title: Particle Production at RHIC

abstract:
  Identified hadron spectra and ratios provide a unique tool to study the bulk
particle production in heavy-ion collisions and explore the QCD phase diagram.
In these proceedings we present the analysis of charged pion, kaon and
(anti)proton distributions from sqrt(s_NN)=200 and 62.4 GeV Cu+Cu collisions,
collected by the STAR experiment. New measurements extend the systematic
studies of bulk properties, addressing the energy and the system size
dependence of freeze-out parameters at RHIC. The available centrality selection
of Cu+Cu data bridge the gap between the smaller d+Au and larger Au+Au systems,
allowing a detailed study of baryon relative to meson and strangeness
production as function of system size.


title: Perturbative Approach on Financial Markets

abstract:
  We study the point of transition between complete and incomplete financial
models thanks to Dirichlet Forms methods. We apply recent techniques,
developped by Bouleau, to hedging procedures in order to perturbate parameters
and stochastic processes, in the case of a volatility parameter fixed but
uncertain for traders; we call this model Perturbed Black Scholes (PBS) Model.
We show that this model can reproduce at the same time a smile effect and a
bid-ask spread; we exhibit the volatility function associated to the
local-volatility model equivalent to PBS model when vanilla options are
concerned.
  Lastly, we present a connection between Error Theory using Dirichlet Forms
and Utility Function Theory.


title:
Response of polar nanoregions in 68%Pb(Mg1/3Nb2/3)O3-32%PbTiO3 to a
  [001] electric field

abstract:
  We report neutron diffuse scattering measurements on a single crystal of
68%Pb(Mg1/3Nb2/3)O3-32%PbTiO3. Strong diffuse scattering is observed at low
temperatures. An external field applied along the [001] direction affects the
diffuse scattering in the (HK0) plane significantly, suggesting a
redistribution occurs between polar nanoregions of different polarizations
perpendicular to the field. By contrast, the [001] field has no effect on the
diffuse scattering in the (HOL) and (0KL) zones.


title: Exact many-electron ground states on diamond and triangle Hubbard chains

abstract:
  We construct exact ground states of interacting electrons on triangle and
diamond Hubbard chains. The construction requires (i) a rewriting of the
Hamiltonian into positive semidefinite form, (ii) the construction of a
many-electron ground state of this Hamiltonian, and (iii) the proof of the
uniqueness of the ground state. This approach works in any dimension, requires
no integrability of the model, and only demands sufficiently many microscopic
parameters in the Hamiltonian which have to fulfill certain relations. The
scheme is first employed to construct exact ground state for the diamond
Hubbard chain in a magnetic field. These ground states are found to exhibit a
wide range of properties such as flat-band ferromagnetism and correlation
induced metallic, half-metallic or insulating behavior, which can be tuned by
changing the magnetic flux, local potentials, or electron density. Detailed
proofs of the uniqueness of the ground states are presented. By the same
technique exact ground states are constructed for triangle Hubbard chains and a
one-dimensional periodic Anderson model with nearest-neighbor hybridization.
They permit direct comparison with results obtained by variational techniques
for f-electron ferromagnetism due to a flat band in CeRh3B2.


title:
A Positive-Weight Next-to-Leading Order Monte Carlo Simulation of
  Drell-Yan Vector Boson Production

abstract:
  The positive weight next-to-leading-order (NLO) matching scheme (POWHEG) is
applied to Drell-Yan vector boson production in the Herwig++ Monte Carlo event
generator. This approach consistently combines the NLO calculation and parton
shower simulation, without the production of negative weight events. The
simulation includes a full implementation of the truncated shower required to
correctly describe soft emissions in an angular-ordered parton shower, for the
first time. The results are compared with Tevatron W and Z production data and
predictions for the transverse momentum spectrum of gauge bosons at the LHC
presented.


title:
Common Features in Electronic Structure of the Fe-Based Layered
  Superconductors from Photoemission Spectroscopy

abstract:
  High resolution photoemission measurements have been carried out on
non-superconducting LaOFeAs parent compound and various superconducting
R(O1-xFx)FeAs (R=La, Ce and Pr) compounds. We found that the parent LaOFeAs
compound shows a metallic character. Through extensive measurements, we have
identified several common features in the electronic structure of these
Fe-based compounds: (1). 0.2 eV feature in the valence band; (2). A universal
13~16 meV feature; (3). A clear Fermi cutoff showing zero leading-edge shift in
the superconducting state;(4). Lack of superconducting coherence peak(s); (5).
Near EF spectral weight suppression with decreasing temperature. These
universal features can provide important information about band structure,
superconducting gap and pseudogap in these Fe-based materials.


title: Chiral Symmetry and Heavy-Ion Collisions

abstract:
  I revisit the phase structure of hot and dense matter out of quarks and
gluons with some historical consideration on the color deconfinement and chiral
phase transitions. My goal is to make clear which part of the QCD phase diagram
is under theoretical control and which part is not. I demonstrate that an
uncommon but logically possible scenario other than the standard phase diagram
cannot be ruled out. My emphasis is on the concern that one should correctly
understand what kind of phenomenon occurs associated with the phase boundary
line on the diagram. It is not quite obvious, in particular, where chiral
symmetry restoration plays a phenomenological role in the temperature and
baryon density plane except at the QCD (chiral) critical point.


title: Detectability of Gravitational Waves from Phase Transitions

abstract:
  Gravitational waves potentially represent our only direct probe of the
universe when it was less than one second old. In particular, first-order phase
transitions in the early universe can generate a stochastic background of
gravitational waves which may be detectable today. We briefly summarize the
physical sources of gravitational radiation from phase transitions and present
semi-analytic expressions for the resulting gravitational wave spectra from
three distinct realistic sources: bubble collisions, turbulent plasma motions,
and inverse-cascade helical magnetohydrodynamic turbulence. Using
phenomenological parameters to describe phase transition properties, we
determine the region of parameter space for which gravitational waves can be
detected by the proposed Laser Interferometer Space Antenna. The electroweak
phase transition is detectable for a wide range of parameters.


title: Fifteen new T dwarfs discovered in the UKIDSS Large Area Survey

abstract:
  We present the discovery of fifteen new T2.5-T7.5 dwarfs (with estimated
distances between ~24-93pc, identified in the first three main data releases of
the UKIRT Infrared Deep Sky Survey. This brings the total number of T dwarfs
discovered in the Large Area Survey (to date) to 28. These discoveries are
confirmed by near infrared spectroscopy, from which we derive spectral types on
the unified scheme of Burgasser et al. (2006). Seven of the new T dwarfs have
spectral types of T2.5-T4.5, five have spectral types of T5-T5.5, one is a
T6.5p, and two are T7-7.5. We assess spectral morphology and colours to
identify T dwarfs in our sample that may have non-typical physical properties
(by comparison to solar neighbourhood populations). The colours of the full
sample of LAS T dwarfs show a possible trend to bluer Y-J with decreasing
effective temperature beyond T8. By accounting for the main sources of
incompleteness (selection, follow-up and spatial) as well as the effects of
unresolved binarity and Malmquist bias, we estimate that there are 17+-4 >=T4
dwarfs in the J<=19 volume of the LAS second data release. Comparing this to
theoretical predictions is most consistent with a sub-stellar mass function
exponent alpha between -1.0 and 0. This is consistent with the latest
2MASS/SDSS constraint (which is based on lower number statistics), and is
significantly lower than the alpha~1.0 suggested by L dwarf field populations,
possibly a result of the lower mass range probed by the T dwarf class.


title: Unveiling the nature of six HMXBs through IR spectroscopy

abstract:
  The International Gamma-Ray Astrophyiscs Laboratory (INTEGRAL) is discovering
a large number of new hard X-ray sources, many of them being HMXBs. The
identification and spectral characterization of their optical/infrared
counterparts is a necessary step to undertake detailed study of these systems.
In particular, the determination of the spectral type is crucial in the case of
the new class of Supergiant Fast X-ray Transients (SFXTs), which show X-ray
properties common to other objects. We used the ESO/NTT SofI spectrograph to
observe proposed IR counterparts to HMXBs, obtaining Ks medium resolution
spectra (R = 1320) with a S/N >= 100. We classified them through comparison
with published atlases. We were able to spectrally classify the six sources.
This allowed us to ascribe one of them to the new class of SFXTs and confirm
the membership of two sources to this class. We confirmed the spectral
classification, derived from optical spectroscopy, of a known system, 4U
1907-09, showing for the first time its infrared spectrum. The spectral
classification was also used to estimate the distance of the sources. We
compared the extinction as derived from X-ray data with effective interstellar
extinction obtained from our data, discussing the absorption component due to
the circumstellar environment, which we observed in four systems; in
particular, intrinsic absorption seems to emerge as a typical feature of the
entire class of SFXTs.


title:
Semi-classical equation of state and specific heats for neutron-star
  inner crust with proton shell corrections

abstract:
  An approach to the equation of state for the inner crust of neutron stars
based on Skyrme-type forces is presented. Working within the Wigner-Seitz
picture, the energy is calculated by the TETF (temperature-dependent extended
Thomas-Fermi) method, with proton shell corrections added self-consistently by
the Strutinsky-integral method. Using a Skyrme force that has been fitted to
both neutron matter and to essentially all the nuclear mass data, we find
strong proton shell effects: proton numbers $Z$ = 50, 40 and 20 are the only
values possible in the inner crust, assuming that nuclear equilibrium is
maintained in the cooling neutron star right down to the ambient temperature.
  Convergence problems with the TETF expansion for the entropy, and our way of
handling them, are discussed. Full TETF expressions for the specific heat of
inhomogeneous nuclear matter are presented. Our treatment of the electron gas,
including its specific heat, is essentially exact, and is described in detail.


title: A 15 deg Wide Field of View Imaging Air Cherenkov Telescope

abstract:
  Contemporary imaging air Cherenkov telescopes (IACT) for ground-based very
high energy (VHE) gamma ray astronomy have prime focus optical design.
Typically these telescopes have a 2-4 deg wide field of view (FoV). They use
f/0.7-f/1.2 optics and provide 3-10 arcmin resolution in the FoV. Generally, a
well designed telescope that includes more than one optical element will offer
some advantages not available in prime focus designs, such as a wider FoV, a
more compact size, a higher and more homogeneous resolution and a lower degree
of isochronous distortion of light rays focused onto the focal plane. Also,
they allow monitoring the gamma ray activity in a sizeable portion of the sky
in a single observation. This would allow one to perform a sensitive all-sky
survey in a relative short time. We present an f/0.8 15 deg wide FoV telescope
design, which provides a high and near uniform resolution and low isochronous
distortion across the entire FoV.


title:
HD 179949b: A Close Orbiting Extrasolar Giant Planet with a
  stratosphere?

abstract:
  We have carried out a search for the 2.14 micron spectroscopic signature of
the close orbiting extrasolar giant planet, HD 179949b. High cadence time
series spectra were obtained with the CRIRES spectrograph at VLT1 on two
closely separated nights. Deconvolution yielded spectroscopic profiles with
mean S/N ratios of several thousand, enabling the near infrared contrast ratios
predicted for the HD 179949 system to be achieved.
  Recent models have predicted that the hottest planets may exhibit spectral
signatures in emission due to the presence of TiO and VO which may be
responsible for a temperature inversion high in the atmosphere. We have used
our phase dependent orbital model and tomographic techniques to search for the
planetary signature under the assumption of an absorption line dominated
atmospheric spectrum, where T and V are depleted from the atmospheric model,
and an emission line dominated spectrum, where TiO and VO are present.
  We do not detect a planet in either case, but the 2.120 - 2.174 micron
wavelength region covered by our observations enables the deepest near infrared
limits yet to be placed on the planet/star contrast ratio of any close orbiting
extrasolar giant planet system. We are able to rule out the presence of an
atmosphere dominated by absorption opacities in the case of HD 179949b at a
contrast ratio of F_p/F_* ~ 1/3350, with 99 per cent confidence.


title: Symmetry and monotonicity of least energy solutions

abstract:
  We give a simple proof of the fact that for a large class of quasilinear
elliptic equations and systems the solutions that minimize the corresponding
energy in the set of all solutions are radially symmetric. We require just
continuous nonlinearities and no cooperative conditions for systems. Thus, in
particular, our results cannot be obtained by using the moving planes method.
In the case of scalar equations, we also prove that any least energy solution
has a constant sign and is monotone with respect to the radial variable.


title:
The two-loop functional renormalization-group approach to the one- and
  two-dimensional Hubbard model

abstract:
  We consider the application of the two-loop functional renormalization-group
(fRG) approach to study the low-dimensional Hubbard model. This approach
accounts for both, the universal and non-universal contributions to the RG
flow. While the universal contributions were studied previously within the
field-theoretical RG for the one-dimensional Hubbard model with linearized
electronic dispersion and the two-dimensional Hubbard model with flat Fermi
surface, the non-universal contributions appear to be important for the flow of
the vertices and susceptibilities at large momenta scales. The two-loop fRG
approach is also applied to the two-dimensional Hubbard model with a curved
Fermi surface and the van Hove singularities near the Fermi level. The vertices
and susceptibilities in the end of the flow of the two-loop approch are
suppressed in comparison with both the one-loop approach with vertex projection
and the modified one-loop approach with corrected vertex projection errors. The
results of the two-loop approach are closer to the results of one-loop approach
with the projected vertices, the difference of the results of one- and two-loop
fRG approaches decreases when going away from the van Hove band filling. The
quasiparticle weight remains finite in two dimensions at not too low
temperatures above the paramagnetic ground state.


title: Hard scattering and QCD Fundamentals at RHIC

abstract:
  In 1998, at the 4th QCD workshop, Rolf Baier asked me whether jets could be
measured in Au+Au collisions because he had a prediction of a QCD medium-effect
(energy loss via soft gluon radiation induced by multiple scattering) on
color-charged partons traversing a hot-dense-medium composed of screened
color-charges. I reviewed the possibilities in a talk explaining that there was
a general consensus that for Au+Au central collisions at $\sqrt{s_{NN}}=200$
GeV, leading particles are the only way to find jets because of the large
particle density. The good news was that hard-scattering in p-p collisions was
originally observed by the method of leading particles and that these
techniques could be used to study hard-scattering and jets in Au+Au collisions.
Notably, I described ``How everything you want to know about jets can be found
using 2-particle correlations''. In fact, the predicted ``jet quenching'' and
other new phenomena were discovered by this method. However, this past year, I
had to soften the statement to {\em almost everything} because we found by
explicit calculation in PHENIX that the away-side two-particle correlation
$p_{T_a}$ spectrum from a $\pi^0$ trigger with $p_{T_t}$ is not sensitive to
the fragmentation function--overturning a belief dating from the seminal paper
of Feynman, Field and Fox in 1977. A new formula was derived which showed that
the shape of the $p_{T_a}$ spectrum depends only on the power $n$ of the parton
invariant cross section so that NLO pQCD calculations of the two particle
away-side correlations are, in fact, less sensitive to the shape of the
fragmentation function than calculations of the inclusive $\pi^0$ cross
section.


title:
The FP420 R&D Project: Higgs and New Physics with forward protons at the
  LHC

abstract:
  We present the FP420 R&D project, which has been studying the key aspects of
the development and installation of a silicon tracker and fast-timing detectors
in the LHC tunnel at 420 m from the interaction points of the ATLAS and CMS
experiments. These detectors would measure precisely very forward protons in
conjunction with the corresponding central detectors as a means to study
Standard Model (SM) physics, and to search for and characterise New Physics
signals. This report includes a detailed description of the physics case for
the detector and, in particular, for the measurement of Central Exclusive
Production, pp --> p + phi + p, in which the outgoing protons remain intact and
the central system phi may be a single particle such as a SM or MSSM Higgs
boson. Other physics topics discussed are gamma-gamma and gamma-p interactions,
and diffractive processes. The report includes a detailed study of the trigger
strategy, acceptance, reconstruction efficiencies, and expected yields for a
particular p p --> p H p measurement with Higgs boson decay in the b-bbar mode.
The document also describes the detector acceptance as given by the LHC beam
optics between the interaction points and the FP420 location, the machine
backgrounds, the new proposed connection cryostat and the moving ("Hamburg")
beam-pipe at 420 m, and the radio-frequency impact of the design on the LHC.
The last part of the document is devoted to a description of the 3D silicon
sensors and associated tracking performances, the design of two fast-timing
detectors capable of accurate vertex reconstruction for background rejection at
high-luminosities, and the detector alignment and calibration strategy.


title:
Classifications of special double-coverings associated to a
  non-orientable surface

abstract:
  This paper investigates some actions "\`a la Johnson" on the set, denoted by
${\cal E}$, of Spin-structures which are interpreted as special
double-coverings of a trivial $S^1-$fibration over a non-orientable surface
$N_{g+1}$. The group acting is first a group of orthogonal isomorphisms
assoiciated to $N_{g+1}$. A second approach is to consider the subspace of
${\cal E}$ (with $2^{g}$ elements) coming from special double-coverings of
$S^1\times F_g$, where $F_g$ is the orientation covering of $N_{g+1}$. The
group acting now is a subgroup of the group of symplectic isomorphisms
associated to $F_{g}$. In both situations, we obtain results on the number of
orbits and the number of elements in each orbit. Except in one case, these
results do not depend on any necessary choices. We compare both previous
classifications to a third one: weak-equivalence of coverings


title: On the closedness of approximation spectra

abstract:
  Generalizing Cusick's theorem on the closedness of the classical Lagrange
spectrum for the approximation of real numbers by rational ones, we prove that
various approximation spectra are closed, using penetration properties of the
geodesic flow in cusp neighbourhoods in negatively curved manifolds and a
result of Maucourant.


title: Parton shower evolution in a 3-d hydrodynamical medium

abstract:
  We present a Monte Carlo simulation of the perturbative Quantum
Chromodynamics (pQCD) shower developing after a hard process embedded in a
heavy-ion collision. The main assumption is that the cascade of branching
partons traverses a medium which (consistent with standard radiative energy
loss pictures) is characterized by a local transport coefficient qhat which
measures the virtuality per unit length transferred to a parton which
propagates in this medium. This increase in parton virtuality alters the
development of the shower and in essence leads to extra induced radiation and
hence a softening of the momentum distribution in the shower. After
hadronization, this leads to the concept of a medium-modified fragmentation
function. On the level of observables, this is manifest as the suppression of
high transverse momentum (PT) hadron spectra. We simulate the soft medium
created in heavy-ion collisions by a 3-d hydrodynamical evolution and average
the medium-modified fragmentation function over this evolution in order to
compare with data on single inclusive hadron suppression and extract the qhat
which characterizes the medium. Finally, we discuss possible uncertainties of
the model formulation and argue that the data in a soft momentum show evidence
of qualitatively different physics which presumably cannot be described by a
medium-modified parton shower.


title: The Gauss higher relative class number problem

abstract:
  Assuming the 2-adic Iwasawa main conjecture, we find all CM fields with
higher relative class number at most 16: there are at least 31 and at most 34
such fields, and exactly one is not abelian.


title: Risk Premium Impact in the Perturbative Black Scholes Model

abstract:
  We study the risk premium impact in the Perturbative Black Scholes model. The
Perturbative Black Scholes model, developed by Scotti, is a subjective
volatility model based on the classical Black Scholes one, where the volatility
used by the trader is an estimation of the market one and contains measurement
errors. In this article we analyze the correction to the pricing formulas due
to the presence of an underlying drift different from the risk free return. We
prove that, under some hypothesis on the parameters, if the asset price is a
sub-martingale under historical probability, then the implied volatility
presents a skewed structure, and the position of the minimum depends on the
risk premium $\lambda$.


title: Scalar Extension of Abelian and Tannakian Categories

abstract:
  We introduce and develop the notion of scalar extension for abelian
categories. Given a field extension F'/F, to every F-linear abelian category A
satisfying a suitable finiteness condition we associate an F'-linear abelian
category A' and an exact F-linear functor t: A --> A'. This functor is
universal among F-linear right exact functors with target an F'-linear abelian
category.
  We discuss various basic properties of this concept, among others
compatibilities with multilinear endofunctors such as tensor products, and the
permanence of favourable properties of the functors and categories involved. We
obtain the notion of scalar extension for Tannakian categories, which allows us
to deduce consequences for the algebraic monodromy groups of Tannakian
categories.


title: Representation of Finite Abelian Group Elements by Subsequence Sums

abstract:
  Let $G\cong C_{n_1}\oplus ... \oplus C_{n_r}$ be a finite and nontrivial
abelian group with $n_1|n_2|...|n_r$. A conjecture of Hamidoune says that if
$W=w_1... w_n$ is a sequence of integers, all but at most one relatively prime
to $|G|$, and $S$ is a sequence over $G$ with $|S|\geq |W|+|G|-1\geq |G|+1$,
the maximum multiplicity of $S$ at most $|W|$, and $\sigma(W)\equiv 0\mod |G|$,
then there exists a nontrivial subgroup $H$ such that every element $g\in H$
can be represented as a weighted subsequence sum of the form
$g=\sum_{i=1}^{n}w_is_i$, with $s_1... s_n$ a subsequence of $S$. We give two
examples showing this does not hold in general, and characterize the
counterexamples for large $|W|\geq {1/2}|G|$.
  A theorem of Gao, generalizing an older result of Olson, says that if $G$ is
a finite abelian group, and $S$ is a sequence over $G$ with $|S|\geq
|G|+D(G)-1$, then either every element of $G$ can be represented as a
$|G|$-term subsequence sum from $S$, or there exists a coset $g+H$ such that
all but at most $|G/H|-2$ terms of $S$ are from $g+H$. We establish some very
special cases in a weighted analog of this theorem conjectured by Ordaz and
Quiroz, and some partial conclusions in the remaining cases, which imply a
recent result of Ordaz and Quiroz. This is done, in part, by extending a
weighted setpartition theorem of Grynkiewicz, which we then use to also improve
the previously mentioned result of Gao by showing that the hypothesis $|S|\geq
|G|+D(G)-1$ can be relaxed to $|S|\geq |G|+d^*(G)$, where
$d^*(G)=\Sum_{i=1}^{r}(n_i-1)$. We also use this method to derive a variation
on Hamidoune's conjecture valid when at least $d^*(G)$ of the $w_i$ are
relatively prime to $|G|$.


abstract:
  Electron and phonon correlations in systems of one-dimensional electrons
coupled to phonons are studied at low temperatures by emphasizing on the effect
of electron-phonon backward scattering. It is found that the $2k_F$-wave
components of the electron density and phonon displacement field share the same
correlations. Both correlations are quasi-long-ranged for a single conducting
chain coupled to one-dimensional or three-dimensional phonons, and they are
long-ranged for repulsive electron-electron interactions for a
three-dimensional array of parallel one-dimensional conducting chains coupled
to three-dimensional phonons.


title:
On the Probability of the Existence of Fixed-Size Components in Random
  Geometric Graphs

abstract:
  In this work we give precise asymptotic expressions on the probability of the
existence of fixed-size components at the threshold of connectivity for random
geometric graphs.


title:
The nature of cosmological singularities in isotropic universes and
  braneworlds

abstract:
  We explore the character of finite-time singularities that are possible to
arise in FRW universes and in specific braneworld configurations. For FRW
universes, we derive a first classification of singularities that is based on
the behaviour of the Hubble rate. We further extend and complete this
classification with the use of the Bel-Robinson energy. The braneworld models
that we study consist of a three-brane embedded in a five-dimensional bulk
space that is inhabited by a scalar field or a perfect fluid. Our analysis that
is performed with the method of asymptotic splittings shows that these
braneworlds can exhibit three main types of singularities that arise within
finite distance from the brane.


title: Screening of magnetic moments in PuAm alloy : LDA+DMFT study

abstract:
  The puzzling absence of Pu magnetic moments in a PuAm environment is explored
using the self-consistent Dynamical Mean Field Theory (DMFT) calculations in
combination with the Local Density Approximation. We argue that delta-Pu -Am
alloys provide an ideal test bed for investigating the screening of moments
from the single impurity limit to the dense limit. Several important effects
can be studied: volume expansion, shift of the bare Pu on-site f energy level,
and the reduction of the hybridization cloud resulting from the collective
character of the Kondo effect in the Anderson lattice. These effects compensate
each other and result in a coherence scale, which is independent of alloy
composition, and is around 800K. We emphasize the role of the DMFT
self-consistency condition, and multiplet splittings in Pu and Am atoms, in
order to capture the correct value of the coherence scale in the alloy.


title:
GuiLiner: A Configurable and Extensible Graphical User Interface for
  Scientific Analysis and Simulation Software

abstract:
  The computer programs most users interact with daily are driven by a
graphical user interface (GUI). However, many scientific applications are used
with a command line interface (CLI) for the ease of development and increased
flexibility this mode provides. Scientific application developers would benefit
from being able to provide a GUI easily for their CLI programs, thus retaining
the advantages of both modes of interaction. GuiLiner is a generic, extensible
and flexible front-end designed to ``host'' a wide variety of data analysis or
simulation programs. Scientific application developers who produce a correctly
formatted XML file describing their program's options and some of its
documentation can immediately use GuiLiner to produce a carefully implemented
GUI for their analysis or simulation programs.


title: Inclusive Radiative $J/\psi$ Decays

abstract:
  Using data taken with the CLEO-c detector at the Cornell Electron Storage
Ring, we have investigated the direct photon momentum spectrum in the decay
J/psi->gamma+gluon+gluon, via the 'tagged' process: e+e- -> psi(2S);
psi(2S)->J/psi pi+pi-; J/psi->photon + X. Including contributions from two-body
radiative decay processes, we find the ratio of the inclusive direct photon
branching fraction to that of the dominant three-gluon branching fraction to be
R=0.137+/-0.001+/-0.016+/-0.004, where the errors shown are statistical,
systematic, and the model-dependent uncertainty related to the extrapolation to
zero photon energy. The shape of the scaled photon energy spectrum in J/psi->gg
gamma is observed to be very similar to that of Upsilon(1S)->gg gamma. The R
value obtained is roughly consistent with that expected by a simple
quark-charge scaling of the value determined at the Upsilon(1S), but somewhat
higher than the value expected from the running of the strong coupling
constant.


title:
An application of the tensor virial theorem to hole + vortex + bulge
  systems

abstract:
  The tensor virial theorem for subsystems is formulated for three-component
systems and further effort is devoted to a special case where the inner
subsystems and the central region of the outer one are homogeneous, the last
surrounded by an isothermal homeoid. The virial equations are explicitly
written under additional restrictions. An application is made to hole + vortex
+ bulge systems, in the limit of flattened inner subsystems. Using the
Faber-Jackson relation, the standard $M_{\rm H}$-$\sigma_0$ form is deduced
from qualitative considerations. The projected bulge velocity dispersion to
projected vortex velocity ratio, $\eta$, as a function of the fractional
radius, y_{\rm BV}, and the fractional masses, $m_{\rm BH}$, and $m_{\rm VH}$,
is plotted for several cases. It is shown that a fixed value of $\eta$ below
the maximum corresponds to two different configurations: a compact bulge on the
left and an extended bulge on the right. In addition, for fixed $m_{\rm BH}$ or
$m_{\rm BV}$, and $y_{\rm BV}$, more massive bulges are related to larger
$\eta$ and vice versa. The model is applied to NGC 4374 and NGC 4486, and the
bulge mass is inferred and compared with results from different methods. In
presence of a massive vortex $(m_{\rm VH}=5)$, the hole mass has to be reduced
by a factor 2-3 with respect to the case of a massless vortex, to get the fit.


title:
Photo-induced, non-equilibrium spin and charge polarization in quantum
  rings

abstract:
  We investigate the spin-dependent dynamical response of a quantum ring with a
spin-orbit interaction upon the application of linearly polarized, picosecond,
asymmetric electromagnetic pulses. The oscillations of the generated dipole
moment are sensitive to the parity of the occupation number in the ring and to
the strength of the spin-orbit coupling. It is shown how the associated
emission spectrum can be controlled via the pulse strength or a gate voltage.
In addition, we inspect how a static magnetic flux can modify the
non-equilibrium dynamics. In presence of the spin-orbit interaction and for a
paramagnetic ring, the applied pulse results in a spin-split, non-equilibrium
local charge density. The resulting temporal spin polarization is directed
perpendicular to the light-pulse polarization axis and oscillates periodically
with the frequency of the spin-split charge density. The spin-averaged
non-equilibrium charge density possesses a left-right symmetry with respect to
the pulse polarization axis. The calculations presented here are applicable to
nano-meter rings fabricated in heterojuctions of III-V and II-VI semiconductors
containing several hundreds electrons.


title: A Study of Quasar Proximity in O VI Absorbers at z=2-3

abstract:
  (Abridged) With the goal of investigating the nature of OVI absorbers at high
redshifts, we study the effects of proximity to the background quasar. In a
sample of sixteen quasars at z(QSO) between 2.14 and 2.87 observed at 6.6 km/s
resolution with VLT/UVES, we detect 35 OVI absorption-line systems lying within
8000 km/s of z(QSO). The systems can be categorized into 9 strong and 26 weak
OVI absorbers. The strong absorbers are defined by the presence of either
broad, fully saturated OVI absorption or partial coverage of the continuum
source, and have log N(OVI)>~15.0; these systems are intrinsic to the AGN. The
weak (narrow) systems show no partial coverage or saturation, and are
characterized by log N(OVI)<14.5 and have a median total velocity width of only
42 km/s. The incidence dN/dz of weak OVI systems within 2000 km/s of the quasar
is 42+/-12. Between 2000 and 8000 km/s, dN/dz falls to 14+/-4, equal to the
incidence of intervening OVI absorbers. Whereas the accompanying H I and C IV
column densities are significantly lower (by a mean of ~1 dex) in the weak OVI
absorbers within 2000 km/s of z(QSO) than in those at larger velocities, the
OVI column densities display no dependence on proximity. Furthermore,
significant offsets between the HI and OVI centroids in ~50% of the weak
absorbers imply that (at least in these cases) the HI and OVI are not formed in
the same phase of gas. In summary, we find no firm evidence that quasar
radiation influences the OVI-bearing gas, suggesting the OVI is collisionally
ionized rather than photoionized, possibly in the multi-phase halos of
foreground galaxies. Non-equilibrium collisional ionization models are needed
to explain the low temperatures in the absorbing gas, which are implied by
narrow line widths (b<14 km/s) in over half of the observed OVI components.


title: Disassembling the Galaxy with angle-action coordinates

abstract:
  Angle-action coordinates are used to study the relic of an N-body simulation
of a self-gravitating satellite galaxy that was released on a short-period
orbit within the disc of the Galaxy. Satellite stars that lie within 1.5 kpc of
the Sun are confined to a grid of patches in action space. As the relic
phase-mixes for longer, the patches become smaller and more numerous. These
patches can be seen even when the angle-action coordinates of an erroneous
Galactic potential are used, but using the wrong potential displaces them.
Diagnostic quantities constructed from the angle coordinates both allow the
true potential to be identified, and the relic to be dated. Hence when the full
phase space coordinates of large numbers of solar-neighbourhood stars are
known, it should be possible to identify members of particular relics from the
distribution of stars in an approximate action space. This would then open up
the possibility of determining the time since the relic was disrupted and
gaining better knowledge of the Galactic potential.
  The availability of angle-action coordinates for arbitrary potentials is the
key to these developments. The paper includes a brief introduction to the torus
technique used to generate them.


title:
Acceleration Operators in the Value Iteration Algorithms for Average
  Reward Markov Decision Processes

abstract:
  One of the most widely used methods for solving average cost MDP problems is
the value iteration method. This method, however, is often computationally
impractical and restricted in size of solvable MDP problems. We propose
acceleration operators that improve the performance of the value iteration for
average reward MDP models. These operators are based on two important
properties of Markovian operator: contraction mapping and monotonicity. It is
well known that the classical relative value iteration methods for average cost
criteria MDP do not involve the max-norm contraction or monotonicity property.
To overcome this difficulty we propose to combine acceleration operators with
variants of value iteration for stochastic shortest path problems associated
average reward problems.


title:
Existence of Global Solution of the Cauchy Problem for the Relativistic
  Boltzmann Equation with Hard Interactions

abstract:
  By using the DiPerna and Lions techniques for the nonrelativistic Boltzmann
equation, it is shown that there exists a global mild solution to the Cauchy
problem for the relativistic Boltzmann equation with the assumptions of the
relativistic scattering cross section including some relativistic hard
interactions and the initial data satifying finite mass, ``inertia'', energy
and entropy.


title: Eight-quark interactions as a chiral thermometer

abstract:
  A NJL Lagrangian extended to six and eight quark interactions is applied to
study temperature effects (SU(3) flavor limit, massless case), and (realistic
massive case). The transition temperature can be considerably reduced as
compared to the standard approach, in accordance with recent lattice
calculations. The mesonic spectra built on the spontaneously broken vacuum
induced by the 't Hooft interaction strength, as opposed to the commonly
considered case driven by the four-quark coupling, undergoes a rapid crossover
to the unbroken phase, with a slope and at a temperature which is regulated by
the strength of the OZI violating eight-quark interactions. This strength can
be adjusted in consonance with the four-quark coupling and leaves the spectra
unchanged, except for the sigma meson mass, which decreases. A first order
transition behavior is also a possible solution within the present approach.


title: Gamma-ray emission of relativistic jets as a supercritical process

abstract:
  Supercriticality of the same kind as that in a nuclear pile can take place in
high-energy astrophysical objects producing a number of impressive effects. For
example, it could cause an explosive release of the energy of a cloud of
ultrarelativistic protons into radiation. More certainly, supercriticality
should be responsible for energy dissipation of very energetic relativistic
fluids such as ultrarelativistic shocks in gamma-ray bursts and jets in active
galactic nuclei (AGNs). In this case, the photon breeding process operates. It
is a kind of the converter mechanism with the high-energy photons and e^+ e^-
pairs converting into each other via pair production and inverse Compton
scattering. Under certain conditions, which should be satisfied in powerful
AGNs, the photon breeding mechanism becomes supercritical: the high-energy
photons breed exponentially until their feedback on the fluid changes its
velocity pattern. Then the system comes to a self-adjusting near-critical
steady state. Monte-Carlo simulations with the detailed treatment of particle
propagation and interactions demonstrate that a jet with the Lorentz factor
Gamma ~ 20 can radiate away up to a half of its total energy and for Gamma=40
the radiation efficiency can be up to 80 per cent. Outer layers of the jet
decelerate down to a moderate Lorentz factor 2-4, while the spine of the jet
has the final Lorentz factor in the range 10-20 independently on the initial
Gamma. Such sharp deceleration under the impact of radiation must cause a
number of interesting phenomena such as formation of internal shocks and an
early generation of turbulence.


title:
Photon breeding mechanism in relativistic jets: astrophysical
  implications

abstract:
  Photon breeding in relativistic jets involves multiplication of high-energy
photons propagating from the jet to the external environment and back with the
conversion into electron-positron pairs. The exponential growth of the energy
density of these photons is a super-critical process powered by the bulk energy
of the jet. The efficient deceleration of the jet outer layers creates a
structured jet morphology with the fast spine and slow sheath. In initially
fast and high-power jets even the spine can be decelerated efficiently leading
to very high radiative efficiencies of conversion of the jet bulk energy into
radiation. The decelerating, structured jets have angular distribution of
radiation significantly broader than that predicted by a simple blob model with
a constant Lorentz factor. This reconciles the discrepancy between the high
Doppler factors determined by the fits to the spectra of TeV blazars and the
low apparent velocities observed at VLBI scales as well as the low jet Lorentz
factors required by the observed statistics and luminosity ratio of
Fanaroff-Riley I radio galaxies and BL Lac objects. Photon breeding produces a
population of high-energy leptons in agreement with the constraints on the
electron injection function required by spectral fits of the TeV blazars.
Relativistic pairs created outside the jet and emitting gamma-rays by inverse
Compton process might explain the relatively high level of the TeV emission
from the misaligned jet in the radio galaxies. The mechanism reproduces basic
spectral features observed in blazars including the blazar sequence (shift of
the spectral peaks towards lower energies with increasing luminosity). The
mechanism is very robust and can operate in various environments characterised
by the high photon density.


title: Toward understanding rich superclusters

abstract:
  We present a morphological study of the two richest superclusters from the
2dF Galaxy Redshift Survey (SCL126, the Sloan Great Wall, and SCL9, the
Sculptor supercluster). We use Minkowski functionals, shapefinders, and galaxy
group information to study the substructure of these superclusters as formed by
different populations of galaxies. We compare the properties of grouped and
isolated galaxies in the core region and in the outskirts of superclusters. The
fourth Minkowski functional $V_3$ and the morphological signature $K_1$- $K_2$
show a crossover from low-density morphology (outskirts of supercluster) to
high-density morphology (core of supercluster) at mass fraction $m_f \approx
0.7$. The galaxy content and the morphology of the galaxy populations in
supercluster cores and outskirts is different. The core regions contain a
larger fraction of early type, red galaxies, and richer groups than the
outskirts of superclusters. In the core and outskirt regions the fine structure
of the two prominent superclusters as delineated by galaxies from different
populations also differs. Our results suggest that both local (group/cluster)
and global (supercluster) environments are important in forming galaxy
morphologies and colors (and determining the star formation activity). The
differences between the superclusters indicate that these superclusters have
different evolutional histories (Abridged).


title: The cyclic cycle complex of a surface

abstract:
  A contractible simplicial complex is constructed that parametrizes different
ways of representing a fixed one-dimensional homology class in a closed
orientable surface by isotopy classes of systems of disjoint oriented simple
closed curves. This is a variant on an earlier construction of
Bestvina-Bux-Margalit.


title: Predicting low-frequency radio fluxes of known extrasolar planets

abstract:
  Context. Close-in giant extrasolar planets (''Hot Jupiters'') are believed to
be strong emitters in the decametric radio range.
  Aims. We present the expected characteristics of the low-frequency
magnetospheric radio emission of all currently known extrasolar planets,
including the maximum emission frequency and the expected radio flux. We also
discuss the escape of exoplanetary radio emission from the vicinity of its
source, which imposes additional constraints on detectability.
  Methods. We compare the different predictions obtained with all four existing
analytical models for all currently known exoplanets. We also take care to use
realistic values for all input parameters.
  Results. The four different models for planetary radio emission lead to very
different results. The largest fluxes are found for the magnetic energy model,
followed by the CME model and the kinetic energy model (for which our results
are found to be much less optimistic than those of previous studies). The
unipolar interaction model does not predict any observable emission for the
present exoplanet census. We also give estimates for the planetary magnetic
dipole moment of all currently known extrasolar planets, which will be useful
for other studies.
  Conclusions. Our results show that observations of exoplanetary radio
emission are feasible, but that the number of promising targets is not very
high. The catalog of targets will be particularly useful for current and future
radio observation campaigns (e.g. with the VLA, GMRT, UTR-2 and with LOFAR).


title: Illuminating hadron structure by scattering light on light

abstract:
  The results of an Amplitude Analysis of the world data on integrated and
differential cross-sections on $\gamma\gamma\to\pi\pi$ are presented, following
the publication of the Belle charged pion results.


title: Topological Order in Frustrated Josephson Junction Arrays

abstract:
  We show that electrically and magnetically frustrated Josephson junction
arrays (JJAs) realize topological order with a non-trivial ground state
degeneracy on manifolds with non-trivial topology. The low-energy theory has
the same gauge dynamics of the unfrustrated JJAs but for different,
"fractional" degrees of freedom, a principle reminescent of Jain's composite
electrons in the fractional quantum Hall effect.


title:
Leptogenesis in the Exceptional Supersymmetric Standard Model: flavour
  dependent lepton asymmetries

abstract:
  We calculate flavour dependent lepton asymmetries within the $E_6$ inspired
Supersymmetric Standard Model ($\rm E_6SSM$), which has an extra $U(1)_N$
symmetry. In this model, the right-handed neutrino doesn't participate in gauge
interactions, allowing it to be used for both the see--saw mechanism and
leptogenesis. Extra Higgs, leptons and leptoquarks predicted by the E$_6$SSM
contribute to the ordinary lepton CP asymmetries induced by the decays of the
lightest right--handed neutrino (and sneutrino) and give rise to a set of extra
decay asymmetries. We find that the CP asymmetries can be relatively large,
even when the lightest right--handed neutrino is as light as $10^6 {GeV}$.


title: Universal Weak Lensing Distortion of Cosmological Correlation Functions

abstract:
  Gravitational lensing affects observed cosmological correlation functions
because observed images do not coincide with true source locations. We treat
this universal effect in a general way here, deriving a single formula that can
be used to determine to what extent this effect distorts any correlation
function. We then apply the general formula to the correlation functions of
galaxies, of the 21-cm radiation field, and of the CMB.


title: Double Categories in Mathematical Physics

abstract:
  Expansion of the categorical point of view on many areas of the mathematics
and mathematical physics will cause to deeper understanding of genuine features
of these problems. New applications of categorical methods are connected with
new additional structures on categories. One of such structures, the double
category, is considered in this article. The double category structure is
defined as generalization of the bicategory structure. It is shown that double
categories exist in the topological and ordinary quantum field theories, and
for dynamical systems with inputs and outputs. Morphisms of all these double
categories are not maps of sets.


title:
Ab initio coupled-cluster and configuration interaction calculations for
  16-O using V_UCOM

abstract:
  Using the ground-state energy of 16-O obtained with the realistic V_UCOM
interaction as a test case, we present a comprehensive comparison of different
configuration interaction (CI) and coupled-cluster (CC) methods, analyzing the
intrinsic advantages and limitations of each of the approaches. In particular,
we use the importance-truncated (IT) CI and no-core shell model (NCSM) schemes
with up to 4-particle-4-hole (4p4h) excitations as well as the size extensive
CC methods with a complete treatment of one- and two-body clusters (CCSD) and a
non-iterative treatment of connected three-body clusters via the completely
renormalized correction to the CCSD energy defining the CR-CC(2,3) approach. We
discuss the impact of the center-of-mass contaminations, the choice of the
single-particle basis, and size-extensivity on the resulting energies. When the
IT-CI and IT-NCSM methods include the 4p4h excitations and when the CC
calculations include the 1p1h, 2p2h, and 3p3h clusters, as in the CR-CC(2,3)
approach, we observe an excellent agreement among the different methodologies.
This shows that despite their individual limitations, the IT-CI, IT-NCSM, and
CC methods can provide precise and consistent ab initio nuclear structure
predictions. Furthermore, the IT-CI, IT-NCSM, and CC ground-state energy values
obtained with 16-O are in good agreement with the experimental value, proving
that the V_UCOM two-body interaction allows for a realistic description of
binding energies for heavier nuclei and that all of the methods used in this
study account for most of the relevant particle correlation effects.


title: A Possible Explanation of Anomalous Earth Flybys

abstract:
  Doppler shift observations of several spacecrafts during near Earth flybys
show an unexplained frequency shift. This shift is interpreted as an unexpected
velocity change called Earth flyby anomaly. A theory of non-privileged
reference frames is used to study the Doppler shift in such frames which are
experimentally justified by the measured dipole anisotropy of the cosmic
microwave background (CMB) in the solar system. The system in which the CMB is
isotropic defines the privileged reference frame. The calculated frequency
shift in non-privileged reference frames may give an explanation of the
anomalous Earth flybys.


title:
Taking off the square root of Nambu-Goto action and obtaining
  Filippov-Lie algebra gauge theory action

abstract:
  We propose a novel prescription to take off the square root of Nambu-Goto
action for a p-brane, which generalizes the Brink-Di Vecchia-Howe-Tucker or
also known as Polyakov method. With an arbitrary decomposition as d+n=p+1, our
resulting action is a modified d-dimensional Polyakov action which is gauged
and possesses a Nambu n-bracket squared potential. We first spell out how the
(p+1)-dimensional diffeomorphism is realized in the lower dimensional action.
Then we discuss a possible gauge fixing of it to a direct product of
$d$-dimensional diffeomorphism and n-dimensional volume preserving
diffeomorphism. We show that the latter naturally leads to a novel Filippov-Lie
n-algebra based gauge theory action in d-dimensions.


title:
Primordial perturbations and non-Gaussianities in DBI and general
  multi-field inflation

abstract:
  We study cosmological perturbations in general inflation models with multiple
scalar fields and arbitrary kinetic terms, with special emphasis on the
multi-field extension of Dirac-Born-Infeld (DBI) inflation. We compute the
second-order action governing the dynamics of linear perturbations in the most
general case. Specializing to DBI, we show that the adiabatic and entropy modes
propagate with a {\it common} effective sound speed and are thus amplified at
sound horizon crossing. In the small sound speed limit, we find that the
amplitude of the entropy modes is much higher than that of the adiabatic modes.
We also derive, in the general case, the third-order action which is useful for
studying primordial non-Gaussianities generated during inflation. In the DBI
case, we compute the dominant contributions to non-Gaussianities, which depend
on both the adiabatic and entropy modes.


title: Single crystal of superconducting SmFeAsO1-xFy grown at high pressure

abstract:
  Single crystals of SmFeAsO1-xFy of a size up to 120 micrometers have been
grown from NaCl/KCl flux at a pressure of 30 kbar and temperature of 1350-1450
C using the cubic anvil high-pressure technique. The superconducting transition
temperature of the obtained single crystals varies between 45 and 53 K.Obtained
crystals are characterized by a full diamagnetic response in low magnetic
fields and by a high critical current density in high magnetic fields.
Structural refinement has been performed on single crystal. Differential
thermal analysis investigations at 1 bar Ar pressure show decomposition of
SmFeAsO1-xFy at 1302 C.


title: Fluctuations in granular gases

abstract:
  A driven granular material, e.g. a vibrated box full of sand, is a stationary
system which may be very far from equilibrium. The standard equilibrium
statistical mechanics is therefore inadequate to describe fluctuations in such
a system. Here we present numerical and analytical results concerning energy
and injected power fluctuations. In the first part we explain how the study of
the probability density function (pdf) of the fluctuations of total energy is
related to the characterization of velocity correlations. Two different regimes
are addressed: the gas driven at the boundaries and the homogeneously driven
gas. In a granular gas, due to non-Gaussianity of the velocity pdf or lack of
homogeneity in hydrodynamics profiles, even in the absence of velocity
correlations, the fluctuations of total energy are non-trivial and may lead to
erroneous conclusions about the role of correlations. In the second part of the
chapter we take into consideration the fluctuations of injected power in driven
granular gas models. Recently, real and numerical experiments have been
interpreted as evidence that the fluctuations of power injection seem to
satisfy the Gallavotti-Cohen Fluctuation Relation. We will discuss an
alternative interpretation of such results which invalidates the
Gallavotti-Cohen symmetry. Moreover, starting from the Liouville equation and
using techniques from large deviation theory, the general validity of a
Fluctuation Relation for power injection in driven granular gases is
questioned. Finally a functional is defined using the Lebowitz-Spohn approach
for Markov processes applied to the linear inelastic Boltzmann equation
relevant to describe the motion of a tracer particle. Such a functional results
to be different from injected power and to satisfy a Fluctuation Relation.


title: Quantum Spacetime Phenomenology

abstract:
  I review the current status of phenomenological programs inspired by
quantum-spacetime research. I stress in particular the significance of results
establishing that certain data analyses provide sensitivity to effects
introduced genuinely at the Planck scale. And my main focus is on
phenomenological programs that managed to affect the directions taken by
studies of quantum-spacetime theories.


title: Chiral Unitary Dynamics of Hadrons and Hadrons in a Nuclear Medium

abstract:
  In this talk I summarize recent findings around the description of axial
vector mesons as dynamically generated states from the interaction of
pseudoscalar mesons and vector mesons, dedicating some attention to the two
$K_1(1270)$ states. Then I review the generation of open and hidden charm
scalar and axial states, and how some recent experiment supports the existence
of the new hidden charm scalar state predicted. I present recent results
showing that the low lying $1/2^+$ baryon resonances for S=-1 can be obtained
as bound states or resonances of two mesons and one baryon in coupled channels.
Then show the differences with the S=0 case, where the $N^*(1710)$ appears also
dynamically generated from the two pion one nucleon system, but the $N^*(1440)$
does not appear, indicating a more complex structure of the Roper resonance.
Finally I shall show how the state X(2175), recently discovered at BABAR and
BES, appears naturally as a resonance of the $\phi K \bar{K}$ system.


title: Succinct Greedy Graph Drawing in the Hyperbolic Plane

abstract:
  We describe an efficient method for drawing any n-vertex simple graph G in
the hyperbolic plane. Our algorithm produces greedy drawings, which support
greedy geometric routing, so that a message M between any pair of vertices may
be routed geometrically, simply by having each vertex that receives M pass it
along to any neighbor that is closer in the hyperbolic metric to the message's
eventual destination. More importantly, for networking applications, our
algorithm produces succinct drawings, in that each of the vertex positions in
one of our embeddings can be represented using O(log n) bits and the
calculation of which neighbor to send a message to may be performed efficiently
using these representations. These properties are useful, for example, for
routing in sensor networks, where storage and bandwidth are limited.


title:
The principal eigenvalue of the $\infty$-Laplacian with the Neumann
  boundary condition

abstract:
  We prove the existence of a principal eigenvalue associated to the
$\infty$-Laplacian plus lower order terms and the Neumann boundary condition in
a bounded smooth domain. As an application we get uniqueness and existence
results for the Neumann problem and a decay estimate for viscosity solutions of
the Neumann evolution problem.


title:
Luminosity and surface brightness distribution of K-band galaxies from
  the UKIDSS Large Area Survey

abstract:
  We present luminosity and surface brightness distributions of 40,111 galaxies
with K-band photometry from the United Kingdom Infrared Telescope (UKIRT)
Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS), Data Release 3 and
optical photometry from Data Release 5 of the Sloan Digital Sky Survey (SDSS).
Various features and limitations of the new UKIDSS data are examined, such as a
problem affecting Petrosian magnitudes of extended sources. Selection limits in
K- and r-band magnitude, K-band surface brightness and K-band radius are
included explicitly in the 1/Vmax estimate of the space density and luminosity
function. The bivariate brightness distribution in K-band absolute magnitude
and surface brightness is presented and found to display a clear
luminosity--surface brightness correlation that flattens at high luminosity and
broadens at low luminosity, consistent with similar analyses at optical
wavelengths. Best fitting Schechter function parameters for the K-band
luminosity function are found to be M*-5 log h=-23.19 +/- 0.04, alpha=-0.81 +/-
0.04 and phi*=(0.0166 +/- 0.0008)h^3 Mpc^{-3}, although the Schechter function
provides a poor fit to the data at high and low luminosity, while the
luminosity density in the K band is found to be j = (6.305 +/- 0.067) x 10^8
L_sun h Mpc^{-3}. However, we caution that there are various known sources of
incompleteness and uncertainty in our results. Using mass-to-light ratios
determined from the optical colours we estimate the stellar mass function,
finding good agreement with previous results. Possible improvements are
discussed that could be implemented when extending this analysis to the full
LAS.


title: A multi-agent-based approach to tax morale

abstract:
  We embed the behaviour of tax evasion into the standard two-dimensional Ising
model. In the presence of an external magnetic field, the Ising model is able
to generate the empirically observed effect of tax morale, i.e. the phenomenon
that in some countries tax evasion is either rather high or low. The external
magnetic field captures the agents' trust in governmental institutions. We also
find that tax authorities may curb tax evasion via appropriate enforcement
mechanisms. Our results are robust for the Barab\'asi-Albert and
Voronoi-Delaunay networks.


title: Hinode Observations of Magnetic Elements in Internetwork Areas

abstract:
  We use sequences of images and magnetograms from Hinode to study magnetic
elements in internetwork parts of the quiet solar photosphere. Visual
inspection shows the existence of many long-lived (several hours) structures
that interact frequently, and may migrate over distances ~7 Mm over a period of
a few hours. About a fifth of the elements have an associated bright point in
G-band or Ca II H intensity. We apply a hysteresis-based algorithm to identify
elements. The algorithm is able to track elements for about 10 min on average.
Elements intermittently drop below the detection limit, though the associated
flux apparently persists and often reappears some time later. We infer proper
motions of elements from their successive positions, and find that they obey a
Gaussian distribution with an rms of 1.57+-0.08 km/s. The apparent flows
indicate a bias of about 0.2 km/s toward the network boundary. Elements of
negative polarity show a higher bias than elements of positive polarity,
perhaps as a result of to the dominant positive polarity of the network in the
field of view, or because of increased mobility due to their smaller size. A
preference for motions in X is likely explained by higher supergranular flow in
that direction. We search for emerging bipoles by grouping elements of opposite
polarity that appear close together in space and time. We find no evidence
supporting Joy's law at arcsecond scales.


title: Quantum Trivelpiece-Gould waves in a magnetized dense plasma

abstract:
  The dispersion relation for the electrostatic waves below the electron plasma
frequency in a dense quantum plasma is derived by using the magnetohydrodynamic
model. It is shown that in the classical case the dispersion relation reduces
to the expression obtained for the well-known Trivelpiece-Gould (TG) modes.
Attention is also devoted to the case of solitary waves associated with the
nonlinear TG modes.


title:
$J/\psi$ production in pp collisions at $\sqrt{{\rm s}}$=200GeV in the
  STAR experiment

abstract:
  In this work we present the $J/\psi$ measurement in p+p collisions within the
STAR collaboration Quarkonium program. This measurements aim to be the baseline
measurement of a more comprehensive systematic study of quarkonium states
production in order to understand their in medium modification. Here we report
the total cross section and $p_T$ distribution, and find them to be consistent
with pQCD CEM predictions as well as to previous measurements at the same
center-of-mass energy.


title: Radiation Pressure Acceleration by Ultraintense Laser Pulses

abstract:
  The future applications of the short-duration, multi-MeV ion beams produced
in the interaction of high-intensity laser pulses with solid targets will
require improvements in the conversion efficiency, peak ion energy, beam
monochromaticity, and collimation. Regimes based on Radiation Pressure
Acceleration (RPA) might be the dominant ones at ultrahigh intensities and be
most suitable for specific applications. This regime may be reached already
with present-day intensities using circularly polarized (CP) pulses thanks to
the suppression of fast electron generation, so that RPA dominates over sheath
acceleration at any intensity. We present a brief review of previous work on
RPA with CP pulses and a few recent results. Parametric studies in one
dimension were performed to identify the optimal thickness of foil targets for
RPA and to study the effect of a short-scalelength preplasma. Three-dimensional
simulations showed the importance of ``flat-top'' radial intensity profiles to
minimise the rarefaction of thin targets and to address the issue of angular
momentum conservation and absorption.


title:
Warped Convolutions: A Novel Tool in the Construction of Quantum Field
  Theories

abstract:
  Recently, Grosse and Lechner introduced a novel deformation procedure for
non-interacting quantum field theories, giving rise to interesting examples of
wedge-localized quantum fields with a non-trivial scattering matrix. In the
present article we outline an extension of this procedure to the general
framework of quantum field theory by introducing the concept of warped
convolutions: given a theory, this construction provides wedge-localized
operators which commute at spacelike distances, transform covariantly under the
underlying representation of the Poincare group and admit a scattering theory.
The corresponding scattering matrix is nontrivial but breaks the Lorentz
symmetry, in spite of the covariance and wedge-locality properties of the
deformed operators.


title:
Slow relaxation, dynamic transitions and extreme value statistics in
  disordered systems

abstract:
  We show that the dynamics of simple disordered models, like the directed Trap
Model and the Random Energy Model, takes place at a coexistence point between
active and inactive dynamical phases. We relate the presence of a dynamic phase
transition in these models to the extreme value statistics of the associated
random energy landscape.


title:
Towards the smoothness of optimal maps on Riemannian submersions and
  Riemannian products (of round spheres in particular)

abstract:
  The key condition A3w of Ma, Trudinger and Wang for regularity of optimal
transportation maps is implied by the nonnegativity of a pseudo-Riemannian
curvature -- which we call cross-curvature -- induced by the transportation
cost. For the Riemannian distance squared cost, it is shown that (1)
cross-curvature nonnegativity is preserved for products of two manifolds; (2)
both A3w and cross-curvature nonnegativity are inherited by Riemannian
submersions; and (3) the $n$-dimensional round sphere satisfies cross-curvature
nonnegativity. From these results, a large new class of Riemannian manifolds
satisfying cross-curvature nonnegativity (thus A3w) is obtained, including many
whose sectional curvature is far from constant. All known obstructions to the
regularity of optimal maps are absent from these manifolds, making them a class
for which it is natural to conjecture that regularity holds. This conjecture is
confirmed for complex projective space CP^n.


title: Causal relativistic hydrodynamics for viscous fluids

abstract:
  We report on recent results from VISH2+1, a code that solves the relativistic
Israel-Stewart equations for causal viscous hydrodynamics for heavy-ion
collisions with longitudinal boost invariance. We find that even ``minimal''
shear viscosity eta/s=hbar/(4pi) leads to a large reduction of elliptic flow
compared to ideal fluid dynamics. We explore systematically the sensitivity of
this reduction to the equation of state, system size, initial conditions, and
the microscopic relaxation time in different formulations of the Israel-Stewart
equations.


title: $J/\psi$ and $\Upsilon$ measurements in STAR

abstract:
  Heavy-quarkonium states are expected to evidenciate the deconfinement of the
nuclear matter into a Quark-Gluon Plasma in heavy-ion collisions. To strive
conclusive information from quarkonium production modification in A+A
collisions, systematic measurements of the $J/\psi$ and $\Upsilon$ states in
p+p, d+Au and Au+Au collisions are necessary. To accomplish this mission the
STAR experiment has a Quarkonium program based on the development of specific
trigger setups that take advantage of the large STAR acceptance. In this work
we present the preliminary results of the $J/\psi$ and $\Upsilon$ measurement
in 200 GeV p+p and the first measurements of $\Upsilon$ in 200 GeV heavy ion
collisions.


title:
The vanishing of two-point functions for three-loop superstring
  scattering amplitudes

abstract:
  In this paper we show that the two-point function for the three-loop chiral
superstring measure ansatz proposed by Cacciatori, Dalla Piazza, and van Geemen
vanishes. Our proof uses the reformulation of ansatz in terms of even cosets,
theta functions, and specifically the theory of the $\Gamma_{00}$ linear system
on Jacobians introduced by van Geemen and van der Geer.
  At the two-loop level, where the amplitudes were computed by D'Hoker and
Phong, we give a new proof of the vanishing of the two-point function (which
was proven by them). We also discuss the possible approaches to proving the
vanishing of the two-point function for the proposed ansatz in higher genera.


title:
Spectro-microscopy of single and multi-layer graphene supported by a
  weakly interacting substrate

abstract:
  We report measurements of the electronic structure and surface morphology of
exfoliated graphene on an insulating substrate using angle-resolved
photoemission and low energy electron diffraction. Our results show that
although exfoliated graphene is microscopically corrugated, the valence band
retains a massless fermionic dispersion, with a Fermi velocity of ~10^6 m/s. We
observe a close relationship between the morphology and electronic structure,
which suggests that controlling the interaction between graphene and the
supporting substrate is essential for graphene device applications.


title: A Model of Lepton Masses from a Warped Extra Dimension

abstract:
  In order to explain the non-hierarchical neutrino mixing angles and the
absence of lepton flavor violating processes in the context of warped extra
dimensions one needs to introduce bulk flavor symmetries. We present a simple
model of lepton masses and mixings in RS models based on the A4 non-abelian
discrete symmetry. The virtues of this choice are: (i) the natural appearance
of the tri-bimaximal mixing pattern; (ii) the complete absence of tree-level
flavor violations in the neutral sector; (iii) the absence of flavor gauge
bosons; (iv) the hierarchies in the charged lepton masses are explained via
wave-function overlaps. We present the minimal field content and symmetry
breaking pattern necessary to obtain a successful model of this type. The
bounds from electroweak precision measurements allow the KK mass scale to be as
low as 3 TeV. Tree-level lepton flavor violation is absent in this model, while
the loop induced mu -> e gamma branching fraction is safely below the
experimental bound.


title: The growth exponent for planar loop-erased random walk

abstract:
  We give a new proof of a result of Kenyon that the growth exponent for
loop-erased random walks in two dimensions is 5/4. The proof uses the
convergence of LERW to Schramm-Loewner evolution with parameter 2, and is valid
for irreducible bounded symmetric random walks on any two-dimensional discrete
lattice.


title:
Universal upper bound on the energy of a parton escaping from the
  strongly coupled quark-gluon matter

abstract:
  It has been shown through the AdS/CFT correspondence that the energy loss of
a fast quark in a strongly coupled ${\cal N}=4$ SUSY Yang--Mills matter in the
large N limit is given by the classical Lienard formula. I demonstrate that
under quite natural assumptions about the dynamics of heavy ion collisions this
leads to a universal (i.e. independent of the initial parton energy, but
dependent on flavor and centrality) upper bound on the energy of the partons
escaping from the plasma. This bound is a Yang--Mills analog of the Pomeranchuk
bound in classical electrodynamics, where it is a consequence of radiation in a
strong external field acting on a relativistic charge. Since as a result the
massive constituent partons are slowed down to a velocity v < c, the angular
distribution of the emitted radiation exhibits a broad "dead cone". If the
properties of conformal and QCD matter at strong coupling are qualitatively
similar, the existence of this universal upper bound would have dramatic
implications for heavy ion experiments.


title:
Inconsistencies of a purported probability current in the
  Duffin-Kemmer-Petiau theory

abstract:
  The Duffin-Kemmer-Petiau (DKP) equation with a square step potential is used
in a simple way with polymorphic purposes. It proves adequate to refuse a
proposed new current that is currently interpreted as a probability current,to
show that the Klein paradox does exist in the DKP theory and to revise other
minor misconceptions diffused in the literature.


title:
"Short-term time prediction" of large EQs by the use of "Large Scale
  Piezoelectricity" generated by the focal areas loaded with excess stress load

abstract:
  In this work, it is demonstrated that the Earth's preseismic electric field,
which is registered by a pair of electrodes in contact to the ground surface at
certain distance from the epicentral area, corresponds to the gradient of the
total field generated in the focal area as a function of time and distance from
it. The original form of the generated preseismic field follows closely the
theoretical piezoelectric potential form. The later is obtained after
integration in time of the original registered potential grad data values.
Consequently, the time of occurrence of the imminent earthquake (collapsing of
the rock formation) is estimated by the classical laws of rock fracturing based
on theoretical Rock Mechanics. The methodology has been tested on the grad
potential data, registered in Greece, before four large EQs which took place in
the regional area as follows: Izmit, Turkey EQ (M = 7.8R, 17th August, 1999),
Milos, Greece EQ (M = 5.6R, 21st May, 2002), Kythira Greece EQ (M = 6.9R, 8th
January, 2006) and Methoni, Greece EQ (M = 6.7R, 14th February, 2008). The
obtained results prove the validity of the postulated methodology.


title:
Free Analysis Questions II: The Grassmannian Completion and The Series
  Expansions at the Origin

abstract:
  The fully matricial generalization in part I, of the difference quotient
derivation on holomorphic functions, in which ${\mathbb C}$ is replaced by a
Banach algebra $B$, is extended from the affine case to a Grassmannian
completion. The infinitesimal bialgebra duality, the duality transform
generalizing the Stieltjes transform and the spectral theory with non-commuting
scalars all extend to this completion. The series expansions of fully matricial
analytic functions are characterized, providing a new way to generate fully
matricial functions.


title: Density fluctuations for a zero-range process on the percolation cluster

abstract:
  We prove that the density fluctuations for a zero-range process evolving on
the supercritical percolation cluster are given by a generalized
Ornstein-Uhlenbeck process in the space of distributions $\mc S'(\bb R^d)$.


title: M2-Brane Superalgebra from Bagger-Lambert Theory

abstract:
  It is known that the M2-brane worldvolume superalgebra includes two p-form
central charges that encode the M-theory intersections involving M2-branes. In
this paper we show by explicit computation that the Bagger-Lambert Lagrangian
realizes the M2-brane superalgebra, including also the central extensions.
Solitons of the Bagger-Lambert theory, that are interpreted as worldvolume
realizations of intersecting branes, are shown to saturate a BPS-bound given in
terms of the corresponding central charge.


title: Spatial distribution of luminous X-ray binaries in spiral galaxies

abstract:
  We have modelled the spatial distribution of luminous X-ray binaries (XRBs)
in spiral galaxies that are like the Milky Way using an evolutionary population
synthesis code. In agreement with previous theoretical expectations and
observations, we find that both high- and low-mass XRBs show clear
concentrations towards the galactic plane and bulge.We also compare XRB
distributions under the galactic potential with a dark matter halo and the
modified Newtonian dynamics potential, and we suggest that the difference may
serve as potential evidence to discriminate between these two types of model.


title:
Coarse graining, fractional moments and the critical slope of random
  copolymers

abstract:
  For a much-studied model of random copolymer at a selective interface we
prove that the slope of the critical curve in the weak-disorder limit is
strictly smaller than 1, which is the value given by the annealed inequality.
The proof is based on a coarse-graining procedure, combined with upper bounds
on the fractional moments of the partition function.


title: Magnetic properties of dense holographic QCD

abstract:
  We investigate the Sakai-Sugimoto model at nonzero baryon chemical potential
in a background magnetic field both in the confined phase and in the deconfined
phase with restored chiral symmetry. In this case the 8-brane Chern-Simons term
becomes important. In the confined phase it generates a gradient of the
pseudo-scalar "pion", which carries a non-vanishing baryon charge. Above a
critical value of the chemical potential there is a second order phase
transition to a mixed phase which includes also ordinary baryonic matter.
However, at fixed baryon charge density the matter is purely "pion"-gradient
above a critical magnetic field. In the deconfined chiral-symmetric phase at
nonzero chemical potential the magnetic field induces an axial current. We also
compute the magnetization of the baryonic matter and find that it is
paramagnetic in all three phases but with nonlinear behavior at large magnetic
field.


title: Magnetized baryonic matter in holographic QCD

abstract:
  We investigate the properties of the Sakai-Sugimoto model at finite magnetic
field and baryon chemical potentials. We show that in a finite magnetic field,
there exists a spatially homogeneous configuration carrying finite baryon
number density. At low magnetic field and baryon chemical potential the
equation of state of the matter coincides with that obtained from the chiral
perturbation theory Lagrangian with an anomalous term. We discuss the behavior
of the system at larger magnetic fields.


title: Approximate quantum cloaking and almost trapped states

abstract:
  We describe families of potentials which act as approximate cloaks for matter
waves, i.e., for solutions of the time-independent Schr\"odinger equation at
energy $E$, with applications to the design of ion traps. These are derived
from perfect cloaks for the conductivity and Helmholtz equations, by a
procedure we refer to as isotropic transformation optics. If $W$ is a potential
which is surrounded by a sequence $\{V_n^E\}_{n=1}^\infty$ of approximate
cloaks, then for generic $E$, asymptotically in $n$ (i) $W$ is both
undetectable and unaltered by matter waves originating externally to the cloak;
and (ii) the combined potential $W+V_n^E$ does not perturb waves outside the
cloak. On the other hand, for $E$ near a discrete set of energies, cloaking
{\it per se} fails and the approximate cloaks support wave functions
concentrated, or {\it almost trapped}, inside the cloaked region and negligible
outside. Applications include ion traps, almost invisible to matter waves or
customizable to support almost trapped states of arbitrary multiplicity.
Possible uses include simulation of abstract quantum systems, magnetically
tunable quantum beam switches, and illusions of singular magnetic fields.


title:
Radiative corrections to the mass of the Kink: a small modification due
  to the different renormalization procedure

abstract:
  We compute of the lowest order quantum radiative correction to the mass of
the kink in $\phi^4$ theory in 1+1 dimensions using an alternative
renormalization procedure which has been introduced earlier. We use the
standard mode number cutoff in conjunction with the above program. Our results
show a small correction to the previously reported values.[The paper has been
withdraw by the authors because a new version is been written to better
emphasize on renormalization in problems with nontrivial background. The new
version has been submitted by our new co-author (arXiv:1205.2775).]


title:
Toward a Minimum Branching Fraction for Dark Matter Annihilation into
  Electromagnetic Final States

abstract:
  Observational limits on the high-energy neutrino background have been used to
place general constraints on dark matter that annihilates only into standard
model particles. Dark matter particles that annihilate into neutrinos will also
inevitably branch into electromagnetic final states through higher-order tree
and loop diagrams that give rise to charged leptons, and these charged
particles can transfer their energy into photons via synchrotron radiation or
inverse Compton scattering. In the context of effective field theory, we
calculate the loop-induced branching ratio to charged leptons and show that it
is generally quite large, typically >1%, when the scale of the dark matter mass
exceeds the electroweak scale, M_W. For a branching fraction >3%, the
synchrotron radiation bounds on dark matter annihilation are currently stronger
than the corresponding neutrino bounds in the interesting mass range from 100
GeV to 1 TeV. For dark matter masses below M_W, our work provides a plausible
framework for the construction of a model for "neutrinos only" dark matter
annihilations.


title: Shock Breakout Emission from a Type Ib/c Supernova: XRT 080109/SN 2008D

abstract:
  The X-ray flash 080109, associated with SN 2008D, can be attributed to the
shock breakout emission from a normal Type Ib/c supernova. If the observed
emission is interpreted as blackbody emission, the temperature and radiated
energy are close to expectations, considering that scattering dominates
absorption processes so that spectrum formation occurs deep within the
photosphere. The X-ray emission observed at ~10 days is attributed to inverse
Compton scattering of photospheric photons with relativistic electrons produced
in the interaction of the supernova with the progenitor wind. A simple model
for the optical/ultraviolet emission from shock breakout is developed and
applied to SN 1987A, SN 1999ex, SN 2008D, and SN 2006aj, all of which have
optical emission observed at t~1 day. The emission from the first three can
plausibly be attributed to shock breakout emission. The photospheric
temperature is most sensitive to the radius of the progenitor star core and the
radii in these cases are in line with expectations from stellar evolution. The
early optical/ultraviolet observations of SN 2006aj cannot be accommodated by a
shock breakout model in a straightforward way.


title:
A Flat Photoionization Rate at 2<z<4.2: Evidence for a Stellar-Dominated
  UV Background and Against a Decline of Cosmic Star Formation Beyond z~3

abstract:
  We investigate the implications of our measurement of the Lyman-alpha forest
opacity at redshifts 2<z<4.2 from a sample of 86 high-resolution quasar spectra
for the evolution of the cosmic ultraviolet luminosity density and its sources.
The derived hydrogen photoionization rate is remarkably flat over this redshift
range, implying an increasing comoving ionizing emissivity with redshift.
Because the quasar luminosity function is strongly peaked near z~2,
star-forming galaxies likely dominate the ionizing emissivity at z>~3. Our
measurement argues against a star formation rate density declining beyond z~3,
in contrast with existing state-of-the-art determinations of the cosmic star
formation history from direct galaxy counts. Stellar emission from galaxies
therefore likely reionized the Universe.


title: Sasakian Geometry: The Recent Work of Krzysztof Galicki

abstract:
  This is a mainly expository article honoring my recently deceased friend and
collaborator Krzysztof Galicki who died after a tragic hiking accident. I give
a review of our recent work in Sasakian geometry. A few new results are also
presented.


title:
The Nature of UCDs: Internal Dynamics from an Expanded Sample and
  Homogeneous Database

abstract:
  We have obtained high-resolution spectra of 23 ultra-compact dwarf galaxies
(UCDs) in the Fornax cluster with -10.4>M_V>-13.5 mag (10^6<M/M_*<10^8), using
FLAMES/Giraffe at the VLT. This is the largest homogeneous data set of UCD
internal dynamics assembled to date. We derive dynamical M/L ratios for 15 UCDs
covered by HST imaging. In the M_V-sigma plane, UCDs with M_V<-12 mag are
consistent with the extrapolated Faber-Jackson relation for luminous
ellipticals, while fainter UCDs are closer to the extrapolated globular cluster
(GC) relation. At a given metallicity, Fornax UCDs have on average 30-40% lower
M/L ratios than Virgo UCDs, suggesting possible differences in age or dark
matter content between Fornax and Virgo UCDs. For our sample of Fornax UCDs we
find no significant correlation between M/L ratio and mass. We combine our data
with available M/L ratio measurements of compact stellar systems with
10^4<M/M_*<10^8, and normalise all M/L estimates to solar metallicity. We find
that UCDs (M > 2*10^6 M_*) have M/L ratios twice as large as GCs (M < 2*10^6
M_*). We show that stellar population models tend to under-predict dynamical
M/L ratios of UCDs and over-predict those of GCs. Considering the scaling
relations of stellar spheroids, UCDs align well along the 'Fundamental
Manifold', constituting the small-scale end of the galaxy sequence. The
alignment for UCDs is especially clear for r_e >~ 7 pc, which corresponds to
dynamical relaxation times that exceed a Hubble time. In contrast, GCs exhibit
a broader scatter and do not appear to align along the manifold. We argue that
UCDs are the smallest dynamically un-relaxed stellar systems, with M > 2*10^6
M_* and 7<r_e<100 pc. Future studies should aim at explaining the elevated M/L
ratios of UCDs and the environmental dependence of their properties.


title: Large-scale dynamos in turbulent convection with shear

abstract:
  (abridged) Aims: Three-dimensional numerical simulations of penetrative
compressible convection with uniform horizontal shear are used to study dynamo
action and the generation of large-scale magnetic fields. Methods: We consider
cases where the magnetic Reynolds number is either marginal or moderately
supercritical with respect to small-scale dynamo action in the absence of shear
and rotation. The effects of magnetic helicity fluxes are studied by comparing
results for the magnetic field with open and closed boundaries. Results:
Without shear no large-scale dynamos are found even if the ingredients
necessary for the alpha-effect (rotation and stratification) are present in the
system. When uniform horizontal shear is added, a large-scale magnetic field
develops, provided the boundaries are open. In this case the mean magnetic
field contains a significant fraction of the total field. For those runs where
the magnetic Reynolds number is between 60 and 250, small-scale dynamo is
expected to be excited, but the field distribution is found to be similar to
cases with smaller magnetic Reynolds number where the small-scale dynamo is not
excited. In the case of closed (perfectly conducting) boundaries, magnetic
helicity fluxes are suppressed and no large-scale fields are found. Similarly,
poor large-scale field development is seen when vertical shear is used in
combination with periodic boundary conditions in the horizontal directions. If,
however, open (normal-field) boundary conditions are used in the x-direction, a
large-scale field develops. These results support the notion that shear not
only helps to generate the field, but it also plays a crucial role in driving
magnetic helicity fluxes out of the system along the isocontours of shear,
thereby allowing efficient dynamo action.


title:
RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster
  and its Brightest Galaxy

abstract:
  Using deep Chandra and optical spectroscopic observations, we investigate an
intriguing, young massive group, RXJ1648.7+6109, at z=0.376, and we combine
these observations with previous measurements to fit the scaling relations of
intermediate-redshift groups and poor clusters. RXJ1648 appears to be in an
early stage of formation; while it follows X-ray scaling relations, its X-ray
emission is highly elongated and it lacks a central, dominant BCG. Instead,
RXJ1648 contains a central string of seven bright galaxies, which have a
smaller velocity dispersion, are on average brighter, and have less star
formation (lower EW([OII]) and EW(H_delta)) than other group galaxies. The 4-5
brightest galaxies in this string should sink to the center and merge through
dynamical friction by z=0, forming a BCG consistent with a system of RXJ1648's
mass even if 5-50% of the light is lost to an intracluster light component
(ICL). The L_X-T_X relation for intermediate-redshift groups/poor clusters is
very similar to the low-redshift cluster relation and consistent with the
low-redshift group relation. In contrast, the L_X-sigma_v and sigma_v-T_X
relations reveal that intermediate-redshift groups/poor clusters have
significantly lower velocity dispersions for their X-ray properties compared to
low-redshift systems, however the intermediate-redshift relations are currently
limited to a small range in luminosity.


title: A Hemispherical Power Asymmetry from Inflation

abstract:
  Measurements of CMB temperature fluctuations by the Wilkinson Microwave
Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of
the sky differs from the amplitude in the other half. We show that such an
asymmetry cannot be generated during single-field slow-roll inflation without
violating constraints to the homogeneity of the Universe. In contrast, a
multi-field inflationary theory, the curvaton model, can produce this power
asymmetry without violating the homogeneity constraint. The mechanism requires
the introduction of a large-amplitude superhorizon perturbation to the curvaton
field, possibly a pre-inflationary remnant or a superhorizon curvaton-web
structure. The model makes several predictions, including non-Gaussianity and
modifications to the inflationary consistency relation, that will be tested
with forthcoming CMB experiments.


title: Massloss of galaxies due to a UV-background

abstract:
  We perform cosmological hydrodynamic simulations to determine to what extent
galaxies lose their gas due to photoheating from an ionizing background. We
find that the characteristic mass at which haloes on average have lost half of
their baryons is Mc ~ 6.5 x 10^9 Msun/h at z = 0, which corresponds to a
circular velocity of 25 km/s. This is significantly lower than the filtering
mass obtained by the linear theory, which is often used in semianalytical
models of galaxy formation. We demonstrate it is the gas temperature at the
virial radius which determines whether a halo can accrete gas. A simple model
that follows the merger history of the dark matter progenitors, and where gas
accretion is not allowed when this temperature is higher than the virial
temperature of the halo, reproduces the results from the simulation remarkably
well. This model can be applied to any reionization history, and is easy to
incorporate in semianalytical models.


title:
Near zero modes in condensate phases of the Dirac theory on the
  honeycomb lattice

abstract:
  We investigate a number of fermionic condensate phases on the honeycomb
lattice, to determine whether topological defects (vortices and edges) in these
phases can support bound states with zero energy. We argue that topological
zero modes bound to vortices and at edges are not only connected, but should in
fact be \emph{identified}. Recently, it has been shown that the simplest s-wave
superconducting state for the Dirac fermion approximation of the honeycomb
lattice at precisely half filling, supports zero modes inside the cores of
vortices (P. Ghaemi and F. Wilczek, 2007). We find that within the continuum
Dirac theory the zero modes are not unique neither to this phase, nor to half
filling. In addition, we find the \emph{exact} wavefunctions for vortex bound
zero modes, as well as the complete edge state spectrum of the phases we
discuss. The zero modes in all the phases we examine have even-numbered
degeneracy, and as such pairs of any Majorana modes are simply equivalent to
one ordinary fermion. As a result, contrary to bound state zero modes in $p_x+i
p_y$ superconductors, vortices here do \emph{not} exhibit non-Abelian exchange
statistics. The zero modes in the pure Dirac theory are seemingly topologically
protected by the effective low energy symmetry of the theory, yet on the
original honeycomb lattice model these zero modes are split, by explicit
breaking of the effective low energy symmetry.


title:
An efficient phase-shifting scheme for bolometric additive
  interferometry

abstract:
  Context: Most upcoming CMB polarization experiments will use direct imaging
to search for the primordial gravitational waves through the B-modes.
Bolometric interferometry is an appealing alternative to direct imaging that
combines the advantages of interferometry in terms of systematic effects
handling and those of bolometric detectors in terms of sensitivity. Aims: We
calculate the signal from a bolometric interferometer in order to investigate
its sensitivity to the Stokes parameters paying particular attention to the
choice of the phase-shifting scheme applied to the input channels in order to
modulate the signal. Methods: The signal is expressed as a linear combination
of the Stokes parameter visibilities whose coefficients are functions of the
phase-shifts. Results: We show that the signal to noise ratio on the
reconstructed visibilities can be maximized provided the fact that the
phase-shifting scheme is chosen in a particular way called coherent summation
of equivalent baselines. As a result, a bolometric interferometer is
competitive with an imager having the same number of horns, but only if the
coherent summation of equivalent baselines is performed. We confirm our
calculations using a Monte-Carlo simulation. We also discuss the impact of the
uncertainties on the relative calibration between bolometers and propose a way
to avoid this systematic effect.


title: New Proofs of the Green-Tao-Ziegler Dense Model Theorem: An Exposition

abstract:
  Green, Tao and Ziegler prove ``Dense Model Theorems'' of the following form:
if R is a (possibly very sparse) pseudorandom subset of set X, and D is a dense
subset of R, then D may be modeled by a set M whose density inside X is
approximately the same as the density of D in R. More generally, they show that
a function that is majorized by a pseudorandom measure can be written as a sum
of a bounded function having the same expectation plus a function that is
``indistinguishable from zero.'' This theorem plays a key role in the proof of
the Green-Tao Theorem that the primes contain arbitrarily long arithmetic
progressions.
  In this note, we present a new proof of the Green-Tao-Ziegler Dense Model
Theorem, which was discovered independently by ourselves and Gowers. We refer
to our full paper for variants of the result with connections and applications
to computational complexity theory, and to Gowers' paper for applications of
the proof technique to ``decomposition, ``structure,'' and ``transference''
theorems in arithmetic and extremal combinatorics (as well as a broader survey
of such theorems).


title:
An Entropy Threshold for Strong H-alpha and Radio Emission in the Cores
  of Galaxy Clusters

abstract:
  Our Chandra X-ray Observatory archival study of intracluster entropy in a
sample of 222 galaxy clusters shows that H-alpha and radio emission from the
brightest cluster galaxy are much more pronounced when the cluster's core gas
entropy is < 30 keV cm^2. The prevalence of H-alpha emission below this
threshold indicates that it marks a dichotomy between clusters that can harbor
multiphase gas and star formation in their cores and those that cannot. The
fact that strong central radio emission also appears below this boundary
suggests that AGN feedback turns on when the intracluster medium starts to
condense, strengthening the case for AGN feedback as the mechanism that limits
star formation in the Universe's most luminous galaxies.


title: Fault-Tolerant Computing With Biased-Noise Superconducting Qubits

abstract:
  We present a universal scheme of pulsed operations for the IBM
oscillator-stabilized flux qubit comprising the CPHASE gate, single-qubit
preparations and measurements. Based on numerical simulations, we argue that
the error rates for these operations can be as low as about .5% and that noise
is highly biased, with phase errors being stronger than all other types of
errors by a factor of nearly 10^3. In contrast, the design of a CNOT gate for
this system with an error rate of less than about 1.2% seems extremely
challenging. We propose a special encoding which exploits the noise bias
allowing us to implement a logical CNOT gate where phase errors and all other
types of errors have nearly balanced rates of about .4%. Our results illustrate
how the design of an encoding scheme can be adjusted and optimized according to
the available physical operations and the particular noise characteristics of
experimental devices.


title:
Conduction and the Star-Formation Threshold in Brightest Cluster
  Galaxies

abstract:
  Current models of galaxy evolution suggest that feedback from active galactic
nuclei is needed to explain the high-luminosity cutoff in the galaxy luminosity
function. Exactly how an AGN outflow couples with the ambient medium and
suppresses star formation remains poorly understood. However, we have recently
uncovered an important clue to how that coupling might work. Observations of
H-alpha emission and blue light from the universe's most luminous galaxies,
which occupy the centers of galaxy clusters, show that star formation happens
only if the minimum specific entropy of the intracluster gas is less than 30
keV cm^2. Here we suggest that this threshold for star formation is set by the
physics of electron thermal conduction, implying that conduction is critical
for channeling AGN energy input toward incipient star-forming regions and
limiting the progress of star formation.