title: An intrinsic characterization of the Kerr metric

abstract:
  We give the necessary and sufficient (local) conditions for a metric tensor
to be the Kerr solution. These conditions exclusively involve explicit
concomitants of the Riemann tensor.


title: Intermittency on catalysts: three-dimensional simple symmetric exclusion

abstract:
  We continue our study of intermittency for the parabolic Anderson model
$\partial u/\partial t = \kappa\Delta u + \xi u$ in a space-time random medium
$\xi$, where $\kappa$ is a positive diffusion constant, $\Delta$ is the lattice
Laplacian on $\Z^d$, $d \geq 1$, and $\xi$ is a simple symmetric exclusion
process on $\Z^d$ in Bernoulli equilibrium. This model describes the evolution
of a \emph{reactant} $u$ under the influence of a \emph{catalyst} $\xi$.
  In G\"artner, den Hollander and Maillard (2007) we investigated the behavior
of the annealed Lyapunov exponents, i.e., the exponential growth rates as
$t\to\infty$ of the successive moments of the solution $u$. This led to an
almost complete picture of intermittency as a function of $d$ and $\kappa$. In
the present paper we finish our study by focussing on the asymptotics of the
Lyaponov exponents as $\kappa\to\infty$ in the \emph{critical} dimension $d=3$,
which was left open in G\"artner, den Hollander and Maillard (2007) and which
is the most challenging. We show that, interestingly, this asymptotics is
characterized not only by a \emph{Green} term, as in $d\geq 4$, but also by a
\emph{polaron} term. The presence of the latter implies intermittency of
\emph{all} orders above a finite threshold for $\kappa$.


title:
Ultimate synchrotron cutoff in gamma-ray spectra of blazars as a
  signature of the converter mechanism

abstract:
  There is a robust upper limit on the energy of synchrotron radiation in
high-energy astrophysics: $ \sim m_{\rm e} c^2 /\alpha$, where $\alpha = 1/137$
is the fine structure constant and the value refers to the comoving frame of
the fluid. This is the maximal energy of synchrotron photons which can be
emitted by an electron having an arbitrarily high initial energy after it turns
by angle $\sim \pi$ in the magnetic field. This upper limit can be naturally
reached if the converter mechanism contributes to the jet radiation and can be
imprinted in spectra of some blazars as a cutoff or a dip in the GeV range. We
use numerical simulations to probe the range of parameters of a radiating jet
where the ultimate synchrotron cutoff appears. We reproduce the variety of
spectra depending on the source luminosity and on the scale of the emission
site. We also compare our results with the EGRET blazar spectra in order to
illustrate that agreement is possible but still not statistically significant.
The predicted feature, if it exists, should be observed by {\it Fermi} in
spectra of some blazars.


title: Generic modes of consensus formation in stochastic language dynamics

abstract:
  We introduce a class of stochastic models for the dynamics of two linguistic
variants that are competing to become the single, shared convention within an
unstructured community of speakers. Different instances of the model are
distinguished by the way agents handle variability in the language (i.e.,
multiple forms for the same meaning). The class of models includes as special
cases two previously-studied models of language dynamics, the Naming Game, in
which agents tend to standardise on variants they have encountered most
frequently, and the Utterance Selection Model, in which agents tend to preserve
variability by uniform sampling of a pool of utterances. We reduce the full
complexities of the dynamics to a single-coordinate stochastic model which
allows the probability and time taken for speakers to reach consensus on a
single variant to be calculated for large communities. This analysis suggests
that in the broad class of models considered, consensus is formed in one of
three generic ways, according to whether agents tend to eliminate, accentuate
or sample neutrally the variability in the language. These different regimes
are observed in simulations of the full dynamics, and for which the simplified
model in some cases makes good quantitative predictions. We use these results,
along with comparisons with related models, to conjecture the likely behaviour
of more general models, and further make use of empirical data to argue that in
reality, biases away from neutral sampling behaviour are likely to be small.


title:
Mott Scattering of polarized electrons in a circularly polarized laser
  field

abstract:
  We present a study of Mott scattering of polarized electrons in the presence
of a laser field with circular polarization using the helicity formalism and
the introduction of the well known concept of non flip differential cross
section as well as that of flip differential cross section. The results we have
obtained in the presence of a laser field are coherent with those obtained in
the absence of a laser field. We have studied the relativistic regime as well
as the non relativistic regime that are precisely defined in the text. Two
important consistency checks have been carried out successfully. The first one
is that the sum of both differential cross sections (one with spin up, the
other with spin down) always gives the unpolarized differential cross section.
The second one is that the relativistic unpolarized differential cross section
converges to the non relativistic differential cross section in the limit of
small velocities. Moreover, the results obtained using the sofware Reduce
\cite{8} gave rise to non contracted coefficients that have been dealt with
using the geometry chosen.


title: K\"ahlerian Twistor Spinors

abstract:
  On a K\"ahler spin manifold K\"ahlerian twistor spinors are a natural
analogue of twistor spinors on Riemannian spin manifolds. They are defined as
sections in the kernel of a first order differential operator adapted to the
K\"ahler structure, called K\"ahlerian twistor (Penrose) operator. We study
K\"ahlerian twistor spinors and give a complete description of compact K\"ahler
manifolds of constant scalar curvature admitting such spinors. As in the
Riemannian case, the existence of K\"ahlerian twistor spinors is related to the
lower bound of the spectrum of the Dirac operator.


title: Singular Riemannian Foliations: Exceptional Leaves; Tautness

abstract:
  For a singular Riemannian foliation whose leaves are properly embedded, we
show in the first part of this article the existence of global tubular
neighbourhoods, and we develop a global description of the foliation as
stratification by types of leaves.
  The second part deals with the further restriction to a foliation without
horizontal conjugate points, introduced by Lytchak and Thorbergsson, which in
the special case of an isometric group action equals the concept of
variationally completeness. Therefrom, we deduce a global geometric description
-- the focal points of the leaves are exactly the singular points -- as well as
a topological one: tautness of the leaves.


title: Purely nonlocal Hamiltonian formalism for systems of hydrodynamic type

abstract:
  We study purely nonlocal Hamiltonian structures for systems of hydrodynamic
type. In the case of a semi-Hamiltonian system, we show that such structures
are related to quadratic expansions of the diagonal metrics naturally
associated with the system.


title:
On the Global Behavior of Solutions to a Planar System of Difference
  Equations

abstract:
  We establish the relation between local stability of equilibria and slopes of
critical curves for a specific class of difference equations. We then use this
result to give global behavior results for nonnegative solutions of the system
of difference equations \begin{equation*} %\tag{LGIN} \begin{array}{rcl}
x_{n+1} & = & \displaystyle \frac{b_1 x_n}{1+x_n+c_1 y_{n}} +h_1 y_{n+1} & = &
\displaystyle \frac{b_2 y_n}{1+y_n+c_2 x_{n}} +h_2 \end{array} \quad n=0,1,...,
\quad (x_0,y_0) \in [0,\infty)\times [0,\infty) \end{equation*} with positive
parameters. In particular, we show that the system has between one and three
equilibria, and that the number of equilibria determines global behavior as
follows: if there is only one equilibrium, then it is globally asymptotically
stable. If there are two equilibria, then one is a local attractor and the
other one is nonhyperbolic. If there are three equilibria, then they are
linearly ordered in the south-east ordering of the plane, and consist of a
local attractor, a saddle point, and another local attractor. Finally, we give
sufficient conditions for having a unique equilibrium.


title:
Possible effect of collective modes in zero magnetic field transport in
  an electron-hole bilayer

abstract:
  We report single layer resistivities of 2-dimensional electron and hole gases
in an electron-hole bilayer with a 10nm barrier. In a regime where the
interlayer interaction is stronger than the intralayer interaction, we find
that an insulating state ($d\rho/dT < 0$) emerges at $T\sim1.5{\rm K}$ or
lower, when both the layers are simultaneously present. This happens deep in
the $"$metallic" regime, even in layers with $k_{F}l>500$, thus making
conventional mechanisms of localisation due to disorder improbable. We suggest
that this insulating state may be due to a charge density wave phase, as has
been expected in electron-hole bilayers from the Singwi-Tosi-Land-Sj\"olander
approximation based calculations of L. Liu {\it et al} [{\em Phys. Rev. B},
{\bf 53}, 7923 (1996)]. Our results are also in qualitative agreement with
recent Path-Integral-Monte-Carlo simulations of a two component plasma in the
low temperature regime [ P. Ludwig {\it et al}. {\em Contrib. Plasma Physics}
{\bf 47}, No. 4-5, 335 (2007)]


title: Non-ergodicity of Nose-Hoover dynamics

abstract:
  The numerical integration of the Nose-Hoover dynamics gives a deterministic
method that is used to sample the canonical Gibbs measure. The Nose-Hoover
dynamics extends the physical Hamiltonian dynamics by the addition of a
"thermostat" variable, that is coupled nonlinearly with the physical variables.
The accuracy of the method depends on the dynamics being ergodic. Numerical
experiments have been published earlier that are consistent with non-ergodicity
of the dynamics for some model problems. The authors recently proved the
non-ergodicity of the Nose-Hoover dynamics for the one-dimensional harmonic
oscillator.
  In this paper, this result is extended to non-harmonic one-dimensional
systems. It is also shown for some multidimensional systems that the averaged
dynamics for the limit of infinite thermostat "mass" have many invariants, thus
giving theoretical support for either non-ergodicity or slow ergodization.
Numerical experiments for a two-dimensional central force problem and the
one-dimensional pendulum problem give evidence for non-ergodicity.


title:
Minimum entropy production closure of the photo-hydrodynamic equations
  for radiative heat transfer

abstract:
  In the framework of a two-moment photo-hydrodynamic modelling of radiation
transport, we introduce a concept for the determination of effective radiation
transport coefficients based on the minimization of the local entropy
production rate of radiation and matter. The method provides the nonequilibrium
photon distribution from which the effective absorption coefficients and the
variable Eddington factor (VEF) can be calculated. The photon distribution
depends on the frequency dependence of the absorption coefficient, in contrast
to the distribution obtained by methods based on entropy maximization. The
calculated mean absorption coefficients are not only correct in the limit of
optically thick and thin media, but even provide a reasonable interpolation in
the cross-over regime between these limits, notably without introducing any fit
parameter. The method is illustrated and discussed for grey matter and for a
simple example of non-grey matter with a two-band absorption spectrum. The
method is also briefly compared with the maximum entropy concept.

categories: cond-mat.stat-mech astro-ph cond-mat.other physics.ao-ph


title: Freudenthal triple classification of three-qubit entanglement

abstract:
  We show that the three-qubit entanglement classes: (0) Null, (1) Separable
A-B-C, (2a) Biseparable A-BC, (2b) Biseparable B-CA, (2c) Biseparable C-AB, (3)
W and (4) GHZ correspond respectively to ranks 0, 1, 2a, 2b, 2c, 3 and 4 of a
Freudenthal triple system defined over the Jordan algebra C+C+C. We also
compute the corresponding SLOCC orbits.


title: On the solutions of the second heavenly and Pavlov equations

abstract:
  We have recently solved the inverse scattering problem for one parameter
families of vector fields, and used this result to construct the formal
solution of the Cauchy problem for a class of integrable nonlinear partial
differential equations connected with the commutation of multidimensional
vector fields, like the heavenly equation of Plebanski, the dispersionless
Kadomtsev - Petviashvili (dKP) equation and the two-dimensional dispersionless
Toda (2ddT) equation, as well as with the commutation of one dimensional vector
fields, like the Pavlov equation. We also showed that the associated
Riemann-Hilbert inverse problems are powerfull tools to establish if the
solutions of the Cauchy problem break at finite time,to construct their
longtime behaviour and characterize classes of implicit solutions. In this
paper, using the above theory, we concentrate on the heavenly and Pavlov
equations, i) establishing that their localized solutions evolve without
breaking, unlike the cases of dKP and 2ddT; ii) constructing the longtime
behaviour of the solutions of their Cauchy problems; iii) characterizing a
distinguished class of implicit solutions of the heavenly equation.


title:
Determination of the Dalitz plot parameter alpha for the decay
  eta->3pi^0 with the Crystal Ball at MAMI-B

abstract:
  A precise measurement of the Dalitz plot parameter, alpha, for the eta->3pi^0
decay is presented. The experiment was performed with the Crystal Ball and TAPS
large acceptance photon detectors at the tagged photon beam facility of the
MAMI-B electron accelerator in Mainz. High statistics of 1.8*10^6 eta->3pi^0
events were obtained, giving the result alpha = -0.032 +/- 0.002(stat) +/-
0.002(syst).


title: Contributions to the QCD Pressure Beyond Perturbation Theory

abstract:
  In this article we report on a new proposal to treat the infrared problems of
thermal QCD by taking into account explicitly the confining influence of the
Gribov horizon. In order to make clear the possible value of such an approach,
we briefly review the most important arguments why a straightforward
perturbative description of finite-temperature QCD is unlikely to be
successful. From the infrared problems of thermal perturbation theory one can
conclude that confinement effects and bound states probably play an important
role also in the high-temperature phase.
  To set the stage we recount the supposed role of the Gribov horizon for
confinement, before we turn to the application to finite-temperature theory. In
the current approach it has been found that the contributions to the free
energy from the explicit inclusion of the horizon begin to set in at order
$g^6$ -- precisely where the infrared problems of thermal QCD lead to a
breakdown of ordinary perturbation theory.
  From the study of observables (free energy, anomaly, bulk viscosity) we also
note that for thermodynamic observables the leading order term obtained by such
an expansion in the coupling strongly deviates from the more complete numerical
solution. This can be regarded as yet another sign for general problems of
series expansions in thermal QCD.


title:
Distances between pairs of vertices and vertical profile in conditioned
  Galton--Watson trees

abstract:
  We consider a conditioned Galton-Watson tree and prove an estimate of the
number of pairs of vertices with a given distance, or, equivalently, the number
of paths of a given length.
  We give two proofs of this result, one probabilistic and the other using
generating functions and singularity analysis.
  Moreover, the second proof yields a more general estimate for generating
functions, which is used to prove a conjecture by Bousquet-Melou and Janson
saying that the vertical profile of a randomly labelled conditioned
Galton-Watson tree converges in distribution, after suitable normalization, to
the density of ISE (Integrated Superbrownian Excursion).


title: The formation of the black hole in the X-ray binary system V404 Cyg

abstract:
  Using new and archival radio data, we have measured the proper motion of the
black hole X-ray binary V404 Cyg to be 9.2+/-0.3 mas/yr. Combined with the
systemic radial velocity from the literature, we derive the full
three-dimensional heliocentric space velocity of the system, which we use to
calculate a peculiar velocity in the range 47-102 km/s, with a best fitting
value of 64 km/s. We consider possible explanations for the observed peculiar
velocity, and find that the black hole cannot have formed via direct collapse.
A natal supernova is required, in which either significant mass (approximately
11 solar masses) was lost, giving rise to a symmetric Blaauw kick of up to 65
km/s, or, more probably, asymmetries in the supernova led to an additional kick
out of the orbital plane of the binary system. In the case of a purely
symmetric kick, the black hole must have been formed with a mass of
approximately 9 solar masses, since when it has accreted 0.5-1.5 solar masses
from its companion.


title:
Measurement of the Cotton-Mouton effect in nitrogen, oxygen, carbon
  dioxide, argon, and krypton with the Q & A apparatus

abstract:
  Experiments for vacuum birefringence and vacuum dichroism have been set up
with high-finesse high magnetic experimental apparatuses, which seem to be
ideal for small gaseous Cotton-Mouton effect (CME) measurements. PVLAS
Collaboration has measured CMEs in krypton, xenon and neon at the wavelength of
1064 nm. In this Letter, we report on our measurement of CMEs in nitrogen,
oxygen, carbon dioxide, argon, and krypton at the same wavelength in a magnetic
field B = 2.3 T at pressure P = 0.5-300 Torr and temperature T = 295-298 K. Our
results agree with the PVLAS results in the common cases.


title: Distribution amplitude for the photon-pion transition

abstract:
  The exclusive production of \pi\pi and \pi\rho in hard \gamma^{\star}\gamma
scattering in the forward kinematical region where the virtual photon is highly
off-shell are studied through the \gamma\to\pi^- Transition Distribution
Amplitudes. The calculation is based on a covariant Bethe-Salpeter approach,
applied to the Nambu - Jona-Lasinio model, for the determination of the pion
bound state. In particular it is shown that the pion pole contribution produces
a large enhancement of the differential cross section for the pion pair
production with respect to previous estimates.


title:
Monte Carlo study of degenerate groundstates and residual entropy in a
  frustrated honeycomb lattice Ising model

abstract:
  We study a classical fully-frustrated honeycomb lattice Ising model using
Markov chain Monte Carlo methods and exact calculations . The Hamiltonian
realizes a degenerate ground state manifold of equal-energy states, where each
hexagonal plaquette of the lattice has one and only one frustrated bond, with
an extensive residual entropy that grows as the number of spins N. Traditional
single-spin flip Monte Carlo methods fail to sample all possible spin
configurations in this ground state efficiently, due to their separation by
large energy barriers. We develop a non-local "chain-flip" algorithm that
solves this problem, and demonstrate its effectiveness on the Ising Hamiltonian
with and without perturbative interactions. The two perturbations considered
are a slightly weakened bond, and an external magnetic field h. For some cases,
the chain-flip move is necessary for the simulation to find an ordered ground
state. In the case of the magnetic field, two magnetized ground states with
non-extensive entropy are found, and two special values of h exist where the
residual entropy again becomes extensive, scaling proportional to N ln phi,
where phi is the golden ratio.


title: Probing Dark Matter Dynamics via Earthborn Neutrinos at IceCube

abstract:
  Recent results from PAMELA and ATIC hint that O(TeV) dark matter (DM) is
annihilating, in our galactic neighborhood, predominantly to leptons. The
annihilation rate is much larger now than during freeze-out, one possible
explanation of this is a low-velocity enhancement of the annihilation cross
section. In a model independent fashion, we show that in this case the rate of
neutrino emission from the Earth, due to DM annihilation, may be greatly
enhanced while the rate from the Sun is unaltered. There is potential for
IceCube to see these earthborn neutrinos while the same parameter space will be
soon covered by direct detection experiments. Combining these near-future data
will allow extraction of valuable information about the DM sector dynamics.


title:
Jahn-Teller like origin of the tetragonal distortion in disordered Fe-Pd
  magnetic shape memory alloys

abstract:
  The electronic structure and magnetic properties of disordered
Fe$_{x}$Pd$_{100-x}$ alloys $(50 < x < 85)$ are investigated in the framework
of density functional theory using the full potential local orbital method
(FPLO). Disorder is treated in the coherent potential approximation (CPA). Our
calculations explain the experimental magnetization data. The origin of the
tetragonal distortion in the Fe-Pd magnetic shape memory alloys is found to be
a Jahn-Teller like effect which allows the system to reduce its band energy in
a narrow composition range. Prospects for an optimization of the alloys'
properties by adding third elements are discussed.


title: On the singularities of the curved n-body problem

abstract:
  We study singularities of the n-body problem in spaces of constant curvature
and generalize certain results due to Painleve, Weierstrass, and Sundman. For
positive curvature, some of our proofs use the correspondence between total
collision solutions of the original system and their orthogonal projection--a
property that offers a new method of approaching the problem in this particular
case.


title: On the restricted Verma modules at the critical level

abstract:
  We study the restricted Verma modules of an affine Kac-Moody algebra at the
critical level with special emphasis on their Jordan-H"older multiplicities.
The Feigin-Frenkel conjecture gives a formula for these multiplicities that
involves the periodic Kazhdan-Lusztig polynomials. We prove this conjecture for
all subgeneric blocks and for the case of anti-dominant simple subquotients.


title: Anharmonic Vibrational Dynamics of DNA Oligomers

abstract:
  Combining two-color infared pump-probe spectroscopy and anharmonic force
field calculations we characterize the anharmonic coupling patterns between
fingerprint modes and the hydrogen-bonded symmetric NH$_2$ stretching vibration
in adenine-thymine dA$_{20}$-dT$_{20}$ DNA oligomers. Specifically, it is shown
that the anharmonic coupling between the NH$_2$ bending and the CO stretching
vibration, both absorbing around 1665 cm-1, can be used to assign the NH$_2$
fundamental transition at 3215 cm-1 despite the broad background absorption of
water.


title: The damping of gravitational waves in dust

abstract:
  We examine a simple model of interaction of gravitational waves with matter
(primarily represented by dust). The aim is to investigate a possible damping
effect on the intensity of gravitational wave when passing through media. This
might be important for gravitational wave astronomy when the sources are
obscured by dust or molecular clouds.


title:
Recent results from the Hamiltonian approach to Yang-Mills theory in
  Coulomb gauge

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


title: Diffraction at TOTEM

abstract:
  The TOTEM experiment at the LHC measures the total proton-proton cross
section with the luminosity-independent method and the elastic proton-proton
cross-section over a wide |t|-range. It also performs a comprehensive study of
diffraction, spanning from cross-section measurements of individual diffractive
processes to the analysis of their event topologies. Hard diffraction will be
studied in collaboration with CMS taking advantage of the large common rapidity
coverage for charged and neutral particle detection and the large variety of
trigger possibilities even at large luminosities. TOTEM will take data under
all LHC beam conditions including standard high luminosity runs to maximize its
physics reach. This contribution describes the main features of the TOTEM
physics programme including measurements to be made in the early LHC runs. In
addition, a novel scheme to extend the diffractive proton acceptance for high
luminosity runs by installing proton detectors at IP3 is described.


title:
Effects of Magnetic Field Strength and Orientation on Molecular Cloud
  Formation

abstract:
  We present a set of numerical simulations addressing the effects of magnetic
field strength and orientation on the flow-driven formation of molecular
clouds. Fields perpendicular to the flows sweeping up the cloud can efficiently
prevent the formation of massive clouds but permit the build-up of cold,
diffuse filaments. Fields aligned with the flows lead to substantial clouds,
whose degree of fragmentation and turbulence strongly depends on the background
field strength. Adding a random field component leads to a "selection effect"
for molecular cloud formation: high column densities are only reached at
locations where the field component perpendicular to the flows is vanishing.
Searching for signatures of colliding flows should focus on the diffuse, warm
gas, since the cold gas phase making up the cloud will have lost the
information about the original flow direction because the magnetic fields
redistribute the kinetic energy of the inflows.


title:
What did we learn from the extremely bright gamma ray bursts 990123 and
  080319B?

abstract:
  The two brightest and so far the best studied gamma ray bursts (GRBs), 990123
and 080319B, were ordinary, highly collimated GRBs produced in a core collapse
supernova explosion within a high-density wind environment and observed from a
very near-axis viewing angle. Inverse Compton scattering (ICS) and synchrotron
radiation (SR), the two dominant radiation mechanisms in the cannonball (CB)
model of GRBs, together with the burst environment, provide a very simple and
sufficiently accurate description of the multiwavelength lightcurves of their
prompt and afterglow emissions.


title:
The structure of n-point functions of chiral primary operators in N=4
  super Yang-Mills at one-loop

abstract:
  We develop a compact representation of the one-loop n-point functions of all
chiral primary operators in planar SU(N), N=4 super Yang-Mills theory in terms
of tree-level disk correlation functions and the scalar one-loop box integral.
As a check, known results for all four-point functions and for n-point extremal
and near-extremal correlators are rederived. The result is then used to
evaluate explicitly a selection of five and six-point functions. Our findings
suggest that a general one-loop five-point function may be represented through
the minimal four-point and five-point functions of weight two operators.


title: A syzygetic approach to the smoothability of zero-dimensional schemes

abstract:
  We consider the question of which zero-dimensional schemes deform to a
collection of distinct points; equivalently, we ask which Artinian k-algebras
deform to a product of fields. We introduce a syzygetic invariant which sheds
light on this question for zero-dimensional schemes of regularity two. This
invariant imposes obstructions for smoothability in general, and it completely
answers the question of smoothability for certain zero-dimensional schemes of
low degree. The tools of this paper also lead to other results about Hilbert
schemes of points, including a characterization of nonsmoothable
zero-dimensional schemes of minimal degree in every embedding dimension d\geq
4.


title:
Convex PBW-Type Lyndon Bases and Restricted Two-parameter Quantum Groups
  of Type B

abstract:
  We construct convex PBW-type Lyndon bases for two-parameter quantum groups
U_{r,s}({so}_{2n+1}) with detailed commutation relations. It turns out that
under a certain condition, the restricted two-parameter quantum group
u_{r,s}({so}_{2n+1}) (r, s are roots of unity) is of Drinfeld double. All of
Hopf isomorphisms of u_{r,s}({so}_{2n+1}), as well as u_{r,s}({sl}_n) are
determined. Finally, necessary and sufficient conditions for
u_{r,s}({so}_{2n+1}) to be a ribbon Hopf algebra are singled out by describing
the left and right integrals.


title: Analytical distributions for stochastic gene expression

abstract:
  Gene expression is significantly stochastic making modeling of genetic
networks challenging. We present an approximation that allows the calculation
of not only the mean and variance but also the distribution of protein numbers.
We assume that proteins decay substantially slower than their mRNA and confirm
that many genes satisfy this relation using high-throughput data from budding
yeast. For a two-stage model of gene expression, with transcription and
translation as first-order reactions, we calculate the protein distribution for
all times greater than several mRNA lifetimes and thus qualitatively predict
the distribution of times for protein levels to first cross an arbitrary
threshold. If in addition the promoter fluctuates between inactive and active
states, we can find the steady-state protein distribution, which can be bimodal
if promoter fluctuations are slow. We show that our assumptions imply that
protein synthesis occurs in geometrically distributed bursts and allows mRNA to
be eliminated from a master equation description. In general, we find that
protein distributions are asymmetric and may be poorly characterized by their
mean and variance. Through maximum likelihood methods, our expressions should
therefore allow more quantitative comparisons with experimental data. More
generally, we introduce a technique to derive a simpler, effective dynamics for
a stochastic system by eliminating a fast variable.


title: Apparent horizons in D-dimensional Robinson-Trautman spacetime

abstract:
  We derive the higher dimensional generalization of Penrose-Tod equation
describing apparent horizons in Robinson-Trautman spacetimes. New results
concerning the existence and uniqueness of its solutions in four dimensions are
proven. Namely, previous results of Tod are generalized to nonvanishing
cosmological constant.


title: Theory of Spin-Transfer Torque in the Current-in-Plane Geometries

abstract:
  Two alternative current-induced switching geometries, in which the current
flows parallel to the magnet/nonmagnet interface, are investigated
theoretically using the nonequilibrium Keldysh theory. In the first geometry,
the current is perpendicular to the polarizing magnet/nonmagnet interface but
parallel to the nonmagnet/switching magnet interface (CPIP). In the second
geometry, the current is parallel to both the polarizing magnet/nonmagnet and
nonmagnet/switching magnet interfaces (CIP). Calculations for a single-orbital
tight binding model indicate that the spin current flowing parallel to the
switching magnet/nonmagnet interface can be absorbed by a lateral switching
magnet as efficiently as in the traditional current-perpendicular-to-plane
(CPP) geometry. The results of the model calculations are shown to be valid
also for experimentally relevant Co/Cu CPIP system described by fully realistic
tight binding bands fitted to an ab initio band structure. It is shown that
almost complete absorption of the incident spin current by a lateral switching
magnet occurs when the lateral dimensions of the switching magnet are of the
order of 50-100 interatomic distances, i.e., about 20nm and its height as small
as a few atomic planes. It is also demonstratedthat strong spin current
absorption in the CPIP/CIP geometry is not spoilt by the presence of a rough
interface between the switching magnet and nonmagnetic spacer. Polarization
achieved using a lateral magnet in the CIP geometry is found to be about 25% of
that in the traditional CPP geometry. The present CPIP calculations of the spin
transfer torque are also relevant to the so called pure-spin-current-induced
magnetization switching that had been recently observed.


title:
On the Solution Space of Differentially Rotating Neutron Stars in
  General Relativity

abstract:
  A highly accurate, multi-domain spectral code is used in order to construct
sequences of general relativistic, differentially rotating neutron stars in
axisymmetry and stationarity. For bodies with a spheroidal topology and a
homogeneous or an N=1 polytropic equation of state, we investigate the solution
space corresponding to broad ranges of degree of differential rotation and
stellar densities. In particular, starting from static and spherical
configurations, we analyse the changes of the corresponding surface shapes as
the rate of rotation is increased. For a sufficiently weak degree of
differential rotation, the sequences terminate at a mass-shedding limit, while
for moderate and strong rates of differential rotation, they exhibit a
continuous parametric transition to a regime of toroidal fluid bodies. In this
article, we concentrate on the appearance of this transition, analyse in detail
its occurrence and show its relevance for the calculation of astrophysical
sequences. Moreover, we find that the solution space contains various types of
spheroidal configurations, which were not considered in previous work, mainly
due to numerical limitations.


title:
Electrodynamics in a Filled Minkowski Spacetime with Application to
  Classical Continuum Electrodynamics

abstract:
  Minkowski spacetime is a convenient setting for the study of the relativistic
dynamics of particles and fields in the vacuum. In order to study events that
occur in a dielectric or other linear medium, we adopt the familiar continuum
assumption of a linear, isotropic, homogeneous, transparent medium of
refractive index n filling all space and seek the principle of relativity that
applies in the filled spacetime. Applying the Einstein postulates with c/n as
the speed of light, we show how the effective signal velocity results in a
scaling of the proper time by the refractive index and examine the consequences
for D'Alembert's principle, the Lagrange equations, and the canonical momentum
field. The principles of dynamics in the filled spacetime are then applied to
the electromagnetic Lagrangian and we derive equations of motion that are
invariant with respect to a material Lorentz transformation. The new
representation of the dynamics of macroscopic fields is shown to be consistent
with the equal-time commutation relation for quantized macroscopic fields,
quantum--classical correspondence, the principle of superposition, and
electromagnetic boundary conditions.


title: The updated spectral catalogue of INTEGRAL Gamma-Ray Bursts

abstract:
  We present a catalogue with the properties of all the bursts detected and
localized by the IBIS instrument onboard the INTEGRAL satellite from November
2002 to September 2008. The sample is composed of 56 bursts, corresponding to a
rate of ~ 0.8 GRB per month. Thanks to the performances of the INTEGRAL Burst
Alert System, 50% of the IBIS GRBs have detected afterglows, while 5% have
redshift measurements. A spectral analysis of the 43 bursts in the INTEGRAL
public archive has been carried out using the most recent software and
calibration, deriving an updated, homogeneous and accurate catalogue with the
spectral features of the sample. When possible also a time-resolved spectral
analysis has been carried out. The GRBs in the sample have 20-200 keV fluences
in the range 5 x 1E-8 --2.5 x 1E-4 erg cm-2, and peak fluxes in the range 0.11
- 56 ph cm-2 s-1. While most of the spectra are well fitted by a power law with
photon index ~ 1.6, we found that 9 bursts are better described by a cut-off
power law, resulting in Ep values in the range 35--190 keV. Altough these
results are comparable with those obtained with BAT onboard Swift, there is a
marginal evidence that ISGRI detects dimmer bursts than Swift/BAT. Using the
revised spectral parameters and an updated sky exposure map that takes into
account also the effects of the GRB trigger efficiency, we strengthen the
evidence for a spatial correlation with the super galactic plane of the faint
bursts with long spectral lag (Foley et al.,2008).


title: Arakelov (in)equalities

abstract:
  We discuss several numerical conditions for families of projective varieties
or variations of Hodge structures.


title:
Numerical Studies of Quantum Oscillations in the Superconducting vortex
  mixed state

abstract:
  We studied the quantum oscillations in superconducting vortex mixed states
with d-wave pairing. We showed that the Onsager relation does not always apply.
Furthermore, at mean field level the quantum oscillations from electron pockets
are suppressed by the pairing. We conclude that an interpretation of the
experimental results asccoming from the four hole pockets created by a
$(\pi,\pi)$ folding cannot be ruled out.


title:
Probing the membrane potential of living cells by dielectric
  spectroscopy

abstract:
  In this paper we demonstrate a quantitative way to measure the membrane
potential of live cells by dielectric spectroscopy. We also show that the
values of the membrane potential obtained using our technique are in good
agreement with those obtained using traditional methods-voltage sensitive dyes.
The membrane potential is determined by fitting the experimental dielectric
dispersion curves with the dispersion curves obtain from a theoretical model.
Variations in the membrane potential were induced by modifying the
concentration of potassium chloride in the solution of the cell suspension in
the presence of valinomycin. For exemplification of the method, E. coli were
chosen for our experiments.


title:
Minimal volume and simplicial norm of visibility n-manifolds and compact
  3-manifolds

abstract:
  Theorem A. Let $M^n$ denote a closed Riemannian manifold with nonpositive
sectional curvature and let $\tilde M^n$ be the universal cover of $M^n$ with
the lifted metric. Suppose that the universal cover $\tilde M^n$ contains no
totally geodesic embedded Euclidean plane $\mathbb{R}^2$ (i.e., $M^n$ is a
visibility manifold). Then Gromov's simplicial volume $\| M^n \|$ is non-zero.
Consequently, $M^n$ is non-collapsible while keeping Ricci curvature bounded
from below. More precisely, if $Ric_g \ge -(n-1)$, then $vol(M^n, g) \ge
\frac{1}{(n-1)^n n!} \| M^n \| > 0.
  Theorem B. (Perelman) Let $M^3$ be a closed a-spherical 3-manifold ($K(\pi,
1)$-space) with the fundamental group $\Gamma$. Suppose that $\Gamma$ contains
no subgroups isomorphic to $\mathbb{Z}\oplus \mathbb{Z}$. Then $M^3$ is
diffeomorphic to a compact quotient of real hyperbolic space $\mathbb{H}^3$,
i.e., $M^3 \equiv \mathbb{H}^3/\Gamma$. Consequently, $MinVol(M^3) \ge {1/24}\|
M^3 \| > 0$.
  Minimal volume and simplicial norm of all other compact 3-manifolds without
boundary and {\it singular} spaces will also be discussed.


title: Floor decompositions of tropical curves : the planar case

abstract:
  In a previous paper, we announced a formula to compute Gromov-Witten and
Welschinger invariants of some toric varieties, in terms of combinatorial
objects called floor diagrams. We give here detailed proofs in the tropical
geometry framework, in the case when the ambient variety is a complex surface,
and give some examples of computations using floor diagrams. The focusing on
dimension 2 is motivated by the special combinatoric of floor diagrams compared
to arbitrary dimension.
  We treat a general toric surface case in this dimension: the curve is given
by an arbitrary lattice polygon and include computation of Welschinger
invariants with pairs of conjugate points. See also \cite{FM} for combinatorial
treatment of floor diagrams in the projective case.


title: The Dixmier-Moeglin equivalence for twisted homogeneous coordinate rings

abstract:
  Given a projective scheme $X$ over a field $k$, an automorphism $\sigma$ of
$X$, and a $\sigma$-ample invertible sheaf $L$, one may form the twisted
homogeneous coordinate ring $B = B(X, L, \sigma)$, one of the most fundamental
constructions in noncommutative projective algebraic geometry. We study the
primitive spectrum of $B$, as well as that of other closely related algebras
such as skew and skew-Laurent extensions of commutative algebras. Over an
algebraically closed, uncountable field $k$ of characteristic zero, we prove
that that the primitive ideals of $B$ are characterized by the usual
Dixmier-Moeglin conditions whenever the dimension of $X$ is no more than 2.


title: Definite integrals by the method of brackets. Part 1

abstract:
  A new heuristic method for the evaluation of definite integrals is presented.
This method of brackets has its origin in methods developed for theevaluation
of Feynman diagrams. We describe the operational rules and illustrate the
method with several examples. The method of brackets reduces the evaluation of
a large class of definite integrals to the solution of a linear system of
equations.


title: Brief report on `Radiative $\phi$ decays with derivative interactions'

abstract:
  We study the line shapes of radiative $\phi$-decays with a direct coupling of
the $\phi$ meson to the $f_{0}(980)$ and $a_{0}(980)$ scalar mesons. The latter
couple via derivative interactions to $\pi_0 \pi_0$ and $\pi_0 \eta$,
respectively. Although the kaon-loop mechanism is usually regarded as the
dominant mechanism in radiative $\phi$ decays, here we test a different
possibility: we set the kaon-loop to zero and we fit the theoretical curves to
the data by retaining only the direct coupling. Remarkably, satisfactory fits
can be achieved, mainly due to the effects of derivative interactions of scalar
with pseudoscalar mesons.


title:
Study of the Spectral and Temporal Characteristics of X-Ray Emission of
  the Gamma-Ray Binary LS 5039 with Suzaku

abstract:
  We report on the results from Suzaku broadband X-ray observations of the
galactic binary source LS5039. The Suzaku data, which have continuous coverage
of more than one orbital period, show strong modulation of the X-ray emission
at the orbital period of this TeV gamma-ray emitting system.The X-ray emission
shows a minimum at orbital phase ~ 0.1, close to the so-called superior
conjunction of the compact object, and a maximum at phase ~0.7, very close to
the inferior conjunction of the compact object. The X-ray spectral data up to
70 keV are described by a hard power-law with a phase-dependent photon index
which varies within Gamma ~1.45 - 1.61. The amplitude of the flux variation is
a factor of 2.5, but is significantly less than that of the factor ~8 variation
in the TeV flux. Otherwise the two light curves are similar, but not identical.
Although periodic X-ray emission has been found from many galactic binary
systems, the Suzaku result implies a phenomenon different from the "standard"
origin of X-rays related to the emission of the hot accretion plasma formed
around the compact companion object. The X-ray radiation of LS5039is likely to
be linked to very-high-energy electrons which are also responsible for the TeV
gamma-ray emission. While the gamma-rays are the result of inverse Compton
scattering by electrons on optical stellar photons, X-rays are produced via
synchrotron radiation. Yet, while the modulation of the TeV gamma-ray signal
can be naturally explained by the photon-photon pair production and anisotropic
inverse Compton scattering, the observed modulation of synchrotron X-rays
requires an additional process, the most natural one being adiabatic expansion
in the radiation production region.


title: Cumulants and the moment algebra: tools for analysing weak measurements

abstract:
  Recently it has been shown that cumulants significantly simplify the analysis
of multipartite weak measurements. Here we consider the mathematical structure
that underlies this, and find that it can be formulated in terms of what we
call the moment algebra. Apart from resulting in simpler proofs, the
flexibility of this structure allows generalizations of the original results to
a number of weak measurement scenarios, including one where the weakly
interacting pointers reach thermal equilibrium with the probed system.


title:
Eta meson rescattering effects in the p + 6Li --> eta + 7Be reaction
  near threshold

abstract:
  The p + 6Li --> eta + 7Be reaction has been investigated with an emphasis on
the eta meson and 7Be interaction in the final state. Considering the 6Li and
7Be nuclei to be alpha-d and alpha-3He clusters respectively, the reaction is
modelled to proceed via the p + d [alpha] --> 3He [\alpha] + eta reaction with
the alpha remaining a spectator. The eta meson interacts with 7Be via multiple
scatterings on the 3He and alpha clusters inside 7Be. The individual eta-3He
and eta-alpha scatterings are evaluated using few body equations for the eta-3N
and eta-4N systems with a coupled channel eta-N interaction as an input.
Calculations including four low-lying states of 7Be lead to a double hump
structure in the total cross section corresponding to the $L = 1 (J = (1/2)^-,
(3/2)^-)$ and $L = 3 (J = (5/2)^-, (7/2)^-)$ angular momentum states. The humps
arise due to the off-shell rescattering of the eta meson on the 7Be nucleus in
the final state.


title:
Correcting the polarization effect in low frequency Dielectric
  Spectroscopy

abstract:
  We demonstrate a simple and robust methodology for measuring and analyzing
the polarization impedance appearing at interface between electrodes and ionic
solutions, in the frequency range from 1 to $10^6$ Hz. The method assumes no
particular behavior of the electrode polarization impedance and it only makes
use of the fact that the polarization effect dies out with frequency. The
method allows a direct and un-biased measurement of the polarization impedance,
whose behavior with the applied voltages and ionic concentration is
methodically investigated. Furthermore, based on the previous findings, we
propose a protocol for correcting the polarization effect in low frequency
Dielectric Spectroscopy measurements of colloids. This could potentially lead
to the quantitative resolution of the $\alpha$-dispersion regime of live cells
in suspension.


title: Microscopic entropy of black holes and AdS_2 quantum gravity

abstract:
  Quantum gravity (QG) on two-dimensional anti-de Sitter spacetime (AdS_2)
takes always the form of a chiral conformal field theory (CFT). However, the
actual content of the CFT, and in particular its central charge, depends on the
background values of the dilaton and Maxwell field. We review the main features
of AdS_2 QG with linear dilaton and of AdS_2 QG with constant dilaton and
Maxwell field. We also show that the 3D charged Banados-Teitelboim-Zanelli
black hole interpolates between these two versions of AdS_2 QG. Applications to
the computation of the microscopic entropy of black holes are also discussed.


title:
Mathematical Tools for Calculation of the Effective Action in Quantum
  Gravity

abstract:
  We review the status of covariant methods in quantum field theory and quantum
gravity, in particular, some recent progress in the calculation of the
effective action via the heat kernel method. We study the heat kernel
associated with an elliptic second-order partial differential operator of
Laplace type acting on smooth sections of a vector bundle over a Riemannian
manifold without boundary. We develop a manifestly covariant method for
computation of the heat kernel asymptotic expansion as well as new algebraic
methods for calculation of the heat kernel for covariantly constant background,
in particular, on homogeneous bundles over symmetric spaces, which enables one
to compute the low-energy non-perturbative effective action.


title: Weyl Invariance and the Origins of Mass

abstract:
  By a uniform and simple Weyl invariant coupling of scale and matter fields,
we construct theories that unify massless, massive, and partially massless
excitations. Masses are related to tractor Weyl weights, and
Breitenlohner-Freedman stability bounds in anti de Sitter amount to reality of
these weights. The method relies on tractor calculus -- mathematical machinery
allowing Weyl invariance to be kept manifest at all stages. The equivalence
between tractor and higher spin systems with arbitrary spins and masses is also
considered.


title: Twisted modules for quantum vertex algebras

abstract:
  We study twisted modules for (weak) quantum vertex algebras and we give a
conceptual construction of (weak) quantum vertex algebras and their twisted
modules. As an application we construct and classify irreducible twisted
modules for a certain family of quantum vertex algebras.


title: Coreless Vortices in Rotating Two-Component Quantum Droplets

abstract:
  The rotation of a quantum liquid induces vortices to carry angular momentum.
When the system is composed of multiple components that are distinguishable
from each other, vortex cores in one component may be filled by particles of
the other component, and coreless vortices form. Based on evidence from
computational methods, here we show that the formation of coreless vortices
occurs very similarly for repulsively interacting bosons and fermions, largely
independent of the form of the particle interactions. We further address the
connection to the Halperin wave functions of non-polarized quantum Hall states.


title: Scattering in Mass-Deformed N>=4 Chern-Simons Models

abstract:
  We investigate the scattering matrix in mass-deformed N>=4 Chern-Simons
models including as special cases the BLG and ABJM theories of multiple M2
branes. Curiously the structure of this scattering matrix in three spacetime
dimensions is equivalent to (a) the two-dimensional worldsheet matrix found in
the context of AdS/CFT integrability and (b) the R-matrix of the
one-dimensional Hubbard model. The underlying reason is that all three models
are based on an extension of the psu(2|2) superalgebra which constrains the
matrix completely. We also compute scattering amplitudes in one-loop field
theory and find perfect agreement with scattering unitarity.


title:
An explanation of the $\Delta_{5/2^{-}}(1930)$ as a $\rho\Delta$ bound
  state

abstract:
  We use the $\rho\Delta$ interaction in the hidden gauge formalism to
dynamically generate $N^{\ast}$ and $\Delta^{\ast}$ resonances. We show,
through a comparison of the results from this analysis and from a quark model
study with data, that the $\Delta_{5/2^{-}}(1930),$ $\Delta_{3/2^{-}}(1940)$
and $\Delta_{1/2^{-}}(1900)$ resonances can be assigned to $\rho\Delta$ bound
states. More precisely the $\Delta_{5/2^{-}}(1930)$ can be interpreted as a
$\rho\Delta$ bound state whereas the $\Delta_{3/2^{-}}(1940)$ and
$\Delta_{1/2^{-}}(1900)$ may contain an important $\rho\Delta$ component. This
interpretation allows for a solution of a long-standing puzzle concerning the
description of these resonances in constituent quark models. In addition we
also obtain degenerate $J^{P}=1/2^{-},3/2^{-},5/2^{-}$ $N^{*}$ states but their
assignment to experimental resonances is more uncertain.


title: On the singular scheme of codimension one holomorphic foliations in P^3

abstract:
  In this work, we begin by showing that a holomorphic foliation with
singularities is reduced if and only if its normal sheaf is torsion free. In
addition, when the codimension of the singular locus is at least two, it is
shown that being reduced is equivalent to the reflexivity of the tangent sheaf.
Our main results state on one hand, that the tangent sheaf of a codimension one
foliation in P^3 is locally free if and only the singular scheme is a curve,
and that it splits if and only if that curve is arithmetically Cohen-Macaulay.
On the other hand, we discuss when a split foliation in P^3 is determined by
its singular scheme.


title: Nuclear Parton Distribution Functions

abstract:
  We study nuclear effects of charged current deep inelastic neutrino-iron
scattering in the framework of a chi^2 analysis of parton distribution
functions (PDFs). We extract a set of iron PDFs which are used to compute
x_Bj-dependent and Q^2-dependent nuclear correction factors for iron structure
functions which are required in global analyses of free nucleon PDFs. We
compare our results with nuclear correction factors from neutrino-nucleus
scattering models and correction factors for charged-lepton--iron scattering.
We find that, except for very high x_Bj, our correction factors differ in both
shape and magnitude from the correction factors of the models and
charged-lepton scattering.


title: Heavy Quarks: Lessons Learned from HERA and Tevatron

abstract:
  We review some of the recent developments which have enabled the heavy quark
mass to be incorporated into both the calculation of the hard-scattering cross
section and the PDFs. We compare and contrast some of the schemes that have
been used in recent global PDF analyses, and look at issues that arise when
these calculations are extended to NNLO.


title: Tracing the asymmetry in the envelope around the carbon star CIT 6

abstract:
  We present high angular resolution observations of HC$_3$N J=5--4 line and 7
mm continumm emission from the extreme carbon star CIT 6. We find that the 7 mm
continuum emission is unresolved and has a flux consistent with black-body
thermal radiation from the central star. The HC$_3$N J=5--4 line emission
originates from an asymmetric and clumpy expanding envelope comprising two
separate shells of HC$_3$N J=5--4 emission: (i) a faint outer shell that is
nearly spherical which has a radius of 8\arcsec; and (ii) a thick and
incomplete inner shell that resembles a one-arm spiral starting at or close to
the central star and extending out to a radius of about 5\arcsec. Our
observations therefore suggest that the mass loss from CIT 6 is strongly
modulated with time and highly anisotropic. Furthermore, a comparison between
the data and our excitation modelling results suggests an unusually high
abundance of HC$_3$N in its envelope. We discuss the possibility that the
envelope might be shaped by the presence of a previously suggested possible
binary companion. The abundance of HC$_3$N may be enhanced in spiral shocks
produced by the interaction between the circumstellar envelope of CIT 6 and its
companion star.


title:
Flux compactifications and supersymmetry breaking in 6D gauged
  supergravity

abstract:
  We review on a recent construction of the on-shell supersymmetric brane
action for the codimension-two branes with nonzero tension in the flux
compactification of a 6D chiral gauged supergravity. On dimesionally reducing
on 4D gauged supergravity for a new supersymmetric unwarped background with
conical branes, we consider the modulus stabilization for determining the soft
masses of the scalars localized on the branes and show that the bulk U(1)_R
provides a new mechanism for mediating the SUSY breaking.


title: A remarkable sequence of integers

abstract:
  A survey of properties of a sequence of coefficients appearing in the
evaluation of a quartic definite integral is presented. These properties are of
analytical, combinatorial and number-theoretical nature.


title: The shaping effect of collimated fast outflows in the Egg nebula

abstract:
  We present high angular resolution observations of the HC$_3$N J=5--4 line
from the Egg nebula, which is the archetype of protoplanetary nebulae. We find
that the HC$_{\rm 3}$N emission in the approaching and receding portion of the
envelope traces a clumpy hollow shell, similar to that seen in normal carbon
rich envelopes. Near the systemic velocity, the hollow shell is fragmented into
several large blobs or arcs with missing portions correspond spatially to
locations of previously reported high--velocity outlows in the Egg nebula. This
provides direct evidence for the disruption of the slowly--expanding envelope
ejected during the AGB phase by the collimated fast outflows initiated during
the transition to the protoplanetary nebula phase. We also find that the
intersection of fast molecular outflows previously suggested as the location of
the central post-AGB star is significantly offset from the center of the hollow
shell. From modelling the HC$_3$N distribution we could reproduce qualitatively
the spatial kinematics of the HC$_3$N J=5--4 emission using a HC$_3$N shell
with two pairs of cavities cleared by the collimated high velocity outflows
along the polar direction and in the equatorial plane. We infer a relatively
high abundance of HC$_3$N/H$_2$ $\sim$3x10$^{-6}$ for an estimated mass--loss
rate of 3x10$^{-5}$ M$_\odot$ yr$^{-1}$ in the HC$_3$N shell. The high
abundance of HC$_3$N and the presence of some weaker J=5--4 emission in the
vicinity of the central post-AGB star suggest an unusually efficient formation
of this molecule in the Egg nebula.


title:
Open charm production at high energies and the quark Reggeization
  hypothesis

abstract:
  We study open charm production at high energies in the framework of the
quasi-multi-Regge-kinematics approach applying the quark-Reggeization
hypothesis implemented with Reggeon-Reggeon-particle and
Reggeon-particle-particle effective vertices. Adopting the Kimber-Martin-Ryskin
unintegrated quark and gluon distribution functions of the proton and photon,
we thus nicely describe the proton structure function F_{2,c} measured at DESY
HERA as well as the transverse-momentum distributions of D mesons created by
photoproduction at HERA and by hadroproduction at the Fermilab Tevatron.


title: Dynamical dark energy and variation of fundamental "constants"

abstract:
  In this thesis we study the influence of a possible variation of fundamental
"constants" on the process of Big Bang Nucleosynthesis (BBN). Our findings are
combined with further studies on variations of constants in other physical
processes to constrain models of grand unification (GUT) and quintessence. We
will find that the 7Li problem of BBN can be ameliorated if one allows for
varying constants, where especially varying light quark masses show a strong
influence. Furthermore, we show that recent studies of varying constants are in
contradiction with each other and BBN in the framework of six exemplary GUT
scenarios, if one assumes monotonic variation with time. We conclude that there
is strong tension between recent claims of varying constants, hence either some
claims have to be revised, or there are much more sophisticated GUT relations
(and/or non-monotonic variations) realized in nature. The methods introduced in
this thesis prove to be powerful tools to probe regimes well beyond the
Standard Model of particle physics or the concordance model of cosmology, which
are currently inaccessible by experiments. Once the first irrefutable proofs of
varying constants are available, our method will allow for probing the
consistency of models beyond the standard theories like GUT or quintessence and
also the compatibility between these models.


title:
On the Financial Crisis 2008 from a Physicist's viewpoint: A Spin-Glass
  Interpretation

abstract:
  In an informal way, a number of thoughts on the financial crisis 2008 are
presented from a physicist's viewpoint, considering the problem as a
nonergodicity transition of a spin-glass type of system. Some tentative
suggestions concerning the way out of the crisis are also discussed, concerning
Keynesian "deficit spending" methods, tax reductions, and finally the method
"ruin and recreate" known from optimization theory. Also the de
Almeida-Thouless instability line of spin-glass theory is given a financial
interpretation.


title: Hartogs' extension theorems on Stein spaces

abstract:
  We discuss various known generalizations of the classical Hartogs' extension
theorem on Stein spaces with arbitrary singularities and present an analytic
proof based on d-bar methods.


title:
Electric field noise above surfaces: a model for heating rate scaling
  law in ion traps

abstract:
  We present a model for the scaling laws of the electric field noise spectral
density as a function of the distance, $d$, above a conducting surface. Our
analytical approach models the patch potentials by introducing a correlation
length, $\zeta$, of the electric potential on the surface. The predicted
scaling laws are in excellent agreement with two different classes of
experiments (cold trapped ions and cantilevers), that span at least four orders
of magnitude of $d$. According to this model, heating rate in miniature ion
traps could be greatly reduced by proper material engineering.


title:
Computation of VaR and CVaR using stochastic approximations and
  unconstrained importance sampling

abstract:
  Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR) are two risk
measures which are widely used in the practice of risk management. This paper
deals with the problem of computing both VaR and CVaR using stochastic
approximation (with decreasing steps): we propose a first Robbins-Monro
procedure based on Rockaffelar-Uryasev's identity for the CVaR. The convergence
rate of this algorithm to its target satisfies a Gaussian Central Limit
Theorem. As a second step, in order to speed up the initial procedure, we
propose a recursive importance sampling (I.S.) procedure which induces a
significant variance reduction of both VaR and CVaR procedures. This idea,
which goes back to the seminal paper of B. Arouna, follows a new approach
introduced by V. Lemaire and G. Pag\`es. Finally, we consider a deterministic
moving risk level to speed up the initialization phase of the algorithm. We
prove that the convergence rate of the resulting procedure is ruled by a
Central Limit Theorem with minimal variance and its efficiency is illustrated
by considering several typical energy portfolios.


title: p-Density, exponential sums and Artin-Schreier curves

abstract:
  In this paper we define the $p$-density of a finite subset
$D\subset\ma{N}^r$, and show that it gives a good lower bound for the $p$-adic
valuation of exponential sums over finite fields of characteristic $p$. We also
give an application: when $r=1$, the $p$-density is the first slope of the
generic Newton polygon of the family of Artin-Schreier curves associated to
polynomials with their exponents in $D$.


title:
Experimental observation of strong light-matter coupling in ZnO
  microcavities: influence of large excitonic absorption

abstract:
  We present experimental observation of the strong light-matter coupling
regime in ZnO bulk microcavities grown on silicon. Angle resolved reflectivity
measurements, corroborated by transfer-matrix simulations, show that Rabi
splittings in the order of 70 meV are achieved even for low finesse cavities.
The impact of the large excitonic absorption, which enables a ZnO bulk-like
behavior to be observed even in the strong coupling regime, is illustrated both
experimentally and theoretically by considering cavities with increasing
thickness.


title:
Chloroplast microsatellites reveal colonization and metapopulation
  dynamics in the Canary Island pine

abstract:
  Chloroplast microsatellites are becoming increasingly popular markers for
population genetic studies in plants, but there has been little focus on their
potential for demographic inference. In this work the utility of chloroplast
microsatellites for the study of population expansions was explored. First, we
investigated the power of mismatch distribution analysis and the F(S) test with
coalescent simulations of different demographic scenarios. We then applied
these methods to empirical data obtained for the Canary Island pine (Pinus
canariensis). The results of the simulations showed that chloroplast
microsatellites are sensitive to sudden population growth. The power of the
F(S) test and accuracy of demographic parameter estimates, such as the time of
expansion, were reduced proportionally to the level of homoplasy within the
data. The analysis of Canary Island pine chloroplast microsatellite data
indicated population expansions for almost all sample localities. Demographic
expansions at the island level can be explained by the colonization of the
archipelago by the pine, while population expansions of different ages in
different localities within an island could be the result of local extinctions
and recolonization dynamics. Comparable mitochondrial DNA sequence data from a
parasite of P. canariensis, the weevil Brachyderes rugatus, supports this
scenario, suggesting a key role for volcanism in the evolution of pine forest
communities in the Canary Islands.


title:
Global Behavior of Solutions to Two Classes of Second Order Rational
  Difference Equations

abstract:
  For nonnegative real numbers $\alpha$, $\beta$, $\gamma$, $A$, $B$ and $C$
such that $B+C>0$ and $\alpha+\beta+\gamma >0$, the difference equation
  \begin{equation*} x_{n+1}=\displaystyle\frac{\alpha +\beta x_{n}+\gamma
x_{n-1}}{A+B x_{n}+C x_{n-1}}, \quad n=0,1,2,... %, \quad x_{-1},x_{0}\in
[0,\infty) \end{equation*} has a unique positive equilibrium. A proof is given
here for the following statements: \medskip
  \noindent Theorem 1. {\it For every choice of positive parameters $\alpha$,
$\beta$, $\gamma$, $A$, $B$ and $C$, all solutions to the difference equation
  \begin{equation*} x_{n+1}=\displaystyle\frac{\alpha +\beta x_{n}+\gamma
x_{n-1}}{A+B x_{n}+C x_{n-1}}, \quad n=0,1,2,..., \quad x_{-1},x_{0}\in
[0,\infty) \end{equation*} converge to the positive equilibrium or to a prime
period-two solution.} \medskip
  \noindent Theorem 2. {\it For every choice of positive parameters $\alpha$,
$\beta$, $\gamma$, $A$, $B$ and $C$, all solutions to the difference equation
\begin{equation*} x_{n+1}= \displaystyle\frac{\alpha +\beta x_{n}+\gamma
x_{n-1}}{B x_{n}+C x_{n-1}}, \quad n=0,1,2,..., \quad x_{-1},x_{0}\in
(0,\infty) \end{equation*} converge to the positive equilibrium or to a prime
period-two solution.}


title: Two pairs of interacting EBs towards the LMC in the OGLE database

abstract:
  A single point source on the OGLE LMC database shows the characteristics of
two superimposed eclipsing binaries (EBs). The two EBs happen to have periods
very close to the 3:2 resonance. The telescope's small PSF and the apparent
resonance between the two EBs raises the suspicion that this is not chance
alignment but rather a compact hierarchical system of two pairs of interacting
EBs in 3:2 resonance.


title: Observable Bulk Signatures of Non-Abelian Quantum Hall States

abstract:
  We show that non-abelian quantum Hall states can be identified by
experimental measurements of the temperature-dependence of either the
electrochemical potential or the orbital magnetization. The predicted signals
of non-abelian statistics are within experimental resolution, and can be
clearly distinguished from other contributions under realistic circumstances.
The proposed measurement technique also has the potential to resolve
spin-ordering transitions in low density electronic systems in the Wigner
crystal and strongly-interacting Luttinger liquid regimes.


title: Dark Energy and the Return of the Phoenix Universe

abstract:
  In cyclic universe models based on a single scalar field (e.g., the radion
determining the distance between branes in M-theory), virtually the entire
universe makes it through the ekpyrotic smoothing and flattening phase,
bounces, and enters a new epoch of expansion and cooling. This stable evolution
cannot occur, however, if scale-invariant curvature perturbations are produced
by the entropic mechanism because it requires two scalar fields (e.g., the
radion and the Calabi-Yau dilaton) evolving along an unstable classical
trajectory. In fact, we show here that an overwhelming fraction of the universe
fails to make it through the ekpyrotic phase; nevertheless, a sufficient volume
survives and cycling continues forever provided the dark energy phase of the
cycle lasts long enough, of order a trillion years. Two consequences are a new
role for dark energy and a global structure of the universe radically different
from that of eternal inflation.


title: Contact deformations of closed 1-forms on Torus bundles over the circle

abstract:
  If a closed 3-manifold M supports a closed, nonsingular, irrational 1-form
which linearly deforms into contact forms, then M supports a K-contact form. On
the 3-torus, a closed nonsingular 1-form deforms linearly into contact forms if
and only if it is a fibration 1-form. on any other 2-torus bundle over the
circle, every closed, nonsingular 1-form deforms linearly into contact forms.


title: Dense sphere packings from optimized correlation functions

abstract:
  Elementary smooth functions (beyond contact) are employed to construct pair
correlation functions that mimic jammed disordered sphere packings. Using the
g2-invariant optimization method of Torquato and Stillinger [J. Phys. Chem. B
106, 8354, 2002], parameters in these functions are optimized under necessary
realizability conditions to maximize the packing fraction phi and average
number of contacts per sphere Z. A pair correlation function that incorporates
the salient features of a disordered packing and that is smooth beyond contact
is shown to permit a phi of 0.6850: this value represents a 45% reduction in
the difference between the maximum for congruent hard spheres in three
dimensions, pi/sqrt{18} ~ 0.7405, and 0.64, the approximate fraction associated
with maximally random jammed (MRJ) packings in three dimensions. We show that,
surprisingly, the continued addition of elementary functions consisting of
smooth sinusoids decaying as r^{-4} permits packing fractions approaching
pi/sqrt{18}. A translational order metric is used to discriminate between
degrees of order in the packings presented. We find that to achieve higher
packing fractions, the degree of order must increase, which is consistent with
the results of a previous study [Torquato et al., Phys. Rev. Lett. 84, 2064,
2000].


title:
Double-Scaling Limit of Heterotic Bundles and Dynamical Deformation in
  CFT

abstract:
  We consider heterotic string theory on Eguchi-Hanson space, as a local model
of a resolved A_1 singularity in a six-dimensional flux compactification, with
an Abelian gauge bundle turned on and non-zero torsion. We show that in a
suitable double scaling limit, that isolates the physics near the non-vanishing
two-cycle, a worldsheet conformal field theory description can be found. It
contains a heterotic coset whose target space is conformal to Eguchi-Hanson.
Starting from the blow-down limit of the singularity, it can be viewed as a
dynamical deformation of the near-horizon fivebrane background. We analyze in
detail the spectrum of the theory in particular examples, as well as the
important role of worldsheet non-perturbative effects.


title: Probing ISM Magnetic Fields With SNRs

abstract:
  As supernova remnants expand, their shock waves are freezing in and
compressing the magnetic field lines they encounter; consequently we can use
supernova remnants as magnifying glasses for their ambient magnetic fields. We
will describe a simple model to determine emission, polarization, and rotation
measure characteristics of adiabatically expanding supernova remnants and how
we can exploit this model to gain information about the large scale magnetic
field in our Galaxy. We will give two examples: The SNR DA530, which is located
high above the Galactic plane, reveals information about the magnetic field in
the halo of our Galaxy. The SNR G182.4+4.3 is located close to the anti-centre
of our Galaxy and reveals the most probable direction where the large-scale
magnetic field is perpendicular to the line of sight. This may help to decide
on the large-scale magnetic field configuration of our Galaxy.


title:
Free-streaming approximation in early dynamics of relativistic heavy-ion
  collisions

abstract:
  We investigate an approximation to early dynamics in relativistic heavy-ion
collisions, where after formation the partons are free streaming and around the
proper time of 1 fm/c undergo a sudden equilibration described in terms of the
Landau matching condition. We discuss physical and formal aspects of this
approach. In particular, we show that initial azimuthally asymmetric transverse
flow develops for non-central collisions as a consequence of the sudden
equilibration. Moreover, the energy-momentum tensor from the free-streaming
stage matches very smoothly to the form used in the transverse hydrodynamics,
whereas matching to isotropic hydrodynamics requires a more pronounced change
in the energy-momentum tensor. After the hydrodynamic phase statistical
hadronization is carried out with the help of THERMINATOR. The physical results
for the transverse-momentum spectra, the elliptic-flow, and the
Hanbury-Brown--Twiss correlation radii, including the ratio R_out/R_side as
well as the dependence of the radii on the azimuthal angle (azHBT), are
properly described within our approach. The agreement is equally good for a
purely hydrodynamic evolution started at an early proper time of 0.25 fm/c, or
for the free streaming started at that time, followed by the sudden
equilibration at tau ~1 fm/c and then by perfect hydrodynamics. Thus, the
inclusion of free streaming allows us to delay the start of hydrodynamics to
more realistic times of the order of 1 fm/c.


title:
Pressure-induced magnetic transition and volume collapse in FeAs
  superconductors: An orbital-selective Mott scenario

abstract:
  Motivated by pressure experiments on FeAs-122 superconductors, we propose a
scenario based on local-moment physics to explain the simultaneous
disappearance of magnetism, reduction of the unit cell volume, and decrease in
resistivity. In this scenario, the low-pressure magnetic phase derives from Fe
moments, which become screened in the paramagnetic high-pressure phase. The
quantum phase transition can be described as an orbital-selective Mott
transition, which is rendered first order by coupling to the lattice, in
analogy to a Kondo volume collapse. Spin-fluctuation driven superconductivity
competes with antiferromagnetism and may be stabilized at low temperatures in
the high-pressure phase. The ideas are illustrated by a suitable mean-field
analysis of an Anderson lattice model.


title:
A New Secular Instability of Eccentric Stellar Disks Around Supermassive
  Black Holes, with Application to the Galactic Center

abstract:
  We identify a new secular instability of eccentric stellar disks around
supermassive black holes. We show that retrograde precession of the stellar
orbits, due to the presence of a stellar cusp, induces coherent torques that
amplify deviations of individual orbital eccentricities from the average, and
thus drive all eccentricities away from their initial value. We investigate the
instability using N-body simulations, and show that it can drive individual
orbital eccentricities to significantly higher or lower values on the order of
a precession time-scale. This physics is relevant for the Galactic center,
where massive stars are likely to form in eccentric disks around the SgrA*
black hole. We show that the observed bimodal eccentricity distribution of disk
stars in the Galactic center is in good agreement with the distribution
resulting from the eccentricity instability and demonstrate how the dynamical
evolution of such a disk results in several of its stars acquiring high (1-e <
0.1) orbital eccentricity. Binary stars on such highly eccentric orbits would
get tidally disrupted by the SgrA* black hole, possibly producing both S-stars
near the black hole and high-velocity stars in the Galactic halo.


title: Hawking radiation of unparticles

abstract:
  Unparticle degrees of freedom, no matter how weakly coupled to the standard
model particles, must affect the evolution of a black hole, which thermally
decays into all available degrees of freedom. We develop a method for
calculating the grey-body factors for scalar unparticles for 3+1 and higher
dimensional black holes. We find that the power emitted in unparticles may be
quite different from the power emitted in ordinary particles. Depending on the
parameters in the model, unparticles may become the dominant channel. This is
of special interest for small primordial black holes and also in models with
low scale quantum gravity where the experimental signature may significantly be
affected. We also discuss the sensitivity of the results on the (currently
unknown) unparticle normalization.


title: Moduli Webs and Superpotentials for Five-Branes

abstract:
  We investigate the one-parameter Calabi-Yau models and identify families of
D5-branes which are associated to lines embedded in these manifolds. The moduli
spaces are given by sets of Riemann curves, which form a web whose intersection
points are described by permutation branes. We arrive at a geometric
interpretation for bulk-boundary correlators as holomorphic differentials on
the moduli space and use this to compute effective open-closed superpotentials
to all orders in the open string couplings. The fixed points of D5-brane moduli
under bulk deformations are determined.


title:
Global Attractivity of the Equilibrium of a Difference Equation: An
  Elementary Proof Assisted by Computer Algebra System

abstract:
  Let $p$ and $q$ be arbitrary positive numbers. It is shown that if $q < p$,
then all solutions to the difference equation \tag{E} x_{n+1} = \frac{p+q
x_n}{1+x_{n-1}}, \quad n=0,1,2,..., \quad x_{-1}>0, x_0>0 converge to the
positive equilibrium $\overline{x} = {1/2}(q-1 + \sqrt{(q-1)^2 + 4 p})$.
\medskip
  The above result, taken together with the 1993 result of Koci\'c and Ladas
for equation (E) with $q \geq p$, gives global attractivity of the positive
equilibrium of (E) for all positive values of the parameters, thus completing
the proof of a conjecture of Ladas.


title: The Klebanov-Strassler model with massive dynamical flavors

abstract:
  We present a fully backreacted D3-D7 supergravity solution dual to the
Klebanov-Strassler cascading gauge theory coupled to a large number of massive
dynamical flavors in the Veneziano limit. The mass of the flavors can be larger
or smaller than the dynamically generated scale. The solution is always regular
at the origin of the radial coordinate and as such it can be suitably employed
to explore the rich IR physics of the dual gauge theory. In this paper we focus
on the static quark-antiquark potential, the screening of chromoelectric
charges induced by the dynamical flavors, the flux tube breaking and the mass
spectrum of the first mesonic excitations. Moreover, we discuss the occurrence
of quantum phase transitions in the connected part of the static
quark-antiquark potential. Depending on the ratio of certain parameters, like
the flavor mass, with respect to some critical values, we find a discontinuous
(first order) or smooth transition from a Coulomb-like to a linear phase. We
evaluate the related critical exponents finding that they take classical
mean-field values and argue that this is a universal feature of analogous first
order transitions occurring in the static potential for planar gauge theories
having a dual supergravity description.


title:
Search for top-quark production via flavor-changing neutral currents in
  W+1 jet events at CDF

abstract:
  We report on the first search for top-quark production via flavor-changing
neutral-current (FCNC) interactions in the non-standard-model process u(c)+g ->
t using ppbar collision data collected by the CDF II detector. The data set
corresponds to an integrated luminosity of 2.2/fb. The candidate events feature
the signature of semileptonic top-quark decays and are classified as
signal-like or background-like by an artificial neural network trained on
simulated events. The observed discriminant distribution is in good agreement
with the one predicted by the standard model and provides no evidence for FCNC
top-quark production, resulting in a Bayesian upper limit on the production
cross section sigma (u(c)+g -> t) < 1.8 pb at the 95% confidence level. Using
theoretical predictions we convert the cross-section limit to upper limits on
FCNC branching ratios: BR (t -> u+g) < 3.9 x 10{-4}$ and BR (t -> c+g) < 5.7 x
10^{-3}.


title: The X-ray Jets of Active Galaxies

abstract:
  Jet physics is again flourishing as a result of Chandra's ability to resolve
high-energy emission from the radio-emitting structures of active galaxies and
separate it from the X-ray-emitting thermal environments of the jets. These
enhanced capabilities have coincided with an increasing interest in the link
between the growth of super-massive black holes and galaxies, and an
appreciation of the likely importance of jets in feedback processes. I review
the progress that has been made using Chandra and XMM-Newton observations of
jets and the medium in which they propagate, addressing several important
questions, including: Are the radio structures in a state of minimum energy? Do
powerful large-scale jets have fast spinal speeds? What keeps jets collimated?
Where and how does particle acceleration occur? What is jet plasma made of?
What does X-ray emission tell us about the dynamics and energetics of radio
plasma/gas interactions? Is a jet's fate determined by the central engine?


title:
The Environments of Active Galactic Nuclei within the zCOSMOS Density
  Field

abstract:
  The impact of environment on AGN activity up to z~1 is assessed by utilizing
a mass-selected sample of galaxies from the 10k catalog of the zCOSMOS
spectroscopic redshift survey. We identify 147 AGN by their X-ray emission as
detected by XMM-Newton from a parent sample of 7234 galaxies. We measure the
fraction of galaxies with stellar mass M_*>2.5x10^10 Msun that host an AGN as a
function of local overdensity using the 5th, 10th and 20th nearest neighbors
that cover a range of physical scales (~1-4 Mpc). Overall, we find that AGNs
prefer to reside in environments equivalent to massive galaxies with
substantial levels of star formation. Specifically, AGNs with host masses
between 0.25-1x10^11 Msun span the full range of environments (i.e.,
field-to-group) exhibited by galaxies of the same mass and rest-frame color or
specific star formation rate. Host galaxies having M_*>10^11 Msun clearly
illustrate the association with star formation since they are predominantly
bluer than the underlying galaxy population and exhibit a preference for lower
density regions analogous to SDSS studies of narrow-line AGN. To probe the
environment on smaller physical scales, we determine the fraction of galaxies
(M_*>2.5x10^10 Msun) hosting AGNs inside optically-selected groups, and find no
significant difference with field galaxies. We interpret our results as
evidence that AGN activity requires a sufficient fuel supply; the probability
of a massive galaxy to have retained some sufficient amount of gas, as evidence
by its ongoing star formation, is higher in underdense regions where disruptive
processes (i.e., galaxy harrassment, tidal stripping) are lessened.


title:
A geometrical approach to the dynamics of spinor condensates I:
  Hydrodynamics

abstract:
  In this work, we derive the equations of motion governing the hydrodynamics
of spin-F spinor condensates. We pursue a description based on standard
physical variables (total density and superfluid velocity), alongside 2F
`spin-nodes': unit vectors that describe the spin F state, and also exhibit the
point-group symmetry of a spinor condensate's mean-field ground state. The
hydrodynamic equations of motion consist of a mass continuity equation, 2F
Landau-Lifshitz equations for the spin-nodes, and a modified Euler equation. In
particular, we provide a generalization of the Mermin-Ho relation to spin one,
and find an analytic solution for the skyrmion texture in the incompressible
regime of a spin-half condensate. These results exhibit a beautiful geometrical
structure that underlies the dynamics of spinor condensates.


title: Diversity-Multiplexing Tradeoff for the MIMO Static Half-Duplex Relay

abstract:
  In this work, we investigate the diversity-multiplexing tradeoff (DMT) of the
multiple-antenna (MIMO) static half-duplex relay channel. A general expression
is derived for the DMT upper bound, which can be achieved by a
compress-and-forward protocol at the relay, under certain assumptions. The DMT
expression is given as the solution of a minimization problem in general, and
an explicit expression is found when the relay channel is symmetric in terms of
number of antennas, i.e. the source and the destination have n antennas each,
and the relay has m antennas. It is observed that the static half-duplex DMT
matches the full-duplex DMT when the relay has a single antenna, and is
strictly below the full-duplex DMT when the relay has multiple antennas.
Besides, the derivation of the upper bound involves a new asymptotic study of
spherical integrals (that is, integrals with respect to the Haar measure on the
unitary group U(n)), which is a topic of mathematical interest in itself.


title: Connecting Reionization to the Local Universe

abstract:
  We present results of combined N-body and three-dimensional reionization
calculations to determine the relationship between reionization history and
local environment in a volume 1 Gpc/h across and a resolution of about 1 Mpc.
We resolve the formation of about 2x10^6 halos of mass greater than ~10^12 Msun
at z=0, allowing us to determine the relationship between halo mass and
reionization epoch for galaxies and clusters. For our fiducial reionization
model, in which reionization begins at z~15 and ends by z~6, we find a strong
bias for cluster-size halos to be in the regions which reionized first, at
redshifts 10<z<15. Consequently, material in clusters was reionized within
relatively small regions, on the order of a few Mpc, implying that all clusters
in our calculation were reionized by their own progenitors. Milky Way mass
halos were on average reionized later and by larger regions, with a
distribution similar to the global one, indicating that low mass halos are
relatively uncorrelated with reionization when only their mass is taken as a
prior. On average, we find that most halos with mass less than 10^13 Msun were
reionized internally, while almost all halos with masses greater than 10^14
Msun were reionized by their own progenitors. We briefly discuss the
implications of this work in light of the "missing satellites" problem and how
this new approach may be extended further.


title: Technicolor Dark Matter

abstract:
  Dark Matter candidates are natural in Technicolor theories. We introduce a
general framework allowing to predict signals of Technicolor Dark Matter at
colliders and set constraints from earth based experiments such as CDMS and
XENON. We show that the associate production of the composite Higgs can lead to
relevant signals at the Large Hadron Collider.


title: Hopf Algebras of Graphs

abstract:
  We define graded Hopf algebras with bases labeled by various types of graphs
and hypergraphs, provided with natural embeddings into an algebra of
polynomials in infinitely many variables. These algebras are graded by the
number of edges and can be considered as generalizations of symmetric or
quasi-symmetric functions.


title: $d$-Koszul algebras, 2-$d$ determined algebras and 2-$d$-Koszul algebras

abstract:
  The relationship between an algebra and its associated monomial algebra is
investigated when at least one of the algebras is $d$-Koszul. It is shown that
an algebra which has a reduced \grb basis that is composed of homogeneous
elements of degree $d$ is $d$-Koszul if and only if its associated monomial
algebra is $d$-Koszul. The class of 2-$d$-determined algebras and the class
2-$d$-Koszul algebras are introduced. In particular, it shown that
2-$d$-determined monomial algebras are 2-$d$-Koszul algebras and the structure
of the ideal of relations of such an algebra is completely determined.


title:
New CO detections of lensed submillimeter galaxies in A2218: Probing
  molecular gas in the LIRG regime at high redshift

abstract:
  Context: Submillimeter galaxies (SMGs) are distant, dusty galaxies undergoing
star formation at prodigious rates. Recently there has been major progress in
understanding the nature of the bright SMGs (i.e. S(850um)>5mJy). The samples
for the fainter SMGs are small and are currently in a phase of being built up
through identification studies. Aims: We study the molecular gas content in two
SMGs, SMMJ163555 and SMMJ163541, at z=1.034 and z=3.187 with unlensed submm
fluxes of 0.4mJy and 6.0mJy. Both SMGs are gravitationally lensed by the
foreground cluster A2218. Methods: IRAM Plateau de Bure Interferometry
observations at 3mm were obtained for the lines CO(2-1) for SMMJ163555 and
CO(3-2) for SMMJ163541. Additionally we obtained CO(4-3) for the candidate
z=4.048 SMMJ163556 with an unlensed submm flux of 2.7mJy. Results: CO(2-1) was
detected for SMMJ163555 at z=1.0313 with an integrated line intensity of
1.2+-0.2Jy km/s and a line width of 410+-120 km/s. From this a gas mass of
1.6x10^9 Msun is derived and a star formation efficiency of 440Lsun/Msun is
estimated. CO(3-2) was detected for SMMJ163541 at z=3.1824, possibly with a
second component at z=3.1883, with an integrated line intensity of 1.0+-0.1 Jy
km/s and a line width of 280+-50 km/s. From this a gas mass of 2.2x10^10 Msun
is derived and a star formation efficiency of 1000 Lsun/Msun is estimated. For
SMMJ163556 the CO(4-3) is undetected within the redshift range 4.035-4.082 down
to a sensitivity of 0.15 Jy km/s. Conclusions: Our CO line observations confirm
the optical redshifts for SMMJ163555 and SMMJ163541. The CO line luminosity
L'_CO for both galaxies is consistent with the L_FIR-L'_CO relation. SMMJ163555
has the lowest FIR luminosity of all SMGs with a known redshift and is one of
the few high redshift LIRGs whose properties can be estimated prior to ALMA.


title:
The volume of causal diamonds, asymptotically de Sitter space-times and
  irreversibility

abstract:
  In this note we prove that the volume of a causal diamond associated with an
inertial observer in asymptotically de Sitter 4-dimensional space-time is
monotonically increasing function of cosmological time. The asymptotic value of
the volume is that of in maximally symmetric de Sitter space-time. The
monotonic property of the volume is checked in two cases: in vacuum and in the
presence of a massless scalar field. In vacuum, the volume flow (with respect
to cosmological time) asymptotically vanishes if and only if future space-like
infinity is 3-manifold of constant curvature. The volume flow thus represents
irreversibility of asymptotic evolution in spacetimes with positive
cosmological constant.


title:
Fluctuations in the Ionizing Background During and After Helium
  Reionization

abstract:
  The radiation background above the ionization edge of HeII varies strongly
during and after helium reionization, because the attenuation length of such
photons is relatively short (<40 Mpc) and because the ionizing sources
(quasars) are rare. Here we construct analytic and Monte Carlo models to
examine these fluctuations, including, for the first time, those during the
reionization era itself. In agreement with detailed numerical simulations, our
analytic model for the post-reionization Universe predicts order-of-magnitude
fluctuations in the HeII ionization rate. Observations of the hardness ratio
between HeII/HI show even larger fluctuations, which may be due to more
complicated radiative transfer effects. During reionization, the fluctuations
are even stronger. In contrast to hydrogen reionization, our model predicts
that regions with strong HeII Lyman-alpha forest transmission should be
reasonably common even during the beginning stages of reionization, because of
strong illumination from bright quasars. Partly due to this, the mean ionizing
background does not evolve strongly during and after helium reionization; it is
roughly proportional to the filling fraction of HeIII regions. On the other
hand, regions full of HeII and also "fossil" ionized regions that contain no
(or few) active sources appear as strong IGM absorbers. Their presence
exaggerates the evolution of the hardness ratio, making it evolve faster than
naively expected during the reionization era.


title:
AGN jet physics from measurements of the frequency-dependent position of
  the VLBI radio core

abstract:
  Accurate measurement of the frequency-dependent shift of the self-absorbed
radio core is required for multi-frequency analysis of VLBI data since absolute
positional information is lost as a result of phase self-calibration. We use
the cross-correlation technique of Croke & Gabuzda (2008) on the optically thin
jet emission to align our VLBA images. Our results are consistent with those
obtained from the phase-referencing method, as well as alignment by
model-fitted optically thin jet components. Physical parameters of the compact
jet regions, such as the magnetic field strength (B_core) and the distance of
the radio core to the jet origin (r_core), can be calculated from these
measurements. For the source Mrk 501, we find a magnetic field strength of
0.15\pm0.04 G in the 8.4-GHz core at a distance of 0.8\pm0.2 pc from the base
of the jet. By extrapolating our 4.6 to 15.4 GHz results for BL Lac (2200+420),
we estimate magnetic field strengths of the order of 1 G in the millimetre VLBI
core. Using our core-shift measurement between 1.6 and 4.8 GHz for 1803+784, we
find B_core(4.8 GHz) = 0.11\pm0.02 G and r_core(4.8 GHz) = 20\pm5 pc. The
phase-referencing observations of this source at 8.4 and 43 GHz by
Jim\'enez-Monferrer et al. (2008) imply B_core(43 GHz) = 1.0\pm0.4 G and
r_core(43 GHz) = 2.0\pm0.9 pc.


title: The shape of primordial non-Gaussianity and the CMB bispectrum

abstract:
  We present a set of formalisms for comparing, evolving and constraining
primordial non-Gaussian models through the CMB bispectrum. We describe improved
methods for efficient computation of the full CMB bispectrum for any general
(non-separable) primordial bispectrum, incorporating a flat sky approximation
and a new cubic interpolation. We review all the primordial non-Gaussian models
in the present literature and calculate the CMB bispectrum up to l <2000 for
each different model. This allows us to determine the observational
independence of these models by calculating the cross-correlation of their CMB
bispectra. We are able to identify several distinct classes of primordial
shapes - including equilateral, local, warm, flat and feature (non-scale
invariant) - which should be distinguishable given a significant detection of
CMB non-Gaussianity. We demonstrate that a simple shape correlator provides a
fast and reliable method for determining whether or not CMB shapes are well
correlated. We use an eigenmode decomposition of the primordial shape to
characterise and understand model independence. Finally, we advocate a
standardised normalisation method for $f_{NL}$ based on the shape
autocorrelator, so that observational limits and errors can be consistently
compared for different models.


title: Photo-z optimization for measurements of the BAO radial direction

abstract:
  Baryon Acoustic Oscillations (BAO) in the radial direction offer a method to
directly measure the Universe expansion history, and to set limits to space
curvature when combined to the angular BAO signal. In addition to spectroscopic
surveys, radial BAO might be measured from accurate enough photometric
redshifts obtained with narrow-band filters. We explore the requirements for a
photometric survey using Luminous Red Galaxies (LRG) to competitively measure
the radial BAO signal and discuss the possible systematic errors of this
approach. If LRG were a highly homogeneous population, we show that the photo-z
accuracy would not substantially improve by increasing the number of filters
beyond $\sim 10$, except for a small fraction of the sources detected at high
signal-to-noise, and broad-band filters would suffice to achieve the target
$\sigma_z = 0.003 (1+z)$ for measuring radial BAO. Using the LRG spectra
obtained from SDSS, we find that the spectral variability of LRG substantially
worsens the achievable photometric redshift errors, and that the optimal system
consists of $\sim$ 30 filters of width $\Delta \lambda / \lambda \sim 0.02$. A
$S/N > 20$ is generally necessary at the filters on the red side of the
$H\alpha$ break to reach the target photometric accuracy. We estimate that a
5-year survey in a dedicated telescope with etendue in excess of 60 ${\rm m}^2
{\rm deg}^2$ would be necessary to obtain a high enough density of galaxies to
measure radial BAO with sufficiently low shot noise up to $z= 0.85$. We
conclude that spectroscopic surveys have a superior performance than
photometric ones for measuring BAO in the radial direction.


title: Stability of equilibria for the $\mathfrak{so}(4)$ free rigid body

abstract:
  The stability for all generic equilibria of the Lie-Poisson dynamics of the
$\mathfrak{so}(4)$ rigid body dynamics is completely determined. It is shown
that for the generalized rigid body certain Cartan subalgebras (called of
coordinate type) of $\mathfrak{so}(n)$ are equilibrium points for the rigid
body dynamics. In the case of $\mathfrak{so}(4)$ there are three coordinate
type Cartan subalgebras whose intersection with a regular adjoint orbit give
three Weyl group orbits of equilibria. These coordinate type Cartan subalgebras
are the analogues of the three axes of equilibria for the classical rigid body
in $\mathfrak{so}(3)$. In addition to these coordinate type Cartan equilibria
there are others that come in curves.


title: Conformal kernel for NLO BFKL equation in ${\cal N}$=4 SYM

abstract:
  Using the requirement of M\"{o}bius invariance of ${\cal N}$=4 SYM amplitudes
in the Regge limit we restore the conformal NLO BFKL kernel out of the
eigenvalues known from the forward NLO BFKL result.