title:
Proposal for a [111] Magnetization Plateau in the Spin Liquid State of
  Tb2Ti2O7

abstract:
  Despite a Curie-Weiss temperature $\theta_{\rm CW} \sim -14$ K, the Tb2Ti2O7
pyrochlore magnetic material lacks long range magnetic order down to at least
$T^*\approx 50$ mK. It has recently been proposed that the low temperature
collective paramagnetic or spin liquid regime of this material may be akin to a
spin ice state subject to both thermal and quantum fluctuations $-$ a {\it
quantum spin ice} (QSI) of sorts. Here we explore the effect of a magnetic
field ${\bm B}$ along the $[111]$ direction on the QSI state. To do so, we
investigate the magnetic properties of a microscopic model of Tb2Ti2O7 in an
independent tetrahedron approximation in a finite ${\bm B}$ along $[111]$. Such
a model describes semi-quantitatively the collective paramagnetic regime where
nontrivial spin correlations start to develop at the shortest lengthscale, that
is over a single tetrahedron, but where no long range order is yet present. Our
results show that a magnetization plateau develops at low temperatures as the
system develops ${\bm B}=0$ ferromagnetic spin-ice-like "two-in/two-out"
correlations at the shortest lengthscale. From these results, we are led to
propose that the observation of such a [111] magnetization plateau in Tb2Ti2O7
would provide compelling evidence for a QSI at ${\bm B}=0$ in this material and
help guide the development of a theory for the origin of its spin liquid state.


title:
Pythagorean Partition-Regularity and Ordered Triple Systems with the Sum
  Property

abstract:
  Is it possible to color the naturals with finitely many colors so that no
Pythagorean triple is monochromatic? This question is even open for two colors.
A natural strategy is to show that some small nonbipartite triple systems
cannot be realized as a family of Pythagorean triples. It suffices to consider
partial triple systems (PTS's), and it is therefore natural to consider the
Fano plane, the smallest nonbipartite PTS. We show that the Pythagorean triples
do not contain any Fano plane. In fact, our main result is that a much larger
family of "ordered" triple systems (viz. those with a certain "sum property")
do not contain any Steiner triple system (STS).


title: Fermions and Loops on Graphs. I. Loop Calculus for Determinant

abstract:
  This paper is the first in the series devoted to evaluation of the partition
function in statistical models on graphs with loops in terms of the
Berezin/fermion integrals. The paper focuses on a representation of the
determinant of a square matrix in terms of a finite series, where each term
corresponds to a loop on the graph. The representation is based on a fermion
version of the Loop Calculus, previously introduced by the authors for
graphical models with finite alphabets. Our construction contains two levels.
First, we represent the determinant in terms of an integral over anti-commuting
Grassman variables, with some reparametrization/gauge freedom hidden in the
formulation. Second, we show that a special choice of the gauge, called BP
(Bethe-Peierls or Belief Propagation) gauge, yields the desired loop
representation. The set of gauge-fixing BP conditions is equivalent to the
Gaussian BP equations, discussed in the past as efficient (linear scaling)
heuristics for estimating the covariance of a sparse positive matrix.

categories: cond-mat.stat-mech cond-mat.dis-nn cs.CC cs.IT hep-th math.IT


title: Theta Bodies for Polynomial Ideals

abstract:
  Inspired by a question of Lov\'asz, we introduce a hierarchy of nested
semidefinite relaxations of the convex hull of real solutions to an arbitrary
polynomial ideal, called theta bodies of the ideal. For the stable set problem
in a graph, the first theta body in this hierarchy is exactly Lov\'asz's theta
body of the graph. We prove that theta bodies are, up to closure, a version of
Lasserre's relaxations for real solutions to ideals, and that they can be
computed explicitly using combinatorial moment matrices. Theta bodies provide a
new canonical set of semidefinite relaxations for the max cut problem. For
vanishing ideals of finite point sets, we give several equivalent
characterizations of when the first theta body equals the convex hull of the
points. We also determine the structure of the first theta body for all ideals.


title:
Fermions and Loops on Graphs. II. Monomer-Dimer Model as Series of
  Determinants

abstract:
  We continue the discussion of the fermion models on graphs that started in
the first paper of the series. Here we introduce a Graphical Gauge Model (GGM)
and show that : (a) it can be stated as an average/sum of a determinant defined
on the graph over $\mathbb{Z}_{2}$ (binary) gauge field; (b) it is equivalent
to the Monomer-Dimer (MD) model on the graph; (c) the partition function of the
model allows an explicit expression in terms of a series over disjoint directed
cycles, where each term is a product of local contributions along the cycle and
the determinant of a matrix defined on the remainder of the graph (excluding
the cycle). We also establish a relation between the MD model on the graph and
the determinant series, discussed in the first paper, however, considered using
simple non-Belief-Propagation choice of the gauge. We conclude with a
discussion of possible analytic and algorithmic consequences of these results,
as well as related questions and challenges.


title: Elliptic curves with maximal Galois action on their torsion points

abstract:
  Given an elliptic curve E over a number field k, the Galois action on the
torsion points of E induces a Galois representation, \rho_E : Gal(\bar{k}/k)
\to GL_2(\hat{Z}). For a fixed number field k, we describe the image of \rho_E
for a "random" elliptic curve E over k. In particular, if k\neq Q is linearly
disjoint from the cyclotomic extension of Q, then \rho_E will be surjective for
"most" elliptic curves over k.


title:
Compact groups from the Millennium Simulations: I. Their Nature and the
  completeness of the Hickson sample

abstract:
  We identify compact groups of galaxies (CGs) within mock galaxy catalogues
from the Millennium Simulation at z=0 with three semi-analytic models (SAMs) of
galaxy formation. CGs are identified using the same 2D criteria as those
visually applied by Hickson (1982) to his CGs (HCGs), but with a brightest
galaxy magnitude limit, and the blending of close projected pairs. Half of the
mock CGs identified in projection contain at least 4 accordant velocities
(mvCGs), versus 70% for HCGs. In comparison to mvCGs, the HCGs are only 8%
complete at distances < 9000 km/s, missing the CGs with small angular sizes, a
strongly dominant galaxy, and (for one SAM) the CGs that are fainter and those
with lower surface brightness. We explore different ways to determine the
fraction of physically dense groups. Binding energy criteria turn out to be
inapplicable given the segregation between galaxies and dark matter particles.
We rely instead on the combination of the 3D length of the CGs (maximum real
space galaxy separation) and their elongation along the line-of-sight (ratio of
maximum line-of-sight to maximum projected separations), restricting ourselves
in both cases to smallest quartets within the CGs. We find that between 64% and
80% (depending on the SAM) of the mvCGs have 3D lengths shorter than 200 kpc/h,
between 71% and 80% have line-of-sight elongations less than 2, while between
59% and 76% have either 3D lengths shorter than 100 kpc/h or both lengths
shorter than 200 kpc/h and elongations smaller than 2. Therefore, chance
alignments (CAs) of galaxies concern at most 40% of the mvCGs. These CAs are
mostly produced from larger host groups, but a few have galaxies extending a
few Mpc beyond the host group. The mvCGs built with the Hickson selection with
(without) the close projected pair blending criterion have 10% higher (lower)
fractions of physically dense systems.


title:
Stochastic Process Associated with Traveling Wave Solutions of the
  Sine-Gordon Equation

abstract:
  Stochastic processes associated with traveling wave solutions of the
sine-Gordon equation are presented. The structure of the forward Kolmogorov
equation as a conservation law is essential in the construction and so is the
traveling wave structure. The derived stochastic processes are analyzed
numerically. An interpretation of the behaviors of the stochastic processes is
given in terms of the equation of motion.


title: A First Step to Convolutive Sparse Representation

abstract:
  In this paper an extension of the sparse decomposition problem is considered
and an algorithm for solving it is presented. In this extension, it is known
that one of the shifted versions of a signal s (not necessarily the original
signal itself) has a sparse representation on an overcomplete dictionary, and
we are looking for the sparsest representation among the representations of all
the shifted versions of s. Then, the proposed algorithm finds simultaneously
the amount of the required shift, and the sparse representation. Experimental
results emphasize on the performance of our algorithm.


title: Stein Block Thresholding For Image Denoising

abstract:
  In this paper, we investigate the minimax properties of Stein block
thresholding in any dimension $d$ with a particular emphasis on $d=2$. Towards
this goal, we consider a frame coefficient space over which minimaxity is
proved. The choice of this space is inspired by the characterization provided
in \cite{BorupNielsen} of family of smoothness spaces on $\mathbb{R}^d$, a
subclass of so-called decomposition spaces \cite{Feichtinger}. These smoothness
spaces cover the classical case of Besov spaces, as well as smoothness spaces
corresponding to curvelet-type constructions. Our main theoretical result
investigates the minimax rates over these decomposition spaces, and shows that
our block estimator can achieve the optimal minimax rate, or is at least
nearly-minimax (up to a $\log$ factor) in the least favorable situation.
Another contribution is that the minimax rates given here are stated for a
general noise sequence model in the transform coefficient domain beyond the
usual i.i.d. Gaussian case. The choice of the threshold parameter is
theoretically discussed and its optimal value is stated for some noise models
such as the (non-necessarily i.i.d.) Gaussian case. We provide a simple, fast
and a practical procedure. We also report a comprehensive simulation study to
support our theoretical findings. The practical performance of our Stein block
denoising compares very favorably to the BLS-GSM state-of-the art denoising
algorithm on a large set of test images. A toolbox is made available for
download on the Internet to reproduce the results discussed in this paper.


title: Generalized Calogero-Moser systems from rational Cherednik algebras

abstract:
  We consider ideals of polynomials vanishing on the W-orbits of the
intersections of mirrors of a finite reflection group W. We determine all such
ideals which are invariant under the action of the corresponding rational
Cherednik algebra hence form submodules in the polynomial module. We show that
a quantum integrable system can be defined for every such ideal for a real
reflection group W. This leads to known and new integrable systems of
Calogero-Moser type which we explicitly specify. In the case of classical
Coxeter groups we also obtain generalized Calogero-Moser systems with added
quadratic potential.


title: A Kurosh-Type Theorem for Type III Factors

abstract:
  We prove a generalization of N. Ozawa's Kurosh-type theorem to the setting of
free products of semiexact II_1 factors with respect to arbitrary (non-tracial)
faithful normal states. We are thus able to distinguish certain resulting type
III factors. For example, if M = LF_n \otimes LF_m and {\phi_i} is any sequence
of faithful normal states on M, then the l-various (M,\phi_1) * ... *
(M,\phi_l) are all mutually non-isomorphic.


title: Dynamics of liquid nanofilms

abstract:
  The van der Waals forces across a very thin liquid layer (nanofilm) in
contact with a plane solid wall make the liquid nonhomogeneous. The dynamics of
such flat liquid nanofilms is studied in isothermal case. The Navier-Stokes
equations are unable to describe fluid motions in very thin films. The notion
of surface free energy of a sharp interface separating gas and liquid layer is
disqualified. The concept of disjoining pressure replaces the model of surface
energy. In the nanofilm a supplementary free energy must be considered as a
functional of the density. The equation of fluid motions along the nanofilm is
obtained through the Hamilton variational principle by adding, to the
conservative forces, the forces of viscosity in lubrication approximation. The
evolution equation of the film thickness is deduced and takes into account the
variation of the disjoining pressure along the layer.


title: A non-Markovian decoherence theory for double dot charge qubit

abstract:
  In this paper, we develop a non-perturbation theory for describing
decoherence dynamics of electron charges in a double quantum dot gated by
electrodes. We extend the Feynman-Vernon influence functional theory to
fermionic environments and derive an exact master equation for the reduced
density matrix of electrons in the double dot for a general spectral density at
arbitrary temperature and bias. We then investigate the decoherence dynamics of
the double dot charge qubit with back-action of the reservoirs being fully
taken into account. Time-dependent fluctuations and leakage effects induced
from the dot-reservoir coupling are explicitly explored. The charge qubit
dynamics from the Markovian to non-Markovian regime is systematically studied
under various manipulating conditions. The decay behavior of charge qubit
coherence and the corresponding relaxation time $T_1$ and dephasing time $T_2$
are analyzed in details.


title: Modified Chaplygin Gas as Scalar Field and Holographic Dark Energy Model

abstract:
  We study the correspondence between field theoretic and holographic dark
energy density of the universe with the modified Chaplygin gas (MCG)
respectively both in a flat and non-flat FRW universe. We present an equivalent
representation of the MCG with a homogeneous minimally coupled scalar field by
constructing the corresponding potential. A new scalar field potential is
obtained here which is physically realistic and important for cosmological
model building. In addition we also present holographic dark energy model
described by the MCG. The dynamics of the corresponding holographic dark energy
field is determined by reconstructing the potential in a non-flat universe. The
stability of the holographic dark energy in this case in a non-flat universe is
also discussed.


title: Bandstructure Effects in Silicon Nanowire Hole Transport

abstract:
  Bandstructure effects in PMOS transport of strongly quantized silicon
nanowire field-effect-transistors (FET) in various transport orientations are
examined. A 20-band sp3d5s* spin-orbit-coupled (SO) atomistic tight-binding
model coupled to a self consistent Poisson solver is used for the valence band
dispersion calculation. A ballistic FET model is used to evaluate the
capacitance and current-voltage characteristics. The dispersion shapes and
curvatures are strong functions of device size, lattice orientation, and bias,
and cannot be described within the effective mass approximation. The anisotropy
of the confinement mass in the different quantization directions can cause the
charge to preferably accumulate in the (110) and secondly on the (112) rather
than (100) surfaces, leading to significant charge distributions for different
wire orientations. The total gate capacitance of the nanowire FET devices is,
however, very similar for all wires in all the transport orientations
investigated ([100], [110], [111]), and is degraded from the oxide capacitance
by ~30%. The [111] and secondly the [110] oriented nanowires indicate highest
carrier velocities and better ON-current performance compared to [100] wires.
The dispersion features and quantization behavior, although a complicated
function of physical and electrostatic confinement, can be explained at first
order by looking at the anisotropic shape of the heavy-hole valence band.


title: Nambu-Lie 3-Algebras on Fuzzy 3-Manifolds

abstract:
  We consider Nambu-Poisson 3-algebras on three dimensional manifolds $ {\cal
M}_{3} $, such as the Euclidean 3-space $R^{3}$, the 3-sphere $S^{3}$ as well
as the 3-torus $T^{3}$. We demonstrate that in the Clebsch-Monge gauge, the Lie
algebra of volume preserving diffeomorphisms $SDiff({\cal M}_{3})$ is identical
to the Nambu-Poisson algebra on ${\cal M}_{3}$. Moreover the fundamental
identity for the Nambu 3-bracket is just the commutation relation of $
SDiff({\cal M}_{3})$. We propose a quantization prescription for the
Nambu-Poisson algebra which provides us with the correct classical limit. As
such it possesses all of the expected classical properties constituting, in
effect, a concrete representation of Nambu-Lie 3-algebras.


title:
Perfect simulation and finitary coding for multicolor systems with
  interactions of infinite range

abstract:
  We consider a particle system on $Z^d$ with finite state space and
interactions of infinite range. Assuming that the rate of change is continuous
and decays sufficiently fast, we introduce a perfect simulation algorithm for
the stationary process. The algorithm follows from a representation of the
multicolor system as a finitary coding from a sequence of independent uniform
random variables. This implies that the process is exponentially ergodic. The
basic tool we use is a representation of the infinite range change rates as a
mixture of finite range change rates.


title:
Suzaku and XMM-Newton Observations of Diffuse X-ray Emission from the
  Eastern Tip Region of the Carina Nebula

abstract:
  The eastern tip region of the Carina Nebula was observed with the Suzaku XIS
for 77 ks to conduct a high-precision spectral study of extended X-ray
emission. XMM-Newton EPIC data of this region were also utilized to detect
point sources. The XIS detected strong extended X-ray emission from the entire
field-of-view with a 0.2--5 keV flux of $0.7\sim4\times10^{-14}$ erg s$^{-1}$
arcmin$^{-2}$. The emission has a blob-like structure that coincides with an
ionized gas filament observed in mid-infrared images. Contributions of
astrophysical backgrounds and the detected point sources were insignificant.
Thus the emission is diffuse in nature. The X-ray spectrum of the diffuse
emission was represented by a two-temperature plasma model with temperatures of
0.3 and 0.6 keV and an absorption column density of 2$\times10^{21}$ cm$^{-1}$.
The X-ray emission showed normal nitrogen-to-oxygen abundance ratios and a high
iron-to-oxygen abundance ratio. The spectrally deduced parameters, such as
temperatures and column densities, are common to the diffuse X-ray emission
near $\eta$ Car. Thus, the diffuse X-ray emission in these two fields may have
the same origin. The spectral fitting results are discussed to constrain the
origin in the context of stellar winds and supernovae.


title:
Lowest Order Constrained Variational Calculation of the Polarized
  Nuclear Matter with the Modern $AV_{18}$ Potential

abstract:
  The lowest order constrained variational method is applied to calculate the
polarized symmetrical nuclear matter properties with the modern $AV_{18}$
potential performing microscopic calculations. Results based on the
consideration of magnetic properties show no sign of phase transition to a
ferromagnetic phase.


title:
Polarized Neutron Matter: A Lowest Order Constrained Variational
  Approach

abstract:
  In this paper, we calculate some of the polarized neutron matter properties,
using the lowest order constrained variational method with the $AV_{18}$
potential and employing a microscopic point of view. A comparison is also made
between our results and those of other many-body techniques.


title:
Spin Polarized Asymmetric Nuclear Matter and Neutron Star Matter Within
  the Lowest Order Constrained Variational Method

abstract:
  In this paper, we calculate properties of the spin polarized asymmetrical
nuclear matter and neutron star matter, using the lowest order constrained
variational (LOCV) method with the $AV_{18}$, $Reid93$, $UV_{14}$ and $AV_{14}$
potentials. According to our results, the spontaneous phase transition to a
ferromagnetic state in the asymmetrical nuclear matter as well as neutron star
matter do not occur.


title:
Anomalous low-temperature magnetoelastic properties of nanogranular
  (CoFeB)$_{x}$-(SiO$_{2}$)$_{1-x}$

abstract:
  We report magnetostatic measurements for granulated films
(CoFeB)$_{x}$-(SiO$_{2}$)$_{1-x}$ with fabrication induced intraplanar
anisotropy. The measurements have been performed in the film plane in the wide
temperature interval 4.5$\div$300 K. They demonstrate that above films have
low-temperature anomaly below the percolation threshold for conductivity. The
essence of the above peculiarity is that below 100 K the temperature dependence
of coercive field for magnetization along easy direction deviates strongly from
Neel-Brown law. At temperature lowering, the sharp increase of coercivity is
observed, accompanied by the appearance of coercive field for magnetization
along hard direction in the film plane. We establish that observed effect is
related to the properties of individual ferromagnetic granules. The effect
weakens as granules merge into conglomerates at $x$ higher then percolation
threshold and disappears completely at $x>1$. We explain the above effect as a
consequence of the difference in thermal expansion coefficients of granule and
cover material. At temperature lowering this difference weakens the envelopment
of an individual granule by the cover matrix material, thus permitting to
realize the spontaneous magnetostriction of a granule. The latter induces an
additional anisotropy with new easy axis of a granule magnetization along the
external magnetic field direction. Our explanation is tested and corroborated
by the ferromagnetic resonance measurements in the films at $T$ = 300 K and $T$
= 77 K.


title:
Transport and infrared properties of SmFeAs(O1-xFx): from SDW to
  superconducting ordering

abstract:
  We report measurements of resistivity, magnetoresistivity, Hall effect,
Seebeck coefficient, infrared reflectivity of undoped SmFeAsO and lightly doped
SmFeAs(O0.93F0.07) oxypnictides. All the properties measured on SmFeAsO are
characterized by clear signatures of the magnetic instability. A
self-consistent picture emerges in which below the magnetic transition carrier
condensation occurs due to the opening of spin density wave (SDW) gap. This is
accompanied by the mobility increase of not gapped carriers due to the
suppression of electron-electron scattering. SmFeAs(O0.93F0.07) exhibits an
increase of the metallic character on cooling consistent with electron doping,
even though at room temperature values of all the properties nearly overlaps
with those of SmFeAsO. However, with temperature decrease all anomalies related
to the SDW instability are missed and the superconducting transition occurs.
This suggests that doping breaks abruptly the symmetries of the Fermi surface
inhibiting the SDW formation in favor of the superconducting transition, with
no substantial changes in the density of states or in the effective mass.


title: Light Nuclei as Quantized Skyrmions: Energy Spectra and Form Factors

abstract:
  We review the SU(2) Skyrme model and describe its topological soliton
solutions, which are called Skyrmions. Skyrmions provide a model of nuclei in
which the conserved topological charge is identified with the baryon number of
a nucleus. The semiclassical quantum theory of Skyrmions, in which they are
treated as rigid bodies spinning in space and isospace, is described. We derive
the energy spectra corresponding to various light nuclei, and predict a few new
states. We also calculate the electromagnetic form factors describing the
structure of the alpha-particle and lithium-6. Our recent reparametrization of
the model gives results that are in reasonable quantitative agreement with
experiment.


title:
On Bell, Suarez-Scarani, and Leggett experiments: Reply to a comment,
  and proposal for a new experiment

abstract:
  It is shown that the before-before (or Suarez-Scarani) experiment refutes
hidden variable models with a deterministic ("realistic") nonlocal part, and
the experimental violation of Leggett-type inequalities models with a random
nonlocal part and a biased random local one. Therefore the claim that
Groeblacher et al. present "an experimental test of nonlocal realism" [Nature,
446, 871-875 (2007)] is misleading, and Marek Zukowski's comment
[arXiv:0809.0072v1] misses the point. A new experiment is proposed.


title:
JDATATRANS for Array Obfuscation in Java Source Code to Defeat Reverse
  Engineering from Decompiled Codes

abstract:
  Software obfuscation or obscuring a software is an approach to defeat the
practice of reverse engineering a software for using its functionality
illegally in the development of another software. Java applications are more
amenable to reverse engineering and re-engineering attacks through methods such
as decompilation because Java class files store the program in a semi complied
form called 'byte' codes. The existing obfuscation systems obfuscate the Java
class files. Obfuscated source code produce obfuscated byte codes and hence two
level obfuscation (source code and byte code level) of the program makes it
more resilient to reverse engineering attacks. But source code obfuscation is
much more difficult due to richer set of programming constructs and the scope
of the different variables used in the program and only very little progress
has been made on this front. Hence programmers resort to adhoc manual ways of
obscuring their program which makes it difficult for its maintenance and
usability. To address this issue partially, we developed a user friendly tool
JDATATRANS to obfuscate Java source code by obscuring the array usages. Using
various array restructuring techniques such as 'array splitting', 'array
folding' and 'array flattening', in addition to constant hiding, our system
obfuscate the input Java source code and produce an obfuscated Java source code
that is functionally equivalent to the input program. We also perform a number
of experiments to measure the potency, resilience and cost incurred by our
tool.


title: Are photon momenta in left-handed materials reversed?

abstract:
  We develop a semiclassical theory to describe the photon momenta in
left-handed materials (LHMs). A single two-level atom is introduced as an
"explorer" to probe the momenta of photons. We demonstrate that the linear
momentum of the photons reverses its direction in LHMs. However the orbital
angular momentum is remains unreversed, although the wave-fronts reversed their
screwing fashion. We theoretically predict that the spin angular momentum is
also unreversed. The investigation of photon momenta will provide insights into
the fundamental properties of LHMs.


title: Cosmology from an AdS Schwarzschild black hole via holography

abstract:
  We derive the equations of cosmological evolution from an AdS Schwarzschild
black hole via holographic renormalization with appropriate boundary
conditions.


title:
First-principles study of the structural, elastic, and electronic
  properties of the cubic perovskite BaHfO$_3$

abstract:
  First principles study of structural, elastic, and electronic properties of
the cubic perovskitetype BaHfO$_3$ has been performed using the plane wave
ultrasoft pseudo-potential method based on density functional theory with
revised Perdew-Burke-Ernzerhof exchange-correlation functional of the
generalized gradient approximation (GGA-RPBE). The calculated equilibrium
lattice constant of this compound is in good agreement with the available
experimental and theoretical data reported in the literatures. The independent
elastic constants (\emph{C}$_{11}$, \emph{C}$_{12}$, and \emph{C}$_{44}$), bulk
modules \emph{B} and its pressure derivatives $B^{\prime}$, compressibility
$\beta$, shear modulus \emph{G}, Young's modulus \emph{Y}, Poisson's ratio
$\nu$, and Lam\'{e} constants ($\mu, \lambda$) are obtained and analyzed in
comparison with the available theoretical and experimental data for both the
singlecrystalline and polycrystalline BaHfO$_3$. The band structure
calculations show that BaHfO$_3$ is a indirect bandgap material (R-$\Gamma$ =
3.11 eV) derived basically from the occupied O 2\emph{p} and unoccupied Hf
5\emph{d} states, and it still awaits experimental confirmation. The density of
states (total, site-projected, and \emph{l}-decomposed) and the bonding charge
density calculations make it clear that the covalent bonds exist between the Hf
and O atoms and the ionic bonds exist between the Ba atoms and HfO$_3$ ionic
groups in BaHfO$_3$. From our calculations, it is shown that BaHfO$_3$ should
be promising as a candidate for synthesis and design of superhard materials due
to the covalent bonding between the transition metal Hf 5\emph{d} and O
2\emph{p} states.


title: Growth of rank 1 valuation semigroups

abstract:
  We consider the question of which semigroups can occur as the semigroup
$S_R(\nu)$ of positive values of a rank 1 valuation dominating a Noetherian
local ring $R$. We give a number of bounds of polynomial type on the growth of
$\phi(n)=S_R(\nu)\cap (0,n)$ for $n\in\NN$, starting with the upper bound of
$P_R(n)$, where $P_R(n)$ is the Hilbert function of $R$. This bound is
generalized to an extremely general bound for arbitrary rank valuations in the
paper "Semigroups of valuations on local rings, II", by Cutkosky and Teissier,
arXiv:0805.3788. This bound is already enough to give simple examples of rank 1
well ordered semigroups which are not the value semigroup $S_R(\nu)$ of a
valuation dominating a Noetherian local ring.
  In the case of rank 1, it is possible to give more precise estimates of
$\phi(n)$, which we prove in this paper. We also give examples showing that
many different rates of growth are possible for $\phi(n)$ on a regular local
ring of dimension 2, such as $n({\alpha}$ for any rational $\alpha$ with
$1\le\alpha\le 2$, and $n{log}(n)$.


title: Exploring the LHC medium with electromagnetic probes

abstract:
  Heavy-ion collisions will enter a new era with the start of the CERN Large
Hadron Collider (LHC). A first short run with proton-proton collisions at the
injection energy of 0.9 TeV will be followed by a longer one with $pp$
collisions at 10 TeV. First Pb-Pb collisions at $\sqrt{s_{NN}}$=5.5 TeV will
take place in 2009. Three experiments (ALICE, ATLAS, and CMS) will study both
$pp$ and Pb-Pb collisions. A selection of results showing the capabilities of
the three experiments for the study of the LHC medium with electromagnetic
probes is presented.


title: Recent HERA Results Sensitive to SUSY

abstract:
  Recent results of searches for new physics at HERA using the complete data
sample corresponding to about 0.5/fb per experiment are reviewed. Searches for
leptoquarks, isolated leptons (electrons, muons and taus) and a generic search
for new physics in many topologies are reported. No evidence for new physics is
found. The ep collisions at HERA are ideally suited to search for resonantly
produced squarks in SUSY with R-parity violation. It is highlighted how the
present results can be interpreted in this way.


title:
Shrinking Point Bifurcations of Resonance Tongues for Piecewise-Smooth,
  Continuous Maps

abstract:
  Resonance tongues are mode-locking regions of parameter space in which stable
periodic solutions occur; they commonly occur, for example, near Neimark-Sacker
bifurcations. For piecewise-smooth, continuous maps these tongues typically
have a distinctive lens-chain (or sausage) shape in two-parameter bifurcation
diagrams. We give a symbolic description of a class of "rotational" periodic
solutions that display lens-chain structures for a general $N$-dimensional map.
We then unfold the codimension-two, shrinking point bifurcation, where the
tongues have zero width. A number of codimension-one bifurcation curves emanate
from shrinking points and we determine those that form tongue boundaries.


title: Holographic indeterminacy and neutron stars

abstract:
  The holographic indeterminacy resulting from the quantization of spacetime
leads to an inherent uncertainty (lpL)1/2 in the relative positions of two
events, separated by a distance L, in a direction transverse to a null ray
connecting the events, where lP is the Planck length. The new indeterminacy
principle leads to a critical condition in which the holographic uncertainty in
the relative transverse positions of two diametrically opposed particles on the
surface a body becomes greater than the average distance between particles in
the body. The Chandrasekhar mass and the characteristic nuclear density emerge
as the minimum mass and density of a baryonic body that could meet the critical
criteria. Neutron stars are therefore identified as a class of bodies in which
holographic indeterminacy may have physical consequences.


title: On the linear wave regime of the Gross-Pitaevskii equation

abstract:
  We study a long wave-length asymptotics for the Gross-Pitaevskii equation
corresponding to perturbation of a constant state of modulus one. We exhibit
lower bounds on the first occurence of possible zeros (vortices) and compare
the solutions with the corresponding solutions to the linear wave equation or
variants. The results rely on the use of the Madelung transform, which yields
the hydrodynamical form of the Gross-Pitaevskii equation, as well as of an
augmented system.


title: The velocity-density relation in the spherical model

abstract:
  We study the cosmic velocity-density relation using the spherical collapse
model (SCM) as a proxy to non-linear dynamics. Although the dependence of this
relation on cosmological parameters is known to be weak, we retain the density
parameter Omega_m in SCM equations, in order to study the limit Omega_m -> 0.
We show that in this regime the considered relation is strictly linear, for
arbitrary values of the density contrast, on the contrary to some claims in the
literature. On the other hand, we confirm that for realistic values of Omega_m
the exact relation in the SCM is well approximated by the classic formula of
Bernardeau (1992), both for voids (delta<0) and for overdensities up to delta ~
3. Inspired by this fact, we find further analytic approximations to the
relation for the whole range delta from -1 to infinity. Our formula for voids
accounts for the weak Omega_m-dependence of their maximal rate of expansion,
which for Omega_m < 1 is slightly smaller that 3/2. For positive density
contrasts, we find a simple relation div v = 3 H_0 (Omega_m)^(0.6) [
(1+delta)^(1/6) - (1+delta)^(1/2) ], that works very well up to the turn-around
(i.e. up to delta ~ 13.5 for Omega_m = 0.25 and neglected Omega_Lambda). Having
the same second-order expansion as the formula of Bernardeau, it can be
regarded as an extension of the latter for higher density contrasts. Moreover,
it gives a better fit to results of cosmological numerical simulations.


title: Aspects of quantum phase transitions

abstract:
  A unified description of i) classical phase transitions and their remnants in
finite systems and ii) quantum phase transitions is presented. The ensuing
discussion relies on the interplay between, on the one hand, the thermodynamic
concepts of temperature and specific heat and on the other, the quantal ones of
coupling strengths in the Hamiltonian. Our considerations are illustrated in an
exactly solvable model of Plastino and Moszkowski [Il Nuovo Cimento {\bf 47},
470 (1978)].


title:
Effect of magnetic state on the $\gamma -\alpha$ transition in iron:
  First-principle calculations of the Bain transformation path

abstract:
  Energetics of the fcc ($\gamma$) - bcc ($\alpha$) lattice transformation by
the Bain tetragonal deformation is calculated for both magnetically ordered and
paramagnetic (disordered local moment) states of iron. The first-principle
computational results manifest a relevance of the magnetic order in a scenario
of the $\gamma$ - $\alpha$ transition and reveal a special role of the Curie
temperature of $\alpha$-Fe, $T_C$, where a character of the transformation is
changed. At a cooling down to the temperatures $T < T_C$ one can expect that
the transformation is developed as a lattice instability whereas for $T > T_C$
it follows a standard mechanism of creation and growth of an embryo of the new
phase. It explains a closeness of $T_C$ to the temperature of start of the
martensitic transformation, $M_s$.


title:
Noncommutative determinants, Cauchy-Binet formulae, and Capelli-type
  identities. I. Generalizations of the Capelli and Turnbull identities

abstract:
  We prove, by simple manipulation of commutators, two noncommutative
generalizations of the Cauchy-Binet formula for the determinant of a product.
As special cases we obtain elementary proofs of the Capelli identity from
classical invariant theory and of Turnbull's Capelli-type identities for
symmetric and antisymmetric matrices.


title:
Clustering of fermionic truncated expectation values via functional
  integration

abstract:
  I give a simple proof that the correlation functions of many-fermion systems
have a convergent functional Grassmann integral representation, and use this
representation to show that the cumulants of fermionic quantum statistical
mechanics satisfy l^1-clustering estimates.


title: The non-adiabatic pressure in general scalar field systems

abstract:
  We discuss the non-adiabatic or entropy perturbation, which controls the
evolution of the curvature perturbation in the uniform density gauge, for a
scalar field system minimally coupled to gravity with non-canonical action. We
highlight the differences between the sound and the phase speed in these
systems, and show that the non-adiabatic pressure perturbation vanishes in the
single field case, resulting in the conservation of the curvature perturbation
on large scales.


title: Metal-Insulator transitions in the periodic Anderson model

abstract:
  We solve the Periodic Anderson model in the Mott-Hubbard regime, using
Dynamical Mean Field Theory. Upon electron doping of the Mott insulator, a
metal-insulator transition occurs which is qualitatively similar to that of the
single band Hubbard model, namely with a divergent effective mass and a first
order character at finite temperatures. Surprisingly, upon hole doping, the
metal-insulator transition is not first order and does not show a divergent
mass. Thus, the transition scenario of the single band Hubbard model is not
generic for the Periodic Anderson model, even in the Mott-Hubbard regime.


title:
Mottness scenario for non-Fermi liquid behavior in the periodic Anderson
  model within Dynamical Mean Field Theory

abstract:
  We study the Mott metal-insulator transition in the Periodic Anderson Model
within Dynamical Mean Field Theory (DMFT). Near the quantum transition, we find
a non-Fermi liquid metallic state down to a vanishing temperature scale. We
identify the origin of the non-Fermi liquid behavior as due to magnetic
scattering of the doped carriers by the localized moments. The non-Fermi liquid
state can be tuned by either doping or external magnetic field. Our results
show that the coupling to spatial magnetic fluctuations (absent in DMFT) is not
a prerequisite to realize a non-Fermi liquid scenario for heavy fermion
systems.


title: Bifurcation from a normally degenerate manifold

abstract:
  Local bifurcation theory typically deals with the response of a degenerate
but isolated equilibrium state or periodic orbit of a dynamical system to
perturbations controlled by one or more independent parameters, and
characteristically uses tools from singularity theory. There are many
situations, however, in which the equilibrium state or periodic orbit is not
isolated but belongs to a manifold $S$ of such states, typically as a result of
continuous symmetries in the problem. In this case the bifurcation analysis
requires a combination of local and global methods, and is most tractable in
the case of normal nondegeneracy, that is when the degeneracy is only along $S$
itself and the system is nondegenerate in directions normal to $S$.
  In this paper we consider the consequences of relaxing normal nondegeneracy,
which can generically occur within 1-parameter families of such systems. We pay
particular attention to the simplest but important case where $\dim S=1$ and
where the normal degeneracy occurs with corank 1. Our main focus is on uniform
degeneracy along $S$, although we also consider aspects of the branching
structure for solutions when the degeneracy varies at different places on $S$.
The tools are those of singularity theory adapted to global topology of $S$,
which allow us to explain the bifurcation geometry in natural way. In
particular, we extend and give a clear geometric setting for earlier analytical
results of Hale and Taboas.


title: Optimal L$^1$-bounds for submartingales

abstract:
  The optimal function $f$ satisfying
  $$
  \mathbb{E} |\sum_{1}^n X_i |
  \ge f(\mathrbb{E}|X_1|,...,\mathbb{E}|X_n|)
  $$ for every martingale $(X_1,X_1+X_2, ...,\sum_{i=1}^n X_i)$ is shown to be
given by $$ f(a) = \max \Big\{a_k-\sum_{i=1}^{k-1} a_i\Big\}_{k=1}^n \cup
\Big\{\frac {a_k}2\Big\}_{k=3}^n $$ for $a\in{[0,\infty[}^n_{}$. A similar
result is obtained for submartingales $(0,X_1,X_1+X_2,..., \sum_{i=1}^n X_i)$.
The optimality proofs use a convex-analytic comparison lemma of independent
interest.


title: Triangleland. II. Quantum Mechanics of Pure Shape

abstract:
  Relational particle models are of value in the absolute versus relative
motion debate. They are also analogous to the dynamical formulation of general
relativity, and as such are useful for investigating conceptual strategies
proposed for resolving the problem of time in quantum general relativity.
Moreover, to date there are few explicit examples of these at the quantum
level. In this paper I exploit recent geometrical and classical dynamics work
to provide such a study based on reduced quantization in the case of pure shape
(no scale) in 2-d for 3 particles (triangleland) with multiple harmonic
oscillator type potentials. I explore solutions for these making use of exact,
asymptotic, perturbative and numerical methods. An analogy to the mathematics
of the linear rigid rotor in a background electric field is useful throughout.
I argue that further relational models are accessible by the methods used in
this paper, and for specific uses of the models covered by this paper in the
investigation of the problem of time (and other conceptual and technical
issues) in quantum general relativity.


title: Unitary perturbation theory approach to real-time evolution problems

abstract:
  We discuss a new analytical approach to real-time evolution in quantum
many-body systems. Our approach extends the framework of continuous unitary
transformations such that it amounts to a novel solution method for the
Heisenberg equations of motion for an operator. It is our purpose to illustrate
the accuracy of this approach by studying dissipative quantum systems on all
time scales. In particular, we obtain results for non-equilibrium correlation
functions for general initial conditions. We illustrate our ideas for the
exactly solvable dissipative oscillator, and, as a non-trivial model, for the
dissipative two-state system.


title: Switching path distribution in multi-dimensional systems

abstract:
  We explore the distribution of paths followed in fluctuation-induced
switching between coexisting stable states. We introduce a quantitative
characteristic of the path distribution in phase space that does not require a
priori knowledge of system dynamics. The theory of the distribution is
developed and its direct measurement is performed in a micromechanical
oscillator driven into parametric resonance. The experimental and theoretical
results on the shape and position of the distribution are in excellent
agreement, with no adjustable parameters. In addition, the experiment provides
the first demonstration of the lack of time-reversal symmetry in switching of
systems far from thermal equilibrium. The results open the possibility of
efficient control of the switching probability based on the measured narrow
path distribution.


title:
The resonant structure of Jupiter's trojan asteroids-II. What happens
  for different configurations of the planetary system

abstract:
  In a previous paper, we have found that the resonance structure of the
present Jupiter Trojan swarms could be split up into four different families of
resonances. Here, in a first step, we generalize these families in order to
describe the resonances occurring in Trojan swarms embedded in a generic
planetary system. The location of these families changes under a modification
of the fundamental frequencies of the planets and we show how the resonant
structure would evolve during a planetary migration. We present a general
method, based on the knowledge of the fundamental frequencies of the planets
and on those that can be reached by the Trojans, which makes it possible to
predict and localize the main events arising in the swarms during migration. In
particular, we show how the size and stability of the Trojan swarms are
affected by the modification of the frequencies of the planets. Finally, we use
this method to study the global dynamics of the Jovian Trojan swarms when
Saturn migrates outwards. Besides the two resonances found by Morbidelli et al
(2005) which could have led to the capture of the current population just after
the crossing of the 2:1 orbital resonance, we also point out several sequences
of chaotic events that can influence the Trojan population.


title: Inferring Company Structure from Limited Available Information

abstract:
  In this paper we present several algorithmic techniques for inferring the
structure of a company when only a limited amount of information is available.
We consider problems with two types of inputs: the number of pairs of employees
with a given property and restricted information about the hierarchical
structure of the company. We provide dynamic programming and greedy algorithms
for these problems.


title: Locating Restricted Facilities on Binary Maps

abstract:
  In this paper we consider several facility location problems with
applications to cost and social welfare optimization, when the area map is
encoded as a binary (0,1) mxn matrix. We present algorithmic solutions for all
the problems. Some cases are too particular to be used in practical situations,
but they are at least a starting point for more generic solutions.


title:
A new approach for the limit to tree height using a liquid nanolayer
  model

abstract:
  Liquids in contact with solids are submitted to intermolecular forces
inferring density gradients at the walls. The van der Waals forces make liquid
heterogeneous, the stress tensor is not any more spherical as in homogeneous
bulks and it is possible to obtain stable thin liquid films wetting vertical
walls up to altitudes that incompressible fluid models are not forecasting.
Application to micro tubes of xylem enables to understand why the ascent of sap
is possible for very high trees like sequoias or giant eucalyptus.


title:
Large time behavior of differential equations with drifted periodic
  coefficients modeling Carbon storage in soil

abstract:
  This paper is concerned with the linear ODE in the form
$y'(t)=\lambda\rho(t)y(t)+b(t)$, $\lambda <0$ which represents a simplified
storage model of the carbon in the soil. In the first part, we show that, for a
periodic function $\rho(t)$, a linear drift in the coefficient $b(t)$ involves
a linear drift for the solution of this ODE. In the second part, we extend the
previous results to a classical heat non-homogeneous equation. The connection
with an analytic semi-group associated to the ODE equation is considered in the
third part. Numerical examples are given.


title:
Unfolding the conical zones of the dissipation-induced subcritical
  flutter for the rotationally symmetrical gyroscopic systems

abstract:
  Flutter of an elastic body of revolution spinning about its axis of symmetry
is prohibited in the subcritical spinning speed range by the Krein theorem for
the Hamiltonian perturbations. Indefinite damping creates conical domains of
the subcritical flutter (subcritical parametric resonance) bifurcating into the
pockets of two Whitney's umbrellas when non-conservative positional forces are
additionally taken into account. This explains why in contrast to the common
intuition, but in agreement with experience, symmetry-breaking stiffness
variation can promote subcritical friction-induced oscillations of the rotor
rather than inhibit them.


title: Unconventional Bose-Einstein condensations from spin-orbit coupling

abstract:
  According to the "no-node" theorem, many-body ground state wavefunctions of
conventional Bose-Einstein condensations (BEC) are positive-definite, thus
time-reversal symmetry cannot be spontaneously broken. We find that
multi-component bosons with spin-orbit coupling provide an unconventional type
of BECs beyond this paradigm. We focus on the subtle case of isotropic Rashba
spin-orbit coupling and the spin-independent interaction. In the limit of the
weak confining potential, the condensate wavefunctions are frustrated at the
Hartree-Fock level due to the degeneracy of the Rashba ring. Quantum zero-point
energy selects the spin-spiral type condensate through the
"order-from-disorder" mechanism. In a strong harmonic confining trap, the
condensate spontaneously generates a half-quantum vortex combined with the
skyrmion type of spin texture. In both cases, time-reversal symmetry is
spontaneously broken. These phenomena can be realized in both cold atom systems
with artificial spin-orbit couplings generated from atom-laser interactions and
exciton condensates in semi-conductor systems.


title: Turduckening black holes: an analytical and computational study

abstract:
  We provide a detailed analysis of several aspects of the turduckening
technique for evolving black holes. At the analytical level we study the
constraint propagation for a general family of BSSN-type formulation of
Einstein's field equations and identify under what conditions the turducken
procedure is rigorously justified and under what conditions constraint
violations will propagate to the outside of the black holes. We present
high-resolution spherically symmetric studies which verify our analytical
predictions. Then we present three dimensional simulations of single distorted
black holes using different variations of the turduckening method and also the
puncture method. We study the effect that these different methods have on the
coordinate conditions, constraint violations, and extracted gravitational
waves. We find that the waves agree up to small but non-vanishing differences,
caused by escaping superluminal gauge modes. These differences become smaller
with increasing detector location.


title: Comparing Absolute and relative Gromov--Witten invariants

abstract:
  This note compares the usual (absolute) Gromov-Witten invariants of a
symplectic manifold with the invariants that count the curves relative to a
(symplectic) divisor D. We give explicit examples where these invariants differ
even though it seems at first that they should agree, for example when counting
genus zero curves in a class \be such that \be\cdot D=0. The main tool is the
decomposition formula in the form developed by A. Li--Ruan.


title:
The beryllium hollow-body solar sail: exploration of the Sun's
  gravitational focus and the inner Oort Cloud

abstract:
  Spacecraft kinematics, peak perihelion temperature and space environment
effects during solar-radiation-pressure acceleration for a beryllium
hollow-body interstellar solar sail inflated with hydrogen fill gas are
investigated. We demonstrate that diffusion is alleviated by an on-board fill
gas reserve and electrostatic pressure can be alleviated by increasing
perihelion distance. For a 0.1 AU perihelion, a 937 m radius sail with a sail
mass of 150 kg and a payload mass of 150 kg, perihelion sail temperature is
about 1000 K, peak acceleration is about 0.6 g, and solar-system exit velocity
is about 400 km/s. After sail deployments, the craft reaches the 200 AU
heliopause in 2.5 years, the Sun's inner gravitational focus at 550 AU in about
6.5 years and 2,550 AU in 30 years. The Be hollow-body sail could be applied in
the post 2040 time frame to verify general relativity predictions regarding the
Sun's inner gravitational focus and to explore particles and fields in the
Sun's inner Oort Comet Cloud.


title:
Quantum oscillations in graphene in the presence of disorder and
  interactions

abstract:
  Quantum oscillations in graphene is discussed. The effect of interactions are
addressed by Kohn's theorem regarding de Haas-van Alphen oscillations, which
states that electron-electron interactions cannot affect the oscillation
frequencies as long as disorder is neglected and the system is sufficiently
screened, which should be valid for chemical potentials not very close to the
Dirac point. We determine the positions of Landau levels in the presence of
potential disorder from exact transfer matrix and finite size diagonalization
calculations. The positions are shown to be unshifted even for moderate
disorder; stronger disorder, can, however, lead to shifts, but this also
appears minimal even for disorder width as large as one-half of the bare
hopping matrix element on the graphene lattice. Shubnikov-de Haas oscillations
of the conductivity are calculated analytically within a self-consistent Born
approximation of impurity scattering. The oscillatory part of the conductivity
follows the widely invoked Lifshitz-Kosevich form when certain mass and
frequency parameters are properly interpreted.


title: Using strong electromagnetic fields to control x-ray processes

abstract:
  Exploration of a new ultrafast-ultrasmall frontier in atomic and molecular
physics has begun. Not only is is possible to control outer-shell electron
dynamics with intense ultrafast optical lasers, but now control of inner-shell
processes has become possible by combining intense infrared/optical lasers with
tunable sources of x-ray radiation. This marriage of strong-field laser and
x-ray physics has led to the discovery of methods to control reversibly
resonant x-ray absorption in atoms and molecules on ultrafast timescales. Using
a strong optical dressing field, resonant x-ray absorption in atoms can be
markedly suppressed, yielding an example of electromagnetically induced
transparency for x rays. Resonant x-ray absorption can also be controlled in
molecules using strong non-resonant, polarized laser fields to align the
framework of a molecule, and therefore its unoccupied molecular orbitals to
which resonant absorption occurs. At higher laser intensities, ultrafast field
ionization produces an irreversible change in x-ray absorption. Finally, the
advent of x-ray free electron lasers enables first exploration of non-linear
x-ray processes.


title: Spatial Markov Semigroups Admit Hudson-Parthasarathy Dilations

abstract:
  This is the updated version of a preprint from September 2008. It presents,
for the first time, the result that (normal, strongly continuous) Markov
semigroups on $B(G)$ ($G$ a separable Hilbert space) admit a {\it
Hudson-Parthasarathy dilation} (that is, a dilation to a cocycle perturbation
of a {\it noise}) if and only the Markov semigroup is {\it spatial} (that is,
if it dominates an elementary CP-semigroup).
  The proof is by {\it general abstract nonsense} (taken from Arveson's
classification of $E_0$--semigroups on $B(H)$ by Arveson systems up to cocycle
conjugacy) and not, as usual, by constructing the cocycle as a solution of a
quantum stochastic differential equation in the sense of Hudson and
Parthasarathy.
  All other results that make similar statements (especially, Skeide [Ske16])
for more general $C^*$--algebras) have been proved later by suitable
adaptations of the methods exposed here. (They use Hilbert module techniques,
which we carefully avoid here in order to make the result available without any
appeal to Hilbert modules.)


title:
On the sum of the squared multiplicities of the distances in a point set
  over finite fields

abstract:
  We study a finite analog of a conjecture of Erd\"os on the sum of the squared
multiplicities of the distances determined by an $n$-element point set. Our
result is based on an estimate of the number of hinges in spectral graphs.


title:
A Note on the Equivalence of Gibbs Free Energy and Information Theoretic
  Capacity

abstract:
  The minimization of Gibbs free energy is based on the changes in work and
free energy that occur in a physical or chemical system. The maximization of
mutual information, the capacity, of a noisy channel is determined based on the
marginal probabilities and conditional entropies associated with a
communications system. As different as the procedures might first appear,
through the exploration of a simple, "dual use" Ising model, it is seen that
the two concepts are in fact the same. In particular, the case of a binary
symmetric channel is calculated in detail.


title: Labour Productivity Superstatistics

abstract:
  We discuss superstatistics theory of labour productivity. Productivity
distribution across workers, firms and industrial sectors are studied
empirically and found to obey power-distributions, in sharp contrast to the
equilibrium theories of mainstream economics. The Pareto index is found to
decrease with the level of aggregation, {\it i.e.}, from workers to firms and
to industrial sectors. In order to explain these phenomenological laws, we
propose a superstatistics framework, where the role of the fluctuating
temperature is played by the fluctuating demand.


title: A High Performance Memory Database for Web Application Caches

abstract:
  This paper presents the architecture and characteristics of a memory database
intended to be used as a cache engine for web applications. Primary goals of
this database are speed and efficiency while running on SMP systems with
several CPU cores (four and more). A secondary goal is the support for simple
metadata structures associated with cached data that can aid in efficient use
of the cache. Due to these goals, some data structures and algorithms normally
associated with this field of computing needed to be adapted to the new
environment.


title: Scattering in the adjoint sector of the c = 1 Matrix Model

abstract:
  Closed string tachyon emission from a traveling long string in Liouville
string theory is studied. The exact collective field Hamiltonian in the adjoint
sector of the c=1 matrix model is computed to capture the interaction between
the tip of the long string and the closed string tachyon field. The amplitude
for emission of a single tachyon quantum is obtained in a closed form using the
chiral formalism.


title: On the K-theory of truncated polynomial algebras over the integers

abstract:
  We show that the K_{2i}(Z[x]/(x^m),(x)) is finite of order (mi)!(i!)^{m-2}
and that K_{2i+1}(Z[x]/(x^m),(x)) is free abelian of rank m-1. This is
accomplished by showing that the equivariant homotopy groups of the topological
Hochschild spectrum THH(Z) are finite, in odd degrees, and free abelian, in
even degrees, and by evaluating their orders and ranks, respectively.


title: Light Charged and CP-odd Higgses in MSSM-like Models

abstract:
  We study the Higgs sector of supersymmetric models containing two Higgs
doublets with a light MSSM-like CP odd Higgs, $m_A \lesssim 10$ GeV, and $\tan
\beta \lesssim 2.5$. In this scenario all Higgses resulting from two Higgs
doublets: light and heavy CP even Higgses, $h$ and $H$, the CP odd Higgs, $A$,
and the charged Higgs, $H^\pm$, could have been produced at LEP or the
Tevatron, but would have escaped detection because they decay in modes that
have not been searched for or the experiments are not sensitive to. Especially
$H \to ZA$ and $H^\pm \to W^{\pm \star} A$ with $A \to c \bar c, \tau^+ \tau^-$
present an opportunity to discover some of the Higgses at LEP, the Tevatron and
also at B factories. In addition, the $2.8 \sigma$ excess of the branching
ratio $W \to \tau \nu$ with respect to the other leptons measured at LEP
correlates well with the existence of the charged Higgs with properties typical
for this scenario. Dominant $\tau$- and $c$-rich decay products of all Higgses
require modified strategies for their discovery at the LHC.


title: Universal Secure Network Coding via Rank-Metric Codes

abstract:
  The problem of securing a network coding communication system against an
eavesdropper adversary is considered. The network implements linear network
coding to deliver n packets from source to each receiver, and the adversary can
eavesdrop on \mu arbitrarily chosen links. The objective is to provide reliable
communication to all receivers, while guaranteeing that the source information
remains information-theoretically secure from the adversary. A coding scheme is
proposed that can achieve the maximum possible rate of n-\mu packets. The
scheme, which is based on rank-metric codes, has the distinctive property of
being universal: it can be applied on top of any communication network without
requiring knowledge of or any modifications on the underlying network code. The
only requirement of the scheme is that the packet length be at least n, which
is shown to be strictly necessary for universal communication at the maximum
rate. A further scenario is considered where the adversary is allowed not only
to eavesdrop but also to inject up to t erroneous packets into the network, and
the network may suffer from a rank deficiency of at most \rho. In this case,
the proposed scheme can be extended to achieve the rate of n-\rho-2t-\mu
packets. This rate is shown to be optimal under the assumption of zero-error
communication.


title: Non-uniform Braneworld Stars: an Exact Solution

abstract:
  The first exact interior solution to Einstein's field equations for a static
and non-uniform braneworld star with local and non-local bulk terms is
presented. It is shown that the bulk Weyl scalar ${\cal U}(r)$ is always
negative inside the stellar distribution, in consequence it reduces both the
effective density and the effective pressure. It is found that the anisotropy
generated by bulk gravity effect has an acceptable physical behaviour inside
the distribution. Using a Reissner-N\"{o}rdstrom-like exterior solution, the
effects of bulk gravity on pressure and density are found through matching
conditions.


title: An Approach Detecting the Event Horizon of Sgr A*

abstract:
  Imaging the vicinity of a black hole is one of the ultimate goals of VLBI
astronomy. The closest massive black hole, Sgr A*, located at the Galactic
center, is the leading candidate for such observations. Combined with recent
VLBI recording technique and submillimeter radio engineering, we now have
sufficient sensitivity for the observations. Here we show performance
simulations of submillimeter VLBI arrays for imaging Sgr A*. Good images are
obtained from submillimeter VLBI arrays in the southern hemisphere composed of
more than 10 stations. We also note that even with a small array, we can
estimate the shadow size and then the mass of the black hole from visibility
analysis. Now, all we need is to construct a submillimeter VLBI array in the
southern hemisphere if we wish to unveil the black hole environment of Sgr A*.
Key words: black hole, event horizon, Sgr A*, submillimeter


title: An inequality for Kruskal-Macaulay functions

abstract:
  Given integers $k\geq1$ and $n\geq0$, there is a unique way of writing $n$ as
$n=\binom{n_{k}}{k}+\binom{n_{k-1}}{k-1}+...+\binom{n_{1}}{1}$ so that $0\leq
n_{1}<...<n_{k-1}<n_{k}$. Using this representation, the \emph{Kruskal-Macaulay
function of}$n$ is defined as $\partial^{k}(n)
=\binom{n_{k}-1}{k-1}+\binom{n_{k-1}-1}{k-2}+...+\binom{n_{1}-1}% {0}.$ We show
that if $a\geq0$ and $a<\partial^{k+1}(n) $, then $\partial^{k}(a)
+\partial^{k+1}(n-a) \geq \partial^{k+1}(n) .$ As a corollary, we obtain a
short proof of Macaulay's Theorem. Other previously known results are obtained
as direct consequences.


title:
Presure-Induced Superconducting State of Antiferromagnetic
  CaFe$_2$As$_2$

abstract:
  The antiferromagnet CaFe$_2$As$_2$ does not become superconducting when
subject to ideal hydrostatic pressure conditions, where crystallographic and
magnetic states also are well defined. By measuring electrical resistivity and
magnetic susceptibility under quasi-hydrostatic pressure, however, we find that
a substantial volume fraction of the sample is superconducting in a narrow
pressure range where collapsed tetragonal and orthorhombic structures coexist.
At higher pressures, the collapsed tetragonal structure is stabilized, with the
boundary between this structure and the phase of coexisting structures strongly
dependent on pressure history. Fluctuations in magnetic degrees of freedom in
the phase of coexisting structures appear to be important for
superconductivity.


title: Non-perturbative construction of counterterms for 2PI-approximation

abstract:
  A concise method is presented for the non-perturbative computation of the
counterterms renormalising 2PI-actions. The procedure is presented for a real
scalar field up to lambda^2 order in the skeleton truncation of Gamma_2PI with
respect to the self-coupling, and in a constant symmetry breaking background.
The method is easily generalizable to field theories with arbitrary global
symmetry.


title:
Synthesis and characterization of chloride doped polyaniline by bulk
  oxidative chemical polymerization.Doping effect on electrical conductivity

abstract:
  Conductive polymers or "organic metals" are highly engineered nanostructured
materials made from organic building blocks. They are candidates as molecular
wires for nanotechnology applications in molecular electronics. The conduction
in these polymers is due to the presence of delocalized molecular orbitals. In
this work, we present the synthesis of chloride doped polyaniline by bulk
oxidative chemical polymerization using a solid aniline salt as a monomer
instead of liquid aniline to diminish toxic hazards. The FTIR and UV-visible
spectra confirmed the expected structure of the polymer. The electrical
conductivity measured using a four-probe method was 1.7 S/cm. The dependence of
impedance modulus on frequency was measured using an HP impedance analyzer in
the range 10 kHz-13 MHz. The influence of doping and the preparation
temperature on the electrical conductivity were also investigated.


title:
Solutions to 3-dimensional Navier-Stokes equations for incompressible
  fluid

abstract:
  This article is an updated version of the article that was published in the
Electronic Journal of Differential Equations on 10. July 2010. Two footnotes
have been added. One corrects a minor error not influencing the proof, the
second is only a clarifying text to the existing proof. A discussion how the
published article solves the Clay Millennium Prize problem on the Navier-Stokes
equations is added, the critizism against the published article is answered and
a discussion how the Clay problem statement should be corrected is included.
The article gives explicit solutions to the space-periodic Navier-Stokes
problem with non-periodic pressure. These type of solutions are not unique and
by using such solutions one can construct a periodic, smooth, divergence-free
initial vector field allowing a space-periodic and time-bounded external force
such that there exists a smooth solution to the 3-dimensional Navier-Stokes
equations for incompressible fluid with those initial conditions, but the
solution cannot be continued to the whole space.


title:
The Approximate Capacity of the Many-to-One and One-to-Many Gaussian
  Interference Channels

abstract:
  Recently, Etkin, Tse, and Wang found the capacity region of the two-user
Gaussian interference channel to within one bit/s/Hz. A natural goal is to
apply this approach to the Gaussian interference channel with an arbitrary
number of users. We make progress towards this goal by finding the capacity
region of the many-to-one and one-to-many Gaussian interference channels to
within a constant number of bits. The result makes use of a deterministic model
to provide insight into the Gaussian channel. The deterministic model makes
explicit the dimension of signal scale. A central theme emerges: the use of
lattice codes for alignment of interfering signals on the signal scale.


title: Electronic interlayer coupling in the LTT phase of La1.79Eu0.2Sr0.01CuO4

abstract:
  The electronic interlayer transport of the lightly doped antiferromagnet
La1.79Eu0.2Sr0.01CuO4 has been studied by means of magneto-resistance
measurements. The central problem addressed concerns the differences between
the electronic interlayer coupling in the tetragonal low-temperature (LTT)
phase and the orthorhombic low-temperature (LTO) phase. The key observation is
that the spin-flip induced drop in the c-axis magneto-resistance of the LTO
phase, which is characteristic for pure La2-xSrxCuO4, dramatically decreases in
the LTT phase. The results show that the transition from orthorhombic to
tetragonal symmetry and from collinear to non-collinear antiferromagnetic spin
structure eliminates the strain dependent anisotropic interlayer hopping as
well as the concomitant spin-valve type transport channel. Implications for the
stripe ordered LTT phase of La2-xBaxCuO4 are briefly discussed.


title: Phase statistics of seismic coda waves

abstract:
  We report the analysis of the statistics of the phase fluctuations in the
coda of earthquakes recorded during a temporary experiment deployed at Pinyon
Flats Observatory, California. The practical measurement of the phase is
discussed and the main pitfalls are underlined. For large values, the
experimental distributions of the phase first, second and third derivatives
obey universal power-law decays whose exponents are remarkably well predicted
by circular Gaussian statistics. For small values, these distributions are
flat. The details of the transition between the plateau and the power-law
behavior are governed by the wavelength. The correlation function of the first
phase derivative along the array shows a simple algebro-exponential decay with
the mean free path as the only length scale. Although only loose bounds are
provided in this study, our work suggests a new method to estimate the degree
of heterogeneity of the cr


title: Measurement of light mesons at RHIC by the PHENIX experiment

abstract:
  The PHENIX experiment at RHIC has measured a variety of light neutral mesons
($\pi^{0}$, K$_{S}^{0}$, $\eta$, $\omega$, $\eta^{\prime}$, $\phi$) via
multi-particle decay channels over a wide range of transverse momentum. A
review of the recent results on the production rates of light mesons in p+p and
their nuclear modification factors in d+Au, Cu+Cu and Au+Au collisions at
different energies is presented.


title:
Strong Lefschetz elements of the coinvariant rings of finite Coxeter
  groups

abstract:
  For the coinvariant rings of finite Coxeter groups of types other than H$_4$,
we show that a homogeneous element of degree one is a strong Lefschetz element
if and only if it is not fixed by any reflections. We also give the necessary
and sufficient condition for strong Lefschetz elements in the invariant
subrings of the coinvariant rings of Weyl groups.


title: The Suzaku Observations of SS Cygni in Quiescence and Outburst

abstract:
  We present results from the Suzaku observations of the dwarf nova SS Cyg in
quiescence and outburst in 2005 November. Owing to high sensitivity of the HXD
PIN detector and high spectral resolution of the XIS, we have determined
parameters of the plasma with unprecedented precision. The maximum temperature
of the plasma in quiescence 20.4 +4.0-2.6 (stat.) +/- 3.0 (sys.) keV is
significantly higher than that in outburst 6.0 +0.2-1.3 keV. The elemental
abundances are close to the solar ones for the medium-Z elements (Si, S, Ar)
whereas they decline both in lighter and heavier elements. Those of oxygen and
iron are 0.46 and 0.37 solar, respectively. That of carbon is exceptionally
high and 2 solar at least. The solid angle of the reflector subtending over the
optically thin thermal plasma is Omega/2\pi = 1.7+/-0.2 (stat.) +/-0.1 (sys.)
in quiescence. A 6.4 keV iron Ka line is resolved into a narrow and broad
components. These facts indicate that both the white dwarf and the accretion
disk contribute to the continuum reflection and the 6.4 keV iron Ka line. We
consider the standard optically thin boundary layer as the most plausible
picture for the plasma configuration in quiescence. The solid angle of the
reflector in outburst Omega/2\pi = 0.9 +0.5-0.4 and a broad 6.4 keV iron line
indicates that the reflection in outburst originates from the accretion disk
and an equatorial accretion belt. From the energy width of the 6.4 keV line, we
consider the optically thin thermal plasma in outburst as being distributed on
the accretion disk like solar coronae.


title:
From the Complete Yang Model to Snyder's Model, de Sitter Special
  Relativity and Their Duality

abstract:
  By means of Dirac procedure, we re-examine Yang's quantized space-time model,
its relation to Snyder's model, the de Sitter special relativity and their
UV-IR duality. Starting from a dimensionless dS_5-space in a 5+1-d Mink-space a
complete Yang model at both classical and quantum level can be presented and
there really exist Snyder's model, the dS special relativity and the duality.


title: Decay of Entanglement for Solid-State Qubits

abstract:
  We investigate the time evolution of entanglement under various models of
decoherence: A general heuristic model based on local relaxation and dephasing
times, and two microscopic models describing decoherence of electron spin
qubits in quantum dots due to the hyperfine interaction with the nuclei. For
each of the decoherence models, we investigate and compare how long the
entanglement can be detected. We also introduce filtered witness operators,
which extend the available detection time, and investigate this detection time
for various multipartite entangled states. By comparing the time required for
detection with the time required for generation and manipulation of
entanglement, we estimate for a range of different entangled states how many
qubits can be entangled in a one-dimensional array of electron spin qubits.


title: The Principle of Relativity and Special Relativity Triple

abstract:
  Based on the principle of relativity and the postulate on universal invariant
constants ($c,l$) as well as Einstein's isotropy conditions, three kinds of
special relativity form a triple with a common Lorentz group as isotropy group
under full Umov-Weyl-Fock-Lorentz transformations among inertial motions.


title:
Putting Yukawa-like Modified Gravity (MOG) on the test in the Solar
  System

abstract:
  We deal with a Yukawa-like long-range modified model of gravity (MOG) which
recently allowed to successfully accommodate many astrophysical and
cosmological features without resorting to dark matter. On Solar System scales
MOG predicts retrograde secular precessions of the planetary longitudes of the
perihelia \varpi whose existence has been put on the test here by taking the
ratios of the observationally estimated Pitjeva's corrections to the standard
Newtonian/Einsteinian perihelion precessions for different pairs of planets. It
turns out that MOG, in the present form which turned out to be
phenomenologically successful on astrophysical scales, is ruled out at more
than 3sigma level in the Solar System. If and when other teams of astronomers
will independently estimate their own extra-precessions of the perihelia it
will be possible to repeat such a test.


title: On the impact of the atmospheric drag on the LARES mission

abstract:
  The goal of the recently approved space-based LARES mission is to measure the
general relativistic Lense-Thirring effect in the gravitational field of the
spinning Earth at a repeatedly claimed 1% accuracy by combining its node Omega
with those of the existing LAGEOS and LAGEOS II laser-ranged satellites. In
this paper we show that, in view of the lower altitude of LARES (h=1450 km)
with respect to LAGEOS and LAGEOS II (h\approx 6000 km), the cross-coupling
between the effect of the atmospheric drag, both neutral and charged, on the
inclination of LARES and its classical node precession due to the Earth's
oblateness may induce a 3-9% year^-1 systematic bias on the total relativistic
precession. Since its extraction from the data will take about 5-10 years, such
a perturbing effect may degrade the total accuracy of the test, especially in
view of the large uncertainties in modeling the drag force.

categories: gr-qc astro-ph astro-ph.EP physics.geo-ph physics.space-ph


title: On fractionality of the path packing problem

abstract:
  In this paper, we study fractional multiflows in undirected graphs. A
fractional multiflow in a graph G with a node subset T, called terminals, is a
collection of weighted paths with ends in T such that the total weights of
paths traversing each edge does not exceed 1. Well-known fractional path
packing problem consists of maximizing the total weight of paths with ends in a
subset S of TxT over all fractional multiflows. Together, G,T and S form a
network. A network is an Eulerian network if all nodes in N\T have even
degrees.
  A term "fractionality" was defined for the fractional path packing problem by
A. Karzanov as the smallest natural number D so that there exists a solution to
the problem that becomes integer-valued when multiplied by D. A. Karzanov has
defined the class of Eulerian networks in terms of T and S, outside which D is
infinite and proved that whithin this class D can be 1,2 or 4. He conjectured
that D should be 1 or 2 for this class of networks. In this paper we prove this
conjecture.


title: Symmetries in Images on Ancient Seals

abstract:
  We discuss the presence of symmetries in images engraved on ancient seals, in
particular on stamp seals. Used to stamp decorations, to secure the containers
from tampering and for owner's identification, we can find seals that can be
dated from Neolithic times. Earliest seals were engraved with lines, dots and
spirals. Nevertheless, these very ancient stamp seals, in the small circular or
ovoid space of their bases, possess bilateral and rotational symmetries. The
shape of the base seems to determine the symmetries of images engraved on it.
We will also discuss what could be the meaning of antisymmetry and broken
symmetry for images on seals.


title: Quantized Conductance of a Single Magnetic Atom

abstract:
  A single Co atom adsorbed on Cu(111) or on ferromagnetic Co islands is
contacted with non-magnetic W or ferromagnetic Ni tips in a scanning tunneling
microscope. When the Co atom bridges two non-magnetic electrodes conductances
of 2e^2/h are found. With two ferromagnetic electrodes a conductance of e^2/h
is observed which may indicate fully spin-polarized transport.


title:
Infinitesimal rigidity of a compact hyperbolic 4-orbifold with totally
  geodesic boundary

abstract:
  Kerckhoff and Storm conjectured that compact hyperbolic n-orbifolds with
totally geodesic boundary are infinitesimally rigid when n>3. This paper
verifies this conjecture for a specific example based on the 4-dimensional
hyperbolic 120-cell.


title:
Quantum phase transition in the one-dimensional period-two and uniform
  compass model

abstract:
  Quantum phase transition in the one-dimensional period-two and uniform
quantum compass model are studied by using the pseudo-spin transformation
method and the trace map method. The exact solutions are presented, the
fidelity, the nearest-neighbor pseudo-spin entanglement, spin and pseudo-spin
correlation functions are then calculated. At the critical point, the fidelity
and its susceptibility change substantially, the gap of pseudo-spin concurrence
is observed, which scales as $1/N$ (N is system size). The spin correlation
functions show smooth behavior around the critical point. In the period-two
chain, the pseudo-spin correlation functions exhibit a oscillating behavior,
which is absent in the unform chain. The divergent correlation length at the
critical point is demonstrated in the general trend for both cases.


title: The Weak Field Limit of Higher Order Gravity

abstract:
  The Higher Order Theories of Gravity - $f(R, R_{\alpha\beta}R^{\alpha\beta})$
- theory, where $R$ is the Ricci scalar, $R_{\alpha\beta}$ is the Ricci tensor
and $f$ is any analytic function - have recently attracted a lot of interest as
alternative candidates to explain the observed cosmic acceleration, the
flatness of the rotation curves of spiral galaxies and other relevant
astrophysical phenomena. It is a crucial point testing these alternative
theories in the so called weak field and newtonian limit of a $f(R,
R_{\alpha\beta}R^{\alpha\beta})$ - theory. With this "perturbation technique"
it is possible to find spherically symmetric solutions and compare them with
the ones of General Relativity. On both approaches we found a modification of
General Relativity: the behaviour of gravitational potential presents a
modification Yukawa - like in the newtonian case and a massive propagation in
the weak field case. When the modification of the theory is removed (i.e. $f(R,
R_{\alpha\beta}R^{\alpha\beta}) = R$, Hilbert - Einstein lagrangian) we find
the usual outcomes of General Relativity. Also the Noether symmetries technique
has been investigated to find some time independent spherically symmetric
solutions.


title:
Evaluation of an Intelligent Assistive Technology for Voice Navigation
  of Spreadsheets

abstract:
  An integral part of spreadsheet auditing is navigation. For sufferers of
Repetitive Strain Injury who need to use voice recognition technology this
navigation can be highly problematic. To counter this the authors have
developed an intelligent voice navigation system, iVoice, which replicates
common spreadsheet auditing behaviours through simple voice commands. This
paper outlines the iVoice system and summarizes the results of a study to
evaluate iVoice when compared to a leading voice recognition technology.


title: Surgery in codimension 3 and the Browder--Livesay invariants

abstract:
  The inertia subgroup $I_n(\pi)$ of a surgery obstruction group $L_n(\pi)$ is
generated by elements which act trivially on the set of homotopy triangulations
$\Cal S(X)$ for some closed topological manifold $X^{n-1}$ with $\pi_1(X)=\pi$.
This group is a subgroup of the group $C_n(\pi)$ which consists of the elements
which can be realized by normal maps of closed manifolds. In all known cases
these groups coincide and the computation of them is one of the basic problems
of surgery theory. The computation of the group $C_n(\pi)$ is equivalent to the
computation the image of the assembly map $A:H_{n}(B\pi, \bold L_{\bullet})\to
L_{n}(\pi)$. Every Browder-Livesay filtration of the manifold $X$ provides a
collection of Browder-Livesay invariants which are the forbidden invariants in
the closed manifold surgery problem. In the present paper we describe all
possible forbidden invariants which can give a Browder-Livesay filtration for
computing the inertia subgroup. Our approach is a natural generalization of the
approach of Hambleton and Kharshiladze. More precisely, we prove that a
Browder-Livesay filtration of a given manifold can give the following forbidden
invariants for an element $x\in L_n(\pi_1(X))$ to belong to the subgroup
$I_n(\pi)$: the nontrivial Browder-Livesay invariants in codimensions 0, 1, 2
and a nontrivial class of obstructions of a restriction of a normal map to a
submanifold in codimension 3.


title: Fermion masses and mixing in models with SO(10) x A_4 symmetry

abstract:
  We study the flavour sector in models where the three families of matter are
unified in a $(16,3)$ representation of the $SO(10)\times A_4$ group. The
necessary ingredients to realize tri-bi-maximal mixing in the lepton sector are
identified systematically. The non-renormalizable operators contributing to the
fermion mass matrices play an important role. We also present a mechanism to
explain the inter-family mass hierarchy of quarks and charged leptons, which
relies on a `universal seesaw' mechanism and is compatible with tri-bi-maximal
mixing.


title:
Spreadsheet modelling for solving combinatorial problems: The vendor
  selection problem

abstract:
  Spreadsheets have grown up and became very powerful and easy to use tools in
applying analytical techniques for solving business problems. Operations
managers, production managers, planners and schedulers can work with them in
developing solid and practical Do-It-Yourself Decision Support Systems. Small
and Medium size organizations, can apply OR methodologies without the presence
of specialized software and trained personnel, which in many cases cannot
afford anyway. This paper examines an efficient approach in solving
combinatorial programming problems with the use of spreadsheets. A practical
application, which demonstrates the approach, concerns the development of a
spreadsheet-based DSS for the Multi Item Procurement Problem with Fixed Vendor
Cost. The DSS has been build using exclusively standard spreadsheet feature and
can solve real problems of substantial size. The benefits and limitations of
the approach are also discussed.


title: Abelian categories versus abelian 2-categories

abstract:
  Recently Dupont proved that the categories of discrete and codiscrete (or
connected) objects in an abelian 2-category are equivalent abelian categories.
He posses also a question whether any abelian category comes in this way. We
will give a rather trivial solution of this problem in the case when a given
abelian category has enough projective or injective objects.


title:
Comment on "Anomalies in electrostatic calibration for the measurement
  of the Casimir force in a sphere-plane geometry"

abstract:
  Recently W. J. Kim, M. Brown-Hayes, D. A. R. Dalvit, J. H. Brownell, and R.
Onofrio [Phys. Rev. A, v.78, 036102(R) (2008)] performed electrostatic
calibrations for a plane plate above a centimeter-size spherical lens at
separations down to 20-30 nm and observed "anomalous behavior". It was found
that the gradient of the electrostatic force does not depend on separation as
predicted on the basis of a pure Coulombian contribution. Some hypotheses which
could potentially explain the deviation from the expected behavior were
considered, and qualitative arguments in favor of the influence of patch
surface potentials were presented. We demonstrate that for the large lenses at
separations of a few tens nanometers from the plate, the electrostatic force
law used by the authors is not applicable due to possible deviations of the
mechanically polished and ground lens surface from a perfect spherical shape. A
model is proposed which explains the observed "anomalous behavior" using the
standard Coulombian force.


title: Dynamic tree algorithms

abstract:
  In this paper, a general tree algorithm processing a random flow of arrivals
is analyzed. Capetanakis--Tsybakov--Mikhailov's protocol in the context of
communication networks with random access is an example of such an algorithm.
In computer science, this corresponds to a trie structure with a dynamic input.
Mathematically, it is related to a stopped branching process with exogeneous
arrivals (immigration). Under quite general assumptions on the distribution of
the number of arrivals and on the branching procedure, it is shown that there
exists a positive constant $\lambda_c$ so that if the arrival rate is smaller
than $\lambda_c$, then the algorithm is stable under the flow of requests, that
is, that the total size of an associated tree is integrable. At the same time,
a gap in the earlier proofs of stability in the literature is fixed. When the
arrivals are Poisson, an explicit characterization of $\lambda_c$ is given.
Under the stability condition, the asymptotic behavior of the average size of a
tree starting with a large number of individuals is analyzed. The results are
obtained with the help of a probabilistic rewriting of the functional equations
describing the dynamics of the system. The proofs use extensively this
stochastic background throughout the paper. In this analysis, two basic limit
theorems play a key role: the renewal theorem and the convergence to
equilibrium of an auto-regressive process with a moving average.


title:
Development of conductometric biosensors based on alkaline phosphatases
  for the water quality control

abstract:
  Researches are focused on the elaboration of enzymatic microconductometric
device for heavy metal ions detection in water solutions. The manuscript
includes a general introduction, the first chapter contains bibliographic
review, the second chapter described the fundamentals of conductometric
transducers, the third chapter examining the possibility to create and to
optimize conductometric biosensor based on bovine alkaline phosphatase for
heavy metals ions detection, the fourth chapter devoted to creation and
optimization of conductometric biosensor based on alkaline phosphatase active
microalgae and sol gel technology, the last chapter described application of
the proposed algal biosensor for measurements of heavy metal ions toxicity of
waste water, general conclusions stating the progresses achieved in the field
of environmental monitoring


title:
Arithmetic gravity and Yang-Mills theory: An approach to adelic physics
  via algebraic spaces

abstract:
  This work is a dissertation thesis written at the WWU Muenster (Germany),
supervised by Prof. Dr. Raimar Wulkenhaar. We present an approach to adelic
physics based on the language of algebraic spaces. Relative algebraic spaces X
over a base S are considered as fundamental objects which describe space-time.
This yields a formulation of general relativity which is covariant with respect
to changes of the chosen domain of numbers S. With regard to adelic physics the
choice of S as an excellent Dedekind scheme is of interest (because this way
also the finite prime spots, i.e. the p-adic degrees of freedom are taken into
account). In this arithmetic case, it turns out that X is a Neron model. This
enables us to make concrete statements concerning the structure of the
space-time described by X. Furthermore, some solutions of the arithmetic
Einstein equations are presented. In a next step, Yang-Mills gauge fields are
incorporated.


title: Vulcanized Vortex

abstract:
  We investigate vortex configurations with the "vulcanization" term inspired
by the renormalization of $\phi_\star^4$ theory in the canonical
$\theta$-deformed noncommutativity. We focus on the classical limit of the
theory described by a single parameter which is the ratio of the vulcanization
and the noncommutativity parameters. We perform numerical calculations and find
that nontopological vortex solutions exist as well as Q-ball type solutions,
but topological vortex solutions are not admitted.


title: A class of Solvable Lie algebras

abstract:
  All finite-dimensional indecomposable solvable Lie algebras g, having the
filiform Lie algebra Q_(2m+1) as the nilradical, are studied and classified. It
turns out that the dimension of g is at most dimQ_(2m+1)+2.


title:
High-Tc Superconductivity in some Heavy Rare-earth Iron-arsenide
  REFeAsO1-delta(RE = Ho, Y, Dy and Tb) Compounds

abstract:
  New iron-arsenide superconductors of REFeAsO1-delta (RE = Ho, Y, Dy and Tb)
were successfully synthesized by a high pressure synthesizing method with a
special rapid quenching process, with the onset superconducting critical
temperatures at 50.3 K, 46.5 K, 52.2K and 48.5 K for RE = Ho, Y, Dy and Tb
respectively.


title:
Teleportation-Based Controlled-NOT Gate for Fault-Tolerant Quantum
  Computation

abstract:
  Quantum computers promise dramatic speed ups for many computational tasks.
For large-scale quantum computation however, the inevitable coupling of
physical qubits to the noisy environment imposes a major challenge for a
real-life implementation. A scheme introduced by Gottesmann and Chuang can help
to overcome this difficulty by performing universal quantum gates in a
fault-tolerant manner. Here, we report a non-trivial demonstration of this
architecture by performing a teleportation-based two-qubit controlled-NOT gate
through linear optics with a high-fidelity six-photon interferometer. The
obtained results clearly prove the involved working principles and the
entangling capability of the gate. Our experiment represents an important step
towards the feasibility of realistic quantum computers and could trigger many
further applications in linear optics quantum information processing.


title: Spreadsheet Components For All

abstract:
  We have prototyped a "spreadsheet component repository" Web site, from which
users can copy "components" into their own Excel or Google spreadsheets.
Components are collections of cells containing formulae: in real life, they
would do useful calculations that many practitioners find hard to program, and
would be rigorously tested and documented. Crucially, the user can tell the
repository which cells in their spreadsheet to use for a componen's inputs and
outputs. The repository will then reshape the component to fit. A single
component can therefore be used in many different sizes and shapes of
spreadsheet. We hope to set up a spreadsheet equivalent of the high-quality
numerical subroutine libraries that revolutionised scientific computing, but
where instead of subroutines, the library contains such components.


title:
Magnetic and phonon mechanisms of superconductivity in
  La$_{2-x}$Sr$_x$CuO$_4$ support each other

abstract:
  Strong electron correlations are responsible both for the insulator ground
state of undoped La$_2$CuO$_4$ and strong antiferromagnetic coupling $J$
between neighbouring spins. We consider magnetic mechanism of superconducting
pairing in the effective low energy $t - t' - t" - J^*$ model with all
parameters calculated {\it ab initio}. Interaction of strongly correlated
electrons with different phonon modes is also incorporated. In a BCS type
theory the $d_{x^2 - y^2}$ gap is given by a sum of magnetic and phonon
contributions. The phonon coupling parameter $\lambda = f(x)G$, where $G$ is a
combination of bare electron-phonon couplings for all modes and the function
$f$ depends on the hole concentration $x$ due to strong electron correlations.
The main contribution to the only fitting parameter $G$ is determined by a
competition of the breathing and buckling modes. Fitting the parameter $G$ from
the isotope effect we obtain that magnetic and phonon contributions to the
critical temperature $T_c $ work together and are of the same order of
magnitude.


title: A Primer on Spreadsheet Analytics

abstract:
  This paper provides guidance to an analyst who wants to extract insight from
a spreadsheet model. It discusses the terminology of spreadsheet analytics, how
to prepare a spreadsheet model for analysis, and a hierarchy of analytical
techniques. These techniques include sensitivity analysis, tornado charts,and
backsolving (or goal-seeking). This paper presents native-Excel approaches for
automating these techniques, and discusses add-ins that are even more
efficient. Spreadsheet optimization and spreadsheet Monte Carlo simulation are
briefly discussed. The paper concludes by calling for empirical research, and
describing desired features spreadsheet sensitivity analysis and spreadsheet
optimization add-ins.


title: Spreadsheet End-User Behaviour Analysis

abstract:
  To aid the development of spreadsheet debugging tools, a knowledge of
end-users natural behaviour within the Excel environment would be advantageous.
This paper details the design and application of a novel data acquisition tool,
which can be used for the unobtrusive recording of end-users mouse, keyboard
and Excel specific actions during the debugging of Excel spreadsheets. A
debugging experiment was conducted using this data acquisition tool, and based
on analysis of end-users performance and behaviour data, the authors developed
a "spreadsheet cell coverage feedback" debugging tool. Results from the
debugging experiment are presented in terms of enduser debugging performance
and behaviour, and the outcomes of an evaluation experiment with the debugging
tool are detailed.


title:
Splitting electrons into quasiparticles with fractional edge-state
  Mach-Zehnder interferometer

abstract:
  We have studied theoretically the tunneling between two edges of Quantum Hall
liquids (QHL) of different filling factors, $\nu_{0,1}=1/(2 m_{0,1}+1)$, with
$m_0 \geq m_1\geq 0$, through two separate point contacts in the geometry of
Mach-Zehnder interferometer [Y. Ji et al., Nature {\bf 422}, 415 (2003); I.
Neder et al., Phys.\ Rev.\ Lett. {\bf 96}, 016804 (2006)]. The quasi-particle
formulation of the interferometer model is derived as a dual to the initial
electron model, in the limit of strong electron tunneling reached at large
voltages or temperatures. For $m\equiv 1+m_{0}+m_{1}>1$, the tunneling of
quasiparticles of fractional charge $e/m$ leads to non-trivial $m$-state
dynamics of effective flux through the interferometer, which restores the
regular "electron" periodicity of the current in flux despite the fractional
charge and statistics of quasiparticles. The exact solution available for equal
times of propagation between the contacts along the two edges demonstrates that
the interference pattern of modulation of the tunneling current by flux depends
on voltage and temperature only through a common amplitude.


title:
Reconstruction of the Transmission Coefficient for Steplike Finite-Gap
  Backgrounds

abstract:
  We consider scattering theory for one-dimensional Jacobi operators with
respect to steplike quasi-periodic finite-gap backgrounds and show how the
transmission coefficient can be reconstructed from minimal scattering data.
This generalizes the Poisson-Jensen formula for the classical constant
background case.


title: Knizhnik-Zamolodchikov bundles are topologically trivial

abstract:
  We prove that the vector bundles at the core of the Knizhnik-Zamolodchikov
and quantum constructions of braid groups representations are topologically
trivial bundles. We provide partial generalizations of this result to
generalized braid groups. A crucial intermediate result is that the
representation ring of the symmetric group on n letters is generated by the
alternating powers of its natural n-dimensional representation.