title: Toroidal field instability and eddy viscosity in Taylor-Couette flows

abstract:
  Toroidal magnetic fields subject to the Tayler instability can transport
angular momentum. We show that the Maxwell and Reynolds stress of the
nonaxisymmetric field pattern depend linearly on the shear in the cylindrical
gap geometry. Resulting angular momentum transport also scales linear with
shear. It is directed outwards for astrophysical relevant flows and directed
inwards for superrotating flows with dOmega/dR>0. We define an eddy viscosity
based on the linear relation between shear and angular momentum transport and
show that its maximum for given Prandtl and Hartmann number depends linear on
the magnetic Reynolds number Rm. For Rm=1000 the eddy viscosity is of the size
of 30 in units of the microscopic value.


title:
The p-adic analytic space of pseudocharacters of a profinite group and
  pseudorepresentations over arbitrary rings

abstract:
  Let G be a profinite group which is topologically finitely generated, p a
prime number and d an integer. We show that the functor from rigid analytic
spaces over Q_p to sets, which associates to a rigid space Y the set of
continuous d-dimensional pseudocharacters G -> O(Y), is representable by a
quasi-Stein rigid analytic space X, and we study its general properties. Our
main tool is a theory of "determinants" extending the one of pseudocharacters
but which works over an arbitrary base ring; an independent aim of this paper
is to expose the main facts of this theory. The moduli space X is constructed
as the generic fiber of the moduli formal scheme of continuous formal
determinants on G of dimension d. As an application to number theory, this
provides a framework to study the generic fibers of pseudodeformation rings
(e.g. of Galois representations), especially in the "residually reducible"
case, and including when p <= d.


title: Genetic Algorithms for multiple objective vehicle routing

abstract:
  The talk describes a general approach of a genetic algorithm for multiple
objective optimization problems. A particular dominance relation between the
individuals of the population is used to define a fitness operator, enabling
the genetic algorithm to adress even problems with efficient, but
convex-dominated alternatives. The algorithm is implemented in a multilingual
computer program, solving vehicle routing problems with time windows under
multiple objectives. The graphical user interface of the program shows the
progress of the genetic algorithm and the main parameters of the approach can
be easily modified. In addition to that, the program provides powerful decision
support to the decision maker. The software has proved it's excellence at the
finals of the European Academic Software Award EASA, held at the Keble college/
University of Oxford/ Great Britain.


title: Queue-length synchronization in a communication networks

abstract:
  We study synchronization in the context of network traffic on a $2-d$
communication network with local clustering and geographic separations. The
network consists of nodes and randomly distributed hubs where the top five hubs
ranked according to their coefficient of betweenness centrality (CBC) are
connected by random assortative and gradient mechanisms. For multiple message
traffic, messages can trap at the high CBC hubs, and congestion can build up on
the network with long queues at the congested hubs. The queue lengths are seen
to synchronize in the congested phase. Both complete and phase synchronization
is seen, between pairs of hubs. In the decongested phase, the pairs start
clearing, and synchronization is lost. A cascading master-slave relation is
seen between the hubs, with the slower hubs (which are slow to decongest)
driving the faster ones. These are usually the hubs of high CBC. Similar
results are seen for traffic of constant density. Total synchronization between
the hubs of high CBC is also seen in the congested regime. Similar behavior is
seen for traffic on a network constructed using the Waxman random topology
generator. We also demonstrate the existence of phase synchronization in real
Internet traffic data.


title:
Thermal disc emission from a rotating black hole: X-ray polarization
  signatures

abstract:
  Thermal emission from the accretion disc around a black hole can be
polarized, due to Thomson scattering in a disc atmosphere. In Newtonian space,
the polarization angle must be either parallel or perpendicular to the
projection of the disc axis on the sky. As first pointed out by Stark and
Connors in 1977, General Relativity effects strongly modify the polarization
properties of the thermal radiation as observed at infinity. Among these
effects, the rotation of the polarization angle with energy is particularly
useful as a diagnostic tool.
  In this paper, we extend the Stark and Connors calculations by including the
spectral hardening factor, several values of the optical depth of the
scattering atmosphere and rendering the results to the expected performances of
planned X-ray polarimeters. In particular, to assess the perspectives for the
next generation of X-ray polarimeters, we consider the expected sensitivity of
the detectors onboard the planned POLARIX and IXO missions. We assume the two
cases of a Schwarzschild and an extreme Kerr black hole with a standard thin
disc and a scattering atmosphere. We compute the expected polarization degree
and the angle as functions of the energy as they could be measured for
different inclinations of the observer, optical thickness of the atmosphere and
different values of the black hole spin. We assume the thermal emission
dominates the X-ray band. Using the flux level of the microquasar GRS 1915+105
in the thermal state, we calculate the observed polarization.


title: High-resolution radio continuum survey of M33: III. Magnetic fields

abstract:
  Using the linearly polarized intensity and polarization angle data at 3.6,
6.2 and 20 cm, we determine variations of Faraday rotation and depolarization
across the nearby galaxy M33. A 3-D model of the regular magnetic field is
fitted to the observed azimuthal distribution of polarization angles. Faraday
rotation, measured between 3.6 and 6.2 cm at a linear resolution of 0.7 kpc,
shows more variation in the south than in the north of the galaxy. About 10% of
the nonthermal emission from M33 at 3.6 cm is polarized. We estimate the
average total and regular magnetic field strengths in M33 as ~ 6.4 and 2.5
$\mu$G, respectively. Under the assumption that the disk of M33 is flat, the
regular magnetic field consists of horizontal and vertical components: however
the inferred vertical field may be partly due to a galactic warp. The
horizontal field is represented by an axisymmetric (m=0) mode from 1 to 3 kpc
radius and a superposition of axisymmetric and bisymmetric (m=0+1) modes from 3
to 5 kpc radius. An excess of differential Faraday rotation in the southern
half together with strong Faraday dispersion in the southern spiral arms seem
to be responsible for the north-south asymmetry in the observed wavelength
dependent depolarization. The presence of an axisymmetric m=0 mode of the
regular magnetic field in each ring suggests that a galactic dynamo is
operating in M33. The pitch angles of the spiral regular magnetic field are
generally smaller than the pitch angles of the optical spiral arms but are
twice as big as simple estimates based on the mean-field dynamo theory and
M33's rotation curve. Generation of interstellar magnetic fields from turbulent
gas motions in M33 is indicated by the equipartition of turbulent and magnetic
energy densities.


title: $\phi$ Meson Production in In-In Collisions and the $\phi$ Puzzle

abstract:
  The NA60 experiment measured dimuon production in In-In collisions at 158
AGeV. This paper presents a high statistics measurement of $\phi\to\mu\mu$ with
the specific objective to provide insight on the $\phi$ puzzle, i.e. the
difference in the inverse $T$ slopes and absolute yields measured by NA49 and
NA50 in the kaon and lepton channel, respectively. Transverse momentum
distributions were studied as a function of centrality. The slope parameter $T$
shows a rapid increase with centrality, followed by a saturation. Variations of
$T$ with the fit range of the order of 15 MeV were observed, possibly as a
consequence of radial flow. The $\phi$ meson yield normalized to the number of
participants increases with centrality and is consistently higher than the
yield measured by the NA49 experiment at any centrality.


title: Reflection matrices for the $U_{q}[osp(r|2m)^{(1)}]$ vertex model

abstract:
  The graded reflection equation is investigated for the
$U_{q}[osp(r|2m)^{(1)}]$ vertex model. We have found four classes of diagonal
solutions with at the most one free parameter and twelve classes of
non-diagonal ones with the number of free parameters depending on the number of
bosonic ($r$) and fermionic ($2m$) degrees of freedom.


title:
On the magic of transforming antikaonic nuclear broad quasibound states
  into narrow intrinsic decaying states

abstract:
  Comments are made on Akaishi, Myint and Yamazaki's interpretation of
antikaonic quasibound nuclear states as generalized Kapur-Peierls decaying
states [arXiv:0805.4382]. We argue that these `intrinsic decaying states' have
little to do with low-energy antikaon-nucleon dynamics.


title:
An extended existence result for quadratic BSDEs with jumps with
  application to the utility maximization problem

abstract:
  In this study, we consider the exponential utility maximization problem in
the context of a jump-diffusion model. To solve the problem, we rely on the
dynamic programming principle and we derive from it a quadratic BSDE with
jumps. Since this quadratic BSDE is driven both by a Wiener process and by a
Poisson random measure having a Levy measure with infinite mass, our main task
consists in establishing a new existence result for the specific BSDE
introduced.


title: Semispectral measures as convolutions and their moment operators

abstract:
  The moment operators of a semispectral measure having the structure of the
convolution of a positive measure and a semispectral measure are studied, with
paying attention to the natural domains of these unbounded operators. The
results are then applied to conveniently determine the moment operators of the
Cartesian margins of the phase space observables.


title: Diffractive Higgs boson photoproduction in $\gamma p$ process

abstract:
  We explore an alternative process for the diffractive Higgs boson production
in peripheral pp collisions arising from Double Pomeron Exchange in
photon-proton interaction. We introduce the impact factor formalism in order to
enable the gluon ladder exchange in the photon-proton subprocess, and to permit
the central Higgs production. The event rate for the diffractive Higgs
production in central rapidity is estimated to be about 0.6 pb at Tevatron and
LHC energies. This result is higher than predictions from other approaches for
diffractive Higgs production, showing that the alternative production process
leads to an enhanced signal for the detection of the Higgs boson at hadron
colliders. Our results are compared to those obtained from a similar approach
proposed by the Durham group. In this way we may examine the future
developments in its application to pp and AA collisions.


title:
Approximate Hamiltonian Statistics in One-dimensional Driven Dissipative
  Many-Particle Systems

abstract:
  This contribution presents a derivation of the steady-state distribution of
velocities and distances of driven particles on a onedimensional periodic ring.
We will compare two different situations: (i) symmetrical interaction forces
fulfilling Newton's law of "actio = reactio" and (ii) asymmetric, forwardly
directed interactions as, for example in vehicular traffic. Surprisingly, the
steady-state velocity and distance distributions for asymmetric interactions
and driving terms agree with the equilibrium distributions of classical
many-particle systems with symmetrical interactions, if the system is large
enough. This analytical result is confirmed by computer simulations and
establishes the possibility of approximating the steady state statistics in
driven many-particle systems by Hamiltonian systems. Our finding is also useful
to understand the various departure time distributions of queueing systems as a
possible effect of interactions among the elements in the respective queue [D.
Helbing et al., Physica A 363, 62 (2006)].


title:
Analysis of extremely low signal-to-noise ratio data from
  INTEGRAL/PICsIT

abstract:
  The PICsIT detector onboard the INTEGRAL satellite was designed to provide
information about emission in the soft gamma-ray band for many bright sources.
Due to strong and variable instrumental background, only 4 objects have been
detected so far using standard software. The moderate sensitivity of PICsIT can
be compensated for in the case of many objects by adopting a long exposure
time, thanks to INTEGRAL's large field of view. With angular resolution far
higher than that of all other instruments operating in a similar energy band,
PICsIT is suitable for fields too crowded or too significantly affected by
Galactic diffuse emission. Therefore, it is desirable to improve the spectral
extraction software to both obtain more reliable results and enlarge the number
of objects that can be studied. The new PICsIT spectral extraction method is
based on three elements: careful modelling of the background, an
energy-dependent pixel-illumination function, and the computation of the
probability density of the source count rate. The most important element is the
proper treatment of the Poisson-distributed data, developed within a Bayesian
framework. The new method was tested extensively on both a large true data set
and simulated data. Results assumed in simulations were reproduced perfectly,
without any bias and with high precision. Count rates measured for Crab were
far more stable than those obtained with the standard software. For weaker
sources, the new method produced spectra of far higher quality and allows us to
detect at least 8 additional objects. Comparison with other INTEGRAL
instruments demonstrated that PICsIT is well calibrated and provides valuable
information about the continuum emission in the 250 keV -- 1 MeV band.


title:
The probability distribution of internal stresses in externally loaded
  2D dislocation systems

abstract:
  The distribution of internal shear stresses in a 2D dislocation system is
investigated when external shear stress is applied. This problem serves as a
natural continuation of the previous work of Csikor and Groma (Csikor F F and
Groma I 2004 Phys. Rev. B 58 2969), where analytical result was given for the
stress distribution function at zero applied stress. First, the internal stress
distribution generated by a set of randomly positioned ideal dislocation
dipoles is studied. Analytical calculations are carried out for this case. The
theoretical predictions are checked by numerical simulations showing perfect
agreement. It is found that for real relaxed dislocation configurations the
role of dislocation multipoles cannot be neglected, but the theory presented
can still be applied.


title: Accretion and plasma outflow from dissipationless discs

abstract:
  We consider an extreme case of disc accretion onto a gravitating centre when
the viscosity in the disc is negligible. The angular momentum and the
rotational energy of the accreted matter is carried out by a magnetized wind
outflowing from the disc. The outflow of matter from the disc occurs due to the
Blandford & Payne(1982) centrifugal mechanism. The disc is assumed to be cold.
Accretion and outflow are connected by the conservation of the energy, mass and
the angular momentum. The basic properties of the outflow, angular momentum
flux and energy flux per particle in the wind, do not depend on the details of
the structure of the accretion disc. In the case of selfsimilar
accretion/outflow, the dependence of the rate of accretion $\dot M$ in the disc
depends on the disc radius $r$ on the law $\dot M \sim
r^{{1\over2(\alpha^2-1)}}$, where $\alpha$ is a dimensionless Alfvenic radius.
In the case of $\alpha \gg 1$, the accretion in the disc is provided by very
weak matter outflow from the disc and the outflow predominantly occurs from the
very central part of the disc. The solution obtained in the work provides
mechanism which transforms the gravitational energy of the accreted matter into
the energy of the outflowing wind with efficiency close to 100%. The final
velocity can essentially exceed Kepler velocity at the site of the wind launch.
This mechanism allows us to understand the nature of the astrophysical objects
with low luminosity discs and energetic jet-like outflows.


title:
Universality of state-independent violation of correlation inequalities
  for noncontextual theories

abstract:
  We show that the state-independent violation of inequalities for
noncontextual hidden variable theories introduced in [Phys. Rev. Lett. 101,
210401 (2008)] is universal, i.e., occurs for any quantum mechanical system in
which noncontextuality is meaningful. We describe a method to obtain
state-independent violations for any system of dimension d > 2. This
universality proves that, according to quantum mechanics, there are no
"classical" states.


title:
Discrete symmetries and the propagator approach to coupled fermions in
  Quantum Field Theory. Generalities. The case of a single fermion-antifermion
  pair

abstract:
  Starting from Wigner's symmetry representation theorem, we give a general
account of discrete symmetries (parity P, charge conjugation C, time-reversal
T), focusing on fermions in Quantum Field Theory. We provide the rules of
transformation of Weyl spinors, both at the classical level (grassmanian wave
functions) and quantum level (operators). Making use of Wightman's definition
of invariance, we outline ambiguities linked to the notion of classical
fermionic Lagrangian. We then present the general constraints cast by these
transformations and their products on the propagator of the simplest among
coupled fermionic system, the one made with one fermion and its antifermion.
Last, we put in correspondence the propagation of C eigenstates (Majorana
fermions) and the criteria cast on their propagator by C and CP invariance.


title: Accretion-disc model spectra for dwarf-nova stars

abstract:
  Radiation from accretion discs in cataclysmic variable stars (CVs) provides
fundamental information about the properties of these close binary systems and
about the physics of accretion in general. The detailed diagnostics of
accretion disc structure can be achieved by including in its description all
the relevant heating and cooling physical mechanism, in particular the
convective energy transport that, although dominant at temperatures less than
about 10 000 K, is usually not taken into account when calculating spectra of
accretion discs. We constructed a radiative transfer code coupled with a code
determining the disc's hydrostatic vertical structure. We have obtained for the
first time model spectra of cold, convective accretion discs. As expected,
these spectra are mostly flat in the optical wavelengths with no contribution
from the UV, which in quiescence must be emitted by the white dwarf. The disc
structures obtained with our radiative-transfer code compare well with the
solutions of equations used to describe the dwarf-nova outburst cycle according
to the thermal-viscous disc instability model thus allowing the two to be
combined. Our code allows calculating the spectral evolution of dwarf nova
stars through their whole outburst cycle, providing a new tool for testing
models of accretion discs in cataclysmic variables. We show that convection
plays an important role in determining the vertical disc structure and
substantially affects emitted spectra when, as often the case, it is effective
at optical depths tau ~ 1. The emergent spectrum is independent of the
parameters of the convection model.(Abstract shortened)


title: Crossed Product of Cyclic Groups

abstract:
  All crossed products of two cyclic groups are explicitly described using
generators and relations. A necessary and sufficient condition for an extension
of a group by a group to be a cyclic group is given.


title: Conelike soap films spanning tetrahedra

abstract:
  In this paper we provide the first examples of non-flat soap films proven to
span tetrahedra. These are members of a continuous two parameter family of soap
films with tetrahedral boundaries. Of particular interest is a two parameter
subfamily where each spanning soap film has the property that two minimal
surfaces meet along an edge of the boundary at an angle greater than 120
degrees.


title:
Statistics of young starforming complexes in spiral galaxies using NIR
  photometry

abstract:
  All slightly extended sources were identified on deep K-band maps of 46
spiral galaxies reaching at least K=20.3 mag/arcsec2 at a signal-to-noise level
of 3. The galaxies had inclination angles <65 deg and linear resolutions <100
pc with seeing better than 1". The sample includes both barred and normal
spirals with a wide spread in types. We also analyzed J- and H-band colors for
4 galaxies for which such images were available. An apparent magnitude limit of
K = 19 mag was used for the sources analyzed in order to avoid marginal
detections. Furthermore, we derived the source distributions of magnitudes and
relative locations with respect to the spiral patterns.
  Almost 70% (15/22) of the grand-design spiral galaxies show significant
concentration of bright K-band knots in their arm regions corresponding to 30%
(15/46) of the full sample. Color-color diagrams for the 4 spirals with JHK
photometry suggest that a significant fraction of the diffuse sources found in
the arms are complexes of young stellar clusters with ages <10 Myr and reddened
with several magnitudes of visual extinction. The brightest knots reach an
absolute K-band magnitude Mk of -15.5 mag corresponding to stellar clusters or
complexes with total masses up to at least 10^5 Mo. Brightest magnitude and
number of knots correlate with the total absolute magnitude of the host galaxy.
More knots are seen in galaxies with high far-infrared flux and strong
two-armed spiral perturbations. The bright knots constitute up to a few percent
of the total K-band flux from their parent galaxy and account for a star
formation rate of ~1 Mo/yr for the brightest grand-design spiral galaxies.


title: Reopening the window on charged dark matter

abstract:
  We reexamine the limits on charged dark matter particles. We show that if
their mass and charge fall in the range 100(q_X/e)^2< m_X < 10^8(q_X/e) TeV,
then magnetic fields prevent particles in the halo from entering the galactic
disk, while those initially trapped inside are accelerated through the Fermi
mechanism and ejected within about 0.1-1 Gyrs. Consequently, previous
constraints on charged dark matter based on terrestrial non-observation are
invalid within that range. Further, we find that charged massive particles may
simultaneously solve several long-standing astrophysical problems, including
the underabundance of dwarf galaxies, the shallow density profiles in the cores
of the LSB galaxies, the absence of cooling flows in the cores of galaxy
clusters, and several others.


title: Minimal Spanning Tree graphs and power like scaling in FOREX networks

abstract:
  Correlation matrices of foreign exchange rate time series are investigated
for 60 world currencies. Minimal Spanning Tree (MST) graphs for the gold,
silver and platinum are presented. Inverse power like scaling is discussed for
these graphs as well as for four distinct currency groups (major, liquid, less
liquid and non-tradable). The worst scaling has been found for USD and related
currencies.


title:
Thermal noises and noise compensation in high-reflection multilayer
  coating

abstract:
  Thermal fluctuations of different origin in the substrate and in the coating
of optical mirrors produce phase noise in the reflected wave. This noise
determines the ultimate stabilization capability of high-Q cavities used as a
reference system. In particular this noise is significant in interferometric
laser gravitational wave antennas. It is shown that simple alteration of a
mirror multilayer coating may provide suppression of phase noise produced by
thermorefractive, thermoelastic, photothermal and thermoradiation induced
fluctuations in the coating.


title: On eigenfunctions corresponding to a small resurgent eigenvalue

abstract:
  This article is devoted to some foundational questions of resurgent analysis
as applied to the Schr\"odinger equation in one dimension.


title:
Field-Controlled Magnetic Order in the Quantum Spin-Ladder System
  (Hpip)2CuBr4

abstract:
  Neutron diffraction is used to investigate the field-induced,
antiferromagnetically ordered state in the two-leg spin-ladder material
(Hpip)2CuBr4. This "classical" phase, a consequence of weak interladder
coupling, is nevertheless highly unconventional: its properties are influenced
strongly by the spin Luttinger-liquid state of the ladder subunits. We
determine directly the order parameter (transverse magnetization), the ordering
temperature, the spin structure, and the critical exponents around the
transition. We introduce a minimal, microscopic model for the interladder
coupling and calculate the quantum fluctuation corrections to the mean-field
interaction.


title: Resurgent Analysis of the Witten Laplacian in One Dimension

abstract:
  The Witten Laplacian corresponding to a Morse function on the circle is
studied using methods of complex WKB and resurgent analysis. It is shown that
under certain assumptions the low-lying eigenvalues of the Witten Laplacian are
resurgent.


title: Scaling behavior of the disordered contact process

abstract:
  The one-dimensional contact process with weak to intermediate quenched
disorder in its transmission rates is investigated via quasi-stationary Monte
Carlo simulation. We address the contested questions of both the nature of
dynamical scaling, conventional or activated, as well as of universality of
critical exponents by employing a scaling analysis of the distribution of
lifetimes and the quasi-stationary density of infection. We find activated
scaling to be the appropriate description for all disorder strengths
considered. Critical exponents are disorder dependent and approach the values
expected for the limit of strong disorder as predicted by strong-disorder
renormalization group analysis of the process. However, even for the strongest
disorder under consideration no strong-disorder exponents are found.


title:
Single fiber transport by a fluid flow in a fracture with rough walls:
  influence of the fluid rheology

abstract:
  The possible transport of fibers by fluid flow in fractures is investigated
experimentally in transparent models using flexible polyester thread (mean
diameter $280 \mu\mathrm{m}$) and Newtonian and shear thinning fluids. In the
case of smooth parallel walls, fibers of finite length $\ell = 20-150
\mathrm{mm}$ move at a constant velocity of the order of the maximum fluid
velocity in the aperture. In contrast, for fibers lying initially at the inlet
side of the model and dragged by the flow inside it, the velocity increases
with the depth of penetration (this results from the lower velocity - and drag
- in the inlet part). In both cases, the friction of the fiber with the smooth
walls is weak. For rough self-affine walls and a continuous gradient of the
local mean aperture transverse to the flow, transport of the fibers by a water
flow is only possible in the region of larger aperture ($\bar{a} \gtrsim 1.1
\mathrm{mm}$) and is of "stop and go" type at low velocities. Time dependent
distorsions of the fiber are also often observed. When water is replaced by a
shear thinning polymer solution, the fibers move faster and continuously in
high aperture regions and their friction with the walls is reduced. Fiber
transport becomes also possible in narrower regions where irreversible pinning
occurred for water. In a third rough model with no global aperture gradient but
with rough walls and a channelization parallel to the mean flow, fiber
transport was only possible in shear-thinning flows and pinning and
entanglement effects were studied.


title: Quantum classification

abstract:
  Quantum classification is defined as the task of predicting the associated
class of an unknown quantum state drawn from an ensemble of pure states given a
finite number of copies of this state. By recasting the state discrimination
problem within the framework of Machine Learning (ML), we can use the notion of
learning reduction coming from classical ML to solve different variants of the
classification task, such as the weighted binary and the multiclass versions.


title:
Efficiency of the maximum partial likelihood estimator for nested case
  control sampling

abstract:
  In making inference on the relation between failure and exposure histories in
the Cox semiparametric model, the maximum partial likelihood estimator (MPLE)
of the finite dimensional odds parameter, and the Breslow estimator of the
baseline survival function, are known to achieve full efficiency when data is
available for all time on all cohort members, even when the covariates are time
dependent. When cohort sizes become too large for the collection of complete
data, sampling schemes such as nested case control sampling must be used and,
under various models, there exist estimators based on the same information as
the MPLE having smaller asymptotic variance. Though the MPLE is therefore not
efficient under sampling in general, it approaches efficiency in highly
stratified situations, or instances where the covariate values are increasingly
less dependent upon the past, when the covariate distribution, not depending on
the real parameter of interest, is unknown and there is no censoring. In
particular, in such situations, when using the nested case control sampling
design, both the MPLE and the Breslow estimator of the baseline survival
function achieve the information lower bound both in the distributional and the
minimax senses in the limit as the number of cohort members tends to infinity.


title: Recent results from parton cascade and microscopic transport

abstract:
  Parton cascade is a microscopic transport approach for the study of the
space-time evolution of the Quark-Gluon Plasma produced in relativistic heavy
ion collisions and its experimental manifestations. In the following, parton
cascade calculations on elliptic flow and thermalization will be discussed.
Dynamical evolution is shown to be important for the production of elliptic
flow including the scaling and the breaking of the scaling of elliptic flow.
The degree of thermalization is estimated using both an elastic parton cascade
and a radiative transport model. A longitudinal to transverse pressure ratio,
$P_L/P_T\approx 0.8$, is shown to be expected in the central cell in central
collisions. This provides information on viscous corrections to the ideal
hydrodynamical approach.


title:
Further explorations of Skyrme-Hartree-Fock-Bogoliubov mass formulas.
  IX: Constraint of pairing force to $^1S_0$ neutron-matter gap

abstract:
  In this latest of our series of Skyrme-HFB mass models, HFB-16, we introduce
the new feature of requiring that the contact pairing force reproduce at each
density the $^1S_0$ pairing gap of neutron matter as determined in microscopic
calculations with realistic nucleon-nucleon forces. We retain the earlier
constraints on the Skyrme force of reproducing the energy-density curve of
neutron matter, and of having an isoscalar effective mass of $0.8M$ in
symmetric infinite nuclear matter at the saturation density; we also keep the
recently adopted device of dropping Coulomb exchange. Furthermore, the
correction term for the spurious energy of collective motion has a form that is
known to favour fission barriers that are in good agreement with experiment.
Despite the extra constraints on the effective force, we have achieved a better
fit to the mass data than any other mean field model, the rms error on the 2149
measured masses of nuclei with $N$ and $Z \ge$ 8 having been reduced to 0.632
MeV; the improvement is particularly striking for the most neutron-rich nuclei.
Moreover, it turns out that even with no flexibility at all remaining for the
pairing force, the spectral pairing gaps that we find suggest that level
densities in good agreement with experiment should be obtained. This new force
is thus particularly well-suited for astrophysical applications, such as
stellar nucleosynthesis and neutron-star crusts.


title: The Stock Market as a Game: An Agent Based Approach to Trading in Stocks

abstract:
  Just as war is sometimes fallaciously represented as a zero sum game -- when
in fact war is a negative sum game - stock market trading, a positive sum game
over time, is often erroneously represented as a zero sum game. This is called
the "zero sum fallacy" -- the erroneous belief that one trader in a stock
market exchange can only improve their position provided some other trader's
position deteriorates. However, a positive sum game in absolute terms can be
recast as a zero sum game in relative terms. Similarly it appears that negative
sum games in absolute terms have been recast as zero sum games in relative
terms: otherwise, why would zero sum games be used to represent situations of
war? Such recasting may have heuristic or pedagogic interest but recasting must
be clearly explicited or risks generating confusion.
  Keywords: Game theory, stock trading and agent based AI.


title:
Point processes in arbitrary dimension from fermionic gases, random
  matrix theory, and number theory

abstract:
  It is well known that one can map certain properties of random matrices,
fermionic gases, and zeros of the Riemann zeta function to a unique point
process on the real line. Here we analytically provide exact generalizations of
such a point process in d-dimensional Euclidean space for any d, which are
special cases of determinantal processes. In particular, we obtain the
n-particle correlation functions for any n, which completely specify the point
processes. We also demonstrate that spin-polarized fermionic systems have these
same n-particle correlation functions in each dimension. The point processes
for any d are shown to be hyperuniform. The latter result implies that the pair
correlation function tends to unity for large pair distances with a decay rate
that is controlled by the power law r^[-(d+1)]. We graphically display one- and
two-dimensional realizations of the point processes in order to vividly reveal
their "repulsive" nature. Indeed, we show that the point processes can be
characterized by an effective "hard-core" diameter that grows like the square
root of d. The nearest-neighbor distribution functions for these point
processes are also evaluated and rigorously bounded. Among other results, this
analysis reveals that the probability of finding a large spherical cavity of
radius r in dimension d behaves like a Poisson point process but in dimension
d+1 for large r and finite d. We also show that as d increases, the point
process behaves effectively like a sphere packing with a coverage fraction of
space that is no denser than 1/2^d.


title: B Physics at LHC

abstract:
  Three experiments, among the LHC project, are getting ready to explore the b
quark flavour sector. While ATLAS and CMS are general purpose experiments,
where the study of B mesons is going to proceed in parallel with the Higgs
boson and supersymmetry searches, the LHCb experiment is devoted to B physics
studies. The key parameters entering the physics analyses and the performances
achieved in all the three experiments are presented. Given the large B physics
program foreseen in the LHC experiments, the studies reported in this paper
have been selected as those with higher likelihood to provide solid and
interesting new results on Standard Model validation and New Physics processes
search with early data.


title:
Serendipitous VLBI detection of rapid, large-amplitude, intraday
  variability in QSO 1156+295

abstract:
  We report a serendipitous detection of rapid, large amplitude flux density
variations in the highly core-dominated, flat-spectrum radio quasar 1156+295
during an observing session at the Very Long Baseline Array (VLBA). The source
was observed as a part of the MOJAVE survey programme with the VLBA at 15 GHz
on February 5, 2007. Large amplitude variability in the correlated flux
density, unexplainable in terms of the source structure, was first discovered
while processing the data, and later confirmed by calibrating the antenna gains
using 24 other sources observed in the experiment. The source shows variations
in the correlated flux density as high as 40% on a timescale of only 2.7 hours.
This places 1156+295 between the classical IDV sources and the so-called
intra-hour variables. The observed variability timescale and the modulation
index of 13% are consistent with interstellar scintillation by a nearby, highly
turbulent scattering screen. The large modulation index at 15 GHz implies a
scattering measure that is atypically high for a high galactic latitude source
such as 1156+295.


title: Neutrino masses in lepton number violating mSUGRA

abstract:
  In SUSY models which violate R-parity, there exist trilinear lepton number
violating (LNV) operators which can lead to neutrino masses. If these operators
are defined at the unification scale, the renormalization group flow becomes
important and generally leads to one neutrino mass much heavier than the
others. We study, in a minimal supergravity (mSUGRA) set-up with two trilinear
LNV operators and three charged lepton mixing angles, numerically how these
parameters may be arranged to be compatible with neutrino oscillation data, and
discuss some phenomenological observations.


title:
A stochastic model of anomalous heat transport: analytical solution of
  the steady state

abstract:
  We consider a one-dimensional harmonic crystal with conservative noise, in
contact with two stochastic Langevin heat baths at different temperatures. The
noise term consists of collisions between neighbouring oscillators that
exchange their momenta, with a rate $\gamma$. The stationary equations for the
covariance matrix are exactly solved in the thermodynamic limit ($N\to\infty$).
In particular, we derive an analytical expression for the temperature profile,
which turns out to be independent of $\gamma$. Moreover, we obtain an exact
expression for the leading term of the energy current, which scales as
$1/\sqrt{\gamma N}$. Our theoretical results are finally found to be consistent
with the numerical solutions of the covariance matrix for finite $N$.

categories: cond-mat.stat-mech math-ph math.MP nlin.CD


title: Intrinsically Linked Graphs in Projective Space

abstract:
  We examine graphs that contain a non-trivial link in every embedding into
real projective space, using a weaker notion of unlink than was used by Flapan,
et al. We call such graphs intrinsically linked in projective space. We fully
characterize such graphs with connectivity 0,1 and 2. We also show that only
one Petersen-family graph is intrinsically linked in projective space and prove
that K7 minus any two edges is also minor-minimal intrinsically linked. In all,
594 graphs are shown to be minor-minimal intrinsically linked in projective
space.


title: Tuning Mixing within a Droplet for Digital Microfluidics

abstract:
  The design of strategies to generate efficient mixing is crucial for a
variety of applications, particularly digital microfluidic devices that use
small "discrete" fluid volumes (droplets) as fluid carriers and microreactors.
In recent work, we have presented an approach for the generation and control of
mixing inside a translating spherical droplet. This was accomplished by
considering Stokes' flow within a droplet proceeding downstream to which we
have superimposed time dependent (sinusoidal) rotation. The mixing obtained is
the result of the stretching and folding of material lines which increase
exponentially the surface contact between reagents. The mixing strategy relies
on the generation of resonances between the steady and the unsteady part of the
flow, which is achieved by tuning the parameters of the periodic rotation. Such
resonances, in our system, offer the possibility of controlling both the
location and the size of the mixing region within the droplet, which may be
useful to manufacture inhomogeneous particles (such as Janus particles). While
the period and amplitude of the periodic rotation play a major role, it is
shown here by using a triangular function that the particular shape of the
rotation (as a function of time) has a minor influence. This finding
demonstrates the robustness of the proposed mixing strategy, a crucial point
for its experimental realization.


title:
Coupling between denaturation and chain conformations in DNA:
  stretching, bending, torsion and finite size effects

abstract:
  We develop further a statistical model coupling denaturation and chain
conformations in DNA (Palmeri J, Manghi M and Destainville N 2007 Phys. Rev.
Lett. 99 088103). Our Discrete Helical Wormlike Chain model takes explicitly
into account the three elastic degrees of freedom, namely stretching, bending
and torsion of the polymer. By integrating out these external variables, the
conformational entropy contributes to bubble nucleation (opening of
base-pairs), which sheds light on the DNA melting mechanism. Because the values
of monomer length, bending and torsional moduli differ significantly in dsDNA
and ssDNA, these effects are important. Moreover, we explore in this context
the role of an additional loop entropy and analyze finite-size effects in an
experimental context where polydA-polydT is clamped by two G-C strands, as well
as for free polymers.


title: Isometry groups of non-positively curved spaces: structure theory

abstract:
  We develop the structure theory of full isometry groups of locally compact
non-positively curved metric spaces. Amongst the discussed themes are de Rham
decompositions, normal subgroup structure and characterising properties of
symmetric spaces and Bruhat--Tits buildings. Applications to discrete groups
and further developments on non-positively curved lattices are exposed in a
companion paper: "Isometry groups of non-positively curved spaces: discrete
subgroups".


title: Agent Models of Political Interactions

abstract:
  Looks at state interactions from an agent based AI perspective to see state
interactions as an example of emergent intelligent behavior. Exposes basic
principles of game theory.


title:
Scattering of a two skyrmion configuration on potential holes of
  barriers in a model Landau-Lifshitz equation

abstract:
  The dynamics of a baby skyrmion configuration, in a model Landau-Lifshitz
equation, was studied in the presence of various potential obstructions. The
baby skyrmion configuration was constructed from two Q=1 hedgehog solutions to
the baby skyrme model in (2+1)dimensions. The potential obstructions were
created by introducing a new term into the Lagrangian which resulted in a
localised inhomogeneity in the potential terms' coefficient. In the barrier
system, the normal circular path was deformed as the skyrmions traversed the
barrier. During the same period, it was seen that the skyrmions sped up as they
went over the barrier. For critical values of the barrier height and width, the
skyrmions were no longer bound and were free to separate. In the case of a
potential hole, the baby skyrmions no longer formed a bound state and moved
asymptotically along the axis of the hole. It is shown how to modify the
definition of the angular momentum to include the effects of the obstructions,
so that it is conserved.


title: Stochastic Combinatorial Optimization under Probabilistic Constraints

abstract:
  In this paper, we present approximation algorithms for combinatorial
optimization problems under probabilistic constraints. Specifically, we focus
on stochastic variants of two important combinatorial optimization problems:
the k-center problem and the set cover problem, with uncertainty characterized
by a probability distribution over set of points or elements to be covered. We
consider these problems under adaptive and non-adaptive settings, and present
efficient approximation algorithms for the case when underlying distribution is
a product distribution. In contrast to the expected cost model prevalent in
stochastic optimization literature, our problem definitions support
restrictions on the probability distributions of the total costs, via
incorporating constraints that bound the probability with which the incurred
costs may exceed a given threshold.


title: The Semiotic Machine

abstract:
  A semiotic model of the user interface in human-computer interaction.
Algorithmic sign, semotics, algorithmic art.


title:
Observation of single-diffractive W production with CMS: a feasibility
  study

abstract:
  We present a study of single-diffractive $W$-boson production in $pp$
collisions at $\sqrt{s}=14$ TeV, $pp \to Xp$ with $X$ including a $W$ boson,
with the CMS detector. We discuss the feasibility of observing this process
with an integrated effective luminosity for single interactions of 100
pb$^{-1}$.


title: Versatile entropic measure of grey level inhomogeneity

abstract:
  The entropic measure for analysis of grey level inhomogeneity (GLI) is
proposed as a function of length scale. It allows us to quantify the
statistical dissimilarity of the actual macrostate and the maximizing entropy
of the reference one. The maximums (minimums) of the measure indicate those
scales at which higher (lower) average grey level inhomogeneity appears
compared to neighbour scales. Even a deeply hidden statistical grey level
periodicity can be detected by the equally distant minimums of the measure. The
striking effect of multiple intersecting curves (MIC) of the measure has been
revealed for pairs of simulated patterns, which differ in shades of grey or
symmetry properties, only. This indicates for a non-trivial dependence of the
GLI on length scale. In turn for evolving photosphere granulation patterns, the
stability in time of the first peak position has been found. Interestingly, at
initial steps of the evolution clearly dominates the third peak. This indicates
for a temporary grouping of granules at length scale that may belong to
mesogranulation phenomenon. This behaviour has similarities with that reported
by Consolini, Berrilli et al. (2003, 2005) for binarized granulation images of
a different data set.


title: Massive gravitons trapped inside a hypermonopole

abstract:
  We propose a regular classical field theory realisation of the
Dvali-Gabadadze-Porrati mechanism by considering our universe to be the
four-dimensional core of a seven dimensional 't Hooft-Polyakov hypermonopole.
We show the existence of metastable gravitons trapped in the core. Their mass
spectrum is discrete, positive definite, and computed for various values of the
field coupling constants: the resulting Newton gravity law is seven-dimensional
at small and large distances but can be made four-dimensional on intermediate
length scales. There is no need of a cosmological constant in the bulk, the
spacetime is asymptotically flat and of infinite volume in the
extra-dimensions. Confinement is achieved through the local positive curvature
of the extra-dimensions induced by the monopole-forming fields and for natural
values of the coupling constants of order unity.


title:
New Formulas and Methods for Interpolation, Numerical Differentiation
  and Numerical Integration

abstract:
  We present a new formula for divided difference and few new schemes of
divided difference tables in this paper. Through this, we derive new
interpolation, numerical differentiation and numerical integration formulas
with arbitrary order of accuracy for evanly and unevanly spaced data. First, we
study the new interpolation formula which generalizes both Newton's and
Lagrange's interpolation formula with the new divided difference table for
unevanly spaced points and using this; we derive other interpolation formulas,
in terms of differences for evanly spaced data. Second, we study two new
different methods of numerical differentiation for both evanly and unevanly
spaced points without differentiating the interpolating polynomials or the use
of operators. Third, we derive new numerical integration formulas using new
differentiation formulas and Taylor formula for both evanly and unevanly spaced
data. Basic computer algorithms for few new formulas are given. In Comparison
to former polynomial interpolation, numerical differentiation and numerical
integration formuals, these new formulas have some featured advantages for
approximating functional values, numerical derivatives of higher order and
approximate integral values for evanly and unevanly spaced data.


title:
The Bott cofiber sequence in deformation K-theory and simultaneous
  similarity in U(n)

abstract:
  We show that there is a homotopy cofiber sequence of spectra relating
Carlsson's deformation K-theory of a group G to its "deformation representation
ring," analogous to the Bott periodicity sequence relating connective K-theory
to ordinary homology. We then apply this to study simultaneous similarity of
unitary matrices.


title: Notes on Sela's work: Limit groups and Makanin-Razborov diagrams

abstract:
  This is the first in a planned series of papers giving an alternate approach
to Zlil Sela's work on the Tarski problems. The present paper is an exposition
of work of Kharlampovich-Myasnikov and Sela giving a parametrization of
Hom(G,F) where G is a finitely generated group and F is a non-abelian free
group.


title: Geometry of branes on supergroups

abstract:
  In this note we analyze the geometry of maximally symmetric boundary
conditions in Lie supergroup Wess-Zumino-Novikov-Witten models. We find that
generically the worldvolume of a brane is a twisted superconjugacy class, very
much like in the Lie group case. Whenever the brane is not completely
delocalized in the fermionic directions a new atypical class of branes arises.
We give an example of these new branes and show for type I supergroups and
trivial gluing conditions that they can be naturally associated with atypical
representations of the affine Lie superalgebra.


title: Dark spinors with torsion in cosmology

abstract:
  We solve one of the open problems in Einstein-Cartan theory, namely we find a
natural matter source whose spin angular momentum tensor is compatible with the
cosmological principle. We analyze the resulting evolution equations and find
that an epoch of accelerated expansion is an attractor. The torsion field
quickly decays in that period. Our results are interpreted in the context of
the standard model of cosmology.


title: Rank one isometries of buildings and quasi-morphisms of Kac-Moody groups

abstract:
  Given an irreducible non-spherical non-affine (possibly non-proper) building
$X$, we give sufficient conditions for a group $G < \Aut(X)$ to admit an
infinite-dimensional space of non-trivial quasi-morphisms. The result applies
to all irreducible (non-spherical and non-affine) Kac-Moody groups over
integral domains. In particular, we obtain finitely presented simple groups of
infinite commutator width, thereby answering a question of Valerii G. Bardakov
from the Kourovka notebook. Independently of these considerations, we also
include a discussion of rank one isometries of proper CAT(0) spaces from a
rigidity viewpoint. In an appendix, we show that any homogeneous quasi-morphism
of a locally compact group with integer values is continuous.


title: M2 signatures in psi(2S) radiative decays

abstract:
  The sensitivity of observables in radiative decays psi(2S) -> gamma chi_{1,2}
-> gamma gamma J/psi to quadrupole (M2) admixtures in the dominant electric
dipole (E1) transitions is explored. Emphasis is placed on distributions in a
single angle, and several examples are given.


title: The 2008 February superoutburst of V452 Cas

abstract:
  Observations of the 2008 February outburst of V452 Cas show that the profile,
duration and magnitude at maximum were very similar to the previous
superoutburst in 2007 September. Low-amplitude variations consistent with
previously observed superhumps were also seen.


title: Integration in algebraically closed valued fields

abstract:
  The first two steps of the construction of motivic integration in the
fundamental work of Hrushovski and Kazhdan have been presented in
arXiv:1006.2467v1. In this paper we present the final third step. As in
arXiv:1006.2467v1, we limit our attention to the theory of algebraically closed
valued fields of pure characteristic 0 expanded by a (VF, \Gamma)-generated
substructure S in the language L_{RV}. A canonical description of the kernel of
the lifting map is obtained.


abstract:
  Recurrence and explicit formulae for contractions (partial traces) of
antisymmetric and symmetric products of identical trace class operators are
derived. Contractions of product density operators of systems of identical
fermions and bosons are proved to be asymptotically equivalent to,
respectively, antisymmetric and symmetric products of density operators of a
single particle, multiplied by a normalization integer. The asymptotic
equivalence relation is defined in terms of the thermodynamic limit of
expectation values of observables in the states represented by given density
operators. For some weaker relation of asymptotic equivalence, concerning the
thermodynamic limit of expectation values of product observables, normalized
antisymmetric and symmetric products of density operators of a single particle
are shown to be equivalent to tensor products of density operators of a single
particle.
  This paper presents the results of a part of the author's thesis [W. Radzki,
"Kummer contractions of product density matrices of systems of $n$ fermions and
$n$ bosons" (Polish), MS thesis, Institute of Physics, Nicolaus Copernicus
University, Toru\'{n}, 1999].


title: Photoemission kinks and phonons in cuprates

abstract:
  One of the possible mechanisms of high Tc superconductivity is Cooper pairing
with the help of bosons, which change the slope of the electronic dispersion as
observed by photoemission. Giustino et al. calculated that in the high
temperature superconductor La1.85Sr0.15CuO4 crystal lattice vibrations
(phonons) should have a negligible effect on photoemission spectra and
concluded that phonons do not play an important role. We show that the
calculations employed by Giustino et al. fail to reproduce huge influence of
electron-phonon coupling on important phonons observed in experiments. Thus one
would expect these calculations to similarly fail in explaining the role of
electron-phonon coupling for the electronic dispersion.


title:
Goto Numbers of a Numerical Semigroup Ring and the Gorensteiness of
  Associated Graded Rings

abstract:
  The Goto number of a parameter ideal Q in a Noetherian local ring (R,m) is
the largest integer q such that Q : m^q is integral over Q. The Goto numbers of
the monomial parameter ideals of R = k[[x^{a_1}, x^{a_2},..., x_{a_{\nu}}]] are
characterized using the semigroup of R. This helps in computing them for
classes of numerical semigroup rings, as well as on a case-by-case basis. The
minimal Goto number of R and its connection to other invariants is explored.
Necessary and sufficient conditions for the associated graded rings of R and
R/x^{a_1}R to be Gorenstein are also given, again using the semigroup of R.


title: Average Continuous Control of Piecewise Deterministic Markov Processes

abstract:
  This paper deals with the long run average continuous control problem of
piecewise deterministic Markov processes (PDMP's) taking values in a general
Borel space and with compact action space depending on the state variable. The
control variable acts on the jump rate and transition measure of the PDMP, and
the running and boundary costs are assumed to be positive but not necessarily
bounded. Our first main result is to obtain an optimality equation for the long
run average cost in terms of a discrete-time optimality equation related to the
embedded Markov chain given by the post-jump location of the PDMP. Our second
main result guarantees the existence of a feedback measurable selector for the
discrete-time optimality equation by establishing a connection between this
equation and an integro-differential equation. Our final main result is to
obtain some sufficient conditions for the existence of a solution for a
discrete-time optimality inequality and an ordinary optimal feedback control
for the long run average cost using the so-called vanishing discount approach.


title:
Nonlinear Propagation of Crossing Electromagnetic Waves in Vacuum due to
  Photon-Photon Scattering

abstract:
  We review the theory for photon-photon scattering in vacuum, and some of the
proposals for its experimental search, including the results of our recent
works on the subject. We then describe a very simple and sensitive proposal of
an experiment and discuss how it can be used at the present (HERCULES) and the
future (ELI) ultrahigh power laser facilities either to find the first evidence
of photon-photon scattering in vacuum, or to significantly improve the current
experimental limits.


title:
Placing the Deep Impact Mission into Context: Two Decades of
  Observations of 9P/Tempel 1 from McDonald Observatory

abstract:
  We report on low-spectral resolution observations of comet 9P/Tempel 1 from
1983, 1989, 1994 and 2005 using the 2.7m Harlan J. Smith telescope of McDonald
Observatory. This comet was the target of NASA's Deep Impact mission and our
observations allowed us to characterize the comet prior to the impact. We found
that the comet showed a decrease in gas production from 1983 to 2005, with the
the decrease being different factors for different species. OH decreased by a
factor 2.7, NH by 1.7, CN by 1.6, C$_{3}$ by 1.8, CH by 1.4 and C$_{2}$ by 1.3.
Despite the decrease in overall gas production and these slightly different
decrease factors, we find that the gas production rates of OH, NH, C$_{3}$, CH
and C$_{2}$ ratioed to that of CN were constant over all of the apparitions. We
saw no change in the production rate ratios after the impact. We found that the
peak gas production occurred about two months prior to perihelion. Comet Tempel
1 is a "normal" comet.


title:
Harmonic functions and instanton moduli spaces on the multi-Taub--NUT
  space

abstract:
  Explicit construction of the basic SU(2) anti-instantons over the
multi-Taub--NUT geometry via the classical conformal rescaling method is
exhibited. These anti-instantons satisfiy the so-called weak holonomy condition
at infinity with respect to the trivial flat connection and decay rapidly. The
resulting unital energy anti-instantons have trivial holonomy at infinity. We
also fully describe their unframed moduli space and find that it is a five
dimensional space admitting a singular disk-fibration over R^3. On the way, we
work out in detail the twistor space of the multi-Taub--NUT geometry together
with its real structure and transform our anti-instantons into holomorphic
vector bundles over the twistor space. In this picture we are able to
demonstrate that our construction is complete in the sense that we have
constructed a full connected component of the moduli space of solutions of the
above type. We also prove that anti-instantons with arbitrary high integer
energy exist on the multi-Taub--NUT space.


title: Solvable Stochastic Dealer Models for Financial Markets

abstract:
  We introduce solvable stochastic dealer models, which can reproduce basic
empirical laws of financial markets such as the power law of price change.
Starting from the simplest model that is almost equivalent to a Poisson random
noise generator, the model becomes fairly realistic by adding only two effects,
the self-modulation of transaction intervals and a forecasting tendency, which
uses a moving average of the latest market price changes. Based on the present
microscopic model of markets, we find a quantitative relation with market
potential forces, which has recently been discovered in the study of market
price modeling based on random walks.


title: Bessel models for lowest weight representations of GSp(4,R)

abstract:
  We prove uniqueness and give precise criteria for existence of split and
non-split Bessel models for a class of lowest and highest weight
representations of the groups GSp(4,R) and Sp(4,R) including all holomorphic
and anti-holomorphic discrete series representations. Explicit formulas for the
resulting Bessel functions are obtained by solving systems of differential
equations. The formulas are applied to derive an integral representation for a
global $L$-function on GSp(4)xGL(2) involving a vector-valued Siegel modular
form of degree 2.


title:
The asymptotic behavior of degenerate oscillatory integrals in two
  dimensions

abstract:
  A theorem of Varchenko gives the order of decay of the leading term of the
asymptotic expansion of a degenerate oscillatory integral with real-analytic
phase in two dimensions. His theorem expresses this order of decay in a simple
geometric way in terms of its Newton polygon once one is in certain coordinate
systems called adapted coordinate systems.
  In this paper, we give explicit formulas that not only provide the order of
decay of the leading term, but also the coefficient of this term. There are
three rather different formulas corresponding to three different types of
Newton polygon. Analogous results for sublevel integrals are proven, as are
analogues for the more general case of smooth phase. The formulas require one
to be in certain "superadapted" coordinates. These are a type of adapted
coordinate system which we show exists for any smooth phase.


title: Colored Quaternion Dirac Particles of Charges 2/3 and -1/3

abstract:
  By starting with the simpliest expression of the first order linear wave
equation (Dirac's equation) and by confining the elements of the coefficients
(matrices) to the quaternions, it is shown that the association of the
imaginary bases of the quaternions with three "colors" and their conserved
currents results in quasi-particles with charges of 2/3 and -1/3 with a minimum
of assumptions. It is shown how color neutral particles are required by Q
covariance, first discussed by Finkelstein, et. al. in 1963.


title:
An Alternative Path to the Boundary - the CFT as the Fourier Space of
  AdS

abstract:
  In this paper we shed new light on the AdS/CFT duality by interpreting the
CFT as the Fourier space of AdS. We make use of well known integral geometry
techniques to derive the Fourier transformation of a function defined on the
AdS hyperboloid. We show that the Fourier Transformation of a function on the
hyperboloid is a function defined on the boundary. We find that the Green's
functions from the literature are actually the Fourier weights (i.e. plane wave
solutions) of the transformation and that the boundary values of fields
appearing in the correspondence are the Fourier components of the
transformation. One is thus left to interpret the CFT as the quantized version
of a classical theory in AdS and the dual operator as the Fourier coefficients.
Group theoretic considerations are discussed in relation to the transformation
and its potential use in constructing QCD like theories. In addition, we
consider possible implications involving understanding the dual of AdS black
holes.


title: Quantum Hall Effect in Quantum Electrodynamics

abstract:
  We consider the quantum Hall effect in quantum electrodynamics and find a
deviation from the quantum mechanical prediction for the Hall conductivity due
to radiative antiscreening of electric charge in an external magnetic field. A
weak universal dependence of the von Klitzing constant on the magnetic field
strength, which can possibly be observed in a dedicated experiment, is
predicted.


title:
Toy model for plasmonic metamaterial resonances coupled to two-level
  system gain

abstract:
  We propose, solve, and discuss a simple model for a metamaterial
incorporating optical gain: A single bosonic resonance is coupled to a
fermionic (inverted) two-level-system resonance via local-field interactions.
For given steady-state inversion, this model can be solved analytically,
revealing a rich variety of (Fano) absorption/gain lineshapes. We also give an
analytic expression for the fixed inversion resulting from gain pinning under
steady-state conditions. Furthermore, the dynamic response of the 'lasing
SPASER', i.e., its relaxation oscillations, can be obtained by simple numerical
calculations within the same model. As a result, this toy model can be viewed
as the near-field-optical counterpart of the usual LASER rate equations.


title: Pattern avoidance in binary trees

abstract:
  This paper considers the enumeration of trees avoiding a contiguous pattern.
We provide an algorithm for computing the generating function that counts
n-leaf binary trees avoiding a given binary tree pattern t. Equipped with this
counting mechanism, we study the analogue of Wilf equivalence in which two tree
patterns are equivalent if the respective n-leaf trees that avoid them are
equinumerous. We investigate the equivalence classes combinatorially. Toward
establishing bijective proofs of tree pattern equivalence, we develop a general
method of restructuring trees that conjecturally succeeds to produce an
explicit bijection for each pair of equivalent tree patterns.


title: On Q-conic bundles, III

abstract:
  A Q-conic bundle germ is a proper morphism from a threefold with only
terminal singularities to the germ $(Z \ni o)$ of a normal surface such that
fibers are connected and the anti-canonical divisor is relatively ample.
Building upon our previous paper [math/0603736], we prove the existence of a Du
Val anti-canonical member under the assumption that the central fiber is
irreducible.


title: Principal Graphs and Manifolds

abstract:
  In many physical, statistical, biological and other investigations it is
desirable to approximate a system of points by objects of lower dimension
and/or complexity. For this purpose, Karl Pearson invented principal component
analysis in 1901 and found 'lines and planes of closest fit to system of
points'. The famous k-means algorithm solves the approximation problem too, but
by finite sets instead of lines and planes. This chapter gives a brief
practical introduction into the methods of construction of general principal
objects, i.e. objects embedded in the 'middle' of the multidimensional data
set. As a basis, the unifying framework of mean squared distance approximation
of finite datasets is selected. Principal graphs and manifolds are constructed
as generalisations of principal components and k-means principal points. For
this purpose, the family of expectation/maximisation algorithms with nearest
generalisations is presented. Construction of principal graphs with controlled
complexity is based on the graph grammar approach.


title: Semi-Leptonic b-decay at Intermediate Recoil

abstract:
  We compute the O(\alpha_s^2) corrections to the differential rate of the
semileptonic decay b -> clv at the "intermediate recoil" point, where the
c-quark mass and the invariant mass of the leptons are equal. The calculation
is based on an expansion around two opposite limits of the quark masses
m_{b,c}: m_c ~ m_b and m_c << m_b. The former case was previously studied; we
correct and extend that result. The latter case is new. The smooth matching of
both expansions provides a check of both. We clarify the discrepancy between
the recent determinations of the full NNLO QCD correction to the semileptonic b
-> c rate, and its earlier estimate.


title: From Data to the p-Adic or Ultrametric Model

abstract:
  We model anomaly and change in data by embedding the data in an ultrametric
space. Taking our initial data as cross-tabulation counts (or other input data
formats), Correspondence Analysis allows us to endow the information space with
a Euclidean metric. We then model anomaly or change by an induced ultrametric.
The induced ultrametric that we are particularly interested in takes a
sequential - e.g. temporal - ordering of the data into account. We apply this
work to the flow of narrative expressed in the film script of the Casablanca
movie; and to the evolution between 1988 and 2004 of the Colombian social
conflict and violence.


title: Gluing endo-permutation modules

abstract:
  In this paper, I show that if $p$ is an odd prime, and if $P$ is a finite
$p$-group, then there exists an exact sequence of abelian groups $$0\to T(P)\to
D(P)\to\lproj{P}\to H^1\big(\apdeux(P),\Z\big)^{(P)},$$ where $D(P)$ is the
Dade group of $P$ and $T(P)$ is the subgroup of endo-trivial modules. Here
$\lproj{P}$ is the group of sequences of compatible elements in the Dade groups
$D\big(N_P(Q)/Q\big)$ for non trivial subgroups $Q$ of $P$. The poset
$\apdeux(P)$ is the set of elementary abelian subgroups of rank at least 2 of
$P$, ordered by inclusion. The group $H^1\big(\apdeux(P),\Z\big)^{(P)}$ is the
subgroup of $H^1\big(\apdeux(P),\Z\big)$ consisting of classes of $P$-invariant
1-cocycles. Here $\lproj{P}$ is the group of sequences of compatible elements
in the Dade groups $D\big(N_P(Q)/Q\big)$ for non trivial subgroups $Q$ of $P$.
The poset $\apdeux(P)$ is the set of elementary abelian subgroups of rank at
least 2 of $P$, ordered by inclusion. The group
$H^1\big(\apdeux(P),\Z\big)^{(P)}$ is the subgroup of
$H^1\big(\apdeux(P),\Z\big)$ consisting of classes of $P$-invariant 1-cocycles.
A key result to prove that the above sequence is exact is a characterization of
elements of $2D(P)$ by sequences of integers, indexed by sections $(T,S)$ of
$P$ such that $T/S\cong (\Z/p\Z)^2$, fulfilling certain conditions associated
to subquotients of $P$ which are either elementary abelian of rank~3, or
extraspecial of order $p^3$ and exponent $p$.


title: Interaction Grammars

abstract:
  Interaction Grammar (IG) is a grammatical formalism based on the notion of
polarity. Polarities express the resource sensitivity of natural languages by
modelling the distinction between saturated and unsaturated syntactic
structures. Syntactic composition is represented as a chemical reaction guided
by the saturation of polarities. It is expressed in a model-theoretic framework
where grammars are constraint systems using the notion of tree description and
parsing appears as a process of building tree description models satisfying
criteria of saturation and minimality.


title:
Near-Infrared Photometry of Four Stellar Clusters in the Small
  Magellanic Cloud

abstract:
  We present high-quality J, H and K photometry of four Small Magellanic Cloud
stellar clusters with intermediate ages in the 1-7 Gyr range (namely NGC 339,
361, 416 and 419) . We obtained deep Color-Magnitude Diagrams to study the
evolved sequences and providing a detailed census of the Red Giant Branch
(RGB), Asymptotic Giant Branch (AGB) and Carbon star populations in each
cluster and their contribution to the total cluster light. We find that in the
5-7 Gyr old clusters AGB stars account for ~6 % of the total light in K-band,
Carbon stars are lacking and RGB stars account for ~45 % of the total
bolometric luminosity. These empirical findings are in good agreement with the
theoretical predictions. Finally, we derived photometric metallicities computed
by using the properties of the RGB and finding an iron content of [Fe/H]=-1.18,
-1.08, -0.99 and -0.96 dex for NGC 339, 361, 416 and 419 respectively.


title: Renormalised nonequilibrium quantum field theory: scalar fields

abstract:
  We discuss the renormalisation of the initial value problem in quantum field
theory using the two-particle irreducible (2PI) effective action formalism. The
nonequilibrium dynamics is renormalised by counterterms determined in
equilibrium. We emphasize the importance of the appropriate choice of initial
conditions and go beyond the Gaussian initial density operator by defining
self-consistent initial conditions. We study the corresponding time evolution
and present a numerical example which supports the existence of a continuum
limit for this type of initial conditions.


title: Dark Matter Caustics

abstract:
  Caustics are a generic feature of the nonlinear growth of structure in the
dark matter distribution. If the dark matter were absolutely cold, its mass
density would diverge at caustics, and the integrated annihilation probability
would also diverge for individual particles participating in them. For
realistic dark matter candidates, this behaviour is regularised by small but
non-zero initial thermal velocities. We present a mathematical treatment of
evolution from Hot, Warm or Cold Dark Matter initial conditions which can be
directly implemented in cosmological N-body codes. It allows the identification
of caustics and the estimation of their annihilation radiation in fully general
simulations of structure formation.


title:
Implication of the HyperCP boson $X^0$ (214 MeV) in the flavour changing
  neutral current processes

abstract:
  We analyze the inclusive $b(c) \to s(u) \mu^+ \mu^-$ and the exclusive
$B(D^+) \to K(\pi^+) \mu^+ \mu^-$ flavour changing neutral current decays in
the light of HyperCP boson $X^0$ of mass 214 MeV recently observed in the
hyperon decay $\Sigma^+ \to p \mu^+ \mu^-$. Using the branching ratio data of
the above inclusive and exclusive decays, we obtain constraints on $g_1 (h_1)$
and $g_2 (h_2)$, the scalar and pseudo-scalar coupling constants of the
$b-s-X^0 (c-u-X^0)$ vertices.


title:
Density functional study of BaNi$_2$As$_2$: Electronic structure,
  phonons and electron-phonon superconductivity

abstract:
  We investigate the properties of BaNi$_2$As$_2$ using first principles
calculations. The band structure has a similar shape to that of the
BaFe$_2$As$_2$, and in particular shows a pseudogap between a manifold of six
heavy $d$ electron bands and four lighter $d$ bands, i.e. at an electron count
of six $d$ electrons per Ni. However, unlike BaFe$_2$As$_2$, where the Fermi
energy occurs at the bottom of the pseudogap, the two additional electrons per
Ni in the Ni compound place the Fermi energy in the upper manifold. Thus
BaNi$_2$As$_2$ has large Fermi surfaces very distinct from BaFe$_2$As$_2$.
Results for the phonon spectrum and electron-phonon coupling are consistent
with a classification of this material as a conventional phonon mediated
superconductor although spin fluctuations and nearness to magnetism may be
anticipated based on the value of $N(E_F)$.


title: Direct limits, multiresolution analyses, and wavelets

abstract:
  A multiresolution analysis for a Hilbert space realizes the Hilbert space as
the direct limit of an increasing sequence of closed subspaces. In a previous
paper, we showed how, conversely, direct limits could be used to construct
Hilbert spaces which have multiresolution analyses with desired properties. In
this paper, we use direct limits, and in particular the universal property
which characterizes them, to construct wavelet bases in a variety of concrete
Hilbert spaces of functions. Our results apply to the classical situation
involving dilation matrices on $L^2(\R^n)$, the wavelets on fractals studied by
Dutkay and Jorgensen, and Hilbert spaces of functions on solenoids.


title:
Unidirectional decomposition method for obtaining exact localized waves
  solutions totally free of backward components

abstract:
  In this paper we use a unidirectional decomposition capable of furnishing
localized wave pulses, with luminal and superluminal peak velocities, in exact
form and totally free of backward components, which have been a chronic problem
for such wave solutions. This decomposition is powerful enough for yielding not
only ideal nondiffracting pulses but also their finite energy versions still in
exact analytical closed form. Another advantage of the present approach is
that, since the backward spectral components are absent, the frequency spectra
of the pulses do not need to possess ultra-widebands, as it is required by the
usual localized waves (LWs) solutions obtained by other methods. Finally, the
present results bring the LW theory nearer to the real experimental
possibilities of usual laboratories.


title: The 5-local homotopy of $eo_4$

abstract:
  We compute the 5-local cohomology of a 5-local analogue of the Weierstrass
Hopf algebroid used to compute $tmf$ homology. We compute the Adams-Novikov
differentials in the cohomology, giving the homotopy, V(0)-homology, and
V(1)-homology of the putative spectrum $eo_4$. We also link this computation to
the homotopy of the higher real $K$-theory spectrum $EO_4$.


title:
MOST satellite photometry of stars in the M67 field: Eclipsing binaries,
  blue stragglers and delta-Scuti variables

abstract:
  We present two series of MOST (Microvariability & Oscillations of STars)
space-based photometry, covering nearly continuously 10 days in 2004 and 30
days in 2007, of selected variable stars in the upper Main Sequence of the old
open cluster M67. New high-precision light curves were obtained for the
blue-straggler binary/triple systems AH Cnc, ES Cnc and EV Cnc. The precision
and phase coverage of ES Cnc and EV Cnc is by far superior to any previous
observations. The light curve of ES Cnc is modelled in detail, assuming two
dark photospheric spots and Roche geometry. An analysis of the light curve of
AH Cnc indicates a low mass ratio (q about 0.13) and a high inclination angle
for this system. Two new long-period eclipsing binaries, GSC 814-323 and
HD75638 (non-members of M67) were discovered. We also present ground-based DDO
spectroscopy of ES Cnc and of the newly found eclipsing binaries. Especially
interesting is HD75638, a member of a visual binary, which must itself be a
triple or a higher-multiplicity system. New light curves of two delta Scuti
pulsators, EX Cnc and EW Cnc, have been analyzed leading to detection of 26 and
8 pulsation frequencies of high temporal stability.


title:
The Sigma Profile: A Formal Tool to Study Organization and its Evolution
  at Multiple Scales

abstract:
  The $\sigma$ profile is presented as a tool to analyze the organization of
systems at different scales, and how this organization changes in time.
Describing structures at different scales as goal-oriented agents, one can
define $\sigma \in [0,1]$ ("satisfaction") as the degree to which the goals of
each agent at each scale have been met. $\sigma$ reflects the organization
degree at that scale. The $\sigma$ profile of a system shows the satisfaction
at different scales, with the possibility to study their dependencies and
evolution. It can also be used to extend game theoretic models. A general
tendency on the evolution of complexity and cooperation naturally follows from
the $\sigma$ profile. Experiments on a virtual ecosystem are used as
illustration.


title:
Metastable superfluidity of repulsive fermionic atoms in optical
  lattices

abstract:
  In the fermionic Hubbard model, doubly occupied states have an exponentially
large lifetime for strong repulsive interactions U. We show that this property
can be used to prepare a metastable s-wave superfluid state for fermionic atoms
in optical lattices described by a large-U Hubbard model. When an initial
band-insulating state is expanded, the doubly occupied sites Bose condense. A
mapping to the ferromagnetic Heisenberg model in an external field allows for a
reliable solution of the problem. Nearest-neighbor repulsion and pair hopping
are important in stabilizing superfluidity.


title: The Void Abundance with Non-Gaussian Primordial Perturbations

abstract:
  We use a Press-Schechter-like calculation to study how the abundance of voids
changes in models with non-Gaussian initial conditions. While a positive
skewness increases the cluster abundance, a negative skewness does the same for
the void abundance. We determine the dependence of the void abundance on the
non-Gaussianity parameter fnl for the local-model bispectrum-which approximates
the bispectrum in some multi-field inflation models-and for the equilateral
bispectrum, which approximates the bispectrum in e.g. string-inspired DBI
models of inflation. We show that the void abundance in large-scale-structure
surveys currently being considered should probe values as small as fnl < 10 and
fnl^eq < 30, over distance scales ~10 Mpc.


title: The chiral ring of AdS3/CFT2 and the attractor mechanism

abstract:
  We study the moduli dependence of the chiral ring in N = (4,4) superconformal
field theories, with special emphasis on those CFTs that are dual to type IIB
string theory on AdS3xS3xX4. The chiral primary operators are sections of
vector bundles, whose connection describes the operator mixing under motion on
the moduli space. This connection can be exactly computed using the constraints
from N = (4,4) supersymmetry. Its curvature can be determined using the tt*
equations, for which we give a derivation in the physical theory which does not
rely on the topological twisting. We show that for N = (4,4) theories the
chiral ring is covariantly constant over the moduli space, a fact which can be
seen as a non-renormalization theorem for the three-point functions of chiral
primaries in AdS3/CFT2. From the spacetime point of view our analysis has the
following applications. First, in the case of a D1/D5 black string, we can see
the matching of the attractor flow in supergravity to RG-flow in the boundary
field theory perturbed by irrelevant operators, to first order away from the
fixed point. Second, under spectral flow the chiral primaries become the Ramond
ground states of the CFT. These ground states represent the microstates of a
small black hole in five dimensions consisting of a D1/D5 bound state. The
connection that we compute can be considered as an example of Berry's phase for
the internal microstates of a supersymmetric black hole.


title:
The properties of the host galaxy and the immediate environment of GRB
  980425 / SN 1998bw from the multi-wavelength spectral energy distribution

abstract:
  We present an analysis of the spectral energy distribution (SED) of the
galaxy ESO 184-G82, the host of the closest known long gamma-ray burst (GRB)
980425 and its associated supernova (SN) 1998bw. We use our observations
obtained at the Australia Telescope Compact Array (the third >3 sigma radio
detection of a GRB host) as well as archival infrared and ultraviolet (UV)
observations to estimate its star formation state. We find that ESO 184-G82 has
a UV star formation rate (SFR) and stellar mass consistent with the population
of cosmological GRB hosts and of local dwarf galaxies. However, it has a higher
specific SFR (per unit stellar mass) than luminous spiral galaxies. The mass of
ESO 184-G82 is dominated by an older stellar population in contrast to the
majority of GRB hosts. The Wolf-Rayet region ~800 pc from the SN site
experienced a starburst episode during which the majority of its stellar
population was built up. Unlike that of the entire galaxy, its SED is similar
to those of cosmological submillimeter/radio-bright GRB hosts with hot dust
content. These findings add to the picture that in general, the environments of
GRBs on 1-3 kpc scales are associated with high specific SFR and hot dust.


title: What Makes an Accretion-Powered Millisecond Pulsar?

abstract:
  We investigate the dependence of pulse amplitudes of accreting millisecond
pulsars on the masses of the neutron stars. Because the pulsation amplitudes
are suppressed as the neutron stars become more massive, the probability of
detection of pulsations decreases in systems that have been accreting for a
long time. However, the probability of detectable pulsations is higher in
transient systems where the mass accretion is sporadic and the neutron star is
likely to have a low mass. We propose this mechanism as the explanation of the
small number of millisecond X-ray pulsars found to date, as well as their
emergence as fast pulsars mostly in transient, low-Mdot systems. This mechanism
can also quantitatively explain the lack of pulsars in the majority of LMXBs.


title:
A New Class of Luminous Transients and A First Census of Their Massive
  Stellar Progenitors

abstract:
  The progenitors of SN 2008S and the 2008 transient in NGC300 were
dust-enshrouded, with extremely red mid-infrared (MIR) colors and relatively
low luminosities. The transients were optically faint (-13 < M_V < -15)
compared to normal core-collapse supernovae (SNe), and their spectra exhibited
narrow emission lines. These events are unique among transient-progenitor pairs
and hence constitute a new class. Whether they are true SNe or bright
massive-star eruptions, we argue that their rate is ~20% of the SN rate. This
fact is remarkable in light of the observation that a very small fraction of
all massive stars have the MIR colors of the SN 2008S and NGC300 progenitors,
as we show using MIR and optical luminosity, color, and variability properties
of massive stars in M33. We find that the fraction of massive stars with colors
consistent with these progenitors is 1/10000. In fact, only < 10 similar
objects exist in M33 - all of which lie at the luminous red extremum of the AGB
sequence. That these transients are relatively common with respect to SNe,
while their progenitors are rare compared to the massive star population,
implies that the dust-enshrouded phase is a short-lived phase in the lives of
many massive stars. This shrouded epoch can occur only in the last ~10^4 yr
before explosion, be it death or merely eruption. We discuss the implications
of this finding for the evolution and census of ``low-mass'' massive stars
(8-12 Msun), and we connect it with theoretical discussions of electron-capture
SNe and the explosive birth of white dwarfs. A systematic census with (warm)
Spitzer of galaxies in the local universe for analogous progenitors would
significantly improve our knowledge of this channel to massive stellar
explosions, and potentially to others with obscured progenitors. (Abridged)


title:
Origin and evolution of moving groups I. Characterization in the
  observational kinematic-age-metallicity space

abstract:
  Context. Recent studies have suggested that moving groups have a dynamic or
"resonant" origin. Under this hypothesis, these kinematic structures become a
powerful tool for studying the large-scale structure and dynamics of the Milky
Way. Aims. We aim to characterize these structures in the U-V-age-[Fe/H] space
and establish observational constraints that will allow us to study their
origin and evolution. Methods. We apply multiscale techniques -wavelet
denoising (WD)- to an extensive compendium of more than 24000 stars in the
solar neighbourhood with the best available astrometric, photometric and
spectroscopic data. Results. We confirm that the dominant structures in the U-V
plane are the branches of Sirius, Coma Berenices, Hyades-Pleiades and Hercules,
which are nearly equidistant in this kinematic plane and show a negative slope.
The abrupt drops in the velocity distribution are characterized. We find a
certain dependence of these kinematic structures on Galactic position with a
significant change of contrast among substructures inside the branches. A large
spread of ages is observed for all branches. The Hercules branch is detected in
all subsamples with ages older than ~ 2 Gyr and the set of the other three
branches is well established for stars > 400 Myr. The age-metallicity relation
of each branch is examined and the relation between kinematics and metallicity
is studied. Conclusions. Not all of these observational constraints are
successfully explained by the recent models proposed for the formation of such
kinematic structures. Simulations incorporating stellar ages and metallicities
are essential for future studies. The comparison of the observed and simulated
distributions obtained by WD will provide a physical interpretation of the
existence of the branches in terms of local or large-scale dynamics. [Abridged]


title:
First-Order Transition to Incommensurate Phase with Broken Lattice
  Rotation Symmetry in Frustrated Heisenberg Model

abstract:
  We study a finite-temperature phase transition in the two-dimensional
classical Heisenberg model on a triangular lattice with a ferromagnetic
nearest-neighbor interaction $J_1$ and an antiferromagnetic
third-nearest-neighbor interaction $J_3$ using a Monte Carlo method. Apart from
a trivial degeneracy corresponding to O(3) spin rotations,the ground state for
$J_3 \neq 0$ has a threefold degeneracy corresponding to 120 degree lattice
rotations. We find that this model exhibits a first-order phase transition with
the breaking of the threefold symmetry when the interaction ratio is
$J_3/J_1=-3$.


title: Formation and evolution of disk galaxies

abstract:
  Global star formation is the key to understanding galaxy disk formation. This
in turn depends on gravitational instability of disks and continuing gas
accretion as well as minor merging. A key component is feedback from
supernovae. Primary observational constraints on disk galaxy formation and
evolution include the Schmidt-Kennicutt law, the Tully-Fisher relation and the
galaxy luminosity function. I will review how theory confronts phenomenology,
and discuss future prospects for refining our understanding of disk formation.


title: Lobby index in networks

abstract:
  We propose a new node centrality measure in networks, the lobby index, which
is inspired by Hirsch's h-index. It is shown that in scale free networks the
l-index has power tail with exponent square of the exponent of the degree
distribution one. Properties of the l-index and extensions are discussed.


title: Anisotropic AGN Outflows Filling The Cosmological Volume

abstract:
  We simulate anisotropic outflows of AGN, and investigate the large-scale
impact of the cosmological population of AGN outflows over the Hubble time by
performing N-body LambdaCDM simulations. Using the observed quasar luminosity
function to get the redshift and luminosity distribution, and analytical models
for the outflow expansion, AGNs are allowed to evolve in a cosmological volume.
By the present epoch, 13 - 25% of the total volume is found to be pervaded by
AGN outflows, with 10^{-9} G magnetic field.


title:
Femtoscopy in Relativistic Heavy Ion Collisions and its Relation to Bulk
  Properties of QCD Matter

abstract:
  Using a viscous hydrodynamic model coupled to a hadronic cascade code,
numerous features of the dynamics and equilibrium properties are explored for
their impact on femtoscopic measurements. The equation of state, viscous
parameters and initial conditions are investigated. We find that femtoscopy is
affected by numerous model features at the 10% level, and that by including
features and adjusting unknown parameters, one can explain experimental source
size measurements to better than 10%.


title: Lectures on Landau Hydrodynamics

abstract:
  Landau hydrodynamics is a plausible description for the evolution of the
dense hot matter produced in high-energy heavy-ion collisions. We review the
formulation of Landau hydrodynamics to pave the way for its application in
high-energy heavy-ion collisions. It is found that Landau's rapidity
distribution needs to be modified to provide a better quantitative description.
In particular, the rapidity distribution in the center-of-mass system should be
more appropriately given as dN/dy \exp{\sqrt{y_b^2-y^2}}, where
y_b=\ln{\sqrt{s_NN}/m_p} is the beam nucleon rapidity, instead of Landau's
original result of dN/dy({Landau}) \exp{\sqrt{L^2-y^2}} where
L=\ln{\sqrt{s_NN}/2m_p}. The modified distribution is compared with the Landau
distribution and experimental data. It is found that the modified distribution
agrees better with experimental $dN/dy$ data than the Landau distribution and
it differs only slightly from the Landau Gaussian distribution
dN/dy(Landau-Gaussian) \exp{-y^2/2L}. Past successes of the Gaussian
distribution in explaining experimental rapidity data arises, not because it is
an approximation of the original Landau distribution, but because it is in fact
a close representation of the modified distribution.


title: Formation of quark phases in compact stars and SN explosion

abstract:
  We describe possible scenarios of quark deconfinement in compact stars and we
analyze their astrophysical implications. The quark deconfinement process can
proceed rapidly, as a strong deflagration, releasing a huge amount of energy in
a short time and generating an extra neutrino burst. If energy is transferred
efficiently to the surface, like e.g. in the presence of convective
instabilities, this burst could contribute to revitalize a partially failed SN
explosion. We discuss how the neutrino observations from SN1987A would fit in
this scenario. Finally, we focus on the fate of massive and rapidly rotating
progenitors, discussing possible time separations between the moment of the
core collapse and the moment of quark deconfinement. This mechanism can be at
the basis of the interpretation of gamma ray bursts in which lines associated
with heavy elements are present in the spectrum.


title: Complexity of comparison of influence of players in simple games

abstract:
  Coalitional voting games appear in different forms in multi-agent systems,
social choice and threshold logic. In this paper, the complexity of comparison
of influence between players in coalitional voting games is characterized. The
possible representations of simple games considered are simple games
represented by winning coalitions, minimal winning coalitions, weighted voting
game or a multiple weighted voting game. The influence of players is gauged
from the viewpoint of basic player types, desirability relations and classical
power indices such as Shapley-Shubik index, Banzhaf index, Holler index,
Deegan-Packel index and Chow parameters. Among other results, it is shown that
for a simple game represented by minimal winning coalitions, although it is
easy to verify whether a player has zero or one voting power, computing the
Banzhaf value of the player is #P-complete. Moreover, it is proved that
multiple weighted voting games are the only representations for which it is
NP-hard to verify whether the game is linear or not. For a simple game with a
set W^m of minimal winning coalitions and n players, a O(n.|W^m|+(n^2)log(n))
algorithm is presented which returns `no' if the game is non-linear and returns
the strict desirability ordering otherwise. The complexity of transforming
simple games into compact representations is also examined.


title: Understanding the Optical Potential in HBT Interferometry

abstract:
  The validity of using a pion optical potential to incorporate the effects of
final state interactions on HBT interferometry is investigated. We find that if
the optical potential is real, the standard formalism is modified as previously
described in the literature. However, if the optical potential is complex, a
new term involving pion emission from eliminated states must be included. The
size of such effects in previous work by Cramer and Miller is assessed.


title:
Infrared Imaging of SDSS Quasars: Implications for the Quasar K
  correction

abstract:
  We have imaged 45 quasars from the Sloan Digital Sky Survey (SDSS) with
redshifts 1.85 < z < 4.26 in JHKs with the KPNO SQIID imager. By combining
these data with optical magnitudes from the SDSS we have computed the restframe
optical spectral indices of this sample and investigate their relation to
quasar redshift. We find a mean spectral index of <alpha_o> = -0.55+/-0.42 with
a large spread in values. We also find possible evolution of the form alpha_o =
(0.148+/-0.068)z - (0.964+/-0.200)$ in the luminosity range -28.0 < M_i <
-26.5. Such evolution suggests changes in the accretion process in quasars with
time and is shown to have an effect on computed quasar luminosity functions.


title: The first-mover advantage in scientific publication

abstract:
  Mathematical models of the scientific citation process predict a strong
"first-mover" effect under which the first papers in a field will, essentially
regardless of content, receive citations at a rate enormously higher than
papers published later. Moreover papers are expected to retain this advantage
in perpetuity -- they should receive more citations indefinitely, no matter how
many other papers are published after them. We test this conjecture against
data from a selection of fields and in several cases find a first-mover effect
of a magnitude similar to that predicted by the theory. Were we wearing our
cynical hat today, we might say that the scientist who wants to become famous
is better off -- by a wide margin -- writing a modest paper in next year's
hottest field than an outstanding paper in this year's. On the other hand,
there are some papers, albeit only a small fraction, that buck the trend and
attract significantly more citations than theory predicts despite having
relatively late publication dates. We suggest that papers of this kind, though
they often receive comparatively few citations overall, are probably worthy of
our attention.


title:
Dynamic phase transition in the two-dimensional kinetic Ising model in
  an oscillating field: Universality with respect to the stochastic dynamic

abstract:
  We study the dynamical response of a two-dimensional Ising model subject to a
square-wave oscillating external field. In contrast to earlier studies, the
system evolves under a so-called soft Glauber dynamic [P.A. Rikvold and M.
Kolesik, J. Phys. A: Math. Gen. 35, L117 (2002)], for which both nucleation and
interface propagation are slower and the interfaces smoother than for the
standard Glauber dynamic. We choose the temperature and magnitude of the
external field such that the metastable decay of the system following field
reversal occurs through nucleation and growth of many droplets of the stable
phase, i.e., the multidroplet regime. Using kinetic Monte Carlo simulations, we
find that the system undergoes a nonequilibrium phase transition, in which the
symmetry-broken dynamic phase corresponds to an asymmetric stationary limit
cycle for the time-dependent magnetization. The critical point is located where
the half-period of the external field is approximately equal to the metastable
lifetime of the system. We employ finite-size scaling analysis to investigate
the characteristics of this dynamical phase transition. The critical exponents
and the fixed-point value of the fourth-order cumulant are found to be
consistent with the universality class of the two-dimensional equilibrium Ising
model. As this universality class has previously been established for the same
nonequilibrium model evolving under the standard Glauber dynamic, our results
indicate that this far-from-equilibrium phase transition is universal with
respect to the choice of the stochastic dynamics.