title:
Structural phases of strained LaAlO3 driven by octahedral tilt
  instabilities

abstract:
  We investigate the effect of epitaxial strain on [001]-oriented LaAlO3 using
first-principles density functional calculations. We find a series of
structural phase transitions between states characterized by distinct patterns
of tilting of the AlO6 octahedra. By tuning the biaxial strain from compressive
to tensile, we induce an evolution in the crystal structure in which the tilt
axis changes from out-of-plane to in-plane, corresponding to space groups
I4/mcm and Imma. We also study the effect of uniaxial relaxation of the usual
biaxial epitaxial constraint and explore this as a mechanism for selectively
stabilizing different patterns of octahedral tilts.


title:
Curvature Effect of a Non-Power-Law Spectrum and Spectral Evolution of
  GRB X-Ray Tails

abstract:
  The apparent spectral evolution observed in the steep decay phase of many GRB
early afterglows raises a great concern of the high-latitude "curvature effect"
interpretation of this phase. However, previous curvature effect models only
invoked a simple power law spectrum upon the cessation of the prompt internal
emission. We investigate a model that invokes the "curvature effect" of a more
general non-power-law spectrum and test this model with the Swift/XRT data of
some GRBs. We show that one can reproduce both the observed lightcurve and the
apparent spectral evolution of several GRBs using a model invoking a power-law
spectrum with an exponential cut off. GRB 050814 is presented as an example.


title: Symplectic fillings of links of quotient surface singularities

abstract:
  We study symplectic deformation types of minimal symplectic fillings of links
of quotient surface singularities. In particular, there are only finitely many
symplectic deformation types for each quotient surface singularity.


title:
Early Standard Model Measurement and Determination of Standard Model
  Background for Searches

abstract:
  The Large Hadron Collider (LHC) at CERN in Geneva (Switzerland) will go in
operation in the coming months and will soon enable us to analyze the highest
energy collisions ever produced at an accelerator. Beyond Standard Model
searches at LHC require a detailed understanding of the detector performance,
reconstruction algorithms and triggering. Precision measurements of Standard
Model processes are also mandatory to acquire the necessary knowledge of
Standard Model background. Both ATLAS and CMS efforts are hence addressed to
determine the best calibration candles and to design a realistic plan for the
initial period of data taking.


title: A New Hypoelliptic Operator on Almost CR Manifolds

abstract:
  The aim of this paper is to present the construction, out of the Kohn-Rossi
complex, of a new hypoelliptic operator $Q_{L}$ on almost CR manifolds equipped
with a real structure. The operator acts on all (p,q)-forms, but when
restricted to (p,0)-forms and (p,n)-forms it is a sum of squares up to sign
factor and lower order terms. Therefore, only a finite type condition condition
is needed to have hypoellipticity on those forms. However, outside these forms
$Q_{L}$ may fail to be hypoelliptic, as it is shown in the example of the
Heisenberg group. We also look at the Fredholm properties of $Q_{L}$ and show
that the corresponding Fredholm index is zero.


title: Parton Distribution Functions: Impact of HERA

abstract:
  Recent progresses of the proton structure measurements and determination of
parton distribution functions by $ep$ collisions at HERA are introduced.


title: Relative-Velocity-Dependent Weber-type Models in Electromagnetism

abstract:
  This article reconsiders the relative-velocity-dependent approach to modeling
electromagnetism that was proposed initially by Weber before data from
cathode-ray-tube (CRT) experiments was available. It is shown that identifying
the nonlinear, relative-velocity terms using CRT data results in a model, which
not only captures standard relativistic effects in optics, high-energy
particles, and gravitation, but also explains apparent discrepancies between
predicted and measured energy (i) in high-energy-particle absorption
experiments and (ii) in the classical beta-ray spectrum of radium-E.


title: Homotopy types of topological stacks

abstract:
  We define the notion of {\em classifying space} of a topological stack and
show that every topological stack \X has a classifying space X which is a
topological space well-defined up to weak homotopy equivalence. Under a certain
paracompactness condition on \X, we show that X is actually well-defined up to
homotopy equivalence. These results are formulated in terms of functors from
the category of topological stacks to the (weak) homotopy category of
topological spaces. We prove similar results for (small) diagrams of
topological stacks.


title:
Meromorphic functions with linearly distributed values and Julia sets of
  rational functions

abstract:
  If the preimage of a four-point set under a meromorphic function belongs to
the real line, then the image of the real line is contained in a circle in the
Riemann sphere. We include an application of this result to holomorphic
dynamics: if the Julia set of a rational function is contained in a smooth
curve then it is contained in a circle.


title:
Numerical diagonalization analysis of the criticality of the
  (2+1)-dimensional XY model: Off-diagonal Novotny's method

abstract:
  The criticality of the (2+1)-dimensional XY model is investigated with the
numerical diagonalization method. So far, it has been considered that the
diagonalization method would not be very suitable for analyzing the criticality
in large dimensions (d \ge 3); in fact, the tractable system size with the
diagonalization method is severely restricted. In this paper, we employ
Novotny's method, which enables us to treat a variety of system sizes
N=6,8,...,20 (N: the number of spins constituting a cluster). For that purpose,
we develop an off-diagonal version of Novotny's method to adopt the
off-diagonal (quantum-mechanical XY) interaction. Moreover, in order to improve
the finite-size-scaling behavior, we tune the coupling-constant parameters to a
scale-invariant point. As a result, we estimate the critical indices as
\nu=0.675(20) and \gamma/\nu=1.97(10).


title:
Riesz $s$-equilibrium measures on $d$-rectifiable sets as $s$ approaches
  $d$

abstract:
  Let $A$ be a compact set in ${\mathbb R}^p$ of Hausdorff dimension $d$. For
$s\in(0,d)$, the Riesz $s$-equilibrium measure $\mu^s$ is the unique Borel
probability measure with support in $A$ that minimizes $$
I_s(\mu):=\iint\frac{1}{|x-y|^s}d\mu(y)d\mu(x)$$ over all such probability
measures. If $A$ is strongly $({\mathcal H}^d, d)$-rectifiable, then $\mu^s$
converges in the weak-star topology to normalized $d$-dimensional Hausdorff
measure restricted to $A$ as $s$ approaches $d$ from below.


title: Casimir effect in toroidally compactified de Sitter spacetime

abstract:
  Vacuum energy density and stresses are investigated for a scalar field with
general curvature coupling parameter in (D+1)-dimensional de Sitter spacetime
with an arbitrary number of toroidally compactified spatial dimensions. The
corresponding expectation values are presented in the form of the sum of the
vacuum expectation values in uncompactified dS spacetime and the part induced
by the non-trivial topology. In the early stages of the cosmological evolution
the topological parts dominate. In this limit the behavior of the Casimir
densities does not depend on the curvature coupling parameter and coincides
with that for a conformally coupled massless field. At late stages of the
cosmological expansion the expectation values are dominated by the part
corresponding to uncompactified dS spacetime. The vanishing of the topological
parts is monotonic or oscillatory in dependence of the mass and the curvature
coupling parameter of the field.


title: Pixel Hit Reconstruction with the CMS Detector

abstract:
  We present a new technique for pixel hit reconstruction with the CMS pixel
detector. The technique is based on fitting the pixel cluster projections to
templates obtained using a detailed simulation called Pixelav. Pixelav
successfully describes the profiles of clusters measured in beam tests of
radiation-damaged sensors. Originally developed to optimally estimate the
coordinates of hits after the radiation damage, the technique has superior
performance before irradiation as well, reducing the resolution tails of
reconstructed track parameters and significantly reducing the light quark
background of tagged b-quarks. It is the only technique currently available to
simulate hits from a radiation-damaged detector.


title:
High-frequency corrections to the detector response and their effect on
  searches for gravitational waves

abstract:
  Searches for gravitational waves with km-scale laser interferometers often
involve the long-wavelength approximation to describe the detector response.
The prevailing assumption is that the corrections to the detector response due
to its finite size are small and the errors due to the long-wavelength
approximation are negligible. Recently, however, Baskaran and Grishchuk (2004
Class. Quantum Grav. 21 4041) found that in a simple Michelson interferometer
such errors can be as large as 10 percent. For more accurate analysis, these
authors proposed to use a linear-frequency correction to the long wavelength
approximation. In this paper we revisit these calculations. We show that the
linear-frequency correction is inadequate for certain locations in the sky and
therefore accurate analysis requires taking into account the exact formula,
commonly derived from the photon round-trip propagation time. Also, we extend
the calculations to include the effect of Fabry-Perot resonators in the
interferometer arms. Here we show that a simple approximation which combines
the long-wavelength Michelson response with the single-pole approximation to
the Fabry-Perot transfer function produces rather accurate results. In
particular, the difference between the exact and the approximate formulae is at
most 2-3 percent for those locations in the sky where the detector response is
greater than half of its maximum value. We analyse the impact of such errors on
detection sensitivity and parameter estimation in searches for periodic
gravitational waves emitted by a known pulsar, and in searches for an isotropic
stochastic gravitational-wave background. At frequencies up to 1 kHz, the
effect of such errors is at most 1-2 percent. For higher frequencies, or if
more accuracy is required, one should use the exact formula for the response.


title: Rotation and surface abundance peculiarities in A-type stars

abstract:
  In an attempt of clarifying the connection between the photospheric abundance
anomalies and the stellar rotation as well as of exploring the nature of
"normal A" stars, the abundances of seven elements (C, O, Si, Ca, Ti, Fe, and
Ba) and the projected rotational velocity for 46 A-type field stars were
determined by applying the spectrum-fitting method to the high-dispersion
spectral data obtained with BOES at BOAO. We found that the peculiarities
(underabundances of C, O, and Ca; an overabundance of Ba) seen in slow rotators
efficiently decrease with an increase of rotation, which almost disappear at
v_e sin i > 100 km s^-1. This further suggests that stars with sufficiently
large rotational velocity may retain the original composition at the surface
without being altered. Considering the subsolar tendency (by several tenths dex
below) exhibited by the elemental abundances of such rapidly-rotating
(supposedly normal) A stars, we suspect that the gas metallicity may have
decreased since our Sun was born, contrary to the common picture of galactic
chemical evolution.


title:
Giant frictional drag in strongly interacting bilayers near filling
  factor one

abstract:
  We study the frictional drag in high mobility, strongly interacting GaAs
bilayer hole systems in the vicinity of the filling factor $\nu=1$ quantum Hall
state (QHS), at the same fillings where the bilayer resistivity displays a
reentrant insulating phase. Our measurements reveal a very large longitudinal
drag resistivity ($\rho^{D}_{xx}$) in this regime, exceeding 15 k$\Omega/\Box$
at filling factor $\nu=1.15$. $\rho^{D}_{xx}$ shows a weak temperature
dependence and appears to saturate at a finite, large value at the lowest
temperatures. Our observations are consistent with theoretical models positing
a phase separation, e.g. puddles of $\nu=1$ QHS embedded in a different state,
when the system makes a transition from the coherent $\nu=1$ QHS to the weakly
coupled $\nu=2$ QHS.


title:
Differential equation for local magnetization in the boundary Ising
  model

abstract:
  We show that the local magnetization in the massive boundary Ising model on
the half-plane with boundary magnetic field satisfies second order linear
differential equation whose coefficients are expressed through Painleve
function of the III kind.

categories: math-ph cond-mat.stat-mech hep-th math.MP nlin.SI


title: Orbital Selective Superconductivity in Two-Orbital Asymmetric t-J Models

abstract:
  We present the zero-temperature superconducting (SC) ground states of the
two-orbital asymmetric $t-J$ model on a square lattice by means of the
auxiliary-boson approach. Besides the two-gap SC phase, we find an orbital
selective SC (OSSC) phase, which is simultaneously SC in one orbit and normal
in another orbit. The novel OSSC phase is stable only for sufficient asymmetric
degree in orbital space and doping concentration. The pairing symmetry of the
SC phase is s-wave-like in most doping regime, against the d-wave symmetry of
the single-orbital $t-J$ model in a square lattice. The implication of the
present scenario on multi-orbital heavy fermion and iron-based superconductors
is also discussed.


title:
Bias and angular dependence of spin-transfer torque in magnetic tunnel
  junctions

abstract:
  We use spin-transfer-driven ferromagnetic resonance (ST-FMR) to measure the
spin-transfer torque vector T in MgO-based magnetic tunnel junctions as a
function of the offset angle between the magnetic moments of the electrodes and
as a function of bias, V. We explain the conflicting conclusions of two
previous experiments by accounting for additional terms that contribute to the
ST-FMR signal at large |V|. Including the additional terms gives us improved
precision in the determination of T(V), allowing us to distinguish among
competing predictions. We determine that the in-plane component of has a weak
but non-zero dependence on bias, varying by 30-35% over the bias range where
the measurements are accurate, and that the perpendicular component can be
large enough to be technologically significant. We also make comparisons to
other experimental techniques that have been used to try to measure T(V).


title: Some Characterizations of Domination

abstract:
  We show that a cocycle has a dominated splitting if and only if there is a
uniform exponential gap between singular values of its iterates. Then we
consider sets $\Sigma$ in $GL(d,\mathbb{R})$ with the property that any cocycle
with values in $\Sigma$ has a dominated splitting. We characterize these sets
in terms of existence of invariant multicones, thus extending a 2-dimensional
result by Avila, Bochi, and Yoccoz. We give an example showing how these
multicones can fail to have convexity properties.


title: The Canis Major Star Forming Region

abstract:
  The shape of the main arc formed by the Canis Major clouds has been suggested
to result from a supernova explosion possibly triggering the recent star
formation activity. The presence of dozens of OB stars and reflection nebulae
forms the CMa OB1/R1 associations. More than a hundred emission line stars are
found in this region, including the famous Z CMa, a binary system containing a
Herbig Be star and a FUor companion. Several embedded infrared clusters with
different ages are associated with the CMa clouds. The main characteristics of
the region in terms of cloud structure, stellar content, age of associated
young clusters, distance, and X-ray emission are presented in this chapter.
Some of the arguments in favor and against the hypothesis of induced star
formation are discussed in the last section.


title:
Subaru Weak Lensing survey -- II: Multi-object Spectroscopy and Cluster
  Masses

abstract:
  We present the first results of a MOS campaign to follow up cluster
candidates located via weak lensing. Our main goals are to search for spatial
concentrations of galaxies that are plausible optical counterparts of the weak
lensing signals, and to determine the cluster redshifts from those of member
galaxies. Around each of 36 targeted cluster candidates, we obtain 15-32 galaxy
redshifts. For 28 of these targets, we confirm a secure cluster identification.
This includes three cases where two clusters at different redshifts are
projected along the same line-of-sight. In 6 of the 8 unconfirmed targets, we
find multiple small galaxy concentrations at different redshifts. In both the
remaining two targets, a single small galaxy concentration is found. We
evaluate the weak lensing mass of confirmed clusters. For a subsample of our
most cleanly measured clusters, we investigate the statistical relation between
their weak lensing mass and the velocity dispersion of their member galaxies,
comparing our sample with optically and X-ray selected samples from the
literature. Our lensing-selected clusters are consistent with
sigma_v=sigma_sis, with a similar scatter to the optically and X-ray selected
clusters. We thus find no evidence of selection bias compared to these other
techniques. We also derive an empirical relation between the cluster mass and
the galaxy velocity dispersion, which is in reasonable agreement with the
prediction of N-body simulations in the LCDM cosmology.


title:
The Optimal Spatially-Smoothed Source Patterns for the Pseudospectral
  Time-Domain Method

abstract:
  Spatially-smoothed sources are often utilized in the pseudospectral
time-domain (PSTD) method to suppress the associated aliasing errors to levels
as low as possible. In this work, the explicit conditions of the optimal source
patterns for these spanning sources are presented based on the fact that the
aliasing errors are mainly attributed to the high spatial-frequency parts of
the time-stepped source items and subsequently demonstrated to be exactly
corresponding to the normalized rows of Pascal's triangle. The outstanding
performance of these optimal sources is verified by the practical 1-D, 2-D and
3-D PSTD simulations and compared with that of non-optimal sources.


title: NGC 2362: The Terminus of Star Formation

abstract:
  NGC 2362 is a richly populated Galactic cluster, devoid of natal molecular
gas and dust. The cluster represents the final product of the star forming
process and hosts an unobscured and near-complete initial mass function. NGC
2362 is dominated by the O9 Ib multiple star, tau CMa, as well as several dozen
unevolved B-type stars. Distributed throughout the cluster are several hundred
suspected intermediate and low-mass pre-main sequence members. Various
post-main sequence evolutionary models have been used to infer an age of 5 Myr
for the one evolved member, tau CMa. These estimates are in close agreement
with the ages derived by fitting pre-main sequence isochrones to the
contracting, low-mass stellar population of the cluster. The extremely narrow
sequence of stars, which extends more than 9 mag in the optical color-magnitude
diagram, suggests that star formation within the cluster occurred rapidly and
coevally across the full mass spectrum. Ground-based near infrared and H-alpha
emission surveys of NGC 2362 concluded that most (~90%) of the low-mass members
have already dissipated their optically-thick, inner(< 1 AU) circumstellar
disks. Spitzer IRAC observations of the cluster have confirmed these results,
placing an upper limit on the primordial, optically thick disk fraction of the
cluster at 7(+/-)2%. The presence of circumstellar disks among candidate
members of NGC 2362 is also strongly mass-dependent, such that no stars more
massive than 1.2 Msun exhibit significant infrared excess shortward of 8
microns. The well-defined upper main sequence of NGC 2362, its large population
of low-mass stars, and the narrow age spread evident in the color-magnitude
diagram ensure its role as a standard model of cluster as well as stellar
evolution.


title:
How Cooper pairs vanish approaching the Mott insulator in
  Bi2Sr2CaCu2O8+d

abstract:
  The antiferromagnetic ground state of copper oxide Mott insulators is
achieved by localizing an electron at each copper atom in real space (r-space).
Removing a small fraction of these electrons (hole doping) transforms this
system into a superconducting fluid of delocalized Cooper pairs in momentum
space (k-space). During this transformation, two distinctive classes of
electronic excitations appear. At high energies, the enigmatic 'pseudogap'
excitations are found, whereas, at lower energies, Bogoliubov quasi-particles
-- the excitations resulting from the breaking of Cooper pairs -- should exist.
To explore this transformation, and to identify the two excitation types, we
have imaged the electronic structure of Bi2Sr2CaCu2O8+d in r-space and k-space
simultaneously. We find that although the low energy excitations are indeed
Bogoliubov quasi-particles, they occupy only a restricted region of k-space
that shrinks rapidly with diminishing hole density. Concomitantly, spectral
weight is transferred to higher energy r-space states that lack the
characteristics of excitations from delocalized Cooper pairs. Instead, these
states break translational and rotational symmetries locally at the atomic
scale in an energy independent fashion. We demonstrate that these unusual
r-space excitations are, in fact, the pseudogap states. Thus, as the Mott
insulating state is approached by decreasing the hole density, the delocalized
Cooper pairs vanish from k-space, to be replaced by locally translational- and
rotational-symmetry-breaking pseudogap states in r-space.


title: Exoplanet characterization with long slit spectroscopy

abstract:
  Extrasolar planets observation and characterization by high contrast imaging
instruments is set to be a very important subject in observational astronomy.
Dedicated instruments are being developed to achieve this goal with very high
efficiency. In particular, full spectroscopic characterization of low
temperature planetary companions is an extremely important milestone. We
present a new data analysis method for long slit spectroscopy (LSS) with
coronagraphy, which allows characterization of planetary companions of low
effective temperature. In a speckle-limited regime, this method allows an
accurate estimation and subtraction of the scattered starlight, to extract a
clean spectrum of the planetary companion. We performed intensive LSS
simulations with IDL/CAOS to obtain realistic spectra of low (R=35) and medium
(R=400) resolution in the J, H, and K bands. The simulated spectra were used to
test our method and estimate its performance in terms of contrast reduction and
extracted spectra quality. Our simulations are based on a software package
dedicated to the development of SPHERE, a second generation instrument for the
ESO-VLT. Our method allows a contrast reduction of 0.5 to 2.0 magnitudes
compared to the coronagraphic observations. For M0 and G0 stars located at 10
pc, we show that it would lead to the characterization of companions with Teff
of 600 K and 900 K respectively, at angular separations of 1.0 as. We also show
that errors in the wavelength calibration can produce significant errors in the
characterization, and must therefore be minimized as much as possible.


title:
A Disk of Young Stars at the Galactic Center as Determined by Individual
  Stellar Orbits

abstract:
  We present new proper motions from the 10 m Keck telescopes for a puzzling
population of massive, young stars located within 3.5" (0.14 pc) of the
supermassive black hole at the Galactic Center. Our proper motion measurements
have uncertainties of only 0.07 mas/yr (3 km/s), which is ~7 times better than
previous proper motion measurements for these stars, and enables us to measure
accelerations as low as 0.2 mas/yr^2 (7 km/s/yr). Using these measurements,
line-of-sight velocities from the literature, and 3D velocities for additional
young stars in the central parsec, we constrain the true orbit of each
individual star and directly test the hypothesis that the massive stars reside
in two stellar disks as has been previously proposed. Analysis of the stellar
orbits reveals only one of the previously proposed disks of young stars using a
method that is capable of detecting disks containing at least 7 stars. The
detected disk contains 50% of the young stars, is inclined by ~115 deg from the
plane of the sky, and is oriented at a position angle of ~100 deg East of
North. Additionally, the on-disk and off-disk populations have similar K-band
luminosity functions and radial distributions that decrease at larger projected
radii as \propto r^-2. The disk has an out-of-the-disk velocity dispersion of
28 +/- 6 km/s, which corresponds to a half-opening angle of 7 +/- 2 deg, and
several candidate disk members have eccentricities greater than 0.2. Our
findings suggest that the young stars may have formed in situ but in a more
complex geometry than a simple, thin circular disk.


title: Towards a definition of quantum integrability

abstract:
  We briefly review the most relevant aspects of complete integrability for
classical systems and identify those aspects which should be present in a
definition of quantum integrability.
  We show that a naive extension of classical concepts to the quantum framework
would not work because all infinite dimensional Hilbert spaces are unitarily
isomorphic and, as a consequence, it would not be easy to define degrees of
freedom. We argue that a geometrical formulation of quantum mechanics might
provide a way out.


title: Does the accreting millisecond pulsar XTE J1814-338 precess?

abstract:
  Precession in an accretion-powered pulsar is expected to produce
characteristic variations in the pulse properties. Assuming surface intensity
maps with one and two hotspots, we compute theoretically the periodic
modulation of the mean flux, pulse-phase residuals and fractional amplitudes of
the first and second harmonic of the pulse profiles. These quantities are
characterised in terms of their relative precession phase offsets. We then
search for these signatures in 37 days of X-ray timing data from the accreting
millisecond pulsar XTE J1814-338. We analyse a 12.2-d modulation observed
previously and show that it is consistent with a freely precessing neutron star
only if the inclination angle is < 0.1 degrees, an a priori unlikely
orientation. We conclude that if the observed flux variations are due to
precession, our model incompletely describes the relative precession phase
offsets (e.g. the surface intensity map is over-simplified). We are still able
to place an upper limit on \epsilon of 3.0 x 10^{-9} independently of our
model, and estimate the phase-independent tilt angle \theta; to lie roughly
between 5 and 10 degrees. On the other hand, if the observed flux variations
are not due to precession, the detected signal serves as a firm upper limit for
any underlying precession signal. We then place an upper limit on the product
\epsilon cos(\theta) of \leq 9.9 x 10^{-10}. The first scenario translates into
a maximum gravitational wave strain of 10^{-27} from XTE J1814-338 (assuming a
distance of 8 kpc), and a corresponding signal-to-noise ratio of \leq 10^{-3}
(for a 120 day integration time) for the advanced LIGO ground-based
gravitational wave detector.


title: Fluctuation-induced first-order transition in $p $-wave superconductors

abstract:
  The problem of a fluctuation-induced first-order transition is considered for
$p $-wave superconductors. Both an $\epsilon$-expansion about $d=4$ and a
large-$n$ expansion conclude that the transition for the physical case $n=6$ in
$d=3$ is of first order, as in the s-wave case.


title: Pion properties at finite density

abstract:
  In this talk, we report our recent work on the pion weak decay constant
(F_pi) and pion mass (m_pi) using the nonlocal chiral quark model with the
finite quark-number chemical potential (mu) taken into account. Considering the
breakdown of Lorentz invariance at finite density, the time and space
components are computed separately, and the corresponding results turn out to
be: F^t_pi = 82.96 MeV and F^s_pi = 80.29 MeV at mu_c ~ 320 MeV, respectively.
Using the in-medium Gell-Mann Oakes-Renner (GOR) relation, we show that the
pion mass increases by about 15% at mu_c.


title:
Formation and Transformation of Vector-Solitons in Two-Species
  Bose-Einstein Condensates with Tunable Interaction

abstract:
  Under a unified theory we investigate the formation of various types of
vector-solitons in two-species Bose-Einstein condensates with arbitrary
scattering lengths. We then show that by tuning the interaction parameter via
Feshbach resonance, transformation between different types of vector solitons
is possible. Our results open up new ways in the quantum control of
multi-species Bose-Einstein condensates.


title: Scaling law and stability for a noisy quantum system

abstract:
  We show that a scaling law exists for the near resonant dynamics of cold
kicked atoms in the presence of a randomly fluctuating pulse amplitude.
Analysis of a quasi-classical phase-space representation of the quantum system
with noise allows a new scaling law to be deduced. The scaling law and
associated stability are confirmed by comparison with quantum simulations and
experimental data.


title: On the Koszul Betti numbers in positive characteristic

abstract:
  We have observed a gap in one of the arguments in the main theorem. We choose
to withdraw the paper until we rectify the gap.


title: Ground-state energy of the unitary Fermi gas from the epsilon expansion

abstract:
  We update the ground-state energy ratio of unitary Fermi gas to
noninteracting Fermi gas (xi) from the epsilon expansion by including the
next-to-next-to-leading-order (NNLO) term near two spatial dimensions.
Interpolations of the NNLO epsilon expansions around four and two spatial
dimensions with the use of Pade approximants give xi=0.360+/-0.020 in three
dimensions with the uncertainty due to different interpolation functions. This
value is consistent with the previous interpolations of the NLO epsilon
expansions xi=0.377+/-0.014 in spite of the large NNLO corrections.


title:
Spatially Resolved Mapping of Local Polarization Dynamics in an Ergodic
  Phase of Ferroelectric Relaxor

abstract:
  Spatial variability of polarization relaxation kinetics in relaxor
ferroelectric 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 is studied using time-resolved
Piezoresponse Force Microscopy. Local relaxation attributed to the
reorientation of polar nanoregions is shown to follow stretched exponential
dependence, exp(-(t/tau)^beta), with beta~~0.4, much larger than the
macroscopic value determined from dielectric spectra (beta~~0.09). The spatial
inhomogeneity of relaxation time distributions with the presence of 100-200 nm
"fast" and "slow" regions is observed. The results are analyzed to map the
Vogel-Fulcher temperatures on the nanoscale.


title:
Time Delay in Robertson-McVittie Spacetime and its Application to
  Increase of Astronomical Unit

abstract:
  We investigated the light propagation by means of the Robertson-McVittie
solution which is considered to be the spacetime around the gravitating body
embedded in the FLRW (Friedmann-Lema{\^i}tre-Robertson-Walker) background
metric. We concentrated on the time delay and derived the correction terms with
respect to the Shapiro's formula. To relate with the actual observation and its
reduction process, we also took account of the time transformations; coordinate
time to proper one, and conversely, proper time to coordinate one. We applied
these results to the problem of increase of astronomical unit reported by
Krasinsky and Brumberg (2004). However, we found the influence of the
cosmological expansion on the light propagation does not give an explanation of
observed value, $d{\rm AU}/dt = 15 \pm 4$ [m/century] in the framework of
Robertson-McVittie metric.


title: The Kondo Lattice Model in Infinite Dimensions I. Formalism

abstract:
  A Green-function formalism for the Kondo lattice model is presented, which is
designed to be combined with the dynamical mean-field theory. With use of
Wick's theorem only for conduction electrons, dynamical quantities are
represented in terms of the t-matrix and its two-particle generalizations. By
taking the high-frequency limit of the t-matrix with respect to a part of the
fermion frequencies, one obtains dynamical correlation functions of localized
moments. Explicit examples of calculational steps are provided with use of the
continuous-time quantum Monte Carlo method.


title: Singly differential cross sections with exchange for Ps-fragmentation

abstract:
  Ps ionization in Ps-atom scattering is of fundamental importance. The singly
differential cross sections (SDCS) provides more accurate information to test a
theory than integrated or total ionization cross section since the averaging
over one parameter is not required. We evaluate the SDCS for Ps-ionization with
respect to the longitudinal energy distribution of the break-up positron and
electron in Ps-H and Ps-He scattering and compare them with the recently
available experimental and theoretical data.


title:
Controlling soliton interactions in Bose-Einstein condensates by
  synchronizing the Feshbach resonance and harmonic trap

abstract:
  We present how to control interactions between solitons, either bright or
dark, in Bose-Einstein condensates by synchronizing Feshbach resonance and
harmonic trap. Our results show that as long as the scattering length is to be
modulated in time via a changing magnetic field near the Feshbach resonance,
and the harmonic trapping frequencies are also modulated in time, exact
solutions of the one-dimensional nonlinear Schr\"{o}dinger equation can be
found in a general closed form, and interactions between two solitons are
modulated in detail in currently experimental conditions. We also propose
experimental protocols to observe the phenomena such as fusion, fission, warp,
oscillation, elastic collision in future experiments.


title: The Four-Loop Konishi in N=4 SYM

abstract:
  We present the result of a full direct component calculation for the planar
four-loop anomalous dimension of the Konishi operator in N =4 Supersymmetric
Yang-Mills theory. Our result confirms the results obtained from superfield
(arXiv:0712.3522, arXiv:0806.2095) and superstring (arXiv:0807.0399)
computations, which take into account finite size corrections to the all-loop
asymptotic Bethe ansatz for the integrable models describing the spectrum of
the anomalous dimensions of the gauge-invariant operators and the spectrum of
the string states in the framework of the gauge/string duality.


title: Algorithmic enumeration of ideal classes for quaternion orders

abstract:
  We provide algorithms to count and enumerate representatives of the (right)
ideal classes of an Eichler order in a quaternion algebra defined over a number
field. We analyze the run time of these algorithms and consider several related
problems, including the computation of two-sided ideal classes, isomorphism
classes of orders, connecting ideals for orders, and ideal principalization. We
conclude by giving the complete list of definite Eichler orders with class
number at most 2.


title:
Noncentrosymmetric Commensurate Magnetic Ordering of Multiferroic
  ErMn2O5

abstract:
  The non-centrosymmetric magnetic structure of ErMn$_2$O$_5$ has been shown to
be very similar to that of HoMn$_2$O$_5$ (Vecchini {\it et al.}, 2008 Phys.
Rev. B {\bf 77} 134434). The magnetic modulation at 25 K has propagation vector
$\vec k$=(1/2,0,1/4) and the symmetry imposes very few constraints on the
magnetic configurations allowed. Only by combining the results of bulk
magnetisation measurements, powder and single crystal neutron diffraction and
spherical neutron polarization analysis was it possible to distinguish clearly
between different models. The susceptibility measurements show that the erbium
magnetic moments are aligned parallel to the c-axis indicating strong
single-ion anisotropy. Spherical neutron polarimetry demonstrates the presence
of two unequally populated chirality domains in ErMn$_2$O$_5$ single crystals.
X-ray diffraction measurements on an ErMn$_2$O$_5$ powder using synchrotron
radiation show that the buckling angles of the Mn-O-Mn bond change below the
transition to the ferroelectric phase.


title: The Young Cluster and Star Forming Region NGC 2264

abstract:
  NGC 2264 is a young Galactic cluster and the dominant component of the Mon
OB1 association lying approximately 760 pc distant within the local spiral arm.
The cluster is hierarchically structured, with subclusters of suspected members
spread across several parsecs. Associated with the cluster is an extensive
molecular cloud complex spanning more than two degrees on the sky. Star
formation is ongoing within the region as evidenced by the presence of numerous
embedded clusters of protostars, molecular outflows, and Herbig-Haro objects.
The stellar population of NGC 2264 is dominated by the O7 V multiple star, S
Mon, and several dozen B-type zero-age main sequence stars. X-ray imaging
surveys, H-alpha emission surveys, and photometric variability studies have
identified more than 600 intermediate and low-mass members distributed
throughout the molecular cloud complex, but concentrated within two densely
populated areas between S Mon and the Cone Nebula. Estimates for the total
stellar population of the cluster range as high as 1000 members and limited
deep photometric surveys have identified 230 substellar mass candidates. The
median age of NGC 2264 is estimated to be 3 Myr, but an apparent age dispersion
of at least 5 Myr can be inferred from the broadened sequence of suspected
members. Infrared and millimeter observations of the cluster have identified
two prominent sites of star formation activity centered near NGC 2264 IRS1, a
deeply embedded early-type star, and IRS2, a star forming core and associated
protostellar cluster. Given its relative proximity, well-defined stellar
population, and low foreground extinction, the cluster will remain a prime
candidate for star formation studies throughout the foreseeable future.


title: Soft Modes and Relaxor Ferroelectrics

abstract:
  Relaxor ferroelectrics are difficult to study and understand. The experiment
shows that at low energy scattering there is an acoustic mode, an optic mode,
dynamic quasi-elastic scattering and strictly elastic scattering as well as
Bragg peaks at the zone centre. We have studied the scattering using the TASP
spectrometer at PSI and have analysed the data using a model with interactions
between the different components particularly to determine the properties of
the elastic scattering. The quasi-elastic scattering begins to become
significant at the Burns temperature of 620 K. It steadily increases in
intensity on cooling reaching a maximum at ~400 K. Below this temperature the
strictly elastic scattering begins to increase and shows a broadened line shape
characteristic of crystals in a random applied field. We show that all the
results obtained from PMN for the elastic scattering are consistent with the
crystal having a random field transition at ~400 K. We have obtained similar
results for PMN-PT and PZN-PT suggesting that random fields of the nano-regions
also play an important role in these materials.


title: Accelerometer using atomic waves for space applications

abstract:
  The techniques of laser cooling combined with atom interferometry make
possible the realization of very sensitive and accurate inertial sensors like
gyroscopes or accelerometers. Besides earth-based developments, the use of
these techniques in space should provide extremely high sensitivity for
research in fundamental physics, Earth's observation and exploration of the
solar system.


title: Minimal hypersurfaces in $\HH^n \times \R$, total curvature and index

abstract:
  In this paper, we consider minimal hypersurfaces in the product space
$\mathbb{H}^n \times \mathbb{R}$. We begin by studying examples of rotation
hypersurfaces and hypersurfaces invariant under hyperbolic translations. We
then consider minimal hypersurfaces with finite total curvature. This
assumption implies that the corresponding curvature goes to zero uniformly at
infinity. We show that surfaces with finite total intrinsic curvature have
finite index. The converse statement is not true as shown by our examples which
also serve as useful barriers.


title:
A high order purely frequency-based harmonic balance formulation for
  continuation of periodic solutions

abstract:
  Combinig the harmonic balance method (HBM) and a continuation method is a
well-known technique to follow the periodic solutions of dynamical systems when
a control parameter is varied. However, since deriving the algebraic system
containing the Fourier coefficients can be a highly cumbersome procedure, the
classical HBM is often limited to polynomial (quadratic and cubic)
nonlinearities and/or a few harmonics. Several variations on the classical HBM,
such as the incremental HBM or the alternating frequency/time domain HBM, have
been presented in the literature to overcome this shortcoming. Here, we present
an alternative approach that can be applied to a very large class of dynamical
systems (autonomous or forced) with smooth equations. The main idea is to
systematically recast the dynamical system in quadratic polynomial form before
applying the HBM. Once the equations have been rendered quadratic, it becomes
obvious to derive the algebraic system and solve it by the so-called ANM
continuation technique. Several classical examples are presented to illustrate
the use of this numerical approach.


title: On the Pfister Number of Quadratic Forms

abstract:
  The generic quadratic form of even dimension n with trivial discriminant over
an arbitrary field of characteristic different from 2 containing a square root
of -1 can be written in the Witt ring as a sum of 2-fold Pfister forms using
n-2 terms and not less. The number of 2-fold Pfister forms needed to express a
quadratic form of dimension 6 with trivial discriminant is determined in
various cases.


title: Tetrahedra on deformed spheres and integral group cohomology

abstract:
  We show that for every injective continuous map f: S^2 --> R^3 there are four
distinct points in the image of f such that the convex hull is a tetrahedron
with the property that two opposite edges have the same length and the other
four edges are also of equal length. This result represents a partial result
for the topological Borsuk problem for R^3. Our proof of the geometrical claim,
via Fadell-Husseini index theory, provides an instance where arguments based on
group cohomology with integer coefficients yield results that cannot be
accessed using only field coefficients.


title: Directed polymer in random environment and last passage percolation

abstract:
  The sequence of random probability measures $\nu_n$ that gives a path of
length $n$, $\unsur{n}$ times the sum of the random weights collected along the
paths, is shown to satisfy a large deviations principle with good rate function
the Legendre transform of the free energy of the associated directed polymer in
a random environment. Consequences on the asymptotics of the typical number of
paths whose collected weight is above a fixed proportion are then drawn.


title: Radio observations of Jupiter-family comets

abstract:
  Radio observations from decimetric to submillimetric wavelengths are now a
basic tool for the investigation of comets. Spectroscopic observations allow us
i) to monitor the gas production rate of the comets, by directly observing the
water molecule, or by observing secondary products (e.g., the OH radical) or
minor species (e.g., HCN); ii) to investigate the chemical composition of
comets; iii) to probe the physical conditions of cometary atmospheres: kinetic
temperature and expansion velocity. Continuum observations probe large-size
dust particles and (for the largest objects) cometary nuclei. Comets are
classified from their orbital characteristics into two separate classes: i)
nearly-isotropic, mainly long-period comets and ii) ecliptic, short-period
comets, the so-called Jupiter-family comets. These two classes apparently come
from two different reservoirs, respectively the Oort cloud and the
trans-Neptunian scattered disc. Due to their different history and - possibly -
their different origin, they may have different chemical and physical
properties that are worth being investigated. The present article reviews the
contribution of radio observations to our knowledge of the Jupiter-family
comets (JFCs). The difficulty of such a study is the commonly low gas and dust
productions of these comets. Long-period, nearly-isotropic comets from the Oort
cloud are better known from Earth-based observations. On the other hand,
Jupiter-family comets are more easily accessed by space missions. However,
unique opportunities to observe Jupiter-family comets are offered when these
objects come by chance close to the Earth. About a dozen JFCs were successfully
observed by radio techniques up to now. No obvious evidence for different
properties between JFCs and other families of comets is found.


title: Optimal State Discrimination in General Probabilistic Theories

abstract:
  We investigate a state discrimination problem in operationally the most
general framework to use a probability, including both classical, quantum
theories, and more. In this wide framework, introducing closely related family
of ensembles (which we call a {\it Helstrom family of ensembles}) with the
problem, we provide a geometrical method to find an optimal measurement for
state discrimination by means of Bayesian strategy. We illustrate our method in
2-level quantum systems and in a probabilistic model with square-state space to
reproduce e.g., the optimal success probabilities for binary state
discrimination and $N$ numbers of symmetric quantum states. The existences of
families of ensembles in binary cases are shown both in classical and quantum
theories in any generic cases.


title: Entropy of Self-Gravitating Systems from Holst's Lagrangian

abstract:
  We shall prove here that conservation laws from Holst's Lagrangian, often
used in LQG, do not agree with the corresponding conservation laws in standard
GR. Nevertheless, these differences vanish on-shell, i.e. along solutions, so
that they eventually define the same classical conserved quantities.
Accordingly, they define in particular the same entropy of solutions, and the
standard law S=A/4 is reproduced for systems described by Holst's Lagragian.
This provides the classical support to the computation usually done in LQG for
the entropy of black holes which is in turn used to fix the Barbero-Immirzi
parameter.


title: Suzaku Observations of SGR 1900+14 and SGR 1806-20

abstract:
  Spectral and timing studies of Suzaku ToO observations of two SGRs, 1900+14
and 1806-20, are presented. The X-ray quiescent emission spectra were well
fitted by a two blackbody function or a blackbody plus a power law model. The
non-thermal hard component discovered by INTEGRAL was detected by the PIN
diodes and its spectrum was reproduced by the power law model reported by
INTEGRAL. The XIS detected periodicity P = 5.1998+/-0.0002 s for SGR 1900+14
and P = 7.6022+/-0.0007 s for SGR 1806-20. The pulsed fraction was related to
the burst activity for SGR 1900+14.


title:
The star ingesting luminosity of intermediate mass black holes in
  globular clusters

abstract:
  The dynamics of stars in the inner regions of nearby globular clusters (GCs)
such as G1 indicate the presence of central concentrated dark masses, and one
would like to know whether these are indeed intermediate mass black holes
(IMBHs). As the number of surrounding stars, and their motions, are roughly
known, the capture rate can be estimated; the question then arises of whether
the apparent quiescence of the nuclei of these GCs is compatible with the
IMBH's presence. The role of debris from disrupted stars in activating
quiescent nuclei of GCs is studied here employing three-dimensional
hydrodynamics simulations. It is argued that when individual stars are
disrupted, the bulk of the debris would be swallowed or expelled rapidly
compared with the interval between successive disruptions. Only a small
fraction of the tightly bound mass is likely to be swallowed, yielding
radiation with high efficiency, the surplus being expelled in a
radiation-driven wind. A transient (predominantly of soft X-ray emission)
signal could persist steadily with L ~ L_Edd =10^{41}(M_h/10^3M_sun) erg/s for
at most tens of years; thereafter the flare would rapidly fade. While the
infall rate declines as t^{-5/3}, some material may be stored for a longer time
in an accretion disk. The IMBH luminosity could then remain as high as L_X >
10^{39} erg/s for several hundreds of years after disruption. In a given
object, this ultraluminous X-ray activity would have a duty cycle of order
10^{-4}. Quiescent GCs, those with IMBHs now starved of fuel, should greatly
outnumber active ones; observational constraints would not then be stringent
until we had observed enough candidates to constitute a proper ensemble
average.(abridged)


title:
Prevalence of the adiabatic exchange-correlation potential approximation
  in time-dependent density functional theory

abstract:
  Time-dependent (TD) density functional theory (TDDFT) promises a numerically
tractable account of many-body electron dynamics provided good simple
approximations are developed for the exchange-correlation (XC) potential
functional (XCPF). The theory is usually applied within the adiabatic XCPF
approximation, appropriate for slowly varying TD driving fields. As the
frequency and strength of these fields grows, it is widely held that memory
effects kick in and the eligibility of the adiabatic XCPF approximation
deteriorates irreversibly. We point out however that when a finite system of
electrons in its ground-state is gradually exposed to a very a high-frequency
and eventually ultra-strong homogeneous electric field, the adiabatic XCPF
approximation is in fact rigorously applicable. This result not only helps to
explain recent numerical results for a 1D-helium atom subject to a strong
linearly-polarized laser pulse (Thiel et al, Phys. Rev. Lett. 100, 153004,
(2008)) but also shows that it is applicable to any number of electrons and in
full 3D.


title:
Three-Qubit Operators, the Split Cayley Hexagon of Order Two and Black
  Holes

abstract:
  The set of 63 real generalized Pauli matrices of three-qubits can be factored
into two subsets of 35 symmetric and 28 antisymmetric elements. This splitting
is shown to be completely embodied in the properties of the Fano plane; the
elements of the former set being in a bijective correspondence with the 7
points, 7 lines and 21 flags, whereas those of the latter set having their
counterparts in 28 anti-flags of the plane. This representation naturally
extends to the one in terms of the split Cayley hexagon of order two. 63 points
of the hexagon split into 9 orbits of 7 points (operators) each under the
action of an automorphism of order 7. 63 lines of the hexagon carry three
points each and represent the triples of operators such that the product of any
two gives, up to a sign, the third one. Since this hexagon admits a full
embedding in a projective 5-space over GF(2), the 35 symmetric operators are
also found to answer to the points of a Klein quadric in such space. The 28
antisymmetric matrices can be associated with the 28 vertices of the Coxeter
graph, one of two distinguished subgraphs of the hexagon. The PSL_{2}(7)
subgroup of the automorphism group of the hexagon is discussed in detail and
the Coxeter sub-geometry is found to be intricately related to the
E_7-symmetric black-hole entropy formula in string theory. It is also
conjectured that the full geometry/symmetry of the hexagon should manifest
itself in the corresponding black-hole solutions. Finally, an intriguing
analogy with the case of Hopf sphere fibrations and a link with coding theory
are briefly mentioned.


title:
Catalogue of 12CO(J=1-0) and 13CO(J=1-0) Molecular Clouds in the Carina
  Flare Supershell

abstract:
  We present a catalogue of 12CO(J=1-0) and 13CO(J=1-0) molecular clouds in the
spatio-velocity range of the Carina Flare supershell, GSH 287+04-17. The data
cover a region of ~66 square degrees and were taken with the NANTEN 4m
telescope, at spatial and velocity resolutions of 2.6' and 0.1 km/s.
Decomposition of the emission results in the identification of 156 12CO clouds
and 60 13CO clouds, for which we provide observational and physical parameters.
Previous work suggests the majority of the detected mass forms part of a
comoving molecular cloud complex that is physically associated with the
expanding shell. The cloud internal velocity dispersions, degree of
virialization and size-linewidth relations are found to be consistent with
those of other Galactic samples. However, the vertical distribution is heavily
skewed towards high-altitudes. The robust association of high-z molecular
clouds with a known supershell provides some observational backing for the
theory that expanding shells contribute to the support of a high-altitude
molecular layer.


title: Repeatable quantum memory channels

abstract:
  Within the framework of quantum memory channels we introduce the notion of
repeatability of quantum channels. In particular, a quantum channel is called
repeatable if there exist a memory device implementing the same channel on each
individual input. We show that random unitary channels can be implemented in a
repeatable fashion, whereas the nonunital channels cannot.


title: Gibbs Sampling, Exponential Families and Orthogonal Polynomials

abstract:
  We give families of examples where sharp rates of convergence to stationarity
of the widely used Gibbs sampler are available. The examples involve standard
exponential families and their conjugate priors. In each case, the transition
operator is explicitly diagonalizable with classical orthogonal polynomials as
eigenfunctions.


title:
Macroscopic models of local field potentials and the apparent 1/f noise
  in brain activity

abstract:
  The power spectrum of local field potentials (LFPs) has been reported to
scale as the inverse of the frequency, but the origin of this "1/f noise" is at
present unclear. Macroscopic measurements in cortical tissue demonstrated that
electric conductivity (as well as permittivity) is frequency dependent, while
other measurements failed to evidence any dependence on frequency. In the
present paper, we propose a model of the genesis of LFPs which accounts for the
above data and contradictions. Starting from first principles (Maxwell
equations), we introduce a macroscopic formalism in which macroscopic
measurements are naturally incorporated, and also examine different physical
causes for the frequency dependence. We suggest that ionic diffusion primes
over electric field effects, and is responsible for the frequency dependence.
This explains the contradictory observations, and also reproduces the 1/f power
spectral structure of LFPs, as well as more complex frequency scaling. Finally,
we suggest a measurement method to reveal the frequency dependence of current
propagation in biological tissue, and which could be used to directly test the
predictions of the present formalism.


title: Noise driven unlimited population growth

abstract:
  Demographic noise causes unlimited population growth in a broad class of
models which, without noise, would predict a stable finite population. We study
this effect on the example of a stochastic birth-death model which includes
immigration, binary reproduction and death. The unlimited population growth
proceeds as an exponentially slow decay of a metastable probability
distribution (MPD) of the population. We develop a systematic WKB theory,
complemented by the van Kampen system size expansion, for the MPD and for the
decay time. Important signatures of the MPD is a power-law tail (such that all
the distribution moments, except the zeroth one, diverge) and the presence in
the solution of two different WKB modes.


title: Comment: Gibbs Sampling, Exponential Families and Orthogonal Polynomials

abstract:
  Comment on ``Gibbs Sampling, Exponential Families and Orthogonal
Polynomials'' [arXiv:0808.3852]


title:
Comment: Gibbs Sampling, Exponential Families, and Orthogonal
  Polynomials

abstract:
  Comment on ``Gibbs Sampling, Exponential Families, and Orthogonal
Polynomials'' [arXiv:0808.3852]


title:
Covariate Balance in Simple, Stratified and Clustered Comparative
  Studies

abstract:
  In randomized experiments, treatment and control groups should be roughly the
same--balanced--in their distributions of pretreatment variables. But how
nearly so? Can descriptive comparisons meaningfully be paired with significance
tests? If so, should there be several such tests, one for each pretreatment
variable, or should there be a single, omnibus test? Could such a test be
engineered to give easily computed $p$-values that are reliable in samples of
moderate size, or would simulation be needed for reliable calibration? What new
concerns are introduced by random assignment of clusters? Which tests of
balance would be optimal? To address these questions, Fisher's randomization
inference is applied to the question of balance. Its application suggests the
reversal of published conclusions about two studies, one clinical and the other
a field experiment in political participation.


title: Hyperbolic Deformation on Quantum Lattice Hamiltonians

abstract:
  A group of non-uniform quantum lattice Hamiltonians in one dimension is
introduced, which is related to the hyperbolic $1 + 1$-dimensional space. The
Hamiltonians contain only nearest neighbor interactions whose strength is
proportional to $\cosh j \lambda$, where $j$ is the lattice index and where
$\lambda \ge 0$ is a deformation parameter. In the limit $\lambda \to 0$ the
Hamiltonians become uniform. Spacial translation of the deformed Hamiltonians
is induced by the corner Hamiltonians. As a simple example, we investigate the
ground state of the deformed $S = 1/2$ Heisenberg spin chain by use of the
density matrix renormalization group (DMRG) method. It is shown that the ground
state is dimerized when $\lambda$ is finite. Spin correlation function show
exponential decay, and the boundary effect decreases with increasing $\lambda$.


title: Comment: Lancaster Probabilities and Gibbs Sampling

abstract: Comment on ``Lancaster Probabilities and Gibbs Sampling'' [arXiv:0808.3852]


title:
Non-additive properties of finite 1D Ising chains with long-range
  interactions

abstract:
  We study the statistical properties of Ising spin chains with finite
(although arbitrary large) range of interaction between the elements. We
examine mesoscopic subsystems (fragments of an Ising chain) with the lengths
comparable with the interaction range. The equivalence of the Ising chains and
the multi-step Markov sequences is used for calculating different non-additive
statistical quantities of a chain and its fragments. In particular, we study
the variance of fluctuating magnetization of fragments, magnetization of the
chain in the external magnetic field, etc. Asymptotical expressions for the
non-additive energy and entropy of the mesoscopic fragments are derived in the
limiting cases of weak and strong interactions.


title: Comment: On Random Scan Gibbs Samplers

abstract: Comment on ``On Random Scan Gibbs Samplers'' [arXiv:0808.3852]


title: Multipartite Entanglement and Global Information

abstract:
  We investigate the entanglement properties of pure quantum states describing
$n$ qubits. We characterize all multipartite states which can be maximally
entangled to local auxiliary systems using controlled operations. A state has
this property iff one can construct out of it an orthonormal basis by applying
independent local unitary operations. This implies that those states can be
used to encode locally the maximum amount of $n$ bits. Examples of these states
are the so--called stabilizer states, which are used for quantum error
correction and one--way quantum computing. We give a simple characterization of
these states and construct a complete set of commuting unitary observables
which characterize the state uniquely. Furthermore we show how these states can
be prepared and discuss their applications.


title: Parallel in Time Simulation of Multiscale Stochastic Chemical Kinetics

abstract:
  A version of the time-parallel algorithm parareal is analyzed and applied to
stochastic models in chemical kinetics. A fast predictor at the macroscopic
scale (evaluated in serial) is available in the form of the usual reaction rate
equations. A stochastic simulation algorithm is used to obtain an exact
realization of the process at the mesoscopic scale (in parallel).
  The underlying stochastic description is a jump process driven by the Poisson
measure. A convergence result in this arguably difficult setting is established
suggesting that a homogenization of the solution is advantageous. We devise a
simple but highly general such technique.
  Three numerical experiments on models representative to the field of
computational systems biology illustrate the method. For non-stiff problems, it
is shown that the method is able to quickly converge even when stochastic
effects are present. For stiff problems we are instead able to obtain fast
convergence to a homogenized solution.
  Overall, the method builds an attractive bridge between on the one hand,
macroscopic deterministic scales and, on the other hand, mesoscopic stochastic
ones. This construction is clearly possible to apply also to stochastic models
within other fields.


title:
Rejoinder: Gibbs Sampling, Exponential Families and Orthogonal
  Polynomials

abstract:
  We are thankful to the discussants for their hard, interesting work. The main
purpose of our paper was to give reasonably sharp rates of convergence for some
simple examples of the Gibbs sampler. We chose examples from expository
accounts where direct use of available techniques gave practically useless
answers. Careful treatment of these simple examples grew into bivariate
modeling and Lancaster families. Since bounding rates of convergence is our
primary focus, let us begin there. [arXiv:0808.3852]


title:
Integrability of the Gross-Pitaevskii Equation with Feshbach Resonance
  management

abstract:
  In this paper we study the integrability of a class of Gross-Pitaevskii
equations managed by Feshbach resonance in an expulsive parabolic external
potential. By using WTC test, we find a condition under which the
Gross-Pitaevskii equation is completely integrable. Under the present model,
this integrability condition is completely consistent with that proposed by
Serkin, Hasegawa, and Belyaeva [V. N. Serkin et al., Phys. Rev. Lett. 98,
074102 (2007)]. Furthermore, this integrability can also be explicitly shown by
a transformation, which can convert the Gross-Pitaevskii equation into the
well-known standard nonlinear Schr\"odinger equation. By this transformation,
each exact solution of the standard nonlinear Schr\"odinger equation can be
converted into that of the Gross-Pitaevskii equation, which builds a
systematical connection between the canonical solitons and the so-called
nonautonomous ones. The finding of this transformation has a significant
contribution to understanding the essential properties of the nonautonomous
solitions and the dynamics of the Bose-Einstein condensates by using the
Feshbach resonance technique.


title: O-minimal homotopy and generalized (co)homology

abstract:
  This article explains and extends semialgebraic homotopy theory (developed by
H. Delfs and M. Knebusch) to o-minimal homotopy theory (over a field). The
homotopy category of definable CW-complexes is equivalent to the homotopy
category of topological CW-complexes (with continuous mappings). If the theory
of the o-minimal expansion of a field is bounded, then these categories are
equivalent to the homotopy category of weakly definable spaces. Similar facts
hold for decreasing systems of spaces. As a result, generalized homology and
cohomology theories on pointed weak polytopes uniquely correspond (up to an
isomorphism) to the known topological generalized homology and cohomology
theories on pointed CW-complexes.


title: Minimal Dark Matter predictions and the PAMELA positron excess

abstract:
  We present Minimal Dark Matter and its univocal predictions for Dark Matter
observables. During the idm2008 conference, PAMELA presented preliminary
results showing an excess in the positron fraction: we find a good agreement,
with a modest astrophysical boost factor.


title: QED calculation of transition probabilities in two-electron ions

abstract:
  Accurate QED calculation of transition probabilities for the low-lying
two-electron configurations of multicharged ions is presented. The calculation
is performed for the nondegenerate states $(1s2s) 3S1$, $(1s2p_{3/2}) 3P2$ ($M
1$ and $M 2$ transitions, respectively) and for the quasidegenerate states
$(1s2p) 1P1$, $(1s2p) 3P1$ ($E 1$ transitions) decaying to the ground state
$(1s1s) 1S0$. Two-electron ions with nuclear charge numbers $Z=10-92$ are
considered. The line profile approach is employed for the description of the
process in multicharged ions within the framework of QED.


title:
Ground states of 2d +-J Ising spin glasses via stationary Fokker-Planck
  sampling

abstract:
  We investigate the performance of the recently proposed stationary
Fokker-Planck sampling method considering a combinatorial optimization problem
from statistical physics. The algorithmic procedure relies upon the numerical
solution of a linear second order differential equation that depends on a
diffusion-like parameter D. We apply it to the problem of finding ground states
of 2d Ising spin glasses for the +-J-Model. We consider square lattices with
side length up to L=24 with two different types of boundary conditions and
compare the results to those obtained by exact methods.
  A particular value of D is found that yields an optimal performance of the
algorithm. We compare this optimal value of D to a percolation transition,
which occurs when studying the connected clusters of spins flipped by the
algorithm. Nevertheless, even for moderate lattice sizes, the algorithm has
more and more problems to find the exact ground states. This means that the
approach, at least in its standard form, seems to be inferior to other
approaches like parallel tempering.


title: Logic Integer Programming Models for Signaling Networks

abstract:
  We propose a static and a dynamic approach to model biological signaling
networks, and show how each can be used to answer relevant biological
questions. For this we use the two different mathematical tools of
Propositional Logic and Integer Programming. The power of discrete mathematics
for handling qualitative as well as quantitative data has so far not been
exploited in Molecular Biology, which is mostly driven by experimental
research, relying on first-order or statistical models. The arising logic
statements and integer programs are analyzed and can be solved with standard
software. For a restricted class of problems the logic models reduce to a
polynomial-time solvable satisfiability algorithm. Additionally, a more dynamic
model enables enumeration of possible time resolutions in poly-logarithmic
time. Computational experiments are included.


title:
Effects of Zn and Ni substitution on the Cu-spin dynamics and
  superconductivity in La_2-x_Sr_x_Cu_1-y_(Zn,Ni)_y_O_4_ with x=0.15-0.20
  studied by the muon spin relaxation and magnetic susceptibility

abstract:
  We have investigated effects of Zn and Ni on the Cu-spin dynamics and
superconductivity from the zero-field muon-spin-relaxation (ZF-muSR) and
magnetic-susceptibility, chi, measurements for
La_2-x_Sr_x_Cu_1-y_(Zn,Ni)_y_O_4_ with x=0.15-0.20, changing y up to 0.10 in
fine step. In the optimally doped x=0.15, it has been concluded that the
formation of a magnetic order requires a larger amount of Ni than that of Zn,
which is similar to our previous results of x=0.13. From the estimation of
volume fractions of superconducting (SC) and magnetic regions, it has been
found for x=0.15 that the SC region is in rough correspondence to the region
where Cu spins fluctuate fast beyond the muSR frequency window for both Zn- and
Ni-substituted samples. According to the stripe model, it follows that, even
for x=0.15, the dynamical stripe correlations of spins and holes are pinned and
localized around Zn and Ni, leading to the formation of the static stripe order
and the suppression of superconductivity. These may indicate an importance of
the dynamical stripe in the appearance of the high-T_c_ superconductivity in
the hole-doped cuprates. In the overdoped regime of x=0.18 and 0.20, on the
other hand, the SC region seems to be in rough correspondence to the region
where Cu spins fluctuate fast beyond the muSR frequency window, though it
appears that the Cu-spin dynamics and superconductivity are affected by the
phase separation into SC and normal-state regions.


title:
Salt-specific stability and denaturation of a short salt-bridge forming
  alpha-helix

abstract:
  The structure of a single alanine-based Ace-AEAAAKEAAAKA-Nme peptide in
explicit aqueous electrolyte solutions (NaCl, KCl, NaI, and KF) at large salt
concentrations (3-4 M) is investigated using 1 microsecond molecular dynamics
(MD) computer simulations. The peptide displays 71 alpha-helical structure
without salt and destabilizes with the addition of NaCl in agreement with
experiments of a somewhat longer version. It is mainly stabilized by direct and
indirect (i+4)EK salt bridges between the Lys and Glu side chains and a
concomitant backbone shielding mechanism. NaI is found to be a stronger
denaturant than NaCl, while the potassium salts hardly show influence.
Investigation of the molecular structures reveals that consistent with recent
experiments Na+ has a much stronger affinity to side chain carboxylates and
backbone carbonyls than K+, thereby weakening salt bridges and secondary
structure hydrogen bonds. At the same time the large I- has a considerable
affinity to the nonpolar alanine in line with recent observations of a large
propensity of I- to adsorb to simple hydrophobes, and thereby 'assists' Na+ in
its destabilizing action. In the denatured states of the peptide novel
long-lived (10-20 ns) 'loop'-configurations are observed in which single Na+
ions and water molecules are hydrogen-bonded to multiple backbone carbonyls. In
an attempt to analyze the denaturation behavior within the preferential
interaction formalism, we find indeed that for the strongest denaturant, NaI,
the protein is least hydrated. Additionally, a possible indication for protein
denaturation might be a preferential solvation of the first solvation shell of
the peptide backbone by the destabilizing cosolute (sodium).


title: Notes on the UK Non-Native Organism Risk Assessment Scheme

abstract:
  In 2004, the UK Government's Department for Environment, Food and Rural
Affairs commissioned research with the aim of developing a scheme for assessing
the risks posed to species, habitats and ecosystems in the UK by non-native
organisms. The outcome was the UK Non-Native Organism Risk Assessment Scheme.
Unfortunately, the mathematical basis of the procedure for summarising risks
deployed in the Risk Assessment Scheme, as outlined in Baker et al. (2008) and
described in more detail in the Risk Assessment Scheme's User Manual, contains
several analytical errors. These errors are outlined in the notes that follow.


title: Delocalization-Localization Transition due to Anharmonicity

abstract:
  Analytical and numerical calculations for a reduced Fermi-Pasta-Ulam chain
demonstrate that energy localization does not require more than one conserved
quantity. Clear evidence for the existence of a sharp
delocalization-localization transition at a critical amplitude is given.
Approaching the critical amplitude from above and below, diverging time scales
occur. Above the critical amplitude, the energy packet converges towards a
discrete breather. Nevertheless, ballistic energy transportation is present,
demonstrating that its existence does not necessarily imply delocalization.


title: On a Hamiltonian form of an elliptic spin Ruijsenaars-Schneider system

abstract:
  An explicit expression of a Hamiltonian form of an elliptic spin
Ruijsenaars-Schneider is found in the case of 2 particles using
Krichever-Phong's universal symplectic form. In the rational limit it coincides
with a Poisson bracket found by Arutyunov and Frolov.


title: A purely dipolar quantum gas

abstract:
  We report on experiments exploring the physics of dipolar quantum gases using
a Chromium Bose-Einstein condensate (BEC). By means of a Feshbach resonance, it
is possible to reduce the effects of short range interactions and reach a
regime where the physics is governed by the long-range, anisotropic
dipole-dipole interaction between the large ($6 \mu_{\rm B}$) magnetic moments
of Chromium atoms. Several dramatic effects of the dipolar interaction are
observed: the usual inversion of ellipticity of the condensate during time-of
flight is inhibited, the stability of the dipolar gas depends strongly on the
trap geometry, and the explosion following the collapse of an unstable dipolar
condensate displays d-wave like features.


title: Embeddings of C*-surfaces into weighted projective spaces

abstract:
  Let V be a normal affine surface which admits a C*- and a C+-action. In this
note we show that in many cases V can be embedded as a principal Zariski open
subset into a hypersurface of a weighted projective space. In particular, we
recover a result of D. Daigle and P. Russell.


title: Measuring Outer Disk Warps with Optical Spectroscopy

abstract:
  Warps in the outer gaseous disks of galaxies are a ubiquitous phenomenon, but
it is unclear what generates them. One theory is that warps are generated
internally through spontaneous bending instabilities. Other theories suggest
that they result from the interaction of the outer disk with accreting
extragalactic material. In this case, we expect to find cases where the
circular velocity of the warp gas is poorly correlated with the rotational
velocity of the galaxy disk at the same radius. Optical spectroscopy presents
itself as an interesting alternative to 21-cm observations for testing this
prediction, because (i) separating the kinematics of the warp from those of the
disk requires a spatial resolution that is higher than what is achieved at 21
cm at low HI column density; (ii) optical spectroscopy also provides important
information on star formation rates, gas excitation, and chemical abundances,
which provide clues to the origin of the gas in warps. We present here
preliminary results of a study of the kinematics of gas in the outer-disk warps
of seven edge-on galaxies, using multi-hour VLT/FORS2 spectroscopy.


title: Higher Rank Wavelets

abstract:
  A theory of higher rank multiresolution analysis is given in the setting of
abelian multiscalings. This theory enables the construction, from a higher rank
MRA, of finite wavelet sets whose multidilations have translates forming an
orthonormal basis in $L^2(\bR^d)$. While tensor products of uniscaled MRAs
provide simple examples we construct many nonseparable higher rank wavelets. In
particular we construct Latin square wavelets as rank 2 variants of Haar
wavelets. Also we construct nonseparable scaling functions for rank 2 variants
of Meyer wavelet scaling functions, and we construct the associated
nonseparable wavelets with compactly supported Fourier transforms. On the other
hand we show that compactly supported scaling functions for biscaled MRAs are
necessarily separable.


title: The security of Ping-Pong protocol

abstract:
  Ping-Pong protocol is a type of quantum key distribution which makes use of
two entangled photons in the EPR state. Its security is based on the
randomization of the operations that Alice performs on the travel photon
(qubit), and on the anti-correlation between the two photons in the EPR state.
In this paper, we study the security of this protocol against some known
quantum attacks, and present a scheme that may enhance its security to some
degree.


title: Counting Hexagonal Patches and Independent Sets in Circle Graphs

abstract:
  A hexagonal patch is a plane graph in which inner faces have length 6, inner
vertices have degree 3, and boundary vertices have degree 2 or 3. We consider
the following counting problem: given a sequence of twos and threes, how many
hexagonal patches exist with this degree sequence along the outer face? This
problem is motivated by the study of benzenoid hydrocarbons and fullerenes in
computational chemistry. We give the first polynomial time algorithm for this
problem. We show that it can be reduced to counting maximum independent sets in
circle graphs, and give a simple and fast algorithm for this problem.


title: A chain morphism for Adams operations on rational algebraic K-theory

abstract:
  For any regular noetherian scheme X and every k>0, we define a chain morphism
between two chain complexes whose homology with rational coefficients is
isomorphic to the algebraic K-groups of X tensored by the field of rational
numbers. It is shown that these morphisms induce in homology the Adams
operations defined by Gillet and Soule or the ones defined by Grayson.


title: Stars and gas in the Medusa merger

abstract:
  The Medusa (NGC 4194) is a well-studied nearby galaxy with the disturbed
appearance of a merger and evidence for ongoing star formation. In order to
test whether it could be the result of an interaction between a gas-rich
disk-like galaxy and a larger elliptical, we have carried out optical and radio
observations of the stars and the gas in the Medusa, and performed $N$-body
numerical simulations of the evolution of such a system. We used the Nordic
Optical Telescope to obtain a deep V-band image and the Westerbork Radio
Synthesis Telescope to map the large-scale distribution and kinematics of
atomic hydrogen. A single HI tail was found to the South of the Medusa with a
projected length of 56 kpc (5') and a gas mass of 7* 10^8 M_sun, thus
harbouring about one third of the total HI mass of the system. HI was also
detected in absorption toward the continuum in the center. HI was detected in a
small nearby galaxy to the North-West of the Medusa at a projected distance of
91 kpc. It is, however, unlikely that this galaxy has had a significant
influence on the evolution of the Medusa. The simulations of the slightly
prograde infall of a gas-rich disk galaxy on an larger, four time more massive
elliptical (spherical) galaxy reproduce most of the observed features of the
Medusa.Thus, the Medusa is an ideal object to study the merger-induced star
formation contribution from the small galaxy of a minor merger.


title: The Complexity of Reasoning for Fragments of Default Logic

abstract:
  Default logic was introduced by Reiter in 1980. In 1992, Gottlob classified
the complexity of the extension existence problem for propositional default
logic as $\SigmaPtwo$-complete, and the complexity of the credulous and
skeptical reasoning problem as SigmaP2-complete, resp. PiP2-complete.
Additionally, he investigated restrictions on the default rules, i.e.,
semi-normal default rules. Selman made in 1992 a similar approach with
disjunction-free and unary default rules. In this paper we systematically
restrict the set of allowed propositional connectives. We give a complete
complexity classification for all sets of Boolean functions in the meaning of
Post's lattice for all three common decision problems for propositional default
logic. We show that the complexity is a hexachotomy (SigmaP2-, DeltaP2-, NP-,
P-, NL-complete, trivial) for the extension existence problem, while for the
credulous and skeptical reasoning problem we obtain similar classifications
without trivial cases.


title:
Fractionally Quantized Cooper Pair Stair Case in Superconducting Quantum
  Dots

abstract:
  We study clean superconducting quantum dots (SQD) and also site dependent
Josephson couplings, on site charging energies and the intersite interactions
in presence of gate voltage. We predict the existence of different fractionally
quantized Cooper pair stair case with many interesting physical properties. The
appearance of stair case is not only due to the Coulomb blocked phenomena but
also for the site dependent Josephson couplings. We also explain physically the
absence of other fractionally quantized Cooper pair stair case. The physics of
fractionally quantized Cooper pair stair case has close resemblance with the
fractionally quantized magnetization plateau of a spin chain system under a
magnetic field.


title: Stress dependent thermal pressurization of a fluid-saturated rock

abstract:
  Temperature increase in saturated porous materials under undrained conditions
leads to thermal pressurization of the pore fluid due to the discrepancy
between the thermal expansion coefficients of the pore fluid and of the solid
matrix. This increase in the pore fluid pressure induces a reduction of the
effective mean stress and can lead to shear failure or hydraulic fracturing.
The equations governing the phenomenon of thermal pressurization are presented
and this phenomenon is studied experimentally for a saturated granular rock in
an undrained heating test under constant isotropic stress. Careful analysis of
the effect of mechanical and thermal deformation of the drainage and pressure
measurement system is performed and a correction of the measured pore pressure
is introduced. The test results are modelled using a non-linear
thermo-poro-elastic constitutive model of the granular rock with emphasis on
the stress-dependent character of the rock compressibility. The effects of
stress and temperature on thermal pressurization observed in the tests are
correctly reproduced by the model.


title:
The Multiwavelength Picture of Star Formation in the Very Young Open
  Cluster NGC6383

abstract:
  We review the properties of the very young (2 Myr) open cluster NGC6383. The
cluster is dominated by the massive binary HD159176 (O7V + O7V). The distance
to NGC6383 is consistently found to be 1.3 +- 0.1 kpc and the average reddening
is determined to be E(B-V) = 0.32 +- 0.02. Several pre-main sequence candidates
have been identified using different criteria relying on the detection of
emission lines, infrared excesses, photometric variability and X-ray emission.


title:
New Model System for a One-Dimensional Electron Liquid: Self-Organized
  Atomic Gold Chains on Ge(001)

abstract:
  Unique electronic properties of self-organized Au atom chains on Ge(001) in
novel c(8x2) long-range order are revealed by scanning tunneling microscopy.
Along the nanowires an exceptionally narrow conduction path exists which is
virtually decoupled from the substrate. It is laterally confined to the
ultimate limit of single atom dimension, and is strictly separated from its
neighbors, as not previously reported. The resulting tunneling conductivity
shows a dramatic inhomogeneity of two orders of magnitude. The atom chains thus
represent an outstandingly close approach to a one-dimensional electron liquid.


title: Open architecture for multilingual parallel texts

abstract:
  Multilingual parallel texts (abbreviated to parallel texts) are linguistic
versions of the same content ("translations"); e.g., the Maastricht Treaty in
English and Spanish are parallel texts. This document is about creating an open
architecture for the whole Authoring, Translation and Publishing Chain
(ATP-chain) for the processing of parallel texts.


title: A deep look into the cores of young clusters I. sigma-Orionis

abstract:
  Nearby young clusters are privileged places to study the star formation
history. Over the last decade, the sigma-Orionis cluster has been a prime
location for the study of young very low mass stars, substellar and isolated
planetary mass objects and the determination of the initial mass function.
  To extend previous studies of this association to its core, we searched for
ultracool members and new multiple systems within the 1.5'x1.5' central region
of the cluster.
  We obtained deep multi-conjugate adaptive optics (MCAO) images of the core of
the sigma-Orionis cluster with the prototype MCAO facility MAD at the VLT using
the H and Ks filters. These images allow us to reach Delta H~5mag as close as
0.2" on a typical source with H=14.5mag. These images were complemented by
archival SofI Ks-band images and Spitzer IRAC and MIPS mid-infrared images.
  We report the detection of 2 new visual multiple systems, one being a
candidate binary proplyd and the other one a low mass companion to the massive
star sigma Ori E. Of the 36 sources detected in the images, 25 have a H-band
luminosity lower than the expected planetary mass limit for members, and H-Ks
color consistent with the latest theoretical isochrones. Nine objects have
additional Spitzer photometry and spectral energy distribution consistent with
them being cluster members. One of them has a spectral energy distribution from
H to 3.6micron consistent with that of a 5.5 MJup cluster member. Complementary
NTT/SofI and Spitzer photometry allow us to confirm the nature and membership
of two L-dwarf planetary mass candidates.


title: Coupled two-component atomic gas in an optical lattice

abstract:
  We present an ab initio study of the ground state of an ideal coupled
two-component gas of ultracold atoms in a one dimensional optical lattice,
either bosons or fermions. Due to the internal two-level structure of the
atoms, the Brillouin zone is twice as large as imposed by the periodicity of
the lattice potential. This is reflected in the Bloch dispersion curves, where
the energy bands regularly possess several local minima. As a consequence, when
the system parameters are tuned across a resonance condition, a non-zero
temperature phase transition occurs which arises from an interplay between
internal and kinetic atomic energies. For fermions, this phase transition is of
topological character since the structure of the Fermi surface is changed
across the critical value. It is shown that these phenomena are also expected
to occur for two and three dimensional optical lattices.


title: Essential arity gap of Boolean functions

abstract:
  We investigate the Boolean functions with essential arity gap 2. We use Full
Conjunctive Normal Forms instead of Zhegalkin's polynomials, which allow us to
simplify the proofs and to obtain several combinatorial results, concerning the
Boolean functions with a given arity gap.


title: Quasi-analytische Zerlegungen

abstract:
  The leaves in singular holomorphic foliation theory are examples of
quasi-analytic layers. In the first part of our publication we are concerned
with a theory of these subjects. A quasi-analytic decomposition of a complex
manifold is a decomposition into pairwise disjoint connected quasi-analytic
layers. These are holomorphic foliations in the sense of P. Stefan and K.
Spallek. A very different but more usual conception of holomorphic foliations
is develloped by P. Baum and R. Bott. It is based on holomorphic sheaf theory.
In the second part we study the relation between quasi-analytic decompositions
and singular holomorphic foliations in the sense of Baum and Bott.


title:
Influence of Disorder Strength on Phase Field Models of Interfacial
  Growth

abstract:
  We study the influence of disorder strength on the interface roughening
process in a phase-field model with locally conserved dynamics. We consider two
cases where the mobility coefficient multiplying the locally conserved current
is either constant throughout the system (the two-sided model) or becomes zero
in the phase into which the interface advances (one-sided model). In the limit
of weak disorder, both models are completely equivalent and can reproduce the
physical process of a fluid diffusively invading a porous media, where
super-rough scaling of the interface fluctuations occurs. On the other hand,
increasing disorder causes the scaling properties to change to intrinsic
anomalous scaling. In the limit of strong disorder this behavior prevails for
the one-sided model, whereas for the two-sided case, nucleation of domains in
front of the invading front are observed.


title: Kinematics of the H2O masers at the centre of the PN K3-35

abstract:
  We have studied the kinematics traced by the water masers located at the
centre of the planetary nebula (PN) K3-35, using data from previous Very Large
Array (VLA) observations. An analysis of the spatial distribution and
line-of-sight velocities of the maser spots allows us to identify typical
patterns of a rotating and expanding ring in the position-velocity diagrams,
according to our kinematical model. We find that the distribution of the masers
is compatible with tracing a circular ring with a ~0.021 arcsec (~100 AU)
radius, observed with an inclination angle with respect to the line of sight of
55 degrees. We derive expansion and rotation velocities of 1.4 and 3.1 km/s,
respectively. The orientation of the ring projected on the plane of the sky, at
PA 158 degrees, is almost orthogonal to the direction of the innermost region
of the jet observed in K3-35, suggesting the presence of a disc or torus that
may be related to the collimation of the outflow.


title:
Experimental manifestation of the breakpoint region in the
  current-voltage characteristics of intrinsic Josephson junctions

abstract:
  The experimental evidence of the breakpoint on the current-voltage
characteristics (IVCs) of the stacks of intrinsic Josephson junctions (IJJs) is
presented. The influence of the capacitive coupling on the IVCs of
Bi$_2$Sr$_2$CaCu$_2$O$_y$ IJJs has been investigated. At 4.2 K, clear
breakpoint region is observed on the branches in the IVCs. It is found that the
hysteresis observed on the IVC is suppressed due to the coupling compared with
that expected from the McCumber parameter. Measurements agree well with the
results obtained by the theoretical model.


title: New composite models of partially ionized protoplanetary disks

abstract:
  We study an accretion disk in which three different regions may coexist: MHD
turbulent regions, dead zones and gravitationally unstable regions. Although
the dead zones are stable, there is some transport due to the Reynolds stress
associated with waves emitted from the turbulent layers. We model the transport
in each of the different regions by its own $\alpha$ parameter, this being 10
to $10^{3}$ times smaller in dead zones than in active layers. In
gravitationally unstable regions, $\alpha$ is determined by the fact that the
disk self-adjusts to a state of marginal stability. We construct steady-state
models of such disks. We find that for uniform mass flow, the disk has to be
more massive, hotter and thicker at the radii where there is a dead zone. In
disks in which the dead zone is very massive, gravitational instabilities are
present. Whether such models are realistic or not depends on whether
hydrodynamical fluctuations driven by the turbulent layers can penetrate all
the way inside the dead zone. This may be more easily achieved when the ratio
of the mass of the active layer to that of the dead zone is relatively large,
which in our models corresponds to $\alpha$ in the dead zone being about 10% of
$\alpha$ in the active layers. If the disk is at some stage of its evolution
not in steady-state, then the surface density will evolve toward the
steady-state solution. However, if $\alpha$ in the dead zone is much smaller
than in the active zone, the timescale for the parts of the disk beyond a few
AU to reach steady-state may become longer than the disk lifetime. Steady-state
disks with dead zones are a more favorable environment for planet formation
than standard disks, since the dead zone is typically 10 times more massive
than a corresponding turbulent zone at the same location.


title: Nature and Nurture in Dark Matter Halos

abstract:
  Cosmological simulations consistently predict specific properties of dark
matter halos, but these have not yet led to a physical understanding that is
generally accepted. This is especially true for the central regions of these
structures. Recently two major themes have emerged. In one, the dark matter
halo is primarily a result of the sequential accretion of primordial structure
(ie `Nature'); while in the other, dynamical relaxation (ie `Nurture')
dominates at least in the central regions. Some relaxation is however required
in either mechanism. In this paper we accept the recently established
scale-free sub-structure of halos as an essential part of both mechanisms.
Consequently; a simple model for the central relaxation based on a self-similar
cascade of tidal interactions, is contrasted with a model based on the
accretion of adiabatically self-similar, primordial structure. We conclude that
a weak form of this relaxation is present in the simulations, but that is
normally described as the radial orbit instability.


title:
Critiquing Variational Theories of the Anderson-Hubbard Model:
  Real-Space Self-Consistent Hartree-Fock Solutions

abstract:
  A simple and commonly employed approximate technique with which one can
examine spatially disordered systems when strong electronic correlations are
present is based on the use of real-space unrestricted self-consistent
Hartree-Fock wave functions. In such an approach the disorder is treated
exactly while the correlations are treated approximately. In this report we
critique the success of this approximation by making comparisons between such
solutions and the exact wave functions for the Anderson-Hubbard model. Due to
the sizes of the complete Hilbert spaces for these problems, the comparisons
are restricted to small one-dimensional chains, up to ten sites, and a 4x4
two-dimensional cluster, and at 1/2 filling these Hilbert spaces contain about
63,500 and 166 million states, respectively. We have completed these
calculations both at and away from 1/2 filling. This approximation is based on
a variational approach which minimizes the Hartree-Fock energy, and we have
completed comparisons of the exact and Hartree-Fock energies. However, in order
to assess the success of this approximation in reproducing ground-state
correlations we have completed comparisons of the local charge and spin
correlations, including the calculation of the overlap of the Hartree-Fock wave
functions with those of the exact solutions. We find that this approximation
reproduces the local charge densities to quite a high accuracy, but that the
local spin correlations, as represented by < S_i . S_j >, are not as well
represented. In addition to these comparisons, we discuss the properties of the
spin degrees of freedom in the HF approximation, and where in the
disorder-interaction phase diagram such physics may be important.


title: Giant magnetic anisotropy of the bulk antiferromagnets IrMn and IrMn3

abstract:
  Theoretical predictions of the magnetic anisotropy of antiferromagnetic
materials are demanding due to a lack of experimental techniques which are
capable of a direct measurement of this quantity. At the same time it is highly
significant due to the use of antiferromagnetic components in magneto-resistive
sensor devices where the stability of the antiferromagnet is of upmost
relevance. We perform an ab-initio study of the ordered phases of IrMn and
IrMn3, the most widely used industrial antiferromagnets. Calculating the form
and the strength of the magnetic anisotropy allows the construction of an
effective spin model, which is tested against experimental measurements
regarding the magnetic ground state and the Neel temperature. Our most
important result is the extremely strong second order anisotropy for IrMn3
appearing in its frustrated triangular magnetic ground state, a surprising fact
since the ordered L12 phase has a cubic symmetry. We explain this large
anisotropy by the fact that cubic symmetry is locally broken for each of the
three Mn sub-lattices.


title:
Consistency of ground state and spectroscopic measurements on flux
  qubits

abstract:
  We compare the results of ground state and spectroscopic measurements carried
out on superconducting flux qubits which are effective two-level quantum
systems. For a single qubit and for two coupled qubits we show excellent
agreement between the parameters of the pseudospin Hamiltonian found using both
methods. We argue, that by making use of the ground state measurements the
Hamiltonian of N coupled flux qubits can be reconstructed as well at
temperatures smaller than the energy level separation. Such a reconstruction of
a many-qubit Hamiltonian can be useful for future quantum information
processing devices.