title:
Small Scale Magnetic Flux Emergence Observed with Hinode/Solar Optical
  Telescope

abstract:
  We observed small scale magnetic flux emergence in a sunspot moat region by
the Solar Optical Telescope (SOT) aboard the Hinode satellite. We analyzed
filtergram images observed in the wavelengths of Fe 6302 angstrom, G-band and
Ca II H. In Stokes I images of Fe 6302 angstrom, emerging magnetic flux were
recognized as dark lanes. In G-band, they showed their shapes almost the same
as in Stokes I images. These magnetic flux appeared as dark filaments in Ca II
H images. Stokes V images of Fe 6302 angstrom showed pairs of opposite
polarities at footpoints of each filament. These magnetic concentrations are
identified to correspond to bright points in G-band/Ca II H images. From the
analysis of time-sliced diagrams, we derived following properties of emerging
flux, which are consistent with the previous works. (1) Two footpoints separate
each other at a speed of 4.2 km/s during the initial phase of evolution and
decreases to about 1 km/s in 10 minutes later. (2) Ca II H filaments appear
almost simultaneously with the formation of dark lanes in Stokes I in the
observational cadence of 2 minutes. (3) The lifetime of the dark lanes in
Stokes I and G-band is 8 minutes, while that of Ca filament is 12 minutes. An
interesting phenomena was observed that an emerging flux tube expands laterally
in the photosphere with a speed of 3.8 km/s. Discussion on the horizontal
expansion of flux tube will be given with refernce to previous simulation
studies.


title:
Finite-size scaling functions for directed polymers confined between
  attracting walls

abstract:
  The exact solution of directed self-avoiding walks confined to a slit of
finite width and interacting with the walls of the slit via an attractive
potential has been calculated recently. The walks can be considered to model
the polymer-induced steric stabilisation and sensitised floculation of
colloidal dispersions. The large width asymptotics led to a phase diagram
different to that of a polymer attached to, and attracted to, a single wall.
The question that arises is: can one interpolate between the single wall and
two wall cases? In this paper we calculate the exact scaling functions for the
partition function by considering the two variable asymptotics of the partition
function for simultaneous large length and large width. Consequently, we find
the scaling functions for the force induced by the polymer on the walls. We
find that these scaling functions are given by elliptic theta-functions. In
some parts of the phase diagram there is more a complex crossover between the
single wall and two wall cases and we elucidate how this happens.


title:
Capillary-Driven Instability of Immiscible Fluid Interfaces Flowing in
  Parallel in Porous Media

abstract:
  When immiscible wetting and non-wetting fluids move in parallel in a porous
medium, an instability may occur at sufficiently high capillary numbers so that
interfaces between the fluids initially held in place by the porous medium are
mobilized. A boundary zone containing bubbles of both fluids evolve which has a
well defined thickness. This zone moves at constant average speed towards the
non-wetting fluid. A diffusive current of bubbles of non-wetting fluid into the
wetting fluid is set up.


title: Diffractive paths for weak localization in quantum billiards

abstract:
  We study the weak localization effect in quantum transport through a clean
ballistic cavity with regular classical dynamics. We address the question which
paths account for the suppression of conductance through a system where
disorder and chaos are absent. By exploiting both quantum and semiclassical
methods, we unambiguously identify paths that are diffractively backscattered
into the cavity (when approaching the lead mouths from the cavity interior) to
play a key role. Diffractive scattering couples transmitted and reflected paths
and is thus essential to reproduce the weak-localization peak in reflection and
the corresponding anti-peak in transmission. A comparison of semiclassical
calculations featuring these diffractive paths yields good agreement with full
quantum calculations and experimental data. Our theory provides system-specific
predictions for the quantum regime of few open lead modes and can be expected
to be relevant also for mixed as well as chaotic systems.


title:
Inflationary Hubble Parameter from the Gravitational Wave Spectrum in
  the General Slow-roll Approximation

abstract:
  Improved general slow-roll formulae giving the primordial gravitational wave
spectrum are derived in the present work. Also the first and second order
general slow-roll inverse formulae giving the Hubble parameter $H$ in terms of
the gravitational wave spectrum are derived. Moreover, the general slow-roll
consistency condition relating the scalar and tensor spectra is obtained.


title: Electrostatic trapping of metastable NH molecules

abstract:
  We report on the Stark deceleration and electrostatic trapping of $^{14}$NH
($a ^1\Delta$) radicals. In the trap, the molecules are excited on the
spin-forbidden $A ^3\Pi \leftarrow a ^1\Delta$ transition and detected via
their subsequent fluorescence to the $X ^3\Sigma^-$ ground state. The 1/e
trapping time is 1.4 $\pm$ 0.1 s, from which a lower limit of 2.7 s for the
radiative lifetime of the $a ^1\Delta, v=0,J=2$ state is deduced. The spectral
profile of the molecules in the trapping field is measured to probe their
spatial distribution. Electrostatic trapping of metastable NH followed by
optical pumping of the trapped molecules to the electronic ground state is an
important step towards accumulation of these radicals in a magnetic trap.


title: Neutral Current $\pi^0$ Production in MiniBooNE

abstract:
  This paper describes the analysis used to determine the neutral current
$\pi^0$ production in MiniBooNE in bins of momentum. Additionally, a
measurement of the relative coherent production of $\pi^0$s is discussed. The
coherent production rate is found to be (19.5 $\pm$1.1 (stat) $\pm$2.5 (sys))%
of the total exclusive neutral current $\pi^0$ production rate.


title: Hard spectator interactions in B to pi pi at order alpha_s^2

abstract:
  I compute the hard spectator interaction amplitude in $B\to\pi\pi$ at NLO
i.e. at O(\alpha_s^2). This special part of the amplitude, whose LO starts at
O(\alpha_s), is defined in the framework of QCD factorization. QCD
factorization allows to separate the short- and the long-distance physics in
leading power in an expansion in $\lqcd/m_b$, where the short-distance physics
can be calculated in a perturbative expansion in $\alpha_s$.
  In this calculation it is necessary to obtain an expansion of Feynman
integrals in powers of $\Lambda_\text{QCD}/m_b$. I will present a general
method to obtain this expansion in a systematic way once the leading power is
given as an input. This method is based on differential equation techniques and
easy to implement in a computer algebra system.
  The numerical impact on amplitudes and branching ratios is considered. The
NLO contributions of the hard spectator interactions are important but small
enough for perturbation theory to be valid.


title:
Infinitely divisible distributions over locally compact non-archimedean
  fields

abstract:
  The article is devoted to stochastic processes with values in
finite-dimensional vector spaces over infinite locally compact fields with
non-trivial non-archimedean valuations. Infinitely divisible distributions are
investigated. Theorems about their characteristic functionals are proved.
Particular cases are demonstrated.


title: Curvature-coupling dependence of membrane protein diffusion coefficients

abstract:
  We consider the lateral diffusion of a protein interacting with the curvature
of the membrane. The interaction energy is minimized if the particle is at a
membrane position with a certain curvature that agrees with the spontaneous
curvature of the particle. We employ stochastic simulations that take into
account both the thermal fluctuations of the membrane and the diffusive
behavior of the particle. In this study we neglect the influence of the
particle on the membrane dynamics, thus the membrane dynamics agrees with that
of a freely fluctuating membrane. Overall, we find that this curvature-coupling
substantially enhances the diffusion coefficient. We compare the ratio of the
projected or measured diffusion coefficient and the free intramembrane
diffusion coefficient, which is a parameter of the simulations, with analytical
results that rely on several approximations. We find that the simulations
always lead to a somewhat smaller diffusion coefficient than our analytical
approach. A detailed study of the correlations of the forces acting on the
particle indicates that the diffusing inclusion tries to follow favorable
positions on the membrane, such that forces along the trajectory are on average
smaller than they would be for random particle positions.


title:
Disconnected contributions to hadronic structure: a new method for
  stochastic noise reduction

abstract:
  We present a new method for reducing the stochastic noise of all-to-all
propagators based on stopping the inversion of the propagator before
convergence. The method is easy to implement, unbiased and independent of the
quark action. Applying this method to the calculation of disconnected loops
needed for hadronic structure observables we find savings in computer time of
factors of 4-12 depending on the operator inserted in the loop. When combined
with a hopping parameter expansion technique we obtain combined gains of up to
factors of 30 for some operators.


title: Positivity of Chern Classes for Reflexive Sheaves on P^N

abstract:
  It is well known that the Chern classes $c_i$ of a rank $n$ vector bundle on
$\PP^N$, generated by global sections, are non-negative if $i\leq n$ and vanish
otherwise. This paper deals with the following question: does the above result
hold for the wider class of reflexive sheaves? We show that the Chern numbers
$c_i$ with $i\geq 4$ can be arbitrarily negative for reflexive sheaves of any
rank; on the contrary for $i\leq 3$ we show positivity of the $c_i$ with weaker
hypothesis. We obtain lower bounds for $c_1$, $c_2$ and $c_3$ for every
reflexive sheaf $\FF$ which is generated by $H^0\FF$ on some non-empty open
subset and completely classify sheaves for which either of them reach the
minimum allowed, or some value close to it.


title:
Magnetic fluctuations and itinerant ferromagnetism in two-dimensional
  systems with van Hove singularities

abstract:
  We use the quasistatic approach to analyze the criterion of ferromagnetism
for two-dimensional (2D) systems with the Fermi level near Van Hove
singularities (VHS) of the electronic spectrum. It is shown that the spectrum
of spin excitations (paramagnons) is positively defined when the interaction I
between electrons and paramagnons, which corresponds to the Hubbard on-site
repulsion U, is sufficiently large. The critical interactions I_c and U_c
remain finite at Van Hove filling and exceed considerably their values obtained
from the Stoner criterion due to incommensurate spin fluctuations which are
important near the ferromagnetic quantum phase transition. Combining the
quasistatic approximation and the equation-of -motion method for the Green
functions we obtain the results for the electronic self-energy to first order
in the inverse number of spin components.


title:
Absence of logarithmic scaling in the ageing behaviour of the 4D
  spherical model

abstract:
  The non-equilibrium dynamics of the kinetic spherical model, quenched to
T<=T_c, with a non-conserved order-parameter is studied at its upper critical
dimension d=d*=4. In the scaling limit where both the waiting time s and the
observation time t are large and the ratio y=t/s>1 is fixed, the scaling
functions of the two-time autocorrelation and autoresponse functions do not
contain any logarithmic correction factors and the typical size of correlated
domains scales for large times as L(t) ~ t^0.5 .

categories: cond-mat.stat-mech hep-th math-ph math.MP


title: Theory of direct simulation Monte Carlo method

abstract:
  A treatment of direct simulation Monte Carlo method (DSMC) as a Markov
process with a master equation is given and the corresponding master equation
is derived. A hierarchy of equations for the reduced probability distributions
is derived from the master equation. An equation similar to the Boltzmann
equation for single particle probability distribution is derived using
assumption of molecular chaos. It is shown that starting from an uncorrelated
state, the system remains uncorrelated always in the limit $N\to \infty ,$
where $N$ is the number of particles. Simple applications of the formalism to
direct simulation money games are given as examples to the formalism. The
formalism is applied to the direct simulation of homogenous gases. It is shown
that appropriately normalized single particle probability distribution
satisfies the Boltzmann equation for simple gases and Wang Chang-Uhlenbeck
equation for a mixture of molecular gases. As a consequence of this development
we derive Birds no time counter algorithm. We extend the analysis to the
inhomogenous gases and define a new direct simulation algorithm for this case.
We show that single particle probability distribution satisfies the Boltzmann
equation in our algorithm in the limit $% N\to \infty ,$ $V_{k}\to 0,$ $\Delta
t\to 0$ where $% V_{k}$ is the volume $k^{th}$ cell. We also show that that our
algorithm and Bird's algorithm approach each other in the limit $N_{k}\to
\infty$ where $N_{k}$ is the number of particles in the volume $V_{k}$.


title:
Scattering below critical energy for the radial 4D Yang-Mills equation
  and for the 2D corotational wave map system

abstract:
  We describe the asymptotic behavior as time goes to infinity of solutions of
the 2 dimensional corotational wave map system and of solutions to the 4
dimensional, radially symmetric Yang-Mills equation, in the critical energy
space, with data of energy smaller than or equal to a harmonic map of minimal
energy. An alternative holds: either the data is the harmonic map and the
soltuion is constant in time, or the solution scatters in infinite time.


title: On decomposition numbers and Alvis-Curtis duality

abstract:
  We show that for general linear groups ${\rm GL}_n(q)$ as well as for
$q$-Schur algebras the knowledge of the modular Alvis-Curtis duality over
fields of characteristic $\ell$, $\ell \nmid q$, is equivalent to the knowledge
of the decomposition numbers.


title:
Variable Sine Algorithmic Analysis (VSAA): A new method of frequency
  analysis - Applications

abstract:
  A new method of frequency analysis is presented in detail. This new method -
Variable Sine Algorithmic Analysis, (VSAA) - is based on a single variable sine
function and it is powered by the simplex algorithm. It is used in cases of
phenomena triggered by a single mechanism, where Fourier Transform and Wavelet
Analysis fail to describe practically and efficiently. Applications are given
on the orbital period variation of two RS CVn type binaries: RS CVn itself and
CG Cyg. With the use of the Applegate's mechanism, the variation of their
subsurface magnetic field has been acquired.


title: Harvesting graphics power for MD simulations

abstract:
  We discuss an implementation of molecular dynamics (MD) simulations on a
graphic processing unit (GPU) in the NVIDIA CUDA language. We tested our code
on a modern GPU, the NVIDIA GeForce 8800 GTX. Results for two MD algorithms
suitable for short-ranged and long-ranged interactions, and a congruential
shift random number generator are presented. The performance of the GPU's is
compared to their main processor counterpart. We achieve speedups of up to 80,
40 and 150 fold, respectively. With newest generation of GPU's one can run
standard MD simulations at 10^7 flops/$.


title:
The interpretation of the Einstein-Rupp experiments and their influence
  on the history of quantum mechanics

abstract:
  The Einstein-Rupp experiments were proposed in 1926 by Albert Einstein to
study the wave versus particle nature of light. Einstein presented a
theoretical analysis of these experiments to the Berlin Academy together with
results of Emil Rupp, who claimed to have successfully carried them out.
However, as the preceding paper has claimed (HSPS 37 Suppl. (2007), 73-121),
Rupp's success was the result of scientific fraud. This paper will argue, after
exploring their interpretation, that the experiments were a relevant part of
the background to such celebrated contributions to quantum mechanics as Born's
statistical interpretation of the wave function and Heisenberg's uncertainty
principle. Yet, the Einstein-Rupp experiments have hardly received attention in
the history of quantum mechanics literature. In part, this is a consequence of
self-censorship in the physics community, enforced in the wake of the Rupp
affair. Self-censorship among historians of physics may however also have
played a role.


title:
Green functions and dimensional reduction of quantum fields on product
  manifolds

abstract:
  We discuss Euclidean Green functions on product manifolds P=NxM. We show that
if M is compact then the Euclidean field on P can be approximated by its zero
mode which is a Euclidean field on N. We estimate the remainder of this
approximation. We show that for large distances on N the remainder is small. If
P=R^{D-1}xS^{beta}, where S^{beta} is a circle of radius beta, then the result
reduces to the well-known approximation of the D dimensional finite temperature
quantum field theory to D-1 dimensional one in the high temperature limit.
Analytic continuation of Euclidean fields is discussed briefly.


title: Phase-ordering kinetics of two-dimensional disordered Ising models

abstract:
  The phase-ordering kinetics of the ferromagnetic two-dimensional Ising model
with uniform disorder is investigated by intensive Monte Carlo simulations.
Taking into account finite-time corrections to scaling, simple ageing behaviour
is observed in the two-time responses and correlators. The dynamical exponent z
and the form of the scaling functions only depend on the ratio eps/T, where eps
describes the width of the distribution of the disorder. The agreement of the
predictions of local scale-invariance generalised to z<> 2 for the two-time
scaling functions of response and correlations with the numerical data provides
a direct test of generalised Galilei-invariance.

categories: cond-mat.stat-mech cond-mat.dis-nn hep-th math-ph math.MP


title: Non-Markovian disentanglement dynamics of two-qubit system

abstract:
  We investigated the disentanglement dynamics of two-qubit system in
Non-Markovian approach. We showed that only the couple strength with the
environment near to or less than fine-structure constant 1/137, entanglement
appear exponential decay for a certain class of two-qubit entangled state.
While the coupling between qubit and the environment is much larger, system
always appears the sudden-death of entanglement even in the vacuum environment.


title: How does flow in a pipe become turbulent?

abstract:
  The transition to turbulence in pipe flow does not follow the scenario
familiar from Rayleigh-Benard or Taylor-Couette flow since the laminar profile
is stable against infinitesimal perturbations for all Reynolds numbers.
Moreover, even when the flow speed is high enough and the perturbation
sufficiently strong such that turbulent flow is established, it can return to
the laminar state without any indication of the imminent decay. In this
parameter range, the lifetimes of perturbations show a sensitive dependence on
initial conditions and an exponential distribution. The turbulence seems to be
supported by three-dimensional travelling waves which appear transiently in the
flow field. The boundary between laminar and turbulent dynamics is formed by
the stable manifold of an invariant chaotic state. We will also discuss the
relation between observations in short, periodically continued domains, and the
dynamics in fully extended puffs.


title: Jacobi's Last Multiplier and Lagrangians for Multidimensional Systems

abstract:
  We demonstrate that the formalism for the calculation of the Jacobi last
multiplier for a one-degree-of-freedom system extends naturally to systems of
more than one degree of freedom thereby extending results of Whittaker dating
from more than a century ago and Rao ({\it Proc Ben Math Soc} {\bf 2} (1940)
53-59) dating from almost seventy years ago. We illustrate the theory with an
application taken from the theory of coupled oscillators. We indicate how many
Lagrangians can be obtained for such a system.


title:
High Resolution $\lambda$=1mm CARMA Observations of Large Molecules in
  Orion-KL

abstract:
  We present high resolution, Combined Array for Research in Millimeter-Wave
Astronomy (CARMA), $\lambda$=1mm observations of several molecular species
toward Orion-KL. These are the highest spatial and spectral resolution 1mm
observations of these molecules to date. Our observations show that ethyl
cyanide [C$_2$H$_5$CN] and vinyl cyanide [C$_2$H$_3$CN] originate from multiple
cores near the Orion hot core and IRc7. Additionally we show that dimethyl
ether [(CH$_3$)$_2$O] and methyl formate [HCOOCH$_3$] originate from IRc5 and
IRc6 and that acetone [(CH$_3$)$_2$CO] originates only from areas where both
N-bearing and O-bearing species are present.


title:
Local-dephasing-induced entanglement sudden death in two-component
  finite-dimensional systems

abstract:
  Entanglement sudden death (ESD), the complete loss of entanglement in finite
time, is demonstrated to occur in a class of bipartite states of qu-d-it pairs
of any finite dimension d > 2, when prepared in so-called `isotropic states'
and subject to multi-local dephasing noise alone. This extends previous results
for qubit pairs [T. Yu, J. H. Eberly, Phys. Rev. Lett. 97, 140403 (2006)] to
all qu-d-it pairs with d > 2.


title:
Symmetry and magnetically driven ferroelectricity in rare-earth
  manganites RMnO3 (R=Gd, Tb, Dy)

abstract:
  This work investigates the magnetically driven ferroelectricity in
orthorhombic manganites RMnO3 (R=Gd, Dy or Tb) from the point of view of the
symmetry. The method adopted generalizes the one used to characterize the polar
properties of displacive modulated structures to the case of an irreducible
magnetic order parameter. The symmetry conditions for magnetically induced
ferroelectricity are established and the Landau-Devonshire free energy
functionals derived from general symmetry considerations. The ferroelectric
polarisation observed in DyMnO3 and TbMnO3 at zero magnetic field is explained
in terms of the symmetry of a reducible magnetic order parameter. The
polarisation rotation induced in these compounds by external magnetic fields
and the stabilization of a ferroelectric phase in GdMnO3 are accounted for by a
mechanism in which magnetization and polarization are secondary order
parameters that are not directly coupled but compete with each other through
their coupling to competing primary modulated order parameters.


title: A one-parameter family of dendriform identities

abstract:
  We prove a q-identity in the dendriform dialgebra of colored free
quasi-symmetric functions. For q=1, we recover identities due to Ebrahimi-Fard,
Manchon, and Patras, in particular the noncommutative Bohnenblust-Spitzer
identity.


title: Determining chiral couplings at NLO

abstract:
  We present a general method that allows to estimate the low-energy constants
of Chiral Perturbation Theory up to next-to-leading corrections in the 1/N(C)
expansion, that is, keeping full control of the renormalization scale
dependence. As a first step we have determined L(8) and C(38), the couplings
related to the difference of the two-point correlation functions of two scalar
and pseudoscalar currents, L(8)(mu_0) = (0.6 \pm 0.4) 10^{-3} and C(38)(mu_0) =
(2 \pm 6) 10^{-6}$, with mu_0 = 0.77 GeV. As in many effective approaches, one
of the main ingredients of this method is the matching procedure: some comments
related to this topic are presented here.


title: Gradient Representations and the Perception of Luminosity

abstract:
  The neuronal mechanisms that serve to distinguish between light-emitting and
light reflecting objects are largely unknown. It has been suggested that
luminosity perception implements a separate pathway in the visual system, such
that luminosity constitutes an independent perceptual feature. Recently, a
psychophysical study was conducted to address the question whether luminosity
has a feature status or not. However, the results of this study lend support to
the hypothesis that luminance gradients are instead a perceptual feature. Here,
I show how the perception of luminosity can emerge from a previously proposed
neuronal architecture for generating representations of luminance gradients.


title: Lie symmetries of multidimensional difference equations

abstract:
  A method is presented for calculating the Lie point symmetries of a scalar
difference equation on a two-dimensional lattice. The symmetry transformations
act on the equations and on the lattice. They take solutions into solutions and
can be used to perform symmetry reduction. The method generalizes one presented
in a recent publication for the case of ordinary difference equations. In turn,
it can easily be generalized to difference systems involving an arbitrary
number of dependent and independent variables.


title: Lambda-parameter of lattice QCD with Symanzik improved gluon actions

abstract:
  We compute the ratio Lambda_L/Lambda_MS, where the scale parameter Lambda_L
is associated with a lattice formulation of QCD. We consider a 3-parameter
family of gluon actions, which are most frequently used for O(a) improvement a`
la Symanzik. The gluon action is put togeter with standard discretizations for
fermions (Wilson/clover, overlap), to provide Lambda_L for several possible
combinations of fermion and gluon actions. We employ the background field
technique in order to calculate the 1PI 2-point function of the background
field; this leads to the coupling constant renormalization function, Z_g, at
1-loop level.
  Our results are obtained for an extensive range of values for the Symanzik
coefficients.


title: Spin-texture and magneto-roton excitations at nu=1/3

abstract:
  Neutral spin texture ST excitations at nu=1/3 are directly observed for the
first time by resonant inelastic light scattering. They are determined to
involve two simultaneous spin- flips. At low magnetic fields, the ST energy is
below that of the magneto-roton minimum. With increasing in-plane magnetic
field these modes energies cross at a critical ratio of the Zeeman and Coulomb
energies of eta_c=0.020 +- 0.001. Surprisingly, the intensity of the ST mode
grows with temperature in the range in which the magneto-roton modes collapse.
The temperature dependence is interpreted in terms of a competition between
coexisting phases supporting different excitations. We consider the role of the
ST excitations in activated transport at nu=1/3.


title: Analysis of two step nilsequences

abstract:
  Nilsequences arose in the study of the multiple ergodic averages associated
to Furstenberg's proof of Szemer\'edi's Theorem and have since played a role in
problems in additive combinatorics. Nilsequences are a generalization of almost
periodic sequences and we study which portions of the classical theory for
almost periodic sequences can be generalized for two step nilsequences. We
state and prove basic properties for 2-step nilsequences and give a
classification scheme for them.


title: Bicomplex quantum mechanics: I. The generalized Schr\"odinger equation

abstract:
  We introduce the set of bicomplex numbers $\mathbb{T}$ which is a commutative
ring with zero divisors defined by $\mathbb{T}=\{w_0+w_1
\bold{i_1}+w_2\bold{i_2}+w_3 \bold{j}| w_0,w_1,w_2,w_3 \in \mathbb{R}\}$ where
$\bold{i^{\text 2}_1}=-1, \bold{i^{\text 2}_2}=-1, \bold{j}^2=1,\
\bold{i_1}\bold{i_2}=\bold{j}=\bold{i_2}\bold{i_1}$. We present the conjugates
and the moduli associated with the bicomplex numbers. Then we study the
bicomplex Schr\"odinger equation and found the continuity equations. The
discrete symmetries of the system of equations describing the bicomplex
Schr\"odinger equation are obtained. Finally, we study the bicomplex Born
formulas under the discrete symetries. We obtain the standard Born's formula
for the class of bicomplex wave functions having a null hyperbolic angle.


title:
Local electronic structure and magnetic properties of LaMn0.5Co0.5O3
  studied by x-ray absorption and magnetic circular dichroism spectroscopy

abstract:
  We have studied the local electronic structure of LaMn0.5Co0.5O3 using
soft-x-ray absorption spectroscopy at the Co-L_3,2 and Mn-L_3,2 edges. We found
a high-spin Co^{2+}--Mn^{4+} valence state for samples with the optimal Curie
temperature. We discovered that samples with lower Curie temperatures contain
low-spin nonmagnetic Co^{3+} ions. Using soft-x-ray magnetic circular dichroism
we established that the Co^{2+} and Mn^{4+} ions are ferromagnetically aligned.
We revealed also that the Co^{2+} ions have a large orbital moment:
m_orb/m_spin ~ 0.47. Together with model calculations, this suggests the
presence of a large magnetocrystalline anisotropy in the material and predicts
a non-trivial temperature dependence for the magnetic susceptibility.


title:
Spin currents in rough graphene nanoribbons: Universal fluctuations and
  spin injection

abstract:
  We investigate spin conductance in zigzag graphene nanoribbons and propose a
spin injection mechanism based only on graphitic nanostructures. We find that
nanoribbons with atomically straight, symmetric edges show zero spin
conductance, but nonzero spin Hall conductance. Only nanoribbons with
asymmetrically shaped edges give rise to a finite spin conductance and can be
used for spin injection into graphene. Furthermore, nanoribbons with rough
edges exhibit mesoscopic spin conductance fluctuations with a universal value
of $\mathrm{rms} G_\mathrm{s}\approx 0.4 e/4\pi$.


title: Modular analogues of Jordan's theorem for finite linear groups

abstract:
  In 1878, Jordan showed that a finite subgroup of GL(n,C) contains an abelian
normal subgroup whose index is bounded by a function of n alone. Previously,
the author has given precise bounds. Here, we consider analogues for finite
linear groups over algebraically closed fields of positive characteristic l. A
larger normal subgroup must be taken, to eliminate unipotent subgroups and
groups of Lie type and characteristic l, and we show that generically the bound
is similar to that in characteristic 0 - being (n+1)!, or (n+2)! when l divides
(n+2) - given by the faithful representations of minimal degree of the
symmetric groups. A complete answer for the optimal bounds is given for all
degrees n and every characteristic l.


title: Bootstrap of means under stratified sampling

abstract:
  In a two-stage cluster sampling procedure, $n$ random populations are drawn
independently from independent populations and a sub-sample of observations is
taken in each of them. The estimator of the general mean of the observed
variables is asymptotically Gaussian and the asymptotic distributions of
several bootstrap versions of the normalized and studentized statistics are
studied. A weighted population resampling provides a good approximation and its
accuracy depends on the convergence rate of the sample size of the populations.


title: Recent results on 4-body, charm semileptonic decays

abstract:
  We summarize recent data on 4-body charm semileptonic decay concentrating on
\kklndk{} and \kpilndk{}. We begin with giving some motivation for the study of
these decays. We discuss several of the models traditionally used to describe
these decays and conclude by presenting a non-parametric analysis of \kpiendk{}
and its possible extension into non-parametric studies of \kpimndk{}.


title: Fermion Number Fractionization

abstract:
  Solitons emerge as non-perturbative solutions of non-linear wave equations in
classical and quantum theories. These are non-dispersive and localised packets
of energy-remarkable properties for solutions of non-linear differential
equations. In presence of such objects, the solutions of Dirac equation lead to
the curious phenomenon of "fractional fermion number", a number which under
normal conditions takes strictly integral values. In this article, we describe
this accidental discovery and its manifestation in polyacetylene chains, which
has lead to the development of organic conductors.


title: NLO jet production in k_T factorization

abstract:
  We discuss the inclusive production of jets in the central region of rapidity
in the context of k_T-factorization at next-to-leading order (NLO).
Calculations are performed in the Regge limit making use of the NLO BFKL
results. We introduce a jet cone definition and carry out a proper phase--space
separation into multi-Regge and quasi-multi-Regge kinematic regions. We discuss
two situations: scattering of highly virtual photons, which requires a
symmetric energy scale to separate impact factors from the gluon Green's
function, and hadron-hadron collisions, where a non-symmetric scale choice is
needed.


title:
Self-teleportation and its application on LOCC estimation and other
  tasks

abstract:
  A way to characterize quantum nonlocality is to see difference in the figure
of merit between LOCC optimal protocol and globally optimal protocol in doing
certain task, e.g., state estimation, state discrimination, cloning and
broadcasting. Especially, we focus on the case where $n$ tensor of unknown
states.
  Our conclusion is that separable pure states are more non-local than
entangled pure states. More specifically, the difference in the figure of the
merit is exponentially small if the state is entangled, and the exponent is log
of the largest Schmidt coefficient. On the other hand, in many cases,
estimation of separable states by LOCC is worse than the global optimal
estimate by $O(\frac{1}{n})$.
  To show that the gap is exponentially small for entangled states, we propose
self-teleportation protocol as the key component of construct of LOCC
protocols. Objective of the protocol is to transfer Alice's part of quantum
information by LOCC, using intrinsic entanglement of $| \phi_{\theta}>
^{\otimes n}$ without using any extra resources. This protocol itself is of
interest in its own right.


title:
Widespread Occurrence of Trenching Patterns in the Granulation Field:
  Evidence for Roll Convection?

abstract:
  Time-averaged series of granulation images are analysed using COLIBRI, a
purpose-adapted version of a code originally developed to detect straight or
curvilinear features in aerospace images. The algorithm of image processing
utilises a nonparametric statistical criterion that identifies a straight-line
segment as a linear feature (lineament) if the photospheric brightness at a
certain distance from this line is on both sides stochastically lower or higher
than at the line itself. Curvilinear features can be detected as chains of
lineaments, using a criterion modified in some way. Once the input parameters
used by the algorithm are properly adjusted, the algorithm highlights
``ridges'' and ``trenches'' in the relief of the brightness field, drawing
white and dark lanes. The most remarkable property of the trenching patterns is
a nearly-universally-present parallelism of ridges and trenches. Since the
material upflows are brighter than the downflows, the alternating parallel
light and dark lanes should reflect the presence of roll convection in the
subphotospheric layers. If the numerous images processed by us are
representative, the patterns revealed suggest a widespread occurrence of roll
convection in the outer solar convection zone. In particular, the roll systems
could form the fine structure of larger-scale, supergranular and/or
mesogranular convection flows. Granules appear to be overheated blobs of
material that could develop in convection rolls due to some instabilities of
roll motion.


title:
BFKL resummation effects in exclusive production of rho meson pairs at
  the ILC

abstract:
  We calculate the Born order cross-section for the exclusive production of rho
meson pairs in e+e- scattering in the Regge limit of QCD and we show the
feasibility of the measurement of this process at the ILC. We also investigate
the leading and next-to-leading order BFKL evolution, making this process a
very clean test of the BFKL resummation effects.


title:
Are there approximate relations among transverse momentum dependent
  distribution functions?

abstract:
  Certain exact relations among transverse momentum dependent parton
distribution functions due to QCD equations of motion turn into approximate
ones upon the neglect of pure twist-3 terms. On the basis of available data
from HERMES we test the practical usefulness of one such
``Wandzura-Wilczek-type approximation'', namely of that connecting
h_{1L}^{\perp(1)a}(x) to h_L^a(x), and discuss how it can be further tested by
future CLAS and COMPASS data.


title:
Higher Order Perturbations Around Backgrounds with One Non-Homogeneous
  Dimension

abstract:
  It is shown that perturbations around backgrounds with one non-homogeneous
dimension, namely of co-homogeneity 1, can be canonically simplified, a
property that is shown to hold to any order in perturbation theory. Recalling
that the problem naturally reduces to 1d, a procedure is described whereby for
each gauge function in 1d two 1d fields are eliminated from the action - one is
gauge and can be eliminated without a constraint and the other is auxiliary.
These results generalize the results of hep-th/0609001 from linear to
non-linear perturbations and they unify two cases of physical interest:
cosmological perturbations and perturbations to static spherically symmetric
backgrounds. An application to black strings is discussed in some detail.


title:
A new calibration of Galactic Cepheid Period-Luminosity relations from B
  to K bands, and a comparison to LMC PL relations

abstract:
  The universality of the Cepheid Period-Luminosity relations has been under
discussion since metallicity effects have been assumed to play a role in the
value of the intercept and, more recently, of the slope of these relations. The
goal of the present study is to calibrate the Galactic PL relations in various
photometric bands (from B to K) and to compare the results to the
well-established PL relations in the LMC. We use a set of 59 calibrating stars,
the distances of which are measured using five different distance indicators:
Hubble Space Telescope and revised Hipparcos parallaxes, infrared surface
brightness and interferometric Baade-Wesselink parallaxes, and classical
Zero-Age-Main-Sequence-fitting parallaxes for Cepheids belonging to open
clusters or OB stars associations. A detailed discussion of absorption
corrections and projection factor to be used is given. We find no significant
difference in the slopes of the PL relations between LMC and our Galaxy. We
conclude that the Cepheid PL relations have universal slopes in all photometric
bands, not depending on the galaxy under study (at least for LMC and Milky
Way). The possible zero-point variation with metal content is not discussed in
the present work, but an upper limit of 18.50 for the LMC distance modulus can
be deduced from our data.


title: Quantum Criticality in Dimerized Spin Ladders

abstract:
  We analyze a possibility of quantum criticality (gaplessness) in dimerized
antiferromagnetic two- and three-leg spin-1/2 ladders. Contrary to earlier
studies of these models, we examine different dimerization patterns in the
ladder. We find that ladders with the columnar dimerization order have lower
zero-temperature energies and they are always gapped. For the staggered
dimerization order, we find the quantum critical lines, in agreement with
earlier analyses. The bond mean-field theory we apply, demonstrates its
quantitative accuracy and agrees with available numerical results. We conclude
that unless some mechanism for locking dimerization into the energetically less
favorable staggered configuration is provided, the dimerized ladders do not
order into the phase where the quantum criticality occurs.


title: Series which are both max-plus and min-plus rational are unambiguous

abstract:
  Consider partial maps from the free monoid into the field of real numbers
with a rational domain. We show that two families of such series are actually
the same: the unambiguous rational series on the one hand, and the max-plus and
min-plus rational series on the other hand. The decidability of equality was
known to hold in both families with different proofs, so the above unifies the
picture. We give an effective procedure to build an unambiguous automaton from
a max-plus automaton and a min-plus one that recognize the same series.


title: The Dual-Axis Circumstellar Environment of the Type IIn Supernova 1997eg

abstract:
  We present multi-epoch spectral and spectropolarimetric observations of the
Type IIn supernova (SN) 1997eg that indicate the presence of a flattened
disk-like concentration of circumstellar material surrounding nonspherical
ejecta, with which the disk is misaligned. The polarization across the broad H
alpha, H beta, and He I 5876 lines of SN 1997eg forms closed loops when viewed
in the Stokes q-u plane. Such loops occur when the geometrical symmetry of one
or both of the Stokes parameters across spectral lines is broken, in this case
most likely by occultation of the ejecta by the equatorial circumstellar matter
concentration. The polarization of the narrow Balmer lines possesses an
intrinsic axis that differs by 12 degrees from that of the elongated ejecta and
probably indicates the orientation of the disk-like circumstellar material. The
existence of two different axes of symmetry in SN 1997eg suggests that neither
rotation of the progenitor nor the influence of a companion star can be the
sole mechanism creating a preferred axis within the supernova system. Our model
supports the emerging hypothesis that the progenitors of some Type IIn
supernovae are luminous blue variable stars, whose pre-supernova mass eruptions
form the circumstellar shells that physically characterize the SN IIn subclass.
These conclusions, which are independent of interstellar polarization effects,
would have been unobservable with only a single epoch of spectropolarimetry.


title: Bruhat order, smooth Schubert varieties, and hyperplane arrangements

abstract:
  The aim of this article is to link Schubert varieties in the flag manifold
with hyperplane arrangements. For a permutation, we construct a certain
graphical hyperplane arrangement. We show that the generating function for
regions of this arrangement coincides with the Poincare polynomial of the
corresponding Schubert variety if and only if the Schubert variety is smooth.
We give an explicit combinatorial formula for the Poincare polynomial. Our main
technical tools are chordal graphs and perfect elimination orderings.


title: Pauli spin-blockade in an InAs nanowire double quantum dot

abstract:
  We measure transport at finite bias through a double quantum dot formed by
top-gates in an InAs nanowire. Pauli spin-bockade is confirmed with several
electrons in the dot. This is expected due to the small exchange interactions
in InAs and the large singlet-triplet splitting, which can be measured and
tuned by a gate voltage.


title:
Correlations and clustering in the trading of members of the London
  Stock Exchange

abstract:
  This paper analyzes correlations in patterns of trading of different members
of the London Stock Exchange. The collection of strategies associated with a
member institution is defined by the sequence of signs of net volume traded by
that institution in hour intervals. Using several methods we show that there
are significant and persistent correlations between institutions. In addition,
the correlations are structured into correlated and anti-correlated groups.
Clustering techniques using the correlations as a distance metric reveal a
meaningful clustering structure with two groups of institutions trading in
opposite directions.


title:
A software for learning Information Theory basics with emphasis on
  Entropy of Spanish

abstract:
  In this paper, a tutorial software to learn Information Theory basics in a
practical way is reported. The software, called IT-tutor-UV, makes use of a
modern existing Spanish corpus for the modeling of the source. Both the source
and the channel coding are also included in this educational tool as part of
the learning experience. Entropy values of the Spanish language obtained with
the IT-tutor-UV are discussed and compared to others that were previously
calculated under limited conditions.


title:
Principal Components and Independent Component Analysis of Solar and
  Space Data

abstract:
  Principal Components Analysis (PCA) and Independent Component Analysis (ICA)
are used to identify global patterns in solar and space data. PCA seeks
orthogonal modes of the two-point correlation matrix constructed from a data
set. It permits the identification of structures that remain coherent and
correlated or which recur throughout a time series. ICA seeks for maximally
independent modes and takes into account all order correlations of the data. We
apply PCA to the interplanetary-magnetic-field polarity near one AU and to the
3.25R source-surface fields in the solar corona. The rotations of the
two-sector structures of these systems vary together to high accuracy during
the active interval of solar cycle 23. We then use PCA and ICA to hunt for
preferred longitudes in northern hemisphere, Carrington maps of magnetic
fields.


title:
The influence of the time delay of information flow on an economy
  evolution. The stock market analysis

abstract:
  The decision process requires information about the present state of the
system, but in economy acquiring data and processing them is an expensive and
time consuming process. Therefore the state of the system is measured and
announced at the end of the well defined time intervals. The model of a stock
market coupled with an economy is investigated and the role of the length of
the time delay of information flow investigated. It is shown that increasing
the time delay leads to collective behavior of agents and oscillations of
autocorrelations in absolute log-returns.


title: Algebraic Shifting and f-Vector Theory

abstract:
  This thesis focuses on algebraic shifting and its applications to f-vector
theory of simplicial complexes and more general graded posets. In particular,
several approaches and partial results concerning the g-conjecture for
simplicial spheres are presented here.


title:
Parametric Resonance Enhancement in Neutron Interferometry and Search
  for Non-Newtonian Gravity

abstract:
  The parametric resonance enhancement of the phase of neutrons due to
non-Newtonian anomalous gravitational is considered. The existence of such
resonances are confirmed by numerical calculations. A possible experimental
scheme for the observation of this effect is discussed based on an existing
neutron interferometer design.


title:
Analysis of equilibrium states of Markov solutions to the 3D
  Navier-Stokes equations driven by additive noise

abstract:
  We prove that every Markov solution to the three dimensional Navier-Stokes
equation with periodic boundary conditions driven by additive Gaussian noise is
uniquely ergodic. The convergence to the (unique) invariant measure is
exponentially fast.
  Moreover, we give a well-posedness criterion for the equations in terms of
invariant measures. We also analyse the energy balance and identify the term
which ensures equality in the balance.


title:
FERO (Finding Extreme Relativistic Objects): statistics of relativistic
  broad Fe K alpha lines in AGN

abstract:
  The properties of the relativistically broadened Fe K alpha line emitted in
Active Galactic Nuclei (AGN) are still debated among the AGN community. Recent
works seem to exclude that the broad Fe line is a common feature of AGN. The
analysis of a large sample composed by 157 XMM-Newton archival observations of
radio quiet AGN is presented here. This ongoing project is a development of the
work reported in Guainazzi et al. 2006.


title:
Magnetic bion condensation: A new mechanism of confinement and mass gap
  in four dimensions

abstract:
  In recent work, we derived the long-distance confining dynamics of certain
QCD-like gauge theories formulated on small $S^1 \times \R^3$ based on
symmetries, an index theorem, and Abelian duality. Here, we give the
microscopic derivation. The solution reveals a new mechanism of confinement in
QCD(adj) in the regime where we have control over both perturbative and
nonperturbative aspects. In particular, consider SU(2) QCD(adj) theory with $1
\leq n_f \leq 4$ Majorana fermions, a theory which undergoes gauge symmetry
breaking at small $S^1$. If the magnetic charge of the BPS monopole is
normalized to unity, we show that confinement occurs due to condensation of
objects with magnetic charge 2, not 1. Because of index theorems, we know that
such an object cannot be a two identical monopole configuration. Its net
topological charge must vanish, and hence it must be topologically
indistinguishable from the perturbative vacuum. We construct such non-self-dual
topological excitations, the magnetically charged, topologically null molecules
of a BPS monopole and ${\bar{\rm KK}}$ antimonopole, which we refer to as
magnetic bions. An immediate puzzle with this proposal is the apparent Coulomb
repulsion between the BPS-${\bar{\rm KK}}$ pair. An attraction which overcomes
the Coulomb repulsion between the two is induced by $2n_f$-fermion exchange.
Bion condensation is also the mechanism of confinement in $\N=1$ SYM on the
same four-manifold. The SU(N) generalization hints a possible hidden
integrability behind nonsupersymmetric QCD of affine Toda type, and allows us
to analytically compute the mass gap in the gauge sector. We currently do not
know the extension to $\R^4$.


title: Origami constructions

abstract: A characterization of real numbers constructible by paper folding.


title: The First Empirical Mass Loss Law for Population II Giants

abstract:
  Using the Spitzer IRAC camera we have obtained mid-IR photometry of the red
giant branch stars in the Galactic globular cluster 47 Tuc. About 100 stars
show an excess of mid-infrared light above that expected from their
photospheric emission. This is plausibly due to dust formation in mass flowing
from these stars. This mass loss extends down to the level of the horizontal
branch and increases with luminosity. The mass loss is episodic, occurring in
only a fraction of stars at a given luminosity. Using a simple model and our
observations we derive mass loss rates for these stars. Finally, we obtain the
first empirical mass loss formula calibrated with observations of Population II
stars. The dependence on luminosity of our mass loss rate is considerably
shallower than the widely used Reimers Law. The results presented here are the
first from our Spitzer survey of a carefully chosen sample of 17 Galactic
Globular Clusters, spanning the entire metallicity range from about one
hundredth up to almost solar.


title:
Azimuthal Asymmetric Distribution of Hadrons Inside a Jet at Hadron
  Collider

abstract:
  We study the azimuthal asymmetric distribution of hadrons inside a high
energy jet in the single transverse polarized proton proton scattering, coming
from the Collins effect multiplied by the quark transversity distribution. We
argue that the Collins function in this process is the same as that in the
semi-inclusive deep inelastic scattering. The experimental study of this
process will provide us important information on the quark transversity
distribution and test the universality of the fragmentation functions.


title: Detection of quantum critical points by a probe qubit

abstract:
  Quantum phase transitions occur when the ground state of a quantum system
undergoes a qualitative change when an external control parameter reaches a
critical value. Here, we demonstrate a technique for studying quantum systems
undergoing a phase transition by coupling the system to a probe qubit. It uses
directly the increased sensibility of the quantum system to perturbations when
it is close to a critical point. Using an NMR quantum simulator, we demonstrate
this measurement technique for two different types of quantum phase transitions
in an Ising spin chain.


title:
Observation of a 500meV Collective Mode in La$_{2-x}$Sr$_x$CuO$_4$ and
  Nd$_2$CuO$_4$

abstract:
  Utilizing resonant inelastic x-ray scattering, we report a previously
unobserved mode in the excitation spectrum of La$_{2-x}$Sr$_x$CuO$_4$ at 500
meV. The mode is peaked around the ($\pi$,0) point in reciprocal space and is
observed to soften, and broaden, away from this point. Samples with x=0, 0.01,
0.05, and 0.17 were studied. The new mode is found to be rapidly suppressed
with increasing Sr content and is absent at $x$=0.17, where it is replaced by a
continuum of excitations. The peak is only observed when the incident x-ray
polarization is normal to the CuO planes and is also present in Nd$_2$CuO$_4$.
We suggest possible explanations for this excitation.


title: Galois groups of the basic hypergeometric equations

abstract: In this paper we compute the Galois groups of basic hypergeometric equations.


title:
Infinite slabs and other weird plane symmetric space-times with constant
  positive density

abstract:
  We present the exact solution of Einstein's equation corresponding to a
static and plane symmetric distribution of matter with constant positive
density located below $z=0$. This solution depends essentially on two
constants: the density $\rho$ and a parameter $\kappa$. We show that this
space-time finishes down below at an inner singularity at finite depth. We
match this solution to the vacuum one and compute the external gravitational
field in terms of slab's parameters. Depending on the value of $\kappa$, these
slabs can be attractive, repulsive or neutral. In the first case, the
space-time also finishes up above at another singularity. In the other cases,
they turn out to be semi-infinite and asymptotically flat when $z\to\infty$.
  We also find solutions consisting of joining an attractive slab and a
repulsive one, and two neutral ones. We also discuss how to assemble a
"gravitational capacitor" by inserting a slice of vacuum between two such
slabs.


title:
On soliton structure of the Vakhnenko equation with a 'dissipative'
  term: a peculiar fission phenomenon

abstract:
  In the present work, we investigate the soliton structure of the Vakhnenko
equation with a 'dissipative' term, by means of the Hirota's method. As a
result, we unearth three kinds of soliton solutions depending upon the
dissipation parameter. We further find that the scattering behavior among such
structures exhibits a peculiar feature that may be the fission phenomenon.


title: Morse and Lyapunov Spectra and Dynamics on Flag Bundles

abstract:
  This paper studies characteristic exponents of flows in relation with the
dynamics of flows on flag bundles. The starting point is a flow on a principal
bundle with semi-simple group $G$. Projection against the Iwasawa decomposition
$G = KAN$ defines an additive cocycle over the flow with values in $\frak{a} =
\log A$. Its Lyapunov exponents (limits along trajectories) and Morse exponents
(limits along chains) are studied. It is proved a symmetric property of these
spectral sets, namely invariance under the Weyl group. It is proved also that
these sets are located in certain Weyl chambers, defined from the dynamics on
the associated flag bundles. As a special case linear flows on vector bundles
are considered.


title: Asymptotic entanglement in the discrete-time quantum walk

abstract:
  The coin-position entanglement generated by the evolution operator of a
discrete--time quantum walk converges, in the long time limit, to a well
defined value which depends on the initial state. We also discuss the
asymptotic bi-partite entanglement generated by several non-separable coin
operations for two coherent quantum walkers, for which the entropy of
entanglement increases logarithmically.


title:
Spontaneous gauge symmetry breaking in a supersymmetric Chern-Simons
  model

abstract:
  This works presents a perturbative analysis of the supersymmetric
Chern-Simons model in three spacetime dimensions coupled to a Higgs field,
using the superfield formalism. We study the spontaneous symmetry breaking of
the U(1) gauge symmetry and evaluate the first quantum corrections to the
effective action in the broken phase. We show that the infinite renormalization
of the gap equation is enough to ensure the renormalizability of the model at
the first loop level.


title:
Variable Stars in the Newly Discovered Milky Way Dwarf Spheroidal
  Satellite Canes Venatici I

abstract:
  We have identified 23 RR Lyrae stars and 3 possible Anomalous Cepheids among
84 candidate variables in the recently discovered Canes Venatici I dwarf
spheroidal galaxy. The mean period of 18 RRab type stars is <Pab> = 0.60
+/-0.01 days. This period, and the location of these stars in the
period-amplitude diagram, suggest that Canes Venatici I is likely an
Oosterhoff-intermediate system. The average apparent magnitude of the RR Lyrae
stars <V> = 22.17 +/-0.02 is used to obtain a precision distance estimate of
210 +7/-5 kpc, for an adopted reddening E(B-V)=0.03 mag. We present a B,V
color-magnitude diagram of Canes Venatici I that reaches V about 25 mag, and
shows that the galaxy has a mainly old stellar population with a metal
abundance near [Fe/H] = -2.0 dex. The width of the red giant branch and the
location of the candidate Anomalous Cepheids on the color-magnitude diagram may
indicate that the galaxy hosts a complex stellar population with stars from
about 13 Gyr to as young as about 0.6 Gyr.


title:
Unified Treatment of Mixed Vector-Scalar Screened Coulomb Potentials for
  Fermions

abstract:
  The problem of a fermion subject to a general mixing of vector and scalar
screened Coulomb potentials in a two-dimensional world is analyzed and
quantization conditions are found.


title:
Algorithmic and topological aspects of semi-algebraic sets defined by
  quadratic polynomial

abstract:
  In this thesis, we consider semi-algebraic sets over a real closed field $R$
defined by quadratic polynomials. Semi-algebraic sets of $R^k$ are defined as
the smallest family of sets in $R^k$ that contains the algebraic sets as well
as the sets defined by polynomial inequalities, and which is also closed under
the boolean operations (complementation, finite unions and finite
intersections). We prove new bounds on the Betti numbers as well as on the
number of different stable homotopy types of certain fibers of semi-algebraic
sets over a real closed field $R$ defined by quadratic polynomials, in terms of
the parameters of the system of polynomials defining them, which improve the
known results. We conclude the thesis with presenting two new algorithms along
with their implementations. The first algorithm computes the number of
connected components and the first Betti number of a semi-algebraic set defined
by compact objects in $\mathbb{R}^k$ which are simply connected. This algorithm
improves the well-know method using a triangulation of the semi-algebraic set.
Moreover, the algorithm has been efficiently implemented which was not possible
before. The second algorithm computes efficiently the real intersection of
three quadratic surfaces in $\mathbb{R}^3$ using a semi-numerical approach.


title: Scaling solution for small cosmic string loops

abstract:
  The equation governing the time evolution of the number density of loops in a
cosmic string network is a detailed balance determined by energy conservation.
We solve this equation with the inclusion of the gravitational radiation effect
which causes the loops to shrink (and eventually decay) as time elapses. The
solution approaches a scaling regime in which the total energy density in loops
remains finite, converging both in the infrared and in the ultraviolet.


title: Effect of frequency mismatched photons in quantum information processing

abstract:
  Many promising schemes for quantum information processing (QIP) rely on
few-photon interference effects. In these proposals, the photons are treated as
being indistinguishable particles. However, single photon sources are typically
subject to variation from device to device. Thus the photons emitted from
different sources will not be perfectly identical, and there will be some
variation in their frequencies. Here, we analyse the effect of this frequency
mismatch on QIP schemes. As examples, we consider the distributed QIP protocol
proposed by Barrett and Kok, and Hong-Ou-Mandel interference which lies at the
heart of many linear optical schemes for quantum computing. In the distributed
QIP protocol, we find that the fidelity of entangled qubit states depends
crucially on the time resolution of single photon detectors. In particular,
there is no reduction in the fidelity when an ideal detector model is assumed,
while reduced fidelities may be encountered when using realistic detectors with
a finite response time. We obtain similar results in the case of Hong-Ou-Mandel
interference -- with perfect detectors, a modified version of quantum
interference is seen, and the visibility of the interference pattern is reduced
as the detector time resolution is reduced. Our findings indicate that problems
due to frequency mismatch can be overcome, provided sufficiently fast detectors
are available.


title:
Perihelion precession and deflection of light in gravitational field of
  wormholes

abstract:
  Quite exotic relativistic objects known as wormholes are hypothetical
candidates for central machine of active galactic nuclei as well as black
holes. We find the magnitude of the perihelion precession and the deflection of
light in gravitational field of a wormhole and compare them with those for a
black hole. The impact parameter is taken to be much larger than the wormhole
throat size. We show that the relative difference between results for a black
hole and a wormhole may be significant and amount to tens of percent.


title: A convexity theorem for the real part of a Borel invariant subvariety

abstract:
  M. Brion proved a convexity result for the moment map image of an irreducible
subvariety of a compact integral Kaehler manifold preserved by the
complexification of the Hamiltonian group action. V. Guillemin and R. Sjamaar
generalized this result to irreducible subvarieties preserved only by a Borel
subgroup. In another direction, L. O'Shea and R. Sjamaar proved a convexity
result for the moment map image of the submanifold fixed by an antisymplectic
involution. Analogous to Guillemin and Sjamaar's generalization of Brion's
theorem, in this paper we generalize O'Shea and Sjamaar's result, proving a
convexity theorem for the moment map image of the involution fixed set of an
irreducible subvariety preserved by a Borel subgroup.


title:
Cosmological versions of Vaidya's radiating stellar exterior, an
  accelerating reference frame, and Kinnersley's photon rocket

abstract:
  The spacetimes for Vaidya's radiating stellar exterior and Kinnersley's
photon rocket in a cosmological background are obtained by performing the same
conformal transformation as is used to obtain the Robertson-Walker metric from
Minkowski spacetime. In the case of the cosmological radiating stellar
exterior, a two-fluid solution is found that obeys all of the energy conditions
and consists of a null fluid and a perfect fluid that asymptotically falls off
to the standard cosmological values for pressure and density at infinite
radius. For the cosmological photon rocket, the massless case is first
interpreted to obtain a solution for an accelerating cosmological reference
frame, and then the general case is interpreted: in both cases, a two-fluid
solution is found that consists of a null fluid and an imperfect fluid that
possesses heat conduction and anisotropic stress. The imperfect fluid appears
to contain an inhomogeneous dark energy component that acts to accelerate the
matter through space via a pressure gradient, but this component has negative
energy density on the trailing side of the rocket, meaning only the leading
side of the rocket is guaranteed to satisfy the weak and dominant energy
conditions. Unlike spacetimes that have rotation but no acceleration, the
cosmological photon rocket can serve as an example of a spacetime that
contradicts Mach's notion of acceleration, since an observer would see
empirical evidence of acceleration even though the matter does not accelerate
relative to the universe's background matter distribution.


title:
On Dynamics and Optimal Number of Replicas in Parallel Tempering
  Simulations

abstract:
  We study the dynamics of parallel tempering simulations, also known as the
replica exchange technique, which has become the method of choice for
simulation of proteins and other complex systems. Recent results for the
optimal choice of the control parameter discretization allow a treatment
independent of the system in question. Analyzing mean first passage times
across control parameter space, we find an expression for the optimal number of
replicas in simulations covering a given temperature range. Our results suggest
a particular protocol to optimize the number of replicas in actual simulations.

categories: cond-mat.stat-mech cond-mat.soft physics.comp-ph q-bio.BM


title:
Discovery of an M9.5 Candidate Brown Dwarf in the TW Hydrae Association
  - DENIS J124514.1-442907

abstract:
  We report the discovery of a fifth candidate substellar system in the ~5-10
Myr TW Hydrae Association - DENIS J124514.1-442907. This object has a NIR
spectrum remarkably similar to that of 2MASS J1139511-315921, a known TW Hydrae
brown dwarf, with low surface gravity features such as a triangular-shaped
H-band, deep H2O absorption, weak alkali lines, and weak hydride bands. We find
an optical spectral type of M9.5 and estimate a mass of <24 M_Jup, assuming an
age of ~5-10 Myr. While the measured proper motion for DENIS J124514.1-442907
is inconclusive as a test for membership, its position in the sky is coincident
with the TW Hydrae Association. A more accurate proper motion measurement,
higher resolution spectroscopy for radial velocity, and a parallax measurement
are needed to derive the true space motion and to confirm its membership.


title:
Functional Annotation of Genes in Saccharomyces cerevisiae based on
  Joint Betweenness

abstract: This paper has been withdrawn.


title: Neon and Sulfur Abundances of Planetary Nebulae in the Magellanic Clouds

abstract:
  The chemical abundances of neon and sulfur for 25 planetary nebulae (PNe) in
the Magellanic Clouds are presented. These abundances have been derived using
mainly infrared data from the Spitzer Space Telescope. The implications for the
chemical evolution of these elements are discussed. A comparison with similarly
obtained abundances of Galactic PNe and HII regions and Magellanic Clouds HII
regions is also given. The average neon abundances are 6.0x10(-5) and
2.7x10(-5) for the PNe in the Large and Small Magellanic Clouds respectively.
These are ~1/3 and 1/6 of the average abundances of Galactic planetary nebulae
to which we compare. The average sulfur abundances for the LMC and SMC are
respectively 2.7x10(-6) and 1.0x10(-6). The Ne/S ratio (23.5) is on average
higher than the ratio found in Galactic PNe (16) but the range of values in
both data sets is similar for most of the objects. The neon abundances found in
PNe and HII regions agree with each other. It is possible that a few (3-4) of
the PNe in the sample have experienced some neon enrichment, but for two of
these objects the high Ne/S ratio can be explained by their very low sulfur
abundances. The neon and sulfur abundances derived in this paper are also
compared to previously published abundances using optical data and
photo-ionization models.


title: Stellar Population Challenge: analysis of M67 with the VO

abstract:
  In this poster we present the analysis of the CMD of M67 (proposed in the
Stellar Population Challenge) performed with VO applications. We found that,
although the VO environment is still not ready to perform a complete analysis,
its use provides highly useful additional information for the analysis. Thanks
to the current VO framework, we are able to identify stars in the provided CMD
that are not suitable for isochrone fitting. Additionally, we can complete our
knowledge of this cluster extending the analysis to IR colors, which were not
provided in the original data but that are available thanks to the VO. On the
negative side, we find it difficult to access theoretical data from VO
applications, so, currently, it is not possible to perform completely the
analysis of the cluster inside the VO framework. However it is expected that
the situation will improve in a near future.


title:
General Conditions for Lepton Flavour Violation at Tree- and 1-Loop
  Level

abstract:
  In this work, we compile the necessary and sufficient conditions a theory has
to fulfill in order to ensure general lepton flavour conservation, in the
spirit of the Glashow-Weinberg criteria for the absence of flavour-changing
neutral currents. At tree-level, interactions involving electrically neutral
and doubly charged bosons are investigated. We also investigate flavour changes
at 1-loop level. In all cases we find that the essential theoretical
requirements can be reduced to a few basic conditions on the particle content
and the coupling matrices. For 1-loop diagrams, we also investigate how exactly
a GIM-suppression can occur that will strongly reduce the rates of lepton
flavour violating effects even if they are in principle present in a certain
theory. In all chapters, we apply our criteria to several models which can in
general induce lepton flavour violation, e.g. LR-symmetric models or the MSSM.
In the end we give a summarizing table of the obtained results, thereby
demonstrating the applicability of our criteria to a large class of models
beyond the Standard Model.


title: Synthesis models in the VO framework

abstract:
  The theory interest group in the International Virtual Observatory Alliance
(IVOA) has the goal of ensuring that theoretical data and services are taken
into account in the IVOA standards process. In this poster we present some of
the efforts carried out by this group to include evolutionary synthesis models
in the VO framework. In particular we present the VO tool PGos3, developed by
the INAOE (Mexico) and the Spanish Virtual Observatory which includes most of
public SSP models in the VO framework (e.g. VOSpec). We also describe the
problems related with the inclusion of synthesis models in the VO framework and
we try to encourage people to define the way in which synthesis models should
be described. This issue has implications not only for the inclusion of
synthesis models in the the VO framework but also for a proper usage of
synthesis models.


title:
M-Theory Through the Looking Glass: Tachyon Condensation in the E_8
  Heterotic String

abstract:
  We study the spacetime decay to nothing in string theory and M-theory. First
we recall a nonsupersymmetric version of heterotic M-theory, in which bubbles
of nothing -- connecting the two E_8 boundaries by a throat -- are expected to
be nucleated. We argue that the fate of this system should be addressed at weak
string coupling, where the nonperturbative instanton instability is expected to
turn into a perturbative tachyonic one. We identify the unique string theory
that could describe this process: The heterotic model with one E_8 gauge group
and a singlet tachyon. We then use worldsheet methods to study the tachyon
condensation in the NSR formulation of this model, and show that it induces a
worldsheet super-Higgs effect. The main theme of our analysis is the
possibility of making meaningful alternative gauge choices for worldsheet
supersymmetry, in place of the conventional superconformal gauge. We show in a
version of unitary gauge how the worldsheet gravitino assimilates the goldstino
and becomes dynamical. This picture clarifies recent results of Hellerman and
Swanson. We also present analogs of R_\xi gauges, and note the importance of
logarithmic CFT in the context of tachyon condensation.


title: Master equation approach to computing RVB bond amplitudes

abstract:
  We describe a "master equation" analysis for the bond amplitudes h(r) of an
RVB wavefunction. Starting from any initial guess, h(r) evolves (in a manner
dictated by the spin hamiltonian under consideration) toward a steady-state
distribution representing an approximation to the true ground state. Unknown
transition coefficients in the master equation are treated as variational
parameters. We illustrate the method by applying it to the J1-J2
antiferromagnetic Heisenberg model. Without frustration (J2=0), the amplitudes
are radially symmetric and fall off as 1/r^3 in the bond length. As the
frustration increases, there are precursor signs of columnar or plaquette VBS
order: the bonds preferentially align along the axes of the square lattice and
weight accrues in the nearest-neighbour bond amplitudes. The Marshall sign rule
holds over a large range of couplings, J2/J1 < 0.418. It fails when the r=(2,1)
bond amplitude first goes negative, a point also marked by a cusp in the ground
state energy. A nonrigourous extrapolation of the staggered magnetic moment
(through this point of nonanalyticity) shows it vanishing continuously at a
critical value J2/J1 = 0.447. This may be preempted by a first-order transition
to a state of broken translational symmetry.


title:
Calculation of DOS-Dependent Channel Potentials in FETs in the
  Saturation Condition

abstract:
  We calculated functions for the potential, Vch, in the channel of a field
effect transistor with various densities of the localized states (DOS) by using
a device simulator. In the saturation condition, Vch is found to fit
satisfactorily to the analytical function, Vch(y)=Vg(1-(1-y/L) k), where Vg is
the gate bias, y is the position along the channel, and L is the channel
length. The power k, which depends on the DOS, ranges from 0 to 0.5 even with
an extensive variation of DOS. As a result, the total induced charge density in
the saturation condition can be expressed a way similar to the linear condition
by introducing a correction factor, alpha, ranging between 0.65 and 1.0.


title: Multifield DBI Inflation and Non-Gaussianities

abstract:
  We analyze the trajectories for multifield DBI inflation, which can arise in
brane inflation models, and show that the trajectories are the same as in
typical slow roll inflation. We calculate the power spectrum and find that the
higher derivative terms of the DBI action lead to a suppression of the
contribution from the isocurvature perturbations. We also calculate the
bispectrum generated by the isocurvature perturbation, and find that it leads
to distinctive features.


title: Cosmological Cosmic Rays: Sharpening the Primordial Lithium Problem

abstract:
  Cosmic structure formation leads to large-scale shocked baryonic flows which
are expected to produce a cosmological population of structure-formation cosmic
rays (SFCRs). Interactions between SFCRs and ambient baryons will produce
lithium isotopes via \alpha+\alpha \to ^{6,7}Li. This pre-Galactic (but
non-primordial) lithium should contribute to the primordial 7Li measured in
halo stars and must be subtracted in order to arrive to the true observed
primordial lithium abundance. In this paper we point out that the recent halo
star 6Li measurements can be used to place a strong constraint to the level of
such contamination, because the exclusive astrophysical production of 6Li is
from cosmic-ray interactions. We find that the putative 6Li plateau, if due to
pre-Galactic cosmic-ray interactions, implies that SFCR-produced lithium
represents Li_{SFCR}/Li_{plateau}\approx 15% of the observed elemental Li
plateau. Taking the remaining plateau Li to be cosmological 7Li, we find a
revised (and slightly worsened) discrepancy between the Li observations and Big
Bang Nucleosynthesis predictions by a factor of ^7Li_{BBN}/^7Li_{plateau}
\approx 3.7. Moreover, SFCRs would also contribute to the extragalactic
gamma-ray background (EGRB) through neutral pion production. This gamma-ray
production is tightly related to the amount of lithium produced by the same
cosmic rays; the 6Li plateau limits the pre-Galactic (high-redshift) SFCR
contribution to be at the level of I_{\pi_{\gamma}SFCR}/I_{EGRB} < 5% of the
currently observed EGRB.


title: Monochromatic Neutrino Signals from Dark Matter Annihilation

abstract:
  Dark matter annihilations in the Sun to neutrino-antineutrino pairs have
striking signatures in neutrino detectors such as IceCube and KM3. We make a
model independent study of the signals after propagation of the neutrinos from
the center of the Sun to the Earth. A large spin-dependent DM capture cross
section in the Sun make the discovery prospects robust.


title: Coherent states in quantum cosmology

abstract:
  In the realm of a quantum cosmological model for dark energy in which we have
been able to construct a well-defined Hilbert space, a consistent coherent
state representation has been formulated that may describe the quantum state of
the universe and has a well-behaved semiclassical limit.


title: Colliders and Cosmology

abstract:
  Dark matter in variations of constrained minimal supersymmetric standard
models will be discussed. Particular attention will be given to the comparison
between accelerator and direct detection constraints.


title:
HST morphologies of local Lyman break galaxy analogs I: Evidence for
  starbursts triggered by merging

abstract:
  Heckman et al. (2005) used the Galaxy Evolution Explorer (GALEX) UV imaging
survey to show that there exists a rare population of nearby compact
UV-luminous galaxies (UVLGs) that closely resembles high redshift Lyman break
galaxies (LBGs). We present HST images in the UV, optical, and Ha, and
resimulate them at the depth and resolution of the GOODS/UDF fields to show
that the morphologies of UVLGs are also similar to those of LBGs. Our sample of
8 LBG analogs thus provides detailed insight into the connection between star
formation and LBG morphology. Faint tidal features or companions can be seen in
all of the rest-frame optical images, suggesting that the starbursts are the
result of a merger or interaction. The UV/optical light is dominated by
unresolved (~100-300 pc) super starburst regions (SSBs). A detailed comparison
with the galaxies Haro 11 and VV 114 at z=0.02 indicates that the SSBs
themselves consist of diffuse stars and (super) star clusters. The structural
features revealed by the new HST images occur on very small physical scales and
are thus not detectable in images of high redshift LBGs, except in a few cases
where they are magnified by gravitational lensing. We propose, therefore, that
LBGs are mergers of gas-rich, relatively low-mass (~10^10 Msun) systems, and
that the mergers trigger the formation of SSBs. If galaxies at high redshifts
are dominated by SSBs, then the faint end slope of the luminosity function is
predicted to have slope alpha~2. Our results are the most direct confirmation
to date of models that predict that the main mode of star formation in the
early universe was highly collisional.


title: Single Production of Heavy Charged Leptons at the ILC

abstract:
  This paper has been withdrawn by the authors due to a coding error and a
missed diagram. The calculation has been completely redone, with very different
results, and with an additional author, and will be submitted to the arxiv
shortly.


title: A refinement of the Kushnirenko-Bernstein estimate

abstract:
  A theorem of Kushnirenko and Bernstein shows that the number of isolated
roots of a system of polynomials in a torus is bounded above by the mixed
volume of the Newton polytopes of the given polynomials, and this upper bound
is generically exact. We improve on this result by introducing refined
combinatorial invariants of polynomials and a generalization of the mixed
volume of convex bodies: the mixed integral of concave functions. The proof is
based on new techniques and results from relative toric geometry.


title:
Unitary equivalence between ordinary intelligent states and generalized
  intelligent states

abstract:
  Ordinary intelligent states (OIS) hold equality in the Heisenberg uncertainty
relation involving two noncommuting observables {A, B}, whereas generalized
intelligent states (GIS) do so in the more generalized uncertainty relation,
the Schrodinger-Robertson inequality. In general, OISs form a subset of GISs.
However, if there exists a unitary evolution U that transforms the operators
{A, B} to a new pair of operators in a rotation form, it is shown that an
arbitrary GIS can be generated by applying the rotation operator U to a certain
OIS. In this sense, the set of OISs is unitarily equivalent to the set of GISs.
It is the case, for example, with the su(2) and the su(1,1) algebra that have
been extensively studied particularly in quantum optics. When these algebras
are represented by two bosonic operators (nondegenerate case), or by a single
bosonic operator (degenerate case), the rotation, or pseudo-rotation, operator
U corresponds to phase shift, beam splitting, or parametric amplification,
depending on two observables {A, B}.


title: Are There Enough Ionizing Photons to Reionize the Universe by z=6?

abstract:
  An estimate for the number of ionizing photons per baryon as a function of
redshift is computed based on the plausible extrapolation of the observed
galaxy UV luminosity function and the latest results on the properties of the
escape fraction of ionizing radiation. It is found that, if the escape fraction
for low mass galaxies (Mtot<10^{11}Msun) is assumed to be negligibly small, as
indicated by numerical simulations, then there are not enough ionizing photons
to reionize the universe by z=6 for the cosmology favored by the WMAP 3rd year
results, while the WMAP 1st year cosmology is marginally consistent with the
reionization requirement. The escape fraction as a function of galaxy mass
would have to be constant to within a factor of two for the whole mass range of
galaxies for reionization to be possible within the WMAP 3rd year cosmology.


title: Aspects of power corrections in hadron-hadron collisions

abstract:
  The program of understanding inverse-power law corrections to event shapes
and energy flow observables in e+ e- annihilation to two jets and DIS (1+1)
jets has been a significant success of QCD phenomenology over the last decade.
The important extension of this program to similar observables in hadron
collisions is not straightforward, being obscured by both conceptual and
technical issues. In this paper we shed light on some of these issues by
providing an estimate of power corrections to the inter-jet E_t flow
distribution in hadron collisions using the techniques that were employed in
the e+ e- annihilation and DIS cases.


title:
Final Report on ECCS/NSF Workshop on Quantum, Molecular and High
  Performance Modeling and Simulation for Devices and Systems (QMHP)

abstract:
  The National Science Foundation has identified a new thrust area in Quantum,
Molecular and High Performance Modeling and Simulation for Devices and Systems
(QMHP) in its core program. The main purpose of this thrust area is to capture
scientific opportunities that result from new fundamental cross-cutting
research involving three core research communities: (1) experts in modeling and
simulation of electronic devices and systems; (2) high performance computing
relevant to devices and systems; and (3) the quantum many-body principles
relevant to devices and systems. ECCS is especially interested in learning how
work in these areas could enable whole new classes of systems or devices,
beyond what is already under development in existing mainstream research. The
workshop helped identify technical areas that will enable fundamental
breakthroughs in the future. Modeling and simulation in the electronics and
optoelectronics areas, in general, have already resulted in important
fundamental scientific understanding and advances in design and development of
devices and systems. With the increasing emphasis on the next generation of
devices and systems at the nano, micro, and macro scales and the
interdisciplinary nature of the research, it is imperative that we explore new
mathematical models and simulation techniques. This workshop report provides a
better understanding of unmet emerging new opportunities to improve modeling,
simulation and design techniques for hybrid devices and systems. The purpose
the QMHP workshop was to define the field and strengthen the focus of the
thrust. The ultimate goal of the workshop was to produce a final report (this
document) that will be posted on the web so that the NSF can use it to guide
reviewers and researchers in this field.


title: Harmonic functions via restricted mean-value theorems

abstract:
  Let $f$ be a function on a bounded domain $\Omega \subseteq \mathbb{R}^n$ and
$\delta$ be a positive function on $\Omega$ such that $B(x,\delta(x))\subseteq
\Omega$. Let $\sigma(f)(x)$ be the average of $f$ over the ball
$B(x,\delta(x))$. The restricted mean-value theorems discuss the conditions on
$f,\delta,$ and $\Omega$ under which $\sigma(f)=f$ implies that $f$ is
harmonic. In this paper, we study the stability of harmonic functions with
respect to the map $\sigma$. One expects that, in general, the sequence
$\sigma^n(f)$ converges to a harmonic function. Among our results, we show that
if $\Omega$ is strongly convex (respectively $C^{2,\alpha}$-smooth for some
$\alpha\in [0,1]$), the function $\delta(x)$ is continuous, and $f\in C^0(\bar
\Omega)$ (respectively, $f\in C^{2,\alpha}(\bar \Omega)$), then $\sigma^n(f)$
converges to a harmonic function uniformly on $\bar \Omega$.


title:
Obstruction bundles over moduli spaces with boundary and the action
  filtration in symplectic field theory

abstract:
  Branched covers of orbit cylinders are the basic examples of holomorphic
curves studied in symplectic field theory. Since all curves with Fredholm index
one can never be regular for any choice of cylindrical almost complex
structure, we generalize the obstruction bundle technique of Taubes for
determining multiple cover contributions from Gromov-Witten theory to the case
of moduli spaces with boundary. Our result proves that the differential in
rational symplectic field theory and contact homology is strictly decreasing
with respect to the natural action filtration.


title:
Oxygen pumping II: Probing the Inhomogeneous Metal Enrichment at the
  Epoch of Reionization with High Frequency CMB Observations

abstract:
  At the epoch of reionization, when the high-redshift inter-galactic medium
(IGM) is being enriched with metals, the 63.2 micron fine structure line of OI
is pumped by the ~ 1300 AA soft UV background and introduces a spectral
distortion in the Cosmic Microwave Background (CMB). Here we use a toy model
for the spatial distribution of neutral oxygen, assuming metal bubbles surround
dark matter halos, and compute the fluctuations of this distortion, and the
angular power spectrum it imprints on the CMB. We discuss the dependence of the
power spectrum on the velocity of the winds polluting the IGM with metals, the
minimum mass of the halos producing these winds, and on the cosmic epoch when
the OI pumping occurs. We find that, although the clustering signal of the CMB
distortion is weak \delta y_{rms} ~ 10^{-7} (roughly corresponding to a
temperature anisotropy of few nK), it may be reachable in deep integrations
with high-sensitivity infrared detectors. Even without a detection, these
instruments should be able to useful constraints on the heavy element
enrichment history of the IGM.


title:
The Cosmological Constant is Probably Zero, and a Proof is Possibly
  Right

abstract:
  Hawking proposed that the cosmological constant is probably zero in quantum
cosmology. Duff claimed that Hawking's proof is invalidated. Using the right
configuration for the wave function of the universe, we provide a complete
proof.


title: FSR584 - a new globular cluster in the Galaxy?

abstract:
  We investigate the nature of the recently catalogued star cluster candidate
FSR584, which is projected in the direction of the molecular cloud W3 and may
be the nearest globular cluster to the Sun. 2MASS CMDs, the stellar radial
density profile, and proper motions are employed to derive fundamental and
structural parameters. The CMD morphology and the radial density profile show
that FSR584 is an old star cluster. With proper motions, the properties of
FSR584 are consistent with a metal-poor globular cluster with a well-defined
turnoff and evidence of a blue horizontal-branch. FSR584 might be a
Palomar-like halo globular cluster that is moving towards the Galactic plane.
The distance from the Sun is approx 1.4kpc, and it is located at approx 1kpc
outside the Solar circle. The radial density profile is characterized by a core
radius of rc=0.3+/-0.1 pc. However, we cannot exclude the possibility of an old
open cluster. Near-infrared photometry coupled to proper motions support the
scenario where FSR584 is a new globular cluster in the Galaxy. The absorption
is A_V=9.2+/-0.6$, which makes it a limiting object in the optical and explains
why it has so far been overlooked


title: Line crossing problem for biased monotonic random walks in the plane

abstract:
  In this paper, we study the problem of finding the probability that the
two-dimensional (biased) monotonic random walk crosses the line $y=\alpha x+d$,
where $\alpha,d \geq 0$. A $\beta$-biased monotonic random walk moves from
$(a,b)$ to $(a+1,b)$ or $(a,b+1)$ with probabilities $1/(\beta + 1)$ and
$\beta/(\beta + 1)$, respectively. Among our results, we show that if $\beta
\geq \lceil \alpha \rceil$, then the $\beta$-biased monotonic random walk,
starting from the origin, crosses the line $y=\alpha x+d$ for all $d\geq 0$
with probability 1.


title: Stick-Breaking Model for Variable-Range Hopping

abstract:
  We consider the optimal conduction path of the one-dimensional variable-range
hopping problem. We describe a hierarchical procedure for constructing the path
which is in excellent agreement with numerical results obtained from a
percolation approach. The advantage of the hierarchical construction is that it
is easier to analyse. We show that the distribution of hopping lengths is well
approximated by a model for the repeated breaking of a stick at its weakest
point, until the fragments are too strong to be broken.


title:
Yields from AGB Stars and their Impact on the Chemical Evolution of
  Dwarf Galaxies

abstract:
  By means of 2--D chemodynamical simulations, we study the evolution of dwarf
galaxies with structural parameters similar to IZw18 and to tidal dwarf
galaxies. Different sets of yields from intermediate-mass stars are tested, in
order to discover which one best reproduces the observed chemical compositions
(in particular for nitrogen). Different choices of yields from
intermediate-mass stars lead to differences of up to 0.3--0.6 dex, depending on
the assumptions. It is also shown that, given the dependence of the cooling
function on the metallicity, the dynamics of galaxies is also significantly
affected by the choice of nucleosynthetic yields.


title:
Photovoltaic Oscillations Due to Edge-Magnetoplasmon Modes in a
  Very-High Mobility 2D Electron Gas

abstract:
  Using very-high mobility GaAs/AlGaAs 2D electron Hall bar samples, we have
experimentally studied the photoresistance/photovoltaic oscillations induced by
microwave irradiation in the regime where both 1/B and B-periodic oscillations
can be observed. In the frequency range between 27 and 130 GHz we found that
these two types of oscillations are decoupled from each other, consistent with
the respective models that 1/B oscillations occur in bulk while the
B-oscillations occur along the edges of the Hall bars. In contrast to the
original report of this phenomenon (Ref. 1) the periodicity of the
B-oscillations in our samples are found to be independent of L, the length of
the Hall bar section between voltage measuring leads.


title: The Abelian Monodromy Extension Property for Families of Curves

abstract:
  Necessary and sufficient conditions are given (in terms of monodromy) for
extending a family of smooth curves over an open subset U of S to a family of
stable curves over S. More precisely, we introduce the abelian monodromy
extension (AME) property and show that the standard Deligne-Mumford
compactification is the unique, maximal AME compactification of the moduli
space of curves. We also show that the Baily-Borel compactification is the
unique, maximal projective AME compactification of the moduli space of abelian
varieties.


title: Gamma-ray emission from dark matter wakes of recoiled black holes

abstract:
  A new scenario for the emission of high-energy gamma-rays from dark matter
annihilation around massive black holes is presented. A black hole can leave
its parent halo, by means of gravitational radiation recoil, in a merger event
or in the asymmetric collapse of its progenitor star. A recoiled black hole
which moves on an almost-radial orbit outside the virial radius of its central
halo, in the cold dark matter background, reaches its apapsis in a finite time.
Near or at the apapsis passage, a high-density wake extending over a large
radius of influence, forms around the black hole. It is shown that significant
gamma-ray emission can result from the enhancement of neutralino annihilation
in these wakes. At its apapsis passage, a black hole is shown to produce a
flash of high-energy gamma-rays whose duration is determined by the mass of the
black hole and the redshift at which it is ejected. The ensemble of such black
holes in the Hubble volume is shown to produce a diffuse high-energy gamma-ray
background whose magnitude is compared to the diffuse emission from dark matter
haloes alone.


title:
Multiplier ideal sheaves, Nevanlinna theory, and diophantine
  approximation

abstract:
  This note states a conjecture for Nevanlinna theory or diophantine
approximation, with a sheaf of ideals in place of the normal crossings divisor.
This is done by using a correction term involving a multiplier ideal sheaf.
This new conjecture trivially implies earlier conjectures in Nevanlinna theory
or diophantine approximation, and in fact is equivalent to these conjectures.
Although it does not provide anything new, it may be a more convenient
formulation for some applications.


title: Chemistry in Protoplanetary Disks: A Sensitivity Analysis

abstract:
  We study how uncertainties in the rate coefficients of chemical reactions in
the RATE06 database affect abundances and column densities of key molecules in
protoplanetary disks. We randomly varied the gas-phase reaction rates within
their uncertainty limits and calculated the time-dependent abundances and
column densities using a gas-grain chemical model and a flaring steady-state
disk model. We find that key species can be separated into two distinct groups
according to the sensitivity of their column densities to the rate
uncertainties. The first group includes CO, C$^+$, H$_3^+$, H$_2$O, NH$_3$,
N$_2$H$^+$, and HCNH$^+$. For these species, the column densities are not very
sensitive to the rate uncertainties but the abundances in specific regions are.
The second group includes CS, CO$_2$, HCO$^+$, H$_2$CO, C$_2$H, CN, HCN, HNC
and other, more complex species, for which high abundances and abundance
uncertainties co-exist in the same disk region, leading to larger scatters in
the column densities. However, even for complex and heavy molecules, the
dispersion in their column densities is not more than a factor of ~4. We
perform a sensitivity analysis of the computed abundances to rate uncertainties
and identify those reactions with the most problematic rate coefficients. We
conclude that the rate coefficients of about a hundred of chemical reactions
need to be determined more accurately in order to greatly improve the
reliability of modern astrochemical models. This improvement should be an
ultimate goal for future laboratory studies and theoretical investigations.


title:
Comment on "Interaction-driven Relaxation of Two-level Systems in
  Glasses"

abstract:
  We comment on recent work of Bodea et al and discuss the numerical prefactor
in the interaction stimulated relaxation in amorphous solids.


title: Hochschild homology and cohomology of {\ell}^1({\mathbb Z}_+^k)

abstract:
  Building on the recent determination of the simplicial cohomology groups of
the convolution algebra ${\ell}^1({\mathbb Z}_+^k)$ [Gourdeau, Lykova, White,
2005] we investigate what can be said for cohomology of this algebra with more
general symmetric coefficients. Our approach leads us to a discussion of
Harrison homology and cohomology in the context of Banach algebras, and a
development of some of its basic features. As an application of our techniques
we reprove some known results on second-degree cohomology.


title:
Thermodynamic guidelines for the prediction of hydrogen storage
  reactions and their application to destabilized hydride mixtures

abstract:
  We propose a set of thermodynamic guidelines aimed at facilitating more
robust screening of hydrogen storage reactions. The utility of the guidelines
is illustrated by reassessing the validity of reactions recently proposed in
the literature, and through vetting a list of more than 20 candidate reactions
based on destabilized LiBH4 and Ca(BH4)2 borohydrides. Our analysis reveals
several new reactions having both favorable thermodynamics and relatively high
hydrogen densities (5-9 wt.% H2 & 85-100 g H2 /L), and demonstrates that
chemical intuition alone is not sufficient to identify valid reaction pathways.


title:
Rearrangements and radial graphs of constant mean curvature in
  hyperbolic space

abstract:
  We investigate the problem of finding smooth hypersurfaces of constant mean
curvature in hyperbolic space, which can be represented as radial graphs over a
subdomain of the upper hemisphere. Our approach is variational and our main
results are proved via rearrangement techniques.