title: The expansion field: The value of H_0

abstract:
  Any calibration of the present value of the Hubble constant requires
recession velocities and distances of galaxies. While the conversion of
observed velocities into true recession velocities has only a small effect on
the result, the derivation of unbiased distances which rest on a solid zero
point and cover a useful range of about 4-30 Mpc is crucial. A list of 279 such
galaxy distances within v<2000 km/s is given which are derived from the tip of
the red-giant branch (TRGB), from Cepheids, and from supernovae of type Ia (SNe
Ia). Their random errors are not more than 0.15 mag as shown by
intercomparison. They trace a linear expansion field within narrow margins from
v=250 to at least 2000 km/s. Additional 62 distant SNe Ia confirm the linearity
to at least 20,000 km/s. The dispersion about the Hubble line is dominated by
random peculiar velocities, amounting locally to <100 km/s but increasing
outwards. Due to the linearity of the expansion field the Hubble constant H_0
can be found at any distance >4.5 Mpc. RR Lyr star-calibrated TRGB distances of
78 galaxies above this limit give H_0=63.0+/-1.6 at an effective distance of 6
Mpc. They compensate the effect of peculiar motions by their large number.
Support for this result comes from 28 independently calibrated Cepheids that
give H_0=63.4+/-1.7 at 15 Mpc. This agrees also with the large-scale value of
H_0=61.2+/-0.5 from the distant, Cepheid-calibrated SNe Ia. A mean value of
H_0=62.3+/-1.3 is adopted. Because the value depends on two independent zero
points of the distance scale its systematic error is estimated to be 6%.
Typical errors of H_0 come from the use of a universal, yet unjustified P-L
relation of Cepheids, the neglect of selection bias in magnitude-limited
samples, or they are inherent to the adopted models.


title: Galactic and Extragalactic Distance Scales: The Variable Star Project

abstract:
  This paper summaries the status of a large project to improve distance scales
of various classes of variable stars. This is being carried out by a large
group in Cape Town, Japan, England and the USA. The results are illustrated by
giving the distances of the Large Magellanic Cloud and the Galactic Centre (Ro)
as well as the value of the Hubble Constant, Ho, based on our current results.
The classes of variables considered are; Classical Cepheids, Type II Cepheids,
RR Lyrae stars, O- and C-Miras


title:
The high temperature Ising model on the triangular lattice is a critical
  percolation model

abstract:
  The Ising model at inverse temperature $\beta$ and zero external field can be
obtained via the Fortuin-Kasteleyn (FK) random-cluster model with $q=2$ and
density of open edges $p=1-e^{-\beta}$ by assigning spin +1 or -1 to each
vertex in such a way that (1) all the vertices in the same FK cluster get the
same spin and (2) +1 and -1 have equal probability. We generalize the above
procedure by assigning spin +1 with probability $r$ and -1 with probability
$1-r$, with $r \in [0,1]$, while keeping condition (1). For fixed $\beta$, this
generates a dependent (spin) percolation model with parameter $r$. We show
that, on the triangular lattice and for $\beta<\beta_c$, this model has a
percolation phase transition at $r=1/2$, corresponding to the Ising model. This
sheds some light on the conjecture that the high temperature Ising model on the
triangular lattice is in the percolation universality class and that its
scaling limit can be described in terms of SLE$_6$. We also prove uniqueness of
the infinite +1 cluster for $r>1/2$, sharpness of the percolation phase
transition (by showing exponential decay of the cluster size distribution for
$r<1/2$), and continuity of the percolation function for all $r \in [0,1]$.


title:
The ALHAMBRA Project: A large area multi medium-band optical and NIR
  photometric survey

abstract:
  (ABRIDGED) We describe the first results of the ALHAMBRA survey which
provides cosmic tomography of the evolution of the contents of the Universe
over most of Cosmic history. Our approach employs 20 contiguous, equal-width,
medium-band filters covering from 3500 to 9700 A, plus the JHKs bands, to
observe an area of 4 sqdeg on the sky. The optical photometric system has been
designed to maximize the number of objects with accurate classification by SED
and redshift, and to be sensitive to relatively faint emission lines. The
observations are being carried out with the Calar Alto 3.5m telescope using the
cameras LAICA and O-2000. The first data confirm that we are reaching the
expected magnitude limits of AB<~25 mag in the optical filters from the blue to
8300 A, and from AB=24.7 to 23.4 for the redder ones. The limit in the NIR is
(Vega) K_s~20, H~21, J~22. We expect to obtain accurate redshift values, Delta
z/(1+z) <~ 0.03 for about 5x10^5 galaxies with I<~25 (60% complete), and
z_med=0.74. This accuracy, together with the homogeneity of the selection
function, will allow for the study of the redshift evolution of the large scale
structure, the galaxy population and its evolution with redshift, the
identification of clusters of galaxies, and many other studies, without the
need for any further follow-up. It will also provide targets for detailed
studies with 10m-class telescopes. Given its area, spectral coverage and its
depth, apart from those main goals, the ALHAMBRA-Survey will also produce
valuable data for galactic studies.


title: Thermal Emission from Warm Dust in the Most Distant Quasars

abstract:
  We report new continuum observations of fourteen z~6 quasars at 250 GHz and
fourteen quasars at 1.4 GHz. We summarize all recent millimeter and radio
observations of the sample of the thirty-three quasars known with
5.71<=z<=6.43, and present a study of the rest frame far-infrared (FIR)
properties of this sample. These quasars were observed with the Max Plank
Millimeter Bolometer Array (MAMBO) at 250 GHz with mJy sensitivity, and 30% of
them were detected. We also recover the average 250 GHz flux density of the
MAMBO undetected sources at 4 sigma, by stacking the on-source measurements.
The derived mean radio-to-UV spectral energy distributions (SEDs) of the full
sample and the 250 GHz non-detections show no significant difference from that
of lower-redshift optical quasars. Obvious FIR excesses are seen in the
individual SEDs of the strong 250 GHz detections, with FIR-to-radio emission
ratios consistent with that of typical star forming galaxies. Most 250
GHz-detected sources follow the L_{FIR}--L_{bol} relationship derived from a
sample of local IR luminous quasars (L_{IR}>10^{12}L_{\odot}), while the
average L_{FIR}/L_{bol} ratio of the non-detections is consistent with that of
the optically-selected PG quasars. The MAMBO detections also tend to have
weaker Ly\alpha emission than the non-detected sources. We discuss possible FIR
dust heating sources, and critically assess the possibility of active star
formation in the host galaxies of the z~6 quasars. The average star formation
rate of the MAMBO non-detections is likely to be less than a few hundred
M_{\odot} yr^{-1}, but in the strong detections, the host galaxy star formation
is probably at a rate of \gtrsim10^{3} M_{\odot} yr^{-1}, which dominates the
FIR dust heating.


title:
A Random Search Framework for Convergence Analysis of Distributed
  Beamforming with Feedback

abstract:
  The focus of this work is on the analysis of transmit beamforming schemes
with a low-rate feedback link in wireless sensor/relay networks, where nodes in
the network need to implement beamforming in a distributed manner.
Specifically, the problem of distributed phase alignment is considered, where
neither the transmitters nor the receiver has perfect channel state
information, but there is a low-rate feedback link from the receiver to the
transmitters. In this setting, a framework is proposed for systematically
analyzing the performance of distributed beamforming schemes. To illustrate the
advantage of this framework, a simple adaptive distributed beamforming scheme
that was recently proposed by Mudambai et al. is studied. Two important
properties for the received signal magnitude function are derived. Using these
properties and the systematic framework, it is shown that the adaptive
distributed beamforming scheme converges both in probability and in mean.
Furthermore, it is established that the time required for the adaptive scheme
to converge in mean scales linearly with respect to the number of sensor/relay
nodes.


title:
Rates of contraction of posterior distributions based on Gaussian
  process priors

abstract:
  We derive rates of contraction of posterior distributions on nonparametric or
semiparametric models based on Gaussian processes. The rate of contraction is
shown to depend on the position of the true parameter relative to the
reproducing kernel Hilbert space of the Gaussian process and the small ball
probabilities of the Gaussian process. We determine these quantities for a
range of examples of Gaussian priors and in several statistical settings. For
instance, we consider the rate of contraction of the posterior distribution
based on sampling from a smooth density model when the prior models the log
density as a (fractionally integrated) Brownian motion. We also consider
regression with Gaussian errors and smooth classification under a logistic or
probit link function combined with various priors.


title:
Study of beta-delayed 3-body and 5-body breakup channels observed in the
  decay of ^11Li

abstract:
  The beta-delayed charged particle emission from ^11Li has been studied with
emphasis on the three-body n+alpha+^6He and five-body 2alpha+3n channels from
the 10.59 and 18.15 MeV states in ^11Be. Monte Carlo simulations using an
R-matrix formalism lead to the conclusion that the ^AHe resonance states play a
significant role in the break-up of these states. The results exclude an
earlier assumption of a phase-space description of the break-up process of the
18.15 MeV state. Evidence for extra sequential decay paths is found for both
states.


title:
Distributional Schwarzschild Geometry from nonsmooth regularization via
  Horizon. Disributional Rindler spacetime with disributional Levi-Civit\`a
  connection induced vacuum dominance.Unruh effect revisited

abstract:
  In this paper we leave the neighborhood of the singularity at the origin and
turn to the singularity at the horizon. Using nonlinear superdistributional
geometry and supergeneralized functions it seems possible to show that the
horizon singularity is not only a coordinate singularity without leaving
Schwarzschild coordinates. However the Tolman formula for the total energy $E$
of a static and asymptotically flat spacetime,gives $E=mc^2$, as it should be.
New class Colombeau solutions to Einstein field equations is obtained.New class
Colombeau solutions to Einstein field equations is obtained. The vacuum energy
density of free scalar quantum field ${\Phi}$ with a distributional background
spacetime also is considered.It has been widely believed that, except in very
extreme situations, the influence of acceleration on quantum fields should
amount to just small, sub-dominant contributions. Here we argue that this
belief is wrong by showing that in a Rindler distributional background
spacetime with distributional Levi-Civit\`a connection the vacuum energy of
free quantum fields is forced, by the very same background distributional
space-time such a Rindler distributional background space-time, to become
dominant over any classical energy density component.This semiclassical gravity
effect finds its roots in the singular behavior of quantum fields on a Rindler
distributional space-times with distributional Levi-Civit\`a connection. In
particular we obtain that the vacuum fluctuations $<{\Phi}^2({\delta})>$ have a
singular behavior at a Rindler horizon $\delta = 0$.Therefore sufficiently
strongly accelerated observer burns up near the Rindler horizon. Thus
Polchinski account does not violate of the Einstein equivalence principle.


title:
Observation of Upsilon(2S) -> eta Upsilon(1S) and search for related
  transitions

abstract:
  We report the first observation of the transition Upsilon(2S) > eta
Upsilon(1S), with branching fraction B=(2.1+0.7-0.6(stat.)+-0.3(syst.)) x
10^{-4} and statistical significance 5.3 sigma. Data were acquired with the
CLEO detector at the CESR e+ e- symmetric collider. This is the first process
observed involving a b-quark spin flip. Upper limits at 90% confidence level
for related processes, in units of 10^{-4}, are B[Upsilon(2S) -> pi0
Upsilon(1S)] < 1.8, B[Upsilon(3S) -> eta Upsilon(1S)] < 1.8, B[Upsilon(3S) ->
pi0 Upsilon(1S)] < 0.7, and B[Upsilon(3S) -> pi0 Upsilon(2S)] < 5.1.


title: The Gottfried sum rule in an unquenched quark model

abstract:
  We present an unquenched quark model for baryons in which the effects of
quark-antiquark pairs (light flavors, u, d and s) are taken into account in an
explicit form. The method is illustrated with an application to the flavor
asymmetry of the nucleon sea.


title:
Signatures of sterile neutrino mixing in high-energy cosmic neutrino
  flux

abstract:
  Even after the negative result by the MiniBooNE experiment, we can still have
a (3+1)-scheme with one sterile neutrino whose mixing lies within the allowed
region by MiniBooNE. In this note we discuss the possible effects of such a
scheme on the flavor ratio of high-energy cosmic neutrinos from cosmologically
distant astrophysical sources. It is shown that in principle there is still a
chance to observe deviation from the standard three flavor scenario in the
flavor ratio of the high-energy cosmic neutrinos. It is proposed to see the
energy spectrum to cope with the theoretical uncertainties which were recently
pointed out by Lipari, Lusignoli and Meloni. It is emphasized that the
$\nu_\mu-\nu_\tau$ ratio is relatively insensitive to the theoretical
uncertainties and therefore this ratio is the key ingredient to look for the
signatures of the sterile neutrino scheme. Although the statistics of data from
one source in the next generation of neutrino telescopes are estimated not to
be sufficient to distinguish the three and four family schemes, if we can gain
statistics by, e.g., summing over data from many sources, then it might be
possible to have a signature for the (3+1)-scheme.


title: Imaging method for interface rheological characterization

abstract:
  The present work investigates free damped oscillations of an oil drop in
water after its release from a capillary tube. Both pure heptane drops and
diluted crude oil drops are considered (in the second case the interface is
covered by amphiphilic species, natural components of crude oil). Shadowgraph
images of the drops are taken by means of a high speed camera and the drop
contour is detected by image processing. The axisymmetric drop shape is then
decomposed into spherical harmonics, which constitute the eigenmodes of
oscillations predicted by the Rayleigh-Lamb theory. Time evolution of each mode
is then obtained. The frequency and the damping rate of the principal mode
(n=2) are accurately determined and compared with theoretical values for an
immobile clean drop oscillating around spherical shape. For pure heptane drops,
theoretical value of the frequency agrees well with experiments whereas the
damping rate is significantly underestimated by theory. The experimental
results clearly show that the different modes are coupled. Energy is thus
transfered from mode n=2 to n=3, which probably explains the observed
enhancement of the damping rate. The effect of the interface viscoelastic
behaviour, induced by adsorbed amphiphilic species on the free oscillations was
examined. No significant effect was observed in the experiments conditions
(small amplitude oscillations and moderate aging).


title: Multi Site Coordination using a Multi-Agent System

abstract:
  A new approach of coordination of decisions in a multi site system is
proposed. It is based this approach on a multi-agent concept and on the
principle of distributed network of enterprises. For this purpose, each
enterprise is defined as autonomous and performs simultaneously at the local
and global levels. The basic component of our approach is a so-called Virtual
Enterprise Node (VEN), where the enterprise network is represented as a set of
tiers (like in a product breakdown structure). Within the network, each partner
constitutes a VEN, which is in contact with several customers and suppliers.
Exchanges between the VENs ensure the autonomy of decision, and guarantiee the
consistency of information and material flows. Only two complementary VEN
agents are necessary: one for external interactions, the Negotiator Agent (NA)
and one for the planning of internal decisions, the Planner Agent (PA). If
supply problems occur in the network, two other agents are defined: the Tier
Negotiator Agent (TNA) working at the tier level only and the Supply Chain
Mediator Agent (SCMA) working at the level of the enterprise network. These two
agents are only active when the perturbation occurs. Otherwise, the VENs
process the flow of information alone. With this new approach, managing
enterprise network becomes much more transparent and looks like managing a
simple enterprise in the network. The use of a Multi-Agent System (MAS) allows
physical distribution of the decisional system, and procures a heterarchical
organization structure with a decentralized control that guaranties the
autonomy of each entity and the flexibility of the network.


title: Multi-agents architecture for supply chain management

abstract:
  The purpose of this paper is to propose a new approach for the supply chain
management. This approach is based on the virtual enterprise paradigm and the
used of multi-agent concept. Each entity (like enterprise) is autonomous and
must perform local and global goals in relation with its environment. The base
component of our approach is a Virtual Enterprise Node (VEN). The supply chain
is viewed as a set of tiers (corresponding to the levels of production), in
which each partner of the supply chain (VEN) is in relation with several
customers and suppliers. Each VEN belongs to one tier. The main customer gives
global objectives (quantity, cost and delay) to the supply chain. The Mediator
Agent (MA) is in charge to manage the supply chain in order to respect those
objectives as global level. Those objectives are taking over to Negotiator
Agent at the tier level (NAT). These two agents are only active if a
perturbation occurs; otherwise information flows are only exchange between
VENs. This architecture allows supply chains management which is completely
transparent seen from simple enterprise of the supply chain. The used of
Multi-Agent System (MAS) allows physical distribution of the decisional system.
Moreover, the hierarchical organizational structure with a decentralized
control guaranties, in the same time, the autonomy of each entity and the whole
flexibility.


title: Compound Node-Kayles on Paths

abstract:
  In his celebrated book "On Number and Games" (Academic Press, New-York,
1976), J.H. Conway introduced twelve versions of compound games. We analyze
these twelve versions for the Node-Kayles game on paths. For usual disjunctive
compound, Node-Kayles has been solved for a long time under normal play, while
it is still unsolved under mis\`ere play. We thus focus on the ten remaining
versions, leaving only one of them unsolved.


title:
Capillary and anchoring effects in thin hybrid nematic films and
  connection with bulk behavior

abstract:
  By means of a molecular model, we examine hybrid nematic films with
antagonistic anchoring angles where one of the surfaces is in the strong
anchoring regime. If anchoring at the other surface is weak, and in the absence
of wetting by the isotropic phase, the anchoring transition may interact with
the capillary isotropic-nematic transition in interesting ways. For general
anchoring conditions on this surface we confirm the existence of the step-tilt,
biaxial phase and the associated transition to the linear,
constant-tilt-rotation, configuration. The step-like phase is connected with
the bulk isotropic phase for increasing film thickness so that the latter
transition is to be interpreted as the capillary isotropic-nematic transition.
Finally, we suggest possible global surface phase diagrams.


title:
Porosity Effect on Surface Plasmon Resonance from Metallic Sculptured
  Thin Films

abstract:
  When a sculptured thin film (STF), made of a metal and $\leq50$ nm thick, is
used in lieu of a dense layer of metal in the Kretschmann configuration,
experimental data for an STF comprising parallel tilted nanowires shows that a
surface plasmon resonance (SPR) can still be excited. As the porosity of the
chosen STF increases, experimental data and numerical simulations indicate the
SPR dip with respect to the angle of incidence of the exciting plane wave
widens and eventually disappears, leaving behind a a vestigial peak near the
onset to the total-internal-reflection regime.


title: Codimension one generic homoclinic classes with interior

abstract:
  We study generic diffeomorphisms with a homoclinc class with non empty
interior and in particular those admitting a codimension one dominated
splitting. We prove that if in the finest dominated splitting the extreme
subbundles are one dimensional then the diffeomorphism is partially hyperbolic
and from this we deduce that the diffeomorphism is transitive.


title: Quark Diffusion Along the Critical Line

abstract:
  The quark diffusion coefficient in the critical window near $T_c$ and at
moderate values of the chemical potential is evaluated.


title:
Microscopics of disordered two-dimensional electron gases under high
  magnetic fields: Equilibrium properties and dissipation in the hydrodynamic
  regime

abstract:
  We develop in detail a new formalism [as a sequel to the work of T. Champel
and S. Florens, Phys. Rev. B 75, 245326 (2007)] that is well-suited for
treating quantum problems involving slowly-varying potentials at high magnetic
fields in two-dimensional electron gases. For an arbitrary smooth potential we
show that electronic Green's function is fully determined by closed recursive
expressions that take the form of a high magnetic field expansion in powers of
the magnetic length l_B. For illustration we determine entirely Green's
function at order l_B^3, which is then used to obtain quantum expressions for
the local charge and current electronic densities at equilibrium. Such results
are valid at high but finite magnetic fields and for arbitrary temperatures, as
they take into account Landau level mixing processes and wave function
broadening. We also check the accuracy of our general functionals against the
exact solution of a one-dimensional parabolic confining potential,
demonstrating the controlled character of the theory to get equilibrium
properties. Finally, we show that transport in high magnetic fields can be
described hydrodynamically by a local equilibrium regime and that dissipation
mechanisms and quantum tunneling processes are intrinsically included at the
microscopic level in our high magnetic field theory. We calculate microscopic
expressions for the local conductivity tensor, which possesses both transverse
and longitudinal components, providing a microscopic basis for the
understanding of dissipative features in quantum Hall systems.


title: Millions of Standard Models on Z6-prime?

abstract:
  Using previous results on the statistics of intersecting D6-brane models on
T^6/Z_6' we analyse solutions that resemble the gauge group and matter content
of the supersymmetric standard model. In particular the structure of the hidden
sector, the gauge coupling constants and chiral exotic matter content are
computed and classified for all possible standard model-like configurations on
this background. It turns out that the number of chiral exotics, Higgses and
values of gauge couplings are strongly correlated. Some examples with the
chiral spectrum of the supersymmetric standard model plus vector-like states
and a massless U(1) B-L are discussed in detail.


title: Baryons with holography

abstract:
  We perform the first study of baryons in holographic QCD with
$D4/D8/\bar{D8}$ multi-$D$ brane system in type IIA superstring theory. The
baryon is described as a chiral soliton solution in the four-dimensional meson
effective action derived from holographic QCD. We also present a brief review
of the holographic model from the viewpoints of recent hadron physics and QCD
phenomenologies.


title: Baryonic matter in holographic QCD

abstract:
  We study baryons and baryonic matter in holographic QCD with $D4/D8/\bar{D8}$
multi-$D$ brane system. In large-$N_c$ holographic QCD, the baryon appears as a
topologically non-trivial chiral soliton, which is called ``brane-induced
Skyrmion''. We also analyze the features of the baryonic matter in holographic
QCD by investigating the system of single brane-induced Skyrmion on a
three-dimensional closed manifold $S^3$. We propose a new interesting picture
of ``pion dominance'' near the critical density.


title:
Nonlinear random gravity. I. Stochastic gravitational waves and
  spontaneous conformal fluctuations due to the quantum vacuum

abstract:
  We investigate the problem of metric fluctuations in the presence of the
vacuum fluctuations of matter fields and critically assess the usual assertion
that vacuum energy implies a Planckian cosmological constant. A new stochastic
classical approach to the quantum fluctuations of spacetime is developed. The
work extends conceptually Boyer's random electrodynamics to a theory of random
gravity but has a considerably richer structure for inheriting nonlinearity
from general relativity. Attention is drawn to subtleties in choosing boundary
conditions for metric fluctuations in relation to their dynamical consequences.
Those compatible with the observed Lorentz invariance must allow for
spontaneous conformal fluctuations, in addition to stochastic gravitational
waves due to zero point gravitons. This is implemented through an effective
metric defined in terms of the random spacetime metric modulo a fluctuating
conformal factor. It satisfies an effective Einstein equation coupled to an
effective stress-energy tensor incorporating gravitational self energy of
metric fluctuations as well as matter fields. The effective Einstein equation
is expanded up to second order nonlinearity. A UV-cutoff is introduced whose
specific value, however, does not enter into the resulting description of
random gravity. The averaged effective metric satisfies the empty space
Einstein equation with an effective cosmological constant. This vanishes when
only the massless matter fields are included. More generally, a finite
effective cosmological constant compatible with the observational constraints
can be obtained as long as the bare masses of the massive matter fields are
nearly zero, or the conformal invariance of matter is restored at some high
energy scale.


title:
W Pair Production at the LHC - II. One-loop Squared Corrections in the
  High Energy Limit

abstract:
  We present the result for the one-loop squared virtual QCD corrections to the
W boson pair production in the quark-anti-quark-annihilation channel in the
limit where all kinematical invariants are large compared to the mass of the W
boson. The infrared pole structure is in agreement with the prediction of
Catani's general formalism for the singularities of QCD amplitudes.


title: Detection of transverse entanglement in phase space

abstract:
  Transverse entanglement between pairs of photons can be detected through
intensity correlation measurements in the near and far fields. We show
theoretically and experimentally that at intermediate zones, it is also
possible to detect transverse entanglement performing only intensity
correlation measurements. Our results are applicable to a number of physical
systems.


title: Evidence for polar jets as precursors of polar plume formation

abstract:
  Observations from the Hinode/XRT telescope and STEREO/SECCHI/EUVI are
utilized to study polar coronal jets and plumes. The study focuses on the
temporal evolution of both structures and their relationship. The data sample,
spanning April 7-8 2007, shows that over 90% of the 28 observed jet events are
associated with polar plumes. EUV images (STEREO/SECCHI) show plume haze rising
from the location of approximately 70% of the polar X-ray (Hinode/XRT) and EUV
jets, with the plume haze appearing minutes to hours after the jet was
observed. The remaining jets occurred in areas where plume material previously
existed causing a brightness enhancement of the latter after the jet event.
Short-lived, jet-like events and small transient bright points are seen (one at
a time) at different locations within the base of pre-existing long-lived
plumes. X-ray images also show instances (at least two events) of
collimated-thin jets rapidly evolving into significantly wider plume-like
structures that are followed by the delayed appearance of plume haze in the
EUV. These observations provide evidence that X-ray jets are precursors of
polar plumes, and in some cases cause brightenings of plumes. Possible
mechanisms to explain the observed jet and plume relationship are discussed.


title: A Filtration of (q,t)-Catalan numbers

abstract:
  We define new generalizations of (q,t)-Catalan numbers applying nabla
operator on k-Schur functions indexed by column partitions. In some special
cases, we give a combinatorial interpretation of these numbers using
configurations of Dyck paths. In some other special cases, we also interpret
these new polynomial as Hilbert series of explicit sub-modules of the
alternating diagonal harmonics built using differential operators.


title: Deeply Virtual Compton Scattering at HERA and perspectives at CERN

abstract:
  Standard parton distribution functions contain neither information on the
correlations between partons nor on their transverse motion, then a vital
knowledge about the three dimensional structure of the nucleon is lost. Hard
exclusive processes, in particular DVCS, are essential reactions to go beyond
this standard picture. In the following, we examine the most recent data in
view of the dipole model predictions and their implication on the quarks/gluons
imaging (tomography) of the nucleon.


title:
A fast and efficient gene-network reconstruction method from multiple
  over-expression experiments

abstract:
  Reverse engineering of gene regulatory networks presents one of the big
challenges in systems biology. Gene regulatory networks are usually inferred
from a set of single-gene over-expressions and/or knockout experiments.
Functional relationships between genes are retrieved either from the steady
state gene expressions or from respective time series. We present a novel
algorithm for gene network reconstruction on the basis of steady-state
gene-chip data from over-expression experiments. The algorithm is based on a
straight forward solution of a linear gene-dynamics equation, where
experimental data is fed in as a first predictor for the solution. We compare
the algorithm's performance with the NIR algorithm, both on the well known
E.Coli experimental data and on in-silico experiments. We show superiority of
the proposed algorithm in the number of correctly reconstructed links and
discuss computational time and robustness. The proposed algorithm is not
limited by combinatorial explosion problems and can be used in principle for
large networks of thousands of genes.


title: A general catalogue of extended objects in the Magellanic System

abstract:
  We update the SMC, Bridge, and LMC catalogues of extended objects that were
constructed by members of our group from 1995 to 2000. In addition to the rich
subsequent literature for the previous classes, we now also include HI shells
and supershells. A total of 9305 objects were cross-identified, while our
previous catalogues amounted to 7900 entries, an increase of $\approx12%$. We
present the results in subcatalogues containing 1445 emission nebulae, 3740
star clusters, 3326 associations, and 794 HI shells and supershells. Angular
and apparent size distributions of the extended objects are analysed. We
conclude that the objects, in general, appear to respond to tidal effects
arising from the LMC, SMC, and Bridge. Number-density profiles extracted along
directions parallel and perpendicular to the LMC bar, can be described by two
exponential-disks. A single exponential-disk fits the equivalent SMC profiles.
Interestingly, when angular-averaged number-densities of most of the extended
objects are considered, the profiles of both Clouds do not follow an
exponential-disk. Rather, they are best described by a tidally-truncated,
core/halo profile, despite the fact that the Clouds are clearly disturbed
disks. On the other hand, the older star clusters taken isolately, distribute
as an exponential disk. The present catalogue is an important tool for the
unambiguous identification of previous objects in current CCD surveys and to
establish new findings.


title: Rayleigh-Plateau instability causes the crown splash

abstract:
  The impact of a drop onto a liquid layer and the subsequent splash has
important implications for diverse physical processes such as air-sea gas
transfer, cooling, and combustion. In the {\it crown splash} parameter regime,
the splash pattern is highly regular. We focus on this case as a model for the
mechanism that leads to secondary droplets, and thus explain the drop size
distribution resulting from the splash. We show that the mean number of
secondary droplets is determined by the most unstable wavelength of the
Rayleigh-Plateau instability. Variations from this mean are governed by the
width of the spectrum. Our results for the crown splash will provide the basis
for understanding more complicated splashes.


title: The Harmonic Oscillator in Quantum Mechanics: A Third Way

abstract:
  Courses on undergraduate quantum mechanics usually focus on solutions of the
Schr\"odinger equation for several simple one-dimensional examples. When the
notion of a Hilbert space is introduced only academic examples are used, such
as the matrix representation of Dirac's raising and lowering operators or the
angular momentum operators. We introduce some of the same one-dimensional
examples as matrix diagonalization problems, with a basis that consists of the
infinite set of square well eigenfunctions. Undergraduate students are well
equipped to handle such problems in familiar contexts. We pay special attention
to the one-dimensional harmonic oscillator. This paper should equip students to
obtain the low lying bound states of any one-dimensional short range potential.

categories: quant-ph cond-mat.other physics.ed-ph physics.gen-ph


title: Nonrotating black hole in a post-Newtonian tidal environment

abstract:
  We examine the motion and tidal dynamics of a nonrotating black hole placed
within a post-Newtonian external spacetime. The tidal perturbation created by
the external environment is treated as a small perturbation. At a large
distance from the black hole, the gravitational field of the external
distribution of matter is assumed to be sufficiently weak to be adequately
described by the (first) post-Newtonian approximation to general relativity.
There, the black hole is treated as a monopole contribution to the total
gravitational field. There exists an overlap in the domains of validity of each
description, and the black-hole and post-Newtonian metrics are matched in the
overlap. The matching procedure produces the equations of motion for the black
hole and the gravito-electric and gravito-magnetic tidal fields acting on the
black hole. We first calculate the equations of motion and tidal fields by
making no assumptions regarding the nature of the post-Newtonian environment;
this could contain a continuous distribution of matter or any number of
condensed bodies. We next specialize our discussion to a situation in which the
black hole is a member of a post-Newtonian two-body system. As an application
of our results, we examine the geometry of the deformed event horizon and
calculate the tidal heating of the black hole, the rate at which it acquires
mass as a result of its tidal interaction with the companion body.


title: Isoperimetry and Symmetrization for Sobolev spaces on metric spaces

abstract:
  Using isoperimetry we obtain new symmetrization inequalities that allow us to
provide a unified framework to study Sobolev inequalities in metric spaces. The
applications include concentration inequalities, as well as metric versions of
the P\'{o}% lya-Szeg\"{o} and Faber-Krahn principles.


title:
Spherically-symmetric Accretion onto a Black Hole at the Center of a
  Young Stellar Cluster

abstract:
  We present a self-consistent, bimodal stationary solution for spherically
symmetric flows driven by young massive stellar clusters with a central
supermassive black hole. We demonstrate that the hydrodynamic regime of the
flow depends on the location of the cluster in the 3D (star cluster mechanical
luminosity - BH mass - star cluster radius) parameter space. We show that a
threshold mechanical luminosity (L_crit) separates clusters which evolve in the
BH dominated regime frome those whose internal structure is strongly affected
by the radiative cooling. In the first case(below the threshold energy) gravity
of the BH separates the flow into two distinct zones: the inner accretion zone
and the outer zone where the star cluster wind is formed. In the second case
(above the critical luminosity), catastrophic cooling sets in inside the
cluster. In this case the injected plasma becomes thermally unstable that
inhibits a complete stationary solution. We compared the calculated accretion
rates and the BH luminosities with those predicted by the classic Bondi
accretion theory and found that Bondi's theory is in good agreement with our
results in the case of low mass clusters. However, it substantially
underestimates the accretion rates and BH luminosities if the star cluster
mechanical luminosity, L_sc, approaches the threshold value (L_sc > 0.1
L_crit).


title:
Selective Heating Mechanism of Magnetic Metal Oxides by Alternating
  Magnetic Field in Microwave Sintering Process

abstract:
  The mechanism of rapid and selective heating of magnetic metal oxides under
the magnetic field of microwaves which continues beyond the Curie temperature $
T_{c} $ is identified by using the Heisenberg model. Monte Carlo calculations
based on the energy principle show that such heating is caused by non-resonant
response of electron spins in the unfilled 3d shell to the wave magnetic field.
Small spin reorientation thus generated leads to a large internal energy change
through the exchange interactions between spins, which becomes maximal around $
T_{c} $ for magnetite $ {\rm Fe}_{3}{\rm O}_{4} $. The dissipative spin
dynamics simulation yields the imaginary part of the magnetic susceptibility,
which becomes largest around $ T_{c} $ and for the microwave frequency around 2
GHz. Hematite $ {\rm Fe}_{2}{\rm O}_{3} $ with weak spontaneous magnetization
responds much less to microwaves as observed in experiments. The heating of
titanium oxide by microwave magnetic field only when oxygen defects are present
is also explained by our theory in terms of the absence of spontaneous
magnetization.


title: Syzygies of the secant variety of a curve

abstract:
  We show that the secant variety of a linearly normal smooth curve of degree
at least 2g+3 is arithmetically Cohen-Macaulay, and we use this information to
study the graded Betti numbers of the secant variety.


title:
On discrete features of the wave equation in singular pp-wave
  backgrounds

abstract:
  We analyze the wave equation in families of pp-wave geometries developing
strong localized scale-invariant singularities in certain limits. For both
cases of well-localized pp-waves and the so-called null-cosmologies, we observe
an intriguing discrete dependence of the existence of a singular limit on the
normalization of the pp-wave profile. We also find restrictive matching
conditions relating the geometries before and after the singularity (if a
singular limit for the solutions of the wave equation with initial conditions
specified away from the near-singular region is assumed to exist).


title: Random circuits by measurements on weighted graph states

abstract:
  Random quantum circuits take an input quantum state and randomize it. This is
a task with a growing number of identified uses in quantum information
processing. We suggest a scheme to implement random circuits in a weighted
graph state. The input state is entangled with the weighted graph state and a
random circuit is implemented when the experimenter performs local measurements
in one fixed basis only. The scheme uses no classical random numbers and is a
new and natural application of weighted graph states


title: Entanglement spectrum in one-dimensional systems

abstract:
  We derive the distribution of eigenvalues of the reduced density matrix of a
block of length l in a one-dimensional system in the scaling regime. The
resulting "entanglement spectrum" is described by a universal scaling function
depending only on the central charge of the underlying conformal field theory.
This prediction is checked against exact results for the XX chain. We also show
how the entanglement gap closes when l is large.

categories: cond-mat.str-el cond-mat.stat-mech hep-th quant-ph


title: Higher Order Birkhoff Averages

abstract:
  There are well-known examples of dynamical systems for which the Birkhoff
averages with respect to a given observable along some or all of the orbits do
not converge. It has been suggested that such orbits could be classified using
higher order averages. In the case of a bounded observable, we show that a
classical result of G.H. Hardy implies that if the Birkhoff averages do not
converge, then neither do the higher order averages.
  If the Birkhoff averages do not converge then we may denote by
$[\alpha_k,\beta_k]$ the limit set of the $k$-th order averages. The sequence
of intervals thus generated is nested: $[\alpha_{k+1},\beta_{k+1}] \subset
[\alpha_k,\beta_k]$. We can thus make a distinction among nonconvergent
Birkhoff averages; either:
  B1. $\cap_{k=1}^\infty [\alpha_k,\beta_k]$ is a point $B_\infty$, or,
  B2. $\cap_{k=1}^\infty [\alpha_k,\beta_k]$ is a non-trivial interval
  $[\alpha_\infty,\beta_\infty]$.
  We give characterizations of the types B1 and B2 in terms of how slowly they
oscillate and we give examples that exhibit both behaviours B1 and B2 in the
context of full shifts on finite symbols and "Bowen's example". For finite full
shifts, we show that the set of orbits with type B2 behaviour has full
topological entropy.


title: Compactness of Weak Radio Sources at High Frequencies

abstract:
  We have obtained 8.4 GHz VLBA observations of a 31-GHz complete sample of
~100 sources between 10 and 100 mJy. The main goals of these observations are:
to determine the angular size, radio spectra and identification for a weak
sample of high frequency sources; to find the fraction of sources which have
sufficiently compact emission for use as calibrators for VLBI observations; and
for design considerations of the proposed DSN Array. We find that a large
fraction of observed sources have VLBI detections. A majority of these sources
have most of their emission in a compact <1 mas radio core, with remaining
sources having steep radio spectra. The source list was provided from GBT
observations to remove discrete sources in the CBI fields.


title: Dimer-dimer collisions at finite energies in two-component Fermi gases

abstract:
  We introduce a major theoretical generalization of existing techniques for
handling the three-body problem that accurately describes the interactions
among four fermionic atoms. Application to a two-component Fermi gas accurately
determines dimer-dimer scattering parameters at finite energies and can give
deeper insight into the corresponding many-body phenomena. To account for
finite temperature effects, we calculate the energy-dependent complex
dimer-dimer scattering length, which includes contributions from elastic and
inelastic collisions. Our results indicate that strong finite-energy effects
and dimer dissociation are crucial for understanding the physics in the
strongly interacting regime for typical experimental conditions. While our
results for dimer-dimer relaxation are consistent with experiment, they confirm
only partially a previously published theoretical result.


title: Berezin-Toeplitz quantization on Lie groups

abstract:
  Let K be a connected compact semisimple Lie group and Kc its
complexification. The generalized Segal-Bargmann space for Kc, is a space of
square-integrable holomorphic functions on Kc, with respect to a K-invariant
heat kernel measure. This space is connected to the "Schrodinger" Hilbert space
L^2(K) by a unitary map, the generalized Segal-Bargmann transform. This paper
considers certain natural operators on L^2(K), namely multiplication operators
and differential operators, conjugated by the generalized Segal-Bargmann
transform. The main results show that the resulting operators on the
generalized Segal-Bargmann space can be represented as Toeplitz operators. The
symbols of these Toeplitz operators are expressed in terms of a certain
subelliptic heat kernel on Kc. I also examine some of the results from an
infinite-dimensional point of view based on the work of L. Gross and P.
Malliavin.


title:
Identifying critical residues in protein folding: Insights from
  phi-value and Pfold analysis

abstract:
  We apply a simulational proxy of the phi-value analysis and perform extensive
mutagenesis experiments to identify the nucleating residues in the folding
reactions of two small lattice Go polymers with different native geometries.
These results are compared with those obtained from an accurate analysis based
on the reaction coordinate folding probability Pfold, and on structural
clustering methods. For both protein models, the transition state ensemble is
rather heterogeneous and splits-up into structurally different populations. For
the more complex geometry the identified subpopulations are actually
structurally disjoint. For the less complex native geometry we found a broad
transition state with microscopic heterogeneity. For both geometries, the
identification of the folding nucleus via the Pfold analysis agrees with the
identification of the folding nucleus carried out with the phi-value analysis.
For the most complex geometry, however, the apllied methodologies give more
consistent results than for the more local geometry. The study of the
transition state' structure reveals that the nucleus residues are not
necessarily fully native in the transition state. Indeed, it is only for the
more complex geometry that two of the five critical residues show a
considerably high probability of having all its native bonds formed in the
transition state. Therefore, one concludes that in general the phi-value
correlates with the acceleration/deceleration of folding induced by mutation,
rather than with the degree of nativeness of the transition state, and that the
traditional interpretation of phi-values may provide a more realistic picture
of the structure of the transition state only for more complex native
geometries.


title:
Researches on Non-standard Optics for Advanced Gravitational Waves
  Interferometers

abstract:
  This thesis presents a collection of different researches on non-standard
optics in view of enhancing the performances of the Advanced Gravitational
waves interferometric detectors, where the thermal noise of the test masses is
expected to be a limiting factor for their sensitivity.
  We provide a quantitative analysis of the impact of non-Gaussian beams on
different kinds of thermal noises. We developed the theory of mesa beam, in
view of a future implementation in advanced GW interferometers of the mesa beam
idea, focusing on the analytical derivation of the quantities (i.e. beam width,
divergence, propagation factor), which are chosen as ISO standard reference
parameters for the characterization of an optical beam. We also analytically
proved a new duality relation between optical cavities with non-spherical
mirrors. The interest of the GW community in this new beam technology led us to
the construction and testing of a prototype mesa beam Fabry-Perot cavity with
Mexican-hat mirror. Part of the work of this thesis was devoted to the
development of new simulation programs of optical systems. These programs
provided the theoretical expected behaviour of our experiment, in particular
cavity modes structure and misalignments sensitivity to be confronted with the
experimental results. We also explored another complementary way of reducing
the mirror thermal noise, beside the beam shaping, that is the multi-layered
coating thickness optimization. We show it to be effective in reducing the
coating noise and explore the possible implications for GW interferometers in
terms of sensitivity. During this analysis we developed an independent model
for the coating effective elastic parameters, which is based on the well
understood subject of homogenization theory.


title:
Space-time anisotropy: theoretical issues and the possibility of an
  observational test

abstract:
  The specific astrophysical data collected during the last decade causes the
need for the modification of the expression for the Einstein-Hilbert action,
and several attempts sufficing this need are known. The modification suggested
in this paper stems from the possible anisotropy of space-time and this means
the natural change of the simplest scalar in the least action principle. To
provide the testable support to this idea, the optic-metrical parametric
resonance is regarded - an experiment on the galactic scale based on the
interaction between the electromagnetic radiation of cosmic masers and
periodical gravitational waves emitted by close double systems or pulsars.
Since the effect depends on the space-time metric, the possible anisotropy
could reveal itself through observations. To give the corresponding theory
predicting the corrections to the expected results of the experiment, the
specific mathematical formalism of Finsler geometry was chosen. It was found
that in case the anisotropy of the space-time exists, the orientation of the
astrophysical systems suitable for observations would show it. In the obtained
geodesics equation there is a direction dependent term.


title: A B-spline Galerkin method for the Dirac equation

abstract:
  The B-spline Galerkin method is investigated for the simple eigenvalue
problem, $y^{\prime\prime} = -\lambda^2 y$. Special attention is give to
boundary conditions. From this analysis, we propose a stable method for the
Dirac equation and evaluate its accuracy by comparing the computed and exact
R-matrix for a wide range of nuclear charges $Z$ and angular quantum numbers
$\kappa$. No spurious solutions were found and excellent agreement was obtained
for the R-matrix.


title: The algebraic concordance order of a knot

abstract:
  Levine defined the rational algebraic knot concordance group and proved that
each nontrivial element is of order two, of order four, or of infinite order.
The determination of the order of an element depends on a p-adic analysis for
all primes p. Here we develop effective means to determine the order of any
element that is in the image of the integral algebraic concordance group by
restricting the set of primes that need to be considered and by finding simple
tests that often avoid p-adic considerations. The paper includes an outline of
how the results apply to give the determination of the algebraic orders of all
2,977 prime knots of 12 or fewer crossings. The paper also includes a short
expository account of the necessary background in p-adic numbers and Witt
groups of bilinear forms.


title:
The two-spinon transverse structure factor of the gapped Heisenberg
  antiferromagnetic chain

abstract:
  We consider the transverse dynamical structure factor of the anisotropic
Heisenberg spin-1/2 chain (XXZ model) in the gapped antiferromagnetic regime
($\Delta > 1$). Specializing to the case of zero field, we use two independent
approaches based on integrability (one valid for finite size, the other for the
infinite lattice) to obtain the exact two-spinon part of this correlator. We
discuss in particular its asymmetry with respect to the $\pi/2$ momentum line,
its overall anisotropy dependence, and its contribution to sum rules.


title: Chiral geometries of (2+1)-d AdS gravity

abstract:
  Pure gravity in (2+1)-dimensions with negative cosmological constant is
classically equivalent Chern-Simons gauge theory with gauge group SO(2; 2),
which may be realized on chiral and antichiral gauge connections. This paper
looks at half-AdS geometries i.e. those with a trivial rightmoving gauge
connection while the left-moving connection is a standard (Banados-Teitelboim-
Zanelli) BTZ connection. These are shown to be related by diffeomorphism to a
BTZ geometry with different mass and angular momentum. Generically this is
over-spinning, leading to a naked closed timelike curves. Other closely related
solutions are also studied. These results suggest that the measure of the
Chern-Simons path integral cannot factorize in a chiral way, if it is to
represent a sum over physically sensible states.


title:
A Survey of Metal Lines at High-redshift (II) : SDSS Absorption Line
  Studies - OVI line density, space density and gas metallicity at z_abs ~ 3.0

abstract:
  We have analysed a large data set of OVI absorber candidates found in the
spectra of 3702 SDSS quasars, focusing on a subsample of 387 AGN sightlines
with an average S/N>5.0, allowing for detection of absorbers above rest-frame
equivalents widths W_r>0.19 A for the OVI 1032 A component. Accounting for
random interlopers mimicking an OVI doublet, we derive for the first time a
secure lower limit for the redshift number density $\Delta N / \Delta z$ for
redshifts z_abs>2.8. With extensive Monte Carlo simulations we quantify the
losses of absorbers due to blending with the ubiquitous Lyman forest lines, and
estimate the success rate of retrieving each individual candidate as a function
of its redshift, the emission redshift of the quasar, the strength of the
absorber and the measured S/N of the spectrum by modelling typical Ly forest
spectra. These correction factors allow us to derive the 'incompleteness and
S/N corrected' redshift number densities of OVI absorbers :$\Delta N _{OVI, c}
/ \Delta z_{c} (2.8 < z < 3.2) = 4.6+-0.3, at 3.2 < z < 3.6 = 6.7+-0.8,and at
3.6 < z < 4.0 = 8.4+-2.9. We can place a secure lower limit for the
contribution of OVI to the closure mass density at the redshifts probed here:
$\Omega _{OVI} (2.8 < z < 3.2) >1.9x10^{-8} h^-1. We show that the strong lines
we probe account for over 65\% of the mass in the OVI absorbers; the weak
absorbers, while dominant in line number density, do not contribute
significantly to the mass density. Making a conservative assumption about the
ionisation fraction, and adopting the Anders (1989) solar abundance values, we
derive the mean metallicty of the gas probed in our search : $\zeta (2.8 < z <
3.2) > 3.6 x 10^-4 h, in good agreement with other studies. These results
demonstrate that large spectroscopic datasets such as SDSS can play an
important role in QSO absorption line studies, in spite of the relatively low
resolution.


title:
A 500 kpc HI Extension of the Virgo Pair NGC4532/DDO137 Detected by the
  Arecibo Legacy Fast ALFA (ALFALFA) Survey

abstract:
  We report the discovery of a ~500 kpc HI extension southwest of the Virgo
Cluster HI-rich pair NGC 4532/DDO 137, detected as part of the Arecibo Legacy
Fast ALFA (ALFALFA) Survey. The feature is the longest and most massive HI tail
structure so far found in the Virgo Cluster and, at 1.8 Mpc from M87, the most
distant from the main concentration of the intracluster medium. The structure
is spatially and spectrally separated into two ridges and is defined by diffuse
emission and discrete clumps of mass 2.5 - 6.8 x 10**7 solar masses. All
emission is blue-shifted with respect to the NGC 4532/DDO 137 pair emission.
Including diffuse emission, the structure has a total mass of up to 7 x 10**8
solar masses, equivalent to ~10% of the system's HI mass. Optical R-band
imaging finds no counterparts to a level of 26.5 mag arcsec**-2. The
characteristics of the structure appear most consistent with a tidal origin.


title: Graphs of bounded degree and the $p$-harmonic boundary

abstract:
  Let $p$ be a real number greater than one and let $G$ be a connected graph of
bounded degree. In this paper we introduce the $p$-harmonic boundary of $G$. We
use this boundary to characterize the graphs $G$ for which the constant
functions are the only $p$-harmonic functions on $G$. It is shown that any
continuous function on the $p$-harmonic boundary of $G$ can be extended to a
function that is $p$-harmonic on $G$. Some properties of this boundary that are
preserved under rough-isometries are also given. Now let $\Gamma$ be a finitely
generated group. As an application of our results we characterize the vanishing
of the first reduced $\ell^p$-cohomology of $\Gamma$ in terms of the
cardinality of its $p$-harmonic boundary. We also study the relationship
between translation invariant linear functionals on a certain difference space
of functions on $\Gamma$, the $p$-harmonic boundary of $\Gamma$ with the first
reduced $\ell^p$-cohomology of $\Gamma$.


title: Marginal distributions for cosmic variance limited CMB polarization data

abstract:
  We provide computationally convenient expressions for all marginal
distributions of the polarization CMB power spectrum distribution
P(C_l|sigma_l), where C_l = {C_l^TT, C_l^TE, C_l^EE, C_l^BB} denotes the set of
ensemble averaged polarization CMB power spectra, and sigma_l = {sigma_l^TT,
sigma_l^TE, sigma_l^EE, sigma_l^BB} the set of the realization specific
polarization CMB power spectra. This distribution describes the CMB power
spectrum posterior for cosmic variance limited data. The expressions derived
here are general, and may be useful in a wide range of applications. Two
specific applications are described in this paper. First, we employ the derived
distributions within the CMB Gibbs sampling framework, and demonstrate a new
conditional CMB power spectrum sampling algorithm that allows for different
binning schemes for each power spectrum. This is useful because most CMB
experiments have very different signal-to-noise ratios for temperature and
polarization. Second, we provide new Blackwell-Rao estimators for each of the
marginal polarization distributions, which are relevant to power spectrum and
likelihood estimation. Because these estimators represent marginals, they are
not affected by the exponential behaviour of the corresponding joint
expression, but converge quickly.


title: The QSO proximity effect at redshift <z>=2.6 with the FLO approach

abstract:
  We revisit the proximity effect produced by QSOs at redshifts 2.1-3.3
applying the FLO approach (Saitta et al. 2008) to a sample of ~6300 Ly-alpha
lines fitted in 21 high resolution, high signal-to-noise spectra. This new
technique allows to recover the hydrogen density field from the HI column
densities of the lines in the Ly-alpha forest, on the basis of simple
assumptions on the physical state of the gas. To minimize the systematic
uncertainties that could affect the density recovering in the QSO vicinity, we
carefully determined the redshifts of the QSOs in our sample and modelled in
detail their spectra to compute the corresponding ionising fluxes. The mean
density field obtained from the observed spectra shows a significant
over-density in the region within 4 proper Mpc from the QSO position,
confirming that QSOs are hosted in high density peaks. The absolute value of
rho/<rho> for the peak is uncertain by a factor of ~3, depending on the assumed
QSO spectral slope and the minimum HI column density detectable in the spectra.
We do not confirm the presence of a significant over-density extending to
separations of ~15 proper Mpc from the QSO, claimed in previous works at
redshifts <z>=2.5 and 3.8. Our best guess for the UV background ionisation rate
based on the IGM mean density recovered by FLO is Gamma_UVB ~ 10^{-12} s^{-1}.
However, values of Gamma_UVB ~ 3x10^{-12} s^{-1} could be viable if an inverted
temperature-density relation with index alpha=-0.5 is adopted.


title: Precursors in Swift Gamma Ray Bursts with redshift

abstract:
  We study a sample of Gamma-Ray Bursts detected by the Swift satellite with
known redshift which show a precursor in the Swift-BAT light curve. We analyze
the spectra of the precursors and compare them with the time integrated spectra
of the prompt emission. We find neither a correlation between the two slopes
nor a tendency for the precursors spectra to be systematically harder or softer
than the prompt ones. The energetics of the precursors are large: on average,
they are just a factor of a few less energetic (in the source rest frame energy
range 15-150 keV) than the entire bursts. These properties do not depend upon
the quiescent time between the end of the precursor and the start of the main
event. These results suggest that what has been called a "precursor" is not a
phenomenon distinct from the main event, but is tightly connected with it, even
if, in some case, the quiescent time intervals can be longer than 100 seconds.


title: On Quantum Effects in Soft Leptogenesis

abstract:
  It has been recently shown that quantum Boltzman equations may be relevant
for leptogenesis. Quantum effects, which lead to a time-dependent CP asymmetry,
have been shown to be particularly important for resonant leptogenesis when the
asymmetry is generated by the decay of two nearly degenerate states. In this
work we investigate the impact of the use of quantum Boltzman equations in the
framework ``soft leptogenesis'' in which supersymmetry soft-breaking terms give
a small mass splitting between the CP-even and CP-odd right-handed sneutrino
states of a single generation and provide the CP-violating phase to generate
the lepton asymmetry.


title: Can Bell's Prescription for Physical Reality Be Considered Complete?

abstract:
  An experiment is proposed to test Bell's theorem in a purely macroscopic
domain. If realized, it would determine whether Bell inequalities are satisfied
for a manifestly local, classical system. It is stressed why the inequalities
should not be presumed to hold for such a macroscopic system without actual
experimental evidence. In particular, by providing a purely classical,
topological explanation for the EPR-Bohm type spin correlations, it is
demonstrated why Bell inequalities must be violated in the manifestly local,
macroscopic domain, just as strongly as they are in the microscopic domain.


title:
Revisiting the radio/X-ray flux correlation in the black hole V404 Cyg:
  from outburst to quiescence

abstract:
  We report results of Chandra X-ray and VLA radio observations of the Galactic
accreting black hole V404 Cyg (GS 2023+338) in its quiescent state. V404 Cyg is
detected at its faintest level of radio and X-ray emission with a 0.5-10 keV
unabsorbed luminosity of 8.3 x 10^32 (d/3.5 kpc)^2 erg/s. The X-ray spectrum
fit with an absorbed power-law model yields a photon index of 2.17 +/- 0.13.
Contrary to previous findings, this clearly indicates that V404 Cyg undergoes -
like most black holes in quiescence - a softening of its X-ray spectrum at very
low luminosity compared to the standard hard state. The quiescent radio
emission is consistent with the presence of self-absorbed compact jets. We have
also reanalyzed archival data from the decay of the 1989 outburst of V404 Cyg
in order to quantify more precisely the correlation between radio and X-ray
emission in the hard state of V404 Cyg. We show that this correlation extends
over five decades in X-ray flux and holds down to the quiescent state of V404
Cyg. The index of this correlation (~0.5) may suggest that synchrotron
self-Compton emission is the dominant physical process at high energy in V404
Cyg. However, this index is also consistent with scale invariant jet models
coupled to an inefficiently radiating accretion disc. We discuss the properties
of the quiescent state of black holes and highlight the fact that some of their
properties are different from the standard hard state.


title: MOND plus classical neutrinos not enough for cluster lensing

abstract:
  Clusters of galaxies offer a robust test bed for probing the nature of dark
matter that is insensitive to the assumption of the gravity theories. Both
Modified Newtonian Dynamics (MOND) and General Relativity (GR) would require
similar amounts of non-baryonic matter in clusters as MOND boosts the gravity
only mildly on cluster scales. Gravitational lensing allows us to estimate the
enclosed mass in clusters on small (20 - 50 kpc) and large (several 100 kpc)
scales independent of the assumptions of equilibrium. Here we show for the
first time that a combination of strong and weak gravitational lensing effects
can set interesting limits on the phase space density of dark matter in the
centers of clusters. The phase space densities derived from lensing
observations are inconsistent with neutrino masses ranging from 2 - 7 eV, and
hence do not support the 2 eV-range particles required by MOND. To survive,
plausible modifications for MOND may be either an additional degree of
dynamical freedom in a co-variant incarnation or mass-varying theories of
neutrinos.


title:
Strong Limit on a Variable Proton-to-Electron Mass Ratio from Molecules
  in the Distant Universe

abstract:
  The Standard Model of particle physics assumes that the so-called fundamental
constants are universal and unchanging. Absorption lines arising in molecular
clouds along quasar sightlines offer a precise test for variations in the
proton-to-electron mass ratio, mu, over cosmological time and distance scales.
The inversion transitions of ammonia are particularly sensitive to mu compared
to molecular rotational transitions. Comparing the available ammonia spectra
observed towards the quasar B0218+357 with new, high-quality rotational
spectra, we present the first detailed measurement of mu with this technique,
limiting relative deviations from the laboratory value to |dmu/mu| <
1.8x10^{-6} (95% confidence level) at approximately half the Universe's current
age - the strongest astrophysical constraint to date. Higher-quality ammonia
observations will reduce both the statistical and systematic uncertainties in
these measurements.


title: Anomalous CMB polarization and gravitational chirality

abstract:
  We consider the possibility that gravity breaks parity, with left and right
handed gravitons coupling to matter with a different Newton's constant and show
that this would affect their zero-point vacuum fluctuations during inflation.
Should there be a cosmic background of gravity waves, the effect would
translate into anomalous CMB polarization. Non-vanishing TB (and EB)
polarization components emerge, revealing interesting experimental targets.
Indeed if reasonable chirality is present a TB measurement would provide the
easiest way to detect a gravitational wave background. We speculate on the
theoretical implications of such an observation.


title: Particle propagators on discrete spacetime

abstract:
  A quantum mechanical description of particle propagation on the discrete
spacetime of a causal set is presented. The model involves a discrete path
integral in which trajectories within the causal set are summed over to obtain
a particle propagator. The sum-over-trajectories is achieved by a matrix
geometric series. For causal sets generated by sprinkling points into 1+1 and
3+1 dimensional Minkowski spacetime the propagator calculated on the causal set
is shown to agree, in a suitable sense, with the causal retarded propagator for
the Klein-Gordon equation. The particle propagator described here is a step
towards quantum field theory on causal set spacetime.


title: Spatially resolved H2 emission from the disk around T Tau N

abstract:
  We report the detection of quiescent H2 emission in a spatially resolved
ring-like structure within 100 AU of T Tau N. We present evidence to show that
the emission most likely arises from shocks in the atmosphere of a nearly
face-on disk around T Tau N. Using high spatial resolution 3D spectroscopic
K-band data, we trace the spatial distribution of several H2 NIR rovibrational
lines in the vicinity of T Tau N. We detect weak H2 emission from the v=1-0
S(0), S(1), Q(1) lines and the v=2-1 S(1) line in a ring-like structure around
T Tau N between 0.1'' (~15 AU) and 0.7'' (~100AU) from the star. The v=1-0 S(0)
and v=2-1 S(1) lines are detected only in the outer parts of the ring
structure. Closer to the star, the strong continuum limits our sensitivity to
these lines. The total flux of the v=1-0 S(1) line is 1.8 *10^{-14} ergs
s^{-1}cm^{-2}, similar to previous measurements of H2 in circumstellar disks.
The velocity of the H2 emitting gas around T Tau N is consistent with the rest
velocity of the star, and the H2 does not seem to be part of a collimated
outflow. Both shocks impinging on the surface of a disk and irradiation of a
disk by UV-photons and X-rays from the central star are plausible candidates
for the H2 excitation mechanism. However, irradiation should not create a large
degree of excitation at radii larger than 20 AU. Most likely the H2 emission
arises in the atmosphere of a flared disk with radius 85-100 AU and mass
0.005-0.5Msun, where the gas is excited by shocks created when a wide-angle
wind impinges on the disk. The H2 emission could also originate from shock
excitation in the cavity walls of an envelope, but this requires an unusually
high velocity of the wide-angle wind from T Tau N.


title:
Practical long-distance quantum key distribution system using decoy
  levels

abstract:
  Quantum key distribution (QKD) has the potential for widespread real-world
applications. To date no secure long-distance experiment has demonstrated the
truly practical operation needed to move QKD from the laboratory to the real
world due largely to limitations in synchronization and poor detector
performance. Here we report results obtained using a fully automated, robust
QKD system based on the Bennett Brassard 1984 protocol (BB84) with low-noise
superconducting nanowire single-photon detectors (SNSPDs) and decoy levels.
Secret key is produced with unconditional security over a record 144.3 km of
optical fibre, an increase of more than a factor of five compared to the
previous record for unconditionally secure key generation in a practical QKD
system.


title: A limit-method for solving period problems on minimal surfaces

abstract:
  We introduce a new technique to solve period problems on minimal surfaces
called limit-method. If a family of surfaces has Weierstrass-data converging to
the data of a known example, and this presents a transversal solution of
periods, then the original family contains a sub-family with closed periods.


title:
The seesaw mechanism at TeV scale in the 3-3-1 model with right-handed
  neutrinos

abstract:
  We implement the seesaw mechanism in the 3-3-1 model with right-handed
neutrinos. This is accomplished by the introduction of a scalar sextet into the
model and the spontaneous violation of the lepton number. We identify the
Majoron as a singlet under $SU_L(2)\otimes U_Y(1)$ symmetry, which makes it
safe under the current bounds imposed by electroweak data. The main result of
this work is that the seesaw mechanism works already at TeV scale with the
outcome that the right-handed neutrino masses lie in the electroweak scale, in
the range from MeV to tens of GeV. This window provides a great opportunity to
test their appearance at current detectors, though when we contrast our results
with some previous analysis concerning detection sensitivity at LHC, we
conclude that further work is needed in order to validate this search.


title:
Triply periodic minimal surfaces which converge to the
  Hoffman-Wohlgemuth example

abstract:
  We get a continuous one-parameter new family of embedded minimal surfaces, of
which the period problems are two-dimensional. Moreover, one proves that it has
Scherk second surface and Hoffman-Wohlgemuth example as limit-members.


title:
Surprising dissimilarities in a newly formed pair of 'identical twin'
  stars

abstract:
  The mass and chemical composition of a star are the primary determinants of
its basic physical properties--radius, temperature, luminosity--and how those
properties evolve with time. Thus, two stars born at the same time, from the
same natal material, and with the same mass are 'identical twins,' and as such
might be expected to possess identical physical attributes. We have discovered
in the Orion Nebula a pair of stellar twins in a newborn binary star system.
Each star in the binary has a mass of 0.41 +/- 0.01 solar masses, identical to
within 2 percent. Here we report that these twin stars have surface
temperatures that differ by ~300K (~10%), and luminosities that differ by ~50%,
both at high confidence level. Preliminary results indicate that the stars'
radii also differ, by 5-10%. These surprising dissimilarities suggest that one
of the twins may have been delayed by several hundred thousand years in its
formation relative to its sibling. Such a delay could only have been detected
in a very young, definitively equal-mass binary system3 such as that reported
here. Our findings reveal cosmic limits on the age synchronisation of young
binary stars, often used as tests for the age calibrations of star-formation
models.


title: UV Radiative Feedback During the Advanced Stages of Reionization

abstract:
  The ionizing ultraviolet background (UVB) during reionization can suppress
the gas content of low-mass galaxies, even those capable of efficient atomic
cooling, and thus lead to an extended reionization epoch. In this work, we
explore the importance of negative UV radiative feedback on Tvir > 10^4 K halos
during the middle and late stages of reionization. We do not try to
self-consistently model reionization; instead, we explore a large parameter
space in an attempt to draw general, robust conclusions. We do this using a
tiered approach. Using 1-D hydrodynamical simulations, we model the collapse of
gas onto halos of various masses under UVBs of various intensities. We then
generate realistic, parametrized maps of the inhomogeneous UVB, using
large-scale semi-numeric simulations. By combining these results, we find that
under all reasonably conservative scenarios, UV feedback on atomically-cooled
halos is not strong enough to notably delay the bulk of reionization. Such a
delay is only likely if ionizing efficiencies of z > 10 sources are much higher
(~ two orders of magnitude) than z ~ 6 data seem to imply. We also find that
feedback is very strongly dependent on halo mass. Our results suggest that the
natural time-scale for the bulk of reionization is the growth of the global
collapsed fraction contained in Tvir > 10^4 K halos. Finally, our results
underscore the importance of taking into account extended dynamical ranges when
modeling reionization.


title:
The Theory and Simulation of the 21-cm Background from the Epoch of
  Reionization

abstract:
  The redshifted 21-cm line of distant neutral H atoms provides a probe of the
cosmic ``dark ages'' and the epoch of reionization (``EOR'') which ended them.
The radio continuum produced by this redshifted line can be seen in absorption
or emission against the CMB at meterwaves, yielding information about the
thermal and ionization history of the universe and the primordial density
perturbation spectrum that led to galaxy and large-scale structure formation.
Observing this 21-cm background is a great challenge. A new generation of
low-frequency radio arrays is currently under development to search for this
background. Accurate theoretical predictions of the spectrum and anisotropy of
this background, necessary to guide and interpret future observations, are also
quite challenging. It is necessary to model the inhomogeneous reionization of
the intergalactic medium and determine the spin temperature of the 21-cm
transition and its variations in time and space as it decouples from the
temperature of the CMB. Here, we focus on just a few of the predictions for the
21-cm background from the EOR, based on our newest, large-scale simulations of
patchy reionization. These simulations are the first with enough N-body
particles (from 5 to 29 billion) and radiative transfer rays to resolve the
formation of and trace the ionizing radiation from each of the millions of
dwarf galaxies believed responsible for reionization, down to 10^8 M_solar, in
a cubic volume large enough (90 and 163 comoving Mpc on a side) to make
meaningful statistical predictions of the fluctuating 21-cm background.
(abridged)


title: 0th Order Heavy Quark Photon Bremsstrahlung

abstract:
  We calculate the 0th order in opacity number distribution of massive photons
(gluons) for heavy quark production radiation including interference from the
away-side jet. While consistent with the soft photon (gluon) approximation, we
find that approximating 1-x with 1, as done in previous calculations, strongly
affects the magnitude of energy loss. Restoring gauge invariance by including
the radiation associated with the away-side jet fills in the "dead cone," but
is a relatively small effect. The Ter-Mikayelian reduction from vacuum energy
loss is 10-40% for 5-25 GeV charm and bottom quarks.


title: Bose-Einstein condensation of relativistic Scalar Field Dark Matter

abstract:
  Standard thermodynamical results of ideal Bose gases are used to study the
possible formation of a cosmological Bose-Einstein condensate in Scalar Field
Dark Matter models; the main hypothesis is that the boson particles were in
thermal equilibrium in the early Universe. It is then shown that the only
relevant case needs the presence of both particles and anti-particles, and that
it corresponds to models in which the bosonic particle is very light. Contrary
to common wisdom, the condensate should be a relativistic phenomenon. Some
cosmological implications are discussed in turn.


title:
Electrical stress effect on Josephson tunneling through ultrathin AlOx
  barrier in Nb/Al/AlOx/Nb junctions

abstract:
  The effect of dc electrical stress and breakdown on Josephson and
quasiparticle tunneling in Nb/Al/AlOx/Nb junctions with ultrathin AlOx barriers
typical for applications in superconductor digital electronics has been
investigated. The junctions' conductance at room temperature and
current-voltage (I-V) characteristics at 4.2 K have been measured after the
consecutive stressing of the tunnel barrier at room temperature. Electrical
stress was applied using current ramps with increasing amplitude ranging from 0
to ~1000 Ic corresponding to voltages across the barrier up to 0.65 V where Ic
is the Josephson critical current. A very soft breakdown has been observed with
polarity-dependent breakdown current (voltage). A dramatic increase in subgap
conductance of the junctions, the appearance of subharmonic current steps, and
gradual increase in both the critical and the excess currents as well as a
decrease in the normal-state resistance have been observed. The observed
changes in superconducting tunneling suggest a model in which a progressively
increasing number of defects and associated additional conduction channels
(superconducting quantum point contacts (SQPCs)) are induced by electric field
in the tunnel barrier. By comparing the I-V characteristics of these conduction
channels with the nonstationary theory of current transport in SQPCs based on
multiple Andreev reflections by Averin and Bardas, the typical transparency D
of the induced SQPCs was estimated as D ~ 0.7. The number of induced SQPCs was
found to grow with voltage across the barrier as sinh(V/V_0) with V_0 = 0.045
V, in good agreement with the proposed model of defect formation by ion
electromigration. The observed polarity dependence of the breakdown current
(voltage) is also consistent with the model.


title: On a question of Erdos and Ulam

abstract:
  Ulam asked in 1945 if there is an everywhere dense \emph{rational set}, i.e.
a point set in the plane with all its pairwise distances rational. Erd\H os
conjectured that if a set $S$ has a dense rational subset, then $S$ should be
very special. The only known types of examples of sets with dense (or even just
infinite) rational subsets are lines and circles. In this paper we prove Erd\H
os's conjecture for algebraic curves, by showing that no irreducible algebraic
curve other than a line or a circle contains an infinite rational set.


title: CMB Beam Systematics: Impact on Lensing Parameter Estimation

abstract:
  The CMB's B-mode polarization provides a handle on several cosmological
parameters most notably the tensor-to-scalar ratio, $r$, and is sensitive to
parameters which govern the growth of large scale structure (LSS) and evolution
of the gravitational potential. The primordial gravitational-wave- and
secondary lensing-induced B-mode signals are very weak and therefore prone to
various foregrounds and systematics. In this work we use Fisher-matrix-based
estimations and apply, for the first time, Monte-Carlo Markov Chain (MCMC)
simulations to determine the effect of beam systematics on the inferred
cosmological parameters from five upcoming experiments: PLANCK, POLARBEAR,
SPIDER, QUIET+CLOVER and CMBPOL. We consider beam systematics which couple the
beam substructure to the gradient of temperature anisotropy and polarization
(differential beamwidth, pointing and ellipticity) and beam systematics due to
differential beam normalization (differential gain) and orientation (beam
rotation) of the polarization-sensitive axes (the latter two effects are
insensitive to the beam substructure). We determine allowable levels of beam
systematics for given tolerances on the induced parameter errors and check for
possible biases in the inferred parameters concomitant with potential increases
in the statistical uncertainty. All our results are scaled to the 'worst case
scenario'. In this case and for our tolerance levels, the beam rotation should
not exceed the few-degree to sub-degree level, typical ellipticity is required
to be 1% level, the differential gain allowed level is a few parts in $10^{3}$
to $10^{4}$, differential beamwidth upper limits are of the sub-percent level
and differential pointing should not exceed the few- to sub-arcsec level.


title: Generalised Atmospheric Rosenbluth Methods (GARM)

abstract:
  We show that the classical Rosenbluth method for sampling self-avoiding walks
can be extended to a general algorithm for sampling many families of objects,
including self-avoiding polygons. The implementation relies on an elementary
move which is a generalisation of kinetic growth; rather than only appending
edges to the endpoint, edges may be inserted at any vertex providing the
resulting objects still lie within the same family. We implement this method
using pruning and enrichment to sample self-avoiding walks and polygons. The
algorithm can be further extended by mixing it with length-preserving moves,
such pivots and crank-shaft moves.


title:
Solving the Homogeneous Boltzmann Equation with Arbitrary Scattering
  Kernel

abstract:
  With applications in astroparticle physics in mind, we generalize a method
for the solution of the nonlinear, space homogeneous Boltzmann equation with
isotropic distribution function to arbitrary matrix elements. The method is
based on the expansion of the matrix element in terms of two cosines of the
"scattering angles". The scattering functions used by previous authors in
particle physics for matrix elements in Fermi-approximation are retrieved as
lowest order results in this expansion. The method is designed for the unified
treatment of reactive mixtures of particles obeying different scattering laws,
including the quantum statistical terms for blocking or stimulated emission, in
possibly large networks of Boltzmann equations. Although our notation is the
relativistic one, as it is used in astroparticle physics, the results can also
be applied in the classical case.

categories: astro-ph cond-mat.stat-mech hep-ph math-ph math.MP


title:
On the stability of bubble functions and a stabilized mixed finite
  element formulation for the Stokes problem

abstract:
  In this paper we investigate the relationship between stabilized and enriched
finite element formulations for the Stokes problem. We also present a new
stabilized mixed formulation for which the stability parameter is derived
purely by the method of weighted residuals. This new formulation allows equal
order interpolation for the velocity and pressure fields. Finally, we show by
counterexample that a direct equivalence between subgrid-based stabilized
finite element methods and Galerkin methods enriched by bubble functions cannot
be constructed for quadrilateral and hexahedral elements using standard bubble
functions.


title: Elliptic and parabolic second-order PDEs with growing coefficients

abstract:
  We consider a second-order parabolic equation in $\bR^{d+1}$ with possibly
unbounded lower order coefficients. All coefficients are assumed to be only
measurable in the time variable and locally H\"older continuous in the space
variables. We show that global Schauder estimates hold even in this case. The
proof introduces a new localization procedure. Our results show that the
constant appearing in the classical Schauder estimates is in fact independent
of the $L_{\infty}$-norms of the lower order coefficients. We also give a proof
of uniqueness which is of independent interest even in the case of bounded
coefficients.


title:
Pure-state quantum trajectories for general non-Markovian systems do not
  exist

abstract:
  Since the first derivation of non-Markovian stochastic Schr\"odinger
equations, their interpretation has been contentious. In a recent Letter [Phys.
Rev. Lett. 100, 080401 (2008)], Di\'osi claimed to prove that they generate
"true single system trajectories [conditioned on] continuous measurement". In
this Letter we show that his proof is fundamentally flawed: the solution to his
non-Markovian stochastic Schr\"odinger equation at any particular time can be
interpreted as a conditioned state, but joining up these solutions as a
trajectory creates a fiction.


title: Multi-instanton and string loop corrections in toroidal orbifold models

abstract:
  We analyze N=2 (perturbative and non-perturbative) corrections to the
effective theory in type I orbifold models where a dual heterotic description
is available. These corrections may play an important role in phenomenological
scenarios. More precisely, we consider two particular compactifications: the
Bianchi-Sagnotti-Gimon-Polchinski orbifold and a freely-acting Z_2 x Z_2
orbifold with N=1 supersymmetry and gauge group SO(q) x SO(32-q). By exploiting
perturbative calculations of the physical gauge couplings on the heterotic
side, we obtain multi-instanton and one-loop string corrections to the K\"ahler
potential and the gauge kinetic function for these models. The non-perturbative
corrections appear as sums over relevant Hecke operators, whereas the one-loop
correction to the K\"ahler potential matches the expression proposed in [1,2].
We argue that these corrections are universal in a given class of models where
target-space modular invariance (or a subgroup of it) holds.


title: Clouds, Clumps, Cores & Comets - a Cosmic Chemical Connection?

abstract:
  We discuss the connection between the chemistry of dense interstellar clouds
and those characteristics of cometary matter that could be remnants of it. The
chemical evolution observed to occur in molecular clouds is summarized and a
model for dense core collapse that can plausibly account for the isotopic
fractionation of hydrogen, nitrogen, oxygen and carbon measured in primitive
solar system materials is presented.


title: Magnetic field generation by the stationary accretion shock instability

abstract:
  By adding a weak magnetic field to a spherically symmetric fluid
configuration that caricatures a stalled shock in the post-bounce supernova
environment, we explore the capacity of the stationary accretion shock
instability (SASI) to generate magnetic fields. The SASI develops upon
perturbation of the initial condition, and the ensuing flow generates--{\em in
the absence of rotation}--dynamically significant magnetic fields ($\sim
10^{15}$ G) on a time scale that is relevant for the explosion mechanism of
core-collapse supernovae. We describe our model, present some recent results,
and discuss their potential relevance for supernova models.


title: Knots and Preons

abstract:
  It is shown that the four trefoil solitons that are described by the
irreducible representations D^{3/2}_{mm'} of the quantum algebra SL_q(2) (and
that may be identified with the four families of elementary fermions
(e,\mu,\tau;\nu_e\nu_\mu\nu_\tau;d,s,b;u,c,t) may be built out of three preons,
chosen from two charged preons with charges (1/3,-1/3) and two neutral preons.
These preons are Lorentz spinors and are described by the D^{1/2}_{mm'}
representation of SL_q(2). There are also four bosonic preons described by the
D^1_{mm'} and D^0_{00} representations of SL_q(2). The knotted standard theory
may be replicated at the preon level and the conjectured particles are in
principle indirectly observable.


title:
A 1200-micron MAMBO survey of the GOODS-N field: a significant
  population of submillimetre drop-out galaxies

abstract:
  We present a 1200-micron image of the Great Observatories Origin Deep Survey
North (GOODS-N) field, obtained with the Max Planck Millimeter Bolometer array
(MAMBO) on the IRAM 30-m telescope. The survey covers a contiguous area of 287
square arcmin to a near-uniform noise level of ~0.7mJy/beam. After Bayesian
flux deboosting, a total of 30 sources are recovered (>=3.5sigma). An optimal
combination of our 1200-micron data and an existing 850-micron image from the
Submillimetre Common-User Bolometer Array (SCUBA) yielded 33 sources
(>=4sigma). We combine our GOODS-N sample with those obtained in the Lockman
Hole and ELAIS-N2 fields (Scott et al. 2002; Greve et al. 2004) in order to
explore the degree of overlap between 1200-micron- and 850-micron-selected
galaxies (hereafter SMGs), finding no significant difference between their
850-micron to 1200-micron flux density distributions. However, a noise-weighted
stacking analysis yields a significant detection of the 1200-micron-blank SCUBA
sources, whereas no significant 850-micron signal is found for the
850-micron-blank MAMBO sources. The hypothesis that the 850/1200-micron flux
density distribution of SCUBA sources is also representative of the MAMBO
population is rejected at the ~4sigma level, via Monte Carlo simulations.
Therefore, although the populations overlap, galaxies selected at 850 and
1200micron are different, and there is compelling evidence for a significant
1200-micron-detected population which is not recovered at 850micron. These are
submm drop-outs (SDOs), with S_850/S_1200 = 0.7-1.7, requiring very cold dust
or unusual spectral energy distributions (T_d ~ 10K; beta ~ 1), unless SDOs
reside beyond the redshift range observed for radio-identified SMGs, i.e. at z
> 4.


title:
The initial momentum dependence of the quantum resonance in the
  delta-kicked rotor

abstract:
  The influence of an initial momentum on the appearance of "quantum
resonances" in the delta-kicked rotor system is explored experimentally. We
show that for certain initial momenta, a resonance can be negated entirely,
whereas at others a resonance can be made to appear. At a larger number of
kicks, all resonances are shown to narrow. We show that as a consequence, the
individual "diffraction peaks" may split. We compare our results to numerical
simulations as well as analytical theory.


title:
Dark matter annihilation at cosmological redshifts: possible relic
  signal from annihilation of weakly interacting massive particles

abstract:
  We discuss the possibility to observe the products of dark matter
annihilation that was going on in the early Universe. Of all the particles that
could be generated by this process we consider only photons, as they are both
uncharged and easily detectable. The earlier the Universe was, the higher the
dark matter concentration $n$ and the annihilation rate (proportional to $n^2$)
were. However, the emission from the very early Universe cannot reach us
because of the opacity. The main part of the signal was generated at the moment
the Universe had just become transparent for the photons produced by the
annihilation. Thus, the dark matter annihilation in the early Universe should
have created a sort of relic emission. We obtain its flux and the spectrum.
  If weakly interacting massive particles (WIMPs) constitute dark matter, it is
shown that we may expect an extragalactic gamma-ray signal in the energy range
0.5 - 20 {MeV} with a maximum near 8 {MeV}. We show that an experimentally
observed excess in the gamma-ray background at 0.5 - 20 {MeV} could be created
by the relic WIMPs annihilation only if the dark matter structures in the
universe had appeared before the universe became transparent for the
annihilation products ($z \simeq 300$). We discuss in more detail physical
conditions whereby this interpretation could be possible.


title:
The Bass and Topological Stable Ranks of $H^\infty_\R(\D)$ and
  $A_\R(\D)$

abstract:
  In this note we prove that the Bass stable rank of $H^\infty_\R(\D)$ is two.
This establishes the validity of a conjecture by S. Treil. We accomplish this
in two different ways, one by giving a direct proof, and the other, by first
showing that the topological stable rank of $H^\infty_\R(\D)$ is two. We apply
these results to give new proofs of results by R. Rupp and A. Sasane stating
that the Bass stable rank of $A_\R(\D)$ is two and the topological stable rank
of $A_\R(\D)$ is two, settling a conjecture by the second author. We also
present a $\bar\partial$-free proof of the second author's characterization of
the reducible pairs in $A_\R(\D)$.


title:
Classification of singular Q-homology planes. I. Structure and
  singularities

abstract:
  A Q-homology plane is a normal complex algebraic surface having trivial
rational homology. We obtain a structure theorem for Q-homology planes with
smooth locus of non-general type. We show that if a Q-homology plane contains a
non-quotient singularity then it is a quotient of an affine cone over a
projective curve by an action of a finite group respecting the set of lines
through the vertex. In particular, it is contractible, has negative Kodaira
dimension and only one singular point. We describe minimal normal completions
of such planes.


title: Ricci-Flat and Charged Wormholes in Five Dimensions

abstract:
  We construct stationary Ricci-flat inter-universe Lorentzian wormhole
solutions in all D\ge 5 dimensions that connect two flat asymptotic spacetimes.
Such a solution can be viewed as the gravity dual of a string tachyon state
whose linear momentum is larger than its tension. We focus our analysis on the
D=5 wormholes which are not traversable for the timelike and null geodesics;
however, we demonstrate that there exist accelerated timelike trajectories that
traverse from one asymptotic region to the other. We further study the
minimally-coupled scalar wave equation and demonstrate that the quantum
tunnelling between two worlds must occur. We also obtain charged wormholes in
five-dimensional supergravities. With appropriate choice of parameters, these
wormholes connect AdS$_3\times S^2$ in one asymptotic region to flat
Minkowskian spacetime in the other.


title:
Mirkovic-Vilonen polytopes lying in a Demazure crystal and an opposite
  Demazure crystal

abstract:
  We give a necessary and sufficient condition for an MV polytope $P$ in a
highest weight crystal to lie in an arbitrary fixed Demazure crystal (resp.,
opposite Demazure crystal), in terms of the lengths of edges along a path
through the 1-skeleton of $P$ corresponding to a reduced word for the longest
element of the Weyl group $W$. % Also, we give an explicit description as a
pseudo-Weyl polytope for extremal MV polytopes in a highest weight crystal. %
Finally, by combining the results above, we obtain a polytopal condition for an
MV polytope $P$ to lie in an arbitrary fixed opposite Demazure crystal.


title: Hydrogen and Helium atoms in strong magnetic fields

abstract:
  The energy levels of hydrogen and helium atoms in strong magnetic fields are
calculated in this study. The current work contains estimates of the binding
energies of the first few low-lying states of these systems that are
improvements upon previous estimates. The methodology involves computing the
eigenvalues and eigenvectors of the generalized two-dimensional Hartree-Fock
partial differential equations for these one- and two-electron systems in a
self-consistent manner. The method described herein is applicable to
calculations of atomic structure in magnetic fields of arbitrary strength as it
exploits the natural symmetries of the problem without assumptions of any basis
functions for expressing the wave functions of the electrons or the commonly
employed adiabatic approximation. The method is found to be readily extendable
to systems with more than two electrons.


title: Holographic deconfinement temperature at finite densities

abstract:
  This paper has been withdrawn by the authors and replaced by the revised
version in arXiv:0709.1772.


title: Using rational numbers to key nested sets

abstract:
  This report details the generation and use of tree node ordering keys in a
single relational database table. The keys for each node are calculated from
the keys of its parent, in such a way that the sort order places every node in
the tree before all of its descendants and after all siblings having a lower
index. The calculation from parent keys to child keys is simple, and reversible
in the sense that the keys of every ancestor of a node can be calculated from
that node's keys without having to consult the database.
  Proofs of the above properties of the key encoding process and of its
correspondence to a finite continued fraction form are provided.