title: Imprint of Distortions in the Oort Cloud on the CMB Anisotropies

abstract:
  We study the effect of a close encounter of a passing star on the shape of
the inner Oort Cloud, using the impulse approximation. The deviation of the
perturbed Oort Cloud from sphericity adds angular fluctuations to the
brightness of the Cosmic Microwave Background (CMB) due to thermal emission by
the comets. An encounter with a solar-mass star at an impact parameter of $1750
\au$, as expected based on the abundance and velocity dispersion of stars in
the solar neighborhood, leads to a quadrupole moment in the square of the
fractional CMB intensity fluctuation of $C_2 = 4.5 \times 10^{-15}, 6.7 \times
10^{-12}, 1.1 \times 10^{-9}$ at $\nu = 30, 353, 545 \GHz$ (these being the
frequency bands of the upcoming Planck satellite). We also quantify the
quadrupole spectral distortions produced by the Scattered Disc, which will
exist regardless of any perturbation and the subsequent shape of the Oort
Cloud. For comparison, the square fractional temperature fluctuation quadrupole
moment predicted by the current cosmological model is $C_2 = 1.76 \times
10^{-10}$, which corresponds to fluctuations in the CMB intensity of $C_2 = 2.9
\times 10^{-10}, 6.8 \times 10^{-9}, 1.6 \times 10^{-8}$ at $\nu = 30, 353, 545
\GHz$. Finally, we discuss how a measurement of the anisotropic spectral
distortions could be used to constrain the trajectory of the closest stellar
fly-by.


title:
A new method to derive star formation histories of galaxies from their
  star cluster distributions

abstract:
  Star formation happens in a clustered way which is why the star cluster
population of a particular galaxy is closely related to the star formation
history of this galaxy. From the probabilistic nature of a mass function
follows that the mass of the most-massive cluster of a complete population,
M_max, has a distribution with the total mass of the population as a parameter.
The total mass of the population is connected to the star formation rate (SFR)
by the length of a formation epoch.
  Since due to evolutionary effects only massive star clusters are observable
up to high ages it is convenient to use this M_max(SFR) relation for the
reconstruction of a star formation history. The age-distribution of the
most-massive clusters can therefore be used to constrain the star formation
history of a galaxy. The method, including an assessment of the inherent
uncertainties, is introduced with this contribution, while following papers
will apply this method to a number of galaxies.


title:
Anomalous relaxation in complex systems: from stretched to compressed
  exponentials

abstract:
  We attempt to give a bird's eye view of the physical mechanisms leading to
anomalous relaxation, and the relation of this phenomenon with anomalous
diffusion and transport. Whereas in some cases these two notions are indeed
deeply related, this needs not to be the case. We review several models for
stretched exponential relaxation (diffusion in traps, broad distribution of
relaxation times, two-step relaxation) and insist on the physical
interpretation to be given to the stretching exponent $\beta$. We then discuss
compressed exponentials which have been recently observed in a variety of
systems, from soft glassy materials to granular packs. We describe a model
where slow rearrangement events occur randomly in space and create long ranged
elastics strains, leading to $\beta=3/2$.


title: Topological spin liquid on the hyper-kagome lattice of Na_4Ir_3O_8

abstract:
  Recent experiments on the "hyper-kagome" lattice system Na$_4$Ir$_3$O$_8$
have demonstrated that it is a rare example of a three dimensional spin-1/2
frustrated antiferromagnet. We investigate the role of quantum fluctuations as
the primary mechanism lifting the macroscopic degeneracy inherited by classical
spins on this lattice. In the semi-classical limit we predict, based on large-N
calculations, that an unusual $\vec q=0$ coplaner magnetically ordered ground
state is stabilized with no local "weather vane" modes. This phase melts in the
quantum limit and a gapped topological Z$_2$ spin liquid phase emerges. In the
vicinity of this quantum phase transition, we study the dynamic spin structure
factor and comment on the relevance of our results for future neutron
scattering experiments.


title: From semiconductors to quantum gravity: to centenary of Matvei Bronstein

abstract:
  Investigation of the many-body condensed-matter systems allows us to connect
the microscopic physics at the atomic energy scale and the macroscopic physics
emerging in the low-energy corner. It gives some hints on the mechanisms of the
formation of the physical laws which our Universe obeys. The paper is devoted
to the centenary of Matvei Petrovich Bronstein.

categories: gr-qc cond-mat.str-el hep-ph physics.hist-ph


title: Classically normal pure states

abstract:
  A pure state f of a von Neumann algebra M is called classically normal if f
is normal on any von Neumann subalgebra of M on which f is multiplicative.
Assuming the continuum hypothesis, a separably represented von Neumann algebra
M has classically normal, singular pure states iff there is a central
projection p in M such that Mp is a factor of type I_\infty, II, or III.


title: A map of the day-night contrast of the extrasolar planet HD 189733b

abstract:
  "Hot Jupiter" extrasolar planets are expected to be tidally locked because
they are close (<0.05 astronomical units, where 1 AU is the average Sun-Earth
distance) to their parent stars, resulting in permanent daysides and
nightsides. By observing systems where the planet and star periodically eclipse
each other, several groups have been able to estimate the temperatures of the
daysides of these planets. A key question is whether the atmosphere is able to
transport the energy incident upon the dayside to the nightside, which will
determine the temperature at different points on the planet's surface. Here we
report observations of HD 189733, the closest of these eclipsing planetary
systems, over half an orbital period, from which we can construct a 'map' of
the distribution of temperatures. We detected the increase in brightness as the
dayside of the planet rotated into view. We estimate a minimum brightness
temperature of 973 +/- 33 K and a maximum brightness temperature of 1212 +/- 11
K at a wavelength of 8 microns, indicating that energy from the irradiated
dayside is efficiently redistributed throughout the atmosphere, in contrast to
a recent claim for another hot Jupiter. Our data indicate that the peak
hemisphere-integrated brightness occurs 16$\pm$6 degrees before opposition,
corresponding to a hot spot shifted east of the substellar point. The secondary
eclipse (when the planet moves behind the star) occurs 120 +/- 24 s later than
predicted, which may indicate a slightly eccentric orbit.


title: Debye screening in strongly coupled N=4 supersymmetric Yang-Mills plasma

abstract:
  Using the AdS/CFT correspondence, we examine the behavior of correlators of
Polyakov loops and other operators in N=4 supersymmetric Yang-Mills theory at
non-zero temperature. The implications for Debye screening in this strongly
coupled non-Abelian plasma, and comparisons with available results for thermal
QCD, are discussed.


title:
Decoherence of a driven multilevel quantum system interacting with a
  multi-bath reservoir

abstract:
  A general theory is presented for the treatment of decoherence of a
multilevel quantum system (with many degrees of freedom) interacting with
multi-bath reservoir and driven by ac fields. In this approach, the system is
described by a reduced density operator and the multi-bath reservoir is
characterized by a number of spectral densities. The reduced density operator
is governed by the master equation in which the effect of ac driving fields and
the leakage to non-computational states are included. The theory is applied to
the study of decoherence of a two-dimensional (2D) SQUID flux qubit coupled to
control and readout circuits. The predicted results are in very good agreement
with available experimental results in the absence of driving fields and with
the analytic results of a dissipative two-level system in the presence of weak
driving fields. The relaxation and decoherence times versus the parameters and
temperature of the control and readout circuits are also explored in details to
facilitate the optimization of the 2D SQUID qubit.


title: Energy conditions and current acceleration of the universe

abstract:
  The energy conditions provide a very promising model-independent study of the
current acceleration of the universe. However, in order to connect these
conditions with observations, one often needs first to integrate them, and then
find the corresponding constraints on some observational variables, such as the
distance modulus. Those integral forms can be misleading, and great caution is
needed when one interprets them physically. A typical example is that the
transition point of the deceleration parameter $q(z)$ is at about $z \simeq
0.76$ in the $\Lambda$CDM model. However, with the same model when we consider
the dimensionless Hubble parameter $E(z)$, which involves the integration of
$q(z)$, we find that $E(z)$ does not cross the line of $q(z) = 0$ before $z =
2$. Therefore, to get the correct result, we cannot use the latter to determine
the transition point. With these in mind, we carefully study the constraints
from the energy conditions, and find that, among other things, the current
observational data indeed strongly indicate that our universe has ocne
experienced an accelerating expansion phase between the epoch of galaxy
formation and the present.


title:
Avalanches Injecting Flux into the Central Hole of a Superconducting
  MgB2 Ring

abstract:
  Magneto-optical imaging was used to observe dendritic flux avalanches
connecting the outer and inner edges of a ring-shaped superconducting MgB2
film. Such avalanches create heated channels across the entire width of the
ring, and inject large amounts of flux into the central hole. By measuring the
injected flux and the corresponding reduction of current, which is typically
15%, we estimate the maximum temperature in the channel to be 100 K, and the
duration of the process to be on the order of a microsecond. Flux creep
simulations reproduce all the observed features in the current density before
and after injection events.


title: The alternating sign matrix polytope

abstract:
  We define the alternating sign matrix polytope as the convex hull of nxn
alternating sign matrices and prove its equivalent description in terms of
inequalities. This is analogous to the well known result of Birkhoff and von
Neumann that the convex hull of the permutation matrices equals the set of all
nonnegative doubly stochastic matrices. We count the facets and vertices of the
alternating sign matrix polytope and describe its projection to the
permutohedron as well as give a complete characterization of its face lattice
in terms of modified square ice configurations. Furthermore we prove that the
dimension of any face can be easily determined from this characterization.


title:
Cellular Systems with Full-Duplex Amplify-and-Forward Relaying and
  Cooperative Base-Stations

abstract:
  In this paper the benefits provided by multi-cell processing of signals
transmitted by mobile terminals which are received via dedicated relay
terminals (RTs) are assessed. Unlike previous works, each RT is assumed here to
be capable of full-duplex operation and receives the transmission of adjacent
relay terminals. Focusing on intra-cell TDMA and non-fading channels, a
simplified uplink cellular model introduced by Wyner is considered. This
framework facilitates analytical derivation of the per-cell sum-rate of
multi-cell and conventional single-cell receivers. In particular, the analysis
is based on the observation that the signal received at the base stations can
be interpreted as the outcome of a two-dimensional linear time invariant
system. Numerical results are provided as well in order to provide further
insight into the performance benefits of multi-cell processing with relaying.


title: The Measurement of Time

abstract:
  We present a definition of time measurement based on high energy photons and
the fundamental length scale, and show that, for macroscopic time, it is in
accord with the Lorentz transformation of special relativity. To do this we
define observer in a different way than in special relativity.


title: Charmless Hadronic B Decays at BaBar

abstract:
  We present recent results on charmless hadronic B decays using data collected
by the BaBar detector at the PEP-II asymmetric-energy e+e- collider at the
Stanford Linear Accelerator Center. We report measurements of branching
fractions and charge asymmetries in several charmless two-body, three-body, and
quasi-two-body decay modes. We also report measurements of polarization in
charmless B decays to exclusive final states with two vector mesons.


title: Qubit metrology and decoherence

abstract:
  Quantum properties of the probes used to estimate a classical parameter can
be used to attain accuracies that beat the standard quantum limit. When qubits
are used to construct a quantum probe, it is known that initializing $n$ qubits
in an entangled "cat state," rather than in a separable state, can improve the
measurement uncertainty by a factor of $1/\sqrt{n}$. We investigate how the
measurement uncertainty is affected when the individual qubits in a probe are
subjected to decoherence. In the face of such decoherence, we regard the rate
$R$ at which qubits can be generated and the total duration $\tau$ of a
measurement as fixed resources, and we determine the optimal use of
entanglement among the qubits and the resulting optimal measurement uncertainty
as functions of $R$ and $\tau$.


title: Conjugate points in Euler's elastic problem

abstract:
  For the classical Euler's elastic problem, conjugate points are described.
Inflectional elasticae admit the first conjugate point between the first and
the third inflection points. All the rest elasticae do not have conjugate
points.


title: Gravity duals of half-BPS Wilson loops

abstract:
  We explicitly construct the fully back-reacted half-BPS solutions in Type IIB
supergravity which are dual to Wilson loops with 16 supersymmetries in
$\mathcal{N}=4$ super Yang-Mills. In a first part, we use the methods of a
companion paper to derive the exact general solution of the half-BPS equations
on the space $AdS_2 \times S^2 \times S^4 \times \Sigma$, with isometry group
$SO(2,1)\times SO(3) \times SO(5)$ in terms of two locally harmonic functions
on a Riemann surface $\Sigma$ with boundary. These solutions, generally, have
varying dilaton and axion, and non-vanishing 3-form fluxes. In a second part,
we impose regularity and topology conditions. These non-singular solutions may
be parametrized by a genus $g \geq 0$ hyperelliptic surface $\Sigma$, all of
whose branch points lie on the real line. Each genus $g$ solution has only a
single asymptotic $AdS_5 \times S^5$ region, but exhibits $g$ homology
3-spheres, and an extra $g$ homology 5-spheres, carrying respectively RR 3-form
and RR 5-form charges. For genus 0, we recover $AdS_5 \times S^5$ with 3 free
parameters, while for genus $g \geq 1$, the solution has $2g+5$ free
parameters. The genus 1 case is studied in detail. Numerical analysis is used
to show that the solutions are regular throughout the $g=1$ parameter space.
Collapse of a branch cut on $\Sigma$ subtending either a homology 3-sphere or a
homology 5-sphere is non-singular and yields the genus $g-1$ solution. This
behavior is precisely expected of a proper dual to a Wilson loop in gauge
theory.


title:
An estimation of single and double diffractive heavy flavour production
  in hadron-hadron colliders

abstract:
  Results from a phenomenological analysis for diffractive hadroproduction of
heavy flavors at high energies are reported. Diffractive production of charm,
bottom and top are calculated using Regge factorization, taking into account
recent experimental determination of the diffractive parton density functions
in Pomeron by the H1 Collaboration at DESY-HERA. In addition, multiple-Pomeron
corrections are considered through the rapidity gap survival probability
factor. We give numerical predictions for single diffractive as well as double
Pomeron exchange (DPE) cross sections, which agree with the available data for
diffractive production of charm and beauty. We make estimates which could be
compared to future measurements at the LHC.


title: Current constraints on interacting holographic dark energy

abstract:
  Although there is mounting observational evidence that the cosmic expansion
is undergoing a late-time acceleration, the physical mechanism behind such a
phenomenon is yet unknown. In this paper, we investigate a holographic dark
energy (HDE) model with interaction between the components of the dark sector
in the light of current cosmological observations. We use both the new
\emph{gold} sample of 182 type Ia supernovae (SNe Ia) and the 192 SNe Ia
ESSENCE data, the baryon acoustic oscillation measurement from the Sloan
Digital Sky Survey and the shift parameter from the three-year Wilkinson
Microwave Anisotropy Probe data. In agreement with previous results, we show
that these observations suggest a very weak coupling or even a noninteracting
HDE. The phantom crossing behavior in the context of these scenarios is also
briefly discussed.


title:
The Mass Assembly History of Spheroidal Galaxies: Did Newly-Formed
  Systems Arise Via Major Mergers?

abstract:
  We examine the properties of a morphologically-selected sample of 0.4<z<1.0
spheroidal galaxies in the GOODS fields in order to ascertain whether their
increase in abundance with time arises primarily from mergers. To address this
question we determine scaling relations between the dynamical mass determined
from stellar velocity dispersions, and the stellar mass determined from optical
and infrared photometry. We exploit these relations across the larger sample
for which we have stellar masses in order to construct the first statistically
robust estimate of the evolving dynamical mass function over 0<z<1. The trends
observed match those seen in the stellar mass functions of Bundy et al. 2005
regarding the top-down growth in the abundance of spheroidal galaxies. By
referencing our dynamical masses to the halo virial mass we compare the growth
rate in the abundance of spheroidals to that predicted by the assembly of dark
matter halos. Our comparisons demonstrate that major mergers do not fully
account for the appearance of new spheroidals since z~1 and that additional
mechanisms, such as morphological transformations, are required to drive the
observed evolution.


title: Secondary Characteristic Classes on Loop Spaces

abstract:
  A Riemannian metric on a manifold M induces a family of Riemannian metrics on
the loop space LM depending on a Sobolev space parameter s. The connection and
curvature forms of these metrics take values in pseudodifferential operators.
We develop a theory of Wodzicki-Chern-Simons classes using the s=0, 1
connections and the Wodzicki residue. These classes distinguish the smooth
homotopy type of some circle actions on M = S^2 x S^3, and imply that the
fundamental group of Diff(M) is infinite.


title: Measuring Earth Matter Density and Testing the MSW Theory

abstract:
  In this talk I have raised the question of how the future discovery of
leptonic CP violation can be made robust even at accepting the rather large
current experimental uncertainties in our knowledges of neutrino propagation in
matter. To make progress toward answering the difficult question, I listed ways
to proceed: (1) Obtain tighter constraints on the MSW theory by testing it by
various neutrino experiments. (2) Measure the matter effect in situ, namely
within the experiment for discovering CP violation itself. (3) Uncover leptonic
CP violation in a matter effect free environment. I also reported a step made
toward the above point (2) by taking neutrino factory as a concrete setting; An
accurate in situ measurement of the matter effect looks promising.


title: The Identification of BHB Stars Using GALEX and other photometry

abstract:
  Halo samples that have no kinematic bias have been successfully isolated by
photometric observations. We show that the near-UV (NUV) magnitude of the GALEX
All-Sky Survey can be used, together with Johnson BV magnitudes in a (NUV-V)_0
vs. (B-V)_0 plot, to distinguish blue horizontal branch (BHB) from other A
stars of the same B-V color for 12<V<18. In addition, we use SDSS gr magnitudes
in a (NUV - r)_0 vs. (g-r)_0 plot for 14<r<18. The faint limit will be extended
by ~3 magnitudes for the GALEX Medium-Deep Survey. Attempts to use NUV in
conjunction with 2MASS magnitudes and ROTSE m_r magnitudes did not prove
useful. The (NUV - V)_0 vs. (B-V)_0 plot was used to examine BHB star
candidates of varying quality near the South Galactic Pole. We conclude that
the addition of the GALEX NUV significantly adds to the reliabilty with which
these stars can be identified.


title: Discovery of an Isolated Compact Object at High Galactic Latitude

abstract:
  We report discovery of a compact object at high Galactic latitude. The object
was initially identified as a ROSAT All-Sky Survey Bright Source Catalog X-ray
source, 1RXS J141256.0+792204, statistically likely to possess a high X-ray to
optical flux ratio. Further observations using {\em
  Swift}, Gemini-North, and the Chandra X-ray Observatory refined the source
position and confirmed the absence of any optical counterpart to an X-ray to
optical flux ratio of F_X/F_V > 8700 (3 sigma). Interpretation of 1RXS
J141256.0+792204 -- which we have dubbed Calvera -- as a typical X-ray-dim
isolated neutron star would place it at z ~ 5.1 kpc above the Galactic disk --
in the Galactic halo -- implying that it either has an extreme space velocity
(v_z >~ 5100 km s-1) or has failed to cool according to theoretical
predictions. Interpretations as a persistent anomalous X-ray pulsar, or a
``compact central object'' present conflicts with these classes' typical
properties. We conclude the properties of Calvera are most consistent with
those of a nearby (80 to 260 pc) radio pulsar, similar to the radio millisecond
pulsars of 47 Tuc, with further observations required to confirm this
classification. If it is a millisecond pulsar, it has an X-ray flux equal to
the X-ray brightest millisecond pulsar (and so is tied for highest flux); is
the closest northern hemisphere millisecond pulsar; and is potentially the
closest known millisecond pulsar in the sky, making it an interesting target
for X-ray-study, a radio pulsar timing array, and LIGO.


title: On the Chow ring of the stack of rational nodal curves

abstract:
  The goal of this paper is to compute the rational Chow ring of the stack
consisting of nodal curves of genus 0 with at most 3 nodes: it is a Q-algebra
with 10 generators and 11 relations.


title: Tracking User Attention in Collaborative Tagging Communities

abstract:
  Collaborative tagging has recently attracted the attention of both industry
and academia due to the popularity of content-sharing systems such as
CiteULike, del.icio.us, and Flickr. These systems give users the opportunity to
add data items and to attach their own metadata (or tags) to stored data. The
result is an effective content management tool for individual users. Recent
studies, however, suggest that, as tagging communities grow, the added content
and the metadata become harder to manage due to an ease in content diversity.
Thus, mechanisms that cope with increase of diversity are fundamental to
improve the scalability and usability of collaborative tagging systems. This
paper analyzes whether usage patterns can be harnessed to improve navigability
in a growing knowledge space. To this end, it presents a characterization of
two collaborative tagging communities that target scientific literature:
CiteULike and Bibsonomy. We explore three main directions: First, we analyze
the tagging activity distribution across the user population. Second, we define
new metrics for similarity in user interest and use these metrics to uncover
the structure of the tagging communities we study. The structure we uncover
suggests a clear segmentation of interests into a large number of individuals
with unique preferences and a core set of users with interspersed interests.
Finally, we offer preliminary results that demonstrate that the interest-based
structure of the tagging community can be used to facilitate content usage as
communities scale.


title: More about Superparticle Sum Rules in Grand Unified Theories

abstract:
  Sum rules among superparticle masses are derived under the assumption that
models beyond the MSSM are four-dimensional supersymmetric grand unified
theories or five-dimensional supersymmetric orbifold grand unified theories.
Sfermion sum rules are classified into four types and those sum rules can be
useful probes of the MSSM and beyond.


title: Jet-breaks in the X-ray Light-Curves of Swift GRB Afterglows

abstract:
  In the set of 236 GRB afterglows observed by Swift between January 2005 and
March 2007, we identify 30 X-ray light-curves whose power-law fall-off exhibit
a steepening ("break") at 0.1-10 day after trigger, to a decay steeper than
t^{-1.5}. For most of these afterglows, the X-ray spectral slope and the decay
indices before and after the break can be accommodated by the standard jet
model although a different origin of the breaks cannot be ruled out. In
addition, there are 27 other afterglows whose X-ray light-curves may also
exhibit a late break to a steep decay, but the evidence is not that compelling.
  The X-ray emissions of 38 afterglows decay slower than t^{-1.5} until after 3
day, half of them exhibiting such a slow decay until after 10 day.
  Therefore, the fraction of well-monitored Swift afterglows with potential
jet-breaks is around 60 percent, whether we count only the strongest cases for
each type or all of them. This fraction is comparable to the 75 percent of
pre-Swift afterglows whose optical light-curves displayed similar breaks at ~1
day.
  The properties of the prompt emission of Swift afterglows with light-curve
breaks show the same correlations (peak energy of GRB spectrum with the burst
isotropic output and with burst collimated output) as previously found for
pre-Swift optical afterglows with light-curve breaks (the Amati and Ghirlanda
relations, respectively). However, we find that Ghirlanda relation is largely a
consequence of Amati's and that the use of the jet-break time leads to a
stronger Ghirlanda correlation only when the few outliers to the Amati relation
are included.


title: Periodic oscillations of dark solitons in parabolic potentials

abstract:
  We reformulate the Gross-Pitaevskii equation with an external parabolic
potential as a discrete dynamical system, by using the basis of Hermite
functions. We consider small amplitude stationary solutions with a single node,
called dark solitons, and examine their existence and linear stability.
Furthermore, we prove the persistence of a periodic motion in a neighborhood of
such solutions. Our results are corroborated by numerical computations
elucidating the existence, linear stability and dynamics of the relevant
solutions.


title: Invariants from classical field theory

abstract:
  We introduce a method that generates invariant functions from perturbative
classical field theories depending on external parameters. Applying our methods
to several field theories such as abelian BF, Chern-Simons and 2-dimensional
Yang-Mills theory, we obtain, respectively, the linking number for embedded
submanifolds in compact varieties, the Gauss' and the second Milnor's invariant
for links in S^3, and invariants under area-preserving diffeomorphisms for
configurations of immersed planar curves.


title:
Optical dilution and feedback cooling of a gram-scale oscillator to 6.9
  mK

abstract:
  We report on use of a radiation pressure induced restoring force, the optical
spring effect, to optically dilute the mechanical damping of a 1 gram suspended
mirror, which is then cooled by active feedback (cold damping). Optical
dilution relaxes the limit on cooling imposed by mechanical losses, allowing
the oscillator mode to reach a minimum temperature of 6.9 mK, a factor of
~40000 below the environmental temperature. A further advantage of the optical
spring effect is that it can increase the number of oscillations before
decoherence by several orders of magnitude. In the present experiment we infer
an increase in the dynamical lifetime of the state by a factor of ~200.


title:
Theoretical Analysis of Subthreshold Oscillatory Behaviors in Nonlinear
  Autonomous Systems

abstract:
  We have developed a linearization method to investigate the subthreshold
oscillatory behaviors in nonlinear autonomous systems. By considering firstly
the neuronal system as an example, we show that this theoretical approach can
predict quantitatively the subthreshold oscillatory activities, including the
damping coefficients and the oscillatory frequencies which are in good
agreement with those observed in experiments. Then we generalize the
linearization method to an arbitrary autonomous nonlinear system. The detailed
extension of this theoretical approach is also presented and further discussed.


title:
Residual nuclide formation in 206,207,208,nat-Pb and 209-Bi induced by
  0.04-2.6 GeV Protons as well as in 56-Fe induced by 0.3-2.6 GeV Protons

abstract:
  5972 independent and cumulative yields of radioactive residuals nuclei have
been measured in 55 thin 206,207,208,nat-Pb and 209-Bi targets irradiated by
0.04, 0.07, 0.10, 0.15, 0.25, 0.6, 0.8, 1.2, 1.4, 1.6, and 2.6 GeV protons.
Besides, 219 yields have been measured in 0.3, 0.5, 0.75, 1.0, 1.5, and 2.6 GeV
proton-irradiated 56-Fe target. The protons were extracted from the ITEP U-10
synchrotron. The measured data are compared with experimental results obtained
elsewhere and with theoretical calculations by LAHET, MCNPX, CEM03, LAQGSM03,
CASCADE, CASCADO, and LAHETO codes. The predictive power was found to be
different for each of the codes tested, but was satisfactory on the whole in
the case of spallation products. At the same time, none of the codes can
de-scribe well the product yields throughout the whole product mass range, and
all codes must be further improved.


title:
Satellite Observations of Separator Line Geometry of Three-Dimensional
  Magnetic Reconnection

abstract:
  Detection of a separator line that connects magnetic nulls and the
determination of the dynamics and plasma environment of such a structure can
improve our understanding of the three-dimensional (3D) magnetic reconnection
process. However, this type of field and particle configuration has not been
directly observed in space plasmas. Here we report the identification of a pair
of nulls, the null-null line that connects them, and associated fans and spines
in the magnetotail of Earth using data from the four Cluster spacecraft. With
di and de designating the ion and electron inertial lengths, respectively, the
separation between the nulls is found to be ~0.7di and an associated
oscillation is identified as a lower hybrid wave with wavelength ~ de. This in
situ evidence of the full 3D reconnection geometry and associated dynamics
provides an important step toward to establishing an observational framework of
3D reconnection.


title:
Identification of Very Red Counterparts of SiO Maser and OH/IR Objects
  in the GLIMPSE Survey

abstract:
  Using the 3.6/4.5/5.8/8.0 micron images with 1.2 arcsec pixel resolution from
the Spitzer/GLIMPSE survey, we investigated 23 masing and 18 very red objects
that were not identified in the 2MASS survey. Counterparts for all selected
objects were found in the GLIMPSE images. Color indices in these IR bands
suggest the presence of a high-extinction layer of more than a few tenths of a
solar mass in front of the central star. Furthermore, radio observations in the
SiO and H2O maser lines found characteristic maser-line spectra of the embedded
objects, e.g., the SiO J=1-0 line intensity in the v=2 state stronger than that
of the v=1 state, or very widespread H2O maser emission spectra. This indicates
that these objects are actually enshrouded by very thick circumstellar matter,
some of which cannot be ascribed to the AGB wind of the central star.
Individually interesting objects are discussed, including two newly found water
fountains and an SiO source with nebulosity.


title:
Angles Between Infinite Dimensional Subspaces with Applications to the
  Rayleigh-Ritz and Alternating Projectors Methods

abstract:
  We define angles from-to and between infinite dimensional subspaces of a
Hilbert space, inspired by the work of E. J. Hannan, 1961/1962 for general
canonical correlations of stochastic processes. The spectral theory of
selfadjoint operators is used to investigate the properties of the angles,
e.g., to establish connections between the angles corresponding to orthogonal
complements. The classical gaps and angles of Dixmier and Friedrichs are
characterized in terms of the angles. We introduce principal invariant
subspaces and prove that they are connected by an isometry that appears in the
polar decomposition of the product of corresponding orthogonal projectors.
Point angles are defined by analogy with the point operator spectrum. We bound
the Hausdorff distance between the sets of the squared cosines of the angles
corresponding to the original subspaces and their perturbations. We show that
the squared cosines of the angles from one subspace to another can be
interpreted as Ritz values in the Rayleigh-Ritz method, where the former
subspace serves as a trial subspace and the orthogonal projector of the latter
subspace serves as an operator in the Rayleigh-Ritz method. The Hausdorff
distance between the Ritz values, corresponding to different trial subspaces,
is shown to be bounded by a constant times the gap between the trial subspaces.
We prove a similar eigenvalue perturbation bound that involves the gap squared.
Finally, we consider the classical alternating projectors method and propose
its ultimate acceleration, using the conjugate gradient approach. The
corresponding convergence rate estimate is obtained in terms of the angles. We
illustrate a possible acceleration for the domain decomposition method with a
small overlap for the 1D diffusion equation.


title:
High-energy threshold reaction rates on 0.8 GeV proton-irradiated thick
  Pb-target

abstract:
  This works presents results of activation-aided determination of threshold
reaction rates in 92 209Bi, natPb, 197Au, 181Ta, 169Tm, natIn, 93Nb, 64Zn,
65Cu, 63Cu, 59Co, 19F, and 12C samples and in 121 27Al samples. All the samples
were aligned with the proton beam axis inside and outside the demountable 92-cm
thick Pb target of 15-cm diameter assembled of 23 4-cm thick discs. The samples
were placed on 12 target disks to reproduce the long axis distribution of
protons and neutrons. In June 2006, the target was exposed for 18 hours to a
800-MeV proton beam extracted from the ITEP U-10 accelerator. The proton
fluence and the proton beam shape were determined using the 27Al(p,x)7Be
monitor reaction. The reaction rates were determined by the direct
gamma-spectrometry techniques. In total, 1196 gamma-spectra have been measured,
and about 1500 reaction rates determined. The measured reaction rates were
simulated by the MCNPX code using the following databases: ENDF/B6 for neutrons
below 20 MeV, MENDL2 for 20-100 MeV neutrons, and MENDL2P for proton cross
sections up to 200 MeV. An acceptable agreement of simulations with
experimental data has been found.


title: Recognizing Partial Cubes in Quadratic Time

abstract:
  We show how to test whether a graph with n vertices and m edges is a partial
cube, and if so how to find a distance-preserving embedding of the graph into a
hypercube, in the near-optimal time bound O(n^2), improving previous O(nm)-time
solutions.


title:
Reflected backward SDEs with two barriers under monotonicity and general
  increasing conditions

abstract:
  In this paper, we prove the existence and uniqueness result of the reflected
BSDE with two continuous barriers under monotonicity and general increasing
condition on $y$, with Lipschitz condition on $z$.


title: Small Chvatal rank

abstract:
  We propose a variant of the Chvatal-Gomory procedure that will produce a
sufficient set of facet normals for the integer hulls of all polyhedra {xx : Ax
<= b} as b varies. The number of steps needed is called the small Chvatal rank
(SCR) of A. We characterize matrices for which SCR is zero via the notion of
supernormality which generalizes unimodularity. SCR is studied in the context
of the stable set problem in a graph, and we show that many of the well-known
facet normals of the stable set polytope appear in at most two rounds of our
procedure. Our results reveal a uniform hypercyclic structure behind the
normals of many complicated facet inequalities in the literature for the stable
set polytope. Lower bounds for SCR are derived both in general and for
polytopes in the unit cube.


title: The time evolution of an atom coupled to a thermal radiation field

abstract:
  We study the time evolution of an atom suddenly coupled to a thermal
radiation field. As a simplified model of the atom-electromagnetic field system
we use a system composed by a harmonic oscillator linearly coupled to a scalar
field in the framework of the recently introduced dressed coordinates and
dressed states. We show that the time evolution of the thermal expectation
values for the occupation number operators depend exclusively on the
probabilities associated with the emission and absorption of field quanta. In
particular, the time evolution of the number operator associated with the atom
is given in terms of the probability of remaining in the first excited state
and the decay probabilities from this state by emission of field quanta of
frequencies $\omega_k$. Also, it is showed that independent of the initial
state of the atom, it thermalizes with the thermal radiation field in a time
scale of the order of the inverse coupling constant.


title:
No Way Back: Maximizing survival time below the Schwarzschild event
  horizon

abstract:
  It has long been known that once you cross the event horizon of a black hole,
your destiny lies at the central singularity, irrespective of what you do.
Furthermore, your demise will occur in a finite amount of proper time. In this
paper, the use of rockets in extending the amount of time before the collision
with the central singularity is examined. In general, the use of such rockets
can increase your remaining time, but only up to a maximum value; this is at
odds with the ``more you struggle, the less time you have'' statement that is
sometimes discussed in relation to black holes. The derived equations are
simple to solve numerically and the framework can be employed as a teaching
tool for general relativity.


title: Detection of Aneuploidy with Digital PCR

abstract:
  The widespread use of genetic testing in high risk pregnancies has created
strong interest in rapid and accurate molecular diagnostics for common
chromosomal aneuploidies. We show here that digital polymerase chain reaction
(dPCR) can be used for accurate measurement of trisomy 21 (Down's Syndrome),
the most common human aneuploidy. dPCR is generally applicable to any
aneuploidy, does not depend on allelic distribution or gender, and is able to
detect signals in the presence of mosaics or contaminating maternal DNA.


title:
Fuzzy Artmap and Neural Network Approach to Online Processing of Inputs
  with Missing Values

abstract:
  An ensemble based approach for dealing with missing data, without predicting
or imputing the missing values is proposed. This technique is suitable for
online operations of neural networks and as a result, is used for online
condition monitoring. The proposed technique is tested in both classification
and regression problems. An ensemble of Fuzzy-ARTMAPs is used for
classification whereas an ensemble of multi-layer perceptrons is used for the
regression problem. Results obtained using this ensemble-based technique are
compared to those obtained using a combination of auto-associative neural
networks and genetic algorithms and findings show that this method can perform
up to 9% better in regression problems. Another advantage of the proposed
technique is that it eliminates the need for finding the best estimate of the
data, and hence, saves time.


title:
Matter density perturbations and effective gravitational constant in
  modified gravity models of dark energy

abstract:
  We derive the equation of matter density perturbations on sub-horizon scales
for a general Lagrangian density f(R, phi, X) that is a function of a Ricci
scalar R, a scalar field phi and a kinetic term X=-(nabla phi)^2/2. This is
useful to constrain modified gravity dark energy models from observations of
large-scale structure and weak lensing. We obtain the solutions for the matter
perturbation delta_m as well as the gravitational potential Phi for some
analytically solvable models. In a f(R) dark energy model with the Lagrangian
density f(R)=alpha R^{1+m}-Lambda, the growth rates of perturbations exhibit
notable differences from those in the standard Einstein gravity unless m is
very close to 0. In scalar-tensor models with the Lagrangian density
f=F(phi)R+2p(phi,X) we relate the models with coupled dark energy scenarios in
the Einstein frame and reproduce the equations of perturbations known in the
current literature by making a conformal transformation. We also estimate the
evolution of perturbations in both Jordan and Einstein frames when the energy
fraction of dark energy is constant during the matter-dominated epoch.


title: Optimal Cache-Oblivious Mesh Layouts

abstract:
  A mesh is a graph that divides physical space into regularly-shaped regions.
Meshes computations form the basis of many applications, e.g. finite-element
methods, image rendering, and collision detection. In one important mesh
primitive, called a mesh update, each mesh vertex stores a value and repeatedly
updates this value based on the values stored in all neighboring vertices. The
performance of a mesh update depends on the layout of the mesh in memory.
  This paper shows how to find a memory layout that guarantees that the mesh
update has asymptotically optimal memory performance for any set of memory
parameters. Such a memory layout is called cache-oblivious. Formally, for a
$d$-dimensional mesh $G$, block size $B$, and cache size $M$ (where
$M=\Omega(B^d)$), the mesh update of $G$ uses $O(1+|G|/B)$ memory transfers.
The paper also shows how the mesh-update performance degrades for smaller
caches, where $M=o(B^d)$.
  The paper then gives two algorithms for finding cache-oblivious mesh layouts.
The first layout algorithm runs in time $O(|G|\log^2|G|)$ both in expectation
and with high probability on a RAM. It uses $O(1+|G|\log^2(|G|/M)/B)$ memory
transfers in expectation and $O(1+(|G|/B)(\log^2(|G|/M) + \log|G|))$ memory
transfers with high probability in the cache-oblivious and disk-access machine
(DAM) models. The layout is obtained by finding a fully balanced decomposition
tree of $G$ and then performing an in-order traversal of the leaves of the
tree. The second algorithm runs faster by almost a $\log|G|/\log\log|G|$ factor
in all three memory models, both in expectation and with high probability. The
layout obtained by finding a relax-balanced decomposition tree of $G$ and then
performing an in-order traversal of the leaves of the tree.


title:
The 2003 Outburst of the X-ray Transient H 1743-322: Comparisons with
  the Black Hole Microquasar XTE J1550-564

abstract:
  The bright X-ray transient H 1743-322 was observed daily by the Rossi X-ray
Timing Explorer (RXTE) during most of its 8-month outburst in 2003. We present
a detailed spectral analysis and a supporting timing analysis of all of these
data, and we discuss the behavior and evolution of the source in terms of the
three principal X-ray states defined by Remillard and McClintock. These X-ray
results are complemented by Very Large Array (VLA) data obtained at six
frequencies that provide quite complete coverage of the entire outburst cycle
at 4.860 GHz and 8.460 GHz. We also present photometric data and finding charts
for the optical counterpart in both outburst and quiescence. We closely compare
H 1743-322 to the well-studied black-hole X-ray transient XTE J1550-564 and
find the behaviors of these systems to be very similar. As reported elsewhere,
both H 1743-322 and XTE J1550-564 are relativistic jet sources and both exhibit
a pair of high-frequency QPO oscillations with a 3:2 frequency ratio. The many
striking similarities between these two sources argue strongly that H 1743-322
is a black hole binary, although presently no dynamical data exist to support
this conclusion.


title:
Equivariant Chow ring and Chern classes of wonderful symmetric varieties
  of minimal rank

abstract:
  We describe the equivariant Chow ring of the wonderful compactification $X$
of a symmetric space of minimal rank, via restriction to the associated toric
variety $Y$. Also, we show that the restrictions to $Y$ of the tangent bundle
$T_X$ and its logarithmic analogue $S_X$ decompose into a direct sum of line
bundles. This yields closed formulae for the equivariant Chern classes of $T_X$
and $S_X$, and, in turn, for the Chern classes of reductive groups considered
by Kiritchenko.


title: Strategies for the Design of a Slide-o-Cam Transmission

abstract:
  The optimization of the pressure angle in a cam-follower transmission is
reported in this paper. This transmission is based on Slide-o-Cam, a cam
mechanism with multiple rollers mounted on a common translating follower. The
design of Slide-o-Cam, a transmission intended to produce a sliding motion from
a turning drive, or vice versa, was reported elsewhere. This transmission
provides pure-rolling motion, thereby reducing the friction of rack-and-pinions
and linear drives. The pressure angle is a suitable performance index for this
transmission because it determines the amount of force transmitted to the load
vs. that transmitted to the machine frame. Two alternative design strategies
are studied, namely, (i) increase the number of lobes on each cam or (ii)
increase the number of cams. This device is intended to replace the current
ball-screws in Orthoglide, a three-DOF parallel robot for the production of
translational motions, currently under development at Ecole Centrale de Nantes
for machining applications.


title:
Regions of Feasible Point-to-Point Trajectories in the Cartesian
  Workspace of Fully-Parallel Manipulators

abstract:
  The goal of this paper is to define the n-connected regions in the Cartesian
workspace of fully-parallel manipulators, i.e. the maximal regions where it is
possible to execute point-to-point motions. The manipulators considered in this
study may have multiple direct and inverse kinematic solutions. The N-connected
regions are characterized by projection, onto the Cartesian workspace, of the
connected components of the reachable configuration space defined in the
Cartesian product of the Cartesian space by the joint space. Generalized octree
models are used for the construction of all spaces. This study is illustrated
with a simple planar fully-parallel manipulator.


title:
The Design of Parallel Kinematic Machine Tools Using Kinetostatic
  Performance Criteria

abstract:
  Most industrial machine tools have a serial kinematic architecture, which
means that each axis has to carry the following one, including its actuators
and joints. High Speed Machining highlights some drawbacks of such
architectures: heavy moving parts require from the machine structure high
stiffness to limit bending problems that lower the machine accuracy, and limit
the dynamic performances of the feed axes. That is why PKMs attract more and
more researchers and companies, because they are claimed to offer several
advantages over their serial counterparts, like high structural rigidity and
high dynamic capacities. Indeed, the parallel kinematic arrangement of the
links provides higher stiffness and lower moving masses that reduce inertia
effects. Thus, PKMs have better dynamic performances. However, the design of a
parallel kinematic machine tool (PKMT) is a hard task that requires further
research studies before wide industrial use can be expected. Many criteria need
to be taken into account in the design of a PKMT. We pay special attention to
the description of kinetostatic criteria that rely on the conditioning of the
Jacobian matrix of the mechanism. The organisation of this paper is as follows:
next section introduces general remarks about PKMs, then is explained why PKMs
can be interesting alternative machine tool designs. Then are presented
existing PKMTs. An application to the design of a small-scale machine tool
prototype developed at IRCCyN is presented at the end of this paper.


title:
Lineshape of the Lambda(1405) Hyperon Measured Through its Sigma0 pion0
  Decay

abstract:
  The pp -> p K+ Y0 reaction has been studied for hyperon masses m(Y0)<1540
MeV/c2 at COSY-Juelich by using a 3.65 GeV/c circulating proton beam incident
on an internal hydrogen target. Final states comprising two protons, one
positively charged kaon and one negatively charged pion have been identified
with the ANKE spectrometer. Such configurations are sensitive to the production
of the ground state Lambda and Sigma0 hyperons as well as the Sigma0(1385) and
Lambda(1405) resonances. Applying invariant- and missing-mass techniques, the
two overlapping excited states could be well separated, though with limited
statistics. The shape and position of the Lambda(1405) distribution,
reconstructed cleanly in the Sigma0 pion0 channel, are similar to those found
from other decay modes and there is no obvious mass shift. This finding
constitutes a challenging test for models that predict Lambda(1405) to be a
two-state resonance.


title: Geometry of limit sets for expansive Markov systems

abstract:
  We describe the geometric and dynamical properties of expansive Markov
systems.


title: Electro-Optic Effect Explanation with Quantum Photonic Model

abstract:
  In this paper, we have explained transverse electro-optic effect by
quantum-photonic model (QPM). This model interpret this effect by
photon-electron interaction in attosecond regime. We simulate applied electric
field on molecule and crystal by Monte-Carlo method in time domain when a light
beam is propagated through the waveguide. We show how the waveguide response to
an optical signal with different wavelengths when a transverse electric field
applied to the waveguide.


title: Non-positive curvature and the Ptolemy inequality

abstract:
  We provide examples of non-locally compact geodesic Ptolemy metric spaces
which are not uniquely geodesic. On the other hand, we show that locally
compact, geodesic Ptolemy metric spaces are uniquely geodesic. Moreover, we
prove that a metric space is CAT(0) if and only if it is Busemann convex and
Ptolemy.


title:
Statistical Mechanics of the Glass Transition in One-Component Liquids
  with Anisotropic Potential

abstract:
  We study a recently introduced model of one-component glass-forming liquids
whose constituents interact with anisotropic potential. This system is
interesting per-se and as a model of liquids like glycerol (interacting via
hydrogen bonds) which are excellent glass formers. We work out the statistical
mechanics of this system, encoding the liquid and glass disorder using
appropriate quasi-particles (36 of them). The theory provides a full
explanation of the glass transition phenomenology, including the identification
of a diverging length scale and a relation between the structural changes and
the diverging relaxation times.


title: Particle-vibration coupling within covariant density functional theory

abstract:
  Covariant density functional theory, which has so far been applied only
within the framework of static and time dependent mean field theory is extended
to include Particle-Vibration Coupling (PVC) in a consistent way. Starting from
a conventional energy functional we calculate the low-lying collective
vibrations in Relativistic Random Phase Approximation (RRPA) and construct an
energy dependent self-energy for the Dyson equation. The resulting
Bethe-Salpeter equation in the particle-hole ($ph$) channel is solved in the
Time Blocking Approximation (TBA). No additional parameters are used and double
counting is avoided by a proper subtraction method. The same energy functional,
i.e. the same set of coupling constants, generates the Dirac-Hartree
single-particle spectrum, the static part of the residual $ph$-interaction and
the particle-phonon coupling vertices. Therefore a fully consistent description
of nuclear excited states is developed. This method is applied for an
investigation of damping phenomena in the spherical nuclei with closed shells
$^{208}$Pb and $^{132}$Sn. Since the phonon coupling terms enrich the RRPA
spectrum with a multitude of $ph\otimes$phonon components a noticeable
fragmentation of the giant resonances is found, which is in full agreement with
experimental data and with results of the semi-phenomenological
non-relativistic approach.


title:
Conjectures on exact solution of three - dimensional (3D) simple
  orthorhombic Ising lattices

abstract:
  We report the conjectures on the three-dimensional (3D) Ising model on simple
orthorhombic lattices, together with the details of calculations for a putative
exact solution. Two conjectures, an additional rotation in the fourth curled-up
dimension and the weight factors on the eigenvectors, are proposed to serve as
a boundary condition to deal with the topologic problem of the 3D Ising model.
The partition function of the 3D simple orthorhombic Ising model is evaluated
by spinor analysis, by employing these conjectures. Based on the validity of
the conjectures, the critical temperature of the simple orthorhombic Ising
lattices could be determined by the relation of KK* = KK' + KK'' + K'K'' or
sinh 2K sinh 2(K' + K'' + K'K''/K) = 1. For a simple cubic Ising lattice, the
critical point is putatively determined to locate exactly at the golden ratio
xc = exp(-2Kc) = (sq(5) - 1)/2, as derived from K* = 3K or sinh 2K sinh 6K = 1.
If the conjectures would be true, the specific heat of the simple orthorhombic
Ising system would show a logarithmic singularity at the critical point of the
phase transition. The spontaneous magnetization and the spin correlation
functions of the simple orthorhombic Ising ferromagnet are derived explicitly.
The putative critical exponents derived explicitly for the simple orthorhombic
Ising lattices are alpha = 0, beta = 3/8, gamma = 5/4, delta = 13/3, eta = 1/8
and nu = 2/3, showing the universality behavior and satisfying the scaling
laws. The cooperative phenomena near the critical point are studied and the
results obtained based on the conjectures are compared with those of the
approximation methods and the experimental findings. The 3D to 2D crossover
phenomenon differs with the 2D to 1D crossover phenomenon and there is a
gradual crossover of the exponents from the 3D values to the 2D ones.


title:
Determination of the size, mass, and density of "exomoons" from
  photometric transit timing variations

abstract:
  Precise photometric measurements of the upcoming space missions allow the
size, mass, and density of satellites of exoplanets to be determined. Here we
present such an analysis using the photometric transit timing variation
($TTV_p$). We examined the light curve effects of both the transiting planet
and its satellite. We define the photometric central time of the transit that
is equivalent to the transit of a fixed photocenter. This point orbits the
barycenter, and leads to the photometric transit timing variations. The exact
value of $TTV_p$ depends on the ratio of the density, the mass, and the size of
the satellite and the planet. Since two of those parameters are independent, a
reliable estimation of the density ratio leads to an estimation of the size and
the mass of the exomoon. Upper estimations of the parameters are possible in
the case when an upper limit of $TTV_p$ is known. In case the density ratio
cannot be estimated reliably, we propose an approximation with assuming equal
densities. The presented photocenter $TTV_p$ analysis predicts the size of the
satellite better than the mass. We simulated transits of the Earth-Moon system
in front of the Sun. The estimated size and mass of the Moon are 0.020
Earth-mass and 0.274 Earth-size if equal densities are assumed. This result is
comparable to the real values within a factor of 2. If we include the real
density ratio (about 0.6), the results are 0.010 Earth-Mass and 0.253
Earth-size, which agree with the real values within 20%.


title: Chromohydrodynamical instabilities induced by relativistic jets

abstract:
  We study the properties of the chromohydrodynamical instabilities induced by
a relativistic jet that crosses the quark-gluon plasma. Assuming that the jet
of particles and the plasma can be described using a hydrodynamical approach,
we derive and discuss the dispersion laws for the unstable collective modes. In
our analysis the chromohydrodynamical equations for the collective modes are
tackled in the linear response approximation. Such an approximation, valid for
short time scales, allows to study in a straightforward way the dependence of
the dispersion laws of the collective modes on the velocity of the jet, on the
magnitude of the momentum of the collective mode and on the angle between these
two quantities. We find that unstable modes arise for velocity of the jet
larger than the speed of the sound of the plasma and only modes with momenta
smaller than a certain values are unstable. Moreover, for ultrarelativistic
velocities of the jet the longitudinal mode becomes stable and the most
unstable modes correspond to relative angles between the velocity of the jet
and momentum of the collective mode larger than $\sim \pi/8$. Our results
suggest an alternative mechanism for the description of the jet quenching
phenomenon, where the jet crossing the plasma loses energy exciting colored
unstable modes.


title:
Couplings between a single massless tensor field with the mixed symmetry
  (3,1) and one vector field

abstract:
  Under the hypotheses of smoothness in the coupling constant, locality,
Lorentz covariance, and Poincare invariance of the deformations, combined with
the preservation of the number of derivatives on each field, the consistent
interactions between a single free massless tensor gauge field with the mixed
symmetry of a two-column Young diagram of the type (3,1) and one Abelian vector
field have been investigated. The computations are done with the help of the
deformation theory based on a cohomological approach, in the context of the
antifield-BRST formalism. The main result is that there exist nontrivial
cross-couplings between these types of fields in five spatiotemporal
dimensions, which break the PT invariance and allow for the deformation of the
gauge transformations of the vector field, but not of the gauge algebra.


title: Creatable Universes

abstract:
  We consider the question of properly defining energy and momenta for non
asymptotic Minkowskian spaces in general relativity. Only spaces of this type,
whose energy, linear 3-momentum, and intrinsic angular momentum vanish, would
be candidates for creatable universes, that is, for universes which could have
arisen from a vacuum quantum fluctuation. Given a universe, we completely
characterize the family of coordinate systems for which one could sensibly say
that this universe is a creatable universe.


title: Bulk Universality and Related Properties of Hermitian Matrix Models

abstract:
  We give a new proof of universality properties in the bulk of spectrum of the
hermitian matrix models, assuming that the potential that determines the model
is globally $C^{2}$ and locally $C^{3}$ function (see Theorem \ref{t:U.t1}).
The proof as our previous proof in \cite{Pa-Sh:97} is based on the orthogonal
polynomial techniques but does not use asymptotics of orthogonal polynomials.
Rather, we obtain the $sin$-kernel as a unique solution of a certain non-linear
integro-differential equation that follows from the determinant formulas for
the correlation functions of the model. We also give a simplified and
strengthened version of paper \cite{BPS:95} on the existence and properties of
the limiting Normalized Counting Measure of eigenvalues. We use these results
in the proof of universality and we believe that they are of independent
interest.


title:
Quasi-elastic neutrino charged-current scattering cross sections on
  oxygen

abstract:
  The charged-current quasi-elastic scattering of muon neutrinos on oxygen
target is computed for neutrino energies between 200 MeV and 2.5 GeV using the
relativistic distorted-wave impulse approximation with relativistic optical
potential, which was earlier successfully applied to describe electron-nucleus
data. We study both neutrino and electron processes and show that the reduced
exclusive cross sections for neutrino and electron scattering are similar. The
comparison with the relativistic Fermi gas model (RFGM), which is widely used
in data analyses of neutrino experiments, shows that the RFGM fails completely
when applied to exclusive cross section data and leads to overestimated values
of inclusive and total cross sections. We also found significant nuclear-model
dependence of exclusive, inclusive and total cross sections for about 1 GeV
energy.


title: Strong-coupling properties of unbalanced Eliashberg superconductors

abstract:
  In this paper we investigate the thermodynamical properties of ``unbalanced''
superconductors, namely, systems where the electron-boson coupling $\lambda$ is
different in the self-energy and in the Cooper channels. This situation is
encountered in a variety of situation, as for instance in d-wave
superconductors. Quite interesting is the case where the pairing in the
self-energy is smaller than the one in the gap equation. In this case we
predict a finite critical value $\lambda_c$ where the superconducting critical
temperature $T_c$ diverges but the zero temperature gap is still finite. The
specific heat, magnetic critical field and the penetration depth are also
evaluated.


title: Anisotropic probabilistic cellular automaton for a predator-prey system

abstract:
  We consider a probabilistic cellular automaton to analyze the stochastic
dynamics of a predator-prey system. The local rules are Markovian and are based
in the Lotka-Volterra model. The individuals of each species reside on the
sites of a lattice and interact with an unsymmetrical neighborhood. We look for
the effect of the space anisotropy in the characterization of the oscillations
of the species population densities. Our study of the probabilistic cellular
automaton is based on simple and pair mean-field approximations and explicitly
takes into account spatial anisotropy.


title:
Interactions between a massless tensor field with the mixed symmetry of
  the Riemann tensor and a massless vector field

abstract:
  Consistent couplings between a massless tensor field with the mixed symmetry
of the Riemann tensor and a massless vector field are analyzed in the framework
of Lagrangian BRST cohomology. Under the assumptions on smoothness, locality,
Lorentz covariance, and Poincare invariance of the deformations, combined with
the requirement that the interacting Lagrangian is at most second-order
derivative, it is proved that there are no consistent cross-interactions
between a single massless tensor field with the mixed symmetry of the Riemann
tensor and one massless vector field.


title: Controllability of the coupled spin-half harmonic oscillator system

abstract:
  We present a control-theoretic analysis of the system consisting of a
two-level atom coupled with a quantum harmonic oscillator. We show that by
applying external fields with just two resonant frequencies, any desired
unitary operator can be generated.


title:
The log-normal distribution from Non-Gibrat's law in the middle scale
  region of profits

abstract:
  Employing profits data of Japanese firms in 2003--2005, we kinematically
exhibit the static log-normal distribution in the middle scale region. In the
derivation, a Non-Gibrat's law under the detailed balance is adopted together
with following two approximations. Firstly, the probability density function of
profits growth rate is described as a tent-shaped exponential function.
Secondly, the value of the origin of the growth rate distribution divided into
bins is constant. The derivation is confirmed in the database consistently.
  This static procedure is applied to a quasi-static system. We dynamically
describe a quasi-static log-normal distribution in the middle scale region. In
the derivation, a Non-Gibrat's law under the detailed quasi-balance is adopted
together with two approximations confirmed in the static system. The resultant
distribution is power-law with varying Pareto index in the large scale region
and the quasi-static log-normal distribution in the middle scale region. In the
distribution, not only the change of Pareto index but also the change of the
variance of the log-normal distribution depends on the parameter of the
detailed quasi-balance. As a result, Pareto index and the variance of the
log-normal distribution are related to each other.


title:
Cell adhesion and cortex contractility determine cell patterning in the
  Drosophila retina

abstract:
  Hayashi and Carthew (Nature 431 [2004], 647) have shown that the packing of
cone cells in the Drosophila retina resembles soap bubble packing, and that
changing E- and N-cadherin expression can change this packing, as well as cell
shape.
  The analogy with bubbles suggests that cell packing is driven by surface
minimization. We find that this assumption is insufficient to model the
experimentally observed shapes and packing of the cells based on their cadherin
expression. We then consider a model in which adhesion leads to a surface
increase, balanced by cell cortex contraction. Using the experimentally
observed distributions of E- and N-cadherin, we simulate the packing and cell
shapes in the wildtype eye. Furthermore, by changing only the corresponding
parameters, this model can describe the mutants with different numbers of
cells, or changes in cadherin expression.


title: Construction of 3D wormhole supported by phantom energy

abstract:
  In this article, we have found a series solution of 3D Einstein equations
describing a wormhole for an inhomogeneous distribution of phantom energy.
Here, we assume equation of state is linear but highly anistropic.


title: Jet quenching and elliptic flow

abstract:
  In jet quenching, a hard QCD parton, before fragmenting into a jet of
hadrons, deposits a fraction of its energy in the medium, leading to suppressed
production of high-$p_T$ hadrons. Assuming that the deposited energy quickly
thermalizes, we simulate the subsequent hydrodynamic evolution of the QGP
fluid. Explicit simulation of Au+Au collision with and without a quenching jet
indicate that elliptic flow is greatly reduced in a jet event. The result can
be used to identify the jet events in heavy ion collisions.


title: Obtaining the spacetime metric from cosmological observations

abstract:
  Recent galaxy redshift surveys have brought in a large amount of accurate
cosmological data out to redshift 0.3, and future surveys are expected to
achieve a high degree of completeness out to a redshift exceeding 1.
Consequently, a numerical programme for determining the metric of the universe
from observational data will soon become practical; and thereby realise the
ultimate application of Einstein's equations. Apart from detailing the cosmic
geometry, this would allow us to verify and quantify homogeneity, rather than
assuming it, as has been necessary up to now, and to do that on a metric level,
and not merely at the mass distribution level. This paper is the beginning of a
project aimed at such a numerical implementation. The primary observational
data from our past light cone consists of galaxy redshifts, apparent
luminosities, angular diameters and number densities, together with source
evolution functions, absolute luminosities, true diameters and masses of
sources. Here we start with the simplest case, that of spherical symmetry and a
dust equation of state, and execute an algorithm that determines the unknown
metric functions from this data. We discuss the challenges of turning the
theoretical algorithm into a workable numerical procedure, particularly
addressing the origin and the maximum in the area distance. Our numerical
method is tested with several artificial data sets for homogeneous and
inhomogeneous models, successfully reproducing the original models. This
demonstrates the basic viability of such a scheme. Although current surveys
don't have sufficient completeness or accuracy, we expect this situation to
change in the near future, and in the meantime there are many refinements and
generalisations to be added.


title:
Simulation of prompt emission from GRBs with a photospheric component
  and its detectability by GLAST

abstract:
  The prompt emission from gamma-ray bursts (GRBs) still requires a physical
explanation. Studies of time-resolved GRB spectra, observed in the keV-MeV
range, show that a hybrid model consisting of two components, a photospheric
and a non-thermal component, in many cases fits bright, single-pulsed bursts as
well as, and in some instances even better than, the Band function. With an
energy coverage from 8 keV up to 300 GeV, GLAST will give us an unprecedented
opportunity to further investigate the nature of the prompt emission. In
particular, it will give us the possibility to determine whether a photospheric
component is the determining feature of the spectrum or not. Here we present a
short study of the ability of GLAST to detect such a photospheric component in
the sub-MeV range for typical bursts, using simulation tools developed within
the GLAST science collaboration.


title:
Mott-insulating and glassy phases of polaritons in 1D arrays of coupled
  cavities

abstract:
  By means of analytical and numerical methods we analyze the phase diagram of
polaritons in one-dimensional coupled cavities. We locate the phase boundary,
discuss the behavior of the polariton compressibility and visibility fringes
across the critical point, and find a non-trivial scaling of the phase boundary
as a function of the number of atoms inside each cavity. We also predict the
emergence of a polaritonic glassy phase when the number of atoms fluctuates
from cavity to cavity.


title:
Advantages of the multiple scattering representation approach to
  radiation trapping

abstract:
  A simple stochastic formulation of the multiple scattering representation
solution of the classical linear incoherent trapping problem is presented for a
broad audience. A clear connection with the alternative Holstein's solution
ansatz is emphasized by the (re)interpretation of the fundamental mode as the
one associated with a relaxed nonchanging spatial distribution of excitation.
Expressions for overall relaxation parameters (ensemble emission yield and
lifetime) as well as time-resolved (decay and spatial distribution) and
steady-state quantities (spectra and spatial distribution) are given with the
fundamental mode contribution singled out. The multiple scattering
representation is advocated for final undergraduate and beginning graduate
physics instruction based on physical insight and computation feasibility. This
will be illustrated in the following instalment of this contribution.


title: Critical Casimir Effect in superfluid wetting films

abstract:
  Recent experimental data for the complete wetting behavior of pure 4He and of
3He-4He mixtures exposed to solid substrates show that there is a change of the
corresponding film thicknesses L upon approaching thermodynamically the
lambda-transition and the tricritical end point, respectively, which can be
attributed to critical Casimir forces f_C. We calculate the scaling functions
vartheta of f_C within models representing the corresponding universality
classes. For the mixtures our analysis provides an understanding of the rich
behavior of vartheta deduced from the experimental data and predicts the
crossover behavior between the tricritical point and the lambda-transition of
pure 4He which are connected by a line of critical points. The formation of a
'soft-mode' phase within the wetting films gives rise to a pronounced maximum
of f_C below the tricritical point as observed experimentally. Near the
tricritical point we find logarithmic corrections ~L^(-3)(ln L)^(1/2) for the
leading behavior of vartheta dominating the contributions from the background
dispersion forces.


title:
Increase of the mean inner Coulomb potential in Au clusters induced by
  surface tension and its implication for electron scattering

abstract:
  Electron holography in a transmission electron microscope was applied to
measure the phase shift induced by Au clusters as a function of the cluster
size. Large phase shifts Df observed for small Au clusters cannot be described
by the well-known equation Df=C_E V_0 t (C_E: interaction constant, V_0: mean
inner Coulomb potential (MIP) of bulk gold, t: cluster thickness). The rapid
increase of the Au MIP with decreasing cluster size derived from Df, can be
explained by the compressive strain of surface atoms in the cluster.


title: On purely transmitting defects in affine Toda field theory

abstract:
  Affine Toda field theories with a purely transmitting integrable defect are
considered and the model based on a_2 is analysed in detail. After providing a
complete characterization of the problem in a classical framework, a suitable
quantum transmission matrix, able to describe the interaction between an
integrable defect and solitons, is found. Two independent paths are taken to
reach the result. One is an investigation of the triangle equations using the
S-matrix for the imaginary coupling bulk affine Toda field theories proposed by
Hollowood, and the other uses a functional integral approach together with a
bootstrap procedure. Evidence to support the results is collected in various
ways: for instance, through the calculation of the transmission factors for the
lightest breathers. While previous discoveries within the sine-Gordon model
motivated this study, there are several new phenomena displayed in the a_2
model including intriguing disparities between the classical and the quantum
pictures. For example, in the quantum framework, for a specific range of the
coupling constant that excludes a neighbourhood of the classical limit, there
is an unstable bound state.


title: Dirichlet series for finite combinatorial rank dynamics

abstract:
  We introduce a class of group endomorphisms -- those of finite combinatorial
rank -- exhibiting slow orbit growth. An associated Dirichlet series is used to
obtain an exact orbit counting formula, and in the connected case this series
is shown to have a closed rational form. Analytic properties of the Dirichlet
series are related to orbit-growth asymptotics: depending on the location of
the abscissa of convergence and the degree of the pole there, various
orbit-growth asymptotics are found, all of which are polynomially bounded.


title: Symmetry-breaking boundary states for WZW models

abstract:
  Starting with the SU(2)_k WZW model, we construct boundary states that
generically preserve only a parafermion times Virasoro subalgebra of the full
affine Lie algebra symmetry of the bulk model. The boundary states come in
families: intervals for generic k, quotients of SU(2) by discrete groups if k
is a square. In that case, special members of the families can be viewed as
superpositions of rotated Cardy branes. Using embeddings of SU(2) into higher
groups, the new boundary states can be lifted to symmetry-breaking branes for
other WZW models.


title:
Low-temperature and high-temperature approximations for
  penetrable-sphere fluids. Comparison with Monte Carlo simulations and
  integral equation theories

abstract:
  The two-body interaction in dilute solutions of polymer chains in good
solvents can be modeled by means of effective bounded potentials, the simplest
of which being that of penetrable spheres (PSs). In this paper we construct two
simple analytical theories for the structural properties of PS fluids: a
low-temperature (LT) approximation, that can be seen as an extension to PSs of
the well-known solution of the Percus-Yevick (PY) equation for hard spheres,
and a high-temperature (HT) approximation based on the exact asymptotic
behavior in the limit of infinite temperature. Monte Carlo simulations for a
wide range of temperatures and densities are performed to assess the validity
of both theories. It is found that, despite their simplicity, the HT and LT
approximations exhibit a fair agreement with the simulation data within their
respective domains of applicability, so that they complement each other. A
comparison with numerical solutions of the PY and the hypernetted-chain
approximations is also carried out, the latter showing a very good performance,
except inside the core at low temperatures.


title:
Theory of Acoustic Emission for Micro-Cracks Appeared Under the Surface
  Layer Machining by Compressed Abrasive

abstract:
  One of the possible mechanisms for acoustic emission of growing micro-cracks
under conditions of the material machining by com-pressed abrasive has been
theoretically studied. Physical ground of this mechanism is the dislocation
creep in the field of instant contact temperature on stage of micro-cutting
with appearance of the wedge-shaped cavity. It has been shown that the energy
density for radiated acoustic wave at the moment when the cavity is opened
essentially depends on parameters of the material abrasive machining.


title:
Drinfeld second realization of the quantum affine superalgebras of
  $D^{(1)}(2,1;x)$ via the Weyl groupoid

abstract:
  We obtain Drinfeld second realization of the quantum affine superalgebras
associated with the affine Lie superalgebra $D^{(1)}(2,1;x)$. Our results are
analogous to those obtained by Beck for the quantum affine algebras. Beck's
analysis uses heavily the (extended) affine Weyl groups of the affine Lie
algebras. In our approach the structures are based on a Weyl groupoid.


title:
Precise measurements of radio-frequency magnetic susceptibility in
  (anti)ferromagnetic materials

abstract:
  Dynamic magnetic susceptibility, $\chi$, was studied in several intermetallic
materials exhibiting ferromagnetic, antiferromagnetic and metamagnetic
transitions. Precise measurements by using a 14 MHz tunnel diode oscillator
(TDO) allow detailed insight into the field and temperature dependence of
$\chi$. In particular, local moment ferromagnets show a sharp peak in $\chi(T)$
near the Curie temperature, $T_c$. The peak amplitude decreases and shifts to
higher temperatures with very small applied dc fields. Anisotropic measurements
of CeVSb$_3$ show that this peak is present provided the magnetic easy axis is
aligned with the excitation field. In a striking contrast, small moment,
itinerant ferromagnets (i.e., ZrZn$_2$) show a broad maximum in $\chi(T)$ that
responds differently to applied field. We believe that TDO measurements provide
a very sensitive way to distinguish between local and itinerant moment magnetic
orders. Local moment antiferromagnets do not show a peak at the N\'eel
temperature, $T_N$, but only a sharp decrease of $\chi$ below $T_N$ due to the
loss of spin-disorder scattering changing the penetration depth of the ac
excitation field. Furthermore, we show that the TDO is capable of detecting
changes in spin order as well as metamagnetic transitions. Finally, critical
scaling of $\chi(T,H)$ in the vicinity of $T_C$ is discussed in CeVSb$_3$ and
CeAgSb$_2$.


title:
Geometric representation of interval exchange maps over algebraic number
  fields

abstract:
  We consider the restriction of interval exchange transformations to algebraic
number fields, which leads to maps on lattices. We characterize
renormalizability arithmetically, and study its relationships with a
geometrical quantity that we call the drift vector. We exhibit some examples of
renormalizable interval exchange maps with zero and non-zero drift vector, and
carry out some investigations of their properties. In particular, we look for
evidence of the finite decomposition property: each lattice is the union of
finitely many orbits.


title: Comments on the Meta-Stable Vacuum in N_f=N_c SQCD and Direct Mediation

abstract:
  We revisit N_f=N_c SQCD and its non-supersymmetric minima conjectured by
Intriligator, Seiberg and Shih (ISS). We argue that the existence of such
minima depends on the signs of three non-calculable parameters and that no
evidence can be inferred by deforming the theory. We demonstrate this by
studying a deformation of the theory which involves additional gauge singlets.
In this case, the conjectured minimum is destabilized. We comment on the
consequences of such singlets in models of direct mediation and in particular
in the Pentagon model.


title: Diversity Begets Stability in an Evolving Network

abstract:
  Complex evolving systems such as the biosphere, ecosystems and societies
exhibit sudden collapses, for reasons that are only partially understood. Here
we study this phenomenon using a mathematical model of a system that evolves
under Darwinian selection and exhibits the spontaneous growth, stasis and
collapse of its structure. We find that the typical lifetime of the system
increases sharply with the diversity of its components or species. We also find
that the prime reason for crashes is a naturally occurring internal fragility
of the system. This fragility is captured in the network organizational
character and is related to a reduced multiplicity of pathways between its
components. This work suggests new parameters for understanding the robustness
of evolving molecular networks, ecosystems, societies, and markets.


title: Noncommutative tori and the Riemann-Hilbert correspondence

abstract:
  We study the interplay between noncommutative tori and noncommutative
elliptic curves through a category of equivariant differential modules on
$\mathbb{C}^*$. We functorially relate this category to the category of
holomorphic vector bundles on noncommutative tori as introduced by Polishchuk
and Schwarz and study the induced map between the corresponding K-theories. In
addition, there is a forgetful functor to the category of noncommutative
elliptic curves of Soibelman and Vologodsky, as well as a forgetful functor to
the category of vector bundles on $\mathbb{C}^*$ with regular singular
connections.
  The category that we consider has the nice property of being a Tannakian
category, hence it is equivalent to the category of representations of an
affine group scheme. Via an equivariant version of the Riemann-Hilbert
correspondence we determine this group scheme to be (the algebraic hull of)
$\mathbb{Z}^2$. We also obtain a full subcategory of the category of
holomorphic bundles of the noncommutative torus, which is equivalent to the
category of representations of $\mathbb{Z}$. This group is the proposed
topological fundamental group of the noncommutative torus (understood as a
degenerate elliptic curve) and we study Nori's notion of \'etale fundamental
group in this context.


title:
Evolution of Supermassive Black Hole Binary and Acceleration of Jet
  Precession in Galactic Nuclei

abstract:
  Supermassive black hole binary (SMBHB) is expected with the hierarchical
galaxy formation model. Currently, physics processes dominating the evolution
of a SMBHB are unclear. An interesting question is whether we could
observationally determine the evolution of SMBHB and give constraints on the
physical processes. Jet precession have been observed in many AGNs and
generally attributed to disk precession. In this paper we calculate the time
variation of jet precession and conclude that jet precession is accelerated in
SMBHB systems but decelerated in others. The acceleration of jet precession
$dP_{\rm pr} / dt$ is related to jet precession timescale $P_{\rm pr}$ and
SMBHB evolution timescale $\tau_{\rm a}$, ${dP_{\rm pr} \over dt} \simeq -
\Lambda {P_{\rm pr} \over \tau_{\rm a}}$. Our calculations based on the models
for jet precession and SMBHB evolution show that $dP_{\rm pr} / dt$ can be as
high as about $- 1.0$ with a typical value -0.2 and can be easily detected. We
discussed the differential jet precession for NGC1275 observed in the
literature. If the observed rapid acceleration of jet precession is true, the
jet precession is due to the orbital motion of an unbound SMBHB with mass ratio
$q\approx 0.76$. When jets precessed from the ancient bubbles to the currently
active jets, the separation of SMBHB decrease from about $1.46 {\rm Kpc}$ to
$0.80 {\rm Kpc}$ with an averaged decreasing velocity $da/dt \simeq - 1.54
\times 10^6 {\rm cm/s}$ and evolution timescale $\tau_{\rm a} \approx 7.5\times
10^7 {\rm yr}$. However, if we assume a steady jet precession for many cycles,
the observations implies a hard SMBHB with mass ratio $q\approx 0.21$ and
separation $a\approx 0.29 {\rm pc}$.


title:
Monte Carlo simulations reveal the straightening up of an end-grafted
  flexible chain with a rigid side chain

abstract:
  We have studied the conformational properties of a flexible end-grafted chain
(length $N$) with a rigid side chain (length $S$) by means of Monte Carlo
simulations. Depending on the lengths $N$ and $S$ and the branching site, $b$,
we observe a considerable straightening of the flexible backbone as quantified
via the gyration tensor. For $b=N$, i.e. when attaching the side chain to the
free end of the flexible backbone, the effect was strongest.


title: Continuity properties of the integrated density of states on manifolds

abstract:
  We first analyze the integrated density of states (IDS) of periodic
  Schr\"odinger operators on an amenable covering manifold. A criterion for the
continuity of the IDS at a prescribed energy is given along with examples of
operators with both continuous and discontinuous IDS'. Subsequently, alloy-type
perturbations of the periodic operator are considered. The randomness may enter
both via the potential and the metric. A Wegner estimate is proven which
implies the continuity of the corresponding IDS. This gives an example of a
discontinuous "periodic" IDS which is regularized by a random perturbation.


title: Quasi-local energy for cosmological models

abstract:
  First we briefly review our covariant Hamiltonian approach to quasi-local
energy, noting that the Hamiltonian-boundary-term quasi-local energy
expressions depend on the chosen boundary conditions and reference
configuration. Then we present the quasi-local energy values resulting from the
formalism applied to homogeneous Bianchi cosmologies. Finally we consider the
quasi-local energies of the FRW cosmologies. Our results do not agree with
certain widely accepted quasi-local criteria.


title:
Stability Analysis of a Hybrid Cellular Automaton Model of Cell Colony
  Growth

abstract:
  Cell colonies of bacteria, tumour cells and fungi, under nutrient limited
growth conditions, exhibit complex branched growth patterns. In order to
investigate this phenomenon we present a simple hybrid cellular automaton model
of cell colony growth. In the model the growth of the colony is limited by a
nutrient that is consumed by the cells and which inhibits cell division if it
falls below a certain threshold. Using this model we have investigated how the
nutrient consumption rate of the cells affects the growth dynamics of the
colony. We found that for low consumption rates the colony takes on a Eden-like
morphology, while for higher consumption rates the morphology of the colony is
branched with a fractal geometry. These findings are in agreement with previous
results, but the simplicity of the model presented here allows for a linear
stability analysis of the system. By observing that the local growth of the
colony is proportional to the flux of the nutrient we derive an approximate
dispersion relation for the growth of the colony interface. This dispersion
relation shows that the stability of the growth depends on how far the nutrient
penetrates into the colony. For low nutrient consumption rates the penetration
distance is large, which stabilises the growth, while for high consumption
rates the penetration distance is small, which leads to unstable branched
growth. When the penetration distance vanishes the dispersion relation is
reduced to the one describing Laplacian growth without ultra-violet
regularisation. The dispersion relation was verified by measuring how the
average branch width depends on the consumption rate of the cells and shows
good agreement between theory and simulations.


title:
Lattice polytopes having h^*-polynomials with given degree and linear
  coefficient

abstract:
  The h^*-polynomial of a lattice polytope is the numerator of the generating
function of the Ehrhart polynomial. Let P be a lattice polytope with
h^*-polynomial of degree d and with linear coefficient h^*_1. We show that P
has to be a lattice pyramid over a lower-dimensional lattice polytope, if the
dimension of P is greater or equal to h^*_1 (2d+1) + 4d-1. This result has a
purely combinatorial proof and generalizes a recent theorem of Batyrev.


title: Analysis of trembling hand perfect equilibria in quantum games

abstract:
  We analyse Selten's concept of trembling hand perfect equilibria in the
context of quantum game theory. We define trembles as mixed quantum strategies
by replacing discrete probabilities with probability distribution functions.
Explicit examples of analysis are given.


title: A New Model for the Organizational Knowledge Life Cycle

abstract:
  Actual organizations, in particular the ones which operate in evolving and
distributed environments, need advanced frameworks for the management of the
knowledge life cycle. These systems have to be based on the social relations
which constitute the pattern of collaboration ties of the organization. We
demonstrate here, with the aid of a model taken from the theory of graphs, that
it is possible to provide the conditions for an effective knowledge management.
A right way could be to involve the actors with the highest betweeness
centrality in the generation of discussion groups. This solution allows the
externalization of tacit knowledge, the preservation of knowledge and the raise
of innovation processes.


title: Is relaxation correlated in superconducting qubits?

abstract:
  We consider coupled quantum two-state systems (qubits) exposed to a global
relaxation process. The global relaxation refers to the assumption that qubits
are coupled to the same quantum bath with approximately equal strengths,
appropriate for long-wavelength environmental fluctuations. We show that
interactions do not spoil the picture of Dicke's subradiant and superradiant
states where quantum interference effects lead to striking deviations from the
independent relaxation picture. Remarkably, the system possess a stable
entangled state and a state decaying faster than single qubit excitations. We
propose a scheme how these effects can be experimentally accessed in
superconducting flux qubits and, possibly, used in constructing long-lived
entangled states.


title: The hook fusion procedure for Hecke algebras

abstract:
  We derive a new expression for the q-analogue of the Young symmetrizer which
generate irreducible representations of the Hecke algebra. We obtain this new
expression using Cherednik's fusion procedure. However, instead of splitting
Young diagrams into their rows or columns, we consider their principal hooks.
This minimises the number of auxiliary parameters needed in the fusion
procedure.


title: Hydrogen molecule ion: Path integral Monte Carlo approach

abstract:
  Path integral Monte Carlo approach is used to study the coupled quantum
dynamics of the electron and nuclei in hydrogen molecule ion. The coupling
effects are demonstrated by comparing differences in adiabatic
Born--Oppenheimer and non-adiabatic simulations, and inspecting projections of
the full three-body dynamics onto adiabatic Born--Oppenheimer approximation.
  Coupling of electron and nuclear quantum dynamics is clearly seen. Nuclear
pair correlation function is found to broaden by 0.040 a_0 and average bond
length is larger by 0.056 a_0. Also, non-adiabatic correction to the binding
energy is found. Electronic distribution is affected less, and therefore, we
could say that the adiabatic approximation is better for the electron than for
the nuclei.


title: L and T dwarfs in the Hyades and Ursa Major moving groups

abstract:
  We have used the moving cluster method to identify three L dwarfs and one T
dwarf in the Ursa Major/Sirius moving group (age 400 Myr). Five L dwarfs and
two T dwarfs are found to belong to the Hyades moving group (age 625 Myr).
These L and T dwarfs define 400- and 625- Myr empirical isochrones, assuming
that they have the same age. Moving group membership does not guarantee
coevality.


title: Probing Higgs-sector CP Violation at a Photon Collider

abstract:
  In this review we demonstrate physics potential of a photon linear collider
by studying the neutral Higgs-boson sector of the MSSM in which interesting
CP-violating Higgs mixing could arise via radiative corrections.


title:
The structure and energetics of $^3$He and $^4$He nanodroplets doped
  with alkaline earth atoms

abstract:
  We present systematic results, based on density functional calculations, for
the structure and energetics of $^3$He and $^4$He nanodroplets doped with
alkaline earth atoms. We predict that alkaline earth atoms from Mg to Ba go to
the center of $^3$He drops, whereas Ca, Sr, and Ba reside in a deep dimple at
the surface of $^4$He drops, and Mg is at their center. For Ca and Sr, the
structure of the dimples is shown to be very sensitive to the He-alkaline earth
pair potentials used in the calculations. The $5s5p\leftarrow5s^2$ transition
of strontium atoms attached to helium nanodroplets of either isotope has been
probed in absorption experiments. The spectra show that strontium is solvated
inside $^3$He nanodroplets, supporting the calculations. In the light of our
findings, we emphasize the relevance of the heavier alkaline earth atoms for
analyzing mixed $^3$He-$^4$He nanodroplets, and in particular, we suggest their
use to experimentally probe the $^3$He-$^4$He interface.


title: Information feedback and mass media effects in cultural dynamics

abstract:
  We study the effects of different forms of information feedback associated
with mass media on an agent-agent based model of the dynamics of cultural
dissemination. In addition to some processes previously considered, we also
examine a model of local mass media influence in cultural dynamics. Two
mechanisms of information feedback are investigated: (i) direct mass media
influence, where local or global mass media act as an additional element in the
network of interactions of each agent, and (ii) indirect mass media influence,
where global media acts as a filter of the influence of the existing network of
interactions of each agent. Our results generalize previous findings showing
that cultural diversity builds-up by increasing the strength of the mass media
influence. We find that this occurs independently of the mechanisms of action
(direct or indirect) of the mass media message. However, through an analysis of
the full range of parameters measuring cultural diversity, we establish that
the enhancement of cultural diversity produced by interaction with mass media
only occurs for strong enough mass media messages. In comparison with previous
studies a main different result is that weak mass media messages, in
combination with agent-agent interaction, are efficient in producing cultural
homogeneity. Moreover, the homogenizing effect of weak mass media messages are
more efficient for direct local mass media messages than for global mass media
messages or indirect global mass media influences.


title:
The Unruh effect and entanglement generation for accelerated atoms near
  a reflecting boundary

abstract:
  We study, in the framework of open systems, the entanglement generation of
two independent uniformly accelerated atoms in interaction with the vacuum
fluctuations of massless scalar fields subjected to a reflecting plane
boundary. We demonstrate that, with the presence of the boundary, the
accelerated atoms exhibit distinct features from static ones in a thermal bath
at the corresponding Unruh temperature in terms of the entanglement creation at
the neighborhood of the initial time. In this sense, accelerated atoms in
vacuum do not necessarily have to behave as if they were static in a thermal
bath at the Unruh temperature.


title: Stellar Velocity Dispersion of the Leo A Dwarf Galaxy

abstract:
  We measure the first stellar velocity dispersion of the Leo A dwarf galaxy,
\sigma = 9.3 +- 1.3 km/s. We derive the velocity dispersion from the radial
velocities of ten young B supergiants and two HII regions in the central region
of Leo A. We estimate a projected mass of 8 +- 2.7 x10^7 solar masses within a
radius of 2 arcmin, and a mass to light ratio of at least 20 +- 6 M_sun/L_sun.
These results imply Leo A is at least ~80% dark matter by mass.


title: Lorentz Space Estimates for the Ginzburg-Landau Energy

abstract:
  In this paper we prove novel lower bounds for the Ginzburg-Landau energy with
or without magnetic field. These bounds rely on an improvement of the "vortex
balls construction" estimates by extracting a new positive term in the energy
lower bounds. This extra term can be conveniently estimated through a Lorentz
space norm, on which it thus provides an upper bound. The Lorentz space
$L^{2,\infty}$ we use is critical with respect to the expected vortex profiles
and can serve to estimate the total number of vortices and get improved
convergence results.


title:
Monge-Amp\`ere Measures for Convex Bodies and Bernstein-Markov Type
  Inequalities

abstract:
  We use geometric methods to calculate a formula for the complex
Monge-Amp\`ere measure $(dd^cV_K)^n$, for $K \Subset \RR^n \subset \CC^n$ a
convex body and $V_K$ its Siciak-Zaharjuta extremal function. Bedford and
Taylor had computed this for symmetric convex bodies $K$. We apply this to show
that two methods for deriving Bernstein-Markov-type inequalities, i.e.,
pointwise estimates of gradients of polynomials, yield the same results for all
convex bodies. A key role is played by the geometric result that the extremal
inscribed ellipses appearing in approximation theory are the maximal area
ellipses determining the complex Monge-Amp\`ere solution $V_K$.