title: Pretty clean monomial ideals and linear quotients

abstract:
  We study basic properties of monomial ideals with linear quotients. It is
shown that if the monomial ideal $I$ has linear quotients, then the squarefree
part of $I$ and each component of $I$ as well as $\mm I$ have linear quotients,
where $\mm$ is the graded maximal ideal of the polynomial ring. As an analogy
to the Rearrangement Lemma of Bj\"orner and Wachs we also show that for a
monomial ideal with linear quotients the admissible order of the generators can
be chosen degree increasingly.
  As a generalization of the facet ideal of a forest, we define monomial ideals
of forest type and show that they are pretty clean. This result recovers a
recent result of Tuly and Villarreal about the shellability of a clutter with
the free vertex property. As another consequence of this result we show that if
$I$ is a monomial ideal of forest type, then Stanley's conjecture on Stanley
decomposition holds for $S/I$. We also show that a clutter is totally balanced
if and only if it has the free vertex property.


title: Gamma-ray background: a review

abstract:
  The gamma-ray background is still a subject under great debate.
  All phenomena in the universe emitting gamma-rays can contribute directly as
diffuse emission or as an isotropic component from unresolved point sources.
The question of the origin of the extragalactic component cannot be answered
without determining the galactic emission. To discuss in detail all models
resulting in gamma-ray background contributions is far beyond the scope of this
paper. Therefore the focus will be on recent publications on the extragalactic
high energy (>100 MeV) part of the gamma-ray background.


title:
Effect of connecting wires on the decoherence due to electron-electron
  interaction in a metallic ring

abstract:
  We consider the weak localization in a ring connected to reservoirs through
leads of finite length and submitted to a magnetic field. The effect of
decoherence due to electron-electron interaction on the harmonics of AAS
oscillations is studied, and more specifically the effect of the leads. Two
results are obtained for short and long leads regimes. The scale at which the
crossover occurs is discussed. The long leads regime is shown to be more
realistic experimentally.


title:
Renormalization Group and Asymptotic Spin--Charge separation for Chiral
  Luttinger liquids

abstract:
  The phenomenon of Spin-Charge separation in non-Fermi liquids is well
understood only in certain solvable d=1 fermionic systems. In this paper we
furnish the first example of asymptotic Spin-Charge separation in a d=1 non
solvable model. This goal is achieved using Renormalization Group approach
combined with Ward-Identities and Schwinger-Dyson equations, corrected by the
presence of a bandwidth cut-offs. Such methods, contrary to bosonization, could
be in principle applied also to lattice or higher dimensional systems.


title:
Anderson Localization of Bogolyubov Quasiparticles in Interacting
  Bose-Einstein Condensates

abstract:
  We study the Anderson localization of Bogolyubov quasiparticles in an
interacting Bose-Einstein condensate (with healing length \xi) subjected to a
random potential (with finite correlation length \sigma_R). We derive
analytically the Lyapunov exponent as a function of the quasiparticle momentum
k and we study the localization maximum k_{max}. For 1D speckle potentials, we
find that k_{max} is proportional to 1/\xi when \xi is much larger than
\sigma_R while k_{max} is proportional to 1/\sigma_R when \xi is much smaller
than \sigma_R, and that the localization is strongest when \xi is of the order
of \sigma_R. Numerical calculations support our analysis and our estimates
indicate that the localization of the Bogolyubov quasiparticles is accessible
in current experiments with ultracold atoms.


title:
Spectroscopic analysis of two peculiar emission line stars: RJHA 49 and
  SS73 21

abstract:
  Aims: To investigate the spectra and the evolutionary stages of two peculiar
emission-line stars: RJHA 49 and SS73 21. Methods: We used low and high
resolution optical data. Line identifications and measurements were performed
for several features in their spectra. Results: For each object, we have
derived the extinction and the excitation temperature from a set of [Fe II]
lines, and the electron density from [N II] lines. For RJHA 49, no detailed
spectroscopic study was done so far. Regarding SS73 21, our low resolution
spectrum have confirmed the main characteristics found in previous works. On
the other side, from our high resolution data, we have found that the Halpha
line presents a double-peak, in contrast with the suggestion in the literature
that it should reveal a P-Cygni profile. Surprisingly, we found a few He I
transitions resembling P-Cygni profiles (e.g. He I 5876), directly suggesting
that mass loss is active in SS73 21. We also discussed the nature of these two
objects based on the data obtained. Although the evolutionary status of SS73 21
seems well established from previous studies (a proto-planetary nebula), the
situation for RJHA 49 is not so clear mainly due to its unknown distance.
However, from the strength of [N II] 5754 relative to [O I] 6300, the
possibility of RJHA 49 being a LBV object is reduced, and a B[e]-supergiant or
a proto-planetary nebula status is more plausible.


title: A non-homogeneous orbit of a diagonal subgroup

abstract:
  Let G=SL(n,R) with n>5. We construct examples of lattices Gamma of G,
subgroup A of the diagonal group and points x in G/Gamma such that the closure
of the orbit Ax is not homogeneous but does not factors through the action of a
one-parameter non-unipotent group. This contradicts a conjecture of Margulis.


title: Covering a line segment with variable radius discs

abstract:
  The paper addresses the problem of locating sensors with a circular field of
view so that a given line segment is under full surveillance, which is termed
as the Disc Covering Problem on a Line. The cost of each sensor includes a
fixed component, and a variable component that is proportional to the
field-of-view area. When only one type of sensor or, in general, one type of
disc, is available, then a simple polynomial algorithm solves the problem. When
there are different types of sensors in terms of fixed and variable costs, the
problem becomes NP-hard. A branch-and-bound algorithm as well as an efficient
heuristic are developed. The heuristic very often obtains the optimal solution
as shown in extensive computational testing.


title: Measurement of the tau- --> K- pi0 nu_tau Branching Fraction

abstract:
  A measurement of the tau- --> K- pi0 nu_tau branching fraction has been made
using 230.2 fb-1 of data recorded by the BABAR detector at the PEP-II e+ e-
collider, located at the Stanford Linear Accelerator Center (SLAC), at a center
of mass energy sqrt{s} close to 10.58 GeV. We measure BF(tau- --> K- pi0
nu_tau) = (0.416 +/- 0.003 (stat) +/- 0.018 (syst)) %.


title: The Odderon at RHIC and LHC

abstract:
  The Odderon remains an elusive object, 33 years after its invention. The
Odderon is now a fundamental object in QCD and CGC and it has to be found
experimentally if QCD and CGC are right. In the present talk, we show how to
find it at RHIC and LHC. The most spectacular signature of the Odderon is the
predicted difference between the differential cross-sections for proton-proton
and antiproton-proton at high s and moderate t. This experiment can be done by
using the STAR detector at RHIC and by combining these future data with the
already present UA4/2 data. The Odderon could also be found by ATLAS experiment
at LHC by performing a high-precision measurement of the real part of the
hadron elastic scattering amplitude at small t.


title: On the Quantum Kolmogorov Complexity of Classical Strings

abstract:
  We show that classical and quantum Kolmogorov complexity of binary strings
agree up to an additive constant. Both complexities are defined as the minimal
length of any (classical resp. quantum) computer program that outputs the
corresponding string.
  It follows that quantum complexity is an extension of classical complexity to
the domain of quantum states. This is true even if we allow a small
probabilistic error in the quantum computer's output. We outline a mathematical
proof of this statement, based on an inequality for outputs of quantum
operations and a classical program for the simulation of a universal quantum
computer.


title: Swift observations of high-redshift radio-loud quasars

abstract:
  We report on Swift observations of four z>2 radio-loud quasars (0212+735,
0537-286, 0836+710, and 2149-307), classified as blazars. The sources,
well-known emitters at soft-medium X-rays, were detected at >5sigma with the
BAT experiment in 15-150 keV. No flux variability was detected within the XRT
and BAT exposures, with the exception of 0836+710 which shows an increase of a
factor 4 of the 15-150 keV flux on a timescale of one month. The 0.3-10 keV
spectra are well fitted by power law models, with rather hard continua (photon
indices Gamma_XRT ~1.3-1.5); similarly, the 15-150 keV spectra are described by
power laws with Gamma_BAT ~1.3-1.8. The XRT data exhibit spectral curvature,
which can be modeled either in terms of excess absorption along the line of
sight, or a downward-curved broken power law. In the former case, if the excess
N_H is at the rest-frame of the source, columns of N_H^z=(0.3-6)x10^22 cm^-2
are measured. Modeling of the SEDs of the four quasars shows that the emission
at the higher frequencies, >~ 10^16 Hz, is dominated by the jet, while the
steep optical-to-UV continua, observed with the UVOT, can be attributed to
thermal emission from the accretion disk. The disk luminosity is between 1% and
10% the jet power, similar to other powerful blazars.


title: Robust Hypothesis Testing with a Relative Entropy Tolerance

abstract:
  This paper considers the design of a minimax test for two hypotheses where
the actual probability densities of the observations are located in
neighborhoods obtained by placing a bound on the relative entropy between
actual and nominal densities. The minimax problem admits a saddle point which
is characterized. The robust test applies a nonlinear transformation which
flattens the nominal likelihood ratio in the vicinity of one. Results are
illustrated by considering the transmission of binary data in the presence of
additive noise.


title: Constructing simply laced Lie algebras from extremal elements

abstract:
  For any finite graph Gamma and any field K of characteristic unequal to 2 we
construct an algebraic variety X over K whose K-points parameterise K-Lie
algebras generated by extremal elements, corresponding to the vertices of the
graph, with prescribed commutation relations, corresponding to the non-edges.
After that, we study the case where Gamma is a connected, simply laced Dynkin
diagram of finite or affine type. We prove that X is then an affine space, and
that all points in an open dense subset of X parameterise Lie algebras
isomorphic to a single fixed Lie algebra. If Gamma is of affine type, then this
fixed Lie algebra is the split finite-dimensional simple Lie algebra
corresponding to the associated finite-type Dynkin diagram. This gives a new
construction of these Lie algebras, in which they come together with
interesting degenerations, corresponding to points outside the open dense
subset. Our results may prove useful for recognising these Lie algebras.


title: Formation of Protoplanets from Massive Planetesimals in Binary Systems

abstract:
  More than half of stars reside in binary or multiple star systems and many
planets have been found in binary systems. From theoretical point of view,
however, whether or not the planetary formation proceeds in a binary system is
a very complex problem, because secular perturbation from the companion star
can easily stir up the eccentricity of the planetesimals and cause
high-velocity, destructive collisions between planetesimals. Early stage of
planetary formation process in binary systems has been studied by restricted
three-body approach with gas drag and it is commonly accepted that accretion of
planetesimals can proceed due to orbital phasing by gas drag. However, the gas
drag becomes less effective as the planetesimals become massive. Therefore it
is still uncertain whether the collision velocity remains small and planetary
accretion can proceed, once the planetesimals become massive. We performed {\it
N}-body simulations of planetary formation in binary systems starting from
massive planetesimals whose size is about 100-500 km. We found that the
eccentricity vectors of planetesimals quickly converge to the forced
eccentricity due to the coupling of the perturbation of the companion and the
mutual interaction of planetesimals if the initial disk model is sufficiently
wide in radial distribution. This convergence decreases the collision velocity
and as a result accretion can proceed much in the same way as in isolated
systems. The basic processes of the planetary formation, such as runaway growth
and oligarchic growth and final configuration of the protoplanets are
essentially the same in binary systems and single star systems, at least in the
late stage where the effect of gas drag is small.


title: Superbosonization of invariant random matrix ensembles

abstract:
  Superbosonization is a new variant of the method of commuting and
anti-commuting variables as used in studying random matrix models of disordered
and chaotic quantum systems. We here give a concise mathematical exposition of
the key formulas of superbosonization. Conceived by analogy with the
bosonization technique for Dirac fermions, the new method differs from the
traditional one in that the superbosonization field is dual to the usual
Hubbard-Stratonovich field. The present paper addresses invariant random matrix
ensembles with symmetry group U(n), O(n), or USp(n), giving precise definitions
and conditions of validity in each case. The method is illustrated at the
example of Wegner's n-orbital model. Superbosonization promises to become a
powerful tool for investigating the universality of spectral correlation
functions for a broad class of random matrix ensembles of non-Gaussian and/or
non-invariant type.


title: Strong saturation absorption imaging of dense clouds of ultracold atoms

abstract:
  We report on a far above saturation absorption imaging technique to
investigate the characteristics of dense packets of ultracold atoms. The
transparency of the cloud is controlled by the incident light intensity as a
result of the non-linear response of the atoms to the probe beam. We detail our
experimental procedure to calibrate the imaging system for reliable
quantitative measurements, and demonstrate the use of this technique to extract
the profile and its spatial extent of an optically thick atomic cloud.


title: Fog and Dew Collection Projects in Croatia

abstract:
  The present paper discusses the fog and dew water collection in Croatia.
Zavizan, the highest meteorological station in Croatia(1594m) is chosen for
collecting of fog water with a standard fog collector (SFC). The highest daily
collection rate was 27.8 L / m2. The highest daily collection rate in days
without rain was 19.1 l/m2. Dew is also a noticeable source of water,
especially during the drier summer season. Dew condensers in Croatia have been
installed on the Adriatic coast (Zadar) and islands Vis and Bisevo. We report
and discuss the data collected since 2003. In the small Bisevo island, a
special roof has been designed to improve the formation and collection of dew
on a house. Data from April 2005 will be presented and discussed.


title: Superbosonization formula and its application to random matrix theory

abstract:
  Starting from Gaussian random matrix models we derive a new supermatrix field
theory model. In contrast to the conventional non-linear sigma models, the new
model is applicable for any range of correlations of the elements of the random
matrices. We clarify the domain of integration for the supermatrices, and give
a demonstration of how the model works by calculating the density of states for
an ensemble of almost diagonal matrices. It is also shown how one can reduce
the supermatrix model to the conventional sigma model.


title:
Photoactivation at a clinical LINAC: The 197Au(gamma,n)196Au reaction
  slightly above threshold

abstract:
  The properties of a clinical LINAC are investigated for a study of
photoactivation cross sections slightly above the neutron threshold. As an
example, the photoactivation of a tiny amount of gold by the
197Au(gamma,n)196Au reaction has been measured. The derived photon intensity is
at least comparable to conventional and widely used photon sources. In
combination with its extremely stable operation, a clinical LINAC ensures that
photoactivation studies can be performed for a wide number of targets with very
limited beamtime.


title:
Instrumented Collective Learning Situations (ICLS): the Gap between
  Theoretical Research and Observed Practices

abstract:
  According to socio-constructivism approach, collective situations are
promoted to favor learning in classroom, at a distance or in a blended
educational context. So, many Information and Communication Technologies (ICT)
are provided to teachers but there are no clear studies about the way they are
used and perceived. Our research is based on the hypothesis that practices of
educational actors (instructional designers and tutors) are far away from
theoretical results of research in education technologies. In this paper, we
consider a precise kind of situation: Instrumented Collective Learning
Situations (ICLS). By a survey on 13 fields in higher education in France,
Switzerland and Canada, we present how ICLS are designed and how teachers used
them. Conclusions give an indication on the gap between the way information
technologies are prescribed and the way they are actually used and perceived by
teachers.


title:
X-ray Observations and Infrared Identification of the Transient 7.8 s
  X-ray Binary Pulsar XTE J1829-098

abstract:
  XMM-Newton and Chandra observations of the transient 7.8 s pulsar XTE
J1829-098 are used to characterize its pulse shape and spectrum, and to
facilitate a search for an optical or infrared counterpart. In outburst, the
absorbed, hard X-ray spectrum with Gamma = 0.76+/-0.13 and N_H = (6.0+/-0.6) x
10^{22} cm^{-2} is typical of X-ray binary pulsars. The precise Chandra
localization in a faint state leads to the identification of a probable
infrared counterpart at R.A. = 18h29m43.98s, decl. = -09o51'23.0" (J2000.0)
with magnitudes K=12.7, H=13.9, I>21.9, and R>23.2. If this is a highly
reddened O or B star, we estimate a distance of 10 kpc, at which the maximum
observed X-ray luminosity is 2x10^{36} ergs s^{-1}, typical of Be X-ray
transients or wind-fed systems. The minimum observed luminosity is
3x10^{32}(d/10 kpc)^2 ergs s^{-1}. We cannot rule out the possibility that the
companion is a red giant. The two known X-ray outbursts of XTE J1829-098 are
separated by ~1.3 yr, which may be the orbital period or a multiple of it, with
the neutron star in an eccentric orbit. We also studied a late M-giant
long-period variable that we found only 9" from the X-ray position. It has a
pulsation period of ~1.5 yr, but is not the companion of the X-ray source.


title: Anomalous dimensions of leading twist conformal operators

abstract:
  We extend and develop a method for perturbative calculations of anomalous
dimensions and mixing matrices of leading twist conformal primary operators in
conformal field theories. Such operators lie on the unitarity bound and hence
are conserved (irreducible) in the free theory. The technique relies on the
known pattern of breaking of the irreducibility conditions in the interacting
theory. We relate the divergence of the conformal operators via the field
equations to their descendants involving an extra field and accompanied by an
extra power of the coupling constant. The ratio of the two-point functions of
descendants and of their primaries determines the anomalous dimension, allowing
us to gain an order of perturbation theory. We demonstrate the efficiency of
the formalism on the lowest-order analysis of anomalous dimensions and mixing
matrices which is required for two-loop calculations of the former. We compare
these results to another method based on anomalous conformal Ward identities
and constraints from the conformal algebra. It also permits to gain a
perturbative order in computations of mixing matrices. We show the complete
equivalence of both approaches.


title: Excitation Spectra of Correlated Lattice Bosons in a Confining Trap

abstract:
  We consider ultracold bosonic atoms in an optical lattice with an external
trapping potential. To study the excitation energies of the resulting
Bose-Hubbard model, we develop a method based on a time-dependent
generalization of the Gutzwiller ansatz. We calculate the excitations of the
homogeneous system both in insulating and superfluid regime, concentrating
particularly on those near the superfluid-Mott insulator boundary. Low-lying
excitation energies in presence of a static harmonic trap are obtained using
this method and compared with the homogeneous case. Further, we explore the
dynamics of the center of mass and the breathing mode in response to
time-dependent perturbations of the trap.


title: Map of metastable states for thin circular magnetic nano-cylinders

abstract:
  Nano-magnetic systems of artificially shaped ferromagnetic islands, recently
became a popular subject due to their current and potential applications in
spintronics, magneto-photonics and superconductivity. When the island size is
close to the exchange length of magnetic material (around 15 nm), its magnetic
structure becomes markedly different. It determines both static and dynamic
magnetic properties of elements, but strongly depends on their shape and size.
Here we map this dependence for circular cylindrical islands of a few exchange
lengths in size. We outline the region of metastability of "C"-type magnetic
states, proving that they are indeed genuine and not a result of pinning on
particle imperfections. A way to create the smallest particles with guaranteed
magnetic vortex state at zero field becomes evident. It is expected that the
map will help focus the efforts in planning of experiments and devices.


title:
The physics of randomness and regularities for languages (lifetimes,
  family trees, and the second languages); in terms of random matrices

abstract:
  The physics of randomness and regularities for languages (mother tongues) and
their lifetimes and family trees and for the second languages are studied in
terms of two opposite processes; random multiplicative noise [1], and
fragmentation [2], where the original model is given in the matrix format. We
start with a random initial world, and come out with the regularities, which
mimic various empirical data [3] for the present languages.


title: The Hilbert space operator formalism within dynamical reduction models

abstract:
  Unlike standard quantum mechanics, dynamical reduction models assign no
particular a priori status to `measurement processes', `apparata', and
`observables', nor self-adjoint operators and positive operator valued measures
enter the postulates defining these models. In this paper, we show why and how
the Hilbert-space operator formalism, which standard quantum mechanics
postulates, can be derived from the fundamental evolution equation of dynamical
reduction models. Far from having any special ontological meaning, we show that
within the dynamical reduction context the operator formalism is just a compact
and convenient way to express the statistical properties of the outcomes of
experiments.


title: The BeppoSAX WFC X-ray source catalogue

abstract:
  We present the catalogue of X-ray sources detected by the two Wide Field
Cameras (WFCs) in complete observations on board BeppoSAX during its 6 years of
operational lifetime, between April 1996 and April 2002. The BeppoSAX WFCs were
coded mask instruments sensitive in the 2-28 keV energy band with a 40x40
square degree fields of view, pointing in opposite directions and
perpendicularly to the BeppoSAX Narrow Field Instruments (NFI). The WFCs were
usually operated simultaneously to NFI observations, each lasting up to several
days. WFCs observed thus the entire sky several times with a typical
sensitivity of 2 to 10 mCrab. A systematic analysis of all WFC observations in
the BeppoSAX archive has been carried out using the latest post-mission release
of the WFC analysis software and calibrations. The catalogue includes 253
distinct sources, obtained from a total sample of 8253 WFC detections. We
describe the basic statistical properties of the sample and present a six-year
history of two celestial calibration X-ray sources.


title: Fermion masses, Leptogenesis and Supersymmetric SO(10) Unification

abstract:
  Current neutrino oscillation data indicate the existence of two large lepton
mixing angles, while Kobayashi-Maskawa matrix elements are all small. Here we
show how supersymmetric SO(10) with extra chiral singlets can easily reconcile
large lepton mixing angles with small quark mixing angles within the framework
of the successful Fritzsch ansatz. Moreover we show how this is fully
consistent with the thermal leptogenesis scenario, avoiding the so-called
gravitino problem. A sizeable asymmetry can be generated at relatively low
scales. We present our results in terms of the leptonic CP violation parameter
that characterizes neutrino oscillations.


title:
Diffusive and ballistic current spin-polarization in magnetron-sputtered
  L1o-ordered epitaxial FePt

abstract:
  We report on the structural, magnetic, and electron transport properties of a
L1o-ordered epitaxial iron-platinum alloy layer fabricated by
magnetron-sputtering on a MgO(001) substrate. The film studied displayed a long
range chemical order parameter of S~0.90, and hence has a very strong
perpendicular magnetic anisotropy. In the diffusive electron transport regime,
for temperatures ranging from 2 K to 258 K, we found hysteresis in the
magnetoresistance mainly due to electron scattering from magnetic domain walls.
At 2 K, we observed an overall domain wall magnetoresistance of about 0.5 %. By
evaluating the spin current asymmetry alpha = sigma_up / sigma_down, we were
able to estimate the diffusive spin current polarization. At all temperatures
ranging from 2 K to 258 K, we found a diffusive spin current polarization of >
80%. To study the ballistic transport regime, we have performed point-contact
Andreev-reflection measurements at 4.2 K. We obtained a value for the ballistic
current spin polarization of ~42% (which compares very well with that of a
polycrystalline thin film of elemental Fe). We attribute the discrepancy to a
difference in the characteristic scattering times for oppositely spin-polarized
electrons, such scattering times influencing the diffusive but not the
ballistic current spin polarization.


title: Measuring gluon shadowing with prompt photons at RHIC and LHC

abstract:
  The possibility to observe the nuclear modification of the gluon distribution
at small-x (gluon shadowing) using high-p_T prompt photon production at RHIC
and at LHC is discussed. The per-nucleon ratio, sigma(p+A -> gamma+X) / A
sigma(p+p -> gamma+X), is computed for both inclusive and isolated prompt
photons in perturbative QCD at NLO using different parametrizations of nuclear
parton densities, in order to assess the visibility of the shadowing signal.
The production of isolated photons turns out to be a promising channel which
allows for a reliable extraction of the gluon density, G^A/G^p, and the
structure function, F_2^A/F_2^p, in a nucleus over that in a proton. Moreover,
the production ratio of prompt photons at forward-over-backward rapidity in p-A
collisions provides an estimate of G^A/G^p (at small x) over F_2^A/F_2^p (at
large x), without the need of p-p reference data at the same energy.


title: Quantum critical scaling in graphene

abstract:
  We show that the emergent relativistic symmetry of electrons in graphene near
its quantum critical point (QCP) implies a crucial importance of the Coulomb
interaction. We derive scaling laws, valid near the QCP, that dictate the
nontrivial magnetic and charge response of interacting graphene. Our analysis
yields numerous predictions for how the Coulomb interaction will be manifested
in experimental observables such as the diamagnetic response and electronic
compressibility.


title: Fast Single-Charge Sensing with an rf Quantum Point Contact

abstract:
  We report high-bandwidth charge sensing measurements using a GaAs quantum
point contact embedded in a radio frequency impedance matching circuit
(rf-QPC). With the rf-QPC biased near pinch-off where it is most sensitive to
charge, we demonstrate a conductance sensitivity of 5x10^(-6) e^(2)/h Hz^(-1/2)
with a bandwidth of 8 MHz. Single-shot readout of a proximal few-electron
double quantum dot is investigated in a mode where the rf-QPC back-action is
rapidly switched.


title:
Discrete surface growth process as a synchronization mechanism for scale
  free complex networks

abstract:
  We consider the discrete surface growth process with relaxation to the
minimum [F. Family, J. Phys. A {\bf 19} L441, (1986).] as a possible
synchronization mechanism on scale-free networks, characterized by a degree
distribution $P(k) \sim k^{-\lambda}$, where $k$ is the degree of a node and
$\lambda$ his broadness, and compare it with the usually applied
Edward-Wilkinson process [S. F. Edwards and D. R. Wilkinson, Proc. R. Soc.
London Ser. A {\bf 381},17 (1982) ]. In spite of both processes belong to the
same universality class for Euclidean lattices, in this work we demonstrate
that for scale-free networks with exponents $\lambda<3$ this is not true.
Moreover, we show that for these ubiquitous cases the Edward-Wilkinson process
enhances spontaneously the synchronization when the system size is increased,
which is a non-physical result. Contrarily, the discrete surface growth process
do not present this flaw and is applicable for every $\lambda$.


title:
Electron-electron interaction and charging effects in graphene quantum
  dots

abstract:
  We analyze charging effects in graphene quantum dots. Using a simple model,
we show that, when the Fermi level is far from the neutrality point, charging
effects lead to a shift in the electrostatic potential and the dot shows
standard Coulomb blockade features. Near the neutrality point, surface states
are partially occupied and the Coulomb interaction leads to a strongly
correlated ground state which can be approximated by either a Wigner crystal or
a Laughlin like wave function. The existence of strong correlations modify the
transport properties which show non equilibrium effects, similar to those
predicted for tunneling into other strongly correlated systems.


title: Decomposability problem on branched coverings

abstract:
  Given a branched covering of degree d between closed surfaces, it determines
a collection of partitions of d, the branch data. In this work we show that any
branch data are realized by an indecomposable primitive branched covering on a
connected close surface N with Euler's characteristic less than or equal to 0.
This shows that decomposable and indecomposable realizations may coexist.
Moreover, we characterize the branch data of a decomposable primitive branched
covering.


title:
Relativistic Iron K Emission and absorption in the Seyfert 1.9 galaxy
  MCG-5-23-16

abstract:
  We present the results of the simultaneous deep XMM and Chandra observations
of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of
the best known examples of a relativistically broadened iron K-alpha line. The
time averaged spectral analysis shows that the iron K-shell complex is best
modeled with an unresolved narrow emission component (FWHM < 5000 km/s, EW ~ 60
eV) plus a broad component. This latter component has FWHM ~ 44000 km/s and EW
~ 50 eV. Its profile is well described by an emission line originating from an
accretion disk viewed with an inclination angle ~ 40^\circ and with the
emission arising from within a few tens of gravitational radii of the central
black hole. The time-resolved spectral analysis of the XMM EPIC-pn spectrum
shows that both the narrow and broad components of the Fe K emission line
appear to be constant in time within the errors. We detected a narrow sporadic
absorption line at 7.7 keV which appears to be variable on a time-scale of 20
ksec. If associated with Fe XXVI Ly-alpha this absorption is indicative of a
possibly variable, high ionization, high velocity outflow. The variability of
this absorption feature appears to rule out a local (z=0) origin. The analysis
of the XMM RGS spectrum reveals that the soft X-ray emission of MCG-5-23-16 is
likely dominated by several emission lines superimposed on an unabsorbed
scattered power-law continuum. The lack of strong Fe L shell emission together
with the detection of a strong forbidden line in the O VII triplet is
consistent with a scenario where the soft X-ray emission lines are produced in
a plasma photoionized by the nuclear emission.


title: Spectacular Shells in the Host Galaxy of the QSO MC2 1635+119

abstract:
  We present deep HST/ACS images and Keck spectroscopy of MC2 1635+119, a QSO
hosted by a galaxy previously classified as an undisturbed elliptical. Our new
images reveal dramatic shell structure indicative of a merger event in the
relatively recent past. The brightest shells in the central regions of the host
are distributed alternately in radius, with at least two distinct shells on one
side of the nucleus and three on the other, out to a distance of ~13 kpc. The
light within the five shells comprises ~6% of the total galaxy light. Lower
surface brightness ripples or tails and other debris extend out to a distance
of ~65 kpc. A simple N-body model for a merger reproduces the inner shell
structure and gives an estimate for the age of the merger between ~30 Myr and
~1.7 Gyr, depending on a range of reasonable assumptions. While the inner shell
structure is suggestive of a minor merger, the total light contribution from
the shells and extended structures are more indicative of a major merger. The
spectrum of the host galaxy is dominated by a population of intermediate age
(~1.4 Gyr), indicating a strong starburst episode that may have occurred at the
time of the merger event. We speculate that the current QSO activity may have
been triggered in the recent past by either a minor merger, or by debris from
an older (~Gyr) major merger that is currently ``raining'' back into the
central regions of the merger remnant.


title: Advanced topology on the multiscale sequence spaces S^\nu

abstract:
  We pursue the study of the multiscale spaces $S^\nu$ introduced by Jaffard in
the context of multifractal analysis. We give the necessary and sufficient
condition for $S^\nu$ to be locally p-convex, and exhibit a sequence of
$p$-norms that defines its natural topology. The strong topological dual of
$S^\nu$ is identified to another sequence space depending on $\nu$, endowed
with an inductive limit topology. As a particular case, we describe the dual of
a countable intersection of Besov spaces.


title:
Multiwavelength Monitoring of the Unusual Ultraluminous Supernova SN
  1978K in NGC 1313 and the Search for an Associated Gamma-Ray Burst

abstract:
  We discuss our radio (Australia Telescope Compact Array and Australian Long
Baseline Array) and X-ray (XMM-Newton) monitoring observations of the unusual
ultraluminous supernova SN 1978K in NGC 1313 at ~25 years after the explosion.
SN 1978K is a rare example of a Type IIn supernova that has remained bright
enough to have long-term X-ray and radio observations. The observations probe
the dense medium that was ejected by the progenitor star prior to its
explosion; the star might have been a Luminous Blue Variable. The radio imaging
shows that the source remains compact, but it may be marginally resolved. The
radio monitoring shows deviations from a smooth decay suggesting that
inhomogeneities are present in the radio emitting region. It appears that a
major change occurred in the mass-loss rate of the progenitor star shortly
before the supernova event. The X-ray emission between 2000 and 2006 is
consistent with the radiation coming from two shocks. All the X-ray data can be
fit using the same model (with no systematic evolution or short-term
variability) but this has a surprising requirement: the X-ray emitting regions
have a very large abundance of helium. This would be consistent with the X-ray
emitting shocks being located in a helium-rich layer that was ejected by the
progenitor star, or helium-rich material was ejected in the supernova
explosion. The unusual properties of the supernova motivated a search for an
associated gamma-ray burst (GRB). We show that SN 1978K was inside the ~4 sigma
error box of GRB 771029. If this association is correct, the GRB was
exceptionally underluminous. However, the quality of the gamma-ray burst
locations at that time was poor, and this is likely just a chance alignment.


title: On Randomness in Quantum Mechanics

abstract:
  The quantum mechanical probability densities are compared with the
probability densities treated by the theory of random variables. The relevance
of their difference for the interpretation of quantum mechanics is commented.


title:
$\mu-e$ conversion in nuclei within the CMSSM seesaw: universality
  versus non-universality

abstract:
  In this paper we study $\mu-e$ conversion in nuclei within the context of the
Constrained Minimal Supersymmetric Standard Model, enlarged by three right
handed neutrinos and their supersymmetric partners, and where the neutrino
masses are generated via a seesaw mechanism. Two different scenarios with
either universal or non-universal soft supersymmetry breaking Higgs masses at
the gauge coupling unification scale are considered. In the first part we
present a complete one-loop computation of the conversion rate for this process
that includes the photon-, $Z$-boson, and Higgs-boson penguins, as well as box
diagrams, and compare their size in the two considered scenarios. Then, in
these two scenarios we analyse the relevance of the various parameters on the
conversion rates, particularly emphasising the role played by the heavy
neutrino masses, $\tan \beta$, and especially $\theta_{13}$. In the case of
hierachical heavy neutrinos, an extremely high sensitivity of the rates to
$\theta_{13}$ is indeed found. The last part of this work is devoted to the
study of the interesting loss of correlation between the $\mu-e$ conversion and
$\mu \to e \gamma$ rates that occurs in the non-universal scenario. In the case
of large $\tan \beta$ and light $H^0$ Higgs boson an enhanced ratio of the
$\mu-e$ to $\mu \to e \gamma$ rates, with respect to the universal case is
found, and this could be tested with the future experimental sensitivities.


title:
Universal Control of Nuclear Spins Via Anisotropic Hyperfine
  Interactions

abstract:
  We show that nuclear spin subsystems can be completely controlled via
microwave irradiation of resolved anisotropic hyperfine interactions with a
nearby electron spin. Such indirect addressing of the nuclear spins via
coupling to an electron allows us to create nuclear spin gates whose
operational time is significantly faster than conventional direct addressing
methods. We experimentally demonstrate the feasibility of this method on a
solid-state ensemble system consisting of one electron and one nuclear spin.


title: Vacuum Fluctuations Cannot Mimic a Cosmological Constant

abstract:
  When the vacuum fluctuation pressure is calculated directly from fundamental
principles of quantum field theory, in the same manner as vacuum fluctuation
energy density is commonly calculated, one finds it is not equal to the
negative of the vacuum fluctuation energy density. Thus, vacuum fluctuations
cannot manifest as a cosmological constant of any order.


title: Dynamical breaking of U(1)_{R} and supersymmetry in a metastable vacuum

abstract:
  We consider the metastable N=1 QCD model of Intriligator, Seiberg and Shih
(ISS), deformed by adding a baryon term to the superpotential. This simple
deformation causes the spontaneous breaking of the approximate R-symmetry of
the metastable vacuum. We then gauge the flavour SU(5)_f and identify it with
the parent gauge symmetry of the Standard Model (SM). This implements direct
mediation of supersymmetry breaking without the need for an additional
messenger sector. A reasonable choice of parameters leads to gaugino masses of
the right order. Finally, we speculate that the entire ``ISS x SM'' model
should be interpreted as a magnetic dual of an (unknown) asymptotically free
theory.


title: Supersymmetric Unparticle Effects on Higgs Boson Mass and Dark Matter

abstract:
  We propose a model that introduces a supersymmetric unparticle operator in
the minimal supersymmetric Standard Model. We analyze the lowest dimension
operator involving an unparticle. This operator behaves as a Standard Model
gauge singlet and it introduces a new parameter into the Higgs potential which
can provide an alternative way to relax the upper limit on the lightest Higgs
boson mass. This operator also introduces several unparticle interactions which
can induce a neutral Higgsino to decay into a spinor unparticle. It also
induces violation of scale invariance around the electroweak scale. It is
necessary for the scale of this violation to be larger than the lightest
supersymmetric particle mass to maintain the latter as the usual weakly
interacting massive particle dark matter candidate. An alternative is to have
unparticle state as dark matter candidate. We also comment on some collider
implications.


title: Dynamical Friction and Galaxy Merging Timescales

abstract:
  The timescale for galaxies within merging dark matter halos to merge with
each other is an important ingredient in galaxy formation models. Accurate
estimates of merging timescales are required for predictions of astrophysical
quantities such as black hole binary merger rates, the build-up of stellar mass
in central galaxies, and the statistical properties of satellite galaxies
within dark matter halos. In this paper, we study the merging timescales of
extended dark matter halos using N-body simulations. We compare these results
to standard estimates based on the Chandrasekhar theory of dynamical friction.
We find that these standard predictions for merging timescales, which are often
used in semi-analytic galaxy formation models, are systematically shorter than
those found in simulations. The discrepancy is approximately a factor of 1.7
for $M_sat/M_host \approx 0.1$ and becomes larger for more disparate
satellite-to-host mass ratios, reaching a factor of $\sim 3.3$ for
$M_sat/M_host\approx 0.01$. Based on our simulations, we propose a new, easily
implementable fitting formula that accurately predicts the timescale for an
extended satellite to sink from the virial radius of a host halo down to the
halo's center for a wide range of $M_sat/M_host$ and orbits. Including a
central bulge in each galaxy changes the merging timescale by $\la 10%$. To
highlight one concrete application of our results, we show that merging
timescales often used in the literature overestimate the growth of stellar mass
by satellite accretion by $\approx 40 %$, with the extra mass gained in low
mass ratio mergers.


title: Scaling in the Fan of an Unconventional Quantum Critical Point

abstract:
  We present results of extensive finite-temperature Quantum Monte Carlo
simulations on a SU(2) symmetric S=1/2 quantum antiferromagnet with a four-spin
interaction [Sandvik, Phys. Rev. Lett. 98, 227202 (2007)]. Our simulations,
which are free of the sign-problem and carried out on lattices containing in
excess of 1.6 X 10^4 spins, indicate that the four-spin interaction destroys
the N\'eel order at an unconventional z=1 quantum critical point, producing a
valence-bond solid paramagnet. Our results are consistent with the `deconfined
quantum criticality' scenario.


title:
Decomposing Dusty Galaxies. I. Multi-Component Spectral Energy
  Distribution Fitting

abstract:
  We present a new multi-component spectral energy distribution (SED)
decomposition method and use it to analyze the ultraviolet to millimeter
wavelength SEDs of a sample of dusty infrared-luminous galaxies. SEDs are
constructed from spectroscopic and photometric data obtained with the Spitzer
Space Telescope, in conjunction with photometry from the literature. Each SED
is decomposed into emission from populations of stars, an AGN accretion disk,
PAHs, atomic and molecular lines, and distributions of graphite and silicate
grains. Decompositions of the SEDs of the template starburst galaxies NGC7714
and NGC2623 and the template AGNs PG0804+761 and Mrk463 provide baseline
properties to aid in quantifying the strength of star-formation and accretion
in the composite systems NGC6240 and Mrk1014. We find that obscured radiation
from stars is capable of powering the total dust emission from NGC6240,
although we cannot rule out a contribution from a deeply embedded AGN visible
only in X-rays. The decomposition of Mrk1014 is consistent with ~65% of its
power emerging from an AGN and ~35% from star-formation. We suggest that many
of the variations in our template starburst SEDs may be explained in terms of
the different mean optical depths through the clouds of dust surrounding the
young stars within each galaxy. Prompted by the divergent far-IR properties of
our template AGNs, we suggest that variations in the relative orientation of
their AGN accretion disks with respect to the disks of the galaxies hosting
them may result in different amounts of AGN-heated cold dust emission emerging
from their host galaxies. We estimate that 30-50% of the far-IR and PAH
emission from Mrk1014 may originate from such AGN-heated material in its host
galaxy disk.


title: Two-body transients in coupled atomic-molecular BECs

abstract:
  We discuss the dynamics of an atomic Bose-Einstein condensate when pairs of
atoms are converted into molecules by single-color photoassociation. Three main
regimes are found and it is shown that they can be understood on the basis of
time-dependent two-body theory. In particular, the so-called rogue dissociation
regime [Phys. Rev. Lett., 88, 090403 (2002)], which has a density-dependent
limit on the photoassociation rate, is identified with a transient regime of
the two-atom dynamics exhibiting universal properties. Finally, we illustrate
how these regimes could be explored by photoassociating condensates of
alkaline-earth atoms.


title: Magnetism in graphene nano-islands

abstract:
  We study the magnetic properties of nanometer-sized graphene structures with
triangular and hexagonal shapes terminated by zig-zag edges. We discuss how the
shape of the island, the imbalance in the number of atoms belonging to the two
graphene sublattices, the existence of zero-energy states, and the total and
local magnetic moment are intimately related. We consider electronic
interactions both in a mean-field approximation of the one-orbital Hubbard
model and with density functional calculations. Both descriptions yield values
for the ground state total spin, $S$, consistent with Lieb's theorem for
bipartite lattices. Triangles have a finite $S$ for all sizes whereas hexagons
have S=0 and develop local moments above a critical size of $\approx 1.5$ nm.


title:
A comprehensive study of Cepheid variables in the Andromeda galaxy.
  Period distribution, blending and distance determination

abstract:
  Extragalactic Cepheids are the basic rungs of the cosmic distance scale. They
are excellent standard candles, although their luminosities and corresponding
distance estimates can be affected by the particular properties of the host
galaxy. Therefore, the accurate analysis of the Cepheid population in other
galaxies, and notably in the Andromeda Galaxy (M31), is crucial to obtaining
reliable distance determinations. We obtained accurate photometry (in B and V
passbands) of 416 Cepheids in M31 over a five year campaign within a survey
aimed at the detection of eclipsing binaries. The resulting Cepheid sample is
the most complete in M31 and has almost the same period distribution as the
David Dunlap Observatory sample in the Milky Way. The large number of epochs
(~250 per filter) has permitted the characterisation of the pulsation modes of
356 Cepheids, with 281 of them pulsating in the fundamental mode and 75 in the
first overtone. The period-luminosity relationship of the fundamental mode
Cepheids has been studied and a new approach has been used to estimate the
effect of blending. We find that the blending contribution is as important as
the metallicity correction when computing Cepheid distance determinations to
M31 (~0.1 mag). Since large amplitude Cepheids are less affected by blending,
we have used those with an amplitude A_V>0.8 mag to derive a distance to M31 of
(m-M)_0=24.32+/-0.12 mag.


title: Graphene based spin field effect transistor

abstract:
  A spin field effect transistor (FET) is proposed by utilizing a graphene
nanoribbon as the channel. Similar to the conventional spin FETs, the device
involves ferromagnetic metals as a source and drain; they, in turn, are
connected to the graphene channel. Due to the negligible spin-orbital coupling
in the carbon based materials, the bias can accomplishes spin manipulation by
means of electrical control of electron exchange interaction with a
ferromagnetic dielectric attached to the nanoribbon between source and drain.
The numerical estimations show the feasibility of graphene-based spin FET if a
bias varies exchange interaction on the amount around 5 meV. It was shown that
the device stability to the thermal dispersion can provide the armchair
nanoribbons of specific width that keeps the Dirac point in electron dispersion
law.


title: Analytic Resolution of Puzzle in $B\to K \pi$ decays

abstract:
  We present a systematic method to extract each standard model (SM)-{\it like}
hadronic parameter as well as new physics parameters in analytic way for $B\to
K\pi$ decays. Using the analytic method to the currently available experimental
data, we find two possible solutions analytically equivalent: one showing the
large SM-{\it like} color-suppressed tree contribution and the other showing
the large SM-{\it like} EWP contribution. The magnitude of the NP amplitude and
its weak phase are quite large. For instance, we find $|P^{NP}/P| =
0.39\pm0.13$, $\phi^{NP}=91^\circ\pm15^\circ$ and
$\delta^{NP}=8^\circ\pm27^\circ$, which are the ratio of the NP-to-SM
contribution, the weak and the relative strong phase of the NP amplitude,
respectively.


title:
Structure and evolution of Zel'dovich pancakes as probes of dark energy
  models

abstract:
  We examine how coupled dark matter and dark energy modify the development of
Zel'dovich pancakes. We study how the various effects of these theories, such
as a fifth force in the dark sector and a modified particle Hubble drag,
produce variations in the redshifts of caustic formation and the present-day
density profiles of pancakes. We compare our results in direct simulation to a
perturbation theory approach for the dark energy scalar field. We determine the
range of initial scalar field amplitudes for which perturbation theory is
accurate in describing the development of the pancakes. Notably, we find that
perturbative methods which neglect kinetic terms in the scalar field equation
of motion are not valid for arbitrarily small perturbations. We also examine
whether models that have been tuned to match the constraints of current
observations can produce new observable effects in the nonlinear structure of
pancakes. Our results suggest that a fully realistic three-dimensional
simulation will produce significant new observable features, such as
modifications to the mass function and halo radial density profile shapes, that
can be used to distinguish these models from standard concordance cosmology and
from each other.


title: About the Characteristic Function of a Set

abstract:
  In this paper we give a method, based on the characteristic function of a
set, to solve some difficult problems of set theory in undergraduate research.


title: Implications of Interstellar Dust and Magnetic Field at the Heliosphere

abstract:
  Tiny interstellar dust grains causing the polarization of light from the
nearest stars are deflected sideways in the outer heliosheath regions, along
with the interstellar magnetic field. Observations of optical polarization of
stars beyond the heliosphere nose, suggest the direction of the upwind
interstellar magnetic field is relatively constant. The polarizations of nearby
stars and offset angle between HeI and HeI flowing into the heliosphere have
position angles in galactic coordinates of 30- 40 deg, indicating a local
magnetic field direction inclined by ~55 deg and ~65 deg, respectively, with
respect to the galactic and ecliptic planes. The hot and cold poles of the
measured Cosmic Microwave Background (CMB) dipole moment are nearly symmetric
around the heliosphere nose direction, and the v^{22} quadrupole vector is
directed towards the heliosphere nose. The area vectors of the CMB quadrupole
and ocotopole moments are directed towards the band perpendicular to the
ecliptic plane formed by the alternate locations for the 3 kHz emissions
detected by Voyagers 1 and 2. In the upwind direction, the position angle of
the null plane separating the CMB dipole hot and cold poles is nearly aligned
with the interstellar magnetic field direction at the Sun. Heliospheric
foreground contamination of the low-$\ell$ CMB modes now requires detailed
study.


title: Microlensing by Cosmic Strings

abstract:
  We consider the signature and detectability of gravitational microlensing of
distant quasars by cosmic strings. Because of the simple image configuration
such events will have a characteristic light curve, in which a source would
appear to brighten by exactly a factor of two, before reverting to its original
apparent brightness. We calculate the optical depth and event rate, and
conclude that current predictions and limits on the total length of strings on
the sky imply optical depths of $\la 10^{-8}$ and event rates of fewer than one
event per $10^9$ sources per year. Disregarding those predictions but replacing
them with limits on the density of cosmic strings from the CMB fluctuation
spectrum, leaves only a small region of parameter space (in which the sky
contains about $3\times10^5$ strings with deficit angle of order 0.3
milli-arcseconds) for which a microlensing survey of exposure $10^7$
source-years, spanning a 20--40-year period, might reveal the presence of
cosmic strings.


title: The Integral (orbifold) Chow Ring of Toric Deligne-Mumford Stacks

abstract:
  In this paper we study the integral Chow ring of toric Deligne-Mumford
stacks. We prove that the integral Chow ring of a semi-projective toric
Deligne-Mumford stack is isomorphic to the Stanley-Reisner ring of the
associated stacky fan. The integral orbifold Chow ring is also computed. Our
results are illustrated with several examples.


title: Color Transfer in Associated Heavy-Quarkonium Production

abstract:
  We study the production of heavy quarkonium in association with an additional
heavy pair. We argue that important contributions may come from phase space
regions where three heavy fermions are separated by relative velocities much
lower than the speed of light, and to which standard effective field theories
do not apply. In this region, infrared sensitive color exchange is specific to
the presence of the unpaired (anti)quark. This effect vanishes as the motion of
the additional particle becomes relativistic with respect to the pair, and is
completely absent for massless quarks and gluons in the final state.


title: Compactness results for the K\"ahler-Ricci flow

abstract:
  We consider the K\"ahler-Ricci flow $\frac{\partial}{\partial t}g_{i\bar{j}}
= g_{i\bar{j}} - R_{i\bar{j}}$ on a compact K\"ahler manifold $M$ with $c_1(M)
> 0$, of complex dimension $k$.
  We prove the $\epsilon$-regularity lemma for the K\"ahler-Ricci flow, based
on Moser's iteration. Assume that the Ricci curvature and $\int_M |\rem|^k
dV_t$ are uniformly bounded along the flow. Using the $\epsilon$-regularity
lemma we derive the compactness result for the K\"ahler-Ricci flow. Under our
assumptions, if $k \ge 3$ in addition, using the compactness result we show
that $|\rem| \le C$ holds uniformly along the flow. This means the flow does
not develop any singularities at infinity. We use some ideas of Tian from
\cite{Ti} to prove the smoothing property in that case.


title: Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations

abstract:
  We describe the diffusion and random velocities of solid particles due to
stochastic forcing by turbulent gas. We include the orbital dynamics of
Keplerian disks, both in-plane epicycles and vertical oscillations. We obtain a
new result for the diffusion of solids. The Schmidt number (ratio of gas to
particle diffusivity) is Sc = 1 + (Omega t_stop)^2, in terms of the particle
stopping time, t_stop, and the orbital frequency, Omega. The standard result,
Sc = 1 + t_stop/t_eddy, in terms of the eddy turnover time, t_eddy, is shown to
be incorrect. The main difference is that Sc rises quadratically, not linearly,
with stopping time. Consequently, particles larger than ~ 10 cm in
protoplanetary disks will suffer less radial diffusion and will settle closer
to the midplane. Such a layer of boulders would be more prone to gravitational
collapse. Our predictions of RMS speeds, vertical scale height and diffusion
coefficients will help interpret numerical simulations. We confirm previous
results for the vertical stirring of particles (scale heights and random
velocities), and add a correction for arbitrary ratios of eddy to orbital
times. The particle layer becomes thinner for t_eddy > 1/Omega, with the
strength of turbulent diffusion held fixed. We use two analytic techniques --
the Hinze-Tchen formalism and the Fokker-Planck equation with velocity
diffusion -- with identical results when the regimes of validity overlap. We
include simple physical arguments for the scaling of our results.


title:
Tate-Shafarevich Groups and Frobenius Fields of Reductions of Elliptic
  Curves

abstract:
  Let $\E/\Q$ be a fixed elliptic curve over $\Q$ which does not have complex
multiplication. Assuming the Generalized Riemann Hypothesis, A. C. Cojocaru and
W. Duke have obtained an asymptotic formula for the number of primes $p\le x$
such that the reduction of $\E$ modulo p has a trivial Tate-Shafarevich group.
Recent results of A. C. Cojocaru and C. David lead to a better error term. We
introduce a new argument in the scheme of the proof which gives further
improvement.


title: N=4 Supersymmetric Yang-Mills Multiplet in Non-Adjoint Representations

abstract:
  We formulate a theory for N=4 supersymmetric Yang-Mills multiplet in a
non-adjoint representation R of SO(N) as an important application of our
recently-proposed model for N=1 supersymmetry. This system is obtained by
dimensional reduction from an N=1 supersymmetric Yang-Mills multiplet in
non-adjoint representation in ten dimensions. The consistency with
supersymmetry requires that the non-adjoint representation R with the indices
i, j, ... satisfy the three conditions \eta^{i j} = \delta^{i j}, (T^I)^{i j} =
- (T^I)^{j i} and (T^I)^{[ i j |} (T^I)^{| k ] l} = 0 for the metric \eta^{i j}
and the generators T^I, which are the same as the N=1 case.


title:
Raman Scattered O VI $\lambda$ 6825 and the Accretion Disk Emission
  Model in the Symbiotic Stars V1016 Cygni and HM Sagittae

abstract:
  We present the high resolution spectra of the D type symbiotic stars V1016
Cygni and HM Sagittae obtained with the Bohyunsan Optical Echelle Spectrograph
(BOES), and investigate the double-peaked asymmetric profiles of the Raman
scattered O VI 6825. By adopting a wind accretion disk model, we assume that
the O VI emission region is described by a Keplerian thin disk. The Raman
scattering occurs in a neutral region near the giant, taking in the form of a
slow stellar wind, part of which is ionized by the strong UV radiation from the
hot white dwarf. Using a Monte Carlo technique, we compute the line profiles
that are modulated by the slow spherical stellar wind from the giant component
with the ionization front approximated by a hyperboloid. In order to account
for the asymmetry and the existence of a central dip in the profiles, we add an
O VI resonance scattering region between the hot white dwarf and the giant star
which hinders the incidence of slightly blue O VI photons upon the H I region.
Overall good fits to the observed data are obtained from our model, which lends
support to the accretion disk emission model in these objects. The best fitting
parameters for V1016 Cyg are $v_o=30{\rm km s^{-1}}$,
  $v_\infty=11{\rm km s^{-1}}$, and $v_{c}=10{\rm km s^{-1}}$, where $v_o$,
$v_\infty$ and $v_{c}$ are the velocity of the outer disk rim, the terminal
velocity of the giant wind, and the velocity component of the resonance
scattering O VI region along the binary axis, respectively. Similar fitting
parameters $v_o=27{\rm km s^{-1}}$, $v_\infty=10{\rm km s^{-1}}$ and
$v_{c}=9{\rm km s^{-1}}$ are obtained for HM Sge. We also investigate the
effect of a hot spot in a disk that is well known in accretion disks in
cataclysmic variables.


title:
High Spatial Resolution Observations of Two Young Protostars in the R
  Corona Australis Region

abstract:
  We present multi-wavelength, high spatial resolution imaging of the IRS 7
region in the R Corona Australis molecular cloud. Our observations include 1.1
mm continuum and HCO^+ J = $3 \to 2$ images from the SMA, ^{12}CO J = $3 \to 2$
outflow maps from the DesertStar heterodyne array receiver on the HHT, 450
$\mu$m and 850 $\mu$m continuum images from SCUBA, and archival Spitzer IRAC
and MIPS 24 \micron images. The accurate astrometry of the IRAC images allow us
to identify IRS 7 with the cm source VLA 10W (IRS 7A) and the X-ray source X_W.
The SMA 1.1 mm image reveals two compact continuum sources which are also
distinguishable at 450 $\mu$m. SMA 1 coincides with X-ray source CXOU
J190156.4-365728 and VLA cm source 10E (IRS 7B) and is seen in the IRAC and
MIPS images. SMA 2 has no infrared counterpart but coincides with cm source VLA
9. Spectral energy distributions constructed from SMA, SCUBA and Spitzer data
yield bolometric temperatures of 83 K for SMA 1 and $\leq$70 K for SMA 2. These
temperatures along with the submillimeter to total luminosity ratios indicate
that SMA 2 is a Class 0 protostar, while SMA 1 is a Class 0/Class I
transitional object (L=$17\pm6$ \Lsun). The ^{12}CO J = $3 \to 2$ outflow map
shows one major and possibly several smaller outflows centered on the IRS 7
region, with masses and energetics consistent with previous work. We identify
the Class 0 source SMA 2/VLA 9 as the main driver of this outflow. The complex
and clumpy spatial and velocity distribution of the HCO^+ J = $3 \to 2$
emission is not consistent with either bulk rotation, or any known molecular
outflow activity.


title:
Measurement of the CP-Violating Asymmetries in B0 -> KS pi0 and of the
  Branching Fraction of B0 -> K0 pi0

abstract:
  We present a measurement of the time-dependent CP-violating asymmetries in
$B^0 \to K^0_{\scriptscriptstyle S}\pi^0$ decays based on 383 million
$\Upsilon(4S)\to B\kern 0.18em\bar{\kern -0.18em B}$ events collected by the
\mbox{\slshape B\kern-0.1em{\smaller A}\kern-0.1em B\kern-0.1em{\smaller
A\kern-0.2em R}} experiment at the PEP-II asymmetric-energy $B$ Factory at
SLAC. We measure the direct CP-violating asymmetry $C_{K^0_{\scriptscriptstyle
S}\pi^0} = 0.24 \pm 0.15 \pm 0.03$ and the CP-violating asymmetry in the
interference between mixing and decay $S_{K^0_{\scriptscriptstyle S}\pi^0} =
0.40 \pm 0.23 \pm 0.03$, where the first errors are statistical and the second
are systematic. On the same sample, we measure the decay branching fraction,
obtaining ${\cal B}(B^0 \to K^0\pi^0)= (10.3 \pm 0.7 \pm 0.6)\times 10^{-6}$.


title:
Exclusive branching fraction measurements of semileptonic tau decays
  into three charged hadrons, $\tau^- \to \phi \pi^- \nu_\tau$ and $\tau^- \to
  \phi K^- \nu_\tau$

abstract:
  Using a data sample corresponding to an integrated luminosity of 342
$fb^{-1}$ collected with the BABAR detector at the SLAC PEP-II
electron-positron storage ring operating at a center-of-mass energy near 10.58
GeV, we measure ${\cal{B}} (\tau^- \to \pi^- \pi^- \pi^+ \nu_\tau) = (8.83 \pm
0.01 \pm 0.13) %$, ${\cal{B}} (\tau^- \to K^- \pi^- \pi^+ \nu_\tau) = (0.273\pm
0.002\pm 0.009)%$, ${\cal{B}} (\tau^- \to K^- \pi^- K^+ \nu_\tau) = (0.1346\pm
0.0010 \pm 0.0036)%$ and ${\cal{B}} (\tau^- \to K^- K^- K^+ \nu_\tau) =
(1.58\pm 0.13 \pm 0.12)\times 10^{-5}$, where the uncertainties are statistical
and systematic, respectively. Events where the $\pi^+\pi^-$ pair is consistent
with coming from a $K^0_S$ are excluded. These are significant improvements
over previous measurements, with the ${\cal{B}} (\tau^- \to K^- K^- K^+
\nu_\tau)$ result being the first resonant plus non-resonant measurement of
this mode. We also report a first measurement of ${\cal{B}} (\tau^- \to
\phi\pi^- \nu_\tau) = (3.42\pm 0.55 \pm 0.25)\times 10^{-5}$ and a new
measurement of ${\cal{B}} (\tau^- \to \phi K^- \nu_\tau) = (3.39\pm 0.20 \pm
0.28)\times 10^{-5}$.


title:
LISA detections of massive black hole inspirals: parameter extraction
  errors due to inaccurate template waveforms

abstract:
  The planned Laser Interferometer Space Antenna (LISA) is expected to detect
the inspiral and merger of massive black hole binaries (MBHBs) at z <~ 5 with
signal-to-noise ratios (SNRs) of hundreds to thousands. Because of these high
SNRs, and because these SNRs accrete over periods of weeks to months, it should
be possible to extract the physical parameters of these systems with high
accuracy; for instance, for a ~ 10^6 Msun MBHBs at z = 1 it should be possible
to determine the two masses to ~ 0.1% and the sky location to ~ 1 degree.
However, those are just the errors due to noise: there will be additional
"theoretical" errors due to inaccuracies in our best model waveforms, which are
still only approximate. The goal of this paper is to estimate the typical
magnitude of these theoretical errors. We develop mathematical tools for this
purpose, and apply them to a somewhat simplified version of the MBHB problem,
in which we consider just the inspiral part of the waveform and neglect
spin-induced precession, eccentricity, and PN amplitude corrections. For this
simplified version, we estimate that theoretical uncertainties in sky position
will typically be ~ 1 degree, i.e., comparable to the statistical uncertainty.
For the mass and spin parameters, our results suggest that while theoretical
errors will be rather small absolutely, they could still dominate over
statistical errors (by roughly an order of magnitude) for the strongest
sources. The tools developed here should be useful for estimating the magnitude
of theoretical errors in many other problems in gravitational-wave astronomy.


title: Excitonic Effects in the Optical Spectra of Graphene Nanoribbons

abstract:
  We present a first-principles calculation of the optical properties of
armchair-edged graphene nanoribbons (AGNRs) with many-electron effects
included. The reduced dimensionality of the AGNRs gives rise to an enhanced
electron-hole binding energy for both bright and dark exciton states (0.8-1.4
eV for GNRs with width w ~ 1.2 nm) and dramatically changes the optical spectra
owing to a near complete transfer of oscillator strength to the exciton states
from the continuum transitions. The characteristics of the excitons of the
three distinct families of AGNRs are compared and discussed. The enhanced
excitonic effects found here are expected to be of importance in optoelectronic
applications of graphene-based nanostructures.


title: Canonical lifts of the Johnson homomorphisms to the Torelli groupoid

abstract:
  We prove that every trivalent marked bordered fatgraph comes equipped with a
canonical generalized Magnus expansion in the sense of Kawazumi. This Magnus
expansion is used to give canonical lifts of the higher Johnson homomorphisms
$\tau_m$, for $m\geq 1$, to the Torelli groupoid, and we provide a recursive
combinatorial formula for tensor representatives of these lifts. In particular,
we give an explicit 1-cocycle in the dual fatgraph complex which lifts $\tau_2$
and thus answer affirmatively a question of Morita-Penner. To illustrate our
techniques for calculating higher Johnson homomorphisms in general, we give
explicit examples calculating $\tau_m$, for $m\leq 3$.


title: Second order arithmetic means in operator ideals

abstract:
  Equality of the second order arithmetic means of two principal ideals does
not imply equality of their first order arithmetic means (second order equality
cancellation). We provide fairly broad sufficient conditions on one of the
principal ideals for this implication to hold true. We present also sufficient
conditions for second order inclusion cancellations. These conditions are
formulated in terms of the growth properties of the ratio of regularity
sequence associated to the sequence of s-number of a generator of the principal
ideal. These results are then extended to general ideals.


title: Gromov-Witten invariants of varieties with holomorphic 2-forms

abstract:
  We show that a holomorphic two-form $\theta$ on a smooth algebraic variety X
localizes the virtual fundamental class of the moduli of stable maps
$\mgn(X,\beta)$ to the locus where $\theta$ degenerates; it then enables us to
define the localized GW-invariant, an algebro-geometric analogue of the local
invariant of Lee and Parker in symplectic geometry, which coincides with the
ordinary GW-invariant when X is proper. It is deformation invariant. Using
this, we prove formulas for low degree GW-invariants of minimal general type
surfaces with p_g>0 conjectured by Maulik and Pandharipande.


title:
On the Significance of the Weyl Curvature in a Relativistic Cosmological
  Model

abstract:
  The Weyl curvature includes the Newtonian field and an additional field, the
so-called anti-Newtonian. In this paper, we use the Bianchi and Ricci
identities to provide a set of constraints and propagations for the Weyl
fields. The temporal evolutions of propagations manifest explicit solutions of
gravitational waves. We see that models with purely Newtonian field are
inconsistent with relativistic models and obstruct sounding solutions.
Therefore, both fields are necessary for the nonlocal nature and radiative
solutions of gravitation.


title:
Non-equilibrium statistical mechanics of classical nuclei interacting
  with the quantum electron gas

abstract:
  Kinetic equations governing time evolution of positions and momenta of atoms
in extended systems are derived using quantum-classical ensembles within the
Non-Equilibrium Statistical Operator Method (NESOM). Ions are treated
classically, while their electrons quantum mechanically; however, the
statistical operator is not factorised in any way and no simplifying
assumptions are made concerning the electronic subsystem. Using this method, we
derive kinetic equations of motion for the classical degrees of freedom (atoms)
which account fully for the interaction and energy exchange with the quantum
variables (electrons). Our equations, alongside the usual Newtonian-like terms
normally associated with the Ehrenfest dynamics, contain additional terms,
proportional to the atoms velocities, which can be associated with the
electronic friction. Possible ways of calculating the friction forces which are
shown to be given via complicated non-equilibrium correlation functions, are
discussed. In particular, we demonstrate that the correlation functions are
directly related to the thermodynamic Matsubara Green's functions, and this
relationship allows for the diagrammatic methods to be used in treating
electron-electron interaction perturbatively when calculating the correlation
functions. This work also generalises previous attempts, mostly based on model
systems, of introducing the electronic friction into Molecular Dynamics
equations of atoms.


title: Conformal Ricci and Matter Collineations for Anisotropic Fluid

abstract:
  We study the consequences of timelike and spaccelike conformal Ricci and
conformal matter collineations for anisotropic fluid in the context of General
Relativity. Necessary and sufficient conditions are derived for a spacetime
with anisotropic fluid to admit conformal Ricci and conformal matter
collineations parallel to u^a and x^a. These conditions for timelike and
spacelike conformal Ricci and conformal matter collineations for anisotropic
fluid reduce to the conditions of perfect fluid when the heat flux and the
traceless anisotropic stress tensor vanish. Further, for $\alpha=0$ (the
conformal factor), we recover the earlier results of Ricci collineations and
matter collineations in each case of timelike and spacelike conformal Ricci
collineations and conformal matter collineations for the perfect fluid. Thus
our results give the generalization of the results already available in the
literature. It is worth noticing that the conditions of conformal matter
collineations can be derived from the conditions of conformal Ricci
collineations or vice versa under certain constraints.


title:
Suppression of High Transverse Momentum $\pi^0$ Spectra in Au+Au
  Collisions at RHIC

abstract:
  Au+Au, $s^{1/2} = 200$ A GeV measurements at RHIC, obtained with the PHENIX,
STAR, PHOBOS and BRAHMS detectors, have all indicated a suppression of neutral
pion production, relative to an appropriately normalized NN level. For central
collisions and vanishing pseudo-rapidity these experiments exhibit suppression
in charged meson production, especially at medium to large transverse momenta.
In the PHENIX experiment similar behavior has been reported for $\pi^0$
spectra.
  In a recent work on the simpler D+Au interaction, to be considered perhaps as
a tune-up for Au+Au, we reported on a pre-hadronic cascade mechanism which
explains the mixed observation of moderately reduced $p_\perp$ suppression at
higher pseudo-rapidity as well as the Cronin enhancement at mid-rapidity. Here
we present the extension of this work to the more massive ion-ion collisions.
  Our major thesis is that much of the suppression is generated in a late stage
cascade of colourless pre-hadrons produced after an initial short-lived
coloured phase. We present a pQCD argument to justify this approach and to
estimate the time duration $\tau_p$ of this initial phase. Of essential
importance is the brevity in time of the coloured phase existence relative to
that of the strongly interacting pre-hadron phase. The split into two phases is
of course not sharp in time, but adequate for treating the suppression of
moderate and high $p_\perp$ mesons.


title: Graphic-Card Cluster for Astrophysics (GraCCA) -- Performance Tests

abstract:
  In this paper, we describe the architecture and performance of the GraCCA
system, a Graphic-Card Cluster for Astrophysics simulations. It consists of 16
nodes, with each node equipped with 2 modern graphic cards, the NVIDIA GeForce
8800 GTX. This computing cluster provides a theoretical performance of 16.2
TFLOPS. To demonstrate its performance in astrophysics computation, we have
implemented a parallel direct N-body simulation program with shared time-step
algorithm in this system. Our system achieves a measured performance of 7.1
TFLOPS and a parallel efficiency of 90% for simulating a globular cluster of
1024K particles. In comparing with the GRAPE-6A cluster at RIT (Rochester
Institute of Technology), the GraCCA system achieves a more than twice higher
measured speed and an even higher performance-per-dollar ratio. Moreover, our
system can handle up to 320M particles and can serve as a general-purpose
computing cluster for a wide range of astrophysics problems.


title: Hartree-Fock calculations of a finite inhomogeneous quantum wire

abstract:
  We use the Hartree-Fock method to study an interacting one-dimensional
electron system on a finite wire, partially depleted at the center by a smooth
potential barrier. A uniform one-Tesla Zeeman field is applied throughout the
system. We find that with the increase in the potential barrier, the low
density electrons under it go from a non-magnetic state to an antiferromagnetic
state, and then to a state with a well-localized spin-aligned region isolated
by two antiferromagnetic regions from the high density leads. At this final
stage, in response to a continuously increasing barrier potential, the system
undergoes a series of abrupt density changes, corresponding to the successive
expulsion of a single electron from the spin-aligned region under the barrier.
Motivated by the recent momentum-resolved tunneling experiments in a parallel
wire geometry, we also compute the momentum resolved tunneling matrix elements.
Our calculations suggest that the eigenstates being expelled are spatially
localized, consistent with the experimental observations. However, additional
mechanisms are needed to account for the experimentally observed large spectral
weight at near $k=0$ in the tunneling matrix elements.


title:
Revised metallicity classes for low-mass stars: dwarfs (dM), subdwarfs
  (sdM), extreme subdwarfs (esdM), and ultra subdwarfs (usdM)

abstract:
  The current classification system of M stars on the main sequence
distinguishes three metallicity classes (dwarfs - dM, subdwarfs - sdM, and
extreme subdwarfs - esdM). The spectroscopic definition of these classes is
based on the relative strength of prominent CaH and TiO molecular absorption
bands near 7000A, as quantified by three spectroscopic indices (CaH2, CaH3, and
TiO5). We re-examine this classification system in light of our ongoing
spectroscopic survey of stars with proper motion \mu > 0.45 "/yr, which has
increased the census of spectroscopically identified metal-poor M stars to over
400 objects. Kinematic separation of disk dwarfs and halo subdwarfs suggest
deficiencies in the current classification system. Observations of common
proper motion doubles indicates that the current dM/sdM and sdM/esdM boundaries
in the [TiO5,CaH2+CaH3] index plane do not follow iso-metallicity contours,
leaving some binaries inappropriately classified as dM+sdM or sdM+esdM. We
propose a revision of the classification system based on an empirical
calibration of the TiO/CaH ratio for stars of near solar metallicity. We
introduce the parameter \zeta_{TiO/CaH} which quantifies the weakening of the
TiO bandstrength due to metallicity effect, with values ranging from
\zeta_{TiO/CaH}=1 for stars of near-solar metallicity to \zeta_{TiO/CaH}~0 for
the most metal-poor (and TiO depleted) subdwarfs. We redefine the metallicity
classes based on the value of the parameter \zeta_{TiO/CaH}; and refine the
scheme by introducing an additional class of ultra subdwarfs (usdM). We
introduce sequences of sdM, esdM, and usdM stars to be used as formal
classification standards.


title: Card shuffling and diophantine approximation

abstract:
  The ``overlapping-cycles shuffle'' mixes a deck of $n$ cards by moving either
the $n$th card or the $(n-k)$th card to the top of the deck, with probability
half each. We determine the spectral gap for the location of a single card,
which, as a function of $k$ and $n$, has surprising behavior. For example,
suppose $k$ is the closest integer to $\alpha n$ for a fixed real
$\alpha\in(0,1)$. Then for rational $\alpha$ the spectral gap is
$\Theta(n^{-2})$, while for poorly approximable irrational numbers $\alpha$,
such as the reciprocal of the golden ratio, the spectral gap is
$\Theta(n^{-3/2})$.


title: Triple Hilbert transforms along polynomial surfaces

abstract:
  This paper has been withdrawn since it contains some discrepancy with othe
authers's recent result. We will not post this until this discrepancy is
resolved.


title:
Continuous and discontinuous phase transitions and partial
  synchronization in stochastic three-state oscillators

abstract:
  We investigate both continuous (second-order) and discontinuous (first-order)
transitions to macroscopic synchronization within a single class of discrete,
stochastic (globally) phase-coupled oscillators. We provide analytical and
numerical evidence that the continuity of the transition depends on the
coupling coefficients and, in some nonuniform populations, on the degree of
quenched disorder. Hence, in a relatively simple setting this class of models
exhibits the qualitative behaviors characteristic of a variety of considerably
more complicated models. In addition, we study the microscopic basis of
synchronization above threshold and detail the counterintuitive subtleties
relating measurements of time averaged frequencies and mean field oscillations.
Most notably, we observe a state of suprathreshold partial synchronization in
which time-averaged frequency measurements from individual oscillators do not
correspond to the frequency of macroscopic oscillations observed in the
population.


title: Modelling chemical reactions using semiconductor quantum dots

abstract:
  We propose using semiconductor quantum dots for a simulation of chemical
reactions as electrons are redistributed among such artificial atoms. We show
that it is possible to achieve various reaction regimes and obtain different
reaction products by varying the speed of voltage changes applied to the gates
forming quantum dots. Considering the simplest possible reaction, $H_2+H\to
H+H_2$, we show how the necessary initial state can be obtained and what
voltage pulses should be applied to achieve a desirable final product. Our
calculations have been performed using the Pechukas gas approach, which can be
extended for more complicated reactions.


title: Building a Cooperative Communications System

abstract:
  In this paper, we present the results from over-the-air experiments of a
complete implementation of an amplify and forward cooperative communications
system. Our custom OFDM-based physical layer uses a distributed version of the
Alamouti block code, where the relay sends one branch of Alamouti encoded
symbols. First we show analytically and experimentally that amplify and forward
protocols are unaffected by carrier frequency offsets at the relay. This result
allows us to use a conventional Alamouti receiver without change for the
distributed relay system. Our full system implementation shows gains up to
5.5dB in peak power constrained networks. Thus, we can conclusively state that
even the simplest form of relaying can lead to significant gains in practical
implementations.


title: Soft Modes at the Stacking Faults in SiC Crystals

abstract:
  We use first-principles calculations based on density functional theory to
determine and understand the driving force of the observed stacking fault
expansion in SiC. We verify the suggestion based on recent experiments that the
free energy difference between the faulted and the perfect structures is
responsible for this expansion, and show that its origin lies in a large
entropy associated with soft vibrational modes of the faulted SiC structure.
These soft modes involve shearing of SiC on a long length-scale and are absent
in related group IV semiconductors, such as Si, Ge and C.


title: Analytical solutions for black-hole critical behaviour

abstract:
  Dynamical Einstein cluster is a spherical self-gravitating system of
counterrotating particles, which may expand, oscillate and collapse. This
system exhibits critical behaviour in its collapse at the threshold of black
hole formation. It appears when the specific angular momentum of particles is
tuned finely to the critical value. We find the unique exact self-similar
solution at the threshold. This solution begins with a regular surface,
involves timelike naked singularity formation and asymptotically approaches a
static self-similar cluster.


title: Optimality of feedback control strategies for qubit purification

abstract:
  Recently two papers [K. Jacobs, Phys. Rev. A {\bf 67}, 030301(R) (2003); H.
M. Wiseman and J. F. Ralph, New J. Physics {\bf 8}, 90 (2006)] have derived
control strategies for rapid purification of qubits, optimized with respect to
various goals. In the former paper the proof of optimality was not
mathematically rigorous, while the latter gave only heuristic arguments for
optimality. In this paper we provide rigorous proofs of optimality in all
cases, by applying simple concepts from optimal control theory, including
Bellman equations and verification theorems.


title: SIC-POVMs exist in all dimensions

abstract: This paper has been withdrawn by the author due to mathematical errors.


title: Energy Dependence of Scattering Ground State Polar Molecules

abstract:
  We explore the total cross section of ground state polar molecules in an
electric field at various energies, focusing on RbCs and RbK. An external
electric field polarizes the molecules and induces strong dipolar interactions
leading to non-zero partial waves contributing to the scattering even as the
collision energy goes to zero. This results in the need to compute scattering
problems with many different values of total M to converge the total cross
section. An accurate and efficient approximate total cross section is
introduced and used to study the low field temperature dependence. To
understand the scattering of the polar molecules we compare a semi-classical
cross section with quantum unitarity limit. This comparison leads to the
ability to characterize the scattering based on the value of the electric field
and the collision energy.


title:
Electronic transport in graphene: A semi-classical approach including
  midgap states

abstract:
  Using the semi-classical Boltzmann theory, we calculate the conductivity as
function of the carrier density. As usually, we include the scattering from
charged impurities, but conclude that the estimated impurity density is too low
in order to explain the experimentally observed mobilities. We thus propose an
additional scattering mechanism involving midgap states which leads to a
similar k-dependence of the relaxation time as charged impurities. The new
scattering mechanism can account for the experimental findings such as the
sublinear behavior of the conductivity versus gate voltage and the increase of
the minimal conductivity for clean samples. We also discuss temperature
dependent scattering due to acoustic phonons.


title:
Search for the Rare Decays $J/\psi \to D_{S}^{-} \pi^{+}$, $J/\psi \to
  D^{-} \pi^{+}$, and $J/\psi \to \bar D^{0} \bar K^{0}$

abstract:
  Rare decay modes $J/\psi \to D_{S}^{-} \pi^{+} + c.c.$, $J/\psi \to D^{-}
\pi^{+} + c.c.$, and $J/\psi \to \bar D^{0} \bar K^{0} + c.c.$ are searched for
using 5.77$\times 10^{7}$ $J/\psi$ events collected with the BESII detector at
the BEPC. No signal above background is observed. We present upper limits on
the branching fractions $B(J/\psi \to D_{S}^{-} \pi^{+})$ $<$
1.4$\times10^{-4}$, $B(J/\psi \to D^{-} \pi^{+})$ $<7.5\times10^{-5}$, and
$B(J/\psi \to \bar D^{0} \bar K^{0})$ $<$ 1.7$\times10^{-4}$ at the 90%
confidence level.


title:
Spin effects in $p\bar p$ interaction and their possible use to polarize
  antiproton beams

abstract:
  Low energy $p\bar p$ interaction is considered taking into account the
polarization of both particles. The corresponding cross sections are calculated
using the Paris nucleon-antinucleon optical potential. Then they are applied to
the analysis of the polarization buildup which is due to the interaction of
stored antiprotons with polarized protons of a hydrogen target. It is shown
that, at realistic parameters of a storage ring and a target, the filtering
mechanism provides a noticeable polarization in a time comparable with the beam
lifetime.


title:
Relation between three-qubit entanglement invariants and two-qubit
  concurrence

abstract:
  In this Brief Report we show the relation between three-qubit entanglement
invariants and two-qubit concurrence with the help of projective measurements.
How to use these invariants to represent the entanglement property of
three-qubit pure states is also investigated.


title: The asymptotic limits of zero modes of massless Dirac operators

abstract:
  Asymptotic behaviors of zero modes of the massless Dirac operator
$H=\alpha\cdot D + Q(x)$ are discussed, where
  $\alpha= (\alpha_1, \alpha_2, \alpha_3)$ is the triple of $4 \times 4$ Dirac
matrices, $ D=\frac{1}{i} \nabla_x$, and $Q(x)=\big(q_{jk} (x) \big)$ is a
$4\times 4$ Hermitian matrix-valued function with
  $| q_{jk}(x) | \le C < x >^{-\rho} $, $\rho >1$.
  We shall show that for every zero mode $f$, the asymptotic limit of
$|x|^2f(x)$ as $|x| \to +\infty$ exists. The limit is expressed in terms of an
integral of $Q(x)f(x)$.


title: Is CHF triggered by the vapor recoil effect?

abstract:
  This paper deals with the triggering mechanism of the boiling crisis, a
transition from nucleate to film boiling. We observe the boiling crisis in pool
saturated boiling experimentally at nearly critical pressure to take advantage
of the slowness of the bubble growth and of the smallness of the Critical Heat
Flux (CHF) that defines the transition point. Such experiments require the
reduced gravity conditions. Close to the CHF, the slow growth of the individual
dry spots and their subsequent fusion on the transparent heater are observed
through the latter. As discussed in the paper, these observations are
consistent with numerical results obtained with the vapor recoil model of the
boiling crisis.


title:
Gale duality bounds for roots of polynomials with nonnegative
  coefficients

abstract:
  We bound the location of roots of polynomials that have nonnegative
coefficients with respect to a fixed but arbitrary basis of the vector space of
polynomials of degree at most $d$. For this, we interpret the basis polynomials
as vector fields in the real plane, and at each point in the plane analyze the
combinatorics of the Gale dual vector configuration. This approach permits us
to incorporate arbitrary linear equations and inequalities among the
coefficients in a unified manner to obtain more precise bounds on the location
of roots. We apply our technique to bound the location of roots of Ehrhart and
chromatic polynomials. Finally, we give an explanation for the clustering seen
in plots of roots of random polynomials.


title:
Far UV excitation of hydrogen and light emission; applications in
  astrophysics

abstract:
  Assuming a spherical symmetry, the extreme UV emitted by a very hot source
ionizes low pressure molecular hydrogen making a transparent bubble of H II
(Protons and electrons). For an increase of radius, intensity of extreme UV and
temperature decrease, so that the plasma contains more and more atoms. A
spherical shell, mainly of neutral atoms (H I) appears. If this shell is
optically thick at Lyman frequencies of H I, it is superradiant and a
competition of modes selects modes tangent to a sphere for which many atoms are
excited. Thus, a shell of plasma emits, into a given direction, tangential rays
showing a ring in which selected modes are brighter. While at Lyman
frequencies, absorption of rays emitted by the source excites the atoms able to
amplify the superradiance, a more powerful amplification of superradiance
results from an induced scattering of the radial beams, which extends to feet
of lines and progressively to the whole spectrum. Thermodynamics says that the
brightness of radial and tangential beams tends to be equal; if the solid angle
of observation is much larger for the ring than for the source, almost the
whole light emitted by the source is transferred to the rings, and the source
becomes invisible. Paradoxically, a glow due to incoherent scattering and
impurities around the source remains visible. As the scattering decreases with
the decrease of the radial intensity, the brightness of the ring decreases with
radius. These characteristics are found in supernova remnant 1987A.


title:
Chaotic flows and cosmic dynamos in anisotropic pseudo-Riemannian
  four-dimensional spacetime

abstract:
  It is shown that the existence of the cosmic kinematic fast dynamos in
Bianchi type IX rotating cosmological models, faces severe difficulties, due to
the fact that in these models rotation increases without bounds, which is
strictly forbidden by CMB astronomical date which imposes strong bounds on its
rotation with respect with its rapid expansion. The only way out of this
difficulty is to assume that at least one of the expansion directions of this
anisotropic universe decays as fast as the amplification rate of primordial
magnetic fields. A solution is found where only one direction of the
anisotropic universe expands while the other two remain constants. We compute
an amplification of the seed magnetic field in the case where Bianchi IX
degenerates into de Sitter metric, fields amplify from 10^{-6}G to 10^{-5}G in
spiral galaxies for a cosmological constant of the order
$|{\Lambda}|<10^{33}s^{-2}$ and considering that the age of universe of the
order of 10^{10}yrs. Another example is given by the ABC chaotic flows in the
pseudo-Riemannian spacetime representing the Kasner anisotropic nonsingular
universe.


title:
Application of probabilistic PCR5 Fusion Rule for Multisensor Target
  Tracking

abstract:
  This paper defines and implements a non-Bayesian fusion rule for combining
densities of probabilities estimated by local (non-linear) filters for tracking
a moving target by passive sensors. This rule is the restriction to a strict
probabilistic paradigm of the recent and efficient Proportional Conflict
Redistribution rule no 5 (PCR5) developed in the DSmT framework for fusing
basic belief assignments. A sampling method for probabilistic PCR5 (p-PCR5) is
defined. It is shown that p-PCR5 is more robust to an erroneous modeling and
allows to keep the modes of local densities and preserve as much as possible
the whole information inherent to each densities to combine. In particular,
p-PCR5 is able of maintaining multiple hypotheses/modes after fusion, when the
hypotheses are too distant in regards to their deviations. This new p-PCR5 rule
has been tested on a simple example of distributed non-linear filtering
application to show the interest of such approach for future developments. The
non-linear distributed filter is implemented through a basic particles
filtering technique. The results obtained in our simulations show the ability
of this p-PCR5-based filter to track the target even when the models are not
well consistent in regards to the initialization and real cinematic.


title:
Situations d'apprentissage collectives instrument\'ees : \'etude de
  pratiques dans l'enseignement sup\'erieur

abstract:
  Currently, educational platforms propose many tools of communication,
production, labour division or collective work management in order to support
collective activities. But it is not guaranteed that actors (instructional
designers, tutors or learner) are really using them. Our work, describe
characteristics of instrumented learning situations (ICLS) in the higher
education. Our intention is to determine: if ICLS are really existing; which
form they take (in terms of scenario, tools, type of activity...) ; if
recommendations resulting from research tasks are taken into account by
instructional designers and if the instructional designer prescribed activities
are really follow by learners or tutors? To answer these questions, we have
made a survey about ICLS actors uses.


title:
Application of Glow Discharge Aes for Investigation of Metal Ions and
  Water in Biology and Medicine

abstract:
  AES VHF inductively coupled plasmatron may be applied to wide range of
studies. It enables rapid microanalysis of various solutions including
biological objects and peripheral blood serum. In addition, it may be used for
investigation of water desorption from solid bodies and for determination of
energetic metal-macromolecule complexes. Study of hydration energy and
hydration number by kinetic curves of water glow discharge atomic spectral
analysis of hydrogen (GD EAS analysis of hydrogen) desorption from Na-DNA
humidified fibers allowed to reveal that structural and conformational changes
in activation energy of hydrated water molecules increases by 0.65kcal/Mole of
water. The developed method of analysis of elements in solutions containing
high concentrations of organic materials allows systematic study of practically
healthy persons and reveals risk factors for several diseases. Microelemental
content of blood serum fractions showed that amount of not bounded with
ceruloplasmin copper was three times more at limphogranulomatose disease than
that in healthy persons.


title: Super-resolution in turbulent videos: making profit from damage

abstract:
  It is shown that one can make use of local instabilities in turbulent video
frames to enhance image resolution beyond the limit defined by the image
sampling rate. The paper outlines the processing algorithm, presents its
experimental verification on simulated and real-life videos and discusses its
potentials and limitations.


title:
Diamagnetism of doped two-leg ladders and probing the nature of their
  commensurate phases

abstract:
  We study the magnetic orbital effect of a doped two-leg ladder in the
presence of a magnetic field component perpendicular to the ladder plane.
Combining both low-energy approach (bosonization) and numerical simulations
(density-matrix renormalization group) on the strong coupling limit (t-J
model), a rich phase diagram is established as a function of hole doping and
magnetic flux. Above a critical flux, the spin gap is destroyed and a Luttinger
liquid phase is stabilized. Above a second critical flux, a reentrance of the
spin gap at high magnetic flux is found. Interestingly, the phase transitions
are associated with a change of sign of the orbital susceptibility. Focusing on
the small magnetic field regime, the spin-gapped superconducting phase is
robust but immediately acquires algebraic transverse (i.e. along rungs) current
correlations which are commensurate with the 4k_F density correlations. In
addition, we have computed the zero-field orbital susceptibility for a large
range of doping and interactions ratio J/t : we found strong anomalies at low
J/t only in the vicinity of the commensurate fillings corresponding to delta =
1/4 and 1/2. Furthermore, the behavior of the orbital susceptibility reveals
that the nature of these insulating phases is different: while for delta = 1/4
a 4k_F charge density wave is confirmed, the delta = 1/2 phase is shown to be a
bond order wave.