title: Relativistic Three-Body Scattering in a First Order Faddeev Formulation

abstract:
  Relativistic Faddeev equations for three-body scattering at arbitrary
energies are solved in first order in the two-body transition operator in terms
of momentum vectors without employing a partial wave decomposition.
Relativistic invariance is incorporated within the framework of Poincar{\'e}
invariant quantum mechanics. Based on a Malfliet-Tjon type interaction,
observables for elastic and breakup scattering are calculated and compared to
the nonrelativistic ones.


title:
Existence of periodic solutions for enzyme-catalysed reactions with
  periodic substrate input

abstract:
  Considering a basic enzyme-catalysed reaction, in which the rate of input of
the substrate varies periodically in time, we give a necessary and sufficient
condition for the existence of a periodic solution of the reaction equations.
The proof employs the Leray-Schauder degree, applied to an appropriately
constructed homotopy.


title: Image Decomposition of Barred Galaxies and AGN Hosts

abstract:
  I present the results of multi-component decomposition of V and R broadband
images of a sample of 17 nearby galaxies, most of them hosting bars and active
galactic nuclei. I use BUDDA v2.1 to produce the fits, allowing to include bars
and AGN in the models. A comparison with previous results from the literature
shows a fairly good agreement. It is found that the axial ratio of bars, as
measured from ellipse fits, can be severely underestimated if the galaxy
axisymmetric component is relatively luminous. Thus, reliable bar axial ratios
can only be determined by taking into account the contributions of bulge and
disc to the light distribution in the galaxy image. Through a number of tests,
I show that neglecting bars when modelling barred galaxies can result in a
overestimation of the bulge-to-total luminosity ratio of a factor of two.
Similar effects result when bright, type 1 AGN are not considered in the
models. By artificially redshifting the images, I show that the structural
parameters of more distant galaxies can in general be reliably retrieved
through image fitting, at least up to the point where the physical spatial
resolution is ~ 1.5 Kpc. This exercise shows that disc parameters are
particularly robust, but bulge parameters are prone to errors if its effective
radius is small compared to the seeing radius, and might suffer from systematic
effects. In this low resolution regime, the effects of ignoring bars are still
present, but AGN light is smeared out. I briefly discuss the consequences of
these results to studies of the structural properties of galaxies, in
particular on the stellar mass budget in the local universe. With reasonable
assumptions, it is possible to show that the stellar content in bars can be
similar to that in classical bulges and elliptical galaxies. (Abridged)


title: Hilbert's Fifth Problem for Local Groups

abstract:
  We solve Hilbert's fifth problem for local groups: every locally euclidean
local group is locally isomorphic to a Lie group. Jacoby claimed a proof of
this in 1957, but this proof is seriously flawed. We use methods from
nonstandard analysis and model our solution after a treatment of Hilbert's
fifth problem for global groups by Hirschfeld.


title:
Commuting elements in conjugacy classes: An application of Hall's
  Marriage Theorem

abstract:
  Let G be a finite group. Define a relation ~ on the conjugacy classes of G by
setting C ~ D if there are representatives c \in C and d \in D such that cd =
dc. In the case where G has a normal subgroup H such that G/H is cyclic, two
theorems are proved concerning the distribution, between cosets of H, of pairs
of conjugacy classes of G related by ~. One of the proofs involves an
interesting application of the famous Marriage Theorem of Philip Hall.
  The paper concludes by discussing some aspects of these theorems and of the
relation ~ in the particular cases of symmetric and general linear groups, and
by mentioning an open question related to Frobenius groups.


title: Radio Continuum and Star Formation in CO-rich Early Type Galaxies

abstract:
  In this paper we present new high resolution VLA 1.4 GHz radio continuum
observations of five FIR bright CO-rich early-type galaxies and two dwarf
early-type galaxies. The position on the radio-FIR correlation combined with
striking agreements in morphology between high resolution CO and radio maps
show that the radio continuum is associated with star formation in at least
four of the eight galaxies. The average star formation rate for the sample
galaxies detected in radio is approximately 2 solar masses per year. There is
no evidence of a luminous AGN in any of our sample galaxies. We estimate Toomre
Q values and find that the gas disks may well be gravitationally unstable,
consistent with the above evidence for star formation activity. The radio
continuum emission thus corroborates other recent suggestions that star
formation in early type galaxies may not be uncommon.


title: Detecting dark energy with wavelets on the sphere

abstract:
  Dark energy dominates the energy density of our Universe, yet we know very
little about its nature and origin. Although strong evidence in support of dark
energy is provided by the cosmic microwave background, the relic radiation of
the Big Bang, in conjunction with either observations of supernovae or of the
large scale structure of the Universe, the verification of dark energy by
independent physical phenomena is of considerable interest. We review works
that, through a wavelet analysis on the sphere, independently verify the
existence of dark energy by detecting the integrated Sachs-Wolfe effect. The
effectiveness of a wavelet analysis on the sphere is demonstrated by the highly
statistically significant detections of dark energy that are made. Moreover,
the detection is used to constrain properties of dark energy. A coherent
picture of dark energy is obtained, adding further support to the now well
established cosmological concordance model that describes our Universe.


title:
The effect of non-Gaussian curvature perturbations on the formation of
  primordial black holes

abstract:
  This paper explores the consequences of non-Gaussian cosmological
perturbations for the formation of primordial black holes (PBHs). A
non-Gaussian probability distribution function (PDF) of curvature perturbations
is presented with an explicit contribution from the three-point correlation
function to linear order. The consequences of this non-Gaussian PDF for the
large perturbations that form PBHs are then studied. Using the observational
limits for the non-Gaussian parameter $f_{NL}$, new bounds to the mean
amplitude of curvature perturbations are derived in the range of scales
relevant for PBH formation.


title:
X-ray Anomalous Scattering of Diluted Magnetic Oxide Semiconductors:
  Possible Evidence of Lattice Deformation for High Temperature Ferromagnetism

abstract:
  We have examined whether the Co ions crystallographically substitute on the
Ti sites in rutile and anatase Ti_{1-x}$Co$_{x}$O$_{2-delta}$ thin films that
exhibit room-temperature ferromagnetism. Intensities of the x-ray Bragg
reflection from the films were measured around the $K$-absorption-edge of Co.
If the Co ions randomly substitute on the Ti sites, the intensity should
exhibit an anomaly due to the anomalous dispersion of the atomic scattering
factor of Co. However, none of the anatase and rutile samples did exhibit an
anomaly, unambiguously showing that the Co ions in
Ti$_{1-x}$Co$_{x}$O$_{2-delta}$ are not exactly located at the Ti sites of
TiO$_2$. The absence of the anomaly is probably caused by a significant
deformation of the local structure around Co due to the oxygen vacancy. We have
applied the same method to paramagnetic Zn$_{1-x}$Co$_{x}$O thin films and
obtained direct evidence that the Co ions are indeed substituted on the Zn
sites.


title: A Null Test of the Cosmological Constant

abstract:
  We provide a consistency relation between cosmological observables in general
relativity with the cosmological constant. Breaking of this relation at any
redshift would imply the breakdown of the hypothesis of the cosmological
constant as an explanation of the current acceleration of the universe.


title:
Two energy scales and close relationship between the pseudogap and
  superconductivity in underdoped cuprate superconductors

abstract:
  By measuring the low temperature specific heat, the low energy quasi-particle
excitation has been derived and analyzed in systematically doped
La$_{2-x}$Sr$_{x}$CuO$_{4}$ single crystals. The Volovik's relation predicted
for a d-wave superconductor has been well demonstrated in wide doping regime,
showing a robust evidence for the d-wave pairing symmetry. Furthermore the
nodal gap slope $v_\Delta$ of the superconducting gap is derived and is found
to follow the same doping dependence of the pseudogap obtained from ARPES and
tunnelling measurement. This strongly suggests a close relationship between the
pseudogap and superconductivity. Taking the entropy conservation into account,
we argue that the ground state of the pseudogap phase should have Fermi arcs
with finite density of states at zero K, and the transport data show that it
behaves like an insulator due to probably weak localization. A nodal metal
picture for the pseudogap phase cannot interpret the data. Based on the Fermi
arc picture for the pseudogap phase it is found that the superconducting energy
scale or $T_c$ in underdoped regime is governed by both the maximum gap and the
spectral weight from the Fermi arcs. This suggests that there are two energy
scales: superconducting energy scale and the pseudogap. The superconductivity
may be formed by the condensation of Fermi arc quasiparticles through pairing
by exchanging virtue bosons.


title: Graph Annotations in Modeling Complex Network Topologies

abstract:
  The coarsest approximation of the structure of a complex network, such as the
Internet, is a simple undirected unweighted graph. This approximation, however,
loses too much detail. In reality, objects represented by vertices and edges in
such a graph possess some non-trivial internal structure that varies across and
differentiates among distinct types of links or nodes. In this work, we
abstract such additional information as network annotations. We introduce a
network topology modeling framework that treats annotations as an extended
correlation profile of a network. Assuming we have this profile measured for a
given network, we present an algorithm to rescale it in order to construct
networks of varying size that still reproduce the original measured annotation
profile.
  Using this methodology, we accurately capture the network properties
essential for realistic simulations of network applications and protocols, or
any other simulations involving complex network topologies, including modeling
and simulation of network evolution. We apply our approach to the Autonomous
System (AS) topology of the Internet annotated with business relationships
between ASs. This topology captures the large-scale structure of the Internet.
In depth understanding of this structure and tools to model it are cornerstones
of research on future Internet architectures and designs. We find that our
techniques are able to accurately capture the structure of annotation
correlations within this topology, thus reproducing a number of its important
properties in synthetically-generated random graphs.

categories: cs.NI cond-mat.dis-nn physics.data-an physics.soc-ph


title: Generically finite morphisms and formal neighborhoods of arcs

abstract:
  We show that given a dominant morphism between two smooth varieties of the
same dimension, the induced morphism between the formal neighborhoods of two
arcs on these varieties is a closed embedding, of codimension given by the
order of vanishing along the ramification subscheme.


title:
Radiation Testing of Consumer High-Speed LSI Chips for the Next Space
  VLBI Mission, VSOP-2

abstract:
  We performed two types of radiation testing on high-speed LSI chips to test
their suitability for use in wideband observations by the Japanese next space
VLBI mission, VSOP-2. In the total ionization dose experiment we monitored
autocorrelation spectra which were taken with irradiated LSI chips and the
source current at intervals up to 1,000 hours from the ionization dose, but we
could not see any change of these features for the chips irradiated with dose
rates expected in the VSOP-2 mission. In the single event effect experiment, we
monitored the cross correlation phase and power spectra between the data from
radiated and non-radiated devices, and the source current during the
irradiation of heavy-ions. We observed a few tens of single event upsets as
discrete delay jumps for each LSI. We estimated the occurrence rate of single
events in space as between once a few days to once a month. No single event
latch-up was seen in any of the LSIs. These results show that the tested LSIs
have sufficient tolerance to the environment for space VLBI observations.


title:
Aluminium substitution induced superstructures in Mg1-xAlxB2 (x = 0.0 to
  0.50): An X-ray diffraction study

abstract:
  The physical property characterization of Al doped Mg1-xAlxB2 system with x =
0.0 to 0.50 is reported. The results related to phase formation, structural
transition, resistivity R(T) and magnetization M(T) measurements are discussed
in detail. It is shown that the addition of electrons to MgB2 through Al
results in loss of superconductivity. Also seen is a structural transition
associated with the collapse of boron layers reflected by the continuous
decrease in the c parameter. The main emphasis in this paper is on slow scan
X-ray diffraction (XRD) results, which confirm the existence of a
superstructure along the c-direction for the x = 0.50 sample. The appearance of
some additional peaks, viz. [103], [004], [104] and [112], results in doubling
of the lattice parameter along the c-axis. This possibly indicates the
alternative ordering of Al and Mg in MgAlB4 separated by hexagonal boron layers
but still maintaining the same hexagonal AlB2 type structure.


title: Role of Carbon in Enhancing the Performance of MgB2 superconductor

abstract:
  The enhancement of the critical current density (Jc(H)) of carbon and
nano-SiC doped MgB2 is presented and compared. The upper critical field (Hc2)
being determined from resistivity under magnetic field experiments is though
improved for both C substitution and nano-SiC addition the same is more
pronounced for the former. In MgB2-xCx carbon is substituted for boron that
induces disorder in the boron network and acts as internal pinning centres. The
optimal Jc(H) values are obtained for x = 0.1 sample . In case of nano-SiC
doped in MgB2, the Jc(H) improves more profoundly and two simultaneous
mechanisms seems responsible to this enhancement. Highly reactive nano-SiC
releases free carbon atom, which gets easily incorporated into the MgB2 lattice
to act as intrinsic pinning centres. Further enhancement is observed for higher
nano-SiC concentrations, where the un-reacted components serve as additional
extrinsic pinning centres.


title: A domain-wall-brane-localized standard model

abstract:
  We sketch an SU(5) bulk model in 4+1-dimensions that plausibly produces an
effective 3+1-dimensional standard model dynamically-localized on a domain
wall.


title: Effect of PVA doping on flux pinning in Bulk MgB2

abstract:
  The synthesis and characterization of PVA (Poly Vinyl Acetate) doped bulk
MgB2 superconductor is reported here. PVA is used as a Carbon source. PVA
doping effects made two distinguishable contributions: first enhancement of Jc
field performance and second an increase in Hc2 value, both because of carbon
incorporation into MgB2 crystal lattice. The susceptibility measurement reveals
that Tc decreased from 37 to 36 K. Lattice parameter a decreased from 3.085 A
to 3.081 A due to the partial substitution of Carbon at Boron site. PVA doped
sample exhibited the Jc values greater than 10^5 A/cm2 at 5 & 10 K at low
fields; which is almost 3 times higher than the pure one, while at high fields
the Jc is increased by an order of magnitude in comparison to pure MgB2. From
R(T)H measurements we found higher Tc values under magnetic field for doped
sample; indicating an increase in Hc2. Also the magnetization measurements
exhibited a significant enhancement in Hirr value. The improved performance of
PVA doped MgB2 can be attributed to the substitution of carbon at boron site in
parent MgB2 and the resulting impact on the carrier density and impurity
scattering. The improved flux pinning behavior could easily be seen from
reduced flux pinning force plots.


title:
Complementary Pair Density Wave and d-wave Checkerboard Order in High
  Temperature Superconductors

abstract:
  The competing orders in the particle-particle (P-P) channel and the
particle-hole (P-H) channel have been proposed separately to explain the
pseudogap physics in cuprates. By solving the Bogoliubov-deGennes equation
self-consistently, we show that there is a general complementary connection
between the d-wave checkerboard order (DWCB) in the particle-hole (P-H) channel
and the pair density wave order (PDW) in the particle-particle (P-P) channel. A
small pair density localization generates DWCB and PDW orders simultaneously.
The result suggests that suppressing superconductivity locally or globally
through phase fluctuation should induce both orders in underdoped cuprates. The
presence of both DWCB and PDW orders with $4a \times 4a$ periodicity can
explain the checkerboard modulation observed in FT-STS from STM and the
puzzling dichotomy between the nodal and antinodal regions as well as the
characteristic features such as non-dispersive Fermi arc in the pseudogap
state.


title:
Tuning the Competing magnetic interactions in RTiGe (R = Tb, Er)
  Compounds and tailoring the Magnetocaloric effect

abstract:
  The tetragonal layered compounds TbTiGe and ErTiGe order
antiferromagnetically at 276 K and 39 K, respectively. Partial substitution of
Mo for Ti in these two compounds modifies the magnetic interactions giving rise
to a ferromagnetic ground state which results in an enhanced magnetocaloric
effect. The magnetic entropy change in ErTi0.85Mo0.15Ge for a magnetic field
change of 5 T is ~10.5 J/kg/K against ~0.8 J/kg/K for ErTiGe in the vicinity of
the magnetic transition. Thus, magnetocaloric properties of such layered
materials may be tunable by suitable chemical substitutions.


title: Superconductivity in zigzag CuO chains

abstract:
  Superconductivity has recently been discovered in
Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$ with a maximum $T_c$ of about 15K.
Since the CuO planes in this material are believed to be insulating, it has
been proposed that the superconductivity occurs in the double (or zigzag) CuO
chain layer. On phenomenological grounds, we propose a theoretical
interpretation of the experimental results in terms of a new phase for the
zigzag chain, labelled by C$_1$S$_{3/2}$. This phase has a gap for some of the
relative spin and charge modes but no total spin gap, and can have a divergent
superconducting susceptibility for repulsive interactions. A microscopic model
for the zigzag CuO chain is proposed, and on the basis of density matrix
renormalization group (DMRG) and bosonization studies of this model, we adduce
evidence that supports our proposal.


title: Do single photons tunnel faster than light?

abstract:
  Experiments done in the early 1990's produced a surprising result: that
single photons pass through a photonic tunnel barrier with a group velocity
faster than the vacuum speed of light. Subsequent experiments with classical
pulses have also revealed apparent superluminal group velocities as well as
tunneling times that saturate with barrier length, a phenomenon known as the
Hartman effect. In this paper we show that the measured delays are in fact
cavity lifetimes as opposed to transit times. This interpretation resolves the
Hartman paradox and shows that tunneling is not superluminal as widely
believed.


title: Rapid planetesimal formation in turbulent circumstellar discs

abstract:
  The initial stages of planet formation in circumstellar gas discs proceed via
dust grains that collide and build up larger and larger bodies (Safronov 1969).
How this process continues from metre-sized boulders to kilometre-scale
planetesimals is a major unsolved problem (Dominik et al. 2007): boulders stick
together poorly (Benz 2000), and spiral into the protostar in a few hundred
orbits due to a head wind from the slower rotating gas (Weidenschilling 1977).
Gravitational collapse of the solid component has been suggested to overcome
this barrier (Safronov 1969, Goldreich & Ward 1973, Youdin & Shu 2002). Even
low levels of turbulence, however, inhibit sedimentation of solids to a
sufficiently dense midplane layer (Weidenschilling & Cuzzi 1993, Dominik et al.
2007), but turbulence must be present to explain observed gas accretion in
protostellar discs (Hartmann 1998). Here we report the discovery of efficient
gravitational collapse of boulders in locally overdense regions in the
midplane. The boulders concentrate initially in transient high pressures in the
turbulent gas (Johansen, Klahr, & Henning 2006), and these concentrations are
augmented a further order of magnitude by a streaming instability (Youdin &
Goodman 2005, Johansen, Henning, & Klahr 2006, Johansen & Youdin 2007) driven
by the relative flow of gas and solids. We find that gravitationally bound
clusters form with masses comparable to dwarf planets and containing a
distribution of boulder sizes. Gravitational collapse happens much faster than
radial drift, offering a possible path to planetesimal formation in accreting
circumstellar discs.


title: The brachistochrone problem in open quantum systems

abstract:
  Recently, the quantum brachistochrone problem is discussed in the literature
by using non-Hermitian Hamilton operators of different type. Here, it is
demonstrated that the passage time is tunable in realistic open quantum systems
due to the biorthogonality of the eigenfunctions of the non-Hermitian Hamilton
operator. As an example, the numerical results obtained by Bulgakov et al. for
the transmission through microwave cavities of different shape are analyzed
from the point of view of the brachistochrone problem. The passage time is
shortened in the crossover from the weak-coupling to the strong-coupling regime
where the resonance states overlap and many branch points (exceptional points)
in the complex plane exist. The effect can {\it not} be described in the
framework of standard quantum mechanics with Hermitian Hamilton operator and
consideration of $S$ matrix poles.


title: Measurement of the CKM angle phi2 (alpha)

abstract:
  We present recent measurements of the unitarity triangle angle phi2(alpha)
using B -> pi pi, B -> rho rho, and B -> rho pi decays. The measurements are
based on data samples collected with the Belle and BaBar detectors at the KEKB
and PEP-II e+e- colliders, respectively. We also report on a new measurement of
a CP-violating asymmetry in B -> a_1+ pi- decay which will allow to constrain
further the angle phi2.


title:
Supplementary Information for ``Rapid planetesimal formation in
  turbulent circumstellar discs''

abstract:
  This document contains refereed supplementary information for the paper
``Rapid planetesimal formation in turbulent circumstellar discs''. It contains
15 sections (\S1.1 -- \S1.15) that address a number of subjects related to the
main paper. We describe in detail the Poisson solver used to find the
self-potential of the solid particles, including a linear and a non-linear test
problem (\S1.3). Dissipative collisions remove energy from the motion of the
particles by collisional cooling (\S1.4), an effect that allows gravitational
collapse to occur in somewhat less massive discs (\S1.7). A resolution study of
the gravitational collapse of the boulders is presented in \S1.6. We find that
gravitational collapse can occur in progressively less massive discs as the
grid resolution is increased, likely due to the decreased smoothing of the
particle-mesh self-gravity solver with increasing resolution. In \S1.10 we show
that it is in good agreement with the Goldreich & Ward (1973) stability
analysis to form several-hundred-km-sized bodies, when the analysis is applied
to 5 AU and to regions of increased boulder column density. \S11 is devoted to
the measurement of random speeds and collision speeds between boulders. We find
good agreement between our measurements and analytical theory for the random
speeds, but the measured collision speeds are 3 times lower than expected from
analytical theory. Higher resolution studies, and an improved analytical theory
of collision speeds that takes into account epicyclic motion, will be needed to
determine whether collision speeds have converged. In \S1.12 we present models
with no magnetic fields. The boulder layer still exhibits strong clumping, due
to the streaming instability, if the global solids-to-gas ratio is increased by
a factor 3. Gravitational collapse occurs as readily as in magnetised discs.


title: Solute trapping and diffusionless solidification in a binary system

abstract:
  Numerous experimental data on the rapid solidification of binary systems
exhibit the formation of metastable solid phases with the initial (nominal)
chemical composition. This fact is explained by complete solute trapping
leading to diffusionless (chemically partitionless) solidification at a finite
growth velocity of crystals. Special attention is paid to developing a model of
rapid solidification which describes a transition from chemically partitioned
to diffusionless growth of crystals. Analytical treatments lead to the
condition for complete solute trapping which directly follows from the analysis
of the solute diffusion around the solid-liquid interface and atomic attachment
and detachment at the interface. The resulting equations for the flux balance
at the interface take into account two kinetic parameters: diffusion speed
$V_{DI}$ on the interface and diffusion speed $V_D$ in bulk phases. The model
describes experimental data on nonequilibrium solute partitioning in
solidification of Si-As alloys [M.J. Aziz et al., J. Cryst. Growth {\bf 148},
172 (1995); Acta Mater. {\bf 48}, 4797 (2000)] for the whole range of
solidification velocity investigated.


title:
Applications of a finite-dimensional duality principle to some
  prediction problems

abstract:
  Some of the most important results in prediction theory and time series
analysis when finitely many values are removed from or added to its infinite
past have been obtained using difficult and diverse techniques ranging from
duality in Hilbert spaces of analytic functions (Nakazi, 1984) to linear
regression in statistics (Box and Tiao, 1975). We unify these results via a
finite-dimensional duality lemma and elementary ideas from the linear algebra.
The approach reveals the inherent finite-dimensional character of many
difficult prediction problems, the role of duality and biorthogonality for a
finite set of random variables. The lemma is particularly useful when the
number of missing values is small, like one or two, as in the case of
Kolmogorov and Nakazi prediction problems. The stationarity of the underlying
process is not a requirement. It opens up the possibility of extending such
results to nonstationary processes.


title: The Isoconditioning Loci of Planar Three-DOF Parallel Manipulators

abstract:
  The subject of this paper is a special class of three-degree-of-freedom
parallel manipulators. The singular configurations of the two Jacobian matrices
are first studied. The isotropic configurations are then found based on the
characteristic length of this manipulator. The isoconditioning loci for the
Jacobian matrices are plotted to define a global performance index allowing the
comparison of the different working modes. The index thus resulting is compared
with the Cartesian workspace surface and the average of the condition number.


title:
Nearly Optimal Patchy Feedbacks for Minimization Problems with Free
  Terminal Time

abstract:
  The paper is concerned with a general optimization problem for a nonlinear
control system, in the presence of a running cost and a terminal cost, with
free terminal time. We prove the existence of a patchy feedback whose
trajectories are all nearly optimal solutions, with pre-assigned accuracy.


title: Geometric pi Josephson junction in d-wave superconducting thin films

abstract:
  A novel way to realize a pi Josephson junction is proposed, based on a weak
link in an unconventional d-wave superconductor with appropriately chosen
boundary geometry. The critical current of such a junction is calculated from a
fully selfconsistent solution of microscopic Eilenberger theory of
superconductivity. The results clearly show, that a transition to a pi
Josephson junction occurs for both low temperatures and small sizes of the
geometry.


title: Negative Komar Masses in Regular Stationary Spacetimes

abstract:
  A highly accurate multi-domain spectral method is used to study axially
symmetric and stationary spacetimes containing a black hole or disc of dust
surrounded by a ring of matter. It is shown that the matter ring can affect the
properties of the central object drastically. In particular, by virtue of the
ring's frame dragging, the so-called Komar mass of the black hole or disc can
become negative. A continuous transition from such discs to such black holes
can be found.


title:
Inference from correlated patterns: a unified theory for perceptron
  learning and linear vector channels

abstract:
  A framework to analyze inference performance in densely connected
single-layer feed-forward networks is developed for situations where a given
data set is composed of correlated patterns. The framework is based on the
assumption that the left and right singular value bases of the given pattern
matrix are generated independently and uniformly from Haar measures. This
assumption makes it possible to characterize the objective system by a single
function of two variables which is determined by the eigenvalue spectrum of the
cross-correlation matrix of the pattern matrix. Links to existing methods for
analysis of perceptron learning and Gaussian linear vector channels and an
application to a simple but nontrivial problem are also shown.


title: Coarse categories I: foundations

abstract:
  Following Roe and others (see, e.g., [MR1451755]), we (re)develop coarse
geometry from the foundations, taking a categorical point of view. In this
paper, we concentrate on the discrete case in which topology plays no role. Our
theory is particularly suited to the development of the_Roe (C*-)algebras_
C*(X) and their K-theory on the analytic side; we also hope that it will be of
use in the strictly geometric/algebraic setting of controlled topology and
algebra. We leave these topics to future papers.
  Crucial to our approach are nonunital coarse spaces, and what we call
_locally proper_ maps (which are actually implicit in [MR1988817]). Our_coarse
category_ Crs generalizes the usual one: its objects are nonunital coarse
spaces and its morphisms (locally proper) coarse maps modulo_closeness_. Crs is
much richer than the usual unital coarse category. As such, it has all nonzero
limits and all colimits. We examine various other categorical issues. E.g., Crs
does not have a terminal object, so we substitute a_termination functor_ which
will be important in the development of exponential objects (i.e., "function
spaces") and also leads to a notion of_quotient coarse spaces_. To connect our
methods with the standard methods, we also examine the relationship between Crs
and the usual coarse category of Roe.
  Finally we briefly discuss some basic examples and applications. Topics
include_metric coarse spaces_,_continuous control_ [MR1277522], metric and
continuously controlled_coarse simplices_,_sigma-coarse spaces_ [MR2225040],
and the relation between quotient coarse spaces and the K-theory of Roe
algebras (of particular interest for continuously controlled coarse spaces).


title:
B2 1144+35B, a giant low power radio galaxy with superluminal motion.
  Orientation and evidence for recurrent activity

abstract:
  The goal of this work is a detailed study of the nearby, low power radio
galaxy B2 1144+35B. For this purpose, we performed new Very Long Baseline Array
(VLBA) and Very Large Array (VLA) observations. This source has several
properties (bright, nearby, large range of spatial structures, visible
counterjet, etc.) that make it an excellent astrophysical laboratory for the
study of the evolution of radio jets. Here we report the detection of motion in
the counterjet at 0.23 $\pm$ 0.07 c, which allows us to estimate the
orientation of the parsec-scale jet at 33$^\circ \pm 7^\circ$ from the line of
sight, with an intrinsic velocity of (0.94$^{+0.06}_{-0.11}$)c. We also report
on a brightening of the core at high frequencies which we suggest could be the
result of a new component emerging from the core. High dynamic range VLBA
observations at 5 GHz reveal, for the first time, extended emission connecting
the core with the bright complex of emission that dominates the flux density of
the parsec scale structure at frequencies below 20 GHz. The evolution of this
bright complex is considered and its slow decline in flux density is
interpreted as the result of an interaction with the interstellar medium of the
host galaxy.


title: Packing defects and the width of biopolymer bundles

abstract:
  The formation of bundles composed of actin filaments and cross-linking
proteins is an essential process in the maintenance of the cells' cytoskeleton.
It has also been recreated by in-vitro experiments, where actin networks are
routinely produced to mimic and study the cellular structures. It has long been
observed that these bundles seem to have a well defined width distribution,
which has not been adequately described theoretically. We propose here that
packing defects of the filaments, quenched and random, contribute an effective
repulsion that counters the cross-linking adhesion energy and leads to a well
defined bundle width. This is a two-dimensional strain-field version of the
classic Rayleigh instability of charged droplets.


title:
Exact wave functions of electron in a quantum dot with account of the
  Rashba spin-orbit interaction

abstract:
  We present the exact wave functions and energy levels of electron in a
two-dimensional circular quantum dot in the presence of the Rashba spin-orbit
interaction. The confinement is described by the realistic potential well of
finite depth.


title: Top Quark Spin Polarization in e \gamma Collision

abstract:
  We investigate the degree of spin polarization of single top quarks in the
$e\gamma$ collision via the process $e^{+} \gamma \to t \bar{b} \bar{\nu_{e}}$
with center of mass energies $\sqrt{s}$=0.5, 1 and 1.5 TeV of the parental
linear $e^{+}e^{-}$ collider. Dominant spin fractions and spin asymmetries for
the various top quark spin bases are investigated. We show that $e^{+}$-beam
direction is the favorite top quark spin decomposition axis. It is found to be
comparable with the ones in $pp$ and $ep$ collisions.


title: Magnesium Isotopes in Halo Stars

abstract:
  We have determined Mg isotope ratios in halo field dwarfs and giants in the
globular cluster M71 based on high S/N high spectral resolution (R = 10$^5$)
Keck HIRES spectra. Unlike previous claims of an important contribution from
intermediate-mass AGB stars to the Galactic halo, we find that our
$^{26}$Mg/$^{24}$Mg ratios can be explained by massive stars.


title: Modules with reducible complexity

abstract:
  For a commutative Noetherian local ring we define and study the class of
modules having reducible complexity, a class containing all modules of finite
complete intersection dimension. Various properties of this class of modules
are given, together with results on the vanishing of homology and cohomology.


title: Is critical 2D percolation universal?

abstract:
  The aim of this paper is to explore possible ways of extending Smirnov's
proof of Cardy's formula for critical site-percolation on the triangular
lattice to other cases (such as bond-percolation on the square lattice); the
main question we address is that of the choice of the lattice embedding into
the plane which gives rise to conformal invariance in the scaling limit. Even
though we were not able to produce a complete proof, we believe that the ideas
presented here go in the right direction.


title: No-Signalling Bound on Quantum State Discrimination

abstract:
  Quantum correlations do not allow signalling, and any operation which may be
performed on one system of an entangled pair cannot be detected by measurement
of the other system alone. This no-signalling condition limits allowed
operations and, in the context of quantum communication, may be used to put
bounds on quantum state discrimination. We find that the natural figure of
merit to consider is the confidence in identifying a state, which is optimised
by the maximum confidence strategy. We show that this strategy may be derived
from the no-signalling condition, and demonstrate the relationship between
maximum confidence measurements and entanglement concentration.


title:
Monitoring the rotary motors of single FoF1-ATP synthase by synchronized
  multi channel TCSPC

abstract:
  Confocal time resolved single-molecule spectroscopy using pulsed laser
excitation and synchronized multi channel time correlated single photon
counting (TCSPC) provides detailed information about the conformational changes
of a biological motor in real time. We studied the formation of adenosine
triphosphate, ATP, from ADP and phosphate by FoF1-ATP synthase. The reaction is
performed by a stepwise internal rotation of subunits of the lipid
membrane-embedded enzyme. Using fluorescence resonance energy transfer, FRET,
we detected rotation of this biological motor by sequential changes of
intramolecular distances within a single FoF1-ATP synthase. Prolonged
observation times of single enzymes were achieved by functional immobilization
to the glass surface. The stepwise rotary subunit movements were identified by
Hidden Markov Models (HMM) which were trained with single-molecule FRET
trajectories. To improve the accuracy of the HMM analysis we included the
single-molecule fluorescence lifetime of the FRET donor and used alternating
laser excitation to co-localize the FRET acceptor independently within a photon
burst. The HMM analysis yielded the orientations and dwell times of rotary
subunits during stepwise rotation. In addition, the action mode of bactericidal
drugs, i.e. inhibitors of FoF1-ATP synthase like aurovertin, could be
investigated by the time resolved single-molecule FRET approach.


title: The jet of Markarian 501 from the sub-parsec to the kpc scale

abstract:
  We have observed the BL Lac object Markarian 501 at 1.4 GHz with the High
Sensitivity Array and at 86 GHz with the global VLBI mm array. Thanks to the
great resolution and sensitivity provided by these instruments, we probe
regions of the radio jets never accessed before. The new data at 1.4 GHz allow
us to map the one-sided jet at large distances from the core, and to constrain
jet properties thanks to the high jet to counter-jet brightness ratio. The 86
GHz data give us a high resolution image of the nuclear region. Putting
together these new results and available published data we discuss the
properties of this source from sub-parsec to kiloparsec scales.


title: On the Hochschild (co)homology of quantum exterior algebras

abstract:
  We compute the Hochschild cohomology and homology of a class of quantum
exterior algebras, with coefficients in twisted bimodules. As a result we
obtain several interesting examples of the homological behavior of these
algebras.


title: New Origin of a Bilinear Mass Matrix Form

abstract:
  The charged lepton mass formula can be explained when the masses are
propotinal to the squared vacuum expectation values (VEVs) of scalar fields. We
introduce U(3) flavor symmetry and its nonet scalar field $\Phi$, whose VEV
structure plays an essential role for generating the fermion mass spectrum. We
can naturally obtain bilinear form of the Yukawa coupling
  $Y_{ij} \propto \sum_k <\Phi_{ik}> <\Phi_{kj}>$ without the
non-renormalizable interactions, when the flavor symmetry is broken only
through the Yukawa coupling and tadpole terms. We also speculate the possible
VEV structure of $<\Phi>$.


title: On support varieties for modules over complete intersections

abstract:
  We show that, over a local complete intersection, every possible variety is
realized as the cohomological support variety of some module. Moreover, we show
that the projective variety of a complete indecomposable maximal Cohen-Macaulay
module is connected.


title:
How Compact are the Cores of AGN? Sub-Parsec Scale Imaging with VLBI at
  Millimeter Wavelengths

abstract:
  We study the most central regions of AGN jets with an angular resolution of
tens of micro-arcseconds using VLBI at millimeter wavelengths (mm-VLBI). We
present and discuss a new 86 GHz VLBI survey of compact radio sources. We show
new high dynamic range images of two nearby radio galaxies (3C 120 and M87). In
M87 the size of the compact VLBI core (the jet base) is < 15 Schwarzschild
radii. Future mm-VLBI observations at 1 mm and shorter wavelengths should lead
to images of galactic and extragalactic radio sources with a spatial resolution
down to a few Schwarzschild radii of the central super massive black holes. To
achieve this, the participation of large and sensitive millimeter and
sub-millimeter telescopes in VLBI is essential. Owing to their high sensitivity
existing and planned phased interferometers like the IRAM Plateau de Bure
interferometer, CARMA, the SMA and ALMA could play an important role.


title: Pattern collapse as a mechanism for the formation of solitary structures

abstract:
  We report a new mechanism for the formation of localized states, which takes
place without front propagation. Correspondingly, localized structures appear
as solitary states, displaying a behavior of single independent cells. The
phenomenon is observed in the liquid crystal light-valve experiment and is
described by a one-dimensional normal form model. We show that such solitary
structures exist when a pattern solution collapses and its ghost remains to
influence the phase portrait.


title: Twisted support varieties

abstract:
  We define and study twisted support varieties for modules over an Artin
algebra, where the twist is induced by an automorphism of the algebra. Under a
certain finite generation hypothesis, we show that the twisted variety of a
module satisfies Dade's Lemma and is one dimensional precisely when the module
is periodic with respect to the twisting automorphism. As a special case we
obtain results on DTr-periodic modules over Frobenius algebras.


title: Circular dielectric cavity and its deformations

abstract:
  The construction of perturbation series for slightly deformed dielectric
circular cavity is discussed in details. The obtained formulae are checked on
the example of cut disks. A good agreement is found with direct numerical
simulations and far-field experiments.


title: The 1:+2 / 1:-2 resonance

abstract:
  On the linear level elliptic equilibria of Hamiltonian systems are mere
superpositions of harmonic oscillators. Non-linear terms can produce
instability, if the ratio of frequencies is rational and the Hamiltonian is
indefinite. In this paper we study the frequency ratio 1/2 and its unfolding.
In particular we show that for the indefinite case (1:-2) the frequency ratio
map in a neighbourhood of the origin has a critical point, i.e. the twist
condition is violated for one torus on every energy surface near the energy of
the equilibrium. In contrast, we show that the frequency map itself is
non-degenerate (i.e. the Kolmogorov non-degeneracy condition holds) for every
torus in a neighbourhood of the equilibrium point. As a byproduct we are able
to obtain another proof of fractional monodromy in the 1:-2 resonance.


title: Kinematic analysis of the 3-RPR parallel manipulator

abstract:
  The aim of this paper is the kinematic study of a 3-RPR planar parallel
manipulator where the three fixed revolute joints are actuated. The direct and
inverse kinematic problem as well as the singular configuration is
characterized. On parallel singular configurations, the motion produce by the
mobile platform can be compared to the Reuleaux straight-line mechanism.


title:
Relation of Curie temperature and conductivity: (Ga,Mn)As alloy as a
  case study

abstract:
  Experimental investigations of diluted magnetic semiconductors indicate a
strong relation between Curie temperature and conductivity. Both quantities
depend non trivially on the concentration of magnetic impurities, the carrier
density, and the presence of compensating defects. We calculate both Curie
temperature and conductivity of (Ga,Mn)As alloys in a selfconsistent manner
based on the same first principles Hamiltonian in which the presence of
compensating defects is taken into account. The effect of As-antisites and
Mn-interstitials is determined separately and a good agreement between theory
and experiment exists only in the case where the dominating mechanism of is due
to the Mn-interstitials.


title: Primordial Light Element Abundances

abstract:
  After few minutes the Universe evolved through conditions of temperature and
density which permitted the first synthesis of astrophysically interesting
abundances of D, 3He, 4He and 7Li. The relic abundances are sensitive probes of
the nucleon density and so are the CMB acoustic oscillations, somewhat 400000
years later, which allow a stringent cross check. The CMB high precision
estimate of the baryon density by WMAP is currently used as input parameter for
standard big bang nucleosynthesis (SBBN) to interpret primordial bundances
rather then being directly derived from the observations of light elements as
was common use before. New atomic physics and identification of systematics
lead to an upwards revision of the 4He primordial abundance at Yp=0.2477 +/-
0.0029 (Peimbert et al 2007) removing a major source of tension between SBBN
and WMAP. The D/H as measured in QSO high redshift absorbing clouds shows an
excess of scatter but the mean value is found in spectacular agreement with the
WMAP prediction. The Li/H recently redetermined in halo dwarfs is more than a
factor 4 lower than expected. We argue that the difference reduces to a factor
2 when the IRFM Teff scale is adopted. Diffusion has been suggested to have
depleted Li in halo dwarfs by the required amount to remove the gap, however
this would imply an implausible high abundance of the more fragile 6Li detected
in some halo dwarfs, thus leaving the puzzle open.


title:
Reversible skew Laurent polynomial rings and deformations of Poisson
  automorphisms

abstract:
  A skew Laurent polynomial ring R[x^{\pm 1};\alpha] is reversible if it has a
reversing automorphism, that is, an automorphism of period two that transposes
x and x^{-1} and restricts to an automorphism of R. We study invariants for
reversing automorphisms and apply our methods to determine the rings of
invariants of reversing automorphisms of two simple skew Laurent polynomial
rings, namely a localization of the enveloping algebra of the two-dimensional
non-abelian solvable Lie algebra and the coordinate ring of the quantum torus.
These two skew Laurent polynomial rings are deformations of Poisson algebras
and we interpret their reversing automorphisms and their invariants as
deformations of Poisson automorphisms and their invariants.


title: Best constants for Lipschitz embeddings of metric spaces into c_0

abstract:
  We answer a question of Aharoni by showing that every separable metric space
can be Lipschitz 2-embedded into $c_0$ and this result is sharp; this improves
earlier estimates of Aharoni, Assouad and Pelant. We use our methods to examine
the best constant for Lipschitz embeddings of the classical $\ell_p-$spaces
into $c_0$ and give other applications. We prove that if a Banach space embeds
almost isometrically into $c_0$, then it embeds linearly almost isometrically
into $c_0$. We also study Lipschitz embeddings into $c_0^+$.


title: Method of self-similar factor approximants

abstract:
  The method of self-similar factor approximants is completed by defining the
approximants of odd orders, constructed from the power series with the largest
term of an odd power. It is shown that the method provides good approximations
for transcendental functions. In some cases, just a few terms in a power series
make it possible to reconstruct a transcendental function exactly. Numerical
convergence of the factor approximants is checked for several examples. A
special attention is paid to the possibility of extrapolating the behavior of
functions, with arguments tending to infinity, from the related asymptotic
series at small arguments. Applications of the method are thoroughly
illustrated by the examples of several functions, nonlinear differential
equations, and anharmonic models.


title: Can we trust semiclassical description of particle creation?

abstract:
  The predictions of the semiclassical description of particle creation based
on QFT in classical backgrounds may be significantly modified when the source
of the classical background is also quantized and backreaction is taken into
account. In the cases of a stable charged particle, expanding empty (Milne)
universe, and de Sitter universe with a true cosmological constant, the
semiclassical particle creation is completely blocked up.


title:
Asymptotics of LRS Bianchi type I cosmological models with elastic
  matter

abstract:
  In this paper we report on results in the study of spatially homogeneous
cosmological models with elastic matter. We show that the behavior of elastic
solutions is fundamentally different from that of perfect fluid solutions
already in the case of locally rotationally symmetric (LRS) Bianchi type I
models; this is true even when the elastic material resembles a perfect fluid
very closely. In particular, the approach to the initial singularity is
characterized by an intricate oscillatory behavior of the scale factors, while
the future asymptotic behavior is described by isotropization rates that differ
significantly from those of perfect fluids.


title: Finite-dimensional simple Poisson modules

abstract:
  We prove a result that can be applied to determine the finite-dimensional
simple Poisson modules over a Poisson algebra and apply it to numerous
examples. In the discussion of the examples, the emphasis is on the
correspondence with the finite-dimensional simple modules over deformations and
on the behaviour of finite-dimensional simple Poisson modules on the passage
from a Poisson algebra to the Poisson subalgebra of invariants for the action
of a finite group of Poisson automorphisms.


title:
The solution of the Minkowski problem for open surfaces in Riemannian
  space

abstract:
  Author reduces the Minkowski problem to the problem of construction the
G-deformations preserving the product of principal curvatures for every point
of surface in Riemannian space. G-deformation transfers every normal vector of
surface in parallel along the path of the translation for each point of
surface. The continuous G-deformations preserving the product of principal
curvatures of surface with boundary are considered in this article. The
equations of deformations which are obtained in this paper reduce to the
nonlinear boundary-value problem. The method of construction continuous
G-deformations preserving the product of principal curvatures of surface with
boundary and its qualitative analysis are presented in this article


title:
Experimental measurement of acceleration correlations and pressure
  structure functions in high Reynolds number turbulence

abstract:
  We present measurements of fluid particle accelerations in turbulent water
flows between counter-rotating disks using three-dimensional Lagrangian
particle tracking. By simultaneously following multiple particles with
sub-Kolmogorov-time-scale temporal resolution, we measured the spatial
correlation of fluid particle acceleration at Taylor microscale Reynolds
numbers between 200 and 690. We also obtained indirect, non-intrusive
measurements of the Eulerian pressure structure functions by integrating the
acceleration correlations. Our experimental data provide strong support to the
theoretical predictions of the acceleration correlations and the pressure
structure function in isotropic high Reynolds number turbulence by Obukhov and
Yaglom in 1951. The measured pressure structure functions display K41 scaling
in the inertial range.


title: The effect of time-dependent coupling on non-equilibrium steady states

abstract:
  Consider (for simplicity) two one-dimensional semi-infinite leads coupled to
a quantum well via time dependent point interactions. In the remote past the
system is decoupled, and each of its components is at thermal equilibrium. In
the remote future the system is fully coupled. We define and compute the non
equilibrium steady state (NESS) generated by this evolution. We show that when
restricted to the subspace of absolute continuity of the fully coupled system,
the state does not depend at all on the switching. Moreover, we show that the
stationary charge current has the same invariant property, and derive the
Landau-Lifschitz and Landauer-Buttiker formulas.


title:
Generalized Gamma Convolutions, Dirichlet means, Thorin measures, with
  explicit examples

abstract:
  In Section 1, we present a number of classical results concerning the
Generalized Gamma Convolution (:GGC) variables, their Wiener-Gamma
representations, and relation with the Dirichlet processes.To a GGC variable,
one may associate a unique Thorin measure. Let $G$ a positive r.v. and
$\Gamma_t(G)$ (resp. $\Gamma_t(1/G))$ the Generalized Gamma Convolution with
Thorin measure $t$-times the law of $G$ (resp. the law of $1/G$). In Section 2,
we compare the laws of $\Gamma_t(G)$ and $\Gamma_t(1/G)$.In Section 3, we
present some old and some new examples of GGC variables, among which the
lengths of excursions of Bessel processes straddling an independent exponential
time.


title:
Cusp anomalous dimension in maximally supersymmetric Yang-Mills theory
  at strong coupling

abstract:
  We construct an exact analytical solution to the integral equation which is
believed to describe logarithmic growth of the anomalous dimensions of high
spin operators in planar N=4 super Yang-Mills theory and use it to determine
the strong coupling expansion of the cusp anomalous dimension.


title: Sharp Spectral Asymptotics for Dirac Energy

abstract:
  I derive sharp semiclassical asymptotics of $\int |e_h(x,y,0)|^2\omega(x,y)
dx dy$ where $e_h(x,y,\tau)$ is the Schwartz kernel of the spectral projector
and $\omega(x,y)$ is singular as $x=y$. I also consider asymptotics of more
general expressions.


title: Electron heating in metallic resistors at sub-Kelvin temperature

abstract:
  In the presence of Joule heating, the electronic temperature in a metallic
resistor placed at sub-Kelvin temperatures can significantly exceed the phonon
temperature. Electron cooling proceeds mainly through two processes: electronic
diffusion to and from the connecting wires and electron-phonon coupling. The
goal of this paper is to present a general solution of the problem, in a form
that can easily be used in practical situations. As an application, we compute
two quantities that depend on the electronic temperature profile: the second
and the third cumulant of the current noise at zero frequency, as a function of
the voltage across the resistor. We also consider time dependent heating, an
issue relevant for experiments in which current pulses are used, for instance
in time-resolved calorimetry experiments.


title: Working and Assembly Modes of the Agile Eye

abstract:
  This paper deals with the in-depth kinematic analysis of a special spherical
parallel wrist, called the Agile Eye. The Agile Eye is a three-legged spherical
parallel robot with revolute joints in which all pairs of adjacent joint axes
are orthogonal. Its most peculiar feature, demonstrated in this paper for the
first time, is that its (orientation) workspace is unlimited and flawed only by
six singularity curves (rather than surfaces). Furthermore, these curves
correspond to self-motions of the mobile platform. This paper also demonstrates
that, unlike for any other such complex spatial robots, the four solutions to
the direct kinematics of the Agile Eye (assembly modes) have a simple geometric
relationship with the eight solutions to the inverse kinematics (working
modes).


title: A convenient category for directed homotopy

abstract:
  We propose a convenient category for directed homotopy consisting of
preordered topological spaces generated by cubes. Its main advantage is that,
like the category of topological spaces generated by simplices suggested by J.
H. Smith, it is locally presentable.


title: On the proximinality of ridge functions

abstract:
  Using two results of Garkavi, Medvedev and Khavinson, we give sufficient
conditions for proximinality of sums of two ridge functions with bounded and
continuous summands in the spaces of bounded and continuous multivariate
functions respectively. In the first case, we give an example which shows that
the corresponding sufficient condition cannot be made weaker for some subsets
of $\mathbb{R}^{n}$. In the second case, we obtain also a necessary condition
for proximinality. All the results are furnished with plenty of examples. The
results, examples and following discussions naturally lead us to a conjecture
on the proximinality of the considered class of ridge functions. The main
purpose of the paper is to draw readers' attention to this conjecture.


title: Epidemics on random graphs with tunable clustering

abstract:
  In this paper, a branching process approximation for the spread of a
Reed-Frost epidemic on a network with tunable clustering is derived. The
approximation gives rise to expressions for the epidemic threshold and the
probability of a large outbreak in the epidemic. It is investigated how these
quantities varies with the clustering in the graph and it turns out for
instance that, as the clustering increases, the epidemic threshold decreases.
The network is modelled by a random intersection graph, in which individuals
are independently members of a number of groups and two individuals are linked
to each other if and only if they share at least one group.


title: The beginning of string theory: a historical sketch

abstract:
  In this note we follow the historical development of the ideas that led to
the formulation of String Theory. We start from the inspired guess of Veneziano
and its extension to the scattering of $N$ scalar particles, then we describe
how the study of its factorization properties allowed to identify the physical
spectrum making the string worldsheet manifest and finally we discuss how the
critical values of the intercept of the Regge trajectory and of the critical
dimension were fixed to 1 and 26.


title:
Reconstruction of nuclear charged fragment trajectories from a large gap
  sweeper magnet

abstract:
  A new method to reconstruct charged fragment four-momentum vectors from
measured trajectories behind an open, large gap, magnetic dispersion element (a
sweeper magnet) has been developed. In addition to the position and angle
behind the magnet it includes the position measurement in the dispersive
direction at the target. The method improves the energy and angle resolution of
the reconstruction significantly for experiments with fast rare isotopes, where
the beam size at the target position is large.


title:
On the modularity of supersingular elliptic curves over certain totally
  real number fields

abstract:
  We study generalisations to totally real fields of methods originating with
Wiles and Taylor-Wiles. In view of the results of Skinner-Wiles on elliptic
curves with ordinary reduction, we focus here on the case of supersingular
reduction. Combining these, we then obtain some partial results on the
modularity problem for semistable elliptic curves, and end by giving some
applications of our results, for example proving the modularity of all
semistable elliptic curves over $\mathbb{Q}(\sqrt{2})$.


title:
Scaled frequency-dependent transport in the mesoscopically
  phase-separated colossal magnetoresistive manganite
  La_{0.625-y}Pr_yCa_{0.375}MnO_3

abstract:
  We address the issue of massive phase separation (PS) in manganite family of
doped Mott insulators through ac conductivity measurements on
La$_{0.625-y}$Pr$_{y}$Ca$_{0.375}$MnO$_{3}$ (0.375 $\leq$ y $\leq$ 0.275), and
establish applicability of the scaling theory of percolation in the critical
regime of the PS. Measurements of dc resistivity, magnetization (M(T)) and
electron diffraction show incomplete growth of a ferromagnetic (FM) metallic
component on cooling the high temperature charge ordered (CO) phase well below
Curie temperature. The impedance $\mid$Z(T,f)$\mid$ measured over a frequency
(f) range of 10 Hz to 10 MHz in the critical regime follows a universal scaling
of the form $\approx$ R(T,0)g(f$\xi^{2+\theta}$) with $\theta$ $\approx$ 0.86
and the normalized correlation length varying from 1 to 4, suggesting anomalous
diffusion of holes in percolating FM clusters.


title:
Single \pi^- production in np collisions for excess energies up to 90
  MeV

abstract:
  The quasifree reaction $np\to pp\pim$ was studied in a kinematically complete
experiment by bombarding a liquid hydrogen target with a deuteron beam of
momentum 1.85 GeV/c and analyzing the data along the lines of the spectator
model. In addition to the three charged ejectiles the spectator proton was also
detected in the large-acceptance time-of-flight spectrometer COSY-TOF. It was
identified by its momentum and flight direction thus yielding access to the
Fermi motion of the bound neutron and to the effective neutron 4-momentum
vector $\mathbb{P}_n$ which differed from event to event. A range of almost 90
MeV excess energy above threshold was covered. Energy dependent angular
distributions, invariant mass spectra as well as fully covered Dalitz plots
were deduced. Sizeable $pp$ FSI effects were found as were contributions of $p$
and $d$ partial waves. The behavior of the elementary cross section
$\sigma_{01}$ close to threshold is discussed in view of new cross section
data. In comparison with existing literature data the results provide a
sensitive test of the spectator model.


title: Modification of the turbulent energy cascade by polymer additives

abstract:
  By tracking small particles in the bulk of an intensely turbulent flow, we
show that even a very small concentration of long-chain polymers disrupts the
usual turbulent energy cascade. The polymers affect scales much larger than
their physical size, from the dissipation range to the inertial range. The
effect depends strongly on the polymer concentration. While the
dissipative-scale statistics change continuously as the polymer concentration
is increased, the inertial-range energy transfer rate is only altered by the
polymer additives when the concentration is above a threshold (approximately 5
parts per million by weight for the polymer we used).


title: Integrable Hierarchies and Information Measures

abstract:
  In this paper we investigate integrable models from the perspective of
information theory, exhibiting various connections. We begin by showing that
compressible hydrodynamics for a one-dimesional isentropic fluid, with an
appropriately motivated information theoretic extension, is described by a
general nonlinear Schrodinger (NLS) equation. Depending on the choice of the
enthalpy function, one obtains the cubic NLS or other modified NLS equations
that have applications in various fields. Next, by considering the integrable
hierarchy associated with the NLS model, we propose higher order information
measures which include the Fisher measure as their first member. The lowest
members of the hiearchy are shown to be included in the expansion of a
regularized Kullback-Leibler measure while, on the other hand, a suitable
combination of the NLS hierarchy leads to a Wootters type measure related to a
NLS equation with a relativistic dispersion relation. Finally, through our
approach, we are led to construct an integrable semi-relativistic NLS equation.


title: Optimality and uniqueness of the (4,10,1/6) spherical code

abstract:
  Linear programming bounds provide an elegant method to prove optimality and
uniqueness of an (n,N,t) spherical code. However, this method does not apply to
the parameters (4,10,1/6). We use semidefinite programming bounds instead to
show that the Petersen code, which consists of the midpoints of the edges of
the regular simplex in dimension 4, is the unique (4,10,1/6) spherical code.


title: The conjunction fallacy and interference effects

abstract:
  In the present article we consider the conjunction fallacy, a well known
cognitive heuristic experimentally tested in cognitive science, which occurs
for intuitive judgments in situations of bounded rationality. We show that the
quantum formalism can be used to describe in a very simple way this fallacy in
terms of interference effect. We evidence that the quantum formalism leads
quite naturally to violations of Bayes' rule when considering the estimated
probability of the conjunction of two events. By defining the concept of
maximal conjunction error, we find a good agreement with experimental results.
Thus we suggest that in cognitive science the formalism of quantum mechanics
can be used to describe a \textit{quantum regime}, the bounded-rationality
regime, where the cognitive heuristics are valid.


title: Categorification of Wedderburn's basis for \mathbb{C}[S_n]

abstract:
  M. Neunh{\"o}ffer studies in \cite{Ne} a certain basis of $\mathbb{C}[S_n]$
with the origins in \cite{Lu} and shows that this basis is in fact Wedderburn's
basis. In particular, in this basis the right regular representation of $S_n$
decomposes into a direct sum of irreducible representations (i.e. Specht or
cell modules). In the present paper we rediscover essentially the same basis
with a categorical origin coming from projective-injective modules in certain
subcategories of the BGG-category $\mathcal{O}$. An important role in our
arguments is played by the dominant projective module in each of these
categories. As a biproduct of the study of this dominant projective module we
show that {\it Kostant's problem} (\cite{Jo}) has a negative answer for some
simple highest weight module over the Lie algebra $\mathfrak{sl}_4$, which
disproves the general belief that Kostant's problem should have a positive
answer for all simple highest weight modules in type $A$.


title: Noncommutative Minisuperspace Cosmology

abstract:
  We consider the noncommutative minisuperspace classical and quantum
cosmologies.


title: Gauge Model in D=3, N=5 Harmonic Superspace

abstract:
  We construct the Grassmann-analytic gauge superfields in D=3, N=5 harmonic
superspace using the SO(5)/U(1)xU(1) harmonics. These gauge N=5 superfields
contain an infinite number of bosonic and fermionic fields arising from
decompositions in harmonics and Grassmann coordinates. The bosonic sector of
this supermultiplet includes the gauge field A_m, the additional nongauge
vector field B_m, the scalar field S, two SO(5)-vector scalar fields and an
infinite number of auxiliary fields with SO(5) indices. The nonabelian
Chern-Simons-type action in the N=5 analytic harmonic superspace is
constructed. This action is also invariant with respect to the sixth
supersymmetry realized on the N=5 gauge superfields. The component Lagrangian
describes the scale-invariant nontrivial interactions of the gauge Chern-Simons
field A_m with B_m, S and other basic and auxiliary fields. All auxiliary
fields can be excluded from this Lagrangian.


title: Liftable D_4-Covers

abstract:
  Let k be an algebraically closed field of characteristic p and let G be a
subgroup of Aut(k[[t]]) be a faithful action on a local power series ring over
k. Let R be a discrete valuation ring of characteristic 0 with residue field k.
One asks, whether it is possible to find a faithful action G inside Aut(R[[t]])
which reduces to the given action, i.e. a lift to characteristic 0. We show
that liftable actions exists in the case that G = D_4 and p = 2. In fact we
introduce a family, the supersimple D_4 -actions, which can always be lifted to
characteristic 0.


title:
Taking the Measure of the Universe: Precision Astrometry with SIM
  PlanetQuest

abstract:
  Precision astrometry at microarcsecond accuracy has application to a wide
range of astrophysical problems. This paper is a study of the science questions
that can be addressed using an instrument that delivers parallaxes at about 4
microarcsec on targets as faint as V = 20, differential accuracy of 0.6
microarcsec on bright targets, and with flexible scheduling. The science topics
are drawn primarily from the Team Key Projects, selected in 2000, for the Space
Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities
of this mission to illustrate the importance of the next level of astrometric
precision in modern astrophysics. SIM PlanetQuest is currently in the detailed
design phase, having completed all of the enabling technologies needed for the
flight instrument in 2005. It will be the first space-based long baseline
Michelson interferometer designed for precision astrometry. SIM will contribute
strongly to many astronomical fields including stellar and galactic
astrophysics, planetary systems around nearby stars, and the study of quasar
and AGN nuclei. SIM will search for planets with masses as small as an Earth
orbiting in the `habitable zone' around the nearest stars using differential
astrometry, and could discover many dozen if Earth-like planets are common. It
will be the most capable instrument for detecting planets around young stars,
thereby providing insights into how planetary systems are born and how they
evolve with time. SIM will observe significant numbers of very high- and
low-mass stars, providing stellar masses to 1%, the accuracy needed to
challenge physical models. Using precision proper motion measurements, SIM will
probe the galactic mass distribution and the formation and evolution of the
Galactic halo. (abridged)


title: Non-commutative phase space and its space-time symmetry

abstract:
  First a description of 2+1 dimensional non-commutative(NC) phase space is
presented, where the deformation of the planck constant is given. We find that
in this new formulation, generalized Bopp's shift has a symmetric
representation and one can easily and straightforwardly define the star product
on NC phase space. Then we define non-commutative Lorentz transformations both
on NC space and NC phase space. We also discuss the Poincare symmetry. Finally
we point out that our NC phase space formulation and the NC Lorentz
transformations can be applicable to any even dimensional NC space and NC phase
space.


title: Evolution of geometric structures in intense turbulence

abstract:
  We report measurements of the evolution of lines, planes, and volumes in an
intensely turbulent laboratory flow using high-speed particle tracking. We find
that the classical characteristic time scale of an eddy at the initial scale of
the object considered is the natural time scale for the subsequent evolution.
The initial separation may only be neglected if this time scale is much smaller
than the largest turbulence time scale, implying extremely high turbulence
levels.


title:
The asymptotic behaviour of recurrence coefficients for orthogonal
  polynomials with varying exponential weights

abstract:
  We consider orthogonal polynomials $\{p_{n,N}(x)\}_{n=0}^{\infty}$ on the
real line with respect to a weight $w(x)=e^{-NV(x)}$ and in particular the
asymptotic behaviour of the coefficients $a_{n,N}$ and $b_{n,N}$ in the three
term recurrence $x \pi_{n,N}(x) = \pi_{n+1,N}(x) + b_{n,N} \pi_{n,N}(x) +
a_{n,N} \pi_{n-1,N}(x)$. For one-cut regular $V$ we show, using the Deift-Zhou
method of steepest descent for Riemann-Hilbert problems, that the diagonal
recurrence coefficients $a_{n,n}$ and $b_{n,n}$ have asymptotic expansions as
$n \to \infty$ in powers of $1/n^2$ and powers of $1/n$, respectively.


title: Hyperon decay form factors in chiral perturbation theory

abstract:
  We present a complete calculation of the SU(3)-breaking corrections to the
hyperon vector form factors up to O(p^4) in covariant baryon chiral
perturbation theory. Partial higher-order contributions are obtained, and we
discuss chiral extrapolations of the vector form factor at zero momentum
transfer. In addition we derive low-energy theorems for the subleading moments
in hyperon decays, the weak Dirac radii and the weak anomalous magnetic
moments, up to O(p^4).


title: Cruising through molecular bound state manifolds with radio frequency

abstract:
  The emerging field of ultracold molecules with their rich internal structure
is currently attracting a lot of interest. Various methods have been developed
to produce ultracold molecules in pre-set quantum states. For future
experiments it will be important to efficiently transfer these molecules from
their initial quantum state to other quantum states of interest. Optical Raman
schemes are excellent tools for transfer, but can be involved in terms of
equipment, laser stabilization and finding the right transitions. Here we
demonstrate a very general and simple way for transfer of molecules from one
quantum state to a neighboring quantum state with better than 99% efficiency.
The scheme is based on Zeeman tuning the molecular state to avoided level
crossings where radio-frequency transitions can then be carried out. By
repeating this process at different crossings, molecules can be successively
transported through a large manifold of quantum states. As an important
spin-off of our experiments, we demonstrate a high-precision spectroscopy
method for investigating level crossings.


title: Surface Plasmon Polariton Self-Focusing by Ponderomotive Forces

abstract:
  Nonlinear properties of Surface Plasmon Polaritons stemming from the inherent
electron plasma nonlinearity of the metal layers are investigated. A
fluid-mechanics plasma model is used to describe the electron motion in metals.
The nonlinear ponderomotive force repels the electrons from the high field
intensity region, effectively reducing the local plasma frequency and the
corresponding real part of the refractive index results in Kerr like
self-focusing. The field confinement to the low carrier density region also
assists also in reducing the propagation losses, which usually inhibit
practical nanoplasmonic circuits. Surface plasmon self focusing and nonlinear
spectrum modifications, predicted by our model, are demonstrated by preliminary
experiments.


title:
Quantum indirect estimation theory and joint estimate of all moments of
  two incompatible observables

abstract:
  We introduce the quantum indirect estimation theory, which provides a general
framework to address the problem of which ensemble averages can be estimated by
means of an available set of measuring apparatuses, e. g. estimate the ensemble
average of an observable by measuring other observable. A main ingredient in
this approach is that of informationally complete (infocomplete in short)
measurements, which allow to estimate the ensemble average of any arbitrary
system operator, as for quantum tomography. This naturally leads to the more
stringent concept of AB-informationally complete measurements, by which one can
estimate jointly all the moments of two incompatible observables A and B. After
analyzing all general properties of such measurements, we address the problem
of their optimality, and we completely solve the case of qubits, showing that a
sigma_x sigma_y-infocomplete measurement is less noisy than any infocomplete
one. We will also discuss the relation between the concept of
AB-infocompleteness and the notion of joint measurement of observables A and B.


title: Chess, Chance and Conspiracy

abstract:
  Chess and chance are seemingly strange bedfellows. Luck and/or randomness
have no apparent role in move selection when the game is played at the highest
levels. However, when competition is at the ultimate level, that of the World
Chess Championship (WCC), chess and conspiracy are not strange bedfellows,
there being a long and colorful history of accusations levied between
participants. One such accusation, frequently repeated, was that all the games
in the 1985 WCC (Karpov vs Kasparov) were fixed and prearranged move by move.
That this claim was advanced by a former World Champion, Bobby Fischer, argues
that it ought be investigated. That the only published, concrete basis for this
claim consists of an observed run of particular moves, allows this
investigation to be performed using probabilistic and statistical methods. In
particular, we employ imbedded finite Markov chains to evaluate run statistic
distributions. Further, we demonstrate how both chess computers and game data
bases can be brought to bear on the problem.


title: A course on Combinatorial Algorithms

abstract:
  The paper presents a course on Combinatorial Algorithms that is based on the
drafts of the author that he used while teaching the course in the Department
of Informatics and Applied Mathematics of Yerevan State University, Armenia
from February 2007 to June 2007.


title:
Localization of light in a lamellar structure with left-handed medium :
  the light wheel

abstract:
  The contra-directional coupling between a left-handed monomode waveguide and
a right-handed monomode waveguide is rigorously studied using a complex plane
analysis. Light is shown to rotate in this lamellar structure forming a very
exotic mode which we have called a light wheel. The light wheel can be excited
using evanescent coupling or by placing sources in one of the waveguides. This
structure can thus be seen as a new type of cavity. It is a way to suppress the
guided mode of a dielectric slab.


title:
Separation of the strain and finite size effect on the ferromagnetic
  properties of La_{0.5}Sr_{0.5}CoO_3 thin films

abstract:
  The ferromagnetic properties of epitaxial La$_{0.5}$Sr$_{0.5}$CoO$_3$ thin
films have been studied. The magnetic transition is affected by both strain and
finite thickness. We have used a series of films of different thickness and on
different substrates in order to quantitatively determine the change in Curie
temperature contributed by each effect. The phase diagram of T$_C$ versus
in-plane strain suggests that the ferromagnetic transition temperature is
suppressed by tensile strain and enhanced by compressive strain. The general
method of separating strain and finite thickness effects should be applicable
to any ordering phase transition in thin films.


title:
Maty's Biography of Abraham De Moivre, Translated, Annotated and
  Augmented

abstract:
  November 27, 2004, marked the 250th anniversary of the death of Abraham De
Moivre, best known in statistical circles for his famous large-sample
approximation to the binomial distribution, whose generalization is now
referred to as the Central Limit Theorem. De Moivre was one of the great
pioneers of classical probability theory. He also made seminal contributions in
analytic geometry, complex analysis and the theory of annuities. The first
biography of De Moivre, on which almost all subsequent ones have since relied,
was written in French by Matthew Maty. It was published in 1755 in the Journal
britannique. The authors provide here, for the first time, a complete
translation into English of Maty's biography of De Moivre. New material, much
of it taken from modern sources, is given in footnotes, along with numerous
annotations designed to provide additional clarity to Maty's biography for
contemporary readers.


title: PAC Fields over Finitely Generated Fields

abstract:
  We prove the following theorem for a finitely generated field $K$: Let $M$ be
a Galois extension of $K$ which is not separably closed. Then $M$ is not PAC
over $K$.


title: The dynamical viability of scalar-tensor gravity theories

abstract:
  We establish the dynamical attractor behavior in scalar-tensor theories of
dark energy, providing a powerful framework to analyze classes of theories,
predicting common evolutionary characteristics that can be compared against
cosmological constraints. In the Jordan frame the theories are viewed as a
coupling between a scalar field, \Phi, and the Ricci scalar, R, F(\Phi)R. The
Jordan frame evolution is described in terms of dynamical variables m \equiv
d\ln F/d\ln \Phi and r \equiv -\Phi F/f, where F(\Phi) = d f(\Phi)/d\Phi. The
evolution can be alternatively viewed in the Einstein frame as a general
coupling between scalar dark energy and matter, \beta. We present a complete,
consistent picture of evolution in the Einstein and Jordan frames and consider
the conditions on the form of the coupling F and \beta required to give the
observed cold dark matter (CDM) dominated era that transitions into a late time
accelerative phase, including transitory accelerative eras that have not
previously been investigated. We find five classes of evolutionary behavior of
which four are qualitatively similar to those for f(R) theories (which have
\beta=1/2). The fifth class exists only for |\beta| < \sqrt{3}/4, i.e. not for
f(R) theories. In models giving transitory late time acceleration, we find a
viable accelerative region of the (r,m) plane accessible to scalar-tensor
theories with any coupling, \beta (at least in the range |\beta| \leq 1/2,
which we study in detail), and an additional region open only to theories with
|\beta| < \sqrt{3}/4.


title:
Spectral evolution of GRB 060904A observed with Swift and Suzaku --
  Possibility of Inefficient Electron Acceleration

abstract:
  We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku
satellites. We found rapid spectral softening during both the prompt tail phase
and the decline phase of an X-ray flare in the BAT and XRT data. The observed
spectra were fit by power-law photon indices which rapidly changed from $\Gamma
= 1.51^{+0.04}_{-0.03}$ to $\Gamma = 5.30^{+0.69}_{-0.59}$ within a few hundred
seconds in the prompt tail. This is one of the steepest X-ray spectra ever
observed, making it quite difficult to explain by simple electron acceleration
and synchrotron radiation. Then, we applied an alternative spectral fitting
using a broken power-law with exponential cutoff (BPEC) model. It is valid to
consider the situation that the cutoff energy is equivalent to the synchrotron
frequency of the maximum energy electrons in their energy distribution. Since
the spectral cutoff appears in the soft X-ray band, we conclude the electron
acceleration has been inefficient in the internal shocks of GRB 060904A. These
cutoff spectra suddenly disappeared at the transition time from the prompt tail
phase to the shallow decay one. After that, typical afterglow spectra with the
photon indices of 2.0 are continuously and preciously monitored by both XRT and
Suzaku/XIS up to 1 day since the burst trigger time. We could successfully
trace the temporal history of two characteristic break energies (peak energy
and cutoff energy) and they show the time dependence of $\propto t^{-3} \sim
t^{-4}$ while the following afterglow spectra are quite stable. This fact
indicates that the emitting material of prompt tail is due to completely
different dynamics from the shallow decay component. Therefore we conclude the
emission sites of two distinct phenomena obviously differ from each other.


title: Asymmetric quantum error correction via code conversion

abstract:
  In many physical systems it is expected that environmental decoherence will
exhibit an asymmetry between dephasing and relaxation that may result in qubits
experiencing discrete phase errors more frequently than discrete bit errors. In
the presence of such an error asymmetry, an appropriately asymmetric quantum
code - that is, a code that can correct more phase errors than bit errors -
will be more efficient than a traditional, symmetric quantum code. Here we
construct fault tolerant circuits to convert between an asymmetric subsystem
code and a symmetric subsystem code. We show that, for a moderate error
asymmetry, the failure rate of a logical circuit can be reduced by using a
combined symmetric asymmetric system and that doing so does not preclude
universality.


title: Pseudo-Dirac Bino Dark Matter

abstract:
  While the bino-dominated lightest neutralino of the minimal supersymmetric
Standard Model (MSSM) is an interesting and widely-studied candidate of the
dark matter, the p-wave suppression of its annihilation cross section requires
fine-tunings of the MSSM spectra to be consistent with WMAP observations. We
propose pseudo-Dirac bino that arises in theories with D-type
supersymmetry-breaking as an intriguing alternative candidate of dark matter.
The pseudo-Dirac nature of the bino gives a natural mechanism of enhanced
co-annihilation because these two states are degenerate in the absence of
electroweak symmetry breaking. In addition, the lightest state can be
consistent with limits of direct detection experiments because of the lack of
vector interactions, as with the case of the MSSM bino.


title: Nematic cells with defect-patterned alignment layers

abstract:
  Using Monte Carlo simulations of the Lebwohl--Lasher model we study the
director ordering in a nematic cell where the top and bottom surfaces are
patterned with a lattice of $\pm 1$ point topological defects of lattice
spacing $a$. We find that the nematic order depends crucially on the ratio of
the height of the cell $H$ to $a$. When $H/a \gtrsim 0.9$ the system is very
well--ordered and the frustration induced by the lattice of defects is relieved
by a network of half--integer defect lines which emerge from the point defects
and hug the top and bottom surfaces of the cell. When $H/a \lesssim 0.9$ the
system is disordered and the half--integer defect lines thread through the cell
joining point defects on the top and bottom surfaces. We present a simple
physical argument in terms of the length of the defect lines to explain these
results. To facilitate eventual comparison with experimental systems we also
simulate optical textures and study the switching behavior in the presence of
an electric field.


title:
Ultrashort intense-field optical vortices produced with laser-etched
  mirrors

abstract:
  We introduce a simple and practical method to create ultrashort intense
optical vortices for applications involving high-intensity lasers. Our method
utilizes femtosecond laser pulses to laser-etch grating lines into
laser-quality gold mirrors. These grating lines holographically encode an
optical vortex. We derive mathematical equations for each individual grating
line to be etched, for any desired (integer) topological charge. We investigate
the smoothness of the etched grooves. We show that they are smooth enough to
produce optical vortices with an intensity that is only a few percent lower
than in the ideal case. We demonstrate that the etched gratings can be used in
a folded version of our 2f-2f setup [Mariyenko et al., Opt. Express 19, 7599
(2005)] to compensate angular dispersion. Lastly, we show that the etched
gratings withstand intensities of up to 10^12 W/cm2.


title:
Evidence of orbital reconstruction at interfaces in La0.67Sr0.33MnO3
  films

abstract:
  Electronic properties of transition metal oxides at interfaces are influenced
by strain, electric polarization and oxygen diffusion. Linear dichroism (LD)
x-ray absorption, diffraction, transport and magnetization on thin
La0.7Sr0.3MnO3 films, allow identification of a peculiar universal interface
effect. We report the LD signature of preferential 3d-eg(3z2-r2) occupation at
the interface, suppressing the double exchange mechanism. This surface orbital
reconstruction is opposite of that favored by residual strain and independent
of dipolar fields, chemical nature of the substrate and capping.


title: A Conversation with Robert V. Hogg

abstract:
  Robert Vincent Hogg was born on November 8, 1924 in Hannibal, Missouri. He
earned a Ph.D. in statistics at the University of Iowa in 1950, where his
advisor was Allen Craig. Following graduation, he joined the mathematics
faculty at the University of Iowa. He was the founding Chair when the
Department of Statistics was created at Iowa in 1965 and he served in that
capacity for 19 years. At Iowa he also served as Chair of the Quality
Management and Productivity Program and the Hanson Chair of Manufacturing
Productivity. He became Professor Emeritus in 2001 after 51 years on the Iowa
faculty. He is a Fellow of the Institute of Mathematical Statistics and the
American Statistical Association plus an Elected Member of the International
Statistical Institute. He was President of the American Statistical Association
(1988) and chaired two of its winter conferences (1992, 1994). He received the
ASA's Founder's Award (1991) and the Gottfried Noether Award (2001) for
contributions to nonparametric statistics. His publications through 1996 are
described in Communications in Statistics--Theory and Methods (1996),
2467--2481. This interview was conducted on April 14, 2004 at the Department of
Statistics, University of Florida, Gainesville, Florida, and revised in the
summer of 2006.


title:
Absence of local magnetic moments in Ru and Rh impurities and clusters
  on Ag(100) and Pt(997)

abstract:
  The magnetism of quench-condensed Ru and Rh impurities and metal films on
Ag(100) and Pt(997) has been studied using x-ray magnetic circular dichroism.
In the coverage range between 0.22 ML and 2.0 ML no dichroic signal was
detected at the M3,2 absorption edges of Ru on Ag(100) at a temperature of 5 K
in the presence of an applied magnetic field. The same was found for coverages
between 0.12 ML and 0.5 ML of Rh on Ag(100) and Pt(997). It is concluded that
the magnetic moments of single impurities, small clusters of various shape and
monolayers of the 4d metals are below the detection limit of 0.04 muB per atom.
These results provide an unambiguous determination of the local magnetic moment
of Ru and Rh deposited on nonmagnetic transition-metal surfaces, which are in
contrast with theoretical predictions.


title: Geometry reconstruction of fluorescence detectors revisited

abstract:
  The experimental technique of fluorescence light observation is used in
current and planned air shower experiments that aim at understanding the origin
of ultra-high energy cosmic rays. In the fluorescence technique, the geometry
of the shower is reconstructed based on the correlation between viewing angle
and arrival time of the signals detected by the telescope. The signals are
compared to those expected for different shower geometries and the best-fit
geometry is determined. The calculation of the expected signals is usually
based on a relatively simple function which is motivated by basic geometrical
considerations. This function is based on certain assumptions on the processes
of light emission and propagation through the atmosphere. For instance, the
fluorescence light is assumed to propagate with vacuum speed of light. We
investigate the validity of these assumptions and provide corrections that can
be used in the geometry reconstruction. The impact on reconstruction parameters
is studied. The results are also relevant for hybrid observations where the
shower is registered simultaneously by fluorescence and surface detectors.


title: The Lie algebra perturbation lemma

abstract:
  Let g be a differential graded Lie algebra and suppose given a contraction of
chain complexes of g onto a general chain complex M. We show that the data
determine an sh-Lie algebra structure on M, that is, a coalgebra perturbation
of the coalgebra differential on the cofree coaugmented differential graded
cocommutative coalgebra S' on the suspension of M, a Lie algebra twisting
cochain from the perturbed coalgebra S" to the given Lie algebra g, and an
extension of this Lie algebra twisting cochain to a contraction of chain
complexes from the Cartan-Chevalley-Eilenberg coalgebra on g onto S" which is
natural in the data. This extends a result established in a joint paper of the
author with J. Stashef [Forum math. 14 (2002), 847-868, math.AG/9906036] where
only the particular where M is the homology of g has been explored.


title:
Path-Integral Formulation of Pseudo-Hermitian Quantum Mechanics and the
  Role of the Metric Operator

abstract:
  We provide a careful analysis of the generating functional in the path
integral formulation of pseudo-Hermitian and in particular PT-symmetric quantum
mechanics and show how the metric operator enters the expression for the
generating functional.


title:
Constraining the nature of High Frequency Peakers. I. The spectral
  variability

abstract:
  We investigate the spectral characteristics of 51 candidate High Frequency
Peakers (HFPs), from the ``bright'' HFP sample, in order to determine the
nature of each object, and to obtain a smaller sample of genuine young radio
sources. Simultaneous multi-frequency VLA observations carried out at various
epochs have been used to detect flux density and spectral shape variability in
order to pinpoint contaminant objects, since young radio sources are not
expected to be significantly variable on such a short time-scale. From the
analysis of the spectral variability we find 13 contaminant objects, 11
quasars, 1 BL Lac, and 1 unidentified object, which we have rejected from the
sample of candidate young radio sources. The 6 years elapsed between the first
and latest observing run are not enough to detect any substantial evolution of
the overall spectrum of genuine, non variable, young radio sources. If we also
consider the pc-scale information, we find that the total radio spectrum we
observe is the result of the superposition of the spectra of different regions
(lobes, hot-spots, core, jets), instead of a single homogeneous radio
component. This indicates that the radio source structure plays a relevant role
in determining the spectral shape also in the rather common case in which the
morphology appears unresolved even on high-resolution scales.


title: On a characterization of PPT states

abstract:
  We present two different descriptions of positive partially transposed (PPT)
states. One is based on the theory of positive maps while the second
description provides a characterization of PPT states in terms of Hilbert space
vectors. Our note is based on our previous results.


title: Gaps in the differential forms spectrum on cyclic coverings

abstract:
  We are interested in the spectrum of the Hodge-de Rham operator on a cyclic
covering $X$ over a compact manifold $M$ of dimension $n+1$. Let $\Sigma$ be a
hypersurface in $M$ which does not disconnect $M$ and such that $M-\Sigma$ is a
fundamental domain of the covering. If the cohomology group $H^{n/2 (\Sigma)$
is trivial, we can construct for each $N \in \N$ a metric $g=g_N$ on $M$, such
that the Hodge-de Rham operator on the covering $(X,g)$ has at least $N$ gaps
in its (essential) spectrum. If $H^{n/2}(\Sigma) \ne 0$, the same statement
holds true for the Hodge-de Rham operators on $p$-forms provided $p \notin
\{n/2,n/2+1\}$.


title: Atomic-charge distribution in glasses by terahertz spectroscopy

abstract:
  It is demonstrated that the width of the uncorrelated atomic-charge
distribution in glasses can be extracted from the frequency dependence of the
coupling coefficient for the far-infrared absorption measured experimentally by
the time-domain terahertz spectroscopy technique. This value for As2S3 glass is
found to be 0.12 (e). A density functional theory-based tight-binding molecular
dynamics model of As2S3 glass qualitatively supports these findings.


title: Unifying inflation and dark matter with neutrino masses

abstract:
  We propose a simple model where a {\it gauge invariant inflaton} is
responsible for cosmic inflation and generates the seed for structure
formation, while its relic {\it thermal} abundance explains the missing matter
of the universe in the form of cold dark matter. The inflaton self-coupling
also explains the observed neutrino masses. All the virtues can be attained in
a minimal extension of the Standard Model gauge group around the TeV scale. We
can also unveil these properties of an inflaton in forthcoming space and ground
based experiments.


title: Lectures on Nongeometric Flux Compactifications

abstract:
  These notes present a pedagogical review of nongeometric flux
compactifications. We begin by reviewing well-known geometric flux
compactifications in Type II string theory, and argue that one must include
nongeometric "fluxes" in order to have a superpotential which is invariant
under T-duality. Additionally, we discuss some elementary aspects of the
worldsheet description of nongeometric backgrounds. This review is based on
lectures given at the 2007 RTN Winter School at CERN.


title: Transient x-ray absorption spectroscopy of hydrated halogen atom

abstract:
  Time-resolved x-ray absorption spectroscopy monitors the transient species
generated by one-photon detachment of an electron from aqueous bromide.
Hydrated bromine atoms with a lifetime of ca. 17 ns were observed, nearly half
of which react with excess Br- to form Br2-. The K-edge spectra of the Br atom
and Br2- anion exhibit distinctive resonant transitions that are absent for the
Br- precursor. The absorption spectra indicate that the solvent shell around a
Br0 atom is defined primarily by hydrophobic interactions, in agreement with a
Monte Carlo simulation of the solvent structure.