title: Pion Form Factor in Improved Holographic QCD Backgrounds

abstract:
  We extend a recent numerical calculation of the pion electromagnetic form
factor F_\pi (Q^2) in holographic QCD to study two important issues regarding
the behavior of fields in the bulk. First, we show that using a chiral
symmetry-breaking field formally satisfying the boundary conditions of the
``soft-wall'' model changes numerical results very little from the earlier
calculation that ignores these constraints. Second, we use a background field
that interpolates between ``hard-wall'' and ``soft-wall'' models to obtain an
improved model that reproduces the desirable phenomenological features of both.
In all cases, F_\pi$ for large Q^2 is shallower than data, an effect that can
be cured by relaxing the fit to one of the static observables, particularly the
decay constant f_\pi.


title: Patterns of Gauge Mediation in Metastable SUSY Breaking

abstract:
  Supersymmetry breaking in a metastable vacuum allows one to build simple and
concrete models of gauge mediation. Generation of gaugino masses requires that
R-symmetry be broken in this vacuum. In general, there are two possible ways to
break R-symmetry, explicitly or spontaneously. We find that the MSSM
phenomenology depends crucially on how this breaking occurs in the Hidden
Sector. Explicit R-symmetry breaking models can lead to fairly standard gauge
mediation, but we argue that in the context of ISS-type models this only makes
sense if B=0 at the mediation scale, which leads to high tan(beta). If on the
other hand, R-symmetry is broken spontaneously, then R-symmetry violating soft
terms tend to be suppressed with respect to R-symmetry preserving ones, and one
is led to a scenario with large scalar masses. These models interpolate between
standard gauge mediation and split SUSY models. We provide benchmark points for
the two scenarios. They demonstrate that the specific dynamics of the Hidden
Sector -- the underlying nature of supersymmetry and R-symmetry breaking --
affects considerably the mass spectrum of the MSSM, and vice versa.


title: Radio-Optical Study of Double-Peaked AGNs. I. 3C 390.3

abstract:
  We aim to test the model proposed to explain the correlation between the flux
density at 15 GHz of a stationary component in the parsec-scale jet and the
optical continuum emission in the radio galaxy 3C~390.3. In the model, the
double-peaked emission from 3C~390.3 is likely to be generated both near the
disk and in a rotating subrelativistic outflow surrounding the jet, due to
ionization of the outflow by the beamed continuum emission from the jet. This
scenario is chosen since broad-emission lines are observed to vary following
changes in the inner radio jet. For recent epochs we have imaged and modelled
the radio emission of the inner jet of 3C~390.3, which was observed with very
long baseline interferometry at 15 GHz, 22 GHz and 43 GHz, to image the inner
part of the parsec-scale jet, locate the exact region where the bulk of the
continuum luminosity is generated and search for the mechanism that drives the
double-peaked profile emission. We present the preliminary results of testing
the model using data from 11 years of active monitoring of 3C~390.3.


title: Is eta' partially made of gluonium?

abstract:
  A phenomenological analysis of radiative $V\to P\gamma$ and $P\to V\gamma$
decays is performed in order to determine the gluonic content of the
$\eta^\prime$ wave function. Our result shows that there is no evidence for
such a gluonium contribution, $Z_{\eta^\prime}^2=0.04\pm 0.09$. In terms of a
mixing angle description this corresponds to $\phi_P=(41.4\pm 1.3)^\circ$ and
$|\phi_{\eta^\prime G}|=(12\pm 13)^\circ$.


title: Topology from Cosmology

abstract:
  We show that cosmological observables can constrain the topology of the
compact additional dimensions predicted by string theory. To do this, we
develop a general strategy for relating cosmological observables to the
microscopic parameters of the potentials and field-dependent kinetic terms of
the multiple scalar fields that arise in the low-energy limit of string theory.
We apply this formalism to the Large Volume Scenarios in Type IIB flux
compactifications where analytical calculations are possible. Our methods
generalize to other settings.


title: Neutrinos as galactic dark matter in the Ursa Major galaxy group?

abstract:
  We present the analysis of 23 published rotation curves of disk galaxies
belonging to the Ursa Major group of galaxies, with kinematics free of
irregularities. The rotation curves are analysed in the context of MOND
(Modified Newtonian Dynamics). We add an extra component to the rotation curve
fits, in addition to the stellar and gaseous disks: a speculative halo of
constant density made of, e.g., neutrinos, which would solve the bulk of the
problem currently faced by MOND on rich galaxy clusters scales. We find that
this additional unseen mass density is poorly constrained (as expected a
priori, given that a neutrino halo never dominates the kinematics), but we also
find that the best-fit value is non-zero: rho = 3.8 x 10^{-27} g/cm^3, and that
a zero-density is marginally excluded with 87% confidence; also, the 95%
confidence upper limit for the density is rho = 9.6 x 10^{-27} g/cm^3. These
limits are slightly above the expectations from the Tremaine-Gunn phase space
constraints on ordinary 2 eV neutrinos, but in accordance with the maximum
density expected for one or two species of 5 eV sterile neutrinos.


title:
Crystallization of strongly interacting photons in a nonlinear optical
  fiber

abstract:
  Understanding strongly correlated quantum systems is a central problem in
many areas of physics. The collective behavior of interacting particles gives
rise to diverse fundamental phenomena such as confinement in quantum
chromodynamics, phase transitions, and electron fractionalization in the
quantum Hall regime. While such systems typically involve massive particles,
optical photons can also interact with each other in a nonlinear medium. In
practice, however, such interactions are often very weak. Here we describe a
novel technique that allows the creation of a strongly correlated quantum gas
of photons using one-dimensional optical systems with tight field confinement
and coherent photon trapping techniques. The confinement enables the generation
of large, tunable optical nonlinearities via the interaction of photons with a
nearby cold atomic gas. In its extreme, we show that a quantum light field can
undergo fermionization in such one-dimensional media, which can be probed via
standard photon correlation measurements.


title:
Gemini/GMOS Spectroscopy of the Spheroid and Globular Cluster System of
  NGC 3923

abstract:
  We present a technique to extract ultra-deep diffuse-light spectra from the
standard multi-object spectroscopic observations used to investigate
extragalactic globular cluster (GC) systems. This technique allows a clean
extraction of the spectrum of the host galaxy diffuse light from the same
slitlets as the GC targets. We show the utility of the method for investigating
the kinematics and stellar populations of galaxies at radii much greater than
usually probed in longslit studies, at no additional expense in terms of
telescope time. To demonstrate this technique we present Gemini/GMOS
spectroscopy of 29 GCs associated with the elliptical galaxy NGC 3923. We
compare the measured stellar population parameters of the GC system with those
of the spheroid of NGC 3923 at the same projected radii, and find the GCs to
have old ages (> 10 Gyr), [alpha/Fe]~0.3 and a range of metallicities running
from [Z/H] = -1.8 to +0.35. The diffuse light of the galaxy is found to have
ages, metallicities and [alpha/Fe] abundance ratios indistinguishable from
those of the red GCs.


title: The Angular Clustering of Distant Galaxy Clusters

abstract:
  We discuss the angular clustering of galaxy clusters at z > 1 selected within
50 sq. deg from the Spitzer Wide-Infrared Extragalactic survey. We employ a
simple color selection to identify high redshift galaxies with no dependence on
galaxy rest-frame optical color using Spitzer IRAC 3.6 and 4.5 micron
photometry. The majority (>90%) of galaxies with z > 1.3 are identified with
[3.6] - [4.5] > -0.1 AB mag. We identify candidate galaxy clusters at z > 1 by
selecting overdensities of >26-28 objects with [3.6] - [4.5] > -0.1 mag within
radii of 1.4 arcminutes, which corresponds to r < 0.5 Mpc/h at z=1.5. These
candidate galaxy clusters show strong angular clustering, with an angular
correlation function represented by w(theta) = (3.1 +/- 0.5) theta^(-1.1 +/-
0.1) with theta in units of arcminutes over scales of 2-100 arcminutes.
Assuming the redshift distribution of these galaxy clusters follows a fiducial
model, these galaxy clusters have a spatial-clustering scale length r_0 = 22.4
+/- 3.6 Mpc/h, and a comoving number density n = 1.2 +/- 0.1 x 10^-6
(Mpc/h)^-3. The correlation scale length and number density of these objects
are comparable to those of rich galaxy clusters at low redshift. The number
density of these high-redshift clusters correspond to dark-matter halos larger
than 3-5 x 10^13 h^-1 solar masses at z=1.5. Assuming the dark halos hosting
these high-redshift clusters grow following Lambda-CDM models, these clusters
will reside in halos larger than 1-2 x 10^14 h^-1 solar masses at z=0.2,
comparable to rich galaxy clusters.


title: Geometric Precipices in String Cosmology

abstract:
  We consider the effects of graviton multiplet fields on transitions between
string gas phases. Focusing on the dilaton field, we show that it may obstruct
transitions between different thermodynamic phases of the string gas, because
the sign of its dimensionally reduced, $T$-duality invariant, part is conserved
when the energy density of the universe is positive. Thus, many interesting
solutions for which this sign is positive end up in a future curvature
singularity. Because of this, some of the thermodynamic phases of the usual
gravitating string gases behave like superselection sectors. For example, a
past-regular Hagedorn phase and an expanding FRW phase dominated by string
momentum modes cannot be smoothly connected in the framework of string
cosmology with positive sources. The singularity separates them like a
geometric precipice in the moduli space, preventing the dynamics of the theory
from bridging across. Sources which simultaneously violate the positivity of
energy and NEC could modify these conclusions. We provide a quantitative
measure of positivity of energy and NEC violations that would be necessary for
such transitions. These effects must dominate the universe at the moment of
transition, altering the standard gas pictures. At present, it is not known how
to construct such sources from first principles in string theory.


title:
An extreme IMF as an explanation for high M/L ratios in UCDs? The CO
  index as a tracer of bottom heavy IMFs

abstract:
  A new type of compact stellar systems, labelled ``ultra-compact dwarf
galaxies'' (UCDs), was discovered in the last decade. Recent studies show that
their dynamical mass-to-light ratios (M/L) tend to be too high to be explained
by canonical stellar populations, being on average about twice as large as
those of Galactic globular clusters of comparable metallicity. If this offset
is caused by dark matter in UCDs, it would imply dark matter densities as
expected for the centers of cuspy dark matter halos, incompatible with cored
dark matter profiles. Investigating the nature of the high M/L ratios in UCDs
therefore offers important constraints on the phase space properties of dark
matter particles. Here we describe an observational method to test whether a
bottom-heavy IMF may cause the high M/L ratios of UCDs. We propose to use the
CO index at 2.3mu -- which is sensitive to the presence of low-mass stars -- to
test for a bottom heavy IMF. In the case that the high M/L ratios are caused by
a bottom-heavy IMF, we show that the equivalent width of the CO index will be
up to 30% weaker in UCDs compared to sources with similar metallicity that have
canonical IMFs. We find that these effects are well detectable with current
astronomical facilities in a reasonable amount of time (a few hours to nights).
Measuring the CO index of UCDs hence appears a promising tool to investigate
the origin of their high M/L ratios.


title:
Optimized norm-conserving Hartree-Fock pseudopotentials for plane-wave
  calculations

abstract:
  We report Hartree-Fock (HF) based pseudopotentials suitable for plane-wave
calculations. Unlike typical effective core potentials, the present
pseudopotentials are finite at the origin and exhibit rapid convergence in a
plane-wave basis; the optimized pseudopotential method [A. M. Rappe et. al,
Phys. Rev. B 41 1227--30 (1990)] improves plane-wave convergence.
Norm-conserving HF pseudopotentials are found to develop long-range
non-Coulombic behavior which does not decay faster than 1/r, and is non-local.
This behavior, which stems from the nonlocality of the exchange potential, is
remedied using a recently developed self-consistent procedure [J. R. Trail and
R. J. Needs, J. Chem. Phys. 122, 014112 (2005)]. The resulting pseudopotentials
slightly violate the norm conservation of the core charge. We calculated
several atomic properties using these pseudopotentials, and the results are in
good agreement with all-electron HF values. The dissociation energies,
equilibrium bond lengths, and frequency of vibrations of several dimers
obtained with these HF pseudopotentials and plane waves are also in good
agreement with all-electron results.


title:
Valley interference effects on a donor electron close to a Si/SiO2
  interface

abstract:
  We analyze the effects of valley interference on the quantum control and
manipulation of an electron bound to a donor close to a Si/SiO2 interface as a
function of the valley-orbit coupling at the interface. We find that, for
finite valley-orbit coupling, the tunneling times involved in shuttling the
electron between the donor and the interface oscillate with the interface/donor
distance in much the same way as the exchange coupling oscillates with the
interdonor distance. These oscillations disappear when the ground state at the
interface is degenerate (corresponding to zero valley-orbit coupling).


title:
Modelling the Pan-Spectral Energy Distribution of Starburst Galaxies: IV
  The Controlling Parameters of the Starburst SED

abstract:
  We combine the the stellar spectral synthesis code Starburst99, the nebular
modelling code MAPPINGSIII, and a 1-D dynamical evolution model of HII regions
around massive clusters of young stars to generate improved models of the
spectral energy distribution (SED) of starburst galaxies. We introduce a
compactness parameter, C, which characterizes the specific intensity of the
radiation field at ionization fronts in HII regions, and which controls the
shape of the far-IR dust re-emission, often referred to loosely as the dust
``temperature''. We also investigate the effect of metallicity on the overall
SED and in particular, on the strength of the PAH features. We provide
templates for the mean emission produced by the young compact HII regions, the
older (10 - 100 Myr) stars and for the wavelength-dependent attenuation
produced by a foreground screen of the dust used in our model. We demonstrate
that these components may be combined to produce a excellent fit to the
observed SEDs of star formation dominated galaxies which are often used as
templates (Arp 220 and NGC 6240). This fit extends from the Lyman Limit to
wavelengths of about one mm. The methods presented in both this paper and in
the previous papers of this series allow the extraction of the physical
parameters of the starburst region (star formation rates, star formation rate
history, mean cluster mass, metallicity, dust attenuation and pressure) from
the analysis of the pan-spectral SED.


title:
Low Metallicity Indicates that the Hypervelocity Star HE 0437-5439 was
  Ejected from the LMC

abstract:
  We measure the metallicity of the unusual hypervelocity star HE 0437-5439
from high resolution spectroscopy to be half-solar. We determine a spectral
type of B2 IV-III for the star and derive an effective temperature Teff= 21,500
+/- 1,000 K and a surface gravity log(g) = 3.7 +/- 0.2 (cgs). We also present
BV time series photometry and find the star to be non-variable at the 0.02 mag
level. We refine the magnitude of the hypervelocity star to V=16.36+/-0.04 mag,
with a color B-V=-0.23+/-0.03 mag, confirming its early-type nature. Our
metallicity result establishes the origin of HE 0437-5439 in the Large
Magellanic Cloud and implies the existence of a massive black hole somewhere in
this galaxy.


title:
On covariant quantization of M0-brane. Spinor moving frame, pure spinor
  formalism and hidden symmetries of D=11 supergravity

abstract:
  The covariant quantization of massless D=11 superparticle (M0-brane) in its
twistor-like Lorentz harmonic formulation is used to clarify the origin and
some properties of the Berkovits pure spinor approach to quantum superstring
and to search for hidden symmetries of D=11 supergravity. In the twistor like
Lorentz harmonic formulation, the SO(16) symmetry is seen already at the
classical level. The quantization produces the linearized supergravity
multiplet as 128+128=256 component Majorana spinor of SO(16) and also shows an
indirect argument in favor of the possible E8 symmetry.


title: Mass, Metal, and Energy Feedback in Cosmological Simulations

abstract:
  Using Gadget-2 cosmological hydrodynamic simulations including an
observationally-constrained model for galactic outflows, we investigate how
feedback from star formation distributes mass, metals, and energy on cosmic
scales from z=6->0. We include instantaneous enrichment from Type II SNe,
delayed enrichment from Type Ia SNe and stellar (AGB) mass loss, and we
individually track C, O, Si, and Fe. Following on the successes of the
momentum-driven wind scalings, we improve our implementation with an on-the-fly
galaxy finder to derive wind properties based on host galaxy masses. By
tracking wind particles in a suite of simulations, we find: (1) Wind material
reaccretes onto a galaxy on a recycling timescale that varies inversely with
galaxy mass. Hence metals driven into the IGM by galactic superwinds cannot be
assumed to leave their galaxy forever. Wind material is typically recycled
several times; the median number of ejections for a given wind particle is 3,
so by z=0 the total mass ejected in winds exceeds 0.5\Omega_b. (2) The physical
distance winds travel is fairly independent of redshift and galaxy mass (60-100
physical kpc). For sizable galaxies at later epochs, winds typically do not
escape the galaxy halo, and rain back down in a halo fountain. High-z galaxies
enrich a significantly larger comoving volume of the IGM, with metals migrating
back into galaxies to lower z. (3) The energy imparted into winds scales with
M_{gal}^{1/3}, and energy from another source besides SNe (such as photons from
young stars) may be required to distributed cosmic metals as observed. (4) The
production of all 4 metals tracked is globally dominated by Type II SNe at all
epochs. However, intracluster gas iron content triples as a result of non-Type
II sources, and the low-z IGM carbon content is boosted by AGB feedback.


title:
Superfluid-insulator transition in Fermi-Bose mixtures and the
  orthogonality catastrophe

abstract:
  The superfluid-insulator transition of bosons is strongly modified by the
presence of Fermions. Through an imaginary-time path integral approach, we
derive the self-consistent mean-field transition line, and account for both the
static and the dynamic screening effects of the fermions. We find that an
effect akin to the fermionic orthogonality catastrophe, arising from the
fermionic screening fluctuations, suppresses superfluidity. We analyze this
effect for various mixture parameters and temperatures, and consider possible
signatures of the orthogonality catastrophe effect in other measurables of the
mixture.


title: C, N, O Abundances in the Most Metal-Poor Damped Lyman alpha Systems

abstract:
  This study focuses on some of the most metal-poor damped Lyman alpha
absorbers known in the spectra of high redshift QSOs, using new and archival
observations obtained with UV-sensitive echelle spectrographs on the Keck and
VLT telescopes. The weakness and simple velocity structure of the absorption
lines in these systems allows us to measure the abundances of several elements,
and in particular those of C, N, and O, a group that is difficult to study in
DLAs of more typical metallicities. We find that when the oxygen abundance is
less than about 1/100 of solar, the C/O ratio in high redshift DLAs and
sub-DLAs matches that of halo stars of similar metallicity and shows higher
values than expected from galactic chemical evolution models based on
conventional stellar yields. Furthermore, there are indications that at these
low metallicities the N/O ratio may also be above simple expectations and may
exhibit a minimum value, as proposed by Centurion and her collaborators in
2003. Both results can be interpreted as evidence for enhanced production of C
and N by massive stars in the first few episodes of star formation, in our
Galaxy and in the distant proto-galaxies seen as QSO absorbers. The higher
stellar yields implied may have an origin in stellar rotation which promotes
mixing in the stars' interiors, as considered in some recent model
calculations. We briefly discuss the relevance of these results to current
ideas on the origin of metals in the intergalactic medium and the universality
of the stellar initial mass function.


title: Ultra-high energy Neutrinos from Centaurus A and the Auger hot spot

abstract:
  The Pierre Auger collaboration has reported a correlation between Ultra-High
Energy Cosmic Rays (UHECR) and nearby Active Galactic Nuclei (AGNs) within 75
Mpc. Two of these events fall within 3 degrees from Centaurus A, the nearest
AGN, clearly suggesting that this object is a strong UHECR emitter. Here we
pursue this hypothesis and forecast the expected rate of ultra-high energy
neutrinos in detectors like IceCube. In our baseline model we find a rate of
0.4--0.6 yr^-1 events above a threshold of 100 TeV, the uncertainty of which is
mainly related to the poor knowledge of the physical parameters of the source
and on the details of the model. This situation will improve with detailed high
energy gamma ray measurements of Cen A by the upcoming GLAST satellite. This
would make Cen A the first example where the potential of high energy
multi-messenger astronomy is finally realized.


title: Quasar Broad Absorption Line Variability on Multi-Year Time Scales

abstract:
  We use quantitative metrics to characterize the variation of CIV 1549 A broad
absorption lines (BALs) over 3--6 (rest-frame) years in a sample of 13 quasars
at 1.7 <= z <= 2.8 and compare the results to previous studies of BAL
variability on shorter time scales. The strong BALs in our study change in
complex ways over 3--6 yr. Variation occurs in discrete regions which are only
a few thousand km/s wide, and the distribution of the change in absorption
equivalent width broadens over time. We constrain the typical CIV BAL lifetime
to be at least a few decades. While we do not find evidence to support a
scenario in which the variation is primarily driven by photoionization on
multi-year time scales, there is some indication that the variation is produced
by changes in outflow geometry. We do not observe significant changes in the
BAL onset velocity, indicating that the absorber is either far from the source
or is being continually replenished and is azimuthally symmetric.
  It is not possible in a human lifetime to expand the time scales in our study
by more than a factor of a few using optical spectroscopy. However, the strong
variation we have observed in some BALs indicates that future studies of large
numbers of BAL QSOs will be valuable to constrain BAL lifetimes and the physics
of variation.


title: LS I+61 303: microquasar or not microquasar?

abstract:
  LS I +61 303 is a puzzling object detected from radio up to high-energy
gamma-rays. Variability has recently been observed in its high-energy emission.
The object is a binary system, with a compact object and a Be star as primary.
The nature of the secondary and the origin of the gamma-ray emission are not
clearly established at present. Recent VLBA radio data have been used to claim
that the system is a Be/neutron star colliding wind binary, instead of a
microquasar. We review the main views on the nature of LS I +61 303 and present
results of 3D SPH simulations that can shed some light on the nature of the
system. Our results support an accretion powered source, compatible with a
microquasar interpretation.


title: Oceanic Ambient Noise as a Background to Acoustic Neutrino Detection

abstract:
  Ambient noise measured in the deep ocean is studied in the context of a
search for signals from ultra-high energy cosmic ray neutrinos. The spectral
shape of the noise at the relevant high frequencies is found to be very stable
for an extensive data set collected over several months from 49 hydrophones
mounted near the bottom of the ocean at ~1600 m depth. The slopes of the
ambient noise spectra above 15 kHz are found to roll-off faster than the -6
dB/octave seen in Knudsen spectra. A model attributing the source to an uniform
distribution of surface noise that includes frequency-dependent absorption at
large depth is found to fit the data well up to 25 kHz. This depth dependent
model should therefore be used in analysis methods of acoustic neutrino pulse
detection that require the expected noise spectra.


title:
Scattering for H^1/2 bounded solutions to the cubic, defocusing NLS in 3
  dimensions

abstract:
  We show that if a solution of the defocusing cubic NLS in 3d remains bounded
in the homogeneous Sobolev norm of order 1/2 in its maximal interval of
existence, then the interval is infinite and the solution scatters. No radial
assumption is made.


title:
Invertible Mappings of Nonlinear PDEs to Linear PDEs Through Admitted
  Conservation Laws

abstract:
  An algorithmic method using conservation law multipliers is introduced that
yields necessary and sufficient conditions to find invertible mappings of a
given nonlinear PDE to some linear PDE and to construct such a mapping when it
exists. Previous methods yielded such conditions from admitted point or contact
symmetries of the nonlinear PDE. Through examples, these two linearization
approaches are contrasted.


title: Percolation in quantum computation and communication

abstract:
  This article is a draft of a book chapter of the book entitled "Quantum
Percolation and Breakdown", to appear 2008.


title: Approximated profiles for discrete solitons in DNLS lattices

abstract:
  We study four different approximations for finding the profile of discrete
solitons in the one-dimensional Discrete Nonlinear Schr\"odinger (DNLS)
Equation. Three of them are discrete approximations (namely, a variational
approach, an approximation to homoclinic orbits and a Green-function approach),
and the other one is a quasi-continuum approximation. All the results are
compared with numerical computations.


title: Resonance production in heavy-ion collisions at STAR

abstract:
  Hadronic resonances are sensitive to the properties of a hot and dense medium
created in a heavy ion collisions. During the hadronic phase, after
hadronization of quark and gluons into hadrons, resonances are useful to
determine the lifetime between chemical and thermal freeze-out, under the
assumption that the re-scattering of the decay particles and the probability of
regeneration of resonances from hadrons depends on the system properties and
the resonance lifetime. The system size and energy dependence of resonance
spectra and yields will be shown and discussed in the context of the lifetime
and size of the hadronic phase. Elliptic flow measurement will extend the
sensitivity of resonance yields to the partonic state through additional
information on constituent quark scaling. We also explore a possible new
technique to extract signals from the early, potentially chirally symmetric,
stage through the selection of resonances from jets.


title: Energy of eigen-modes in magnetohydrodynamic flows of ideal fluids

abstract:
  Analytical expression for energy of eigen-modes in magnetohydrodynamic flows
of ideal fluids is obtained. It is shown that the energy of unstable modes is
zero, while the energy of stable oscillatory modes (waves) can assume both
positive and negative values. Negative energy waves always correspond to
non-symmetric eigen-modes -- modes that have a component of wave-vector along
the equilibrium velocity. These results suggest that all non-symmetric
instabilities in ideal MHD systems with flows are associated with coupling of
positive and negative energy waves. As an example the energy of eigen-modes is
calculated for incompressible conducting fluid rotating in axial magnetic
field.


title: Geometry of Shimura varieties of Hodge type over finite fields

abstract:
  We present a general and comprehensive overview of recent developments in the
theory of integral models of Shimura varieties of Hodge type. The paper covers
the following topics: construction of integral models, their possible moduli
interpretations, their uniqueness, their smoothness, their properness, and
basic stratifications of their special fibres.


title:
A three stage model for the inner engine of GRBs: Prompt emission and
  early afterglow

abstract:
  We describe a model within the ``Quark-nova'' scenario to interpret the
recent observations of early X-ray afterglows of long Gamma-Ray Bursts (GRB)
with the Swift satellite. This is a three-stage model within the context of a
core-collapse supernova. STAGE 1 is an accreting (proto-) neutron star leading
to a possible delay between the core collapse and the GRB. STAGE 2 is accretion
onto a quark-star, launching an ultrarelativistic jet generating the prompt
GRB. This jet also creates the afterglow as the jet interacts with the
surrounding medium creating an external shock. Slower shells ejected from the
quark star (during accretion), can re-energize the external shock leading to a
flatter segment in the X-ray afterglow. STAGE 3, which occurs only if the
quark-star collapses to form a black-hole, consists of an accreting black-hole.
The jet launched in this accretion process interacts with the preceding quark
star jet, and could generate the flaring activity frequently seen in early
X-ray afterglows. Alternatively, a STAGE 2b can occur in our model if the quark
star does not collapse to a black hole. The quark star in this case can then
spin down due to magnetic braking, and the spin down energy may lead to
flattening in the X-ray afterglow as well. This model seems to account for both
the energies and the timescales of GRBs, in addition to the newly discovered
early X-ray afterglow features.


title: A Note on Kasparov Product and Duality

abstract:
  Using Paschke-Higson duality, we can get a natural index pairing $K_{i}(A)
\times K_{i+1}(D_{\Phi}) \to \boldsymbol{Z} \quad (i=0,1) (\mbox{mod}2)$, where
$A$ is a separable $C\sp*$-algebra, and $\Phi$ is a representation of $A$ on a
separable infinite dimensional Hilbert space $H$. It is proved that this is a
special case of the Kasparov Product. As a step, we show a proof of
Bott-periodicity for KK-theory asserting that $\mathbb{C}_1$ and $S$ are
$KK$-equivalent using the odd index pairing.


title: Betti Numbers of Graded Modules and Cohomology of Vector Bundles

abstract:
  Mats Boij and Jonas Soederberg (math.AC/0611081) have conjectured that the
Betti table of a Cohen-Macaulay module over a polynomial ring can be decomposed
in a certain way as a positive linear combination of Betti tables of modules
with pure resolutions. We prove, over any field, a strengthened form of their
conjecture. Applications include a proof of the Multiplicity Conjecture of
Huneke and Srinivasan and a proof of the convexity of a fan naturally
associated to the Young lattice.
  We also characterize the rational cone of all cohomology tables of vector
bundles on projective spaces in terms of the cohomology tables of
"supernatural" bundles. This characterization is dual, in a certain sense, to
our characterization of Betti tables.


title:
Fractional Optimal Control in the Sense of Caputo and the Fractional
  Noether's Theorem

abstract:
  The study of fractional variational problems with derivatives in the sense of
Caputo is a recent subject, the main results being Agrawal's necessary
optimality conditions of Euler-Lagrange and respective transversality
conditions. Using Agrawal's Euler-Lagrange equation and the Lagrange multiplier
technique, we obtain here a Noether-like theorem for fractional optimal control
problems in the sense of Caputo.


title: Automated identification of neurons and their locations

abstract:
  Individual locations of many neuronal cell bodies (>10^4) are needed to
enable statistically significant measurements of spatial organization within
the brain such as nearest-neighbor and microcolumnarity measurements. In this
paper, we introduce an Automated Neuron Recognition Algorithm (ANRA) which
obtains the (x,y) location of individual neurons within digitized images of
Nissl-stained, 30 micron thick, frozen sections of the cerebral cortex of the
Rhesus monkey. Identification of neurons within such Nissl-stained sections is
inherently difficult due to the variability in neuron staining, the overlap of
neurons, the presence of partial or damaged neurons at tissue surfaces, and the
presence of non-neuron objects, such as glial cells, blood vessels, and random
artifacts. To overcome these challenges and identify neurons, ANRA applies a
combination of image segmentation and machine learning. The steps involve
active contour segmentation to find outlines of potential neuron cell bodies
followed by artificial neural network training using the segmentation
properties (size, optical density, gyration, etc.) to distinguish between
neuron and non-neuron segmentations. ANRA positively identifies 86[5]% neurons
with 15[8]% error (mean[st.dev.]) on a wide range of Nissl-stained images,
whereas semi-automatic methods obtain 80[7]%/17[12]%. A further advantage of
ANRA is that it affords an unlimited increase in speed from semi-automatic
methods, and is computationally efficient, with the ability to recognize ~100
neurons per minute using a standard personal computer. ANRA is amenable to
analysis of huge photo-montages of Nissl-stained tissue, thereby opening the
door to fast, efficient and quantitative analysis of vast stores of archival
material that exist in laboratories and research collections around the world.


title: Lattice instabilities in cubic pyrochlore Bi$_2$Ti$_2$O$_7$

abstract:
  The oxide pyrochlore Bi$_2$Ti$_2$O$_7$ is in some ways analogous to
perovskite PbTiO$_3$, in that Bi$_2$Ti$_2$O$_7$ has two cations, Bi$^{3+}$ and
Ti$^{4+}$ in oxidation states that are normally associated with a propensity to
off-center. However, unlike PbTiO$_3$, Bi$_2$Ti$_2$O$_7$ is experimentally
observed to remain cubic down to 2 K, while the only observed ionic
displacements are local and incoherent. Here we report first-principles
calculations of the zone-center phonons of the ordered cubic pyrochlore which
reveal several lattice instabilities. An analysis of the structural energetics
suggest that the ordered cubic pyrochlore is unstable with respect to
distortion towards a ferroelectric ground state with a large polarization. Our
results suggest a key role of a frustrated soft polar mode in the dielectric
properties of bismuth pyrochlores.


title: Superconductivity in Sr2RuO4-Sr3Ru2O7 eutectic crystals

abstract:
  Superconducting behavior has been observed in the Sr2RuO4-Sr3Ru2O7 eutectic
system as grown by the flux-feeding floating zone technique. A supercurrent
flows across a single interface between Sr2RuO4 and Sr3Ru2O7 areas at distances
that are far beyond those expected in a conventional proximity scenario. The
current-voltage characteristics within the Sr3Ru2O7 macrodomain, as extracted
from the eutectic, exhibit signatures of superconductivity in the bilayered
ruthenate. Detailed microstructural, morphological and compositional analyses
address issues on the concentration and the size of Sr2RuO4 inclusions within
the Sr3Ru2O7 matrix. We speculate on the possibility of inhomogeneous
superconductivity in the eutectic Sr3Ru2O7 and exotic pairing induced by the
Sr2RuO4 inclusions.


title:
Asymptotics of Plancherel measures for the infinite-dimensional unitary
  group

abstract:
  We study a two-dimensional family of probability measures on infinite
Gelfand-Tsetlin schemes induced by a distinguished family of extreme characters
of the infinite-dimensional unitary group. These measures are unitary group
analogs of the well-known Plancherel measures for symmetric groups. We show
that any measure from our family defines a determinantal point process, and we
prove that in appropriate scaling limits, such processes converge to two
different extensions of the discrete sine process as well as to the extended
Airy and Pearcey processes.


title: Weak nuclear forces cause the strong nuclear force

abstract:
  We determine the strength of the weak nuclear force which holds the lattices
of the elementary particles together. We also determine the strength of the
strong nuclear force which emanates from the sides of the nuclear lattices. The
strong force is the sum of the unsaturated weak forces at the surface of the
nuclear lattices. The strong force is then about ten to the power of 6 times
stronger than the weak force between two lattice points.


title: Holographic Calculation of Boundary Entropy

abstract:
  We use the holographic proposal for calculating entanglement entropies to
determine the boundary entropy of defects in strongly coupled two-dimensional
conformal field theories. We study several examples including the Janus
solution and show that the boundary entropy extracted from the entanglement
entropy as well as its more conventional definition via the free energy agree
with each other. Maybe somewhat surprisingly we find that, unlike in the case
of a conformal field theory with boundary, the entanglement entropy for a
generic region in a theory with defect carries detailed information about the
microscopic details of the theory. We also argue that the g-theorem for the
boundary entropy is closely related to the strong subadditivity of the
entanglement entropy.


title: Scalar one-loop integrals for QCD

abstract:
  We construct a basis set of infra-red and/or collinearly divergent scalar
one-loop integrals and give analytic formulas, for tadpole, bubble, triangle
and box integrals, regulating the divergences (ultra-violet, infra-red or
collinear) by regularization in $D=4-2\epsilon$ dimensions. For scalar triangle
integrals we give results for our basis set containing 6 divergent integrals.
For scalar box integrals we give results for our basis set containing 16
divergent integrals. We provide analytic results for the 5 divergent box
integrals in the basis set which are missing in the literature. Building on the
work of van Oldenborgh, a general, publicly available code has been
constructed, which calculates both finite and divergent one-loop integrals. The
code returns the coefficients of $1/\epsilon^2,1/\epsilon^1$ and $1/\epsilon^0$
as complex numbers for an arbitrary tadpole, bubble, triangle or box integral.


title: Diffusion, dimensionality and noise in transcriptional regulation

abstract:
  The precision of biochemical signaling is limited by randomness in the
diffusive arrival of molecules at their targets. For proteins binding to the
specific sites on the DNA and regulating transcription, the ability of the
proteins to diffuse in one dimension by sliding along the length of the DNA, in
addition to their diffusion in bulk solution, would seem to generate a larger
target for DNA binding, consequently reducing the noise in the occupancy of the
regulatory site. Here we show that this effect is largely cancelled by the
enhanced temporal correlations in one dimensional diffusion. With realistic
parameters, sliding along DNA has surprisingly little effect on the physical
limits to the precision of transcriptional regulation.


title:
Time-resolved Observation and Control of Superexchange Interactions with
  Ultracold Atoms in Optical Lattices

abstract:
  Quantum mechanical superexchange interactions form the basis of quantum
magnetism in strongly correlated electronic media. We report on the direct
measurement of superexchange interactions with ultracold atoms in optical
lattices. After preparing a spin-mixture of ultracold atoms in an
antiferromagnetically ordered state, we measure a coherent
superexchange-mediated spin dynamics with coupling energies from 5 Hz up to 1
kHz. By dynamically modifying the potential bias between neighboring lattice
sites, the magnitude and sign of the superexchange interaction can be
controlled, thus allowing the system to be switched between antiferromagnetic
or ferromagnetic spin interactions. We compare our findings to predictions of a
two-site Bose-Hubbard model and find very good agreement, but are also able to
identify corrections which can be explained by the inclusion of direct
nearest-neighbor interactions.


title:
Back-of-the-Envelope Computation of Throughput Distributions in CSMA
  Wireless Networks

abstract:
  This work started out with our accidental discovery of a pattern of
throughput distributions among links in IEEE 802.11 networks from experimental
results. This pattern gives rise to an easy computation method, which we term
back-of-the-envelop (BoE) computation, because for many network configurations,
very accurate results can be obtained within minutes, if not seconds, by simple
hand computation. BoE beats prior methods in terms of both speed and accuracy.
While the computation procedure of BoE is simple, explaining why it works is by
no means trivial. Indeed the majority of our investigative efforts have been
devoted to the construction of a theory to explain BoE. This paper models an
ideal CSMA network as a set of interacting on-off telegraph processes. In
developing the theory, we discovered a number of analytical techniques and
observations that have eluded prior research, such as that the carrier-sensing
interactions among links in an ideal CSMA network result in a system state
evolution that is time-reversible; and that the probability distribution of the
system state is insensitive to the distributions of the "on" and "off"
durations given their means, and is a Markov random field. We believe these
theoretical frameworks are useful not just for explaining BoE, but could also
be a foundation for a fundamental understanding of how links in CSMA networks
interact. Last but not least, because of their basic nature, we surmise that
some of the techniques and results developed in this paper may be applicable to
not just CSMA networks, but also to other physical and engineering systems
consisting of entities interacting with each other in time and space.


title:
A variation of multiple $L$-values arising from the spectral zeta
  function of the non-commutative harmonic oscillator

abstract:
  A variation of multiple $L$-values, which arises from the description of the
special values of the spectral zeta function of the non-commutative harmonic
oscillator, is introduced. In some special cases, we show that its generating
function can be written in terms of the gamma functions. This result enables us
to obtain explicit evaluations of them.


title: Tunneling phase gate for neutral atoms in a double-well lattice

abstract:
  We propose a new two--qubit phase gate for ultra--cold atoms confined in an
experimentally realized tilted double--well optical lattice [Sebby--Strabley et
al., Phys. Rev. A {\bf 73} 033605 (2006)]. Such a lattice is capable of
confining pairs of atoms in a two--dimensional array of double--well potentials
where control can be exercised over the barrier height and the energy
difference of the minima of the two wells (known as the ``tilt''). The four
lowest single--particle motional states consist of two pairs of motional states
in which each pair is localized on one side of the central barrier, allowing
for two atoms confined in such a lattice to be spatially separated qubits. We
present a time--dependent scheme to manipulate the tilt to induce tunneling
oscillations which produce a collisional phase gate. Numerical simulations
demonstrate that this gate can be performed with high fidelity.


title:
On Black Hole Mass Estimation from X-ray Spectra of Ultraluminous X-ray
  Sources

abstract:
  We propose a methodology to derive a black-hole mass for super-critical
accretion flow. Here, we use the extended disk blackbody (extended DBB) model,
a fitting model in which the effective temperature profile obeys the relation
$T_{\rm eff} \propto r^{-p}$, with $r$ being the disk radius and $p$ being
treated as a fitting parameter. We first numerically calculate the theoretical
flow structure and its spectra for a given black-hole mass, $M$, and accretion
rate, $\dot{M}$. Through fitting to the theoretical spectra by the extended DBB
model, we can estimate the black-hole mass, $M_{\rm x}$, assuming that the
innermost disk radius is $r_{\rm in}=3r_{\rm g} (\propto M_{\rm x})$, where
$r_{\rm g}$ is the Schwarzschild radius. We find, however, that the estimated
mass deviates from that adopted in the spectral calculations, $M$, even for
low-$\dot{M}$ cases. We also find that the deviations can be eliminated by
introducing a new correction for the innermost radius. Using this correction,
we calculate mass correction factors, $M/M_{\rm x}$, in the super-critical
regimes for some sets of $M$ and $\dot M$, finding that a mass correction
factor ranges between $M/M_{\rm x} \sim$ 1.2 -- 1.6. The higher is $\dot{M}$,
the larger does the mass correction factor tend to be. Since the correction is
relatively small, we can safely conclude that the black holes in ULXs which
Vierdayanti et al. (2006, PASJ, 58, 915) analyzed are stellar-mass black holes
with the mass being $< 100M_{\odot}$.


title: Comet 9P/Tempel 1: Interpretation with the Deep Impact Results

abstract:
  According to our common understandings, the original surface of a
short-period comet nucleus has been lost by sublimation processes during its
close approaches to the Sun. Sublimation results in the formation of a dust
mantle on the retreated surface and in chemical differentiation of ices over
tens or hundreds of meters below the mantle. In the course of NASA's Deep
Impact mission, optical and infrared imaging observations of the ejecta plume
were conducted by several researchers, but their interpretations of the data
came as a big surprise: (1) The nucleus of comet 9P/Tempel 1 is free of a dust
mantle, but maintains its pristine crust of submicron-sized carbonaceous
grains; (2) Primordial materials are accessible already at a depth of several
tens of cm with abundant silicate grains of submicrometer sizes. In this study,
we demonstrate that a standard model of cometary nuclei explains well available
observational data: (1) A dust mantle with a thickness of ~1-2 m builds up on
the surface, where compact aggregates larger than tens of micrometers dominate;
(2) Large fluffy aggregates are embedded in chemically differentiated layers as
well as in the deepest part of the nucleus with primordial materials. We
conclude that the Deep Impact results do not need any peculiar view of a comet
nucleus.


title:
Fitting Formulae for the Effects of Binary Interactions on Lick Indices
  and Colours of Stellar Populations

abstract:
  More than about 50% stars of galaxies are in binaries, but most stellar
population studies take single star-stellar population (ss-SSP) models, which
do not take binary interactions into account. In fact, the integrated
peculiarities of ss-SSPs are various from those of stellar populations with
binary interactions (bs-SSPs). Therefore, it is necessary to investigate the
effects of binary interactions on the Lick indices and colours of populations
detailedly. We show some formulae for calculating the difference between the
Lick indices and colours of bs-SSPs, and those of ss-SSPs. Twenty-five Lick
indices and 12 colours are studied in the work. The results can be conveniently
used for estimating the effects of binary interactions on stellar population
studies and for adding the effects of binary interactions into existing ss-SSP
models. The results and a few procedures can be obtained on request to the
authors or via http://www.ynao.ac.cn/~bps/zhongmu/download.htm


title:
Integrability, stability, and adiabaticity in nonlinear stimulated Raman
  adiabatic passage

abstract:
  We study dynamics of a two-color photoassociation of atoms into diatomic
molecules via nonlinear Stimulated Raman adiabatic passage (STIRAP) process.
This system has a famous counterpart in (linear) quantum mechanics, and been
discussed recently in the context of generalizing quantum adiabatic theorem to
nonlinear systems. Here we use another approach to study adiabaticity and
stability in the system: we apply methods of classical Hamiltonian dynamics. We
found nonlinear dynamical instabilities, cases of complete integrability, and
improved conditions of adiabaticity.


title: CKM Phase and Spontaneous CP Violation

abstract:
  The Standard Model for CP violation, the CKM model, works very well in
explaining all laboratory experimental data. However, this model does not
address the question that where it comes from. The origin of CP violation is
still a mystery. In this talk I discuss a model\cite{model} addressing this
problem in which the CP violating phase in the CKM matrix is identical to the
phase in the Higgs potential resulting from spontaneous CP violation.


title:
Spin states of zigzag-edged Mobius graphene nanoribbons from first
  principles

abstract:
  Mobius graphene nanoribbons have only one edge topologically. How the
magnetic structures, previously associated with the two edges of zigzag-edged
flat nanoribbons or cyclic nanorings, would change for their Mobius
counterparts is an intriguing question. Using spin-polarized density functional
theory, we shed light on this question. We examine spin states of zigzag-edged
Mobius graphene nanoribbons (ZMGNRs) with different widths and lengths. We find
a triplet ground state for a Mobius cyclacene, while the corresponding
two-edged cyclacene has an open-shell singlet ground state. For wider ZMGNRs,
the total magnetization of the ground state is found to increase with the
ribbon length. For example, a quintet ground state is found for a ZMGNR. Local
magnetic moments on the edge carbon atoms form domains of majority and minor
spins along the edge. Spins at the domain boundaries are found to be
frustrated. Our findings show that the Mobius topology (i.e., only one edge)
causes ZMGNRs to favor one spin over the other, leading to a ground state with
non-zero total magnetization.


title: Constructing Bio-molecular Databases on a DNA-based Computer

abstract:
  Codd [Codd 1970] wrote the first paper in which the model of a relational
database was proposed. Adleman [Adleman 1994] wrote the first paper in which
DNA strands in a test tube were used to solve an instance of the Hamiltonian
path problem. From [Adleman 1994], it is obviously indicated that for storing
information in molecules of DNA allows for an information density of
approximately 1 bit per cubic nm (nanometer) and a dramatic improvement over
existing storage media such as video tape which store information at a density
of approximately 1 bit per 1012 cubic nanometers. This paper demonstrates that
biological operations can be applied to construct bio-molecular databases where
data records in relational tables are encoded as DNA strands. In order to
achieve the goal, DNA algorithms are proposed to perform eight operations of
relational algebra (calculus) on bio-molecular relational databases, which
include Cartesian product, union, set difference, selection, projection,
intersection, join and division. Furthermore, this work presents clear evidence
of the ability of molecular computing to perform data retrieval operations on
bio-molecular relational databases.


title: On endomorphism algebras of separable monoidal functors

abstract:
  We show that the (co)endomorphism algebra of a sufficiently separable "fibre"
functor into Vect_k, for k a field of characteristic 0, has the structure of
what we call a "unital" von Neumann core in Vect_k. For Vect_k, this particular
notion of algebra is weaker than that of a Hopf algebra, although the
corresponding concept in Set is again that of a group.


title: Coplanar k-unduloids are nondegenerate

abstract:
  We prove each embedded, constant mean curvature (CMC) surface in Euclidean
space with genus zero and finitely many coplanar ends is nondegenerate: there
is no nontrivial square-integrable solution to the Jacobi equation, the
linearization of the CMC condition. This implies that the moduli space of such
coplanar surfaces is a real-analytic manifold and that a neighborhood of these
in the full CMC moduli space is itself a manifold. Nondegeneracy further
implies (infinitesimal and local) rigidity in the sense that the asymptotes map
is an analytic immersion on these spaces, and also that the coplanar
classifying map is an analytic diffeomorphism.


title: Chemical Evolution in VeLLOs

abstract:
  A new type of object called "Very Low Luminosity Objects (VeLLOs)" has been
discovered by the Spitzer Space Telescope. VeLLOs might be substellar objects
forming by accretion. However, some VeLLOs are associated with strong outflows,
indicating the previous existence of massive accretion. The thermal history,
which significantly affects the chemistry, between substellar objects with a
continuous low accretion rate and objects in a quiescent phase after massive
accretion (outburst) must be greatly different. In this study, the chemical
evolution has been calculated in an episodic accretion model to show that CO
and N2H+ have a relation different from starless cores or Class 0/I objects.
Furthermore, the CO2 ice feature at 15.2 micron will be a good tracer of the
thermal process in VeLLOs.


title: Poisson Matching

abstract:
  Suppose that red and blue points occur as independent homogeneous Poisson
processes in R^d. We investigate translation-invariant schemes for perfectly
matching the red points to the blue points. For any such scheme in dimensions
d=1,2, the matching distance X from a typical point to its partner must have
infinite d/2-th moment, while in dimensions d>=3 there exist schemes where X
has finite exponential moments. The Gale-Shapley stable marriage is one natural
matching scheme, obtained by iteratively matching mutually closest pairs. A
principal result of this paper is a power law upper bound on the matching
distance X for this scheme. A power law lower bound holds also. In particular,
stable marriage is close to optimal (in tail behavior) in d=1, but far from
optimal in d>=3. For the problem of matching Poisson points of a single color
to each other, in d=1 there exist schemes where X has finite exponential
moments, but if we insist that the matching is a deterministic factor of the
point process then X must have infinite mean.


title:
Parameterization studies of the properties of the X-ray dips for Low
  Mass X-ray binary X1916-053

abstract:
  The ultra-compact Low Mass X-ray Binary (LMXB) X1916-053, composed of a
neutron star and a semi-degenerated white dwarf, exhibits periodic X-ray dips
with variable width and depth. We have developed new methods to parameterize
the dip to systematically study its variations. This helps to further
understand binary and accretion disk behaviors. The RXTE 1998 observations
clearly show a 4.87d periodic variation of the dip width. This is probably due
to the nodal precession of the accretion disk, although there are no
significant sidebands in the spectrum from the epoch folding search. From the
negative superhump model (Larwood et. al. 1996), the mass ratio can be
estimated as q = 0.045. Combined with more than 24 years of historical data, we
found an orbital period derivative of $\dot{P}_{orb}/P_{orb}=(1.62 \pm
0.48)\times 10^{-7} yr^{-1}$ and established a quadratic ephemeris for the
X-ray dips. The period derivative seems inconsistent with the prediction of the
standard model of binary orbital evolution proposed by Rappaport et. al.
(1987). On the other hand, the radiation-driven model (Tavani et. al. 1991) may
properly interpret the period derivative even though the large mass outflow
predicted by this model has never been observed in this system. With the best
ephemeris, we obtained that the standard deviation of primary dips are smaller
than that of secondary dips. This means that the primary dips are more stable
than the secondary dips. Thus, we conclude that the primary dips of X1916-053
occur from the bulge at the rim instead of the ring of the disk proposed by
Frank et. al. (1987).


title: Two-connected graphs with prescribed three-connected components

abstract:
  We adapt the classical 3-decomposition of any 2-connected graph to the case
of simple graphs (no loops or multiple edges). By analogy with the
block-cutpoint tree of a connected graph, we deduce from this decomposition a
bicolored tree tc(g) associated with any 2-connected graph g, whose white
vertices are the 3-components of g (3-connected components or polygons) and
whose black vertices are bonds linking together these 3-components, arising
from separating pairs of vertices of g. Two fundamental relationships on graphs
and networks follow from this construction. The first one is a dissymmetry
theorem which leads to the expression of the class B=B(F) of 2-connected
graphs, all of whose 3-connected components belong to a given class F of
3-connected graphs, in terms of various rootings of B. The second one is a
functional equation which characterizes the corresponding class R=R(F) of
two-pole networks all of whose 3-connected components are in F. All the
rootings of B are then expressed in terms of F and R. There follow
corresponding identities for all the associated series, in particular the edge
index series. Numerous enumerative consequences are discussed.


title: Duality Theorem and Hom Functor in Braided Tensor Categories

abstract:
  Blatter-Montgomery duality theorem is generalized into braided tensor
categories. It is shown that $Hom(V,W)$ is a braided Yetter-Drinfeld module for
any two braided Yetter-Drinfeld modules $V$ and $W$.


title: Were All Massive Stars Born in OB Associations and Clusters?

abstract:
  It has been commonly conjectured that all massive >10 Msun stars are born in
OB associations or clusters. Many O and B stars in the Galaxy or the Magellanic
Clouds appear to exist in isolation, however. While some of these field OB
stars have been ejected from their birthplaces, some are too far away from
massive star forming regions to be runaways. Can massive stars form in
isolation? The Spitzer survey of the Large Magellanic Cloud (aka SAGE) provides
a unique opportunity for us to investigate and characterize the formation sites
of massive stars for an entire galaxy. We have identified all massive young
stellar objects (YSOs) in the Large Magellanic Cloud. We find that ~85% of the
massive YSOs are in giant molecular clouds and ~65% are in OB associations.
Only ~7% of the massive YSOs are neither in OB associations nor in giant
molecular clouds. This fraction of isolated massive stars in the Large
Magellanic Cloud is comparable to the 5-10% found in the Galaxy.


title:
Supercritical general branching processes conditioned on extinction are
  subcritical

abstract:
  It is well known that a simple, supercritical Bienaym\'e-Galton-Watson
process turns into a subcritical such process, if conditioned to die out. We
prove that the corresponding holds true for general, multi-type branching,
where child-bearing may occur at different ages, life span may depend upon
reproduction, and the whole course of events is thus affected by conditioning
upon extinction.


title: Shape invariance method for quintom model in the bent brane background

abstract:
  In the present paper, we study the braneworld scenarios in the presence of
quintom dark energy coupled by gravity. The first-order formalism for the bent
brane (for both de Sitter and anti-de Sitter geometry), leads us to discuss the
shape invariance method in the bent brane systems. So, by using the
fluctuations of metric and quintom fields we obtain the Schrodinger equation.
Then we factorize the corresponding Hamiltonian in terms of multiplication of
the first-order differential operators. These first-order operators lead us to
obtain the energy spectrum with the help of shape invariance method.


title: On localizing subcategories of derived categories

abstract:
  Let A be a commutative noetherian ring. In this paper, we interpret
localizing subcategories of the derived category of A by using subsets of Spec
A and subcategories of the category of A-modules. We unify theorems of Gabriel,
Neeman and Krause.


title:
Critique du rapport signal \`a bruit en th\'eorie de l'information -- A
  critical appraisal of the signal to noise ratio in information theory

abstract:
  The signal to noise ratio, which plays such an important role in information
theory, is shown to become pointless in digital communications where - symbols
are modulating carriers, which are solutions of linear differential equations
with polynomial coefficients, - demodulations is achieved thanks to new
algebraic estimation techniques. Operational calculus, differential algebra and
nonstandard analysis are the main mathematical tools.

categories: cs.IT math.IT math.LO math.PR math.RA quant-ph


title: SLOCC classification for nine families of four-qubits

abstract:
  In Phys. Rev. A 62, 062314 (2000), D\"{u}r, Vidal and Cirac indicated that
there are infinitely many SLOCC classes for four qubits. Verstraete, Dehaene,
and Verschelde in Phys. Rev. A 65, 052112 (2002) proposed nine families of
states corresponding to nine different ways of entangling four qubits. In Phys.
Rev. A 75, 022318 (2007), Lamata et al. reported that there are eight true
SLOCC entanglement classes of four qubits up to permutations of the qubits. In
this paper, we investigate SLOCC classification of the nine families proposed
by Verstraete, Dehaene and Verschelde, and distinguish 49 true SLOCC
entanglement classes from them.


title: Trigonometry in extended hyperbolic space and extended de Sitter space

abstract:
  We study the hyperbolic cosine and sine laws in the extended hyperbolic space
which contains hyperbolic space as a subset and is an analytic continuation of
the hyperbolic space. And we also study the spherical cosine and sine laws in
the extended de Sitter space which contains de Sitter Space $S^n_1$ as a subset
and is also an analytic continuation of de Sitter space. In fact, the extended
hyperbolic space and extended de Sitter space are the same space only differ by
-1 multiple in the metric. Hence these two extended spaces clearly show and
apparently explain that why many corresponding formulas in hyperbolic and
spherical space are very similar each other. From these extended trigonometry
laws, we can give a coherent and geometrically simple explanation for the
various relations between the lengths and angles of hyperbolic polygons and
relations on de Sitter polygons which lie on $S^2_1$.


title: Hierarchy construction schemes within the Scale set framework

abstract:
  Segmentation algorithms based on an energy minimisation framework often
depend on a scale parameter which balances a fit to data and a regularising
term. Irregular pyramids are defined as a stack of graphs successively reduced.
Within this framework, the scale is often defined implicitly as the height in
the pyramid. However, each level of an irregular pyramid can not usually be
readily associated to the global optimum of an energy or a global criterion on
the base level graph. This last drawback is addressed by the scale set
framework designed by Guigues. The methods designed by this author allow to
build a hierarchy and to design cuts within this hierarchy which globally
minimise an energy. This paper studies the influence of the construction scheme
of the initial hierarchy on the resulting optimal cuts. We propose one
sequential and one parallel method with two variations within both. Our
sequential methods provide partitions near the global optima while parallel
methods require less execution times than the sequential method of Guigues even
on sequential machines.


title: Ultrafast Electron-Phonon Decoupling in Graphite

abstract:
  We report the ultrafast dynamics of the 47.4 THz coherent phonons of graphite
interacting with a photoinduced non-equilibrium electron-hole plasma. Unlike
conventional materials, upon photoexcitation the phonon frequency of graphite
upshifts, and within a few picoseconds relaxes to the stationary value. Our
first-principles density functional calculations demonstrate that the phonon
stiffening stems from the light-induced decoupling of the non-adiabatic
electron-phonon interaction by creating the non-equilibrium electron-hole
plasma. Time-resolved vibrational spectroscopy provides a window on the
ultrafast non-equilibrium electron dynamics.


title: Normal Forms, K3 Surface Moduli, and Modular Parametrizations

abstract:
  The geometric objects of study in this paper are K3 surfaces which admit a
polarization by the unique even unimodular lattice of signature (1,17). A
standard Hodge-theoretic observation about this special class of K3 surfaces is
that their polarized Hodge structures are identical with the polarized Hodge
structures of abelian surfaces that are cartesian products of elliptic curves.
Earlier work of the first two authors gives an explicit normal form and
construction of the moduli space for these surfaces. In the present work, this
normal form is used to derive Picard-Fuchs differential equations satisfied by
periods of these surfaces. We also investigate the subloci of the moduli space
on which the polarization is enhanced. In these cases, we derive information
about the Picard-Fuchs differential equations satisfied by periods of these
subfamilies, and we relate this information to the theory of genus zero
quotients of the upper half-plane by Moonshine groups. For comparison, we also
examine the analogous theory for elliptic curves in Weierstrass form.


title:
Conformal transformation in the scalar-tensor theory applied to the
  accelerating universe

abstract:
  The scalar-tensor theory is plagued by nagging questions if different
conformal frames, in particular the Jordan and Einstein conformal frames, are
equivalent to each other. As a closely related question, there are opposing
views on which of the two conformal frames is physically acceptable.
Reinforcing our previous claims, we offer replies based on a cosmological model
of the scalar-tensor theory, believed to be a promising theory for
understanding the accelerating universe, as well as today's version of the
cosmological constant problem. Exploiting the advantage that this model admits
analytical asymptotic solutions, our argument does not depend on whether the
underlying theory is invariant under conformal transformations. Our argument
provides partial support for the claimed "equivalence," but we also present
examples that require more careful analyses exploiting field equations. We also
point out that the Jordan conformal frame is suitable for an interpretation in
terms of unification theories in physics, for example, string theory and the
Kaluza-Klein approach, while the Einstein conformal frame may be acceptable as
a physical conformal frame under two conditions: (i) the simplest constant
$\Lambda$ term in the Lagrangian in the Jordan conformal frame; (ii) the
revised form of the conventional Brans-Dicke model based on the validity of
weak equivalence principle.


title: Rescattering effects in B_{u,d,s}(bar) to D P, D(bar) P decays

abstract:
  We study quasi-elastic rescattering effects in B_{u,d,s}(bar) to DP, D(bar)P
decays, where P is a light pseudoscalar. The updated measurements of
B_{u,d}(bar) to DP decays are used to extract the effective Wilson coefficients
a^{eff}_1 ~ 0.90, a^{eff}_2 ~ 0.23, three strong phases delta ~ 53 degree,
theta ~ 18 degree, sigma ~ -88 degree, and the mixing angle tau ~ 9 degree.
This information is used to predict rates of nineteen B_{s}(bar) to DP and
B_{u,d,s}(bar) to D(bar)P decay modes, including modes of interests in the
gamma/phi_3 program. Many decay rates are found to be enhanced. In particular,
the B_s(bar) to D0 K0 rate is predicted to be 8\times 10^{-4}, which could be
measured soon. The rescattering effects on the corresponding B_{u,d,s}(bar) to
D(bar)P, DP amplitude ratios r_B, r_{B_s}, and the relative strong phases
delta_B, delta_{B_s} are studied. Although the decay rates are enhanced in most
cases, r_{B,B_s} values are similar to factorization expectation.


title:
Parametrization and Stress-Energy-Momentum Tensors in Metric Field
  Theories

abstract:
  We give an exposition of the parametrization method of Kuchar [1973] in the
context of the multisymplectic approach to field theory, as presented in Gotay
and Marsden [2008a]. The purpose of the formalism developed herein is to make
any classical field theory, containing a metric as a sole background field,
generally covariant (that is, "parametrized," with the spacetime diffeomorphism
group as a symmetry group) as well as fully dynamic. This is accomplished by
introducing certain "covariance fields" as genuine dynamic fields. As we shall
see, the multimomenta conjugate to these new fields form the Piola-Kirchhoff
version of the stress-energy-momentum tensor field, and their Euler-Lagrange
equations are vacuously satisfied. Thus, these fields have no additional
physical content; they serve only to provide an efficient means of
parametrizing the theory. Our results are illustrated with two examples, namely
an electromagnetic field and a Klein-Gordon vector field, both on a background
spacetime.


title:
A Criterion for Vertex Colorability of a Graph Stated in Terms of Edge
  Orientations

abstract:
  L.M.Vitaver [1962] and G.I.Minty [1962] suggested criteria for vertex
colorability of a graph in at most a given number of colors; these criteria are
stated in terms of the orientation of the edges. One additional criterion of
this kind is given here.


title: Robustness of the optical-conductivity sum rule in Bilayer Graphene

abstract:
  We calculate the optical sum associated with the in-plane conductivity of a
graphene bilayer. A bilayer asymmetry gap generated in a field-effect device
can split apart valence and conduction bands, which otherwise would meet at two
K points in the Brillouin zone. In this way one can go from a compensated
semimetal to a semiconductor with a tunable gap. However, the sum rule turns
out to be 'protected' against the opening of this semiconducting gap, in
contrast to the large variations observed in other systems where the gap is
induced by strong correlation effects.


title: Boundary form factors in finite volume

abstract:
  We describe the volume dependence of matrix elements of local boundary fields
to all orders in inverse powers of the volume. Using the scaling boundary
Lee-Yang model as testing ground, we compare the matrix elements extracted from
boundary truncated conformal space approach to exact form factors obtained
using the bootstrap method. We obtain solid confirmation for the boundary form
factor bootstrap, which is different from all previously available tests in
that it is a non-perturbative and direct comparison of exact form factors to
multi-particle matrix elements of local operators, computed from the
Hamiltonian formulation of the quantum field theory.


title: Mid-infrared imaging of brown dwarfs in binary systems

abstract:
  Context: Brown dwarfs exhibit complex atmospheric signatures, and their
properties depend sensitively on effective temperature, surface gravity, and
metallicity. Several physical properties of brown dwarfs in binary systems can
be well inferred from the primary, and therefore allow to better constrain
their atmospheres.
  Aims: We want to constrain atmospheric models of brown dwarfs in binary
systems using narrow-band mid-infrared photometry.
  Methods: High spatial resolution and sensitivity is required to resolve the
components. Therefore we have obtained deep mid-infrared images of four close
binary systems with brown dwarf companions using VISIR at the VLT in three
narrow-band filters at 8.6, 10.5 and 11.25 micron.
  Results: Three brown dwarfs companions (GJ 229B, HD 130948BC and HR 7329B)
were detected at 8.6micron. HD 130948BC was also observed at 10.5micron. We
finally place upper flux limits for the other narrow band filters with null
detections.
  Conclusions: Our results are in general compatible with previous observations
and model expectations for these objects. For HD 130948BC, we conclude
photometric variability on a significance level of 2.8sigma based on repeated
observations. The bandpass around 10.5micron appears specifically well suited
for variability studies, and we speculate that either inhomogeneities in the
atmospheric NH3 distribution, or silicate absorption might cause its
time-variability.


title:
Dynamical and evolutionary constraints on the nature and origin of
  hypervelocity stars

abstract:
  In recent years several hypervelocity stars (HVSs) have been observed in the
halo of our Galaxy. Such stars are thought to be ejected through dynamical
interactions near the massive black hole (MBH) in the Galactic center. Three
scenarios have been suggested for their ejection; binary disruption by a MBH,
scattering by inspiraling IMBH and scattering by stellar BHs close to MBH.
These scenarios involve different stellar populations in the Galactic center.
Here we use observations of the Galactic center stellar population together
with dynamical and evolutionary arguments to obtain strong constraints on the
nature and origin of HVSs. We show that the IMBH inspiral scenario requires too
many (O(10^3)) main sequence B stars to exist close to the MBH (<0.01 pc) at
the time of inspiral, where current observations show O(10) such stars.
Scattering by SBHs also require too many B stars to be observed in the GC, but
it may contribute a small fraction of the currently observed HVSs. The binary
disruption scenario is still consistent with current observations. In addition
it is shown that recently suggested signatures for HVSs origin such as
hypervelocity binaries and slow rotating HVSs are much weaker than suggested
and require too large statistics. In addition, we show that due to the
conditions close to the MBH most binary star systems are not expected to
survive for long in this region. Consequently, unique stellar populations that
require long evolution in binaries are not expected to be ejected as HVSs in
the BHs scattering mechanisms (this may also be related to to the recently
observed asymmetry in the velocity distribution of HVSs).


title: Active one-way quantum computation with 2-photon 4-qubit cluster states

abstract:
  By using 2-photon 4-qubit cluster states we demonstrate deterministic one-way
quantum computation in single qubit rotation algorithm. In this operation
feed-forward measurements are automatically implemented by properly choosing
the measurement basis of the qubits, while Pauli error corrections are realized
by using two fast driven Pockels cells. We realized also a C-NOT gate for
equatorial qubits and a C-Phase gate for a generic target qubit. Our results
demonstrate that 2-photon cluster states can be used for rapid and efficient
deterministic one-way quantum computing.


title:
Measurement of surface concentration of fluorophores using fluorescence
  fluctuation spectroscopy

abstract:
  Fluorescence fluctuation spectroscopy is applied to study molecules, passing
through a small observation volume, usually subjected to diffusive or
convective motion in liquid phase. We suggest that such a technique could be
used to measure the areal absolute concentration of fluorophores deposited on a
substrate or imbedded in a thin film, with a resolution of a few micrometers.
The principle is to translate the solid substrate in front of a confocal
fluorescence microscope objective and to record the subsequent fluctuations of
the fluorescence intensity. The validity of this concept is investigated on
model substrates (fluorescent microspheres) and DNA biochips.


title:
Stabilization of Solitons Generated by a Supersonic Flow of
  Bose-Einstein Condensate Past an Obstacle

abstract:
  Stability of dark solitons generated by a supersonic flow of Bose-Einstein
condensate past an obstacle is investigated. It is shown that in the reference
frame attached to the obstacle a transition occurs at some critical value of
the flow velocity from absolute instability of dark solitons to their
convective instability. This leads to decay of disturbances of solitons at
fixed distance from the obstacle and formation of effectively stable dark
solitons. This phenomenon explains surprising stability of the flow picture
that has been observed in numerical simulations.


title: Determinants of finite-dimensional algebras

abstract:
  To each associative unitary finite-dimensional algebra over a normal base, we
associative a canonical multiplicative function called its determinant. We give
various properties of this construction, as well as applications to the
topology of the moduli stack of n-dimensional algebras.


title: Influence of random roughness on the Casimir force at small separations

abstract:
  The influence of random surface roughness of Au films on the Casimir force is
explored with atomic force microscopy in the plate-sphere geometry. The
experimental results are compared to theoretical predictions for separations
ranging between 20 and 200 nm. The optical response and roughness of the Au
films were measured and used as input in theoretical predictions. It is found
that at separations below 100 nm, the roughness effect is manifested through a
strong deviation from the normal scaling of the force with separation distance.
Moreover, deviations from theoretical predictions based on perturbation theory
can be larger than 100%.


title: The Physics Case Of The SuperB Facility

abstract:
  The physics case of the SuperB facility with design luminosity of 10^36 cm^-2
s^-1 is compelling. Such a facility has a rich and varied potential to probe
physics beyond the Standard Model. These new physics constraints are obtained
through the study of the rare or Standard Model forbidden decays of B_u,d,s, D
and tau particles. The highlights of this wide-ranging physics programme are
discussed in these proceedings.


title: Unoriented D-brane Instantons vs Heterotic worldsheet Instantons

abstract:
  We discuss Fermi interactions of four hyperini generated by ``stringy''
instantons in a Type I / Heterotic dual pair on T^4/Z_2.


title:
Unitary processes with independent increments and representations of
  Hilbert tensor algebras

abstract:
  The aim of this article is to characterize unitary increment process by a
quantum stochastic integral representation on symmetric Fock space. Under
certain assumptions we have proved its unitary equivalence to a
Hudson-Parthasarathy flow.


title:
Real Size And Membership Richness Determination Of High-Latitude Open
  Clusters

abstract:
  We use proper motion measurements to determine the real size and membership
richness of a sample of open clusters located at high galactic latitudes (40 <
|b| < 90).


title:
Multiphoton Transitions in a Spin System Driven by Strong Bichromatic
  Field

abstract:
  EPR transient nutation spectroscopy is used to measure the effective field
(Rabi frequency) for multiphoton transitions in a two-level spin system
bichromatically driven by a transverse microwave (MW) field and a longitudinal
radio-frequency (RF) field. The behavior of the effective field amplitude is
examined in the case of a relatively strong MW field, when the derivation of
the effective Hamiltonian cannot be reduced to first-order perturbation theory
in w_{1} / w_{rf} (w_{1} is the microwave Rabi frequency, w_{rf} is the RF
frequency). Experimental results are consistently interpreted by taking into
account the contributions of second and third order in w_{1} / w_{rf} evaluated
by Krylov-Bogolyubov-Mitropolsky averaging. In the case of inhomogeneously
broadened EPR line, the third-order correction modifies the nutation frequency,
while the second-order correction gives rise to a change in the nutation
amplitude due to a Bloch-Siegert shift.


title: The carbon-rich type Ic SN 2007gr: the photospheric phase

abstract:
  The first two months of spectroscopic and photometric monitoring of the
nearby type Ic SN 2007gr are presented. The very early discovery (less than 5
days after the explosion) and the relatively short distance of the host galaxy
motivated an extensive observational campaign. SN 2007gr shows an average peak
luminosity but unusually narrow spectral lines and an almost flat photospheric
velocity profile. The detection of prominent carbon features in the spectra is
shown and suggest a wide range in carbon abundance in stripped-envelope
supernovae. SN 2007gr may be an important piece in the puzzle of the observed
diversity of CC SNe.


title: Centaurus A: Morphology and kinematics of the HI disk

abstract:
  We present first results of new ATCA HI emission and absorption observations
of Centaurus A. The large-scale disk is described via a tilted-ring model. A
broader redshifted absorption than previously known as well as a blueshifted
absorption component against the nucleus is found.


title: Progress in the Determination of Polarized PDFs and Higher Twist

abstract:
  The impact of the recent very precise CLAS and COMPASS g1/F1 data on
polarized parton densities and higher twist effects is discussed. It is
demonstrated that the low Q^2 CLAS data improve essentially our knowledge of
higher twist corrections to the spin structure function g1, while the large Q^2
COMPASS data influence mainly the strange quark and gluon polarizations. It is
also shown that the uncertainties in the determination of the polarized parton
densities are significantly reduced. We find also that the present inclusive
DIS data cannot rule out a negative polarized and changing in sign gluon
densities. The present status of the proton spin sum rule is discussed.


title:
Link between the laws of geometrical optics and the radiative transfer
  equation in media with a spatially varying refractive index

abstract:
  We proposed in a previous paper [Opt. Commun. 228, 33 (2003)] a modified
radiative transfer equation to describe radiative transfer in a medium with a
spatially varying refractive index. The present paper is devoted to the
demonstration that this equation perfectly works in the non-absorbing /
non-scattering limit, what was contested by L. Mart\'i-L\'opez and coworkers
[Opt. Commun. 266, 44 (2006)]. The assertion that this equation would imply a
zero divergence of the rays is also commented.


title: Cycles of random permutations with restricted cycle lengths

abstract:
  We prove some general results about the asymptotics of the distribution of
the number of cycles of given length of a random permutation whose distribution
is invariant under conjugation. These results were first established to be
applied in a forthcoming paper (Cycles of free words in several random
permutations with restricted cycles lengths), where we prove results about
cycles of random permutations which can be written as free words in several
independent random permutations. However, we also apply them here to prove
asymptotic results about random permutations with restricted cycle lengths.
More specifically, for $A$ a set of positive integers, we consider a random
permutation chosen uniformly among the permutations of $\{1,..., n\}$ which
have all their cycle lengths in $A$, and then let $n$ tend to infinity.
Improving slightly a recent result of Yakymiv (Random A-Permutations:
Convergence to a Poisson Process), we prove that under a general hypothesis on
$A$, the numbers of cycles with fixed lengths of this random permutation are
asymptotically independent and distributed according to Poisson distributions.
In the case where $A$ is finite, we prove that the behavior of these random
variables is completely different: cycles with length $\max A$ are predominant.


title: Probing the submillimetre number counts at f(850um) < 2mJy

abstract:
  We have conducted a submillimetre mapping survey of faint, gravitationally
lensed sources, where we have targeted twelve galaxy clusters and additionally
the NTT Deep Field. The total area surveyed is 71.5 arcmin^2 in the image
plane; correcting for gravitational lensing, the total area surveyed is 40
arcmin^2 in the source plane for a typical source redshift z=2.5. In the
deepest maps, an image plane depth of 1sigma r.m.s. ~0.8 mJy is reached. This
survey is the largest survey to date to reach such depths. In total 59 sources
were detected, including three multiply-imaged sources. The gravitational
lensing makes it possible to detect sources with flux density below the blank
field confusion limit. The lensing corrected fluxes ranges from 0.11 mJy to 19
mJy. After correcting for multiplicity there are 10 sources with fluxes <2 mJy
of which 7 have sub-mJy fluxes, doubling the number of such sources known.
Number counts are determined below the confusion limit. At 1 mJy the integrated
number count is ~10^4 deg^-2, and at 0.5 mJy it is ~2x10^4 deg^-2. Based on the
number counts, at a source plan flux limit of 0.1 mJy, essentially all of the
850um background emission has been resolved. The dominant contribution (> 50
per cent) to the integrated background arises from sources with fluxes S(850)
between 0.4 and 2.5 mJy, while the bright sources S(850) > 6mJy contribute only
10 per cent.


title: Analysis of anisotropy crossover due to oxygen in Pt/Co/MOx trilayer

abstract:
  Extraordinary Hall effect and X-ray spectroscopy measurements have been
performed on a series of Pt/Co/MOx trilayers (M=Al, Mg, Ta...) in order to
investigate the role of oxidation in the onset of perpendicular magnetic
anisotropy at the Co/MOx interface. It is observed that varying the oxidation
time modifies the magnetic properties of the Co layer, inducing a magnetic
anisotropy crossover from in-plane to out-of-plane. We focused on the influence
of plasma oxidation on Pt/Co/AlOx perpendicular magnetic anisotropy. The
interfacial electronic structure is analyzed via X-ray photoelectron
spectroscopy measurements. It is shown that the maximum of out-of-plane
magnetic anisotropy corresponds to the appearance of a significant density of
Co-O bondings at the Co/AlOx interface.


title:
Suzaku observations of Markarian 335: evidence for a distributed
  reflector

abstract:
  We report on a 151 ks net exposure Suzaku observation of the Narrow Line
Seyfert 1 galaxy Mrk 335. The 0.5-40 keV spectrum contains a broad Fe line, a
strong soft excess below about 2 keV and a Compton hump around 20-30 keV. We
find that a model consisting of a power law and two reflectors provides the
best fit to the time-averaged spectrum. In this model, an ionized, heavily
blurred, inner reflector produces most of the soft excess, while an almost
neutral outer reflector (outside ~40 r_g) produces most of the Fe line
emission. The spectral variability of the observation is characterised by
spectral hardening at very low count rates. In terms of our power-law +
two-reflector model it seems like this hardening is mainly caused by pivoting
of the power law. The rms spectrum of the entire observation has the curved
shape commonly observed in AGN, although the shape is significantly flatter
when an interval which does not contain any deep dip in the lightcurve is
considered. We also examine a previous 133 ks XMM-Newton observation of Mrk
335. We find that the XMM-Newton spectrum can be fitted with a similar
two-reflector model as the Suzaku data and we confirm that the rms spectrum of
the observation is flat. The flat rms spectra, as well as the high-energy data
from the Suzaku PIN detector, disfavour an absorption origin for the soft
excess in Mrk 335.


title: Dynamical evolution of the Gliese 581 planetary system

abstract:
  We address the issue of the dynamical evolution of the Gliese 581 planetary
system. It is crucial when considering the planets' habitability because the
secular evolution of the orbits may regulate their climate, even in the case
where the system is stable. We have numerically integrated the planetary system
over 10^8 yrs, starting from the present fitted solution. In all cases, the
system appears dynamically stable, even in close to pole-on configurations.
Only a limited range of inclinations can be excluded. The climate on the
planets is expected to be secularly stable, thus not precluding the development
of life. Gl 581 remains the best candidate for a planetary system with planets
that potentially bear primitive forms of life.


title:
Quantum Zeno Effect in the Quantum Non-Demolition Detection of Itinerant
  Photons

abstract:
  We analyze the detection of itinerant photons using a quantum non-demolition
(QND) measurement. We show that the backaction due to the continuous
measurement imposes a limit on the detector efficiency in such a scheme. We
illustrate this using a setup where signal photons have to enter a cavity in
order to be detected dispersively. In this approach, the measurement signal is
the phase shift imparted to an intense beam passing through a second cavity
mode. The restrictions on the fidelity are a consequence of the Quantum Zeno
effect, and we discuss both analytical results and quantum trajectory
simulations of the measurement process.


title:
Upper limit on the diffuse flux of UHE tau neutrinos from the Pierre
  Auger Observatory

abstract:
  The surface detector array of the Pierre Auger Observatory is sensitive to
Earth-skimming tau-neutrinos $\nu_\tau$ that interact in the Earth's crust. Tau
leptons from $\nu_\tau$ charged-current interactions can emerge and decay in
the atmosphere to produce a nearly horizontal shower with a significant
electromagnetic component. The data collected between 1 January 2004 and 31
August 2007 is used to place an upper limit on the diffuse flux of $\nu_\tau$
at EeV energies. Assuming an $E_\nu^{-2}$ differential energy spectrum the
limit set at 90 % C.L. is $E_\nu^{2} \mathrm{d}N_{\nu_\tau}/\mathrm{d}E_{\nu} <
1.3 \times 10^{-7}$ GeV cm$^{-2}$ s$^{-1}$ sr$^{-1}$ in the energy range
$2\times10^{17} \mathrm{eV} < E_\nu < 2\times10^{19}$ eV.


title:
Distinguishing quantum from classical oscillations in a driven phase
  qubit

abstract:
  Rabi oscillations are coherent transitions in a quantum two-level system
under the influence of a resonant perturbation, with a much lower frequency
dependent on the perturbation amplitude. These serve as one of the signatures
of quantum coherent evolution in mesoscopic systems. It was shown recently [N.
Gronbech-Jensen and M. Cirillo, Phys. Rev. Lett. 95, 067001 (2005)] that in
phase qubits (current-biased Josephson junctions) this effect can be mimicked
by classical oscillations arising due to the anharmonicity of the effective
potential. Nevertheless, we find qualitative differences between the classical
and quantum effect. First, while the quantum Rabi oscillations can be produced
by the subharmonics of the resonant frequency (multiphoton processes), the
classical effect also exists when the system is excited at the overtones.
Second, the shape of the resonance is, in the classical case,
characteristically asymmetric; while quantum resonances are described by
symmetric Lorentzians. Third, the anharmonicity of the potential results in the
negative shift of the resonant frequency in the classical case, in contrast to
the positive Bloch-Siegert shift in the quantum case. We show that in the
relevant range of parameters these features allow to confidently distinguish
the bona fide Rabi oscillations from their classical Doppelganger.


title: Three-body resonances Lambda-n-n and Lambda-Lambda-n

abstract:
  Possible bound and resonant states of the hypernuclear systems $\Lambda nn$
and $\Lambda\Lambda n$ are sought as zeros of the corresponding three-body Jost
functions calculated within the framework of the hyperspherical approach with
local two-body S-wave potentials describing the $nn$, $\Lambda n$, and
$\Lambda\Lambda$ interactions. Very wide near-threshold resonances are found
for both three-body systems. The positions of these resonances turned out to be
sensitive to the choice of the $\Lambda n$-potential. Bound $\Lambda nn$ and
$\Lambda\Lambda n$ states only appear if the two-body potentials are multiplied
by a factor of $\sim 1.5$.


title:
Holographic approach to deformations of NS5-brane distributions and
  exact CFTs

abstract:
  We consider general planar deformations of a circular distribution of
NS5-branes. The near-horizon region of the latter admits, after a T-duality
transformation, an exact conformal-field-theory description in terms of the
coset model SU(2)/U(1) X SL(2,R)/U(1). We derive the exactly marginal operators
corresponding to an infinitesimal planar deformation using the conjectured
holography between the coset model and the little string theory that resides on
the worldvolume of the NS5-branes. Subsequently, we perform a complementary
analysis of the same deformations using the associated N=1 supersymmetric sigma
model and verify the holographic correspondence. We explicitly demonstrate a
precise match between the two approaches which rests upon a delicate interplay
between exact conformal-field-theory operators and their semiclassical
realizations in terms of target-space variables.


title: CMB polarization constraints on radiative feedback

abstract:
  We compute the imprints left on the CMB by two cosmic reionization models
consistent with current observations but characterized by alternative radiative
feedback prescriptions (suppression and filtering) resulting in a different
suppression of star formation in low-mass halos. The models imply different
ionization and thermal histories and 21 cm background signals. The derived
Comptonization, u, and free-free distortion, y_B, parameters are below current
observational limits for both models. However, the value of u = 1.69 * 10^-7
(9.65 * 10^-8) for the suppression (filtering) model is in the detectability
range of the next generation of CMB spectrum experiments. Through the dedicated
Boltzmann code CMBFAST, modified to include the above ionization histories, we
compute the CMB angular power spectrum (APS) of the TT, TE, and EE modes. For
the EE mode the differences between these models are significantly larger than
the cosmic and sampling variance over the multipole range l = 5-15, leaving a
good chance of discriminating between these feedback mechanisms with
forthcoming/future CMB polarization experiments. The main limitations come from
foreground contamination: it should be subtracted at per cent level in terms of
APS, a result potentially achievable by novel component separation techniques
and mapping of Galactic foreground.


title: Universality of REM-like aging in mean field spin glasses

abstract:
  Aging has become the paradigm to describe dynamical behavior of glassy
systems, and in particular spin glasses. Trap models have been introduced as
simple caricatures of effective dynamics of such systems. In this Letter we
show that in a wide class of mean field models and on a wide range of time
scales, aging occurs precisely as predicted by the REM-like trap model of
Bouchaud and Dean. This is the first rigorous result about aging in mean field
models except for the REM and the spherical model.


title: Ground State Hyperfine Structure of Muonic Helium Atom

abstract:
  On the basis of the perturbation theory in the fine structure constant
$\alpha$ and the ratio of the electron to muon masses we calculate one-loop
vacuum polarization and electron vertex corrections and the nuclear structure
corrections to the hyperfine splitting of the ground state of muonic helium
atom $(\mu e ^4_2He)$. We obtain total result for the ground state hyperfine
splitting $\Delta \nu^{hfs}=4465.526$ MHz which improves the previous
calculation of Lakdawala and Mohr due to the account of new corrections. The
remaining difference between the theoretical result and experimental value of
the hyperfine splitting equal to 0.522 MHz lies in the range of theoretical
error and requires the subsequent investigation of higher order corrections.


title: Ranking forestry journals using the h-index

abstract:
  An expert ranking of forestry journals was compared with journal impact
factors and h-indices computed from the ISI Web of Science and internet-based
data. Citations reported by Google Scholar appear to offer the most efficient
way to rank all journals objectively, in a manner consistent with other
indicators. This h-index exhibited a high correlation with the journal impact
factor (r=0.92), but is not confined to journals selected by any particular
commercial provider. A ranking of 180 forestry journals is presented, on the
basis of this index.


title: Are solar cycles predictable?

abstract:
  Various methods (or recipes) have been proposed to predict future solar
activity levels - with mixed success. Among these, some precursor methods based
upon quantities determined around or a few years before solar minimum have
provided rather high correlations with the strength of the following cycles.
Recently, data assimilation with an advection-dominated (flux-transport) dynamo
model has been proposed as a predictive tool, yielding remarkably high
correlation coefficients. After discussing the potential implications of these
results and the criticism that has been raised, we study the possible physical
origin(s) of the predictive skill provided by precursor and other methods. It
is found that the combination of the overlap of solar cycles and their
amplitude-dependent rise time (Waldmeier's rule) introduces correlations in the
sunspot number (or area) record, which account for the predictive skill of many
precursor methods. This explanation requires no direct physical relation
between the precursor quantity and the dynamo mechanism (in the sense of the
Babcock-Leighton scheme or otherwise).


title: Binary linear forms as sums of two squares

abstract:
  We revisit recent work of Heath-Brown on the average order of the quantity
r(L_1)r(L_2)r(L_3)r(L_4), for suitable binary linear forms L_1,..., L_4, for
integers ranging over quite general regions. In addition to improving the error
term in Heath-Brown's estimate we generalise his result quite extensively.