title: Spatial decoherence factor via the qubit-field interaction

abstract:
  We analyze the time evolution of an initial spatial coherence for a two level
atom whose internal degrees of freedom interact with a single mode of a cavity
field. When the qubit-field subsystem is taken as an environment, the
translational dynamics experiences a decoherence process which may be encoded
in a decoherence factor D. We find that the field statistics affects D through
the alternative paths the system-environment may follow along their
entanglement, while eventual field phase properties give rise to an imaginary
part of D which is related to the atomic translation. From the decoherence
perspective, we analyze the relation between the atomic momentum and the
imaginary part of the atomic spatial density matrix, and some considerations on
its asymptotic behavior are brought into question at the conclusion of the
paper.


title:
Collective oscillations of a Fermi gas in the unitarity limit:
  Temperature effects and the role of pair correlations

abstract:
  We present detailed measurements of the frequency and damping of three
different collective modes in an ultracold trapped Fermi gas of $^6$Li atoms
with resonantly tuned interactions. The measurements are carried out over a
wide range of temperatures. We focus on the unitarity limit, where the
scattering length is much greater than all other relevant length scales. The
results are compared to theoretical calculations that take into account Pauli
blocking and pair correlations in the normal state above the critical
temperature for superfluidity. We show that these two effects nearly compensate
each other and the behavior of the gas is close to the one of a classical gas.


title: Aspects of Causality in the Parallelisable Implicit Evolution Scheme

abstract:
  A (3+1)-evolutionary method in the framework of Regge Calculus, essentially a
method of approximating manifolds with rigid simplices, makes an excellent tool
to probe the evolution of manifolds with non-trivial topology or devoid of
symmetry. The "Parallelisable Implicit Evolution Scheme" is one such method.
Causality however, is an aspect of this method that has been barely
investigated. In this paper, we show how causality can be accounted for in this
evolutionary scheme. The revised algorithm is illustrated by a preliminary
application to a skeletonised spherical Friedmann-Lema\^itre-Robertson-Walker
universe.


title: Casimir Energy of a BEC: From Moderate Interactions to the Ideal Gas

abstract:
  Considering the Casimir effect due to phononic excitations of a weakly
interacting dilute {BEC}, we derive a re-normalized expression for the zero
temperature Casimir energy $\mathcal{E}_c$ of a {BEC} confined to a parallel
plate geometry with periodic boundary conditions. Our expression is formally
equivalent to the free energy of a bosonic field at finite temperature, with a
nontrivial density of modes that we compute analytically. As a function of the
interaction strength, $\mathcal{E}_c$ smoothly describes the transition from
the weakly interacting Bogoliubov regime to the non-interacting ideal {BEC}.
For the weakly interacting case, $\mathcal{E}_c$ reduces to leading order to
the Casimir energy due to zero-point fluctuations of massless phonon modes. In
the limit of an ideal Bose gas, our result correctly describes the Casimir
energy going to zero.


title: Anisotropic geometrodynamics in cosmological problems

abstract:
  The gravitation theory is modified on the base of geometric identity and
equivalence principle. This makes it possible to generalize the geodesics and
solve several problems of classical GRT such as flat rotation curves of the
spiral galaxies, Tully-Fisher law and some others and reveal the fundamental
(geometrical) origin of the cH acceleration value. The developed approach
contains all the results of the classical GRT and has promising cosmological
consequences.


title:
The giant vortex state for a Bose-Einstein condensate in a rotating
  anharmonic trap : extreme rotation regimes

abstract:
  We study the fast rotation limit for a Bose-Einstein condensate in a
quadratic plus quartic confining potential within the framework of the two
dimensional Gross-Pitaevskii energy functional. As the rotation speed tends to
infinity with a proper scaling of the other parameters in the model, a linear
limit problem appears for which we are able to derive precise energy estimates.
We prove that the energy and density asymptotics of the problem can be obtained
by minimizing a simplified one dimensional energy functional. In the case of a
fixed coupling constant we also prove that a giant vortex state appears. It is
an annulus with pure irrotational flow encircling a central low-density hole
around which there is a macroscopic phase circulation.


title: On lensing by a cosmological constant

abstract:
  Several recent papers have suggested that the cosmological constant Lambda
directly influences the gravitational deflection of light. We place this
problem in a cosmological context, deriving an expression for the linear
potentials which control the cosmological bending of light, finding that it has
no explicit dependence on the cosmological constant. To explore the physical
origins of the apparent Lambda-dependent potential that appears in the static
Kottler metric, we highlight the two classical effects which lead to the
aberration of light. The first relates to the observer's motion relative to the
source, and encapsulates the familiar concept of angular-diameter distance. The
second term, which has proved to be the source of debate, arises from cosmic
acceleration, but is rarely considered since it vanishes for photons with
radial motion. This apparent form of light-bending gives the appearance of
curved geodesics even within a flat and homogeneous universe. However this
cannot be construed as a real lensing effect, since its value depends on the
observer's frame of reference. Our conclusion is thus that standard results for
gravitational lensing in a universe containing Lambda do not require
modification, with any influence of Lambda being restricted to negligible
high-order terms.


title: Extended Thomas-Fermi Density Functional for the Unitary Fermi Gas

abstract:
  We determine the energy density $\xi (3/5) n \epsilon_F$ and the gradient
correction $\lambda \hbar^2(\nabla n)^2/(8m n)$ of the extended Thomas-Fermi
(ETF) density functional, where $n$ is number density and $\epsilon_F$ is Fermi
energy, for a trapped two-components Fermi gas with infinite scattering length
(unitary Fermi gas) on the basis of recent diffusion Monte Carlo (DMC)
calculations [Phys. Rev. Lett. {\bf 99}, 233201 (2007)]. In particular we find
that $\xi=0.455$ and $\lambda=0.13$ give the best fit of the DMC data with an
even number $N$ of particles. We also study the odd-even splitting $\gamma
N^{1/9} \hbar \omega$ of the ground-state energy for the unitary gas in a
harmonic trap of frequency $\omega$ determining the constant $\gamma$. Finally
we investigate the effect of the gradient term in the time-dependent ETF model
by introducing generalized Galilei-invariant hydrodynamics equations.


title: Abstract integration, Combinatorics of Trees and Differential Equations

abstract:
  This is a review paper on recent work about the connections between rough
path theory, the Connes-Kreimer Hopf algebra on rooted trees and the analysis
of finite and infinite dimensional differential equation. We try to explain and
motivate the theory of rough paths introduced by T. Lyons in the context of
differential equations in presence of irregular noises. We show how it is used
in an abstract algebraic approach to the definition of integrals over paths
which involves a cochain complex of finite increments. In the context of such
abstract integration theories we outline a connection with the combinatorics of
rooted trees. As interesting examples where these ideas apply we present two
infinite dimensional dynamical systems: the Navier-Stokes equation and the
Korteweg-de-Vries equation.


title: Iterated amplitudes in the high-energy limit

abstract:
  We consider the high-energy limits of the colour ordered four-, five- and
six-gluon MHV amplitudes of the maximally supersymmetric QCD in the multi-Regge
kinematics where all the gluons are strongly ordered in rapidity. We show that
various building blocks occurring in the Regge factorisation (the Regge
trajectory, the coefficient functions and the Lipatov vertex) satisfy an
iterative structure very similar to the Bern-Dixon-Smirnov (BDS) ansatz. This
iterative structure, combined with the universality of the building blocks,
enables us to show that in the Euclidean region any two- and three-loop
amplitude in multi-Regge kinematics is guaranteed to satisfy the BDS ansatz. We
also consider slightly more general kinematics where the strong rapidity
ordering applies to all the gluons except the two with either the largest or
smallest rapidities, and we derive the iterative formula for the associated
coefficient function. We show that in this kinematic limit the BDS ansatz is
also satisfied. Finally, we argue that only for more general kinematics - e.g.
with three gluons having similar rapidities, or where the two central gluons
have similar rapidities - can a disagreement with the BDS ansatz arise.


title: Conceal an entrance by means of superscatterer

abstract:
  By using the novel property of the rectangular superscatterer, we propose a
design which can conceal an entrance from electromagnetic wave detection. Such
a superscatterer is realized by coating a negative index material shell on a
perfect electrical conductor rectangle cylinder. The results are numerically
confirmed by full-wave simulations both in the far-field and near-field.


title: A Markov model for the spread of Hepatitis C

abstract:
  We propose a Markov model for the spread of Hepatitis C virus (HCV) among
drug users who use injections. We then proceed to an asymptotic analysis (large
initial population) and show that the Markov process is close to the solution
of a non linear autonomous differential system. We prove both a law of large
numbers and functional central limit theorem to precise the speed of
convergence towards the limiting system. The deterministic system itself
converges, as time goes to infinity, to an equilibrium point. This corroborates
the empirical observations about the prevalence of HCV.


title: Fainter and closer: finding planets by symmetry breaking

abstract:
  Imaging of planets is very difficult, due to the glare from their nearby,
much brighter suns. Static and slowly-evolving aberrations are the limiting
factors, even after application of adaptive optics. The residual speckle
pattern is highly symmetrical due to diffraction from the telescope's aperture.
We suggest to break this symmetry and thus to locate planets hidden beneath it.
An eccentric pupil mask is rotated to modulate the residual light pattern not
removed by other means. This modulation is then exploited to reveal the
planet's constant signal. In well-corrected ground-based observations we can
reach planets six stellar magnitudes fainter than their sun, and only 2-3 times
the diffraction limit from it. At ten times the diffraction limit, we detect
planets 16 magnitudes fainter. The stellar background drops by five magnitudes.


title: On semidefinite representations of plane quartics

abstract:
  This note focuses on the problem of representing convex sets as projections
of the cone of positive semidefinite matrices, in the particular case of sets
generated by bivariate polynomials of degree four. Conditions are given for the
convex hull of a plane quartic to be exactly semidefinite representable with at
most 12 lifting variables. If the quartic is rationally parametrizable, an
exact semidefinite representation with 2 lifting variables can be obtained.
Various numerical examples illustrate the techniques and suggest further
research directions.


title:
Probing two Universal Extra Dimension model with leptons and photons at
  the LHC and ILC

abstract:
  We discuss the collider signatures of electroweak (1,0)-mode excitations in
the framework of two universal extra dimension (2UED) at the LHC and ILC. In
general, pair production of electroweak (1,0)-mode particles of 2UED gives rise
to multi lepton plus missing transverse momentum signal. Upto 1/R = 400 GeV two
lepton plus missing transverse momentum signal and upto 1/R = 600 GeV three
lepton plus missing transverse momentum signal stands over the $5\sigma$
standard deviation of the Standard Model background at the LHC with $100
fb^{-1}$ integrated luminosity. At ILC we study single photon plus missing
energy signal from the production of U(1) gauge boson in association with a
U(1) spinless adjoint. With proper choice of beam polarization, signal strength
is greater than $5\sigma$ standard deviation of the Standard Model background
almost upto the kinematic limit of the collider.


title: Diametral Pairs of Linear Extensions

abstract:
  Given a finite poset P, we consider pairs of linear extensions of P with
maximal distance, where the distance between two linear extensions L_1, L_2 is
the number of pairs of elements of P appearing in different orders in L_1 and
L_2. A diametral pair maximizes the distance among all pairs of linear
extensions of P. Felsner and Reuter defined the linear extension diameter of P
as the distance between a diametral pair of linear extensions.
  We show that computing the linear extension diameter is NP-complete in
general, but can be solved in polynomial time for posets of width 3.
  Felsner and Reuter conjectured that, in every diametral pair, at least one of
the linear extensions reverses a critical pair. We construct a counterexample
to this conjecture. On the other hand, we show that a slightly stronger
property holds for many classes of posets: We call a poset "diametrally
reversing" if, in every diametral pair, both linear extensions reverse a
critical pair. Among other results we show that interval orders and 3-layer
posets are diametrally reversing. From the latter it follows that almost all
posets are diametrally reversing.


title: Commissioning Run of the CRESST-II Dark Matter Search

abstract:
  The CRESST cryogenic direct dark matter search at Gran Sasso, searching for
WIMPs via nuclear recoil, has been upgraded to CRESST-II by several changes and
improvements.We present the results of a commissioning run carried out in 2007.
  The basic element of CRESST-II is a detector module consisting of a large (~
300 g) CaWO_4 crystal and a very sensitive smaller (~ 2 g) light detector to
detect the scintillation light from the CaWO_4.Information from light-quenching
factor studies allows the definition of a region of the energy-light yield
plane which corresponds to tungsten recoils. A neutron test is reported which
supports the principle of using the light yield to identify the recoiling
nucleus.
  Data obtained with two detector modules for a total exposure of 48 kg-days
are presented. Judging by the rate of events in the "all nuclear recoils"
acceptance region the apparatus shows a factor ~ten improvement with respect to
previous results, which we attribute principally to the presence of the neutron
shield.
  In the "tungsten recoils" acceptance region three events are found,
corresponding to a rate of 0.063 per kg-day. Standard assumptions on the dark
matter flux, coherent or spin independent interactions,then yield a limit for
WIMP-nucleon scattering of 4.8 \times 10^{-7}pb, at M{WIMP} ~50 GeV.


title:
Calculation of Asymptotic and RMS Kicks Due To Higher Order Modes in the
  3.9GHz Cavity

abstract:
  FLASH plans to use a "third harmonic" (3.9GHz) superconducting cavity to
compensate nonlinear distortions of the longitudinal phase space due to the
sinusoidal curvature of the the cavity voltage of the TESLA 1.3GHz cavities.
Higher order modes (HOMs) in the 3.9GHz have a significant impact on the
dynamics of the electron bunches in a long bunch train. Kicks due to dipole
modes can be enhanced along the bunch train depending on the frequency and
Q-value of the modes. The enhancement factor for a constant beam offset with
respect to the cavity has been calculated. A simple Monte Carlo model of these
effects, allowing for scatter in HOM frequencies due to manufacturing
variances, has also been implemented and results for both FLASH and for an
XFEL-like configuration are presented.


title:
First measurement of the Head-Tail directional nuclear recoil signature
  at energies relevant to WIMP dark matter searches

abstract:
  We present first evidence for the so-called Head-Tail asymmetry signature of
neutron-induced nuclear recoil tracks at energies down to 1.5 keV/amu using the
1m^3 DRIFT-IIc dark matter detector. This regime is appropriate for recoils
induced by Weakly Interacting Massive Particle (WIMPs) but one where the
differential ionization is poorly understood. We show that the distribution of
recoil energies and directions induced here by Cf-252 neutrons matches well
that expected from massive WIMPs. The results open a powerful new means of
searching for a galactic signature from WIMPs.


title: Glimpses on the micro black hole Planck phase

abstract:
  Mass thresholds, lifetimes, entropy and heat capacity for micro black holes
close to their late Schwarzschild phase are computed using two different
generalized uncertainty principles, in the framework of models with extra
spatial dimensions. Emissions of both photons and gravitons (in the bulk) are
taken into account. Results are discussed and compared.


title:
Fast GPU Implementation of Sparse Signal Recovery from Random
  Projections

abstract:
  We consider the problem of sparse signal recovery from a small number of
random projections (measurements). This is a well known NP-hard to solve
combinatorial optimization problem. A frequently used approach is based on
greedy iterative procedures, such as the Matching Pursuit (MP) algorithm. Here,
we discuss a fast GPU implementation of the MP algorithm, based on the recently
released NVIDIA CUDA API and CUBLAS library. The results show that the GPU
version is substantially faster (up to 31 times) than the highly optimized CPU
version based on CBLAS (GNU Scientific Library).


title: Convergence rates for an optimally controlled Ginzburg-Landau equation

abstract:
  An optimal control problem related to the probability of transition between
stable states for a thermally driven Ginzburg-Landau equation is considered.
The value function for the optimal control problem with a spatial
discretization is shown to converge quadratically to the value function for the
original problem. This is done by using that the value functions solve similar
Hamilton-Jacobi equations, the equation for the original problem being defined
on an infinite dimensional Hilbert space. Time discretization is performed
using the Symplectic Euler method. Imposing a reasonable condition this method
is shown to be convergent of order one in time, with a constant independent of
the spatial discretization.


title: Multiferroic Properties of Nanocrystalline BaTiO3

abstract:
  Some of the Multiferroics [1] form a rare class of materials that exhibit
magnetoelectric coupling arising from the coexistence of ferromagnetism and
ferroelectricity, with potential for many technological applications.[2,3] Over
the last decade, an active research on multiferroics has resulted in the
identification of a few routes that lead to multiferroicity in bulk
materials.[4-6] While ferroelectricity in a classic ferroelectric such as
BaTiO3 is expected to diminish with the reducing particle size,[7,8]
ferromagnetism cannot occur in its bulk form.[9] Here, we use a combination of
experiment and first-principles simulations to demonstrate that multiferroic
nature emerges in intermediate size nanocrystalline BaTiO3, ferromagnetism
arising from the oxygen vacancies at the surface and ferroelectricity from the
core. A strong coupling between a surface polar phonon and spin is shown to
result in a magnetocapacitance effect observed at room temperature, which can
open up possibilities of new electro-magneto-mechanical devices at the
nano-scale.


title:
The complexity of counting solutions to Generalised Satisfiability
  Problems modulo k

abstract:
  Generalised Satisfiability Problems (or Boolean Constraint Satisfaction
Problems), introduced by Schaefer in 1978, are a general class of problem which
allow the systematic study of the complexity of satisfiability problems with
different types of constraints. In 1979, Valiant introduced the complexity
class parity P, the problem of counting the number of solutions to NP problems
modulo two. Others have since considered the question of counting modulo other
integers.
  We give a dichotomy theorem for the complexity of counting the number of
solutions to Generalised Satisfiability Problems modulo integers. This follows
from an earlier result of Creignou and Hermann which gave a counting dichotomy
for these types of problem, and the dichotomy itself is almost identical.
Specifically, counting the number of solutions to a Generalised Satisfiability
Problem can be done in polynomial time if all the relations are affine.
Otherwise, except for one special case with k = 2, it is #_kP-complete.


title: The influence of charge detection on counting statistics

abstract:
  We consider the counting statistics of electron transport through a double
quantum dot with special emphasis on the dephasing induced by a nearby charge
detector. The double dot is embedded in a dissipative enviroment, and the
presence of electrons on the double dot is detected with a nearby quantum point
contact. Charge transport through the double dot is governed by a non-Markovian
generalized master equation. We describe how the cumulants of the current can
be obtained for such problems, and investigate the difference between the
dephasing mechanisms induced by the quantum point contact and the coupling to
the external heat bath. Finally, we consider various open questions of
relevance to future research.


title:
Fine structure and optical pumping of spins in individual semiconductor
  quantum dots

abstract:
  We review spin properties of semiconductor quantum dots and their effect on
optical spectra. Photoluminescence and other types of spectroscopy are used to
probe neutral and charged excitons in individual quantum dots with high
spectral and spatial resolution. Spectral fine structure and polarization
reveal how quantum dot spins interact with each other and with their
environment. By taking advantage of the selectivity of optical selection rules
and spin relaxation, optical spin pumping of the ground state electron and
nuclear spins is achieved. Through such mechanisms, light can be used to
process spins for use as a carrier of information.


title: Almeida-Thouless transition below six dimensions

abstract:
  The existence of an Almeida-Thouless (AT) instability surface below the upper
critical dimension 6 is demonstrated in the generic replica symmetric field
theory. Renormalization flows from around the zero-field fixed point are
investigated. By introducing the temperature and magnetic field dependence of
the bare parameters, the fate of the AT line can be followed from mean field
(infinite dimensions) down to d<6.


title:
Asymptotic tail properties of the distributions in the class of
  dispersion models

abstract:
  The class of dispersion models introduced by J{\o}rgensen (1997b) covers many
known distributions such as the normal, Student t, gamma, inverse Gaussian,
hyperbola, von-Mises, among others. We study the small dispersion asymptotic
(J{\o}rgensen, 1987b) behavior of the probability density functions of
dispersion models which satisfy the uniformly convergent saddlepoint
approximation. Our results extend those obtained by Finner et al. (2008).


title: Discovery of lake-effect clouds on Titan

abstract:
  Images from instruments on Cassini as well as from telescopes on the ground
reveal the presence of sporadic small-scale cloud activity in the cold
late-winter north polar of Saturn's large moon Titan. These clouds lie
underneath the previously discovered uniform polar cloud attributed to a
quiescent ethane cloud at ~40 km and appear confined to the same latitudes as
those of the largest known hydrocarbon lakes at the north pole of Titan. The
physical properties of these clouds suggest that they are due to methane
convection and condensation. Such convection has not been predicted for the
cold winter pole, but can be caused by a process in many ways analogous to
terrestrial lake-effect clouds. The lakes on Titan are a key connection between
the surface and the meteorological cycle.


title: Breathing patterns in nonlinear relaxation

abstract:
  In numerical experiments involving nonlinear solitary waves propagating
through nonhomogeneous media one observes "breathing" in the sense of the
amplitude of the wave going up and down on a much faster scale than the motion
of the wave. In this paper we investigate this phenomenon in the simplest case
of stationary waves in which the evolution corresponds to relaxation to a
nonlinear ground state. The particular model is the popular $ \delta_0 $
impurity in the cubic nonlinear Schroedinger equation on the line. We give
asymptotics of the amplitude on a finite but relevant time interval and show
their remarkable agreement with numerical experiments. We stress the nonlinear
origin of the "breathing patterns" caused by the selection of the ground state
depending on the initial data, and by the non-normality of the linearized
operator.


title: Beyond the Standard Model at the Tevatron and the LHC

abstract:
  This contribution contains a brief review of several scenarios for physics
beyond the Standard Model at the energy scales accessible to experiments at the
Tevatron and the LHC, focusing on their experimental signatures.


title: Geometric structure of NLS evolution

abstract:
  We clarify the relation between the Hamiltonian and Lagrangian approaches to
nonlinear evolution equations, focusing specifically on the nonlinear
Schroedinger equation. In particular, we explain the least action principle and
the Noether theorem in this context.


title:
Schroedinger Operators on Regular Metric Trees with Long Range
  Potentials: Weak Coupling Behavior

abstract:
  Consider a regular $d$-dimensional metric tree $\Gamma$ with root $o$. Define
the Schroedinger operator $-\Delta - V$, where $V$ is a non-negative, symmetric
potential, on $\Gamma$, with Neumann boundary conditions at $o$. Provided that
$V$ decays like $x^{-\gamma}$ at infinity, where $1 < \gamma \leq d \leq 2,
\gamma \neq 2$, we will determine the weak coupling behavior of the bottom of
the spectrum of $-\Delta - V$. In other words, we will describe the
asymptotical behavior of $\inf \sigma(-\Delta - \alpha V)$ as $\alpha \to 0+$


title: A Removal Lemma for Systems of Linear Equations over Finite Fields

abstract:
  We prove a removal lemma for systems of linear equations over finite fields:
let $X_1,...,X_m$ be subsets of the finite field $\F_q$ and let $A$ be a
$(k\times m)$ matrix with coefficients in $\F_q$ and rank $k$; if the linear
system $Ax=b$ has $o(q^{m-k})$ solutions with $x_i\in X_i$, then we can destroy
all these solutions by deleting $o(q)$ elements from each $X_i$. This extends a
result of Green [Geometric and Functional Analysis 15(2) (2005), 340--376] for
a single linear equation in abelian groups to systems of linear equations. In
particular, we also obtain an analogous result for systems of equations over
integers, a result conjectured by Green. Our proof uses the colored version of
the hypergraph Removal Lemma.


title: Some remarks on bounded earthquakes

abstract:
  We first show that an earthquake of a geometrically infinite hyperbolic
surface induces an asymptotically conformal change in the hyperbolic metric if
and only if the measured lamination associated with the earthquake is
asymptotically trivial on the surface. Then we show that the contraction along
earthquake paths is continuous in the Teichm\"uller space of any hyperbolic
surface. Finally, we show that if a measured lamination vanishes while
approaching infinity at the rate higher than the distance to the boundary then
it must be trivial.


title: The distribution of the zeroes of random trigonometric polynomials

abstract:
  We study the asymptotic distribution of the number $Z_{N}$ of zeros of random
trigonometric polynomials of degree $N$ as $N\to\infty$. It is known that as
$N$ grows to infinity, the expected number of the zeros is asymptotic to
$\frac{2}{\sqrt{3}}\cdot N$. The asymptotic form of the variance was predicted
by Bogomolny, Bohigas and Leboeuf to be $cN$ for some $c>0$. We prove that
$\frac{Z_{N}-\E Z_{N}}{\sqrt{cN}}$ converges to the standard Gaussian. In
addition, we find that the analogous result is applicable for the number of
zeros in short intervals.


title: How to verify the redshift mechanism of low-energy quantum gravity

abstract:
  In the model of low-energy quantum gravity by the author, the redshift
mechanism is quantum and local, and it is not connected with any expansion of
the Universe. A few possibilities to verify its predictions are considered
here: the specialized ground-based laser experiment; a deceleration of massive
bodies and the Pioneer anomaly; a non-universal character of the Hubble diagram
for soft and hard radiations; galaxy/quasar number counts.


title: Optimized Multiple Quantum MAS Lineshape Simulations in Solid State NMR

abstract:
  The majority of nuclei available for study in solid state Nuclear Magnetic
Resonance have half-integer spin $I > 1/2 $, with corresponding electric
quadrupole moment. As such, they may couple with a surrounding electric field
gradient. This effect introduces anisotropic line broadening to spectra,
arising from distinct chemical species within polycrystalline solids. In
Multiple Quantum Magic Angle Spinning (MQMAS) experiments, a second frequency
dimension is created, devoid of quadrupolar anisotropy. As a result, the center
of gravity of peaks in the high resolution dimension is a function of isotropic
second order quadrupole and chemical shift alone. However, for complex
materials, these parameters take on a stochastic nature due in turn to
structural and chemical disorder. Lineshapes may still overlap in the isotropic
dimension, complicating the task of assignment and interpretation. A
distributed computational approach is presented here which permits simulation
of the two-dimensional MQMAS spectrum, generated by random variates from model
distributions of isotropic chemical and quadrupole shifts. Owing to the
non-convex nature of the residual sum of squares (RSS) function between
experimental and simulated spectra, simulated annealing is used to optimize the
simulation parameters. In this manner, local chemical environments for
disordered materials may be characterized, and via a re-sampling approach,
error estimates for parameters produced.


title: Quantum Density Fluctuations in Classical Liquids

abstract:
  We discuss the density fluctuations of a fluid due to zero point motion.
These can be regarded as density fluctuations in the phonon vacuum state. We
assume a linear dispersion relation with a fixed speed of sound and calculate
the density correlation function. We note that this function has the same form
as the correlation function for the time derivative of a relativistic massless
scalar field, but with the speed of light replaced by the speed of sound. As a
result, the study of density fluctuations in a fluid can be a useful analog
model for better understanding fluctuations in relativistic quantum field
theory. We next calculate the differential cross section for light scattering
by the zero point density fluctuations, and find a result proportional to the
fifth power of the light frequency. This can be understood as the product of
fourth power dependence of the usual Rayleigh cross section with the linear
frequency dependence of the spectrum of zero point density fluctuations. We
give some estimates of the relative magnitude of this effect compared to the
scattering by thermal density fluctuations, and find that it can be of order
0.5% for water at room temperature and optical frequencies. This relative
magnitude is proportional to frequency and inversely proportional to
temperature. Although the scattering by zero point density fluctuation is
small, it may be observable.


title:
Picovoltmeter for probing vortex dynamics in a single weak-pinning
  Corbino channel

abstract:
  We have developed a picovoltmeter using a Nb dc Superconducting QUantum
Interference Device (SQUID) for measuring the flux-flow voltage from a small
number of vortices moving through a submicron weak-pinning superconducting
channel. We have applied this picovoltmeter to measure the vortex response in a
single channel arranged in a circle on a Corbino disk geometry. The circular
channel allows the vortices to follow closed orbits without encountering any
sample edges, thus eliminating the influence of entry barriers.


title: The minimal degree of plane models of double covers of smooth curves

abstract:
  If $X$ is a smooth curve such that the minimal degree of its plane models is
not too small compared with its genus, then $X$ has been known to be a double
cover of another smooth curve $Y$ under some mild condition on the genera.
However there are no results yet for the minimal degrees of plane models of
double covers except some special cases. In this paper, we give upper and lower
bounds for the minimal degree of plane models of the double cover $X$ in terms
of the gonality of the base curve $Y$ and the genera of $X$ and $Y$. In
particular, the upper bound equals to the lower bound in case $Y$ is
hyperelliptic. We give an example of a double cover which has plane models of
degree equal to the lower bound.


title: Divisor Problem and an Analogue of Euler's Summation Formula

abstract:
  By simple elementary method,we obtain with ease,a highly simple expression
for the remainder term of the divisor problem and use it to obtain an
Euler-Maclaurin analogue of summation involving divisor function.We also obtain
a relation connecting the remainder term of the divisor problem and the
remainders of approximate functional equations for Riemann zeta function and
its square,for positive values of arguments.


title: Planetary Transits and Tidal Evolution

abstract:
  Transiting planets are generally close enough to their host stars that tides
may govern their orbital and thermal evolution of these planets. We present
calculations of the tidal evolution of recently discovered transiting planets
and discuss their implications. The tidal heating that accompanies this orbital
evolution can be so great that it controls the planet's physical properties and
may explain the large radii observed in several cases, including, for example,
TrES-4. Also because a planet's transit probability depends on its orbit, it
evolves due to tides. Current values depend sensitively on the physical
properties of the star and planet, as well as on the system's age. As a result,
tidal effects may introduce observational biases in transit surveys, which may
already be evident in current observations. Transiting planets tend to be
younger than non-transiting planets, an indication that tidal evolution may
have destroyed many close-in planets. Also the distribution of the masses of
transiting planets may constrain the orbital inclinations of non-transiting
planets.


title: The distribution of Pearson residuals in generalized linear models

abstract:
  In general, the distribution of residuals cannot be obtained explicitly. We
give an asymptotic formula for the density of Pearson residuals in continuous
generalized linear models corrected to order $n^{-1}$, where $n$ is the sample
size. We define corrected Pearson residuals for these models that, to this
order of approximation, have exactly the same distribution of the true Pearson
residuals. Applications for important generalized linear models are provided
and simulation results for a gamma model illustrate the usefulness of the
corrected Pearson residuals.


title: Entanglement of Solitons in the Frenkel-Kontorova Model

abstract:
  We investigate entanglement of solitons in the continuum-limit of the
nonlinear Frenkel-Kontorova chain. We find that the entanglement of solitons
manifests particle-like behavior as they are characterized by localization of
entanglement. The von-Neumann entropy of solitons mixes critical with
noncritical behaviors. Inside the core of the soliton the logarithmic increase
of the entropy is faster than the universal increase of a critical field,
whereas outside the core the entropy decreases and saturates the constant value
of the corresponding massive noncritical field. In addition, two solitons
manifest long-range entanglement that decreases with the separation of the
solitons more slowly than the universal decrease of the critical field.
Interestingly, in the noncritical regime of the Frenkel-Kontorova model,
entanglement can even increase with the separation of the solitons. We show
that most of the entanglement of the so-called internal modes of the solitons
is saturated by local degrees of freedom inside the core, and therefore we
suggest using the internal modes as carriers of quantum information.


title:
Minimum-Free-Energy Distribution of RNA Secondary Structures: Entropic
  and Thermodynamic Properties of Rare Events

abstract:
  We study the distribution of the minimum free energy (MFE) for the Turner
model of pseudoknot free RNA secondary structures over ensembles of random RNA
sequences. In particular, we are interested in those rare and intermediate
events of unexpected low MFEs. Generalized ensemble Markov-chain Monte Carlo
methods allow us to explore the rare-event tail of the MFE distribution down to
probabilities like $10^{-70}$ and to study the relationship between the
sequence entropy and structural properties for sequence ensembles with fixed
MFEs. Entropic and structural properties of those ensembles are compared with
natural RNA of the same reduced MFE (z-score).


title: Quintessential Kination and Thermal Production of Gravitinos and Axinos

abstract:
  The impact of a kination-dominated phase generated by a quintessential
exponential model on the thermal abundance of gravitinos and axinos is
investigated. We find that their abundances become proportional to the
transition temperature from the kination to the radiation era; since this
temperature is significantly lower than the initial ("reheating") temperature,
the abundances decrease with respect to their values in the standard cosmology.
For values of the quintessential energy-density parameter close to its upper
bound, at the eve of nucleosynthesis, we find the following: (i) for unstable
gravitinos, the gravitino constraint is totally evaded; (ii) If the gravitino
is stable, its thermal abundance is not sufficient to account for the cold dark
matter of the universe; (iii) the thermal abundance of axinos can satisfy the
cold dark matter constraint for values of the initial temperature well above
those required in the standard cosmology. A novel calculation of the axino
production rate by scatterings at low temperature is also presented.


title: Explicit expressions for moments of the beta Weibull distribution

abstract:
  The beta Weibull distribution was introduced by Famoye et al. (2005) and
studied by these authors. However, they do not give explicit expressions for
the moments. We now derive explicit closed form expressions for the cumulative
distribution function and for the moments of this distribution. We also give an
asymptotic expansion for the moment generating function. Further, we discuss
maximum likelihood estimation and provide formulae for the elements of the
Fisher information matrix. We also demonstrate the usefulness of this
distribution on a real data set.


title:
Influence of the atomic-scale inhomogeneity of the pair interaction on
  extracted from the STM spectra characteristics of high-$T_c$ superconductors

abstract:
  The influence of the atomic-scale inhomogeneities of the pairing interaction
strength on the superconducting order parameter and the conductance spectra
measurable by STM is studied in the framework of weak-coupling BCS-like theory
for two-dimensional lattice model. First of all, it is found that the
inhomogeneity having the form of atomic-scale regions of enhanced pair
interaction increases the ratio of the local low-temperature gap in
differential conductance spectra to the local temperature of vanishing the gap
$2\Delta_g/T_p$. Even in the framework of mean-field treatment this ratio is
shown to be larger than the one corresponding to the homogeneous case. It is
shown that the effect of thermal phase fluctuations of the superconducting
order parameter can further increase this ratio. Taking them into account in
the framework of a toy model we obtained the ratio $2\Delta_g/T_p$ to be $\sim
7-8$. It is found that the additional atomic-scale hopping element disorder and
weak potential scatterers, which can also take place in cuprate materials, have
no considerable effect on the statistical properties of the system, including
the distribution of the gaps, $T_p$ and the ratio $2\Delta_g/T_p$. The second
consequence of the atomic-scale order parameter inhomogeneity is the
anticorrelation between the low-temperature gap and the high-temperature
zero-bias conductance. The obtained results could bear a relation to recent STM
measurements.


title: Luminescence Properties of a Fibonacci Photonic Quasicrystal

abstract:
  We report the realization of an active one-dimensional Fibonacci photonic
quasi-crystal via spin coating. Manipulation of the luminescence properties of
an organic dye embedded in the quasi-crystal is presented and compared to
theoretical simulations. The luminescence occurs via the pseudo-bandedge mode
and follows the dispersion properties of the Fibonacci crystal. Time resolved
luminescence measurement of the active structure shows faster spontaneous
emission rate, indicating the effect of the large photon densities available at
the bandedge due to the presence of critically localized states. The
experimental results are in excellent agreement with the theoretical
calculations.


title:
Vector Meson Dominance as the first order of a sequence of Pade
  Approximants

abstract:
  The use of Pade Approximants for the analysis of the pion vector form-factor
is discussed and justified in this talk. The method is tested first in a
theoretical model and applied then on real experimental data. It is shown how
the Pade Approximants provide a convenient and reliable framework to
incorporate both low and high energy information in the euclidean region,
leading to improved determinations of the low energy parameters such as, e.g.,
the quadratic radius <r^2>^pi_V.


title:
On the invariant measure of the random difference equation $X_n=A_n
  X_{n-1}+ B_n$ in the critical case

abstract:
  We consider the autoregressive model on $\R^d$ defined by the following
stochastic recursion $X_n = A_n X_{n-1}+B_n$, where $\{(B_n,A_n)\}$ are i.i.d.
random variables valued in $\R^d\times \R^+$. The critical case, when
$\E\big[\log A_1\big]=0$, was studied by Babillot, Bougeorol and Elie, who
proved that there exists a unique invariant Radon measure $\nu$ for the Markov
chain $\{X_n \}$. In the present paper we prove that the weak limit of properly
dilated measure $\nu$ exists and defines a homogeneous measure on
$\R^d\setminus \{0\}$.


title:
TiO and VO broad band absorption features in the optical spectrum of the
  atmosphere of the hot-Jupiter HD209458b

abstract:
  The presence of titanium oxide (TiO) and vanadium oxide (VO) gas phase
species is searched for in the atmosphere of the hot Jupiter HD209458b. We
compared a model for the planets transmitted spectrum to multi-wavelength
eclipse-depth measurements (from 3000 to 10000 Angstrom), obtained by Sing et
al. (2008a) using archived HST-STIS time series spectra. We make use of these
observations to search for spectral signatures from extra absorbers in the
planet atmosphere between 6000 and 8000 Angstrom. Along with sodium depletion
and Rayleigh scattering recently published for this exoplanet atmosphere, an
extra absorber of uncertain origin, redward of the sodium lines, resides in the
atmosphere of the planet. Furthermore, this planet has a stratosphere
experiencing a thermal inversion caused by the capture of optical stellar flux
by absorbers that resides at altitude. Recent models have predicted that the
presence of TiO and VO in the atmosphere of HD209458b may be responsible for
this temperature inversion. Although no specific TiO and VO spectral band head
signatures have been identified unambiguously in the observed spectrum, we
suggest here that the opacities of those molecules are possible candidates to
explain the remaining continuous broad band absorption observed between 6200
and 8000 Angstrom. To match reasonably well the data, the abundances of TiO and
VO molecules are evaluated from ten to one thousand times below solar. This
upper limit result is in agreement with expected variations with altitude due
to depletion effects such as condensation.


title: Frame-dragging and the kinematics of Galactic-Center stars

abstract:
  We calculate the effects of frame dragging on the Galactic-Center stars.
Assuming the stars are only slightly relativistic, we derive an approximation
to the Kerr metric, which turns out to be a weak field Schwarzschild metric
plus a frame dragging term. By numerically integrating the resulting geodesic
equations, we compute the effect on keplerian elements and the kinematics. We
find that the kinematic effect at pericenter passage is proportional to
(a(1-e^2))^{-2}. For known Galactic-center stars it is of order 10 m/s. If
observed this would provide a measurement of the spin of the black hole.


title:
Modeling the color evolution of luminous red galaxies - improvements
  with empirical stellar spectra

abstract:
  Predicting the colors of Luminous Red Galaxies (LRGs) in the Sloan Digital
Sky Survey (SDSS) has been a long-standing problem. The g,r,i colors of LRGs
are inconsistent with stellar population models over the redshift range
0.1<z<0.7. The g-r colors in the models are on average redder than the data
while the r-i colors in the models are bluer towards low redshift. Beyond
redshift 0.4, the predicted r-i color becomes instead too red, while the
predicted g-r agrees with the data. We provide a solution to this problem,
through a combination of new astrophysics and a fundamental change to the
stellar population modeling. We find that the use of the empirical library of
Pickles (1998) instead of theoretical spectra modifies the predicted colors
exactly in the way suggested by the data. The reason is a lower flux in the
empirical libraries, with respect to the theoretical ones, in the wavelength
range 5500-6500 AA. The discrepancy increases with decreasing effective
temperature independently of gravity. This result has general implications for
a variety of studies from globular clusters to high-redshift galaxies. The
astrophysical part of our solution regards the composition of the stellar
populations of these massive Luminous Red Galaxies. We find that on top of the
previous effect one needs to consider a model in which ~3% of the stellar mass
is in old metal-poor stars. Other solutions such as substantial blue Horizontal
Branch at high metallicity or young stellar populations can be ruled out by the
data. Our new model provides a better fit to the g-r and r-i colors of LRGs and
gives new insight into the formation histories of these most massive galaxies.
Our model will also improve the k- and evolutionary corrections for LRGs which
are critical for fully exploiting present and future galaxy surveys.


title:
Halo Occupation Distribution Modeling of Clustering of Luminous Red
  Galaxies

abstract:
  We perform Halo Occupation Distribution (HOD) modeling to interpret
small-scale and intermediate-scale clustering of 35,000 luminous early-type
galaxies and their cross-correlation with a reference imaging sample of normal
L* galaxies in the Sloan Digital Sky Survey. The modeling results show that
most of these luminous red galaxies (LRGs) are central galaxies residing in
massive halos of typical mass M ~ a few times 10^13 to 10^14 Msun/h, while a
few percent of them have to be satellites within halos in order to produce the
strong auto-correlations exhibited on smaller scales. The mean luminosity Lc of
central LRGs increases with the host halo mass, with a rough scaling relation
of Lc \propto M^0.5. The halo mass required to host on average one satellite
LRG above a luminosity threshold is found to be about 10 times higher than that
required to host a central LRG above the same threshold. We find that in
massive halos the distribution of L* galaxies roughly follows that of the dark
matter and their mean occupation number scales with halo mass as M^1.5. The HOD
modeling results also allows for an intuitive understanding of the
scale-dependent luminosity dependence of the cross-correlation between LRGs and
L_* galaxies. Constraints on the LRG HOD provide tests to models of formation
and evolution of massive galaxies, and they are also useful for cosmological
parameter investigations. In one of the appendices, we provide LRG HOD
parameters with dependence on cosmology inferred from modeling the two-point
auto-correlation functions of LRGs.


title: Physics at BES-III

abstract:
  This physics book provides detailed discussions on important topics in
$\tau$-charm physics that will be explored during the next few years at \bes3 .
Both theoretical and experimental issues are covered, including extensive
reviews of recent theoretical developments and experimental techniques. Among
the subjects covered are: innovations in Partial Wave Analysis (PWA),
theoretical and experimental techniques for Dalitz-plot analyses, analysis
tools to extract absolute branching fractions and measurements of decay
constants, form factors, and CP-violation and \DzDzb-oscillation parameters.
Programs of QCD studies and near-threshold tau-lepton physics measurements are
also discussed.


title: SAtlas: Spherical Versions of the Atlas Stellar Atmosphere Program

abstract:
  Context: The current stellar atmosphere programs still cannot match some
fundamental observations of the brightest stars, and with new techniques, such
as optical interferometry, providing new data for these stars, additional
development of stellar atmosphere codes is required. Aims: To modify the
open-source model atmosphere program Atlas to treat spherical geometry,
creating a test-bed stellar atmosphere code for stars with extended
atmospheres. Methods: The plane-parallel Atlas has been changed by introducing
the necessary spherical modifications in the pressure structure, in the
radiative transfer and in the temperature correction. Results: Several test
models show that the spherical program matches the plane-parallel models in the
high surface gravity regime, and matches spherical models computed by Phoenix
and by MARCS in the low gravity case.


title: Dark stars at the Galactic centre - the main sequence

abstract:
  In regions of very high dark matter density such as the Galactic centre, the
capture and annihilation of WIMP dark matter by stars has the potential to
significantly alter their evolution. We describe the dark stellar evolution
code DarkStars, and present a series of grids of WIMP-influenced stellar models
for main sequence stars. We describe changes in which occur as a function of
the rate of energy injection by WIMPs, for stars of 0.3-2.0 solar masses and
metallicities Z = 0.0003-0.02. We show what rates of energy injection can be
obtained using realistic orbital parameters for stars at the Galactic centre,
including detailed consideration of the velocity and density profiles of dark
matter. Capture and annihilation rates are strongly boosted when stars follow
elliptical rather than circular orbits. If there is a spike of dark matter
induced by the supermassive black hole at the Galactic centre, single
solar-mass stars following orbits with periods as long as 50 years and
eccentricities as low as 0.9 could be significantly affected. Binary systems
with similar periods about the Galactic centre could be affected on even less
eccentric orbits. The most striking evidence of this scenario would be the
existence of a binary consisting of a low-mass protostar and a higher-mass
evolved star. The observation of low-mass stars and/or binaries on such orbits
would either provide a detection of WIMP dark matter, or place stringent limits
on the combination of the WIMP mass, spin-dependent nuclear-scattering
cross-section, halo density and velocity distribution near the Galactic centre.
In some cases, the limits on the WIMP mass and spin-dependent
nuclear-scattering cross-section would be of comparable sensitivity to current
direct-detection experiments.


title: Covering by discrete and closed discrete sets

abstract:
  Say that a cardinal number $\kappa$ is \emph{small} relative to the space $X$
if $\kappa <\Delta(X)$, where $\Delta(X)$ is the least cardinality of a
non-empty open set in $X$. We prove that no Baire metric space can be covered
by a small number of discrete sets, and give some generalizations. We show a
ZFC example of a regular Baire $\sigma$-space and a consistent example of a
normal Baire Moore space which can be covered by a small number of discrete
sets. We finish with some remarks on linearly ordered spaces.


title: Some results for beta Fr\'echet distribution

abstract:
  Nadarajah and Gupta (2004) introduced the beta Fr\'echet (BF) distribution,
which is a generalization of the exponentiated Fr\'echet (EF) and Fr\'echet
distributions, and obtained the probability density and cumulative distribution
functions. However, they do not investigated its moments and the order
statistics. In this paper the BF density function and the density function of
the order statistics are expressed as linear combinations of Fr\'echet density
functions. This is important to obtain some mathematical properties of the BF
distribution in terms of the corresponding properties of the Fr\'echet
distribution. We derive explicit expansions for the ordinary moments and
L-moments and obtain the order statistics and their moments. We also discuss
maximum likelihood estimation and calculate the information matrix which was
not known. The information matrix is easily numerically determined. Two
applications to real data sets are given to illustrate the potentiality of this
distribution.


title: Closing in on the sources of Galactic and extragalactic cosmic rays

abstract:
  We speculate that a new generation of particle astrophysics instrumentation
will reveal the enigmatic sources of cosmic rays prior to the one hundredth
anniversary of their discovery by Hess in 1912. While only a "smoking gun'' is
missing for the case that the galactic component of the cosmic ray spectrum
originates in supernova remnants, deciphering the origin of the extragalactic
component is still at a level of reading tea leaves.


title:
Determining Parameters of Cool Giant Stars by Modeling
  Spectrophotometric and Interferometric Observations Using the SAtlas Program

abstract:
  Context: Optical interferometry is a powerful tool for observing the
intensity structure and angular diameter of stars. When combined with
spectroscopy and/or spectrophotometry, interferometry provides a powerful
constraint for model stellar atmospheres. Aims: The purpose of this work is to
test the robustness of the spherically symmetric version of the Atlas stellar
atmosphere program, SAtlas, using interferometric and spectrophotometric
observations. Methods: Cubes (three dimensional grids) of model stellar
atmospheres, with dimensions of luminosity, mass, and radius, are computed to
fit observations for three evolved giant stars, \psi Phoenicis, \gamma
Sagittae, and \alpha Ceti. The best-fit parameters are compared with previous
results. Results: The best-fit angular diameters and values of \chi^2 are
consistent with predictions using Phoenix and plane-parallel Atlas models. The
predicted effective temperatures, using SAtlas, are about 100 to 200 K lower,
and the predicted luminosities are also lower due to the differences in
effective temperatures. Conclusions: It is shown that the SAtlas program is a
robust tool for computing models of extended stellar atmospheres that are
consistent with observations. The best-fit parameters are consistent with
predictions using Phoenix models, and the fit to the interferometric data for
\psi Phe differs slightly, although both agree within the uncertainty of the
interferometric observations.


title: Gravity Dual of a Quantum Hall Plateau Transition

abstract:
  We show how to model the transition between distinct quantum Hall plateaus in
terms of D-branes in string theory. A low energy theory of 2+1 dimensional
fermions is obtained by considering the D3-D7 system, and the plateau
transition corresponds to moving the branes through one another. We study the
transition at strong coupling using gauge/gravity duality and the probe
approximation. Strong coupling leads to a novel kind of plateau transition: at
low temperatures the transition remains discontinuous due to the effects of
dynamical symmetry breaking and mass generation, and at high temperatures is
only partially smoothed out.


title: Negative Energies and Field Theory

abstract:
  The assumption that the vacuum is the minimum energy state, invariant under
unitary transformations, is fundamental to quantum field theory. However, the
assertion that the conservation of charge implies that the equal time
commutator of the charge density and its time derivative vanish for two
spatially separated points is inconsistent with the requirement that the vacuum
be the lowest energy state. Yet, for quantum field theory to be gauge
invariant, this commutator must vanish. This essay explores how this conundrum
is resolved in quantum electrodynamics.


title: Improved estimators for a general class of beta regression models

abstract:
  In this paper we consider an extension of the beta regression model proposed
by Ferrari and Cribari-Neto (2004). We extend their model in two different
ways, first, we let the regression structure be nonlinear, second, we allow a
regression structure for the precision parameter, moreover, this regression
structure may also be nonlinear. Generally, the beta regression is useful to
situations where the response is restricted to the standard unit interval and
the regression structure involves regressors and unknown parameters. We derive
general formulae for second-order biases of the maximum likelihood estimators
and use them to define bias-corrected estimators. Our formulae generalizes the
results obtained by Ospina et al. (2006), and are easily implemented by means
of supplementary weighted linear regressions. We also compare these
bias-corrected estimators with three different estimators which are also
bias-free to the second-order, one analytical and the other two based on
bootstrap methods. These estimators are compared by simulation. We present an
empirical application.


title: Algebraic structures on the topology of moduli spaces of curves and maps

abstract:
  We discuss selected topics on the topology of moduli spaces of curves and
maps, emphasizing their relation with Gromov--Witten theory and integrable
systems.


title: Gauged supersymmetries in Yang-Mills theory

abstract:
  In this paper we show that Yang-Mills theory in the
Curci-Ferrari-Delbourgo-Jarvis gauge admits some up to now unknown local linear
Ward identities. These identities imply some non-renormalization theorems with
practical simplifications for perturbation theory. We show in particular that
all renormalization factors can be extracted from two-point functions. The Ward
identities are shown to be related to supergauge transformations in the
superfield formalism for Yang-Mills theory. The case of non-zero Curci-Ferrari
mass is also addressed.


title:
An Upper Mass Limit on a Red Supergiant Progenitor for the Type
  II-Plateau Supernova SN 2006my

abstract:
  We analyze two pre-supernova (SN) and three post-SN high-resolution images of
the site of the Type II-Plateau supernova SN 2006my in an effort to either
detect the progenitor star or to constrain its properties. Following image
registration, we find that an isolated stellar object is not detected at the
location of SN 2006my in either of the two pre-SN images. In the first, an
I-band image obtained with the Wide-Field and Planetary Camera 2 on board the
Hubble Space Telescope, the offset between the SN 2006my location and a
detected source ("Source 1") is too large: > 0.08", which corresponds to a
confidence level of non-association of 96% from our most liberal estimates of
the transformation and measurement uncertainties. In the second, a similarly
obtained V-band image, a source is detected ("Source 2") that has overlap with
the SN 2006my location but is definitively an extended object. Through
artificial star tests carried out on the precise location of SN 2006my in the
images, we derive a 3-sigma upper bound on the luminosity of a red supergiant
that could have remained undetected in our pre-SN images of log L/L_Sun = 5.10,
which translates to an upper bound on such a star's initial mass of 15 M_Sun
from the STARS stellar evolutionary models. Although considered unlikely, we
can not rule out the possibility that part of the light comprising Source 1,
which exhibits a slight extension relative to other point sources in the image,
or part of the light contributing to the extended Source 2, may be due to the
progenitor of SN 2006my. Only additional, high-resolution observations of the
site taken after SN 2006my has faded beyond detection can confirm or reject
these possibilities.


title: Modelling clusters of galaxies by f(R)-gravity

abstract:
  We consider the possibility that masses and gravitational potentials of
galaxy cluster, estimated at X-ray wavelengths, could be explained without
assuming huge amounts of dark matter, but in the context of $f(R)$-gravity.
Specifically, we take into account the weak field limit of such theories and
show that the corrected gravitational potential allows to estimate the total
mass of a sample of 12 clusters of galaxies. Results show that such a
gravitational potential provides a fair fit to the mass of visible matter (i.e.
gas + stars) estimated by X-ray observations, without the need of additional
dark matter while the size of the clusters, as already observed at different
scale for galaxies, strictly depends on the interaction lengths of the
corrections to the Newtonian potential.


title: Dissecting brick into bars

abstract:
  An $N$-dimensional parallelepiped will be called a bar if and only if there
are no more than $k$ different numbers among the lengths of its sides (the
definition of bar depends on $k$). We prove that a parallelepiped can be
dissected into finite number of bars iff the lengths of sides of the
parallelepiped span a linear space of dimension no more than $k$ over $\QQ$.
This extends and generalizes a well-known theorem of Max Dehn about partition
of rectangles into squares. Several other results about dissections of
parallelepipeds are obtained.


title:
Investigating the high energy QCD approaches for prompt photon
  production at the LHC

abstract:
  We investigate the rapidity and transverse momentum distributions of the
prompt photon production at the CERN LHC energies considering the current
perturbative QCD approaches for this scattering process. Namely, we compare the
predictions from the usual NLO pQCD calculations to the the color dipole
formalism, using distinct dipole cross sections. Special attention is paid to
parton saturation models at high energies, which are expected to be important
at the forward rapidities in pp collisions at the LHC.


title: Purity at the end

abstract:
  We consider smooth completion of algebraic manifolds. Having some information
about its singular completions or about completions of its images we prove
purity of cohohomology of the set at infinity. We deduce also some topological
properties. The work is based on the study of perverse direct images for
algebraic maps.


title:
Volume Effects for Pion Two-Point Functions in Constant Electric and
  Magnetic Fields

abstract:
  We compute finite volume effects relevant for lattice QCD simulations using
background fields. Focusing on constant electric and magnetic fields on a
periodic lattice, we determine volume corrections to pion two-point functions
using chiral perturbation theory. Among such corrections are the finite volume
shifts to the electric and magnetic polarizabilities, which are numerically
shown to be non-negligible. We additionally find that all terms in the
single-particle effective action can be renormalized by infrared effects. This
includes Born couplings to the pion current and total charge-squared, which can
be renormalized due to the nature of gauge invariance on a torus.


title:
Detector Backaction on the Self-Consistent Bound State in Quantum Point
  Contacts

abstract:
  Bound-state (BS) formation in quantum point contacts (QPCs) may offer a
convenient way to localize and probe single spins. In this letter, we
investigate how such BSs are affected by monitoring them with a second QPC,
which is coupled to the BS via wavefunction overlap. We show that this coupling
leads to a unique detector backaction, in which the BS is weakened by
increasing its proximity to the detector. We also show, however, that this
interaction between the QPCs can be regulated at will, by using an additional
gate to control their wavefunction overlap.


title: Special relativity may account for the spacecraft flyby anomalies

abstract:
  The empirical formula proposed by J. D. Anderson et al. [1] to reproduce the
data on the Earth flyby anomalies is derived from special relativity (SR). The
transverse Doppler shift together with the addition of velocities account for
the Doppler data. Time dilation together with the addition of velocities
account for the ranging data.


title: The Beta Generalized Exponential Distribution

abstract:
  We introduce the beta generalized exponential distribution that includes the
beta exponential and generalized exponential distributions as special cases. We
provide a comprehensive mathematical treatment of this distribution. We derive
the moment generating function and the $r$th moment thus generalizing some
results in the literature. Expressions for the density, moment generating
function and $r$th moment of the order statistics also are obtained. We discuss
estimation of the parameters by maximum likelihood and provide the information
matrix. We observe in one application to real data set that this model is quite
flexible and can be used quite effectively in analyzing positive data in place
of the beta exponential and generalized exponential distributions.


title:
Population boundaries for compact white-dwarf binaries in LISA's
  amplitude-frequency domain

abstract:
  In an earlier investigation, we proposed population boundaries for both
inspiralling and mass-transferring double white dwarf (DWD) systems in the
distance independent "absolute" amplitude-frequency domain of the proposed
space-based gravitational-wave (GW) detector, {\it LISA}. The degenerate zero
temperature mass-radius (M-R) relationship of individual white dwarf stars that
we assumed, in combination with the constraints imposed by Roche geometries,
permits us to identify five key population boundaries for DWD systems in
various phases of evolution. Here we use the non-zero entropy donor M-R
relations of \cite{DB2003} to modify these boundaries for both DWD and neutron
star-white dwarf (NSWD) binary systems. We find that the mass-transferring
systems occupy a larger fraction of space in ``absolute'' amplitude-frequency
domain compared to the simpler T=0 donor model. We also discuss how these
boundaries are modified with the new evolutionary phases found by
\cite{Deloyeetal2007}. In the initial contact phase, we find that the contact
boundaries, which are the result of end of inspiral evolution, would have some
width, as opposed to an abrupt cut-off described in our earlier T=0 model. This
will cause an overlap between a DWDs $&$ NSWDs evolutionary trajectories,
making them indistinguishable with only LISA observations within this region.
In the cooling phase of the donor, which follows after the adiabatic donor
evolution, the radius contracts, mass-transfer rate drops and slows down the
orbital period evolution. Depending upon the entropy of the donor, these
systems may then lie inside the fully degenerate T=0 boundaries, but LISA may
be unable to detect these systems as they might be below the sensitivity limit
or within the unresolved DWD background noise.


title: When is tight closure determined by the test ideal?

abstract:
  We characterize the rings in which the equality $(\tau I:\tau)= I^*$ holds
for every ideal $I \subset R$. Under certain assumptions, these rings must be
either weakly F-regular or one-dimensional.


title: Universal Properties of the Ultra-Cold Fermi Gas

abstract:
  We present some general considerations on the properties of a two-component
ultra-cold Fermi gas along the BEC-BCS crossover. It is shown that the
interaction energy and the ground state energy can be written in terms of a
single dimensionless function $h({\xi,\tau})$, where $\xi=-(k_Fa_s)^{-1}$ and
$\tau=T/T_F$. The function $h(\xi,\tau)$ incorporates all the many-body physics
and naturally occurs in other physical quantities as well. In particular, we
show that the RF-spectroscopy shift $\bar{\d\o}(\xi,\tau)$ and the molecular
fraction $f_c(\xi,\tau)$ in the closed channel can be expressed in terms of
$h(\xi,\tau)$ and thus have identical temperature dependence. The conclusions
should have testable consequences in future experiments.


title:
Kramers degeneracy in a magnetic field and Zeeman spin-orbit coupling in
  antiferromagnets

abstract:
  In this article, I analyze the symmetries and degeneracies of electron
eigenstates in a commensurate collinear antiferromagnet. In a magnetic field
transverse to the staggered magnetization, a hidden anti-unitary symmetry
protects double degeneracy of the Bloch eigenstates at a special set of
momenta. In addition to this `Kramers degeneracy' subset, the manifold of
momenta, labeling the doubly degenerate Bloch states in the Brillouin zone, may
also contain an `accidental degeneracy' subset, that is not protected by
symmetry and that may change its shape under perturbation. These degeneracies
give rise to a substantial momentum dependence of the transverse g-factor in
the Zeeman coupling, turning the latter into a spin-orbit interaction.
  I discuss a number of materials, where Zeeman spin-orbit coupling is likely
to be present, and outline the simplest properties and experimental
consequences of this interaction, that may be relevant to systems from chromium
to borocarbides, cuprates, hexaborides, iron pnictides, as well as organic and
heavy fermion conductors.


title: A Generalization of the Exponential-Poisson Distribution

abstract:
  The two-parameter distribution known as exponential-Poisson (EP)
distribution, which has decreasing failure rate, was introduced by Kus (2007).
In this paper we generalize the EP distribution and show that the failure rate
of the new distribution can be decreasing or increasing. The failure rate can
also be upside-down bathtub shaped. A comprehensive mathematical treatment of
the new distribution is provided. We provide closed-form expressions for the
density, cumulative distribution, survival and failure rate functions; we also
obtain the density of the $i$th order statistic. We derive the $r$th raw moment
of the new distribution and also the moments of order statistics. Moreover, we
discuss estimation by maximum likelihood and obtain an expression for Fisher's
information matrix. Furthermore, expressions for the R\'enyi and Shannon
entropies are given and estimation of the stress-strength parameter is
discussed. Applications using two real data sets are presented.


title: Thinking Twice about Second-Price Ad Auctions

abstract:
  Recent work has addressed the algorithmic problem of allocating advertisement
space for keywords in sponsored search auctions so as to maximize revenue, most
of which assume that pricing is done via a first-price auction. This does not
realistically model the Generalized Second Price (GSP) auction used in
practice, in which bidders pay the next-highest bid for keywords that they are
allocated. Towards the goal of more realistically modeling these auctions, we
introduce the Second-Price Ad Auctions problem, in which bidders' payments are
determined by the GSP mechanism. We show that the complexity of the
Second-Price Ad Auctions problem is quite different than that of the more
studied First-Price Ad Auctions problem. First, unlike the first-price variant,
for which small constant-factor approximations are known, it is NP-hard to
approximate the Second-Price Ad Auctions problem to any non-trivial factor,
even when the bids are small compared to the budgets. Second, this discrepancy
extends even to the 0-1 special case that we call the Second-Price Matching
problem (2PM). Offline 2PM is APX-hard, and for online 2PM there is no
deterministic algorithm achieving a non-trivial competitive ratio and no
randomized algorithm achieving a competitive ratio better than 2. This
contrasts with the results for the analogous special case in the first-price
model, the standard bipartite matching problem, which is solvable in polynomial
time and which has deterministic and randomized online algorithms achieving
better competitive ratios. On the positive side, we provide a 2-approximation
for offline 2PM and a 5.083-competitive randomized algorithm for online 2PM.
The latter result makes use of a new generalization of a result on the
performance of the "Ranking" algorithm for online bipartite matching.


title: Silicon Photonics: The Inside Story

abstract:
  The electronic chip industry embodies the height of technological
sophistication and economics of scale. Fabricating inexpensive photonic
components by leveraging this mighty manufacturing infrastructure has fueled
intense interest in silicon photonics. If it can be done economically and in an
energy efficient manner, empowering silicon with optical functionality will
bring optical communications to the realm of computers where limitations of
metallic interconnects are threatening the industry's future. The field is
making stunning progress and stands to have a bright future, as long as the
community recognizes the real challenges, and maintains an open mind with
respect to its applications. This talk will review recent 'game changing'
developments and discuss promising applications beyond data communication. It
will conclude with recent observation of extreme-value statistical behavior in
silicon photonics, a powerful example of how scientific discoveries can
unexpectedly emerge in the course of technology development.


title:
Nonlinear transport through two-terminal strongly-correlated
  heterostructures: A dynamical-mean-field approach

abstract:
  The dynamical-mean-field method is applied to investigate the transport
properties of heterostructures consisting of a strongly-correlated electron
system connected to metallic leads. The spectral function inside the correlated
region is sensitive to the change of the interaction strength and bias voltage.
Because of this sensitivity, current vs voltage characteristics of such
heterostructures are rather nonlinear regardless of the detail of the potential
profile inside the correlated region. The electronic properties such as the
double occupancy are also changed by the bias voltage.


title:
Determination of the electronic structure of bilayer graphene from
  infrared spectroscopy results

abstract:
  We present an experimental study of the infrared conductivity, transmission,
and reflection of a gated bilayer graphene and their theoretical analysis
within the Slonczewski-Weiss-McClure (SWMc) model. The infrared response is
shown to be governed by the interplay of the interband and the intraband
transitions among the four bands of the bilayer. The position of the main
conductivity peak at the charge neutrality point is determined by the
interlayer tunneling frequency. The shift of this peak as a function of the
gate voltage gives information about less known parameters of the SWMc model,
in particular, those responsible for the electron-hole and sublattice
asymmetries. These parameter values are shown to be consistent with recent
electronic structure calculations for the bilayer graphene and the SWMc
parameters commonly used for the bulk graphite.


title:
Gravitational Radiation from Primordial Helical Inverse Cascade MHD
  Turbulence

abstract:
  We consider the generation of gravitational waves by primordial helical
inverse cascade magnetohydrodynamic (MHD) turbulence produced by bubble
collisions at the electroweak phase transition. We extend the previous study
\cite{kgr08} by considering both currently discussed models of MHD turbulence.
For popular electroweak phase transition parameter values, the generated
gravitational wave spectrum is only weakly dependent on the MHD turbulence
model. Compared to the unmagnetized electroweak phase transition case, the
spectrum of MHD-turbulence-generated gravitational waves peaks at lower
frequency with larger amplitude and can be detected by the proposed Laser
Interferometer Space Antenna


title:
Distributed Detection in Sensor Networks with Limited Range Multi-Modal
  Sensors

abstract:
  We consider a multi-object detection problem over a sensor network (SNET)
with limited range multi-modal sensors. Limited range sensing environment
arises in a sensing field prone to signal attenuation and path losses. The
general problem complements the widely considered decentralized detection
problem where all sensors observe the same object. In this paper we develop a
distributed detection approach based on recent development of the false
discovery rate (FDR) and the associated BH test procedure. The BH procedure is
based on rank ordering of scalar test statistics. We first develop scalar test
statistics for multidimensional data to handle multi-modal sensor observations
and establish its optimality in terms of the BH procedure. We then propose a
distributed algorithm in the ideal case of infinite attenuation for
identification of sensors that are in the immediate vicinity of an object. We
demonstrate communication message scalability to large SNETs by showing that
the upper bound on the communication message complexity scales linearly with
the number of sensors that are in the vicinity of objects and is independent of
the total number of sensors in the SNET. This brings forth an important
principle for evaluating the performance of an SNET, namely, the need for
scalability of communications and performance with respect to the number of
objects or events in an SNET irrespective of the network size. We then account
for finite attenuation by modeling sensor observations as corrupted by
uncertain interference arising from distant objects and developing robust
extensions to our idealized distributed scheme. The robustness properties
ensure that both the error performance and communication message complexity
degrade gracefully with interference.


title:
Compactness of Hankel operators and analytic discs in the boundary of
  pseudoconvex domains

abstract:
  Using several complex variables techniques, we investigate the interplay
between the geometry of the boundary and compactness of Hankel operators. Let f
be a function smooth up to the boundary on a smooth bounded pseudoconvex domain
D in C^n. We show that, if D is convex or the Levi form of the boundary of D is
of rank at least n-2, then compactness of the Hankel operator H_f implies that
f is holomorphic "along" analytic discs in the boundary. Furthermore, when D is
convex in C^2 we show that the condition on f is necessary and sufficient for
compactness of H_f


title: Fast C-K-R Partitions of Sparse Graphs

abstract:
  We present fast algorithms for constructing probabilistic embeddings and
approximate distance oracles in sparse graphs. The main ingredient is a fast
algorithm for sampling the probabilistic partitions of Calinescu, Karloff, and
Rabani in sparse graphs.


title:
Global well-posedness and inviscid limit for the modified Korteweg-de
  Vries-Burgers equation

abstract:
  Considering the Cauchy problem for the modified Korteweg-de Vries-Burgers
equation $u_t+u_{xxx}+\epsilon |\partial_x|^{2\alpha}u=2(u^{3})_x, u(0)=\phi$,
where $0<\epsilon,\alpha\leq 1$ and $u$ is a real-valued function, we show that
it is uniformly globally well-posed in $H^s (s\geq1)$ for all $\epsilon \in
(0,1]$. Moreover, we prove that for any $s\geq 1$ and $T>0$, its solution
converges in $C([0,T]; H^s)$ to that of the MKdV equation if $\epsilon$ tends
to 0.


title: Determining the WIMP mass from a single direct detection experiment

abstract:
  The energy spectrum of nuclear recoils in Weakly Interacting Massive Particle
(WIMP) direct detection experiments depends on the underlying WIMP mass
(strongly for light WIMPs, weakly for heavy WIMPs). We discuss how the accuracy
with which the WIMP mass could be determined by a single direct detection
experiment depends on the detector configuration and the WIMP properties. In
particular we examine the effects of varying the underlying WIMP mass, the
detector target nucleus, exposure, energy threshold and maximum energy, the
local velocity distribution and the background event rate and spectrum.


title: Crystal growth and superconductivity of FeSe_x

abstract:
  Single crystals FeSe_x have been grown in evacuated sealed quartz tube using
a NaCl/KCl flux. The products include two crystal structures of tetragon and
hexagon. The electronic transport and magnetic properties measurements of
FeSe_x single crystal exhibits a superconducting transition at about 10K.


title: Betweenness Centrality : Algorithms and Lower Bounds

abstract:
  One of the most fundamental problems in large scale network analysis is to
determine the importance of a particular node in a network. Betweenness
centrality is the most widely used metric to measure the importance of a node
in a network. In this paper, we present a randomized parallel algorithm and an
algebraic method for computing betweenness centrality of all nodes in a
network. We prove that any path-comparison based algorithm cannot compute
betweenness in less than O(nm) time.


title:
Quantum Connectivity of Space-Time and Gravitationally Induced
  Decorrelation of Entanglement

abstract:
  We discuss an alternative formulation of the problem of quantum optical
fields in a curved space-time using localized operators. We contrast the new
formulation with the standard approach and find observable differences for
entangled states. We propose an experiment in which an entangled pair of
optical pulses are propagated through non-uniform gravitational fields and find
that the new formulation predicts de-correlation of the optical entanglement
under experimentally realistic conditions.


title: First steps toward the geometry of cophylogeny

abstract:
  Here we introduce researchers in algebraic biology to the exciting new field
of cophylogenetics. Cophylogenetics is the study of concomitantly evolving
organisms (or genes), such as host and parasite species. Thus the natural
objects of study in cophylogenetics are tuples of related trees, instead of
individual trees. We review various research topics in algebraic statistics for
phylogenetics, and propose analogs for cophylogenetics. In particular we
propose spaces of cophylogenetic trees, cophylogenetic reconstruction, and
cophylogenetic invariants. We conclude with open problems.


title:
The Partition Function of a Wilson Loop in a Strongly Coupled $\mathcal
  N=4$ Supersymmetric Yang-Mills Plasma with Fluctuations

abstract:
  We examine the one-loop partition function describing the fluctuations of the
superstring in a Schwarzschild-AdS$_5\times S^5$ background. On the bosonic
side, we demonstrate the one-loop equivalence of the Nambu-Goto action and the
Polyakov action for a general worldsheet, while on the fermionic side, we
consider the reduction of the ten-dimensional Green-Schwarz fermion action to a
two-dimensional worldsheet action. We derive the partition functions of the
worldsheets corresponding to both straight and parallel Wilson lines. We show
that the UV divergences of the functional determinants in the thermal AdS
background are canceled.


title:
Reliable Communications with Asymmetric Codebooks: An Information
  Theoretic Analysis of Robust Signal Hashing

abstract:
  In this paper, a generalization of the traditional point-to-point to
communication setup, which is named as "reliable communications with asymmetric
codebooks", is proposed. Under the assumption of independent identically
distributed (i.i.d) encoder codewords, it is proven that the operational
capacity of the system is equal to the information capacity of the system,
which is given by $\max_{p(x)} I(U;Y)$, where $X, U$ and $Y$ denote the
individual random elements of encoder codewords, decoder codewords and decoder
inputs. The capacity result is derived in the "binary symmetric" case (which is
an analogous formulation of the traditional "binary symmetric channel" for our
case), as a function of the system parameters. A conceptually insightful
inference is made by attributing the difference from the classical Shannon-type
capacity of binary symmetric channel to the {\em gap} due to the codebook
asymmetry.


title: Emergent Collective Modes and Kinks in Electronic Dispersions

abstract:
  Recently, it was shown that strongly correlated metallic fermionic systems
[Nature Phys. 3, 168 (2007)] generically display kinks in the dispersion of
single fermions without the coupling to collective modes. Here we provide
compelling evidence that the physical origin of these kinks are emerging
internal collective modes of the fermionic systems. In the Hubbard model under
study these modes are identified to be spin fluctuations which are the
precursors of the spin excitations in the insulating phase. In spite of their
damping the emergent modes give rise to signatures very similar to features of
models including coupling to external modes.


title: On the dynamics of maximum extractable entanglement for open systems

abstract:
  In this work we study the dynamics of the maximum extractable entanglement
for a system composed of two qubits interacting either with two independent
thermal baths, a common thermal bath or a common squeezed bath. The states with
maximum entanglement are found applying filtering operations which transform
each state to a state in Bell diagonal form. We observe a revival of the
maximum extractable entanglement for common baths. It is also shown that for
some particular states in two independent baths at zero temperature, one can
partially recover the initial entanglement at any time.


title:
Correction to the Running of Gauge Couplings out of Extra Dimensional
  Gravity

abstract:
  We study the gravitational correction to the gauge couplings in the extra
dimension model where the gravity propagates in the (4+n)-dimensional bulk. We
show by explicit calculation in the background field method that the one-loop
correction coming from graviton Kaluza-Klein states is nontrivial and tends to
make the theory anti-asymptotically free. For the theory characterized with
asymptotic freedom, the correction will induce a nontrivial UV-stable fixed
point. This may lead to an interesting possibility that the non-abelian gauge
coupling constants $g_2$ and $g_3$ in the SM and that of the gravity
$g_{\kappa}$ unify at the fixed point in the limit of high energy scale.


title:
Nanomechanical-resonator-assisted induced transparency in a
  Cooper-pair-box system

abstract:
  We propose a scheme to demonstrate the electromagnetically induced
transparency (EIT) in a system of a superconducting Cooper-pair box coupled to
a nanomechanical resonator. In this scheme, the nanomechanical resonator plays
an important role to contribute additional auxiliary energy levels to the
Cooper-pair box so that the EIT phenomenon could be realized in such a system.
We call it here resonator-assisted induced transparency (RAIT). This RAIT
technique provides a detection scheme in a real experiment to measure physical
properties, such as the vibration frequency and the decay rate, of the coupled
nanomechanical resonator.


title: Is dark matter an extra-dimensional effect?

abstract:
  We investigate the possibility that the observed behavior of test particles
outside galaxies, which is usually explained by assuming the presence of dark
matter, is the result of the dynamical evolution of particles in higher
dimensional space-times. Hence, dark matter may be a direct consequence of the
presence of an extra force, generated by the presence of extra-dimensions,
which modifies the dynamic law of motion, but does not change the intrinsic
properties of the particles, like, for example, the mass (inertia). We discuss
in some detail several possible particular forms for the extra force, and the
acceleration law of the particles is derived. Therefore, the constancy of the
galactic rotation curves may be considered as an empirical evidence for the
existence of the extra dimensions.


title:
Randomized Distributed Configuration Management of Wireless Networks:
  Multi-layer Markov Random Fields and Near-Optimality

abstract:
  Distributed configuration management is imperative for wireless
infrastructureless networks where each node adjusts locally its physical and
logical configuration through information exchange with neighbors. Two issues
remain open. The first is the optimality. The second is the complexity. We
study these issues through modeling, analysis, and randomized distributed
algorithms. Modeling defines the optimality. We first derive a global
probabilistic model for a network configuration which characterizes jointly the
statistical spatial dependence of a physical- and a logical-configuration. We
then show that a local model which approximates the global model is a two-layer
Markov Random Field or a random bond model. The complexity of the local model
is the communication range among nodes. The local model is near-optimal when
the approximation error to the global model is within a given error bound. We
analyze the trade-off between an approximation error and complexity, and derive
sufficient conditions on the near-optimality of the local model. We validate
the model, the analysis and the randomized distributed algorithms also through
simulation.


title:
Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures
  by hard X-ray photoelectron spectroscopy

abstract:
  The conducting interface of LaAlO$_3$/SrTiO$_3$ heterostructures has been
studied by hard X-ray photoelectron spectroscopy. From the Ti~2$p$ signal and
its angle-dependence we derive that the thickness of the electron gas is much
smaller than the probing depth of 4 nm and that the carrier densities vary with
increasing number of LaAlO$_3$ overlayers. Our results point to an electronic
reconstruction in the LaAlO$_3$ overlayer as the driving mechanism for the
conducting interface and corroborate the recent interpretation of the
superconducting ground state as being of the Berezinskii-Kosterlitz-Thouless
type.


title: The Gauss-Dirichlet Orbit Number

abstract:
  Dirichlet computed in some particular cases the number of equivalence classes
of representations of a nonzero integer by a representative system for the
integral binary quadratic forms of a given discriminant. We complete this
computation.


title: Tachyonization of the $\La$CDM cosmological model

abstract:
  In this work a tachyonization of the $\Lambda$CDM model for a spatially flat
Friedmann-Robertson-Walker space-time is proposed. A tachyon field and a
cosmological constant are considered as the sources of the gravitational field.
Starting from a stability analysis and from the exact solutions for a standard
tachyon field driven by a given potential, the search for a large set of
cosmological models which contain the $\Lambda$CDM model is investigated. By
the use of internal transformations two new kinds of tachyon fields are derived
from the standard tachyon field, namely, a complementary and a phantom tachyon
fields. Numerical solutions for the three kinds of tachyon fields are
determined and it is shown that the standard and complementary tachyon fields
reproduces the $\Lambda$CDM model as a limiting case. The standard tachyon
field can also describe a transition from an accelerated to a decelerated
regime, behaving as an inflaton field at early times and as a matter field at
late times. The complementary tachyon field always behaves as a matter field.
The phantom tachyon field is characterized by a rapid expansion where its
energy density increases with time.


title:
Hexagonal eutectic solidification patterns operating near a marginal
  stability point

abstract:
  We study the long-time dynamics of hexagonal directional-solidification
patterns in bulk samples of a transparent eutectic alloy using an optical
method which permits real-time observation of the growth front. A slow
dilatation of the patterns due to a slight curvature of the isotherms drives
the system into a permanent regime, close to the threshold for the rod
splitting instability. Thus an apparently minor instrumental imperfection
suffices to maintain the system near a marginal stability point. This answers
the long-standing question of spacing selection in bulk eutectic growth.


title:
Experimental and modeling study of the low-temperature oxidation of
  large alkanes

abstract:
  This paper presents an experimental and modeling study of the oxidation of
large linear akanes (from C10) representative from diesel fuel from low to
intermediate temperature (550-1100 K) including the negative temperature
coefficient (NTC) zone. The experimental study has been performed in a
jet-stirred reactor at atmospheric pressure for n-decane and a
n-decane/n-hexadecane blend. Detailed kinetic mechanisms have been developed
using computer-aided generation (EXGAS) with improved rules for writing
reactions of primary products. These mechanisms have allowed a correct
simulation of the experimental results obtained. Data from the literature for
the oxidation of n-decane, in a jet-stirred reactor at 10 bar and in shock
tubes, and of n-dodecane in a pressurized flow reactor have also been correctly
modeled. A considerable improvement of the prediction of the formation of
products is obtained compared to our previous models. Flow rates and
sensitivity analyses have been performed in order to better understand the
influence of reactions of primary products. A modeling comparison between
linear alkanes for C8 to C16 in terms of ignition delay times and the formation
of light products is also discussed.


title: Gradings on symmetric composition algebras

abstract:
  The group gradings on the symmetric composition algebras over arbitrary
fields are classified. Applications of this result to gradings on the
exceptional simple Lie algebras are considered too.


title: Slowly rotating scalar field wormholes: the second order approximation

abstract:
  We discuss rotating wormholes in general relativity with a scalar field with
negative kinetic energy. To solve the problem, we use the assumption about slow
rotation. The role of a small dimensionless parameter plays the ratio of the
linear velocity of rotation of the wormhole's throat and the velocity of light.
We construct the rotating wormhole solution in the second order approximation
with respect to the small parameter. The analysis shows that the asymptotical
mass of the rotating wormhole is greater than that of the non-rotating one, and
the NEC violation in the rotating wormhole spacetime is weaker than that in the
non-rotating one.


title:
Integrable inhomogeneous NLS equations are equivalent to the standard
  NLS

abstract:
  A class of inhomogeneous nonlinear Schr\"odinger equations (NLS), claiming to
be novel integrable systems with rich properties continues appearing in PhysRev
and PRL. All such equations are shown to be not new but equivalent to the
standard NLS, which trivially explains their integrability features.


title: Precise Determinations of the Charm Quark Mass

abstract:
  In this contribution two recent analyses for the extraction of the charm
quark mass are discussed. Although they rely on completely different
experimental and theoretical input the two methods provide the same final
results for the charm quark mass and have an uncertainty of about 1%.


title: Ligand-Receptor Interactions

abstract:
  The formation and dissociation of specific noncovalent interactions between a
variety of macromolecules play a crucial role in the function of biological
systems. During the last few years, three main lines of research led to a
dramatic improvement of our understanding of these important phenomena. First,
combination of genetic engineering and X ray cristallography made available a
simultaneous knowledg of the precise structure and affinity of series or
related ligand-receptor systems differing by a few well-defined atoms. Second,
improvement of computer power and simulation techniques allowed extended
exploration of the interaction of realistic macromolecules. Third, simultaneous
development of a variety of techniques based on atomic force microscopy,
hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or
flexible transducers yielded direct experimental information of the behavior of
single ligand receptor bonds. At the same time, investigation of well defined
cellular models raised the interest of biologists to the kinetic and mechanical
properties of cell membrane receptors. The aim of this review is to give a
description of these advances that benefitted from a largely multidisciplinar
approach.


title: Fermionic contributions to the three-loop static potential

abstract:
  We consider the three-loop corrections to the static potential which are
induced by a closed fermion loop. For the reduction of the occurring integrals
a combination of the Gr\"obner and Laporta algorithm has been used and the
evaluation of the master integrals has been performed with the help of the
Mellin-Barnes technique. The fermionic three-loop corrections amount to 2% of
the tree-level result for top quarks, 8% for bottom quarks and 27% for the
charm quark system.