title: D-brane superpotentials and RG flows on the quintic

abstract:
  The behaviour of D2-branes on the quintic under complex structure
deformations is analysed by combining Landau-Ginzburg techniques with methods
from conformal field theory. It is shown that the boundary renormalisation
group flow induced by the bulk deformations is realised as a gradient flow of
the effective space time superpotential which is calculated explicitly to all
orders in the boundary coupling constant.


title: Wormholes as Black Hole Foils

abstract:
  We study to what extent wormholes can mimic the observational features of
black holes. It is surprisingly found that many features that could be thought
of as ``characteristic'' of a black hole (endowed with an event horizon) can be
closely mimicked by a globally static wormhole, having no event horizon. This
is the case for: the apparently irreversible accretion of matter down a hole,
no-hair properties, quasi-normal-mode ringing, and even the dissipative
properties of black hole horizons, such as a finite surface resistivity equal
to 377 Ohms. The only way to distinguish the two geometries on an
observationally reasonable time scale would be through the detection of
Hawking's radiation, which is, however, too weak to be of practical relevance
for astrophysical black holes. We point out the existence of an interesting
spectrum of quantum microstates trapped in the throat of a wormhole which could
be relevant for storing the information ``lost'' during a gravitational
collapse.


title: Supervised Feature Selection via Dependence Estimation

abstract:
  We introduce a framework for filtering features that employs the
Hilbert-Schmidt Independence Criterion (HSIC) as a measure of dependence
between the features and the labels. The key idea is that good features should
maximise such dependence. Feature selection for various supervised learning
problems (including classification and regression) is unified under this
framework, and the solutions can be approximated using a backward-elimination
algorithm. We demonstrate the usefulness of our method on both artificial and
real world datasets.


title: Effect of premelting on conductivity of DNA-lipid films

abstract:
  We have measured temperature dependent (between 20 and 80 C) electrical
conductivity and molecular structure (Raman spectroscopy) of DNA-lipid cast
film. Our findings show that the conductivity is strongly influenced by
premelting effects in the molecular structure starting near physiological
temperatures (~40 C), prior to the global DNA denaturation.


title: D.E.U.S. (Dimension Embedded in Unified Symmetry)

abstract: An unified model of the Universe, Black Holes, particles .... and beyond.


title:
Correlation of macroscopic instability and Lyapunov times in the general
  three-body problem

abstract:
  We conducted extensive numerical experiments of equal mass three-body systems
until they became disrupted. The system lifetimes, as a bound triple, and the
Lyapunov times show a correlation similarto what has been earlier obtained for
small bodies in the Solar System. Numerical integrations of several sets of
differently randomised initial conditions produced the same relationship of the
instability time and Lyapunov time. Marginal probability densities of the
various times in the three-body experiments are also discussed. Our high
accuracy numerical method for three-body orbit computations and Lyapunov time
determinations is concisely described.


title:
Study of B+ to p Lambdabar gamma, p Lambdabar pi0 and B0 to p Lambdabar
  pi-

abstract:
  We study the charmless baryonic three-body decays of B mesons: B+ to p
Lambdabar gamma, B+ to p Lambdabar pi0 and B0 to p Lambdabar pi-. The partial
branching fractions as a function of the baryon-antibaryon mass and the polar
angle distributions of the proton in the baryon-antibaryon system are
presented. This study includes the first observation of B+ to p Lambdabar pi0,
which is measured to have a branching fraction of (3.00^{+0.61}_{-0.53}\pm
0.33) times 10^{-6}. We also set upper limits on branching fractions of the
two-body decays B0 to p Sigmabar^{*-}, B0 to Delta^0 Lambdabar, B+ to p
Sigmabar^{*0}, and B+ to Delta^+ Lambdabar at the 90% confidence level. These
results are obtained from a 414fb^{-1} data sample collected near the
Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+
e- collider.


title: Chiral symmetry and the string description of excited hadrons

abstract:
  A large symmetry group is perhaps experimentally observed in excited hadrons
which includes the chiral group U(2)_L x U(2)_R as a subgroup. To possess this
large symmetry a dynamical model for excited hadrons, presumably a string
model, should explain formation of chiral multiplets and, at the same time,
predict coinciding slopes of the angular and radial Regge trajectories. This is
possible only if both the dynamics of the string and the chirality of the
quarks at the ends of the string are considered together. We construct a
model-independent unitary transformation from the relativistic chiral basis to
the ^{2S+1}L_J basis, commonly used in hadronic phenomenology as well as in the
string models, and demonstrate that a hadron belonging to the given chiral
representation is a fixed superposition of the basis vectors with different L's
and S's. Thus the description of highly excited hadron in terms of a fixed L is
not compatible with chiral symmetry and has to be disregarded in favour of the
description in terms of the total hadron spin J. Therefore, dynamics of the
string must deliver the principal quantum number ~n+J, in order chiral
multiplets with different spins to become degenerate, as required by the large
symmetry group.


title: First integrals for non linear hyperbolic equations

abstract:
  Given a solution of a nonlinear wave equation on the flat space-time (with a
real analytic nonlinearity), we relate its Cauchy data at two different times
by nonlinear representation formulas in terms of asymptotic series. We first
show how to construct formally these series by mean of generating functions
based on an algebraic framework inspired by the construction of Fock spaces in
quantum field theory. Then we build an analytic setting in which all these
constructions really make sense and give rise to convergent series.


title: The isospin symmetry breaking effects in $K_{e4}$ decays

abstract:
  The Fermi-Watson theorem is generalized to the case of two coupled channels
with different masses and applied to final state interaction in $K_{e4}$
decays. The impact of considered effect on the phase of the $\pi\pi$ scattering
is estimated and shown that it can be crucial for scattering lengths extraction
from experimental data on $K_{e4}$ decays.


title: CP Violation Studies at Tevatron

abstract:
  We present an overview of a few recent results related to CP-violation from
the Tevatron. First, we discuss a measurement of the dimuon charge asymmetry
from D{\O}that extracts the CP-violation parameter of $\Bo$ mixing and decay.
This is followed by the CDF measurement of the CP-violating asymmetry in
$\bdkpi$ decays. Finally we give the CDF result on the ratio $R = \frac{BR(B
\to D^0 K)}{BR(B \to D^0 \pi)}$


title: Entanglement induced Sub-Planck structures

abstract:
  We study Wigner function of a system describing entanglement of two
cat-states. Quantum interferece arising due to entanglement is shown to produce
sub-Planck structures in the phase-space plots of the Wigner function. Origin
of these structures in our case depends on entanglement unlike those in Zurek
\cite{Zurek}. It is argued that the entangled cat-states are better suited for
carrying out precision measurements.


title: X-ray and Sunyaev-Zel'dovich scaling relations in galaxy clusters

abstract:
  [Abridged] We present an analysis of the scaling relations between X-ray
properties and Sunyaev-Zel'dovich (SZ) parameters for a sample of 24 X-ray
luminous galaxy clusters observed with Chandra and with measured SZ effect.
These objects are in the redshift range 0.14--0.82 and have X-ray bolometric
luminosity L>10^45 erg/s. We perform a spatially resolved spectral analysis and
recover the density, temperature and pressure profiles of the ICM, just relying
on the spherical symmetry of the cluster and the hydrostatic equilibrium
hypothesis. We observe that the correlations among X-ray quantities only are in
agreement with previous results obtained for samples of high-z X-ray luminous
galaxy clusters. On the relations involving SZ quantities, we obtain that they
correlate with the gas temperature with a logarithmic slope significantly
larger than the predicted value from the self-similar model. The measured
scatter indicates, however, that the central Compton parameter y_0 is a proxy
of the gas temperature at the same level of other X-ray quantities like
luminosity. Our results on the X-ray and SZ scaling relations show a tension
between the quantities more related to the global energy of the system (e.g.
gas temperature, gravitating mass) and the indicators of the structure of the
ICM (e.g. gas density profile, central Compton parameter y_0), showing the most
significant deviations from the values of the slope predicted from the
self-similar model in the L-T, L-M_{tot}, M_{gas}-T, y_0-T relations. When the
slope is fixed to the self-similar value, these relations consistently show a
negative evolution suggesting a scenario in which the ICM at higher redshift
has lower both X-ray luminosity and pressure in the central regions than the
expectations from self-similar model.


title:
On the Applications of a New Technique to Solve Linear Differential
  Equations, with and without Source

abstract:
  A general method for solving linear differential equations of arbitrary
order, is used to arrive at new representations for the solutions of the known
differential equations, both without and with a source term. A new
quasi-solvable potential has also been constructed taking recourse to the above
method.


title: A Channel that Heats Up

abstract:
  Motivated by on-chip communication, a channel model is proposed where the
variance of the additive noise depends on the weighted sum of the past channel
input powers. For this channel, an expression for the capacity per unit cost is
derived, and it is shown that the expression holds also in the presence of
feedback.


title: Cool objects: From SED fitting to age estimation

abstract:
  The physical properties of almost any kind of astronomical object can be
derived by fitting synthetic spectra or photometry extracted from theoretical
models to observational data. This process usually involves working with
multiwavelength data, which is one of the cornerstones of the VO philosophy.
  From this kind of studies, when combining with theoretical isochrones one can
even estimate ages. We present here the results obtained from a code designed
to perform chi^2 tests to both spectroscopic models (or the associated
synthetic photometry) and combinations of blackbodies (including modified
blackbodies). Some steps in this process can already be done in a VO
environment, and the rest are in the process of development. We must note that
this kind of studies in star forming regions, clusters, etc. produce a huge
amount of data, very tedious to analyze using the traditional methodology. This
make them excellent examples where to apply the VO capabilities.


title: Electron-electron correlation in graphite

abstract:
  The full three dimensional dispersion of the pi-bands, Fermi velocities and
effective masses are measured with angle resolved photoemission spectroscopy
and compared to first-principles calculations. The band structure by
density-functional theory strongly underestimates the slope of the bands and
the trigonal warping effect. Including electron-electron calculation on the
level of the GW approximation, however, yields remarkable agreement in the
vicinity of the Fermi level. This demonstrates the breakdown of the independent
electron picture in semi-metallic graphite and points towards a pronounced role
of electron correlation for the interpretation of transport experiments and
double-resonant Raman scattering for a wide range of carbon based materials.


title:
A relativistic gauge theory of nonlinear quantum mechanics and Newtonian
  gravity

abstract:
  A new kind of gauge theory is introduced, where the minimal coupling and
corresponding covariant derivatives are defined in the space of functions
pertaining to the functional Schroedinger picture of a given field theory.
While, for simplicity, we study the example of a U(1) symmetry, this kind of
gauge theory can accommodate other symmetries as well. We consider the
resulting relativistic nonlinear extension of quantum mechanics and show that
it incorporates gravity in the (0+1)-dimensional limit, similar to recently
studied Schroedinger-Newton equations. Gravity is encoded here into a universal
nonlinear extension of quantum theory. A probabilistic interpretation (Born's
rule) holds, provided the underlying model is scale free.
  Keywords: nonlinear functional Schroedinger equation, gauge symmetry,
Newtonian gravity.


title:
Effects of Lepton Flavour Violation on Chargino Production at the Linear
  Collider

abstract:
  We study the effects of lepton flavour violation (LFV) on the production
processes e+e- --> \chi+_i \chi-_j at a linear collider with longitudinal e+
and e- beam polarizations. In the case of LFV the sneutrino mass eigenstates
have no definite flavour, therefore, in the t-channel more than one sneutrino
mass eigenstate can contribute to the chargino production cross sections. Our
framework is the Minimal Supersymmetric Standard Model (MSSM) including LFV
terms. We show that in spite of the restrictions on the LFV parameters due to
the current limits on rare lepton decays, the cross section \sigma(e+e- -->
\chi+_1 \chi-_1) can change by a factor of 2 or more when varying the LFV
mixing angles. We point out that even if the present bound on BR(tau- --> e-
gamma) improves by a factor of thousand the influence of LFV on the chargino
production cross section can be significant. These results could have an
important impact on the strategies for determining the underlying model
parameters at the linear collider.


title:
PdBI sub-arcsecond study of the SiO microjet in HH212 - Origin and
  collimation of Class 0 jets

abstract:
  The bipolar HH 212 outflow has been mapped in SiO using the extended
configuration of the Plateau de Bure Interferometer (PdBI), revealing a highly
collimated SiO jet closely associated with the H2 jet component. We study at
unprecedented resolution (0.34" across the jet axis) the properties of the
innermost SiO ``microjet'' within 1000 AU of this young Class 0 source, to
compare it with atomic microjets from more evolved sources and to constrain its
origin. The SiO channel maps are used to investigate the microjet collimation
and velocity structure. A large velocity gradient analysis is applied to SiO
(2-1), (5-4) and (8-7) data from the PdBI and the Submillimeter Array to
constrain the SiO opacity and abundance. The HH212 Class 0 microjet shows
striking similarities in collimation and energetic budget with atomic microjets
from T Tauri sources. Furthermore, the SiO lines appear optically thick, unlike
what is generally assumed. We infer T(kin) ~ 50-500 K and an SiO/H2 abundance
greater than 4 10(-8)-6 10(-5) for n(H2) = 10(7)-10(5) cm(-3), i.e. 0.05-90% of
the elemental silicon. This similar jet width, regardless of the presence of a
dense envelope, definitely rules out jet collimation by external pressure, and
favors a common MHD self-collimation (and possibly acceleration) process at all
stages of star formation. We propose that the more abundant SiO in Class 0 jets
could mainly result from rapid (less than 25 yrs) molecular synthesis at high
jet densities.


title:
Self-organization processes in laser system with nonlinear absorber and
  external force influence

abstract:
  We discuss mechanisms of self-organization processes in two-level solid-state
class-B laser system. The model is considered under assumptions of influence of
nonlinear absorber and external force, separately. It was found that
self-organization occurs through the Hopf bifurcation and results to a stable
pulse radiation. Analysis is performed according to the Floquet exponent
investigation. It was found that influence of the nonlinear absorber extends
the domain of control parameters that manage a stable periodic radiation
processes. An external force suppresses self-organization processes. A combined
influence of both external force and nonlinear absorber results to more
complicated picture of self-organization with two reentrant Hopf bifurcations.


title:
Equilibrium and absolute minimal states of Mumford-Shah functionals and
  brittle fracture propagation

abstract:
  By a combination of geometrical and configurational analysis we study the
properties of absolute minimal and equilibrium states of general Mumford-Shah
functionals, with applications to models of quasistatic brittle fracture
propagation. The main results concern the mathematical relations between
physical quantities as energy release rate and energy concentration for 3D
cracks with complex shapes, seen as outer measures living on the crack edge.


title:
Classification of line-transitive point-imprimitive linear spaces with
  line size at most 12

abstract:
  In this paper we complete a classification of finite linear spaces $\cS$ with
line size at most 12 admitting a line-transitive point-imprimitive subgroup of
automorphisms. The examples are the Desarguesian projective planes of orders
$4,7, 9$ and 11, two designs on 91 points with line size 6, and 467 designs on
729 points with line size 8.


title:
Mass loss from Luminous Blue Variables and Quasi-Periodic Modulations of
  Radio Supernovae

abstract:
  Massive stars, supernovae (SNe), and long-duration gamma-ray bursts (GRBs)
have a huge impact on their environment. Despite their importance, a
comprehensive knowledge of which massive stars produce which SN/GRB is hitherto
lacking. We present a brief overview about our knowledge of mass loss in the
Hertzsprung-Russell Diagram (HRD) covering evolutionary phases of the OB main
sequence, the unstable Luminous Blue Variable (LBV) stage, and the Wolf-Rayet
(WR) phase. Despite the fact that metals produced by ``self-enrichment'' in WR
atmospheres exceed the initial -- host galaxy -- metallicity, by orders of
magnitude, a particularly strong dependence of the mass-loss rate on the
initial metallicity is found for WR stars at sub-solar metallicities (1/10 --
1/100 solar). This provides a significant boost to the collapsar model for
GRBs, as it may present a viable mechanism to prevent the loss of angular
momentum by stellar winds at low metallicity, whilst strong Galactic WR winds
may inhibit GRBs occurring at solar metallicities. Furthermore, we discuss
recently reported quasi-sinusoidal modulations in the radio lightcurves of SNe
2001ig and 2003bg. We show that both the sinusoidal behaviour and the
recurrence timescale of these modulations are consistent with the predicted
mass-loss behaviour of LBVs, and we suggest LBVs may be the progenitors of some
core-collapse SNe.


title:
Constraining GRB progenitor models by probing Wolf-Rayet wind geometries
  in the Large Magellanic Cloud

abstract:
  The favoured progenitors of long-duration gamma-ray bursts (GRBs) are rapidly
rotating Wolf-Rayet (WR) stars. However, most Galactic WR stars are slow
rotators, as stellar winds are thought to remove angular momentum. This poses a
challenge to the collapsar model. Recent observations indicate that GRBs occur
predominately in low metallicity (Z) environments, which may resolve the
problem: lower Z leads to less mass loss, which may inhibit angular momentum
removal, allowing WR stars to remain rotating rapidly until collapse. We wish
to determine whether low Z WR stars rotate on average more rapidly than
Galactic WR stars, and perform a Very Large Telescope (VLT) linear
spectropolarimetry survey of WR stars in the low Z environment of the Large
Magellanic Cloud (LMC) and compare our results with the Galactic sample. We
find that only 2 out of 13 (i.e. 15%) of LMC WR stars show line polarization
effects, compared to a similarly low fraction of ~15-20% for Galactic WR stars.
The low incidence of line polarization effects in LMC WR stars suggests that
the threshold metallicity where significant differences in WR rotational
properties occur is below that of the LMC (Z ~ 0.5 Zsun), possibly constraining
GRB progenitor channels to this upper metallicity.


title: Thin Lead Titanate films grown by Molecular Beam Epitaxy

abstract:
  The growth of atomically-flat thin films of ferroelectric PbTiO3 on SrTiO3
substrates, using molecular beam epitaxy, is reported. The main issue in the
growth of these materials is the high volatility of lead. This can be largely
overcome by using PbO, instead of Pb, as a source and by using atomic oxygen
during growth. The continuous decrease of the out-of-plane lattice parameter
with increasing temperature in the investigated range, indicates that PbTiO3 is
still ferroelectric at the growth temperature (Tg= 600oC), which agrees with
the theoretical prediction of TC= 765oC (compared to TCbulk= 490oC) for the
present mismatch strain values.


title:
Quantisations of piecewise affine maps on the torus and their quantum
  limits

abstract:
  For general quantum systems the semiclassical behaviour of eigenfunctions in
relation to the ergodic properties of the underlying classical system is quite
difficult to understand. The Wignerfunctions of eigenstates converge weakly to
invariant measures of the classical system, the so called quantum limits, and
one would like to understand which invariant measures can occur that way,
thereby classifying the semiclassical behaviour of eigenfunctions. We introduce
a class of maps on the torus for whose quantisations we can understand the set
of quantum limits in great detail. In particular we can construct examples of
ergodic maps which have singular ergodic measures as quantum limits, and
examples of non-ergodic maps where arbitrary convex combinations of absolutely
continuous ergodic measures can occur as quantum limits. The maps we quantise
are obtained by cutting and stacking.


title: GREGOR: the New German Solar Telescope

abstract:
  GREGOR is a new open solar telescope with an aperture of 1.5m. It replaces
the former 45-cm Gregory Coude telescope on the Canary island Tenerife. The
optical concept is that of a double Gregory system. The main and the elliptical
mirrors are made from a silicon-carbide material with high thermal
conductivity. This is important to keep the mirrors on the ambient temperature
avoiding local turbulence. GREGOR will be equipped with an adaptive optics
system. The new telescope will be ready for operation in 2008. Post-focus
instruments in the first stage will be a spectrograph for polarimetry in the
near infrared and a 2-dimensional spectrometer based on Fabry-Perot
interferometers for the visible.


title: Determining factors behind the PageRank log-log plot

abstract:
  We study the relation between PageRank and other parameters of information
networks such as in-degree, out-degree, and the fraction of dangling nodes. We
model this relation through a stochastic equation inspired by the original
definition of PageRank. Further, we use the theory of regular variation to
prove that PageRank and in-degree follow power laws with the same exponent. The
difference between these two power laws is in a multiple coefficient, which
depends mainly on the fraction of dangling nodes, average in-degree, the power
law exponent, and damping factor. The out-degree distribution has a minor
effect, which we explicitly quantify. Our theoretical predictions show a good
agreement with experimental data on three different samples of the Web.


title: Electronic structure of barium titanate : an abinitio DFT study

abstract:
  First principle calculations were performed to study the ground state
electronic properties of Barium titanate within the density functional theory
(DFT). In our DFT computations, we used Vosko-Wilk-Nusair correlation energy
functional and generalized gradient approximation (GGA) exchange and
correlation energy functional as suggested by Perdew and Wang (PWGGA). The band
structure, total density of states (DOS) and partial DOS have been
systematically conducted to investigate the electronic configuration of this
prototype ferroelectric perovskits compound. The band gap was 1.92 eV within
our approach, and the quasi-flat band at -17 eV and -10 eV were attributed to
the O 2s and Ba 5p states respectively, which was in good agreement with the
corresponding total DOS and partial DOS. From the DOS investigation, it can be
seen that the Ti eg state intended to interact with the oxygen octahedral
orbitals to form the p-d hybridization. Moreover the strong p-d overlap and
bonding can be observed in the electronic density redistribution along the
different crystalline planes with respect to the corresponding space group, and
the electronic isodense have been shown along the (001), (100), (110) and (111)
crystal planes. From these electronic density maps, the strong bonding between
Ti and O atoms can even be observed in the (111) crystalline plane.


title: Classification of Supersymmetric Lattice Gauge Theories by Orbifolding

abstract:
  We provide a general classification of supersymmetric lattice gauge theories
that can be obtained from orbifolding of theories with four and eight
supercharges. We impose at least one preserved supercharge on the lattice and
Lorentz invariance in the naive continuum limit. Starting with four
supercharges, we obtain one two-dimensional lattice gauge theory, identical to
the one already given in the literature. Starting with eight supercharges, we
obtain a unique three-dimensional lattice gauge theory and infinitely many
two-dimensional lattice theories. They can be classified according to seven
distinct groups, five of which have two preserved supercharges while the others
have only one.


title: On matrix type corings, algebra coverings and Cech cohomology

abstract:
  We investigate the a matrix-type coring associated to a complete covering of
an algebra, its Amitsur complex and propose a definition for the related Cech
cohomology relative to the covering.


title: The 1 keV to 200 keV X-ray Spectrum of NGC 2992 and NGC 3081

abstract:
  The Seyfert 2 galaxies NGC 2992 and NGC 3081 have been observed by INTEGRAL
and Swift. We report about the results and the comparison of the spectrum above
10 keV based on INTEGRAL IBIS/ISGRI, Swift/BAT, and BeppoSAX/PDS. A spectrum
can be extracted in the X-ray energy band ranging from 1 keV up to 200 keV.
Although NGC 2992 shows a complex spectrum below 10 keV, the hard tail observed
by various missions exhibits a slope with photon index = 2, independent on the
flux level during the observation. No cut-off is detectable up to the detection
limit around 200 keV. In addition, NGC 3081 is detected in the INTEGRAL and
Swift observation and also shows an unbroken Gamma = 1.8 spectrum up to 150
keV. These two Seyfert galaxies give further evidence that a high-energy
cut-off in the hard X-ray spectra is often located at energies E_C >> 100 keV.
In NGC 2992 a constant spectral shape is observed over a hard X-ray luminosity
variation by a factor of 11. This might indicate that the physical conditions
of the emitting hot plasma are constant, while the amount of plasma varies, due
to long-term flaring activity.


title: Uncovering the topology of configuration space networks

abstract:
  The configuration space network (CSN) of a dynamical system is an effective
approach to represent the ensemble of configurations sampled during a
simulation and their dynamic connectivity. To elucidate the connection between
the CSN topology and the underlying free-energy landscape governing the system
dynamics and thermodynamics, an analytical soluti on is provided to explain the
heavy tail of the degree distribution, neighbor co nnectivity and clustering
coefficient. This derivation allows to understand the universal CSN network
topology observed in systems ranging from a simple quadratic well to the native
state of the beta3s peptide and a 2D lattice heteropolymer. Moreover CSN are
shown to fall in the general class of complex networks describe d by the
fitness model.


title: The aqueous and crystalline forms of L-alanine zwitterion

abstract:
  The structural properties of L-alanine amino acid in aqueous solution and in
crystalline phase have been studied by means of density-functional
electronic-structure and molecular dynamics simulations. The solvated
zwitterionic structure of L-alanine (+NH3-C2H4-COO-) was systematically
compared to the structure of its zwitterionic crystalline analogue acquired
from both computer simulations and experiments. It turns out that the
structural properties of an alanine molecule in aqueous solution can differ
significantly from those in crystalline phase, these differences being mainly
attributed to hydrogen bonding interactions. In particular, we found that the
largest difference between the two alanine forms can be seen for the
orientation and bond lengths of the carboxylate (COO-) group: in aqueous
solution the C-O bond lengths appear to strongly correlate with the number of
water molecules which form hydrogen bonds with the COO- group. Furthermore, the
hydrogen bond lengths are shorter and the hydrogen bond angles are larger for
L-alanine in water as compared to crystal. Overall, our findings strongly
suggest that the generally accepted approach of extending the structural
information acquired from crystallographic data to a L-alanine molecule in
aqueous solution should be used with caution.


title: Twisted Dirac Operators over Quantum Spheres

abstract:
  We construct new families of spectral triples over quantum spheres, with a
particular attention focused on the standard Podles quantum sphere and twisted
Dirac operators.


title:
Semiclassical theory of ballistic transport through chaotic cavities
  with spin-orbit interaction

abstract:
  We investigate the influence of spin-orbit interaction on ballistic transport
through chaotic cavities by using semiclassical methods. Our approach is based
on the Landauer formalism and the Fisher-Lee relations, appropriately
generalized to spin-orbit interaction, and a semiclassical representation of
Green functions. We calculate conductance coefficients by exploiting ergodicity
and mixing of suitably combined classical spin-orbit dynamics, and making use
of the Sieber-Richter method and its most recent extensions. That way we obtain
weak anti-localization and confirm previous results obtained in the symplectic
ensemble of Random Matrix Theory.


title:
Photoelectric phenomena in structures based on high-resistivity
  semiconductor crystals with a thin insulator layer at the semiconductor-metal
  boundary

abstract:
  A previously unknown effect-giant spatial redistribution of the electric
field strength in a crystal under illumination of the structure - was
discovered and investigated in real photoresistors on high-resistivity
(semi-insulating) semiconductor CdTe crystals (in metal-thin insulator-
semiconductor-thin insulator -metal structures).
  A new concept is proposed for photoelectric phenomena in high- resistivity
semiconductor crystals. The concept is based on the idea that the
redistribution of the field under such conditions that the carrier lifetime
remains unchanged under illumination plays a determining role in these
phenomena. The nature of the effect is described, the dependence of the
characteristics of the structures on the parameters of the crystal and the
insulator layers is explained by the manifestation of this effect, and ways to
produce structures with prescribed photoelectric characteristics for new
devices and scientific methods are examined.


title:
Gas-grain chemistry in cold interstellar cloud cores with a microscopic
  Monte Carlo approach to surface chemistry

abstract:
  AIM: We have recently developed a microscopic Monte Carlo approach to study
surface chemistry on interstellar grains and the morphology of ice mantles. The
method is designed to eliminate the problems inherent in the rate-equation
formalism to surface chemistry. Here we report the first use of this method in
a chemical model of cold interstellar cloud cores that includes both gas-phase
and surface chemistry. The surface chemical network consists of a small number
of diffusive reactions that can produce molecular oxygen, water, carbon
dioxide, formaldehyde, methanol and assorted radicals. METHOD: The simulation
is started by running a gas-phase model including accretion onto grains but no
surface chemistry or evaporation. The starting surface consists of either flat
or rough olivine. We introduce the surface chemistry of the three species H, O
and CO in an iterative manner using our stochastic technique. Under the
conditions of the simulation, only atomic hydrogen can evaporate to a
significant extent. Although it has little effect on other gas-phase species,
the evaporation of atomic hydrogen changes its gas-phase abundance, which in
turn changes the flux of atomic hydrogen onto grains. The effect on the surface
chemistry is treated until convergence occurs. We neglect all non-thermal
desorptive processes. RESULTS: We determine the mantle abundances of assorted
molecules as a function of time through 2x10^5 yr. Our method also allows
determination of the abundance of each molecule in specific monolayers. The
mantle results can be compared with observations of water, carbon dioxide,
carbon monoxide, and methanol ices in the sources W33A and Elias 16. Other than
a slight underproduction of mantle CO, our results are in very good agreement
with observations.


title: Chemical Properties of Star Forming Dwarf Galaxies

abstract:
  Recent studies of the near-infrared (NIR) properties of dwarf irregular
galaxies (dIs) and blue compact dwarfs (BCDs) have provided improved estimates
for the NIR luminosity of old stellar populations in these galaxies. These can
be used to derive gas fractions, and thereby to evaluate how BCDs have evolved
with respect to dIs. Oxygen abundances have been derived for four BCDs in the
Virgo Cluster from a run at Gemini-North in 2003. Combining these new
abundances with published values, we study the correlations among the
metallicity, Ks luminosity, gas mass, baryonic mass, and gas fraction. Within
errors, the two types of dwarfs appear to share a common relation between the
oxygen abundance and the luminosity in Ks. The correlation between metallicity
and the gas fraction is the same for BCDs as for dIs, indicating that BCD
evolution has been similar to dIs. Since dIs appear to have evolved as isolated
systems, the BCD bursts are unlikely to be a consequence of gas infall or
merging.


title: The Dynamical Discrete Web

abstract:
  The dynamical discrete web (DDW), introduced in recent work of Howitt and
Warren, is a system of coalescing simple symmetric one-dimensional random walks
which evolve in an extra continuous dynamical parameter s. The evolution is by
independent updating of the underlying Bernoulli variables indexed by discrete
space-time that define the discrete web at any fixed s. In this paper, we study
the existence of exceptional (random) values of s where the paths of the web do
not behave like usual random walks and the Hausdorff dimension of the set of
such exceptional s. Our results are motivated by those about exceptional times
for dynamical percolation in high dimension by H\"aggstrom, Peres and Steif,
and in dimension two by Schramm and Steif. The exceptional behavior of the
walks in DDW is rather different from the situation for dynamical random walks
of Benjamini, H\"aggstrom, Peres and Steif. In particular, we prove that there
are exceptional values of s for which the walk from the origin S^s(n) has
limsup S^s(n)/\sqrt n \leq K with a nontrivial dependence of the Hausdorff
dimension on K. We also discuss how these and other results extend to the
dynamical Brownian web, a natural scaling limit of DDW. The scaling limit is
the focus of a paper in preparation; it was studied by Howitt and Warren and is
related to the Brownian net of Sun and Swart.


title: Spin-String Interaction in QCD Strings

abstract:
  I consider the question of the interaction between a QCD string and the spin
of a quark or an antiquark on whose worldline the string terminates. The
problem is analysed from the point of view of a string representation for the
expectation value of a Wilson loop for a spin-half particle. A string
representation of the super Wilson loop is obtained starting from an effective
string representation of a Wilson Loop. The action obtained in this manner is
invariant under a worldline supersymmetry and has a boundary term which
contains the spin-string interaction. For rectangular loops the spin-string
interaction vanishes and there is no spin-spin term in the resulting heavy
quark potential. On the other hand if an allowance is made for the finite
intrinsic thickness of the flux-tube, by assuming that the spin-string
interaction takes place not just at the boundary of the string world-sheet but
extends to a distance of the order of the intrinsic thickness of the flux tube,
then we do obtain a spin-spin interaction which falls as the fifth power of the
distance. Such a term was previously suggested by Kogut and Parisi in the
context of a flux-tube model of confinement.


title: Computation of Atomic Fibers of Z-Linear Maps

abstract:
  For given matrix $A\in\Z^{d\times n}$, the set $P_{b}=\{z:Az=b,z\in\Z^n_+\}$
describes the preimage or fiber of $b\in\Z^d$ under the $\Z$-linear map
$f_A:\Z^n_+\to\Z^d$, $x\mapsto Ax$. The fiber $P_{b}$ is called atomic, if
$P_{b}=P_{b_1}+P_{b_2}$ implies $b=b_1$ or $b=b_2$. In this paper we present a
novel algorithm to compute such atomic fibers. An algorithmic solution to
appearing subproblems, computational examples and applications are included as
well.


title:
Resonant relaxation near a massive black hole: the dependence on
  eccentricity

abstract:
  The orbits of stars close to a massive black hole are nearly Keplerian
ellipses. Such orbits exert long term torques on each other, which lead to an
enhanced angular momentum relaxation known as resonant relaxation. Under
certain conditions, this process can modify the angular momentum distribution
and affect the interaction rates of the stars with the massive black hole more
efficiently than non-resonant relaxation. The torque on an orbit exerted by the
cluster depends on the eccentricity of the orbit. In this paper, we calculate
this dependence and determine the resonant relaxation timescale as a function
of eccentricity. In particular, we show that the component of the torque that
changes the magnitude of the angular momentum is linearly proportional to
eccentricity, so resonant relaxation is much more efficient on eccentric orbits
than on circular orbits.


title: Six New ZZ Ceti Stars from the SPY and the HQS Surveys

abstract:
  We report on the discovery of six new ZZ Ceti stars. They were selected as
candidates based on preparatory photometric observations of objects from the
Hamburg Quasar Survey (HQS), and based on the spectra of the Supernova Ia
Progenitor Survey (SPY). Time-series photometry of 19 candidate stars was
carried out at the Nordic Optical Telescope (NOT) at Roque de Los Muchachos
Observatory, Spain. The new variables are relatively bright, 15.4<B<16.6. Among
them is WD1150-153, which is the third ZZ Ceti star that shows photospheric
CaII in its spectrum.


title: Zipf law in the popularity distribution of chess openings

abstract:
  We perform a quantitative analysis of extensive chess databases and show that
the frequencies of opening moves are distributed according to a power-law with
an exponent that increases linearly with the game depth, whereas the pooled
distribution of all opening weights follows Zipf's law with universal exponent.
We propose a simple stochastic process that is able to capture the observed
playing statistics and show that the Zipf law arises from the self-similar
nature of the game tree of chess. Thus, in the case of hierarchical
fragmentation the scaling is truly universal and independent of a particular
generating mechanism. Our findings are of relevance in general processes with
composite decisions.


title:
Dynamics of meromorphic functions with direct or logarithmic
  singularities

abstract:
  We show that if a meromorphic function has a direct singularity over
infinity, then the escaping set has an unbounded component and the intersection
of the escaping set with the Julia set contains continua. This intersection has
an unbounded component if and only if the function has no Baker wandering
domains. We also give estimates of the Hausdorff dimension and the upper box
dimension of the Julia set of a meromorphic function with a logarithmic
singularity over infinity. The above theorems are deduced from more general
results concerning functions which have "direct or logarithmic tracts", but
which need not be meromorphic in the plane. These results are obtained by using
a generalization of Wiman-Valiron theory. The method is also applied to complex
differential equations.


title: Tverberg's theorem with constraints

abstract:
  The topological Tverberg theorem claims that for any continuous map of the
(q-1)(d+1)-simplex to R^d there are q disjoint faces such that their images
have a non-empty intersection. This has been proved for affine maps, and if $q$
is a prime power, but not in general.
  We extend the topological Tverberg theorem in the following way: Pairs of
vertices are forced to end up in different faces. This leads to the concept of
constraint graphs. In Tverberg's theorem with constraints, we come up with a
list of constraints graphs for the topological Tverberg theorem.
  The proof is based on connectivity results of chessboard-type complexes.
Moreover, Tverberg's theorem with constraints implies new lower bounds for the
number of Tverberg partitions. As a consequence, we prove Sierksma's conjecture
for $d=2$, and $q=3$.


title: On the formation of gyration-like excitations in solid solutions

abstract:
  Measurements of thermal excitations of V-O and Y-Ba-Cu-O solid solutions have
been performed by a method of inelastic neutron scattering for low-energy
transfers range. Features at energy transfer about 3meV and about 5meV for V-O
and Y-Ba-Cu-O accordingly were observed in neutron scattering spectra. The
reason of appearance of the observed low-energy excitations are the formation
of an effective potential of oxygen with broad weakly upwards bottom at the xy
plane of tetragonal symmetry octahedron, which the interstitial atom occupies.
The experimental observed features can be understood in the representation of
hindered quantum gyration of the interstitial atom. It was assumed that O1 and
O4 atoms in Y-Ba-Cu-O, as well as in V-O system, are in two-dimensional
quantum-well, which has almost flat bottom formed by the surrounding atoms Cu
and Ba. The possibility of formation of collective excitations of gyration-type
as a result of exchange interaction of light atoms in matrix lattice is
considered. The assumption is made that the existence of gyration-like
excitations can play an important role for explanation of some phenomena in
solid state physics, in particular in realization of high values of
temperatures of superconducting transitions in high temperature
superconductors.


title: Multidimensional SDE with anticipating initial process and reflection

abstract:
  In this paper, the strong solutions $ (X, L)$ of multidimensional stochastic
differential equations with reflecting boundary and possible anticipating
initial random variables is established. The key is to obtain some substitution
formula for Stratonovich integrals via a uniform convergence of the
corresponding Riemann sums and to prove continuity of functionals of $ (X, L)$.


title: Constructing a quadrilateral inside another one

abstract:
  Connect each vertex of a convex quadrilateral Q to the midpoint of the next
(proceeding counterclockwise) side. The four connecting lines create an
interior quadrilateral I. We study the ratio area(I)/area(Q). We also determine
what happens to area(I)/area(Q) when the four midpoints are replaced by points
which divide the sides in the ratio of rho to (1-rho) proceeding clockwise.
Here rho is any fixed number satisfying 0 < rho < 1.


title: Two Dimensional Quantum (4,4) Null Superstring in de Sitter Space

abstract:
  The (4,4) null superstring equations of motions and constraints on de Sitter
space are given by using the harmonic superspace. These are solved explicitly
by performing a perturbative expansion of the (4,4) superstring coordinates in
powers of c2, the world-sheet speed of light. The analytic expressions of the
zeroth and first order solutions are determined. On the other hand, we study
the quantization of the (4,4)null superstring in de Sitter space and we
describe its superalgebra.


title: Cosmic Ray Origin and Propagation Model

abstract:
  It is presumed that the observed cosmic rays up to about $3\times 10^{18}$ eV
are of Galactic origin, the particles being the ones which are found in the
composition of the stellar winds of stars that explode as supernova into the
interstellar medium (ISM) or into their winds. These particles are accelerated
in the supernova shock. In order to obtain the observed cosmic ray spectrum it
is necessary to take into account the diffusive losses in the Galaxy (which are
making the energy spectrum more steeper). Another modification of the source
spectrum is due to the fragmentation (spallation) of the cosmic ray particles,
after their collision with the ISM atoms. In this paper we are proving that
some particles are injected in the supernova shock one or two time ionized,
and, also, that the contribution of massive stars ($30 M_{\odot}\leq M\leq 50
M_{\odot}$) accelerated particles to cosmic rays (where the winds are highly
enriched in heavy elements) is 1:2 for elements with $Z\geq 6$. Another goal of
this paper is to check if the particles are injected with the same velocity,
energy or momentum.


title:
The white dwarf luminosity function --II. The effect of the measurement
  errors and other biases

abstract:
  Only the 1/V_max method has been employed so far for observationally
determining the white dwarf luminosity function, whereas for other kind of
luminosity functions several other methods have been frequently used. Moreover,
the procedures to determine the white dwarf luminosity function are not free of
biases. These biases have two different origins: they can either be of
statistical nature or a consequence of the measurement errors. In a previous
paper we carried out an in-depth study of the first category of biases for
several luminosity function estimators. In this paper we focus on the biases
introduced by the measurement errors and on the effects of the degree of
contamination of the input sample used to build the disc white dwarf luminosity
function by different kinematical populations. To assess the extent of these
biases we use a Monte Carlo simulator to generate a controlled synthetic
population and analyse the behaviour of the disc white dwarf luminosity
function for several assumptions about the magnitude of the measurement errors
and for several degrees of contamination, comparing the performances of the
most robust luminosity function estimators under such conditions.


title:
Application of energy and angular momentum balance to gravitational
  radiation reaction for binary systems with spin-orbit coupling

abstract:
  We study gravitational radiation reaction in the equations of motion for
binary systems with spin-orbit coupling, at order (v/c)^7 beyond Newtonian
gravity, or O(v/c)^2 beyond the leading radiation reaction effects for
non-spinning bodies. We use expressions for the energy and angular momentum
flux at infinity that include spin-orbit corrections, together with an
assumption of energy and angular momentum balance, to derive equations of
motion that are valid for general orbits and for a class of coordinate gauges.
We show that the equations of motion are compatible with those derived earlier
by a direct calculation.


title: Half-vortices in polariton condensates

abstract:
  It is shown that vortices in linearly polarized polariton condensates in
planar semiconductor microcavities carry two winding numbers (k,m). These
numbers can be either integer or half-integer simultaneously. Four half-integer
vortices (1/2,1/2), (-1/2,-1/2), (1/2,-1/2), and (-1/2,1/2) are anisotropic,
possess the smallest energy, and define the Kosterlitz-Thouless transition
temperature. The condensate concentration remains finite within the core of
half-vortex and the polarization becomes fully circular in the core center.


title: Multi-epoch VLBA observations of 3C 66A

abstract:
  We present the results of six-epoch Very Long Baseline Array (VLBA)
observations of 3C~66A. The high-resolution Very Long Baseline Interferometer
(VLBI) maps obtained at multi-frequency (2.3, 8.4, and 22.2 GHz) simultaneously
enabled us to identify the brightest compact component with the core. We find
that the spectrum of the core can be reasonably fitted by the synchrotron
self-absorption model. Our VLBA maps show that the jet of 3C~66A has two
bendings at about 1.2 and 4 mas from the core. We also give possible
identifications of our jet components with the components in previous VLBA
observations by analysing their proper motions. We find consistent differences
of the position from the core in one component between different frequencies at
six epochs.


title: Two Generator Subalgebras of Lie Algebras

abstract:
  J. G. Thompson showed that a finite group G is solvable if and only if every
two -generated subgroup is solvable. Recently, Grunevald, Kunyavskii, Nikolova,
and Plotkin have shown that the analogue holds for finite-dimensional Lie
algebras over infinite fields of characteristic greater than 5. It is a natural
question to ask to what extent the two-generated subalgebras determine the
structure of the algebra. It is to this question that this paper is addressed.
Here, we consider the classes of strongly-solvable and of supersolvable Lie
algebras, and the property of triangulability.


title:
Neutrino beams as a probe of the nuclear isospin and spin-isospin
  excitations

abstract:
  We explore the possibility of performing nuclear structure studies using low
energy neutrino beams. In particular, low energy beta-beams and conventional
sources (muon decay-at-rest) are considered. We present results on the total
charged-current as well as flux-averaged cross sections associated to electron
(anti)-neutrino scattering on oxygen, iron, molybdenum and lead, as typical
examples. It is shown that by using neutrinos from low energy beta-beams,
information on forbidden states, in particular the spin-dipole, could be
extracted.


title:
Exploiting Heavy Tails in Training Times of Multilayer Perceptrons: A
  Case Study with the UCI Thyroid Disease Database

abstract:
  The random initialization of weights of a multilayer perceptron makes it
possible to model its training process as a Las Vegas algorithm, i.e. a
randomized algorithm which stops when some required training error is obtained,
and whose execution time is a random variable. This modeling is used to perform
a case study on a well-known pattern recognition benchmark: the UCI Thyroid
Disease Database. Empirical evidence is presented of the training time
probability distribution exhibiting a heavy tail behavior, meaning a big
probability mass of long executions. This fact is exploited to reduce the
training time cost by applying two simple restart strategies. The first assumes
full knowledge of the distribution yielding a 40% cut down in expected time
with respect to the training without restarts. The second, assumes null
knowledge, yielding a reduction ranging from 9% to 23%.


title:
Cumulants and large deviations of the current through non-equilibrium
  steady states

abstract:
  Using a generalisation of the detailed balance for systems maintained out of
equilibrium by contact with 2 reservoirs at unequal temperatures or at unequal
densities, we recover the fluctuation theorem for the large deviation funtion
of the current. For large diffusive systems, we show how the large deviation
funtion of the current can be computed using a simple additivity principle. The
validity of this additivity principle and the occurence of phase transitions
are discussed in the framework of the macroscopic fluctuation theory.


title: Complex quotients by nonclosed groups and their stratifications

abstract:
  We define the notion of complex stratification by quasifolds and show that
such spaces occur as complex quotients by certain nonclosed subgroups of tori
associated to convex polytopes. The spaces thus obtained provide a natural
generalization to the nonrational case of the notion of toric variety
associated with a rational convex polytope.


title:
An automated system for lung nodule detection in low-dose computed
  tomography

abstract:
  A computer-aided detection (CAD) system for the identification of pulmonary
nodules in low-dose multi-detector helical Computed Tomography (CT) images was
developed in the framework of the MAGIC-5 Italian project. One of the main
goals of this project is to build a distributed database of lung CT scans in
order to enable automated image analysis through a data and cpu GRID
infrastructure. The basic modules of our lung-CAD system, a dot-enhancement
filter for nodule candidate selection and a neural classifier for
false-positive finding reduction, are described. The system was designed and
tested for both internal and sub-pleural nodules. The results obtained on the
collected database of low-dose thin-slice CT scans are shown in terms of free
response receiver operating characteristic (FROC) curves and discussed.


title: Spherically symmetric spacetimes in f(R) gravity theories

abstract:
  We study both analytically and numerically the gravitational fields of stars
in f(R) gravity theories. We derive the generalized Tolman-Oppenheimer-Volkov
equations for these theories and show that in metric f(R) models the
Parameterized Post-Newtonian parameter $\gamma_{\rm PPN} = 1/2$ is a robust
outcome for a large class of boundary conditions set at the center of the star.
This result is also unchanged by introduction of dark matter in the Solar
System. We find also a class of solutions with $\gamma_{\rm PPN} \approx 1$ in
the metric $f(R)=R-\mu^4/R$ model, but these solutions turn out to be unstable
and decay in time. On the other hand, the Palatini version of the theory is
found to satisfy the Solar System constraints. We also consider compact stars
in the Palatini formalism, and show that these models are not inconsistent with
polytropic equations of state. Finally, we comment on the equivalence between
f(R) gravity and scalar-tensor theories and show that many interesting Palatini
f(R) gravity models can not be understood as a limiting case of a
Jordan-Brans-Dicke theory with $\omega \to -3/2$.


title:
Resonant decompositions and the I-method for cubic nonlinear Schrodinger
  on R^2

abstract:
  The initial value problem for the cubic defocusing nonlinear Schr\"odinger
equation $i \partial_t u + \Delta u = |u|^2 u$ on the plane is shown to be
globally well-posed for initial data in $H^s (\R^2)$ provided $s>1/2$. The
proof relies upon an almost conserved quantity constructed using multilinear
correction terms. The main new difficulty is to control the contribution of
resonant interactions to these correction terms. The resonant interactions are
significant due to the multidimensional setting of the problem and some
orthogonality issues which arise.


title:
Global structure and physical interpretation of the Fonarev solution for
  a scalar field with exponential potential

abstract:
  We discuss the physical interpretation of a dynamical and inhomogeneous
spherically symmetric solution obtained by Fonarev for a scalar field with an
exponential potential. There is a single parameter $w$ in the solution which
can be set to $\pm1$ if it is non-zero, in addition to the steepness parameter
$\lambda$ in the potential. The spacetime is conformally static and
asymptotically flat Friedmann-Robertson-Walker spacetime. The solution reduces
to the Friedmann-Robertson-Walker solution for $w=0$. There are two curvature
singularities, of which one is a timelike central singularity and the other is
a big-bang or big-crunch type singularity. Depending on the parameters, the
spacetime can possess a future outer trapping horizon in the collapsing case.
Then the solution represents a dynamical black hole in the sense of Hayward
although there is a locally naked singularity at the center and no black-hole
event horizon. This demonstrates a weak point of the local definition of a
black hole in terms of a trapping horizon.


title: Brauer Algebras of Simply Laced Type

abstract:
  The diagram algebra introduced by Brauer that describes the centralizer
algebra on tensor products of the natural representation of an orthogonal group
has a presentation by generators and relations that only depends on the graph
of type An on n nodes. Here we describe an algebra depending on an arbitrary
graph of type M. We study its structure when the type is An, Dn, E6, E7, E8. We
determine the representations and find the dimensions. The algebra is
generically semisimple and contains the group algebra of the Coxeter type M as
a subalgebra. It is a ring homomorphism of the Birman-Murakami-Wenzl algebra of
these types. This fact will be used in later work determining the structure of
Birman-Murakami-Wenzl algebras of simply laced spherical type.


title:
The order of the decay of the hole probability for Gaussian random
  SU(m+1) polynomials

abstract:
  We show that for Gaussian random SU(m+1) polynomials of a large degree N the
probability that there are no zeros in the disk of radius r is less than
$e^{-c_{1,r} N^{m+1}}$, and is also greater than $e^{-c_{2,r} N^{m+1}}$.
Enroute to this result, we also derive a more general result: probability
estimates for the event where the volume of the zero set of a random polynomial
of high degree deviates significantly from its mean.


title: A Cohen-Macaulay algebra has only finitely many semidualizing modules

abstract:
  We prove the result stated in the title, which answers the equicharacteristic
case of a question of Vasconcelos.


title:
Charge Polarization Effects and Hole Spectra Characteristics in
  Alxgai-xN/Gan Superlattices

abstract:
  We study the effects of charge polarization on the extended physical
properties of superlattices, such as transmission coefficients and valence band
structure. We consider both linear and parabolic modulation of the band edge.
Based on the theory of finite periodic systems (TFPS), analytic expressions and
high precision calculations of the relevant physical quantities for n-cell
systems are obtained. New and also well-known features of these systems are
identified. Besides the well-known energy bandstructure, we also have the field
bandstructure, with interesting characteristics.Wider field gaps at stronger
internal electric fields and higher density of field bands for larger layer
widths are some of these characteristics. Well denned level density asymmetries
identify the minibands induced by charge polarization or the so-called Quantum
Confining Stark Effect. We present the n-cell transmission amplitudes,
transmission coefficients and miniband structures for different values of the
relevant parameters.


title: Twin Paradox and Causality

abstract:
  After pointing out the historical avatar at the origin of a would be twin or
clock paradox, we argue that, at least on a local scale, the (re-qualified)
paradox is but a necessary consequence of the sole principle of causality.


title: INTEGRAL high energy detection of the transient IGR J11321-5311

abstract:
  Context: The transient hard X-ray source IGR J11321-5311 was discovered by
INTEGRAL on June 2005, during observations of the Crux spiral arm. To date,
this is the only detection of the source to be reported by any X/gamma-ray
mission. Aims: To characterize the behaviour and hence the nature of the source
through temporal and spectral IBIS analysis. Methods: Detailed spectral and
temporal analysis has been performed using standard INTEGRAL software OSA
v.5.1. Results: To date, IGR J11321-5311 has been detected only once. It was
active for about 3.5 hours, a short and bright flare lasting about 1.5 hours is
evident in the IBIS light curve. It reached a peak flux of about 80 mCrab or
2.2x10E-9 erg cmE-2 sE-1 (20--300 keV),corresponding to a peak luminosity of
1.1x10E37 erg sE-1 (assuming a distance of 6.5 kpc). During the outburst, the
source was detected with a significance of 18 sigma (20--300 keV) and 8 sigma
(100--300 keV). The spectrum of the total outburst activity (17--300 keV) is
best fitted by the sum of a power law (Gamma=0.55+/-0.18) plus a black body
(kT=1.0{+0.2}_{-0.3} keV), with no evidence for a break up to 300 keV. A
spectral analysis at Science Window level revealed an evident hardening of the
spectrum through the outburst. The IBIS data were searched for pulsations with
no positive result. Conclusions: The X-ray spectral shape and the flaring
behaviour favour the hypothesis that IGR J11321-5311 is an Anomalous X-ray
Pulsar, though a different nature can not be firmly rejected at the present
stage.


title: Dark Matter Searche with GLAST

abstract:
  The Gamma-Ray Large Area Space Telescope (GLAST), scheduled to be launched in
fall 2007, is the next generation satellite for high-energy gamma-ray
astronomy. The Large Area Telescope (LAT),
  GLAST main instrument, with a wide field of view (> 2 sr), a large effective
area (> 8000 cm^2 at 1 GeV) and 20 MeV - 300 GeV energy range, will provide
excellent high energy gamma-ray observations for Dark Matter searches. In this
paper we examine the potential of the LAT to detect gamma-rays coming from
WIMPS annihilation in the context of supersymmetry. As an example, two search
regions are investigated: the galactic center and the galactic satellites.


title:
Evidence for decay of spin-waves above the pseudogap in underdoped
  YBa2Cu3O6.35

abstract:
  The magnetic spectrum at high-energies in heavily underdoped
YBa$_{2}$Cu$_{3}$O$_{6.35}$ (T$_{c}$=18 K) has been determined throughout the
Brillouin zone. At low-energy the scattering forms a cone of spin excitations
emanating from the antiferromagnetic (0.5, 0.5) wave vector with an acoustic
velocity similar to that of insulating cuprates. At high energy transfers,
below the maximum energy of 270 meV at (0.5, 0), we observe zone boundary
dispersion much larger and spectral weight loss more extensive than in
insulating antiferromagnets. Moreover we report phenomena not found in
insulators, an overall lowering of the zone-boundary energies and a large
damping of $\sim$ 100 meV of the spin excitations at high-energies. The energy
above which the damping occurs coincides approximately with the gap determined
from transport measurements. We propose that as the energy is raised the spin
excitations encounter an extra channel of decay into particle-hole pairs of a
continuum that we associate with the pseudogap.


title:
Relativistic stabilisation of the diocotron instability in a pulsar
  "cylindrical" electrosphere

abstract:
  In a previous work, we showed that the differentially rotating equatorial
disk in the pulsar's electrosphere is diocotron unstable in the
non-relativistic regime. In this paper, we extend these results and study the
relativistic and electromagnetic stabilisation effects by including the
magnetic field perturbation and allow for relativistic speeds of the guiding
centre, in a self-consistent manner. We use the electric drift approximation,
valid for low-density plasmas.
  We linearise the coupled relativistic cold-fluid and Maxwell equations in the
electric drift approximation. The non-linear eigenvalue problem for the
perturbed azimuthal electric field is solved numerically with standard technics
for boundary value problems like the shooting method. The spectrum of the
relativistic diocotron instability in a non-neutral plasma column confined
between two cylindrically conducting walls is computed.
  For low-speed motions, we recover the eigenfunctions and eigenspectra of the
non-relativistic diocotron instability. Our algorithm is also checked in the
relativistic planar diode geometry for which an analytical expression of the
dispersion relation is known. As expected, when the relativistic and
electromagnetic effects become significant, the diocotron instability tends to
stabilise. In cylindrical geometry, for some special rotation profile, all
azimuthal modes $l$ are completely suppressed for sufficiently relativistic
flows. However, for the profile relevant to the electrosphere, depending on the
exact rotation curves, the growth rates can either significantly decrease till
they vanish or persist for moderate $l$.


title: Near-infrared polarimetric study of the bipolar nebula IRAS 19312+1950

abstract:
  We obtained H-band polarimetric data of IRAS 19312+1950 using the
near-infrared camera (CIAO) on the 8 m Subaru telescope. In order to
investigate the physical properties of the central star and the nebula, we
performed dust radiative transfer modeling and compared the model results with
the observed spectral energy distributions (SEDs), the radial profiles of the
total intensity image, and the fraction of linear polarization map. The total
intensity image shows a nearly spherical core with ~3" radius, an S-shaped arm
extending ~10" in the northwest to southeast direction, and an extended lobe
towards the southwest. The polarization map shows a centro-symmetric vector
alignment in almost the entire nebula and low polarizations along the S-shaped
arm. These results suggest that the nebula is accompanied by a central star,
and the S-shaped arm has a physically ring-like structure. From our radiative
transfer modeling, we estimated the stellar temperature, the bolometric
luminosity, and the current mass-loss rate to be 2800 K, 7000 L_sun, and
5.3x10^{-6} M_sun yr^{-1}, respectively. Taking into account previous
observational results, such as the detection of SiO maser emissions and
silicate absorption feature in the 10 $\mu$m spectrum, our dust radiative
transfer analysis based on our NIR imaging polarimetry suggests that (1) the
central star of IRAS 19312+1950 is likely to be an oxygen-rich, dust-enshrouded
AGB star and (2) most of the circumstellar material originates from other
sources (e.g. ambient dark clouds) rather than as a result of mass loss from
the central star.


title: Biordered superconductivity and strong pseudogap state

abstract:
  Interrelation between the two-particle and mean-field problems is used to
describe the strong pseudogap and superconducting states in cuprates. We
present strong pseudogap state as off-diagonal short-range order (ODSRO)
originating from quasi-stationary states of the pair of repulsing particles
with large total momentum (K - pair). Phase transition from the ODSRO state
into the off-diagonal long-range ordered (ODLRO) superconducting state is
associated with Bose-Einstein condensation of the K - pairs. A checkerboard
spatial order observable in the superconducting state in the cuprates is
explained by a rise of the K - pair density wave. A competition between the
ODSRO and ODLRO states leads to the phase diagram typical of the cuprates.
Biordered superconducting state of coexisting condensates of Cooper pairs with
zero momentum and K - pairs explains some properties of the cuprates observed
below Tc: Drude optical conductivity, unconventional isotope effect and two-gap
quasiparticle spectrum with essentially different energy scales.


title: The Birman-Murakami-Algebras Algebras of Type Dn

abstract:
  The Birman-Murakami-Wenzl algebra (BMW algebra) of type Dn is shown to be
semisimple and free of rank (2^n+1)n!!-(2^(n-1)+1)n! over a specified
commutative ring R, where n!! is the product of the first n odd integers. We
also show it is a cellular algebra over suitable ring extensions of R. The
Brauer algebra of type Dn is the image af an R-equivariant homomorphism and is
also semisimple and free of the same rank, but over the polynomial ring Z with
delta and its inverse adjoined. A rewrite system for the Brauer algebra is used
in bounding the rank of the BMW algebra above. As a consequence of our results,
the generalized Temperley-Lieb algebra of type Dn is a subalgebra of the BMW
algebra of the same type.


title: Nahm transform and parabolic minimal Laplace transform

abstract:
  We prove that Nahm transform for integrable connections with a finite number
of regular singularities and an irregular singularity of rank 1 on the Riemann
sphere is equivalent -- up to considering integrable connections as holonomic
$\D$-modules -- to minimal Laplace transform. We assume semi-simplicity and
resonance-freeness conditions, and we work in the framework of objects with a
parabolic structure. In particular, we describe the definition of the parabolic
version of Laplace transform due to C. Sabbah. The proof of the main result
relies on the study of a twisted de Rham complex.


title:
Pioneer Anomaly and Accelerating Universe as Effects of the Minkowski
  Space Conformal Symmetry

abstract:
  On the basis of the nonisometric transformations subgroup of the SO(4.2)
group, the nonlinear time inhomogeneity one-parameter conformal transformations
are constructed. The connection between the group parameter and the Hubble
constant H0 is established. It is shown that the existence of an anomalous
blue-shifted frequency drift is a pure kinematic manifestation of the time
inhomogeneity induced by the Universe expansion. This conclusion is confirmed
via a generalization of the standard Special Relativity clock synchronization
procedure to the space expanding case. The obtained formulae are in accordance
with the observable Pioneer Anomaly effect. The anomalous blue-shifted drift is
universal, does not depend on the presence of graviting centers and can be, in
principle, observed on any frequencies under suitable experimental conditions.
The explicit analytic expression for the speed of recession--intergalactic
distance ratio is obtained in the form of a function of the red shift z valid
in the whole range of its variation. In the small z limit this expression
exactly reproduces the Hubble law. The maximum value of this function at
z=0.475 quantitatively corresponds to the experimentally found value z(exp) =
0.46 +/- 0.13 of the transition from the decelerated to the accelerated
expansion of the Universe.


title:
Intermediate regime in Tetrathiafulvalene-Chloranil (TTF-CA)
  pressure-induced neutral-ionic transition

abstract:
  We report a detailed spectroscopic study of the pressure induced
neutral-ionic phase transition (NIT) of the mixed-stack charge-transfer (CT)
crystal tetrathiafulvalene-chloranil (TTF-CA). We show that the pressure
induced phase transition is still first-order and involves the presence of an
intermediate disordered phase, defined by the coexistence of two species of
different ionicity. Further application of pressure gradually converts this
phase into an homogeneous ferroelectric phase with a single ionicity. In
addition, we detect strong pretransitional phenomena which anticipate the
intermediate phase and are indicative of a precursor dynamic regime dominated
by fluctuations.


title: On the stratified dust distribution of the GG Tau circumbinary ring

abstract:
  Our objective is to study the vertical dust distribution in the circumbinary
ring of the binary system GG Tau and to search for evidence of stratification,
one of the first steps expected to occur during planet formation.
  We present a simultaneous analysis of four scattered light images spanning a
range of wavelength from 800 nm to 3800 nm and compare them with (i) a
parametric prescription for the vertical dust stratification, and (ii) with the
results of SPH bi-fluid hydrodynamic calculations.
  The parametric prescription and hydrodynamical calculations of stratification
both reproduce the observed brightness profiles well. These models also provide
a correct match for the observed star/ring integrated flux ratio. Another
solution with a well-mixed, but ``exotic'', dust size distribution also matches
the brightness profile ratios but fails to match the star/ring flux ratio.
These results give support to the presence of vertical stratification of the
dust in the ring of GG Tau and further predict the presence of a radial
stratification also.


title:
Droplets in the two-dimensional +-J spin glass: evidence for (non-)
  universality

abstract:
  Using mappings to computer-science problems and by applying sophisticated
algorithms, one can study numerically many problems much better compared to
applying standard approaches like Monte Carlo simulations. Here, using
calculations of ground states of suitable perturbed systems, droplets are
obtained in two-dimensional +-J spin glasses, which are in the focus of a
currently very lifely debate. Since a sophisticated matching algorithm is
applied here, exact ground states of large systems up to L^2=256^2 spins can be
generated. Furthermore, no equilibration or extrapolation to T=0 is necessary.
Three different +-J models are studied here: a) with open boundary conditions,
b) with fixed boundary conditions and c) a diluted system where a fraction
p=0.125 of all bonds is zero. For large systems, the droplet energy shows for
all three models a power-law behavior E_D L^\theta'_D with \theta'_D<0. This is
different from previous studies of domain walls, where a convergence to a
constant non-zero value (\theta_dw=0) has been found for such models. After
correcting for the non-compactness of the droplets, the results are likely to
be compatible with \theta_D= -0.29 for all three models.
  This is in accordance with the Gaussian system where \theta_D=-0.287(4)
(\nu=3.5 via \nu=-1/\theta_D). Nevertheless, the disorder-averaged spin-spin
correlation exponent \eta is determined here via the probability to have a
non-zero-energy droplet, and \eta~0.22$ is found for all three models, this
being in contrast to the behavior of the model with Gaussian interactions,
where exactly \eta=0.


title: Remarks to Glazek's results on n-ary groups

abstract:
  It is a survey of the results obtained by K. Glazek's and his co-workers. We
restrict our attention to the problems of axiomatizations of n-ary groups,
classes of n-ary groups, properties of skew elements and homomorphisms induced
by skew elements, constructions of covering groups, classifications and
representations of n-ary groups. Some new results are added too.


title:
The kinetics of inactivation of spheroidal microbial cells by pulsed
  electric fields

abstract:
  The nature of non-exponential kinetics in microbial cells inactivation by
pulsed electric fields (PEF) is discussed. It was demonstrated that possible
mechanism of non-exponential kinetics can be related to orientational disorder
in suspension of microbial cells of anisotropic form. A numerical studies of
spheroidal cell suspensions was carried out. The most pronounced deviations
from the exponential kinetics were observed for disordered suspensions of
prolate spheroids at small electric field strength $E$ or at large aspect ratio
$a$. For partially oriented suspensions, efficiency of inactivation enhances
with increasing of order parameter and field strength. A possibility of the
PEF-induced orientational ordering in microbial suspensions is discussed.


title: Quantum Gravity and Maximum Attainable Velocities in the Standard Model

abstract:
  A main difficulty in the quantization of the gravitational field is the lack
of experiments that discriminate among the theories proposed to quantize
gravity. Recently we showed that the Standard Model(SM) itself contains tiny
Lorentz invariance violation(LIV) terms coming from QG. All terms depend on one
arbitrary parameter $\alpha$ that set the scale of QG effects. In this talk we
review the LIV for mesons nucleons and leptons and apply it to study several
effects, including the GZK anomaly.


title: Modelling Thickness-Dependence of Ferroelectric Thin Film Properties

abstract:
  We present a segregrated strain model that describes the thickness-dependent
dielectric properties of ferroelectric films. Using a phenomenological Landau
approach, we present results for two specific materials, making comparison with
experiment and with first-principles calculations whenever possible. We also
suggest a "smoking gun" benchtop probe to test our elastic scenario.


title:
Local dark energy: HST evidence from the expansion flow around Cen A/M83
  galaxy group

abstract:
  A structure with a massive group in its center and a cool expansion outflow
outside is studied around the Cen A galaxy with the use of the Hubble Space
Telescope observations. It is demonstrated that the dynamics of the flow is
dominated by the antigravity of the dark energy background. The density of dark
energy in the cell is estimated to be near the global cosmological density.
This agrees with our previous result from the neighborhood of the Local group.
A notion of the ``Hubble cell'' is introduced as a building block of the local
structure of the universe.


title: Tangle and Brauer Diagram Algebras of Type Dn

abstract:
  A generalization of the Kauffman tangle algebra is given for Coxeter type Dn.
The tangles involve a pole or order 2. The algebra is shown to be isomorphic to
the Birman-Murakami-Wenzl algebra of the same type. This result extends the
isomorphism between the two algebras in the classical case, which in our
set-up, occurs when the Coxeter type is of type A with index n-1. The proof
involves a diagrammatic version of the Brauer algebra of type Dn in which the
Temperley-Lieb algebra of type Dn is a subalgebra.


title: Parabolic surfaces in hyperbolic space with constant curvature

abstract:
  We study parabolic linear Weingarten surfaces in hyperbolic space
$\rlopezh^3$. In particular, we classify two family of parabolic surfaces:
surfaces with constant Gaussian curvature and surfaces that satisfy the
relation $a\kappa_1+b\kappa_2=c$, where $\kappa_i$ are the principal
curvatures, and $a,b$ and $c$ are constant.


title:
The nature of a broad line radio galaxy: Simultaneous RXTE and Chandra
  HETG observations of 3C 382

abstract:
  We present the results from simultaneous chandra and rxte observations of the
X-ray bright Broad-Line Radio Galaxy (BLRG) 3C 382. The long (120 ks) exposure
with chandra HETG allows a detailed study of the soft X-ray continuum and of
the narrow component of the Fe Kalpha line. The rxte PCA data are used to put
an upper limit on the broad line component and constrain the hard X-ray
continuum. A strong soft excess below 1 keV is observed in the time-averaged
HETG spectrum, which can be parameterized with a steep power law or a thermal
model. The flux variability at low energies indicates that the origin of the
soft excess cannot be entirely ascribed to the circumnuclear diffuse emission,
detected by chandra on scales of 20-30 arcsec (22-33 kpc). A narrow (sigma<90
eV) Fe Kalpha line (with EW< 100 eV) is observed by the chandra HEG. Similar
values for the line parameters are measured by the rxte PCA, suggesting that
the contribution from a broad line component is negligible. The fact that the
exposure is split into two observations taken three days apart allows us to
investigate the spectral and temporal evolution of the source on different
timescales. Significant flux variability associated with spectral changes is
observed on timescales of hours and days. The spectral variability is similar
to that observed in radio-quiet AGN ruling out a jet-dominated origin of the
X-rays.


title: Polaron Physics in Optical Lattices

abstract:
  We investigate the effects of a nearly uniform Bose-Einstein condensate (BEC)
on the properties of immersed trapped impurity atoms. Using a weak-coupling
expansion in the BEC-impurity interaction strength, we derive a model
describing polarons, i.e., impurities dressed by a coherent state of Bogoliubov
phonons, and apply it to ultracold bosonic atoms in an optical lattice. We show
that, with increasing BEC temperature, the transport properties of the
impurities change from coherent to diffusive. Furthermore, stable polaron
clusters are formed via a phonon-mediated off-site attraction.


title: The Orientation of the Reconnection X-line

abstract:
  We propose a criterion for identifying the orientation of the X-line when two
regions of plasma with arbitrary densities, temperatures, and magnetic fields
undergo reconnection. The X-line points in the direction that maximizes the
(suitably-defined) Alfv\'en speed characterizing the reconnection outflow. For
many situations a good approximation is that the X-line bisects the angle
formed by the magnetic fields.


title:
Spectroscopic investigation of spin zero homonuclear and heteronuclear
  molecules

abstract:
  In the present article, we introduce a model to investigate the energy
spectrum of a relativistic rotor by considering the Klein-Gordon Hamiltonian.
Rotational spectral lines are a signature of homonuclear and heteronuclear
systems and play a key role in understanding diatomic molecules. We show that
the energy-correction term arising due to unequal masses influences the line
separation. Determining the rotational constant enables one to calculate the
moment of inertia and bond length of the molecule.


title: Theory of tunneling conductance of graphene NIS junctions

abstract:
  We calculate the tunneling conductance of a graphene normal
metal-insulator-superconductor (NIS) junction with a barrier of thickness $d$
and with an arbitrary voltage $V_0$ applied across the barrier region. We
demonstrate that the tunneling conductance of such a NIS junction is an
oscillatory function of both $d$ and $V_0$. We also show that the periodicity
and amplitude of such oscillations deviate from their universal values in the
thin barrier limit as obtained in earlier work [Phys. Rev. Lett. {\bf 97},
217001 (2006)] and become a function of the applied voltage $V_0$. Our results
reproduces the earlier results on tunneling conductance of such junctions in
the thin [Phys. Rev. Lett. {\bf 97}, 217001 (2006)] and zero [Phys. Rev. Lett.
{\bf 97}, 067007 (2006)] barrier limits as special limiting cases. We discuss
experimental relevance of our results.


title:
Self-Compensation of Conductionin Cd0.95Zn0.05Te:Cl Crystals in a Wide
  Range of Cd Vapor Pressures

abstract:
  The process of self-compensation in Cd0.95Zn0.05Te:Cl solid-solution crystals
has been studied by annealing single crystals under a controlled Cd vapor
pressure, with subsequent measurements of the Hall effect, photoluminescence,
carrier lifetime and mobility, and photocurrent memory in the annealed
crystals. By means of this annealing, conditions of thermal treatment that make
it possible to fabricate low-conductivity samples with a low carrier density,
10E7-10E11 cm-3, are denned. In these samples, a p -- n conduction inversion is
observed at a higher free-carrier density ((n, p) near 10E9 cm-3) and the
dependence of the electron density on the Cd vapor pressure exhibits a more
gentle slope than in the case of CdTe:Cl crystals.
  The obtained data are dis-cussed in terms of a self-compensation model in
which intrinsic point defects act as acceptors with deep levels. This level is
attributed to a Zn vacancy, which remains active at high Cd pressure.


title: Three Years of Mira Variable CCD Photometry: What Has Been Learned?

abstract:
  The subject of micro-variability among Mira stars has received increased
attention since DeLaverny et al. (1998) reported short-term brightness
variations in 15 percent of the 250 Mira or Long Period Variable stars surveyed
using the broadband 340 to 890 nm Hp filter on the HIPPARCOS satellite. The
abrupt variations reported ranged 0.2 to 1.1 magnitudes, on time-scales between
2 to 100 hours, with a preponderance found nearer Mira minimum light phases.
However, the HIPPARCOS sampling frequency was extremely sparse and required
confirmation because of potentially important atmospheric dynamics and
dust-formation physics that could be revealed. We report on Mira light curve
sub-structure based on new CCD V and R band data, augmenting the known light
curves of Hipparcos-selected long period variables [LPVs], and interpret same
in terms of [1] interior structure, [2] atmospheric structure change, and/or
[3] formation of circumstellar [CS] structure. We propose that the alleged
micro-variability among Miras is largely undersampled, transient overtone
pulsation structure in the light curves.


title: Equivariant Bundles and Isotropy Representations

abstract:
  We introduce a new construction, the isotropy groupoid, to organize the orbit
data for split $\Gamma$-spaces. We show that equivariant principal $G$-bundles
over split $\Gamma$-CW complexes $X$ can be effectively classified by means of
representations of their isotropy groupoids. For instance, if the quotient
complex $A=\Gamma\backslash X$ is a graph, with all edge stabilizers toral
subgroups of $\Gamma$, we obtain a purely combinatorial classification of
bundles with structural group $G$ a compact connected Lie group. If $G$ is
abelian, our approach gives combinatorial and geometric descriptions of some
results of Lashof-May-Segal and Goresky-Kottwitz-MacPherson.


title: A simple description of the states $0^+$ and $2^+$ in $^{168}Er$

abstract:
  A sixth-order quadrupole boson Hamiltonian is used to describe 26 states
$0^+$ and 67 states $2^+$ which have been recently identified in $^{168}Er$.
Two closed expressions are alternatively used for energy levels. One
corresponds to a semi-classical approach while the other one represents the
exact eigenvalue of the model Hamiltonian. The semi-classical expression
involves four parameters, while the exact eigenvalue is determined by five
parameters. In each of the two descriptions a least square fit procedure is
adopted.
  Both expressions provide a surprisingly good agreement with the experimental
data.


title: Entanglement of localized states

abstract:
  We derive exact expressions for the mean value of Meyer-Wallach entanglement
Q for localized random vectors drawn from various ensembles corresponding to
different physical situations. For vectors localized on a randomly chosen
subset of the basis, <Q> tends for large system sizes to a constant which
depends on the participation ratio, whereas for vectors localized on adjacent
basis states it goes to zero as a constant over the number of qubits.
Applications to many-body systems and Anderson localization are discussed.


title:
Comparison of Particle Production in Quark and Gluon Fragmentation at
  sqrt s ~ 10 GeV

abstract:
  Using data collected with the CLEO III detector at the Cornell Electron
Storage Ring, we study the inclusive production of baryons/antibaryons (p, /)
and mesons (phi and f_2(1270)) in gluon-fragmentation and quark-fragmentation
processes. We first corroborate previous per-event total particle yields in
Upsilon(1S)->ggg compared with nearby continuum (e+e- -> qqbar) indicating
greater (x2) per-event yields of baryons in 3-gluon fragmentation. We find
similar results when we extend that comparison to include the Upsilon(2S) and
Upsilon(3S) resonances. With higher statistics, we now also probe the momentum
dependence of these per-event particle yields. Next, we compare particle
production in the photon-tagged process Upsilon(1S)->gggamma with that in e+e-
-> qqbar events, to allow comparison of two-parton with three-parton
particle-specific fragmentation. For each particle, we determine the
`enhancement' ratio, defined as the ratio of particle yields per gluon
fragmentation event compared to quark fragmentation event. Thus defined, an
enhancement of 1.0 implies equal per-event production in both gluon and quark
fragmentation. In the photon-tagged analysis (U(1S)->gggamma compared to e+e-
-> qqbar+gamma), we find almost no enhancement for protons (1.2+/-0.1), but a
significant enhancement (1.9+/-0.3) for /\'s. Overall, per-event baryon
production in radiative two-gluon fragmentation is somewhat smaller than that
observed in three-gluon decays of the Upsilon(1S). Our results for baryon
production are inconsistent with the predictions of the JETSET (7.3)
fragmentation model.


title:
A Jet-like Outflow toward the High-Mass (Proto)stellar Object IRAS
  18566+0408

abstract:
  We performed interferometric observations of a high-mass protostellar
candidate IRAS 18566+0408 in the \nh3 (J,K)=(1,1), (2,2) and (3,3) inversion
transitions, the SiO J=2-1 and HCN J=1-0 lines, and the 43 and 87 GHz continuum
emission using the VLA and OVRO. The 87 GHz continuum emission reveals two
continuum peaks MM-1 and MM-2 along a molecular ridge. The dominant peak MM-1
coincides with a compact emission feature at 43 GHz, and arises mostly from the
dust emission. For dust emissivity index $\beta$ of 1.3, the masses in the dust
peaks amount to 70 \msun for MM-1, and 27 \msun for MM-2. Assuming internal
heating, the central luminosities of MM-1 and MM-2 are $6 \times 10^4$ and $8
\times 10^3$ \lsun, respectively.
  The SiO emission reveals a well collimated outflow emanating from MM-1. The
jet-like outflow is also detected in \nh3 at velocities similar to the SiO
emission. The outflow, with a mass of 27 \msun, causes significant heating in
the gas to temperatures of 70 K, much higher than the temperature of $\lsim 15$
K in the extended core. Compact ($< 3''$) and narrow line ($<1.5$ \kms-1) \nh3
(3,3) emission features are found associated with the outflow. They likely
arise from weak population inversion in \nh3 similar to the maser emission.
  Toward MM-1, there is a compact \nh3 structure with a linewidth that
increases from 5.5 \kms-1 FHWM measured at 3$''$ resolution to 8.7 \kms-1\
measured at 1$''$ resolution. This linewidth is much larger than the FWHM of
$<$ 2 \kms-1 in the entire core, and does not appear to originate from the
outflow. This large linewidth may arise from rotation/infall, or relative
motions of unresolved protostellar cores.


title: Heat Equations and the Weighted $\bar\partial$-Problem

abstract:
  The purpose of this article is to establish regularity and pointwise upper
bounds for the (relative) fundamental solution of the heat equation associated
to the weighted dbar-operator in $L^2(C^n)$ for a certain class of weights. The
weights depend on a parameter, and we find pointwise bounds for heat kernel, as
well as its derivatives in time, space, and the parameter. We also prove
cancellation conditions for the heat semigroup. We reduce the $n$-dimensional
case to the one-dimensional case, and the estimates in one-dimensional case are
achieved by Duhamel's principle and commutator properties of the operators. As
an application, we recover estimates of heat kernels on polynomial models in
$C^2$.


title: Towards a Background Independent Quantum Gravity in Eight Dimensions

abstract:
  We start a program of background independent quantum gravity in eight
dimensions. We begin by considering canonical gravity \textit{a la}
"Kaluza-Klein" in $D=d+1$ dimensions. We show that our canonical gravity
approach can be applied to the case of self-dual gravity in four dimensions.
Further, by using our previously proposed classical action of Ashtekar
self-dual gravity formalism in eight dimensions, we proceed to develop the
canonical approach in eight dimensions. Our construction considers different
SO(8) symmetry breakings. In particular, the breaking $SO(8)=S_{R}^{7}% \times
S_{L}^{7}\times G_{2}$ plays an important role in our discussion.


title: A remark on helical waveguides

abstract:
  Motivated by a proposal to create an optical helix-shaped waveguides for cold
atoms and molecules, we discuss local perturbations which can create bound
states in such a setting. This is known about a local slowdown of the twist; we
show that a similar effect can result from a local tube protrusion or a change
of the helix radius in correlation with its pitch angle.

categories: quant-ph cond-mat.mes-hall math-ph math.MP


title: Bialgebra cohomology, pointed Hopf algebras, and deformations

abstract:
  We give explicit formulas for maps in a long exact sequence connecting
bialgebra cohomology to Hochschild cohomology. We give a sufficient condition
for the connecting homomorphism to be surjective. We apply these results to
compute all bialgebra two-cocycles of certain Radford biproducts
(bosonizations). These two-cocycles are precisely those associated to the
finite dimensional pointed Hopf algebras in the recent classification of
Andruskiewitsch and Schneider, in an interpretation of these Hopf algebras as
graded bialgebra deformations of Radford biproducts.


title:
On Magnetic Interlayer Coupling and Proximity Effect in a
  La$_{0.67}$Ca$_{0.33}$MnO$_3$(10 nm)/YBa$_2$Cu$_3$O$_7$(10 nm) Superlattice

abstract:
  We present a study of interlayer coupling and proximity effects in a
La$_{0.66}$Ca$_{0.33}$MnO$_3$(10 nm)/YBa$_2$Cu$_3$O$_7$(10 nm) superlattice.
Using element-sensitive x-ray probes, the magnetic state of Mn can be probed
without seeing the strong diamagnetism of the superconductor, which makes this
approach ideal to study changes in the magnetic properties across the
superconducting transition. By a combined experiment using {\it in situ}
transport measurements during polarized soft x-ray measurements, we were able
to see no noticeable influence of the superconducting state on the magnetic
properties and no evidence for magnetic coupling across a 10 nm YBCO layer.


title: Measurement of Upper Limits for Upsilon --> gamma + R Decays

abstract:
  Motivated by concerns regarding possible two-body contributions to the
recently-measured inclusive Upsilon(nS)->gamma+X (n=1, 2, 3) direct photon
spectra, we report on a new study of exclusive radiative decays of these narrow
Upsilon(nS) resonances into two-body final states R+gamma, with R a narrow
resonant hadronic state decaying into four or more charged particles. Such
two-body processes are not explicitly addressed in the extant theoretical
frameworks used to calculate the inclusive direct photon spectra, and must also
be explicitly inserted into Monte Carlo simulations. Using data collected from
the CLEO III detector at the Cornell Electron Storage Ring, we present upper
limits of order 0.01 per cent for such bottomonium two-body decays as a
function of the R recoil mass.


title: Moriond QCD 2007 - Theory Summary

abstract:
  Developments reported at the 2007 Moriond Workshop on QCD and Hadronic
Interactions are reviewed and placed in a theoretical context.


title:
Results for a turbulent system with unbounded viscosities: weak
  formulations, existence of solutions, boundedness, smoothness'

abstract:
  We consider a circulation system arising in turbulence modelling in fluid
dynamics with unbounded eddy viscosities. Various notions of weak solutions are
considered and compared. We establish existence and regularity results. In
particular we study the boundedness of weak solutions. We also establish an
existence result for a classical solution


title:
Holonomy representations which are a diagonal direct sum of two faithful
  representations

abstract:
  We study holonomy representations admitting a pair of supplementary faithful
sub-representations. In particular the cases where the sub-representations are
isomorphic respectively dual to each other are treated. In each case we have a
closer look at the classification in small dimension.


title: Representations admitting two pairs of supplementary invariant spaces

abstract:
  We examine the lattice generated by two pairs of supplementary vector
subspaces of a finite-dimensional vector space by intersection and sum, with
the aim of applying the results to the study of representations admitting two
pairs of supplementary invariant spaces, or one pair and a reflexive form. We
show that such a representation is a direct sum of three canonical
sub-representations which we characterize. We then focus on holonomy
representations with the same property.


title: Random Access Broadcast: Stability and Throughput Analysis

abstract:
  A wireless network in which packets are broadcast to a group of receivers
through use of a random access protocol is considered in this work. The
relation to previous work on networks of interacting queues is discussed and
subsequently, the stability and throughput regions of the system are analyzed
and presented. A simple network of two source nodes and two destination nodes
is considered first. The broadcast service process is analyzed assuming a
channel that allows for packet capture and multipacket reception. In this small
network, the stability and throughput regions are observed to coincide. The
same problem for a network with N sources and M destinations is considered
next. The channel model is simplified in that multipacket reception is no
longer permitted. Bounds on the stability region are developed using the
concept of stability rank and the throughput region of the system is compared
to the bounds. Our results show that as the number of destination nodes
increases, the stability and throughput regions diminish. Additionally, a
previous conjecture that the stability and throughput regions coincide for a
network of arbitrarily many sources is supported for a broadcast scenario by
the results presented in this work.


title: The Complexity of Simple Stochastic Games

abstract:
  In this paper we survey the computational time complexity of assorted simple
stochastic game problems, and we give an overview of the best known algorithms
associated with each problem.