title:
Probing two-fluid hydrodynamics in a trapped Fermi superfluid at
  unitarity

abstract:
  We develop a variational approach to calculate the density response function
at finite temperatures of the lowest-lying two-fluid modes in a trapped
two-component Fermi superfluid close to a Feshbach resonance. The out-of-phase
oscillations, which are the analogue in trapped gases of second sound in
uniform superfluids, have so far not been observed in cold-atom experiments. At
unitarity, we show that these modes are observable at finite temperatures via
two-photon Bragg scattering, whose spectrum is related to the imaginary part of
density response function. This provides direct evidence for superfluidity and
a promising way to test microscopic results for thermodynamics at unitarity.


title:
Optical-approximation analysis of sidewall-spacing effects on the force
  between two squares with parallel sidewalls

abstract:
  Using the ray-optics approximation, we analyze the Casimir force in a two
dimensional domain formed by two metallic blocks adjacent to parallel metallic
sidewalls, which are separated from the blocks by a finite distance h. For h >
0, the ray-optics approach is not exact because diffraction effects are
neglected. Nevertheless, we show that ray optics is able to qualitatively
reproduce a surprising effect recently identified in an exact numerical
calculation: the force between the blocks varies non-monotonically with h. In
this sense, the ray-optics approach captures an essential part of the physics
of multi-body interactions in this system, unlike simpler pairwise-interaction
approximations such as PFA. Furthermore, by comparison to the exact numerical
results, we are able to quantify the impact of diffraction on Casimir forces in
this geometry.


title: Abundance of elliptic dynamics on conservative 3-flows

abstract:
  We consider a compact 3-dimensional boundaryless Riemannian manifold M and
the set of divergence-free (or zero divergence) vector fields without
singularities, then we prove that this set has a C1-residual such that any
vector field inside it is Anosov or else its elliptical orbits are dense in the
manifold M.


title: Statistical mechanics of non-hamiltonian systems: Traffic flow

abstract:
  Statistical mechanics of a small system of cars on a single-lane road is
developed. The system is not characterized by a Hamiltonian but by a
conditional probability of a velocity of a car for the given velocity and
distance of the car ahead. Distribution of car velocities for various densities
of a group of cars are derived as well as probabilities of density fluctuations
of the group for different velocities. For high braking abilities of cars
free-flow and congested phases are found. Platoons of cars are formed for
system of cars with inefficient brakes. A first order phase transition between
free-flow and congested phase is suggested.


title:
On two-component contact model in continuum with one independent
  component

abstract:
  Properties of a contact process in continuum for a system of two type
particles one type of which is independent are considered. We study dynamics of
the first and second order correlation functions, their asymptotics and
dependence on parameters of the system.


title: Modules of covariants in modular invariant theory

abstract:
  Let the finite group $G$ act linearly on the vector space $V$ over the field
$k$ of arbitrary characteristic. If $H<G$ is a subgroup the extension of
invariant rings $k[V]^G\subset k[V]^H$ is studied using modules of covariants.
  An example of our results is the following. Let $W$ be the subgroup of $G$
generated by the reflections in $G$. A classical theorem due to Serre says that
if $k[V]$ is a free $k[V]^G$-module then $G=W$. We generalize this result as
follows. If $k[V]^H$ is a free $k[V]^G$-module then $G$ is generated by $H$ and
$W$, and the invariant ring $k[V]^{H\cap W}$ is free over $k[V]^W$ and
generated as an algebra by $H$-invariants and $W$-invariants.


title: White Paper on the Status and Future of Ground-based Gamma-ray Astronomy

abstract:
  In recent years, ground-based gamma-ray observatories have made a number of
important astrophysical discoveries which have attracted the attention of the
wider scientific community. The Division of Astrophysics of the American
Physical Society has requested the preparation of a white paper on the status
and future of ground-based gamma-ray astronomy to define the science goals of
the future observatory, to determine the performance specifications, and to
identify the areas of necessary technology development. In this contribution we
give a brief overview of the activities of the current white paper team and
invite the international community to contribute to the white paper.


title:
Search for resonant ttbar production in ppbar collisions at sqrt{s}=1.96
  TeV

abstract:
  We report on a search for narrow-width particles decaying to a top and
antitop quark pair. The data set used in the analysis corresponds to an
integrated luminosity of 680 pb^{-1} collected with the Collider Detector at
Fermilab in Run II. We present 95% confidence level upper limits on the cross
section times branching ratio. Assuming a specific topcolor-assisted
technicolor production model, the leptophobic Z' with width
\Gamma_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the
95% confidence level.


title: Leading Order QED Electrical Conductivity from the 3PI Effective Action

abstract:
  In this article we study the electrical conductivity in QED using the
resummed 3PI effective action. We work to 3-loop order in the effective action.
We show that the resulting expression for the conductivity is explicitly gauge
invariant, and that the integral equations that resum the pinching and colinear
contributions are produced naturally by the formalism. All leading order terms
are included, without the need for any kind of power counting arguments.


title:
The extremal volume ellipsoids of convex bodies, their symmetry
  properties, and their determination in some special cases

abstract:
  A convex body K has associated with it a unique circumscribed ellipsoid CE(K)
with minimum volume, and a unique inscribed ellipsoid IE(K) with maximum
volume. We first give a unified, modern exposition of the basic theory of these
extremal ellipsoids using the semi-infinite programming approach pioneered by
Fritz John in his seminal 1948 paper. We then investigate the automorphism
groups of convex bodies and their extremal ellipsoids. We show that if the
automorphism group of a convex body K is large enough, then it is possible to
determine the extremal ellipsoids CE(K) and IE(K) exactly, using either
semi-infinite programming or nonlinear programming. As examples, we compute the
extremal ellipsoids when the convex body K is the part of a given ellipsoid
between two parallel hyperplanes, and when K is a truncated second order cone
or an ellipsoidal cylinder.


title: Pion Production in Neutrino-Nucleon Reactions

abstract:
  We construct a model for the weak pion production off the nucleon, which in
addition to the weak excitation of the $\Delta(1232)$ resonance and its
subsequent decay into $N\pi$, it includes also some background terms required
by chiral symmetry. We re-fit the $C_5^A(q^2)$ form factor to the flux averaged
$\nu_\mu p \to \mu^-p\pi^+$ ANL $q^2-$differential cross section data, finding
a substantially smaller contribution of the $\Delta$ pole mechanism than
traditionally assumed in the literature. We also show that the interference
between the Delta pole and the background terms produces parity-violating
contributions to the pion angular differential cross section.


title:
One-dimensional resistive states in quasi-two-dimensional
  superconductors

abstract:
  We investigate competition between one- and two-dimensional topological
excitations - phase slips and vortices - in formation of resistive states in
quasi-two-dimensional superconductors in a wide temperature range below the
mean-field transition temperature $T_{C0}$. The widths $w$ = 100 nm of our
ultrathin NbN samples is substantially larger than the Ginzburg-Landau
coherence length $\xi$ = 4nm and the fluctuation resistivity above $T_{C0}$ has
a two-dimensional character. However, our data shows that the resistivity below
$T_{C0}$ is produced by one-dimensional excitations, - thermally activated
phase slip strips (PSSs) overlapping the sample cross-section. We also
determine the scaling phase diagram, which shows that even in wider samples the
PSS contribution dominates over vortices in a substantial region of
current/temperature variations. Measuring the resistivity within seven orders
of magnitude, we find that the quantum phase slips can only be essential below
this level.


title:
Combinatorically Prescribed Packings and Applications to Conformal and
  Quasiconformal Maps

abstract:
  The Andreev-Thurston Circle Packing Theorem is generalized to packings of
convex bodies in planar simply connected domains. This turns out to be a useful
tool for constructing conformal and quasiconformal mappings with interesting
geometric properties. We attempt to illustrate this with a few results about
uniformizations of finitely connected planar domains. For example, the
following variation of a theorem by Courant, Manel and Shiffman is proved and
generalized. If $G$ is an $n+1$-connected bounded planar domain, $H$ is a
simply connected bounded planar domain, and $P_1,P_2,...,P_n$ are (compact)
planar convex bodies, then sets $P_j'$ can be found so that $G$ is conformally
equivalent to $H-\cup_{j=1}^n P_j'$, and each $P_j'$ is either a point, or is
positively homothetic to $P_j$.


title:
Bayesian posterior classification of planetary nebulae according to the
  Peimbert types

abstract:
  In this paper we present a re-analysis of the criteria used to characterize
the Peimbert classes I, IIa, IIb, III and IV, through a statistical study of a
large sample of planetary nebulae previously classified according to these
groups. In the original classification, it is usual to find planetary nebulae
that cannot be associated with a single type; these most likely have dubious
classifications into two or three types. Statistical methods can greatly
contribute in providing a better characterization of planetary nebulae groups.
We use the Bayes Theorem to calculate the posterior probabilities for an object
to be member of each of the types I, IIa, IIb, III and IV. This calculation is
particularly important for planetary nebulae that are ambiguously classified in
the traditional method. The posterior probabilities are defined from the
probability density function of classificatory parameters of a well-defined
sample, composed only by planetary nebulae unambiguously fitted into the
Peimbert types. Because the probabilities depend on the available observational
data, they are conditional probabilities, and, as new observational data are
added to the sample, the classification of the nebula can be improved, to take
into account this new information. This method differs from the original
classificatory scheme, because it provides a quantitative result of the
representativity of the object within its group. Also, through the use of
marginal distributions it is possible to extend the Peimbert classification
even to those objects for which only a few classificatory parameters are known.


title: Invariant theory of abelian transvection groups

abstract:
  Let $G$ be a finite group acting linearly on the vector space $V$ over a
field of arbitrary characteristic. The action is called {\em coregular} if the
invariant ring is generated by algebraically independent homogeneous invariants
and the {\em direct summand property} holds if there is a surjective
$k[V]^G$-linear map $\pi:k[V]\to k[V]^G$. The following
Chevalley--Shephard--Todd type theorem is proved. Suppose $G$ is abelian, then
the action is coregular if and only if $G$ is generated by pseudo-reflections
and the direct summand property holds.


title:
The geometrically-averaged density of states calculated from the local
  Green's function as a measure of localization

abstract:
  With the goal of measuring localization in disordered interacting systems, we
examine the finite-size scaling of the geometrically-averaged density of states
calculated from the local Green's function with finite energy resolution. Our
results show that, unlike in a simple energy binning procedure, there is no
limit in which the finite energy resolution is irrelevant.


title: The permutation group S_N and large Nc excited baryons

abstract:
  We study the excited baryon states for an arbitrary number of colors Nc from
the perspective of the permutation group S_N of N objects. Classifying the
transformation properties of states and quark-quark interaction operators under
S_N allows a general analysis of the spin-flavor structure of the mass operator
of these states, in terms of a few unknown constants parameterizing the unknown
spatial structure. We explain how to perform the matching calculation of a
general two-body quark-quark interaction onto the operators of the 1/Nc
expansion. The inclusion of core and excited quark operators is shown to be
necessary. Considering the case of the negative parity L=1 states transforming
in the MS of S_N, we discuss the matching of the one-gluon and the
Goldstone-boson exchange interactions.


title: On Chevalley-Shephard-Todd's theorem in positive characteristic

abstract:
  Let $G$ be a finite group acting linearly on the vector space $V$ over a
field of arbitrary characteristic. The action is called coregular if the
invariant ring is generated by algebraically independent homogeneous invariants
and the direct summand property holds if there is a surjective $k[V]^G$-linear
map $\pi:k[V]\to k[V]^G$. The following Chevalley-Shephard-Todd type theorem is
proved. Suppose $V$ is an irreducible $kG$-representation, then the action is
coregular if and only if $G$ is generated by pseudo-reflections and the direct
summand property holds.


title: Maximum Entanglement in Squeezed Boson and Fermion States

abstract:
  A class of squeezed boson and fermion states is studied with particular
emphasis on the nature of entanglement. We first investigate the case of
bosons, considering two-mode squeezed states. Then we construct the fermion
version to show that such states are maximum entangled, for both bosons and
fermions. To achieve these results, we demonstrate some relations involving
squeezed boson states. The generalization to the case of fermions is made by
using Grassmann variables.


title: Representation functions of bases for binary linear forms

abstract:
  Let F(x_1,...,x_m) = u_1 x_1 + ... + u_m x_m be a linear form with nonzero,
relatively prime integer coefficients u_1,..., u_m. For any set A of integers,
let F(A) = {F(a_1,...,a_m) : a_i in A for i=1,...,m}. The representation
function associated with the form F is
  R_{A,F}(n) = card {(a_1,...,a_m) in A^m: F(a_1,..., a_m) = n}. The set A is a
basis with respect to F for almost all integers the set Z\F(A) has asymptotic
density zero. Equivalently, the representation function of an asymptotic basis
is a function f:Z -> N_0 U {\infty} such that f^{-1}(0) has density zero. Given
such a function, the inverse problem for bases is to construct a set A whose
representation function is f. In this paper the inverse problem is solved for
binary linear forms.


title:
Evidence for a finite temperature phase transition in a bilayer quantum
  Hall system

abstract:
  We study the Josephson-like interlayer tunneling signature of the strongly
correlated $\nu_T = 1$ quantum Hall phase in bilayer two-dimensional electron
systems as a function of the layer separation, temperature and interlayer
charge imbalance. Our results offer strong evidence that a finite temperature
phase transition separates the interlayer coherent phase from incoherent phases
which lack strong interlayer correlations. The transition temperature is
dependent on both the layer spacing and charge imbalance between the layers.


title:
Estimation of Possible Selectivity and Sensitivity of a Cooperative
  System to Low-Intensive Microwave Radiation

abstract:
  Recently, origins of non-deterministic behavior and free will in living
systems obtain growing interest (see, e.g. Maye A, Hsieh C, Sugihara G, Brembs
B (2007) Order in Spontaneous Behavior. PLoS ONE 2(5): e443.
doi:10.1371/journal.pone.0000443). In this text, devoted to electromagnetic
hypersensitivity, in n.2 and n.4, a possible physical mechanism of free will
and consequent indeterminacy in behavior is discussed.


title: On knot Floer width and Turaev genus

abstract:
  To each knot $K\subset S^3$ one can associated its knot Floer homology
$\hat{HFK}(K)$, a finitely generated bigraded abelian group. In general, the
nonzero ranks of these homology groups lie on a finite number of slope one
lines with respect to the bigrading. The width of the homology is, in essence,
the largest horizontal distance between two such lines. Also, for each diagram
$D$ of $K$ there is an associated Turaev surface, and the Turaev genus is the
minimum genus of all Turaev surfaces for $K$. We show that the width of knot
Floer homology is bounded by Turaev genus plus one. Skein relations for genus
of the Turaev surface and width of a complex that generates knot Floer homology
are given.


title: A remark on degenerate singularity in three dimensional Ricci flow

abstract:
  We show that a rescale limit at any degenerate singularity of Ricci flow in
dimension 3 is a steady gradient soliton. In particular, we give a geometric
description of type I and type II singularities.


title: Lattice Formulation of the N=4 D=3 Twisted Super Yang-Mills

abstract:
  A lattice formulation of a three dimensional super Yang-Mills model with a
twisted N=4 supersymmetry is proposed. The extended supersymmetry algebra of
all eight supercharges is fully and exactly realized on the lattice with a
modified "Leibniz rule". The formulation we employ here is a three dimensional
extension of the manifestly gauge covariant method which was developed in our
previous proposal of Dirac-K\"ahler twisted N=2 super Yang-Mills on a two
dimensional lattice. The twisted N=4 supersymmetry algebra is geometrically
realized on a three dimensional lattice with link supercharges and the use of
"shifted" (anti-)commutators. A possible solution to the recent critiques on
the link formulation will be discussed.


title:
Viscous regularization and r-adaptive remeshing for finite element
  analysis of lipid membrane mechanics

abstract:
  As two-dimensional fluid shells, lipid bilayer membranes resist bending and
stretching but are unable to sustain shear stresses. This property gives
membranes the ability to adopt dramatic shape changes. In this paper, a finite
element model is developed to study static equilibrium mechanics of membranes.
In particular, a viscous regularization method is proposed to stabilize
tangential mesh deformations and improve the convergence rate of nonlinear
solvers. The Augmented Lagrangian method is used to enforce global constraints
on area and volume during membrane deformations. As a validation of the method,
equilibrium shapes for a shape-phase diagram of lipid bilayer vesicle are
calculated. These numerical techniques are also shown to be useful for
simulations of three-dimensional large-deformation problems: the formation of
tethers (long tube-like exetensions); and Ginzburg-Landau phase separation of a
two-lipid-component vesicle. To deal with the large mesh distortions of the
two-phase model, modification of vicous regularization is explored to achieve
r-adaptive mesh optimization.


title:
From Time-symmetric Microscopic Dynamics to Time-asymmetric Macroscopic
  Behavior: An Overview

abstract:
  Time-asymmetric behavior as embodied in the second law of thermodynamics is
observed in {\it individual macroscopic} systems. It can be understood as
arising naturally from time-symmetric microscopic laws when account is taken of
a) the great disparity between microscopic and macroscopic scales, b) a low
entropy state of the early universe, and c) the fact that what we observe is
the behavior of systems coming from such an initial state--not all possible
systems. The explanation of the origin of the second law based on these
ingredients goes back to Maxwell, Thomson and particularly Boltzmann. Common
alternate explanations, such as those based on the ergodic or mixing properties
of probability distributions (ensembles) already present for chaotic dynamical
systems having only a few degrees of freedom or on the impossibility of having
a truly isolated system, are either unnecessary, misguided or misleading.
Specific features of macroscopic evolution, such as the diffusion equation, do
however depend on the dynamical instability (deterministic chaos) of
trajectories of isolated macroscopic systems.
  The extensions of these classical notions to the quantum world is in many
ways fairly direct. It does however also bring in some new problems. These will
be discussed but not resolved.


title: Theory of spin Hall effect

abstract:
  An extension of Drude model is proposed that accounts for spin and spin-orbit
interaction of charge carriers. Spin currents appear due to combined action of
the external electric field, crystal field and scattering of charge carriers.
The expression for spin Hall conductivity is derived for metals and
semiconductors that is independent of the scattering mechanism. In cubic
metals, spin Hall conductivity $\sigma_s$ and charge conductivity $\sigma_c$
are related through $\sigma_s = [2 \pi \hbar/(3mc^2)]\sigma_c^2$ with $m$ being
the bare electron mass. Theoretically computed value is in agreement with
experiment.


title: Inducing the Lovelock action

abstract:
  We re-analyze a possible ambiguity in the application of dimensional
regularization to Einstein-Gauss-Bonnet gravity, arising from the way one
treats the Gauss-Bonnet term. It is demonstrated that the addition of such a
term to the action gives rise to a non-minimal graviton wave operator, but does
not produce new on shell divergences at one loop order in d=4. However, from a
d-dimensional perspective the Gauss-Bonnet term is shown to generate new
divergences in the form of the six-dimensional Euler density. The conjecture
that one would next produce the eight-dimensional Euler term is shown to be
false.


title:
Probing the doping in metallic and semiconducting carbon nanotubes by
  Raman and transport measurements

abstract:
  In-situ Raman experiments together with transport measurements have been
carried out on carbon nanotubes as a function of gate voltage. In metallic
tubes, a large increase in the Raman frequency of the $G^-$ band, accompanied
by a substantial decrease of its line-width, is observed with electron or hole
doping. In addition, we see an increase in Raman frequency of the $G^+$ band in
semiconducting tubes. These results are quantitatively explained using
ab-initio calculations that take into account effects beyond the adiabatic
approximation. Our results imply that Raman spectroscopy can be used as an
accurate measure of the doping of both metallic and semiconducting nanotubes.


title: Coherent pion production in neutrino-nucleus collisions

abstract:
  We have investigated the neutrino induced coherent pion production reaction
at low and intermediate energies including pion, nucleon and Delta(1232)
resonance. Medium effects in the production mechanism and the distortion of the
pion wave function are included in the calculation. We find a strong reduction
of the cross section due to these effects and also substantial modifications in
the energy distributions of the final pion. The dependence on the atomic number
is discussed.


title:
Topological phases and topological entropy of two-dimensional systems
  with finite correlation length

abstract:
  We elucidate the topological features of the entanglement entropy of a region
in two dimensional quantum systems in a topological phase with a finite
correlation length $\xi$. Firstly, we suggest that simpler reduced quantities,
related to the von Neumann entropy, could be defined to compute the topological
entropy. We use our methods to compute the entanglement entropy for the ground
state wave function of a quantum eight-vertex model in its topological phase,
and show that a finite correlation length adds corrections of the same order as
the topological entropy which come from sharp features of the boundary of the
region under study. We also calculate the topological entropy for the ground
state of the quantum dimer model on a triangular lattice by using a mapping to
a loop model. The topological entropy of the state is determined by loop
configurations with a non-trivial winding number around the region under study.
Finally, we consider extensions of the Kitaev wave function, which incorporate
the effects of electric and magnetic charge fluctuations, and use it to
investigate the stability of the topological phase by calculating the
topological entropy.


title:
The Star Formation and Extinction Co-Evolution of UV-Selected Galaxies
  over 0.05<z<1.2

abstract:
  We use a new stacking technique to obtain mean mid IR and far IR to far UV
flux ratios over the rest near-UV/near-IR color-magnitude diagram. We employ
COMBO-17 redshifts and COMBO-17 optical, GALEX far and near UV, Spitzer IRAC
and MIPS Mid IR photometry. This technique permits us to probe infrared excess
(IRX), the ratio of far IR to far UV luminosity, and specific star formation
rate (SSFR) and their co-evolution over two orders of magnitude of stellar mass
and redshift 0.1<z<1.2. We find that the SSFR and the characteristic mass (M_0)
above which the SSFR drops increase with redshift (downsizing). At any given
epoch, IRX is an increasing function of mass up to M_0. Above this mass IRX
falls, suggesting gas exhaustion. In a given mass bin below M_0 IRX increases
with time in a fashion consistent with enrichment. We interpret these trends
using a simple model with a Schmidt-Kennicutt law and extinction that tracks
gas density and enrichment. We find that the average IRX and SSFR follows a
galaxy age parameter which is determined mainly by the galaxy mass and time
since formation. We conclude that blue sequence galaxies have properties which
show simple, systematic trends with mass and time such as the steady build-up
of heavy elements in the interstellar media of evolving galaxies and the
exhaustion of gas in galaxies that are evolving off the blue sequence. The IRX
represents a tool for selecting galaxies at various stages of evolution.


title: The Geometric Phase in Supersymmetric Quantum Mechanics

abstract:
  We explore the geometric phase in N=(2,2) supersymmetric quantum mechanics.
The Witten index ensures the existence of degenerate ground states, resulting
in a non-Abelian Berry connection. We exhibit a non-renormalization theorem
which prohibits the connection from receiving perturbative corrections.
However, we show that it does receive corrections from BPS instantons. We
compute the one-instanton contribution to the Berry connection for the massive
CP^1 sigma-model as the potential is varied. This system has two ground states
and the associated Berry connection is the smooth SU(2) 't Hooft-Polyakov
monopole.


title: Exact solution to the averaging problem in cosmology

abstract:
  The exact solution of a two-scale Buchert average of the Einstein equations
is derived for an inhomogeneous universe which represents a close approximation
to the observed universe. The two scales represent voids, and the bubble walls
surrounding them within which clusters of galaxies are located. As described
elsewhere [gr-qc/0702082], apparent cosmic acceleration can be recognised as a
consequence of quasilocal gravitational energy gradients between observers in
bound systems and the volume average position in freely expanding space. With
this interpretation, the new solution presented here replaces the Friedmann
solutions, in representing the average evolution of a matter-dominated universe
without exotic dark energy, while being observationally viable.


title:
Discovery of the Narrow-Line Seyfert 1 galaxy Mkn 335 in an historical
  low X-ray flux state

abstract:
  We report the discovery of the Narrow-Line Seyfert 1 galaxy Mkn 335 in an
extremely low X-ray state. A comparison of Swift observations obtained in May
and June/July 2007 with all previous X-ray observations between 1971 to 2006
show the AGN to have diminished in flux by a factor of more than 30, the lowest
X-ray flux Mkn 335 has ever been observed in. The Swift observations show an
extremely hard X-ray spectrum at energies above 2 keV. Possible interpretations
include partial covering absorption or X-ray reflection from the disk. In this
letter we consider the partial covering interpretation. The Swift observations
can be well fit by a strong partial covering absorber with varying absorption
column density N_H= 1-4 x 10^{23} cm-2 and a covering fraction f_c=0.9 - 1.
When corrected for intrinsic absorption, the X-ray flux of Mkn 335 varies by
only factors of 4-6. In the UV Mkn 335 shows variability in the order of 0.2
mag. We discuss the similarity of Mkn 335 with the highly variable NLS1
WPVS007, and speculate about a possible link between NLS1 galaxies and
broad-absorption line quasars.


title:
Predictions for the Cosmogenic Neutrino Flux in Light of New Data from
  the Pierre Auger Observatory

abstract:
  The Pierre Auger Observatory (PAO) has measured the spectrum and composition
of the ultrahigh energy cosmic rays with unprecedented precision. We use these
measurements to constrain their spectrum and composition as injected from their
sources and, in turn, use these results to estimate the spectrum of cosmogenic
neutrinos generated in their propagation through intergalactic space. We find
that the PAO measurements can be well fit if the injected cosmic rays consist
entirely of nuclei with masses in the intermediate (C, N, O) to heavy (Fe, Si)
range. A mixture of protons and heavier species is also acceptable but (on the
basis of existing hadronic interaction models) injection of pure light nuclei
(p, He) results in unacceptable fits to the new elongation rate data. The
expected spectrum of cosmogenic neutrinos can vary considerably, depending on
the precise spectrum and chemical composition injected from the cosmic ray
sources. In the models where heavy nuclei dominate the cosmic ray spectrum and
few dissociated protons exceed GZK energies, the cosmogenic neutrino flux can
be suppressed by up to two orders of magnitude relative to the all-proton
prediction, making its detection beyond the reach of current and planned
neutrino telescopes. Other models consistent with the data, however, are
proton-dominated with only a small (1-10%) admixture of heavy nuclei and
predict an associated cosmogenic flux within the reach of upcoming experiments.
Thus a detection or non-detection of cosmogenic neutrinos can assist in
discriminating between these possibilities.


title: Magnetogenesis from Rotating Cosmic String Loops

abstract:
  We present a mechanism to create vortices in a plasma via gravitational
dragging behind rotating cosmic string loops. The vortical motions create
magnetic fields by means of the Harrison-Rees mechanism; the fields are further
enhanced through galactic collapse and dynamo amplification. Employing the
Velocity dependent One Scale model (VOS) for the string network and
incorporating loop dynamics, we compute the magnetic fields generated around
the time of decoupling: these are just strong and coherent enough to account
for presently observed magnetic fields in spiral galaxies if efficient dynamos
with $\Gamma_{dy}^{-1}\approx 0.3$ Gyr are present.


title:
On the Emergence of Unstable Modes in an Expanding Domain for
  Energy-Conserving Wave Equations

abstract:
  Motivated by recent work on instabilities in expanding domains in
reaction-diffusion settings, we propose an analog of such mechanisms in
energy-conserving wave equations. In particular, we consider a nonlinear
Schr{\"o}dinger equation in a finite domain and show how the expansion or
contraction of the domain, under appropriate conditions, can destabilize its
originally stable solutions through the modulational instability mechanism.
Using both real and Fourier spacediagnostics, we monitor and control the
crossing of the instability threshold and, hence, the activation of the
instability. We also consider how the manifestation of this mechanism is
modified in a spatially inhomogeneous setting, namely in the presence of an
external parabolic potential, which is relevant to trapped Bose-Einstein
condensates.


title:
On the existence of tight contact structures on Seifert fibered
  3-manifolds

abstract:
  We determine the closed, oriented Seifert fibered 3-manifolds which carry
positive tight contact structures. Our main tool is a new non-vanishing
criterion for the contact Ozsvath-Szabo invariant.


title: A quantum characterization of NP

abstract:
  In this article we introduce a new complexity class called PQMA_log(2).
Informally, this is the class of languages for which membership has a
logarithmic-size quantum proof with perfect completeness and soundness which is
polynomially close to 1 in a context where the verifier is provided a proof
with two unentangled parts. We then show that PQMA_log(2) = NP. For this to be
possible, it is important, when defining the class, not to give too much power
to the verifier. This result, when compared to the fact that QMA_log = BQP,
gives us new insight on the power of quantum information and the impact of
entanglement.


title:
Reply to Comment on the paper ``Energy Loss of Charm Quarks in the
  Quark-Gluon Plasma: Collisional vs Radiative'' by Mishra et al

abstract:
  The comments raised in Ref. [1] by Mishra et al aim at two papers contained
in Ref. [2]. We show that those comments on Ref. [2] pointed out by Mishra et
al in Ref.[1] are not relevant and the concept used in Ref.[2] is consistent
and in compliance with the classical approximation of the transport
coefficients [3]. We would also like to note that most of the comments in Ref.
[1] were meant for light quarks, but are not even appropriate for heavy quarks.


title:
High-temperature behaviour of the helium-like K ALPHA G ratio: the
  effect of improved recombination rate coefficients for calcium, iron, and
  nickel

abstract:
  It is shown that above the temperature of maximum abundance, recombination
rates into the excited states of He-like ions that are calculated using
earlier, more approximate methods differ markedly from rates obtained from
recent distorted-wave and R-Matrix calculations (unified recombination rate
coefficients) for Ca, Fe, and Ni. The present rates lead to G ratios that are
greatly lower than those resulting from the more approximate rates in previous
works, by up to a factor of six at high electron temperatures. Excellent
agreement between the distorted-wave and the R-Matrix rates, as well as
excellent agreement in the G ratios calculated from them, provides support for
the accuracy of these new values which have a broad applicability to the
modelling and interpreting of X-ray spectra from a variety of astrophysical and
laboratory sources.


title:
Galois extensions and subspaces of bilinear forms with special rank
  properties

abstract:
  Let K be a field admitting a cyclic Galois extension of degree n. The main
result of this paper is a decomposition theorem for the space of alternating
bilinear forms defined on a vector space of odd dimension n over K. We show
that this space of forms is the direct sum of (n-1)/2 subspaces, each of
dimension n, and the non-zero elements in each subspace have constant rank
defined in terms of the orders of the Galois automorphisms. Furthermore, if
ordered correctly, for each integer k lying between 1 and (n-1)/2, the rank of
any non-zero element in the sum of the first k subspaces is at most n-2k+1.
Slightly less sharp similar results hold for cyclic extensions of even degree.


title: Suppression of elliptic flow in a minimally viscous quark-gluon plasma

abstract:
  We compute the time evolution of elliptic flow in non-central relativistic
heavy-ion collisions, using a (2+1)-dimensional code with longitudinal
boost-invariance to simulate viscous fluid dynamics in the causal
Israel-Stewart formulation. We show that even ``minimal'' shear viscosity
eta/s=hbar/(4pi) leads to a large reduction of elliptic flow compared to ideal
fluid dynamics, raising questions about the interpretation of recent
experimental data from the Relativistic Heavy Ion Collider.


title:
Semitransitive and transitive subsemigroups of the inverse symmetric
  semigroups

abstract:
  We classify minimal transitive subsemigroups of the finitary inverse
symmetric semigroup modulo the classification of minimal transitive subgroups
of finite symmetric groups; and semitransitive subsemigroups of the finite
inverse symmetric semigroup of the minimal cardinality modulo the
classification of transitive subgroups of the minimal cardinality of finite
symmetric groups.


title: The High Voltage Feedthroughs for the ATLAS Liquid Argon Calorimeters

abstract:
  The purpose, design specifications, construction techniques, and testing
methods are described for the high voltage feedthrough ports and filters of the
ATLAS Liquid Argon calorimeters. These feedthroughs carry about 5000 high
voltage wires from a room-temperature environment (300 K) through the cryostat
walls to the calorimeters cells (89 K) while maintaining the electrical and
cryogenic integrity of the system. The feedthrough wiring and filters operate
at a maximum high voltage of 2.5 kV without danger of degradation by corona
discharges or radiation at the Large Hadron Collider.


title:
Comment on 'Discreteness Effects in Simulations of Hot/Warm Dark Matter'
  by J. Wang & S.D.M. White

abstract:
  Wang and White (2007) have discussed some problems with N-body simulation
methods. These problems are a special case of a more general problem which has
been largely unacknowledged for approximately 25 years, and affects results of
all dark matter simulations on small scales (the definition of 'small' varying
with time). Extensive numerical experiments with multiple types of N-body codes
have demonstrated that spurious fluctuations due to particle discreteness grow
rapidly even in the presence of substantial small-scale power from the intended
model spectrum, and modify the results on scales smaller than the mean comoving
interparticle separation. This implies that the spatial resolution of such
simulations is typically limited not by the force softening length, often
referred to as the 'resolution', and not by the particle density in halos.
Instead it is approximately N^-1/3, where N is the mean particle density, and
of course depends on and improves very slowly with increased number of
particles. This calls into question many results on smaller scales over more
than two decades.


title: Geometric Complexity Theory: Introduction

abstract:
  These are lectures notes for the introductory graduate courses on geometric
complexity theory (GCT) in the computer science department, the university of
Chicago. Part I consists of the lecture notes for the course given by the first
author in the spring quarter, 2007. It gives introduction to the basic
structure of GCT. Part II consists of the lecture notes for the course given by
the second author in the spring quarter, 2003. It gives introduction to
invariant theory with a view towards GCT. No background in algebraic geometry
or representation theory is assumed. These lecture notes in conjunction with
the article \cite{GCTflip1}, which describes in detail the basic plan of GCT
based on the principle called the flip, should provide a high level picture of
GCT assuming familiarity with only basic notions of algebra, such as groups,
rings, fields etc.


title: On Lyubeznik numbers of projective schemes

abstract:
  Let $X$ be an arbitrary projective scheme over a field $k$. Let $A$ be the
local ring at the vertex of the affine cone for some embedding $\iota:
X\hookrightarrow \mathbb{P}^n_k$. G. Lyubeznik asked (in \cite{l2}) whether the
integers $\lambda_{i,j}(A)$ (defined in \cite{l1}), called the Lyubeznik
numbers of $A$, depend only on $X$, but not on the embedding. In this paper, we
make a big step toward a positive answer to this question by proving that in
positive characteristic, for a fixed $X$, the Lyubezink numbers
$\lambda_{i,j}(A)$ of the local ring $A$, can only achieve finitely many
possible values under all choices of embeddings.


title:
On P vs. NP, Geometric Complexity Theory, and the Flip I: a high level
  view

abstract:
  Geometric complexity theory (GCT) is an approach to the $P$ vs. $NP$ and
related problems through algebraic geometry and representation theory. This
article gives a high-level exposition of the basic plan of GCT based on the
principle, called the flip, without assuming any background in algebraic
geometry or representation theory.


title:
Geometric Complexity Theory VII: Nonstandard quantum group for the
  plethysm problem

abstract:
  This article describes a {\em nonstandard} quantum group that may be used to
derive a positive formula for the plethysm problem, just as the standard
(Drinfeld-Jimbo) quantum group can be used to derive the positive
Littlewood-Richardson rule for arbitrary complex semisimple Lie groups. The
sequel \cite{GCT8} gives conjecturally correct algorithms to construct
canonical bases of the coordinate rings of these nonstandard quantum groups and
canonical bases of the dually paired nonstandard deformations of the symmetric
group algebra. A positive $#P$-formula for the plethysm constant follows from
the conjectural properties of these canonical bases and the duality and
reciprocity conjectures herein.


title:
Reddening law and interstellar dust properties along Magellanic
  sight-lines

abstract:
  This study establishes that SMC, LMC and Milky Way extinction curves obey the
same extinction law which depends on the 2200A bump size and one parameter, and
generalizes the Cardelli, Clayton and Mathis (1989) relationship. This suggests
that extinction in all three galaxies is of the same nature. The role of linear
reddening laws over all the visible/UV wavelength range, particularly important
in the SMC but also present in the LMC and in the Milky Way, is also
highlighted and discussed.


title:
Geometric Complexity Theory VIII: On canonical bases for the nonstandard
  quantum groups

abstract:
  This article gives conjecturally correct algorithms to construct canonical
bases of the irreducible polynomial representations and the matrix coordinate
rings of the nonstandard quantum groups in GCT4 and GCT7, and canonical bases
of the dually paired nonstandard deformations of the symmetric group algebra
therein. These are generalizations of the canonical bases of the irreducible
polynomial representations and the matrix coordinate ring of the standard
quantum group, as constructed by Kashiwara and Lusztig, and the Kazhdan-Lusztig
basis of the Hecke algebra. A positive ($#P$-) formula for the well-known
plethysm constants follows from their conjectural properties and the duality
and reciprocity conjectures in \cite{GCT7}.


title:
Sky in Google Earth: The Next Frontier in Astronomical Data Discovery
  and Visualization

abstract:
  Astronomy began as a visual science, first through careful observations of
the sky using either an eyepiece or the naked eye, then on to the preservation
of those images with photographic media and finally the digital encoding of
that information via CCDs. This last step has enabled astronomy to move into a
fully automated era -- where data is recorded, analyzed and interpreted often
without any direct visual inspection. Sky in Google Earth completes that circle
by providing an intuitive visual interface to some of the largest astronomical
imaging surveys covering the full sky. By streaming imagery, catalogs, time
domain data, and ancillary information directly to a user, Sky can provide the
general public as well as professional and amateur astronomers alike with a
wealth of information for use in education and research. We provide here a
brief introduction to Sky in Google Earth, focusing on its extensible
environment, how it may be integrated into the research process and how it can
bring astronomical research to a broader community. With an open interface
available on Linux, Mac OS X and Windows, applications developed within Sky are
accessible not just within the Google framework but through any visual browser
that supports the Keyhole Markup Language. We present Sky as the embodiment of
a virtual telescope.


title: On the structure of the Si(103) surface

abstract:
  Although (103) is a stable nominal orientation for both silicon and
germanium, experimental observations revealed that in the case of silicon this
surface remains disordered on an atomic scale even after careful annealing. We
report here a set of low-energy reconstruction models corresponding to $1\times
2$, $2\times 2$, and $1\times 4$ periodicities, and propose that the observed
disorder stems from the presence of several coexisting reconstructions with
different morphologies and nearly equal surface energies. These models also
suggest that the model structures previously reported in the literature for the
(103) orientation have very high surface energies and are thus unlikely to be
experimentally observed.


title: Coherent Control of Trapped Bosons

abstract:
  We investigate the quantum behavior of a mesoscopic two-boson system produced
by number-squeezing ultracold gases of alkali metal atoms. The quantum Poincare
maps of the wavefunctions are affected by chaos in those regions of the phase
space where the classical dynamics produces features that are comparable to
hbar. We also investigate the possibility for quantum control in the dynamics
of excitations in these systems. Controlled excitations are mediated by pulsed
signals that cause Stimulated Raman Adiabatic passage (STIRAP) from the ground
state to a state of higher energy. The dynamics of this transition is affected
by chaos caused by the pulses in certain regions of the phase space. A
transition to chaos can thus provide a method of controlling STIRAP.


title: Perfect state transfer over distance-regular spin networks

abstract:
  By considering distance-regular graphs as spin networks, first we introduce
some particular spin Hamiltonians which are extended version of those of
Refs.\cite{8,9''}. Then, by using spectral analysis techniques and algebraic
combinatoric structure of distance-regular graphs such as stratification
introduced in \cite{obata, js} and Bose-Mesner algebra, we give a method for
finding a set of coupling constants in the Hamiltonians so that a particular
state initially encoded on one site of a network will evolve freely to the
opposite site without any dynamical controls, i.e., we show that how to derive
the parameters of the system so that perfect state transfer (PST) can be
achieved. As examples, the cycle networks with even number of vertices and
$d$-dimensional hypercube networks are considered in details and the method is
applied for some important distance-regular networks in appendix.


title:
Calculating effective resistances on underlying networks of association
  schemes

abstract:
  Recently, in Refs. \cite{jsj} and \cite{res2}, calculation of effective
resistances on distance-regular networks was investigated, where in the first
paper, the calculation was based on stratification and Stieltjes function
associated with the network, whereas in the latter one a recursive formula for
effective resistances was given based on the Christoffel-Darboux identity. In
this paper, evaluation of effective resistances on more general networks which
are underlying networks of association schemes is considered, where by using
the algebraic combinatoric structures of association schemes such as
stratification and Bose-Mesner algebras, an explicit formula for effective
resistances on these networks is given in terms of the parameters of
corresponding association schemes. Moreover, we show that for particular
underlying networks of association schemes with diameter $d$ such that the
adjacency matrix $A$ possesses $d+1$ distinct eigenvalues, all of the other
adjacency matrices $A_i$, $i\neq 0,1$ can be written as polynomials of $A$,
i.e., $A_i=P_i(A)$, where $P_i$ is not necessarily of degree $i$. Then, we use
this property for these particular networks and assume that all of the
conductances except for one of them, say $c\equiv c_1=1$, are zero to give a
procedure for evaluating effective resistances on these networks. The
preference of this procedure is that one can evaluate effective resistances by
using the structure of their Bose-Mesner algebra without any need to know the
spectrum of the adjacency matrices.


title: Morita equivalence of dual operator algebras

abstract:
  We consider a variant of the notion of Morita equivalence appropriate to
weak* closed algebras of Hilbert space operators, which we call {\em weak
Morita equivalence}. We obtain new variants, appropriate to the dual algebra
setting, of the basic theory of strong Morita equivalence, and new
nonselfadjoint variants of aspects of Rieffel's $W^*$-algebraic Morita
equivalence.


title: Simulation of an All-Silicon Tracker

abstract:
  We present recent improvements in the performance of the reconstruction of
non-prompt track in the SiD Detector Concept Design, including initial results
on the effect of longitudinal segmentation in the SiD tracker. We also describe
a generic tracking validation package developed at SCIPP.


title:
Optical Cluster-Finding with An Adaptive Matched-Filter Technique:
  Algorithm and Comparison with Simulations

abstract:
  We present a modified adaptive matched filter algorithm designed to identify
clusters of galaxies in wide-field imaging surveys such as the Sloan Digital
Sky Survey. The cluster-finding technique is fully adaptive to imaging surveys
with spectroscopic coverage, multicolor photometric redshifts, no redshift
information at all, and any combination of these within one survey. It works
with high efficiency in multi-band imaging surveys where photometric redshifts
can be estimated with well-understood error distributions. Tests of the
algorithm on realistic mock SDSS catalogs suggest that the detected sample is
~85% complete and over 90% pure for clusters with masses above 1.0*10^{14}
h^{-1} M_solar and redshifts up to z=0.45. The errors of estimated cluster
redshifts from maximum likelihood method are shown to be small (typically less
that 0.01) over the whole redshift range with photometric redshift errors
typical of those found in the Sloan survey. Inside the spherical radius
corresponding to a galaxy overdensity of Delta=200, we find the derived cluster
richness Lambda_{200} a roughly linear indicator of its virial mass M_{200},
which well recovers the relation between total luminosity and cluster mass of
the input simulation.


title:
Quantum electron transport in toroidal carbon nanotubes with metallic
  leads

abstract:
  A recursive Green's function method is employed to calculate the
density-of-states, transmission function, and current through a 150 layer (3,3)
armchair nanotorus (1800 atoms) with laterally attached metallic leads as
functions of relative lead angle and magnetic flux. Plateaus in the
transmissivity through the torus occur over wide ranges of lead placement,
accompanied by enhancements in the transmissivity through the torus as magnetic
flux normal to the toroidal plane is varied.


title: The coupling between pulsation and mass loss in massive stars

abstract:
  To what extent can pulsational instabilities resolve the mass-loss problem of
massive stars? How important is pulsation in structuring and modulating the
winds of these stars? What role does pulsation play in redistributing angular
momentum in massive stars? Although I cannot offer answers to these questions,
I hope at the very least to explain how they come to be asked.


title:
Regularizations of the Euler product representation for zeta functions
  and the Birch--Swinnerton-Dyer conjecture

abstract:
  We consider a variant expression to regularize the Euler product
representation of the zeta functions, where we mainly apply to that of the
Riemann zeta function in this paper. The regularization itself is identical to
that of the zeta function of the summation expression, but the non-use of the
M\"oebius function enable us to confirm a finite behavior of residual terms
which means an absence of zeros except for the critical line. Same technique
can be applied to the $L$-function associated to the elliptic curve, and we can
deal with the Taylor expansion at the pole in critical strip which is deeply
related to the Birch--Swinnerton-Dyer conjecture.


title:
U(1)' solution to the mu-problem and the proton decay problem in
  supersymmetry without R-parity

abstract:
  The Minimal Supersymmetric Standard Model (MSSM) is plagued by two major
fine-tuning problems: the mu-problem and the proton decay problem. We present a
simultaneous solution to both problems within the framework of a U(1)'-extended
MSSM (UMSSM), without requiring R-parity conservation. We identify several
classes of phenomenologically viable models and provide specific examples of
U(1)' charge assignments. Our models generically contain either lepton number
violating or baryon number violating renormalizable interactions, whose
coexistence is nevertheless automatically forbidden by the new U(1)' gauge
symmetry. The U(1)' symmetry also prohibits the potentially dangerous and often
ignored higher-dimensional proton decay operators such as QQQL and UUDE which
are still allowed by R-parity. Thus, under minimal assumptions, we show that
once the mu-problem is solved, the proton is sufficiently stable, even in the
presence of a minimum set of exotics fields, as required for anomaly
cancellation. Our models provide impetus for pursuing the collider
phenomenology of R-parity violation within the UMSSM framework.


title:
On the ruin time distribution for a Sparre Andersen process with
  exponential claim sizes

abstract:
  We derive a closed-form (infinite series) representation for the distribution
of the ruin time for the Sparre Andersen model with exponentially distributed
claims. This extends a recent result of Dickson et al. (2005) for such
processes with Erlang inter-claim times. We illustrate our result in the cases
of gamma and mixed exponential inter-claim time distributions.


title: Leptonic color models from Z_8 orbifolded AdS/CFT

abstract:
  We study orbifold compactifications of the type IIB superstring on AdS_5 x
S^5/Gamma, where Gamma is the abelian group Z_8, which can lead to non-SUSY
three and four family models based on quartification. In particular, we focus
on two models, one fully quartified model and one a model with two
trinification families and one quartification family, which reduces to the
standard model with a minimal leptonic color sector.


title:
Search for Gravitational Waves Associated with 39 Gamma-Ray Bursts Using
  Data from the Second, Third, and Fourth LIGO Runs

abstract:
  We present the results of a search for short-duration gravitational-wave
bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray
satellite experiments during LIGO's S2, S3, and S4 science runs. The search
involves calculating the crosscorrelation between two interferometer data
streams surrounding the GRB trigger time. We search for associated
gravitational radiation from single GRBs, and also apply statistical tests to
search for a gravitational-wave signature associated with the whole sample. For
the sample examined, we find no evidence for the association of gravitational
radiation with GRBs, either on a single-GRB basis or on a statistical basis.
Simulating gravitational-wave bursts with sine-gaussian waveforms, we set upper
limits on the root-sum-square of the gravitational-wave strain amplitude of
such waveforms at the times of the GRB triggers. We also demonstrate how a
sample of several GRBs can be used collectively to set constraints on
population models. The small number of GRBs and the significant change in
sensitivity of the detectors over the three runs, however, limits the
usefulness of a population study for the S2, S3, and S4 runs. Finally, we
discuss prospects for the search sensitivity for the ongoing S5 run, and beyond
for the next generation of detectors.


title:
Exact Foldy-Wouthuysen transformation for gravitational waves and
  magnetic field background

abstract:
  We consider an exact Foldy-Wouthuysen transformation for the Dirac spinor
field on the combined background of a gravitational wave and constant uniform
magnetic field. By taking the classical limit of the spinor field Hamiltonian
we arrive at the equations of motion for the non-relativistic spinning
particle. Two different kinds of the gravitational fields are considered and in
both cases the effect of the gravitational wave on the spinor field and on the
corresponding spinning particle may be enforced by the sufficiently strong
magnetic field. This result can be relevant for the astrophysical applications
and, in principle, useful for creating the gravitational wave detectors based
on atomic physics and precise interferometry.


title: Muon Identification without Iron

abstract:
  Muons can be identified with high efficiency and purity and reconstructed
with high precision is a detector with a dual readout calorimeter and a dual
solenoid to return the flux without iron. We shown CERN test beam data for the
calorimeter and calculations for the magnetic fields and the track
reconstruction. For isolated tracks, the rejection of pions against muons
ranges from $10^3$ at 20 GeV/c to $10^5$ at 300 GeV/c.


title:
Strain Hardening of Polymer Glasses: Entanglements, Energetics, and
  Plasticity

abstract:
  Simulations are used to examine the microscopic origins of strain hardening
in polymer glasses. While stress-strain curves for a wide range of temperature
can be fit to the functional form predicted by entropic network models, many
other results are fundamentally inconsistent with the physical picture
underlying these models. Stresses are too large to be entropic and have the
wrong trend with temperature. The most dramatic hardening at large strains
reflects increases in energy as chains are pulled taut between entanglements
rather than a change in entropy. A weak entropic stress is only observed in
shape recovery of deformed samples when heated above the glass transition.
While short chains do not form an entangled network, they exhibit partial shape
recovery, orientation, and strain hardening. Stresses for all chain lengths
collapse when plotted against a microscopic measure of chain stretching rather
than the macroscopic stretch. The thermal contribution to the stress is
directly proportional to the rate of plasticity as measured by breaking and
reforming of interchain bonds. These observations suggest that the correct
microscopic theory of strain hardening should be based on glassy state physics
rather than rubber elasticity.


title:
General K=-1 Friedman-Lema\^itre models and the averaging problem in
  cosmology

abstract:
  We introduce the notion of general K=-1 Friedman-Lema\^itre (compact)
cosmologies and the notion of averaged evolution by means of an averaging map.
We then analyze the Friedman-Lema\^itre equations and the role of gravitational
energy on the universe evolution. We distinguish two asymptotic behaviors:
radiative and mass gap. We discuss the averaging problem in cosmology for them
through precise definitions. We then describe in quantitative detail the
radiative case, stressing on precise estimations on the evolution of the
gravitational energy and its effect in the universe's deceleration. Also in the
radiative case we present a smoothing property which tells that the long time
H^{3} x H^{2} stability of the flat K=-1 FL models implies H^{i+1} x H^{i}
stability independently of how big the initial state was in H^{i+1} x H^{i},
i.e. there is long time smoothing of the space-time. Finally we discuss the
existence of initial "big-bang" states of large gravitational energy, showing
that there is no mathematical restriction to assume it to be low at the
beginning of time.


title:
Theory of light-induced current in molecular-tunneling junctions excited
  with intense shaped pulses

abstract:
  A theory for light-induced current by strong optical pulses in
molecular-tunneling junctions is described. We consider a molecular bridge
represented by its highest occupied and lowest unoccupied levels, HOMO and
LUMO, respectively. We take into account two types of couplings between the
molecule and the metal leads: electron transfer that gives rise to net current
in the biased junction and energy transfer between the molecule and
electron-hole excitations in the leads. Using a Markovian approximation, we
derive a closed system of equations for the expectation values of the relevant
variables: populations and molecular polarization that are binary, and exciton
populations that are tetradic in the annihilation and creation operators for
electrons in the molecular states. We have proposed an optical control method
using chirped pulses for enhancing charge transfer in unbiased junctions where
the bridging molecule is characterized by a strong charge-transfer transition.
An approximate analytical solution of the resulting dynamical equation is
supported by a full numerical solution. When energy transfer between the
molecule and electron-hole excitations in the leads is absent, the optical
control problem for inducing charge transfer with linearly chirped pulse can be
reduced to the Landau-Zener transition to a decaying level. When chirp is fast
with respect to the rate of the electron transfer, the Landau theory is
recovered. The proposed control mechanism is potentially useful for developing
novel opto-electronic single-electron devices with optical gating based on
molecular nanojunctions.


title:
Astrophysics Motivation behind the Pierre Auger Southern Observatory
  Enhancements

abstract:
  The Pierre Auger Collaboration intends to extend the energy range of its
southern observatory in Argentina for high quality data from 0.1 to 3 EeV. The
extensions, described in accompanying papers, include three additional
fluorescence telescopes with a more elevated field of view (HEAT) and a nested
surface array with 750 and 433 m spacing respectively and additional muon
detection capabilities (AMIGA). The enhancement of the detector will allow
measurement of cosmic rays, using the same techniques, from below the second
knee up to the highest energies observed. The evolution of the spectrum through
the second knee and ankle, and corresponding predicted changes in composition,
are crucial to the understanding of the end of Galactic confinement and the
effects of propagation on the lower energy portion of the extragalactic flux.
The latter is strongly related to the cosmological distribution of sources and
to the composition of the injected spectrum. We discuss the science motivation
behind these enhancements as well as the impact of combined HEAT and AMIGA
information on the assessment of shower simulations and reconstruction
techniques.


title:
Self-similar stable processes arising from high-density limits of
  occupation times of particle systems

abstract:
  We extend results on time-rescaled occupation time fluctuation limits of the
$(d,\alpha, \beta)$-branching particle system $(0<\alpha \leq 2, 0<\beta \leq
1)$ with Poisson initial condition. The earlier results in the homogeneous case
(i.e., with Lebesgue initial intensity measure) were obtained for dimensions
$d>\alpha / \beta$ only, since the particle system becomes locally extinct if
$d\le \alpha / \beta$. In this paper we show that by introducing high density
of the initial Poisson configuration, limits are obtained for all dimensions,
and they coincide with the previous ones if $d>\alpha/\beta$. We also give
high-density limits for the systems with finite intensity measures (without
high density no limits exist in this case due to extinction); the results are
different and harder to obtain due to the non-invariance of the measure for the
particle motion. In both cases, i.e., Lebesgue and finite intensity measures,
for low dimensions ($d<\alpha(1+\beta)/\beta$ and
$d<\alpha(2+\beta)/(1+\beta)$, respectively) the limits are determined by
non-L\'evy self-similar stable processes. For the corresponding high dimensions
the limits are qualitatively different: ${\cal S}'(R^d)$-valued L\'evy
processes in the Lebesgue case, stable processes constant in time on
$(0,\infty)$ in the finite measure case. For high dimensions, the laws of all
limit processes are expressed in terms of Riesz potentials. If $\beta=1$, the
limits are Gaussian. Limits are also given for particle systems without
branching, which yields in particular weighted fractional Brownian motions in
low dimensions. The results are obtained in the setup of weak convergence of
S'(R^d)$-valued processes.


title:
Entropy of (2+1)-dimensional de Sitter black hole to all orders in the
  Planck length

abstract:
  We calculate the statistical entropy of a scalar field on the background of
(2+1)-dimensional de Sitter space without an artificial cutoff considering
corrections to all orders in the Planck length from a generalized uncertainty
principle (GUP) on the quantum state density. The desired entropy proportional
to the horizon perimeter is obtained.


title: More Visible Effects of the Hidden Sector

abstract:
  There is a growing appreciation that hidden sector dynamics may affect the
supersymmetry breaking parameters in the visible sector (supersymmetric
standard model), especially when the dynamics is strong and superconformal. We
point out that there are effects that have not been previously discussed in the
literature. For example, the gaugino masses are suppressed relative to the
gravitino mass. We discuss their implications in the context of various
mediation mechanisms. The issues discussed include anomaly mediation with
singlets, the mu (B mu) problem in gauge and gaugino mediation, and distinct
mass spectra for the superparticles that have not been previously considered.


title: Born reciprocity and the 1/r potential

abstract:
  Many structures in nature are invariant under the transformation
(p,r)->(br,-p/b), where b is some scale factor. Born's reciprocity hypothesis
affirms that this invariance extends to the entire Hamiltonian and equations of
motion. We investigate this idea for atomic physics and galactic motion, where
one is basically dealing with a 1/r potential and the observations are very
accurate, so as to determine the scale $b = m\Omega$. We find that an $\Omega
\sim 1.5\times 10^{-15}$ Hz has essentially no effect on atomic physics but
might possibly offer an explanation for galactic rotation, without invoking
dark matter.


title:
Precise Numerical Evaluation of the Scalar One-Loop Integrals with the
  Infrared Divergence

abstract:
  We present a new approach for obtaining very precise integration results for
infrared vertex and box diagrams, where the integration is carried out directly
without performing any analytic integration of Feynman parameters. Using an
appropriate numerical integration routine with an extrapolation method,
together with a multi-precision library, we have obtained integration results
which agree with the analytic results to 10 digits even for such a very small
photon mass as $10^{-150}$ GeV in the infrared vertex diagram.


title: Modular co-evolution of metabolic networks

abstract:
  The architecture of biological networks has been reported to exhibit high
level of modularity, and to some extent, topological modules of networks
overlap with known functional modules. However, how the modular topology of the
molecular network affects the evolution of its member proteins remains unclear.
In this work, the functional and evolutionary modularity of Homo sapiens (H.
sapiens) metabolic network were investigated from a topological point of view.
Network decomposition shows that the metabolic network is organized in a highly
modular core-periphery way, in which the core modules are tightly linked
together and perform basic metabolism functions, whereas the periphery modules
only interact with few modules and accomplish relatively independent and
specialized functions. Moreover, over half of the modules exhibit
co-evolutionary feature and belong to specific evolutionary ages. Peripheral
modules tend to evolve more cohesively and faster than core modules do. The
correlation between functional, evolutionary and topological modularity
suggests that the evolutionary history and functional requirements of metabolic
systems have been imprinted in the architecture of metabolic networks. Such
systems level analysis could demonstrate how the evolution of genes may be
placed in a genome-scale network context, giving a novel perspective on
molecular evolution.


title: Low-frequency spectroscopy of superconducting photonic crystals

abstract:
  Transmission, reflection and absorption of electromagnetic radiation and
photon dispersion law for 2D photonic crystals with superconducting elements
are studied. The calculation of optical properties of photonic crystals is
studied by layer-by-layer Korringa-Kohn-Rostoker techniques. The results of
numerical calculations performed for an array of superconducting cylinders have
been understood in terms of a simple analytical model. The controlling of
optical properties of superconducting photonic crystal by temperature and
magnetic field is discussed. The variation of superconducting component density
with temperature leads, particularly, to significant reduction of the
transmission peaks and even to a nonmonotonous behavior of some absorbance
peaks.


title: Eigenvalues Estimates For The Dirac Operator In Terms Of Codazzi Tensors

abstract:
  We prove a lower bound for the first eigenvalue of the Dirac operator on a
compact Riemannian spin manifold depending on the scalar curvature as well as a
chosen Codazzi tensor. The inequality generalizes the classical estimate from
[2].


title:
Structure of logarithmically divergent one-loop lattice Feynman
  integrals

abstract:
  For logarithmically divergent one-loop lattice Feynman integrals I(p,a),
subject to mild general conditions, we prove the following expected and crucial
structural result: I(p,a) = f(p)log(aM)+g(p)+h(p,M) up to terms which vanish
for lattice spacing a -> 0. Here p denotes collectively the external momenta
and M is a mass scale which may be chosen arbitrarily. The f(p) and h(p,M) are
shown to be universal and coincide with analogous quantities in the
corresponding continuum integral when the latter is regularized either by
momentum cut-off or dimensional regularization. The non-universal term g(p) is
shown to be a homogeneous polynomial in p of the same degree as f(p). This
structure is essential for consistency between renormalized lattice and
continuum formulations of QCD at one loop.


title: Cluster-Spin Gaussian Model for Lattice-Ising Models

abstract:
  In this paper we lay special stress on analyzing the topological properties
of the lattice systems and try to ovoid the conventional ways to calculate the
critical points. Only those clusters with finite sizes can execute the self
similar transformations of infinite hierarchies. Each ordered cluster has
fractal dimension, their minimum relates to the edge fixed point, which accords
with the transformations fixed point relating to a critical point. There are
two classes of systems and clusters by their connectivity. Using mathematic
mapping method we set up cluster-spin Gaussian model solved accurately. There
are single state and -fold coupling state in a reducible cluster, each of which
corresponds to a subsystem described by a Gaussian model. By the minimal
fractal dimension a final expression of the critical points is obtained. The
critical points of three lattice systems are calculated, our method makes the
calculations very simplified and highly accurate. A possibility of existence of
different clusters at the critical temperature is discussed.


title:
Godel's theorem as a corollary of impossibility of complete
  axiomatization of geometry

abstract:
  Not any geometry can be axiomatized. The paradoxical Godel's theorem starts
from the supposition that any geometry can be axiomatized and goes to the
result, that not any geometry can be axiomatized. One considers example of two
close geometries (Riemannian geometry and $\sigma $-Riemannian one), which are
constructed by different methods and distinguish in some details. The
Riemannian geometry reminds such a geometry, which is only a part of the full
geometry. Such a possibility is covered by the Godel's theorem.


title: Connections between high energy QCD and statistical physics

abstract:
  It has been proposed that the energy evolution of QCD amplitudes in the
high-energy regime falls in the universality class of reaction-diffusion
processes. We review the arguments for this correspondence, and we explain how
it enables one to compute analytically asymptotic features of QCD amplitudes.


title: A description based on Schubert classes of cohomology of flag manifolds

abstract:
  We describe the integral cohomology rings of the flag manifolds of types B_n,
D_n, G_2 and F_4 in terms of their Schubert classes. The main tool is the
divided difference operators of Bernstein-Gelfand-Gelfand and Demazure. As an
application, we compute the Chow rings of the corresponding complex algebraic
groups, recovering thereby the results of R. Marlin.


title: Low accretion rates at the AGN cosmic downsizing epoch

abstract:
  Context: X-ray surveys of Active Galactic Nuclei (AGN) indicate `cosmic
downsizing', with the comoving number density of high-luminosity objects
peaking at higher redshifts (z about 2) than low-luminosity AGN (z<1). Aims: We
test whether downsizing is caused by activity shifting towards low-mass black
holes accreting at near-Eddington rates, or by a change in the average rate of
accretion onto supermassive black holes. We estimate the black hole masses and
Eddington ratios of an X-ray selected sample of AGN in the Chandra Deep Field
South at z<1, probing the epoch where AGN cosmic downsizing has been reported.
Methods: Black hole masses are estimated both from host galaxy stellar masses,
which are estimated from fitting to published optical and near-infrared
photometry, and from near-infrared luminosities, applying established
correlations between black hole mass and host galaxy properties. Both methods
give consistent results. Comparison and calibration of possible
redshift-dependent effects is also made using published faint host galaxy
velocity dispersion measurements. Results: The Eddington ratios in our sample
span the range 10^{-5} to 1, with median log(L_bol/L_Edd)=-2.87, and with
typical black hole masses about 10^{8} solar masses. The broad distribution of
Eddington ratios is consistent with that expected for AGN samples at low and
moderate luminosity. We find no evidence that the CDF-S AGN population is
dominated by low-mass black holes accreting at near-Eddington ratios and the
results suggest that diminishing accretion rates onto average-sized black holes
are responsible for the reported AGN downsizing at redshifts below unity.


title:
Sound Generation by a Turbulent Flow in Musical Instruments -
  Multiphysics Simulation Approach -

abstract:
  Total computational costs of scientific simulations are analyzed between
direct numerical simulations (DNS) and multiphysics simulations (MPS) for sound
generation in musical instruments. In order to produce acoustic sound by a
turbulent flow in a simple recorder-like instrument, compressible fluid dynamic
calculations with a low Mach number are required around the edges and the
resonator of the instrument in DNS, while incompressible fluid dynamic
calculations coupled with dynamics of sound propagation based on the
Lighthill's acoustic analogy are used in MPS. These strategies are evaluated
not only from the viewpoint of computational performances but also from the
theoretical points of view as tools for scientific simulations of complicated
systems.


title: Laplacian comparison for Alexandrov spaces

abstract:
  We consider an infinitesimal version of the Bishop-Gromov relative volume
comparison condition as generalized notion of Ricci curvature bounded below for
Alexandrov spaces. We prove a Laplacian comparison theorem for Alexandrov
spaces under the condition. As an application we prove a topological splitting
theorem.


title:
Structural peculiarities of plastically-deformed cementite and their
  influence on magnetic characteristics and Mossbauer parameters

abstract:
  Cementite Fe3C is studied with first-principles calculations. Two possible
positions of carbon atoms in the iron sublattice are considered: with prismatic
or octahedral environment. Mossbauer spectra (MS) with parameters calculated
for both modifications are simulated above and below the Curie temperature. A
possibility to detect the change in carbon position upon annealing from MS is
discussed. It is shown that this is hardly possible using a standard approach
to treatment of MS, but it can be seen in more subtle details of the MS below
the Curie temperature, such as widths and positions of separate lines.


title:
MarlinTPC: A Marlin based common TPC software framework for the LC-TPC
  collaboration

abstract:
  We describe the goals and present functionality of MarlinTPC, a common
software framework for the LC-TPC collaboration based on LCIO, Marlin and other
ilcsoft tools.


title: Magneto-optical behaviour of EuIn_2P_2

abstract:
  We report results of a magneto-optical investigation of the Zintl-phase
compound EuIn$_2$P$_2$. The compound orders magnetically at $T_C$=24 K and
exhibits concomitant large magnetoresistance effects. For $T\le$50 K and
increasing magnetic fields we observe a transfer of spectral weight in
$\sigma_1(\omega)$ from energies above 1 eV into the low-energy metallic
component as well as into a mid-infrared signal centered at about 600
cm$^{-1}$. This latter absorption is reminiscent to what has been seen in a
large variety of so-called Kondo materials and ascribed to excitations across
the hybridization gap. The observed gain of Drude weight upon increasing
magnetic field suggests an enhancement of the itinerant charge-carrier
concentration due to the increasing magnetization, a phenomenon that was
previously observed in other compounds which exhibit colossal magnetoresistive
effects.


title: Brownian dynamics of a microswimmer

abstract:
  We report on dynamic properties of a simple model microswimmer composed of
three spheres and propelling itself in a viscous fluid by spinning motion of
the spheres under zero net torque constraint. At a fixed temperature and
increasing the spinning frequency, the swimmer demonstrates a transition from
dissipation-dominated to a pumping-dominated motion regime characterized by
negative effective friction coefficient. In the limit of high frequencies, the
diffusion of the swimmer can be described by a model of an active particle with
constant velocity.


title: The formation and ordering of local magnetic moments in Fe-Al alloys

abstract:
  With density functional theory, studied are the local magnetic moments in
Fe-Al alloys depending on concentration and Fe nearest environment. At zero
temperature, the system can be in different states: ferromagnetic,
antiferromagnetic and spin-spiral waves (SSW) which has a minimum energy. Both
SSW and negative moment of Fe atoms with many Al atoms around them agree with
experiments. Magnetization curves taken from literature are analysed.
Assumption on percolation character of size distribution of magnetic clusters
describes well the experimental superparamagnetic behaviour above 150 K.


title: The thermal width of heavy quarkonia moving in quark gluon plasma

abstract:
  The velocity dependence of the thermal width of heavy quarkonia traveling
with respect to the quark gluon plasma is calculated up to the NLO in
perturbative QCD. At the LO, the width decreases with increasing speed, whereas
at the NLO it increases with a magnitude approximately proportional to the
expectation value of the relative velocity between the quarkonium and a parton
in thermal equilibrium. Such an asymptotic behavior is due to the NLO
dissociation cross section converging to a nonvanishing value in the high
energy limit.


title: Quasisymmetric structures on surfaces

abstract:
  We show that a locally Ahlfors 2-regular and locally linearly locally
contractible metric surface is locally quasisymmetrically equivalent to the
disk. We also discuss an application of this result to the problem of
characterizing surfaces in some Euclidean space that are locally bi-Lipschitz
equivalent to an open subset of the plane.


title: On frames in Hilbert modules over pro-C*-algebras

abstract:
  We introduce the concept of frame of multipliers in Hilbert modules over
pro-C*-algebras and show that many properties of frames in Hilbert C*-modules
are valid for frames of multipliers in Hilbert modules over pro-C*-algebras.


title: Copies of a one-ended group in a Mapping Class Group

abstract:
  We establish that, given $\Sigma$ a compact orientable surface, and $G$ a
finitely presented one-ended group, the set of copies of $G$ in the mapping
class group $\mathcal{MCG}(\Sigma)$ consisting of only pseudo-anosov elements
except identity, is finite up to conjugacy. This relies on a result of Bowditch
on the same problem for images of surfaces groups. He asked us whether we could
reduce the case of one-ended groups to his result ; this is a positive answer.
Our work involves analogues of Rips and Sela canonical cylinders in curve
complexes, and the argument of Delzant to bound the number of images of a
one-ended group in a hyperbolic group.


title:
Optimizing the electronic control loop of a solid-state ring laser
  gyroscope

abstract:
  We study in this Letter the dynamical effects of the limited bandwidth of the
control electronics in a solid-state (Nd-YAG) ring laser gyroscope. We derive a
stability condition for the rotation-sensing regime in the case of a
first-order control loop, showing that the smallest measurable rotation speed
depends directly on the cutoff frequency value. Our experimental measurements
are in good agreement with this prediction.


title:
Appropriate SCF basis sets for orbital studies of galaxies and a
  `quantum-mechanical' method to compute them

abstract:
  We address the question of an appropriate choice of basis functions for the
self-consistent field (SCF) method of simulation of the N-body problem. Our
criterion is based on a comparison of the orbits found in N-body realizations
of analytical potential-density models of triaxial galaxies, in which the
potential is fitted by the SCF method using a variety of basis sets, with those
of the original models. Our tests refer to maximally triaxial Dehnen
gamma-models for values of $\gamma$ in the range 0<=gamma<=1. When an N-body
realization of a model is fitted by the SCF method, the choice of radial basis
functions affects significantly the way the potential, forces, or derivatives
of the forces are reproduced, especially in the central regions of the system.
We find that this results in serious discrepancies in the relative amounts of
chaotic versus regular orbits, or in the distributions of the Lyapunov
characteristic exponents, as found by different basis sets. Numerical tests
include the Clutton-Brock and the Hernquist-Ostriker (HO) basis sets, as well
as a family of numerical basis sets which are `close' to the HO basis set. The
family of numerical basis sets is parametrized in terms of a quantity
$\epsilon$ which appears in the kernel functions of the Sturm-Liouville (SL)
equation defining each basis set. The HO basis set is the $\epsilon=0$ member
of the family. We demonstrate that grid solutions of the SL equation yielding
numerical basis sets introduce large errors in the variational equations of
motion. We propose a quantum-mechanical method of solution of the SL equation
which overcomes these errors. We finally give criteria for a choice of optimal
value of $\epsilon$ and calculate the latter as a function of the value of
gamma.


title: Elation generalised quadrangles of order (s,p), where p is prime

abstract:
  We show that an elation generalised quadrangle which has p+1 lines on each
point, for some prime p, is classical or arises from a flock of a quadratic
cone (i.e., is a flock quadrangle).


title: Lie admissible algebras are Volichenko

abstract: Withdrawn on account of a crucial error in the main theorem


title: Robust Preparation of GHZ and W States of Three Distant Atoms

abstract:
  Schemes to generate Greenberger-Horne-Zeilinger(GHZ) and W states of three
distant atoms are proposed in this paper. The schemes use the effects of
quantum statistics of indistinguishable photons emitted by the atoms inside
optical cavities. The advantages of the schemes are their robustness against
detection inefficiency and asynchronous emission of the photons. Moreover, in
Lamb-Dicke limit, the schemes do not require simultaneous click of the
detectors, this makes the schemes more realizable in experiments.


title:
On non-monotonic orbital velocity profiles around rapidly rotating
  Kerr-(anti)de Sitter black holes: acomment to the recently published results

abstract:
  Critical discussion of the recently published results [Muller, A. and
Aschenbach, B. 2007 Class. Quantum Grav. 24, p. 2637; arXiv:0704.3963] on the
non-monotonic orbital velocity profiles of the Keplerian motion of test
particles and l = const motion of test perfect fluid around K(a)dS black holes
is given, and the discrepancies concerned the existence of the non-monotonicity
in dependence of the spacetime parameters are corrected. Moreover a new
non-monotonic behaviour of the Keplerian orbital velocity in the Kerr-antide
Sitter spacetimes is highlighted.


title: Measurable entanglement for tripartite quantum pure states of qubits

abstract:
  We show that for tripartite quantum pure states of qubits, all the kinds of
entanglement in terms of SLOCC classification are experimentally measurable by
simple projective measurements, provided that four copies of the composite
quantum system are available. In particular, the entanglement of reduced
density matrices, even though they are mixed states, can be exactly determined
in experiment. Concurrence of assistance is also shown to be measurable by
introducing an interesting equations with explicit physical meanings.


title: Weak approximation of a fractional SDE

abstract:
  In this note, a diffusion approximation result is shown for stochastic
differential equations driven by a (Liouville) fractional Brownian motion B
with Hurst parameter H in (1/3,1/2). More precisely, we resort to the
Kac-Stroock type approximation using a Poisson process studied in Bardina,
Jolis and Tudor (2003) and Delgado and Jolis (2000), and our method of proof
relies on the algebraic integration theory introduced by Gubinelli (2004).


title:
The UV colours of high-redshift early-type galaxies: evidence for recent
  star formation and stellar mass assembly over the last 8 billion years

abstract:
  We combine deep UBVRIzJK photometry from the Multiwavelength Survey by
Yale-Chile (MUSYC) with redshifts from the COMBO-17 survey to perform a
large-scale study of the rest-frame ultraviolet (UV) properties of 674
high-redshift (0.5<z<1) early-type galaxies, drawn from the Extended Chandra
Deep Field South (E-CDFS). Galaxy morphologies are determined through visual
inspection of Hubble Space Telescope (HST) images taken from the GEMS survey.
We harness the sensitivity of the UV to young (<1 Gyr old) stars to quantify
the recent star formation history of early-type galaxies across a range of
luminosities (-23.5 < M(V) < -18). Comparisons to simple stellar populations
forming at high redshift indicate that only ~1.1 percent of early-types in this
sample are consistent with purely passive ageing since z=2. Parametrising the
recent star formation (RSF) in terms of the mass fraction of stars less than a
Gyr old, we find that the early-type population as a whole shows a typical RSF
between 5 and 13% in the redshift range 0.5<z<1. Early-types on the UV red
sequence show RSF values less than 5% while the reddest early-types are
virtually quiescent with RSF values of ~1%. We find compelling evidence that
early-types of all luminosities form stars over the lifetime of the Universe,
although the bulk of their star formation is already complete at high redshift.
This tail-end of star formation is measurable and not negligible, with luminous
(-23<M(V)<-20.5) early-types potentially forming 10-15% of their mass since
z=1, with their less luminous (M(V)>-20.5) counterparts potentially forming
30-60 percent of their mass in the same redshift range. (abridged)


title: A SIMBOL-X View of Microquasars

abstract:
  Based on spectral simulations, I show how focusing of the X-ray radiations
above 10 keV will open a new window for the study of microquasars. With
simulations of soft and hard state spectra of Galactic sources, I discuss how
SIMBOL-X can help to precisely measure the spin of black holes. Spectral study
on short ~1 s time scales will also allow the accretion-ejection connections to
be accessed, and the formation of jets possibly witnessed in X-rays. I then
turn to external galaxies, and demonstrate that spectral studies of hard
sources will be possible up to at least ~1 Mpc. For such sources, subtle
spectral signatures (e.g. a reflection bump) will clearly be detected. I
finally discuss the implications that these original results will bring on the
physics of microquasars and black holes.


title: Circular invasion of fluid into a quenched disordered media

abstract:
  The Hele-Shaw experiment is performed with a circular invasion to study the
scaling and dynamic behavior of the interface. We did not find any universal
power law. The time exponent varies with the range of scale, as has been
reported in the literature but not captured by existing models. We ascribe this
distinct difference from the planar injection to the fact that our interface
size grows with time. This renders the old geometries being constantly pushed
apart to leave rooms for new features. As a result, the amplitude of the
interface spectrum will decrease with the angular momentum, different from that
of a white noise commonly assumed for the planar injection. Due to the moving
boundary, the existing Kardar-Parisi-Zhang and Edwards-Wilkinson (EW) equations
can no longer be applied. We propose a modified EW equation that not only
conserves the fluid volume, but is also capable of predicting all the above
features. Two phenomenological coefficients are introduced to represent the
competing trend of instability and smoothness. Their dependence on the
microscopic parameters are determined from dimensional arguments, and their
estimated values conform with the experiments.


title:
Group velocity control in the ultraviolet domain via interacting
  dark-state resonances

abstract:
  The propagation of a weak probe field in a laser-driven four-level atomic
system is investigated. We choose mercury as our model system, where the probe
transition is in the ultraviolet region. A high-resolution peak appears in the
optical spectra due to the presence of interacting dark resonances. We show
that this narrow peak leads to superluminal light propagation with strong
absorption, and thus by itself is only of limited interest. But if in addition
a weak incoherent pump field is applied to the probe transition, then the peak
structure can be changed such that both sub- and superluminal light propagation
or a negative group velocity can be achieved without absorption, controlled by
the incoherent pumping strength.


title: A Comparative Study of Stochastic Volatility Models

abstract:
  The correlated stochastic volatility models constitute a natural extension of
the Black and Scholes-Merton framework: here the volatility is not a constant,
but a stochastic process correlated with the price log-return one. At present,
several stochastic volatility models are discussed in the literature, differing
in the dynamics attached to the volatility. The aim of the present work is to
compare the most recent results about three popular models: the Vasicek, Heston
and exponential Ornstein-Uhlenbeck models. We analyzed for each of them the
theoretical results known in the literature (volatility and return
distribution, higher-order moments and different-time correlations) in order to
test their predictive effectiveness on the outcomes of original numerical
simulations, paying particular attention to their ability to reproduce
empirical statistical properties of prices. The numerical results demonstrate
that these models can be implemented maintaining all their features, especially
in view of financial applications like market risk management or option
pricing. In order to critically compare the models, we also perform an
empirical analysis of financial time series from the Italian stock market,
showing the exponential Ornstein-Uhlenbeck model's ability to capture the
stylized facts of volatility and log-return probability distributions.


title: Survival of icy grains in debris discs. The role of photosputtering

abstract:
  We put theoretical constraints on the presence and survival of icy grains in
debris discs. Particular attention is paid to UV sputtering of water ice, which
has so far not been studied in detail in this context. We present a
photosputtering model based on available experimental and theoretical studies.
We quantitatively estimate the erosion rate of icy and ice-silicate grains,
under the influence of both sublimation and photosputtering, as a function of
grain size, composition and distance from the star. The effect of erosion on
the grain's location is investigated through numerical simulations coupling the
grain size to its dynamical evolution. Our model predicts that photodesorption
efficiently destroy ice in optically thin discs, even far beyond the
sublimation snow line. For the reference case of beta Pictoris, we find that
only > 5mm grains can keep their icy component for the age of the system in the
50-150AU region. When taking into account the collisional reprocessing of
grains, we show that the water ice survival on grains improves (grains down to
~ 20 um might be partially icy). However, estimates of the amount of gas
photosputtering would produce on such a hypothetical population of big icy
grains lead to values for the OI column density that strongly exceed
observational constraints for beta Pic, thus ruling out the presence of a
significant amount of icy grains in this system. Erosion rates and icy grains
survival timescales are also given for a set of 11 other debris disc systems.
We show that, with the possible exception of M stars, photosputtering cannot be
neglected in calculations of icy grain lifetimes.


title: Combinatorial aspects of boundary loop models

abstract:
  We discuss in this paper combinatorial aspects of boundary loop models, that
is models of self-avoiding loops on a strip where loops get different weights
depending on whether they touch the left, the right, both or no boundary. These
models are described algebraically by a generalization of the Temperley-Lieb
algebra, dubbed the two-boundary TL algebra. We give results for the dimensions
of TL representations and the corresponding degeneracies in the partition
functions. We interpret these results in terms of fusion and in the light of
the recently uncovered A_n large symmetry present in loop models, paving the
way for the analysis of the conformal field theory properties. Finally, we
propose conjectures for determinants of Gram matrices in all cases, including
the two-boundary one, which has recently been discussed by de Gier and Nichols.

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


title: The night-sky at the Calar Alto Observatory

abstract:
  We present a characterization of the main properties of the night-sky at the
  Calar Alto observatory for the time period between 2004 and 2007. We use
optical spectrophotometric data, photometric calibrated images taken in
moonless observing periods, together with the observing conditions regularly
monitored at the observatory, such as atmospheric extinction and seeing. We
derive, for the first time, the typical moonless night-sky optical spectrum for
the observatory. The spectrum shows a strong contamination by different
pollution lines, in particular from Mercury lines, which contribution to the
sky-brightness in the different bands is of the order of ~0.09 mag, ~0.16 mag
and ~0.10 mag in B, V and R respectively. The zenith-corrected values of the
moonless night-sky surface brightness are 22.39, 22.86, 22.01, 21.36 and 19.25
mag arcsec^-2 in U, B, V, R and I, which indicates that Calar Alto is a
particularly dark site for optical observations up to the I-band. The fraction
of astronomical useful nights at the observatory is ~70%, with a ~30% of
photometric nights. The typical extinction at the observatory is k_V~0.15 mag
in the Winter season, with little dispersion. In summer the extinction has a
wider range of values, although it does not reach the extreme peaks observed at
other sites. The median seeing for the last two years (2005-6) was ~0.90",
being smaller in the Summer (~0.87") than in the Winter (~0.96"). We conclude
in general that after 26 years of operations Calar Alto is still a good
astronomical site, being a natural candidate for future large aperture optical
telescopes.