title: Toward a Proof of Montonen-Olive Duality via Multiple M2-branes

abstract:
  We derive 4-dimensional N=4 U(N) supersymmetric Yang-Mills theory from a
3-dimensional Chern-Simons-matter theory with product gauge group U(N)^{2n}.
The latter describes M2-branes probing an orbifold where a torus emerges in a
scaling limit. It is expected that the SL(2, Z) duality of the 4-dimensional
Yang-Mills theory will be shown in M-theory point of view since it is trivially
realized as modular transformations of the torus. Indeed, starting from one
single Chern-Simons-matter theory, we find infinitely many equivalent
4-dimensional theories differing up to T-transformation of the SL(2, Z)
redefinition of the gauge coupling tau=theta/2pi + 4pi i/g^2 and a parity
transformation in 4 dimensions. Although S-transformation can not be shown in
our work, it is important that a part of the SL(2, Z) transformation is
realized via the M2-brane action. Thus we think our work can be a step toward a
proof of Montonen-Olive duality via M2-branes.


title: Hall-Littlewood plane partitions and KP

abstract:
  MacMahon's classic generating function of random plane partitions, which is
related to Schur polynomials, was recently extended by Vuletic to a generating
function of weighted plane partitions that is related to Hall-Littlewood
polynomials, S(t), and further to one related to Macdonald polynomials, S(t,q).
  Using Jing's 1-parameter deformation of charged free fermions, we obtain a
Fock space derivation of the Hall-Littlewood extension. Confining the plane
partitions to a finite s-by-s square base, we show that the resulting
generating function, S_{s-by-s}(t), is an evaluation of a tau-function of KP.


title: Constructing the Primitive Roots of Prime Powers

abstract:
  We use only addition and multiplication to construct the primitive roots of
$p^{k+1}$ from the primitive roots of $p^{k}$, where $p$ is an odd prime and
$k$ is at least 2.


title: Ionization Cone in the X-ray Binary LMC X-1

abstract:
  In an earlier paper, we presented the first evidence for a bow-shock nebula
surrounding the X-ray binary LMC X-1 on a scale of ~15 pc, which we argued was
powered by a jet associated with an accretion disk. We now present the first
evidence for an ionization cone extending from an X-ray binary, a phenomenon
only seen to date in active galactic nuclei (AGN). The ionization cone,
detected in the HeII4686/Hbeta and [OIII]5007/Hbeta line ratio maps, aligns
with the direction of the jet inferred from the bow-shock nebula. The cone has
an opening angle ~45 deg and radial extent ~3.8 pc. Since the HeII emission
cannot be explained by the companion O star, the gas in the ionization cone
must be exposed to the `naked' accretion disk, thereby allowing us to place
constraints on the unobservable ionizing spectrum. The energetics of the
ionization cone give unambiguous evidence for an "ultraviolet - soft X-ray"
(XUV) excess in LMC X-1. Any attempt to match the hard X-ray spectrum (>1keV)
with a conventional model of the accretion disk fails to account for this XUV
component. We propose two likely sources for the observed anisotropy: (1)
obscuration by a dusty torus, or (2) a jet-blown hole in a surrounding envelope
of circumstellar absorbing material. We discuss the implications of our
discovery in the context of the mass-scaling hypothesis for accretion onto
black holes and suggest avenues for future research.


title:
Dispersion relation of an electromagnetic wave in unmagnetized cold
  plasma

abstract:
  The dispersion relation of an electromagnetic wave in an unmagnetized neutral
plasma is well known to be w^2=wp^2+(ck)^2. A modified dispersion relation is
presented taking into account the ion restoring force in the transverse
direction.


title: The dyonic picture of topological objects in the deconfined phase

abstract:
  In the deconfinement phase of quenched SU(2) Yang-Mills theory the spectrum
and localization properties of the eigenmodes of the overlap Dirac operator
with antiperiodic boundary conditions are strongly dependent on the sign of the
average Polyakov loop, $<L>$. For $<L> > 0$ a gap appears with only few, highly
localized topological zero and near-zero modes separated from the rest of the
spectrum. Instead of a gap, for $<L> < 0$ a high spectral density of relatively
delocalized near-zero modes is observed. In an ensemble of positive $<L>$, the
same difference of the spectrum appears under a change of fermionic boundary
conditions. We argue that this effect and other properties of near-zero modes
can be explained through the asymmetric properties and the different abundance
of dyons and antidyons -- topological objects also known to appear, however in
a symmetric form, in the confinement phase at $T < T_c$ as constituents of
calorons with maximally nontrivial holonomy.


title: Combinatorics and geometry of power ideals

abstract:
  We investigate ideals in a polynomial ring which are generated by powers of
linear forms. Such ideals are closely related to the theories of fat point
ideals, Cox rings, and box splines.
  We pay special attention to a family of power ideals that arises naturally
from a hyperplane arrangement A. We prove that their Hilbert series are
determined by the combinatorics of A, and can be computed from its Tutte
polynomial. We also obtain formulas for the Hilbert series of the resulting fat
point ideals and zonotopal Cox rings.
  Our work unifies and generalizes results due to Dahmen-Micchelli, Holtz-Ron,
Postnikov-Shapiro-Shapiro, and Sturmfels-Xu, among others. It also settles a
conjecture of Holtz-Ron on the spline interpolation of functions on the
interior lattice points of a zonotope.


title: Shell-model calculations and realistic effective interactions

abstract:
  A review is presented of the development and current status of nuclear
shell-model calculations in which the two-body effective interaction is derived
from the free nucleon-nucleon potential. The significant progress made in this
field within the last decade is emphasized, in particular as regards the
so-called V-low-k approach to the renormalization of the bare nucleon-nucleon
interaction. In the last part of the review we first give a survey of realistic
shell-model calculations from early to present days. Then, we report recent
results for neutron-rich nuclei near doubly magic 132Sn and for the whole
even-mass N=82 isotonic chain. These illustrate how shell-model effective
interactions derived from modern nucleon-nucleon potentials are able to provide
an accurate description of nuclear structure properties.


title: Bragg spectroscopy of a strongly interacting Fermi gas

abstract:
  We present a comprehensive study of the Bose-Einstein condensate to
Bardeen-Cooper-Schrieffer (BEC-BCS) crossover in fermionic $^6$Li using Bragg
spectroscopy. A smooth transition from molecular to atomic spectra is observed
with a clear signature of pairing at and above unitarity. These spectra probe
the dynamic and static structure factors of the gas and provide a direct link
to two-body correlations. We have characterised these correlations and measured
their density dependence across the broad Feshbach resonance at 834 G.


title: The Case for Hypercritical Accretion in M33 X-7

abstract:
  The spin parameter of the black hole in M33 X-7 has recently been measured to
be a*=0.77+-0.05 (Liu et al. 2008). It has been proposed that the spin of the
15.65 M_sun black hole is natal. We show that this is not a viable evolutionary
path given the observed binary orbital period of 3.45 days since the explosion
that would produce a black hole with the cited spin parameter and orbital
period would disrupt the binary. Furthermore, we show that the system has to be
evolved through the hypercritical mass transfer of about 5 M_sun from the
secondary star to the black hole.


title:
Investigation on Multiuser Diversity in Spectrum Sharing Based Cognitive
  Radio Networks

abstract:
  A new form of multiuser diversity, named \emph{multiuser interference
diversity}, is investigated for opportunistic communications in cognitive radio
(CR) networks by exploiting the mutual interference between the CR and the
existing primary radio (PR) links. The multiuser diversity gain and ergodic
throughput are analyzed for different types of CR networks and compared against
those in the conventional networks without the PR link.


title:
Cognitive Beamforming Made Practical: Effective Interference Channel and
  Learning-Throughput Tradeoff

abstract:
  This paper studies the transmit strategy for a secondary link or the
so-called cognitive radio (CR) link under opportunistic spectrum sharing with
an existing primary radio (PR) link. It is assumed that the CR transmitter is
equipped with multi-antennas, whereby transmit precoding and power control can
be jointly deployed to balance between avoiding interference at the PR
terminals and optimizing performance of the CR link. This operation is named as
cognitive beamforming (CB). Unlike prior study on CB that assumes perfect
knowledge of the channels over which the CR transmitter interferes with the PR
terminals, this paper proposes a practical CB scheme utilizing a new idea of
effective interference channel (EIC), which can be efficiently estimated at the
CR transmitter from its observed PR signals. Somehow surprisingly, this paper
shows that the learning-based CB scheme with the EIC improves the CR channel
capacity against the conventional scheme even with the exact CR-to-PR channel
knowledge, when the PR link is equipped with multi-antennas but only
communicates over a subspace of the total available spatial dimensions.
Moreover, this paper presents algorithms for the CR to estimate the EIC over a
finite learning time. Due to channel estimation errors, the proposed CB scheme
causes leakage interference at the PR terminals, which leads to an interesting
learning-throughput tradeoff phenomenon for the CR, pertinent to its time
allocation between channel learning and data transmission. This paper derives
the optimal channel learning time to maximize the effective throughput of the
CR link, subject to the CR transmit power constraint and the interference power
constraints for the PR terminals.


title: Evaluation of mutual information estimators on nonlinear dynamic systems

abstract:
  Mutual information is a nonlinear measure used in time series analysis in
order to measure the linear and non-linear correlations at any lag $\tau$. The
aim of this study is to evaluate some of the most commonly used mutual
information estimators, i.e. estimators based on histograms (with fixed or
adaptive bin size), $k$-nearest neighbors and kernels. We assess the accuracy
of the estimators by Monte-Carlo simulations on time series from nonlinear
dynamical systems of varying complexity. As the true mutual information is
generally unknown, we investigate the existence and rate of consistency of the
estimators (convergence to a stable value with the increase of time series
length), and the degree of deviation among the estimators. The results show
that the $k$-nearest neighbor estimator is the most stable and less affected by
the method-specific parameter.


title:
The stability of an optical clock laser transferred to the interrogation
  oscillator for a Cs fountain

abstract:
  We stabilise a microwave oscillator at 9.6 GHz to an optical clock laser at
344 THz by using a fibre-based femtosecond laser frequency comb as a transfer
oscillator. With a second frequency comb we measure independently the
instability of the microwave source with respect to another optical clock laser
frequency at 456 THz. The total fractional frequency instability of this
optic-to-microwave and microwave-to-optic conversion resulted in an Allan
deviation sigma_y, of sigma_y=1.2E-14 at 1 s averaging time (band width 50
kHz). The residual phase noise density is -97 dBc/Hz at 10 Hz offset from the
9.6 GHz carrier. Replacing the existing quartz-based interrogation oscillator
of the PTB caesium fountain CSF1 with this optically stabilised microwave
source will reduce the instability contribution due to the Dick effect from the
1E-13-level at 1s averaging time to an insignificant level at the current
status of CSF1. Therefore this new microwave source can be an alternative to
cryogenic sapphire-loaded cavity oscillators in order to overcome the
limitations of state-of-the-art quartz oscillators.


title: Flares in Gamma Ray Bursts (II)

abstract:
  We illustrate some of the preliminary results obtained with a new sample of
flares and a new analysis. In these proceedings we deal mainly with the
analysis related to the flare energy and describe the work in progress to
measure the average flare luminosity curve. We discuss in brief GRB050904 and
GRB050724 for matters relevant to this work. In particular we measure the
contribution given to the flares by GRB050904 and give a new interpretation for
the decaying early XRT light curve of GRB050724. We briefly illustrate the
first evidence that the early decay is given by the subsequent emission of
events with Width/TPeak < 1 and the total energy of these events is larger than
the energy emitted during the prompt emission spike showing, indeed, that not
only the central engine may still be active after hundreds of seconds of the
first spike but that this may still be part of the prompt emission.


title: Informed Network Coding for Minimum Decoding Delay

abstract:
  Network coding is a highly efficient data dissemination mechanism for
wireless networks. Since network coded information can only be recovered after
delivering a sufficient number of coded packets, the resulting decoding delay
can become problematic for delay-sensitive applications such as real-time media
streaming. Motivated by this observation, we consider several algorithms that
minimize the decoding delay and analyze their performance by means of
simulation. The algorithms differ both in the required information about the
state of the neighbors' buffers and in the way this knowledge is used to decide
which packets to combine through coding operations. Our results show that a
greedy algorithm, whose encodings maximize the number of nodes at which a coded
packet is immediately decodable significantly outperforms existing network
coding protocols.


title:
Study of psi' and chi_c decays as feed-down sources of J/psi
  hadro-production

abstract:
  The interpretation of the J/psi suppression patterns observed in nuclear
collisions, at CERN and RHIC, as a signature of the formation of a deconfined
phase of QCD matter, requires knowing which fractions of the measured J/psi
yields, in pp collisions, are due to decays of heavier charmonium states. From
a detailed analysis of the available mid-rapidity charmonium hadro-production
cross sections, or their ratios, we determine that the J/psi feed-down
contributions from psi' and chi_c decays are, respectively, (8.1 +/- 0.3) % and
(25 +/- 5) %. These proton-proton values are derived from global averages of
the proton-nucleus measurements, assuming that the charmonium states are
exponentially absorbed with the length of matter they traverse in the nuclear
targets.


title: 't Hooft tensor for generic gauge group

abstract:
  We study monopoles in gauge theories with generic gauge group. Magnetic
charges are in one-to-one correspondence with the second homotopy classes at
spatial infinity (${\Pi}_2$), which are therefore identified by the 't Hooft
tensor. We determine the 't Hooft tensor in the general case. These issues are
relevant to the understanding of Color Confinement.


title: Hyperentanglement witness

abstract:
  A new criterium to detect the entanglement present in a {\it hyperentangled
state}, based on the evaluation of an entanglement witness, is presented. We
show how some witnesses recently introduced for graph states, measured by only
two local settings, can be used in this case. We also define a new witness
$W_3$ that improves the resistance to noise by increasing the number of local
measurements.


title:
Combined Effects of Galaxy Interactions and Large-Scale Environment on
  Galaxy Properties

abstract:
  We inspect the coupled dependence of physical parameters of the SDSS galaxies
on the small-scale (distance to and morphology of the nearest neighbor galaxy)
and the large-scale (background density smoothed over 20 nearby galaxies)
environments. The impacts of interaction on galaxy properties are detected at
least out to the neighbor separation corresponding to the virial radius of
galaxies, which is typically between 200 and 400 h^{-1}kpc for the galaxies in
our sample. To detect these long-range interaction effects it is crucial to
divide galaxy interactions into four cases dividing the morphology of target
and neighbor galaxies into early and late types. We show that there are two
characteristic neighbor-separation scales where the galaxy interactions cause
abrupt changes in the properties of galaxies. The first scale is the virial
radius of the nearest neighbor galaxy r_{vir,nei}. Many physical parameters
start to deviate from those of extremely isolated galaxies at the projected
neighbor separation r_p of about r_{vir,nei}. The second scale is at r_p
\approx 0.05 r_{vir,nei} = 10--20 h^{-1} kpc, and is the scale at which the
galaxies in pairs start to merge. We find that late-type neighbors enhance the
star formation activity of galaxies while early-type neighbors reduce it, and
that these effects occur within r_{vir,nei}. The hot halo gas and cold disk gas
must be participating in the interactions at separations less than the virial
radius of the galaxy plus dark halo system. Our results also show that the role
of the large-scale density in determining galaxy properties is minimal once
luminosity and morphology are fixed. We propose that the weak residual
dependence of galaxy properties on the large-scale density is due to the
dependence of the halo gas property on the large-scale density.


title: Q2237+0305 in X-rays: spectra and variability with XMM-Newton

abstract:
  X-ray observations of gravitationally lensed quasars may allow us to probe
the inner structure of the central engine of a quasar. Observations of
Q2237+0305 (Einstein Cross) in X-rays may be used to constrain the inner
structure of the X-ray emitting source. Here we analyze the XMM-Newton
observation of the quasar in the gravitational lens system Q2237+0305 taken
during 2002. Combined spectra of the four images of the quasar in this system
were extracted and modelled with a power-law model. Statistical analysis was
used to test the variability of the total flux. The total X-ray flux from all
the images of this quadruple gravitational lens system is 6 x 10^{-13}
erg/cm2/s in the range 0.2-10 keV, showing no significant X-ray spectral
variability during almost 42 ks of the observation time. Fitting of the cleaned
source spectrum yields a photon power-law index of Gamma=1.82+0.07/-0.08. The
X-ray lightcurves obtained after background subtraction are compatible with the
hypothesis of a stationary flux from the source.


title: Compactness properties of operator multipliers

abstract:
  We continue the study of multidimensional operator multipliers initiated in
[arXiv:math/0701645]. We introduce the notion of the symbol of an operator
multiplier. We characterise completely compact operator multipliers in terms of
their symbol as well as in terms of approximation by finite rank multipliers.
We give sufficient conditions for the sets of compact and completely compact
multipliers to coincide and characterise the cases where an operator multiplier
in the minimal tensor product of two C*-algebras is automatically compact. We
give a description of multilinear modular completely compact completely bounded
maps defined on the direct product of finitely many copies of the C*-algebra of
compact operators in terms of tensor products, generalising results of Saar.


title: On the X-ray feature associated with the Guitar Nebula

abstract:
  Context: A mysterious X-ray nebula, showing a remarkably linear geometry, was
recently discovered close to the Guitar Nebula, the bow-shock nebula associated
with B2224+65, which is the fastest pulsar known. The nature of this X-ray
feature is unknown, and even its association with pulsar B2224+65 is unclear.
Aims: We attempt to develop a self-consistent scenario to explain the complex
phenomenology of this object. Methods: We assume that the highest energy
electrons accelerated at the termination shock escape from the bow shock and
diffuse into the ambient medium, where they emit synchrotron X-rays. The linear
geometry should reflect the plane-parallel geometry of its ambient field.
Results: We estimate the Lorentz factor of the X-ray emitting electrons and the
strength of the magnetic field. The former (~10^8) is close to its maximum
possible value, while the latter, at ~45 uG, is higher than typical
interstellar values and must have been amplified in some way. The magnetic
field must also be turbulent to some degree to trap the electrons sufficiently
for synchrotron X-ray emission to occur effectively. We propose a
self-consistent scenario in which, by some streaming instability, the electrons
themselves generate a turbulent field in which they then diffuse. Some
numerical coincidences are explained, and tests are proposed to verify our
scenario. Conclusions: Electron leaking may be common in the majority of pulsar
bow-shock nebulae, even though the X-ray nebulosity in general is too diffuse
to be detectable.


title: Moving curves and Seshadri constants

abstract:
  We study families of curves covering a projective surface and give lower
bounds on the self-intersection of the members of such families, improving
results of Ein-Lazarsfeld and Xu. We apply the obtained inequalities to get new
insights on Seshadri constants and geometry of surfaces.


title: Higher dimensional algebras via colored PROPs

abstract:
  Starting from any unital colored PROP $P$, we define a category $P(P)$ of
shapes called $P$-propertopes. Presheaves on $P(P)$ are called $P$-propertopic
sets. For $0 \leq n \leq \infty$ we define and study $n$-time categorified
$P$-algebras as $P$-propertopic sets with some lifting properties. Taking
appropriate PROPs $P$, we obtain higher categorical versions of polycategories,
2-fold monoidal categories, topological quantum field theories, and so on.


title:
Correlations of projectile like fragments in heavy ion reactions at
  Fermi energy

abstract:
  Correlations between pairs of projectile-like fragments, emitted by the
system ${^{16}O}+{^{197}Au}$ at the laboratory bombarding energy of 515 MeV,
have been studied under two stipulated conditions: (1) at least one member of
the pair is emitted at an angle less than the grazing angle for the system, (2)
both the members of the pair are emitted at angles larger than the grazing
angle. A surprisingly large difference, by more than an order of magnitude, is
found between the correlations for the two cases. This observation could be
explained on the basis of a simple semi-classical break up model. Further
analysis of the variation of the charge correlation function with the
difference in the nuclear charges of the correlated pair showed trends which
are consistent with an "inelastic break up process", in which the projectile
breaks up at the radius of contact, in such a way that, one fragment
(preferably the lighter) is emitted to one side within the grazing angle, while
the other orbits around the target nucleus for a while and emerges on the other
side, at a negative scattering angle, much like in a deep inelastic scattering.


title: Isoscaling as a measure of Symmetry Energy in the Lattice Gas Model

abstract:
  The energetic properties of nuclear clusters inside a low-density,
finite-temperature medium are studied with a Lattice Gas Model including
isospin dependence and Coulomb forces. Important deviations are observed
respect to the Fisher approximation of an ideal gas of non-interacting
clusters, but the global energetics can still be approximately expressed in
terms of a simple modified energy-density functional. The multi-fragmentation
regime appears dominated by combinatorial effects in this model, but the
isoscaling of the largest fragment in low energy collisions appears a promising
observable for the experimental measurement of the symmetry energy.


title: Crumpling wires in two dimensions

abstract:
  An energy-minimal simulation is proposed to study the patterns and mechanical
properties of elastically crumpled wires in two dimensions. We varied the
bending rigidity and stretching modulus to measure the energy allocation,
size-mass exponent, and the stiffness exponent. The mass exponent is shown to
be universal at value $D_{M}=1.33$. We also found that the stiffness exponent
$\alpha =-0.25$ is universal, but varies with the plasticity parameters $s$ and
$\theta_{p}$. These numerical findings agree excellently with the experimental
results.


title: Thermostats, chaos and Onsager reciprocity

abstract:
  Finite thermostats are studied in the context of nonequilibrium statistical
mechanics. Entropy production rate has been identified with the mechanical
quantity expressed by the phase space contraction rate and the currents have
been linked to its derivatives with respect to the parameters measuring the
forcing intensities. In some instances Green-Kubo formulae, hence Onsager
reciprocity, have been related to the fluctuation theorem. However, mainly when
dissipation takes place at the boundary (as in gases or liquids in contact with
thermostats), phase space contraction may be independent on some of the forcing
parameters or, even in absence of forcing, phase space contraction may not
vanish: then the relation with the fluctuation theorem does not seem to apply.
On the other hand phase space contraction can be altered by changing the metric
on phase space: here this ambiguity is discussed and employed to show that the
relation between the fluctuation theorem and Green-Kubo formulae can be
extended and is, by far, more general.


title: On the descending central sequence of absolute Galois groups

abstract:
  Let $p$ be an odd prime number and $F$ a field containing a primitive $p$th
root of unity. We prove a new restriction on the group-theoretic structure of
the absolute Galois group $G_F$ of $F$. Namely, the third subgroup $G_F^{(3)}$
in the descending $p$-central sequence of $G_F$ is the intersection of all open
normal subgroups $N$ such that $G_F/N$ is 1, $\mathbb{Z}/p^2$, or the modular
group $M_{p^3}$ of order $p^3$.


title:
The moduli space of germs of generic families of analytic
  diffeomorphisms unfolding a parabolic fixed point

abstract:
  In this paper we describe the moduli space of germs of generic families of
analytic diffeomorphisms which unfold a parabolic fixed point of codimension 1.
  In [MRR] (and also [R]), it was shown that the Ecalle-Voronin modulus can be
unfolded to give a complete modulus for such germs. The modulus is defined on a
ramified sector in the canonical perturbation parameter $\eps$. As in the case
of the Ecalle-Voronin modulus, the modulus is defined up to a linear scaling
depending only on $\eps$.
  Here, we characterize the moduli space for such unfoldings by finding the
compatibility conditions on the modulus which are necessary and sufficient for
realization as the modulus of an unfolding.
  The compatibility condition is obtained by considering the region of
sectorial overlap in $\eps$-space. This lies in the Glutsyuk sector where the
two fixed points are hyperbolic and connected by the orbits of the
diffeomorphism. In this region we have two representatives of the modulus which
describe the same dynamics. We identify the necessary compatibility condition
between these two representatives by comparing them both with their common
Glutsyuk modulus.
  The compatibility condition implies the existence of a linear scaling for
which the modulus is 1/2-summable in $\eps$, whose direction of non-summability
coincides with the direction of real multipliers at the fixed points.
Conversely, we show that the compatibility condition (which implies the
summability property) is sufficient to realize the modulus as coming from an
analytic unfolding, thus giving a complete description of the space of moduli.


title: Fairness in Combinatorial Auctioning Systems

abstract:
  One of the Multi-Agent Systems that is widely used by various government
agencies, buyers and sellers in a market economy, in such a manner so as to
attain optimized resource allocation, is the Combinatorial Auctioning System
(CAS). We study another important aspect of resource allocations in CAS, namely
fairness. We present two important notions of fairness in CAS, extended
fairness and basic fairness. We give an algorithm that works by incorporating a
metric to ensure fairness in a CAS that uses the Vickrey-Clark-Groves (VCG)
mechanism, and uses an algorithm of Sandholm to achieve optimality.
Mathematical formulations are given to represent measures of extended fairness
and basic fairness.


title: In Vitro Studies of Cells Grown on the Superconductor PrOxFeAs

abstract:
  The recent discovery of arsenic-based high temperature superconductors has
reignited interest in the study of superconductor : biological interfaces.
However, the new superconductor materials involve the chemistry of arsenic,
their toxicity remain unclear [ Nature, 2008, 452(24):922]. In this study the
possible adverse effects of this new family of superconductors on cells have
been examined. Cell culture studies in conjunction with microscopy and
viability assays were employed to examine the influence of arsenic-based
superconductor PrOxFeAs (x=0.75) material in vitro. Imaging data revealed that
cells were well adhered and spread on the surface of the superconductor.
Furthermore, cytotoxicity studies showed that cells were unaffected during the
time-course of the experiments, providing support for the biocompatibility
aspects of PrOxFeAs-based superconductor material.


title: Absorption features in the spectra of X-ray bursting neutron stars

abstract:
  The discovery of photospheric absorption lines in XMM-Newton spectra of the
X-ray bursting neutron star in EXO0748-676 by Cottam and collaborators allows
us to constrain the neutron star mass-radius ratio from the measured
gravitational redshift. A radius of R=9-12km for a plausible mass range of
M=1.4-1.8Msun was derived by these authors. It has been claimed that the
absorption features stem from gravitationally redshifted (z=0.35) n=2-3 lines
of H- and He-like iron. We investigate this identification and search for
alternatives. We compute LTE and non-LTE neutron-star model atmospheres and
detailed synthetic spectra for a wide range of effective temperatures
(effective temperatures of 1 - 20MK) and different chemical compositions.
  We are unable to confirm the identification of the absorption features in the
X-ray spectrum of EXO0748-676 as n=2-3 lines of H- and He-like iron (Fe XXVI
and Fe XXV). These are subordinate lines that are predicted by our models to be
too weak at any effective temperature. It is more likely that the strongest
feature is from the n=2-3 resonance transition in Fe XXIV with a redshift of
z=0.24. Adopting this value yields a larger neutron star radius, namely
R=12-15km for the mass range M=1.4-1.8Msun, favoring a stiff equation-of-state
and excluding mass-radius relations based on exotic matter. Combined with an
estimate of the stellar radius R>12.5km from the work of Oezel and
collaborators, the z=0.24 value provides a minimum neutron-star mass of
M>1.48Msun, instead of M>1.9Msun, when assuming z=0.35.


title:
Optical spectroscopy of X-ray sources in the Taurus molecular cloud:
  discovery of ten new pre-main sequence stars

abstract:
  We have analyzed optical spectra of 25 X-ray sources identified as potential
new members of the Taurus molecular cloud (TMC), in order to confirm their
membership in this SFR. Fifty-seven candidates were previously selected among
the X-ray sources in the XEST survey, having a 2MASS counterpart compatible
with a PMS star based on color-magnitude and color-color diagrams. We obtained
high-resolution optical spectra for 7 of these candidates with the SARG
spectrograph at the TNG telescope, which were used to search for Li absorption
and to measure the Ha line and the radial and rotational velocities; 18
low-resolution optical spectra obtained with DOLORES for other candidate
members were used for spectral classification, for Ha measurements, and to
assess membership together with IR color-color and color-magnitude diagrams and
additional information from the X-ray data. We found that 3 sources show Li
absorption, with equivalent widths of ~500 mA, broad spectral line profiles,
indicating v sin i ~20-40 km/s, radial velocities consistent with those for
known members, and Ha emission. Two of them are classified as new WTTSs, while
the EW (~ -9 Ang) of the Ha line and its broad asymmetric profile clearly
indicate that the third star (XEST-26-062) is a CTTS. Fourteen sources observed
with DOLORES are M-type stars. Fifteen sources show Ha emission; 6 of them have
spectra that indicate surface gravity lower than in MS stars, and their
de-reddened positions in IR color-magnitude diagrams are consistent with their
derived spectral type and with PMS models at the distance of the TMC. The
K-type star XEST-11-078 is confirmed as a new member from the strength of its
Ha emission line. Overall, we confirm membership to the TMC for 10 out of 25
X-ray sources observed in the optical. Three sources remain uncertain.


title:
Concentration-compactness phenomena in the higher order Liouville's
  equation

abstract:
  We investigate different concentration-compactness phenomena related to the
Q-curvature in arbitrary even dimension. We first treat the case of an open
domain in $R^{2m}$, then that of a closed manifold and, finally, the particular
case of the sphere $S^{2m}$. In all cases we allow the sign of the Q-curvature
to vary, and show that in the case of a closed manifold, contrary to the case
of open domains in $R^{2m}$, concentration phenomena can occur only at points
of positive Q-curvature. As a consequence, on a locally conformally flat
manifold of non-positive Euler characteristic we always have compactness.


title: Top Quark Properties

abstract:
  In this document we present several recent (July 2008) results from studies
of the top quark properties at the CDF and D0 experiments at the Tevatron.
Measurements of several top quark properties, as well as tests of new physics
in the top quark production and decay sectors are presented. In the latter
case, no significant evidence for physics beyond the Standard Model is
uncovered, and the tightest constraints to date are placed on most of the new
physics scenarios investigated.


title: Exterior Differential Systems for Yang-Mills Theories

abstract:
  Exterior differential systems are given, and their Cartan characters
calculated, for Maxwell and SU(2)-Yang-Mills equations in dimensions from three
to six.


title: Current Density Functional Theory for one-dimensional fermions

abstract:
  The frequency-dependent response of a one-dimensional fermion system is
investigated using Current Density Functional Theory (CDFT) within the local
approximation (LDA). DFT-LDA, and in particular CDFT-LDA, reproduces very well
the dispersion of the collective excitations. Unsurprisingly, however, the
approximation fails for details of the dynamic response for large wavevectors.
In particular, we introduce CDFT for the one-dimensional spinless fermion model
with nearest-neighbor interaction, and use CDFT-LDA plus exact (Bethe ansatz)
results for the groundstate energy as function of particle density and boundary
phase to determine the linear response. The successes and failures of this
approach are discussed in detail.


title: Numerical Investigation of the 2D N=2 Wess-Zumino Model

abstract:
  We study lattice formulations of the two-dimensional N=2 Wess-Zumino model
with a cubic superpotential. Discretizations with and without lattice
supersymmetries are compared. We observe that the "Nicolai improvement"
introduces new problems to simulations of the supersymmetric model. With high
statistics we check the degeneracy of bosonic and fermionic masses on the
lattice. Perturbative mass corrections to one-loop order are compared with
continuum extrapolations of our lattice results in the weakly coupled regime.
For intermediate couplings first results of fermionic masses in the continuum
are presented where deviations from the perturbative result are observed.


title:
Modeling of chemical processes in the low pressure capacitive RF
  discharges in a mixture of Ar/C2H2

abstract:
  We study the properties of a capacitive 13.56 MHz discharge properties with a
mixture of Ar/C2H2 taking into account the plasmochemistry and growth of heavy
hydrocarbons. A hybrid model was developed to combine the kinetic description
for electron motion and the fluid approach for negative and positive ions
transport and plasmochemical processes. A significant change of plasma
parameters related to injection of 5.8% portion of acetylene in argon was
observed and analyzed. We found that the electronegativity of the mixture is
about 30%. The densities of negatively and positively charged heavy
hydrocarbons are sufficiently large to be precursors for the formation of
nanoparticles in the discharge volume.


title: Classification of real Bott manifolds

abstract:
  A real Bott manifold is the total space of a sequence of $\R P^1$ bundles
starting with a point, where each $\R P^1$ bundle is projectivization of a
Whitney sum of two real line bundles. A real Bott manifold is a real toric
manifold which admits a flat riemannian metric. An upper triangular $(0,1)$
matrix with zero diagonal entries uniquely determines such a sequence of $\R
P^1$ bundles but different matrices may produce diffeomorphic real Bott
manifolds. In this paper we determine when two such matrices produce
diffeomorphic real Bott manifolds. The argument also proves that any graded
ring isomorphism between the cohomology rings of real Bott manifolds with
$\Z/2$ coefficients is induced by an affine diffeomorphism between the real
Bott manifolds. In particular, this implies the main theorem of \cite{ka-ma08}
which asserts that two real Bott manifolds are diffeomorphic if and only of
their cohomology rings with $\Z/2$ coefficients are isomorphic as graded rings.
We also prove that the decomposition of a real Bott manifold into a product of
indecomposable real Bott manifolds is unique up to permutations of the
indecomposable factors.


title: Energy Loss in Stochastic Abelian Medium

abstract:
  Energy losses of fast charged particles in randomly spatially inhomogeneous
stationary medium are considered. Analytical results for effective dielectric
permittivity are presented.


title:
The two INTEGRAL X-ray transients IGR J17091--3624 and IGR J17098--3628:
  a multi-wavelength long term campaign

abstract:
  IGR J17091-3624 and IGR J17098-3628 are two X-ray transients discovered by
INTEGRAL and classified as possible black hole candidates (BHCs). We present
here the results obtained from the analysis of multi-wavelength data sets
collected by different instruments from 2005 until the end of 2007 on both
sources. IGR J17098-3628 has been regularly detected by INTEGRAL and RXTE over
the entire period of the observational campaign; it was also observed with
pointed observations by XMM and Swift/XRT in 2005 and 2006 and exhibited flux
variations not linked with the change of any particular spectral features. IGR
J17091-3624 was initially in quiescence (after a period of activity between
2003 April and 2004 April) and it was then detected again in outburst in the
XRT field of view during a Swift observation of IGR J17098--3628 on 2007 July
9. The observations during quiescence provide an upper limit to the 0.2-10 keV
luminosity, while the observations in outburst cover the transition from the
hard to the soft state. Moreover, we obtain a refined X-ray position for IGR
J17091-3624 from the Swift/XRT observations during the outburst in 2007. The
new position is inconsistent with the previously proposed radio counterpart. We
identify in VLA archive data a compact radio source consistent with the new
X-ray position and propose it as the radio counterpart of the X-ray transient.


title: Electroweak Gauge-Higgs Unification Scenario

abstract:
  In the gauge-Higgs unification scenario 4D Higgs fields are unified with
gauge fields in higher dimensions. The electroweak model is constructed in the
Randall-Sundrum warped space. The electroweak symmetry is dynamically broken by
the Hosotani mechanism due to the top quark contribution. The Higgs mass is
predicted to be around 50 GeV with the vanishing ZZH and WWH couplings so that
the LEP2 bound for the Higgs mass is evaded.


title: Division polynomials for twisted Edwards curves

abstract:
  This paper presents division polynomials for twisted Edwards curves. Their
chief property is that they characterise the $n$-torsion points of a given
twisted Edwards curve. We also present results concerning the coefficients of
these polynomials, which may aid computation.


title:
Deformation and the Nuclear Matrix Elements of the Neutrinoless Double
  Beta Decay

abstract:
  In this talk I will review the "state of the art" of the calculations of the
nuclear matrix elements (NME) of the neutrinoless double beta decays for the
nuclei 48Ca, 76Ge, 82Se, 124Sn, 128Te, 130Te and 136Xe in the framework of the
Interacting Shell Model (ISM), and compare them with the NME's obtained using
the Quasi-particle RPA approach (QRPA). I will also discuss the effect of the
competition between the pairing and quadrupole correlations in the value of
these NME's. In particular I will show that, as the difference in deformation
between parent and grand daughter grows, the NME's of both the neutrinoless and
the two neutrino modes decrease rapidly.


title: Two insulating phases in compressed Pr1-xCaxMnO3 thin films

abstract:
  The temperature dependent resistivity of two Pr1-xCaxMnO3 (x=0.5 and 0.4)
thin films grown on LaAlO3 has been studied as a function of hydrostatic
pressure (up to 2.5 GPa) and magnetic field (up to 9T). Both samples show a
monotonic decrease in the resistivity with an increase in pressure,
corresponding to a change of -35% at 2.5 GPa. No pressure induced
metal-to-insulator transition was observed in the temperature-dependent
resistivity. The non-trivial interaction between high pressure and magnetic
field reveals that the effect of pressure cannot be simply rescaled to that of
a specific field, as has been reported for the corresponding bulk material. We
propose an interpretation of the data based on phase separation, where two
different insulating phases coexist: the charge ordered phase, which is
sensitive to both magnetic field and pressure, and a second insulating phase
that can be tuned by magnetic field. Such a result demonstrates that phase
separation can be manipulated in thin films by independent application of
magnetic field and/or external pressure.


title:
Quantum spin pump on a finite antiferromagnetic chain through bulk
  states

abstract:
  We studied the possibility of the spin pump in a S=1/2 antiferromagnetic
chain. The spin chain is mapped into a fermion system and bosonization is
utilized to transform the equation of motion to a sine-Gordon equation. The
sine-Gordon equation on a finite chain with different boundary conditions is
solved. Among numerous solutions, the static soliton is compatible with the
original physical system. By varying adiabatically a angle in the phase space
composed of applied electric and magnetic fields, the spin states change
between the Neel state and dimer state and a quantized spin is transported by
the bulk state from one end of the system to the other.


title:
Critical behavior driven by the confining potential in optical lattices
  with ultra-cold fermions?

abstract:
  A recent paper [V. L. Campo et. al., Phys. Rev. Lett. 99, 240403 (2007) has
proposed a two-parameter scaling method to determine the phase diagram of the
fermionic Hubbard model from optical lattice experiments. Motivated by this
proposal, we investigate in more detail, the behavior of the ground-state
energy per site as a function of trap size(L) and confining potential (V(x) =
t(x/L)^alpha) in the one-dimensional case. Using the BALDA-DFT method, we find
signatures of critical behavior as alpha goes to infinity.


title:
Correspondence between Calogero-Moser systems and integrable
  SL(N,$\mathbb{C}$) Euler-Arnold tops

abstract:
  The equivalence between the N-particle Calogero-Moser systems and the
integrable sl(N,$\mathbb{C}$)-tops is shown. New rational and trigonometric
classical Lax operators for these systems are found. Relations with new
solutions of the classical Yang-Baxter equations for sl(N,$\mathbb{C}$) are
discussed. Explicit formulae for N=2,3,4 are presented.


title: Degenerations of pre-Lie algebras

abstract:
  We consider the variety of pre-Lie algebra structures on a given
n-dimensional vector space. The group GL_n(K) acts on it, and we study the
closure of the orbits with respect to the Zariski topology. This leads to the
definition of pre-Lie algebra degenerations. We give fundamental results on
such degenerations, including invariants and necessary degeneration criteria.
We demonstrate the close relationship to Lie algebra degenerations. Finally we
classify all orbit closures in the variety of complex 2-dimensional pre-Lie
algebras.


title:
The Continuous Skolem-Pisot Problem: On the Complexity of Reachability
  for Linear Ordinary Differential Equations

abstract:
  We study decidability and complexity questions related to a continuous
analogue of the Skolem-Pisot problem concerning the zeros and nonnegativity of
a linear recurrent sequence. In particular, we show that the continuous version
of the nonnegativity problem is NP-hard in general and we show that the
presence of a zero is decidable for several subcases, including instances of
depth two or less, although the decidability in general is left open. The
problems may also be stated as reachability problems related to real zeros of
exponential polynomials or solutions to initial value problems of linear
differential equations, which are interesting problems in their own right.


title: Rotating states for trapped bosons in an optical lattice

abstract:
  Rotational states for trapped bosons in an optical lattice are studied in the
framework of the Hubbard model. Critical frequencies are calculated and the
main parameter regimes are identified. Transitions are observed from edge
superfluids to vortex lattices with Mott insulating cores, and subsequently to
lattices of interstitial vortices. The former transition coincides with the
Mott transition. Changes in symmetry of the vortex lattices are observed as a
function of lattice depth. Predictions for experimental signatures are
presented.


title:
Control the high-order harmonics cutoff through the combination of
  chirped laser and static electric field

abstract:
  The high harmonic generation from atoms in the combination of chirped laser
pulse and static field is theoretically investigated. For the first time, we
explore a further physical mechanism of the significant extension of high
harmonic generation cutoff based on three-step model. It is shown that the
cutoff is substantially extended due to the asymmetry of the combined field. If
appropriate parameters are chosen, the cutoff of high harmonic generation can
reach Ip+42Up. Furthermore, an ultrabroad super-continuum spectrum can be
generated. When the phases are properly compensated for, an isolated 9
attosecond pulse can be obtained.


title: Coupled SDW and Superconducting Order in FFLO State of CeCoIn$_5$

abstract:
  The mechanism of incommensurate (IC) spin-density-wave (SDW) order observed
in the Flude-Ferrell-Larkin-Ovchinnikov (FFLO) phase of CeCoIn$_5$ is discussed
on the basis of new mode-coupling scheme among IC-SDW order, two
superconducting orders of FFLO with B$_{1{\rm g}}$ ($d_{x^{2}-y^{2}}$) symmetry
and $\pi$-pairing of odd-parity. Unlike the mode-coupling schemes proposed by
Kenzelmann et al, Sciencexpress, 21 August (2008), that proposed in the present
Letter can offer a simple explanation for why the IC-SDW order is observed only
in FFLO phase and the IC wave vector is rather robust against the magnetic
field.


title:
Optical variability of the ultracool dwarf TVLM 513-46546: evidence for
  inhomogeneous dust clouds

abstract:
  We present multi-colour photometry of the M8.5V ultracool dwarf "pulsar" TVLM
513-46546 (hereafter TVLM 513) obtained with the triple-beam photometer
ULTRACAM. Data were obtained simultaneously in the Sloan-g' and Sloan-i' bands.
The previously reported sinusoidal variability, with a period of 2-hrs, is
recovered here. However, the Sloan-g' and Sloan-i' lightcurves are
anti-correlated, a fact which is incompatible with the currently proposed
starspot explanation for the optical variability. The anti-correlated nature
and relative amplitudes of the optical lightcurves are consistent with the
effects of persistent dust clouds rotating on the surface of the star. In the
absence of other plausible explanations for the optical variability of TVLM
513, it seems likely that dust cloud coverage combined with the rapid rotation
of TVLM 513 is responsible for the optical variability in this object. However,
crude modelling of a photosphere with partial dust cloud coverage shows that
the anti-correlation can only be reproduced using cooler models than the
literature temperature of TVLM 513. We suggest this discrepancy can be removed
if more dust is present within the photosphere of TVLM 513 than theoretical
model atmospheres predict, though a definitive statement on this matter will
require the development of self-consistent models of partially dusty
atmospheres.


title:
Arithmetical ranks of Stanley-Reisner ideals of simplicial complexes
  with a cone

abstract:
  When a cone is added to a simplicial complex $\Delta$ over one of its faces,
we investigate the relation between the arithmetical ranks of the
Stanley-Reisner ideals of the original simplicial complex and the new
simplicial complex $\Delta'$. In particular, we show that the arithmetical rank
of the Stanley-Reisner ideal of $\Delta'$ equals the projective dimension of
the Stanley-Reisner ring of $\Delta'$ if the corresponding equality holds for
$\Delta$.


title: Limit law of the local time for Brox's diffusion

abstract:
  We consider Brox's model: a one-dimensional diffusion in a Brownian potential
W. We show that the normalized local time process (L(t;m_(log t) + x)=t; x \in
R), where m_(log t) is the bottom of the deepest valley reached by the process
before time t, behaves asymptotically like a process which only depends on W.
As a consequence, we get the weak convergence of the local time to a functional
of two independent three-dimensional Bessel processes and thus the limit law of
the supremum of the normalized local time. These results are discussed and
compared to the discrete time and space case which same questions have been
solved recently by N. Gantert, Y. Peres and Z. Shi.


title: Imaging of a vibrating object by Sideband Digital Holography

abstract:
  We obtain quantitative measurements of the oscillation amplitude of vibrating
objects by using sideband digital holography. The frequency sidebands on the
light scattered by the object, shifted by n times the vibration frequency, are
selectively detected by heterodyne holography, and images of the object are
calculated for different orders n. Orders up to n=120 have been observed,
allowing the measurement of amplitudes of oscillation that are significantly
larger than the optical wavelength. Using the positions of the zeros of
intensity for each value of n, we reconstruct the shape of vibration the
object.


title: Fermi surface dichotomy on systems with fluctuating order

abstract:
  We investigate the effect of a dynamical collective mode coupled with
quasiparticles at specific wavevectors only. This coupling describes the
incipient tendency to order and produces shadow spectral features at high
energies, while leaving essentially untouched the low energy quasiparticles.
This allows to interpret seemingly contradictory experiments on underdoped
cuprates, where many converging evidences indicate the presence of charge
(stripe or checkerboard) order, which remains instead elusive in the Fermi
surface obtained from angle-resolved photoemission experiments.


title:
The WFI Halpha spectroscopic survey of the Magellanic Clouds: Be stars
  in SMC open clusters

abstract:
  At low metallicity, B-type stars show lower loss of mass and, therefore,
angular momentum so that it is expected that there are more Be stars in the
Magellanic Clouds than in the Milky Way. However, till now, searches for Be
stars were only performed in a very small number of open clusters in the
Magellanic Clouds. Using the ESO/WFI in its slitless spectroscopic mode, we
performed a Halpha survey of the Large and Small Magellanic Cloud. Eight
million low-resolution spectra centered on Halpha were obtained. For their
automatic analysis, we developed the ALBUM code. Here, we present the
observations, the method to exploit the data and first results for 84 open
clusters in the SMC. In particular, cross-correlating our catalogs with OGLE
positional and photometric data, we classified more than 4000 stars and were
able to find the B and Be stars in them. We show the evolution of the rates of
Be stars as functions of area density, metallicity, spectral type, and age.


title:
Proximity effect and its enhancement by ferromagnetism in
  high-temperature superconductor-ferromagnet structures

abstract:
  We consider a bi-layer consisting of a $d-$wave layerd superconductor and
diffusive ferromagnet with a domain wall (DW). The $c-$axis in the
superconductor and DW in the ferromagnet are assumed to be perpendicular to the
interface. We demonstrate that in such a heterostructure the inhomogeneous
exchange field enhances the proximity effect. It is shown that, whereas in the
absence of the exchange field the $d-$wave condensate decays in the normal
metal on the mean free path $l$, the superconductivity penetrates the
ferromagnet along the DW over much larger distances. This happens because the
presence of DW results in a generation of an odd frequency triplet s-wave
component of the condensate. The phenomenon discovered here may help to explain
a recent experiment on high temperature superconductor-ferromagnet bi-lyers.


title:
Spin-squared Hamiltonian of next-to-leading order gravitational
  interaction

abstract:
  The static, i.e., linear momentum independent, part of the next-to-leading
order (NLO) gravitational spin(1)-spin(1) interaction Hamiltonian within the
post-Newtonian (PN) approximation is calculated from a 3-dim. covariant ansatz
for the Hamilton constraint. All coefficients in this ansatz can be uniquely
fixed for black holes. The resulting Hamiltonian fits into the canonical
formalism of Arnowitt, Deser, and Misner (ADM) and is given in their
transverse-traceless (ADMTT) gauge. This completes the recent result for the
momentum dependent part of the NLO spin(1)-spin(1) ADM Hamiltonian for binary
black holes (BBH). Thus, all PN NLO effects up to quadratic order in spin for
BBH are now given in Hamiltonian form in the ADMTT gauge. The equations of
motion resulting from this Hamiltonian are an important step toward more
accurate calculations of templates for gravitational waves.


title:
Effects of non-adiabaticity on the voltage generated by a moving domain
  wall

abstract:
  We determine the voltage generated by a field-driven domain wall, taking into
account non-adiabatic corrections to the motive force induced by the
time-dependent spin Berry phase. Both the diffusive and ballistic transport
regimes are considered. We find that that the non-adiabatic corrections,
together with the contributions due to spin relaxation, determine the voltage
for driving fields smaller than the Walker breakdown limit.


title:
DC and high-frequency conductivity of the organic metals
  beta"-(BEDT-TTF)2SF5RSO3 (R = CH2CF2 and CHF)

abstract:
  The temperature dependences of the electric-transport properties of the
two-dimensional organic conductors beta"-(BEDT-TTF)2SF5CH2CF2SO3,
beta"-(d8-BEDT-TTF)2SF5CH2CF2SO3, and beta"-(BEDT-TTF)2SF5CHFSO3 are measured
by dc methods in and perpendicular to the highly-conducting plane. Microwave
measurements are performed at 24 and 33.5 GHz to probe the high-frequency
behavior from room temperature down to 2 K. Superconductivity is observed in
beta"-(BEDT-TTF)2SF5CH2CF2SO3 and its deuterated analogue. Although all the
compounds remain metallic down to low-temperatures, they are close to a
charge-order transition. This leads to deviations from a simple Drude behavior
of the optical conductivity which become obvious already in the microwave
range. In beta"-(BEDT-TTF)2SF5CH2CF2SO3, for instance, charge fluctuations
cause an increase in microwave resistivity for T < 20 K which is not detected
in dc measurements. beta"-(BEDT-TTF)2SF5CHFSO3 exhibits a simple metallic
behavior at all frequencies. In the dc transport, however, we observe
indications of localization in the perpendicular direction.


title: Variability of B and Be stars in the LMC/SMC: binaries and pulsations

abstract:
  To study the variability of the 523 B and Be stars observed in the Magellanic
clouds with the VLT-FLAMES, we cross-matched the stars of our sample with the
photometric database MACHO, which provides for each star an 8 years lightcurve.
We searched for long, medium, and short-term periodicity and found the
eclipsing binaries in our sample. For these stars, combining, spectroscopy and
photometry, we were able to provide information on several systems of stars
(systemic velocities, ratios of masses, etc). We also present the ratios of
B-binaries to B-non binaries in the LMC/SMC in comparison with the MW. Note
that this ratio is also an important issue to understand the mechanism of
star-formation at low metallicity. We also found the first multiperiodic B and
Be stars in the SMC, in particular the first SMC Beta Cep and SPB, while,
according to the models, pulsations were not foreseen in low metallicity
environments, i.e. typically in the SMC. Our results show that the instability
strips are shifted towards higher temperatures in comparison with the Milky
Way' strips of pulsating B-type stars. By the fact that we found more pulsating
Be stars than pulsating B stars in the SMC, it seems that the fast rotation
favours the presence of pulsations. However, the ratio of pulsating B-type
stars to "non"-pulsating B-type stars at low metallicity is lower than at high
metallicity.


title:
Exclusive SUSY measurements and determination of SUSY parameters from
  LHC data

abstract:
  A selection of exclusive SUSY measurements is presented which can be
performed provided SUSY will be discovered at the LHC. Such measurements allow
to determine the properties of supersymmetry and thus help to pin down the
underlying theoretical model. It is described on an mSUGRA example point how
sparticle masses can be reconstructed from endpoints in mass spectra using
early LHC data. Finally it is shown how well mSUGRA model parameters can be
derived from these measurements.


title:
ZAMS rotational velocities of Be/Oe stars and LGRBs progenitors in the
  Magellanic Clouds

abstract:
  The Large and Small Magellanic Clouds are priviledged environments to perform
tests of theoretical predictions at low metallicity on rotational velocities
and stellar evolution. According to theoretical predictions, the rotational
velocities of B-type stars are expected to be higher in low metallicity
(LMC/SMC) than in high metallicity (MW) environments. To verify the models, we
observed with the VLT-FLAMES 523 B and Be stars, which form, at the moment, the
largest observed sample of these kind of objects in the MCs. We first
determined the stellar fundamental parameters and we found that B and Be stars
rotate faster in the MCs than in the MW. We also determined the first
distribution of the average ZAMS rotational velocities versus the mass of Be
stars. These results indicate that the appearance of Be stars is mass-,
metallicity-, stellar evolution-, and star-formation regions-dependant.
Moreover, the recent models of Long Gamma Ray Bursts progenitors foresee
possible LGRBs progenitors at the SMC's metallicity. We confront these models
with the observed (ZAMS rotational velocities, masses) distributions of the
fastest rotators (Be and Oe stars) in our sample. Furthermore, we compare the
corresponding predicted rates from our study with observed rates of LGRBs.


title:
Complete Positivity of Rieffel's Deformation Quantization by Actions of
  $\mathbb{R}^d$

abstract:
  In this paper we consider C*-algebraic deformations a la Rieffel and show
that every state of the undeformed algebra can be deformed into a state of the
deformed algebra in the sense of a continuous field of states. The construction
is explicit and involves a convolution operator with a particular Gauss
function.


title:
Negative-index bi-anisotropic photonic metamaterial fabricated by direct
  laser writing and silver shadow evaporation

abstract:
  We present the blueprint for a novel negative-index metamaterial. This
structure is fabricated via three-dimensional two-photon direct laser writing
and silver shadow evaporation. The comparison of measured linear optical
spectra with theory shows good agreement and reveals a negative real part of
the refractive index at around 3.85 micrometer wavelength - despite the fact
that the metamaterial structure is bi-anisotropic due to the lack of inversion
symmetry along its surface normal.


title:
Higher-order-in-spin interaction Hamiltonians for binary black holes
  from Poincar\'e invariance

abstract:
  The fulfillment of the space-asymptotic Poincar\'e algebra is used to derive
new higher-order-in-spin interaction Hamiltonians for binary black holes in the
Arnowitt-Deser-Misner canonical formalism almost completing the set of the
formally $1/c^4$ spin-interaction Hamiltonians involving nonlinear spin terms.
To linear order in $G$, the expressions for the $S^3p$- and the
$S^2p^2$-Hamiltonians are completed. It is also shown that there are no quartic
nonlinear $S^4$-Hamiltonians to linear order in $G$.


title: CP-violating Higgs at Tevatron

abstract:
  We analyze the prospect for observing the intermediate neutral Higgs ($h_2$)
boson in its decay to two lighter Higgs bosons ($h_1$) at the Tevatron in the
framework of the CP violating MSSM using the PYTHIA event generator. We
consider the lepton+ 4-jets+ $\met$ channel from $p \bar p \ra W h_2 \ra W h_1
h_1 \ra l \nu_l b \bar b b\bar b$, with two or three tagged $b$ jets. We found
that it is very hard to observe this signature in the LEP-allowed region of
parameter space, due to the small signal efficiency.


title: Recent results from the Pierre Auger Observatory

abstract:
  The main results from the Auger Observatory are described. A steepening of
the spectrum is observed at the highest energies, supporting the expectation
that above $4\times 10^{19}$ eV the cosmic ray energies are significantly
degraded by interactions with the CMB photons (the GZK effect). This is further
supported by the correlations observed above $6\times 10^{19}$ eV with the
distribution of nearby active galaxies, which also show the potential of Auger
to start the era of charged particle astronomy. The lack of observation of
photons or neutrinos strongly disfavors top-down models, and these searches may
approach in the long term the sensitivity required to test the fluxes expected
from the secondaries of the very same GZK process. Bounds on the anisotropies
at EeV energies contradict hints from previous experiments that suggested a
large excess from regions near the Galactic centre or the presence of a dipolar
type modulation of the cosmic ray flux.


title: Wavelet-based integral representation for solutions of the wave equation

abstract:
  An integral representation of solutions of the wave equation as a
superposition of other solutions of this equation is built. The solutions from
a wide class can be used as building blocks for the representation.
Considerations are based on mathematical techniques of continuous wavelet
analysis. The formulas obtained are justified from the point of view of
distribution theory. A comparison of the results with those by G. Kaiser is
carried out. Methods of obtaining physical wavelets are discussed.


title: Substitutional disorder and charge localization in manganites

abstract:
  In the manganites $RE_{1-x}AE_{x}$MnO$_{3}$ ($RE$ and $AE$ being rare-earth
and alkaline-earth elements, respectively) the random distribution of $RE^{3+}$
and $AE^{2+}$ induces random, but correlated, shifts of site energies of charge
carriers in the Mn sites. We consider a realistic model of this diagonal
disorder, in addition to the double-exchange hopping disorder, and investigate
the metal-insulator transition as a function of temperature, across the
paramagnetic-ferromagnetic line, and as a function of doping $x$. Contrary to
previous results, we find that values of parameters, estimated from the
electronic structure of the manganites, are not incompatible with the
possibility of a disorder induced metal to insulator transition accompanying
the ferromagnetic to paramagnetic transition at intermediate doping
($x\sim0.2-0.4$). These findings indicate clearly that substitutional disorder
has to be considered as an important effect when addressing the colossal
magnetoresistance properties of manganites.


title: A Note on trapped Surfaces in the Vaidya Solution

abstract:
  The Vaidya solution describes the gravitational collapse of a finite shell of
incoherent radiation falling into flat spacetime and giving rise to a
Schwarzschild black hole. There has been a question whether closed trapped
surfaces can extend into the flat region (whereas closed outer trapped surfaces
certainly can). For the special case of self-similar collapse we show that the
answer is yes, if and only if the mass function rises fast enough.


title: On (Omega-)Regular Model Checking

abstract:
  Checking infinite-state systems is frequently done by encoding infinite sets
of states as regular languages. Computing such a regular representation of,
say, the set of reachable states of a system requires acceleration techniques
that can finitely compute the effect of an unbounded number of transitions.
Among the acceleration techniques that have been proposed, one finds both
specific and generic techniques. Specific techniques exploit the particular
type of system being analyzed, e.g. a system manipulating queues or integers,
whereas generic techniques only assume that the transition relation is
represented by a finite-state transducer, which has to be iterated. In this
paper, we investigate the possibility of using generic techniques in cases
where only specific techniques have been exploited so far. Finding that
existing generic techniques are often not applicable in cases easily handled by
specific techniques, we have developed a new approach to iterating transducers.
This new approach builds on earlier work, but exploits a number of new
conceptual and algorithmic ideas, often induced with the help of experiments,
that give it a broad scope, as well as good performances.


title:
Cohomological non-rigidity of generalized real Bott manifolds of height
  2

abstract:
  We investigate when two generalized real Bott manifolds of height 2 have
isomorphic cohomology rings with Z/2 coefficients and also when they are
diffeomorphic. It turns out that cohomology rings with Z/2 coefficients do not
distinguish those manifolds up to diffeomorphism in general. This gives a
counterexample to the cohomological rigidity problem for real toric manifolds
posed in \cite{ka-ma08}. We also prove that generalized real Bott manifolds of
height 2 are diffeomorphic if they are homotopy equivalent.


title: Matter-wave dark solitons in a double-well potential

abstract:
  We study stability of the first excited state of quasi-one-dimensional
Bose-Einstein condensates in a double-well potential, which is called
"$\pi$-state". The density notch in the $\pi$-state can be regarded as a
standing dark soliton. From the excitation spectrum, we determine the critical
barrier height, above which the $\pi$-state is dynamically unstable. We find
that the critical barrier height decreases monotonically as the number of
condensate atoms increases. We also simulate the dynamics of the $\pi$-state by
solving the time-dependent Gross-Pitaevskii equation. We show that due to the
dynamical instability the dark soliton starts to move away from the trap center
and exhibits a large-amplitude oscillation.


title: Universality classes for Coulomb frustrated phase separation

abstract:
  We identify two "universality" classes in the Coulomb frustrated phase
separation phenomenon. They correspond to two different kind of electronic
compressibility anomalies often encountered in strongly correlated electronic
systems. We discuss differences and similarities of their corresponding phase
diagrams in two- and three-dimensional systems.


title:
A free action of a finite group on 3-sphere equivalent to a linear
  action

abstract:
  In this paper, by use of techniques associated to Cobordism theory and Morse
theory, we give a proof of Space-Form-Conjecture, i.e. a free action of a
finite group on 3-manifold is equivalent to a linear action.


title: Phase transition in conservative diffusive contact processes

abstract:
  We determine the phase diagrams of conservative diffusive contact processes
by means of numerical simulations. These models are versions of the ordinary
diffusive single-creation, pair-creation and triplet-creation contact processes
in which the particle number is conserved. The transition between the frozen
and active states was determined by studying the system in the subcritical
regime and the nature of the transition, whether continuous or first order, was
determined by looking at the fractal dimension of the critical cluster. For the
single-creation model the transition remains continuous for any diffusion rate.
For pair- and triplet-creation models, however, the transition becomes first
order for high enough diffusion rate. Our results indicate that in the limit of
infinite diffusion rate the jump in density equals 2/3 for the pair-creation
model and 5/6 for the triplet-creation model.


title: State Space Reconstruction for Multivariate Time Series Prediction

abstract:
  In the nonlinear prediction of scalar time series, the common practice is to
reconstruct the state space using time-delay embedding and apply a local model
on neighborhoods of the reconstructed space. The method of false nearest
neighbors is often used to estimate the embedding dimension. For prediction
purposes, the optimal embedding dimension can also be estimated by some
prediction error minimization criterion. We investigate the proper state space
reconstruction for multivariate time series and modify the two abovementioned
criteria to search for optimal embedding in the set of the variables and their
delays. We pinpoint the problems that can arise in each case and compare the
state space reconstructions (suggested by each of the two methods) on the
predictive ability of the local model that uses each of them. Results obtained
from Monte Carlo simulations on known chaotic maps revealed the non-uniqueness
of optimum reconstruction in the multivariate case and showed that prediction
criteria perform better when the task is prediction.


title:
Contact process with long-range interactions: a study in the ensemble of
  constant particle number

abstract:
  We analyze the properties of the contact process with long-range interactions
by the use of a kinetic ensemble in which the total number of particles is
strictly conserved. In this ensemble, both annihilation and creation processes
are replaced by an unique process in which a particle of the system chosen at
random leaves its place and jumps to an active site. The present approach is
particularly useful for determining the transition point and the nature of the
transition, whether continuous or discontinuous, by evaluating the fractal
dimension of the cluster at the emergence of the phase transition. We also
present another criterion appropriate to identify the phase transition that
consists of studying the system in the supercritical regime, where the presence
of a "loop" characterizes the first-order transition. All results obtained by
the present approach are in full agreement with those obtained by using the
constant rate ensemble, supporting that, in the thermodynamic limit the results
from distinct ensembles are equivalent.


title: Coherent Diffraction Imaging of Single 95nm Nanowires

abstract:
  Photonic or electronic confinement effects in nanostructures become
significant when one of their dimension is in the 5-300 nm range. Improving
their development requires the ability to study their structure - shape, strain
field, interdiffusion maps - using novel techniques. We have used coherent
diffraction imaging to record the 3-dimensionnal scattered intensity of single
silicon nanowires with a lateral size smaller than 100 nm. We show that this
intensity can be used to recover the hexagonal shape of the nanowire with a
28nm resolution. The article also discusses limits of the method in terms of
radiation damage.


title: Dimensional Reduction and Hadronic Processes

abstract:
  We consider the application of regularization by dimensional reduction to NLO
corrections of hadronic processes. The general collinear singularity structure
is discussed, the origin of the regularization-scheme dependence is identified
and transition rules to other regularization schemes are derived.


title:
Quasimonoenergetic electron beams produced by colliding cross-polarized
  laser pulses in underdense plasmas

abstract:
  The interaction of two laser pulses in an underdense plasma has proven to be
able to inject electrons in plasma waves, thus providing a stable and tunable
source of electrons. Whereas previous works focused on the "beatwave" injection
scheme in which two lasers with the same polarization collide in a plasma, this
present letter studies the effect of polarization and more specifically the
interaction of two colliding cross-polarized laser pulses. It is shown both
theoretically and experimentally that electrons can also be pre-accelerated and
injected by the stochastic heating occurring at the collision of two
cross-polarized lasers and thus, a new regime of optical injection is
demonstrated. It is found that injection with cross-polarized lasers occurs at
higher laser intensities.


title:
Geometric dephasing-limited Hanle effect in long-distance lateral
  silicon spin transport devices

abstract:
  Evidence of spin precession and dephasing ("Hanle effect") induced by an
external magnetic field is the only unequivocal proof of spin-polarized
conduction electron transport in semiconductor devices. However, when spin
dephasing is very strong, Hanle effect in a uniaxial magnetic field can be
impossible to measure. Using a Silicon device with lateral injector-detector
separation over 2 millimeters, and geometrically-induced dephasing making spin
transport completely incoherent, we show experimentally and theoretically that
Hanle effect can still be measured using a two-axis magnetic field.


title: Relay vs. User Cooperation in Time-Duplexed Multiaccess Networks

abstract:
  The performance of user-cooperation in a multi-access network is compared to
that of using a wireless relay. Using the total transmit and processing power
consumed at all nodes as a cost metric, the outage probabilities achieved by
dynamic decode-and-forward (DDF) and amplify-and-forward (AF) are compared for
the two networks. A geometry-inclusive high signal-to-noise ratio (SNR) outage
analysis in conjunction with area-averaged numerical simulations shows that
user and relay cooperation achieve a maximum diversity of K and 2 respectively
for a K-user multiaccess network under both DDF and AF. However, when
accounting for energy costs of processing and communication, relay cooperation
can be more energy efficient than user cooperation, i.e., relay cooperation
achieves coding (SNR) gains, particularly in the low SNR regime, that override
the diversity advantage of user cooperation.


title:
Testing the inverse-Compton catastrophe scenario in the intra-day
  variable blazar S5 0716+71, III. Rapid and correlated flux density
  variability from radio to sub-mm bands

abstract:
  The BL Lac object S5 0716+71 was observed in a global multi-frequency
campaign to search for rapid and correlated flux density variability and
signatures of an inverse-Compton (IC) catastrophe during the states of extreme
apparent brightness temperatures. The observing campaign involved simultaneous
monitoring at radio to IR/optical wavelengths centered around a 500-ks INTEGRAL
pointing (November 10-17, 2003). We present the combined analysis and results
of the cm- to sub-mm observations including a detailed study of the inter- to
intra-day variability and spectral characteristics of 0716+714. We further
constrain the variability brightness temperatures (T_B) and Doppler factors
(delta) comparing the radio-bands with the hard X-ray emission (3-200 keV).
0716+714 was in an exceptionally high state (outburst) and different (slower)
phase of short-term variability. The flux density variability in the cm- to
mm-bands is dominated by a correlated, ~4 day time scale amplitude increase of
up to ~35% systematically more pronounced towards shorter wavelengths. This
contradicts expectations from standard interstellar scintillation (ISS) and
suggests a source-intrinsic origin of the variability. The derived lower limits
to T_B exceed the 10^12 K IC-limit by up to 3-4 orders of magnitude. Assuming
relativistic boosting, we obtain robust and self-consistent lower limits of
delta >= 5-33, in good agreement with delta_VLBI obtained from VLBI studies and
the IC-Doppler factors delta_IC > 14-16 obtained from the INTEGRAL data. Since
a strong contribution from ISS can be excluded and a simultaneous IC
catastrophe was not observed, we conclude that relativistic Doppler boosting
naturally explains the apparent violation of the theoretical limits within
standard synchrotron-self-Compton (SSC) jet models of AGN.


title:
Non-equilibrium self-assembly of a filament coupled to ATP/GTP
  hydrolysis

abstract:
  We study the stochastic dynamics of growth and shrinkage of single actin
filaments or microtubules taking into account insertion, removal, and ATP/GTP
hydrolysis of subunits. The resulting phase diagram contains three different
phases: a rapidly growing phase, an intermediate phase and a bound phase. We
analyze all these phases, with an emphasis on the bound phase. We also discuss
how hydrolysis affects force-velocity curves. The bound phase shows features of
dynamic instability, which we characterize in terms of the time needed for the
ATP/GTP cap to disappear as well as the time needed for the filament to reach a
length of zero, i.e., (to collapse) for the first time. We obtain exact
expressions for all these quantities, which we test using Monte Carlo
simulations.


title:
Turning Point Prediction of Oscillating Time Series using Local Dynamic
  Regression Models

abstract:
  In the prediction of oscillating time series, the interest is in the turning
points of successive oscillations rather than the samples themselves. For this
purpose a scheme has been proposed; the state space reconstruction is limited
to the turning points and the local (nearest neighbor) model is modified in
order to predict the turning point magnitudes and times. This approach is
extended here using a local dynamic regression model on both turning point
magnitudes and times. Simulations on oscillating nonlinear systems show that
the proposed approach gives better predictions of turning points than the
standard local model applied to all the samples of the oscillating time series.


title: Continuous LERW Started from Interior Points

abstract:
  We use the whole-plane Loewner equation to define a family of continuous LERW
in finitely connected domains that are started from interior points. These
continuous LERW satisfy conformal invariance, preserve some continuous local
martingales, and are the scaling limits of the corresponding discrete LERW on
the discrete approximation of the domains.


title: Circular hydraulic jump in generalized-Newtonian fluids

abstract:
  We carry out an analytical study of laminar circular hydraulic jumps, in
generalized-Newtonian fluids obeying the two-parametric power-law model of
Ostwald-de Waele. Under the boundary-layer approximation we obtained exact
expressions determining the flow, an implicit relation for the jump radius is
derived. Corresponding results for Newtonian fluids can be retrieved as a
limiting case for the flow behavior index n=1, predictions are made for fluids
deviating from Newtonian behavior.


title: A hybrid approach to Fermi operator expansion

abstract:
  In a recent paper we have suggested that the finite temperature density
matrix can be computed efficiently by a combination of polynomial expansion and
iterative inversion techniques. We present here significant improvements over
this scheme. The original complex-valued formalism is turned into a purely real
one. In addition, we use Chebyshev polynomials expansion and fast summation
techniques. This drastically reduces the scaling of the algorithm with the
width of the Hamiltonian spectrum, which is now of the order of the cubic root
of such parameter. This makes our method very competitive for applications to
ab-initio simulations, when high energy resolution is required.


title:
The \rho\rho interaction in the hidden gauge formalism and the f_0(1370)
  and f_2(1270) resonances

abstract:
  We have studied the interaction of vectors mesons within the hidden gauge
formalism and applied it to the particular case of the $\rho \rho$ interaction.
We find a strong attraction in the isospin, spin channels I,S=0,0 and 0,2,
which is enough to bind the $\rho \rho$ system. We also find that the
attraction in the I,S=0,2 channel is much stronger than in the 0,0 case. The
states develop a width when the $\rho$ mass distribution is considered, and
particularly when the $\pi \pi$ decay channel is turned on. Using a
regularization scheme with cut offs of natural size, we obtain results in fair
agreement with the mass and the width of the $f_0(1370)$ and $f_2(1270)$ meson
states, providing a natural explanation of why the tensor state is more bound
than the scalar and offering a new picture for these states, which would be
dynamically generated from the $\rho \rho$ interaction or, in simpler words,
$\rho \rho$ molecular states.


title: Kinetic Theory for Electron Dynamics Near a Positive Ion

abstract:
  A theoretical description of time correlation functions for electron
properties in the presence of a positive ion of charge number Z is given. The
simplest case of an electron gas distorted by a single ion is considered. A
semi-classical representation with a regularized electron - ion potential is
used to obtain a linear kinetic theory that is asymptotically exact at short
times. This Markovian approximation includes all initial (equilibrium) electron
- electron and electron - ion correlations through renormalized pair
potentials. The kinetic theory is solved in terms of single particle
trajectories of the electron - ion potential and a dielectric function for the
inhomogeneous electron gas. The results are illustrated by a calculation of the
autocorrelation function for the electron field at the ion. The dependence on
charge number Z is shown to be dominated by the bound states of the effective
electron - ion potential. On this basis, a very simple practical representation
of the trajectories is proposed and shown to be accurate over a wide range
including strong electron - ion coupling. This simple representation is then
used for a brief analysis of the dielectric function for the inhomogeneous
electron gas.


title: Modelling Electron Spin Accumulation in a Metallic Nanoparticle

abstract:
  A model describing spin-polarized current via discrete energy levels of a
metallic nanoparticle, which has strongly asymmetric tunnel contacts to two
ferromagnetic leads, is presented.
  In absence of spin-relaxation, the model leads to a spin-accumulation in the
nanoparticle, a difference ($\Delta\mu$) between the chemical potentials of
spin-up and spin-down electrons, proportional to the current and the Julliere's
tunnel magnetoresistance. Taking into account an energy dependent
spin-relaxation rate $\Omega (\omega)$, $\Delta\mu$ as a function of bias
voltage ($V$) exhibits a crossover from linear to a much weaker dependence,
when $|e|\Omega (\Delta\mu)$ equals the spin-polarized current through the
nanoparticle. Assuming that the spin-relaxation takes place via electron-phonon
emission and Elliot-Yafet mechanism, the model leads to a crossover from linear
to $V^{1/5}$ dependence. The crossover explains recent measurements of the
saturation of the spin-polarized current with $V$ in Aluminum nanoparticles,
and leads to the spin-relaxation rate of $\approx 1.6 MHz$ in an Aluminum
nanoparticle of diameter $6nm$, for a transition with an energy difference of
one level spacing.


title: The Complexity of the Evolution of Graph Labelings

abstract:
  We study the {\sc Graph Relabeling Problem}--given an undirected, connected,
simple graph $G = (V,E)$, two labelings $L$ and $L'$ of $G$, and label {\em
flip} or {\em mutation} functions determine the complexity of transforming or
evolving the labeling $L$ into $L'$\@. The transformation of $L$ into $L'$ can
be viewed as an evolutionary process governed by the types of flips or
mutations allowed. The number of applications of the function is the duration
of the evolutionary period. The labels may reside on the vertices or the edges.
We prove that vertex and edge relabelings have closely related computational
complexities. Upper and lower bounds on the number of mutations required to
evolve one labeling into another in a general graph are given. Exact bounds for
the number of mutations required to evolve paths and stars are given. This
corresponds to computing the exact distance between two vertices in the
corresponding {\em Cayley graph}. We finally explore both vertex and edge
relabeling with {\em privileged labels}, and resolve some open problems by
providing precise characterizations of when these problems are solvable. Many
of our results include algorithms for solving the problems, and in all cases
the algorithms are polynomial-time. The problems studied have applications in
areas such as bioinformatics, networks, and VLSI.


title:
Evidence for Fermi surface reconstruction in the static stripe phase of
  La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_{4}$, $x=1/8$

abstract:
  We present a photoemission study of La$_{0.8-x}$Eu$_{0.2}$Sr$_x$CuO$_{4}$
with doping level $x$=1/8, where the charge carriers are expected to order
forming static stripes. Though the local probes in direct space seem to be
consistent with this idea, there has been little evidence found for such
ordering in quasiparticle dispersions. We show that the Fermi surface topology
of the 1/8 compound develops notable deviations from that observed for La$_{2-
x}$Sr$_x$CuO$_{4}$ in a way consistent with the FS reconstruction expected for
the scattering on the antiphase stripe order.


title: Symmetric Points in the Landscape as Cosmological Attractors

abstract:
  In the landscape, if there is to be any prospect of scientific prediction, it
is crucial that there be states which are distinguished in some way. The
obvious candidates are states which exhibit symmetries. Here we focus on states
which exhibit discrete symmetries. Such states are rare, but one can speculate
that they are cosmological attractors. We investigate the problem in model
landscapes and cosmologies which capture some of the features of candidate flux
landscapes. In non-supersymmetric theories we find no evidence that such states
might be cosmologically favored. In supersymmetric theories, simple arguments
suggest that states which exhibit $R$ symmetries might be. Our considerations
lead us to raise questions about some popular models of eternal inflation.


title: Tunable Spin Filtering through an Aluminum Nanoparticle

abstract:
  Spin-polarized current through an Al nanoparticle in tunnel contact with two
ferromagnets is measured as a function of the direction of the applied magnetic
field. The nanoparticle filters the spin of injected electrons along a
direction specified by the magnetic field. The characteristic field scale for
the filtering corresponds to a lower limit of $8ns$ for the spin-dephasing
time. Spin polarized current versus applied voltage increases stepwise,
confirming that the spin relaxation time is long only in the ground state and
the low-lying excited states of the nanoparticle.


title: Small groups of finite Morley rank with involutions

abstract:
  We consider groups of finite Morley rank with solvable local subgroups of
even and mixed types. We also consider miscellaneous aspects of small groups of
finite Morley rank of odd type.


title: Chern-Weil homomorphism in twisted equivariant cohomology

abstract:
  We describe the Cartan and Weil models of twisted equivariant cohomology
together with the Cartan homomorphism among the two, and we extend the
Chern-Weil homomorphism to the twisted equivariant cohomology. We clarify that
in order to have a cohomology theory, the coefficients of the twisted
equivariant cohomology must be taken in the completed polynomial algebra over
the dual Lie algebra of $G$. We recall the relation between the equivariant
cohomology of exact Courant algebroids and the twisted equivariant cohomology,
and we show how to endow with a generalized complex structure the finite
dimensional approximations of the Borel construction $M\times_G EG_k$, whenever
the generalized complex manifold $M$ possesses a Hamiltonian $G$ action.


title: Non-Gaussianity from Baryon Asymmetry

abstract:
  We study a scenario that large non-Gaussianity arises from the baryon
asymmetry of the Universe. There are baryogenesis scenarios containing a light
scalar field, which may result in baryonic isocurvature perturbations with some
amount of non-Gaussianity. As an explicit example we consider the Affleck-Dine
mechanism and show that a flat direction of the supersymmeteric standard model
can generate large non-Gaussianity in the curvature perturbations, satisfying
the observational constraints on the baryonic isocurvature perturbations. The
sign of a non-linearity parameter, f_{NL}, is negative, if the Affleck-Dine
mechanism accounts for the observed baryon asymmetry; otherwise it can be
either positive or negative.


title:
A de Finetti representation theorem for infinite dimensional quantum
  systems and applications to quantum cryptography

abstract:
  According to the quantum de Finetti theorem, if the state of an N-partite
system is invariant under permutations of the subsystems then it can be
approximated by a state where almost all subsystems are identical copies of
each other, provided N is sufficiently large compared to the dimension of the
subsystems. The de Finetti theorem has various applications in physics and
information theory, where it is for instance used to prove the security of
quantum cryptographic schemes. Here, we extend de Finetti's theorem, showing
that the approximation also holds for infinite dimensional systems, as long as
the state satisfies certain experimentally verifiable conditions. This is
relevant for applications such as quantum key distribution (QKD), where it is
often hard - or even impossible - to bound the dimension of the information
carriers (which may be corrupted by an adversary). In particular, our result
can be applied to prove the security of QKD based on weak coherent states or
Gaussian states against general attacks.


title: Gaugino condensation in an improved heterotic M-theory

abstract:
  Gaugino condensation is discussed in the context of a consistent new version
of low energy heterotic M-theory. The four dimensional reduction of the theory
is described, based on simple boson and fermion backgrounds. This is
generalised to include gaugino condenstates and various background fluxes, some
with non-trivial topology. It is found that condensate and quantised flux
contributions to the four-dimensional superpotential contain no corrections due
to the warping of the higher dimensional metric.


title: Wolfgang Kummer and the Vienna School of Dilaton (Super-)Gravity

abstract:
  Wolfgang Kummer was well known for his passion for axial gauges and for the
formulation of gravity in terms of Cartan variables. The combination of the two
applied to two dimensional dilaton gravity is the basis of the "Vienna School",
which provided numerous significant results over the last seventeen years. In
this review we trace the history of this success with particular emphasis on
dilaton supergravity. We also present some previously unpublished results on
the structure of non-local vertices in quantum dilaton supergravity with
non-minimally coupled matter.


title:
Evolution of proto-galaxy-clusters to their present form: theory and
  observations

abstract:
  From hydro-gravitational-dynamics theory HGD, gravitational structure
formation begins 30,000 years after the turbulent big bang by fragmentation
into super-cluster-voids and super-clusters. Proto-galaxies in linear and
spiral clusters are the smallest fragments to emerge from the plasma epoch at
decoupling at 10^13 s with a turbulent morphology determined by the plasma
turbulence and the Nomura scale 10^20 m, which is determined by gravity, the
fossilized density and rate-of-strain of the 10^12 s time of first structure
and the large photon viscosity of the plasma. After decoupling, the gas
proto-galaxies fragment into 10^36 kg proto-globular-star-cluster PGC clumps of
earth-mass 10^25 kg hot gas clouds that eventually freeze to form
primordial-fog-particle PFP dark matter planets. The rotation of galaxies
reflects density gradients of big bang turbulent mixing and the sonic expansion
of proto-super-cluster-voids. The spin axis appears for low wavenumber
spherical harmonic components of CMB temperature anomalies, the Milky Way and
galaxies of the local group, and extends to 4.5x10^25 m (1.5 Gpc) in quasar
polarization vectors, supporting a big bang turbulence origin. Gas
proto-galaxies stick together by frictional processes of the frozen gas
planets, just as PGCs have been meta-stable for the 13.7 Gyr age of the
universe. Evidence of PGC-friction is inferred from the local group Hubble
diagram and from redshift anomalies of Hickson compact galaxy groups such as
the Stephan Quintet compared to Sloan Digital Sky Survey SDSS galaxy
observations.


title:
Control of entanglement and two-qubit quantum gates with atoms crossing
  a detuned optical cavity

abstract:
  A scheme is proposed to generate an entangled state between two (Lambda-type)
four-level atoms that interact effectively by means of a detuned optical cavity
and a laser beam that acts perpendicularly to the cavity axis. It is shown how
the degree of entanglement for two atoms passing through the cavity can be
controlled by manipulating their velocity and the (initial) distance between
the atoms. In addition, three realistic schemes are suggested to implement the
two-qubit gates within the framework of the suggested atom-cavity-laser setup,
namely, the i-swap gate, controlled-Z gate and the controlled-NOT gate. For all
these schemes, we analyze and discuss the atomic velocities and inter-atomic
distances for which these gates are realized most reliably.


title:
Precision Measurement of the n-3He Incoherent Scattering Length Using
  Neutron Interferometry

abstract:
  We report the first measurement of the low-energy neutron-$^3$He incoherent
scattering length using neutron interferometry: $b_i' = (-2.512\pm
0.012{statistical}\pm0.014{systematic})$ fm. This is in good agreement with a
recent calculation using the AV18+3N potential. The neutron-$^3$He scattering
lengths are important for testing and developing nuclear potential models that
include three nucleon forces, effective field theories for few-body nuclear
systems, and neutron scattering measurements of quantum excitations in liquid
helium. This work demonstrates the first use of a polarized nuclear target in a
neutron interferometer.


title:
Some remarks on a result of Jensen and tilting modules for $\SL_3(k)$
  and $q$-$\GL_3(k)$

abstract:
  This paper reviews a result of Jensen on characters of some tilting modules
for $\SL_3(k)$, where $k$ has characteristic at least five and fills in some
gaps in the proof of this result. We then apply the result to finding some
decomposition numbers for three part partitions for the symmetric group and the
Hecke algebra. We review what is known for characteristic two and three. The
quantum case is also considered: analogous results hold for the mixed quantum
group where $q$ is an $l$th root of unity with $l$ at least three and thus also
hold for the associated Hecke algebra.


title: Spin-Diffusion Lengths in Dilute Cu(Ge) and Ag(Sn) Alloys

abstract:
  We use current-perpendicular-to-plane (CPP) exchange-biased spin-valves to
directly measure spin diffusion lengths lsf for N = Cu(2.1 at.%Ge) and Ag(3.6
at.%Sn) alloys. We find lsf(Cu2%Ge)) = 117+10-6 nm and lsf(Ag4%Sn)= 39 +/- 3
nm. The good agreement of this lsf(Cu2%Ge) with the value lsf(Cu2%Ge) = 121 +/-
10 nm derived from an independent spin-orbit cross-section measurement for Ge
in Cu, quantitatively validates the use of Valet-Fert theory for CPP-MR data
analysis to layer thicknesses several times larger than had been done before.
  From the value of lsf(Ag4%Sn), we predict the ESR spin-orbit cross-section
for Sn impurities in Ag.


title:
Reciprocity and rationality for the greedy normal form of a Coxeter
  group

abstract:
  We show that the characteristic series for the greedy normal form of a
Coxeter group is always a rational series, and prove a reciprocity formula for
this series when the group is right-angled and the nerve is Eulerian. As
corollaries we obtain many of the known rationality and reciprocity results for
the growth series of Coxeter groups as well as some new ones.