title: Fractal scale-free networks resistant to disease spread

abstract:
  In contrast to the conventional wisdom that scale-free networks are prone to
epidemic propagation, in the paper we present that disease spreading is
inhibited in fractal scale-free networks. We first propose a novel network
model and show that it simultaneously has the following rich topological
properties: scale-free degree distribution, tunable clustering coefficient,
"large-world" behavior, and fractal scaling. Existing network models do not
display these characteristics. Then, we investigate the
susceptible-infected-removed (SIR) model of the propagation of diseases in our
fractal scale-free networks by mapping it to bond percolation process. We find
an existence of nonzero tunable epidemic thresholds by making use of the
renormalization group technique, which implies that power-law degree
distribution does not suffice to characterize the epidemic dynamics on top of
scale-free networks. We argue that the epidemic dynamics are determined by the
topological properties, especially the fractality and its accompanying
"large-world" behavior.


title:
Generation of quantum-dot cluster states with superconducting
  transmission line resonator

abstract:
  We propose an efficient method to generate cluster states in spatially
separated double quantum dots with a superconducting transmission line
resonator (TLR). When the detuning between the double-dot qubits transition
frequency and the frequency of the full wave mode in the TLR satisfies some
conditions, an Ising-like operator between arbitrary two separated qubits can
be achieved. Even including the main noise sources, it's shown that the high
fidelity cluster states could be generated in this solid system in just one
step.


title: Nonlinear magnetic response in ruthenocuprates

abstract:
  We have performed an investigation of the nonlinear magnetic response in
ruthenocuprates. A negative, diverging-like peak at the main magnetic
transition T_N in RuSr2RECu2O8 (RE = Gd, Y) indicates a possible canted
antiferromagnetic order. Another well defined feature above T_N points to a
blocking of superparamagnetic particles through the T^(-3) dependence of the
third harmonic at higher temperatures. Below T_N a nondiverging peak appears,
which is strongly affected by the addition of 10% of Cu ions in the RuO2
planes. In RuSr2RE(2-x)Ce(x)Cu2O10 the main magnetic transition T_M is
accompanied by two characteristic temperatures in the third harmonic of the ac
susceptibility, in agreement with recent studies from uSR and Mossbauer
spectroscopy. We find that the spin-spin correlation temperature is the same in
both families of ruthenocuprates.


title: A summation by Gencev

abstract:
  Gencev has recently reported a closed form summation for an infinite series
involving the harmonic numbers and the central binomial numbers. This note
indicates a possible approach to the proof involving the dilogarithm function.


title:
Nonlinear Photoluminescence Excitation Spectroscopy of Carbon Nanotubes:
  Exploring the Upper Density Limit of One-Dimensional Excitons

abstract:
  We have studied emission properties of high-density excitons in single-walled
carbon nanotubes through nonlinear photoluminescence excitation spectroscopy.
As the excitation intensity was increased, all emission peaks arising from
different chiralities showed clear saturation in intensity. Each peak exhibited
a saturation value that was independent of the excitation wavelength,
indicating that there is an upper limit on the exciton density for each
nanotube species. We developed a theoretical model based on exciton diffusion
and exciton-exciton annihilation that successfully reproduced the saturation
behavior, allowing us to estimate exciton densities. These estimated densities
were found to be still substantially smaller than the expected Mott density
even in the saturation regime, in contrast to conventional semiconductor
quantum wires.


title: Accurate Model of a Vertical Pillar Quantum Dot

abstract:
  An accurate model of a vertical pillar quantum dot is described. The full
three dimensional structure of the device containing the dot is taken into
account and this leads to an effective two dimensional model in which electrons
move in the two lateral dimensions, the confinement is parabolic and the
interaction potential is very different from the bare Coulomb potential. The
potentials are found from the device structure and a few adjustable parameters.
Numerically stable calculation procedures for the interaction potential are
detailed and procedures for deriving parameter values from experimental
addition energy and chemical potential data are described. The model is able to
explain magnetic field dependent addition energy and chemical potential data
for an individual dot to an accuracy of about 5%, the accuracy level needed to
determine ground state quantum numbers from experimental transport data.
Applications to excited state transport data are also described.


title: Hyperbolic Dynamical Systems

abstract:
  The theory of uniformly hyperbolic dynamical systems was initiated in the
1960's (though its roots stretch far back into the 19th century) by S. Smale,
his students and collaborators, in the west, and D. Anosov, Ya. Sinai, V.
Arnold, in the former Soviet Union. It came to encompass a detailed description
of a large class of systems, often with very complex evolution. Moreover, it
provided a very precise characterization of structurally stable dynamics, which
was one of its original main goals. The early developments were motivated by
the problem of characterizing structural stability of dynamical systems, a
notion that had been introduced in the 1930's by A. Andronov and L. Pontryagin.
Inspired by the pioneering work of M. Peixoto on circle maps and surface flows,
Smale introduced a class of gradient-like systems, having a finite number of
periodic orbits, which should be structurally stable and, moreover, should
constitute the majority (an open and dense subset) of all dynamical systems.
Stability and openness were eventually established, in the thesis of J. Palis.
However, contemporary results of M. Levinson, based on previous work by M.
Cartwright and J. Littlewood, provided examples of open subsets of dynamical
systems all of which have an infinite number of periodic orbits.


title: Symbolic computations in differential geometry

abstract:
  We introduce the C++ library Wedge, based on GiNaC, for symbolic computations
in differential geometry. We show how Wedge makes it possible to use the
language C++ to perform such computations, and illustrate some advantages of
this approach with explicit examples. In particular, we describe a short
program to determine whether a given linear exterior differential system is
involutive.


title:
Representations of unramified U(2,2) over a p-adic field I:
  representations of non-integral level

abstract:
  Let F_0 be a non-archimedean local field of odd residual characteristic and
let G be the unramified unitary group U(2,2) defined over F_0. In this paper,
we give a classification of the irreducible smooth representations of G of
non-integral level using the Hecke algebraic method developed by Allen Moy for
GSp(4).


title:
Z', Z_KK, Z* and all that: current bounds and theoretical prejudices on
  heavy neutral vector bosons

abstract:
  I review the current experimental bounds and theoretical predictions for
different kinds of heavy neutral vector bosons.


title:
A Hidden Local Field Theory Description of Dileptons in Relativistic
  Heavy Ion Collisions

abstract:
  This paper has been withdrawn by the authors. Some of the arguments developed
in the paper are erroneous. They will be rectified in a later publication.


title: Neutral nuclear core vs super charged one

abstract:
  Based on the Thomas-Fermi approach, we describe and distinguish the electron
distributions around extended nuclear cores: (i) in the case that cores are
neutral for electrons bound by protons inside cores and proton and electron
numbers are the same; (ii) in the case that super charged cores are bare,
electrons (positrons) produced by vacuum polarization are bound by (fly into)
cores (infinity).


title: $B \to K_1 \gamma$ Decays in the Light-Cone QCD Sum Rules

abstract:
  We present a detailed study of $B\to K_1(1270) \gamma$ and $B\to K_1(1400)
\gamma$ decays. Using the light-cone sum rule technique, we calculate the $B\to
K_{1A} (1^3P_1)$ and $B\to K_{1B} (1^1P_1)$ tensor form factors,
$T_1^{K_{1A}}(0)$ and $T_1^{K_{1B}}(0)$, where the contributions are included
up to the first order in $m_{K_1}/m_b$. We resolve the sign ambiguity of the
$K_1(1270)$--$K_1(1400)$ mixing angle $\theta_{K_1}$ by defining the signs of
decay constants, $f_{K_{1A}}$ and $f_{K_{1B}}^\perp$. From the comparison of
the theoretical calculation and the data for decays $B\to K_1 \gamma$ and
$\tau^-\to K_1^-(1270)\nu_\tau$, we find that $\theta_{K_1}=-(34\pm 13)^\circ$
is favored. In contrast to $B\to K^* \gamma$, the hard-spectator contribution
suppresses the $B\to K_1(1270) \gamma$ and $B\to K_1(1400) \gamma$ branching
ratios slightly. The predicted branching ratios are in agreement with the Belle
measurement within the errors. We point out that a more precise measurement for
the ratio $R_{K_1}={\cal B}(B\to K_1(1400)\gamma)/{\cal B}(B\to
K_1(1270)\gamma)$ can offer a better determination for the $\theta_{K_1}$ and
consequently the theoretical uncertainties can be reduced.


title: Computable counter-examples to the Brouwer fixed-point theorem

abstract:
  This paper is an overview of results that show the Brouwer fixed-point
theorem (BFPT) to be essentially non-constructive and non-computable. The main
results, the counter-examples of Orevkov and Baigger, imply that there is no
procedure for finding the fixed point in general by giving an example of a
computable function which does not fix any computable point. Research in
reverse mathematics has shown the BFPT to be equivalent to the weak K\"onig
lemma in RCA$_0$ (the system of recursive comprehension) and this result is
illustrated by relating the weak K\"onig lemma directly to the Baigger example.


title:
Statistical analysis of the transmission based on the DMPK equation: An
  application to Pb nano-contacts

abstract:
  The density of the transmission eigenvalues of Pb nano-contacts has been
estimated recently in mechanically controllable break-junction experiments.
Motivated by these experimental analyses, here we study the evolution of the
density of the transmission eigenvalues with the disorder strength and the
number of channels supported by the ballistic constriction of a quantum point
contact in the framework of the Dorokhov-Mello-Pereyra-Kumar equation. We find
that the transmission density evolves rapidly into the density in the diffusive
metallic regime as the number of channels $N_c$ of the constriction increase.
Therefore, the transmission density distribution for a few $N_c$ channels comes
close to the known bimodal density distribution in the metallic limit. This is
in agreement with the experimental statistical-studies in Pb nano-contacts. For
the two analyzed cases, we show that the experimental densities are seen to be
well described by the corresponding theoretical results.


title:
Overcharging, charge inversion and reentrant condensation: Using
  highly-charged polyelectrolytes in tetravalent salt solutions as an example
  of study

abstract:
  We study salt-induced charge overcompensation and charge inversion of
flexible polyelectrolytes via computer simulations and demonstrate the
importance of ion excluded volume. Reentrant condensation takes place when the
ion size is comparable to monomer size, and happens in a middle region of salt
concentration. In a high-salt region, ions can overcharge a chain near its
surface and charge distribution around a chain displays an oscillatory
behavior. Unambiguous evidence obtained by electrophoresis shows that charge
inversion does not necessarily appear with overcharging and occurs when the ion
size is not big. These findings suggest a disconnection of resolubilization of
polyelectrolyte condensates at high salt concentration with charge inversion.


title: Generalized eigenvalue-counting estimates for the Anderson model

abstract:
  We generalize Minami's estimate for the Anderson model and its extensions to
$n$ eigenvalues, allowing for $n$ arbitrary intervals and arbitrary single-site
probability measures with no atoms. As an application, we derive new results
about the multiplicity of eigenvalues and Mott's formula for the
ac-conductivity when the single site probability distribution is H\"older
continuous.


title: Galactic Rotation Described with Bulge+Disk Gravitational Models

abstract:
  Observations reveal that mature spiral galaxies consist of stars, gases and
plasma approximately distributed in a thin disk of circular shape, usually with
a central bulge. The rotation velocities quickly increase from the galactic
center and then achieve a constant velocity from the core to the periphery. The
basic dynamic behavior of a mature spiral galaxy, such as the Milky Way, is
well described by simple models balancing Newtonian gravitational forces
against the centrifugal forces associated with a rotating thin axisymmetric
disk. In this research, we investigate the effects of adding central bulges to
thin disk gravitational models. Even with the addition of substantial central
bulges, all the critical essential features of our thin disk gravitational
models are preserved. (1) Balancing Newtonian gravitational and centrifugal
forces at every point within the disk yields computed radial mass distributions
that describe the measured rotation velocity profiles of mature spiral galaxies
successfully. (2) There is no need for gravity deviations or ``massive
peripheral spherical halos of mysterious Dark Matter''. (3) The calculated
total galactic masses are in good agreement with star count data. (4) The
addition of central bulges increases the calculated total galactic masses,
possibly more consistent with the presence of galactic gases, dust, grains,
lumps, planets and plasma in addition to stars. (5) Compared with the light
distribution, our mass distributions within the disk are larger out toward the
galactic periphery which is cooler with lower opactiy/emissivity (and thus
darker). This is apparent from edge-on views of galaxies which display a dark
disk-line against a much brighter galactic halo.


title:
Conserving approximations in direct perturbation theory: new
  semianalytical impurity solvers and their application to general lattice
  problems

abstract:
  For the treatment of interacting electrons in crystal lattices approximations
based on the picture of effective sites, coupled in a self-consistent fashion,
have proven very useful. Particularly in the presence of strong local
correlations, a local approach to the problem, combining a powerful method for
the short ranged interactions with the lattice propagation part of the
dynamics, determines the quality of results to a large extent. For a
considerable time the non crossing approximation (NCA) in direct perturbation
theory, an approach originally developed by Keiter for the Anderson impurity
model, built a standard for the description of the local dynamics of
interacting electrons. In the last couple of years exact methods like the
numerical renormalization group (NRG) as pioneered by Wilson, have surpassed
this approximation as regarding the description of the low energy regime. We
present an improved approximation level of direct perturbation theory for
finite Coulomb repulsion U, the crossing approximation one (CA1) and discuss
its connections with other generalizations of NCA. CA1 incorporates all
processes up to fourth order in the hybridization strength V in a
self-consistent skeleton expansion, retaining the full energy dependence of the
vertex functions. We reconstruct the local approach to the lattice problem from
the point of view of cumulant perturbation theory in a very general way and
discuss the proper use of impurity solvers for this purpose. Their reliability
can be tested in applications to e.g. the Hubbard model and the
Anderson-lattice model. We point out shortcomings of existing impurity solvers
and improvements gained with CA1 in this context.
  This paper is dedicated to the memory of Hellmut Keiter.


title: Stability of Universal Equivalence of Groups under Free Constructions

abstract:
  In 1971 J. Stallings introduced a generalisation of amalgamated products of
groups -- called a pregroup, which is a particular kind of a partial group. He
defined the universal group U(P) of a pregroup P to be a universal object (in
the sense of category theory) extending the partial operations on P to group
operations on U(P). This turns out to be a versatile and convenient
generalisation of classical group constructions: HNN-extensions and amalgamated
products. In this respect the following general question arises. Which
properties of pregroups, or relations between pregroups, carry over to the
respective universal groups? In this paper it is proved that universal
equivalence of pregroups extends to universal equivalence of universal groups.
Applications to free products with amalgamation and HNN-extensions are then
described.


title: Spacetime path formalism for massive particles of any spin

abstract:
  Earlier work presented a spacetime path formalism for relativistic quantum
mechanics arising naturally from the fundamental principles of the Born
probability rule, superposition, and spacetime translation invariance. The
resulting formalism can be seen as a foundation for a number of previous
parameterized approaches to relativistic quantum mechanics in the literature.
Because time is treated similarly to the three space coordinates, rather than
as an evolution parameter, such approaches have proved particularly useful in
the study of quantum gravity and cosmology. The present paper extends the
foundational spacetime path formalism to include massive, nonscalar particles
of any (integer or half-integer) spin. This is done by generalizing the
principle of translational invariance used in the scalar case to the principle
of full Poincare invariance, leading to a formulation for the nonscalar
propagator in terms of a path integral over the Poincare group. Once the
difficulty of the non-compactness of the component Lorentz group is dealt with,
the subsequent development is remarkably parallel to the scalar case. This
allows the formalism to retain a clear probabilistic interpretation throughout,
with a natural reduction to non-relativistic quantum mechanics closely related
to the well known generalized Foldy-Wouthuysen transformation.


title:
Lookup tables to compute high energy cosmic ray induced atmospheric
  ionization and changes in atmospheric chemistry

abstract:
  A variety of events such as gamma-ray bursts and supernovae may expose the
Earth to an increased flux of high-energy cosmic rays, with potentially
important effects on the biosphere. Existing atmospheric chemistry software
does not have the capability of incorporating the effects of substantial cosmic
ray flux above 10 GeV . An atmospheric code, the NASA-Goddard Space Flight
Center two-dimensional (latitude, altitude) time-dependent atmospheric model
(NGSFC), is used to study atmospheric chemistry changes. Using CORSIKA, we have
created tables that can be used to compute high energy cosmic ray (10 GeV - 1
PeV) induced atmospheric ionization and also, with the use of the NGSFC code,
can be used to simulate the resulting atmospheric chemistry changes. We discuss
the tables, their uses, weaknesses, and strengths.

categories: astro-ph astro-ph.HE hep-ex hep-ph hep-th physics.ao-ph


title:
A Blaschke-type condition for analytic and subharmonic functions and
  application to contraction operators

abstract:
  Let $E$ be a closed set on the unit circle. We find a Blaschke-type
condition, optimal in a sense of the order, on the Riesz measure of a
subharmonic function $v$ in the unit disk with a certain growth at the
direction of $E$. In particular case when $E$ is a finite set, and $v=\log|f|$
with an analytic function $f$, our result agrees with the recent one by A.
Borichev, L. Golinskii and S. Kupin. An application to contractions close to
unitary operators in the Hilbert space is given.


title:
Convex Risk Measures: Lebesgue Property on one Period and Multi Period
  Risk Measures and Application in Capital Allocation Problem

abstract:
  In this work we study the Lebesgue property for convex risk measures on the
space of bounded c\`adl\`ag random processes ($\mathcal{R}^\infty$). Lebesgue
property has been defined for one period convex risk measures in \cite{Jo} and
earlier had been studied in \cite{De} for coherent risk measures. We introduce
and study the Lebesgue property for convex risk measures in the multi period
framework. We give presentation of all convex risk measures with Lebesgue
property on bounded c\`adl\`ag processes. To do that we need to have a complete
description of compact sets of $\mathcal{A}^1$. The main mathematical
contribution of this paper is the characterization of the compact sets of
$\mathcal{A}^p$ (including $\mathcal{A}^1$). At the final part of this paper,
we will solve the Capital Allocation Problem when we work with coherent risk
measures.


title:
Introduction to String Theory and Gauge/Gravity duality for students in
  QCD and QGP phenomenology

abstract:
  String theory has been initially derived from motivations coming from strong
interaction phenomenology,but its application faced deep conceptual and
practical difficulties. The strong interactions found their theoretical
foundation elsewhere, namely on QCD, the quantum gauge field theory of quarks
and gluons. Recently, the Gauge/Gravity correspondence allowed to initiate a
reformulation of the connection between strings and gauge field theories,
avoiding some of the initial drawbacks and opening the way to new insights on
the gauge theory at strong coupling and eventually QCD. Among others, the
recent applications of the Gauge/Gravity correspondence to the formation of the
QGP, the quark-gluon plasma, in heavy-ion reactions seem to provide a
physically interesting insight on phenomenological features of the reactions.
In these lectures we will give a simplified introduction to those aspects of
string theory which, at the origin and in the recent developments, are
connected to strong interactions, for those students which are starting to
learn QCD and QGP physics from an experimental or phenomenological point of
view.


title: A structural approach to subset-sum problems

abstract:
  We discuss a structural approach to subset-sum problems in additive
combinatorics. The core of this approach are Freiman-type structural theorems,
many of which will be presented through the paper. These results have
applications in various areas, such as number theory, combinatorics and
mathematical physics.


title:
Relation between phase and dwell times for quantum tunneling of a
  relativistically propagating particle

abstract:
  The general and explicit relation between the phase time and the dwell time
for quantum tunneling of a relativistically propagating particle is
investigated and quantified. In analogy with previously obtained
non-relativistic results, it is shown that the group delay can be described in
terms of the dwell time and a self-interference delay. Lessons concerning the
phenomenology of the relativistic tunneling are drawn.


title: Neutrino orbital angular momentum in a plasma vortex

abstract:
  It is shown that an electron-neutrino beam, propagating in a background
plasma, can be decomposed into orbital momentum (OAM) states, similar to the
OAM photon states. Coupling between different OAM neutrino states, in the
presence of a plasma vortex, is considered. We show that plasma vorticity can
be transfered to the neutrino beam, which is relevant to the understanding of
the neutrino sources in astrophysics. Observation of neutrino OAM states could
eventually become possible.


title: Poisson automorphisms and quiver moduli

abstract:
  A factorization formula for certain automorphisms of a Poisson algebra
associated to a quiver is proved, which involves framed versions of moduli
spaces of quiver representations. This factorization formula is related to
wall-crossing formulas for Donaldson-Thomas type invariants of M. Kontsevich
and Y. Soibelman.


title: Multicast Capacity of Optical WDM Packet Ring for Hotspot Traffic

abstract:
  Packet-switching WDM ring networks with a hotspot transporting unicast,
multicast, and broadcast traffic are important components of high-speed
metropolitan area networks. For an arbitrary multicast fanout traffic model
with uniform, hotspot destination, and hotspot source packet traffic, we
analyze the maximum achievable long-run average packet throughput, which we
refer to as \textit{multicast capacity}, of bi-directional shortest-path routed
WDM rings. We identify three segments that can experience the maximum
utilization, and thus, limit the multicast capacity. We characterize the
segment utilization probabilities through bounds and approximations, which we
verify through simulations. We discover that shortest-path routing can lead to
utilization probabilities above one half for moderate to large portions of
hotspot source multi- and broadcast traffic, and consequently multicast
capacities of less than two simultaneous packet transmissions. We outline a
one-copy routing strategy that guarantees a multicast capacity of at least two
simultaneous packet transmissions for arbitrary hotspot source traffic.


title: Two-photon decay of a light scalar quark-antiquark state

abstract:
  The two-photon decay of a light scalar quarkonium is evaluated in a local and
a nonlocal approaches. It is shown that the two-photon decay, driven by a
triangle quark-loop diagram, is smaller than 1 keV for a mass below 0.7 GeV.


title: Epidermal corneocytes: dead guards of the hidden treasure

abstract:
  Gradual transformation of the epidermal stem cells to corneocytes involves a
chain of chronologically well-arranged events that mostly stimulated locally by
their neighbors. Cell diversity that observed during the differentiation
through the different epidermal cell layers included the consisted changes of
cell shape, intercellular contacts and proliferation. However, the most
dramatically these changes appeared at the molecular level through gene
expression, catalysis and intraprotein interactions. The proposed review
explains these changes by switching systemic transcription factors that unlike
their counterparts those role is limited to a contribution to gene expression
also prepare cells to the next step of differentiation via modification of the
chromatin pattern . Since primary epidermal keratinocytes are one of the most
easy available type of the stem cells, a better understanding of the epidermal
differentiation will benefit the research in the other areas by a discovery of
basic coordinating mechanisms that stand behind such distinct molecular events
as cell signaling and gene expression, and formulate basic principles for a
smart therapeutic correction of the metabolism.


title: A tessellation for algebraic surfaces in CP3

abstract:
  We present an explicit algorithm for tessellating the algebraic surfaces
(real 4-manifolds) F(n) embedded in CP3 defined by the equation z0^n + z1^n +
z2^n + z3^n = 0 in the standard homogeneous coordinates [z0, z1, z2, z3], where
n is any positive integer. Note that F(4) in particular is a K3 surface. Our
tessellation contains a minimal number of vertices, namely the n-th roots of
unity in the six standard projective lines CP1 in CP3, which form an obvious
framework for constructing a natural tessellation of F(n). Our tessellation is
invariant under the action of the obvious isomorphism group of F(n) induced by
permutations and phase multiplications of the coordinates, and the action is
transitive on the set of 4-cells. The tessellation is built upon a similar
triangulation for the corresponding algebraic curves in CP2.


title: Charge pumping in carbon nanotube quantum dots

abstract:
  We investigate charge pumping in carbon nanotube quantum dots driven by the
electric field of a surface acoustic wave. We find that at small driving
amplitudes, the pumped current reverses polarity as the conductance is tuned
through a Coulomb blockade peak using a gate electrode. We study the behavior
as a function of wave amplitude, frequency and direction and develop a model in
which our results can be understood as resulting from adiabatic charge
redistribution between the leads and quantum dots on the nanotube.


title:
Measurement of the forward-backward charge asymmetry and extraction of
  sin^2Theta^{eff}_W in ppbar -> Z/\gamma^{*}+X -> e+e+X events produced at
  \sqrt{s}=1.96 TeV

abstract:
  We present a measurement of the forward-backward charge asymmetry ($A_{FB}$)
in $p\bar{p} \to Z/\gamma^{*}+X \to e^+e^-+X$ events at a center-of-mass energy
of 1.96 TeV using 1.1 fb$^{-1}$ of data collected with the D0 detector at the
Fermilab Tevatron collider. $A_{FB}$ is measured as a function of the invariant
mass of the electron-positron pair, and found to be consistent with the
standard model prediction. We use the $A_{FB}$ measurement to extract the
effective weak mixing angle $sin^2Theta^{eff}_W = 0.2327 \pm 0.0018 (stat.) \pm
0.0006 (syst.)$.


title: Photon orbital angular momentum in a plasma vortex

abstract:
  We study theoretically the exchange of angular momentum between a photon beam
and a plasma vortex, and demonstrate the possible excitation of photon angular
momentum states in a plasma. This can be relevant to laboratory and space
plasma diagnostics; radio astronomy self-calibration; and generating photon
angular momentum beams. A static plasma perturbation with helical structure,
and a rotating plasma vortex are studied in detail and a comparison between
these two cases, and their relevance to the physical nature of photon OAM, is
established.


title: Algebraically general, gravito-electric rotating dust

abstract:
  The class of gravito-electric, algebraically general, rotating `silent' dust
space-times is studied. The main invariant properties are deduced. The number
$t_0$ of functionally independent zero-order Riemann invariants satisfies
$1\leq t_0\leq 2$ and special attention is given to the subclass $t_0=1$.
Whereas there are no $\Lambda$-term limits comprised in the class, the limit
for vanishing vorticity leads to two previously derived irrotational dust
families with $\Lambda>0$, and the shear-free limit is the G\"{o}del universe.


title:
The Behavior of the Aromatic Features in M101 HII Regions: Evidence for
  Dust Processing

abstract:
  The aromatic features in M101 were studied spectroscopically and
photometrically using observations from all three instruments on the Spitzer
Space Telescope. The global SED of M101 shows strong aromatic feature (commonly
called PAH feature) emission. The spatially resolved spectral and photometric
measurements of the aromatic feature emission show strong variations with
significantly weaker emission at larger radii. We compare these variations with
changes in the ionization index (as measured by [NeIII]/[NeII] and [SIV/SIII],
which we probe over the ranges 0.03-20 and 0.044-15 respectively) and
metallicity (expressed as log(O/H)+12, which ranges from 8.1 to 8.8). Over
these ranges, the spectroscopic equivalent widths of the aromatic features from
7 HII regions and the nucleus were found to correlate better with ionization
index than with metallicity. This implies that the weakening of the aromatic
emission in massive star forming regions is due primarily to processing of the
dust grains in these environments, not to differences in how they form
(although formation could still be important on a secondary basis). The
behavior of the correlation between the aromatic feature equivalent widths and
ionization index can be described as a constant equivalent width until a
threshold in ionization index is reached ([NeIII]/[NeII] ~ 1), above which the
equivalent widths decrease with a power law dependence. This behavior for M101
HII regions is also seen for the sample of starburst galaxies presented in the
companion study of Engelbracht et al. (2008) which expands the range of
[NeIII]/[NeII] ratios to 0.03-25 and log(O/H)+12 values to 7.1-8.8. The form of
the correlation explains seemingly contradictory results present in the
literature. [abridged]


title: DNA cages with icosahedral symmetry in bionanotechnology

abstract:
  Blueprints of polyhedral cages with icosahedral symmetry made of circular DNA
molecules are provided. The basic rule is that every edge of the cage is met
twice in opposite directions by the DNA strand, and vertex junctions are
realised by a set of admissible junction types. As nanocontainers for cargo
storage and delivery, the icosidodecahedral cages are of special interest as
they have the largest volume per surface ratio of all cages discussed here.


title: Stability Functions

abstract:
  In this article we discuss the role of stability functions in geometric
invariant theory and apply stability function techniques to problems in toric
geometry. In particular we show how one can use these techniques to recover
results of Burns-Guillemin-Uribe and Shiffman-Tate-Zelditch on asymptotic
properties of sections of holomorphic line bundles over toric varieties.


title: On generators of bounded ratios of minors for totally positive matrices

abstract:
  We provide a method for factoring all bounded ratios of the form $$\det
A(I_1|I_1')\det A(I_2|I_2')/\det A(J_1|J_1')\det A(J_2|J_2')$$ where $A$ is a
totally positive matrix, into a product of more elementary ratios each of which
is bounded by 1, thus giving a new proof of Skandera's result. The approach we
use generalizes the one employed by Fallat et al. in their work on principal
minors. We also obtain a new necessary condition for a ratio to be bounded for
the case of non-principal minors.


title:
Canonical partition function and finite density phase transition in
  lattice QCD

abstract:
  We discuss the nature of the phase transition for lattice QCD at finite
temperature and density. We propose a method to calculate the canonical
partition function by fixing the total quark number introducing approximations
allowed in the low density region. An effective potential as a function of the
quark number density is discussed from the canonical partition function. We
analyze data obtained in a simulation of two-flavor QCD using p4-improved
staggered quarks with bare quark mass $m/T = 0.4$ on a $16^3 \times 4$ lattice.
The results suggest that the finite density phase transition at low temperature
is of first order.


title:
Hidden SDW order and effective low-energy theory for FeAs
  superconductors

abstract:
  We propose a simple effective model to describe FeAs superconductors. This
model is based on the assumption of a local spin-density-wave (SDW) order, with
its magnetization direction allowed to fluctuate. It is shown that the
long-range order with momentum Q=(\pi ,\pi) is generally unstable in competing
with the kinetic energy of the charge carriers. A true weak SDW order is formed
in the undoped case with an additional momentum shift Q_s=(\pi, 0) due to the
peculiar Fermi surface nesting. In the doped case, the unstable long-range
order driven by kinetic energy can naturally result in a d-wave superconducting
condensation. Such low-energy physics is protected by the presence of the local
SDW which sustains some kind of "Mott gags" for the multiband d-electrons near
the Fermi energy.


title: Non-perturbative moduli superpotential with positive exponents

abstract:
  We study non-perturbative moduli superpotentials with positive exponents,
i.e. the form like $Ae^{aT}$ with a positive constant $a$ and the modulus $T$.
These effects can be generated, e.g., by D-branes which have negative RR charge
of lower dimensional D-brane. The scalar potentials including such terms have a
quite rich structure. There are several local minima with different potential
energies and a high barrier, whose height is of ${\cal O}(M_p^4)$. We discuss
their implications from the viewpoints of cosmology and particle phenomenology,
e.g. the realization of inflation models, avoiding the overshooting problem.
This type of potentials would be useful to realize the inflation and low-energy
supersymmetry breaking.


title: A generalization of Ostrowski inequality on time scales for k points

abstract:
  In this paper we first generalize the Ostrowski inequality on time scales for
k points and then unify corresponding continuous and discrete versions. We also
point out some particular Ostrowski type inequalities on time scales as special
cases.


title: An Ostrowski-Gruss type inequality on time scales

abstract:
  In this paper we derive a new inequality of Ostrowski-Gruss type on time
scales and thus unify corresponding continuous and discrete versions. We also
apply our result to the quantum calculus case.


title: The geometry of determinant line bundles in noncommutative geometry

abstract:
  This paper is concerned with the study of the geometry of determinant line
bundles associated to families of spectral triples parametrized by the moduli
space of gauge equivalent classes of Hermitian connections on a Hermitian
finite projective module. We illustrate our results with some examples that
arise in noncommutative geometry.


title: A Note on Self-gravitating Radiation in AdS Spacetime

abstract:
  In this paper we investigate the equilibrium self-gravitating radiation in
higher dimensional, plane symmetric anti-de Sitter space. We find that there
exist essential differences from the spherically symmetric case: In each
dimension ($d\geq 4$), there are maximal mass (density), maximal entropy
(density) and maximal temperature configurations, they do not appear at the
same central energy density; the oscillation behavior appearing in the
spherically symmetric case, does not happen in this case; and the mass
(density), as a function of the central energy density, increases first and
reaches its maximum at a certain central energy density and then decreases
monotonically in $ 4\le d \le 7$, while in $d \geq 8$, besides the maximum, the
mass (density) of the equilibrium configuration has a minimum: the mass
(density) first increases and reaches its maximum, then decreases to its
minimum and then increases to its asymptotic value monotonically. The reason
causing the difference is discussed.


title: Technical Report - Automatic Contour Extraction from 2D Neuron Images

abstract:
  This work describes a novel methodology for automatic contour extraction from
2D images of 3D neurons (e.g. camera lucida images and other types of 2D
microscopy). Most contour-based shape analysis methods can not be used to
characterize such cells because of overlaps between neuronal processes. The
proposed framework is specifically aimed at the problem of contour following
even in presence of multiple overlaps. First, the input image is preprocessed
in order to obtain an 8-connected skeleton with one-pixel-wide branches, as
well as a set of critical regions (i.e., bifurcations and crossings). Next, for
each subtree, the tracking stage iteratively labels all valid pixel of
branches, up to a critical region, where it determines the suitable direction
to proceed. Finally, the labeled skeleton segments are followed in order to
yield the parametric contour of the neuronal shape under analysis. The reported
system was successfully tested with respect to several images and the results
from a set of three neuron images are presented here, each pertaining to a
different class, i.e. alpha, delta and epsilon ganglion cells, containing a
total of 34 crossings. The algorithms successfully got across all these
overlaps. The method has also been found to exhibit robustness even for images
with close parallel segments. The proposed method is robust and may be
implemented in an efficient manner. The introduction of this approach should
pave the way for more systematic application of contour-based shape analysis
methods in neuronal morphology.


title:
Constraining the mSUGRA parameter space using the entropy of dark matter
  halos

abstract:
  We derive an expression for the entropy of a dark matter halo described by a
Navarro-Frenk-White model with a core. The comparison of this entropy with the
one of dark matter at the freeze-out era allows us to constraint the parameter
space in mSUGRA models. Moreover, joining these constraints with the ones
obtained from the usual abundance criteria and demanding both criteria to be
consistent with the 2$\sigma$ bounds for the abundance of dark matter:
$0.112\leq\Omega_{DM}h^2\leq0.122$, we are able to clearly discriminate
validity regions among the values of $\tan \beta$, one of the parameters of the
mSUGRA model. We found that for the explored regions of the parameter space,
small values of tan$\beta$ are not favored; only for tan$\beta\simeq50$ are
both criteria significantly consistent. In the region where both criteria are
consistent we also found a lower bound for the neutralino mass, $m_{\chi}\geq
141$ GeV.


title: $\beta$-deformation for matrix model of M-theory

abstract:
  A new class of deformation of the matrix model of M-theory is considered. The
deformation is analogous to the so-called $\b$-deformation of $D=3+1$, $\mN=4$
Super Yang-Mills theory, which preserves the conformal symmetry. It is shown
that the deformed matrix model can be considered as a matrix model of M-theory
on a certain curved background in eleven-dimensional supergravity, under a
scaling limit involving the deformation parameter and $N$ (the size of the
matrices). The background belongs to the so-called pp-wave type metric with a
non-constant four-form flux depending linearly on transverse coordinates. Some
stable solutions of the deformed model are studied, which correspond to
membranes with the torus topology. In particular, it is found that apparently
distinct configurations of membranes, having different winding numbers, are
indistinguishable in the matrix model. Simultaneous introduction of both
$\b$-deformation and mass-deformation is also considered, and, in particular, a
situation is found in which the stable membrane configuration interpolates
between a torus and a sphere, depending on the values of the deformation
parameters.


title: Electronic Voting: the Devil is in the Details

abstract:
  Observing electronic voting from an international point of view gives some
perspective about its genesis and evolution. An analysis of the voting process
through its cultural, ontological, legal and political dimensions explains the
difficulty to normalize this process. It appears that international
organizations are not capable to properly defend the fundamental rights of the
citizens. The approach that was taken when DRE voting computers appeared seems
to have reoccured with VVAT voting computers and the european e-poll project.


title:
Analytical solutions of specific classes of astrophysical radiating
  shocks

abstract:
  In this paper we study specific classes of radiating shocks which are widely
spread in astrophysical environments. We present more general solutions of
their structure and proceed to the analytical determination of physical
quantities.


title: The economical SU(3)_C X SU(3)_L X U(1)_X model

abstract:
  In this report the SU(3)_C X SU(3)_L X U(1)_X gauge model with minimal scalar
sector, two Higgs triplets, is presented in detail. One of the vacuum
expectation values $u$ is a source of lepton-number violations and a reason for
mixing among charged gauge bosons--the standard model W^\pm and the bilepton
gauge bosons Y^\pm as well as among the neutral non-Hermitian bilepton X^0 and
neutral gauge bosons--the Z and the new Z'. An exact diagonalization of the
neutral gauge boson sector is derived and bilepton mass splitting is also
given. Because of these mixings, the lepton-number violating interactions exist
in both charged and neutral gauge boson sectors. Constraints on vacuum
expectation values of the model are estimated and u \simeq O(1) GeV, v \simeq
v_weak = 246 GeV, and \omega \simeq O(1) TeV. In this model there are three
physical scalars, two neutral and one charged, and eight Goldstone bosons--the
needed number for massive gauge bosons. The minimal scalar sector can provide
all fermions including quarks and neutrinos consistent masses in which some of
them require one-loop radiative corrections.


title: Loss in hybrid qubit-bus couplings and gates

abstract:
  We provide a characterization and analysis of the effects of dissipation on
oscillator assisted (qubus) quantum gates. The effects can be understood and
minimized by looking at the dynamics of the signal coherence and its
entanglement with the continuous variable probe. Adding loss in between
successive interactions we obtain the effective quantum operations, providing a
novel approach to loss analysis in such hybrid settings. We find that in the
presence of moderate dissipation the gate can operate with a high fidelity. We
also show how a simple iteration scheme leads to independent single qubit
dephasing, while retaining the conditional phase operation regardless of the
amount of loss incurred by the probe.


title: A Synthesizer Based on Frequency-Phase Analysis and Square Waves

abstract:
  This article introduces an effective generalization of the polar flavor of
the Fourier Theorem based on a new method of analysis. Under the premises of
the new theory an ample class of functions become viable as bases, with the
further advantage of using the same basis for analysis and reconstruction. In
fact other tools, like the wavelets, admit specially built nonorthogonal bases
but require different bases for analysis and reconstruction (biorthogonal and
dual bases) and vectorial coordinates; this renders those systems unintuitive
and computing intensive. As an example of the advantages of the new
generalization of the Fourier Theorem, this paper introduces a novel method for
the synthesis that is based on frequency-phase series of square waves (the
equivalent of the polar Fourier Theorem but for nonorthogonal bases). The
resulting synthesizer is very efficient needing only few components, frugal in
terms of computing needs, and viable for many applications.


title:
Fundamental classes of negatively curved manifolds cannot be represented
  by products of manifolds

abstract:
  Not every singular homology class is the push-forward of the fundamental
class of some manifold. In the same spirit, one can study the following
problem: Which singular homology classes are the push-forward of the
fundamental class of a given type of manifolds? In the present article, we show
that the fundamental classes of negatively curved manifolds cannot be
represented by a non-trivial product of manifolds. This observation sheds some
light on the functorial semi-norm on singular homology given by products of
compact surfaces.


title: A Conversation with Seymour Geisser

abstract:
  Seymour Geisser received his bachelor's degree in Mathematics from the City
College of New York in 1950, and his M.A. and Ph.D. degrees in Mathematical
Statistics at the University of North Carolina in 1952 and 1955, respectively.
He then held positions at the National Bureau of Standards and the National
Institute of Mental Health until 1961. From 1961 until 1965, he was Chief of
the Biometry Section at the National Institute of Arthritis and Metabolic
Diseases, and also held the position of Professorial Lecturer at the George
Washington University from 1960 to 1965. From 1965 to 1970, he was the founding
Chair of the Department of Statistics at the State University of New York,
Buffalo, and in 1971, he became the founding Director of the School of
Statistics at the University of Minnesota, remaining in that position until
2001. He held visiting professorships at Iowa State University, 1960;
University of Wisconsin, 1964; University of Tel-Aviv (Israel), 1971;
University of Waterloo (Canada), 1972; Stanford University, 1976, 1977, 1988;
Carnegie Mellon University, 1976; University of the Orange Free State (South
Africa), 1978, 1993; Harvard University, 1981; University of Chicago, 1985;
University of Warwick (England), 1986; University of Modena (Italy), 1996; and
National Chiao Tung University (Taiwan), 1998. He was the Lady Davis Visiting
Professor, Hebrew University of Jerusalem, 1991, 1994, 1999, and the Schor
Scholar, Merck Research Laboratories, 2002-2003. He was a Fellow of the
Institute of Mathematical Statistics and the American Statistical Association.


title: A Conversation with Monroe Sirken

abstract:
  Born January 11, 1921 in New York City, Monroe Sirken grew up in a suburb of
Pasadena, California. He earned B.A. and M.A. degrees in sociology at UCLA in
1946 and 1947, and a Ph.D. in 1950 in sociology with a minor in mathematics at
the University of Washington in 1950 where Professor Z. W. Birnbaum was his
mentor and thesis advisor. As a Post-Doctoral Fellow of the Social Science
Research Council, Monroe spent 1950--1951 at the Statistics Laboratory,
University of California at Berkeley and the Office of the Assistant Director
for Research, U.S. Bureau of the Census in Suitland, Maryland. Monroe visited
the Census Bureau at a time of great change in the use of sampling and survey
methods, and decided to remain. He began his government career there in 1951 as
a mathematical statistician, and moved to the National Office of Vital
Statistics (NOVS) in 1953 where he was an actuarial mathematician and a
mathematical statistician. He has held a variety of research and administrative
positions at the National Center for Health Statistics (NCHS) and he was the
Associate Director, Research and Methodology and the Director, Office of
Research and Methodology until 1996 when he became a senior research scientist,
the title he currently holds. Aside from administrative responsibilities,
Monroe's major professional interests have been conducting and fostering survey
and statistical research responsive to the needs of federal statistics. His
interest in the design of rare and sensitive population surveys led to the
development of network sampling which improves precision by linking multiple
selection units to the same observation units. His interest in fostering
research on the cognitive aspects of survey methods led to the establishment of
permanent questionnaire design research laboratories, first at NCHS and later
at other federal statistical agencies here and abroad.


title: Intensity of parametric fluorescence pumped by ultrashort pulses

abstract:
  We investigate intensity of the parametric down conversion of ultrashort,
ultraviolet pulse both in a low- and high-conversion regime. In the first
regime, we develop a simple analytical expressions for the photon flux of the
fluorescence. Numerical simulations using three-dimensional stochastic Wigner
method provide results in the latter regime. We find that the perturbative
approximation for the photon flux as a function of the wavelength of the signal
and the observation angle, quantitatively describes even the non-perturbative
regime. For short pump pulses the intensity of the fluorescence is highest at
frequencies where the group velocities of the pump and the down-conversion are
equal. For longer pump pulses this requirement is gradually relaxed.
Additionally, for small pump beams, the intensity strongly depends on the
spatial divergence between interacting fields.


title: Wandering in five-dimensional curved superspace

abstract:
  This is a brief review of the superspace formulation for five-dimensional N=1
matter-coupled supergravity recently developed by the authors.


title: Probing protoneutron star density profile from neutrino signals

abstract:
  Supernovae of Type II is a phenomenon that occurs at the end of evolution of
massive stars when the iron core of the star exceeds a mass limit. After
collapse of the core under gravity the shock wave alone does not succeed in
expelling the mass of the star and in this sense the role of neutrinos is the
most important mechanism to do so. During the emission of neutrinos flavor
conversion is possible, related the phenomenon of oscillations, which however
depends directly on the particular density profile of the medium. In this paper
we present results of numerical simulations of neutrino flavor conversion in
protoneutron stars and after collapse. The probabilities of survival for a
given flavor in a complete three-flavors framework is estimated through an
algorithm which conserves unitarity to a high degree of accuracy. The
sensitivity of the results to the different adopted models for the protoneutron
star structure is examined in detail demonstrating how the neutrino signal
could be used to check the validity of models.


title: On-orbit Performance of the Solar Optical Telescope aboard Hinode

abstract:
  On-orbit performance of the Solar Optical Telescope (SOT) aboard Hinode is
described with some attentions on its unpredicted aspects. In general, SOT
revealed an excellent performance and has been providing outstanding data. Some
unexpected features exist, however, in behaviors of the focus position,
throughput and structural stability. Most of them are recovered by the daily
operation i.e., frequent focus adjustment, careful heater setting and
corrections in data analysis. The tunable filter contains air bubbles which
degrade the data quality significantly. Schemes for tuning the filter without
disturbing the bubbles have been developed and tested, and some useful
procedures to obtain Dopplergram and magnetogram are now available. October and
March when the orbit of satellite becomes nearly perpendicular to the direction
towards the sun provide a favorable condition for continuous runs of the
narrow-band filter imager.


title:
Precision calculations of the gravitational wave background spectrum
  from inflation

abstract:
  The spectrum of the gravitational wave background originating from quantum
fluctuations during inflation is calculated numerically for various inflation
models over a wide range of frequencies. We take into account four ingredients
: the scalar field dynamics during inflation making no use of the slow-roll
approximation, the fermionic decay of the scalar field with a small coupling
constant during the reheating process, the change of the effective number of
degrees of freedom g_* in the radiation-dominated era, and the anisotropic
stress of free-streaming neutrinos. By numerically solving the evolution of
gravitational waves during and after inflation up to the present, all of these
effects can be examined comprehensively and accurately over a broad spectrum,
even at very high frequencies. We find that the spectrum shows (i) a large
deviation from the spectrum less accurate obtained by Taylor expanding around
the CMB scale using the slow-roll approximation (ii) a characteristic frequency
dependence due to the reheating effect, and (iii) damping due to the g_*
changes and the neutrino anisotropic stress. We suggest that future analysis of
the gravitational wave background should take into consideration the fact that
analytical estimates using the Taylor expansion overestimate the amplitude of
the spectrum.


title: CeFePO: A Heavy Fermion Metal with Ferromagnetic Correlations

abstract:
  The ground state properties of CeFePO, a homologue of the new high
temperature superconductors RFePnO(1-x)Fx, were studied by means of
susceptibility, specific heat, resistivity, and NMR measurements on
polycrystals. All the results demonstrate that this compound is a magnetically
non-ordered heavy Fermion metal with a Kondo temperature TK~10K, a Sommerfeld
coefficient gamma=700mJ/molK2 and a mass enhancement factor of the order of
200. The absence of a Fe-contribution to the effective moment at high
temperatures indicates that the magnetism in CeFePO is completely dominated by
the effect of Ce. Thus the strong electronic correlation effects originate from
the Ce-4f electrons rather than from the Fe-3d electrons. An enhanced
Sommerfeld-Wilson ratio R=5.5 as well as a Korringa product S0/T1TK2~0.065 well
below 1 indicate the presence of ferromagnetic correlations. Therefore, CeFePO
appears to be on the non-magnetic side of a ferromagnetic instability.


title:
Heavy Flavor decays and light hadrons in the FOCUS experiment: recent
  results

abstract:
  Interpretation of D-meson decay-dynamics has revealed itself to be strongly
dependent on our understanding of the light-meson sector. The interplay becomes
particularly evident in Dalitz plot analyses to study physics within and beyond
the Standard Model. Experience and results from FOCUS are presented and
discussed. A brief update of the pentaquark search in the experiment is also
reported.


title: Poisson type generators for L^1(R)

abstract:
  We characterize the discrete sets L of the real line such that {f(t-l), l in
L} span L^1(R), f being an L^1(R)-function whose Fourier transform behaves like
the one of the Poisson function.


title: Oscillations in Beta UMi - Observations with SMEI

abstract:
  Aims: From observations of the K4III star Beta UMi we attempt to determine
whether oscillations or any other form of variability is present.
  Methods: A high-quality photometric time series of approximately 1000 days in
length obtained from the SMEI instrument on the Coriolis satellite is analysed.
Various statistical tests were performed to determine the significance of
features seen in the power density spectrum of the light curve.
  Results: Two oscillations with frequencies 2.44 and 2.92 microhertz have been
identified. We interpret these oscillations as consecutive overtones of an
acoustic spectrum, implying a large frequency spacing of 0.48 microhertz. Using
derived asteroseismic parameters in combination with known astrophysical
parameters, we estimate the mass of Beta UMi to be 1.3 +/- 0.3 solar masses.
Peaks of the oscillations in the power density spectrum show width, implying
that modes are stochastically excited and damped by convection. The mode
lifetime is estimated at 18 +/- 9 days.


title: Model spaces results for the Gabor and Wavelet transforms

abstract:
  We prove that the unique Gabor atom with analytical model space is the
Gaussian function. We give an analogous result for the wavelet transform. For
the general case we give a new approach to study the irregular Gabor and
wavelet frames. We improve some results for Gabor atoms in the Feichtinger
algebra, and for a special class of wavelets.


title: Reconstruction of Multidimensional Signals from Irregular Noisy Samples

abstract:
  We focus on a multidimensional field with uncorrelated spectrum, and study
the quality of the reconstructed signal when the field samples are irregularly
spaced and affected by independent and identically distributed noise. More
specifically, we apply linear reconstruction techniques and take the mean
square error (MSE) of the field estimate as a metric to evaluate the signal
reconstruction quality. We find that the MSE analysis could be carried out by
using the closed-form expression of the eigenvalue distribution of the matrix
representing the sampling system. Unfortunately, such distribution is still
unknown. Thus, we first derive a closed-form expression of the distribution
moments, and we find that the eigenvalue distribution tends to the
Marcenko-Pastur distribution as the field dimension goes to infinity. Finally,
by using our approach, we derive a tight approximation to the MSE of the
reconstructed field.


title: Search for high velocities in the disk counterpart of type II spicules

abstract:
  Recently, De Pontieu et al. (2007b) discovered a class of spicules that
evolves more rapidly than previously known spicules, with rapid apparent
motions of 50--150 km s${}^{-1}$, thickness of a few 100 km, and lifetimes of
order 10--60 seconds. These so-called type II spicules have been difficult to
study because of limited spatio-temporal and thermal resolution. Here we use
the IBIS instrument to search for the high velocities in the disk counterpart
of type II spicules. We have detected rapidly evolving events, with lifetimes
that are less than a minute and often equal to the cadence of the instrument
(19 secs). These events are characterized by a Doppler shift that only appears
in the blue wing of the Ca II IR line. Furthermore the spatial extent,
lifetime, and location near network, all suggest a link to type II spicules.
However, the magnitude of the measured Doppler velocity is significantly lower
than the apparent motions seen at the limb. We use Monte Carlo simulations to
show that this discrepancy can be explained by a forward model in which the
visibility on the disk of the high-velocity flows in these events is limited by
a combination of line-of-sight projection and reduced opacity in upward
propelled plasma, especially in reconnection driven jets that are powered by a
roughly constant energy supply.


title:
Spatial entanglement of paired photons generated in cold atomic
  ensembles

abstract:
  Cold atomic ensembles can mediate the generation of entanglement between
pairs of photons. Photons with specific directions of propagation are detected,
and the entanglement can reside in any of the degrees of freedom that describe
the whole quantum state of the photons: polarization, spatial shape or
frequency. We show that the direction of propagation of the generated photons
determines the spatial quantum state of the photons and therefore, the amount
of entanglement generated. When photons generated in different directions are
combined, this spatial distinguishing information can degrade the quantum
purity of the polarization or frequency entanglement.


title: Torus fibrations and localization of index I

abstract:
  We define a local Riemann-Roch number for an open symplectic manifold when a
complete integrable system without Bohr-Sommerfeld fiber is provided on its
end. In particular when a structure of a singular Lagrangian fibration is given
on a closed symplectic manifold, its Riemann-Roch number is described as the
sum of the number of nonsingular Bohr-Sommerfeld fibers and a contribution of
the singular fibers. A key step of the proof is formally explained as a version
of Witten's deformation applied to a Hilbert bundle.


title:
On Multiuser Power Region of Fading Multiple-Access Channel with
  Multiple Antennas

abstract:
  This paper is concerned with the fading MIMO-MAC with multiple receive
antennas at the base station (BS) and multiple transmit antennas at each mobile
terminal (MT). Two multiple-access techniques are considered for scheduling
transmissions from each MT to the BS at the same frequency, which are
space-division multiple-access (SDMA) and time-division multiple-access (TDMA).
For SDMA, all MTs transmit simultaneously to the BS and their individual
signals are resolved at the BS via multiple receive antennas while for TDMA,
each MT transmits independently to the BS during mutually orthogonal time
slots. It is assumed that the channel-state information (CSI) of the fading
channel from each MT to the BS is unknown at each MT transmitter, but is
perfectly known at the BS receiver. Thereby, the BS can acquire the long-term
channel-distribution information (CDI) for each MT. This paper extends the
well-known transmit-covariance feedback scheme for the point-to-point fading
MIMO channel to the fading MIMO-MAC, whereby the BS jointly optimizes the
transmit signal covariance matrices for all MTs based on their CDI, and then
sends each transmit covariance matrix back to the corresponding MT via a
feedback channel. The main goal of this paper is to characterize the so-called
multiuser power region under the multiuser transmit-covariance feedback scheme
for both SDMA and TDMA. The power region is defined as the constitution of all
user transmit power-tuples that can achieve reliable transmissions for a given
set of user target rates. Simulation results show that SDMA can achieve
substantial power savings over TDMA for the fading MIMO-MAC. Moreover, this
paper demonstrates the usefulness of the multiuser power region for maintaining
proportionally-fair power consumption among the MTs.


title: Milnor $K$-group attached to a torus and Birch-Tate conjecture

abstract:
  We formulate (and prove under a certain assumption) a conjecture relating the
order of Somekawa's Milnor $K$-group attached to a torus $T$ and the value of
the Artin $L$-function attached to the cocharacter group of $T$ (regarded as an
Artin representation) at $s=-1$. The case $T=\G_m$ reduces to the classical
Birch-Tate conjecture.


title:
Optimal Dynamic Resource Allocation for Multi-Antenna Broadcasting with
  Heterogeneous Delay-Constrained Traffic

abstract:
  This paper is concerned with dynamic resource allocation in a cellular
wireless network with slow fading for support of data traffic having
heterogeneous transmission delay requirements. The multiple-input single-output
(MISO) fading broadcast channel (BC) is of interest where the base station (BS)
employs multiple transmit antennas to realize simultaneous downlink
transmission at the same frequency to multiple mobile users each having a
single receive antenna. An information-theoretic approach is taken for
characterizing capacity limits of the fading MISO-BC under various transmission
delay considerations. First, this paper studies transmit optimization at the BS
when some users have delay-tolerant ``packet'' data and the others have
delay-sensitive ``circuit'' data for transmission at the same time. Based on
the convex optimization framework, an online resource allocation algorithm is
derived that is amenable to efficient cross-layer implementation of both
physical (PHY) -layer multi-antenna transmission and media-access-control (MAC)
-layer multiuser rate scheduling. Secondly, this paper investigates the
fundamental throughput-delay tradeoff for transmission over the fading MISO-BC.
By comparing the network throughput under completely relaxed versus strictly
zero transmission delay constraint, this paper characterizes the limiting loss
in sum capacity due to the vanishing delay tolerance, termed the delay penalty,
under some prescribed user fairness for transmit rate allocation.


title: Mesoscopic study on historic masonry

abstract:
  This paper presents a comprehensive approach to the evaluation of macroscopic
material parameters for natural stone and quarry masonry. To that end, a
reliable non-linear material model on a meso-scale is developed to cover the
random arrangement of stone blocks and quasi-brittle behaviour of both basic
components, as well as the impaired cohesion and tensile strength on the
interface between the blocks and mortar joints. The paper thus interrelates the
following three problems: (i) definition of a suitable periodic unit cell (PUC)
representing a particular masonry structure; (ii) derivation of material
parameters of individual constituents either experimentally or running a mixed
numerical-experimental problem; (iii) assessment of the macroscopic material
parameters including the tensile and compressive strengths and fracture energy.


title: Lifts of matroid representations over partial fields

abstract:
  There exist several theorems which state that when a matroid is representable
over distinct fields F_1,...,F_k, it is also representable over other fields.
We prove a theorem, the Lift Theorem, that implies many of these results.
  First, parts of Whittle's characterization of representations of ternary
matroids follow from our theorem. Second, we prove the following theorem by
Vertigan: if a matroid is representable over both GF(4) and GF(5), then it is
representable over the real numbers by a matrix such that the absolute value of
the determinant of every nonsingular square submatrix is a power of the golden
ratio. Third, we give a characterization of the 3-connected matroids having at
least two inequivalent representations over GF(5). We show that these are
representable over the complex numbers.
  Additionally we provide an algebraic construction that, for any set of fields
F_1,...,F_k, gives the best possible result that can be proven using the Lift
Theorem.


title:
Area spectrum of rotating black holes via the new interpretation of
  quasinormal modes

abstract:
  Motivated by the recent work on a new physical interpretation of quasinormal
modes by Maggiore, we utilize this new proposal to the interesting case of Kerr
black hole. In particular, by modifying Hod's idea, the resulting black hole
horizon area is quantized and the resulting area quantum is in full agreement
with Bekenstein's result. Furthermore, in an attempt to show that the area
spectrum is equally spaced, we follow Kunstatter's method. We propose a new
interpretation as a result of Maggiore's idea, for the frequency that appears
in the adiabatic invariant of a black hole. The derived area spectrum is
similar to that of the quantum-corrected Kerr black hole but it is not equally
spaced.


title: E2 Instanton Effects and Higgs Physics In Intersecting Brane Models

abstract:
  String instanton effects in Higgs physics are discussed through a type IIA
model based on T^{6}/(Z^{2}\times Z^{'2}) orentifold compactifaction. By
inclusion of rigid E2-branes, the model exhibits a MSSM-like spectrum, as well
as extra mu and quartic Higgs couplings. These extra couplings are induced via
E2 instantons non-perturbatively. Setting the string scale at 10^{18} GeV, one
gets interesting TeV Higgs physics. In particlular, the tree-level Higgs mass
can be uplifted substantially.


title: Wadge Degrees of Infinitary Rational Relations

abstract:
  We show that, from the topological point of view, 2-tape B\"uchi automata
have the same accepting power as Turing machines equipped with a B\"uchi
acceptance condition. The Borel and the Wadge hierarchies of the class
RAT_omega of infinitary rational relations accepted by 2-tape B\"uchi automata
are equal to the Borel and the Wadge hierarchies of omega-languages accepted by
real-time B\"uchi 1-counter automata or by B\"uchi Turing machines. In
particular, for every non-null recursive ordinal $\alpha$, there exist some
$\Sigma^0_\alpha$-complete and some $\Pi^0_\alpha$-complete infinitary rational
relations. And the supremum of the set of Borel ranks of infinitary rational
relations is an ordinal $\gamma^1_2$ which is strictly greater than the first
non-recursive ordinal $\omega_1^{CK}$. This very surprising result gives
answers to questions of Simonnet (1992) and of Lescow and Thomas (1988,1994).


title: Giant magnons in the D1-D5 system

abstract:
  We study giant magnons in the the D1-D5 system from both the boundary CFT and
as classical solutions of the string sigma model in $AdS_3\times S^3\times
T^4$. Re-examining earlier studies of the symmetric product conformal field
theory we argue that giant magnons in the symmetric product are BPS states in a
centrally extended $SU(1|1)\times SU(1|1)$ superalgebra with two more
additional central charges. The magnons carry these additional central charges
locally but globally they vanish. Using a spin chain description of these
magnons and the extended superalgebra we show that these magnons obey a
dispersion relation which is periodic in momentum. We then identify these
states on the string theory side and show that here too they are BPS in the
same centrally extended algebra and obey the same dispersion relation which is
periodic in momentum. This dispersion relation arises as the BPS condition for
the extended algebra and is similar to that of magnons in ${\cal N}=4$
Yang-Mills


title: Modulated inflation from kinetic term

abstract:
  We study modulated inflation from kinetic term. Using the Mukhanov-Sasaki
variable, it is possible to determine how mixing induced by the kinetic term
feeds the curvature perturbation with the isocurvature perturbation. We show
explicitly that the analytic result obtained from the evolution of the
Mukhanov-Sasaki variable is consistent with the $\delta N$-formula. From our
results, we find analytic conditions for the modulated fluctuation and the
non-Gaussianity parameter.


title: Phoneme recognition in TIMIT with BLSTM-CTC

abstract:
  We compare the performance of a recurrent neural network with the best
results published so far on phoneme recognition in the TIMIT database. These
published results have been obtained with a combination of classifiers.
However, in this paper we apply a single recurrent neural network to the same
task. Our recurrent neural network attains an error rate of 24.6%. This result
is not significantly different from that obtained by the other best methods,
but they rely on a combination of classifiers for achieving comparable
performance.


title:
Transition from phase to generalized synchronization in time-delay
  systems

abstract:
  The notion of phase synchronization in time-delay systems, exhibiting highly
non-phase-coherent attractors, has not been realized yet even though it has
been well studied in chaotic dynamical systems without delay. We report the
identification of phase synchronization in coupled nonidentical piece-wise
linear and in coupled Mackey-Glass time-delay systems with highly
non-phase-coherent regimes. We show that there is a transition from
non-synchronized behavior to phase and then to generalized synchronization as a
function of coupling strength. We have introduced a transformation to capture
the phase of the non-phase coherent attractors, which works equally well for
both the time-delay systems. The instantaneous phases of the above coupled
systems calculated from the transformed attractors satisfy both the phase and
mean frequency locking conditions. These transitions are also characterized in
terms of recurrence based indices, namely generalized autocorrelation function
$P(t)$, correlation of probability of recurrence (CPR), joint probability of
recurrence (JPR) and similarity of probability of recurrence (SPR). We have
quantified the different synchronization regimes in terms of these indices. The
existence of phase synchronization is also characterized by typical transitions
in the Lyapunov exponents of the coupled time-delay systems.


title: Information Theoretic Operating Regimes of Large Wireless Networks

abstract:
  In analyzing the point-to-point wireless channel, insights about two
qualitatively different operating regimes--bandwidth- and power-limited--have
proven indispensable in the design of good communication schemes. In this
paper, we propose a new scaling law formulation for wireless networks that
allows us to develop a theory that is analogous to the point-to-point case. We
identify fundamental operating regimes of wireless networks and derive
architectural guidelines for the design of optimal schemes.
  Our analysis shows that in a given wireless network with arbitrary size,
area, power, bandwidth, etc., there are three parameters of importance: the
short-distance SNR, the long-distance SNR, and the power path loss exponent of
the environment. Depending on these parameters we identify four qualitatively
different regimes. One of these regimes is especially interesting since it is
fundamentally a consequence of the heterogeneous nature of links in a network
and does not occur in the point-to-point case; the network capacity is {\em
both} power and bandwidth limited. This regime has thus far remained hidden due
to the limitations of the existing formulation. Existing schemes, either
multihop transmission or hierarchical cooperation, fail to achieve capacity in
this regime; we propose a new hybrid scheme that achieves capacity.


title:
Local electronic structure of Cr in the II-VI diluted ferromagnetic
  semiconductor Zn$_{1-x}$Cr$_x$Te

abstract:
  The electronic structure of the Cr ions in the diluted ferromagnetic
semiconductor Zn$_{1-x}$Cr$_x$Te ($x=0.03$ and 0.15) thin films has been
investigated using x-ray magnetic circular dichroism (XMCD) and photoemission
spectroscopy (PES). Magnetic-field ($H$) and temperature ($T$) dependences of
the Cr $2p$ XMCD spectra well correspond to the magnetization measured by a
SQUID magnetometer. The line shape of the Cr $2p$ XMCD spectra is independent
of $H$, $T$, and $x$, indicating that the ferromagnetism is originated from the
same electronic states of the Cr ion. Cluster-model analysis indicates that
although there are two or more kinds of Cr ions in the Zn$_{1-x}$Cr$_x$Te
samples, the ferromagnetic XMCD signal is originated from Cr ions substituted
for the Zn site. The Cr 3d partial density of states extracted using Cr $2p \to
3d$ resonant PES shows a broad feature near the top of the valence band,
suggesting strong $s$,$p$-$d$ hybridization. No density of states is detected
at the Fermi level, consistent with their insulating behavior. Based on these
findings, we conclude that double exchange mechanism cannot explain the
ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te.


title: Giant electro-optic effect using polarizable dark states

abstract:
  The electro-optic effect, where the refractive index of a medium is modified
by an electric field, is of central importance in non-linear optics, laser
technology, quantum optics and optical communications. In general,
electro-optic coefficients are very weak and a medium with a giant
electro-optic coefficient would have profound implications for non-linear
optics, especially at the single photon level, enabling single photon
entanglement and switching. Here we propose and demonstrate a giant
electro-optic effect based on polarizable dark states. We demonstrate phase
modulation of the light field in the dark state medium and measure an
electro-optic coefficient that is more than 12 orders of magnitude larger than
in other gases. This enormous Kerr non-linearity also creates the potential for
precision electrometry and photon entanglement.


title:
A hierarchical search for gravitational waves from supermassive black
  hole binary mergers

abstract:
  We present a method to search for gravitational waves from coalescing
supermassive binary black holes in LISA data. The search utilizes the
$\mathcal{F}$-statistic to maximize over, and determine the values of, the
extrinsic parameters of the binary system. The intrinsic parameters are
searched over hierarchically using stochastically generated multi-dimensional
template banks to recover the masses and sky locations of the binary. We
present the results of this method applied to the mock LISA data Challenge 1B
data set.


title: The relevance of neck linker docking in the motility of kinesin

abstract:
  Conventional kinesin is a motor protein, which is able to walk along a
microtubule processively. The exact mechanism of the stepping motion and force
generation of kinesin is still far from clear. In this paper we argue that neck
linker docking is a crucial element of this mechanism, without which the
experimentally observed dwell times of the steps could not be explained under a
wide range of loading forces. We also show that the experimental data impose
very strict constraints on the lengths of both the neck linker and its docking
section, which are compatible with the known structure of kinesin.


title: A Concise Introduction to Perturbation Theory in Cosmology

abstract:
  We give a concise, self-contained introduction to perturbation theory in
cosmology at linear and second order, striking a balance between mathematical
rigour and usability. In particular we discuss gauge issues and the active and
passive approach to calculating gauge transformations. We also construct
gauge-invariant variables, including the second order tensor perturbation on
uniform curvature hypersurfaces.


title: Optimal stopping for L\'evy processes and affine functions

abstract:
  This paper studies an optimal stopping problem for L\'evy processes. We give
a justification of the form of the Snell envelope using standard results of
optimal stopping. We also justify the convexity of the value function, and
without a priori restriction to a particular class of stopping times, we deduce
that the smallest optimal stopping time is necessarily a hitting time. We
propose a method which allows to obtain the optimal threshold. Moreover this
method allows to avoid long calculations of the integro-differential
operatorused in the usual proofs.


title: Gravitational wave generation in power-law inflationary models

abstract:
  We investigate the generation of gravitational waves in power-law
inflationary models. The energy spectrum of the gravitational waves is
calculated using the method of continuous Bogoliubov coefficients. We show
that, by looking at the interval of frequencies between 10^(-5) and 10^5 Hz and
also at the GHz range, important information can be obtained, both about the
inflationary period itself and about the thermalization regime between the end
of inflation and the beginning of the radiation-dominated era. We thus deem the
development of gravitational wave detectors, covering the MHz/GHz range of
frequencies, to be an important task for the future.


title:
The Effect of Recombination on the Neutral Evolution of Genetic
  Robustness

abstract:
  Conventional population genetics considers the evolution of a limited number
of genotypes corresponding to phenotypes with different fitness. As model
phenotypes, in particular RNA secondary structure, have become computationally
tractable, however, it has become apparent that the context dependent effect of
mutations and the many-to-one nature inherent in these genotype-phenotype maps
can have fundamental evolutionary consequences. It has previously been
demonstrated that populations of genotypes evolving on the neutral networks
corresponding to all genotypes with the same secondary structure only through
neutral mutations can evolve mutational robustness [Nimwegen {\it et al.}
Neutral evolution of mutational robustness, 1999 PNAS], by concentrating the
population on regions of high neutrality. Introducing recombination we
demonstrate, through numerically calculating the stationary distribution of an
infinite population on ensembles of random neutral networks that mutational
robustness is significantly enhanced and further that the magnitude of this
enhancement is sensitive to details of the neutral network topology. Through
the simulation of finite populations of genotypes evolving on random neutral
networks and a scaled down microRNA neutral network, we show that even in
finite populations recombination will still act to focus the population on
regions of locally high neutrality.


title: Interband physics in an ultra-cold Fermi gas in an optical lattice

abstract:
  We study a gas of strongly polarized cold fermions in an optical lattice when
the excited p-bands are populated. We derive the relevant Hamiltonian and
discuss the expected phase diagram for both repulsive and attractive
interactions. In the parameter regime covered here, checkerboard
anti-ferromagnetic ordering is found to be possible for repulsive interactions
while for attractive interactions, transitions between different types of
paired phases are predicted.


title:
Temperature dependence of evaporation coeffcient of water in air and
  nitrogen under atmospheric pressure; study in water droplets

abstract:
  The evaporation coefficients of water in air and nitrogen were found as a
function of temperature, by studying the evaporation of pure water droplet. The
droplet was levitated in an electrodynamic trap placed in a climatic chamber
maintaining atmospheric pressure. Droplet radius evolution and evaporation
dynamics were studied with high precision by analyzing the angle-resolved light
scattering Mie interference patterns. A model of quasi-stationary droplet
evolution, accounting for the kinetic effects near the droplet surface was
applied. In particular, the effect of thermal effusion (a short range analogue
of thermal diffusion) was discussed and accounted for. The evaporation
coefficient \alpha in air and in nitrogen were found equal. \alpha was found to
decrease from ~ 0.18 to ~ 0.13 for the temperature range from 273.1 K to 293.1
K and follow the trend given by Arrhenius formula. The agreement with
condensation coefficient values obtained with essentially different method by
Li et al.[1] was found excellent. The comparison of experimental conditions
used in both methods revealed no dependence of evaporation/condensation
coefficient upon droplet charge nor ambient gas pressure within experimental
parameters range. The average value of thermal accommodation coefficient over
the same temperature range was found to be 1 \pm 0.05.


title: CKM matrix unitarity and a novel type of global fits

abstract:
  The aim of the paper is to propose one paradigm change of CKM global fits on
experimental data from electroweak sector. The change refers to using in fits
the exact unitarity constraints expressed in terms of four invariant
parameters, such as moduli of the CKM matrix, and to take into account an
important set of the available experimental data. In the paper we use data from
nuclear beta decays, and from leptonic and semileptonic decays, in order to
find the most probable numerical form of the CKM matrix, as well as the
determination of decay constants, $f_{P}$, and of various form factors
$f_+^{Pp}(0)$, directly from experimental results.


title: Coulomb correlation effects in LaOFeAs: LDA+DMFT(QMC) study

abstract:
  Effects of Coulomb correlation on LaOFeAs electronic structure have been
investigated by LDA+DMFT(QMC) method. The calculation results show that LaOFeAs
is in the regime of intermediate correlation strength with significant part of
the spectral density moved from the Fermi energy to Hubbard bands. However the
system is not on the edge of metal insulator-transition because increase of the
Coulomb interaction parameter value from $U$=4.0 eV to $U$=5.0 eV did not
result in insulator state. Correlations affect different d-orbitals not in the
same way. $t_{2g}$ states ($xz,yz$ and $x^2-y^2$ orbitals) have higher energy
due to crystal filed splitting and are nearly half-filled. Their spectral
functions have pseudogap with Fermi energy position on the higher sub-band
slope. Lower energy $e_g$ set of d-orbitals ($3z^2-r^2$ and $xy$) have
significantly larger occupancy values with typically metallic spectral
functions.


title: Phase separation in fermionic systems with particle-hole asymmetry

abstract:
  We determine the ground-state phase-diagram of a Hubbard Hamiltonian with
correlated hopping, which is asymmetric under particle-hole transform. By
lowering the repulsive Coulomb interaction U at appropriate filling and
interaction parameters, the ground state separates into a hole and an electron
conducting phases: two different wave vectors characterize the system and
charge-charge correlations become incommensurate. By further decreasing U
another transition occurs at which the hole conducting region becomes
insulating, and conventional phase separation takes place. Finally, for
negative U the whole system eventually becomes a paired insulator. It is
speculated that such behavior could be at the origin of the incommensurate
superconducting phase recently discovered in the 1D Hirsch model. The exact
phase boundaries are calculated in one dimension.


title:
Charged Dilaton, Energy, Momentum and Angular-Momentum in Teleparallel
  Theory Equivalent to General Relativity

abstract:
  We apply the energy-momentum tensor to calculate energy, momentum and
angular-momentum of two different tetrad fields. This tensor is coordinate
independent of the gravitational field established in the Hamiltonian structure
of the teleparallel equivalent of general relativity (TEGR). The spacetime of
these tetrad fields is the charged dilaton. Our results show that the energy
associated with one of these tetrad fields is consistent, while the other one
does not show this consistency. Therefore, we use the regularized expression of
the gravitational energy-momentum tensor of the TEGR. We investigate the energy
within the external event horizon using the definition of the gravitational
energy-momentum.


title:
A characterization of double covers of curves in terms of the ample cone
  of second symmetric product

abstract:
  We investigate the nef cone spanned by the diagonal and the fibre classes of
second symmetric product of a curve of genus $g$. This 2-dimensional nef cone
gives a characterization of double covers of curves of genus $\le
\frac{g-1}{8}$. This is a generalization of a result by Debarre.


title: Double barrier potentials for matter-wave gap solitons

abstract:
  We investigate collisions of solitons of the gap type, supported by a lattice
potential in repulsive Bose-Einstein condensates, with an effective
double-barrier potential that resembles a Fabry-Perot cavity. We identify
conditions under which the trapping of the entire incident soliton in the
cavity is possible. Collisions of the incident soliton with an earlier trapped
one are considered too. In the latter case, many outcomes of the collisions are
identified, including merging, release of the trapped soliton with or without
being replaced by the incoming one, and trapping of both solitons.


title:
Simulation of stochastic reaction-diffusion processes on unstructured
  meshes

abstract:
  Stochastic chemical systems with diffusion are modeled with a
reaction-diffusion master equation. On a macroscopic level, the governing
equation is a reaction-diffusion equation for the averages of the chemical
species. On a mesoscopic level, the master equation for a well stirred chemical
system is combined with Brownian motion in space to obtain the
reaction-diffusion master equation. The space is covered by an unstructured
mesh and the diffusion coefficients on the mesoscale are obtained from a finite
element discretization of the Laplace operator on the macroscale. The resulting
method is a flexible hybrid algorithm in that the diffusion can be handled
either on the meso- or on the macroscale level. The accuracy and the efficiency
of the method are illustrated in three numerical examples inspired by molecular
biology.


title: Principal basis in Cartan subalgebra

abstract:
  Let $\Lie{g}$ be a simple complex Lie algebra and $\Lie{h}$ a Cartan
subalgebra. In this article we explain how to obtain the principal basis of
$\Lie{h}$ starting form a set of generators
$\{p_1,...,p_r\}$,$r=\rank(\Lie{g})$, of the invariants polynomials $\Sgg$. For
each invariant polynomial $p$, we define a $G$-equivariant map $Dp$ form
$\Lie{g}$ to $\Lie{g}$. We show that the Gram-Schmidt orthogonalization of the
elements $\{Dp_1(\rho^\vee), ... Dp_r(\rho^\vee) \}$ gives the principal basis
of $\Lie{h}$. Similarly the orthogonalization of the elements $\{Dp_1(\rho),
>... Dp_r(\rho) \}$ produces the principal basis of the Cartan subalgebra of
$\lLie{g}$, the Langlands dual of $\Lie{g}$.


title: On the H\"ormander multiplier theorem and modulation spaces

abstract:
  It is known that the Sobolev space $L^2_s$ with $s>n/2$ appeared in the
H\"ormander multiplier theorem can be replaced by the Besov space
$B^{2,1}_{n/2}$. On the other hand, the Besov space $B_{n/2}^{2,1}$ is
continuously embedded in the modulation space $M^{2,1}_0$. In this paper, we
consider the problem whether we can replace $B_{n/2}^{2,1}$ by $M^{2,1}_0$.


title:
Geometry of Carnot--Carath\'{e}odory Spaces, Differentiability and
  Coarea Formula

abstract:
  We give a simple proof of Gromov's Theorem on nilpotentization of vector
fields, and exhibit a new method for obtaining quantitative estimates of
comparing geometries of two different local Carnot groups in
Carnot--Carath\'{e}odory spaces with $C^{1,\alpha}$-smooth basis vector fields,
$\alpha\in[0,1]$. From here we obtain the similar estimates for comparing
geometries of a Carnot--Carath\'{e}odory space and a local Carnot group. These
two theorems imply basic results of the theory: Gromov type Local Approximation
Theorems, and for $\alpha>0$ Rashevski\v{\i}-Chow Theorem and Ball--Box
Theorem, etc. We apply the obtained results for proving $hc$-differentiability
of mappings of Carnot--Carath\'{e}odory spaces with continuous horizontal
derivatives. The latter is used in proving the coarea formula for some classes
of contact mappings of Carnot--Carath\'{e}odory spaces.


title: Unusual magnetic behavior in ferrite hollow nanospheres

abstract:
  We report unusual magnetic behavior in iron oxide hollow nanospheres of 9.3
$nm$ in diameter. The large fraction of atoms existing at the inner and outer
surfaces gives rise to a high magnetic disorder. The overall magnetic behavior
can be explained considering the coexistence of a soft superparamagnetic phase
and a hard phase corresponding to the highly frustrated cluster-glass like
phase at the surface regions.


title: The Anti-Symmetric GUE Minor Process

abstract:
  Our study is initiated by a multi-component particle system underlying the
tiling of a half hexagon by three species of rhombi. In this particle system
species $j$ consists of $\lfloor j/2 \rfloor$ particles which are interlaced
with neigbouring species. The joint probability density function (PDF) for this
particle system is obtained, and is shown in a suitable scaling limit to
coincide with the joint eigenvalue PDF for the process formed by the successive
minors of anti-symmetric GUE matrices, which in turn we compute from first
principles. The correlations for this process are determinantal and we give an
explicit formula for the corresponding correlation kernel in terms of Hermite
polynomials. Scaling limits of the latter are computed, giving rise to the Airy
kernel, extended Airy kernel and bead kernel at the soft edge and in the bulk,
as well as a new kernel at the hard edge.


title: Grover's algorithm and human memory

abstract:
  In this article we consider an experimental study showing the influence of
emotion regulation strategies on human memory performance: part of such
experimental results are difficult to explain within a classic cognitive
allocation model. We provide a first attempt to build a model of human memory
processes based on a quantum algorithm, the Grover's algorithm, which allows to
search a particular item within an unsorted set of items more efficiently than
any classic search algorithm. Based on Grover's algorithm paradigm, this new
memory model results to have interesting features: it is an iterative process,
it uses parallelism and interference effects. Moreover, the strength of such
interference effects depends on a parameter of the generalized Grover's
algorithm, called the phase, which admits an interpretation in terms of the
emotions involved by the items and by the emotion regulation strategies. Thus
we show that a reasonable choice of the phase is able to describe correctly the
experimental results we consider.


title: V2324Cyg - an F-type star with fast wind

abstract:
  For the first time high-resolution optical spectroscopy of the variable star
V2324Cyg associated with the IR-source IRAS20572+4919 is made. More than 200
absorption features (mostly FeII, TiII, CrII, YII, BaII, and YII) are
identified within the wavelength interval 4549-7880AA. The spectral type and
rotation velocity of the star are found to be F0III and Vsini=69km/s,
respectively. HI and NaID lines have complex PCyg-type profiles with an
emission component. Neither systematic trend of radial velocity Vr with line
depth Ro nor temporal variability of Vr have been found. We determined the
average heliocentric radial velocity Vr=-16.8\pm 0.6km/s. The radial velocities
inferred from the cores of the absorption components of the H$\beta$ and NaI
wind lines vary from -140 to -225km/s (and the expansion velocities of the
corresponding layers, from about 120 to 210km/s). The maximum expansion
velocity is found for the blue component of the split H$\alpha$ absorption:
450km/s for December 12, 1995. The model atmospheres method is used to
determine the star's parameters: Teff=7500K, log g=2.0, $\xi_t$=6.0km/s, and
metallicity, which is equal to the solar value. The main peculiarity of the
chemical abundances pattern is the overabundance of lithium and sodium. The
results cast some doubt on the classification of V2324Cyg as a post-AGB star.


title: Strongly Interacting Gauge Mediation at the LHC

abstract:
  Strongly interacting gauge mediation (SIGM) of supersymmetry breaking is very
attractive, since it naturally predicts a light gravitino of mass $\lsim{\cal
O}(10)$ eV, which causes no cosmological problem. We discuss various signatures
of the SIGM in the early stage (a low integrated luminosity period) of the LHC
experiments. We show, in particular, a possible way to discriminate it from the
conventional gauge mediation by counting the number of high $P_{\rm T}$
leptons.


title: Chaplygin gas in decelerating DGP gravity

abstract:
  Explanations to the accelerated expansion of the Universe are usually sought
either in modifications of Einstein gravity or in new forms of energy density.
An example of modified gravity is the braneworld Dvali-Gabadadze-Porrati (DGP)
model which is characterized by a length scale which marks the cross-over
between physics occurring in our four-dimensional brane and in a
five-dimensional bulk space. An example of dark energy is Chaplygin gas which
has similar asymptotic properties at early and late cosmic times. Since
Chaplygin gas gives too much acceleration we combine it with the
self-decelerating branch of the DGP model, taking the cross-over scales to be
proportional. This 3-parameter model fits supernovae data with a
goodness-of-fit equalling that of the LambdaCDM model. In contrast to
generalized DGP models and Chaplygin gas models, this model is unique in the
sense that it does not reduce to LambdaCDM for any choice of parameters.


title:
Tailoring exchange interactions in engineered nanostructures: Ab initio
  study

abstract:
  We present a novel approach to spin manipulation in atomic-scale
nanostructures. Our ab initio calculations clearly demonstrate that it is
possible to tune magnetic properties of sub-nanometer structures by adjusting
the geometry of the system. By the example of two surface-based systems we
demonstrate that (i) the magnetic moment of a single adatom coupled to a buried
magnetic Co layer can be stabilized in either a ferromagnetic or an
antiferromagnetic configuration depending on the spacer thickness. It is found
that a buried Co layer has a profound effect on the exchange interaction
between two magnetic impurities on the surface. (ii) The exchange interaction
between magnetic adatoms can be manipulated by introducing artificial
nonmagnetic Cu chains to link them.