title: Gamma-ray burst detection with the AGILE mini-calorimeter

abstract:
  The Mini-Calorimeter (MCAL) instrument on-board the AGILE satellite is a
non-imaging gamma-ray scintillation detector sensitive in the 300keV-100MeV
energy range with a total on-axis geometrical area of 1400cm^2. Gamma-Ray
Bursts (GRBs) are one of the main scientific targets of the AGILE mission and
the MCAL design as an independent self-triggering detector makes it a valuable
all-sky monitor for GRBs. Furthermore MCAL is one of the very few operative
instruments with microsecond timing capabilities in the MeV range. In this
paper the results of GRB detections with MCAL after one year of operation in
space are presented and discussed. A flexible trigger logic implemented in the
AGILE payload data-handling unit allows the on-board detection of GRBs. For
triggered events, energy and timing information are sent to telemetry on a
photon-by-photon basis, so that energy and time binning are limited by counting
statistics only. When the trigger logic is not active, GRBs can be detected
offline in ratemeter data, although with worse energy and time resolution.
Between the end of June 2007 and June 2008 MCAL detected 51 GRBs, with a
detection rate of about 1 GRB/week, plus several other events at a few
milliseconds timescales. Since February 2008 the on-board trigger logic has
been fully active. Comparison of MCAL detected events and data provided by
other space instruments confirms the sensitivity and effective area
estimations. MCAL also joined the 3rd Inter-Planetary Network, to contribute to
GRB localization by means of triangulation.


title:
Multilevel Discretized Random Field Models with "Spin" Correlations for
  the Simulation of Environmental Spatial Data

abstract:
  A problem of practical significance is the analysis of large, spatially
distributed data sets. The problem is more challenging for variables that
follow non-Gaussian distributions. We show that the spatial correlations
between variables can be captured by interactions between "spins". The spins
represent multilevel discretizations of the initial field with respect to a
number of pre-defined thresholds. The spatial dependence between the "spins" is
imposed by means of short-range interactions. We present two approaches,
inspired by the Ising and Potts models, that generate conditional simulations
from samples with missing data. The simulations of the "spin system" are forced
to respect locally the sample values and the system statistics globally. We
compare the two approaches in terms of their ability to reproduce the sample
statistical properties, to predict data at unsampled locations, as well as in
terms of their computational complexity. We discuss the impact of relevant
simulation parameters, such as the domain size, the number of discretization
levels, and the initial conditions.


title: Stein Spaces Characterized by their Endomorphisms

abstract:
  Finite dimensional Stein spaces admitting a proper holomorphic embedding of
the complex line are characterized, among all complex spaces, by their
holomorphic endomorphism semigroup in the sense that any semigroup isomorphism
induces either a biholomorphic or an antibiholomorphic map between them.


title: Ultracold Feshbach Molecules

abstract:
  In this Chapter, we give an introduction into experiments with Feshbach
molecules and their applications. In particular, we discuss the various
creation and detection methods, and the internal-state manipulation of such
molecules. We highlight two topics, namely Feshbach molecules in the halo
regime and the application of Feshbach molecule to achieve ultracold gases of
molecules in the rovibrational ground state. Our illustrative examples are
mainly based on work performed at Innsbruck University.


title:
A remark on the structure of the Busemann representative of a polyconvex
  function

abstract:
  Let W be a polyconvex function defined on the 2 x 2 real matrices. The
Busemann representative f, say, of W is the largest possible convex
representative of W. Writing L for the set of affine functions on R^{5} such
that a(A, det A) is less than or equal to W(A) for all 2 x 2 real matrices A, f
can then be expressed as f(X) = sup {a(X): a lies in L}. This short note proves
the surprising result that f is in general strictly larger than the `natural'
convex representative g(X) = sup {a(X): a lies in L and a(A, det A)=W(A) for
some A}.


title: Low energy processes to distinguish among seesaw models

abstract:
  We consider the three basic seesaw scenarios (with fermionic singlets, scalar
triplets or fermionic triplets) and discuss their phenomenology, aside from
neutrino masses. We use the effective field theory approach and compare the
dimension-six operators characteristic of these models. We discuss the
possibility of having large dimension-six operators and small dimension-five
(small neutrino masses) without any fine-tuning, if the lepton number is
violated at a low energy scale. Finally, we discuss some peculiarities of the
phenomenology of the fermionic triplet seesaw model.


title: Heavy-light hadrons and their excitations

abstract:
  We study the excitations of hadrons containing a single heavy quark. We
present meson and baryon mass splittings and ratios of meson decay constants
resulting from quenched and dynamical two-flavor configurations. Light quarks
are simulated using the Chirally Improved (CI) lattice Dirac operator. The
heavy quark is approximated by a static propagator, appropriate for the $b$
quark on our lattices ($1/a \sim 1-2$ GeV). We also include some preliminary
calculations of the heavy-quark kinetic corrections to the states.


title:
A lower bound for the error term in Weyl's law for certain Heisenberg
  manifolds

abstract:
  This article provides an Omega-result for the remainder term in Weyl's law
for the spectral counting function of certain (2l+1)-dimensional Heisenberg
manifolds.


title:
On one-homogeneous solutions to elliptic systems with spatial variable
  dependence in two dimensions

abstract:
  We extend the result of D. Phillips (On one-homogeneous solutions to elliptic
systems in two dimensions. C. R. Math. Acad. Sci. Paris 335 (2002), no. 1,
39-42) by showing that one-homogeneous solutions of certain elliptic systems in
divergence form either do not exist or must be affine. The result is novel in
two ways. Firstly, the system is allowed to depend (in a sufficiently smooth
way) on the spatial variable x. Secondly, Phillips's original result is shown
to apply to one-homogeneous solutions belonging to the Sobolev space H^{1},
from which his treatment of Lipschitz solutions follows as a special case. A
singular one-homogeneous solution to an elliptic system violating the
hypotheses of the main theorem is constructed using a variational method which
has links to nonlinear elasticity.


title: Observing the First Stars and Black Holes

abstract:
  The high sensitivity of JWST will open a new window on the end of the
cosmological dark ages. Small stellar clusters, with a stellar mass of several
10^6 M_sun, and low-mass black holes (BHs), with a mass of several 10^5 M_sun
should be directly detectable out to redshift z=10, and individual supernovae
(SNe) and gamma ray burst (GRB) afterglows are bright enough to be visible
beyond this redshift. Dense primordial gas, in the process of collapsing from
large scales to form protogalaxies, may also be possible to image through
diffuse recombination line emission, possibly even before stars or BHs are
formed. In this article, I discuss the key physical processes that are expected
to have determined the sizes of the first star-clusters and black holes, and
the prospect of studying these objects by direct detections with JWST and with
other instruments. The direct light emitted by the very first stellar clusters
and intermediate-mass black holes at z>10 will likely fall below JWST's
detection threshold. However, JWST could reveal a decline at the faint-end of
the high-redshift luminosity function, and thereby shed light on radiative and
other feedback effects that operate at these early epochs. JWST will also have
the sensitivity to detect individual SNe from beyond z=10. In a dedicated
survey lasting for several weeks, thousands of SNe could be detected at z>6,
with a redshift distribution extending to the formation of the very first stars
at z>15. Using these SNe as tracers may be the only method to map out the
earliest stages of the cosmic star-formation history. Finally, we point out
that studying the earliest objects at high redshift will also offer a new
window on the primordial power spectrum, on 100 times smaller scales than
probed by current large-scale structure data.


title:
Spin(7) instantons and the Hodge Conjecture for certain abelian
  four-folds: a modest proposal

abstract:
  The Hodge Conjecture is equivalent to a statement about conditions under
which a complex vector bundle on a smooth complex projective variety admits a
holomorphic structure. I advertise a class of abelian four-folds due to Mumford
where this approach could be tested. I construct explicit smooth vector bundles
- which can in fact be constructed in terms of of smooth line bundles - whose
Chern characters are given Hodge classes. An instanton connection on these
vector bundles would endow them with a holomorphic structure and thus prove
that these classes are algebraic. I use complex multiplication to exhibit
Cayley cycles representing the given Hodge classes. I find alternate complex
structures with respect to which the given bundles are holomorphic, and close
with a suggestion (due to G. Tian) as to how this may possibly be put to use.


title:
Efficient Long-distance Quantum Communication Using Microtoroidal
  Resonators

abstract:
  Based on the interaction between a three-level system and a microtoroidal
resonator, we present a scheme for long-distance quantum communication in which
entanglement generation with near 0.5 success probability and swaps can be
implemented by accurate state detection via measuring about 100 photons. With
this scheme the average time of successful entanglement distribution over 2500
km with high fidelity can be decreased to only about 30 ms, by 7 orders of
magnitude smaller compared with famous Duan-Lukin-Cirac-Zoller (DLCZ) protocol
[L.-M. Duan {\it et al.} Nature (London) {\bf414}, 413 (2001)].


title: Dominance, Intimidation, and `Choking' on the PGA Tour

abstract:
  Extending the work of Connolly and Rendleman (2008), we document the
dominance of Tiger Woods during the 1998-2001 PGA Tour seasons. We show that by
playing "average," Woods could have won some tournaments and placed no worse
than fourth in the tournaments in which he participated in year 2000, his best
on the PGA Tour. No other PGA Tour player in our sample could have come close
to such a feat. We also are able to quantify the intimidation factor associated
with playing with Woods. On average, players who were paired with Woods during
the 1998-2001 period scored 0.462 strokes per round worse than normal. Although
we find that Woods' presence in a tournament may have had a small, but
statistically significant adverse impact on the entire field, this effect was
swamped by the apparent intimidation factor associated with having to play with
Tiger side-by-side.
  We also demonstrate that Phil Mickelson's performance in major golf
championships over the 1998-2001 period was not nearly as bad as was frequently
mentioned in the golf press. Although Mickelson won no majors during this
period, he played sufficiently well to have won one or two majors under normal
circumstances. Moreover, his overall performance in majors, relative to his
estimated skill level, was comparable to that of Tiger Woods, who won five of
16 major golf championships during our four-year sample period. Thus, the
general characterization of Woods as golf's dominant player over the 1998-2001
period was accurate, but the frequent characterization of Phil Mickelson
choking in majors was not.


title: Search for a Higgs Boson Decaying to Two W Bosons at CDF

abstract:
  We present a search for a Higgs boson decaying to two W bosons in ppbar
collisions at sqrt(s)=1.96 TeV center-of-mass energy. The data sample
corresponds to an integrated luminosity of 3.0 fb-1 collected with the CDF II
detector. We find no evidence for production of a Higgs boson with mass between
110 and 200 GeV/c^2, and determine upper limits on the production cross
section. For the mass of 160 GeV/c^2, where the analysis is most sensitive, the
observed (expected) limit is 0.7 pb (0.9 pb) at 95% Bayesian credibility level
which is 1.7 (2.2) times the standard model cross section.


title:
A collimated, ionized bipolar structure and a high density torus in the
  young planetary nebula IRAS 17347-3139

abstract:
  We present observations of continuum (lambda = 0.7, 1.3, 3.6 and 18 cm) and
OH maser (lambda = 18 cm) emission toward the young planetary nebula IRAS
17347-3139, which is one of the three planetary nebulae that are known to
harbor water maser emission. From the continuum observations we show that the
ionized shell of IRAS 17347-3139 consists of two main structures: one extended
(size ~1". 5) with bipolar morphology along PA=-30 degrees, elongated in the
same direction as the lobes observed in the near-infrared images, and a central
compact structure (size ~0". 25) elongated in the direction perpendicular to
the bipolar axis, coinciding with the equatorial dark lane observed in the
near-infrared images. Our image at 1.3 cm suggests the presence of dense walls
in the ionized bipolar lobes. We estimate for the central compact structure a
value of the electron density at least ~5 times higher than in the lobes. A
high resolution image of this structure at 0.7 cm shows two peaks separated by
about 0". 13 (corresponding to 100-780 AU, using a distance range of 0.8-6
kpc). This emission is interpreted as originating in an ionized equatorial
torus-like structure, from whose edges the water maser emission might be
arising. We have detected weak OH 1612 MHz maser emission at VLSR ~ -70 km/s
associated with IRAS 17347-3139. We derive a 3 sigma upper limit of < 35% for
the percentage of circularly polarized emission. Within our primary beam, we
detected additional OH 1612 MHz maser emission in the LSR velocity ranges -5 to
-24 and -90 to -123 km/s, associated with the sources 2MASS J17380406-3138387
and OH 356.65-0.15, respectively.


title: Thermal Right-Handed Sneutrino Dark Matter

abstract:
  We discuss the relic abundance of the right-handed sneutrinos in the
supersymmetric F_D-term model of hybrid inflation. As well as providing a
natural solution to the mu- and gravitino overabundance problems, the model
offers the lightest right-handed sneutrino as a candidate for thermal dark
matter. The F_D-term model predicts a new quartic coupling of purely
right-handed sneutrinos to the Higgs doublets that thermalizes the sneutrinos
and makes them annihilate sufficiently fast to a level compatible with the
current cosmic microwave background data. We discuss this scenario and identify
favourable regions of the parameter space within mSUGRA.


title:
Renormalized Polyakov loops in various representations in finite
  temperature SU(2) gauge theory

abstract:
  We present results for the renormalized Polyakov loop in the three lowest
irreducible representations of SU(2) gauge theory at finite temperature. We
will discuss their scaling behavior near $T_c$ and test Casimir scaling in the
deconfined phase. Moreover, we will compare these results to calculations for
the renormalized Polyakov loops in several representations in the SU(3) gauge
theory.


title:
Three dimensional filamentary structures of a relativistic electron beam
  in Fast Ignition plasmas

abstract:
  The filamentary structures and associated electromagnetic fields of a
relativistic electron beam have been studied by three dimensional
particle-in-cell (PIC) simulations in the context of Fast Ignition fusion. The
simulations explicitly include collisions in return plasma current and
distinctly examine the effects of beam temperature and collisions on the growth
of filamentary structures generated.


title: Characterizing graphs with convex and connected configuration spaces

abstract:
  We define and study exact, efficient representations of realization spaces
Euclidean Distance Constraint Systems (EDCS), which includes Linkages and
Frameworks. Each representation corresponds to a choice of Cayley parameters
and yields a different parametrized configuration space. Significantly, we give
purely graph-theoretic, forbidden minor characterizations that capture (i) the
class of graphs that always admit efficient configuration spaces and (ii) the
possible choices of representation parameters that yield efficient
configuration spaces for a given graph. In addition, our results are tight: we
show counterexamples to obvious extensions. This is the first step in a
systematic and graded program of combinatorial characterizations of efficient
configuration spaces. We discuss several future theoretical and applied
research directions. Some of our proofs employ an unusual interplay of (a)
classical analytic results related to positive semi-definiteness of Euclidean
distance matrices, with (b) recent forbidden minor characterizations and
algorithms related to the notion of d-realizability of EDCS. We further
introduce a novel type of restricted edge contraction or reduction to a graph
minor, a "trick" that we anticipate will be useful in other situations.


title: Semistable principal Higgs bundles

abstract:
  We give a Miyaoka-type semistability criterion for principal Higgs G-bundles
E on complex projective manifolds of any dimension, i.e., we prove that E is
semistable and the second Chern class of its adjoint bundle vanishes if and
only if certain line bundles, obtained from the characters of the parabolic
subgroups of G, are numerically effective. We also give alternative
characterizations in terms of a notion of numerical effectiveness of Higgs
vector bundles we have recently introduced.


title:
Inhomogeneous Diophantine approximation on curves and Hausdorff
  dimension

abstract:
  The goal of this paper is to develop a coherent theory for inhomogeneous
Diophantine approximation on curves in $R^n$ akin to the well established
homogeneous theory. More specifically, the measure theoretic results obtained
generalize the fundamental homogeneous theorems of R.C. Baker (1978), Dodson,
Dickinson (2000) and Beresnevich, Bernik, Kleinbock, Margulis (2002). In the
case of planar curves, the complete Hausdorff dimension theory is developed


title: DNA nano-mechanics: how proteins deform the double helix

abstract:
  It is a standard exercise in mechanical engineering to infer the external
forces and torques on a body from its static shape and known elastic
properties. Here we apply this kind of analysis to distorted double-helical DNA
in complexes with proteins. We extract the local mean forces and torques acting
on each base-pair of bound DNA from high-resolution complex structures. Our
method relies on known elastic potentials and a careful choice of coordinates
of the well-established rigid base-pair model of DNA. The results are robust
with respect to parameter and conformation uncertainty. They reveal the complex
nano-mechanical patterns of interaction between proteins and DNA. Being
non-trivially and non-locally related to observed DNA conformations, base-pair
forces and torques provide a new view on DNA-protein binding that complements
structural analysis.


title:
Probing the Galactic Bulge with deep Adaptive Optics imaging: the age of
  NGC 6440

abstract:
  We present first results of a pilot project aimed at exploiting the
potentiality of ground based adaptive optics imaging in the near infrared to
determine the age of stellar clusters in the Galactic Bulge. We have used a
combination of high resolution adaptive optics (ESO-VLT NAOS-CONICA) and
wide-field (ESO-NTT-SOFI) photometry of the metal rich globular cluster NGC
6440 located towards the inner Bulge, to compute a deep color magnitude diagram
from the tip of the Red Giant Branch down to J~22$, two magnitudes below the
Main Sequence Turn Off (TO). The magnitude difference between the TO level and
the red Horizontal Branch has been used as an age indicator. It is the first
time that such a measurement for a bulge globular cluster has been obtained
with a ground based telescope. From a direct comparison with 47 Tuc and with a
set of theoretical isochrones, we concluded that NGC 6440 is old and likely
coeval to 47 Tuc. This result adds a new evidence that the Galactic Bulge is ~2
Gyr younger at most than the pristine, metal poor population of the Galactic
Halo.


title: UHECRs from the Radio Lobes of AGNs

abstract:
  We report a stochastic mechanism of particle acceleration from first
principles in an environment having properties like those of Radio Lobes in
AGNs. We show that energies $\sim 10^{20}$ eV are reached in $\sim 10^6$ years
for protons. Our results reopen the question regarding the nature of the
high-energy cutoff in the observed spectrum: whether it is due solely to
propagation effects, or whether it is also affected by the maximum energy
permitted by the acceleration process itself.


title:
A variational principle for topological pressure for certain non-compact
  sets

abstract:
  Let $(X,d)$ be a compact metric space, $f:X \mapsto X$ be a continuous map
with the specification property, and $\varphi: X \mapsto \IR$ be a continuous
function. We prove a variational principle for topological pressure (in the
sense of Pesin and Pitskel) for non-compact sets of the form \[ \{x \in X :
\lim_{n \ra \infty} \frac{1}{n} \sum_{i = 0}^{n-1} \varphi (f^i (x)) = \alpha
\}. \] Analogous results were previously known for topological entropy. As an
application, we prove multifractal analysis results for the entropy spectrum of
a suspension flow over a continuous map with specification and the dimension
spectrum of certain non-uniformly expanding interval maps.


title:
A Reconfigurable Programmable Logic Block for a Multi-Style Asynchronous
  FPGA resistant to Side-Channel Attacks

abstract:
  Side-channel attacks are efficient attacks against cryptographic devices.
They use only quantities observable from outside, such as the duration and the
power consumption. Attacks against synchronous devices using electric
observations are facilitated by the fact that all transitions occur
simultaneously with some global clock signal. Asynchronous control remove this
synchronization and therefore makes it more difficult for the attacker to
insulate \emph{interesting intervals}. In addition the coding of data in an
asynchronous circuit is inherently more difficult to attack. This article
describes the Programmable Logic Block of an asynchronous FPGA resistant
against \emph{side-channel attacks}. Additionally it can implement different
styles of asynchronous control and of data representation.


title: Search for Chiral Fermion Actions on Non-Orthogonal Lattices

abstract:
  The graphene-inspired fermion actions recently proposed by Creutz and Borici
have sparked interest in the use of non-orthogonal lattices in lattice QCD.
These fermion actions have the desired chiral symmetry and have the minimal
doubling required by the Nielsen-Ninomiya no-go theorem. However, due to the
lack of discrete symmetries, radiative corrections in the gauged lattice theory
will lead to the generation of unwanted relevant and marginal operators. Other
similarly motivated non-orthogonal fermion actions avoid these unwanted
operators, but introduce incorrect continuum behavior or excessive fermion
doubling. A delicate balance of symmetry is required for chiral symmetry,
minimal doubling, and no relevant operators, and to date, no non-orthogonal
lattice action has accomplished this balance.


title: Solving non-abelian loop Toda equations

abstract:
  We construct soliton solutions for non-abelian loop Toda equations associated
with general linear groups. Here we consider the untwisted case only and use
the rational dressing method based upon appropriate block-matrix representation
suggested by the initial $\bbZ$-gradation.


title:
Linearized model Fokker-Planck collision operators for gyrokinetic
  simulations. II. Numerical implementation and tests

abstract:
  A set of key properties for an ideal dissipation scheme in gyrokinetic
simulations is proposed, and implementation of a model collision operator
satisfying these properties is described. This operator is based on the exact
linearized test-particle collision operator, with approximations to the
field-particle terms that preserve conservation laws and an H-Theorem. It
includes energy diffusion, pitch-angle scattering, and finite Larmor radius
effects corresponding to classical (real-space) diffusion. The numerical
implementation in the continuum gyrokinetic code GS2 is fully implicit and
guarantees exact satisfaction of conservation properties. Numerical results are
presented showing that the correct physics is captured over the entire range of
collisionalities, from the collisionless to the strongly collisional regimes,
without recourse to artificial dissipation.


title: Anisotropic Models of Dark Halos

abstract:
  An iterative approach is used to construct spherically symmetric equilibrium
models with an anisotropic velocity distribution. The potentialities of the
method have been tested on models with known distribution functions, the
Osipkov-Merritt models. It is shown that models that differ significantly from
the Osipkov-Merritt models can be constructed. An N-body model of a dark halo
with a density distribution that approximates the results of cosmological
simulations (the Navarro--Frenk--White model) has been constructed. The
anisotropy profile has been taken to be similar to that yielded by cosmological
simulations. The constructed models can serve as direct input data for
investigating the dynamics and stability of such systems in N-body simulations.


title:
The structure of the protoplanetary disk surrounding three young
  intermediate mass stars. II. Spatially resolved dust and gas distribution

abstract:
  [Abridged] We present the first direct comparison of the distribution of the
gas, as traced by the [OI] 6300 AA emission, and the dust, as traced by the 10
micron emission, in the protoplanetary disk around three intermediate-mass
stars: HD 101412, HD 135344 B and HD 179218. N-band visibilities were obtained
with VLTI/MIDI. Simple geometrical models are used to compare the dust emission
to high-resolution optical spectra in the 6300 AA [OI] line of the same
targets. The disks around HD 101412 and HD 135344 B appear strongly flared in
the gas, but self-shadowed in the dust beyond ~ 2 AU. In both systems, the 10
micron emission is rather compact (< 2 AU) while the [OI] brightness profile
shows a double peaked structure. The inner peak is strongest and is consistent
with the location of the dust, the outer peak is fainter and is located at 5-10
AU. Spatially extended PAH emission is found in both disks. The disk around HD
179218 is flared in the dust. The 10 micron emission emerges from a double
ring-like structure with the first ring peaking at ~ 1 AU and the second at ~
20 AU. No dust emission is detected between ~ 3 -- 15 AU. The oxygen emission
seems also to come from a flared structure, however, the bulk of this emission
is produced between ~ 1 -- 10 AU. This could indicate a lack of gas in the
outer disk or could be due to chemical effects which reduce the abundance of OH
-- the parent molecule of the observed [OI] emission -- further away from the
star. The three systems, HD 179218, HD 135344 B and HD 101412, may form an
evolutionary sequence: the disk initially flared becomes flat under the
combined action of gas-dust decoupling, grain growth and dust settling.


title: Symmetries of Spin Calogero Models

abstract:
  We investigate the symmetry algebras of integrable spin Calogero systems
constructed from Dunkl operators associated to finite Coxeter groups. Based on
two explicit examples, we show that the common view of associating one symmetry
algebra to a given Coxeter group $W$ is wrong. More precisely, the symmetry
algebra heavily depends on the representation of $W$ on the spins. We prove
this by identifying two different symmetry algebras for a $B_L$ spin Calogero
model and three for $G_2$ spin Calogero model. They are all related to the
half-loop algebra and its twisted versions. Some of the result are extended to
any finite Coxeter group.


title: CO Fundamental Emission from V836 Tau

abstract:
  We present high resolution 4.7 micron CO fundamental spectroscopy of V836
Tau, a young star with properties that are between those of classical and weak
T Tauri stars and which may be dissipating its circumstellar disk. We find that
the CO line profiles of V836 Tau are unusual in that they are markedly
double-peaked, even after correcting for stellar photospheric absorption in the
spectrum. This suggests that the CO emission arises from a restricted range of
disk radii (< 0.5 AU), in contrast to the situation for most classical T Tauri
stars where the CO emission extends out to much larger radii (~ 1-2 AU). We
discuss whether the outer radius of the emission in V836 Tau results from the
physical truncation of the disk or an excitation effect. We also explore how
either of these hypotheses may bear on our understanding of disk dissipation in
this system.


title:
Measurement of $\sigma(e^+e^-\to\pi^+\pi^-\gamma(\gamma))$ and the
  dipion contribution to the muon anomaly with the KLOE detector

abstract:
  We have measured the cross section
$\sigma(e^+e^-\to\pi^+\pi^-\gamma(\gamma))$ at DA$\Phi$NE, the Frascati
\phi-factory, using events with initial state radiation photons emitted at
small angle and inclusive of final state radiation. We present the analysis of
a new data set corresponding to an integrated luminosity of 240 pb$^{-1}$. We
have achieved a reduced systematic uncertainty with respect to previously
published KLOE results. From the cross section we obtain the pion form factor
and the contribution to the muon magnetic anomaly from two pion states in the
mass range $0.592 < M_{\pi\pi} < 0.975$ GeV. For the latter we find $\Delta
a^{\pi\pi}_\mu = (387.2\pm0.5_{\rm stat}\pm2.4_{\rm exp}\pm2.3_{\rm th})\times
10^{-10}$


title: Holographic Space-time from the Big Bang to the de Sitter era

abstract:
  I review the holographic theory of space-time and its applications to
cosmology. Much of this has appeared before, but the discussion is more unified
and concise. I also include some material on work in progress, whose aim is to
understand compactification in terms of finite dimensional super-algebras. This
is an expanded version of a lecture I gave at the conference on Liouville
Quantum Gravity and Statistical Systems, in memory of Alexei Zamolodchikov, at
the Poncelet Institute in Moscow, 21-24 June, 2008.


title:
Efficient Photometric Selection of Quasars from the Sloan Digital Sky
  Survey: II. ~1,000,000 Quasars from Data Release Six

abstract:
  We present a catalog of 1,172,157 quasar candidates selected from the
photometric imaging data of the Sloan Digital Sky Survey (SDSS). The objects
are all point sources to a limiting magnitude of i=21.3 from 8417 sq. deg. of
imaging from SDSS Data Release 6 (DR6). This sample extends our previous
catalog by using the latest SDSS public release data and probing both UV-excess
and high-redshift quasars. While the addition of high-redshift candidates
reduces the overall efficiency (quasars:quasar candidates) of the catalog to
~80%, it is expected to contain no fewer than 850,000 bona fide quasars -- ~8
times the number of our previous sample, and ~10 times the size of the largest
spectroscopic quasar catalog. Cross-matching between our photometric catalog
and spectroscopic quasar catalogs from both the SDSS and 2dF Surveys, yields
88,879 spectroscopically confirmed quasars. For judicious selection of the most
robust UV-excess sources (~500,000 objects in all), the efficiency is nearly
97% -- more than sufficient for detailed statistical analyses. The catalog's
completeness to type 1 (broad-line) quasars is expected to be no worse than
70%, with most missing objects occurring at z<0.7 and 2.5<z<3.0. In addition to
classification information, we provide photometric redshift estimates
(typically good to Delta z +/- 0.3 [2 sigma]) and cross-matching with radio,
X-ray, and proper motion catalogs. Finally, we consider the catalog's utility
for determining the optical luminosity function of quasars and are able to
confirm the flattening of the bright-end slope of the quasar luminosity
function at z~4 as compared to z~2.


title: Quantum Gravitational Effects and Grand Unification

abstract:
  In grand unified theories with large numbers of fields, renormalization
effects significantly modify the scale at which quantum gravity becomes strong.
This in turn can modify the boundary conditions for coupling constant
unification, if higher dimensional operators induced by gravity are taken into
consideration. We show that the generic size of, and the uncertainty in, these
effects from gravity can be larger than the two-loop corrections typically
considered in renormalization group analyses of unification. In some cases,
gravitational effects of modest size can render unification impossible.


title:
Spectral statistics of the quenched normal modes of a network-forming
  molecular liquid

abstract:
  We evaluate the density of states of the quenched normal modes of ST2 water,
and their statistical fluctuations, for a range of densities spanning three
regimes of behavior of a hydrogen bonded liquid: a lower-density regime of
random tetrahedral network formation; in the vicinity of a liquid-liquid
critical point; and in a higher-density regime of fragile glass-forming
behavior. For all cases we find that the fluctuations around the mean spectral
densities obey the predictions of the Gaussian orthogonal ensemble of random
matrix theory. We also measure the participation ratio of the normal modes
across the entire frequency range, and find behavior consistent with the
majority of modes being of an extended nature, rather than localized.


title:
J/psi dissociation by light mesons in an extended Nambu Jona-Lasinio
  model

abstract:
  An alternative model for the dissociation of the J/psi is proposed. Chiral
symmetry is properly implemented. Abnormal parity interactions and mesonic form
factors naturally arise from the underlying quark sub-structure. Analytic
confinement for the light quarks is generated by appropriately chosen the quark
interaction kernels. Dissociation cross sections of the J/psi by either a pion
or a rho meson are then evaluated and discussed.


title: Inclusive high Q2 cross sections and QCD and EW fits at HERA

abstract:
  The latest measurements of the cross sections for neutral and charged current
deep inelastic scattering in e+/-p collisions at HERA with longitudinally
polarised lepton beams are presented. The measured cross sections are compared
with the predictions of the Standard Model. Next-to-leading-order QCD analyses
of HERA data are also presented. The analyses yield the parton distribution
functions of the proton and are extended to also extract electroweak
parameters. The determinations from HERA are compared with those from LEP and
the Tevatron.


title: Bockstein theorem for nilpotent groups

abstract:
  We extend the definition of Bockstein basis $\sigma(G)$ to nilpotent groups
$G$. A metrizable space $X$ is called a {\it Bockstein space} if $\dim_G(X) =
\sup\{\dim_H(X) | H\in \sigma(G)\}$ for all Abelian groups $G$. Bockstein First
Theorem says that all compact spaces are Bockstein spaces.
  Here are the main results of the paper: Let $X$ be a Bockstein space. If $G$
is nilpotent, then $\dim_G(X) \leq 1$ if and only if $\sup\{\dim_H(X) |
H\in\sigma(G)\}\leq 1$.
  $X$ is a Bockstein space if and only if $\dim_{\Z_{(l)}} (X) =
\dim_{\hat{Z}_{(l)}}(X)$ for all subsets $l$ of prime numbers.


title: Tachyonic decay of unstable Dirichlet branes

abstract:
  We consider an unstable bound system of two supersymmetric Dirichlet branes
of different dimensionality ($p,p'$ with $p'<p$) embedded in a flat
non-compactified IIA or IIB type background. We study the decay, via tachyonic
condensation, of such unstable bound states leading to a pair of bound
D$(p-1)$, D$p'$-branes. We show that only when the gauge fields carried by the
D$p$-brane are localised perependicular to the tachyon direction, then tachyon
condensation will indeed take place. We perform our analysis by combining both,
the Hamiltonian and the Lagrangian approach.


title:
Gamma Ray Bursts and the Fermi Gamma Ray Space Telescope: Notes to the
  La Plata Lectures

abstract:
  Gamma-ray bursts (GRBs) are a mixed class of sources consisting of, at least,
the long duration and short-hard subclasses, the X-ray flashes, and the
low-luminosity GRBs. In all cases, the release of enormous amounts of energy on
a short timescale makes an energetic, relativistic or mildly relativistic
fireball that expands until it reaches a coasting Lorentz factor determined by
the amount of baryons mixed into the fireball. Radiation is produced when the
blast wave interacts with the surrounding medium at an external shock, or when
shell collisions dissipate kinetic energy at internal shocks. This series of
notes is organized as follows: (1) The observational situation of GRBs is
summarized; (2) Progenitor models of GRBs are described; (3) An overview of the
the blast-wave physics used to model leptonic emissions is given; (4) GRB
physics is applied to hadronic acceleration and ultra-high energy cosmic ray
production; (5) Prospects for GRB physics and gamma-ray astronomy with the
Fermi Gamma-ray Space Telescope (FGST, formerly GLAST), and space-based and
ground-based observatories are considered. Also included are exercises and
problems.


title: Formalising the pi-calculus using nominal logic

abstract:
  We formalise the pi-calculus using the nominal datatype package, based on
ideas from the nominal logic by Pitts et al., and demonstrate an implementation
in Isabelle/HOL. The purpose is to derive powerful induction rules for the
semantics in order to conduct machine checkable proofs, closely following the
intuitive arguments found in manual proofs. In this way we have covered many of
the standard theorems of bisimulation equivalence and congruence, both late and
early, and both strong and weak in a uniform manner. We thus provide one of the
most extensive formalisations of a process calculus ever done inside a theorem
prover.
  A significant gain in our formulation is that agents are identified up to
alpha-equivalence, thereby greatly reducing the arguments about bound names.
This is a normal strategy for manual proofs about the pi-calculus, but that
kind of hand waving has previously been difficult to incorporate smoothly in an
interactive theorem prover. We show how the nominal logic formalism and its
support in Isabelle accomplishes this and thus significantly reduces the tedium
of conducting completely formal proofs. This improves on previous work using
weak higher order abstract syntax since we do not need extra assumptions to
filter out exotic terms and can keep all arguments within a familiar
first-order logic.


title: Metastable Aspects of Singlet Extended Higgs Models

abstract:
  It has long been known that the broken supersymmetric (susy) phase of the
singlet extended susy higgs model (SESHM) is at best metastable and the ground
states of the model have vanishing vacuum energy and are exactly
supersymmetric. If the SESHM is confirmed at the Large Hadron Collider (LHC),
the numerical values of the parameters of the model have a bearing on key
properties of the susy phase and might provide an estimate of the remaining
time before a possible decay of our false vacuum. We provide some analysis of
the model including a treatment of phases in the potential and soft higgs
masses.


title: Comments on Background Independence and Gauge Redundancies

abstract:
  We describe the definition and the role background independence and the
closely related notion of diffeomorphism invariance play in modern string
theory. These important concepts are transformed by a new understanding of
gauge redundancies and their implementation in non-perturbative quantum field
theory and quantum gravity. This new understanding also suggests a new role for
the so-called background-independent approaches to directly quantize the
gravitational field. This article is intended for a general audience, and is
based on a plenary talk given in the Loops 2007 conference in Morelia, Mexico.


title: Remarks on Kahler Ricci Flow

abstract:
  We study some estimates along the Kahler Ricci flow on Fano manifolds. Using
these estimates, we show the convergence of Kahler Ricci flow directly if the
$\alpha$-invariant of the canonical class is greater than $\frac{n}{n+1}$.
Applying these convergence theorems, we can give a flow proof of Calabi
conjecture on such Fano manifolds. In particular, the existence of Kahler
Einstein metrics on a lot of Fano surfaces can be proved by flow method. Note
that this geometric conclusion (based on the same assumption) was established
earlier via elliptic method by G. Tian. However, a new proof based on Kahler
Ricci flow should be still interesting in its own right.


title:
Exotic phases of finite temperature SU(N) gauge theories with massive
  fermions: F, Adj, A/S

abstract:
  The phase diagrams at high temperature of SU(N) gauge theories with massive
fermions are calculated by numerically minimizing the one-loop effective
potential. We consider fermions in the Fundamental (F), Adjoint (Adj),
Antisymmetric (AS), and Symmetric (S) representations, for N from 3 to 9, with
periodic and antiperiodic boundary conditions applied. For one flavour of AS/S
(Dirac) fermion with periodic boundary conditions the C-breaking phase is
favoured perturbatively for all values of the fermion mass. In the case of one
flavour of adjoint Majorana fermion, and periodic boundary conditons, the
deconfined phase is favoured for any fermion mass. For one or more adjoint
Dirac fermion (two or more Majorana fermions) we find partially-confining
phases as well as new phases with unusual properties. Our results for SU(3) and
SU(4) are consistent with our lattice simulations of a related model.


title:
Centimeter-wave continuum radiation from the rho Ophiuchi molecular
  cloud

abstract:
  The rho Oph molecular cloud is undergoing intermediate-mass star formation.
UV radiation from its hottest young stars heats and dissociates exposed layers,
but does not ionize hydrogen. Only faint radiation from the Rayleigh-Jeans tail
of ~10-100K dust is expected at wavelengths longwards of 3mm. Yet Cosmic
Background Imager (CBI) observations reveal that the rho Oph W
photo-dissociation region (PDR) is surprisingly bright at centimetre
wavelengths. We searched for interpretations consistent with the WMAP radio
spectrum, new ISO-LWS parallel mode images and archival Spitzer data.
Dust-related emission mechanisms at 1 cm, as proposed by Draine & Lazarian, are
a possibility. But a magnetic enhancement of the grain opacity at 1cm is
inconsistent with the morphology of the dust column maps Nd and the lack of
detected polarization. Spinning dust, or electric-dipole radiation from
spinning very small grains (VSGs), comfortably explains the radio spectrum,
although not the conspicuous absence from the CBI data of the infrared
circumstellar nebulae around the B-type stars S1 and SR~3. Allowing for VSG
depletion can marginally reconcile spinning dust with the data. As an
alternative interpretation we consider the continuum from residual charges in
rho Oph W, where most of carbon should be photoionised by the close binary
HD147889 (B2IV, B3IV). Electron densities of ~100 cm^{-3}, or H-nucleus
densities n_H > 1E6 cm^{-3}, are required to interpret rho Oph W as the CII
Stromgren sphere of HD147889. However the observed steep and positive
low-frequency spectral index would then require optically thick emission from
an hitherto unobserved ensemble of dense clumps or sheets with a filling factor
~1E-4 and n_H ~ 1E7 cm^{-3}.


title:
Test of the Additivity Principle for Current Fluctuations in a Model of
  Heat Conduction

abstract:
  The additivity principle allows to compute the current distribution in many
one-dimensional (1D) nonequilibrium systems. Using simulations, we confirm this
conjecture in the 1D Kipnis-Marchioro-Presutti model of heat conduction for a
wide current interval. The current distribution shows both Gaussian and
non-Gaussian regimes, and obeys the Gallavotti-Cohen fluctuation theorem. We
verify the existence of a well-defined temperature profile associated to a
given current fluctuation. This profile is independent of the sign of the
current, and this symmetry extends to higher-order profiles and spatial
correlations. We also show that finite-time joint fluctuations of the current
and the profile are described by the additivity functional. These results
suggest the additivity hypothesis as a general and powerful tool to compute
current distributions in many nonequilibrium systems.


title: On the derivation of Fourier's law in stochastic energy exchange systems

abstract:
  We present a detailed derivation of Fourier's law in a class of stochastic
energy exchange systems that naturally characterize two-dimensional mechanical
systems of locally confined particles in interaction. The stochastic systems
consist of an array of energy variables which can be partially exchanged among
nearest neighbours at variable rates. We provide two independent derivations of
the thermal conductivity and prove this quantity is identical to the frequency
of energy exchanges. The first derivation relies on the diffusion of the
Helfand moment, which is determined solely by static averages. The second
approach relies on a gradient expansion of the probability measure around a
non-equilibrium stationary state. The linear part of the heat current is
determined by local thermal equilibrium distributions which solve a
Boltzmann-like equation. A numerical scheme is presented with computations of
the conductivity along our two methods. The results are in excellent agreement
with our theory.


title:
First 450-micron dust continuum mapping of the massive star-forming
  region NGC 3576 with the P-ArTeMiS bolometer camera

abstract:
  Context: The earliest phases of massive star formation are currently much
debated. Aims. In an effort to make progress, we took a census of Class0-like
protostellar dense cores in the NGC 3576 region, one of the nearest and most
luminous embedded sites of high-mass star formation in the Galaxy. Methods: We
used the P-ArTeMiS bolometer camera on the APEX telescope to produce the first
450-micron dust continuum map of the filamentary dense clump associated with
NGC 3576. Results: Combining our 450-micron observations with existing data at
other wavelengths, we have identified seven massive protostellar sources along
the NGC 3576 filament and placed them in the M_env - L_bol evolutionary diagram
for protostars. Conclusions: Comparison with theoretical evolutionary tracks
suggests that these seven protostellar sources will evolve into massive stars
with masses M* ~ 15-50 Msun. Four sources are classified as candidate high-mass
Class 0 objects, two sources as massive Class I objects, and one source appears
to be at an intermediate stage.


title: Integral Field Spectroscopy of HH 262: The Spectral Atlas

abstract:
  HH 262 is a group of emitting knots displaying an "hour-glass" morphology in
the Halpha and [SII] lines, located 3.5' to the northeast of the young stellar
object L1551-IRS5, in Taurus. We present new results of the kinematics and
physical conditions of HH 262 based on Integral Field Spectroscopy covering a
field of 1.5'x3', which includes all the bright knots in HH 262. These data
show complex kinematics and significant variations in physical conditions over
the mapped region of HH 262 on a spatial scale of <3". A new result derived
from the IFS data is the weakness of the [NII] emission (below detection limit
in most of the mapped region of HH 262), including the brightest central knots.
Our data reinforce the association of HH 262 with the redshifted lobe of the
evolved molecular outflow L1551-IRS5. The interaction of this outflow with a
younger one, powered by L1551 NE, around the position of HH 262 could give rise
to the complex morphology and kinematics of HH 262.


title:
On the Christoffel-Darboux kernel for random Hermitian matrices with
  external source

abstract:
  Bleher and Kuijlaars, and Daems and Kuijlaars showed that the correlation
functions of the eigenvalues of a random matrix from unitary ensemble with
external source can be expressed in terms of the Christoffel-Darboux kernel for
multiple orthogonal polynomials. We obtain a representation of this
Christoffel-Darboux kernel in terms of the usual orthogonal polynomials.


title: Geometric idealizers

abstract:
  Let X be a projective variety, $\sigma$ an automorphism of X, L a
$\sigma$-ample invertible sheaf on X, and Z a closed subscheme of X. Inside the
twisted homogeneous coordinate ring $B = B(X, L, \sigma)$, let I be the right
ideal of sections vanishing at Z. We study the subring R = k + I of B. Under
mild conditions on Z and $\sigma$, R is the idealizer of I in B: the maximal
subring of B in which I is a two-sided ideal.
  We give geometric conditions on Z and $\sigma$ that determine the algebraic
properties of R, and show that if Z and $\sigma$ are sufficiently general, in a
sense we make precise, then R is left and right noetherian, has finite left and
right cohomological dimension, is strongly right noetherian but not strongly
left noetherian, and satisfies right $\chi_d$ (where d = \codim Z) but fails
left $\chi_1$. We also give an example of a right noetherian ring with infinite
right cohomological dimension, partially answering a question of Stafford and
Van den Bergh. This generalizes results of Rogalski in the case that Z is a
point in $\mathbb{P}^d$.


title: Superadditivity of communication capacity using entangled inputs

abstract:
  The design of error-correcting codes used in modern communications relies on
information theory to quantify the capacity of a noisy channel to send
information [1]. This capacity can be expressed using the mutual information
between input and output for a single use of the channel: although correlations
between subsequent input bits are used to correct errors, they cannot increase
the capacity. For quantum channels, it has been an open question whether
entangled input states can increase the capacity to send classical information
[2]. The additivity conjecture [3,4] states that entanglement does not help,
making practical computations of the capacity possible. While additivity is
widely believed to be true, there is no proof. Here we show that additivity is
false, by constructing a random counter-example. Our results show that the most
basic question of classical capacity of a quantum channel remains open, with
further work needed to determine in which other situations entanglement can
boost capacity.


title: Symmetric homogeneous diophantine equations of odd degree

abstract:
  We find a parametric solution of an arbitrary symmetric homogeneous
diophantine equation of 5th degree in 6 variables using two primitive
solutions. We then generalize this approach to symmetric forms of any odd
degree by proving the following results.
  (1) Every symmetric form of odd degree $n\ge 5$ in $6 \cdot 2^{n-5}$
variables has a rational parametric solution depending on $2n-8$ parameters.
(2) Let $F(x_1, ..., x_N)$ be a symmetric form of odd degree $n\ge 5$ in $N=6
\cdot 2^{n-4}$ variables, and let $q$ be any rational number. Then the equation
$F(x_i)=q$ has a rational parametric solution depending on $2n-6$ parameters.
  The latter result can be viewed as a solution of a problem of Waring type for
this class of forms.


title:
Tuning flux-pinning in epitaxial NdBa2Cu3O7-x films via engineered,
  hybrid nanoscale defect structures

abstract:
  Epitaxial NdBa2Cu3O7-x films with a hybrid nanoscale defect structure
comprised of BaZrO3 nanodot arrays aligned along the c-axis in one half of the
film thickness and aligned perpendicular to the c-axis in the other half
thickness of the film were fabricated. Transmission electron microscopy images
confirm the orientation of the nanoscale defect structures. The angular
dependence of critical current density, Jc, at 77 K, 1 T, shows significantly
reduced angular variation of Jc. This study nicely demonstrates how pinning
characteristics can be tuned by tuning the nanoscale defect structures within
the films.


title: Van-der-Waals potentials of paramagnetic atoms

abstract:
  We study single- and two-atom van der Waals interactions of ground-state
atoms which are both polarizable and paramagnetizable in the presence of
magneto-electric bodies within the framework of macroscopic quantum
electrodynamics. Starting from an interaction Hamiltonian that includes
particle spins, we use leading-order perturbation theory for the van der Waals
potentials expressed in terms of the polarizability and magnetizability of the
atom(s). To allow for atoms embedded in media, we also include local-field
corrections via the real-cavity model. The general theory is applied to the
potential of a single atom near a half space and that of two atoms embedded in
a bulk medium or placed near a sphere, respectively.


title: Gromov-Witten/Donaldson-Thomas correspondence for toric 3-folds

abstract:
  We prove the equivariant Gromov-Witten theory of a nonsingular toric 3-fold X
with primary insertions is equivalent to the equivariant Donaldson-Thomas
theory of X. As a corollary, the topological vertex calculations by Agangic,
Klemm, Marino, and Vafa of the Gromov-Witten theory of local Calabi-Yau toric
3-folds are proven to be correct in the full 3-leg setting.


title: Radio Properties of Low Redshift Broad Line Active Galactic Nuclei

abstract:
  The question as to whether the distribution of radio-loudness in active
galactic nuclei (AGN) is actually bimodal has been discussed extensively in the
literature. Futhermore, there have been claims that radio-loudness depends on
black hole mass and Eddington ratio. We investigate these claims using the low
redshift broad line AGN sample of Greene & Ho (2007), which consists of 8434
objects at z < 0.35 from the Sloan Digital Sky Survey Fourth Data Release (SDSS
DR4). We obtained radio fluxes from the Very Large Array Faint Images of the
Radio Sky at Twenty-Centimeters (FIRST) survey for the SDSS AGN. Out of the
8434 SDSS AGN, 821 have corresponding observed radio fluxes in the FIRST
survey. We calculated the radio-loudness parameter (R) for all objects above
the FIRST detection limit (1 mJy), and an upper limit to R for the undetected
objects. Using these data, the question of radio bimodality is investigated for
different subsets of the total sample. We find no clear demarcation between the
radio-loud (RL, R > 10) and radio-quiet (RQ, R < 10) objects, but instead fill
in a more radio-intermediate population in a continuous fashion for all
subsamples. We find that 4.7% of the AGN in the flux-limited subsample are RL
based on core radio emission alone. We calculate the radio-loud fraction (RLF)
as both a function of black hole mass and Eddington ratio. The RLF decreases
(from 13% to 2%) as Eddington ratio increases over 2.5 order of magnitude. The
RLF is nearly constant (~5%) over 4 decades in black hole mass, except for an
increase at masses greater than 10^8 solar masses. We find for the FIRST
detected subsample that 367 of the RL AGN have black hole masses less than 10^8
solar masses, a large enough number to indicate that RL AGN are not a product
of only the most massive black holes in the local universe.


title: Multi-market minority game: breaking the symmetry of choice

abstract:
  Generalization of the minority game to more than one market is considered. At
each time step every agent chooses one of its strategies and acts on the market
related to this strategy. If the payoff function allows for strong fluctuation
of utility then market occupancies become inhomogeneous with preference given
to this market where the fluctuation occured first. There exists a critical
size of agent population above which agents on bigger market behave
collectively. In this regime there always exists a history of decisions for
which all agents on a bigger market react identically.

categories: q-fin.TR cond-mat.dis-nn hep-lat nlin.AO physics.soc-ph


title: Counterfactual Quantum Cryptography

abstract:
  Quantum cryptography allows one to distribute a secret key between two remote
parties using the fundamental principles of quantum mechanics. The well-known
established paradigm for the quantum key distribution relies on the actual
transmission of signal particle through a quantum channel. This paper shows
that the task of a secret key distribution can be accomplished even though a
particle carrying secret information is not in fact transmitted through the
quantum channel. The proposed protocols can be implemented with current
technologies and provide practical security advantages by eliminating the
possibility that an eavesdropper can directly access the entire quantum system
of each signal particle.


title:
Heavy quark pair production in gluon fusion at next-to-next-to-leading
  ${\cal O}(\alpha_s^4)$ order: One-loop squared contributions

abstract:
  We calculate the next-to-next-to-leading order ${\cal O}(\alpha_s^4)$
one-loop squared corrections to the production of heavy-quark pairs in the
gluon-gluon fusion process. Together with the previously derived results on the
$q \bar{q}$ production channel the results of this paper complete the
calculation of the one-loop squared contributions of the
next-to-next-to-leading order ${\cal O}(\alpha_s^4)$ radiative QCD corrections
to the hadroproduction of heavy flavors. Our results, with the full mass
dependence retained, are presented in a closed and very compact form, in
dimensional regularization.


title: Surveying Pseudomoduli: the Good, the Bad and the Incalculable

abstract:
  We classify possible types of pseudomoduli which arise when supersymmetry is
dynamically broken in infrared-free low-energy theories. We show that, even if
the pseudomoduli potential is generated only at higher loops, there is a regime
where the potential can be simply determined from a combination of one-loop
running data. In this regime, we compute whether the potential for the various
types of pseudomoduli is safe, has a dangerous runaway to the UV cutoff of the
low-energy theory, or is incalculable. Our results are applicable to building
new models of supersymmetry breaking. We apply the results to survey large
classes of models.


title:
On the self-consistent physical parameters of LMC intermediate-age
  clusters

abstract:
  The LMC clusters are unique templates of simple stellar population (SSP),
being crucial to calibrate models describing the integral light as well as to
test the stellar evolution theory. With this in mind we analyzed HST/WFPC2 (V,
B--V) colour-magnitude diagrams (CMDs) of 15 populous LMC clusters with ages
between ~0.3 Gyr and ~4 Gyr using different stellar evolutionary models
(Padova, PEL or Pisa, BaSTI or Teramo). Following the approach described by
Kerber, Santiago & Brocato (2007), we determined accurate and self-consistent
physical parameters (age, metallicity, distance modulus and reddening) for each
cluster by comparing the observed CMDs with synthetic ones. We found
significant trends in the physical parameters due to the choice of stellar
evolutionary model and treatment of convective core overshooting. In general,
models that incorporate overshooting presented more reliable results than those
that do not. Comparisons with the results found in the literature demonstrated
that our derived metallicities are in good agreement with the ones from the
spectroscopy of red giants. We also confirmed that, independent of the adopted
stellar evolutionary library, the recovered 3D distribution for these clusters
is consistent with a thick disk roughly aligned with the LMC disk as defined by
field stars. Finally, we also provide new estimates of distance modulus to the
LMC center, that are marginally consistent with the canonical value of 18.50.


title: Inverse hyperbolic problems and optical black holes

abstract:
  In this paper we give a more geometrical formulation of the main theorem in
[E1] on the inverse problem for the second order hyperbolic equation of general
form with coefficients independent of the time variable. We apply this theorem
to the inverse problem for the equation of the propagation of light in a moving
medium (the Gordon equation). Then we study the existence of black and white
holes for the general hyperbolic and for the Gordon equation and we discuss the
impact of this phenomenon on the inverse problems.


title: Sur la conjecture de Zagier pour n=4

abstract:
  We express a general 4-hyperlogarithm as a linear combination of
4-hyperlogarithms in two variables. We reduce the Zagier's conjecture for $n=4$
to a combinatorial statement. We give a short survey of the strategy of
Goncharov and Zagier for reducing the Zagier's conjecture for general $n$ to
combinatorial relations between hyperlogarithms. Such a survey is missing in
the literature.


title: Critical interfaces in the random-bond Potts model

abstract:
  We study geometrical properties of interfaces in the random-temperature
q-states Potts model as an example of a conformal field theory weakly perturbed
by quenched disorder. Using conformal perturbation theory in q-2 we compute the
fractal dimension of Fortuin Kasteleyn domain walls. We also compute it
numerically both via the Wolff cluster algorithm for q=3 and via
transfer-matrix evaluations. We obtain numerical results for the fractal
dimension of spin cluster interfaces for q=3. These are found numerically
consistent with the duality kappa(spin) * kappa(FK)= 16 as expressed in
putative SLE parameters.


title:
Neutrino scattering with nuclei - Theory of low energy nuclear effects
  and its applications

abstract:
  Current long baseline experiments aim at measuring neutrino oscillation
parameters with a high precision. A critical quantity is the neutrino energy
which can not be measured directly but has to be reconstructed from the
observed hadrons. A good knowledge of neutrino-nucleus interactions is thus
necessary to minimize the systematic uncertainties in neutrino fluxes,
backgrounds and detector responses. In particular final-state interactions
inside the target nucleus modify considerably the particle yields through
rescattering, charge-exchange and absorption. Nuclear effects can be described
with our coupled channel GiBUU transport model where the neutrino first
interacts with a bound nucleon producing secondary particles which are then
transported out of the nucleus. In this contribution, we give some examples for
the application of our model focusing in particular on the MiniBooNE and K2K
experiments.


title:
Photometric variability of the T Tauri star TW Hya on time scales of
  hours to years

abstract:
  MOST (Microvariability & Oscillations of STars) and ASAS (All Sky Automated
Survey) observations have been used to characterize photometric variability of
TW Hya on time scales from a fraction of a day to 7.5 weeks and from a few days
to 8 years, respectively. The two data sets have very different uncertainties
and temporal coverage properties and cannot be directly combined, nevertheless,
they suggests a global variability spectrum with "flicker noise" properties,
i.e. with amplitudes a ~ 1/sqrt(f), over >4 decades in frequency, in the range
f = 0.0003 to 10 cycles per day (c/d). A 3.7 d period is clearly present in the
continuous 11 day, 0.07 d time resolution, observations by MOST in 2007.
Brightness extrema coincide with zero-velocity crossings in periodic (3.56 d)
radial velocity variability detected in contemporaneous spectroscopic
observations of Setiawan et al. (2008) and interpreted as caused by a planet.
The 3.56/3.7 d periodicity was entirely absent in the second, four times longer
MOST run in 2008, casting doubt on the planetary explanation. Instead, a
spectrum of unstable single periods within the range of 2 - 9 days was
observed; the tendency of the periods to progressively shorten was well traced
using the wavelet analysis. The evolving periodicities and the overall
flicker-noise characteristics of the TW Hya variability suggest a combination
of several mechanisms, with the dominant ones probably related to the accretion
processes from the disk around the star.


title:
Replica theory for fluctuations of the activation barriers in glassy
  systems

abstract:
  We consider the problem of slow activation dynamics in glassy systems
undergoing a random first order phase transition. Using an effective potential
approach to supercooled liquids, we determine the spectrum of activation
barriers for entropic droplets. We demonstrate that fluctuations of the
configurational entropy and of the liquid glass surface tension are crucial to
achieve an understanding of the barrier fluctuations in glassy systems and thus
are ultimatively responsible for the broad spectrum of excitations and
heterogeneous dynamics in glasses. In particular we derive a relation between
the length scale for dynamic heterogeneity and the related barrier
fluctuations. Diluted entropic droplets are shown to have a Gaussian
distribution of barriers, strongly suggesting that non-Gaussian behavior
results from droplet-droplet interactions.


title:
Abrikosov flux-lines in two-band superconductors with mixed
  dimensionality

abstract:
  We study vortex structure in a two-band superconductor, in which one band is
ballistic and quasi-two-dimensional (2D), and the other is diffusive and
three-dimensional (3D). A circular cell approximation of the vortex lattice
within the quasiclassical theory of superconductivity is applied to a recently
developed model appropriate for such a two-band system [Tanaka et al 2006 Phys.
Rev. B 73, 220501(R); Tanaka et al 2007 Phys. Rev. B 75, 214512]. We assume
that superconductivity in the 3D diffusive band is "weak", i.e., mostly
induced, as is the case in MgB$_2$. Hybridization with the "weak" 3D diffusive
band has significant and intriguing influence on the electronic structure of
the "strong" 2D ballistic band. In particular, the Coulomb repulsion and the
diffusivity in the "weak" band enhance suppression of the order parameter and
enlargement of the vortex core by magnetic field in the "strong" band,
resulting in reduced critical temperature and field. Moreover, increased
diffusivity in the "weak" band can result in an upward curvature of the upper
critical field near the transition temperature. A particularly interesting
feature found in our model is the appearance of additional bound states at the
gap edge in the "strong" ballistic band, which are absent in the single-band
case. Furthermore, coupling with the "weak" diffusive band leads to reduced
band gaps and van Hove singularities of energy bands of the vortex lattice in
the "strong" ballistic band. We find these intriguing features for parameter
values appropriate for MgB$_2$.


title:
Cryptic photosynthesis, Extrasolar planetary oxygen without a surface
  biological signature

abstract:
  On the Earth, photosynthetic organisms are responsible for the production of
virtually all of the oxygen in the atmosphere. On the land, vegetation reflects
in the visible, leading to a red edge that developed about 450 Myr ago and has
been proposed as a biosignature for life on extrasolar planets. However, in
many regions of the Earth, and particularly where surface conditions are
extreme, for example in hot and cold deserts, photosynthetic organisms can be
driven into and under substrates where light is still sufficient for
photosynthesis. These communities exhibit no detectable surface spectral
signature to indicate life. The same is true of the assemblages of
photosynthetic organisms at more than a few metres depth in water bodies. These
communities are widespread and dominate local photosynthetic productivity. We
review known cryptic photosynthetic communities and their productivity. We link
geomicrobiology with observational astronomy by calculating the disk-averaged
spectra of cryptic habitats and identifying detectable features on an exoplanet
dominated by such a biota. The hypothetical cryptic photosynthesis worlds
discussed here are Earth-analogs that show detectable atmospheric biomarkers
like our own planet, but do not exhibit a discernable biological surface
feature in the disc-averaged spectrum.


title: High-fidelity entanglement swapping with fully independent sources

abstract:
  Entanglement swapping allows to establish entanglement between independent
particles that never interacted nor share any common past. This feature makes
it an integral constituent of quantum repeaters. Here, we demonstrate
entanglement swapping with time-synchronized independent sources with a
fidelity high enough to violate a Clauser-Horne-Shimony-Holt inequality by more
than four standard deviations. The fact that both entangled pairs are created
by fully independent, only electronically connected sources ensures that this
technique is suitable for future long-distance quantum communication
experiments as well as for novel tests on the foundations of quantum physics.


title:
New X-ray observations of the old nova CP Puppis and of the more recent
  nova V351 Pup

abstract:
  We present X-ray observations of the field containing Nova Puppis 1942 (CP
Pup) and Nova Puppis 1991 (V351 Pup), done with ASCA in 1998, and with
XMM-Newton in 2005. The X-ray and UV luminosity of CP Pup seem to have remained
approximately constant since the last X-ray observations of the 1980'ies, while
the optical luminosity has decreased. The X-ray properties of this nova are
explained by a high mass white dwarf accreting at low rate, in agreement with
the nova theory given the large amplitude and other characteristics of the 1942
outburst.
  Assuming a distance of 1600 pc, the X-ray luminosity of CP Pup is L=2.2 x
10(33) erg/s in the 0.15-10 keV range covered with EPIC, compatible with a
magnetic system. The RGS grating spectrum shows a few prominent emission lines,
and it is fitted with a cooling flow with mass accretion rate mdot <= 1.6 x
10(-10) msol/year. We detected also the O VII complex at 21.6-21.8 A that does
not arise in the cooling flow. Most likely this feature originates in a wind or
in the nova shell. The RGS and EPIC spectra are fitted only with thermal models
with a very high shock temperature, T>60 keV, indicating a white dwarf with
M>1.1 M(sun). The X-ray flux is modulated with the spectroscopic period of 1.47
hours detected in the optical. Since CP Pup is not an eclipsing system, this is
better understood if magnetic accretion occurs: we discuss this possibility and
its implications in detail. V351 Pup (N Pup 1991) was detected with XMM-Newton,
but not with ASCA. It is a faint, non-super-soft X-ray source with luminosity
L(x) =~ 3 x 10(31) erg/s, a factor of 50 less than measured with ROSAT in 1993.


title: Spiky density of states in large complex Al-Mn phases

abstract:
  First-principle electronic structure calculations have been performed in
crystalline complex phases mu-Al4Mn and lambda-Al4Mn using the TB-LMTO method.
These atomic structures, related to quasicrystalline structures, contain about
560 atoms in a large hexagonal unit cell. One of the main characteristic of
their density of states is the presence of fine peaks the so-called "spiky
structure". From multiple-scattering calculations in real space, we show that
these fine peaks are not artifacts in ab-initio calculations, since they result
from a specific localization of electrons by atomic clusters of different
length scales.


title: Regularities of the distribution of abstract van der Corput sequences

abstract:
  Similarly to $\beta$-adic van der Corput sequences, abstract van der Corput
sequences can be defined for abstract numeration systems. Under some
assumptions, these sequences are low discrepancy sequences. The discrepancy
function is computed explicitely, and a characterization of bounded remainder
sets of the form $[0,y)$ is provided.


title:
Direct-space investigation of the ultraslow ballistic dynamics of a soft
  glass

abstract:
  We use light microscopy to investigate the aging dynamics of a glass made of
closely packed soft spheres, following a rapid transition from a fluid to a
solid-like state. By measuring time-resolved, coarse-grained displacements
fields, we identify two classes of dynamical events, corresponding to
reversible and irreversible rearrangements, respectively. The reversible events
are due to the small, experimentally unavoidable fluctuations of the
temperature imposed to the sample, leading to transient thermal expansions and
contractions that cause shear deformations. The irreversible events are plastic
rearrangements, induced by the repeated shear cycles. We show that the
displacement due to the irreversible rearrangements grows linearly with time,
both on average and at a local level. The velocity associated with this
ballistic motion decreases exponentially with sample age, accounting for the
observed slowing down of the dynamics. The displacement field due to the
irreversible rearrangements has a vortex-like structure and is spatially
correlated over surprisingly long distances.


title:
Copolymer-induced stabilizing effect of highly swollen hexagonal
  mesophases

abstract:
  We show quantitatively that tiny amounts of copolymer that decorate a
oil/water interfaces can greatly enhance the stability of swollen surfactant
hexagonal phases, comprising oil tubes regularly arranged in a water matrix.
Such soft composite materials, whose both radius of the tubes and water channel
between the tubes can be controlled independently over large ranges, offer a
potential interest for the synthesis of mesoporous materials.


title: Pinning down the Invisible Sneutrino

abstract:
  For points in SUSY parameter space where the sneutrino is lighter than the
lightest chargino and next-to-lightest neutralino, its direct mass
determination from sneutrino pair production process at e+e- collider is
impossible since it decays invisibly. In such a scenario the sneutrino can be
discovered and its mass determined from measurements of two-body decays of
charginos produced in pairs at the ILC. Using the event generator WHIZARD we
study the prospects of measuring sneutrino properties in a realistic ILC
environment. In our analysis we include beamstrahlung, initial state radiation,
a complete account of reducible backgrounds from SM and SUSY processes, and a
complete matrix-element calculation of the SUSY signal which encompasses all
irreducible background and interference contributions. We also simulate photon
induced background processes using exact matrix elements. Radiation effects and
the cuts to reduce background strongly modify the edges of the lepton energy
spectra from which the sneutrino and chargino mass are determined. We discuss
possible approaches to measure the sneutrino mass with optimal precision.


title: Spin structure functions of 3He at finite Q^2

abstract:
  Using recently derived relations between spin-dependent nuclear and nucleon
g_1 and g_2 structure functions at finite Q^2, we study nuclear effects in 3He
in the nucleon resonance and deep inelastic regions. Comparing the finite-Q^2
results with the standard convolution formulas obtained in the large-Q^2 limit,
we find significant broadening of the effective nucleon momentum distribution
functions, leading to additional suppression of the nuclear g_1 and g_2
structure functions around the resonance peaks.


title: Colliders and Brane Vector Phenomenology

abstract:
  Brane world oscillations manifest themselves as massive vector gauge fields.
Their coupling to the Standard Model is deduced using the method of nonlinear
realizations of the spontaneously broken higher dimensional space-time
symmetries. Brane vectors are stable and weakly interacting, and therefore
escape particle detectors unnoticed. LEP and Tevatron data on the production of
a single photon in conjunction with missing energy are used to delineate
experimentally excluded regions of brane vector parameter space. The additional
region of parameter space accessible to the LHC as well as a future lepton
linear collider is also determined by means of this process.


title: A Criticism of the article "An experimental test of non-local realism"

abstract:
  I make some critical comments on the article "An experimental test of
non-local realism", by S. Groblacher, T. Paterek, R. Kaltenbaek, C. Brukner, M.
Zukowski, M. Aspelmeyer, & A. Zeilinger, Nature 446, p. 871-875 (2007). This
article makes incorrect claims concerning Bell's theorem. Moreover, I point to
the fact that a hypothesis referred to as "realism" in the article (Groblacher
et al.) is not used in the deduction of Leggett's inequality.


title: Mean position of a particle submitted to a potential barrier

abstract:
  A one-dimensional Klein-Gordon problem, which is a physical model for a
quantum particle submitted to a potential barrier, is studied numerically :
using a variational formulation and a Newmark numerical method, we compute the
mean position and standard deviation of the particle as well as their time
evolution.


title: Where lies the peak of the brown dwarf binary separation distribution ?

abstract:
  Searches for companions of brown dwarfs by direct imaging probe mainly
orbital separations > 3-10 AU. On the other hand, previous radial velocity
surveys of brown dwarfs are mainly sensitive to separations smaller than 0.6
AU. It has been speculated if the peak of the separation distribution of brown
dwarf binaries lies right in the unprobed range. Very recent work for the first
time extends high-precision radial velocity surveys of brown dwarfs out to 3 AU
(Joergens 2008, A&A). Based on more than six years UVES/VLT spectroscopy the
binary frequency of brown dwarfs and (very) low-mass stars (M4.25-M8) in ChaI
was determined: it is 18% for the whole sample and 10% for the subsample of ten
brown dwarfs and VLMS (M < 0.1 Msun). Two spectroscopic binaries were
confirmed, these are the brown dwarf candidate ChaHa8, and the low-mass star
CHXR74. Since their orbital separations appear to be 1 AU or greater, the
binary frequency at < 1 AU might be less than 10%. Now for the first time
companion searches of (young) brown dwarfs cover the whole orbital separation
range and the following observational constraints for models of brown dwarf
formation can be derived: (i) the frequency of brown dwarf and very low-mass
stellar binaries at < 3 AU is not significantly exceeding that at > 3 AU; i.e.
direct imaging surveys do not miss a significant fraction of brown dwarf
binaries; (ii) the overall binary frequency of brown dwarfs and very low-mass
stars is 10-30 %; (iii) the decline of the separation distribution of brown
dwarfs towards smaller separations seem to occur between 1 and 3 AU; (iv) the
observed continuous decrease of the binary frequency from the stellar to the
substellar regime is confirmed at < 3 AU providing further evidence for a
continuous formation mechanism from low-mass stars to brown dwarfs.


title:
A global autocorrelation study after the first Auger data: impact on the
  number density of UHECR sources

abstract:
  We perform an autocorrelation study of the Auger data with the aim to
constrain the number density n_s of ultrahigh energy cosmic ray (UHECR)
sources, estimating at the same time the effect on $n_s$ of the systematic
energy scale uncertainty and of the distribution of UHECR. The use of global
analysis has the advantage that no biases are introduced, either in n_s or in
the related error bar, by the a priori choice of a single angular scale. The
case of continuous, uniformly distributed sources is nominally disfavored at
99% C.L. and the fit improves if the sources follow the large-scale structure
of matter in the universe. The best fit values obtained for the number density
of proton sources are within a factor ~2 around n_s ~ 10^{-4}/Mpc^3 and depend
mainly on the Auger energy calibration scale, with lower densities being
preferred if the current scale is correct. The data show no significant
small-scale clustering on scales smaller than a few degrees. This might be
interpreted as a signature of magnetic smearing of comparable size, comparable
with the indication of a ~3 degrees magnetic deflection coming from
cross-correlation results. The effects on the above results of some
approximations done is also discussed.


title:
There is no explosion risk associated with superfluid Helium in the LHC
  cooling system

abstract:
  We evaluate speculation about the possibility of a dangerous release of
energy within the liquid Helium of the Large Hadron Collider (LHC) cryogenic
system due to the occurrence of a "Bose-Nova". Bose-Novae are radial bursts of
rapidly moving atoms which can occur when a Bose-Einstein Condensate (BEC)
undergoes a collapse due the interatomic potential being deliberately made
attractive using a magnetic field close to the Feshbach resonance. Liquid 4He
has a monatomic structure with s-wave electrons, zero nuclear spin, no
hyperfine splitting, and as a consequence no Feshbach resonance which would
allow one to change its normally repulsive interactions to be attractive.
Because of this, a Bose-Nova style collapse of 4He is impossible. Additional
speculations concerning cold fusion during these events are easily dismissed
using the usual arguments about the Coulomb barrier at low temperatures, and
are not needed to explain the Bose-Einstein condensate Bose-Nova phenomenon. We
conclude that that there is no physics whatsoever which suggests that Helium
could undergo any kind of unforeseen catastrophic explosion.

categories: physics.pop-ph cond-mat.other hep-ex hep-ph physics.atom-ph physics.ins-det


title: Dissipation and Heating in Supersonic Hydrodynamic and MHD Turbulence

abstract:
  We study energy dissipation and heating by supersonic MHD turbulence in
molecular clouds using Athena, a new higher-order Godunov code. We analyze the
dependence of the saturation amplitude, energy dissipation characteristics,
power spectra, sonic scaling, and indicators of intermittency in the turbulence
on factors such as the magnetic field strength, driving scale, energy injection
rate, and numerical resolution. While convergence in the energies is reached at
moderate resolutions, we find that the power spectra require much higher
resolutions that are difficult to obtain. In a 1024^3 hydro run, we find a
power law relationship between the velocity dispersion and the spatial scale on
which it is measured, while for an MHD run at the same resolution we find no
such power law. The time-variability and temperature intermittency in the
turbulence both show a dependence on the driving scale, indicating that
numerically driving turbulence by an arbitrary mechanism may not allow a
realistic representation of these properties. We also note similar features in
the power spectrum of the compressive component of velocity for supersonic MHD
turbulence as in the velocity spectrum of an initially-spherical MHD blast
wave, implying that the power law form does not rule out shocks, rather than a
turbulent cascade, playing a significant role in the regulation of energy
transfer between spatial scales.


title: The Orion Molecular Cloud 2/3 and NGC 1977 Regions

abstract:
  The Orion Molecular Cloud 2/3 region (hereafter, OMC-2/3) and the reflection
nebula NGC 1977 encompass a section of the Orion A molecular cloud undergoing
vigorous star forming activity. One of the richest assemblages of protostars in
the nearest 500 pc is seen in OMC-2/3, while NGC 1977 contains a cluster of
over 100 young stars. In this review, we present a census of the protostars,
pre-main sequence stars, and young brown dwarfs in these regions. These are
identified through sub-millimeter surveys, far-red to near-infrared imaging and
spectroscopy with ground-based telescopes, mid-infrared photometry from the
Spitzer Space Telescope, and X-ray observations made with the Chandra X-ray
Observatory. We present an overview of the distribution of molecular gas
associated with these regions and the rich complex of shock heated nebulae
created by the young stars interacting with the molecular gas. Finally, we
discuss the relationship of OMC-2/3 and NGC 1977 to the neighboring Orion
Nebula Cluster and the Orion OB1 association.


title: Off-nuclear AGN as a signature of recoiling massive black holes

abstract:
  During the final phases of inspiral, a massive black hole (MBH) binary
experiences a recoil due to the asymmetric emission of gravitational waves. We
use recent results from numerical relativity simulations together with models
of the assembly and growth of MBHs in hierarchical cosmologies, to study the
dynamics, statistics, and observability of recoling MBHs. We find that, at
redshift z<3, kicked non-rotating holes are typically found between 1 and 30
kpc from their galaxy centers, while rapidly rotating ones are typically
between 10 and a few hundred kpc. A recoiling hole that carries an accretion
disk may shine as an "off-nuclear AGN" while it moves away from the center of
its host galaxy. We predict that, depending on the hole spin distribution and
the duration of their active phase, a population of off-nuclear AGN may already
be detectable at low and intermediate redshifts in present deep Hubble Space
Telescope observations. The James Webb Space Telescope may discover tens of
wandering AGN per square degree, most of them moving within their host halos on
unbound trajectories.


title:
Cosmology With Many Light Scalar Fields: Stochastic Inflation and Loop
  Corrections

abstract:
  We explore the consequences of the existence of a very large number of light
scalar degrees of freedom in the early universe. We distinguish between
participator and spectator fields. The former have a small mass, and can
contribute to the inflationary dynamics; the latter are either strictly
massless or have a negligible VEV. In N-flation and generic assisted inflation
scenarios, inflation is a co-operative phenomenon driven by N participator
fields, none of which could drive inflation on their own. We review upper
bounds on N, as a function of the inflationary Hubble scale H. We then consider
stochastic and eternal inflation in models with N participator fields showing
that individual fields may evolve stochastically while the whole ensemble
behaves deterministically, and that a wide range of eternal inflationary
scenarios are possible in this regime. We then compute one-loop quantum
corrections to the inflationary power spectrum. These are largest with N
spectator fields and a single participator field, and the resulting bound on N
is always weaker than those obtained in other ways. We find that loop
corrections to the N-flation power spectrum do not scale with N, and thus place
no upper bound on the number of participator fields. This result also implies
that, at least to leading order, the theory behaves like a composite single
scalar field. In order to perform this calculation, we address a number of
issues associated with loop calculations in the Schwinger-Keldysh "in-in"
formalism.


title:
Renormalization of the S Parameter in Holographic Models of Electroweak
  Symmetry Breaking

abstract:
  We show that the S parameter is not finite in theories of electroweak
symmetry breaking in a slice of anti--de Sitter five-dimensional space, with
the light fermions localized in the ultraviolet. We compute the one-loop
contributions to S from the Higgs sector and show that they are logarithmically
dependent on the cutoff of the theory. We discuss the renormalization of S, as
well as the implications for bounds from electroweak precision measurements on
these models. We argue that, although in principle the choice of
renormalization condition could eliminate the S parameter constraint, a more
consistent condition would still result in a large and positive S. On the other
hand, we show that the dependence on the Higgs mass in S can be entirely
eliminated by the renormalization procedure, making it impossible in these
theories to extract a Higgs mass bound from electroweak precision constraints.


title:
Vertex operators and the geometry of moduli spaces of framed
  torsion-free sheaves

abstract:
  We define complexes of vector bundles on products of moduli spaces of framed
rank r torsion-free sheaves on the complex projective plane. The top
non-vanishing Chern classes of the cohomology of these complexes yield actions
of the r-colored Heisenberg and Clifford algebras on the equivariant cohomology
of the moduli spaces. In this way we obtain a geometric realization of the
boson-fermion correspondence and related vertex operators.


title:
Prospects for CDM sub-halo detection using high angular resolution
  observations

abstract:
  In the CDM scenario, dark matter halos are assembled hierarchically from
smaller subunits. A long-standing problem with this picture is that the number
of sub-halos predicted by CDM simulations is orders of magnitudes higher than
the known number of satellite galaxies in the vicinity of the Milky Way. A
plausible way out of this problem could be that the majority of these sub-halos
somehow have so far evaded detection. If such "dark galaxies" do indeed exist,
gravitational lensing may offer one of the most promising ways to detect them.
Dark matter sub-halos in the 1e6 - 1e10 solar mass range should cause strong
gravitational lensing on (sub)milliarcsecond scales. We study the feasibility
of a strong lensing detection of dark sub-halos by deriving the image
separations expected for density profiles favoured by recent simulations and
comparing these to the angular resolution of both existing and upcoming
observational facilities. We find that there is a reasonable probability to
detect sub-halo lensing effects in high resolution observations at radio
wavelengths, such as produced by the upcoming VSOP-2 satellite, and thereby
test the existence of dark galaxies.


title: Properties of the Youngest Protostars in Perseus, Serpens, and Ophiuchus

abstract:
  We present an unbiased census of deeply embedded protostars in Perseus,
Serpens, and Ophiuchus, assembled by combining large-scale 1.1 mm Bolocam
continuum and Spitzer Legacy surveys. We identify protostellar candidates based
on their mid-infrared properties, correlate their positions with 1.1 mm core
positions, and construct well-sampled SEDs using our extensive wavelength
coverage (lam=1.25-1100 micron). Source classification based on the bolometric
temperature yields a total of 39 Class 0 and 89 Class I sources in the three
cloud sample. We compare to protostellar evolutionary models using the
bolometric temperature-luminosity diagram, finding a population of low
luminosity Class I sources that are inconsistent with constant or monotonically
decreasing mass accretion rates. This result argues strongly for episodic
accretion during the Class I phase, with more than 50% of sources in a
``sub-Shu'' (dM/dt < 1e-6 Msun/yr) accretion state. Average spectra are
compared to protostellar radiative transfer models, which match the observed
spectra fairly well in Stage 0, but predict too much near-IR and too little
mid-IR flux in Stage I. Finally, the relative number of Class 0 and Class I
sources are used to estimate the lifetime of the Class 0 phase; the three cloud
average yields a Class 0 lifetime of 1.7e5 yr, ruling out an extremely rapid
early accretion phase. Correcting photometry for extinction results in a
somewhat shorter lifetime (1.1e5 yr). In Ophiuchus, however, we find very few
Class 0 sources (N(Class0)/N(ClassI)=0.1-0.2), similar to previous studies of
that cloud. The observations suggest a consistent picture of nearly constant
average accretion rate through the entire embedded phase, with accretion
becoming episodic by at least the Class I stage, and possibly earlier.


title: On the variability of HD 170699 - a possible COROT target

abstract:
  We present the analysis of the variability of HD 170699, a COROT star showing
the characteristics of a non evolutionary Delta Scuti star with high rotational
velocity. There is a clear period of 10.45 c/d with 5.29 mmag amplitude in the
y filter. From the data, it can be seen that the star shows multi-periodicity
and it is necessary to add more frequencies to adjust the observations


title:
Will it be possible to measure intrinsic gravitomagnetism with Lunar
  Laser Ranging?

abstract:
  In this note we mainly explore the possibility of measuring the action of the
intrinsic gravitomagnetic field of the rotating Earth on the orbital motion of
the Moon with the Lunar Laser Ranging (LLR) technique. Expected improvements in
it should push the precision in measuring the Earth-Moon range to the mm level;
the present-day Root-Mean-Square (RMS) accuracy in reconstructing the radial
component of the lunar orbit is about 2 cm; its harmonic terms can be
determined at the mm level. The current uncertainty in measuring the lunar
precession rates is about 10^-1 milliarcseconds per year. The Lense-Thirring
secular, i.e. averaged over one orbital period, precessions of the node and the
perigee of the Moon induced by the Earth's spin angular momentum amount to
10^-3 milliarcseconds per year yielding transverse and normal shifts of
10^-1-10^-2 cm yr^-1. In the radial direction there is only a short-period,
i.e. non-averaged over one orbital revolution, oscillation with an amplitude of
10^-5 m. Major limitations come also from some systematic errors induced by
orbital perturbations of classical origin like, e.g., the secular precessions
induced by the Sun and the oblateness of the Moon whose mismodelled parts are
several times larger than the Lense-Thirring signal. The present analysis holds
also for the Lue-Starkman perigee precession due to the multidimensional
braneworld model by Dvali, Gabadadze and Porrati (DGP); indeed, it amounts to
about 5 X 10^-3 milliarcseconds per year.


title: Infall Regions and Scaling Relations of X-ray Selected Groups

abstract:
  We use the Fifth Data Release of the Sloan Digital Sky Survey to study
X-ray-selected galaxy groups and compare their properties to clusters. We
search for infall patterns around the groups and use these to measure group
mass profiles to large radii. In previous work, we analyzed infall patterns for
an X-ray-selected sample of 72 clusters from the ROSAT All-Sky Survey. Here, we
extend this approach to a sample of systems with smaller X-ray fluxes selected
from the 400 Square Degree serendipitous survey of clusters and groups in ROSAT
pointed observations. We identify 16 groups with SDSS DR5 spectroscopy, search
for infall patterns, and compute mass profiles out to 2-6 Mpc from the group
centers with the caustic technique. No other mass estimation methods are
currently available at such large radii for these low-mass groups, because the
virial estimate requires dynamical equilibrium and the gravitational lensing
signal is too weak. Despite the small masses of these groups, most display
recognizable infall patterns. We use caustic and virial mass estimates to
measure the scaling relations between different observables, extending these
relations to smaller fluxes and luminosities than many previous surveys. Close
inspection reveals that three of the groups are subclusters in the outskirts of
larger clusters. A fourth group is apparently undergoing a group-group merger.
These four merging groups represent the most extreme outliers in the scaling
relations. Excluding these groups, we find $L_X\propto\sigma_p^{3.4\pm1.6}$,
consistent with previous determinations for both clusters and groups.
Understanding cluster and group scaling relations is crucial for measuring
cosmological parameters from clusters.


title:
Origin of intermittent accretion-powered X-ray oscillations in neutron
  stars with millisecond spin periods

abstract:
  We have shown previously that many of the properties of persistent
accretion-powered millisecond pulsars can be understood if their X-ray emitting
areas are near their spin axes and move as the accretion rate and structure of
the inner disk vary. Here we show that this "nearly aligned moving spot model"
may also explain the intermittent accretion-powered pulsations that have been
detected in three weakly magnetic accreting neutron stars. We show that
movement of the emitting area from very close to the spin axis to about 10
degrees away can increase the fractional rms amplitude from less than about 0.5
percent, which is usually undetectable with current instruments, to a few
percent, which is easily detectable. The second harmonic of the spin frequency
usually would not be detected, in agreement with observations. The model
produces intermittently detectable oscillations for a range of emitting area
sizes and beaming patterns, stellar masses and radii, and viewing directions.
Intermittent oscillations are more likely in stars that are more compact. In
addition to explaining the sudden appearance of accretion-powered millisecond
oscillations in some neutron stars with millisecond spin periods, the model
explains why accretion-powered millisecond oscillations are relatively rare and
predicts that the persistent accretion-powered millisecond oscillations of
other stars may become undetectable for brief intervals. It suggests why
millisecond oscillations are frequently detected during the X-ray bursts of
some neutron stars but not others and suggests mechanisms that could explain
the occasional temporal association of intermittent accretion-powered
oscillations with thermonuclear X-ray bursts.