title: Surmounting collectively oscillating bottlenecks

abstract:
  We study the collective escape dynamics of a chain of coupled, weakly damped
nonlinear oscillators from a metastable state over a barrier when driven by a
thermal heat bath in combination with a weak, globally acting periodic
perturbation. Optimal parameter choices are identified that lead to a drastic
enhancement of escape rates as compared to a pure noise-assisted situation. We
elucidate the speed-up of escape in the driven Langevin dynamics by showing
that the time-periodic external field in combination with the thermal
fluctuations triggers an instability mechanism of the stationary homogeneous
lattice state of the system. Perturbations of the latter provided by incoherent
thermal fluctuations grow because of a parametric resonance, leading to the
formation of spatially localized modes (LMs). Remarkably, the LMs persist in
spite of continuously impacting thermal noise. The average escape time assumes
a distinct minimum by either tuning the coupling strength and/or the driving
frequency. This weak ac-driven assisted escape in turn implies a giant speed of
the activation rate of such thermally driven coupled nonlinear oscillator
chains.


title:
Tunneling spectroscopy of $s\pi$ pairing state as a model for FeAs
  superconductors

abstract:
  We present the self-consistent Bogoliubov-de Gennes calculations of an $s\pi$
pairing state of two band superconductivity as a model for the FeAs
superconductors. The $s\pi$ state is an s-wave pairing state with an internal
$\pi$ phase, that is, nodeless gaps on each band but with the opposite sign.
The novel features of this state are investigated by calculating the local
density of states of the $\pi$ phase superconductor/normal metal bilayers.
Because of the sign reversal between the two condensates, the zero bias
conductance peak appears as observed in tunneling spectroscopy experiments on
FeAs superconductors. This eliminates the major obstacle to establish the
$s\pi$ state as the pairing symmetry of the FeAs superconductors.


title:
Flavour physics and Lattice QCD: averages of lattice inputs for the
  Unitarity Triangle Analysis

abstract:
  We review recent results of Lattice QCD calculations relevant for flavour
physics. We discuss in particular the hadronic parameters entering the
amplitudes of K0-K0bar, D0-D0bar and B0-B0bar mixing, the B- and D-meson decay
constants and the form factors controlling B-meson semileptonic decays. On the
basis of these lattice results, which are extensively collected in the paper,
we also derive our averages of the relevant hadronic parameters.


title:
Reaction Plane Dependent Away-side Modification and Near-side Ridge in
  Au+Au Collisions

abstract:
  STAR preliminary results of di-hadron correlations versus $\phi_{s}$, the
trigger particle azimuthal angle relative to the constructed event plane are
reported for mid-central Au+Au collisions and compared to central Au+Au as well
as minimum bias d+Au collisions. The correlations are observed to vary with
$\phi_{s}$ on both the near and away side of the trigger particle. The
away-side correlation evolves from single- to double-peak with increasing
$\phi_{s}$. The near-side correlation is separated into 'jet' and 'ridge': the
ridge is found to decrease with $\phi_{s}$ while the jet remains relatively
constant.


title: Phase diffusion and locking in single-qubit lasers

abstract:
  Motivated by recent experiments, which demonstrated lasing and cooling of the
electromagnetic field in an electrical resonator coupled to a superconducting
qubit, we study the phase coherence and diffusion of the system in the lasing
state. We also discuss phase locking and synchronization induced by an
additional {\sl ac} driving of the resonator. We extend earlier work to account
for the strong qubit-resonator coupling and to include the effects of
low-frequency qubit's noise. We show that the strong coupling may lead to a
double peak structure of the spectrum, while the shape and width are determined
to the low-frequency noise.


title:
Constraints on CDM cosmology from galaxy power spectrum, CMB and SNIa
  evolution

abstract:
  We examine the constraints that can be obtained on standard cold dark matter
models from the most currently used data set: CMB anisotropies, type Ia
supernovae and the SDSS luminous red galaxies. We also examine how these
constraints are widened when the equation of state parameter $w$ and the
curvature parameter $\Omega_k$ are left as free parameters. For the
$\Lambda$CDM model, our 'vanilla' model, cosmological parameters are tightly
constrained and consistent with current estimates from various methods. When
the dark energy parameter $w$ is free we find that the constraints remain
mostly unchanged, i.e. changes are smaller than the 1 sigma uncertainties.
Similarly, relaxing the assumption of a flat universe leads to nearly identical
constraints on the dark energy density parameter of the universe
$\Omega_\Lambda $, baryon density of the universe $\Omega_b $, the optical
depth $\tau$, the index of the power spectrum of primordial fluctuations $n_S$,
with most one sigma uncertainties better than 5%. More significant changes
appear on other parameters: while preferred values are almost unchanged,
uncertainties for the physical dark matter density $\Omega_ch^2$, Hubble
constant $H_0$ and $\sigma_8$ are typically twice as large. We found that
different methodological approaches on large scale structure estimates lead to
appreciable differences in preferred values and uncertainty widths. We also
found that possible evolution in SNIa intrinsic luminosity does not alter these
constraints by much, except for $w$, for which the uncertainty is twice as
large. At the same time, this possible evolution is severely constrained. We
conclude that systematic uncertainties for some estimated quantities are
similar or larger than statistical ones.


title:
Analisis Kinerja Sistem Cluster Terhadapa Aplikasi Simulasi Dinamika
  Molekular NAMD Memanfaatkan Pustaka CHARM++

abstract:
  Tingkat kompleksitas dari program simulasi dinamika molekular membutuhkan
mesin pemroses dengan kemampuan yang sangat besar. Mesin-mesin paralel terbukti
memiliki potensi untuk menjawab tantangan komputasi ini. Untuk memanfaatkan
potensi ini secara maksimal, diperlukan suatu program paralel dengan tingkat
efisiensi, efektifitas, skalabilitas, dan ekstensibilitas yang maksimal pula.
Program NAMD yang dibahas pada penulisan ini dianggap mampu untuk memenuhi
semua kriteria yang diinginkan. Program ini dirancang dengan
mengimplementasikan pustaka Charm++ untuk pembagian tugas perhitungan secara
paralel. NAMD memiliki sistem automatic load balancing secara periodik yang
cerdas, sehingga dapat memaksimalkan penggunaan kemampuan mesin yang tersedia.
Program ini juga dirancang secara modular, sehingga dapat dimodifikasi dan
ditambah dengan sangat mudah. NAMD menggunakan banyak kombinasi algoritma
perhitungan dan tehnik-tehnik numerik lainnya dalam melakukan tugasnya. NAMD
2.5 mengimplementasikan semua tehnik dan persamaan perhitungan yang digunakan
dalam dunia simulasi dinamika molekular saat ini. NAMD dapat berjalan diatas
berbagai mesin paralel termasuk arsitektur cluster, dengan hasil speedup yang
mengejutkan. Tulisan ini akan menjelaskan dan membuktikan kemampuan NAMD secara
paralel diatas lima buah mesin cluster. Penulisan ini juga akan memaparkan
kinerja NAMD pada beberapa.


title: Crystal structure of the new FeSe1-x superconductor

abstract:
  The newly discovered superconductor FeSe1-x (x=0.08, Tconset=13.5 K at
ambient pressure rising to 27 K at 1.48 GPa) exhibits a structural phase
transition from tetragonal to orthorhombic below 70 K at ambient pressure - the
crystal structure in the superconducting state shows remarkable similarities to
that of the REFeAsO1-xFx (RE = rare earth) superconductors


title: Study of the Science Capabilities of PRIMA in the Galactic Center

abstract:
  The Phase-Referenced Imaging and Micro-arcsecond Astrometry (PRIMA) facility
is scheduled for installation in the Very Large Telescope Interferometer
observatory in Paranal, Chile, in the second half of 2008. Its goal is to
provide astrometric accuracy in the micro-arcsecond range. High precision
astrometry can be applied to explore the dynamics of the dense stellar cluster.
Especially models for the formation of stars near super massive black holes or
the fast transfer of short-lived massive stars into the innermost parsec of our
galaxy can be tested. By measuring the orbits of stars close to the massive
black hole one can probe deviations from a Keplerian motion. Such deviations
could be due to a swarm of dark, stellar mass objects that perturb the point
mass solution. At the same time the orbits are affected by relativistic
corrections which thus can be tested. The ultimate goal is to test the effects
of general relativity in the strong gravitational field. The latter can be
probed with the near infrared flares of SgrA* which are most likely due to
accretion phenomena onto the black hole. We study the expected performance of
PRIMA for astrometric measurements in the Galactic Center based on laboratory
measurements and discuss possible observing strategies.


title: Noise in an SSET-resonator driven by an external field

abstract:
  We investigate the noise properties of a superconducting single electron
transistor (SSET) coupled to an harmonically driven resonator. Using a Langevin
equation approach, we calculate the frequency spectrum of the SSET charge and
calculate its effect on the resonator field. We find that the heights of the
peaks in the frequency spectra depend sensitively on the amplitude of the
resonator oscillation and hence suggest that the heights of these peaks could
act as a sensitive signal for detecting the small changes in the amplitude of
the drive. The previously known results for the effective amplitude-dependent
damping and temperature provided by the SSET for the case of a low frequency
resonator are generalized for all resonator frequencies.


title:
Commensurate Itinerant Antiferromagnetism in BaFe2As2: 75As-NMR Studies
  on a Self-Flux Grown Single Crystal

abstract:
  We report results of 75As nuclear magnetic resonance (NMR) experiments on a
self-flux grown single crystal of BaFe2As2. A first-order antiferromagnetic
(AF) transition near 135 K was detected by the splitting of NMR lines, which is
accompanied by simultaneous structural transition as evidenced by a sudden
large change of the electric field gradient tensor at the As site. The NMR
results lead almost uniquely to the stripe spin structure in the AF phase. The
data of spin-lattice relaxation rate indicate development of anisotropic spin
fluctuations of the stripe-type with decreasing temperature in the paramagnetic
phase.


title:
Moving boundary approximation for curved streamer ionization fronts:
  Solvability analysis

abstract:
  The minimal density model for negative streamer ionization fronts is
investigated. An earlier moving boundary approximation for this model consisted
of a "kinetic undercooling" type boundary condition in a Laplacian growth
problem of Hele-Shaw type. Here we derive a curvature correction to the moving
boundary approximation that resembles surface tension. The calculation is based
on solvability analysis with unconventional features, namely, there are three
relevant zero modes of the adjoint operator, one of them diverging;
furthermore, the inner/outer matching ahead of the front has to be performed on
a line rather than on an extended region; and the whole calculation can be
performed analytically. The analysis reveals a relation between the fields
ahead and behind a slowly evolving curved front, the curvature and the
generated conductivity. This relation forces us to give up the ideal
conductivity approximation, and we suggest to replace it by a constant
conductivity approximation. This implies that the electric potential in the
streamer interior is no longer constant but solves a Laplace equation; this
leads to a Muskat-type problem.


title: Discovery of Hot Gas in Outflow in NGC3379

abstract:
  We report the discovery of a faint (L_x ~ 4 10^37 erg/s, 0.5-2 keV),
out-flowing gaseous hot interstellar medium (ISM) in NGC 3379. This represents
the lowest X-ray luminosity ever measured from a hot phase of the ISM in a
nearby early type galaxy. The discovery of the hot ISM in a very deep Chandra
observation was possible thanks to its unique spectral and spatial signatures,
which distinguish it from the integrated stellar X-ray emission, responsible
for most of the unresolved emission in the Chandra data. This hot component is
found in a region of about 800 pc in radius at the center of the galaxy and has
a total mass M~ 3 10^5 solar masses. Independent theoretical prediction of the
characteristics of an ISM in this galaxy, based on the intrinsic properti es of
NGC 3379, reproduce well the observed luminosity, temperature, and radial
distribution and mass of the hot gas, and indicate that the gas is in an
outflowing phase, predicted by models but not observed in any system so far.


title:
Bound state formation and nature of the excitonic insulator phase in the
  extended Falicov-Kimball model

abstract:
  Motivated by the possibility of pressure-induced exciton condensation in
intermediate-valence Tm[Se,Te] compounds we study the Falicov-Kimball model
extended by a finite f-hole valence bandwidth. Calculating the Frenkel-type
exciton propagator we obtain excitonic bound states above a characteristic
value of the local interband Coulomb attraction. Depending on the system
parameters coherence between c- and f-states may be established at low
temperatures, leading to an excitonic insulator phase. We find strong evidence
that the excitonic insulator typifies either a BCS condensate of electron-hole
pairs (weak-coupling regime) or a Bose-Einstein condensate (BEC) of preformed
excitons (strong-coupling regime), which points towards a BCS-BEC transition
scenario as Coulomb correlations increase.


title:
High-temperature expansion of the magnetic susceptibility and higher
  moments of the correlation function for the two-dimensional XY model

abstract:
  We calculate the high-temperature series of the magnetic susceptibility and
the second and fourth moments of the correlation function for the XY model on
the square lattice to order $\beta^{33}$ by applying the improved algorithm of
the finite lattice method. The long series allow us to estimate the inverse
critical temperature as $\beta_c=1.1200(1)$, which is consistent with the most
precise value given previously by the Monte Carlo simulation. The critical
exponent for the multiplicative logarithmic correction is evaluated to be
$\theta=0.054(10)$, which is consistent with the renormalization group
prediction of $\theta={1/16}$.


title: AceWiki: A Natural and Expressive Semantic Wiki

abstract:
  We present AceWiki, a prototype of a new kind of semantic wiki using the
controlled natural language Attempto Controlled English (ACE) for representing
its content. ACE is a subset of English with a restricted grammar and a formal
semantics. The use of ACE has two important advantages over existing semantic
wikis. First, we can improve the usability and achieve a shallow learning
curve. Second, ACE is more expressive than the formal languages of existing
semantic wikis. Our evaluation shows that people who are not familiar with the
formal foundations of the Semantic Web are able to deal with AceWiki after a
very short learning phase and without the help of an expert.


title:
Guaranteed Cost LQG Control of Uncertain Linear Quantum Stochastic
  Systems

abstract:
  In this paper, we formulate and solve a guaranteed cost control problem for a
class of uncertain linear stochastic quantum systems. For these quantum
systems, a connection with an associated classical (non-quantum) system is
first established. Using this connection, the desired guaranteed cost results
are established. The theory presented is illustrated using an example from
quantum optics.


title:
A Compositional Query Algebra for Second-Order Logic and Uncertain
  Databases

abstract:
  World-set algebra is a variable-free query language for uncertain databases.
It constitutes the core of the query language implemented in MayBMS, an
uncertain database system. This paper shows that world-set algebra captures
exactly second-order logic over finite structures, or equivalently, the
polynomial hierarchy. The proofs also imply that world-set algebra is closed
under composition, a previously open problem.


title: On the $M_t/M_t/K_t+M_t$ queue in heavy traffic

abstract:
  The focus of this paper is on the asymptotics of large-time numbers of
customers in time-periodic Markovian many-server queues with customer
abandonment in heavy traffic. Limit theorems are obtained for the periodic
number-of-customers processes under the fluid and diffusion scalings. Other
results concern limits for general time-dependent queues and for
time-homogeneous queues in steady state.


title:
delta Cen: a new binary Be star detected by VLTI/AMBER
  spectro-interferometry

abstract:
  We study the Be star $\delta$ Cen circumstellar disk using long-baseline
interferometry which is the only observing technique capable of resolving
spatially and spectroscopically objects smaller than 5 mas in the H and K b
and. We used the VLTI/AMBER instrument on January 6, 8, and 9, 2008, in the H
and K bands to complete low (35) and medium (150 0) spectral resolution
observations. We detected an oscillation in the visibility curve plotted as a
function of the spatial frequency which is a clear signat ure of a companion
around $\delta$ Cen. Our best-fit soltution infers a binary separation of 68.7
mas, a companion flux co ntribution in the K band of about 7% of the total
flux, a PA of 117.5 $\degr$, and an envelope flux around the Be primary that
contributes up to about 50 % of the total flux, in agreement with our Spectral
Energy Distribution (SED) fit. The e nvelope size is estimated to be 1.6 mas in
K but no departure from spherical symmetry is detected.


title:
AceWiki: Collaborative Ontology Management in Controlled Natural
  Language

abstract:
  AceWiki is a prototype that shows how a semantic wiki using controlled
natural language - Attempto Controlled English (ACE) in our case - can make
ontology management easy for everybody. Sentences in ACE can automatically be
translated into first-order logic, OWL, or SWRL. AceWiki integrates the OWL
reasoner Pellet and ensures that the ontology is always consistent. Previous
results have shown that people with no background in logic are able to add
formal knowledge to AceWiki without being instructed or trained in advance.


title:
Comment to the paper D. V. Anchishkin and S. N. Yezhov "Thermalization
  in Heavy-ion Collisions"

abstract:
  Here I discuss the major pitfalls and the most severe mistakes of the above
mentioned paper. The thorough analysis shows that despite all the claims the
present work has nothing to do with the thermalization process in relativistic
heavy ion collisions. In contrast to the authors' beliefs I show that their
main result is not derived, but is a combination of mathematical mistakes and
hand waving arguments.


title: Soft supersymmetry breaking terms from A4 lepton flavor symmetry

abstract:
  We study the supersymmetric model with the A4 lepton flavor symmetry, in
particular soft supersymmetry breaking terms, which are predicted from the A4
lepton flavor symmetry. We evaluate soft slepton masses and A-terms within the
framework of supergravity theory. Constraints due to experiments of flavor
changing neutral current processes are examined.


title: Approximate kernel clustering

abstract:
  In the kernel clustering problem we are given a large $n\times n$ positive
semi-definite matrix $A=(a_{ij})$ with $\sum_{i,j=1}^na_{ij}=0$ and a small
$k\times k$ positive semi-definite matrix $B=(b_{ij})$. The goal is to find a
partition $S_1,...,S_k$ of $\{1,... n\}$ which maximizes the quantity $$
\sum_{i,j=1}^k (\sum_{(i,j)\in S_i\times S_j}a_{ij})b_{ij}. $$ We study the
computational complexity of this generic clustering problem which originates in
the theory of machine learning. We design a constant factor polynomial time
approximation algorithm for this problem, answering a question posed by Song,
Smola, Gretton and Borgwardt. In some cases we manage to compute the sharp
approximation threshold for this problem assuming the Unique Games Conjecture
(UGC). In particular, when $B$ is the $3\times 3$ identity matrix the UGC
hardness threshold of this problem is exactly $\frac{16\pi}{27}$. We present
and study a geometric conjecture of independent interest which we show would
imply that the UGC threshold when $B$ is the $k\times k$ identity matrix is
$\frac{8\pi}{9}(1-\frac{1}{k})$ for every $k\ge 3$.


title: The absence of fragmentation in Bose-Einstein condensates

abstract:
  A Bose-Einstein condensate produced by a Hamiltonian which is rotationally or
translationally symmetric is fragmented as a direct result of these symmetries.
A corresponding mean-field unfragmented state, with an identical energy to
leading order in the number of particles, can generally be constructed. As a
consequence, vanishingly weak symmetry-breaking perturbations destabilize the
fragmented state, which would thus be extremely difficult to realize
experimentally, and lead to an unfragmented condensate.


title: Scaling Analysis of the Site-Diluted Ising Model in Two Dimensions

abstract:
  A combination of recent numerical and theoretical advances are applied to
analyze the scaling behaviour of the site-diluted Ising model in two
dimensions, paying special attention to the implications for multiplicative
logarithmic corrections. The analysis focuses primarily on the odd sector of
the model (i.e., that associated with magnetic exponents), and in particular on
its Lee-Yang zeros, which are determined to high accuracy. Scaling relations
are used to connect to the even (thermal) sector, and a first analysis of the
density of zeros yields information on the specific heat and its corrections.
The analysis is fully supportive of the strong scaling hypothesis and of the
scaling relations for logarithmic corrections.


title:
Comment on 'Transient response of a wetting film to mechanical and
  electrical perturbations'

abstract:
  A comment on the recent paper of R Manica, J N Connor, L Y Clasohm, S L
Carnie, R G Horn, D Y C Chan, Transient response of a wetting film to
mechanical and electrical perturbations, Langmuir 2008, 24, 1381.


title: Counting perfect colourings of plane regular tilings

abstract:
  A first step in investigating colour symmetries of periodic and nonperiodic
patterns is determining the number of colours which allow perfect colourings of
the pattern under consideration. A perfect colouring is one where each symmetry
of the uncoloured pattern induces a global permutation of the colours. Two
cases are distinguished: Either perfect colourings with respect to all
symmetries, or with respect to orientation preserving symmetries only (no
reflections). For the important class of colourings of regular tilings (and
some Laves tilings) of the Euclidean or hyperbolic plane, this mainly
combinatorial question is addressed here using group theoretical methods.


title: Magnetic Landscape of Sun's Polar Region

abstract:
  We present the magnetic landscape of the polar region of the Sun that is
unprecedented in terms of high spatial resolution, large field of view, and
polarimetric precision. These observations were carried out with the Solar
Optical Telescope aboard \emph{Hinode}. Using a Milne-Eddington inversion, we
found many vertically-oriented magnetic flux tubes with field strength as
strong as 1 kG that are scattered in latitude between 70-90 degree. They all
have the same polarity, consistent with the global polarity of the polar
region. The field vectors were observed to diverge from the center of the flux
elements, consistent with a view of magnetic fields that expand and fan out
with height. The polar region is also covered with ubiquitous horizontal
fields. The polar regions are the source of the fast solar wind channelled
along unipolar coronal magnetic fields whose photospheric source is evidently
rooted in the strong field, vertical patches of flux. We conjecture that
vertical flux tubes with large expansion around the photosphere-corona boundary
serve as efficient chimneys for Alfven waves that accelerate the solar wind.


title: Quantum Thermodynamics of Non-Ideal Gases

abstract:
  We show that when the thermal wavelength is comparable to the spatial size of
a system, thermodynamic observables like Pressure and Volume have quantum
fluctuations that cannot be ignored. They are now represented by operators;
conventional (classical) thermodynamics is no longer applicable. We continue
the work in earlier papers where quantization rules for thermodynamics were
developed by analogy with optics and mechanics, by working out explicitly the
quantum theory of van der Waals gases. We find a wave equation satisfied by the
thermodynamic wave function as well as solutions ({\em coherent states}) that
are centered at the classical equations of state. The probability of departure
from the classical theory is dependent on a parameter $\sigma$ which is a
property of the gas molecule.

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


title: Hubbard Model with Inter-Site Kinetic Correlations

abstract:
  We introduced the inter-site electron-electron correlation to the Hubbard III
approximation. This correlation was excluded in the Hubbard III approximation
and also in the equivalent coherent potential approximation. Including it
brings two spin dependent effects: the bandwidth correction and the bandshift
correction, which both stimulate the ferromagnetic ground state. The bandshift
correction factor causes an exchange splitting between the spin-up and
spin-down spectrum, and its role is similar to the exchange interaction in the
classic Stoner model. The spin dependent bandwidth correction lowers the
kinetic energy of electrons by decreasing the majority spin bandwidth for some
electron occupations with respect to the minority spin bandwidth. In certain
conditions it can lead to ferromagnetic alignment. A gain in the kinetic energy
achieved in this way is the opposite extreme to the effect of a gain in
potential energy due to exchange splitting. The bandshift factor is a dominant
force behind the ferromagnetism. The influence of the bandwidth factor is too
weak to create ferromagnetism and the only result is the correction to the
classic coherent potential approximation in favor of ferromagnetism.


title: The search for Population III stars

abstract:
  Population III stars, the first generation of stars formed from primordial
Big Bang material with a top-heavy IMF, should contribute substantially to the
Universe reionization and they are crucial for understanding the early metal
enrichment of galaxies. Therefore it is very important that these objects,
foreseen by theories, are detected by observations. However PopIII stars,
searched through the HeII 1640A line signature, have remained elusive. We
report about the search for the HeII line in a galaxy at z=6.5, which is a very
promising candidate. Unfortunately we are not yet able to show the results of
this search. However we call attention to the possible detection of PopIII
stars in a lensed HII dwarf galaxy at z=3.4, which appeared in the literature
some years ago, but has been overlooked.


title: Coulomb gauge Yang-Mills theory in the Hamiltonian approach

abstract:
  Within the Hamiltonian approach in Coulomb gauge the ghost and gluon
propagators are determined from a variational solution of the Yang-Mills
Schroedinger equation showing both gluon and heavy quark confinement. The
continuum results are in good agreement with lattice data. The ghost form
factor is identified as the dielectric function of the Yang-Mills vacuum and a
connection between the Gribov-Zwanziger scenario and the dual Meissner effect
is established. The topological susceptibility is calculated.


title:
The VVDS-SWIRE-GALEX-CFHTLS surveys: Physical properties of galaxies at
  z below 1.2 from photometric data

abstract:
  We intend to show that it is possible to derive the physical parameters of
galaxies from their broad-band spectral energy distribution out to a redshift
of 1.2. This method has the potential to yield the physical parameters of all
galaxies in a single field in a homogeneous way. We use an extensive dataset,
assembled in the context of the VVDS survey, which reaches from the UV to the
IR and covers a sample of 84073 galaxies over an area of 0.89 deg$^2$. We also
use a library of 100000 model galaxies with a large variety of star formation
histories (in particular including late bursts of star formation). We find that
we can determine the physical parameters stellar mass, age and star formation
rate with good confidence. We validate the star formation rate determinations
in particular by comparing it to a sample of spectroscopically observed
galaxies with an emission line measurement. We use our sample to build the
number density function of galaxies as a function of stellar mass, specific
star formation rate and redshift. We then study whether the stellar mass
function at a later time can be predicted from the stellar mass function and
star formation rate distribution at an earlier time. We find that the predicted
growth in stellar mass from star formation agrees with the observed one.
However, the predicted stellar mass density for massive galaxies is lower than
observed, while the mass density of intermediate mass galaxies is
overpredicted. When comparing with a direct measurement of the major merger
rate from the VVDS survey we find that major mergers are sufficient to explain
about a third of the mass build-up at the massive end, while the rest is likely
contributed through minor mergers.


title: Covariant Anomalies, Horizons and Hawking Radiation

abstract:
  Hawking radiation is obtained from anomalies resulting from a breaking of
diffeomorphism symmetry near the event horizon of a black hole. Such anomalies,
manifested as a nonconservation of the energy momentum tensor, occur in two
different forms -- covariant and consistent. The crucial role of covariant
anomalies near the horizon is revealed since this is the {\it only} input
required to obtain the Hawking flux, thereby highlighting the universality of
this effect. A brief description to apply this method to obtain thermodynamic
entities like entropy or temperature is provided.


title: The nature of NV absorbers at high redshift

abstract:
  We present a study of NV absorption systems at 1.5 < z < 2.5 in the optical
spectra of 19 QSOs. Our analysis includes both absorbers arising from the
intergalactic medium as well as systems in the vicinity of the background
quasar. We construct detailed photoionization models to study the physical
conditions and abundances in the absorbers and to constrain the spectral
hardness of the ionizing radiation. The rate of incidence for intervening NV
components is dN/dz = 3.38 +/- 0.43, corresponding to dN/dX = 1.10 +/- 0.14.
The column density distribution function is fitted by the slope beta = 1.89 +/-
0.22, consistent with measurements for CIV and OVI. The narrow line widths
(b_NV ~ 6 km/s) imply photoionization rather than collisions as dominating
ionization process. The column densities of CIV and NV are correlated but show
different slopes for intervening and associated absorbers, which indicates
different ionizing spectra. Associated systems are found to be more metal-rich,
denser, and more compact than intervening absorbers. This conclusion is
independent of the adopted ionizing radiation. For the intervening NV systems
we find typical values of [C/H] ~ -0.6 and n_H ~ 10^-3.6 cm^-3, and sizes of a
few kpc, while for associated NV absorbers we obtain [C/H] ~ +0.7, n_H ~
10^-2.8 cm^-3, and sizes of several 10 pc. The abundance of nitrogen relative
to carbon [N/C] and alpha-elements like oxygen and silicon [N/alpha] is
correlated with [N/H], indicating the enrichment by secondary nitrogen. The
larger scatter in [N/alpha] in intervening systems suggests an inhomogeneous
enrichment of the IGM. There is an anti-correlation between [N/alpha] and
[alpha/C], which could be used to constrain the initial mass function of the
carbon- and nitrogen-producing stellar population.


title:
Emergence of long memory in stock volatility from a modified Mike-Farmer
  model

abstract:
  The Mike-Farmer (MF) model was constructed empirically based on the
continuous double auction mechanism in an order-driven market, which can
successfully reproduce the cubic law of returns and the diffusive behavior of
stock prices at the transaction level. However, the volatility (defined by
absolute return) in the MF model does not show sound long memory. We propose a
modified version of the MF model by including a new ingredient, that is, long
memory in the aggressiveness (quantified by the relative prices) of incoming
orders, which is an important stylized fact identified by analyzing the order
flows of 23 liquid Chinese stocks. Long memory emerges in the volatility
synthesized from the modified MF model with the DFA scaling exponent close to
0.76, and the cubic law of returns and the diffusive behavior of prices are
also produced at the same time. We also find that the long memory of order
signs has no impact on the long memory property of volatility, and the memory
effect of order aggressiveness has little impact on the diffusiveness of stock
prices.


title:
Hyperbolic conservation laws on manifolds. Error estimate for finite
  volume schemes

abstract:
  Following Ben-Artzi and LeFloch, we consider nonlinear hyperbolic
conservation laws posed on a Riemannian manifold, and we establish an L1-error
estimate for a class of finite volume schemes allowing for the approximation of
entropy solutions to the initial value problem. The error in the L1 norm is of
order h^(1/4) at most, where h represents the maximal diameter of elements in
the family of geodesic triangulations. The proof relies on a suitable
generalization of Cockburn, Coquel, and LeFloch's theory which was originally
developed in the Euclidian setting. We extent the arguments to curved
manifolds, by taking into account the effects to the geometry and overcoming
several new technical difficulties.


title:
Resonance fluorescence in driven quantum dots: electron and photon
  correlations

abstract:
  We study the counting statistics for electrons and photons being emitted from
a driven two level quantum dot. Our technique allows us to calculate their
mutual correlations as well. We study different transport configurations by
tuning the chemical potential of one of the leads to find that the electronic
and photonic fluctuations can be externally manipulated by tuning the AC and
transport parameters. We also propose special configurations where
electron-photon correlation is maximal meaning that spontaneous emission of
photons with a well defined energy is regulated by single electron tunneling.
Interesting features are also obtained for energy dependent tunneling.


title: An MCMC Fitting Method for Triaxial Dark Matter Haloes

abstract:
  Measuring the 3D distribution of mass on galaxy cluster scales is a crucial
test of the LCDM model, providing constraints on the behaviour of dark matter.
Recent work investigating mass distributions of individual galaxy clusters
(e.g. Abell 1689) using weak and strong gravitational lensing has revealed
potential inconsistencies between the predictions of structure formation models
relating halo mass to concentration and those relationships as measured in
massive clusters. However, such analyses employ simple spherical halo models
while a growing body of work indicates that triaxial 3D halo structure is both
common and important in parameter estimates. The very strong assumptions about
the symmetry of the lensing halo implied with circular or perturbative
elliptical NFW models are not physically motivated and lead to incorrect
parameter estimates with significantly underestimated error bars. We here
introduce a Markov Chain Monte Carlo (MCMC) method to fit fully triaxial models
to weak lensing data that gives parameter and error estimates that fully
incorporate the true uncertainty present in nature. Applying the MCMC triaxial
fitting method to a population of NFW triaxial lenses drawn from the shape
distribution of structure formation simulations, we find that including
triaxiality cannot explain a population of massive, highly concentrated
clusters within the framework of LCDM, but easily explains rare cases of
apparently massive, highly concentrated, very efficient lensing clusters. Our
MCMC triaxial NFW fitting method is easily expandable to include constraints
from additional data types, and its application returns model parameters and
errors that more accurately capture the true (and limited) extent of our
knowledge of the structure of galaxy cluster lenses. (abridged)


title: Vortex jamming in superconductors and granular rheology

abstract:
  We demonstrate that a highly frustrated anisotropic Josephson junction
array(JJA) on a square lattice exhibits a zero-temperature jamming transition,
which shares much in common with those in granular systems. Anisotropy of the
Josephson couplings along the horizontal and vertical directions plays roles
similar to normal load or density in granular systems. We studied numerically
static and dynamic response of the system against shear, i. e. injection of
external electric current at zero temperature. Current-voltage curves at
various strength of the anisotropy exhibit universal scaling features around
the jamming point much as do the flow curves in granular rheology, shear-stress
vs shear-rate. It turns out that at zero temperature the jamming transition
occurs right at the isotropic coupling and anisotropic JJA behaves as an exotic
fragile vortex matter : it behaves as superconductor (vortex glass) into one
direction while normal conductor (vortex liquid) into the other direction even
at zero temperature. Furthermore we find a variant of the theoretical model for
the anisotropic JJA quantitatively reproduces universal master flow-curves of
the granular systems. Our results suggest an unexpected common paradigm
stretching over seemingly unrelated fields - the rheology of soft materials and
superconductivity.


title: Optimal potentials for temperature ratchets

abstract:
  In a spatially periodic temperature profile, directed transport of an
overdamped Brownian particle can be induced along a periodic potential. With a
load force applied to the particle, this setup can perform as a heat engine.
For a given load, the optimal potential maximizes the current and thus the
power output of the heat engine. We calculate the optimal potential for
different temperature profiles and show that in the limit of a periodic
piecewise constant temperature profile alternating between two temperatures,
the optimal potential leads to a divergent current. This divergence, being an
effect of both the overdamped limit and the infinite temperature gradient at
the interface, would be cut off in any real experiment.


title:
Kinetics of the initial stage of immunoagglutionation studied with the
  scanning flow cytometer

abstract:
  The use of a scanning flow cytometer (SFC) to study the evolution of
monomers, dimers and higher multimers of latex particles at the initial stage
of the immunoagglutination is described. The SFC can measure the
light-scattering pattern (indicatrix) of an individual particle over an angular
range of 10-60 deg. A comparison of the experimentally measured and
theoretically calculated indicatrices allows one to discriminate different
types of latex particles (i.e. monomers, dimers, etc.) and, therefore, to study
the evolution of immunoagglutination process. Validity of the approach was
verified by simultaneous measurements of light-scattering patterns and
fluorescence from individual polymer particles. Immunoagglutination was
initiated by mixing bovine serum albumin (BSA)-covered latex particles (of 1.8
um in diameter) with anti-BSA IgG. The analysis of experimental data was
performed on the basis of a mathematical model of diffusion-limited
immunoagglutination aggregation with a steric factor. The steric factor was
determined by the size and the number of binding sites on the surface of a
latex particle. The obtained data are in good agreement with the proposed
mathematical modeling.


title: On the algebra of quantum observables for a certain gauge model

abstract:
  We prove that the algebra of observables of a certain gauge model is
generated by unbounded elements in the sense of Woronowicz. The generators are
constructed from the classical generators of invariant polynomials by means of
geometric quantization.


title:
Defect Energy Levels in Density Functional Calculations: Alignment and
  Band Gap Problem

abstract:
  For materials of varying band gap, we compare energy levels of atomically
localized defects calculated within a semilocal and a hybrid density-functional
scheme. Since the latter scheme partially relieves the band gap problem, our
study describes how calculated defect levels shift when the band gap approaches
the experimental value. When suitably aligned, defect levels obtained from
total-energy differences correspond closely, showing average shifts of at most
0.2 eV irrespective of band gap. Systematic deviations from ideal alignment
increase with the extent of the defect wave function. A guideline for comparing
calculated and experimental defect levels is provided.


title:
Impalement transitions in droplets impacting microstructured
  superhydrophobic surfaces

abstract:
  Liquid droplets impacting a superhydrophobic surface decorated with
micro-scale posts often bounce off the surface. However, by decreasing the
impact velocity droplets may land on the surface in a fakir state, and by
increasing it posts may impale droplets that are then stuck on the surface. We
use a two-phase lattice-Boltzmann model to simulate droplet impact on
superhydrophobic surfaces, and show that it may result in a fakir state also
for reasonable high impact velocities. This happens more easily if the surface
is made more hydrophobic or the post height is increased, thereby making the
impaled state energetically less favourable.


title:
Hidden Markov models for the assessment of chromosomal alterations using
  high-throughput SNP arrays

abstract:
  Chromosomal DNA is characterized by variation between individuals at the
level of entire chromosomes (e.g., aneuploidy in which the chromosome copy
number is altered), segmental changes (including insertions, deletions,
inversions, and translocations), and changes to small genomic regions
(including single nucleotide polymorphisms). A variety of alterations that
occur in chromosomal DNA, many of which can be detected using high density
single nucleotide polymorphism (SNP) microarrays, are linked to normal
variation as well as disease and are therefore of particular interest. These
include changes in copy number (deletions and duplications) and genotype (e.g.,
the occurrence of regions of homozygosity). Hidden Markov models (HMM) are
particularly useful for detecting such alterations, modeling the spatial
dependence between neighboring SNPs. Here, we improve previous approaches that
utilize HMM frameworks for inference in high throughput SNP arrays by
integrating copy number, genotype calls, and the corresponding measures of
uncertainty when available. Using simulated and experimental data, we, in
particular, demonstrate how confidence scores control smoothing in a
probabilistic framework. Software for fitting HMMs to SNP array data is
available in the R package VanillaICE.


title:
Point Canonical Transformation versus Deformed Shape Invariance for
  Position-Dependent Mass Schr\"odinger Equations

abstract:
  On using the known equivalence between the presence of a position-dependent
mass (PDM) in the Schr\"odinger equation and a deformation of the canonical
commutation relations, a method based on deformed shape invariance has recently
been devised for generating pairs of potential and PDM for which the
Schr\"odinger equation is exactly solvable. This approach has provided the
bound-state energy spectrum, as well as the ground-state and the first few
excited-state wavefunctions. The general wavefunctions have however remained
unknown in explicit form because for their determination one would need the
solutions of a rather tricky differential-difference equation. Here we show
that solving this equation may be avoided by combining the deformed shape
invariance technique with the point canonical transformation method in a novel
way. It consists in employing our previous knowledge of the PDM problem energy
spectrum to construct a constant-mass Schr\"odinger equation with similar
characteristics and in deducing the PDM wavefunctions from the known
constant-mass ones. Finally, the equivalence of the wavefunctions coming from
both approaches is checked.


title: Effect of magnesium doping on the orbital and magnetic order in LiNiO2

abstract:
  In LiNiO2, the Ni3+ ions, with S=1/2 and twofold orbital degeneracy, are
arranged on a trian- gular lattice. Using muon spin relaxation (MuSR) and
electron spin resonance (ESR), we show that magnesium doping does not stabilize
any magnetic or orbital order, despite the absence of interplane Ni2+. A
disordered, slowly fluctuating state develops below 12 K. In addition, we find
that magnons are excited on the time scale of the ESR experiment. At the same
time, a g factor anisotropy is observed, in agreement with $| 3z^{2}-r^{2}>$
orbital occupancy.


title:
Measurement of the top quark mass with dilepton events selected using
  neuroevolution at CDF

abstract:
  We report a measurement of the top quark mass $M_t$ in the dilepton decay
channel $t\bar{t}\to b\ell'^{+}\nu'_\ell\bar{b}\ell^{-}\bar{\nu}_{\ell}$.
Events are selected with a neural network which has been directly optimized for
statistical precision in top quark mass using neuroevolution, a technique
modeled on biological evolution. The top quark mass is extracted from per-event
probability densities that are formed by the convolution of leading order
matrix elements and detector resolution functions. The joint probability is the
product of the probability densities from 344 candidate events in 2.0 fb$^{-1}$
of $p\bar{p}$ collisions collected with the CDF II detector, yielding a
measurement of $M_t= 171.2\pm 2.7(\textrm{stat.})\pm
2.9(\textrm{syst.})\mathrm{GeV}/c^2$.


abstract:
  We give an overview of ISINA: INTEGRAL Source Identification Network
Algorithm. This machine learning algorithm, using Random Forests, is applied to
the IBIS/ISGRI dataset in order to ease the production of unbiased future soft
gamma-ray source catalogues. First we introduce the dataset and the problems
encountered when dealing with images obtained using the coded mask technique.
The initial step of source candidate searching is introduced and an initial
candidate list is created. A description of the feature extraction on the
initial candidate list is then performed together with feature merging for
these candidates. Three training and testing sets are created in order to deal
with the diverse timescales encountered when dealing with the gamma-ray sky.
Three independent Random Forest are built: one dealing with faint persistent
source recognition, one dealing with strong persistent sources and a final one
dealing with transients. For the latter, a new transient detection technique is
introduced and described: the Transient Matrix. Finally the performance of the
network is assessed and discussed using the testing set and some illustrative
source examples.


title: Round about Theta. Part I Prehistory

abstract:
  There is a huge amount of work on different kinds of theta functions, the
theta correspondence, cohomology classes coming from special Schwartz classes
via theta distribution, and much more. The aim of this text is to try to find
joint construction principles while often leaving aside relevant but cumbersome
details.


title: Candy-passing Games on General Graphs, II

abstract:
  We give a new proof that any candy-passing game on a graph G with at least
4|E(G)|-|V(G)| candies stabilizes. (This result was first proven in
arXiv:0807.4450.) Unlike the prior literature on candy-passing games, we use
methods from the general theory of chip-firing games which allow us to obtain a
polynomial bound on the number of rounds before stabilization.


title:
Energy-delay bounds analysis in wireless multi-hop networks with
  unreliable radio links

abstract:
  Energy efficiency and transmission delay are very important parameters for
wireless multi-hop networks. Previous works that study energy efficiency and
delay are based on the assumption of reliable links. However, the unreliability
of the channel is inevitable in wireless multi-hop networks. This paper
investigates the trade-off between the energy consumption and the end-to-end
delay of multi-hop communications in a wireless network using an unreliable
link model. It provides a closed form expression of the lower bound on the
energy-delay trade-off for different channel models (AWGN, Raleigh flat fading
and Nakagami block-fading) in a linear network. These analytical results are
also verified in 2-dimensional Poisson networks using simulations. The main
contribution of this work is the use of a probabilistic link model to define
the energy efficiency of the system and capture the energy-delay trade-offs.
Hence, it provides a more realistic lower bound on both the energy efficiency
and the energy-delay trade-off since it does not restrict the study to the set
of perfect links as proposed in earlier works.


title:
Non-diffusive large time behaviour for a degenerate viscous
  Hamilton-Jacobi equation

abstract:
  The convergence to non-diffusive self-similar solutions is investigated for
non-negative solutions to the Cauchy problem $\partial_t u = \Delta_p u +
|\nabla u|^q$ when the initial data converge to zero at infinity. Sufficient
conditions on the exponents $p>2$ and $q>1$ are given that guarantee that the
diffusion becomes negligible for large times and the $L^\infty$-norm of $u(t)$
converges to a positive value as $t\to\infty$.


title:
Unsupervised empirical Bayesian multiple testing with external
  covariates

abstract:
  In an empirical Bayesian setting, we provide a new multiple testing method,
useful when an additional covariate is available, that influences the
probability of each null hypothesis being true. We measure the posterior
significance of each test conditionally on the covariate and the data, leading
to greater power. Using covariate-based prior information in an unsupervised
fashion, we produce a list of significant hypotheses which differs in length
and order from the list obtained by methods not taking covariate-information
into account. Covariate-modulated posterior probabilities of each null
hypothesis are estimated using a fast approximate algorithm. The new method is
applied to expression quantitative trait loci (eQTL) data.


title: Path integral derivations of novel complex trajectory methods

abstract:
  Path integral derivations are presented for two recently developed complex
trajectory techniques for the propagation of wave packets, Complex WKB and
BOMCA. Complex WKB is derived using a standard saddle point approximation of
the path integral, but taking into account the hbar dependence of both the
amplitude and the phase of the intial wave function, thus giving rise to the
need for complex classical trajectories. BOMCA is derived using a modification
of the saddle point technique, in which the path integral is approximated by
expanding around a near-classical path, chosen so that up to some predetermined
order there is no need to add any correction terms to the leading order
approximation. Both Complex WKB and BOMCA give the same leading order
approximation; in Complex WKB higher accuracy is achieved by adding correction
terms, while in BOMCA no additional terms are ever added -higher accuracy is
achieved by changing the path along which the original approximation is
computed. The path integral derivation of the methods explains the need to
incorporate contributions from more than one trajectory, as observed in
previous numerical work. On the other hand, it emerges that the methods provide
efficient schemes for computing the higher order terms in the asymptotic
evaluation of path integrals. The understanding we develop of BOMCA suggests
that there should exist near-classical trajectories that give exact quantum
dynamical results when used in the computation of the path integral keeping
just the leading order term. We also apply our path integral techniques to give
a compact derivation of the semiclassical approximation to the coherent state
propagator.


title: Spin-Torque-Induced Rotational Dynamics of a Magnetic Vortex Dipole

abstract:
  We study, both experimentally and by numerical modeling, the magnetic
dynamics that can be excited in a magnetic thin-film nanopillar device using
the spin torque from a spatially localized current injected via a
10s-of-nm-diameter aperture. The current-driven magnetic dynamics can produce
large amplitude microwave emission at zero magnetic field, with a frequency
well below that of the uniform ferromagnetic resonance mode. Micromagnetic
simulations indicate that the physical origin of this efficient microwave
nano-oscillator is the nucleation and subsequent steady-state rotational
dynamics of a magnetic vortex dipole driven by the localized spin torque. These
results show this novel implementation of a spintronic nano-oscillator is a
promising candidate for microwave technology applications.


title:
Modules of finite homological dimension with respect to a semidualizing
  module

abstract:
  We prove versions of results of Foxby and Holm about modules of finite
(Gorenstein) injective dimension and finite (Gorenstein) projective dimension
with respect to a semidualizing module. We also verify special cases of a
question of Takahashi and White.


title:
Quantum phase transitions, entanglement, and geometric phases of two
  qubits

abstract:
  The relation between quantum phase transitions, entanglement, and geometric
phases is investigated with a system of two qubits with XY type interaction. A
seam of level crossings of the system is a circle in parameter space of the
anisotropic coupling and the transverse magnetic field, which is identical to
the disorder line of an one-dimensional XY model. The entanglement of the
ground state changes abruptly as the parameters vary across the circle except
specific points crossing to the straight line of the zero magnetic field. At
those points the entanglement does not change but the ground state changes
suddenly. This is an counter example that the entanglement is not alway a good
indicator to quantum phase transitions. The rotation of the circle about an
axis of the parameter space produces the magnetic monopole sphere like a
conducting sphere of electrical charges. The ground state evolving
adiabatically outside the sphere acquires a geometric phase, whereas the ground
state traveling inside the sphere gets no geometric phase. The system also has
the Renner-Teller intersection which gives no geometric phases.


title: Gamma shape mixtures for heavy-tailed distributions

abstract:
  An important question in health services research is the estimation of the
proportion of medical expenditures that exceed a given threshold. Typically,
medical expenditures present highly skewed, heavy tailed distributions, for
which (a) simple variable transformations are insufficient to achieve a
tractable low-dimensional parametric form and (b) nonparametric methods are not
efficient in estimating exceedance probabilities for large thresholds.
Motivated by this context, in this paper we propose a general Bayesian approach
for the estimation of tail probabilities of heavy-tailed distributions, based
on a mixture of gamma distributions in which the mixing occurs over the shape
parameter. This family provides a flexible and novel approach for modeling
heavy-tailed distributions, it is computationally efficient, and it only
requires to specify a prior distribution for a single parameter. By carrying
out simulation studies, we compare our approach with commonly used methods,
such as the log-normal model and nonparametric alternatives. We found that the
mixture-gamma model significantly improves predictive performance in estimating
tail probabilities, compared to these alternatives. We also applied our method
to the Medical Current Beneficiary Survey (MCBS), for which we estimate the
probability of exceeding a given hospitalization cost for smoking attributable
diseases. We have implemented the method in the open source GSM package,
available from the Comprehensive R Archive Network.


title: Fourier-transform spectroscopy of Sr2 and revised ground state potential

abstract:
  Precise potentials for the ground state X1Sigma+g and the minimum region of
the excited state 2_1Sigma+u of Sr2 are derived by high resolution
Fourier-transform spectroscopy of fluorescence progressions from single
frequency laser excitation of Sr2 produced in a heat pipe at 950 Celsius. A
change of the rotational assignment by four units compared to an earlier work
(G. Gerber, R. M\"oller, and H. Schneider, J. Chem. Phys. 81, 1538 (1984)) is
needed for a consistent description leading to a significant shift of the
potentials towards longer inter atomic distances. The huge amount of ground
state data derived for the three different isotopomers 88Sr2, 86Sr88Sr and
87Sr88Sr (almost 60% of all excisting bound rovibrational ground state levels
for the isotopomer 88Sr2) fixes this assignment undoubtedly. The presented
ground state potential is derived from the observed transitions for the radial
region from 4 to 11 A (9 cm-1 below the asymptote) and is extended to the longe
range region by the use of theoretical dispersion coefficients together with
already available photoassociation data. New estimations of the scattering
lengths for the complete set of isotopic combinations are derived by mass
scaling with the derived potential. The data set for the excited state
2_1Sigma+u was sufficient to derive a potential energy curve around the
minimum.


title: A Strong Law of Large Numbers for Strongly Mixing Processes

abstract:
  We prove a strong law of large numbers for a class of strongly mixing
processes. Our result rests on recent advances in understanding of
concentration of measure. It is simple to apply and gives finite-sample (as
opposed to asymptotic) bounds, with readily computable rate constants. In
particular, this makes it suitable for analysis of inhomogeneous Markov
processes. We demonstrate how it can be applied to establish an almost-sure
convergence result for a class of models that includes as a special case a
class of adaptive Markov chain Monte Carlo algorithms.


title: Searching for Nambu-Goldstone Bosons at the LHC

abstract:
  Phenomenological implications of a minimal extension to the Standard Model
are considered, in which a Nambu-Goldstone boson emerges from the spontaneous
breaking of a global U(1) symmetry. This is felt only by a scalar field which
is a singlet under all Standard Model symmetries, and possibly by neutrinos.
Mixing between the Standard Model Higgs boson field and the new singlet field
may lead to predominantly invisible Higgs boson decays. The "natural" region in
the Higgs boson mass spectrum is determined, where this minimally extended
Standard Model is a valid theory up to a high scale related with the smallness
of neutrino masses. Surprisingly, this region may coincide with low visibility
of all Higgs bosons at the LHC. Monte-Carlo simulation studies of this
"nightmare" situation are performed and strategies to search for such Higgs
boson to invisible (Nambu-Goldstone boson) decays are discussed. It is possible
to improve the signal-to-background ratio by looking at the distribution of
either the total transverse momentum of the leptons and the missing transverse
momentum, or by looking at the distribution of the azimuthal angle between the
missing transverse momentum and the momentum of the lepton pair for the Z- and
Higgs-boson associated production. We also study variations of the model with
non-Abelian symmetries and present approximate formulae for Higgs boson decay
rates. Searching for Higgs bosons in such a scenario at the LHC would most
likely be solely based on Higgs to "invisible" decays.


title:
Equilibrium long-ranged charge correlations at the surface of a
  conductor coupled to the electromagnetic radiation

abstract:
  This study is related to the fluctuation theory of electromagnetic fields,
charges and currents. The three-dimensional system under consideration is a
semi-infinite conductor, modeled by the jellium, in vacuum. In previous
theoretical studies it was found that the correlation functions of the surface
charge density on the conductor decay as the inverse cube of the distance at
asymptotically large distances. The prefactor to this asymptotic decay was
obtained in the classical limit and in the quantum case without retardation
effects. To describe the retarded regime, we study a more general problem of
the semi-infinite jellium in thermal equilibrium with the radiated
electromagnetic field. By using Rytov's fluctuational electrodynamics we show
that, for both static and time-dependent surface charge correlation functions,
the inclusion of retardation effects causes the quantum prefactor to take its
universal static classical form, for any temperature.


title:
Automatised full one-loop renormalisation of the MSSM I: The Higgs
  sector, the issue of tan(beta) and gauge invariance

abstract:
  We give an extensive description of the renormalisation of the Higgs sector
of the minimal supersymmetric model in SloopS. SloopS is an automatised code
for the computation of one-loop processes in the MSSM. In this paper, the first
in a series, we study in detail the non gauge invariance of some definitions of
tan(beta). We rely on a general non-linear gauge fixing constraint to make the
gauge parameter dependence of different schemes for tan(beta) at one-loop
explicit. In so doing, we update, within these general gauges, an important
Ward-Slavnov-Taylor identity on the mixing between the pseudo-scalar Higgs,
A^0, and the Z^0. We then compare the tan(beta) scheme dependence of a few
observables. We find that the best tan(beta) scheme is the one based on the
decay A^0 -> tau^+ tau^- because of its gauge invariance, being unambiguously
defined from a physical observable, and because it is numerically stable. The
oft used DRbar scheme performs almost as well on the last count, but is usually
defined from non-gauge invariant quantities in the Higgs sector. The use of the
heavier scalar Higgs mass in lieu of tan(beta) though related to a physical
parameter induces too large radiative corrections in many instances and is
therefore not recommended.


title: Relativistic Outflows in two quasars in the Chandra Deep Field South

abstract:
  In this paper, we provide new 1 Ms $Chandra$ ACIS spectra of two quasars in
the Chandra Deep Field South (CDF-S), which were previously reported to show
strong and extremely blueshifted X-ray emission/absorption line features in
previous 1 Ms spectra, with outflowing bulk velocity $v\sim$0.65-0.84c. In the
new 1 Ms spectra, the relativistic blueshifted line feature is solidly
confirmed in CXO CDFS J033225.3-274219 (CDFS 46, $z$ = 1.617), and marginally
visible in CXO CDFS J033260.0-274748 (CDFS 11, $z$ = 2.579), probably due to
the increased Chandra ACIS background in the new 1 Ms exposure. The new data
rule out the possibility (though very tiny already based on the old 1Ms data)
that the two sources were selected to be unusual due to noise spikes in the
spectra. The only likely interpretation is extremely blueshifted iron
absorption/emission line or absorption edge due to relativistic outflow. We
find that the rest frame emission line center in CDFS 46 marginally decreased
from 16.2 keV to 15.2 keV after 7 years. The line shift can be due to either
decreasing outflowing velocity or lower ionization level. Including the two
quasars reported in this paper, we collect from literature a total of 7 quasars
showing blueshifted emission or absorption line feature with $v\geq0.4c$ in
X-ray spectra, and discuss its connection to jet and/or BAL (broad absorption
line) outflow.


title:
Harmonic oscillator with time-dependent effective-mass and frequency
  with a possible application to 'chirped tidal' gravitational waves forces
  affecting interferometric detectors

abstract:
  The general theory of time-dependent frequency and time-dependent mass
('effective mass') is described.The general theory for time-dependent harmonic-
oscillator is applied in the present research for studying certain quantum
effects in the interferometers for detecting gravitational waves.When an
astronomical binary system approaches its point of coalescence the
gravitational wave intensity and frequency are increasing and this can lead to
strong deviations from the simple description of harmonic-oscillations for the
interferometric masses on which the mirrors are placed.It is shown that under
such condtions the harmonic-oscillations of these masses can be described by
mechanical harmonic-oscillators with time-dependent frequency and
effective-mass. In the present theoretical model the effective-mass is
decreasing with time describing pumping phenomena in which the oscillator
amplitude is increasing with time . The quantization of this system is analyzed
by the use of the adiabatic approximation. It is found that the increase of the
gravitational wave intensity, within the adiabatic approximation, leads to
squeezing phenomena where the quantum noise in one quadrature is increased and
in the other quadrature is decreased.


title:
Codes Associated with $O^+(2n,2^r)$ and Power Moments of Kloosterman
  Sums

abstract:
  In this paper, we construct three binary linear codes $C(SO^+(2,q))$,
$C(O^+(2,q))$, $C(SO^+(4,q))$, respectively associated with the orthogonal
groups $SO^+(2,q)$, $O^+(2,q)$, $SO^+(4,q)$, with $q$ powers of two. Then we
obtain recursive formulas for the power moments of Kloosterman and
2-dimensional Kloosterman sums in terms of the frequencies of weights in the
codes. This is done via Pless power moment identity and by utilizing the
explicit expressions of Gauss sums for the orthogonal groups. We emphasize
that, when the recursive formulas for the power moments of Kloosterman sums are
compared, the present one is computationally more effective than the previous
one constructed from the special linear group $SL(2,q)$. We illustrate our
results with some examples.


title:
Quantitative magnetic resonance image analysis via the EM algorithm with
  stochastic variation

abstract:
  Quantitative Magnetic Resonance Imaging (qMRI) provides researchers insight
into pathological and physiological alterations of living tissue, with the help
of which researchers hope to predict (local) therapeutic efficacy early and
determine optimal treatment schedule. However, the analysis of qMRI has been
limited to ad-hoc heuristic methods. Our research provides a powerful
statistical framework for image analysis and sheds light on future localized
adaptive treatment regimes tailored to the individual's response. We assume in
an imperfect world we only observe a blurred and noisy version of the
underlying pathological/physiological changes via qMRI, due to measurement
errors or unpredictable influences. We use a hidden Markov random field to
model the spatial dependence in the data and develop a maximum likelihood
approach via the Expectation--Maximization algorithm with stochastic variation.
An important improvement over previous work is the assessment of variability in
parameter estimation, which is the valid basis for statistical inference. More
importantly, we focus on the expected changes rather than image segmentation.
Our research has shown that the approach is powerful in both simulation studies
and on a real dataset, while quite robust in the presence of some model
assumption violations.


title:
Determination of volume, shape and refractive index of individual blood
  platelets

abstract:
  Light scattering patterns (LSP) of blood platelets were theoretically and
experimentally analyzed. We used spicular spheroids as a model for the
platelets with pseudopodia. The discrete dipole approximation was employed to
simulate light scattering from an individual spicular spheroid constructed from
a homogeneous oblate spheroid and 14 rectilinear parallelepipeds rising from
the cell centre. These parallelepipeds have a weak effect on the LSP over the
measured angular range. Therefore, a homogeneous oblate spheroid was taken as a
simplified optical model for platelets. Using the T-matrix method, we computed
the LSP over a range of volumes, aspect ratios and refractive indices. Measured
LSPs of individual platelets were compared one by one with the theoretical set
and the best fit was taken to characterize the measured platelets, resulting in
distributions of volume, aspect ratio and refractive index.


title: How to Compute a Puiseux Expansion

abstract:
  In this paper, an explanation of the Newton-Peiseux algorithm is given. This
explanation is supplemented with well-worked and explained examples of how to
use the algorithm to find fractional power series expansions for all branches
of a polynomial at the origin.


title: Spontaneous Charging and Crystallization of Water Droplets in Oil

abstract:
  We study the spontaneous charging and the crystallization of spherical
micron-sized water-droplets dispersed in oil by numerically solving, within a
Poisson-Boltzmann theory in the geometry of a spherical cell, for the density
profiles of the cations and anions in the system. We take into account
screening, ionic Born self-energy differences between oil and water, and
partitioning of ions over the two media. We find that the surface charge
density of the droplet as induced by the ion partitioning is significantly
affected by the droplet curvature and by the finite density of the droplets. We
also find that the salt concentration and the dielectric constant regime in
which crystallization of the water droplets is predicted is enhanced
substantially compared to results based on the planar oil-water interface,
thereby improving quantitative agreement with recent experiments.


title:
Feasibility of acoustic neutrino detection in ice: Design and
  performance of the South Pole Acoustic Test Setup (SPATS)

abstract:
  The South Pole Acoustic Test Setup (SPATS) has been built to evaluate the
acoustic characteristics of the South Pole ice in the 10 to 100 kHz frequency
range so that the feasibility and specific design of an acoustic neutrino
detection array at South Pole can be evaluated. SPATS consists of three
vertical strings that were deployed in the upper 400 meters of the South Pole
ice cap in January 2007, using the upper part of IceCube holes. The strings
form a triangular array with the longest baseline 421 meters. Each of them has
7 stages with one transmitter and one sensor module. Both are equipped with
piezoelectric ceramic elements in order to produce or detect sound. Analog
signals are brought to the surface on electric cables where they are digitized
by a PC-based data acquisition system. The data from all three strings are
collected on a master-PC in a central facility, from which they are sent to the
northern hemisphere via a satellite link or locally stored on tape. A technical
overview of the SPATS detector and its performance is presented.


title:
Raman scattering investigation across the magnetic and MI transition in
  rare earth nickelate RNiO3 (R = Sm, Nd) thin films

abstract:
  We report a temperature-dependent Raman scattering investigation of thin film
rare earth nickelates SmNiO3, NdNiO3 and Sm0.60Nd0.40NiO3, which present a
metal-to-insulator (MI) transition at TMI and an antiferromagnetic-paramagnetic
Neel transition at TN. Our results provide evidence that all investigated
samples present a structural phase transition at TMI but the Raman signature
across TMI is significantly different for NdNiO3 (TMI = TN) compared to SmNiO3
and Sm0.60Nd0.40NiO3 (TMI =/ TN). It is namely observed that the
paramagnetic-insulator phase (TN < T < TMI) in SmNiO3 and Sm0.60Nd0.40NiO3 is
characterized by a pronounced softening of one particular phonon band around
420 cm-1. This signature is unusual and points to an important and continuous
change in the distortion of NiO6 octahedra (thus the Ni-O bonding) which
stabilizes upon cooling at the magnetic transition. The observed behaviour
might well be a general feature for all rare earth nickelates with TMI =/ TN
and illustrates intriguing coupling mechanism in the TMI > T > TN regime.


title:
Crossing the cosmological constant line in a dilatonic brane-world model
  with and without curvature corrections

abstract:
  We construct a new brane-world model composed of a bulk -with a dilatonic
field-, plus a brane -with brane tension coupled to the dilaton-, cold dark
matter and an induced gravity term. It is possible to show that depending on
the nature of the coupling between the brane tension and the dilaton this model
can describe the late-time acceleration of the brane expansion (for the normal
branch) as it moves within the bulk. The acceleration is produced together with
a mimicry of the crossing of the cosmological constant line (w=-1) on the
brane, although this crossing of the phantom divide is obtained without
invoking any phantom matter neither on the brane nor in the bulk. The role of
dark energy is played by the brane tension, which reaches a maximum positive
value along the cosmological expansion of the brane. It is precisely at that
maximum that the crossing of the phantom divide takes place. We also show that
these results remain valid when the induced gravity term on the brane is
switched off.


title:
Relations Involving Static Quadrupole Moments of $2^+$ states and
  B(E2)'s

abstract:
  We define the ``quadrupole ratio'' $r_Q = \dfrac{Q_0(S)}{Q_0(B)}$ where
$Q_0(S)$ is the intrinsic quadrupole moment obtained from the static quadrupole
moment of the $2_1^+$ state of an even-even nucleus and $Q_0(B)$ the intrinsic
quadrupole moment obtained from $B(E2)_{0 \to 2}$. In both cases we assume a
simple rotational formula connecting the rotating frame to the laboratory
frame. The quantity $r_Q$ would be one if the rotational model were perfect and
the energy ratio $E(4)/E(2)$ would be 10/3. In the simple vibrational model,
$r_Q$ would be zero and $E(4)/E(2)$ would be two. There are some regions where
the rotational limit is almost met and fewer where the vibrational limit is
also almost met. For most cases, however, it is between these two limits, i.e.
$0 < r_Q < 1$. There are a few cases where $r_Q$ is bigger than one, especially
for light nuclei.


title: Hacia una teoria de unificacion para los comportamientos cognitivos

abstract:
  Each cognitive science tries to understand a set of cognitive behaviors. The
structuring of knowledge of this nature's aspect is far from what it can be
expected about a science. Until now universal standard consistently describing
the set of cognitive behaviors has not been found, and there are many questions
about the cognitive behaviors for which only there are opinions of members of
the scientific community. This article has three proposals. The first proposal
is to raise to the scientific community the necessity of unified the cognitive
behaviors. The second proposal is claim the application of the Newton's
reasoning rules about nature of his book, Philosophiae Naturalis Principia
Mathematica, to the cognitive behaviors. The third is to propose a scientific
theory, currently developing, that follows the rules established by Newton to
make sense of nature, and could be the theory to explain all the cognitive
behaviors.


title:
Medium-energy ion-scattering study of strained holmium silicide
  nanoislands grown on silicon (100)

abstract:
  We have used medium-energy ion scattering (MEIS) to quantitatively analyze
the structure of holmium silicide islands grown on the Si(100) surface.
Structure fitting to the experimental data unambiguously shows that the
tetragonal silicide phase is present and not the hexagonal phase, which is
associated with the growth of nanowires at submonolayer coverages. Islands
formed with a lower holmium coverage of 3 ML are also shown to be tetragonal,
which suggests that the hexagonal structure is not a low coverage precursor to
the growth of the tetragonal phase. MEIS simulations of large nanoislands,
which include the effects of lateral strain relief, have been performed and
these compare well with the experimental data.


title: Higher Powers in Gravitation

abstract:
  We consider the Friedmann-Robertson-Walker cosmologies of theories of gravity
that generalise the Einstein-Hilbert action by replacing the Ricci scalar, R,
with some function, f(R). The general asymptotic behaviour of these cosmologies
is found, at both early and late times, and the effects of adding higher and
lower powers of R to the Einstein-Hilbert action is investigated. The
assumption that the highest powers of R should dominate the Universe's early
history, and that the lowest powers should dominate its future is found to be
inaccurate. The behaviour of the general solution is complicated, and while it
can be the case that single powers of R dominate the dynamics at late times, it
can be either the higher or lower powers that do so. It is also shown that it
is often the lowest powers of R that dominate at early times, when approach to
a bounce or a Tolman solution are generic possibilities. Various examples are
considered, and both vacuum and perfect fluid solutions investigated.


title: The Generalized Effros-Hahn Conjecture for Groupoids

abstract:
  The generalized Effros-Hahn conjecture for groupoid C*-algebras says that, if
G is amenable, then every primitive ideal of the groupoid C*-algebra C*(G) is
induced from a stability group. We prove that the conjecture is valid for all
second countable amenable locally compact Hausdorff groupoids. Our results are
a sharpening of previous work of Jean Renault and depend significantly on his
results.


title: The smooth representations of GL_2(O)

abstract:
  We present some unpublished results of Kutzko together with results of Hill,
giving a classification of the smooth (complex) representations of
$\mathrm{GL}_{2}(\mathcal{O})$, where $\mathcal{O}$ is the ring of integers in
a local field with finite residue field.


title: A note on the Jordan decomposition

abstract:
  In this article we prove that the elliptic, hyperbolic and nilpotent (or
unipotent) additive (or multiplicative) Jordan components of an endomorphism
$X$ (or an isomorphism $g$) of a finite dimensional vector space are given by
polynomials in $X$ (or in $g$). By using this, we provide a simple proof that,
for an element $X$ of a linear semisimple Lie algebra $\g$ (or $g$ of a linear
semisimple connected Lie group $G$), its three Jordan components lie again in
the algebra (in the group). This was previously unknown for linear Lie groups
other then $\Int(\g)$. This implies that, for this class of algebras and
groups, the usual linear Jordan decomposition coincides with the abstract
Jordan decomposition.


title: Hadronic three-body decays of light vector mesons

abstract:
  The decays of light vector mesons into three pseudoscalar mesons are
calculated to leading order in the recently proposed counting scheme that is
based on the hadrogenesis conjecture. Fully differential as well as integrated
decay widths are presented. Since the required parameters have been fixed by
other processes, the considered three-body decays are predictions of the
presented approach. The decay width of the omega meson into three pions agrees
very well with experiment. The partial decay widths of the K^* into its three
K-pi-pi channels are predicted.


title:
On the Star Formation Rate - Brightest Cluster Relation: Estimating the
  peak SFR in post-merger galaxies

abstract:
  We further the recent discussion on the relation between the star-formation
rate (SFR) of a galaxy and the luminosity of its brightest star-cluster (SFR
vs. M$_{V}^{brightest}$). We first show that the observed trend between SFR vs.
M$_{V}^{brightest}$ is due to the brightest cluster in a galaxy being
preferentially young (<15 Myr - for a constant SFR) and hence a good tracer of
the current SFR, although we give notable exceptions to this rule. Using a
series of Monte Carlo simulations we show that a pure power-law mass function
with index, alpha=2, is ruled out by the current data. Instead we find that a
Schechter function (i.e. a power-law with an exponential truncation at the high
mass end) provides an excellent fit to the data. Additionally, these
simulations show that bound cluster formation (in Msun/yr) represents only
~8+-3% of the total star-formation within a galaxy, independent of the
star-formation rate. From this we conclude that there is only a single mode of
cluster formation which operates over at least six orders of magnitude in the
SFR. Using this relation, we can extrapolate backwards in time in order to
estimate the peak SFR of major merger galaxies, such as NGC7252, NGC1316 and
NGC3610. The derived SFRs for these galaxies are between a few hundred and a
few thousand solar masses per year. The inferred far infrared luminosity of the
galaxies, from the extrapolated SFR, places them well within the range of
Ultra-luminous galaxies (ULIRGs) and for NGC 7252 within the Hyper-luminous
infrared galaxy regime. Thus, we provide evidence that these post merger
galaxies passed through a ULIRG/HLIRG phase and are now evolving passively.
Using the current and extrapolated past SFR of NGC 34, we infer that the ULIRG
phase of this galaxy has lasted for at least 150 Myr.


title: Estimating Jones and HOMFLY polynomials with One Clean Qubit

abstract:
  The Jones and HOMFLY polynomials are link invariants with close connections
to quantum computing. It was recently shown that finding a certain
approximation to the Jones polynomial of the trace closure of a braid at the
fifth root of unity is a complete problem for the one clean qubit complexity
class. This is the class of problems solvable in polynomial time on a quantum
computer acting on an initial state in which one qubit is pure and the rest are
maximally mixed. Here we generalize this result by showing that one clean qubit
computers can efficiently approximate the Jones and single-variable HOMFLY
polynomials of the trace closure of a braid at any root of unity.


title:
Magnetic and electric properties of double-perovskites and estimation of
  their Curie temperatures by ab initio calculations

abstract:
  First principles electronic structure calculations have been carried out on
ordered double perovskites Sr_2B'B"O_6 (for B' = Cr or Fe and B" 4d and 5d
transition metal elements) with increasing number of valence electrons at the
B-sites, and on Ba_2MnReO_6 as well as Ba_2FeMoO_6. The Curie temperatures are
estimated ab initio from the electronic structures obtained with the local
spin-density functional approximation, full-potential generalized gradient
approximation and/or the LDA+U method (U - Hubbard parameter). Frozen
spin-spirals are used to model the excited states needed to evaluate the
spherical approximation for the Curie temperatures. In cases, where the induced
moments on the oxygen was found to be large, the determination of the Curie
temperature is improved by additional exchange functions between the oxygen
atoms and between oxygen and B' and B" atoms.
  A pronounced systematics can be found among the experimental and/or
calculated Curie temperatures and the total valence electrons of the transition
metal elements.


title: Covariance fields

abstract:
  We introduce and study covariance fields of distributions on a Riemannian
manifold. At each point on the manifold, covariance is defined to be a
symmetric and positive definite (2,0)-tensor. Its product with the metric
tensor specifies a linear operator on the respected tangent space.
Collectively, these operators form a covariance operator field. We show that,
in most circumstances, covariance fields are continuous. We also solve the
inverse problem: recovering distribution from a covariance field. Surprisingly,
this is not possible on Euclidean spaces. On non-Euclidean manifolds however,
covariance fields are true distribution representations.


title:
Virtual Hadronic and Heavy-Fermion O(alpha^2) Corrections to Bhabha
  Scattering

abstract:
  Effects of vacuum polarization by hadronic and heavy-fermion insertions were
the last unknown two-loop QED corrections to high-energy Bhabha scattering and
have been first announced in \cite{Actis:2007fs}. Here we describe the
corrections in detail and explore their numerical influence. The hadronic
contributions to the virtual O(alpha^2) QED corrections to the
Bhabha-scattering cross-section are evaluated using dispersion relations and
computing the convolution of hadronic data with perturbatively calculated
kernel functions. The technique of dispersion integrals is also employed to
derive the virtual O(alpha^2) corrections generated by muon-, tau- and
top-quark loops in the small electron-mass limit for arbitrary values of the
internal-fermion masses. At a meson factory with 1 GeV center-of-mass energy
the complete effect of hadronic and heavy-fermion corrections amounts to less
than 0.5 per mille and reaches, at 10 GeV, up to about 2 per mille. At the Z
resonance it amounts to 2.3 per mille at 3 degrees; overall, hadronic
corrections are less than 4 per mille. For ILC energies (500 GeV or above), the
combined effect of hadrons and heavy-fermions becomes 6 per mille at 3 degrees;
hadrons contribute less than 20 per mille in the whole angular region.


title: Some sharp Hardy inequalities on spherically symmetric domains

abstract:
  We prove some sharp Hardy inequalities for domains with a spherical symmetry.
In particular, we prove an inequality for domains of the unit $n$-dimensional
sphere with a point singularity, and an inequality for functions defined on the
half-space $\R_+^{n+1}$} vanishing on the hyperplane $\{x_{n+1}=0\}$, with
singularity along the $x_{n+1}$-axis. The proofs rely on a one-dimensional
Hardy inequality involving a weight function related to the volume element on
the sphere, as well as on symmetrization arguments. The one-dimensional
inequality is derived in a general form.


title: Thermally activated Peierls dimerization in ferromagnetic spin chains

abstract:
  We demonstrate that a Peierls dimerization can occur in ferromagnetic spin
chains activated by thermal fluctuations. The dimer order parameter and
entanglement measures are studied as functions of the modulation of the
magnetic exchange interaction and temperature, using a spin-wave theory and the
density-matrix renormalization group. We discuss the case where a periodic
modulation is caused by spin-phonon coupling and the case where electronic
states effectively induce such a modulation. The importance of the latter for a
number of transition metal oxides is highlighted.


title: Reduction mod $\ell$ of Theta Series of Level $\ell^n$

abstract:
  It is proved that the theta series of an even lattice whose level is a power
of a prime $\ell$ is congruent modulo $\ell$ to an elliptic modular form of
level~1. The proof uses arithmetic and algebraic properties of lattices rather
than methods from the theory of modular forms. The methods presented here may
therefore be especially pleasing to those working in the theory of quadratic
forms, and they admit generalizations to more general types of theta series as
they occur e.g. in the theory of Siegel or Hilbert modular forms.


title:
Correlations of the IR Luminosity and Eddington Ratio with a Hard X-ray
  Selected Sample of AGN

abstract:
  We use the SWIFT Burst Alert Telescope (BAT) sample of hard x-ray selected
active galactic nuclei (AGN) with a median redshift of 0.03 and the 2MASS J and
K band photometry to examine the correlation of hard x-ray emission to
Eddington ratio as well as the relationship of the J and K band nuclear
luminosity to the hard x-ray luminosity. The BAT sample is almost unbiased by
the effects of obscuration and thus offers the first large unbiased sample for
the examination of correlations between different wavelength bands. We find
that the near-IR nuclear J and K band luminosity is related to the BAT (14 -
195 keV) luminosity over a factor of $10^3$ in luminosity ($L_{IR} \approx
L_{BAT}^{1.25}$)and thus is unlikely to be due to dust. We also find that the
Eddington ratio is proportional to the x-ray luminosity. This new result should
be a strong constraint on models of the formation of the broad band continuum.


title: Irreducibility criterion for the set of two matrices

abstract:
  We give the criterion for the irreducibility, the Schur irreducibility and
the indecomposability of the set of two $n\times n$ matrices $\Lambda_n$ and
$A_n$ in terms of the subalgebra associated with the "support" of the matrix
$A_n$, where $\Lambda_n$ is a diagonal matrix with different non zeros
eigenvalues and $A_n$ is an arbitrary one. The list of all maximal subalgebras
of the algebra ${\rm Mat}(n,{\mathbb C})$ and the list of the corresponding
invariant subspaces connected with these two matrices is also given. The
properties of the corresponding subalgebras are expressed in terms of the
graphs associated with the support of the second matrix.
  For arbitrary $n$ we describe all minimal subsets of the elementary matrices
$E_{km}$ that generate the algebra ${\rm Mat}(n,{\mathbb C})$.


title:
Gravitational Radiation Driven Supermassive Black Hole Binary Inspirals
  as Periodically Variable Electromagnetic Sources

abstract:
  Supermassive black hole binaries (SMBHBs) produced in galaxy mergers are
thought to complete their coalescence, below separations of r_GW=10^{-3}
(M_BH/10^8 M_sun)^{3/4} pc, as their orbit decays due to the emission of
gravitational waves (GWs). It may be possible to identify such GW-driven
inspirals statistically in an electromagnetic (EM) survey for variable sources.
A GW-driven binary spends a characteristic time T_GW at each orbital separation
r_orb < r_GW that scales with the corresponding orbital time t_orb as T_GW =
(const) t_orb^{8/3}. If the coalescing binary produces variations in the EM
emission on this timescale, then it could be identified as a variable source
with a characteristic period t_var = t_orb. The incidence rate of sources with
similar inferred BH masses, showing near-periodic variability on the time-scale
t_var, would then be proportional to t_var^{8/3}. Luminosity variations
corresponding to a fraction f_Edd<0.01 of the Eddington luminosity would have
been missed in current surveys. However, if the binary inspirals are associated
with quasars, we show that a dedicated survey could detect the population of
SMBHBs with a range of periods around tens of weeks. The discovery of a
population of periodic sources whose abundance obeys N_var = (const)
t_var^{8/3} would confirm (i) that the orbital decay is indeed driven by GWs,
and (ii) that circumbinary gas is present at small orbital radii and is being
perturbed by the BHs. Deviations from the t_var^{8/3} power-law could constrain
the structure of the circumbinary gas disk and viscosity-driven orbital decay.
We discuss constraints from existing data, and quantify the sensitivity and sky
coverage that could yield a detection in future surveys.


title: The ice-limit of Coulomb gauge Yang-Mills theory

abstract:
  In this paper we describe gauge invariant multi-quark states generalising the
path integral framework developed by Parrinello, Jona-Lasinio and Zwanziger to
amend the Faddeev-Popov approach. This allows us to produce states such that,
in a limit which we call the ice-limit, fermions are dressed with glue
exclusively from the fundamental modular region associated with Coulomb gauge.
The limit can be taken analytically without difficulties, avoiding the Gribov
problem. This is llustrated by an unambiguous construction of gauge invariant
mesonic states for which we simulate the static quark--antiquark potential.


title:
Space-Time Correlations in the Orientational Order Parameter and the
  Orientational Entropy of Water

abstract:
  We introduce the spatial correlation function $C_Q(r)$ and temporal
autocorrelation function $C_Q(t)$ of the local tetrahedral order parameter
$Q\equiv Q(r,t)$. Using computer simulations of the TIP5P model of water, we
investigate $C_Q(r)$ in a broad region of the phase diagram. First we show that
$C_Q(r)$ displays anticorrelation at $r\approx 0.32$nm at high temperatures
$T>T_W\approx 250$ K, which changes to positive correlation below the Widom
line $T_W$. Further we find that at low temperatures $C_Q(t)$ exhibits a
two-step temporal decay similar to the self intermediate scattering function,
and that the corresponding correlation time $\tau_Q$ displays a dynamic
crossover from non-Arrhenius behavior for $T>T_W$ to Arrhenius behavior for
$T<T_W$. Finally, we define an orientational entropy $S_Q$ associated with the
{\it local} orientational order of water molecules, and show that $\tau_Q$ can
be extracted from $S_Q$ using an analog of the Adam-Gibbs relation.


title:
Rescaled weighted random balls models and stable self-similar random
  fields

abstract:
  We consider weighted random balls in $\real^d$ distributed according to a
random Poisson measure with heavy-tailed intensity and study the asymptotic
behaviour of the total weight of some configurations in $\real^d$. This
procedure amounts to be very rich and several regimes appear in the limit,
depending on the intensity of the balls, the zooming factor, the tail
parameters of the radii and of the weights. Statistical properties of the limit
fields are also evidenced, such as isotropy, self-similarity or dependence. One
regime is of particular interest and yields $\alpha$-stable stationary
isotropic self-similar generalized random fields which recovers Takenaka
fields, Telecom process or fractional Brownian motion.


title: An image processing analysis of skin textures

abstract:
  Colour and coarseness of skin are visually different. When image processing
is involved in the skin analysis, it is important to quantitatively evaluate
such differences using texture features. In this paper, we discuss a texture
analysis and measurements based on a statistical approach to the pattern
recognition. Grain size and anisotropy are evaluated with proper diagrams. The
possibility to determine the presence of pattern defects is also discussed.


title: The Assembly of Supermassive Black Holes at High Redshifts

abstract:
  The supermassive black holes (SMBHs) massive enough to power the bright
redshift ~6 quasars observed in the Sloan Digital Sky Survey (SDSS) are thought
to have assembled by mergers and/or gas accretion from less massive "seed" BHs.
If the seeds are the ~100 Msol remnant BHs from the first generation of stars,
they must be in place well before redshift z=6, and must avoid being ejected
from their parent proto-galaxies by the large (few hundred km/s) kicks they
suffer from gravitational-radiation induced recoil during mergers with other
BHs. We simulate the SMBH mass function at redshift z=6 using dark matter (DM)
halo merger trees, coupled with a prescription for the halo occupation
fraction, accretion histories, and radial recoil trajectories of the growing
BHs. Our purpose is (i) to map out plausible scenarios for successful assembly
of the z~6 quasar BHs by exploring a wide region of parameter space, and (ii)
to predict the rate of low-frequency gravitational wave events detectable by
the Laser Interferometer Space Antenna (LISA) for each such scenario. Our main
findings are as follows: (1) ~100 Msol seed BHs can grow into the SDSS quasar
BHs without super--Eddington accretion, but only if they form in minihalos by
z~30 and subsequently accrete ~60% of the time; (2) the scenarios with
optimistic assumptions required to explain the SDSS quasar BHs overproduce the
mass density in lower--mass (10^5 to 10^7 Msol) SMBHs by a factor of 100-1000,
unless seeds stop forming, or accrete at a severely diminished rates or duty
cycles (e.g. due to feedback), at z < 20-30. We also present several successful
assembly models and their LISA detection rates, including a "maximal" model
that gives the highest rate (~30/yr at z~6) without overproducing the total
SMBH density.


title: Topologically Massive Gravity at the Chiral Point is Not Unitary

abstract:
  A recent paper [arXiv:0801.4566] claims that topologically massive gravity
contains only chiral boundary excitations at a particular value of the
Chern-Simons coupling. On the other hand, propagating bulk degrees of freedom
were found even at the chiral point in [arXiv:0803.3998]. The two references
use very different methods, making comparison of their respective claims
difficult. In this letter, we use the method of [arXiv:0801.4566] to construct
a tower of propagating bulk states satisfying standard AdS boundary conditions.
Our states have finite norm, with sign opposite to that of right-moving
boundary excitations. Our results thus agree with [arXiv:0803.3998] and
disagree with [arXiv:0801.4566].


title: Large scale geometry of commutator subgroups

abstract:
  Let G be a finitely presented group, and G' its commutator subgroup. Let C be
the Cayley graph of G' with all commutators in G as generators. Then C is large
scale simply connected. Furthermore, if G is a torsion-free nonelementary
word-hyperbolic group, C is one-ended. Hence (in this case), the asymptotic
dimension of C is at least 2.


title: Quantitative imaging of colloidal flows

abstract:
  We present recent advances in the instrumentation and analysis methods for
quantitative imaging of concentrated colloidal suspensions under flow. After a
brief review of colloidal imaging, we describe various flow geometries for two
and and three-dimensional (3D) imaging, including a `confocal rheoscope'. This
latter combination of a confocal microscope and a rheometer permits
simultaneous characterization of rheological response and 3D microstructural
imaging. The main part of the paper discusses in detail how to identify and
track particles from confocal images taken during flow. After analyzing the
performance of the most commonly used colloid tracking algorithm by Crocker and
Grier extended to flowing systems, we propose two new algorithms for reliable
particle tracking in non-uniform flows to the level of accuracy already
available for quiescent systems. We illustrate the methods by applying it to
data collected from colloidal flows in three different geometries (channel
flow, parallel plate shear and cone-plate rheometry).