title: Cosmic microwave background bispectrum on small angular scales

abstract:
  This article investigates the non-linear evolution of cosmological
perturbations on sub-Hubble scales in order to evaluate the unavoidable
deviations from Gaussianity that arise from the non-linear dynamics. It shows
that the dominant contribution to modes coupling in the cosmic microwave
background temperature anisotropies on small angular scales is driven by the
sub-Hubble non-linear evolution of the dark matter component. The perturbation
equations, involving in particular the first moments of the Boltzmann equation
for the photons, are integrated up to second order in perturbations. An
analytical analysis of the solutions gives a physical understanding of the
result as well as an estimation of its order of magnitude. This allows to
quantify the expected deviation from Gaussianity of the cosmic microwave
background temperature anisotropy and, in particular, to compute its bispectrum
on small angular scales. Restricting to equilateral configurations, we show
that the non-linear evolution accounts for a contribution that would be
equivalent to a constant primordial non-Gaussianity of order fNL~25 on scales
ranging approximately from l~1000 to l~3000.


title: Search for Single Top Production at HERA

abstract:
  A search for single top production in ep collisions using the complete high
energy data from HERA is presented. This search is based on the analysis of
events containing isolated leptons (electrons or muons) and missing transverse
momentum PTmiss. In the absence of a signal, an upper limit on the top
production cross section sigma_ep -> etX < 0.16 pb is established at the 95%
confidence level, corresponding to an upper bound on the anomalous magnetic
coupling kappa_tug < 0.14. The search is complemented by a search for events
containing an isolated tau lepton and PTmiss and the measurement of W boson
polarisation fractions.


title: Cayley-Dicksonia Revisited

abstract:
  In the theory of the hypercomplex, the laws governing the algebra are based
on units that are naturally associated with an orthogonal vector space, a
requirement that is far from mandatory in many algebraic formulations arising
in the context of the reals or the complex numbers.In this article the
complementing view is held, in that the laws of hypercomplex algebra are recast
in terms of quite generally posited units. Proceeding in this manner, a
generalized form of the Cayley-Dickson process is examined. The representations
given are regular bimodular; the resulting matrices are standard except they
are allowed nonstandard multiplication for noncommutative matrix elements.


title:
Theoretical Descriptions of the Nucleon Electromagnetic Form Factors in
  the Space- and Time-like regions

abstract:
  Some recent advances in the theoretical description of the Nucleon
electromagnetic form factors, both in the space- and time-like regions, will be
briefly illustrated. In particular, both the present stage of the lattice
calculations and updated phenomenological approaches, like the ones based on
dispersion relations and on microscopical models, will be reported.


title:
Perturbative determination of $c_{SW}$ for plaquette and Symanzik gauge
  action and stout link clover fermions

abstract:
  Using plaquette and Symanzik improved gauge action and stout link clover
fermions we determine the improvement coefficient $c_{SW}$ in one-loop lattice
perturbation theory from the off-shell quark-quark-gluon three-point function.
In addition, we compute the coefficients needed for the most general form of
quark field improvement and present the one-loop result for the critical
hopping parameter $\kappa_c$. We discuss mean field improvement for $c_{SW}$
and $\kappa_c$ and the choice of the mean field coupling for the actions we
have considered.


title: Single-molecule electron diffraction imaging with charge replacement

abstract:
  We investigate the possibility of non-destructive electron diffraction
imaging of a single molecule to determine its structure. The molecular specimen
will be held on a free-standing sheet of graphene. Due to the high conductivity
of graphene, electrons lost by ionization would be rapidly replaced, enabling
repeated nondestructive interrogation. Limits of resolution, maximum particle
size and required electron flux are assessed.


title:
Scalar-tensor cosmology with R^{-1} curvature correction by Noether
  Symmetry

abstract:
  We discuss scalar-tensor cosmology with an extra $R^{-1}$ correction by the
Noether Symmetry Approach. The existence of such a symmetry selects the forms
of the coupling $\omega(\phi)$, of the potential $V(\phi)$ and allows to obtain
physically interesting exact cosmological solutions.


title: On the role of volatility in the evolution of social networks

abstract:
  We study how the volatility, node- or link-based, affects the evolution of
social networks in simple models. The model describes the competition between
order -- promoted by the efforts of agents to coordinate -- and disorder
induced by volatility in the underlying social network. We find that when
volatility affects mostly the decay of links, the model exhibit a sharp
transition between an ordered phase with a dense network and a disordered phase
with a sparse network. When volatility is mostly node-based, instead, only the
symmetric (disordered) phase exists These two regimes are separated by a second
order phase transition of unusual type, characterized by an order parameter
critical exponent $\beta=0^+$. We argue that node volatility has the same
effect in a broader class of models, and provide numerical evidence in this
direction.


title: Time Warps in Photonic Time Stretch ADC and Their Mitigation

abstract:
  We demonstrate a 10-GHz bandwidth digitizer with 7-effective bits of
resolution and 52dB SFDR, using photonic time stretch technique. To the best of
our knowledge, this is the highest resolution analog-to-digital converter (ADC)
of the same bandwidth, with at least an order of magnitude higher SNR than
previously achieved. This is made possible by correction of distortion due to
time warps, and non-linearities due to wavelength dependent bias variation in
the Mach-Zehnder modulator. We also demonstrate concatenation of 30 wavelength
interleaved time segments with high fidelity on the path to achieving
continuous time operation.


title:
Confluence of singularities of differential equation: a Lie algebra
  contraction approach

abstract:
  We investigate here the confluence of singularities of Mathieu differential
equation by means of the Lie algebra contraction of the Lie algebra of the
motion group M(2) on the Heisenberg Lie algebra H(3). A similar approach for
the Lam\'e equation in terms of the Lie algebra contraction of $SO_0(2,1)$ on
the Lie algebra of the motion group M(2) is outlined.


title:
Short Range Correlations in Medium- and High-Energy Scattering off
  Nuclei

abstract:
  The effects of short range correlations in lepton and hadron scattering off
nuclei at medium and high energies are discussed.


title:
Ising Like Order by Disorder In The Pyrochlore Antiferromagnet with
  Dzyaloshinskii-Moriya Interactions

abstract:
  It is shown that the mechanism of order out of disorder is at work in the
antisymmetric pyrochlore antiferromagnet. Quantum as well as thermal
fluctuations break the continuous degeneracy of the classical ground state
manifold and reduce its symmetry to $\mathbb{Z}_3 \times \mathbb{Z}_2$. The
role of anisotropic symmetric exchange is also investigated and we conclude
that this discrete like ordering is robust with respect to these second order
like interactions. The antisymmetric pyrochlore antiferromagnet is therefore
expected to order at low temperatures, whatever the symmetry type of its
interactions, in both the classical and semi classical limits.


title: Two Particle Azimuthal Correlations in 4.2A GeV C+Ta Collisions

abstract:
  Two particle azimuthal correlations are studied in 4.2A GeV C+Ta collisions
observed with the 2-m propane bubble chamber exposed at JINR Dubna
Synchrophasotron. The correlations are analyzed both for protons and negative
pions, and their dependence on the collision centrality, rapidity and rapidity
difference is investigated. It is found that protons show a weak back-to-back
correlations, while a side-by-side correlations are observed for negative
pions. Restricting both protons to the target or projectile fragmentation
region, the side-by-side correlations are observed for protons also. Using the
two particle correlation function, the flow analysis is performed and intensity
of directed flow is determined without event-by event estimation of the
reaction plane.


title: A study of heuristic guesses for adiabatic quantum computation

abstract:
  Adiabatic quantum computation (AQC) is a universal model for quantum
computation which seeks to transform the initial ground state of a quantum
system into a final ground state encoding the answer to a computational
problem. AQC initial Hamiltonians conventionally have a uniform superposition
as ground state. We diverge from this practice by introducing a simple form of
heuristics: the ability to start the quantum evolution with a state which is a
guess to the solution of the problem. With this goal in mind, we explain the
viability of this approach and the needed modifications to the conventional AQC
(CAQC) algorithm. By performing a numerical study on hard-to-satisfy 6 and 7
bit random instances of the satisfiability problem (3-SAT), we show how this
heuristic approach is possible and we identify that the performance of the
particular algorithm proposed is largely determined by the Hamming distance of
the chosen initial guess state with respect to the solution. Besides the
possibility of introducing educated guesses as initial states, the new strategy
allows for the possibility of restarting a failed adiabatic process from the
measured excited state as opposed to restarting from the full superposition of
states as in CAQC. The outcome of the measurement can be used as a more refined
guess state to restart the adiabatic evolution. This concatenated restart
process is another heuristic that the CAQC strategy cannot capture.


title: Gamma Ray Burst Predictions for the Fermi Gamma Ray Space Telescope

abstract:
  Results of a phenomenological model to estimate the GRB detection rate by the
Fermi Gamma ray Space Telescope are reported. This estimate is based on the
BATSE 4B GRB fluence distribution, the mean ratio of fluences measured at 100
MeV - 5 GeV with EGRET and at 20 keV - 2 MeV with BATSE, and the mean EGRET GRB
spectrum for the 5 EGRET spark-chamber GRBs. For a 10% fluence ratio and a
number spectral index alpha_1 = -2 at 100 MeV - 5 GeV energies, we estimate a
rate of ~ 20 and 4 GRBs per yr in the Fermi Large Area Telescope field of view
with at least 5 photons with energy E > 100 MeV and E > 1 GeV, respectively. We
also estimate ~ 1.5 GRBs per yr in the Fermi FoV where at least 1 photon with
energy E > 10 GeV is detected. For these parameters, we estimate = 1 - 2 GRBs
per year detected with the Fermi telescope with more than 100 gamma rays with E
>~ 100$ MeV. Comparison predictions for alpha_1 = -2.2, different fluence
ratios, and the AGILE gamma-ray satellite are made. Searches for different
classes of GRBs using a diagram plotting 100 MeV - 10 GeV fluence vs. 20 keV -
20 MeV fluence is considered as a way to search for separate classes of GRBs
and, specifically, spectral differences between the short-hard and long
duration GRB classes, and for hard components in GRBs.


title: Nonequilibrium dephasing in Coulomb blockade quantum dots

abstract:
  We present a theory of zero-bias anomalies and dephasing rates for a
Coulomb-blockaded quantum dot, driven out of equilibrium by coupling to voltage
biased source and drain leads. We interpret our results in terms of the
statistics of voltage fluctuations in the system.


title:
Rigidity Theorems For Lagrangian Submanifolds of $C^n$ and $CP^n$ With
  Conformal Maslov Form

abstract:
  In this paper, we obtain a rigidity theorem for Lagrangian submanifolds of
$C^n$ and $CP^n$ with conformal Maslov form.


title: An Euler Poincar\'e framework for the multilayer Green Nagdhi equations

abstract:
  The Green Nagdhi equations are frequently used as a model of the wave-like
behaviour of the free surface of a fluid, or the interface between two
homogeneous fluids of differing densities. Here we show that their multilayer
extension arises naturally from a framework based on the Euler Poincare theory
under an ansatz of columnar motion. The framework also extends to the
travelling wave solutions of the equations. We present numerical solutions of
the travelling wave problem in a number of flow regimes. We find that the free
surface and multilayer waves can exhibit intriguing differences compared to the
results of single layer or rigid lid models.


title:
Scanning tunneling spectroscopy of SmFeAsO0.85: Possible evidence for
  d-wave order parameter symmetry

abstract:
  We report a scanning tunneling spectroscopy investigation of polycrystalline
SmFeAsO0.85 having a superconducting transition at 52 K. On large regions of
the sample surface the tunneling spectra exhibited V-shaped gap structures with
no coherence peaks, indicating degraded surface properties. In some regions,
however, the coherence peaks were clearly observed, and the V-shaped gaps could
be fit to the theory of tunneling into a d-wave superconductor, yielding gap
values between 8 to 8.5 meV, corresponding to the ratio 2D/KTc ~ 3.55 - 3.8,
which is slightly above the BCS weak-coupling prediction. In other regions the
spectra exhibited zero-bias conductance peaks, consistent with a d-wave order
parameter symmetry.


title: Isometric Lattice Homomorphisms between Sobolev Spaces

abstract:
  Given bounded domains $\Omega_1$ and $\Omega_2$ in $\mathds{R}^N$ and an
isometry $T$ from $W^{1,p}(\Omega_1)$ to $W^{1,p}(\Omega_2)$, we give
sufficient conditions ensuring that $T$ corresponds to a rigid motion of the
space, i.e., $Tu = \pm (u \circ \xi)$ for an isometry $\xi$, and that the
domains are congruent. More general versions of the involved results are
obtained along the way.


title:
Neutrino mass, Dark Matter and Baryon Asymmetry via TeV-Scale Physics
  without Fine-Tuning

abstract:
  We propose an extended version of the standard model, in which neutrino
oscillation, dark matter, and baryon asymmetry of the Universe can be
simultaneously explained by the TeV-scale physics without assuming unnatural
hierarchy among the mass scales. Tiny neutrino masses are generated at the
three loop level due to the exact $Z_2$ symmetry, by which stability of the
dark matter candidate is guaranteed. The extra Higgs doublet is required not
only for the tiny neutrino masses but also for successful electroweak
baryogenesis. The model provides discriminative predictions especially in Higgs
phenomenology, so that it is testable at current and future collider
experiments.


title: Exact solution of the Bernoulli matching model of sequence alignment

abstract:
  Through a series of exact mappings we reinterpret the Bernoulli model of
sequence alignment in terms of the discrete-time totally asymmetric exclusion
process with backward sequential update and step function initial condition.
Using earlier results from the Bethe ansatz we obtain analytically the exact
distribution of the length of the longest common subsequence of two sequences
of finite lengths $X,Y$. Asymptotic analysis adapted from random matrix theory
allows us to derive the thermodynamic limit directly from the finite-size
result.


title: CCCP: A CCD Controller for Counting Photons

abstract:
  CCCP, a CCD Controller for Counting Photons, is presented. This new
controller uses a totally new clocking architecture and allows to drive the CCD
in a novel way. Its design is optimized for the driving of EMCCDs at up to
20MHz of pixel rate and fast vertical transfer. Using this controller, the
dominant source of noise of EMCCDs at low flux level and high frame rate, the
Clock Induced Charges, were reduced to 0.001 - 0.0018 electron/pixel/frame
(depending of the electron multiplying gain), making efficient photon counting
possible. CCCP will be deployed in 2009 on the ESO NTT through the 3D-NTT1
project and on the SOAR through the BTFI project.


title: Proton dissociation into three jets

abstract:
  We explore the possibility to observe hard exclusive three-jet production in
early LHC runs, corresponding to diffractive dissociation of the incident
proton into three jets with large but compensating transverse momenta. This
process is sensitive to the proton unintegrated gluon distribution at small x
and to the distribution of the three valence quarks in the proton at small
transverse distances. The corresponding cross section is calculated using an
approach based on k_t factorization. According to our estimates, observation of
hard diffractive three-jet production at LHC is feasible for jet transverse
momenta q_perp \sim 5 GeV.


title: Evaluating the three-loop static quark potential

abstract:
  This is a status report of the evaluation of the three-loop corrections to
the static QCD potential of a heavy quark and an antiquark. The families of
Feynman integrals that appear in the evaluation are described. To reduce any
integral of the families to master integrals we solve integration-by-parts
relations by the algorithm called FIRE. To evaluate the corresponding master
integrals we apply the Mellin-Barnes technique. First results are presented:
the coefficients of n_l^3 and n_l^2, where n_l is the number of light quarks.


title: Photon-Induced Physics with Heavy-Ion Beams in ALICE

abstract:
  The possibilities to study ultra-peripheral collisions, in particular
exclusive vector meson production, with the ALICE detector is reviewed.


title:
Quadratic Morawetz inequalities and asymptotic completeness in the
  energy space for nonlinear Schr"odinger and Hartree equations

abstract:
  Recently several authors have developed multilinear and in particular
quadratic extensions of the classical Morawetz inequality. Those extensions
provide (among other results) an easy proof of asymptotic completeness in the
energy space for nonlinear Schr"odinger equations in arbitrary space dimension
and for Hartree equations in space dimension greater than two in the
noncritical cases. We give a pedagogical review of the latter results.


title: Orbifolding the Membrane Action

abstract:
  We study a simple class of orbifolds of the N=6 Chern-Simons Matter theory
proposed by Aharony, Bergman, Jafferis and Maldacena. They are considered as a
world volume theory of membranes probing C^4/ (Z_k x Z_n) and include a new
membrane theory with N=4 supersymmetries. We find that the moduli spaces of
them are consistent with the fact that they probe C^4/ (Z_k x Z_n).


title: Berezin transform in polynomial Bergman spaces

abstract:
  We study the reproducing kernel for weighted polynomial Bergman spaces and
consider applications to the Berezin transform. Some of our results have
applications in random matrix theory, a topic which we discuss in a separate
(companion) paper.


title:
A nonlinear superposition rule for solutions of the Milne--Pinney
  equation

abstract:
  A superposition rule for two solutions of a Milne--Pinney equation is
derived.


title:
Comment on 'Molybdenum at High Pressure and Temperature: Melting from
  Another Solid Phase'

abstract:
  There has been a major controversy over the past seven years about the
high-pressure melting curves of transition metals. Static compression
(diamond-anvil cell: DAC) experiments up to the Mbar region give very low
melting slopes dT_m/dP, but shock-wave (SW) data reveal transitions indicating
much larger dT_m/dP values. Ab initio calculations support the correctness of
the shock data. In a very recent letter, Belonoshko et al. propose a simple and
elegant resolution of this conflict for molybdenum. Using ab initio
calculations based on density functional theory (DFT), they show that the
high-P/high-T phase diagram of Mo must be more complex than was hitherto
thought. Their calculations give convincing evidence that there is a transition
boundary between the normal bcc structure of Mo and a high-T phase, which they
suggest could be fcc. They propose that this transition was misinterpreted as
melting in DAC experiments. In confirmation, they note that their boundary also
explains a transition seen in the SW data. We regard Belonoshko et al.'s Letter
as extremely important, but we note that it raises some puzzling questions, and
we believe that their proposed phase diagram cannot be completely correct. We
have calculated the Helmholtz and Gibbs free energies of the bcc, fcc and hcp
phases of Mo, using essentially the same quasiharmonic methods as used by
Belonoshko et al.; we find that at high-P and T Mo in the hcp structure is more
stable than in bcc or fcc.


title: EconoThermodynamics, or the world economy "thermal death" paradox

abstract:
  The paper present one of attempts to apply the thermodynamics laws to
economics. Introducing common thermodynamic parameters and considering world
economics as a one macrosystem, authors demonstrate the possible consequences
of entropy increasing due to irreversible economics activities. "Entropy"
advices to leaders of different business units are presented.


title: Small exotic rational surfaces without 1- and 3-handles

abstract:
  We give new rational blowdown constructions of exotic CP^2#n(-CP^2) (5\leq
n\leq 9) without using elliptic fibrations. We also show that our 4-manifolds
admit handle decompositions without 1- and 3-handles, for 7\leq n\leq 9. A
strategy for rational blowdown constructions of exotic CP^2#n(-CP^2) (1\leq
n\leq 4) is also proposed.


title:
Reversible quantum optical data storage based on resonant Raman optical
  field excited spin coherence

abstract:
  A method of reversible quantum optical data storage is presented using
resonant Raman field excited spin coherence, where the spin coherence is stored
in an inhomogeneously broadened spin ensemble. Unlike the photon echo method,
present technique uses a 2 pi Raman optical rephasing pulse, and multimode
(parallel) optical channels can be utilized, where the multimode access gives a
great benefit to both all-optical and quantum information processing.


title: Fluctuations of eigenvalues of random normal matrices

abstract:
  In this note, we prove Gaussian field convergence of fluctuations of
eigenvalues of random normal matrices in the interior of a quantum droplet.


title: Galaxy And Mass Assembly (GAMA)

abstract:
  The GAMA survey aims to deliver 250,000 optical spectra (3--7Ang resolution)
over 250 sq. degrees to spectroscopic limits of r_{AB} <19.8 and K_{AB}<17.0
mag. Complementary imaging will be provided by GALEX, VST, UKIRT, VISTA,
HERSCHEL and ASKAP to comparable flux levels leading to a definitive
multi-wavelength galaxy database. The data will be used to study all aspects of
cosmic structures on 1kpc to 1Mpc scales spanning all environments and out to a
redshift limit of z ~ 0.4. Key science drivers include the measurement of: the
halo mass function via group velocity dispersions; the stellar, HI, and
baryonic mass functions; galaxy component mass-size relations; the recent
merger and star-formation rates by mass, types and environment. Detailed
modeling of the spectra, broad SEDs, and spatial distributions should provide
individual star formation histories, ages, bulge-disc decompositions and
stellar bulge, stellar disc, dust disc, neutral HI gas and total dynamical
masses for a significant subset of the sample (~100k) spanning both the giant
and dwarf galaxy populations. The survey commenced March 2008 with 50k spectra
obtained in 21 clear nights using the Anglo Australian Observatory's new
multi-fibre-fed bench-mounted dual-beam spectroscopic system (AAOmega).


title: Quantum states and localisation of developable Moebius nanostructures

abstract:
  The equilibrium equations for wide, developable, Moebius strips undergoing
large deformations have recently been derived, and solved, numerically. We use
these results to compute the eigenvalues and eigenstates of non-interacting
electrons confined to Moebius strips of linking number up to 1.5 and of
arbitrary width. The inverse participation ratio is used to show that electrons
are increasingly localised to the higher curvature regions of the higher-width
structures, where sharp creases could form channels for particle transport. Our
geometric formulation could be used to study transport properties of Moebius
strip and other components in nanoscale devices.


title:
Nano Imprint Lithography on Silica Sol-gels: a simple route to
  sequential patterning

abstract:
  Since the pioneering work of S.Y. Chou et al.[1] Nano Imprint Lithography
(NIL) has emerged as a promising technique for surface patterning, opening for
numerous applications ranging from nanophotonics[2] to microfluidics[3]. NIL
basically consists in the stamping of deformable surfaces or films. Preferred
materials are thermoplastics[4] and UV curable resists[5]. So far, most papers
report on single imprinting methods for which the same surface is imprinted
only once. In the present paper, we report the imprinting of square silica
structures from simple line gratings and demonstrate how the specific
thermo-rheological behavior of ICSG resists can be harnessed to form complex
structures by sequential imprinting at low pressures.


title: Dynamics of nonequilibrium thermal entanglement

abstract:
  The dynamics of a simple spin chain (2 spins) coupled to bosonic baths at
different temperatures is studied. The analytical solution for the reduced
density matrix of the system is found. The dynamics and temperature dependence
of spin-spin entanglement is analyzed. It is shown that the system converges to
a steady-state. If the energy levels of the two spins are different, the
steady-state concurrence assumes its maximum at unequal bath temperatures. It
is found that a difference in local energy levels can make the steady-state
entanglement more stable against high temperatures.


title: Strong lensing in the Einstein-Straus solution

abstract:
  We analyse strong lensing in the Einstein-Straus solution with positive
cosmological constant. For concreteness we compare the theory to the light
deflection of the lensed quasar SDSS J1004+4112.


title: Lattice QCD and Flavour Physics

abstract:
  I report on recent progress and future prospects for lattice QCD calculations
relevant for flavour physics and CP violation. I will focus on lattice studies
that incorporate realistic vacuum polarization effects, i.e., with n_f=2+1 sea
quarks.


title: Parametric Decay of the Curvaton

abstract:
  We argue that the curvaton decay takes place most naturally by way of a broad
parametric resonance. The mechanism is analogous to resonant inflaton decay but
does not require any tuning of the curvaton coupling strength to other scalar
fields. For low scale inflation and a correspondingly low mass scale for the
curvaton, we speculate on observable consequences including the possibility of
stochastic gravitational waves


title:
Some Combinatorial Properties of Hook Lengths, Contents, and Parts of
  Partitions

abstract:
  This paper proves a generalization of a conjecture of Guoniu Han, inspired
originally by an identity of Nekrasov and Okounkov. The main result states that
certain sums over partitions p of n, involving symmetric functions of the
squares of the hook lengths of p, are polynomial functions of n. A similar
result is obtained for symmetric functions of the contents and shifted parts of
n.


title:
Fluids of spherical molecules with dipolar-like nonuniform adhesion. An
  analytically solvable anisotropic model

abstract:
  We consider an anisotropic version of Baxter's model of `sticky hard
spheres', where a nonuniform adhesion is implemented by adding, to an isotropic
surface attraction, an appropriate `dipolar sticky' correction (positive or
negative, depending on the mutual orientation of the molecules). The resulting
nonuniform adhesion varies continuously, in such a way that in each molecule
one hemisphere is `stickier' than the other. We derive a complete analytic
solution by extending a formalism [M.S. Wertheim, J. Chem. Phys. \textbf{55},
4281 (1971) ] devised for dipolar hard spheres. Unlike Wertheim's solution
which refers to the `mean spherical approximation', we employ a
\textit{Percus-Yevick closure with orientational linearization}, which is
expected to be more reliable. We obtain analytic expressions for the
orientation-dependent pair correlation function $g(1,2) $. Only one equation
for a parameter $K$ has to be solved numerically. We also provide very accurate
expressions which reproduce $K$ as well as some parameters, $\Lambda_{1}$ and
$\Lambda_{2}$, of the required Baxter factor correlation functions with a
relative error smaller than 1%. We give a physical interpretation of the
effects of the anisotropic adhesion on the $g(1,2) $. The model could be useful
for understanding structural ordering in complex fluids within a unified
picture.


title: A bilinear form relating two Leonard systems

abstract:
  Let $\Phi$, $\Phi'$ be Leonard systems over a field $\mathbb{K}$, and $V$,
$V'$ the vector spaces underlying $\Phi$, $\Phi'$, respectively. In this paper,
we introduce and discuss a balanced bilinear form on $V\times V'$. Such a form
naturally arises in the study of $Q$-polynomial distance-regular graphs. We
characterize a balanced bilinear form from several points of view.


title:
Spin decoherence of a heavy hole coupled to nuclear spins in a quantum
  dot

abstract:
  We theoretically study the interaction of a heavy hole with nuclear spins in
a quasi-two-dimensional III-V semiconductor quantum dot and the resulting
dephasing of heavy-hole spin states. It has frequently been stated in the
literature that heavy holes have a negligible interaction with nuclear spins.
We show that this is not the case. In contrast, the interaction can be rather
strong and will be the dominant source of decoherence in some cases. We also
show that for unstrained quantum dots the form of the interaction is
Ising-like, resulting in unique and interesting decoherence properties, which
might provide a crucial advantage to using dot-confined hole spins for quantum
information processing, as compared to electron spins.


title:
Josephson Junctions as Threshold Detectors of the Full Counting
  Statistics: Open issues

abstract:
  I study the dynamics of a Josephson junction serving as a threshold detector
of fluctuations which is subjected to a general non-equilibrium electronic
noise source whose characteristics is to be determined by the junction. This
experimental setup has been proposed several years ago as a prospective scheme
for determining the Full Counting Statistics of the electronic noise source.
Despite of intensive theoretical as well as experimental research in this
direction the promise has not been quite fulfilled yet and I will discuss what
are the unsolved issues. First, I review a general theory for the calculation
of the exponential part of the non-equilibrium switching rates of the junction
and compare its predictions with previous results found in different limiting
cases by several authors. I identify several possible weak points in the
previous studies and I report a new analytical result for the linear correction
to the rate due to the third cumulant of a non-Gaussian noise source in the
limit of a very weak junction damping. The various analytical predictions are
then compared with the results of the developed numerical method. Finally, I
analyze the status of the so-far publicly available experimental data with
respect to the theoretical predictions and discuss briefly the suitability of
the present experimental schemes in view of their potential to measure the
whole FCS of non-Gaussian noise sources as well as their relation to the
available theories.


title:
Charge carrier solvation and large polaron formation on a polymer chain
  revealed in model ab initio computations

abstract:
  When an excess charge carrier is added to a semiconducting polymer chain, it
is well known that the carrier may self-trap into a polaronic state accompanied
by a bond length adjustment pattern. A different mechanism of self-localization
is the solvation of charge carriers expected to take place when the polymer
chain is immersed in polar media such as common solvents. We use
state-of-the-art ab initio computations in conjunction with the Polarizable
Continuum Model to unequivocally demonstrate solvation-induced self-consistent
charge localization into large-radius one-dimensional (1D) polarons on long
$C_{N}H_{2}$ carbon chains with the polyynic structure. Within the framework
used, the solvation results in a much more pronounced charge localization. We
believe this mechanism of polaron formation to be of relevance for various 1D
semiconductors in polar environments.


title:
Modular properties of two-loop maximal supergravity and connections with
  string theory

abstract:
  The low-momentum expansion of the two-loop four-graviton scattering amplitude
in eleven-dimensional supergravity compactified on a circle and a two-torus is
considered up to terms of order S^6R^4 (where S is a Mandelstam invariant and R
is the linearized Weyl curvature). In the case of the toroidal compactification
the coefficient of each term in the low energy expansion is generically a sum
of a number of SL(2,Z)-invariant functions of the complex structure of the
torus. Each such function satisfies a separate Poisson equation on moduli space
with particular source terms that are bilinear in coefficients of lower order
terms, consistent with qualitative arguments based on supersymmetry. Comparison
is made with the low-energy expansion of type II string theories in ten and
nine dimensions. Although the detailed behaviour of the string amplitude is not
generally expected to be reproduced by supergravity perturbation theory to all
orders, for the terms considered here we find agreement with direct results
from string perturbation theory. These results point to a fascinating pattern
of interrelated Poisson equations for the IIB coefficients at higher orders in
the momentum expansion which may have a significance beyond the particular
methods by which they were motivated.


title: Helical motion of magnetic flux tubes in the solar atmosphere

abstract:
  Photospheric granulation may excite transverse kink pulses in anchored
vertical magnetic flux tubes. The pulses propagate upwards along the tubes with
the kink speed, while oscillating wakes are formed behind the wave front in a
stratified atmosphere. The wakes oscillate at the kink cut-off frequency of
stratified medium and gradually decay in time. When two or more consecutive
kink pulses with different polarizations propagate in the same thin tube, then
the wakes corresponding to different pulses may superimpose. The superposition
sets up helical motions of magnetic flux tubes in the photosphere/chromosphere
as seen by recent Hinode movies. The energy carried by the pulses is enough to
heat the solar chrmosphere/corona and accelerate the solar wind.


title: Worldgraph Approach to Yang-Mills Amplitudes from N=2 Spinning Particle

abstract:
  By coupling the N=2 spinning particle to background vector fields, we
construct Yang-Mills amplitudes for trees and one loop. The vertex operators
are derived through coupling the BRST charge; therefore background gauge
invariance is manifest, and the Yang-Mills ghosts are automatically included in
loop calculations by worldline ghosts. Inspired by string calculations, we
extend the usual worldline approach to incorporate more "generalized" 1D
manifolds. This new approach should be useful for constructing higher-point and
higher-loop amplitudes.


title: Heat fluctuations in Ising models coupled with two different heat baths

abstract:
  Monte Carlo simulations of Ising models coupled to heat baths at two
different temperatures are used to study a fluctuation relation for the heat
exchanged between the two thermostats in a time $\tau$. Different kinetics
(single--spin--flip or spin--exchange Kawasaki dynamics), transition rates
(Glauber or Metropolis), and couplings between the system and the thermostats
have been considered. In every case the fluctuation relation is verified in the
large $\tau $ limit, both in the disordered and in the low temperature phase.
Finite-$\tau$ corrections are shown to obey a scaling behavior.


title: Frame Combination Techniques for Ultra High-Contrast Imaging

abstract:
  We summarize here an experimental frame combination pipeline we developed for
ultra high-contrast imaging with systems like the upcoming VLT SPHERE
instrument. The pipeline combines strategies from the Drizzle technique, the
Spitzer IRACproc package, and homegrown codes, to combine image sets that may
include a rotating field of view and arbitrary shifts between frames. The
pipeline is meant to be robust at dealing with data that may contain non-ideal
effects like sub-pixel pointing errors, missing data points, non-symmetrical
noise sources, arbitrary geometric distortions, and rapidly changing point
spread functions. We summarize in this document individual steps and
strategies, as well as results from preliminary tests and simulations.


title: Hadron physics: a quark-model analysis

abstract: We discuss recent results on heavy and light baryon spectroscopy


title: Faces of the scl norm ball

abstract:
  Let F be the fundamental group of S, where S is a compact, connected,
oriented surface with negative Euler characteristic and nonempty boundary.
  (1) The projective class of the chain \partial S in B_1(F) intersects the
interior of a codimension one face of the unit ball in the stable commutator
length pseudo-norm. (2) The unique homogeneous quasimorphism on F dual to this
face (up to scale and elements of H^1) is the rotation quasimorphism associated
to the action of F on the ideal boundary of the hyperbolic plane, coming from a
hyperbolic structure on S.
  These facts follow from the fact that every homologically trivial 1-chain in
S rationally cobounds an immersed surface with a sufficiently large multiple of
the boundary. This is true even if S has no boundary.


title:
On the Origin of Logarithmic-Normal Distributions: An Analytical
  Derivation, and its Application to Nucleation and Growth Processes

abstract:
  The logarithmic-normal (lognormal) distribution is one of the most frequently
observed distributions in nature and describes a large number of physical,
biological and even sociological phenomena. The origin of this distribution is
therefore of broad interest but a general derivation from basic principles is
still lacking. Using random nucleation and growth to describe crystallization
processes we derive the time development of grain size distributions. Our
derivation provides, for the first time, an analytical expression of the size
distribution in the form of a lognormal type distribution. We apply our results
to the grain size distribution of solid phase crystallized Si-films.


title: Simulations of the formation and evolution of isolated dwarf galaxies

abstract:
  We present new fully self-consistent models of the formation and evolution of
isolated dwarf galaxies. We have used the publicly available N-body/SPH code
HYDRA, to which we have added a set of star formation criteria, and
prescriptions for chemical enrichment (taking into account contributions from
both SNIa and SNII), supernova feedback, and gas cooling. The models follow the
evolution of an initially homogeneous gas cloud collapsing in a pre-existing
dark-matter halo. These simplified initial conditions are supported by the
merger trees of isolated dwarf galaxies extracted from the milli-Millennium
Simulation.
  The star-formation histories of the model galaxies exhibit burst-like
behaviour. These bursts are a consequence of the blow-out and subsequent
in-fall of gas. The amount of gas that leaves the galaxy for good is found to
be small, in absolute numbers, ranging between 3x10^7 Msol and 6x10^7 Msol .
For the least massive models, however, this is over 80 per cent of their
initial gas mass. The local fluctuations in gas density are strong enough to
trigger star-bursts in the massive models, or to inhibit anything more than
small residual star formation for the less massive models. Between these
star-bursts there can be time intervals of several Gyrs.
  We have compared model predictions with available data for the relations
between luminosity and surface brightness profile, half-light radius, central
velocity dispersion, broad band colour (B-V) and metallicity, as well as the
location relative to the fundamental plane. The properties of the model dwarf
galaxies agree quite well with those of observed dwarf galaxies.


title:
Multiple Nodeless Superconducting Gaps in (Ba0.6K0.4)Fe2As2
  Superconductor from Angle-Resolved Photoemission Spectroscopy

abstract:
  High resolution angle-resolved photoemission measurements have been carried
out to study the superconducting gap in the (Ba0.6K0.4)Fe2As2 superconductor
with Tc=35 K. Two hole-like Fermi surface sheets around the G(0,0) point
exhibit different superconducting gaps. The inner Fermi surface sheet shows
larger (10-12 meV) and slightly momentum-dependent gap while the outer one has
smaller (7-8 meV) and nearly isotropic gap. The lack of gap node in both Fermi
surface sheets favours s-wave superconducting gap symmetry. Superconducting gap
opening is also observed at the M(pi,pi) point. The two Fermi surface spots
near the M point are gapped below Tc but the gap persists above Tc. The rich
and detailed superconducting gap information will provide key insights and
constraints in understanding pairing mechanism in the iron-based
superconductors.


title:
Four-loop perturbative Konishi from strings and finite size effects for
  multiparticle states

abstract:
  We derive the perturbative four loop anomalous dimension of the Konishi
operator in N=4 SYM theory from the integrable string sigma model by evaluating
the finite size effects using Luscher formulas adapted to multimagnon states at
weak coupling. We obtain these multiparticle generalizations of Luscher
formulas by studying certain exactly solvable relativistic integrable quantum
field theories. The final result involves a summation of all bound states in
the mirror theory and agrees with gauge theory perturbative computations.


title:
Fully adaptive multiresolution schemes for strongly degenerate parabolic
  equations in one space dimension

abstract:
  We present a fully adaptive multiresolution scheme for spatially
one-dimensional quasilinear strongly degenerate parabolic equations with
zero-flux and periodic boundary conditions. The numerical scheme is based on a
finite volume discretization using the Engquist-Osher numerical flux and
explicit time stepping. An adaptive multiresolution scheme based on cell
averages is then used to speed up the CPU time and the memory requirements of
the underlying finite volume scheme, whose first-order version is known to
converge to an entropy solution of the problem. A particular feature of the
method is the storage of the multiresolution representation of the solution in
a graded tree, whose leaves are the non-uniform finite volumes on which the
numerical divergence is eventually evaluated. Moreover using the $L^1$
contraction of the discrete time evolution operator we derive the optimal
choice of the threshold in the adaptive multiresolution method. Numerical
examples illustrate the computational efficiency together with the convergence
properties.


title:
Description of our cosmological spacetime as a perturbed conformal
  Newtonian metric and implications for the backreaction proposal for the
  accelerating universe

abstract:
  It has been argued that the spacetime of our universe can be accurately
described by a perturbed conformal Newtonian metric, and hence even large
density inhomogeneities in a dust universe can not change the observables
predicted by the homogeneous dust model. In this paper we study a spherically
symmetric dust model and illustrate conditions under which large spatial
variations in the expansion rate can invalidate the argument.


title:
Influence of thermal fluctuations on the geometry of the interfaces of
  the quenched Ising model

abstract:
  We study the role of the quench temperature $T_f$ in the phase-ordering
kinetics of the Ising model with single spin flip in $d=2,3$. Equilibrium
interfaces are flat at $T_f=0$, whereas at $T_f>0$ they are curved and rough
(above the roughening temperature in $d=3$). We show, by means of scaling
arguments and numerical simulations, that this geometrical difference is
important for the phase-ordering kinetics as well. In particular, while the
growth exponent $z=2$ of the size of domains $L(t)\sim t^{1/z}$ is unaffected
by $T_f$, other exponents related to the interface geometry take different
values at $T_f=0$ or $T_f>0$. For $T_f>0$ a crossover phenomenon is observed
from an early stage where interfaces are still flat and the system behaves as
at $T_f=0$, to the asymptotic regime with curved interfaces characteristic of
$T_f>0$. Furthermore, it is shown that the roughening length, although
sub-dominant with respect to $L(t)$, produces appreciable correction to scaling
up to very long times in $d=2$.


title:
Fully adaptive multiresolution schemes for strongly degenerate parabolic
  equations with discontinuous flux

abstract:
  A fully adaptive finite volume multiresolution scheme for one-dimensional
strongly degenerate parabolic equations with discontinuous flux is presented.
The numerical scheme is based on a finite volume discretization using the
Engquist--Osher approximation for the flux and explicit time--stepping. An
adaptivemultiresolution scheme with cell averages is then used to speed up CPU
time and meet memory requirements. A particular feature of our scheme is the
storage of the multiresolution representation of the solution in a dynamic
graded tree, for the sake of data compression and to facilitate navigation.
Applications to traffic flow with driver reaction and a clarifier--thickener
model illustrate the efficiency of this method.


title:
Violation of the scaling relation and non-Markovian nature of earthquake
  aftershocks

abstract:
  The statistical properties of earthquake aftershocks are studied. The scaling
relation for the exponents of the Omori law and the power-law calm time
distribution (i.e., the interoccurrence time distribution), which is valid if a
sequence of aftershocks is a singular Markovian process, is carefully examined.
Data analysis shows significant violation of the scaling relation, implying the
non-Markovian nature of aftershocks.


title: Surgery on a knot in (Surface x I)

abstract:
  Suppose F is a compact orientable surface, K is a knot in F x I, and N is the
3-manifold obtained by some non-trivial surgery on K. If F x {0} compresses in
N, then there is an annulus in F x I with one end K and the other end an
essential simple closed curve in F x {0}. Moreover, the end of the annulus at K
determines the surgery slope.
  An application: suppose M is a compact orientable 3-manifold that fibers over
the circle. If surgery on a knot K in M yields a reducible manifold, then
either: the projection of K to S^1 has non-trivial winding number; or K lies in
a ball; or K lies in a fiber; or K is a cabled knot.


title:
On the Algebraic Structure of Higher-Spin Field Equations and New Exact
  Solutions

abstract:
  This Thesis reviews Vasiliev's approach to Higher-Spin Gauge Theory and
contains some original results concerning new exact solutions of the Vasiliev
equations and the representation theory of the higher-spin algebra. The review
part covers the various formulations of the free theory as well as Vasiliev's
full nonlinear equations, in particular focusing on their algebraic structure
and on their properties in various space-time signatures. Then, the original
results are presented. First, the 4D Vasiliev equations are formulated in
space-times with signatures (4-p,p) and non-vanishing cosmological constant,
and some new exact solutions are found, depending on continuous and discrete
parameters: (a) an SO(4-p,p)-invariant family of solutions; (b) non-maximally
symmetric solutions with vanishing Weyl tensors and higher-spin gauge fields,
that differ from the maximally symmetric background solutions in the auxiliary
field sector; and (c) solutions of the chiral models with an infinite tower of
Weyl tensors proportional to totally symmetric products of two principal
spinors. These are apparently the first exact 4D solutions with non-vanishing
massless higher-spin fields. Finally, a generalized harmonic expansion of the
Vasiliev's master zero-form is performed as a map from the associative algebra
A of operators on the singleton phase space to representations of the
background isometry algebra that include one-particle states along with
linearized runaway solutions. Such Harish-Chandra modules are unitarizable in a
Tr_A-norm rather than in the standard Killing norm. We also take the first
steps towards a regularization scheme for handling strongly coupled
higher-derivative interactions within this operator formalism.


title:
Turning a nickelate Fermi surface into a cuprate-like one through
  heterostructuring

abstract:
  Using the local density approximation and its combination with dynamical
mean-field theory, we show that electronic correlations induce a single-sheet,
cuprate-like Fermi surface for hole-doped 1/1 LaNiO3 /LaAlO3 heterostructures,
even though both eg orbitals contribute to it. The Ni 3d 3z^2-1 orbital plays
the role of the axial Cu 4s-like orbital in the cuprates. These two results
indicate that "orbital engineering" by means of heterostructuring should be
possible. As we also find strong antiferromagnetic correlations, the low-energy
electronic and spin excitations in nickelate heterostructures resemble those of
high-temperature cuprate superconductors.


title:
Quantum free energy differences from non-equilibrium path integrals: I.
  Methods and numerical application

abstract:
  The imaginary-time path integral representation of the canonical partition
function of a quantum system and non-equilibrium work fluctuation relations are
combined to yield methods for computing free energy differences in quantum
systems using non-equilibrium processes. The path integral representation is
isomorphic to the configurational partition function of a classical field
theory, to which a natural but fictitious Hamiltonian dynamics is associated.
It is shown that if this system is prepared in an equilibrium state, after
which a control parameter in the fictitious Hamiltonian is changed in a finite
time, then formally the Jarzynski non-equilibrium work relation and the Crooks
fluctuation relation are shown to hold, where work is defined as the change in
the energy as given by the fictitious Hamiltonian. Since the energy diverges
for the classical field theory in canonical equilibrium, two regularization
methods are introduced which limit the number of degrees of freedom to be
finite. The numerical applicability of the methods is demonstrated for a
quartic double-well potential with varying asymmetry. A general parameter-free
smoothing procedure for the work distribution functions is useful in this
context.


title:
Quantum free energy differences from non-equilibrium path integrals: II.
  Convergence properties for the harmonic oscillator

abstract:
  Non-equilibrium path integral methods for computing quantum free energy
differences are applied to a quantum particle trapped in a harmonic well of
uniformly changing strength with the purpose of establishing the convergence
properties of the work distribution and free energy as the number of degrees of
freedom M in the regularized path integrals goes to infinity. The work
distribution is found to converge when M tends to infinity regardless of the
switching speed, leading to finite results for the free energy difference when
the Jarzynski non-equilibrium work relation or the Crooks fluctuation relation
are used. The nature of the convergence depends on the regularization method.
For the Fourier method, the convergence of the free energy difference and work
distribution go as 1/M, while both quantities converge as 1/M^2 when the bead
regularization procedure is used. The implications of these results to more
general systems are discussed.


title:
Decoding generalised hyperoctahedral groups and asymptotic analysis of
  correctible error patterns

abstract:
  We demonstrate a majority-logic decoding algorithm for decoding the
generalised hyperoctahedral group $C_m \wr S_n$ when thought of as an
error-correcting code. We also find the complexity of this decoding algorithm
and compare it with that of another, more general, algorithm. Finally, we
enumerate the number of error patterns exceeding the correction capability that
can be successfully decoded by this algorithm, and analyse this asymptotically.


title:
X-ray and optical observations of M55 and NGC 6366: evidence for
  primordial binaries

abstract:
  We present Chandra X-ray Observatory ACIS-S3 X-ray imaging observations and
VLT/FORS2 and Hubble Space Telescope optical observations of two low-density
Galactic globular clusters; NGC 6366 and M55. We detect 16 X-ray sources with
0.5-6.0 keV luminosities above Lx=4E30 erg/s within the half-mass radius of
M55, of which 8 or 9 are expected to be background sources, and 5 within the
half-mass radius of NGC 6366, of which 4 are expected to be background sources.
Optical counterparts are identified for several X-ray sources in both clusters
and from these we conclude that 3 of the X-ray sources in M55 and 2 or 3 of the
X-ray sources in NGC 6366 are probably related to the cluster. Combining these
results with those for other clusters, we find the best fit for a predicted
number of X-ray sources in a globular cluster Nc=1.2 Gamma+1.1 Mh, where Gamma
is the collision number and Mh is (half of) the cluster mass, both normalized
to the values for the globular cluster M4. Some sources tentatively classified
as magnetically active binaries are more luminous in X-rays than the upper
limit of Lx~0.001Lbol of such binaries in the solar neighbourhood. Comparison
with XMM and ROSAT observations lead us to conclude that the brightest X-ray
source in M55, a dwarf nova, becomes fainter in X-rays during the optical
outburst, in accordance with other dwarf novae. The brightest X-ray source in
NGC 6366 is a point source surrounded by a slightly offset extended source. The
absence of galaxies and Halpha emission in our optical observations argues
against a cluster of galaxies and against a planetary nebula, and we suggest
that the source may be an old nova.


title:
Spin 3/2 fermions with attractive interactions in a one-dimensional
  optical lattice: phase diagrams, entanglement entropy, and the effect of the
  trap

abstract:
  We study spin 3/2 fermionic cold atoms with attractive interactions confined
in a one-dimensional optical lattice. Using numerical techniques, we determine
the phase diagram for a generic density. For the chosen parameters,
one-particle excitations are gapped and the phase diagram is separated into two
regions: one where the two-particle excitation gap is zero, and one where it is
finite. In the first region, the two-body pairing fluctuations (BCS) compete
with the density ones. In the other one, a molecular superfluid (MS) phase, in
which bound-states of four particles form, competes with the density
fluctuations. The properties of the transition line between these two regions
is studied through the behavior of the entanglement entropy. The physical
features of the various phases, comprising leading correlations, Friedel
oscillations, and excitation spectra, are presented. To make the connection
with experiments, the effect of a harmonic trap is taken into account. In
particular, we emphasize the conditions under which the appealing MS phase can
be realized, and how the phases could be probed by using the density profiles
and the associated structure factor. Lastly, the consequences on the flux
quantization of the different nature of the pairing in the BCS and MS phases
are studied in a situation where the condensate is in a ring geometry.


title: Vortices in Superfluid Films on Curved Surfaces

abstract:
  We present a systematic study of how vortices in superfluid films interact
with the spatially varying Gaussian curvature of the underlying substrate. The
Gaussian curvature acts as a source for a geometric potential that attracts
(repels) vortices towards regions of negative (positive) Gaussian curvature
independently of the sign of their topological charge. Various experimental
tests involving rotating superfluid films and vortex pinning are first
discussed for films coating gently curved substrates that can be treated in
perturbation theory from flatness. An estimate of the experimental regimes of
interest is obtained by comparing the strength of the geometrical forces to the
vortex pinning induced by the varying thickness of the film which is in turn
caused by capillary effects and gravity. We then present a non-perturbative
technique based on conformal mappings that leads an exact solution for the
geometric potential as well as the geometric correction to the interaction
between vortices. The conformal mapping approach is illustrated by means of
explicit calculations of the geometric effects encountered in the study of some
strongly curved surfaces and by deriving universal bounds on their strength.


title: Sequential deconfinement of quark flavors in neutron stars

abstract:
  We suggest a scenario where the three light quark flavors are sequentially
deconfined under increasing pressure in cold asymmetric nuclear matter as
found, e.g., in neutron stars. The basis for our analysis is a chiral quark
matter model of Nambu--Jona-Lasinio (NJL) type with diquark pairing in the
spin-1 single flavor (CSL), spin-0 two flavor (2SC) and three flavor (CFL)
channels. We find that nucleon dissociation sets in at about the saturation
density, n_0, when the down-quark Fermi sea is populated (d-quark dripline) due
to the flavor asymmetry induced by beta-equilibrium and charge neutrality. At
about 3n_0 u-quarks appear and a two-flavor color superconducting (2SC) phase
is formed. The s-quark Fermi sea is populated only at still higher baryon
density, when the quark chemical potential is of the order of the dynamically
generated strange quark mass. We construct two different hybrid equations of
state (EoS) using the Dirac-Brueckner Hartree-Fock (DBHF) approach and the EoS
by Shen et al. in the nuclear matter sector. The corresponding hybrid star
sequences have maximum masses of, respectively, 2.1 and 2.0 M_sun. Two- and
three-flavor quark-matter phases exist only in gravitationally unstable hybrid
star solutions in the DBHF case, while the Shen-based EoS produce stable
configurations with a 2SC phase-component in the core of massive stars. Nucleon
dissociation via d-quark drip could act as a deep crustal heating process,
which apparently is required to explain superbusts and cooling of X-ray
transients.


title: The Asymptotics of Wilkinson's Iteration: Loss of Cubic Convergence

abstract:
  One of the most widely used methods for eigenvalue computation is the $QR$
iteration with Wilkinson's shift: here the shift $s$ is the eigenvalue of the
bottom $2\times 2$ principal minor closest to the corner entry. It has been a
long-standing conjecture that the rate of convergence of the algorithm is
cubic. In contrast, we show that there exist matrices for which the rate of
convergence is strictly quadratic. More precisely, let $T_X$ be the $3 \times
3$ matrix having only two nonzero entries $(T_X)_{12} = (T_X)_{21} = 1$ and let
$T_L$ be the set of real, symmetric tridiagonal matrices with the same spectrum
as $T_X$. There exists a neighborhood $U \subset T_L$ of $T_X$ which is
invariant under Wilkinson's shift strategy with the following properties. For
$T_0 \in U$, the sequence of iterates $(T_k)$ exhibits either strictly
quadratic or strictly cubic convergence to zero of the entry $(T_k)_{23}$. In
fact, quadratic convergence occurs exactly when $\lim T_k = T_X$. Let $X$ be
the union of such quadratically convergent sequences $(T_k)$: the set $X$ has
Hausdorff dimension 1 and is a union of disjoint arcs $X^\sigma$ meeting at
$T_X$, where $\sigma$ ranges over a Cantor set.


title: Nature of the 5f states in actinide metals

abstract:
  Actinide elements produce a plethora of interesting physical behaviors due to
the 5f states. This review compiles and analyzes progress in understanding of
the electronic and magnetic structure of the 5f states in actinide metals.
Particular interest is given to electron energy-loss spectroscopy and
many-electron atomic spectral calculations, since there is now an appreciable
library of core d -> valence f transitions for Th, U, Np, Pu, Am, and Cm. These
results are interwoven and discussed against published experimental data, such
as x-ray photoemission and absorption spectroscopy, transport measurements, and
electron, x-ray, and neutron diffraction, as well as theoretical results, such
as density-functional theory and dynamical mean-field theory.


title: Feshbach resonances in ultracold 85Rb-87Rb and 6Li-87Rb mixtures

abstract:
  We present an analysis of experimentally accessible magnetic Feshbach
resonances in ultra-cold hetero-nuclear 85Rb-87Rb and 6Li-87Rb mixtures. Using
recent experimental measurements of the triplet scattering lengths for 6Li-87Rb
and 7Li-87Rb mixtures and Feshbach resonances for one combination of atomic
states, we create model potential curves and fine tune them to reproduce the
measured resonances and to predict the location of several experimentally
relevant resonances in Li-Rb collisions. To model 85Rb-87Rb collisions, we use
accurate Rb_2 potentials obtained previously from the analysis of experiments
on 87Rb-87Rb collisions. We find resonances that occur at very low magnetic
fields, below 10 G, which may be useful for entanglement generation in optical
lattices or atom chip magnetic traps.


title: Astronomy at school: present situation and future perspectives

abstract:
  Both the basic educational contents for students and study programs for
science teachers include several topics in physics and astronomy, from the
simplest ones to others as advanced as nuclear fusion to explain stellar
evolution and space-time geometry for an approach to modern cosmology. In all
these subjects, and most often in the simplest ones, alternative conceptions
emerge, as both groups reach science course with preconstructed and consistent
models of the universe surrounding them. In this work we present a series of
basic questionings that make us reflect on the present situation of the
teaching-learning relationship in astronomy within the framework of formal
education. We then briefly explain our project aiming at finding the real
learning situation of both students and prospective primary-school teachers in
astronomical topics and, from the expected results of it, we point towards the
need to develop didactic tools that could contribute to improve formal
education in astronomy issues.


title:
Observation of Fermi-surface-dependent nodeless superconducting gaps in
  Ba0.6K0.4Fe2As2

abstract:
  The recent discovery of superconductivity in iron-arsenic compounds below a
transition temperature (Tc) as high as 55K ended the monopoly of copper oxides
(cuprates) in the family of high-Tc superconductors. A critical issue in
understanding this new superconductor, as in the case of cuprates, is the
nature, in particular the symmetry and orbital dependence, of the
superconducting gap. There are conflicting experimental results, mostly from
indirect measurements of the low energy excitation gap, ranging from one gap to
two gaps, from line nodes to nodeless gap function in momentum space. Here we
report a direct observation of the superconducting gap, including its momentum,
temperature, and Fermi surface (FS) dependence in Ba0.6K0.4Fe2As2 (Tc = 37 K)
using angle-resolved photoelectron spectroscopy. We find two superconducting
gaps with different values: a large gap (~ 12 meV) on the two small hole-like
and electron-like FS sheets, and a small gap (~ 6 meV) on the large hole-like
FS. Both gaps, closing simultaneously at the bulk Tc, are nodeless and nearly
isotropic around their respective FS sheets. The isotropic pairing interactions
are strongly orbital dependent, as the ratio 2Delta/kBTc switches from weak to
strong coupling on different bands. The same and surprisingly large
superconducting gap due to strong pairing on the two small FS, which are
connected by the (pi, 0) spin-density-wave vector in the parent compound,
strongly suggests that the pairing mechanism originates from the inter-band
interactions between these two nested FS sheets.


title:
Deviation from Tri-Bimaximal Neutrino mixing from the Charged Lepton
  Sector

abstract:
  The tri-bimaximal mixing matrix is most likely the leading order term in the
description of leptonic mixing. We derive deviations from tri-bimaximal
mixing(TBM) due to corrections from the charged lepton sector. We assume a
decoupled 2-3 symmetry, which is a $Z_2$ symmetry, in the charged lepton sector
and another $Z_2$ symmetry in the neutrino sector. The TBM is obtained in the
flavor symmetric limit. We consider deviations from the TBM form arising from
the breaking of the 2-3 symmetry in the charged lepton sector but do not
consider deviations from the breaking of the flavor symmetry in the neutrino
sector. In particular we find the size of $\sin{\theta_{13}}$ to be related to
the deviation $\sin{\theta_{12}}$ from $\sqrt{1/3}$ while the deviation of
$\sin{\theta_{23}}$ from its tri-bimaximal value is $ \sim {m_{\mu} \over
m_{\tau}}$.


title:
Navier-Stokes equations and forward-backward SDEs on the group of
  diffeomorphisms of a torus

abstract:
  We establish a connection between the strong solution to the spatially
periodic Navier-Stokes equations and a solution to a system of forward-backward
stochastic differential equations (FBSDEs) on the group of volume-preserving
diffeomorphisms of a flat torus. We construct representations of the strong
solution to the Navier-Stokes equations in terms of diffusion processes.


title: Finding Local Low-mass Supermassive Black Holes

abstract:
  The low-mass end of the supermassive black hole mass function is unknown and
difficult to determine. Here we discuss our successful program to find active
nuclei of late type "normal" galaxies using X-ray detections and
multiwavelength identifications. We conclude that most of the Chandra detected
nuclear X-ray sources are AGNs. We then outline methods of black hole mass
determination when broad emission lines are unobservable.


title: Detecting Low-Mass Supermassive Black Holes

abstract:
  We demonstrate the feasibility of uncovering supermassive black holes in
late-type, quiescent spiral galaxies by detecting signs of very low-level
nuclear activity. We use a combination of x-ray selection and multi-wavelength
follow-up. Here, we apply this technique to NGC 3184 and NGC 5457, both of type
Scd, and show that strong arguments can be made that both host AGNs.


title:
Conjecture on the analyticity of PT-symmetric potentials and the reality
  of their spectra

abstract:
  The spectrum of the Hermitian Hamiltonian $H=p^2+V(x)$ is real and discrete
if the potential $V(x)\to\infty$ as $x\to\pm\infty$. However, if $V(x)$ is
complex and PT-symmetric, it is conjectured that, except in rare special cases,
$V(x)$ must be analytic in order to have a real spectrum. This conjecture is
demonstrated by using the potential $V(x)=(ix)^a|x|^b$, where $a,b$ are real.


title:
Wireless Broadcast with Network Coding in Mobile Ad-Hoc Networks:
  DRAGONCAST

abstract:
  Network coding is a recently proposed method for transmitting data, which has
been shown to have potential to improve wireless network performance. We study
network coding for one specific case of multicast, broadcasting, from one
source to all nodes of the network. We use network coding as a loss tolerant,
energy-efficient, method for broadcast. Our emphasis is on mobile networks. Our
contribution is the proposal of DRAGONCAST, a protocol to perform network
coding in such a dynamically evolving environment. It is based on three
building blocks: a method to permit real-time decoding of network coding, a
method to adjust the network coding transmission rates, and a method for
ensuring the termination of the broadcast. The performance and behavior of the
method are explored experimentally by simulations; they illustrate the
excellent performance of the protocol.


title:
La forme asymptotique du processus de contact en environnement
  al\'eatoire

abstract:
  The aim of this article is to prove asymptotic shape theorems for the contact
process in stationary random environment. These theorems generalize known
results for the classical contact process. In particular, if H_t denotes the
set of already occupied sites at time t, we show that for almost every
environment, when the contact process survives, the set H_t/t almost surely
converges to a compact set that only depends on the law of the environment. To
this aim, we prove a new almost subadditive ergodic theorem.


title: Unchained polygons and the N-body problem

abstract:
  The simplest solutions of the N-body problem --symmetric relative
equilibria-- are shown to be organizing centers from which stem some recently
studied classes of periodic solutions. We focus on the relative equilibrium of
the equal-mass regular N-gon, assumed horizontal, and study the families of
Lyapunov quasi-periodic solutions bifurcating from them in the vertical
direction. The proof of the local existence of such solutions relies on the
fact that the restriction to the corresponding directions of the quadratic part
of the energy is positive definite. We then discuss the possibility of
continuing the families globally as action minimizers under symmetry
constraints by using the fact that, in rotating frames where they become
periodic, these solutions are highly symmetric. The paradigmatic examples are
the "Eight" families for an odd number of bodies and the "Hip-Hop" families for
an even number. We argue that it is precisely for these two families that
global minimization may be used. We also study the relation with the regular
N-gon, of the so-called "chain" choreographies (see C. Sim\'o, New families of
Solutions in N-Body Problems, Progr. Math. 201, 2001): here, only a local
minimization property is true (except for N=3) and moreover the parity plays a
deciding role, in particular through the value of the angular momentum.


title:
Dynamical deformations of three-dimensional Lie algebras in Bianchi
  classification over the harmonic oscillator

abstract:
  Operadic Lax representations for the harmonic oscillator are used to
construct the dynamical deformations of three-dimensional (3D) real Lie
algebras in the Bianchi classification. It is shown that the energy
conservation of the harmonic oscillator is related to the Jacobi identities of
the dynamically deformed algebras. Based on this observation, it is proved that
the dynamical deformations of 3D real Lie algebras in the Bianchi
classification over the harmonic oscillator are Lie algebras.


title: The phase diagram of random threshold networks

abstract:
  Threshold networks are used as models for neural or gene regulatory networks.
They show a rich dynamical behaviour with a transition between a frozen and a
chaotic phase. We investigate the phase diagram of randomly connected threshold
networks with real-valued thresholds h and a fixed number of inputs per node.
The nodes are updated according to the same rules as in a model of the
cell-cycle network of Saccharomyces cereviseae [PNAS 101, 4781 (2004)]. Using
the annealed approximation, we derive expressions for the time evolution of the
proportion of nodes in the "on" and "off" state, and for the sensitivity
$\lambda$. The results are compared with simulations of quenched networks. We
find that for integer values of h the simulations show marked deviations from
the annealed approximation even for large networks. This can be attributed to
the particular choice of the updating rule.


title: Analogue of Sylvester-Cayley formula for invariants of $n$-ary form

abstract:
  The number $\nu_{n,d}(k)$ of linearly independed homogeneous invariants of
degree $k$ for the $n$-ary form of degree $d$ is calculated.


title:
The Radio to Gamma Ray Connection of EGRET Blazars: Correlation,
  Regression and Monte Carlo Analysis

abstract:
  A comprehensive statistical analysis of the broadband properties of EGRET
blazars is presented. This analysis includes sources identified as blazars in
the Sowards-Emmerd publications. Using this sample of 122 sources, we find that
there is a relationship $L_\gamma \propto {L_r}^{0.77 \pm 0.03} $ as well as a
correlation between $\alpha_{og}$ and $\alpha_{ro}$, and a correlation between
radio luminosity and $\alpha_{og}$. Through the use of Monte Carlo simulations,
we can replicate the observed luminosity relationship if a synchrotron
self-Compton model is assumed. However, this relationship can not be replicated
if an external Compton scattering model is assumed. These differences are
primarily due to beaming effects.
  In addition it has been determined that the intrinsic radio luminosity of the
parent sample falls in the range $10^{21} < L < 10^{30} {\rm Watts Hz^{-1}}$
and that the bulk Lorentz factors of the source are in the range $ 1 < \Gamma <
30 $, in a agreement with VLBI observations.
  Finally, we discuss implications for GLAST, successfully launched in June
2008.


title:
A multiresolution space-time adaptive scheme for the bidomain model in
  electrocardiology

abstract:
  This work deals with the numerical solution of the monodomain and bidomain
models of electrical activity of myocardial tissue. The bidomain model is a
system consisting of a possibly degenerate parabolic PDE coupled with an
elliptic PDE for the transmembrane and extracellular potentials, respectively.
This system of two scalar PDEs is supplemented by a time-dependent ODE modeling
the evolution of the so-called gating variable. In the simpler sub-case of the
monodomain model, the elliptic PDE reduces to an algebraic equation. Two simple
models for the membrane and ionic currents are considered, the
Mitchell-Schaeffer model and the simpler FitzHugh-Nagumo model. Since typical
solutions of the bidomain and monodomain models exhibit wavefronts with steep
gradients, we propose a finite volume scheme enriched by a fully adaptive
multiresolution method, whose basic purpose is to concentrate computational
effort on zones of strong variation of the solution. Time adaptivity is
achieved by two alternative devices, namely locally varying time stepping and a
Runge-Kutta-Fehlberg-type adaptive time integration. A series of numerical
examples demonstrates thatthese methods are efficient and sufficiently accurate
to simulate the electrical activity in myocardial tissue with affordable
effort. In addition, an optimalthreshold for discarding non-significant
information in the multiresolution representation of the solution is derived,
and the numerical efficiency and accuracy of the method is measured in terms of
CPU time speed-up, memory compression, and errors in different norms.


title: A generalized Major index statistic

abstract:
  Inspired by the $k$-inversion statistic for LLT polynomials, we define a
$k$-inversion number and $k$-descent set for words. Using these, we define a
new statistic on words, called the $k$-major index, that interpolates between
the major index and inversion number. We give a bijective proof that the
$k$-major index is equidistributed with the major index, generalizing a
classical result of Foata and rediscovering a result of Kadell. Inspired by
recent work of Haglund and Stevens, we give a partial extension of these
definitions and constructions to standard Young tableaux. Finally, we give an
application to Macdonald polynomials made possible through connections with LLT
polynomials.


title: Higher-order Analogues of the Slice Genus of a Knot

abstract:
  For certain classes of knots we define geometric invariants called
higher-order genera. Each of these invariants is a refinement of the slice
genus of a knot. We find lower bounds for the higher-order genera in terms of
certain von Neumann $\rho$-invariants, which we call higher-order signatures.
The higher-order genera offer a refinement of the Grope filtration of the knot
concordance group.


title:
Advances in the measurement of the Lense-Thirring effect with planetary
  motions in the field of the Sun

abstract:
  E.V. Pitjeva, by processing more than 400,000 planetary observations of
various types with the dynamical models of the EPM2006 ephemerides, recently
estimated a correction to the canonical Newtonian-Einsteinian Venus' perihelion
precession of -0.0004 +/- 0.0001 arcseconds per century. The prediction of
general relativity for the Lense-Thirring precession of the perihelion of Venus
is -0.0003 arcseconds per century. It turns out that neither other
mismodelld/unmodelled standard Newtonian/Einsteinian effects nor exotic ones,
postulated to, e.g., explain the Pioneer anomaly, may have caused the
determined extra-precession of the Venus orbit which, thus, can be reasonably
attributed to the gravitomagnetic field of the Sun, not modelled in the
routines of the EPM2006 ephemerides. However, it must be noted that the quoted
error is the formal, statistical one; the realistic uncertainty might be
larger. Future improvements of the inner planets' ephemerides, with the
inclusion of the Messenger and Venus-Express tracking data, should further
improve the accuracy and the consistency of such a test of general relativity
which would also benefit of the independent estimation of the extra-precessions
of the perihelia (and the nodes) by other teams of astronomers.


title:
IP Pegasi in outburst: Echelle spectroscopy & Modulation Doppler
  Tomography

abstract:
  We analyse a unique set of time-resolved echelle spectra of the dwarf nova IP
Peg, obtained at ESO's NTT with EMMI. The dataset covers the wavelength range
of 4000-7500A and shows Balmer, HeI, HeII and heavier elements in emission. IP
Peg was observed one day after the peak of an outburst. The trailed spectra,
spectrograms and Doppler maps show characteristics typical of IP Pegasi during
the early stages of its outburst. The high-ionisation line of HeII 4686A is the
most centrally located line and has the greatest radial extension compared to
the HeI lines. The Balmer lines extend from close to the white dwarf up to
approximately 0.45 times R_L, with the outer radius gradually increasing when
moving from H delta to H alpha. The application, for the first time, of the
modulation Doppler tomography technique, maps any harmonically varying
components present in the system configuration. We find, as expected, that part
of the strong secondary star emission in Balmer and HeI lines is modulated
predominantly with the cosine term, consistent with the emission originating
from the irradiated front side of the mass-donor star, facing the accreting
white dwarf. For the Balmer lines the level of the modulation, compared to the
average emission, decreases when moving to higher series. Emission from the
extended accretion disk appears to be only weakly modulated, with amplitudes of
at most a few percent of the non-varying disk emission. We find no evidence of
modulated emission in the spiral arms, which if present, is relatively weak at
that our signal-to-noise ratio was good enough to put a lower detection limit
of any modulated emission at 5--6%. Only in one arm of the HeII 4686A line, is
there a possibility of modulated emission, but again, we cannot be sure this is
not caused by blending with the nearby Bowen complex of lines.


title: The AdS4/CFT3 algebraic curve

abstract:
  We present the OSp(2,2|6) symmetric algebraic curve for the AdS4/CFT3 duality
recently proposed in arXiv:0806.1218. It encodes all classical string solutions
at strong t'Hooft coupling and the full two loop spectrum of long single trace
gauge invariant operators in the weak coupling regime. This construction can
also be used to compute the complete superstring semi-classical spectrum around
any classical solution. We exemplify our method on the BMN point-like string.


title: Sensitivity of a Bolometric Interferometer to the CMB power spectrum

abstract:
  Context. The search for B-mode polarization fluctuations in the Cosmic
Microwave Background is one of the main challenges of modern cosmology. The
expected level of the B-mode signal is very low and therefore requires the
development of highly sensitive instruments with low systematic errors. An
appealing possibility is bolometric interferometry. Aims. We compare in this
article the sensitivity on the CMB angular power spectrum achieved with direct
imaging, heterodyne and bolometric interferometry. Methods. Using a simple
power spectrum estimator, we calculate its variance leading to the counterpart
for bolometric interferometry of the well known Knox formula for direct
imaging. Results. We find that bolometric interferometry is less sensitive than
direct imaging. However, as expected, it is finally more sensitive than
heterodyne interferometry due to the low noise of the bolometers. It therefore
appears as an alternative to direct imagers with different and possibly lower
systematic errors, mainly due to the absence of an optical setup in front of
the horns.


title: Graviton one-loop effective action and inflationary dynamics

abstract:
  We consider the one-loop effective action due to gravitons in a FLRW
background with constant epsilon=-(dH/dt)/H^2. By expanding around epsilon=0
(corresponding to an expansion around de Sitter space), we can study how the
deviation from de Sitter space effects the quantum corrected Friedmann
equations. We find that, at zeroth order in epsilon, one-loop effects induce
only a finite shift in the coupling constants. At linear order in epsilon there
is however a divergent contribution to the equations of motion. This
contribution leads to a nontrivial term in the renormalized equations that
depends logarithmically on H and thus cannot be absorbed in local counterterms.
We find that deviations due to this term are unobservably small. Our study
shows that quantum effects in quasi de Sitter space can be fundamentally
different then in de Sitter space, albeit in the case under consideration the
effect is unobservably small.


title:
EA01A/B : high-resolution HI imaging of an interacting pair of
  post-starburst (E+A) galaxies

abstract:
  We present high spatial resolution 21cm HI observations of EA01A and EA01B, a
pair of interacting post-starburst, or E+A, galaxies at z = 0.0746. Based on
optical HST/WFPC2 images, both galaxies are known to display disturbed
morphologies. They also appear to be linked by a bridge of stars. Previous HI
observations Chang et al. (2001) had already uncovered sizable quantities of
neutral gas in or near these galaxies but they lacked the spatial resolution to
locate the gas with any precision within this galactic binary system. We have
analysed deep, high resolution archival VLA observations of the couple. We find
evidence for three gaseous tidal tails; one connected to EA01A and two
emanating from EA01B. These findings confirm, independently from the optical
imaging, that (i) EA01A and EA01B are actively interacting, and that, as a
consequence, the starbursts that occurred in these galaxies were most likely
triggered by this interaction, and that (ii) 6.6+-0.9 10^9 Msun of neutral gas
are still present in the immediate vicinity of the optical bodies of both
galaxies. The HI column density is lowest at the optical positions of the
galaxies, suggesting that most of the neutral gas that is visible in our maps
is associated with the tidal arms and not with the galaxies themselves. This
might provide an explanation for the apparent lack of ongoing star formation in
these galaxies.


title: Mass Fall-back and Accretion in the Central Engine of Gamma-Ray Bursts

abstract:
  We calculate the rate of in-fall of stellar matter on an accretion disk
during the collapse of a rapidly rotating massive star, and estimate the
luminosity of the relativistic jet that results from accretion on to the
central black hole. We find that the jet luminosity remains high for about 100
seconds, at a level comparable to the typical luminosity observed in gamma-ray
bursts (GRBs). The luminosity then decreases rapidly with time for about 10^3
seconds, roughly as ~ t^-3; the duration depends on the size and rotation speed
of the stellar core. The rapid decrease of the jet power explains the steeply
declining X-ray flux observed at the end of most long duration GRBs. A X-ray
plateau is also produced by continued fall-back of matter -- either from an
extended stellar envelope or from material that failed to escape with the
supernova ejecta. In a few GRBs, the X-ray light curve is observed to drop
suddenly at the end of the plateau phase, while in others the decline is ~ t^-1
- t ^-2. These features arise naturally in the accretion model depending on the
radius and mean specific angular momentum of the stellar envelope. The
accretion model thus provides a coherent explanation for the diverse and
puzzling features observed in the early X-ray light curves of GRBs. (Abridged)


title: Solar Cycle Related Changes at the Base of the Convection Zone

abstract:
  The frequencies of solar oscillations are known to change with solar
activity. We use Principal Component Analysis to examine these changes with
high precision. In addition to the well-documented changes in solar normal mode
oscillations with activity as a function of frequency, which originate in the
surface layers of the Sun, we find a small but statistically significant change
in frequencies with an origin at and below the base of the convection zone. We
find that at r=(0.712^{+0.0097}_{-0.0029})R_sun, the change in sound speed is
\delta c^2 / c^2 = (7.23 +/- 2.08) x 10^{-5} between high and low activity.
This change is very tightly correlated with solar activity. In addition, we use
the splitting coefficients to examine the latitudinal structure of these
changes. We find changes in sound speed correlated with surface activity for r
>~ 0.9R_sun.


title: The Casimir Force in Randall Sundrum Models with q+1 dimensions

abstract:
  We evaluate the Casimir force between two parallel plates in Randall Sundrum
(RS) scenarios extended by q compact dimensions. After giving exact expressions
for one extra compact dimension (RS 6D model), we generalize to an arbitrary
number of compact dimensions. We present the complete calculation for both two
brane scenario (RSI model) and one brane scenario (RSII models) using the
method of summing over the modes. We investigate the effects of extra
dimensions on the magnitude and sign of the force, and comment on limits for
the size and number of the extra dimensions.


title:
Constraining the Nonextensive Mass Function of Halos from BAO, CMB and
  X-ray data

abstract:
  Clusters of galaxies are the most impressive gravitationally-bound systems in
the Universe and its abundance (the cluster mass function) is one important
statistics to probe the matter density parameter ($\Omega_m$) and the amplitude
of density fluctuations ($\sigma_8$). The cluster mass function is usually
described in terms of the Press-Schecther (PS) formalism where the primordial
density fluctuations are assumed to be a Gaussian random field. In previous
works we have proposed a non-Gaussian analytical extension of the PS approach
with basis on the $q$-power law distribution (PL) of the non-extensive kinetic
theory. In this paper, by applying the PL distribution to fit the observational
mass function data from X-ray highest flux-limited sample (HIFLUGCS) we find a
strong degeneracy among the cosmic parameters, $\sigma_8$, $\Omega_m$, and the
$q$ parameter from the PL distribution. A joint analysis involving recent
observations from baryon acoustic oscillation (BAO) peak and Cosmic Microwave
Background (CMB) shift parameter is carried out in order to break these
degeneracy and better constrain the physically relevant parameters. The present
results suggest that the next generation of cluster surveys will be able to
probe the quantities of cosmological interest ($\sigma_8, \Omega_m$) and the
underlying cluster physics quantified by the $q$-parameter.


title: Properties of Gamma-Ray Burst Progenitor Stars

abstract:
  We determine some basic properties of stars that produce spectacular
gamma-ray bursts at the end of their life. We assume that accretion of the
outer portion of the stellar core by a central black hole fuels the prompt
emission, and that fall-back and accretion of the stellar envelope later
produces the plateau in the X-ray light curve seen in some bursts. Using X-ray
data for three bursts we estimate the radius of the stellar core to be ~ 1-3 x
10^10 cm, and that of the stellar envelope to be ~ 1-2 x 10^11 cm. The density
profile in the envelope is fairly shallow, with \rho ~ r^-2. The rotation
speeds of the core and envelope are ~ 0.05 and ~ 0.2 of the local Keplerian
speed, respectively.


title: Strongly interacting bosons in a disordered optical lattice

abstract:
  Disorder, prevalent in nature, is intimately involved in such spectacular
effects as the fractional quantum Hall effect and vortex pinning in type-II
superconductors. Understanding the role of disorder is therefore of fundamental
interest to materials research and condensed matter physics. Universal
behavior, such as Anderson localization, in disordered non-interacting systems
is well understood. But, the effects of disorder combined with strong
interactions remains an outstanding challenge to theory. Here, we
experimentally probe a paradigm for disordered, strongly-correlated bosonic
systems-the disordered Bose-Hubbard (DBH) model-using a Bose-Einstein
condensate (BEC) of ultra-cold atoms trapped in a completely characterized
disordered optical lattice. We determine that disorder suppresses condensate
fraction for superfluid (SF) or coexisting SF and Mott insulator (MI) phases by
independently varying the disorder strength and the ratio of tunneling to
interaction energy. In the future, these results can constrain theories of the
DBH model and be extended to study disorder for strongly-correlated fermionic
particles.


title:
The graviton one-loop effective action in cosmological space-times with
  constant deceleration

abstract:
  We consider the quantum Friedmann equations which include one-loop vacuum
fluctuations due to gravitons and scalar field matter in a FLRW background with
constant $\epsilon=-{\dot{H}}/{H^2}$. After several field redefinitions, to
remove the mixing between the gravitational and matter degrees of freedom, we
can construct the one loop correction to the Friedmann equations. Due to
cosmological particle creation, the propagators needed in such a calculation
are typically infrared divergent. In this paper we construct the graviton and
matter propagators, making use of the recent construction of the infrared
finite scalar propagators calculated on a compact spatial manifold in
\cite{Janssen:2008px}. The resulting correction to the Friedman equations is
suppressed with respect to the tree level contribution by a factor of
$H^2/m_p^2$ and shows no secular growth.


title:
Homogeneous and isotropic cosmologies with nonlinear electromagnetic
  radiation

abstract:
  In this paper I examine cosmological models that contain a stochastic
background of nonlinear electromagnetic radiation. I show that for Born-Infeld
electrodynamics the equation of state parameter, $w=P/\rho$, remains close to
1/3 throughout the evolution of the universe if $E^2=B^2$ in the late universe
to a high degree of accuracy.
  Theories with electromagnetic Lagrangians of the form $L=-{1/4}F^2+\alpha
F^4$ have recently been studied in magnetic universes, where the electric field
vanishes. It was shown that the $F^4$ term can produce a bounce in the early
universe, avoiding an initial singularity. Here I show that the inclusion of an
electric field, with $E^2\simeq B^2$ in the late universe, eliminates the
bounce and the universe "begins" in an initial singularity.
  I also examine theories with Lagrangians of the form $L=-{1/4}F^2-\mu^8/F^2$,
which have been shown to produce a period of late time accelerated expansion in
magnetic universes. I show that, if an electric field is introduced, the
accelerated phase will only occur if $E^2<3B^2$.


title: Ultra-hard fluid and scalar field in the Kerr-Newman metric

abstract:
  An analytic solution for the accretion of ultra-hard perfect fluid onto a
moving Kerr-Newman black hole is found. This solution is a generalization of
the previously known solution by Petrich, Shapiro and Teukolsky for a Kerr
black hole. Our solution is not applicable for an extreme black hole due to
violation of the test fluid approximation. We also present a stationary
solution for a massless scalar field in the metric of a Kerr-Newman naked
singularity.


title: Thermomagnetic Effects in Vortex Liquid: Transport Entropy Revisited

abstract:
  Traditionally the Nernst and Ettingshausen effects in the vortex liquid are
described in terms of the "transport entropy" of vortices, S_d. According to
current theories, the main contribution to S_d is originated from the
electromagnetic free energy, F^{em}, which includes kinetic and magnetic energy
of superconducting currents circulating around vortex cores. However, this
concept contradicts the London postulate, according to which a supercurrent
consists of macroscopic number of particles in a single quantum state and does
not transfer any entropy. Here we resolve this contradiction and show that the
transport entropy is just ordinary thermodynamic entropy transferred by cores.
Only in this form the theory becomes simultaneously consistent with the London
postulate and the Onsager principle. The revised theory explains measured
temperature dependence S_d. The linear increase of S_d at low temperatures is
determined by the entropy of electrons in the core, then S_d reaches a maximum
at roughly T_c/2 and then vanishes due to increase of the background entropy.


title: Modeling Excitable Systems: Reentrant Tachycardia

abstract:
  Excitable membranes are an important type of nonlinear dynamical system and
their study can be used to provide a connection between physical and biological
circuits. We discuss two models of excitable membranes important in cardiac and
neural tissues. One model is based on the Fitzhugh-Nagumo equations and the
other is based on a three-transistor excitable circuit. We construct a circuit
that simulates reentrant tachycardia and its treatment by surgical ablation.
This project is appropriate for advanced undergraduates as a laboratory
capstone project, or as a senior thesis or honors project, and can also be a
collaborative project, with one student responsible for the computational
predictions and another for the circuit construction and measurements.


title: Electric Quadrupole Moments of Metastable States of Ca+, Sr+, and Ba+

abstract:
  Electric quadrupole moments of the metastable nd3/2 and nd5/2 states of Ca+,
Sr+, and Ba+ are calculated using the relativistic all-order method including
all single, double, and partial triple excitations of the Dirac-Hartree-Fock
wave function to provide recommended values for the cases where no experimental
data are available. The contributions of all non-linear single and double terms
are also calculated for the case of Ca+ for comparison of our approach with the
CCSD(T) results. The third-order many body perturbation theory is used to
evaluate contributions of high partial waves and the Breit interaction. The
remaining omitted correlation corrections are estimated as well. Extensive
study of the uncertainty of our calculations is carried out to establish
accuracy of our recommended values to be 0.5% - 1% depending on the particular
ion. Comprehensive comparison of our results with other theoretical values and
experiment is carried out. Our result for the quadrupole moment of the 3d5/2
state of Ca+ ion, 1.849(17)ea_0^2, is in agreement with the most precise recent
measurement 1.83(1)ea_0^2 by Roos et al. [Nature 443, 316 (2006)].


title: The rank of a hypergeometric system

abstract:
  The holonomic rank of the A-hypergeometric system M_A(\beta) is the degree of
the toric ideal I_A for generic parameters; in general, this is only a lower
bound. To the semigroup ring of A we attach the ranking arrangement and use
this algebraic invariant and the exceptional arrangement of nongeneric
parameters to construct a combinatorial formula for the rank jump of
M_A(\beta). As consequences, we obtain a refinement of the stratification of
the exceptional arrangement by the rank of M_A(\beta) and show that the Zariski
closure of each of its strata is a union of translates of linear subspaces of
the parameter space. These results hold for generalized A-hypergeometric
systems as well, where the semigroup ring of A is replaced by a nontrivial
weakly toric module M contained in \CC[\ZZ A]. We also provide a direct proof
of the result of M. Saito and W. Traves regarding the isomorphism classes of
M_A(\beta).