title:
Measuring Singularity of Generalized Minimizers for Control-Affine
  Problems

abstract:
  An open question contributed by Yu. Orlov to a recently published volume
"Unsolved Problems in Mathematical Systems and Control Theory", V.D. Blondel,
A. Megretski (eds), Princeton Univ. Press, 2004, concerns regularization of
optimal control-affine problems. These noncoercive problems in general admit
'cheap (generalized) controls' as minimizers; it has been questioned whether
and under what conditions infima of the regularized problems converge to the
infimum of the original problem. Starting with a study of this question we show
by simple functional-theoretic reasoning that it admits, in general, positive
answer. This answer does not depend on commutativity/noncommtativity of
controlled vector fields. It depends instead on presence or absence of a
Lavrentiev gap.
  We set an alternative question of measuring "singularity" of minimizing
sequences for control-affine optimal control problems by so-called degree of
singularity. It is shown that, in the particular case of singular
linear-quadratic problems, this degree is tightly related to the "order of
singularity" of the problem. We formulate a similar question for nonlinear
control-affine problem and establish partial results. Some conjectures and open
questions are formulated.


title: Chemical Abundances from the Continuum

abstract:
  The calculation of solar absolute fluxes in the near-UV is revisited,
discussing in some detail recent updates in theoretical calculations of
bound-free opacity from metals. Modest changes in the abundances of elements
such as Mg and the iron-peak elements have a significant impact on the
atmospheric structure, and therefore self-consistent calculations are
necessary. With small adjustments to the solar photospheric composition, we are
able to reproduce fairly well the observed solar fluxes between 200 and 270 nm,
and between 300 and 420 nm, but find too much absorption in the 270-290 nm
window. A comparison between our reference 1D model and a 3D time-dependent
hydrodynamical simulation indicates that the continuum flux is only weakly
sensitive to 3D effects, with corrections reaching <10% in the near-UV, and <2%
in the optical.


title: Controlling Multiparticle System on a Line. I

abstract:
  We study a classical multiparticle system (such as Toda lattice) whose
dynamics we intend to control by forces applied to few particles of the system.
Various problem settings, typical for control theory are posed for this model;
among those: studying accessibility and controllability properties, structure
properties and feedback linearization of respective control system,
time-optimal relocation of particles. We obtain complete or partial answers to
the posed questions; criteria and methods of geometric control theory are
employed. In the present part I we consider nonperiodic multiparticle system.
In the forthcoming Part II we address controllability issue for multiparticle
system subject to periodic boundary conditions. That study would require an
extension and refinement of known methods of geometric control.


title: Electroweak Theory for the Tevatron, LHC, and ILC

abstract:
  Future high precision electroweak measurements require understanding of
Standard Model expectations to multi-loop accuracy, both, for the predictions
of production cross-sections of signal and background, as well as for
pseudo-observables. I review recent results from precision calculations and
summarize projections and implications for the Tevatron, the LHC, CEBAF, and
the ILC.


title: Muon decay in a laser field

abstract:
  We investigate the change in the decay rate of a muon caused by embedding it
in the field of a laser. A previous paper found that the change could be large,
as much as an order of magnitude. We find the more intuitive result that the
change is small and give analytic expressions for the small corrections.


title: Zernike Basis to Cartesian Transformations

abstract:
  The radial polynomials of the 2D (circular) and 3D (spherical) Zernike
functions are tabulated as powers of the radial distance. The reciprocal
tabulation of powers of the radial distance in series of radial polynomials is
also given, based on projections that take advantage of the orthogonality of
the polynomials over the unit interval. They may play a role in the expansion
of products of the polynomials into sums, which is demonstrated by some
examples. Multiplication of the polynomials by the angular bases (azimuth,
polar angle) defines the Zernike functions, for which we derive and tabulate
transformations to and from the Cartesian coordinate system centered at the
middle of the circle or sphere.


title: Slices of the Kerr ergosurface

abstract:
  The intrinsic geometry of the Kerr ergosurface on constant Boyer-Lindquist
(BL), Kerr, and Doran time slices is characterized. Unlike the BL slice, which
had been previously studied, the other slices (i) do not have conical
singularities at the poles (except the Doran slice in the extremal limit), (ii)
have finite polar circumference in the extremal limit, and (iii) for
sufficiently large spin parameter fail to be isometrically embeddable as a
surface of revolution above some latitude. The Doran slice develops an
embeddable polar cap for spin parameters greater than about 0.96.

categories: gr-qc astro-ph hep-th math-ph math.DG math.MP


title: Discovery in IC10 of the farthest known symbiotic star

abstract:
  We report the discovery of the first known symbiotic star in IC10, a
starburst galaxy belonging to the Local Group, at a distance of ~750kpc. The
symbiotic star was identified during a survey of emission-line objects. It
shines at V = 24.62+-0.04, V - R_C = 2.77+-0.05 and R_C - I_C = 2.39+-0.02 and
suffers from E(B-V) = 0.85+-0.05 reddening. The spectrum of the cool component
well matches that of solar neighborhood M8III giants. The observed emission
lines belong to Balmer series, [SII], [NII] and [OIII]. They suggest a low
electronic density, negligible optical depth effects and 35,000K < T_eff <
90,000K for the ionizing source. The spectrum of the new symbiotic star in IC10
is an almost perfect copy of that of Hen 2-147, a well known Galactic symbiotic
star and Mira.


title: Relic density in SO(10) SUSY GUT models

abstract:
  Non-universal boundary conditions in grand unified theories can lead to
non-universal gaugino masses at the unification scale. In R-parity preserving
theories the lightest supersymmetric particle is a natural candidate for the
dark matter. In this talk the composition of the lightest neutralino is
studied, when nonuniversal gaugino masses come from representations of SO(10).
In these cases, the thermal relic density compatible with WMAP observations is
found.


title: Future Antiproton Experiments at Fermilab

abstract:
  Fermilab operates the world's most intense antiproton source. Newly proposed
experiments can use those antiprotons either parasitically during Tevatron
Collider running or after the Tevatron Collider finishes in about 2010. In
particular, the annihilation of 8 GeV antiprotons might make the world's most
intense source of tagged $D^0$ mesons, and thus the best near-term opportunity
to study charm mixing and, via CP violation, to search for new physics; a
Penning trap and atom interferometer could be used to measure for the first
time the gravitational force on antimatter.


title: Mapping stacks of topological stacks

abstract:
  We prove that the mapping stack Map(Y,X) of topological stacks X and Y is
again a topological stack if Y admits a compact groupoid presentation. If Y
admits a locally compact groupoid presentation, we show that Map(Y,X) is a
paratopological stack. In particular, it has a classifying space (hence, a
natural weak homotopy type). We prove an invariance theorem which shows that
the weak homotopy type of the mapping stack Map(Y,X) does not change if we
replace X by its classifying space, provided that Y is paracompact topological
space. As an example, we describe the loop stack of the classifying stack BG of
a topological group G in terms of twisted loop groups of G.


title: Permutations with Kazhdan-Lusztig polynomial P_{id,w}(q) = 1 + q^h

abstract:
  Using resolutions of singularities introduced by Cortez and a method for
calculating Kazhdan-Lusztig polynomials due to Polo, we prove the conjecture of
Billey and Braden characterizing permutations w with Kazhdan-Lusztig polynomial
P_{id,w}(q)=1+q^h for some h.


title:
Multiplexed Multi-Color Raman Imaging of Live Cells with Isotopically
  Modified Single Walled Carbon Nanotubes

abstract:
  We show that single walled carbon nanotubes with different isotope
compositions exhibit distinct Raman Gband peaks and can be used for multiplexed
multi-color Raman imaging of biological systems. Cancer cells with specific
receptors are selectively labeled with 3 differently colored SWNTs conjugated
with various targeting ligands including Herceptin, anti-Her2, Erbitux,
anti-Her1, and RGD peptide, allowing for multi-color Raman imaging of cells in
a multiplexed manner. SWNT Raman signals are highly robust against
photo-bleaching, allowing long term imaging and tracking. With narrow peak
features, SWNT Raman signals are easily differentiated from the
auto-fluorescence background. The SWNT Raman excitation and scattering photons
are in the near-infrared region, which is the most transparent optical window
for biological systems in vitro and in vivo. Thus, SWNTs are novel Raman tags
promising for multiplexed biological detection and imaging.


title: Quantum State Tomography: 'the best' is the enemy of 'good enough'

abstract:
  In this paper, we examine a variety of strategies for numerical quantum-state
estimation from data of the sort commonly measured in experiments involving
quantum state tomography. We find that, in some important circumstances, an
elaborate and time-consuming numerical optimization to obtain 'the best'
density matrix corresponding to a given data set is not necessary, and that
cruder, faster numerical techniques may well be 'good enough'.


title: Propagation of Exchange Bias in CoFe/FeMn/CoFe Trilayers

abstract:
  CoFe/FeMn, FeMn/CoFe bilayers and CoFe/FeMn/CoFe trilayers were grown in
magnetic field and at room temperature. The exchange bias field $H_{eb}$
depends strongly on the order of depositions and is much higher at CoFe/FeMn
than at FeMn/CoFe interfaces. By combining the two bilayer structures into
symmetric CoFe/FeMn($t_\mathrm{FeMn}$)/CoFe trilayers, $H_{eb}^t$ and
$H_{eb}^b$ of the top and bottom CoFe layers, respectively, are both enhanced.
Reducing $t_\mathrm{FeMn}$ of the trilayers also results in enhancements of
both $H_{eb}^b$ and $H_{eb}^t$. These results evidence the propagation of
exchange bias between the two CoFe/FeMn and FeMn/CoFe interfaces mediated by
the FeMn antiferromagnetic order.


title: Testing Linear-Invariant Non-Linear Properties

abstract:
  We consider the task of testing properties of Boolean functions that are
invariant under linear transformations of the Boolean cube. Previous work in
property testing, including the linearity test and the test for Reed-Muller
codes, has mostly focused on such tasks for linear properties. The one
exception is a test due to Green for "triangle freeness": a function
$f:\cube^{n}\to\cube$ satisfies this property if $f(x),f(y),f(x+y)$ do not all
equal 1, for any pair $x,y\in\cube^{n}$.
  Here we extend this test to a more systematic study of testing for
linear-invariant non-linear properties. We consider properties that are
described by a single forbidden pattern (and its linear transformations), i.e.,
a property is given by $k$ points $v_{1},...,v_{k}\in\cube^{k}$ and
$f:\cube^{n}\to\cube$ satisfies the property that if for all linear maps
$L:\cube^{k}\to\cube^{n}$ it is the case that $f(L(v_{1})),...,f(L(v_{k}))$ do
not all equal 1. We show that this property is testable if the underlying
matroid specified by $v_{1},...,v_{k}$ is a graphic matroid. This extends
Green's result to an infinite class of new properties.
  Our techniques extend those of Green and in particular we establish a link
between the notion of "1-complexity linear systems" of Green and Tao, and
graphic matroids, to derive the results.


title: The theory of relativity and the Pythagorean theorem

abstract:
  It is shown that the most important effects of special and general theory of
relativity can be understood in a simple and straightforward way. The system of
units in which the speed of light $c$ is the unit of velocity allows to cast
all formulas in a very simple form.The Pythagorean theorem graphically relates
energy, momentum and mass. The paper is addressed to those who teach and
popularize the theory of relativity.


title: Homotopy Inner Products for Cyclic Operads

abstract:
  We introduce the notion of homotopy inner products for any cyclic quadratic
Koszul operad $\mathcal O$, generalizing the construction already known for the
associative operad. This is done by defining a colored operad
$\widehat{\mathcal O}$, which describes modules over $\mathcal O$ with
invariant inner products. We show that $\widehat{\mathcal O}$ satisfies
Koszulness and identify algebras over a resolution of $\widehat{\mathcal O}$ in
terms of derivations and module maps. As an application we construct a homotopy
inner product over the commutative operad on the cochains of any Poincar\'e
duality space.


title:
Phase transitions in systems of magnetic dipoles on a square lattice
  with quenched disorder

abstract:
  We study by Monte Carlo simulations the effect of quenched orientational
disorder in systems of interacting classical dipoles on a square lattice. Each
dipole can lie along any of two perpendicular axes that form an angle psi with
the principal axes of the lattice. We choose psi at random and without bias
from the interval [-Delta, Delta] for each site of the lattice. For 0<Delta <~
pi/4 we find a thermally driven second order transition between a paramagnetic
and a dipolar antiferromagnetic order phase and critical exponents that change
continously with Delta. Near the case of maximum disorder Delta ~ \pi/4 we
still find a second order transition at a finite temperature T_c but our
results point to weak instead of {\it strong} long-ranged dipolar order for
temperatures below T_c.


title: Effects of the $g$-factor in semi-classical kinetic plasma theory

abstract:
  A kinetic theory for spin plasmas is put forward, generalizing those of
previous authors. In the model, the ordinary phase space is extended to include
the spin degrees of freedom. Together with Maxwell's equations, the system is
shown to be energy conserving. Analysing the linear properties, it is found
that new types of wave-particle resonances are possible, that depend directly
on the anomalous magnetic moment of the electron. As a result new wave modes,
not present in the absence of spin, appear. The implications of our results are
discussed.


title: Zero-temperature Phase Diagram of Two Dimensional Hubbard Model

abstract:
  We investigate the two-dimensional Hubbard model on the triangular lattice
with anisotropic hopping integrals at half filling. By means of a self-energy
functional approach, we discuss how stable the non-magnetic state is against
magnetically ordered states in the system. We present the zero-temperature
phase diagram, where the normal metallic state competes with magnetically
ordered states with $(\pi, \pi)$ and $(2\pi/3, 2\pi/3)$ structures. It is shown
that a non-magnetic Mott insulating state is not realized as the ground state,
in the present framework, but as a meta-stable state near the magnetically
ordered phase with $(2\pi/3, 2\pi/3)$ structure.


title:
Influences of degree inhomogeneity on average path length and random
  walks in disassortative scale-free networks

abstract:
  Various real-life networks exhibit degree correlations and heterogeneous
structure, with the latter being characterized by power-law degree distribution
$P(k)\sim k^{-\gamma}$, where the degree exponent $\gamma$ describes the extent
of heterogeneity. In this paper, we study analytically the average path length
(APL) of and random walks (RWs) on a family of deterministic networks,
recursive scale-free trees (RSFTs), with negative degree correlations and
various $\gamma \in (2,1+\frac{\ln 3}{\ln 2}]$, with an aim to explore the
impacts of structure heterogeneity on APL and RWs. We show that the degree
exponent $\gamma$ has no effect on APL $d$ of RSFTs: In the full range of
$\gamma$, $d$ behaves as a logarithmic scaling with the number of network nodes
$N$ (i.e. $d \sim \ln N$), which is in sharp contrast to the well-known double
logarithmic scaling ($d \sim \ln \ln N$) previously obtained for uncorrelated
scale-free networks with $2 \leq \gamma <3$. In addition, we present that some
scaling efficiency exponents of random walks are reliant on degree exponent
$\gamma$.


title: Exotic automorphisms of the Schouten algebra of polyvector fields

abstract:
  Using a new compactification of the (braid) configuration space of n points
in the upper half plane we construct a family of exotic Lie-infinity
automorphisms of the Schouten algebra of polyvector fields on an affine space
depending on a Kontsevich type propagator.


title: Datalog and Constraint Satisfaction with Infinite Templates

abstract:
  On finite structures, there is a well-known connection between the expressive
power of Datalog, finite variable logics, the existential pebble game, and
bounded hypertree duality. We study this connection for infinite structures.
This has applications for constraint satisfaction with infinite templates. If
the template Gamma is omega-categorical, we present various equivalent
characterizations of those Gamma such that the constraint satisfaction problem
(CSP) for Gamma can be solved by a Datalog program. We also show that
CSP(Gamma) can be solved in polynomial time for arbitrary omega-categorical
structures Gamma if the input is restricted to instances of bounded treewidth.
Finally, we characterize those omega-categorical templates whose CSP has
Datalog width 1, and those whose CSP has strict Datalog width k.


title:
Absence of Anomalous Tunneling of Bogoliubov Excitations for Arbitrary
  Potential Barrier under the Critical Condensate Current

abstract:
  We derive the exact solution of low energy limit of Bogoliubov equations for
excitations of Bose-Einstein condensate in the presence of arbitrary potential
barrier and maximum current of condensate. Using this solution, we give the
explicit expression for the transmission coefficient against the potential
barrier, which shows partial transmission in the low energy limit. The
wavefunctions of excitations in the low energy limit do not coincide with that
of the condensate. The absence of the perfect transmission in the critical
current state originates from local enhancement of density fluctuations around
the potential barrier.


title:
Modulation control and spectral shaping of optical fiber supercontinuum
  generation in the picosecond regime

abstract:
  Numerical simulations are used to study how fiber supercontinuum generation
seeded by picosecond pulses can be actively controlled through the use of input
pulse modulation. By carrying out multiple simulations in the presence of
noise, we show how tailored supercontinuum Spectra with increased bandwidth and
improved stability can be generated using an input envelope modulation of
appropriate frequency and depth. The results are discussed in terms of the
non-linear propagation dynamics and pump depletion.


title: PAH emission from Herbig AeBe stars

abstract:
  We present spectra of a sample of Herbig Ae and Be (HAeBe) stars obtained
with the Infrared Spectrograph on the Spitzer Space Telescope. All but one of
the Herbig stars show emission from polycyclic aromatic hydrocarbons (PAHs) and
seven of the spectra show PAH emission, but no silicate emission at 10 microns.
The central wavelengths of the 6.2, 7.7--8.2, and 11.3 micron emission features
decrease with stellar temperature, indicating that the PAHs are less
photo-processed in cooler radiation fields. The apparent low level of photo
processing in HAeBe stars, relative to other PAH emission sources, implies that
the PAHs are newly exposed to the UV-optical radiation fields from their host
stars. HAeBe stars show a variety of PAH emission intensities and ionization
fractions, but a narrow range of PAH spectral classifications based on
positions of major PAH feature centers. This may indicate that, regardless of
their locations relative to the stars, the PAH molecules are altered by the
same physical processes in the proto-planetary disks of intermediate-mass
stars. Analysis of the mid-IR spectral energy distributions indicates that our
sample likely includes both radially flared and more flattened/settled disk
systems, but we do not see the expected correlation of overall PAH emission
with disk geometry. We suggest that the strength of PAH emission from HAeBe
stars may depend not only on the degree of radial flaring, but also on the
abundance of PAHs in illuminated regions of the disks and possibly on the
vertical structure of the inner disk as well.


title: A search for super-large structures in deep galaxy surveys

abstract:
  Recent extensive, multi-color deep surveys of galaxies open a possibility to
get observational estimation of sizes for the largest structures in the
Universe. Photometric redshift accuracy (about 0.03(1+z)) allows directly study
clustering at scales about 1000 Mpc. Thanks to large number of galaxies in each
redshift bin one may detect super-large structures if they really exist. Here
we show that the observed behavior of the redshift distribution of galaxies in
deep surveys such as HUDF and FDF is consistent with existence of super-large
structures of luminous matter with scales about 2000 Mpc. We detect a large
underdense region in radial galaxy distribution at redshift interval z=1.2 -
2.2 which separate our "Local Hubble Volume" from the neighboring over-density
region at z=2.2 - 3.5. This result can also explain the observed deficiency of
gamma ray sources at redshift about 2. Observational test on the reality of the
supper-large structures may be obtained by organizing sky covering net (cells
about 10n x 10n degrees) of very deep narrow angle (1n x 1n arc-minutes)
multi-band photometric surveys of galaxies which is achievable for large
ground-based telescopes.


title:
Convergence of diagonal Pad\'e approximants for a class of definitizable
  functions

abstract:
  Convergence of diagonal Pad\'e approximants is studied for a class of
functions which admit the integral representation $ {\mathfrak
F}(\lambda)=r_1(\lambda)\int_{-1}^1\frac{td\sigma(t)}{t-\lambda}+r_2(\lambda),
$ where $\sigma$ is a finite nonnegative measure on $[-1,1]$, $r_1$, $r_2$ are
real rational functions bounded at $\infty$, and $r_1$ is nonnegative for real
$\lambda$. Sufficient conditions for the convergence of a subsequence of
diagonal Pad\'e approximants of $ {\mathfrak F}$ on $\dR\setminus[-1,1]$ are
found. Moreover, in the case when $r_1\equiv 1$, $r_2\equiv 0$ and $\sigma$ has
a gap $(\alpha,\beta)$ containing 0, it turns out that this subsequence
converges in the gap. The proofs are based on the operator representation of
diagonal Pad\'e approximants of $ {\mathfrak F}$ in terms of the so-called
generalized Jacobi matrix associated with the asymptotic expansion of $
{\mathfrak F}$ at infinity.


title: Littlewood--Richardson coefficients and integrable tilings

abstract:
  We provide direct proofs of product and coproduct formulae for Schur
functions where the coefficients (Littlewood--Richardson coefficients) are
defined as counting puzzles. The product formula includes a second alphabet for
the Schur functions, allowing in particular to recover formulae of
[Molev--Sagan '99] and [Knutson--Tao '03] for factorial Schur functions. The
method is based on the quantum integrability of the underlying tiling model.


title:
Explicit tensor network representation for the ground states of
  string-net models

abstract:
  The structure of string-net lattice models, relevant as examples of
topological phases, leads to a remarkably simple way of expressing their ground
states as a tensor network constructed from the basic data of the underlying
tensor categories. The construction highlights the importance of the fat
lattice to understand these models.


title: Structures de r\'ealisabilit\'e, RAM et ultrafiltre sur N

abstract:
  We show how to transform into programs the proofs in classical Analysis which
use the existence of an ultrafilter on the integers. The method mixes the
classical realizability introduced by the author, with the "forcing" of P.
Cohen. The programs we obtain, use read and write instructions in random access
memory.


title: How To Determine SUSY Mass Scales Now

abstract:
  Currently available experimental data from electroweak precision observables
(EWPO), B-physics observables (BPO) and cosmological data can be combined to
extract the preferred value of SUSY mass scales. We review recent results on
the predictions of the masses of supersymmetric particles and the indirect
determination of the lightest Higgs boson mass. Special emphasis is put on
models going beyond the Constrained Minimal Supersymmetric Standard Model
(CMSSM), such as the Non-Universal Higgs Model type I (NUHM1), or gauge and
anomaloy mediated SUSY breaking.


title: Discovery Reach of Charged MSSM Higgs Bosons at CMS

abstract:
  We review the 5 sigma discovery contours for the charged MSSM Higgs boson at
the CMS experiment with 30/fb for the two cases M_H+ < m_t and M_H+ > m_t. In
order to analyze the search reach we combine the latest results for the CMS
experimental sensitivities based on full simulation studies with
state-of-the-art theoretical predictions of MSSM Higgs-boson production and
decay properties. Special emphasis is put on the SUSY parameter dependence of
the 5 sigma contours. The variation of $\mu$ can shift the prospective
discovery reach in tan_beta by up to Delta tan_beta = 40.


title: Selecting Finite Unified Theories with Current Data

abstract:
  Finite Unified Theories (FUTs) are N=1 supersymmetric Grand Unified Theories
that can be made all-loop finite, leading to a severe reduction of the free
parameters. We review the investigation of FUTs based on SU(5) in the context
of low-energy phenomenology observables. Using the restrictions from the top
and bottom quark masses, it is possible to discriminate between different
models. Including further low-energy constraints such as B-physics observables,
the bound on the lightest Higgs boson mass and the cold dark matter density, we
derive the predictions for the supersymmetric particle spectrum and the
prospects for discoveries at the LHC.


title:
Interplay between couplings and common noise in phase synchronization:
  disagreement between global analysis and local stability characterization

abstract:
  We consider two coupled phase oscillators in the presence of proportional
("common") and independent white noises. The global synchronization properties
of the system are analytically studied via the Fokker-Planck equation. When the
"effective coupling" is big compared to the common noises, the former favors
and the latter hinder synchronization. On the contrary, when the coupling is
small compared to the proportional noises, we find that the latter induce
synchronization, optimally when their intensities are big and in the n:m
synchronization ratio. Furthermore, in such case a small value of the coupling
is better for synchronization. Finally, we show that synchronization, which is
a global property, must not be studied via local stability such as with
Lyapunov exponents.


title:
Coupled Painlev\'e systems in dimension four with affine Weyl group
  symmetry of types $A_4^{(2)}$ and $A_1^{(1)}$

abstract:
  We find a two-parameter family of coupled Painlev\'e systems in dimension
four with affine Weyl group symmetry of type $A_4^{(2)}$. For a degenerate
system of $A_4^{(2)}$ system, we also find a one-parameter family of coupled
Painlev\'e systems in dimension four with affine Weyl group symmetry of type
$A_1^{(1)}$. We show that for each system, we give its symmetry and holomorphy
conditions. These symmetries, holomorphy conditions and invariant divisors are
new. Moreover, we find a one-parameter family of partial differential systems
in three variables with $W(A_1^{(1)})$-symmetry. We show the relation between
its polynomial Hamiltonian system and an autonomous version of the system of
type $A_1^{(1)}$.


title: Modeling pulse profiles of accreting millisecond pulsars

abstract:
  I review the basic observational properties of accreting millisecond pulsars
that are important for understanding the physics involved in formation of their
pulse profiles. I then discuss main effects responsible for shaping these
profiles. Some analytical results that help to understand the results of
simulations are presented. Constraints on the pulsar geometry and the neutron
star equation of state obtained from the analysis of the pulse profiles are
discussed.


title:
Number theoretic techniques in the theory of Lie groups and differential
  geometry

abstract:
  The purpose of this article is to present a survey of our recent results on
length commensurable and isospectral locally symmetric spaces. The geometric
questions led us to the notion of "weak commensurability" of two Zariski-dense
subgroups in a semi-simple Lie group. We have shown that for arithmetic
subgroups, weak commensurability has surprisingly strong consequences. Our
proofs make use of p-adic techniques and results from algebraic and
transcendental number theory.


title:
Estimation of a probability with optimum guaranteed confidence in
  inverse binomial sampling

abstract:
  Sequential estimation of a probability $p$ by means of inverse binomial
sampling is considered. For $\mu_1,\mu_2>1$ given, the accuracy of an estimator
$\hat{p}$ is measured by the confidence level $P[p/\mu_2\leq\hat{p}\leq
p\mu_1]$. The confidence levels $c_0$ that can be guaranteed for $p$ unknown,
that is, such that $P[p/\mu_2\leq \hat{p}\leq p\mu_1]\geq c_0$ for all
$p\in(0,1)$, are investigated. It is shown that within the general class of
randomized or non-randomized estimators based on inverse binomial sampling,
there is a maximum $c_0$ that can be guaranteed for arbitrary $p$. A
non-randomized estimator is given that achieves this maximum guaranteed
confidence under mild conditions on $\mu_1$, $\mu_2$.


title:
A cosmic abundance standard: chemical homogeneity of the solar
  neighbourhood and the ISM dust-phase composition

abstract:
  A representative sample of unevolved early B-type stars in nearby OB
associations and the field is analysed to unprecedented precision using NLTE
techniques. The resulting chemical composition is found to be more metal-rich
and much more homogeneous than indicated by previous work. A rms scatter of
~10% in abundances is found for the six stars (and confirmed by six evolved
stars), the same as reported for ISM gas-phase abundances. A cosmic abundance
standard for the present-day solar neighbourhood is proposed, implying mass
fractions for hydrogen, helium and metals of X=0.715, Y=0.271 and Z=0.014. Good
agreement with solar photospheric abundances as reported from recent 3D
radiative-hydrodynamical simulations of the solar atmosphere is obtained. As a
first application we use the cosmic abundance standard as a proxy for the
determination of the local ISM dust-phase composition, putting tight
observational constraints on dust models.


title: Accretion onto Seed Black Holes in the First Galaxies

abstract:
  The validity of the hypothesis that the massive black holes in high redshift
quasars grew from stellar-sized "seeds" is contingent on a seed's ability to
double its mass every few ten million years. This requires that the seed
accrete at approximately the Eddington-limited rate. In the specific case of
radiatively efficient quasiradial accretion in a metal-poor protogalactic
medium, for which the Bondi accretion rate is often prescribed in cosmological
simulations of massive black hole formation, we examine the effects of the
radiation emitted near the black hole's event horizon on the structure of the
surrounding gas flow. We find that the radiation pressure from photoionization
significantly reduces the steady-state accretion rate and renders the
quasiradial accretion flow unsteady and inefficient. The time-averaged
accretion rates are a small fraction of the Eddington-limited accretion rate
for Thomson scattering. The pressure of Ly-alpha photons trapped near the HII
region surrounding the black hole may further attenuate the inflow. These
results suggest that an alternative to quasiradial, radiatively efficient
Bondi-like accretion should be sought to explain the rapid growth of
quasar-progenitor seed black holes.


title: Stellar Velocity Distribution in Galactic Disks

abstract:
  We present numerical studies of the properties of the stellar velocity
distribution in galactic disks which have developed a saturated, two-armed
spiral structure. In previous papers we used the Boltzmann moment equations
(BME) up to second order for our studies of the velocity structure in
self-gravitating stellar disks. A key assumption of our BME approach is the
zero-heat flux approximation, i.e. the neglection of third order velocity
terms. We tested this assumption by performing test particle simulations for
stars in a disk galaxy subject to a rotating spiral perturbation. As a result
we corroborated qualitatively the complex velocity structure found in the BME
approach. It turned out that an equilibrium configuration in velocity space is
only slowly established on a typical timescale of 5 Gyrs or more. Since many
dynamical processes in galaxies (like the growth of spirals or bars)act on
shorter timescales, pure equilibrium models might not be fully appropriate for
a detailed comparison with observations like the local Galactic velocity
distribution. Third order velocity moments were typically small and
uncorrelated over almost all of the disk with the exception of the 4:1
resonance region (UHR). Near the UHR (normalized) fourth and fifth order
velocity moments are still of the same order as the second and third order
terms. Thus, at the UHR higher order terms are not negligible.


title: A brief note on the spectrum of the basic Dirac operator

abstract:
  In this paper, we prove the invariance of the spectrum of the basic Dirac
operator defined on a Riemannian foliation $(M,\mathcal{F})$ with respect to a
change of bundle-like metric. We then establish new estimates for its
eigenvalues on spin flows in terms of the O'Neill tensor and the first
eigenvalue of the Dirac operator on $M$. We discuss examples and also define a
new version of the basic Laplacian whose spectrum does not depend on the choice
of bundle-like metric.


title:
Implementing Communication-Optimal Parallel and Sequential QR
  Factorizations

abstract:
  We present parallel and sequential dense QR factorization algorithms for tall
and skinny matrices and general rectangular matrices that both minimize
communication, and are as stable as Householder QR. The sequential and parallel
algorithms for tall and skinny matrices lead to significant speedups in
practice over some of the existing algorithms, including LAPACK and ScaLAPACK,
for example up to 6.7x over ScaLAPACK. The parallel algorithm for general
rectangular matrices is estimated to show significant speedups over ScaLAPACK,
up to 22x over ScaLAPACK.


title: Normal automorphisms of relatively hyperbolic groups

abstract:
  An automorphism $\alpha$ of a group $G$ is normal if it fixes every normal
subgroup of $G$ setwise. We give an algebraic description of normal
automorphisms of relatively hyperbolic groups. In particular, we prove that for
any relatively hyperbolic group $G$, $Inn(G)$ has finite index in the subgroup
$Aut_n(G)$ of normal automorphisms. If, in addition, $G$ is non-elementary and
has no non-trivial finite normal subgroups, then $Aut_n(G)=Inn(G)$. As an
application, we show that $Out(G)$ is residually finite for every finitely
generated residually finite group $G$ with more than one end.


title:
Model-independent implications of the e+, e-, anti-proton cosmic ray
  spectra on properties of Dark Matter

abstract:
  Taking into account spins, we classify all two-body non-relativistic Dark
Matter annihilation channels to the allowed polarization states of Standard
Model particles, computing the energy spectra of the stable final-state
particles relevant for indirect DM detection. We study the DM masses,
annihilation channels and cross sections that can reproduce the PAMELA
indications of an e+ excess consistently with the PAMELA p-bar data and the
ATIC/PPB-BETS e++e- data. From the PAMELA data alone, two solutions emerge: (i)
either the DM particles that annihilate into W,Z,h must be heavier than about
10 TeV or (ii) the DM must annihilate only into leptons. Thus in both cases a
DM particle compatible with the PAMELA excess seems to have quite unexpected
properties. The solution (ii) implies a peak in the e++e- energy spectrum,
which, indeed, seems to appear in the ATIC/PPB-BETS data around 700 GeV. If
upcoming data from ATIC-4 and GLAST confirm this feature, this would point to a
O(1) TeV DM annihilating only into leptons. Otherwise the solution (i) would be
favored. We comment on the implications of these results for DM models, direct
DM detection and colliders as well as on the possibility of an astrophysical
origin of the excess.


title: New Developments in MadGraph/MadEvent

abstract:
  We here present some recent developments of MadGraph/MadEvent since the
latest published version, 4.0. These developments include: Jet matching with
Pythia parton showers for both Standard Model and Beyond the Standard Model
processes, decay chain functionality, decay width calculation and decay
simulation, process generation for the Grid, a package for calculation of
quarkonium amplitudes, calculation of Matrix Element weights for experimental
events, automatic dipole subtraction for next-to-leading order calculations,
and an interface to FeynRules, a package for automatic calculation of Feynman
rules and model files from the Lagrangian of any New Physics model.


title:
Structures of the magnetoionic media around the FR I radio galaxies 3C
  31 and Hydra A

abstract:
  We use high-quality VLA images of the Fanaroff & Riley Class I radio galaxy
3C 31 at six frequencies in the range 1365 to 8440MHz to explore the spatial
scale and origin of the rotation measure (RM) fluctuations on the line of sight
to the radio source. We analyse the distribution of the degree of polarization
to show that the large depolarization asymmetry between the North and South
sides of the source seen in earlier work largely disappears as the resolution
is increased. We show that the depolarization seen at low resolution results
primarily from unresolved gradients in a Faraday screen in front of the
synchrotron-emitting plasma. We establish that the residual degree of
polarization in the short-wavelength limit should follow a Burn law and we fit
such a law to our data to estimate the residual depolarization at high
resolution. We show that the observed RM variations over selected areas of 3C
31 are consistent with a power spectrum of magnetic fluctuations in front of 3C
31 whose power-law slope changes significantly on the scales sampled by our
data. The power spectrum can only have the form expected for Kolmogorov
turbulence on scales <5 kpc. On larger scales we find a flatter slope. We also
compare the global variations of RM across 3C 31 with the results of
three-dimensional simulations of the magnetic-field fluctuations in the
surrounding magnetoionic medium. We show that our data are consistent with a
field distribution that favours the plane perpendicular to the jet axis -
probably because the radio source has evacuated a large cavity in the
surrounding medium. We also apply our analysis techniques to the case of Hydra
A, where the shape and the size of the cavities produced by the source in the
surrounding medium are known from X-ray data. (Abridged)


title: Bianchi I with variable $G$ and $\Lambda$. Self-Similar approach

abstract:
  In this paper we study how to attack under the self-similarity hypothesis a
perfect fluid Bianchi I model with variable $G,$and $\Lambda,$ but under the
condition $\operatorname{div}T\neq0.$ We arrive to the conclusion that: $G$ and
$\Lambda$ are decreasing time functions (the sing of $\Lambda$ depends on the
equation of state), while the exponents of the scale factor must satisfy the
conditions $\sum_{i=1}^{3}\alpha_{i}=1$ and $\sum_{i=1}^{3}\alpha_{i}^{2}<1,$
$\forall\omega\in(-1,1) ,$ relaxing in this way the Kasner conditions. We also
show the connection between the behavior of $G$ and the Weyl tensor.


title: Hydrodynamic view in the NICA energy range

abstract:
  Results for penetrating probes treated within a hybrid hydro-kinetic model
are projected onto the energy range covered by the NICA and FAIR projects. A
new source of dileptons emitted from a mixed quark-hadron phase, quark-hadron
bremsstrahlung, is proposed. An estimate for the $\pi\pi \to\sigma \to
\gamma\gamma$ process in nuclear collisions is given.


title: Shelling Coxeter-like Complexes and Sorting on Trees

abstract:
  In their work on `Coxeter-like complexes', Babson and Reiner introduced a
simplicial complex $\Delta_T$ associated to each tree $T$ on $n$ nodes,
generalizing chessboard complexes and type A Coxeter complexes. They
conjectured that $\Delta_T$ is $(n-b-1)$-connected when the tree has $b$
leaves. We provide a shelling for the $(n-b)$-skeleton of $\Delta_T$, thereby
proving this conjecture.
  In the process, we introduce notions of weak order and inversion functions on
the labellings of a tree $T$ which imply shellability of $\Delta_T$, and we
construct such inversion functions for a large enough class of trees to deduce
the aforementioned conjecture and also recover the shellability of chessboard
complexes $M_{m,n}$ with $n \ge 2m-1$. We also prove that the existence or
nonexistence of an inversion function for a fixed tree governs which networks
with a tree structure admit greedy sorting algorithms by inversion elimination
and provide an inversion function for trees where each vertex has capacity at
least its degree minus one.


title:
Limb preference in the gallop of dogs and the half-bound of pikas on
  flat ground

abstract:
  During fast locomotion - gallop, half bound - of quadruped mammals, the
ground contact of the limbs in each pair do not alternate symmetrically.
Animals using such asymmetrical gait thus choose whether the left or the right
limb will contact the ground first, and this gives rise to limb preference.
Here, we report that dogs (Mammalia, Carnivora) and pikas (Mammalia,
Lagomorpha) prefer one forelimb as trailing limb and use it as such almost
twice as often as the other. We also show that this choice depends on the
individual and is not a characteristic of the species, and that the strength of
the preference was not dependent on the animal's running speed.


title: When efficient star formation drives cluster formation

abstract:
  We investigate the impact of the star formation efficiency in cluster forming
cores on the evolution of the mass in star clusters over the age range
1-100Myr, when star clusters undergo their infant weight-loss/mortality phase.
Assuming a constant formation rate of gas-embedded clusters and a weak tidal
field, we show that the ratio between the total mass in stars bound to the
clusters over that age range and the total mass in stars initially formed in
gas-embedded clusters is a strongly increasing function of the averaged local
SFE, with little influence from any assumed core mass-radius relation. Our
results suggest that, for young starbursts with estimated tidal field strength
and known recent star formation history, observed cluster-to-star mass ratios,
once corrected for the undetected clusters, constitute promising probes of the
local SFE, without the need of resorting to gas mass estimates. Similarly, the
mass ratio of stars which remain in bound clusters at the end of the infant
mortality/weight-loss phase depends sensitively on the mean local SFE, although
the impacts of the width of the SFE distribution function and of the core
mass-radius relation require more careful assessment in this case. Following
the recent finding by Bastian (2008) that galaxies form, on the average, 8% of
their stars in bound clusters regardless of their star formation rate, we raise
the hypothesis that star formation in the present-day Universe is characterized
by a near-universal distribution for the local SFE. A related potential
application of our model consists in tracing the evolution of the local SFE
over cosmological lookback times by comparing the age distribution of the total
mass in star clusters to that in field stars. We describe model aspects which
are still to be worked out before achieving this goal.


title: Effects of dark matter annihilation on the first stars

abstract:
  We study the evolution of the first stars in the universe (Population III)
from the early pre-Main Sequence until the end of helium burning in the
presence of WIMP dark matter annihilation inside the stellar structure. The two
different mechanisms that can provide this energy source are the contemporary
contraction of baryons and dark matter, and the capture of WIMPs by scattering
off the gas with subsequent accumulation inside the star. We find that the
first mechanism can generate an equilibrium phase, previously known as a "dark
star", which is transient and present in the very early stages of pre-MS
evolution. The mechanism of scattering and capture acts later, and can support
the star virtually forever, depending on environmental characteristic of the
dark matter halo and on the specific WIMP model.


title: Enlightening the structure and dynamics of Abell 1942

abstract:
  We present a dynamical analysis of the galaxy cluster Abell 1942 based on a
set of 128 velocities obtained at the European Southern Observatory. Data on
individual galaxies are presented and the accuracy of the determined velocities
is discussed as well as some properties of the cluster. We have also made use
of publicly available Chandra X-ray data. We obtained an improved mean redshift
value z = 0.22513 \pm 0.0008 and velocity dispersion sigma = 908^{+147}_{-139}
km/s. Our analysis indicates that inside a radius of ~1.5 h_{70}^{-1} Mpc (~7
arcmin) the cluster is well relaxed, without any remarkable feature and the
X-ray emission traces fairly well the galaxy distribution. Two possible optical
substructures are seen at ~5 arcmin from the centre towards the Northwest and
the Southwest direction, but are not confirmed by the velocity field. These
clumps are however, kinematically bound to the main structure of Abell 1942.
X-ray spectroscopic analysis of Chandra data resulted in a temperature kT = 5.5
\pm 0.5 keV and metal abundance Z = 0.33 \pm 0.15 Z_odot. The velocity
dispersion corresponding to this temperature using the T_X-sigma scaling
relation is in good agreement with the measured galaxies velocities. Our
photometric redshift analysis suggests that the weak lensing signal observed at
the south of the cluster and previously attributed to a "dark clump", is
produced by background sources, possibly distributed as a filamentary
structure.


title: Magnetic Scenario for the QCD Fluid at RHIC

abstract:
  We present new developments of the "magnetic scenario" for the QCD Fluid
observed at RHIC. The recent lattice data for finite T monopoles are used to
pin down the parameters of the magnetic component of quark-gluon plasma: in
particular we show how the magnetic density and plasma coupling $\Gamma_M$
change with $T$. We then discuss one central issue imposed by the heavy ion
data: i.e. the extremely short dissipation length in the QCD fluid around
$T_c$. We show that the Lorentz trapping effect, present only in a plasma with
both electric and magnetic charges and maximal for an equal 50%-50% mixture, is
the microscopic mechanism leading to the nearly perfect fluidity.


title:
Toeplitz and Hankel determinants with singularities: announcement of
  results

abstract:
  We obtain asymptotics for Toeplitz, Hankel, and Toeplitz+Hankel determinants
whose symbols possess Fisher-Hartwig singularities. Details of the proofs will
be presented in another publication.


title: Electricity Demand and Energy Consumption Management System

abstract:
  This project describes the electricity demand and energy consumption
management system and its application to Southern Peru smelter. It is composed
of an hourly demand-forecasting module and of a simulation component for a
plant electrical system. The first module was done using dynamic neural
networks with backpropagation training algorithm; it is used to predict the
electric power demanded every hour, with an error percentage below of 1%. This
information allows efficient management of energy peak demands before this
happen, distributing the raise of electric load to other hours or improving
those equipments that increase the demand. The simulation module is based in
advanced estimation techniques, such as: parametric estimation, neural network
modeling, statistic regression and previously developed models, which simulates
the electric behavior of the smelter plant. These modules facilitate
electricity demand and consumption proper planning, because they allow knowing
the behavior of the hourly demand and the consumption patterns of the plant,
including the bill components, but also energy deficiencies and opportunities
for improvement, based on analysis of information about equipments, processes
and production plans, as well as maintenance programs. Finally the results of
its application in Southern Peru smelter are presented.


title: Exact solution for the simplest binary system of Kerr black holes

abstract:
  The full metric describing two counter-rotating identical Kerr black holes
separated by a massless strut is derived in the explicit analytical form. It
contains three arbitrary parameters which are the Komar mass M, Komar angular
momentum per unit mass a of one of the black holes (the other has the same mass
and equal but opposite angular momentum) and the coordinate distance R between
the centers of the horizons. In the limit of extreme black holes, the metric
becomes a special member of the Kinnersly-Chitre five-parameter family of
vacuum solutions generalizing the Tomimatsu-Sato delta=2 spacetime, and we
present the complete set of metrical fields defining this limit.


title:
The fully connected N-dimensional skeleton: probing the evolution of the
  cosmic web

abstract:
  A method to compute the full hierarchy of the critical subsets of a density
field is presented. It is based on a watershed technique and uses a probability
propagation scheme to improve the quality of the segmentation by circumventing
the discreteness of the sampling. It can be applied within spaces of arbitrary
dimensions and geometry. This recursive segmentation of space yields, for a
$d$-dimensional space, a $d-1$ succession of $n$-dimensional subspaces that
fully characterize the topology of the density field. The final 1D manifold of
the hierarchy is the fully connected network of the primary critical lines of
the field : the skeleton. It corresponds to the subset of lines linking maxima
to saddle points, and provides a definition of the filaments that compose the
cosmic web as a precise physical object, which makes it possible to compute any
of its properties such as its length, curvature, connectivity etc... When the
skeleton extraction is applied to initial conditions of cosmological N-body
simulations and their present day non linear counterparts, it is shown that the
time evolution of the cosmic web, as traced by the skeleton, is well accounted
for by the Zel'dovich approximation. Comparing this skeleton to the initial
skeleton undergoing the Zel'dovich mapping shows that two effects are competing
during the formation of the cosmic web: a general dilation of the larger
filaments that is captured by a simple deformation of the skeleton of the
initial conditions on the one hand, and the shrinking, fusion and disappearance
of the more numerous smaller filaments on the other hand. Other applications of
the N dimensional skeleton and its peak patch hierarchy are discussed.


title:
Universal Rise of Hadronic Total Cross Sections based on Forward pi p
  and pbarp(pp) Scatterings

abstract:
  Recently there are several evidences of the increase of the total cross
section sigma(tot) to be log2 s consistent with the Froissart unitarity bound,
and the COMPETE collaborations in the PDG have further assumed sigma(tot) = B
log2(s/s0) to extend its universal rise with a common value of B for all the
hadronic scatterings. However, there is no rigorous proof yet based only on
QCD. Therefore, it is worthwhile to prove this universal rise of sigma(tot)
even empirically. In this letter we attempt to obtain the value of B for pi p
scattering, B(pi p), with reasonable accuracy by taking into account the rich
pi p data in all the energy regions. We use the finite-energy sum rule(FESR)
expressed in terms of the pi p scattering data in the low and intermediate
energies as a constraint between high-energy parameters. We then have searched
for the simultaneous best fit to the sigma(tot) and rho ratios, the ratios of
the real to imaginary parts of the forward scattering amplitudes. The lower
energy data are included in the integral of FESR, the more precisely determined
is the non-leading term such as log s, and then helps to determine the leading
terms like log2 s. We have derived the value of B(pi p) as B(pi p)=0.311 +-
0.044mb. This value is to be compared with the value of B for pbarp,pp
scattering, B(pp), in our previous analysis[11], B(pp)=0.289 +- 0.023mb. Thus,
our result appears to support the universality hypothesis.


title: Chern classes of blow-ups

abstract:
  We extend the classical formula of Porteous for blowing-up Chern classes to
the case of blow-ups of possibly singular varieties along regularly embedded
centers. The proof of this generalization is perhaps conceptually simpler than
the standard argument for the nonsingular case, involving Riemann-Roch without
denominators. The new approach relies on the explicit computation of an ideal,
and a mild generalization of the well-known formula for the normal bundle of a
proper transform.
  We also discuss alternative, very short proofs of the standard formula in
some cases: an approach relying on the theory of Chern-Schwartz-MacPherson
classes (working in characteristic 0), and an argument reducing the formula to
a straightforward computation of Chern classes for sheaves of differential
1-forms with logarithmic poles (when the center of the blow-up is a complete
intersection).


title: Soft supersymmetry breaking from stochastic superspace

abstract:
  We propose a new realization of softly broken supersymmetric theories as
theories defined on stochastic superspace. At the classical level, the
supersymmetry breaking is parameterized in terms of a single (in general
complex) mass parameter, $\xi$, describing the stochasticity of the
Grassmannian superspace coordinates. In the context of the standard model with
stochastic supersymmetry, the structure of the soft breaking terms has various
characteristic features that can be tested in LHC experiments. Namely, at the
classical level, the $B_{\mu}$ parameter, the universal soft trilinear coupling
$A_0$, the universal gaugino mass $m_{1/2}$ and the universal scalar mass $m_0$
are given solely in terms of $\xi$; there are no other arbitrary parameters.
The relations are $B_\mu = \xi^*$, $A_0 = 2\xi^*$, $m_{1/2} = |\xi|/2$ and $m_0
= 0$. At the quantum level, these relations hold at a certain scale $\Lambda$
which is a second free parameter. The soft scalar masses, zero at tree-level,
are induced radiatively through the renormalization group equations at
one-loop. With this pattern of soft breaking terms, large supersymmetric
contributions to FCNC processes are avoided. As a concrete illustration of the
proposed formalism, we consider a minimal model, which is just the constrained
MSSM with the stochastic superspace relations amongst the soft-breaking
parameters imposed at the scale $\Lambda$. We show that this theory is
phenomenologically viable for a certain region in the $(\xi,\Lambda)$ parameter
space. Some sensible extensions of the minimal model are then briefly
discussed.


title: On Coxeter Diagrams of complex reflection groups

abstract:
  We study Coxeter diagrams of some unitary reflection groups. Using solely the
combinatorics of diagrams, we give a new proof of the classification of root
lattices defined over $\cE = \ZZ[e^{2 \pi i/3}]$: there are only four such
lattices, namely, the $\cE$-lattices whose real forms are $A_2$, $D_4$, $E_6$
and $E_8$. Next, we address the issue of characterizing the diagrams for
unitary reflection groups, a question that was raised by Brou\'{e}, Malle and
Rouquier. To this end, we describe an algorithm which, given a unitary
reflection group $G$, picks out a set of complex reflections. The algorithm is
based on an analogy with Weyl groups. If $G$ is a Weyl group, the algorithm
immediately yields a set of simple roots. Experimentally we observe that if $G$
is primitive and $G$ has a set of roots whose $\ZZ$--span is a discrete subset
of the ambient vector space, then the algorithm selects a minimal generating
set for $G$. The group $G$ has a presentation on these generators such that if
we forget that the generators have finite order then we get a (Coxeter-like)
presentation of the corresponding braid group. For some groups, such as
$G_{33}$ and $G_{34}$, new diagrams are obtained. For $G_{34}$, our new diagram
extends to an "affine diagram" with $\ZZ/7\ZZ$ symmetry.


title:
Detection and extraction of signals from the epoch of reionization using
  higher order one-point statistics

abstract:
  Detecting redshifted 21cm emission from neutral hydrogen in the early
Universe promises to give direct constraints on the epoch of reionization
(EoR). It will, though, be very challenging to extract the cosmological signal
(CS) from foregrounds and noise which are orders of magnitude larger.
Fortunately, the signal has some characteristics which differentiate it from
the foregrounds and noise, and we suggest that using the correct statistics may
tease out signatures of reionization. We generate mock datacubes simulating the
output of the Low Frequency Array (LOFAR) EoR experiment. These cubes combine
realistic models for Galactic and extragalactic foregrounds and the noise with
three different simulations of the CS. We fit out the foregrounds, which are
smooth in the frequency direction, to produce residual images in each frequency
band. We denoise these images and study the skewness of the one-point
distribution in the images as a function of frequency. We find that, under
sufficiently optimistic assumptions, we can recover the main features of the
redshift evolution of the skewness in the 21cm signal. We argue that some of
these features - such as a dip at the onset of reionization, followed by a rise
towards its later stages - may be generic, and give us a promising route to a
statistical detection of reionization.


title:
Design of double-negative metamaterials using single-layer plasmonic
  structures

abstract:
  We propose a design for optical-frequency double-negative metamaterials
(DMNs) in which the unit cell is formed by a single-layer plasmonic inclusion.
By introducing some properly arranged stepwise modulations onto the inclusions,
the effective permittivity and permeability of the material may become
simultaneously negative due to the excitation of higher-order multipole
plamonic (electrostatic) resonances. The approach opens a possibility to
construct low-loss optical DNMs with great engineering simplicity.


title: Ergodic Properties of Fractional Brownian-Langevin Motion

abstract:
  We investigate the time average mean square displacement
$\overline{\delta^2}(x(t))=\int_0^{t-\Delta}[x(t^\prime+\Delta)-x(t^\prime)]^2
dt^\prime/(t-\Delta)$ for fractional Brownian and Langevin motion. Unlike the
previously investigated continuous time random walk model $\overline{\delta^2}$
converges to the ensemble average $<x^2 > \sim t^{2 H}$ in the long measurement
time limit. The convergence to ergodic behavior is however slow, and
surprisingly the Hurst exponent $H=3/4$ marks the critical point of the speed
of convergence. When $H<3/4$, the ergodicity breaking parameter ${EB} = {Var}
(\overline{\delta^2}) / < \overline{\delta^2} >^2\sim k(H) \cdot\Delta\cdot
t^{-1}$, when $H=3/4$, ${EB} \sim (9/16)(\ln t) \cdot\Delta \cdot t^{-1}$, and
when $3/4<H <1, {EB} \sim k(H)\Delta^{4-4H} t^{4H-4}$. In the ballistic limit
$H \to 1$ ergodicity is broken and ${EB} \sim 2$. The critical point $H=3/4$ is
marked by the divergence of the coefficient $k(H)$. Fractional Brownian motion
as a model for recent experiments of sub-diffusion of mRNA in the cell is
briefly discussed and comparison with the continuous time random walk model is
made.


title:
Hyperfine induced $1s2s ^1S_0 \to 1s^2 ^1S_0$ M1 transition of He-like
  ions

abstract:
  Hyperfine induced $1s2s ^1S_0 \to 1s^2 ^1S_0$ M1 transition probabilities of
He-like ions have been calculated from relativistic configuration interaction
wavefunctions including the frequency independent Breit interaction and QED
effects. Present results for {$^{151}$}Eu and {$^{155}$}Gd are in good
agreement with previous calculations [Phys. Rev. A {\bf 63}, 054105 (2001)].
Electronic data are given in terms of a general scaling law in $Z$ that, given
isotopic nuclear spin and magnetic moment, allows hyperfine induced decay rates
to be estimated for any isotope. The results should be helpful for future
experimental investigations on QED and parity non-conservation effects.


title:
Inverse Compton gamma-ray models for remnants of Galactic type Ia
  supernovae?

abstract:
  We theoretically and phenomenologically investigate the question whether the
gamma-ray emission from the remnants of the type Ia supernovae SN 1006, Tycho's
SN and Kepler's SN can be the result of electron acceleration alone. The
observed synchrotron spectra of the three remnants are used to determine the
average momentum distribution of nonthermal electrons as a function of the
assumed magnetic field strength. Then the inverse Compton emission spectrum in
the Cosmic Microwave Background photon field is calculated and compared with
the existing upper limits for the very high energy gamma-ray flux from these
sources. It is shown that the expected interstellar magnetic fields
substantially overpredict even these gamma-ray upper limits. Only rather
strongly amplified magnetic fields could be compatible with such low gamma-ray
fluxes. However this would require a strong component of accelerated nuclear
particles whose energy density substantially exceeds that of the synchrotron
electrons, compatible with existing theoretical acceleration models for nuclear
particles and electrons. Even though the quantitative arguments are simplistic,
they appear to eliminate simplistic phenomenological claims in favor of a
inverse Compton gamma-ray scenario for these sources.


title: Hopfing and Puffing Warped Anti-de Sitter Space

abstract:
  Three dimensional spacelike warped anti-de Sitter space is studied in the
context of Einstein theories of gravity and string theory, where there is no
gravitational Chern-Simons term in the action. We propose that it is
holographically dual to a two-dimensional conformal field theory with equal
left and right moving central charges. Various checks of the central charges
are offered, based on the Bekenstein-Hawking entropy of the stretched warped
black holes and warped self-dual solutions. The proposed central charges are
applied to compute the Bekenstein-Hawking entropy of the Hopf T-dual of
six-dimensional dyonic black strings which have a near horizon consisting of
three dimensional warped anti-de Sitter space times a three-sphere. We find
that the Hopf T-duality is a map between thermal states with equal entropy of
the CFTs dual to the dyonic black string and the Hopf T-dualized black string.


title:
Calculation of the total gamma-spectra of the fast neutrons capture in
  the isotopes 117,119Sn for the different parameters of cascade gamma-decay

abstract:
  The gamma-spectra were calculated for the set of different level densities
and radiative strength functions. The sufficiently precise reproduction of the
experiment is impossible without taking into account the influence of the
process of the nucleons Cooper pairs breaking on any nuclei cascade gamma-decay
parameters.


title:
Direct measurement of the cross-shock electric potential at low plasma
  $\beta$, quasi-perpendicular bow shocks

abstract:
  We use the Cluster EFW experiment to measure the cross-shock electric field
at ten low $\beta$, quasi-perpendicular supercritical bow shock crossings on
March 31, 2001. The electric field data are Lorentz-tranformed to a Normal
Incidence frame (NIF), in which the incoming solar wind velocity is aligned
with the shock normal. In a boundary normal coordinate system, the cross-shock
(normal) electric field is integrated to obtain the cross shock potential.
Using this technique, we measure the cross-shock potential at each of the four
Cluster satellites and using an electric field profile averaged between the
four satellites. Typical values are in the range 500-2500 volts. The
cross-shock potential measurements are compared with the ion kinetic energy
change across the shock. The cross-shock potential is measured to be from 23 to
236% of the ion energy change, with large variations between the four Cluster
spacecraft at the same shock. These results indicate that solar wind flow
through the shock is likely to be variable in time and space and resulting
structure of the shock is therefore nonstationary.


title: Szasz Analytic Functions and Noncompact K\"{a}hler Toric Manifolds

abstract:
  We show that the classical Szasz analytic function $S_N(f)(x)$ is obtained by
applying the pseudo-differential operator $f(N^{-1}D_{\theta})$ to the Bergman
kernels for the Bargmann-Fock space. The expression generalizes immediately to
any smooth polarized noncompact complete toric \kahler manifold, defining the
generalized Szasz analytic function $S_{h^N}(f)(x)$. About $S_{h^N}(f)(x)$, we
prove that it admits complete asymptotics and there exists a universal scaling
limit. % We also consider some dilation operator composed with $S_{h^N}(f)(x)$
and we give an estimate about this composition. As an example, we will further
compute $S_{h^N}(f)(x)$ for the Bergman metric on the unit ball.


title:
Problems of experimental determination of parameters of nucleus and
  applicability of the Bohr-Mottelson hypothesis

abstract:
  Population of a number of excited levels of 51V and 57Fe has been determined
from the data of the ENDSF file up to the excitation energy of about 7 and 5.2
MeV, respectively. It cannot be reproduced in the region of their maximal
energies in the framework of assumption on the independence of partial
radiative widths on the structure of decaying level and excited one, at least,
lower than 0.5Bn. Therefore, it is impossible to estimate the actual degree of
reliability of data on the level density and radiative widths of cascade
gamma-transitions in light spherical nuclei obtained from the spectrum analysis
of nuclear reactions, which do not take into account this circumstance.


title: Profile and polarization characteristics of energetic pulsars

abstract:
  In this paper we compare the characteristics of pulsars with a high spin-down
energy loss rate (Edot) against those with a low Edot. We show that the
differences in the total intensity pulse morphology between the two classes are
in general rather subtle. A much more significant difference is the fractional
polarization which is very high for high Edot pulsars and low for low Edot
pulsars. The Edot at the transition is very similar to the death line predicted
for curvature radiation. This suggests a possible link between high energy and
radio emission in pulsars and could imply that gamma-ray efficiency is
correlated with the degree of linear polarization in the radio band. The degree
of circular polarization is in general higher in the second component of
doubles, which is possibly caused by the effect of co-rotation on the curvature
of the field lines in the inertial observer frame.
  The most direct link between the high energy emission and the radio emission
could be the sub-group of pulsars which we call the energetic wide beam
pulsars. These young pulsars have very wide profiles with steep edges and are
likely to be emitted from a single magnetic pole. The similarities with the
high energy profiles suggest that both types of emission are produced at the
same extended height range in the magnetosphere. Alternatively, the beams of
the energetic wide beam pulsars could be magnified by propagation effects in
the magnetosphere. This would naturally lead to decoupling of the wave modes,
which could explain the high degree of linear polarization. As part of this
study, we have discovered three previous unknown interpulse pulsars (and we
detected one for the first time at 20 cm). We also obtained rotation measures
for 18 pulsars whose values had not previously been measured.


title: Wreath Product Symmetric Functions

abstract:
  We systematically study wreath product Schur functions and give a
combinatorial construction using colored partitions and tableaux. The Pieri
rule and the Littlewood-Richardson rule are studied. We also discuss the
connection with representations of generalized symmetric groups.


title: Inflation in the nonminimal theory with `K(phi)R' term

abstract:
  A class of inflationary models with the nonminimal coupling term `K(phi)R' is
considered. We show that the successful inflation can take place if the ratio
between the square of the nonminimal coupling term and the potential for the
scalar goes asymptotically constant.


title:
Constraining the Spin-Independent WIMP-Nucleon Coupling from Direct Dark
  Matter Detection Data

abstract:
  Weakly Interacting Massive Particles (WIMPs) are one of the leading
candidates for Dark Matter. For understanding the properties of WIMPs and
identifying them among new particles produced at colliders (hopefully in the
near future), determinations of their mass and their couplings on nucleons from
direct Dark Matter detection experiments are essential. Based on our method for
determining the WIMP mass model-independently from experimental data, we
present a way to also estimate the spin-independent (SI) WIMP-nucleon coupling
by using measured recoil energies directly. This method isindependent of the as
yet unknown velocity distribution of halo WIMPs. In spite of the uncertainty of
the local WIMP density (of a factor of ~ 2), at least an upper limit on the SI
WIMP-nucleon coupling could be given, once two (or more) experiments with
different target nuclei obtain positive signals. In a background-free
environment, for a WIMP mass of 100 GeV its SI coupling on nucleons could in
principle be estimated with a statistical error of only ~ 15% with just 50
events from each experiment.


title:
Event-horizon-scale structure in the supermassive black hole candidate
  at the Galactic Centre

abstract:
  The cores of most galaxies are thought to harbour supermassive black holes,
which power galactic nuclei by converting the gravitational energy of accreting
matter into radiation (ref 1). Sagittarius A*, the compact source of radio,
infrared and X-ray emission at the centre of the Milky Way, is the closest
example of this phenomenon, with an estimated black hole mass that is 4 million
times that of the Sun (refs. 2,3). A long-standing astronomical goal is to
resolve structures in the innermost accretion flow surrounding Sgr A* where
strong gravitational fields will distort the appearance of radiation emitted
near the black hole. Radio observations at wavelengths of 3.5 mm and 7 mm have
detected intrinsic structure in Sgr A*, but the spatial resolution of
observations at these wavelengths is limited by interstellar scattering (refs.
4-7). Here we report observations at a wavelength of 1.3 mm that set a size of
37 (+16, -10; 3-sigma) microarcseconds on the intrinsic diameter of Sgr A*.
This is less than the expected apparent size of the event horizon of the
presumed black hole, suggesting that the bulk of SgrA* emission may not be not
centred on the black hole, but arises in the surrounding accretion flow.


title:
NP-Completeness of Hamiltonian Cycle Problem on Rooted Directed Path
  Graphs

abstract:
  The Hamiltonian cycle problem is to decide whether a given graph has a
Hamiltonian cycle. Bertossi and Bonuccelli (1986, Information Processing
Letters, 23, 195-200) proved that the Hamiltonian Cycle Problem is NP-Complete
even for undirected path graphs and left the Hamiltonian cycle problem open for
directed path graphs. Narasimhan (1989, Information Processing Letters, 32,
167-170) proved that the Hamiltonian Cycle Problem is NP-Complete even for
directed path graphs and left the Hamiltonian cycle problem open for rooted
directed path graphs. In this paper we resolve this open problem by proving
that the Hamiltonian Cycle Problem is also NP-Complete for rooted directed path
graphs.


title: Research News--Recent Advances in the Study of B-meson systems

abstract:
  An accessible review of recent discoveries concerning B-meson systems
including those from Belle and BaBar on direct CP asymmetries, and the
measurement of the width difference of B_s-meson system at Fermilab is
presented.

categories: physics.pop-ph hep-ex hep-ph physics.ed-ph


title: Finding conjugate stabilizer subgroups in PSL(2; q) and related groups

abstract:
  We reduce a case of the hidden subgroup problem (HSP) in SL(2; q), PSL(2; q),
and PGL(2; q), three related families of finite groups of Lie type, to
efficiently solvable HSPs in the affine group AGL(1; q). These groups act on
projective space in an almost 3-transitive way, and we use this fact in each
group to distinguish conjugates of its Borel (upper triangular) subgroup, which
is also the stabilizer subgroup of an element of projective space. Our
observation is mainly group-theoretic, and as such breaks little new ground in
quantum algorithms. Nonetheless, these appear to be the first positive results
on the HSP in finite simple groups such as PSL(2; q).


title:
High-Rate Space-Time Coded Large MIMO Systems: Low-Complexity Detection
  and Channel Estimation

abstract:
  In this paper, we present a low-complexity algorithm for detection in
high-rate, non-orthogonal space-time block coded (STBC) large-MIMO systems that
achieve high spectral efficiencies of the order of tens of bps/Hz. We also
present a training-based iterative detection/channel estimation scheme for such
large STBC MIMO systems. Our simulation results show that excellent bit error
rate and nearness-to-capacity performance are achieved by the proposed
multistage likelihood ascent search (M-LAS) detector in conjunction with the
proposed iterative detection/channel estimation scheme at low complexities. The
fact that we could show such good results for large STBCs like 16x16 and 32x32
STBCs from Cyclic Division Algebras (CDA) operating at spectral efficiencies in
excess of 20 bps/Hz (even after accounting for the overheads meant for pilot
based training for channel estimation and turbo coding) establishes the
effectiveness of the proposed detector and channel estimator. We decode perfect
codes of large dimensions using the proposed detector. With the feasibility of
such a low-complexity detection/channel estimation scheme, large-MIMO systems
with tens of antennas operating at several tens of bps/Hz spectral efficiencies
can become practical, enabling interesting high data rate wireless
applications.


title:
First Measurement of $\nu_\mu$ and $\nu_e$ Events in an Off-Axis
  Horn-Focused Neutrino Beam

abstract:
  We report the first observation of off-axis neutrino interactions in the
MiniBooNE detector from the NuMI beamline at Fermilab. The MiniBooNE detector
is located 745 m from the NuMI production target, at 110 mrad angle
($6.3^{\circ}$) with respect to the NuMI beam axis. Samples of charged current
quasi-elastic $\nu_{\mu}$ and $\nu_e$ interactions are analyzed and found to be
in agreement with expectation. This provides a direct verification of the
expected pion and kaon contributions to the neutrino flux and validates the
modeling of the NuMI off-axis beam.


title:
Hard X-Ray Spectrum from West Lobe of Radio Galaxy Fornax A Observed
  with Suzaku

abstract:
  An observation of the West lobe of radio galaxy Fornax A (NGC 1316) with
Suzaku is reported. Since Feigelson et al. (1995) and Kaneda et al. (1995)
discovered the cosmic microwave background boosted inverse-Comptonized (IC)
X-rays from the radio lobe, the magnetic field and electron energy density in
the lobes have been estimated under the assumption that a single component of
the relativistic electrons generates both the IC X-rays and the synchrotron
radio emission. However, electrons generating the observed IC X-rays in the 1
-- 10 keV band do not possess sufficient energy to radiate the observed
synchrotron radio emission under the estimated magnetic field of a few micro-G.
On the basis of observations made with Suzaku, we show in the present paper
that a 0.7 -- 20 keV spectrum is well described by a single power-law model
with an energy index of 0.68 and a flux density of 0.12+/-0.01 micro-Jy at 1
keV from the West lobe. The derived multiwavelength spectrum strongly suggests
that a single electron energy distribution over a Lorentz factor gamma = 300 -
90000 is responsible for generating both the X-ray and radio emissions. The
derived physical quantities are not only consistent with those reported for the
West lobe, but are also in very good agreement with those reported for the East
lobe.


title:
Phenomenological Meaning of a Neutrino Mass Matrix Related to Up-Quark
  Masses

abstract:
  Recently, a curious neutrino mass matrix has been proposed: it is related to
up-quark masses, and it can excellently give a nearly tribimaxial mixing. It is
pointed out that, in order to obtain such successful results, three
phenomenological relations among masses and CKM parameters must be
simultaneously satisfied. This suggests that there must be a specific
flavor-basis in which down-quark and charged lepton mass matrices are
simultaneously diagonalized.


title: Kinetics of a mixed spin-1/2 and spin-3/2 Ising ferrimagnetic model

abstract:
  We present a study, within a mean-field approach, of the kinetics of a mixed
ferrimagnetic model on a square lattice in which two interpenetrating square
sublattices have spins that can take two values, $\sigma=\pm1/2$, alternated
with spins that can take the four values, $S=\pm3/2, \pm1/2$. We use the
Glauber-type stochastic dynamics to describe the time evolution of the system
with a crystal-field interaction in the presence of a time-dependent
oscillating external magnetic field. The nature (continuous and discontinuous)
of transition is characterized by studying the thermal behaviors of average
order parameters in a period. The dynamic phase transition points are obtained
and the phase diagrams are presented in the reduced magnetic field amplitude
$(h)$ and reduced temperature $(T)$ plane, and in the reduced temperature and
interaction parameter planes, namely in the $(h, T)$ and $(d, T)$ planes, $d$
is the reduced crystal-field interaction. The phase diagrams always exhibit a
tricritical point in $(h, T)$ plane, but do not exhibit in the $(d, T)$ plane
for low values of $h$. The dynamic multicritical point or dynamic critical end
point exist in the $(d, T)$ plane for low values of $h$. Moreover, phase
diagrams contain paramagnetic $(p)$, ferromagnetic $(f)$, ferrimagnetic $(i)$
phases, two coexistence or mixed phase regions, $(f+p)$ and $(i+p)$, that
strongly depend on interaction parameters.


title:
Signatures of non-universal gaugino and scalar masses at the Large
  Hadron Collider

abstract:
  We perform a multichannel analysis in context of the Large Hadron Collider
(LHC) for supersymmetric (SUSY) theories with high-scale non-universal gaugino
masses arising from different non-singlet representations of SU(5) and SO(10)
gauge groups in a SUSY-GUT scenario and non-universal scalar masses in form of
squark-slepton non-universality, third family scalar non-universality and that
arising due to SO(10) $D$-terms. We present the numerical predictions over a
wide region of parameter space using event generator {\tt Pythia}. Certain
broad features emerge from the study which may be useful to identify these
non-universal schemes and distinguish them from the minimal supergravity
(mSUGRA) framework.


title: Hidden Symmetries of Higher-Dimensional Rotating Black Holes

abstract:
  In this thesis we study higher-dimensional rotating black holes. Such black
holes are widely discussed in string theory and brane-world models at present.
We demonstrate that even the most general known Kerr-NUT-(A)dS spacetime,
describing the general rotating higher-dimensional asymptotically (anti) de
Sitter black hole with NUT parameters, is in many aspects similar to its
four-dimensional counterpart. Namely, we show that it admits a fundamental
hidden symmetry associated with the principal conformal Killing-Yano tensor.
Such a tensor generates towers of hidden and explicit symmetries. The tower of
Killing tensors is responsible for the existence of irreducible, quadratic in
momenta, conserved integrals of geodesic motion. These integrals, together with
the integrals corresponding to the tower of explicit symmetries, make geodesic
equations in the Kerr-NUT-(A)dS spacetime completely integrable. We further
demonstrate that in this spacetime the Hamilton-Jacobi, Klein-Gordon, and
stationary string equations allow complete separation of variables and the
problem of finding parallel-propagated frames reduces to the set of the first
order ordinary differential equations. Moreover, we show that the
Kerr-NUT-(A)dS spacetime is the most general Einstein space which possesses all
these properties. We also explicitly derive the most general (off-shell)
canonical metric admitting the principal conformal Killing-Yano tensor and
demonstrate that such a metric is necessarily of the special algebraic type D
of the higher-dimensional algebraic classification. The results presented in
this thesis describe the new and complete picture of the relationship of hidden
symmetries and rotating black holes in higher dimensions.


title: Dynamical renormalization group methods in theory of eternal inflation

abstract:
  Dynamics of eternal inflation on the landscape admits description in terms of
the Martin-Siggia-Rose (MSR) effective field theory that is in one-to-one
correspondence with vacuum dynamics equations. On those sectors of the
landscape, where transport properties of the probability measure for eternal
inflation are important, renormalization group fixed points of the MSR
effective action determine late time behavior of the probability measure. I
argue that these RG fixed points may be relevant for the solution of the gauge
invariance problem for eternal inflation.


title:
A priori convergence estimates for a rough Poisson-Dirichlet problem
  with natural vertical boundary conditions

abstract:
  Stents are medical devices designed to modify blood flow in aneurysm sacs, in
order to prevent their rupture. Some of them can be considered as a locally
periodic rough boundary. In order to approximate blood flow in arteries and
vessels of the cardio-vascular system containing stents, we use multi-scale
techniques to construct boundary layers and wall laws. Simplifying the flow we
turn to consider a 2-dimensional Poisson problem that conserves essential
features related to the rough boundary. Then, we investigate convergence of
boundary layer approximations and the corresponding wall laws in the case of
Neumann type boundary conditions at the inlet and outlet parts of the domain.
The difficulty comes from the fact that correctors, for the boundary layers
near the rough surface, may introduce error terms on the other portions of the
boundary. In order to correct these spurious oscillations, we introduce a
vertical boundary layer. Trough a careful study of its behavior, we prove
rigorously decay estimates. We then construct complete boundary layers that
respect the macroscopic boundary conditions. We also derive error estimates in
terms of the roughness size epsilon either for the full boundary layer
approximation and for the corresponding averaged wall law.


title: Fractional diffusion limit for collisional kinetic equations

abstract:
  This paper is devoted to diffusion limits of linear Boltzmann equations. When
the equilibrium distribution function is Maxwellian distribution, it is well
known that for an appropriate time scale, the small mean free path limit gives
rise to a diffusion equation. In this paper, we consider situations in which
the equilibrium distribution function is a heavy-tailed distribution with
infinite variance. We then show that for an appropriate time scale, the small
mean free path limit gives rise to a fractional diffusion equation.


title: Temperature dependence of the electron spin g factor in GaAs

abstract:
  The temperature dependence of the electron spin $g$ factor in GaAs is
investigated experimentally and theoretically. Experimentally, the $g$ factor
was measured using time-resolved Faraday rotation due to Larmor precession of
electron spins in the temperature range between 4.5 K and 190 K. The experiment
shows an almost linear increase of the $g$ value with the temperature. This
result is in good agreement with other measurements based on photoluminescence
quantum beats and time-resolved Kerr rotation up to room temperature. The
experimental data are described theoretically taking into account a diminishing
fundamental energy gap in GaAs due to lattice thermal dilatation and
nonparabolicity of the conduction band calculated using a five-level kp model.
At higher temperatures electrons populate higher Landau levels and the average
$g$ factor is obtained from a summation over many levels. A very good
description of the experimental data is obtained indicating that the observed
increase of the spin $g$ factor with the temperature is predominantly due to
band's nonparabolicity.


title:
Modeling quantum scattering of fundamental particles by classical,
  deterministic processes

abstract:
  We point out that results obtained by M. Ribaric and L. Sustersic,
hep-th/0403084, and by M. Blasone, P. Jizba and H. Kleinert, quant-ph/0409021,
suggest that the path-integral formalism is the key to a derivation of quantum
physics from classical, deterministic physics in the four-dimensional
space-time. These results and the 't Hooft conjecture, hep-th/0104219, suggest
to consider a relativistic, non-material medium, an ether, as a base for
non-local hidden-variable models of the physical universe.


title:
Annihilative fractals of coffee on milk formed by Rayleigh-Taylor
  instability

abstract:
  We have discovered a new fractal pattern, coffee exhibits on a horizontal
surface, with a fractal dimension $1.88 \pm 0.06$, when a heavy coffee droplet
interacts with the surface of lighter milk. Parts of coffee pattern on the
surface disappear due to Rayleigh-Taylor instability, and the annihilative
behavior produces the fractal pattern. Coffee fractals and the Sierpinski
carpet have common features, such as the fractal dimension, annihilative
behavior, and an exponential decrease of the pattern area. It is suggested the
formation of fractal follows a rule similar to that of the Sierpinski carpet.


title:
Hydroxylated MgO (111) reconstructions: why the case for clean surfaces
  does not hold water

abstract:
  We report an experimental and theoretical analysis of the root(3)xroot(3)-R30
and 2x2 reconstructions on the MgO (111) surface combining transmission
electron microscopy, x-ray photoelectron spectroscopy, and reasonably accurate
density functional calculations using the meta-GGA functional TPSS. The
experimental data clearly shows that the surfaces contain significant coverages
of hydroxyl terminations, even after UHV annealing, and as such cannot be the
structures which have been previously reported. For the 2x2 surfaces a
relatively simple structural framework is detailed which fits all the
experimental and theoretical data. For the root(3)xroot(3) there turn out to be
two plausible structures and neither the experimental nor theoretical results
can differentiate between the two within error. However, by examining the
conditions under which the surface is formed we describe a kinetic route for
the transformation between the different reconstructions that involves mobile
hydroxyl groups and protons, and relatively immobile cations, which strongly
suggests only one of the two root(3)xroot(3) structures.


title: Gamma flashes from relativistic electron-positron plasma droplets

abstract:
  Ultra-intense lasers are expected to produce, in near future, relativistic
electron-positron plasma droplets. Considering the local photon production rate
in complete leading order in quantum electrodynamics (QED), we point out that
these droplets are interesting sources of gamma ray flashes


title: Correlations and Omori law in Spamming

abstract:
  The most costly and annoying characteristic of the e-mail communication
system is the large number of unsolicited commercial e-mails, known as spams,
that are continuously received. Via the investigation of the statistical
properties of the spam delivering intertimes, we show that spams delivered to a
given recipient are time correlated: if the intertime between two consecutive
spams is small (large), then the next spam will most probably arrive after a
small (large) intertime. Spam temporal correlations are reproduced by a
numerical model based on the random superposition of spam sequences, each one
described by the Omori law. This and other experimental findings suggest that
statistical approaches may be used to infer how spammers operate.


title: Physical States and BRST Operators for Higher-spin $W$ Strings

abstract:
  In this paper, we mainly investigate the $W_{2,s}^{M}\otimes W_{2,s}^{L}$
system, in which the matter and the Liouville subsystems generate $W_{2,s}^{M}$
and $W_{2,s}^L$ algebras respectively. We first give a brief discussion of the
physical states for corresponding $W$ stings. The lower states are given by
freezing the spin-2 and spin-$s$ currents. Then, introducing two pairs of
ghost-like fields, we give the realizations of $W_{1,2,s}$ algebras. Based on
these linear realizations, BRST operators for $W_{2,s}$ algebras are obtained.
Finally, we construct new BRST charges of Liouville system for $W_{2,s}^{L}$
strings at the specific values of central charges $c$: $c=-{22/5}$ for
$W_{2,3}^{L}$ algebra, $c=-24$ for $W_{2,4}^{L}$ algebra and $c=-2,-{286/3}$
for $W_{2,6}^{L}$ algebra, at which the corresponding $W_{2,s}^L$ algebras are
singular.


title:
High-frequency VLBI observations of SgrA* during a multi-frequency
  campaign in May 2007

abstract:
  In May 2007 the compact radio source Sgr A* was observed in a global
multi-frequency monitoring campaign, from radio to X-ray bands. Here we present
and discuss first and preliminary results from polarization sensitive VLBA
observations, which took place during May 14-25, 2007. Here, Sgr A* was
observed in dual polarization on 10 consecutive days at 22, 43, and 86 GHz. We
describe the VLBI experiments, our data analysis, monitoring program and show
preliminary images obtained at the various frequencies. We discuss the data
with special regard also to the short term variability.


title: The Correlation between X-ray and UV Properties of BAL QSOs

abstract:
  We compile a large sample of broad absorption lines (BAL) quasars with X-ray
observations from the \xmm archive data and Sloan Digital Sky Survey Data
Release 5. The sample consists of 41 BAL QSOs. Among 26 BAL quasars detected in
X-ray, spectral analysis is possible for twelve objects. X-ray absorption is
detected in all of them. Complementary to that of \citet{gall06} (thereafter
G06), our sample spans wide ranges of both BALnicity Index (BI) and maximum
outflow velocity (\vmax). Combining our sample with G06's, we find very
significant correlations between the intrinsic X-ray weakness with both
BALnicity Index (BI) and the maximum velocity of absorption trough. We do not
confirm the previous claimed correlation between absorption column density and
broad absorption line parameters. We tentatively interpret this as that X-ray
absorption is necessary to the production of the BAL outflow, but the
properties of the outflow are largely determined by intrinsic SED of the
quasars.


title: The Hubble Legacy Archive NICMOS Grism Data

abstract:
  The Hubble Legacy Archive (HLA) aims to create calibrated science data from
the Hubble Space Telescope archive and make them accessible via user-friendly
and Virtual Observatory (VO) compatible interfaces. It is a collaboration
between the Space Telescope Science Institute (STScI), the Canadian Astronomy
Data Centre (CADC) and the Space Telescope - European Coordinating Facility
(ST-ECF). Data produced by the Hubble Space Telescope (HST) instruments with
slitless spectroscopy modes are among the most difficult to extract and
exploit. As part of the HLA project, the ST-ECF aims to provide calibrated
spectra for objects observed with these HST slitless modes. In this paper, we
present the HLA NICMOS G141 grism spectra. We describe in detail the
calibration, data reduction and spectrum extraction methods used to produce the
extracted spectra. The quality of the extracted spectra and associated direct
images is demonstrated through comparison with near-IR imaging catalogues and
existing near-IR spectroscopy. The output data products and their associated
metadata are publicly available through a web form at http://hla.stecf.org and
via VO interfaces. In total, 2470 spectra of 1923 unique targets are included
in the current release.


title: Gas-Liquid Nucleation in Two Dimensional System

abstract:
  We study the nucleation of the liquid phase from a supersaturated vapor in
two dimensions (2D). Using different Monte Carlo simulation methods, we
calculate the free energy barrier for nucleation, the line tension and also
investigate the size and shape of the critical nucleus. The study is carried
out at an intermediate level of supersaturation(away from the spinodal limit).
In 2D, a large cut-off in the truncation of the Lennard-Jones (LJ) potential is
required to obtain converged results, whereas low cut-off (say, $2.5\sigma$ is
generally sufficient in three dimensional studies, where $\sigma$ is the LJ
diameter) leads to a substantial error in the values of line tension,
nucleation barrier and characteristics of the critical cluster. It is found
that in 2D, the classical nucleation theory (CNT) fails to provide a reliable
estimate of the free energy barrier. It underestimates the barrier by as much
as 70% at the saturation-ratio S=1.1 (defined as S=P/PC, where PC is the
coexistence pressure at reduced temperature $T^{\star}= 0.427$). Interestingly,
CNT has been found to overestimate the nucleation free energy barrier in three
dimensional (3D)systems near the triple point. In fact, the agreement with CNT
is worse in 2D than in 3D. Moreover, the existing theoretical estimate of the
line tension overestimates the value significantly.


title:
Intrinsic absorption in 3C 279 at GeV-TeV energies and consequences for
  estimates of the EBL

abstract:
  We revisit the limits of the level of the extragalactic background light
(EBL) recently reported by the MAGIC collaboration based on the observed
gamma-ray spectrum of the quasar 3C279, considering the impact of absorption of
high-energy gamma-ray photons inside the broad line region (BLR) of the quasar.
We use the photoionization code CLOUDY to calculate the expected optical-UV
radiation field inside the BLR and the optical depth to gamma-rays for a
relatively extended set of the parameters. We found that the absorption of
gamma-ray photons, though important for the estimate of the true radiative
output of the source, does not produce an important hardening of the spectrum
of 3C279 in the energy band accessible by MAGIC, supporting the method used to
infer the upper limits to the level of the EBL.


title:
Particle current in symmetric exclusion process with time-dependent
  hopping rates

abstract:
  In a recent study, (Jain et al 2007 Phys. Rev. Lett. 99 190601), a symmetric
exclusion process with time-dependent hopping rates was introduced. Using
simulations and a perturbation theory, it was shown that if the hopping rates
at two neighboring sites of a closed ring vary periodically in time and have a
relative phase difference, there is a net DC current which decreases inversely
with the system size. In this work, we simplify and generalize our earlier
treatment. We study a model where hopping rates at all sites vary periodically
in time, and show that for certain choices of relative phases, a DC current of
order unity can be obtained. Our results are obtained using a perturbation
theory in the amplitude of the time-dependent part of the hopping rate. We also
present results obtained in a sudden approximation that assumes large
modulation frequency.


title: Multi-fluid potential in the loop cosmology

abstract:
  The scalar field can behave like a fluid with equation of state
$p_{\phi}=w\rho_{\phi}$, where $w \in [-1,1]$. In this Letter we derive a class
of the scalar field potentials for which $w=$ const. Scalar field with such a
potential can mimic ordinary matter, radiation, cosmic strings, etc. We perform
our calculations in the framework of the loop cosmology with holonomy
corrections. We solve the model analytically for the whole parameter space.
Subsequently, we perform similar consideration for the model with a phantom
field ($w<-1$). We show that scalar field is monotonic function in both cases.
This indicates that it can be treated as a well-defined internal time for these
models. Moreover we perform preliminary studies of the scalar field
perturbations with this potential. We indicate that non-Gaussian features are
present admitting for the possible observational constraints of the model.