title:
On the Real Analyticity of the Scattering Operator for the Hartree
  Equation

abstract:
  In this paper, we study the real analyticity of the scattering operator for
the Hartree equation $ i\partial_tu=-\Delta u+u(V*|u|^2)$. To this end, we
exploit interior and exterior cut-off in time and space, and combining with the
compactness argument to overcome difficulties which arise from absence of good
properties for the nonlinear Klein-Gordon equation, such as the finite speed of
propagation and ideal time decay estimate. Additionally, the method in this
paper allows us to simplify the proof of analyticity of the scattering operator
for the nonlinear Klein-Gordon equation with cubic nonlinearity in Kumlin.


title:
Interacion of Heavy Metal Ions with C-Phycocyanin: Binding Isotherms and
  Cooperative Effects

abstract:
  The binding constant of copper(II) ions to C-PC were determined at different
ionic strengths from binding isotherms by equilibrium dialysis and flame atomic
absorption spectroscopy. Fluorescence and absorbtion spectroscopy provides
insight of metal-C-phycocyanin interactions. Fluorescence measurements
demonstrate C-PC quenching of heavy metal ions emission intensities.
Stern-Volmer quenching constants were obtained from the linear quenching plots.
Blue shifts in the fluorescence spectra were observed during metal binding to
C-PC. It was shown, that between bound metal ions in C-PC there exists positive
cooperativity.


title: Black-Body Anomaly: Analysis of Temperature Offsets

abstract:
  Based on the postulate that photon propagation is governed by a dynamically
broken SU(2) gauge symmetry (scale $\sim 10^{-4} $eV) we make predictions for
temperature offsets due to a low-temperature (a few times the present CMB
temperature) spectral anomaly at low frequencies. Temperature offsets are
extracted from least-square fits of the anomalous black-body spectra to their
conventional counterparts. We discuss statistical errors, compare our results
with those obtained from calibration data of the FIRAS instrument, and point
out that our predicted offsets are screened by experimental errors given the
frequency range used by FIRAS to perform their spectral fits. We also make
contact with the WMAP observation by blueshifting their frequency bands.
Although our results hint towards a strong dynamical component in the CMB
dipole and an explanation of low-$l$ suppression it is important in view of its
particle-physics implications that the above postulate be verified/falsified by
an independent low-temperature black-body precision experiment.


title: Mixing in massive stellar mergers

abstract:
  The early evolution of dense star clusters is possibly dominated by close
interactions between stars, and physical collisions between stars may occur
quite frequently. Simulating a stellar collision event can be an intensive
numerical task, as detailed calculations of this process require hydrodynamic
simulations in three dimensions. We present a computationally inexpensive
method in which we approximate the merger process, including shock heating,
hydrodynamic mixing and mass loss, with a simple algorithm based on
conservation laws and a basic qualitative understanding of the hydrodynamics of
stellar mergers. The algorithm relies on Archimedes' principle to dictate the
distribution of the fluid in the stable equilibrium situation. We calibrate and
apply the method to mergers of massive stars, as these are expected to occur in
young and dense star clusters. We find that without the effects of microscopic
mixing, the temperature and chemical composition profiles in a collision
product can become double-valued functions of enclosed mass. Such an unphysical
situation is mended by simulating microscopic mixing as a post-collision
effect. In this way we find that head-on collisions between stars of the same
spectral type result in substantial mixing, while mergers between stars of
different spectral type, such as type B and O stars ($\sim$10 and $\sim$40\msun
respectively), are subject to relatively little hydrodynamic mixing.


title:
Shape dynamics during deposit of simple metal clusters on rare gas
  matrices

abstract:
  Using a combined quantum mechanical/classical method, we study the collisions
of small Na clusters on large Ar clusters as a model for cluster deposit. We
work out basic mechanisms by systematic variation of collision energy, system
sizes, and orientations. The soft Ar material is found to serve as an extremely
efficient shock absorber. The collisional energy is quickly transfered at first
impact and the Na clusters are always captured by the Ar surface. The
distribution of the collision energy into the Ar system proceeds very fast with
velocity of sound. The relaxation of shapes goes at a slower pace using times
of several ps. It produces a substantial rearrangement of the Ar system while
the Na cluster remains rather robust.


title: Integral Concentration of idempotent trigonometric polynomials with gaps

abstract:
  We prove that for all p>1/2 there exists a constant $\gamma_p>0$ such that,
for any symmetric measurable set of positive measure $E\subset \TT$ and for any
$\gamma<\gamma_p$, there is an idempotent trigonometrical polynomial f
satisfying $\int_E |f|^p > \gamma \int_{\TT} |f|^p$. This disproves a
conjecture of Anderson, Ash, Jones, Rider and Saffari, who proved the existence
of $\gamma_p>0$ for p>1 and conjectured that it does not exists for p=1.
  Furthermore, we prove that one can take $\gamma_p=1$ when p>1 is not an even
integer, and that polynomials f can be chosen with arbitrarily large gaps when
$p\neq 2$. This shows striking differences with the case p=2, for which the
best constant is strictly smaller than 1/2, as it has been known for twenty
years, and for which having arbitrarily large gaps with such concentration of
the integral is not possible, according to a classical theorem of Wiener.
  We find sharper results for $0<p\leq 1$ when we restrict to open sets, or
when we enlarge the class of idempotent trigonometric polynomials to all
positive definite ones.


title: Viability of Dirac phase leptogenesis

abstract:
  We discuss the conditions for a non-vanishing Dirac phase \delta and mixing
angle \theta_{13}, sources of CP violation in neutrino oscillations, to be
uniquely responsible for the observed matter-antimatter asymmetry of the
universe through leptogenesis. We show that this scenario, that we call
\delta-leptogenesis, is viable when the degenerate limit (DL) for the heavy
right-handed (RH) neutrino spectrum is considered. We derive an interesting
joint condition on \sin\theta_{13} and the absolute neutrino mass scale that
can be tested in future neutrino oscillation experiments. In the limit of
hierarchical heavy RH neutrino spectrum (HL), we strengthen the previous result
that \delta-leptogenesis is only very marginally allowed, even when the
production from the two heavier RH neutrinos is taken into account. An improved
experimental upper bound on \sin\theta_{13} and (or) an account of quantum
kinetic effects could completely rule out this option in the future. Therefore,
\delta-leptogenesis can be also regarded as a motivation for models with
degenerate heavy neutrino spectrum.


title: Constraints on nuclear matter properties from QCD susceptibilities

abstract:
  We establish the interrelation between the QCD scalar response of the nuclear
medium and its response to a scalar probe coupled to nucleons, such as the
scalar meson responsible for the nuclear binding. The relation that we derive
applies at the nucleonic as well as at the nuclear levels. Non trivial
consequences follow. In particular it opens the possibility of relating medium
effects in the scalar meson exchange or three-body forces of nuclear physics to
QCD lattice studies of the nucleon mass


title: Parabose algebra as generalized conformal supersymmetry

abstract:
  The form of realistic space-time supersymmetry is fixed, by
Haag-Lopuszanski-Sohnius theorem, either to the familiar form of Poincare
supersymmetry or, in massless case, to that of conformal supersymmetry. We
question necessity for such strict restriction in the context of theories with
broken symmetries. In particular, we consider parabose N=4 algebra as an
extension of conformal supersymmetry in four dimensions (coinciding with the,
so called, generalized conformal supersymmetry). We show that sacrificing of
manifest Lorentz covariance leads to interpretation of the generalized
conformal supersymmetry as symmetry that contains, on equal footing, two
"rotation" groups. It is possible to reduce this large symmetry down to
observable one by simply breaking one of these two SU(2) isomorphic groups down
to its U(1) subgroup.


title:
Relation between Light Cone Distribution Amplitudes and Shape Function
  in B mesons

abstract:
  The Bakamjian-Thomas relativistic quark model provides a Poincar\'e
representation of bound states with a fixed number of constituents and, in the
heavy quark limit, form factors of currents satisfy covariance and Isgur-Wise
scaling. We compute the Light Cone Distribution Amplitudes of $B$ mesons
$\phi_{\pm}^B(\omega)$ as well as the Shape Function $S(\omega)$, that enters
in the decay $B \to X_s \gamma$, that are also covariant in this class of
models. The LCDA and the SF are related through the quark model wave function.
The former satisfy, in the limit of vanishing constituent light quark mass, the
integral relation given by QCD in the valence sector of Fock space. Using a
gaussian wave function, the obtained $S(\omega)$ is identical to the so-called
Roman Shape Function. From the parameters for the latter that fit the $B \to
X_s\gamma$ spectrum we predict the behaviour of $\phi_{\pm}^B(\omega)$. We
discuss the important role played by the constituent light quark mass. In
particular, although $\phi_-^B(0) \not= 0$ for vanishing light quark mass, a
non-vanishing mass implies the unfamiliar result $\phi_-^B (0) = 0$. Moreover,
we incorporate the short distance behaviour of QCD to $\phi_+^B (\omega)$,
which has sizeable effects at large $\omega$. We obtain the values for the
parameters $\bar{\Lambda} \cong 0.35$ GeV and $\lambda_B^{-1} \cong 1.43$
GeV$^{-1}$. We compare with other theoretical approaches and illustrate the
great variety of models found in the literature for the functions $\phi_{\pm}^B
(\omega)$; hence the necessity of imposing further constraints as in the
present paper. We briefly review also the different phenomena that are
sensitive to the LCDA.


title: Finding Efficient Recursions for Risk Aggregation by Computer Algebra

abstract:
  We derive recursions for the probability distribution of random sums by
computer algebra. Unlike the well-known Panjer-type recursions, they are of
finite order and thus allow for computation in linear time. This efficiency is
bought by the assumption that the probability generating function of the claim
size be algebraic. The probability generating function of the claim number is
supposed to be from the rather general class of D-finite functions.


title: Collapse of antiferromagnetism in CeRh2Si2 : volume versus entropy

abstract:
  The thermal expansion of the heavy fermion compound CeRh2Si2 has been
measured under pressure as a function of temperature using strain gages. A
large anomaly associated to the Neel temperature has been detected even above
the suspected critical pressure Pc = 1.05 GPa where no indication of
antiferromagnetism has been observed in calorimetry experiments sensitive to
the entropy change. An unexpected feature is the pressure slowdown of the
antiferromagnetic-paramagnetic transition by comparison to the fast pressure
collapse predicted for homogeneous first order quantum phase transition with
one unique pressure singularity at Pc. A large pressure dependance is observed
in the anisotropy of the thermal expansion measured parallel or perpendicular
to the c axis of this tetragonal crystal. The Fermi surface reconstruction
associated to the first order transition produces quite different pressure
response in the transport scattering measured along different crystallographic
directions. A brief discussion is made on other examples of first order quantum
transitions in strongly correlated electronic systems : MnSi and CeCoIn5.


title: Optimal Design of Ad Hoc Injection Networks by Using Genetic Algorithms

abstract:
  This work aims at optimizing injection networks, which consist in adding a
set of long-range links (called bypass links) in mobile multi-hop ad hoc
networks so as to improve connectivity and overcome network partitioning. To
this end, we rely on small-world network properties, that comprise a high
clustering coefficient and a low characteristic path length. We investigate the
use of two genetic algorithms (generational and steady-state) to optimize three
instances of this topology control problem and present results that show
initial evidence of their capacity to solve it.


title:
Conceptual Problems in Scattering from Localized non-Hermitian
  Potentials

abstract:
  We highlight the conceptual issues that arise when one applies the
quasi-Hermitian framework to analyze scattering from localized non-Hermitian
potentials, in particular complex square-wells or delta-functions. When treated
in the framework of conventional quantum mechanics, these potentials are
generally considered as effective theories, in which probability is not
conserved because of processes that have been ignored. However, if they are
treated as fundamental theories, the Hilbert-space metric must be changed. In
order for the newly-defined probability to be conserved, it must differ from
the standard one, even at asymptotically large distances from the scattering
centre, and the mechanism for this is the non-locality of the new metric, as we
show in detail in the model of a single complex delta function. However,
properties of distant bound-state systems, which do not interact physically
with the non-Hermitian scattering potential, should not be affected. We analyze
a model Hamiltonian that supports this contention.


title: A SUSY A4 model for fermion masses and mixings

abstract:
  We study a supersymmetric extension of the Standard Model based on discrete
A4xZ3xZ4 flavor symmetry. We obtain quark mixing angles as well as a realistic
fermion mass spectrum and we predict tribimaximal leptonic mixing by a
spontaneous breaking of A4. The top quark Yukawa interaction is present at the
renormalizable level in the superpotential while all the other Yukawa
interactions arise only at higher orders. We study the Higgs potential and show
that it can potentially solve the so called vacuum alignment problem. The
leading order predictions are not spoiled by subleading corrections.


title:
Dynamical quasiparticles properties and effective interactions in the
  sQGP

abstract:
  Dynamical quasiparticle properties are determined from lattice
  QCD along the line of the Peshier model for the running strong coupling
constant in case of three light flavors. By separating time-like and space-like
quantities in the number density and energy density the effective degrees of
freedom in the gluon and quark sector may be specified from the time-like
densities. The space-like parts of the energy densities are identified with
interaction energy (or potential energy) densities. By using the time-like
parton densities (or scalar densities) as independent degrees of freedom
variations of the potential energy densities with respect to the time-like
gluon and/or fermion densities lead to effective mean-fields for time-like
gluons and quarks as well as to effective gluon-gluon, quark-gluon and
quark-quark (quark-antiquark) interactions. The latter dynamical quantities are
found to be approximately independent on the quark chemical potential and thus
well suited for an inplementation in off-shell parton transport approaches.
Results from the dynamical quasiparticle model (DQPM) in case of two dynamical
light quark flavors are compared to lattice QCD calculations for the net quark
density as well as for the 'back-to-back' differential dilepton production rate
by $q-{\bar q}$ annihilation. The DQPM is found to pass the independent tests.


title:
On the location of the surface-attached globule phase in collapsing
  polymers

abstract:
  We investigate the existence and location of the surface phase known as the
"Surface-Attached Globule" (SAG) conjectured previously to exist in lattice
models of three-dimensional polymers when they are attached to a wall that has
a short range potential. The bulk phase, where the attractive intra-polymer
interactions are strong enough to cause a collapse of the polymer into a
liquid-like globule and the wall either has weak attractive or repulsive
interactions, is usually denoted Desorbed-Collapsed or DC. Recently this DC
phase was conjectured to harbour two surface phases separated by a boundary
where the bulk free energy is analytic while the surface free energy is
singular. The surface phase for more attractive values of the wall interaction
is the SAG phase. We discuss more fully the properties of this proposed surface
phase and provide Monte Carlo evidence for self-avoiding walks up to length 256
that this surface phase most likely does exist. Importantly, we discuss
alternatives for the surface phase boundary. In particular, we conclude that
this boundary may lie along the zero wall interaction line and the bulk phase
boundaries rather than any new phase boundary curve.


title: Dyon Death Eaters

abstract:
  We study general two-body decays of primitive and non-primitive 1/4-BPS dyons
in four-dimensional type IIB string compactifications. We find a ``master
equation'' for marginal stability that generalises the curve found by Sen for
half-BPS decay, and analyse this equation in a variety of cases including
decays to 1/4-BPS products. For half-BPS decays, an interesting and useful
relation is exhibited between walls of marginal stability and the mathematics
of Farey sequences and Ford circles. We exhibit an example in which two curves
of marginal stability intersect in the interior of moduli space.


title:
On the semi-dynamical reflection equation: solutions and structure
  matrices

abstract:
  Explicit solutions of the non-constant semi-dynamical reflection equation are
constructed, together with suitable parametrizations of their structure
matrices. Considering the semi-dynamical reflection equation with rational
non-constant Arutyunov-Chekhov-Frolov structure matrices, and a specific
meromorphic ansatz, it is found that only two sets of the previously found
constant solutions are extendible to the non-constant case. In order to
simplify future constructions of spin-chain Hamiltonians, a parametrization
procedure is applied explicitly to all elements of the semi-dynamical
reflection equation available. Interesting expressions for `twists' and
R-matrices entering the parametrization procedure are found. In particular,
some expressions for the R-matrices seem to appear here for the first time. In
addition, a new set of consistent structure matrices for the semi-dynamical
reflection equation is obtained.


title: The optical counterpart of IGR J00291+5934 in quiescence

abstract:
  The recent (December 2004) discovery of the sixth accretion-powered
millisecond X-ray pulsar IGR J00291+5934 provides a very good chance to deepen
our knowledge of such systems. Although these systems are well studied at high
energies, poor informations are available for their optical/NIR counterparts
during quiescence. Up to now, only for SAX J1808.4-3658, the first discovered
system of this type, we have a secure multiband detection of its optical
counterpart in quiescence. Among the seven known system IGR J00291+5934 is the
one that resembles SAX J1808.4-3658 more closely. With the Italian 3.6 m TNG
telescope, we have performed deep optical and NIR photometry of the field of
IGR J00291+5934 during quiescence in order to look for the presence of a
variable counterpart. We present here the first multiband ($VRIJH$) detection
of the optical and NIR counterpart of IGR J00291+5934 in quiescence as well as
a deep upper limit in the $K-$band. We obtain an optical light curve that shows
variability consistent with a sinusoidal modulation at the known 2.46 hr
orbital period and present evidence for a strongly irradiated companion.


title: Cooperative effects in molecular conduction

abstract:
  Current experimental and theoretical studies on the effect of intermolecular
interactions on molecular conduction appear to be in conflict with each other.
In particular, some experimental results, e.g., the observation of
2-dimensional free-particle character for interface bound electrons indicate
strong intermolecular interactions while other observations indicate an
additive character of conduction properties. In this paper we use a generic
tight binding model with a physically motivated choice of parameters in order
to examine this issue. The model encompasses direct intermolecular interactions
as well as through-metal interactions and can be solved exactly to yield
spectral properties (surface density of states) and transport characteristics
(transmission coefficients and current-voltage behaviors) for single molecule
junctions, molecular islands and molecular layers. We find linear scaling of
conduction properties with the number of conducting molecules in junctions
characterized by molecular layers when the probe (STM tip) addresses different
numbers of molecules; however, the conduction per molecule can differ
significantly from that of an isolated single molecule. When a junction
involves finite molecular islands of varying sizes, linear scaling sets in only
beyond a certain molecular island size, of the order of a few tens of
molecules. Implications for current observation of linear scaling behaviors are
discussed.


title: PT-symmetric waveguides

abstract:
  We introduce a planar waveguide of constant width with non-Hermitian
PT-symmetric Robin boundary conditions. We study the spectrum of this system in
the regime when the boundary coupling function is a compactly supported
perturbation of a homogeneous coupling. We prove that the essential spectrum is
positive and independent of such perturbation, and that the residual spectrum
is empty. Assuming that the perturbation is small in the supremum norm, we show
that it gives rise to real weakly-coupled eigenvalues converging to the
threshold of the essential spectrum. We derive sufficient conditions for these
eigenvalues to exist or to be absent. Moreover, we construct the leading terms
of the asymptotic expansions of these eigenvalues and the associated
eigenfunctions.


title: The coding complexity of L\'evy processes

abstract:
  We investigate the high resolution coding problem for general real-valued
L\'evy processes under L^p[0,1]-norm distortion. Tight asymptotic formulas are
found under mild regularity assumptions.


title: Many-body wave scattering by small bodies and applications

abstract:
  A rigorous reduction of the many-body wave scattering problem to solving a
linear algebraic system is given bypassing solving the usual system of integral
equation. The limiting case of infinitely many small particles embedded into a
medium is considered and the limiting equation for the field in the medium is
derived. The impedance boundary conditions are imposed on the boundaries of
small bodies. The case of Neumann boundary conditions (acoustically hard
particles) is also considered. Applications to creating materials with a
desired refraction coefficient are given. It is proved that by embedding
suitable number of small particles per unit volume of the original material
with suitable boundary impedances one can create a new material with any
desired refraction coefficient. The governing equation is a scalar Helmholtz
equation, which one obtains by Fourier transforming the wave equation.


title:
Modifications of the analytical properties of the two-point correlation
  function in Drell-Yan scattering, caused by rescattering-induced
  decorrelation of the initial hadron state

abstract:
  In a recent work, factorization breaking interactions and T-odd distributions
have been analyzed from the point of view of statistical mechanics. One of the
central points was the process leading from the coherent initial hadron state
to an incoherent set of short-range parton states, in presence of factorization
breaking interactions. This time evolution was named ``partonization'', or also
``de-correlation'', to distinguish it from an ordinary hadron-quark-spectator
splitting vertex. Here an example is shown for a correlation amplitude
describing an extreme case for such a process, where the initial state phases
are lost, but the probability distributions are perfectly conserved. This
requires introducing degrees of freedom that are not normally considered in a
factorized scheme, and that must disappear at some stage of the calculations
for the factorization scheme to survive. The explicit time-evolution character
of the decorrelation process disappears when these degrees of freedom are
integrated, but the integrated correlator presents modified analytical
properties as a consequence. for the factorization scheme to survive. The
explicit time-evolution character of the de-correlation process disappears when
these degrees of freedom are integrated, but the integrated correlator presents
nontrivial analytic properties as a consequence. At certain conditions,
factorization is preserved, at the price of introducing T-odd contributions.


title: p-Adic Modelling of the Genome and the Genetic Code

abstract:
  The present paper is devoted to foundations of p-adic modelling in genomics.
Considering nucleotides, codons, DNA and RNA sequences, amino acids, and
proteins as information systems, we have formulated the corresponding p-adic
formalisms for their investigations. Each of these systems has its
characteristic prime number used for construction of the related information
space. Relevance of this approach is illustrated by some examples. In
particular, it is shown that degeneration of the genetic code is a p-adic
phenomenon. We have also put forward a hypothesis on evolution of the genetic
code assuming that primitive code was based on single nucleotides and
chronologically first four amino acids. This formalism of p-adic genomic
information systems can be implemented in computer programs and applied to
various concrete cases.


title:
PHOTOS Monte Carlo for precision simulation of QED in decays - History
  and properties of the project

abstract:
  Because of properties of QED, the bremsstrahlung corrections to decays of
particles or resonances can be calculated, with a good precision, separately
from other effects. Thanks to the widespread use of event records such
calculations can be embodied into a separate module of Monte Carlo simulation
chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo
program is used for this purpose since nearly 20 years now. In the following
talk let us review the main ideas and constraints which shaped the program
version of today and enabled it widespread use. We will concentrate specially
on conflicting requirements originating from the properties of QED matrix
elements on one side and degrading (evolving) with time standards of event
record(s). These issues, quite common in other modular software applications,
become more and more difficult to handle as precision requirements become
higher.


title:
Time-dependent density functional study of the electronic spectra of
  oligoacenes in the charge states -1, 0, +1, and +2

abstract:
  We present a systematic theoretical study of the five smallest oligoacenes
(naphthalene, anthracene, tetracene, pentacene, and hexacene) in their
anionic,neutral, cationic, and dicationic charge states. We used density
functional theory (DFT) to obtain the ground-state optimised geometries, and
time-dependent DFT (TD-DFT) to evaluate the electronic absorption spectra.
Total-energy differences enabled us to evaluate the electron affinities and
first and second ionisation energies, the quasiparticle correction to the
HOMO-LUMO energy gap and an estimate of the excitonic effects in the neutral
molecules. Electronic absorption spectra have been computed by combining two
different implementations of TD-DFT: the frequency-space method to study
general trends as a function of charge-state and molecular size for the
lowest-lying in-plane long-polarised and short-polarised $\pi\to\pi^\star$
electronic transitions, and the real-time propagation scheme to obtain the
whole photo-absorption cross-section up to the far-UV. Doubly-ionised PAHs are
found to display strong electronic transitions of $\pi\to\pi^\star$ character
in the near-IR, visible, and near-UV spectral ranges, like their singly-charged
counterparts. While, as expected, the broad plasmon-like structure with its
maximum at about 17-18 eV is relatively insensitive to the charge-state of the
molecule, a systematic decrease with increasing positive charge of the
absorption cross-section between about 6 and about 12 eV is observed for each
member of the class.


title:
Block-Toeplitz determinants, chess tableaux, and the type $\hat{A_1}$
  Geiss-Leclerc-Schroer $\phi$-map

abstract:
  We evaluate the Geiss-Leclerc-Schroer $\phi$-map for shape modules over the
preprojective algebra $\Lambda$ of type $\hat{A_1}$ in terms of matrix minors
arising from the block-Toeplitz representation of the loop group
$\SL_2(\mathcal{L})$. Conjecturally these minors are among the cluster
variables for coordinate rings of unipotent cells within $\SL_2(\mathcal{L})$.
In so doing we compute the Euler characteristic of any generalized flag variety
attached to a shape module by counting standard tableaux of requisite shape and
parity; alternatively by counting chess tableaux of requisite shape and
content.


title: Arrival Time Statistics in Global Disease Spread

abstract:
  Metapopulation models describing cities with different populations coupled by
the travel of individuals are of great importance in the understanding of
disease spread on a large scale. An important example is the Rvachev-Longini
model [{\it Math. Biosci.} {\bf 75}, 3-22 (1985)] which is widely used in
computational epidemiology. Few analytical results are however available and in
particular little is known about paths followed by epidemics and disease
arrival times. We study the arrival time of a disease in a city as a function
of the starting seed of the epidemics. We propose an analytical Ansatz, test it
in the case of a spreading on the world wide air transportation network, and
show that it predicts accurately the arrival order of a disease in world-wide
cities.


title:
Fine structure of the local pseudogap and Fano effect for
  superconducting electrons near a zigzag graphene edge

abstract:
  Motivated by recent scanning tunneling experiments on zigzag-terminated
graphene this paper investigates an interplay of evanescent and extended
quasiparticle states in the local density of states (LDOS) near a zigzag edge
using the Green's function of the Dirac equation. A model system is considered
where the local electronic structure near the edge influences transport of both
normal and superconducting electrons via a Fano resonance. In particular, the
temperature enhancement of the critical Josephson current and 0-pi transitions
are predicted.


title: Could a Gamma Line Betray the Mass of Light Dark Matter?

abstract:
  We compute the pair annihilation cross section of light dark matter scalar
particles into two photons, and discuss the detectability of the monochromatic
line associated with these annihilations.


title:
Decays, contact P-wave interactions and hyperfine structure in Omega-
  exotic atoms

abstract:
  Contact $P$-wave interactions connected to the Larmor interaction of a
magnetic dipole and Thomas spin precession in the filed of an electric
quadrupole are described and their implications for spectroscopy of exotic
$\Omega^{-}$-atoms are studied. In order to evaluate the magnitude of the
contact $P$-wave interactions as compared to the conventional long-range
interactions and the sensitivity of spectroscopic data to the
$\Omega^{-}$-hyperon quadrupole moment, we consider $2P$ states of $\Omega
^{-}$ atoms formed with light stable nuclei with spins $I \geq 1/2$ and atomic
numbers $Z \leq 10$. The energy level splitting caused by the contact
interactions is 2-5 orders of magnitude smaller than the conventional
long-range interactions. Strong decay widths of $p\Omega ^{-}$ atoms due to
reactions $p\Omega^{-} \to \Lambda \Xi^{0}$ and $p\Omega^{-} \to \Sigma \Xi$,
induced by $t$-channel kaon exchanges, are calculated. $\Omega ^{-}$ atoms
formed with the light nuclei have strong widths 5-6 orders of magnitude higher
than splitting caused by the contact interactions. The low-$L$ pattern in the
energy spectra of intermediate- and high-$Z$ $\Omega ^{-}$ atoms thus cannot be
observed. The $\Omega ^{-}$ quadrupole moment can be measured by observing
$X$-rays from circular transitions between high-$L$ levels in $\Omega^{-}$
exotic atoms. The effect of strong interactions in $^{208}$Pb$\Omega ^{-}$
atoms is negligible starting from $L \sim 10$. The contact $P$-wave
interactions exist in ordinary atoms and $\mu$-meson atoms.

categories: nucl-th hep-ex hep-ph nucl-ex physics.atom-ph


title: An sl(2) tangle homology and seamed cobordisms

abstract:
  We construct a bigraded (co)homology theory which depends on a parameter a,
and whose graded Euler characteristic is the quantum sl(2) link invariant. We
follow Bar-Natan's approach to tangles on one side, and Khovanov's sl(3) theory
for foams on the other side. Our theory is properly functorial under tangle
cobordisms, and a version of the Khovanov sl(2) invariant (or Lee's
modification of it) corresponds to a=0 (or a=1). In particular, our
construction naturally resolves the sign ambiguity in the functoriality of
Khovanov's sl(2) homology theory.


title: Extremal Problems in Minkowski Space related to Minimal Networks

abstract:
  We solve the following problem of Z. F\"uredi, J. C. Lagarias and F. Morgan
[FLM]: Is there an upper bound polynomial in $n$ for the largest cardinality of
a set S of unit vectors in an n-dimensional Minkowski space (or Banach space)
such that the sum of any subset has norm less than 1? We prove that |S|\leq 2n
and that equality holds iff the space is linearly isometric to \ell^n_\infty,
the space with an n-cube as unit ball. We also remark on similar questions
raised in [FLM] that arose out of the study of singularities in
length-minimizing networks in Minkowski spaces.


title: On universal C^*-algebras generated by n projections with scalar sum

abstract:
  We study the universal C^*-algebras generated by n projections $p_1, >...,
p_n$ subject to the relation $p_1+... p_n = \lambda 1$, $\lambda \in \mathbb
R$. The questions of when these C^*-algebras are type I, nuclear or exact are
considered. It is proved also that among these algebras there is continuum of
mutually nonisomorphic ones.


title: Adiabatic quantum search with atoms in a cavity driven by lasers

abstract:
  We propose an implementation of the quantum search algorithm of a marked item
in an unsorted list of N items by adiabatic passage in a cavity-laser-atom
system. We use an ensemble of N identical three-level atoms trapped in a
single-mode cavity and driven by two lasers. In each atom, the same level
represents a database entry. One of the atoms is marked by having an energy gap
between its two ground states. Appropriate time delays between the two laser
pulses allow one to populate the marked state starting from an initial
entangled state within a decoherence-free adiabatic subspace. The time to
achieve such a process is shown to exhibit the Grover speedup.


title:
The four-loop DRED gauge beta-function and fermion mass anomalous
  dimension for general gauge groups

abstract:
  We present four-loop results for the gauge beta-function and the fermion mass
anomalous dimension for a gauge theory with a general gauge group and a
multiplet of fermions transforming according to an arbitrary representation,
calculated using the dimensional reduction scheme. In the special case of a
supersymmetric theory we confirm previous calculations of both the gauge
beta-function and the gaugino mass beta-function.


title: Positively curved homogeneous metrics on spheres

abstract:
  We examine homogeneous metrics on spheres and determine which ones have
positive sectional curvature. The answer is subtle and surprisingly difficult
to prove. In some cases we also determine their pinching constants. This
completes the classification of all homogeneous metrics with positive curvature
(apart from one special Aloff Wallach space where the set of homogeneous
metrics is too large).


title: Star formation histories of resolved galaxies

abstract:
  The impact of HST photometry and European astronomy in studies concerning the
star formation histories of resolved galaxies is described. Our current
knowledge of the star formation history of systems within 10-20 Mpc, as derived
from the colour-magnitude diagrams of their resolved stellar populations, is
reviewed, as well as the impact of these results on our understanding of galaxy
evolution.


title: Measurement of |V_us| using hadronic tau decays from BaBar & Belle

abstract:
  We report on measurements of branching fractions for several hadronic tau
decays to final states with kaons, which can be used to determine the strange
quark mass and the element |V_us| of the Cabibbo-Kobayashi-Maskawa quark-mixing
matrix. The results are obtained from data collected with the BaBar and Belle
detectors at the PEP-II and KEKB asymmetric-energy e+e- colliders at SLAC and
KEK, respectively, both operating at center-of-mass energies near the Y(4S)
resonance.


title:
Quasifree Lambda, Sigma^0, and Sigma^- electroproduction from 1,2H,
  3,4He, and carbon

abstract:
  Kaon electroproduction from light nuclei and hydrogen, using 1H, 2H, 3He,
4He, and Carbon targets has been measured at Jefferson Laboratory. The
quasifree angular distributions of Lambda and Sigma hyperons were determined at
Q^2= 0.35(GeV/c)^2 and W= 1.91GeV. Electroproduction on hydrogen was measured
at the same kinematics for reference.


title: Dalitz plot analysis of the D+ -> K- pi+ pi+ decay

abstract:
  We present a Dalitz plot analysis of the decay D+ -> K- pi+ pi+ based on 281
pb-1 of e+e- collision data produced at the psi(3770) by CESR and observed with
the CLEO-c detector. We select 67086 candidate events with a small, ~1.1%,
background for this analysis. When using a simple isobar model our results are
consistent with the previous measurements done by E791. Since our sample is
considerably larger we can explore alternative models. We find better agreement
with data when we include an isospin-two pi+pi+ S-wave contribution. We apply a
quasi model-independent partial wave analysis and measure the amplitude and
phase of the K pi and pi+pi+ S waves in the range of invariant masses from the
threshold to the maximum in this decay.


title: Resonant excitonic emission of a single quantum dot in the Rabi regime

abstract:
  We report on coherent resonant emission of the fundamental exciton state in a
single semiconductor GaAs quantum dot. Resonant regime with picoseconde laser
excitation is realized by embedding the quantum dots in a waveguiding
structure. As the pulse intensity is increased, Rabi oscillation is observed up
to three periods. The Rabi regime is achieved owing to an enhanced light-matter
coupling in the waveguide. This is due to a \emph{slow light effect}
($c/v_{g}\simeq 3000$), occuring when an intense resonant pulse propagates in a
medium. The resonant control of the quantum dot fundamental transition opens
new possibilities in quantum state manipulation and quantum optics experiments
in condensed matter physics.


title:
On primes in arithmetic progression having a prescribed primitive root.
  II

abstract:
  Let a and f be coprime positive integers. Let g be an integer. Under the
Generalized Riemann Hypothesis (GRH) it follows by a result of H.W. Lenstra
that the set of primes p such that p=a(mod f) and g is a primitive root modulo
p has a natural density. In this note this density is explicitly evaluated with
an Euler product as result.


title: Cones over pseudo-Riemannian manifolds and their holonomy

abstract:
  By a classical theorem of Gallot (1979), a Riemannian cone over a complete
Riemannian manifold is either flat or has irreducible holonomy. We consider
metric cones with reducible holonomy over pseudo-Riemannian manifolds. First we
describe the local structure of the base of the cone when the holonomy of the
cone is decomposable. For instance, we find that the holonomy algebra of the
base is always the full pseudo-orthogonal Lie algebra. One of the global
results is that a cone over a compact and complete pseudo-Riemannian manifold
is either flat or has indecomposable holonomy. Then we analyse the case when
the cone has indecomposable but reducible holonomy, which means that it admits
a parallel isotropic distribution. This analysis is carried out, first in the
case where the cone admits two complementary distributions and, second for
Lorentzian cones. We show that the first case occurs precisely when the local
geometry of the base manifold is para-Sasakian and that of the cone is
para-K\"ahlerian. For Lorentzian cones we get a complete description of the
possible (local) holonomy algebras in terms of the metric of the base manifold.


title: Water vapour in the atmosphere of a transiting extrasolar planet

abstract:
  Water is predicted to be among, if not the most abundant molecular species
after hydrogen in the atmospheres of close-in extrasolar giant planets
(hot-Jupiters) Several attempts have been made to detect water on an exoplanet,
but have failed to find compelling evidence for it or led to claims that should
be taken with caution. Here we report an analysis of recent observations of the
hot-Jupiter HD189733b taken during the transit, where the planet passed in
front of its parent star. We find that absorption by water vapour is the most
likely cause of the wavelength-dependent variations in the effective radius of
the planet at the infrared wavelengths 3.6, 5.8 and 8 microns. The larger
effective radius observed at visible wavelengths may be due to either star
variability or the presence of clouds/hazes. We explain the most recent thermal
infrared observations of the planet during secondary transit behind the star,
reporting a non-detection of water on HD189733b, as being a consequence of the
nearly isothermal vertical profile of the planet.s atmosphere. Our results show
that water is detectable on extrasolar planets using the primary transit
technique and that the infrared should be a better wavelength region than the
visible, for such searches.


title: Exact vortex nucleation and cooperative vortex tunneling in dilute BECs

abstract:
  With the imminent advent of mesoscopic rotating BECs in the lowest Landau
level (LLL) regime, we explore LLL vortex nucleation. An exact many-body
analysis is presented in a weakly elliptical trap for up to 400 particles.
Striking non-mean field features are exposed at filling factors >>1 . Eg near
the critical rotation frequency pairs of energy levels approach each other with
exponential accuracy. A physical interpretation is provided by requantising a
mean field theory, where 1/N plays the role of Planck's constant, revealing two
vortices cooperatively tunneling between classically degenerate energy minima.
The tunnel splitting variation is described in terms of frequency, particle
number and ellipticity.


title:
Full solution for the storage of correlated memories in an
  autoassociative memory

abstract:
  We complement our previous work [arxiv: 0707.0565] with the full (non
diluted) solution describing the stable states of an attractor network that
stores correlated patterns of activity. The new solution provides a good fit of
simulations of a network storing the feature norms of McRae and colleagues
[McRae et al, 2005], experimentally obtained combinations of features
representing concepts in semantic memory. We discuss three ways to improve the
storage capacity of the network: adding uninformative neurons, removing
informative neurons and introducing popularity-modulated hebbian learning. We
show that if the strength of synapses is modulated by an exponential decay of
the popularity of the pre-synaptic neuron, any distribution of patterns can be
stored and retrieved with approximately an optimal storage capacity - i.e, C ~
I.p, the minimum number of connections per neuron needed to sustain the
retrieval of a pattern is proportional to the information content of the
pattern multiplied by the number of patterns stored in the network.


title:
Solution of the Multicomponent Boltzmann Equation Based on an Extended
  Set of Observables

abstract:
  We present the perturbative solution of the multicomponent Boltzmann kinetic
equation based on the set of observables including the hydrodynamic velocity
and temperature for each component. The solution is obtained by modifying the
formal density scaling scheme by Enskog, such that the density of each
component is scaled independently. As a result we obtain the species momentum
and energy balance equations with the source terms describing the transfer of
corresponding quantities between different components. In the zero order
approximation those are the Euler equations with the momentum and heat
diffusion included in the form of the classical Maxwell-Stefan diffusion terms.
The first order approximation results in equations of a Navier-Stokes type with
the partial viscosity and heat conductivity including only the correlations of
the particles of the same component. The first order corrections to the
Maxwell-Stefan terms as well as the contributions bilinear in gradients and
differences of observables are calculated. The first order momentum source term
is shown to include thermal diffusion. The nondiagonal (in component indexes)
components of viscosity and heat conductivity appear as second order
contributions.


title: Experimental Validation of Quantum Game Theory

abstract:
  This article uses data from two experimental studies of two-person Prisoner's
Dilemma games [1, 2] and compares the data with the theoretic predictions
calculated with the use of a quantum game theoretical method. The experimental
findings of the cooperation percentage Cp indicate a strong connectivity with
the properties of a novel function (N), which depends on the payoff parameters
of the game and the entanglement parameter . A classification scheme depending
on four quantum cooperation indicators is developed to describe cooperation in
real two-person games. The quantum indicators lead to results, that are at
least as good as the cooperation predictions derived from classical game
theory.


title: A formally exact field theory for classical systems at equilibrium

abstract:
  We propose a formally exact statistical field theory for describing classical
fluids with ingredients similar to those introduced in quantum field theory. We
consider the following essential and related problems : i) how to find the
correct field functional (Hamiltonian) which determines the partition function,
ii) how to introduce in a field theory the equivalent of the indiscernibility
of particles, iii) how to test the validity of this approach. We can use a
simple Hamiltonian in which a local functional transposes, in terms of fields,
the equivalent of the indiscernibility of particles. The diagrammatic expansion
and the renormalization of this term is presented. This corresponds to a non
standard problem in Feynman expansion and requires a careful investigation.
Then a non-local term associated with an interaction pair potential is
introduced in the Hamiltonian. It has been shown that there exists a mapping
between this approach and the standard statistical mechanics given in terms of
Mayer function expansion. We show on three properties (the chemical potential,
the so-called contact theorem and the interfacial properties) that in the field
theory the correlations are shifted on non usual quantities. Some perspectives
of the theory are given.


title:
Quantum Gravity from Simplices: Analytical Investigations of Causal
  Dynamical Triangulations

abstract:
  A potentially powerful approach to quantum gravity has been developed over
the last few years under the name of Causal Dynamical Triangulations. Numerical
simulations have given very interesting results in the cases of two, three and
four spacetime dimension. The aim of this thesis is to give an introduction to
the subject (Chapter 1), and try to push the analytical understanding of these
models further. This is done by first studying (Chapter 2) the case of a
(1+1)-dimensional spacetime coupled to matter, in the form of an Ising model,
by means of high- and low-temperature expansions. And after (Chapter 3) by
studying a specific model in (2+1) dimensions, whose solution and continuum
limit are presented.


title: Tracking and vertexing at ATLAS

abstract:
  Several algorithms for tracking and for primary and secondary vertex
reconstruction have been developed by the ATLAS collaboration following
different approaches. This has allowed a thorough cross-check of the
performances of the algorithms and of the reconstruction software. The results
of the most recent studies on this topic are discussed and compared.


title: Evidence for contact delocalization in atomic scale friction

abstract:
  We analyze an advanced two-spring model with an ultra-low effective tip mass
to predict nontrivial and physically rich 'fine structure' in the atomic
stick-slip motion in Friction Force Microscopy (FFM) experiments. We
demonstrate that this fine structure is present in recent, puzzling
experiments. This shows that the tip apex can be completely or partially
delocalized, thus shedding new light on what is measured in FFM and, possibly,
what can happen with the asperities that establish the contact between
macroscopic sliding bodies.


title: About Bianchi I with time varying constants

abstract:
  In this paper we study how to attack through different techniques a perfect
fluid Bianchi I model with variable G, and $\Lambda.$ These tactics are: Lie
groups method (LM), imposing a particular symmetry, self-similarity (SS),
matter collineations (MC). and kinematical self-similarity (KSS). We compare
both tactics since they are quite similar (symmetry principles). We arrive to
the conclusion that the LM is too restrictive and brings us to get only the
flat FRW solution with G=const. and $\Lambda=0$. The SS, MC and KSS approaches
bring us to obtain the following solution: G is a decreasing time function and
$\Lambda\thickapprox t^{-2}$, with $\Lambda<0$, while the exponents of the
scale factor must satisfy the conditions $\sum_{i=1}% ^{3}\alpha_{i}=1$ and
$\sum_{i=1}^{3}\alpha_{i}^{2}<1,$ $\forall\omega \in(-1,1)$, relaxing in this
way the Kasner conditions.


title:
The fluctuations, under time reversal, of the natural time and the
  entropy distinguish similar looking electric signals of different dynamics

abstract:
  We show that the scale dependence of the fluctuations of the natural time
itself under time reversal provides a useful tool for the discrimination of
seismic electric signals (critical dynamics) from noises emitted from man made
sources as well as for the determination of the scaling exponent. We present
recent data of electric signals detected at the Earth's surface, which confirm
that the value of the entropy in natural time as well as its value under time
reversal are smaller than that of the entropy of a "uniform" distribution.


title:
Metric Operators for Quasi-Hermitian Hamiltonians and Symmetries of
  Equivalent Hermitian Hamiltonians

abstract:
  We give a simple proof of the fact that every diagonalizable operator that
has a real spectrum is quasi-Hermitian and show how the metric operators
associated with a quasi-Hermitian Hamiltonian are related to the symmetry
generators of an equivalent Hermitian Hamiltonian.


title:
Temperature dependence of the angle resolved photoemission spectra in
  the undoped cuprates: self-consistent approach to the t-J-Holstein model

abstract:
  We develop a novel self-consistent approach for studying the angle resolved
photoemission spectra (ARPES) of a hole in the t-J-Holstein model giving
perfect agreement with numerically exact Diagrammatic Monte Carlo data at zero
temperature for all regimes of electron-phonon coupling. Generalizing the
approach to finite temperatures we find that the anomalous temperature
dependence of the ARPES in undoped cuprates is explained by cooperative
interplay of coupling of the hole to magnetic fluctuations and strong
electron-phonon interaction.


title:
A mechanism for unipolar resistance switching in oxide non-volatile
  memory devices

abstract:
  Building on a recently introduced model for non-volatile resistive switching,
we propose a mechanism for unipolar resistance switching in
metal-insulator-metal sandwich structures. The commutation from the high to low
resistance state and back can be achieved with successive voltage sweeps of the
same polarity. Electronic correlation effects at the metal-insulator interface
are found to play a key role to produce a resistive commutation effect in
qualitative agreement with recent experimental reports on binary transition
metal oxide based sandwich structures.


title: High resolution simulations of unstable modes in a collisionless disc

abstract:
  We present N-body simulations of unstable spiral modes in a dynamically cool
collisionless disc. We show that spiral modes grow in a thin collisionless disk
in accordance with the analytical perturbation theory. We use the particle-mesh
code SUPERBOX with nested grids to follow the evolution of unstable spirals
that emerge from an unstable equilibrium state. We use a large number of
particles (up to 40 million particles) and high-resolution spatial grids in our
simulations (128^3 cells). These allow us to trace the dynamics of the unstable
spiral modes until their wave amplitudes are saturated due to nonlinear
effects. In general, the results of our simulations are in agreement with the
analytical predictions. The growth rate and the pattern speed of the most
unstable bar-mode measured in N-body simulations agree with the linear
analysis. However the parameters of secondary unstable modes are in lesser
agreement because of the still limited resolution of our simulations.


title: Ordering effects in diluted magnetic semiconductors

abstract:
  We review recently developed two-step approach for description of electronic
and magnetic properties of a new class of materials, the diluted magnetic
semiconductors. In the first step we construct, on the basis of the
state-of-the-art first-principles electronic structure calculations, the
effective Ising and Heisenberg Hamiltonians which describe, respectively, the
alloy phase stability and the magnetic excitations in the system. In the second
step, we analyze properties of these effective Hamiltonians by various methods
of statistical physics. As a case study, the prototypical diluted magnetic
semiconductor Ga_{1-x}Mn_{x}As is studied in detail. We determine, among
others, a possibility for clustering in this system, formation energies of
various compensating defects, and estimate short-range order parameters
describing ordering tendencies in a system. On the other hand, by using
recently developed local random-phase approximation approach, we evaluate the
system Curie temperature and demonstrate its strong dependence on the sample
preparation. We also emphasize the relevance of proper inclusion of the
randomness in positions of magnetic impurities for a reliable estimate of the
system critical temperature. Finally, we compare calculated Curie temperatures
with available experimental data and briefly mention relation to other
theoretical approaches.


title: Coherent control of a single electron spin with electric fields

abstract:
  Manipulation of single spins is essential for spin-based quantum information
processing. Electrical control instead of magnetic control is particularly
appealing for this purpose, since electric fields are easy to generate locally
on-chip. We experimentally realize coherent control of a single electron spin
in a quantum dot using an oscillating electric field generated by a local gate.
The electric field induces coherent transitions (Rabi oscillations) between
spin-up and spin-down with pi/2 rotations as fast as ~55ns. Our analysis
indicates that the electrically-induced spin transitions are mediated by the
spin-orbit interaction. Taken together with the recently demonstrated coherent
exchange of two neighboring spins, our results demonstrate the feasibility of
fully electrical manipulation of spin qubits.


title: The POWHEG-hvq manual version 1.0

abstract:
  This note documents the use of the POWHEG-hvq package, a generator for heavy
flavour hadroproduction at next-to-leading order in QCD, that can be easily
interfaced to shower Monte Carlo programs, in such a way that NLO and shower
accuracy are both maintained.


title:
Bergman metrics and geodesics in the space of K\"ahler metrics on toric
  varieties

abstract:
  Geodesics on the infinite dimensional symmetric space $\hcal$ of K\"ahler
metrics in a fixed K\"ahler class on a projective K\"ahler manifold X are
solutions of a homogeneous complex Monge-Amp\`ere equation in $X \times A$,
where $A \subset \C$ is an annulus. They are analogues of 1PS (one-parameter
subgroups) on symmetric spaces $G_{\C}/G$. Donaldson, Arezzo-Tian and
Phong-Sturm raised the question whether Monge-Amp\`ere geodesics can be
approximated by 1PS geodesics in the symmetric spaces of Bergman metrics.
Phong-Sturm proved weak C^0 convergence of Bergman to Monge-Amp\`ere geodesics
on a general \kahler manifold. In this article we prove convergence in $C^2(A
\times X)$ in the case of toric K\"ahler metrics, extending our earlier result
on $\CP^1$.


title:
A numerical method of solving time-dependent Hartree-Fock-Bogoliubov
  equation with Gogny interaction

abstract:
  A numerical method to solve time-dependent Hartree-Fock-Bogoliubov equation
is proposed to treat the case with Gogny effective interaction. To check the
feasibility of the method, it is applied to oxygen isotope O20 and small
amplitude oscillations are calculated. The conservation of the nucleon numbers
as well as energy expectation value is demonstrated. The strength distributions
of the small amplitude quadrupole oscillations are also shown.


title:
Mixed Hodge complexes and L^2-cohomology for local systems on ball
  quotients

abstract:
  We study the $L^2$--cohomology of certain local systems on non-compact
arithmetic ball quotients $X=\Gamma \backslash \B_n$, in particular vanishing
and non--vanishing results. We also give generalizations to higher dimensional
ball quotients and study the mixed Hodge structure on the sheaf cohomology of a
local system with the $L^2$-cohomology contributing to the lowest weight part.


title:
Socio-economical dynamics as a solvable spin system on co-evolving
  networks

abstract:
  We consider social systems in which agents are not only characterized by
their states but also have the freedom to choose their interaction partners to
maximize their utility. We map such systems onto an Ising model in which spins
are dynamically coupled by links in a dynamical network. In this model there
are two dynamical quantities which arrange towards a minimum energy state in
the canonical framework: the spins, s_i, and the adjacency matrix elements,
c_{ij}. The model is exactly solvable because microcanonical partition
functions reduce to products of binomial factors as a direct consequence of the
c_{ij} minimizing energy. We solve the system for finite sizes and for the two
possible thermodynamic limits and discuss the phase diagrams.


title:
Hydrodynamical thermotransport relaxation times of semiconductor
  electrons via acoustic phonons

abstract:
  We propose a hydrodynamic model to study the thermotransport properties of
semiconductor electrons. From the semiclassical Boltzmann equation a set of
balance equations is built for the relevant fields. The electron density, the
electron energy density, the electric current density and the heat flux density
are considered as the basic fields of direct transport and cross effect fluxes.
The kinetic relaxation times of the production terms are calculated by
considering the electron-acoustic phonon interaction as the leading microscopic
scattering process. To justify the long time thermalization regime, the Onsager
symmetry relations are proved, both on the completely degenerate and non
degenerate limits.


title: Universal Reinforcement Learning

abstract:
  We consider an agent interacting with an unmodeled environment. At each time,
the agent makes an observation, takes an action, and incurs a cost. Its actions
can influence future observations and costs. The goal is to minimize the
long-term average cost. We propose a novel algorithm, known as the active LZ
algorithm, for optimal control based on ideas from the Lempel-Ziv scheme for
universal data compression and prediction. We establish that, under the active
LZ algorithm, if there exists an integer $K$ such that the future is
conditionally independent of the past given a window of $K$ consecutive actions
and observations, then the average cost converges to the optimum. Experimental
results involving the game of Rock-Paper-Scissors illustrate merits of the
algorithm.


title:
A Positive-Weight Next-to-Leading-Order Monte Carlo for Heavy Flavour
  Hadroproduction

abstract:
  We present a next-to-leading order calculation of heavy flavour production in
hadronic collisions that can be interfaced to shower Monte Carlo programs. The
calculation is performed in the context of the POWHEG method. It is suitable
for the computation of charm, bottom and top hadroproduction. In the case of
top production, spin correlations in the decay products are taken into account.


title: Microscopic description of nuclear quantum phase transitions

abstract:
  The relativistic mean-field framework, extended to include correlations
related to restoration of broken symmetries and to fluctuations of the
quadrupole deformation, is applied to a study of shape transitions in Nd
isotopes. It is demonstrated that the microscopic self-consistent approach,
based on global effective interactions, can describe not only general features
of transitions between spherical and deformed nuclei, but also the singular
properties of excitation spectra and transition rates at the critical point of
quantum shape phase transition.


title:
NNLO fermionic corrections to the charm quark mass dependent matrix
  elements in B -> X_s gamma

abstract:
  We compute the virtual O(alpha_s^2) fermionic contributions to the charm
quark mass dependent matrix elements of the B -> X_s gamma decay. In the case
of a massless quark loop insertion into the gluon propagator, our result
obtained as an expansion in z=m_c^2/m_b^2 and an exact expression in terms of
multi-fold MB integrals, confirms the findings of Bieri, Greub and Steinhauser
[19]. We observe, however, large deviations in the case of a b-quark loop
insertion.The charm quark loop shows smaller, but still noticeable differences.


title: Nonnegatively and Positively curved manifolds

abstract:
  This is a survey written for a special edition of the journal of differential
geometry.


title:
Isospin Distillation with Radial Flow: a Test of the Nuclear Symmetry
  Energy

abstract:
  We discuss mechanisms related to isospin transport in central collisions
between neutron-rich systems at Fermi energies. A fully consistent study of the
isospin distillation and expansion dynamics in two-component systems is
presented in the framework of a stochastic transport theory. We analyze
correlations between fragment observables, focusing on the study of the average
N/Z of fragments, as a function of their kinetic energy. We identify an
EOS-dependent relation between these observables, allowing to better
characterize the fragmentation path and to access new information on the low
density behavior of the symmetry energy.


title: Forward-jet production in deep inelastic ep scattering at HERA

abstract:
  Forward jet cross sections have been measured in neutral current deep
inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an
integrated luminosity of ${81.8 \rm pb}^{-1}$. Measurements are presented for
inclusive forward jets as well as for forward jets accompanied by a dijet
system. The explored phase space, with jet pseudorapidity up to 4.3 is expected
to be particularly sensitive to the dynamics of QCD parton evolution at low x.
The measurements are compared to fixed-order QCD calculations and to
leading-order parton-shower Monte Carlo models.


title:
Stratificational and antipodean properties of boundary states for N x N
  density matrices

abstract:
  We investigate the space of N x N dimensional density matrices. We show that
there exist strata such that boundary states \rho_{p} with p zero eigenvalues
lie on or outside the spheres with radii r_{p}=\sqrt{p/N(N-p)}. Moreover, we
show that if in a certain direction there is a boundary state with q=N-p equal
eigenvalues, then in the opposite (antipodean) direction exists a boundary
state with p=N-q equal eigenvalues.


title: Channel Capacity Estimation using Free Probability Theory

abstract:
  In many channel measurement applications, one needs to estimate some
characteristics of the channels based on a limited set of measurements. This is
mainly due to the highly time varying characteristics of the channel. In this
contribution, it will be shown how free probability can be used for channel
capacity estimation in MIMO systems. Free probability has already been applied
in various application fields such as digital communications, nuclear physics
and mathematical finance, and has been shown to be an invaluable tool for
describing the asymptotic behaviour of many large-dimensional systems. In
particular, using the concept of free deconvolution, we provide an
asymptotically (w.r.t. the number of observations) unbiased capacity estimator
for MIMO channels impaired with noise called the free probability based
estimator. Another estimator, called the Gaussian matrix mean based estimator,
is also introduced by slightly modifying the free probability based estimator.
This estimator is shown to give unbiased estimation of the moments of the
channel matrix for any number of observations. Also, the estimator has this
property when we extend to MIMO channels with phase off-set and frequency
drift, for which no estimator has been provided so far in the literature. It is
also shown that both the free probability based and the Gaussian matrix mean
based estimator are asymptotically unbiased capacity estimators as the number
of transmit antennas go to infinity, regardless of whether phase off-set and
frequency drift are present. The limitations in the two estimators are also
explained. Simulations are run to assess the performance of the estimators for
a low number of antennas and samples to confirm the usefulness of the
asymptotic results.


title: Probing Little Higgs Model in e+ e- --> nu nubar gamma Process

abstract:
  We study the process e+e- -->nu nubar gamma to search for its sensitivity to
the extra gauge bosons Z_2, Z_3 and W_2 which are suggested by the little Higgs
models. We find that the ILC with sqrt(s)=0.5 TeV and CLIC with sqrt(s)=3 TeV
cover different regions of the LHM parameters. We show that this channel can
provide accurate determination of the parameters, complementary to measurements
of the extra gauge bosons at the coming LHC experiments.


title:
On matrix realizations of the contact superconformal algebra
  $\hat{K}'(4)$ and the exceptional N = 6 superconformal algebra

abstract:
  The superalgebra $\hat{K}'(4)$ and the exceptional N = 6 superconformal
algebra have ``small'' irreducible representations in the superspaces $V^{\mu}
= t^{\mu}\C[t, t^{-1}]\otimes\Lambda(N)$, where N = 2 and 3, respectively. For
${\mu \in \C\backslash \Z}$ they are associated to the embeddings of these
superalgebras into the Lie superalgebras of pseudodifferential symbols on the
supercircle S^{1|N}. In this work we describe $\hat{K}'(4)$ and the exceptional
N = 6 superconformal algebra in terms of matrices over a Weyl algebra.
Correspondingly, we obtain realizations of their representations in $V^{\mu}$
for $\mu = 0$.


title: Rare K- (vs.) B-decays

abstract:
  We present a concise review of the recent theoretical progress concerning the
standard model calculations of the rare K_L -> pi^0 nu anti-nu, K^+ -> pi^+ nu
anti-nu (gamma), anti-B -> X_s gamma, and anti-B -> X_s l^+ l^- decays. The
current status and future of the model-independent analysis of rare K- and
B-meson decays within constrained minimal-flavor-violation is also briefly
discussed.


title: Existence of a Density Functional for an Intrinsic State

abstract:
  A generalization of the Hohenberg-Kohn theorem proves the existence of a
density functional for an intrinsic state, symmetry violating, out of which a
physical state with good quantum numbers can be projected.


title: Two-particle correlations with strange baryons and mesons at RHIC

abstract:
  We present results on two-particle correlations using singly-strange
particles ($\Lambda$, $\bar{\Lambda}$, $K^0_S$) and charged hadrons at
intermediate p_T in d+Au and Au+Au collisions at RHIC. We discuss properties of
the near-side correlation peak in both azimuthal and pseudo-rapidity space and
separate jet-like contributions from the long-range pseudo-rapidity
correlations (the ridge). In particular, we study the centrality and p_T
dependence of the jet and ridge yields for various trigger and associated
particle species and compare the results to model predictions.


title: Excision without excision: the relativistic turducken

abstract:
  to turducken (turduckens, turduckening, turduckened, turduckened) [math.]: To
stuff a black hole. We analyze and apply an alternative to black hole excision
based on smoothing the interior of black holes with arbitrary - possibly
constraint violating - initial data, and solving the vacuum Einstein evolution
equations everywhere. By deriving the constraint propagation system for our
hyperbolic formulation of the BSSN evolution system we rigorously prove that
the constraints propagate causally and so any constraint violations introduced
inside the black holes cannot affect the exterior spacetime. (This does not
follow from the causal structure of the spacetime as is often assumed.) We
present numerical evolutions of Cook-Pfeiffer binary black hole initial
configurations showing that these techniques appear to work robustly for
generic data. We also present numerical evidence from spherically symmetric
evolutions that for the gauge conditions used the same stationary end-state is
approached irrespective of the choice of initial data and smoothing procedure.


title: Clustering, Chaos and Crisis in a Bailout Embedding Map

abstract:
  We study the dynamics of inertial particles in two dimensional incompressible
flows. The particle dynamics is modelled by four dimensional dissipative
bailout embedding maps of the base flow which is represented by 2-d area
preserving maps. The phase diagram of the embedded map is rich and interesting
both in the aerosol regime, where the density of the particle is larger than
that of the base flow, as well as the bubble regime, where the particle density
is less than that of the base flow. The embedding map shows three types of
dynamic behaviour, periodic orbits, chaotic structures and mixed regions. Thus,
the embedding map can target periodic orbits as well as chaotic structures in
both the aerosol and bubble regimes at certain values of the dissipation
parameter. The bifurcation diagram of the 4-d map is useful for the
identification of regimes where such structures can be found. An attractor
merging and widening crisis is seen for a special region for the aerosols. At
the crisis, two period-10 attractors merge and widen simultaneously into a
single chaotic attractor. Crisis induced intermittency is seen at some points
in the phase diagram. The characteristic times before bursts at the crisis show
power law behaviour as functions of the dissipation parameter. Although the
bifurcation diagram for the bubbles looks similar to that of aerosols, no such
crisis regime is seen for the bubbles. Our results can have implications for
the dynamics of impurities in diverse application contexts.


title: Batalin-Vilkovisky algebras and the J-homomorphism

abstract:
  Let X be a topological space. The homology of the iterated loop space
$H_*\Omega^n X$ is an algebra over the homology of the framed n-disks operad
$H_*f\mathcal{D}_n$ \cite{Getzler:BVAlg,Salvatore-Wahl:FrameddoBVa}. We
determine completely this $H_*f\mathcal{D}_n$-algebra structure on
  $H_*(\Omega^n X;\mathbb{Q})$. We show that the action of $H_*(SO(n))$ on the
iterated loop space $H_*\Omega^n X$ is related to the J-homomorphism and that
the BV-operator vanishes on spherical classes only in characteristic other than
2.


title: The 2-adic valuations of Stirling numbers

abstract:
  The 2-adic valuation of the Stirling numbres is examined. We conjecture
pattrens about the distributions of these valuations in residue classes modulo
powers of 2.


title: AdS spacetimes from wrapped D3-branes

abstract:
  We derive a geometrical characterisation of a large class of AdS_3 and AdS_2
supersymmetric spacetimes in IIB supergravity with non-vanishing five-form flux
using G-structures. These are obtained as special cases of a class of
supersymmetric spacetimes with an $\mathbb{R}^{1,1}$ or $\mathbb{R}$ (time)
factor that are associated with D3-branes wrapping calibrated 2- or 3- cycles,
respectively, in manifolds with SU(2), SU(3), SU(4) and G_2 holonomy. We show
how two explicit AdS solutions, previously constructed in gauged supergravity,
satisfy our more general G-structure conditions. For each explicit solution we
also derive a special holonomy metric which, although singular, has an
appropriate calibrated cycle. After analytic continuation, some of the classes
of AdS spacetimes give rise to known classes of BPS bubble solutions with
$\mathbb{R}\times SO(4)\times SO(4)$, $\mathbb{R}\times SO(4)\times U(1)$, and
$\mathbb{R}\times SO(4)$ symmetry. These have 1/2, 1/4 and 1/8 supersymmetry,
respectively. We present a new class of 1/8 BPS geometries with
$\mathbb{R}\times SU(2)$ symmetry, obtained by analytic continuation of the
class of AdS spacetimes associated with D3-branes wrapped on associative
three-cycles.


title:
A Global View of Cognitive Structure and Implications for Instruction
  and Assessment

abstract:
  We assert that models of cognitive structure all have the same basic
features. These basic features, independent of the model, have important
implications for instruction and assessment. We describe the basic features of
models of cognitive structure, giving examples from our research. We then
discuss the implications for instruction and assessment.


title:
A Study of the Vertical Motion of Supernova Remnant Bubbles in the
  Interstellar Medium Drawn from the Results of Three-Dimensional MHD
  Simulations

abstract:
  In order to determine the circumstances under which isolated SNRs are capable
of rising into and enriching the thick disk and galactic halo, simulations of
supernova remnants are performed with the FLASH magnetohydrodynamic code. We
performed simulations in which the interstellar magnetic field is parallel to
or perpendicular to the galactic plane as well as a simulation without a
magnetic field. The ambient gas density distribution and gravitational
potential are based on observations of our galaxy. We evolve the remnants to
ages of roughly 10,000,000 years. For our simulation without a magnetic field,
we compare the evolution of the hot bubble's velocity with the velocity
evolution calculated from the buoyant and drag accelerations. We found
surprisingly small vertical velocities of the hot gas, from which we estimated
the drag coefficient to be ten for the non-magnetic simulation. Although we
found little buoyant motion of the hot gas during the remnant's lifetime, we
found rapid vertical motion of the associated cool dense gas near the end of
the remnants life. This motion deformed the remnant into a mushroom cloud
structure similar to those found in previous simulations. The simulation in
which we have a 4 micro-Gauss magnetic field parallel to the galactic mid-plane
shows a dramatically elongated bubble parallel to the magnetic field. The
magnetic field pins the supernova remnant preventing it from rising. In the
simulation with the 4 micro-Gauss magnetic field perpendicular to the midplane
the hot bubble rises more, indicating that having the magnetic field in the
same direction as the gravitational force enhances the rise of the bubble.


title: Quantized symplectic actions and W-algebras

abstract:
  With a nilpotent element in a semisimple Lie algebra g one associates a
finitely generated associative algebra W called a W-algebra of finite type.
This algebra is obtained from the universal enveloping algebra U(g) by a
certain Hamiltonian reduction. We observe that W is the invariant algebra for
an action of a reductive group G with Lie algebra g on a quantized symplectic
affine variety and use this observation to study W. Our results include an
alternative definition of W, a relation between the sets of prime ideals of W
and of the corresponding universal enveloping algebra, the existence of a
one-dimensional representation of W in the case of classical g and the
separation of elements of W by finite dimensional representations.


title: Dynamic Boundaries of Event Horizon Magnetospheres

abstract:
  This Letter analyzes 3-dimensional simulations of Kerr black hole
magnetospheres that obey the general relativistic equations of perfect
magnetohydrodynamics (MHD). Particular emphasis is on the event horizon
magnetosphere (EHM) which is defined as the the large scale poloidal magnetic
flux that threads the event horizon of a black hole (This is distinct from the
poloidal magnetic flux that threads the equatorial plane of the ergosphere,
which forms the ergospheric disk magnetosphere). Standard MHD theoretical
treatments of Poynting jets in the EHM are predicated on the assumption that
the plasma comprising the boundaries of the EHM plays no role in producing the
Poynting flux. The energy flux is electrodynamic in origin and it is
essentially conserved from the horizon to infinity, this is known as the
Blandford-Znajek (B-Z) mechanism. To the contrary, within the 3-D simulations,
the lateral boundaries are strong pistons for MHD waves and actually inject
prodigious quantities of Poynting flux into the EHM. At high black hole spin
rates, strong sources of Poynting flux adjacent to the EHM from the ergospheric
disk will actually diffuse to higher latitudes and swamp any putative B-Z
effects. This is in contrast to lower spin rates, which are characterized by
much lower output powers and modest amounts of Poynting flux are injected into
the EHM from the accretion disk corona.


title: Wetting Properties of Grain Boundaries in Solid Helium 4

abstract:
  We have observed boundaries between hcp $^4$He crystal grains in equilibrium
with liquid $^4$He. We have found that, when emerging at the liquid-solid
interface, a grain boundary makes a groove whose dihedral angle $2\theta$ is
non-zero. This measurement shows that grain boundaries are not completely wet
by the liquid phase, in agreement with recent Monte Carlo simulations.
Depending on the value of $\theta$, the contact line of a grain boundary with a
solid wall may be wet by the liquid. In this case, the line is a thin channel
with a curved triangular cross section, whose measured width agrees with
predictions from a simple model. We discuss these measurements in the context
of grain boundary premelting and for a future understanding of the possible
supersolidity of solid $^4$He.


title: Nonperturbative resonant strong field ionization of atomic hydrogen

abstract:
  We investigate resonant strong field ionization of atomic hydrogen with
respect to the 1s-2p-transition. By "strong" we understand that Rabi-periods
are executed on a femtosecond time scale. Ionization and AC Stark shifts modify
the bound state dynamics severely, leading to nonperturbative signatures in the
photoelectron spectra. We introduce an analytical model, capable of predicting
qualitative features in the photoelectron spectra such as the positions of the
Autler-Townes peaks for modest field strengths. Ab initio solutions of the
time-dependent Schroedinger equation show a pronounced shift and broadening of
the left Autler-Townes peak as the field strength is increased. The right peak
remains rather narrow and shifts less. This result is analyzed and explained
with the help of exact AC Stark shifts and ionization rates obtained from
Floquet theory. Finally, it is demonstrated that in the case of finite pulses
as short as 20fs the Autler-Townes duplet can still be resolved. The fourth
generation light sources under construction worldwide will provide bright,
coherent radiation with photon energies ranging from a tenth of a meV up to
tens of keV, hence covering the regime studied in the paper so that
measurements of nonperturbative, relative AC Stark shifts should become
feasible with these new light sources.


title:
The Ba2LnFeNb4O15 Tetragonal Tungsten Bronze: towards RT composite
  multiferroics

abstract:
  Several Niobium oxides of formula Ba2LnFeNb4O15 (Ln = La, Pr, Nd, Sm, Eu, Gd)
with the Tetragonal Tungsten Bronze (TTB) structure have been synthesised by
conventional solid-state methods. The Neodymium, Samarium and Europium
compounds are ferroelectric with Curie temperature ranging from 320 to 440K.
The Praseodymium and Gadolinium compounds behave as relaxors below 170 and 300
K respectively. The Praseodymium, Neodymium, Samarium, Europium and Gadolinium
compounds exhibit magnetic hysteresis loops at room temperature originating
from traces of a barium ferrite secondary phase. The presence of both
ferroelectric and magnetic hysteresis loops at room temperature allows
considering these materials as composites multiferroic. Based on
crystal-chemical analysis we propose some relationships between the
introduction of Ln3+ ions in the TTB framework and the chemical, structural and
physical properties of these materials.


title: Excitons in Silicon Nanocrystalites: The Nature of Luminescence

abstract:
  The absorption and emission spectra of silicon nanocrystals up to 1 nm
diameter including geometry optimization and the many-body effects induced by
the creation of an electron-hole pair have been calculated within a
first-principles framework. Starting from hydrogenated silicon clusters of
different size, different Si/O bonding at the cluster surface have been
considered. We found that the presence of a Si-O-Si bridge bond originates
significative excitonic luminescence features in the visible range that are in
fair agreement with the experimental outcomes.


title:
On the possibility of extending the Nore-Frenkel generalized law of
  correspondent states to non-isotropic patchy interactions

abstract:
  Colloidal systems (and protein solutions) are often characterized by
attractive interactions whose range is much smaller than the particle size.
When this is the case and the interaction is spherical, systems obey a
generalized law of correspondent states (GLCS), first proposed by Noro and
Frenkel [ J.Chem.Phys. 113, 2941 (2000) ]. The thermodynamic properties become
insensitive to the details of the potential, depending only on the value of the
second virial coefficient B_2 and the density $\rho$. The GLCS does not
generically hold for the case of non-spherical potentials. In this Letter we
suggest that when particles interact via short-ranged small-angular amplitude
patchy interactions (so that the condition of only one bond per patch is
fulfilled) it is still possible to generalize the GLCS close to the liquid-gas
critical point. Keywords: Colloids, Second Virial Coefficient, Proteins
interactions, Short-ranged attractive attractions.


title: B(H) lattices, density and arithmetic mean ideals

abstract:
  This part of a multi-paper project studies the lattice properties of the
arithmetic mean ideals of B(H) introduced by Dykema, Figiel, Weiss, and
Wodzicki. We prove: the lattices of all principal ideals, of arithmetic mean or
arithmetic mean at infinity stable principal ideals or of principal ideals with
a generator that satisfies the Delta_1/2 condition, are all both upper and
lower dense in the lattice of general ideals. That is, between any ideal and an
ideal (nested above or below respectively) in one of these sublattices, lies
another ideal in that sublattice. Among the applications: a principal ideal I
is am-stable (I = I_a) if and only if any of its first order arithmetic mean
ideals are am-stable if and only if the ideal satisfies the first order
equality cancellation property: J_a = I_a implies J = I. We show that this
cancellation property can fail even for am-stable countably generated ideals.
Similar results hold for arithmetic mean at infinity ideals. Inclusion
cancellations do not hold in general even for principal ideals, but for every
ideal I there is a largest ideal I^ for which J_a contains I_a implies that J
contains I^. When I is principal, I^ too is principal. We show that I=I^ is a
strictly stronger property than am-stability. For example, for I the p < 1
power of the principal ideal J generated by diag {1/n}, I^ is the q power of J
where 1/p-1/q = 1.


title:
The action of the mapping class group on representation varieties of
  PSL(2,R). Case I: The one-holed torus

abstract:
  In this paper we consider the action of the mapping class group of a surface
on the space of homomorphisms from the fundamental group of a surface into
PSL(2,R). Goldman conjectured that when the surface is closed and of genus
bigger than one, the action on non-Teichmuller connected components of the
associated moduli space (i.e. the space of homomorphisms modulo conjugation) is
ergodic. One approach to this question is to use sewing techniques which
requires that one considers the action on the level of homomorphisms, and for
surfaces with boundary. In this paper we consider the case of the one-holed
torus with boundary condition, and we determine regions where the action is
ergodic. Our main result mirrors a theorem of Goldman's at the level of moduli.


title: Cavity cooling of a nanomechanical resonator by light scattering

abstract:
  We present a novel method for opto-mechanical cooling of sub-wavelength sized
nanomechanical resonators. Our scheme uses a high finesse Fabry-Perot cavity of
small mode volume, within which the nanoresonator is acting as a
position-dependant perturbation by scattering. In return, the back-action
induced by the cavity affects the nanoresonator dynamics and can cool its
fluctuations. We investigate such cavity cooling by scattering for a nanorod
structure and predict that ground-state cooling is within reach.


title:
The inequality between mass and angular momentum for axially symmetric
  black holes

abstract:
  In this essay I first discuss the physical relevance of the inequality $m\geq
\sqrt{|J|}$ for axially symmetric (non-stationary) black holes, where m is the
mass and J the angular momentum of the spacetime. Then, I present a proof of
this inequality for the case of one spinning black hole. The proof involves a
remarkable characterization of the extreme Kerr black hole as an absolute
minimum of the total mass. Finally, I conjecture on the physical implications
of this characterization for the non linear stability problem for black holes.


title: Spitzer observations of V4332 Sagittarii: Detection of Alumina Dust

abstract:
  We present broad-band 24, 70 and 160 micron photometry, 5-35 micron and 55-90
micron spectra of the eruptive variable V4332 Sgr from Spitzer observations.
The distinguishing feature of the 5-35 micron spectrum is an unusually broad
absorption feature near 10 micron at the position generally associated with
silicate-rich dust. Through radiative transfer modeling, we show that this
broad feature cannot arise from silicates alone but requires the inclusion of
alumina (Al2O3) as a dust condensate. The case for including Al2O3 is
strengthened further by the presence of the AlO radical, a potentially
important molecule in forming Al2O3. The present detection indicates that
porous alumina manifests itself through a broadening of the 9.7 micron silicate
feature and additionally displays, on the shoulder of the silicate feature, a
component at ~11.5 micron. We discuss how further observations of V4332 Sgr may
have the potential of verifying some general predictions of the dust
condensation process.


title:
The radical character of the acenes: A density matrix renormalization
  group study

abstract:
  We present a detailed investigation of the acene series using high-level
wavefunction theory. Our ab-initio Density Matrix Renormalization Group
algorithm has enabled us to carry out Complete Active Space calculations on the
acenes from napthalene to dodecacene correlating the full pi-valence space.
  While we find that the ground-state is a singlet for all chain-lengths,
examination of several measures of radical character, including the natural
orbitals, effective number of unpaired electrons, and various correlation
functions, suggests that the longer acene ground-states are polyradical in
nature.


title: Targeted Excited State Algorithms

abstract:
  To overcome the limitations of the traditional state-averaging approaches in
excited state calculations, where one solves for and represents all states
between the ground state and excited state of interest, we have investigated a
number of new excited state algorithms. Building on the work of van der Vorst
and Sleijpen (SIAM J. Matrix Anal. Appl., 17, 401 (1996)), we have implemented
Harmonic Davidson and State-Averaged Harmonic Davidson algorithms within the
context of the Density Matrix Renormalization Group (DMRG). We have assessed
their accuracy and stability of convergence in complete active space DMRG
calculations on the low-lying excited states in the acenes ranging from
naphthalene to pentacene. We find that both algorithms offer increased accuracy
over the traditional State-Averaged Davidson approach, and in particular, the
State-Averaged Harmonic Davidson algorithm offers an optimal combination of
accuracy and stability in convergence.


title: On unitarily equivalent submodules

abstract:
  The Hardy space on the unit ball in C^n provides examples of a quasi-free,
finite rank Hilbert module which contains a pure submodule isometrically
isomorphic to the module itself. For n=1 the submodule has finite codimension.
In this note we show that this phenomenon can only occur for modules over
domains in the complex plain and for finitely-connected domains only for
Hardy-like spaces, the bundle shifts. Moreover, we show for essentially
reductive modules that even when the codimension is infinite, the module is
subnormal and again, on nice domains such as the unit ball, must be Hardy-like.


title:
The three dimensional skeleton: tracing the filamentary structure of the
  universe

abstract:
  The skeleton formalism aims at extracting and quantifying the filamentary
structure of the universe is generalized to 3D density fields; a numerical
method for computating a local approximation of the skeleton is presented and
validated here on Gaussian random fields. This method manages to trace well the
filamentary structure in 3D fields such as given by numerical simulations of
the dark matter distribution on large scales and is insensitive to monotonic
biasing. Two of its characteristics, namely its length and differential length,
are analyzed for Gaussian random fields. Its differential length per unit
normalized density contrast scales like the PDF of the underlying density
contrast times the total length times a quadratic Edgeworth correction
involving the square of the spectral parameter. The total length scales like
the inverse square smoothing length, with a scaling factor given by 0.21 (5.28+
n) where n is the power index of the underlying field. This dependency implies
that the total length can be used to constrain the shape of the underlying
power spectrum, hence the cosmology. Possible applications of the skeleton to
galaxy formation and cosmology are discussed. As an illustration, the
orientation of the spin of dark halos and the orientation of the flow near the
skeleton is computed for dark matter simulations. The flow is laminar along the
filaments, while spins of dark halos within 500 kpc of the skeleton are
preferentially orthogonal to the direction of the flow at a level of 25%.


title:
The Continuing Saga of the Explosive Event(s) in the M87 Jet: Is M87 a
  Blazar?

abstract:
  We review the recent data on the knot HST-1 in the M87 jet in the context of
typical blazar behavior. In particular we discuss the wide-band flare of 2005
which peaked at a factor of 50 to 80 times the intensity observed in 2000; the
superluminal radio features; and the arguments that support the hypothesis that
HST-1 was the source of the excess TeV emission found by H.E.S.S. in 2005. To
the extent that M87 can be classified as a blazar, perhaps observed at a
somewhat larger angle to the line of sight compared to most blazars, all of
these blazar properties originate at a distance greater than 100 pc from the
nucleus, and thus cannot be associated with the location of the 'launching of
the jet'.


title:
Effective actions and N=1 vacuum conditions from SU(3) x SU(3)
  compactifications

abstract:
  We consider compactifications of type II string theory on general SU(3) x
SU(3) structure backgrounds allowing for a very large set of fluxes, possibly
nongeometric ones. We study the effective 4d low energy theory which is a
gauged N=2 supergravity, and discuss how its data are obtained from the
formalism of the generalized geometry on T+T*. In particular we relate
Hitchin's special Kaehler metrics on the spaces of even and odd pure spinors to
the metric on the supergravity moduli space of internal metric and B-field
fluctuations. We derive the N=1 vacuum conditions from this N=2 effective
action, as well as from its N=1 truncation. We prove a direct correspondence
between these conditions and an integrated version of the pure spinor equations
characterizing the N=1 backgrounds at the ten dimensional level.


title: Stringy Instantons and Cascading Quivers

abstract:
  D-brane instantons can perturb the quantum field theories on space-time
filling D-branes by interesting operators. In some cases, these D-brane
instantons are novel "stringy" effects (not interpretable directly as instanton
effects in the low-energy quantum field theory), while in others the D-brane
instantons can be directly interpreted as field theory effects. In this note,
we describe a situation where both perspectives are available, by studying
stringy instantons in quivers which arise at simple Calabi-Yau singularities.
We show that a stringy instanton which wraps an unoccupied node of the quiver,
and gives rise to a non-perturbative mass in the space-time field theory, can
be reinterpreted as a conventional gauge theory effect by going up in an
appropriate renormalization group cascade. Interestingly, in the cascade, the
contribution of the stringy instanton does not come from gauge theory
instantons but from strong coupling dynamics.


title:
Incommensurate Charge Order Phase in Fe2OBO3 due to Geometrical
  Frustration

abstract:
  The temperature dependence of charge order in Fe2OBO3 was investigated by
resistivity and differential scanning calorimetry measurements, Mossbauer
spectroscopy, and synchrotron x-ray scattering, revealing an intermediate phase
between room temperature and 340 K, characterized by coexisting mobile and
immobile carriers, and by incommensurate superstructure modulations with
temperature-dependent propagation vector (1/2,0,tau). The incommensurate
modulations arise from specific anti-phase boundaries with low energy cost due
to geometrical charge frustration.


title: A canonical transformation theory from extended normal ordering

abstract:
  The Canonical Transformation theory of Yanai and Chan [J. Chem. Phys. 124,
194106 (2006)] provides a rigorously size-extensive description of dynamical
correlation in multireference problems. Here we describe a new formulation of
the theory based on the extended normal ordering procedure of Mukherjee and
Kutzelnigg [J. Chem. Phys. 107, 432 (1997)].
  On studies of the water, nitrogen, and iron-oxide potential energy curves,
the Linearised Canonical Transformation Singles and Doubles theory is
competitive in accuracy with some of the best multireference methods, such as
the Multireference Averaged Coupled Pair Functional, while computational
timings (in the case of the iron-oxide molecule) are two-three orders of
magnitude faster and comparable to those of Complete Active Space Second-Order
Perturbation Theory. The results presented here are greatly improved both in
accuracy and in cost over our earlier study as the result of a new numerical
algorithm for solving the amplitude equations.


title: Deformed Macdonald-Ruijsenaars operators and super Macdonald polynomials

abstract:
  It is shown that the deformed Macdonald-Ruijsenaars operators can be
described as the restrictions on certain affine subvarieties of the usual
Macdonald-Ruijsenaars operator in infinite number of variables. The ideals of
these varieties are shown to be generated by the Macdonald polynomials related
to Young diagrams with special geometry. The super Macdonald polynomials and
their shifted version are introduced, the combinatorial formulas for them are
given.


title:
Angular momentum projection of cranked Hartree-Fock states: Application
  to terminating bands in A~44 nuclei

abstract:
  We present the first systematic calculations based on the angular-momentum
projection of cranked Slater determinants. We propose the Iy --> I scheme, by
which one projects the angular momentum I from the 1D cranked state constrained
to the average spin projection of <I_y>=I. Calculations performed for the
rotational band in 46Ti show that the AMP Iy --> I scheme offers a natural
mechanism for correcting the cranking moment of inertia at low-spins and
shifting the terminating state up by ~2 MeV, in accordance with data. We also
apply this scheme to high-spin states near the band termination in A~44 nuclei,
and compare results thereof with experimental data, shell-model calculations,
and results of the approximate analytical symmetry-restoration method proposed
previously.