title: Model Checking Games for the Quantitative mu-Calculus

abstract:
  We investigate quantitative extensions of modal logic and the modal
mu-calculus, and study the question whether the tight connection between logic
and games can be lifted from the qualitative logics to their quantitative
counterparts. It turns out that, if the quantitative mu-calculus is defined in
an appropriate way respecting the duality properties between the logical
operators, then its model checking problem can indeed be characterised by a
quantitative variant of parity games. However, these quantitative games have
quite different properties than their classical counterparts, in particular
they are, in general, not positionally determined. The correspondence between
the logic and the games goes both ways: the value of a formula on a
quantitative transition system coincides with the value of the associated
quantitative game, and conversely, the values of quantitative parity games are
definable in the quantitative mu-calculus.


title:
Prospects for a direct dark matter search using high resistivity CCD
  detectors

abstract:
  The possibility of using CCD detectors in a low threshold direct detection
dark matter search experiment is discussed. We present the main features of the
DECam detectors that make them a good alternative for such an experiment,
namely their low noise and their large depleted volume. The performance of the
DECam CCDs for the detection of nuclear recoils is discussed, and a measurement
of the ionization efficiency for these events is presented. Finally the plans
and expected reach for the CCD Experiment at Low Background (CELB) are
discussed.


title:
Environmentally induced corrections to the geometric phase in a
  two-level system

abstract:
  We calculate the geometric phase for different open systems (spin-boson and
spin-spin models). We study not only how they are corrected by the presence of
the different type of environments but also discuss the appearence of
decoherence effects. These should be taken into account when planning
experimental setups to study the geometric phase in the nonunitary regime. We
propose a model with slow decoherence rate in which the geometric phase is
still modified and might be measured.


title: Floer homology and splicing knot complements

abstract:
  We obtain a formula for the Heegaard Floer homology (hat theory) of the
three-manifold $Y(K_1,K_2)$ obtained by splicing the complements of the knots
$K_i\subset Y_i$, $i=1,2$, in terms of the knot Floer homology of $K_1$ and
$K_2$. We also present a few applications. If $h_n^i$ denotes the rank of the
Heegaard Floer group $\widehat{\mathrm{HFK}}$ for the knot obtained by
$n$-surgery over $K_i$ we show that the rank of
$\widehat{\mathrm{HF}}(Y(K_1,K_2))$ is bounded below by
$$\big|(h_\infty^1-h_1^1)(h_\infty^2-h_1^2)- (h_0^1-h_1^1)(h_0^2-h_1^2)\big|.$$
We also show that if splicing the complement of a knot $K\subset Y$ with the
trefoil complements gives a homology sphere $L$-space then $K$ is trivial and
$Y$ is a homology sphere $L$-space.


title: Topologically massive gravity and complex Chern-Simons terms

abstract:
  This paper is withdrawn because its results have been previously reported in
arxiv hep-th/0507200.


title:
Spin squeezing of atomic ensembles via nuclear-electronic spin
  entanglement

abstract:
  Entangled many body systems have recently attracted significant attention in
various contexts. Among them, spin squeezed atoms and ions have raised interest
in the field of precision measurements, as they allow to overcome quantum noise
of uncorrelated particles. Precise quantum state engineering is also required
as a resource for quantum computation, and spin squeezing can be used to create
multi-partite entangled states. Two-mode spin squeezed systems have been used
for elementary quantum communication protocols. Until now spin squeezing has
been always achieved via generation of entanglement between different atoms of
the ensemble. In this Letter, we demonstrate for the first time ensemble spin
squeezing generated by engineering the quantum state of each individual atom.
More specifically, we entangle the nuclear and electronic spins of $10^{12}$
Cesium atoms at room temperature. We verify entanglement and ensemble spin
squeezing by performing quantum tomography on the atomic state.


title: Magnetic field induced ferroelectric loop in Bi0.75Sr0.25FeO3

abstract:
  Magnetic field induced ferroelectric hysteresis loop observed in
Bi0.75Sr0.25FeO3-delta is of prime importance. The coexistence of
antiferromagnetism and weak ferromagnetism is responsible for the original
magnetoelastic and magnetoferroelectric properties. Upon external magnetic
field application, the existence of a magnetostrictive effect supports a
structural transition towards a homogeneous antiferromagnetic and ferroelectric
phase. The magnetic field induced polarization is among the highest reported
for BiFeO3 based systems in either thin film or bulk forms (Pr=96 microC/cm2 at
10T) while the ferroelectric coercive field is among the lowest reported
(Hc=661(V/cm) at 10T). These properties make this material very attractive for
technical applications.


title: Delbr\"uck scattering in combined Coulomb and laser fields

abstract:
  We study Delbr\"uck scattering in a Coulomb field in the presence of a laser
field. The amplitudes are calculated in the Born approximation with respect to
the Coulomb field and exactly in the parameters of the laser field having
arbitrary strength, spectral content and polarization. The case of high energy
initial photon energy is investigated in detail for a monochromatic circularly
polarized laser field. It is shown that the angular distribution of the process
substantially differs from that for Delbr\"uck scattering in a pure Coulomb
field. The value of the cross section under discussion may exceed the latter at
realistic laser parameters that essentially simplify the possibility of the
experimental observation of the phenomenon. The effect of high order terms in
the quantum intensity parameter $\chi$ of the laser field is found to be very
important already at relatively small $\chi$.


title:
On measuring the masses of pair-produced semi-invisibly decaying
  particles at hadron colliders

abstract:
  A straightforward new technique is introduced which enables measurement at
hadron colliders of an analytical combination of the masses of pair-produced
semi-invisibly decaying particles and their invisible decay products. The new
technique makes use of the invariance under contra-linear Lorentz boosts of a
simple combination of the transverse momentum components of the aggregate
visible products of each decay chain. In the general case where the invariant
masses of the visible decay products are non-zero it is shown that in principle
the masses of both the initial particles from the hard scattering and the
invisible particles produced in the decay chains can be determined
independently. This application is likely to be difficult to realise in
practice however due to the contamination of the final state with ISR jets. The
technique may be of most use for measurements of SUSY particle masses at the
LHC, however the technique should be applicable to any class of hadron collider
events in which heavy particles of unknown mass are pair-produced and decay to
semi-invisible final states.


title: BHP universality and gaussianity in sunspot numbers fluctuations

abstract:
  We analyze the famous Wolf's sunspot numbers. We discovered that the
distribution of the sunspot number fluctuations is a mixture of the BHP
distribution with the Gaussian distribution.


title: Electron Emission in Superfluid and Low-temperature Vapor Phase Helium

abstract:
  Tungsten filaments used as sources of electrons in a low temperature liquid
or gaseous helium environment have remarkable properties of operating at
thousands of degrees Kelvin in surroundings at temperatures of order 1 K. We
provide an explanation of this performance in terms of important changes in the
thermal transport mechanisms. The behavior can be cast as a first-order phase
transition.


title: Flavour Physics and CP Violation: Expecting the LHC

abstract:
  The starting point of these lectures is an introduction to the weak
interactions of quarks and the Standard-Model description of CP violation,
where the central role is played by the Cabibbo-Kobayashi-Maskawa matrix and
the corresponding unitarity triangles. Since the B-meson system governs the
stage of (quark) flavour physics and CP violation, it is our main focus: we
shall classify B-meson decays, introduce the theoretical tools to deal with
them, investigate the requirements for non-vanishing CP-violating asymmetries,
and discuss the main strategies to explore CP violation and the preferred
avenues for physics beyond the Standard Model to enter. This formalism allows
us then to discuss important benchmark modes, where we will also address the
question of how much space for new-physics effects in the B studies at the LHC
is left by the recent experimental results from the B factories and the
Tevatron.


title:
Small angle neutron scattering study of the step-like magnetic
  transformation in Pr0.70Ca0.30MnO3

abstract:
  Small angle neutron scattering (SANS) magnetic and electrical transport
measurements were performed to study a single crystal of Pr0.7Ca0.3MnO3, a
colossal magnetoresistive (CMR) material. While the magnetic field induced
transformation of this phase separated compound consisting of an
antiferromagnetic insulating phase (AFI) and a ferromagnetic insulating phase
(FI), is continuous at high temperature (above 5K), at lower temperature a step
like transformation is observed (around 5T at 2K). Macroscopic magnetization
measurements and SANS indicate that this transformation occurs by the formation
of mesoscopic ferromagnetic metallic (FM) domains in the AFI phase, and,
eventually, in the FI phase. Although above 5K this transformation is
continuous, below 5K a magnetization step marks the abrupt transition from a
large scale FI/AFI phase separation to a large scale phase separation between
AFI, FI and FM phases. Our results suggest that relaxation of elastic strains
inherent to the coexistence of these different phases plays a crucial role in
the mechanism of these transformations. The occurrence of magnetization steps
could result from an intrinsic behavior of the AFI phase at low temperature.


title:
An Extended Model for the Evolution of Prebiotic Homochirality: A
  Bottom-Up Approach to the Origin of Life

abstract:
  A generalized autocatalytic model for chiral polymerization is investigated
in detail. Apart from enantiomeric cross-inhibition, the model allows for the
autogenic (non-catalytic) formation of left and right-handed monomers from a
substrate with reaction rates $\epsilon_L$ and $\epsilon_R$, respectively. The
spatiotemporal evolution of the net chiral asymmetry is studied for models with
several values of the maximum polymer length, N. For N=2, we study the validity
of the adiabatic approximation often cited in the literature. We show that the
approximation obtains the correct equilibrium values of the net chirality, but
fails to reproduce the short time behavior. We show also that the autogenic
term in the full N=2 model behaves as a control parameter in a chiral symmetry-
breaking phase transition leading to full homochirality from racemic initial
conditions. We study the dynamics of the N -> infinity model with symmetric
($\epsilon_L = \epsilon_R$) autogenic formation, showing that it only achieves
homochirality for $\epsilon < \epsilon_c$, where $\epsilon_c$ is an N-dependent
critical value. For $\epsilon \leq \epsilon_c$ we investigate the behavior of
models with several values of N, showing that the net chiral asymmetry grows as
tanh(N). We show that for a given symmetric autogenic reaction rate, the net
chirality and the concentrations of chirally pure polymers increase with the
maximum polymer length in the model. We briefly discuss the consequences of our
results for the development of homochirality in prebiotic Earth and possible
experimental verification of our findings.


title: Unital ${A}_\infty$-categories

abstract:
  We prove that three definitions of unitality for A-infinity-categories
suggested by the first author, by Kontsevich and Soibelman, and by Fukaya are
equivalent.


title: q-Abel polynomials

abstract:
  This note gives a simple approach to q-analogues of some results associated
with Abel polynomials.


title:
On Cartan Spaces with the $m$-th Root Metric
  $K(x,p)=\sqrt[m]{a^{i_{1}i_{2}...i_{m}}(x)p_{i_{1}}p_{i_{2}}...p_{i_{m}}}$

abstract:
  The aim of this paper is to expose some geometrical properties of the locally
Minkowski-Cartan space with the Berwald-Moor metric of momenta. This space is
regarded as a particular case of the $m$-th root Cartan space. Thus, Section 2
studies the $v$-covariant derivation components of the $m$-th root Cartan
space. Section 3 computes the $v$-curvature d-tensor $S^{hijk}$ of the m-th
root Cartan space and studies conditions for $S3$-likeness. Section 4 computes
the $T$-tensor $T^{hijk}$ of the m-th root Cartan space. Section 5
particularizes the preceding geometrical results for the Berwald-Moor metric of
momenta.


title: The entropy of network ensembles

abstract:
  In this paper we generalize the concept of random networks to describe
networks with non trivial features by a statistical mechanics approach. This
framework is able to describe ensembles of undirected, directed as well as
weighted networks. These networks might have not trivial community structure
or, in the case of networks embedded in a given space, non trivial distance
dependence of the link probability. These ensembles are characterized by their
entropy which evaluate the cardinality of networks in the ensemble. The general
framework we present in this paper is able to describe microcanonical ensemble
of networks as well as canonical or hidden variables network ensemble with
significant implication for the formulation of network constructing algorithms.
Moreover in the paper we define and and characterize in particular the
"structural entropy", i.e. the entropy of the ensembles of undirected
uncorrelated simple networks with given degree sequence. We discuss the
apparent paradox that scale-free degree distribution are characterized by
having small structural entropy but are so widely encountered in natural,
social and technological complex systems. We give the proof that while
scale-free networks ensembles have small structural entropy, they also
correspond to the most likely degree distribution with the corresponding value
of the structural entropy.


title: MOND: A consequence of the geometric Leibniz Clock

abstract:
  Leibniz considered the notion of the 'empty physical space' to be a
meaningless abstraction, and he held firmly to the view that the only
significant thing was the set of relationships between 'objects', whatever
these 'objects' might be. Similarly, he was equally clear in expressing his
views about Newton's universal time, which he also considered to be a
meaningless abstraction. In effect, for him, time was no more than a synonym
for ordered change within a material system.
  The process of giving quantitative realization to this duality of
non-Newtonian ideas forms the core of this work. A primary result arising is
that every gravitating particle is no more than a clock - the geometric Leibniz
Clock - which provides all the basic things: it conserves energy and angular
momentum and satisfies the Weak Equivalence Principle.
  When the Clock is applied to model the concept of a galactic object within
which all motions are circular, the characteristic properties of the MOND
galaxy (asymptotic flatness, a critical acceleration scale, the baryonic
Tully-Fisher relationship) are quantitatively reproduced in the resulting
Leibniz galaxy. In short, the characteristic essence of MOND has its source in
the geometric Leibniz Clock.


title: BPS preons and the AdS-M-algebra

abstract:
  We present here the AdS generalization of BPS preons, which were introduced
as the hypothetical constituents of M-theory preserving all but one
supersymmetries. Our construction, suggested by the relation of `lower
dimensional preons' with higher spin theories, can be considered as a
deformation of the M-algebraic description of the single supersymmetry broken
by a preon, and provides another reason to identify the AdS generalization of
the M-algebra, which we call the AdS-M-algebra, with osp(1|32).


title: Systematic study of pentaquark states: $qqq-q\bar{q}$ configuration

abstract:
  Group theoretic method for the systematic study of five-quark states with
meson-baryon ($q\bar{q}-q^3$) configuration is developed. The calculation of
matrix elements of many body Hamiltonian is simplified by transforming the
physical bases (meson-baryon quark cluster bases) to symmetry bases (group
chain classified bases), where the fractional parentage expansion method can be
used. Three quark models, the naive Glashow-Isgur model, Salamanca chiral quark
model and quark delocalization color screening model, are used to show the
general applicability of the method and general results of constituent quark
models for five-quark states are given. The method can also be useful in the
calculation of meson-baryon scattering and the study of the five-quark
components effect in baryon structure. The physical contents of different model
configurations for the same multi-quark system can also be compared through the
transformation between different physical bases to the same set of symmetry
bases.


title: Anisotropic spin relaxation in graphene

abstract:
  Spin relaxation in graphene is investigated in electrical graphene spin valve
devices in the non-local geometry. Ferromagnetic electrodes with in-plane
magnetizations inject spins parallel to the graphene layer. They are subject to
Hanle spin precession under a magnetic field $B$ applied perpendicular to the
graphene layer. Fields above 1.5 T force the magnetization direction of the
ferromagnetic contacts to align to the field, allowing injection of spins
perpendicular to the graphene plane. A comparison of the spin signals at B = 0
and B = 2 T shows a 20 % decrease in spin relaxation time for spins
perpendicular to the graphene layer compared to spins parallel to the layer. We
analyze the results in terms of the different strengths of the spin orbit
effective fields in the in-plane and out-of-plane directions.


title: Experimental evidence of antiproton reflection by a solid surface

abstract:
  We report here experimental evidence of the reflection of a large fraction of
a beam of low energy antiprotons by an aluminum wall. This derives from the
analysis of a set of annihilations of antiprotons that come to rest in rarefied
helium gas after hitting the end wall of the apparatus. A Monte Carlo
simulation of the antiproton path in aluminum indicates that the observed
reflection occurs primarily via a multiple Rutherford-style scattering on Al
nuclei, at least in the energy range 1-10 keV where the phenomenon is most
visible in the analyzed data. These results contradict the common belief
according to which the interactions between matter and antimatter are dominated
by the reciprocally destructive phenomenon of annihilation.


title:
Invariance de la Gamma-dimension pour certaines familles
  k\"ahl\'eriennes de dimension 3

abstract:
  In this article, we study some properties of deformation invariance of the
Gamma-dimension (defined for X a compact k\"ahler manifold). This birational
invariant is defined as the codimension of the maximal compact subvarieties in
the universal cover of X. In the surface case, the deformation invariance is a
straightforward consequence of a theorem of Y.-T. Siu. Using some results from
F. Campana et Q. Zhang, we settle this invariance for certain type of K\"ahler
families of dimension 3.


title: The Ionizing Stars of the Galactic Ultra-Compact HII Region G45.45+0.06

abstract:
  Using the NIFS near-infrared integral-field spectrograph behind the facility
adaptive optics module, ALTAIR, on Gemini North, we have identified several
massive O-type stars that are responsible for the ionization of the Galactic
Ultra-Compact HII region G45.45+0.06. The sources ``m'' and ``n'' from the
imaging study of Feldt et a. 1998 are classified as hot, massive O-type stars
based on their K-band spectra. Other bright point sources show red and/or
nebular spectra and one appears to have cool star features that we suggest are
due to a young, low-mass pre-main sequence component. Still two other embedded
sources (``k'' and ``o'' from Feldt et al.) exhibit CO bandhead emission that
may arise in circumstellar disks which are possibly still accreting. Finally,
nebular lines previously identified only in higher excitation planetary nebulae
and associated with KrIII and SeIV ions are detected in G45.45+0.06.


title:
Spontaneous R-parity violation: Lightest neutralino decays and neutrino
  mixing angles at future colliders

abstract:
  We study the decays of the lightest supersymmetric particle (LSP) in models
with spontaneously broken R-parity. We focus on the two cases that the LSP is
either a bino or a neutral singlet lepton. We work out the most important
phenomenological differences between these two scenarios and discuss also how
they might be distinguished from explicit R-Parity breaking models. In both
cases we find that certain ratios of decay branching ratios are correlated with
either the solar or the atmospheric (and reactor) neutrino angle. The
hypothesis that spontaneous R-Parity violation is the source of the observed
neutrino masses is therefore potentially testable at the LHC.


title: The inverse problem of differential Galois theory over the field R(z)

abstract:
  We describe a Picard-Vessiot theory for differential fields with non
algebraically closed fields of constants. As a technique for constructing and
classifying Picard-Vessiot extensions, we develop a Galois descent theory. We
utilize this theory to prove that every linear algebraic group $G$ over
$\mathbb{R}$ occurs as a differential Galois group over $\mathbb{R}(z)$. The
main ingredient of the proof is the Riemann-Hilbert correspondence for regular
singular differential equations over $\mathbb{C}(z)$.


title:
Lyapunov Functionals and Local Dissipativity for the Vorticity Equation
  in L^p and Besov Spaces

abstract:
  In this paper we establish the local Lyapunov property of certain L^p and
Besov norms of the vorticity fields. We have resolved in part, a certain open
problem posed by Tosio Kato for the three dimensional Navier Stokes equation by
studying the vorticity equation. The local dissipativity of the sum of linear
and non-linear operators of the vorticity equation is established. One of the
main techniques used here is Littlewood-Paley analysis.


title:
Optimal design of nanoplasmonic materials using genetic algorithms as a
  multi-parameter optimization tool

abstract:
  An optimal control approach based on multiple parameter genetic algorithms is
applied to the design of plasmonic nanoconstructs with pre-determined optical
properties and functionalities. We first develop nanoscale metallic lenses that
focus an incident plane wave onto a pre-specified, spatially confined spot. Our
results illustrate the role of symmetry breaking and unravel the principles
that favor dimeric constructs for optimal light localization. Next we design a
periodic array of silver particles to modify the polarization of an incident,
linearly-polarized plane wave in a desired fashion while localizing the light
in space. The results provide insight into the structural features that
determine the birefringence properties of metal nanoparticles and their arrays.
Of the variety of potential applications that may be envisioned, we note the
design of nanoscale light sources with controllable coherence and polarization
properties that could serve for coherent control of molecular or electronic
dynamics in the nanoscale.


title:
Quantitative piezoelectric force microscopy: Influence of tip shape,
  size, and contact geometry on the nanoscale resolution of an antiparallel
  ferroelectric domain wall

abstract:
  The structure of a single antiparallel ferroelectric domain wall in LiNbO3 is
quantitatively mapped by piezoelectric force microscopy (PFM) with calibrated
probe geometry. The PFM measurements are performed for 49 probes with the
radius varying from 10 to 300 nm. The magnitude and variation of the
experimental piezoelectric coefficient across a domain wall matches the
profiles calculated from a comprehensive analytical theory, as well as
3-dimensional finite element method simulations. Quantitative agreement between
experimental and theoretical profile widths is obtained only when a finite
disk-type tip radius that is in true contact with the sample surface is
considered, which is in agreement with scanning electron microscopy images of
the actual tips after imaging. The magnitude of the piezoelectric coefficient
is shown to be independent of the tip radius, and the PFM profile width is
linearly proportional to the tip radius. Finally we demonstrate a method to
extract any intrinsic material broadening of the ferroelectric wall width.
Surprisingly wide wall widths of 20- 200nm are observed.


title: Stochastic 2-D Navier-Stokes Equation with Artificial Compressibility

abstract:
  In this paper we study the stochastic Navier-Stokes equation with artificial
compressibility. The main results of this work are the existence and uniqueness
theorem for strong solutions and the limit to incompressible flow. These
results are obtained by utilizing a local monotonicity property of the sum of
the Stokes operator and the nonlinearity.


title: Reflection of OH molecules from magnetic mirrors

abstract:
  We have reflected a Stark-decelerated beam of OH molecules under normal
incidence from mirrors consisting of permanent magnets. Two different types of
magnetic mirrors have been demonstrated. A long-range flat mirror made from a
large disc magnet has been used to spatially focus the reflected beam in the
longitudinal direction ("bunching"). A short-range curved mirror composed of an
array of small cube magnets allows for transverse focusing of the reflected
beam.


title: Stable Sheaves Over K3 Fibrations

abstract:
  We construct stable sheaves over K3 fibrations using a relative Fourier-Mukai
transform which describes the sheaves in terms of spectral data similar to the
construction for elliptic fibrations. On K3 fibered Calabi-Yau threefolds we
show that the Fourier-Mukai transform induces an embedding ion of the relative
Jacobian of spectral line bundles on spectral covers into the moduli space of
sheaves of given invariants. This makes the moduli space of spectral sheaves to
a generic torus fibration over the moduli space of curves of given arithmetic
genus on the Calabi-Yau manifold.


title:
Transverse momentum broadening of vector boson production in high energy
  nuclear collisions

abstract:
  We calculate in perturbative QCD the transverse momentum broadening of vector
boson production in high energy nuclear collisions. We evaluate the effect of
initial-state parton multiple scattering for the production of the Drell-Yan
virtual photon and $W/Z$ bosons. We calculate both the initial- and final-state
multiple scattering effect for the production of heavy quarkonia and their
transverse momentum broadening in both NRQCD and Color Evaporation model of
quarkonium formation. We find that J/$\psi$ and $\Upsilon$ broadening in
hadron-nucleus collision is close to $2C_A/C_F$ times the corresponding
Drell-Yan broadening, which gives a good description of existing Fermilab data.
Our calculations are also consistent with RHIC data on J/$\psi$ broadening in
relativistic heavy ion collisions. We predict the transverse momentum
broadening of vector boson (J/$\psi$, $\Upsilon$, and $W/Z$) production in
relativistic heavy ion collisions at the LHC, and discuss the role of the
vector boson broadening in diagnosing medium properties.


title: On antipodal spherical t-designs of degree s with $t\geq 2s-3$

abstract:
  We prove that if X is a spherical t-design and s-distance set with $t\geq
2s-3$, then X has the structure of Q-polynomial association scheme of class s.
Also, we describe the parameters of the association scheme.


title: Classification Constrained Dimensionality Reduction

abstract:
  Dimensionality reduction is a topic of recent interest. In this paper, we
present the classification constrained dimensionality reduction (CCDR)
algorithm to account for label information. The algorithm can account for
multiple classes as well as the semi-supervised setting. We present an
out-of-sample expressions for both labeled and unlabeled data. For unlabeled
data, we introduce a method of embedding a new point as preprocessing to a
classifier. For labeled data, we introduce a method that improves the embedding
during the training phase using the out-of-sample extension. We investigate
classification performance using the CCDR algorithm on hyper-spectral satellite
imagery data. We demonstrate the performance gain for both local and global
classifiers and demonstrate a 10% improvement of the $k$-nearest neighbors
algorithm performance. We present a connection between intrinsic dimension
estimation and the optimal embedding dimension obtained using the CCDR
algorithm.


title: Time-resolved photoluminescence of n-doped SrTiO_3

abstract:
  Following the recent surge of interest in n-doped strontium titanate as a
possible blue light emitter, a time-resolved photoluminescence analysis was
performed on nominally pure, Nb-doped and oxygen-deficient single-crystal
SrTiO3 samples. The doping-effects on both the electronic states involved in
the transition and the decay mechanism are respectively analyzed by comparing
the spectral and dynamic features and the yields of the emission. Our
time-resolved analysis, besides shedding some light on the basic recombination
mechanisms acting in these materials, sets the intrinsic bandwidth limit of the
proposed blue light emitting optoelectronic devices made of Ti-based
perovskites heterostructures in the GHz range.


title: Topological Strings on Grassmannian Calabi-Yau manifolds

abstract:
  We present solutions for the higher genus topological string amplitudes on
Calabi-Yau-manifolds, which are realized as complete intersections in
Grassmannians. We solve the B-model by direct integration of the holomorphic
anomaly equations using a finite basis of modular invariant generators, the gap
condition at the conifold and other local boundary conditions for the
amplitudes. Regularity of the latter at certain points in the moduli space
suggests a CFT description. The A-model amplitudes are evaluated using a mirror
conjecture for Grassmannian Calabi-Yau by Batyrev, Ciocan-Fontanine, Kim and
Van Straten. The integrality of the BPS states gives strong evidence for the
conjecture.


title: Random Lie group actions on compact manifolds: A perturbative analysis

abstract:
  A random Lie group action on a compact manifold generates a discrete time
Markov process. The main object of this paper is the evaluation of associated
Birkhoff sums in a regime of weak, but sufficiently effective coupling of the
randomness. This effectiveness is expressed in terms of random Lie algebra
elements and replaces the transience or Furstenberg's irreducibility hypothesis
in related problems. The Birkhoff sum of any given smooth function then turns
out to be equal to its integral w.r.t. a unique smooth measure on the manifold
up to errors of the order of the coupling constant. Applications to the theory
of products of random matrices and a model of a disordered quantum wire are
presented.


title: Exact Isospectral Pairs of PT-Symmetric Hamiltonians

abstract:
  A technique for constructing an infinite tower of pairs of PT-symmetric
Hamiltonians, $\hat{H}_n$ and $\hat{K}_n$ (n=2,3,4,...), that have exactly the
same eigenvalues is described. The eigenvalue problem for the first Hamiltonian
$\hat{H}_n$ of the pair must be posed in the complex domain, so its
eigenfunctions satisfy a complex differential equation and fulfill homogeneous
boundary conditions in Stokes' wedges in the complex plane. The eigenfunctions
of the second Hamiltonian $\hat{K}_n$ of the pair obey a real differential
equation and satisfy boundary conditions on the real axis. This equivalence
constitutes a proof that the eigenvalues of both Hamiltonians are real.
Although the eigenvalue differential equation associated with $\hat{K}_n$ is
real, the Hamiltonian $\hat{K}_n$ exhibits quantum anomalies (terms
proportional to powers of $\hbar$). These anomalies are remnants of the complex
nature of the equivalent Hamiltonian $\hat{H}_n$. In the classical limit in
which the anomaly terms in $\hat{K}_n$ are discarded, the pair of Hamiltonians
$H_{n,classical}$ and $K_{n,classical}$ have closed classical orbits whose
periods are identical.


title:
Magnetization of a neutron plasma with Skyrme and Gogny forces in the
  presence of a strong magnetic field

abstract:
  Some thermodynamical magnitudes of interest in a pure neutron plasma are
studied within the framework of the non-relativistic Brueckner-Hartree-Fock
approximation at finite density and temperature. We use Skyrme and Gogny forces
to describe such a neutron plasma and study the main differences that arise in
these two effective parametrizations of the nuclear interaction when a strong
magnetic field induces a permanent magnetization in the gas. The existence of a
non-zero permanent spin polarization in a neutron plasma is explored in the
density-temperature parameter space. We find that for moderate temperatures and
in the low density range up to densities $\approx 0.5\rho_0$ both
parametrizations predict that as density decreases an increasingly strong
magnetization is allowed. In the range $0.5 \rho_0 \lesssim \rho \lesssim 3
\rho_0$ there is an approximately constant polarization that can be as big as
$\approx 12%$ for the maximum allowed interior magnetic field $B \approx
10^{18}$ G. For higher densities there is a dramatic difference in the
polarization trend followed by Skyrme an Gogny forces. While the former predict
a ferromagnetic phase transition, the Gogny forces prevent it keeping the
magnetization below 5%.


title:
Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D
  Detection Method and First Results

abstract:
  The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) grism
PEARS (Probing Evolution And Reionization Spectroscopically) survey provides a
large dataset of low-resolution spectra from thousands of galaxies in the GOODS
North and South fields. One important subset of objects in these data are
emission-line galaxies (ELGs), and we have investigated several different
methods aimed at systematically selecting these galaxies. Here we present a new
methodology and results of a search for these ELGs in the PEARS observations of
the Hubble Ultra Deep Field (HUDF) using a 2D detection method that utilizes
the observation that many emission lines originate from clumpy knots within
galaxies. This 2D line-finding method proves to be useful in detecting emission
lines from compact knots within galaxies that might not otherwise be detected
using more traditional 1D line-finding techniques. We find in total 96 emission
lines in the HUDF, originating from 81 distinct "knots'' within 63 individual
galaxies. We find in general that [OIII] emitters are the most common,
comprising 44% of the sample, and on average have high equivalent widths (70%
of [OIII] emitters having rest-frame EW>100A). There are 12 galaxies with
multiple emitting knots--with different knots exhibiting varying flux values,
suggesting that the differing star formation properties across a single galaxy
can in general be probed at redshifts z~0.2-0.4. The most prevalent
morphologies are large face-on spirals and clumpy interacting systems, many
being unique detections owing to the 2D method described here, thus
highlighting the strength of this technique.


title: Spectral averaging techniques for Jacobi matrices

abstract:
  Spectral averaging techniques for one-dimensional discrete Schroedinger
operators are revisited and extended. In particular, simultaneous averaging
over several parameters is discussed. Special focus is put on proving lower
bounds on the density of the averaged spectral measures. These Wegner type
estimates are used to analyze stability properties for the spectral types of
Jacobi matrices under local perturbations.


title:
Some Consequences of Gravitationally Induced Electromagnetic Effects in
  Microphysics

abstract:
  We discuss the relation between the gravitational and electromagnetic fields
as governed by the Einstein-Maxwell field equations. It is emphasized that the
tendency of the gravitational field to induce electromagnetic effects increases
as the size of the system goes down. In particular, the gravitational field,
according to general relativity, tends to become dominated by the spin at
distances of the order of the Compton wavelength. The relevant quantity which
governs this behavior is the ratio S/M^2 where S is the (spin) angular
momentum. For an electron, S/M^2 ~ 10^44. Therefore, gravitomagnetic effects
will play a significant role in the subatomic domain. To analyze this situation
we use the asymptotic structure in the form of the multipole fields. Some
important consequences for the electromagnetic fields of charged particles with
spin are pointed out. In particular, the gravitational field may induce
corrections to the Coulomb field which can be tested experimentally.


title:
Electric-field-induced spin-flop in BiFeO3 single crystals at
  room-temperature

abstract:
  Bismuth ferrite, BiFeO3, is the only known room-temperature 'multiferroic'
material. We demonstrate here, using neutron scattering measurements in high
quality single crystals, that the antiferromagnetic and ferroelectric orders
are intimately coupled. Initially in a single ferroelectric state, our crystals
have a canted antiferromagnetic structure describing a unique cycloid. Under
electrical poling, polarisation re-orientation induces a spin flop. We argue
here that the coupling between the two orders may be stronger in the bulk than
that observed in thin films where the cycloid is absent.


title: Inflation at the Tip

abstract:
  We study the motion of a (space filling) D3-brane at the tip of a warped
deformed conifold, looking for inflationary trajectories. In our setup no anti
D3-brane is present and the inflaton potential is induced by threshold
corrections to the superpotential. First we study the slow roll regime and find
that, allowing for fine tuning, hilltop inflation compatible with CMB data can
take place. Then we consider the DBI regime and formulate a necessary condition
for a phenomenologically viable inflationary stage. En passant, we propose a
mechanism to cancel the large inflaton mass in the standard radial D3-anti
D3-brane inflation.


title: Utility of a Special Second Scalar Doublet

abstract:
  This Brief Review deals with the recent resurgence of interest in adding a
second scalar doublet (eta^+,eta^0) to the Standard Model of particle
interactions. In most studies, it is taken for granted that eta^0 should have a
nonzero vacuum expectation value, even if it may be very small. What if there
is an exactly conserved symmetry which ensures <eta^0>=0? The phenomenological
ramifications of this idea include dark matter, radiative neutrino mass,
leptogenesis, and grand unification.


title: Constructions for infinitesimal group schemes

abstract:
  Let G be an infinitesimal group scheme over a field k of positive
characteristic p. We introduce the global p-nilpotent operator $\Theta_G: k[G]
\to k[V(G)]$, where V(G) is the scheme which represents 1-parameter subgroups
of G. This operator applied to M encodes the local Jordan type of M, and leads
to computational insights into the representation theory of G. For certain
G-modules (including those of constant Jordan type), we employ the global
p-nilpotent operator to associate various algebraic vector bundles on the
projective scheme $\bP(G)$, the projectivization of the scheme of one-parameter
subgroups of G. These vector bundles not only distinguish certain
representations with the same local Jordan type, but also provide a method of
constructing algebraic vector bundles on $\bP(G)$.


title:
Renormalization Group Determination of the Five-Loop Effective Potential
  for Massless Scalar Field Theory

abstract:
  The five-loop effective potential and the associated summation of subleading
logarithms for O(4) globally-symmetric massless $\lambda\phi^4$ field theory in
the Coleman-Weinberg renormalization scheme $\frac{d^4V}{d\phi^4}|_{\phi = \mu}
= \lambda$ (where $\mu$ is the renormalization scale) is calculated via
renormalization-group methods. An important aspect of this analysis is
conversion of the known five-loop renormalization-group functions in the
minimal-subtraction (MS) scheme to the Coleman-Weinberg scheme.


title:
On Normalized Table Algebras Generated by a Faithful Non-real Element of
  Degree 3-II

abstract:
  The concept of "table algebra" was introduced by Z Arad anf H. Blau in order
to study in a uniform way properties of products of conjugacy classes and of
irreducible characters of a finite group, Except for certain cases which remain
open, Normalized Table Algebras Generated by a Faithful Non- real Element of
degree 3. As application we classified finite groups with a faithful non-real
irreducible character of dimension 3 without using character theory of finite
groups.


title:
Rank one Eisenstein cohomology of local systems on the moduli space of
  abelian varieties

abstract:
  We give a formula for the Eisenstein cohomology of local systems on the
partial compactification of the moduli of principally polarized abelian
varieties given by rank 1 degenerations. For genus 2 we give a formula for the
full Eisenstein cohomology.


title: High Energy Positrons and the WMAP Haze from Exciting Dark Matter

abstract:
  We consider the signals of positrons and electrons from "exciting" dark
matter (XDM) annihilation. Because of the light (m_phi ~< 1 GeV) force carrier
phi into which the dark matter states can annihilate, the electrons and
positrons are generally very boosted, yielding a hard spectrum, in addition to
the low energy positrons needed for INTEGRAL observations of the galactic
center. We consider the relevance of this scenario for HEAT, PAMELA and the
WMAP "haze," focusing on light (m_phi ~< 2 m_pi) phi bosons, and find that
significant signals can be found for all three, although significant signals
generally require high dark matter densities. We find that measurements of the
positron fraction are generally insensitive to the halo model, but do suffer
significant astrophysical uncertainties. We discuss the implications for
upcoming PAMELA results.


title: Diagrammatic Monte Carlo

abstract:
  Diagrammatic Monte Carlo (DiagMC) is a numeric technique that allows one to
calculate quantities specified in terms of diagrammatic expansions, the latter
being a standard tool of many-body quantum statistics. The sign problem that is
typically fatal to Monte Carlo approaches, appears to be manageable with
DiagMC. Starting with a general introduction to the principles of DiagMC, we
present a detailed description of the DiagMC scheme for interacting fermions
(Hubbard model), as well as the first illustrative results for the equations of
state.


title: Duke's Theorem and Continued Fractions

abstract:
  For uniformly chosen random $\alpha \in [0,1]$, it is known the probability
the $n^{\rm th}$ digit of the continued-fraction expansion, $[\alpha]_n$
converges to the Gauss-Kuzmin distribution $\mathbb{P}([\alpha]_n = k) \approx
\log_2 (1 + 1/ k(k+2))$ as $n \to \infty$. In this paper, we show the continued
fraction digits of $\sqrt{d}$, which are eventually periodic, also converge to
the Gauss-Kuzmin distribution as $d \to \infty$ with bounded class number,
$h(d)$. The proof uses properties of the geodesic flow in the unit tangent
bundle of the modular surface, $T^1(\text{SL}_2 \mathbb{Z}\backslash
\mathbb{H})$.


title: An Advice about Shimming in High-Resolution Nuclear Magnetic Resonance

abstract:
  Three methods of active shimming in high-resolution NMR in existence (manual
shimming, lock optimization and gradient shimming) are briefly discussed and
their advantages and shortcomings are compared and also an advice on their use
is given.


title: Empirical oscillating potentials for alloys from ab-initio fits

abstract:
  By fitting to a database of ab-initio forces and energies, we can extract
pair potentials for alloys, with a simple six-parameter analytic form including
Friedel oscillations, which give a remarkably faithful account of many complex
intermetallic compounds. As examples we show results for (crystal or
quasicrystal) structure prediction and phonon spectrum for three systems:
Fe--B, Al--Mg--Zn, and Al--Cu--Fe.


title: High energy cosmic rays from AGN and the GZK cutoff

abstract:
  Based on a model for the emission of high energy cosmic rays from AGN (Active
Galactic Nuclei) that has been proposed by the author, he reviews the status of
the GZK cutoff and the correlation of high energy cosmic ray sources with AGN
locations in the existing data. The determination of mass for the incident
particles seems to be a key factor, and a suggestion for doing that has been
made in this article.


title: Essentialities in additive bases

abstract:
  Let A be an asymptotic basis for N_0 of some order. By an essentiality of A
one means a subset P such that A\P is no longer an asymptotic basis of any
order and such that P is minimal among all subsets of A with this property. A
finite essentiality of A is called an essential subset. In a recent paper,
Deschamps and Farhi asked the following two questions : (i) does every
asymptotic basis of N_0 possess some essentiality ? (ii) is the number of
essential subsets of size at most k of an asymptotic basis of order h bounded
by a function of k and h only (they showed the number is always finite) ? We
answer the latter question in the affirmative, and the former in the negative
by means of an explicit construction, for every integer h >= 2, of an
asymptotic basis of order h with no essentialities.


title:
Quantum initial condition sampling for linearized density matrix
  dynamics: Vibrational pure dephasing of iodine in krypton matrices

abstract:
  This paper reviews the linearized path integral approach for computing time
dependent properties of systems that can be approximated using a mixed
quantum-classical description. This approach is applied to studying vibrational
pure dephasing of ground state molecular iodine in a rare gas matrix. The
Feynman-Kleinert optimized harmonic approximation for the full system density
operator is used to sample initial conditions for the bath degrees of freedom.
This extremely efficient approach is compared with alternative initial
condition sampling techniques at low temperatures where classical initial
condition sampling yields dephasing rates that are nearly an order of magnitude
too slow compared with quantum initial condition sampling and experimental
results.


title:
The Great Observatories Origins Deep Survey. VLT/VIMOS Spectroscopy in
  the GOODS-South Field

abstract:
  We present the first results of the VIsible Multiobject Spectrograph (VIMOS)
ESO/GOODS program of spectroscopy of faint galaxies in the Chandra Deep Field
South (CDF-S). The program complements the FORS2 ESO/GOODS campaign. 3312
spectra have been obtained in service mode with VIMOS at the ESO/VLT UT3. The
VIMOS LR-Blue and MR grisms have been used to cover different redshift ranges.
Galaxies at 1.8 < z < 3.5 have been observed in the GOODS VIMOS-LR-Blue
campaign. Galaxies at z < 1 and Lyman Break Galaxies at z > 3.5 have been
observed in the VIMOS MR survey. Here we report results for the first 6 masks
(out of 10 total) that have been analyzed from each of the LR-Blue and MR
grisms. Spectra of 2344 spectra have been extracted from these 6 LR-Blue masks
and 968 from 6 MR masks. 33% of the LR-Blue and 18% of the MR spectra are
serendipitous observations. We obtained 1481 redshifts in the LR-Blue campaign
and 656 in the MR campaign for a total success rate of 63% and 68%,
respectively, which increase to 70% and 75% when only the primary targets are
considered. By complementing our VIMOS spectroscopic catalog with all existing
spectroscopic redshifts publicly available in the CDF-S, we created a redshift
master catalog. By comparing this redshift compilation with different
photometric redshift catalogs we estimate the completeness level of the CDF-S
spectroscopic coverage in several redshift bins. The completeness level is very
high, > 60%, at z < 3.5, and it is very uncertain at higher redshift. The
master catalog has been used also to estimate completeness and contamination
levels of different galaxy photometric selection techniques, such as the BzK,
the so called 'sub'-U-dropout and the drop-out methods and to identify large
scale structures in the field.


title:
Isotropic and Anisotropic Lattice Spacing Corrections for I=2 pi-pi
  Scattering from Effective Field Theory

abstract:
  The calculation of the finite lattice spacing corrections for I=2 pi-pi
scattering is carried out for isotropic and anisotropic Wilson lattice actions.
Pion masses and decay constants are also determined in this context. These
results correct the phase shift calculated from the lattice, which is connected
to the scattering length and effective range in this low energy scattering
process. When in terms of the lattice-physical parameters for either Wilson
action, these lattice spacing effects first appear at the next-to-leading order
counter-terms.


title: A New Approach to Spreadsheet Analytics Management in Financial Markets

abstract:
  Spreadsheets in financial markets are frequently used as database, calculator
and reporting application combined. This paper describes an alternative
approach in which spreadsheet design and database technology have been brought
together in order to alleviate management and regulatory concerns over the
operational risks of spreadsheet usage. In particular, the paper focuses on the
rapid creation and centralised deployment of statistical analytics within a
software system now in use by major investment banks, and presents a novel
technique for the manipulation in spreadsheets of high volumes of intraday
market data.


title: Suspended Graphene: a bridge to the Dirac point

abstract:
  The recent discovery of methods to isolate graphene, a one-atom-thick layer
of crystalline carbon, has raised the possibility of a new class of
nano-electronics devices based on the extraordinary electrical transport and
unusual physical properties of this material. However, the experimental
realization of devices displaying these properties was, until now, hampered by
the influence of the ambient environment, primarily the substrate. Here we
report on the fabrication of Suspended Graphene devices and on studies of their
electrical transport properties. In these devices, environmental disturbances
were minimized allowing unprecedented access to the intrinsic properties of
graphene close to the Dirac Point (DP) where the energy dispersion of the
carriers and their density-of-states vanish linearly giving rise to a range of
exotic physical properties. We show that charge inhomogeneity is reduced by
almost one order of magnitude compared to that in Non-Suspended Graphene
devices. Moreover, near the DP, the mobility exceeds 100,000 cm2/Vs,
approaching theoretical predictions for evanescent transport in the ballistic
model.


title: Charm Meson Decays

abstract:
  We review some recent developments in charm meson physics. In particular, we
discuss theoretical predictions and experimental measurements of charmed meson
decays to leptonic, semileptonic, and hadronic final states and implications of
such measurements to searches for new physics. We discuss D0-anti-D0-mixing and
CP-violation in charm, and discuss future experimental prospects and
theoretical challenges in this area.


title:
"On the Impossibility of a Poincare-Invariant Vacuum State with Unit
  Norm" Refuted

abstract: Assertions made in a document recently deposited in the arXiv are refuted.


title:
X-ray spectral variability in PG1535+547: the changing-look of a 'soft
  X-ray weak' AGN

abstract:
  PG1535+547 is a bright NLS1 galaxy, whose high energy emission shows strong
variability in shape and flux. ROSAT data classified it as soft X-ray weak QSO
(objects whose X-ray-to-optical flux ratio is smaller than in typical QSO):
their X-ray spectra are often characterized by highly ionized, complex
absorbers and/or reflection from the disk, whose relative importance is
currently debated. In both cases, the presence of such features implies that we
are looking at matter located in the innermost regions of the AGN. In this
paper we want to clarify the nature of the X-ray emission of PG1535+547, and
constrain the physical properties of regions where the emission originates. We
present new XMM observations, from which we obtained 2 spectra separated by
about 1 week, that we compare with a previous XMM observation. The data support
the complex and variable nature of the X-ray emission. The broad band flux
increases by a factor ~2.3 in 3 years, and then decreases by a factor ~1.3 in
about 1 week. In the new EPIC spectra strong absorption features at E<3keV and
a complex spectral shape in the Fe line energy range are evident, coupled with
a drop in the emission at higher energies. We describe all the states assuming
either a warm absorber plus a relativistically blurred ionized reflection, or a
two-phase warm absorber partially covering the source plus a scattered
component. The variability is ascribed to the warm absorbers, that vary their
physical properties on timescales of years and days. In the reflection scenario
all the states require a high fraction of reflection. The strong variability in
the X-ray band opposed to a more constant optical emission implies that
PG1535+547 can not actually be classified as a soft X-ray weak AGN.


title: Twisted conjugacy classes for polyfree groups

abstract:
  Let $G$ be a finitely generated polyfree group. If $G$ has nonzero Euler
characteristic then we show that $Aut(G)$ has a finite index subgroup in which
every automorphism has infinite Reidemeister number. For certain $G$ of length
2, we show that the number of Reidemeister classes of every automorphism is
infinite.


title: Power maps and subvarieties of the complex algebraic $n$--torus

abstract:
  Given a subvariety $V$ of the complex algebraic torus ${\mathbb G}_{\rm m}^n$
defined by polynomials of total degree at most $d$ and a power map $\phi:
{\mathbb G}_{\rm m}^n \to {\mathbb G}_{\rm m}^n$, the points ${\bf x}$ whose
forward orbits ${\mathcal O}_\phi({\bf x})$ belong to $V$ form its {\em stable}
subvariety $S(V,\phi)$. The main result of the paper provides an upper bound
$T=T(n,d,\phi)$ for the number of iterations of the power map $\phi$ required
to ``cut off'' the points of $V$ that do not belong to $S$.


title:
The Effect of Charon's Tidal Damping on the Orbits of Pluto's Three
  Moons

abstract:
  Pluto's recently discovered minor moons, Nix and Hydra, have almost circular
orbits, and are nearly coplanar with Charon, Pluto's major moon. This is
surprising because tidal interactions with Pluto are too weak to damp their
eccentricities. We consider an alternative possibility: that Nix and Hydra
circularize their orbits by exciting Charon's eccentricity via secular
interactions, and Charon in turn damps its own eccentricity by tidal
interaction with Pluto. The timescale for this process can be less than the age
of the Solar System, for plausible tidal parameters and moon masses. However,
as we show numerically and analytically, the effects of the 2:1 and 3:1
resonant forcing terms between Nix and Charon complicate this picture. In the
presence of Charon's tidal damping, the 2:1 term forces Nix to migrate outward
and the 3:1 term changes the eccentricity damping rate, sometimes leading to
eccentricity growth. We conclude that this mechanism probably does not explain
Nix and Hydra's current orbits. Instead, we suggest that they were formed
in-situ with low eccentricities.
  We also show that an upper limit on Nix's migration speed sets a lower limit
on Pluto-Charon's tidal circularization timescale of >10^5 yrs. Moreover,
Hydra's observed proper eccentricity may be explained by the 3:2 forcing by
Nix.


title: Non-Perturbative Effects of Geometry in Wide-Angle Redshift Distortions

abstract:
  We use the formalism of Szapudi(2004} to derive full explicit expressions for
the linear two-point correlation function, including redshift space distortions
and large angle effects. We take into account a non-perturbative geometric term
in the Jacobian, which is still linear in terms of the dynamics. This term had
been identified previously (Kaiser 1987,Hamilton and Culhane 1996), but has
been neglected in all subsequent explicit calculations of the linear redshift
space two-point correlation function. Our results represent a significant
correction to previous explicit expressions and are in excellent agreement with
our measurements in the Hubble Volume Simulation.


title: Optical Selection of Faint AGN in the COSMOS Field

abstract:
  We outline a strategy to select faint (i<24.5) type 1 AGN candidates down to
the Seyfert/QSO boundary for spectroscopic targeting in the COSMOS field,
picking candidates by their nonstellar colors in broadband ground-based
photometry and morphological properties extracted from HST-ACS. AGN optical
color selection has not been applied to such faint magnitudes in such a large
continuous part of the sky. Hot stars are known to be the dominant contaminant
for bright AGN candidate selection at z<2, but we anticipate the highest color
contamination at all redshifts to be from faint starburst and compact galaxies.
Morphological selection via the Gini Coefficient separates most potential AGN
from these faint blue galaxies. Recent models of the quasar luminosity function
are used to estimate quasar surface densities, and studies of stellar
populations in the COSMOS field infer stellar contamination. We use 292
spectroscopically confirmed type 1 AGN and quasar templates to predict AGN
colors with redshift, and contrast those predictions with the colors of known
contaminating populations. The motivation of this study and subsequent
spectroscopic follow-up is to populate and refine the faint end of the QLF
where the population of type 1 AGN is presently not well known. The anticipated
AGN observations will add to the ~300 already known AGN in the COSMOS field,
making COSMOS a densely packed field of quasars to be used to understand
supermassive black holes and probe the structure of the intergalactic medium in
the intervening volume.


title:
Muon spin rotation studies of electronic excitations and magnetism in
  the vortex cores of superconductors

abstract:
  The focus of this paper is on recent progress in muon spin rotation (muSR)
studies of the vortex cores in type-II superconductors. By comparison of muSR
measurements of the vortex core size in a variety of materials with results
from techniques that directly probe electronic states, the effect of
delocalized quasiparticles on the spatial variation of field in a lattice of
interacting vortices has been determined for both single-band and multi-band
superconductors. These studies demonstrate the remarkable accuracy of what some
still consider an exotic technique. In recent years muSR has also been used to
search for magnetism in and around the vortex cores of high-temperature
superconductors. As a local probe muSR is specially suited for detecting static
or quasistatic magnetism having short-range or random spatial correlations. As
discussed in this review, muSR experiments support a generic phase diagram of
competing superconducting and magnetic order parameters, characterized by a
quantum phase transition to a state where the competing order is spatially
nonuniform.


title: A deep X-ray observation of M82 with XMM-Newton

abstract:
  We report on the analysis of a deep (100 ks) observation of the starburst
galaxy M82 with the EPIC and RGS instruments on board the X-ray telescope
XMM-Newton. The broad-band (0.5-10 keV) emission is due to at least three
spectral components: i) continuum emission from point sources; ii) thermal
plasma emission from hot gas; iii) charge exchange emission from neutral metals
(Mg and Si). The plasma emission has a double-peaked differential emission
measure, with the peaks at ~0.5 keV and ~7 keV. Spatially resolved spectroscopy
has shown that the chemical absolute abundances are not uniformly distributed
in the outflow, but are larger in the outskirts and smaller close to the galaxy
centre. The abundance ratios also show spatial variations. The X-ray derived
Oxygen abundance is lower than that measured in the atmospheres of red
supergiant stars, leading to the hypothesis that a significant fraction of
Oxygen ions have already cooled off and no longer emit at energies > ~0.5 keV.


title: Structural Analysis of Molecular Clouds: Dendrograms

abstract:
  We demonstrate the utility of dendrograms at representing the essential
features of the hierarchical structure of the isosurfaces for molecular line
data cubes. The dendrogram of a data cube is an abstraction of the changing
topology of the isosurfaces as a function of contour level. The ability to
track hierarchical structure over a range of scales makes this analysis
philosophically different from local segmentation algorithms like CLUMPFIND.
Points in the dendrogram structure correspond to specific volumes in data cubes
defined by their bounding isosurfaces. We further refine the technique by
measuring the properties associated with each isosurface in the analysis
allowing for a multiscale calculation of molecular gas properties. Using
COMPLETE 13CO(1-0) data from the L1448 region in Perseus and mock observations
of a simulated data cube, we identify regions that have a significant
contribution by self-gravity to their energetics on a range of scales. We find
evidence for self-gravitation on all spatial scales in L1448 though not in all
regions. In the simulated observations, nearly all of the emission is found in
objects that would be self-gravitating if gravity were included in the
simulation. We reconstruct the size-line width relationship within the data
cube using the dendrogram-derived properties and find it follows the standard
relation: s_v ~ R^0.58. Finally, we show that constructing the dendrogram of CO
J=1-0 emission from the Orion-Monoceros region allows for the identification of
giant molecular clouds in a blended molecular line data set using only a
physically motivated definition (self-gravitating clouds with masses 5x10^4
Msun.


title: 'Slow' and Fast Rotators among Hypervelocity Stars

abstract:
  We measure the projected rotational velocities of the late B-type
hypervelocity stars HVS7 and HVS8 from high resolution spectroscopy to be 60
+/- 17 km/s and 260 +/- 70 km/s. The 'slow' rotation of HVS7 is in principle
consistent with having originated in a binary system, assuming a high
inclination angle of the stellar rotation axis. However, the fast rotation of
HVS8 is more typical of single B-type stars. HVS8 could have therefore been
ejected by a mechanism other than that proposed by Hills. We also estimate the
effective temperatures and surface gravities for HVS7 and HVS8 and obtain an
additional measurement of their radial velocities. We find evidence in support
of a blue horizontal branch nature for HVS7, and a main sequence nature for
HVS8.


title: Dimensions of Supersymmetric Operators from AdS/CFT

abstract:
  We examine the AdS/CFT correspondence through a manifestly 5D supersymmetric
formalism, corresponding to a 4D N=1 supersymmetric CFT. We find that the
dimensions of scalar and fermionic component operators are simply related, and
that there is a smooth transition of scalar operator dimensions through the
value d_s = 2. By using this formalism, we also show that the formula used in
the string literature for the dimension of fermion operators is incomplete.


title:
Decay dynamics of quantum dots influenced by the local density of
  optical states of two-dimensional photonic crystal membranes

abstract:
  We have performed time-resolved spectroscopy on InAs quantum dot ensembles in
photonic crystal membranes. The influence of the photonic crystal is
investigated by varying the lattice constant systematically. We observe a
strong slow down of the quantum dots' spontaneous emission rates as the
two-dimensional bandgap is tuned through their emission frequencies. The
measured band edges are in full agreement with theoretical predictions. We
characterize the multi-exponential decay curves by their mean decay time and
find enhancement of the spontaneous emission at the bandgap edges and strong
inhibition inside the bandgap in good agreement with local density of states
calculations.


title: Heat Content, Heat Trace, and Isospectrality

abstract:
  We study the heat content function, the heat trace function, and questions of
isospectrality for the Laplacian with Dirichlet boundary conditions on a
compact manifold with smooth boundary in the context of finite coverings and
warped products.


title: Nonlinear ac conductivity of one-dimensional Mott insulators

abstract:
  We discuss a semiclassical calculation of low energy charge transport in
one-dimensional (1d) insulators with a focus on Mott insulators, whose charge
degrees of freedom are gapped due to the combination of short range
interactions and a periodic lattice potential. Combining RG and instanton
methods, we calculate the nonlinear ac conductivity and interpret the result in
terms of multi-photon absorption. We compare the result of the semiclassical
calculation for interacting systems to a perturbative, fully quantum mechanical
calculation of multi-photon absorption in a 1d band insulator and find good
agreement when the number of simultaneously absorbed photons is large.


title: Looking Beyond Content: Skill development for engineers

abstract:
  Current concerns over reforming engineering education have focused attention
on helping students develop skills and an adaptive expertise. Phenomenological
guidelines for instruction along these lines can be understood as arising out
of an emerging theory of thinking and learning built on results in the neural,
cognitive, and behavioral sciences. We outline this framework and consider some
of its implications for one example: developing a more detailed understanding
of the specific skill of using mathematics in modeling physical situations.
This approach provides theoretical underpinnings for some best-practice
instructional methods designed to help students develop this skill and
providesguidance for further research in the area.


title: On the Origin of Pluto's Minor Moons, Nix and Hydra

abstract:
  How did Pluto's recently discovered minor moons form? Ward and Canup propose
an elegant solution in which Nix and Hydra formed in the collision that
produced Charon, then were caught into corotation resonances with Charon, and
finally were transported to their current location as Charon migrated outwards.
We show with numerical integrations that, if Charon's eccentricity is
judiciously chosen, this scenario works beautifully for either Nix or Hydra.
However, it cannot work for both Nix and Hydra simultaneously. To transport
Nix, Charon's eccentricity must satisfy e_C< 0.024; otherwise, the second order
Lindblad resonance at 4:1 overlaps with the corotation resonance, leading to
chaos. To transport Hydra, e_C > 0.7 R_p/a_C > 0.04; otherwise migration would
be faster than libration, and Hydra would slip out of resonance. These two
restrictions conflict. Having ruled out this scenario, we suggest an
alternative: that many small bodies were captured from the nebular disk, and
they were responsible for forming, migrating and damping Nix and Hydra. If this
is true, small moons could be common around large Kuiper belt objects.


title: Improved search for D^0 mixing using semileptonic decays at Belle

abstract:
  A search for mixing in the neutral D meson system has been performed using
semileptonic D0 -> K(*)- e+ \nu and D0 -> K(*)- \mu+ \nu decays. Neutral D
mesons from D*+ -> D0 \pi_s^+ decays are used and the flavor at production is
tagged by the charge of the slow pion. The measurement is performed using 492
fb^-1 of data recorded by the Belle detector. From the yield of right-sign and
wrong-sign decays arising from non-mixed and mixed events, respectively, we
measure the ratio of the time-integrated mixing rate to the unmixed rate to be
R_M = (1.3 +- 2.2 +- 2.0) x 10^-4. This corresponds to an upper limit of R_M <
6.1 x 10^-4 at the 90% C.L.


title: Anomalous Magnetic Properties of Sr2YRuO6

abstract:
  Anomalous magnetic properties of the double perovskite ruthenates compound
Sr2YRuO6 are reported here. Magnetization measurements as a function of
temperature in low magnetic fields show clear evidence for two components of
magnetic order (TM1 ~ 32K and TM2 ~ 27K) aligned opposite to each other with
respect to the magnetic field direction even though only Ru5+moments can order
magnetically in this compound. The second component of the magnetic order at
TM2 ~ 27K results only in a magnetization reversal, and not in the negative
magnetization when the magnetization is measured in the field cooled (FC) mode.
Isothermal magnetization (M-H) measurements show hysteresis with maximum
coercivity (Hc) and remnant magnetization (Mr) at T ~ 27 K, corroborating the
presence of the two oppositely aligned magnetic moments, each with a
ferromagnetic component. The two components of magnetic ordering are further
confirmed by the double peak structure in the heat capacity measurements. These
anomalous properties have significance to some of the earlier results obtained
for the Cu-substituted superconducting Sr2YRu1-xCuxO6 compounds.


title: Gluon multiplicity in coherent diffraction of onium on a heavy nucleus

abstract:
  We derive the cross section for the diffractive gluon production in high
energy onium-nucleus collisions that includes the low-x evolution effects in
the rapidity interval between the onium and the produced gluon and in the
rapidity interval between the gluon and the target nucleus. We analyze our
result in two limiting cases: when the onium size is much smaller than the
saturation scale and when its size is much larger than the saturation scale. In
the later case the gluon multiplicity is very small in the quasi-classical case
and increases when the low-x evolution effects in onium become significant. We
discuss the implications of our result for the RHIC, LHC and EIC phenomenology.


title:
Solving the Bethe-Salpeter equation for a pseudoscalar meson in
  Minkowski space

abstract:
  A new method of solution of the Bethe-Salpeter equation for a pseudoscalar
quark-antiquark bound state is proposed. With the help of an integral
representation, the results are directly obtained in Minkowski space. Dressing
of Green's functions is naturally taken into account, thus providing the
possible inclusion of a running coupling constant as well as quark propagators.
First numerical results are presented for a simplified ladder approximation.


title: Remarks on Heavy-Light Mesons from AdS/CFT

abstract:
  We use the AdS/CFT correspondence to compute the energy spectrum of
heavy-light mesons in a N=2 SU(N) super Yang-Mills theory with two massive
hypermultiplets. In the heavy quark limit, similar to QCD, we find that the
excitation energies are independent of the heavy quark mass. We also make some
remarks about related AdS/CFT models of flavor with less supersymmetry.


title: Model X-ray Spectra of Magnetic Neutron Stars with Hydrogen Atmospheres

abstract:
  We construct partially ionized hydrogen atmosphere models for magnetized
neutron stars in radiative equilibrium with fixed surface fields between
B=10^12 and 2x10^13 G and effective temperatures logT_eff=5.5-6.8, as well as
with surface B and T_eff distributions around these values. The models are
based on the latest equation of state and opacity results for magnetized,
partially ionized hydrogen plasmas. The atmospheres directly determine the
characteristics of thermal emission from the surface of neutron stars. We also
incorporate these model spectra into XSPEC, under the model name NSMAX, thus
allowing them to be used by the community to fit X-ray observations of neutron
stars.


title: Dangerous Angular KK/Glueball Relics in String Theory Cosmology

abstract:
  The presence of Kaluza-Klein particles in the universe is a potential
manifestation of string theory cosmology. In general, they can be present in
the high temperature bath of the early universe. In particular examples, string
theory inflation often ends with brane-antibrane annihilation followed by the
energy cascading through massive closed string loops to KK modes which then
decay into lighter standard model particles. However, massive KK modes in the
early universe may become dangerous cosmological relics if the inner manifold
contains warped throat(s) with approximate isometries. In the complimentary
picture, in the AdS/CFT dual gauge theory with extra symmetries, massive
glueballs of various spins become the dangerous cosmological relics. The decay
of these angular KK modes/glueballs, located around the tip of the throat, is
caused by isometry breaking which results from gluing the throat to the compact
CY manifold. We address the problem of these angular KK particles/glueballs,
studying their interactions and decay channels, from the theory side, and the
resulting cosmological constraints on the warped compactification parameters,
from the phenomenology side. The abundance and decay time of the long-lived
non-relativistic angular KK modes depend strongly on the parameters of the
warped geometry, so that observational constraints rule out a significant
fraction of the parameter space. In particular, the coupling of the angular KK
particles can be weaker than gravitational.


title:
Tellipsoid: Exploiting inter-gene correlation for improved detection of
  differential gene expression

abstract:
  Motivation: Algorithms for differential analysis of microarray data are vital
to modern biomedical research. Their accuracy strongly depends on effective
treatment of inter-gene correlation. Correlation is ordinarily accounted for in
terms of its effect on significance cut-offs. In this paper it is shown that
correlation can, in fact, be exploited {to share information across tests},
which, in turn, can increase statistical power.
  Results: Vastly and demonstrably improved differential analysis approaches
are the result of combining identifiability (the fact that in most microarray
data sets, a large proportion of genes can be identified a priori as
non-differential) with optimization criteria that incorporate correlation. As a
special case, we develop a method which builds upon the widely used two-sample
t-statistic based approach and uses the Mahalanobis distance as an optimality
criterion. Results on the prostate cancer data of Singh et al. (2002) suggest
that the proposed method outperforms all published approaches in terms of
statistical power.
  Availability: The proposed algorithm is implemented in MATLAB and in R. The
software, called Tellipsoid, and relevant data sets are available at
http://www.egr.msu.edu/~desaikey


title: A Generic Surface Sampler for Monte Carlo Simulations

abstract:
  We present an implementation of a Monte Carlo algorithm that generates points
randomly and uniformly on a set of arbitrary surfaces. The algorithm is
completely general and only requires the geometry modeling software to provide
the intersection points of an arbitrary line with the surface being sampled. We
demonstrate the algorithm using the Geant4 Monte Carlo simulation toolkit. The
efficiency of the sampling algorithm is discussed, along with various options
in the implementation and example applications.


title: Bulk Flow and Shear Moments of the SFI++ Survey

abstract:
  We find the nine bulk--flow and shear moments from the SFI++ survey, as well
as for subsamples of group and field galaxies. We constrain the velocity power
spectrum shape parameter $\Gamma$ in linear theory using these moments. A
likelihood function for $\Gamma$ was found after marginalizing over the power
spectrum amplitude $\sigma_8\Omega_m^{0.6}$ using constraints obtained from
comparisons between redshift surveys and peculiar velocity data. We have
estimated the velocity noise $\sigma_*$ from the data since without it our
results may be biased. We also performed a statistical analysis of the
difference between the field and group catalogues and found that the results
from each reflect the same underlying large scale flows. We found that we can
constrain the power spectrum shape parameter to be
$\Gamma=0.15^{+0.18}_{-0.08}$ for the groups catalogue and
$\Gamma=0.09^{+0.04}_{-0.04}$ for the field galaxy catalogue in fair agreement
with the value from WMAP.


title: Leptogenesis

abstract:
  Leptogenesis is a class of scenarios where the baryon asymmetry of the
Universe is produced from a lepton asymmetry generated in the decays of a heavy
sterile neutrino. We explain the motivation for leptogenesis. We review the
basic mechanism, and describe subclasses of models. We then focus on recent
developments in the understanding of leptogenesis: finite temperature effects,
spectator processes, and in particular the significance of flavor physics.


title: X-ray Observations of Parsec-Scale Tails behind Two Middle-Aged Pulsars

abstract:
  Chandra and XMM-Newton resolved extremely long tails behind two middle-aged
pulsars, J1509-5850 and J1740+1000. The tail of PSR J1509-5850 is discernible
up to 5.6' from the pulsar (6.5 pc at a distance of 4 kpc), with a flux of
2*10^{-13} erg s^{-1} cm^{-2} in 0.5-8 keV. The tail spectrum fits an absorbed
power-law (PL) model with the photon index of 2.3\pm0.2, corresponding to the
0.5-8 keV luminosity of 1*10^{33} ergs s^{-1}, for n_H= 2.1*10^{22} cm^{-2}.
The tail of PSR J1740+1000 is firmly detected up to 5' (2 pc at a 1.4 kpc
distance), with a flux of 6*10^{-14} ergs cm^{-2} s^{-1} in 0.4-10 keV. The PL
fit yields photon index of 1.4-1.5 and n_H=1*10^{21} cm^{-2}. The large extent
of the tails suggests that the bulk flow in the tails starts as mildly
relativistic downstream of the termination shock, and then gradually
decelerates. Within the observed extent of the J1509-5850 tail, the average
flow speed exceeds 5,000 km s^{-1}, and the equipartition magnetic field is a
few times 10^{-5} G. For the J1740+1000 tail, the equipartition field is a
factor of a few lower. The harder spectrum of the J1740+1000 tail implies
either less efficient cooling or a harder spectrum of injected electrons. For
the high-latitude PSR J1740+1000, the orientation of the tail on the sky shows
that the pulsar is moving toward the Galactic plane, which means that it was
born from a halo-star progenitor. The comparison between the J1509 and J1740
tails and the X-ray tails of other pulsars shows that the X-ray radiation
efficiency correlates poorly with the pulsar spin-down luminosity or age. The
X-ray efficiencies of the ram-pressure confined pulsar wind nebulae (PWNe) are
systematically higher than those of PWNe around slowly moving pulsars with
similar spin-down parameters.


title: The Molecular Environment of the Gamma-ray Source TeV J2032+4130

abstract:
  The mysterious very high energy gamma-ray source, TeV J2032+4130, is
coincident with the powerful Cygnus OB2 stellar association, though a physical
association between the two remains uncertain. It is possible that the detected
very high energy photons are produced via an overdensity of locally accelerated
cosmic rays impinging on molecular clouds in the source region. In order to
test this hypothesis, we used the Kitt Peak 12m, the Heinrich-Hertz
Submillimeter Telescope (HH-SMT), and the Five College Radio Astronomy
Observatory (FCRAO), to obtain observations in the J=1-->0 and J=2-->1 lines of
both 12CO and 13CO. We report here on the detection of significant molecular
material toward the TeV source region which could be acting as the target of
locally accelerated CRs. We also find evidence of compact molecular clumps,
showing large line widths in the CO spectra, possibly indicative of energetic
processes in this region of Cygnus OB2.


title: Single Top Quark Production at the Fermilab Tevatron Collider

abstract:
  First evidence for single top quark production has recently been found by
both the D0 and CDF experiments. By combining three analyses, D0 measured a
cross section of 4.7 +- 1.3 pb, with a significance of 3.6 standard deviations,
and CDF's matrix elements analysis measured a cross section of 3.0 +1.2 -1.1
pb, with a significance of 3.1 standard deviations. These analyses also
provided the first direct measurements of the CKM matrix element, |Vtb|,
without assuming unitarity. This talk briefly describes the latest single top
production results from the two experiments.


title:
No periodicity revealed for an "eclipsing" ultraluminous supersoft X-ray
  source in M81

abstract:
  Luminous supersoft X-ray sources found in the Milky Way and Magellanic Clouds
are likely white dwarfs that steadily or cyclically burn accreted matter on
their surface, which are promising type Ia supernova progenitors. Observations
of distant galaxies with Chandra and XMM-Newton have revealed supersoft sources
that are generally hotter and more luminous, including some ultraluminous
supersoft sources (ULSs) that are possibly intermediate mass black holes of a
few thousand solar masses. In this paper we report our X-ray spectral and
timing analysis for M81-ULS1, an ultraluminous supersoft source in the nearby
spiral galaxy M81. M81-ULS1 has been persistently supersoft in 17 Chandra ACIS
observations spanning six years, and its spectrum can be described by either a
$kT_{bb}\approx70$ eV blackbody for a $\sim1.2M_\odot$ white dwarf, or a
$kT_{in} \approx 80$ eV multicolor accretion disk for a $\gtrsim10^3M_\odot$
intermediate mass black hole. In two observations, the light curves exhibited
dramatic flux drop/rise on time scales of $10^3$ seconds, reminiscent of
eclipse ingress/egress in eclipsing X-ray binaries. However, the exhaustive
search for periodicity in the reasonable range of 50 ksec to 50 days failed to
reveal an orbital period. The failure to reveal any periodicity is consistent
with the long period ($\ge30$ yrs) predicted for this system given the optical
identification of the secondary with an asymptotic giant star. Also, the
eclipse-like dramatic flux changes in hours are hard to explain under the white
dwarf model, but can in principle be explained by disk temperature changes
induced by accretion rate variations under the intermediate mass black hole
model.


title: Hebbian Crosstalk Prevents Nonlinear Unsupervised Learning

abstract:
  Learning is thought to occur by localized, experience-induced changes in the
strength of synaptic connections between neurons. Recent work has shown that
activity-dependent changes at one connection can affect changes at others
(crosstalk). We studied the role of such crosstalk in nonlinear Hebbian
learning using a neural network implementation of Independent Components
Analysis (ICA). We find that there is a sudden qualitative change in the
performance of the network at a critical crosstalk level and discuss the
implications of this for nonlinear learning from higher-order correlations in
the neocortex.


title:
Determining the Dark Matter Relic Density in the Minimal Supergravity
  Stau-Neutralino Coannihilation Region at the Large Hadron Collider

abstract:
  We examine the stau-neutralino coannihilation (CA) mechanism of the early
universe. We use the minimal supergravity (mSUGRA) model and show that from
measurements at the Large Hadron Collider one can predict the dark matter relic
density with an uncertainty of 6% with 30 fb-1 of data, which is comparable to
the direct measurement by Wilkinson Microwave Anisotropy Probe. This is done by
measuring four mSUGRA parameters m0, m1/2, A0 and tan(beta) without requiring
direct measurements of the top squark and bottom squark masses. We also provide
precision measurements of the gaugino, squark, and lighter stau masses in this
CA region without assuming gaugino universality.


title: Model Building with F-Theory

abstract:
  Despite much recent progress in model building with D-branes, it has been
problematic to find a completely convincing explanation of gauge coupling
unification. We extend the class of models by considering F-theory
compactifications, which may incorporate unification more naturally. We explain
how to derive the charged chiral spectrum and Yukawa couplings in N=1
compactifications of F-theory with G-flux. In a class of models which admit
perturbative heterotic duals, we show that the F-theory and heterotic
computations match.


title:
Opacity in compact extragalactic radio sources and its effect on
  astrophysical and astrometric studies

abstract:
  The apparent position of the "core" in a parsec-scale radio jet (a compact,
bright emitting region at the narrow end of the jet) depends on the observing
frequency, owing to synchrotron self-absorption and external absorption. While
providing a tool probing physical conditions in the vicinity of the core, this
dependency poses problems for astrometric studies using compact radio sources.
We investigated the frequency-dependent shift in the positions of the cores
(core shift) observed with very long baseline interferometry (VLBI) in
parsec-scale jets. We discuss related physics, as well as its effect on radio
astrometry and the connection between radio and optical positions of
astrometric reference objects. We searched for the core shift in a sample of
277 radio sources imaged at 2.3 GHz (13 cm) and 8.6 GHz (4 cm) frequency bands
using VLBI observations made in 2002 and 2003. The core shift was measured by
referencing the core position to optically thin jet features whose positions
are not expected to change with frequency. We present here results for 29
selected active galactic nuclei (AGN) with bright distinct VLBI jet features
that can be used in differential measurements and that allow robust
measurements of the shift to be made. In these AGN, the magnitude of the
measured core shift between 2.3 and 8.6 GHz reaches 1.4 mas, with a median
value for the sample of 0.44 mas. Nuclear flares result in temporal variability
of the shift. An average shift between the radio (4 cm) and optical (6000
Angstrom) bands is estimated to be approximately 0.1 mas, and it should be
taken into account in order to provide the required accuracy of the
radio-optical reference frame connection. This can be accomplished with
multi-frequency VLBI measurements... (abridged)


title: Myron Mathisson: what little we know of his life

abstract:
  Myron Mathisson (1897-1940) was a Polish Jew known for his work on the
equations of motion of bodies in general relativity and for developing a new
method to analyze the properties of fundamental solutions of linear hyperbolic
differential equations. In particular, he derived the equations for a spinning
body moving in a gravitational field and proved, in a special case, the
Hadamard conjecture on the class of equations that satisfy the Huygens
principle. His work still exerts influence on current research. Drawing on
various archival and secondary sources, in particular his correspondence with
Einstein, we outline Mathisson's biography and scientific career.


title:
Screening of point charge impurities in highly anisotropic metals:
  application to $\mu^+$ spin relaxation in underdoped cuprates

abstract:
  We calculate the screening charge density distribution due to a point charge,
such as that of a positive muon ($\mu^+$), placed between the planes of a
highly anisotropic layered metal. In underdoped hole cuprates the screening
charge converts the charge density in the metallic-plane unit cells in the
vicinity of the $\mu^+$ to nearly its value in the insulating state. The
current-loop ordered state observed by polarized neutron diffraction then
vanishes in such cells, and also in nearby cells over a distance of order the
intrinsic correlation length of the loop-ordered state. This in turn strongly
suppresses the loop-current field at the $\mu^+$ site. We estimate this
suppressed field in underdoped YBa$_2$Cu$_3$O$_{6+x}$ and
La$_{2-x}$Sr$_x$CuO$_4$, and find consistency with the observed 0.2--0.3 G
field in the former case and the observed upper bound of $\sim$0.2 G in the
latter case. This resolves the controversy between the neutron diffraction and
$\mu$SR experiments. The screening calculation also has relevance for the
effect of other charge impurities in the cuprates, such as the dopants
themselves.


title:
Glauber Gluons in Soft Collinear Effective Theory and Factorization of
  Drell-Yan Processes

abstract:
  Glauber gluons in Drell-Yan processes are soft gluons with the transverse
momenta much larger than their momentum components along the directions of
initial hadrons. Their existence has been a serious challenge in proving the
factorization of Drell-Yan processes. The recently proposed soft collinear
effect theory of QCD can provide a transparent way to show factorizations for a
class of processes, but it does not address the effect of glauber gluons. In
this letter we first confirm the existence of glauber gluons through an
example. We then add glauber gluons into the effective theory and study their
interaction with other particles. In the framework of the effective theory with
glauber gluons we are able to show that the effects of glauber gluons in
Drell-Yan processes are canceled and the factorization holds in the existence
of glauber gluons. Our work completes the proof or argument of factorization of
Drell-Yan process in the framework of the soft collinear effective theory.


title: Nanogaps with very large aspect ratios for electrical measurements

abstract:
  For nanoscale electrical characterization and device fabrication it is often
desirable to fabricate planar metal electrodes separated by large aspect ratio
gaps with interelectrode distances well below 100 nm. We demonstrate a
self-aligned process to accomplish this goal using a thin Cr film as a
sacrificial etch layer. The resulting gaps can be as small as 10 nm and have
aspect ratios exceeding 1000, with excellent interelectrode isolation. Such
Ti/Au electrodes are demonstrated on Si substrates and are used to examine a
voltage-driven transition in magnetite nanostructures. This shows the utility
of this fabrication approach even with relatively reactive substrates.


title:
Hard Fairness Versus Proportional Fairness in Wireless Communications:
  The Multiple-Cell Case

abstract:
  We consider the uplink of a cellular communication system with $K$ users per
cell and infinite base stations equally spaced on a line. The system is
conventional, i.e., it does not make use of joint cell-site processing. A hard
fairness (HF) system serves all users with the same rate in any channel state.
In contrast, a system based on proportional fairness serves the users with
variable instantaneous rates depending on their channel state. We compare these
two options in terms of the system spectral efficiency \textsf{C} (bit/s/Hz)
versus $E_b/N_0$. Proportional fair scheduling (PFS) performs generally better
than the more restrictive HF system in the regime of low to moderate SNR, but
for high SNR an optimized HF system achieves throughput comparable to that of
PFS system for finite $K$. The hard-fairness system is interference limited. We
characterize this limit and validate a commonly used simplified model that
treats outer cell interference power as proportional to the in-cell total power
and we analytically characterize the proportionality constant. In contrast, the
spectral efficiency of PFS can grow unbounded for $K \to \infty$ thanks to the
multiuser diversity effect. We also show that partial frequency/time reuse can
mitigate the throughput penalty of the HF system, especially at high SNR.


title: Six-Dimensional Yang Black Holes in Dilaton Gravity

abstract:
  We study the six-dimensional dilaton gravity Yang black holes of
hep-th/0607193, which carry (1,-1) charge in SU(2)xSU(2) gauge group. We find
what values of the asymptotic parameters (mass and scalar charge) lead to a
regular horizon, and show that there are no regular solutions with an extremal
horizon.


title:
Redetermination of the space weathering rate using spectra of Iannini
  asteroid family members

abstract: Rewriting a shorter abstract.


title:
A remark on the boundedness and convergence properties of smooth sliding
  mode controllers

abstract:
  Conventional sliding mode controllers are based on the assumption of
switching control but a well-known drawback of this approach is the chattering
phenomenon. To overcome the undesirable chattering effects, the discontinuity
in the control law can be smoothed out in a thin boundary layer neighboring the
switching surface. In this work, rigorous proofs of the boundedness and
convergence properties of smooth sliding mode controllers are presented. This
result corrects flawed conclusions previously reached in the literature.


title: Scalar Nonets in Pole-Dominated QCD Sum Rules

abstract:
  The light scalar nonets are studied using the QCD sum rules for the
tetraquark operators. The operator product expansion for the correlators is
calculated up to dimension 12 and this enables us to perform analyses retaining
sufficient pole-dominance. To classify the light scalar nonets, we investigate
the dependence on current quark mass and flavor dynamics. Especially, to
examine the latter, we study separately SU(3) singlet and octet states, and
show that the number of annihilation diagrams is largely responsible for their
differences, which is also the case even after the inclusion of the finite
quark mass. Our results support the tetraquark picture for isosinglets, while
that for octets is not conclusive yet.


title: Characterization of Cobweb Posets as KoDAGs

abstract:
  The characterization of the large family of cobweb posets as DAGs and oDAGs
is given. The dim 2 poset such that its Hasse diagram coincide with digraf of
arbitrary cobweb poset is constructed.


title: Weyl groups, lattices and geometric manifolds

abstract:
  By studying the action of the Weyl group of a simple Lie algebra on its root
lattice, we construct torsion free subgroups of small and explicitly determined
index in a large infinite class of Coxeter groups. One spin-off is the
construction of hyperbolic manifolds of very small volume in up to 8
dimensions.


title: Production of X(3872) at PANDA

abstract:
  The recently discovered $X$(3872) has many possible interpretations. We study
the production of $X$(3872) with PANDA at GSI for the antiproton-proton
collision with two possible interpretations of X(3872). One is as a
loosely-bound molecule of $D$-mesons, while another is a 2P charmonium state
$\chi_{c1}$ (2P). Using effective couplings we are able to give numerical
predictions for the production near the threshold and the production associated
with $\pi^0$. The produced $X$(3872) can be identified with its decay $J/\psi
\pi^+\pi^-$. We also study the possible background near the threshold
production for $X(3872) \to J/\psi \pi^+\pi^-$. With the designed luminosity
$1.5{\rm fb}^{-1}$ per year of PANDA we find that the event number of $p\bar p
\to J/\psi \pi^+\pi^-$ near the threshold is at the order of $10^6 \sim 10^8$,
where the large uncertainty comes from the total decay width of X(3872). Our
study shows that at the threshold more than about 60% events come from the
decay of X(3872) and two interpretations are distinguishable from the
line-shape of the production. With our results we except that the PANDA
experiments will shed light on the property of X(3872).


title: Relativistic stars with purely toroidal magnetic fields

abstract:
  We investigate the effects of the purely toroidal magnetic field on the
equilibrium structures of the relativistic stars. The master equations for
obtaining equilibrium solutions of relativistic rotating stars containing
purely toroidal magnetic fields are derived for the first time. To solve these
master equations numerically, we extend the Cook-Shapiro-Teukolsky scheme for
calculating relativistic rotating stars containing no magnetic field to
incorporate the effects of the purely toroidal magnetic fields. By using the
numerical scheme, we then calculate a large number of the equilibrium
configurations for a particular distribution of the magnetic field in order to
explore the equilibrium properties. We also construct the equilibrium sequences
of the constant baryon mass and/or the constant magnetic flux, which model the
evolution of an isolated neutron star as it loses angular momentum via the
gravitational waves. Important properties of the equilibrium configurations of
the magnetized stars obtained in this study are summarized as follows ; (1) For
the non-rotating stars, the matter distribution of the stars is prolately
distorted due to the toroidal magnetic fields. (2) For the rapidly rotating
stars, the shape of the stellar surface becomes oblate because of the
centrifugal force. But, the matter distribution deep inside the star is
sufficiently prolate for the mean matter distribution of the star to be
prolate. (3) The stronger toroidal magnetic fields lead to the mass-shedding of
the stars at the lower angular velocity. (4) For some equilibrium sequences of
the constant baryon mass and magnetic flux, the stars can spin up as they lose
angular momentum.


title: Nuclear Constraints on the Weak Nucleon-Nucleon Interaction

abstract:
  I discuss the current status of efforts to constrain the
strangeness-conserving weak hadronic interaction, which can be isolated in
nuclear systems because of the associated parity violation.


title:
Evidence for a disorder driven phase transition in the condensation of
  4He in aerogels

abstract:
  We report on thermodynamic and optical measurements of the condensation
process of $^4$He in three silica aerogels of different microstructures. For
the two base-catalysed aerogels, the temperature dependence of the shape of
adsorption isotherms and of the morphology of the condensation process show
evidence of a disorder driven transition, in agreement with recent theoretical
predictions. This transition is not observed for a neutral-catalysed aerogel,
which we interpret as due to a larger disorder in this case.