title: Order and Disorder in AKLT Antiferromagnets in Three Dimensions

abstract:
  The models constructed by Affleck, Kennedy, Lieb, and Tasaki describe a
family of quantum antiferromagnets on arbitrary lattices, where the local spin
S is an integer multiple M of half the lattice coordination number. The equal
time quantum correlations in their ground states may be computed as finite
temperature correlations of a classical O(3) model on the same lattice, where
the temperature is given by T=1/M. In dimensions d=1 and d=2 this mapping
implies that all AKLT states are quantum disordered. We consider AKLT states in
d=3 where the nature of the AKLT states is now a question of detail depending
upon the choice of lattice and spin; for sufficiently large S some form of Neel
order is almost inevitable. On the unfrustrated cubic lattice, we find that all
AKLT states are ordered while for the unfrustrated diamond lattice the minimal
S=2 state is disordered while all other states are ordered. On the frustrated
pyrochlore lattice, we find (conservatively) that several states starting with
the minimal S=3 state are disordered. The disordered AKLT models we report here
are a significant addition to the catalog of magnetic Hamiltonians in d=3 with
ground states known to lack order on account of strong quantum fluctuations.


title:
On the localized phase of a copolymer in an emulsion: subcritical
  percolation regime

abstract:
  The present paper is a continuation of \cite{dHP07b}. The object of interest
is a two-dimensional model of a directed copolymer, consisting of a random
concatenation of hydrophobic and hydrophilic monomers, immersed in an emulsion,
consisting of large blocks of oil and water arranged in a percolation-type
fashion. The copolymer interacts with the emulsion through an interaction
Hamiltonian that favors matches and disfavors mismatches between the monomers
and the solvents, in such a way that the interaction with the oil is stronger
than with the water.
  The model has two regimes, supercritical and subcritical, depending on
whether the oil blocks percolate or not. In \cite{dHP07b} we focussed on the
supercritical regime and obtained a complete description of the phase diagram,
which consists of two phases separated by a single critical curve. In the
present paper we focus on the subcritical regime and show that the phase
diagram consists of four phases separated by three critical curves meeting in
two tricritical points.


title: Fine-Tuning in DBI Inflationary Mechanism

abstract:
  We show a model-independent fine-tuning issue in the DBI inflationary
mechanism. DBI inflation requires a warp factor h small enough to sufficiently
slow down the inflaton. On the other hand, the Einstein equation in extra
dimensions under the inflationary background deforms the warp space in the IR
side. Generically these two locations coincide with each other, spoiling the
DBI inflation. The origin and tuning of this ``h-problem'' is closely related,
through the AdS/CFT duality, to those of the well-known ``eta-problem'' in the
slow-roll inflationary mechanism.


title: Nonlinear Solar Dynamo Model with Magnetic Helicity

abstract:
  Variations of the sunspot number are important indicators of the solar
activity cycles. The sunspot formation is a result of a dynamo process inside
the Sun, which is far from being understood. We use simple dynamical models of
the dynamo process to simulate the magnetic field evolution and investigate
general properties of the sunspot number variations during the solar cycles. We
have found that the classical Parker's model with a standard kinetic helicity
quenching cannot represent the typical profiles of the solar-cycle variations
of the sunspot number, and also does not give chaotic solutions. For modeling
of the solar cycle properties we use a nonlinear dynamo model of Kleeorin and
Ruzmaikin (1982), which takes into account dynamics of the turbulent magnetic
helicity. We have obtained a series of periodic and chaotic solutions for
different layers of the convective zone. The solutions qualitatively reproduce
some basic observational features of the solar cycle properties, in particular,
the relationship between the growth time and the cycle amplitude. Also, on the
longer time scale the dynamo model with the magnetic helicity has intermittent
solutions, which may be important for modeling long-term variations of the
solar cycles.


title:
A model of diffusion in a potential well for the dynamics of the
  large-scale circulation in turbulent Rayleigh-Benard convection

abstract:
  Experimental measurements of properties of the large-scale circulation (LSC)
in turbulent convection of a fluid heated from below in a cylindrical container
of aspect ratio one are presented and used to test a model of diffusion in a
potential well for the LSC. The model consists of a pair of stochastic ordinary
differential equations motivated by the Navier-Stokes equations. The two
coupled equations are for the azimuthal orientation theta_0, and for the
azimuthal temperature amplitude delta at the horizontal midplane. The dynamics
is due to the driving by Gaussian distributed white noise that is introduced to
represent the action of the small-scale turbulent fluctuations on the
large-scale flow. Measurements of the diffusivities that determine the noise
intensities are reported. Two time scales predicted by the model are found to
be within a factor of two or so of corresponding experimental measurements. A
scaling relationship predicted by the model between delta and the Reynolds
number is confirmed by measurements over a large experimental parameter range.
The Gaussian peaks of probability distributions p(delta) and p(\dot\theta_0)
are accurately described by the model; however the non-Gaussian tails of
p(delta) are not. The frequency, angular change, and amplitude bahavior during
cessations are accurately described by the model when the tails of the
probability distribution of $\delta$ are used as experimental input.


title: Luminescence Spectra of Quantum Dots in Microcavities. I. Bosons

abstract:
  We provide a unified theory of luminescence spectra of coupled light-matter
systems realized with semiconductor heterostructures in microcavities,
encompassing: i) the spontaneous emission case, where the system decays from a
prepared (typically pure) initial state, and ii) luminescence in the presence
of a continuous, incoherent pump. While the former case has been amply
discussed in the literature (albeit mainly for the case of resonance), no
consideration has been given to the influence of the incoherent pump. We show
how, by provoking a self-consistent quantum state, the pump considerably alters
the emission spectra, even at vanishing intensities. The main outcome of our
analysis is to unambiguously identify strong-coupling in situations where it
appears in disguise or only seems to appear. Here, we consider bosonic matter
fields, in which case fully analytical solutions can be obtained. This
describes the case of quantum wells or large quantum dots, or the limit of low
excitation where the average populations remain much smaller than one.


title: Status of the Hadronic Tau Determination of V_us

abstract:
  We update the extraction of |V_{us}| from hadronic tau decay data in light of
recent BaBar and Belle results on the branching fractions of a number of
important strange decay modes. A range of sum rule analyses is performed,
particular attention being paid to those based on "non-spectral weights",
developed previously to bring the slow convergence of the relevant integrated
D=2 OPE series under improved control. Results from the various sum rules are
shown to be in good agreement with one another, but ~3 sigma below expectations
based on 3-family unitarity. Important avenues for future study are briefly
discussed.


title:
Fermionic T-Duality, Dual Superconformal Symmetry, and the
  Amplitude/Wilson Loop Connection

abstract:
  We show that tree level superstring theories on certain supersymmetric
backgrounds admit a symmetry which we call ``fermionic T-duality''. This is a
non-local redefinition of the fermionic worldsheet fields similar to the
redefinition we perform on bosonic variables when we do an ordinary T-duality.
This duality maps a supersymmetric background to another supersymmetric
background with different RR fields and a different dilaton. We show that a
certain combination of bosonic and fermionic T-dualities maps the full
superstring theory on $AdS_5 \times S^5$ back to itself in such a way that
gluon scattering amplitudes in the original theory map to something very close
to Wilson loops in the dual theory. This duality maps the ``dual superconformal
symmetry'' of the original theory to the ordinary superconformal symmetry of
the dual model. This explains the dual superconformal invariance of planar
scattering amplitudes of N=4 super Yang Mills and also sheds some light on the
connection between amplitudes and Wilson loops. In the appendix, we propose a
simple prescription for open superstring MHV tree amplitudes in a flat
background.


title: Quantum Inverse Scattering Method with anyonic grading

abstract:
  We formulate the Quantum Inverse Scattering Method for the case of anyonic
grading. This provides a general framework for constructing integrable models
describing interacting hard-core anyons. Through this method we reconstruct the
known integrable model of hard core anyons associated with the XXX model, and
as a new application we construct the anyonic $t-J$ model. The energy spectrum
for each model is derived by means of a generalisation of the algebraic Bethe
ansatz. The grading parameters implementing the anyonic signature give rise to
sector-dependent phase factors in the Bethe ansatz equations.


title:
On algebras admitting a complete set of near weights, evaluation codes
  and Goppa codes

abstract:
  In 1998 Hoholdt, van Lint and Pellikaan introduced the concept of a ``weight
function'' defined on a F_q-algebra and used it to construct linear codes,
obtaining among them the algebraic-geometric (AG) codes supported on one point.
Later it was proved by Matsumoto that all codes produced using a weight
function are actually AG codes supported on one point. Recently, ``near weight
functions'' (a generalization of weight functions), also defined on a
F_q-algebra, were introduced to study codes supported on two points. In this
paper we show that an algebra admits a set of m near weight functions having a
compatibility property, namely, the set is a ``complete set'', if and only if
it is the ring of regular functions of an affine geometrically irreducible
algebraic curve defined over F_q whose points at infinity have a total of m
rational branches. Then the codes produced using the near weight functions are
exactly the AG codes supported on m points. A formula for the minimum distance
of these codes is presented with examples which show that in some situations it
compares better than the usual Goppa bound.


title:
Optical spectra of a quantum dot in a microcavity in the nonlinear
  regime

abstract:
  The optical emission spectrum of a quantum dot in strong coupling with the
single mode of a microcavity is obtained in the nonlinear regime. We study how
exciton-exciton interactions alter the emission spectrum of the system,
bringing the linear Rabi doublet into a multiplet structure that is strongly
dependent on the cavity-exciton energy detuning. We emphasise how nonlinearity
can be used to evidence the genuine quantum nature of the coupling by producing
satellites peaks of the Rabi doublet that originate from the quantized energy
levels of the interactions.


title: Squeezed single-atom laser in a photonic crystal

abstract:
  We study non-classical and spectral properties of a strongly driven
single-atom laser engineered within a photonic crystal that facilitates a
frequency-dependent reservoir. In these studies, we apply a dressed atom model
approach to derive the master equation of the system and study the properties
of the dressed laser under the frequency dependent transition rates. By going
beyond the secular approximation in the dressed-atom cavity field interaction,
we find that if, in addition, the non-secular terms are included into the
dynamics of the system, then non-linear processes can occur that lead to
interesting new aspects of cavity field behavior. We calculate variances of the
quadrature phase amplitudes and the incoherent part of the spectrum of the
cavity field and show that they differ qualitatively from those observed under
the secular approximation. In particular, it is found that the non-linear
processes lead to squeezing of the fluctuations of the cavity field below the
quantum shot noise limit. The squeezing depends on the relative population of
the dressed states of the system and is found only if there is no population
inversion between the dressed states. Furthermore, we find a linewidth
narrowing below the quantum limit in the spectrum of the cavity field that is
achieved only when the secular approximation is not made. An interpretation of
the linewidth narrowing is provided in terms of two phase dependent noise
(squeezing) spectra that make up the incoherent spectrum. We establish that the
linewidth narrowing is due squeezing of the fluctuations in one quadrature
phase components of the cavity field.


title:
Finite-size-scaling ansatz for the helicity modulus of the
  triangular-lattice three-spin interaction model

abstract:
  The Berezinskii-Kosterlitz-Thouless-type continuous phase transition observed
in the three-spin interaction model is discussed. The relevant field theory
describes the topological defects involved and enables us to perform the
renormalization-group analysis. Based on it, we shall propose the
finite-size-scaling ansatz for the helicity modulus which exhibits the exponent
$\bar\nu=3/5$ for the correlation length in the disordered phase. We perform
the Monte Carlo simulations to confirm the ansatz. Also, we argue its relevance
to the ground-state phase transition in the quantum spin chain.


title: On a conjecture of Ira Gessel

abstract:
  Let F(m; n1, n2) denote the number of lattice walks from (0,0) to (n1,n2),
always staying in the first quadrant {(n_1,n_2); n1 >= 0, n2 >= 0} and having
exactly m steps, each of which belongs to the set {E=(1,0), W=(-1,0), NE=(1,1),
SW=(-1,-1)}. Ira Gessel conjectured that F(2n; 0, 0) = 16^n (1/2)_n (5/6)_n /
((2)_n (5/3)_n) where (a)_n is the Pochhammer symbol. We pose similar
conjectures for some other values of (n1,n2), and give closed-form formulas for
F(n1; n1, n2) when n1 >= n2 as well as for F(2n2 - n1; n1, n2) when n1 <= n2.
In the main part of the paper, we derive a functional equation satisfied by the
generating function of F(m; n1, n2), use the kernel method to turn it into an
infinite lower-triangular system of linear equations satisfied by the values of
F(m; n1, 0) and F(m; 0, n2) + F(m; 0, n2 - 1), and express these values
explicitly as determinants of lower-Hessenberg matrices with unit
superdiagonals whose non-zero entries are products of two binomial
coefficients.


title: Determination of the Neutrino Mass Hierarchy at an Intermediate Baseline

abstract:
  It is generally believed that neutrino mass hierarchy can be determined at a
long baseline experiment, often using accelerator neutrino beams. Reactor
neutrino experiments at an intermediate baseline have the capability to
distinguish normal or inverted hierarchy. Recently it has been demonstrated
that the mass hierarchy could possibly be identified using Fourier transform to
the L/E spectrum if the mixing angle $\sin^2(2\theta_{13})>0.02$. In this study
a more sensitive Fourier analysis is introduced. We found that an ideal
detector at an intermediate baseline ($\sim 60$ km) could identify the mass
hierarchy for a mixing angle $\sin^2(2\theta_{13}) > 0.005$, without
requirements on accurate information of reactor neutrino spectra and the value
of $\Delta m^2_{32}$.


title: Practical Coherent Integration with the NPOI

abstract:
  In this paper we will discuss the current status of coherent integration with
the Navy Prototype Optical Interferometer (NPOI) (Armstrong et al. 2008).
Coherent integration relies on being able to phase reference interferometric
measurements, which in turn relies on making measurements at multiple
wavelengths. We first discuss the generalized group-delay approach, then the
meaning of the resulting complex visibilities and then demonstrate how coherent
integration can be used to perform very precision measurement of stellar
properties. For example, we demonstrate how we can measure the diameter of a
star to a precision of one part in 350, and measure properties of binary stars.
The complex phase is particularly attractive as a data product because it is
not biased in the same way as visibility amplitudes.


title:
Vibrational dynamics of 3D granular media composed with polyhedral
  grains -- Din\'amica vibracional de un medio granular 3D compuesto de
  part\'iculas poli\'edricas

abstract:
  By means of tree-dimensional contact dynamics simulations, we analyze the
vibrational dynamics of a confined granular layer in response to harmonic
forcing. The sample is composed of polyedric grains with a shape derived from
digitalized ballast. The system involves a jammed state separating passive
(loading) and active (unloading) states. We show that an approximate expression
of the packing resistance force as a function of the displacement of the free
retaining wall from the jamming position provides a good description of the
dynamics. We study in detail the scaling of displacements and velocities with
loading parameters. In particular, we find that, for a wide range of
frequencies, the data collapse by scaling the displacements with the inverse
square of frequency, the inverse of the force amplitude and the square of
gravity. We show that the mean compaction rate increases linearly with
frequency up to a characteristic frequency of 10 Hz and then it declines in
inverse proportion to frequency.


title: Measurements of binary stars with coherent integration of NPOI data

abstract:
  In this paper we use coherently integrated visibilities (see separate paper
in these proceedings, Jorgensen et al. 2008) to measure the properties of
binary stars. We use only the phase of the complex visibility and not the
amplitude. The reason for this is that amplitudes suffer from the calibration
effect (the same for coherent and incoherent averages) and thus effectively
provide lower accuracy measurements. We demonstrate that the baseline phase
alone can be used to measure the separation, orientation and brightness ratio
of a binary star, as a function of wavelength.


title:
Boundary conditions for coupled quasilinear wave equations with
  application to isolated systems

abstract:
  We consider the initial-boundary value problem for systems of quasilinear
wave equations on domains of the form $[0,T] \times \Sigma$, where $\Sigma$ is
a compact manifold with smooth boundaries $\partial\Sigma$. By using an
appropriate reduction to a first order symmetric hyperbolic system with maximal
dissipative boundary conditions, well posedness of such problems is established
for a large class of boundary conditions on $\partial\Sigma$. We show that our
class of boundary conditions is sufficiently general to allow for a well posed
formulation for different wave problems in the presence of constraints and
artificial, nonreflecting boundaries, including Maxwell's equations in the
Lorentz gauge and Einstein's gravitational equations in harmonic coordinates.
Our results should also be useful for obtaining stable finite-difference
discretizations for such problems.


title:
Sudden death, birth and stable entanglement in a two-qubit Heisenberg XY
  spin chain

abstract:
  Taking the decoherence effect due to population relaxation into account, we
investigate the entanglement properties for two qubits in the Heisenberg XY
interaction and subject to an external magnetic field. It is found that the
phenomenon of entanglement sudden death (ESD) as well as sudden birth(ESB)
appear during the evolution process for particular initial states. The
influence of the external magnetic field and the spin environment on ESD and
ESB are addressed in detail. It is shown that the concurrence, a measure of
entanglement, can be controlled by tuning the parameters of the spin chain,
such as the anisotropic parameter, external magnetic field, and the coupling
strength with their environment. In particular, we find that a critical
anisotropy constant exists, above which ESB vanishes while ESD appears. It is
also notable that stable entanglement, which is independent of different
initial states of the qubits, occurs even in the presence of decoherence.


title:
Bayes-optimal inverse halftoning and statistical mechanics of the
  Q-Ising model

abstract:
  On the basis of statistical mechanics of the Q-Ising model, we formulate the
Bayesian inference to the problem of inverse halftoning, which is the inverse
process of representing gray-scales in images by means of black and white dots.
Using Monte Carlo simulations, we investigate statistical properties of the
inverse process, especially, we reveal the condition of the Bayes-optimal
solution for which the mean-square error takes its minimum. The numerical
result is qualitatively confirmed by analysis of the infinite-range model. As
demonstrations of our approach, we apply the method to retrieve a grayscale
image, such as standard image `Lenna', from the halftoned version. We find that
the Bayes-optimal solution gives a fine restored grayscale image which is very
close to the original.


title: Concentration of maps and group action

abstract:
  In this paper, from the viewpoint of the concentration theory of maps, we
study a compact group and a L\'{e}vy group action to a large class of metric
spaces, such as R-trees, doubling spaces, metric graphs, and Hadamard
manifolds.


title:
Thickness Estimation of Epitaxial Graphene on SiC using Attenuation of
  Substrate Raman Intensity

abstract:
  A simple, non-invasive method using Raman spectroscopy for the estimation of
the thickness of graphene layers grown epitaxially on silicon carbide (SiC) is
presented, enabling simultaneous determination of thickness, grain size and
disorder using the spectra. The attenuation of the substrate Raman signal due
to the graphene overlayer is found to be dependent on the graphene film
thickness deduced from X-ray photoelectron spectroscopy and transmission
electron microscopy of the surfaces. We explain this dependence using an
absorbing overlayer model. This method can be used for mapping graphene
thickness over a region and is capable of estimating thickness of multilayer
graphene films beyond that possible by XPS and Auger electron spectroscopy
(AES).


title:
Construction of Large Constant Dimension Codes With a Prescribed Minimum
  Distance

abstract:
  In this paper we construct constant dimension space codes with prescribed
minimum distance. There is an increased interest in space codes since a paper
by Koetter and Kschischang were they gave an application in network coding.
There is also a connection to the theory of designs over finite fields. We will
modify a method of Braun, Kerber and Laue which they used for the construction
of designs over finite fields to do the construction of space codes. Using this
approach we found many new constant dimension spaces codes with a larger number
of codewords than previously known codes. We will finally give a table of the
best found constant dimension space codes.


title: Optimal quantum estimation in spin systems at criticality

abstract:
  It is a general fact that the coupling constant of an interacting many-body
Hamiltonian do not correspond to any observable and one has to infer its value
by an indirect measurement. For this purpose, quantum systems at criticality
can be considered as a resource to improve the ultimate quantum limits to
precision of the estimation procedure. In this paper, we consider the
one-dimensional quantum Ising model as a paradigmatic example of many-body
system exhibiting criticality, and derive the optimal quantum estimator of the
coupling constant varying size and temperature. We find the optimal external
field, which maximizes the quantum Fisher information of the coupling constant,
both for few spins and in the thermodynamic limit, and show that at the
critical point a precision improvement of order $L$ is achieved. We also show
that the measurement of the total magnetization provides optimal estimation for
couplings larger than a threshold value, which itself decreases with
temperature.


title: Two-electron bound states in continuum in quantum dots

abstract:
  Bound state in continuum (BIC) might appear in open quantum dots for
variation of the dot's shape. By means of the equations of motion of Green
functions we investigate effect of strong intradot Coulomb interactions on that
phenomenon in the framework of impurity Anderson model. Equation that imaginary
part of poles of the Green function equals to zero gives condition for BICs. As
a result we show that Coulomb interactions replicate the single-electron BICs
into two-electron ones.


title:
Development of a Classical Force Field for the Oxidised Si Surface:
  Application to Hydrophilic Wafer Bonding

abstract:
  We have developed a classical two- and three-body interaction potential to
simulate the hydroxylated, natively oxidised Si surface in contact with water
solutions, based on the combination and extension of the Stillinger-Weber
potential and of a potential originally developed to simulate SiO2 polymorphs.
The potential parameters are chosen to reproduce the structure, charge
distribution, tensile surface stress and interactions with single water
molecules of a natively oxidised Si surface model previously obtained by means
of accurate density functional theory simulations. We have applied the
potential to the case of hydrophilic silicon wafer bonding at room temperature,
revealing maximum room temperature work of adhesion values for natively
oxidised and amorphous silica surfaces of 97 mJ/m2 and 90mJ/m2, respectively,
at a water adsorption coverage of approximately 1 monolayer. The difference
arises from the stronger interaction of the natively oxidised surface with
liquid water, resulting in a higher heat of immersion (203 mJ/m2 vs. 166
mJ/m2), and may be explained in terms of the more pronounced water structuring
close to the surface in alternating layers of larger and smaller density with
respect to the liquid bulk. The computed force-displacement bonding curves may
be a useful input for cohesive zone models where both the topographic details
of the surfaces and the dependence of the attractive force on the initial
surface separation and wetting can be taken into account.


title: The Overshoot Problem and Giant Structures

abstract:
  Models of small-field inflation often suffer from the overshoot problem. A
particularly efficient resolution to the problem was proposed recently in the
context of string theory. We show that this resolution predicts the existence
of giant spherically symmetric overdense regions with radius of at least 110
Mpc. We argue that if such structures will be found they could offer an
experimental window into string theory.


title: New Narrow Nucleon N*(1685)

abstract:
  We argue that the existence of a new narrow (Gamma < 25 MeV) nucleon
resonance N*(1685) is strongly supported by recent data on eta photoproduction
off the nucleon. The resonance has much stronger photo-coupling to the neutron
than to the proton. This nucleon resonance is a good candidate for the
non-strange member of the exotic anti-decouplet of baryons -- the partner of
the pentaquark Theta+. All up to date known properties of new N*(1685) are
summarized.


title:
Coulomb energy contribution to the excitation energy in $^{229}$Th and
  enhanced effect of $\alpha$ variation

abstract:
  We calculated the contribution of Coulomb energy to the spacing between the
ground and first excited state of $^{229}$Th nucleus as a function of the
deformation parameter $\delta$. We show that despite the fact that the odd
particle is a neutron, the change in Coulomb energy between these two states
can reach several hundreds KeV.This means that the effect of the variation of
the fine structure constant $\alpha=e^2/\hbar c$ may be enhanced
  $\Delta U_C/E \sim 10^4$ times in the $E=$7.6 eV "nuclear clock" transition
between the ground and first excited states in the $^{229}$Th nucleus.


title: Amplitude variability and multiple frequencies in 44 Tau: 2000 - 2006

abstract:
  This study has three principal aims: (i) to increase the number of detected
pulsation modes of 44 Tau, especially outside the previously known frequency
ranges, (ii) to study the amplitude variability and its systematics, and (iii)
to examine the combination frequencies.
  During the 2004/5 and 2005/6 observing seasons, high-precision photometry was
obtained with the Vienna Automatic Photoelectric Telescope in Arizona during 52
nights. Together with previous campaigns, a data base from 2000 to 2006 was
available for multifrequency analyses.
  Forty-nine pulsation frequencies are detected, of which 15 are independent
pulsation modes and 34 combination frequencies or harmonics. The newly found
gravity mode at 5.30 c/d extends the known frequency range of instability.
Strong amplitude variability from year to year is found for the \ell = 1 modes,
while the two radial modes have essentially constant amplitudes. Possible
origins of the amplitude variability of the \ell = 1 modes, such as precession
of the pulsation axis, beating and resonance effects are considered. The
amplitudes of the combination frequencies, f_i + f_j, mirror the variations in
the parent modes. The combination parameter, which relates the amplitudes of
the combination frequencies to those of the parent modes, is found to be
different for different parents.


title:
Characterisation of a silicon photomultiplier device for applications in
  liquid argon based neutrino physics and dark matter searches

abstract:
  The performance of a silicon photomultiplier has been assessed at low
temperature in order to evaluate its suitability as a scintillation readout
device in liquid argon particle physics detectors. The gain, measured as 2.1E6
for a constant over-voltage of 4V was measured between 25degC and -196degC and
found to be invariant with temperature, the corresponding single photoelectron
dark count rate reducing from 1MHz to 40Hz respectively. Following multiple
thermal cycles no deterioration in the device performance was observed. The
photon detection efficiency (PDE) was assessed as a function of photon
wavelength and temperature. For an over-voltage of 4V, the PDE, found again to
be invariant with temperature, was measured as 25% for 460nm photons and 11%
for 680nm photons. Device saturation due to high photon flux rate, observed
both at room temperature and -196degC, was again found to be independent of
temperature. Although the output signal remained proportional to the input
signal so long as the saturation limit was not exceeded, the photoelectron
pulse resolution and decay time increased slightly at -196degC.


title: Temperature dependence of single-particle properties in nuclear matter

abstract:
  The single-nucleon potential in hot nuclear matter is investigated in the
framework of the Brueckner theory by adopting the realistic Argonne V18 or
Nijmegen 93 two-body nucleon-nucleon interaction supplemented by a microscopic
three-body force. The rearrangement contribution to the single-particle
potential induced by the ground state correlations is calculated in terms of
the hole-line expansion of the mass operator and provides a significant
repulsive contribution in the low-momentum region around and below the Fermi
surface. Increasing temperature leads to a reduction of the effect, while
increasing density makes it become stronger. The three-body force suppresses
somewhat the ground state correlations due to its strong short-range repulsion,
increasing with density. Inclusion of the three-body force contribution results
in a quite different temperature dependence of the single-particle potential at
high enough densities as compared to that adopting the pure two-body force. The
effects of three-body force and ground state correlations on the nucleon
effective mass are also discussed.


title: The two-user Gaussian interference channel: a deterministic view

abstract:
  This paper explores the two-user Gaussian interference channel through the
lens of a natural deterministic channel model. The main result is that the
deterministic channel uniformly approximates the Gaussian channel, the capacity
regions differing by a universal constant. The problem of finding the capacity
of the Gaussian channel to within a constant error is therefore reduced to that
of finding the capacity of the far simpler deterministic channel. Thus, the
paper provides an alternative derivation of the recent constant gap capacity
characterization of Etkin, Tse, and Wang. Additionally, the deterministic model
gives significant insight towards the Gaussian channel.


title: The NAO humanoid: a combination of performance and affordability

abstract:
  This article presents the design of the autonomous humanoid robot called NAO
that is built by the French company Aldebaran-Robotics. With its height of 0.57
m and its weight about 4.5 kg, this innovative robot is lightweight and
compact. It distinguishes itself from its existing Japanese, American, and
other counterparts thanks to its pelvis kinematics design, its proprietary
actuation system based on brush DC motors, its electronic, computer and
distributed software architectures. This robot has been designed to be
affordable without sacrificing quality and performance. It is an open and
easy-to-handle platform where the user can change all the embedded system
software or just add some applications to make the robot adopt specific
behaviours. The robot's head and forearms are modular and can be changed to
promote further evolution. The comprehensive and functional design is one of
the reasons that helped select NAO to replace the AIBO quadrupeds in the 2008
RoboCup standard league.


title:
Observation of long-lived polariton states in semiconductor
  microcavities across the parametric threshold

abstract:
  The excitation spectrum around the pump-only stationary state of a polariton
optical parametric oscillator (OPO) in semiconductor microcavities is
investigated by time-resolved photoluminescence. The response to a weak pulsed
perturbation in the vicinity of the idler mode is directly related to the
lifetime of the elementary excitations. A dramatic increase of the lifetime is
observed for a pump intensity approaching and exceeding the OPO threshold. The
observations can be explained in terms of a critical slowing down of the
dynamics upon approaching the threshold and the following onset of the soft
Goldstone mode.


title: Exploiting Bird Locomotion Kinematics Data for Robotics Modeling

abstract:
  We present here the results of an analysis carried out by biologists and
roboticists with the aim of modeling bird locomotion kinematics for robotics
purposes. The aim was to develop a bio-inspired kinematic model of the bird leg
from biological data. We first acquired and processed kinematic data for
sagittal and top views obtained by X-ray radiography of quails walking. Data
processing involved filtering and specific data reconstruction in three
dimensions, as two-dimensional views cannot be synchronized. We then designed a
robotic model of a bird-like leg based on a kinematic analysis of the
biological data. Angular velocity vectors were calculated to define the number
of degrees of freedom (DOF) at each joint and the orientation of the rotation
axes.


title: On Primordial Density Perturbation and Decaying Speed of Sound

abstract:
  The decaying speed of sound can lead to the emergence of the primordial
density perturbation in any expanding phase, even if the expansion is
decelerated. Recently, some proposals have been given to implement this
mechanism, in which it was found that the primordial spectrum of scalar
perturbation can be scale invariant. In this note, we will give more insights
for the details of this seeding mechanism.


title:
Quantum decoherence of interacting electrons in arrays of quantum dots
  and diffusive conductors

abstract:
  We develop a new unified theoretical approach enabling us to
non-perturbatively study the effect of electron-electron interactions on weak
localization in arbitrary arrays of quantum dots. Our model embraces (i) weakly
disordered conductors (ii) strongly disordered conductors and (iii) metallic
quantum dots. In all these cases at $T \to 0$ the electron decoherence time is
determined by the universal formula $\tau_{\varphi 0}\sim g\tau_D/\ln
(E_C/\delta)$, where $g$, $\tau_D$, $E_C$ and $\delta$ are respectively
dimensionless conductance, dwell time, charging energy and level spacing of a
single dot. In the case (i) this formula yields $\tau_{\varphi 0}\propto
D^3/\ln D$ ($D$ is the diffusion coefficient) and matches with our previous
quasiclassical results [D.S. Golubev, A.D. Zaikin, Phys. Rev. Lett. 81 (1998)
1074], while in the cases (ii) and (iii) it illustrates new physics not
explored earlier. A detailed comparison between our theory and numerous
experiments provides an overwhelming evidence that zero temperature electron
decoherence in disordered conductors is universally caused by electron-electron
interactions rather than by magnetic impurities.


title: Dual Superconformal Symmetry from AdS5 x S5 Superstring Integrability

abstract:
  We discuss 2d duality transformations in the classical AdS5 x S5 superstring
and their effect on the integrable structure. T-duality along four directions
in Poincare parametrization of AdS5 maps the bosonic part of the superstring
action into itself. On bosonic level, this duality may be understood as a
symmetry of the first-order (phase space) system of equations for the coset
components of the current. The associated Lax connection is invariant modulo
the action of an so(2,4)-automorphism. We then show that this symmetry extends
to the full superstring, provided one supplements the transformation of the
bosonic components of the current with a transformation on the fermionic ones.
At the level of the action, this symmetry can be seen by combining the bosonic
duality transformation with a similar one applied to part of the fermionic
superstring coordinates. As a result, the full superstring action is mapped
into itself, albeit in a different kappa-symmetry gauge. One implication is
that the dual model has the same superconformal symmetry group as the original
one, and this may be seen as a consequence of the integrability of the
superstring. The invariance of the Lax connection under the duality implies a
map on the full set of conserved charges that should interchange some of the
Noether (local) charges with hidden (non-local) ones and vice versa.


title:
Testing adiabatic expansion of shocks in parsec-scale jets by
  dual-frequency VLBI experiments

abstract:
  We present results of simultaneous dual-frequency (2 GHz and 8 GHz) very long
baseline interferometry (VLBI) observations of 12 active galactic nuclei with
prominent jets. Spectral properties of the jets and evolution of their
brightness temperature are discussed. Measured sizes and brightness
temperatures of VLBI features are found to be consistent with emission from
relativistic shocks dominated by adiabatic losses. Physical scenarios with
different magnetic field orientation in the jets are discussed.


title:
Preparation and characterization of an anionic dye-polycation molecular
  films by electrostatic Layer-by-Layer adsorption process

abstract:
  This communication reports the formation and characterization of self
assembled films of a low molecular weight anionic dye amaranth and polycation
Poly (allylamine hydrochloride) (PAH) by electrostatic alternating
Layer-by-Layer (LBL) adsorption. It was observed that there was almost no
material loss occurred during adsorption process. The UV-Vis absorption and
fluorescence spectra of amaranth solution reveal that with the increase in
amaranth concentration in solution, the aggregated species starts to dominate
over the monomeric species. New aggregated band at 600 nm was observed in
amaranth-PAH mixture solution absorption spectrum. A new broad low intense band
at the longer wavelength region, in the amaranth-PAH mixture solution
fluorescence spectrum was observed due to the closer association of amaranth
molecule while tagged into the polymer backbone of PAH and consequent formation
of aggregates. The broad band system in the 650-750 nm region in the
fluorescence spectra of different layered LBL films changes in intensity
distribution among various bands within itself, with changing layer number and
at 10 bilayer LBL films the longer wavelength band at 710 nm becomes prominent.
Existence of dimeric or higher order n-meric species in the LBL films was
confirmed by excitation spectroscopic studies. Almost 45 minute was required to
complete the interaction between amaranth and PAH molecules in the 1-bilayer
LBL film.


title:
BFKL resummation effects in the gamma* gamma* total hadronic cross
  section

abstract:
  We study in the BFKL approach the total hadronic cross section for the
collision of two virtual photons for energies in the range of LEP2 and in the
range of future linear colliders. The BFKL resummation is done at the
next-to-leading order in the BFKL Green's function; photon impact factors are
taken instead at the leading order, but with the inclusion of the subleading
terms required by invariance under changes of the renormalization scale and of
the BFKL scale s_0. We compare our results with previous estimates based on a
similar kind of approximation.


title: Brill-Noether theory for moduli spaces of sheaves on algebraic varieties

abstract:
  Let $X$ be a smooth projective variety of dimension $n$ and let $H$ be an
ample line bundle on $X$. Let $M_{X,H}(r;c_1, ..., c_{s})$ be the moduli space
of $H$-stable vector bundles $E$ on $X$ of rank $r$ and Chern classes
$c_i(E)=c_i$ for $i=1, ..., s:=min\{r,n\}$. We define the Brill-Noether
filtration on $M_{X,H}(r;c_1, ..., c_{s})$ as $W_{H}^{k}(r;c_1,..., c_{s})= \{E
\in M_{X,H}(r;c_1, ..., c_{s}) | h^0(X,E) \geq k \}$ and we realize
$W_{H}^{k}(r;c_1,..., c_{s})$ as the $k$th determinantal variety of a morphism
of vector bundles on $M_{X,H}(r;c_1, ..., c_{s})$, provided $H^i(E)=0$ for $i
\geq 2$ and $E \in M_{X,H}(r;c_1, ..., c_{s})$. We also compute the expected
dimension of $W_{H}^{k}(r;c_1,..., c_{s})$. Very surprisingly we will see that
the Brill-Noether stratification allow us to compare moduli spaces of vector
bundles on Hirzebruch surfaces stables with respect to different polarizations.
We will also study the Brill-Noether loci of the moduli space of instanton
bundles and we will see that they have the expected dimension.


title: List Colouring Squares of Planar Graphs

abstract:
  In 1977, Wegner conjectured that the chromatic number of the square of every
planar graph $G$ with maximum degree $\Delta\ge8$ is at most
$\bigl\lfloor\frac32\Delta\bigr\rfloor+1$. We show that it is at most $\frac32
\Delta (1+o(1))$ (where the $o(1)$ is as $\Delta\to+\infty$), and indeed that
this is true for the list chromatic number and for more general classes of
graphs.


title: Singularities in Speckled Speckle: Screening

abstract:
  We study screening of optical singularities in random optical fields with two
widely different length scales. We call the speckle patterns generated by such
fields speckled speckle, because the major speckle spots in the pattern are
themselves highly speckled. We study combinations of fields whose components
exhibit short- and long-range correlations, and find unusual forms of
screening.


title: A Connection on Manifolds with a Nilpotent Structure

abstract:
  All the connections, pure toward the nilpotent structure, are found. Examples
of manifolds, for which the curvature tensor is pure or hybrid, are given. For
a manifold of B-type a necessary and sufficient condition for purity of the
curvature tensor is proved. It is verified that the conformal change of the
metric of a B-manifold does not retain its purity.


title: Melting a stretched DNA

abstract:
  We study the melting of a double stranded DNA in the presence of stretching
forces, via 3D Monte-Carlo simulations, exactly solvable models and heuristic
arguments. The resulting force-temperature phase diagram is dramatically
different for the cases where the force is applied to only one strand or to
both. Different assumptions on the monomer size of single and double stranded
DNA lead to opposite conclusions as to whether DNA melts or not as it
overstretches.


title: Mapping the galactic gravitational potential with peculiar acceleration

abstract:
  It has been suggested recently that the change in cosmological redshift (the
Sandage test of expansion) could be observed in the next generation of large
telescopes and ultra-stable spectrographs. In a recent paper we estimated the
change of peculiar velocity, i.e. the peculiar acceleration, in nearby galaxies
and clusters and shown it to be of the same order of magnitude as the typical
cosmological signal. Mapping the acceleration field allows for a reconstruction
of the galactic gravitational potential without assuming virialization. In this
paper we focus on the peculiar acceleration in our own Galaxy, modeled as a
Kuzmin disc and a dark matter spherical halo. We estimate the peculiar
acceleration for all known Galactic globular clusters and find some cases with
an expected velocity shift in excess of 20 cm/sec for observations fifteen
years apart, well above the typical cosmological acceleration. We then compare
the predicted signal for a MOND (modified Newtonian dynamics) model in which
the spherical dark matter halo is absent. We find that the signal pattern is
qualitatively different, showing that the peculiar acceleration field could be
employed to test competing theories of gravity. However the difference seems
too small to be detectable in the near future.


title: Extracting synaptic conductances from single membrane potential traces

abstract:
  In awake animals, the activity of the cerebral cortex is highly complex, with
neurons firing irregularly with apparent Poisson statistics. One way to
characterize this complexity is to take advantage of the high interconnectivity
of cerebral cortex and use intracellular recordings of cortical neurons, which
contain information about the activity of thousands of other cortical neurons.
Identifying the membrane potential (Vm) to a stochastic process enables the
extraction of important statistical signatures of this complex synaptic
activity. Typically, one estimates the total synaptic conductances (excitatory
and inhibitory) but this type of estimation requires at least two Vm levels and
therefore cannot be applied to single Vm traces. We propose here a method to
extract excitatory and inhibitory conductances (mean and variance) from single
Vm traces. This "VmT method" estimates conductance parameters using maximum
likelihood criteria, under the assumption are that synaptic conductances are
described by Gaussian stochastic processes and are integrated by a passive
leaky membrane. The method is illustrated using models and is tested on
guinea-pig visual cortex neurons in vitro using dynamic-clamp experiments. The
VmT method holds promises for extracting conductances from single-trial
measurements, which has a high potential for in vivo applications.


title: Mass estimation in the outer non-equilibrium region of galaxy clusters

abstract:
  We discuss a new criterion to estimate the mass in the outer, non-equilibrium
region of galaxy clusters, where the galaxy dynamics is dominated by an overall
infall motion towards the cluster centre. In the framework of the spherical
infall model the local mean velocity of the infalling galaxies at every radius
provides information about the integrated matter overdensity $\delta$. Thus, a
well-defined value of the overdensity $\delta_t$ is expected at the turnaround
radius $r_t$, i.e. the radius where the Hubble flow balances the infall motion.
Within this scenario, we analysed the kinematical properties of a large
catalogue of simulated clusters, using both dark matter particles and member
galaxies as tracer of the infall motion. We also compared the simulation with
analytical calculation performed in the spherical infall approximation, to
analyze the dependence of the results on cosmology in spatially flat universe.
If we normalize cluster mass profiles by means of the turnaround mass $M_t$
(i.e. the mass within $r_t$), they are consistent with an exponential profile
in the whole non-equilibrium region ($0.5\la r/r_t\la 2$). Turnaround radii are
proportional to virialization radii ($r_t\simeq 3.5 r_v$), while turnaround
masses are proportional to virialization masses, i.e. $M_t\simeq 1.7 M_v$,
where $M_v$ is the mass within $r_v$. Actually, the mass evaluated within the
turnaround radius is a more exhaustive evaluation of the total mass of the
cluster. These results can be applied to the analysis of observed clusters.


title: Closed 1-forms in topology and dynamics

abstract:
  This article surveys recent progress of results in topology and dynamics
based on techniques of closed one-forms. Our approach allows us to draw
conclusions about properties of flows by studying homotopical and cohomological
features of manifolds. More specifically we describe a Lusternik - Schnirelmann
type theory for closed one-forms, the focusing effect for flows and the theory
of Lyapunov one-forms. We also discuss recent results about cohomological
treatment of the invariants cat(X, \xi) and cat^1(X, \xi) and their explicit
computation in certain examples.


title: NNLO corrections to 3-jet observables in electron-positron annihilation

abstract:
  I report on a numerical program, which can be used to calculate any infrared
safe three-jet observable in electron-positron annihilation to
next-to-next-to-leading order in the strong coupling constant alpha_s. The
results are compared to a recent calculation by another group. Numerical
differences in three colour factors are discussed and explained.


title:
Delta Self-Consistent Field as a method to obtain potential energy
  surfaces of excited molecules on surfaces

abstract:
  We present a modification of the $\Delta$SCF method of calculating energies
of excited states, in order to make it applicable to resonance calculations of
molecules adsorbed on metal surfaces, where the molecular orbitals are highly
hybridized. The $\Delta$SCF approximation is a density functional method
closely resembling standard density functional theory (DFT), the only
difference being that in $\Delta$SCF one or more electrons are placed in higher
lying Kohn-Sham orbitals, instead of placing all electrons in the lowest
possible orbitals as one does when calculating the ground state energy within
standard DFT. We extend the $\Delta$SCF method by allowing excited electrons to
occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this
extra freedom it is possible to place charge locally on adsorbed molecules in
the calculations, such that resonance energies can be estimated. The method is
applied to N$_2$, CO and NO adsorbed on different metallic surfaces and
compared to ordinary $\Delta$SCF without our modification, spatially
constrained DFT and inverse-photoemission spectroscopy (IPES) measurements.
This comparison shows that the modified $\Delta$SCF method gives results in
close agreement with experiment, significantly closer than the comparable
methods. For N$_2$ adsorbed on ruthenium (0001) we map out a 2-dimensional part
of the potential energy surfaces in the ground state and the 2$\pi$-resonance.
Finally we compare the $\Delta$SCF approach on gas-phase N$_2$ and CO, to
higher accuracy methods. Excitation energies are approximated with accuracy
close to that of time-dependent density functional theory, and we see very good
agreement in the minimum shift of the potential energy surfaces in the excited
state compared to the ground state.


title: Algorithm FIRE -- Feynman Integral REduction

abstract:
  The recently developed algorithm FIRE performs the reduction of Feynman
integrals to master integrals. It is based on a number of strategies, such as
applying the Laporta algorithm, the s-bases algorithm, region-bases and
integrating explicitly over loop momenta when possible. Currently it is being
used in complicated three-loop calculations.


title: Open and Hidden Strangeness Production in Nucleon-Nucleon Collisions

abstract:
  We present an overview of the description of K and eta meson productions in
nucleon-nucleon collisions within an effective Lagrangian model where meson
production proceeds via excitation, propagation and subsequent decay of
intermediate baryonic resonant states. The $K$ meson contains a strange quark
($s$) or antiquark ($\bar s$) while the $\eta$ meson has hidden strangeness as
it contains some component of the $s{\bar s}$ pair. Strange meson production is
expected to provide information on the manifestation of quantum chromodynamics
in the non-perturbative regime of energies larger than that of the low energy
pion physics. We discuss specific examples where proper understanding of the
experimental data for these reactions is still lacking.


title:
Disorder-driven splitting of the conductance peak at the Dirac point in
  graphene

abstract:
  The electronic properties of a bricklayer model, which shares the same
topology as the hexagonal lattice of graphene, are investigated numerically. We
study the influence of random magnetic-field disorder in addition to a strong
perpendicular magnetic field. We found a disorder-driven splitting of the
longitudinal conductance peak within the narrow lowest Landau band near the
Dirac point. The energy splitting follows a relation which is proportional to
the square root of the magnetic field and linear in the disorder strength. We
calculate the scale invariant peaks of the two-terminal conductance and obtain
the critical exponents as well as the multifractal properties of the chiral and
quantum Hall states. We found approximate values $\nu\approx 2.5$ for the
quantum Hall states, but $\nu=0.33\pm 0.1$ for the divergence of the
correlation length of the chiral state at E=0 in the presence of a strong
magnetic field. Within the central $n=0$ Landau band, the multifractal
properties of both the chiral and the split quantum Hall states are the same,
showing a parabolic $f[\alpha(s)]$ distribution with $\alpha(0)=2.27\pm 0.02$.
In the absence of the constant magnetic field, the chiral critical state is
determined by $\alpha(0)=2.14\pm 0.02$.


title: Lower bound on the mass of a black hole

abstract:
  We consider gravity coupled to a massive field whose Compton's wavelength is
far larger than the Planck's length. In the low energy effective action for
gravity, thus, it is the perturbation in the Compton's wavelength that breaks
first as the sub-sub-leading quantum perturbation grows stronger. When this
break occurs, we can not trust the perturbative information about the form of
the low energy effective action. We translate this break into the lowest limit
on the mass of a classical black hole. In D=4, using the electron's mass, this
requires the black hole to be heavier than 10^{14} kg.


title:
A possible mechanism for self coordination of bi-directional traffic
  across nuclear pores

abstract:
  Nuclear pore complexes are constantly confronted by large fluxes of
macromolecules and macromolecular complexes that need to get into and out of
the nucleus. Such bi-directional traffic occurring in a narrow channel can
easily lead to jamming. How then is passage between the nucleus and cytoplasm
maintained under the varying conditions that arise during the lifetime of the
cell? Here, we address this question using computer simulations in which the
behaviour of the ensemble of transporting cargoes is analyzed under different
conditions. We suggest that traffic can exist in two distinct modes, depending
on concentration of cargoes and dissociation rates of the transport
receptor-cargo complexes from the pores. In one mode, which prevails when
dissociation is quick and cargo concentration is low, transport in either
direction proceeds uninterrupted by the other direction. The result is that
overall-traffic-direction fluctuates rapidly and unsystematically between
import and export. Remarkably, when cargo concentrations are high and
dissociation is slow, another mode takes over in which traffic proceeds in one
direction for a certain extent of time, after which it flips direction for
another period. The switch between this, more regulated, mode of transport and
the other, quickly fluctuating state, does not require an active gating
mechanism but rather occurs spontaneously through the dynamics of the
transported particles themselves. The determining factor for the behaviour of
traffic is found to be the exit rate from the pore channel, which is directly
related to the activity of the Ran system that controls the loading and release
of cargo in the appropriate cellular compartment.


title: Non-perturbative QCD Effects and the Top Mass at the Tevatron

abstract:
  The modelling of non-perturbative effects is an important part of modern
collider physics simulations. In hadron collisions there is some indication
that the modelling of the interactions of the beam remnants, the underlying
event, may require non-trivial colour reconnection effects to be present. We
recently introduced a universally applicable toy model of such reconnections,
based on hadronising strings. This model, which has one free parameter, has
been implemented in the Pythia event generator. We then considered several
parameter sets (`tunes'), constrained by fits to Tevatron minimum-bias data,
and determined the sensitivity of a simplified top mass analysis to these
effects, in exclusive semi-leptonic top events at the Tevatron. A first attempt
at isolating the genuine non-perturbative effects gave an estimate of order
+-0.5GeV from non-perturbative uncertainties. The results presented here are an
update to the original study and include recent bug fixes of Pythia that
influenced the tunings investigated.


title: The Emperor's Last Clothes?

abstract:
  We are in the middle of a remarkable paradigm shift in particle physics, a
shift of opinion that occurred so slowly that some even try to deny that they
changed their minds at all. It concerns a very basic question: can we expect to
derive the laws of particle physics from a fundamental theory? The Standard
Model of particle physics as well as the 1984 string theory revolution provided
ample food for thought about this. The reason this was ignored for so long can
be traced back to an old fallacy: a misguided idea about our own importance.


title: A diagrammatic approach to categorification of quantum groups III

abstract: We categorify the idempotented form of quantum sl(n).


title:
Elastic properties of transition metal dioxides: XO$_{2}$(X=Ru, Rh, Os,
  Ir)

abstract:
  The elastic properties of rutile transition metal dioxides XO$_{2}$ (X=Ru,
Rh, Os, and Ir) are investigated using first-principles calculations based on
density functional theory. Elastic constants, bulk modulus, shear modulus, and
Young's modulus as well as Possion ratio are given. OsO$_2$ and IrO$_2$ show
strong incompressibility. The hardness estimated for these dioxides shows that
they are not superhard solids. The obtained Debye temperatures are comparative
to those of transition metal dinitrides or diborides.


title: Physics of collisionless reconnection in a stressed X-point collapse

abstract:
  Recently, magnetic reconnection during collisionless, stressed, X-point
collapse was studied using kinetic, 2.5D, fully electromagnetic, relativistic
Particle-in-Cell numerical code [D. Tsiklauri and T. Haruki, Phys. Plasmas, 14,
112905 (2007)]. Here we finalise the investigation of this topic by addressing
key outstanding physical questions. It has been established here that: (i)
reconnection out-of-plane electric field at the magnetic null is generated by
the electron pressure tensor off-diagonal terms, resembling to the case of
tearing unstable Harris current sheet studied by the GEM reconnection
challenge; (ii) For m_i / m_e >> 1 the time evolution of the reconnected flux
is independent of ion-electron mass ratio; also, in the case of m_i / m_e = 1
we show that reconnection proceeds slowly as the Hall term is zero; when m_i /
m_e >> 1 (i.e. the Hall term is non-zero) reconnection is fast and we
conjecture that this is due to magnetic field being frozen into electron fluid,
which moves significantly faster than ion fluid; (iii) within one Alfven time,
somewhat less than half (40%) of the initial total (roughly magnetic) energy is
converted into the kinetic energy of electrons, and somewhat more than half
(60%) into kinetic energy of ions (similar to solar flare observations); (iv)
in the strongly stressed X-point case, in about one Alfven time, a full
isotropy in all three spatial directions of the velocity distribution is seen
for super-thermal electrons (also commensurate to solar flare observations).


title:
On the Possible Experimental Detection of Non-Causal Synordination
  Patterns of Physical Events

abstract:
  With reference to a previous work, the problem of the experimental detection
of non-causal synordination patterns between two series of physical events is
examined. It is necessary that the patterns in question act in a reproducible,
or at least regular, manner, so that they can be identified by means of
statistical analysis; action on individual occasional facts cannot be proved
statistically, though it is hypothetically possible. As established in the
previous work, the first series must be constituted by microevents (Penrose R
processes), that can be amplified at the macroscopic level so that they are
translated at this level into a choice between alternatives. The obtained
result defines (by means of a structural constraint which is not, however, a
causal link) the choice between execution or non-execution of certain actions
on a macroscopic system S, without any feedback on the microevents source. A
succession of macroevents is thus generated, which makes up the second series.
Statistics of the events belonging to the second series is thus completely
defined by the probability distribution of the first series of events. In the
absence of a synordination, this is the a priori probability distribution,
which can be measured by removing the constraint between the two series. If
there is synordination, the probability distribution of the two sets of events
will deviate in a measurable manner from the expected trend once the constraint
is activated.


title:
On stability of false vacuum in supersymmetric theories with cosmic
  strings

abstract:
  We study the stability of supersymmetry breaking vacuum in the presence of
cosmic strings arising in the messenger sector. For certain ranges of the
couplings, the desired supersymmetry breaking vacua become unstable against
decay into phenomenologically unacceptable vacua. This sets constraints on the
range of allowed values of the coupling constants appearing in the models and
more generally on the chosen dynamics of gauge symmetry breaking.


title: The recurrent nova RS Oph: A possible scenario for type Ia supernovae

abstract:
  The recurrent nova RS Oph experienced an outburst in 2006, 21 years after its
previous explosion in 1985, as expected. It was observed at almost all
wavelengths, and important information about its properties is still being
extracted. We present theoretical models of the explosion of this fascinating
object, which indicate that the mass of the accreting white dwarf should be
very close to the Chandrasekhar mass, to allow for such a short recurrence
period. In addition, since models suggest that this nova ejects less mass than
it accretes, it is an excellent candidate for a thermonuclear supernova
explosion, in about $10^5-10^7$ years from now. We also analyze the emission of
soft gamma-rays by RS Oph detected with the BAT instrument onboard Swift, and
with the PCA onboard RXTE. We rule out that this emission has its origin in
radioactive decays in the expanding nova envelope.


title: Diamond representations of rank two semisimple Lie algebras

abstract:
  The present work is a part of a larger program to construct explicit
combinatorial models for the (indecomposable) regular representation of the
nilpotent factor $N$ in the Iwasawa decomposition of a semi-simple Lie algebra
$\mathfrak g$, using the restrictions to $N$ of the simple finite dimensional
modules of $\mathfrak g$. Such a description is given in \cite{[ABW]}, for the
cas $\mathfrak g=\mathfrak{sl}(n)$. Here, we give the analog for the rank 2
semi simple Lie algebras (of type $A_1\times A_1$, $A_2$, $C_2$ and $G_2$). The
algebra $\mathbb C[N]$ of polynomial functions on $N$ is a quotient, called
reduced shape algebra of the shape algebra for $\mathfrak g$. Basis for the
shape algebra are known, for instance the so called semi standard Young
tableaux (see \cite{[ADLMPPrW]}). We select among the semi standard tableaux,
the so called quasi standard ones which define a kind basis for the reduced
shape algebra.


title: Positive Polynomials and Sequential Closures of Quadratic Modules

abstract:
  Let S be a basic closed semi-algebraic set in R^n and P the corresponding
preordering in R[X_1,...,X_n]. We examine for which polynomials f there exist
identities f+\ep q \in P for all \ep>0. These are precisely the elements of the
sequential closure of P with respect to the finest locally convex topology. We
solve the open problem whether this equals the double dual cone of P, by
providing a counterexample. We then prove a theorem that allows to obtain
identities for polynomials as above, by looking at a family of
fibre-preorderings, constructed from bounded polynomials. These
fibre-preorderings are easier to deal with than the original preordering in
general. For a large class of examples we are thus able to show that either
every polynomial f that is nonnegative on S admits such representations, or at
least the polynomials from the double dual cone of P do. The results also hold
in the more general setup of arbitrary commutative algebras and quadratic
modules instead of preorderings.


title: Universal properties and structure of halo nuclei

abstract:
  The universal properties and structure of halo nuclei composed of two
neutrons (2n) and a core are investigated within an effective quantum mechanics
framework. We construct an effective interaction potential that exploits the
separation of scales in halo nuclei and treat the nucleus as an effective
three-body system. The uncertainty from higher orders in the expansion is
quantified through theoretical error bands. First, we investigate the
possibility to observe excited Efimov states in 2n halo nuclei. Based on the
experimental data, 20C is the only halo nucleus candidate to possibly have an
Efimov excited state, with an energy less than 7 keV below the scattering
threshold. Second, we study the structure of 20C and other 2n halo nuclei. In
particular, we calculate their matter form factors, radii, and two-neutron
opening angles.


title:
Superconducting and thermal properties of ex-situ Glidcop sheathed
  multifilamentary MgB2 wires

abstract:
  In DC and AC practical applications of MgB2 superconducting wires an
important role is represented by the material sheath which has to provide,
among other things, a suitable electrical and thermal stabilization. A way to
obtain a large enough amount of low resistivity material in to the conductor
architecture is to use it as external sheath. In this paper we study ex-situ
multifilamentary MgB2 wires using oxide-dispersion-strengthened copper
(GlidCop) as external sheath in order to reach a good compromise between
critical current density and thermal properties. We prepared three GlidCop
samples differing by the content of dispersed sub-microscopic Al2O3 particles.
We characterized the superconducting and thermal properties and we showed that
the good thermal conductivity together the good mechanical properties and a
reasonable critical current density make of GlidCop composite wire a useful
conductor for applications where high thermal conductivity is request at
temperature above 30K, such as Superconducting-FCL.


title:
Realisation of measured dynamics as uniquely ergodic minimal
  homeomorphisms on manifolds

abstract:
  We prove that the family of measured dynamical systems which can be realised
as uniquely ergodic minimal homeomorphisms on a given manifold (of dimension at
least two) is stable under measured extension. As a corollary, any ergodic
system with an irrational eigenvalue is isomorphic to a uniquely ergodic
minimal homeomorphism on the two-torus. The proof uses the following
improvement of Weiss relative version of Jewett-Krieger theorem: any extension
between two ergodic systems is isomorphic to a skew-product on Cantor sets.


title: Optical probes of electron correlations in solids

abstract:
  Classically the interaction between light and matter is given by the Maxwell
relations. These are briefly reviewed and will be used as a basis to discuss
several techniques that are used in optical spectroscopy. We then discuss the
quantum mechanical description of the optical conductivity based on the Kubo
formalism. This is used as a basis to understand how strong correlation effects
can be observed using optical techniques. We will discuss the use of sum rules
in the interpretation of optical experiments. Finally, we describe the effect
of including interactions between electronic and collective degrees of freedom
on optical spectra.


title: Liquid metal contact as possible element for thermotunneling

abstract:
  We investigated a possibility of application of liquid metal contacts for
devices based on thermotunneling. Electric and thermal characteristics of low
wetting contact Hg/Si, and high wetting contacts Hg/Cu were determined and
compared. We got tunneling I-V characteristics for Hg/Si, while for Hg/Cu, I-V
characteristics were ohmic. We explained tunneling I-V characteristics by
presence of nanogap between the contact materials. Heat conductance of high
wetting and low wetting contacts were compared, using calorimeter measurements.
Heat conductance of high wetting contact was 3-4 times more than of low wetting
contact. Both electric and thermal characteristics of liquid metal contact
indicated that it could be used for thermotunneling devices. We solved liquid
Cs in liquid Hg to reduce work function and make liquid metal more suitable for
room temperature cooling. Work function as low as 2.6 eV was obtained.


title:
Theoretical description of the nucleation of vapor bubbles in a
  superheated fluid

abstract:
  The nucleation of vapor bubbles within a superheated fluid is studied using
density functional theory. The nudged elastic band technique is used to find
the minimum energy pathway from the metastable uniform liquid to the stable
uniform gas thus emphasizing the analogy between the the nucleation problem and
that of chemical reactions. The result is both an accurate determination of the
critical nucleus and an unbiased description of the density profile at various
points along the path between the free energy extrema. This calculation is
compared to two other methods: the use of parametrized profiles and constrained
minimization of the free energy. The results indicate that the recent claim,
based on the constraint method, that bubble nucleation and growth involves an
activated instability is incorrect.


title:
Mutual friction in a cold color flavor locked superfluid and r-mode
  instabilities in compact stars

abstract:
  Dissipative processes acting in rotating neutron stars are essential in
preventing the growth of the r-mode instability. We estimate the damping time
of r-modes of an hypothetical compact quark star made up by color flavor locked
quark matter at a temperature $T \lesssim 0.01$ MeV. The dissipation that we
consider is due to the the mutual friction force between the normal and the
superfluid component arising from the elastic scattering of phonons with
quantized vortices. This process is the dominant one for temperatures $T
\lesssim 0.01$ MeV where the mean free path of phonons due to their
self-interactions is larger than the radius of the star and they can be
described as an ideal bosonic gas. We find that r-modes oscillations are
efficiently damped by this mechanism for pulsars rotating at frequencies of the
order of 1 Hz at most. Our analysis rules out the possibility that cold pulsars
rotating at higher frequencies are entirely made up by color flavor locked
quark matter.


title: Reversibility of Some Chordal SLE$(\kappa;\rho)$ Traces

abstract:
  We prove that, for $\kappa\in(0,4)$ and $\rho\ge (\kappa-4)/2$, the chordal
SLE$(\kappa;\rho)$ trace started from $(0;0^+)$ or $(0;0^-)$ satisfies the
reversibility property. And we obtain the equation for the reversal of the
chordal SLE$(\kappa;\rho)$ trace started from $(0;b_0)$, where $b_0>0$.


title: Center-vortex loops with one selfintersection

abstract:
  We investigate the 2D behavior of one-fold selfintersecting, topologically
stabilized center-vortex loops in the confining phase of an SU(2) Yang-Mills
theory. This coarse-graining is described by curve-shrinking evolution of
center-vortex loops immersed in a flat 2D plane driving the
renormalization-group flow of an effective `action'. We observe that the system
evolves into a highly ordered state at finite noise level, and we speculate
that this feature is connected with 2D planar high $T_c$ superconductivity in
$FeAs$ systems.


title: On local geometry of rank 3 distributions with 6-dimensional square

abstract:
  We solve the equivalence problem for rank 3 completely nonholonomic vector
distributions with 6-dimensional square on a smooth manifold of arbitrary
dimension n under very mild genericity conditions. The main idea is to consider
the projectivization of the annihilator of a given 3-dimensional distribution.
It is naturally foliated by characteristic curves, which are also called the
abnormal extremals of the distribution. The dynamics of vertical fibers along
characteristic curves defines certain curves of flags of isotropic and
coisotropic subspaces in a linear symplectic space. The problem of equivalence
of distributions can be essentially reduced to the differential geometry of
such curves.
  The class of all 3-distributions under consideration is split into a finite
number of subclasses according to the Young diagram of their flags. The local
geometry of distributions can be recovered from the properties of the symmetry
group of so-called flat curves of flags associated with this Young diagram. In
each subclass we describe the flat distribution and construct a canonical frame
for any other distribution.
  It turns out that for n>6 in the most nontrivial case the symmetry algebra of
the flat distribution can be described in terms of rational normal curves
(their secants and tangential developables) in projective spaces and its
dimension grows exponentially with respect to n.


title: Convergence of symmetric Markov chains on $\Z^d$

abstract:
  For each $n$ let $Y^n_t$ be a continuous time symmetric Markov chain with
state space $n^{-1} \Z^d$. A condition in terms of the conductances is given
for the convergence of the $Y^n_t$ to a symmetric Markov process $Y_t$ on
$\R^d$. We have weak convergence of $\{Y^n_t: t\leq t_0\}$ for every $t_0$ and
every starting point. The limit process $Y$ has a continuous part and may also
have jumps.


title:
Beam-Energy and System-Size Dependence of Dynamical Net Charge
  Fluctuations

abstract:
  We present measurements of net charge fluctuations in $Au + Au$ collisions at
$\sqrt{s_{NN}} = $ 19.6, 62.4, 130, and 200 GeV, $Cu + Cu$ collisions at
$\sqrt{s_{NN}} = $ 62.4, 200 GeV, and $p + p$ collisions at $\sqrt{s} = $ 200
GeV using the dynamical net charge fluctuations measure $\nu_{+-{\rm,dyn}}$. We
observe that the dynamical fluctuations are non-zero at all energies and
exhibit a modest dependence on beam energy. A weak system size dependence is
also observed. We examine the collision centrality dependence of the net charge
fluctuations and find that dynamical net charge fluctuations violate $1/N_{ch}$
scaling, but display approximate $1/N_{part}$ scaling. We also study the
azimuthal and rapidity dependence of the net charge correlation strength and
observe strong dependence on the azimuthal angular range and pseudorapidity
widths integrated to measure the correlation.


title:
Quantum Corrections for Translation-Invariant Renormalizable
  Non-Commutative Phi^4 Theory

abstract:
  In this paper we elaborate on the translation-invariant renormalizable Phi^4
theory in 4-dimensional non-commutative space which was recently introduced by
the Orsay group. By explicitly performing Feynman graph calculations at one
loop and higher orders we illustrate the mechanism which overcomes the UV/IR
mixing problem and ultimately leads to a renormalizable model. The obtained
results show that the IR divergences are also suppressed in the massless case,
which is of importance for the gauge field theoretic generalization of the
scalar field model.


title: METIS - the Mid-infrared E-ELT Imager and Spectrograph

abstract:
  METIS, the Mid-infrared ELT Imager and Spectrograph (formerly called MIDIR),
is a proposed instrument for the European Extremely Large Telescope (E-ELT),
currently undergoing a phase-A study. The study is carried out within the
framework of the ESO-sponsored E-ELT instrumentation studies. METIS will be
designed to cover the E-ELT science needs at wavelengths longward of 3um, where
the thermal background requires different operating schemes. In this paper we
discuss the main science drivers from which the instrument baseline has been
derived. Specific emphasis has been given to observations that require very
high spatial and spectral resolution, which can only be achieved with a
ground-based ELT. We also discuss the challenging aspects of background
suppression techniques, adaptive optics in the mid-IR, and telescope site
considerations. The METIS instrument baseline includes imaging and spectroscopy
at the atmospheric L, M, and N bands with a possible extension to Q band
imaging. Both coronagraphy and polarimetry are also being considered. However,
we note that the concept is still not yet fully consolidated. The METIS studies
are being performed by an international consortium with institutes from the
Netherlands, Germany, France, United Kingdom, and Belgium.


title: Formation of ultracold polar molecules in the rovibrational ground state

abstract:
  Ultracold LiCs molecules in the absolute ground state X$^1\Sigma^+$, v"=0,
J"=0 are formed via a single photo-association step starting from laser-cooled
atoms. The selective production of v"=0, J"=2 molecules with a 50-fold higher
rate is also demonstrated. The rotational and vibrational state of the ground
state molecules is determined in a setup combining depletion spectroscopy with
resonant-enhanced multi-photon ionization time-of-flight spectroscopy. Using
the determined production rate of up to 5x10^3 molecules/s, we describe a
simple scheme which can provide large samples of externally and internally cold
dipolar molecules.


title: Composition operators on the space of Couchy-Stiltjes transforms

abstract:
  In this note is given a new proof of the norm estimate of J. Cima and A.
Matheson.


title: Influence of boundary conditions on yielding in a soft glassy material

abstract:
  The yielding behavior of a sheared Laponite suspension is investigated within
a 1 mm gap under two different boundary conditions. No-slip conditions, ensured
by using rough walls, lead to shear localization as already reported in various
soft glassy materials. When apparent wall slip is allowed using a smooth
geometry, the sample is shown to break up into macroscopic solid pieces that
get slowly eroded by the surrounding fluidized material up to the point where
the whole sample is fluid. Such a drastic effect of boundary conditions on
yielding suggests the existence of some macroscopic characteristic length that
could be connected to cooperativity effects in jammed materials under shear.


title: The meson $Z^+(4430)$ as a tetraquark state

abstract:
  We test the validity of the QCD sum rules applied to the meson $Z^+(4430)$,
by considering a diquark-antidiquark type of current with $J^{P}=0^{-}$ and
with $J^{P}=1^{-}$. We find that, with the studied currents, it is possible to
find an acceptable Borel window. In such a Borel window we have simultaneously
a good OPE convergence and a pole contribution which is bigger than the
continuum contribution. We get $m_Z=(4.52\pm0.09)\GeV$ and
$m_Z=(4.84\pm0.14)\GeV$ for the currents with $J^{P}=0^{-}$ and $J^{P}=1^{-}$
respectively. We conclude that the QCD sum rules results favors $J^{P}=0^{-}$
quantum numbers for the $Z^+(4430)$ meson.


title: Local and nonlocal solvable structures in ODEs reduction

abstract:
  Solvable structures, likewise solvable algebras of local symmetries, can be
used to integrate scalar ODEs by quadratures. Solvable structures, however, are
particularly suitable for the integration of ODEs with a lack of local
symmetries. In fact, under regularity assumptions, any given ODE always admits
solvable structures even though finding them in general could be a very
difficult task. In practice a noteworthy simplification may come by computing
solvable structures which are adapted to some admitted symmetry algebra. In
this paper we consider solvable structures adapted to local and nonlocal
symmetry algebras of any order (i.e., classical and higher). In particular we
introduce the notion of nonlocal solvable structure.


title: Another Co*cryption Method

abstract:
  We consider the enciphering of a data stream while being compressed by a LZ
algorithm. This has to be compared to the classical encryption after
compression methods used in security protocols. Actually, most cryptanalysis
techniques exploit patterns found in the plaintext to crack the cipher;
compression techniques reduce these attacks. Our scheme is based on a LZ
compression in which a Vernam cipher has been added. We make some security
remarks by trying to measure its randomness with statistical tests. Such a
scheme could be employed to increase the speed of security protocols and to
decrease the computing power for mobile devices.


title: Jordan decomposition and dynamics on flag manifolds

abstract:
  Let $\g$ be a semisimple Lie algebra and $G = \Int(\g)$. In this article, we
relate the Jordan decomposition of $X \in \g$ (or $g \in G$) with the dynamics
induced on generalized flag manifolds by the right invariant continuous-time
flow generated by $X$ (or the discrete-time flow generated by $g$). We
characterize the recurrent set and the finest Morse decomposition (including
its stable sets) of these flows and show that its entropy always vanishes. We
characterize the structurally stable ones and compute the Conley index of the
attractor Morse component. When the nilpotent part of $X$ is trivial, we
compute the Conley indexes of all Morse components. Finally, we consider the
dynamical aspects of linear differential equations with periodic coefficients
in $\g$, which can be regarded as an extension of the dynamics generated by an
element $X \in \g$. In this context, we generalize Floquet theory and extend
the previous results to this case.


title: Bosonic super-WIMPs as keV-scale dark matter

abstract:
  We consider models of light super-weakly interacting cold dark matter, with
O(10-100) keV mass, focusing on bosonic candidates such as pseudoscalars and
vectors. We analyze the cosmological abundance, the gamma-background created by
particle decays, the impact on stellar processes due to cooling, and the direct
detection capabilities in order to identify classes of models that pass all the
constraints. In certain models, variants of photoelectric (or axioelectric)
absorption of dark matter in direct-detection experiments can provide a
sensitivity to the superweak couplings to the Standard Model which is superior
to all existing indirect constraints. In all models studied, the annual
modulation of the direct-detection signal is at the currently unobservable
level of O(10^{-5}).


title: The self-assembly of DNA Holliday junctions studied with a minimal model

abstract:
  In this paper, we explore the feasibility of using coarse-grained models to
simulate the self-assembly of DNA nanostructures. We introduce a simple model
of DNA where each nucleotide is represented by two interaction sites
corresponding to the phosphate-sugar backbone and the base. Using this model,
we are able to simulate the self-assembly of both DNA duplexes and Holliday
junctions from single-stranded DNA. We find that assembly is most successful in
the temperature window below the melting temperatures of the target structure
and above the melting temperature of misbonded aggregates. Furthermore, in the
case of the Holliday junction, we show how a hierarchical assembly mechanism
reduces the possibility of becoming trapped in misbonded configurations. The
model is also able to reproduce the relative melting temperatures of different
structures accurately, and allows strand displacement to occur.


title:
Definition of a time variable with Entropy of a perfect fluid in
  Canonical Quantum Gravity

abstract:
  The Brown-Kuchar mechanism is applied in the case of General Relativity
coupled with the Schutz model for a perfect fluid. Using the canonical
formalism and manipulating the set of modified constraints one is able to
recover the definition of a time evolution operator, i.e. a physical
Hamiltonian, expressed as a functional of gravitational variables and the
entropy.


title:
The origin of the mu_e - M_B and Kormendy relations in dwarf elliptical
  galaxies

abstract:
  The present work is aimed at studying the distribution of galaxies of
different types and luminosities along different structural scaling relations
to see whether massive and dwarf ellipticals have been shaped by the same
formation process. This exercise is here done by comparing the distribution of
Virgo cluster massive and dwarf ellipticals and star forming galaxies along the
B band effective surface brightness and effective radius vs. absolute magnitude
relations and the Kormendy relation to the predictions of models tracing the
effects of ram-pressure stripping on disc galaxies entering the cluster
environment and galaxy harassment. Dwarf ellipticals might have been formed
from low luminosity, late-type spirals that recently entered into the cluster
and lost their gas because of a ram-pressure stripping event, stopping their
activity of star formation. The perturbations induced by the abrupt decrease of
the star formation activity are sufficient to modify the structural properties
of disc galaxies into those of dwarf ellipticals. Galaxy harassment induce a
truncation of the disc and generally an increase of the effective surface
brightness of the perturbed galaxies. The lack of dynamical simulations of
perturbed galaxies spanning a wide range in luminosity prevents us to drive any
firm conclusion on a possible harassment-induced origin of the low surface
brightness dwarf elliptical galaxy population inhabiting the Virgo cluster.
Although the observed scaling relations are consistent with the idea that the
distribution of elliptical galaxies along the mentioned scaling relation is
just due to a gradual variation with luminosity of the Sersic index n, the
comparison with models indicates that dwarf ellipticals might have been formed
by a totally different process than giant ellipticals


title: Geometric description of the connecting homomorphism for Witt groups

abstract:
  We give a geometric setup in which the connecting homomorphism in the
localization long exact sequence for Witt groups decomposes as the pull-back to
the exceptional fiber of a suitable blow-up followed by a push-forward.


title: Prediction of Sunspot Cycles by Data Assimilation Method

abstract:
  Despite the known general properties of the solar cycles, a reliable forecast
of the 11-year sunspot number variations is still a problem. The difficulties
are caused by the apparent chaotic behavior of the sunspot numbers from cycle
to cycle and by the influence of various turbulent dynamo processes, which are
far from understanding. For predicting the solar cycle properties we make an
initial attempt to use the Ensemble Kalman Filter (EnKF), a data assimilation
method, which takes into account uncertainties of a dynamo model and
measurements, and allows to estimate future observational data. We present the
results of forecasting of the solar cycles obtained by the EnKF method in
application to a low-mode nonlinear dynamical system modeling the solar
$\alpha\Omega$-dynamo process with variable magnetic helicity. Calculations of
the predictions for the previous sunspot cycles show a reasonable agreement
with the actual data. This forecast model predicts that the next sunspot cycle
will be significantly weaker (by $\sim 30%$) than the previous cycle,
continuing the trend of low solar activity.


title: A note on finite abelian gerbes over toric Deligne-Mumford stacks

abstract:
  Any toric Deligne-Mumford stack is a $\mu$-gerbe over the underlying toric
orbifold for a finite abelian group $\mu$. In this paper we give a sufficient
condition so that certain kinds of gerbes over a toric Deligne-Mumford stack
are again toric Deligne-Mumford stacks.


title: The Strong Free Will Theorem

abstract:
  We strengthen "The Free Will Theorem" [1] in several ways, by replacing the
axiom FIN by a weaker axiom MIN, and also by allowing the particles' responses
to depend on past half-spaces rather than on on past light cones. This change
allows us to directly apply our theorem to relativistic theories of the GRW
type.


title:
Constructing a Knowledge Base for Gene Regulatory Dynamics by Formal
  Concept Analysis Methods

abstract:
  Our aim is to build a set of rules, such that reasoning over temporal
dependencies within gene regulatory networks is possible. The underlying
transitions may be obtained by discretizing observed time series, or they are
generated based on existing knowledge, e.g. by Boolean networks or their
nondeterministic generalization. We use the mathematical discipline of formal
concept analysis (FCA), which has been applied successfully in domains as
knowledge representation, data mining or software engineering. By the attribute
exploration algorithm, an expert or a supporting computer program is enabled to
decide about the validity of a minimal set of implications and thus to
construct a sound and complete knowledge base. From this all valid implications
are derivable that relate to the selected properties of a set of genes. We
present results of our method for the initiation of sporulation in Bacillus
subtilis. However the formal structures are exhibited in a most general manner.
Therefore the approach may be adapted to signal transduction or metabolic
networks, as well as to discrete temporal transitions in many biological and
nonbiological areas.


title: The Analysis of Rotated Vector Field for the Pendulum

abstract:
  The pendulum, in the presence of linear dissipation and a constant torque, is
a non-integrable, nonlinear differential equation. In this paper, using the
idea of rotated vector fields, derives the relation between the applied force
$\beta$ and the periodic solution, and a conclusion that the critical value of
$\beta$ is a fixed one in the over damping situation. These results are of
practical significance in the study of charge-density waves in physics.


title: Conjugation spaces and edges of compatible torus actions

abstract:
  Duistermaat introduced the concept of ``real locus'' of a Hamiltonian
manifold. In that and in others' subsequent works, it has been shown that many
of the techniques developed in the symplectic category can be used to study
real loci, so long as the coefficient ring is restricted to the integers modulo
2. It turns out that these results seem not necessarily to depend on the
ambient symplectic structure, but rather to be topological in nature. This
observation prompts the definition of ``conjugation space'' in a paper of the
two authors with V. Puppe. Our main theorem in this paper gives a simple
criterion for recognizing when a topological space is a conjugation space.


title: The evolution of planetary nebulae. V. The diffuse X-ray emission

abstract:
  Observations with space-borne X-ray telescopes revealed the existence of
soft, diffuse X-ray emission from the inner regions of planetary nebulae.
Although the existing images support the idea that this emission arises from
the hot shocked central-star wind which fills the inner cavity of a planetary
nebula, existing models have difficulties to explain the observations
consistently. We investigate how the inclusion of thermal conduction changes
the physical parameters of the hot shocked wind gas and the amount of X-ray
emission predicted by time-dependent hydrodynamical models of planetary nebulae
with central stars of normal, hydrogen-rich surface composition. The radiation
hydrodynamical models show that heat conduction leads to lower temperatures and
higher densities within a bubble and brings the physical properties of the
X-ray emitting domain into close agreement with the values derived from
observations. Depending on the central-star mass and the evolutionary phase,
our models predict X-ray [0.45--2.5 keV] luminosities between $10^{-8}$ and
$10^{-4}$ of the stellar bolometric luminosities, in good agreement with the
observations. Less than 1% of the wind power is radiated away in this X-ray
band. Although temperature, density, and also the mass of the hot bubble is
significantly altered by heat conduction, the dynamics of the whole system
remains practically the same. Heat conduction allows the construction of
nebular models which predict the correct amount of X-ray emission and at the
same time are fully consistent with the observed mass-loss rate and wind speed.
Thermal conduction must be considered as a viable physical process for
explaining the diffuse X-ray emission from planetary nebulae with closed inner
cavities. Magnetic fields must then be absent or extremely weak.


title: Coulomb gauge gluon propagator and the Gribov formula

abstract:
  We analyze the lattice SU(2) Yang-Mills theory in Coulomb gauge. We show that
the static gluon propagator is multiplicative renormalizable and takes the
simple form $D(|\vec{p}|)^{-1}=\sqrt{|\vec{p}|^2+M^4/|\vec{p}|^2}$, proposed by
Gribov through heuristic arguments many years ago. We find $M=0.88(1) {\rm GeV}
\simeq 2 \sqrt{\sigma}$.


title: Superkicks in Hyperbolic Encounters of Binary Black Holes

abstract:
  Generic inspirals and mergers of binary black holes produce beamed emission
of gravitational radiation that can lead to a gravitational recoil or kick of
the final black hole. The kick velocity depends on the mass ratio and spins of
the binary as well as on the dynamics of the binary configuration. Studies have
focused so far on the most astrophysically relevant configuration of
quasi-circular inspirals, for which kicks as large as 3,300 km/s have been
found. We present the first study of gravitational recoil in hyperbolic
encounters. Contrary to quasi-circular configurations, in which the beamed
radiation tends to average during the inspiral, radiation from hyperbolic
encounters is plunge dominated, resulting in an enhancement of preferential
beaming. As a consequence, it is possible to achieve kick velocities as large
as 10,000 km/s.


title: Superconductivity at 34.7 K in the iron arsenide Eu0.7Na0.3Fe2As2

abstract:
  EuFe2As2 is a member of the ternary iron arsenide family. Similar to BaFe2As2
and SrFe2As2, EuFe2As2 exhibits a clear anomaly in resistivity near 200 K. It
suggests that EuFe2As2 is another promising parent compound in which
superconductivity may be realized by appropriate doping. Here we report the
discovery of superconductivity in Eu0.7Na0.3Fe2As2 by partial substitution of
the europium site with sodium. ThCr2Si2 tetragonal structure, as expected for
EuFe2As2, is formed as the main phase for the composition Eu0.7Na0.3Fe2As2.
Resistivity measurement reveals a transition temperature as high as 34.7 K in
this compound, which is higher than the Tc of Eu0.5K0.5Fe2As2.


title:
Coexistence of competing orders with two energy gaps in real and
  momentum space in high-Tc superconductor Bi2Sr2-xLaxCuO6+delta

abstract:
  The superconducting phase of the high-Tc cuprates has been thought to be
described by a single d-wave pairing order parameter. Recently, there has been
growing evidence suggesting that another form of order, possibly inherited from
the pseudogap phase above Tc, may coexist with superconductivity in the
underdoped regime. Through a combined study of scanning tunneling microscopy
and angle-resolved photoemission spectroscopy, we report the observation of two
distinct gaps (a small-gap and a large-gap) that coexist both in real space and
in the anti-nodal region of momentum space in the superconducting phase of
Bi2Sr2-xLaxCuO6+delta. We show that the small-gap is associated with
superconductivity. The large-gap persists to temperatures above the transition
temperature Tc and is found to be linked to short-range charge ordering.
Remarkably, we find a strong, short-ranged correlation between the local small-
and large- gap magnitudes suggesting that the superconductivity and charge
ordering are affected by similar physical processes.


title: Unique representation domains, II

abstract:
  Given a star operation * of finite type, we call a domain R a *-unique
representation domain (*-URD) if each *-invertible *-ideal of R can be uniquely
expressed as a *-product of pairwise *-comaximal ideals with prime radical.
When * is the t-operation we call the *-URD simply a URD. Any unique
factorization domain is a URD. Generalizing and unifying results due to
Zafrullah and Brewer-Heinzer, we give conditions for a *-ideal to be a unique
*-product of pairwise *-comaximal ideals with prime radical and characterize
*-URDs. We show that the class of URDs includes rings of Krull type, the
generalized Krull domains introduced by El Baghdadi and weakly Matlis domains
whose t-spectrum is treed. We also study when the property of being a URD
extends to some classes of overrings, such as polynomial extensions, rings of
fractions and rings obtained by the D+XD_S[X] construction.