title: Performance of the Near-infrared coronagraphic imager on Gemini-South

abstract:
  We present the coronagraphic and adaptive optics performance of the
Gemini-South Near-Infrared Coronagraphic Imager (NICI). NICI includes a
dual-channel imager for simultaneous spectral difference imaging, a dedicated
85-element curvature adaptive optics system, and a built-in Lyot coronagraph.
It is specifically designed to survey for and image large extra-solar gaseous
planets on the Gemini Observatory 8-meter telescope in Chile. We present the
on-sky performance of the individual subsystems along with the end-to-end
contrast curve. These are compared to our model predictions for the adaptive
optics system, the coronagraph, and the spectral difference imaging.


title:
Dependence of Ridge Formation on Trigger Azimuth: Correlated Emission
  Model

abstract:
  Ridge formation in near-side correlation in heavy-ion collisions is studied
in the framework of a phenomenological model, called Correlated Emission Model
(CEM). Successive soft emissions due to jet-medium interaction lead to the
enhancement of thermal partons which follow the local flow directions. The
correlation between the flow direction and the semihard parton direction is the
major factor that causes the ridge formation to depend on the trigger direction
relative to the reaction plane. With the use of a few parameters we have been
able to reproduce the data on the ridge yields as functions of the trigger
azimuthal angle for different centralities. An inside-outside asymmetry
function is proposed to further probe the characteristics of the azimuthal
correlation function. Insights are provided for the understanding of some
detailed aspects of the centrality dependence.


title:
Post-selection technique for quantum channels with applications to
  quantum cryptography

abstract:
  We propose a general method for studying properties of quantum channels
acting on an n-partite system, whose action is invariant under permutations of
the subsystems. Our main result is that, in order to prove that a certain
property holds for any arbitrary input, it is sufficient to consider the
special case where the input is a particular de Finetti-type state, i.e., a
state which consists of n identical and independent copies of an (unknown)
state on a single subsystem. A similar statement holds for more general
channels which are covariant with respect to the action of an arbitrary finite
or locally compact group.
  Our technique can be applied to the analysis of information-theoretic
problems. For example, in quantum cryptography, we get a simple proof for the
fact that security of a discrete-variable quantum key distribution protocol
against collective attacks implies security of the protocol against the most
general attacks. The resulting security bounds are tighter than previously
known bounds obtained by proofs relying on the exponential de Finetti theorem
[Renner, Nature Physics 3,645(2007)].


title:
Observing Strategies for the NICI Campaign to Directly Image Extrasolar
  Planets

abstract:
  We discuss observing strategy for the Near Infrared Coronagraphic Imager
(NICI) on the 8-m Gemini South telescope. NICI combines a number of techniques
to attenuate starlight and suppress superspeckles: 1) coronagraphic imaging, 2)
dual channel imaging for Spectral Differential Imaging (SDI) and 3) operation
in a fixed Cassegrain rotator mode for Angular Differential Imaging (ADI). NICI
will be used both in service mode and for a dedicated 50 night planet search
campaign. While all of these techniques have been used individually in large
planet-finding surveys, this is the first time ADI and SDI will be used with a
coronagraph in a large survey. Thus, novel observing strategies are necessary
to conduct a viable planet search campaign.


title:
Optimal Adaptive Nonparametric Denoising of Multidimensional - Time
  Signal

abstract:
  We construct an adaptive asymptotically optimal in the classical norm of the
space L(2) of square integrable functions non - parametrical multidimensional
time defined signal regaining (adaptive filtration, noise canceller) on the
background noise via multidimensional truncated Legendre expansion and optimal
experience design. The two - dimensional case is known as a picture processing,
picture analysis or image processing. We offer a two version of an confidence
region building, also adaptive. Our estimates proposed by us have successfully
passed experimental tests on problem by simulate of modeled with the use of
pseudo-random numbers as well as on real data (of seismic signals etc.) for
which our estimations of the different signals were compared with classical
estimates obtained by the kernel or wavelets estimations method. The precision
of proposed here estimations is better. Our adaptive truncation may be used
also for the signal and image compression.


title: Non-existence of Asymptotically Flat Geons in 2+1 Gravity

abstract:
  Geons, small topological structures that exhibit particle properties such as
charge and angular momentum without the presence of matter sources, have been
extensively discussed in 3+1-dimensional general relativity. Given the recent
renewal of interest in 2+1 gravity, it is natural to ask whether or not the
notion of geons extends to three dimensions. We prove here that, in contrast to
the 3+1-dimensional case, there are no 2+1-dimensional asymptotically flat
solutions of the vacuum Einstein or Einstein-Maxwell equations containing
geons. In contrast, 2+1-dimensional asymptotically anti-de Sitter spacetimes
can indeed contain geons; however, the geons are always hidden behind a single
black hole horizon. We also prove sufficient conditions for the non-existence
of 2+1-dimensional asymptotically flat geon-containing solutions.


title: Graph-based Logic and Sketches

abstract:
  We present the basic ideas of forms (a generalization of Ehresmann's
sketches) and their theories and models, more explicitly than in previous
expositions. Forms provide the ability to specify mathematical structures and
data types in any appropriate category, including many types of structures
(e.g. function spaces) that cannot be specified by sketches. We also outline a
new kind of formal logic (based on graphs instead of strings of symbols) that
gives an intrinsically categorial definition of assertion and proof for each
type of form. This formal logic is new to this monograph. The relationship
between multisorted equational logic and finite product theories is worked out
in detail.


title:
Spectral properties of a partially spin-polarized one-dimensional
  Hubbard/Luttinger superfluid

abstract:
  We calculate the excitation spectra of a spin-polarized Hubbard chain away
from half-filling, using a high-precision momentum-resolved time-dependent
Density Matrix Renormalization Group method. Focusing on the U<0 case, we
present in some detail the single-fermion, pair, density and spin spectra, and
discuss how spin-charge separation is altered for this system. The pair spectra
show a quasi-condensate at a nonzero momentum proportional to the polarization,
as expected for this Fulde-Ferrel-Larkin-Ovchinnikov-like superfluid.


title: Stable solutions of elliptic equations on Riemannian manifolds

abstract:
  This paper is devoted to the study of rigidity properties for special
solutions of nonlinear elliptic partial differential equations on smooth,
boundaryless Riemannian manifolds. As far as stable solutions are concerned, we
derive a new weighted Poincar\'e inequality which allows to prove Liouville
type results and the flatness of the level sets of the solution in dimension 2,
under suitable geometric assumptions on the ambient manifold.


title:
Electrical Switching Dynamics in Circular and Rectangular Ge2Sb2Te5
  Nanopillar Phase Change Memory Devices

abstract:
  We have measured the critical phase change conditions induced by electrical
pulses in Ge2Sb2Te5 nanopillar phase change memory devices by constructing a
comprehensive resistance map as a function of pulse parameters (width,
amplitude and trailing edge). Our measurements reveal that the heating scheme
and the details of the contact geometry play the dominant role in determining
the final phase composition of the device such that a non-uniform heating
scheme promotes partial amorphization/crystallization for a wide range of pulse
parameters enabling multiple resistance levels for data storage applications.
Furthermore we find that fluctuations in the snap-back voltage and set/reset
resistances in repeated switching experiments are related to the details of the
current distribution such that a uniform current injection geometry (i.e.
circular contact) favors more reproducible switching parameters. This shows
that possible geometrical defects in nanoscale phase change memory devices may
play an essential role in the performance of the smallest possible devices
through modification of the exact current distribution in the active
chalcogenide layer. We present a three-dimensional finite element model of the
electro-thermal physics to provide insights into the underlying physical
mechanisms of the switching dynamics as well as to quantitatively account for
the scaling behaviour of the switching currents in both circular and
rectangular contact geometries. The calculated temporal evolution of the heat
distribution within the pulse duration shows distinct features in rectangular
contacts providing evidence for locally hot spots at the sharp corners of the
current injection site due to current crowding effects leading to the observed
behaviour.


title: Finding links and initiators: a graph reconstruction problem

abstract:
  Consider a 0-1 observation matrix M, where rows correspond to entities and
columns correspond to signals; a value of 1 (or 0) in cell (i,j) of M indicates
that signal j has been observed (or not observed) in entity i. Given such a
matrix we study the problem of inferring the underlying directed links between
entities (rows) and finding which entries in the matrix are initiators.
  We formally define this problem and propose an MCMC framework for estimating
the links and the initiators given the matrix of observations M. We also show
how this framework can be extended to incorporate a temporal aspect; instead of
considering a single observation matrix M we consider a sequence of observation
matrices M1,..., Mt over time.
  We show the connection between our problem and several problems studied in
the field of social-network analysis. We apply our method to paleontological
and ecological data and show that our algorithms work well in practice and give
reasonable results.


title: New relationships between Feynman integrals

abstract:
  New types of relationships between Feynman integrals are presented. It is
shown that Feynman integrals satisfy functional equations connecting integrals
with different values of scalar invariants and masses. A method is proposed for
obtaining such relations. The derivation of functional equations for one-loop
propagator- and vertex - type integrals is given. It is shown that a propagator
- type integral can be written as a sum of two integrals with modified scalar
invariants and one propagator massless. The vertex - type integral can be
written as a sum over vertex integrals with all but one propagator massless and
one external momenta squared equal to zero. It is demonstrated that the
functional equations can be used for the analytic continuation of Feynman
integrals to different kinematic domains.


title: D-branes and bivariant K-theory

abstract:
  We review various aspects of the topological classification of D-brane
charges in K-theory, focusing on techniques from geometric K-homology and
Kasparov's KK-theory. The latter formulation enables an elaborate description
of D-brane charge on large classes of noncommutative spaces, and a refined
characterization of open string T-duality in terms of correspondences and
KK-equivalence. The examples of D-branes on noncommutative Riemann surfaces and
in constant H-flux backgrounds are treated in detail. Mathematical
constructions include noncommutative generalizations of Poincare duality and
K-orientation, characteristic classes, and the Riemann-Roch theorem.


title: Crowdsourcing, Attention and Productivity

abstract:
  The tragedy of the digital commons does not prevent the copious voluntary
production of content that one witnesses in the web. We show through an
analysis of a massive data set from \texttt{YouTube} that the productivity
exhibited in crowdsourcing exhibits a strong positive dependence on attention,
measured by the number of downloads. Conversely, a lack of attention leads to a
decrease in the number of videos uploaded and the consequent drop in
productivity, which in many cases asymptotes to no uploads whatsoever.
Moreover, uploaders compare themselves to others when having low productivity
and to themselves when exceeding a threshold.


title: Weakly group-theoretical and solvable fusion categories

abstract:
  We introduce two new classes of fusion categories which are obtained by a
certain procedure from finite groups - weakly group-theoretical categories and
solvable categories. These are fusion categories that are Morita equivalent to
iterated extensions (in the world of fusion categories) of arbitrary,
respectively solvable finite groups. Weakly group-theoretical categories have
integer dimension, and all known fusion categories of integer dimension are
weakly group theoretical. Our main results are that a weakly group-theoretical
category C has the strong Frobenius property (i.e., the dimension of any simple
object in an indecomposable C-module category divides the dimension of C), and
that any fusion category whose dimension has at most two prime divisors is
solvable (a categorical analog of Burnside's theorem for finite groups). This
has powerful applications to classification of fusion categories and
semsisimple Hopf algebras of a given dimension. In particular, we show that any
fusion category of integer dimension <84 is weakly group-theoretical (i.e.
comes from finite group theory), and give a full classification of semisimple
Hopf algebras of dimensions pqr and pq^2, where p,q,r are distinct primes.


title: Simultaneous similarity and triangularization of sets of 2 by 2 matrices

abstract:
  Let $\mathcal{A}=(A_{1},...,A_{n},...)$ be a finite or infinite sequence of
$2\times2$ matrices with entries in an integral domain. We show that, except
for a very special case, $\mathcal{A}$ is (simultaneously) triangularizable if
and only if all pairs $(A_{j},A_{k})$ are triangularizable, for $1\leq
j,k\leq\infty$. We also provide a simple numerical criterion for
triangularization.
  Using constructive methods in invariant theory, we define a map (with the
minimal number of invariants) that distinguishes simultaneous similarity
classes for non-commutative sequences over a field of characteristic $\neq2$.
We also describe canonical forms for sequences of $2\times2$ matrices over
algebraically closed fields, and give a method for finding sequences with a
given set of invariants.


title:
Possible propagation of the Zhang-Rice singlet as a probable Cooper
  channel in the $CuO_2$ planes

abstract:
  The issue of how superconductivity originate in the $CuO_2$ planes believed
to be crucial to understanding the high $T_c$ superconducting cuprates is still
an going debate. In the wake of recent experimental observations of the the
Zhang-Rice singlet (ZRS), its formation and propagation need to be revisited
especially by using a simple approach almost at a phenomenological level.
Within a highly simplified correlated variational approach (HSCVA) in this
paper, a new formation of the ZRS as constituting the ground state of a
single-band t-J model of the $CuO_2$ planes is developed. This formation is
then used to demonstrate how the ZRS can be propagated as a probable Cooper
channel in the $CuO_2$ planes.


title:
Nonclassicality of states and measurements by breaking classical bounds
  on statistics

abstract:
  We derive exceedingly simple practical procedures revealing the quantum
nature of states and measurements by the violation of classical upper bounds on
the statistics of arbitrary measurements. Data analysis is minimum and definite
conclusions are obtained without evaluation of moments, or any other more
sophisticated procedures. These nonclassical tests are independent of other
typical quantum signatures such as sub-Poissonian statistics, quadrature
squeezing, or oscillatory statistics. This approach can be equally well applied
to very diverse situations such as single- and two-mode fields, observables
with continuous and discrete spectra, finite- and infinite-dimensional systems,
and ideal and noisy measurements.


title: Interference Alignment for Line-of-Sight Channels

abstract:
  The fully connected K-user interference channel is studied in a multipath
environment with bandwidth W. We show that when each link consists of D
physical paths, the total spectral efficiency can grow {\it linearly} with K.
This result holds not merely in the limit of large transmit power P, but for
any fixed P, and is therefore a stronger characterization than degrees of
freedom. It is achieved via a form of interference alignment in the time
domain. A caveat of this result is that W must grow with K, a phenomenon we
refer to as {\it bandwidth scaling}. Our insight comes from examining channels
with single path links (D=1), which we refer to as line-of-sight (LOS) links.
For such channels we build a time-indexed interference graph and associate the
communication problem with finding its maximal independent set. This graph has
a stationarity property that we exploit to solve the problem efficiently via
dynamic programming. Additionally, the interference graph enables us to
demonstrate the necessity of bandwidth scaling for any scheme operating over
LOS interference channels. Bandwidth scaling is then shown to also be a
necessary ingredient for interference alignment in the K-user interference
channel.


title:
The radiative transfer at second order: a full treatment of the
  Boltzmann equation with polarization

abstract:
  This article investigates the full Boltzmann equation up to second order in
the cosmological perturbations. Describing the distribution of polarized
radiation by a tensor valued distribution function, we study the gauge
dependence of the distribution function and summarize the construction of the
gauge-invariant distribution function. The Liouville operator which describes
the free streaming of electrons, and the collision term which describes the
scattering of photons on free electrons are computed up to second order.
Finally, the remaining dependence in the direction of the photon momentum is
handled by expanding in projected symmetric trace-free multipoles and also in
the more commonly used normal modes components. The results obtained remain to
be used for computing numerically the contribution in the cosmic microwave
background bispectrum which arises from the evolution of second order
perturbations, in order to disentangle the primordial non-Gaussianity from the
one generated by the subsequent non-linear evolution.


title: Partial Data for the Calderon Problem in Two Dimensions

abstract:
  We show in two dimensions that measuring Dirichlet data for the conductivity
equation on an open subset of the boundary and, roughly speaking, Neumann data
in slightly larger set than the complement uniquely determines the conductivity
on a simply connected domain. The proof is reduced to show a similar result for
the Schr\"odinger equation. Using Carleman estimates with degenerate weights we
construct appropriate complex geometrical optics solutions to prove the
results.


title: Analysis of $\Omega_b^-(bss)$ and $\Omega_c^0(css)$ with QCD sum rules

abstract:
  In this article, we calculate the masses and the pole residues of the
${1/2}^+$ heavy baryons $\Omega_c^0(css)$ and $\Omega_b^-(bss)$ with the QCD
sum rules. The numerical values $M_{\Omega_c^0}=(2.72\pm0.18) \rm{GeV}$ (or
$M_{\Omega_c^0}=(2.71\pm0.18) \rm{GeV}$) and $M_{\Omega_b^-}=(6.13\pm0.12)
\rm{GeV}$ (or $M_{\Omega_b^-}=(6.18\pm0.13) \rm{GeV}$) are in good agreement
with the experimental data.


title: Gravitational wave recoil in Robinson-Trautman spacetimes

abstract:
  We consider the gravitational recoil due to non-reflection-symmetric
gravitational wave emission in the context of axisymmetric Robinson-Trautman
spacetimes. We show that regular initial data evolve generically into a final
configuration corresponding to a Schwarzschild black-hole moving with constant
speed. For the case of (reflection-)symmetric initial configurations, the mass
of the remnant black-hole and the total energy radiated away are completely
determined by the initial data, allowing us to obtain analytical expressions
for some recent numerical results that have been appeared in the literature.
Moreover, by using the Galerkin spectral method to analyze the non-linear
regime of the Robinson-Trautman equations, we show that the recoil velocity can
be estimated with good accuracy from some asymmetry measures (namely the first
odd moments) of the initial data. The extension for the non-axisymmetric case
and the implications of our results for realistic situations involving head-on
collision of two black holes are also discussed.


title: Motional Coherence in Fluid Phospholipid Membranes

abstract:
  We report a high energy-resolution neutron backscattering study, combined
with in-situ diffraction, to investigate slow molecular motions on nanosecond
time scales in the fluid phase of phospholipid bilayers of
1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine (DMPC) and DMPC/40% cholesterol
(wt/wt). A cooperative structural relaxation process was observed. From the
in-plane scattering vector dependence of the relaxation rates in hydrogenated
and deuterated samples, combined with results from a 0.1 microsecond long all
atom molecular dynamics simulation, it is concluded that correlated dynamics in
lipid membranes occurs over several lipid distances, spanning a time interval
from pico- to nanoseconds.


title:
Dynamics of polymers in elongational flow investigated by inelastic
  neutron scattering

abstract:
  The nanoscale fluctuation dynamics of semi dilute high molecular weight
polymer solutions of Polyethylenoxide (PEO) in D2O under non-equilibrium flow
conditions were studied by the neutron spin-echo technique. The sample cell was
in contraction flow geometry and provided a pressure driven flow with a high
elongational component that stretched the polymers most efficiently. The
experiments suggest that the mobility on the scale of a few monomers,
comparable to the Kuhn segment length, becomes highly anisotropic and is
enhanced perpendicular to the flow direction. Diffraction data show a weak
structural correlation along the chains on a length scale of about 17
Angstroems, which might be related to the Kuhn length in this system.


title: Active motions of Brownian particles in a generalized energy-depot model

abstract:
  We present a generalized energy-depot model in which the conversion rate of
the internal energy into motion can be dependent on the position and the
velocity of a particle. When the conversion rate is a general function of the
velocity, the active particle exhibits diverse patterns of motion including a
braking mechanism and a stepping motion. The phase trajectories of the motion
are investigated in a systematic way. With a particular form of the conversion
rate dependent on the position and velocity, the particle shows a spontaneous
oscillation characterizing a negative stiffness. These types of active
behaviors are compared with the similar phenomena observed in biology such as
the stepping motion of molecular motors and the amplification in hearing
mechanism. Hence, our model can provide a generic understanding of the active
motion related to the energy conversion and also a new control mechanism for
nano-robots. We also investigate the noise effect, especially on the stepping
motion and observe the random walk-like behavior as expected.


title: Integrally Closed Ideals on Log Terminal Surfaces are Multiplier Ideals

abstract:
  We show that all integrally closed ideals on log terminal surfaces are
multiplier ideals by extending an existing proof for smooth surfaces.


title:
Kinetostatic Performance of a Planar Parallel Mechanism with Variable
  Actuation

abstract:
  This paper deals with a new planar parallel mechanism with variable actuation
and its kinetostatic performance. A drawback of parallel mechanisms is the non
homogeneity of kinetostatic performance within their workspace. The common
approach to solve this problem is the introduction of actuation redundancy,
that involves force control algorithms. Another approach, highlighted in this
paper, is to select the actuated joint in each limb with regard to the pose of
the end-effector. First, the architecture of the mechanism and two kinetostatic
performance indices are described. Then, the actuating modes of the mechanism
are compared.


title:
Simultaneous Triggered Collapse of the Presolar Dense Cloud Core and
  Injection of Short-Lived Radioisotopes by a Supernova Shock Wave

abstract:
  Cosmochemical evidence for the existence of short-lived radioisotopes (SLRI)
such as $^{26}$Al and $^{60}$Fe at the time of the formation of primitive
meteorites requires that these isotopes were synthesized in a massive star and
then incorporated into chondrites within $\sim 10^6$ yr. A supernova shock wave
has long been hypothesized to have transported the SLRI to the presolar dense
cloud core, triggered cloud collapse, and injected the isotopes. Previous
numerical calculations have shown that this scenario is plausible when the
shock wave and dense cloud core are assumed to be isothermal at $\sim 10$ K,
but not when compressional heating to $\sim 1000$ K is assumed. We show here
for the first time that when calculated with the FLASH2.5 adaptive mesh
refinement (AMR) hydrodynamics code, a 20 km/sec shock wave can indeed trigger
the collapse of a 1 $M_\odot$ cloud while simultaneously injecting shock wave
isotopes into the collapsing cloud, provided that cooling by molecular species
such as H$_2$O, CO$_2$, and H$_2$ is included. These calculations imply that
the supernova trigger hypothesis is the most likely mechanism for delivering
the SLRI present during the formation of the solar system.


title: Groups with the same cohomology as their pro-$p$ completions

abstract:
  For any prime $p$ and group $G$, denote the pro-$p$ completion of $G$ by
$\hat{G}^p$. Let $\mathcal{C}$ be the class of all groups $G$ such that, for
each natural number $n$ and prime number $p$, $H^n(\hat{G^p},\mathbb Z/p)\cong
H^n(G, \mathbb Z/p)$, where $\mathbb Z/p$ is viewed as a discrete, trivial
$\hat{G}^p$-module. In this article we identify certain kinds of groups that
lie in $\mathcal{C}$. In particular, we show that right-angled Artin groups are
in $\mathcal{C}$ and that this class also contains some special types of free
products with amalgamation.


title: Commutators on $\ell_1$

abstract:
  The main result is that the commutators on $\ell_1$ are the operators not of
the form $\lambda I + K$ with $\lambda\neq 0$ and $K$ compact. We generalize
Apostol's technique (1972, Rev. Roum. Math. Appl. 17, 1513 - 1534) to obtain
this result and use this generalization to obtain partial results about the
commutators on spaces $\X$ which can be represented as $\displaystyle \X\simeq
(\bigoplus_{i=0}^{\infty} \X)_{p}$ for some $1\leq p<\infty$ or $p=0$. In
particular, it is shown that every compact operator on $L_1$ is a commutator. A
characterization of the commutators on
$\ell_{p_1}\oplus\ell_{p_2}\oplus...\oplus\ell_{p_n}$ is given. We also show
that strictly singular operators on $\ell_{\infty}$ are commutators.


title: Fermion states on domain wall junctions and the flavor number

abstract:
  In this paper we address the problem of localizing fermion states on stable
domain walls junctions. The study focus on the consequences of intersecting six
independent 8d domain walls to form 4d junctions in a ten-dimensional
spacetime. This is related to the mechanism of relaxing to three space
dimensions through the formation of domain wall junctions. The model is based
on six bulk real scalar fields, the phi-4 model in its broken phase, the
prototype of the Higgs field, and is such that the fermion and scalar modes
bound to the domain walls are the zero mode and a single massive bound state,
which can be regarded as a two level system, at least at sufficiently low
energy. Inside the junction, we use the fact that some states are statistically
more favored to address the possibility of constraining the flavor number of
the elementary fermions.


title: Numerical Solution of Multiple Nonlinear Volterra Integral Equations

abstract:
  We analyze a discretization method for solving nonlinear integral equations
that contain multiple integrals. These equations include integral equations
with a Volterra series, instead of a single integral term, on one side of the
equation. We prove existence and uniqueness of solutions, and convergence and
estimates of the order of convergence for the numerical methods of solution.


title: Quantum dimer models and exotic orders

abstract:
  We discuss how quantum dimer models may be used to provide "proofs of
principle" for the existence of exotic magnetic phases in quantum spin systems.


title: Quantum dimer models

abstract:
  These lecture notes aim to provide a self-contained, pedagogical introduction
to the physics of local constraints, fractionalisation and topological liquids
organised around the Rokhsar-Kivelson quantum dimer model. Topics and phenomena
covered include emergent photons, SU(2) invariant spin liquids, valence-bond
solids and Cantor deconfinement, along with an elementary introduction to the
underlying theoretical models and methods.


title:
Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II.
  Determination of, and results for, the pion form factor

abstract:
  The charged pion form factor, Fpi(Q^2), is an important quantity which can be
used to advance our knowledge of hadronic structure. However, the extraction of
Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is
inherently model dependent. Therefore, a detailed description of the extraction
of the charged pion form factor from electroproduction data obtained recently
at Jefferson Lab is presented, with particular focus given to the dominant
uncertainties in this procedure. Results for Fpi are presented for
Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically
below the monopole parameterization that describes the low Q^2 data used to
determine the pion charge radius. The pion form factor can be calculated in a
wide variety of theoretical approaches, and the experimental results are
compared to a number of calculations. This comparison is helpful in
understanding the role of soft versus hard contributions to hadronic structure
in the intermediate Q^2 regime.


title: Implementation of many-qubit Grover search with trapped ultracold ions

abstract:
  We propose a potentially practical scheme for realization of an n-qubit (n>2)
conditional phase flip (CPF) gate and implementation of Grover search algorithm
in the ion-trap system. We demonstrate both analytically and numerically that,
our scheme could be achieved efficiently to find a marked state with high
fidelity and high success probability. We also show the merits of the proposal
that the increase of the ion number can improve the fidelity and the success
probability of the CPF gate. The required operations for Grover search are very
close to the capabilities of current ion-trap techniques.


title:
Yukawa Corrections to gamma gamma --> b\bar{b} in the Topcolor Assisted
  Technicolor Models

abstract:
  We study the Yukawa corrections to the gamma gamma --> b\bar{b} corss section
in the topcolor assisted technicolor models at the photon-photon colliders. We
find that, for the favorable parameters, the relative corrections from pseudo
Goldstone bosons give out a 3.2%--5.9% decrement of the cross section from the
tree level when \sqrt{s}=500 GeV, the contributions from new extended
technicolor gauge bosons Z* and colored gauge bosons B are negligibly small,
and the relative correction arising from new color-singlet heavy gauge boson Z'
is less than -3.2%. Therefore, the total relative corrections are significantly
larger than the corresponding corrections in the standard model, the general
two Higgs doublet model and the minimal supersymmetric standard model. Since
these corrections are obvious for the International Linear Colliders, the
process gamma gamma --> b\bar{b} is really interesting in testing the standard
model and searching for the signs of technicolor.


title:
Theoretical Analysis of Resonant Inelastic X-Ray Scattering Spectra in
  LaMnO3

abstract:
  We analyze the resonant inelastic x-ray scattering (RIXS) spectra at the K
edge of Mn in the antiferromagnetic insulating manganite LaMnO3. We make use of
the Keldysh-type Green-function formalism, in which the RIXS intensity is
described by a product of an incident-photon-dependent factor and a
density-density correlation function in the 3d states. We calculate the former
factor using the 4p density of states given by an ab initio band structure
calculation and the latter using a multi-orbital tight-binding model. The
ground state of the model Hamiltonian is evaluated within the Hartree-Fock
approximation. Correlation effects are treated within the random phase
approximation (RPA). We obtain the RIXS intensity in a wide range of
energy-loss 2-15 eV. The spectral shape is strongly modified by the RPA
correlation, showing good agreement with the experiments. The
incident-photon-energy dependence also agrees well with the experiments. The
present mechanism that the RIXS spectra arise from band-to-band transitions to
screen the core-hole potential is quite different from the orbiton picture
previously proposed, enabling a comprehensive understanding of the RIXS
spectra.


title:
Bell-state preparation for fullerene based electron spins in distant
  peapod nanotubes

abstract:
  We propose a potentially practical scheme, in combination with the Bell-state
analyzer [Zhang et al., Phys. Rev. A 73, 014301 (2006)], to generate Bell
states for two electron spins confined, respectively, in two distant
fullerenes. To this end, we consider the endohedral fullerenes staying in
single walled carbon nanotubes (SWCNTs) and employ auxiliary mobile electrons
and selective microwave pulses. The application and the experimental
feasibility of our scheme are discussed.


title: On the acceleration of Ultra-High-Energy Cosmic Rays

abstract:
  Ultra High Energy Cosmic Rays (UHECRs) hit the Earth's atmosphere with
energies exceeding $10^{18}$ eV. This is the same energy as carried by a tennis
ball moving at 100 km/h, but concentrated on a sub-atomic particle. UHECRs are
so rare (the flux of particles with $E > 10^{20}$ eV is 0.5/km$^2$/century)
that only a few such particles have been detected over the past 50 years.
Recently, the HiRes and Auger experiments have reported the discovery of a
high-energy cut-off in the UHECR spectrum, and Auger has found an apparent
clustering of the highest energy events towards nearby active galactic nuclei.
Consensus is building that the highest energy particles are accelerated within
the radio-bright lobes of these objects, but it remains unclear how this
actually happens, and whether the cut-off is due to propagation effects or
reflects an intrinsically physical limitation of the acceleration process. The
low event statistics presently allows for many different plausible models;
nevertheless observations are beginning to impose strong constraints on them.
These observations have also motivated suggestions that new physics may be
implicated. We present a review of the key theoretical and observational issues
related to the processes of propagation and acceleration of UHECRs and proposed
solutions.


title:
Laser-Cluster-Interaction in a Nanoplasma-Model with Inclusion of
  Lowered Ionization Energies

abstract:
  The interaction of intense laser fields with silver and argon clusters is
investigated theoretically using a modified nanoplasma model. Single pulse and
double pulse excitations are considered. The influence of the dense cluster
environment on the inner ionization processes is studied including the lowering
of the ionization energies. There are considerable changes in the dynamics of
the laser-cluster interaction. Especially, for silver clusters, the lowering of
the ionization energies leads to increased yields of highly charged ions.


title: Some Enigmatic Aspects of the Early Universe III

abstract:
  In the previous parts of the discussion on the same topic, various aspects of
the very early universe were discussed. We discussed how inclusion of large
dark energy term compensates for the net gravity. Here the discussion is taken
further including the effects of charge, magnetic fields and rotation. The role
of large extra dimensions under the extreme initial conditions is discussed and
possible connection with the cyclic brane theory is explored. We constrain
various cosmic quantities like the net charge, number density of magnetic
monopoles, primordial magnetic fields, size of the extra dimensions,etc.


title: Non-Gibrat's law in the middle scale region

abstract:
  By using numerical simulation, we confirm that Takayasu--Sato--Takayasu (TST)
model which leads Pareto's law satisfies the detailed balance under Gibrat's
law. In the simulation, we take an exponential tent-shaped function as the
growth rate distribution. We also numerically confirm the reflection law
equivalent to the equation which gives the Pareto index $\mu$ in TST model.
Moreover, we extend the model modifying the stochastic coefficient under a
Non-Gibrat's law. In this model, the detailed balance is also numerically
observed. The resultant pdf is power-law in the large scale Gibrat's law
region, and is the log-normal distribution in the middle scale Non-Gibrat's
one. These are accurately confirmed in the numerical simulation.


title: Toeplitz-composition C*-algebras for certain finite Blaschke products

abstract:
  Let R be a finite Blaschke product of degree at least two with R(0)=0. Then
there exists a relation between the associated composition operator C_R on the
Hardy space and the C*-algebra associated with the complex dynamical system on
the Julia set of R. We study the C*-algebra generated by both the composition
operator C_R and the Toeplitz operator T_z to show that the quotient algebra by
the ideal of the compact operators is isomorphic to the C*-algebra associated
with the complex dynamical system, which is simple and purely infinite.


title:
Local phase space control and interplay of classical and quantum effects
  in dissociation of a driven Morse oscillator

abstract:
  This work explores the possibility of controlling the dissociation of a
monochromatically driven one-dimensional Morse oscillator by recreating
barriers, in the form of invariant tori with irrational winding ratios, at
specific locations in the phase space. The control algorithm proposed by Huang
{\it et al.} (Phys. Rev. A {\bf 74}, 053408 (2006)) is used to obtain an
analytic expression for the control field. We show that the control term,
approximated as an additional weaker field, is efficient in recreating the
desired tori and suppresses the classical as well as the quantum dissociation.
However, in the case when the field frequency is tuned close to a two-photon
resonance the local barriers are not effective in suppressing the dissociation.
We establish that in the on-resonant case quantum dissociation primarily occurs
via resonance-assisted tunneling and controlling the quantum dynamics requires
a local perturbation of the specific nonlinear resonance in the underlying
phase space.


title: On rigid Hirzebruch genera

abstract:
  The classical multiplicative (Hirzebruch) genera of manifolds have the
wonderful property which is called rigidity. Rigidity of a genus h means that
if a compact connected Lie group G acts on a manifold X, then the equivariant
genus h^G(X) is independent on G, i.e. h^G(X)=h(X). In this paper we are
considering the rigidity problem for complex manifolds. In particular, we are
proving that a genus is rigid if and only if it is a generalized Todd genus.


title: Flavor Symmetry Breaking and Vacuum Alignment on Orbifolds

abstract:
  Flavor symmetry has been widely studied for figuring out the masses and
mixing angles of standard-model fermions. In this paper we present a framework
for handling flavor symmetry breaking where the symmetry breaking is triggered
by boundary conditions of scalar fields in extra-dimensional space. The
alignment of scalar expectation values is achieved without referring to any
details of scalar potential and its minimization procedure. As applications to
non-abelian discrete flavor symmetries, illustrative lepton mass models are
constructed where the S3 and A4 flavor symmetries are broken down to the
directions leading to the tri-bimaximal form of lepton mixing and realistic
mass patterns.


title: Metastable supersymmetry breaking vacua from conformal dynamics

abstract:
  We study the scenario that conformal dynamics leads to metastable
supersymmetry breaking vacua. At a high energy scale, the superpotential is not
R-symmetric, and has a supersymmetric minimum. However, conformal dynamics
suppresses several operators along renormalization group flow toward the
infrared fixed point. Then we can find an approximately R-symmetric
superpotential, which has a metastable supersymmetry breaking vacuum, and the
supersymmetric vacuum moves far away from the metastable supersymmetry breaking
vacuum. We show a 4D simple model. Furthermore, we can construct 5D models with
the same behavior, because of the AdS/CFT dual.


title: Some Notes on Standard Borel and Related Spaces

abstract:
  These notes give an elementary approach to parts of the theory of standard
Borel and analytic spaces.


title:
Single domain magnetic helicity and triangular chirality in structurally
  enantiopure Ba3NbFe3Si2O14

abstract:
  A novel doubly chiral magnetic order is found out in the structurally chiral
langasite compound Ba$_3$NbFe$_3$Si$_2$O$_{14}$. The magnetic moments are
distributed over planar frustrated triangular lattices of triangle units. On
each of these they form the same triangular configuration. This ferro-chiral
arrangement is helically modulated from plane to plane. Unpolarized neutron
scattering on a single crystal associated with spherical neutron polarimetry
proved that a single triangular chirality together with a single helicity is
stabilized in an enantiopure crystal. A mean field analysis allows discerning
the relevance on this selection of a twist in the plane to plane
supersuperexchange paths.


title: Desingularization of some moduli scheme of stable sheaves on a surface

abstract:
  Let $X$ be a nonsingular projective surface over an algebraically closed
field with characteristic zero, and $H_-$ and $H_+$ ample line bundles on $X$
separated by only one wall of type $(c_1,c_2)$. Suppose the moduli scheme
$M(H_-)$ of rank-two $H_-$-stable sheaves with Chern classes $(c_1,c_2)$ is
non-singular. We shall construct a desingularization of $M(H_+)$ by using
$M(H_-)$. As an application, we consider whether singularities of $M(H_+)$ are
terminal or not when $X$ is ruled or elliptic.


title: Global Disk Oscillations in Binary Be Stars

abstract:
  We study the effects of the tidal interaction with the companion, via orbital
separation and binary mass ratio, on the global one-armed oscillation modes in
disks around binary Be stars. Our model takes into account the
three-dimensional effect that contributes to the mode confinement, which was
recently found by Ogilvie(2008). We find that the one-armed oscillations are
well confined in systems with disks larger than a few tens of stellar radii. In
such systems, the oscillation period depends little on the binary parameters.
On the other hand, in systems with smaller disks, where the mode confinement is
incomplete, the oscillation period increases with increasing orbital separation
and/or decreasing binary mass ratio. The eigenmode is insensitive to the
spectral type of the central star. Our results suggest that the dependence of
V/R oscillation period on the orbital separation and binary mass ratio should
be observed only in short period binary systems, and that, for systems with a
similar orbital period, those with higher mass ratios will show shorter V/R
variations.


title: Markov invariants and the isotropy subgroup of a quartet tree

abstract:
  The purpose of this article is to show how the isotropy subgroup of leaf
permutations on binary trees can be used to systematically identify
tree-informative invariants relevant to models of phylogenetic evolution. In
the quartet case, we give an explicit construction of the full set of
representations and describe their properties. We apply these results directly
to Markov invariants, thereby extending previous theoretical results by
systematically identifying linear combinations that vanish for a given quartet.
We also note that the theory is fully generalizable to arbitrary trees and is
equally applicable to the related case of phylogenetic invariants. All results
follow from elementary consideration of the representation theory of finite
groups.


title: Linear Response for Confined Particles

abstract:
  The dynamics of fluctuations is considered for electrons near a positive ion
or for charges in a confining trap. The stationary nonuniform equilibrium
densities are discussed and contrasted. The linear response function for small
perturbations of this nonuniform state is calculated from a linear Markov
kinetic theory whose generator for the dynamics is exact in the short time
limit. The kinetic equation is solved in terms of an effective mean field
single particle dynamics determined by the local density and dynamical
screening by a dielectric function for the non-uniform system. The
autocorrelation function for the total force on the charges is discussed.


title:
Lepton Flavor Violating tau --> 3mu Decay in Type-III Two Higgs Doublet
  Model

abstract:
  We study the current structure of the lepton flavor violating $\tau\to3\mu$
decay in Type-III 2HDM. This model has many coupling constants which affect
this decay. We find that each coupling constant corresponds to the different
final-state momenta distribution and vice versa. Using this fact, we suggest
how to determine the current structure. We also find the upper limit
$|\eta_{23}^E\eta_{22}^E|<0.00022$ in the case that all Higgs bosons except for
the lighter CP even neutral one $h^0$ are decoupled, $M_{h^0}=115$GeV and
$\cos\beta=1/\sqrt{2}$. The observable difference between the MSSM and type-III
2HDM is also discussed.


title:
AKARI Near Infrared Spectroscopy: Detection of H2O and CO2 Ices toward
  Young Stellar Objects in the Large Magellanic Cloud

abstract:
  We present the first results of AKARI Infrared Camera near-infrared spec-
troscopic survey of the Large Magellanic Cloud (LMC). We detected absorption
features of the H2O ice 3.05 um and the CO2 ice 4.27 um stretching mode toward
seven massive young stellar objects (YSOs). These samples are for the first
time spectroscopically confirmed to be YSOs. We used a curve-of-growth method
to evaluate the column densities of the ices and derived the CO2/H2O ratio to
be 0.45 pm 0.17. This is clearly higher than that seen in Galactic massive YSOs
(0.17 pm 0.03). We suggest that the strong ultraviolet radiation field and/or
the high dust temperature in the LMC may be responsible for the observed high
CO2 ice abundance.


title: Kinematics of geodesic flows in stringy black hole backgrounds

abstract:
  We study the kinematics of timelike geodesic congruences in two and four
dimensions in spacetime geometries representing stringy black holes. The
Raychaudhuri equations for the kinematical quantities (namely, expansion, shear
and rotation) characterising such geodesic flows are written down and
subsequently solved analytically (in two dimensions) and numerically (in four
dimensions) for specific geodesics flows. We compare between geodesic flows in
dual (electric and magnetic) stringy black hole backgrounds in four dimensions,
by showing the differences that arise in the corresponding evolutions of the
kinematic variables. The crucial role of initial conditions and the spacetime
curvature on the evolution of the kinematical variables is illustrated. Some
novel general conclusions on geodesic focusing are obtained from the analytical
and numerical findings. We also propose new quantifiers in terms of (a) the
time (affine parameter) of approach to a singularity and (b) the location of
extrema in the functional evolution of the kinematic variables, which may be
used to distinguish between flows in different geometries. In summary, our
quantitative findings bring out hitherto unknown features of the kinematics of
geodesic flows, which, otherwise, would have remained overlooked, if we
confined ourselves to only a qualitative analysis.


title:
Finite-temperature chiral condensate and low-lying Dirac eigenvalues in
  quenched SU(2) lattice gauge theory

abstract:
  The spectrum of low-lying eigenvalues of overlap Dirac operator in quenched
SU(2) lattice gauge theory with tadpole-improved Symanzik action is studied at
finite temperatures in the vicinity of the confinement-deconfinement phase
transition defined by the expectation value of the Polyakov line. The value of
the chiral condensate obtained from the Banks-Casher relation is found to drop
down rapidly at T = Tc, though not going to zero. At Tc' = 1.5 Tc = 480 MeV the
chiral condensate decreases rapidly one again and becomes either very small or
zero. At T < Tc the distributions of small eigenvalues are universal and are
well described by chiral orthogonal ensemble of random matrices. In the
temperature range above Tc where both the chiral condensate and the expectation
value of the Polyakov line are nonzero the distributions of small eigenvalues
are not universal. Here the eigenvalue spectrum is better described by a
phenomenological model of dilute instanton - anti-instanton gas.


title: Lifting Galois representations over arbitrary number fields

abstract:
  It is proved that every two-dimensional residual Galois representation of the
absolute Galois group of an arbitrary number field lifts to a characteristic
zero $p$-adic representation, if local lifting problems at places above $p$ are
unobstructed.


title:
Luminous Blue Variable Stars In The Two Extremely Metal-Deficient Blue
  Compact Dwarf Galaxies DDO 68 and PHL 293B

abstract:
  We present photometric and spectroscopic observations of two luminous blue
variable (LBV) stars in two extremely metal-deficient blue compact dwarf (BCD)
galaxies, DDO 68 with 12+logO/H = 7.15 and PHL 293B with 12+logO/H = 7.72.
These two BCDs are the lowest-metallicity galaxies where LBV stars have been
detected, allowing to study the LBV phenomenon in the extremely low metallicity
regime, and shedding light of the evolution of the first generation of massive
stars born from primordial gas. We find that the strong outburst of the LBV
star in DDO 68 occurred sometime between February 2007 and January 2008. We
have compared the properties of the broad line emission in low-metallicity LBVs
with those in higher metallicity LBVs. We find that, for the LBV star in DDO
68, broad emission with a P Cygni profile is seen in both H and He I emission
lines. On the other hand, for the LBV star in PHL 293B, P Cygni profiles are
detected only in H lines. For both LBVs, no heavy element emission line such as
Fe II was detected. The Halpha luminosities of LBV stars in both galaxies are
comparable to the one obtained for the LBV star in NGC 2363 (Mrk 71) which has
a higher metallicity 12+logO/H = 7.89. On the other hand, the terminal
velocities of the stellar winds in both low-metallicity LBVs are high, ~800
km/s, a factor of ~4 higher than the terminal velocities of the winds in
high-metallicity LBVs. This suggests that stellar winds at low metallicity are
driven by a different mechanism than the one operating in high-metallicity
winds.


title: Ill-Contact Effects of d-Orbital Channels in Nanometer-Scale Conductor

abstract:
  Electronic current in a nanometer-size rod is theoretically investigated by
an eigen-channel decomposition method in nonequilibrium Green's function
formalism. Physical properties, such as the local density of electrons and
local current, are decomposed into contributions of eigen-channels. We observe
that the evanescent modes and nonlinear conductance are enhanced in d-orbital
systems, and the structure of the transmission function, local current density,
and penetration depth are discussed. The two effects of the ill-contact at
electrodes in d-orbital systems, evanescent modes and the nonlinearity of
conductance, are regarded as originating in the peak structure of the
transmission function of eigen-channels in the energy region between chemical
potentials of left and right lead wires.


title: Characteristic length of an AdS/CFT superconductor

abstract:
  We investigate in more detail the holographic model of a superconductor
recently found by Hartnoll, Herzog, and Horowitz [Phys. Rev. Lett. 101,
031601], which is constructed from a condensate of a charged scalar field in
AdS_4-Schwarzschild background. By analytically studying the perturbation of
the gravitational system near the critical temperature T_c, we obtain the
superconducting coherence length proportional to 1/\sqrt{1-T/T_c} via AdS/CFT
correspondence. By adding a small external homogeneous magnetic field to the
system, we find that a stationary diamagnetic current proportional to the
square of the order parameter is induced by the magnetic field. These results
agree with Ginzburg-Landau theory and strongly support the idea that a
superconductor can be described by a charged scalar field on a black hole via
AdS/CFT duality.


title: Critical surface in hot and dense QCD with the vector interaction

abstract:
  We discuss the chiral phase transition of hot and dense quark matter. We
illustrate that the first-order phase transition is generally favored at high
baryon density and the repulsive vector-vector interaction weakens the
first-order phase transition. We use the Nambu--Jona-Lasinio model with the
Polyakov loop coupling for concreteness. We locate the QCD critical surface on
the quark mass plane for various values of the vector coupling constant. We
find that, with increasing quark chemical potential, the first-order region in
the quark mass plane could shrink for sufficiently large vector coupling. This
may be a possible explanation for the recent lattice QCD results by de Forcrand
and Philipsen.


title: Undetermined states: how to find them and their applications

abstract:
  We investigate the undetermined sets consisting of two-level, multi-partite
pure quantum states, whose reduced density matrices give absolutely no
information of their original states. Two approached of finding these quantum
states are proposed. One is to establish the relation between codewords of the
stabilizer quantum error correction codes (SQECCs) and the undetermined states.
The other is to study the local complementation rules of the graph states. As
an application, the undetermined states can be exploited in the quantum secret
sharing scheme. The security is guaranteed by their undetermineness.


title:
The Spitzer View of Low-Metallicity Star Formation: II. Mrk 996, a Blue
  Compact Dwarf Galaxy with an Extremely Dense Nucleus

abstract:
  (abridged) We present new Spitzer, UKIRT and MMT observations of the blue
compact dwarf galaxy (BCD) Mrk 996, with an oxygen abundance of
12+log(O/H)=8.0. This galaxy has the peculiarity of possessing an
extraordinarily dense nuclear star-forming region, with a central density of
~10^6 cm^{-3}. The nuclear region of Mrk 996 is characterized by several
unusual properties: a very red color J-K = 1.8, broad and narrow emission-line
components, and ionizing radiation as hard as 54.9 eV, as implied by the
presence of the OIV 25.89 micron line. The nucleus is located within an
exponential disk with colors consistent with a single stellar population of age
>1 Gyr. The infrared morphology of Mrk 996 changes with wavelength. The IRS
spectrum shows strong narrow Polycyclic Aromatic Hydrocarbon (PAH) emission,
with narrow line widths and equivalent widths that are high for the metallicity
of Mrk 996. Gaseous nebular fine-structure lines are also seen. A CLOUDY model
requires that they originate in two distinct HII regions: a very dense HII
region of radius ~580 pc with densities declining from ~10^6 at the center to a
few hundreds cm^{-3} at the outer radius, where most of the optical lines
arise; and a HII region with a density of ~300 cm^{-3} that is hidden in the
optical but seen in the MIR. We suggest that the infrared lines arise mainly in
the optically obscured HII region while they are strongly suppressed by
collisional deexcitation in the optically visible one. The hard ionizing
radiation needed to account for the OIV 25.89 micron line is most likely due to
fast radiative shocks propagating in an interstellar medium. A hidden
population of Wolf-Rayet stars of type WNE-w or a hidden AGN as sources of hard
ionizing radiation are less likely possibilities.


title: Supervised Dictionary Learning

abstract:
  It is now well established that sparse signal models are well suited to
restoration tasks and can effectively be learned from audio, image, and video
data. Recent research has been aimed at learning discriminative sparse models
instead of purely reconstructive ones. This paper proposes a new step in that
direction, with a novel sparse representation for signals belonging to
different classes in terms of a shared dictionary and multiple class-decision
functions. The linear variant of the proposed model admits a simple
probabilistic interpretation, while its most general variant admits an
interpretation in terms of kernels. An optimization framework for learning all
the components of the proposed model is presented, along with experimental
results on standard handwritten digit and texture classification tasks.


title:
Single-crystal growth of the ternary BaFe$_2$As$_2$ phase using the
  vertical Bridgman technique

abstract:
  Ternary Ba-Fe-As system has been studied to determine a primary
solidification field of the BaFe$_2$As$_2$ phase. We found that the
BaFe$_2$As$_2$ phase most likely melts congruently and primarily solidifies
either in the FeAs excess or Ba$_{x}$As$_{100-x}$ excess liquid. Knowing the
primary solidification field, we have performed the vertical Bridgman growth
using the starting liquid composition of Ba$_{15}$Fe$_{42.5}$As$_{42.5}$. Large
single crystals of the typical size 10x4x2 mm$^3$ were obtained and their
quality was confirmed by X-ray Laue and neutron diffraction.


title: Present Status of the Muon Anomalous Magnetic Moment

abstract:
  These pages, based on my talk at the Montpellier 14th International
Conference in QCD, provide us with a short update of the Standard Model
contributions to the Muon Anomalous Magnetic Moment.


title: Resonant Casimir--Polder forces in planar meta-materials

abstract:
  We study the resonant Casimir--Polder potential of an excited atom near a
half space containing magneto-electric meta-material of various kinds on the
basis of macroscopic quantum electrodynamics. Analytical results are obtained
in the nonretarded and retarded distance regimes and numerical examples are
given. We compare our findings with the potential of an excited atom near a
left-handed superlens.


title:
The Lee-Yang and P\'olya-Schur Programs. II. Theory of Stable
  Polynomials and Applications

abstract:
  In the first part of this series we characterized all linear operators on
spaces of multivariate polynomials preserving the property of being
non-vanishing in products of open circular domains. For such sets this
completes the multivariate generalization of the classification program
initiated by P\'olya-Schur for univariate real polynomials. We build on these
classification theorems to develop here a theory of multivariate stable
polynomials. Applications and examples show that this theory provides a natural
framework for dealing in a uniform way with Lee-Yang type problems in
statistical mechanics, combinatorics, and geometric function theory in one or
several variables. In particular, we answer a question of Hinkkanen on
multivariate apolarity.

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


title:
Large-Scale Alignments of Quasar Polarization Vectors: Evidence at
  Cosmological Scales for Very Light Pseudoscalar Particles Mixing with
  Photons?

abstract:
  Based on a sample of 355 quasars with significant optical polarization, we
found that quasar polarization vectors are not randomly oriented over the sky
as naturally expected. The probability that the observed distribution of
polarization angles is due to chance is lower than 0.1%. The polarization
vectors of the light from quasars are aligned although the sources span huge
regions of the sky (~ 1 Gpc). Groups of quasars located along similar lines of
sight but at different redshifts (typically z ~ 0.5 and z ~ 1.5) are
characterized by different preferred directions of polarization. These
characteristics make the observed alignment effect difficult to explain in
terms of a local contamination by interstellar polarization in our Galaxy.
Interpreted in terms of a cosmological-size effect, we show that the dichroism
and birefringence predicted by a mixing between photons and very light
pseudoscalar particles within a magnetic field can qualitatively reproduce the
observations. We find that circular polarization measurements could help
constrain this mechanism.


title:
Magnetic Field Configuration at the Galactic Center Investigated by Wide
  Field Near-Infrared Polarimetry

abstract:
  We present a polarimetric map of a 20'x20' area toward the Galactic center.
The polarization of point sources has been measured in the J, H, and Ks bands
using the near-infrared polarimetric camera SIRPOL on the 1.4 m telescope IRSF.
One percent or better accuracy of polarization degree is achieved for sources
with J<14.5, H<13.5, and Ks<12.0. Comparing the Stokes parameters between high
extinction stars and relatively low extinction ones, we have obtained a
polarization originating from magnetically aligned dust grains at the central
region of our Galaxy of at most 1-2 kpc. The distribution of the position
angles shows a peak at about 20 deg, nearly parallel to the Galactic plane,
suggesting a toroidal magnetic configuration. The derived direction of the
magnetic field is in good agreement with that obtained from
far-infrared/submillimeter observations, which detect polarized thermal
emission from dust in the molecular clouds at the Galactic center. Our results
show that by subtracting foreground components, near-infrared polarimetry
allows investigation of the magnetic field structure "at" the Galactic center.


title: Simple equation of state for hard disks on the hyperbolic plane

abstract:
  A simple equation of state for hard disks on the hyperbolic plane is
proposed. It yields the exact second virial coefficient and contains a pole at
the highest possible packing. A comparison with another very recent theoretical
proposal and simulation data is presented.


title:
A Distributed Algorithm for Fair and Efficient User-Network Association
  in Multi-Technology Wireless Networks

abstract:
  Recent mobile equipment (as well as the norm IEEE 802.21) now offers the
possibility for users to switch from one technology to another (vertical
handover). This allows flexibility in resource assignments and, consequently,
increases the potential throughput allocated to each user. In this paper, we
design a fully distributed algorithm based on trial and error mechanisms that
exploits the benefits of vertical handover by finding fair and efficient
assignment schemes. On the one hand, mobiles gradually update the fraction of
data packets they send to each network based on the rewards they receive from
the stations. On the other hand, network stations send rewards to each mobile
that represent the impact each mobile has on the cell throughput. This reward
function is closely related to the concept of marginal cost in the pricing
literature. Both the station and the mobile algorithms are simple enough to be
implemented in current standard equipment. Based on tools from evolutionary
games, potential games and replicator dynamics, we analytically show the
convergence of the algorithm to solutions that are efficient and fair in terms
of throughput. Moreover, we show that after convergence, each user is connected
to a single network cell which avoids costly repeated vertical handovers.
Several simple heuristics based on this algorithm are proposed to achieve fast
convergence. Indeed, for implementation purposes, the number of iterations
should remain in the order of a few tens. We also compare, for different loads,
the quality of their solutions.


title: Bandlet Image Estimation with Model Selection

abstract:
  To estimate geometrically regular images in the white noise model and obtain
an adaptive near asymptotic minimaxity result, we consider a model selection
based bandlet estimator. This bandlet estimator combines the best basis
selection behaviour of the model selection and the approximation properties of
the bandlet dictionary. We derive its near asymptotic minimaxity for
geometrically regular images as an example of model selection with general
dictionary of orthogonal bases. This paper is thus also a self contained
tutorial on model selection with orthogonal bases dictionary.


title: On the geometry of biharmonic submanifolds in Sasakian space forms

abstract:
  We classify all proper-biharmonic Legendre curves in a Sasakian space form
and point out some of their geometric properties. Then we provide a method for
constructing anti-invariant proper-biharmonic submanifolds in Sasakian space
forms. Finally, using the Boothby-Wang fibration, we determine all
proper-biharmonic Hopf cylinders over homogeneous real hypersurfaces in complex
projective spaces.


title: Rotating light, OAM paradox and relativistic complex scalar field

abstract:
  Recent studies show that the angular momentum, both spin and orbital, of
rotating light beams possesses counter-intuitive characteristics. We present a
new approach to the question of orbital angular momentum of light based on the
complex massless scalar field representation of light. The covariant equation
for the scalar field is treated in rotating system using the general
relativistic framework. First we show the equivalence of the U(1) gauge current
for the scalar field with the Poynting vector continuity equation for paraxial
light, and then apply the formalism to the calculation of the orbital angular
momentum of rotating light beams. If the difference between the co-, contra-,
and physical quantities is properly accounted for there does not result any
paradox in the orbital angular momentum of rotating light. An artificial
analogue of the paradoxical situation could be constructed but it is wrong
within the present formalism. It is shown that the orbital angular momentum of
rotating beam comprising of modes with opposite azimuthal indices corresponds
to that of rigid rotation. A short review on the electromagnetism in
noninertial systems is presented to motivate a fully covariant Maxwell field
approach in rotating system to address the rotating light phenomenon.


title:
Gate fidelity of arbitrary single-qubit gates constrained by
  conservation laws

abstract:
  Recent investigations show that conservation laws limit the accuracy of gate
operations in quantum computing. The inevitable error under the angular
momentum conservation law has been evaluated so far for the CNOT, Hadamard, and
NOT gates for spin 1/2 qubits, while the SWAP gate has no constraint. Here, we
extend the above results to general single-qubit gates. We obtain an upper
bound of the gate fidelity of arbitrary single-qubit gates implemented under
arbitrary conservation laws, determined by the geometry of the conservation law
and the gate operation on the Bloch sphere as well as the size of the ancilla.


title: Photoionization of a strongly polarizable target

abstract:
  We demonstrate that the angular distribution of photoelectrons from a
strongly polarizable target exposed to a laser field can deviate noticeably
from the prediction of conventional theory. Even within the dipole-photon
approximation the profile of distribution is modified due to the action of the
field of alternating dipole moment induced at the residue by the laser field.
This effect, being quite sensitive to the dynamic polarizability of the residue
and to its geometry, depends also on the intensity and frequency of the laser
field. Numerical results, presented for sodium cluster anions, demonstrate that
dramatic changes to the profile occur for the photon energies in vicinities of
the plasmon resonances, where the effect is enhanced due to the increase in the
residue polarizability. Strong modifications of the characteristics of a
single-photon ionization process can be achieved by applying laser fields of
comparatively low intensities $I_0 \sim10^{10}-10^{11}$ W/cm$^2$.


title: The vector-valued non-homogeneous Tb theorem

abstract:
  The paper gives a Banach space -valued extension of the Tb theorem of
Nazarov, Treil and Volberg (2003) concerning the boundedness of singular
integral operators with respect to a measure, which only satisfies an upper
control on the size of balls. Under the same assumptions as in their result,
such operators are shown to be bounded on the Bochner spaces of functions with
values in a Banach space with the unconditionality property of martingale
differences (UMD). The new proof deals directly with all Lebesgue exponents p
in the range 1<p<infinity, and relies on delicate estimates for the
non-homogenous "Haar" functions, as well as McConnell's (1989) decoupling
inequality for tangent martingale differences.


title:
Time dependent simulation of the Driven Lid Cavity at High Reynolds
  Number

abstract:
  In this work, numerical solutions of the two dimensional time dependent
incompressible flow, in a driven cavity at high Reynolds number Re, are
presented. At high Re, there is a controversy. Some studies predicted that the
flow is steady, others found time dependent non-steady flow, either periodic or
aperiodic. In this study, the driven lid cavity is successfully solved using a
very fine grid mesh, for Re up to $30 000$. We discretize the Vorticity-Stream
formulation of the Navier-Stokes equation with the SSPRK(5,4) scheme in a
$1024\times1024$ grid. Using this very fine grid, the results obtained converge
to a stationary solution. Detailed results for Re between $5 000$ and $30 000$
are presented. The driven lid cavity problem is solved with a NVIDIA GPU using
the CUDA programming environment with double precision.


title:
A large sample of low surface brightness disk galaxies from the SDSS. I:
  The sample and the stellar populations

abstract:
  We present the properties of a large sample (12,282) of nearly face-on low
surface brightness (LSB) disk galaxies selected from the main galaxy sample of
SDSS-DR4. These properties include B-band central surface brightness mu_0(B),
scale lengths h, integrated magnitudes, colors, and distances D. This sample
has mu_0(B) values from 22 to 24.5 mag arcsec^{-2} with a median value of 22.42
mag arcsec^{-2}, and disk scale lengths ranging from 2 to 19 kpc. They are
quite bright with M_B taking values from -18 to -23 mag with a median value of
-20.08 mag. There exist clear correlations between logh and M_B, logh and logD,
logD and M_B. However, no obvious correlations are found between mu_0(B) and
logh, colors etc. The correlation between colors and logh is weak even though
it exists. Both the optical-optical and optical-NIR color-color diagrams
indicate that most of them have a mixture of young and old stellar populations.
They also satisfy color-magnitude relations, which indicate that brighter
galaxies tend generally to be redder. The comparison between the LSBGs and a
control sample of nearly face-on disk galaxies with higher surface brightness
(HSB) with mu_0(B) from 18.5 to 22 mag arcsec^{-2} show that, at a given
luminosity or distance, the observed LSB galaxies tend to have larger scale
lengths. These trends could be seen gradually by dividing both the LSBGs and
HSBGs into two sub-groups according to surface brightness. A volume-limited
sub-sample was extracted to check the incompleteness of surface brightness. The
only one of the property relations having an obvious change is the relation of
logh versus mu_0(B), which shows a correlation in this sub-sample.


title: On the relationship between BL Lacertae objects and radio galaxies

abstract:
  We present deep radio images at 1.4 GHz of a large and complete sample of BL
Lacertae objects (BL Lacs) selected from the Deep X-ray Radio Blazar Survey
(DXRBS). We have observed 24 northern sources with the Very Large Array (VLA)
in both its A and C configurations and 15 southern sources with the Australia
Telescope Compact Array (ATCA) in its largest configuration. We find that in
the DXRBS, as in the 1-Jy survey, which has a radio flux limit roughly ten
times higher than the DXRBS, a considerable number (about a third) of BL Lacs
can be identified with the relativistically beamed counterparts of
Fanaroff-Riley type II (FR II) radio galaxies. We attribute the existence of FR
II-BL Lacs, which is not accounted for by current unified schemes, to an
inconsistency in our classification scheme for radio-loud active galactic
nuclei (AGN). Taking the extended radio power as a suitable measure of
intrinsic jet power, we find similar average values for low- (LBL) and
high-energy peaked BL Lacs (HBL), contrary to the predictions of the blazar
sequence.


title: Magnification Bias Corrections to Galaxy-Lensing Cross-Correlations

abstract:
  Galaxy-galaxy or galaxy-quasar lensing can provide important information on
the mass distribution in the Universe. It consists of correlating the lensing
signal (either shear or magnification) of a background galaxy/quasar sample
with the number density of a foreground galaxy sample. However, the foreground
galaxy density is inevitably altered by the magnification bias due to the mass
between the foreground and the observer, leading to a correction to the
observed galaxy-lensing signal. The aim of this paper is to quantify this
correction. The single most important determining factor is the foreground
redshift z: the correction is small if the foreground galaxies are at low
redshifts but can become non-negligible for sufficiently high redshifts. For
instance, we find that for the multipole l=1000, the correction is above
1%*(5s-2)/b for z<0.37, and above 5%*(5s-2)/b for z<0.67, where s is the number
count slope of the foreground sample, and b its galaxy bias. These
considerations are particularly important for geometrical measures, such as the
Jain and Taylor ratio or its generalization by Zhang et al. Assuming
(5s-2)/b=1, we find that the foreground redshift should be limited to z<0.45 in
order to avoid biasing the inferred dark energy equation of state w by more
than 5%, and that even for a low foreground redshift (< 0.45), the background
samples must be well separated from the foreground to avoid incurring a bias of
similar magnitude. Lastly, we briefly comment on the possibility of obtaining
these geometrical measures without using galaxy shapes, using instead
magnification bias itself.


title: Degree-one maps, surgery and four-manifolds

abstract:
  We give a description of degree-one maps between closed, oriented 3-manifolds
in terms of surgery. Namely, we show that there is a degree-one map from a
closed, oriented 3-manifold $M$ to a closed, oriented 3-manifold $N$ if and
only if $M$ can be obtained from $N$ by surgery about a link in $N$ each of
whose components is an unknot.
  We use this to interpret the existence of degree-one maps between closed
3-manifolds in terms of smooth 4-manifolds. More precisely, we show that there
is a degree-one map from $M$ to $N$ if and only if there is a smooth embedding
of $M$ in $W=(N\times I)#_n \bar{\C P^2}#_m {\C P^2}$, for some $m\geq 0$,
$n\geq 0$ which separates the boundary components of $W$. This is motivated by
the relation to topological field theories, in particular the invariants of
Ozsvath and Szabo.


title:
Isospin phases of vertically coupled double quantum rings under the
  influence of perpendicular magnetic fields

abstract:
  Vertically coupled double quantum rings submitted to a perpendicular magnetic
field $B$ are addressed within the local spin-density functional theory. We
describe the structure of quantum ring molecules containing up to 40 electrons
considering different inter-ring distances and intensities of the applied
magnetic field. When the rings are quantum mechanically strongly coupled, only
bonding states are occupied and the addition spectrum of the artificial
molecules resembles that of a single quantum ring, with some small differences
appearing as an effect of the magnetic field. Despite the latter has the
tendency to flatten the spectra, in the strong coupling limit some clear peaks
are still found even when $B\neq 0$ that can be interpretated from the
single-particle energy levels analogously as at zero applied field, namely in
terms of closed-shell and Hund's-rule configurations. Increasing the inter-ring
distance, the occupation of the first antibonding orbitals washes out such
structures and the addition spectra become flatter and irregular. In the weak
coupling regime, numerous isospin oscillations are found as a function of $B$.


title: How to Construct a Dirac Operator in Infinite Dimensions

abstract:
  We define the notion of a co-Riemannian structure and show how it can be used
to define the Dirac operator on an appropriate infinite dimensional manifold.
In particular, this approach works for the smooth loop space of a so-called
string manifold.


title: A Proof On Arnold-Chekanov Conjecture

abstract:
  In this article, we give a proof on the Arnold-Chekanov Lagrangian
intersection conjecture on the cotangent bundles and its generalizations.


title:
T-entropy and Variational principle for the spectral radius of weighted
  shift operators

abstract:
  In this paper we introduce a new functional invariant of discrete time
dynamical systems -- the so-called t-entropy. The main result is that this
t-entropy is the Legendre dual functional to the logarithm of the spectral
radius of the weighted shift operator on $L^1(X,m)$ generated by the dynamical
system. This result is called the Variational principle and is similar to the
classical variational principle for the topological pressure.


title: Incompressibility and Least-Area surfaces

abstract:
  We show that if $F$ is a smooth, closed, orientable surface embedded in a
closed, orientable 3-manifold $M$ such that for each Riemannian metric $g$ on
$M$, $F$ is isotopic to a least-area surface $F(g)$, then $F$ is
incompressible.


title: The co-Riemannian Structure of Smooth Loop Spaces

abstract:
  We construct a natural co-Riemannian structure on the manifold of smooth
loops in a Riemannian manifold. We show that the smooth loop space of a string
manifold is a per-Hilbert-Schmidt locally equivalent co-spin manifold and thus
admits a Dirac operator.


title: Algebraic and Geometric intersection numbers for free groups

abstract:
  We show that the algebraic intersection number of Scott and Swarup for
splittings of free groups coincides with the geometric intersection number for
the sphere complex of the connected sum of copies of $S^2\times S^1$.


title: Watson-Crick pairing, the Heisenberg group and Milnor invariants

abstract:
  We study the secondary structure of RNA determined by Watson-Crick pairing
without pseudo-knots using Milnor invariants of links. We focus on the first
non-trivial invariant, which we call the Heisenberg invariant. The Heisenberg
invariant, which is an integer, can be interpreted in terms of the Heisenberg
group as well as in terms of lattice paths.
  We show that the Heisenberg invariant gives a lower bound on the number of
unpaired bases in an RNA secondary structure. We also show that the Heisenberg
invariant can predict \emph{allosteric structures} for RNA. Namely, if the
Heisenberg invariant is large, then there are widely separated local maxima
(i.e., allosteric structures) for the number of Watson-Crick pairs found.


title: Quantum manifolds with classical limit

abstract:
  We propose a mathematical model of quantum spacetime as an
infinite-dimensional manifold locally homeomorphic to an appropriate Schwartz
space. This extends and unifies both the standard function space construction
of quantum mechanics and the manifold structure of spacetime. In this picture
we demonstrate that classical spacetime emerges as a finite-dimensional
manifold through the topological identification of all quantum points with
identical position expectation value. We speculate on the possible relevance of
this geometry to quantum field theory and gravity.


title: The Physics Case for Axions, WIMPs, WISPs and Other Weird Stuff

abstract:
  We argue that there exists an excellent `physics case' motivating the search
for axions, WIMPs, WISPs and other phenomena testable at low energies. This
physics case arises from both experimental and observational evidence as well
as the desire to test theoretical model building.


title: Dynamics and constraints of the Unified Dark Matter flat cosmologies

abstract:
  We study the dynamics of the scalar field FLRW flat cosmological models
within the framework of the Unified Dark Matter (UDM) scenario. In this model
we find that the main cosmological functions such as the scale factor of the
Universe, the scalar field, the Hubble flow and the equation of state parameter
are defined in terms of hyperbolic functions. These analytical solutions can
accommodate an accelerated expansion, equivalent to either the dark energy or
the standard $\Lambda$ models. Performing a joint likelihood analysis of the
recent supernovae type Ia data and the Baryonic Acoustic Oscillations traced by
the SDSS galaxies, we place tight constraints on the main cosmological
parameters of the UDM cosmological scenario. Finally, we compare the UDM
scenario with various dark energy models namely $\Lambda$ cosmology, parametric
dark energy model and variable Chaplygin gas. We find that the UDM scalar field
model provides a large and small scale dynamics which are in fair agreement
with the predictions by the above dark energy models although there are some
differences especially at high redshifts.


title: Vortex Trapping in Hybrid Magnetometers

abstract:
  Hybrid magnetometers based on a normal conducting sensor and a
superconducting flux concentrator have been investigated. When this sensor is
operated in an unshielded environment flux vortices can be trapped in the
superconducting body when the sensor is cooled. Thermal hopping of the trapped
vortices gives rise to 1/f noise. The mechanism for vortex trapping has been
investigated. A new model for the critical field for vortex trapping and vortex
densities has been derived. Experimental verification on YBa2Cu3O7-delta (YBCO)
strips with a Scanning SQUID Microscope shows very good agreement between
measurements and the new theory. The results have been applied in a hybrid
magnetometer design based on a bismuth Hall sensor and an YBCO flux
concentrator. Measurements show a field gain up to G=7 with a large effective
range of 175uT.


title:
A new model for QPOs in accreting black holes: application to the
  microquasar GRS 1915+105

abstract:
  (abridged) In this paper we extend the idea suggested previously by Petri
(2005a,b) that the high frequency quasi-periodic oscillations observed in
low-mass X-ray binaries may be explained as a resonant oscillation of the
accretion disk with a rotating asymmetric background (gravitational or
magnetic) field imposed by the compact object. Here, we apply this general idea
to black hole binaries. It is assumed that a test particle experiences a
similar parametric resonance mechanism such as the one described in paper I and
II but now the resonance is induced by the interaction between a spiral density
wave in the accretion disk, excited close to the innermost stable circular
orbit, and vertical epicyclic oscillations. We use the Kerr spacetime geometry
to deduce the characteristic frequencies of this test particle. The response of
the test particle is maximal when the frequency ratio of the two strongest
resonances is equal to 3:2 as observed in black hole candidates. Finally,
applying our model to the microquasar GRS 1915+105, we reproduce the correct
value of several HF-QPOs. Indeed the presence of the 168/113/56/42/28 Hz
features in the power spectrum time analysis is predicted. Moreover, based only
on the two HF-QPO frequencies, our model is able to constrain the mass $M_{\rm
BH}$ and angular momentum $a_{\rm BH}$ of the accreting black hole.


title:
T-entropy and Variational Principle for the spectral radius of transfer
  and weighted shift operators

abstract:
  The paper deals with the variational principles for evaluation of the
spectral radii of transfer and weighted shift operators associated with a
dynamical system. These variational principles have been the matter of numerous
investigations and the principal results have been achieved in the situation
when the dynamical system is either reversible or it is a topological Markov
chain. As the main summands these principles contain the integrals over
invariant measures and the Kolmogorov--Sinai entropy. In the article we derive
the Variational Principle for an arbitrary dynamical system. It gives the
explicit description of the Legendre dual object to the spectral potential. It
is shown that in general this principle contains not the Kolmogorov--Sinai
entropy but a new invariant of entropy type -- the t-entropy.


title: Steiner t-designs for large t

abstract:
  One of the most central and long-standing open questions in combinatorial
design theory concerns the existence of Steiner t-designs for large values of
t. Although in his classical 1987 paper, L. Teirlinck has shown that
non-trivial t-designs exist for all values of t, no non-trivial Steiner
t-design with t > 5 has been constructed until now. Understandingly, the case t
= 6 has received considerable attention. There has been recent progress
concerning the existence of highly symmetric Steiner 6-designs: It is shown in
[M. Huber, J. Algebr. Comb. 26 (2007), pp. 453-476] that no non-trivial
flag-transitive Steiner 6-design can exist. In this paper, we announce that
essentially also no block-transitive Steiner 6-design can exist.


title: Dynamics and Synchrony from Oscillatory Data via Dimension Reduction

abstract:
  Complex, oscillatory data arises from a large variety of biological,
physical, and social systems. However, the inherent oscillation and ubiquitous
noise pose great challenges to current methodology such as linear and nonlinear
time series analysis. We exploit the state of the art technology in pattern
recognition and specifically, dimensionality reduction techniques, and propose
to rebuild the dynamics accurately on the cycle scale. This is achieved by
deriving a compact representation of the cycles through global optimization,
which effectively preserves the topology of the cycles that are embedded in a
high dimensional Euclidian space. Our approach demonstrates a clear success in
capturing the intrinsic dynamics and the subtle synchrony pattern from
uni/bivariate oscillatory data over traditional methods. Application to the
human locomotion data reveals important dynamical information which allows for
a clinically promising discrimination between healthy subjects and those with
neural pathology. Our results also provide fundamental implications for
understanding the neuromuscular control of human walking.


title:
Band Offsets at Semiconductor-Oxide Interfaces from Hybrid Density
  Functional Calculations

abstract:
  Band offsets at semiconductor-oxide interfaces are determined through a
scheme based on hybrid density functionals, which incorporate a fraction
$\alpha$ of Hartree-Fock exchange. For each bulk component, the fraction
$\alpha$ is tuned to reproduce the experimental band gap, and the conduction
and valence band edges are then located with respect to a reference level. The
lineup of the bulk reference levels is determined through an interface
calculation, and shown to be almost independent of the fraction $\alpha$.
Application of this scheme to the Si-SiO$_2$, SiC-SiO$_2$, and Si-HfO$_2$
interfaces yields excellent agreement with experiment.


title: Fingerprints of Random Flows?

abstract:
  We consider the patterns formed by small rod-like objects advected by a
random flow in two dimensions. An exact solution indicates that their direction
field is non-singular. However, we find from simulations that the direction
field of the rods does appear to exhibit singularities. First, ` scar lines'
emerge where the rods abruptly change direction by $\pi$. Later, these scar
lines become so narrow that they ` heal over' and disappear, but their ends
remain as point singularities, which are of the same type as those seen in
fingerprints. We give a theoretical explanation for these observations.


title:
Bifurcation Phenomena in Two-Dimensional Piecewise Smooth Discontinuous
  Maps

abstract:
  In recent years the theory of border collision bifurcations has been
developed for piecewise smooth maps that are continuous across the border, and
has been successfully applied to explain nonsmooth bifurcation phenomena in
physical systems. However, many switching dynamical systems have been found to
yield two-dimensional piecewise smooth maps that are discontinuous across the
border. The theory for understanding the bifurcation phenomena in such systems
is not available yet. In this paper we present the first approach to the
problem of analysing and classifying the bifurcation phenomena in
two-dimensional discontinuous maps, based on a piecewise linear approximation
in the neighborhood of the border. We explain the bifurcations occurring in the
static VAR compensator used in electrical power systems, using the theory
developed in this paper. This theory may be applied similarly to other systems
that yield two-dimensional discontinuous maps.


title: An orthogonality relation for multivariable Bessel polynomials

abstract:
  In a recent paper we introduced a multivariable generalisation of the Bessel
polynomials, depending on one extra parameter, and related to the so-called
hyperbolic Sutherland model with external Morse potential. In this paper we
obtain a corresponding multivariable generalisation of a well-known
orthogonality relation for the (one-variable) Bessel polynomials due to Krall
and Frink.


title:
Composite superstring model for hadrons and extended Virasoro
  superconformal symmetry with supercurrent constraints

abstract:
  Hadron dynamics is formulated in terms of interacting composite strings.
Consistent composite string model with extended Virasoro superconformal
symmetry is found. These composite strings carry flavour and chiral degrees of
freedom on edging two-dimensional surfaces. Necessary correct description of
string amplitudes without states of negative norms in the spectrum of physical
states is reached when special supercurrents conditions are fulfilled.


title: A minimal Little Higgs model

abstract:
  We discuss a Little Higgs scenario that introduces below the TeV scale just
the two minimal ingredients of these models, a vectorlike T quark and a singlet
component (implying anomalous couplings) in the Higgs field, together with a
pseudoscalar singlet \eta. In the model, which is a variation of Schmaltz's
simplest Little Higgs model, all the extra vector bosons are much heavier than
the T quark. In the Yukawa sector the global symmetry is approximate, implying
a single large coupling per flavour, whereas in the scalar sector it is only
broken at the loop level. We obtain the one-loop effective potential and show
that it provides acceptable masses for the Higgs h and for the singlet \eta
with no need for an extra \mu term. We find that m_\eta can be larger than
m_h/2, which would forbid the (otherwise dominant) decay mode h -> \eta\eta.


title:
Magnetohydrodynamic instability in differentially rotating compressible
  flow

abstract:
  Transport of angular momentum is one of the thrust areas of astrophysical
flows. Instabilities and hence the turbulence generated by it has been invoked
to understand its role in angular momentum transport in hydrodynamic and
magnetohydrodynamic regime. Investigation of an unexplored region described by
the parameter space $\Omega_e^2 < 0$, $\Omega_e$ being the epicyclic frequency,
resulted in a powerful magnetohydrodynamic instability. The growth rate of this
instability is rather large and is found to depend on the wavenumber.


title:
Spontaneous emission of atomic systems in the presence of incident
  fields

abstract:
  We characterise the spontaneous emission time and direction from small
numbers of dipole-coupled two-level atoms (2LAs) in the presence of incident
fields. We show how to use adiabatic passage to admit population transfer
between states in the one-quantum subspace for two and three 2LAs. Our method
is a multi-atom generalisation of stimulated-Raman-adiabatic-passage (STIRAP)
for a single multi-level atom. We use numerical results to justify an ansatz
that enables us to give analytical expressions for the directional emission
which depends on the incident fields. Our results admit a characterisation of
the efficacy of population transfer in small numbers of dipole-coupled 2LAs,
and are applicable to proof-of-principle experiments involving dipole-coupled
2LAs.


title: On the norm of the Beurling-Ahlfors operator in several dimensions

abstract:
  The Lp operator norm of the generalized Beurling-Ahlfors transformation in n
variables is at most (n/2+1)(p-1) for p>2. This improves on earlier results in
all dimensions n>2. The proof is based on the heat extension and relies at the
bottom on Burkholder's sharp inequality for martingale transforms.


title: The geometry of Schr\"odinger symmetry in non-relativistic CFT

abstract:
  The non-relativistic conformal "Schroedinger" symmetry of some gravity
backgrounds proposed recently in the AdS/CFT context, is explained in the
"Bargmann framework". The formalism incorporates the Equivalence Principle.
Newton-Hooke conformal symmetries, which are analogs of those of Schroedinger
in the presence of a negative cosmological constant, are discussed in a similar
way. Further examples include topologically massive gravity with negative
cosmological constant and the Madelung hydrodynamical description.


title: Kurtosis and compressibility near the chiral phase transition

abstract:
  The properties of net quark number fluctuations in the vicinity of the QCD
chiral phase transition are discussed in terms of an effective chiral model in
the mean-field approximation. We focus on the ratio of the fourth- to second-
order cumulants (kurtosis) and the compressibility of the system and discuss
their dependence on the pion mass. It is shown that near the chiral phase
transition, both observables are sensitive to the value of $m_\pi$. For
physical $m_\pi$, the kurtosis exhibits a peak whereas the inverse
compressibility shows a dip at the pseudocritical temperature. These structures
disappear for large $m_\pi$. Our results, obtained in an effective model with
two flavors, are qualitatively consistent with recent results of 2+1 flavor
lattice gauge theory. We also discuss the high- and low-temperature properties
of these observables and the role of the coupling of the quark degrees of
freedom to the Polyakov loop.


title: Azimuthal anisotropy and fundamental symmetries in QCD matter at RHIC

abstract:
  A study of collective behavior in heavy ion collisions provides one of the
most sensitive and promising probes for investigation of possible formation of
new extreme state of strong interacting matter and elucidating its properties.
Systematic of experimental results for final state azimuthal anisotropy is
presented for heavy ion interactions at RHIC. Experimental data for azimuthal
anisotropy indicate that the final state strongly interacting matter under
extreme conditions behaves as near-ideal liquid rather, than ideal gas of
quarks and gluons. The strong quenching of jets and the dramatic modification
of jet-like azimuthal correlations, observed in ${Au+Au}$ collisions, are
evidences of the extreme energy loss of partons traversing matter which
contains a large density of color charges. For the first time, dependence of
the jet suppression on orientation of a jet with respect to the reaction plane
is found at RHIC experimentally. The model of compound collective flow and
corresponding analytic approach are discussed. The possible violations of
$\cal{P}$ and $\cal{CP}$ symmetries of strong interactions in heavy ion
collisions at different initial energies are considered. Thus, now the fact is
established firmly, that extremely hot and dense matter created in relativistic
heavy ion collisions at RHIC differs dramatically from everything that was
observed and investigated before.


title: Anosov Automorphisms of Nilpotent Lie Algebras

abstract:
  Each matrix A in GL_n(Z) naturally defines an automorphism f of the free
r-step nilpotent Lie algebra on n generators. We study the relationship between
the matrix A and the eigenvalues and rational invariant subspaces for f. We
give applications to the study of Anosov automorphisms.


title: On Quasitoric Orbifolds

abstract:
  Quasitoric spaces were introduced by Davis and Januskiewicz in their 1991
Duke paper. There they extensively studied topological invariants of quasitoric
manifolds.
  These manifolds are generalizations or topological counterparts of
nonsingular projective toric varieties. In this article we study structures and
invariants of quasitoric orbifolds. In particular, we discuss equivalent
definitions and determine the orbifold fundamental group, rational homology
groups and cohomology ring of a quasitoric orbifold. We determine whether any
quasitoric orbifold can be the quotient of a smooth manifold by a finite group
action or not. We prove existence of stable almost complex structure and
describe the Chen-Ruan cohomology groups of an almost complex quasitoric
orbifold.