title: On deconvolution with repeated measurements

abstract:
  In a large class of statistical inverse problems it is necessary to suppose
that the transformation that is inverted is known. Although, in many
applications, it is unrealistic to make this assumption, the problem is often
insoluble without it. However, if additional data are available, then it is
possible to estimate consistently the unknown error density. Data are seldom
available directly on the transformation, but repeated, or replicated,
measurements increasingly are becoming available. Such data consist of
``intrinsic'' values that are measured several times, with errors that are
generally independent. Working in this setting we treat the nonparametric
deconvolution problems of density estimation with observation errors, and
regression with errors in variables. We show that, even if the number of
repeated measurements is quite small, it is possible for modified kernel
estimators to achieve the same level of performance they would if the error
distribution were known. Indeed, density and regression estimators can be
constructed from replicated data so that they have the same first-order
properties as conventional estimators in the known-error case, without any
replication, but with sample size equal to the sum of the numbers of
replicates. Practical methods for constructing estimators with these properties
are suggested, involving empirical rules for smoothing-parameter choice.


title: Combined local implementation of nonlocal operations using GHZ states

abstract:
  We propose a protocol for local implementation of two consecutive nonlocal
operations by three parters. It consumes one shared GHZ state in this protocol.
We also demonstrate that these resources are sufficient and necessary to
locally implement two consecutive CNOT operations.


title: On the zeros of functions in the Selberg class

abstract:
  It is proved that under some suitable conditions, the degree two functions in
the Selberg class have infinitely many zeros on the critical line.


title: Bell-inequality violation with a triggered photon-pair source

abstract:
  Here we demonstrate, for the first time, violation of Bell's inequality using
a triggered quantum dot photon-pair source without post-selection. Furthermore,
the fidelity to the expected Bell state can be increased above 90% using
temporal gating to reject photons emitted at times when collection of
uncorrelated light is more probable. A direct measurement of a CHSH Bell
inequality is made showing a clear violation, highlighting that a quantum dot
entangled photon source is suitable for communication exploiting non-local
quantum correlations.


title:
Quark and lepton masses at the GUT scale including SUSY threshold
  corrections

abstract:
  We investigate the effect of supersymmetric (SUSY) threshold corrections on
the values of the running quark and charged lepton masses at the GUT scale
within the large $\tan\beta$ regime of the MSSM. In addition to the typically
dominant SUSY QCD contributions for the quarks, we also include the electroweak
contributions for quarks and leptons and show that they can have significant
effects. We provide the GUT scale ranges of quark and charged lepton Yukawa
couplings as well as of the ratios $m_\mu/m_s$, $m_e/m_d$, $y_\tau/y_b$ and
$y_t/y_b$ for three example ranges of SUSY parameters. We discuss how the
enlarged ranges due to threshold effects might open up new possibilities for
constructing GUT models of fermion masses and mixings.


title: Generalized parton distributions of the pion

abstract:
  Generalized Parton Distributions of the pion are evaluated in chiral quark
models with the help of double distributions. As a result the polynomiality
conditions are automatically satisfied. In addition, positivity constraints,
proper normalization and support, sum rules, and soft pion theorems are
fulfilled. We obtain explicit expressions holding at the low-energy quark-model
scale, which exhibit no factorization in the t-dependence. The crucial QCD
evolution of the quark-model distributions is carried out up to experimental or
lattice scales. The obtained results for the Parton Distribution Function and
the Parton Distribution Amplitude describe the available experimental and
lattice data, confirming that the quark-model scale is low, around 320 MeV.


title: Estimation of a semiparametric transformation model

abstract:
  This paper proposes consistent estimators for transformation parameters in
semiparametric models. The problem is to find the optimal transformation into
the space of models with a predetermined regression structure like additive or
multiplicative separability. We give results for the estimation of the
transformation when the rest of the model is estimated non- or
semi-parametrically and fulfills some consistency conditions. We propose two
methods for the estimation of the transformation parameter: maximizing a
profile likelihood function or minimizing the mean squared distance from
independence. First the problem of identification of such models is discussed.
We then state asymptotic results for a general class of nonparametric
estimators. Finally, we give some particular examples of nonparametric
estimators of transformed separable models. The small sample performance is
studied in several simulations.


title:
Dispersive CQED interactions between matter qubits and bright squeezed
  light

abstract:
  Dispersive interactions of matter qubits with bright squeezed light in a
high-Q cavity is studied. Numerical simulation shows that higher fidelity of
operations to obtain a certain phase shift of the pulse through the dispersive
light-matter interaction may be reached using bright squeezed light than that
using bright coherent light.


title: Bell correlations and equal time measurements

abstract:
  According to the Bell theorem, local hidden variable theories cannot
reproduce all the predictions of quantum mechanics. An important consequence is
that under physically reasonable assumptions quantum mechanics predicts
correlations that seem impossible to obtain from a realistic system. In this
paper, two simple binary apparatuses are discussed that can accurately mimic
correlations predicted by quantum mechanics \textit{if} the correlations are
determined by a coincidence measurement as is commonly done. It is argued that
in order to exclude local hidden variables, coincidence monitors should be
avoided.


title: A Memetic Algorithm for the Generalized Traveling Salesman Problem

abstract:
  The generalized traveling salesman problem (GTSP) is an extension of the
well-known traveling salesman problem. In GTSP, we are given a partition of
cities into groups and we are required to find a minimum length tour that
includes exactly one city from each group. The recent studies on this subject
consider different variations of a memetic algorithm approach to the GTSP. The
aim of this paper is to present a new memetic algorithm for GTSP with a
powerful local search procedure. The experiments show that the proposed
algorithm clearly outperforms all of the known heuristics with respect to both
solution quality and running time. While the other memetic algorithms were
designed only for the symmetric GTSP, our algorithm can solve both symmetric
and asymmetric instances.


title: Estimating deformations of isotropic Gaussian random fields on the plane

abstract:
  This paper presents a new approach to the estimation of the deformation of an
isotropic Gaussian random field on $\mathbb{R}^2$ based on dense observations
of a single realization of the deformed random field. Under this framework we
investigate the identification and estimation of deformations. We then present
a complete methodological package--from model assumptions to algorithmic
recovery of the deformation--for the class of nonstationary processes obtained
by deforming isotropic Gaussian random fields.


title:
Using the Incompressibility Method to obtain Local Lemma results for
  Ramsey-type Problems

abstract:
  We reveal a connection between the incompressibility method and the Lovasz
local lemma in the context of Ramsey theory. We obtain bounds by repeatedly
encoding objects of interest and thereby compressing strings. The method is
demonstrated on the example of van der Waerden numbers. It applies to lower
bounds of Ramsey numbers, large transitive subtournaments and other Ramsey
phenomena as well.


title:
Automorphs of indefinite binary quadratic forms and K3-surfaces with
  Picard number 2

abstract:
  Every indefinite binary form occurs as the Picard lattice of some K3-surface.
The group of its isometries, or automorphs, coincides with the automorphism
group of the K3-surface, but only up to finite groups. The classical theory of
automorphs for binary forms can then be applied to study these automorphism
groups. The result is a precise description of all possible automorphism groups
of ``general'' K3's with Picard number two.


title: A system of grabbing particles related to Galton-Watson trees

abstract:
  We consider a system of particles with arms that are activated randomly to
grab other particles as a toy model for polymerization. We assume that the
following two rules are fulfilled: Once a particle has been grabbed then it
cannot be grabbed again, and an arm cannot grab a particle that belongs to its
own cluster. We are interested in the shape of a typical polymer in the
situation when the initial number of monomers is large and the numbers of arms
of monomers are given by i.i.d. random variables. Our main result is a limit
theorem for the empirical distribution of polymers, where limit is expressed in
terms of a Galton-Watson tree.


title: Thermodynamics of nano-cluster phases: a unifying theory

abstract:
  We propose a unifying, analytical theory accounting for the self-organization
of colloidal systems in nano- or micro-cluster phases. We predict the
distribution of cluter sizes with respect to interaction parameters and colloid
concentration. In particular, we anticipate a proportionality regime where the
mean cluster size grows proportionally to the concentration, as observed in
several experiments. We emphasize the interest of a predictive theory in soft
matter, nano-technologies and biophysics.


title:
Direct image for multiplicative and relative K-theories from
  transgression of the families index theorem, part 3

abstract:
  This is the final part of the work started in math.DG/0611281 and
math.DG/0703916. Here the question of double fibration ois adressed both for
relative k-theory and free multiplicative K-theory. In the case of relative and
``nonfree'' multiplicative K-theory, the direct image is proved to be
functorial for double submersions.


title: Many-qubit network employing cavity QED in a decoherence-free subspace

abstract:
  We propose a many-qubit network with cavity QED by encoding qubits in
decoherence-free subspace, based on which we can implement many-logic-qubit
conditional gates by means of cavity assisted interaction with single-photon
pulses. Our scheme could not only resist collective dephasing errors, but also
much reduce the implementational steps compared to conventional methods doing
the same job, and we can also complete communications between two arbitrary
nodes. We show the details by implementing a three-logic-qubit Toffoli gate,
and explore the experimental feasibility and challenge based on currently
achievable cavity QED technologies.


title:
Influence of non-conservative optical forces on the dynamics of
  optically trapped colloidal spheres: The fountain of probability

abstract:
  We demonstrate both experimentally and theoretically that a colloidal sphere
trapped in a static optical tweezer does not come to equilibrium, but rather
reaches a steady state in which its probability flux traces out a toroidal
vortex. This non-equilibrium behavior can be ascribed to a subtle bias of
thermal fluctuations by non-conservative optical forces. The circulating sphere
therefore acts as a Brownian motor. We briefly discuss ramifications of this
effect for studies in which optical tweezers have been treated as potential
energy wells.


title:
Classical dynamics of a charged particle in a laser field beyond the
  dipole approximation

abstract:
  The classical dynamics of a charged particle traveling in a laser field
modeled by an elliptically polarized monochromatic electromagnetic plane wave
is discussed within the time reparametrization invariant form of the
non-relativistic Hamilton-Jacobi theory. The exact parametric representation
for a particle's orbit in an arbitrary plane wave background beyond the dipole
approximation and including effect of the magnetic field is derived. For an
elliptically polarized monochromatic plane wave the particle's trajectory, as
an explicit function of the laboratory frame's time, is given in terms of the
Jacobian elliptic functions, whose modulus is proportional to the laser's
intensity and depends on the polarization of radiation. It is shown that the
system exposes the ``intensity duality'', correspondence between the motion in
the backgrounds with various intensities. In virtue of the modular properties
of the Jacobian functions, by starting with the representative ``fundamental
solution'' and applying a certain modular transformations one can obtain the
particle's orbit in the monochromatic plane wave background with arbitrarily
prescribed characteristics.

categories: physics.class-ph math-ph math.MP physics.atom-ph


title:
Reply to "Comment on `Self-organized Criticality and Absorbing States:
  Lessons from the Ising Model'"

abstract:
  In [Braz. J. Phys. 30, 27 (2000)] Dickman et al. suggested that
self-organized criticality can be produced by coupling the activity of an
absorbing state model to a dissipation mechanism and adding an external drive.
We analyzed the proposed mechanism in [Phys. Rev. E 73, 025106R (2006)] and
found that if this mechanism is at work, the finite-size scaling found in
self-organized criticality will depend on the details of the implementation of
dissipation and driving. In the preceding comment [Phys. Rev. E XX, XXXX
(2008)] Alava et al. show that one avalanche exponent in the AS approach
becomes independent of dissipation and driving. In our reply we clarify their
findings and put them in the context of the original article.


title:
Complements and signed digit representations: Analysis of a
  multi-exponentiation-algorithm of Wu, Lou, Lai and Chang

abstract:
  Wu, Lou, Lai and Chang proposed a multi-exponentiation algorithm using binary
complements and the non-adjacent form. The purpose of this paper is to show
that neither the analysis of the algorithm given by its original proposers nor
that by other authors are correct. In fact it turns out that the complement
operation does not have significant influence on the performance of the
algorithm and can therefore be omitted.


title:
Modification of the thermal spin-wave spectrum in a Ni81Fe19 stripe by a
  domain wall

abstract:
  The thermal spin-wave distribution in a Ni81Fe19 stripe with an asymmetric
transverse domain wall has been investigated using Brillouin light scattering
microscopy. Clear evidence has been found that the existence of the domain wall
influences the spin-wave distribution of the thermal modes. The thermal
spin-wave modes are quantized due to the confinement in radial direction. They
vanish near the domain wall and a new mode evolves inside this complex domain
wall structure. This effect is attributed to a change of the effective internal
field in the domain wall region. The experimental results agree well with
static and dynamic micromagnetic simulations.


title: Generalized Traveling Salesman Problem Reduction Algorithms

abstract:
  The generalized traveling salesman problem (GTSP) is an extension of the
well-known traveling salesman problem. In GTSP, we are given a partition of
cities into groups and we are required to find a minimum length tour that
includes exactly one city from each group. The aim of this paper is to present
a problem reduction algorithm that deletes redundant vertices and edges,
preserving the optimal solution. The algorithm's running time is O(N^3) in the
worst case, but it is significantly faster in practice. The algorithm has
reduced the problem size by 15-20% on average in our experiments and this has
decreased the solution time by 10-60% for each of the considered solvers.


title: Algebraic curves P(x)-Q(y)=0 and functional equations

abstract:
  In this paper we give several conditions implying the irreducibility of the
algebraic curve P(x)-Q(y)=0, where P,Q are rational functions. We also apply
the results obtained to the functional equations P(f)=Q(g) and P(f)=cP(g),
where c\in C. For example, we show that for a generic pair of rational
functions P,Q the first equation has no non-constant solutions f,g meromorphic
on C whenever (\deg P-1)(\deg Q-1) \geq 2.


title: Normalized least-squares estimation in time-varying ARCH models

abstract:
  We investigate the time-varying ARCH (tvARCH) process. It is shown that it
can be used to describe the slow decay of the sample autocorrelations of the
squared returns often observed in financial time series, which warrants the
further study of parameter estimation methods for the model. Since the
parameters are changing over time, a successful estimator needs to perform well
for small samples. We propose a kernel normalized-least-squares (kernel-NLS)
estimator which has a closed form, and thus outperforms the previously proposed
kernel quasi-maximum likelihood (kernel-QML) estimator for small samples. The
kernel-NLS estimator is simple, works under mild moment assumptions and avoids
some of the parameter space restrictions imposed by the kernel-QML estimator.
Theoretical evidence shows that the kernel-NLS estimator has the same rate of
convergence as the kernel-QML estimator. Due to the kernel-NLS estimator's ease
of computation, computationally intensive procedures can be used. A
prediction-based cross-validation method is proposed for selecting the
bandwidth of the kernel-NLS estimator. Also, we use a residual-based bootstrap
scheme to bootstrap the tvARCH process. The bootstrap sample is used to obtain
pointwise confidence intervals for the kernel-NLS estimator. It is shown that
distributions of the estimator using the bootstrap and the ``true'' tvARCH
estimator asymptotically coincide. We illustrate our estimation method on a
variety of currency exchange and stock index data for which we obtain both good
fits to the data and accurate forecasts.


title:
Complex and Kaehler structures on compact homogeneous manifolds - their
  existence, classification and moduli problem

abstract:
  The existence of some complex geometrical structures on a compact manifold
such as complex structures, Kaehler (pseudo-Kaehler) structures often impose
certain restrictions on its underling topological or differentiable manifold.
In this article we survey recent developments in the study of the existence,
classification and moduli problems of such structures on compact homogeneous
manifolds.


title:
On the equation P(f)=Q(g), where P,Q are polynomials and f,g are entire
  functions

abstract:
  In 1922 Ritt described polynomial solutions of the functional equation
P(f)=Q(g). In this paper we describe solutions of the equation above in the
case when P,Q are polynomials while f,g are allowed to be arbitrary entire
functions. In fact, we describe solutions of the more general functional
equation s=P(f)=Q(g), where s,f,g are entire functions and P,Q are arbitrary
rational functions. Besides, we solve the problem of description of "strong
uniqueness polynomials" for entire functions.


title: Photon Number Statistics of Multimode Parametric Down-Conversion

abstract:
  We experimentally analyze the complete photon number statistics of parametric
downconversion and ascertain the influence of multimode effects. Our results
clearly reveal a difference between single mode theoretical description and the
measured distributions. Further investigations assure the applicability of
loss-tolerant photon number reconstruction and prove strict photon number
correlation between signal and idler modes.


title: Sequential change detection revisited

abstract:
  In sequential change detection, existing performance measures differ
significantly in the way they treat the time of change. By modeling this
quantity as a random time, we introduce a general framework capable of
capturing and better understanding most well-known criteria and also propose
new ones. For a specific new criterion that constitutes an extension to
Lorden's performance measure, we offer the optimum structure for detecting a
change in the constant drift of a Brownian motion and a formula for the
corresponding optimum performance.


title:
Statistical-mechanics approach to a reinforcement learning model with
  memory

abstract:
  We introduce a two-player model of reinforcement learning with memory. Past
actions of an iterated game are stored in a memory and used to determine
player's next action. To examine the behaviour of the model some approximate
methods are used and confronted against numerical simulations and exact master
equation. When the length of memory of players increases to infinity the model
undergoes an absorbing-state phase transition. Performance of examined
strategies is checked in the prisoner' dilemma game. It turns out that it is
advantageous to have a large memory in symmetric games, but it is better to
have a short memory in asymmetric ones.


title:
Scalable Distributed Video-on-Demand: Theoretical Bounds and Practical
  Algorithms

abstract:
  We analyze a distributed system where n nodes called boxes store a large set
of videos and collaborate to serve simultaneously n videos or less. We explore
under which conditions such a system can be scalable while serving any sequence
of demands. We model this problem through a combination of two algorithms: a
video allocation algorithm and a connection scheduling algorithm. The latter
plays against an adversary that incrementally proposes video requests.


title: Moduli of Flat Conformal Structures of Hyperbolic Type

abstract:
  To each flat conformal structure (FCS) of hyperbolic type in the sense of
Kulkarni-Pinkall, we associate, for all $\theta\in[(n-1)\pi/2,n\pi/2[$ and for
all $r>\opTan(\theta/n)$ a unique immersed hypersurface
$\Sigma_{r,\theta}=(M,i_{r,\theta})$ in $\Bbb{H}^{n+1}$ of constant
$\theta$-special Lagrangian curvature equal to $r$. We show that these
hypersurfaces smoothly approximate the boundary of the canonical hyperbolic end
associated to the FCS by Kulkarni and Pinkall and thus obtain results
concerning the continuous dependance of the hyperbolic end and of the
Kulkarni-Pinkall metric on the flat conformal structure.


title: Geometric Polarimetry - Part I: Spinors and Wave States

abstract:
  A new approach to polarization algebra is introduced. It exploits the
geometric properties of spinors in order to represent wave states consistently
in arbitrary directions in three dimensional space. In this first expository
paper of an intended series the basic derivation of the spinorial wave state is
seen to be geometrically related to the electromagnetic field tensor in the
spatio-temporal Fourier domain. Extracting the polarization state from the
electromagnetic field requires the introduction of a new element, which enters
linearly into the defining relation. We call this element the phase flag and it
is this that keeps track of the polarization reference when the coordinate
system is changed and provides a phase origin for both wave components. In this
way we are able to identify the sphere of three dimensional unit wave vectors
with the Poincare' sphere.


title: Orbital stability of the black soliton to the Gross-Pitaevskii equation

abstract:
  We establish the orbital stability of the black soliton, or kink solution,
$\v_0(x) = \th \big(\frac{x}{\sqrt{2}} \big)$, to the one-dimensional
Gross-Pitaevskii equation, with respect to perturbations in the energy space.


title: Fractal and Multifractal Time Series

abstract:
  Data series generated by complex systems exhibit fluctuations on many time
scales and/or broad distributions of the values. In both equilibrium and
non-equilibrium situations, the natural fluctuations are often found to follow
a scaling relation over several orders of magnitude, allowing for a
characterisation of the data and the generating complex system by fractal (or
multifractal) scaling exponents. In addition, fractal and multifractal
approaches can be used for modelling time series and deriving predictions
regarding extreme events. This review article describes and exemplifies several
methods originating from Statistical Physics and Applied Mathematics, which
have been used for fractal and multifractal time series analysis.


title: Controlled impact of a disk on a water surface: Cavity dynamics

abstract:
  In this paper we study the transient surface cavity which is created by the
controlled impact of a disk of radius h0 on a water surface at Froude numbers
below 200. The dynamics of the transient free surface is recorded by high speed
imaging and compared to boundary integral simulations. An excellent agreement
is found between both. The flow surrounding the cavity is measured with high
speed particle image velocimetry and is found to also agree perfectly with the
flow field obtained from the simulations. We present a simple model for the
radial dynamics of the cavity based on the collapse of an infinite cylinder.
This model accounts for the observed asymmetry of the radial dynamics between
the expansion and contraction phase of the cavity. It reproduces the scaling of
the closure depth and total depth of the cavity which are both found to scale
roughly proportional to Fr^{1/2} with a weakly Froude number dependent
prefactor. In addition, the model accurately captures the dynamics of the
minimal radius of the cavity, the scaling of the volume Vbubble of air
entrained by the process, namely Vbubble/h0^3 proportional (1 +
0.26Fr^{1/2})Fr^{1/2}, and gives insight into the axial asymmetry of the
pinch-off process.


title:
Light-by-light scattering amplitudes from generalized unitarity in
  massive QED

abstract:
  We calculate all the four-photon helicity amplitudes at the one-loop level in
a massive theory using multiple-cut methods. The amplitudes are derived in
scalar QED, QED and $\textrm{QED}^{\caln =1}$ theories. We will see the origin
of rational terms. We extend the calculation to the simplest six-photon
helicity amplitude where all photons have the same helicity.


title: Topological strings live on attractive manifolds

abstract:
  We add to the mounting evidence that the topological B model's normalized
holomorphic three-form has integral periods by demonstrating that otherwise the
B2-brane partition function is ill-defined. The resulting Calabi-Yau manifolds
are roughly fixed points of attractor flows. We propose here that any
admissible background for topological strings requires a quantized (twisted)
integrable pure spinor, yielding a quantized (twisted) generalized Calabi-Yau
structure. This proposal would imply in particular that the A model is
consistent only on those Calabi-Yau manifolds that correspond to melting
crystals. When a pure spinor is not quantized, type change occurs on positive
codimension submanifolds. We find that quantized pure spinors in topological
A-model instead change type only when crossing a coisotropic 5-brane. Quantized
generalized Calabi-Yau structures do correspond to twisted K-theory classes,
but some twisted K-theory classes correspond to either zero or to multiple
structures.


title:
An analysis of the far-field response to external forcing of a
  suspension in Stokes flow in a parallel-wall channel

abstract:
  The leading-order far-field scattered flow produced by a particle in a
parallel-wall channel under creeping flow conditions has a form of the
parabolic velocity field driven by a 2D dipolar pressure distribution. We show
that in a system of hydrodynamically interacting particles, the pressure
dipoles contribute to the macroscopic suspension flow in a similar way as the
induced electric dipoles contribute to the electrostatic displacement field.
Using this result we derive macroscopic equations governing suspension
transport under the action of a lateral force, a lateral torque or a
macroscopic pressure gradient in the channel. The matrix of linear transport
coefficients in the constitutive relations linking the external forcing to the
particle and fluid fluxes satisfies the Onsager reciprocal relation. The
transport coefficients are evaluated for square and hexagonal periodic arrays
of fixed and freely suspended particles, and a simple approximation in a
Clausius-Mossotti form is proposed for the channel permeability coefficient. We
also find explicit expressions for evaluating the periodic Green's functions
for Stokes flow between two parallel walls.


title:
Electromagnetic Dipole Moments and Radiative Decays of Particles from
  Exchange of Fermionic Unparticles

abstract:
  We construct the propagator for a free fermionic unparticle field from basic
considerations of scale and Lorentz invariance. The propagator is fixed up to a
normalization factor which is required to recover the result of a free massless
fermion field in the canonical limit of the scaling dimension. Two new features
appear compared to the bosonic case. The propagator contains both \gamma and
non-\gamma terms, and there is a relative phase of \pi/2 between the two in the
time-like regime for arbitrary scaling dimension. This should result in
additional interference effects on top of the one known in the bosonic case.
The non-\gamma term can mediate chirality flipped transitions that are not
suppressed by a light fermion mass but are enhanced by a large bosonic mass in
loops, compared to the pure particle case. We employ this last feature to set
stringent bounds on the Yukawa couplings between a fermionic unparticle and an
ordinary fermion through electromagnetic dipole moments and radiative decays of
light fermions.


title:
Quasi-randomness is determined by the distribution of copies of a fixed
  graph in equicardinal large sets

abstract:
  For every fixed graph $H$ and every fixed $0 < \alpha < 1$, we show that if a
graph $G$ has the property that all subsets of size $\alpha n$ contain the
``correct'' number of copies of $H$ one would expect to find in the random
graph $G(n,p)$ then $G$ behaves like the random graph $G(n,p)$; that is, it is
$p$-quasi-random in the sense of Chung, Graham, and Wilson. This solves a
conjecture raised by Shapira and solves in a strong sense an open problem of
Simonovits and S\'os.


title: Floating Cities, Islands and States

abstract:
  Many small countries are in need of additional territory. They build
landfills and expensive artificial islands. The ocean covers 71 per cent of the
Earth surface. Those countries (or persons of wealth) starting the early
colonization of the ocean may obtain advantages through additional territory or
creating their own independent state. An old idea is building a big ship. The
best solution to this problem, however, is the provision of floating cities,
islands, and states. The author idea is to use for floating cities, islands,
and states a cheap floating platform created from a natural ice field taken
from the Arctic or Antarctic oceans. These cheap platforms protected by
air-film (bottom and sides) and a conventional insulating cover (top) and
having a cooling system can exist for an unlimited time. They can be increased
in number or size at any time, float in warm oceans, travel to different
continents and countries, serve as artificial airports, harbors and other
marine improvements, as well as floating cities and industrial bases for
virtually any use.
  Author researches and computes parameters of these ice floating platforms,
other methods of building such floating territory, compares them and shows that
the offered method is the most cheap and efficient means of ocean colonization.


title: (D)-instanton effects in magnetized brane worlds

abstract:
  We consider systems of magnetized D9 branes on orbifolds supporting N=1 gauge
theories. In such realizations, the matter multiplets arise from "twisted"
strings connecting different stacks of branes. The introduction of Euclidean
5-branes wrapped on the six-dimensional compact space leads to instanton
effects. We examine the interplay between the annuli diagrams with an E5
boundary and the holomorphicity properties of the effective low-energy
supergravity action which describes the system, including its instanton
corrections. Mostly based on arXiv:0709.0245.


title: Betti numbers of mixed product ideals

abstract:
  We compute the Betti numbers of the resolution of a special class of
square-free monomial ideals, the ideals of mixed products. Moreover when these
ideals are Cohen-Macaulay we calculate their type.


title:
On calculation of fluxbrane polynomials corresponding to classical
  series of Lie algebras

abstract:
  We present a description of computational program (written in Maple) for
calculation of fluxbrane polynomials corresponding to classical simple Lie
algebras. These polynomials define certain special solutions to open Toda chain
equations.


title: Closed-form likelihood expansions for multivariate diffusions

abstract:
  This paper provides closed-form expansions for the log-likelihood function of
multivariate diffusions sampled at discrete time intervals. The coefficients of
the expansion are calculated explicitly by exploiting the special structure
afforded by the diffusion model. Examples of interest in financial statistics
and Monte Carlo evidence are included, along with the convergence of the
expansion to the true likelihood function.


title:
Does Face Image Statistics Predict a Preferred Spatial Frequency for
  Human Face Processing?

abstract:
  Psychophysical experiments suggested a relative importance of a narrow band
of spatial frequencies for recognition of face identity in humans. There
exists, however, no conclusive evidence of why it is that such frequencies are
preferred. To address this question, I examined the amplitude spectra of a
large number of face images, and observed that face spectra generally fall off
steeper with spatial frequency compared to ordinary natural images. When
external face features (like hair) are suppressed, then whitening of the
corresponding mean amplitude spectra revealed higher response amplitudes at
those spatial frequencies which are deemed important for processing face
identity. The results presented here therefore provide support for that face
processing characteristics match corresponding stimulus properties.


title: The X-ray luminosity function of AGN at z~3

abstract:
  We combine Lyman-break colour selection with ultradeep (> 200 ks) Chandra
X-ray imaging over a survey area of ~0.35 deg^2 to select high redshift AGN.
Applying careful corrections for both the optical and X-ray selection
functions, the data allow us to make the most accurate determination to date of
the faint end of the X-ray luminosity function (XLF) at z~3. Our methodology
recovers a number density of X-ray sources at this redshift which is at least
as high as previous surveys, demonstrating that it is an effective way of
selecting high z AGN. Comparing to results at z=1, we find no evidence that the
faint slope of the XLF flattens at high z, but we do find significant (factor
~3.6) negative evolution of the space density of low luminosity AGN. Combining
with bright end data from very wide surveys we also see marginal evidence for
continued positive evolution of the characteristic break luminosity L*. Our
data therefore support models of luminosity-dependent density evolution between
z=1 and z=3. A sharp upturn in the the XLF is seen at the very lowest
luminosities (Lx < 10^42.5 erg s^-1), most likely due to the contribution of
pure X-ray starburst galaxies at very faint fluxes.


title: Hydrodynamic lift of vesicles under shear flow in microgravity

abstract:
  The dynamics of a vesicle suspension in a shear flow between parallel plates
has been investigated under microgravity conditions, where vesicles are only
submitted to hydrodynamic effects such as lift forces due to the presence of
walls and drag forces. The temporal evolution of the spatial distribution of
the vesicles has been recorded thanks to digital holographic microscopy, during
parabolic flights and under normal gravity conditions. The collected data
demonstrates that vesicles are pushed away from the walls with a lift velocity
proportional to $\dot{\gamma} R^3/z^2$ where $\dot{\gamma}$ is the shear rate,
$R$ the vesicle radius and $z$ its distance from the wall. This scaling as well
as the dependence of the lift velocity upon vesicle aspect ratio are consistent
with theoretical predictions by Olla [J. Phys. II France {\bf 7}, 1533--1540
(1997)].


title:
Coulomb-Enhanced Spin-Orbit Splitting: The Missing Piece in the Sr2RhO4
  Puzzle

abstract:
  The outstanding discrepancy between the measured and calculated
(local-density approximation) Fermi surfaces in the well-characterized,
paramagnetic Fermi liquid Sr2RhO4 is resolved by including the spin-orbit
coupling and Coulomb repulsion. This results in an effective spin-orbit
coupling constant enhanced 2.15 times over the bare value. A simple formalism
allows discussion of other systems. For Sr2RhO4, the experimental specific-heat
and mass enhancements are found to be 2.2.


title: Higher derivative terms including the Ramond-Ramond five-form

abstract:
  Superfield methods can be used to determine the precise way the self-dual
five-form couples to the metric in the first non-trivial $\alpha'$ corrections
to type IIB supergravity. We explicitly compute the exact tensor structure of
these terms. This requires extensive use of computing algorithms to reduce the
complicated expressions that appear to a surprisingly simple form. Along the
way we show a new method of computing Schouten identities. With this result we
clarify under which conditions one may neglect the five-form higher derivative
terms. We comment on corrections to the thermodynamics of charged black holes.


title:
Photoluminescence of hexagonal boron nitride: effect of surface
  oxidation under UV-laser irradiation

abstract:
  We report on the UV laser induced fluorescence of hexagonal boron nitride
(h-BN) following nanosecond laser irradiation of the surface under vacuum and
in different environments of nitrogen gas and ambient air. The observed
fluorescence bands are tentatively ascribed to impurity and mono (VN), or
multiple (m-VN with m = 2 or 3) nitrogen vacancies. A structured fluorescence
band between 300 nm and 350 nm is assigned to impurity-band transition and its
complex lineshape is attributed to phonon replicas. An additional band at 340
nm, assigned to VN vacancies on surface, is observed under vacuum and quenched
by adsorbed molecular oxygen. UV-irradiation of h-BN under vacuum results in a
broad asymmetric fluorescence at ~400 nm assigned to m-VN vacancies; further
irradiation breaks more B-N bonds enriching the surface with elemental boron.
However, no boron deposit appears under irradiation of samples in ambient
atmosphere. This effect is explained by oxygen healing of radiation-induced
surface defects. Formation of the oxide layer prevents B-N dissociation and
preserves the bulk sample stoichiometry.


title: Pion condensation of quark matter in the static Einstein universe

abstract:
  In the framework of an extended Nambu--Jona-Lasinio model we are studying
pion condensation in quark matter with an asymmetric isospin composition in a
gravitational field of the static Einstein universe at finite temperature and
chemical potential. This particular choice of the gravitational field
configuration enables us to investigate phase transitions of the system with
exact consideration of the role of this field in the formation of quark and
pion condensates and to point out its influence on the phase portraits. We
demonstrate the effect of oscillations of the thermodynamic quantities as
functions of the curvature and also refer to a certain similarity between the
behavior of these quantities as functions of curvature and finite temperature.
Finally, the role of quantum fluctuations for spontaneous symmetry breaking in
the case of a finite volume of the universe is shortly discussed.


title:
Magnetic trapping of silver and copper, and anomolous spin relaxation in
  the Ag-He system

abstract:
  We have trapped large numbers of copper and silver atoms using buffer gas
cooling. Up to 3x10^12 copper atoms and 4x10^13 silver atoms are trapped.
Lifetimes are as long as 5 s, limited by collisions with the buffer gas. Ratios
of elastic to inelastic collision rates with He are >~ 10^6, suggesting copper
and silver are favorable for use in ultracold applications. The temperature
dependence of the silver-helium-3 collision rate varies as T^5.8. We find that
this temperature dependence is inconsistent with the behavior predicted for
relaxation arising from the spin-rotation interaction, and conclude that the
silver-helium-3 system displays anomalous collisional behavior in the
multiple-partial wave regime. Lifetimes of laser ablated gold in helium-3
buffer gas are too short to permit trapping.


title:
Phonon and Electronic Non-radiative Decay of Excitons in Carbon
  Nanotubes

abstract:
  We investigate theoretically the rates of non-radiative decay of excited
semiconducting nanotubes by a variety of decay mechanisms and compare with
experimental findings. We find that the multi-phonon decay (MPD) of free
excitons is too slow to be responsible for the experimentally observed
lifetimes. However, MPD lifetimes of localized excitons could be 2-3 orders of
magnitude shorter. We also propose a new decay mechanism that relies on a
finite doping of nanotubes and involves exciton decay into an optical phonon
and an intraband electron-hole pair. The resulting lifetime is in the range of
5 to 100 ps, even for a moderate doping level.


title: Bounds for Bayesian order identification with application to mixtures

abstract:
  The efficiency of two Bayesian order estimators is studied. By using
nonparametric techniques, we prove new underestimation and overestimation
bounds. The results apply to various models, including mixture models. In this
case, the errors are shown to be $O(e^{-an})$ and $O((\log n)^b/\sqrt{n})$
($a,b>0$), respectively.


title: Gravity Cutoff in Theories with Large Discrete Symmetries

abstract:
  We set an upper bound on the gravitational cutoff in theories with exact
quantum numbers of large N periodicity, such as Z_N discrete symmetries. The
bound stems from black hole physics. It is similar to the bound appearing in
theories with N particle species, though a priori, a large discrete symmetry
does not imply a large number of species. Thus, there emerges a potentially
wide class of new theories, that address the hierarchy problem by lowering the
gravitational cutoff due to existence of large Z_{10^32}-type symmetries.


title: Finite Temperature Behaviour of O'KKLT Model

abstract:
  We summarize our work on the O'Raifeartaigh uplifted KKLT model at finite
temperature. We study the system for parameter values for which the zero
temperature potential for the volume modulus has a dS minimum. The
temperature-dependent part of the effective potential has a runaway behaviour
for one exponent in the superpotential, whereas it can have local minima at
finite field vevs for two exponents in the superpotential. However, it turns
out that, despite the presence of those minima, the zero temperature dS vacuum
is not destabilized by thermal corrections within the whole range of validity
of our approximations.


title: Spin Lifetimes in Quantum Dots from Noise Measurements

abstract:
  We present a method of obtaining information about spin lifetimes in quantum
dots from measurements of electrical transport. The dot is under resonant
microwave irradiation and at temperatures comparable to or larger than the
Zeeman energy. We find that the ratio of the spin coherence times T_{1}/T_{2}
can be deduced from a measurement of current through the quantum dot as a
function the applied magnetic field. We calculate the noise power spectrum of
the dot current and show that a dip occurs at the Rabi frequency with a line
width given by 1/T_{1}+1/T_{2}.


title: On a redundancy in the parity-violating 2-nucleon contact Lagrangian

abstract:
  It is shown that the number of independent operators in the nucleon-nucleon
parity-violating contact Lagrangian at the leading order in the low-momentum
expansion, can be reduced to five, by using Fierz rearrangements of the nucleon
fields.


title:
Discovery of a relationship between spiral arm morphology and
  supermassive black hole mass in disk galaxies

abstract:
  We present a relationship between spiral arm pitch angle (a measure of the
tightness of spiral structure) and the mass of supermassive black holes (BHs)
in the nuclei of disk galaxies. We argue that this relationship is expected
through a combination of other relationships, whose existence has already been
demonstrated. The recent discovery of AGN in bulgeless disk galaxies suggests
that halo concentration or virial mass may be one of the determining factors in
BH mass. Taken together with the result that mass concentration seems to
determine spiral arm pitch angle, one would expect a relation to exist between
spiral arm pitch angle and supermassive BH mass in disk galaxies, and we find
that this is indeed the case. We conclude that this relationship may be
important for estimating evolution in BH masses in disk galaxies out to
intermediate redshifts, since regular spiral arm structure can be seen in
galaxies out to z~1.


title: Aeroelastic instability of cantilevered flexible plates in uniform flow

abstract:
  We address the flutter instability of a flexible plate immersed in an axial
flow. This instability is similar to flag flutter and results from the
competition between destabilising pressure forces and stabilising bending
stiffness. In previous experimental studies, the plates have always appeared
much more stable than the predictions of two-dimensional models. This
discrepancy is discussed and clarified in this paper by examining
experimentally and theoretically the effect of the plate aspect ratio on the
instability threshold. We show that the two-dimensional limit cannot be
achieved experimentally because hysteretical behaviour and three-dimensional
effects appear for plates of large aspect ratio. The nature of the instability
bifurcation (sub- or supercritical) is also discussed in the light of recent
numerical results.


title: Some consequences of reflection on the approachability ideal

abstract:
  We study the approachability ideal I[\kappa^+] in the context of large
cardinals properties of the regular cardinals below a singular \kappa. As a
guiding example consider the approachability ideal I[\aleph_{\omega+1}]
assuming that \aleph_\omega is strong limit. In this case we obtain that club
many points in \aleph_{\omega+1} of cofinality \aleph_n for some n>1 are
approachable assuming the joint reflection of countable families of stationary
subsets of \aleph_n. This reflection principle holds under Martin's maximum for
all n>1 and for each n>1 is equiconsistent with \aleph_n being weakly compact
in L. This characterizes the structure of the approachability ideal
I[\aleph_{\omega+1}] in models of Martin's maximum.


title:
Role of chaos for the validity of statistical mechanics laws: diffusion
  and conduction

abstract:
  Several years after the pioneering work by Fermi Pasta and Ulam, fundamental
questions about the link between dynamical and statistical properties remain
still open in modern statistical mechanics. Particularly controversial is the
role of deterministic chaos for the validity and consistency of statistical
approaches. This contribution reexamines such a debated issue taking
inspiration from the problem of diffusion and heat conduction in deterministic
systems. Is microscopic chaos a necessary ingredient to observe such
macroscopic phenomena?


title: Decompositions involving Anick's spaces

abstract:
  Recently Stephen Theriault and I found an elementary construction of Anick's
spaces and proved their main properties(arXiv:0710.1024).In this work the
fundamental fibration is decomposed. This is useful in studying maps out of
Anick's spaces and will be needed in order to determine it's universal
properties.


title: PT symmetry and large-N models

abstract:
  Recently developed methods for PT-symmetric models can be applied to
quantum-mechanical matrix and vector models. In matrix models, the calculation
of all singlet wave functions can be reduced to the solution a one-dimensional
PT-symmetric model. The large-N limit of a wide class of matrix models exists,
and properties of the lowest-lying singlet state can be computed using WKB. For
models with cubic and quartic interactions, the ground state energy appears to
show rapid convergence to the large-N limit. For the special case of a quartic
model, we find explicitly an isospectral Hermitian matrix model. The Hermitian
form for a vector model with O(N) symmetry can also be found, and shows many
unusual features. The effective potential obtained in the large-N limit of the
Hermitian form is shown to be identical to the form obtained from the original
PT-symmetric model using familiar constraint field methods. The analogous
constraint field prescription in four dimensions suggests that PT-symmetric
scalar field theories are asymptotically free.


title: Universal ratio as lower bound

abstract:
  We refine the definition of universal ratio c/\tilde{c} obtained via AdS/CFT
correspondence as shown in arXiv:0801.2785 [hep-th], denoted as \gamma_c, and
apply it to non-CFTs whose dual gravitational theory have metric of asymptotic
AdS. We conjecture that \gamma_c=1 is the lower bound being saturated at high
temperature regime and serves as an ordering parameter as energy scale varies.
We test this conjecture with the hard wall AdS/QCD toy model and N=2*
Pilch-Warner solution and find the agreement. At last, we make a connection
with the C-Theorem and prove this conjecture in a general holographic
background with multi-kink geometry.


title: Renormalization in the H\'enon family, II: The heteroclinic web

abstract:
  We study highly dissipative H\'enon maps $$ F_{c,b}: (x,y) \mapsto (c-x^2-by,
x) $$ with zero entropy. They form a region $\Pi$ in the parameter plane
bounded on the left by the curve $W$ of infinitely renormalizable maps. We
prove that Morse-Smale maps are dense in $\Pi$, but there exist infinitely many
different topological types of such maps (even away from $W$). We also prove
that in the infinitely renormalizable case, the average Jacobian $b_F$ on the
attracting Cantor set $\OO_F$ is a topological invariant. These results come
from the analysis of the heteroclinic web of the saddle periodic points based
on the renormalization theory. Along these lines, we show that the unstable
manifolds of the periodic points form a lamination outside $\OO_F$ if and only
if there are no heteroclinic tangencies.


title:
Kinetic Arrest in Polyion-Induced Inhomogeneously-Charged Colloidal
  Particle Aggregation

abstract:
  Polymer chains adsorbed onto oppositely charged spherical colloidal particles
can significantly modify the particle-particle interactions. For sufficient
amounts of added polymers, the original electrostatic repulsion can even turn
into an effective attraction and relatively large kinetically stable aggregates
can form which display several unexpected and interesting peculiarities and
some intriguing biotechnological implications. The attractive interaction
contribution between two oppositely particles arises from the correlated
adsorption of polyions at the oppositely charged particle surfaces, resulting
in a non-homogeneous surface charge distribution. Here, we investigate the
aggregation kinetics of polyion-induced colloidal complexes through Monte Carlo
simulation, in which the effect of charge anisotropy is taken into account by a
DLVO-like intra-particle potential, as recentely proposed by Velegol and Thwar
[D. Velegol and P.K. Thwar, Langmuir, 17, 2001]. The results reveal that in the
presence of a charge heterogeneity the aggregation process slows down due to
the progressive increase of the potential barrier height upon clustering.
Within this framework, the experimentally observed cluster phases in
polyelectrolyte-liposomes solutions should be considered as a kinetic arrested
state.


title: Collective modes in asymmetric ultracold Fermi systems

abstract:
  We derive the low energy effective action for the collective modes in systems
of fermions interacting via a short-range s-wave attraction, featuring unequal
chemical potentials for the two fermionic species (asymmetric systems). As a
consequence of the attractive interaction, fermions form a condensate that
spontaneously breaks the U(1) symmetry associated with total number
conservation. Therefore at sufficiently small temperatures and asymmetries, the
system is a superfluid. We reproduce previous results for the stability
conditions of the system as a function of the four-fermion coupling and
asymmetry. We obtain these results analyzing the coefficients of the low energy
effective Lagrangian of the modes describing fluctuations in the magnitude
(Higgs mode) and in the phase (Goldstone mode) of the difermion condensate. We
find that for certain values of parameters, the mass of the Higgs mode
decreases with increasing mismatch between the chemical potentials of the two
populations, if we keep the scattering length and the gap parameter constant.
Furthermore, we find that the energy cost for creating a position dependent
fluctuation of the condensate is constant in the gapped region and increases in
the gapless region. These two features may lead to experimentally detectable
effects. As an example, we argue that if the superfluid is put in rotation, the
square of the radius of the outer core of a vortex should sharply increase on
increasing the asymmetry, when we pass through the relevant region in the
gapless superfluid phase. Finally, by gauging the global U(1) symmetry, we
relate the coefficients of the effective Lagrangian of the Goldstone mode with
the screening masses of the gauge field.


title: Mean Curvature Flow of Spacelike Graphs

abstract:
  We prove the mean curvature flow of a spacelike graph in $(\Sigma_1\times
\Sigma_2, g_1-g_2)$ of a map $f:\Sigma_1\to \Sigma_2$ from a closed Riemannian
manifold $(\Sigma_1,g_1)$ with $Ricci_1> 0$ to a complete Riemannian manifold
$(\Sigma_2,g_2)$ with bounded curvature tensor and derivatives, and with
sectional curvatures satisfying $K_2\leq K_1$, remains a spacelike graph,
exists for all time, and converges to a slice at infinity. We also show, with
no need of the assumption $K_2\leq K_1$, that if $K_1>0$, or if $Ricci_1>0$ and
$K_2\leq -c$, $c>0$ constant, any map $f:\Sigma_1\to \Sigma_2$ is trivially
homotopic provided $f^*g_2<\rho g_1$ where
$\rho=\min_{\Sigma_1}K_1/\sup_{\Sigma_2}K_2^+\geq 0$, in case $K_1>0$, and
$\rho=+\infty$ in case $K_2\leq 0$. This largely extends some known results for
$K_i$ constant and $\Sigma_2$ compact, obtained using the Riemannian structure
of $\Sigma_1\times \Sigma_2$, and also shows how regularity theory on the mean
curvature flow is simpler and more natural in pseudo-Riemannian setting then in
the Riemannian one.


title: Modeling of graphite oxide

abstract:
  Based on density functional calculations, optimized structures of graphite
oxide are found for various coverage by oxygen and hydroxyl groups, as well as
their ratio corresponding to the minimum of total energy. The model proposed
describes well known experimental results. In particular, it explains why it is
so difficult to reduce the graphite oxide up to pure graphene. Evolution of the
electronic structure of graphite oxide with the coverage change is
investigated.


title:
Solutions of the Painleve VI Equation from Reduction of Integrable
  Hierarchy in a Grassmannian Approach

abstract:
  We present an explicit method to perform similarity reduction of a
Riemann-Hilbert factorization problem for a homogeneous GL (N, C) loop group
and use our results to find solutions to the Painleve VI equation for N=3. The
tau function of the reduced hierarchy is shown to satisfy the sigma-form of the
Painleve VI equation. A class of tau functions of the reduced integrable
hierarchy is constructed by means of a Grassmannian formulation. These
solutions provide rational solutions of the Painleve VI equation.


title: Monopole Quantum Numbers in the Staggered Flux Spin Liquid

abstract:
  Algebraic spin liquids, which are exotic gapless spin states preserving all
microscopic symmetries, have been widely studied due to potential realizations
in frustrated quantum magnets and the cuprates. At low energies, such putative
phases are described by quantum electrodynamics in 2+1 dimensions. While
significant progress has been made in understanding this nontrivial interacting
field theory and the associated spin physics, one important issue which has
proved elusive is the quantum numbers carried by so-called monopole operators.
Here we address this issue in the ``staggered-flux'' spin liquid which may be
relevant to the pseudogap regime in high-T_c. Employing general analytical
arguments supported by simple numerics, we argue that proximate phases encoded
in the monopole operators include the familiar Neel and valence bond solid
orders, as well as other symmetry-breaking orders closely related to those
previously explored in the monopole-free sector of the theory. Surprisingly, we
also find that one monopole operator carries trivial quantum numbers, and
briefly discuss its possible implications.


title: New Graphs of Finite Mutation Type

abstract:
  To a directed graph without loops and 2-cycles, we can associate a
skew-symmetric matrix with integer entries. Mutations of such skew-symmetric
matrices, and more generally skew-symmetrizable matrices, have been defined in
the context of cluster algebras by Fomin and Zelevinsky. The mutation class of
a graph G is the set of all isomorphism classes of graphs that can be obtained
from G by a sequence of mutations. A graph is called mutation-finite if its
mutation class is finite. Fomin, Shapiro and Thurston constructed
mutation-finite graphs from triangulations of oriented bordered surfaces with
marked points. We will call such graphs "of geometric type". Besides graphs
with 2 vertices, and graphs of geometric type, there are only 9 other
"exceptional" mutation classes that are known to be finite. In this paper we
introduce 2 new exceptional finite mutation classes.


title:
New Insights on the QSO Radio-Loud/Radio-Quiet Dichotomy: SDSS Spectra
  in the Context of the 4D Eigenvector1 Parameter Space

abstract:
  We search fora dichotomy/bimodality between Radio Loud (RL) and Radio Quiet
(RQ) Type 1 Active Galactic Nuclei (AGN). We examine several samples of SDSS
QSOs with high S/N optical spectra and matching FIRST/NVSS radio observations.
We use the radio data to identify the weakest RL sources with FRII structure to
define a RL/RQ boundary which corresponds to log L$_{1.4GHz}$=31.6 ergs
s$^{-1}$ Hz$^{-1}$. We measure properties of broad line H$\beta$ and FeII
emission to define the optical plane of a 4DE1 spectroscopic diagnostic space.
The RL quasars occupy a much more restricted domain in this optical plane
compared to the RQ sources, which a 2D Kolmogorov-Smirnov test finds to be
highly significant. This tells us that the range of BLR kinematics and
structure for RL sources is more restricted than for the RQ QSOs, which
supports the notion of dichotomy. FRII and CD RL sources also show significant
4DE1 domain differences that likely reflect differences in line of sight
orientation (inclined vs. face-on respectively) for these two classes. The
possibility of a distinct Radio Intermediate (RI) population between RQ and RL
source is disfavored because a 4DE1 diagnostic space comparison shows no
difference between RI and RQ sources. We show that searches for dichotomy in
radio vs. bolometric luminosity diagrams will yield ambiguous results mainly
because in a reasonably complete sample the radio brightest RQ sources will be
numerous enough to blur the gap between RQ and RL sources. Within resolution
constraints of NVSS and FIRST we find no FRI sources among the broad line
quasar population.


title: Two-dimensional Hawking radiation from the AdS/CFT correspondence

abstract:
  The AdS/CFT correspondence has been tested through the reproduction of
standard results. Following this approach, we use the correspondence to obtain
the Hawking temperature of a black hole in 1+1 dimensions. Using an auxiliary
Liouville field, the holographic energy-momentum tensor is found and compared
with a radiation energy-momentum tensor, verifying that the correspondence
gives the correct temperature. The information about the radiated field in the
CFT sector is contained in the central charge, whereas in the radiation tensor
this information is in the statistical distribution. This result allows to
determine the radiation of scalar and Dirac fields easily and without the
necessity of solving the corresponding Klein-Gordon or Dirac equation in a
curved spacetime. In both cases, the correct temperature was obtained.


title:
Outage behavior of slow fading channels with power control using noisy
  quantized CSIT

abstract:
  The topic of this study is the outage behavior of multiple-antenna slow
fading channels with quantized feedback and partial power control. A fixed-rate
communication system is considered. It is known from the literature that with
error-free feedback, the outage-optimal quantizer for power control has a
circular structure. Moreover, the diversity gain of the system increases
polynomially with the cardinality of the power control codebook. Here, a
similar system is studied, but when the feedback link is error-prone. We prove
that in the high-SNR regime, the optimal quantizer structure with noisy
feedback is still circular and the optimal Voronoi regions are contiguous
non-zero probability intervals. Furthermore, the optimal power control codebook
resembles a channel optimized scalar quantizer (COSQ), i.e., the Voronoi
regions merge with erroneous feedback information. Using a COSQ, the outage
performance of the system is superior to that of a no-feedback scheme. However,
asymptotic analysis shows that the diversity gain of the system is the same as
a no-CSIT scheme if there is a non-zero and non-vanishing feedback error
probability.


title: Analytical Characterization of Oscillon Energy and Lifetime

abstract:
  We develop an analytical procedure to compute all relevant physical
properties of scalar field oscillons in models with quartic polynomial
potentials: energy, radius, frequency, core-amplitude, and lifetime. We compare
our predictions to numerical simulations of models with symmetric and
asymmetric double well potentials in three spatial dimensions, obtaining
excellent agreement. We also explain why oscillons have not been seen to decay
in two spatial dimensions.


title:
Correlation effects in the electronic structure of Mn$_4$ molecular
  magnet

abstract:
  We present joint theoretical-experimental study of the correlation effects in
the electronic structure of (pyH)$_3$[Mn$_4$O$_3$Cl$_7$(OAc)$_3$]$\cdot$2MeCN
molecular magnet (Mn$_4$). Describing the many-body effects by cluster
dynamical mean-field theory, we find that Mn$_4$ is predominantly Hubbard
insulator with strong electron correlations. The calculated electron gap (1.8
eV) agrees well with the results of optical conductivity measurements, while
other methods, which neglect many-body effects or treat them in a simplified
manner, do not provide such an agreement. Strong electron correlations in
Mn$_4$ may have important implications for possible future applications.


title:
Quantum algebra of the Hamiltonian constraint in reduced
  four-dimensional gravity

abstract:
  In this paper we demonstrate closure of the quantum algebra of Hamiltonian
constraints in a theory directly related to a certain sector of general
relativity reduced to diagonal variables.


title:
Abelian solutions of the soliton equations and geometry of abelian
  varieties

abstract:
  We introduce the notion of abelian solutions of the 2D Toda lattice equations
and the bilinear discrete Hirota equation and show that all of them are
algebro-geometric.


title:
Magnetic Order versus superconductivity in the Iron-based layered
  La(O1-xFx)FeAs systems

abstract:
  In high-transition temperature (high-Tc) copper oxides, it is generally
believed that antiferromagnetism plays a fundamental role in the
superconducting mechanism because superconductivity occurs when mobile
electrons or holes are doped into the antiferromagnetic parent compounds. The
recent discovery of superconductivity in the rare-earth (R) iron-based oxide
systems [RO1-xFxFeAs] has generated enormous interest because these materials
are the first noncopper oxide superconductors with Tc exceeding 50 K. The
parent (nonsuperconducting) LaOFeAs material is metallic but shows anomalies
near 150 K in both resistivity and dc magnetic susceptibility. While optical
conductivity and theoretical calculations suggest that LaOFeAs exhibits a
spin-density-wave (SDW) instability that is suppressed with doping electrons to
form superconductivity, there has been no direct evidence of the SDW order.
Here we use neutron scattering to demonstrate that LaOFeAs undergoes an abrupt
structural distortion below ~150 K, changing the symmetry from tetragonal
(space group P4/nmm) to monoclinic (space group P112/n) at low temperatures,
and then followed with the development of long range SDW-type antiferromagnetic
order at ~134 K with a small moment but simple magnetic structure. Doping the
system with flourine suppresses both the magnetic order and structural
distortion in favor of superconductivity. Therefore, much like high-Tc copper
oxides, the superconducting regime in these Fe-based materials occurs in close
proximity to a long-range ordered antiferromagnetic ground state. Since the
discovery of long


title: Evidence for the Spin Density Wave in LaFeAsO

abstract:
  This paper has been withdrawn by the authors due to errors in the X-ray
diffraction data. Other measured data are not affected; however, the errors
significantly change the interpretation and conclusions, and thus warrant
withdrawal and later resubmission.


title: Sarbanes-Oxley: What About all the Spreadsheets?

abstract:
  The Sarbanes-Oxley Act of 2002 has finally forced corporations to examine the
validity of their spreadsheets. They are beginning to understand the
spreadsheet error literature, including what it tells them about the need for
comprehensive spreadsheet testing. However, controlling for fraud will require
a completely new set of capabilities, and a great deal of new research will be
needed to develop fraud control capabilities. This paper discusses the
riskiness of spreadsheets, which can now be quantified to a considerable
degree. It then discusses how to use control frameworks to reduce the dangers
created by spreadsheets. It focuses especially on testing, which appears to be
the most crucial element in spreadsheet controls.


title:
Darwin Tames an Andromeda Dwarf: Unraveling the Orbit of NGC 205 Using a
  Genetic Algorithm

abstract:
  NGC 205, a close satellite of the M31 galaxy, is our nearest example of a
dwarf elliptical galaxy. Photometric and kinematic observations suggest that
NGC 205 is undergoing tidal distortion from its interaction with M31. Despite
earlier attempts, the orbit and progenitor properties of NGC 205 are not well
known. We perform an optimized search for these unknowns by combining a genetic
algorithm with restricted N-body simulations of the interaction. This approach,
coupled with photometric and kinematic observations as constraints, allows for
an effective exploration of the parameter space. We represent NGC 205 as a
static Hernquist potential with embedded massless test particles that serve as
tracers of surface brightness. We explore 3 distinct, initially stable
configurations of test particles: cold rotating disk, warm rotating disk, and
hot, pressure-supported spheroid. Each model reproduces some, but not all, of
the observed features of NGC 205, leading us to speculate that a rotating
progenitor with substantial pressure support could match all of the
observables. Furthermore, plausible combinations of mass and scale length for
the pressure-supported spheroid progenitor model reproduce the observed
velocity dispersion profile. For all 3 models, orbits that best match the
observables place the satellite 11+/-9 kpc behind M31 moving at very large
velocities: 300-500 km/s on primarily radial orbits. Given that the observed
radial component is only 54 km/s, this implies a large tangential motion for
NGC 205, moving from the NW to the SE. These results suggest NGC 205 is not
associated with the stellar arc observed to the NE of NGC 205. Furthermore, NGC
205's velocity appears to be near or greater than its escape velocity,
signifying that the satellite is likely on its first M31 passage.


title: Constraining Anisotropic Baryon Oscillations

abstract:
  We present an analysis of anisotropic baryon acoustic oscillations and
elucidate how a mis-estimation of the cosmology, which leads to incorrect
values of the angular diameter distance, d_A, and Hubble parameter, H, manifest
themselves in changes to the monopole and quadrupole power spectrum of biased
tracers of the density field. Previous work has focused on the monopole power
spectrum, and shown that the isotropic "dilation" combination d_A^2/H is
robustly constrained by an overall shift in the scale of the baryon feature. We
extend this by demonstrating that the quadrupole power spectrum is sensitive to
an anisotropic "warping" mode d_A H, allowing one to break the degeneracy
between d_A and H. We describe a method for measuring this warping, explicitly
marginalizing over the form of redshift space distortions. We verify this
method on N-body simulations and estimate that d_A H can be measured with a
fractional accuracy of ~ 3/sqrt(V) % where the survey volume is estimated in
(Gpc/h)^3.


title:
The LSC Glitch Group : Monitoring Noise Transients during the fifth LIGO
  Science Run

abstract:
  The LIGO Scientific Collaboration (LSC) glitch group is part of the LIGO
detector characterization effort. It consists of data analysts and detector
experts who, during and after science runs, collaborate for a better
understanding of noise transients in the detectors. Goals of the glitch group
during the fifth LIGO science run (S5) included (1) offline assessment of the
detector data quality, with focus on noise transients, (2) veto recommendations
for astrophysical analysis and (3) feedback to the commissioning team on
anomalies seen in gravitational wave and auxiliary data channels. Other
activities included the study of auto-correlation of triggers from burst
searches, stationarity of the detector noise and veto studies. The group
identified causes for several noise transients that triggered false alarms in
the gravitational wave searches; the times of such transients were identified
and vetoed from the data generating the LSC astrophysical results.


title: A new, direct link between the baryon asymmetry and neutrino masses

abstract:
  We point out that, in a class of SO(10) models with matter fields in 16 and
10 representations and type II realization of the seesaw mechanism, the light
neutrino masses and the CP asymmetry needed for leptogenesis are controlled by
one and the same set of couplings. The generated baryon asymmetry then directly
depends on the low-energy neutrino parameters, with no unknown seesaw-scale
flavour parameters involved; in particular, the necessary CP violation is
provided by the CP-violating phases of the lepton mixing matrix. We compute the
CP asymmetry in triplet decays for this scenario and show that it can lead to
successful leptogenesis.


title: The Power of Unentanglement

abstract:
  The class QMA(k), introduced by Kobayashi et al., consists of all languages
that can be verified using k unentangled quantum proofs. Many of the simplest
questions about this class have remained embarrassingly open: for example, can
we give any evidence that k quantum proofs are more powerful than one? Does
QMA(k)=QMA(2) for k>=2? Can QMA(k) protocols be amplified to exponentially
small error? In this paper, we make progress on all of the above questions.
First, we give a protocol by which a verifier can be convinced that a 3SAT
formula of size n is satisfiable, with constant soundness, given ~O(sqrt(n))
unentangled quantum witnesses with O(log n) qubits each. Our protocol relies on
the existence of very short PCPs. Second, we show that assuming a weak version
of the Additivity Conjecture from quantum information theory, any QMA(2)
protocol can be amplified to exponentially small error, and QMA(k)=QMA(2) for
all k>=2. Third, we prove the nonexistence of "perfect disentanglers" for
simulating multiple Merlins with one.


title:
The Hard X-ray Spectrum as a Probe for Black-Hole Growth in Radio-Quiet
  Active Galactic Nuclei

abstract:
  We study the hard-X-ray spectral properties of ten highly luminous
radio-quiet (RQ) active galactic nuclei (AGNs) at z=1.3-3.2, including new
XMM-Newton observations of four of these sources. We find a significant
correlation between the normalized accretion rate (L/L_Edd) and the hard-X-ray
photon index (Gamma) for 35 moderate-high luminosity RQ AGNs including our ten
highly luminous sources. Within the limits of our sample, we show that a
measurement of Gamma and L_X can provide an estimate of L/L_Edd and black-hole
(BH) mass (M_BH) with a mean uncertainty of a factor of <~3 on the predicted
values of these properties. This may provide a useful probe for tracing the
history of BH growth in the Universe, utilizing samples of X-ray-selected AGNs
for which L/L_Edd and M_BH have not yet been determined systematically. It may
prove to be a useful way to probe BH growth in distant Compton-thin type 2
AGNs. We also find that the optical-X-ray spectral slope (a_ox) depends
primarily on optical-UV luminosity rather than on L/L_Edd in a sample of RQ
AGNs spanning five orders of magnitude in luminosity and over two orders of
magnitude in L/L_Edd. We detect a significant Compton-reflection continuum in
two of our highly luminous sources, and in the stacked X-ray spectrum of seven
other sources with similar luminosities, we obtain a mean relative Compton
reflection of R=0.9^{+0.6}_{-0.5} and an upper limit on the rest-frame
equivalent width of a neutral Fe Ka line of 105 eV. We do not detect a
significant steepening of the X-ray power-law spectrum below rest-frame 2 keV
in any of our highly luminous sources, suggesting that a soft-excess feature,
commonly observed in local AGNs, either does not depend strongly on L/L_Edd, or
is not accessible at high redshifts using current X-ray detectors. [Abridged]


title:
Gauging Spacetime Symmetries On The Worldsheet And The Geometric
  Langlands Program -- II

abstract:
  We generalise the analysis carried out in [arXiv:0710.5796], and find that
our previous results can be extended beyond the case of SL(N,C). In particular,
we show that an equivalence--at the level of the holomorphic chiral
algebra--between a bosonic string on a smooth coset manifold G/B and a B-gauged
version of itself on G, will imply an isomorphism of classical W-algebras and a
level relation which underlie a geometric Langlands correspondence for the
simply-laced, complex ADE-groups. In addition, as opposed to line operators and
branes of an open topological sigma-model, the Hecke operators and Hecke
eigensheaves, can, instead, be physically interpreted in terms of the
correlation functions of local operators in the holomorphic chiral algebra of a
closed, quasi-topological sigma-model. Our present results thus serve as an
alternative physical interpretation--to that of an electric-magnetic duality of
four-dimensional gauge theory demonstrated earlier by Kapustin and Witten in
[arXiv:hep-th/0604151]--of the geometric Langlands correspondence for complex
ADE-groups. The cases with tame and mild "ramifications" are also discussed.


title:
Finite-temperature conductance signatures of quantum criticality in
  double quantum dots

abstract:
  We study the linear conductance through a double-quantum-dot system
consisting of an interacting dot in its Kondo regime and an effectively
noninteracting dot, connected in parallel to metallic leads. Signatures in the
zero-bias conductance at temperatures $T>0$ mark a pair of quantum (T=0) phase
transitions between a Kondo-screened many-body ground state and non-Kondo
ground states. Notably, the conductance features become more prominent with
increasing $T$, which enhances the experimental prospects for accessing the
quantum-critical region through tuning of gate voltages in a single device.


title:
A quantum stochastic calculus approach to modeling double-pass
  atom-field coupling

abstract:
  We examine a proposal by Sherson and Moelmer to generate
polarization-squeezed light in terms of the quantum stochastic calculus (QSC).
We investigate the statistics of the output field and confirm their results
using the QSC formalism. In addition, we study the atomic dynamics of the
system and find that this setup can produce up to 3 dB of atomic spin
squeezing.


title: The 2-generalized knot group determines the knot

abstract:
  Generalized knot groups $G_n(K)$ were introduced independently by Kelly
(1991) and Wada (1992). We prove that $G_2(K)$ determines the unoriented knot
type and sketch a proof of the same for $G_n(K)$ for $n>2$.


title:
The fluctuations in the number of points on a hyperelliptic curve over a
  finite field

abstract:
  The number of points on a hyperelliptic curve over a field of $q$ elements
may be expressed as $q+1+S$ where $S$ is a certain character sum. We study
fluctuations of $S$ as the curve varies over a large family of hyperelliptic
curves of genus $g$. For fixed genus and growing $q$, Katz and Sarnak showed
that $S/\sqrt{q}$ is distributed as the trace of a random $2g\times 2g$ unitary
symplectic matrix. When the finite field is fixed and the genus grows, we find
that the the limiting distribution of $S$ is that of a sum of $q$ independent
trinomial random variables taking the values $\pm 1$ with probabilities
$1/2(1+q^{-1})$ and the value 0 with probability $1/(q+1)$. When both the genus
and the finite field grow, we find that $S/\sqrt{q}$ has a standard Gaussian
distribution.


title: Gevrey solutions for irregular hypergeometric systems I

abstract:
  We describe the Gevrey solutions at singular points of irregular
hypergeometric systems (GKZ systems) associated with affine monomial curves.


title:
Cosmic Strings as the Source of Small-Scale Microwave Background
  Anisotropy

abstract:
  Cosmic string networks generate cosmological perturbations actively
throughout the history of the universe. Thus, the string sourced anisotropy of
the cosmic microwave background is not affected by Silk damping as much as the
anisotropy seeded by inflation. The spectrum of perturbations generated by
strings does not match the observed CMB spectrum on large angular scales
(l<1000) and is bounded to contribute no more than 10% of the total power on
those scales. However, when this bound is marginally saturated, the anisotropy
created by cosmic strings on small angular scales l>2000 will dominate over
that created by the primary inflationary perturbations. This range of angular
scales in the CMB is presently being measured by a number of experiments; their
results will test this prediction of cosmic string networks soon.


title: The Early-time Optical Properties of Gamma-Ray Burst Afterglows

abstract:
  We present a multiwavelength analysis of 63 Gamma-Ray Bursts observed with
the world's three largest robotic optical telescopes, the Liverpool and Faulkes
Telescopes (North and South). Optical emission was detected for 24 GRBs with
brightnesses ranging from R = 10 to 22 mag in the first 10 minutes after the
burst. By comparing optical and X-ray light curves from t = 100 to about 10^6
seconds, we introduce four main classes, defined by the presence or absence of
temporal breaks at optical and/or X-ray wavelengths. While 15/24 GRBs can be
modelled with the forward-shock model, explanation of the remaining nine is
very challenging in the standard framework even with the introduction of energy
injection or an ambient density gradient. Early X-ray afterglows, even segments
of light curves described by a power-law, may be due to additional emission
from the central engine. 39 GRBs in our sample were not detected and have deep
upper limits (R < 22 mag) at early time. Of these, only ten were identified by
other facilities, primarily at near infrared wavelengths, resulting in a dark
burst fraction of about 50%. Additional emission in the early time X-ray
afterglow due to late-time central engine activity may also explain some dark
bursts by making the bursts brighter than expected in the X-ray band compared
to the optical band.


title: Theory of quantum noise detectors based on resonant tunneling

abstract:
  We propose to use the phenomenon of resonant tunneling for the detection of
noise. The main idea of this method relies on the effect of homogeneous
broadening of the resonant tunneling peak induced by the emission and
absorption of collective charge excitations in the measurement circuit. In
thermal equilibrium, the signal to noise ratio of the detector as a function of
the detector bandwidth (the detector function) is given by the universal
hyperbolic tangent, which is the statement of the fluctuation-dissipation
theorem. The universality breaks down if non-equilibrium processes take place
in the measurement circuit. We propose the theory of this phenomenon and make
predictions for the detector function in case when non-equilibrium noise is
created by a mesoscopic conductor. We investigate measurement circuit effects
and prove the universality of the classical noise detection. Finally, we
evaluate the contribution of the third cumulant of current and make suggestions
of how it can be measured.


title: Spatial Interference Cancelation for Mobile Ad Hoc Networks: Perfect CSI

abstract:
  Interference between nodes directly limits the capacity of mobile ad hoc
networks. This paper focuses on spatial interference cancelation with perfect
channel state information (CSI), and analyzes the corresponding network
capacity. Specifically, by using multiple antennas, zero-forcing beamforming is
applied at each receiver for canceling the strongest interferers. Given spatial
interference cancelation, the network transmission capacity is analyzed in this
paper, which is defined as the maximum transmitting node density under
constraints on outage and the signal-to-interference-noise ratio. Assuming the
Poisson distribution for the locations of network nodes and spatially i.i.d.
Rayleigh fading channels, mathematical tools from stochastic geometry are
applied for deriving scaling laws for transmission capacity. Specifically, for
small target outage probability, transmission capacity is proved to increase
following a power law, where the exponent is the inverse of the size of antenna
array or larger depending on the pass loss exponent. As shown by simulations,
spatial interference cancelation increases transmission capacity by an order of
magnitude or more even if only one extra antenna is added to each node.


title: Sensors as Information Transducers

abstract:
  This chapter reviews the mechanisms by which sensors gather information from
the physical world and transform it into the electronic signals that are used
in today's information and control systems. It introduces a new methodology for
describing sensing mechanisms based on the process of information flow and
applies it to the broad spectrum of sensors, instruments and data input devices
in current use. We identify four distinct elemental transduction processes:
energy conversion, energy dispersion, energy modulation and modulation of a
material property. We posit that these four mechanisms form a complete set for
describing information transduction in sensing systems.


title: Large tilting modules and representation type

abstract:
  We study finiteness conditions on large tilting modules over arbitrary rings.
We then turn to a hereditary artin algebra R and apply our results to the
(infinite dimensional) tilting module L that generates all modules without
preprojective direct summands. We show that the behaviour of L over its
endomorphism ring determines the representation type of R. A similar result
holds true for the (infinite dimensional) tilting module W that generates the
divisible modules. Finally, we extend to the wild case some results on Baer
modules and torsion-free modules proven in [AHT] for tame hereditary algebras.


title: On Nichols algebras with standard braiding

abstract:
  The class of standard braided vector spaces, introduced by Andruskiewitsch
and the author in \texttt{arXiv:math/0703924v2} to understand the proof of a
theorem of Heckenberger \cite{H2}, is slightly more general than the class of
braided vector spaces of Cartan type. In the present paper, we classify
standard braided vector spaces with finite-dimensional Nichols algebra. For any
such braided vector space, we give a PBW-basis, a closed formula of the
dimension and a presentation by generators and relations of the associated
Nichols algebra.


title:
Controlled fabrication of single electron transistors from single-walled
  carbon nanotubes

abstract:
  Single electron transistors (SETs) are fabricated by placing single walled
carbon nanotubes (SWNTs) on a 100 nm wide local Al/Al2O3 bottom gate and then
contacting with Pd electrodes. Coulomb oscillations up to 125 K were observed
and charging energies of 12-15 meV with level spacing of ~5 meV were measured
from the Couloumb diamond, in agreement with a dot size of ~100 nm, implying
that the local gate defines the dot size by bending SWNT at the edges and
controls its operation. This "mechanical template" approach may facilitate
large scale fabrication of SET devices using SWNT.


title: Effect of Distance Errors: Applications to SDSS Early-Type Galaxies

abstract:
  Noisy distance estimates associated with photometric rather than
spectroscopic redshifts lead to a mis-estimate of the luminosities, and produce
a correlated mis-estimate of the sizes. We consider a sample of early-type
galaxies from the SDSS DR6 and apply the generalization of the V_max method to
correct for these biases. We show that our technique recovers the true
redshift, magnitude and size distributions, as well as the true size-luminosity
relation. Regardless the specific application outlined here, our method impacts
a broader range of studies, when at least one distance-dependent quantity is
involved.


title: Kalman Filtered Compressed Sensing

abstract:
  We consider the problem of reconstructing time sequences of spatially sparse
signals (with unknown and time-varying sparsity patterns) from a limited number
of linear "incoherent" measurements, in real-time. The signals are sparse in
some transform domain referred to as the sparsity basis. For a single spatial
signal, the solution is provided by Compressed Sensing (CS). The question that
we address is, for a sequence of sparse signals, can we do better than CS, if
(a) the sparsity pattern of the signal's transform coefficients' vector changes
slowly over time, and (b) a simple prior model on the temporal dynamics of its
current non-zero elements is available. The overall idea of our solution is to
use CS to estimate the support set of the initial signal's transform vector. At
future times, run a reduced order Kalman filter with the currently estimated
support and estimate new additions to the support set by applying CS to the
Kalman innovations or filtering error (whenever it is "large").


title:
Inhomogeneous Gilbert damping from impurities and electron-electron
  interactions

abstract:
  We present a unified theory of magnetic damping in itinerant electron
ferromagnets at order $q^2$ including electron-electron interactions and
disorder scattering. We show that the Gilbert damping coefficient can be
expressed in terms of the spin conductivity, leading to a Matthiessen-type
formula in which disorder and interaction contributions are additive. In a weak
ferromagnet regime, electron-electron interactions lead to a strong enhancement
of the Gilbert damping.


title:
Signature of Magnetic Phase Separation in the Ground State of
  Pr1-xCaxMnO3

abstract:
  Neutron scattering has been used to investigate the evolution of the long-
and short-range charge-ordered (CO), ferromagnetic (FM), and antiferromagnetic
(AF) correlations in single crystals of Pr1-xCaxMnO3. The existence and
population of spin clusters as refected by short-range correlations are found
to drastically depend on the doping (x) and temperature (T). Concentrated spin
clusters coexist with long-range canted AF order in a wide temperature range in
x = 0.3 while clusters do not appear in x = 0.4 crystal. In contrast, both CO
and AF order parameters in the x = 0.35 crystal show a precipitous decrease
below ~ 35 K where spin clusters form. These results provide direct evidence of
magnetic phase separation and indicate that there is a critical doping x_c
(close to x = 0.35) that divides the phase-separated site-centered from the
homogeneous bond-centered or charge-disproportionated CO ground state.


title: The Different Structures of the Two Classes of Starless Cores

abstract:
  We describe a model for the thermal and dynamical equilibrium of starless
cores that includes the radiative transfer of the gas and dust and simple CO
chemistry. The model shows that the structure and behavior of the cores is
significantly different depending on whether the central density is either
above or below about 10^5 cm-3. This density is significant as the critical
density for gas cooling by gas-dust collisions and also as the critical density
for dynamical stability, given the typical properties of the starless cores.
The starless cores thus divide into two classes that we refer to as thermally
super-critical and thermally sub-critical.This two-class distinction allows an
improved interpretation of the different observational data of starless cores
within a single model.


title:
Twisted Burnside Theory for the Discrete Heisenberg Group and for Wreath
  Products of Some Groups

abstract:
  The RP-property of Fel'shtyn and Troitsky is proved for wreath products of
finitely generated Abelian groups with the group of integers. Such wreath
products become the first known example of finitely generated RP-groups being
not almost polycyclic.


title:
Evidence for High Tc Superconducting Transitions in Isolated Al45- and
  Al47- Nanoclusters

abstract:
  Heat capacities measured for Al45- and Al47- nanoclusters have reproducible
jumps at ~ 200 K. These jumps are consistent with theoretical predictions that
some clusters with highly degenerate electronic states near the Fermi level
will undergo a transition into a high Tc superconducting state. An analysis
based on a theoretical treatment of pairing in Al45- and Al47- agrees well with
the experimental data in both the value of the critical temperature and in the
size and width of the jumps in the heat capacity.


title:
Parametric Excitation, Localization and Synchronization in Nonlinear
  Hydrodynamical Systems

abstract:
  The dissertation contains 4 original chapters:
  1) Parametric excitation of Soret-driven convection of binary mixture in a
horizontal porous layer.
  2) Soret-driven convection in a horizontal porous layer from a heat or
concentration source.
  3) Localization of convective flows under randomly inhomogeneous heating.
  4) Synchrony of nonlinear systems driven by common noise.


title: Toward better simulations of planetary nebulae luminosity functions

abstract:
  We describe a procedure for the numerical simulation of the planetary nebulae
luminosity function (PNLF), improving on previous work (Mendez & Soffner 1997).
Earlier PNLF simulations were based on an imitation of the observed
distribution of the intensities of [O III] 5007 relative to Hbeta, generated
predominantly using random numbers. We are now able to replace this by a
distribution derived from the predictions of hydrodynamical PN models
(Schoenberner et al. 2007), which are made to evolve as the central star moves
across the HR diagram, using proper initial and boundary conditions. In this
way we move one step closer to a physically consistent procedure for the
generation of a PNLF. As an example of these new simulations, we have been able
to reproduce the observed PNLF in the Small Magellanic Cloud.


title: Ultracold Plasma Expansion in a Magnetic Field

abstract:
  We measure the expansion of an ultracold plasma across the field lines of a
uniform magnetic field. We image the ion distribution by extracting the ions
with a high voltage pulse onto a position-sensitive detector. Early in the
lifetime of the plasma ($< 20$ $\mu$s), the size of the image is dominated by
the time-of-flight Coulomb explosion of the dense ion cloud. For later times,
we measure the 2-D Gaussian width of the ion image, obtaining the transverse
expansion velocity as a function of magnetic field (up to 70 G). We observe
that the expansion velocity scales as B$^{-1/2}$, explained by a nonlinear
ambipolar diffusion model with anisotropic diffusion in two different
directions.


title: Spitzer Observations of M33 and the Hot Star, H II Region Connection

abstract:
  We have observed emission lines of [S IV] 10.51, H(7-6) 12.37, [Ne II] 12.81,
[Ne III] 15.56, and [S III] 18.71 um in a number of extragalactic H II regions
with the Spitzer Space Telescope. A previous paper presented our data and
analysis for the substantially face-on spiral galaxy M83. Here we report our
results for the local group spiral galaxy M33. The nebulae selected cover a
wide range of galactocentric radii (R_G). The observations were made with the
Infrared Spectrograph with the short wavelength, high resolution module. The
above set of five lines is observed cospatially, thus permitting a reliable
comparison of the fluxes. From the measured fluxes, we determine the ionic
abundance ratios including Ne++/Ne+, S3+/S++, and S++/Ne+ and find that there
is a correlation of increasingly higher ionization with larger R_G. By sampling
the dominant ionization states of Ne (Ne+, Ne++) and S (S++, S3+) for H II
regions, we can estimate the Ne/H, S/H, and Ne/S ratios. We find from linear
least-squares fits that there is a decrease in metallicity with increasing R_G:
d log (Ne/H)/dR_G = -0.058+-0.014 and d log (S/H)/dR_G = -0.052+-0.021 dex
kpc-1. There is no apparent variation in the Ne/S ratio with R_G. Unlike our
previous similar study of M83, where we conjectured that this ratio was an
upper limit, for M33 the derived ratios are likely a robust indication of Ne/S.
This occurs because the H II regions have lower metallicity and higher
ionization than those in M83. Both Ne and S are primary elements produced in
alpha-chain reactions, following C and O burning in stars, making their yields
depend very little on the stellar metallicity. Thus, it is expected that Ne/S
remains relatively constant throughout a galaxy. The median (average) Ne/S
ratio derived for H II regions in M33 is 16.3 (16.9), just slightly higher than


title:
A novel canard-based mechanism for mixed-mode oscillations in a neuronal
  model

abstract:
  We analyze a biophysical model of a neuron from the entorhinal cortex that
includes persistent sodium and slow potassium as non-standard currents using
reduction of dimension and dynamical systems techniques to determine the
mechanisms for the generation of mixed-mode oscillations. We have found that
the standard spiking currents (sodium and potassium) play a critical role in
the analysis of the interspike interval. To study the mixed-mode oscillations,
the six dimensional model has been reduced to a three dimensional model for the
subthreshold regime. Additional transformations and a truncation have led to a
simplified model system with three timescales that retains many properties of
the original equations, and we employ this system to elucidate the underlying
structure and explain a novel mechanism for the generation of mixed-mode
oscillations based on the canard phenomenon. In particular, we prove the
existence of a special solution, a singular primary canard, that serves as a
transition between mixed-mode oscillations and spiking in the singular limit by
employing appropriate rescalings, center manifold reductions, and energy
arguments. Additionally, we conjecture that the singular canard solution is the
limit of a family of canards and provide numerical evidence for the conjecture.


title: Time Travel and the Reality of Spontaneity

abstract:
  Contrary to the informed consensus, time travel implies spontaneity (as
distinct from chance) so that time travel can only be of the second kind.


title: Search for B+ -> D*+ pi0 decay

abstract:
  We report on a search for the doubly Cabibbo suppressed decay B+ -> D*+ pi0,
based on a data sample of 657 million BBbar pairs collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider.
We find no significant signal and set an upper limit of Br(B+ -> D*+ pi0) < 3.6
x 10^-6 at the 90% confidence level. This limit can be used to constrain the
ratio between suppressed and favored B -> D* pi decay amplitudes, r < 0.051, at
the 90% confidence level.