title:
Quantum charge diffusion in underdamped Josephson junctions and
  superconducting nanowires

abstract:
  The effect of quantum fluctuations on the current-voltage characteristics of
Josephson junctions and superconducting nanowires is studied in the underdamped
limit. Quantum fluctuations induce transitions between a Coulomb--blockade and
a supercurrent branch, and can significantly modify the shape of
current-voltage characteristics in the case of a highly resistive environment.
Owing to the phase-charge duality, our results can be directly extended to the
opposite overdamped limit.


title: Uniqueness of $\bf C^*$- and $\bf C_+$-actions on Gizatullin surfaces

abstract:
  A Gizatullin surface is a normal affine surface $V$ over $\bf C$, which can
be completed by a zigzag; that is, by a linear chain of smooth rational curves.
In this paper we deal with the question of uniqueness of $\bf C^*$-actions and
$\bf A^1$-fibrations on such a surface $V$ up to automorphisms. The latter
fibrations are in one to one correspondence with $\bf C_+$-actions on $V$
considered up to a "speed change".
  Non-Gizatullin surfaces are known to admit at most one $\bf A^1$-fibration
$V\to S$ up to an isomorphism of the base $S$. Moreover an effective $\bf
C^{*}$-action on them, if it does exist, is unique up to conjugation and
inversion $t\mapsto t^{-1}$ of $\bf C^*$. Obviously uniqueness of $\bf
C^*$-actions fails for affine toric surfaces; however we show in this case that
there are at most two conjugacy classes of $\bf A^1$-fibrations. There is a
further interesting family of non-toric Gizatullin surfaces, called the
Danilov-Gizatullin surfaces, where there are in general several conjugacy
classes of $\bf C^*$-actions and $\bf A^1$-fibrations.
  In the present paper we obtain a criterion as to when $\bf A^1$-fibrations of
Gizatullin surfaces are conjugate up to an automorphism of $V$ and the base
$S$. We exhibit as well a large subclasses of Gizatullin $\bf C^{*}$-surfaces
for which a $\bf C^*$-action is essentially unique and for which there are at
most two conjugacy classes of $\bf A^1$-fibrations over $\bf A^1$.


title: Adjoints and Formal Adjoints of Matrices of Unbounded Operators

abstract:
  In this paper we {\em discuss} diverse aspects of mutual relationship between
adjoints and formal adjoints of unbounded operators bearing a matrix structure.
We emphasize on the behaviour of row and column operators as they turn out to
be the germs of an arbitrary matrix operator, providing most of the information
about the latter {as it is the troublemaker}.


title:
Phase rigidity breaking in open Aharonov-Bohm ring coupled to a
  cantilever

abstract:
  The conductance and the transmittance phase shifts of a two-terminal
Aharonov-Bohm (AB) ring are analyzed in the presence of mechanical
displacements due to coupling to an external can- tilever. We show that phase
rigidity is broken, even in the linear response regime, by means of inelastic
scattering due to phonons. Our device provides a way of observing continuous
variation of the transmission phase through a two-terminal
nano-electro-mechanical system (NEMS). We also propose measurements of phase
shifts as a way to determine the strength of the electron-phonon coupling in
NEMS.


title: Hard QCD probes to quark-gluon plasma

abstract:
  Completely unexplored regimes of QCD, dominated by high-density/temperature
effects, are available in heavy ion experiments at collider energies. The
successful RHIC program shows how relevant the high transverse momentum part of
the spectrum is for the characterization of the properties of the created
medium. It points, as well, to interesting properties of the nuclear wave
function at small fraction of momentum x, probably dominated by saturated color
fields. In both domains, the imminent LHC program will provide a phase space
enlarged by orders of magnitude with respect to those studied at RHIC. I will
review the present status of hard probes in heavy ion collisions as well as the
expectations for the LHC.


title: Vicinal silicon surfaces: from step density wave to faceting

abstract:
  This paper investigates faceting mechanisms induced by electromigration in
the regime where atomic steps are transparent. For this purpose we study
several vicinal orientations by means of in-situ (optical diffraction,
electronic microscopy) as well as ex-situ (AFM, microprofilometry)
visualization techniques. The data show that faceting proceeds in two stages.
The first stage is short and leads to the appearance of a step density wave,
with a wavelength roughly independent of the surface orientation. The second
stage is much slower, and leads to the formation of a hill-and-valley
structure, the period of which depends on the initial surface orientation. A
simple continuum model enables us to point out why the wavelength of the step
density wave does not depend on the microscale details of the surface. The
final wavelength is controlled by the competition between elastic step-step
interaction and facet edge energy cost. Finally, the surface stress angular
dependence is shown to emerge as a coarsed-grained picture from the step model.


title:
The role of the slope of `realistic' potential barriers in preventing
  relativistic tunnelling in the Klein zone

abstract:
  The transmission of fermions of mass m and energy E through an electrostatic
potential barrier of rectangular shape (i.e. supporting an infinite electric
field), of height U> E + m - due to the many-body nature of the Dirac equation
evidentiated by the Klein paradox - has been widely studied. We exploit here
the analytical solution, given by Sauter for the linearly rising potential
step, to show that the tunnelling rate through a more realistic trapezoidal
barrier is exponentially depressed, as soon as the length of the regions
supporting a finite electric field exceeds the Compton wavelenght of the
particle - the latter circumstance being hardly escapable in most realistic
cases.


title: A Review of Recent Results from the Tevatron

abstract:
  The D0 and CDF experiments have been taking data at the Run 2 of the Tevatron
Collider since 2001. We present a selection of recent results, most of them
obtained with an integrated luminosity of $\simeq$ 1 fb$^{-1}$. I will describe
the most important facets of the physics programme and detail some results.
Recent direct limits on standard model Higgs obtained at the Tevatron, and
their their prospects will be also reviewed.


title: Gelfand-Shilov spaces, Structural and Kernel theorems

abstract:
  It was shown recently that the space isomorphic with an Gelfand Shilov space
is well adapted for the use in quantum field theory with a fundamental length.
It is our believe that all Gelfand Shilov spaces, especially those with
quasianalytic test function spaces, are good domains for the quantum field
theory. The theory requires technical results from the theory of generalized
functions and not merely differential calculus and well defined Fourier
transform, but also the kernel theorem and the structural theorem. In the paper
we give the structural (regularity) theorem and kernel theorem for
Gelfand-Shilov spaces, of Roumieu and Beurling type.


title: Topological objects in QCD

abstract:
  Topological excitations are prominent candidates for explaining
nonperturbative effects in QCD like confinement. In these lectures, I cover
both formal treatments and applications of topological objects. The typical
phenomena like BPS bounds, topology, the semiclassical approximation and chiral
fermions are introduced by virtue of kinks. Then I proceed in higher dimensions
with magnetic monopoles and instantons and special emphasis on calorons.
Analytical aspects are discussed and an overview over models based on these
objects as well as lattice results is given.


title: Kaon production from 1 to 40 A GeV

abstract:
  Kaon production is studied within the Giessen Boltzmann-Uehling-Uhlenbeck
(GiBUU) model. Results are compared with experiment and with other models. The
influence of the kaon potential on the kaon azimuthal distributions at SIS
energies is considered. We also discuss the role of the many-body collisions at
high-density phase of reaction.


title:
Double quantum dot with integrated charge sensor based on Ge/Si
  heterostructure nanowires

abstract:
  Coupled electron spins in semiconductor double quantum dots hold promise as
the basis for solid-state qubits. To date, most experiments have used III-V
materials, in which coherence is limited by hyperfine interactions. Ge/Si
heterostructure nanowires seem ideally suited to overcome this limitation: the
predominance of spin-zero nuclei suppresses the hyperfine interaction and
chemical synthesis creates a clean and defect-free system with highly
controllable properties. Here we present a top gate-defined double quantum dot
based on Ge/Si heterostructure nanowires with fully tunable coupling between
the dots and to the leads. We also demonstrate a novel approach to charge
sensing in a one-dimensional nanostructure by capacitively coupling the double
dot to a single dot on an adjacent nanowire. The double quantum dot and
integrated charge sensor serve as an essential building block required to form
a solid-state spin qubit free of nuclear spin.


title: Expanders and the Affine Building of ${\rm Sp}_n$

abstract:
  For $n \geq 2$ and a local field $K$, let $\Delta_n$ denote the affine
building naturally associated to the symplectic group ${\rm Sp}_n(K)$. We
compute the spectral radius of the subgraph $Y_n$ of $\Delta_n$ induced by the
special vertices in $\Delta_n$, from which it follows that $Y_n$ is an analogue
of a family of expanders and is non-amenable.


title:
Evolution of Anisotropy of Parton System from Relativistic Heavy-Ion
  Collisions

abstract:
  Evolution of anisotropy in momentum and coordinate space of the parton system
produced in relativistic heavy-ion collisions is discussed within the
free-streaming approximation. The momentum distribution evolves from the
prolate shape - elongated along the beam - to the oblate one - squeezed along
the beam. At the same time the eccentricity in the coordinate space, which
occurs at finite values of impact parameter, decreases. It is argued that the
parton system reaches local thermodynamic equilibrium before the momentum
distribution becomes oblate.


title:
Consistent reasoning about a continuum of hypotheses on the basis of
  finite evidence

abstract:
  In the modern Bayesian view classical probability theory is simply an
extension of conventional logic, i.e., a quantitative tool that allows for
consistent reasoning in the presence of uncertainty. Classical theory
presupposes, however, that--at least in principle--the amount of evidence that
an experimenter can accumulate always matches the size of the hypothesis space.
I investigate how the framework for consistent reasoning must be modified in
non-classical situations where hypotheses form a continuum, yet the maximum
evidence accessible through experiment is not allowed to exceed some finite
upper bound. Invoking basic consistency requirements pertaining to the
preparation and composition of systems, as well as to the continuity of
probabilities, I show that the modified theory must have an internal symmetry
isomorphic to the unitary group. It thus appears that the only consistent
algorithm for plausible reasoning about a continuum of hypotheses on the basis
of finite evidence is furnished by quantum theory in complex Hilbert space.


title: A dust component 2 kpc above the plane in NGC 891

abstract:
  The halo of NGC 891 has been the subject of studies for more than a decade.
One of its most striking features is the large asymmetry in H$\alpha$ emission.
In this letter, we will take a quantitative look at this asymmetry at different
wavelengths for the first time. We suggest that NGC 891 is intrinsically almost
symmetric and the large asymmetry in H$\alpha$ emission is mostly due to dust
attenuation. We will quantify the additional optical depth needed to cause the
observed asymmetry in this model. By comparing large strips on the North East
side of the galaxy with strips covering the same area in the South West we can
quantify and analyze the asymmetry in the different wavelengths. From the 24
$\mu$m emission we find that the intrinsic asymmetry in star formation in NGC
891 is small i.e., $\sim 30%$. The additional asymmetry in H$\alpha$ is modeled
as additional symmetric dust attenuation which extends up to $\sim$ 40\arcsec
(1.9 kpc) above the plane of the galaxy with a mid-plane value of $\tau$=0.8
and a scale height of 0.5 kpc


title: Heavy Flavor Production in DGLAP improved Saturation Model

abstract:
  The saturation model with DGLAP evolution is shown to give good description
of the production of the charm and beauty quarks in deep inelastic scattering.
The modifications of saturation properties caused by the presence of heavy
quarks are also discussed.


title:
Narrow bandwidth interference filter-stabilized diode laser systems for
  the manipulation of neutral atoms

abstract:
  We present and investigate different external cavity diode laser (ECDL)
configurations for the manipulation of neutrals atoms, wavelength-stabilized by
a narrow-band high transmission interference filter. A novel diode laser,
providing high output power of more than 1 W, with a linewidth of less than 200
kHz, based on a self-seeded tapered amplifier chip has been developed.
Additionally, we compare the optical and spectral properties of two laser
systems based on common laser diodes, differing in their coating, as well as
one, based on a distributed-feedback (DFB) diode. The linear cavity setup in
all these systems combines a robust and compact design with a high wavelength
tunability and an improved stability of the optical feedback compared to diode
laser setups using diffraction gratings for wavelength discrimination.


title:
MOST photometry and DDO spectroscopy of the eclipsing (white dwarf + red
  dwarf) binary V471 Tau

abstract:
  The Hyades K2V+WD system 471 Tau is a prototype post-common envelope system
and a likely cataclysmic binary progenitor. We present 10 days of nearly
continuous optical photometry by the MOST (Microvariability & Oscillations of
STars) satellite and partly simultaneous optical spectroscopy from DDO (David
Dunlap Observatory) of the binary. The photometric data indicate that the spot
coverage of the K dwarf component was less than observed in the past,
suggesting that we monitored the star close to a minimum in its activity cycle.
Despite the low spot activity, we still detected seven flare-like events whose
estimated energies are among the highest ever observed in V471 Tau and whose
times of occurrence do not correlate with the binary orbital phase. A detailed
O-C analysis of the times of eclipse over the last ~35 years reveals timing
variations which could be explained in several ways, including perturbations by
an as-yet-undetected third body in the system or by a small orbital
eccentricity inducing slow apsidal motion. The DDO spectra result in improved
determinations of the K dwarf projected rotation velocity, V_K sin i = 92 km
s^-1, and the orbital amplitude, K_K=150.5 km s^-1. The spectra also allow us
to measure changes in H_alpha emission strength and radial velocity (RV)
variations. We measure a larger H_alpha velocity amplitude than found
previously suggesting that the source of the emission in V471 Tau was less
concentrated around the sub-white-dwarf point on the K star than had been
observed in previous studies.


title:
Efficient analysis and design of low-loss whispering-gallery-mode
  coupled resonator optical waveguide bends

abstract:
  Waveguides composed of electromagnetically-coupled optical microcavities
(coupled resonator optical waveguides or CROWs) can be used for light guiding,
slowing and storage. In this paper, we present a two-dimensional analysis of
finite-size straight and curved CROW sections based on a rigorous Muller
boundary integral equations method. We study mechanisms of the coupling of
whispering gallery (WG) modes and guiding light around bends in CROWs composed
of both identical and size-mismatched microdisk resonators. Our accurate
analysis reveals differences in WG modes coupling in the vicinity of bends in
CROWs composed of optically-large and wavelength-scale microcavities. We
propose and discuss possible ways to design low-loss CROW bends and to reduce
bend losses. These include selecting specific bend angles depending on the
azimuthal order of the WG mode and tuning the radius of the microdisk
positioned at the CROW bend.


title:
Longitudinal impedance and wake from XFEL undulators. Impact on
  current-enhanced SASE schemes

abstract:
  In this article we derive longitudinal impedance and wake function for an
undulator setup with arbitrary undulator parameter, taking into account a
finite transverse size of the electron bunch. Earlier studies considered a line
density-distribution of electrons instead. We focus our attention on the
long-wavelength asymptote (compared with resonance wavelength), at large
distance of the electron bunch from the undulator entrance compared to the
overtaking length, and for large vacuum-chamber size compared to the typical
transverse size of the field. These restrictions define a parameter region of
interest for practical applications. We calculate a closed expression for
impedance and wake function that may be evaluated numerically in the most
general case. Such expression allows us to derive an analytical solution for a
Gaussian transverse and longitudinal bunch shape. Finally, we study the
feasibility of current-enhanced SASE schemes (ESASE) recently proposed for
LCLS, that fall well-within our approximations. Numerical estimations presented
in this paper indicate that impedance-induced energy spread is sufficient to
seriously degrade the FEL performance. Our conclusion is in contrast with
results in literature, where wake calculations for the LCLS case are given in
free-space, as if the presence of the undulator were negligible.


title: Some questions of Monte-Carlo modeling on nontrivial bundles

abstract:
  In this work are considered some questions of Monte-Carlo modeling on
nontrivial bundles. As a basic example is used problem of generation of
straight lines in 3D space, related with modeling of interaction of a solid
body with a flux of particles and with some other tasks. Space of lines used in
given model is example of nontrivial fiber bundle, that is equivalent with
tangent sheaf of a sphere.


title: Partition Identities and the Coin Exchange Problem

abstract:
  The number of partitions of n into parts divisible by a or b equals the
number of partitions of n in which each part and each difference of two parts
is expressible as a non-negative integer combination of a or b. This
generalizes identities of MacMahon and Andrews. The analogous identities for
three or more integers (in place of a,b) hold in certain cases.


title: Search for Supernova Neutrino Bursts at Super-Kamiokande

abstract:
  The result of a search for neutrino bursts from supernova explosions using
the Super-Kamiokande detector is reported. Super-Kamiokande is sensitive to
core-collapse supernova explosions via observation of their neutrino emissions.
The expected number of events comprising such a burst is ~10^4 and the average
energy of the neutrinos is in few tens of MeV range in the case of a
core-collapse supernova explosion at the typical distance in our galaxy (10
kiloparsecs); this large signal means that the detection efficiency anywhere
within our galaxy and well past the Magellanic Clouds is 100%. We examined a
data set which was taken from May, 1996 to July, 2001 and from December, 2002
to October, 2005 corresponding to 2589.2 live days. However, there is no
evidence of such a supernova explosion during the data-taking period. The 90%
C.L. upper limit on the rate of core-collapse supernova explosions out to
distances of 100 kiloparsecs is found to be 0.32 SN/year.


title: On advanced fluid modelling of drift wave turbulence

abstract:
  The Dupree-Weinstock renormalization is used to prove that a reactive closure
exists for drift wave turbulence in magnetized plasmas. The result is used to
explain recent results in gyrokinetic simulations and is also related to the
Mattor-Parker closure. The level of closure is found in terms of applied
external sources.


title:
Universal power law behaviors in genomic sequences and evolutionary
  models

abstract:
  We study the length distribution of a particular class of DNA sequences known
as 5'UTR exons. These exons belong to the messanger RNA of protein coding
genes, but they are not coding (they are located upstream of the coding portion
of the mRNA) and are thus less constrained from an evolutionary point of view.
We show that both in mouse and in human these exons show a very clean power law
decay in their length distribution and suggest a simple evolutionary model
which may explain this finding. We conjecture that this power law behaviour
could indeed be a general feature of higher eukaryotes.

categories: q-bio.GN cond-mat.other physics.bio-ph q-bio.QM


title: Spectral Methods for Numerical Relativity

abstract:
  Equations arising in General Relativity are usually too complicated to be
solved analytically and one has to rely on numerical methods to solve sets of
coupled partial differential equations. Among the possible choices, this paper
focuses on a class called spectral methods where, typically, the various
functions are expanded onto sets of orthogonal polynomials or functions. A
theoretical introduction on spectral expansion is first given and a particular
emphasis is put on the fast convergence of the spectral approximation. We
present then different approaches to solve partial differential equations,
first limiting ourselves to the one-dimensional case, with one or several
domains. Generalization to more dimensions is then discussed. In particular,
the case of time evolutions is carefully studied and the stability of such
evolutions investigated. One then turns to results obtained by various groups
in the field of General Relativity by means of spectral methods. First, works
which do not involve explicit time-evolutions are discussed, going from rapidly
rotating strange stars to the computation of binary black holes initial data.
Finally, the evolutions of various systems of astrophysical interest are
presented, from supernovae core collapse to binary black hole mergers.


title:
Simulation of two spin-$s$ singlet correlations for all $s$ involving
  spin measurements

abstract:
  In a recent paper [A. Ahanj et al., quant-ph/0603053], we gave a classical
protocol to simulate quantum correlations corresponding to the spin $s$ singlet
state for the infinite sequence of spins satisfying $2s+1 = 2^{n}$. In the
present paper, we have generalized this result by giving a classical protocol
to exactly simulate quantum correlations implied by the spin-$s$ singlet state
corresponding to all integer as well as half-integer spin values $s$. The class
of measurements we consider here are only those corresponding to spin
observables, as has been done in the above-mentioned paper. The required amount
of communication is found to be $\lceil {\rm log}_{2} (s + 1) \rceil$ in the
worst case scenario, where $\lceil x \rceil$ is the least integer greater than
or equal to $x$.


title:
The fraction of binary systems in the core of thirteen low-density
  Galactic globular clusters

abstract:
  We used deep observations collected with ACS@HST to derive the fraction of
binary systems in a sample of thirteen low-density Galactic globular clusters.
By analysing the color distribution of Main Sequence stars we derived the
minimum fraction of binary systems required to reproduce the observed
color-magnitude diagram morphologies. We found that all the analysed globular
clusters contain a minimum binary fraction larger than 6% within the core
radius. The estimated global fractions of binary systems range from 10% to 50%
depending on the cluster. A dependence of the relative fraction of binary
systems on the cluster age has been detected, suggesting that the binary
disruption process within the cluster core is active and can significantly
reduce the binary content in time.


title: Laser cooling of unbound atoms in nondissipative optical lattices

abstract:
  The semiclassical theory of laser cooling is applied for the analysis of
cooling of unbound atoms with the values of the ground and exited state angular
moments 1/2 in a one-dimensional nondissipative optical lattice. We show that
in the low-saturation limit with respect to the pumping field a qualitative
interpretation of the cooling mechanisms can be made by the consideration of
effective two-level system of the ground-state sublevels. It is clarified that
in the limit of weak Raman transitions the cooling mechanism is similar to the
Doppler mechanism, which is known in the theory of two-level atom. In the limit
of strong Raman transitions the cooling mechanism is similar to the known
Sisyphus mechanism. In the slow atom approximation the analytical expressions
for the coefficients of friction, spontaneous and induced diffusion are given,
and the kinetic temperature is estimated.


title:
Study of the Born-Oppenheimer Approximation for Mass-Scaling of Cold
  Collision Properties

abstract:
  Asymptotic levels of the A $^1\Sigma_u^+$ state of the two isotopomers
$^{39}{\rm K}_2$ and $^{39}{\rm K}^{41}{\rm K}$ up to the dissociation limit
are investigated with a Doppler-free high resolution laser-spectroscopic
experiment in a molecular beam. The observed level structure can be reproduced
correctly only if a mass dependent correction term is introduced for the
interaction potential. The applied relative correction in the depth of the
potential is $10^{-6}$, which is in the order of magnitude expected for
corrections of the Born-Oppenheimer approximation. A similar change in ground
state potentials might lead to significant changes of mass-scaled properties
describing cold collisions like the s-wave scattering length.


title:
Existence theorem and blow-up criterion of the strong solutions to the
  Magneto-micropolar fluid equations

abstract:
  In this paper we study the magneto-micropolar fluid equations in $\R^3$,
prove the existence of the strong solution with initial data in $H^s(\R^3)$ for
$s> {3/2}$, and set up its blow-up criterion. The tool we mainly use is
Littlewood-Paley decomposition, by which we obtain a Beale-Kato-Majda type
blow-up criterion for smooth solution $(u,\omega,b)$ which relies on the
vorticity of velocity $\nabla\times u$ only.


title:
First observations of beam losses due to bound-free pair production in a
  heavy-ion collider

abstract:
  We report the first observations of beam losses due to bound-free pair
production at the interaction point of a heavy-ion collider. This process is
expected to be a major luminosity limit for the Large Hadron Collider (LHC)
when it operates with 208Pb82+ ions because the localized energy deposition by
the lost ions may quench superconducting magnet coils. Measurements were
performed at the Relativistic Heavy Ion Collider (RHIC) during operation with
100 GeV/nucleon 63Cu29+ ions. At RHIC, the rate, energy and magnetic field are
low enough so that magnet quenching is not an issue. The hadronic showers
produced when the single-electron ions struck the RHIC beampipe were observed
using an array of photodiodes. The measurement confirms the order of magnitude
of the theoretical cross section previously calculated by others.


title: Resource control of object-oriented programs

abstract:
  A sup-interpretation is a tool which provides an upper bound on the size of a
value computed by some symbol of a program. Sup-interpretations have shown
their interest to deal with the complexity of first order functional programs.
For instance, they allow to characterize all the functions bitwise computable
in Alogtime. This paper is an attempt to adapt the framework of
sup-interpretations to a fragment of oriented-object programs, including
distinct encodings of numbers through the use of constructor symbols, loop and
while constructs and non recursive methods with side effects. We give a
criterion, called brotherly criterion, which ensures that each brotherly
program computes objects whose size is polynomially bounded by the inputs
sizes.


title: On the origin of thermal string gas

abstract:
  We investigate decaying D-branes as the origin of the thermal string gas of
string gas cosmology. We consider initial configurations of low-dimensional
branes and argue that they can time evolve to thermal string gas. We find that
there is a range in the weak string coupling and fast brane decay time regimes,
where the initial configuration could drive the evolution of the dilaton to
values, where exactly three spacelike directions grow large.


title:
Exact treatment of linear difference equations with noncommutative
  coefficients

abstract:
  The exact solution of a Cauchy problem related to a linear second-order
difference equation with constant noncommutative coefficients is reported.


title: Signatures of fractal clustering of aerosols advected under gravity

abstract:
  Aerosols under chaotic advection often approach a strange attractor. They
move chaotically on this fractal set but, in the presence of gravity, they have
a net vertical motion downwards. In practical situations, observational data
may be available only at a given level, for example at the ground level. We
uncover two fractal signatures of chaotic advection of aerosols under the
action of gravity. Each one enables the computation of the fractal dimension
$D_{0}$ of the strange attractor governing the advection dynamics from data
obtained solely at a given level. We illustrate our theoretical findings with a
numerical experiment and discuss their possible relevance to meteorology.


title:
The Minimal Number of Periodic Orbits of Periods Guaranteed in
  Sharkovskii's Theorem

abstract:
  Let f(x) be a continuous function from a compact real interval into itself
with a periodic orbit of minimal period m, where m is not an integral power of
2. Then, by Sharkovsky's theorem, for every positive integer n with m \prec n
in the Sharkovsky's ordering defined below, a lower bound on the number of
periodic orbits of f(x) with minimal period n is 1. Could we improve this lower
bound from 1 to some larger number? In this paper, we give a complete answer to
this question.


title: Local coherence and deflation of the low quark modes in lattice QCD

abstract:
  The spontaneous breaking of chiral symmetry in QCD is known to be linked to a
non-zero density of eigenvalues of the massless Dirac operator near the origin.
Numerical studies of two-flavour QCD now suggest that the low quark modes are
locally coherent to a certain extent. As a consequence, the modes can be
simultaneously deflated, using local projectors, with a total computational
effort proportional to the lattice volume (rather than its square). Deflation
has potentially many uses in lattice QCD. The technique is here worked out for
the case of quark propagator calculations, where large speed-up factors and a
flat scaling behaviour with respect to the quark mass are achieved.


title: Diffuse HI Disks in Isolated Galaxies

abstract:
  In order to investigate the contribution of diffuse components to their total
HI emission, we have obtained high precision HI line flux densities with the
100m Green Bank Telescope for a sample of 100 isolated spiral and irregular
galaxies which we have previously observed with the 43m telescope. A comparison
of the observed HI line fluxes obtained with the two different telescopes,
characterized by half-power beam widths of 9 arcmin and 21 arcmin respectively,
exploits a ``beam matching'' technique to yield a statistical determination of
the occurrence of diffuse HI components in their disks. A simple model of the
HI distribution within a galaxy well describes ~75 % of the sample and accounts
for all of the HI line flux density. The remaining galaxies are approximately
evenly divided into two categories: ones which appear to possess a
significantly more extensive HI distribution than the model predicts, and ones
for which the HI distribution is more centrally concentrated than predicted.
Examples of both extremes can be found in the literature but little attention
has been paid to the centrally concentrated HI systems. Our sample has
demonstrated that galaxies do not commonly possess extended regions of low
surface brightness HI gas which is not accounted for by our current
understanding of the structure of HI disks. Eight HI-rich companions to the
target objects are identified, and a set of extragalactic HI line flux density
calibrators is presented.


title: The few-body problem in terms of correlated gaussians

abstract:
  In their textbook, Suzuki and Varga [Y. Suzuki and K. Varga, {\em Stochastic
Variational Approach to Quantum-Mechanical Few-Body Problems} (Springer,
Berlin, 1998)] present the stochastic variational method in a very exhaustive
way. In this framework, the so-called correlated gaussian bases are often
employed. General formulae for the matrix elements of various operators can be
found in the textbook. However the Fourier transform of correlated gaussians
and their application to the management of a relativistic kinetic energy
operator are missing and cannot be found in the literature. In this paper we
present these interesting formulae. We give also a derivation for new
formulations concerning central potentials; the corresponding formulae are more
efficient numerically than those presented in the textbook.


title: X-ray detection of the substellar twin 2MASS J11011926-7732383 AB

abstract:
  2MASS J11011926-7732383 AB (hereafter 2M1101AB), located in the Cha I star
forming region, is a rare wide-separation brown dwarf binary. XMM-Newton and
Chandra observations of 2M1101AB have allowed us to examine the influence of
physical parameters (mass, bolometric luminosity and effective temperature) on
X-ray emission from a coeval pair of substellar objects. The spatial resolution
of XMM-Newton is not sufficient to separate contributions from the two
components in the binary. The X-ray source detected with XMM-Newton has a
column density compatible with the infrared extinction of component A. On the
other hand, the binary is resolved with Chandra, and the bulk of the X-ray
emission is clearly associated with the photospherically cooler component B.
These apparently contradictory results point at strong variability of 2M1101's
X-ray emission. Combined with previous sensitive X-ray observations from
low-mass members of ChaI, we find a decline of X-ray luminosity with decreasing
(sub)stellar mass that is typical for star forming regions. 2M1101B is the
coolest (spectral type M8.25) and least massive brown dwarf of ChaI detected in
X-rays so far. It is also among the youngest (~1 Myr) substellar ChaI members,
and therefore relatively luminous. Most bona fide brown dwarfs of Cha I have
remained below the sensitivity limits of available X-ray observations, because
of their low luminosity associated with higher age.


title: Measuring the surface stress polar dependence

abstract:
  While measurements of the polar dependence of the surface free energy are
easily available, measurements of the whole polar dependence of the surface
stress of a crystal do not exist. In this paper is presented a new procedure
that allows, for the first time, the experimental determination of the surface
stress polar dependence of a crystal. For this purpose (1) electromigration is
used to control the kinetic faceting of surface orientations that belong to the
equilibrium shape of the crystal and (2) for each destabilised surface, the
period of faceting as well as the crystallographic angles of the appearing
facets are measured by AFM. The so-obtained data lead to a set of equations
whose mathematical solution, compatible with physical constraints, gives access
to the surface stress polar dependence of the whole crystal and thus to a
better understanding of surface stress properties.


title: Riccati equation-based generalization of Dawson's integral function

abstract:
  A new generalization of Dawson's integral function based on the link between
a Riccati nonlinear differential equation and a second-order ordinary
differential equation is reported. The MacLaurin expansion of this generalized
function is built up and to this end an explicit formula for a generic cofactor
of a triangular matrix is deduced.


title: Charged Condensation

abstract:
  We consider Bose-Einstein condensation of massive electrically charged
scalars in a uniform background of charged fermions. We focus on the case when
the scalar condensate screens the background charge, while the net charge of
the system resides on its boundary surface. A distinctive signature of this
substance is that the photon acquires a Lorentz-violating mass in the bulk of
the condensate. Due to this mass, the transverse and longitudinal gauge modes
propagate with different group velocities. We give qualitative arguments that
at high enough densities and low temperatures a charged system of electrons and
helium-4 nuclei, if held together by laboratory devices or by force of gravity,
can form such a substance. We briefly discuss possible manifestations of the
charged condensate in compact astrophysical objects.


title: Absolute surface energy determination

abstract:
  Experimental determination of absolute surface energies remains a challenge.
We propose a simple method based on two independent measurements on 3D and 2D
equilibrium shapes completed by the analysis of the thermal fluctuation of an
isolated step. Using then basic equations (Wulff' theorem, Gibbs-Thomson
equation, thermodynamics fluctuation of an isolated step) allows us to extract
the absolute surface free energy of a singular face. The so-proposed method can
be applied when (i) all orientations exists on the equilibrium shape, (ii) the
surface stress is isotropic. This procedure is applied to the case of Si(111)
where we find a value between 0.59 Jm-2 and 0.83 Jm-2 at 1373 K.


title: Thermoelectric effects in superconducting proximity structures

abstract:
  Attaching a superconductor in good contact with a normal metal makes rise to
a proximity effect where the superconducting correlations leak into the normal
metal. An additional contact close to the first one makes it possible to carry
a supercurrent through the metal. Forcing this supercurrent flow along with an
additional quasiparticle current from one or many normal-metal reservoirs makes
rise to many interesting effects. The supercurrent can be used to tune the
local energy distribution function of the electrons. This mechanism also leads
to finite thermoelectric effects even in the presence of electron-hole
symmetry. Here we review these effects and discuss to which extent the existing
observations of thermoelectric effects in metallic samples can be explained
through the use of the dirty-limit quasiclassical theory.


title:
The periodic table of $n$-categories for low dimensions II: degenerate
  tricategories

abstract:
  We continue the project begun in ``The periodic table of $n$-categories for
low dimensions I'' by examining degenerate tricategories and comparing them
with the structures predicted by the Periodic table. For triply degenerate
tricategories we exhibit a triequivalence with the partially discrete
tricategory of commutative monoids. For the doubly degenerate case we explain
how to construct a braided monoidal category from a given doubly degenerate
category, but show that this does not induce a straightforward comparison
between \bfseries{BrMonCat} and \bfseries{Tricat}. We show how to alter the
natural structure of \bfseries{Tricat} in two different ways to provide a
comparison, but show that only the more brutal alteration yields an
equivalence. Finally we study degenerate tricategories in order to give the
first fully algebraic definition of monoidal bicategories and the full
tricategory structure \bfseries{MonBicat}.


title:
Spirals on Si(111) at sublimation and growth: REM and LODREM
  observations

abstract:
  Using recently proposed improvements of Reflection Electron Microsopy (REM)
we study in perfectly controlled thermodynamics conditions spiral shapes and
spirals on Si(111) surface. It is shown that the new method named low
distortion reflection electron microscopy (LODREM) is a powerful instrument,
resolving in much more details (compared with REM) growth or evaporation
spirals at the crystal surface. More precisely, we examine the distance between
two successive steps of a spiral at growth (or evaporation) with respect to the
supersaturation (or undersaturation). It is found that this distance scales
with an exponent close to -1/2. This result, which deviates from the BCF theory
originates from a non local behavior with a slow kinetic of attachment of the
adatoms at the steps.


title: Formation and Persistence of Spatiotemporal Turing Patterns

abstract:
  This article is concerned with the stability and long-time dynamics of
structures arising from a structureless state. The paradigm is suggested by
developmental biology, where morphogenesis is thought to result from a
competition between chemical reactions and spatial diffusion. A system of two
reaction-diffusion equations for the concentrations of two morphogens is
reduced to a finite system of ordinary differential equations. The stability of
bifurcated solutions of this system is analyzed, and the long-time asymptotic
behavior of the bifurcated solutions is established rigorously. The
Schnakenberg and Gierer-Meinhardt equations are discussed as examples.


title:
Space-time coding techniques with bit-interleaved coded modulations for
  MIMO block-fading channels

abstract:
  The space-time bit-interleaved coded modulation (ST-BICM) is an efficient
technique to obtain high diversity and coding gain on a block-fading MIMO
channel. Its maximum-likelihood (ML) performance is computed under ideal
interleaving conditions, which enables a global optimization taking into
account channel coding. Thanks to a diversity upperbound derived from the
Singleton bound, an appropriate choice of the time dimension of the space-time
coding is possible, which maximizes diversity while minimizing complexity.
Based on the analysis, an optimized interleaver and a set of linear precoders,
called dispersive nucleo algebraic (DNA) precoders are proposed. The proposed
precoders have good performance with respect to the state of the art and exist
for any number of transmit antennas and any time dimension. With turbo codes,
they exhibit a frame error rate which does not increase with frame length.


title:
Stable crystalline lattices in two-dimensional binary mixtures of
  dipolar particles

abstract:
  The phase diagram of binary mixtures of particles interacting via a pair
potential of parallel dipoles is computed at zero temperature as a function of
composition and the ratio of their magnetic susceptibilities. Using lattice
sums, a rich variety of different stable crystalline structures is identified
including $A_mB_n$ structures. [$A$ $(B)$ particles correspond to large (small)
dipolar moments.] Their elementary cells consist of triangular, square,
rectangular or rhombic lattices of the $A$ particles with a basis comprising
various structures of $A$ and $B$ particles. For small (dipolar) asymmetry
there are intermediate $AB_2$ and $A_2B$ crystals besides the pure $A$ and $B$
triangular crystals. These structures are detectable in experiments on granular
and colloidal matter.


title:
Carrier-carrier entanglement and transport resonances in semiconductor
  quantum dots

abstract:
  We study theoretically the entanglement created in a scattering between an
electron, incoming from a source lead, and another electron bound in the ground
state of a quantum dot, connected to two leads. We analyze the role played by
the different kinds of resonances in the transmission spectra and by the number
of scattering channels, into the amount of quantum correlations between the two
identical carriers. It is shown that the entanglement between their energy
states is not sensitive to the presence of Breit-Wigner resonances, while it
presents a peculiar behavior in correspondence of Fano peaks: two close maxima
separated by a minimum, for a two-channel scattering, a single maximum for a
multi-channel scattering. Such a behavior is ascribed to the different
mechanisms characterizing the two types of resonances. Our results suggest that
the production and detection of entanglement in quantum dot structures may be
controlled by the manipulation of Fano resonances through external fields.


title: Cohomology of diffeological spaces and foliations

abstract:
  Let (M,F) be a foliated manifold. We study the relationship between the basic
cohomology Hb(M,F) of the foliation and the De Rham cohomology H(DF) of the
space of leaves M/F as a quotient diffeological space. We prove that for an
arbitrary foliation there is a morphism from H(DF) to Hb(M,F). It is an
isomorphism when F is a Q-foliation.


title:
Hypersurfaces in H^{n+1} and conformally invariant equations: the
  generalized Christoffel and Nirenberg problems

abstract:
  Our first objective in this paper is to give a natural formulation of the
Christoffel problem for hypersurfaces in $H^{n+1}$, by means of the hyperbolic
Gauss map and the notion of hyperbolic curvature radii for hypersurfaces. Our
second objective is to provide an explicit equivalence of this Christoffel
problem with the famous problem of prescribing scalar curvature on $\S^n$ for
conformal metrics, posed by Nirenberg and Kazdan-Warner. This construction lets
us translate into the hyperbolic setting the known results for the scalar
curvature problem, and also provides a hypersurface theory interpretation of
such an intrinsic problem from conformal geometry. Our third objective is to
place the above result into a more general framework. Specifically, we will
show how the problem of prescribing the hyperbolic Gauss map and a given
function of the hyperbolic curvature radii in $H^{n+1}$ is strongly related to
some important problems on conformally invariant PDEs in terms of the Schouten
tensor. This provides a bridge between the theory of conformal metrics on
$\S^n$ and the theory of hypersurfaces with prescribed hyperbolic Gauss map in
$\H^{n+1}$. The fourth objective is to use the above correspondence to prove
that for a wide family of Weingarten functionals $W(\k_1,..., \k_n)$, the only
compact immersed hypersurfaces in $H^{n+1}$ on which $W$ is constant are round
spheres.


title:
Spin Polarized Transport Through a Single-Molecule Magnet:
  Current-Induced Magnetic Switching

abstract:
  Magnetic switching of a single-molecule magnet (SMM) due to spin-polarized
current is investigated theoretically. The charge transfer between the
electrodes takes place via the lowest unoccupied molecular orbital (LUMO) of
the SMM. Generally, the double occupancy of the LUMO level, and a finite
on-site Coulomb repulsion, is taken into account. Owing to the exchange
interaction between electrons in the LUMO level and the SMM's spin, the latter
can be reversed. The perturbation approach (Fermi golden rule) is applied to
calculate current-voltage characteristics. The influence of Coulomb
interactions on the switching process is also analyzed.


title: Stable Border Bases for Ideals of Points

abstract:
  Let $X$ be a set of points whose coordinates are known with limited accuracy;
our aim is to give a characterization of the vanishing ideal $I(X)$ independent
of the data uncertainty. We present a method to compute a polynomial basis $B$
of $I(X)$ which exhibits structural stability, that is, if $\widetilde X$ is
any set of points differing only slightly from $X$, there exists a polynomial
set $\widetilde B$ structurally similar to $B$, which is a basis of the
perturbed ideal $ I(\widetilde X)$.


title:
Study of Di-Pion Transitions Among Upsilon(3S), Upsilon(2S), and
  Upsilon(1S) States

abstract:
  We present measurements of decay matrix elements for hadronic transitions of
the form Upsilon(nS) -> pi pi Upsilon(mS) where (n, m) = (3, 1), (2, 1), and
(3, 2). We reconstruct charged and neutral pion modes with the final state
Upsilon decaying to either mu+mu- or e+e-. Dalitz plot distributions for the
twelve decay modes are fit individually as well as jointly assuming isospin
symmetry, thereby measuring the matrix elements of the decay amplitude. We
observe and account for the anomaly previously noted in the di-pion invariant
mass distribution for the Upsilon(3S) -> pi pi Upsilon(1S) transition and
obtain good descriptions of the dynamics of the decay using the most general
decay amplitude allowed by partial conservation of the axial-vector current
(PCAC) considerations. The fits further indicate that the Upsilon(2S) -> pi pi
Upsilon(1S) and Upsilon(3S) -> pi pi Upsilon(2S) transitions also show the
presence of terms in the decay amplitude that were previously ignored, although
at a relatively suppressed level.


title:
The Geometry of Regular Shear-Free Null Geodesic Congruences, CR
  functions and their Application to the Flat-Space Maxwell Equations

abstract:
  We describe here what appears to be a new structure that is hidden in all
asymptotically vanishing Maxwell fields possessing a non-vanishing total
charge. Though we are dealing with real Maxwell fields on real Minkowski space
nevertheless, directly from the asymptotic field one can extract a complex
analytic world-line defined in complex Minkowski space that gives a unified
Lorentz invariant meaning to both the electric and magnetic dipole moments. In
some sense the world-line defines a `complex center of charge' around which
both electric and magnetic dipole moments vanish.
  The question of how and where does this complex world-line arise is one of
the two main subjects of this work. The other subject concerns what is known in
the mathematical literature as a CR structure. In GR, CR structures naturally
appear in the physical context of shear-free (or asymptotically shear-free)
null geodesic congruences in space-time. For us, the CR structure is associated
with the embedding of Penrose's real three-dimensional null infinity, I^+, as a
surface in a two complex dimensional space, C^2. It is this embedding, via a
complex function, (a CR function), that is our other area of interest.
Specifically we are interested in the `decomposition' of the CR function into
its real and imaginary parts and the physical information contained in this
decomposition.


title: Analysing the elasticity difference tensor of general relativity

abstract:
  The elasticity difference tensor, used in [1] to describe elasticity
properties of a continuous medium filling a space-time, is here analysed from
the point of view of the space-time connection. Principal directions associated
with this tensor are compared with eigendirections of the material metric.
Examples concerning spherically symmetric and axially symmetric space-times are
then presented.


title:
On large automorphism groups of algebraic curves in positive
  characteristic

abstract:
  In his investigation on large $K$-automorphism groups of an algebraic curve,
Stichtenoth obtained an upper bound on the order of the first ramification
group of an algebraic curve $\cX$ defined over an algebraically closed field of
characteristic $p$. Stichtenoth's bound has raised the problem of classifying
all $\K$-automorphism groups $G$ of $\cX$ with the following property: There is
a point $P\in \cX$ for which \begin{equation} |G_P^{(1)}|>\frac{p}{p-1}g.
\end{equation} Such a classification is obtained here by proving Theorem 1.3


title: Lower bounds for moments of zeta prime rho

abstract:
  Assuming the Riemann Hypothesis, we establish lower bounds for moments of the
derivative of the Riemann zeta-function averaged over the non-trivial zeros of
$\zeta(s)$. Our proof is based upon a recent method of Rudnick and
Soundararajan that provides analogous bounds for moments of $L$-functions at
the central point, averaged over families.


title:
Materials with a desired refraction coefficient can be made by embedding
  small particles

abstract:
  A method is proposed to create materials with a desired refraction
coefficient, possibly negative one. The method consists of embedding into a
given material small particles. Given $n_0(x)$, the refraction coefficient of
the original material in a bounded domain $D \subset \R^3$, and a desired
refraction coefficient $n(x)$, one calculates the number $N(x)$ of small
particles, to be embedded in $D$ around a point $x \in D$ per unit volume of
$D$, in order that the resulting new material has refraction coefficient
$n(x)$.


title:
A sample of mJy radio sources at 1.4 GHz in the Lynx and Hercules fields
  - I. Radio imaging, multicolour photometry and spectroscopy

abstract:
  With the goal of identifying high redshift radio galaxies with FRI
classification, here are presented high resolution, wide-field radio
observations, near infra-red and optical imaging and multi-object spectroscopy
of two fields of the Leiden-Berkeley Deep Survey. These fields, Hercules.1 and
Lynx.2, contain a complete sample of 81 radio sources with S(1.4 GHz) > 0.5 mJy
within 0.6 square degrees. This sample will form the basis for a study of the
population and cosmic evolution of high redshift, low power, FRI radio sources
which will be presented in Paper II. Currently, the host galaxy identification
fraction is 86% with 11 sources remaining unidentified at a level of r > 25.2
mag (Hercules; 4 sources) or r > 24.4 mag (Lynx; 7 sources) or K > 20 mag.
Spectroscopic redshifts have been determined for 49% of the sample and
photometric redshift estimates are presented for the remainder of the sample.


title: Special isogenies and tensor product multiplicities

abstract:
  We show that any bijection between two root systems that preserves angles
(but not necessarily lengths) gives rise to inequalities relating tensor
product multiplicities for the corresponding complex semisimple Lie groups (or
Lie algebras). We explain the inequalities in two ways: combinatorially, using
Littelmann's Path Model, and geometrically, using isogenies between algebaric
groups defined over an algebraically closed field of positive characteristic.


title:
The Monitor project: JW 380 -- a 0.26, 0.15 Msol pre main sequence
  eclipsing binary in the Orion Nebula Cluster

abstract:
  We report the discovery of a low-mass (0.26 +/- 0.02, 0.15 +/- 0.01 Msol)
pre-main-sequence eclipsing binary with a 5.3 day orbital period. JW 380 was
detected as part of a high-cadence time-resolved photometric survey (the
Monitor project) using the 2.5m Isaac Newton Telescope and Wide Field Camera
for a survey of a single field in the Orion Nebula Cluster (ONC) region in V
and i bands. The star is assigned a 99 per cent membership probability from
proper motion measurements, and radial velocity observations indicate a
systemic velocity within 1 sigma of that of the ONC. Modelling of the combined
light and radial velocity curves of the system gave stellar radii of 1.19 +0.04
-0.18 Rsol and 0.90 +0.17 -0.03 Rsol for the primary and secondary, with a
significant third light contribution which is also visible as a third peak in
the cross-correlation functions used to derive radial velocities. The masses
and radii appear to be consistent with stellar models for 2-3 Myr age from
several authors, within the present observational errors. These observations
probe an important region of mass-radius parameter space, where there are
currently only a handful of known pre-main-sequence eclipsing binary systems
with precise measurements available in the literature.


title:
The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant
  Luminous Red Galaxy

abstract:
  We report the discovery of an almost complete Einstein ring of diameter 10"
in Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5). Spectroscopic data
from the 6m telescope of the Special Astrophysical Observatory reveals that the
deflecting galaxy has a line-of-sight velocity dispersion in excess of 400 km/s
and a redshift of 0.444, whilst the source is a star-forming galaxy with a
redshift of 2.379. From its color and luminosity, we conclude that the lens is
an exceptionally massive Luminous Red Galaxy (LRG) with a mass within the
Einstein radius of 5 x 10^12 solar masses. This remarkable system provides a
laboratory for probing the dark matter distribution in LRGs at distances out to
3 effective radii, and studying the properties of high redshift star-forming
galaxies.


title: A Robust Atom-Photon Entanglement Source for Quantum Repeaters

abstract:
  We demonstrate a novel way to efficiently and very robust create an
entanglement between an atomic and a photonic qubit. A single laser beam is
used to excite one atomic ensemble and two different spatial modes of scattered
Raman fields are collected to generate the atom-photon entanglement. With the
help of build-in quantum memory, the entanglement still exists after 20.5
$\mu$s storage time which is further proved by the violation of CHSH type
Bell's inequality. Our entanglement procedure is the building block for a novel
robust quantum repeater architecture [Zhao et al, Phys. Rev. Lett. 98, 240502
(2007)]. Our approach can be easily extended to generate high dimensional
atom-photon entanglements.


title: Unique mechanisms from finite two-state trajectories

abstract:
  Single molecule data made of on and off events are ubiquitous. Famous
examples include enzyme turnover, probed via fluorescence, and opening and
closing of ion-channel, probed via the flux of ions. The data reflects the
dynamics in the underlying multi-substate on-off kinetic scheme (KS) of the
process, but the determination of the underlying KS is difficult, and sometimes
even impossible, due to the loss of information in the mapping of the
mutli-dimensional KS onto two dimensions. A way to deal with this problem
considers canonical (unique) forms. (Unique canonical form is constructed from
an infinitely long trajectory, but many KSs.) Here we introduce canonical forms
of reduced dimensions that can handle any KS (i.e. also KSs with symmetry and
irreversible transitions). We give the mapping of KSs into reduced dimensions
forms, which is based on topology of KSs, and the tools for extracting the
reduced dimensions form from finite data. The canonical forms of reduced
dimensions constitute a powerful tool in discriminating between KSs.


title: Numerical Kaehler-Ricci soliton on the second del Pezzo

abstract:
  The second del Pezzo surface is known by work of Tian-Zhu and Wang-Zhu to
admit a unique Kaehler-Ricci soliton. Applying a method described in
hep-th/0703057, we use Ricci flow to numerically compute that soliton metric.
We numerically compute the value of its Perelman entropy (or Gaussian density).


title: Three body resonances in two meson-one baryon systems

abstract:
  We report four $\Sigma$'s and three $\Lambda$'s, in the 1500 - 1800 MeV
region, as two meson - one baryon S-wave $(1/2)^+$ resonances. We solve Faddeev
equations in the coupled channel approach. The invariant mass of one of the
meson-baryon pairs and that of the three particles have been varied and peaks
in the squared three body $T$-matrix have been found very close to the existing
$S$ = -1, $J^P= 1/2^+$ low lying baryon resonances. The input two-body
$t$-matrices for meson-meson and meson-baryon interaction have been calculated
by solving the Bethe-Salpeter equation with the potentials obtained in the
chiral unitary approach.


title:
Pricing American Options for Jump Diffusions by Iterating Optimal
  Stopping Problems for Diffusions

abstract:
  We approximate the price of the American put for jump diffusions by a
sequence of functions, which are computed iteratively. This sequence converges
to the price function uniformly and exponentially fast. Each element of the
approximating sequence solves an optimal stopping problem for geometric
Brownian motion, and can be numerically computed using the classical finite
difference methods. We prove the convergence of this numerical scheme and
present examples to illustrate its performance.


title: Predictions from non trivial Quark-Lepton complementarity

abstract:
  The complementarity between the quark and lepton mixing matrices is shown to
provide robust predictions. We obtain these predictions by first showing that
the matrix V_M, product of the quark (CKM) and lepton (PMNS) mixing matrices,
may have a zero (1,3) entry which is favored by experimental data.
  We obtain that any theoretical model with a vanishing (1,3) entry of V_M that
is in agreement with quark data, solar, and atmospheric mixing angle leads to
$\theta_{13}^{PMNS}=(9{^{+1}_{-2}})^\circ$. This value is consistent with the
present 90% CL experimental upper limit. We also investigate the prediction on
the lepton phases. We show that the actual evidence, under the only assumption
that the correlation matrix V_M product of CKM and PMNS has a zero in the entry
(1,3), gives us a prediction for the three CP-violating invariants J, S_1, and
S_2. A better determination of the lepton mixing angles will give stronger
prediction for the CP-violating invariants in the lepton sector. These will be
tested in the next generation experiments. Finally we compute the effect of non
diagonal neutrino mass in "l_i -> l_j gamma" in SUSY theories with non trivial
Quark-Lepton complementarity and a flavor symmetry. The Quark-Lepton
complementarity and the flavor symmetry strongly constrain the theory and we
obtain a clear prediction for the contribution to "mu -> e gamma" and the "tau"
decays "tau -> e gamma" and "tau -> mu gamma". If the Dirac neutrino Yukawa
couplings are degenerate but the low energy neutrino masses are not degenerate,
then the lepton decays are related among them by the V_M entries. On the other
hand, if the Dirac neutrino Yukawa couplings are hierarchical or the low energy
neutrino masses are degenerate, then the prediction for the lepton decays comes
from the CKM hierarchy.


title: Loschmidt echo and stochastic-like quantum dynamics of nano-particles

abstract:
  We investigate time evolution of prepared vibrational state (system) coupled
to a reservoir with dense spectrum of its vibrational states. We assume that
the reservoir has an equidistant spectrum, and the system - reservoir coupling
matrix elements are independent of the reservoir states. The analytical
solution manifests three regimes of the evolution for the system: (I) weakly
damped oscillations; (II) multicomponent Loschmidt echo in recurrence cycles;
(III) overlapping recurrence cycles. We find the characteristic critical values
of the system - reservoir coupling constant for the transitions between these
regimes. Stochastic dynamics occurs in the regime (III) due to inevoidably in
any real system coarse graining of time or energy measurements, or initial
condition uncertainty. Even though a specific toy model is investigated here,
when properly interpreted it yields quite reasonable description for a variety
of physically relevant phenomena.


title: MadGraph/MadEvent v4: The New Web Generation

abstract:
  We present the latest developments of the MadGraph/MadEvent Monte Carlo event
generator and several applications to hadron collider physics. In the current
version events at the parton, hadron and detector level can be generated
directly from a web interface, for arbitrary processes in the Standard Model
and in several physics scenarios beyond it (HEFT, MSSM, 2HDM). The most
important additions are: a new framework for implementing user-defined new
physics models; a standalone running mode for creating and testing matrix
elements; generation of events corresponding to different processes, such as
signal(s) and backgrounds, in the same run; two platforms for data analysis,
where events are accessible at the parton, hadron and detector level; and the
generation of inclusive multi-jet samples by combining parton-level events with
parton showers. To illustrate the new capabilities of the package some
applications to hadron collider physics are presented:
  1) Higgs search in pp \to H \to W^+W^-: signal and backgrounds.
  2) Higgs CP properties: pp \to H jj$in the HEFT.
  3) Spin of a new resonance from lepton angular distributions.
  4) Single-top and Higgs associated production in a generic 2HDM.
  5) Comparison of strong SUSY pair production at the SPS points.
  6) Inclusive W+jets matched samples: comparison with the Tevatron data.


title: Lateral Effects in Fermion Antibunching

abstract:
  Lateral effects are analyzed in the antibunching of a beam of free
non-interacting fermions. The emission of particles from a source is
dynamically described in a 3D full quantum field-theoretical framework. The
size of the source and the detectors, as well as the temperature of the source
are taken into account and the behavior of the visibility is scrutinized as a
function of these parameters.


title:
Testing AdS/CFT Deviations from pQCD Heavy Quark Energy Loss with Pb+Pb
  at LHC

abstract:
  Heavy quark jet quenching in nuclear collisions at LHC is predicted and
compared using the classical gravity AdS/CFT correspondence and Standard Model
perturbative QCD. The momentum independence and inverse quark mass dependence
of the drag coefficient in AdS/CFT differs substantially from the
characteristic log(pT/M)/pT variation of the drag in QCD. We propose that the
measurement of the momentum dependence of the double ratio of the nuclear
modification factors of charm and bottom jets is a robust observable that can
be used to search for strong coupling deviations from perturbative QCD
predictions.


title:
The extended structure of the remote cluster B514 in M31. Detection of
  extra-tidal stars

abstract:
  We present a study of the density profile of the remote M31 globular cluster
B514, obtained from HST/ACS observations. Coupling the analysis of the
distribution of the integrated light with star counts we can reliably follow
the profile of the cluster out to r~35", corresponding to ~130pc. The profile
is well fitted, out to ~15 core radii, by a King Model having C=1.65. With an
estimated core radius r_c=0.38", this corresponds to a tidal radius of r_t~17"
(~65pc). We find that both the light and the star counts profiles show a
departure from the best fit King model for r>~8" - as a surface brightness
excess at large radii, and the star counts profile shows a clear break in
correspondence of the estimated tidal radius. Both features are interpreted as
the signature of the presence of extratidal stars around the cluster. We also
show that B514 has a half-light radius significantly larger than ordinary
globular clusters of the same luminosity. In the M_V vs. log r_h plane, B514
lies in a region inhabited by peculiar clusters, like Omega Cen, G1, NGC2419
and others, as well as by the nuclei of dwarf elliptical galaxies.


title:
The light variability of the helium strong star HD 37776 as a result of
  its inhomogeneous elemental surface distribution

abstract:
  We simulate light curves of the helium strong chemically peculiar star HD
37776 assuming that the observed periodic light variations originate as a
result of inhomogeneous horizontal distribution of chemical elements on the
surface of a rotating star. We show that chemical peculiarity influences the
monochromatic radiative flux, mainly due to bound-free processes. Using the
model of the distribution of silicon and helium on HD 37776 surface, derived
from spectroscopy, we calculate a photometric map of the surface and
consequently the uvby light curves of this star. Basically, the predicted light
curves agree in shape and amplitude with the observed ones. We conclude that
the basic properties of variability of this helium strong chemically peculiar
star can be understood in terms of the model of spots with peculiar chemical
composition.


title: Low-Scale Technicolor at the Tevatron and LHC

abstract:
  The Tevatron experiments CDF and DO are close to making definitive statements
about the technicolor discovery mode rho_T -> W pi_T for M(rho_T) <~ 230 GeV
and M(pi_T) <~ 125 GeV. We propose new incisive tests for this mode and
searches for others that may be feasible at the Tevatron and certainly are at
the LHC. The other searches include two long discussed, namely, omega_T ->
gamma pi_T and l+l-, and a new one -- for the I^G J^{PC} = 1^- 1^{++} partner,
a_T, of the rho_T. Adopting the argument that the technicolor contribution to S
is reduced if M(a_T) is near M(rho_T), we enumerate important a_T decays and
estimate production rates at the colliders.


title:
Hodge-Stickelberger polygons for L-functions of exponential sums of
  P(x^s)

abstract:
  Let P(x) be a one-variable Laurent polynomial of degree (d_1,d_2) over a
finite field of characteristic p. For any fixed positive integer s not
divisible by p, we prove that the (normalized) p-adic Newton polygon of the
L-functions of exponential sums of P(x^s) has a tight lower bound which we call
`Hodge-Stickelberger polygon', depending only on d_1,d_2,s, and (p mod s). This
Hodge-Stickelberger polygon is a weighted convolution of a `Hodge polygon' for
L-function of exponential sum of P(x) and the `Newton polygon' for L-function
of exponential sum of x^s (given by the classical Stickelberger theory). We
prove an analogous Hodge-Stickelberger lower bound for multivariable Laurent
polynomials as well.
  We prove this Hodge-Stickelberger polygon is the limit of generic Newton
polygons of P(x^s) in a sense that was made explicit in the paper.


title: Tri-Bimaximal Neutrino Mixing and the Family Symmetry Z_7 x Z_3

abstract:
  The Non-Abelian finite group PSL_2(7) is the only simple subgroup of SU(3)
with a complex three-dimensional irreducible representation. It has two maximal
subgroups, S_4 which, along with its own A_4 subgroup, has been successfully
applied in numerous models of flavor, as well as the 21 element Frobenius group
Z_7 x Z_3, which has gained much less attention. We show that it can also be
used to generate tri-bimaximal mixing in the neutrino sector, while allowing
for quark and charged lepton hierarchies.


title: Gravitational Wilson Loop and Large Scale Curvature

abstract:
  In a quantum theory of gravity the gravitational Wilson loop, defined as a
suitable quantum average of a parallel transport operator around a large
near-planar loop, provides important information about the large-scale
curvature properties of the geometry. Here we shows that such properties can be
systematically computed in the strong coupling limit of lattice regularized
quantum gravity, by performing a local average over rotations, using an assumed
near-uniform measure in group space. We then relate the resulting quantum
averages to an expected semi-classical form valid for macroscopic observers,
which leads to an identification of the gravitational correlation length
appearing in the Wilson loop with an observed large-scale curvature. Our
results suggest that strongly coupled gravity leads to a positively curved (De
Sitter-like) quantum ground state, implying a positive effective cosmological
constant at large distances.


title:
Nonlinear perturbations of Fuchsian systems: corrections and
  linearization, normal forms

abstract:
  Nonlinear perturbation of Fuchsian systems are studied in a region including
two singularities. It is proved that such systems are generally not
analytically equivalent to their linear part (they are not linearizable) and
the obstructions are found constructively, as a countable set of numbers.
Furthermore, assuming a polynomial character of the nonlinear part, it is shown
that there exists a unique formal "correction" of the nonlinear part so that
the "corrected" system is formally linearizable.
  Normal forms of these systems are found, providing also their classification.


title:
Detectors for the James Webb Space Telescope Near-Infrared Spectrograph
  I: Readout Mode, Noise Model, and Calibration Considerations

abstract:
  We describe how the James Webb Space Telescope (JWST) Near-Infrared
Spectrograph's (NIRSpec's) detectors will be read out, and present a model of
how noise scales with the number of multiple non-destructive reads
sampling-up-the-ramp. We believe that this noise model, which is validated
using real and simulated test data, is applicable to most astronomical
near-infrared instruments. We describe some non-ideal behaviors that have been
observed in engineering grade NIRSpec detectors, and demonstrate that they are
unlikely to affect NIRSpec sensitivity, operations, or calibration. These
include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real
test data, we show that the reset anomaly is: (1) very nearly noiseless and (2)
can be easily calibrated out. Likewise, we show that large-amplitude RTN
affects only a small and fixed population of pixels. It can therefore be
tracked using standard pixel operability maps.


title: Phenomenology from a U(1) gauged hidden sector

abstract:
  We consider the phenomenological consequences of a hidden Higgs sector
extending the Standard Model (SM), in which the matter content are uncharged
under the SM gauge groups. We consider a simple case where the hidden sector is
gauged under a U(1) with one Higgs singlet. The only couplings between SM and
the hidden sector are through mixings between the neutral gauge bosons of the
two respective sectors, and between the Higgs bosons. We find signals testable
at the LHC that can reveal the existence and shed light on the nature of such a
hidden sector.


title: Non-Gaussianity analysis on local morphological measures of WMAP data

abstract:
  The decomposition of a signal on the sphere with the steerable wavelet
constructed from the second Gaussian derivative gives access to the
orientation, signed-intensity, and elongation of the signal's local features.
In the present work, the non-Gaussianity of the WMAP temperature data of the
cosmic microwave background (CMB) is analyzed in terms of the first four
moments of the statistically isotropic random fields associated with these
local morphological measures, at wavelet scales corresponding to angular sizes
between 27.5 arcminutes and 30 degrees on the celestial sphere. While no
detection is made neither in the orientation analysis nor in the elongation
analysis, a strong detection is made in the excess kurtosis of the
signed-intensity of the WMAP data. The non-Gaussianity is observed with a
significance level below 0.5% at a wavelet scale corresponding to an angular
size around 10 degrees, and confirmed at neighbour scales. This supports a
previous detection of an excess of kurtosis in the wavelet coefficient of the
WMAP data with the axisymmetric Mexican hat wavelet (Vielva et al. 2004).
Instrumental noise and foreground emissions are not likely to be at the origin
of the excess of kurtosis. Large-scale modulations of the CMB related to some
unknown systematics are rejected as possible origins of the detection. The
observed non-Gaussianity may therefore probably be imputed to the CMB itself,
thereby questioning the basic inflationary scenario upon which the present
concordance cosmological model relies. Taking the CMB temperature angular power
spectrum of the concordance cosmological model at face value, further analysis
also suggests that this non-Gaussianity is not confined to the directions on
the celestial sphere with an anomalous signed-intensity.


title: On the cyclicity of weight-homogeneous centers

abstract:
  Let W be a weight-homogeneous planar polynomial differential system with a
center. We find an upper bound of the number of limit cycles which bifurcate
from the period annulus of W under a generic polynomial perturbation. We apply
this result to a particular family of planar polynomial systems having a
nilpotent center without meromorphic first integral.


title: Analytic linearization of nonlinear perturbations of Fuchsian systems

abstract:
  Nonlinear perturbation of Fuchsian systems are studied in regions including
two singularities. Such systems are not necessarily analytically equivalent to
their linear part (they are not linearizable). Nevertheless, it is shown that
in the case when the linear part has commuting monodromy, and the eigenvalues
have positive real parts, there exists a unique correction function of the
nonlinear part so that the corrected system becomes analytically linearizable.


title:
The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne Breakout Reaction and Impact on
  X-Ray Bursts

abstract:
  The breakout reaction $^{15}$O($\alpha,\gamma$)$^{19}$Ne, which regulates the
flow between the hot CNO cycle and the rp-process, is critical for the
explanation of the burst amplitude and periodicity of X-ray bursters. We report
on the first successful measurement of the critical $\alpha$-decay branching
ratios of relevant states in $^{19}$Ne populated via
$^{19}$F($^3$He,t)$^{19}$Ne. Based on the experimental results and our previous
lifetime measurements of these states, we derive the first experimental rate of
$^{15}$O($\alpha,\gamma$)$^{19}$Ne. The impact of our experimental results on
the burst pattern and periodicity for a range of accretion rates is analyzed.


title: Kummer subfields of tame division algebras over Henselian valued fields

abstract:
  By generalizing the method used by Tignol and Amitsur in [TA85], we determine
necessary and sufficient conditions for an arbitrary tame central division
algebra D over a Henselian valued field E to have Kummer subfields [Corollary
2.11 and Corollary 2.12]. We prove also that if D is a tame semiramified
division algebra of prime power degree p^n over E such that p\neq char(\bar E)
and rk(\Gamma_D/\Gamma_E)\geq 3 [resp., such that p\neq char(\bar E) and p^3
divides exp(\Gamma_D/\Gamma_E)], then D is non-cyclic [Proposition 3.1] [resp.,
D is not an elementary abelian crossed product [Proposition 3.2]].


title:
Probing the Relation Between X-ray-Derived and Weak-Lensing-Derived
  Masses for Shear-Selected Galaxy Clusters: I. A781

abstract:
  We compare X-ray and weak-lensing masses for four galaxy clusters that
comprise the top-ranked shear-selected cluster system in the Deep Lens Survey.
The weak-lensing observations of this system, which is associated with A781,
are from the Kitt Peak Mayall 4-m telescope, and the X-ray observations are
from both Chandra and XMM-Newton. For a faithful comparison of masses, we adopt
the same matter density profile for each method, which we choose to be an NFW
profile. Since neither the X-ray nor weak-lensing data are deep enough to well
constrain both the NFW scale radius and central density, we estimate the scale
radius using a fitting function for the concentration derived from cosmological
hydrodynamic simulations and an X-ray estimate of the mass assuming
isothermality. We keep this scale radius in common for both X-ray and
weak-lensing profiles, and fit for the central density, which scales linearly
with mass. We find that for three of these clusters, there is agreement between
X-ray and weak-lensing NFW central densities, and thus masses. For the other
cluster, the X-ray central density is higher than that from weak-lensing by 2
sigma. X-ray images suggest that this cluster may be undergoing a merger with a
smaller cluster. This work serves as an additional step towards understanding
the possible biases in X-ray and weak-lensing cluster mass estimation methods.
Such understanding is vital to efforts to constrain cosmology using X-ray or
weak-lensing cluster surveys to trace the growth of structure over cosmic time.


title:
Electron-acoustic-phonon scattering and electron relaxation in
  two-coupled quantum rings

abstract:
  Electron relaxation, induced by acoustic phonons, is studied for coupled
quantum rings in the presence of external fields, both electric and magnetic.
We address the problem of a single electron in vertically coupled GaAs quantum
rings. Electron-phonon interaction is accounted for both deformation potential
and piezoelectric field coupling mechanisms. Depending on the external fields,
the ring radii and the separation between the rings, we show that the two
different couplings have different weights and importance. Significant
oscillations are found in the scattering rates from electron excited states to
the ground state, as a function of either the geometry of the system or the
external fields.


title:
Modeling partitioning of Min proteins between daughter cells after
  septation in Escherichia coli

abstract:
  Ongoing sub-cellular oscillation of Min proteins is required to block
minicelling in E. coli. Experimentally, Min oscillations are seen in newly
divided cells and no minicells are produced. In model Min systems many daughter
cells do not oscillate following septation because of unequal partitioning of
Min proteins between the daughter cells. Using the 3D model of Huang et al., we
investigate the septation process in detail to determine the cause of the
asymmetric partitioning of Min proteins between daughter cells. We find that
this partitioning problem arises at certain phases of the MinD and MinE
oscillations with respect to septal closure and it persists independently of
parameter variation. At most 85% of the daughter cells exhibit Min oscillation
following septation. Enhanced MinD binding at the static polar and dynamic
septal regions, consistent with cardiolipin domains, does not substantially
increase this fraction of oscillating daughters. We believe that this problem
will be shared among all existing Min models and discuss possible biological
mechanisms that may minimize partitioning errors of Min proteins following
septation.


title:
FPTAS for optimizing polynomials over the mixed-integer points of
  polytopes in fixed dimension

abstract:
  We show the existence of a fully polynomial-time approximation scheme (FPTAS)
for the problem of maximizing a non-negative polynomial over mixed-integer sets
in convex polytopes, when the number of variables is fixed. Moreover, using a
weaker notion of approximation, we show the existence of a fully
polynomial-time approximation scheme for the problem of maximizing or
minimizing an arbitrary polynomial over mixed-integer sets in convex polytopes,
when the number of variables is fixed.


title: Supergravity origin of the MSSM inflation

abstract:
  We consider the supergravity origin of the recently proposed MSSM
inflationary model, which relies on the existence of a saddle point along a
dimension six flat direction. We derive the conditions that the Kahler
potential has to satisfy for the saddle point to exist irrespective of the
hidden sector vevs. We show that these conditions are satisfied by a simple
class of Kahler potentials, which we find to have a similar form as in various
string theory compactifications. For these potentials, slow roll MSSM inflation
requires no fine tuning of the soft supersymmetry breaking parameters.


title: Anonymous quantum communication

abstract:
  We present the first protocol for the anonymous transmission of a quantum
state that is information-theoretically secure against an active adversary,
without any assumption on the number of corrupt participants. The anonymity of
the sender and receiver is perfectly preserved, and the privacy of the quantum
state is protected except with exponentially small probability. Even though a
single corrupt participant can cause the protocol to abort, the quantum state
can only be destroyed with exponentially small probability: if the protocol
succeeds, the state is transferred to the receiver and otherwise it remains in
the hands of the sender (provided the receiver is honest).


title: Charm-quark fragmentation with an effective coupling constant

abstract:
  We use a recently proposed non-perturbative model, based on an effective
strong coupling constant and free from tunable parameters, to study c-flavoured
hadron production in e+e- annihilation. Charm-quark production is described in
the framework of perturbative fragmentation functions, with NLO coefficient
functions, NLL non-singlet DGLAP evolution and NNLL large-x resummation. We
model hadronization effects by means of the effective coupling constant in the
NNLO approximation and compare our results with experimental data taken at the
Z0 pole and at the Upsilon(4S) resonance. We find that, within the experimental
and theoretical uncertainties, our model is able to give a reasonable
description of D*+-meson spectra from ALEPH for x<1-Lambda/m_c. More serious
discrepancies are instead present when comparing with D and D^* data from BELLE
and CLEO in x-space. Within the errors, our model is nonetheless capable of
reproducing the first ten Mellin moments of all considered data sets. However,
the fairly large theoretical uncertainties call for a full NNLO/NNLL analysis.


title: Measurement of the Lambda_b lifetime using semileptonic decays

abstract:
  We report a measurement of the Lambda_b lifetime using a sample corresponding
to 1.3 fb$^{-1}$ of data collected by the D0 experiment in 2002--2006 during
Run II of the Fermilab Tevatron collider. The Lambda_b baryon is reconstructed
via the decay Lambda_b -> mu nu Lambda_c X. Using $4437 \pm 329$ signal
candidates, we measure the Lambda_b lifetime to be $\tau(Lambda_b)$ =
1.290^{+0.119}_{-0.110}(stat) ^{+0.087}_{-0.091} (syst) ps, which is among the
most precise measurements in semileptonic Lambda_b decays. This result is in
good agreement with the world average value.


title: Electronic compressibility of a graphene bilayer

abstract:
  We calculate the electronic compressibility arising from electron-electron
interactions for a graphene bilayer within the Hartree-Fock approximation. We
show that, due to the chiral nature of the particles in this system, the
compressibility is rather different from those of either the two-dimensional
electron gas or ordinary semiconductors. We find that an inherent competition
between the contributions coming from intra-band exchange interactions
(dominant at low densities) and inter-band interactions (dominant at moderate
densities) leads to a non-monotonic behavior of the compressibility as a
function of carrier density.


title:
Magnetorotational collapse of very massive stars to black holes in full
  general relativity

abstract:
  We perform axisymmetric simulations of the magnetorotational collapse of very
massive stars in full general relativity. Our simulations are applicable to the
collapse of supermassive stars (M > 10^3M_sun) and to very massive Pop III
stars. We model our initial configurations by n=3 polytropes. The ratio of
magnetic to rotational kinetic energy in these configurations is chosen to be
small (1% and 10%). We find that such magnetic fields do not affect the initial
collapse significantly. The core collapses to a black hole, after which black
hole excision is employed to continue the evolution long enough for the hole to
reach a quasi-stationary state. We find that the black hole mass is M_h = 0.95M
and its spin parameter is J_h/M_h^2 = 0.7, with the remaining matter forming a
torus around the black hole. We freeze the spacetime metric ("Cowling
approximation") and continue to follow the evolution of the torus after the
black hole has relaxed to quasi-stationary equilibrium. In the absence of
magnetic fields, the torus settles down following ejection of a small amount of
matter due to shock heating. When magnetic fields are present, the field lines
gradually collimate along the hole's rotation axis. MHD shocks and the MRI
generate MHD turbulence in the torus and stochastic accretion onto the central
black hole. When the magnetic field is strong, a wind is generated in the
torus, and the torus undergoes radial oscillations that drive episodic
accretion onto the hole. These oscillations produce long-wavelength
gravitational waves potentially detectable by LISA. The final state of the
magnetorotational collapse always consists of a central black hole surrounded
by a collimated magnetic field and a hot, thick accretion torus. This system is
a viable candidate for the central engine of a long-soft gamma-ray burst.


title:
A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula
  Cluster from Very Long Baseline Array Observations

abstract:
  We determine the parallax and proper motion of the flaring, non-thermal radio
star GMR A, a member of the Orion Nebula Cluster, using Very Long Baseline
Array observations. Based on the parallax, we measure a distance of 389 +24/-21
parsecs to the source. Our measurement places the Orion Nebula Cluster
considerably closer than the canonical distance of 480 +/- 80 parsecs
determined by Genzel et al. (1981). A change of this magnitude in distance
lowers the luminosities of the stars in the cluster by a factor of ~ 1.5. We
briefly discuss two effects of this change--an increase in the age spread of
the pre-main sequence stars and better agreement between the zero-age
main-sequence and the temperatures and luminosities of massive stars.


title:
Magnetization plateaus and sublattice ordering in easy axis Kagome
  lattice antiferromagnets

abstract:
  We study kagome lattice antiferromagnets where the effects of easy axis
single-ion anisotropy ($D$) dominates over the Heisenberg exchange $J$. For $S
\ge 3/2$, virtual quantum fluctuations help lift the extensive classical
degeneracy. We demonstrate the presence of a one-third magnetization plateau
for a broad range of magnetic fields $J^3/D^2 \lesssim B \lesssim JS$ along the
easy axis. The fully equilibriated system at low temperature on this plateau
develops an unusual {\em nematic} order that breaks sublattice rotation
symmetry but not translation symmetry--however, extremely slow dynamics
associated with this ordering is expected to lead to glassy freezing of the
system on intermediate time-scales.


title: Dying Dyons Don't Count

abstract:
  The dyonic 1/4-BPS states in 4D string theory with N=4 spacetime
supersymmetry are counted by a Siegel modular form. The pole structure of the
modular form leads to a contour dependence in the counting formula obscuring
its duality invariance. We exhibit the relation between this ambiguity and the
(dis-)appearance of bound states of 1/2-BPS configurations. Using this insight
we propose a precise moduli-dependent contour prescription for the counting
formula. We then show that the degeneracies are duality-invariant and are
correctly adjusted at the walls of marginal stability to account for the
(dis-)appearance of the two-centered bound states. Especially, for large black
holes none of these bound states exists at the attractor point and none of
these ambiguous poles contributes to the counting formula. Using this fact we
also propose a second, moduli-independent contour which counts the "immortal
dyons" that are stable everywhere.


title:
Super Star Cluster NGC1705-1: A Local Analogue to the Birthsite of
  Long-duration Gamma-ray Bursts

abstract:
  Recent observations suggest that global properties of the host galaxies for
long-duration gamma-ray bursts (GRBs) are particularly well-suited for creating
the massive star progenitors of these GRBs. Motivated by the hypothesis that
massive young star clusters located in metal-poor, low-metallicity galaxies are
a natural birthsite for GRB progenitors, we present a comparison study of the
ISM properties along the sightline toward the super star cluster, NGC1705-1,
and those in distant GRB hosts. Using the same set of metal transitions in the
UV and applying known ISM structures in NGC1705, we find that NGC1705-1
resembles distant GRB host galaxies in its high neutral gas column, low
molecular gas fraction, low metallicity, alpha-element enhancement,and low dust
depletion. The lack of molecular gas is due to the enhanced UV radiation field
in the starburst environment, consistent with the expectations for GRB
progenitors. In addition, the known presence of dense neutral gas clouds at
r<500 pc from NGC1705-1 provides a natural reservoir of C^+, Si^+, and Fe^+
ions that may be subsequently excited by the afterglow UV radiation field to
produce excited lines commonly seen in GRB host ISM. We further argue that the
apparent offset in the velocity profiles of low- and high-ionization
transitions from absorption-line observations alone already offers important
clues for related starburst episodes in GRB host galaxies. Our study shows that
a statistical comparison between the ISM around star clusters and high-redshift
GRB progenitors is important for identifying the key physical parameters that
facilitate the formation of GRBs.


title: Chain motifs: The tails and handles of complex networks

abstract:
  Great part of the interest in complex networks has been motivated by the
presence of structured, frequently non-uniform, connectivity. Because diverse
connectivity patterns tend to result in distinct network dynamics, and also
because they provide the means to identify and classify several types of
complex networks, it becomes important to obtain meaningful measurements of the
local network topology. In addition to traditional features such as the node
degree, clustering coefficient and shortest path, motifs have been introduced
in the literature in order to provide complementary description of the networks
connectivity. The current work proposes a new type of motifs, namely chains of
nodes, namely sequences of connected nodes with degree two. These chains have
been subdivided into cords, tails, rings and handles, depending on the type of
their extremities (e.g. open or connected). A theoretical analysis of the
density of such motifs in random and scale free networks is described, and an
algorithm for identifying those motifs in general networks is presented. The
potential of considering chains for network characterization has been
illustrated with respect to five categories of real-world networks including 16
cases. Several interesting findings were obtained, including the fact that
several chains were observed in the real-world networks, especially the WWW,
books, and power-grid. The possibility of chains resulting from incompletely
sampled networks is also investigated.


title: Theoretical study of ferroelectric potassium nitrate

abstract:
  We present a detailed study of the structural behavior and polarization
reversal mechanism in phase III of KNO$_3$, an unusual ferroelectric material
in which the nitrate groups rotate during polarization reversal. This material
was one of several studied in a previous work [O. Di\'eguez and D. Vanderbilt,
Phys. Rev. Lett. {\bf 96}, 056401 (2006)] where methods were described for
computing curves of energy versus electric polarization. In the present work we
extend and systematize the previous first-principles calculations on KNO$_3$,
and analyze in detail a two-parameter model in which the energy of the system
is written as a low-order expansion in the polarization and the nitrate group
orientation. We confirm that this model reproduces the first-principles results
for KNO$_3$ very well and construct its parameter-space phase diagram,
describing regions where unusual triple-well potentials appear. We also present
first-principles calculations of KNO$_3$ under pressure, finding that its
energy-versus-polarization curves change character by developing a
first-derivative discontinuity at zero polarization.


title:
Weyssenhoff fluid dynamics in general relativity using a 1+3 covariant
  approach

abstract:
  The Weyssenhoff fluid is a perfect fluid with spin where the spin of the
matter fields is the source of torsion in an Einstein-Cartan framework. Obukhov
and Korotky showed that this fluid can be described as an effective fluid with
spin in general relativity. A dynamical analysis of such a fluid is performed
in a gauge invariant manner using the 1+3 covariant approach. This yields the
propagation and constraint equations for the set of dynamical variables. A
verification of these equations is performed for the special case of
irrotational flow with zero peculiar acceleration by evolving the constraints.


title: A Note on Carleman's Inequality

abstract:
  We study a weighted version of Carleman's inequality via Carleman's original
approach. As an application of our result, we prove a conjecture of Bennett.


title: Surface Operators and Knot Homologies

abstract:
  Topological gauge theories in four dimensions which admit surface operators
provide a natural framework for realizing homological knot invariants. Every
such theory leads to an action of the braid group on branes on the
corresponding moduli space. This action plays a key role in the construction of
homological knot invariants. We illustrate the general construction with
examples based on surface operators in N=2 and N=4 twisted gauge theories which
lead to a categorification of the Alexander polynomial, the equivariant knot
signature, and certain analogs of the Casson invariant.
  This paper is based on a lecture delivered at the International Congress on
Mathematical Physics 2006, Rio de Janeiro, and at the RTN Workshop 2006,
Napoli.


title: Strange attractors in periodically-kicked degenerate Hopf bifurcations

abstract:
  We prove that spiral sinks (stable foci of vector fields) can be transformed
into strange attractors exhibiting sustained, observable chaos if subjected to
periodic pulsatile forcing. We show that this phenomenon occurs in the context
of periodically-kicked degenerate supercritical Hopf bifurcations. The results
and their proofs make use of a new multi-parameter version of the theory of
rank one maps developed by Wang and Young.


title:
The rotating Morse potential model for diatomic molecules in the
  tridiagonal J-matrix representation: I. Bound states

abstract:
  This is the first in a series of articles in which we study the rotating
Morse potential model for diatomic molecules in the tridiagonal J-matrix
representation. Here, we compute the bound states energy spectrum by
diagonalizing the finite dimensional Hamiltonian matrix of H2, LiH, HCl and CO
molecules for arbitrary angular momentum. The calculation was performed using
the J-matrix basis that supports a tridiagonal matrix representation for the
reference Hamiltonian. Our results for these diatomic molecules have been
compared with available numerical data satisfactorily. The proposed method is
handy, very efficient, and it enhances accuracy by combining analytic power
with a convergent and stable numerical technique.


title: Prym varieties and applications

abstract:
  The classical definition of Prym varieties deals with the unramified covers
of curves. The aim of the present paper is to give explicit algebraic
descriptions of the Prym varieties associated to ramified double covers of
algebraic curves. We make a careful study of the connection with the concept of
algebraic completely integrable systems and we apply the methods to some
problems of Mathematical Physics.