title:
High yield production of graphene by liquid phase exfoliation of
  graphite

abstract:
  Graphene is at the centre of nanotechnology research. In order to fully
exploit its outstanding properties, a mass production method is necessary. Two
main routes are possible: large-scale growth or large-scale exfoliation. Here,
we demonstrate graphene dispersions with concentrations up to ~0.01 mg/ml by
dispersion and exfoliation of graphite in organic solvents such as
N-methyl-pyrrolidone. This occurs because the energy required to exfoliate
graphene is balanced by the solvent-graphene interaction for solvents whose
surface energy matches that of graphene. We confirm the presence of individual
graphene sheets with yields of up to 12% by mass, using absorption
spectroscopy, transmission electron microscopy and electron diffraction. The
absence of defects or oxides is confirmed by X-ray photoelectron, infra-red and
Raman spectroscopies. We can produce conductive, semi-transparent films and
conductive composites. Solution processing of graphene opens up a whole range
of potential large-scale applications from device or sensor fabrication to
liquid phase chemistry.


title:
The long-term X-ray variability properties of AGN in the Lockman Hole
  region

abstract:
  We present the results from a detailed X-ray variability analysis of 66 AGN
in the Lockman Hole, which have optical spectroscopic identifications. We
compare, quantitatively, their variability properties with the properties of
local AGN, and we study the "variability-luminosity" relation as a function of
redshift, and the "variability-redshift" relation in two luminosity bins. We
use archival data from the last 10 XMM observations of the Lockman Hole field
to extract light curves in the rest frame, 2-10 keV band. We use the
"normalized excess variance" to quantify the variability amplitude. Using the
latest results regarding the AGN power spectral shape and its dependence on
black hole mass and accretion rate, we are able to compute model
"variability-luminosity" curves, which we compare with the relations we
observe. When we consider all the sources in our sample, we find that their
variability amplitude decreases with increasing redshift and luminosity. These
global anti-correlations are less pronounced when we split the objects in
various luminosity and redshift bins. We do not find a significant correlation
between variability amplitude and spectral slope. The "variability-luminosity"
relation that we detect has a larger amplitude when compared to that of local
AGN. We also find that, at a given luminosity, the variability amplitude
increases with redshift up to z~1, and then stays roughly constant. Our results
imply that the AGN X-ray mechanism operates in the same way at all redshifts.
Among objects with the same luminosity in our sample, the black hole mass
decreases and the accretion rate increases with larger redshift.


title: On the Hochschild homology of elliptic Sklyanin algebras

abstract:
  In this paper, we compute the Hochschild homology of elliptic Sklyanin
algebras. These algebras are deformations of polynomial algebra with a Poisson
bracket called the Sklyanin Poisson bracket.


title: Multi-photon entanglement and interferometry

abstract:
  Multi-photon interference reveals strictly non-classical phenomena. Its
applications range from fundamental tests of quantum mechanics to photonic
quantum information processing, where a significant fraction of key experiments
achieved so far comes from multi-photon state manipulation. We review the
progress, both theoretical and experimental, of this rapidly advancing
research. The emphasis is given to the creation of photonic entanglement of
various forms, tests of the completeness of quantum mechanics (in particular,
violations of local realism), quantum information protocols for quantum
communication (e.g., quantum teleportation, entanglement purification and
quantum repeater), and quantum computation with linear optics. We shall limit
the scope of our review to "few photon" phenomena involving measurements of
discrete observables.


title: Network QoS Management in Cyber-Physical Systems

abstract:
  Technical advances in ubiquitous sensing, embedded computing, and wireless
communication are leading to a new generation of engineered systems called
cyber-physical systems (CPS). CPS promises to transform the way we interact
with the physical world just as the Internet transformed how we interact with
one another. Before this vision becomes a reality, however, a large number of
challenges have to be addressed. Network quality of service (QoS) management in
this new realm is among those issues that deserve extensive research efforts.
It is envisioned that wireless sensor/actuator networks (WSANs) will play an
essential role in CPS. This paper examines the main characteristics of WSANs
and the requirements of QoS provisioning in the context of cyber-physical
computing. Several research topics and challenges are identified. As a sample
solution, a feedback scheduling framework is proposed to tackle some of the
identified challenges. A simple example is also presented that illustrates the
effectiveness of the proposed solution.


title: LCSH, SKOS and Linked Data

abstract:
  A technique for converting Library of Congress Subject Headings MARCXML to
Simple Knowledge Organization System (SKOS) RDF is described. Strengths of the
SKOS vocabulary are highlighted, as well as possible points for extension, and
the integration of other semantic web vocabularies such as Dublin Core. An
application for making the vocabulary available as linked-data on the Web is
also described.


title: Energy functional for the three-level Lipkin model

abstract:
  We compute the energy functional of a three-level Lipkin model via a
Legrendre transform and compare exact numerical results with analytical
solutions obtained from the random phase approximation (RPA). Except for the
region of the phase transition, the RPA solutions perform very well. We also
study the case of three non-degenerate levels and again find that the RPA
solution agrees well with the exact numerical result. For this case, the
analytical results give us insight into the form of the energy functional in
the presence of symmetry-breaking one-body potentials.


title: Magnetic dipole induced guided vortex motion

abstract:
  We present evidence of magnetically controlled guided vortex motion in a
hybrid superconductor/ferromagnet nanosystem consisting of an Al film on top of
a square array of permalloy square rings. When the rings are magnetized with an
in-plane external field H, an array of point-like dipoles with moments
antiparallel to H, is formed. The resulting magnetic template generates a
strongly anisotropic pinning potential landscape for vortices in the
superconducting layer. Transport measurements show that this anisotropy is able
to confine the flux motion along the high symmetry axes of the square lattice
of dipoles. This guided vortex motion can be either re-routed by 90 degrees by
simply changing the dipole orientation or even strongly suppressed by inducing
a flux-closure magnetic state with very low stray fields in the rings.


title: Discrete differential forms for cosmological space-times

abstract:
  In this article we describe applications of the numerical method of discrete
differential forms in computational GR. In particular we consider the initial
value problem for vacuum space-times that admit plane gravitational waves. As
described in an earlier paper the discrete differential form approach can
provide accurate results in spherically symmetric space-times. Moreover it is
manifestly coordinate independent.
  Here we use the polarised Gowdy solution as a testbed for two numerical
schemes. One scheme reproduces that solution very well, in particular it is
stable for a comparatively long time and converges quadratically.


title: Constructive physics

abstract:
  Discussion of the necessity to use the constructive mathematics as the
formalism of quantum theory for systems with many particles.


title: Diagonal invariants and the refined multimahonian distribution

abstract:
  Combinatorial aspects of multivariate diagonal invariants of the symmetric
group are studied. As a consequence it is proved the existence of a
multivariate extension of the classical Robinson-Schensted correspondence.
Further byproduct are a pure combinatorial algorithm to describe the
irreducible decomposition of the tensor product of two irreducible
representations of the symmetric group, and new symmetry results on permutation
enumeration with respect to descent sets.


title:
HiZELS: a high redshift survey of H-alpha emitters. I: the cosmic
  star-formation rate and clustering at z=2.23

abstract:
  We present results from a near-infrared narrow-band survey of emission-line
galaxies at z=2.23, using the Wide Field Camera on the United Kingdom Infrared
Telescope. The H2S1 narrow-band filter (lambda_c=2.121um) we employ selects the
H-alpha emission line redshifted to z=2.23, and is thus suitable for selecting
'typical' star forming galaxies and active galactic nuclei at this epoch. The
pilot study was undertaken in the well studied Cosmological Evolution Survey
field (COSMOS) and is already the largest near-infrared narrow-band survey at
this depth, with a line flux limit of F(H-alpha)~10^-16 erg/s/cm^2 over 0.60
square degrees, probing ~220x10^3 Mpc^3 (co-moving) down to a limiting star
formation rate of 30 M_sun/yr (3sigma). In this paper we present the results
from our pilot survey and evaluate the H-alpha luminosity function and estimate
the clustering properties of H-alpha emitters at z=2.23 from 55 detected
galaxies. The integrated luminosity function is used to estimate the volume
averaged star formation rate at z=2.23: SFRD = 0.17^{+0.16}_{-0.09}
M_sun/yr/Mpc^3 for L(H-alpha) > 10^42 erg/s. For the first time, we use the
H-alpha star-formation tracer to reliably constrain SFRD out to z=2.23
demonstrating the rapid increase in SRFD out to this redshift as well as
confirming the flattening in SFRD between z~1-2. In addition to the luminosity
distribution, we analyse the clustering properties of these galaxies. Using the
2-point angular correlation function, we estimate a real space correlation
length of r_0= 4.2^{+0.4}_{-0.2} h^-1 Mpc. In comparison to models of
clustering which take into account bias evolution, we estimate that these
galaxies are hosted by dark matter halos of mass M_halo ~ 10^12 M_sun
consistent with the progenitors of the Milky Way.


title: Segregation induced by inelasticity in a vibrofluidized granular mixture

abstract:
  We investigate the segregation of a dense binary mixture of granular
particles that only differ in their restitution coefficient. The mixture is
vertically vibrated in the presence of gravity. We find a partial segregation
of the species, where most dissipative particles submerge in the less
dissipative ones. The segregation occurs even if one type of the particles is
elastic. In order to have a complete description of the system, we study the
structure of the fluid at microscopic scale (few particle diameters). The
density and temperature pair distribution functions show strong enhancements
respect the equilibrium ones at the same density. In particular, there is an
increase in the probability that the more inelastic particles group together in
pairs (microsegregation). Microscopically the segregation is buoyancy driven,
by the appearance of a dense and cold region around the more inelastic
particles.


title: Recent Results from MiniBooNE

abstract:
  Recent results from MiniBooNE are described. These include neutrino
oscillation results, low energy anomaly, and neutrino/antineutrino cross
sections.


title:
Fusion d'images: application au contr\^ole de la distribution des
  biopsies prostatiques

abstract:
  This paper is about the application of a 3D ultrasound data fusion technique
to the 3D reconstruction of prostate biopies in a reference volume. The method
is introduced and its evaluation on a series of data coming from 15 patients is
described.


title: Cohomology algebra of orbit spaces of free involutions on lens spaces

abstract:
  Let $G$ be a group acting continuously on a space $X$ and let $X/G$ be its
orbit space. Determining the topological or cohomological type of the orbit
space $X/G$ is a classical problem in the theory of transformation groups. In
this paper, we consider this problem for cohomology lens spaces. Let $X$ be a
finitistic space having the mod 2 cohomology algebra of the lens space
$L_p^{2m-1}(q_1,...,q_m)$. Then we classify completely the possible mod 2
cohomology algebra of orbit spaces of arbitrary free involutions on $X$. We
also give examples of spaces realizing the possible cohomology algebras. In the
end, we give an application of our results to non-existence of
$\mathbb{Z}_2$-equivariant map $\mathbb{S}^n \to X$.


title: Towards QCD thermodynamics using exact chiral symmetry on lattice

abstract:
  The thermodynamics of massless ideal gas of overlap quarks has been
investigated numerically for both zero and nonzero baryon chemical potential
$\mu$. While the parameter M has been shown to be irrelevant in the continuum
limit, it is shown numerically that the continuum limit can be reached with
relatively coarser lattices for certain range of M. Numerical limitation of the
existing method of introduction of chemical potential in the overlap formalism
is discussed. We have also studied the energy density of free domain wall
fermions in the absence of $\mu$ and estimated the extent of lattice in the
fifth dimension $L_5$ for which the overlap results are recovered.
Interestingly, this value of $L_5$ is also minimum for the same range of M
found in the overlap case.


title: Diophantine approximation with arithmetic functions, I

abstract:
  We prove a strong simultaneous Diophantine approximation theorem for values
of additive and multiplicative functions provided that the functions have
certain regularity on the primes.


title: Structural Transitions and Soft Modes in Frustrated DNA Crystals

abstract:
  Relying on symmetry considerations appropriate for helical biopolymers such
as DNA and filamentous actin, we argue that crystalline packings of mutually
repulsive helical macromolecules fall principally into two categories:
unfrustrated (hexagonal) and frustrated (rhombohedral). For both cases, we
construct the Landau-Ginzburg free energy for the 2D columnar-hexagonal to 3D
crystalline phase transition, including the coupling between molecular
displacements {\it along} biopolymer backbone to displacements in the plane of
hexagonal order. We focus on the distinct elastic properties that emerge upon
crystallization of helical arrays due to this coupling. Specifically, we
demonstrate that frustrated states universally exhibit a highly anisotropic
in-plane elastic response, characterized by an especially soft compliance to
simple-shear deformations and a comparatively large resistance to those
deformations that carry the array from the low- to high-density crystalline
states of DNA.


title: Natural Topologies on Colombeau Algebras

abstract:
  We define natural topologies on the Colombeau algebras which are compatible
with the algebraic structure. These topologies reduces do Scarpalezos sharp
topologies when restricted. with this we take a positive step towards
topological methods of solving P.D. Equations in Colombeau algebras.
Applications will appear elsewhere.


title: The Noncommutative Poisson Algebra of Classical and Quantum Mechanics

abstract:
  The Lie-Rinehart algebra of a manifold M, defined by the Lie structure of the
vector fields, their action and their module structure on the infinitely
differentiable functions on M, is a common, diffeomorphism invariant, algebra
for both classical and quantum mechanics. Its (noncommutative) Poisson
universal enveloping algebra contains a central variable Z which relates the
commutators to the Lie products; classical and quantum mechanics are its only
factorial realizations, corresponding to the indentification of Z with i times
the Planck constant. In this form, canonical quantization appears therefore as
a consequence of such a general geometrical structure. The regular factorial
Hilbert space representations are, for nonzero values of Z, unitarily
equivalent, apart from multiplicity, to one of the irreducible quantum
representations, which are locally Schroedinger and in one to one
correspondence with the unitary irreducible representations of the fundamental
group of M. For Z = 0, if Diff(M) is unitarily implemented, they are unitarily
equivalent, up to multiplicity, to the representation defined by classical
mechanics on M.


title:
Large-angle production of charged pions with 3-12.9 GeV/c incident
  protons on nuclear targets

abstract:
  Measurements of the double-differential charged pion production cross-section
in the range of momentum 100 MeV/c < p < 800 MeV/c and angle 0.35 < \theta <
2.15 rad in proton-beryllium, proton-carbon, proton-aluminium, proton-copper,
proton-tin, proton-tantalum and proton-lead collisions are presented. The data
were taken with the large acceptance HARP detector in the T9 beam line of the
CERN PS. The pions were produced by proton beams in a momentum range from 3
GeV/c to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear
interaction length.


title:
Coamoebas of complex algebraic plane curves and the logarithmic Gauss
  map

abstract:
  The coamoeba of any complex algebraic plane curve $V$ is its image in the
real torus under the argument map. The area counted with multiplicity of the
coamoeba of any algebraic curve in $(\mathbb{C}^*)^2$ is bounded in terms of
the degree of the curve. We show in this Note that up to multiplication by a
constant in $(\mathbb{C}^*)^2$, the complex algebraic plane curves whose
coamoebas are of maximal area (counted with multiplicity) are defined over
$\mathbb{R}$, and their real loci are Harnack curves possibly with ordinary
real isolated double points (c.f. \cite{MR-00}). In addition, we characterize
the complex algebraic plane curves such that their coamoebas contain no
extra-piece.


title: Multiparticle entanglement under the influence of decoherence

abstract:
  We present a method to determine the decay of multiparticle quantum
correlations as quantified by the geometric measure of entanglement under the
influence of decoherence. With this, we compare the robustness of entanglement
in GHZ-, cluster-, W- and Dicke states of four qubits and show that the Dicke
state is most robust. Finally, we determine the geometric measure analytically
for decaying GHZ and cluster states of an arbitrary number of qubits.


title: On the classification of twisting maps between $K^n$ and $K^m$

abstract:
  We define the notion of admissible pair for an algebra $A$, consisting on a
couple $(\Gamma,R)$, where $\Gamma$ is a quiver and $R$ a unital, splitted and
factorizable representation of $\Gamma$, and prove that the set of admissible
pairs for $A$ is in one to one correspondence with the points of the variety of
twisting maps $\mathcal{T}_A^n:=\mathcal{T}(K^n,A)$. We describe all these
representations in the case $A=K^m$.


title: Monad Bundles in Heterotic String Compactifications

abstract:
  In this paper, we study positive monad vector bundles on complete
intersection Calabi-Yau manifolds in the context of E8 x E8 heterotic string
compactifications. We show that the class of such bundles, subject to the
heterotic anomaly condition, is finite and consists of about 7000 models. We
explain how to compute the complete particle spectrum for these models. In
particular, we prove the absence of vector-like family anti-family pairs in all
cases. We also verify a set of highly non-trivial necessary conditions for the
stability of the bundles. A full stability proof will appear in a companion
paper. A scan over all models shows that even a few rudimentary physical
constraints reduces the number of viable models drastically.


title:
Finite time decoherence could be suppressed efficiently in photonic
  crystal

abstract:
  The decoherence of two initially entangled qubits in anisotropic band gap
photonic crystal has been studied analytically without Born or Markovian
approximation. It is shown that the decoherence dynamics of two qubits in
photonic crystal is greatly different from that of two qubits in vacuum or
subjected to usual non-Markovian reservoir. The results also show that the
finite time decoherence invoked by spontaneous emission could be suppressed
efficiently and the entanglement of the Bell state possesses odd parity is more
easily preserved in photonic crystal than that of the Bell state possesses even
parity under the same condition. A store scheme for entangled particle pair is
proposed.


title: Are galaxies extending?

abstract:
  It is suggested that the recently observed size evolution of very massive
compact galaxies in the early universe can be explained, if dark matter is in
Bose Einstein condensate.
  In this model the size of the dark matter halos and galaxies depends on the
correlation length of dark matter and, hence, on the the expansion of the
universe. This theory predicts that the size of the galaxies increases as the
Hubble radius of the universe even without merging, which agrees well with the
recent observational data.


title:
Quantum phase transition in a far from equilibrium steady state of XY
  spin chain

abstract:
  Using quantization in the Fock space of operators we compute the
non-equilibrium steady state in an open Heisenberg XY spin 1/2 chain of finite
but large size coupled to Markovian baths at its ends. Numerical and
theoretical evidence is given for a far from equilibrium quantum phase
transition with spontaneous emergence of long-range order in spin-spin
correlation functions, characterized by a transition from saturation to linear
growth with the size of the entanglement entropy in operator space.


title: Multivariate data analysis: The French way

abstract:
  This paper presents exploratory techniques for multivariate data, many of
them well known to French statisticians and ecologists, but few well understood
in North American culture. We present the general framework of duality diagrams
which encompasses discriminant analysis, correspondence analysis and principal
components, and we show how this framework can be generalized to the regression
of graphs on covariates.


title: GRB 070707: the first short gamma-ray burst observed by INTEGRAL

abstract:
  INTEGRAL has observed 47 long-duration GRBs (T_90 > 2s) and 1 short-duration
GRB (T_90 < 2s) in five years of observation since October 2002. This work
presents the properties of the prompt emission of GRB 070707, which is the
first short hard GRB observed by INTEGRAL. The spectral and temporal properties
of GRB 070707 were determined using the two sensitive coded-mask gamma-ray
instruments on board INTEGRAL, IBIS and SPI. The T_90 duration was 0.8s, and
the spectrum of the prompt emission was obtained by joint deconvolution of IBIS
and SPI data to yield a best fit power-law with photon index alpha = -1.19
+0.14 -0.13, which is consistent with the characteristics of short-hard
gamma-ray bursts. The peak flux over 1 second was 1.79 photons/cm^2/s and the
fluence over the same interval was 2.07 x 10^-7 erg/cm^2 in the energy range
20-200keV. The spectral lag measured between 25-50keV and 100-300keV is 20 +/-
5ms, consistent with the small or negligible lags measured for short bursts.
The spectral and temporal properties of GRB 070707 are comparable to those of
the short hard bursts detected by other gamma-ray satellites, including BATSE
and Swift. We estimate a lower limit on the Lorentz factor Gamma >~ 25 for GRB
070707, assuming the typical redshift for short GRBs of z=0.35. This limit is
consistent with previous estimates for short GRBs and is smaller than the lower
limits of Gamma >~ 100 calculated for long GRBs. If GRB 070707 is a member of
the recently postulated class of short GRBs at z ~ 1, the lower limit on Gamma
increases to Gamma >~ 35.


title: The future of census coverage surveys

abstract:
  A quarter-century of statistical research has shown that census coverage
surveys, valuable as they are in offering a report card on each decennial
census, do not provide usable estimates of geographical differences in
coverage. The determining reason is the large number of ``doubly missing''
people missing both from the census enumeration and from coverage survey
estimates. Future coverage surveys should be designed to meet achievable goals,
foregoing efforts at spatial specificity. One implication is a sample size no
more than about $30,000$, setting free resources for controlling processing
errors and investing in coverage improvement. Possible integration of coverage
measurement with the American Community Survey would have many benefits and
should be given careful consideration.


title: Analysis of Lyapunov Control for Hamiltonian Quantum Systems

abstract:
  We present detailed analysis of the convergence properties and effectiveness
of Lyapunov control design for bilinear Hamiltonian quantum systems based on
the application of LaSalle's invariance principle and stability analysis from
dynamical systems and control theory. For a certain class of Hamiltonians,
strong convergence results can be obtained for both pure and mixed state
systems. The control Hamiltonians for realistic physical systems, however,
generally do not fall in this class. It is shown that the effectiveness of
Lyapunov control design in this case is significantly diminished.


title: Breaking supersymmetry in a one-dimensional random Hamiltonian

abstract:
  The one-dimensional supersymmetric random Hamiltonian
$H_{susy}=-\frac{d^2}{dx^2}+\phi^2+\phi'$, where $\phi(x)$ is a Gaussian white
noise of zero mean and variance $g$, presents particular spectral and
localization properties at low energy: a Dyson singularity in the integrated
density of states (IDoS) $N(E)\sim1/\ln^2E$ and a delocalization transition
related to the behaviour of the Lyapunov exponent (inverse localization length)
vanishing like $\gamma(E)\sim1/|\ln{}E|$ as $E\to0$. We study how this picture
is affected by breaking supersymmetry with a scalar random potential:
$H=H_{susy}+V(x)$ where $V(x)$ is a Gaussian white noise of variance $\sigma$.
In the limit $\sigma\ll{g}^3$, a fraction of states
$N(0)\sim{g}/\ln^2(g^3/\sigma)$ migrate to the negative spectrum and the
Lyapunov exponent reaches a finite value $\gamma(0)\sim{g}/\ln(g^3/\sigma)$ at
E=0. Exponential (Lifshits) tail of the IDoS for $E\to-\infty$ is studied in
detail and is shown to involve a competition between the two noises $\phi$ and
$V$ whatever the larger is. This analysis relies on analytic results for $N(E)$
and $\gamma(E)$ obtained by two different methods: a stochastic method and the
replica method. The problem of extreme value statistics of eigenvalues is also
considered (distribution of the n-th excited state energy). The results are
analyzed in the context of classical diffusion in a random force field in the
presence of random annihilation/creation local rates.


title:
Prospects for detection of very high-energy emission from GRB in the
  context of the external shock model

abstract:
  The detection of the 100 GeV-TeV emission by a gamma-ray burst (GRB) will
provide an unprecedented opportunity to study the nature of the central engine
and the interaction between the relativistic flow and the environment of the
burst's progenitor. In this paper we show that there are exciting prospects of
detecting from the burst by MAGIC high-energy (HE) emission during the early
X-ray flaring activity and, later, during the normal afterglow phase. We also
identify the best observational strategy, trigger conditions and time period of
observation. We determine the expected HE emission from the flaring and
afterglow phases of GRBs in the context of the external shock scenario and
compare them with the MAGIC threshold. We find that an X-ray flare with the
average properties of the class can be detected in the 100 GeV range by MAGIC,
provided that z<0.7. The requested observational window with MAGIC should then
start from 10-20 s after the burst and cover about 1000-2000 s. Furthermore, we
demonstrate that there are solid prospects of detecting the late afterglow
emission in the same energy range for most of the bursts with z<0.5 if the
density of the external medium is n> a few cm^-3. In this case, the MAGIC
observation shall extend to about 10-20 ks. We provide recipes for tailoring
this prediction to the observational properties of each burst,in particular the
fluence in the prompt emission and the redshift, thus allowing an almost real
time decision procedure to decide whether to continue the follow-up observation
of a burst at late times.


title:
Hypergeometric functions over F_p and relations to elliptic curves and
  modular forms

abstract:
  For primes p congruent to 1 mod 12, we present an explicit relation between
the traces of Frobenius on a family of elliptic curves with j-invariant 1728/t
and values of a particular 2F1-hypergeometric function over F_p. Additionally,
we determine a formula for traces of Hecke operators T_k(p) on spaces of cusp
forms of weight k and level 1 in terms of the same traces of Frobenius. This
leads to formulas for Ramanujan's tau-function in terms of hypergeometric
functions.


title: Are there waves in elastic wave turbulence ?

abstract:
  An thin elastic steel plate is excited with a vibrator and its local velocity
displays a turbulent-like Fourier spectrum. This system is believed to develop
elastic wave turbulence. We analyze here the motion of the plate with a
two-point measurement in order to check, in our real system, a few hypotheses
required for the Zakharov theory of weak turbulence to apply. We show that the
motion of the plate is indeed a superposition of bending waves following the
theoretical dispersion relation of the linear wave equation. The nonlinearities
seem to efficiently break the coherence of the waves so that no modal structure
is observed. Several hypotheses of the weak turbulence theory seem to be
verified, but nevertheless the theoretical predictions for the wave spectrum
are not verified experimentally.


title: Granular Rough Sphere in a Low-Density Thermal Bath

abstract:
  We study the stationary state of a rough granular sphere immersed in a
thermal bath composed of point particles. When the center of mass of the sphere
is fixed the stationary angular velocity distribution is shown to be Gaussian
with an effective temperature lower than that of the bath. For a freely moving
rough sphere coupled to the thermostat via inelastic collisions we find a
condition under which the joint distribution of the translational and
rotational velocities is a product of Gaussian distributions with the same
effective temperature. In this rather unexpected case we derive a formula for
the stationary energy flow from the thermostat to the sphere in accordance with
Fourier law.


title: A Brief Comment on the Low-Temperature Structure of LaOFeAs

abstract:
  In a recent paper [arXiv:0804.3569], Takatoshi Nomura {\it et al.} reported a
structural phase transition near 150 K in LaOFeAs and used space group "Cmma"
to describe their X-ray diffraction data. However, they did not discuss how
their proposed structure compares with the early neutron study by Cruz {\it et
al.}[arXiv:0804.0795] where the low temperature structure of LaOFeAs was
described by space group "P112/n". This caused some confusion, suggesting that
there may be some disagreement on the low temperature structure of LaOFeAs as
evidenced by several inquiries that we received. Here we show that the proposed
structures from x-ray and neutron diffraction are basically identical. The P2/c
(i.e., P112/n) cell becomes the primitive cell of the Cmma cell when the
z-coordinate of the oxygen and iron are assumed to be exactly 0 and 0.5 (these
numbers were reported to be -0.0057 and 0.5006 in neutron study). Our
first-principles total-energy calculations suggest that the oxygen and iron
atoms prefer to lie on the z=0 and 1/2 plane, respectively, supporting Cmma
symmetry. However it is more convenient to describe the structural distortion
in the primitive P2/c cell which makes it easier to see the connection between
the high (i.e., P4/nmm) and low temperature structures.


title:
Strange Quark Contribution to the Vector and Axial Form Factors of the
  Nucleon: Combined Analysis of G0, HAPPEx, and Brookhaven E734 Data

abstract:
  The strange quark contribution to the vector and axial form factors of the
nucleon has been determined for momentum transfers in the range $0.45<Q^2<1.0$
GeV$^2$. The results are obtained via a combined analysis of
forward-scattering, parity-violating elastic $\vec{e}p$ asymmetry data from the
G0 and HAPPEx experiments at Jefferson Lab, and elastic $\nu p$ and $\bar{\nu}
p$ scattering data from Experiment 734 at Brookhaven National Laboratory. The
parity-violating asymmetries measured in elastic $\vec{e}p$ scattering at
forward angles establish a relationship between the strange vector form factors
$G_E^s$ and $G_M^s$, with little sensitivity to the strange axial form factor
$G_A^s$. On the other hand, elastic neutrino scattering at low $Q^2$ is
dominated by the axial form factor, with some significant sensitivity to the
vector form factors as well. Combination of the two data sets allows the
simultaneous extraction of $G_E^s$, $G_M^s$, and $G_A^s$ over a significant
range of $Q^2$ for the very first time. The $Q^2$-dependence of the strange
axial form factor suggests that the strange quark contribution to the proton
spin, $\Delta s$, is negative.


title: Control Paradigms for Quantum Engineering

abstract:
  We give an overview of different paradigms for control of quantum systems and
their applications, illustrated with specific examples. We further discuss the
implications of fault-tolerance requirements for quantum process engineering
using optimal control, and explore the possibilities for architecture
simplification and effective control using a minimum number of simple switch
actuators.


title: Learning Low-Density Separators

abstract:
  We define a novel, basic, unsupervised learning problem - learning the lowest
density homogeneous hyperplane separator of an unknown probability
distribution. This task is relevant to several problems in machine learning,
such as semi-supervised learning and clustering stability. We investigate the
question of existence of a universally consistent algorithm for this problem.
We propose two natural learning paradigms and prove that, on input unlabeled
random samples generated by any member of a rich family of distributions, they
are guaranteed to converge to the optimal separator for that distribution. We
complement this result by showing that no learning algorithm for our task can
achieve uniform learning rates (that are independent of the data generating
distribution).


title: Quantization of pseudo-differential operators on the torus

abstract:
  Pseudo-differential and Fourier series operators on the n-torus are analyzed
by using global representations by Fourier series instead of local
representations in coordinate charts. Toroidal symbols are investigated and the
correspondence between toroidal and Euclidean symbols of pseudo-differential
operators is established. Periodization of operators and hyperbolic partial
differential equations is discussed. Fourier series operators, which are
analogues of Fourier integral operators on the torus, are introduced, and
formulae for their compositions with pseudo-differential operators are derived.
It is shown that pseudo-differential and Fourier series operators are bounded
on $L^2$ under certain conditions on their phases and amplitudes.


title: Heterotic supergeometry revisited

abstract:
  The superspace geometry relevant to the heterotic string is reviewed from the
point of view of the off-shell supermultiplet structure of $N=1,d=10$
supergravity. The anomaly-modified seven-form Bianchi identity is analysed at
order $\a'^3$ and shown to admit a complete solution. The corresponding $\a'^3$
deformation of the dimension-zero torsion tensor is derived and shown to obey
the appropriate cohomological constraint.


title: Improving quantum gate fidelities using optimized Euler angles

abstract:
  An explicit algorithm for calculating the optimized Euler angles for both
qubit state transfer and gate engineering given two arbitary fixed Hamiltonians
is presented. It is shown how the algorithm enables us to efficiently implement
single qubit gates even if the control is severely restricted and the
experimentally accessible Hamiltonians are far from orthogonal. It is further
shown that using the optimized Euler angles can significantly improve the
fidelity of quantum operations even for systems where the experimentally
accessible Hamiltonians are nearly orthogonal. Unlike schemes such as composite
pulses, the proposed scheme does not significantly increase the number of local
operations or gate operation times.


title: Can the flyby anomaly be attributed to earth-bound dark matter?

abstract:
  We make preliminary estimates to assess whether the recently reported flyby
anomaly can be attributed to dark matter interactions. We consider both elastic
and exothermic inelastic scattering from dark matter constituents; for
isotropic dark matter velocity distributions, the former decrease, while the
latter increase, the final flyby velocity. The fact that the observed flyby
velocity anomaly shows examples with both positive and negative signs, requires
the dominance of different dark matter scattering processes along different
flyby trajectories. The magnitude of the observed anomalies requires dark
matter densities many orders of magnitude greater than the galactic halo
density. Such a large density could result from an accumulation cascade, in
which the solar system-bound dark matter density is much higher than the
galactic halo density, and the earth-bound density is much higher than the
solar system-bound density. We discuss a number of strong constraints on the
hypothesis of a dark matter explanation for the flyby anomaly. These require
dark matter to be non-self-annihilating, with the dark matter scattering cross
section on nucleons much larger, and the dark matter mass much lighter, than
usually assumed.


title: Crumpled Wires and Liouville Field Theory

abstract:
  The study of the packing of a length of wire in a two dimensional domain is
done using techniques of conformal maps. The resulting scaling properties are
derived through the Coulomb gas formalism of Conformal Field Theories. An
analogy is drawn between this system and the 2D gravitational -- or Liouville
-- coupling of non-conformally invariant matter in two dimensions.


title:
VLA and VLBA Observations of the Highest Redshift Radio-Loud QSO
  J1427+3312 at z = 6.12

abstract:
  We present 8.4 GHz VLA A-array and 1.4 GHz VLBA results on the radio
continuum emission from the highest redshift radio-loud quasar known to date,
the $z=6.12$ QSO J1427+3312. The VLA observations show an unresolved steep
spectrum source with a flux density of $250 \pm 20$ uJy at 8.4GHz and a
spectral index value of $\alpha^{8.4}_{1.4}=-1.1$. The 1.4 GHz VLBA images
reveal several continuum components with a total flux density of $1.778 \pm
0.109$ mJy, which is consistent with the flux density measured with the VLA at
1.4 GHz. Each of these components is resolved with sizes of a few
milliarcseconds, and intrinsic brightness temperatures on the order of $10^7$
to $10^8$ K. The physical characteristics as revealed in these observations
suggest that this QSO may be a Compact Symmetric Object, with the two dominant
components seen with the VLBA, which are separated by 31 mas (174 pc) and have
intrinsic sizes of ~22-34 pc, being the two radio lobes that are confined by
the dense ISM. If indeed a CSO, then the estimated kinematic age of this radio
AGN is only $10^3$ yr.


title: M5-brane in three-form flux and multiple M2-branes

abstract:
  We investigate the Bagger-Lambert-Gustavsson model associated with the
Nambu-Poisson algebra as a theory describing a single M5-brane. We argue that
the model is a gauge theory associated with the volume-preserving
diffeomorphism in the three-dimenisonal internal space. We derive gauge
transformations, actions, supersymmetry transformations, and equations of
motions in terms of six-dimensional fields. The equations of motions are
written in gauge-covariant form, and the equations for tensor fields have
manifest self-dual structure. We demonstrate that the double dimensional
reduction of the model reproduces the non-commutative U(1) gauge theory on a
D4-brane with a small non-commutativity parameter. We establish relations
between parameters in the BLG model and those in M-theory. This shows that the
model describes an M5-brane in a large C-field background.


title:
Moderate deviations for stationary sequences of Hilbert valued bounded
  random variables

abstract:
  In this paper, we derive the moderate deviation principle for stationary
sequences of bounded random variables with values in a Hilbert space. The
conditions obtained are expressed in terms of martingale-type conditions. The
main tools are martingale approximations and a new Hoeffding inequality for non
adpated sequences of Hilbert-valued random variables. Applications to
Cramer-Von Mises statistics, functions of linear processes and stable Markov
chains are given.


title: On almost randomizing channels with a short Kraus decomposition

abstract:
  For large d, we study quantum channels on C^d obtained by selecting randomly
N independent Kraus operators according to a probability measure mu on the
unitary group U(d). When mu is the Haar measure, we show that for
N>d/epsilon^2$, such a channel is epsilon-randomizing with high probability,
which means that it maps every state within distance epsilon/d (in operator
norm) of the maximally mixed state. This slightly improves on a result by
Hayden, Leung, Shor and Winter by optimizing their discretization argument.
Moreover, for general mu, we obtain a epsilon-randomizing channel provided N >
d (\log d)^6/epsilon^2$. For d=2^k (k qubits), this includes Kraus operators
obtained by tensoring k random Pauli matrices. The proof uses recent results on
empirical processes in Banach spaces.


title: Counter example to Strichartz estimates for the wave equation in domains

abstract:
  Let U be a bounded, regular, strictly convex domain of R^2 and consider the
wave equation on U with Dirichlet boundary condition. We prove that in such a
domain the Strichartz estimates for the wave equation suffer losses when
compared to the case U=R^2, at least for a subset of the usual range of
indices.


title: Implementation of Quantum Gates via Optimal Control

abstract:
  Starting with the basic control system model often employed in NMR pulse
design, we derive more realistic control system models taking into account
effects such as off-resonant excitation for systems with fixed inter-qubit
coupling controlled by globally applied electromagnetic fields, as well as for
systems controlled by a combination of a global fields and local control
electrodes. For both models optimal control is used to find controls that
implement a set of two- and three-qubit gates with fidelity greater than
99.99%. While in some cases the optimal pulses obtained appear to be
surprisingly simple and experimentally realistic, the results also show that
the "optimal" pulses obtained in other cases are experimentally infeasible, and
more sophisticated parametrization of the control fields and numerical
algorithms are needed.


title: Central Exclusive Dijet Production

abstract:
  Calculations of central exclusive production are affected by very large
perturbative and non-perturbative corrections. In this talk, we summarize the
results of a study of the uncertainties on these corrections in the case of
exclusive dijet production.


title:
Howe type duality for metaplectic group acting on symplectic spinor
  valued forms

abstract:
  Let $\lambda: \tilde{G}\to G$ be the non-trivial double covering of the
symplectic group $G=Sp(V,\omega)$ of the symplectic vector space $(V,\omega)$
by the metaplectic group $\tilde{G}=Mp(V,\omega).$ In this case, $\lambda$ is
also a representation of $\tilde{G}$ on the vector space $V$ and thus, it gives
rise to the representation of $\tilde{G}$ on the space of exterior forms
$\bigwedge^{\bullet}V^*$ by taking wedge products. Let $S$ be the minimal
globalization of the Harish-Chandra module of the complex Segal-Shale-Weil
representation of the metaplectic group $\tilde{G}.$ We prove that the
associative commutant algebra
$\hbox{End}_{\tilde{G}}(\bigwedge^{\bullet}V^*\otimes S)$ of the metaplectic
group $\tilde{G}$ acting on the $S$-valued exterior forms is generated by
certain representation of the super ortho-symplectic Lie algebra $osp(1|2)$ and
two distinguished operators. This establishes a Howe type duality between the
metaplectic group and the super Lie algebra $\mathfrak{osp}(1|2).$ Also the
space $\bigwedge^{\bullet}V^*\otimes S$ is decomposed wr. to the joint action
of $Mp(V,\omega)$ and $osp(1|2).$


title:
q-Difference equations of KdV type and "Chazy-type" second-degree
  difference equations

abstract:
  By imposing special compatible similarity constraints on a class of
integrable partial $q$-difference equations of KdV-type we derive a hierarchy
of second-degree ordinary $q$-difference equations. The lowest (non-trivial)
member of this hierarchy is a second-order second-degree equation which can be
considered as an analogue of equations in the class studied by Chazy. We
present corresponding isomonodromic deformation problems and discuss the
relation between this class of difference equations and other equations of
Painleve type.


title: Searches for new physics using dijet events at the LHC

abstract:
  We present a concise review of the plans of the ATLAS and CMS collaborations
to search for new physics using dijet events. The inclusive cross section as a
function of jet p$_{T}$, the dijet mass distribution and the dijet ratio's CMS
techniques are presented together with their potential of discovery with a
focus on the integrated luminosities of 10, 100 and 1000 pb$^{-1}$.
Analogously, the inclusive jet and angular distribution searches in the dijet
channel from ATLAS are presented together with the potential of discovery given
in terms of needed integrated luminosity.


title: Vector partition function and generalized Dahmen-Micchelli spaces

abstract:
  This is the first of two papers on partition functions and the index theory
of transversally elliptic operators. In this paper we only discuss algebraic
and combinatorial issues related to partition functions. The applications to
index theory will appear in a subsequent paper.


title:
Evolution of the neutron quasi-elastic scattering through the
  ferroelectric phase transition in 93%PbZn$_{1/3}$Nb$_{2/3}$O$_3$ - 7%
  PbTiO$_3$

abstract:
  We show that the neutron diffuse scattering in relaxor ferroelectric
(1-x)PbZn$_{1/3}$Nb$_{2/3}$O$_{3}$ - x PbTiO$_{3}$ (x=0.07) consists of two
components. The first component is strictly elastic but extended in q-space and
grows below 600 K. The second component, that was not reported before for the
(1-x)PbZn$_{1/3}$Nb$_{2/3}$O$_{3}$ - x PbTiO$_{3}$ (x=0.07) relaxor
ferroelectrics, is quasi-elastic with a line-width that has a similar
temperature dependence as the width of the central peak observed by Brillouin
spectroscopy. The temperature dependence of the susceptibility of the
quasi-elastic scattering has a maximum at the ferroelectric transition.


title:
Investigating the Ultraviolet Properties of Gravity with a Wilsonian
  Renormalization Group Equation

abstract:
  We review and extend in several directions recent results on the asymptotic
safety approach to quantum gravity. The central issue in this approach is the
search of a Fixed Point having suitable properties, and the tool that is used
is a type of Wilsonian renormalization group equation. We begin by discussing
various cutoff schemes, i.e. ways of implementing the Wilsonian cutoff
procedure. We compare the beta functions of the gravitational couplings
obtained with different schemes, studying first the contribution of matter
fields and then the so-called Einstein-Hilbert truncation, where only the
cosmological constant and Newton's constant are retained. In this context we
make connection with old results, in particular we reproduce the results of the
epsilon expansion and the perturbative one loop divergences. We then apply the
Renormalization Group to higher derivative gravity. In the case of a general
action quadratic in curvature we recover, within certain approximations, the
known asymptotic freedom of the four-derivative terms, while Newton's constant
and the cosmological constant have a nontrivial fixed point. In the case of
actions that are polynomials in the scalar curvature of degree up to eight we
find that the theory has a fixed point with three UV-attractive directions, so
that the requirement of having a continuum limit constrains the couplings to
lie in a three-dimensional subspace, whose equation is explicitly given. We
emphasize throughout the difference between scheme-dependent and
scheme-independent results, and provide several examples of the fact that only
dimensionless couplings can have "universal" behavior.


title:
Collective States and Symmetric Local Decoherence in Large Ensembles of
  Qubits

abstract:
  The symmetric collective states of an atomic spin ensemble (i.e., many-body
states that are invariant under particle exchange) are not preserved by
decoherence that acts identically but individually on members of the ensemble.
We develop a class of collective states in an ensemble of N spin-1/2 particles
that is invariant under symmetric local decoherence and find that the dimension
of the Hilbert space spanned by these collective states scales only as N^2. We
then investigate the open system dynamics of experimentally relevant
non-classical collective atomic states, including Schroedinger cat and spin
squeezed states, subject to various symmetric but local decoherence models.


title: Collective processes of an ensemble of spin-1/2 particles

abstract:
  When the dynamics of a spin ensemble are expressible solely in terms of
symmetric processes and collective spin operators, the symmetric collective
states of the ensemble are preserved. These many-body states, which are
invariant under particle relabeling, can be efficiently simulated since they
span a subspace whose dimension is linear in the number of spins. However, many
open system dynamics break this symmetry, most notably when ensemble members
undergo identical, but local, decoherence. In this paper, we extend the
definition of symmetric collective states of an ensemble of spin-1/2 particles
in order to efficiently describe these more general collective processes. The
corresponding collective states span a subspace which grows quadratically with
the number of spins. We also derive explicit formulae for expressing arbitrary
identical, local decoherence in terms of these states.


title:
Organizational and dynamical aspects of a small network with two
  distinct communities : Neo creationists vs. Evolution Defenders

abstract:
  Social impacts and degrees of organization inherent to opinion formation for
interacting agents on networks present interesting questions of general
interest from physics to sociology. We present a quantitative analysis of a
case implying an evolving small size network, i.e. that inherent to the ongoing
debate between modern creationists (most are Intelligent Design (ID) proponents
(IDP)) and Darwin's theory of Evolution Defenders (DED)). This study is carried
out by analyzing the structural properties of the citation network unfolded in
the recent decades by publishing works belonging to members of the two
communities. With the aim of capturing the dynamical aspects of the interaction
between the IDP and DED groups, we focus on $two$ key quantities, namely, the
{\it degree of activity} of each group and the corresponding {\it degree of
impact} on the intellectual community at large. A representative measure of the
former is provided by the {\it rate of production of publications} (RPP),
whilst the latter can be assimilated to the{\it rate of increase in citations}
(RIC). These quantities are determined, respectively, by the slope of the time
series obtained for the number of publications accumulated per year and by the
slope of a similar time series obtained for the corresponding citations. The
results indicate that in this case, the dynamics can be seen as geared by
triggered or damped competition. The network is a specific example of marked
heterogeneity in exchange of information activity in and between the
communities, particularly demonstrated through the nodes having a high
connectivity degree, i.e. opinion leaders.


title: The running of the coupling in SU(N) pure gauge theories

abstract:
  The running of the coupling is studied in SU(4) gauge theory using the
Schr\"odinger functional technique. Up to energies of the order of the square
root of the string tension $\sigma$, the running is found to agree with the
two-loop perturbative formula. Relating the perturbative to the
non-perturbative regime of the running and converting to the $\msbar$ scheme
allows one to extract the ratio $\Lambda_{\msbar}/\sqrt{\sigma}$. The result is
then used in combination with similar calculations present in the literature
for SU(2) and SU(3) to extract $\Lambda_{\msbar}/\sqrt{\sigma}$ in the large
$N$ limit. Our results for $N=3,4$ agree with a recent study of the same
quantity performed using the Parisi mean field scheme as an intermediate
scheme, while $\Lambda_{\msbar}/\sqrt{\sigma}$ in SU(2) turns out to differ by
2.5%. Possible explanations of this discrepancy are discussed.


title:
FLAMES spectroscopy of low-mass stars in the young clusters sigma Ori
  and lambda Ori

abstract:
  Aims. We performed a detailed membership selection and studied the accretion
properties of low-mass stars in the two apparently very similar young (1-10
Myr) clusters sigma Ori and lambda Ori.
  Methods. We observed 98 and 49 low-mass (0.2-1.0 M_sun) stars in sigma Ori
and lambda Ori respectively, using the multi-object optical spectrograph FLAMES
at the VLT, with the high-resolution (R=17,000) HR15N grating (6470-6790 AA).
We used radial velocities, Li and Halpha to establish cluster membership and
Halpha and other optical emission lines to analyze the accretion properties of
members.
  Results. We identified 65 and 45 members of the sigma Ori and lambda Ori
clusters, respectively and discovered 16 new candidate binary systems. We also
measured rotational broadening for 20 stars and estimated the mass accretion
rates in 25 stars of the sigma Ori cluster, finding values between 10^-11 and
10^-7.7 M_sun yr^-1 and in 4 stars of the lambda Ori cluster, finding values
between 10^-11 and 10^-10.1 M_sun yr-1. Comparing our results with the infrared
photometry obtained by the Spitzer satellite, we find that the fraction of
stars with disks and the fraction of active disks is larger in the sigma Ori
cluster (52+-9% and 78+-16%) than in lambda Ori (28+-8% and 40+-20%)
  Conclusions. The different disk and accretion properties of the two clusters
could be due either to the effect of the high-mass stars and the supernova
explosion in the lambda Ori cluster or to different ages of the cluster
populations. Further observations are required to draw a definitive conclusion.


title: The line bundles on moduli stacks of principal bundles on a curve

abstract:
  Let G be an affine reductive algebraic group over an algebraically closed
field k. We determine the Picard group of the moduli stacks of principal
G-bundles on any smooth projective curve over k.


title: Spectroscopy, leptonic decays and the nature of heavy quarkonia

abstract:
  We examine the electronic width ratios of Upsilon resonances below the BBbar
threshold by means of an effective (Cornell-type) QCD potential incorporating
1/m_b corrections obtained from a prior fit to the bottomonium spectrum. From
our analysis we conclude that the Upsilon(2S) and Upsilon(3S) states should
belong to the strong-coupling (nonperturbative) regime while the Upsilon(1S)
state should belong to the weak-coupling (perturbative) regime, in agreement
with a previous study based on radiative decays.


title: Optimal reconstruction systems for erasures and for the q-potential

abstract:
  We introduce the $q$-potential as an extension of the Benedetto-Fickus frame
potential, defined on general reconstruction systems and we show that protocols
are the minimizers of this potential under certain restrictions. We extend
recent results of B.G. Bodmann on the structure of optimal protocols with
respect to 1 and 2 lost packets where the worst (normalized) reconstruction
error is computed with respect to a compatible unitarily invariant norm. We
finally describe necessary and sufficient (spectral) conditions, that we call
$q$-fundamental inequalities, for the existence of protocols with prescribed
properties by relating this problem to Klyachko's and Fulton's theory on sums
of hermitian operators.


title: Origin of Spin Hall Effect (Reply to Comment)

abstract:
  Conceptual framework behind the intrinsic spin Hall effect in
three-dimensional conductors is discussed. Theory suggests how the spin Hall
current should depend on symmetry and orientation of the crystal.


title:
Vibrational coherence in electron spin resonance in nanoscale
  oscillators

abstract:
  We study a scheme for electrical detection, using electron spin resonance, of
coherent vibrations in a molecular single electron level trapped near a
conduction channel. Both equilibrium spin-currents and non-equilibrium spin-
and charge currents are investigated. Inelastic side-band anti-resonances
corresponding to the vibrational modes appear in the electron spin resonance
spectrum.


title:
Survival probability of a particle in a sea of mobile traps: A tale of
  tails

abstract:
  We study the long-time tails of the survival probability $P(t)$ of an $A$
particle diffusing in $d$-dimensional media in the presence of a concentration
$\rho$ of traps $B$ that move sub-diffusively, such that the mean square
displacement of each trap grows as $t^{\gamma}$ with $0\leq \gamma \leq 1$.
Starting from a continuous time random walk (CTRW) description of the motion of
the particle and of the traps, we derive lower and upper bounds for $P(t)$ and
show that for $\gamma \leq 2/(d+2)$ these bounds coincide asymptotically, thus
determining asymptotically exact results. The asymptotic decay law in this
regime is exactly that obtained for immobile traps. This means that for
sufficiently subdiffusive traps, the moving $A$ particle sees the traps as
essentially immobile, and Lifshitz or trapping tails remain unchanged. For
$\gamma > 2/(d+2)$ and $d\leq 2$ the upper and lower bounds again coincide,
leading to a decay law equal to that of a stationary particle. Thus, in this
regime the moving traps see the particle as essentially immobile. For $d>2$,
however, the upper and lower bounds in this $\gamma$ regime no longer coincide
and the decay law for the survival probability of the $A$ particle remains
ambiguous.


title: XO-4b: An Extrasolar Planet Transiting an F5V Star

abstract:
  We report the discovery of the planet XO-4b, which transits the star XO-4
(GSC 03793-01994, V=10.7, F5V). Transits are 1.0% deep and 4.4 hours in
duration. The star XO-4 has a mass of 1.32 M_sun.... The planet XO-4b has a
mass of 1.72 M_Jup....radius of 1.34 R_Jup...orbital period 4.125 days. We
analyze scintillation-limited differential R-band photometry of XO-4b in
transit made with a 1.8-m telescope under photometric conditions, yielding
photometric precision of 0.6 to 2.0 millimag per one-minute interval. The
declination of XO-4 places it within the continuous viewing zone of the Hubble
Space Telescope (HST), which permits observation without interruption caused by
occultation by the Earth. Because the stellar rotation periods of the three
hottest stars orbited by transiting gas-giant planets are 2.0, 1.1, and 2.0
times the planetary orbital periods, we note the possibility of resonant
interaction.


title: Functional approach to the fermionic Casimir effect

abstract:
  We use a functional approach to calculate the Casimir energy due to Dirac
fields in interaction with thin, flat, parallel walls, which implement
imperfect bag-like boundary conditions. These are simulated by the introduction
of delta-like interactions with the walls. We show that, with a proper choice
for the corresponding coupling constants, bag-model boundary condition are
properly implemented. We obtain explicit expressions for the energies in 1+1
and 3+1 dimensions, for massless and massive fields.


title: K$^+$-nucleon interaction

abstract:
  The Born approximation to the quark-gluon-exchange mechanism for K$^+$N
scattering is used as a starting point to generate a potential for this system.
The valence quark wave function of the nucleon is generalized from a single
Gaussian to a sum of Gaussians in order to have a more flexible representation
than previous work. We obtain a potential derived from a valence density given
by lattice calculations. By comparing with a recent amplitude analysis it is
found that the strength of the quark-gluon based potential needs to be
increased by a factor of order 2-4 relative to the normalization given by more
traditional values of the governing parameters. The method is used to estimate
the change in effective K$^+$N amplitudes which would result from changes in
the valence quark distributions or strength of the interaction which might
arise from nuclear medium effects in K$^+$ scattering from nuclei.


title:
Atmospheric, long baseline, and reactor neutrino data constraints on
  $\theta_{13}$

abstract:
  A new atmospheric neutrino oscillation tool which utilizes full three
neutrino oscillation probabilities and a full three neutrino treatment of the
MSW effect is combined with a standard analysis of the K2K, MINOS, and CHOOZ
data to examine the bounds on $\theta_{13}$ implied by existing data, including
the recent, more finely binned, Super-K atmospheric data. In the region
$L/E_\nu\gtrsim 10^4$ km/GeV, we have previously found that the sub-dominant
expansion does not converge and that terms linear in $\theta_{13}$ can be
significant. The current analysis confirms this and leads to the conclusion
that $\theta_{13}$ is bounded from above by the atmospheric data while CHOOZ
provides the lower bound. We trace the origin of this result to fully contained
data in the previously mentioned very long baseline region, to a combination of
a quadratic in $\theta_{13}$ term in ${\mathcal P}_{ee}$ and a linear term in
${\mathcal P}_{e\mu}$ and their contribution to $R_e$, a broad MSW resonance
for the solar mass-squared difference at 180 MeV, and an increase in
$\theta_{12}$ due to this resonant matter effect which alters the sign of the
linear in $\theta_{13}$ term. Assuming CP is conserved in the lepton sector, we
find $\theta_{13}=-0.07^{+0.18}_{-0.11}$, the asymmetry being a reflection of
the importance of the linear in $\theta_{13}$ terms.


title:
Asymptotically linear solutions in H^1 of the 2-d defocusing nonlinear
  Schroedinger and Hartree equations

abstract:
  In the 2-d setting, given an $H^1$ solution $v(t)$ to the linear
Schr\"odinger equation $i\partial_t v +\Delta v =0$, we prove the existence
(but not uniqueness) of an $H^1$ solution $u(t)$ to the defocusing nonlinear
Schr\"odinger (NLS) equation $i\partial_t u + \Delta u -|u|^{p-1}u=0$ for
nonlinear powers $2<p<3$ and the existence of an $H^1$ solution $u(t)$ to the
defocusing Hartree equation $i\partial_t u + \Delta u
-(|x|^{-\gamma}\star|u|^{2})u=0$ for interaction powers $1<\gamma<2$, such that
$\|u(t)-v(t)\|_{H^1} \to 0$ as $t\to +\infty$. This is a partial result toward
the existence of well-defined continuous wave operators $H^1 \to H^1$ for these
equations. For NLS in 2-d, such wave operators are known to exist for $p\geq
3$, while for $p\leq 2$ it is known that they cannot exist. The Hartree
equation in 2-d only makes sense for $0<\gamma<2$, and it was previously known
that wave operators cannot exist for $0<\gamma\leq 1$, while no result was
previously known in the range $1<\gamma<2$. Our proof in the case of NLS
applies a new estimate of Colliander-Grillakis-Tzirakis (2008) to a strategy
devised by Nakanishi (2001). For the Hartree equation, we prove a new
correlation estimate following the method of Colliander-Grillakis-Tzirakis
(2008).


title: Nonlocal Special Relativity

abstract:
  In the special theory of relativity, Lorentz invariance is extended in
Minkowski spacetime from ideal inertial observers to actual observers by means
of the hypothesis of locality, which postulates that accelerated observers are
always pointwise inertial. A critical examination of the locality assumption
reveals its domain of validity: it is true for pointwise coincidences, but is
in conflict with wave-particle duality. To remedy this situation, a nonlocal
theory of accelerated systems is presented that reduces to the standard theory
in the limit of small accelerations. Some of the main consequences of nonlocal
special relativity are briefly outlined.


title: Modeling Heavy Ion Collisions in AdS/CFT

abstract:
  We construct a model of high energy heavy ion collisions as two
ultrarelativistic shock waves colliding in AdS_5. We point out that shock waves
corresponding to physical energy-momentum tensors of the nuclei completely stop
almost immediately after the collision in AdS_5, which, on the field theory
side, corresponds to complete nuclear stopping due to strong coupling effects,
likely leading to Landau hydrodynamics. Since in real-life heavy ion collisions
the large Bjorken x part of nuclear wave functions continues to move along the
light cone trajectories of the incoming nuclei leaving the small-x partons
behind, we conclude that a pure large coupling approach is not likely to
adequately model nuclear collisions. We show that to account for small-coupling
effects one can model the colliding nuclei by two (unphysical)
ultrarelativistic shock waves with zero net energy each (but with non-zero
energy density). We use this model to study the energy density of the
strongly-coupled matter created immediately after the collision. We argue that
expansion of the energy density in the powers of proper time squared
corresponds on the gravity side to a perturbative expansion of the metric in
graviton exchanges. Using such expansion we reproduce our earlier result that
the energy density of produced matter at mid-rapidity starts out as a constant
(of time) in heavy ion collisions at large coupling.


title: The pre-ZAMS nature of Mol160/IRAS23385+6053 confirmed by Spitzer

abstract:
  Determining the timeline for the formation of massive YSOs requires the
identification and characterisation of all the phases that a massive forming
YSO undergoes. It is of particular interest to verify the observability of the
phase in which the object is rapidly accreting while not yet igniting the
fusion of hydrogen that marks the arrival on the ZAMS. One of the candidate
prototypical objects for this phase is Mol160/IRAS23385+6053, which previous
studies suggest it could be in a pre-Hot Core stage. We further investigate
this issue by means of Spitzer imaging and spectroscopy in the 5-70 micron
range. The dense core of Mol160/IRAS23385+6053, which up to now had only been
detected at submm and mm wavelenghts has been revealed for the first time at 24
and 70 micron by Spitzer. The complete 24 micron -3.4 mm continuum cannot be
fitted with a standard model of a Zero-Age Main-Sequence (ZAMS) star embedded
in an envelope. A simple greybody fit yields a mass of 220 solar masses. The
luminosity is slightly in excess of 3000 solar luminosities, which is a factor
of 5 less than previous estimates when only IRAS fluxes were available between
20 and 100 micron. The source is under-luminous by the same factor with respect
to UCHII regions or Hot-Cores of similar circumstellar mass, and simple models
show that this is compatible with an earlier evolutionary stage. Spectroscopy
between 5 and 40 microns revelas typical PDR/PIR conditions, where the required
UV illumination may be provided by other sources revealed at 24 microns in the
same region, and which can be plausibly modeled as moderately embedded
intermediate-mass ZAMS stars. Our results strengthen the suggestion that the
central core in Mol160/IRAS23385+6053 is a massive YSO actively accreting from
its circumstellar envelope and which did not yet begin hydrogen fusion.


title: A stable absorbing boundary layer for anisotropic waves

abstract:
  For some anisotropic wave models, the PML (perfectly matched layer) method of
open boundaries can become polynomially or exponentially unstable in time. In
this work we present a new method of open boundaries, the phase space filter,
which is stable for all wave equations.
  Outgoing waves can be characterized as waves located near the boundary of the
computational domain with group velocities pointing outward. The phase space
filtering algorithm consists of applying a filter to the solution that removes
outgoing waves only.
  The method presented here is a simplified version of the original phase space
filter, originally described in [22] for the Schrodinger equation. We apply
this method to anisotropic wave models for which the PML is unstable, namely
the Euler equations (linearized about a constant jet flow) and Maxwell's
equations in an anisotropic medium. Stability of the phase space filter is
proved.


title:
A Compendium of Far-Infrared Line and Continuum Emission for 227
  Galaxies Observed by the Infrared Space Observatory

abstract:
  Far-infrared line and continuum fluxes are presented for a sample of 227
galaxies observed with the Long Wavelength Spectrometer on the Infrared Space
Observatory. The galaxy sample includes normal star-forming systems,
starbursts, and active galactic nuclei covering a wide range of colors and
morphologies. The dataset spans some 1300 line fluxes, 600 line upper limits,
and 800 continuum fluxes. Several fine structure emission lines are detected
that arise in either photodissociation or HII regions: [OIII]52um, [NIII]57um,
[OI]63um, [OIII]88um, [NII]122um, [OI]145um, and [CII]158um. Molecular lines
such as OH at 53um, 79um, 84um, 119um, and 163um, and H2O at 58um, 66um, 75um,
101um, and 108um are also detected in some galaxies. In addition to those lines
emitted by the target galaxies, serendipitous detections of Milky Way
[CII]158um and an unidentified line near 74um in NGC1068 are also reported.
Finally, continuum fluxes at 52um, 57um, 63um, 88um, 122um, 145um, 158um, and
170um are derived for a subset of galaxies in which the far-infrared emission
is contained within the ~75" ISO LWS beam. The statistics of this large
database of continuum and line fluxes, including trends in line ratios with the
far-infrared color and infrared-to-optical ratio, are explored.


title: The Space of Symplectic Structures on Closed 4-Manifolds

abstract:
  This is a survey paper on the space of symplectic structures on closed
4-manifolds, for the Proceedings ICCM 2004


title: Wintenberger's Functor for Abelian Extensions

abstract:
  Let $k$ be a finite field. Wintenberger used the field of norms to give an
equivalence between a category whose objects are totally ramified abelian
$p$-adic Lie extensions $E/F$, where $F$ is a local field with residue field
$k$, and a category whose objects are pairs $(K,A)$, where $K\cong k((T))$ and
$A$ is an abelian $p$-adic Lie subgroup of $\Aut_k(K)$. In this paper we extend
this equivalence to allow $\Gal(E/F)$ and $A$ to be arbitrary abelian pro-$p$
groups.


title: Holographic QCD with Topologically Charged Domain-Wall/Membranes

abstract:
  We study the thermodynamical phase structures of holographic QCD with
nontrivial topologically charged domain-wall/membranes which are originally
related to the multiple $\theta$-vacua in the large $N_c$ limit. We realize the
topologically charged membranes as the holographic D6-brane fluxes in the
Sakai-Sugimoto model. The D6-brane fluxes couple to the probe D8-anti-D8 via
Chern-Simon term, and act as the source for the baryonic current density of
QCD. We find rich phase structures of the dual meson system by varying
asymptotic separation of D8 and anti-D8. Especially, there can be a
thermodynamically favored and stable phase of finite baryonic current density.
This provides the supporting evidence for the discovery of the topologically
charged membranes found in the lattice QCD calculations. We also find a
crossover phase with the limiting baryonic current density and temperature
which suggest a Hagedorn-like phase transition of meson dissociation.


title: Modified Schmidt games and Diophantine approximation with weights

abstract:
  We show that the sets of weighted badly approximable vectors in $\Bbb R^n$
are winning sets of certain games, which are modifications of
$(\alpha,\beta)$-games introduced by W. Schmidt in 1966. The latter winning
property is stable with respect to countable intersections, and is shown to
imply full Hausdorff dimension.


title: Quantum Gravity Yesterday and Today

abstract:
  We present a talk given by Bryce DeWitt on Quantum Gravity, and present many
references.
  This article is the first installment of the book "The Pursuit of Quantum
Gravity 1946-2004; Memoirs of Bryce DeWitt" that Cecile DeWitt is preparing.


title: Markovian log-supermodularity, and its applications in phylogenetics

abstract:
  We establish a log-supermodularity property for probability distributions on
binary patterns observed at the tips of a tree that are generated under any
2--state Markov process. We illustrate the applicability of this result in
phylogenetics by deriving an inequality relevant to estimating expected future
phylogenetic diversity under a model of species extinction. In a further
application of the log-supermodularity property, we derive a purely
combinatorial inequality for the parsimony score of a binary character. The
proofs of our results exploit two classical theorems in the combinatorics of
finite sets.


title: Achieving very long lifetimes in optical lattices with pulsed cooling

abstract:
  We have realized a one dimensional optical lattice for individual atoms with
a lifetime >300 s, which is 5 times longer than previously reported. In order
to achieve this long lifetime, it is necessary to laser cool the at-oms briefly
every 20 s to overcome heating due to technical fluctuations in the trapping
potential. Without cooling, we observe negligible atom loss within the first 20
s followed by an exponential decay with a 62 s time constant. We obtain
quantitative agreement with the measured fluctuations of the trapping potential
and the corresponding theoretical heating rates.


title: Steganography of VoIP Streams

abstract:
  The paper concerns available steganographic techniques that can be used for
creating covert channels for VoIP (Voice over Internet Protocol) streams. Apart
from characterizing existing steganographic methods we provide new insights by
presenting two new techniques. The first one is network steganography solution
which exploits free/unused protocols' fields and is known for IP, UDP or TCP
protocols but has never been applied to RTP (Real-Time Transport Protocol) and
RTCP (Real-Time Control Protocol) which are characteristic for VoIP. The second
method, called LACK (Lost Audio Packets Steganography), provides hybrid
storage-timing covert channel by utilizing delayed audio packets. The results
of the experiment, that was performed to estimate a total amount of data that
can be covertly transferred during typical VoIP conversation phase, regardless
of steganalysis, are also included in this paper.


title:
Limits on spin-dependent WIMP-nucleon cross-sections from the XENON10
  experiment

abstract:
  XENON10 is an experiment to directly detect weakly interacting massive
particle (WIMPs), which may comprise the bulk of the non-baryonic dark matter
in our Universe. We report new results for spin-dependent WIMP-nucleon
interactions with 129-Xe and 131-Xe from 58.6 live-days of operation at the
Laboratori Nazionali del Gran Sasso (LNGS). Based on the non-observation of a
WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously
unexplored regions in the theoretically allowed parameter space for
neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range
of 10 GeV -2 TeV as a dark matter candidate under standard assumptions for its
density and distribution in the galactic halo.


title:
A search for damped Lyman-alpha systems towards radio-loud quasars I:
  The optical survey

abstract:
  We present the results from the optical component of a survey for damped
Lyman-alpha systems (DLAs) towards radio-loud quasars. Our quasar sample is
drawn from the Texas radio survey with the following primary selection
criteria: z_em > 2.4, optical magnitudes B < 22 and 365 MHz flux density S_365
> 400 mJy. We obtained spectra for a sample of 45 QSOs with the William
Herschel Telescope, Very Large Telescope and Gemini-North, resulting in a
survey redshift path Delta z = 38.79. We detect nine DLAs and one sub-DLA with
a mean absorption redshift <z> = 2.44. The DLA number density is n(z) =
0.23^{+0.11}_{-0.07}, in good agreement with the value derived for DLAs
detected in the Sloan Digital Sky Survey at this redshift. The DLA number
density of our sample is also in good agreement with optically-complete
radio-selected samples, supporting previous claims that n(z) is not
significantly affected by dust obscuration bias. We present N(HI) column
density determinations and metal line equivalent width measurements for all our
DLAs. The low frequency flux density selection criterion used for the quasar
sample implies that all absorbers will be suitable for follow-up absorption
spectroscopy in the redshifted HI 21 cm line. A following paper (Kanekar et
al.) will present HI 21 cm absorption studies of, and spin temperature
determinations for, our DLA sample.


title: Transient Astrophysical Pulses and Quantum Gravity

abstract:
  Searches for transient astrophysical pulses could open an exciting new window
into the fundamental physics of quantum gravity. In particular, an evaporating
primordial black hole in the presence of an extra dimension can produce a
detectable transient pulse. Observations of such a phenomenon can in principle
explore the electroweak energy scale, indicating that astrophysical probes of
quantum gravity can successfully complement the exciting new physics expected
to be discovered in the near future at the Large Hadron Collider.


title:
Genuine multipartite entanglement of symmmetric Gaussian states: Strong
  monogamy, unitary localization, scaling behavior, and molecular sharing
  structure

abstract:
  We investigate the structural aspects of genuine multipartite entanglement in
Gaussian states of continuous variable systems. Generalizing the results of
[Adesso & Illuminati, Phys. Rev. Lett. 99, 150501 (2007)], we analyze whether
the entanglement shared by blocks of modes distributes according to a strong
monogamy law. This property, once established, allows to quantify genuine
N-partite entanglement in terms of the "residual contangle" not encoded into
2,...,K,...,(N-1)-partite quantum correlations. The explicit expression of this
entanglement measure is derived, by a recursive formula, for a subclass of
Gaussian states. These are fully symmetric (permutation-invariant) states
multi-partitioned into blocks, each consisting of an arbitrary number of modes.
We compute the genuine multipartite entanglement shared by the blocks
("molecules") and investigate its scaling properties with the number and size
of the molecules, the total number of modes, the global mixedness of the state,
and the squeezed resources. To achieve the exact computation we prove a general
result of symplectic analysis: Correlations among K molecules in N-mode
multi-symmetric Gaussian states can be transformed by a local unitary operation
into correlations shared by K single modes, one per molecule, in effective
non-symmetric states. Due to this theorem, the above results extend to the
subclass of non-symmetric Gaussian states that are obtained by unitarily
localizing the multipartite molecular entanglement of symmetric states. These
findings provide evidence that distributed Gaussian entanglement is strongly
monogamous even beyond specific symmetry constraints, and that the residual
contangle is a bona fide measure of genuine multipartite entanglement for
permutation-invariant Gaussian states under any multi-partition of the modes.


title:
Modulus-dominated SUSY-breaking soft terms in F-theory and their test at
  LHC

abstract:
  We study the general patterns of SUSY-breaking soft terms arising under the
assumption of Kahler moduli dominated SUSY-breaking in string theory models.
Insisting that all MSSM gauginos get masses at leading order and that the top
Yukawa coupling is of order the gauge coupling constant identifies the class of
viable models. These are models in which the SM fields live either in the bulk
or at the intersection of local sets of Type IIB D7-branes or their F-theory
relatives. General arguments allow us to compute the dependence of the Kahler
metrics of MSSM fields on the local Kahler modulus of the brane configuration
in the large moduli approximation. We illustrate this study in the case of
toroidal/orbifold orientifolds but discuss how the findings generalize to the
F-theory case which is more naturally compatible with coupling unification.
Only three types of 7-brane configurations are possible, leading each of them
to very constrained patterns of soft terms for the MSSM. We study their
consistency with radiative electroweak symmetry breaking and other
phenomenological constraints. We find that essentially only the configuration
corresponding to intersecting 7-branes is compatible with all present
experimental constraints and the desired abundance of neutralino dark matter.
The obtained MSSM spectrum is very characteristic and could be tested at LHC.
We also study the LHC reach for the discovery of this type of SUSY particle
spectra.


title: Implementing General Gauge Mediation

abstract:
  Recently there has been much progress in building models of gauge mediation,
often with predictions different than those of minimal gauge mediation. Meade,
Seiberg, and Shih have characterized the most general spectrum which can arise
in gauge mediated models. We discuss some of the challenges of building models
of General Gauge Mediation, especially the problem of messenger parity and
issues connected with R symmetry breaking and CP violation. We build a variety
of viable, weakly coupled models which exhibit some or all of the possible low
energy parameters.


title:
A comprehensive Maximum Likelihood analysis of the structural properties
  of faint Milky Way satellites

abstract:
  We derive the structural parameters of the recently discovered very low
luminosity Milky Way satellites through a Maximum Likelihood algorithm applied
to SDSS data. For each satellite, even when only a few tens of stars are
available down to the SDSS flux limit, the algorithm yields robust estimates
and errors for the centroid, position angle, ellipticity, exponential
half-light radius and number of member stars. This latter parameter is then
used in conjunction with stellar population models of the satellites to derive
their absolute magnitudes and stellar masses, accounting for `CMD shot-noise'.
We find that faint systems are somewhat more elliptical than initially found
and ascribe that to the previous use of smoothed maps which can be dominated by
the smoothing kernel. As a result, the faintest half of the Milky Way dwarf
galaxies (M_V>-7.5) is significantly (4-sigma) flatter (e=0.47+/-0.03) than its
brightest half (M_V<-7.5, e=0.32+/-0.02). From our best models, we also
investigate whether the seemingly distorted shape of the satellites, often
taken to be a sign of tidal distortion, can be quantified. We find that, except
for tentative evidence of distortion in CVnI and UMaII, these can be completely
accounted for by Poisson scatter in the sparsely sampled systems. We consider
three scenarios that could explain the rather elongated shape of faint
satellites: rotation supported systems, stars following the shape of more
triaxial dark matter subhalos, or elongation due to tidal interaction with the
Milky Way. Although none of these is entirely satisfactory, the last one
appears the least problematic, but warrants much deeper observations to track
evidence of such tidal interaction.


title: A Flexible Method of Estimating Luminosity Functions

abstract:
  We describe a Bayesian approach to estimating luminosity functions. We derive
the likelihood function and posterior probability distribution for the
luminosity function, given the observed data, and we compare the Bayesian
approach with maximum-likelihood by simulating sources from a Schechter
function. For our simulations confidence intervals derived from bootstrapping
the maximum-likelihood estimate can be too narrow, while confidence intervals
derived from the Bayesian approach are valid. We develop our statistical
approach for a flexible model where the luminosity function is modeled as a
mixture of Gaussian functions. Statistical inference is performed using Markov
chain Monte Carlo (MCMC) methods, and we describe a Metropolis-Hastings
algorithm to perform the MCMC. The MCMC simulates random draws from the
probability distribution of the luminosity function parameters, given the data,
and we use a simulated data set to show how these random draws may be used to
estimate the probability distribution for the luminosity function. In addition,
we show how the MCMC output may be used to estimate the probability
distribution of any quantities derived from the luminosity function, such as
the peak in the space density of quasars. The Bayesian method we develop has
the advantage that it is able to place accurate constraints on the luminosity
function even beyond the survey detection limits, and that it provides a
natural way of estimating the probability distribution of any quantities
derived from the luminosity function, including those that rely on information
beyond the survey detection limits.


title:
The Atomic to Molecular Transition in Galaxies. I: An Analytic
  Approximation for Photodissociation Fronts in Finite Clouds

abstract:
  In this series of papers we study the structure of the atomic to molecular
transition in the giant atomic-molecular complexes that are the repositories of
most molecular gas in galaxies, with the ultimate goal of attaining a better
understanding of what determines galaxies' molecular content. Here we derive an
approximate analytic solution for the structure of a photodissociation region
(PDR) in a cloud of finite size that is bathed in an external dissociating
radiation field. Our solution extends previous work, which with few exceptions
has been restricted to a one-dimensional treatment of the radiation field. We
show that our analytic results compare favorably to exact numerical
calculations in the one-dimensional limit. However, our more general geometry
provides a more realistic representation than a semi-infinite slab for
atomic-molecular complexes exposed to the interstellar radiation field,
particularly in environments such as low-metallicity dwarf galaxies where the
curvature and finite size of the atomic envelope cannot be neglected. For
clouds that are at least 20% molecular we obtain analytic expressions for the
molecular fraction in terms of properties of the gas and radiation field that
are accurate to tens of percent, while for clouds of lower molecular content we
obtain upper limits. As a side benefit, our analysis helps clarify when
self-shielding is the dominant process in H_2 formation, and under what
circumstances shielding by dust makes a significant contribution.


title:
Variability-selected active galactic nuclei from supernova search in the
  Chandra deep field south

abstract:
  Variability is a property shared by virtually all active galactic nuclei
(AGNs), and was adopted as a criterion for their selection using data from
multi epoch surveys. Low Luminosity AGNs (LLAGNs) are contaminated by the light
of their host galaxies, and cannot therefore be detected by the usual colour
techniques. For this reason, their evolution in cosmic time is poorly known.
Consistency with the evolution derived from X-ray detected samples has not been
clearly established so far, also because the low luminosity population consists
of a mixture of different object types. LLAGNs can be detected by the nuclear
optical variability of extended objects. Several variability surveys have been,
or are being, conducted for the detection of supernovae (SNe). We propose to
re-analyse these SNe data using a variability criterion optimised for AGN
detection, to select a new AGN sample and study its properties. We analysed
images acquired with the wide field imager at the 2.2 m ESO/MPI telescope, in
the framework of the STRESS supernova survey. We selected the AXAF field
centred on the Chandra Deep Field South where, besides the deep X-ray survey,
various optical data exist, originating in the EIS and COMBO-17 photometric
surveys and the spectroscopic database of GOODS. We obtained a catalogue of 132
variable AGN candidates. Several of the candidates are X-ray sources. We
compare our results with an HST variability study of X-ray and IR detected
AGNs, finding consistent results. The relatively high fraction of confirmed
AGNs in our sample (60%) allowed us to extract a list of reliable AGN
candidates for spectroscopic follow-up observations.


title: Performability Aspects of the Atlas Vo; Using Lmbench Suite

abstract:
  The ATLAS Virtual Organization is grid's largest Virtual Organization which
is currently in full production stage. Hereby a case is being made that a user
working within that VO is going to face a wide spectrum of different systems,
whose heterogeneity is enough to count as "orders of magnitude" according to a
number of metrics; including integer/float operations, memory throughput
(STREAM) and communication latencies. Furthermore, the spread of performance
does not appear to follow any known distribution pattern, which is demonstrated
in graphs produced during May 2007 measurements. It is implied that the current
practice where either "all-WNs-are-equal" or, the alternative of SPEC-based
rating used by LCG/EGEE is an oversimplification which is inappropriate and
expensive from an operational point of view, therefore new techniques are
needed for optimal grid resources allocation.


title:
On the time variability of geometrically-thin black hole accretion disks
  I : the search for modes in simulated disks

abstract:
  We present a detailed temporal analysis of a set of hydrodynamic and
magnetohydrodynamic (MHD) simulations of geometrically-thin (h/r~0.05) black
hole accretion disks. The black hole potential is approximated by the
Paczynski-Wiita pseudo-Newtonian potential. In particular, we use our
simulations to critically assess two widely discussed models for high-frequency
quasi-periodic oscillations, global oscillation modes (diskoseismology) and
parametric resonance instabilities. We find that initially disturbed
hydrodynamic disks clearly display the trapped global g-mode oscillation
predicted by linear perturbation theory. In contrast, the sustained turbulence
produced in the simulated MHD disks by the magneto-rotational instability does
not excite these trapped g-modes. We cannot say at present whether the MHD
turbulence actively damps the hydrodynamic g-mode. Our simulated MHD disks also
fail to display any indications of a parametric resonance instability between
the vertical and radial epicyclic frequencies. On the other hand, we do see
characteristic frequencies at any given radius in the disk corresponding to
local acoustic waves. We also conduct a blind search for any quasi-periodic
oscillation in a proxy lightcurve based on the instantaneous mass accretion
rate of the black hole, and place an upper limit of 2% on the total power in
any such feature. We highlight the importance of correcting for secular changes
in the simulated accretion disk when performing temporal analyses.


title: A unique non-Landau/Fermi liquid in 2d for high Tc superconductivity

abstract:
  It is shown that the main features of the phase diagram for high Tc
superconductivity can be calculated as a function of doping in a simple,
essentially unique non-Landau/Fermi liquid with quartic interactions. The phase
diagram depends on a single parameter 0<gamma<1 determined by the strength of
the interaction at short distances. A new d-wave gap equation has solutions
that fall under a superconducting dome, which terminates at the renormalization
group fixed point. Optimal doping is estimated to occur just below 3/2 \pi^2.
The overall scale for Tc is set by the recently measured universal nodal Fermi
velocity and lattice spacing, and is estimated to be 120K < Tc < 160K for
LaSrCuO.


title:
Very Broad [O III]4959,5007 Emission from the NGC 4472 Globular Cluster
  RZ2109 and Implications for the Mass of Its Black Hole X-ray Source

abstract:
  We present Keck LRIS spectroscopy of the black hole-hosting globular cluster
RZ2109 in the Virgo elliptical galaxy NGC 4472. We find that this object has
extraordinarily broad [OIII]5007 and [OIII]4959 emission lines, with velocity
widths of approximately 2,000 k/ms. This result has significant implications
for the nature of this accreting black-hole system and the mass of the globular
cluster black hole. We show that the broad [OIII]5007 emission must arise from
material driven at high velocity from the black hole system. This is because
the volume available near the black hole is too small by many orders of
magnitude to have enough [OIII] emitting atoms to account for the observed
L([OIII]5007) at high velocities, even if this volume is filled with Oxygen at
the critical density for [OIII]5007. The Balmer emission is also weak,
indicating the observed [OIII] is not due to shocks. We therefore conclude that
the [OIII]4959,5007 is produced by photoionization of material driven across
the cluster. The only known way to drive significant material at high velocity
is for a system accreting mass near or above its Eddington limit, which
indicates a stellar mass black hole. Since it is dynamically implausible to
form an accreting stellar mass black hole system in a globular cluster with an
intermediate mass black hole (IMBH), it appears this massive globular cluster
does not have an IMBH. We discuss further tests of this conclusion, and its
implications for the M_BH - M_stellar and M_BH - sigma relations.


title: The Araucaria Project: VLT-spectroscopy of blue massive stars in NGC 55

abstract:
  This is the first paper of a series devoted to studying the population of
blue massive stars in NGC 55, a galaxy of the Sculptor group at a distance of
about 2 Mpc. We have obtained optical (3300-6210A) low-resolution spectra of
blue massive stars with VLT-FORS2, which we have classified with the aid of
Milky Way and Magellanic Cloud standard stars.
  We have developed the first census of massive blue stars in NGC 55. A study
of stellar radial velocities shows agreement with existing HI rotational
velocity curve work and reveals the presence of one object with peculiar
velocity. A qualitative study of the stellar metallicity suggests that its
global distribution over NGC 55 is close to that of the LMC, as derived from
previous studies. We present a catalogue with 164 classifications of blue
massive stars in NGC 55. This catalogue is a first and necessary step for the
subsequent quantitative study of blue massive stars in NGC 55 with
state-of-the-art models.


title: Identifying stellar streams in the 1st RAVE public data release

abstract:
  We searched for and detected stellar streams or moving groups in the solar
neighbourhood, using the data provided by the 1st RAVE public data release.
This analysis is based on distances to RAVE stars estimated from a
color-magnitude relation that was calibrated on Hipparcos stars. Our final
sample consists of 7015 stars selected to be within 500 pc of the Sun and to
have distance errors better than 25%. Together with radial velocities from RAVE
and proper motions from various data bases, there are estimates for all 6
phase-space coordinates of the stars in the sample. We characterize the orbits
of these stars through suitable proxies for their angular momentum and
eccentricity, and compare the observed distribution to the expectations from a
smooth distribution. On this basis we identify at least four "phase space
overdensities" of stars on very similar orbits in the Solar neighbourhood. We
estimate the statistical significance of these overdensities by Monte Carlo
simulations. Three of them have been identified previously: the Sirius and
Hercules moving group and a stream found independently in 2006 by Arifyanto and
Fuchs and Helmi et al. In addition, we have found a new stream candidate on a
quite radial orbit, suggesting an origin external to the Milky Way's disk.
Also, there is evidence for the Arcturus stream and the Hyades-Pleiades moving
group in the sample. This analysis, using only a minute fraction of the final
RAVE data set, shows the power of this experiment to probe the phase-space
substructure of stars around the Sun.


title: A Mesoscopic Quantum Gravity Effect

abstract:
  We explore the symmetry reduced form of a non-perturbative solution to the
constraints of quantum gravity corresponding to quantum de Sitter space. The
system has a remarkably precise analogy with the non-relativistic formulation
of a particle falling in a constant gravitational field that we exploit in our
anaylsis. We find that the solution reduces to de Sitter space in the
semi-classical limit, but the uniquely quantum features of the solution have
peculiar property. Namely, the unambiguous quantum structures are neither of
Planck scale nor of cosmological scale. Instead, we find a periodicity in the
volume of the universe whose period, using the observed value of the
cosmological constant, is on the order of the volume of the proton.


title: Numerical Object Oriented Quantum Field Theory Calculations

abstract:
  The qft++ package is a library of C++ classes that facilitate numerical (not
algebraic) quantum field theory calculations. Mathematical objects such as
matrices, tensors, Dirac spinors, polarization and orbital angular momentum
tensors, etc. are represented as C++ objects in qft++. The package permits
construction of code which closely resembles quantum field theory expressions,
allowing for quick and reliable calculations.