title:
Scaling and isospin effects in quasielastic lepton-nucleus scattering in
  the Relativistic Mean Field Approach

abstract:
  The role of isospin in quasielastic electron scattering and charge-changing
neutrino reactions is investigated in the relativistic impulse approximation.
We analyze proton and neutron scaling functions making use of various
theoretical descriptions for the final-state interactions, focusing on the
effects introduced by the presence of strong scalar and vector terms in the
relativistic mean field approach. An explanation for the differences observed
in the scaling functions evaluated from $(e,e')$ and $(\nu,\mu)$ reactions is
provided by invoking the differences in isoscalar and isovector contributions.


title: Fonction Z\^eta de Hurwitz p-adique et irrationalit\'e

abstract:
  The knowledge on irrationality of p-adic zeta values has recently progressed.
The irrationality of zeta_2(2), \zeta_2(3) and of a few other p-adic series of
Dirichlet was obtained by F. Calegari. F. Beukers gave a more elementary proof
of this result. In parallel, T. Rivoal has just obtained, in the complex case,
some Pade approximants of Lerch functions. It is this work which, transposed to
C_p, enables us to obtain results of irrationality and linear independence.


title:
The correlations between the spin frequencies and kHz QPOs of Neutron
  Stars in LMXBs

abstract:
  We studied the correlations between spin frequencies and kilohertz
quasi-periodic oscillations (kHz QPOs) in neutron star low mass X-ray binaries.
The updated data of kHz QPOs and spin frequencies are statistically analyzed.
We found that when two simultaneous kHz QPOs are present in the power spectrum,
the minimum frequency of upper kHz QPO is at least 1.3 times larger than the
spin frequency, i.e. \nu_{s}<\nu_{2min}/1.3. We also found that the average kHz
QPO peak separation in 6 Atoll sources anti-correlates with the spin frequency
in the form \lan\dn\ran = -(0.19\pm0.05)\ns+(389.40\pm21.67)Hz. If we shifted
this correlation in the direction of the peak separation by a factor of 1.5,
this correlation matches the data points of the two accretion powered
millisecond X-ray pulsars, SAX J1808.4-3658 and XTE J1807-294.


title:
Effective temperature and Gilbert damping of a current-driven localized
  spin

abstract:
  Starting from a model that consists of a semiclassical spin coupled to two
leads we present a microscopic derivation of the Langevin equation for the
direction of the spin. For slowly-changing direction it takes on the form of
the stochastic Landau-Lifschitz-Gilbert equation. We give expressions for the
Gilbert damping parameter and the strength of the fluctuations, including their
bias-voltage dependence. At nonzero bias-voltage the fluctuations and damping
are not related by the fluctuation-dissipation theorem. We find, however, that
in the low-frequency limit it is possible to introduce a voltage-dependent
effective temperature that characterizes the fluctuations in the direction of
the spin, and its transport-steady-state probability distribution function.


title: Adding Charges to N=4 Dyons

abstract:
  The spectrum of dyons in a class of N=4 supersymmetric string theories has
been found for a specific set of electric and magnetic charge vectors. We
extend the analysis to more general charge vectors by considering various
charge carrying collective excitations of the original system.


title: On b-function, spectrum and multiplier ideals

abstract:
  We give a survey on b-function, spectrum, and multiplier ideals together with
certain interesting relations among them including the case of arbitrary
subvarieties.


title: Asymptotic velocity of one dimensional diffusions with periodic drift

abstract:
  We consider the asymptotic behaviour of the solution of one dimensional
stochastic differential equations and Langevin equations in periodic
backgrounds with zero average. We prove that in several such models, there is
generically a non vanishing asymptotic velocity, despite of the fact that the
average of the background is zero.


title:
Holomorphic quadratic differentials and the Bernstein problem in
  Heisenberg space

abstract:
  We classify the entire minimal vertical graphs in the 3 dimensional
Heisenberg group Nil endowed with a Riemannian left-invariant metric. This
classification, which provides a solution to the Bernstein problem in Nil, is
given in terms of the Abresch-Rosenberg holomorphic differential for minimal
surfaces in Nil.


title:
Photo-z for weak lensing tomography from space: the role of optical and
  near-IR photometry

abstract:
  We study in detail the photometric redshift requirements needed for
tomographic weak gravitational lensing in order to measure accurately the Dark
Energy equation of state. In particular, we examine how ground-based photometry
(u,g,r,i,z,y) can be complemented by space-based near-infrared (IR) photometry
(J,H), e.g. on board the planned DUNE satellite. Using realistic photometric
redshift simulations and an artificial neural network photo-z method we
evaluate the Figure of Merit for the Dark Energy parameters $(w_0, w_a)$. We
consider a DUNE-like broad optical filter supplemented with ground-based
multi-band optical data from surveys like the Dark Energy Survey, Pan-STARRS
and LSST. We show that the Dark Energy Figure of Merit would improved by a
factor of 1.3 to 1.7 if IR filters are added on board DUNE. Furthermore we show
that with IR data catastrophic photo-z outliers can be removed effectively.
There is an interplay between the choice of filters, the magnitude limits and
the removal of outliers. We draw attention to the dependence of the results on
the galaxy formation scenarios encoded into the mock galaxies, e.g the galaxy
reddening. For example, deep u band data could be as effective as the IR. We
also find that about $10^5-10^6$ spectroscopic redshifts are needed for
calibration of the full survey.


title:
Study and optimization of ion-irradiated High-Tc Josephson nanoJunctions
  by Monte Carlo simulations

abstract:
  High Tc Josephson nanoJunctions (HTc JnJ) made by ion irradiation have
remarkable properties for technological applications. However, the spread in
their electrical characteristics increases with the ion dose. We present a
simple model to explain the JnJ inhomogeneities, which accounts quantitatively
for experimental data. The spread in the slit's width of the irradiation mask
is the limiting factor.Monte Carlo simulations have been performed using
different irradiation conditions to study their influence on the spread of the
JnJ charcateristics. A "universal" behavior has been evidenced, which allows to
propose new strategies to optimize JnJ reproducibility.


title:
A Spitzer Space Telescope Study of SN 2003gd: Still No Direct Evidence
  that Core-Collapse Supernovae are Major Dust Factories

abstract:
  We present a new, detailed analysis of late-time mid-infrared (IR)
observations of the Type II-P supernova (SN) 2003gd. At about 16 months after
the explosion, the mid-IR flux is consistent with emission from 4 x 10^(-5)
M(solar) of newly condensed dust in the ejecta. At 22 months emission from
point-like sources close to the SN position was detected at 8 microns and 24
microns. By 42 months the 24 micron flux had faded. Considerations of
luminosity and source size rule out the ejecta of SN 2003gd as the main origin
of the emission at 22 months. A possible alternative explanation for the
emission at this later epoch is an IR echo from pre-existing circumstellar or
interstellar dust. We conclude that, contrary to the claim of Sugerman et al.
(2006, Science, 313, 196), the mid-IR emission from SN 2003gd does not support
the presence of 0.02 M(solar) of newly formed dust in the ejecta. There is, as
yet, no direct evidence that core-collapse supernovae are major dust factories.


title: Contractible groups and linear dilatation structures

abstract:
  A dilatation structure on a metric space, arXiv:math/0608536v4, is a notion
in between a group and a differential structure, accounting for the approximate
self-similarity of the metric space.
  The basic objects of a dilatation structure are dilatations (or
contractions). The axioms of a dilatation structure set the rules of
interaction between different dilatations.
  Linearity is also a property which can be explained with the help of a
dilatation structure. In this paper we show that we can speak about two kinds
of linearity: the linearity of a function between two dilatation structures and
the linearity of the dilatation structure itself.
  Our main result here is a characterization of contractible groups in terms of
dilatation structures. To a normed conical group (normed contractible group) we
can naturally associate a linear dilatation structure. Conversely, any linear
and strong dilatation structure comes from the dilatation structure of a normed
contractible group.


title:
MAGMA: a 3D, Lagrangian magnetohydrodynamics code for merger
  applications

abstract:
  We present a new, completely Lagrangian magnetohydrodynamics code that is
based on the SPH method. The equations of self-gravitating hydrodynamics are
derived self-consistently from a Lagrangian and account for variable smoothing
length (``grad-h''-) terms in both the hydrodynamic and the gravitational
acceleration equations. The evolution of the magnetic field is formulated in
terms of so-called Euler potentials which are advected with the fluid and thus
guarantee the MHD flux-freezing condition. This formulation is equivalent to a
vector potential approach and therefore fulfills the
$\vec{\nabla}\cdot\vec{B}=0$-constraint by construction. Extensive tests in
one, two and three dimensions are presented. The tests demonstrate the
excellent conservation properties of the code and show the clear superiority of
the Euler potentials over earlier magnetic SPH formulations.


title: Does P=NP?

abstract:
  This paper has been withdrawn Abstract: This paper has been withdrawn by the
author due to the publication.


title: Embedding Degree of Hyperelliptic Curves with Complex Multiplication

abstract:
  Consider the Jacobian of a genus two curve defined over a finite field and
with complex multiplication. In this paper we show that if the l-Sylow subgroup
of the Jacobian is not cyclic, then the embedding degree of the Jacobian with
respect to l is one.


title: The dynamical status of the galaxy cluster Abell 115

abstract:
  We present the results of a new spectroscopic and photometric survey of the
hot, binary X-ray cluster A115 at z=0.193, containing a radio relic. We combine
galaxy velocity and position information to select 85 galaxies recognized as
cluster members (from 115 galaxies observed at TNG telescope), determine global
dynamical properties and detect substructures. We find that A115 presents
velocity dispersion of sigma_v=1362_{-108}^{+126} km/s. Our analysis confirms
the presence of two structures (A115N and A115S) of cluster--type well
recognizable in the plane of the sky and shows that they differ of ~2000 km/s
in the LOS velocity. We estimate that A115S is slightly dynamically more
important than A115N having sigma_v=900-1100 km/s vs sigma_v=750-850 km/s.
Moreover, we find evidence for two small groups at low velocities. We estimate
a global cluster virial mass of 2.2--3.5 e15 h_70 Msun. Our results agree with
a pre--merging scenario where A115N and A115S are colliding with a LOS impact
velocity Delta v~1600 km/s.The most likely solution to the two--body problem
suggests that the merging axis lies at $\sim 20$ degrees from the plane of the
sky and that the cores will cross after ~0.1 Gyr. The radio relic with its
largest dimension perpendicular to the merging axis is likely connected to this
merger.


title:
Multipolar Reactive DPD: A Novel Tool for Spatially Resolved Systems
  Biology

abstract:
  This article reports about a novel extension of dissipative particle dynamics
(DPD) that allows the study of the collective dynamics of complex chemical and
structural systems in a spatially resolved manner with a combinatorially
complex variety of different system constituents. We show that introducing
multipolar interactions between particles leads to extended membrane structures
emerging in a self-organized manner and exhibiting both the necessary
mechanical stability for transport and fluidity so as to provide a
two-dimensional self-organizing dynamic reaction environment for kinetic
studies in the context of cell biology. We further show that the emergent
dynamics of extended membrane bound objects is in accordance with scaling laws
imposed by physics.


title: The Quantum Query Complexity of Algebraic Properties

abstract:
  We present quantum query complexity bounds for testing algebraic properties.
For a set S and a binary operation on S, we consider the decision problem
whether $S$ is a semigroup or has an identity element. If S is a monoid, we
want to decide whether S is a group.
  We present quantum algorithms for these problems that improve the best known
classical complexity bounds. In particular, we give the first application of
the new quantum random walk technique by Magniez, Nayak, Roland, and Santha
that improves the previous bounds by Ambainis and Szegedy. We also present
several lower bounds for testing algebraic properties.


title: Wakes in a Collisional Quark-Gluon Plasma

abstract:
  Wakes created by a parton moving through a static and infinitely extended
quark-gluon plasma are considered. In contrast to former investigations
collisions within the quark-gluon plasma are taken into account using a
transport theoretical approach (Boltzmann equation) with a
Bhatnagar-Gross-Krook collision term. Within this model it is shown that the
wake structure changes significantly compared to the collisionless case.


title:
On convergence of the extended strong-property-fluctuation theory for
  bianisotropic homogenized composites

abstract:
  The strong-property-fluctuation theory (SPFT) provides a sophisticated means
of estimating the effective constitutive parameters of a homogenized composite
material (HCM), which takes account of the statistical distribution of the
component particles. We present an extended version of the third-order SPFT in
which the component particles are represented as depolarization regions of
nonzero volume. Numerical results are provided for a bianisotropic
homogenization scenario wherein the HCM is a Faraday chiral medium. Thereby,
convergence of the extended SPFT at the second-order level of approximation is
demonstrated within the long-wavelength regime.


title: Rational homotopy type of subspace arrangements with a geometric lattice

abstract:
  Let A be a subspace arrangement with a geometric lattice such that codim(x) >
1 for every x in A. Using rational homotopy theory, we prove that the
complement M(A) is rationally elliptic if and only if the sum of the orthogonal
subspaces is a direct sum. The homotopy type of M(A) is also given: it is a
product of odd dimensional spheres. Finally, some other equivalent conditions
are given, such as Poincare duality. Those results give a complete description
of arrangements (with geometric lattice and with the codimension condition on
the subspaces) such that M(A) is rationally elliptic, and show that most
arrangements have an hyperbolic complement.


title:
An Algorithm for Computing Cusp Points in the Joint Space of 3-RPR
  Parallel Manipulators

abstract:
  This paper presents an algorithm for detecting and computing the cusp points
in the joint space of 3-RPR planar parallel manipulators. In manipulator
kinematics, cusp points are special points, which appear on the singular curves
of the manipulators. The nonsingular change of assembly mode of 3-RPR parallel
manipulators was shown to be associated with the existence of cusp points. At
each of these points, three direct kinematic solutions coincide. In the
literature, a condition for the existence of three coincident direct kinematic
solutions was established, but has never been exploited, because the algebra
involved was too complicated to be solved. The algorithm presented in this
paper solves this equation and detects all the cusp points in the joint space
of these manipulators.


title:
Homotopy Lie algebra of the complements of subspace arrangements with
  geometric lattices

abstract:
  Let A be a geometric arrangement such that codim(x) > 1 for every x in A. We
prove that, if the complement space M(A) is rationally hyperbolic, then there
exists an injective from a free Lie algebra L(u,v) to the homotopy Lie algebra
of M(A).


title: Typer la d\'e-s\'erialisation sans s\'erialiser les types

abstract:
  In this paper, we propose a way of assigning static type information to
unmarshalling functions and we describe a verification technique for
unmarshalled data that preserves the execution safety provided by static type
checking. This technique, whose correctness is proven, relies on singleton
types whose values are transmitted to unmarshalling routines at runtime, and on
an efficient checking algorithm able to deal with sharing and cycles.


title: DWEB: A Data Warehouse Engineering Benchmark

abstract:
  Data warehouse architectural choices and optimization techniques are critical
to decision support query performance. To facilitate these choices, the
performance of the designed data warehouse must be assessed. This is usually
done with the help of benchmarks, which can either help system users comparing
the performances of different systems, or help system engineers testing the
effect of various design choices. While the TPC standard decision support
benchmarks address the first point, they are not tuneable enough to address the
second one and fail to model different data warehouse schemas. By contrast, our
Data Warehouse Engineering Benchmark (DWEB) allows to generate various ad-hoc
synthetic data warehouses and workloads. DWEB is fully parameterized to fulfill
data warehouse design needs. However, two levels of parameterization keep it
relatively easy to tune. Finally, DWEB is implemented as a Java free software
that can be interfaced with most existing relational database management
systems. A sample usage of DWEB is also provided in this paper.


title: DOEF: A Dynamic Object Evaluation Framework

abstract:
  In object-oriented or object-relational databases such as multimedia
databases or most XML databases, access patterns are not static, i.e.,
applications do not always access the same objects in the same order
repeatedly. However, this has been the way these databases and associated
optimisation techniques like clustering have been evaluated up to now. This
paper opens up research regarding this issue by proposing a dynamic object
evaluation framework (DOEF) that accomplishes access pattern change by defining
configurable styles of change. This preliminary prototype has been designed to
be open and fully extensible. To illustrate the capabilities of DOEF, we used
it to compare the performances of four state of the art dynamic clustering
algorithms. The results show that DOEF is indeed effective at determining the
adaptability of each dynamic clustering algorithm to changes in access pattern.


title: Decision tree modeling with relational views

abstract:
  Data mining is a useful decision support technique that can be used to
discover production rules in warehouses or corporate data. Data mining research
has made much effort to apply various mining algorithms efficiently on large
databases. However, a serious problem in their practical application is the
long processing time of such algorithms. Nowadays, one of the key challenges is
to integrate data mining methods within the framework of traditional database
systems. Indeed, such implementations can take advantage of the efficiency
provided by SQL engines. In this paper, we propose an integrating approach for
decision trees within a classical database system. In other words, we try to
discover knowledge from relational databases, in the form of production rules,
via a procedure embedding SQL queries. The obtained decision tree is defined by
successive, related relational views. Each view corresponds to a given
population in the underlying decision tree. We selected the classical Induction
Decision Tree (ID3) algorithm to build the decision tree. To prove that our
implementation of ID3 works properly, we successfully compared the output of
our procedure with the output of an existing and validated data mining
software, SIPINA. Furthermore, since our approach is tuneable, it can be
generalized to any other similar decision tree-based method.


title: Warehousing Web Data

abstract:
  In a data warehousing process, mastering the data preparation phase allows
substantial gains in terms of time and performance when performing
multidimensional analysis or using data mining algorithms. Furthermore, a data
warehouse can require external data. The web is a prevalent data source in this
context. In this paper, we propose a modeling process for integrating diverse
and heterogeneous (so-called multiform) data into a unified format.
Furthermore, the very schema definition provides first-rate metadata in our
data warehousing context. At the conceptual level, a complex object is
represented in UML. Our logical model is an XML schema that can be described
with a DTD or the XML-Schema language. Eventually, we have designed a Java
prototype that transforms our multiform input data into XML documents
representing our physical model. Then, the XML documents we obtain are mapped
into a relational database we view as an ODS (Operational Data Storage), whose
content will have to be re-modeled in a multidimensional way to allow its
storage in a star schema-based warehouse and, later, its analysis.


title: Web data modeling for integration in data warehouses

abstract:
  In a data warehousing process, the data preparation phase is crucial.
Mastering this phase allows substantial gains in terms of time and performance
when performing a multidimensional analysis or using data mining algorithms.
Furthermore, a data warehouse can require external data. The web is a prevalent
data source in this context, but the data broadcasted on this medium are very
heterogeneous. We propose in this paper a UML conceptual model for a complex
object representing a superclass of any useful data source (databases, plain
texts, HTML and XML documents, images, sounds, video clips...). The translation
into a logical model is achieved with XML, which helps integrating all these
diverse, heterogeneous data into a unified format, and whose schema definition
provides first-rate metadata in our data warehousing context. Moreover, we
benefit from XML's flexibility, extensibility and from the richness of the
semi-structured data model, but we are still able to later map XML documents
into a database if more structuring is needed.


title:
Mixing the Objective Caml and C# Programming Models in the .Net
  Framework

abstract:
  We present a new code generator, called O'Jacare.net, to inter-operate
between C# and Objective Caml through their object models. O'Jacare.net defines
a basic IDL (Interface Definition Language) that describes classes and
interfaces in order to communicate between Objective Caml and C#. O'Jacare.net
generates all needed wrapper classes and takes advantage of static type
checking in both worlds. Although the IDL intersects these two object models,
O'Jacare.net allows to combine features from both.


title:
The production of Tsallis entropy in the limit of weak chaos and a new
  indicator of chaoticity

abstract:
  We study the connection between the appearance of a `metastable' behavior of
weakly chaotic orbits, characterized by a constant rate of increase of the
Tsallis q-entropy (Tsallis 1988), and the solutions of the variational
equations of motion for the same orbits. We demonstrate that the variational
equations yield transient solutions, lasting for long time intervals, during
which the length of deviation vectors of nearby orbits grows in time almost as
a power-law. The associated power exponent can be simply related to the
entropic exponent for which the q-entropy exhibits a constant rate of increase.
This analysis leads to the definition of a new sensitive indicator
distinguishing regular from weakly chaotic orbits, that we call `Average Power
Law Exponent' (APLE). We compare the APLE with other established indicators of
the literature. In particular, we give examples of application of the APLE in
a) a thin separatrix layer of the standard map, b) the stickiness region around
an island of stability in the same map, and c) the web of resonances of a 4D
symplectic map. In all these cases we identify weakly chaotic orbits exhibiting
the `metastable' behavior associated with the Tsallis q-entropy.


title: Evolving inductive generalization via genetic self-assembly

abstract:
  We propose that genetic encoding of self-assembling components greatly
enhances the evolution of complex systems and provides an efficient platform
for inductive generalization, i.e. the inductive derivation of a solution to a
problem with a potentially infinite number of instances from a limited set of
test examples. We exemplify this in simulations by evolving scalable circuitry
for several problems. One of them, digital multiplication, has been intensively
studied in recent years, where hitherto the evolutionary design of only
specific small multipliers was achieved. The fact that this and other problems
can be solved in full generality employing self-assembly sheds light on the
evolutionary role of self-assembly in biology and is of relevance for the
design of complex systems in nano- and bionanotechnology.


title: A simple uniform approach to complexes arising from forests

abstract:
  In this paper we present a unifying approach to study the homotopy type of
several complexes arising from forests. We show that this method applies
uniformly to many complexes that have been extensively studied.


title:
Design of the photonic crystal demultiplexers for ultra-short optical
  pulses using the gap-maps analysis

abstract:
  In the work, the new method for the design of the wavelength division
multiplexer on the basis of 2D photonic crystal integrated circuit for the
ultra-short pulses channel separation is proposed and investigated. The method
is based on the analysis of full photonic bandgap maps that allows defining the
ultra-short pulse demultiplexer parameters selection. For the method
approbation, there was synthesized the device in which the wideband filters are
used for the channel separation. As it was expected, the device effectively
separates 50 fs pulse channels with 1.31 and 1.55 microns wavelengths. The
obtained spectral characteristics and pulse pattern responses validate the
efficiency of the proposed method and the applicability of such devices to the
integrated photonic information processing circuits.


title:
Charge renormalization for effective interactions of colloids at water
  interfaces

abstract:
  We analyze theoretically the electrostatic interaction of surface-charged
colloids at water interfaces with special attention to the experimentally
relevant case of large charge densities on the colloid-water interface. Whereas
linear theory predicts an effective dipole potential the strength of which is
proportional to the square of the product of charge density and screening
length, nonlinear charge renormalization effects change this dependence to a
weakly logarithmic one. These results appear to be particularly relevant for
structure formation at air-water interfaces with arbitrarily shaped colloids.


title: The Fine Structure of Solar Prominences

abstract:
  Solar prominences and filaments (prominences projected against the solar
disk) exhibit a large variety of fine structures which are well observed down
to the resolution limit of ground-based telescopes. We describe the
morphological aspects of these fine structures which basically depend on the
type of a prominence (quiescent or active-region). Then we review current
theoretical scenarios which are aimed at explaining the nature of these
structures. In particular we discuss in detail the relative roles of magnetic
pressure and gas pressure (i.e., the value of the plasma-beta), as well as the
dynamical aspects of the fine structures. Special attention is paid to recent
numerical simulations which include a complex magnetic topology, energy balance
(heating and cooling processes), as well as the multidimensional radiative
transfer. Finally, we also show how new ground-based and space observations can
reveal various physical aspects of the fine structures including their
prominence-corona transition regions in relation to the orientation of the
magnetic field.


title:
Entanglement Assisted Classical Capacity of a Class of Quantum Channels
  with Long-Term Memory

abstract:
  In this paper we evaluate the entanglement assisted classical capacity of a
class of quantum channels with long-term memory, which are convex combinations
of memoryless channels. The memory of such channels can be considered to be
given by a Markov chain which is aperiodic but not irreducible.


title:
Observation of extremely slow hole spin relaxation in self-assembled
  quantum dots

abstract:
  We report the measurement of extremely slow hole spin relaxation dynamics in
small ensembles of self-assembled InGaAs quantum dots. Individual spin
orientated holes are optically created in the lowest orbital state of each dot
and read out after a defined storage time using spin memory devices. The
resulting luminescence signal exhibits a pronounced polarization memory effect
that vanishes for long storage times. The hole spin relaxation dynamics are
measured as a function of external magnetic field and lattice temperature. We
show that hole spin relaxation can occur over remarkably long timescales in
strongly confined quantum dots (up to ~270 us), as predicted by recent theory.
Our findings are supported by calculations that reproduce both the observed
magnetic field and temperature dependencies. The results suggest that hole spin
relaxation in strongly confined quantum dots is due to spin orbit mediated
phonon scattering between Zeeman levels, in marked contrast to higher
dimensional nanostructures where it is limited by valence band mixing.


title: Many-spinon states and the secret significance of Young tableaux

abstract:
  We establish a one-to-one correspondence between the Young tableaux
classifying the total spin representations of N spins and the exact eigenstates
of the the Haldane-Shastry model for a chain with N sites classified by the
total spins and the fractionally spaced single-particle momenta of the spinons.


title: Knots in the Skyrme-Faddeev model

abstract:
  The Skyrme-Faddeev model is a modified sigma model in three-dimensional
space, which has string-like topological solitons classified by the
integer-valued Hopf charge. Numerical simulations are performed to compute
soliton solutions for Hopf charges up to sixteen, with initial conditions
provided by families of rational maps from the three-sphere into the complex
projective line. A large number of new solutions are presented, including a
variety of torus knots for a range of Hopf charges. Often these knots are only
local energy minima, with the global minimum being a linked solution, but for
some values of the Hopf charge they are good candidates for the global minimum
energy solution. The computed energies are in agreement with Ward's conjectured
energy bound.


title: Bispectrality of multivariable Racah-Wilson polynomials

abstract:
  We construct a commutative algebra A_x of difference operators in R^p,
depending on p+3 real parameters which is diagonalized by the multivariable
Racah polynomials R_p(n;x) considered by Tratnik [27]. It is shown that for
specific values of the variables x=(x_1,x_2,...,x_p) there is a hidden duality
between n and x. Analytic continuation allows us to construct another
commutative algebra A_n in the variables n=(n_1,n_2,...,n_p) which is also
diagonalized by R_p(n;x). Thus R_p(n;x) solve a multivariable discrete
bispectral problem in the sense of Duistermaat and Grunbaum [8]. Since a change
of the variables and the parameters in the Racah polynomials gives the
multivariable Wilson polynomials [26], this change of variables and parameters
in A_x and A_n leads to bispectral commutative algebras for the multivariable
Wilson polynomials.


title: A Random Loop Model for Long Polymers

abstract:
  While the structure of chromatin has been studied in great detail on length
scales below 30 nm, amazingly little is known about the higher-order folding
motifs of chromatin in interphase. Recent experiments give evidence that the
folding may depend locally on gene density and transcriptional activity and
show a leveling-off at long distances where approximately $<R^2> \sim O(1)$. We
propose a new model that can explain this leveling-off by the formation of
random loops. We derive an analytical expression for the mean square
displacement between two beads where the average is taken over the thermal
ensemble with a fixed but random loop configuration, while quenched averaging
over the ensemble of different loop configurations -- which turns out to be
equivalent to averaging over an ensemble of random matrices -- is performed
numerically. A detailed investigation of this model shows that loops on all
scales are necessary to fit experimental data.


title:
The dust distribution in edge-on galaxies. Radiative transfer fits of V
  and K'-band images

abstract:
  Aims: I have analyzed a sample of seven nearby edge-on galaxies observed in
the V and K'-band, in order to infer the properties of the dust distribution.
  Methods: A radiative transfer model, including scattering, have been used to
decompose each image into a stellar disk, a bulge, and a dust disk. The
parameters describing the distributions have been obtained through standard X^2
minimization techniques.
  Results: The dust disks fitted to the V-band images are consistent with
previous work in literature: the radial scalelength of dust is larger than that
for stars (h_d/h_s ~ 1.5); the dust disk has a smaller vertical scalelength
than the stellar (z_d/z_s ~ 1/3); the dust disk is almost transparent when seen
face-on (central, face-on, optical depth tau_0 =0.5-1.5). Faster radiative
transfer models which neglect scattering can produce equivalent fits, with
changes in the derived parameters within the accuracy of full fits including
scattering. In the K'-band, no trace is found of a second, massive, dust disk
which has been invoked to explain observations of dust emission in the
submillimeter. I discuss the model degeneracies and the effect of complex
structures on the fitted distributions. In particular, most bulges in the
sample show a box/peanuts morphology with large residuals; two
lower-inclination galaxies show a dust ring distribution, which could be the
cause for the large fitted dust scalelengths.


title:
Uniform Mixing of Antiferromagnetism and High-Tc Superconductivity in
  Electron-doped Layers in Four-layered Ba2Ca3Cu4O8F2 : A New Phenomenon in an
  Electron Underdoped RegimePhenomenon in an Electron Underdoped Regime

abstract:
  We report Cu- and F-NMR studies on a four-layered high-temperature
superconductor Ba2Ca3Cu4O8F2(0234F(2.0)) with apical fluorine (F-1), an undoped
55 K-superconductor with a nominal Cu2+ valence on average. We reveal that this
compound exhibits the antiferromagnetism (AFM) with a Neel temperature TN=100 K
despite being a Tc= 55 K-superconductor. Through a comparison with a related
tri-layered cuprate Ba2Ca2Cu3O6F2 (0223F(2.0)), it is demonstrated that
electrons are transferred from the inner plane (IP) to the outer plane (OP) in
0234F(2.0) and 0223F(2.0), confirming the self-doped high-temperature
superconductivity (HTSC) having electron and hole doping in a single compound.
Remarlably, uniform mixing of AFM and HTSC takes place in both the
electron-doped OPs and the hole-doped IPs in 0234F(2.0).


title:
A Circulating Hydrogen Ultra-High Purification System for the MuCap
  Experiment

abstract:
  The MuCap experiment is a high-precision measurement of the rate for the
basic electroweak process of muon capture, mu- + p -> n + nu . The experimental
approach is based on an active target consisting of a time projection chamber
(TPC) operating with pure hydrogen gas. The hydrogen has to be kept extremely
pure and at a stable pressure. A Circulating Hydrogen Ultrahigh Purification
System was designed at the Petersburg Nuclear Physics Institute (PNPI) to
continuously clean the hydrogen from impurities. The system is based on an
adsorption cryopump to stimulate the hydrogen flow and on a cold adsorbent for
the hydrogen cleaning. It was installed at the Paul Scherrer Institute (PSI) in
2004 and performed reliably during three experiment runs. During several months
long operating periods the system maintained the hydrogen purity in the
detector on the level of 20 ppb for moisture, which is the main contaminant,
and of better than 7 ppb and 5 ppb for nitrogen and oxygen, respectively. The
pressure inside the TPC was stabilized to within 0.024% of 10 bar at a hydrogen
flow rate of 3 standard liters per minute.


title: First passage times and distances along critical curves

abstract:
  We propose a model for anomalous transport in inhomogeneous environments,
such as fractured rocks, in which particles move only along pre-existing
self-similar curves (cracks). The stochastic Loewner equation is used to
efficiently generate such curves with tunable fractal dimension $d_f$. We
numerically compute the probability of first passage (in length or time) from
one point on the edge of the semi-infinite plane to any point on the
semi-circle of radius $R$. The scaled probability distributions have a variance
which increases with $d_f$, a non-monotonic skewness, and tails that decay
faster than a simple exponential. The latter is in sharp contrast to
predictions based on fractional dynamics and provides an experimental signature
for our model.


title: Statistical significance of rich-club phenomena in complex networks

abstract:
  We propose that the rich-club phenomena in complex networks should be defined
in the spirit of bootstrapping, in which a null model is adopted to assess the
statistical significance of the rich-club detected. Our method can be served as
a definition of rich-club phenomenon and is applied to analyzing three real
networks and three model networks. The results improve significantly compared
with previously reported results. We report a dilemma with an exceptional
example, showing that there does not exist an omnipotent definition for the
rich-club phenomenon.


title:
Logarithmic corrections and soft photon phenomenology in the multipole
  model of the nucleon form factors

abstract:
  We analyzed the presently available experimental data on nucleon
electromagnetic form factors within a multipole model based on dispersion
relations. A good fit of the data is achieved by considering the coefficients
of the multipole expansions as logarithmic functions of the momentum transfer
squared. The superconvergence relations, applied to this coefficients, makes
the model agree with unitary constraints and pQCD asymptotics for the Dirac and
Pauli form factors. The soft photon emission is proposed as a mechanism
responsible for the difference between the Rosenbluth, polarization and
beam--target--asymmetry data. It is shown, that the experimentally measured
cross sections depend not only on the Dirac and Pauli form factors, but also on
the average number of the photons emitted. For proton this number is shown to
be different for different types of experimental measurements and then
estimated phenomenologically. For neutron the same mechanism predicts, that the
data form different types of experiments must coincide with high accuracy. A
joint fit of all the experimental data reproduce the $Q^2-$dependence with the
accuracy $\chi^2/dof=0.86$. Predictions of the model, that 1) the ratios of the
proton form factors $G_E/G_M$ are different for Rosenbluth, polarization and
beam--target--asymmetry experiments and 2) similar ratios are nearly the same
for neutron, can be used for experimental verification of the model.


title:
Quantum entanglement, fair sampling, and reality: Is the moon there when
  nobody looks?

abstract:
  In 1981, David Mermin described a cleverly simplified version of Bell's
theorem. It pointed out in a straightforward way that interpreting entanglement
from a local realist point of view can be problematic. I propose here an
extended version of Mermin's device that can actually be given a simple local
realist interpretation through a sample selection bias, and I argue that we
still have no scientific reason to believe that the moon could possibly not be
there when nobody looks.


title: Grain Physics and Rosseland Mean Opacities

abstract:
  Tables of mean opacities are often used to compute the transfer of radiation
in a variety of astrophysical simulations from stellar evolution models to
proto-planetary disks. Often tables, such as Ferguson et al. (2005), are
computed with a predetermined set of physical assumptions that may or may not
be valid for a specific application. This paper explores the effects of several
assumptions of grain physics on the Rosseland mean opacity in an oxygen rich
environment. We find that changing the distribution of grain sizes, either the
power-law exponent or the shape of the distribution, has a marginal effect on
the total mean opacity. We also explore the difference in the mean opacity
between solid homogenous grains and grains that are porous or conglomorations
of several species. Changing the amount of grain opacity included in the mean
by assuming a grain-to-gas ratio significantly affects the mean opacity, but in
a predictable way.


title: Accumulation of chromium metastable atoms into an Optical Trap

abstract:
  We report the fast accumulation of a large number of metastable 52Cr atoms in
a mixed trap, formed by the superposition of a strongly confining optical trap
and a quadrupolar magnetic trap. The steady state is reached after about 400
ms, providing a cloud of more than one million metastable atoms at a
temperature of about 100 microK, with a peak density of 10^{18} atoms.m^{-3}.
We have optimized the loading procedure, and measured the light shift of the
5D4 state by analyzing how the trapped atoms respond to a parametric
excitation. We compare this result to a theoretical evaluation based on the
available spectroscopic data for chromium atoms.


title: Anomalous Diffusion of particles with inertia in external potentials

abstract:
  Recently a new type of Kramers-Fokker-Planck Equation has been proposed [R.
Friedrich et al. Phys. Rev. Lett. {\bf 96}, 230601 (2006)] describing anomalous
diffusion in external potentials. In the present paper the explicit cases of a
harmonic potential and a velocity-dependend damping are incorporated. Exact
relations for moments for these cases are presented and the asymptotic
behaviour for long times is discussed. Interestingly the bounding potential and
the additional damping by itself lead to a subdiffussive behaviour, while
acting together the particle becomes localized for long times.


title: Actin - Technical Report

abstract:
  The Boolean satisfiability problem (SAT) can be solved efficiently with
variants of the DPLL algorithm. For industrial SAT problems, DPLL with conflict
analysis dependent dynamic decision heuristics has proved to be particularly
efficient, e.g. in Chaff. In this work, algorithms that initialize the variable
activity values in the solver MiniSAT v1.14 by analyzing the CNF are evolved
using genetic programming (GP), with the goal to reduce the total number of
conflicts of the search and the solving time. The effect of using initial
activities other than zero is examined by initializing with random numbers. The
possibility of countering the detrimental effects of reordering the CNF with
improved initialization is investigated. The best result found (with validation
testing on further problems) was used in the solver Actin, which was submitted
to SAT-Race 2006.


title:
Estimates of the optimal density and kissing number of sphere packings
  in high dimensions

abstract:
  The problem of finding the asymptotic behavior of the maximal density of
sphere packings in high Euclidean dimensions is one of the most fascinating and
challenging problems in discrete geometry. One century ago, Minkowski obtained
a rigorous lower bound that is controlled asymptotically by $1/2^d$, where $d$
is the Euclidean space dimension. An indication of the difficulty of the
problem can be garnered from the fact that exponential improvement of
Minkowski's bound has proved to be elusive, even though existing upper bounds
suggest that such improvement should be possible. Using a
statistical-mechanical procedure to optimize the density associated with a
"test" pair correlation function and a conjecture concerning the existence of
disordered sphere packings [S. Torquato and F. H. Stillinger, Experimental
Math. {\bf 15}, 307 (2006)], the putative exponential improvement was found
with an asymptotic behavior controlled by $1/2^{(0.77865...)d}$. Using the same
methods, we investigate whether this exponential improvement can be further
improved by exploring other test pair correlation functions correponding to
disordered packings. We demonstrate that there are simpler test functions that
lead to the same asymptotic result. More importantly, we show that there is a
wide class of test functions that lead to precisely the same exponential
improvement and therefore the asymptotic form $1/2^{(0.77865...)d}$ is much
more general than previously surmised.


title:
Real versus complex beta-deformation of the N=4 planar super Yang-Mills
  theory

abstract:
  This is a sequel of our paper hep-th/0606125 in which we have studied the
{\cal N}=1 SU(N) SYM theory obtained as a marginal deformation of the {\cal
N}=4 theory, with a complex deformation parameter \beta and in the planar
limit. There we have addressed the issue of conformal invariance imposing the
theory to be finite and we have found that finiteness requires reality of the
deformation parameter \beta. In this paper we relax the finiteness request and
look for a theory that in the planar limit has vanishing beta functions. We
perform explicit calculations up to five loop order: we find that the
conditions of beta function vanishing can be achieved with a complex
deformation parameter, but the theory is not finite and the result depends on
the arbitrary choice of the subtraction procedure. Therefore, while the
finiteness condition leads to a scheme independent result, so that the
conformal invariant theory with a real deformation is physically well defined,
the condition of vanishing beta function leads to a result which is scheme
dependent and therefore of unclear significance. In order to show that these
findings are not an artefact of dimensional regularization, we confirm our
results within the differential renormalization approach.


title:
The First Law of Thermodynamics and the Thermodynamic Description of
  Elastic Solids

abstract:
  Historically, the thermodynamic behavior of gasses was described first and
the derived equations were adapted to solids. It is suggested that the current
thermodynamic description of solid phase is still incomplete because the
isothermal work done on or by the system is not counted in the internal energy.
It is also suggested that the isobaric work should not be deducted from the
internal energy because the system does not do work when it expands. Further
more it is suggested that Joule postulate regarding the mechanical equivalency
of heat -the first law of thermodynamics- is not universal and not applicable
to elastic solids. The equations for the proposed thermodynamic description of
solids are derived and tested by calculating the internal energies of the
system using the equation of state of MgO. The agreement with theory is good.


title: Busemann points of Artin groups of dihedral type

abstract:
  We study the horofunction boundary of an Artin group of dihedral type with
its word metric coming from either the usual Artin generators or the dual
generators. In both cases, we determine the horoboundary and say which points
are Busemann points, that is the limits of geodesic rays. In the case of the
dual generators, it turns out that all boundary points are Busemann points, but
this is not true for the Artin generators. We also characterise the geodesics
with respect to the dual generators, which allows us to calculate the
associated geodesic growth series.


title:
High order convergent multigrid methods on domains containing holes for
  black hole initial data

abstract:
  It is well known that multigrid methods are optimally efficient for solution
of elliptic equations (O(N)), which means that effort is proportional to the
number of points at which the solution is evaluated). Thus this is an ideal
method to solve the initial data/constraint equations in General Relativity for
(for instance) black hole interactions, or for other strong-field gravitational
configurations. Recent efforts have produced finite difference multigrid
solvers for domains with holes (excised regions). We present here the extension
of these concepts to higher order (fourth-, sixth- and eigth-order). The high
order convergence allows rapid solution on relatively small computational
grids. Also, general relativity evolution codes are moving to typically
fourth-order; data have to be computed at least as accurately as this same
order for straightfoward demonstration of the proper order of convergence in
the evolution.
  Our vertex-centered multigrid code demonstrates globally high-order-accurate
solutions of elliptic equations over domains containing holes, in two spatial
dimensions with fixed (Dirichlet) outer boundary conditions, and in three
spatial dimensions with {\it Robin} outer boundary conditions. We demonstrate a
``real world'' 3-dimensional problem which is the solution of the conformally
flat Hamiltonian constraint of General Relativity. The success of this method
depends on: a) the choice of the discretization near the holes; b) the
definition of the location of the inner boundary, which allows resolution of
the hole even on the coarsest grids; and on maintaining the same order of
convergence at the boundaries as in the interior of the computational domain.


title:
Nonorientable 3-manifolds admitting coloured triangulations with at most
  30 tetrahedra

abstract:
  We present the census of all non-orientable, closed, connected 3-manifolds
admitting a rigid crystallization with at most 30 vertices. In order to obtain
the above result, we generate, manipulate and compare, by suitable computer
procedures, all rigid non-bipartite crystallizations up to 30 vertices.


title: Generic equations for pattern formation in evolving interfaces

abstract:
  We present a general formalism which allows us to derive the evolution
equations describing one-dimensional (1D) and isotropic 2D interfacelike
systems, that is based on symmetries, conservation laws, multiple scale
arguments, and exploits the relevance of coarsening dynamics. Our approach
becomes especially significant in the presence of surface morphological
instabilities and allows us to classify the most relevant nonlinear terms in
the continuum description of these systems. The formalism applies to systems
ranging from eroded nanostructures to macroscopic pattern formation. In
particular, we show the validity of the theory for novel experiments on ion
plasma erosion.


title: Variations on leptogenesis

abstract:
  We study variations of the standard leptogenesis scenario that can arise if
an additional mass scale related to the breaking of some new symmetry (as for
example a flavor or the B-L symmetry) is present below the mass $M_{N_1}$ of
the lightest right-handed Majorana neutrino. Our scheme is inspired by U(1)
models of flavor \`a la Froggatt-Nielsen, and involves new vectorlike heavy
fields $F$. We show that depending on the specific hierarchy between $M_{N_1}$
and the mass scale of the fields $F$, qualitatively different realizations of
leptogenesis can emerge. We compute the CP asymmetries in $N_1$ decays in all
the relevant cases, and we conclude that in most situations leptogenesis could
be viable at scales much lower than in the standard scenario.


title:
A three-state prediction of single point mutations on protein stability
  changes

abstract:
  A basic question of protein structural studies is to which extent mutations
affect the stability. This question may be addressed starting from sequence
and/or from structure. In proteomics and genomics studies prediction of protein
stability free energy change (DDG) upon single point mutation may also help the
annotation process. The experimental SSG values are affected by uncertainty as
measured by standard deviations. Most of the DDG values are nearly zero (about
32% of the DDG data set ranges from -0.5 to 0.5 Kcal/mol) and both the value
and sign of DDG may be either positive or negative for the same mutation
blurring the relationship among mutations and expected DDG value. In order to
overcome this problem we describe a new predictor that discriminates between 3
mutation classes: destabilizing mutations (DDG<-0.5 Kcal/mol), stabilizing
mutations (DDG>0.5 Kcal/mol) and neutral mutations (-0.5<=DDG<=0.5 Kcal/mol).
In this paper a support vector machine starting from the protein sequence or
structure discriminates between stabilizing, destabilizing and neutral
mutations. We rank all the possible substitutions according to a three state
classification system and show that the overall accuracy of our predictor is as
high as 52% when performed starting from sequence information and 58% when the
protein structure is available, with a mean value correlation coefficient of
0.30 and 0.39, respectively. These values are about 20 points per cent higher
than those of a random predictor.


title: Why is Tin so soft?

abstract:
  The distribution of isoscalar monopole strength in the neutron-even
112-124Sn-isotopes has been computed using a relativistic
random-phase-approximation approach. The accurately-calibrated model used here
(``FSUGold'') has been successful in reproducing both ground-state observables
as well as collective excitations - including the giant monopole resonance
(GMR) in 90Zr, 144Sm, and 208Pb. Yet this same model significantly
overestimates the GMR energies in the Sn isotopes. It is argued that the
question of ``Why is Tin so soft?'' becomes an important challenge to the field
and one that should be answered without sacrificing the success already
achieved by several theoretical models.


title: Multiple Solutions for a Henon-Like Equation on the Annulus

abstract:
  For the equation (-\Delta u = | |x|-2 |^\alpha u^{p-1}), (1 < |x| < 3), we
prove the existence of two solutions for (\alpha) large, and of two additional
solutions when (p) is close to the critical Sobolev exponent (2^*=2N/(N-2)). A
symmetry--breaking phenomenon appears, showing that the least--energy solutions
cannot be radial functions.


title: Magnetically Induced Field Effect in Carbon Nanotube Devices

abstract:
  Three-terminal devices with conduction channels formed by quasi-metallic
carbon nanotubes (CNT) are shown to operate as nanotube-based field-effect
transistors under strong magnetic fields. The off-state conductance of the
devices varies exponentially with the magnetic flux intensity. We extract the
quasi-metallic CNT chirality as well as the characteristics of the Schottky
barriers formed at the metal-nanotube contacts from temperature-dependent
magnetoconductance measurements.


title:
Deep Spectroscopy of Systematically Surveyed Extended Lyman-alpha
  Sources at z~3-5

abstract:
  Spatially extended Ly-alpha sources that are faint and/or compact in coninuum
are candidates for extremely young (~< 10^7 yrs) galaxies at high redshifts. We
present medium-resolution (R~2000) spectroscopy of such extended Ly-alpha
sources found in our previous study at z~3-5, using VLT/VIMOS. The deep
spectroscopy showed that all 18 objects we observed have large equivalent
widths (EWs) exceeding 100 A. For about 30% of our sample (five objects), we
identified conspicuous asymmetry on the profiles of the Ly-alpha line. They
show broad wing emission components on the red side, and sharp cut-off on the
blue side of the Ly-alpha line. Such asymmetry is often seen in superwind
galaxies known to date, and also consistent with a theoretical prediction of
superwind activity. There are eight objects (8/18 ~ 40%) that have large EWs
exceeding 200 A, and no clear signature of superwind activities. Such large EWs
cannot be explained in terms of photo-ionization by a moderately old (>10^7
yrs) stellar population, even with a top-heavy IMF or an extremely low
metallicity. These eight objects clearly show a positive correlation between
the Ly-alpha luminosity and the velocity width. This suggests that these eight
objects are good candidates for forming-galaxies in a gas-cooling phase.


title:
Testing neutrino masses in little Higgs models via discovery of doubly
  charged Higgs at LHC

abstract:
  We have investigated the possibility of direct tests of little Higgs models
incorporating triplet Higgs neutrino mass mechanism at LHC experiments. We have
performed Monte Carlo studies of Drell-Yan pair production of doubly charged
Higgs boson \Phi^{++} followed by its leptonic decays which branching ratios
are fixed from the neutrino oscillation data. We propose appropriate selection
rules for the four-lepton signal, including reconstructed taus, which are
optimized for the discovery of \Phi^{++} with the lowest LHC luminosity. As the
Standard Model background can be effectively eliminated, an important aspect of
our study is the correct statistical treatment of the LHC discovery potential.
Adding detection efficiencies and measurement errors to the Monte Carlo
analyses, \Phi^{++} can be discovered up to the mass 250 GeV in the first year
of LHC, and 700 GeV mass is reachable for the integrated luminosity L=30
fb^{-1}.


title: The MSSM with heavy scalars

abstract:
  We perform a comprehensive analysis of the Minimal Supersymmetric Standard
Model (MSSM) in the scenario where the scalar partners of the fermions and the
Higgs particles (except for the Standard-Model-like one) are assumed to be very
heavy and are removed from the low-energy spectrum. We first summarize our
determination of the mass spectrum, in which we include the one-loop radiative
corrections and resum to all orders the leading logarithms of the large scalar
masses, and describe the implementation of these features in the FORTRAN code
SuSpect which calculates the masses and couplings of the MSSM particles. We
then study in detail the phenomenology of the model in scenarios where the
gaugino mass parameters are non-universal at the GUT scale, which leads to very
interesting features that are not present in the widely studied case of
universal gaugino mass parameters. We discuss the constraints from collider
searches and high-precision measurements, the cosmological constraints on the
relic abundance of the neutralino candidate for the Dark Matter in the Universe
- where new and interesting channels for neutralino annihilation appear - and
the gluino lifetime. We then analyze, in the case of non-universal gaugino
masses, the decays of the Higgs boson (in particular decays into and
contributions of SUSY particles), of charginos and neutralinos (in particular
decays into Higgs bosons and photons) and of gluinos, and highlight the
differences from the case of universal gaugino masses.


title: Trivialization of C(X)-algebras with strongly self-absorbing fibres

abstract:
  Suppose $A$ is a separable unital $C(X)$-algebra each fibre of which is
isomorphic to the same strongly self-absorbing and $K_{1}$-injective
$C^{*}$-algebra $D$. We show that $A$ and $C(X) \otimes D$ are isomorphic as
$C(X)$-algebras provided the compact Hausdorff space $X$ is finite-dimensional.
This statement is known not to extend to the infinite-dimensional case.


title:
ROXA: a new multi-frequency selected large sample of blazars with SDSS
  and 2dF optical spectroscopy

abstract:
  Context. Although Blazars are a small fraction of the overall AGN population
they are expected to be the dominant population of extragalactic sources in the
hard X-ray and gamma-ray bands and have been shown to be the largest
contaminant of CMB fluctuation maps. So far the number of known blazars is of
the order of several hundreds, but the forthcoming AGILE, GLAST and Planck
space observatories will detect several thousand of objects of this type. Aims.
In preparation for these missions it is necessary to identify new samples of
blazars to study their multi-frequency characteristics and statistical
properties. Methods. We compiled a sample of objects with blazar-like
properties via a cross-correlation between large radio (NVSS, ATCAPMN) and X-
ray surveys (RASS) using the SDSS-DR4 and 2dF survey data to spectroscopically
identify our candidates and test the validity of the selection method. Results.
We present the Radio - Optical - X-ray catalog built at ASDC (ROXA), a list of
816 objects among which 510 are confirmed blazars. Only 19% of the candidates
turned out to be certainly non-blazars demonstrating the high efficiency of our
selection method. Conclusions. Our catalog includes 173 new blazar
identifications, or about 10% of all presently known blazars. The relatively
high flux threshold in the X-ray energy band (given by the RASS survey)
preferentially selects objects with high fx / fr ratio leading to the discovery
of new High Energy Peaked BL Lac (HBLs). Our catalog therefore includes many
new potential targets for GeV-TeV observations.


title:
Top production at the Tevatron/LHC and nonstandard, strongly interacting
  spin one particles

abstract:
  In this note, we consider possible constraints from $t \bar t$ production on
the gauge bosons of theories with an extended strong interaction sector such as
axigluons or flavour universal colorons. Such constraints are found to be
competitive with those obtained from the dijet data. The current $t \bar t$
data from the Tevatron rule out axigluon masses ($m_A$) up to 900 GeV and 850
GeV at 2 $\sigma$ and 4 $\sigma$ levels respectively. For the case of flavour
universal colorons the data rule out a mass ($m_C$) below 800 GeV (780 GeV) at
the $2 (4) \sigma $ level and also the mass range between 900 GeV to 2.1 TeV at
2 $\sigma$ level, for $\cot \xi = 1$, where $\xi$ is the mixing angle. For
$\cot \xi =2$ on the other hand, the excluded range is $m_C \lsim 950 (920)$
GeV and $m_C \gsim 1.02 (1.15 \lsim m_C \lsim 1.8)$ TeV at $2 \sigma$ ($4
\sigma $) level. We point out that for higher axigluon/coloron masses, even for
the dijet channel, the limits on the coloron mass, for $\cot \xi = 1$, may be
different than those for the axigluon. We also compute the expected
forward-backward asymmetry for the case of the axigluons which would allow it
to be discriminated against the SM as also the colorons. We further find that
at the LHC, the signal should be visible in the $t \bar t$ invariant mass
spectrum for a wide range of axigluon and coloron masses that are still
allowed. We point out how top polarisation may be used to further discriminate
the axigluon and coloron case from the SM as well as from each other.


title: Composition of the Pseudoscalar Eta and Eta' Mesons

abstract:
  The composition of the eta and eta' mesons has long been a source of
discussion and is of current interest with new experimental results appearing.
We investigate what can be learnt from a number of different processes: V to P
gamma and P to V gamma (V and P are light vector and pseudoscalar mesons
respectively), P to gamma gamma, J/psi,psi' to P gamma, J/psi,psi' to P V, and
chi_{c0,2} to PP. These constrain the eta-eta' mixing angle to a consistent
value, phi approx 42 degrees; we find that the c cbar components are lesssim 5%
in amplitude. We also find that, while the data hint at a small gluonic
component in the eta', the conclusions depend sensitively on unknown form
factors associated with exclusive dynamics. In addition, we predict BR(psi' to
eta' gamma) approx 1 10^{-5} and BR(chi_{c0} to eta eta') approx 2 10^{-5} - 1
10^{-4}. We provide a method to test the mixing using chi_{c2} to eta eta, eta'
eta', and eta eta' modes and make some general observations on chi_{c0,2}
decays. We also survey the semileptonic and hadronic decays of bottom and
charmed mesons and find some modes where the mixing angle can be extracted
cleanly with the current experimental data, some where more data will allow
this, and some where a more detailed knowledge of the different amplitudes is
required.


title:
Model independent Breit-Wigner parameters of nucleon resonances
  S11(1535), S11(1650) and P11(1710)

abstract:
  Estimates of Breit-Wigner parameters of nucleon resonances were obtained by
phenomenological analysis of eta meson photoproduction on protons performed
completely by statistical procedures without appealing to theoretical models


title:
Three fermions in a box at the unitary limit: universality in a lattice
  model

abstract:
  We consider three fermions with two spin components interacting on a lattice
model with an infinite scattering length. Low lying eigenenergies in a cubic
box with periodic boundary conditions, and for a zero total momentum, are
calculated numerically for decreasing values of the lattice period. The results
are compared to the predictions of the zero range Bethe-Peierls model in
continuous space, where the interaction is replaced by contact conditions. The
numerical computation, combined with analytical arguments, shows the absence of
negative energy solution, and a rapid convergence of the lattice model towards
the Bethe-Peierls model for a vanishing lattice period. This establishes for
this system the universality of the zero interaction range limit.


title: Insensitivity of flavoured leptogenesis to low energy CP violation

abstract:
  If the baryon asymmetry of the Universe is produced by leptogenesis, CP
violation is required in the lepton sector. In the seesaw extension of the
Standard Model with three hierarchical right-handed neutrinos, we show that the
baryon asymmetry is insensitive to the PMNS phases: thermal leptogenesis can
work for any value of the observable phases. This result was well-known when
there are no flavour effects in leptogenesis; we show that it remains true when
flavour effects are included.


title: Soft gluons in Higgs plus two jet production

abstract:
  We investigate the effects of an all order QCD resummation of soft gluon
emissions for Higgs boson production in association with two hard jets. We
consider both the gluon-gluon fusion and weak boson fusion processes and show
how to resum a large part of the leading logarithms in the jet veto scale. Our
resummation improves on previous analyses which also aim to include the effects
of multiple soft gluon radiation. In addition we calculate the interference
between weak boson fusion and gluon-gluon fusion and find that it is small.


title: Theta+ width estimation with nonzero momentum transfer

abstract:
  We have used the light-cone formulation of Chiral-Quark Soliton Model to
estimate the width of the lightest pentaquark Theta+. We have found that the
effect of nonzero momentum transfer is important and reduces drastically the
width to about 0.43 MeV. This means that this effect is a piece of the small
width puzzle of exotic baryons.


title: Evanescent states in quantum wires with Rashba spin-orbit coupling

abstract:
  We discuss the calculation of evanescent states in quasi-one-dimensional
quantum wires in the presence of Rashba spin-orbit interaction. We suggest a
computational algorithm devised for cases in which longitudinal and transverse
motions are coupled. The dispersion relations are given for some selected
cases, illustrating the feasibility of the proposed computational method. As a
practical application, we discuss the solutions for a wire containing a
potential step.


title: Semi-Classical Quantum Fields Theories and Frobenius Manifolds

abstract:
  We show that a semi-classical quantum field theory comes with a versal family
with the property that the corresponding partition function generates all path
integrals and satisfies a system of 2nd order differential equations determined
by algebras of classical observables. This versal family gives rise to a notion
of special coordinates that is analogous to that in string theories. We also
show that for a large class of semi-classical theories, their moduli space has
the structure of a Frobenius super-manifold.


title: A SuperMassive Black Hole Fundamental Plane for Ellipticals

abstract:
  We obtain the coefficients of a new fundamental plane for supermassive black
holes at the centers of elliptical galaxies, involving measured central black
hole mass and photometric parameters which define the light distribution. The
galaxies are tightly distributed around this mass fundamental plane, with
improvement in the rms residual over those obtained from the $\mbh-\sigma$ and
$\mbh-L$ relations. This implies a strong multidimensional link between the
central massive black hole formation and global photometric properties of
elliptical galaxies and provides an improved estimate of black hole mass from
galaxy data.


title: Coriolis-Zeeman effect in rotating photonic crystal

abstract:
  Rotation-induced splitting of the otherwise degenerate photonic bands is
predicted for a two-dimensional photonic crystal made of evanescently coupled
microcavities. The symmetry-broken energy splitting is similar to the Zeeman
splitting of atomic levels or electron's (hole's) magnetic moment sublevels in
an external magnetic field. The orbital motion of photons in periodic photonic
lattice of microcavities is shown to enhance significantly such Coriolis-Zeeman
splitting as compared to a solitary microcavity [D.L. Boiko, Optics Express 2,
397 (1998)]. The equation of motion suggests that nonstationary rotation
induces quantum transitions between photonic states and, furthermore, that such
transitions will serve as a source of nonstationary gravitational field.


title: SLE in the three-state Potts model - a numerical study

abstract:
  The scaling limit of the spin cluster boundaries of the Ising model with
domain wall boundary conditions is SLE with kappa=3. We hypothesise that the
three-state Potts model with appropriate boundary conditions has spin cluster
boundaries which are also SLE in the scaling limit, but with kappa=10/3. To
test this, we generate samples using the Wolff algorithm and test them against
predictions of SLE: we examine the statistics of the Loewner driving function,
estimate the fractal dimension and test against Schramm's formula. The results
are in support of our hypothesis.


title: Stationary Dyonic Regular and Black Hole Solutions

abstract:
  We consider globally regular and black hole solutions in SU(2)
Einstein-Yang-Mills-Higgs theory, coupled to a dilaton field. The basic
solutions represent magnetic monopoles, monopole-antimonopole systems or black
holes with monopole or dipole hair. When the globally regular solutions carry
additionally electric charge, an angular momentum density results, except in
the simplest spherically symmetric case. We evaluate the global charges of the
solutions and their effective action, and analyze their dependence on the
gravitational coupling strength. We show, that in the presence of a dilaton
field, the black hole solutions satisfy a generalized Smarr type mass formula.


title: Comment on "note on the derivative of the hyperbolic cotangent"

abstract:
  In a couple of articles (Ford G W and O'Connell R F 1996 Nature 380 113 and
2002 J. Phys. A: Math. Gen. 35 4183) it was argued that the standard result for
the derivative of the hyperbolic cotangent in the literature, d \coth y/dy =
-{csch}^2 y is incomplete and the correct expression should have an additional
term proportional to the Dirac delta function. The purpose of this paper is to
demonstrate that this claim is incorrect.


title:
A spectrophotometric model applied to cluster galaxies: the WINGS
  dataset

abstract:
  [Abridged] The WIde-field Nearby Galaxy-cluster Survey (WINGS) is a project
aiming at the study of the galaxy populations in clusters in the local universe
(0.04<z<0.07) and the influence of environment on the physical properties of
galaxies. This survey provides a high quality set of spectroscopic data for
~6000 galaxies in 48 clusters. A salient feature of this model is the
possibility of treating dust extinction as a function of age, allowing younger
stars to be more obscured than older ones. Our technique, for the first time,
takes into account this feature in a spectral fitting code. A set of template
spectra spanning a wide range of star formation histories is built, with
features closely resembling those of typical spectra in our sample in terms of
spectral resolution, noise and wavelength coverage. Our method of analyzing
these spectra allows us to test the reliability and the uncertainties related
to each physical parameter we are inferring. The well-known degeneracy problem,
i.e. the non-uniqueness of the best fit solution (mass and extinction in
different age bins), can be addressed by assigning adequate error bars to the
recovered parameters. The values found in this way, together with their error
bars, identify the region of parameter space which contains all the possible
solutions for a given spectrum. A comparison test was also performed on a WINGS
subsample, containing objects in common with the Sloan Digital Sky Survey,
yielding excellent agreement. We find that the stellar content as a function of
age is reliably recovered in four main age bins and that the uncertainties only
mildly depend on the S/N ratio. The metallicity of the dominant stellar
population is not always recoverable unambiguosly, depending on the Star
Formation History pattern.


title:
Searching for Gravitational Radiation from Binary Black Hole MACHOs in
  the Galactic Halo

abstract:
  The Laser Interferometer Gravitational Wave Observatory (LIGO) is one of a
new generation of detectors of gravitational radiation. The existence of
gravitational radiation was first predicted by Einstein in 1916, however
gravitational waves have not yet been directly observed. One source of
gravitation radiation is binary inspiral. Two compact bodies orbiting each
other, such as a pair of black holes, lose energy to gravitational radiation.
As the system loses energy the bodies spiral towards each other. This causes
their orbital speed and the amount of gravitational radiation to increase,
producing a characteristic ``chirp'' waveform in the LIGO sensitive band. In
this thesis, matched filtering of LIGO science data is used to search for low
mass binary systems in the halo of dark matter surrounding the Milky Way.
Observations of gravitational microlensing events of stars in the Large
Magellanic Cloud suggest that some fraction of the dark matter in the halo may
be in the form of Massive Astrophysical Compact Halo Objects (MACHOs). It has
been proposed that low mass black holes formed in the early universe may be a
component of the MACHO population; some fraction of these black hole MACHOs
will be in binary systems and detectable by LIGO. The inspiral from a MACHO
binary composed of two 0.5 solar mass black holes enters the LIGO sensitive
band around 40 Hz. The chirp signal increases in amplitude and frequency,
sweeping through the sensitive band to 4400 Hz in 140 seconds. By using
evidence from microlensing events and theoretical predictions of the population
an upper limit is placed on the rate of black hole MACHO inspirals in the
galactic halo.


title:
Magnetization oscillations induced by a spin-polarized current in a
  point-contact geometry: mode hopping and non-linear damping effects

abstract:
  In this paper we study magnetization excitations induced in a thin extended
film by a spin-polarized dc-current injected through a point contact in the
current-perpendicular-to-plane (CPP) geometry. Using full-scale micromagnetic
simulations, we demonstrate that in addition to the oscillations of the
propagating wave type, there exist also two localized oscillation modes. The
first localized mode has a relatively homogeneous magnetization structure of
its kernel and corresponds to the so called 'bullet' predicted analytically by
Slavin and Tiberkevich (Phys. Rev. Lett., 95 (2005) 237201). Magnetization
pattern of the second localized mode kernel is highly inhomogeneous, leading to
a much smaller power of magnetoresistance oscillations caused by this mode. We
have also studied the influence of a non-linear damping for this system and
have found the following main qualitative effects: (i) the appearance of
frequency jumps within the existence region of the propagating wave mode and
(ii) the narrowing of the current region where the 'bullet' mode exists, until
this mode completely disappears for a sufficiently strong non-linear damping.


title:
Helical edge and surface states in HgTe quantum wells and bulk
  insulators

abstract:
  The quantum spin Hall (QSH) effect is the property of a new state of matter
which preserves time-reversal, has an energy gap in the bulk, but has
topologically robust gapless states at the edge. Recently, it has been shown
that HgTe quantum wells realize this novel effect. In this work, we start from
realistic tight-binding models and demonstrate the existence of the helical
edge states in HgTe quantum wells and calculate their physical properties. We
also show that 3d HgTe is a topological insulator under uniaxial strain, and
show that the surface states are described by single-component massless
relativistic Dirac fermions in 2+1 dimensions. Experimental predictions are
made based on the quantitative results obtained from realistic calculations.


title:
Weak first order transition in the three-dimensional site-diluted Ising
  antiferromagnet in a magnetic field

abstract:
  We perform intensive numerical simulations of the three-dimensional
site-diluted Ising antiferromagnet in a magnetic field at high values of the
external applied field. Even if data for small lattice sizes are compatible
with second-order criticality, the critical behavior of the system shows a
crossover from second-order to first-order behavior for large system sizes,
where signals of latent heat appear. We propose "apparent" critical exponents
for the dependence of some observables with the lattice size for a generic
(disordered) first-order phase transition.


title: Topological deformation of isolated horizons

abstract:
  We show that the Gauss-Bonnet term can have physical effects in four
dimensions. Specifically, the entropy of a black hole acquires a correction
that is proportional to the Euler characteristic of the cross sections of the
horizon. While this term is constant for a single black hole, it will be a
non-trivial function for a system with dynamical topologies such as black-hole
mergers: it is shown that for certain values of the GB parameter, the second
law of black-hole mechanics can be violated.


title: Small clones and the projection property

abstract:
  In 1986, the second author classified the minimal clones on a finite universe
into five types. We extend this classification to infinite universes and to
multiclones. We show that every non-trivial clone contains a "small" clone of
one of the five types. From it we deduce, in part, an earlier result, namely
that if $\mathcal C$ is a clone on a universe $A$ with at least two elements,
that contains all constant operations, then all binary idempotent operations
are projections and some $m$-ary idempotent operation is not a projection some
$m\geq 3$ if and only if there is a Boolean group $G$ on $A$ for which
$\mathcal C$ is the set of all operations $f(x_1,..., x_n)$ of the form
$a+\sum_{i\in I}x_i$ for $a\in A$ and $I\subseteq \{1,..., n\}$.


title: Deconstructing dwarf galaxies: a Suprime-Cam survey of Andromeda II

abstract:
  (Abridged) We present deep, sub-horizontal branch, multi-colour photometry of
the Andromeda II dwarf spheroidal (And II dSph) taken with Subaru Suprime-Cam.
We identify a red clump population in this galaxy, the first time this feature
has been detected in a M31 dSph, which are normally characterized as having no
significant intermediate age populations. We construct radial profiles for the
various stellar populations and show that the horizontal branch has a nearly
constant density spatial distribution out to large radius, whereas the reddest
red giant branch stars are centrally concentrated in an exponential profile. We
argue that these populations trace two distinct structural components in And II
and show that this assumption provides a good match to the overall radial
profile of this galaxy. The extended component dominates the stellar
populations at large radius, whereas the exponential component dominates the
inner few arcminutes. We show that the two components have very different
stellar populations; the exponential component has an average age of $\sim 7 -
10$ Gyrs old, is relatively metal-rich ([Fe/H] $\sim -1$) but with a
significant tail to low metallicities, and possesses a red clump. The extended
component, on the other hand, is ancient ($\sim 13$ Gyrs), metal-poor ([Fe/H]
$\sim -1.5$) with a narrower dispersion $\sigma_{\rm [Fe/H]} \simeq 0.28$, and
has a well developed blue horizontal branch. The extended component contains
approximately three-quarters of the light of And II and its unusual density
profile is unique in Local Group dwarf galaxies. This suggests that its
formation and/or evolution may have been quite different to other dwarf
galaxies.


title: A note on module-composed graphs

abstract:
  In this paper we consider module-composed graphs, i.e. graphs which can be
defined by a sequence of one-vertex insertions v_1,...,v_n, such that the
neighbourhood of vertex v_i, 2<= i<= n, forms a module (a homogeneous set) of
the graph defined by vertices v_1,..., v_{i-1}.
  We show that module-composed graphs are HHDS-free and thus homogeneously
orderable, weakly chordal, and perfect. Every bipartite distance hereditary
graph, every (co-2C_4,P_4)-free graph and thus every trivially perfect graph is
module-composed. We give an O(|V_G|(|V_G|+|E_G|)) time algorithm to decide
whether a given graph G is module-composed and construct a corresponding
module-sequence.
  For the case of bipartite graphs, module-composed graphs are exactly distance
hereditary graphs, which implies simple linear time algorithms for their
recognition and construction of a corresponding module-sequence.


title:
Differentiable and deformation type of algebraic surfaces, real and
  symplectic structures

abstract:
  Lecture 1: Projective and K\"ahler Manifolds, the Enriques classification,
construction techniques. Lecture 2: Surfaces of general type and their
Canonical models. Deformation equivalence and singularities. Lecture 3:
Deformation and diffeomorphism, canonical symplectic structure for surfaces of
general type. Lecture 4: Irrational pencils, orbifold fundamental groups, and
surfaces isogenous to a product. Lecture 5: Lefschetz pencils, braid and
mapping class groups, and diffeomorphism of ABC-surfaces. Epilogue:
Deformation, diffeomorphism and symplectomorphism type of surfaces of general
type.


title: Statistical mechanics and stability of a model eco-system

abstract:
  We study a model ecosystem by means of dynamical techniques from disordered
systems theory. The model describes a set of species subject to competitive
interactions through a background of resources, which they feed upon.
Additionally direct competitive or co-operative interaction between species may
occur through a random coupling matrix. We compute the order parameters of the
system in a fixed point regime, and identify the onset of instability and
compute the phase diagram. We focus on the effects of variability of resources,
direct interaction between species, co-operation pressure and dilution on the
stability and the diversity of the ecosystem. It is shown that resources can be
exploited optimally only in absence of co-operation pressure or direct
interaction between species.


title: Studies of Cosmic Rays with GeV Gamma Rays

abstract:
  We describe the role of GeV gamma-ray observations with GLAST-LAT (Gamma-ray
Large Area Space Telescope - Large Area Telescope) in identifying interaction
sites of cosmic-ray proton (or hadrons) with interstellar medium (ISM). We
expect to detect gamma rays from neutral pion decays in high-density ISM
regions in the Galaxy, Large Magellanic Cloud, and other satellite galaxies.
These gamma-ray sources have been detected already with EGRET (Energetic Gamma
Ray Experiment Telescope) as extended sources (eg. LMC and Orion clouds) and
GLAST-LAT will detect many more with a higher spatial resolution and in a wider
spectral range. We have developed a novel image restoration technique based on
the Richardson-Lucy algorithm optimized for GLAST-LAT observation of extended
sources. Our algorithm calculates PSF (point spread function) for each event.
This step is very important for GLAST-LAT and EGRET image analysis since PSF
varies more than one order of magnitude from one gamma ray to another depending
on its energy as well as its impact point and angle in the instrument. The
GLAST-LAT and EGRET image analysis has to cope with Poisson fluctuation due to
low number of detected photons for most sources. Our technique incorporates
wavelet filtering to minimize effects due to the fluctuation. Preliminary
studies on some EGRET sources are presented, which shows potential of this
novel image restoration technique for the identification and characterisation
of extended gamma-ray sources.


title:
Transverse Beam Spin Asymmetries in Forward-Angle Elastic
  Electron-Proton Scattering

abstract:
  We have measured the beam-normal single-spin asymmetry in elastic scattering
of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 =
0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely
using the elastic nucleon intermediate state, and generally agree with
calculations with significant inelastic hadronic intermediate state
contributions. A_n provides a direct probe of the imaginary component of the
2-gamma exchange amplitude, the complete description of which is important in
the interpretation of data from precision electron-scattering experiments.


title:
A new model for the structure of the DACs and SACs regions in the Oe and
  Be stellar atmospheres

abstract:
  In this paper we present a new mathematical model for the density regions
where a specific spectral line and its SACs/DACs are created in the Oe and Be
stellar atmospheres. In the calculations of final spectral line function we
consider that the main reasons of the line broadening are the rotation of the
density regions creating the spectral line and its DACs/SACs, as well as the
random motions of the ions. This line function is able to reproduce the
spectral feature and it enables us to calculate some important physical
parameters, such as the rotational, the radial and the random velocities, the
Full Width at Half Maximum, the Gaussian deviation, the optical depth, the
column density and the absorbed or emitted energy. Additionally, we can
calculate the percentage of the contribution of the rotational velocity and the
ions' random motions of the DACs/SACs regions to the line broadening. Finally,
we present two tests and three short applications of the proposed model.


title:
Influence of oxygen partial pressure on structural, transport and
  magnetic properties of Co doped TiO2 films

abstract:
  Thin films of Co-TiO2 are deposited on silicon and quartz substrates using
Pulse Laser Deposition (PLD) process at various oxygen partial pressures
ranging from 6.6 x 10-3 Pascals (Pa) to 53 Pa. Crystal structure, transport and
magnetic properties of reduced CoxTi(1-x)O2 (0 <x< 0.03) thin films are
investigated and are found to have a strong dependence on the oxygen partial
pressure. X-ray diffraction (XRD) data reveals the presence of mixed phase
material containing both anatase and rutile. However, these phases
intertransform with the change in the oxygen partial pressure in the chamber
during the growth of the films. X-ray Photoelectron Spectroscopy (XPS) shows no
Co or CoO related peaks for samples with Co concentration up to x=0.03.
However, the oxygen 1s peaks are asymmetric suggesting the presence of oxygen
vacancies. The transport and magnetic measurements show a clear dependence on
the concentration of oxygen vacancies. There is an enhancement in the
electrical conductivity and the magnetization as more vacancies are created in
the material. The resistivity as a function of temperature rho(T) follows the
polaronic behavior and the activation energies obtained, ~100 to 150meV, are
within the range that is typical for semiconducting materials.


title:
An Abelian two-Higgs model of strongly correlated electrons: phase
  structure, strengthening of phase transition and QCD at finite density

abstract:
  We investigate non-perturbative features of a three-dimensional Abelian Higgs
model with singly- and doubly-charged scalar fields coupled to a single compact
Abelian gauge field. The model is pretending to describe various planar systems
of strongly correlated electrons such as high-Tc superconductivity in the
overdoped regime and exotic materials possessing excitations with
fractionalized quantum numbers. The complicated phase structure of the model is
studied thoroughly using numerical tools and analytical arguments. In the
three-dimensional space of coupling parameters we identify the Fermi liquid,
the spin gap, the superconductor and the strange metallic phases. The behavior
of three kinds of topological defects -- holon and spinon vortices and
monopoles - is explored in various phases. We also observe a new effect, the
strong enhancement of the phase transition strength reflected in a lower order
of the transition: at sufficiently strong gauge coupling the two second order
phase transitions -- corresponding to spinon-pair and holon condensation lines
- join partially in the phase diagram and become a first order phase transition
in that region. The last observation may have an analogue in Quantum
Chromodynamics at non-zero temperature and finite baryon density. We argue that
at sufficiently large baryon density the finite-temperature transition between
the (3-flavor paired) color superconducting phase and the quark-gluon plasma
phases should be much stronger compared with the transition between 2-flavor
paired and 3-flavor paired superconducting phases.

categories: cond-mat.str-el cond-mat.supr-con hep-lat hep-ph


title: On a Holographic Model for Confinement/Deconfinement

abstract:
  We study the thermodynamics of the hard wall model, which consists in the
introduction of an infrared cut-off in asymptotically AdS spaces. This is a toy
model for confining backgrounds in the context of the gauge/gravity
correspondence. We use holographic renormalization and reproduce the existence
of a Hawking Page phase transition recently discussed by Herzog. We also show
that the entropy jumps from $N^0$ to $N^2$, which reinforces the interpretation
of this transition as the gravity dual of confinement/deconfinement. We also
show that similar results hold for the phenomenologically motivated soft wall
model, underlining the potential universality of our analysis.


title:
Effect of inelastic collisions on multiphonon Raman scattering in
  graphene

abstract:
  We calculate the probabilities of two- and four-phonon Raman scattering in
graphene and show how the relative intensities of the overtone peaks encode
information about relative rates of different inelastic processes electrons are
subject to. If the most important processes are electron-phonon and
electron-electron scattering, the rate of the latter can be deduced from the
Raman spectra.


title: Semiclassical thermodynamics of scalar fields

abstract:
  We present a systematic semiclassical procedure to compute the partition
function for scalar field theories at finite temperature. The central objects
in our scheme are the solutions of the classical equations of motion in
imaginary time, with spatially independent boundary conditions. Field
fluctuations -- both field deviations around these classical solutions, and
fluctuations of the boundary value of the fields -- are resummed in a Gaussian
approximation. In our final expression for the partition function, this
resummation is reduced to solving certain ordinary differential equations.
Moreover, we show that it is renormalizable with the usual 1-loop counterterms.


title:
On the distance between separatrices for the discretized logistic
  differential equation

abstract:
  We consider the discretization
  y(t+\epsilon)=y(t-\epsilon)+2\epsilon\big(1-y(t)^{2}\big),
  $\epsilon>0$ a small parameter, of the logistic differential equation
$y'=2\big(1-y^{2}\big)$, which can also be seen as a discretization of the
system
  {y'=2\big(1-v^{2}\big),
  v'= 2\big(1-y^{2}\big).
  This system has two saddle points at $A=(1,1)$, $B=(-1, -1)$ and there exist
stable and unstable manifolds. We will show that the stable manifold
$W_{s}^{+}$ of the point $A=(1,1)$ and the unstable manifold $W_{i}^{-}$ of the
point $B=(-1, -1)$ for the discretization do not coincide. The vertical
distance between these two manifolds is exponentially small but not zero, in
particular we give an asymptotic estimate of this distance. For this purpose we
will use a method adapted from the paper of Sch\"afke-Volkmer \cite{SV} using
formal series and accurate estimates of the coefficients.


title: Neutronic performances of the MEGAPIE target

abstract:
  The MEGAPIE project is a key experiment on the road to Accelerator Driven
Systems and it provides the scientific community with unique data on the
behavior of a liquid lead-bismuth spallation target under realistic and long
term irradiation conditions. The neutronic of such target is of course of prime
importance when considering its final destination as an intense neutron source.
This is the motivation to characterize the inside neutron flux of the target in
operation. A complex detector, made of 8 micro fission-chambers, has been built
and installed in the core of the target, few tens of centimeters from the
proton/Pb-Bi interaction zone. This detector is designed to measure the
absolute neutron flux inside the target, to give its spatial distribution and
to correlate its temporal variations with the beam intensity. Moreover,
integral information on the neutron energy distribution as a function of the
position along the beam axis could be extracted, giving integral constraints on
the neutron production models implemented in transport codes such as MCNPX.


title:
The redshift-dependence of gamma-ray absorption in the environments of
  strong-line AGN

abstract:
  The case of gamma-ray absorption due to photon-photon pair production of jet
photons in the external photon environment like accretion disk and broad-line
region radiation field of gamma-ray loud active galactic nuclei (AGN) that
exhibit strong emission lines is considered. I demonstrate that this ''local
opacity'', if detected, will almost unavoidably be redshift-dependent in the
sub-TeV range. This introduces non-negligible biases, and complicates
approaches for studying the evolution of the extragalactic background light
with contemporary GeV instruments like e.g. the Gamma-ray Large Area Space
Telescope (GLAST), etc., where the gamma-ray horizon is probed by means of
statistical analysis of absorption features (e.g. Fazio-Stecker relation, etc.)
in AGN spectra at various redshifts. It particularly applies to strong-line
quasars where external photon fields are potentially involved in gamma-ray
production.


title:
Visual Data Mining of Genomic Databases by Immersive Graph-Based
  Exploration

abstract:
  Biologists are leading current research on genome characterization
(sequencing, alignment, transcription), providing a huge quantity of raw data
about many genome organisms. Extracting knowledge from this raw data is an
important process for biologists, using usually data mining approaches.
However, it is difficult to deals with these genomic information using actual
bioinformatics data mining tools, because data are heterogeneous, huge in
quantity and geographically distributed. In this paper, we present a new
approach between data mining and virtual reality visualization, called visual
data mining. Indeed Virtual Reality becomes ripe, with efficient display
devices and intuitive interaction in an immersive context. Moreover, biologists
use to work with 3D representation of their molecules, but in a desktop
context. We present a software solution, Genome3DExplorer, which addresses the
problem of genomic data visualization, of scene management and interaction.
This solution is based on a well-adapted graphical and interaction paradigm,
where local and global topological characteristics of data are easily visible,
on the contrary to traditional genomic database browsers, always focused on the
zoom and details level.


title:
Refractometer for Tracking Changes in the Refractive Index of Air Near
  780 nm

abstract:
  A new system, consisting of a double channel Fabry Perot etalon and laser
diodes emitting around 780 nm is described and proposed to be used for air
refractive index measurements. The principle of this refractometer is based on
frequency measurements between optical laser sources. It permits
quasi-instantaneous measurement with a resolution better than and uncertainty
in the range. Some preliminary results on the stability of this system and the
measurements of the refractive index of air with this apparatus are presented.
The first measurements of the index of air at 780 nm are, within an
experimental uncertainty of the order of, in agreement with the predicted
values by the so-called revised Edl\'en equations. This result is to the best
of our knowledge the first to extend to the near infra-red the validity of the
revised Edl\'en equation derived for the wavelength range 350- 650 nm.


title: Supermassive Black Holes

abstract:
  Supermassive black holes have generally been recognized as the most
destructive force in nature. But in recent years, they have undergone a
dramatic shift in paradigm. These objects may have been critical to the
formation of structure in the early universe, spawning bursts of star formation
and nucleating proto-galactic condensations. Possibly half of all the radiation
produced after the Big Bang may be attributed to them, whose number is now
known to exceed 300 million. The most accessible among them is situated at the
Center of Our Galaxy. In the following pages, we will examine the evidence that
has brought us to this point, and we will understand why many expect to
actually image the event horizon of the Galaxy's central black hole within this
decade.