title: Hilbert modular forms with prescribed ramification

abstract:
  Let $K$ be a totally real field. In this article we present an asymptotic
formula for the number of Hilbert modular cusp forms $f$ with given
ramification at every place $v$ of $K$. When $v$ is an infinite place, this
means specifying the weight of $f$ at $k$, and when $v$ is finite, this means
specifying the restriction to inertia of the local Weil-Deligne representation
attached to $f$ at $v$. Our formula shows that with essentially finitely many
exceptions, the cusp forms of $K$ exhibit every possible sort of ramification
behavior, thus generalizing a theorem of Khare and Prasad. From this fact we
compute the minimal field over which a modular Jacobian becomes semi-stable.


title:
Controllable coherent population transfers in superconducting qubits for
  quantum computing

abstract:
  We propose an approach to coherently transfer populations between selected
quantum states in one- and two-qubit systems by using controllable
Stark-chirped rapid adiabatic passages (SCRAPs). These {\it evolution-time
insensitive} transfers, assisted by easily implementable single-qubit
phase-shift operations, could serve as elementary logic gates for quantum
computing. Specifically, this proposal could be conveniently demonstrated with
existing Josephson phase qubits. Our proposal can find an immediate application
in the readout of these qubits. Indeed, the broken parity symmetries of the
bound states in these artificial "atoms" provide an efficient approach to
design the required adiabatic pulses.

categories: quant-ph cond-mat.mes-hall cond-mat.supr-con cs.GT


title:
Evidence for Resonance Line Scattering in the Suzaku X-ray Spectrum of
  the Cygnus Loop

abstract:
  We present an analysis of the Suzaku observation of the northeastern rim of
the Cygnus Loop supernova remnant. The high detection efficiency together with
the high spectral resolution of the Suzaku X-ray CCD camera enables us to
detect highly-ionized C and N emission lines from the Cygnus Loop. Given the
significant plasma structure within the Suzaku field of view, we selected the
softest region based on ROSAT observations. The Suzaku spectral data are well
characterized by a two-component non-equilibrium ionization model with
different best-fit values for both the electron temperature and ionization
timescale. Abundances of C to Fe are all depleted to typically 0.23 times solar
with the exception of O. The abundance of O is relatively depleted by an
additional factor of two compared with other heavy elements. We found that the
resonance-line-scattering optical depth for the intense resonance lines of O is
significant and, whereas the optical depth for other resonance lines is not as
significant, it still needs to be taken into account for accurate abundance
determination.


title: Spin-Hall effects in a Josephson contact

abstract:
  The Josephson tunneling through a 2D normal contact with the spin-orbit split
conduction band has been studied in the diffusive regime. Linearized Usadel
equations for triplet components of the pairing function revealed a striking
similarity to the equations of spin diffusion driven by the electric field in
normal metals. Consequently, we predict that the out-of-plane spin-Hall
polarization accumulates towards lateral sample edges and the in-plane
polarization is finite throughout the entire normal region. At the same time,
the spin-Hall current is absent in the considered case of the stationary
Josephson effect.


title: Constraints on Deflation from the Equation of State of Dark Energy

abstract:
  In cyclic cosmology based on phantom dark energy the requirement that our
universe satisfy a CBE-condition ({\it Comes Back Empty}) imposes a lower bound
on the number $N_{\rm cp}$ of causal patches which separate just prior to
turnaround. This bound depends on the dark energy equation of state $w = p/\rho
= -1 - \phi$ with $\phi > 0$. More accurate measurement of $\phi$ will
constrain $N_{\rm cp}$. The critical density $\rho_c$ in the model has a lower
bound $\rho_c \ge (10^9 {\rm GeV})^4$ or $\rho_c \ge (10^{18} {\rm GeV})^4$
when the smallest bound state has size $10^{-15}$m, or $10^{-35}$m,
respectively.


title: Shear viscosity of boost invariant plasma at finite coupling

abstract:
  We discuss string theory alpha' corrections in the dual description of the
expanding boost invariant N=4 supersymmetric Yang-Mills plasma at strong
coupling. We compute finite 't Hooft coupling corrections to the shear
viscosity and find that it disagrees with the equilibrium correlation function
computations. We comment on the possible source of the discrepancy.


title:
The distribution of natural numbers divisible by 2,3,5,11,13 and 17 on
  the Square Root Spiral

abstract:
  The natural numbers divisible by the Prime Factors 2, 3, 5, 11, 13 and 17 lie
on defined spiral graphs, which run through the Square Root Spiral. A
mathematical analysis shows, that these spiral graphs are defined by specific
quadratic polynomials. Basically all natural number which are divisible by the
same prime factor lie on such spiral graphs. And these spiral graphs can be
assigned to a certain number of Spiral Graph Systems, which have a defined
spatial orientation to each other. This document represents a supplementation
to my detailed introduction study to the Square Root Spiral, and it contains
the missing diagrams and analyses, showing the distribution of the natural
numbers divisible by 2, 3, 5, 11, 13 and 17 on the Square Root Spiral. My
introduction study to the Square Root Spiral can be found in the arxiv-archive.
The title of this study : The ordered distribution of the natural numbers on
the Square Root Spiral.


title:
It's Not What You Have, But How You Use It: Compromises in Mobile Device
  Use

abstract:
  As users begin to use many more devices for personal information management
(PIM) than just the traditional desktop computer, it is essential for HCI
researchers to understand how these devices are being used in the wild and
their roles in users' information environments. We conducted a study of 220
knowledge workers about their devices, the activities they performed on each,
and the groups of devices used together. Our findings indicate that several
devices are often used in groups; integrated multi-function portable devices
have begun to replace single-function devices for communication (e.g. email and
IM). Users use certain features opportunistically because they happen to be
carrying a multi-function device with them. The use of multiple devices and
multi-function devices is fraught with compromises as users must choose and
make trade-offs among various factors.


title: Follow-up observations of binary ultra-cool dwarfs

abstract:
  Astrometric observations of resolved binaries provide estimates of orbital
periods and will eventually lead to measurement of dynamical masses. Only a few
very low mass star and brown dwarf masses have been measured to date, and the
mass-luminosity relation still needs to be calibrated.
  We have monitored 14 very low mass multiple systems for several years to
confirm their multiplicity and, for those with a short period, derive accurate
orbital parameters and dynamical mass estimates.
  We have used high spatial resolution images obtained at the Paranal, Lick and
HST observatories to obtain astrometric and photometric measurements of the
multiple systems at several epochs. The targets have periods ranging from 5 to
200 years, and spectral types in the range M7.5 - T5.5.
  All of our 14 multiple systems are confirmed as common proper motion pairs.
One system (2MASSW J0920122+351742) is not resolved in our new images, probably
because the discovery images were taken near maximum elongation. Six systems
have periods short enough to allow dynamical mass measurements within the next
15 to 20years. We estimate that only 8% of the ultracool dwarfs in the solar
neighborhood are binaries with separations large enough to be resolved, and yet
periods short enough to derive astrometric orbital fits over a reasonable time
frame with current instrumentation. A survey that doubles the number of
ultracool dwarfs observed with high angular resolution is called for to
discover enough binaries for a first attempt to derive the mass-luminosity
relationship for very low-mass stars and brown dwarfs.


title: Invariant manifolds for a singular ordinary differential equation

abstract:
  We study the singular ordinary differential equation
  $$
  \frac{d U}{d t} = f (U) / z (U) + g (U),
  $$ where $U \in R^N$, the functions $f \in R^N $ and $g \in R^N $ are of
class $C^2$ and $z $ is a real valued $C^2$ function. The equation is singular
in the sense that $z (U)$ can attain the value 0. We focus on the solutions of
the singular ODE that belong to a small neighborhood of a point $\bar U$ such
that $f (\bar U) = g (\bar U) = \vec 0$, $z (\bar U) =0$. We investigate the
existence of manifolds that are locally invariant for the singular ODE and that
contain orbits with a suitable prescribed asymptotic behaviour. Under suitable
hypotheses on the set $\{U: z (U) = 0 \}$, we extend to the case of the
singular ODE the definitions of center manifold, center stable manifold and of
uniformly stable manifold. An application of our analysis concerns the study of
the viscous profiles with small total variation for a class of mixed
hyperbolic-parabolic systems in one space variable. Such a class includes the
compressible Navier Stokes equation.


title:
A theoretical and semiemprical correction to the long-range dispersion
  power law of stretched graphite

abstract:
  In recent years intercalated and pillared graphitic systems have come under
increasing scrutiny because of their potential for modern energy technologies.
While traditional \emph{ab initio} methods such as the LDA give accurate
geometries for graphite they are poorer at predicting physicial properties such
as cohesive energies and elastic constants perpendicular to the layers because
of the strong dependence on long-range dispersion forces. `Stretching' the
layers via pillars or intercalation further highlights these weaknesses. We use
the ideas developed by [J. F. Dobson et al, Phys. Rev. Lett. {\bf 96}, 073201
(2006)] as a starting point to show that the asymptotic $C_3 D^{-3}$ dependence
of the cohesive energy on layer spacing $D$ in bigraphene is universal to all
graphitic systems with evenly spaced layers. At spacings appropriate to
intercalates, this differs from and begins to dominate the $C_4 D^{-4}$ power
law for dispersion that has been widely used previously. The corrected power
law (and a calculated $C_3$ coefficient) is then unsuccesfully employed in the
semiempirical approach of [M. Hasegawa and K. Nishidate, Phys. Rev. B {\bf 70},
205431 (2004)] (HN). A modified, physicially motivated semiempirical method
including some $C_4 D^{-4}$ effects allows the HN method to be used
successfully and gives an absolute increase of about $2-3%$ to the predicted
cohesive energy, while still maintaining the correct $C_3 D^{-3}$ asymptotics.


title:
On the physics behind the form factor ratio $\mu_p G_E^p (Q^2) / G_M^p
  (Q^2)$

abstract:
  We point out that there exist two natural definitions of the nucleon
magnetization densities : the density $\rho_M^K (r)$ introduced in Kelly's
phenomenological analysis and theoretically more standard one $\rho_M (r)$. We
can derive an explicit analytical relation between them, although Kelly's
density is more useful to disentangle the physical origin of the different
$Q^2$ dependence of the Sachs electric and magnetic form factors of the
nucleon. We evaluate both of $\rho_M (r)$ and $\rho_M^K (r)$ as well as the
charge density $\rho_{ch}(r)$ of the proton within the framework of the chiral
quark soliton model, to find a noticeable qualitative difference between
$\rho_{ch}(r)$ and $\rho_M^K (r)$, which is just consistent with Kelly's result
obtained from the empirical information on the Sachs electric and magnetic form
factors of the proton.


title:
A Langevin Approach to One-Dimensional Granular Media Fluidized by
  Vibrations

abstract:
  We present a Langevin approach to describe the steady-state dynamics of
one-dimensional granular media fluidized by a vibrating bottom plate. We adopt
a linear Langevin equation to describe the motion of the center of mass. Within
this framework, we derive analytical expressions for several macroscopic
quantities. We also predict the power spectrum for the height of the center of
mass. We find good agreement between our theoretical predictions and extensive
event-driven molecular dynamics simulations.


title:
$L^2$-torsion invariants and the Magnus representation of the mapping
  class group

abstract:
  In this paper, we study a series of $L^2$-torsion invariants from the
viewpoint of the mapping class group of a surface. We establish some vanishing
theorems for them. Moreover we explicitly calculate the first two invariants
and compare them with hyperbolic volumes.


title:
Magnetically induced spin-dependent photoemission from p-GaAs(Cs,O) into
  vacuum

abstract:
  A spin-dependent emission of optically oriented electrons from p-GaAs(Cs,O)
into vacuum was experimentally observed in a magnetic field normal to the
surface. This phenomenon is explained within the model which takes into account
the jump in the electron g factor at the semiconductor-vacuum interface. Due to
this jump, the effective electron affinity on the semiconductor surface depends
on the mutual direction of optically oriented electron spins and the magnetic
field, resulting in the spin-dependent photoemission. It is demonstrated that
the observed effect can be used for the determination of spin diffusion length
in semiconductors.


title:
Phase space patterns of quantum transport on ordered and disordered
  networks

abstract:
  In this paper, we consider the quantum-mechanical phase space patterns on
ordered and disordered networks. For ordered networks in which each node is
connected to its 2m nearest neighbors (m on either side), the phase space
quasi-probability of Wigner function shows various patterns. In the long time
limit, on even-numbered networks, we find an asymmetric quasi-probability
between the node and its opposite node. This asymmetry depends on the network
parameters and specific phase space positions. For disordered networks in which
each edge is rewired with probability p>0, the phase space displays regional
localization on the initial node.


title: A bijective proof for a theorem of Ehrhart

abstract:
  We give a new proof for a theorem of Ehrhart regarding the
quasi-polynomiality of the function that counts the number of integer points in
the integral dilates of a rational polytope. The proof involves a geometric
bijection, inclusion-exclusion, and recurrence relations, and we also prove
Ehrhart reciprocity using these methods.


title:
Static dielectric response of icosahedral fullerenes from C60 to C2160
  by an all electron density functional theory

abstract:
  The static dielectric response of C60, C180, C240, C540, C720, C960, C1500,
and C2160 fullerenes is characterized by an all-electron density-functional
method. First, the screened polarizabilities of C60, C180, C240, and C540, are
determined by the finite-field method using Gaussian basis set containing 35
basis functions per atom. In the second set of calculations, the unscreened
polarizabilities are calculated for fullerenes C60 through C2160 from the
self-consistent Kohn-Sham orbitals and eigen-values using the sum-over-states
method. The approximate screened polarizabilities, obtained by applying a
correction determined within linear response theory show excellent agreement
with the finite-field polarizabilities. The static dipole polarizability per
atom in C2160 is (4 Angstrom^3) three times larger than that in C60 (1.344
Angstrom^3). Our results reduce the uncertainty in various theoretical models
used previously to describe the dielectric response of fullerenes and show that
quantum size effects in polarizability are significantly smaller than
previously thought.


title:
Interplay among the azimuthally dependent HBT radii and the elliptic
  flow

abstract:
  We present a calculation of the elliptic flow and azimuthal dependence of the
correlation radii in the ellipsoidally symmetric generalization of the
Buda-Lund model. The elliptic flow is shown to depend only on the flow
anisotropy while in case of correlation radii both flow and space anisotropy
play an important role in determining their azimuthal oscillation. We also
outline a simple procedure for determining the parameters of the model from
data.


title:
How much can donor/acceptor-substitution change the responses of long
  push-pull systems to DC fields?

abstract:
  Mathematical arguments are presented that give a unique answer to the
question in the title. Subsequently, the mathematical analysis is extended
using results of detailed model calculations that, in addition, throw further
light on the consequences of the analysis. Finally, through a comparison with
various recent studies, many of the latter are given a new interpretation.


title:
Modulations to molecular high order harmonic generation by electron de
  Broglie wave

abstract:
  We present a new theory that the molecular high order harmonic generation in
an intense laser field is determined by molecular internal symmetry and
momentum distribution of the tunneling-ionized electron. The molecular internal
symmetry determines the quantum interference form of the returning electron
inside the molecule. The electron momentum distribution determines the relative
interference strength of each individual electron de Broglie wave. All
individual electron de Broglie wave interferences add together to collectively
modulate the molecular high harmonic generation. We specifically discuss the
suppression of the generation on adjacent harmonic orders and the dependence of
molecular high harmonic generation on laser intensities and molecular axis
alignment. Our theoretical results are in good consistency with the
experimental observations.


title:
Self-Adjoint Extensions of the Hamiltonian Operator with Symmetric
  Potentials which are Unbounded from Below

abstract:
  We study the self-adjoint extensions of the Hamiltonian operator with
symmetric potentials which go to $-\infty$ faster than $-|x|^{2p}$ with $p>1$
as $x\to\pm\infty$. In this extension procedure, one requires the Wronskian
between any states in the spectrum to approach to the same limit as
$x\to\pm\infty$. Then the boundary terms cancel and the Hamiltonian operator
can be shown to be hermitian. Discrete bound states with even and odd parities
are obtained. Since the Wronskian is not required to vanish asymptotically, the
energy eigenstates could be degenerate. Some explicit examples are given and
analyzed.


title: PILOT: design and capabilities

abstract:
  The proposed design for PILOT is a general-purpose, wide-field 1 degree 2.4m,
f/10 Ritchey-Chretien telescope, with fast tip-tilt guiding, for use 0.5-25
microns. The design allows both wide-field and diffraction-limited use at these
wavelengths. The expected overall image quality, including median seeing, is
0.28-0.3" FWHM from 0.8-2.4 microns. Point source sensitivities are estimated.


title:
An Algorithm for Finding Symmetric Gr\"obner Bases in Infinite
  Dimensional Rings

abstract:
  A \textit{symmetric ideal} $I \subseteq R = K[x_1,x_2,...]$ is an ideal that
is invariant under the natural action of the infinite symmetric group. We give
an explicit algorithm to find Gr\"obner bases for symmetric ideals in the
infinite dimensional polynomial ring $R$. This allows for symbolic computation
in a new class of rings. In particular, we solve the ideal membership problem
for symmetric ideals of $R$.


title: PILOT and cosmic shear

abstract:
  Cosmic shear offers a remarkbly clean way to measure the equation of state of
the Universe and its evolution. Resolution over a wide field is paramount, and
Antarctica offers unique possibilities in this respect. There is an order of
magnitude gain in speed over temperate sites, or a factor three in surface
density. This means that PILOT outperforms much larger telescopes elsewhere,
and can compete with the proposed DUNE space mission.
  Keywords: Antarctic astronomy, Surveys, Adaptive optics, Weak lensing


title:
Detection of HCO2+ toward the Low-Mass Protostar IRAS 04368+2557 in
  L1527

abstract:
  The millimeter-wave rotational emission lines (4(04)-3(03) and 5(05)-4(04))
of protonated carbon dioxide, HCO2+(HOCO+), has been detected toward the
low-mass class 0 protostar IRAS 04368+2557 in L1527 with the IRAM 30 m
telescope. This is the first detection of HCO2+ except for the Galactic Center
clouds. The column density of HCO2+ averaged over the beam size (29") is
determined to be 7.6x10^10 cm^-2, assuming the rotational temperature of 12.3
K. The fractional abundance of gaseous CO2 relative to H2 is estimated from the
column density of HCO2+ with an aid of a simplified chemical model. If the
HCO2+ emission only comes from the evaporation region of CO2 near the protostar
(T>50 K), the fractional abundance of CO2 is estimated to be higher than
6.6x10^-4. This is comparable to the elemental abundance of carbon in
interstellar clouds, and hence, the direct evaporation of CO2 from dust grain
is unrealistic as a source of gaseous CO2 in L1527. A narrow line width of
HCO2+ also supports this. On the other hand, the fractional abundance of CO2 is
estimated to be 2.9x10^-7, if the source size is comparable to the beam size.
These results indicate that gaseous CO2 is abundant even in the low-mass
star-forming region. Possible production mechanisms of gaseous CO2 are
discussed.


title: The Synthesis of Regression Slopes in Meta-Analysis

abstract:
  Research on methods of meta-analysis (the synthesis of related study results)
has dealt with many simple study indices, but less attention has been paid to
the issue of summarizing regression slopes. In part this is because of the many
complications that arise when real sets of regression models are accumulated.
We outline the complexities involved in synthesizing slopes, describe existing
methods of analysis and present a multivariate generalized least squares
approach to the synthesis of regression slopes.


title: Conjugacy Classes of 3-Braid Group B_3

abstract:
  In this article we describe the summit sets in B_3, the smallest element in a
summit set and we compute the Hilbert series corresponding to conjugacy
classes.The results will be related to Birman-Menesco classification of knots
with braid index three or less than three.


title:
Temperature Dependence of the Spin Resistivity in Ferromagnetic Thin
  Films

abstract:
  The magnetic phase transition is experimentally known to give rise to an
anomalous temperature-dependence of the electron resistivity in ferromagnetic
crystals. Phenomenological theories based on the interaction between itinerant
electron spins and lattice spins have been suggested to explain these
observations. In this paper, we show by extensive Monte Carlo (MC) simulation
the behavior of the resistivity of the spin current calculated as a function of
temperature ($T$) from low-$T$ ordered phase to high-$T$ paramagnetic phase in
a ferromagnetic film. We analyze in particular effects of film thickness,
surface interactions and different kinds of impurities on the spin resistivity
across the critical region. The origin of the resistivity peak near the phase
transition is shown to stem from the existence of magnetic domains in the
critical region. We also formulate in this paper a theory based on the
Boltzmann's equation in the relaxation-time approximation. This equation can be
solved using numerical data obtained by our simulations. We show that our
theory is in a good agreement with our MC results. Comparison with experiments
is discussed.


title: Comparative study of ordered and disordered Y1-xSrxCoO3-d

abstract:
  We have succeeded in preparing A-site ordered- and disordered-Y1/4Sr3/4CoO3-d
with various oxygen deficiencies delta, and have made comparative study of
their structural and physical properties. In the A-site ordered structure,
oxygen vacancies order, and d = 0.34 sample shows a weak ferromagnetic
transition beyond 300 K. On the other hand, in the A-site disordered structure,
no oxygen vacancy ordering is observed, and d = 0.16 sample shows a
ferromagnetic metallic transition around 150 K. A-site disordering destroys the
orderings of oxygen-vacancies and orbitals, leading to the strong modification
of the electronic phases.


title: Detection of solar-like oscillations in the G5 subgiant mu-Herculis

abstract:
  A clear detection of excess of power, providing a substantial evidence for
solar-like oscillations in the G5 subgiant \muher{}, is presented. This star
was observed over seven nights with the SARG echelle spectrograph operating
with the 3.6-m Italian TNG Telescope, using an iodine absorption cell as a
velocity reference. A clear excess of power centered at 1.2 mHz, with peak
amplitudes of about 0.9 \ms in the amplitude spectrum is present. Fitting the
asymptotic relation to the power spectrum, a mode identification for the
$\ell=0,1,2,3$ modes in the frequency range $900-1600 \muHz$ is derived. The
most likely value for the large separation turns out to be 56.5 \muHz,
consistent with theoretical expectations. The mean amplitude per mode ($l=0,1$)
at peak power results to be $0.63 \rm m s^{-1}$, almost three times larger than
the solar one.


title: Diffusion limited cluster aggregation with irreversible flexible bonds

abstract:
  Irreversible diffusion limited cluster aggregation (DLCA) of hard spheres was
simulated using Brownian cluster dynamics. Bound spheres were allowed to move
freely within a specified range, but no bond breaking was allowed. The
structure and size distribution of the clusters was investigated before
gelation. The pair correlation function and the static structure factor of the
gels were determined as a function of the volume fraction and time. Bond
flexibility led to local densification of the clusters and the gels, with a
certain degree of order. At low volume fractions densification of the clusters
occurred during their growth, but at higher volume fractions it occurred mainly
after gelation. At very low volume fractions, the large scale structure
(fractal dimension), size distribution and growth kinetics of the clusters was
found to be close to that known for DLCA with rigid bonds. Restructuring of the
gels continued for long times, indicating that aging processes in systems with
strong attraction do not necessarily involve bond breaking. The mean square
displacement of particles in the gels was determined. It is shown to be highly
heterogeneous and to increase with decreasing volume fraction.


title:
Physical Properties of Wave Motion in Inclined Magnetic Fields Within
  Sunspot Penumbrae

abstract:
  At the surface of the Sun, acoustic waves appear to be affected by the
presence of strong magnetic fields in active regions. We explore the
possibility that the inclined magnetic field in sunspot penumbrae may convert
primarily vertically propagating acoustic waves into elliptical motion. We use
helioseismic holography to measure the modulus and phase of the correlation
between incoming acoustic waves and the local surface motion within two
sunspots. These correlations are modeled assuming the surface motion is
elliptical, and we explore the properties of the elliptical motion on the
magnetic field inclination. We also demonstrate that the phase shift of the
outward propagating waves is opposite to the phase shift of the inward
propagating waves in stronger, more vertical fields, but similar to the inward
phase shifts in weaker, more inclined fields.


title: Gravitation model for spatial network based on the heterogeneous node

abstract:
  In this paper we consider nodes in network are heterogeneous and the link
between nodes is caused by the potential dynamical demand of the nodes. Such
demand can be measured by gravitation which increases with the heterogeneous
strength of node and decreases with the geographical distance. Based on this,
we propose a new model for spatial network from the view of gravitation. The
model is to maximize the potential dynamical demand of the whole network,
indicating the possible maximal efficiency of the network and the highest
profits that operators may gain. The model can vary its topology by changing
two parameters. A simulation for the Chinese city airline network is completed.
In the end of this article we discuss the significance and advantage of the
heterogeneous nodes.


title:
Effect of electric field on the photoluminescence of polymer-inorganic
  nanoparticles composites

abstract:
  We report on the effect of electric field on the photoluminescence, PL, from
a composite consisting of a conjugated polymer mixed with zinc oxide
nanoparticles. We have found that in the absence of electric field PL emission
from the composite film has two maxima in the blue and green-yellow regions.
Application of a voltage bias to planar gold electrodes suppresses the
green-yellow emission and shifts the only PL emission maximum towards the blue
region. Current-voltage characteristics of the polymer-nanoparticles composite
exhibit the non-linear behavior typical of non-homogeneous polymer-inorganic
structures. Generation of excited states in the composite structure implies the
presence of several radiative recombination mechanisms including formation of
polymer-nanoparticle complexes including exciplex states and charge transfer
between the polymer and nanoparticle that can be controlled by an electric
field.


title: Antisymmetric Elements in Group Rings II

abstract:
  Let $R$ be a commutative ring, $G$ a group and $RG$ its group ring. Let $\vp
: RG\to RG$ denote the $R$-linear extension of an involution $\vp$ defined on
$G$. An element $x$ in $RG$ is said to be $\vp$-antisymmetric if $\vp (x) =
-x$. A characterization is given of when the $\vp$-antisymmetric elements of
$RG$ commute. This is a completion of earlier work.


title:
Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30m
  telescope - (1985 -- 2005)

abstract:
  The planets Uranus and Neptune with small apparent diameters are primary
calibration standards. We investigate their variability at ~90 GHz using
archived data taken at the IRAM 30m telescope during the 20 years period 1985
to 2005. We calibrate the planetary observations against non-variable secondary
standards (NGC7027, NGC7538, W3OH, K3-50A) observed almost simultaneously.
Between 1985 and 2005, the viewing angle of Uranus changed from south-pole to
equatorial. We find that the disk brightness temperature declines by almost 10%
(~2sigma) over this time span indicating that the south-pole region is
significantly brighter than average. Our finding is consistent with recent
long-term radio observations at 8.6 GHz by Klein & Hofstadter (2006). Both data
sets do moreover show a rapid decrease of the Uranus brightness temperature
during the year 1993, indicating a temporal, planetary scale change. We do not
find indications for a variation of Neptune's brightness temperature at the 8%
level. If Uranus is to be used as calibration source, and if accuracies better
than 10% are required, the Uranus sub-earth point latitude needs to be taken
into account.


title: On the Correlation between Spin Parameter and Halo Mass

abstract:
  We report on a correlation between virial mass M and spin parameter lambda
for dark matter halos forming at redshifts z > 10. We find that the spin
parameter decreases with increasing halo mass. Interestingly, our analysis
indicates that halos forming at later times do not exhibit such a strong
correlation, in agreement with the findings of previous studies. We briefly
discuss the implications of this correlation for galaxy formation at high
redshifts and the galaxy population we observe today.


title:
Ground-state reference systems for expanding correlated fermions in one
  dimension

abstract:
  We study the sudden expansion of strongly correlated fermions in a
one-dimensional lattice, utilizing the time-dependent density-matrix
renormalization group method. Our focus is on the behavior of experimental
observables such as the density, the momentum distribution function, and the
density and spin structure factors. As our main result, we show that
correlations in the transient regime can be accurately described by equilibrium
reference systems. In addition, we find that the expansion from a Mott
insulator produces distinctive peaks in the momentum distribution function at
|k| ~ pi/2, accompanied by the onset of power-law correlations.


title: The generation and stability of magnetic fields in CP stars

abstract:
  A variety of magnetohydrodynamic mechanisms that may play a role in magnetic,
chemically peculiar (mCP) stars is reviewed. These involve dynamo mechanisms in
laminar flows as well as turbulent environments, and magnetic instabilities of
poloidal and toroidal fields as well as combinations of the two. While the
proto-stellar phase makes the survival of primordial fields difficult, the
variety of magnetic field configurations on mCP stars may be an indication for
that they are instability remnants, but there is no process which is clearly
superior in explaining the strong fields.


title:
LMC origin of the hyper-velocity star HE 0437-5439. Beyond the
  supermassive black hole paradigm

abstract:
  Context: Hyper-velocity stars move so fast that only a supermassive black
hole (SMBH) seems to be capable to accelerate them. Hence the Galactic centre
(GC) is their only suggested place of origin. Edelmann et al. (2005) found the
early B-star HE0437-5439 to be too short-lived to have reached its current
position in the Galactic halo if ejected from the GC, except if being a blue
straggler. Its proximity to the LMC suggested an origin from this galaxy. Aims:
The chemical signatures of stars at the GC are significantly different from
those in the LMC. Hence, an accurate measurement of the abundance pattern of
HE0437-5439 will yield a new tight constraint on the place of birth of this
star. Methods: High-resolution spectra obtained with UVES on the VLT are
analysed using state-of-the-art non-LTE modelling techniques. Results: We
measured abundances of individual elements to very high accuracy in HE0437-5439
as well as in two reference stars, from the LMC and the solar neighbourhood.
The abundance pattern is not consistent at all with that observed in stars near
the GC, ruling our an origin from the GC. However, there is a high degree of
consistency with the LMC abundance pattern. Our abundance results cannot rule
out an origin in the outskirts of the Galactic disk. However, we find the life
time of HE0437-5439 to be more than 3 times shorter than the time of flight to
the edge of the disk, rendering a Galactic origin unlikely. Conclusions: Only
one SMBH is known to be present in Galaxy and none in the LMC. Hence the
exclusion of an GC origin challenges the SMBH paradigm. We conclude that there
must be other mechanism(s) to accelerate stars to hyper-velocity speed than the
SMBH. We draw attention to dynamical ejection from dense massive clusters, that
has recently been proposed by Gvaramadze et al. (2008).


title:
Nearing Extremal Intersecting Giants and New Decoupled Sectors in N = 4
  SYM

abstract:
  We study near-horizon limits of near-extremal charged black hole solutions to
five-dimensional $U(1)^3$ gauged supergravity carrying two charges, extending
the recent work of Balasubramanian et.al. We show that there are two
near-horizon decoupling limits for the near-extremal black holes, one
corresponding to the near-BPS case and the other for the far from BPS case.
Both of these limits are only defined on the 10d IIB uplift of the 5d black
holes, resulting in a decoupled geometry with a six-dimensional part (conformal
to) a rotating BTZ X $S^3$. We study various aspects of these decoupling limits
both from the gravity side and the dual field theory side. For the latter we
argue that there should be two different, but equivalent, dual gauge theory
descriptions, one in terms of the 2d CFT's dual to the rotating BTZ and the
other as certain large R-charge sectors of d=4,N =4 U(N) SYM theory. We discuss
new BMN-type sectors of the N=4 SYM in the $N\to\infty$ limit in which the
engineering dimensions scale as $N^{3/2}$ (for the near-BPS case) and as $N^2$
(for the far from BPS case).


title:
Analytic Perturbation Theory and Renormalization Analysis of Matter
  Coupled to Quantized Radiation

abstract:
  For a large class of quantum mechanical models of matter and radiation we
develop an analytic perturbation theory for non-degenerate ground states. This
theory is applicable, for example, to models of matter with static nuclei and
non-relativistic electrons that are coupled to the UV-cutoff quantized
radiation field in the dipole approximation. If the lowest point of the energy
spectrum is a non-degenerate eigenvalue of the Hamiltonian, we show that this
eigenvalue is an analytic function of the nuclear coordinates and of
$\alpha^{3/2}$, $\alpha$ being the fine structure constant. A suitably chosen
ground state vector depends analytically on $\alpha^{3/2}$ and it is twice
continuously differentiable with respect to the nuclear coordinates.


title: Integral Points on Hyperelliptic Curves

abstract:
  We give a completely explicit upper bound for integral points on (standard)
affine models of hyperelliptic curves, provided we know at least one rational
point and a Mordell-Weil basis of the Jacobian. We also explain a powerful
refinement of the Mordell--Weil sieve which, combined with the upper bound, is
capable of determining all the integral points. Our method is illustrated by
determining the integral points on a two genus 2 hyperelliptic curves with
Mordell--Weil Jacobian ranks of 3 and 6.


title:
Spectral gaps for periodic Schr\"odinger operators with hypersurface
  magnetic wells

abstract:
  We consider a periodic magnetic Schr\"odinger operator on a noncompact
Riemannian manifold $M$ such that $H^1(M, \RR)=0$ endowed with a properly
discontinuous cocompact isometric action of a discrete group. We assume that
there is no electric field and that the magnetic field has a periodic set of
compact magnetic wells. We review a general scheme of a proof of existence of
an arbitrary large number of gaps in the spectrum of such an operator in the
semiclassical limit, which was suggested in our previous paper, and some
applications of this scheme. Then we apply these methods to establish similar
results in the case when the wells have regular hypersurface pieces.


title: Dynamics of Neural Networks with Continuous Attractors

abstract:
  We investigate the dynamics of continuous attractor neural networks (CANNs).
Due to the translational invariance of their neuronal interactions, CANNs can
hold a continuous family of stationary states. We systematically explore how
their neutral stability facilitates the tracking performance of a CANN, which
is believed to have wide applications in brain functions. We develop a
perturbative approach that utilizes the dominant movement of the network
stationary states in the state space. We quantify the distortions of the bump
shape during tracking, and study their effects on the tracking performance.
Results are obtained on the maximum speed for a moving stimulus to be
trackable, and the reaction time to catch up an abrupt change in stimulus.


title: Improving Swift-XRT positions of GRBs

abstract:
  Since GRBs fade rapidly, it is important to publish accurate, precise
positions at early times. For Swift-detected bursts, the best promptly
available position is most commonly the X-ray Telescope (XRT) position. We
present two processes, developed by the Swift team at Leicester, which are now
routinely used to improve the precision and accuracy of the XRT positions
reported by the Swift team. Both methods, which are fully automated, make use
of a PSF-fitting approach which accounts for the bad columns on the CCD. The
first method yields positions with 90% error radii <4.4" 90% of the time,
within 10--20 minutes of the trigger. The second method astrometrically
corrects the position using UVOT field stars and the known mapping between the
XRT and UVOT detectors, yielding enhanced positions with 90% error radii of
<2.8" 90% of the time, usually ~2 hours after the trigger.


title:
A new derivation of Luscher F-term and fluctuations around the giant
  magnon

abstract:
  In this paper we give a new derivation of the generalized Luscher F-term
formula from a summation over quadratic fluctuations around a given soliton.
The result is very general providing that S-matrix is diagonal and is valid for
arbitrary dispersion relation. We then apply this formalism to compute the
leading finite size corrections to the giant magnon dispersion relation coming
from quantum fluctuations.


title: A microscopic view on contact angle selection

abstract:
  We discuss the equilibrium condition for a liquid that partially wets a solid
on the level of intermolecular forces. Using a mean field continuum
description, we generalize the capillary pressure from variation of the free
energy and show at what length scale the equilibrium contact angle is selected.
After recovering Young's law for homogeneous substrates, it is shown how
hysteresis of the contact angle can be incorporated in a self-consistent
fashion. In all cases the liquid-vapor interface takes a nontrivial shape,
which is compared to models using a disjoining pressure.


title: AGB Variables and the Mira Period-Luminosity Relation

abstract:
  Published data for large amplitude asymptotic giant branch variables in the
Large Magellanic Cloud are re-analysed to establish the constants for an
infrared (K) period-luminosity relation of the form: Mk=rho[log P-2.38] +
delta. A slope of rho=-3.51+/-0.20 and a zero point of delta=-7.15+/-0.06 are
found for oxygen-rich Miras (if a distance modulus of 18.39+/-0.05 is used for
the LMC). Assuming this slope is applicable to Galactic Miras we discuss the
zero-point for these stars using the revised Hipparcos parallaxes together with
published VLBI parallaxes for OH Masers and Miras in Globular Clusters. These
result in a mean zero-point of delta=-7.25+/-0.07 for O-rich Galactic Miras.
The zero-point for Miras in the Galactic Bulge is not significantly different
from this value.
  Carbon-rich stars are also discussed and provide results that are consistent
with the above numbers, but with higher uncertainties. Within the uncertainties
there is no evidence for a significant difference between the period-luminosity
relation zero-points for systems with different metallicity.


title: 2PI nonequilibrium versus transport equations for an ultracold Bose gas

abstract:
  The far-from-equilibrium dynamics of an ultracold, one-dimensional Bose gas
is studied. The focus is set on the comparison between the solutions of fully
dynamical evolution equations derived from the 2PI effective action and their
corresponding kinetic approximation in the form of Boltzmann-type transport
equations. It is shown that during the time evolution of the gas a kinetic
description which includes non-Markovian memory effects in a gradient expansion
becomes valid. The time scale at which this occurs is shown to exceed
significantly the time scale at which the system's evolution enters a
near-equilibrium drift period where a fluctuation dissipation relation is found
to hold and which would seem to be predestined for the kinetic approximation.


title: Isospin effects in the thermodynamics of finite nuclei

abstract:
  It has been proposed that multifragmentation can be related to the liquid-gas
phase transition of nuclear matter. We study the statistical properties of
finite nuclear matter near the phase transition with the help of a Lattice Gas
Model (LGM). The original version of LGM with only one type of charge-neutral
particles is well known to feature the properties of the liquid-gas phase
transition. In this contribution, we address the effect of Coulomb and isospin
dependence interaction for the finite nuclei transition, and study the symmetry
energy properties of finite temperature systems.


title:
Circumstellar Na I and Ca II lines of type Ia supernovae in symbiotic
  scenario

abstract:
  Formation of circumstellar lines of Na I and Ca II in type Ia supernovae is
studied for the case, when supernova explodes in a binary system with a red
giant. The model suggests a spherically-symmetric wind and takes into account
ionization and heating of the wind by X-rays from the shock wave and by
gamma-quanta of ^{56}Ni radioactive decay. For the wind density typical of the
red giant the expected optical depth of the wind in Na I lines turnes out too
low (\tau<0.001}) to detect the absorption. For the same wind densities the
predicted optical depth of Ca II 3934 \AA is sufficient for the detection
(\tau>0.1). I conclude that the absorption lines detected in SN 2006X cannot
form in the red giant wind; they are rather related to clouds at distances
larger than the dust evaporation radius (r>10^{17} cm). From the absence in SN
2006X of Ca II absorption lines not related with the similar Na I components I
derive the upper limit of the mass loss rate by the wind with velocity u:
\dot{M}<10^{-8}(u/10 km/s) M_{\odot} yr^{-1}.


title: Superconductivity in undoped T'-RE2CuO4 with Tc over 30 K

abstract:
  In this article, we report the superconductivity in T'-RE2CuO4 (RE = Pr, Nd,
Sm, Eu, and Gd), which have been for a long time believed as a Mott insulator.
Our discovery was achieved by using metal-organic decomposition (MOD), an
inexpensive and easy-to-implement thin-film process. The keys to prepare the
superconducting films are firing with low partial-pressure of oxygen and
reduction at low temperatures. The highest Tc of undoped T'-RE2CuO4 is over 30
K, substantially higher than "electron-doped" analogs. Remarkably, Gd2CuO4,
even the derivatives of which have not shown superconductivity so far, gets
superconducting with Tconset as high as 20 K. The implication of our discovery
is briefly discussed.


title: Testing for Subcellular Randomness

abstract:
  Statistical tests were conducted on 1,000 numbers generated from the genome
of Bacteriophage T4, obtained from GenBank with accession number AF158101.The
numbers passed the non-parametric, distribution-free tests.Deoxyribonucleic
acid was discovered to be a random number generator, existent in nature.


title: Unparticle as a particle with arbitrary mass

abstract:
  The unparticle field operator can be expanded in terms of creation and
destruction operators corresponding to particles with a continuous mass
spectrum. Hence, when the 4-momentum of an unparticle is measured, then the
unparticle manifests as an ordinary particle with a definite (but arbitrary)
mass.


title:
Belief revision in quantum decision theory: gambler's and hot hand
  fallacies

abstract:
  In the present article we introduce a quantum mechanism which is able to
describe the creation of correlations in the evaluation of random independent
events: such correlations, known as positive and negative recency, correspond
respectively to the hot hand's and to the gambler's fallacies. Thus we propose
a description of these effects in terms of qubits, which may become entangled,
forming a system which can not be described completely only in terms of its
constituents. We show that such formalism is able to describe and interpret the
experimental results, thus providing a general and unifying framework for the
cognitive heuristics.


title:
Microlensing of the X-ray, UV and optical emission regions of quasars:
  Simulations of the time-scales and amplitude variations of microlensing
  events

abstract:
  We consider the influence of microlensing on different spectral bands of
lensed QSOs. We assumed that the emitting X-ray, UV and optical regions are
different in size, but that the continuum emission in these spectral bands is
originating from an accretion disc. Estimations of the time scales for
microlensing and flux amplification in different bands are given. We found that
the microlensing duration should be shorter in the X-ray (several months) than
in UV/optical emitting region (several years). This result indicates that
monitoring of the X-ray variations in lensed QSOs that show a 'flux anomaly'
can clarify the source of this anomaly.


title: 2MASS J01542930+0053266 : A New Eclipsing M-dwarf Binary System

abstract:
  We report on 2MASS J01542930+0053266, a faint eclipsing system composed of
two M dwarfs. The variability of this system was originally discovered during a
pilot study of the 2MASS Calibration Point Source Working Database. Additional
photometry from the Sloan Digital Sky Survey yields an 8-passband lightcurve,
from which we derive an orbital period of 2.6390157 +/- 0.0000016 days.
Spectroscopic followup confirms our photometric classification of the system,
which is likely composed of M0 and M1 dwarfs. Radial velocity measurements
allow us to derive the masses (M_1 = 0.66 +/- 0.03 M_sun; M_2 = 0.62 +/- 0.03
M_sun) and radii (R_1 = 0.64 +/- 0.08 R_sun; R_2 = 0.61 +/- 0.09 R_sun) of the
components, which are consistent with empirical mass-radius relationships for
low-mass stars in binary systems. We perform Monte Carlo simulations of the
lightcurves which allow us to uncover complicated degeneracies between the
system parameters. Both stars show evidence of H-alpha emission, something not
common in early-type M dwarfs. This suggests that binarity may influence the
magnetic activity properties of low-mass stars; activity in the binary may
persist long after the dynamos in their isolated counterparts have decayed,
yielding a new potential foreground of flaring activity for next generation
variability surveys.


title: Adiabatic quenches through an extended quantum critical region

abstract:
  By gradually changing the degree of the anisotropy in a XXZ chain we study
the defect formation in a quantum system that crosses an extended critical
region. We discuss two qualitatively different cases of quenches, from the
antiferromagnetic to the ferromagnetic phase and from the critical to the
antiferromegnetic phase. By means of time-dependent DMRG simulations, we
calculate the residual energy at the end of the quench as a characteristic
quantity gauging the loss of adiabaticity. We find the dynamical scalings of
the residual energy for both types of quenches, and compare them with the
predictions of the Kibble-Zurek and Landau-Zener theories.


abstract:
  Necessary and sufficient conditions for Lipschitzness of the Lempert and
Green functions are found in terms of their boundary behaviors.


title: Time and Observables in Unimodular General Relativity

abstract:
  A cosmological time variable is emerged from the hamiltonian formulation of
unimodular theory of gravity to measure the evolution of dynamical observables
in the theory. A set of constants of motion has been identified for the theory
on the null hypersurfaces that its evolution is with respect to the volume
clock introduced by the cosmological time variable.


title:
Thermodynamical Interpretation of the Interacting Holographic Dark
  Energy Model in a non-flat Universe

abstract:
  Motivated by the recent work of Wang, Lin, Pavon, and Abdalla [1], we
generalize their work to the non-flat case. In particular, we provide a
thermodynamical interpretation for the holographic dark energy model in a
non-flat universe. For this case, the characteristic length is no more the
radius of the event horizon (R_E) but the event horizon radius as measured from
the sphere of the horizon (L). Furthermore, when interaction between the dark
components of the holographic dark energy model in the non-flat universe is
present its thermodynamical interpretation changes by a stable thermal
fluctuation. A relation between the interaction term of the dark components and
this thermal fluctuation is obtained. In the limiting case of a flat universe,
i.e. k=0, all results given in [1] are obtained.


title: Spontaneous symmetry breakdown in fuzzy spheres

abstract:
  We study and analyse the questions regarding breakdown of global symmetry on
noncommutative sphere. We demonstrate this by considering a complex scalar
field on a fuzzy sphere and isolating Goldstone modes. We discuss the role of
nonlocal interactions present in these through geometrical considerations.


title: Abstractions for biomolecular computations

abstract:
  Deoxyribonucleic acid is increasingly being understood to be an informational
molecule, capable of information processing.It has found application in the
determination of non-deterministic algorithms and in the design of molecular
computing devices. This is a theoretical analysis of the mathematical
properties and relations of the molecules which constituting DNA, which
explains in part why DNA is a successful computing molecule.


title: Energy of interaction between solid surfaces and liquids

abstract:
  We consider the wetting transition on a planar surface in contact with a
semi-infinite fluid. In the classical approach, the surface is assumed to be
solid, and when interaction between solid and fluid is sufficiently
short-range, the contribution of the fluid can be represented by a surface free
energy with a density of the form Phi(rho_s), where rho_s is the limiting
density of the fluid at the surface. In the present paper we propose a more
precise representation of the surface energy that takes into account not only
the value of rho_s but also the contribution from the whole density profile
rho(z) of the fluid, where z is the coordinate normal to the surface. The
specific value of the functional of rho_s at the surface is expressed in
mean-field approximation through the potentials of intermolecular interaction
and some other parameters of the fluid and the solid wall. An extension to the
case of fluid mixtures in contact with a solid surface is proposed.


title: Photoinduced dynamics in protonated aromatic amino acid

abstract:
  UV photoinduced fragmentation of protonated aromatics amino acids have
emerged the last few years, coming from a situation where nothing was known to
what we think a good understanding of the optical properties. We will mainly
focus this review on the tryptophan case. Three groups have mostly done
spectroscopic studies and one has mainly been involved in dynamics studies of
the excited states in the femtosecond/picosecond range and also in the
fragmentation kinetics from nanosecond to millisecond. All these data, along
with high level ab initio calculations, have shed light on the role of the
different electronic states of the protonated molecules upon the fragmentation
mechanisms.


title:
Biopsies prostatiques sous guidage \'echographique 3D et temps r\'eel
  (4D) sur fant\^ome. Etude comparative versus guidage 2D

abstract:
  This paper analyzes the impact of using 2D or 3D ultrasound on the efficiency
of prostate biopsies. The evaluation is performed on home-made phantoms. The
study shows that the accuracy is significantly improved.


title:
The Ring Imaging Cherenkov detector of the AMS experiment: test beam
  results with a prototype

abstract:
  The Alpha Magnetic Spectrometer (AMS) to be installed on the International
Space Station (ISS) will be equipped with a proximity Ring Imaging Cherenkov
(RICH) detector for measuring the velocity and electric charge of the charged
cosmic particles. This detector will contribute to the high level of redundancy
required for AMS as well as to the rejection of albedo particles. Charge
separation up to iron and a velocity resolution of the order of 0.1% for singly
charged particles are expected. A RICH protoptype consisting of a detection
matrix with 96 photomultiplier units, a segment of a conical mirror and samples
of the radiator materials was built and its performance was evaluated. Results
from the last test beam performed with ion fragments resulting from the
collision of a 158 GeV/c/nucleon primary beam of indium ions (CERN SPS) on a
lead target are reported. The large amount of collected data allowed to test
and characterize different aerogel samples and the sodium fluoride radiator. In
addition, the reflectivity of the mirror was evaluated. The data analysis
confirms the design goals.


title:
Critical temperature for the nuclear liquid-gas phase transition (from
  multifragmentation and fission)

abstract:
  Critical temperature Tc for the nuclear liquid-gas phase transition is
stimated both from the multifragmentation and fission data. In the first
case,the critical temperature is obtained by analysis of the IMF yields in
p(8.1 GeV)+Au collisions within the statistical model of multifragmentation
(SMM). In the second case, the experimental fission probability for excited
188Os is compared with the calculated one with Tc as a free parameter. It is
concluded for both cases that the critical temperature is higher than 16 MeV.


title: Modeling Bell's Non-resonant Cosmic Ray Instability

abstract:
  We have studied the non-resonant streaming instability of charged energetic
particles moving through a background plasma, discovered by Bell (2004). We
confirm his numerical results regarding a significant magnetic field
amplification in the system. A detailed physical picture of the instability
development and of the magnetic field evolution is given.


title: Universal quantum dynamics from two 2-local Hamiltonians

abstract:
  In this paper, we show that the ability to switch globally between two
2-local Hamiltonians on n qubits is sufficient for achieving universal unitary
dynamics on those n qubits. Of the two Hamiltonians used in the construction,
one is comprised of nearest-neighbour two-qubit interactions on a
one-dimensional chain, the other is comprised of single-qubit interactions. We
describe a scheme for choosing the switching times in order to generate
arbitrary one- and two-qubit gates on the n qubits. However the switching
scheme is inefficient, and we leave as an open problem the question of whether
the universality of the Hamiltonians can be exploited in an efficient way.


title:
Diffusive Shock Acceleration with Magnetic Amplification by Non-resonant
  Streaming Instability in SNRs

abstract:
  We investigate the diffusive shock acceleration in the presence of the
non-resonant streaming instability introduced by Bell (2004). The numerical MHD
simulations of the magnetic field amplification combined with the analytical
treatment of cosmic ray acceleration permit us to calculate the maximum energy
of particles accelerated by high-velocity supernova shocks. The estimates for
Cas A, Kepler, SN1006, and Tycho historical supernova remnants are given. We
also found that the amplified magnetic field is preferentially oriented
perpendicular to the shock front downstream of the fast shock. This explains
the origin of the radial magnetic fields observed in young supernova remnants.


title:
Multiple scattering effects in quasi free scattering from halo nuclei: a
  test to Distorted Wave Impulse Approximation

abstract:
  Full Faddeev-type calculations are performed for $^{11}$Be breakup on proton
target at 38.4, 100, and 200 MeV/u incident energies. The convergence of the
multiple scattering expansion is investigated. The results are compared with
those of other frameworks like Distorted Wave Impulse Approximation that are
based on an incomplete and truncated multiple scattering expansion.


title: Fidelity decay in trapped Bose-Einstein condensates

abstract:
  The quantum coherence of a Bose-Einstein condensate is studied using the
concept of quantum fidelity (Loschmidt echo). The condensate is confined in an
elongated anharmonic trap and subjected to a small random potential such as
that created by a laser speckle. Numerical experiments show that the quantum
fidelity stays constant until a critical time, after which it drops abruptly
over a single trap oscillation period. The critical time depends
logarithmically on the number of condensed atoms and on the perturbation
amplitude. This behavior may be observable by measuring the interference
fringes of two condensates evolving in slightly different potentials.


title:
Nitrogen enrichment, boron depletion and magnetic fields in
  slowly-rotating B-type dwarfs

abstract:
  Evolutionary models for massive stars, accounting for rotational mixing
effects, do not predict any core-processed material at the surface of B dwarfs
with low rotational velocities. Contrary to theoretical expectations, we
present a detailed and fully-homogeneous, NLTE abundance analysis of 20 early
B-type dwarfs and (sub)giants that reveals the existence of a population of
nitrogen-rich and boron-depleted, yet intrinsically slowly-rotating objects.
The low-rotation rate of several of these stars is firmly established, either
from the occurrence of phase-locked UV wind line-profile variations, which can
be ascribed to rotational modulation, or from theoretical modelling in the
pulsating variables. The observational data presently available suggest a
higher incidence of chemical peculiarities in stars with a (weak) detected
magnetic field. This opens the possibility that magnetic phenomena are
important in altering the photospheric abundances of early B dwarfs, even for
surface field strengths at the one hundred Gauss level. However, further
spectropolarimetric observations are needed to assess the validity of this
hypothesis.


title:
Can photo-ionization explain the decreasing fraction of X-ray obscured
  AGN with luminosity?

abstract:
  Chandra and XMM surveys show that the fraction of obscured AGN decreases
rapidly with increasing luminosity. Although this is usually explained by
assuming that the covering factor of the central engine is much smaller at
luminous QSOs, the exact origin of this effect remains unknown. We perform toy
simulations to test whether photo-ionisation of the obscuring screen in the
presence of a strong radiation field can reproduce this effect. In particular,
we create X-ray spectral simulations using a warm absorber model assuming a
range of input column densities and ionization parameters. We fit instead the
simulated spectra with a simple cold absorption power-law model that is the
standard practice in X-ray surveys. We find that the fraction of absorbed AGN
should fall with luminosity as $L^{-0.16\pm0.03}$ in rough agreement with the
observations. Furthermore, this apparent decrease in the obscuring material is
consistent with the dependence of the FeK$\alpha$ narrow-line equivalent width
on luminosity, ie. the X-ray Baldwin effect.


title: Ethynyl (C2H) in massive star formation: Tracing the initial conditions?

abstract:
  APEX single-dish observations at sub-millimeter wavelengths toward a sample
of massive star-forming regions reveal that C2H is almost omni-present toward
all covered evolutionary stages from Infrared Dark Clouds via High-Mass
Protostellar Objects to Ultracompact HII regions. High-resolution data from the
Submillimeter Array toward one hot-core like High-Mass Protostellar Object show
a shell-like distribution of C2H with a radius of ~9000AU around the central
submm peak position. These observed features are well reproduced by a 1D cloud
model with power-law density and temperature distributions and a gas-grain
chemical network. The reactive C2H radical (ethynyl) is abundant from the onset
of massive star formation, but later it is rapidly transformed to other
molecules in the core center. In the outer cloud regions the abundance of C2H
remains high due to constant replenishment of elemental carbon from CO being
dissociated by the interstellar UV photons. We suggest that C2H may be a
molecule well suited to study the initial conditions of massive star formation.


title:
The simplest and fastest method of solving Exact Differential Equation
  by developing the idea of Basic Functions

abstract:
  This paper concerns exact differential equations. First, I define two types
of functions which I have named Basic Function of Type One and Basic Function
of Type Two. I then derive the property and theorems of these functions.
Finally, by applying the property and theorems of Basic Functions, I establish
the method of solving exact differential equation with n variables which is
significantly simpler and faster than the standard method.


title:
Nucleon-to-Delta axial transition form factors in relativistic baryon
  chiral perturbation theory

abstract:
  We report a theoretical study of the axial Nucleon to Delta(1232)
($N\to\Delta$) transition form factors up to one-loop order in relativistic
baryon chiral perturbation theory. We adopt a formalism in which the $\Delta$
couplings obey the spin-3/2 gauge symmetry and, therefore, decouple the
unphysical spin-1/2 fields. We compare the results with phenomenological form
factors obtained from neutrino bubble chamber data and in quark models.


title:
Barnes slave boson approach to the two-site single impurity Anderson
  model with non-local interaction

abstract:
  The Barnes slave boson approach to the $U=\infty$ single impurity Anderson
model extended by a non-local Coulomb interaction is revisited. We demonstrate
first that the radial gauge representation facilitates the treatment of such a
non-local interaction by performing the \emph{exact} evaluation of the path
integrals representing the partition function, the impurity hole density and
the impurity hole density autocorrelation function for a two-site cluster. The
free energy is also obtained on the same footing. Next, the exact results are
compared to their approximations at saddle-point level, and it is shown that
the saddle point evaluation recovers the exact answer in the limit of strong
non-local Coulomb interaction, while the agreement between both schemes remains
satisfactory in a large parameter range.


title: Controlled decoherence in a quantum L\'evy kicked rotator

abstract:
  We develop a theory describing the dynamics of quantum kicked rotators
(modelling cold atoms in a pulsed optical field) which are subjected to
combined amplitude and timing noise generated by a renewal process (acting as
an engineered reservoir). For waiting-time distributions of variable exponent
(L\'evy noise), we demonstrate the existence of a regime of nonexponential loss
of phase coherence. In this regime, the momentum dynamics is subdiffusive,
which also manifests itself in a non-Gaussian limiting distribution and a
fractional power-law decay of the inverse participation ratio. The purity
initially decays with a stretched exponential which is followed by two regimes
of power-law decay with different exponents. The averaged logarithm of the
fidelity probes the sprinkling distribution of the renewal process. These
analytical results are confirmed by numerical computations on quantum kicked
rotators subjected to noise events generated by a Yule-Simon distribution.


title:
Comment on "Quantum Monte Carlo scheme for frustrated Heisenberg
  antiferromagnets"

abstract:
  Quantum Monte Carlo methods are sophisticated numerical techniques for
simulating interacting quantum systems. In some cases, however, they suffer
from the notorious "sign problem" and become too inefficient to be useful. A
recent publication [J. Wojtkiewicz, Phys. Rev. B 75, 174421 (2007)] claims to
have solved the sign problem for a certain class of frustrated quantum spin
systems through the use of a bipartite valence bond basis. We show in this
Comment that the apparent positivity of the path integral is due to a
misconception about the resolution of the identity operator in this basis, and
that consequently the sign problem remains a severe obstacle for the simulation
of frustrated quantum magnets.


title:
On the birth-and-assassination process, with an application to scotching
  a rumor in a network

abstract:
  We give new formulas on the total number of born particles in the stable
birth-and-assassination process, and prove that it has an heavy-tailed
distribution. We also establish that this process is a scaling limit of a
process of rumor scotching in a network, and is related to a predator-prey
dynamics.


title: On the motion under focal attraction in a rotating medium

abstract:
  New results are established here on the phase portraits and bifurcations of
the kinematic model in a system of ODE's, first presented by H.K. Wilson in his
1971 book, and by him attributed to L. Markus (unpublished). A new,
self-sufficient, study which extends Wilson's result and allows an essential
conclusion for the applicability of the model is reported here.


title: Zero-Range Processes with Multiple Condensates: Statics and Dynamics

abstract:
  The steady-state distributions and dynamical behaviour of Zero Range
Processes with hopping rates which are non-monotonic functions of the site
occupation are studied. We consider two classes of non-monotonic hopping rates.
The first results in a condensed phase containing a large (but subextensive)
number of mesocondensates each containing a subextensive number of particles.
The second results in a condensed phase containing a finite number of extensive
condensates. We study the scaling behaviour of the peak in the distribution
function corresponding to the condensates in both cases. In studying the
dynamics of the condensate we identify two timescales: one for creation, the
other for evaporation of condensates at a given site. The scaling behaviour of
these timescales is studied within the Arrhenius law approach and by numerical
simulations.


title:
Submillimetre point sources from the Archeops experiment: Very Cold
  Clumps in the Galactic Plane

abstract:
  Archeops is a balloon-borne experiment, mainly designed to measure the Cosmic
Microwave Background (CMB) temperature anisotropies at high angular resolution
(~ 12 arcminutes). By-products of the mission are shallow sensitivity maps over
a large fraction of the sky (about 30 %) in the millimetre and submillimetre
range at 143, 217, 353 and 545 GHz. From these maps, we produce a catalog of
bright submillimetre point sources. We present in this paper the processing and
analysis of the Archeops point sources. Redundancy across detectors is the key
factor allowing to sort out glitches from genuine point sources in the 20
independent maps. We look at the properties of the most reliable point sources,
totalling 304. Fluxes range from 1 to 10,000 Jy (at the frequencies covering
143 to 545 GHz). All sources are either planets (2) or of galactic origin.
Longitude range is from 75 to 198 degrees. Some of the sources are associated
with well-known Lynds Nebulae and HII compact regions in the galactic plane. A
large fraction of the sources have an IRAS counterpart. Except for Jupiter,
Saturn, the Crab and Cas A, all sources show a dust-emission-like modified
blackbody emission spectrum. Temperatures cover a range from 7 to 27 K. For the
coldest sources (T<10 K), a steep nu^beta emissivity law is found with a
surprising beta ~ 3 to 4. An inverse relationship between T and beta is
observed. The number density of sources at 353 GHz with flux brighter than 100
Jy is of the order of 1 per degree of Galactic longitude. These sources will
provide a strong check for the calibration of the Planck HFI focal plane
geometry as a complement to planets. These very cold sources observed by
Archeops should be prime targets for mapping observations by the Akari and
Herschel space missions and ground--based observatories.


title: Non-archimedean canonical measures on abelian varieties

abstract:
  For a closed d-dimensional subvariety X of an abelian variety A and a
canonically metrized line bundle L on A, Chambert-Loir has introduced measures
$c_1(L|_X)^{\wedge d}$ on the Berkovich analytic space associated to A with
respect to the discrete valuation of the ground field. In this paper, we give
an explicit description of these canonical measures in terms of convex
geometry. We use a generalization of the tropicalization related to the Raynaud
extension of A and Mumford's construction. The results have applications to the
equidistribution of small points.


title: Critical review of [K- ppn] bound states

abstract:
  We make a thorough study of the process of three body kaon absorption in
nuclei, in connection with a recent FINUDA experiment which claims the
existence of a deeply bound kaonic state from the observation of a peak in the
Lambda d invariant mass distribution following K- absorption on Li6. We show
that the peak is naturally explained in terms of K- absorption from three
nucleons leaving the rest as spectators. We can also reproduce all the other
observables measured in the same experiment and used to support the hypothesis
of the deeply bound kaon state. Our study also reveals interesting aspects of
kaon absorption in nuclei, a process that must be understood in order to make
progress in the search for K- deeply bound states in nuclei.


title: Limits on the Position Wander of Sgr A*

abstract:
  We present measurements with the VLBA of the variability in the centroid
position of Sgr A* relative to a background quasar at 7-mm wavelength. We find
an average centroid wander of 71 +/- 45 micro-arcsec for time scales between 50
and 100 min and 113 +/- 50 micro-arcsec for timescales between 100 and 200 min,
with no secular trend. These are sufficient to begin constraining the viability
of the hot-spot model for the radio variability of Sgr A*. It is possible to
rule out hot spots with orbital radii above 15GM_SgrA*/c^2 that contribute more
than 30% of the total 7-mm flux. However, closer or less luminous hot spots
remain unconstrained. Since the fractional variability of Sgr A* during our
observations was ~20% on time scales of hours, the hot-spot model for Sgr A*'s
radio variability remains consistent with these limits. Improved monitoring of
Sgr A*'s centroid position has the potential to place significant constraints
upon the existence and morphology of inhomogeneities in a supermassive black
hole accretion flow.


title: Pairing Glue in the Hubbard and t-J Models

abstract:
  The question of whether one should speak of a "pairing glue" in the Hubbard
and t-J models is basically a question about the dynamics of the pairing
interaction. If the dynamics of the pairing interaction arises from virtual
states, whose energies correspond to the Mott gap, and give rise to the
exchange coupling J, the interaction is instantaneous on the relative time
scales of interest. In this case, while one might speak of an "instantaneous
glue", this interaction differs from the traditional picture of a retarded
pairing interaction. However, if the energies correspond to the spectrum seen
in the dynamic spin susceptibility, then the interaction is retarded and one
speaks of a spin-fluctuation glue which mediates the d-wave pairing. Here we
present results from numerical studies which provide insight into this
question.


title:
Systematic renormalization scheme in light-front dynamics with Fock
  space truncation

abstract:
  Within the framework of the covariant formulation of light-front dynamics, we
develop a general non-perturbative renormalization scheme based on the Fock
decomposition of the state vector and its truncation. The counterterms and bare
parameters needed to renormalize the theory depend on the Fock sectors. We
present a general strategy in order to calculate these quantities, as well as
state vectors of physical systems, in a truncated Fock space. The explicit
dependence of our formalism on the orientation of the light front plane is
essential in order to analyze the structure of the counterterms. We apply our
formalism to the two-body (one fermion and one boson) truncation in the Yukawa
model and in QED, and to the three-body truncation in a scalar model. In QED,
we recover analytically, without any perturbative expansion, the
renormalization of the electric charge, according to the requirements of the
Ward identity.


title: Equidistribution over function fields

abstract:
  We prove equidistribution of a generic net of small points in a projective
variety X over a function field K. For an algebraic dynamical system over K, we
generalize this equidistribution theorem to a small generic net of
subvarieties. For number fields, these results were proved by Yuan and we
transfer here his methods to function fields. If X is a closed subvariety of an
abelian variety, then we can describe the equidistribution measure explicitly
in terms of convex geometry.


title: SiLC simulation status report

abstract:
  The SiLC - Silicon for the Linear Collider - collaboration aims to develop
silicon detector technology for tracking in the international linear collider
experiments. The R & D programme involves a substantial effort in simulation of
the response of detector designs. In this contribution, an overview of ongoing
efforts in this area is given.


title:
The Wigner distribution function for the one-dimensional parabose
  oscillator

abstract:
  In the beginning of the 1950's, Wigner introduced a fundamental deformation
from the canonical quantum mechanical harmonic oscillator, which is nowadays
sometimes called a Wigner quantum oscillator or a parabose oscillator. Also, in
quantum mechanics the so-called Wigner distribution is considered to be the
closest quantum analogue of the classical probability distribution over the
phase space. In this article, we consider which definition for such
distribution function could be used in the case of non-canonical quantum
mechanics. We then explicitly compute two different expressions for this
distribution function for the case of the parabose oscillator. Both expressions
turn out to be multiple sums involving (generalized) Laguerre polynomials.
Plots then show that the Wigner distribution function for the ground state of
the parabose oscillator is similar in behaviour to the Wigner distribution
function of the first excited state of the canonical quantum oscillator.


title:
A Correlation between Blue Straggler and Binary Fractions in the core of
  Galactic Globular Clusters

abstract:
  Context. Blue Stragglers Stars (BSSs) are thought to form in globular
clusters by two main formation channels: i) mergers induced by stellar
collisions and ii) coalescence or mass-transfer between companions in binary
systems. The detailed study of the BSS properties is therefore crucial for
understanding the binary evolution mechanisms, and the complex interplay
between dynamics and stellar evolution in dense stellar systems. Aims. We
present the first comparison between the BSS specific frequency and the binary
fraction in the core of a sample of Galactic globular clusters, with the aim of
investigating the relative efficiency of the two proposed formation mechanisms.
Methods. We derived the frequency of BSSs in the core of thirteen low-density
Galactic globular clusters by using deep ACS@HST observations and investigated
its correlation with the binary fraction and various other cluster parameters.
Results. We observed a correlation between the BSS specific frequency and the
binary fraction. The significance of the correlation increases by including a
further dependence on the cluster central velocity dispersion. Conclusions. We
conclude that the unperturbed evolution of primordial binaries could be the
dominant BSS formation process, at least in low-density environments.


title:
Competition of coalescence and "fireball" processes in nonequilibrium
  emission of light charged particles from p+Au collisions

abstract:
  The energy and angular dependence of double differential cross sections was
measured for p,d,t,He,Li,Be, and B isotopes produced in collisions of 1.2 and
1.9 GeV protons with Au target. The shape of the spectra and angular
distributions almost does not change in the beam energy range from 1.2 to 2.5
GeV, however, the absolute value of the cross sections increases for all
ejectiles. A phenomenological model of two emitting, moving sources reproduces
very well spectra and angular distributions of intermediate mass fragments.
Double differential cross sections for light charged particles (LCP) were
analyzed in the frame of the microscopic model of intranuclear cascade (INC)
with coalescence of nucleons and statistical model for evaporation of particles
from excited residual nuclei. Energy and angular dependencies of data agree
satisfactorily neither with predictions of microscopic intranuclear cascade
calculations for protons, nor with coalescence calculations for other LCP.
Phenomenological inclusion of another reaction mechanism - emission of LCP from
a "fireball", i.e., fast and hot moving source - combined with the microscopic
model calculations of INC, coalescence and evaporation of particles leads to
very good description of the data. It was found that nonequilibrium processes
are very important for production of LCP. They exhaust 40-80% of the total
cross sections - depending on the emitted particles. Coalescence and "fireball"
emission give comparable contributions to the cross sections with exception of
3He data where coalescence clearly dominates. The ratio of sum of all
nonequilibrium processes to those proceeding through stage of statistical
equilibrium does almost not change in the beam energy range from 1.2 GeV to 2.5
GeV for all light charged particles.


title: Disorder-induced orbital ordering in doped manganites

abstract:
  We study the effect of quenched disorder on the ordering of orbital and
magnetic degrees of freedom in a two-dimensional, two-band double-exchange
model for $e_g$ electrons coupled to Jahn-Teller distortions. Using a
real-space Monte Carlo method, we find that disorder can induce a short-range
ordering of the orbital degrees of freedom near 30% hole doping. The most
striking consequence of this short range ordering is a strong increase in the
low temperature resistivity. The real-space approach allows to analyze the
spatial patterns of the charge, orbital, and magnetic degrees of freedom, and
the correlations among them. The magnetism is inhomogeneous on the nanoscale in
the short-range orbitally ordered state.


title:
Charged particle interferometry in Pleba\'{n}ski--Demia\'{n}ski black
  hole space--times

abstract:
  The Pleba\'{n}ski--Demia\'{n}ski solution is a very general axially symmetric
analytical solution of the Einstein field equations generalizing the Kerr
solution. This solution depends on seven parameters which under certain
circumstances are related to mass, rotation, cosmological constant, NUT
parameter, electric and magnetic charges, and acceleration. In this paper we
present a general description of matter wave interferometry in the general
Pleba\'{n}ski--Demia\'{n}ski black hole space--time. Particular emphasis is
placed on a gauge invariant description of the symmetries of the gauge field.
We show that it is possible to have access to all parameters separately except
the acceleration. For neutral particles there is only access to a combination
of electric and magnetic charge.


title: Quantum walks: a Markovian perspective

abstract:
  For a continuous-time quantum walk on a line the variance of the position
observable grows quadratically in time, whereas, for its classical counterpart
on the same graph, it exhibits a linear, diffusive, behaviour. A quantum walk,
thus, propagates at a rate which is linear in time, as compared to the square
root rate for a classical random walk. Indeed, it has been suggested that there
are graphs that can be traversed by a quantum walker exponentially faster than
by the classical random analogue. In this note we adopt the approach of
exploring the conditions to impose on a Markov process in order to emulate its
quantum counterpart: the central issue that emerges is the problem of taking
into account, in the numerical generation of each sample path, the causative
effect of the ensemble of trajectories to which it belongs. How to deal
numerically with this problem is shown in a paradigmatic example.


title:
Searching for a Correlation Between Cosmic-Ray Sources Above 10^{19} eV
  and Large-Scale Structure

abstract:
  We study the anisotropy signature which is expected if the sources of ultra
high energy, >10^{19} eV, cosmic-rays (UHECRs) are extragalactic and trace the
large scale distribution of luminous matter. Using the PSCz galaxy catalog as a
tracer of the large scale structure (LSS), we derive the expected all sky
angular distribution of the UHECR intensity. We define a statistic, that
measures the correlation between the predicted and observed UHECR arrival
direction distributions, and show that it is more sensitive to the expected
anisotropy signature than the power spectrum and the two point correlation
function. The distribution of the correlation statistic is not sensitive to the
unknown redshift evolution of UHECR source density and to the unknown strength
and structure of inter-galactic magnetic fields. We show, using this statistic,
that recently published >5.7x10^{19} eV Auger data are inconsistent with
isotropy at ~98% CL, and consistent with a source distribution that traces LSS,
with some preference to a source distribution that is biased with respect to
the galaxy distribution. The anisotropy signature should be detectable also at
lower energy, >4x10^{19} eV. A few fold increase of the Auger exposure is
likely to increase the significance to >99% CL, but not to >99.9% CL (unless
the UHECR source density is comparable or larger than that of galaxies). In
order to distinguish between different bias models, the systematic uncertainty
in the absolute energy calibration of the experiments should be reduced to well
below the current ~25%.


title: The Integrated Sachs-Wolfe Effect in Interacting Dark Energy Models

abstract:
  Models with dark energy decaying into dark matter have been proposed in
Cosmology to solve the coincidence problem. We study the effect of such
coupling on the cosmic microwave background temperature anisotropies. The
interaction changes the rate of evolution of the metric potentials, the growth
rate of matter density perturbations and modifies the Integrated Sachs-Wolfe
component of cosmic microwave background temperature anisotropies, enhancing
the effect. Cross-correlation of galaxy catalogs with CMB maps provides a model
independent test to constrain the interaction. We particularize our analysis
for a specific interacting model and show that galaxy catalogs with median
redshifts $z_m=0.1-0.9$ can rule out models with an interaction parameter
strength of $c^2\simeq 0.1$ better than 99.95% confidence level. Values of
$c^2\le 0.01$ are compatible with the data and may account for the possible
discrepancy between the fraction of dark energy derived from WMAP 3yr data and
the fraction obtained from the ISW effect. Measuring the fraction of dark
energy by these two methods could provide evidence of an interaction.


title:
Anisotropic magnetization studies of $R_2 Co Ga_8$ (R = Gd, Tb, Dy, Ho,
  Er, Tm, Y and Lu) single crystals

abstract:
  Single crystals of R$_2$CoGa$_8$ series of compounds were grown, for the
first time, by high temperature solution growth (flux) method. These compounds
crystallize in a tetragonal crystal structure with the space group $P4/mmm$. It
has been found that R$_2$CoGa$_8$ phase forms only with the heavier rare
earths, starting from Gd with a relatively large $c/a$ ratio of $\approx$ 2.6.
The resultant anisotropic magnetic properties of the compounds were
investigated along the two principal crystallographic directions of the crystal
viz., along [100] and [001]. The nonmagnetic compounds Y$_2$CoGa$_8$ and
Lu$_2$CoGa$_8$ show diamagnetic behavior down to the lowest temperature (1.8 K)
pointing out the non-magnetic nature of Co in these compounds and a relatively
low density of electronic states at the Fermi level. Compounds with the
magnetic rare earths order antiferromagnetically at temperatures lower than 30
K. The easy axis of magnetization for R$_2$CoGa$_8$ (R = Tb, Dy and Ho) is
found to be along the [001] direction and it changes to [100] direction for
Er$_2$CoGa$_8$ and Tm$_2$CoGa$_8$. The magnetization behavior is analyzed on
the basis of crystalline electric field (CEF) model. The estimated crystal
field parameters explains the magnetocrystalline anisotropy in this series of
compounds.


title:
Comparing magnetic field extrapolations with measurements of magnetic
  loops

abstract:
  We compare magnetic field extrapolations from a photospheric magnetogram with
the observationally inferred structure of magnetic loops in a newly developed
active region. This is the first time that the reconstructed 3D-topology of the
magnetic field is available to test the extrapolations. We compare the
observations with potential fields, linear force-free fields and non-linear
force-free fields. This comparison reveals that a potential field extrapolation
is not suitable for a reconstruction of the magnetic field in this young,
developing active region. The inclusion of field-line-parallel electric
currents, the so called force-free approach, gives much better results.
Furthermore, a non-linear force-free computation reproduces the observations
better than the linear force-free approximation, although no free parameters
are available in the former case.


title: Recent Experimental Results from JLab

abstract:
  Preliminary results of a selected few recent experiments at JLab are
presented.


title: Gauging isometries in N=4 supersymmetric mechanics

abstract:
  This talk summarizes the study of superfield gaugings of isometries of
extended supersymmetric mechanics in hep-th/0605211, hep-th/0611247 and
arXiv:0706.0706. The gauging procedure provides a manifestly supersymmetric
realization of d=1 automorphic dualities which interrelate various irreducible
off-shell multiplets of d=1 extended supersymmetry featuring the same number of
physical fermions but different divisions of bosonic fields into the physical
and auxiliary subsets. We concentrate on the most interesting N=4 case and
demonstrate that, with a suitable choice of the symmetry to be gauged, all such
multiplets of N=4 supersymmetric mechanics and their generic superfield actions
can be obtained from the "root" multiplet (4,4,0) and the appropriate gauged
subclasses of the generic superfield action of the latter by a simple universal
recipe.


title: The Inverse Simpson Paradox (How To Win Without Overtly Cheating)

abstract:
  Given two sets of data which lead to a similar statistical conclusion, the
Simpson Paradox describes the tactic of combining these two sets and achieving
the opposite conclusion. Depending upon the given data, this may or may not
succeed. Inverse Simpson is a method of decomposing a given set of comparison
data into two disjoint sets and achieving the opposite conclusion for each one.
This is always possible; however, the statistical significance of the
conclusions does depend upon the details of the given data.


title:
Transverse coherence properties of X-ray beams in third-generation
  synchrotron radiation sources

abstract:
  This article describes a complete theory of spatial coherence for undulator
radiation sources. Current estimations of coherence properties often assume
that undulator sources are quasi-homogeneous, like thermal sources, and rely on
the application of the van Cittert-Zernike theorem for calculating the degree
of transverse coherence. Such assumption is not adequate when treating third
generation light sources, because the vertical(geometrical) emittance of the
electron beam is comparable or even much smaller than the radiation wavelength
in a very wide spectral interval that spans over four orders of magnitude (from
0.1 Angstrom up to 10^3 Angstrom). Sometimes, the so-called Gaussian-Schell
model, that is widely used in statistical optics in the description of
partially-coherent sources, is applied as an alternative to the
quasi-homogeneous model. However, as we will demonstrate, this model fails to
properly describe coherent properties of X-ray beams from non-homogeneous
undulator sources. As a result, a more rigorous analysis is required. We
propose a technique, based on statistical optics and Fourier optics, to
explicitly calculate the cross-spectral density of an undulator source in the
most general case, at any position after the undulator. Our theory, that makes
consistent use of dimensionless analysis, allows relatively easy treatment and
physical understanding of many asymptotes of the parameter space, together with
their region of applicability. Particular emphasis is given to the asymptotic
situation when the horizontal emittance is much larger than the radiation
wavelength, and the vertical emittance is arbitrary. This case is practically
relevant for third generation synchrotron radiation sources.


title: Homotopy theory of Spectral categories

abstract:
  We construct a Quillen model structure on the category of spectral
categories, where the weak equivalences are the symmetric spectra analogue of
the notion of equivalence of categories.


title: When are Extreme Events the better predictable, the larger they are?

abstract:
  We investigate the predictability of extreme events in time series. The focus
of this work is to understand under which circumstances large events are better
predictable than smaller events. Therefore we use a simple prediction algorithm
based on precursory structures which are identified using the maximum
likelihood principle. Using the receiver operator characteristic curve as a
measure for the quality of predictions we find that the dependence on the event
magnitude is closely linked to the probability distribution function of the
underlying stochastic process. We evaluate this dependence on the probability
distribution function analytically and numerically. If we assume that the
optimal precursory structures are used to make the predictions, we find that
large increments are better predictable if the underlying stochastic process
has a Gaussian probability distribution function, whereas larger increments are
harder to predict if the underlying probability distribution function has a
power law tail. In the case of an exponential distribution function we find no
significant dependence on the event magnitude. Furthermore we compare these
results with predictions of increments in correlated data, namely, velocity
increments of a free jet flow. The velocity increments in the free jet flow are
in dependence on the time scale either asymptotically Gaussian or
asymptotically exponential distributed. The numerical results for predictions
within free jet data are in good agreement with the previous analytical
considerations for random numbers.


title: Pseudo-redundant vacuum energy

abstract:
  We discuss models that can account for today's dark energy. The underlying
cosmological constant may be Planck scale but starts as a redundant coupling
which can be eliminated by a field redefinition. The observed vacuum energy
arises when the redundancy is explicitly broken, say by a non-minimal coupling
to curvature. We give a recipe for constructing models, including R + 1/R type
models, that realize this mechanism and satisfy all solar system constraints on
gravity. A similar model, based on Gauss-Bonnet gravity, provides a technically
natural explanation for dark energy and exhibits an interesting see-saw
behavior: a large underlying cosmological constant gives rise to both low and
high curvature solutions. Such models could be statistically favored in the
string landscape.


title: Elastic Form Factors of $^{3,4}$He up to Large $Q^2$

abstract:
  Elastic electron scattering off $^3$He and $^4$He has recently been studied
at forward and backward scattering angles in Hall A at JLab. The results will
provide accurate data on the elastic form factors, charge and magnetic for
$^3$He and charge only for $^4$He, up to squared momentum transfer $Q^2$-values
of 3.2 GeV$^2$.


title:
Slave-boson based configuration-interaction approach for the Hubbard
  model

abstract:
  Based on the Kotliar-Ruckenstein slave-boson scheme we develop a
configuration-interaction (CI) approach which is suitable to improve the energy
of symmetry-broken saddle-point solutions. The theory is applied to
spin-polaron states in the Hubbard model and compared with analogous results
obtained within the Hartree-Fock approximation. In addition we show that within
the infinite ${\cal D}$ prescription of the Gutzwiller method a CI approach
does not improve the variational result since in the thermodynamic limit matrix
elements between different inhomogeneous states vanish due to an 'orthogonality
catastrophe'.


title: The dark energy equation of state

abstract:
  We perform a study of cosmic evolution with an equation of state parameter
$\omega(t)=\omega_0+\omega_1(t\dot H/H)$ by selecting a phenomenological
$\Lambda$ model of the form, $\dot\Lambda\sim H^3$. This simple proposition
explains both linearly expanding and inflationary Universes with a single set
of equations. We notice that the inflation leads to a scaling in the equation
of state parameter, $\omega(t)$, and hence in equation of state. In this
approach, one of its two parameters have been pin pointed and the other have
been delineated. It has been possible to show a connection between dark energy
and Higgs-Boson.


title: H-alpha observations of zeta Tauri

abstract:
  We report H-alpha observations of zeta Tauri, taken between late 2000 and
early 2006. Next to extending existing long-term montioring of the disk state
of this star we report an intermediate timescale of about 69 days to be present
in the V/R variations of the Halpha line. The observational data will be
published together with this manuscript.