title:
Statistical Arbitrage and Optimal Trading with Transaction Costs in
  Futures Markets

abstract:
  We consider the Brownian market model and the problem of expected utility
maximization of terminal wealth. We, specifically, examine the problem of
maximizing the utility of terminal wealth under the presence of transaction
costs of a fund/agent investing in futures markets. We offer some preliminary
remarks about statistical arbitrage strategies and we set the framework for
futures markets, and introduce concepts such as margin, gearing and slippage.
The setting is of discrete time, and the price evolution of the futures prices
is modelled as discrete random sequence involving Ito's sums. We assume the
drift and the Brownian motion driving the return process are non-observable and
the transaction costs are represented by the bid-ask spread. We provide
explicit solution to the optimal portfolio process, and we offer an example
using logarithmic utility.


title: Nuclear Shadowing and Antishadowing in a Unitarized BFKL Equation

abstract:
  The nuclear shadowing and antishadowing effects are explained by a unitarized
BFKL equation. The $Q^2$- and $x$-variations of the nuclear parton
distributions are detailed based on the level of the unintegrated gluon
distribution. In particular, the asymptotical behavior of the unintegrated
gluon distribution near the saturation limit in nuclear targets is studied. Our
results in the nuclear targets are insensitive to the input distributions if
the parameters are fixed by the data of a free proton.


title:
Quantum Oscillations of Tunnel Magnetoresistance Induced by Spin-Wave
  Excitations in Ferromagnet-Ferromagnet-Ferromagnet Double Barrier Tunnel
  Junctions

abstract:
  The possibility of quantum oscillations of the tunnel conductance and
magnetoresistance induced by spin-wave excitations in a
ferromagnet-ferromagnet-ferromagnet double barrier tunnel junction, when the
magnetizations of the two side ferromagnets are aligned antiparallel to that of
the middle ferromagnet, is investigated in a self-consistent manner by means of
Keldysh nonequilibrium Green function method. It has been found that owing to
the s-d exchange interactions between conduction electrons and the spin density
induced by spin accumulation in the middle ferromagnet, the differential
conductance and the TMR indeed oscillate with the increase of bias voltage,
being consistent with the phenomenon that is observed recently in experiments.
The effects of magnon modes, the energy levels of electrons as well as the
molecular field in the central ferromagnet on the oscillatory transport
property of the system are also discussed.


title: Multi-layer atom chips for versatile atom micro manipulation

abstract:
  We employ a combination of optical UV- and electron-beam-lithography to
create an atom chip combining sub-micron wire structures with larger
conventional wires on a single substrate. The new multi-layer fabrication
enables crossed wire configurations, greatly enhancing the flexibility in
designing potentials for ultra cold quantum gases and Bose-Einstein
condensates. Large current densities of >6 x 10^7 A/cm^2 and high voltages of
up to 65 V across 0.3 micron gaps are supported by even the smallest wire
structures. We experimentally demonstrate the flexibility of the next
generation atom chip by producing Bose-Einstein condensates in magnetic traps
created by a combination of wires involving all different fabrication methods
and structure sizes.


title:
On the condensed density of the generalized eigenvalues of pencils of
  Hankel Gaussian random matrices and applications

abstract:
  Pencils of Hankel matrices whose elements have a joint Gaussian distribution
with nonzero mean and not identical covariance are considered. An approximation
to the distribution of the squared modulus of their determinant is computed
which allows to get a closed form approximation of the condensed density of the
generalized eigenvalues of the pencils. Implications of this result for solving
several moments problems are discussed and some numerical examples are
provided.


title:
Evolutionarily stable strategies of random games, and the vertices of
  random polygons

abstract:
  An evolutionarily stable strategy (ESS) is an equilibrium strategy that is
immune to invasions by rare alternative (``mutant'') strategies. Unlike Nash
equilibria, ESS do not always exist in finite games. In this paper we address
the question of what happens when the size of the game increases: does an ESS
exist for ``almost every large'' game? Letting the entries in the $n\times n$
game matrix be independently randomly chosen according to a distribution $F$,
we study the number of ESS with support of size $2.$ In particular, we show
that, as $n\to \infty$, the probability of having such an ESS: (i) converges to
1 for distributions $F$ with ``exponential and faster decreasing tails'' (e.g.,
uniform, normal, exponential); and (ii) converges to $1-1/\sqrt{e}$ for
distributions $F$ with ``slower than exponential decreasing tails'' (e.g.,
lognormal, Pareto, Cauchy). Our results also imply that the expected number of
vertices of the convex hull of $n$ random points in the plane converges to
infinity for the distributions in (i), and to 4 for the distributions in (ii).


title: $C^*$-algebras arising from substitutions

abstract:
  In this paper, we introduce a $C^{\ast}$-algebra associated with a proper
primitive substitution. We show that the $C^{\ast}$-algebra is simple and
purely infinite and contains the associated Cuntz-Krieger algebra and the
crossed product $C^{\ast}$-algebra of the corresponding Cantor minimal system.
We calculate the $K$-groups.


title: Gluon-Induced Weak Boson Fusion

abstract:
  The gluon-gluon induced terms for Higgs production through weak boson fusion
(WBF) are computed. Formally, these are of NNLO in the strong coupling
constant. This is the lowest order at which non-zero color exchange occurs
between the scattering quarks, leading to a color field and thus additional
hadronic activity between the outgoing jets. Using a minimal set of cuts, the
numerical impact of these terms is at the percent level with respect to the NLO
rate for weak boson fusion. Applying the so-called WBF cuts leads to an even
stronger suppression, so that we do not expect a significant deterioration of
the WFB signal by these color exchange effects.


title:
Analyticity of the SRB measure for holomorphic families of
  quadratic-like Collet-Eckmann maps

abstract:
  We show that if f_t is a holomorphic family of quadratic-like maps with all
periodic orbits repelling so that for each real t the map f_t is a real
Collet-Eckmann S-unimodal map then, writing m_t for the unique absolutely
continuous invariant probability measure of f_t, the map t -> \int g dm_t is
real analytic for any real analytic function g.


title:
Supercritical transition to turbulence in an inertially-driven von
  Karman closed flow

abstract:
  We study the transition from laminar flow to fully developed turbulence for
an inertially-driven von Karman flow between two counter-rotating large
impellers fitted with curved blades over a wide range of Reynolds number (100 -
1 000 000). The transition is driven by the destabilisation of the azimuthal
shear-layer, i.e., Kelvin-Helmholtz instability which exhibits
travelling/drifting waves, modulated travelling waves and chaos below the
emergence of a turbulent spectrum. A local quantity -the energy of the velocity
fluctuations at a given point- and a global quantity -the applied torque- are
used to monitor the dynamics. The local quantity defines a critical Reynolds
number Rec for the onset of time-dependence in the flow, and an upper
threshold/crossover Ret for the saturation of the energy cascade. The
dimensionless drag coefficient, i.e., the turbulent dissipation, reaches a
plateau above this finite Ret, as expected for a "Kolmogorov"-like turbulence
for Re -> infinity. Our observations suggest that the transition to turbulence
in this closed flow is globally supercritical: the energy of the velocity
fluctuations can be considered as an order parameter characterizing the
dynamics from the first laminar time-dependence up to the fully developed
turbulence. Spectral analysis in temporal domain moreover reveals that almost
all of the fluctuations energy is stored in time-scales one or two orders of
magnitude slower than the time-scale based on impeller frequency.


title: On higher derivative corrections of tachyon action

abstract:
  We have examined the momentum expansion of the disk level S-matrix element of
two tachyons and two gauge fields to find, up to on-shell ambiguity, the
couplings of these fields in the world volume theory of N coincident non-BPS
D-branes to all order of $\alpha'$. Using the proposal that the action of
D-brane-anti-D-brane is given by the projection of the action of two non-BPS
D-branes with $(-1)^{F_L}$, we find the corresponding couplings in the world
volume theory of the brane-anti-brane system. Using these infinite tower of
couplings, we then calculate the massless pole of the scattering amplitude of
one RR field, two tachyons and one gauge field in the brane-anti-brane theory.
We find that the massless pole of the field theory amplitude is exactly equal
to the massless pole of the disk level S-matrix element of one RR, two tachyons
and one gauge field to all order of $\alpha'$.


title:
PHANTOM: a Monte Carlo event generator for six parton final states at
  high energy colliders

abstract:
  PHANTOM is a tree level Monte Carlo for six parton final states at
proton--proton, proton--antiproton and electron--positron collider at
O(alpha_ew^6) and O(alpha_ew^4*alpha_s^2) including possible interferences
between the two sets of diagrams. This comprehends all purely electroweak
contribution as well as all contributions with one virtual or two external
gluons. It can generate unweighted events for any set of processes and it is
interfaced to parton shower and hadronization packages via the last Les Houches
Accord protocol. It can be used to analyze the physics of boson boson
scattering, Higgs boson production in boson boson fusion, t-tbar and three
boson production.


title: Photon pair production at flavour factories with per mille accuracy

abstract:
  We present a high-precision QED calculation, with 0.1% theoretical accuracy,
of two photon production in $e^+ e^-$ annihilation, as required by more and
more accurate luminosity monitoring at flavour factories. The accuracy of the
approach, which is based on the matching of exact next-to-leading order
corrections with a QED Parton Shower algorithm, is demonstrated through a
detailed analysis of the impact of the various sources of radiative corrections
to the experimentally relevant observables. The calculation is implemented in
the latest version of the event generator BabaYaga, available for precision
simulations of photon pair production at $e^+ e^-$ colliders of moderately high
energies.


title: Broken Symmetries from Minimally Doubled Fermions

abstract:
  Novel chirally symmetric fermion actions containing the minimum amount of
fermion doubling have been recently proposed in the literature. We study the
symmetries and renormalization of these actions and find that in each case,
discrete symmetries, such as parity and time-reversal, are explicitly broken.
Consequently, when the gauge interactions are included, these theories
radiatively generate relevant and marginal operators. Thus the restoration of
these symmetries and the approach to the continuum limit require the
fine-tuning of several parameters. With some assumptions, we show that this
behavior is unavoidable for actions displaying minimal fermion doubling.


title: AC electric trapping of neutral atoms

abstract:
  We study the dynamic behavior of ultracold neutral atoms in a macroscopic ac
electric trap. Confinement in such a trap is achieved by switching between two
saddle-point configurations of the electric field. The gradual formation of a
stably trapped cloud is observed and the trap performance is studied versus the
switching frequency and the symmetry of the switching cycle. Additionally, the
electric field in the trap is mapped out by imaging the atom cloud while the
fields are still on. Finally, the phase-space acceptance of the trap is probed
by introducing a modified switching cycle. The experimental results are
reproduced using full three-dimensional trajectory calculations.


title: Phase coherent transport in (Ga,Mn)As

abstract:
  Quantum interference effects and resulting quantum corrections of the
conductivity have been intensively studied in disordered conductors over the
last decades. The knowledge of phase coherence lengths and underlying dephasing
mechanisms are crucial to understand quantum corrections to the resistivity in
the different material systems. Due to the internal magnetic field and the
associated breaking of time-reversal symmetry quantum interference effects in
ferromagnetic materials have been scarcely explored. Below we describe the
investigation of phase coherent transport phenomena in the newly discovered
ferromagnetic semiconductor (Ga,Mn)As. We explore universal conductance
fluctuations in mesoscopic (Ga,Mn)As wires and rings, the Aharonov-Bohm effect
in nanoscale rings and weak localization in arrays of wires, made of the
ferromagnetic semiconductor material. The experiments allow to probe the phase
coherence length L_phi and the spin flip length L_SO as well as the temperature
dependence of dephasing.


title:
On Spacetimes with Given Kinematical Invariants: Construction and
  Examples

abstract:
  We present a useful method for the construction of cosmological models by
solving the differential equations arising from calculating the kinematical
invariants (shear, rotation, expansion and acceleration) of an observer field
in proper time description. As an application of our method we present two
generalizations of the G\"odel spacetime that follow naturally from our
approach.


title:
Quantum charges and spacetime topology: The emergence of new
  superselection sectors

abstract:
  In which is developed a new form of superselection sectors of topological
origin. By that it is meant a new investigation that includes several
extensions of the traditional framework of Doplicher, Haag and Roberts in local
quantum theories. At first we generalize the notion of representations of nets
of C*-algebras, then we provide a brand new view on selection criteria by
adopting one with a strong topological flavour. We prove that it is coherent
with the older point of view, hence a clue to a genuine extension. In this
light, we extend Roberts' cohomological analysis to the case where 1--cocycles
bear non trivial unitary representations of the fundamental group of the
spacetime, equivalently of its Cauchy surface in case of global hyperbolicity.
A crucial tool is a notion of group von Neumann algebras generated by the
1-cocycles evaluated on loops over fixed regions. One proves that these group
von Neumann algebras are localized at the bounded region where loops start and
end and to be factorial of finite type I. All that amounts to a new invariant,
in a topological sense, which can be defined as the dimension of the factor. We
prove that any 1-cocycle can be factorized into a part that contains only the
charge content and another where only the topological information is stored.
This second part resembles much what in literature are known as geometric
phases. Indeed, by the very geometrical origin of the 1-cocycles that we
discuss in the paper, they are essential tools in the theory of net bundles,
and the topological part is related to their holonomy content. At the end we
prove the existence of net representations.


title:
Non-Markovian diffusion over a parabolic potential barrier: influence of
  the friction-memory function

abstract:
  The over-passing probability across an inverted parabolic potential barrier
is investigated according to the classical and quantal generalized Langevin
equations. It is shown that, in the classical case, the asymptotic value of the
over-passing probability is determined by a single dominant root of the
"characteristic function", and it is given by a simple expression. The
expression for the over-passing probability is quite general, and details of
dissipation mechanism and memory effects enter into the expression only through
the dominant root of the characteristic equation.


title:
An Overview of the Bowen Survey; detecting donor star signatures in Low
  Mass X-ray Binaries

abstract:
  In this paper we give a review of the Bowen fluorescence survey, showing that
narrow emission lines (mainly NIII and CIII lines between 4630 and 4660 A)
appear to be universally present in the Bowen blend of optically bright low
mass X-ray binaries. These narrow lines are attributed to reprocessing in the
companion star giving the first estimates of K_2, and thereby providing the
first constraints on their system parameters. We will give an overview of the
constraints on the masses of the compact objects and briefly highlight the most
important results of the survey. Furthermore, we will point out the most
promising systems for future follow-up studies and indicate how we think their
estimates of the component masses can be improved.


title: On the Role of Viscosity in Early Cosmology

abstract:
  We present a discussion of the effects induced by bulk viscosity on the very
early Universe stability. The viscosity coefficient is assumed to be related to
the energy density $\rho$ via a power-law of the form $\zeta=\zeta_0 \rho^s$
(where $\zeta_0, s=const.$) and the behavior of the density contrast in
analyzed.
  In particular, we study both Einstein and hydrodynamic equations up to first
and second order in time in the so-called quasi-isotropic collapsing picture
near the cosmological singularity. As a result, we get a power-law solution
existing only in correspondence to a restricted domain of $\zeta_0$. The
particular case of pure isotropic FRW dynamics is then analyzed and we show how
the asymptotic approach to the initial singularity admits an unstable
collapsing picture.


title:
The Effect of Radiation Pressure on the Equilibrium Points in the
  Generalised Photogravitational Restricted Three Body Problem

abstract:
  The existence of equilibrium points and the effect of radiation pressure have
been discussed numerically. The problem is generalized by considering bigger
primary as a source of radiation and small primary as an oblate spheroid. We
have also discussed the Poynting-Robertson(P-R) effect which is caused due to
radiation pressure. It is found that the collinear points $L_1,L_2,L_3$ deviate
from the axis joining the two primaries, while the triangular points $L_4,L_5$
are not symmetrical due to radiation pressure. We have seen that $L_1,L_2,L_3$
are linearly unstable while $L_4,L_5$ are conditionally stable in the sense of
Lyapunov when P-R effect is not considered. We have found that the effect of
radiation pressure reduces the linear stability zones while P-R effect induces
an instability in the sense of Lyapunov.


title:
One-dimensional stepping stone models, sardine genetics and Brownian
  local time

abstract:
  Consider a one-dimensional stepping stone model with colonies of size $M$ and
per-generation migration probability $\nu$, or a voter model on $\mathbb{Z}$ in
which interactions occur over a distance of order $K$. Sample one individual at
the origin and one at $L$. We show that if $M\nu/L$ and $L/K^2$ converge to
positive finite limits, then the genealogy of the sample converges to a pair of
Brownian motions that coalesce after the local time of their difference exceeds
an independent exponentially distributed random variable. The computation of
the distribution of the coalescence time leads to a one-dimensional parabolic
differential equation with an interesting boundary condition at 0.


title:
Band-dependent normal-state coherence in Sr$_{2}$RuO$_{4}$: Evidence
  from Nernst effect and thermopower measurements

abstract:
  We present the first measurement on Nernst effect in the normal state of
odd-parity, spin-triplet superconductor Sr$_{2}$RuO$_{4}$. Below 100 K, the
Nernst signal was found to be negative, large, and, as a function of magnetic
field, nonlinear. Its magnitude increases with the decreasing temperature until
reaching a maximum around $T^*$ $\approx$ 20 - 25 K, below which it starts to
decrease linearly as a function of temperature. The large value of the Nernst
signal appears to be related to the multiband nature of the normal state and
the nonlinearity to band-dependent magnetic fluctuation in Sr$_{2}$RuO$_{4}$.
We argue that the sharp decrease in Nernst signal below $T^*$ is due to the
suppression of quasiparticle scattering and the emergence of band-dependent
coherence in the normal state. The observation of a sharp kink in the
temperature dependent thermopower around $T^*$ and a sharp drop of Hall angle
at low temperatures provide additional support to this picture.


title: A Geometrical Study of Matching Pursuit Parametrization

abstract:
  This paper studies the effect of discretizing the parametrization of a
dictionary used for Matching Pursuit decompositions of signals. Our approach
relies on viewing the continuously parametrized dictionary as an embedded
manifold in the signal space on which the tools of differential (Riemannian)
geometry can be applied. The main contribution of this paper is twofold. First,
we prove that if a discrete dictionary reaches a minimal density criterion,
then the corresponding discrete MP (dMP) is equivalent in terms of convergence
to a weakened hypothetical continuous MP. Interestingly, the corresponding
weakness factor depends on a density measure of the discrete dictionary.
Second, we show that the insertion of a simple geometric gradient ascent
optimization on the atom dMP selection maintains the previous comparison but
with a weakness factor at least two times closer to unity than without
optimization. Finally, we present numerical experiments confirming our
theoretical predictions for decomposition of signals and images on regular
discretizations of dictionary parametrizations.


title: Integrally closed and componentwise linear ideals

abstract:
  In two dimensional regular local rings integrally closed ideals have a unique
factorization property and have a Cohen-Macaulay associated graded ring. In
higher dimension these properties do not hold for general integrally closed
ideals and the goal of the paper is to identify a subclass of integrally closed
ideals for which they do. We restrict our attention to 0-dimensional
homogeneous ideals in polynomial rings $R$ of arbitrary dimension and identify
a class of integrally closed ideals, the Goto-class $\G^*$, that is closed
under product and that has a suitable unique factorization property. Ideals in
$\G^*$ have a Cohen-Macaulay associated graded ring if either they are monomial
or $\dim R\leq 3$. Our approach is based on the study of the relationship
between the notions of integrally closed, contracted, full and componentwise
linear ideals.


title: Cluster Dynamics of Planetary Waves

abstract:
  The dynamics of nonlinear atmospheric planetary waves is determined by a
small number of independent wave clusters consisting of a few connected
resonant triads. We classified the different types of connections between
neighboring triads that determine the general dynamics of a cluster. Each
connection type corresponds to substantially different scenarios of energy flux
among the modes. The general approach can be applied directly to various
mesoscopic systems with 3-mode interactions, encountered in hydrodynamics,
astronomy, plasma physics, chemistry, medicine, etc.


title: DBI-essence

abstract:
  Models where the dark energy is a scalar field with a non-standard
Dirac-Born-Infeld (DBI) kinetic term are investigated. Scaling solutions are
studied and proven to be attractors. The corresponding shape of the brane
tension and of the potential is also determined and found to be, as in the
standard case, either exponentials or power-law of the DBI field. In these
scenarios, in contrast to the standard situation, the vacuum expectation value
of the field at small redshifts can be small in comparison to the Planck mass
which could be an advantage from the model building point of view. This
situation arises when the present-day value of the Lorentz factor is large,
this property being per se interesting. Serious shortcomings are also present
such as the fact that, for simple potentials, the equation of state appears to
be too far from the observational favored value -1. Another problem is that,
although simple stringy-inspired models precisely lead to the power-law shape
that has been shown to possess a tracking behavior, the power index turns out
to have the wrong sign. Possible solutions to these issues are discussed.


title: Gauged Laplacians on quantum Hopf bundles

abstract:
  We study gauged Laplacian operators on line bundles on a quantum
2-dimensional sphere. Symmetry under the (co)-action of a quantum group allows
for their complete diagonalization. These operators describe `excitations
moving on the quantum sphere' in the field of a magnetic monopole. The energies
are not invariant under the exchange monopole/antimonopole, that is under
inverting the direction of the magnetic field. There are potential applications
to models of quantum Hall effect.


title:
A Dynamical Quantum Cluster Approach to Two-Particle Correlation
  Functions in the Hubbard Model

abstract:
  We investigate the charge- and spin dynamical structure factors for the 2D
one-band Hubbard model in the strong coupling regime within an extension of the
Dynamical Cluster Approximation (DCA) to two-particle response functions. The
full irreducible two-particle vertex with three momenta and frequencies is
approximated by an effective vertex dependent on the momentum and frequency of
the spin/charge excitation. In the spirit of the DCA, the effective vertex is
calculated with quantum Monte Carlo methods on a finite cluster. On the basis
of a comparison with high temperature auxiliary field quantum Monte Carlo data
we show that near and beyond optimal doping, our results provide a consistent
overall picture of the interplay between charge, spin and single-particle
excitations.


title:
Bounds for effective dielectric permittivity in differential medium
  approximation

abstract:
  Theoretical approach is proposed to description of dielectric properties of
matrix disperse systems which consists of dielectric matrix with embedded in
metallic inclusions. On the basis of effective differential medium
approximation the analytical expressions are obtained for the effective
dielectric permittivity of the matrix disperse system with inclusions of
spherical and ellipsoidal shape. The analysis of limits of possible values of
the real and imaginary parts of is carried out depending on system parameters.


title:
Saddle-shaped solutions of bistable diffusion equations in all of
  $\mathbb{R}^{2m}$

abstract:
  We study the existence and instability properties of saddle-shaped solutions
of the semilinear elliptic equation $-\Delta u = f(u)$ in the whole $\R^{2m}$,
where $f$ is of bistable type. It is known that in dimension $2m=2$ there
exists a saddle-shaped solution. This is a solution which changes sign in
$\R^2$ and vanishes only on $\{|x_1|=|x_2|\}$. It is also known that this
solution is unstable.
  In this article we prove the existence of saddle-shaped solutions in every
even dimension, as well as their instability in the case of dimension $2m=4$.
More precisely, our main result establishes that if $2m=4$, every solution
vanishing on the Simons cone $\{(x^1,x^2)\in\R^m\times\R^m : |x^1|=|x^2|\}$ is
unstable outside of every compact set and, as a consequence, has infinite Morse
index. These results are relevant in connection with a conjecture of De Giorgi
extensively studied in recent years and for which the existence of a
counter-example in high dimensions is still an open problem.


title:
Relating Recent Infection Prevalence to Incidence with a Sub-population
  of Non-progressors

abstract:
  We present a new analysis of relationships between disease incidence and the
prevalence of an experimentally defined state of `recent infection'. This leads
to a clean separation between biological parameters (properties of disease
progression as reflected in a test for recent infection), which need to be
calibrated, and epidemiological state variables, which are estimated in a
cross-sectional survey. The framework takes into account the possibility that
details of the assay and host/pathogen chemistry leave a (knowable) fraction of
the population in the recent category for all times. This systematically
addresses an issue which is the source of some controversy about the
appropriate use of the BED assay for defining recent HIV infection. Analysis of
relative contributions of error arising variously from statistical
considerations and simplifications of general expressions indicate that
statistical error dominates heavily over all sources of bias for realistic
epidemiological and biological scenarios. Numerical calculations validate the
approximations made in analytical relations.


title:
Ab-initio calculation of electronic stopping power along glancing swift
  heavy ion tracks in perovskites

abstract:
  In recent experiments the irradiation of insulators of perovskite type with
swift heavy ions under glancing incidence has been shown to provide a unique
means to generate periodically arranged nanodots at the surface. The physical
origin of these patterns has been suggested to stem from a highly anisotropic
electron density distribution within the bulk. In order to show the relevance
of the electron density distribution of the target we present a model
calculation for the system Xe$^{+23}$ $\to$ SrTiO$_{3}$ that is known to
produce the aforementioned surface modifications. On the basis of the Lindhard
model of electronic stopping, we employ highly-resolved \emph{ab-initio}
electron density data to describe the conversion of kinetic energy into
excitation energy along the ion track. The primary particle dynamics are
obtained via integration of the Newtonian equations of motion that are governed
by a space- and time-dependent friction force originating from Lindhard
stopping. The analysis of the local electronic stopping power along the ion
track reveals a pronounced periodic structure. The periodicity length strongly
varies with the particular choice of the polar angle of incidence and is
directly correlated to the experimentally observed formation of periodic
nanodots at insulator surfaces.


title:
Hepatocyte Aggregates: Methods of Preparation in the Microgravity
  Simulating Bioreactor Use in Tissue Engineering

abstract:
  Tissue Engineering concerns the three-dimensional cell growth so that
bio-artificial tissues could be created and used for transplantation. The
recently expressed concerns from the Tissue Engineering research community for
a re-direction of the research activities necessitate the proposition of new
methodologies. We propose a methodology that has to do with the simulation in
bioreactor systems of liver structures as are described in liver anatomy. I
this way the hepatocyte microenvironments that determine their function could
be re-created in vitro. The approach needs the use of hepatocyte aggregates as
entities to load the bioreactor systems. A new bioreactor, the microgravity
simulating rotation bioreactor, has been used for the preparation of cell
aggregates. Microcontact printing has been used to produce a patterned
surfaces. They were tested adsorbing BSA proteins, and will be used in future
for the mmobilization of cell aggregates in order to gain further understanding
of the role of cell heterogeneity in the cooperative behaviour of cells in
vitro.


title: Gerasimov's theorem and N-Koszul algebras

abstract:
  The paper is devoted to graded algebras having a single homogeneous relation.
Using Gerasimov's theorem, a criterion to be N-Koszul is given, providing new
examples. An alternative proof of Gerasimov's theorem for N=2 is given. Some
related results on Calabi-Yau algebras are proved.


title:
Cluster-variation approximation for a network-forming lattice-fluid
  model

abstract:
  We consider a 3-dimensional lattice model of a network-forming fluid, which
has been recently investigated by Girardi and coworkers by means of Monte Carlo
simulations [J. Chem. Phys. \textbf{126}, 064503 (2007)], with the aim of
describing water anomalies. We develop an approximate semi-analytical
calculation, based on a cluster-variation technique, which turns out to
reproduce almost quantitatively different thermodynamic properties and phase
transitions determined by the Monte Carlo method. Nevertheless, our calculation
points out the existence of two different phases characterized by long-range
orientational order, and of critical transitions between them and to a
high-temperature orientationally-disordered phase. Also, the existence of such
critical lines allows us to explain certain ``kinks'' in the isotherms and
isobars determined by the Monte Carlo analysis. The picture of the phase
diagram becomes much more complex and richer, though unfortunately less
suitable to describe real water.


title:
Constructing the supersymmetric Standard Model from intersecting
  D6-branes on the Z_6' orientifold

abstract:
  Intersecting stacks of supersymmetric fractional branes on the Z_6'
orientifold may be used to construct the supersymmetric Standard Model. If
$a,b$ are the stacks that generate the SU(3)_{colour} and SU(2)_L gauge
particles, then, in order to obtain just the chiral spectrum of the
(supersymmetric) Standard Model (with non-zero Yukawa couplings to the Higgs
mutiplets),it is necessary that the number of intersections $a \cap b$ of the
stacks $a$ and $b$, and the number of intersections $a \cap b'$ of $a$ with the
orientifold image $b'$ of $b$ satisfy $(a \cap b,a \cap b')=(2,1)$ or $(1,2)$.
It is also necessary that there is no matter in symmetric representations of
the gauge group, and not too much matter in antisymmetric representations, on
either stack. Fractional branes having all of these properties may be
constructed on the Z_6' orientifold. We provide a number of new examples having
these properties, some of which may be extended to give the Standard Model
spectrum. Specifically, we construct four-stack models with two further stacks,
each with just a single brane, which have the matter spectrum of the
supersymmetric Standard Model, including a single pair of Higgs doublets, {\em
plus} three right-chiral neutrino singlets. Ramond-Ramond tadpole cancellation
is achieved by the introduction of background H_3 flux, the 3-form field
strength associated with the Kalb-Ramond 2-form field B_2. There remains a
single unwanted gauged U(1)_{B-L}.


title: The mass structure of SU(3) multiplets and pion muon mass difference

abstract:
  The mass structure of hadron multiplets is understood to imply the
inexactness of SU(3) symmetry. Here we show that these symmetry broken mass
splittings amongst baryon and meson multiplet members are close integral
multiples of the mass difference between a neutral pion and a muon, the first
excitation within the elementary particle mass spectrum. This is found to be
equally true for the mass intervals amongst the particles belonging to the
multiplets having different spin and parity characteristics. The results
reinforce our earlier contention that the mass difference between a neutral
pion and a muon is of fundamental importance to the elementary particle mass
distribution.


title: Force networks and elasticity in granular silos

abstract:
  We have made experimental observations of the force networks within a
two-dimensional granular silo similar to the classical system of Janssen.
Models like that of Janssen predict that pressure within a silo saturates with
depth as the result of vertical forces being redirected to the walls of the
silo where they can then be carried by friction. By averaging ensembles of
experimentally-obtained force networks in different ways, we compare the
observed behavior with various predictions for granular silos. We identify
several differences between the mean behavior in our system and that predicted
by Janssen-like models: We find that the redirection parameter describing how
the force network transfers vertical forces to the walls varies with depth. We
find that changes in the preparation of the material can cause the pressure
within the silo to either saturate or to continue building with depth. Most
strikingly, we observe a non-linear response to overloads applied to the top of
the material in the silo. For larger overloads we observe the previously
reported "giant overshoot" effect where overload pressure decays only after an
initial increase [G. Ovarlez et al., Phys. Rev. E 67, 060302(R) (2003)]. For
smaller overloads we find that additional pressure propagates to great depth.
This effect depends on the particle stiffness, as given for instance by the
Young's modulus, E, of the material from which the particles are made.
Important measures include E, the unscreened hydrostatic pressure, and the
applied load. These experiments suggest that when the load and the particle
weight are comparable, particle elasticity acts to stabilize the force network,
allowing non-linear network effects to be seen in the mean behavior.


title: Hartree-Fock Interactions in the Integer Quantum Hall Effect

abstract:
  We report on numerical studies into the interplay of disorder and
electron-electron interactions within the integer quantum Hall regime, where
the presence of a strong magnetic field and two-dimensional confinement of the
electronic system profoundly affects thermodynamic and transport properties. We
emphasise the behaviour of the electronic compressibility, the local density of
states, and the Kubo conductivity. Our treatment of the electron-electron
interactions relies on the Hartree-Fock approximation so as to achieve system
sizes comparable to experimental situations. Our results clearly exhibit
manifestations of various interaction-mediated features, such as non-linear
screening, local charging, and g-factor enhancement, implying the inadequacy of
independent-particle models for comparison with experimental results.


title:
Evolution of arbitrary spin fields in the Schwarzschild-monopole
  spacetime

abstract:
  The quasinormal modes (QNMs) and the late-time behavior of arbitrary spin
fields are studied in the background of a Schwarzschild black hole with a
global monopole (SBHGM). It has been shown that the real part of the QNMs for a
SBHGM decreases as the symmetry breaking scale parameter $H$ increases but
imaginary part increases instead. For large overtone number $n$, these QNMs
become evenly spaced and the spacing for the imaginary part equals to
$-i(1-H)^{3/2}/(4M)$ which is dependent of $H$ but independent of the quantum
number $l$. It is surprisingly found that the late-time behavior is dominated
by an inverse power-law tail $t^{-2[1+\sqrt{(s+1/2)^{2}+ (l-s)(l+s+1)/(1-H)}]}$
for each $l$, and as $H\to0$ it reduces to the Schwarzschild case $t^{-(2l+3)}$
which is independent of the spin number $s$.


title: LQR-based coupling gain for synchronization of linear systems

abstract:
  Synchronization control of coupled continuous-time linear systems is studied.
For identical systems that are stabilizable, a linear feedback law obtained via
algebraic Riccati equation is shown to synchronize any fixed directed network
of any number of coupled systems provided that the coupling is strong enough.
The strength of coupling is determined by the smallest distance of a nonzero
eigenvalue of the coupling matrix to the imaginary axis. A dual problem where
detectable systems that are coupled via their outputs is also considered and
solved.


title: W-like states of N uncoupled spins 1/2

abstract:
  The exact dynamics of a disordered spin star system, describing a central
spin coupled to N distinguishable and non interacting spins 1/2, is reported.
Exploiting their interaction with the central single spin system, we present
possible conditional schemes for the generation of W-like states, as well as of
well-defined angular momentum states, of the N uncoupled spins. We provide in
addition a way to estimate the coupling intensity between each of the N spins
and the central one. Finally the feasibility of our procedure is briefly
discussed.


title: Influence of slab thickness on the Casimir force

abstract:
  We calculate the Casimir force between slabs of finite thickness made of
intrinsic and doped silicon with different concentration of carriers and
compare the results to those obtained for gold slabs. We use the Drude and the
plasma models to describe the dielectric function for the carriers in doped Si.
We discuss the possibility of experimentally testing the appropriateness of
these models. We also investigate the influence of finite thickness on $VO_2$,
which has recently been proposed for Casimir effect measurements testing the
metal-insulator transition.


title: Entanglement and the Quantum Brachistochrone Problem

abstract:
  Entanglement is closely related to some fundamental features of the dynamics
of composite quantum systems: quantum entanglement enhances the "speed" of
evolution of certain quantum states, as measured by the time required to reach
an orthogonal state. The concept of "speed" of quantum evolution constitutes an
important ingredient in any attempt to determine the fundamental limits that
basic physical laws impose on how fast a physical system can process or
transmit information. Here we explore the relationship between entanglement and
the speed of quantum evolution in the context of the quantum brachistochrone
problem. Given an initial and a final state of a composite system we consider
the amount of entanglement associated with the brachistochrone evolution
between those states, showing that entanglement is an essential resource to
achieve the alluded time-optimal quantum evolution.


title: Semi-regular Relative Difference Sets with Large Forbidden Subgroups

abstract:
  Motivated by a connection between semi-regular relative difference sets and
mutually unbiased bases, we study relative difference sets with parameters
$(m,n,m,m/n)$ in groups of non-prime-power orders. Let $p$ be an odd prime. We
prove that there does not exist a $(2p,p,2p,2)$ relative difference set in any
group of order $2p^2$, and an abelian $(4p,p,4p,4)$ relative difference set can
only exist in the group $\Bbb{Z}_2^2\times \Bbb{Z}_3^2$. On the other hand, we
construct a family of non-abelian relative difference sets with parameters
$(4q,q,4q,4)$, where $q$ is an odd prime power greater than 9 and $q\equiv 1$
(mod 4). When $q=p$ is a prime, $p>9$, and $p\equiv$ 1 (mod 4), the
$(4p,p,4p,4)$ non-abelian relative difference sets constructed here are
genuinely non-abelian in the sense that there does not exist an abelian
relative difference set with the same parameters.


title: Vector Matrices Realization of Hurwitz Algebras

abstract:
  We present the realization of Hurwitz algebras in terms of 2x2 vector
matrices, which maintain the correspondence between the geometry of the vector
spaces used in the classical physics and the underlined algebraic foundation of
the quantum theory. The multiplication rule used is modification of the one
originally introduced by M.Zorn. We demonstrate that our multiplication is not
intrinsically non-associative; the realization of the real and complex numbers
is commutative and associative, the real quaternions maintain associativity and
the real octonion matrices form an alternative algebra. The extension to the
calculus of the matrices (with Hurwitz algebra valued matrix elements) of the
arbitrary dimensions is straightforward. We discuss briefly the applications of
the obtained results to the extensions of the standard Hilbert space
formulation of the quantum physics and to the alternative wave mechanical
formulation of the classical field theory.


title: A local form for the automorphisms of the spectral unit ball

abstract:
  If F is an automorphism of the spectral unit ball, we show that, in a
neighborhood of any cyclic (i.e. non-derogatory) matrix of the ball, the map F
can be written as conjugation by a holomorphically varying non singular matrix.
This provides a shorter proof of a theorem of J. Rostand, with a slightly
stronger result.


title: Can very massive stars avoid Pair-Instability Supernovae?

abstract:
  Very massive primordial stars (140 Msol < M < 260 Msol) are supposed to end
their lives as PISN. Such an event can be traced by a typical chemical
signature in low metallicity stars, but at the present time, this signature is
lacking in the extremely metal-poor stars we are able to observe. Does it mean
that those very massive objects were not formed, contrarily to the primordial
star formation scenarios ? Could it be possible that they avoided this tragical
fate ?
  We explore the effects of rotation, anisotropical mass loss and magnetic
field on the core size of very massive Population III models. We find that
magnetic fields provide the strong coupling that is lacking in standard
evolution metal-free models and our 150 Msol Population III model avoids indeed
the pair-instability explosion.


title: Stability analysis of $\pi$-kinks in a 0-$\pi$ Josephson junction

abstract:
  We consider a spatially non-autonomous discrete sine-Gordon equation with
constant forcing and its continuum limit(s) to model a 0-$\pi$ Josephson
junction with an applied bias current. The continuum limits correspond to the
strong coupling limit of the discrete system. The non-autonomous character is
due to the presence of a discontinuity point, namely a jump of $\pi$ in the
sine-Gordon phase. The continuum models admits static solitary waves which are
called $\pi$-kinks and are attached to the discontinuity point. For small
forcing, there are three types of $\pi$-kinks. We show that one of the kinks is
stable and the others are unstable. There is a critical value of the forcing
beyond all static $\pi$-kinks fail to exist. Up to this value, the
(in)stability of the $\pi$-kinks can be established analytically in the strong
coupling limits. Applying a forcing above the critical value causes the
nucleation of $2\pi$-kinks and -antikinks. Besides a $\pi$-kink, the unforced
system also admits a static $3\pi$-kink. This state is unstable in the
continuum models. By combining analytical and numerical methods in the discrete
model, it is shown that the stable $\pi$-kink remains stable, and that the
unstable $\pi$-kinks cannot be stabilized by decreasing the coupling. The
$3\pi$-kink does become stable in the discrete model when the coupling is
sufficiently weak.


title:
Quantum Dynamics via Complex Analysis Methods: General Upper Bounds
  Without Time-Averaging and Tight Lower Bounds for the Strongly Coupled
  Fibonacci Hamiltonian

abstract:
  We develop further the approach to upper and lower bounds in quantum dynamics
via complex analysis methods which was introduced by us in a sequence of
earlier papers. Here we derive upper bounds for non-time averaged outside
probabilities and moments of the position operator from lower bounds for
transfer matrices at complex energies. Moreover, for the time-averaged
transport exponents, we present improved lower bounds in the special case of
the Fibonacci Hamiltonian. These bounds lead to an optimal description of the
time-averaged spreading rate of the fast part of the wavepacket in the large
coupling limit. This provides the first example which demonstrates that the
time-averaged spreading rates may exceed the upper box-counting dimension of
the spectrum.


title:
Extended Red Emission and the evolution of carbonaceaous nanograins in
  NGC 7023

abstract:
  Extended Red Emission (ERE) was recently attributed to the photo-luminescence
of either doubly ionized Polycyclic Aromatic Hydrocarbons (PAH$^{++}$), or
charged PAH dimers. We analysed the visible and mid-infrared (mid-IR) dust
emission in the North-West and South photo-dissociation regions of the
reflection nebula NGC 7023.Using a blind signal separation method, we extracted
the map of ERE from images obtained with the Hubble Space Telescope, and at the
Canada France Hawaii Telescope. We compared the extracted ERE image to the
distribution maps of the mid-IR emission of Very Small Grains (VSGs), neutral
and ionized PAHs (PAH$^0$ and PAH$^+$) obtained with the Spitzer Space
Telescope and the Infrared Space Observatory. ERE is dominant in transition
regions where VSGs are being photo-evaporated to form free PAH molecules, and
is not observed in regions dominated by PAH$^+$. Its carrier makes a minor
contribution to the mid-IR emission spectrum. These results suggest that the
ERE carrier is a transition species formed during the destruction of VSGs.
Singly ionized PAH dimers appear as good candidates but PAH$^{++}$ molecules
seem to be excluded.


title:
Instabilit\'{e} des cocycles d'\'{e}volution fortement mesurables dans
  des espaces de Banach

abstract:
  The aim of the paper is to present various asymptotic behaviors of
skew-evolution semiflows in Banach spaces, as exponential decay, instability,
exponential in- stability and integral instability. Relations between these
asymptotic properties are also given. As main results, two Datko type theorems
are proved. A unified nonuniform approach is provided.


title: On Generalized Uncertainty Principle

abstract:
  We study generalized uncertainty principle through the basic concepts of
limit and Fourier transformation and analyze both the quantum theory of gravity
and string theory from the perspective of complex function theory. Motivated
from the noncommutative nature of string theory, we have proposed a UV/IR
mixing dependent function $ \tilde{\delta}(\Delta x,\Delta k, \epsilon) $. For
a given $ \tilde{\delta}(\Delta x,\Delta k, \epsilon) $, we arrived at the
string uncertainty principle from the analyticity condition of a complex
function, which depends upon UV cut-off of the theory. This non trivially
modifies the quantum measurements, black hole physics and short distance
geometries. The present analysis is based on the postulate that the Planck
scale is the minimal length scale in nature. Furthermore, our consideration is
in perfect agreement with the existence of the maximum length scale in nature.
Both of the above length scales rely only upon the analysis of $
\tilde{\delta}(\Delta x,\Delta k, \epsilon) $ and do not directly make use of
any specific structure of the theory or Hamiltonian. The Regge behavior of the
string spectrum and the quantization of the horizon area of a black hole are
natural consequences of the function $ \tilde{\delta}(\Delta x,\Delta k,
\epsilon) $. It is hereby anticipated that $ \tilde{\delta}(\Delta x,\Delta k,
\epsilon) $ contains all possible corrections operating in nature, and thus a
promising possibility to reveal important clues towards the geometric origin of
$M$-theory.


title: Steady Hall Magnetohydrodynamics Near a X-type Magnetic Neutral Line

abstract:
  Hall magnetohydrodynamics (MHD) properties near a two-dimensional (2D) X-type
magnetic neutral line in the steady state are considered via heuristic and
rigorous developments. Upon considering the steady-state as the asymptotic
limit of the corresponding \textit{time-dependent} problem and using a rigorous
development, Hall effects are shown to be able to sustain the hyperbolicity of
the magnetic field (and hence a more open X-point configuration) near the
neutral line in the steady state. The heuristic development misses this subtle
connection of the steady state with the corresponding \textit{time-dependent}
problem and predicts only an elongated current-sheet configuration (as in
resistive MHD). However, the heuristic development turns out to be useful in
providing insight into the lack of dependence of the reconnection rate on the
mechanism breaking the frozen-in condition of the magnetic field lines. The
latter result can be understood in terms of the ability of the ions and
electrons to transport equal amounts of magnetic flux per unit time out of the
reconnection region.


title:
Tensor, Sobolev, Multiplicative and Convolution Operators in the Bide -
  Side Grand Lebesque Spaces

abstract:
  In this paper we study the multiplicative, tensor, Sobolev's and convolution
inequalities in certain Banach spaces, the so-called Bide - Side Grand Lebesque
Spaces, and give examples to show their sharpness.


title: X-Ray Transitions from Antiprotonic Noble Gases

abstract:
  The onset of antiprotonic X-ray transitions at high principal quantum numbers
and the occurence of electronic X-rays in antiprotonic argon, krypton, and
xenon has been analyzed with the help of Multiconfiguration Dirac-Fock
calculations. The shell-by-shell ionisation by Auger electron emission,
characterised by appearance and disappearance of X-ray lines, is followed
through the antiprotonic cascade by considering transition and binding energies
of both the antiproton and the remaining electrons. Electronic lines could be
attributed partly to specific states of the antiprotonic atom de-excitation.


title:
Surface-hopping dynamics and decoherence with quantum equilibrium
  structure

abstract:
  In open quantum systems decoherence occurs through interaction of a quantum
subsystem with its environment. The computation of expectation values requires
a knowledge of the quantum dynamics of operators and sampling from initial
states of the density matrix describing the subsystem and bath. We consider
situations where the quantum evolution can be approximated by quantum-classical
Liouville dynamics and examine the circumstances under which the evolution can
be reduced to surface-hopping dynamics, where the evolution consists of
trajectory segments evolving exclusively on single adiabatic surfaces, with
probabilistic hops between these surfaces. The justification for the reduction
depends on the validity of a Markovian approximation on a bath averaged memory
kernel that accounts for quantum coherence in the system. We show that such a
reduction is often possible when initial sampling is from either the quantum or
classical bath initial distributions. If the average is taken only over the
quantum dispersion that broadens the classical distribution, then such a
reduction is not always possible.


title: Tests of general relativity in the solar system

abstract:
  Tests of gravity performed in the solar system show a good agreement with
general relativity. The latter is however challenged by observations at larger,
galactic and cosmic, scales which are presently cured by introducing "dark
matter" or "dark energy". A few measurements in the solar system, particularly
the so-called "Pioneer anomaly", might also be pointing at a modification of
gravity law at ranges of the order of the size of the solar system. The present
lecture notes discuss the current status of tests of general relativity in the
solar system. They describe metric extensions of general relativity which have
the capability to preserve compatibility with existing gravity tests while
opening free space for new phenomena. They present arguments for new mission
designs and new space technologies as well as for having a new look on data of
existing or future experiments.


title:
On the expressive power of permanents and perfect matchings of matrices
  of bounded pathwidth/cliquewidth

abstract:
  Some 25 years ago Valiant introduced an algebraic model of computation in
order to study the complexity of evaluating families of polynomials. The theory
was introduced along with the complexity classes VP and VNP which are analogues
of the classical classes P and NP. Families of polynomials that are difficult
to evaluate (that is, VNP-complete) includes the permanent and hamiltonian
polynomials. In a previous paper the authors together with P. Koiran studied
the expressive power of permanent and hamiltonian polynomials of matrices of
bounded treewidth, as well as the expressive power of perfect matchings of
planar graphs. It was established that the permanent and hamiltonian
polynomials of matrices of bounded treewidth are equivalent to arithmetic
formulas. Also, the sum of weights of perfect matchings of planar graphs was
shown to be equivalent to (weakly) skew circuits. In this paper we continue the
research in the direction described above, and study the expressive power of
permanents, hamiltonians and perfect matchings of matrices that have bounded
pathwidth or bounded cliquewidth. In particular, we prove that permanents,
hamiltonians and perfect matchings of matrices that have bounded pathwidth
express exactly arithmetic formulas. This is an improvement of our previous
result for matrices of bounded treewidth. Also, for matrices of bounded
weighted cliquewidth we show membership in VP for these polynomials.


title: The rigidity of embedded constant mean curvature surfaces

abstract:
  We study the rigidity of complete, embedded constant mean curvature surfaces
in R^3. Among other things, we prove that when such a surface has finite genus,
then intrinsic isometries of the surface extend to isometries of R^3 or its
isometry group contains an index two subgroup of isometries that extend.


title: When every multilinear mapping is multiple summing

abstract:
  In this paper we give a systematized treatment to some coincidence situations
for multiple summing multilinear mappings which extend, generalize and simplify
the methods and results obtained thus far. The application of our general
results to the pertinent particular cases gives several new coincidences as
well as easier proofs of some known results.


title: Gravitational waves, diffusion and decoherence

abstract:
  The quite different behaviors exhibited by microscopic and macroscopic
systems with respect to quantum interferences suggest that there may exist a
naturally frontier between quantum and classical worlds. The value of the
Planck mass (22$\mu$g) may lead to the idea of a connection between this
borderline and intrinsic fluctuations of spacetime. We show that it is possible
to obtain quantitative answers to these questions by studying the diffusion and
decoherence mechanisms induced on quantum systems by gravitational waves
generated at the galactic or cosmic scales. We prove that this universal
fluctuating environment strongly affects quantum interferences on macroscopic
systems, while leaving essentially untouched those on microscopic systems. We
obtain the relevant parameters which, besides the ratio of the system's mass to
Planck mass, characterize the diffusion constant and decoherence time. We
discuss the feasibility of experiments aiming at observing these effects in the
context of ongoing progress towards more and more sensitive matter-wave
interferometry.


title:
Invariant manifolds as building blocks for the formation of spiral arms
  and rings in barred galaxies

abstract:
  We propose a theory to explain the formation of spiral arms and of all types
of outer rings in barred galaxies, extending and applying the technique used in
celestial mechanics to compute transfer orbits. Thus, our theory is based on
the chaotic orbital motion driven by the invariant manifolds associated to the
periodic orbits around the hyperbolic equilibrium points. In particular, spiral
arms and outer rings are related to the presence of heteroclinic or homoclinic
orbits. Thus, R1 rings are associated to the presence of heteroclinic orbits,
while R1R2 rings are associated to the presence of homoclinic orbits. Spiral
arms and R2 rings, however, appear when there exist neither heteroclinic nor
homoclinic orbits. We examine the parameter space of three realistic, yet
simple, barred galaxy models and discuss the formation of the different
morphologies according to the properties of the galaxy model. The different
morphologies arise from differences in the dynamical parameters of the galaxy.


title:
Finite speed of propagations of the electromagnetic field in nonlinear
  isotropic dispersive mediums

abstract:
  We propose some modification of Maxwell's equations describing mediums which
electric and magnetic properties are changed essentially after interaction with
outer electromagnetic field. We show for such mediums that electromagnetic
waves have finite speed of propagations property for some time depending on
initial energy of electromagnetic field and nonlinear parameters of the problem
which are responsible for properties of medium.


title: Dynamical Blueprints for Galaxies

abstract:
  We present an axisymmetric, equilibrium model for late-type galaxies which
consists of an exponential disk, a Sersic bulge, and a cuspy dark halo. The
model is specified by a phase space distribution function which, in turn,
depends on the integrals of motion. Bayesian statistics and the Markov Chain
Monte Carlo method are used to tailor the model to satisfy observational data
and theoretical constraints. By way of example, we construct a chain of 10^5
models for the Milky Way designed to fit a wide range of photometric and
kinematic observations. From this chain, we calculate the probability
distribution function of important Galactic parameters such as the Sersic index
of the bulge, the disk scale length, and the disk, bulge, and halo masses. We
also calculate the probability distribution function of the local dark matter
velocity dispersion and density, two quantities of paramount significance for
terrestrial dark matter detection experiments.
  Though the Milky Way models in our chain all satisfy the prescribed
observational constraints, they vary considerably in key structural parameters
and therefore respond differently to non-axisymmetric perturbations. We
simulate the evolution of twenty-five models which have different Toomre Q and
Goldreich-Tremaine X parameters. Virtually all of these models form a bar,
though some, more quickly than others. The bar pattern speeds are ~ 40 - 50
km/s/kpc at the time when they form and then decrease, presumably due to
coupling of the bar with the halo. Since the Galactic bar has a pattern speed
~50 km/s/kpc we conclude that it must have formed recently.


title: Approximate and pseudo-amenability of various classes of Banach algebras

abstract:
  We continue the investigation of notions of approximate amenability that were
introduced in work of the second and third authors. It is shown that every
boundedly approximately contractible Banach algebra has a bounded approximate
identity.
  Among our other results, it is shown that the Fourier algebra of the free
group on two generators is not approximately amenable. Further examples are
obtained of ${\ell}^1$-semigroup algebras which are approximately amenable but
not amenable; using these, we show that bounded approximate amenability need
not imply sequential approximate amenability. Results are also given for Segal
subalgebras of $L^1(G)$, where $G$ is a locally compact group, and the algebras
$PF_p(\Gamma)$ of $p$-pseudofunctions on a discrete group $\Gamma$ (of which
the reduced $C^*$-algebra is a special case).


title:
Convergence of finite-dimensional laws of the weighted quadratic
  variations process for some fractional Brownian sheets

abstract:
  In this paper we state and prove a central limit theorem for the
finite-dimensional laws of the quadratic variations process of certain
fractional Brownian sheets. The main tool of this article is a method developed
by Nourdin and Nualart based on the Malliavin calculus.


title:
Thermodynamics and critical behavior in the Nambu-Jona-Lasinio model of
  QCD

abstract:
  We investigate the phase diagram of strongly interacting matter as a function
of temperature and baryonic density/chemical potential, within
Nambu--Jona-Lasinio type models. We perform a systematic study concerning the
existence, location, and properties of a critical end point/tricritical point,
both in SU(2) and SU(3) versions of the model. We verify that, for $m_u=m_d=0$
and up to a critical strange quark mass, there is a tricritical point, which
becomes a critical end point in a world with realistic values of the current
quark masses. The properties of physical observables, such as the baryon number
susceptibility and the specific heat, are analyzed in the vicinity of the
critical end point, with special focus on their critical exponents. The
behavior of mesons in the $T-\mu_B(\rho_B)$ plane is analyzed in connection
with possible signatures of partial and effective restoration of chiral
symmetry.


title:
Measurement of Charm Production Cross Sections in e+e- Annihilation at
  Energies between 3.97 and 4.26 GeV

abstract:
  Using the CLEO-c detector at the Cornell Electron Storage Ring, we have
measured inclusive and exclusive cross sections for the production of D+, D0
and Ds+ mesons in e+e- annihilations at thirteen center-of-mass energies
between 3.97 and 4.26 GeV. Exclusive cross sections are presented for final
states consisting of two charm mesons (DD, D*D, D*D*, Ds+Ds-, Ds*+Ds-, and
Ds*+Ds*-) and for processes in which the charm-meson pair is accompanied by a
pion. No enhancement in any final state is observed at the energy of the
Y(4260).


title: Impurity modes and effect of clustering in diluted semiconductor alloys

abstract:
  The variation of TO zone-center vibration spectra with concentration in mixed
zincblende-type semiconductors can be understood within a paradigm of unified
"one bond - two modes" approach, which has been recently outlined as a rather
general concept, and emerges from a number of previous experimental and
theoretical studies. The crucial issue is that the vibration frequency,
associated with a certain cation-anion bond, depends on the length of the
latter, and the bond length, in its turn, depends not only on the average alloy
concentration, but on local variations of it. In an (A,B)C substitutional
alloy, the A-C bond length differ in A-rich and A-poor regions, yielding a
splitting of the A-C vibration frequency. Such splittings can be measured and
reproduced in first-principles calculations.
  An analysis of vibration spectra helps to get an insight into the structural
short-range (clustering) and long-range (formation of extended chains of
certain cation-anion pairs and other structural motives at the mesoscopic
scale) tendencies. For this however, one needs first-principles benchmark
calculations for representative model systems. The simplest yet important
result from first-principles calculations is a prediction of how the impurity
phonon mode evolves as isolated (distant) impurities get clustered.


title: Is dark energy an effect of averaging?

abstract:
  The present standard model of cosmology states that the known particles carry
only a tiny fraction of total mass and energy of the Universe. Rather, unknown
dark matter and dark energy are the dominant contributions to the cosmic energy
budget. We review the logic that leads to the postulated dark energy and
present an alternative point of view, in which the puzzle may be solved by
properly taking into account the influence of cosmic structures on global
observables. We illustrate the effect of averaging on the measurement of the
Hubble constant.


title:
Controlling the self-doping of YBa2C3O7-d polar surfaces: From Fermi
  surface to nodal Fermi arcs by ARPES

abstract:
  The discovery of quantum oscillations in the normal-state electrical
resistivity of YBa2Cu3O6.5 provides the first evidence for the existence of
Fermi surface (FS) pockets in an underdoped cuprate. However, the pockets'
electron vs. hole character, and the very interpretation in terms of closed FS
contours, are the subject of considerable debate. Angle-resolved photoemission
spectroscopy (ARPES), with its ability to probe electronic dispersion as well
as the FS, is ideally suited to address this issue. Unfortunately, the ARPES
study of YBa2C3O7-d (YBCO) has been hampered by the technique's surface
sensitivity. Here we show that this stems from the polarity and corresponding
self-doping of the YBCO surface. By in-situ deposition of potassium atoms on
the cleaved surface, we are able to continuously tune the doping of a single
sample from the heavily overdoped to the underdoped regime. This reveals the
progressive collapse of the normal-metal-like FS into four disconnected nodal
FS arcs, or perhaps into hole but not electron pockets, in underdoped YBCO6.5.


title: Submillimeter Spectrum of Formic Acid

abstract:
  We have measured new submillimeter-wave data around 600 GHz and around 1.1
THz for the 13C isotopologue of formic acid and for the two deuterium
isotopomers; in each case for both the trans and cis rotamer. For cis-DCOOH and
cis-HCOOD in particular only data up to 50 GHz was previously available. For
all species the quality and quantity of molecular parameters has been increased
providing new measured frequencies and more precise and reliable frequencies in
the range of existing and near-future submillimeter and far-infrared
astronomical spectroscopy instruments such as Herschel, SOFIA and ALMA.


title: Automorphism groups of algebraic curves with p-rank zero

abstract:
  In positive characteristic, algebraic curves can have many more automorphisms
than expected from the classical Hurwitz's bound. There even exist algebraic
curves of arbitrary high genus g with more than 16g^4 automorphisms. It has
been observed on many occasions that the most anomalous examples invariably
have zero p-rank. In this paper, the K-automorphism group Aut(X) of a zero
2-rank algebraic curve X defined over an algebraically closed field K of
characteristic 2 is investigated. The main result is that if the curve has
genus g greater than or equal to 2, and |Aut(X)|>24g^2, then Aut(X) has a fixed
point on X, apart from few exceptions. In the exceptional cases the
possibilities for Aut(X) and g are determined.


title:
Critical temperature of interacting Bose gases in two and three
  dimensions

abstract:
  We calculate the superfluid transition temperature of homogeneous interacting
Bose gases in three and two spatial dimensions using large-scale Path Integral
Monte Carlo simulations (with up to $N=10^5$ particles). In 3D we investigate
the limits of the universal critical behavior in terms of the scattering length
alone by using different models for the interatomic potential. We find that
this type of universality sets in at small values of the gas parameter $na^3
\lesssim 10^{-4}$. This value is different from the estimate $na^3 \lesssim
10^{-6}$ for the validity of the asymptotic expansion in the limit of vanishing
$na^3$. In 2D we study the Berezinskii-Kosterlitz-Thouless transition of a gas
with hard-core interactions. For this system we find good agreement with the
classical lattice $|\psi|^4$ model up to very large densities. We also explain
the origin of the existing discrepancy between previous studies of the same
problem.


title: Geodesic-invariant equations of gravitation

abstract:
  Einstein's equations of gravitation are not invariant under geodesic
mappings, i. e. under a certain class of mappings of the Christoffel symbols
and the metric tensor which leave the geodesic equations in a given coordinate
system invariant. A theory in which geodesic mappings play the role of gauge
transformations is considered.


title:
Phase structure, critical points and susceptibilities in
  Nambu-Jona-Lasinio type models

abstract:
  We investigate the chiral phase transition at finite temperature and chemical
potential within SU(2) and SU(3) Nambu-Jona-Lasinio type models. The behavior
of the baryon number susceptibility and the specific heat, in the vicinity of
the critical end point, is studied. The class of the critical points is
analyzed by calculating critical exponents.


title: Pulsar wind zone processes in LS 5039

abstract:
  Several $\gamma$-ray binaries have been recently detected by the High-Energy
Stereoscopy Array (H.E.S.S.) and the Major Atmospheric Imaging Cerenkov (MAGIC)
telescope. In at least two cases, their nature is unknown. In this paper we aim
to provide the details of a theoretical model of close $\gamma$-ray binaries
containing a young energetic pulsar as compact object, earlier presented in
recent Letters. This model includes a detailed account of the system geometry,
the angular dependence of processes such as Klein-Nishina inverse Compton and
$\gamma\gamma$ absorption in the anisotropic radiation field of the massive
star, and a Monte Carlo simulation of leptonic cascading. We present and derive
the used formulae and give all details about their numerical implementation,
particularly, on the computation of cascades. In this model, emphasis is put in
the processes occurring in the pulsar wind zone of the binary, since, as we
show, opacities in this region can be already important for close systems. We
provide a detailed study on all relevant opacities and geometrical dependencies
along the orbit of binaries, exemplifying with the case of LS 5039. This is
used to understand the formation of the very high-energy lightcurve and phase
dependent spectrum. For the particular case of LS 5039, we uncover an
interesting behavior of the magnitude representing the shock position in the
direction to the observer along the orbit, and analyze its impact in the
predictions. We show that in the case of LS 5039, the H.E.S.S. phenomenology is
matched by the presented model, and explore the reasons why this happens while
discussing future ways of testing the model.


title:
Nonlinear dynamics of Bose-condensed gases by means of a low- to
  high-density variational approach

abstract:
  We propose a versatile variational method to investigate the spatio-temporal
dynamics of one-dimensional magnetically-trapped Bose-condensed gases. To this
end we employ a \emph{q}-Gaussian trial wave-function that interpolates between
the low- and the high-density limit of the ground state of a Bose-condensed
gas. Our main result consists of reducing the Gross-Pitaevskii equation, a
nonlinear partial differential equation describing the T=0 dynamics of the
condensate, to a set of only three equations: \emph{two coupled nonlinear
ordinary differential equations} describing the phase and the curvature of the
wave-function and \emph{a separate algebraic equation} yielding the generalized
width. Our equations recover those of the usual Gaussian variational approach
(in the low-density regime), and the hydrodynamic equations that describe the
high-density regime. Finally, we show a detailed comparison between the
numerical results of our equations and those of the original Gross-Pitaevskii
equation.


title:
Searching for stochastic gravitational-wave background with the
  co-located LIGO interferometers

abstract:
  This paper presents techniques developed by the LIGO Scientific Collaboration
to search for the stochastic gravitational-wave background using the co-located
pair of LIGO interferometers at Hanford, WA. We use correlations between
interferometers and environment monitoring instruments, as well as time-shifts
between two interferometers (described here for the first time) to identify
correlated noise from non-gravitational sources. We veto particularly noisy
frequency bands and assess the level of residual non-gravitational coupling
that exists in the surviving data.


title:
Galaxy-cluster gas-density distributions of the Representative
  XMM-Newton Cluster Structure Survey (REXCESS)

abstract:
  We present a study of the structural and scaling properties of the gas
distributions in the intracluster medium (ICM) of 31 nearby (z < 0.2) clusters
observed with XMM-Newton, which together comprise the Representative XMM-Newton
Cluster Structure Survey (REXCESS). In contrast to previous studies, this
sample is unbiased with respect to cluster dynamical state, and it fully
samples the cluster X-ray luminosity function. The clusters cover a temperature
range of 2.0 -- 8.5 keV and possess a variety of morphologies. The sampling
strategy allows us to compare clusters with a wide range of central cooling
times on an equal footing. We present non-parametric gas-density profiles out
to distances ranging between 0.8 R_500 and 1.5 R_500. The central gas densities
differ greatly from system to system, with no clear correlation with system
temperature. At intermediate radii the scaled density profiles show much less
scatter, with a clear dependence on system temperature, consistent with the
presence of an entropy excess as suggested in previous literature. However, at
large scaled radii this dependence becomes weaker: clusters with kT > 3 keV
scale self-similarly, with no temperature dependence of gas-density
normalisation. We find some evidence of a correlation between dynamical state
and outer gas density slope, and between dynamical state and both central gas
normalisation and cooling time. We find no evidence of a significant bimodality
in the distributions of central density, density gradient, or cooling time.
Finally, we present the gas mass-temperature relation for the REXCESS sample,
which is consistent with the expectation of self-similar scaling modified by
the presence of an entropy excess in the inner regions of the cluster, and has
a logarithmic intrinsic scatter of ~10%.


title: The modified Calabi-Yau problems for CR-manifolds and applications

abstract:
  In this paper, we derive a partial result related to a question of Yau: "Does
a simply-connected complete K\"ahler manifold M with negative sectional
curvature admit a bounded non-constant holomorphic function?"
  Main Theorem. Let $M^{2n}$ be a simply-connected complete K\"ahler manifold M
with negative sectional curvature $ \le -1 $ and $S_\infty(M)$ be the sphere at
infinity of $M$. Then there is an explicit {\it bounded} contact form $\beta$
defined on the entire manifold $M^{2n}$.
  Consequently, the sphere $S_\infty(M)$ at infinity of M admits a {\it
bounded} contact structure and a bounded pseudo-Hermitian metric in the sense
of Tanaka-Webster.
  We also discuss several open modified problems of Calabi and Yau for
Alexandrov spaces and CR-manifolds.


title:
Difference Imaging of Lensed Quasar Candidates in the SDSS Supernova
  Survey Region

abstract:
  Difference imaging provides a new way to discover gravitationally lensed
quasars because few non-lensed sources will show spatially extended, time
variable flux. We test the method on lens candidates in the Sloan Digital Sky
Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS)
and their surrounding fields. Starting from 20768 sources, including 49 SDSS
quasars and 36 candidate lenses/lensed images, we find that 21 sources
including 15 SDSS QSOs and 7 candidate lenses/lensed images are non-periodic
variable sources. We can measure the spatial structure of the variable flux for
18 of these sources and identify only one as a non-point source. This source
does not display the compelling spatial structure of the variable flux of known
lensed quasars, so we reject it as a lens candidate. None of the lens
candidates from the SQLS survive our cuts. Given our effective survey area of
order 0.71 square degrees, this indicates a false positive rate of order one
per square degree for themethod. The fraction of quasars not found to be
variable and the false positive rate should both fall if we analyze the full,
later data releases for the SDSS fields. While application of the method to the
SDSS is limited by the resolution, depth, and sampling of the survey, several
future surveys such as Pan-STARRS, LSST, and SNAP will avoid these limitations.


title: Evolution of low-mass binaries with black-hole components

abstract:
  We consider evolutionary models for the population of short-period (<10 hr)
low-mass black-hole binaries (LMBHB) and compare them with observations of soft
X-ray transients (SXT). Evolution of LMBHB is determined by nuclear evolution
of the donors and/or orbital angular momentum loss due to magnetic braking by
the stellar wind of the donors and gravitational wave radiation. We show that
the absence of observed stable luminous LMBHB implies that upon RLOF by the
low-mass donor angular momentum losses are substantially reduced with respect
to the Verbunt and Zwaan "standard" prescription for magnetic braking. Under
this assumption masses and effective temperatures of the model secondaries of
LMBHB are in a satisfactory agreement with the masses and effective
temperatures (as inferred from their spectra) of the observed donors in LMBHB.
Theoretical mass-transfer rates in SXTs are consistent with the observed ones
if one assumes that accretion discs in these systems are truncated ("leaky").
We find that the population of short-period SXT is formed mainly by systems
which had unevolved or slightly evolved (X_c > 0.35) donors at the RLOF. Longer
period (0.5 - 1 day) SXT might descend from systems with initial donor mass
about 1 solar and X_c < 0.35. It is unnecessary to invoke donors with almost
hydrogen-depleted cores to explain the origin of LMBHB. Our models suggest that
a very high efficiency of common-envelopes ejection is necessary to form LMBHB,
unless currently commonly accepted empirical estimates of mass-loss rates by
winds for pre-WR and WR-stars are significantly over-evaluated.


title: Finding central decompositions of p-groups

abstract:
  Polynomial-time algorithms are given to find a central decomposition of
maximum size for a finite p-group of class 2 and for a nilpotent Lie ring of
class 2. The algorithms use Las Vegas probabilistic routines to compute the
structure of finite *-rings and also the Las Vegas C-MeatAxe. When p is small,
the probabilistic methods can be replaced by deterministic polynomial-time
algorithms.
  The methods introduce new group isomorphism invariants including new
characteristic subgroups.


title:
A mean-field version of the Nicodemi-Prisco SSB model for X-chromosome
  inactivation

abstract:
  Nicodemi and Prisco recently proposed a model for X-chromosome inactivation
in mammals, explaining this phenomenon in terms of a spontaneous
symmetry-breaking mechanism [{\it Phys. Rev. Lett.} 99 (2007), 108104]. Here we
provide a mean-field version of their model.


title: Model for Diffusion-Induced Ramsey Narrowing

abstract:
  Diffusion-induced Ramsey narrowing that appears when atoms can leave the
interaction region and repeatedly return without lost of coherence is
investigated using strong collisions approximation. The effective diffusion
equation is obtained and solved for low-dimensional model configurations and
three-dimensional real one.


title:
Damped Bloch Oscillations of Bose-Einstein Condensates in Disordered
  Potential Gradients

abstract:
  We investigate both experimentally and theoretically disorder induced damping
of Bloch oscillations of Bose-Einstein condensates in optical lattices. The
spatially inhomogeneous force responsible for the damping is realised by a
combination of a disordered optical and a magnetic gradient potential. We show
that the inhomogeneity of this force results in a broadening of the
quasimomentum spectrum, which in turn causes damping of the centre-of-mass
oscillation. We quantitatively compare the obtained damping rates to the
simulations using the Gross-Pitaevskii equation. Our results are relevant for
high precision experiments on very small forces, which require the observation
of a large number of oscillation cycles.


title: Duality in random matrix ensembles for all Beta

abstract:
  Gaussian and Chiral Beta-Ensembles, which generalise well known orthogonal
(Beta=1), unitary (Beta=2), and symplectic (Beta=4) ensembles of random
Hermitian matrices, are considered. Averages are shown to satisfy duality
relations like {Beta,N,n} <--> {4/Beta,n,N} for all Beta>0, where N and n
respectively denote the number of eigenvalues and products of characteristic
polynomials. At the edge of the spectrum, matrix integrals of the Airy
(Kontsevich) type are obtained. Consequences on the integral representation of
the multiple orthogonal polynomials and the partition function of the formal
one-matrix model are also discussed. Proofs rely on the theory of multivariate
symmetric polynomials, especially Jack polynomials.


title: Benchmark calculations for reduced density-matrix functional theory

abstract:
  Reduced density-matrix functional theory (RDMFT) is a promising alternative
approach to the problem of electron correlation. Like standard density
functional theory, it contains an unknown exchange-correlation functional, for
which several approximations have been proposed in the last years. In this
article, we benchmark some of these functionals in an extended set of molecules
with respect to total and atomization energies. Our results show that the most
recent RDMFT functionals give very satisfactory results compared to more
involved quantum chemistry and density functional approaches.


title: Heavy Dark Matter Through the Higgs Portal

abstract:
  Motivated by Higgs Portal and Hidden Valley models, heavy particle dark
matter that communicates with the supersymmetric Standard Model via pure Higgs
sector interactions is considered. We show that a thermal relic abundance
consistent with the measured density of dark matter is possible for masses up
to $\sim 30\tev$. For dark matter masses above $\sim 1\tev$, non-perturbative
Sommerfeld corrections to the annihilation rate are large, and have the
potential to greatly affect indirect detection signals. For large dark matter
masses, the Higgs-dark-matter-sector couplings are large and we show how such
models may be given a UV completion within the context of so-called "Fat-Higgs"
models. Higgs Portal dark matter provides an example of an attractive
alternative to conventional MSSM neutralino dark matter that may evade
discovery at the LHC, while still being within the reach of current and
upcoming indirect detection experiments.


title: Collins Asymmetry at Hadron Colliders

abstract:
  We study the Collins effect in the azimuthal asymmetric distribution of
hadrons inside a high energy jet in the single transverse polarized proton
proton scattering. From the detailed analysis of one-gluon and two-gluon
exchange diagrams contributions, the Collins function is found the same as that
in the semi-inclusive deep inelastic scattering and e^+e^- annihilations. The
eikonal propagators in these diagrams do not contribute to the phase needed for
the Collins-type single spin asymmetry, and the universality is derived as a
result of the Ward identity. We argue that this conclusion depends on the
momentum flow of the exchanged gluon and the kinematic constraints in the
fragmentation process, and is generic and model-independent.


title:
Bayesian models to adjust for response bias in survey data for
  estimating rape and domestic violence rates from the NCVS

abstract:
  It is difficult to accurately estimate the rates of rape and domestic
violence due to the sensitive nature of these crimes. There is evidence that
bias in estimating the crime rates from survey data may arise because some
women respondents are "gagged" in reporting some types of crimes by the use of
a telephone rather than a personal interview, and by the presence of a spouse
during the interview. On the other hand, as data on these crimes are collected
every year, it would be more efficient in data analysis if we could identify
and make use of information from previous data. In this paper we propose a
model to adjust the estimates of the rates of rape and domestic violence to
account for the response bias due to the "gag" factors. To estimate parameters
in the model, we identify the information that is not sensitive to time and
incorporate this into prior distributions. The strength of Bayesian estimators
is their ability to combine information from long observational records in a
sensible way. Within a Bayesian framework, we develop an
Expectation-Maximization-Bayesian (EMB) algorithm for computation in analyzing
contingency table and we apply the jackknife to estimate the accuracy of the
estimates. Our approach is illustrated using the yearly crime data from the
National Crime Victimization Survey. The illustration shows that compared with
the classical method, our model leads to more efficient estimation but does not
require more complicated computation.


title:
Non-monotonic swelling of a macroion due to correlation-induced charge
  inversion

abstract:
  It is known that a large, charged body immersed in a solution of multivalent
counterions may undergo charge inversion as the counterions adsorb to its
surface. We use the theory of charge inversion to examine the case of a
deformable, porous macroion which may adsorb multivalent ions into its bulk to
form a three-dimensional strongly-correlated liquid. This adsorption may lead
to non-monotonic changes in the size of the macroion as multivalent ions are
added to the solution. The macroion first shrinks as its bare charge is
screened and then reswells as the adsorbed ions invert the sign of the net
charge. We derive a value for the outward pressure experienced by such a
macroion as a function of the ion concentration in solution. We find that for
small deviations in the concentration of multivalent ions away from the neutral
point (where the net charge of the body is zero), the swollen size grows
parabolically with the logarithm of the ratio of multivalent ion concentration
to the concentration at the neutral point.


title:
Quenched convergence of a sequence of superprocesses in R^d among
  Poissonian obstacles

abstract:
  We prove a convergence theorem for a sequence of super-Brownian motions
moving among hard Poissonian obstacles, when the intensity of the obstacles
grows to infinity but their diameters shrink to zero in an appropriate manner.
The superprocesses are shown to converge in probability for the law
$\mathbf{P}$ of the obstacles, and $\mathbf{P}$-almost surely for a
subsequence, towards a superprocess with underlying spatial motion given by
Brownian motion and (inhomogeneous) branching mechanism $\psi(u,x)$ of the form
$\psi(u,x)= u^2+ \kappa(x)u$, where $\kappa(x)$ depends on the density of the
obstacles. This work draws on similar questions for a single Brownian motion.
In the course of the proof, we establish precise estimates for integrals of
functions over the Wiener sausage, which are of independent interest.


title: New approach to the thermal Casimir force between real metals

abstract:
  The new approach to the theoretical description of the thermal Casimir force
between real metals is presented. It uses the plasma-like dielectric
permittivity that takes into account the interband transitions of core
electrons. This permittivity precisely satisfies the Kramers-Kronig relations.
The respective Casimir entropy is positive and vanishes at zero temperature in
accordance with the Nernst heat theorem. The physical reasons why the Drude
dielectric function, when substituted in the Lifshitz formula, is inconsistent
with electrodynamics are elucidated. The proposed approach is the single one
consistent with all measurements of the Casimir force performed up to date. The
application of this approach to metal-type semiconductors is considered.


title: A Characteristic Map for Symplectic Manifolds

abstract:
  We construct a local characteristic map to a symplectic manifold M via
certain cohomology groups of Hamiltonian vector fields. For each p in M, the
Leibniz cohomology of the Hamiltonian vector fields on R^{2n} maps to the
Leibniz cohomology of all Hamiltonian vector fields on M. For a particular
extension g_n of the symplectic Lie algebra, the Leibniz cohomology of g_n is
shown to be an exterior algebra on the canonical symplectic two-form. The
Leibniz homology of g_n then maps to the Leibniz homology of Hamiltonian vector
fields on R^{2n}.


title: Scalar Nature of the Nuclear Density Functional

abstract:
  Because of the rotational invariance of the nuclear Hamiltonian, there exists
a density functional for nuclei that depends only on two scalar densities.
Practical calculations boil down to radial, one-dimensional ones.


title: Lattice Dynamics and Thermal Equation of State of Platinum

abstract:
  Platinum is widely used as a pressure calibration standard. However, the
established thermal EOS has uncertainties, especially in the high $P$-$T$
range. We use density functional theory to calculate the thermal equation of
state of platinum, up to 550 GPa and 5000 K. The static lattice energy is
computed by using the LAPW method, with LDA, PBE, and the recently proposed WC
functional. The electronic thermal free energy is evaluated using the Mermin
functional. The vibrational part is computed within the quasi-harmonic
approximation using density functional perturbation theory and
pseudopotentials. Special attention is paid to the influence of the electronic
temperature to the phonon frequencies. We find that in overall LDA results
agree best with the experiments. Based on the DFT calculations and the
established experimental data, we develop a consistent thermal EOS of platinum
as a reference for pressure calibration.


title:
A linear path toward synchronization: Anomalous scaling in a new class
  of exactly solvable Kuramoto models

abstract:
  Using a recently introduced linear reformulation of the Kuramoto model of
self-synchronizing oscillator systems (arXiv:0704.1166), we study a new class
of analytically solvable oscillator systems defined by a particular coupling
scheme. We show that these systems have a logarithimic scaling law in the
vicinity of the critical point, which may be seen as anomalous with respect to
the usual power-law behavior exhibited by the standard Kuramoto model.


title: Brane assisted quintessential inflation with transient acceleration

abstract:
  A simple model of quintessential inflation with the modified exponential
potential exp(-\alpha \phi) [A + (\phi-\phi_0)^2] is analyzed in the braneworld
context. Considering reheating via instant preheating, it is shown that the
evolution of the scalar field \phi from inflation to the present epoch is
consistent with the observational constraints in a wide region of the parameter
space. The model exhibits transient acceleration at late times for 0.96 < A
\alpha^2 < 1.26 and 271 < \phi_0 \alpha < 273, while permanent acceleration is
obtained for 2.3 10^{-8} < A \alpha^2 < 0.98 and 255 < \phi_0 \alpha < 273. The
steep parameter \alpha is constrained to be in the range 5.3 < \alpha < 10.8.


title:
Current-sheet Evolution near a Hyperbolic Magnetic Neutral Line in Hall
  Magnetohydrodynamics: An Exact Solution

abstract:
  \large{\bf Abstract-} Unsteady Hall Magnetohydrodynamics (MHD) near a
hyperbolic magnetic neutral line is investigated. An exact analytical solution
describing a self-similar evolution is given. This solution shows a negligible
impact on the current-sheet formation process near the hyperbolic magnetic
neutral line at small times by the Hall effect but, subsequently, a quenching
by the Hall effect of the finite-time singularity exhibited in ideal MHD and,
hence a prevention of the current density blow-up at large times. The
asymptotic result given by this time-dependent solution is in full quantitative
agreement with the formulation of \textit{steady} Hall MHD near a $X$-type
magnetic neutral line (Shivamoggi [23]). The latter formulation showed that
this asymptotic result indeed corresponds to a hyperbolic configuration of the
magnetic field lines in the \textit{steady} case.


title: Harish-Chandra integrals as nilpotent integrals

abstract:
  Recently the correlation functions of the so-called
Itzykson-Zuber/Harish-Chandra integrals were computed (by one of the authors
and collaborators) for all classical groups using an integration formula that
relates integrals over compact groups with respect to the Haar measure and
Gaussian integrals over a maximal nilpotent Lie subalgebra of their
complexification. Since the integration formula a posteriori had the same form
for the classical series, a conjecture was formulated that such a formula
should hold for arbitrary semisimple Lie groups. We prove this conjecture using
an abstract Lie-theoretic approach.


title: Hall Resistive Tearing Mode: A Variational Formulation

abstract:
  A unified linear tearing-mode formulation is given incorporating both
resistivity and Hall effects. A variational method is used that appears to be
best suited to deal with the difficulties peculiar to the {\it triple-deck}
structure associated with the Hall resistive tearing mode but also to lead to a
convenient analytical dispersion relation for the Hall resisitive tearing mode.
  This analytical dispersion relation -
  * recovers the Furth-Killeen-Rosenbluth[15] result for the resistive branch;
  * gives a growth rate for the Hall branch which appears to be consistent with
the growth rate of the electron-inertia driven tearing mode given previously
(Coppi [19]);
  * recovers the scaling relation for the transition from the resisitive regime
to the Hall regime numerically established by Fitzpatrick[20] in a driven Hall
resistive reconnection situation.


title:
Exact results and new insights for models defined over small-world
  networks. First and second order phase transitions. I: General result

abstract:
  We present, as a very general method, an effective field theory to analyze
models defined over small-world networks. Even if the exactness of the method
is limited to the paramagnetic regions and to some special limits, it gives the
exact critical behavior and the exact critical surfaces and percolation
thresholds, and provide a clear and immediate (also in terms of calculation)
insight of the physics. The underlying structure of the non random part of the
model, i.e., the set of spins staying in a given lattice L_0 of dimension d_0
and interacting through a fixed coupling J_0, is exactly taken into account.
When J_0\geq 0, the small-world effect gives rise to the known fact that a
second order phase transition takes place, independently of the dimension d_0
and of the added random connectivity c. However, when J_0<0, a completely
different scenario emerges where, besides a spin glass transition, multiple
first- and second-order phase transitions may take place.