p-mode pulsations in both
radial velocity and luminosity. We re-examine the observed frequencies in the
photometry and radial velocities and find a best model fit to 18 of the 21 most
significant photometric frequencies. The observed frequencies are matched to
both radial and nonradial modes in the best model fit. The small scatter of the
frequencies about the model predicted frequencies indicate that the average
lifetimes of the modes could be as long as 10-20d. The best fit model itself,
constrained only by the observed frequencies, lies within 1 sigma of eps Oph's
position in the HR-diagram and the interferometrically determined radius.


title: On the operating unit size of load/store architectures

abstract:
  We introduce a strict version of the concept of a load/store instruction set
architecture in the setting of Maurer machines. We take the view that
transformations on the states of a Maurer machine are achieved by applying
threads as considered in thread algebra to the Maurer machine. We study how the
transformations on the states of the main memory of a strict load/store
instruction set architecture that can be achieved by applying threads depend on
the operating unit size, the cardinality of the instruction set, and the
maximal number of states of the threads.


title:
Conduction Effect of Thermal Radiation in a Metal Shield Pipe in a
  Cryostat for a Cryogenic Interferometric Gravitational Wave Detector

abstract:
  A large heat load caused by thermal radiation through a metal shield pipe was
observed in a cooling test of a cryostat for a prototype of a cryogenic
interferometric gravitational wave detector. The heat load was approximately
1000 times larger than the value calculated by the Stefan-Boltzmann law. We
studied this phenomenon by simulation and experiment and found that it was
caused by the conduction of thermal radiation in a metal shield pipe.


title: A thread calculus with molecular dynamics

abstract:
  We present a theory of threads, interleaving of threads, and interaction
between threads and services with features of molecular dynamics, a model of
computation that bears on computations in which dynamic data structures are
involved. Threads can interact with services of which the states consist of
structured data objects and computations take place by means of actions which
may change the structure of the data objects. The features introduced include
restriction of the scope of names used in threads to refer to data objects.
Because that feature makes it troublesome to provide a model based on
structural operational semantics and bisimulation, we construct a projective
limit model for the theory.


title: Evanescent character of the repulsive thermal Casimir force

abstract:
  The physical origin of the negative thermal correction to the Casimir force
between metals is clarified. For this purpose the asymptotic behavior of the
thermal Casimir force is analyzed at large and small distances in the real
frequency representation. Contributions from propagating and evanescent waves
are considered separately. At large distances they cancel each other in
substantial degree so that only the attractive Lifshitz limit survives. At
smaller separations the repulsive evanescent contribution of s-polarization
dominates in the case of two metals or a metal and a high-permittivity
dielectric. Common origin and order of magnitude of the repulsion in these two
cases demonstrate naturalness of the controversial large thermal correction
between metals.


title: An accurate distance to 2M1207Ab

abstract:
  In April 2004 the first image was obtained of a planetary mass companion (now
known as 2M1207 b) in orbit around a self-luminous object different from our
own Sun (the young brown dwarf 2MASSW J1207334-393254, hereafter 2M1207 A).
2M1207 b probably formed via fragmentation and gravitational collapse, offering
proof that such a mechanism can form bodies in the planetary mass regime.
However, the predicted mass, luminosity, and radius of 2M1207 b depend on its
age, distance, and other observables such as effective temperature. To refine
our knowledge of the physical properties of 2M1207 b and its nature, we
obtained an accurate determination of the distance to the 2M1207 A and b system
by measurements of its trigonometric parallax at the milliarcsec level. With
the ESO NTT/SUSI2 telescope, in 2006 we began a campaign of photometric and
astrometric observations to measure the trigonometric parallax of 2M1207 A. An
accurate distance ($52.4\pm 1.1$ pc) to 2M1207A was measured. From distance and
proper motions we derived spatial velocities fully compatible with TWA
membership. With this new distance estimate, we discuss three scenarios
regarding the nature of 2M1207 b: (1) a cool ($1150\pm150$ K) companion of mass
$4\pm1$ M$_{\rm{Jup}}$, (2) a warmer ($1600\pm100$ K) and heavier ($8\pm2$
M$_{\rm{Jup}}$) companion occulted by an edge-on circum-secondary disk or (3) a
hot protoplanet collision afterglow.


title:
Clustering of galaxies at 3.6 microns in the Spitzer Wide-area Infrared
  Extragalactic legacy survey

abstract:
  We investigate the clustering of galaxies selected in the 3.6 micron band of
the Spitzer Wide-area Infrared Extragalactic (SWIRE) legacy survey. The angular
two-point correlation function is calculated for eleven samples with flux
limits of S_3.6 > 4-400 mujy, over an 8 square degree field. The angular
clustering strength is measured at >5-sigma significance at all flux limits,
with amplitudes of A=(0.49-29)\times10^{-3} at one degree, for a power-law
model, A\theta^{-0.8}. We estimate the redshift distributions of the samples
using phenomological models, simulations and photometric redshifts, and so
derive the spatial correlation lengths. We compare our results with the GalICS
(Galaxies In Cosmological Simulations) models of galaxy evolution and with
parameterized models of clustering evolution. The GalICS simulations are
consistent with our angular correlation functions, but fail to match the
spatial clustering inferred from the phenomological models or the photometric
redshifts. We find that the uncertainties in the redshift distributions of our
samples dominate the statistical errors in our estimates of the spatial
clustering. At low redshifts (median z<0.5) the comoving correlation length is
approximately constant, r_0=6.1\pm0.5h^{-1} Mpc, and then decreases with
increasing redshift to a value of 2.9\pm0.3h^{-1} Mpc for the faintest sample,
for which the median redshift is z=1. We suggest that this trend can be
attributed to a decrease in the average galaxy and halo mass in the fainter
flux-limited samples, corresponding to changes in the relative numbers of
early- and late-type galaxies. However, we cannot rule out strong evolution of
the correlation length over 0.5<z<1.


title: The high energy emission from black holes

abstract:
  The origin of the high energy emission (X-rays and gamma-rays) from black
holes is still a matter of debate. We present new evidence that hard X-ray
emission in the low/hard state may not be dominated by thermal Comptonization.
We present an alternative scenario for the origin of the high energy emission
that is well suited to explain the high energy emission from GRO J1655-40.


title:
Proceedings of the first Congress on North-South collaboration in
  Physics research

abstract:
  The first Congress on North-South collaboration in Physics research was held
in Oujda Morocco, between April 9th and 13th, 2007. The congress was based on
talks giving an overview of relevant subjects both from experiments and theory
in all fields of physics. They focused on projects which could bring fruitful
collaborations between Europe and under developed countries. The congress was
meant to bring experience and skills to these countries in research and
teaching at the doctoral level.


title:
A Unified Model of $\alpha$-Helix/$\beta$-Sheet/Random-Coil Transition
  in Proteins

abstract:
  The theory of transition between $\alpha$-helix, $\beta$-sheet and random
coil conformation of a protein is discussed through a simple model, that
includes both short and long-range interactions. Besides the bonding parameter
and helical initiation factor in Zimm-Bragg model, three new parameters are
introduced to describe beta structure: the local constraint factor for a single
residue to be contained in a $\beta$-strand, the long-range bonding parameter
that accounts for the interaction between a pair of bonded $\beta$-strands, and
a correction factor for the initiation of a $\beta$-sheet. Either increasing
local constraint factor or long-range bonding parameter can cause a transition
from $\alpha$-helix or random coil conformation to $\beta$-sheet conformation.
The sharpness of transition depends on the competition between short and
long-range interactions. Other effective factors, such as the chain length and
temperature, are also discussed. In this model, the entropy due to different
ways to group $\beta$-strands into different $\beta$-sheets gives rise to
significant contribution to partition function, and makes major differences
between beta structure and helical structure.


title: Fick's law and Fokker-Planck Equation in inhomogeneous environments

abstract:
  In inhomogeneous environments, the correct expression of the diffusive flux
is often not given by the Fick's law $\Gamma = - D \nabla n $. The most general
hydrodynamic equation modelling diffusion is indeed the Fokker-Planck Equation
(FPE). The microscopic dynamics of each specific system may affect the form of
the FPE, either establishing connections between the diffusion and the
convection term, as well as providing supplementary terms. In particular, the
Fick's form for the Diffusion Equation may arise only in consequence of a
specific kind of microscopic dynamics. It is also shown how, in the presence of
sharp inhomogeneities, even the hydrodynamic FPE limit may becomes inaccurate
and mask some features of the true solution, as computed from the Master
Equation.


title: Bose-Einstein condensation and gauge symmetry breaking

abstract:
  The fundamental problem is analized, the relation between Bose-Einstein
condensation and spontaneous gauge symmetry breaking. This relation is largerly
misunderstood in physics community. Numerous articles and books contain the
statement that, though gauge symmetry breaking helps for describing
Bose-Einstein condensation, but the latter, in principle, does not require any
symmetry breaking. This, however, is not correct. The analysis is based on the
known mathematical theorems. But in order not to overcomplicate the
presentation and to make it accessible to all readers, technical details are
often omitted here. The emphasis is made on the following basic general facts:
Spontaneous breaking of gauge symmetry is the necessary and sufficient
condition for Bose-Einstein condensation. Condensate fluctuations, in
thermodynamic limit, are negligible. Their catastrophic behavior can arise only
as a result of incorrect calculations, when a Bose-condensed system is
described without gauge symmetry breaking. It is crucially important to employ
the representative statistical ensembles equipped with all conditions that are
necessary for a unique and mathematically correct description of the given
statistical system. Only then one is able to develop a self-consistent theory,
free of paradoxes.


title: Duality for partial group actions

abstract:
  Given a finite group G acting as automorphisms on a ring A, the skew group
ring A*G is an important tool for studying the structure of G-stable ideals of
A. The ring A*G is G-graded, i.e.G coacts on A*G. The Cohen-Montgomery duality
says that the smash product A*G#k[G]^* of A*G with the dual group ring k[G]^*
is isomorphic to the full matrix ring M_n(A) over A, where n is the order of G.
In this note we show how much of the Cohen-Montgomery duality carries over to
partial group actions in the sense of R.Exel. In particular we show that the
smash product (A*_\alpha G)#k[G]^* of the partial skew group ring A*_\alpha G
and k[G]^* is isomorphic to a direct product of the form K x eM_n(A)e where e
is a certain idempotent of M_n(A) and K is a subalgebra of (A *_\alpha
G)#k[G]^*. Moreover A*_\alpha G is shown to be isomorphic to a separable
subalgebra of eM_n(A)e. We also look at duality for infinite partial group
actions and for partial Hopf actions.


title:
The Great Observatories Origins Deep Survey. VLT/FORS2 Spectroscopy in
  the GOODS-South Field: Part III

abstract:
  Aims. We present the full data set of the spectroscopic campaign of the
  ESO/GOODS program in the GOODS-South field, obtained with the
  FORS2 spectrograph at the ESO/VLT. Method. Objects were selected as
candidates for VLT/FORS2 observations primarily based on the expectation that
the detection and measurement of their spectral features would benefit from the
high throughput and spectral resolution of FORS2. The reliability of the
redshift estimates is assessed using the redshift-magnitude and color-redshift
diagrams, and comparing the results with public data. Results. Including the
third part of the spectroscopic campaign (12 masks) to the previous work (26
masks, Vanzella et al. 2005, 2006), 1715 spectra of 1225 individual targets
have been analyzed. The actual spectroscopic catalog provides 887 redshift
determinations. The typical redshift uncertainty is estimated to be sigma(z) ~
0.001. Galaxies have been selected adopting different color criteria and using
photometric redshifts. The resulting redshift distribution typically spans two
domains: from z=0.5 to 2 and z=3.5 to 6.3. The reduced spectra and the derived
redshifts are released to the community through the ESO web page
http://www.eso.org/science/goods/


title: Quantum Weibel Instability

abstract:
  The Weibel instability is analyzed for quantum plasmas described by the
Wigner-Maxwell model. For a suitable class of electromagnetic potentials, the
Wigner-Maxwell system is linearized yielding a general dispersion relation for
transverse electromagnetic waves. For a double Gaussian equilibrium with
temperature anisotropy, the derived dispersion relation generalizes the
classical Weibel instability equation. More detailed analytical results are
obtained for the cases of extreme temperature anisotropy and for a
three-dimensional water bag distribution. In all cases, quantum effects tends
to weaken or suppress the instability. Applications are discussed for dense
astrophysical objects like white dwarfs and neutron stars as well as for
tunnel-ionized plasmas with controllable perpendicular plasma temperature.


title: Phase transitions induced by saddle points of vanishing curvature

abstract:
  Based on the study of saddle points of the potential energy landscapes of
generic classical many-particle systems, we present a necessary criterion for
the occurrence of a thermodynamic phase transition. Remarkably, this criterion
imposes conditions on microscopic properties, namely curvatures at the saddle
points of the potential, and links them to the macroscopic phenomenon of a
phase transition. We apply our result to two exactly solvable models,
corroborating that the criterion derived is not only valid, but also sharp and
useful: For both models studied, the criterion excludes the occurrence of a
phase transition for all values of the potential energy but the transition
energy. This result adds a geometrical ingredient to an established topological
condition for the occurrence of a phase transition, thereby providing an answer
to the long standing question of which topology changes in configuration space
can induce a phase transition.


title: Anisotropic solitons in dipolar Bose-Einstein Condensates

abstract:
  Starting with a Gaussian variational ansatz, we predict anisotropic bright
solitons in quasi-2D Bose-Einstein condensates consisting of atoms with dipole
moments polarized \emph{perpendicular} to the confinement direction. Unlike
isotropic solitons predicted for the moments aligned with the confinement axis
[Phys. Rev. Lett. \textbf{95}, 200404 (2005)], no sign reversal of the
dipole-dipole interaction is necessary to support the solitons. Direct 3D
simulations confirm their stability.


title:
Matter-wave squeezing and the generation of SU(1,1) and SU(2)
  coherent-states via Feshbach resonances

abstract:
  Pair operators for boson and fermion atoms generate SU(1,1) and SU(2) Lie
algebras, respectively. Consequently, the pairing of boson and fermion atoms
into diatomic molecules via Feshbach resonances, produces SU(1,1) and SU(2)
coherent states, making bosonic pairing the matter-wave equivalent of
parametric coupling and fermion pairing equivalent to the Dicke model of
quantum optics. We discuss the properties of atomic states generated in the
dissociation of molecular Bose-Einstein condensates into boson or fermion
constituent atoms. The SU(2) coherent states produced in dissociation into
fermions give Poissonian atom-number distributions, whereas the SU(1,1) states
generated in dissociation into bosons result in super-poissonian distributions,
in analogy to two-photon squeezed states. In contrast, starting from an atomic
gas produces coherent number distributions for bosons and super-poissonian
distributions for fermions.


title:
The Aharonov-Bohm-Effect, Non-commutative Geometry, Dislocation Theory,
  and Magnetism

abstract:
  The four items mentioned in the title are put into context in an informal
way.


title: First order transition in a three dimensional disordered system

abstract:
  We present the first detailed numerical study in three dimensions of a
first-order phase transition that remains first-order in the presence of
quenched disorder (specifically, the ferromagnetic/paramagnetic transition of
the site-diluted four states Potts model). A tricritical point, which lies
surprisingly near to the pure-system limit and is studied by means of
Finite-Size Scaling, separates the first-order and second-order parts of the
critical line. This investigation has been made possible by a new definition of
the disorder average that avoids the diverging-variance probability
distributions that plague the standard approach. Entropy, rather than free
energy, is the basic object in this approach that exploits a recently
introduced microcanonical Monte Carlo method.


title: Stringy cosmic strings in matter coupled N=2, d=4 supergravity

abstract:
  We extend the system of ungauged N=2, d=4 supergravity coupled to vector
multiplets and hypermultiplets with 2-form potentials. The maximal number of
2-form potentials that one may introduce is equal to the number of isometries
of either the special Kaehler or quaternionic Kaehler sigma model. We show that
the local supersymmetry algebra can be realized on the 2-form potentials. These
2-forms couple electrically to strings which we refer to as stringy cosmic
strings. The 1/2 BPS bosonic world-sheet actions for these strings are
constructed and we discuss the properties of the 1/2 BPS stringy cosmic string
solutions.


title: Weighted power variations of iterated Brownian motion

abstract:
  We characterize the asymptotic behaviour of the weighted power variation
processes associated with iterated Brownian motion. We prove weak convergence
results in the sense of finite dimensional distributions, and show that the
laws of the limiting objects can always be expressed in terms of three
independent Brownian motions X, Y and B, as well as of the local times of Y. In
particular, our results involve ``weighted'' versions of Kesten and Spitzer's
Brownian motion in random scenery. Our findings extend the theory initiated by
Khoshnevisan and Lewis (1999), and should be compared with the recent result by
Nourdin and R\'eveillac (2008), concerning the weighted power variations of
fractional Brownian motion with Hurst index H=1/4.


title: Liouville and Bogoliubov Equations with Fractional Derivatives

abstract:
  The Liouville equation, first Bogoliubov hierarchy and Vlasov equations with
derivatives of non-integer order are derived. Liouville equation with
fractional derivatives is obtained from the conservation of probability in a
fractional volume element. This equation is used to obtain Bogoliubov hierarchy
and fractional kinetic equations with fractional derivatives. Statistical
mechanics of fractional generalization of the Hamiltonian systems is discussed.
Fractional kinetic equation for the system of charged particles are considered.


title: Inclusive Measure of |V_ub| with the Analytic Coupling Model

abstract:
  By analyzing B -> X_u l nu_l spectra with a model based on soft-gluon
resummation and an analytic time-like QCD coupling, we obtain |V_ub| = (3.76
+-0.13 +- 0.22)*10^(-3), where the first and the second error refers to
experimental and theoretical errors, respectively. The V_ub value is obtained
from the available measured semileptonic branching fractions in limited regions
of the phase-space. The distributions in the lepton energy E_l, the hadron
invariant mass m_X, the light-cone momentum P_+ = E_X - p_X, together with the
double distributions in (m_X,q^2) and (E_l,s_h^max), are used to select the
phase-space regions. The q^2 is the dilepton squared momentum and s_h^max is
the maximal m_X^2 at fixed q^2 and E_l. The V_ub value obtained is in complete
agreement with the value coming from exclusive B decays and from an over-all
fit to the Standard Model parameters. We show that the slight disagreement (up
to +2 sigma) with respect to previous inclusive measurements is not related to
different choices for the b (and c) masses but to a different modelling of the
threshold (Sudakov) region.


title:
Confinement controlled dissociation of a molecular Bose-Einstein
  condensate

abstract:
  We study the collective two-channel dissociation dynamics of a molecular
Bose-Einstein condensate into bosonic fragments under tight harmonic
confinement. Bose-stimulated dissociation in either channel can only take place
provided that the respective trap size $l_i$ for the fragments is large with
respect to the healing length $\zeta_i$ of the atom-molecule resonance. Thus,
even when both channels are equally coupled, differences in mass or in
dynamical polarizability enable the control of the reaction outcome by
variation of the trap frequency. In particular, if $l_1>\zeta_1$ and
$l_2<\zeta_2$, only the first channel will be amplified. This behavior
demonstrate a unique feature of 'superchemistry' wherein a chemical reaction
may be controlled by the manipulation of the reaction vessel.


title:
Deep Extragalactic VLBI-Optical Survey (DEVOS) II. Efficient VLBI
  detection of SDSS quasars

abstract:
  Context: The Deep Extragalactic VLBI-Optical Survey (DEVOS) aims at
constructing a large sample of compact radio sources up to two orders of
magnitude fainter than those studied in other Very Long Baseline Interferometry
(VLBI) surveys. Optical identification of the objects is ensured by selecting
them from the Sloan Digital Sky Survey (SDSS) list. Aims: While continuing to
build up the DEVOS data base, we investigated how the VLBI detection rate could
be enhanced by refining the initial selection criteria introduced in the first
paper of this series. Methods: We observed 26 sources in two adjacent, slightly
overlapping 2 deg radius fields with the European VLBI Network (EVN) at 5 GHz
frequency on 2 March 2007.The phase-reference calibrator quasars were
J1616+3621 and J1623+3909. The objects selected were unresolved both in the
Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey catalogue
and the SDSS Data Release 4. Results: We present images of milli-arcsecond
(mas) scale radio structures and accurate coordinates of 24 extragalactic
sources. Most of them have never been imaged with VLBI. Twenty-two compact
radio sources (85% of our initial sample) are considered as VLBI detections of
the corresponding optical quasars in SDSS. We found an efficient way to
identify quasars as potential VLBI targets with mas-scale compact radio
stucture at >1 mJy level, based only on the FIRST and SDSS catalogue data by
applying simple selection criteria.


title:
On properness and related properties of quasilinear systems on unbounded
  domains

abstract:
  The purpose of this paper is to provide tools for analyzing the compactness
of sequences in Sobolev spaces, in particular if the sequence gets mapped onto
a compact set by some nonlinear operator. Here, our focus lies on a very
general class of nonlinear operators arising in quasilinear systems of partial
differential equations of second order, in divergence form. Our approach, based
on a suitable decomposition lemma, admits the discussion of problems with some
inherent loss of compactness, for example due to a domain with infinite measure
or a lower order term with critical growth. As an application, we obtain a
characterization of properness which is considerably easier to verify than the
definition. The methods presented can also be used to check Palais--Smale
conditions for variational problems.


title:
On the Road to Understanding Type Ia Progenitors: Precision Simulations
  of Double Degenerate Mergers

abstract:
  We review the current state of the art in double degenerate merger
simulations to better understand the role this phenomenon plays in type Ia
progenitors. Because the fate of a merged system may well depend on the exact
evolution of the matter temperature (as well as mixing of the merged system),
precision simulations are required to determine the true fate of these systems.
Unfortunately, if we compare the results of current simulations, we find
many-order of magnitude differences in quantities like mass-transfer rates in
the merger process. We discuss these differences and outline an approach using
verification and validation that should allow us to achieve a level of
precision sufficient to determine the true fate (thermonuclear vs. collapse) of
double degenerate mergers. Understanding the fate of lower-mass systems (e.g. R
Coronae Borealis stars) may be key in our final testing phase.


title:
Decomposition into weight * level + jump and application to a new
  classification of primes

abstract:
  In this paper we introduce an Euclidean decomposition of elements a_n of an
increasing sequence of natural numbers into weight * level + jump which we use
to classify the numbers a_n either by weight or by level. We then show that
this decomposition can be seen as a generalization of the sieve of Eratosthenes
(which is the particular case of the whole sequence of natural numbers). We
apply this decomposition to prime numbers in order to obtain a new
classification of primes, we analyze a few properties of this classification
and we make a series of conjectures based on numerical data. Finally we show
how composite numbers and 2-almost primes behave under the decomposition.


title:
Gauge Thresholds and Kaehler Metrics for Rigid Intersecting D-brane
  Models

abstract:
  The gauge threshold corrections for globally consistent Z2 x Z2' orientifolds
with rigid intersecting D6-branes are computed. The one-loop corrections to the
holomorphic gauge kinetic function are extracted and the Kaehler metrics for
the charged chiral multiplets are determined up to two constants.


title:
A Comment on the Path Integral Approach to Cosmological Perturbation
  Theory

abstract:
  It is pointed out that the exact renormalization group approach to
cosmological perturbation theory, proposed in Matarrese and Pietroni, JCAP 0706
(2007) 026, arXiv:astro-ph/0703563 and arXiv:astro-ph/0702653, constitutes a
misnomer. Rather, having instructively cast this classical problem into path
integral form, the evolution equation then derived comes about as a special
case of considering how the generating functional responds to variations of the
primordial power spectrum.


title:
Eigenvalue repulsion in an effective theory of SU(2) Wilson lines in
  three dimensions

abstract:
  We perform simulations of an effective theory of SU(2) Wilson lines in three
dimensions. We include a non-perturbative "fuzzy-bag" contribution which is
added to the one-loop perturbative potential for the Wilson line. We confirm
that, at moderately weak coupling, this leads to eigenvalue repulsion in a
finite region above the deconfining phase transition which shrinks in the
extreme weak-coupling limit. A non-trivial Z(N) symmetric vacuum arises in the
confined phase.


title: Massive gravity from descent equations

abstract:
  Both massless and massive gravity are derived from descent equations
(Wess-Zumino consistency conditions). The massive theory is a continuous
deformation of the massless one.


title:
A Monte Carlo Algorithm for Sampling Rare Events: Application to a
  Search for the Griffiths Singularity

abstract:
  We develop a recently proposed importance-sampling Monte Carlo algorithm for
sampling rare events and quenched variables in random disordered systems. We
apply it to a two dimensional bond-diluted Ising model and study the Griffiths
singularity which is considered to be due to the existence of rare large
clusters. It is found that the distribution of the inverse susceptibility has
an exponential tail down to the origin which is considered the consequence of
the Griffiths singularity.


title:
Sheaves on affine Schubert varieties, modular representations and
  Lusztig's conjecture

abstract:
  We relate a certain category of sheaves of k-vector spaces on a complex
affine Schubert variety to modules over the k-Lie algebra (for ch k>0) or to
modules over the small quantum group (for ch k=0) associated to the Langlands
dual root datum. As an application we give a new proof of Lusztig's conjecture
on quantum characters and on modular characters for almost all characteristics.
Moreover, we relate the geometric and representation theoretic sides to sheaves
on the underlying moment graph, which allows us to extend the known instances
of Lusztig's modular conjecture in two directions: We give an upper bound on
the exceptional characteristics and verify its multiplicity one case for all
relevant primes.


title: Half-metallic ferromagnets: From band structure to many-body effects

abstract:
  A review of new developments in theoretical and experimental electronic
structure investigations of half-metallic ferromagnets (HMF) is presented.
Being semiconductors for one spin projection and metals for another ones, these
substances are promising magnetic materials for applications in spintronics
(i.e., spin-dependent electronics). Classification of HMF by the peculiarities
of their electronic structure and chemical bonding is discussed. Effects of
electron-magnon interaction in HMF and their manifestations in magnetic,
spectral, thermodynamic, and transport properties are considered. Especial
attention is paid to appearance of non-quasiparticle states in the energy gap,
which provide an instructive example of essentially many-body features in the
electronic structure. State-of-art electronic calculations for correlated
$d$-systems is discussed, and results for specific HMF (Heusler alloys,
zinc-blende structure compounds, CrO$_{2},$ Fe$_{3}$O$_{4}$) are reviewed.


title:
A conformal approach to numerical calculations of asymptotically flat
  spacetimes

abstract:
  This thesis is concerned with the development and application of conformal
techniques to numerical calculations of asymptotically flat spacetimes. The
conformal compactification technique enables us to calculate spatially
unbounded domains, thereby avoiding the introduction of an artificial timelike
outer boundary. We construct in spherical symmetry an explicit scri-fixing
gauge, i.e. a conformal and a coordinate gauge in which the spatial coordinate
location of null infinity is independent of time so that no resolution loss in
the physical part of the conformal extension appears. Going beyond spherical
symmetry, we develop a method to include null infinity in the computational
domain. With this method, hyperboloidal initial value problems for the Einstein
equations can be solved in a scri-fixing general wave gauge. To study spatial
infinity, we discuss the conformal Gauss gauge and the reduced general
conformal field equations from a numerical point of view. This leads us to the
first numerical calculation of the entire Schwarzschild-Kruskal solution
including spatial, null and timelike infinity and the domain close to the
singularity. After developing a three dimensional, frame based evolution code
with smooth inner and outer boundaries we calculate a radiative axisymmetric
vacuum solution in a neighbourhood of spatial infinity represented as a
cylinder including a piece of null infinity. In this context, a certain
component of the rescaled Weyl tensor representing the radiation field is
calculated unambiguously with respect to an adapted tetrad at null infinity.


title: Infection spreading in a population with evolving contacts

abstract:
  We study the spreading of an infection within an SIS epidemiological model on
a network. Susceptible agents are given the opportunity of breaking their links
with infected agents. Broken links are either permanently removed or
reconnected with the rest of the population. Thus, the network coevolves with
the population as the infection progresses. We show that a moderate
reconnection frequency is enough to completely suppress the infection. A
partial, rather weak isolation of infected agents suffices to eliminate the
endemic state.


title:
Complementarity in atomic (finite-level quantum) systems: an
  information-theoretic approach

abstract:
  We develop an information theoretic interpretation of the number-phase
complementarity in atomic systems, where phase is treated as a continuous
positive operator valued measure (POVM). The relevant uncertainty principle is
obtained as an upper bound on a sum of knowledge of these two observables for
the case of two-level systems. A tighter bound characterizing the uncertainty
relation is obtained numerically in terms of a weighted knowledge sum involving
these variables. We point out that complementarity in these systems departs
from mutual unbiasededness in two signalificant ways: first, the maximum
knowledge of a POVM variable is less than log(dimension) bits; second,
surprisingly, for higher dimensional systems, the unbiasedness may not be
mutual but unidirectional in that phase remains unbiased with respect to number
states, but not vice versa. Finally, we study the effect of non-dissipative and
dissipative noise on these complementary variables for a single-qubit system.


title:
Bayesian nonparametric estimation of the spectral density of a long
  memory Gaussian time series

abstract:
  Let $\mathbf {X}=\{X_t, t=1,2,... \}$ be a stationary Gaussian random
process, with mean $EX_t=\mu$ and covariance function
$\gamma(\tau)=E(X_t-\mu)(X_{t+\tau}-\mu)$. Let $f(\lambda)$ be the
corresponding spectral density; a stationary Gaussian process is said to be
long-range dependent, if the spectral density $f(\lambda)$ can be written as
the product of a slowly varying function $\tilde{f}(\lambda)$ and the quantity
$\lambda ^{-2d}$. In this paper we propose a novel Bayesian nonparametric
approach to the estimation of the spectral density of $\mathbf {X}$. We prove
that, under some specific assumptions on the prior distribution, our approach
assures posterior consistency both when $f(\cdot)$ and $d$ are the objects of
interest. The rate of convergence of the posterior sequence depends in a
significant way on the structure of the prior; we provide some general results
and also consider the fractionally exponential (FEXP) family of priors (see
below). Since it has not a well founded justification in the long memory
set-up, we avoid using the Whittle approximation to the likelihood function and
prefer to use the true Gaussian likelihood.


title: Defects in correlated metals and superconductors

abstract:
  In materials with strong local Coulomb interactions, simple defects such as
atomic substitutions strongly affect both macroscopic and local properties of
the system. A nonmagnetic impurity, for instance, is seen to induce magnetism
nearby. Even without disorder, models of such correlated systems are generally
not soluble in 2 or 3 dimensions, and so few exact results are known for the
properties of such impurities. Nevertheless, some simple physical ideas have
emerged from experiments and approximate theories. Here, we first review what
we can learn about this problem from 1D antiferromagnetically correlated
systems. We then discuss experiments on the high Tc cuprate normal state which
probe the effect of impurities on local charge and spin degrees of freedom, and
compare with theories of single impurities in correlated hosts, as well as
phenomenological effective Kondo descriptions. Subsequently, we review theories
of impurities in d-wave superconductors including residual quasiparticle
interactions, and compare with experiments in the superconducting state. We
argue that existing data exhibit a remarkable similarity to impurity-induced
magnetism in the 1D case, implying the importance of electronic correlations
for the understanding of these phenomena, and suggesting that impurities may
provide excellent probes of the still poorly understood ground state of the
cuprates.


title:
Nonlinearizing linear equations to integrable systems including new
  hierarchies with nonholonomic deformations

abstract:
  We propose a scheme for nonlinearizing linear equations to generate
integrable nonlinear systems of both the AKNS and the KN classes, based on the
simple idea of dimensional analysis and detecting the building blocks of the
Lax pair. Along with the well known equations we discover a novel integrable
hierarchy of higher order nonholonomic deformations for the AKNS family, e.g.
for the KdV, the mKdV, the NLS and the SG equation, showing thus a two-fold
universality of the recently found deformation for the KdV equation.

categories: nlin.SI cond-mat.stat-mech hep-th math-ph math.MP


title: Resolvent and scattering matrix at the maximum of the potential

abstract:
  We study the microlocal structure of the resolvent of the semi-classical
Schrodinger operator with short range potential at an energy which is a unique
non-degenerate global maximum of the potential. We prove that it is a
semi-classical Fourier integral operator quantizing the incoming and outgoing
Lagrangian submanifolds associated to the fixed hyperbolic point. We then
discuss two applications of this result to describing the structure of the
spectral function and the scattering matrix of the Schrodinger operator at the
critical energy.


title:
Partial open book decompositions and the contact class in sutured Floer
  homology

abstract:
  We demonstrate how to combinatorially calculate the EH-class of a compatible
contact structure in the sutured Floer homology group of a balanced sutured
three manifold which is associated to an abstract partial open book
decomposition. As an application we show that every contact three manifold
(closed or with convex boundary) can be obtained by gluing tight contact
handlebodies whose EH-classes are nontrivial.


title: Baryon resonances and strong decays

abstract:
  Constituent quark models provide a reasonable description of the baryon mass
spectra. However, even in the light- and strange-flavor sectors several
intriguing shortcomings remain. Especially with regard to strong decays of
baryon resonances no consistent picture has so far emerged, and the existing
experimental data cannot be explained in a satisfactory manner. Recently first
covariant calculations with modern constituent quark models have become
available for all pi, eta, and K decay modes of the low-lying light and strange
baryons. They generally produced a remarkable underestimation of the
experimental data for partial decay widths. We summarize the main results and
discuss their impact on the classification of baryon resonances into flavor
multiplets. These findings are of particular relevance for future efforts in
the experimental investigation of baryon resonances.


title:
Cosmological parameters from strong gravitational lensing and stellar
  dynamics in elliptical galaxies

abstract:
  We show how the combination of observations related to strong gravitational
lensing and stellar dynamics in ellipticals offers a new way to measure the
cosmological matter and dark-energy density parameters. A gravitational lensing
estimate of the mass enclosed inside the Einstein circle can be obtained by
measuring the Einstein angle, once the critical density of the system is known.
A model-dependent dynamical estimate of this mass can also be obtained by
measuring the central velocity dispersion of the stellar component. By assuming
the well-tested homologous 1/r^{2} profile for the total density distribution
in the lens elliptical galaxies, these two mass measurements can be properly
compared. Thus, a relation between the Einstein angle and the central stellar
velocity dispersion is derived, and the cosmological matter and the dark-energy
density parameters can be estimated from this. We determined the accuracy of
the cosmological parameter estimates by means of simulations that include
realistic measurement uncertainties on the relevant quantities. Interestingly,
the expected constraints on the cosmological parameter plane are complementary
to those coming from other observational techniques. Then, we applied the
method to the data sets of the Sloan Lens ACS and the Lenses Structure and
Dynamics Surveys, and showed that the concordance value between 0.7 and 0.8 for
the dark-energy density parameter is included in our 99% confidence regions.
The small number of lenses available to date prevents us from precisely
determining the cosmological parameters, but it still proves the feasibility of
the method. When applied to samples made of hundreds of lenses that are
expected to become available from forthcoming surveys, this technique will be
an important tool for measuring the geometry of the Universe.


title:
Data-driven wavelet-Fisz methodology for nonparametric function
  estimation

abstract:
  We propose a wavelet-based technique for the nonparametric estimation of
functions contaminated with noise whose mean and variance are linked via a
possibly unknown variance function. Our method, termed the data-driven
wavelet-Fisz technique, consists of estimating the variance function via a
Nadaraya-Watson estimator, and then performing a wavelet thresholding procedure
which uses the estimated variance function and local means of the data to set
the thresholds at a suitable level. We demonstrate the mean-square
near-optimality of our wavelet estimator over the usual range of Besov classes.
To achieve this, we establish an exponential inequality for the Nadaraya-Watson
variance function estimator. We discuss various implementation issues
concerning our wavelet estimator, and demonstrate its good practical
performance. We also show how it leads to a new wavelet-domain data-driven
variance-stabilising transform. Our estimator can be applied to a variety of
problems, including the estimation of volatilities, spectral densities and
Poisson intensities, as well as to a range of problems in which the
distribution of the noise is unknown.


title:
Synchronization of phase oscillators with heterogeneous coupling: A
  solvable case

abstract:
  We consider an extension of Kuramoto's model of coupled phase oscillators
where oscillator pairs interact with different strengths. When the coupling
coefficient of each pair can be separated into two different factors, each one
associated to an oscillator, Kuramoto's theory for the transition to
synchronization can be explicitly generalized, and the effects of coupling
heterogeneity on synchronized states can be analytically studied. The two
factors are respectively interpreted as the weight of the contribution of each
oscillator to the mean field, and the coupling of each oscillator to that
field. We explicitly analyze the effects of correlations between those weights
and couplings, and show that synchronization can be completely inhibited when
they are strongly anti-correlated. Numerical results validate the theory, but
suggest that finite-size effect are relevant to the collective dynamics close
to the synchronization transition, where oscillators become entrained in
synchronized frequency clusters.


title: Slowly Rotating Charged Gauss-Bonnet Black holes in AdS Spaces

abstract:
  Rotating charged Gauss-Bonnet black hole solutions in higher dimensional ($d
>4$), asymptotically anti-de Sitter spacetime are obtained in the small angular
momentum limit. The angular momentum, magnetic dipole moment, and the
gyromagnetic ratio of the black holes are calculated and it turns out that the
Gauss-Bonnet term does not affect to the gyromagnetic ratio.


title: Risk, ambiguity and quantum decision theory

abstract:
  In the present article we use the quantum formalism to describe the effects
of risk and ambiguity in decision theory. The main idea is that the
probabilities in the classic theory of expected utility are estimated
probabilities, and thus do not follow the classic laws of probability theory.
In particular, we show that it is possible to use consistently the classic
expected utility formula, where the probability associated to the events are
computed with the equation of quantum interference. Thus we show that the
correct utility of a lottery can be simply computed by adding to the classic
expected utility a new corrective term, the uncertainty utility, directly
connected with the quantum interference term.


title: The absence of the 4$\psi$ divergence in noncommutative chiral models

abstract:
  In this paper we show that in the noncommutative chiral gauge theories the
4-fermion vertices are finite. The $4\psi$-vertices appear in linear order in
quantization of the $\theta$-expanded noncommutative gauge theories; in all
previously considered models, based on Dirac fermions, the $4\psi$-vertices
were divergent and nonrenormalizable.


title:
Two-dimensional kinematics of SLACS lenses: I. Phase-space analysis of
  the early-type galaxy SDSS J2321-097 at z=0.1

abstract:
  We present the first results of a combined VLT VIMOS integral-field unit and
Hubble Space Telescope (HST)/ACS study of the early-type lens galaxy SDSS
J2321-097 at z=0.0819, extending kinematic studies to a look-back time of 1
Gyr. This system, discovered in the Sloan Lens ACS Survey (SLACS), has been
observed as part of a VLT Large Programme with the goal of obtaining
two-dimensional stellar kinematics of 17 early-type galaxies to z~0.35 and Keck
spectroscopy of an additional dozen lens systems. Bayesian modelling of both
the surface brightness distribution of the lensed source and the
two-dimensional measurements of velocity and velocity dispersion has allowed
us, under the only assumptions of axisymmetry and a two-integral stellar
distribution function (DF) for the lens galaxy, to dissect this galaxy in three
dimensions and break the classical mass--anisotropy, mass-sheet and
inclination--oblateness degeneracies. Our main results are that the galaxy (i)
has a total density profile well described by a single power-law rho propto
r^{-gamma'} with gamma'=2.06^{+0.03}_{-0.06}; (ii) is a very slow rotator
(specific stellar angular momentum parameter lambda_R = 0.075); (iii) shows
only mild anisotropy (delta ~ 0.15); and (iv) has a dark matter contribution of
~30 per cent inside the effective radius. Our first results from this large
combined imaging and spectroscopic effort with the VLT, Keck and HST show that
the structure of massive early-type galaxies beyond the local Universe can now
be studied in great detail using the combination of stellar kinematics and
gravitational lensing. Extending these studies to look-back times where
evolutionary effects become measurable holds great promise for the
understanding of formation and evolution of early-type galaxies.


title: Dipolar bosons in a planar array of one-dimensional tubes

abstract:
  We investigate bosonic atoms or molecules interacting via dipolar
interactions in a planar array of one-dimensional tubes. We consider the
situation in which the dipoles are oriented perpendicular to the tubes by an
external field. We find various quantum phases reaching from a `sliding
Luttinger liquid' phase in which the tubes remain Luttinger liquids to a
two-dimensional charge density wave ordered phase. Two different kinds of
charge density wave order occur: a stripe phase in which the bosons in
different tubes are aligned and a checkerboard phase. We further point out how
to distinguish the occurring phases experimentally.


title: Barrier breakdown in a multiple quantum well structure

abstract:
  We explore a regime of unipolar electronic transport in a multiple quantum
well structure with very large current discontinuities - up to five orders of
magnitude. Magneto-transport experiments reveal different transport regimes.
Quantum well impact ionization shifts the structure from a resistive down
state, where the current flows through inter-well quantum tunneling, to a
highly conductive up state. In the latter regime, the current leaks through a
barrier suddenly broken down because of an efficient ionization of the first
quantum well.


title:
The blue plume population in dwarf spheroidal galaxies: young stellar
  population or genuine blue stragglers?

abstract:
  In the context of dwarf spheroidal galaxies it is hard to firmly disentangle
a genuine Blue Stragglers (BSS) population from a normal young main (MS)
sequence. This difficulty is persistent. For a sample of 9 non-star forming
Local Group dwarf galaxies we compute the ``BSS frequency'' and compare it with
that found in the Milky Way globular/open clusters and halo. The comparison
shows that the BSS-frequency in dwarf galaxies, at any given Mv, is always
higher than that in globular clusters of similar luminosities. Moreover, the
estimated BSS-frequency for the lowest luminosity dwarf galaxies is in
excellent agreement with that observed in the Milky Way halo and open clusters.
We conclude that the low density, almost collision-less environment, of our
dwarf galaxy sample point to their very low dynamical evolution and consequent
negligible production of collisional BSS.


title:
Routing in Outer Space: Improved Security and Energy-Efficiency in
  Multi-Hop Wireless Networks

abstract:
  In this paper we consider security-related and energy-efficiency issues in
multi-hop wireless networks. We start our work from the observation, known in
the literature, that shortest path routing creates congested areas in multi-hop
wireless networks. These areas are critical--they generate both security and
energy efficiency issues. We attack these problems and set out routing in outer
space, a new routing mechanism that transforms any shortest path routing
protocol (or approximated versions of it) into a new protocol that, in case of
uniform traffic, guarantees that every node of the network is responsible for
relaying the same number of messages, on expectation. We can show that a
network that uses routing in outer space does not have congested areas, does
not have the associated security-related issues, does not encourage selfish
positioning, and, in spite of using more energy globally, lives longer of the
same network using the original routing protocol.


title:
Application of information and complexity theories to public opinion
  polls. The case of Greece (2004-2007)

abstract:
  A general methodology to study public opinion inspired from information and
complexity theories is outlined. It is based on probabilistic data extracted
from opinion polls. It gives a quantitative information-theoretic explanation
of high job approval of Greek Prime Minister Mr. Constantinos Karamanlis
(2004-2007), while the same time series of polls conducted by the company
Metron Analysis showed that his party New Democracy (abbr. ND) was slightly
higher than the opposition party of PASOK -party leader Mr. George Papandreou.
It is seen that the same mathematical model applies to the case of the
popularity of President Clinton between January 1998 and February 1999,
according to a previous study, although the present work extends the
investigation to concepts as complexity and Fisher information, quantifying the
organization of public opinion data.


title: The Kochen-Specker Theorem Revisited in Quantum Measure Theory

abstract:
  The Kochen-Specker Theorem is widely interpreted to imply that non-contextual
hidden variable theories that agree with the predictions of Copenhagen quantum
mechanics are impossible. The import of the theorem for a novel observer
independent interpretation of quantum mechanics, due to Sorkin, is
investigated.


title: On the unitary nature of abelian conformal blocks

abstract:
  We determine the projectively flat unitary structure on abelian conformal
blocks in terms of WZW-data.


title: Stable reduction of curves and tame ramification

abstract:
  We study stable reduction of curves in the case where a tamely ramified base
extension is sufficient. If X is a smooth curve defined over the fraction field
of a strictly henselian discrete valuation ring, there is a criterion, due to
T. Saito, that describes precisely, in terms of the geometry of the minimal
model with strict normal crossings of X, when a tamely ramified extension
suffices in order for X to obtain stable reduction. For such curves we
construct an explicit extension that realizes the stable reduction, and we
furthermore show that this extension is minimal. We also obtain purely
geometric proof of Saito's criterion, avoiding the use of vanishing cycles.


title: On sets represented by partitions

abstract:
  We prove a lemma that is useful to get upper bounds for the number of
partitions without a given subsum. From this we can deduce an improved upper
bound for the number of sets represented by the (unrestricted or into unequal
parts) partitions of an integer n.


title: Monomial bases related to the n! conjecture

abstract:
  The purpose of this paper is to find a new way to prove the $n!$ conjecture
for particular partitions. The idea is to construct a monomial and explicit
basis for the space $M_{\mu}$. We succeed completely for hook-shaped
partitions, i.e., $\mu=(K+1,1^L)$. We are able to exhibit a basis and to verify
that its cardinality is indeed $n!$, that it is linearly independent and that
it spans $M_{\mu}$. We derive from this study an explicit and simple basis for
$I_{\mu}$, the annihilator ideal of $\Delta_{\mu}$. This method is also
successful for giving directly a basis for the homogeneous subspace of
$M_{\mu}$ consisting of elements of 0 $x$-degree.


title: Bases explicites et conjecture n!

abstract:
  The aim of this work is to construct a monomial and explicit basis for the
space $M_{\mu}$ relative to the $n!$ conjecture. We succeed completely for
hook-shaped partitions, i.e. $\mu=(K+1,1^L)$. We are indeed able to exhibit a
basis and to verify that its cardinality is $n!$, that it is linearly
independent and that it spans $M_{\mu}$. We deduce from this study an explicit
and simple basis for $I_{\mu}$, the annulator ideal of $\Delta_{\mu}$. This
method is also successful for giving directly a basis for the homogeneous
subspace of $M_{\mu}$ consisting of elements of 0 $x$-degree.


title: On certain spaces of lattice diagram polynomials

abstract:
  The aim of this work is to study some lattice diagram determinants
$\Delta_L(X,Y)$. We recall that $M_L$ denotes the space of all partial
derivatives of $\Delta_L$. In this paper, we want to study the space
$M^k_{i,j}(X,Y)$ which is defined as the sum of $M_L$ spaces where the lattice
diagrams $L$ are obtained by removing $k$ cells from a given partition, these
cells being in the ``shadow'' of a given cell $(i,j)$ in a fixed Ferrers
diagram. We obtain an upper bound for the dimension of the resulting space
$M^k_{i,j}(X,Y)$, that we conjecture to be optimal. This dimension is a
multiple of $n!$ and thus we obtain a generalization of the $n!$ conjecture.
Moreover, these upper bounds associated to nice properties of some special
symmetric differential operators (the ``shift'' operators) allow us to
construct explicit bases in the case of one set of variables, i.e. for the
subspace $M^k_{i,j}(X)$ consisting of elements of 0 $Y$-degree.


title:
A Route to Robust Double Pulse Excitability in Optically Injected
  Semiconductor Lasers

abstract:
  We present and analyse a three-dimensional model for a quantum dot
semiconductor laser with optical injection. This model describes recent
experimental single and double excitable intensity pulses, which are related to
a central saddle-node homoclinic bifurcation as in the Adler equation. Double
pulses are related to a period doubling bifurcation and occur on the same
homoclinic curve as single pulses. The bifurcation scenario consolidating
single and double excitable pulses is described in detail.


title: On certain spaces of lattice diagram determinants

abstract:
  The aim of this work is to study some lattice diagram polynomials
$\Delta_D(X,Y)$. We recall that $M_D$ denotes the space of all partial
derivatives of $\Delta_D$. In this paper, we want to study the space
$M^k_{i,j}(X,Y)$ which is the sum of $M_D$ spaces where the lattice diagrams
$D$ are obtained by removing $k$ cells from a given partition, these cells
being in the ``shadow'' of a given cell $(i,j)$ of the Ferrers diagram. We
obtain an upper bound for the dimension of the resulting space
$M^k_{i,j}(X,Y)$, that we conjecture to be optimal. These upper bounds allow us
to construct explicit bases for the subspace $M^k_{i,j}(X)$ consisting of
elements of 0 $Y$-degree.


title:
A Possible New Distance Indicator -Correlation between the duration and
  the X-ray luminosity of the shallow decay phase of Gamma Ray Bursts-

abstract:
  We investigated the characteristics of the shallow decay phase in the early
Xray afterglows of GRBs observed by Swift X-Ray Telescope (XRT) during the
period of January 2005 to December 2006. We found that the intrinsic break time
at the shallow-to-normal decay transition in the X-ray light curve Tbrk^0 is
moderately well correlated with the isotropic X-ray luminosity in the end of
the shallow decay phase (LX,end) as Tbrk^0 = (9.39+/-0.64)*10^3s(LX,end/10^47
ergs/s)^(-0.71+/-0.03), while Tbrk^0 is weakly correlated with the isotropic
gamma-ray energy of the prompt emission Egamma,iso. Using Tbrk^0 - LX,end
relation we have determined the pseudo redshifts of 33 GRBs. We compared the
pseudo redshifts of 11 GRBs with measured redshifts and found the rms error to
be 0.17 in log z. From this pseudo redshift, we estimate that ~15% of the Swift
GRBs have z > 5. The advantages of this distance indicator is that (1) it
requires only X-ray afterglow data while other methods such as Amati and
Yonetoku correlations require the peak energy (Ep) of the prompt emission, (2)
the redshift is uniquely determined without redshift degeneracies unlike the
Amati correlation, and (3) the redshift is estimated in advance of deep
follow-ups so that possible high redshift GRBs might be selected for detailed
observations.


title:
A continuous spectrum for nonhomogeneous differential operators in
  Orlicz-Sobolev spaces

abstract:
  We study the nonlinear eigenvalue problem $-{\rm div}(a(|\nabla u|)\nabla
u)=\lambda|u|^{q(x)-2}u$ in $\Omega$, $u=0$ on $\partial\Omega$, where $\Omega$
is a bounded open set in $\RR^N$ with smooth boundary, $q$ is a continuous
function, and $a$ is a nonhomogeneous potential. We establish sufficient
conditions on $a$ and $q$ such that the above nonhomogeneous quasilinear
problem has continuous families of eigenvalues. The proofs rely on elementary
variational arguments. The abstract results of this paper are illustrated by
the cases $a(t)=t^{p-2}\log (1+t^r)$ and $a(t)= t^{p-2} [\log (1+t)]^{-1}$.


title: Ideals and quotients of B-quasisymmetric functions

abstract:
  The space $QSym_n(B)$ of $B$-quasisymmetric polynomials in 2 sets of $n$
variables was recently studied by Baumann and Hohlweg. The aim of this work is
a study of the ideal $<QSym_n(B)^+>$ generated by $B$-quasisymmetric
polynomials without constant term. In the case of the space $QSym_n$ of
quasisymmetric polynomials in 1 set of $n$ variables, Aval, Bergeron and
Bergeron proved that the dimension of the quotient of the space of polynomials
by the ideal $<QSym_n^+>$ is given by Catalan numbers $C_n=\frac 1 {n+1} {2n
\choose n}$. In the case of $B$-quasisymmetric polynomials, our main result is
that the dimension of the analogous quotient is equal to
$\frac{1}{2n+1}{3n\choose n}$, the numbers of ternary trees with $n$ nodes. The
construction of a Gr\"obner basis for the ideal, as well as of a linear basis
for the quotient are interpreted by a bijection with lattice paths. These
results are finally extended to $p$ sets of variables, and the dimension is in
this case $\frac{1}{pn+1}{(p+1)n\choose n}$, the numbers of $p$-ary trees with
$n$ nodes.