title: Charge and Spin Transport in the One-dimensional Hubbard Model

abstract:
  In this paper we study the charge and spin currents transported by the
elementary excitations of the one-dimensional Hubbard model. The corresponding
current spectra are obtained by both analytic methods and numerical solution of
the Bethe-ansatz equations. For the case of half-filling, we find that the
spin-triplet excitations carry spin but no charge, while charge $\eta$-spin
triplet excitations carry charge but no spin, and both spin-singlet and charge
$\eta$-spin-singlet excitations carry neither spin nor charge currents.


title: On two pictures in the heuristic approach to gravity

abstract:
  We examine the heuristic approach to constant gravitational field by Dehnen,
H\"onl and Westpfahl, extending it everywhere beyond linear approximation. Then
it becomes flexible to accommodate possible modifications of General
Relativity. We have found that two pictures introduced in the related paper by
Thirring are helpful in better understanding some features of gravitation. In
particular, this approach suggest that the privileged system for constant
gravitational field must be the isotropic one and that the requirement of gauge
invariance in gravitation theory may be a luxury; it is sufficient to take care
that the nonphysical degrees of freedom do not invalidate calculations. It
follows from this approach that gravitational constant should depend on
gravitational field and some universality in the form of metric of an
asymmetric body is suggested.


title: Comment on the history of the stretched exponential function

abstract:
  The original article of Rudolf Kohlrausch (1854) on stretched exponentials
and their application to describe relaxation phenomena has been often misquoted
in the literature after its rediscovery around 1984. We discuss here this fact
and attempt to set the record straight.


title: X-ray and optical followup of gamma-ray (up to TeV) sources

abstract:
  The imaging capabilities of the INTEGRAL and HESS observatories allow the
study of hard X-ray and TeV sources with unprecedented positional accuracy.
Here I review the multiwavelength followup studies which are currently being
performed on the unidentified sources detected by these facilities in order to
unveil their actual nature.


title:
Spitzer-IRS high resolution spectroscopy of the 12\mu m Seyfert
  galaxies: I. First results

abstract:
  The first high resolution Spitzer IRS 9-37um spectra of 29 Seyfert galaxies
(about one quarter) of the 12um Active Galaxy Sample are presented and
discussed. The high resolution spectroscopy was obtained with corresponding
off-source observations. This allows excellent background subtraction, so that
the continuum levels and strengths of weak emission lines are accurately
measured. The result is several new combinations of emission line ratios,
line/continuum and continuum/continuum ratios that turn out to be effective
diagnostics of the strength of the AGN component in the IR emission of these
galaxies. The line ratios [NeV]/[NeII], [OIV]/[NeII], already known, but also
[NeIII]/[NeII] and [NeV]/[SiII] can all be effectively used to measure the
dominance of the AGN. We extend the analysis, already done using the 6.2um PAH
emission feature, to the equivalent width of the 11.25um PAH feature, which
also anti-correlates with the dominance of the AGN. We measure that the 11.25um
PAH feature has a constant ratio with the H_2 S(1) irrespective of Seyfert
type, approximately 10 to 1. Using the ratio of accurate flux measurements at
about 19um with the two spectrometer channels, having aperture areas differing
by a factor 4, we measured the source extendness and correlated it with the
emission line and PAH feature equivalent widths. The extendness of the source
gives another measure of the AGN dominance and correlates both with the EWs of
[NeII] and PAH emission. Using the rotational transitions of H$_2$ we were able
to estimate temperatures (200-300K) and masses (1-10 x 10^6 M_sun), or
significant limits on them, for the warm molecular component in the galaxies
observed.


title:
Characterization of researchers in condensed matter physics using simple
  quantity based on h-index

abstract:
  Analysis of citation records of 52 active and productive condensed matter
physicists shows that the ratio of h-index to the mean age of h most highly
cited publications is a reliable quantity that allows meaningful comparison of
scientists of different age.


title:
HST/WFPC2 imaging of the circumnuclear structure of LLAGNs. I Data and
  nuclear morphology

abstract:
  To advance our knowledge of the nature of the central source in LLAGNs and
its relation with stellar clusters, we are carrying out several imaging
projects with HST at near-UV, optical and near-IR wavelengths. In this paper,
we present the first results obtained with observations of the central regions
of 57 LLAGNs imaged with the WFPC2 through any of the V (F555W, F547M, F614W)
and I (F791W, F814W) filters that are available in the HST archive. The sample
contains 34% of the LINERs and 36% of the TOs in the Palomar sample. The mean
spatial resolution of these images is 10 pc. With these data we have built an
atlas that includes structural maps for all the galaxies, useful to identify
compact nuclear sources and, additionally, to characterize the circumnuclear
environment of LLAGNs, determining the frequency of dust and its morphology.
The main results obtained are: 1) We have not found any correlation between the
presence of nuclear compact sources and emission-line type. Thus, nucleated
LINERs are as frequent as nucleated TOs. 2) The nuclei of "Young-TOs" are
brighter than the nuclei of "Old-TOs" and LINERs. These results confirm our
previous results that Young-TOs are separated from other LLAGNs classes in
terms of their central stellar population properties and brightness. 3)
Circumnuclear dust is detected in 88% of the LLAGNs, being almost ubiquitous in
TOs. 4) The dust morphology is complex and varied, from nuclear spiral lanes to
chaotic filaments and nuclear disk-like structures. Chaotic filaments are as
frequent as dust spirals; but nuclear disks are mainly seen in LINERs. These
results suggest an evolutionary sequence of the dust in LLAGNs, LINERs being
the more evolved systems and Young-TOs the youngest. The full collection of
figures are at http://www.iaa.es/~rosa/research/LLAGNs2007/LLAGNs-HSTIma1.html


title:
Measurements of e+e- -> K+K-eta, K+K-pi0 and KsK+pi- Cross Sections
  Using Initial State Radiation Events

abstract:
  This paper reports measurements of processes: e+e- -> gamma KsK+pi-, e+e- ->
gamma K+K-pi0, e+e- -> gamma phi eta, and e+e- -> gamma phi pi0. The initial
state radiated photon allows to cover the hadronic final state in the energy
range from thresholds up to ~4.6 GeV. The overall size of the data sample
analyzed is 232 fb-1, collected by the BaBar detector running at the PEP-II
e+e- storage ring. From the Dalitz plot analysis of the KsK+pi- final state,
moduli and relative phase of the isoscalar and the isovector components of the
e+e- -> K K*(892) cross section are determined. Parameters of phi and rho
recurrences are also measured, using a global fitting procedure which exploits
the interconnection among amplitudes, moduli and phases of the e+e- -> KsK+pi-,
K+K-pi0, phi eta final states. The cross section for the OZI-forbidden process
e+e- -> phi pi0, and the J/psi branching fractions to KK*(892) and K+K-eta are
also measured.


title: f0(1370)

abstract:
  A summary is given of the main sets of data requiring the existence of
f0(1370). Crystal Barrel data on pbar-p -> eta eta pizero contain a visible
f0(1370) peak and require at least a 19 standard deviation contribution. This
alone is sufficient to demonstrate its existence. More extensive data on pbar-p
-> 3pizero at rest contain delicate interferences which determine the mass and
width independently in 1S_0 and 3P_1 annihilation and agree within 5 MeV for
both mass and width. The peak in 2pi is at 1282 +- 5 MeV, but the rapid
increase in 4pi phase space with mass displaces the 4pi peak to 1360 MeV. BES
II data for J/Psi -> phi-pi-\pi contain a visible f0(1370) -> 2pi signal >8
sigma. In all cases, a resonant phase variation is required.


title: Non-rational configurations, polytopes, and surfaces

abstract:
  It is an amazing and a bit counter-intuitive discovery by Micha Perles from
the sixties that there are ``non-rational polytopes'': combinatorial types of
convex polytopes that cannot be realized with rational vertex coordinates.
  We describe a simple construction of non-rational polytopes that does not
need duality (Perles' ``Gale diagrams''): It starts from a non-rational point
configuration in the plane, and proceeds with so-called Lawrence extensions.
  We also show that there are non-rational polyhedral surfaces in 3-space, a
discovery by Ulrich Brehm from 1997. His construction also starts from any
non-rational point configuration in the plane, and then performs what one
should call Brehm extensions, in order to obtain non-rational partial surfaces.
  These examples and objects are first mile stones on the way to the remarkable
"universality theorems'' for polytopes and for polyhedral surfaces by Mn\"ev
(1986), Richter-Gebert (1994), and Brehm (1997).


title: Hadron spectrum of QCD with one quark flavor

abstract:
  The hadron spectrum of one flavor QCD is studied by Monte Carlo simulations.
The Symanzik tree-level-improved Wilson action is used for the gauge field and
the Wilson action for the fermion. The theory is simulated by a polynomial
hybrid Monte Carlo algorithm (PHMC). The mass spectrum of hadronic bound states
is investigated at two different lattice spacings: a ~ 0.37r_0 and a ~ 0.27r_0,
corresponding to ~0.19fm and ~0.13fm in ordinary QCD. The lattice extension is
fixed to L ~ 4.4r_0 (~2.2fm). The lightest simulated quark mass corresponds to
a pion with mass ~270MeV. Properties of the theory are analyzed by making use
of the ideas of partially quenched chiral perturbation theory (PQChPT). The
symmetry of the single flavor theory can be artificially enhanced by adding
extra valence quarks, which can be interpreted as u and d quarks. Operators in
the valence pion sector can be built. Masses and decay constants are analyzed
by using PQChPT formulae at next-to-leading order.


title:
Phase-Coherent Dynamics of a Superconducting Flux Qubit with
  Capacitive-Bias Readout

abstract:
  We present a systematic study of the phase-coherent dynamics of a
superconducting three-Josephson-junction flux qubit. The qubit state is
detected with the integrated-pulse method, which is a variant of the pulsed
switching DC SQUID method. In this scheme the DC SQUID bias current pulse is
applied via a capacitor instead of a resistor, giving rise to a narrow
band-pass instead of a pure low-pass filter configuration of the
electromagnetic environment. Measuring one and the same qubit with both setups
allows a direct comparison. With the capacitive method about four times faster
switching pulses and an increased visibility are achieved. Furthermore, the
deliberate engineering of the electromagnetic environment, which minimizes the
noise due to the bias circuit, is facilitated. Right at the degeneracy point
the qubit coherence is limited by energy relaxation. We find two main noise
contributions. White noise is limiting the energy relaxation and contributing
to the dephasing far from the degeneracy point. 1/f-noise is the dominant
source of dephasing in the direct vicinity of the optimal point. The influence
of 1/f-noise is also supported by non-random beatings in the Ramsey and spin
echo decay traces. Numeric simulations of a coupled qubit-oscillator system
indicate that these beatings are due to the resonant interaction of the qubit
with at least one point-like fluctuator, coupled especially strongly to the
qubit.


title: Cusps in K_L --> 3 pi decays

abstract:
  The pion mass difference generates a pronounced cusp in K --> 3 pi decays,
the strength of which is related to the pi pi S-wave scattering lengths. We
apply an effective field theory framework developed earlier to evaluate the
amplitudes for K_L --> 3 pi decays in a systematic manner, where the strictures
imposed by analyticity and unitarity are respected automatically. The
amplitudes for the decay eta --> 3 pi are also given.


title: Faster than light in a birefringent crystal

abstract:
  We examine the effect of superluminal signal propagation through a
birefringent crystal, where the effect is not due to absorption or reflection,
but to the filtration of a special polarization component. We first examine the
effect by a stationary phase analysis, with results consistent with those of an
earlier analysis of the system. We supplement this analysis by considering the
transit of a gaussian wave and find bounds for the validity of the stationary
phase result. The propagation of the gaussian wave is illustrated by figures.


title: Residues of Correlators in the Strongly Coupled N=4 Plasma

abstract:
  Quasinormal modes of asymptotically AdS black holes can be interpreted as
poles of retarded correlators in the dual gauge theory. To determine the
response of the system to small external perturbations it is not enough to know
the location of the poles: one also needs to know the residues. We compute them
for R-charge currents and find that they are complex except for the
hydrodynamic mode, whose residue is purely imaginary. For different quasinormal
modes the residue grows with momentum q, whereas for the hydrodynamic mode it
behaves as a damped oscillation with distinct zeroes at finite q. Similar to
collective excitations at weak coupling the hydrodynamic mode decouples at
short wavelengths. Knowledge of the residues allows as well to define the time
scale t_H from when on the system enters the hydrodynamic regime, restricting
the validity of hydrodynamic simulations to times t>t_H.


title: Causality and Association: The Statistical and Legal Approaches

abstract:
  This paper discusses different needs and approaches to establishing
``causation'' that are relevant in legal cases involving statistical input
based on epidemiological (or more generally observational or population-based)
information. We distinguish between three versions of ``cause'': the first
involves negligence in providing or allowing exposure, the second involves
``cause'' as it is shown through a scientifically proved increased risk of an
outcome from the exposure in a population, and the third considers ``cause'' as
it might apply to an individual plaintiff based on the first two. The
population-oriented ``cause'' is that commonly addressed by statisticians, and
we propose a variation on the Bradford Hill approach to testing such causality
in an observational framework, and discuss how such a systematic series of
tests might be considered in a legal context. We review some current legal
approaches to using probabilistic statements, and link these with the
scientific methodology as developed here. In particular, we provide an approach
both to the idea of individual outcomes being caused on a balance of
probabilities, and to the idea of material contribution to such outcomes.
Statistical terminology and legal usage of terms such as ``proof on the balance
of probabilities'' or ``causation'' can easily become confused, largely due to
similar language describing dissimilar concepts; we conclude, however, that a
careful analysis can identify and separate those areas in which a legal
decision alone is required and those areas in which scientific approaches are
useful.


title: C^{1/2}P^{1/2}T^{1/2} Symmetry of the Chaotic Inflation Dynamics

abstract:
  In this work is shown that standard dynamical equations of the chaotic
inflation for a massive real scalar field hold an especial local gauge
symmetry. Given symmetry admits that inflation field mass can be considered as
an especial "charge". Also, it is shown that given equations except expected
$CPT$ symmetry, hold surprisingly, $C^{{1/2}}P^{{1/2}}T^{{1/2}}$ symmetry too.


title: Associated production of a Z boson and a b-jet in ATLAS

abstract:
  The current uncertainty on the parametrization of the partonic content of the
proton (PDF's) affects the potential for the discovery of new physics at LHC.
The study of Z boson production in association with a b-jet can considerably
reduce such uncertainty. In addition, this process represents a background both
to the search for the Higgs boson and for SUSY particles. We present an update,
based on the full simulation data sample produced for the Rome Physics
Workshop, of a preliminary study in the case where the Z boson decays in mu+
mu-.


title:
Chemical potential shift induced by double-exchange and polaronic
  effects in Nd_{1-x}Sr_xMnO_3

abstract:
  We have studied the chemical potential shift as a function of temperature in
Nd$_{1-x}$Sr$_x$MnO$_3$ (NSMO) by measurements of core-level photoemission
spectra. For ferromagnetic samples ($x=0.4$ and 0.45), we observed an unusually
large upward chemical potential shift with decreasing temperature in the
low-temperature region of the ferromagnetic metallic (FM) phase. This can be
explained by the double-exchange (DE) mechanism if the $e_g$ band is split by
dynamical/local Jahn-Teller effect. The shift was suppressed near the Curie
temperature ($T_C$), which we attribute to the crossover from the DE to
lattice-polaron regimes.


title:
How Sensitive are Di-Leptons from Rho Mesons to the High Baryon Density
  Region?

abstract:
  We show that the measurement of di-leptons might provide only a restricted
view into the most dense stages of heavy ion reactions. Thus, possible studies
of meson and baryon properties at high baryon densities, as e.g. done at
GSI-HADES and envisioned for FAIR-CBM, might observe weaker effects than
currently expected in certain approaches. We argue that the strong absorption
of resonances in the high baryon density region of the heavy ion collision
masks information from the early hot and dense phase due to a strong increase
of the total decay width because of collisional broadening. To obtain
additional information, we also compare the currently used approaches to
extract di-leptons from transport simulations - i.e. shining, only vector
mesons from final baryon resonance decays and instant emission of di-leptons
and find a strong sensitivity on the method employed in particular at FAIR and
SPS energies. It is shown explicitly that a restriction to rho meson (and
therefore di-lepton) production only in final state baryon resonance decays
provide a strong bias towards rather low baryon densities. The results
presented are obtained from UrQMD v2.3 calculations using the standard set-up.


title:
Composantes irr\'eductibles de la vari\'et\'e commutante nilpotente
  d'une alg\`ebre de Lie sym\'etrique semi-simple

abstract:
  Let \theta be an involution of the semisimple Lie algebra g and g=k+p be the
associated Cartan decomposition. The nilpotent commuting variety of (g,\theta)
consists in pairs of nilpotent elements (x,y) of p such that [x,y]=0. It is
conjectured that this variety is equidimensional and that its irreducible
components are indexed by the orbits of p-distinguished elements. This
conjecture was established by A. Premet in the case (g \times g, \theta) where
\theta(x,y)=(y,x). In this work we prove the conjecture in a significant number
of other cases.


title:
Neutron star spin-kick velocity correlation effect on binary neutron
  star coalescence rates and spin-orbit misalignment of the components

abstract:
  We study the effect of the neutron star spin -- kick velocity alignment
observed in young radio pulsars on the coalescence rate of binary neutron
stars. Two scenarios of the neutron star formation are considered: when the
kick is always present and when it is small or absent if a neutron star is
formed in a binary system due to electron-capture degenerate core collapse. The
effect is shown to be especially strong for large kick amplitudes and tight
alignments, reducing the expected galactic rate of binary neutron star
coalescences compared to calculations with randomly directed kicks. The
spin-kick correlation also leads to a much narrower NS spin-orbit misalignment.


title:
LASSO, Iterative Feature Selection and the Correlation Selector: Oracle
  Inequalities and Numerical Performances

abstract:
  We propose a general family of algorithms for regression estimation with
quadratic loss. Our algorithms are able to select relevant functions into a
large dictionary. We prove that a lot of algorithms that have already been
studied for this task (LASSO and Group LASSO, Dantzig selector, Iterative
Feature Selection, among others) belong to our family, and exhibit another
particular member of this family that we call Correlation Selector in this
paper. Using general properties of our family of algorithm we prove oracle
inequalities for IFS, for the LASSO and for the Correlation Selector, and
compare numerical performances of these estimators on a toy example.


title: Nuclear effects in Neutrino Nuclear Cross-sections

abstract:
  Nuclear effects in the quasielastic and inelastic scattering of
neutrinos(antineutrinos) from nuclear targets have been studied. The
calculations are done in the local density approximation which take into
account the effect of nucleon motion as well as renormalisation of weak
transition strengths in the nuclear medium. The inelastic reaction leading to
production of pions is calculated in a $\Delta$ dominance model taking into
account the renormalization of $\Delta$ properties in the nuclear medium.


title:
Dust mass-loss rates from AGB stars in the Fornax and Sagittarius dwarf
  Spheroidal galaxies

abstract:
  To study the effect of metallicity on the mass-loss rate of asymptotic giant
branch (AGB) stars, we have conducted mid-infrared photometric measurements of
such stars in the Sagittarius (Sgr dSph) and Fornax dwarf spheroidal galaxies
with the 10-$\mu$m camera VISIR at the VLT. We derive mass-loss rates for 29
AGB stars in Sgr dSph and 2 in Fornax. The dust mass-loss rates are estimated
from the $K-[9]$ and $K-[11]$ colours. Radiative transfer models are used to
check the consistency of the method. Published IRAS and Spitzer data confirm
that the same tight correlation between $K-[12]$ colour and dust mass-loss
rates is observed for AGB stars from galaxies with different metallicities,
i.e. the Galaxy, the LMC and the SMC.
  The derived dust mass-loss rates are in the range 5$\times10^{-10}$ to
3$\times10^{-8}$ M$_{\odot}$yr$^{-1}$ for the observed AGB stars in Sgr dSph
and around 5$\times10^{-9}$ M$_{\odot}$yr$^{-1}$ for those in Fornax; while
values obtained with the two different methods are of the same order of
magnitude. The mass-loss rates for these stars are higher than the nuclear
burning rates, so they will terminate their AGB phase by the depletion of their
stellar mantles before their core can grow significantly. Some observed stars
have lower mass-loss rates than the minimum value predicted by theoretical
models.


title: Theta vacuum physics from QCD at fixed topology

abstract:
  We propose a method to obtain physical quantities in the theta vacuum from
those at fixed topology, which are different by finite size effects. Extending
the work by Brower et al., we derive the formula to estimate these finite size
corrections for arbitrary correlators in terms of the topological
susceptibility and the theta dependence. Applying this formula, we show that
topological susceptibility can be measured through two-point functions of
pseudoscalar operator.


title:
Measurement of the K_L \to \pi\mu\nu form factor parameters with the
  KLOE detector

abstract:
  Using 328 pb^{-1}of data collected at DAFNE corresponding to $\sim$ 1.8
million $K_L\to \pi\mu\nu$ decays, we have measured the $K_{\mu 3}$ form factor
parameters. The structure of the $K-\pi$ vector-current provides information
about the dynamics of the strong interaction; its knowledge is necessary for
evaluation of the phase-space integral required for measuring the CKM matrix
element $V_{us}$ and for testing lepton universality in kaon decays. Using a
new parametrization for the vector and scalar form factors, we find
$\lambda_+$=\pt(25.7\pm 0.6),-3, and $\lambda_0$=\pt(14.0\pm 2.1),-3,. Our
result for $\lambda_0$, together with recent lattice calculations of $f_\pi$,
$f_K$ and $f(0)$, satisfies the Callan-Trieman relation


title: Holographic flavor in theories with eight supercharges

abstract:
  We review the holographic duals of gauge theories with eight supercharges
obtained by adding very few flavors to pure supersymmetric Yang-Mills with
sixteen supercharges. Assuming a brane-probe limit, the gravity duals are
engineered in terms of probe branes (the so-called flavor brane) in the
background of the color branes. Both types of branes intersect on a given
subspace in which the matter is confined. The gauge theory dual is thus the
corresponding flavoring of the gauge theory with sixteen supercharges. Those
theories have in general a non-trivial phase structure; which is also captured
in a beautiful way by the gravity dual. Along the lines of the gauge/gravity
duality, we review also some of the results on the meson spectrum in the
different phases of the theories.


title: Critical behavior of random spin systems

abstract:
  We provide a strategy to find in few elementary calculations the critical
exponents of the overlaps for dilute spin glasses, in absence of external
field. Such a strategy is based on the expansion of a suitably perturbed
average of the overlaps, which is used in the formulation of the free energy as
the difference between a cavity part and the derivative of the free energy
itself, considered as a function of the connectivity of the model. We assume
the validity of certain reasonable approximations, e.g. that higher powers of
overlap monomials are of smaller magnitude near the critical point, of which we
do not provide a rigorous proof.


title: Geothermal Casimir Phenomena

abstract:
  We present first worldline analytical and numerical results for the
nontrivial interplay between geometry and temperature dependencies of the
Casimir effect. We show that the temperature dependence of the Casimir force
can be significantly larger for open geometries (e.g., perpendicular plates)
than for closed geometries (e.g., parallel plates). For surface separations in
the experimentally relevant range, the thermal correction for the
perpendicular-plates configuration exhibits a stronger parameter dependence and
exceeds that for parallel plates by an order of magnitude at room temperature.
This effect can be attributed to the fact that the fluctuation spectrum for
closed geometries is gapped, inhibiting the thermal excitation of modes at low
temperatures. By contrast, open geometries support a thermal excitation of the
low-lying modes in the gapless spectrum already at low temperatures.


title:
Exotic solutions in General Relativity: Traversable wormholes and 'warp
  drive' spacetimes

abstract:
  The General Theory of Relativity has been an extremely successful theory,
with a well established experimental footing, at least for weak gravitational
fields. Its predictions range from the existence of black holes, gravitational
radiation to the cosmological models, predicting a primordial beginning, namely
the big-bang. All these solutions have been obtained by first considering a
plausible distribution of matter, and through the Einstein field equation, the
spacetime metric of the geometry is determined. However, one may solve the
Einstein field equation in the reverse direction, namely, one first considers
an interesting and exotic spacetime metric, then finds the matter source
responsible for the respective geometry. In this manner, it was found that some
of these solutions possess a peculiar property, namely 'exotic matter,'
involving a stress-energy tensor that violates the null energy condition. These
geometries also allow closed timelike curves, with the respective causality
violations. These solutions are primarily useful as 'gedanken-experiments' and
as a theoretician's probe of the foundations of general relativity, and include
traversable wormholes and superluminal 'warp drive' spacetimes. Thus, one may
be tempted to denote these geometries as 'exotic' solutions of the Einstein
field equation, as they violate the energy conditions and generate closed
timelike curves. In this article, in addition to extensively exploring
interesting features, in particular, the physical properties and
characteristics of these 'exotic spacetimes,' we also analyze other non-trivial
general relativistic geometries which generate closed timelike curves.


title: Twist solitons in complex macromolecules: from DNA to polyethylene

abstract:
  DNA torsion dynamics is essential in the transcription process; simple models
for it have been proposed by several authors, in particular Yakushevich (Y
model). These are strongly related to models of DNA separation dynamics such as
the one first proposed by Peyrard and Bishop (and developed by Dauxois, Barbi,
Cocco and Monasson among others), but support topological solitons. We recently
developed a ``composite'' version of the Y model, in which the sugar-phosphate
group and the base are described by separate degrees of freedom. This at the
same time fits experimental data better than the simple Y model, and shows
dynamical phenomena, which are of interest beyond DNA dynamics. Of particular
relevance are the mechanism for selecting the speed of solitons by tuning the
physical parameters of the non linear medium and the hierarchal separation of
the relevant degrees of freedom in ``master'' and ``slave''. These mechanisms
apply not only do DNA, but also to more general macromolecules, as we show
concretely by considering polyethylene.


title: Dynamical freeze-out condition in ultrarelativistic heavy ion collisions

abstract:
  We determine the decoupling surfaces for the hydrodynamic description of
heavy ion collisions at RHIC and LHC by comparing the local hydrodynamic
expansion rate with the microscopic pion-pion scattering rate. The pion $p_T$
spectra for nuclear collisions at RHIC and LHC are computed by applying the
Cooper-Frye procedure on the dynamical-decoupling surfaces, and compared with
those obtained from the constant-temperature freeze-out surfaces. Comparison
with RHIC data shows that the system indeed decouples when the expansion rate
becomes comparable with the pion scattering rate. The dynamical decoupling
based on the rates comparison also suggests that the effective decoupling
temperature in central heavy ion collisions remains practically unchanged from
RHIC to LHC.


title: Homomorphisms and Structural Properties of Relational Systems

abstract:
  Two main topics are considered: The characterisation of finite homomorphism
dualities for relational structures, and the splitting property of maximal
antichains in the homomorphism order.


title: Innerness of Derivations on Subalgebras of Measurable Operators

abstract:
  Given a von Neumann algebra $M$ with a faithful normal semi-finite trace
$\tau,$ let $L(M, \tau)$ be the algebra of all $\tau$-measurable operators
affiliated with $M.$ We prove that if $A$ is a locally convex reflexive
complete metrizable solid $\ast$-subalgebra in $L(M, \tau),$ which can be
embedded into a locally bounded weak Fr\'{e}chet $M$-bimodule, then any
derivation on $A$ is inner.


title:
Meson distribution amplitudes - applications to weak radiative B decays
  and B transition form factors

abstract:
  This thesis examines the applications and determinations of meson light-cone
distribution amplitudes. The investigation of such processes, in the context of
$B$ physics, provides one with a rich and extensive way of determining the
Standard Model parameters of the CKM matrix, which are essential in describing
CP violation, and searching for tell-tale signs of new physics beyond the
Standard Model. We investigate the twist-2 and twist-3 distribution amplitudes
of light vector mesons and fully examine $\rm SU(3)_F$-breaking effects and
include leading G-parity violating terms. Numerical values of the leading
non-perturbative hadronic parameters are determined from QCD sum rules. The
distribution amplitude results find direct application in the radiative $B$
decays to light vector mesons $B \to V \gamma$. We examine the
phenomenologically most important observables in this decay mode using the
formalism of QCD factorisation. We also include long-distance photon emission
and soft quark loop effects, which formally lie outside the QCD factorisation
formalism. The analysis encompasses all the modes $B_{u,d} \to \rho, \omega,
K^*$ and $B_{s} \to \phi, \bar{K}^*$. We also calculate the $B \to \etapb$
transition form factor using QCD sum rules on the light-cone. We include the
singlet contribution originating from the $\rm U(1)_A$ anomaly and bring the
calculation consistently within the $\eta$-$\etap$ mixing framework.


title: Criterion of multi-switching stability for magnetic nanoparticles

abstract:
  We present a procedure to study the switching and the stability of an array
of magnetic nanoparticles in the dynamical regime. The procedure leads to the
criterion of multi-switching stability to be satisfied in order to have stable
switching. The criterion is used to compare various magnetic-field-induced
switching schemes, either present in the literature or suggested in the present
work. In particular, we perform micromagnetic simulations to study the
magnetization trajectories and the stability of the magnetization after
switching for nanoparticles of elliptical shape. We evaluate the stability of
the switching as a function of the thickness of the particles and the rise and
fall times of the magnetic pulses, both at zero and room temperature.
Furthermore, we investigate the role of the dipolar interaction and its
influence on the various switching schemes. We find that the criterion of
multi-switching stability can be satisfied at room temperature and in the
presence of dipolar interactions for pulses shaped according to CMOS
specifications, for switching rates in the GHz regime.


title: Structure Learning in Nested Effects Models

abstract:
  Nested Effects Models (NEMs) are a class of graphical models introduced to
analyze the results of gene perturbation screens. NEMs explore noisy subset
relations between the high-dimensional outputs of phenotyping studies, e.g. the
effects showing in gene expression profiles or as morphological features of the
perturbed cell.
  In this paper we expand the statistical basis of NEMs in four directions:
First, we derive a new formula for the likelihood function of a NEM, which
generalizes previous results for binary data. Second, we prove model
identifiability under mild assumptions. Third, we show that the new formulation
of the likelihood allows to efficiently traverse model space. Fourth, we
incorporate prior knowledge and an automated variable selection criterion to
decrease the influence of noise in the data.


title: Robust Machine Learning Applied to Terascale Astronomical Datasets

abstract:
  We present recent results from the Laboratory for Cosmological Data Mining
(http://lcdm.astro.uiuc.edu) at the National Center for Supercomputing
Applications (NCSA) to provide robust classifications and photometric redshifts
for objects in the terascale-class Sloan Digital Sky Survey (SDSS). Through a
combination of machine learning in the form of decision trees, k-nearest
neighbor, and genetic algorithms, the use of supercomputing resources at NCSA,
and the cyberenvironment Data-to-Knowledge, we are able to provide improved
classifications for over 100 million objects in the SDSS, improved photometric
redshifts, and a full exploitation of the powerful k-nearest neighbor
algorithm. This work is the first to apply the full power of these algorithms
to contemporary terascale astronomical datasets, and the improvement over
existing results is demonstrable. We discuss issues that we have encountered in
dealing with data on the terascale, and possible solutions that can be
implemented to deal with upcoming petascale datasets.


title:
Correction to "The divergence of Banach space valued random variables on
  Wiener space", Prob. Th. Rel. Fields 132, 291-320 (2005)

abstract:
  As a result of some mistakes discovered in the paper mentioned in the title,
Corollaries 3.5 and 3.17a) are withdrawn and a new proof is provided for
Proposition 3.14, under the added assumption that the second dual of the
underlying Banach space Y possesses the Radon-Nykodim property.


title: Homogeneous Poisson structures on symmetric spaces

abstract:
  We calculate, in a relatively explicit way, the Hamiltonian systems which
arise from the Evens-Lu construction of homogeneous Poisson structures on both
compact and noncompact type symmetric spaces. A corollary is that the
Hamiltonian system arising in the noncompact case is isomorphic to the generic
Hamiltonian system arising in the compact case. In the group case these systems
are also isomorphic to those arising from the Bruhat Poisson structure on the
flag space, and hence, by results of Lu, can be completely factored.


title: Escape from the vicinity of fractal basin boundaries of a star cluster

abstract:
  The dissolution process of star clusters is rather intricate for theory. We
investigate it in the context of chaotic dynamics. We use the simple Plummer
model for the gravitational field of a star cluster and treat the tidal field
of the Galaxy within the tidal approximation. That is, a linear approximation
of tidal forces from the Galaxy based on epicyclic theory in a rotating
reference frame. The Poincar\'e surfaces of section reveal the effect of a
Coriolis asymmetry. The system is non-hyperbolic which has important
consequences for the dynamics. We calculated the basins of escape with respect
to the Lagrangian points $L_1$ and $L_2$. The longest escape times have been
measured for initial conditions in the vicinity of the fractal basin
boundaries. Furthermore, we computed the chaotic saddle for the system and its
stable and unstable manifolds. The chaotic saddle is a fractal structure in
phase space which has the form of a Cantor set and introduces chaos into the
system.


title: Non-linear estimation is easy

abstract:
  Non-linear state estimation and some related topics, like parametric
estimation, fault diagnosis, and perturbation attenuation, are tackled here via
a new methodology in numerical differentiation. The corresponding basic system
theoretic definitions and properties are presented within the framework of
differential algebra, which permits to handle system variables and their
derivatives of any order. Several academic examples and their computer
simulations, with on-line estimations, are illustrating our viewpoint.

categories: cs.CE cs.NA cs.PF math.AC math.NA math.OC


title:
Energy spectrum of electromagnetic normal modes in dissipative media:
  modes between two metal half spaces

abstract:
  The energy spectrum of the electromagnetic normal modes plays a central role
in the theory of the van der Waals and Casimir interaction. In dissipative
media it appears as if there are distinct normal modes with complex valued
energies. The summation of the zero-point energies of these modes render a
complex valued result. Using the contour integration, resulting from the use of
the generalized argument principle, gives a real valued and different result.
We resolve this contradiction and show that the spectrum of true normal modes
form a continuum with real frequencies. We illustrate the problem in connection
with the van der Waals interaction between two metal half spaces.


title:
Self-Consistent Models of the AGN and Black Hole Populations: Duty
  Cycles, Accretion Rates, and the Mean Radiative Efficiency

abstract:
  We construct evolutionary models of the populations of AGN and supermassive
black holes, in which the black hole mass function grows at the rate implied by
the observed luminosity function, given assumptions about the radiative
efficiency and the Eddington ratio. We draw on a variety of recent X-ray and
optical measurements to estimate the bolometric AGN luminosity function and
compare to X-ray background data and the independent estimate of Hopkins et al.
(2007) to assess remaining systematic uncertainties. The integrated AGN
emissivity closely tracks the cosmic star formation history, suggesting that
star formation and black hole growth are closely linked at all redshifts.
Observational uncertainties in the local black hole mass function remain
substantial, with estimates of the integrated black hole mass density \rho_BH
spanning the range 3-5.5x10^5 Msun/Mpc^3. We find good agreement with estimates
of the local mass function for a reference model where all active black holes
have efficiency \eps=0.065 and L_bol/L_Edd~0.4. In this model, the duty cycle
of 10^9 Msun black holes declines from 0.07 at z=3 to 0.004 at z=1 and 0.0001
at z=0. The decline is shallower for less massive black holes, a signature of
"downsizing" evolution in which more massive black holes build their mass
earlier. The predicted duty cycles and AGN clustering bias in this model are in
reasonable accord with observational estimates. If the typical Eddington ratio
declines at z<2, then the "downsizing" of black hole growth is less pronounced.
Matching the integrated AGN emissivity to the local black hole mass density
implies \eps=0.075 (\rho_BH/4.5x10^5 Msun/Mpc^3)^{-1} for our standard
luminosity function estimate (25% higher for Hopkins et al.'s), lower than the
values \eps=0.16-0.20 predicted by MHD simulations of disk accretion.


title: Equidistribution of Dense Subgroups on Nilpotent Lie Groups

abstract:
  Let $\Gamma$ be a dense subgroup of a simply connected nilpotent Lie group
$G$ generated by a finite symmetric set $S$. We consider the $n$-ball $S_n$ for
the word metric induced by $S$ on $\Gamma$. We show that $S_n$ (with uniform
measure) becomes equidistributed on $G$ with respect to the Haar measure as n
tends to infinity. We give rates and also prove the analogous result for random
walk averages (i.e. the local limit theorem).


title:
The emergence of the electrostatic field as a Feynman sum in random
  tilings with holes

abstract:
  We consider random lozenge tilings on the triangular lattice with holes
$Q_1,...,Q_n$ in some fixed position. For each unit triangle not in a hole,
consider the average orientation of the lozenge covering it. We show that the
scaling limit of this discrete field is the electrostatic field obtained when
regarding each hole $Q_i$ as an electrical charge of magnitude equal to the
difference between the number of unit triangles of the two different
orientations inside $Q_i$. This is then restated in terms of random surfaces,
yielding the result that the average over surfaces with prescribed height at
the union of the boundaries of the holes is, in the scaling limit, a sum of
helicoids.

categories: math-ph cond-mat.stat-mech math.CO math.MP


title:
Chaos and plasticity in superconductor vortices: a low-dimensional
  dynamics

abstract:
  We present new results of numerical simulations for driven vortex lattices in
presence of random disorder at zero temperature. We show that the plastic
dynamics of vortices display dissipative chaos. Intermittency "routes to chaos"
have been clearly identified below the differential resistance peak. The peak
region is characterized by positive Lyapunov exponents characteristic of chaos,
and low frequency broad-band noise. Furthermore we find a low fractal dimension
of the strange attractor, which suggests that only a few dynamical variables
are sufficient to model the complex plastic dynamics of vortices.


title:
Global rigidity of holomorphic Riemannian metrics on compact complex
  3-manifolds

abstract:
  We study compact complex 3-manifolds admitting holomorphic Riemannian
metrics. We prove a uniformization result: up to a finite unramified cover,
such a manifold admits a holomorphic Riemannian metric of constant sectionnal
curvature.


title: Transport of strong-coupling polarons in optical lattices

abstract:
  We study the transport of ultracold impurity atoms immersed in a
Bose-Einstein condensate (BEC) and trapped in a tight optical lattice. Within
the strong-coupling regime, we derive an extended Hubbard model describing the
dynamics of the impurities in terms of polarons, i.e. impurities dressed by a
coherent state of Bogoliubov phonons. Using a generalized master equation based
on this microscopic model we show that inelastic and dissipative phonon
scattering results in (i) a crossover from coherent to incoherent transport of
impurities with increasing BEC temperature and (ii) the emergence of a net
atomic current across a tilted optical lattice. The dependence of the atomic
current on the lattice tilt changes from ohmic conductance to negative
differential conductance within an experimentally accessible parameter regime.
This transition is accurately described by an Esaki-Tsu-type relation with the
effective relaxation time of the impurities as a temperature-dependent
parameter.


title: Mean-value property on manifolds with minimal horospheres

abstract:
  Let (M,g) be a non-compact and complete Riemannian manifold with minimal
horospheres and infinite injectivity radius. We prove that bounded functions on
(M,g) satisfying the mean-value property are constant. We extend thus a result
of A. Ranjan and H. Shah who proved a similar result for bounded harmonic
functions on harmonic manifolds with minimal horospheres.


title: The lonely runner with seven runners

abstract:
  Suppose $k+1$ runners having nonzero constant speeds run laps on a
unit-length circular track starting at the same time and place. A runner is
said to be lonely if she is at distance at least $1/(k+1)$ along the track to
every other runner. The lonely runner conjecture states that every runner gets
lonely. The conjecture has been proved up to six runners ($k\le 5$). A
formulation of the problem is related to the regular chromatic number of
distance graphs. We use a new tool developed in this context to solve the first
open case of the conjecture with seven runners.


title: Topological types of 3-dimensional small covers

abstract:
  In this paper we study the (equivariant) topological types of a class of
3-dimensional closed manifolds (i.e., 3-dimensional small covers), each of
which admits a locally standard $(\mathbb{Z}_2)^3$-action such that its orbit
space is a simple convex 3-polytope. We introduce six equivariant operations on
3-dimensional small covers. These six operations are interesting because of
their combinatorial natures. Then we show that each 3-dimensional small cover
can be obtained from $\mathbb{R}P^3$ and $S^1\times\mathbb{R}P^2$ with certain
$(\mathbb{Z}_2)^3$-actions under these six operations. As an application, we
classify all 3-dimensional small covers up to $({\Bbb Z}_2)^3$-equivariant
unoriented cobordism.


title: Curvatures of Smooth and Discrete Surfaces

abstract:
  We discuss notions of Gauss curvature and mean curvature for polyhedral
surfaces. The discretizations are guided by the principle of preserving
integral relations for curvatures, like the Gauss/Bonnet theorem and the
mean-curvature force balance equation.


title:
The Mott metal-insulator transition in the 1D Hubbard model in an
  external magnetic field

abstract:
  We study the low energy behavior of the one dimensional Hubbard model across
the Mott metal-insulator phase transition in an external magnetic field. In
particular we calculate elements of the dressed charge matrix at the critical
point of the Mott transition for arbitrary Hubbard repulsion and magnetization
numerically and, in certain limiting cases, analytically. These results are
combined with a non-perturbative effective field theory approach to reveal how
the breaking of time reversal symmetry influences the Mott transition.


title:
Remarks on Jurdzinski and Lorys' proof that palindromes are not a
  Church-Rosser language

abstract:
  In 2002 Jurdzinski and Lorys settled a long-standing conjecture that
palindromes are not a Church-Rosser language. Their proof required a
sophisticated theory about computation graphs of 2-stack automata. We present
their proof in terms of 1-tape Turing machines.We also provide an alternative
proof of Buntrock and Otto's result that the set of non-square bitstrings,
which is context-free, is not Church-Rosser.


title:
Symmetry classes of spanning trees of Aztec diamonds and perfect
  matchings of odd squares with a unit hole

abstract:
  We say that two graphs are similar if their adjacency matrices are similar
matrices. We show that the square grid $G_n$ of order $n$ is similar to the
disjoint union of two copies of the quartered Aztec diamond $QAD_{n-1}$ of
order $n-1$ with the path $P_n^{(2)}$ on $n$ vertices having edge weights equal
to~2. Our proof is based on an explicit change of basis in the vector space on
which the adjacency matrix acts. The arguments verifying that this change of
basis works are combinatorial. In particular, this allows computing the number
of spanning trees of quartered Aztec diamonds.
  We present and analyze three more families of graphs that share the above
described ``linear squarishness'' property of square grids: odd Aztec diamonds,
mixed Aztec diamonds, and Aztec pillowcases--graphs obtained from two copies of
an Aztec diamond by identifying the corresponding vertices on their convex
hulls.
  We apply the above results to enumerate all the symmetry classes of spanning
trees of the even Aztec diamonds, and all the symmetry classes not involving
rotations of the spanning trees of odd and mixed Aztec diamonds. We also
enumerate all but the base case of the symmetry classes of perfect matchings of
odd square grids with the central vertex removed. In addition, we obtain a
product formula for the number of spanning trees of Aztec pillowcases.


title:
Supersymmetric parameter constraints from isospin asymmetry in b -> s
  gamma transitions

abstract:
  Isospin asymmetry in b -> s gamma transitions provides severe constraints on
new physics parameters, due to the small values of the experimental
measurements. We exploit here this new observable to study different
supersymmetric models. For this purpose, we calculate the isospin symmetry
breaking in the MSSM with minimal flavor violation, considering NLO
contributions. We study three scenarios for supersymmetry breaking, namely
mSUGRA, AMSB and GMSB. In most of the explored regions, we find very
restrictive constraints on the allowed parameters for these models.


title:
Chemical Pressure Tuning of Magnetic Coupling in the La1.4Sr1.6Mn2O7
  Bilayered Manganite

abstract:
  In this paper the effect of the chemical pressure induced by the Sr
replacement for Ca in the La1.4Sr1.6Mn2O7 lattice is directly probed by means
of neutron diffraction as a function of temperature. The results show a
progressive change of the magnetic coupling from ferromagnetic to
antiferromagnetic by increasing the Ca content,. indicating that the orbital
order of the Mn ions is affected in the same way by the application of an
external pressure and by the chemical pressure.


title: SN 2002cv: A Heavily Obscured Type Ia Supernova

abstract:
  We present VRIJHK photometry, and optical and near-infrared spectroscopy, of
the heavily extinguished Type Ia supernova (SN) 2002cv, located in NGC 3190,
which is also the parent galaxy of the Type Ia SN 2002bo. SN 2002cv, not
visible in the blue, has a total visual extinction of 8.74 +- 0.21 mag. In
spite of this we were able to obtain the light curves between -10 and +207 days
from the maximum in the I band, and also to follow the spectral evolution,
deriving its key parameters. We found the peak I-band brightness to be Imax =
16.57 +- 0.10 mag, the maximum absolute I magnitude to be MmaxI = -18.79 +-
0.20, and the parameter dm15(B) specifying the width of the B-band light curve
to be 1.46 +- 0.17 mag. The latter was derived using the relations between this
parameter and dm40(I) and the time interval dtmax(I) between the two maxima in
the I-band light curve. As has been found for previously observed, highly
extinguished SNe Ia, a small value of 1.59 +- 0.07 was obtained here for the
ratio Rv of the total-to-selective extinction ratio for SN 2002cv, which
implies a small mean size for the grains along the line of sight toward us.
Since it was found for SN 2002bo a canonical value of 3.1, here we present a
clear evidence of different dust properties inside NGC 3190.


title:
Centrality evolution of $p_t$ and $y_t$ spectra from Au-Au collisions at
  $\sqrt{s_{NN}} = 200$ GeV

abstract:
  A two-component analysis of spectra to $p_t = 12$ GeV/c for identified pions
and protons from 200 GeV Au-Au collisions is presented. The method is similar
to an analysis of the $n_{ch}$ dependence of $p_t$ spectra from p-p collisions
at 200 GeV, but applied to Au-Au centrality dependence. The soft-component
reference is a L\'evy distribution on transverse mass $m_t$. The hard-component
reference is a Gaussian on $y_t$ with exponential ($p_t$ power-law) tail.
Deviations of data from the reference are described by hard-component ratio
$r_{AA}$ which generalizes nuclear modification factor $R_{AA}$. The analysis
suggests that centrality evolution of pion and proton spectra is dominated by
changes in parton fragmentation. The structure of $r_{AA}$ suggests that parton
energy loss produces a negative boost $\Delta y_t$ of a large fraction (but not
all) of the minimum-bias fragment distribution, and that lower-energy partons
suffer relatively less energy loss, possibly due to color screening. The
analysis also suggests that the anomalous $p/\pi$ ratio may be due to
differences in the parton energy-loss process experienced by the two hadron
species. This analysis provides no evidence for radial flow.


title:
Microdeflectometry - a novel tool to acquire 3D microtopography with
  nanometer height resolution

abstract:
  We introduce "microdeflectometry", a novel technique for measuring the
microtopography of specular surfaces. The primary data is the local slope of
the surface under test. Measuring the slope instead of the height implies high
information efficiency and extreme sensitivity to local shape irregularities.
The lateral resolution can be better than one micron whereas the resulting
height resolution is in the range of one nanometer. Microdeflectometry can be
supplemented by methods to expand the depth of field, with the potential to
provide quantitative 3D imaging with SEM-like features.


title: Elemental Abundances in PG1159 Stars

abstract:
  The hydrogen-deficiency in extremely hot post-AGB stars of spectral class
PG1159 is probably caused by a (very) late helium-shell flash or a AGB final
thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden
intershell region. Thus, the photospheric elemental abundances of these stars
allow to draw conclusions about details of nuclear burning and mixing processes
in the precursor AGB stars. We compare predicted elemental abundances to those
determined by quantitative spectral analyses performed with advanced non-LTE
model atmospheres. A good qualitative and quantitative agreement is found for
many species (He, C, N, O, Ne, F, Si, Ar) but discrepancies for others (P, S,
Fe) point at shortcomings in stellar evolution models for AGB stars. PG1159
stars appear to be the direct progeny of [WC] stars.


title: Scalar perturbations in Randall-Sundrum braneworld cosmology

abstract:
  We study the evolution of scalar perturbations in the radiation-dominated era
of Randall-Sundrum braneworld cosmology by numerically solving the coupled bulk
and brane master wave equations. We find that density perturbations with
wavelengths less than a critical value (set by the bulk curvature length) are
amplified during horizon re-entry. Conversely, we explicitly confirm from
simulations that the spectrum is identical to GR on large scales. Although this
magnification is not relevant for the cosmic microwave background or
measurements of large scale structure, it may have some bearing on the
formation of primordial black holes in Randall-Sundrum models.


title: A Numerical Algorithm for Zero Counting. I: Complexity and Accuracy

abstract:
  We describe an algorithm to count the number of distinct real zeros of a
polynomial (square) system f. The algorithm performs O(n D kappa(f)) iterations
where n is the number of polynomials (as well as the dimension of the ambient
space), D is a bound on the polynomials' degree, and kappa(f) is a condition
number for the system. Each iteration uses an exponential number of operations.
The algorithm uses finite-precision arithmetic and a polynomial bound for the
precision required to ensure the returned output is correct is exhibited. This
bound is a major feature of our algorithm since it is in contrast with the
exponential precision required by the existing (symbolic) algorithms for
counting real zeros. The algorithm parallelizes well in the sense that each
iteration can be computed in parallel polynomial time with an exponential
number of processors.


title:
A multigroup diffusion solver using pseudo transient continuation for a
  radiation-hydrodynamic code with patch-based AMR

abstract:
  We present a scheme to solve the nonlinear multigroup radiation diffusion
(MGD) equations. The method is incorporated into a massively parallel,
multidimensional, Eulerian radiation-hydrodynamic code with adaptive mesh
refinement (AMR). The patch-based AMR algorithm refines in both space and time
creating a hierarchy of levels, coarsest to finest. The physics modules are
time-advanced using operator splitting. On each level, separate level-solve
packages advance the modules. Our multigroup level-solve adapts an implicit
procedure which leads to a two-step iterative scheme that alternates between
elliptic solves for each group with intra-cell group coupling. For robustness,
we introduce pseudo transient continuation (PTC). We analyze the magnitude of
the PTC parameter to ensure positivity of the resulting linear system, diagonal
dominance and convergence of the two-step scheme. For AMR, a level defines a
subdomain for refinement. For diffusive processes such as MGD, the refined
level uses Dirichet boundary data at the coarse-fine interface and the data is
derived from the coarse level solution. After advancing on the fine level, an
additional procedure, the sync-solve (SS), is required in order to enforce
conservation. The MGD SS reduces to an elliptic solve on a combined grid for a
system of G equations, where G is the number of groups. We adapt the partial
temperature scheme for the SS; hence, we reuse the infrastructure developed for
scalar equations. Results are presented. (Abridged)


title: Global formality at the $G_\infty$-level

abstract:
  In this paper we prove that the sheaf of $\Lscr$-poly-differential operators
for a locally free Lie algebroid $\Lscr$ is formal when viewed as a sheaf of
$G_\infty$-algebras via Tamarkin's morphism of DG-operads $G_\infty\r
B_\infty$.
  In an appendix we prove a strengthening of Halbout's globalization result for
Tamarkin's local quasi-isomorphism.


title:
An optical phase-locking with large and tunable frequency difference
  based on vertical-cavity surface-emitting laser

abstract:
  We present a novel technique to phase-lock two lasers with controllable
frequency difference. In our setup, one sideband of a current modulated
Vertical-Cavity Surface-Emitting Laser (VCSEL) is phase locked to the master
laser by injection seeding, while another sideband of the VCSEL is used to
phase lock the slave laser. The slave laser is therefore locked in phase with
the master laser, with a frequency difference tunable up to about 35 GHz. The
sideband suppression rate of the slave laser is more than 30dB at 30 uW seed
power. The heterodyne spectrum between master and slave has a linewidth of less
than 1 Hz. A coherent population trapping resonance of rubidium is achieved
using such beams.


title:
Giant Radio Galaxies as a probe of the cosmological evolution of the
  IGM, I. Preliminary deep detections and low-resolution spectroscopy with the
  SALT

abstract:
  A problem of the cosmological evolution of the IGM is recalled and a
necessity to find distant (z>0.5) giant radio galaxies (GRGs) with the lobe
energy densities lower than about 10^{-14} J m^{-3} to solve this problem is
emphasized. Therefore we undertake a search for such GRGs on the southern sky
hemisphere using the SALT. In this paper we present a selected sample of the
GRG candidates and the first deep detections of distant host galaxies, as well
as the low-resolution spectra of the galaxies identified on the DSS frames. The
data collected during the Performance Verification (P-V) phase show that 21 of
35 galaxies with the spectroscopic redshift have the projected linear size
greater than 1 Mpc (for H_{0}=71 km\s\Mpc). However their redshifts do not
exceed the value of 0.4 and the energy density in only two of them is less than
10^{-14} J m^{-3}. A photometric redshift estimate of one of them (J1420-0545)
suggests a linear extent larger than 4.8 Mpc, i.e. a larger than that of 3C236,
the largest GRG known up to now.


title: Time-dependent magnetohydrodynamic self-similar extragalactic jets

abstract:
  Extragalactic jets are visualized as dynamic erruptive events modelled by
time-dependent magnetohydrodynamic (MHD) equations. The jet structure comes
through the temporally self-similar solutions in two-dimensional axisymmetric
spherical geometry. The two-dimensional magnetic field is solved in the finite
plasma pressure regime, or finite $\beta$ regime, and it is described by an
equation where plasma pressure plays the role of an eigenvalue. This allows a
structure of magnetic lobes in space, among which the polar axis lobe is
strongly peaked in intensity and collimated in angular spread comparing to the
others. For this reason, the polar lobe overwhelmes the other lobes, and a jet
structure arises in the polar direction naturally. Furthermore, within each
magnetic lobe in space, there are small secondary regions with closed
two-dimensional field lines embedded along this primary lobe. In these embedded
magnetic toroids, plasma pressure and mass density are much higher accordingly.
These are termed as secondary plasmoids. The magnetic field lines in these
secondary plasmoids circle in alternating sequence such that adjacent plasmoids
have opposite field lines. In particular, along the polar primary lobe, such
periodic plasmoid structure happens to be compatible with radio observations
where islands of high radio intensities are mapped.


title: The External Fundamental Group of an Algebraic Number Field

abstract:
  We associate to every algebraic number field a hyperbolic surface lamination
and an external fundamental group: the latter a generalization of the
fundamental germ that necessarily contains external (not first order definable)
elements. The external fundamental group of the rationals is a split extension
of the absolute Galois group, that conjecturally contains a subgroup whose
abelianization is isomorphic to the idele class group.


title: KPD0005+5106: Hottest DO White Dwarf Much Hotter Than Assumed

abstract:
  KPD0005+5106 is the hottest known helium-rich white dwarf. We have identified
NeVIII lines in UV and optical spectra and conclude that it is significantly
hotter than previously thought, namely Teff=200,000 K instead of 120,000 K.
This is a possible explanation for the observed hard X-ray emission as being of
photospheric origin. Concerning its evolutionary state, we suggest that
KPD0005+5106 is not a descendant of a PG1159 star but more probably related to
the O(He) stars and RCrB stars.


title: The predictability of letters in written english

abstract:
  We show that the predictability of letters in written English texts depends
strongly on their position in the word. The first letters are usually the least
easy to predict. This agrees with the intuitive notion that words are well
defined subunits in written languages, with much weaker correlations across
these units than within them. It implies that the average entropy of a letter
deep inside a word is roughly 4 times smaller than the entropy of the first
letter.


title: Gravity Multiplet on KS and BB Backgrounds

abstract:
  In this paper we study the spectra of glueballs on the Klebanov-Strassler
background and its extension to the baryonic branch. We numerically calculate
the mass spectrum of glueballs from the spin 2 ``gravity'' multiplet, which
contains the traceless part of the stress-energy tensor and the transverse part
of the U(1) R-current. The mass spectra of the corresponding fluctuations in
supergravity coincide due to supersymmetry, which is manifest in the effective
five-dimensional theory through a Supersymmetric Quantum Mechanics
transformation. We show that the glueball spectra grow as m^2 ~ Un^2 for large
values of the baryonic branch parameter U.


title: 40 Years of Pulsars: The Birth and Evolution of Isolated Radio Pulsars

abstract:
  We investigate the birth and evolution of isolated radio pulsars using a
population synthesis method, modeling the birth properties of the pulsars,
their time evolution, and their detection in the Parkes and Swinburne Multibeam
(MB) surveys. Together, the Parkes and Swinburne MB surveys have detected
nearly 2/3 of the known pulsars and provide a remarkably homogeneous sample to
compare with simulations. New proper motion measurements and an improved model
of the distribution of free electrons in the interstellar medium, NE2001, also
make revisiting these issues particularly worthwhile. We present a simple
population model that reproduces the actual observations well, and consider
others that fail. We conclude that: pulsars are born in the spiral arms, with
the birthrate of 2.8+/-0.5 pulsars/century peaking at a distance ~3 kpc from
the Galactic centre, and with mean initial speed of 380^{+40}_{-60} km/s; the
birth spin period distribution extends to several hundred milliseconds, with no
evidence of multimodality, implying that characteristic ages overestimate the
true ages of the pulsars by a median factor >2 for true ages <30,000 yr; models
in which the radio luminosities of the pulsars are random generically fail to
reproduce the observed P-Pdot diagram, suggesting a relation between intrinsic
radio luminosity and (P, Pdot); radio luminosities L Edot^0.5 provide a good
match to the observed P-Pdot diagram; for this favored radio luminosity model,
we find no evidence for significant magnetic field decay over the lifetime of
the pulsars as radio sources ~100 Myr.


title: Width of Radio-Loud and Radio-Quiet CMEs

abstract:
  In the present paper we report on the difference in angular sizes between
radio-loud and radio-quiet CMEs. For this purpose we compiled these two samples
of events using Wind/WAVES and SOHO/LASCO observations obtained during
1996-2005. It is shown that the radio-loud CMEs are almost two times wider than
the radio-quiet CMEs (considering expanding parts of CMEs). Furthermore we show
that the radio-quiet CMEs have a narrow expanding bright part with a large
extended diffusive structure. These results were obtained by measuring the CME
widths in three different ways.


title: Faltung formulation of hadron halo event cascade at Mt. Chacaltaya

abstract:
  It is shown that the fundamental standard hadron cascade diffusion equation
in the Mellin transform space is not rigorously correct because of the
inconsistent double energy integral evaluation which generates the function
$<\eta^{s}>$ with its associated parametizations. To ensure an exact basic
working equation, the Faltung integral representation is introduced which has
the elasticity distribution function $u(\eta)$ as the only fundamental input
function and $<\eta^{s}>$ is just the Mellin transform of $u(\eta)$. This
Faltung representation eliminates standard phenomenological parameters which
serve only to mislead the physics of cascade. The exact flux transform equation
is solved by the method of characteristics, and the hadron flux in real space
is obtained by the inverse transform in terms of the simple and essential
residues. Since the essential residues are given by the singularities in the
elasticity distribution and particle production transforms that appear in the
exponentials, these functions should not be parametized arbitrarily to avoid
introducing non-physical essential residues. This Faltung formulation is
applied to the charged hadron integrated energy spectra of halo events detected
at Mt. Chacaltaya by the Brazil-Japan Collaboration, where the incoming flux at
the atmospheric boundary is a single energetic nucleon.


title:
Lusztig isomorphisms for Drinfel'd doubles of bosonizations of Nichols
  algebras of diagonal type

abstract:
  In the structure theory of quantized enveloping algebras, the algebra
isomorphisms determined by Lusztig led to the first general construction of PBW
bases of these algebras. Also, they have important applications to the
representation theory of these and related algebras. In the present paper the
Drinfel'd double for a class of graded Hopf algebras is investigated. Various
quantum algebras, including multiparameter quantizations of semisimple Lie
algebras and of Lie superalgebras, are covered by the given definition. For
these Drinfel'd doubles Lusztig maps are defined. It is shown that these maps
induce isomorphisms between doubles of Nichols algebras of diagonal type.
Further, the obtained isomorphisms satisfy Coxeter type relations in a
generalized sense. As an application, the Lusztig isomorphisms are used to give
a characterization of Nichols algebras of diagonal type with finite arithmetic
root system.
  Key words: Hopf algebra, quantum group, Weyl groupoid


title:
A Century of Cosmology: A Direct Precision Measurement of the
  Intergalactic Lyman-alpha Opacity at 2<z<4.2

abstract:
  We directly measure the evolution of the intergalactic Lyman-alpha effective
optical depth, tau_eff, over the redshift range 2<z<4.2 from a sample of 86
high-resolution, high-signal-to-noise quasar spectra obtained with Keck/ESI,
Keck/HIRES, and Magellan/MIKE. We find that our estimates of the quasar
continuum levels in the Ly-alpha forest obtained by spline fitting are
systematically biased low, but that this bias can be accounted for using mock
spectra. The mean fractional error <Delta C/C_true> is <1% at z=2, 4% at z=3,
and 12% at z=4. We provide estimates of the level of absorption arising from
metals in the Ly-alpha forest based on both direct and statistical metal
removal results in the literature, finding that this contribution is ~6-9% at
z=3 and decreases monotonically with redshift. The high precision of our
measurement indicates significant departures from the best-fit power-law
redshift evolution, particularly near z=3.2.


title: The Solar Argon Abundance

abstract:
  The solar argon abundance cannot be directly derived by spectroscopic
observations of the solar photosphere. The solar Ar abundance is evaluated from
solar wind measurements, nucleosynthetic arguments, observations of B stars,
HII regions, planetary nebulae, and noble gas abundances measured in Jupiter's
atmosphere. These data lead to a recommended argon abundance of N(Ar) =
91,200(+/-)23,700 (on a scale where Si = 10^6 atoms). The recommended abundance
for the solar photosphere (on a scale where log N(H) = 12) is A(Ar)photo =
6.50(+/-)0.10, and taking element settling into account, the solar system
(protosolar) abundance is A(Ar)solsys = 6.57(+/-)0.10.


title:
A new possibility to estimate the width, source location and velocity of
  halo CMEs

abstract:
  It is well know that the coronagraphic observations of halo CMEs are subject
to projection effects. Viewing in the plane of the sky does not allow us to
determine the crucial parameters defining geoeffectivness of CMEs, such as the
velocity, width or source location. We assume that halo CMEs at the beginning
phase of propagation have constant velocities, are symmetric and propagate with
constant angular widths. Using these approximations and determining projected
velocities and difference between times when CME appears on the opposite sides
of the occulting disk we are able to get the necessary parameters. We present
consideration for the whole halo CMEs from SOHO/LASCO catalog until the end of
2000. We show that the halo CMEs are in average much more faster and wider than
the all CMEs from the SOHO/LASCO catalog.


title:
Observations of Dense Molecular Gas in a Quasar Host Galaxy at z=6.42:
  Further Evidence for a Non-Linear Dense Gas - Star Formation Relation at
  Early Cosmic Times

abstract:
  We report a sensitive search for the HCN(J=2-1) emission line towards SDSS
J1148+5251 at z=6.42 with the VLA. HCN emission is a star formation indicator,
tracing dense molecular hydrogen gas (n(H2) >= 10^4 cm^-3) within star-forming
molecular clouds. No emission was detected in the deep interferometer maps of
J1148+5251. We derive a limit for the HCN line luminosity of L'(HCN) < 3.3 x
10^9 K km/s pc^2, corresponding to a HCN/CO luminosity ratio of L'(HCN)/L'(CO)
< 0.13. This limit is consistent with a fraction of dense molecular gas in
J1148+5251 within the range of nearby ultraluminous infrared galaxies (ULIRGs;
median value: L'(HCN)/L'(CO) = 0.17 {+0.05/-0.08}) and HCN-detected z>2
galaxies (0.17 {+0.09/-0.08}). The relationship between L'(HCN) and L(FIR) is
considered to be a measure for the efficiency at which stars form out of dense
gas. In the nearby universe, these quantities show a linear correlation, and
thus, a practically constant average ratio. In J1148+5251, we find
L(FIR)/L'(HCN) > 6600. This is significantly higher than the average ratios for
normal nearby spiral galaxies (L(FIR)/L'(HCN) = 580 {+510/-270}) and ULIRGs
(740 {+505/-50}), but consistent with a rising trend as indicated by other z>2
galaxies (predominantly quasars; 1525 {+1300/-475}). It is unlikely that this
rising trend can be accounted for by a contribution of AGN heating to L(FIR)
alone, and may hint at a higher median gas density and/or elevated
star-formation efficiency toward the more luminous high-redshift systems. There
is marginal evidence that the L(FIR)/L'(HCN) ratio in J1148+5251 may even
exceed the rising trend set by other z>2 galaxies; however, only future
facilities with very large collecting areas such as the SKA will offer the
sensitivity required to further investigate this question.


title: Geoeffectiveness of halo CMEs

abstract:
  Halo coronal mass ejections (HCMEs) originating from regions close to the
center of the Sun are likely to be geoeffective. Assuming that the shape of
HCMEs is a cone and they propagate with constant angular widths and velocities,
at least in their early phase, we have developed a technique (Michalek et al.
2003) which allowed us to obtain the space speed, width and source location. We
apply this technique to obtain the parameters of all full HCMEs observed by the
Solar and Heliospheric Observatory (SOHO) mission's Large Angle and
Spectrometric Coronagraph (LASCO) experiment until the end of 2002. Using this
data we examine which parameters determine the geoeffectiveness of HCMEs. We
show that in the considered period of time only fast halo CMEs (with the space
velocities higher than $\sim 1000{km\over s}$ and originating from the western
hemisphere close to the solar center could cause the severe geomagnetic storms.
We illustrate how the HCME parameters can be used for space weather forecast.
It is also demonstrated that the strength of a geomagnetic storm does not
depend on the determined width of HCMEs. This means that HCMEs do not have to
be very large to cause major geomagnetic storms.


title:
Power law eigenvalue density, scaling and critical random matrix
  ensembles

abstract:
  We consider a class of rotationally invariant unitary random matrix ensembles
where the eigenvalue density falls off as an inverse power law. Under a new
scaling appropriate for such power law densities (different from the scaling
required in Gaussian random matrix ensembles), we calculate exactly the
two-level kernel that determines all eigenvalue correlations. We show that such
ensembles belong to the class of critical ensembles.


title: The Gravitino-Stau Scenario after Catalyzed BBN

abstract:
  We consider the impact of Catalyzed Big Bang Nucleosynthesis on theories with
a gravitino LSP and a charged slepton NLSP. In models where the gravitino to
gaugino mass ratio is bounded from below, such as gaugino-mediated SUSY
breaking, we derive a lower bound on the gaugino mass parameter m_1/2. As a
concrete example, we determine the parameter space of gaugino mediation that is
compatible with all cosmological constraints.


title:
Lepton flavor violation as a probe of squark mixing in supersymmetric
  SU(5)

abstract:
  We study flavor violation in a supersymmetric SU(5) grand unification
scenario in a model-independent way employing mass insertions. We examine how
the quark and the lepton sector observables restrict sfermion mixings. In many
cases, a lepton flavor violating process provides a stringent constraint on the
flavor structure of right-handed down-type squarks. In particular, mu -> e
gamma turns out to be highly susceptible to the 1-3 and 2-3 mixings thereof,
due to the radiative correction from the top Yukawa coupling to the scalar mass
terms of 10. We also discuss projected sensitivity of forthcoming experiments,
and ways to maintain the power of leptonic restrictions even after
incorporating a solution to fix the incorrect quark-lepton mass relations.


title: Exponentially Modified QCD Coupling

abstract:
  We present a specific class of models for an infrared-finite analytic QCD
coupling, such that at large space-like energy scales the coupling differs from
the perturbative one by less than any inverse power of the energy scale. This
condition is motivated by the ITEP Operator Product Expansion philosophy.
Allowed by the ambiguity in the analytization of the perturbative coupling, the
proposed class of couplings has three parameters. In the intermediate energy
region, the proposed coupling has low loop-level and renormalization scheme
dependence. The present modification of perturbative QCD must be considered as
a phenomenological attempt, with the aim of enlarging the applicability range
of the theory of the strong interactions at low energies.


title:
About Compiled Catalogue of Spectroscopically Determined
  $\alpha$-Elements Abundances for Stars with Accurate Parallaxes

abstract:
  We present a new version of the compiled catalogue of nearby stars for which
was published the spectoscopically determined effective temperatures, surface
gravities, and abundances of iron, magnesium, calcium, silicon, and titanium.
Distances, velocity components, galactic orbital elements, and ages was
calculated for all stars. The atmospheric parameters and iron abundances were
found from 4700 values in 136 publications, while relative abundances of
alpha-elements were found from 2800 values in 81 publications for ~2000 dwarfs
and giants using a three-step iteration averaging procedure, with weights
assigned to each source of data as well as to each individual determination and
taking into account systematic deviations of each scale relative to the reduced
mean scale. The estimated assumed completeness for data sources containing more
than five stars, up to late April 2007, exceeds 90%. For the vast majority of
stars in the catalogue, the spatial-velocity components were derived from
modern high-precision astrometric observations, and their Galactic orbit
elements were computed using a three-component model of the Galaxy, consisting
of a disk, a bulge, and a massive extended halo. Ages was determined for dwarfs
and subgiants using Yale isochrones~2004. For this purpose the original codes
was developed, based on interpolation with the 3D-spline functions of
theoretical isochrones, and with subsequent interpolation in metallicity and
abundances of \alpha-elements.


title: On the action principle for a system of differential equations

abstract:
  We consider the problem of constructing an action functional for physical
systems whose classical equations of motion cannot be directly identified with
Euler-Lagrange equations for an action principle. Two ways of action principle
construction are presented. From simple consideration, we derive necessary and
sufficient conditions for the existence of a multiplier matrix which can endow
a prescribed set of second-order differential equations with the structure of
Euler-Lagrange equations. An explicit form of the action is constructed in case
if such a multiplier exists. If a given set of differential equations cannot be
derived from an action principle, one can reformulate such a set in an
equivalent first-order form which can always be treated as the Euler-Lagrange
equations of a certain action. We construct such an action explicitly. There
exists an ambiguity (not reduced to a total time derivative) in associating a
Lagrange function with a given set of equations. We present a complete
description of this ambiguity. The general procedure is illustrated by several
examples.


title: Kinematical Analogy for Marginal Dyon Decay

abstract:
  We describe a kinematical analogy for the marginal decay of 1/4-BPS dyons in
4-dimensional N=4 string compactifications. In this analogy, the electric and
magnetic charges play the role of spatial momenta, the BPS mass plays the role
of energy, and 1/2-BPS dyons correspond to massless particles. Using SO(12,1)
"Lorentz" invariance and standard kinematical formulae in particle physics, we
provide simple derivations of the curves of marginal stability. We also show
how these curves map into the momentum ellipsoid, and propose some applications
of this analogy.


title:
Stellar dynamics of blue compact galaxies. II. Further indications of a
  merger in ESO 338-IG04

abstract:
  Luminous blue compact galaxies, common at z~1 but now relatively rare, show
disturbed kinematics in emission lines. As part of a programme to understand
their formation and evolution, we have investigated the stellar dynamics of a
number of nearby objects in this class. We obtained long-slit spectra with
VLT/FORS2 in the spectral region covering the near-infrared calcium triplet. In
this paper we focus on the well-known luminous blue compact galaxy ESO 338-IG04
(Tololo 1924-416). A previous investigation, using Fabry-Perot interferometry,
showed that this galaxy has a chaotic H-alpha velocity field, indicating that
either the galaxy is not in dynamical equilibrium or that H-alpha does not
trace the gravitational potential due to feedback from star formation. Along
the apparent major axis, the stellar and ionised gas velocities for the most
part follow each other. The chaotic velocity field must therefore be a sign
that the young stellar population in ESO 338-IG04 is not in dynamical
equilibrium. The most likely explanation, which is also supported by its
morphology, is that the galaxy has experienced a merger and that this has
triggered the current starburst. Summarising the results of our programme so
far, we note that emission-line velocity fields are not always reliable tracers
of stellar motions, and go on to assess the implications for kinematic studies
of similar galaxies at intermediate redshift.


title: Akivis Superalgebras and speciality

abstract:
  In this paper we define Akivis superalgebra and study enveloping
superalgebras for this class of algebras, proving an analogous of the PBW
Theorem. Lie and Malcev superalgebras are examples of Akivis superalgebras. For
these particular superalgebras, we describe the connection between the
classical enveloping superalgebras and the corresponding generalized concept
defined in this work.


title:
Bayesian treed Gaussian process models with an application to computer
  modeling

abstract:
  Motivated by a computer experiment for the design of a rocket booster, this
paper explores nonstationary modeling methodologies that couple stationary
Gaussian processes with treed partitioning. Partitioning is a simple but
effective method for dealing with nonstationarity. The methodological
developments and statistical computing details which make this approach
efficient are described in detail. In addition to providing an analysis of the
rocket booster simulator, our approach is demonstrated to be effective in other
arenas.


title: An Asymmetric Cone Model for Halo Coronal Mass Ejections

abstract:
  Due to projection effects, coronagraphic observations cannot uniquely
determine parameters relevant to the geoeffectiveness of CMEs, such as the true
propagation speed, width, or source location. The Cone Model for Coronal Mass
Ejections (CMEs) has been studied in this respect and it could be used to
obtain these parameters. There are evidences that some CMEs initiate from a
flux-rope topology. It seems that these CMEs should be elongated along the
flux-rope axis and the cross section of the cone base should be rather
elliptical than circular. In the present paper we applied an asymmetric cone
model to get the real space parameters of frontsided halo CMEs (HCMEs) recorded
by SOHO/LASCO coronagraphs in 2002. The cone model parameters are generated
through a fitting procedure to the projected speeds measured at different
position angles on the plane of the sky. We consider models with the apex of
the cone located at the center and surface of the Sun. The results are compared
to the standard symmetric cone model.


title: The Pion Form Factor at Large Momentum Transfer

abstract:
  We present our calculations of the electromagnetic form factor of pions. We
explore the properties of pion form factor at momentum transfer larger than
previous studies by including more combinations of source and sink momenta and
using more configurations.We fit our results using vector meson dominance (VMD)
hypothesis.


title:
Boundary structure and size in terms of interior and exterior harmonic
  measures in higher dimensions

abstract:
  In this work we introduce the use of powerful tools from geometric measure
theory (GMT) to study problems related to the size and structure of sets of
mutual absolute continuity for the inside and outside harmonic measures of
domains in n-dimensional Euclidean space, with n bigger than or equal to 3.


title: Bulk-brane supergravity

abstract:
  We point out a limitation of the existing supergravity tensor calculus on the
$S^1/Z_2$ orbifold that prevents its use for constructing general
supersymmetric bulk-plus-brane actions. We report on the progress achieved in
removing this limitation via the development of ``supersymmetry without
boundary conditions.''


title:
Towards a microscopic construction of flavour vacua from a space-time
  foam model

abstract:
  The effect on flavour oscillations of simple expanding background
space-times, motivated by some D-particle foam models, is calculated for a
toy-model of bosons with flavour degrees of freedom. The presence of D-particle
defects in the space-time, which can interact non trivially (via particle
capture) with flavoured particles in a flavour non-preserving way, generates
mixing in the effective field theory of low-energy string excitations.
Moreover, the recoil of the D-particle defect during the capture/scattering
process implies Lorentz violation, which however may be averaged to zero in
isotropic D-particle populations, but implies non-trivial effects in
correlators. Both features imply that the flavoured mixed state sees a
non-trivial flavour (Fock-space) vacuum of a type introduced earlier by Blasone
and Vitiello in a generic context of theories with mixing. We discuss the
orthogonality of the flavour vacua to the usual Fock vacua and the effect on
flavour oscillations in these backgrounds. Furthermore we analyse the equation
of state of the Flavour vacuum, and find that, for slow expansion rates induced
by D particle recoil, it is equivalent to that of a cosmological constant. Some
estimates of these novel non-perturbative contribution to the vacuum energy are
made. The contribution vanishes if the mass difference and the mixing angle of
the flavoured states vanish.


title:
Determination of spin polarization in InAs/GaAs self-assembled quantum
  dots

abstract:
  The spin polarization of electrons trapped in InAs self-assembled quantum dot
ensembles is investigated. A statistical approach for the population of the
spin levels allows one to infer the spin polarization from the measure values
of the addition energies. From the magneto-capacitance spectroscopy data, the
authors found a fully polarized ensemble of electronic spins above 10 T when
$\mathbf{B}\parallel[001]$ and at 2.8 K. Finally, by including the g-tensor
anisotropy the angular dependence of spin polarization with the magnetic field
$\mathbf{B}$ orientation and strength could be determined.


title: Quantum bounce and cosmic recall

abstract:
  Loop quantum cosmology predicts that, in simple models, the big bang
singularity of classical general relativity is replaced by a quantum bounce.
Because of the extreme physical conditions near the bounce, a natural question
is whether the universe can retain, after the bounce, its memory about the
previous epoch. More precisely, does the universe retain various properties of
the state after evolving unitarily through the bounce or does it suffer from
some cosmic amnesia as has been recently suggested? Here we show that this
issue can be answered unambiguously at least within an exactly solvable model,
derived from a small simplification of loop quantum cosmology, for which there
is full analytical control on the quantum theory. We show that if there exists
a semiclassical state at late times on one side, peaked around a pair of
canonically conjugate variables, then there are very strong bounds on the
fluctuations on the other side of the bounce, implying semi-classicality. For
such a model universe which grows to a size of 1 megaparsec, at late times, the
change in relative fluctuations of the only non-trivial observable of the model
across the bounce is less than $10^{-56}$ (becoming smaller for universes which
grow larger). The universe maintains (an almost) total recall.


title: Quadratic Malcev Superalgebras with reductive even part

abstract:
  It is our goal to give an inductive description of quadratic Malcev
superalgebras with reductive even part. We use the notion of double extension
of Malcev superalgebras presented by H. Albuquerque and S. Benayadi and
transfer to Malcev superalgebras the concept of generalized double extension
for Lie superalgebras.


title:
The Fine-Structure of the Net-Circular Polarization in a Sunspot
  Penumbra

abstract:
  We present novel evidence for a fine structure observed in the net-circular
polarization (NCP) of a sunspot penumbra based on spectropolarimetric
measurements utilizing the Zeeman sensitive FeI 630.2 nm line. For the first
time we detect a filamentary organized fine structure of the NCP on spatial
scales that are similar to the inhomogeneities found in the penumbral flow
field. We also observe an additional property of the visible NCP, a
zero-crossing of the NCP in the outer parts of the center-side penumbra, which
has not been recognized before. In order to interprete the observations we
solve the radiative transfer equations for polarized light in a model penumbra
with embedded magnetic flux tubes. We demonstrate that the observed
zero-crossing of the NCP can be explained by an increased magnetic field
strength inside magnetic flux tubes in the outer penumbra combined with a
decreased magnetic field strength in the background field. Our results strongly
support the concept of the uncombed penumbra.


title: SUSY Parameters Determination with ATLAS

abstract:
  The plan for mass and spin measurement of SUSY particles with the ATLAS
detector is presented. The measurements of kinematical distributions, such as
edges in the invariant mass of leptons and jets, could be used to constrain the
model of SUSY that may be discovered at the LHC. Examples from a few points in
the mSUGRA scenario are provided with an emphasis on measurements that can be
conducted within the first few years of data taking.


title: The population of propellers in Saturn's A Ring

abstract:
  We present an extensive data set of ~150 localized features from Cassini
images of Saturn's Ring A, a third of which are demonstrated to be persistent
by their appearance in multiple images, and half of which are resolved well
enough to reveal a characteristic "propeller" shape. We interpret these
features as the signatures of small moonlets embedded within the ring, with
diameters between 40 and 500 meters. The lack of significant brightening at
high phase angle indicates that they are likely composed primarily of
macroscopic particles, rather than dust. With the exception of two features
found exterior to the Encke Gap, these objects are concentrated entirely within
three narrow (~1000 km) bands in the mid-A Ring that happen to be free from
local disturbances from strong density waves. However, other nearby regions are
similarly free of major disturbances but contain no propellers. It is unclear
whether these bands are due to specific events in which a parent body or bodies
broke up into the current moonlets, or whether a larger initial moonlet
population has been sculpted into bands by other ring processes.


title: CBBN in the CMSSM

abstract:
  Catalyzed big bang nucleosynthesis (CBBN) can lead to an overproduction of
^6Li in gravitino dark matter scenarios in which the lighter stau is the
lightest Standard Model superpartner. Based on a treatment using the
state-of-the-art result for the catalyzed ^6Li production cross section, we
update the resulting constraint within the framework of the constrained minimal
supersymmetric Standard Model (CMSSM). We confront our numerical findings with
recently derived conservative limits on the gaugino mass parameter and the
reheating temperature.


title:
Chemical composition and mixing in giant HII regions: NGC3603,
  30Doradus, and N66

abstract:
  We investigate the chemical abundances of NGC3603 in the Milky Way, of
30Doradus in the Large Magellanic Cloud, and of N66 in the Small Magellanic
Cloud. Mid-infrared observations with the Infrared Spectrograph onboard the
Spitzer Space Telescope allow us to probe the properties of distinct physical
regions within each object: the central ionizing cluster, the surrounding
ionized gas, photodissociation regions, and buried stellar clusters. We detect
[SIII], [SIV], [ArIII], [NeII], [NeIII], [FeII], and [FeIII] lines and derive
the ionic abundances. Based on the ionic abundance ratio (NeIII/H)/(SIII/H), we
find that the gas observed in the MIR is characterized by a higher degree of
ionization than the gas observed in the optical spectra. We compute the
elemental abundances of Ne, S, Ar, and Fe. We find that the alpha-elements Ne,
S, and Ar scale with each other. Our determinations agree well with the
abundances derived from the optical. The Ne/S ratio is higher than the solar
value in the three giant HII regions and points toward a moderate depletion of
sulfur on dust grains. We find that the neon and sulfur abundances display a
remarkably small dispersion (0.11dex in 15 positions in 30Doradus), suggesting
a relatively homogeneous ISM, even though small-scale mixing cannot be ruled
out.


title:
Ginzburg-Landau theory for the conical cycloid state in multiferroics:
  applications to CoCr$_2$O$_4$

abstract:
  We show that the cycloidal magnetic order of a multiferroic can arise in the
absence of spin and lattice anisotropies, for e.g., in a cubic material, and
this explains the occurrence of such a state in CoCr$_2$O$_4$. We discuss the
case when this order coexists with ferromagnetism in a so called `conical
cycloid' state, and show that a direct transition to this state from the
ferromagnet is necessarily first order. On quite general grounds, the reversal
of the direction of the uniform magnetization in this state can lead to the
reversal of the electric polarization as well, without the need to invoke
`toroidal moment' as the order parameter.


title:
Goldstone modes and electromagnon fluctuations in the conical cycloid
  state of a multiferroic

abstract:
  Using a phenomenological Ginzburg-Landau theory for the magnetic conical
cycloid state of a multiferroic, which has been recently reported in the cubic
spinel CoCr$_{2}$O$_{4}$, we discuss its low-energy fluctuation spectrum. We
identify the Goldstone modes of the conical cycloidal order, and deduce their
dispersion relations whose signature anisotropy in momentum space reflects the
symmetries broken by the ordered state. We discuss the soft polarization
fluctuations, the `electromagnons', associated with these magnetic modes and
make several experimental predictions which can be tested in neutron scattering
and optical experiments.


title:
Evolution of the Bar Fraction in COSMOS: Quantifying the Assembly of the
  Hubble Sequence

abstract:
  We have analyzed the redshift-dependent fraction of galactic bars over
0.2<z<0.84 in 2,157 luminous face-on spiral galaxies from the COSMOS 2-square
degree field. Our sample is an order of magnitude larger than that used in any
previous investigation, and is based on substantially deeper imaging data than
that available from earlier wide-area studies of high-redshift galaxy
morphology. We find that the fraction of barred spirals declines rapidly with
redshift. Whereas in the local Universe about 65% of luminous spiral galaxies
contain bars (SB+SAB), at z ~0.84 this fraction drops to about 20%. Over this
redshift range the fraction of strong (SB) bars drops from about 30% to under
10%. It is clear that when the Universe was half its present age, the census of
galaxies on the Hubble sequence was fundamentally different from that of the
present day. A major clue to understanding this phenomenon has also emerged
from our analysis, which shows that the bar fraction in spiral galaxies is a
strong function of stellar mass, integrated color and bulge prominence. The bar
fraction in very massive, luminous spirals is about constant out to z ~ 0.84
whereas for the low mass, blue spirals it declines significantly with redshift
beyond z=0.3. There is also a slight preference for bars in bulge dominated
systems at high redshifts which may be an important clue towards the
co-evolution of bars, bulges and black holes. Our results thus have important
ramifications for the processes responsible for galactic downsizing, suggesting
that massive galaxies matured early in a dynamical sense, and not just as a
result of the regulation of their star formation rate.