title:
A necessary condition for existence of S-matrix outside perturbation
  theory

abstract:
  Using the Maslov--Shvedov method of complex germ, we show that quantum field
theory S-matrix can exist outside perturbation theory in the principal order of
quasiclassical approximation only under the condition that the tangent
symplectic transformation to the evolution operator of non-linear classical
field equation is unitarily implementable in the Fock space. However, the
results of Maslov--Shvedov's book imply that this condition is seemingly always
satisfied.


title: Photon-assisted spin transport in a two-dimensional electron gas

abstract:
  We study spin-dependent transport in a two-dimensional electron gas subject
to an external step-like potential $V(x)$ and irradiated by an electromagnetic
field (EF). In the absence of EF the electronic spectrum splits into spin
sub-bands originating from the "Rashba" spin-orbit coupling. We show that the
resonant interaction of propagating electrons with the component EF parallel to
the barrier induces a \textit{% non-equilibrium dynamic gap} $(2\Delta_{R})$
between the spin sub-bands. Existence of this gap results in coherent spin-flip
processes that lead to a spin-polarized current and a large magnetoresistance,
i.e the spin valve effect. These effects may be used for controlling spin
transport in semiconducting nanostructures, e.g. spin transistors,
spin-blockade devices etc., by variation of the intensity S and frequency
$\omega $ of the external radiation.


title: The Grand View of Physics

abstract:
  Abdus Salam was known for his `grand views', grand views of science as well
as grand views of society. In this talk the grand view of theoretical physics
is put in perspective.


title: Fronts Propagation at the Onset of Plastic Yielding

abstract:
  The existence of a finite threshold, the yield stress, for the onset of
plastic yielding is a universal feature of plasticity. This jamming-unjamming
transition is naturally accounted for by the dynamics of a bistable internal
state field. We show, within the athermal Shear Transformation Zones (STZ)
theory of amorphous plasticity, that the transition is accompanied by the
propagation of plastic fronts. We further show that the mean-field theory
cannot select the velocity of these fronts and go beyond the mean-field
description to include fluctuations and correlations effects, resulting in new
nonlocal terms in the equations. Finally, we demonstrate that the new terms,
with an associated intrinsic lengthscale, provide a velocity selection
mechanism for the plastic fronts.


title: Ground-state fidelity in one-dimensional gapless model

abstract:
  A general relation between quantum phase transitions and the second
derivative of the fidelity (or the "fidelity susceptibility") is proposed. The
validity and the limitation of the fidelity susceptibility in characterizing
quantum phase transitions is thus established. Moreover, based on the
bosonization method, general formulas of the fidelity and the fidelity
susceptibility are obtained for a class of one-dimensional gapless systems
known as the Tomonaga-Luttinger liquid. Applying these formulas to the
one-dimensional spin-1/2 $XXZ$ model, we find that quantum phase transitions,
even of the Beresinskii-Kosterlitz-Thouless type, can be signaled by the
fidelity susceptibility.


title: Strong covalent bonding between two graphene layers

abstract:
  We show that two graphene layers stacked directly on top of each other (AA
stacking) form strong chemical bonds when the distance between planes is 0.156
nm. Simultaneously, C-C in-plane bonds are considerably weakened from partial
double-bond (0.141 nm) to single bond (0.154 nm). This polymorphic form of
graphene bilayer is meta-stable w.r.t. the one bound by van der Waals forces at
a larger separation (0.335 nm) with an activation energy of 0.16 eV/cell.
Similarly to the structure found in hexaprismane, C forms four single bonds in
a geometry mixing 90^{0} and 120^{0} angles. Intermediate separations between
layers can be stabilized under external anisotropic stresses showing a rich
electronic structure changing from semimetal at van der Waals distance, to
metal when compressed, to wide gap semiconductor at the meta-stable minimum.


title: Heat kernel estimates for the Grusin operator

abstract:
  We study the geometry associated to the Grusin operator
G=\Delta_{x}+|x|^{2}\partial_{u}^{2} on \mathbb{R}_{x}^{n}\times\mathbb{R}_{u},
to obtain heat kernel estimates for this operator. The main work is to find the
shortest geodesics connecting two given points in $\mathbb{R}^{n+1}$. This
gives the Carnot-Caratheodory distance d_{CC}, associated to this operator. The
main result in the second part is to give Gaussian bounds for the heat kernel
K_{t} in terms of the Carnot-Caratheodory distance. In particular we obtain the
following estimate
  |k_{t}(\zeta,\eta)|\leq C t^{-\frac{n}{2}-1}\min(1+\frac{d_{CC}(\zeta,\eta)}
{|x+\xi|},1+\frac{d_{CC}(\zeta,\eta)^{2}}{4t})^{\alpha}e^{-\frac{1}{4t}d_{CC}
(\zeta,\eta)^{2}}
  for all $\zeta=(x,u_{1}), \eta=(\xi,u)\in\mathbb{R}^{n+1}$, where $\alpha =
\max{\frac{n}{2}-1,0}$. Here the homogeneous dimension is q=n+2, so that
$\frac{n}{2}-1=\frac{q-4}{2}$. This shows that our result for $n\geq2$
corresponds with the result on the Heisenberg group, which was given by Beals,
Gaveau, Greiner in [1].


title: The influence of self-citation corrections on Egghe's g index

abstract:
  The g index was introduced by Leo Egghe as an improvement of Hirsch's index h
for measuring the overall citation record of a set of articles. It better takes
into account the highly skewed frequency distribution of citations than the h
index. I propose to sharpen this g index by excluding the self-citations. I
have worked out nine practical cases in physics and compare the h and g values
with and without self-citations. As expected, the g index characterizes the
data set better than the h index. The influence of the self-citations appears
to be more significant for the g index than for the h index.


title: Update on Counting Valence Quarks at RHIC

abstract:
  We update our former analysis of the Nuclear Modification Factors (NMF) for
different hadron species at RHIC and LHC. This update is motivated by the new
experimental data from STAR which presents differences with the preliminary
data used to fix some of the parameters in our model. The main change is the
use of AKK fragmentation functions for the hard part of the spectrum and minor
adjustments of the coalescence (soft) contribution. We confirm that observation
of the NMF for the f_0 meson can shed light on its quark composition.


title: Magnetic Field Structures of BL Lac Objects on Decaparsec Scales

abstract:
  Relatively few Very Long Baseline Interferometry (VLBI) polarization
observations have been carried out at 18 cm. The importance of such
observations lies in their ability to reveal information about the jet magnetic
({\bf B}) field structure and the environment of the jet on scales intermediate
between those probed by higher-frequency VLBI and connected-element
interferometers such as the Very Large Array. We have obtained polarization
observations of 34 BL Lac objects with the Very Long Baseline Array (VLBA), at
4 separate wavelengths in the 18-20 cm band. The 18-cm jets typically extend to
tens of parsecs. In some cases, the decaparsec jet is a continuation of the jet
on smaller scales, while in others, we see appreciable bending. We have
constructed Faraday rotation-measure maps and used them to study the jet {\bf
B} field structures and distribution of thermal plasma around the jets. The
Faraday rotation is typically large at these wavelengths, and knowledge of the
rotation-measure distribution is essential to derive the {\bf B} field
structures of the jets. The high sensitivity of these observations to Faraday
rotation makes them an effective tool for studies of possible interactions
between the jets and the media through which they propagate.


title: Note on edge-colored graphs and digraphs without properly colored cycles

abstract:
  We study the following two functions: d(n,c) and $\vec{d}(n,c)$; d(n,c)
($\vec{d}(n,c)$) is the minimum number k such that every c-edge-colored
undirected (directed) graph of order n and minimum monochromatic degree
(out-degree) at least k has a properly colored cycle. Abouelaoualim et al.
(2007) stated a conjecture which implies that d(n,c)=1. Using a recursive
construction of c-edge-colored graphs with minimum monochromatic degree p and
without properly colored cycles, we show that $d(n,c)\ge {1 \over c}(\log_cn
-\log_c\log_cn)$ and, thus, the conjecture does not hold. In particular, this
inequality significantly improves a lower bound on $\vec{d}(n,2)$ obtained by
Gutin, Sudakov and Yeo in 1998.


title: Physical conditions in CaFe interstellar clouds

abstract:
  Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe
clouds. The ionisation equilibrium equations were used to model the column
densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The
chemical composition of CaFe clouds is that of the Solar System and no
depletion of elements onto dust grains is seen. The CaFe clouds have high
electron densities n=1 cm^-3 that leads to high column densities of neutral Ca
and Fe.


title: Hall Effect in Granular Metals: Weak Localization Corrections

abstract:
  We study the effects of localization on the Hall transport in a granular
system at large tunneling conductance $g_{T}\gg 1$ corresponding to the
metallic regime. We show that the first-order in 1/g_T weak localization
correction to Hall resistivity of a two- or three-dimensional granular array
vanishes identically, $\de \rho_{xy}^{WL}=0$. This result is in agreement with
the one for ordinary disordered metals. Being due to an exact cancellation, our
result holds for arbitrary relevant values of temperature T and magnetic field
H, both in the ``homogeneous'' regime of very low T and H corresponding to
ordinary disordered metals and in the ``structure-dependent'' regime of higher
values of T or H.


title: Warping and F-term uplifting

abstract:
  We analyse the effective supergravity model of a warped compactification with
matter on D3 and D7-branes. We find that the main effect of the warp factor is
to modify the F-terms while leaving the D-terms invariant. Hence warped models
with moduli stabilisation and a small positive cosmological constant resulting
from a large warping can only be achieved with an almost vanishing D-term and a
F-term uplifting. By studying string-motivated examples with gaugino
condensation on magnetised D7-branes, we find that even with a vanishing
D-term, it is difficult to achieve a Minkowski minimum for reasonable parameter
choices. When coupled to an ISS sector the AdS vacua is uplifted, resulting in
a small gravitino mass for a warp factor of order 10^-5.


title: Some new Strichartz estimates for the Schr\"odinger equation

abstract:
  We deal with fixed-time and Strichartz estimates for the Schr\"odinger
propagator as an operator on Wiener amalgam spaces. We discuss the sharpness of
the known estimates and we provide some new estimates which generalize the
classical ones. As an application, we present a result on the wellposedness of
the linear Schr\"odinger equation with a rough time dependent potential.


title: Two-eigenfunction correlation in a multifractal metal and insulator

abstract:
  We consider the correlation of two single-particle probability densities
$|\Psi_{E}({\bf r})|^{2}$ at coinciding points ${\bf r}$ as a function of the
energy separation $\omega=|E-E'|$ for disordered tight-binding lattice models
(the Anderson models) and certain random matrix ensembles. We focus on the
models in the parameter range where they are close but not exactly at the
Anderson localization transition. We show that even far away from the critical
point the eigenfunction correlation show the remnant of multifractality which
is characteristic of the critical states. By a combination of the numerical
results on the Anderson model and analytical and numerical results for the
relevant random matrix theories we were able to identify the Gaussian random
matrix ensembles that describe the multifractal features in the metal and
insulator phases. In particular those random matrix ensembles describe new
phenomena of eigenfunction correlation we discovered from simulations on the
Anderson model. These are the eigenfunction mutual avoiding at large energy
separations and the logarithmic enhancement of eigenfunction correlations at
small energy separations in the two-dimensional (2D) and the three-dimensional
(3D) Anderson insulator. For both phenomena a simple and general physical
picture is suggested.


title: Light Scalar Tetraquark Mesons in the QCD Sum Rule

abstract:
  We study the lowest-lying scalar mesons in the QCD sum rule by considering
them as tetraquark states. We find that there are five independent currents for
each state with a certain flavor structure. By forming linear combinations, we
find that some mixed currents give reliable QCD sum rules. Among various
tetraquark currents, we consider those which are constructed by the diquarks
having anti-symmetric and symmetric flavor structures. That the results of the
QCD sum rule derived from the two types of currents are similar suggests that
the tetraquark states can have a large mixing between different flavor
structures.


title: Observations on Gaussian bases for Schrodinger's equation

abstract:
  One of the few methods for generating efficient function spaces for multi-D
Schrodinger eigenproblems is given by Garashchuk and Light in J.Chem.Phys. 114
(2001) 3929. Their Gaussian basis functions are wider and sparser in high
potential regions, and narrower and denser in low ones. We suggest a
modification of their approach based on the following observation: In very
steep potential regions, wide, sparse, Gaussians should be avoided even if
their centers have high potential values. Our numerical results illustrate that
a dramatic improvement in accuracy may be obtained in this way. We also compare
the errors of collocation to those of a Galerkin approach, test a criterion for
scaling Gaussian widths based on deviation from orthogonality of collocation
eigenfunctions, and suggest a criterion for scaling Gaussian widths based on
Hamiltonian trace minimization.


title: Probabilistic validation of homology computations for nodal domains

abstract:
  Homology has long been accepted as an important computable tool for
quantifying complex structures. In many applications, these structures arise as
nodal domains of real-valued functions and are therefore amenable only to a
numerical study based on suitable discretizations. Such an approach immediately
raises the question of how accurate the resulting homology computations are. In
this paper, we present a probabilistic approach to quantifying the validity of
homology computations for nodal domains of random fields in one and two space
dimensions, which furnishes explicit probabilistic a priori bounds for the
suitability of certain discretization sizes. We illustrate our results for the
special cases of random periodic fields and random trigonometric polynomials.


title:
Sum Rules for Total Cross-Sections of Hadron Photo-Production on
  Pseudoscalar Mesons and Octet Baryons

abstract:
  Considering very high energy peripheral electron-hadron scattering with a
production of hadronic state X moving closely to the direction of initial
hadron the Weizs\"acker-Williams like expression, relating the difference of
q^2-dependent differential cross-sections of DIS processes to the convergent
integral over the difference of the total hadron photo-production
cross-sections on hadros, is derived. Then, exploiting analytic properties of
the forward retarded Compton scattering amplitude on the same hadrons, first,
the sum rules are derived bringing into relation hadron electromagnetic form
factors with the difference of the q^2-dependent differential cross-sections of
DIS, then using Weizs\"acker-Williams like expression and taking the derivative
of both sides according to ${\bf q^2}$ for ${\bf q^2} \to 0$ one comes to new
universal hadron sum rules relating hadron static parameters to the convergent
integral over the difference of the total hadron photo-production
cross-sections on hadrons.


title:
Exciton condensate at a total filling factor of 1 in Corbino 2D electron
  bilayers

abstract:
  Magneto-transport and drag measurements on a quasi-Corbino 2D electron
bilayer at the systems total filling factor 1 (v_tot=1) reveal a drag voltage
that is equal in magnitude to the drive voltage as soon as the two layers begin
to form the expected v_tot=1 exciton condensate. The identity of both voltages
remains present even at elevated temperatures of 0.25 K. The conductance in the
current carrying layer vanishes only in the limit of strong coupling between
the two layers and at T->0 K which suggests the presence of an excitonic
circular current.


title: Tachyon Vacuum in Cubic Superstring Field Theory

abstract:
  In this paper we give an exact analytic solution for tachyon condensation in
the modified (picture 0) cubic superstring field theory. We prove the absence
of cohomology and, crucially, reproduce the correct value for the D-brane
tension. The solution is surprising for two reasons: First, the existence of a
tachyon vacuum in this theory has not been definitively established in the
level expansion. Second, the solution {\it vanishes} in the GSO$(-)$ sector,
implying a ``tachyon vacuum'' solution exists even for a {\it BPS} D-brane.


title:
One loop corrections to the mass of self-dual semi-local planar
  topological solitons

abstract:
  A formula is derived that allows the computation of one-loop mass shifts for
self-dual semilocal topological solitons. These extended objects, which in
three spatial dimensions are called semi-local strings, arise in a generalized
Abelian Higgs model with a doublet of complex Higgs fields. Having a mixture of
global, SU(2), and local (gauge), U(1), symmetries, this weird system may seem
bizarre, but it is in fact the bosonic sector of electro-weak theory when the
weak mixing angle is of 90 degrees. The procedure for computing the
semi-classical mass shifts is based on canonical quantization and heat
kernel/zeta function regularization methods.


title: nu_e Disappearance in MiniBooNE

abstract:
  The anomalous excess of low-energy nu_e events measured in the MiniBooNE
experiment is explained through a renormalization of the absolute neutrino flux
and a simultaneous disappearance of the nu_e's in the beam, which is compatible
with that indicated by the results of Gallium radioactive source experiments.
We present the results of the fit of MiniBooNE data (P(nu_e->nu_e) = 0.64 +0.08
-0.07) and the combined fit of MiniBooNE data and the nu_e disappearance
measured in the Gallium radioactive source experiments, which gives
P(nu_e->nu_e) = 0.82 +- 0.04. We show that our interpretation of the data is
also compatible with an old indication in favor of nu_e disappearance found
from the analysis of the results of beam-dump experiments, leading to
P(nu_e->nu_e) = 0.80 +0.03 -0.04.


title:
Stability of steady states in kinetic Fokker-Planck equations for Bosons
  and Fermions

abstract:
  We study a class of nonlinear kinetic Fokker-Planck type equations modeling
quantum particles which obey the Bose-Einstein and Fermi-Dirac statistics,
respectively. We establish the existence of classical solutions in the
perturbative regime and prove exponential convergence towards the equilibrium.


title: Einstein solvmanifolds with a simple Einstein derivation

abstract:
  The structure of a solvable Lie groups admitting an Einstein left-invariant
metric is, in a sense, completely determined by the nilradical of its Lie
algebra. We give an easy-to-check necessary and sufficient condition for a
nilpotent algebra to be an Einstein nilradical whose Einstein derivation has
simple eigenvalues. As an application, we classify filiform Einstein
nilradicals (modulo known classification results on filiform graded Lie
algebras).


title:
Uniform convergence of exact large deviations for renewal reward
  processes

abstract:
  Let (X_n,Y_n) be i.i.d. random vectors. Let W(x) be the partial sum of Y_n
just before that of X_n exceeds x>0. Motivated by stochastic models for neural
activity, uniform convergence of the form $\sup_{c\in I}|a(c,x)\operatorname
{Pr}\{W(x)\gecx\}-1|=o(1)$, $x\to\infty$, is established for probabilities of
large deviations, with a(c,x) a deterministic function and I an open interval.
To obtain this uniform exact large deviations principle (LDP), we first
establish the exponentially fast uniform convergence of a family of renewal
measures and then apply it to appropriately tilted distributions of X_n and the
moment generating function of W(x). The uniform exact LDP is obtained for cases
where X_n has a subcomponent with a smooth density and Y_n is not a linear
transform of X_n. An extension is also made to the partial sum at the first
exceedance time.


title: Side-information Scalable Source Coding

abstract:
  The problem of side-information scalable (SI-scalable) source coding is
considered in this work, where the encoder constructs a progressive
description, such that the receiver with high quality side information will be
able to truncate the bitstream and reconstruct in the rate distortion sense,
while the receiver with low quality side information will have to receive
further data in order to decode. We provide inner and outer bounds for general
discrete memoryless sources. The achievable region is shown to be tight for the
case that either of the decoders requires a lossless reconstruction, as well as
the case with degraded deterministic distortion measures. Furthermore we show
that the gap between the achievable region and the outer bounds can be bounded
by a constant when square error distortion measure is used. The notion of
perfectly scalable coding is introduced as both the stages operate on the
Wyner-Ziv bound, and necessary and sufficient conditions are given for sources
satisfying a mild support condition. Using SI-scalable coding and successive
refinement Wyner-Ziv coding as basic building blocks, a complete
characterization is provided for the important quadratic Gaussian source with
multiple jointly Gaussian side-informations, where the side information quality
does not have to be monotonic along the scalable coding order. Partial result
is provided for the doubly symmetric binary source with Hamming distortion when
the worse side information is a constant, for which one of the outer bound is
strictly tighter than the other one.


title:
On the fraction of intermediate-mass close binaries that explode as
  type-Ia supernovae

abstract:
  Type-Ia supernovae (SNe-Ia) are thought to result from a thermonuclear
runaway in white dwarfs (WDs) that approach the Chandrasekhar limit, either
through accretion from a companion or a merger with another WD. I compile
observational estimates of the fraction eta of intermediate-mass stars that
eventually explode as SNe-Ia, supplement them with several new estimates, and
compare them self-consistently. The estimates are based on five different
methods, each utilising some observable related to the SN-Ia rate, combined
with assumptions regarding the IMF: the ratio of SN-Ia to core-collapse rates
in star-forming galaxies; the SN-Ia rate per unit star-formation rate; the
SN-Ia rate per unit stellar mass; the iron to stellar mass ratio in galaxy
clusters; and the abundance ratios in galaxy clusters. The five methods
indicate that a fraction in the range eta~2-40% of all stars with initial
masses of 3-8 M_sun (the generally assumed SN-Ia progenitors) explode as
SNe-Ia. A fraction of eta~15% is consistent with all five methods for a range
of plausible IMFs. Considering also the binarity fraction among such stars, the
mass ratio distribution, the separation distribution, and duplicity (every
binary can produce only one SN-Ia explosion), this implies that nearly every
intermediate mass close binary ends up as a SN-Ia, or possibly more SNe-Ia than
progenitor systems. Theoretically expected fractions are generally one to two
orders of magnitude lower. The problem could be solved: if all the
observational estimates are in error; or with a ``middle-heavy'' IMF; or by
some mechanism that strongly enhances the efficiency of binary evolution toward
SN-Ia explosion; or by a non-binary origin for SNe-Ia.


title: Near-Infrared Surface Photometry of a Sample of Barred Galaxies

abstract:
  We have obtained deep J and Ks images of a sample of nine barred galaxies in
order to collect a reliable and homogeneous set of images to which N-body
simulations of barred galaxies will be compared. The observations were
performed using the new near-infrared camera available at the 2.1-m telescope
of the Observatorio Astrofisico Guillermo Haro (OAGH) in Cananea, Sonora,
Mexico. We present the results of surface photometry techniques applied to the
observed images, as well as to the deprojected images. These results include
radial profiles of surface brightness (elliptically averaged), colour, position
angle, ellipticity and the b4 Fourier component. In addition, we present
isophotal maps, colour maps, surface brightness profiles along the bar major
and minor axes, characteristic radial scale-lengths and bar length estimates.
We discuss how projection effects can influence these measurements and the
uncertainties introduced by deprojecting galaxy images. We show that analytical
expressions can be used to obtain reliable estimates of deprojected bar
lengths, ellipticities and position angles directly from the observed images.
These expressions are based on the assumption that the outer parts of the bar
are vertically thin, as shown by theoretical work. The usefulness of our data
in addressing issues on bar formation and evolution is also discussed. In
particular, we present results showing a steep drop in the ellipticity profile,
as expected for bar formation processes in which the dark matter halo plays a
fundamental role. Furthermore, we show that the location of this drop is a good
indicator of the end of the bar in strongly barred galaxies, as predicted by
numerical models.


title: Heavy traffic limit for a processor sharing queue with soft deadlines

abstract:
  This paper considers a GI/GI/1 processor sharing queue in which jobs have
soft deadlines. At each point in time, the collection of residual service times
and deadlines is modeled using a random counting measure on the right
half-plane. The limit of this measure valued process is obtained under
diffusion scaling and heavy traffic conditions and is characterized as a
deterministic function of the limiting queue length process. As special cases,
one obtains diffusion approximations for the lead time profile and the profile
of times in queue. One also obtains a snapshot principle for sojourn times.


title:
Violation of the isotropic-$\ell$ approximation in overdoped
  La_{2-x}Sr_xCuO_4

abstract:
  Magnetotransport measurements on the overdoped cuprate La_{1.7}Sr_{0.3}CuO_4
are fitted using the Ong construction and band parameters inferred from
angle-resolved photoemission. Within a band picture, the low temperature Hall
data can only be fitted satisfactorily by invoking strong basal-plane
anisotropy in the mean-free-path $\ell$. This violation of the isotropic-$\ell$
approximation supports a picture of dominant small-angle elastic scattering in
cuprates due to out-of-plane substitutional disorder. We show that both band
anisotropy and anisotropy in the elastic scattering channel strongly
renormalize the Hall coefficient in overdoped La_{2-x}Sr_xCuO_4 over a wide
doping and temperature range.


title: Geometry of the theta divisor of a compactified jacobian

abstract:
  We study the theta divisor of the compactified jacobian of a nodal, possibly
reducible, curve. We compute its irreducible components and give it a geometric
interpretation consistent with the classical Brill-Noether theory of smooth
curves. Some applications on hyperelliptic stable curves are appended.


title:
Improved Laboratory Transition Probabilities for Neutral Chromium and
  Re-determination of the Chromium Abundance for the Sun and Three Stars

abstract:
  Branching fraction measurements from Fourier transform spectra in conjunction
with published radiative lifetimes are used to determine transition
probabilities for 263 lines of neutral chromium. These laboratory values are
employed to derive a new photospheric abundance for the Sun: log $\epsilon$(Cr
I)$_{\odot}$ = 5.64$\pm$0.01 ($\sigma = 0.07$). These Cr I solar abundances do
not exhibit any trends with line strength nor with excitation energy and there
were no obvious indications of departures from LTE. In addition, oscillator
strengths for singly-ionized chromium recently reported by the FERRUM Project
are used to determine: log $\epsilon$(Cr II)$_{\odot}$ = 5.77$\pm$0.03 ($\sigma
= 0.13$). Transition probability data are also applied to the spectra of three
stars: HD 75732 (metal-rich dwarf), HD 140283 (metal-poor subgiant), and CS
22892-052 (metal-poor giant). In all of the selected stars, Cr I is found to be
underabundant with respect to Cr II. The possible causes for this abundance
discrepancy and apparent ionization imbalance are discussed.


title: Electronic and Vibrational Properties of gamma-AlH3

abstract:
  Aluminum hydride (alane) AlH_3 is an important material in hydrogen storage
applications. It is known that AlH_3 exists in multiply forms of polymorphs,
where $\alpha$-AlH_3 is found to be the most stable with a hexagonal structure.
Recent experimental studies on $\gamma$-AlH_3 reported an orthorhombic
structure with a unique double-bridge bond between certain Al and H atoms. This
was not found in $\alpha$-AlH_3 or other polymorphs. Using density functional
theory, we have investigated the energetics, and the structural, electronic,
and phonon vibrational properties for the newly reported $\gamma$-AlH_3
structure. The current calculation concludes that $\gamma$-AlH_3 is less stable
than $\alpha$-AlH_3 by 2.1 KJ/mol. Interesting binding features associated with
the unique geometry of $\gamma$-AlH3 are discussed from the calculated
electronic properties and phonon vibrational modes. The binding of H-s with
higher energy Al-p,d orbitals is enhanced within the double-bridge arrangement,
giving rise to a higher electronic energy for the system. Distinguishable new
features in the vibrational spectrum of $\gamma$-AlH_3 were attributed to the
double-bridge and hexagonal-ring structures.


title: Teaching the Kepler laws for freshmen

abstract:
  We present a natural proof of Kepler's law of ellipses in the spirit of
Euclidean geometry. Moreover we discuss two existing Euclidean geometric
proofs, one by Feynman in hist Lost Lecture from 1964 and the other by Newton
in the Principia of 1687.


title: LDA+Gutzwiller Method for Correlated Electron Systems

abstract:
  Combining the density functional theory (DFT) and the Gutzwiller variational
approach, a LDA+Gutzwiller method is developed to treat the correlated electron
systems from {\it ab-initio}. All variational parameters are self-consistently
determined from total energy minimization. The method is computationally
cheaper, yet the quasi-particle spectrum is well described through kinetic
energy renormalization. It can be applied equally to the systems from weakly
correlated metals to strongly correlated insulators. The calculated results for
SrVO$_3$, Fe, Ni and NiO, show dramatic improvement over LDA and LDA+U.


title:
LBB Stability of a Mixed Discontinuous/Continuous Galerkin Finite
  Element Pair

abstract:
  We introduce a new mixed discontinuous/continuous Galerkin finite element for
solving the 2- and 3-dimensional wave equations and equations of incompressible
flow. The element, which we refer to as P1dg-P2, uses discontinuous piecewise
linear functions for velocity and continuous piecewise quadratic functions for
pressure. The aim of introducing the mixed formulation is to produce a new
flexible element choice for triangular and tetrahedral meshes which satisfies
the LBB stability condition and hence has no spurious zero-energy modes. We
illustrate this property with numerical integrations of the wave equation in
two dimensions, an analysis of the resultant discrete Laplace operator in two
and three dimensions, and a normal mode analysis of the semi-discrete wave
equation in one dimension.


title:
Event-by-event transverse momentum fluctuations in nuclear collisions at
  CERN SPS

abstract:
  The latest NA49 results on event-by-event transverse momentum fluctuations
are presented for central Pb+Pb interactions over the whole SPS energy range
(20A - 158A GeV). Two different methods are applied: evaluating the
$\Phi_{p_{T}}$ fluctuation measure and studying two-particle transverse
momentum correlations. The obtained results are compared to predictions of the
UrQMD model. The results on the energy dependence are compared to the NA49 data
on the system size dependence. The NA61 (SHINE, NA49-future) strategy of
searching of the QCD critical end-point is also discussed.


title: Study of the radiative decay phi to a0(980) gamma with the KLOE detector

abstract:
  A sample of 1.25x10^9 phi decays, collected with the KLOE detector at the
Frascati phi-factory DAFNE at center of mass energy ~ Mphi, has been used to
study the radiative decay phi to eta pi0 gamma. This decay is dominated by phi
to a0(980) gamma. Two decay chains, corresponding to eta to gamma gamma and eta
to pi+ pi- pi0, have been selected. We found respectively: Br(phi to eta pi0
gamma)=(6.92 +/- 0.10 (stat.) +/- 0.20 (syst.))x10^(-5) and (7.19 +/- 0.17
(stat.) +/- 0.24 (syst.))x 10 ^(-5). The eta pi0 invariant mass distributions
have been fitted to obtain the relevant a0(980) parameters.


title:
Estimates for the maximal singular integral in terms of the singular
  integral:the case of even kernels

abstract:
  The purpose of this paper is to describe the smooth homogeneous
Calderon-Zygmund operators for which the maximal singular integral T*f may be
controlled by the singular integral Tf. We consider two types of control. The
first is the L2 estimate of T*f by Tf, namely the estimate of the L2 norm of
T*f by a constant times the L2 norm of Tf. The second is the pointwise estimate
of T*f(x) by a constant times M(Tf)(x), where M denotes the Hardy-Littlewood
maximal operator. Notice that this is an improved variant of Cotlar's
inequality, because the term Mf(x) is missing on the right hand side. Our main
result states that, for even operators, both are equivalent to a purely
algebraic condition formulated in terms of the expansion of the kernel in
spherical harmonics. The condition holds by higher order Riesz transforms,
which then satisfy an improved version of Cotlar's inequality


title: Theory of swimming filaments in viscoelastic media

abstract:
  Motivated by the swimming of sperm in the non-Newtonian fluids of the female
mammalian reproductive tract, we examine the swimming of filaments in the
nonlinear viscoelastic Upper Convected Maxwell model. We obtain the swimming
velocity and hydrodynamic force exerted on an infinitely long cylinder with
prescribed beating pattern. We use these results to examine the swimming of a
simplified sliding-filament model for a sperm flagellum. Viscoelasticity tends
to decrease swimming speed, and changes in the beating patterns due to
viscoelasticity can reverse swimming direction.


title: Hartree-Fock theory for pseudorelativistic atoms

abstract:
  We study the Hartree-Fock model for pseudorelativistic atoms, that is, atoms
where the kinetic energy of the electrons is given by the pseudorelativistic
operator \sqrt{(pc)^2+(mc^2)^2}-mc^2. We prove the existence of a Hartree-Fock
minimizer, and prove regularity away from the nucleus and pointwise exponential
decay of the corresponding orbitals.


title:
Correlation Effects in Wave Function Mapping of Molecular Beam Epitaxy
  Grown Quantum Dots

abstract:
  We investigate correlation effects in the regime of a few electrons in
uncapped InAs quantum dots by tunneling spectroscopy and wave function (WF)
mapping at high tunneling currents where electron-electron interactions become
relevant. Four clearly resolved states are found, whose approximate symmetries
are roughly s and p, in order of increasing energy. Because the major axes of
the p-like states coincide, the WF sequence is inconsistent with the imaging of
independent-electron orbitals. The results are explained in terms of many-body
tunneling theory, by comparing measured maps with those calculated by taking
correlation effects into account.


title: Thermal conductivity of ions in a neutron star envelope

abstract:
  We analyze the thermal conductivity of ions (equivalent to the conductivity
of phonons in crystalline matter) in a neutron star envelope.
  We calculate the ion/phonon thermal conductivity in a crystal of atomic
nuclei using variational formalism and performing momentum-space integration by
Monte Carlo method. We take into account phonon-phonon and phonon-electron
scattering mechanisms and show that phonon-electron scattering dominates at not
too low densities. We extract the ion thermal conductivity in ion liquid or gas
from literature.
  Numerical values of the ion/phonon conductivity are approximated by
analytical expressions, valid for T>10^5 K and 10^5 g cm^-3 < \rho < 10^14 g
cm^-3. Typical magnetic fields B~10^12 G in neutron star envelopes do not
affect this conductivity although they strongly reduce the electron thermal
conductivity across the magnetic field. The ion thermal conductivity remains
much smaller than the electron conductivity along the magnetic field. However,
in the outer neutron star envelope it can be larger than the electron
conductivity across the field, that is important for heat transport across
magnetic field lines in cooling neutron stars. The ion conductivity can greatly
reduce the anisotropy of heat conduction in outer envelopes of magnetized
neutron stars.


title: New nuclear three-body clusters \phi{NN}

abstract:
  Binding energies of three-body systems of the type \phi+2N are estimated. Due
to the strong attraction between \phi-meson and nucleon, suggested in different
approaches, bound states can appear in systems like \phi+np (singlet and
triplet) and \phi+pp. This indicates the principal possibility of the formation
of new nuclear clusters.


title: Measurement of the eta mass at KLOE

abstract:
  An integrated luminosity of 410 pb^(-1), corresponding to ~ 17 million of eta
events, has been analyzed to measure the eta mass using the decay eta to gamma
gamma. The measurement is insensitive to the calorimeter energy calibration and
the systematic error on the measurement is dominated by the uniformity of the
detector response. As a cross check of the method the pi0 mass from the decay
phi to pi0 gamma, pi0 to gamma gamma has been measured and it is in agreement
with the most accurate previous determinations. The result obtained is m(eta) =
547.873 +/- 0.007 (stat.) +/- 0.031 (syst.) MeV, that is today best measurement
of the eta mass.


title: Integrality of instanton numbers

abstract:
  We prove the results announced in a joint paper (arXiv:hep-th/0603106) with
Maxim Kontsevich and Albert Schwarz.


title: Nonlinear Matroid Optimization and Experimental Design

abstract:
  We study the problem of optimizing nonlinear objective functions over
matroids presented by oracles or explicitly. Such functions can be interpreted
as the balancing of multi-criteria optimization. We provide a combinatorial
polynomial time algorithm for arbitrary oracle-presented matroids, that makes
repeated use of matroid intersection, and an algebraic algorithm for vectorial
matroids.
  Our work is partly motivated by applications to minimum-aberration
model-fitting in experimental design in statistics, which we discuss and
demonstrate in detail.


title: Control of sub-excitable waves in neural networks by nonlocal coupling

abstract:
  Transient wave forms in neural networks with diffusive and nonlocal coupling
have attracted particular interest because they may mediate recruitment of
healthy cortical tissue into a pathological state during migraine. To
investigate this process, we use a reaction-diffusion system of
inhibitor-activator type as a generic model of pathological wave propagation
and set it close to bifurcation in the sub-excitable regime. We report the
influence of various nonlocal connectivity schemes on wave propagation. Wave
propagation can be suppressed with cross coupling inhibitor and activator for
both positive and negative coupling strength K, depending on the connection
length d. The area in the parameter plane (d,K) where this control goal is
achieved resembles a Mexican-hat-type network connectivity. Our results suggest
that nonlocal synaptic transmission can control wave propagation, which may be
of therapeutic value.


title:
Nuclear equation of state at high baryonic density and compact star
  constraints

abstract:
  A mean field calculation is carried out to obtain the equation of state (EoS)
of nuclear matter from a density dependent M3Y interaction (DDM3Y). The energy
per nucleon is minimized to obtain ground state of the symmetric nuclear matter
(SNM). The constants of density dependence of the effective interaction are
obtained by reproducing the saturation energy per nucleon and the saturation
density of SNM. The energy variation of the exchange potential is treated
properly in the negative energy domain of nuclear matter. The EoS of SNM, thus
obtained, is not only free from the superluminosity problem but also provides
excellent estimate of nuclear incompressibility. The EoS of asymmetric nuclear
matter is calculated by adding to the isoscalar part, the isovector component
of M3Y interaction. The SNM and pure neutron matter EoS are used to calculate
the nuclear symmetry energy which is found to be consistent with that extracted
from the isospin diffusion in heavy-ion collisions at intermediate energies.
The $\beta$ equilibrium proton fraction calculated from the symmetry energy and
related theoretical findings are consistent with the constraints derived from
the observations on compact stars.


title:
Semiparametrically efficient rank-based inference for shape I. optimal
  rank-based tests for sphericity

abstract:
  We propose a class of rank-based procedures for testing that the shape matrix
$\mathbf{V}$ of an elliptical distribution (with unspecified center of
symmetry, scale and radial density) has some fixed value ${\mathbf{V}}_0$; this
includes, for ${\mathbf{V}}_0={\mathbf{I}}_k$, the problem of testing for
sphericity as an important particular case. The proposed tests are invariant
under translations, monotone radial transformations, rotations and reflections
with respect to the estimated center of symmetry. They are valid without any
moment assumption. For adequately chosen scores, they are locally
asymptotically maximin (in the Le Cam sense) at given radial densities. They
are strictly distribution-free when the center of symmetry is specified, and
asymptotically so when it must be estimated. The multivariate ranks used
throughout are those of the distances--in the metric associated with the null
value ${\mathbf{V}}_0$ of the shape matrix--between the observations and the
(estimated) center of the distribution. Local powers (against elliptical
alternatives) and asymptotic relative efficiencies (AREs) are derived with
respect to the adjusted Mauchly test (a modified version of the Gaussian
likelihood ratio procedure proposed by Muirhead and Waternaux [Biometrika 67
(1980) 31--43]) or, equivalently, with respect to (an extension of) the test
for sphericity introduced by John [Biometrika 58 (1971) 169--174]. For Gaussian
scores, these AREs are uniformly larger than one, irrespective of the actual
radial density. Necessary and/or sufficient conditions for consistency under
nonlocal, possibly nonelliptical alternatives are given. Finite sample
performances are investigated via a Monte Carlo study.


title: Theory of spin qubits in nanostructures

abstract:
  We review recent advances on the theory of spin qubits in nanostructures. We
focus on four selected topics. First, we show how to form spin qubits in the
new and promising material graphene. Afterwards, we discuss spin relaxation and
decoherence in quantum dots. In particular, we demonstrate how charge
fluctations in the surrounding environment cause spin decay via spin--orbit
coupling. We then turn to a brief overview of how one can use electron-dipole
spin resonance (EDSR) to perform single spin rotations in quantum dots using an
oscillating electric field. The final topic we cover is the spin-spin coupling
via spin-orbit interaction which is an alternative to the usual spin-spin
coupling via the Heisenberg exchange interaction.


title: Preliminary measurement of Gamma(Ke2)/Gamma(Km2) at KLOE

abstract:
  A preliminary measurement of RK = Gamma(Ke2)/Gamma(Km2) at the KLOE
experiment is discussed. The result, RK = (2.55+-0.05+-0.05)x 10^-5, is based
on 1.7 fb^-1 of luminosity integrated on the phi-meson peak at the Frascati
e^+e^- collider DAFNE, corresponding to ~8000 observed Ke2 events. Perspectives
on the methods planned to improve both the statistical and the systematic
errors are briefly outlined.


title: Conceptual Design of a Micron-Scale Atomic Clock

abstract:
  A theoretical proposal for reducing an entire atomic clock to micron
dimensions. A phosphorus or nitrogen atom is introduced into a fullerene cage.
This endohedral fullerene is then coated with an insulating shell and a number
of them are deposited as a thin layer on a silicon chip. Next to this layer a
GMR sensor is fabricated which is close to the endohedral fullerenes. This GMR
sensor measures oscillating magnetic fields on the order of micro-gauss from
the nuclear spins varying at the frequency of the hyperfine transition (413 MHz
frequency). Given the micron scale and simplicity of this system only a few
transistors are needed to control the waveforms and to perform digital
clocking. This new form of atomic clock exhibits extremely low power (nano
watts), high vibration and shock resistance, stability on the order of 10^{-9},
and is compatible with MEMS fabrication and chip integration. As GMR sensors
continue to improve in sensitivity the stability of this form of atomic clock
will increase proportionately.


title: Holographic Dark Energy Model with Modified Generalized Chaplygin Gas

abstract:
  We present a holographic dark energy model of the universe considering
modified generalized Chaplygin gas (GCG). The modified GCG behaves as an
ordinary barotropic fluid in the early epoch when the universe was tiny but
behaves subsequently as a $\Lambda$CDM model at late epoch. An equivalent model
with scalar field is obtained here by constructing the corresponding potential.
The holographic dark energy is identified with the modified GCG and we
determine the corresponding holographic dark energy field and its potential.
The stability of the holographic dark energy in this case is also discussed.


title: The First Swift BAT Gamma-Ray Burst Catalog

abstract:
  We present the first Swift Burst Alert Telescope (BAT) catalog of gamma-ray
bursts (GRBs), which contains bursts detected by the BAT between 2004 December
19 and 2007 June 16. This catalog (hereafter BAT1 catalog) contains burst
trigger time, location, 90% error radius, duration, fluence, peak flux, and
time averaged spectral parameters for each of 237 GRBs, as measured by the BAT.
The BAT-determined position reported here is within 1.75' of the Swift X-ray
Telescope (XRT)-determined position for 90% of these GRBs. The BAT T_90 and
T_50 durations peak at 80 and 20 seconds, respectively. From the
fluence-fluence correlation, we conclude that about 60% of the observed peak
energies, Epeak, of BAT GRBs could be less than 100 keV. We confirm that GRB
fluence to hardness and GRB peak flux to hardness are correlated for BAT bursts
in analogous ways to previous missions' results. The correlation between the
photon index in a simple power-law model and Epeak is also confirmed. We also
report the current status for the on-orbit BAT calibrations based on
observations of the Crab Nebula.


title: GRI: focusing on the evolving violent Universe

abstract:
  The Gamma-Ray Imager (GRI) is a novel mission concept that will provide an
unprecedented sensitivity leap in the soft gamma-ray domain by using for the
first time a focusing lens built of Laue diffracting crystals. The lens will
cover an energy band from 200 - 1300 keV with an effective area reaching 600
cm2. It will be complemented by a single reflection multilayer coated mirror,
extending the GRI energy band into the hard X-ray regime, down to ~10 keV. The
concentrated photons will be collected by a position sensitive pixelised CZT
stack detector. We estimate continuum sensitivities of better than 10^-7
ph/cm2/s/keV for a 100 ks exposure; the narrow line sensitivity will be better
than 3 x 10^-6 ph/cm2/s for the same integration time. As focusing instrument,
GRI will have an angular resolution of better than 30 arcsec within a field of
view of roughly 5 arcmin - an unprecedented achievement in the gamma-ray
domain. Owing to the large focal length of 100 m of the lens and the mirror,
the optics and detector will be placed on two separate spacecrafts flying in
formation in a high elliptical orbit. R&D work to enable the lens focusing
technology and to develop the required focal plane detector is currently
underway, financed by ASI, CNES, ESA, and the Spanish Ministery of Education
and Science. The GRI mission is proposed as class M mission for ESA's Cosmic
Vision 2015-2025 program. GRI will allow studies of particle acceleration
processes and explosion physics in unprecedented detail, providing essential
clues on the innermost nature of the most violent and most energetic processes
in the Universe.


title: Forbidden patterns and shift systems

abstract:
  The scope of this paper is two-fold. First, to present to the researchers in
combinatorics an interesting implementation of permutations avoiding
generalized patterns in the framework of discrete-time dynamical systems.
Indeed, the orbits generated by piecewise monotone maps on one-dimensional
intervals have forbidden order patterns, i.e., order patterns that do not occur
in any orbit. The allowed patterns are then those patterns avoiding the
so-called forbidden root patterns and their shifted patterns. The second scope
is to study forbidden patterns in shift systems, which are universal models in
information theory, dynamical systems and stochastic processes. Due to its
simple structure, shift systems are accessible to a more detailed analysis and,
at the same time, exhibit all important properties of low-dimensional chaotic
dynamical systems (e.g., sensitivity to initial conditions, strong mixing and a
dense set of periodic points), allowing to export the results to other
dynamical systems via order-isomorphisms.


title:
On the role of stochastic Fermi acceleration in setting the dissipation
  scale of turbulence in the interstellar medium

abstract:
  We consider the dissipation by Fermi acceleration of magnetosonic turbulence
in the Reynolds Layer of the interstellar medium. The scale in the cascade at
which electron acceleration via stochastic Fermi acceleration (STFA) becomes
comparable to further cascade of the turbulence defines the inner scale. For
any magnetic turbulent spectra equal to or shallower than Goldreich-Sridhar
this turns out to be $\ge 10^{12}$cm, which is much larger than the shortest
length scales observed in radio scintillation measurements. While STFA for such
spectra then contradict models of scintillation which appeal directly to an
extended, continuous turbulent cascade, such a separation of scales is
consistent with the recent work of \citet{Boldyrev2} and \citet{Boldyrev3}
suggesting that interstellar scintillation may result from the passage of radio
waves through the galactic distribution of thin ionized boundary surfaces of
HII regions, rather than density variations from cascading turbulence. The
presence of STFA dissipation also provides a mechanism for the non-ionizing
heat source observed in the Reynolds Layer of the interstellar medium
\citep{Reynolds}. STFA accommodates the proper heating power, and the input
energy is rapidly thermalized within the low density Reynolds layer plasma.


title:
Ground state properties of a homogeneous 2D system of Bosons with
  dipolar interactions

abstract:
  The ground-state phase properties of a two-dimensional Bose system with
dipole-dipole interactions is studied by means of quantum Monte Carlo
techniques. Limitations of mean-field theory in a two-dimensional geometry are
discussed. A quantum phase transition from gas to solid is found. Crystal is
tested for existence of a supersolid in the vicinity of the phase transition.
Existence of mesoscopic analogue of the off-diagonal long-range order is shown
in the one-body density matrix in a finite-size crystal. Non-zero superfluid
fraction is found in a finite-size crystal, the signal being dramatically
increased in presence of vacancies.


title:
Measurements of the form-factors slopes of KL -> pi mu nu decay with the
  KLOE Detector

abstract:
  We present a measurement of the K-$\pi$ form-factor parameters for the decay
  \klpmn. We use 328 pb^{-1} of data collected in 2001 and 2002, corresponding
to
  $\sim $ 1.8 million \semil events.
  Measurements of semileptonic form factors provide information about the
dynamics of the strong interaction and are necessary for evaluation of the
phase-space integral $I^\mu_K$ needed to measure the CKM matrix element
$|V_{us}|$ for \klpmn decays and to test lepton universality in kaon decays.
Using a new parameterization for the vector and scalar form factors we find
$\lambda_+$=\pt(25.6\pm 0.4_{\rm{stat.}}\pm 0.3_{\rm{syst.}}),-3, and
$\lambda_0$=\pt(14.3\pm 1.7_{\rm{stat.}}\pm 1.1_{\rm{stat.}}),-3,. In the more
usual quadratic expansion of the form factor the above result is corresponds to
$\lambda'_+=\lambda_+$, $\lambda''_+=2\lambda^2_+$, $\lambda'_0=\lambda_0$ and
$\lambda''_0=(\lambda^2_0+0.000416)/2$. Our results, together with recent
lattice calculations of $f_\pi$, $f_K$ and $f(0)$, satisfy the Callan-Trieman
relation.


title:
Inverse Scattering Theory for One-Dimensional Schroedinger Operators
  with Steplike Periodic Potentials

abstract:
  We develop direct and inverse scattering theory for one-dimensional
Schroedinger operators with steplike potentials which are asymptotically close
to different finite-gap periodic potentials on different half-axes. We give a
complete characterization of the scattering data, which allow unique
solvability of the inverse scattering problem in the class of perturbations
with finite second moment.


title: Generating trees for permutations avoiding generalized patterns

abstract:
  We construct generating trees with one, two, and three labels for some
classes of permutations avoiding generalized patterns of length 3 and 4. These
trees are built by adding at each level an entry to the right end of the
permutation, which allows us to incorporate the adjacency condition about some
entries in an occurrence of a generalized pattern. We use these trees to find
functional equations for the generating functions enumerating these classes of
permutations with respect to different parameters. In several cases we solve
them using the kernel method and some ideas of Bousquet-M\'elou. We obtain
refinements of known enumerative results and find new ones.


title:
A Study of the Radiative KL->pi nu e (g) Decay and Possible Osservation
  of Direct Photon Emission with the KLOE Detector

abstract:
  We present the measurement of the ratio R =
\frac{\Gamma(\keg;\Estar>30\mev,\qstar>20^\circ)}{\Gamma(\kegf)} and a first
measurement of the direct emission contribution for the same process. We use
328 pb^{-1} of data collected at \kloe in 2001 and 2002, corresponding to about
3 million of \kegf events and about 9 thousand \keg radiative events. Our
result is R= (924 \pm 23_{stat} \pm 16_{syst})10^{-5} for the branching ratio
and X =-2.3\pm 1.3_{stat}\pm 1.4_{syst} for the parameter describing direct
emission.


title: Ionized and neutral gas in the peculiar star/cluster complex in NGC 6946

abstract:
  The characteristics of ionized and HI gas in the peculiar star/cluster
complex in NGC 6946, obtained with the 6-m telescope (BTA) SAO RAS, the Gemini
North telescope, and the Westerbork Synthesis Radio Telescope (WSRT), are
presented. The complex is unusual as hosting a super star cluster, the most
massive known in an apparently non-interacting giant galaxy. It contains a
number of smaller clusters and is bordered by a sharp C-shaped rim. We found
that the complex is additionally unusual in having peculiar gas kinematics. The
velocity field of the ionized gas reveals a deep oval minimum, ~300 pc in size,
centered 7" east of the supercluster. The Vr of the ionized gas in the dip
center is 100 km/s lower than in its surroundings, and emission lines within
the dip appear to be shock excited. This dip is near the center of an HI hole
and a semi-ring of HII regions. The HI (and less certainly, HII) velocity
fields reveal expansion, with the velocity reaching ~30 km/s at a distance
about 300 pc from the center of expansion, which is near the deep minimum
position. The super star cluster is at the western rim of the minimum. The
sharp western rim of the whole complex is plausibly a manifestation of a
regular dust arc along the complex edge. Different hypotheses about the complex
and the Vr depression origins are discussed, including a HVC/dark mini-halo
impact, a BCD galaxy merging, and a gas outflow due to release of energy from
the supercluster stars.


title: Coherent spin rotations in open driven double quantum dots

abstract:
  We analyze the charge and spin dynamics in a DC biased double quantum dot
driven by crossed DC and AC magnetic fields. In this configuration, spatial
delocalization due to inter-dot tunnel competes with intra-dot spin rotations
induced by the time dependent magnetic field, giving rise to a complicated time
dependent behavior of the tunnelling current. When the Zeeman splitting has the
same value in both dots and spin flip is negligible, the electrons remain in
the triplet subspace (dark subspace) performing coherent spin rotations and the
current does not flow. This electronic trapping is removed either by finite
spin relaxation or when the Zeeman splitting is different in each quantum dot.
In the first case, our results show that measuring the current will allow to
get information on the spin relaxation time. In the last case, we will show
that applying a resonant bichromatic magnetic field, the electrons become
trapped in a coherent superposition of states and electronic transport is
blocked. Then, manipulating AC magnetic fields, electrons are driven to perform
coherent spin rotations which can be unambiguously detected by direct
measurement of the tunneling current.


title: Special Fuzzy Matrices for Social Scientists

abstract:
  This book introduces special classes of Fuzzy and Neutrosophic matrices.
These special classes of matrices are used in the construction of multi-expert
special fuzzy models using FCM, FRM and FRE and their Neutorosophic analogues
(simultaneous or otherwise, according to ones need). Using the six basic
models, we have constructed a multi-expert multi-model called the Super Special
Hexagonal Fuzzy and Neutrosophic model.
  Given any special input vector, these models can give the resultant using
special operations. When coupled with computer programming, these operations
can give the solution within a reasonable time period. Such multi-expert
multi-model systems are not only a boon to social scientists, but also to
anyone who wants to use Fuzzy or Neutrosophic models.


title:
Indication of multiscaling in the volatility return intervals of stock
  markets

abstract:
  The distribution of the return intervals $\tau$ between volatilities above a
threshold $q$ for financial records has been approximated by a scaling
behavior. To explore how accurate is the scaling and therefore understand the
underlined non-linear mechanism, we investigate intraday datasets of 500 stocks
which consist of the Standard & Poor's 500 index. We show that the cumulative
distribution of return intervals has systematic deviations from scaling. We
support this finding by studying the m-th moment $\mu_m \equiv
<(\tau/<\tau>)^m>^{1/m}$, which show a certain trend with the mean interval
$<\tau>$. We generate surrogate records using the Schreiber method, and find
that their cumulative distributions almost collapse to a single curve and
moments are almost constant for most range of $<\tau>$. Those substantial
differences suggest that non-linear correlations in the original volatility
sequence account for the deviations from a single scaling law. We also find
that the original and surrogate records exhibit slight tendencies for short and
long $<\tau>$, due to the discreteness and finite size effects of the records
respectively. To avoid as possible those effects for testing the multiscaling
behavior, we investigate the moments in the range $10<<\tau>\leq100$, and find
the exponent $\alpha$ from the power law fitting $\mu_m\sim<\tau>^\alpha$ has a
narrow distribution around $\alpha\neq0$ which depend on m for the 500 stocks.
The distribution of $\alpha$ for the surrogate records are very narrow and
centered around $\alpha=0$. This suggests that the return interval distribution
exhibit multiscaling behavior due to the non-linear correlations in the
original volatility.


title: About Bianchi I with VSL

abstract:
  In this paper we study how to attack, through different techniques, a perfect
fluid Bianchi I model with variable G,c and Lambda, but taking into account the
effects of a $c$-variable into the curvature tensor. We study the model under
the assumption,div(T)=0. These tactics are: Lie groups method (LM), imposing a
particular symmetry, self-similarity (SS), matter collineations (MC) and
kinematical self-similarity (KSS). We compare both tactics since they are quite
similar (symmetry principles). We arrive to the conclusion that the LM is too
restrictive and brings us to get only the flat FRW solution. The SS, MC and KSS
approaches bring us to obtain all the quantities depending on \int c(t)dt.
Therefore, in order to study their behavior we impose some physical
restrictions like for example the condition q<0 (accelerating universe). In
this way we find that $c$ is a growing time function and Lambda is a decreasing
time function whose sing depends on the equation of state, w, while the
exponents of the scale factor must satisfy the conditions
$\sum_{i=1}^{3}\alpha_{i}=1$ and $\sum_{i=1}^{3}\alpha_{i}^{2}<1,$
$\forall\omega$, i.e. for all equation of state$,$ relaxing in this way the
Kasner conditions. The behavior of $G$ depends on two parameters, the equation
of state $\omega$ and $\epsilon,$ a parameter that controls the behavior of
$c(t),$ therefore $G$ may be growing or decreasing.We also show that through
the Lie method, there is no difference between to study the field equations
under the assumption of a $c-$var affecting to the curvature tensor which the
other one where it is not considered such effects.Nevertheless, it is essential
to consider such effects in the cases studied under the SS, MC, and KSS
hypotheses.


title: Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties

abstract:
  We use a modified version of the halo-based group finder developed by Yang et
al. to select galaxy groups from the Sloan Digital Sky Survey (SDSS DR4). In
the first step, a combination of two methods is used to identify the centers of
potential groups and to estimate their characteristic luminosity. Using an
iterative approach, the adaptive group finder then uses the average
mass-to-light ratios of groups, obtained from the previous iteration, to assign
a tentative mass to each group. This mass is then used to estimate the size and
velocity dispersion of the underlying halo that hosts the group, which in turn
is used to determine group membership in redshift space. Finally, each
individual group is assigned two different halo masses: one based on its
characteristic luminosity, and the other based on its characteristic stellar
mass. Applying the group finder to the SDSS DR4, we obtain 301237 groups in a
broad dynamic range, including systems of isolated galaxies. We use detailed
mock galaxy catalogues constructed for the SDSS DR4 to test the performance of
our group finder in terms of completeness of true members, contamination by
interlopers, and accuracy of the assigned masses. This paper is the first in a
series and focuses on the selection procedure, tests of the reliability of the
group finder, and the basic properties of the group catalogue (e.g. the
mass-to-light ratios, the halo mass to stellar mass ratios, etc.). The group
catalogues including the membership of the groups are available at
http://gax.shao.ac.cn/data/Group.html and
http://www.astro.umass.edu/~xhyang/Group.html


title: Using rotation rates to probe age spreads in the Orion Nebula Cluster

abstract:
  The radii of young pre-main-sequence (PMS) stars in the Orion Nebula Cluster
(ONC) have been estimated using their rotation periods and projected equatorial
velocities. Stars at a given effective temperature have a spread in their
geometrically estimated projected radii that is larger than can be accounted
for with a coeval model, observational uncertainties and randomly oriented
rotation axes. It is shown that the required dispersion in radius (a factor of
2-3 full width half maximum) can be modelled in terms of a spread in stellar
ages larger than the median age of the cluster, although the detailed star
formation history cannot be uniquely determined using present data. This
technique is relatively free from systematic uncertainties (binarity,
extinction, variability, distance) that have hampered previous studies of the
ONC star formation history using the conventional Hertzsprung-Russell diagram.
However, the current ONC rotational data are biased against low luminosity
objects, so the deduced dispersions in radius and inferred age are probably
underestimates. In particular, the ages of a tail of PMS stars that appear to
be >=10Myr old in the Hertzsprung-Russell diagram cannot be verified with
present data. If projected equatorial velocities were measured for these
objects it could easily be checked whether their radii are correspondingly
smaller than the bulk of the ONC population.


title:
Subnanosecond Ellipticity Detector for Laser Radiation (second version,
  extended)

abstract:
  Two types of room temperature detectors of terahertz laser radiation have
been developed which allow in an all-electric manner to determine the plane of
polarization of linearly polarized radiation and the Stokes parameters of
elliptically polarized radiation, respectively. The operation of the detectors
is based on photogalvanic effects in semiconductor quantum well structures of
low symmetry. The photogalvanic effects have nanoseconds time constants at room
temperature making a high time resolution of the polarization detectors
possible.


title:
Active Set and EM Algorithms for Log-Concave Densities Based on Complete
  and Censored Data

abstract:
  We develop an active set algorithm for the maximum likelihood estimation of a
log-concave density based on complete data. Building on this fast algorithm, we
indidate an EM algorithm to treat arbitrarily censored or binned data.


title:
Renormalization Group and Black Hole Production in Large Extra
  Dimensions

abstract:
  It has been suggested that the existence of a non-Gaussian fixed point in
general relativity might cure the ultraviolet problems of this theory. Such a
fixed point is connected to an effective running of the gravitational coupling.
We calculate the effect of the running gravitational coupling on the black hole
production cross section in models with large extra dimensions.


title:
OB Associations, Wolf-Rayet Stars, and the Origin of Galactic Cosmic
  Rays

abstract:
  We have measured the isotopic abundances of neon and a number of other
species in the galactic cosmic rays (GCRs) using the Cosmic Ray Isotope
Spectrometer (CRIS) aboard the ACE spacecraft. Our data are compared to recent
results from two-component Wolf-Rayet (WR) models. The three largest deviations
of galactic cosmic ray isotope ratios from solar-system ratios predicted by
these models, 12C/16O, 22Ne/20Ne, and 58Fe/56Fe, are very close to those
observed. All of the isotopic ratios that we have measured are consistent with
a GCR source consisting of ~20% of WR material mixed with ~80% material with
solar-system composition. Since WR stars are evolutionary products of OB stars,
and most OB stars exist in OB associations that form superbubbles, the good
agreement of our data with WR models suggests that OB associations within
superbubbles are the likely source of at least a substantial fraction of GCRs.
In previous work it has been shown that the primary 59Ni (which decays only by
electron-capture) in GCRs has decayed, indicating a time interval between
nucleosynthesis and acceleration of >10^5 yr.In this paper we suggest a
scenario that should allow much of the 59Ni to decay in the OB association
environment and conclude that the hypothesis of the OB association origin of
cosmic rays appears to be viable.


title: On admissible rank one local systems

abstract:
  A rank one local system $\LL$ on a smooth complex algebraic variety $M$ is
1-admissible if the dimension of the first cohomology group $H^1(M,\LL)$ can be
computed from the cohomology algebra $H^*(M,\C)$ in degrees $\leq 2$. Under the
assumption that $M$ is 1-formal, we show that all local systems, except
finitely many, on a non-translated irreducible component $W$ of the first
characteristic variety $\V_1(M)$ are 1-admissible, see Proposition 3.1. The
same result holds for local systems on a translated component $W$, but now
$H^*(M,\C)$ should be replaced by $H^*(M_0,\C)$, where $M_0$ is a Zariski open
subset obtained from $M$ by deleting some hypersurfaces determined by the
translated component $W$, see Theorem 4.3.


title:
Comparing a model of cosmic ray production in the supernova remnant RX
  J1713.7-3946 with observations

abstract:
  Explicitly time-dependent, nonlinear kinetic theory of cosmic ray (CR)
acceleration in supernova remnants (SNRs) has been employed to investigate the
properties of SNR RX J1713.7-3946. Observations of the nonthermal radio and
X-ray emission spectra as well as earlier H.E.S.S. measurements of the very
high energy $\gamma$-ray emission were used to constrain the astronomical and
the particle acceleration parameters of the system. The model assumes that the
object was a core collapse supernova (SN) with a massive progenitor, has an age
of $\approx 1600$ yr and is at a distance of $\approx 1$ kpc. It is shown that
an efficient production of nuclear CRs, leading to strong shock modification
and a large downstream magnetic field strength $B_{\mathrm{d}}\sim100$ $\mu$G,
can reproduce the observed synchrotron emission from radio to X-ray frequencies
together with the \gr spectral characteristics as observed by the H.E.S.S.
telescopes. Small-scale filamentary structures observed in nonthermal X-rays
provide empirical confirmation for this field amplification scenario which
leads to a strong depression of the inverse Compton and Bremsstrahlung fluxes.
The results are compared with the latest H.E.S.S. observations.


title:
Quasiparticle bands in cuprates by quantum chemical methods: towards an
  ab initio description of strong electron correlations

abstract:
  Realistic electronic-structure calculations for correlated Mott insulators
are notoriously hard. Here we present an ab initio multiconfiguration scheme
that adequately describes strong correlation effects involving Cu 3d and O 2p
electrons in layered cuprates. In particular, the O 2p states giving rise to
the Zhang-Rice band are explicitly considered. Renormalization effects due to
nonlocal spin interactions are also treated consistently. We show that the
dispersion of the lowest band observed in photoemission is reproduced with
quantitative accuracy. Additionally, the evolution of the Fermi surface with
doping follows directly from our ab initio data. Our results thus open a new
avenue for the first-principles investigation of the electronic structure of
correlated Mott insulators.


title:
Implications of Shock Wave Experiments with Precompressed Materials for
  Giant Planet Interiors

abstract:
  This work uses density functional molecular dynamics simulations of fluid
helium at high pressure to examine how shock wave experiments with
precompressed samples can help characterizing the interior of giant planets. In
particular, we analyze how large of a precompression is needed to probe a
certain depth in a planet's gas envelope. We find that precompressions of up to
0.1, 1.0, 10, or 100 GPa are needed to characterized 2.5, 5.9, 18, to 63% of
Jupiter's envelope by mass.


title: Secondary resonances of co-orbital motions

abstract:
  The size distribution of the stability region around the Lagrangian point L4
is investigated in the elliptic restricted three-body problem as the function
of the mass parameter and the orbital eccentricity of the primaries. It is
shown that there are minimum zones in the size distribution of the stability
regions, and these zones are connected with secondary resonances between the
frequencies of librational motions around L4. The results can be applied to
hypothetical Trojan planets for predicting values of the mass parameter and the
eccentricity for which such objects can be expected or their existence is less
probable.


title:
Comments on the Reliability of Lawson and Hanson's Linear Distance
  Programming Algorithm: Subroutine LDP

abstract:
  This brief paper: (1) Discusses strategies to generate random test cases that
can be used to extensively test any Linear Distance Program (LDP) software. (2)
Gives three numerical examples of input cases generated by this strategy that
cause problems in the Lawson and Hanson LDP module. (3) Proposes, as a standard
matter of acceptable implementation procedures, that (unless it is done
internally in the software itself, but, in general, this seems to be much rarer
than one would expect) all users should test the returned output from any LDP
module for self-consistency since it incurs only a small amount of added
computational overhead and it is not hard to do.


title: Laser tweezers for atomic solitons

abstract:
  We describe a controllable and precise laser tweezers for Bose-Einstein
condensates of ultracold atomic gases. In our configuration, a laser beam is
used to locally modify the sign of the scattering length in the vicinity of a
trapped BEC. The induced attractive interactions between atoms allow to extract
and transport a controllable number of atoms. We analyze, through numerical
simulations, the number of emitted atoms as a function of the width and
intensity of the outcoupling beam. We also study different configurations of
our system, as the use of moving beams. The main advantage of using the control
laser beam to modify the nonlinear interactions in comparison to the usual way
of inducing optical forces, i.e. through linear trapping potentials, is to
improve the controllability of the outcoupled solitary wave-packet, which opens
new possibilities for engineering macroscopic quantum states.


title:
Correlation Effects in the Triangular Lattice Single-band System
  Li_xNbO_2

abstract:
  Superconductivity in hole-doped Li_xNbO_2 has been reported with T_c ~ 5 K in
the range 0.45 < x < 0.8. The electronic structure is based on a
two-dimensional triangular Nb lattice. The strong trigonal crystal field
results in a single Nb d(z^2) band isolated within a wide gap, leading to a
single-band triangular lattice system. The isolated, partially filled band has
a width W=1.5 eV with dominant second neighbor hopping. To identify possible
correlation effects, we apply DMFT(QMC) using on-site Coulomb repulsion U=0-3
eV, and check selected results using determinant QMC. For U as small as 1 eV,
the single particle spectrum displays a robust lower Hubbard band, suggesting
the importance of correlation effects in Li_xNbO_2 even for U < W. At
half-filling (x=0), a Mott transition occurs at U_c ~ 1.5 eV. Coupling between
the O A_g phonon displacement and correlation effects is assessed.


title:
Multipole expansions for energy and momenta carried by gravitational
  waves

abstract:
  We present expressions for the energy, linear momentum and angular momentum
carried away from an isolated system by gravitational radiation based on
spin-weighted spherical harmonics decomposition of the Weyl scalar $\Psi_4$. We
also show that the expressions derived are equivalent to the common expressions
obtained when using a framework based on perturbations of a Schwazschild
background. The main idea is to collect together all the different expressions
in a uniform and consistent way. The formulae presented here are directly
applicable to the calculation of the radiated energy, linear momentum and
angular momentum starting from the gravitational waveforms which are typically
extracted from numerical simulations.


title:
The intermediate-age globular cluster NGC 1783 in the Large Magellanic
  Cloud

abstract:
  We present Hubble Space Telescope ACS deep photometry of the intermediate-age
globular cluster NGC 1783 in the Large Magellanic Cloud. By using this
photometric dataset, we have determined the degree of ellipticity of the
cluster ($\epsilon$=0.14$\pm$0.03) and the radial density profile. This profile
is well reproduced by a standard King model with an extended core (r_c=24.5'')
and a low concentration (c=1.16), indicating that the cluster has not
experienced the collapse of the core.
  We also derived the cluster age, by using the Pisa Evolutionary Library (PEL)
isochrones, with three different amount of overshooting (namely,
$\Lambda_{os}$=0.0, 0.10 and 0.25). From the comparison of the observed
Color-Magnitude Diagram (CMD) and Main Sequence (MS) Luminosity Function (LF)
with the theoretical isochrones and LFs, we find that only models with the
inclusion of some overshooting ($\Lambda_{os}$=0.10-0.25) are able to reproduce
the observables. By using the magnitude difference $\delta
V_{SGB}^{He-Cl}=0.90$ between the mean level of the He-clump and the flat
region of the SGB, we derive an age $\tau$=1.4$\pm$0.2 Gyr.


title: Communication under Strong Asynchronism

abstract:
  We consider asynchronous communication over point-to-point discrete
memoryless channels. The transmitter starts sending one block codeword at an
instant that is uniformly distributed within a certain time period, which
represents the level of asynchronism. The receiver, by means of a sequential
decoder, must isolate the message without knowing when the codeword
transmission starts but being cognizant of the asynchronism level A. We are
interested in how quickly can the receiver isolate the sent message,
particularly in the regime where A is exponentially larger than the codeword
length N, which we refer to as `strong asynchronism.'
  This model of sparse communication may represent the situation of a sensor
that remains idle most of the time and, only occasionally, transmits
information to a remote base station which needs to quickly take action.
  The first result shows that vanishing error probability can be guaranteed as
N tends to infinity while A grows as Exp(N*k) if and only if k does not exceed
the `synchronization threshold,' a constant that admits a simple closed form
expression, and is at least as large as the capacity of the synchronized
channel. The second result is the characterization of a set of achievable
strictly positive rates in the regime where A is exponential in N, and where
the rate is defined with respect to the expected delay between the time
information starts being emitted until the time the receiver makes a decision.
  As an application of the first result we consider antipodal signaling over a
Gaussian channel and derive a simple necessary condition between A, N, and SNR
for achieving reliable communication.


title: The Informational Conception and Basic Physics

abstract:
  In our previous arXiv papers ("The Information and the Matter", v1, v5; more
systematically the informational conception is presented in the paper "The
Information as Absolute", 2010) it was rigorously shown that Matter in our
Universe - and Universe as a whole - are some informational systems
(structures), which exist as uninterruptedly transforming [practically]
infinitesimal sub-sets of the absolutely infinite and fundamental set
"Information". Such a conception allows not only to clear essentially a number
of metaphysical and epistemological problems in philosophy but, besides, allows
to suggest a reasonable physical model. Since Matter in Universe is an
informational system where any interaction between Matter's sub-structures,
i.e. - particles and systems of the particles - happens always as an exchange
by exclusively true information between these structures, the model is based on
the conjecture that Matter is some analogue of computer. The conjecture, in
turn, allows to introduce in the model the basic logical elements that
constitute the material structures and support the informational exchange -
i.e. the forces - between the structures. The model is experimentally testable
and yet now makes be more clear a number of basic problems in special
relativity, quantum mechanics, and, rather probably, in [now - in Newtonian]
gravity.


title: Higgs Hadroproduction at Large Feynman x

abstract:
  We propose a novel mechanism for the production of the Higgs boson in
inclusive hadronic collisions, which utilizes the presence of heavy quarks in
the proton wave function. In these inclusive reactions the Higgs boson acquires
the momenta of both the heavy quark and antiquark and thus carries 80% or more
of the projectile's momentum. We predict that the cross section ${d \sigma/d
x_F}(p \bar p \to H X)$ for the inclusive production of the Standard Model
Higgs coming from intrinsic bottom Fock states is of order 150 fb at LHC
energies, peaking in the region of $x_F \sim 0.9$. Our estimates indicate that
the corresponding cross section coming from gluon-gluon fusion at $x_F = 0.9$
is relatively negligible and therefore the peak from intrinsic bottom should be
clearly visible for experiments with forward detection capabilities. The
predicted cross section for the production of the Standard Model Higgs coming
from intrinsic heavy quark Fock states in the proton is sufficiently large that
detection at the Tevatron and the LHC may be possible.


title: Difference Equations in Massive Higher Order Calculations

abstract:
  The calculation of massive 2--loop operator matrix elements, required for the
higher order Wilson coefficients for heavy flavor production in deeply
inelastic scattering, leads to new types of multiple infinite sums over
harmonic sums and related functions, which depend on the Mellin parameter $N$.
We report on the solution of these sums through higher order difference
equations using the summation package {\tt Sigma}.


title: Influence of Lorentz-violating terms on a two-level system

abstract:
  The influence of Lorentz- and CPT-violating terms of the extended Standard
Model on a semi-classical two-level system is analyzed. It is shown that the
Lorentz-violating background (when coupled with the fermion sector in a vector
way) is able to induce modifications on the Rabi oscillation pattern, promoting
sensitive modulations on the usual oscillations. As for the term involving the
coefficient coupled in an axial vector way, it brings about oscillations both
on energy states and on the spin states (implied by the background). It is also
seen that such backgrounds are able to yield state oscillations even in the
absence of the electromagnetic field. The foreseen effects are used to
establish upper bounds on the Lorentz-violating coefficients.


title:
Theory of cosmic ray and $\gamma$-ray production in the supernova
  remnant RX J0852.0-4622 (Vela Jr.)

abstract:
  Explicitly time-dependent, nonlinear kinetic theory of cosmic ray (CR)
acceleration in supernova remnants (SNRs) has been used to investigate the
properties of the very large SNR RX J0852.0-4622. The available observations do
not clearly distinguish between a ``nearby'' (at $\sim 200$ pc) and a
``distant'' (at $\sim 1$ kpc) source scenario. Therefore two correspondingly
different models were analyzed. While the 200 pc solution can not be a priory
excluded, the 1 kpc solution turns out to be clearly preferable for physical
reasons. It requires a core collapse supernova (SN) with a massive progenitor
in a molecular cloud $\sim 4000$ yrs ago. The overall synchrotron spectrum and
the filamentary structures in hard X-rays both consistently lead to an
amplified magnetic field $B > 100 \mu$G in the SNR interior. This implies a
suppression of the leptonic TeV $\gamma$-ray emission to about 1 percent of the
flux measured by the H.E.S.S. telescope system which therefore must be
hadronic, consistent with the theoretical solution. Up to the present the 1 kpc
solution has already converted $\sim 10$ percent of the explosion energy into
nonthermal energy, as expected for a Galactic CR source. Also the derived
$\gamma$-ray morphology is consistent with the H.E.S.S. measurements. For the
``nearby'' solution the leptonic and hadronic $\gamma$ ray fluxes are in the
ratio 1:10 which means that this case is also hadronically dominated. However,
the magnetic field strength, consistent with the overall synchrotron spectrum,
differs significantly from that derived from the X-ray filaments. Finally, the
total mechanical energy released amounts to only $1.8 \times 10^{50}$ erg,
uncomfortably low even for a core collapse event.


title:
Preplanetary Nebulae: An HST Imaging Survey and a New Morphological
  Classification System

abstract:
  Using the Hubble Space Telescope (HST), we have carried out a survey of
candidate preplanetary nebulae (PPNs). We report here our discoveries of
objects having well-resolved geometrical structures, and use the large sample
of PPNs now imaged with HST (including previously studied objects in this
class) to devise a comprehensive morphological classification system for this
category of objects. The wide variety of aspherical morphologies which we have
found for PPNs are qualitatively similar to those found for young planetary
nebulae in previous surveys. We also find prominent halos surrounding the
central aspherical shapes in many of our objects -- these are direct signatures
of the undisturbed circumstellar envelopes of the progenitor AGB stars.
Although the majority of these have surface-brightness distributions consistent
with a constant mass-loss rate with a constant expansion velocity, there are
also examples of objects with varying mass-loss rates. As in our surveys of
young planetary nebulae (PNs), we find no round PPNs. The similarities in
morphologies between our survey objects and young PNs supports the view that
the former are the progenitors of aspherical planetary nebulae, and that the
onset of aspherical structure begins during the PPN phase (or earlier). Thus,
the primary shaping of a PN clearly does not occur during the PN phase via the
fast radiative wind of the hot central star, but significantly earlier in its
evolution.


title:
The Properties and Gaseous Environments of Powerful Classical Double
  Radio Galaxies

abstract:
  The properties of a sample of 31 very powerful classical double radio
galaxies with redshifts between zero and 1.8 are studied. The source
velocities, beam powers, ambient gas densities, total lifetimes, and total
outflow energies are presented and discussed. The rate of growth of each side
of each source were obtained using a spectral aging analysis. The beam power
and ambient gas density were obtained by applying the strong shock jump
conditions to the ends of each side of the source. The total outflow lifetime
was obtained by applying the power-law relationship between the beam power and
the total source lifetime derived elsewhere for sources of this type, and the
total outflow energy was obtained by combining the beam power and the total
source lifetime. Composite profiles were constructed by combining results
obtained from each side of each source. The composite profiles indicate that
the ambient gas density falls with distance from the central engine. The source
velocities, beam powers, total lifetimes, and total energies seem to be
independent of radio source size. This is consistent with the standard model in
which each source grows at a roughly constant rate during which time the
central engine puts out a roughly constant beam power. The fact that the total
source lifetimes and energies are independent of radio source size indicates
that the sources are being sampled at random times during their lifetimes.


title: One-way quantum computation with four-dimensional photonic qudits

abstract:
  We consider the possibility of performing linear optical quantum computation
making use of extra photonic degrees of freedom. In particular we focus on the
case where we use photons as quadbits. The basic 2-quadbit cluster state is a
hyper-entangled state across polarization and two spatial mode degrees of
freedom. We examine the non-deterministic methods whereby such states can be
created from single photons and/or Bell pairs, and then give some mechanisms
for performing higher-dimensional fusion gates.


title: Wormholes with a space- and time-dependent equation of state

abstract:
  The discovery that the Universe is undergoing an accelerated expansion has
suggested the existence of an evolving equation of state. This paper discusses
various wormhole solutions in a spherically symmetric spacetime with an
equation of state that is both space and time dependent. The solutions obtained
are exact and generalize earlier results on static wormholes supported by
phantom energy.


title: From the Magnetization Profile to the Stray Field of Bistable Wires

abstract:
  We present new analytical calculations of the spatial dependence of the stray
field of a bistable magnetic wire from the magnetization profile of the wire.
Contributions from the outer shell and from the wire ends are neglected. The
results qualitatively agree with experimental data, taken from literature.


title:
Macroscopic Distinguishability Between Quantum States Defining Different
  Phases of Matter: Fidelity and the Uhlmann Geometric Phase

abstract:
  We study the fidelity approach to quantum phase transitions (QPTs) and apply
it to general thermal phase transitions (PTs). We analyze two particular cases:
the Stoner-Hubbard itinerant electron model of magnetism and the BCS theory of
superconductivity. In both cases we show that the sudden drop of the mixed
state fidelity marks the line of the phase transition. We conduct a detailed
analysis of the general case of systems given by mutually commuting
Hamiltonians, where the non-analyticity of the fidelity is directly related to
the non-analyticity of the relevant response functions (susceptibility and heat
capacity), for the case of symmetry-breaking transitions. Further, on the case
of BCS theory of superconductivity, given by mutually non-commuting
Hamiltonians, we analyze the structure of the system's eigenvectors in the
vicinity of the line of the phase transition showing that their sudden change
is quantified by the emergence of a generically non-trivial Uhlmann mixed state
geometric phase.


title: Atomic lattice excitons: from condensates to crystals

abstract:
  We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed
by fermionic atoms in two bands of an optical lattice. Such a system provides a
clean setup to study fundamental properties of excitons, ranging from
condensation to exciton crystals (which appear for a large effective mass ratio
between particles and holes). Using both mean-field treatments and 1D numerical
computation, we discuss the properities of ALEs under varying conditions, and
discuss in particular their preparation and measurement.


title: Giant magnon bound states from strongly coupled N=4 SYM

abstract:
  We calculate in a very simple way the spectrum of giant magnon bound states
at strong coupling in N=4 SYM, by utilizing the description of the field theory
vacuum in terms of a condensate of eigenvalues of commuting matrices. We
further show that these calculations can be understood in terms of the central
charge extension that permits the calculation of BPS masses in the Coulomb
branch of N=4 SYM. This paper shows further evidence that the strong coupling
expansion of the maximally supersymmetric Yang-Mills theory in four dimensions
can be done systematically from first principles, without the assumption of
integrability.


title: Environmental dependence in the ellipsoidal collapse model

abstract:
  N-body simulations have demonstrated a correlation between the properties of
haloes and their environment. In this paper, we assess whether the ellipsoidal
collapse model can produce a similar dependence. First, we explore the
statistical correlation that originates from Gaussian initial conditions. We
derive analytic expressions for a number of joint statistics of the shear
tensor and estimate the sensitivity of the local characteristics of the shear
to the global geometry of the large scale environment. Next, we concentrate on
the dynamical aspect of the environmental dependence using a simplified model
that takes into account the interaction between a collapsing halo and its
environment. We find that the tidal force exerted by the surrounding mass
distribution causes haloes embedded in overdense regions to virialize earlier.
An effective density threshold whose shape depends on the large scale density
provides a good description of this environmental effect. We show that, using
this approach, a correlation between formation redshift, large scale bias and
environment density naturally arises. The strength of the effect is comparable,
albeit smaller, to that seen in simulations. It is largest for low mass haloes
and decreases as one goes to higher mass objects. Furthermore, haloes that
formed early are substantially more clustered than those that assembled
recently. On the other hand, our analytic model predicts a decrease in median
formation redshift with increasing environment density, in disagreement with
the trend detected in overdense regions. However, our results appear consistent
with the behaviour inferred in relatively underdense regions. We argue that the
ellipsoidal collapse model may apply in low density environments where
nonlinear effects are negligible (abridged).


title: Observational Evidence for Negative-Energy Dust in Late-Times Cosmology

abstract:
  We perform fits of unconventional dark energy models to the available data
from high-redshift supernovae, distant galaxies and baryon oscillations. The
models are based either on brane cosmologies or on Liouville strings in which a
relaxation dark energy is provided by a rolling dilaton field (Q-cosmology). An
interesting feature of such cosmologies is the possibility of effective
four-dimensional negative-energy dust and/or exotic scaling of dark matter. An
important constraint that can discriminate among models is the evolution of the
Hubble parameter as a function of the redshift, H(z). We perform fits using a
unifying formula for the evolution of H(z), applicable to different models. We
find evidence for a negative-energy dust at the current era, as well as for
exotic-scaling (a^{-delta}) contributions to the energy density, with
3.3<delta<4.3. The latter could be due to dark matter coupling with the dilaton
in Q-cosmology models, but it is also compatible with the possibility of dark
radiation from a brane Universe to the bulk in brane-world scenarios, which
could also encompass Q-cosmology models. The best-fit model seems to include an
a^{-2}-scaling contribution to the energy density of the Universe, which is
characteristic of the dilaton relaxation in Q-cosmology models, not to be
confused with the spatial curvature contribution of conventional cosmology. We
conclude that Q-cosmology fits the data equally well with the Lambda-CDM model
for a range of parameters that are in general expected from theoretical
considerations.


title: Effects of non-uniform acceptance in anisotropic flow measurement

abstract:
  Applicability of anisotropic flow measurement techniques and their extension
for detectors with non-uniform azimuthal acceptance are discussed. Considering
anisotropic flow measurement with two and three (mixed harmonic) azimuthal
correlations we introduce a set of observables based on the x and y components
of the event flow vector. These observables provide independent measures of
anisotropic flow, and can be used to test self-consistency of the analysis.
Based on these observables we propose a technique that explicitly takes into
account the effects of non-uniform detector acceptance. Within this approach
the acceptance corrections, as well as parameters which define the method
applicability, can be determined directly from experimental data. For practical
purposes a brief summary of the method is provided at the end.


title: On the space of morphisms between \'etale groupoids

abstract:
  Given two \'etale groupoids $\Cal G$ and $\Cal G'$, we consider the set of
pointed morphisms from $\Cal G$ to $\Cal G'$. Under suitable hypothesis we
introduce on this set a structure of Banach manifold which can be considered as
the space of objects of an \'etale groupoid whose space of orbits is the space
of morphisms from $\Cal G$ to $\Cal G'$.


title: Many-body exchange-correlation effects in graphene

abstract:
  We calculate, within the leading-order dynamical-screening approximation, the
electron self-energy and spectral function at zero temperature for extrinsic
(or gated/doped) graphene. We also calculate hot carrier inelastic scattering
due to electron-electron interactions in graphene. We obtain the inelastic
quasiparticle lifetimes and associated mean free paths from the calculated
self-energy. The linear dispersion and chiral property of graphene gives energy
dependent lifetimes that are qualitatively different from those of
parabolic-band semiconductors.