title:
Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM
  Systems

abstract:
  Most existing work on adaptive allocation of subcarriers and power in
multiuser orthogonal frequency division multiplexing (OFDM) systems has focused
on homogeneous traffic consisting solely of either delay-constrained data
(guaranteed service) or non-delay-constrained data (best-effort service). In
this paper, we investigate the resource allocation problem in a heterogeneous
multiuser OFDM system with both delay-constrained (DC) and
non-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate
of all the users with NDC traffic while maintaining guaranteed rates for the
users with DC traffic under a total transmit power constraint. Through our
analysis we show that the optimal power allocation over subcarriers follows a
multi-level water-filling principle; moreover, the valid candidates competing
for each subcarrier include only one NDC user but all DC users. By converting
this combinatorial problem with exponential complexity into a convex problem or
showing that it can be solved in the dual domain, efficient iterative
algorithms are proposed to find the optimal solutions. To further reduce the
computational cost, a low-complexity suboptimal algorithm is also developed.
Numerical studies are conducted to evaluate the performance the proposed
algorithms in terms of service outage probability, achievable transmission rate
pairs for DC and NDC traffic, and multiuser diversity.


title: Generalized Entropy and Transport Coefficients of Hadronic Matter

abstract:
  We use the generalized entropy four-current of the Muller-Israel-Stewart
(MIS) theory of relativistic dissipative fluids to obtain information about
fluctuations around equilibrium. This allows one to compute the non-classical
coefficients of the entropy 4-flux in terms of the equilibrium distribution
functions. The Green-Kubo formulae are used to compute the classical or
standard transport coefficients from the fluctuations of entropy due to
dissipative fluxes.


title:
Probing deviation of tribimaximal mixing and reach of $\theta_{13}$
  using neutrino factory at CERN and ICAL detector at INO

abstract:
  We investigate the deviation from tribimaximal mixing value and the reach of
$\theta_{13}$ using neutrino factory at CERN and ICAL detector at INO.


title: Condensation of cloud microdroplets in homogeneous isotropic turbulence

abstract:
  The growth by condensation of small water droplets in a three-dimensional
homogeneous isotropic turbulent flow is considered. Within a simple model of
advection and condensation, the dynamics and growth of millions of droplets are
integrated. A droplet-size spectra broadening is obtained and it is shown to
increase with the Reynolds number of turbulence, by means of two series of
direct numerical simulations at increasing resolution. This is a key point
towards a proper evaluation of the effects of turbulence for condensation in
warm clouds, where the Reynolds numbers typically achieve huge values. The
obtained droplet-size spectra broadening as a function of the Reynolds number
is shown to be consistent with dimensional arguments. A generalization of this
expectation to Reynolds numbers not accessible by DNS is proposed, yielding
upper and lower bounds to the actual size-spectra broadening. A further DNS
matching the large scales of the system suggests consistency of the picture
drawn, while additional effort is needed to evaluate the impact of this effect
for condensation in more realistic cloud conditions.


title:
Effects of Non-Identical Rayleigh Fading on Differential Unitary
  Space-Time Modulation

abstract: This paper has been withdrawn by the author.


title:
Rigidity in the intersection of varieties does not imply rigidity in the
  intersecting varieties

abstract:
  This paper has been withdrawn by the author due to a crucial error in
example.


title: Nontraditional Scoring of C-tests

abstract:
  In C-tests the hypothesis of items local independence is violated, which
doesn't permit to consider them as real tests. It is suggested to determine the
distances between separate C-test items (blanks) and to combine items into
clusters. Weights, inversely proportional to the number of items in
corresponding clusters, are assigned to items. As a result, the C-test
structure becomes similar to the structure of classical tests, without
violation of local independence hypothesis.


title: Lateral migration of a 2D vesicle in unbounded Poiseuille flow

abstract:
  The migration of a suspended vesicle in an unbounded Poiseuille flow is
investigated numerically in the low Reynolds number limit. We consider the
situation without viscosity contrast between the interior of the vesicle and
the exterior. Using the boundary integral method we solve the corresponding
hydrodynamic flow equations and track explicitly the vesicle dynamics in two
dimensions. We find that the interplay between the nonlinear character of the
Poiseuille flow and the vesicle deformation causes a cross-streamline migration
of vesicles towards the center of the Poiseuille flow. This is in a marked
contrast with a result [L.G. Leal, Ann. Rev. Fluid Mech. 12,
435(1980)]according to which the droplet moves away from the center (provided
there is no viscosity contrast between the internal and the external fluids).
The migration velocity is found to increase with the local capillary number
(defined by the time scale of the vesicle relaxation towards its equilibrium
shape times the local shear rate), but reaches a plateau above a certain value
of the capillary number. This plateau value increases with the curvature of the
parabolic flow profile. We present scaling laws for the migration velocity.


title: On the performance of FDR control: Constraints and a partial solution

abstract:
  The False Discovery Rate (FDR) paradigm aims to attain certain control on
Type I errors with relatively high power for multiple hypothesis testing. The
Benjamini--Hochberg (BH) procedure is a well-known FDR controlling procedure.
Under a random effects model, we show that, in general, unlike the FDR, the
positive FDR (pFDR) of the BH procedure cannot be controlled at an arbitrarily
low level due to the limited evidence provided by the observations to separate
false and true nulls. This results in a criticality phenomenon, which is
characterized by a transition of the procedure's power from being positive to
asymptotically 0 without any reduction in the pFDR, once the target FDR control
level is below a positive critical value. To address the constraints on the
power and pFDR control imposed by the criticality phenomenon, we propose a
procedure which applies BH-type procedures at multiple locations in the domain
of $p$-values. Both analysis and simulations show that the proposed procedure
can attain substantially improved power and pFDR control.


title: Measurement of sigma_Total in e+e- Annihilations Below 10.56 GeV

abstract:
  Using the CLEO III detector, we measure absolute cross sections for e+e- ->
hadrons at seven center-of-mass energies between 6.964 and 10.538 GeV. R, the
ratio of hadronic and muon pair production cross sections, is measured at these
energies with a r.m.s. error <2% allowing determinations of the strong coupling
alpha_s. Using the expected evolution of alpha_s with energy we find
alpha_s(M_Z^2)=0.126 +/- 0.005 ^{+0.015}_{-0.011}, and
Lambda=0.31^{+0.09+0.29}_{-0.08-0.21}.


title: Transient magnetotransport through a quantum wire

abstract:
  We consider an ideal parabolic quantum wire in a perpendicular magnetic
field. A simple Gaussian shaped scattering potential well or hill is flashed
softly on and off with its maximum at $t=0$, mimicking a temporary broadening
or narrowing of the wire. By an extension of the Lippmann-Schwinger formalism
to time-dependent scattering potentials we investigate the effects on the
continuous current that is driven through the quantum wire with a vanishingly
small forward bias. The Lippmann-Schwinger approach to the scattering process
enables us to investigate the interplay between geometrical effects and effects
caused by the magnetic field.


title: Smooth rationally connected threefolds contain all smooth curves

abstract:
  We show that if X is a smooth rationally connected threefold and C is a
smooth projective curve then C can be embedded in X. Furthermore, a version of
this property characterises rationally connected varieties of dimension at
least 3. We give some details about the toric case.


title: Bounded modes to the rescue of optical transmission

abstract:
  This paper presents a brief survey of the evolution of knowledge about
diffraction gratings. After recalling some basic facts, historically and
physically, we introduce the concept of Wood anomalies. Next, we present some
recent works in order to introduce the role of bounded modes in transmission
gratings. The consequences of these recent results are then introduced. This
paper is a secondary publication, published in Europhysics News (EPN 38, 3
(2007) 27-31). In the present version, some additional notes have been added
with related references.


title: Continuous Abelian Sandpile Model in Two Dimensional Lattice

abstract:
  We define a new version of sandpile model which is very similar to Abelian
Sandpile Model (ASM), but the height variables are continuous ones. With the
toppling rule we define in our model, we show that the model can be mapped to
ASM, so the general properties of the two models are identical. Yet the new
model allows us to investigate some problems such as effect of very small mass
on the height probabilities, different boundary conditions, etc.


title:
Electronic transitions in Rydberg Matter as the source of the
  unidentified infrared bands (UIR) observed in interstellar space

abstract:
  Rydberg Matter (RM) theory is previously shown to give good agreement with
the unidentified infrared bands (UIR, UIB) that are observed in emission from
many objects in space. From stimulated emission studies in RM, a slightly
simpler theoretical model is found that describes the transitions giving the
UIR bands better. The general theory for RM was recently shown to be very
accurate using rotational spectroscopy to observe several types of RM clusters
(Mol. Phys. 105 (2007) 933). Two different large studies of UIR are now
interpreted with the improved model. High-resolution UIR observations by
Beintema et al. are interpreted as transitions from high levels n = 40 - 80
down to levels n = 5 - 12 in the final state. The upper level quantum numbers
for the observed bands agree well with those found in experiments. The
stationary UIR bands at 3.3 and 11.3 micrometer are due to deexcitation n = 9
-> 5 and 9 -> 7 of Rydberg species through stimulated emission. The other UIR
bands vary considerably in wavelength in different environments and even with
time as seen in numerous observational studies. Their great variability is
difficult to model by the commonly used PAH model, but is a natural consequence
of the varying excitation state of RM.


title: Theories for the Fermi Scale

abstract:
  I give a short review of our present understanding of new theories of the
electroweak scale, with emphasis on recent progress. Plenary talk at the EPS
2007 Conference at Manchester.


title: Phase control algorithms for focusing light through turbid media

abstract:
  Light propagation in materials with microscopic inhomogeneities is affected
by scattering. In scattering materials, such as powders, disordered
metamaterials or biological tissue, multiple scattering on sub-wavelength
particles makes light diffuse. Recently, we showed that it is possible to
construct a wavefront that focuses through a solid, strongly scattering object.
The focusing wavefront uniquely matches a certain configuration of the
particles in the medium. To focus light through a turbid liquid or living
tissue, it is necessary to dynamically adjust the wavefront as the particles in
the medium move. Here we present three algorithms for constructing a wavefront
that focuses through a scattering medium. We analyze the dynamic behavior of
these algorithms and compare their sensitivity to measurement noise. The
algorithms are compared both experimentally and using numerical simulations.
The results are in good agreement with an intuitive model, which may be used to
develop dynamic diffusion compensators with applications in, for example, light
delivery in human tissue.


title:
One more approach to the convergence of the empirical process to the
  Brownian bridge

abstract:
  A theorem of Donsker asserts that the empirical process converges in
distribution to the Brownian bridge. The aim of this paper is to provide a new
and simple proof of this fact.


title:
Computing the optimal protocol for finite-time processes in stochastic
  thermodynamics

abstract:
  Asking for the optimal protocol of an external control parameter that
minimizes the mean work required to drive a nano-scale system from one
equilibrium state to another in finite time, Schmiedl and Seifert ({\it Phys.
Rev. Lett.} {\bf 98}, 108301 (2007)) found the Euler-Lagrange equation to be a
non-local integro-differential equation of correlation functions. For two
linear examples, we show how this integro-differential equation can be solved
analytically. For non-linear physical systems we show how the optimal protocol
can be found numerically and demonstrate that there may exist several distinct
optimal protocols simultaneously, and we present optimal protocols that have
one, two, and three jumps, respectively.


title:
Stability of monolayers and bilayers in a copolymer-homopolymer blend
  model

abstract:
  We study the stability of layered structures in a variational model for
diblock copolymer-homopolymer blends. The main step consists of calculating the
first and second derivative of a sharp-interface Ohta-Kawasaki energy for
straight mono- and bilayers. By developing the interface perturbations in a
Fourier series we fully characterise the stability of the structures in terms
of the energy parameters.
  In the course of our computations we also give the Green's function for the
Laplacian on a periodic strip and explain the heuristic method by which we
found it.


title: Many body physics and the capacity of quantum channels with memory

abstract:
  In most studies of the capacity of quantum channels, it is assumed that the
errors in each use of the channel are independent. However, recent work has
begun to investigate the effects of memory or correlations in the error, and
has led to suggestions that there can be interesting non-analytic behaviour in
the capacity of such channels. In a previous paper we pursued this issue by
connecting the study of channel capacities under correlated error to the study
of critical behaviour in many-body physics. This connection enables the use of
techniques from many-body physics to either completely solve or understand
qualitatively a number of interesting models of correlated error with analogous
behaviour to associated many-body systems. However, in order for this approach
to work rigorously, there are a number of technical properties that need to be
established for the lattice systems being considered. In this article we
discuss these properties in detail, and establish them for some classes of
many-body system.


title:
Self-organization of irregular NEM vibrations in multi-mode shuttle
  structures

abstract:
  We investigate theoretically multi-mode electromechanical "shuttle"
instabilities in DC voltage-biased nanoelectromechanical single-electron
tunneling (NEM-SET) devices. We show that initially irregular (quasi-periodic)
oscillations, that occur as a result of the simultaneous self-excitation of
several mechanical modes with incommensurable frequencies, self-organize into
periodic oscillations with a frequency corresponding to the eigenfrequency of
one of the unstable modes. This effect demonstrates that a local probe can
selectively excite global vibrations of extended objects.


title: Deleting a marked item from an unsorted database with a single query

abstract:
  In this Letter we present a quantum deletion algorithm that deletes a marked
state from an unsorted database of $N$ items with only a single query. This
algorithm achieves exponential speedup compared with classical algorithm where
O(N) number of query is required. General property of this deleting algorithm
is also studied.


title: On the Caudrey-Beals-Coifman System and the Gauge Group Action

abstract:
  The generalized Zakharov-Shabat systems with complex-valued Cartan elements
and the systems studied by Caudrey, Beals and Coifman (CBC systems) and their
gauge equivalent are studies. This includes: the properties of fundamental
analytical solutions (FAS) for the gauge-equivalent to CBC systems and the
minimal set of scattering data; the description of the class of nonlinear
evolutionary equations solvable by the inverse scattering method and the
recursion operator, related to such systems; the hierarchies of Hamiltonian
structures.


title: On a conjecture of Serre on abelian threefolds

abstract:
  In this article, we give a reformulation of a result from Howe, Leprevost and
Poonen on a three dimensional family of abelian threefolds. We also link their
result to a conjecture of Serre on a precise form of Torelli theorem for genus
3 curves.


title: Measured quantum probability distribution functions for Brownian motion

abstract:
  The quantum analog of the joint probability distributions describing a
classical stochastic process is introduced. A prescription is given for
constructing the quantum distribution associated with a sequence of
measurements. For the case of quantum Brownian motion this prescription is
illustrated with a number of explicit examples. In particular it is shown how
the prescription can be extended in the form of a general formula for the
Wigner function of a Brownian particle entangled with a heat bath.


title:
Automatic Methods for Analyzing Non-Repudiation Protocols with an Active
  Intruder

abstract:
  Non-repudiation protocols have an important role in many areas where secured
transactions with proofs of participation are necessary. Formal methods are
clever and without error, therefore using them for verifying such protocols is
crucial. In this purpose, we show how to partially represent non-repudiation as
a combination of authentications on the Fair Zhou-Gollmann protocol. After
discussing its limits, we define a new method based on the handling of the
knowledge of protocol participants. This method is very general and is of
natural use, as it consists in adding simple annotations, like for
authentication problems. The method is very easy to implement in tools able to
handle participants knowledge. We have implemented it in the AVISPA Tool and
analyzed the optimistic Cederquist-Corin- Dashti protocol, discovering two
unknown attacks. This extension of the AVISPA Tool for handling non-repudiation
opens a highway to the specification of many other properties, without any more
change in the tool itself.


title: Light-mass Bragg cavity polaritons in planar quantum dot lattices

abstract:
  The exciton-polariton modes of a quantum dot lattice embedded in a planar
optical cavity are theoretically investigated. Umklapp terms, in which an
exciton interacts with many cavity modes differing by reciprocal lattice
vectors, appear in the Hamiltonian due to the periodicity of the dot lattice.
We focus on Bragg polariton modes obtained by tuning the exciton and the cavity
modes into resonance at high symmetry points of the Brillouin Zone. Depending
on the microcavity design these polaritons modes at finite in-plane momentum
can be guided and can have long lifetimes. Moreover, their effective mass can
be extremely small, of the order of $10^{-8} m_0$ ($m_0$ is the bare electron
mass), and they constitute the lightest exciton-like quasi-particles in solids.


title: The theory of the "0.7 anomaly" in quantum point contacts

abstract:
  The phenomenology of the "0.7 anomaly" in quantum point contacts is fully
explained in terms of a quasi-localized state, which forms as the point contact
opens up. Detailed numerical calculations within spin-density functional theory
indeed con rm the emergence of such a state. Quantitative calculations of the
conductance and the noise are obtained using a model based on these
observations, and are in excellent agreement with existing experimental
observations.


title:
Multicomponent solution in modified theory of gravity in the early
  universe

abstract:
  We study the modified theory of gravity in Friedmann Robertson Walker
universe composed of several perfect fluids. We consider the power law
inflation and determine the equation of state parameters in terms of the
parameters of modified gravity's Lagrangian in the early universe. We also
discuss briefly the gravitational baryogenesis in this model.


title:
Radiative corrections to W-boson hadroproduction: higher-order
  electroweak and supersymmetric effects

abstract:
  The high accuracy envisaged for future measurements of W-boson production at
hadron colliders has to be matched by precise theoretical predictions. We study
the impact of electroweak radiative corrections on W-boson production cross
sections and differential distributions at the Tevatron and at the LHC. In
particular, we include photon-induced processes, which contribute at O(alpha),
and leading radiative corrections beyond O(alpha) in the high-energy Sudakov
regime and from multi-photon final-state radiation. We furthermore present the
calculation of the complete supersymmetric next-to-leading-order electroweak
and QCD corrections to W-boson hadroproduction within the MSSM. The
supersymmetric corrections turn out to be negligible in the vicinity of the W
resonance in general, reaching the percent level only at high lepton transverse
momentum and for specific choices of the supersymmetric parameters.


title:
Two-parameter model predictions and theta-point crossover for
  linear-polymer solutions

abstract:
  We consider the first few virial coefficients of the osmotic pressure, the
radius of gyration, the hydrodynamic radius, and the end-to-end distance for a
monodisperse polymer solution. We determine the corresponding two-parameter
model functions which parametrize the crossover between the good-solvent and
the ideal-chain behavior. These results allow us to predict the osmotic
pressure and the polymer size in the dilute regime in a large temperature
region above the theta-point.


title:
Global firing induced by network disorder in ensembles of active
  rotators

abstract:
  We study the influence of repulsive interactions on an ensemble of coupled
excitable rotators. We find that a moderate fraction of repulsive interactions
can trigger global firing of the ensemble. The regime of global firing,
however, is suppressed in sufficiently large systems if the network of
repulsive interactions is fully random, due to self-averaging in its degree
distribution. We thus introduce a model of partially random networks with a
broad degree distribution, where self-averaging due to size growth is absent.
In this case, the regime of global firing persists for large sizes. Our results
extend previous work on the constructive effects of diversity in the collective
dynamics of complex systems.


title: On C-fibrations over projective curves

abstract:
  The goal of this paper is to present a modified version (GML) of ML invariant
which should take into account rulings over a projective base and allow further
stratification of smooth affine rational surfaces. We provide a non-trivial
example where GML invariant is computed for a smooth affine rational surface
admitting no C-actions. We apply GML invariant to computation of ML invariant
of some threefolds.


title: On the gamma-ray emission of Type Ia Supernovae

abstract:
  A multi-dimension, time-dependent Monte Carlo code is used to compute sample
gamma-ray spectra to explore whether unambiguous constraints could be obtained
from gamma-ray observations of Type Ia supernovae. Both spherical and
aspherical geometries are considered and it is shown that moderate departures
from sphericity can produce viewing-angle effects that are at least as
significant as those caused by the variation of key parameters in
one-dimensional models. Thus gamma-ray data could in principle carry some
geometrical information, and caution should be applied when discussing the
value of gamma-ray data based only on one-dimensional explosion models. In
light of the limited sensitivity of current gamma-ray observatories, the
computed theoretical spectra are studied to revisit the issue of whether useful
constraints could be obtained for moderately nearby objects. The most useful
gamma-ray measurements are likely to be of the light curve and time-dependent
hardness ratios, but sensitivity higher than currently available, particularly
at relatively hard energies (~2-3 MeV), is desirable.


title:
Pulsational pair instability as an explanation for the most luminous
  supernovae

abstract:
  The extremely luminous supernova SN 2006gy challenges the traditional view
that the collapse of a stellar core is the only mechanism by which a massive
star makes a supernova, because it seems too luminous by more than a factor of
ten. Here we report that the brightest supernovae in the modern Universe arise
from collisions between shells of matter ejected by massive stars that undergo
an interior instability arising from the production of electron-positron pairs.
This "pair instability" leads to explosive burning that is insufficient to
unbind the star, but ejects many solar masses of the envelope. After the first
explosion, the remaining core contracts and searches for a stable burning
state. When the next explosion occurs, several solar masses of material are
again ejected, which collide with the earlier ejecta. This collision can
radiate 1E50 erg of light, about a factor of ten more than an ordinary
supernova. Our model is in good agreement with the observed light curve for SN
2006gy and also shows that some massive stars can produce more than one
supernova-like outburst.


title:
Can the Quantum Measurement Problem be resolved within the framework of
  Schroedinger Dynamics and Quantum Probability?

abstract:
  We provide an affirmative answer to the question posed in the title. Our
argument is based on a treatment of the Schroedinger dynamics of the composite
of a quantum microsystem, S, and a macroscopic measuring apparatus, I,
consisting of N interacting particles. The pointer positions of this apparatus
are represented by orthogonal subspaces of its representative Hilbert space
that are simultaneous eigenspaces of coarse-grained macroscopic observables. By
taking explicit account of their macroscopicality via a large deviation
principle, we prove that, for a suitably designed apparatus I, the evolution of
the composite (S+I) leads both to the reduction of the wave packet of S and to
a one-to-one correspondence between the resultant state of this microsystem and
the pointer position of I, up to utterly negligible corrections that decrease
exponentially with N.


title:
Internal-state thermometry by depletion spectroscopy in a cold guided
  beam of formaldehyde

abstract:
  We present measurements of the internal state distribution of
electrostatically guided formaldehyde. Upon excitation with continuous tunable
ultraviolet laser light the molecules dissociate, leading to a decrease in the
molecular flux. The population of individual guided states is measured by
addressing transitions originating from them. The measured populations of
selected states show good agreement with theoretical calculations for different
temperatures of the molecule source. The purity of the guided beam as deduced
from the entropy of the guided sample using a source temperature of 150K
corresponds to that of a thermal ensemble with a temperature of about 30 K.


title:
Surface effects in magnetic superconductors with a spiral magnetic
  structure

abstract:
  We consider a magnetic superconductor MS with a spiral magnetic structure. On
the basis of generalized Eilenberger and Usadel equations we show that near the
boundary of the MS with an insulator or vacuum the condensate (Gor'kov's)
Green's functions are disturbed by boundary conditions and differ essentially
from their values in the bulk. Corrections to the bulk quasiclassical Green's
functions oscillate with the period of the magnetic spiral, $2\pi /Q$, and
decay inside the superconductor over a length of the order $v/\pi T$ (ballistic
limit) or $\sqrt{D/\pi T}$ (diffusive limit). We calculate the dc Josephson
current in an MS/I/MS tunnel junction and show that the critical Josephson
current differs substantially from that obtained with the help of the tunnel
Hamiltonian method and bulk Green's functions.


title: CP violation in chargino production in e+e- collisions

abstract:
  We present the analysis of CP-violating effects in non-diagonal chargino pair
production in e+e- collisions. These effects appear only at the one-loop level.
We show that CP-odd asymmetries in chargino production are sensitive to the
phases of mu and A_t parameters and can be of the order of a few %.


title: Correlations in connected random graphs

abstract:
  We study the properties of the giant connected component in random graphs
with arbitrary degree distribution. We concentrate on the degree-degree
correlations. We show that the adjoining nodes in the giant connected component
are correlated and derive analytic formulas for the joint nearest-neighbor
degree probability distribution. Using those results we describe the
correlations in maximal entropy connected random graphs. We show that connected
graphs are disassortative and that correlations are strongly related to the
presence of one-degree nodes (leaves). We propose an efficient algorithm for
generating connected random graphs. We illustrate our results with several
examples.


title: Complex Networks: Time-Dependent Connections and Silent Nodes

abstract:
  We studied, both analytically and numerically, complex excitable networks, in
which connections are time dependent and some of the nodes remain silent at
each time step. More specifically, (a) there is a heterogenous distribution of
connection weights and, depending on the current degree of order, some
connections are reinforced/weakened with strength Phi on short-time scales, and
(b) only a fraction rho of nodes are simultaneously active. The resulting
dynamics has attractors which, for a range of Phi values and rho exceeding a
threshold, become unstable, the instability depending critically on the value
of rho. We observe that (i) the activity describes a trajectory in which the
close neighborhood of some of the attractors is constantly visited, (ii) the
number of attractors visited increases with rho, and (iii) the trajectory may
change from regular to chaotic and vice versa as rho is, even slightly
modified. Furthermore, (iv) time series show a power-law spectra under
conditions in which the attractors' space is most efficiently explored. We
argue on the possible qualitative relevance of this phenomenology to networks
in several natural contexts.


title:
Efficient formalism for large scale ab initio molecular dynamics based
  on time-dependent density functional theory

abstract:
  A new "on the fly" method to perform Born-Oppenheimer ab initio molecular
dynamics (AIMD) is presented. Inspired by Ehrenfest dynamics in time-dependent
density functional theory, the electronic orbitals are evolved by a
Schroedinger-like equation, where the orbital time derivative is multiplied by
a parameter. This parameter controls the time scale of the fictitious
electronic motion and speeds up the calculations with respect to standard
Ehrenfest dynamics. In contrast to other methods, wave function orthogonality
needs not be imposed as it is automatically preserved, which is of paramount
relevance for large scale AIMD simulations.


title: On the relation between Bell inequalities and nonlocal games

abstract:
  We investigate the relation between Bell inequalities and nonlocal games by
presenting a systematic method for their bilateral conversion. In particular,
we show that while to any nonlocal game there naturally corresponds a unique
Bell inequality, the converse is not true. As an illustration of the method we
present a number of nonlocal games that admit better odds when played using
quantum resources


title: $D$ and $\bar{D}$ mesons in hot and dense matter

abstract:
  The $D$ and $\bar {D}$ mesons are studied in hot dense matter within a
self-consistent coupled-channel approach taking, as bare interaction, a broken
SU(4) s-wave Tomozawa-Weinberg interaction supplemented by an attractive
isoscalar-scalar term. The in-medium solution at finite temperature
incorporates Pauli blocking effects, baryon mean-field bindings, and $\pi$ and
open-charm meson self-energies. In the $DN$ sector, the $\Lambda_c$ and
$\Sigma_c$ resonances remain close to their free-space position while acquiring
a remarkable width. As a result, the $D$ meson spectral density shows a single
pronounced peak close to the free mass that broadens with increasing density
specially towards lower energies. The low-density theorem is not a good
approximation for the repulsive $\bar D$ self-energy close to saturation
density. We discuss the implications for the $J/\Psi$ suppression at CBM
(FAIR).


title: Topology and Phases in Fermionic Systems

abstract:
  There can exist topological obstructions to continuously deforming a gapped
Hamiltonian for free fermions into a trivial form without closing the gap.
These topological obstructions are closely related to obstructions to the
existence of exponentially localized Wannier functions. We show that by taking
two copies of a gapped, free fermionic system with complex conjugate
Hamiltonians, it is always possible to overcome these obstructions. This allows
us to write the ground state in matrix product form using Grassman-valued bond
variables, and show insensitivity of the ground state density matrix to
boundary conditions.


title: Testing CPT Symmetry with CMB Measurements

abstract:
  In this paper we study the possibility of testing \emph{CPT} symmetry with
Cosmic Microwave Background (CMB) measurements. Working with an effective
lagrangian of the photon with \emph{CPT} violation ${\cal L} \sim
p_{\mu}A_{\nu}\tilde F^{\mu\nu}$ which causes the polarization vectors of the
propagating CMB photons rotated, we determine the rotation angle $\Delta\alpha$
using the BOOMERanG 2003 and the WMAP3 angular power spectra. In this analysis
we have included the newly released $TC$ and $GC$ ($l<450$) information of
WMAP3 and found $\Delta\alpha=-6.2\pm3.8$ deg at $1\sigma$ confidence level.
This result increases slightly the significance for the \emph{CPT} violation
obtained in our previous paper (Feng \emph{et al.}, 2006) $\Delta\alpha=-6.0
\pm 4.0$ deg (1$\sigma$). Furthermore we examine the constraint on the rotation
angle with the simulated Planck data. Our results show that the Planck will be
sensitive to $\Delta \alpha$ at the level of 0.057 deg and able to test the
\emph{CPT} symmetry with a higher precision.


title: Narrow-Line Seyfert 1 Galaxies

abstract:
  I provide a short review of the properties of Narrow-line Seyfert 1 (NLS1)
galaxies across the electromagnetic spectrum and of the models to explain them.
Their continuum and emission-line properties manifest one extreme form of
Seyfert activity. As such, NLS1 galaxies may hold important clues to the key
parameters that drive nuclear activity. Their high accretion rates close to the
Eddington rate provide new insight into accretion physics, their low black hole
masses and perhaps young ages allow us to address issues of black hole growth,
their strong optical FeII emission places strong constraints on FeII and
perhaps metal formation models and physical conditions in these emission-line
clouds, and their enhanced radio quiteness permits a fresh look at causes of
radio loudness and the radio-loud radio-quiet bimodality in AGN.


title: A la Fock-Goncharov coordinates for PU(2,1)

abstract:
  We describe a set of coordinates on the PU(2,1)-representation variety of the
fundamental group of an oriented punctured surface $S$ with negative Euler
characteristic. The main technical tool we use is a set of geometric invariants
of a triple of flags in the complex hyperpolic plane. We establish a bijection
between a set of decorations of an ideal triangulation of $S$ and a subset of
the PU(2,1)-representation variety of $\pi_1(S)$.


title:
Discussion of the Electromotive Force Terms in the Model of
  Parker-unstable Galactic Disks with Cosmic Rays and Shear

abstract:
  We analyze the electromotive force (EMF) terms and basic assumptions of the
linear and nonlinear dynamo theories in our three-dimensional (3D) numerical
model of the Parker instability with cosmic rays and shear in a galactic disk.
We also apply the well known prescriptions of the EMF obtained by the nonlinear
dynamo theory (Blackman & Field 2002 and Kleeorin et al. 2003) to check if the
EMF reconstructed from their prescriptions corresponds to the EMF obtained
directly from our numerical models. We show that our modeled EMF is fully
nonlinear and it is not possible to apply any of the considered nonlinear
dynamo approximations due to the fact that the conditions for the scale
separation are not fulfilled.


title: Universality and programmability of quantum computers

abstract:
  Manin, Feynman, and Deutsch have viewed quantum computing as a kind of
universal physical simulation procedure. Much of the writing about quantum
logic circuits and quantum Turing machines has shown how these machines can
simulate an arbitrary unitary transformation on a finite number of qubits. The
problem of universality has been addressed most famously in a paper by Deutsch,
and later by Bernstein and Vazirani as well as Kitaev and Solovay. The quantum
logic circuit model, developed by Feynman and Deutsch, has been more prominent
in the research literature than Deutsch's quantum Turing machines. Quantum
Turing machines form a class closely related to deterministic and probabilistic
Turing machines and one might hope to find a universal machine in this class. A
universal machine is the basis of a notion of programmability. The extent to
which universality has in fact been established by the pioneers in the field is
examined and this key notion in theoretical computer science is scrutinised in
quantum computing by distinguishing various connotations and concomitant
results and problems.


title:
Astrophysics from data analysis of spherical gravitational wave
  detectors

abstract:
  The direct detection of gravitational waves will provide valuable
astrophysical information about many celestial objects. Also, it will be an
important test to general relativity and other theories of gravitation. The
gravitational wave detector SCHENBERG has recently undergone its first test
run. It is expected to have its first scientific run soon. In this work the
data analysis system of this spherical, resonant mass detector is tested
through the simulation of the detection of gravitational waves generated during
the inspiralling phase of a binary system. It is shown from the simulated data
that it is not necessary to have all six transducers operational in order to
determine the source's direction and the wave's amplitudes.


title:
On a possible origin of a resonance-like structure in the two-photon
  invariant mass spectrum of the reaction pp->ppgg

abstract:
  We show that the resonance-like structure found by the \emph{CELSIUS-WASA
Collaboration} in the two-photon invariant mass spectrum of the reaction $pp
\to pp \gamma \gamma$ is rather a signature of the $NN$-decoupled dibaryon
resonance $d^\star_1$(1956) that is produced in the radiative process $pp \to
\gamma d^\star_1$ and then undergoes radiative decay into two protons
$d^\star_1 \to pp \gamma$. It is found that a contribution of the dibaryon
mechanism $pp \to \gamma d^\star_1 \to pp \gamma \gamma$ of the reaction $pp
\to pp \gamma \gamma$ to the invariant mass spectrum of its photon pairs can
reasonably well reproduce the experimentally observed spectrum in the vicinity
of the resonance-like structure.


title: Model and Program Repair via SAT Solving

abstract:
  We consider the following \emph{model repair problem}: given a finite Kripke
structure $M$ and a specification formula $\eta$ in some modal or temporal
logic, determine if $M$ contains a substructure $M'$ (with the same initial
state) that satisfies $\eta$. Thus, $M$ can be ``repaired'' to satisfy the
specification $\eta$ by deleting some transitions.
  We map an instance $(M, \eta)$ of model repair to a boolean formula
$\repfor(M,\eta)$ such that $(M, \eta)$ has a solution iff $\repfor(M,\eta)$ is
satisfiable. Furthermore, a satisfying assignment determines which transitions
must be removed from $M$ to generate a model $M'$ of $\eta$. Thus, we can use
any SAT solver to repair Kripke structures. Furthermore, using a complete SAT
solver yields a complete algorithm: it always finds a repair if one exists.
  We extend our method to repair finite-state shared memory concurrent
programs, to solve the discrete event supervisory control problem
\cite{RW87,RW89}, to check for the existence of symmettric solutions
\cite{ES93}, and to accomodate any boolean constraint on the existence of
states and transitions in the repaired model.
  Finally, we show that model repair is NP-complete for CTL, and logics with
polynomial model checking algorithms to which CTL can be reduced in polynomial
time. A notable example of such a logic is Alternating-Time Temporal Logic
(ATL).


title: Non-linear mechanical response of the Red Blood Cell

abstract:
  We measure the dynamical mechanical properties of human red blood cells.
Single cell response is measured with optical tweezers. We investigate both the
stress relaxation following a fast deformation, and the effect of varying the
strain rate. We find a power law decay of the stress as a function of time,
down to a plateau stress, and a power law increase of the cell's elasticity as
a function of the strain rate. Interestingly, the exponents of these quantities
violate the linear superposition principle, indicating a nonlinear response. We
propose that this is due to breaking of a fraction of the crosslinks during the
deformation process. The Soft Glassy Rheology Model accounts for the relation
between the exponents we observe experimentally. This picture is consistent
with recent models of bond remodeling in the red blood cell's molecular
structure. Our results imply that the blood cell's mechanical behavior depends
critically on the deformation process.


title: Speculations on Isolated Lepton Events at HERA

abstract:
  Speculations on mechanisms which might be responsible for events with an
isolated high p_T lepton, a hadron jet and missing energy, as observed in the
H1 experiment at HERA, are discussed.


title:
Non-linear numerical simulations of magneto-acoustic wave propagation in
  small-scale flux tubes

abstract:
  We present results of non-linear, 2D, numerical simulations of
magneto-acoustic wave propagation in the photosphere and chromosphere of
small-scale flux tubes with internal structure. Waves with realistic periods of
three to five minutes are studied, after applying horizontal and vertical
oscillatory perturbations to the equilibrium model. Spurious reflections of
shock waves from the upper boundary are minimized thanks to a special boundary
condition. This has allowed us to increase the duration of the simulations and
to make it long enough to perform a statistical analysis of oscillations. The
simulations show that deep horizontal motions of the flux tube generate a slow
(magnetic) mode and a surface mode. These modes are efficiently transformed
into a slow (acoustic) mode in the vA < cS atmosphere. The slow (acoustic) mode
propagates vertically along the field lines, forms shocks and remains always
within the flux tube. It might deposit effectively the energy of the driver
into the chromosphere. When the driver oscillates with a high frequency, above
the cut-off, non-linear wave propagation occurs with the same dominant driver
period at all heights. At low frequencies, below the cut-off, the dominant
period of oscillations changes with height from that of the driver in the
photosphere to its first harmonic (half period) in the chromosphere. Depending
on the period and on the type of the driver, different shock patterns are
observed.


title: Potts Glass on Random Graphs

abstract:
  We solve the q-state Potts model with anti-ferromagnetic interactions on
large random lattices of finite coordination. Due to the frustration induced by
the large loops and to the local tree-like structure of the lattice this model
behaves as a mean field spin glass. We use the cavity method to compute the
temperature-coordination phase diagram and to determine the location of the
dynamic and static glass transitions, and of the Gardner instability. We show
that for q>=4 the model possesses a phenomenology similar to the one observed
in structural glasses. We also illustrate the links between the positive and
the zero-temperature cavity approaches, and discuss the consequences for the
coloring of random graphs. In particular we argue that in the colorable region
the one-step replica symmetry breaking solution is stable towards more steps of
replica symmetry breaking.


title: Structure and properties of the vacuum of the Twisted Eguchi-Kawai model

abstract:
  We investigate numerically the phase structure of the Twisted Eguchi-Kawai
(TEK) model in four dimensions. In the numerical simulations of the zero
temperature TEK model (using a symmetric twist) we observe the existence of new
phases that break its centre symmetry at intermediate lattice couplings and for
large SU(N) gauge groups. This effect can be explained by the contribution of
diagonal configurations with collapsed eigenvalues, which are particular cases
of ``generalised fluxons''. We also investigate finite temperature versions of
the TEK model using anisotropic lattice couplings, where in particular we find
van Baal fluxons contributing at large anisotropies.


title:
Search for Randall-Sundrum gravitons with 1 fb-1 of data from ppbar
  collisions at sqrt(s)=1.96 TeV

abstract:
  Using 1 fb-1 of data from ppbar collisions at sqrt(s)=1.96 TeV at the
Fermilab Tevatron collider collected by the D0 detector, we search for decays
of Kaluza-Klein excitations of the graviton in the Randall-Sundrum model of
extra dimensions to e+e- and diphotons. We set 95% confidence level upper
limits on the production cross section times branching fraction which translate
into lower limits on the mass of the lightest excitation between 300 and 900
GeV for values of the coupling k/M(Planck) between 0.01 and 0.1.


title:
Investigation of the bottomonium ground state \eta_b via its inclusive
  charm decays

abstract:
  Based on the non-relativistic QCD factorization formalism, we calculate the
bottomonium ground state, $\eta_b$, inclusive charm decays at the leading order
in the strong coupling constant $\alpha_s$ and quarkonium internal relative
velocity $v$. The inclusive charm pair production in $\eta_b$ decay is mainly
realized through $\eta_b \to c \bar{c} g$ process, where the charm and
anti-charm quarks then dominantly hadronize into charmed hadrons. The momentum
distributions of the final states are presented. In this work, we also
calculate the $J/\psi$ inclusive production rate in the $\eta_b$ decays, where
the color-octet contribution is found to be very important. We expect this
study may shed some light on finding $\eta_b$ or knowing more about its nature.


title: Distances to Galactic high-velocity clouds. Complex C

abstract:
  We report the first determination of a distance bracket for the high-velocity
cloud (HVC) complex C. Combined with previous measurements showing that this
cloud has a metallicity of 0.15 times solar, these results provide ample
evidence that complex C traces the continuing accretion of intergalactic gas
falling onto the Milky Way. Accounting for both neutral and ionized hydrogen as
well as He, the distance bracket implies a mass of 3-14x10^6 M_sun, and the
complex represents a mass inflow of 0.1-0.25 M_sun/yr. We base our distance
bracket on the detection of CaII absorption in the spectrum of the blue
horizontal branch star SDSS J120404.78+623345.6, in combination with a
significant non-detection toward the BHB star BS 16034-0114. These results set
a strong distance bracket of 3.7-11.2 kpc on the distance to complex C. A more
weakly supported lower limit of 6.7 kpc may be derived from the spectrum of the
BHB star BS 16079-0017.


title:
Discrete, 3D distributed, linear imaging methods of electric neuronal
  activity. Part 1: exact, zero error localization

abstract:
  This paper deals with the EEG/MEG neuroimaging problem: given measurements of
scalp electric potential differences (EEG: electroencephalogram) and
extracranial magnetic fields (MEG: magnetoencephalogram), find the 3D
distribution of the generating electric neuronal activity. This problem has no
unique solution. Only particular solutions with "good" localization properties
are of interest, since neuroimaging is concerned with the localization of brain
function. In this paper, a general family of linear imaging methods with exact,
zero error localization to point-test sources is presented. One particular
member of this family is sLORETA (standardized low resolution brain
electromagnetic tomography; Pascual-Marqui, Methods Find. Exp. Clin. Pharmacol.
2002, 24D:5-12;
http://www.unizh.ch/keyinst/NewLORETA/sLORETA/sLORETA-Math01.pdf). It is shown
here that sLORETA has no localization bias in the presence of measurement and
biological noise. Another member of this family, denoted as eLORETA (exact low
resolution brain electromagnetic tomography; Pascual-Marqui 2005:
http://www.research-projects.unizh.ch/p6990.htm), is a genuine inverse solution
(not merely a linear imaging method) with exact, zero error localization in the
presence of measurement and structured biological noise. The general family of
imaging methods is further extended to include data-dependent (adaptive)
quasi-linear imaging methods, also with the exact, zero error localization
property.


title: The Conjugate Linearized Ricci Flow on Closed 3-Manifolds

abstract:
  We characterize the conjugate linearized Ricci flow and the associated
backward heat kernel on closed three--manifolds of bounded geometry. We discuss
their properties, and introduce the notion of Ricci flow conjugated constraint
sets which characterizes a way of Ricci flow averaging metric dependent
geometrical data. We also provide an integral representation of the Ricci flow
metric itself and of its Ricci tensor in terms of the heat kernel of the
conjugate linearized Ricci flow. These results, which readily extend to closed
n-dimensional manifolds, yield for various conservation laws, monotonicity and
asymptotic formulas for the Ricci flow and its linearization.


title: Entanglement in the F-AF zig-zag Heisenberg chain

abstract:
  We present a study of the entanglement properties of the F-AF zig-zag
Heisenberg chain done by means of the Density Matrix Renormalization Group
method. In particular, we have selected the concurrence as measure of
entanglement and checked its capability to signal the presence of quantum phase
transitions within the previously found ergodicity phase diagram [E. Plekhanov,
A. Avella, and F. Mancini, Phys. Rev. B \textbf{74}, 115120 (2006)]. By
analyzing the behavior of the concurrence, we have been able not only to
determine the position of the transition lines within the phase diagram of the
system, but also to identify a well defined region in the parameter space of
the model that shows a complex spin ordering indicating the presence of a new
phase of the system.


title: Description of Derivations on Measurable Operator Algebras of Type I

abstract:
  Given a type I von Neumann algebra $M$ with a faithful normal semi-finite
trace $\tau,$ let $L(M, \tau)$ be the algebra of all $\tau$-measurable
operators affiliated with $M.$ We give a complete description of all
derivations on the algebra $L(M, \tau).$ In particular, we prove that if $M$ is
of type I$_\infty$ then every derivation on $L(M, \tau)$ is inner.


title: The final spin from the coalescence of aligned-spin black-hole binaries

abstract:
  Determining the final spin of a black-hole (BH) binary is a question of key
importance in astrophysics. Modelling this quantity in general is made
difficult by the fact that it depends on the 7-dimensional space of parameters
characterizing the two initial black holes. However, in special cases, when
symmetries can be exploited, the description can become simpler. For black-hole
binaries with unequal masses but with equal spins which are aligned with the
orbital angular momentum, we show that the use of recent simulations and basic
but exact constraints derived from the extreme mass-ratio limit allow to model
this quantity with a simple analytic expression. Despite the simple dependence,
the expression models very accurately all of the available estimates, with
errors of a couple of percent at most. We also discuss how to use the fit to
predict when a Schwarzschild BH is produced by the merger of two spinning BHs,
when the total angular momentum of the spacetime ``flips'' sign, or under what
conditions the final BH is ``spun-up'' by the merger. Finally, suggest an
extension of the fit to include unequal-spin binaries, thus potentially
providing a complete description of the final spin from the coalescence of
generic black-hole binaries with spins aligned to the orbital angular momentum.


title: Associated charged Higgs and W boson production in the MSSM at the LHC

abstract:
  We investigate the associated production of charged Higgs bosons (H^\pm) and
W bosons at the CERN Large Hadron Collider, using the leptonic decay H^+ ->
tau^+ nu_tau and hadronic W decay, within different scenarios of the Minimal
Supersymmetric Standard Model (MSSM) with both real and complex parameters.
Performing a parton level study we show how the irreducible Standard Model
background from W + 2 jets can be controlled by applying appropriate cuts. In
the standard m_h^max scenario we find a viable signal for large tan beta and
intermediate H^\pm masses (~ m_t). In MSSM scenarios with large mass-splittings
among the heavy Higgs bosons the cross-section can be resonantly enhanced by
factors up to one hundred, with a strong dependence on the CP-violating phases.


title:
The compact group--fossil group connection: observations of a massive
  compact group at z=0.22

abstract:
  It has been suggested that fossil groups could be the cannibalized remains of
compact groups, that lost energy through tidal friction. However, in the nearby
universe, compact groups which are close to the merging phase and display a
wealth of interacting features (such as HCG 31 and HCG 79) have very low
velocity dispersions and poor neighborhoods, unlike the massive, cluster-like
fossil groups studied to date. In fact, known z=0 compact groups are very
seldom embedded in massive enough structures which may have resembled the
intergalactic medium of fossil groups. In this paper we study the dynamical
properties of CG6, a massive compact group at z=0.220 that has several
properties in common with known fossil groups. We report on new g' and i'
imaging and multi-slit spectroscopic performed with GMOS on Gemini South. The
system has 20 members, within a radius of 1 h_70^-1 Mpc, a velocity dispersion
of 700 km/s and has a mass of 1.8 x 10^14 h_70^-1 Msun, similar to that of the
most massive fossil groups known. The merging of the four central galaxies in
this group would form a galaxy with magnitude M_r' ~ -23.4, typical for
first-ranked galaxies of fossil groups. Although nearby compact groups with
similar properties to CG 6 are rare, we speculate that such systems occurred
more frequently in the past and they may have been the precursors of fossil
groups.


title:
Heavy Flavour Production in Deep--Inelastic Scattering - Two--Loop
  Massive Operator Matrix Elements and Beyond

abstract:
  We calculate the O($\eps$)--term of the two--loop massive operator matrix
elements for twist 2--operators, which contribute to the heavy flavour Wilson
coefficients in unpolarized deep--inelastic scattering in the asymptotic limit
$Q^2 \gg m^2.$ Our calculation was performed in Mellin space using
Mellin--Barnes integrals and generalized hypergeometric functions. The
O($\eps$)--term contributes in the renormalization at 3--loop order.


title:
Determining Reheating Temperature at Colliders with Axino or Gravitino
  Dark Matter

abstract:
  After a period of inflationary expansion, the
  Universe reheated and reached full thermal equilibrium at the reheating
temperature T_R. In this work we point out that, in the context of effective
low-energy supersymmetric models, LHC measurements may allow one to determine
T_R as a function of the mass of the dark matter particle assumed to be either
an axino or a gravitino. An upper bound on their mass may also be derived.


title:
Fully Correlated Electronic Dynamics for Antiproton Impact Ionization of
  Helium

abstract:
  We present total cross sections for single and double ionization of helium by
antiproton impact over a wide range of impact energies from 10 keV/amu to 1
MeV/amu. A non-perturbative time-dependent close-coupling method (TDCC) is
applied to fully treat the correlated dynamics of the ionized electrons.
Excellent agreement is obtained between our calculations and experimental
measurements of total single and double ionization cross sections at high
impact energies, whereas for lower impact energies, some discrepancies with
experiment are found. At an impact energy of 1 MeV we also find that the
double-to-single ionization ratio is twice as large for antiproton impact as
for proton impact, confirming a long-standing unexpected experimental
measurement.


title:
The Rich Mid-Infrared Environments of Two Highly-Obscured X-ray
  Binaries: Spitzer Observations of IGR J16318-4848 and GX 301-2

abstract:
  We present the results of Spitzer mid-infrared spectroscopic observations of
two highly-obscured massive X-ray binaries: IGR J16318-4848 and GX301-2. Our
observations reveal for the first time the extremely rich mid-infrared
environments of this type of source, including multiple continuum emission
components (a hot component with T > 700 K and a warm component with T ~ 180 K)
with apparent silicate absorption features, numerous HI recombination lines,
many forbidden ionic lines of low ionization potentials, and pure rotational H2
lines. This indicates that both sources have hot and warm circumstellar dust,
ionized stellar winds, extended low-density ionized regions, and
photo-dissociated regions. It appears difficult to attribute the total optical
extinction of both sources to the hot and warm dust components, which suggests
that there could be an otherwise observable colder dust component responsible
for the most of the optical extinction and silicate absorption features. The
observed mid-infrared spectra are similar to those from Luminous Blue
Variables, indicating that the highly-obscured massive X-ray binaries may
represent a previously unknown evolutionary phase of X-ray binaries with
early-type optical companions. Our results highlight the importance and utility
of mid-infrared spectroscopy to investigate highly-obscured X-ray binaries.


title: Applications of Level Curves to Some Problems on Algebraic Surfaces

abstract:
  In a previous work of the authors, a result to algorithmically compute the
topology types of the level curves of an algebraic surface, is given. From this
result, here we derive applications based on level curves to determine some
topological features of surfaces (reality, compactness, connectivity) and to
the problem of plotting.


title: Roadmap for ILC Detector R&D Test Beams

abstract:
  This document provides a roadmap for ILC detector test beam needs in the next
3 - 5 years. In this period, detector Letters of Intent are expected by fall
2008, the ILC Engineering Design Report to be submitted in ILC and its
detectors in 2012. ILC detectors are required to have unprecedented precision
to be able to elucidate new physics discoveries at TeV energies from the LHC
and ILC machines, and to fully exploit experimental investifation at the
electrweak unification energy scale. Ahieving this requires significant
investment for detector test beam activities to complete the R&D needed, to
test prototypes and (later) to qualify final detector system desgns, including
integated system tess. This roadmap document describes the need for significant
increases in resources for ILC test beam activities. It should be used by test
beam facility managers and the worldwide ILC leadership to assure that the
necessary resources and facilities are made available to meet the needs in
time.


title:
Exact-exchange energy density in the gauge of a semilocal density
  functional approximation

abstract:
  Exact-exchange energy density and energy density of a semilocal density
functional approximation are two key ingredients for modeling the static
correlation, a strongly nonlocal functional of the density, through a local
hybrid functional. Because energy densities are not uniquely defined, the
conventional (Slater) exact-exchange energy density
$e_\mathrm{x}^\mathrm{ex(conv)}$ is not necessarily well-suited for local
mixing with a given semilocal approximation. We show how to transform
$e_\mathrm{x}^\mathrm{ex(conv)}$ in order to make it compatible with an
arbitrary semilocal density functional, taking the nonempirical
meta-generalized gradient approximation of Tao, Perdew, Staroverov, and
Scuseria (TPSS) as an example. Our additive gauge transformation function
integrates to zero, satisfies exact constraints, and is most important where
the density is dominated by a single orbital shape. We show that, as expected,
the difference between semilocal and exact-exchange energy densities becomes
more negative under bond stretching in He$_2^{+}$ and related systems. Our
construction of $e_\mathrm{x}^\mathrm{ex(conv)}$ by a
resolution-of-the-identity method requires uncontracted basis functions.


title: Lensing Systematics from Space: Modeling PSF effects in the SNAP survey

abstract:
  Anisotropy in the point spread function (PSF) contributes a systematic error
to weak lensing measurements. In this study we use a ray tracer that
incorporates all the optical elements of the SNAP telescope to estimate this
effect. Misalignments in the optics generates PSF anisotropy, which we
characterize by its ellipticity. The effect of three time varying effects:
thermal drift, guider jitter, and structural vibration on the PSF are estimated
for expected parameters of the SNAP telescope. Multiple realizations of a
thousand square degree mock survey are then generated to include the systematic
error pattern induced by these effects. We quantify their contribution to the
power spectrum of the lensing shear. We find that the dominant effect comes
from the thermal drift, which peaks at angular wavenumbers l ~ 10^3, but its
amplitude is over one order of magnitude smaller than the size of the expected
statistical error. While there are significant uncertainties in our modeling,
our study indicates that time-varying PSFs will contribute at a smaller level
than statistical errors in SNAP's weak lensing measurements.


title: Freyd's generating hypothesis for groups with periodic cohomology

abstract:
  Let $G$ be a finite group and let $k$ be a field whose characteristic $p$
divides the order of $G$. Freyd's generating hypothesis for the stable module
category of $G$ is the statement that a map between finite-dimensional
$kG$-modules in the thick subcategory generated by $k$ factors through a
projective if the induced map on Tate cohomology is trivial. We show that if
$G$ has periodic cohomology then the generating hypothesis holds if and only if
the Sylow $p$-subgroup of $G$ is $C_2$ or $C_3$. We also give some other
conditions that are equivalent to the GH for groups with periodic cohomology.


title: Riemann surfaces and AF-algebras

abstract:
  For a generic set in the Teichmueller space, we construct a covariant functor
with the range in a category of the AF-algebras; the functor maps isomorphic
Riemann surfaces to the stably isomorphic AF-algebras. As a special case, one
gets a categorical correspondence between complex tori and the so-called
Effros-Shen algebras.


title: A counter-example to the Andreotti-Grauert conjecture

abstract:
  Let $X$ be an analytic complex space which is $q$-complete. Then it follows
from a theorem of Andreotti-Grauert [1] that $H^{p}(X, {\mathcal{F}})=0$ for
every coherent analytic sheaf ${\mathcal{F}}$ on $X$ if $p\geq q$. Until now it
is not known if these two conditions are equivalent. The aim of this article is
to give a counterexample to the converse of this statement. We show that there
exist for each $n\geq 3$ open sets $\Omega\subset\complexes^{n}$ such that
$H^{n-1}(\Omega, {\mathcal{F}})=0$ for every ${\mathcal{F}}\in coh(\Omega)$ but
$\Omega$ is not $(n-1)$-complete.


title: Generation of Magnetic Field by Combined Action of Turbulence and Shear

abstract:
  The feasibility of a mean-field dynamo in nonhelical turbulence with
superimposed linear shear is studied numerically in elongated shearing boxes.
Exponential growth of magnetic field at scales much larger than the outer scale
of the turbulence is found. The charateristic scale of the field is l_B ~
S^{-1/2} and growth rate is gamma ~ S, where S is the shearing rate. This newly
discovered shear dynamo effect potentially represents a very generic mechanism
for generating large-scale magnetic fields in a broad class of astrophysical
systems with spatially coherent mean flows.

categories: astro-ph nlin.CD physics.flu-dyn physics.plasm-ph


title:
Detailed magnetization study of superconducting properties of YBCO
  ceramic spheres

abstract:
  We present a magnetization study of low density YBCO ceramics carried out in
magnetic fields 0.5 Oe < H < 50 kOe. It was demonstrated that superconducting
links between grains may be completely suppressed either by a magnetic field of
the order of 100 Oe (at low temperatures) or by an increase of temperature
above 70 K. This property of present samples allowed to evaluate the ratio
between an average grain size and the magnetic field penetration depth lambda.
Furthermore, at temperatures T > 85 K, using low-field magnetization
measurements, we could evaluate the temperature dependence of lambda, which
turned out to be very close to predictions of the conventional Ginzburg-Landau
theory. Although present samples consisted of randomly oriented grains,
specifics of magnetization measurements allowed for evaluation of lambda_ab(T).
Good agreement between our estimation of the grain size with the real sample
structure provides evidence for the validity of this analysis of magnetization
data. Measurements of equilibrium magnetization in high magnetic fields were
used for evaluation of Hc2(T). At temperatures close to T_c, the Hc2(T)
dependence turned out to be linear in agreement with the Ginzburg-Landau
theory. The value of temperature, at which Hc2 vanishes, coincides with the
superconducting critical temperature evaluated from low-field measurements.


title: Final results on nu_mu to nu_tau oscillation from the CHORUS experiment

abstract:
  The final oscillation analysis of the complete set of data collected by
CHORUS in the years 1994--1997 is presented. Reconstruction algorithms of data
extracted by electronic detectors were improved and the data recorded in the
emulsion target were analysed by new automated scanning systems, allowing the
use of a new method for event reconstruction in emulsion. CHORUS has applied
these new techniques to the sample of 1996--1997 events for which no muons were
observed in the electronic detectors. Combining the new sample with the data
analysed in previous papers, the overall sensitivity of the experiment to the
$\nu_\tau$ appearance is thus improved. In a two-neutrino mixing scheme, a 90%
C.L. upper limit of $\sin^2 2\theta_{\mu\tau} < 4.4 \times 10^{-4}$ is set for
large $\Delta m^2$, improving by a factor 1.5 the previously published CHORUS
result.


title: Scale-renormalized matrix-product states for correlated quantum systems

abstract:
  A generalization of matrix product states (MPS) is introduced which is
suitable for describing interacting quantum systems in two and three
dimensions. These scale-renormalized matrix-product states (SR-MPS) are based
on a course-graining of the lattice in which the blocks at each level are
associated with matrix products that are further transformed (scale
renormalized) with other matrices before they are assembled to form blocks at
the next level. Using variational Monte Carlo simulations of the
two-dimensional transverse-field Ising model as a test, it is shown that the
SR-MPS converge much more rapidly with the matrix size than a standard MPS. It
is also shown that the use of lattice-symmetries speeds up the convergence very
significantly.


title:
Using X-ray observations to identify the particle acceleration
  mechanisms in VHE SNRs and "dark" VHE sources

abstract:
  Very high energy (VHE) gamma-ray observations have proven to be very
successful in localizing Galactic acceleration sites of VHE particles.
Observations of shell-type supernova remnants have confirmed that particles are
accelerated to VHE energies in supernova blast waves; the interpretation of the
gamma-ray data in terms of hadronic or leptonic particle components in these
objects relies nevertheless strongly on input from X-ray observations. The
largest identified Galactic VHE source class consists of pulsar wind nebulae,
as detected in X-rays. Many of the remaining VHE sources remain however
unidentified until now. With X-ray observations of these enigmatic "dark"
objects one hopes to solve the following questions: What is the astrophysical
nature of these sources? Are they predominantly electron or hadron
accelerators? And what is their contribution to the overall cosmic ray energy
budget? The paper aims to provide an overview over the identification status of
the Galactic VHE source population.


title:
Spectral properties of the nonspherically decaying radiation generated
  by a rotating superluminal source

abstract:
  The focusing of the radiation generated by a polarization current with a
superluminally rotating distribution pattern is of a higher order in the plane
of rotation than in other directions. Consequently, our previously published
asymptotic approximation to the value of this field outside the equatorial
plane breaks down as the line of sight approaches a direction normal to the
rotation axis, i.e., is nonuniform with respect to the polar angle. Here we
employ an alternative asymptotic expansion to show that, though having a rate
of decay with frequency (mu) that is by a factor of order mu^(2/3) slower, the
equatorial radiation field has the same dependence on distance as the
nonspherically decaying component of the generated field in other directions:
it, too, diminishes as the inverse square root of the distance from its source.
We also briefly discuss the relevance of these results to the giant pulses
received from pulsars: the focused, nonspherically decaying pulses that arise
from a superluminal polarization current in a highly magnetized plasma have a
power-law spectrum (i.e., a flux density proportional to mu^alpha) whose index
(alpha) is given by one of the values -2/3, -2, -8/3, or -4.


title:
Singular Yamabe metrics and initial data with exactly
  Kottler-Schwarzschild-de Sitter ends

abstract:
  We construct large families of initial data sets for the vacuum Einstein
equations with positive cosmological constant which contain exactly Delaunay
ends; these are non-trivial initial data sets which coincide with those for the
Kottler-Schwarzschild-de Sitter metrics in regions of infinite extent. From the
purely Riemannian geometric point of view, this produces complete, constant
positive scalar curvature metrics with exact Delaunay ends which are not
globally Delaunay. The ends can be used to construct new compact initial data
sets via gluing constructions. The construction provided applies to more
general situations where the asymptotic geometry may have non-spherical
cross-sections consisting of Einstein metrics with positive scalar curvature.


title: From Quark-Gluon Plasma to the Perfect Liquid

abstract:
  After reviewing some basic concepts of the theory of strongly interacting
matter above nuclear energy density and reviewing some salient results of the
experimental program at the Relativistic Heavy Ion Collider (RHIC), these
lectures explain why the quark-gluon plasma observed in the RHIC experiments
has been called a ``perfect liquid.'' They then give an introduction to some
recent ideas concerning the possible origin of the nearly inviscid nature of
the quark-gluon plasma and discuss the connection between low viscosity and
strong parton energy loss of hot QCD matter.


title: Schiff Theorem Revisited

abstract:
  We carefully rederive the Schiff theorem and prove that the usual expression
of the Schiff moment operator is correct and should be applied for calculations
of atomic electric dipole moments. The recently discussed corrections to the
definition of the Schiff moment are absent.


title: Local power fluctuations in two-dimensional turbulence

abstract:
  The statistics of power fluctuations are studied in simulations of
two-dimensional turbulence in both inverse (energy) and direct (enstrophy)
cascade regimes from both Lagrangian and Eulerian perspectives. The probability
density function (PDF) of the appropriately defined dimensionless power is
strongly non-gaussian with asymmetric exponential tails. This distribution can
be modeled by the distribution of the product of correlated normal variables
allowing a derivation of the asymptotics of the tails. The PDF of the
dimensionless power is shown to exhibit an empirical Fluctuation Relation. An
expression for the entropy production rate is deduced from the asymptotic form
of the power PDF and is found to agree very well with the measured entropy
rate.


title: Multi-Fluid Simulation of the Magnetic Field Evolution in Neutron Stars

abstract:
  Using a numerical simulation, we study the effects of ambipolar diffusion and
ohmic diffusion on the magnetic field evolution in the interior of an isolated
neutron star. We are interested in the behavior of the magnetic field on a long
time scale, over which all Alfven and sound waves have been damped. We model
the stellar interior as an electrically neutral plasma composed of neutrons,
protons and electrons, which can interact with each other through collisions
and electromagnetic forces. Weak interactions convert neutrons and charged
particles into each other, erasing chemical imbalances. As a first step, we
assume that the magnetic field points in one fixed Cartesian direction but can
vary along an orthogonal direction. We start with a uniform-density background
threaded by a homogeneous magnetic field and study the evolution of a magnetic
perturbation as well as the density fluctuations it induces in the particles.
We show that the system evolves through different quasi-equilibrium states and
estimate the characteristic time scales on which these quasi-equilibria occur.


title:
The effect of 3He impurities on the nonclassical response to oscillation
  of solid 4He

abstract:
  We have investigated the influence of impurities on the possible supersolid
transition by systematically enriching isotopically-pure 4He (< 1 ppb of 3He)
with 3He. The onset of nonclassical rotational inertia is broadened and shifts
monotonically to higher temperature with increasing 3He concentration,
suggesting that the phenomenon is correlated to the condensation of 3He atoms
onto the dislocation network in solid 4He.


title:
Segregation process and phase transition in cyclic predator-prey models
  with even number of species

abstract:
  We study a spatial cyclic predator-prey model with an even number of species
(for n=4, 6, and 8) that allows the formation of two defective alliances
consisting of the even and odd label species. The species are distributed on
the sites of a square lattice. The evolution of spatial distribution is
governed by iteration of two elementary processes on neighboring sites chosen
randomly: if the sites are occupied by a predator-prey pair then the predator
invades the prey's site; otherwise the species exchange their site with a
probability $X$. For low $X$ values a self-organizing pattern is maintained by
cyclic invasions. If $X$ exceeds a threshold value then two types of domains
grow up that formed by the odd and even label species, respectively. Monte
Carlo simulations indicate the blocking of this segregation process within a
range of X for n=8.


title: Non-linearizable Actions of Commutative Reductive Groups

abstract:
  We generalize a construction of Freudenburg and Moser-Jauslin in order to
obtain an example of a non-linearizable action of a commutative reductive
algebraic group on the affine space for every field of characteristic zero
which admits a quadratic field extension.


title: Driven Intrinsic Localized Modes in a Coupled Pendulum Array

abstract:
  Intrinsic localized modes (ILMs), also called discrete breathers, are
directly generated via modulational instability in an array of coupled
pendulums. These ILMs can be stabilized over a range of driver frequencies and
amplitudes. They are characterized by a pi-phase difference between their
center and wings. At higher driver frequencies, these ILMs are observed to
disintegrate via a pulsating instability, and the mechanism of this breather
instability is investigated.


title: An arithmetic Riemann-Roch theorem for pointed stable curves

abstract:
  We prove an arithmetic Riemann-Roch theorem for pointed stable curves. We
derive consequences for the Selberg zeta function of an open modular curve
$Y_{1}(p)$ (resp. $Y_{0}(p)$), for a prime number $p\geq 11$ (resp. congruent
to 11 modulo 12).


title:
On the Capacity of Interference Channels with One Cooperating
  Transmitter

abstract:
  Inner and outer bounds are established on the capacity region of two-sender,
two-receiver interference channels where one transmitter knows both messages.
The transmitter with extra knowledge is referred to as being cognitive. The
inner bound is based on strategies that generalize prior work, and include
rate-splitting, Gel'fand-Pinsker coding and cooperative transmission. A general
outer bound is based on the Nair-El Gamal outer bound for broadcast channels. A
simpler bound is presented for the case in which one of the decoders can decode
both messages. The bounds are evaluated and compared for Gaussian channels.


title: Superfluid density of superconductor-ferromagnet bilayers

abstract:
  We report the first measurements of the effective superfluid density n_S(T)
\propto \lambda^{-2}(T) of Superconductor-Ferromagnet (SC/FM) bilayers, where
\lambda is the effective magnetic field penetration depth. Thin Nb/Ni bilayers
were sputtered in ultrahigh vacuum in quick succession onto oxidized Si
substrates. Nb layers are 102 A thick for all samples, while Ni thicknesses
vary from 0 to 100 A. T_C determined from \lambda^{-2}(T) decreases rapidly as
Ni thickness d_Ni increases from zero to 15 A, then it has a shallow minimum at
d_Ni \approx 25 A. \lambda^{-2}(0) behaves similarly, but has a minimum several
times deeper. In fact, \lambda^{-2}(0) continues to increase with increasing Ni
thickness long after T_C has stopped changing. We argue that this indicates a
substantial superfluid density inside the ferromagnetic Ni films.


title: Transient Random Walks in Random Environment on a Galton-Watson Tree

abstract:
  We consider a transient random walk $(X_n)$ in random environment on a
Galton--Watson tree. Under fairly general assumptions, we give a sharp and
explicit criterion for the asymptotic speed to be positive. As a consequence,
situations with zero speed are revealed to occur. In such cases, we prove that
$X_n$ is of order of magnitude $n^{\Lambda}$, with $\Lambda \in (0,1)$. We also
show that the linearly edge reinforced random walk on a regular tree always has
a positive asymptotic speed, which improves a recent result of Collevecchio
\cite{Col06}.


title: Simu-LC : a Light-Curve simulator for CoRoT

abstract:
  Simulating the data that a space instrument like COROT will provide might
look presomptuous. Indeed, it is certainly, when comparing to previous
comparable instruments like IPHIR or GOLF. These two examples show that the
nominal behaviour of the instrument is not always reached, but this does not
prevent this instrument to provide very interesting data. However, despite some
technical problems, IPHIR and GOLF yielded a wealth of scientific results.
Thus, what is the interest of simulating COROT data? How close to reality these
simualtions will get? This might not be the most important fact as the
preparation of these simulations will help us to prepare the analysis of real
data and to be ready in case of unexpected technical behaviour of the
instrument perturbating the data, or unexpected physical behaviour of the
targets of the instrument. A consequence of that is that the simulation tool
must include technical and physical aspects, making the task even more
difficult. These aspects cover: photon noise, p modes excitation, granulation
signal, stellar activity signal, orbital perturbations, stellar rotation...
  The software presented here is freely available at:
http://www.lesia.obspm.fr/~corotswg/simulightcurve.html


title:
Asymptotic description of solitary wave trains in fully nonlinear
  shallow-water theory

abstract:
  We derive an asymptotic formula for the amplitude distribution in a fully
nonlinear shallow-water solitary wave train which is formed as the long-time
outcome of the initial-value problem for the Su-Gardner (or one-dimensional
Green-Naghdi) system. Our analysis is based on the properties of the
characteristics of the associated Whitham modulation system which describes an
intermediate "undular bore" stage of the evolution. The resulting formula
represents a "non-integrable" analogue of the well-known semi-classical
distribution for the Korteweg-de Vries equation, which is usually obtained
through the inverse scattering transform. Our analytical results are shown to
agree with the results of direct numerical simulations of the Su-Gardner
system. Our analysis can be generalised to other weakly dispersive, fully
nonlinear systems which are not necessarily completely integrable.


title: CNI polarimetry with Helium 3

abstract:
  By making use of previous analysis of CNI for pp and pC scattering, the
spin-flip factor for np scattering is determined as a function of energy and
then used to calculate the p He3 asymmetry A_N(s)' arising in p He 3 elastic
scattering. It is found to be comparable to A_N(s) for pp scattering, but of
the opposite sign. It seems that this method could be a practical for measuring
the polarization of a He3 beam.


title: An X-ray emitting black hole in a globular cluster

abstract:
  We present optical and X-ray data for the first object showing strong
evidence for being a black hole in a globular cluster. We show the initial
X-ray light curve and X-ray spectrum which led to the discovery that this is an
extremely bright, highly variable source, and thus must be a black hole. We
present the optical spectrum which unambiguously identifies the optical
counterpart as a globular cluster, and which shows a strong, broad [O III]
emission line, most likely coming from an outflow driven by the accreting
source.


title:
Electron spin relaxation via flexural phonon modes in semiconducting
  carbon nanotubes

abstract:
  This work considers the g-tensor anisotropy induced by the flexural thermal
vibrations in one-dimensional structures and its role in electron spin
relaxation. In particular, the mechanism of spin-lattice relaxation via
flexural modes is studied theoretically for localized and delocalized
electronic states in semiconducting carbon nanotubes in the presence of
magnetic field. The calculation of one-phonon spin-flip process predicts
distinctive dependencies of the relaxation rate on temperature, magnetic field
and nanotube diameter. Comparison with the spin relaxation caused by the
hyperfine interaction clearly suggests the relative efficiency of the proposed
mechanism at sufficiently high temperatures. Specifically, the longitudinal
spin relaxation time in the semiconducting carbon nanotubes is estimated to be
as short as 30 microseconds at room temperature.


title:
Simultaneous Multi-Wavelength Observations of Magnetic Activity in
  Ultracool Dwarfs. II. Mixed Trends in VB10 and LSR1835+32 and the Possible
  Role of Rotation

abstract:
  [Abridged] As part of our on-going investigation of magnetic activity in
ultracool dwarfs we present simultaneous radio, X-ray, UV, and optical
observations of LSR1835+32 (M8.5), and simultaneous X-ray and UV observations
of VB10 (M8), both with a duration of about 9 hours. LSR1835+32 exhibits
persistent radio emission and H-alpha variability on timescales of ~0.5-2 hr.
The detected UV flux is consistent with photospheric emission, and no X-ray
emission is detected to a deep limit of L_X/L_bol<10^-5.7. The H-alpha and
radio emission are temporally uncorrelated, and the ratio of radio to X-ray
luminosity exceeds the correlation seen in F-M6 stars by >2x10^4. Similarly,
L_Halpha/L_X>10 is at least 30 times larger than in early M dwarfs, and
eliminates coronal emission as the source of chromospheric heating. The lack of
radio variability during four rotations of LSR1835+32 requires a uniform
stellar-scale field of ~10 G, and indicates that the H-alpha variability is
dominated by much smaller scales, <10% of the chromospheric volume. VB10, on
the other hand, shows correlated flaring and quiescent X-ray and UV emission,
similar to the behavior of early M dwarfs. Delayed and densely-sampled optical
spectra exhibit a similar range of variability amplitudes and timescales to
those seen in the X-rays and UV, with L_Halpha/L_X~1. Along with our previous
observations of the M8.5 dwarf TVLM513-46546 we conclude that late M dwarfs
exhibit a mix of activity patterns, which points to a transition in the
structure and heating of the outer atmosphere by large-scale magnetic fields.
We find that rotation may play a role in generating the fields as evidenced by
a tentative correlation between radio activity and rotation velocity. The X-ray
emission, however, shows evidence for super-saturation at vsini>25 km/s.


title:
Spitzer Constraints on the Stellar Populations of Lyman-Alpha Emitting
  Galaxies at z = 3.1

abstract:
  We investigate the stellar populations of a sample of 162 Lyman-alpha
emitting galaxies (LAEs) at z = 3.1 in the Extended Chandra Deep Field South,
using deep Spitzer IRAC data available from the GOODS and SIMPLE surveys to
derive reliable stellar population estimates. We divide the LAEs according to
their rest-frame near-IR luminosities into IRAC-detected and IRAC-undetected
samples. About 70% of the LAEs are undetected in 3.6 micron down to [3.6] =
25.2 AB. Stacking analysis reveals that the average stellar population of the
IRAC-undetected sample has an age of ~ 200 Myr and a mass of ~ 3x10^8 solar
masses, consistent with the expectation that LAEs are mostly young and low-mass
galaxies. On the other hand, the IRAC-detected LAEs are on average
significantly older and more massive, with an average age > 1 Gyr and mass ~
10^10 solar masses. Comparing the IRAC colors and magnitudes of the LAEs to z ~
3 Lyman break galaxies (LBGs) shows that the IRAC-detected LAEs lie at the
faint blue end of the LBG color-magnitude distribution, suggesting that
IRAC-detected LAEs may be the low mass extension of the LBG population. We also
present tentative evidence for a small fraction (~ 5%) of obscured AGN within
the LAE sample. Our results suggest that LAEs posses a wide range of ages and
masses. Additionally, the presence of evolved stellar populations inside LAEs
suggests that the Lyman-alpha luminous phase of galaxies may either be a
long-lasting or recurring phenomenon.


title: Molecular Recollision Interferometry in High Harmonic Generation

abstract:
  We use extreme-ultraviolet interferometry to measure the phase of high-order
harmonic generation from transiently aligned CO2 molecules. We unambiguously
observe a reversal in phase of the high order harmonic emission for higher
harmonic orders with a sufficient degree of alignment. This results from
molecular-scale quantum interferences between the molecular electronic wave
function and the recolliding electron as it recombines with the molecule, and
is consistent with a two-center model. Furthermore, using the combined harmonic
intensity and phase information, we extract accurate information on the
dispersion relation of the returning electron wavepacket as a function of
harmonic order. This analysis shows evidence of the effect of the molecular
potential on the recolliding electron wave.


title: Priority diffusion model in lattices and complex networks

abstract:
  We introduce a model for diffusion of two classes of particles ($A$ and $B$)
with priority: where both species are present in the same site the motion of
$A$'s takes precedence over that of $B$'s. This describes realistic situations
in wireless and communication networks. In regular lattices the diffusion of
the two species is normal but the $B$ particles are significantly slower, due
to the presence of the $A$ particles. From the fraction of sites where the $B$
particles can move freely, which we compute analytically, we derive the
diffusion coefficients of the two species. In heterogeneous networks the
fraction of sites where $B$ is free decreases exponentially with the degree of
the sites. This, coupled with accumulation of particles in high-degree nodes
leads to trapping of the low priority particles in scale-free networks.


title: Energy Dependence of the Delta Resonance: Chiral Dynamics in Action

abstract:
  There is an important connection between the low energy theorems of QCD and
the energy dependence of the Delta resonance in pi-N scattering, as well as the
closely related gamma^{*} N -> pi N reaction. The resonance shape is due not
only to the strong pi-N interaction in the p wave but the small interaction in
the s wave; the latter is due to spontaneous chiral symmetry breaking in QCD
(i.e. the Nambu-Goldstone nature of the pion). A brief overview of experimental
tests of chiral perturbation theory and chiral based models is presented


title: On the terminal velocity of sedimenting particles in a flowing fluid

abstract:
  The influence of an underlying carrier flow on the terminal velocity of
sedimenting particles is investigated both analytically and numerically. Our
theoretical framework works for a general class of (laminar or turbulent)
velocity fields and, by means of an ordinary perturbation expansion at small
Stokes number, leads to closed partial differential equations (PDE) whose
solutions contain all relevant information on the sedimentation process. The
set of PDE's are solved by means of direct numerical simulations for a class of
2D cellular flows (static and time dependent) and the resulting phenomenology
is analysed and discussed.


title: Positivity of Tur\'an determinants for orthogonal polynomials

abstract:
  The orthogonal polynomials $p_n$ satisfy Tur\'an's inequality if
$p_n^2(x)-p_{n-1}(x)p_{n+1}(x)\ge 0$ for $n\ge 1$ and for all $x$ in the
interval of orthogonality. We give general criteria for orthogonal polynomials
to satisfy Tur\'an's inequality. This yields the known results for classical
orthogonal polynomials as well as new results, for example, for the
$q$--ultraspherical polynomials.


title:
Efficient algorithms for rigid body integration using optimized
  splitting methods and exact free rotational motion

abstract:
  Hamiltonian splitting methods are an established technique to derive stable
and accurate integration schemes in molecular dynamics, in which additional
accuracy can be gained using force gradients. For rigid bodies, a tradition
exists in the literature to further split up the kinetic part of the
Hamiltonian, which lowers the accuracy. The goal of this note is to comment on
the best combination of optimized splitting and gradient methods that avoids
splitting the kinetic energy. These schemes are generally applicable, but the
optimal scheme depends on the desired level of accuracy. For simulations of
liquid water it is found that the velocity Verlet scheme is only optimal for
crude simulations with accuracies larger than 1.5%, while surprisingly a
modified Verlet scheme (HOA) is optimal up to accuracies of 0.4% and a fourth
order gradient scheme (GIER4) is optimal for even higher accuracies.


title: Calabi-Yau Frobenius algebras

abstract:
  We define Calabi-Yau and periodic Frobenius algebras over arbitrary base
commutative rings. We define a Hochschild analogue of Tate cohomology, and show
that the "stable Hochschild cohomology" of periodic CY Frobenius algebras has a
Batalin-Vilkovisky and Frobenius algebra structure. Such algebras include
(centrally extended) preprojective algebras of (generalized) Dynkin quivers,
and group algebras of classical periodic groups. We use this theory to compute
(for the first time) the Hochschild cohomology of many algebras related to
quivers, and to simplify the description of known results. Furthermore, we
compute the maps on cohomology from extended Dynkin preprojective algebras to
the Dynkin ones, which relates our CY property (for Frobenius algebras) to that
of Ginzburg (for algebras of finite Hochschild dimension).


title: Differential operators and BV structures in noncommutative geometry

abstract:
  We introduce a new formalism of differential operators for a general
associative algebra A. It replaces Grothendieck's notion of differential
operator on a commutative algebra in such a way that derivations of the
commutative algebra are replaced by DDer(A), the bimodule of double
derivations. Our differential operators act not on the algebra A itself but
rather on F(A), a certain `Fock space' associated to any noncommutative algebra
A in a functorial way. The corresponding algebra D(F(A)), of differential
operators, is filtered and gr D(F(A)), the associated graded algebra, is
commutative in some `twisted' sense. The resulting double Poisson structure on
gr D(F(A)) is closely related to the one introduced by Van den Bergh.
Specifically, we prove that gr D(F(A))=F(T_A(DDer(A)), provided A is smooth.
  It is crucial for our construction that the Fock space F(A) carries an
extra-structure of a wheelgebra, a new notion closely related to the notion of
a wheeled PROP. There are also notions of Lie wheelgebras, and so on. In that
language, D(F(A)) becomes the universal enveloping wheelgebra of a Lie
wheelgebroid of double derivations.
  In the second part of the paper we show, extending a classical construction
of Koszul to the noncommutative setting, that any Ricci-flat, torsion-free
bimodule connection on DDer(A) gives rise to a second order (wheeled)
differential operator, a noncommutative analogue of the BV-operator.


title: Search for New Physics with Photons at the Tevatron

abstract:
  We report on a search for compositeness in ee+gamma events and a search for
gauge-mediated supersymmetry in gamma+gamma+met events. We also report on two
signature-based searches for anomalous production of gamma + gamma + X (where
X=e, mu, gamma, met) and gamma + lepton + X. The analyses are based on 0.9--1.2
fb-1 of data from p-pbar collisions at sqrt(s)=1.96 TeV collected with the CDF
and D0 detectors at the Fermilab Tevatron. No significant excess of data over
the predicted background has been observed.


title:
On the systematics of asteroseismological mass determinations of PG1159
  stars

abstract:
  We analyze systematics in the asteroseismological mass determination methods
in pulsating PG 1159 stars. We compare the seismic masses resulting from the
comparison of the observed mean period spacings with the usually adopted
asymptotic period spacings, and the average of the computed period spacings.
Computations are based on full PG1159 evolutionary models with stellar masses
ranging from 0.530 to 0.741 Mo that take into account the complete evolution of
progenitor stars. We conclude that asteroseismology is a precise and powerful
technique that determines the masses to a high internal accuracy, but it
depends on the adopted mass determination method. In particular, we find that
in the case of pulsating PG 1159 stars characterized by short pulsation
periods, like PG 2131+066 and PG 0122+200, the employment of the asymptotic
period spacings overestimates the stellar mass by about 0.06 Mo as compared
with inferences from the average of the period spacings. In this case, the
discrepancy between asteroseismological and spectroscopical masses is markedly
reduced when use is made of the mean period spacing instead of the asymptotic
period spacing.


title: If LHC is a Mini-Time-Machines Factory, Can We Notice?

abstract:
  Assuming the hypothesis of TeV-scale multi-dimensional gravity, one can
imagine that at LHC not only mini-black-holes (MBH) will be intensively
created, but also other exotic gravitational configurations, including
hypothetical mini-time-machines (MTM). Like MBH, they should quickly evaporate,
but one can wonder if their temporal existence at the moment of high-energy
collision can leave any traces in the observable data. We briefly discuss five
thinkable effects: (i) change of the energy spectrum due to the
frequency-filtration property of MTM, (ii) possible production of anomalously
energetic particles, accelerated by passing many times through gravitational
field inside the MTM, (iii) acceleration of particle decays, since the proper
time of a particle moving inside MTM can strongly exceed the laboratory time,
(iv) CPT and naive unitarity violation (thermalization) due to effective
non-local interactions caused by MTM and to possible ambiguity in the
population of closed world-lines inside MTM, (v) collective effects due to
conversion of a single particle into a bunch of its co-existing copies within
the MTM. Despite possible particle-antiparticle conversion inside MTM, they do
not seem to produce any specific CP-violation effects.