title:
Neutrino-Mass Hierarchies and Non-linear Representation of
  Lepton-Flavour Symmetry

abstract:
  Lepton-flavour symmetry in the Standard Model is broken by small masses for
charged leptons and neutrinos. Introducing neutrino masses via dimension-5
operators associated to lepton-number violation at a very high scale, the
corresponding coupling matrix may still have entries of order 1, resembling the
situation in the quark sector with large top Yukawa coupling. As we have shown
recently, in such a situation one may introduce the coupling matrices between
lepton and Higgs fields as non-linear representations of lepton-flavour
symmetry within an effective-theory framework. This allows us to separate the
effects related to the large mass difference observed in atmospheric neutrino
oscillations from those related to the solar mass difference. We discuss the
cases of normal or inverted hierarchical and almost degenerate neutrino
spectrum, give some examples to illustrate minimal lepton-flavour violation in
radiative and leptonic decays, and also provide a systematic definition of
next-to-minimal lepton-flavour violation within the non-linear framework.


title:
Strongly Enhanced Current-Carrying Performance in MgB2 Tape Conductors
  by Novel C60 Doping

abstract:
  MgB2 is a promising superconductor for important large-scale applications for
both high field magnets and cryocooler-cooled magnet operated at temperatures
around 20 K. In this work, by utilizing C60 as a viable alternative dopant, we
demonstrate a simple and industrially scaleable rout that yields a 10-15-fold
improvement in the in-high-field current densities of MgB2 tape conductors. For
example, a Jc value higher than 4x10^4 A/cm^2 (4.2 K, 10 T), which exceeds that
for NbTi superconductor, can be realized on the C60 doped MgB2 tapes. It is
worth noting that this value is even higher than that fabricated using strict
high energy ball milling technique under Ar atmosphere. At 20 K, Hirr was about
10 T for C60 doped MgB2 tapes. A large amount of nanometer-sized precipitates
and grain boundaries were found in MgB2 matrix. The special physical and
chemical characteristic of C60, in addition to its C containing intrinsic
essence, is a key point in enhancing the superconducting performance of MgB2
tapes.


title: Misaligned spin-orbit in the XO-3 planetary system?

abstract:
  The transiting extrasolar planet XO-3b is remarkable, with a high mass and
eccentric orbit. The unusual characteristics make it interesting to test
whether its orbital plane is parallel to the equator of its host star, as it is
observed for other transiting planets. We performed radial velocity
measurements of XO-3 with the SOPHIE spectrograph at the 1.93-m telescope of
Haute-Provence Observatory during a planetary transit, and at other orbital
phases. This allowed us to observe the Rossiter-McLaughlin effect and, together
with a new analysis of the transit light curve, to refine the parameters of the
planet. The unusual shape of the radial velocity anomaly during the transit
provides a hint for a nearly transverse Rossiter-McLaughlin effect. The
sky-projected angle between the planetary orbital axis and the stellar rotation
axis should be lambda = 70 +/- 15 degrees to be compatible with our
observations. This suggests that some close-in planets might result from
gravitational interaction between planets and/or stars rather than migration
due to interaction with the accretion disk. This surprising result requires
confirmation by additional observations, especially at lower airmass, to fully
exclude the possibility that the signal is due to systematic effects.


title: Encounters in the ONC - observing imprints of star-disc interactions

abstract:
  The external destruction of protoplanetary discs in a clustered environment
acts mainly due to two mechanisms: gravitational drag by stellar encounters and
evaporation by strong stellar winds and radiation. If encounters play a role in
disc destruction, one would expect that stars devoid of disc material would
show unexpectedly high velocities as an outcome of close interactions. We want
to quantify this effect by numerical simulations and compare it to
observations. As a model cluster we chose the Orion Nebula Cluster (ONC). We
found from the observational data that 8 to 18 stars leave the ONC with
velocities several times the velocity dispersion. The majority of these
high-velocity stars are young low-mass stars, among them several lacking
infrared excess emission. Interestingly, the high-velocity stars are found only
in two separate regions of the ONC. Our simulations give an explanation for the
location of the high-velocity stars and provide evidence for a strong
correlation between location and disc destruction. The high-velocity stars can
be explained as the outcome of close three-body encounters; the partial lack of
disc signatures is attributed to gravitational interaction. The spatial
distribution of the high-velocity stars reflects the initial structure and
dynamics of the ONC. Our approach can be generalized to study the evolution of
other young dense star clusters, like the Arches cluster, back in time.


title: Structure of spanning trees on the two-dimensional Sierpinski gasket

abstract:
  Consider spanning trees on the two-dimensional Sierpinski gasket SG(n) where
stage $n$ is a non-negative integer. For any given vertex $x$ of SG(n), we
derive rigorously the probability distribution of the degree $j \in
\{1,2,3,4\}$ at the vertex and its value in the infinite $n$ limit. Adding up
such probabilities of all the vertices divided by the number of vertices, we
obtain the average probability distribution of the degree $j$. The
corresponding limiting distribution $\phi_j$ gives the average probability that
a vertex is connected by 1, 2, 3 or 4 bond(s) among all the spanning tree
configurations. They are rational numbers given as $\phi_1=10957/40464$,
$\phi_2=6626035/13636368$, $\phi_3=2943139/13636368$, $\phi_4=124895/4545456$.


title: Modeling long-range memory with stationary Markovian processes

abstract:
  In this paper we give explicit examples of power-law correlated stationary
Markovian processes y(t) where the stationary pdf shows tails which are
gaussian or exponential. These processes are obtained by simply performing a
coordinate transformation of a specific power-law correlated additive process
x(t), already known in the literature, whose pdf shows power-law tails 1/x^a.
We give analytical and numerical evidence that although the new processes (i)
are Markovian and (ii) have gaussian or exponential tails their autocorrelation
function still shows a power-law decay <y(t) y(t+T)>=1/T^b where b grows with a
with a law which is compatible with b=a/2-c, where c is a numerical constant.
When a<2(1+c) the process y(t), although Markovian, is long-range correlated.
Our results help in clarifying that even in the context of Markovian processes
long-range dependencies are not necessarily associated to the occurrence of
extreme events. Moreover, our results can be relevant in the modeling of
complex systems with long memory. In fact, we provide simple processes
associated to Langevin equations thus showing that long-memory effects can be
modeled in the context of continuous time stationary Markovian processes.


title:
Parton distribution function uncertainties & nuclear corrections for the
  LHC

abstract:
  We study nuclear effects of charged current deep inelastic neutrino-iron
scattering in the framework of a chi^2 analysis of parton distribution
functions (PDFs). We extract a set of iron PDFs which are used to compute
x_Bj-dependent and Q^2-dependent nuclear correction factors for iron structure
functions which are required in global analyses of free nucleon PDFs. We
compare our results with nuclear correction factors from neutrino-nucleus
scattering models and correction factors for charged lepton-iron scattering. We
find that, except for very high x_Bj, our correction factors differ in both
shape and magnitude from the correction factors of the models and
charged-lepton scattering.


title: On lattices of maximal index two

abstract:
  The maximal index of a Euclidean lattice L of dimension n is the maximal
index of the sub-lattices of L spanned by n independent minimal vectors of L.
In this paper, we prove that a perfect lattice of maximal index two not
provided by a cross-section has dimension at most 5.


title: Modelling the excitation of acoustic modes in Alpha Cen A

abstract:
  We infer from different seismic observations the energy supplied per unit of
time by turbulent convection to the acoustic modes of Alpha Cen A (HD 128620),
a star which is similar but not identical to the Sun. The inferred rates of
energy supplied to the modes (i.e. mode excitation rates) are found to be
significantly larger than in the Sun. They are compared with those computed
with an excitation model that includes two sources of driving, the Reynolds
stress contribution and the advection of entropy fluctuations. The model also
uses a closure model, the Closure Model with Plumes (CMP hereafter), that takes
the asymmetry between the up- and down-flows (i.e. the granules and plumes,
respectively) into account. Different prescriptions for the eddy-time
correlation function are also confronted to observational data. Calculations
based on a Gaussian eddy-time correlation underestimate excitation rates
compared with the values derived from observations for Alpha Cen A. On the
other hand, calculations based on a Lorentzian eddy-time correlation lie within
the observational error bars. This confirms results obtained in the solar case.
With respect to the helioseismic data, those obtained for Alpha Cen A
constitute an additional support for our model of excitation. We show that mode
masses must be computed taking turbulent pressure into account. Finally, we
emphasize the need for more accurate seismic measurements in order to
discriminate, in the case of Alpha Cen A, between the CMP closure model and the
quasi-Normal Approximation as well as to confirm or not the need to include the
excitation by the entropy fluctuations.


title: Discrete phase-space structure of $n$-qubit mutually unbiased bases

abstract:
  We work out the phase-space structure for a system of $n$ qubits. We replace
the field of real numbers that label the axes of the continuous phase space by
the finite field $\Gal{2^n}$ and investigate the geometrical structures
compatible with the notion of unbiasedness. These consist of bundles of
discrete curves intersecting only at the origin and satisfying certain
additional properties. We provide a simple classification of such curves and
study in detail the four- and eight-dimensional cases, analyzing also the
effect of local transformations. In this way, we provide a comprehensive
phase-space approach to the construction of mutually unbiased bases for $n$
qubits.


title:
Multifractal analysis of weak Gibbs measures for non-uniformly expanding
  C^1 maps

abstract:
  We consider the local dimension spectrum of a weak Gibbs measure on a C^1
non-uniformly hyperbolic system of Manneville- Pomeau type. We present the
spectrum in three ways: using invariant measures, uniformly hyperbolic ergodic
measures and equilibrium states. We are also proving analyticity of the
spectrum under additional assumptions. All three presentations are well known
for smooth uniformly hyperbolic systems.


title: Justification of an asymptotic expansion at infinity

abstract:
  A family of asymptotic solutions at infinity for the system of ordinary
differential equations is considered. Existence of exact solutions which have
these asymptotics is proved.


title: High dimensional gaussian classification

abstract:
  High dimensional data analysis is known to be as a challenging problem. In
this article, we give a theoretical analysis of high dimensional classification
of Gaussian data which relies on a geometrical analysis of the error measure.
It links a problem of classification with a problem of nonparametric
regression. We give an algorithm designed for high dimensional data which
appears straightforward in the light of our theoretical work, together with the
thresholding estimation theory. We finally attempt to give a general treatment
of the problem that can be extended to frameworks other than gaussian.


title: Fractal distributions of dark matter and gas in the MareNostrum Universe

abstract:
  We develop a method of multifractal analysis of N-body cosmological
simulations that improves on the customary counts-in-cells method by taking
special care of the effects of discreteness and large scale homogeneity. The
analysis of the Mare-Nostrum simulation with our method provides strong
evidence of self-similar multifractal distributions of dark matter and gas,
with a halo mass function that is of Press-Schechter type but has a power-law
exponent -2, as corresponds to a multifractal. Furthermore, our analysis shows
that the dark matter and gas distributions are indistinguishable as
multifractals. To determine if there is any gas biasing, we calculate the
cross-correlation coefficient, with negative but inconclusive results. Hence,
we develop an effective Bayesian analysis connected with information theory,
which clearly demonstrates that the gas is biased in a long range of scales, up
to the scale of homogeneity. However, entropic measures related to the Bayesian
analysis show that this gas bias is small (in a precise sense) and is such that
the fractal singularities of both distributions coincide and are identical. We
conclude that this common multifractal cosmic web structure is determined by
the dynamics and is independent of the initial conditions.


title: Chow Stability of Curves of Genus 4 in P^3

abstract:
  In the paper, we study the GIT construction of the moduli space of Chow
semistable curves of genus 4 in P^3. By using the GIT method developed by
Mumford and a deformation theoretic argument, we give a modular description of
this moduli space. We classify Chow stable or Chow semistable curves when they
are irreducible or nonreduced. Then we work out the case when a curve has two
components. Our classification provides some clues to understand the birational
map from the moduli space of stable curves of genus 4 to the moduli space of
Chow semistable curves of genus 4 in P^3.


title: Quasi-compactness of transfer operators for contact Anosov flows

abstract:
  For any $C^r$ contact Anosov flow with $r\ge 3$, we construct a scale of
Hilbert spaces, which are embedded in the space of distributions on the phase
space and contain all $C^r$ functions, such that the transfer operators for the
flow extend to them boundedly and that the extensions are quasi-compact.
Further we give explicit bounds on the essential spectral radii of the
extensions in terms of the differentiability r and the hyperbolicity exponents
of the flow.


title: Constraints from the Muon g-2 on the Parameter Space of the NMSSM

abstract:
  We generalize the computation of supersymmetric contributions to the muon
anomalous magnetic moment (g-2)_mu to the NMSSM. In the presence of a light
CP-odd Higgs scalar, these can differ considerably from the MSSM. We discuss
the amount of these contributions in regions of the parameter space of the
general NMSSM compatible with constraints from B physics. In the mSUGRA-like
cNMSSM, constraints from (g-2)_mu prefer regions in parameter space
corresponding to a low SUSY breaking scale.


title:
The intrinsic hypoelliptic Laplacian and its heat kernel on unimodular
  Lie groups

abstract:
  We present an invariant definition of the hypoelliptic Laplacian on
sub-Riemannian structures with constant growth vector, using the Popp's volume
form introduced by Montgomery. This definition generalizes the one of the
Laplace-Beltrami operator in Riemannian geometry. In the case of left-invariant
problems on unimodular Lie groups we prove that it coincides with the usual sum
of squares.
  We then extend a method (first used by Hulanicki on the Heisenberg group) to
compute explicitly the kernel of the hypoelliptic heat equation on any
unimodular Lie group of type I. The main tool is the noncommutative Fourier
transform. We then study some relevant cases: SU(2), SO(3), SL(2) (with the
metrics inherited by the Killing form), and the group SE(2) of rototranslations
of the plane.
  Our study is motivated by some recent results about the cut and conjugate
loci on these sub-Riemannian manifolds. The perspective is to understand how
singularities of the sub-Riemannian distance reflect on the kernel of the
corresponding hypoelliptic heat equation.


title: On astheno-Kaehler metrics

abstract:
  A Hermitian metric on a complex manifold of complex dimension $n$ is called
{\em astheno-K\"ahler} if its fundamental $2$-form $F$ satisfies the condition
$\partial \overline \partial F^{n - 2} =0$. If $n =3$, then the metric is {\em
strong KT}, i.e. $F$ is $\partial \overline \partial$-closed. By using blow-ups
and the twist construction, we construct simply-connected astheno-K\"ahler
manifolds of complex dimension $n > 3$. Moreover, we construct a family of
astheno-K\"ahler (non strong KT) $2$-step nilmanifolds of complex dimension $4$
and we study deformations of strong KT structures on nilmanifolds of complex
dimension $3$. Finally, we study the relation between astheno-K\"ahler
condition and (locally) conformally balanced one and we provide examples of
locally conformally balanced astheno-K\"ahler metrics on $\T^2$-bundles over
(non-K\"ahler) homogeneous complex surfaces.


title:
Negative Elliptic Flow of $J/\psi$'s: A Qualitative Signature for Charm
  Collectivity at RHIC

abstract:
  We discuss one of the most prominent features of the very recent preliminary
elliptic flow data of $J/\Psi$ meson from the PHENIX collaboration
\cite{Silvestre:2008tw}. Even within the the rather large error bars of the
measured data a negative elliptic flow parameter ($v_2$) for $J/\Psi$ in the
range of $p_T=0.5-2.5 \GeV/c$ is visible. We argue that this negative elliptic
flow at intermediate $p_T$ is a clear and qualitative signature for the
collectivity of charm quarks produced in nucleus-nucleus reactions at RHIC.
Within a parton recombination approach we show that a negative elliptic flow
puts a lower limit on the collective transverse velocity of heavy quarks. The
numerical value of the transverse flow velocity $\beta_T$ for charm quarks that
is necessary to reproduce the data is $\beta_T(charm)\sim 0.55-0.6c$ and
therefore compatible with the flow of light quarks.


title: Very Special Relativity in Curved Space-Times

abstract:
  The generalization of Cohen and Glashow's Very Special Relativity to curved
space-times is considered. Gauging the SIM(2) symmetry does not, in general,
provide the coupling to the gravitational background. However, locally SIM(2)
invariant Lagrangians can always be constructed. For space-times with SIM(2)
holonomy, they describe chiral fermions propagating freely as massive
particles.


title: Supersymmetric Yang-Mills Theory From Lorentzian Three-Algebras

abstract:
  We show that by adding a supersymmetric Faddeev-Popov ghost sector to the
recently constructed Bagger-Lambert theory based on a Lorentzian three algebra,
we obtain an action with a BRST symmetry that can be used to demonstrate the
absence of negative norm states in the physical Hilbert space. We show that the
combined theory, expanded about its trivial vacuum, is BRST equivalent to a
trivial theory, while the theory with a vev for one of the scalars associated
with a null direction in the three-algebra is equivalent to a reformulation of
maximally supersymmetric 2+1 dimensional Yang-Mills theory in which there a
formal SO(8) superconformal invariance.


title:
Quantum Zeno Effect Explains Magnetic-Sensitive Radical-Ion-Pair
  Reactions

abstract:
  Chemical reactions involving radical-ion pairs are ubiquitous in biology,
since not only are they at the basis of the photosynthetic reaction chain, but
are also assumed to underlie the biochemical magnetic compass used by avian
species for navigation. Recent experiments with magnetic-sensitive radical-ion
pair reactions provided strong evidence for the radical-ion-pair
magnetoreception mechanism, verifying the expected magnetic sensitivities and
chemical product yield changes. It is here shown that the theoretical
description of radical-ion-pair reactions used since the 70's cannot explain
the observed data, because it is based on phenomenological equations masking
quantum coherence effects. The fundamental density matrix equation derived here
from basic quantum measurement theory considerations naturally incorporates the
quantum Zeno effect and readily explains recent experimental observations on
low- and high-magnetic-field radical-ion-pair reactions.


title:
Modeling And Simulation Of Prolate Dual-Spin Satellite Dynamics In An
  Inclined Elliptical Orbit: Case Study Of Palapa B2R Satellite

abstract:
  In response to the interest to re-use Palapa B2R satellite nearing its End of
Life (EOL) time, an idea to incline the satellite orbit in order to cover a new
region has emerged in the recent years. As a prolate dual-spin vehicle, Palapa
B2R has to be stabilized against its internal energy dissipation effect. This
work is focused on analyzing the dynamics of the reusable satellite in its
inclined orbit. The study discusses in particular the stability of the prolate
dual-spin satellite under the effect of perturbed field of gravitation due to
the inclination of its elliptical orbit. Palapa B2R physical data was
substituted into the dual-spin's equation of motion. The coefficient of zonal
harmonics J2 was induced into the gravity-gradient moment term that affects the
satellite attitude. The satellite's motion and attitude were then simulated in
the perturbed gravitational field by J2, with the variation of orbit's
eccentricity and inclination. The analysis of the satellite dynamics and its
stability was conducted for designing a control system for the vehicle in its
new inclined orbit.


title:
Dilatation symmetry in higher dimensions and the vanishing of the
  cosmological constant

abstract:
  A wide class of dilatation symmetric effective actions in higher dimensions
leads to a vanishing four-dimensional cosmological constant. This requires no
tuning of parameters and results from the absence of an allowed potential for
the scalar dilaton field. The field equations admit many solutions with flat
four-dimensional space and non-vanishing gauge couplings. In a more general
setting, these are candidates for asymptotic states of cosmological runaway
solutions, where dilatation symmetry is realized dynamically if a fixed point
is approached as time goes to infinity. Dilatation anomalies during the runaway
can lift the degeneracy of solutions and lead to an observable dynamical dark
energy.


title:
Vacuum effects in a vibrating cavity: time refraction, dynamical Casimir
  effect, and effective Unruh acceleration

abstract:
  Two different quantum processes are considered in a perturbed vacuum cavity:
time refraction and dynamical Casimir effect. They are shown to be physically
equivalent, and are predicted to be unstable, leading to an exponential growth
in the number of photons created in the cavity. The concept of an effective
Unruh acceleration for these processes is also introduced, in order to make a
comparison in terms of radiation efficiency, with the Unruh radiation
associated with an accelerated frame in unbounded vacuum.


title:
Onboard Multivariable Controller Design for a Small Scale Helicopter
  Using Coefficient Diagram Method

abstract:
  A mini scale helicopter exhibits not only increased sensitivity to control
inputs and disturbances, but also higher bandwidth of its dynamics. These
properties make model helicopters, as a flying robot, more difficult to
control. The dynamics model accuracy will determine the performance of the
designed controller. It is attractive in this regards to have a controller that
can accommodate the unmodeled dynamics or parameter changes and perform well in
such situations. Coefficient Diagram Method (CDM) is chosen as the candidate to
synthesize such a controller due to its simplicity and convenience in
demonstrating integrated performance measures including equivalent time
constant, stability indices and robustness. In this study, CDM is implemented
for a design of multivariable controller for a small scale helicopter during
hover and cruise flight. In the synthesis of MIMO CDM, good design common sense
based on hands-on experience is necessary. The low level controller algorithm
is designed as part of hybrid supervisory control architecture to be
implemented on an onboard computer system. Its feasibility and performance are
evaluated based on its robustness, desired time domain system responses and
compliance to hard-real time requirements.


title:
Bacterial tracking of motile algae assisted by algal cell's vorticity
  field

abstract:
  Previously published experimental work by other authors has shown that
certain motile marine bacteria are able to track free swimming algae by
executing a zigzag path and steering toward the algae at each turn. Here, we
propose that the apparent steering behaviour could be a hydrodynamic effect,
whereby an algal cell's vorticity and strain-rate fields rotate a pursuing
bacterial cell in the appropriate direction. Using simplified models for the
bacterial and algal cells, we numerically compute the trajectory of a bacterial
cell and demonstrate the plausibility of this hypothesis.


title:
Rapidity dependent $K/\pi$ ratios in Au+Au collisions at $\sqrt{s_{NN}}$
  = 62.4 GeV

abstract:
  We report on measurements of identified particle yields from Au-Au collisions
at $\sqrt{s_{NN}} = 62.4$ GeV made with the BRAHMS spectrometer. Here we will
concentrate on the charged $K/\pi$ ratios as function of rapidity and
baryo-chemical potential. We find that the $K/\pi$ ratios measured at different
rapidities in the analysed dataset have a common dependence with the same
ratios measured in mid-rapidity at SPS energies when plotted as function of the
$\bar{p}/p$ ratio. The theoretical models used for comparison, UrQMD and AMPT,
give a reasonable description of the particle yields at mid-rapidity but fail
to do so for the $K/\pi$ ratios at forward rapidity.


title:
The model of dynamo with small number of modes and magnetic activity of
  T Tauri stars

abstract:
  The model that describes operation of dynamo in fully convective stars is
presented. It is based on representation of stellar magnetic field as a
superposition of finite number of poloidal and toroidal free damping modes. In
the frame of adopted low of stellar differential rotation we estimated minimal
value of dynamo number D, starting from which generation of cyclic magnetic
field in stars without radiative core is possible. We also derived expression
for period of the cycle. It was found that dynamo cycles of fully convective
stars and stars with thin convective envelopes differ in a qualitative way: 1)
distribution of spots over latitude during the cycle is different in these
stars; 2) the model predicts that spot formation in fully convective stars
should be strongly suppressed at some phases of the cycle.
  We have analyzed historical lightcurve of WTTS star V410 Tau and found that
long term activity of the star is not periodic process. Rather one can speak
about quasi cyclic activity with characteristic time of $\sim 4$ yr and chaotic
component over imposed. We concluded also that redistribution of cool spots
over longitude is the reason of long term variations of V410 Tau brightness. It
means that one can not compare directly results of photometric observations
with predictions of our axially symmetric (for simplicity) model which allows
to investigate time evolution of spot's distribution over latitude. We then
discuss what kind of observations and in which way could be used to check
predictions of the dynamo theory.


title:
Relativistic mean-field theory applied to the study of neutron star
  properties

abstract:
  Nuclear physics can be applied in various ways to the study of neutron stars.
This thesis reports on one such application, where the relativistic mean-field
approximation has been employed to calculate the equations of state of matter
in the neutron star interior. In particular the equations of state of nuclear
and neutron star matter of the NL3, PK1 and FSUGold parameter sets were
derived. A survey of available literature on neutron stars is presented and we
use the derived equations of state to reproduce the properties of saturated
nuclear matter as well as the mass-radius relationship of a static, spherical
symmetric neutron star. Results are compared to published values of the
properties of saturated nuclear matter and to available observational data of
the mass-radius relationship of neutron stars.


title:
Generation of high-fidelity four-photon cluster state and quantum-domain
  demonstration of one-way quantum computing

abstract:
  We experimentally demonstrate a simple scheme for generating a four-photon
entangled cluster state with fidelity over 0.860 $\pm$ 0.015. We show that the
fidelity is high enough to guarantee that the produced state is distinguished
from Greenberger-Horne-Zeilinger, W, and Dicke types of genuine four-qubit
entanglement. We also demonstrate basic operations of one-way quantum computing
using the produced state and show that the output state fidelities surpass
classical bounds, which indicates that the entanglement in the produced state
essentially contributes to the quantum operation.


title: Spin glass models with Kac interactions

abstract:
  In this paper I will review my work on disordered systems -spin glass model
with two body and $p>2$ body interactions- with long but finite interaction
range $R$. I will describe the relation of these model with Mean Field Theory
in the Kac limit and some attempts to go beyond mean field.


title:
Electronic structure of oxygen-free 38K superconductor Ba1-xKxFe2As2 in
  comparison with BaFe2As2 from first principles

abstract:
  Based on first-principles FLAPW-GGA calculation, we have investigated
electronic structure of newly discovered oxygen-free 38K superconductor
Ba1-xKxFe2As2 in comparison with parent phase - tetragonal ternary iron
arsenide BaFe2As2. The density of states, magnetic properties, near-Fermi bands
compositions, together with Sommerfeld coefficients and molar Pauli
paramagnetic susceptibility are evaluated. The results allow us to classify
these systems as quasi-two-dimensional ionic metals, where the conduction is
strongly anisotropic, only happening on the (Fe-As) layers. According to our
calculations, at the hole doping of BaFe2As2 the density of states at the Fermi
level grows, and this can be a possible factor of occurrence of
superconductivity for Ba1-xKxFe2As2. On the other hand, Ba1-xKxFe2As2 lays at
the border of magnetic instability and the pairing interactions might involve
magnetic or orbital fluctuations.


title:
RXTE determination of the intermediate polar status of XSS J00564+4548,
  IGR J17195-4100, and XSS J12270-4859

abstract:
  Aims: We determine the nature of the intermediate polar candidates XSS
J00564+4548, IGR J17195-4100, and XSS J12270-4859.
  Methods: Pointed RXTE observations searched for intermediate polar
characteristics in these candidate systems.
  Results: XSS J00564+4548 exhibits a period of 465.68+-0.07 s, which we
interpret as the spin period, an energy dependent modulation depth, and a
spectrum that is fit by a 22 keV photoelectrically absorbed bremsstrahlung with
an iron line profile. IGR J17195-4100 shows several candidate periodicities and
a spectrum that is fit by a power law with an iron line. XSS J12270-4859
exhibits a candidate spin period of 859.57+-0.64 s and a spectrum that is fit
by a power law with no evidence of an iron line.
  Conclusions: XSS J00564+4548 is confirmed to be an intermediate polar. IGR
J17195-4100 and XSS J12270-4859 both show some properties of intermediate
polars, but cannot be confirmed as definite members of the class here.


title: Point contact Andreev reflection spectroscopy of NdFeAsO_0.85

abstract:
  The newly discovered oxypnictide family of superconductors show very high
critical temperatures of up to 55K. Whilst there is growing evidence that
suggests a nodal order parameter, point contact Andreev reflection spectroscopy
can provide crucial information such as the gap value and possibly the number
of energy gaps involved. For the oxygen deficient NdFeAsO0.85 with a Tc of
45.5K, we show that there is clearly a gap value at 4.2K that is of the order
of 7meV, consistent with previous studies on oxypnictides with lower Tc.
Additionally, taking the spectra as a function of gold tip contact pressure
reveals important changes in the spectra which may be indicative of more
complex physics underlying this structure.


title:
Quantum computation in decoherence-free subspace with superconducting
  devices

abstract:
  We propose a scheme to implement quantum computation in decoherence-free
subspace with superconducting devices inside a cavity by unconventional
geometric manipulation. Universal single-qubit gates in encoded qubit can be
achieved with cavity assisted interaction. A measurement-based two-qubit
Controlled-Not gate is produced with parity measurements assisted by an
auxiliary superconducting device and followed by prescribed single-qubit gates.
The measurement of currents on two parallel devices can realize a projective
measurement, which is equivalent to the parity measurement on the involved
devices.


title:
Microlensing variability in the gravitationally lensed quasar Q2237+0305
  = the Einstein Cross

abstract:
  We present the results of the first long-term (2.2 years) spectroscopic
monitoring of a gravitationally lensed quasar, namely the Einstein Cross
Q2237+0305.
  We spatially deconvolve deep VLT/FORS1 spectra to accurately separate the
spectrum of the lensing galaxy from the spectra of the quasar images. Accurate
cross-calibration of the observations at 31 epochs from October 2004 to
December 2006 is carried out using foreground stars observed simultaneously
with the quasar. The quasar spectra are further decomposed into a continuum
component and several broad emission lines.
  We find prominent microlensing events in the quasar images A and B, while
images C and D are almost quiescent on a timescale of a few months. The
strongest variations are observed in the continuum, and their amplitude is
larger in the blue than in the red, consistent with microlensing of an
accretion disk. Variations in the intensity and profile of the broad emission
lines are also reported, most prominently in the wings of the CIII] and in the
center of the CIV emission lines. During a strong microlensing episode observed
in quasar image A, the broad component of the CIII] is more magnified than the
narrow component. In addition, the emission lines with higher ionization
potentials are more magnified than the lines with lower ionization potentials,
consistent with the stratification of the broad line region (BLR) infered from
reverberation mapping observations.


title:
Homogeneous nucleation for Glauber and Kawasaki dynamics in large
  volumes at low temperatures

abstract:
  In this paper we study metastability in large volumes at low temperatures. We
consider both Ising spins subject to Glauber spin-flip dynamics and lattice gas
particles subject to Kawasaki hopping dynamics. Let $\b$ denote the inverse
temperature and let $\L_\b \subset \Z^2$ be a square box with periodic boundary
conditions such that $\lim_{\b\to\infty}|\L_\b|=\infty$. We run the dynamics on
$\L_\b$ starting from a random initial configuration where all the droplets (=
clusters of plus-spins, respectively, clusters of particles)are small. For
large $\b$, and for interaction parameters that correspond to the metastable
regime, we investigate how the transition from the metastable state (with only
small droplets) to the stable state (with one or more large droplets) takes
place under the dynamics. This transition is triggered by the appearance of a
single \emph{critical droplet} somewhere in $\L_\b$. Using potential-theoretic
methods, we compute the \emph{average nucleation time} (= the first time a
critical droplet appears and starts growing) up to a multiplicative factor that
tends to one as $\b\to\infty$. It turns out that this time grows as
$Ke^{\Gamma\b}/|\L_\b|$ for Glauber dynamics and $K\b e^{\Gamma\b}/|\L_\b|$ for
Kawasaki dynamics, where $\Gamma$ is the local canonical, respectively,
grand-canonical energy to create a critical droplet and $K$ is a constant
reflecting the geometry of the critical droplet, provided these times tend to
infinity (which puts a growth restriction on $|\L_\b|$). The fact that the
average nucleation time is inversely proportional to $|\L_\b|$ is referred to
as \emph{homogeneous nucleation}, because it says that the critical droplet for
the transition appears essentially independently in small boxes that partition
$\L_\b$.


title: The Folding Deuteron Optical Model Potentials

abstract:
  For 52 target nuclei with deuteron as projectile, we calculate the reaction
cross sections and elastic scattering angular distributions, as well as the
$\chi^2$ values for 11 kinds of deuteron optical model potentials: our global
deuteron optical potentials and 10 folding optical potentials calculated with 2
phenomenological global nucleon optical potentials given by Koning \textit{et
al}(KD) and by Varner\textit{et al}(CH89), and 8 microscopic nucleon optical
potentials with the generalized Skyrme force parameters(GS1-6) and modified
Skyrme force parameters(SKa, SKb). We find that for constructing the folding
deuteron optical potential, both SKa and SKb are the best Skyrme force
parameters of the microscopic nucleon optical potential proposed by Q. Shen
\textit{et al}.


title: A two-fluid model for violent aerated flows

abstract:
  In the study of ocean wave impact on structures, one often uses Froude
scaling since the dominant force is gravity. However the presence of trapped or
entrained air in the water can significantly modify wave impacts. When air is
entrained in water in the form of small bubbles, the acoustic properties in the
water change dramatically. While some work has been done to study
small-amplitude disturbances in such mixtures, little work has been done on
large disturbances in air-water mixtures. We propose a basic two-fluid model in
which both fluids share the same velocities and analyze some of its properties.
It is shown that this model can successfully mimic water wave impacts on
coastal structures. The governing equations are discretized by a second-order
finite volume method. Numerical results are presented for two examples: the dam
break problem and the drop test problem. It is shown that this basic model can
be used to study violent aerated flows, especially by providing fast
qualitative estimates.

categories: physics.class-ph math.AP physics.ao-ph physics.comp-ph physics.flu-dyn


title: $\kappa$-Minkowski and Snyder algebra from reparametrisation symmetry

abstract:
  Following our earlier work \cite{sunandan1, sunandan2}, we derive
noncommuting phase-space structures which are combinations of both the
$\kappa$-Minkowski and Snyder algebra by exploiting the reparametrisation
symmetry of the recently proposed Lagrangian for a point particle \cite{subir}
satisfying the exact Doubly Special Relativity dispersion relation in the
Magueijo-Smolin framework.


abstract:
  In this paper we investigate expanding Bianchi type I models with two tilted
fluids with linear equations of state. Individually the fluids have non-zero
energy fluxes w.r.t. the symmetry surfaces, but these cancel each other because
of the Codazzi constraint. Asymptotically toward the past the solutions
approach Kasner states if the speeds of sound are less than that of light. If
one of the fluids has a speed of sound that is less or equal to 1/3 of the
speed of light (radiation) then the models isotropize toward the future, but if
both fluids are stiffer than radiation then the final state is anisotropic with
non-zero Hubble-normalized shear. The significance of these results is
discussed in a broader context.


title:
Critical adsorption and critical Casimir forces for geometrically
  structured confinements

abstract:
  We study the behavior of fluids, confined by geometrically structured
substrates, upon approaching a critical point at T = Tc in their bulk phase
diagram. As generic substrate structures periodic arrays of wedges and ridges
are considered. Based on general renormalization group arguments we calculate,
within mean field approximation, the universal scaling functions for order
parameter profiles of a fluid close to a single structured substrate and
discuss the decay of its spatial variation into the bulk. We compare the excess
adsorption at corrugated substrates with the one at planar walls. The
confinement of a critical fluid by two walls generates effective critical
Casimir forces between them. We calculate corresponding universal scaling
functions for the normal critical Casimir force between a flat and a
geometrically structured substrate as well as the lateral critical Casimir
force between two identically patterned substrates.


title:
Shortcoming of spectral filtering in semiconductor-based entangled
  photon sources

abstract:
  We theoretically investigate the production of polarization-entangled photons
through the biexciton cascade decay in a single semiconductor quantum dot. To
accomplish a high degree of entanglement, despite the exciton finestructure
splitting, one must either energetically align the two exciton states by means
of external fields or erase the which-path information by post-selecting
photons within the correct frequency range. Here we show that in the latter
scheme, as well as in related proposals, the photon state becomes deteriorated
through dephasing processes in the solid, and the degree of entanglement
remains low despite filtering.


title: On the origin of field O-type stars

abstract:
  Aims: We try to identify the origins of field O-stars in the nearest 2 to 3
kpc around the Sun using the best presently available kinematic data on O-stars
and on young open clusters. We investigate the question if the present-day data
are consistent with the assumption that O-stars have formed in groups
(clusters, associations), or in isolation. Methods: We apply the epicycle
theory for back-tracing the orbits of O-type stars and of candidate parent open
clusters. Results: From the 370 O-stars in the ``Galactic O star catalog v
2.0'' (GOSV2) we have investigated 93 stars classified as "field", and found
the origin for 73 of them in 48 open clusters younger than 30 Myrs. Only for 32
stars or about 9% of all O-stars from this catalogue, the question of their
origin in groups is not solved; some of them may have originated in isolation
or may have disintegrated the group in which they formed. Fifty percent of the
young open clusters (age < 30 Myr) in the ``Catalogue of Open Cluster Data''
(COCD) have O-stars as members, or have ejected at least one O-star in the
first 10 Myrs of their life, or both. During this period the average mass loss
from open clusters by ejecting O-stars is found to be 3 to 5 M_Sun per Myr. We
prove that zeta Pup had its origin in the open cluster Trumpler 10 which it
left about 2.5 Myrs ago, and that its present-day distance is 300 pc (compared
to 440 pc before). The revised distance implies a significant revision of the
stellar parameters (a radius of 14 R_Sun, a mass of 22.5 M_Sun, and a
luminosity of log L/L_Sun of 5.74) i.e, zeta Pup is closer, less massive, and
less luminous than previously thought. Our findings provide independent
estimates of the present-day distances and absolute magnitudes of field
O-stars.


title: Strange hadron elliptic flow from 200 GeV Cu+Cu collisions

abstract:
  Collective flow reflects dynamical evolution in high-energy heavy ion
collisions. In particular, the strange hadron elliptic flow reflects early
collision dynamics. We present results from a systematic analysis of the
centrality dependence of strange hadron elliptic flow ($v_2$) measurement of
$K_{S}^{0}$, $\Lambda$ and $\Xi$ for Cu + Cu collisions at 200 GeV. Results for
Cu + Cu collisions are compared with results previously reported for Au + Au
collisions. We will also compare our data with results from ideal hydrodynamic
calculations.


title:
Universality of QCD traveling-waves with running coupling beyond leading
  logarithmic accuracy

abstract:
  We discuss the solutions of QCD evolution equations with saturation in the
high energy limit. We present a general argument showing that, in the running
coupling case, the Next-to-Leading-Logarithmic (NLL) and higher order terms are
irrelevant for the universal asymptotic features of the solutions.


title:
Effective temperatures and activated dynamics for a two-dimensional
  air-driven granular system on two approaches to jamming

abstract:
  We present experiments on several distinct effective temperatures in a
granular system at a sequence of increasing packing densities and at a sequence
of decreasing driving rates. This includes single-grain measurements based on
the mechanical energies of both the grains and an embedded oscillator, as well
as a collective measurement based on the Einstein relation between diffusivity
and mobility, which all probe different time scales. Remarkably, all effective
temperatures agree. Furthermore, mobility data along the two trajectories
collapse when plotted vs effective temperature and exhibit an Arrhenius form
with the same energy barrier as the microscopic relaxation time.


title: Palatini f(R) gravity as a fixed point

abstract:
  In the context of modified gravity, we point out how the Palatini version of
these theories is singled out as a very special case corresponding to the
unique fixed point of a transformation involving a special conformal rescaling
of the metric. This mathematical peculiarity signals deeply rooted problems
which make the theory unphysical.


title: External magnetic field effects on a distorted kagome antiferromagnet

abstract:
  We report bulk magnetization, and elastic and inelastic neutron scattering
measurements under an external magnetic field, $H$, on the weakly coupled
distorted kagome system, Cu_{2}(OD)_3Cl. Our results show that the ordered
state below 6.7 K is a canted antiferromagnet and consists of large
antiferromagnetic $ac$-components and smaller ferromagnetic $b$-components. By
first-principle calculations and linear spin wave analysis, we present a simple
spin hamiltonian with non-uniform nearest neighbor exchange interactions
resulting in a system of coupled spin trimers with a single-ion anisotropy that
can qualitatively reproduce the spin dynamics of Cu_{2}(OD)_3Cl.


title: Polymer Quantum Dynamics of the Taub Universe

abstract:
  Within the framework of non-standard (Weyl) representations of the canonical
commutation relations, we investigate the polymer quantization of the Taub
cosmological model. The Taub model is analyzed within the Arnowitt-Deser-Misner
reduction of its dynamics, by which a time variable arises. While the energy
variable and its conjugate momentum are treated as ordinary Heisenberg
operators, the anisotropy variable and its conjugate momentum are represented
by the polymer technique. The model is analyzed at both classical and quantum
level. As a result, classical trajectories flatten with respect to the
potential wall, and the cosmological singularity is not probabilistically
removed. In fact, the dynamics of the wave packets is characterized by an
interference phenomenon, which, however, is not able to stop the evolution
towards the classical singularity.


title: Probing gluon shadowing with forward photons at RHIC

abstract:
  There is a major need to better constrain nuclear parton densities in order
to provide reliable perturbative QCD predictions at the LHC as well as to probe
possible non-linear evolution at small values of x. In these proceedings, we
discuss how the production of prompt photons at large rapidity in p-p and d-Au
collisions at RHIC (sqrt(s_NN)=200 GeV) is sensitive to the nuclear
modifications of gluon distributions at x~0.001 and at rather low scales,
Q^2~10 GeV^2. The nuclear production ratio, R_dAu=sigma(d+A->gamma+X)/(2A
sigma(p+p->gamma X), is computed for isolated prompt photons at NLO using the
nDSg nuclear parton densities, in order to assess the visibility of the signal.
We also emphasise that the expected counting rates in a year of running at RHIC
are large, indicating that R_dAu could be measured with a high statistical
accuracy.


title: Charging Induced Emission of Neutral Atoms from NaCl Nanocube Corners

abstract:
  Detachment of neutral cations/anions from solid alkali halides can in
principle be provoked by donating/subtracting electrons to the surface of
alkali halide crystals, but generally constitutes a very endothermic process.
However, the amount of energy required for emission is smaller for atoms
located in less favorable positions, such as surface steps and kinks. For a
corner ion in an alkali halide cube the binding is the weakest, so it should be
easier to remove that atom, once it is neutralized. We carried out first
principles density functional calculations and simulations of neutral and
charged NaCl nanocubes, to establish the energetics of extraction of
neutralized corner ions. Following hole donation (electron removal) we find
that detachment of neutral Cl corner atoms will require a limited energy of
about 0.8 eV. Conversely, following the donation of an excess electron to the
cube, a neutral Na atom is extractable from the corner at the lower cost of
about 0.6 eV. Since the cube electron affinity level (close to that a NaCl(100)
surface state, which we also determine) is estimated to lie about 1.8 eV below
vacuum, the overall energy balance upon donation to the nanocube of a zero
energy electron from vacuum will be exothermic. The atomic and electronic
structure of the NaCl(100) surface, and of the nanocube Na and Cl corner
vacancies are obtained and analyzed as a byproduct.


title: Feynman operator calculus and singular quantum oscillator

abstract:
  New applications of Feynman disentangling method in quantum mechanics are
studied and the time-dependent singular oscillator problem is solved in this
approach. The important role of representation group theory is discussed in
this context.


title: \"Uber Pro-p-Fundamentalgruppen markierter arithmetischer Kurven

abstract:
  Let k be a global field, p an odd prime number different from char(k) and S,
T disjoint, finite sets of primes of k. Let G_S^T(k)(p)=Gal(k_S^T(p)|k) be the
Galois group of the maximal p-extension of k which is unramified outside S and
completely split at T. We prove the existence of a finite set of primes S_0,
which can be chosen disjoint from any given set M of Dirichlet density zero,
such that the cohomology of G_{S\cup S_0}^T(k)(p) coincides with the etale
cohomology of the associated marked arithmetic curve. In particular, cd
G_{S\cup S_0}^T(k)(p)=2. Furthermore, we can choose S_0 in such a way that
k_{S\cup S_0}^T(p) realizes the maximal p-extension k_\p(p) of the local field
k_\p for all \p\in S\cup S_0, the cup-product H^1(G_{S\cup S_0}^T(k)(p),\F_p)
\otimes H^1(G_{S\cup S_0}^T(k)(p),\F_p) --> H^2(G_{S\cup S_0}^T(k)(p),\F_p) is
surjective and the decomposition groups of the primes in S establish a free
product inside G_{S\cup S_0}^T(k)(p). This generalizes previous work of the
author where similar results were shown in the case T=\emptyset under the
restrictive assumption p\nmid Cl(k) and \zeta_p\notin k.


title: Effective t-J model of pairing: singlet versus triplet

abstract:
  The t-J model is regarded as a canonical model of spin-singlet pairing
induced by the {\em kinetic exchange interaction} responsible also for an
antiferromagnetic ordering in the strongly correlated narrow-band systems. In
the orbitally degenerate systems both ferromagnetic and antiferromagnetic
kinetic exchange interactions occur. I review briefly the analogy between the
singlet and triplet types of pairing, as well as draw some general conclusions
about the pairing induced by these exchange interactions. The general
discussion is also illustrated with a concrete case of a two-dimensional
lattice with the spin triplet pairing.


title: DFT-based Conformational Analysis of a Phospholipid Molecule (DMPC)

abstract:
  The conformational space of the dimyristoyl phosphatidylcholine (DMPC)
molecule has been studied using Density Functional Theory (DFT), augmented with
a damped empirical dispersion energy term (DFT-D). Fourteen ground-state
isomers have been found with total energies within less than 1 kcal/mol.
Despite differences in combinations of their torsion angles, all these
conformers share a common geometric profile, which includes a balance of
attractive, repulsive and constraint forces between and within specific groups
of atoms. The definition of this profile fits with most of the structural
characteristics deduced from measured NMR properties of DMPC solutions. The
calculated vibrational spectrum of the molecule is in good agreement with
experimental data obtained for DMPC bilayers. These results support the idea
that DMPC molecules preserve their individual molecular structures in the
various assemblies.


title:
Neon and oxygen in low activity stars: towards a coronal unification
  with the Sun

abstract:
  The disagreement between helioseismology and a recent downward revision of
solar abundances has resulted in a controversy about the true neon abundance of
the Sun and other stars. We investigated XMM-Newton and Chandra high-resolution
X-ray spectra of weakly and moderately active stars (log L_x/L_bol = -5...-7)
and determined their coronal Ne/O abundance ratio by using two linear
combinations of strong emission lines as well as a global-fitting method. The
sample stars show a correlation between their Ne/O ratio and stellar activity
in the sense that stars with a higher activity level show a higher Ne/O ratio.
We find that the Ne/O ratio decreases in our sample from values of Ne/O~0.4
down to Ne/O~0.2, suggesting that ratios similar to 'classical' solar values
are rather common for low activity stars. A significantly enhanced neon
abundance as the solution to the solar modeling problem seems unlikely. We find
no indications of a peculiar position of the Sun among other stars.


title:
Technical improvements and performances of SpIOMM: an imaging Fourier
  transform spectrometer for astronomy

abstract:
  We present the most recent technical improvements on SpIOMM, an Imaging
Fourier Transform Spectrometer (IFTS) attached to the 1.6 telescope of the Mont
M\'egantic Observatory. The recent development of SpIOMM demonstrates that the
concept of IFTS for ground telescopes is a promising astronomical 3D
spectroscopy technique for multi-object spectroscopy and multi-band imaging.
SpIOMM has been developed through a collaboration between Universit\'e Laval
and the industry (ABB Bomem). It is designed for optical observations from the
near UV (350 nm) to the near IR (850 nm) with variable spectral resolution. The
circular FOV of the instrument covers 12 arcmin in diameter. We have recently
improved the servo system algorithm which now controls the mirror displacement
and alignment at a rate of ~7000Hz. Hardware improvements to the servo and the
metrology system will be described along with their impacts on performance in
the laboratory and in observing conditions. The instrument has successfully
been operated at the 1.6 meter telescope this year using the revised control
systems and acquired several datacubes. We will discuss some issues regarding
the sensitivity to environmental conditions implied by the use of such an
instrument. An overview of the datacube reduction procedure will show some
solutions proposed for observational problems encountered that affect the
quality of the data such as sky transmission variations, wind, changing gravity
vector and temperature.


title: On Triple Veronese Embeddings of $\PP_n$ in the Grassmannians

abstract:
  We classify all the embeddings of $\mathbb{P}_n$ in a Grassmannian $Gr(1,N)$
such that the composition with Pl\"{u}cker embedding is given by a linear
system of cubics on $\mathbb{P}_n$. As a corollary in the direction of the
Hartshorne conjecture, we prove that every vector bundle giving such an
embedding, splits if $n\geq 3$.


title: Magnetic virial identities, weak dispersion and Strichartz inequalities

abstract:
  We show a family of virial-type identities for the Schr\"odinger and wave
equations with electromagnetic potentials. As a consequence, some weak
dispersive inequalities in space dimension $n\geq3$, involving Morawetz and
smoothing estimates, are proved; finally, we apply them to prove Strichartz
inequalities for the wave equation with a non-trapping electromagnetic
potential with almost Coulomb decay.


title: Robustness of Highly Entangled Multi-Qubit States Under Decoherence

abstract:
  We investigate the decay of entanglement, due to decoherence, of multi-qubit
systems that are initially prepared in highly (in some cases maximally)
entangled states. We assume that during the decoherence processes each qubit of
the system interacts with its own, independent environment. We determine, for
systems with a small number of qubits and for various decoherence channels, the
initial states exhibiting the most robust entanglement. We also consider a
restricted version of this robustness optimization problem, only involving
states equivalent under local unitary transformations to the |GHZ> state.


title:
Critical evaluation of the neoclassical model for the equilibrium
  electrostatic field in a tokamak

abstract:
  The neoclassical prescription to use an equation of motion to determine the
electrostatic field within a tokamak plasma is fraught with difficulties.
Herein we examine two popular expressions for the equilibrium electrostatic
field so determined and show that one fails to withstand a formal scrutiny
thereof while the other fails to respect the vector nature of the diamagnetic
current. Reconsideration of the justification for the presence of the
equilibrium electrostatic field indicates that no field is needed for a neutral
plasma when considering the net bound current defined as the curl of the
magnetization. With any shift in the toroidal magnetic flux distribution, a
dynamic electric field is generated with both radial and poloidal components,
providing an alternate explanation for any measurements thereof.


title:
High-Field Pauli-Limiting Behavior and Strongly Enhanced Upper Critical
  Magnetic Fields near the Transition Temperature of an Arsenic-Deficient
  LaO_0.9F_0.1FeAs_(1-\delta) Superconductor

abstract:
  We report upper critical field B_c2(T) data for disordered
(arsenic-deficient) LaO_0.9F_0.1FeAs_(1-delta) in a wide temperature and
magnetic field range up to 47 T. Because of the large linear slope of Bc2 about
-5.4 T/K to -6.6 T/K near Tc = 28.5 K the T-dependence of the in-plane Bc2(T)
shows a flattening near 23 K above 30 T which points to Pauli-limited behavior
with Bc2(0) about 63-68 T. Our results are discussed in terms of disorder
effects within conventional and unconventional superconducting pairings.


title: Non-commutative Hardy inequalities

abstract:
  We extend Hardy's inequality from sequences of non-negative numbers to
sequences of positive semi-definite operators if the parameter p satisfies
1<p<=2, and to operators under a trace for arbitrary p>1. Applications to trace
functions are given. We introduce the tracial geometric mean and generalize
Carleman's inequality.
  Key words and phrases: Hardy's inequality, positive operator, trace function,
geometric mean, Carleman's inequality.


title:
Phase-field model for the Rayleigh--Taylor instability of immiscible
  fluids

abstract:
  The Rayleigh--Taylor instability of two immiscible fluids in the limit of
small Atwood numbers is studied by means of a phase-field description. In this
method the sharp fluid interface is replaced by a thin, yet finite, transition
layer where the interfacial forces vary smoothly. This is achieved by
introducing an order parameter (the phase field) whose variation is continuous
across the interfacial layers and is uniform in the bulk region. The phase
field model obeys a Cahn--Hilliard equation and is two-way coupled to the
standard Navier--Stokes equations. Starting from this system of equations we
have first performed a linear analysis from which we have analytically
rederived the known gravity-capillary dispersion relation in the limit of
vanishing mixing energy density and capillary width. We have performed
numerical simulations and identified a region of parameters in which the known
properties of the linear phase (both stable and unstable) are reproduced in a
very accurate way. This has been done both in the case of negligible viscosity
and in the case of nonzero viscosity. In the latter situation only upper and
lower bounds for the perturbation growth-rate are known. Finally, we have also
investigated the weakly-nonlinear stage of the perturbation evolution and
identified a regime characterized by a constant terminal velocity of
bubbles/spikes. The measured value of the terminal velocity is in perfect
agreement with available theoretical prediction. The phase-field approach thus
appears to be a valuable tecnhique for the dynamical description of the stages
where hydrodynamic turbulence and wave-turbulence enter into play.


title:
Collaborative model of interaction and Unmanned Vehicle Systems'
  interface

abstract:
  The interface for the next generation of Unmanned Vehicle Systems should be
an interface with multi-modal displays and input controls. Then, the role of
the interface will not be restricted to be a support of the interactions
between the ground operator and vehicles. Interface must take part in the
interaction management too. In this paper, we show that recent works in
pragmatics and philosophy provide a suitable theoretical framework for the next
generation of UV System's interface. We concentrate on two main aspects of the
collaborative model of interaction based on acceptance: multi-strategy approach
for communicative act generation and interpretation and communicative
alignment.


title:
Broadband electrical detection of spin excitations in (Ga,Mn)As using a
  photovoltage technique

abstract:
  We report on microwave photovoltage and simultaneous magnetotransport
measurements in a (Ga,Mn)As film oriented normal to the magnetic field. We
detect the ferromagnetic resonance over a broad frequency range of 2 GHz to
18.5 GHz and determine the spectroscopic g-factor and separate the Gilbert from
the inhomogeneous contribution to magnetization relaxation. Temperature
dependent measurements below the saturation magnetization indicate that the
photovoltage signal can serve as a sensitive tool to study the crystal
anisotropy. We demonstrate that the combination of spin dynamics with charge
transport is a promising tool to study microstructured ferromagnetic
semiconductor samples.


title: Upper bounds for the moments of zeta prime rho

abstract:
  Assuming the Riemann Hypothesis, we obtain an upper bound for the 2k-th
moment of the derivative of the Riemann zeta-function averaged over the
non-trivial zeros of $\zeta(s)$ for every positive integer k. Our bounds are
nearly as sharp as the conjectured asymptotic formulae for these moments. The
proof is based upon a recent method of K. Soundararajan that provides analogous
bounds for continuous moments of the Riemann zeta-function as well as for
moments L-functions at the central point, averaged over families.


title: Power reductivity over an arbitrary base

abstract:
  Our starting point is Mumford's conjecture, on representations of Chevalley
groups over fields, as it is phrased in the preface of "Geometric Invariant
Theory". After extending the conjecture appropriately, we show that it holds
over an arbitrary commutative base ring. We thus obtain the first fundamental
theorem of invariant theory (often referred to as Hilbert's fourteenth problem)
over an arbitrary Noetherian ring. We also prove results on the Grosshans
graded deformation of an algebra in the same generality. We end with tentative
finiteness results for rational cohomology over the integers.


title: Relaxation time of a CFT plasma at finite coupling

abstract:
  Following recent formulation of second order relativistic viscous
hydrodynamics for conformal fluids, we compute finite coupling corrections to
the relaxation time of N=4 supersymmetric Yang-Mills plasma. The result is
expected to be universal for any strongly coupled conformal gauge theory plasma
in four dimensions.


title: Is \phi^4 theory trivial ?

abstract:
  The four-dimensional \phi^4 theory is usually considered to be trivial in the
continuum limit. In fact, two definitions of triviality were mixed in the
literature. The first one, introduced by Wilson, is equivalent to positiveness
of the Gell-Mann -- Low function \beta(g) for g\ne 0; it is confirmed by all
available information and can be considered as firmly established. The second
definition, introduced by mathematical community, corresponds to the true
triviality, i.e. principal impossibility to construct continuous theory with
finite interaction at large distances: it needs not only positiveness of
\beta(g) but also its sufficiently quick growth at infinity. Indications of
true triviality are not numerous and allow different interpretation. According
to the recent results, such triviality is surely absent.


title: On slowdown and speedup of transient random walks in random environment

abstract:
  We consider one-dimensional random walks in random environment which are
transient to the right. Our main interest is in the study of the sub-ballistic
regime, where at time $n$ the particle is typically at a distance of order
$O(n^\kappa)$ from the origin, $\kappa\in(0,1)$. We investigate the
probabilities of moderate deviations from this behaviour. Specifically, we are
interested in quenched and annealed probabilities of slowdown (at time $n$, the
particle is at a distance of order $O(n^{\nu_0})$ from the origin, $\nu_0\in
(0,\kappa)$), and speedup (at time $n$, the particle is at a distance of order
$n^{\nu_1}$ from the origin, $\nu_1\in (\kappa,1)$), for the current location
of the particle and for the hitting times. Also, we study probabilities of
backtracking: at time $n$, the particle is located around $(-n^\nu)$, thus
making an unusual excursion to the left. For the slowdown, our results are
valid in the ballistic case as well.


title:
Long Cycles in the Infinite-Range-Hopping Bose-Hubbard Model with Hard
  Cores

abstract:
  In this paper we study the relation between long cycles and Bose-Condensation
in the Infinite range Bose-Hubbard Model with a hard core interaction. We
calculate the density of particles on long cycles in the thermodynamic limit
and find that the existence of a non-zero long cycle density coincides with the
occurrence of Bose-Einstein condensation but this density is not equal to that
of the Bose condensate.


title:
Comment on ``Rotation Velocities and Radial Electric Field in the Plasma
  Edge''

abstract:
  The calculation presented in "Rotation Velocities and Radial Electric Field
in the Plasma Edge" by W. M. Stacey [Contrib. Plasma Phys. 46, (2006)] contains
an inconsistent treatment of the electrostatic potential. Comparing the
expressions for the potential associated with the radial electrostatic field
with that associated with the poloidal electrostatic field reveals the
inconsistency. A field-theoretic perspective implies that the electrostatic
field must vanish in a model based upon the physics of a neutral, conducting
fluid.


title:
The changing accretion states of the intermediate polar MU
  Camelopardalis

abstract:
  We study the timing and spectral properties of the intermediate polar MU
  Camelopardalis (1RXS J062518.2+733433) to determine the accretion modes and
the accretion geometry from multi-wavelength, multi-epoch observational data.
Light curves in different observed energy ranges (optical, UV, X-ray) are
extracted. The timescales of variability in these light curves are determined
using Analysis of Variance. Phase-resolved X-ray spectra are created with
respect to the most prominent detected periodicities and each fitted with an
identical model, to quantify the differences in the fitted components. The
published tentative value for the spin period is unambiguously identified with
the rotation period of the white dwarf. We detect a distinct soft X-ray
component that can be reproduced well by a black body. The analysis of data
obtained at different epochs demonstrates that the system is changing its
accretion geometry from disk-dominated to a combination of disk- plus
stream-dominated, accompanied with a significant change in brightness at
optical wavelengths.


title: Landau-Zener Probability Reviewed

abstract:
  We examine the survival probability for neutrino propagation through matter
with variable density. We present a new method to calculate the level-crossing
probability that differs from Landau's method by constant factor, which is
relevant in the interpretation of neutrino flux from supernova explosion.


title:
Intermediate Phase in Germanium-Selenide glasses: A Theoretical and
  Experimental Study

abstract:
  A theoretical and experimental study of the Intermediate Phase (IP) in
GexSe1-x is presented. Based on ab initio molecular dynamics (MD) models of
these glasses, a generic atomic picture of the IP is discussed thoroughly.
X-Ray Absorption Near Edge Structure (XANES) measurements on Ge-Se glasses over
a wide range including the IP window are presented to show the electronic
signature of the IP in the form of the shift in the absorption edge with the Ge
content. It is shown that MD based models clearly reproduce that shift.


title: On the nature of inertial mass

abstract:
  It is shown that gravitational nature of inertial mass (Mach principle)
agrees with idea of interaction of gravitational and electromagnetic forces and
does not contradict the laws of classical mechanics. According to the simple
phenomenological model the body inertial mass is directly proportional to its
gravitational mass and the sum of coefficients, which characterize degrees of
interaction of gravitational forces in accelerated motion of the body in
accompanying and opposite directions relative to the gravitational force.


title: ULTRACAM photometry of eclipsing cataclysmic variable stars

abstract:
  The accurate determination of the masses of cataclysmic variable stars is
critical to our understanding of their origin, evolution and behaviour.
Observations of cataclysmic variables also afford an excellent opportunity to
constrain theoretical physical models of the accretion discs housed in these
systems. In particular, the brightness distributions of the accretion discs of
eclipsing systems can be mapped at a spatial resolution unachievable in any
other astrophysical situation. This thesis addresses both of these important
topics via the analysis of the light curves of six eclipsing dwarf novae,
obtained using ULTRACAM, a novel high-speed imaging photometer.


title: The Self-Gravity of Pressure in Neutron Stars

abstract:
  Following an earlier analysis which examined the effect of the self-gravity
of pressure on big-bang nucleosynthesis (BBN), we explore the effect of
pressure's self-gravity on the structure of neutron stars. We construct an ad
hoc modification of the Tolman-Oppenheimer-Volkoff equation wherein pressure's
self-gravity is parameterized by a constant, $\chi$, with $0 \le \chi \le 1$.
The full general relativistic contribution to the gravity of pressure is
recovered with $\chi = 1$, and is eliminated when $\chi = 0$. This formulation
is not proposed as an alternative theory of gravity, but is merely used to
quantify the extent to which the self-gravity of pressure contributes to the
structure of dense objects. As can be surmised qualitatively, neutron star
masses can be quite sensitive to $\chi$, with higher values of neutron-star
mass (by $\sim$20--25%) allowed for smaller values of $\chi$. However, for a
given equation of state, neither the range of neutron star radii nor the radii
at fixed central density depend sensitively on $\chi$. Over the neutron star
mass range measured so far, the presence or absence of pressure's self-gravity
yields a nearly immeasurable change in radius -- much smaller than the
variations in radius due to the uncertainty in the equation of state. In
contrast to the result for BBN, we thus find that neutron stars are not likely
to be useful testbeds for examining the self-gravity of pressure.


title: Mixed succession rules: the commutative case

abstract:
  We begin a systematic study of the enumerative combinatorics of mixed
succession rules, which are succession rules such that, in the associated
generating tree, the nodes are allowed to produce their sons at several
different levels according to different production rules. Here we deal with a
specific case, namely that of two different production rules whose rule
operators commute. In this situation, we are able to give a general formula
expressing the sequence associated with the mixed succession rules in terms of
the sequences associated with the component production rules. We end by
providing some examples illustrating our approach.


title: Riemannian and filamentary geometries..

abstract:
  Riemannian and filamentary geometries are used to investigate the stretched
filamentary dynamos against solar data in solar corona.


title: Semi-classical scattering in two dimensions

abstract:
  The semi-classical limit of quantum-mechanical scattering in two dimensions
(2D) is developed. We derive the Wentzel-Kramers-Brillouin and Eikonal results
for 2D scattering. No backward or forward glory scattering is present in 2D.
Other phenomena, such as rainbow or orbiting do show up.


title:
Continuous Spin Mean-Field models: Limiting kernels and Gibbs Properties
  of local transforms

abstract:
  We extend the notion of Gibbsianness for mean-field systems to the set-up of
general (possibly continuous) local state spaces. We investigate the Gibbs
properties of systems arising from an initial mean-field Gibbs measure by
application of given local transition kernels. This generalizes previous
case-studies made for spins taking finitely many values to the first step in
direction to a general theory, containing the following parts: (1) A formula
for the limiting conditional probability distributions of the transformed
system. It holds both in the Gibbs and non-Gibbs regime and invokes a
minimization problem for a "constrained rate-function". (2) A criterion for
Gibbsianness of the transformed system for initial Lipschitz-Hamiltonians
involving concentration properties of the transition kernels. (3) A continuity
estimate for the single-site conditional distributions of the transformed
system. While (2) and (3) have provable lattice-counterparts, the
characterization of (1) is stronger in mean-field. As applications we show
short-time Gibbsianness of rotator mean-field models on the (q-1)-dimensional
sphere under diffusive time-evolution and the preservation of Gibbsianness
under local coarse-graining of the initial local spin space.


title:
Conformal generally covariant quantum field theory: The scalar field and
  its Wick products

abstract:
  In this paper we generalize the construction of generally covariant quantum
theories given in the work of Brunetti, Fredenhagen and Verch to encompass the
conformal covariant case. After introducing the abstract framework, we discuss
the massless conformally coupled Klein Gordon field theory, showing that its
quantization corresponds to a functor between two certain categories. At the
abstract level, the ordinary fields, could be thought as natural
transformations in the sense of category theory. We show that, the Wick
monomials without derivatives (Wick powers), can be interpreted as fields in
this generalized sense, provided a non trivial choice of the renormalization
constants is given. A careful analysis shows that the transformation law of
Wick powers is characterized by a weight, and it turns out that the sum of
fields with different weights breaks the conformal covariance. At this point
there is a difference between the previously given picture due to the presence
of a bigger group of covariance. It is furthermore shown that the construction
does not depend upon the scale mu appearing in the Hadamard parametrix, used to
regularize the fields. Finally, we briefly discuss some further examples of
more involved fields.


title:
Heat transfer in sunspot penumbrae. Origin of dark-cored penumbral
  filaments

abstract:
  Context: Observations at 0.1" have revealed the existence of dark cores in
the bright filaments of sunspot penumbrae. Expectations are high that such
dark-cored filaments are the basic building blocks of the penumbra, but their
nature remains unknown.
  Aims: We investigate the origin of dark cores in penumbral filaments and the
surplus brightness of the penumbra. To that end we use an uncombed penumbral
model.
  Methods: The 2D stationary heat transfer equation is solved in a stratified
atmosphere consisting of nearly horizontal magnetic flux tubes embedded in a
stronger and more vertical field. The tubes carry an Evershed flow of hot
plasma.
  Results: This model produces bright filaments with dark cores as a
consequence of the higher density of the plasma inside the tubes, which shifts
the surface of optical depth unity toward higher (cooler) layers. Our
calculations suggest that the surplus brightness of the penumbra is a natural
consequence of the Evershed flow, and that magnetic flux tubes about 250 km in
diameter can explain the morphology of sunspot penumbrae.


title: Recurrence relations for powers of q-Fibonacci polynomials

abstract:
  We derive some q-analogs of Euler-Cassini-type identities and of recurrence
formulas for powers of Fibonacci polynomials.


title:
A class of non homogeneous self interacting random processes with
  applications to learning in games and vertex-reinforced random walks

abstract:
  Using an approximation by a set-valued dynamical system, this paper studies a
class of non Markovian and non homogeneous stochastic processes on a finite
state space. It provides an unified approach to simulated annealing type
processes. It permits to study new models of vertex reinforced random walks and
new models of learning in games including Markovian fictitious play.


title: Inclusive K0SK0S resonance production in ep collisions at HERA

abstract:
  Inclusive K0SK0S production in ep collisions at HERA was studied with the
ZEUS detector using an integrated luminosity of 0.5 fb-1. Enhancements in the
mass spectrum were observed and are attributed to the production of
f2(1270)/a02(1320), f'2(1525) and f0(1710). Masses and widths were obtained
using a fit which takes into account theoretical predictions based on SU(3)
symmetry arguments, and are consistent with the PDG values. The f0(1710) state,
which has a mass consistent with a glueball candidate, was observed with a
statistical significance of 5 standard deviations. However, if this state is
the same as that seen in gamma gamma -> K0SK0S, it is unlikely to be a pure
glueball state.


title:
NLO QCD corrections to Z b anti-b production with massive bottom quarks
  at the Fermilab Tevatron

abstract:
  We calculate the Next-to-Leading Order (NLO) QCD corrections to Z b anti-b
production in hadronic collisions including full bottom-quark mass effects. We
present results for the total cross section and the invariant mass distribution
of the bottom-quark jet pair at the Fermilab Tevatron p anti-p collider. We
perform a detailed comparison with a calculation that considers massless bottom
quarks, as implemented in the Monte Carlo program MCFM. We find that neglecting
bottom-quark mass effects overestimates the total NLO QCD cross section for Z b
anti-b production at the Tevatron by about 7%, independent of the choice of the
renormalization and factorization scales. Moreover, bottom-quark mass effects
can impact the shape of the bottom-quark pair invariant mass distribution, in
particular in the low invariant mass region.


title: Volume Modulus Inflation and the Gravitino Mass Problem

abstract:
  The Hubble constant during the last stages of inflation in a broad class of
models based on the KKLT mechanism should be smaller than the gravitino mass, H
<~ m_{3/2}. We point out that in the models with large volume of
compactification the corresponding constraint typically is even stronger, H <~
m_{3/2}^{3/2}, in Planck units. In order to address this problem, we propose a
class of models with large volume of compactification where inflation may occur
exponentially far away from the present vacuum state. In these models, the
Hubble constant during inflation can be many orders of magnitude greater than
the gravitino mass. We introduce a toy model describing this scenario, and
discuss its strengths and weaknesses.


title:
Cascades, thermalization and eddy viscosity in helical Galerkin
  truncated Euler flows

abstract:
  The dynamics of the truncated Euler equations with helical initial conditions
are studied. Transient energy and helicity cascades leading to Kraichnan
helical absolute equilibrium at small scales are obtained for the first time.
The results of [Cichowlas et al. Phys. Rev. Lett. 95, 264502 (2005)] are
extended to helical flows. Similarities between the turbulent transient
evolution of the ideal (time-reversible) system and viscous helical flows are
found. The observed differences in the behavior of truncated Euler and
(constant viscosity) Navier-Stokes are qualitatively understood using the
concept of eddy viscosity. The large scales of truncated Euler equations are
then shown to follow quantitatively an effective Navier-Stokes dynamics based
on a variable (scale dependent) eddy viscosity.


title:
Electric Field Induced Transformation of Magnetic Domain Structure in
  Magnetoelectric Iron Garnet Films

abstract:
  The room temperature magnetoelectric effect was observed in epitaxial iron
garnet films that appeared as magnetic domain wall motion induced by electric
field. The films grown on gadolinium-gallium garnet substrates with various
crystallographic orientations were examined. The effect was observed in (210)
and (110) films and was not observed in (111) films. Dynamic observation of the
domain wall motion in 400 V voltage pulses gave the value of domain wall
velocity in the range 30-50 m/s. The same velocity was achieved in magnetic
field pulse about 50 Oe.


title:
A note on the existence of standard splittings for conformally
  stationary spacetimes

abstract:
  Let $(M,g)$ be a spacetime which admits a complete timelike conformal Killing
vector field $K$. We prove that $(M,g)$ splits globally as a standard
conformastationary spacetime with respect to $K$ if and only if $(M,g)$ is
distinguishing (and, thus causally continuous). Causal but non-distinguishing
spacetimes with complete stationary vector fields are also exhibited. For the
proof, the recently solved "folk problems" on smoothability of time functions
(moreover, the existence of a {\em temporal} function) are used.


title: Reliability, Sufficiency, and the Decomposition of Proper Scores

abstract:
  Scoring rules are an important tool for evaluating the performance of
probabilistic forecasting schemes. In the binary case, scoring rules (which are
strictly proper) allow for a decomposition into terms related to the resolution
and to the reliability of the forecast. This fact is particularly well known
for the Brier Score. In this paper, this result is extended to forecasts for
finite--valued targets. Both resolution and reliability are shown to have a
positive effect on the score. It is demonstrated that resolution and
reliability are directly related to forecast attributes which are desirable on
grounds independent of the notion of scores. This finding can be considered an
epistemological justification of measuring forecast quality by proper scores. A
link is provided to the original work of DeGroot et al (1982), extending their
concepts of sufficiency and refinement. The relation to the conjectured
sharpness principle of Gneiting et al (2005a) is elucidated.


title:
Observation of vortex formation in an oscillating trapped Bose-Einstein
  condensate

abstract:
  We report on the observation of vortex formation in a Bose-Einstein
condensate of Rb-87 atoms. Vortices are generated by superimposing an
oscillating excitation to the trapping potential introduced by an external
magnetic field. For small amplitudes of the external excitation field we
observe a bending of the cloud axis. Increasing the amplitude we observe
formation of a growing number of vortices in the sample. Shot-to-shot
variations in both vortex number and position within the condensed cloud are
observed, probably due to the intrinsic vortex nucleation dynamics. We discuss
the possible formation of vortices and anti-vortices in the sample as well as
possible mechanisms for vortex nucleation.


title: Bond excitations in the pseudogap phase of the Hubbard Model

abstract:
  Using the dynamical cluster approximation, we calculate the correlation
functions associated with the nearest neighbor bond operator which measure the
z component of the spin exchange in the two-dimensional Hubbard model with $U$
equal to the bandwidth. We find that in the pseudogap region, the local bond
susceptibility diverges at T=0. This shows the existence of degenerate bond
spin excitation and implies quantum criticality and bond order formation when
long range correlations are considered. The strong correlation between
excitations on parallel neighboring bonds suggests bond singlet dimerization.
The suppression of divergence for $n< \approx 0.78$ implies that tor these
model parameters this is quantum critical point which separates the
unconventional pseudogap region characterized by bond order from a conventional
Fermi liquid.


title:
Evidence for two distinct scales of current flow in polycrystalline Sm
  and Nd iron oxypnictides

abstract:
  Early studies have found quasi-reversible magnetization curves in
polycrystalline bulk rare-earth iron oxypnictides that suggest either
wide-spread obstacles to intergranular current or very weak vortex pinning. In
the present study of polycrystalline samarium and neodymium rare-earth iron
oxypnictide samples made by high pressure synthesis, the hysteretic
magnetization is significantly enhanced. Magneto optical imaging and study of
the field dependence of the remanent magnetization as a function of particle
size both show that global currents over the whole sample do exist but that the
intergranular and intragranular current densities have distinctively different
temperature dependences and differ in magnitude by about 1000. Assuming that
the highest current density loops are restricted to circulation only within
grains leads to values of ~5 MA/cm2 at 5 K and self field, while whole-sample
current densities, though two orders of magnitude lower are 1000-10000 A/cm2,
some two orders of magnitude higher than in random polycrystalline cuprates. We
cannot yet be certain whether this large difference in global and intragrain
current density is intrinsic to the oxypnictides or due to extrinsic barriers
to current flow, because the samples contain significant second phase, some of
which wets the grain boundaries and produces evidences of SNS proximity effect
in the whole sample critical current.


title: Algebraic coarsening in voter models with intermediate states

abstract:
  The introduction of intermediate states in the dynamics of the voter model
modifies the ordering process and restores an effective surface tension. The
logarithmic coarsening of the conventional voter model in two dimensions is
eliminated in favour of an algebraic decay of the density of interfaces with
time, compatible with Model A dynamics at low temperatures. This phenomenon is
addressed by deriving Langevin equations for the dynamics of appropriately
defined continuous fields. These equations are analyzed using field theoretical
arguments and by means of a recently proposed numerical technique for the
integration of stochastic equations with multiplicative noise. We find good
agreement with lattice simulations of the microscopic model.


title:
Nonlocal chiral quark models with wavefunction renormalization: sigma
  properties and \pi-\pi scattering parameters

abstract:
  We analyze the sigma meson mass and width together with the pion-pion
scattering parameters in the context of non-local chiral quark models with
wave-function renormalization (WFR). We consider both non-local interactions
based on the frequently used exponential form factor, and on fits to the mass
and renormalization functions obtained in lattice calculations. In the case of
the sigma properties we obtain results which are less dependent on the
parameterization than in the standard local NJL model, and which are in
reasonable agreement with the recently reported empirical values. We also show
that the inclusion of the WFR tend to improve the description of the $\pi-\pi$
scattering parameters, with the lattice inspired parameterization providing the
best overall results. Finally, we analyze the connection of the non-local quark
models discussed here with Chiral Perturbation Theory, and present the model
predictions for the low energy constants relevant for $\pi-\pi$ scattering to
O(4) in the chiral expansion.


title:
Planet formation in Alpha Centauri A revisited: not so
  accretion-friendly after all

abstract:
  We numerically explore planet formation around alpha Cen A by focusing on the
crucial planetesimals-to-embryos phase. Our code computes the relative velocity
distribution, and thus the accretion vs. fragmentation trend, of planetesimal
populations having any given size distribution. This is a critical aspect of
planet formation in binaries since the pericenter alignment of planetesimal
orbits due to the gravitational perturbations of the companion star and to gas
friction strongly depends on size. We find that, for the nominal case of a MMSN
gas disc, the region beyond 0.5AU from the primary is hostile to planetesimal
accretion. In this area, impact velocities between different-size bodies are
increased, by the differential orbital phasing, to values too high to allow
mutual accretion. For any realistic size distribution for the planetesimal
population, this accretion-inhibiting effect is the dominant collision outcome
and the accretion process is halted. Results are robust with respect to the
profile and density of the gas disc: except for an unrealistic almost gas-free
case, the inner accretion safe area never extends beyond 0.75AU. We conclude
that planet formation is very difficult in the terrestrial region around alpha
Cen A, unless it started from fast-formed very large (>30km) planetesimals.
Notwithstanding these unlikely initial conditions, the only possible
explanation for the presence of planets around 1 AU from the star would be the
hypothetical outward migration of planets formed closer to the star or a
different orbital configuration in the binary's early history. Our conclusions
differ from those of several studies focusing on the later embryos-to-planets
stage, confirming that the planetesimals-to-embryos phase is more affected by
binary perturbations.


title:
The time variation of the fine structure constant: A statistical
  analysis of astronomical data

abstract:
  We analyze different data of the variation of the fine structure constant
obtained with different methods to check their consistency.We test consistency
using the modified Student test and confidence intervals. We split the data
sets in smaller intervals. A criterion for this selection is proposed. Results
show consistency for reduced intervals for each pair of data sets considered.
Results are at variance with the ones obtained considering mean values over the
whole interval.


title: Formation of deeply bound molecules via chainwise adiabatic passage

abstract:
  We suggest and analyze a novel technique for efficient and robust creation of
dense ultracold molecular ensembles in their ground rovibrational state. In our
approach a molecule is brought to the ground state through a series of
intermediate vibrational states via a {\em multistate chainwise Stimulated
Raman Adiabatic Passage} (c-STIRAP) technique. We study the influence of the
intermediate states decay on the transfer process and suggest an approach that
minimizes the population of these states, resulting in a maximal transfer
efficiency. As an example, we analyze the formation of $^{87}$Rb$_{2}$ starting
from an initial Feshbach molecular state and taking into account major decay
mechanisms due to inelastic atom-molecule and molecule-molecule collisions.
Numerical analysis suggests a transfer efficiency $>$ 90%, even in the presence
of strong collisional relaxation as are present in a high density atomic gas.


title: Lipid thermodynamics : melting is molecular

abstract:
  This computational experiment demonstrates that chain melting in lipids is a
molecular process. BOMD is certainly the best method to reproduce such dynamics
properties, since the electronic contributions to the various molecular
structures sampled by the classical nuclear dynamics are described accurately.


title:
3D-Chiral Metamaterial Showing Artificial Magnetic Response and Negative
  Refraction

abstract:
  Artificial magnetism, negative permeability and negative refractive index are
demonstrated in 3D-chiral metamaterial that shows giant polarization rotation
and circular dichroism.


title:
Constraints on the Properties of the Neutron Star XTE J1814-338 from
  Pulse Shape Models

abstract:
  The accretion-powered (non-X-ray burst) pulsations of XTE J1814-338 are
modeled to determine neutron star parameters and their uncertainties. The model
is a rotating circular hot spot and includes: (1) an isotropic blackbody
spectral component; (2) an anisotropic Comptonized spectral component; (3)
relativistic time-delays and light-bending; and (4) the oblate shape of the
star due to rotation. This model is the simplest possible model that is
consistent with the data. The resulting best-fit parameters of the model favor
stiff equations of state, as can be seen from the 3-sigma allowed regions in
the mass-radius diagram. We analyzed all data combined from a 23 day period of
the 2003 outburst, and separately analyzed data from 2 days of the outburst.
The allowed mass-radius regions for both cases only allow equations of state
(EOS) that are stiffer than EOS APR (Akmal et al. 1998), consistent with the
large mass that has been inferred for the pulsar NGC 6440B (Freire et al.
2008). The stiff EOS inferred by this analysis is not compatible with the soft
EOS inferred from a similar analysis of SAX J1808.


title: W/Z + Jets and W/Z + Heavy Flavor Jets at the Tevatron

abstract:
  Studies of the production of W/Z + jets are important for a variety of
reasons. W/Z + inclusive jets is a valuable high statistics sample that allows
one to probe the validity of predictions from perturbative Quantum
Chromodynamics (pQCD) at both leading and next-to-leading order. W/Z + heavy
flavor jets (those originating from b or c production) is a significant
background to top and Higgs at the Tevatron and will play an important role at
the LHC as well. Herein the latest Tevatron results on these production
mechanisms are reviewed with an emphasis on comparison of data results to the
latest theoretical models.


title:
Diamagnetic persistent currents for electrons in ballistic billiards
  subject to a point flux

abstract:
  We study the persistent current of noninteracting electrons subject to a
pointlike magnetic flux in the simply connected chaotic Robnik-Berry quantum
billiard, and also in an annular analog thereof. For the simply connected
billiard we find a large diamagnetic contribution to the persistent current at
small flux, which is independent of the flux and is proportional to the number
of electrons (or equivalently the density since we keep the area fixed). The
size of this diamagnetic contribution is much larger than mesoscopic
fluctuations in the persistent current in the simply connected billiard, and
can ultimately be traced to the response of the angular momentum $l=0$ levels
(neglected in semiclassical expansions) on the unit disk to a pointlike flux at
its center. The same behavior is observed for the annular billiard when the
inner radius is much smaller than the outer one, while the usual fluctuating
persistent current and Anderson-like localization due to boundary scattering
are seen when the annulus tends to a one-dimensional ring. We explore the
conditions for the observability of this phenomenon.


title: Hilbert C*-modules and spectral analysis of many-body systems

abstract:
  We study the spectral properties of a class of many channel Hamiltonians
which contains those of systems of particles interacting through k-body and
field type forces which do not preserve the number of particles. Our results
concern the essential spectrum, the Mourre estimate, and the absence of
singular continuous spectrum. The appropriate formalism involves graded
C*-algebras and Hilbert C*-modules as basic tools.


title:
Evidence for Supercurrent Connectivity in Conglomerate Particles in
  NdFeAsO1-d

abstract:
  Here we use global and local magnetometry and Hall probe imaging to
investigate the electromagnetic connectivity of the superconducting current
path in the oxygen-deficient fluorine-free Nd-based oxypnictides. High
resolution transmission electron microscopy and scanning electron microscopy
show strongly-layered crystallites, evidence for a ~ 5nm amorphous oxide around
individual particles, and second phase neodymium oxide which may be responsible
for the large paramagnetic background at high field and at high temperatures.
  From global magnetometry and electrical transport measurements it is clear
that there is a small supercurrent flowing on macroscopic sample dimensions
(mm), with a lower bound for the average (over this length scale) critical
current density of the order of 103 A/cm2. From magnetometry of powder samples
and local Hall probe imaging of a single large conglomerate particle ~120
microns it is clear that on smaller scales, there is better current
connectivity with a critical current density of the order of 5 x 104 A/cm2. We
find enhanced flux creep around the second peak anomaly in the magnetisation
curve and an irreversibility line significantly below Hc2(T) as determined by
ac calorimetry.