title: On the deduction of galaxy abundances with evolutionary neural networks

abstract:
  A growing number of indicators are now being used with some confidence to
measure the metallicity(Z) of photoionisation regions in planetary nebulae,
galactic HII regions(GHIIRs), extra-galactic HII regions(EGHIIRs) and HII
galaxies(HIIGs). However, a universal indicator valid also at high
metallicities has yet to be found. Here, we report on a new artificial
intelligence-based approach to determine metallicity indicators that shows
promise for the provision of improved empirical fits. The method hinges on the
application of an evolutionary neural network to observational emission line
data. The network's DNA, encoded in its architecture, weights and neuron
transfer functions, is evolved using a genetic algorithm. Furthermore,
selection, operating on a set of 10 distinct neuron transfer functions, means
that the empirical relation encoded in the network solution architecture is in
functional rather than numerical form. Thus the network solutions provide an
equation for the metallicity in terms of line ratios without a priori
assumptions. Tapping into the mathematical power offered by this approach, we
applied the network to detailed observations of both nebula and auroral
emission lines in the optical for a sample of 96 HII-type regions and we were
able to obtain an empirical relation between Z and S23 with a dispersion of
only 0.16 dex. We show how the method can be used to identify new diagnostics
as well as the nonlinear relationship supposed to exist between the metallicity
Z, ionisation parameter U and effective (or equivalent) temperature T*.


title:
General Operator Solutions and BRST Quantization of Superstrings in the
  pp-Wave with Torsion

abstract:
  We completely accomplish the canonically covariant quantization of
Ramond-Neveu-Schwarz (RNS) superstrings in the pp-wave background with a
non-zero flux of the NS-NS antisymmetric two-form field. Here this flux is
equivalent to a nonvanishing torsion. In this quantization, general operator
solutions, which satisfy the entire equation of motion and all the canonical
(anti)commutation relations, play an important role. The whole of covariant
string coordinates and fermions can be composed of free modes. Moreover,
employing covariant free-mode representations, we calculate the anomaly in the
super-Virasoro algebra and determine the number of dimensions of spacetime and
the ordering constant from the nilpotency condition of the BRST charge in the
pp-wave background with the flux.


title:
From matrix models' topological expansion to topological string
  theories: counting surfaces with algebraic geometry

abstract:
  The 2-matrix model has been introduced to study Ising model on random
surfaces. Since then, the link between matrix models and combinatorics of
discrete surfaces has strongly tightened. This manuscript aims to investigate
these deep links and extend them beyond the matrix models, following my work's
evolution. First, I take care to define properly the hermitian 2 matrix model
which gives rise to generating functions of discrete surfaces equipped with a
spin structure. Then, I show how to compute all the terms in the topological
expansion of any observable by using algebraic geometry tools. They are
obtained as differential forms on an algebraic curve associated to the model:
the spectral curve. In a second part, I show how to define such differentials
on any algebraic curve even if it does not come from a matrix model. I then
study their numerous symmetry properties under deformations of the algebraic
curve. In particular, I show that these objects coincide with the topological
expansion of the observable of a matrix model if the algebraic curve is the
spectral curve of this model. Finally, I show that fine tuning the parameters
ensure that these objects can be promoted to modular invariants and satisfy the
holomorphic anomaly equation of the Kodaira-Spencer theory. This gives a new
hint that the Dijkgraaf-Vafa conjecture is correct.


title: The Astronomy and Science Behind the Myth

abstract:
  We show that many ancient Indian mythological legends are really allegorical
depictions of astronomical and other physical phenomena of which the composers
had a good idea. This detail enables us to also use techniques of astronomical
chronology for dating various events.


title:
CP violation at one loop in the polarization-independent chargino
  production in e+e- collisions

abstract:
  Recently Osland and Vereshagin noticed, based on sample calculations of some
box diagrams, that in unpolarised e+e- collisions CP-odd effects in the
non-diagonal chargino-pair production process are generated at one-loop. Here
we perform a full one-loop analysis of these effects and point out that in some
cases the neglected vertex and self-energy contributions may play a dominant
role. We also show that CP asymmetries in chargino production are sensitive not
only to the phase of mu parameter in the chargino sector but also to the phase
of stop trilinear coupling A_t.


title: C*-pseudo-multiplicative unitaries

abstract:
  We introduce $C^*$-pseudo-multiplicative unitaries and (concrete) Hopf
$C^*$-bimodules, which are $C^*$-algebraic variants of the
pseudo-multiplicative unitaries on Hilbert spaces and the Hopf-von
Neumann-bimodules studied by Enock, Lesieur, Vallin. Moreover, we associate to
every regular $C^*$-pseudo-multiplicative unitary two Hopf-$C^*$-bimodules and
discuss examples related to locally compact groupoids.


title: Entanglement-free Heisenberg-limited phase estimation

abstract:
  Measurement underpins all quantitative science. A key example is the
measurement of optical phase, used in length metrology and many other
applications. Advances in precision measurement have consistently led to
important scientific discoveries. At the fundamental level, measurement
precision is limited by the number N of quantum resources (such as photons)
that are used. Standard measurement schemes, using each resource independently,
lead to a phase uncertainty that scales as 1/sqrt(N) - known as the standard
quantum limit. However, it has long been conjectured that it should be possible
to achieve a precision limited only by the Heisenberg uncertainty principle,
dramatically improving the scaling to 1/N. It is commonly thought that
achieving this improvement requires the use of exotic quantum entangled states,
such as the NOON state. These states are extremely difficult to generate.
Measurement schemes with counted photons or ions have been performed with N <=
6, but few have surpassed the standard quantum limit and none have shown
Heisenberg-limited scaling. Here we demonstrate experimentally a
Heisenberg-limited phase estimation procedure. We replace entangled input
states with multiple applications of the phase shift on unentangled
single-photon states. We generalize Kitaev's phase estimation algorithm using
adaptive measurement theory to achieve a standard deviation scaling at the
Heisenberg limit. For the largest number of resources used (N = 378), we
estimate an unknown phase with a variance more than 10 dB below the standard
quantum limit; achieving this variance would require more than 4,000 resources
using standard interferometry. Our results represent a drastic reduction in the
complexity of achieving quantum-enhanced measurement precision.


title: Two polynomial representations of experimental design

abstract:
  In the context of algebraic statistics an experimental design is described by
a set of polynomials called the design ideal. This, in turn, is generated by
finite sets of polynomials. Two types of generating sets are mostly used in the
literature: Groebner bases and indicator functions. We briefly describe them
both, how they are used in the analysis and planning of a design and how to
switch between them. Examples include fractions of full factorial designs and
designs for mixture experiments.


title:
Cavity-assisted spontaneous emission as a single-photon source: Pulse
  shape and efficiency of one-photon Fock state preparation

abstract:
  Within the framework of exact quantum electrodynamics in dispersing and
absorbing media, we have studied the quantum state of the radiation emitted
from an initially in the upper state prepared two-level atom in a high-$Q$
cavity, including the regime where the emitted photon belongs to a wave packet
that simultaneously covers the areas inside and outside the cavity. For both
continuing atom--field interaction and short-term atom--field interaction, we
have determined the spatio-temporal shape of the excited outgoing wave packet
and calculated the efficiency of the wave packet to carry a one-photon Fock
state. Furthermore, we have made contact with quantum noise theories where the
intracavity field and the field outside the cavity are regarded as
approximately representing independent degrees of freedom such that two
separate Hilbert spaces can be introduced.


title: A Criterion for Precompactness in the Space of Hypermeasures

abstract:
  Let $Q$ denote the space of signed measures on the Borel $\sigma$-algebra of
a separable complete space $X$. We endow $Q$ with the norm $\|q\|=\sup|\int\phi
dq|$, where the supremum is taken over all Lipschitz with constant 1 functions
whose module does not exceed unity. This normed space is incomplete provided
$X$ is infinite and has at least one limit point. We call its completion the
space of hypermeasures. Necessary and sufficient conditions for precompactness
(=relative compactness) of a set of hypermeasures are found. They are similar
to those of Prokhorov's and Fernique's theorems for measures.


title: Cool carbon stars in the halo: new very red or distant objects

abstract:
  The goal of this paper is to present and analyse a new sample of cool carbon
(C)stars located in the halo. Twenty three new C stars were discovered. Spectra
are typical of N-type stars with C2 and CN bands and sometimes Halpha in
emission. ... Four objects are particularly red with J-K > 3, with 2 located at
more than 5 kpc. from the Galactic plane. Eight additional objects with similar
properties are found in the literature and our previous works. These 12 C stars
could be useful to study mass loss at low metallicity. Two objects are at
distances of 95 and 110 kpc. They are located in the region with galactocentric
Z < -60 kpc in which the model of Law et al. predicts the Sgr stream to have a
loop. (Abstact abridged)


title:
Description of superdeformed bands in light N=Z nuclei using the cranked
  HFB method

abstract:
  Superdeformed states in light $N=Z$ nuclei are studied by means of the
self-consistent cranking calculation (i.e., the P + QQ model based on the
cranked Hartree-Fock-Bogoliubov method). Analyses are given for two typical
cases of superdeformed bands in the $A \simeq 40$ mass region, that is, bands
where backbending is absent ($^{40}$Ca) and present ($^{36}$Ar). Investigations
are carried out, particularly for the following points: cross-shell excitations
in the sd and pf shells; the role of the g$_{9/2}$ and d$_{5/2}$ orbitals; the
effect of the nuclear pairing; and the interplay between triaxiality and band
termination.


title: A generalized Principle of Relativity

abstract:
  In this paper we bring to light an hitherto undisclosed richness of this
Theory, namely its admitting a consistent reformulation which is able to
provide a unified scenario for all kinds of particles, be they lightlike or
not. This result hinges on a "generalized" Principle of Relativity which is
{intrinsic} to Einstein's Theory. The road leading to this generalization
starts, in the very spirit of Relativity, from enhancing full equivalence
between the four spacetime directions by requiring full equivalence between the
"motions" along these four spacetime directions as well. So far, no measurable
spatial velocity in the direction of the time axis has ever been defined, on
the same footing of the usual velocities in the local three-space of a given
observer. In this paper, we show how Relativity allows such a "time-velocity"
to be defined in a very natural way, for any particle and in any reference
frame. As a consequence of this natural definition, it also follows that the
time- and space-velocity vectors sum up to define a spacelike "world-velocity"
vector, the modulus of which turns out to be equal to the Maxwell's constant c,
irrespective of the observer who measures it. This {measurable} world-velocity
therefore represents the speed at which "all" kinds of particles move in
spacetime, according to any observer. As remarked above, the unifying scenario
thus emerging is intrinsic to Einstein's Theory; it extends the role
traditionally assigned to Maxwell's constant c, and can therefore justly be
referred to as "a generalized Principle of Relativity".


title: Coherent backscattering of ultrasound without a source

abstract:
  Coherent backscattering is due to constructive interferences of reciprocal
paths and leads to an enhancement of the intensity of a multiply scattered
field near its source. To observe this enhancement an array of receivers is
conventionally placed close to the source. Our approach here is different. In a
first experiment, we recover the coherent backscattering effect (CBE) within an
array of sources and a distant receiver using time correlation of diffuse
fields. The enhancement cone has an excellent spatial resolution. The dynamics
of the enhancement factor is studied in a second experiment using correlation
of thermal phonons at the same ultrasonic frequencies, without any active
source.

categories: cond-mat.other cond-mat.stat-mech physics.class-ph physics.geo-ph


title:
A FLAMINGOS Deep Near Infrared Imaging Survey of the Rosette Complex I:
  Identification and Distribution of the Embedded Population

abstract:
  We present the results of a deep near-infrared imaging survey of the Rosette
Complex. We studied the distribution of young embedded sources using a
variation of the Nearest Neighbor Method applied to a carefully selected sample
of near-infrared excess (NIRX) stars which trace the latest episode of star
formation in the complex. Our analysis confirmed the existence of seven
clusters previously detected in the molecular cloud, and identified four more
clusters across the complex. We determined that 60% of the young stars in the
complex and 86% of the stars within the molecular cloud are contained in
clusters, implying that the majority of stars in the Rosette formed in embedded
clusters. We compare the sizes, infrared excess fractions and average
extinction towards individual clusters to investigate their early evolution and
expansion. We found that the average infrared excess fraction of clusters
increases as a function of distance from NGC 2244, implying a temporal sequence
of star formation across the complex. This sequence appears to be primordial,
possibly resulting from the formation and evolution of the molecular cloud and
not from the interaction with the HII region.


title: Feedback and efficiency in limit order markets

abstract:
  A consistency criterion for price impact functions in limit order markets is
proposed that prohibits chain arbitrage exploitation. Both the bid-ask spread
and the feedback of sequential market orders of the same kind onto both sides
of the order book are essential to ensure consistency at the smallest time
scale. All the stocks investigated in Paris Stock Exchange have consistent
price impact functions.


title:
Soliton-like Spin State in the A-like Phase of 3He in Anisotropic
  Aerogel

abstract:
  We have found a new stable spin state in the A-like phase of superfluid 3He
confined to intrinsically anisotropic aerogel. The state can be formed by
radiofrequency excitation applied while cooling through the superfluid
transition temperature and its NMR properties are different from the standard
A-like phase obtained in the limit of very small excitation. It is possible
that this new state is formed by textural domain walls pinned by aerogel.


title: Mass loss predictions for hot stars

abstract:
  I present the results of radiation-driven mass-loss predictions for hot stars
of all mass. Mass loss is an important aspect for the evolution of massive
stars, the rotational properties of the progenitors of gamma-ray bursts, and is
essential in assessing whether the most massive stars explode as
pair-instability supernovae, or avoid them due to mass loss. As a result, the
rate of mass loss is critical for our understanding of the chemical enrichment
of the Universe. Of particular interest is the question whether luminous blue
variables are the direct progenitors of some supernovae. Although there is a
growing body of evidence to suggest this, it remains as yet unexplained by
state-of-the-art stellar evolution models. Finally, I discuss the relevance of
mass loss for the appearance and rotational properties of hot Horizontal Branch
stars in globular clusters and subdwarf B stars in the field.


title: Magnetic flux emergence in fast rotating stars

abstract:
  Fast rotating cool stars are characterised by high magnetic activity levels
and frequently show dark spots up to polar latitudes. Their distinctive surface
distributions of magnetic flux are investigated in the context of the
solar-stellar connection by applying the solar flux eruption and surface flux
transport models to stars with different rotation rates, mass, and evolutionary
stage. The rise of magnetic flux tubes through the convection zone is primarily
buoyancy-driven, though their evolution can be strongly affected by the
Coriolis force. The poleward deflection of the tube's trajectory increases with
the stellar rotation rate, which provides an explanation for magnetic flux
eruption at high latitudes. The formation of proper polar spots likely requires
the assistance of meridional flows both before and after the eruption of
magnetic flux on the stellar surface. Since small radiative cores support the
eruption of flux tubes at high latitudes, low-mass pre-main sequence stars are
predicted to show high mean latitudes of flux emergence. In addition to flux
eruption at high latitudes, main sequence components of close binary systems
show spot distributions which are non-uniform in longitude. Yet these
`preferred longitudes' of flux eruption are expected to vanish beyond a certain
post-main sequence evolutionary stage.


title:
^{63,65}Cu NMR and NQR evidence for an unusual spin dynamics in PrCu_2
  below 100 K

abstract:
  We report the results of a $^{63,65}$Cu NMR/NQR study probing the
intermetallic compound PrCu$_2$. The previously claimed onset of magnetic order
at 65 K, indicated in a $\mu$SR study, is not confirmed. Based on our data we
discuss different possible reasons for this apparent discrepancy, including a
non negligible influence of the implanted muons on their environment. Competing
dipolar and quadrupolar interactions lead to unusual features of the
magnetic-ion/conduction-electron system, different from those of common
intermetallics exhibiting structural or magnetic instabilities.


title: BFKL ansatz for BK equation in conformal basis

abstract:
  The BK equation in the conformal basis is considered and analyzed. It is
shown that at high energy a factorization of the coordinate and rapidity
dependence should hold. This allows to simplify significantly the from of the
equation under discussion. An analytical ansatz for the solution to the BK
equation at high energies is proposed and analyzed. This analytical ansatz
satisfies the initial condition at low energy and does not depend on both
rapidity and the initial condition in the high energy limit. The case of the
final rapidity being not too large is discussed and the properties of the
transition region between small and large final rapidities have been studied.


title: Some extensions of the uncertainty principle

abstract:
  We study the formulation of the uncertainty principle in quantum mechanics in
terms of entropic inequalities, extending results recently derived by
Bialynicki-Birula [1] and Zozor et al. [2]. Those inequalities can be
considered as generalizations of the Heisenberg uncertainty principle, since
they measure the mutual uncertainty of a wave function and its Fourier
transform through their associated R\'enyi entropies with conjugated indices.
We consider here the general case where the entropic indices are not
conjugated, in both cases where the state space is discrete and continuous: we
discuss the existence of an uncertainty inequality depending on the location of
the entropic indices $\alpha$ and $\beta$ in the plane $(\alpha, \beta)$. Our
results explain and extend a recent study by Luis [2], where states with
quantum fluctuations below the Gaussian case are discussed at the single point
$(2,2)$.


title: Construction of a stationary queue with impatient customers

abstract:
  In this paper, we study the stability of queues with impatient customers.
Under general stationary ergodic assumptions, we first provide some conditions
for such a queue to be regenerative (i.e. to empty a.s. an infinite number of
times). In the particular case of a single server operating in First in, First
out, we prove the existence (in some cases, on an enlarged probability space)
of a stationary workload. This is done by studying a non-monotonic stochastic
recursion under the Palm settings, and by stochastic comparison of stochastic
recursions.


title:
Supervised learning on graphs of spatio-temporal similarity in satellite
  image sequences

abstract:
  High resolution satellite image sequences are multidimensional signals
composed of spatio-temporal patterns associated to numerous and various
phenomena. Bayesian methods have been previously proposed in (Heas and Datcu,
2005) to code the information contained in satellite image sequences in a graph
representation using Bayesian methods. Based on such a representation, this
paper further presents a supervised learning methodology of semantics
associated to spatio-temporal patterns occurring in satellite image sequences.
It enables the recognition and the probabilistic retrieval of similar events.
Indeed, graphs are attached to statistical models for spatio-temporal
processes, which at their turn describe physical changes in the observed scene.
Therefore, we adjust a parametric model evaluating similarity types between
graph patterns in order to represent user-specific semantics attached to
spatio-temporal phenomena. The learning step is performed by the incremental
definition of similarity types via user-provided spatio-temporal pattern
examples attached to positive or/and negative semantics. From these examples,
probabilities are inferred using a Bayesian network and a Dirichlet model. This
enables to links user interest to a specific similarity model between graph
patterns. According to the current state of learning, semantic posterior
probabilities are updated for all possible graph patterns so that similar
spatio-temporal phenomena can be recognized and retrieved from the image
sequence. Few experiments performed on a multi-spectral SPOT image sequence
illustrate the proposed spatio-temporal recognition method.


title: Future precision neutrino experiments and their theoretical implications

abstract:
  Future neutrino oscillation measurement focus, at first priority, on the
discovery of sin^2(2 theta_13) describing the coupling between solar and
atmospheric oscillations. In this talk, we briefly discuss the prospects to
measure sin^2(2 theta_13) by future reactor and beam experiments, and we
illustrate the usefulness of these measurements (and their precision) from the
theoretical point of view with an example.


title: Observational evidence for AGN feedback in early-type galaxies

abstract:
  A major amendment in recent models of hierarchical galaxy formation is the
inclusion of so-called AGN feedback. The energy input from an active central
massive black hole is invoked to suppress star formation in early-type galaxies
at later epochs. A major problem is that this process is poorly understood, and
compelling observational evidence for its mere existence is still missing. In
search for signatures of AGN feedback, we have compiled a sample of 16,000
early-type galaxies in the redshift range 0.05<z<0.1 from the SDSS database.
Key in our approach is the use of a purely morphological selection criterion
through visual inspection which produces a sample that is not biased against
recent star formation and nuclear activity. The objects with emission (~20 per
cent) are offset from the red sequence and form a well-defined pattern in the
colour-mass diagram. Star forming early-types inhabit the blue cloud, while
early-types with AGN are located considerably closer to and almost on the red
sequence. Star formation-AGN composites are found right between these two
extremes. We further derive galaxy star formation histories using a novel
method that combines multiwavelength photometry from near-UV to near-IR and
stellar absorption indices. We find that in those objects deviating from the
red sequence star formation occurred several 100 Myr in the past involving 1-10
per cent of the total stellar mass. We identify an evolutionary sequence from
star formation via nuclear activity to quiescence. This transition process
lasts about 1 Gyr, and the peak AGN phase occurs roughly half a Gyr after the
starburst. The most likely interpretation is that star formation is suppressed
by nuclear activity in these objects before they settle on the red sequence.


title: On the ideal $(v^0)$

abstract:
  The $\sigma$-ideal $(v^0)$ is associated with the Silver forcing, see
\cite{bre}. Also, it constitutes the family of all completely doughnut null
sets, see \cite{hal}. We introduce segments and $*$-segments topologies, to
state some resemblances of $(v^0)$ to the family of Ramsey null sets. To
describe $add(v^0)$ we adopt a proof of Base Matrix Lemma. Consistent results
are stated, too. Halbeisen's conjecture $cov(v^0) = add(v^0)$ is confirmed
under the hypothesis $t= \min \{\cf (\frak c), r\} $. The hypothesis
$h=\omega_1$ implies that $(v^0)$ has the ideal type $(\frak c, \omega_1,\frak
c)$.


title: Emergent Fermions and Anyons in the Kitaev Model

abstract:
  We study the gapped phase of the Kitaev model on the honeycomb lattice using
perturbative continuous unitary transformations. The effective low-energy
Hamiltonian is found to be an extended toric code with interacting anyons.
High-energy excitations are emerging free fermions which are composed of
hardcore bosons with an attached string of spin operators. The excitation
spectrum is mapped onto that of a single particle hopping on a square lattice
in a magnetic field. We also illustrate how to compute correlation functions in
this framework. The present approach yields analytical perturbative results in
the thermodynamical limit without using the Majorana or the Jordan-Wigner
fermionization initially proposed to solve this problem.


title:
Nature and statistics of majority rankings in a dynamical model of
  preference aggregation

abstract:
  We present numerical results on a complex dynamical model for the aggregation
of many individual rankings of S alternatives by the pairwise majority rule
under a deliberative scenario. Agents are assumed to interact when the Kemeny
distance between their rankings is smaller than a range R. The main object of
interest is the probability that the aggregate (social) ranking is transitive
as a function of the interaction range. This quantity is known to decay fast as
S increases in the non-interacting case. Here we find that when S>4 such a
probability attains a sharp maximum when the interaction range is sufficiently
large, in which case it significantly exceeds the corresponding value for a
non-interacting system. Furthermore, the situation improves upon increasing S.
A possible microscopic mechanism leading to this counterintuitive result is
proposed and investigated.


title: Neutrino-induced coherent pion production

abstract:
  We have investigated the neutrino induced coherent pion production reaction
at the energies of interest for recent experiments like K2K and MiniBooNE. The
model includes pion, nucleon and the Delta(1232) resonance. Medium effects in
the production mechanism and the distortion of the pion wave function are taken
into account. We find a strong reduction of the cross section due to these
effects and also substantial modifications in the energy distributions of the
final pion. The sensitivity of the results on the axial N-Delta coupling C5A(0)
and the coherent fraction in neutral-current pi0 production are discussed.


title: Transverse momentum dependence of semi-inclusive pion production

abstract:
  Cross sections for semi-inclusive electroproduction of charged pions
($\pi^{\pm}$) from both proton and deuteron targets were measured for
$0.2<x<0.5$, $2<Q^2<4$ GeV$^2$, $0.3<z<1$, and $P_t^2<0.2$ GeV$^2$. For
$P_t<0.1$ GeV, we find the azimuthal dependence to be small, as expected
theoretically. For both $\pi^+$ and $\pi^-$, the $P_t$ dependence from the
deuteron is found to be slightly weaker than from the proton. In the context of
a simple model, this implies that the initial transverse momenta width of $d$
quarks is larger than for $u$ quarks and, contrary to expectations, the
transverse momentum width of the favored fragmentation function is larger than
the unfavored one.


title:
Hankel hyperdeterminants, rectangular Jack polynomials and even powers
  of the Vandermonde

abstract:
  We investigate the link between rectangular Jack polynomials and Hankel
hyperdeterminants. As an application we give an expression of the even power of
the Vandermonde in term of Jack polynomials.


title: BCB Based Packaging for Low Actuation Voltage RF MEMS Devices

abstract:
  This paper outlines the issues related to RF MEMS packaging and low actuation
voltage. An original approach is presented concerning the modeling of
capacitive contacts using multiphysics simulation and advanced
characterization. A similar approach is used concerning packaging development
where multi-physics simulations are used to optimize the process. A devoted
package architecture is proposed featuring very low loss at microwave range.


title:
IGR J22517+2218=MG3 J225155+2217: a new gamma-ray lighthouse in the
  distant Universe

abstract:
  We report on the identification of a new soft gamma ray source, namely IGR
J22517+2218, detected with IBIS/INTEGRAL. The source, which has an observed
20-100 keV flux of ~4 x10^-11 erg cm-2 s-1, is spatially coincident with MG3
J225155+2217, a quasar at z=3.668. The Swift/XRT 0.5-10 keV continuum is flat
(Gamma=1.5) with evidence for a spectral curvature below 1-2 keV either due to
intrinsic absorption (NH=3 +/- 2 x 10^22 cm-2) or to a change in slope (Delta
Gamma= 0.5). X-ray observations indicate flux variability over a 6 days period
which is further supported by a flux mismatch between Swift and INTEGRAL
spectra. IGR J22517+2218 is radio loud and has a flat radio spectrum; optically
it is a broad line emitting quasar with the atypical property of hosting a
narrow line absorption system. The Source Spectral Energy Distribution is
unusual compared to blazars of similar type: either it has the synchrotron peak
in the X/gamma-ray band (i.e. much higher than generally observed) or the
Compton peak in the MeV range (i.e. lower than typically measured). IGR
J22517+2218=MG3 J225155+2217 is the second most distant blazar detected above
20 keV and a gamma-ray lighthouse shining from the edge of our Universe.


title: Non-linear self-consistent response of graphene in time domain

abstract:
  We study the non-linear electromagnetic response of graphene taking into
account the self-consistent-field effects. Response of the system to a strong
pulse excitation is calculated. It is shown that radiative decay in graphene
differs from that of conventional two-dimensional electron systems both
quantitatively and qualitatively. Possible applications of the predicted
effects for generation of terahertz radiation are discussed.


title:
Hard X-ray colours of Neutron Star and Black Hole Low Mass X-ray
  Binaries with INTEGRAL

abstract:
  The X-ray spectra of Low Mass X-ray Binaries (LMXB) can change on short
time-scales, making it difficult to follow their spectral characteristics in
detail through model fitting. Colour-colour (C-C) diagrams are therefore often
used as alternative, model independent, tools to study the spectral variability
of these sources. The INTEGRAL mission, with its high sensitivity, large field
of view and good angular resolution, is well suited to study the hard X-ray
properties of LMXBs. In particular the ISGRI imager on board of INTEGRAL allows
the regular monitoring of the sources in the less frequently studied domain
above 20 keV. In this proceeding, C-C diagrams have been made with data from
the INTEGRAL public archive; a search is made for systematic differences in the
C-C diagrams between black hole candidates (BH) and neutron stars (NS) in LMXBs
using a moments analysis method.


title: Chern numbers and the geometry of partial flag manifolds

abstract:
  We calculate the Chern classes and Chern numbers for the natural almost
Hermitian structures of the partial flag manifolds F_n=SU(n+2)/S(U(n)\times
U(1)\times U(1)). For all n>1 there are two invariant complex algebraic
structures, which arise from the projectivizations of the holomorphic tangent
and cotangent bundles of complex projective spaces. The projectivization of the
cotangent bundle is the twistor space of a Grassmannian considered as a
quaternionic K\"ahler manifold. There is also an invariant nearly K\"ahler
structure, because F_n is a 3-symmetric space. We explain the relations between
the different structures and their Chern classes, and we prove that F_n is not
geometrically formal.


title: Phase diagram of a two-component Fermi gas with resonant interactions

abstract:
  The pairing of fermions is at the heart of superconductivity and
superfluidity. The recent experimental realization of strongly interacting
atomic Fermi gases has opened a new, controllable way to study novel forms of
pairing and superfluidity. A major controversial issue has been the stability
of superfluidity against an imbalance between the two spin components when the
fermions interact resonantly. Here we present the phase diagram of a
spin-polarized Fermi gas of $^6$Li atoms at unitarity, mapping out the
superfluid phase versus temperature and density imbalance. Using tomographic
techniques, we reveal spatial discontinuities in the spin polarization, the
signature of a first-order superfluid-to-normal phase transition, which
disappears at a tricritical point where the nature of the phase transition
changes from first-order to second-order. At zero temperature, there is a
quantum phase transition from a fully-paired superfluid to a
partially-polarized normal gas. These observations and the implementation of an
in situ ideal gas thermometer provide quantitative tests of theoretical
calculations on the stability of resonant superfluidity.


title:
Emerging complexity in a simple model of the mechanical behaviour of
  rocks

abstract:
  We propose a mechanical model for the behaviour of rocks based on progressive
damage at the elementary scale and elastic interaction. It allows us to
simulate several experimental observations: mechanical behaviour ranging from
brittle to ductile, fractal structure of the damage, powerlaw distribution of
the damage avalanches. These macroscopic properties are not incorporated at the
elementary scale, but are the results of the interaction between elements. This
emerging complexity permits us to consider the strain rock process as a complex
system characterized by non-linear dynamics.


title: (Co)homology of quantum complete intersections

abstract:
  We construct a minimal projective bimodule resolution for every finite
dimensional quantum complete intersection of codimension two. Then we use this
resolution to compute both the Hochschild cohomology and homology for such an
algebra. In particular, we show that the cohomology vanishes in high degrees,
while the homology is always nonzero.


title:
Recent results on (anti)nucleus and (anti)hyperon production in
  nucleus-nucleus collisions at CERN SPS energies

abstract:
  The NA49 experiment has collected comprehensive data on particle production
in nucleus-nucleus collisions over the whole SPS beam energies range, the
critical energy domain where the expected phase transition to a deconfined
phase is expected to occur. The latest results from Pb+Pb collisions between
20$A$ GeV and 158$A$ GeV on baryon stopping and light nuclei production as well
as those for strange hyperons are presented.
  The measured data on $p$, $\bar{p}$, $\Lambda$, $\bar{\Lambda}$, $\Xi^-$ and
$\bar{\Xi}^+$ production were used to evaluate the rapidity distributions of
net-baryons at SPS energies and to compare with the results from the AGS and
the RHIC for central Pb+Pb (Au+Au) collisions.
  The dependence of the yield ratios and the inverse slope parameter of the
$m_t$ spectra on the collision energy and centrality, and the mass number of
the produced nuclei $^3He$, $t$, $d$ and $\bar{d}$ are discussed within
coalescence and statistical approaches. Analysis of the total multiplicity
exhibits remarkable agreement between the measured yield for $^3He$ and those
predicted by the statistical hadronization model.
  In addition, new results on $\Lambda$ and $\bar{\Lambda}$ as well as $\Xi^-$
production in minimum bias Pb+Pb reactions at 40$A$ GeV and 158$A$ GeV and
central C+C, Si+Si and Pb+Pb collisions are presented. The system size
dependence of the yields of these hyperons was analysed to determine the
evolution of strangeness enhancement relative to elementary p+p collisions.


title:
On the origin of ultra high energy cosmic rays: Subluminal and
  superluminal relativistic shocks

abstract:
  The flux of Ultra High Energy Cosmic Rays (UHECRs) at $E>10^{18.5}$ eV is
believed to arise in plasma shock environments in extragalactic sources. In
this paper, we present a systematic study of particle acceleration by
relativistic shocks, in particular concerning the dependence on bulk Lorentz
factor and the angle between the magnetic field and the shockflow. For the
first time, simulation results of super- and subluminal shocks with boost
factors up to $\Gamma=1000$ are investigated and compared systematically. While
superluminal shocks are shown to be inefficient at the highest energies
($E>10^{18.5}$ eV), subluminal shocks may provide particles up to $10^{21}$ eV,
limited only by the Hillas-criterion. For the subluminal case, we find that
mildly relativistic shocks, thought to occur in jets of Active Galactic Nuclei
(AGN, $\Gamma\sim 10-30$) yield energy spectra of $dN/dE\sim E^{-2}$. Highly
relativistic shocks expected in Gamma Ray Bursts (GRBs, $100<\Gamma<1000$), on
the other hand, have spectra as flat as $E^{-1.5}$. The model results are
compared to the measured flux of Cosmic Rays at the highest energies and it is
shown that, while AGN spectra are well-suited, GRB spectra are too flat to
explain the observed flux. The first evidence of a correlation between the
Cosmic Ray flux above $5.7\cdot 10^{10}$ GeV and the distribution of AGN by
Auger are explained by the model. Neutrino production is expected in GRBs,
either in mildly or highly relativistic shocks and although these sources are
excluded as the principle origin of UHECRs, superluminal shocks in particular
may be observable via neutrino and photon fluxes, rather than as protons.


title: Erratum: algebraic spin liquid as the mother of many competing orders

abstract:
  We correct an error in our paper Phys. Rev. B 72, 104404 (2005)
[cond-mat/0502215]. We show that a particular fermion bilinear is not related
to the other ``competing orders'' of the algebraic spin liquid, and does not
possess their slowly decaying correlations. For the square lattice staggered
flux spin liquid (equivalently, d-wave RVB state), this observable corresponds
to the uniform spin chirality.


title:
Comparison of quantization of charge transport in periodic and open
  pumps

abstract:
  We compare the charges transported in two systems, a spatially periodic and
an open quantum pump, both depending periodically and adiabatically on time.
The charge transported in a cycle was computed by Thouless, respectively by
Buttiker et al. in the two cases. We show that the results agree in the limit
where the two physical situations become the same, i.e., that of a large open
pump.


title:
Query Evaluation in P2P Systems of Taxonomy-based Sources: Algorithms,
  Complexity, and Optimizations

abstract:
  In this study, we address the problem of answering queries over a
peer-to-peer system of taxonomy-based sources. A taxonomy states subsumption
relationships between negation-free DNF formulas on terms and negation-free
conjunctions of terms. To the end of laying the foundations of our study, we
first consider the centralized case, deriving the complexity of the decision
problem and of query evaluation. We conclude by presenting an algorithm that is
efficient in data complexity and is based on hypergraphs. More expressive forms
of taxonomies are also investigated, which however lead to intractability. We
then move to the distributed case, and introduce a logical model of a network
of taxonomy-based sources. On such network, a distributed version of the
centralized algorithm is then presented, based on a message passing paradigm,
and its correctness is proved. We finally discuss optimization issues, and
relate our work to the literature.


title:
Detecting Higgs bosons in the bb decay channel using forward proton
  tagging at the LHC

abstract:
  A detailed study is presented of the search for Higgs bosons in the b-decay
channel in the central exclusive production process at the LHC. We present
results for proton tagging detectors at both 220m and 420m around ATLAS or CMS.
We consider two benchmark scenarios; a Standard Model (SM) Higgs boson and the
m_h^{max} scenario of the Minimal Supersymmetric Standard Model (MSSM).
Detector acceptance, smearing and event trigger strategies are considered. We
find that the SM Higgs will be challenging to observe in the b-jet channel
without improvements to the currently proposed experimental configuration, but
a neutral scalar MSSM Higgs Boson could be observable in the b-jet channel with
a significance of 3 sigma or greater within three years of data taking at all
luminosities between 2 x 10^{33} cm^{-2} s^{-1} and 10^{34} cm^{-2} s^{-1}, and
at 5 sigma or greater after three years in certain scenarios.


title: Modeling the consequences of tongue surgery on tongue mobility

abstract:
  This paper presents the current achievements of a long term project aiming at
predicting and assessing the impact of tongue and mouth floor surgery on tongue
mobility. The ultimate objective of this project is the design of a software
with which surgeons should be able (1) to design a 3D biomechanical model of
the tongue and of the mouth floor that matches the anatomical characteristics
of each patient specific oral cavity, (2) to simulate the anatomical changes
induced by the surgery and the possible reconstruction, and (3) to
quantitatively predict and assess the consequences of these anatomical changes
on tongue mobility and speech production after surgery.


title:
Time-dependent density-functional theory for ultrafast interband
  excitations

abstract:
  We formulate a time-dependent density functional theory (TDDFT) in terms of
the density matrix to study ultrafast phenomena in semiconductor structures. A
system of equations for the density matrix components, which is equivalent to
the time-dependent Kohn-Sham equation, is derived. From this we obtain a TDDFT
version of the semiconductor Bloch equations, where the electronic many-body
effects are taken into account in principle exactly. As an example, we study
the optical response of a three-dimensional two-band insulator to an external
short-time pulsed laser field. We show that the optical absorption spectrum
acquires excitonic features when the exchange-correlation potential contains a
$1/q^{2}$ Coulomb singularity. A qualitative comparison of the TDDFT optical
absorption spectra with the corresponding results obtained within the
Hartree-Fock approximation is made.


title:
Determination of nuclear parton distribution functions and their
  uncertainties at next-to-leading order

abstract:
  Nuclear parton distribution functions (NPDFs) are determined by global
analyses of experimental data on structure-function ratios F_2^A/F_2^{A'} and
Drell-Yan cross-section ratios \sigma_{DY}^A/\sigma_{DY}^{A'}. The analyses are
done in the leading order (LO) and next-to-leading order (NLO) of running
coupling constant \alpha_s. Uncertainties of the NPDFs are estimated in both LO
and NLO for finding possible NLO improvement. Valence-quark distributions are
well determined, and antiquark distributions are also determined at x<0.1.
However, the antiquark distributions have large uncertainties at x>0.2. Gluon
modifications cannot be fixed at this stage. Although the advantage of the NLO
analysis, in comparison with the LO one, is generally the sensitivity to the
gluon distributions, gluon uncertainties are almost the same in the LO and NLO.
It is because current scaling-violation data are not accurate enough to
determine precise nuclear gluon distributions. Modifications of the PDFs in the
deuteron are also discussed by including data on the proton-deuteron ratio
F_2^D/F_2^p in the analysis. A code is provided for calculating the NPDFs and
their uncertainties at given x and Q^2 in the LO and NLO.


title: Random even graphs

abstract:
  We study a random even subgraph of a finite graph $G$ with a general
edge-weight $p\in(0,1)$. We demonstrate how it may be obtained from a certain
random-cluster measure on $G$, and we propose a sampling algorithm based on
coupling from the past. A random even subgraph of a planar lattice undergoes a
phase transition at the parameter-value $\frac 12 \pc$, where $\pc$ is the
critical point of the $q=2$ random-cluster model on the dual lattice. The
properties of such a graph are discussed, and are related to Schramm--L\"owner
evolutions (SLE).


title: The Tate conjecture over finite fields (AIM talk)

abstract:
  These are my notes for a talk at the The Tate Conjecture workshop at the
American Institute of Mathematics in Palo Alto, CA, July 23--July 27, 2007,
somewhat revised and expanded. The intent of the talk was to review what is
known and to suggest directions for research. v2: Revised expanded (24 pages).


title: Supersymmetry breaking made easy, viable, and generic

abstract:
  The kind of supersymmetry that can be discovered at the LHC must be very much
flavor-blind, which used to require very special intelligently designed models
of supersymmetry breaking. This led to the pessimism for some in the community
that it is not likely for the LHC to discover supersymmetry. I point out that
this is not so, because a garden-variety supersymmetric theories actually can
do this job.


title:
Computer aided planning and navigation for orbito-zygomatic
  reconstruction

abstract:
  This paper suggests a full protocol of Computer Aided Surgery as previously
recommended in literature addressing the challenging task of primary or
secondary reconstruction of orbito-zygomatic dislocation. First, on a
specifically developed planning software, the best zygoma reduction and orbital
boundaries reconstruction to achieve skeletal symmetry are determined. This
treatment plan is then transferred to the 3D Navigation Systems within the
operating room. After patient's anatomy registration to his preoperative CT
scan data, the navigation system allows zygomatic guiding to its planned
reduced location and bone orbital volume restoration control. The feasibility
of this technique was checked in 3 patients with major orbito-zygomatic
deformities. Preliminary clinical results are presented.


title:
Radiation from relativistic jets in blazars and the efficient
  dissipation of their bulk energy via photon breeding

abstract:
  High-energy photons propagating in the magnetised medium with large velocity
gradients can mediate energy and momentum exchange. Conversion of these photons
into electron-positron pairs in the field of soft photons with the consequent
isotropization and emission of new high-energy photons by Compton scattering
can lead to the runaway cascade of the high-energy photons and
electron-positron pairs fed by the bulk energy of the flow. This is the essence
of the photon breeding mechanism. We study the problem of high-energy emission
of relativistic jets in blazars via photon breeding mechanism using 2D
ballistic model for the jet with the detailed treatment of particle propagation
and interactions. The gamma-ray background of similar energy density as
observed at Earth is sufficient to trigger the photon breeding. As a result, a
jet can convert up to 80 per cent of its total power into radiation. Photon
breeding produces a population of high-energy pairs and predicts the spectra in
agreement with observations of blazars (e.g. the blazar sequence). It also
decelerates the jet at subparsec scales and induces the transversal gradient of
the Lorentz factor which reconcile the discrepancy between the high Doppler
factors determined from the spectra of TeV blazars and the low apparent
velocities observed at VLBI scales. The broad angular distribution of radiation
predicted by the mechanism reconciles the observed statistics and luminosity
ratio of FR I and BL Lac objects with the large Lorentz factors of the jets as
well as explains the high level of the TeV emission in the radio galaxy M87.
(abridged)


title: Determinants of (generalised) Catalan numbers

abstract:
  We show that recent determinant evaluations involving Catalan numbers and
generalisations thereof have most convenient explanations by combining the
Lindstr\"om-Gessel-Viennot theorem on non-intersecting lattice paths with a
simple determinant lemma from [Manuscripta Math. 69 (1990), 173-202]. This
approach leads also naturally to extensions and generalisations.


title: Network model of human language

abstract:
  The phenomenon of human language is widely studied from various points of
view. It is interesting not only for social scientists, antropologists or
philosophers, but also for those, interesting in the network dynamics. In
several recent papers word web, or language as a graph has been investigated.
  In this paper I revise recent studies of syntactical word web. I present a
model of growing network in which such processes as node addition, edge
rewiring and new link creation are taken into account. I argue, that this model
is a satisfactory minimal model explaining measured data.


title:
Modified perturbation theory for pair production and decay of
  fundamental unstable particles

abstract:
  We construct an asymptotic expansion in powers of the coupling constant
directly of the cross-section for pair production and decay of fundamental
unstable particles. The resonant and kinematic singularities arising in the
expansion we treat in the sense of distributions. This mode allows us to
transform formally divergent integrals into absolutely convergent ones with
keeping the asymptotic property of the expansion. The appropriate procedure is
elaborated up to an arbitrary order of the expansion. The peculiarity of
application of the procedure in the threshold region is analysed. The scheme of
the calculations within the NNLO approximation is explicitly discussed.


title:
NBursts: Simultaneous Extraction of Internal Kinematics and Parametrized
  SFH from Integrated Light Spectra

abstract:
  We present a novel approach for simultaneous extraction of stellar population
parameters and internal kinematics from the spectra integrated along a line of
sight. We fit a template spectrum into an observed one in a pixel space using a
non-linear $\chi^2$ minimization in the multidimensional parameter space,
including characteristics of the line-of-sight velocity distribution (LOSVD)
and parametrized star formation history (SFH). Our technique has been applied
to IFU and multi-object spectroscopy of low-luminosity early type galaxies.


title:
Recent results from the NA48 experiment at CERN: CP violation and CKM
  parameter Vus

abstract:
  Several recent results from the NA48 experiment are presented: a measurement
$|\eta_{+-}|$, search for CP violating phenomena in $K^\pm\to3\pi$ decays, and
a measurement of $|V_{us}|$.


title: Epidemic Size in the Sis Model of Endemic Infec- Tions

abstract:
  We study the Susceptible-Infected-Susceptible model of the spread of an
endemic infection. We calculate an exact expression for the mean number of
transmissions for all values of the population and the infectivity. We derive
the large-N asymptotic behavior for the infectivitiy below, above, and in the
critical region. We obtain an analytical expression for the probability
distribution of the number of transmissions, n, in the critical region. We show
that this distribution has a $n^3/2$ singularity for small n and decays
exponentially for large n. The exponent decreases with the distance from
threshold, diverging to infinity far below and approaching zero far above.


title: Coherent tunneling by adiabatic passage in an optical waveguide system

abstract:
  We report on the first experimental demonstration of light transfer in an
engineered triple-well optical waveguide structure which provides a classic
analogue of Coherent Tunnelling by Adiabatic Passage (CTAP) recently proposed
for coherent transport in space of neutral atoms or electrons among
tunneling-coupled optical traps or quantum wells [A.D. Greentree et al., Phys.
Rev. B 70, 235317 (2004); K. Eckert et al., Phys. Rev. A 70, 023606 (2004)].
The direct visualization of CTAP wavepacket dynamics enabled by our simple
optical system clearly shows that in the counterintuitive passage scheme light
waves tunnel between the two outer wells without appreciable excitation of the
middle well.


title:
Monte Carlo study of coaxially gated CNTFETs: capacitive effects and
  dynamic performance

abstract:
  Carbon Nanotube (CNT) appears as a promising candidate to shrink field-effect
transistors (FET) to the nanometer scale. Extensive experimental works have
been performed recently to develop the appropriate technology and to explore DC
characteristics of carbon nanotube field effect transistor (CNTFET). In this
work, we present results of Monte Carlo simulation of a coaxially gated CNTFET
including electron-phonon scattering. Our purpose is to present the intrinsic
transport properties of such material through the evaluation of electron
mean-free-path. To highlight the potential of high performance level of CNTFET,
we then perform a study of DC characteristics and of the impact of capacitive
effects. Finally, we compare the performance of CNTFET with that of Si nanowire
MOSFET.


title: Access to Stellar Population Models in the Virtual Observatory

abstract:
  A great effort is being made by the international Virtual Observatory
community to build tools ready to be used by scientists. Presently, providing
access to theoretical spectra in general, and synthetic spectra of galaxies in
particular, is a matter of current interest in the Virtual Observatory. Several
ways of accessing such spectra are available. We present two of them for
accessing PEGASE.HR evolutionary synthesis models: HTTP-access to a limited
number of parameters using Simple Spectral Access Protocol (SSAP), and
full-featured WEB-service based access using Common Execution Architecture
(CEA).


title: Avalanche Photo-Detection for High Data Rate Applications

abstract:
  Avalanche photo detection is commonly used in applications which require
single photon sensitivity. We examine the limits of using avalanche photo
diodes (APD) for characterising photon statistics at high data rates. To
identify the regime of linear APD operation we employ a ps-pulsed diode laser
with variable repetition rates between 0.5MHz and 80MHz. We modify the mean
optical power of the coherent pulses by applying different levels of
well-calibrated attenuation. The linearity at high repetition rates is limited
by the APD dead time and a non-linear response arises at higher photon-numbers
due to multiphoton events. Assuming Poissonian input light statistics we
ascertain the effective mean photon-number of the incident light with high
accuracy. Time multiplexed detectors (TMD) allow to accomplish photon- number
resolution by photon chopping. This detection setup extends the linear response
function to higher photon-numbers and statistical methods may be used to
compensate for non-linearity. We investigated this effect, compare it to the
single APD case and show the validity of the convolution treatment in the TMD
data analysis.


title:
Splitting of Andreev levels in a Josephson junction by spin-orbit
  coupling

abstract:
  We consider the effect of spin-orbit coupling on the energy levels of a
single-channel Josephson junction below the superconducting gap. We investigate
quantitatively the level splitting arising from the combined effect of
spin-orbit coupling and the time-reversal symmetry breaking by the phase
difference between the superconductors. Using the scattering matrix approach we
establish a simple connection between the quantum mechanical time delay matrix
and the effective Hamiltonian for the level splitting. As an application we
calculate the distribution of level splittings for an ensemble of chaotic
Josephson junctions. The distribution falls off as a power law for large
splittings, unlike the exponentially decaying splitting distribution given by
the Wigner surmise -- which applies for normal chaotic quantum dots with
spin-orbit coupling in the case that the time-reversal symmetry breaking is due
to a magnetic field.


title: The subdiffusive target problem: Survival probability

abstract:
  The asymptotic survival probability of a spherical target in the presence of
a single subdiffusive trap or surrounded by a sea of subdiffusive traps in a
continuous Euclidean medium is calculated. In one and two dimensions the
survival probability of the target in the presence of a single trap decays to
zero as a power law and as a power law with logarithmic correction,
respectively. The target is thus reached with certainty, but it takes the trap
an infinite time on average to do so. In three dimensions a single trap may
never reach the target and so the survival probability is finite and, in fact,
does not depend on whether the traps move diffusively or subdiffusively. When
the target is surrounded by a sea of traps, on the other hand, its survival
probability decays as a stretched exponential in all dimensions (with a
logarithmic correction in the exponent for $d=2$). A trap will therefore reach
the target with certainty, and will do so in a finite time. These results may
be directly related to enzyme binding kinetics on DNA in the crowded cellular
environment.


title: Residue Classes Having Tardy Totients

abstract:
  We show, in an effective way, that there exists a sequence of congruence
classes $a_k\pmod {m_k}$ such that the minimal solution $n=n_k$ of the
congruence $\phi(n)\equiv a_k\pmod {m_k}$ exists and satisfies $\log n_k/\log
m_k\to\infty $ as $k\to\infty$. Here, $\phi(n)$ is the Euler function. This
answers a question raised in \cite{FS}. We also show that every congruence
class containing an even integer contains infinitely many values of the
Carmichael function $\lambda(n)$ and the least such $n$ satisfies $n\ll
m^{13}$.


title: Joint resummation for slepton pair production at hadron colliders

abstract:
  We present a precision calculation of the transverse-momentum and
invariant-mass distributions for supersymmetric particle pair production at
hadron colliders, focusing on Drell-Yan like slepton pair and slepton-sneutrino
associated production at the CERN Large Hadron Collider. We implement the joint
resummation formalism at the next-to-leading logarithmic accuracy with a
process-independent Sudakov form factor, thus ensuring a universal description
of soft-gluon emission, and consistently match the obtained result with the
pure perturbative result at the first order in the strong coupling constant,
i.e. at O(alpha_s). We also implement three different recent parameterizations
of non-perturbative effects. Numerically, we give predictions for ~e_R ~e_R^*
production and compare the resummed cross section with the perturbative result.
The dependence on unphysical scales is found to be reduced, and
non-perturbative contributions remain small.


title:
Giant magnetoelectric effect induced by intrinsic surface stress in
  ferroic nanorods

abstract:
  The general approach for the consideration of the magnetoelectric effects in
ferroic nanorods is proposed in the framework of the phenomenological theory.
The intrinsic surface stress, magneto- and electrostriction as well as
piezoelectric and piezomagnetic effects are included into the free energy. The
intrinsic surface stress under the curved nanoparticle surface is shown to play
an important role in the shift of ferroelectric and ferromagnetic transition
temperatures and built-in magnetic and electric fields appearance, which are
inversely proportional to the nanorod radius. We consider the case of quadratic
and linear magnetoelectric coupling coefficients. The linear coupling
coefficient is radius independent, whereas the quadratic ones include terms
inversely proportional to the nanorod radius and thus strongly increase with
decrease of the radius. The predicted giant relative dielectric tunability in
the vicinity of ferromagnetic and ferroelectric phase transition points induced
by quadratic magnetoelectric coupling increases by 2-50 times. The quadratic
magnetoelectric coupling dramatically changes the phase diagrams of ferroic
nanorods when the radius decreases. In particular the second order phase
transition may become a first one, the triple point state characterized by
continuous set of order parameters appears at zero external electric and
magnetic fields and the tricritical points appear under external fields.


title: M-Theory Brane Deformations

abstract:
  Using the techniques developed by Lunin and Maldacena we calaculate the
supergravity solutions of membranes and fivebranes in the presence of a
background C field. All the distinct possible C-field configurations are
explored. Decoupling limits for these branes are then described that preserve
the deformation leading to families of M-theory brane deformation duals. The
decoupled geometry is then explored using probe brane techniques and brane
thermodynamics.


title:
Heavily obscured AGN with BeppoSAX, INTEGRAL, SWIFT, XMM and Chandra:
  prospects for Simbol-X

abstract:
  According to the latest versions of synthesis modeling of the Cosmic X-ray
Background, Compton Thick AGN should represent ~50% of the total absorbed AGN
population. However, despite their importance in the cosmological context, only
a few dozens of Compton Thick AGN have been found and studied so far. We will
briefly review this topic and discuss the improvement in this field offered by
the Simbol-X mission with its leap in sensitivity (E>10 keV) of more than a
factor 500 with respect to previous X-ray missions.


title:
Monte Carlo study of the evaporation/condensation transition on
  different Ising lattices

abstract:
  In 2002 Biskup et al. [Europhys. Lett. 60, 21 (2002)] sketched a rigorous
proof for the behavior of the 2D Ising lattice gas, at a finite volume and a
fixed excess \delta M of particles (spins) above the ambient gas density
(spontaneous magnetisation). By identifying a dimensionless parameter \Delta
(\delta M) and a universal constant \Delta_c, they showed in the limit of large
system sizes that for \Delta < \Delta_c the excess is absorbed in the
background (``evaporated'' system), while for \Delta > \Delta_c a droplet of
the dense phase occurs (``condensed'' system).
  To check the applicability of the analytical results to much smaller,
practically accessible system sizes, we performed several Monte Carlo
simulations for the 2D Ising model with nearest-neighbour couplings on a square
lattice at fixed magnetisation M. Thereby, we measured the largest minority
droplet, corresponding to the condensed phase, at various system sizes (L=40,
>..., 640). With analytic values for for the spontaneous magnetisation m_0, the
susceptibility \chi and the Wulff interfacial free energy density \tau_W for
the infinite system, we were able to determine \lambda numerically in very good
agreement with the theoretical prediction.
  Furthermore, we did simulations for the spin-1/2 Ising model on a triangular
lattice and with next-nearest-neighbour couplings on a square lattice. Again,
finding a very good agreement with the analytic formula, we demonstrate the
universal aspects of the theory with respect to the underlying lattice. For the
case of the next-nearest-neighbour model, where \tau_W is unknown analytically,
we present different methods to obtain it numerically by fitting to the
distribution of the magnetisation density P(m).


title: Multiple interactions and AGK rules in pQCD

abstract:
  We review some aspects of multiple interactions in High Energy QCD; we
discuss in particular AGK rules and present some results concerning multiple
interactions in the context of jet production.


title:
Deep MMT Transit Survey of the Open Cluster M37 I: Observations and
  Cluster Parameters

abstract:
  We have conducted a deep ($15 \la r \la 23$), 20 night survey for transiting
planets in the intermediate age open cluster M37 (NGC 2099) using the Megacam
wide-field mosaic CCD camera on the 6.5m Multiple Mirror Telescope (MMT). In
this paper we describe the observations and data reduction procedures for the
survey and analyze the stellar content and dynamical state of the cluster. By
combining high resolution spectroscopy with existing $BVI_{C}K_{S}$ and new
$gri$ color magnitude diagrams we determine the fundamental cluster parameters:
$t = 485 \pm 28$ Myr without overshooting ($t = 550 \pm 30 {\rm Myr}$ with
overshooting), $E(B-V) = 0.227 \pm 0.038$, $(m-M)_{V} = 11.57 \pm 0.13$ and
$[M/H] = +0.045 \pm 0.044$ which are in good agreement with, though more
precise than, previous measurements. We determine the mass function down to
$0.3 M_{\odot}$ and use this to estimate the total cluster mass of $3640 \pm
170 M_{\odot}$.


title:
Model for Vortex Pinning in a Two-Dimensional Inhomogeneous d-wave
  Superconductor

abstract:
  We study a model for the pinning of vortices in a two-dimensional,
inhomogeneous, Type-II superconductor in its mixed state. The model is based on
a Ginzburg-Landau (GL) free energy functional whose coefficients are determined
by the mean-field transition temperature T_{c0} and the zero-temperature
penetration depth \lambda(0). We find that if (i) T_{c0} and \lambda(0) are
functions of position, and (ii) \lambda^2(0) is proportional to T_{c0}^y, with
y greater than 0, then the vortices tend to be pinned where T_{c0}, and hence
the magnitude of the superconducting order parameter \Delta, are large. This
behavior is in contrast to the usual picture of pinning in Type-II
superconductors, where pinning occurs in the small-gap regions. We also compute
the local density of states of a model BCS Hamiltonian with d-wave symmetry, in
which the pairing field is obtained from Monte Carlo simulations of a GL free
energy. Several features observed in scanning tunneling spectroscopy
measurements on YBa_2Cu_3O_{6+x} and Bi_2Sr_2CaCu_2O_{8+x} are well reproduced
by our model: far from the cores, the local density of states spectrum has a
small gap and sharp coherence peaks, while near the cores it has a larger gap
with low, broad peaks. Additionally, also in agreement with experiment, the
spectrum near the core does not exhibit a zero-energy peak which is, however,
observed in other theoretical studies.


title:
VLT / Infrared Integral Field Spectrometer Observations of Molecular
  Hydrogen Lines in the Knots in the Planetary Nebula NGC 7293 (the Helix
  Nebula)

abstract:
  Knots are commonly found in nearby planetary nebulae (PNe) and star forming
regions. Within PNe, knots are often found to be associated with the brightest
parts of the nebulae and understanding the physics involved in knots may reveal
the processes dominating in PNe. As one of the closest PNe, the Helix Nebula
(NGC 7293) is an ideal target to study such small-scale (~300 AU) structures.
We have obtained infrared integral spectroscopy of a comet-shaped knot in the
Helix Nebula using SINFONI on the Very Large Telescope at high spatial
resolution (50-125 mas). With spatially resolved 2 micron spectra, we find that
the H2 rotational temperature within the cometary knots is uniform. The
rotational-vibrational temperature of the cometary knot (situated in the
innermost region of the nebula, 2.5 arcmin away from the central star), is 1800
K, higher than the temperature seen in the outer regions (5-6 arcmin from the
central star) of the nebula (900 K), showing that the excitation temperature
varies across the nebula. The obtained intensities are reasonably well fitted
with 27 km s-1 C-type shock model. This ambient gas velocity is slightly higher
than the observed [HeII] wind velocity of 13 km s-1. The gas excitation can
also be reproduced with a PDR (photo dominant region) model, but this requires
an order of magnitude higher UV radiation. Both models have limitations,
highlighting the need for models that treats both hydrodynamical physics and
the PDR.


title: Cosmic Ray Physics with ACORDE at LHC

abstract:
  The use of large underground high-energy physics experiments, for comic ray
studies, have been used, in the past, at CERN, in order to measure, precisely,
the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV.
ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and,
together with other ALICE apparatus, will provide precise information on cosmic
rays with primary energies around 10^15 - 10^17 eV. This paper reviews the main
detector features, the present status, commissioning and integration with other
apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.


title:
Relation between full traces of Green functions for initial and Darboux
  transformed Dirac problems

abstract:
  We establish the relation between full traces of the Green functions for some
initial and the Darboux transformed one-dimensional two component Dirac
problems with the most general form of potential. The result is used to check
the completeness of set of wave functions obtained by the Darboux
transformation of the eigenfunctions set for the initial Dirac problem with
some typical boundary conditions.


title: Bose-Einstein Condensation of an Ytterbium Isotope

abstract:
  We report the observation of a Bose Einstein condensate in a bosonic isotope
of ytterbium (170Yb). More than 10^6 atoms are trapped in a crossed optical
dipole trap and cooled by evaporation. Condensates of approximately 10^4 atoms
have been obtained. From an expansion of the condensate, we have extracted the
scattering length a=3.6(9) nm.


title:
Brane Solutions in Time Dependent Backgrounds in D = 11 Supergravity and
  in Type II String Theories

abstract:
  We obtain explicit time dependent brane solutions in M-theory as well as in
string theory by solving the reduced equations of motion (which follow from
11-d supergravity) for a class of brane solutions in curved backgrounds. The
behaviour of our solutions in both asymptotic and near-horizon limits are
studied. It is shown that our time dependent solutions serve as explicit
examples of branes in singular, cosmological backgrounds. In some special cases
the asymptotic and the boundary AdS solutions can be identified as Milne X R^n
spacetime.


title: 3D SPH simulations of grain growth in protoplanetary disks

abstract:
  We present the first results of the treatment of grain growth in our 3D,
two-fluid (gas+dust) SPH code describing protoplanetary disks. We implement a
scheme able to reproduce the variation of grain sizes caused by a variety of
physical processes and test it with the analytical expression of grain growth
given by Stepinski & Valageas (1997) in simulations of a typical T Tauri disk
around a one solar mass star. The results are in agreement with a turbulent
growing process and validate the method. We are now able to simulate the grain
growth process in a protoplanetary disk given by a more realistic physical
description, currently under development. We discuss the implications of the
combined effect of grain growth and dust vertical settling and radial migration
on subsequent planetesimal formation.


title: Binding of Nucleobases with Single-Walled Carbon Nanotubes

abstract:
  We have calculated the binding energy of various nucleobases (guanine (G),
adenine (A), thymine (T) and cytosine (C)) with (5,5) single-walled carbon
nanotubes (SWNTs) using ab-initio Hartre-Fock method (HF) together with force
field calculations. The gas phase binding energies follow the sequence G $>$ A
$>$ T $>$ C. We show that main contribution to binding energy comes from
van-der Wall (vdW) interaction between nanotube and nucleobases. We compare
these results with the interaction of nucleobases with graphene. We show that
the binding energy of bases with SWNTs is much lower than the graphene but the
sequence remains same. When we include the effect of solvation energy
(Poisson-Boltzman (PB) solver at HF level), the binding energy follow the
sequence G $>$ T $>$ A $>$ C $>$, which explains the experiment\cite{zheng}
that oligonucleotides made of thymine bases are more effective in dispersing
the SWNT in aqueous solution as compared to poly (A) and poly (C). We also
demonstrate experimentally that there is differential binding affinity of
nucleobases with the single-walled carbon nanotubes (SWNTs) by directly
measuring the binding strength using isothermal titration (micro) calorimetry.
The binding sequence of the nucleobases varies as thymine (T) $>$ adenine (A)
$>$ cytosine (C), in agreement with our calculation.


title:
The Distance of the First Overtone RR Lyrae Variables in the MACHO LMC
  Database: A New Method to Correct for the Effects of Crowding

abstract:
  Previous studies have indicated that many of the RR Lyrae variables in the
LMC have properties similar to the ones in the Galactic globular cluster M3.
Assuming that the M3 RR Lyrae variables follow the same relationships among
period, temperature, amplitude and Fourier phase parameter phi31 as their LMC
counterparts, we have used the M3 phi31-logP relation to identify the M3-like
unevolved first overtone RR Lyrae variables in 16 fields near the LMC bar. The
temperatures of these variables were calculated from the M3 logP-logTe relation
so that the extinction could be derived for each star separately. Since blended
stars have lower amplitudes for a given period, the period amplitude relation
should be a useful tool for identifying which stars are affected by crowding.
We find that the low amplitude stars are brighter. We remove them from the
sample and derive an LMC distance modulus 18.49+/-0.11.


title:
Intermittency and Universality in Fully-Developed Inviscid and
  Weakly-Compressible Turbulent Flows

abstract:
  We performed high resolution numerical simulations of homogenous and
isotropic compressible turbulence, with an average 3D Mach number close to 0.3.
We study the statistical properties of intermittency for velocity, density and
entropy. For the velocity field, which is the primary quantity that can be
compared to the isotropic incompressible case, we find no statistical
differences in its behavior in the inertial range due either to the slight
compressibility or to the different dissipative mechanism. For the density
field, we find evidence of ``front-like'' structures, although no shocks are
produced by the simulation.


title: Spectra of primordial fluctuations in two-perfect-fluid regular bounces

abstract:
  We introduce analytic solutions for a class of two components bouncing
models, where the bounce is triggered by a negative energy density perfect
fluid. The equation of state of the two components are constant in time, but
otherwise unrelated. By numerically integrating regular equations for scalar
cosmological perturbations, we find that the (would be) growing mode of the
Newtonian potential before the bounce never matches with the the growing mode
in the expanding stage. For the particular case of a negative energy density
component with a stiff equation of state we give a detailed analytic study,
which is in complete agreement with the numerical results. We also perform
analytic and numerical calculations for long wavelength tensor perturbations,
obtaining that, in most cases of interest, the tensor spectral index is
independent of the negative energy fluid and given by the spectral index of the
growing mode in the contracting stage. We compare our results with previous
investigations in the literature.


title: Low-temperature phonon thermal conductivity of cuprate single crystals

abstract:
  The effect of sample size and surface roughness on the phonon thermal
conductivity $\kappa_p$ of Nd$_2$CuO$_4$ single crystals was studied down to 50
mK. At 0.5 K, $\kappa_p$ is proportional to $\sqrt{A}$, where $A$ is the
cross-sectional area of the sample. This demonstrates that $\kappa_p$ is
dominated by boundary scattering below 0.5 K or so. However, the expected $T^3$
dependence of $\kappa_p$ is not observed down to 50 mK. Upon roughing the
surfaces, the $T^3$ dependence is restored, showing that departures from $T^3$
are due to specular reflection of phonons off the mirror-like sample surfaces.
We propose an empirical power law fit, to $\kappa_p \sim T^{\alpha}$ (where
$\alpha < 3$) in cuprate single crystals. Using this method, we show that
recent thermal conductivity studies of Zn doping in YBa$_2$Cu$_3$O$_y$
re-affirm the universal heat conductivity of d-wave quasiparticles at $T \to
0$.


title:
Spitzer/IRS Observations of Seyfert 1.8s and 1.9s: A Comparison with
  Seyfert 1s and Seyfert 2s

abstract:
  We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and
1.9 galaxies over the 5-38 um region. We compare the spectral characteristics
of this sample to those of 58 Seyfert 1 and Seyfert 2 galaxies from the Spitzer
archives. An analysis of the spectral shapes, the silicate 10 um feature and
the emission line fluxes have enabled us to characterize the mid-IR properties
of Seyfert 1.8/1.9s. We find that the equivalent widths of the 10 um silicate
feature are generally weak in all Seyfert galaxies, as previously reported by
several studies. The few Seyfert galaxies in this sample that show deep 10 um
silicate absorption features are highly inclined and/or merging galaxies. It is
likely that these absorption features originate primarily in the dusty
interstellar medium of the host galaxy rather than in a dusty torus on parsec
scales close to the central engine. We find that the equivalent width of the
polycyclic aromatic hydrocarbon (PAH) band at 6.2 um correlates strongly with
the 20-30 um spectral index. Either of these quantities are good indicators of
the amount of starburst contribution to the mid-IR spectra. The spectra of
Seyfert 1.8 and 1.9s are dominated by these starburst features, similar to most
Seyfert 2s. They show strong PAH bands and a strong red continuum toward 30 um.
The strengths of the high-ionization forbidden narrow emission lines [O IV]
25.89 um, [Ne III] 15.56 um and [Ne V] 14.32 um relative to [Ne II] 12.81 um
are weaker in Seyfert 1.8/1.9s and Seyfert 2s as compared to Seyfert 1s. The
weakness of high-ionization lines in Seyfert 1.8-1.9s is suggestive of
intrinsically weak active galactic nuclei (AGN) continua, and/or stronger star
formation activity leading to enhanced [Ne II]. We discuss the implications of
these observational results in the context of the Unified Model of AGN.


title:
Improved actions and lattice coarsening effects in MCRG studies in SU(2)
  LGT

abstract:
  We study decimation procedures and effective (improved) actions in the
framework of Monte Carlo Renormalization Group (MCRG). Particular attention is
paid to matching the form of the effective action to the decimation procedure
parameters. Using the static quark-antiquark potential in SU(2) LGT we probe
different distance scales and find that an effective action containing multiple
group representations is capable of reproducing long distance physics well. In
particular, appropriate matching results in the practical elimination of the
coarsening/fining effect of the lattice spacing under decimation. The short
distance regime of the effective theory is also studied. We next carry out
studies of effective actions involving both multiple representations and loops
beyond the single plaquette towards determining an improved action good over a
wide length scale regime.


title: Formation and evolution of galactic spheroids by mergers

abstract:
  Galactic spheroids can form as a result of galaxy interactions and mergers of
disks. Detailed analyses of the photometric properties, the intrinsic orbital
structure, the line-of-sight velocity distributions and the kinemetry of
simulated merger remnants, which depend critically on the geometry and the gas
content of the interacting progenitors, indicate that low and intermediate mass
rotating ellipticals can form from mergers of disks. The masses and
metallicities of all massive ellipticals and the kinematics of some massive
non-rotating ellipticals cannot be explained by binary mergers. Thus these
galaxies might have formed in a different way.


title: Computing a pyramid partition generating function with dimer shuffling

abstract:
  We verify a recent conjecture of Kenyon/Szendroi, arXiv:0705.3419, by
computing the generating function for pyramid partitions. Pyramid partitions
are closely related to Aztec Diamonds; their generating function turns out to
be the partition function for the Donaldson--Thomas theory of a non-commutative
resolution of the conifold singularity {x1x2 -x3x4 = 0}. The proof does not
require algebraic geometry; it uses a modified version of the domino shuffling
algorithm of Elkies, Kuperberg, Larsen and Propp.


title: Chirally symmetric but confining dense and cold matter

abstract:
  The folklore tradition about the QCD phase diagram is that at the chiral
restoration phase transition at finite density hadrons are deconfined and there
appears the quark matter. We address this question within the only known
exactly solvable confining and chirally symmetric model. It is postulated
within this model that there exists linear Coulomb-like confining interaction.
The chiral symmetry breaking and the quark Green function are obtained from the
Schwinger-Dyson (gap) equation while the color-singlet meson spectrum results
from the Bethe-Salpeter equation. We solve this model at T=0 and finite
chemical potential $\mu$ and obtain a clear chiral restoration phase transition
at the critical value \mu_{cr}. Below this value the spectrum is similar to the
previously obtained one at \mu = 0. At \mu > \mu_{cr} the quarks are still
confined and the physical spectrum consists of bound states which are arranged
into a complete set of exact chiral multiplets. This explicitly demonstrates
that a chirally symmetric matter consisting of confined but chirally symmetric
hadrons at finite chemical potential is also possible in QCD. If so, there must
be nontrivial implications for astrophysics.


title: Vibrational energy transfer in ultracold molecule - molecule collisions

abstract:
  We present a rigorous study of vibrational relaxation in p-H2 + p-H2
collisions at cold and ultracold temperatures and identify an efficient
mechanism of ro-vibrational energy transfer. If the colliding molecules are in
different rotational and vibrational levels, the internal energy may be
transferred between the molecules through an extremely state-selective process
involving simultaneous conservation of internal energy and total rotational
angular momentum. The same transition in collisions of distinguishable
molecules corresponds to the rotational energy transfer from one vibrational
state of the colliding molecules to another.


title: The martingale problem for a class of stable-like processes

abstract:
  Let $\alpha\in (0,2)$ and consider the operator $$L f(x) =\int
[f(x+h)-f(x)-1_{(|h|\leq 1)} \nabla f(x)\cdot h] \frac{A(x,h)}{|h|^{d+\alpha}}
dh, $$ where the $\nabla f(x)\cdot h$ term is omitted if $\alpha<1$. We
consider the martingale problem corresponding to the operator $L$ and under
mild conditions on the function $A$ prove that there exists a unique solution.


title: Progress in nuclear data for accelerator applications in Europe

abstract:
  This contribution essentially will be divided into two parts: First, a brief
overview on topical accelerator applications in Europe, a selection of the
European 6th framework accelerator and ADS programs will be given, second the
emphasis will be put on selected nuclear data required for designing facilities
planned or even under construction. In this second part the progress on nuclear
data in the EU FP6 Integrated Project IP-EUROTRANS (specifically NUDATRA) is
summarized. For proton-induced reactions in the energy range of 200-2500 MeV
experimental data and model comparisons are shown on total and double
differential production cross sections of H- and He-isotopes and intermediate
mass fragments.


title:
Josephson dynamics for coupled polariton modes under the atom-field
  interaction in the cavity

abstract:
  We consider a new approach to the problem of Bose-Einstein condensation (BEC)
of polaritons for atom-field interaction under the strong coupling regime in
the cavity. We investigate the dynamics of two macroscopically populated
polariton modes corresponding to the upper and lower branch energy states
coupled via Kerr-like nonlinearity of atomic medium. We found out the
dispersion relations for new type of collective excitations in the system under
consideration. Various temporal regimes like linear (nonlinear) Josephson
transition and/or Rabi oscillations, macroscopic quantum self-trapping (MQST)
dynamics for population imbalance of polariton modes are predicted. We also
examine the switching properties for time-averaged population imbalance
depending on initial conditions, effective nonlinear parameter of atomic medium
and kinetic energy of low-branch polaritons.


title: The Period Changes of the Cepheid RT Aurigae

abstract:
  Observations of the light curve for the 3.7-day Cepheid RT Aur both before
and since 1980 indicate that the variable is undergoing an overall period
increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as
implied by all observations prior to 1980. Superposed on the star's O-C
variations is a sinusoidal trend that cannot be attributed to random
fluctuations in pulsation period. Rather, it appears to arise from light travel
time effects in a binary system. The derived orbital period for the system is P
= 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from
the O-C residuals differ from those indicated by existing radial velocity data.
The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x
10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued
monitoring of the brightness and radial velocity changes in the Cepheid are
necessary to confirm the long-term trend and to provide data for a proper
spectroscopic solution to the orbit.


title: Wave Excitation in Disks Around Rotating Magnetic Stars

abstract:
  The accretion disk around a rotating magnetic star (neutron star, white dwarf
or T Tauri star) is subjected to periodic vertical magnetic forces from the
star, with the forcing frequency equal to the stellar spin frequency or twice
the spin frequency. This gives rise bending waves in the disk that may
influence the variabilities of the system. We study the excitation, propagation
and dissipation of these waves using a hydrodynamical model coupled with a
generic model description of the magnetic forces. The $m=1$ bending waves are
excited at the Lindblad/vertical resonance, and propagate either to larger
radii or inward toward the corotation resonance where dissipation takes place.
While the resonant torque is negligible compared to the accretion torque, the
wave nevertheless may reach appreciable amplitude and can cause or modulate
flux variabilities from the system. We discuss applications of our result to
the observed quasi-periodic oscillations from various systems, in particular
neutron star low-mass X-ray binaries.


title: X-winds in Action

abstract:
  The interaction of accretion disks with the magnetospheres of young stars can
produce X-winds and funnel flows. With the assumption of axial symmetry and
steady state flow, the problem can be formulated in terms of quantities that
are conserved along streamlines, such as the Bernoulli integral (BI), plus a
partial differential equation (PDE), called the Grad-Shafranov equation (GSE),
that governs the distribution of streamlines in the meridional plane. The GSE
plus BI yields a PDE of mixed type, elliptic before critical surfaces where the
flow speed equals certain characteristic wave speeds are crossed and hyperbolic
afterward. The computational difficulties are exacerbated by the locations of
the critical surfaces not being known in advance. To overcome these obstacles,
we consider a variational principle by which the GSE can be attacked by
extremizing an action integral, with all other conserved quantities of the
problem explicitly included as part of the overall formulation. To simplify
actual applications we adopt the cold limit of a negligibly small ratio of the
sound speed to the speed of Keplerian rotation in the disk where the X-wind is
launched. We also ignore the obstructing effects of any magnetic fields that
might thread a disk approximated to be infinitesimally thin. We then introduce
trial functions with adjustable coefficients to minimize the variations that
give the GSE. We tabulate the resulting coefficients so that other workers can
have analytic forms to reconstruct X-wind solutions for various astronomical,
cosmochemical, and meteoritical applications.


title:
A survey of SiO 5-4 emission towards outflows from massive young stellar
  objects

abstract:
  Results are presented of a survey of SiO 5-4 emission observed with the James
Clerk Maxwell Telescope (JCMT) towards a sample of outflows from massive young
stellar objects. The sample is drawn from a single-distance study by Ridge &
Moore. In a sample of 12 sources, the 5-4 line was detected in 5, a detection
rate of 42 per cent. This detection rate is higher than that found for a sample
of low-luminosity outflow sources, although for sources of comparable
luminosity, it is in good agreement with the results of a previous survey of
high luminosity sources. For most of the detected sources, the 5-4 emission is
compact or slightly extended along the direction of the outflow. NGC6334I shows
a clear bipolar flow in the 5-4 line. Additional data were obtained for
W3-IRS5, AFGL5142 and W75N for the 2-1 transition of SiO using the
Berkeley-Illinois-Maryland Association (BIMA) millimetre interferometer. There
is broad agreement between the appearance of the SiO emission in both lines,
though there are some minor differences. The 2-1 emission in AFGL5142 is
resolved into two outflow lobes which are spatially coincident on the sky, in
good agreement with previous observations. In general the SiO emission is
clearly associated with the outflow. The primary indicator of SiO 5-4
detectability is the outflow velocity, i.e. the presence of SiO is an indicator
of a high velocity outflow. This result is consistent with the existence of a
critical shock velocity required to disrupt dust grains and subsequent SiO
formation in post-shock gas. There is also weak evidence that higher luminosity
sources and denser outflows are more likely to be detected.


title:
Revealing the Nature of Asymmetric Planetary Nebulae through Abundance
  Analysis

abstract:
  The correlations between planetary nebula (PN) morphology and the nature of
their progenitors are explored by examining homogeneous PN samples in the
Galaxy and the Magellanic Clouds. We selected PNe with reliable abundances from
spectral analysis, and whose morphology is known, and compared the abundances
of the element at variance with stellar evolution with the final yields of
Asymptotic Giant Branch (AGB) stellar models. We found that most asymmetric PNe
derive from the evolution of massive AGB stars both in the Galactic disk and
the Magellanic Clouds.


title: The ambiguity-free four-dimensional Lorentz-breaking Chern-Simons action

abstract:
  The four dimensional Lorentz-breaking finite and determined Chern-Simons like
action is generated as a one loop perturbative correction via an appropriate
Lorentz-breaking coupling of the gauge field with the spinor field. Unlike the
known schemes of calculations, within this scheme this term is found to be
regularization independent.


title: Derived Algebraic Geometry IV: Deformation Theory

abstract:
  In this paper, we prove some foundational results on the deformation theory
of E-infinity ring spectra.


title:
The fundamental form of a homogeneous Lagrangian in two independent
  variables

abstract:
  We construct, for a homogeneous Lagrangian of arbitrary order in two
independent variables, a differential 2-form with the property that it is
closed precisely when the Lagrangian is null. This is similar to the property
of the `fundamental Lepage equivalent' associated with first-order Lagrangians
defined on jets of sections of a fibred manifold.


title: Short Timescale Coronal Variability in Capella

abstract:
  We analyze 205 ks of imaging data of the active binary, Capella, obtained
with the Chandra High Resolution Camera Imager (HRC-I) to determine whether
Capella shows any variability at timescales < 50 ks. We find that a clear
signal for variability is present for timescales < 20 ks, and that the light
curves show evidence for excess fluctuation over that expected from a purely
Poisson process. This overdispersion is consistent with variability at the 2-7%
level, and suggests that the coronae on the binary components of Capella are
composed of low-density plasma and low-lying loops.


title: Transition from small to large world in growing networks

abstract:
  We examine the global organization of growing networks in which a new vertex
is attached to already existing ones with a probability depending on their age.
We find that the network is infinite- or finite-dimensional depending on
whether the attachment probability decays slower or faster than $(age)^{-1}$.
The network becomes one-dimensional when the attachment probability decays
faster than $(age)^{-2}$. We describe structural characteristics of these
phases and transitions between them.

categories: cond-mat.stat-mech cs.NI math-ph math.MP physics.soc-ph


title: Integrable lattice equations and their growth properties

abstract:
  In this paper we investigate the integrability of two-dimensional partial
difference equations using the newly developed techniques of study of the
degree of the iterates. We show that while for generic, nonintegrable
equations, the degree grows exponentially fast, for integrable lattice
equations the degree growth is polynomial. The growth criterion is used in
order to obtain the integrable deautonomisations of the equations examined. In
the case of linearisable lattice equations we show that the degree growth is
slower than in the case of equations integrable through Inverse Scattering
Transform techniques.


title:
Remarks on Dynamical Dark Energy Measured by the Conformal Age of the
  Universe

abstract:
  We elaborate on a model of conformal dark energy (dynamical dark energy
measured by the conformal age of the universe) recently proposed in [H. Wei and
R.G. Cai, arXiv:0708.0884] where the present-day dark energy density was taken
to be $\rho_q \equiv 3 \alpha^2 m_P^2/\eta^2$, where $\eta$ is the conformal
time and $\alpha$ is a numerical constant. In the absence of an interaction
between the ordinary matter and dark energy field $q$, the model may be
adjusted to the present values of the dark energy density fraction $\Omega\Z{q}
\simeq 0.73$ and the equation of state parameter $w\Z{q} < -0.78$, if the
numerical constant $\alpha$ takes a reasonably large value, $\alpha\gtrsim
2.6$. However, in the presence of a nontrivial gravitational coupling of
$q$-field to matter, say $\widetilde{Q}$, the model may be adjusted to the
values $\Omega\Z{q}\simeq 0.73$ and $w\Z{q}\simeq -1$, even if $\alpha\sim
{\cal O}(1)$, given that the present value of $\widetilde{Q}$ is large. Unlike
for the model in [R.G. Cai, arXiv:0707.4049], the bound $\Omega\Z{q} <0.1$
during big bang nucleosynthesis (BBN) may be satisfied for almost any value of
$\alpha$. Here we discuss some other limitations of this proposal as a viable
dark energy model. The model draws some parallels with the holographic dark
energy; we also briefly comment on the latter model.


title:
Efficient electron heating in relativistic shocks and gamma ray burst
  afterglow

abstract:
  Electrons in shocks are efficiently energized due to the cross-shock
potential, which develops because of differential deflection of electrons and
ions by the magnetic field in the shock front. The electron energization is
necessarily accompanied by scattering and thermalization. The mechanism is
efficient in both magnetized and non-magnetized relativistic electron-ion
shocks. It is proposed that the synchrotron emission from the heated electrons
in a layer of strongly enhanced magnetic field is responsible for gamma ray
burst afterglows.