title: Bulk and surface switching in Mn-Fe-based Prussian Blue Analogues

abstract:
  Many Prussian Blue Analogues are known to show a thermally induced phase
transition close to room temperature and a reversible, photo-induced phase
transition at low temperatures. This work reports on magnetic measurements,
X-ray photoemission and Raman spectroscopy on a particular class of these
molecular heterobimetallic systems, specifically on
Rb0.81Mn[Fe(CN)6]0.95_1.24H2O, Rb0.97Mn[Fe(CN)6]0.98_1.03H2O and
Rb0.70Cu0.22Mn0.78[Fe(CN)6]0.86_2.05H2O, to investigate these transition
phenomena both in the bulk of the material and at the sample surface. Results
indicate a high degree of charge transfer in the bulk, while a substantially
reduced conversion is found at the sample surface, even in case of a near
perfect (Rb:Mn:Fe=1:1:1) stoichiometry. Thus, the intrinsic incompleteness of
the charge transfer transition in these materials is found to be primarily due
to surface reconstruction. Substitution of a large fraction of charge transfer
active Mn ions by charge transfer inactive Cu ions leads to a proportional
conversion reduction with respect to the maximum conversion that is still
stoichiometrically possible and shows the charge transfer capability of metal
centers to be quite robust upon inclusion of a neighboring impurity.
Additionally, a 532 nm photo-induced metastable state, reminiscent of the high
temperature Fe(III)Mn(II) ground state, is found at temperatures 50-100 K. The
efficiency of photo-excitation to the metastable state is found to be maximized
around 90 K. The photo-induced state is observed to relax to the low
temperature Fe(II)Mn(III) ground state at a temperature of approximately 123 K.


title: Results and perspectives of the solar neutrino experiment Borexino

abstract:
  Borexino is a massive, calorimetric, liquid scintillator detector aimed at
the detection of low energy sub-MeV solar neutrinos, installed at the Gran
Sasso Laboratory. After several years of construction, data taking started in
May 2007, providing immediately incontrovertible evidence of the unprecedented
radiopurity of the target mass, at the level required to ensure the successful
detection of 7Be solar neutrinos, which was then announced in the 2007 summer.
In this talk first the main technical characteristics of the detector will be
highlighted, with special emphasis on the exceptional purity challenges
successfully faced by the Collaboration, and afterwards the physics outputs
reached so far will be carefully reported and illustrated, together with the
perspectives for the future measurements that will complete the broad program
of the experiment.


title: Coordinated mm/sub-mm observations of Sagittarius A* in May 2007

abstract:
  At the center of the Milky Way, with a distance of ~8 kpc, the compact source
Sagittarius A* (SgrA*) can be associated with a super massive black hole of
~4x10^6 solar masses. SgrA* shows strong variability from the radio to the
X-ray wavelength domains. Here we report on simultaneous
NIR/sub-millimeter/X-ray observations from May 2007 that involved the NACO
adaptive optics (AO) instrument at the European Southern Observatory's Very
Large Telescope, the Australian Telescope Compact Array (ATCA), the US mm-array
CARMA, the IRAM 30m mm-telescope, and other telescopes. We concentrate on the
time series of mm/sub-mm data from CARMA, ATCA, and the MAMBO bolometer at the
IRAM 30m telescope.


title:
Few-electron artificial molecules formed by laterally coupled quantum
  rings

abstract:
  We study the artificial molecular states formed in laterally coupled double
semiconductor nanorings by systems containing one, two and three electrons. An
interplay of the interring tunneling and the electron-electron interaction is
described and its consequences for the magnetization and charging properties of
the system are determined. It is shown that both the magnetic dipole moment
generated by the double ring structure and the chemical potential of the system
as function of the external magnetic field strongly depend on the number of
electrons and the interring barrier thickness. Both the magnetization and
chemical potentials exhibit cusps at the magnetic fields inducing ground-state
parity and / or spin transformations. The symmetry transformations are
discussed for various tunnel coupling strengths: from rings coupled only
electrostatically to the limit of coalesced rings. We find that in the
ground-states for rings of different radii the magnetic field transfers the
electron charge from one ring to the other. The calculations are performed with
the configuration interaction method based on an approach of Gaussian functions
centered on a rectangular array of points covering the studied structure.
Electron-electron correlation is also discussed.


title:
Engineering an all-optical route to ultracold molecules in their
  vibronic ground state

abstract:
  We propose an improved photoassociation scheme to produce ultracold molecules
in their vibronic ground state for the generic case where non-adiabatic effects
facilitating transfer to deeply bound levels are absent. Formation of molecules
is achieved by short laser pulses in a Raman-like pump-dump process where an
additional near-infrared laser field couples the excited state to an auxiliary
state. The coupling due to the additional field effectively changes the shape
of the excited state potential and allows for efficient population transfer to
low-lying vibrational levels of the electronic ground state. Repetition of many
pump-dump sequences together with collisional relaxation allows for
accumulation of molecules in v=0.


title: Effect of Peculiar Motion in Weak Lensing

abstract:
  We study the effect of peculiar motion in weak gravitational lensing. We
derive a fully relativistic formula for the cosmic shear and the convergence in
a perturbed Friedmann Universe. We find a new contribution related to galaxies
peculiar velocity. This contribution does not affect cosmic shear in a
measurable way, since it is of second order in the velocity. However, its
effect on the convergence (and consequently on the magnification, which is a
measurable quantity) is important, especially for redshifts z < 1. As a
consequence, peculiar motion modifies also the relation between the shear and
the convergence.


title: Missing ET Performance in ATLAS

abstract:
  The observation and measurement of missing transverse energy in an event is a
key signature in SUSY searches. This paper describes the reconstruction and
calibration of missing transverse energy in ATLAS, and addresses the quality of
the measurement in a variety of simulated processes which contain physical
missing transverse energy such as $Z$ $\to$ $\tau^{+}\tau^{-}$, $A^{0}$ /
$H^{0}$ $\to$ $\tau^{+}\tau^{-}$, $t$$\bar{t}$, and SUSY as well as processes
which contain no missing transverse energy such as minimum bias and $Z$+jets.
Expectations for the use of early data in evaluation of the measurement of
missing transverse energy are presented.


title:
The s process in massive stars at low metallicity. Effect of primary N14
  from fast rotating stars

abstract:
  The goal of this paper is to analyze the impact of a primary neutron source
on the s-process nucleosynthesis in massive stars at halo metallicity. Recent
stellar models including rotation at very low metallicity predict a strong
production of primary N14. Part of the nitrogen produced in the H-burning shell
diffuses by rotational mixing into the He core where it is converted to Ne22
providing additional neutrons for the s process. We present nucleosynthesis
calculations for a 25 Msun star at [Fe/H] = -3, -4, where in the convective
core He-burning about 0.8 % in mass is made of primary Ne22. The usual weak
s-process shape is changed by the additional neutron source with a peak between
Sr and Ba, where the s-process yields increase by orders of magnitude with
respect to the yields obtained without rotation. Iron seeds are fully consumed
and the maximum production of Sr, Y and Zr is reached. On the other hand, the
s-process efficiency beyond Sr and the ratio Sr/Ba are strongly affected by the
amount of Ne22 and by nuclear uncertainties, first of all by the
Ne22(alpha,n)Mg25 reaction. Finally, assuming that Ne22 is primary in the
considered metallicity range, the s-process efficiency decreases with
metallicity due to the effect of the major neutron poisons Mg25 and Ne22. This
work represents a first step towards the study of primary neutron source effect
in fast rotating massive stars, and its implications are discussed in the light
of spectroscopic observations of heavy elements at halo metallicity.


title: Simultaneous Stabilization in $A_\mathbb{R}(\mathbb{D})$

abstract:
  In this note we study the problem of simultaneous stabilization for the
algebra $A_\R(\D)$. Invertible pairs $(f_j,g_j)$, $j=1,..., n$, in a
commutative unital algebra are called \textit{simultaneously stabilizable} if
there exists a pair $(\alpha,\beta)$ of elements such that $\alpha f_j+\beta
g_j$ is invertible in this algebra for $j=1,..., n$.
  For $n=2$, the simultaneous stabilization problem admits a positive solution
for any data if and only if the Bass stable rank of the algebra is one. Since
$A_\R(\D)$ has stable rank two, we are faced here with a different situation.
When $n=2$, necessary and sufficient conditions are given so that we have
simultaneous stability in $A_\R(\D)$.
  For $n\geq 3$ we show that under these conditions simultaneous stabilization
is not possible and further connect this result to the question of which pairs
$(f,g)$ in $A_\R(\D)^2$ are totally reducible; that is, for which pairs do
there exist two units $u$ and $v$ in $A_\R(\D)$ such that $uf+vg=1$.


title: Hochschild Cohomology and Deformations of Clifford-Weyl Algebras

abstract:
  We give a complete study of the Clifford-Weyl algebra ${\mathcal C}(n,2k)$
from Bose-Fermi statistics, including Hochschild cohomology (with coefficients
in itself). We show that ${\mathcal C}(n,2k)$ is rigid when $n$ is even or when
$k \neq 1$. We find all non-trivial deformations of ${\mathcal C}(2n+1,2)$ and
study their representations.


title:
Periodic perturbations with delay of autonomous differential equations
  on manifolds

abstract:
  We apply topological methods to the study of the set of harmonic solutions of
periodically perturbed autonomous ordinary differential equations on
differentiable manifolds, allowing the perturbing term to contain a fixed
delay.
  In the crucial step, in order to cope with the delay, we define a suitable
(infinite dimensional) notion of Poincar\'e $T$-translation operator and prove
a formula that, in the unperturbed case, allows the computation of its fixed
point index.


title:
Finite groups of units and their composition factors in the integral
  group rings of the groups $\text{PSL}(2,q)$

abstract:
  Let $G$ denote the projective special linear group $\text{PSL}(2,q)$, for a
prime power $q$. It is shown that a finite 2-subgroup of the group
$V(\mathbb{Z}G)$ of augmentation 1 units in the integral group ring
$\mathbb{Z}G$ of $G$ is isomorphic to a subgroup of $G$. Furthermore, it is
shown that a composition factor of a finite subgroup of $V(\mathbb{Z}G)$ is
isomorphic to a subgroup of $G$.


title: Incompressibility and normal minimal surfaces

abstract:
  In this paper we describe a procedure for refining the given triangulation of
a 3-manifold that scales the PL-metric according to a given weight function
while creating no new normal surfaces.
  It is known that an incompressible surface $F$ in a triangulated 3-manifold
$M$ is isotopic to a normal surface that is of minimal PL-area in the isotopy
class of $F$. Using the above scaling refinement we prove the converse. If $F$
is a surface in a closed 3-manifold $M$ such that for any triangulation $\tau$
of $M$, $F$ is isotopic to a $\tau$-normal surface $F(\tau)$ that is of minimal
PL-area in its isotopy class, then we show that $F$ is incompressible.


title: Spinning particles and higher spin fields on (A)dS backgrounds

abstract:
  Spinning particle models can be used to describe higher spin fields in first
quantization. In this paper we discuss how spinning particles with gauged O(N)
supersymmetries on the worldline can be consistently coupled to conformally
flat spacetimes, both at the classical and at the quantum level. In particular,
we consider canonical quantization on flat and on (A)dS backgrounds, and
discuss in detail how the constraints due to the worldline gauge symmetries
produce geometrical equations for higher spin fields, i.e. equations written in
terms of generalized curvatures. On flat space the algebra of constraints is
linear, and one can integrate part of the constraints by introducing gauge
potentials. This way the equivalence of the geometrical formulation with the
standard formulation in terms of gauge potentials is made manifest. On (A)dS
backgrounds the algebra of constraints becomes quadratic, nevertheless one can
use it to extend much of the previous analysis to this case. In particular, we
derive general formulas for expressing the curvatures in terms of gauge
potentials and discuss explicitly the cases of spin 2, 3 and 4.


title:
Non-Gaussianity and Baryonic Isocurvature Fluctuations in the Curvaton
  Scenario

abstract:
  We discuss non-Gaussianity and baryonic isocurvature fluctuations in the
curvaton scenario, assuming that the baryon asymmetry of the universe
originates only from the decay products of the inflaton. When large
non-Gaussianity is realized in such a scenario, non-vanishing baryonic
isocurvature fluctuations can also be generated unless the baryogenesis occurs
after the decay of the curvaton. We calculate the non-linearity parameter f_NL
and the baryonic isocurvature fluctuations, taking account of the primordial
fluctuations of both the inflaton and the curvaton. We show that, although
current constraints on isocurvature fluctuations are severe, the non-linearity
parameter can be large as f_NL \sim O(10-100) without conflicting with the
constraints.


title:
Dynamical Dark Energy simulations: high accuracy Power Spectra at high
  redshift

abstract:
  Accurate predictions on non--linear power spectra, at various redshift z,
will be a basic tool to interpret cosmological data from next generation mass
probes, so obtaining key information on Dark Energy nature. This calls for high
precision simulations, covering the whole functional space of w(z) state
equations and taking also into account the admitted ranges of other
cosmological parameters; surely a difficult task. A procedure was however
suggested, able to match the spectra at z=0, up to k~3, hMpc^{-1}, in
cosmologies with an (almost) arbitrary w(z), by making recourse to the results
of N-body simulations with w = const. In this paper we extend such procedure to
high redshift and test our approach through a series of N-body gravitational
simulations of various models, including a model closely fitting WMAP5 and
complementary data. Our approach detects w= const. models, whose spectra meet
the requirement within 1% at z=0 and perform even better at higher redshift,
where they are close to a permil precision. Available Halofit expressions,
extended to (constant) w \neq -1 are unfortunately unsuitable to fit the
spectra of the physical models considered here. Their extension to cover the
desired range should be however feasible, and this will enable us to match
spectra from any DE state equation.


title:
Global attractors for doubly nonlinear evolution equations with
  non-monotone perturbations

abstract:
  This paper proposes an abstract theory concerned with dynamical systems
generated by doubly nonlinear evolution equations governed by subdifferential
operators with non-monotone perturbations in a reflexive Banach space setting.
In order to construct global attractors, an approach based on the notion of
generalized semiflow is employed instead of the usual semi-group approach,
since solutions of the Cauchy problem for the equation might not be unique.
Moreover, the preceding abstract theory is applied to a generalized Allen-Cahn
equation whose potential is divided into a convex part and a non-convex part as
well as a semilinear parabolic equation with a nonlinear term involving
gradients.


title:
X-ray emission from dense plasma in CTTSs: Hydrodynamic modeling of the
  accretion shock

abstract:
  High spectral resolution X-ray observations of CTTSs demonstrate the presence
of plasma at T~2-3X10^6 K and n_e~10^11-10^13 cm^-3, unobserved in
non-accreting stars. Stationary models suggest that this emission is due to
shock-heated accreting material, but they do not allow to analyze the stability
of such material and its position in the stellar atmosphere. We investigate the
dynamics and the stability of shock-heated accreting material in CTTSs and the
role of the stellar chromosphere in determining the position and the thickness
of the shocked region. We perform 1-D HD simulations of the impact of the
accretion flow onto chromosphere of a CTTS, including the effects of gravity,
radiative losses from optically thin plasma, thermal conduction and a well
tested detailed model of the stellar chromosphere. Here we present the results
of a simulation based on the parameters of the CTTS MP Mus. We find that the
accretion shock generates an hot slab of material above the chromosphere with a
maximum thickness of 1.8X10^9 cm, density n_e~10^11-10^2 cm^-3, temperature
T~3X10^6 K and uniform pressure equal to the ram pressure of the accretion flow
(~450 dyn cm^-2). The base of the shocked region penetrates the chromosphere
and stays where the ram pressure is equal to the thermal pressure. The system
evolves with quasi-periodic instabilities of the material in the slab leading
to cyclic disappearance and re-formation of the slab. For an accretion rate of
~10^-10 M_sun yr^-1, the shocked region emits a time-averaged X-ray luminosity
L_X~7X10^29 erg s^-1, which is comparable to the X-ray luminosity observed in
CTTSs of the same mass. Furthermore, the X-ray spectrum synthesized from the
simulation matches in detail all the main features of the O VIII and O VII
lines of the star MP Mus.


title: Fluctuations relations for semiclassical single-mode laser

abstract:
  Over last decades, the study of laser fluctuations has shown that laser
theory may be regarded as a prototypical example of a nonlinear nonequilibrium
problem. The present paper discusses the fluctuation relations, recently
derived in nonequilibrium statistical mechanics, in the context of the
semiclassical laser theory.


title: The Little Randall-Sundrum Model at the LHC

abstract:
  We present a predictive warped model of flavor, cut off at an ultraviolet
scale O(10^3) TeV, called the "Little Randall-Sundrum (LRS)" model. This model
corresponds to a volume-truncation, by a factor y \approx 6, of the RS scenario
and is holographically dual to dynamics with number of colors larger by y. With
separate gauge and flavor dynamics, several unwanted contributions to precision
electroweak, Z b \bar b, and flavor observables are suppressed in the LRS
framework, compared with the corresponding RS case. The LRS truncation leads to
a significant enhancement of the clean (golden) di-lepton LHC signals, by
O(y^3).


title:
Skew Invariant Theory of Symplectic Groups, Pluri-Hodge Groups and
  3-Manifold Invariants

abstract:
  This article deals with a number of topics which are, somewhat surprisingly,
related. Firstly, the fundamental theorem of skew invariant theory for the
symplectic group giving the generators and relations of symplectic invariants
is established. The relations are the so called P_n relations which appear in
the study of certain 3-manifold invariants. Next a class of cohomology groups
are introduced, called Pluri-Hodge groups (somewhat in keeping with the notion
of pluri-canonical groups). These are Dolbeault groups on a complex manifold X
with values in tensor powers of sheaves of holomorphic forms of various
degrees. By Riemann-Roch one shows that knowledge of the Pluri-Hodge groups
gives precise formulae for all Chern numbers of the manifold. When X is
holomorphic symplectic the Pluri-Hodge groups form representations of Sp(g)
where g counts the number of tensor products. Still with X holomorphic
symplectic, the Pluri-Hodge groups are vectors in the vector space H_g(X) of
states in the topological field theory of Rozansky and Witten for a 3-manifold
with boundary a Riemann surface of genus g. A formulation of the
Murakami-Ohtsuki invariants, due to Sawon, allows us to show that quotients of
the spaces of trivalent graphs B_g carry representations of the symplectic
group. There is a weight system W_X: B_g -> H_g(X) and we show that W_X
preserves the various symplectic group actions.


title: On Brane Solutions Related to Non-Singular Kac-Moody Algebras

abstract:
  A multidimensional gravitational model containing scalar fields and
antisymmetric forms is considered. The manifold is chosen in the form $M = M_0
\times M_1 \times \cdots \times M_n$, where $M_i$ are Einstein spaces ($i \geq
1$). The sigma-model approach and exact solutions with intersecting composite
branes (e.g. solutions with harmonic functions, $S$-brane and black brane ones)
with intersection rules related to non-singular Kac-Moody (KM) algebras (e.g.
hyperbolic ones) are reviewed. Some examples of solutions, e.g. corresponding
to hyperbolic KM algebras: $H_2(q,q)$, $AE_3$, $HA_2^{(1)}$, $E_{10}$ and
Lorentzian KM algebra $P_{10}$ are presented.


title: Nuclear effective field theory on the lattice

abstract:
  In the low-energy region far below the chiral symmetry breaking scale (which
is of the order of 1 GeV) chiral perturbation theory provides a
model-independent approach for quantitative description of nuclear processes.
In the two- and more-nucleon sector perturbation theory is applicable only at
the level of an effective potential which serves as input in the corresponding
dynamical equation. To deal with the resulting many-body problem we put chiral
effective field theory (EFT) on the lattice. Here we present the results of our
lattice EFT study up to next-to-next-to-leading order in the chiral expansion.
Accurate description of two-nucleon phase-shifts and ground state energy ratio
of dilute neutron matter up to corrections of higher orders shows that lattice
EFT is a promising tool for a quantitative description of low-energy few- and
many-body systems.


title: Continuous-Discrete Path Integral Filtering

abstract:
  A summary of the relationship between the Langevin equation,
Fokker-Planck-Kolmogorov forward equation (FPKfe) and the Feynman path integral
descriptions of stochastic processes relevant for the solution of the
continuous-discrete filtering problem is provided in this paper. The practical
utility of the path integral formula is demonstrated via some nontrivial
examples. Specifically, it is shown that the simplest approximation of the path
integral formula for the fundamental solution of the FPKfe can be applied to
solve nonlinear continuous-discrete filtering problems quite accurately. The
Dirac-Feynman path integral filtering algorithm is quite simple, and is
suitable for real-time implementation.


title: Gravitomagnetic effects in Kerr-de Sitter space-time

abstract:
  We explicitly worked out the orbital effects induced on the trajectory of a
test particle by the the weak-field approximation of the Kerr-de Sitter metric.
It results that the node, the pericentre and the mean anomaly undergo secular
precessions proportional to k, which is a measure of the non linearity of the
theory. We used such theoretical predictions and the latest observational
determinations of the non-standard precessions of the perihelia of the inner
planets of the Solar System to put a bound on k getting k <= 10^-29 m^-2. The
node rate of the LAGEOS Earth's satellite yields k <= 10^-26 m^-2. The
periastron precession of the double pulsar PSR J0737-3039A/B allows to obtain k
<= 3 10^-21 m^-2. Interpreting k as a cosmological constant \Lambda, it turns
out that such constraints are weaker than those obtained from the
Schwarzschild-de Sitter metric.


title: Distribution of complexities in the Vai script

abstract:
  In the paper, we analyze the distribution of complexities in the Vai script,
an indigenous syllabic writing system from Liberia. It is found that the
uniformity hypothesis for complexities fails for this script. The models using
Poisson distribution for the number of components and hyper-Poisson
distribution for connections provide good fits in the case of the Vai script.


title: A Metal-biased Planet Search

abstract:
  We have begun a metal-rich planet search project using the HARPS instrument
in La Silla, Chile to target planets with a high potential to transit their
host star and add to the number of bright benchmark transiting planets. The
sample currently consists of 100, bright (7.5 </= V </= 9.5) solar-type stars
(0.5 </= B-V </= 0.9) in the southern hemisphere which are both inactive
(logR'HK </= -4.5) and metal-rich ([Fe/H] >/= 0.1 dex). We determined the
chromospheric activity and metallicity status of our sample using high
resolution FEROS spectra. We also introduce the first result from our HARPS
planet search and show that the radial-velocity amplitude of this star is
consistent with an orbiting planetary-mass companion (i.e. Msini < 0.5MJ) with
a period of ~5 days. We are currently engaged in follow-up to confirm this
signal as a bonafide orbiting planet.


title: High-energy emission from microqusars

abstract:
  If the jets of microquasars carry a significant power in the form of
relativistic hadrons, then gamma rays and neutrinos can be produced by
interactions with matter and photon fields either external or internal to the
jet. In this paper I present some recent results of calculations of the
interaction of hadronic jets with 1) matter of the jet itself, 2) photon fields
generated by synchrotron radiation of both protons and electrons, and 3) matter
external to the jet (e.g. a clumped wind). I briefly discuss neutrino
production in these scenarios and the prospects of detection with new gamma-ray
instruments. Finally, I make a few comments on the controversy about the nature
of LS I +61 303.


title:
Corotational Instability of Inertial-Acoustic Modes in Black Hole
  Accretion Discs and Quasi-Periodic Oscillations

abstract:
  We study the global stability of non-axisymmetric p-modes (also called
inertial-acoustic modes) trapped in the inner-most regions of accretion discs
around black holes. We show that the lowest-order (highest-frequency) p-modes,
with frequencies $\omega=(0.5-0.7) m\Omega_{\rm ISCO}$, can be overstable due
to general relativistic effects, according to which the radial epicyclic
frequency is a non-monotonic function of radius near the black hole. The mode
is trapped inside the corotation resonance radius and carries a negative
energy. The mode growth arises primarily from wave absorption at the corotation
resonance, and the sign of the wave absorption depends on the gradient of the
disc vortensity. When the mode frequency is sufficiently high, such that the
slope of the vortensity is positive at corotation positive wave energy is
absorbed at the resonance, leading to the growth of mode amplitude. We also
study how the rapid radial inflow at the inner edge of the disc affects the
mode trapping and growth. Our analysis of the behavior of the fluid
perturbations in the transonic flow near the ISCO indicates that, while the
inflow tends to damp the mode, the damping effect is sufficiently small under
some conditions so that net mode growth can still be achieved. We further
clarify the role of the Rossby wave instability and show that it does not
operate for black hole accretion discs with smooth-varying vortensity profiles.
Overstable non-axisymmetric p-modes driven by the corotational instability
provide a plausible explanation for the high-frequency (> 100 Hz)
quasi-periodic oscillations (HFQPOs) observed from a number of black-hole X-ray
binaries in the very high state. The absence of HFQPOs in the soft (thermal)
state may result from mode damping due to the radial infall at the ISCO.


abstract:
  The nuclear star cluster of the Milky Way is a unique target in the Universe.
Contrary to extragalactic nuclear star clusters, using current technology it
can be resolved into tens of thousands of individual stars. This allows us to
study in detail its spatial and velocity structure as well as the different
stellar populations that make up the cluster. Moreover, the Milky Way is one of
the very few cases where we have firm evidence for the co-existence of a
nuclear star cluster with a central supermassive black hole, Sagittarius A*.
The number density of stars in the Galactic center nuclear star cluster can be
well described, at distances $\gtrsim1$ pc from Sagittarius A*, by a power-law
of the form $\rho(r)\propto r^{-\gamma}$ with an index of $\gamma\approx1.8$.
In the central parsec the index of the power-law becomes much flatter and
decreases to $\gamma\approx1.2$. We present proper motions for more than 6000
stars within 1 pc in projection from the central black hole. The cluster
appears isotropic at projected distances $\gtrsim0.5$ pc from Sagittarius A*.
Outside of 0.5 pc and out to 1.0 pc the velocity dispersion appears to stay
constant. A robust result of our Jeans modeling of the data is the required
presence of $0.5-2.0\times10^{6} M_{\odot}$ of extended (stellar) mass in the
central parsec of the Galaxy.


title:
Galactic abundance gradients from Cepheids : On the iron abundance
  gradient around 10-12 kpc

abstract:
  Context: Classical Cepheids can be adopted to trace the chemical evolution of
the Galactic disk since their distances can be estimated with very high
accuracy. Aims: Homogeneous iron abundance measurements for 33 Galactic
Cepheids located in the outer disk together with accurate distance
determinations based on near-infrared photometry are adopted to constrain the
Galactic iron gradient beyond 10 kpc. Methods: Iron abundances were determined
using high resolution Cepheid spectra collected with three different
observational instruments: ESPaDOnS@CFHT, Narval@TBL and FEROS@2.2m ESO/MPG
telescope. Cepheid distances were estimated using near-infrared (J,H,K-band)
period-luminosity relations and data from SAAO and the 2MASS catalog. Results:
The least squares solution over the entire data set indicates that the iron
gradient in the Galactic disk presents a slope of -0.052+/-0.003 dex/kpc in the
5-17 kpc range. However, the change of the iron abundance across the disk seems
to be better described by a linear regime inside the solar circle and a
flattening of the gradient toward the outer disk (beyond 10 kpc). In the latter
region the iron gradient presents a shallower slope, i.e. -0.012+/-0.014
dex/kpc. In the outer disk (10-12 kpc) we also found that Cepheids present an
increase in the spread in iron abundance. Current evidence indicates that the
spread in metallicity depends on the Galactocentric longitude. Finally, current
data do not support the hypothesis of a discontinuity in the iron gradient at
Galactocentric distances of 10-12 kpc. Conclusions: The occurrence of a spread
in iron abundance as a function of the Galactocentric longitude indicates that
linear radial gradients should be cautiously treated to constrain the chemical
evolution across the disk.


title: On real analytic Banach manifolds

abstract:
  Let $X$ be a real Banach space with an unconditional basis (e.g., $X=\ell_2$
Hilbert space), $\Omega\subset X$ open, $M\subset\Omega$ a closed split real
analytic Banach submanifold of $\Omega$, $E\to M$ a real analytic Banach vector
bundle, and ${\Cal A}^E\to M$ the sheaf of germs of real analytic sections of
$E\to M$. We show that the sheaf cohomology groups $H^q(M,{\Cal A}^E)$ vanish
for all $q\ge1$, and there is a real analytic retraction $r:U\to M$ from an
open set $U$ with $M\subset U\subset\Omega$ such that $r(x)=x$ for all $x\in
M$. Some applications are also given, e.g., we show that any infinite
dimensional real analytic Hilbert submanifold of separable affine or projective
Hilbert space is real analytically parallelizable.


title:
The importance of an accurate target wave function in variational
  calculations for (e^{+}-H_{2}) scattering

abstract:
  Using the complex Kohn method, we have calculated variational values of phase
shifts and the annihilation parameter, Z_{eff}, for the elastic scattering of
positrons by molecular hydrogen. Our results are sensitive to small changes in
the accuracy of the wave function representing the target hydrogen molecule. We
have developed a systematic approach to demonstrate that, at low positron
energies, there are particular forms of the Kohn trial wave function for which
the results of variational calculations are not reliable, even when the target
wave function accounts for as much as 96.8% of the correlation energy of H_{2}.
We find that reliable results can be recovered if our calculations are extended
to admit more sophisticated target wave functions accounting for 99.7% of the
correlation energy. Remaining discrepancies between theory and experiment are
briefly discussed.


title: A General Analysis of Non-Gaussianity from Isocurvature Perturbations

abstract:
  Light scalars may be ubiquitous in nature, and their quantum fluctuations can
produce large non-Gaussianity in the cosmic microwave background temperature
anisotropy. The non-Gaussianity may be accompanied with a small admixture of
isocurvature perturbations, which often have correlations with the curvature
perturbations. We present a general method to calculate the non-Gaussianity in
the adiabatic and isocurvature perturbations with and without correlations, and
see how it works in several explicit examples. We also show that they leave
distinct signatures on the bispectrum of the cosmic microwave background
temperature fluctuations.


title: $L^p$ spectral theory and heat dynamics of locally symmetric spaces

abstract:
  In this paper we first derive several results concerning the $L^p$ spectrum
of arithmetic locally symmetric spaces whose $\Q$-rank equals one. In
particular, we show that there is an open subset of $\C$ consisting of
eigenvalues of the $L^p$ Laplacian if $p <2$ and that corresponding
eigenfunctions are given by certain Eisenstein series. On the other hand, if
$p>2$ there is at most a discrete set of real eigenvalues of the $L^p$
Laplacian. These results are used in the second part of this paper in order to
show that the dynamics of the $L^p$ heat semigroups for $p<2$ is very different
from the dynamics of the $L^p$ heat semigroups if $p\geq 2$.


title: Finite Temperature Models of Bose-Einstein Condensation

abstract:
  The theoretical description of trapped weakly-interacting Bose-Einstein
condensates is characterized by a large number of seemingly very different
approaches which have been developed over the course of time by researchers
with very distinct backgrounds. Newcomers to this field, experimentalists and
young researchers all face a considerable challenge in navigating through the
`maze' of abundant theoretical models, and simple correspondences between
existing approaches are not always very transparent. This Tutorial provides a
generic introduction to such theories, in an attempt to single out common
features and deficiencies of certain `classes of approaches' identified by
their physical content, rather than their particular mathematical
implementation.
  This Tutorial is structured in a manner accessible to a non-specialist with a
good working knowledge of quantum mechanics. Although some familiarity with
concepts of quantum field theory would be an advantage, key notions such as the
occupation number representation of second quantization are nonetheless briefly
reviewed. Following a general introduction, the complexity of models is
gradually built up, starting from the basic zero-temperature formalism of the
Gross-Pitaevskii equation. This structure enables readers to probe different
levels of theoretical developments (mean-field, number-conserving and
stochastic) according to their particular needs. In addition to its `training
element', we hope that this Tutorial will prove useful to active researchers in
this field, both in terms of the correspondences made between different
theoretical models, and as a source of reference for existing and developing
finite-temperature theoretical models.


title: Planar aggregation and the coalescing Brownian flow

abstract:
  We study a scaling limit associated to a model of planar aggregation. The
model is obtained by composing certain independent random conformal maps. The
evolution of harmonic measure on the boundary of the cluster is shown to
converge to the coalescing Brownian flow.


title:
Galactic Rotation Curve and the Effect of Density Waves from Data on
  Young Objects

abstract:
  Based on currently available data on the three-dimensional field of space
velocities of young (<50 Myr) open star clusters and the radial velocities of
HI clouds and star-forming (HII) regions, we have found the Galactic rotation
curve in the range of Galactocentric distances 3 kpc <R<12 kpc using the first
six terms of the Taylor expansion of the angular velocity of Galactic rotation
in Bottlinger's equations. The Oort constants found are
  A= 15.5+-0.3 km/s/kpc and B=-12.2+-0.7 km/s/kpc. We have established that the
centroid of the sample moves relative to the local standard of rest along the
Galactic Y axis with a velocity of -6.2+-0.8 km/s. A Fourier spectral analysis
of the velocity residuals from the derived rotation curve attributable to
density waves reveals three dominant peaks with wavelengths of 2.5, 1.4, and
0.9 kpc and amplitudes of 4.7, 2.6, and 3.6 km/s, respectively. These have
allowed us to estimate the distances between the density wave peaks, 1.9, 2.4,
and 3.2 kpc as R increases, in agreement with the description of the density
weave as a logarithmic spiral. The amplitude of the density wave perturbations
is largest in the inner part of the Galaxy, about 9 km/s, and decreases to
approximately 1 km/s in its outer part. A spectral analysis of the radial
velocities of young open star clusters has confirmed the presence of periodic
perturbations with an amplitude of 5.9+-1.1 km/s and a wavelength 1.7+-0.5 kpc.
It shows that the phase of the Sun in the density wave is close to -90 degrees
and the Sun is located in the interarm space near the outer edge of the
Carina-Sagittarius arm.


title: Influence of coaxial cylinders on vortex breakdown in a closed flow

abstract:
  The effect of fixed cylindrical rods located at the centerline axis on vortex
breakdown (VB) is studied experimentally and numerically. We find that the VB
is enhanced for very small values of the rod radius $d$, while it is suppressed
for values of $d$ beyond a critical value. In order to characterize this
effect, the critical Reynolds number for the appearance of vortex breakdown as
a function of the radius of the fixed rods and the different aspect ratios was
accurately determined, using digital particle image velocimetry. The numerical
and experimental results are compared showing an excellent agreement. In
addition, a simple model in order to show that this effect also appears in open
pipe flows is presented in the appendix.


title: $D_s$ physics from fine lattices

abstract:
  We present a preliminary analysis of the charm quark mass and the mass and
decay constant $f_{D_s}$ of the $D_s$ meson obtained from dynamical simulations
of $N_f = 2$ Wilson QCD on the large and fine lattices simulated by the CLS
effort.


title: The root closure of a ring of mixed characteristic

abstract:
  We define a closure operation for rings of mixed characteristic and verify
that the closure is a ring. We then show that this closure produces a ring with
good properties with respect to its Fontaine ring and give an example to show
that rings that are not closed in this sense do not satisfy these properties.


title:
Fractal geometry of Ising magnetic patterns: signatures of criticality
  and diffusive dynamics

abstract:
  We investigate the geometric properties displayed by the magnetic patterns
developing on a two-dimensional Ising system, when a diffusive thermal dynamics
is adopted. Such a dynamics is generated by a random walker which diffuses
throughout the sites of the lattice, updating the relevant spins. Since the
walker is biased towards borders between clusters, the border-sites are more
likely to be updated with respect to a non-diffusive dynamics and therefore, we
expect the spin configurations to be affected. In particular, by means of the
box-counting technique, we measure the fractal dimension of magnetic patterns
emerging on the lattice, as the temperature is varied. Interestingly, our
results provide a geometric signature of the phase transition and they also
highlight some non-trivial, quantitative differences between the behaviors
pertaining to the diffusive and non-diffusive dynamics.


title:
Open Clusters IC 4665 and Cr 359 and a Probable Birthplace of the Pulsar
  PSR B1929+10

abstract:
  Based on the epicyclic approximation, we have simulated the motion of the
young open star clusters IC 4665 and Collinder 359. The separation between the
cluster centers is shown to have been minimal 7 Myr ago, 36 pc. We have
established a close evolutionary connection between IC 4665 and the
Scorpius-Centaurus association -- the separation between the centers of these
structures was $\approx200$ pc 15 Myr ago. In addition, the center of IC 4665
at this time was near two well-known regions of coronal gas: the Local Bubble
and the North Polar Spur. The star HIP 86768 is shown to be one of the
candidates for a binary (in the past) with the pulsar PSR B1929+10. At the
model radial velocity of the pulsar $V_r= 2\pm50$ km s$^{-1}$, a close
encounter of this pair occurs in the vicinity of IC 4665 at a time of -1.1 Myr.
At the same time, using currently available data for the pulsar B1929+10 at its
model radial velocity $V_r=200\pm50$ km s$^{-1}$, we show that the hypothesis
of Hoogerwerf et al. (2001) about the breakup of the $\zeta$Oph--B1929+10
binary in the vicinity of Upper Scorpius (US) about 0.9 Myr ago is more
plausible.


title: B-Reconstruction Methods via Geometro-Kinematic Constraints (I)

abstract:
  Decay channels with attractive branching ratios, or interesting physics, are
recovered by substituting missing particles (nu, pi0, etc) with combined
geometric and kinematic constraints. The Sliding Vertex method is shown in this
part-I, for reconstructing strongly boosted B0s decays - at the LHC.


title:
Bi-partite entanglement entropy in massive QFT with a boundary: the
  Ising model

abstract:
  In this paper we give an exact infinite-series expression for the bi-partite
entanglement entropy of the quantum Ising model both with a boundary magnetic
field and in infinite volume. This generalizes and extends previous results
involving the present authors for the bi-partite entanglement entropy of
integrable quantum field theories, which exploited the generalization of the
form factor program to branch-point twist fields. In the boundary case, we
isolate in a universal way the part of the entanglement entropy which is
related to the boundary entropy introduced by Affleck and Ludwig, and explain
how this relation should hold in more general QFT models. We provide several
consistency checks for the validity of our form factor results, notably, the
identification of the leading ultraviolet behaviour both of the entanglement
entropy and of the two-point function of twist fields in the bulk theory, to a
great degree of precision by including up to 500 form factor contributions.


title: On a continuous time game with incomplete information

abstract:
  For zero-sum two-player continuous-time games with integral payoff and
incomplete information on one side, one shows that the optimal strategy of the
informed player can be computed through an auxiliary optimization problem over
some martingale measures. One also characterizes the optimal martingale
measures and compute it explicitely in several examples.


title: Time dependent modelisation of TeV blazars by a stratified jet model

abstract:
  We present a new time-dependent inhomogeneous jet model of non-thermal blazar
emission. Ultra-relativistic leptons are injected at the base of a jet and
propagate along it. We assume continuous reacceleration and cooling, producing
a relativistic quasi-maxwellian (or "pile-up") particle energy distribution.
The synchrotron and Synchrotron-Self Compton jet emissivity are computed at
each altitude. Klein-Nishina effects as well as intrinsic gamma-gamma
absorption are included in the computation. Due to the pair production optical
depth, considerable particle density enhancement can occur, particularly during
flaring states.Time-dependent jet emission can be computed by varying the
particle injection, but due to the sensitivity of pair production process, only
small variations of the injected density are required during the flares. The
stratification of the jet emission, together with a pile-up distribution,
allows significantly lower bulk Lorentz factors, compared to one-zone models.
Applying this model to the case of PKS 2155-304 and its big TeV flare observed
in 2006, we can reproduce simultaneously the average broad band spectrum of
this source from radio to TeV, as well as TeV light curve of the flare with
bulk Lorentz factor lower than 15.


title: A note on Sierpi\'{n}ski problem related to triangular numbers

abstract:
  In this note we show that the system of equations t_{x}+t_{y}=t_{p},\quad
t_{y}+t_{z}=t_{q},\quad t_{x}+t_{z}=t_{r}, where $t_{x}=x(x+1)/2$ is a
triangular number, has infinitely many solutions in integers. Moreover we show
that this system has rational three-parametric solution. Using this result we
show that the system t_{x}+t_{y}=t_{p},\quad t_{y}+t_{z}=t_{q},\quad
t_{x}+t_{z}=t_{r},\quad t_{x}+t_{y}+t_{z}=t_{s} has infinitely many rational
two-parametric solutions.


title:
Differential operators on an affine curve: ideal classes and Picard
  groups

abstract:
  Let X be a smooth complex affine curve, and let R be the space of right ideal
classes in the ring D of differential operators on X. We introduce and study a
fibration \gamma : R \to Pic(X). We relate this fibration to the corresponding
one in the classical limit, and derive an integer invariant $ n $ which indexes
the decomposition of the fibres of \gamma into Calogero-Moser spaces (see
[BC]). We also study the action of the group Pic(D) on our fibration; and we
explain how to define \gamma in the framework of the Grassmannian description
of R due to Cannings and Holland.


title: What is vacuum?

abstract:
  Vacuum can be defined with exact mathematical precision as the state which
remains when a fermion, with all its special characteristics, is created out of
absolutely nothing. The definition leads to a special form of relativistic
quantum mechanics, which only requires the construction of a creation operator.
This form of quantum mechanics is especially powerful for analytic calculation,
at the same time as explaining, from first principles, many aspects of the
Standard Model of particle physics. In particular, the characteristics of the
weak, strong and electric interactions can be derived from the structure of the
creation operator itself.


title: Rational points on certain quintic hypersurfaces

abstract:
  Let $f(x)=x^5+ax^3+bx^2+cx \in \Z[x]$ and consider the hypersurface of degree
five given by the equation \cal{V}_{f}: f(p)+f(q)=f(r)+f(s). Under the
assumption $b\neq 0$ we show that there exists $\Q$-unirational elliptic
surface contained in $\cal{V}_{f}$. If $b=0, a<0$ and $-a\not\equiv 2,18,34
\pmod {48}$ then there exists $\Q$-rational surface contained in $\cal{V}_{f}$.
Moreover, we prove that for each $f$ of degree five there exists
$\Q(i)$-rational surface contained in $\cal{V}_{f}$.


title: Generalized Maximum Likelihood Method for Ultrahigh Energy Cosmic Rays

abstract:
  The Maximum Likelihood Method is generalized to include effects important for
UHECR applications. The new approach can incorporate source distance
constraints implied by the observed CR energy and can allow for energy
uncertainties, possible deflection in magnetic fields, multiple source types,
and a spectrum of CR composition. It can be efficiently implemented and does
not require the unphysical "isotropic" assumption for unidentified sources. The
approach optimizes the utility of UHECR data to discriminate between source
classes and can help constrain galactic and extragalactic magnetic fields.
Aspects of the method are directly applicable in other contexts, such as TeV
gamma ray astrophysics.


title: Non-relativistic Holography and Singular Black Hole

abstract:
  We provide a framework for non-relativistic holography so that a covariant
action principle ensuring the Galilean symmetry for dual conformal field theory
is given. This framework is based on the Bargmann lift of the Newton-Cartan
gravity to the one-dimensional higher Einstein gravity, or reversely, the
null-like Kaluza-Klein reduction. We reproduce the previous zero temperature
results, and our framework provides a natural explanation about why the
holography is co-dimension 2. We then construct the black hole solution dual to
the thermal CFT, and find the horizon is curvature singular. However, we are
able to derive the sensible thermodynamics for the dual non-relativistic CFT
with correct thermodynamical relations. Besides, our construction admits a null
Killing vector in the bulk such that the Galilean symmetry is preserved under
the holographic RG flow. Finally, we evaluate the viscosity and find it zero if
we neglect the back reaction of the singular horizon, otherwise, it could be
nonzero.


title: Slow nucleation rates in Chain Inflation with QCD Axions or Monodromy

abstract:
  The previous proposal (by two of us) of chain inflation with the QCD axion is
shown to fail. The proposal involved a series of fast tunneling events, yet
here it is shown that tunneling is too slow. We calculate the bubble nucleation
rates for phase transitions in the thick wall limit, approximating the barrier
by a triangle. A similar problem arises in realization of chain inflation in
the string landscape that uses series of minima along the monodromy staircase
around the conifold point. The basic problem is that the minima of the
potential are too far apart to allow rapid enough tunneling in these two
models. We entertain the possibility of overcoming this problem by modifying
the gravity sector to a Brans-Dicke theory. However, one would need extremely
small values for the Brans-Dicke parameter. Many successful alternatives exist,
including other "axions" (with mass scales not set by QCD) or potentials with
comparable heights and widths that do not suffer from the problem of slow
tunneling and provide successful candidates for chain inflation.


title: Reciprocity laws \`a la Iwasawa-Wiles

abstract:
  This paper is a brief survey on explicit reciprocity laws of
Artin-Hasse-Iwasawa-Wiles type for the Kummer pairing on local fields.


title: Tensor products of recurrent hypercyclic semigroups

abstract:
  We study tensor products of strongly continuous semigroups on Banach spaces
that satisfy the hypercyclicity criterion, the recurrent hypercyclicity
criterion or are chaotic.


title: Spontaneous Emission in ultra-cold spin-polarised anisotropic Fermi Seas

abstract:
  We examine and explain the spatial emission patterns of ultracold excited
fermions in anisotropic trapping potentials in the presence of a spin polarised
Fermi sea of ground state atoms. Due to the Pauli principle, the Fermi sea
modifies the available phase space for the recoiling atom and thereby modifies
its decay rate and the probability of the emitted photon's direction. We show
that the spatial anisotropies are due to an intricate interplay between Fermi
energies and degeneracy values of specific energy levels and identify a regime
in which the emission will become completely directional. Our results are
relevant for recent advances in trapping and manipulating cold fermionic
samples experimentally and give an example of a conceptually new idea for a
directional photon source.


title: Study of Rare Exclusive Electroweak Processes at HERA

abstract:
  Results on multi-lepton events at high transverse momenta, isolated lepton
events with large missing transverse energy and single W production reported to
this conference are based for the first time on the full data samples taken by
two colliding experiments, H1 and ZEUS, at HERA. The data correspond to an
integrated luminosity of about 1fb-1 from both experiments.


title:
Adaptation and Performance of the Cartesian Coordinates Fast Multipole
  Method for Nanomagnetic Simulations

abstract:
  An implementation of the fast multiple method (FMM) is performed for magnetic
systems with long-ranged dipolar interactions. Expansion in spherical harmonics
of the original FMM is replaced by expansion of polynomials in Cartesian
coordinates, which is considerably simpler. Under open boundary conditions, an
expression for multipole moments of point dipoles in a cell is derived. These
make the program appropriate for nanomagnetic simulations, including magnetic
nanoparticles and ferrofluids. The performance is optimized in terms of cell
size and parameter set (expansion order and opening angle) and the trade off
between computing time and accuracy is quantitatively studied. A rule of thumb
is proposed to decide the appropriate average number of dipoles in the smallest
cells, and an optimal choice of parameter set is suggested. Finally, the
superiority of Cartesian coordinate FMM is demonstrated by comparison to
spherical harmonics FMM and FFT.


title: Integer Knapsacks: Average Behavior of the Frobenius Numbers

abstract:
  The main result of the paper shows that the asymptotic growth of the
Frobenius number in average is significantly slower than the growth of the
maximum Frobenius number.


title: Generic tripartite Bell nonlocality sudden death under local phase noise

abstract:
  We definitively show, using an explicit and broadly applicable model, that
local phase noise that is capable of eliminating state coherence only in the
infinite-time limit is capable of eliminating nonlocality in finite time in
three two-level systems prepared in the Bell-nonlocal tripartite states of the
generic entanglement class.


title: Controlling the Kondo Effect in CoCu_n Clusters Atom by Atom

abstract:
  Clusters containing a single magnetic impurity were investigated by scanning
tunneling microscopy, spectroscopy, and ab initio electronic structure
calculations. The Kondo temperature of a Co atom embedded in Cu clusters on
Cu(111) exhibits a non-monotonic variation with the cluster size. Calculations
model the experimental observations and demonstrate the importance of the local
and anisotropic electronic structure for correlation effects in small clusters.


title:
Mass estimate of the XTE J1650-500 black hole from the Extended Orbital
  Resonance Model for high-frequency QPOs

abstract:
  XTE J1650-500 is a Galactic black-hole binary system for which at least one
high-frequency QPO at 250Hz was reported. Moreover there are indications that
the system harbours a near-extreme Kerr black-hole with the spin near 0.998 and
mass M<7.3M_sun. Recently it was discovered that the orbital 3-velocity of
Keplerian (geodesical) discs orbiting Kerr black holes with the spin a>0.9953,
being analyzed in the locally non-rotating frames, reveals a hump near the
marginally stable orbit. Further it was suggested that the hump could excite
the epicyclic motion of particles near the ISCO with frequencies typical for
high-frequency QPOs. Characteristic frequency of the hump-induced oscillations
was defined as the maximal positive rate of change of the LNRF-related orbital
velocity with the proper radial distance. If the characteristic "humpy
frequency" and the radial epicyclic frequency are commensurable, strong
resonant phenomena are expected. For the Kerr black hole with the spin a=0.9982
the "humpy frequency" and the radial epicyclic frequency are in ratio 1:3.
Identifying the radial epicyclic frequency with the observed 250Hz QPO, we get
the mass of the black hole in XTE J1650-500 near 5.1M_sun.


title: Complete WKB asymptotics of high frequency vibrations in a stiff problem

abstract:
  Asymptotic behaviour of eigenvalues and eigenfunctions of a stiff problem is
described in the case of the fourth-order ordinary differential operator.
Considering the stiffness coefficient that depends on a small parameter epsilon
and vanishes as epsilon tends to zero on a subinterval, we prove the existence
of low and high frequency resonance vibrations. The low frequency vibrations
admit the power series expansions on epsilon but this method is not applicable
to the description of high frequency vibrations. However, the nonclassical
asymptotics on epsilon of the high frequency vibrations were constructed using
the WKB method.


title:
Stochastic models and numerical algorithms for a class of regulatory
  gene networks

abstract:
  Regulatory gene networks contain generic modules like those involving
feedback loops, which are essential for the regulation of many biological
functions. We consider a class of self-regulated genes which are the building
blocks of many regulatory gene networks, and study the steady state
distributions of the associated Gillespie algorithm by providing efficient
numerical algorithms. We also study a regulatory gene network of interest in
synthetic biology and in gene therapy, using mean-field models with time
delays. Convergence of the related time-nonhomogeneous Markov chain is
established for a class of linear catalytic networks with feedback loops


title: Contact process on a Voronoi triangulation

abstract:
  We study the continuous absorbing-state phase transition in the contact
process on the Voronoi-Delaunay lattice. The Voronoi construction is a natural
way to introduce quenched coordination disorder in lattice models. We simulate
the disordered system using the quasistationary simulation method and determine
its critical exponents and moment ratios. Our results suggest that the critical
behavior of the disordered system is unchanged with respect to that on a
regular lattice, i.e., that of directed percolation.


title:
Hydrostatic pressure study of the structural phase transitions and
  superconductivity in single crystals of (Ba1-xKx)Fe2As2 (x = 0 and 0.45) and
  CaFe2As2

abstract:
  We studied the effect of hydrostatic pressure (P) on the structural phase
transitions and superconductivity in the ternary and pseudo-ternary iron
arsenides CaFe2As2, BaFe2As2, and (Ba0.55K0.45)Fe2As2, by means of measurements
of electrical resistivity (rho) in the 1.8 - 300 K temperature (T) range,
pressures up to 20 kbar, and magnetic fields up to 9 T. CaFe2As2 and BaFe2As2
(lightly doped with Sn) display structural phase transitions near 170 K and 85
K, respectively, and do not exhibit superconductivity in ambient pressure,
while K-doped (Ba0.55K0.45)Fe2As2 is superconducting for T < 30 K. The effect
of pressure on BaFe2As2 is to shift the onset of the crystallographic
transformation down in temperature at the rate of about -1.04 K/kbar, while
shifting the whole rho(T) curves downward, whereas its effect on
superconducting (Ba0.55K0.45)Fe2As2 is to shift the onset of superconductivity
to lower temperatures at the rate of about -0.21 K/kbar. The effect of pressure
on CaFe2As2 is first to suppress the crystallographic transformation and induce
superconductivity with onset near 12 K very rapidly, i.e., for P < 5 kbar.
However, higher pressures bring about another phase transformation
characterized by reduced resistivity, and the suppression of superconductivity,
confining superconductivity to a narrow pressure dome centered near 5 kbar.
Upper critical field (Hc2) data in (Ba0.55K0.45)Fe2As2 and CaFe2As2 are
discussed.


title:
On a preseismic electric field "strange attractor" like precursor
  observed short before large earthquakes

abstract:
  The Earth's electric field, recorded by two different and distant monitoring
sites located in Greece, is analyzed in terms of monochromatic signals (T=24h).
The analysis is based on the mapping procedures borrowed from the study of
non-linear dynamic systems and chaos. The specific analysis applied on the
electric field recorded for some weeks before the occurrence of 3 large EQs
which occurred in Greece shows some very interesting results. Long before the
EQ occurrence the phase map generated by the uncorrelated each other signals
recorded by a pair of distant monitoring sites is characterized by pairs of
hyperbolas of random azimuth asymptotes. Some days before the occurrence of the
earthquake the recorded signals are strongly correlated and therefore the phase
map is characterized by ellipses. A couple of days before the EQ occurrence the
electric signals become again uncorrelated due to the fact that their
generating mechanism (large scale piezoelectricity) approaches its final stage
and therefore hyperbolas characterize again the phase map. When this stage is
observed the pending EQ shortly (in terms of days) takes place. Three detailed
examples from large Greek EQs are presented towards the validation of this
mechanism.


title: Tube dislocations in gravity

abstract:
  We consider static massive thin cylindrical shells (tubes) as the sources in
Einstein's equations. They correspond to $\dl$- and $\dl'$-function type
energy-momentum tensors. The corresponding metric components are found
explicitly. They are not continuous functions in general and lead to ambiguous
curvature tensor components. Nevertheless all ambiguous terms in Einstein's
equations safely cancel. The interplay between elasticity theory, geometric
theory of defects, and General Relativity is analyzed. The elasticity theory
provides a simple picture for defects creation and a new look on General
Relativity.


title: Mass-losing accretion discs around supermassive black holes

abstract:
  We study the effects of outflow/wind on the gravitational stability of
accretion discs around supermassive black holes using a set of analytical
steady-state solutions. Mass-loss rate by the outflow from the disc is assumed
to be a power-law of the radial distance and the amount of the energy and the
angular momentum which are carried away by the wind are parameterized
phenomenologically. We show that the mass of the first clumps at the
self-gravitating radius linearly decreases with the total mass-loss rate of the
outflow. Except for the case of small viscosity and high accretion rate,
generally, the self-gravitating radius increases as the amount of mass-loss by
the outflow increases. Our solutions show that as more angular momentum is lost
by the outflow, then reduction to the mass of the first clumps is more
significant.


title:
Resonantly suppressed transmission and anomalously enhanced light
  absorption in ultrathin metal films

abstract:
  We study light diffraction in the periodically modulated ultrathin metal
films both analytically and numerically. Without modulation these films are
almost transparent. The periodicity results in the anomalous effects, such as
suppression of the transmittance accompanied by a strong enhancement of the
absorptivity and specular reflectivity, due to excitation of the surface
plasmon polaritons. These phenomena are opposite to the widely known enhanced
transparency of periodically modulated optically thick metal films. Our
theoretical analysis can be a starting point for the experimental investigation
of these intriguing phenomena.


title:
Dust Settling in Magnetorotationally-Driven Turbulent Discs I: Numerical
  Methods and Evidence for a Vigorous Streaming Instability

abstract:
  (Abridged) In this paper we have used the RIEMANN code for computational
astrophysics to study the interaction of a realistic distribution of dust
grains with gas in a vertically stratified protostellar accretion disc. The
disc was modeled to have the density and temperature of a minimum mass solar
nebula, and was driven to a fully-developed turbulence via the
magnetorotational instability (MRI). We find that the inclusion of standard
dust to gas ratios does not have any significant effect on the MRI even when
the dust sediments to the midplane of the accretion disc. The density
distribution of the dust reaches a Gaussian profile, and the scale heights for
the dust that we derive are shown to be proportional to the reciprocal of the
square root of the dust radius. The largest dust shows a strong tendency to
settle to the midplane of the accretion disc, and tends to organize itself into
elongated clumps of high density. The dynamics of these clumps is shown to be
consistent with a streaming instability. The streaming instability is seen to
be very vigorous and persistent once it forms. Each stream of high density dust
displays a reduced RMS velocity dispersion, and the densest clumpings of large
dust are shown to form where the streams intersect. We have also shown that the
mean free path and collision time for the dust that participates in the
streaming instability is reduced by almost two orders of magnitude relative to
the average mean free paths and collision times. We show that some of the large
dust in our 10 au simulations should have a propensity for grain coalescence.


title: Reconstructing Fourier's law from disorder in quantum wires

abstract:
  The theory of open quantum systems is used to study the local temperature and
heat currents in metallic nanowires connected to leads at different
temperatures. We show that for ballistic wires the local temperature is almost
uniform along the wire and Fourier's law is invalid. By gradually increasing
disorder, a uniform temperature gradient ensues inside the wire and the thermal
current linearly relates to this local temperature gradient, in agreement with
Fourier's law. Finally, we demonstrate that while disorder is responsible for
the onset of Fourier's law, the non-equilibrium energy distribution function is
determined solely by the heat baths.


title:
Measurement of the Double Beta Decay Half-life of 150-Nd and Search for
  Neutrinoless Decay Modes with the NEMO-3 Detector

abstract:
  The half-life for double beta decay of 150-Nd has been measured by the NEMO-3
experiment at the Modane Underground Laboratory. Using 924.7 days of data
recorded with 36.55 g of 150-Nd the half-life for 2nubb decay is measured to be
T_1/2^2nu = (9.11+0.25_-0.22}(stat.) +- 0.63 (syst.)) x 10^18 years. The
observed limit on the half-life for neutrinoless double beta decay is found to
be T_1/2^{0nu} > 1.8 x 10^22 years at 90 % Confidence Level. This translates
into a limit on the effective Majorana neutrino mass of <m_{neutrino}><4.0-6.3
eV if the nuclear deformation is taken into account. We also set limits on
models involving Majoron emission, right-handed currents and transitions to
excited states.


title: B -> V_L V_L Decays at Next-to-Leading Order in QCD

abstract:
  We compute the amplitudes for the two-body decay of $B$ mesons into
longitudinally polarized light vector mesons at next-to-leading order in QCD.
We give the explicit expressions in QCD factorization for all 34 transitions of
a heavy-light $B$ meson into a pair of longitudinal vector mesons $\rho$,
$\omega$, $\phi$, $K^*$ within the Standard Model. Decay rates and CP
asymmetries are discussed in detail and compared with available data.
Exploiting the fact that QCD penguins are systematically smaller for vector
mesons in comparison to pseudoscalars in the final state, we investigate
several methods to achieve high-precision determinations of CKM parameters and
New Physics tests. We propose a method to use V-spin symmetry and data on $\bar
B_d\to\bar K^{*0}_L K^{*0}_L$ to constrain the penguin contribution in $\bar
B_d\to\rho^+_L\rho^-_L$. CP violation in the latter decay together with a
measurement of $\sin 2\beta$ determines the unitarity triangle with high
accuracy. We show that CP violation in $\bar B_d\to\rho^+_L\rho^-_L$ and $\bar
B_d\to\psi K_S$ alone implies $|V_{ub}|=(3.54\pm 0.17)\cdot 10^{-3}$, presently
the most accurate determination of this quantity.


title: Veneziano amplitudes, spin chains and Abelian reduction of QCD

abstract:
  Although QCD can be treated perturbatively in the high energy limit, lower
energies requre uses of nonperturbative methods such as ADS/CFT and/or Abelian
reduction.These methods are not equivalent. In this paper we provide arguments
in favor of the Abelian reduction methods. This is achieved by further
developing results of our recent works reanalyzing Veneziano and Veneziano-like
amplitudes and the models associated with these amplitudes. It is shown, that
the obtained new partition function for these amplitudes can be mapped exactly
into that for the Polychronakos-Frahm spin chain model recoverable from the
Richardson-Gaudin XXX spin chain model used originally for treatments of the
BCS-type superconductivity. Because of this, it is demonstrated that the
obtained mapping is compatible with the method of Abelian reduction.


title: Nab: Measurement Principles, Apparatus and Uncertainties

abstract:
  The Nab collaboration will perform a precise measurement of 'a', the
electron-neutrino correlation parameter, and 'b', the Fierz interference term
in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS,
using a novel electric/magnetic field spectrometer and detector design. The
experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will
provide an independent measurement of lambda = G_A/G_V, the ratio of
axial-vector to vector coupling constants of the nucleon. Nab also plans to
perform the first ever measurement of 'b' in neutron decay, which will provide
an independent limit on the tensor weak coupling.


title: Groupoid normalizers of tensor products

abstract:
  We consider an inclusion $B\subseteq M$ of finite von Neumann algebras
satisfying $B'\cap M\subseteq B$. A partial isometry $v\in M$ is called a
groupoid normalizer if $vBv^*, v^*Bv\subseteq B$. Given two such inclusions
$B_i\subseteq M_i$, $i=1,2$, we find approximations to the groupoid normalizers
of $B_1 \vnotimes B_2$ in $M_1\vnotimes M_2$, from which we deduce that the von
Neumann algebra generated by the groupoid normalizers of the tensor product is
equal to the tensor product of the von Neumann algebras generated by the
groupoid normalizers. Examples are given to show that this can fail without the
hypothesis $B_i'\cap M_i\subseteq B_i$, $i=1,2$. We also prove a parallel
result where the groupoid normalizers are replaced by the intertwiners, those
partial isometries $v\in M$ satisfying $vBv^*\subseteq B$ and $v^*v, vv^*\in
B$.


title: Excited nucleon spectrum with two flavors of dynamical fermions

abstract:
  We compute the spectrum of excited nucleons using the anisotropic Wilson
lattice with two flavors of dynamical fermions. Using optimized sets of
operators which transform irreducibly under the octahedral group, matrices of
correlation functions are computed. We apply the variational method to these
matrices to extract excited energy eigenstates. We obtain several states for
each irrep and identify the continuum spin for the lowest-lying states,
including a $J^P={5/2}^-$ state.


title: Large N lattice gauge theory

abstract:
  Wilson loops in large N gauge theory exhibit a weak to strong coupling
transition as the loop is dilated. A multiplicative matrix model captures the
universal behavior associated with this transition. A universal scaling
function is obtained in a double scaling limit. Numerical studies show that
both large N QCD in three dimensions and the SU(N) principal chiral model in
two dimensions are in the same universality class.


title:
Hyperbolic conservation laws on spacetimes. A finite volume scheme based
  on differential forms

abstract:
  We consider nonlinear hyperbolic conservation laws, posed on a differential
(n+1)-manifold with boundary referred to as a spacetime, and in which the
"flux" is defined as a flux field of n-forms depending on a parameter (the
unknown variable). We introduce a formulation of the initial and boundary value
problem which is geometric in nature and is more natural than the vector field
approach recently developed for Riemannian manifolds. Our main assumption on
the manifold and the flux field is a global hyperbolicity condition, which
provides a global time-orientation as is standard in Lorentzian geometry and
general relativity. Assuming that the manifold admits a foliation by compact
slices, we establish the existence of a semi-group of entropy solutions.
Moreover, given any two hypersurfaces with one lying in the future of the
other, we establish a "contraction" property which compares two entropy
solutions, in a (geometrically natural) distance equivalent to the L1 distance.
To carry out the proofs, we rely on a new version of the finite volume method,
which only requires the knowledge of the given n-volume form structure on the
(n+1)-manifold and involves the {\sl total flux} across faces of the elements
of the triangulations, only, rather than the product of a numerical flux times
the measure of that face.


title: Long range Coulomb interaction in the ground state of bilayer graphene

abstract:
  We report on our studies of interacting electrons in bilayer graphene in a
magnetic field. We demonstrate that the long range Coulomb interactions between
electrons in this material are highly important. We show that in the unbiased
bilayer (where both layers are at the same electrostatic potential), the
interactions can cause mixing of Landau levels in moderate magnetic fields. For
the biased bilayer (when the two layers are at different potentials), we
demonstrate that the interactions are responsible for a change in the total
spin of the ground state for half-filled Landau levels in the valence band.


title:
Limiting distributions and large deviations for random walks in random
  environments

abstract:
  This thesis concerns the study of random walks in random environments (RWRE).
Since there are two levels of randomness for random walks in random
environments, there are two different distributions for the random walk that
can be studied. The quenched distribution is the law of the random walk
conditioned on a given environment. The annealed distribution is the quenched
law averaged over all environments. The main results of the thesis fall into
two categories: quenched limiting distributions for one-dimensional, transient
RWRE and annealed large deviations for multidimensional RWRE.
  The analysis of the quenched distributions for transient, one-dimensional
RWRE falls into two separate cases. First, when an annealed central limit
theorem holds, we prove that a quenched central limit theorem also holds but
with a random (depending on the environment) centering. In contrast, when the
annealed limit distribution is not Gaussian, we prove that there is no quenched
limiting distribution for the RWRE. Moreover, we show that for almost every
environment, there exist two random (depending on the environment) sequences of
times, along which random walk has different quenched limiting distributions.
  While an annealed large deviation principle for multidimensional RWRE was
known previously, very little qualitative information was available about the
annealed large deviation rate function. We prove that if the law on
environments is non-nestling, then the annealed large deviation rate function
is analytic in a neighborhood of its unique zero (which is the limiting
velocity of the RWRE).


title: On temperature dependence of quarkonium correlators

abstract:
  I discuss the temperature dependence of quarkonium correlators calculated in
lattice QCD. I show that the dominant source of the temperature dependence
comes from the zero mode contribution, while the the temperature dependence
associated with melting of bound states is quite small. I study the zero mode
contribution quantitatively for different quark masses and show that it is well
described by a quasi-particle model with temperature dependent heavy quark
mass. As a byproduct an estimate of the medium dependence of the heavy quark
mass is obtained.


title: The GHZ state in secret sharing and entanglement simulation

abstract:
  In this note, we study some properties of the GHZ state. First, we present a
quantum secret sharing scheme in which the participants require only classical
channels in order to reconstruct the secret; our protocol is significantly more
efficient than the trivial usage of teleportation. Second, we show that the
classical simulation of an n-party GHZ state requires at least n log n - 2n
bits of communication. Finally, we present a problem simpler than the complete
simulation of the multi-party GHZ state, that could lead to a no-go theorem for
GHZ state simulation.


title: Independent confirmation and refined parameters of the hot Jupiter XO-5b

abstract:
  We present HATNet observations of XO-5b, confirming its planetary nature
based on evidence beyond that described in the announcement of Burke et al.
(2008), namely, the lack of significant correlation between spectral bisector
variations and orbital phase. In addition, using extensive spectroscopic
measurements spanning multiple seasons, we investigate the relatively large
scatter in the spectral line bisectors. We also examine possible blended
stellar configurations (hierarchical triples, chance alignments) that can mimic
the planet signals, and we are able to show that none are consistent with the
sum of all the data. The analysis of the S activity index shows no significant
stellar activity. Our results for the planet parameters are consistent with
values in Burke et al. (2008), and we refine both the stellar and planetary
parameters using our data. XO-5b orbits a slightly evolved, late G type star
with mass M_s = 0.88 +/- 0.03, radius R_s = 1.08 +/- 0.04, and metallicity
close to solar. The planetary mass and radius are M_p = 1.059 +/- 0.028 M_Jup
and R_p = 1.109 +/- 0.050 R_Jup, respectively, corresponding to a mean density
of 0.96 -0.11 +0.14 g/cm^3. The ephemeris for the orbit is P = 4.187757 +/-
0.000011, E= 2454552.67168 +/- 0.00029 (BJD) with transit duration of 0.1307
+/- 0.0013 d. By measuring four individual transit centers, we found no signs
for transit timing variations. The planet XO-5b is notable for its anomalously
high Safronov number, and has a high surface gravity when compared to other
transiting exoplanets with similar period.


title: The asymptotic behavior of least pseudo-Anosov dilatations

abstract:
  For a surface $S$ with $n$ marked points and fixed genus $g\geq2$, we prove
that the logarithm of the minimal dilatation of a pseudo-Anosov homeomorphism
of $S$ is on the order of $(\log n)/n$. This is in contrast with the cases of
genus zero or one where the order is $1/n$.


title: Effects of substrate relaxation on adsorption in pores

abstract:
  Fluids in porous media are commonly studied with analytical or simulation
methods, usually assuming that the host medium is rigid. By evaluating the
substrate's response (relaxation) to the presence of the fluid we assess the
error inherent in that assumption. One application is a determination of the
ground state of 3He in slit and cylindrical pores. With the relaxation, there
results a much stronger cohesion than would be found for a rigid host. Similar
increased binding effects of relaxation are found for classical fluids confined
within slit pores or nanotube bundles.


title: Invisibility and Inverse Problems

abstract:
  This survey of recent developments in cloaking and transformation optics is
an expanded version of the lecture by Gunther Uhlmann at the 2008 Annual
Meeting of the American Mathematical Society.


title: A Fast Generic Sequence Matching Algorithm

abstract:
  A string matching -- and more generally, sequence matching -- algorithm is
presented that has a linear worst-case computing time bound, a low worst-case
bound on the number of comparisons (2n), and sublinear average-case behavior
that is better than that of the fastest versions of the Boyer-Moore algorithm.
The algorithm retains its efficiency advantages in a wide variety of sequence
matching problems of practical interest, including traditional string matching;
large-alphabet problems (as in Unicode strings); and small-alphabet,
long-pattern problems (as in DNA searches). Since it is expressed as a generic
algorithm for searching in sequences over an arbitrary type T, it is well
suited for use in generic software libraries such as the C++ Standard Template
Library. The algorithm was obtained by adding to the Knuth-Morris-Pratt
algorithm one of the pattern-shifting techniques from the Boyer-Moore
algorithm, with provision for use of hashing in this technique. In situations
in which a hash function or random access to the sequences is not available,
the algorithm falls back to an optimized version of the Knuth-Morris-Pratt
algorithm.


title: QCD Cosmology from the Lattice Equation of State

abstract:
  We numerically determine the time dependence of the scale factor from the
lattice QCD equation of state, which can be used to define a QCD driven
cosmology. We compare a lattice approach to QCD cosmology at late times with
other models of the low temperature equation of state including the hadronic
resonance gas model, Hagedorn model and AdS/CFT.


title:
The ACS Nearby Galaxy Survey Treasury II. Young Stars and their Relation
  to Halpha and UV Emission Timescales in the M81 Outer Disk

abstract:
  We have obtained resolved stellar photometry from Hubble Space Telescope
(HST) Advanced Camera for Surveys (ACS) observations of a field in the outer
disk of M81 as part of the ACS Nearby Galaxy Survey Treasury (ANGST). Motivated
by the recent discovery of extended UV (XUV) disks around many nearby spiral
galaxies, we use the observed stellar population to derive the recent star
formation histories of five ~0.5 kpc-sized regions within this field. These
regions were selected on the basis of their UV luminosity from GALEX and
include two HII regions, two regions which are UV-bright but Halpha-faint, and
one "control" region faint in both UV and Halpha. We estimate our effective SFR
detection limit at ~2 x 10^-4 Msun/yr, which is lower than that of GALEX for
regions of this size. As expected, the HII regions contain massive main
sequence stars (in the mass range 18-27 Msun, based on our best extinction
estimates), while similar massive main sequence stars are lacking in the
UV-bright/Halpha-faint regions. The observations are consistent with stellar
ages <10 Myr in the HII regions, and >16 Myr in the UV-bright/Halpha-faint
regions. All regions but the control have formed ~10^4 Msun of stars over the
past ~65 Myr. Thus, our results, for at least one small area in the outer disk
of M81, are consistent with an age difference being sufficient to explain the
observed discrepancy between star-forming regions detected in Halpha and those
detected exclusively in UV. However, our data cannot conclusively rule out
other explanations, such as a strongly truncated initial mass function (IMF).


title: Long lived central engines in Gamma Ray Bursts

abstract:
  The central engine of Gamma Ray Bursts may live much longer than the duration
of the prompt emission. Some evidence of it comes from the presence of strong
precursors, post-cursors, and X-ray flares in a sizable fraction of bursts.
Additional evidence comes from the fact that often the X-ray and the optical
afterglow light curves do not track one another, suggesting that they are two
different emission components. The typical "steep-flat-steep" behavior of the
X-ray light curve can be explained if the same central engine responsible for
the main prompt emission continues to be active for a long time, but with a
decreasing power. The early X-ray "afterglow" emission is then the extension of
the prompt emission, originating at approximately the same location, and is not
due to forward shocks. If the bulk Lorentz factor Gamma is decreasing in time,
the break ending the shallow phase can be explained, since at early times Gamma
is large, and we see only a fraction of the emitting area. Later, when Gamma
decreases, we see an increasing fraction of the emitting surface up to the time
when Gamma ~ 1/theta_j. This time ends the shallow phase of the X-ray light
curve. The origin of the late prompt emission can be the accretion of the
fall-back material, with an accretion rate dot M proportional to t^(-5/3). The
combination of this late prompt emission with the flux produced by the standard
forward shock can explain the great diversity of the optical and the X-ray
light curves.


title: High Redshift Galaxies in the Hubble Ultra Deep Field

abstract:
  My dissertation presents results from three recent investigations in the
Hubble Ultra Deep Field (HUDF) focusing on understanding structural and
physical properties of high redshift galaxies. Here I summarize results from
these studies. This thesis work was conducted at Arizona State University under
the guidance of Prof. Rogier Windhorst and Prof. Sangeeta Malhotra.


title: An Introduction to Cascading Gravity and Degravitation

abstract:
  Cascading gravity is an explicit realization of the idea of degravitation,
where gravity behaves as a high-pass filter. This could explain why a large
cosmological constant does not backreact as much as anticipated from standard
General Relativity. The model relies on the presence of at least two infinite
extra dimensions while our world is confined on a four-dimensional brane.
Gravity is then four-dimensional at short distances and becomes weaker and
weaker at larger distances.


title: Non-canonical generalizations of slow-roll inflation models

abstract:
  We consider non-canonical generalizations of two classes of simple
single-field inflation models. First, we study the non-canonical version of
"ultra-slow roll" inflation, which is a class of inflation models for which
quantum modes do not freeze at horizon crossing, but instead evolve rapidly on
superhorizon scales. Second, we consider the non-canonical generalization of
the simplest "chaotic" inflation scenario, with a potential dominated by a
quartic (mass) term for the inflaton. We find a class of related non-canonical
solutions with polynomial potentials, but with varying speed of sound. These
solutions are characterized by a constant field velocity, and we dub such
models {\it isokinetic} inflation. As in the canonical limit, isokinetic
inflation has a slightly red-tilted power spectrum, consistent with current
data. Unlike the canonical case, however, these models can have an arbitrarily
small tensor/scalar ratio. Of particular interest is that isokinetic inflation
is marked by a correlation between the tensor/scalar ratio and the amplitude of
non-Gaussianity such that parameter regimes with small tensor/scalar ratio have
{\it large} associated non-Gaussianity, which is a distinct observational
signature.


title: The large-scale shock in the cluster of galaxies Hydra A

abstract:
  We analyzed a deep XMM-Newton observation of the cluster of galaxies Hydra A,
focusing on the large-scale shock discovered as a surface brightness
discontinuity in Chandra images. The shock front can be seen both in the
pressure map and in temperature profiles in several sectors. The Mach numbers
determined from the temperature jumps are in good agreement with the Mach
numbers derived from EPIC/pn surface brightness profiles and previously from
Chandra data and are consistent with M~1.3. The estimated shock age in the
different sectors using a spherically symmetric point explosion model ranges
between 130 and 230 Myr and the outburst energy between 1.5 and 3e61 ergs. The
shape of the shock seen in the pressure map can be approximated with an ellipse
centered 70 kpc towards the NE from the cluster center. We aimed to develop a
better model that can explain the offset between the shock center and the AGN
and give a consistent result on the shock age and energy. To this end, we
performed 3D hydrodynamical simulations in which the shock is produced by a
symmetrical pair of AGN jets launched in a spherical galaxy cluster. As an
explanation of the observed offset of the shock center, we consider large-scale
bulk flows in the intracluster medium. The simulation successfully reproduces
the size, ellipticity, and average Mach number of the observed shock front. The
predicted age of the shock is 160 Myr and the total input energy 3e61 erg. Both
values are within the range determined by the spherically symmetric model.
Matching the observed 70 kpc offset of the shock ellipse from the cluster
center requires large-scale coherent motions with a high velocity of 670 km/s.
We discuss the feasibility of this scenario and offer alternative ways to
produce the offset and to further improve the simulation.


title:
Images IV: Strong evolution of the oxygen abundance in gaseous phases of
  intermediate mass galaxies since z=0.8

abstract:
  Intermediate mass galaxies (logM(Msun)>10) at z~0.6 are the likeliest
progenitors of the present-day numerous population of spirals. There is growing
evidence that they have evolved rapidly since the last 6 to 8 Gyr ago, and
likely have formed a significant fraction of their stellar mass, often showing
perturbed morphologies and kinematics. We have gathered a representative sample
of 88 such galaxies and have provided robust estimates of their gas phase
metallicity. For doing so, we have used moderate spectral resolution
spectroscopy at VLT/FORS2 with unprecedented high S/N allowing to remove biases
coming from interstellar absorption lines and extinction to establish robust
values of R23=([OII]3727 + [OIII]4959,5007)/Hbeta. We definitively confirm that
the predominant population of z~0.6 starbursts and luminous IR galaxies (LIRGs)
are on average, two times less metal rich than the local galaxies at a given
stellar mass. We do find that the metal abundance of the gaseous phase of
galaxies is evolving linearly with time, from z=1 to z=0 and after comparing
with other studies, from z=3 to z=0. Combining our results with the reported
evolution of the Tully Fisher relation, we do find that such an evolution
requires that ~30% of the stellar mass of local galaxies have been formed
through an external supply of gas, thus excluding the close box model. Distant
starbursts & LIRGs have properties (metal abundance, star formation efficiency
& morphologies) similar to those of local LIRGs. Their underlying physics is
likely dominated by gas infall probably through merging or interactions. Our
study further supports the rapid evolution of z~0.4-1 galaxies. Gas exchanges
between galaxies is likely the main cause of this evolution.


title: Halo stochasticity in global clustering analysis

abstract:
  In the present work we study the statistics of haloes, which in the halo
model determines the distribution of galaxies. Haloes are known to be biased
tracer of dark matter, and at large scales it is usually assumed there is no
intrinsic stochasticity between the two fields. Following the work of Seljak &
Warren (2004), we explore how correct this assumption is and, moving a step
further, we try to qualify the nature of stochasticity. We use Principal
Component Analysis applied to the outputs of a cosmological N-body simulation
to: (1) explore the behaviour of stochasticity in the correlation between
haloes of different masses; (2) explore the behaviour of stochasticity in the
correlation between haloes and dark matter. We show results obtained using a
catalogue with 2.1 million haloes, from a PMFAST simulation with box size of
1000h^{-1}Mpc. In the relation between different populations of haloes we find
that stochasticity is not-negligible even at large scales. In agreement with
the conclusions of Tegmark & Bromley (1999) who studied the correlations of
different galaxy populations, we found that the shot-noise subtracted
stochasticity is qualitatively different from `enhanced' shot noise and,
specifically, it is dominated by a single stochastic eigenvalue. We call this
the `minimally stochastic' scenario, as opposed to shot noise which is
`maximally stochastic'. In the correlation between haloes and dark matter, we
find that stochasticity is minimized, as expected, near the dark matter peak (k
~ 0.02 h Mpc^{-1} for a LambdaCDM cosmology) and, even at large scales, it is
of the order of 15 per cent above the shot noise. Moreover, we find that the
reconstruction of the dark matter distribution is improved when we use
eigenvectors as tracers of the bias. [Abridged]


title:
New Measurement of the Relative Scintillation Efficiency of Xenon
  Nuclear Recoils Below 10 keV

abstract:
  Liquid xenon is an important detection medium in direct dark matter
experiments, which search for low-energy nuclear recoils produced by the
elastic scattering of WIMPs with quarks. The two existing measurements of the
relative scintillation efficiency of nuclear recoils below 20 keV lead to
inconsistent extrapolations at lower energies. This results in a different
energy scale and thus sensitivity reach of liquid xenon dark matter detectors.
We report a new measurement of the relative scintillation efficiency below 10
keV performed with a liquid xenon scintillation detector, optimized for maximum
light collection. Greater than 95% of the interior surface of this detector was
instrumented with photomultiplier tubes, giving a scintillation yield of 19.6
photoelectrons/keV electron equivalent for 122 keV gamma rays. We find that the
relative scintillation efficiency for nuclear recoils of 5 keV is 0.14, staying
constant around this value up to 10 keV. For higher energy recoils we measure a
value around 20%, consistent with previously reported data. In light of this
new measurement, the XENON10 experiment's results on spin-independent
WIMP-nucleon cross section, which were calculated assuming a constant 0.19
relative scintillation efficiency, change from $8.8\times10^{-44}$ cm$^2$ to
$9.9\times10^{-44}$ cm$^2$ for WIMPs of mass 100 GeV/c$^2$, and from
$4.4\times10^{-44}$ cm$^2$ to $5.6\times10^{-44}$ cm$^2$ for WIMPs of mass 30
GeV/c$^2$.


title: Hadronic Production of Gamma Rays and Starburst Galaxies

abstract:
  The Milky Way has been estabished to emit gamma rays. These gamma rays are
presumably dominated by decays of neutral pions, although inverse Compton
scatterings and bremsstrahlung also contribute. It is plausible that other
galaxies can be diffuse sources of gamma rays in a similar manner. Starburst
galaxies are particularly interesting to study as they are expected to have
much higher cosmic-ray fluxes and interstellar matter densities. The neutral
pions are created in cosmic-ray interactions with interstellar matter.
Presented here is an overview of the recent work by Karlsson and co-workers on
proton-proton interactions and the resulting secondary particle inclusive cross
sections and angular distributions. This model can be used to calculated the
$\pi^{0}$ component of the gamma-ray yield and spectrum from a starburst
galaxy. The yield is expected to increase significantly (30% to 50%) and the
spectrum to be harder than the incident proton spectrum.


title: Can non-private channels transmit quantum information?

abstract:
  We study the power of quantum channels with little or no capacity for private
communication. Because privacy is a necessary condition for quantum
communication, one might expect that such channels would be of little use for
transmitting quantum states. Nevertheless, we find strong evidence that there
are pairs of such channels that, when used together, can transmit far more
quantum information than the sum of their individual private capacities.
Because quantum transmissions are necessarily private, this would imply a large
violation of additivity for the private capacity. Specifically, we present
channels which display either (1) A large joint quantum capacity but very small
individual private capacities or (2) a severe violation of additivity for the
Holevo information.


title:
Evolution of the Dark Matter Phase-Space Density Distributions of LCDM
  Halos

abstract:
  We study the evolution of phase-space density during the hierarchical
structure formation of LCDM halos. We compute both a spherically-averaged
surrogate for phase-space density (Q) and the coarse-grained distribution
function f(x,v) for dark matter particles that lie within~2 virial radii of
four Milky-Way-sized dark matter halos. The estimated f(x,v) spans over four
decades at any radius. Dark matter particles that end up within two virial
radii of a Milky-Way-sized DM halo at $z=0$ have an approximately Gaussian
distribution in log(f) at early redshifts, but the distribution becomes
increasingly skewed at lower redshifts. The value corresponding to the peak of
the Gaussian decreases as the evolution progresses and is well described by a
power-law in (1+z). The highest values of f are found at the centers of dark
matter halos and subhalos, where f can be an order of magnitude higher than in
the center of the main halo. The power-law Q(r) profile likely reflects the
distribution of entropy (K = sigma^2/rho^{2/3} \propto r^{1.2}), which dark
matter acquires as it is accreted onto a growing halo. The estimated f(x, v),
on the other hand, exhibits a more complicated behavior. Although the median
coarse-grained phase-space density profile F(r) can be approximated by a
power-law in the inner regions of halos and at larger radii the profile
flattens significantly. This is because phase-space density averaged on small
scales is sensitive to the high-f material associated with surviving subhalos,
as well as relatively unmixed material (probably in streams) resulting from
disrupted subhalos, which contribute a sizable fraction of matter at large
radii. (ABRIDGED)


title:
Optically induced orientational transitions in nematics with planar
  alignment

abstract:
  Theoretical study of dynamical phenomena induced by a linearly polarized
plane wave incident perpendicularly on a planar aligned nematic layer with the
light intensity as the control parameter is reported. We find the threshold of
the Optically Induced Freedericksz Transition for the planar state as a
function of the problem parameters. It occurs that the threshold is
substantially lower than that expected before. Above the primary instability
the director settles either to a stationary or to an oscillatory states
depending on a thickness of the layer. These states become unstable at a
secondary threshold through a heteroclinic bifurcation and the director settles
to a new stationary distorted state.


title: A Fermi Sea of Heavy Electrons (a Kondo Lattice) is Never a Fermi Liquid

abstract:
  I demonstrate a contradiction which arises if we assume that the Fermi
surface in a heavy electron metal represents a finite jump in occupancy.


title: Random matrices with external source and KP $\tau$ functions

abstract:
  In this paper we prove that the partition function in the random matrix model
with external source is a KP $\tau$ function.