title:
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor
  to the Aetiology of Vascular and Other Progressive Inflammatory and
  Degenerative Diseases

abstract:
  The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...


title:
Supersymmetry Signals of Supercritical String Cosmology at the Large
  Hadron Collider

abstract:
  We investigate the minimal supergravity (mSUGRA) signals at the LHC in the
context of supercritical string cosmology (SSC). In this theory, the presence
of a time dependent dilaton provides us with a smoothly evolving dark energy
and modifies the dark matter allowed region of the mSUGRA model with standard
cosmology. Such a dilaton dilutes the supersymmetric dark matter density (of
neutralinos) by a factor O(10) and consequently the regions with too much dark
matter in the standard scenario are allowed in the SSC. The final states
expected at the LHC in this scenario, unlike the standard scenario, consist of
Z bosons, Higgs bosons, and/or high energy taus. We show how to characterize
these final states and determine the model parameters. Using these parameters,
we determine the dark matter content and the neutralino-proton cross section.
All these techniques can also be applied to determine model parameters in SSC
models with different SUSY breaking scenarios.


title:
Gilbert Damping in Conducting Ferromagnets I: Kohn-Sham Theory and
  Atomic-Scale Inhomogeneity

abstract:
  We derive an approximate expression for the Gilbert damping coefficient
\alpha_G of itinerant electron ferromagnets which is based on their description
in terms of spin-density-functional-theory (SDFT) and Kohn-Sham quasiparticle
orbitals. We argue for an expression in which the coupling of magnetization
fluctuations to particle-hole transitions is weighted by the spin-dependent
part of the theory's exchange-correlation potential, a quantity which has large
spatial variations on an atomic length scale. Our SDFT result for \alpha_G is
closely related to the previously proposed spin-torque correlation-function
expression.


title:
The BCS-BEC crossover and superconductivity in a lattice fermion model
  with hard core repulsion

abstract:
  We have considered the BCS-BEC crossover at T=0 in the framework of a lattice
fermion model (the extended Hubbard model). We have analyzed the case of
on-site hard core repulsion ($U=\infty$) and intersite attraction ($W<0$) in a
3D system with extended s-wave pairing symmetry. The mechanisms of
density-driven and attraction-strength-driven crossover have been analyzed. We
have obtained the ground state phase diagram. The analyzed quantities are:
chemical potential, order parameter, coherence length and fraction of condensed
particles.


title: Failure Processes in Elastic Fiber Bundles

abstract:
  The fiber bundle model describes a collection of elastic fibers under load.
the fibers fail successively and for each failure, the load distribution among
the surviving fibers change. Even though very simple, the model captures the
essentials of failure processes in a large number of materials and settings. We
present here a review of fiber bundle model with different load redistribution
mechanism from the point of view of statistics and statistical physics rather
than materials science, with a focus on concepts such as criticality,
universality and fluctuations. We discuss the fiber bundle model as a tool for
understanding phenomena such as creep, and fatigue, how it is used to describe
the behavior of fiber reinforced composites as well as modelling e.g. network
failure, traffic jams and earthquake dynamics.


title: On surfaces of general type with maximal Albanese dimension

abstract:
  Given a minimal surface equipped with a generically finite map to an Abelian
variety, we give an optimal bound on the canonical degree of a rational or an
elliptic curve. As a corollary, we obtain the finiteness of rational and
elliptic curves on any surface of general type with two linearly independent
regular one forms.


title: Quantum frustration of dissipation by a spin bath

abstract:
  We investigate the evolution of a central spin coupled to a spin bath without
internal dynamics. We compare the cases where the bath couples to one or two
components of the spin. It is found that the central spin dynamics is enhanced
in the latter case, which may be interpreted as a frustration of dissipation.
However, the quantum purity of the spin decays fast in both scenarios. We
conclude that symmetric coupling of the bath to two orthogonal components of
the spin inhibits dissipation but not decoherence.


title:
A Novel Symbolic Type Neural Network Model- Application to River Flow
  Forecasting

abstract:
  In this paper we introduce a new symbolic type neural tree network called
symbolic function network (SFN) that is based on using elementary functions to
model systems in a symbolic form. The proposed formulation permits feature
selection, functional selection, and flexible structure. We applied this model
on the River Flow forecasting problem. The results found to be superior in both
fitness and sparsity.


title:
Measurements of Branching Fractions for B+ -> rho+ gamma, B0 -> rho0
  gamma, and B0 -> omega gamma

abstract:
  We present branching fraction measurements for the radiative decays B+ ->
rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma. The analysis is based on a
data sample of 465 million BBbar events collected with the BaBar detector at
the PEP-II asymmetric B factory. We find BR(B+ -> rho+ gamma) = (1.20 +0.42
-0.37 +/-0.20) x 10^-6, BR(B0 -> rho0 gamma) = (0.97 +0.24 -0.22 +/-0.06) x
10^-6, and a 90% C.L. upper limit BR(B0 -> omega gamma) < 0.9 x 10^-6, where
the first error is statistical and the second is systematic. We also measure
the isospin-violating quantities Gamma(B+ -> rho+ gamma) / 2Gamma(B0 -> rho0
gamma) - 1 = -0.43 +0.25 -0.22 +/-0.10.


title: Naturally Flavorful Supersymmetry at the LHC

abstract:
  The suppression of flavor and CP violation in supersymmetric theories may be
due to the mechanism responsible for the structure of the Yukawa couplings. We
study model independently the compatibility between low energy flavor and CP
constraints and observability of superparticles at the LHC, assuming a generic
correlation between the Yukawa couplings and the supersymmetry breaking
parameters. We find that the superpotential operators that generate scalar
trilinear interactions are generically problematic. We discuss several ways in
which this tension is naturally avoided. In particular, we focus on several
frameworks in which the dangerous operators are naturally absent. These
frameworks can be combined with many theories of flavor, including those with
(flat or warped) extra dimensions, strong dynamics, or flavor symmetries. We
show that the resulting theories can avoid all the low energy constraints while
keeping the superparticles light. The intergenerational mass splittings among
the sfermions can reflect the structure of the underlying flavor theory, and
can be large enough to be measurable at the LHC. Detailed observations of the
superparticle spectrum may thus provide new handles on the origin of the flavor
structure of the standard model.


title: Optical excitations in Sr$_{2}$CuO$_{3}$

abstract:
  We investigated excitation spectra of the one-dimensional chain compound
Sr$_{2}$CuO$_{3}$. The small peak at 2.3 eV in the loss function was turned to
correspond to the strong charge transfer transition at 1.8 eV in conductivity.
It has the excitonic character expected in one dimensional extended Hubbard
model of the transition from the lower Hubberd band to the Zhang-Rice singlet
state. The strongest peak at 2.7 eV in the loss function is attributed to the
continuum excitation of the excitonic charge transfer transition. The spectral
weight sum rule is satisfied within these transitions.


title:
Dynamics of interacting phantom scalar field dark energy in Loop Quantum
  Cosmology

abstract:
  We study the dynamics of a phantom scalar field dark energy interacting with
dark matter in loop quantum cosmology (LQC). Two kinds of coupling of the form
$\alpha{\rho_m}{\dot\phi}$ (case I) and $3\beta H (\rho_\phi +\rho_m)$ (case
II) between the phantom energy and dark matter are examined with the potential
for the phantom field taken to be exponential. For both kinds of interactions,
we find that the future singularity appearing in the standard FRW cosmology can
be avoided by loop quantum gravity effects. In case II, if the phantom field is
initially rolling down the potential, the loop quantum effect has no influence
on the cosmic late time evolution and the universe will accelerate forever with
a constant energy ratio between the dark energy and dark matter.


title: Single-Photon Molecular Cooling

abstract:
  We propose a general method to cool the translational motion of molecules.
Our method is an extension of single photon atomic cooling which was
successfully implemented in our laboratory. Requiring a single event of
absorption followed by a spontaneous emission, this method circumvents the need
for a cycling transition and can be applied to any paramagnetic or polar
molecule. In our approach, trapped molecules would be captured near their
classical turning points in an optical dipole or RF-trap following an
irreversible transition process.


title: Surface Plasma Waves Across the Layers of Intrinsic Josephson Junctions

abstract:
  We predict surface electromagnetic waves propagating across the layers of
intrinsic Josephson junctions. We find the spectrum of the surface waves and
study the distribution of the electromagnetic field inside and outside the
superconductor. The profile of the amplitude oscillations of the electric field
component of such waves is peculiar: initially, it increases toward the center
of the superconductor and, after reaching a crossover point, decreases
exponentially.


title: Quantum cryptography: theory and practice

abstract:
  A highly attenuated laser pulse which gives a weak coherent state is widely
used in quantum key distribution (QKD) experiments. A weak coherent state has
multi-photon components, which opens up a security loophole to the
sophisticated eavesdropper. With a small adjustment of the hardware, we prove
that the decoy state method can close this loophole and substantially improve
the QKD performance. We also propose a few practical decoy state protocols,
study statistical fluctuations and perform experimental demonstrations.
Moreover, we apply the methods from entanglement distillation protocols based
on two-way classical communication to improve the decoy state QKD performance.
Furthermore, we study the decoy state methods for other single photon sources,
such as triggering parametric down-conversion (PDC) source.
  We propose a model and post-processing scheme for the entanglement-based QKD
with a PDC source. Although the model is proposed to study the
entanglement-based QKD, we emphasize that our generic model may also be useful
for other non-QKD experiments involving a PDC source. By simulating a real PDC
experiment, we show that the entanglement-based QKD can achieve longer maximal
secure distance than the single-photon-based QKD schemes.
  We present a time-shift attack that exploits the efficiency mismatch of two
single photon detectors in a QKD system. This eavesdropping strategy can be
realized by current technology. We also discuss counter measures against the
attack and study the security of a QKD system with efficiency mismatch
detectors.


title: Flux-driven Josephson parametric amplifier

abstract:
  We have developed a Josephson parametric amplifier, comprising a
superconducting coplanar waveguide resonator terminated by a dc SQUID
(superconducting quantum interference device). An external field (the pump,
$\sim 20$ GHz) modulates the flux threading the dc SQUID, and, thereby, the
resonant frequency of the cavity field (the signal, $\sim 10$ GHz), which leads
to parametric signal amplification. We operated the amplifier at different band
centers, and observed amplification (17 dB at maximum) and deamplification
depending on the relative phase between the pump and the signal. The noise
temperature is estimated to be less than 0.87 K.


title: Hardy spaces of operator-valued analytic functions

abstract:
  We are concerned with Hardy and BMO spaces of operator-valued functions
analytic in the unit disk of $\mathbb{C}.$ In the case of the Hardy space, we
involve the atomic decomposition since the usual argument in the scalar setting
is not suitable. Several properties (the Garsia-norm equivalent theorem,
Carleson measure, and so on) of BMOA spaces are extended to the operator-valued
setting. Then, the operator-valued $\mathrm{H}^1$-BMOA duality theorem is
proved. Finally, by the $\mathrm{H}^1$-BMOA duality we present the Lusin area
integral and Littlewood-Paley $g$-function characterizations of the
operator-valued analytic Hardy space.


title:
Azimuthal Correlations with High-pT Multi-Hadron Cluster Triggers in
  Au+Au Collisions at sqrt(sNN) = 200 GeV

abstract:
  Di-hadron correlation measurements have been used to probe di-jet production
in collisions at RHIC. A strong suppression of the away-side high-pT yield in
these measurements is direct evidence that high-pT partons lose energy as they
traverse the strongly interacting medium. However, since the momentum of the
trigger particle is not a good measure of the jet energy, azimuthal di-hadron
correlations have limited sensitivity to the shape of the fragmentation
function. We explore the possibility to better constrain the initial parton
energy by using clusters of multiple high-pT hadrons in a narrow cone as the
'trigger particle' in the azimuthal correlation analysis. We present first
results from this analysis of multi-hadron triggered correlated yields in Au+Au
collisions at sqrt(sNN) = 200 GeV from STAR. The results are compared to Pythia
calculations, and the implications for energy loss and jet fragmentation are
discussed.


title: A Formalism for Quantum Games and an Application

abstract:
  This paper presents a new mathematical formalism that describes the
quantization of games. The study of so-called quantum games is quite new,
arising from a seminal paper of D. Meyer \cite{Meyer} published in Physics
Review Letters in 1999. The ensuing near decade has seen an explosion of
contributions and controversy over what exactly a quantized game really is and
if there is indeed anything new for game theory. What has clouded many of the
issues is the lack of a mathematical formalism for the subject in which these
various issues can be clearly and precisely expressed, and which provides a
context in which to present their resolution. Such a formalism is presented
here, along with proposed resolutions to some of the issues discussed in the
literature. One in particular, the question of whether there can exist
equilibria in a quantized version of a game that do not correspond to classical
correlated equilibria of that game and also deliver better payoffs than the
classical correlated equilibria is answered in the affirmative for the
Prisoner's Dilemma and Simplified Poker.


title: Heavy anion solvation of polarity fluctuations in Pnictides

abstract:
  Once again the condensed matter world has been surprised by the discovery of
yet another class of high temperature superconductors. The discovery of
iron-pnictide (FeAs) and chalcogenide (FeSe) based superconductors with a $T_c$
of up to 55 K is again evidence of how complex the many body problem really is,
or in another view how resourceful nature is. The first reactions would of
course be that these new materials must in some way be related to the
copper-oxide based superconductors for which a large number of theories exist
although a general consensus regarding the correct theory has not yet been
reached. Here we point out that the basic physical paradigm of the new iron
based superconductors is entirely different from the cuprates. Their
fundamental properties, structural and electronic, are dominated by the
exceptionally large pnictide polarizabilities.


title:
Octonionization of three player, two strategy maximally entangled
  quantum games

abstract:
  We develop an octonionic representation of the payoff function for three
player, two strategy, maximally entangled quantum games in order to obtain
computationally friendly version of this function. This computational
capability is then exploited to analyze and potentially classify the Nash
equilibria in the quantum games.


title: Quantum error correcting codes based on privacy amplification

abstract:
  Calderbank-Shor-Steane (CSS) quantum error-correcting codes are based on
pairs of classical codes which are mutually dual containing. Explicit
constructions of such codes for large blocklengths and with good error
correcting properties are not easy to find. In this paper we propose a
construction of CSS codes which combines a classical code with a two-universal
hash function. We show, using the results of Renner and Koenig, that the
communication rates of such codes approach the hashing bound on tensor powers
of Pauli channels in the limit of large block-length. While the bit-flip errors
can be decoded as efficiently as the classical code used, the problem of
efficiently decoding the phase-flip errors remains open.


title: Effective slip over superhydrophobic surfaces in thin channels

abstract:
  Superhydrophobic surfaces reduce drag by combining hydrophobicity and
roughness to trap gas bubbles in a micro- and nanoscopic texture. Recent work
has focused on specific cases, such as striped grooves or arrays of pillars,
with limited theoretical guidance. Here, we consider the experimentally
relevant limit of thin channels and obtain rigorous bounds on the effective
slip length for any two-component (e.g. low-slip and high-slip) texture with
given area fractions. Among all anisotropic textures, parallel stripes attain
the largest (or smallest) possible slip in a straight, thin channel for
parallel (or perpendicular) orientation with respect to the mean flow. For
isotropic (e.g. chessboard or random) textures, the Hashin-Strikman conditions
further constrain the effective slip. These results provide a framework for the
rational design of superhydrophobic surfaces.


title: Massive Gravity in Curved Cosmological Backgrounds

abstract:
  We study the physical propagating modes in a massive gravity model in curved
cosmological backgrounds, which we have found as classical solutions in our
previous paper. We show that, generically, there exist such the cosmological
background solutions consistent with the equations of motion where we assume
the ghost condensation ansatzes. Using the (1+3)-parametrization of the metric
fluctuations with 'unitary' gauge, we find that there is neither a scalar ghost
nor a tachyon in the spectrum of the propagating modes, the tensor modes become
massive owing to gravitational Higgs mechanism, and the model is free of the
Boulware-Deser instability. The price we have to pay is that the scalar sector
breaks the Lorentz-invariance, but there are no pathologies in the spectrum and
lead to interesting phenomenology. Moreover, we present a proof of the absence
of non-unitary modes for a specific ghost condensation model in a cosmological
background.


title: Algebraic topology from geometric viewpoint

abstract:
  This book is expository and is in Russian. It is shown how in the course of
solution of interesting geometric problems (close to applications) naturally
appear main notions of algebraic topology (homology groups, obstructions and
invariants, characteristic classes). Thus main ideas of algebraic topology are
presented with minimal technicalities. Familiarity of a reader with basic
notions of topology (such as 2-dimensional manifolds and vector fields) is
desirable, although definitions are given at the beginning. The book is
accessible to undergraduates and could also be an interesting easy reading for
professional mathematicians.


title:
Low frequency elastic wave propagation in 2D locally resonant phononic
  crystal with asymmetric resonator

abstract:
  The resonance modes and the related effects to the transmission of elastic
waves in a two dimensional phononic crystal formed by periodic arrangements of
a two blocks unit cell in one direction are studied. The unit cell consists of
two asymmetric elliptic cylinders coated with silicon rubber and embedded in a
rigid matrix. The modes are obtained by the semi-analytic method in the least
square collocation scheme and confirmed by the finite element method
simulations. Two resonance modes, corresponding to the vibration of the
cylinder along the long and short axes, give rise to resonance reflections of
elastic waves. One mode in between the two modes, related to the opposite
vibration of the two cylinders in the unit cell in the direction along the
layer, results in the total transmission of elastic waves due to zero effective
mass density at the frequency. The resonance frequency of this new mode changes
continuously with the orientation angle of the elliptic resonator.


title:
Characterization of integrated optics components for the second
  generation of VLTI instruments

abstract:
  Two of the three instruments proposed to ESO for the second generation
instrumentation of the VLTI would use integrated optics for beam combination.
Several design are studied, including co-axial and multi-axial recombination.
An extensive quantity of combiners are therefore under test in our
laboratories. We will present the various components, and the method used to
validate and compare the different combiners. Finally, we will discuss the
performances and their implication for both VSI and Gravity VLTI instruments.


title: Pesin-Type Identity for Weak Chaos

abstract:
  Pesin's identity provides a profound connection between entropy $h_{KS}$
(statistical mechanics) and the Lyapunov exponent $\lambda$ (chaos theory). It
is well known that many systems exhibit sub-exponential separation of nearby
trajectories and then $\lambda=0$. In many cases such systems are non-ergodic
and do not obey usual statistical mechanics. Here we investigate the
non-ergodic phase of the Pomeau-Manneville map where separation of nearby
trajectories follows $\delta x_t= \delta x_0 e^{\lambda_{\alpha} t^{\alpha}}$
with $0<\alpha<1$. The limit distribution of $\lambda_{\alpha}$ is the inverse
L{\'e}vy function. The average $< \lambda_{\alpha} >$ is related to the
infinite invariant density, and most importantly to entropy. Our work gives a
generalized Pesin's identity valid for systems with an infinite invariant
density.


title: Formation of guided spin-wave bullets in ferrimagnetic film stripes

abstract:
  The formation of quasi-2D nonlinear spin-wave eigenmodes in longitudinally
magnetized stripes of a ferrimagnetic film, so-called guided spin-wave bullets,
was experimentally observed by using time- and space-resolved Brillouin light
scattering spectroscopy and confirmed by numerical simulation. They represent
stable spin-wave packets propagating along a waveguide structure, for which
both transversal instability and interaction with the side edges of the
waveguide are important. The experiments and the numerical simulation of the
evolution of the spin-wave excitations show that the shape of the formed
packets and their behavior are strongly influenced by the confinement
conditions. The discovery of these modes demonstrates the existence of
quasi-stable nonlinear solutions in the transition regime between
one-dimensional and two-dimensional wave packet propagation.


title: A Class of Maximal-Rate, Low-PAPR, Non-square Complex Orthogonal Designs

abstract:
  Space-time block codes (STBCs) from non-square complex orthogonal designs are
bandwidth efficient when compared with those from square real/complex
orthogonal designs. Though there exists rate-1 ROD for any number of transmit
antennas, rate-1 complex orthogonal designs (COD) does not exist for more than
2 transmit antennas. Liang (IEEE Trans. Inform. Theory, 2003) and Lu et al
(IEEE Trans. Inform. Theory, 2005) have constructed a class of maximal rate
non-square CODs where the rate is ${1/2}+\frac{1}{n}$ if number of transmit
antennas $n$ is even and ${1/2}+\frac{1}{n+1}$ if $n$ is odd. In this paper, we
present a simple construction for maximal rate non-square CODs obtained from
square CODs which resembles the construction of rate-1 non-square RODs from
square RODs. These designs are shown to be amenable for construction of a class
of generalized CODs (called Coordinate-Interleaved Scaled CODs) with low
peak-to-average power ratio (PAPR) having the same parameters as the maximal
rate codes. Simulation results indicate that these codes perform better than
the existing maximal rate codes under peak power constraint while performing
the same under average power constraint.


title:
Coupled Painlev\'e VI systems in dimension four with affine Weyl group
  symmetry of type $E_6^{(2)}$

abstract:
  We find a four-parameter family of coupled Painlev\'e VI systems in dimension
four with affine Weyl group symmetry of type $E_6^{(2)}$. This is the first
example which gave higher order Painlev\'e type systems of type $E_{6}^{(2)}$.
We study its symmetry and holomorphy conditions.


title: A Counter Example To the Hodge Conjecture

abstract:
  In this paper, we give a simple counter example to the famous Hodge
conjecture.


title: Circle correspondence $C^*$-algebras

abstract:
  We investigate Cuntz-Pimsner $C^*$-algebras associated with certain
correspondences of the unit circle $\mathbb{T}$. We analyze these
$C^*$-algebras by analogy with irrational rotation algebras $A_\theta$ and
Cuntz algebras $\mathcal{O}_n$. We construct a Rieffel type projection, study
the fixed point algebras of certain actions of finite groups, and calculate the
entropy of a certain endomorphism. We also study the induced map of the dual
action of the gauge action on $K$-groups.


title: Weighted Semigroup Algebras as Dual Banach algebras

abstract:
  In this paper, among other things, we study those conditions under which the
weighted semigroup algebra $\ell^1(S,\omega)$ is a dual Banach algebra with
respect to predual $c_0(S)$. Some useful examples, illustrating the results,
are also included.


title: Manifestations of String Theory in Astrophysical Data and at the LHC

abstract:
  With the advent of the LHC and the continuing influx of cosmological data,
phenomenological aspects of string theory have received renewed attention in
recent years and many problems have been properly incorporated in this
framework. In this Dissertation, we suggest new string-related candidates for
the origin of dark energy and dark matter and propose ways of searching for
string resonances at the LHC.


title: Propagation and Ghosts in the Classical Kagome Antiferromagnet

abstract:
  We investigate the classical spin dynamics of the kagome antiferromagnet by
combining Monte Carlo and spin dynamics simulations. We show that this model
has two distinct low temperature dynamical regimes, both sustaining propagative
modes. The expected gauge invariance type of the low energy low temperature out
of plane excitations is also evidenced in the non linear regime. A detailed
analysis of the excitations allows to identify ghosts in the dynamical
structure factor, i.e propagating excitations with a strongly reduced spectral
weight. We argue that these dynamical extinction rules are of geometrical
origin.


title:
Simulations of the formation of a gaseous disc and young stars near Sgr
  A* via cloud-cloud collisions

abstract:
  Young massive stars in the central parsec of our Galaxy are best explained by
star formation within at least one, and possibly two, massive self-gravitating
gaseous discs. With help of numerical simulations, we here consider whether the
observed population of young stars could have originated from a large angle
collision of two massive gaseous clouds at R ~ 1 pc from Sgr A*. In all the
simulations performed, the post-collision gas flow forms an inner nearly
circular gaseous disc and one or two eccentric outer filaments, consistent with
the observations. Furthermore, the radial stellar mass distribution is always
very steep, sigma proportional to R^-2, again consistent with the data. The 3D
velocity structure of the stellar distribution is however sensitive to initial
conditions (e.g., the impact parameter of the clouds) and gas cooling details.
In all the cases the amount of gas accreted by our inner boundary condition is
large, enough to allow Sgr A* to radiate near its Eddington limit during ~ 10^5
years. This suggests that a refined model would have physically larger clouds
(or a cloud and a disc such as the CND) colliding at a distance of a few pc
rather than 1 pc as in our simulations.


title:
There are infinitely many prime numbers in all arithmetic progressions
  with first term and difference coprime

abstract:
  Dirichlet's proof of infinitely many primes in arithmetic progressions was
published in 1837, introduced L-series for the first time, and it is said to
have started rigorous analytic number theory. Dirichlet uses Euler's earlier
work on the zeta function and the distribution of primes. He first proves a
simpler case before going to full generality. The paper was translated from
German by R. Stephan and given a reference section.


title:
New Tests of Spatial Segregation Based on Nearest Neighbor Contingency
  Tables

abstract:
  The spatial clustering of points from two or more classes (or species) has
important implications in many fields and may cause the spatial patterns of
segregation and association, which are two major types of spatial interaction
between the classes. The null patterns we consider are random labeling (RL) and
complete spatial randomness (CSR) of points from two or more classes, which is
called CSR independence. The segregation and association patterns can be
studied using a nearest neighbor contingency table (NNCT) which is constructed
using the frequencies of nearest neighbor (NN) types in a contingency table.
Among NNCT-tests Pielou's test is liberal the null pattern but Dixon's test has
the desired significance level under the RL pattern. We propose three new
multivariate clustering tests based on NNCTs. We compare the finite sample
performance of these new tests with Pielou's and Dixon's tests and Cuzick &
Edward's k-NN tests in terms of empirical size under the null cases and
empirical power under various segregation and association alternatives and
provide guidelines for using the tests in practice. We demonstrate that the
newly proposed NNCT-tests perform relatively well compared to their competitors
and illustrate the tests using three example data sets. Furthermore, we compare
the NNCT-tests with the second-order methods using these examples.


title:
Image Steganography, a New Approach for Transferring Security
  Information

abstract:
  Steganography is the art of hiding the fact that communication is taking
place, by hiding information in other information. Many different carrier file
formats can be used, but digital images are the most popular because of their
frequency on the Internet. For hiding secret information in images, there
exists a large variety of steganographic techniques some are more complex than
others and all of them have respective strong and weak points. Different
applications have different requirements of the steganography technique used.
For example, some applications may require absolute invisibility of the secret
information, while others require a larger secret message to be hidden. This
paper intends to give an overview of image steganography, its uses and
techniques. It also attempts to identify the requirements of a good
steganographic algorithm and briefly reflects on which steganographic
techniques are more suitable for which applications.


title: Metastable superpositions of ortho- and para-Helium states

abstract:
  We analyze superpositions of ortho- and para-Helium states, considering the
possible existence of stationary and metastable states in the system. In
particular, the metastable superposition of 1s2s ortho and para states seems to
be accessible to experimental scrutiny.


title: Frames and Oversampling Formulas for Band Limited Functions

abstract:
  In this article we obtain families of frames for the space B_\omega of
functions with band in [-\omega,\omega] by using the theory of shift-invariant
spaces. Our results are based on the Gramian analysis of A. Ron and Z. Shen and
a variant, due to Bownik, of their characterization of families of functions
whose shifts form frames or Riesz bases. We give necessary and sufficient
conditions for the translates of a finite number of functions (generators) to
be a frame or a Riesz basis for B_\omega. We also give explicit formulas for
the dual generators and we apply them to Hilbert transform sampling and
derivative sampling. Finally, we provide numerical experiments which support
the theory.


title: The interface structure of epitaxial graphene grown on 4H-SiC(0001)

abstract:
  We present a structural analysis of the graphene-4HSiC(0001) interface using
surface x-ray reflectivity. We find that the interface is composed of an
extended reconstruction of two SiC bilayers. The interface directly below the
first graphene sheet is an extended layer that is more than twice the thickness
of a bulk SiC bilayer (~1.7A compared to 0.63A). The distance from this
interface layer to the first graphene sheet is much smaller than the graphite
interlayer spacing but larger than the same distance measured for graphene
grown on the (000-1) surface, as predicted previously by ab intio calculations.


title:
Spectroscopic and Photometric evidence of two stellar populations in the
  Galactic Globular Cluster NGC6121 (M4)

abstract:
  AIMS. We present abundance analysis based on high resolution spectra of 105
isolated red giant branch (RGB) stars in the Galactic Globular Cluster NGC 6121
(M4). Our aim is to study its star population in the context of the
multi-population phenomenon recently discovered to affect some Globular
Clusters. METHODS. The data have been collected with FLAMES+UVES, at the
ESO/VLT@UT2 telescope. Analysis was performed under LTE approximation for the
following elements: O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Ba, and NLTE
corrections were applied to Na and Mg. Spectroscopic data were coupled with
high-precision wide-field UBVI$_{\rm C}$ photometry from WFI@2.2m telescope and
infrared JHK photometry from 2MASS. RESULTS: We derived an average $\rm
{[Fe/H]}=-1.07\pm0.01$ (internal error), and an $\alpha$ enhancement of $\rm
{[\alpha/Fe]}=+0.39\pm0.05$ dex (internal error). We confirm the presence of an
extended Na-O anticorrelation, and find two distinct groups of stars with
significantly different Na and O content. We find no evidence of a Mg-Al
anticorrelation. By coupling our results with previous studies on the CN band
strength, we find that the CN strong stars have higher Na and Al content and
are more O depleted than the CN weak ones. The two groups of Na-rich, CN-strong
and Na-poor, CN-weak stars populate two different regions along the RGB. In the
$\rm {U}$ vs. $\rm {U-B}$ color magnitude diagram the RGB spread is present rom
the base of the RGB to the RGB-tip. Apparently, both spectroscopic and
photometric results imply the presence of two stellar populations in M4. We
briefly discuss the possible origin of these populations.


title:
On the potential catastrophic risk from metastable quantum-black holes
  produced at particle colliders

abstract:
  The question of whether collider produced of subnuclear black holes might
constitute a catastrophic risk is explored in a model of Casadio & Harms (2002)
that treats them as quantum-mechanical objects. A plausible scenario in which
these black holes accrete ambient matter at the Eddington limit shortly after
their production, thereby emitting Hawking radiation that would be harmful to
Earth and/or CERN and its surroundings, is described. Such black holes are
shown to remain undetectable in existing astrophysical observations and thus
evade a recent exclusion of risks from subnuclear black holes by Giddings &
Mangano (2008) and and a similar one by Koch et al. (2009). I further question
that these risk analyses are complete for the reason that they exclude
plausible black-hole parameter ranges from safety consideration without giving
any reason. Some feasible operational measures at colliders are proposed that
would allow the lowering of any remaining risk probability.
  Giddings & Mangano drew different general conclusions only because they made
different initial assumptions about the properties of microscopic black holes,
not because any of their technical conclusions are incorrect. A critical
comment by Giddings & Mangano (2008) on the present paper and a preprint by
Casadio et al.(2009) - that presents a treatment of the present issue with
methods and assumptions similar to mine - are addressed in appendices.


title: Model selection for density estimation with L2-loss

abstract:
  We consider here estimation of an unknown probability density s belonging to
L2(mu) where mu is a probability measure. We have at hand n i.i.d. observations
with density s and use the squared L2-norm as our loss function. The purpose of
this paper is to provide an abstract but completely general method for
estimating s by model selection, allowing to handle arbitrary families of
finite-dimensional (possibly non-linear) models and any density s belonging to
L2(mu). We shall, in particular, consider the cases of unbounded densities and
bounded densities with unknown bound and investigate how the L-infinity-norm of
s may influence the risk. We shall also provide applications to adaptive
estimation and aggregation of preliminary estimators. Although of a purely
theoretical nature, our method leads to results that cannot presently be
reached by more concrete methods.


title: The finite harmonic oscillator and its associated sequences

abstract:
  A system of functions (signals) on the finite line, called the oscillator
system, is described and studied. Applications of this system for discrete
radar and digital communication theory are explained.
  Keywords: Weil representation, commutative subgroups, eigenfunctions, random
behavior, deterministic construction

categories: cs.IT cs.CR cs.DM math-ph math.GR math.IT math.MP math.NT math.PR math.QA math.RT math.SG quant-ph


title:
Comprehensive quantum Monte Carlo study of the quantum critical points
  in planar dimerized/quadrumerized Heisenberg models

abstract:
  We study two planar square lattice Heisenberg models with explicit
dimerization or quadrumerization of the couplings in the form of ladder and
plaquette arrangements. We investigate the quantum critical points of those
models by means of (stochastic series expansion) quantum Monte Carlo
simulations as a function of the coupling ratio $\alpha = J^\prime/J$. The
critical point of the order-disorder quantum phase transition in the ladder
model is determined as $\alpha_\mathrm{c} = 1.9096(2)$ improving on previous
studies. For the plaquette model we obtain $\alpha_\mathrm{c} = 1.8230(2)$
establishing a first benchmark for this model from quantum Monte Carlo
simulations. Based on those values we give further convincing evidence that the
models are in the three-dimensional (3D) classical Heisenberg universality
class. The results of this contribution shall be useful as references for
future investigations on planar Heisenberg models such as concerning the
influence of non-magnetic impurities at the quantum critical point.


title: Gerbe-holonomy for surfaces with defect networks

abstract:
  We define the sigma-model action for world-sheets with embedded defect
networks in the presence of a three-form field strength. We derive the defect
gluing condition for the sigma-model fields and their derivatives, and use it
to distinguish between conformal and topological defects. As an example, we
treat the WZW model with defects labelled by elements of the centre Z(G) of the
target Lie group G; comparing the holonomy for different defect networks gives
rise to a 3-cocycle on Z(G). Next, we describe the factorisation properties of
two-dimensional quantum field theories in the presence of defects and compare
the correlators for different defect networks in the quantum WZW model. This,
again, results in a 3-cocycle on Z(G). We observe that the cocycles obtained in
the classical and in the quantum computation are cohomologous.


title:
59-Co and 75-As NMR Investigation of Electron-Doped High Tc
  Superconductor BaFe(1.8)Co(0.2)As(2) (Tc = 22K)

abstract:
  We report an NMR investigation of the superconductivity in BaFe(2)As(2)
induced by Co doping (Tc=22K). We demonstrate that Co atoms form an alloy with
Fe atoms and donate carriers without creating localized moments. Our finding
strongly suggests that the underlying physics of iron-pnictide superconductors
is quite different from the widely accepted physical picture of high Tc
cuprates as doped Mott insulators. We also show a crossover of electronic
properties into a low temperature pseudo-gap phase with a pseudo-gap Delta
560K, where chi(spin) constant and resisitivty T. The NMR Knight shift below Tc
decreases for both along the c-axis and ab-plane, and is consistent with the
singlet pairing scenario.


title: All-particle primary energy spectrum in the 3-200 PeV energy range

abstract:
  We present all-particle primary cosmic-ray energy spectrum in the 3-200 PeV
energy range obtained by a multi-parametric event-by-event evaluation of the
primary energy. The results are obtained on the basis of an expanded EAS data
set detected at mountain level (700 g/cm^2) by the GAMMA experiment. The energy
evaluation method has been developed using the EAS simulation with the SIBYLL
interaction model taking into account the response of GAMMA detectors and
reconstruction uncertainties of EAS parameters. Nearly unbiased (<5%) energy
estimations regardless of a primary nuclear mass with an accuracy of about
15-10% in the 3-200 PeV energy range respectively are attained. An irregularity
('bump') in the spectrum is observed at primary energies of ~74 PeV. This bump
exceeds a smooth power-law fit to the data by about 4 standard deviations. Not
rejecting stochastic nature of the bump completely, we examined the systematic
uncertainties of our methods and conclude that they cannot be responsible for
the observed feature.


title: Maslov class rigidity for Lagrangian submanifolds via Hofer's geometry

abstract:
  In this work, we establish new rigidity results for the Maslov class of
Lagrangian submanifolds in large classes of closed and convex symplectic
manifolds. Our main result establishes upper bounds for the minimal Maslov
number of displaceable Lagrangian submanifolds which are product manifolds
whose factors each admit a metric of negative sectional curvature. Such
Lagrangian submanifolds exist in every symplectic manifold of dimension greater
than six or equal to four.
  The proof utilizes the relations between closed geodesics on the Lagrangian,
the periodic orbits of geometric Hamiltonian flows supported near the
Lagrangian, and the length minimizing properties of these flows with respect to
the negative Hofer length functional.


title: Large-scale magnetic topologies of mid-M dwarfs

abstract:
  We present in this paper the first results of a spectropolarimetric analysis
of a small sample (~ 20) of active stars ranging from spectral type M0 to M8,
which are either fully-convective or possess a very small radiative core. This
study aims at providing new constraints on dynamo processes in fully-convective
stars.
  The present paper focuses on 5 stars of spectral type ~M4, i.e. with masses
close to the full convection threshold (~ 0.35 Msun), and with short rotational
periods. Tomographic imaging techniques allow us to reconstruct the surface
magnetic topologies from the rotationally modulated time-series of circularly
polarised profiles. We fnd that all stars host mainly axisymmetric large-scale
poloidal fields. Three stars were observed at two different epochs separated by
~1 yr; we find the magnetic topologies to be globally stable on this timescale.
  We also provide an accurate estimation of the rotational period of all stars,
thus allowing us to start studying how rotation impacts the large-scale
magnetic field.


title: Holographic Dark Energy Model and Scalar-Tensor Theories

abstract:
  We study the holographic dark energy model in a generalized scalar tensor
theory. In a universe filled with cold dark matter and dark energy, the effect
of potential of the scalar field is investigated in the equation of state
parameter. We show that for a various types of potentials, the equation of
state parameter is negative and transition from deceleration to acceleration
expansion of the universe is possible.


title:
Superconductivity coexisting with phase-separated static magnetic order
  in (Ba,K)Fe$_{2}$As$_{2}$, (Sr,Na)Fe$_{2}$As$_{2}$ and CaFe$_{2}$As$_{2}$

abstract:
  The recent discovery and subsequent developments of FeAs-based
superconductors have presented novel challenges and opportunities in the quest
for superconducting mechanisms in correlated-electron systems. Central issues
of ongoing studies include interplay between superconductivity and magnetism as
well as the nature of the pairing symmetry reflected in the superconducting
energy gap. In the cuprate and RE(O,F)FeAs (RE = rare earth) systems, the
superconducting phase appears without being accompanied by static magnetic
order, except for narrow phase-separated regions at the border of phase
boundaries. By muon spin relaxation measurements on single crystal specimens,
here we show that superconductivity in the AFe$_{2}$As$_{2}$ (A = Ca,Ba,Sr)
systems, in both the cases of composition and pressure tunings, coexists with a
strong static magnetic order in a partial volume fraction. The superfluid
response from the remaining paramagnetic volume fraction of
(Ba$_{0.5}$K$_{0.5}$)Fe$_{2}$As$_{2}$ exhibits a nearly linear variation in T
at low temperatures, suggesting an anisotropic energy gap with line nodes
and/or multi-gap effects.


title:
Topological quantum phase transitions of ultracold fermions in optical
  lattices

abstract:
  We consider the possibility of topological quantum phase transitions of
ultracold fermions in optical lattices, which can be studied as a function of
interaction strength or atomic filling factor (density). The phase transitions
are connected to the topology of the elementary excitation spectrum, and occur
only for non-zero angular momentum pairing (p-wave, d-wave and f-wave), while
they are absent for s-wave. We construct phase diagrams for the specific
example of highly anisotropic optical lattices, where the proposed topological
phase transitions are most pronounced. To characterize the existence of these
topological transitions, we calculate several measurable quantities including
momentum distribution, quasi-particle excitation spectrum, atomic
compressibility, superfluid density, and sound velocities.


title: Determining sets, resolving sets, and the exchange property

abstract:
  A subset U of vertices of a graph G is called a determining set if every
automorphism of G is uniquely determined by its action on the vertices of U. A
subset W is called a resolving set if every vertex in G is uniquely determined
by its distances to the vertices of W. Determining (resolving) sets are said to
have the exchange property in G if whenever S and R are minimal determining
(resolving) sets for G and r\in R, then there exists s\in S so that S-\{s\}\cup
\{r\} is a minimal determining (resolving) set. This work examines graph
families in which these sets do, or do not, have the exchange property. This
paper shows that neither determining sets nor resolving sets have the exchange
property in all graphs, but that both have the exchange property in trees. It
also gives an infinite graph family (n-wheels where n\geq 8) in which
determining sets have the exchange property but resolving sets do not. Further,
this paper provides necessary and sufficient conditions for determining sets to
have the exchange property in an outerplanar graph.


title:
The electric dipole moment of the nucleon from simulations at imaginary
  vacuum angle theta

abstract:
  We compute the electric dipole moment of proton and neutron from lattice QCD
simulations with N_f=2 flavors of dynamical quarks at imaginary vacuum angle
theta. The calculation proceeds via the CP odd form factor F_3. A novel feature
of our calculation is that we use partially twisted boundary conditions to
extract F_3 at zero momentum transfer. As a byproduct, we test the QCD vacuum
at nonvanishing theta.


title: Cerny's conjecture, synchronizing automata, group representation theory

abstract:
  Let us say that a Cayley graph $\Gamma$ of a group $G$ of order $n$ is a
Cerny Cayley graph if every synchronizing automaton containing $\Gamma$ as a
subgraph with the same vertex set admits a synchronizing word of length at most
$(n-1)^2$. In this paper we use the representation theory of groups over the
rational numbers to obtain a number of new infinite families of {\v{C}}ern{\'y}
Cayley graphs.


title: The cyclic sliding operation in Garside groups

abstract:
  We present a new operation to be performed on elements in a Garside group,
called cyclic sliding, which is introduced to replace the well known cycling
and decycling operations. Cyclic sliding appears to be a more natural choice,
simplifying the algorithms concerning conjugacy in Garside groups and having
nicer theoretical properties. We show, in particular, that if a super summit
element has conjugates which are 'rigid' (that is, which have a certain
particularly simple structure), then the optimal way of obtaining such a rigid
conjugate through conjugation by positive elements is given by iterated cyclic
sliding.


title:
A General Theory of Computational Scalability Based on Rational
  Functions

abstract:
  The universal scalability law of computational capacity is a rational
function C_p = P(p)/Q(p) with P(p) a linear polynomial and Q(p) a second-degree
polynomial in the number of physical processors p, that has been long used for
statistical modeling and prediction of computer system performance. We prove
that C_p is equivalent to the synchronous throughput bound for a
machine-repairman with state-dependent service rate. Simpler rational
functions, such as Amdahl's law and Gustafson speedup, are corollaries of this
queue-theoretic bound. C_p is further shown to be both necessary and sufficient
for modeling all practical characteristics of computational scalability.


title: Derivatives of Knots and Second-order Signatures

abstract:
  We define a set of "second-order" L^(2)-signature invariants for any
algebraically slice knot. These obstruct a knot's being a slice knot and
generalize Casson-Gordon invariants, which we consider to be "first-order
signatures". As one application we prove: If K is a genus one slice knot then,
on any genus one Seifert surface, there exists a homologically essential simple
closed curve of self-linking zero, which has vanishing zero-th order signature
and a vanishing first-order signature. This extends theorems of Cooper and
Gilmer. We introduce a geometric notion, that of a derivative of a knot with
respect to a metabolizer. We also introduce a new equivalence relation,
generalizing homology cobordism, called null-bordism.


title: Cut-wire-pair structures as two-dimensional magnetic metamaterials

abstract:
  We study numerically and experimentally magnetic metamaterials based on
cut-wire pairs instead of split-ring resonators. The cut-wire pair planar
structure is extended in order to create a truly two-dimensional metamaterial
suitable for scaling to optical frequencies. We fabricate the cut-wire
metamaterial operating at microwave frequencies with lattice spacing around 10%
of the free-space wavelength, and find good agreement with direct numerical
simulations. Unlike the structures based on split-ring resonators, the
nearest-neighbor coupling in cut-wire pairs can result in a magnetic stop-band
with propagation in the transverse direction.


title: Asymptotic upper bounds on the shades of t-intersecting families

abstract:
  We examine the m-shades of t-intersecting families of k-subsets of [n], and
conjecture on the optimal upper bound on their cardinalities. This conjecture
extends Frankl's General Conjecture that was proven true by
Ahlswede-Khachatrian. From this we deduce the precise asymptotic upper bounds
on the cardinalities of m-shades of t(m)-intersecting families of k(m)-subsets
of [2m], as m -> infinity. A generalization to cross-t-intersecting families is
also considered.


title: A Reflection Principle for Three Vicious Walkers

abstract:
  We establish a reflection principle for three lattice walkers and use this
principle to reduce the enumeration of the configurations of three vicious
walkers to that of configurations of two vicious walkers. In the combinatorial
treatment of two vicious walkers, we make connections to two-chain watermelons
and to the classical ballot problem. Precisely, the reflection principle leads
to a bijection between three walks $(L_1, L_2, L_3)$ such that $L_2$ intersects
both $L_1$ and $L_3$ and three walks $(L_1, L_2, L_3)$ such that $L_1$
intersects $L_3$. Hence we find a combinatorial interpretation of the formula
for the generating function for the number of configurations of three vicious
walkers, originally derived by Bousquet-M\'elou by using the kernel method, and
independently by Gessel by using tableaux and symmetric functions.


title: The Asymmetric Superfluid Local Density Approximation (ASLDA)

abstract:
  Here we describe the form of the Asymmetric Superfluid Local Density
Approximation (ASLDA), a Density Functional Theory (DFT) used to model the
two-component unitary Fermi gas. We give the rational behind the functional,
and describe explicitly how we determine the form of the DFT from the to the
available numerical and experimental data.


title: Neutrino nucleus cross sections

abstract:
  We present the results of our calculation which has been performed to study
the nuclear effects in the quasielastic, inelastic and deep inelastic
scattering of neutrinos(antineutrinos) from nuclear targets. These calculations
are done in the local density approximation. We take into account the effect of
Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak
transition strengths in the nuclear medium in the case of the quasielastic
reaction. The inelastic reaction leading to production of pions is calculated
in a $\Delta $- dominance model taking into account the renormalization of
$\Delta$ properties in the nuclear medium and the final state interaction
effects of the outgoing pions with the residual nucleus. We discuss the nuclear
effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic
neutrino(antineutrino) reaction using a relativistic framework to describe the
nucleon spectral function in the nucleus.


title: L-functions for GSp(4)xGL(2)in the case of high GL(2) conductor

abstract:
  Furusawa has given an integral representation for the degree 8 L-function of
GSp(4) x GL(2) and has carried out the unramified calculation. The local p-adic
zeta integrals were calculated in our earlier work under the assumption that
the GSp(4) representation \pi is unramified and the GL(2) representation \tau
has conductor p. In the present work we generalize to the case where the GL(2)
representation has arbitrarily high conductor. The result is that the zeta
integral represents the local Euler factor L(s,\pi \times \tau) in all cases.
As a global application we obtain a special value result for a GSp(4) x GL(2)
global L-function coming from classical holomorphic cusp forms with arbitrarily
high level for the elliptic modular form.


title: Gas disks to gas giants: Simulating the birth of planetary systems

abstract:
  The ensemble of now more than 250 discovered planetary systems displays a
wide range of masses, orbits and, in multiple systems, dynamical interactions.
These represent the end point of a complex sequence of events, wherein an
entire protostellar disk converts itself into a small number of planetary
bodies. Here, we present self-consistent numerical simulations of this process,
which produce results in agreement with some of the key trends observed in the
properties of the exoplanets. Analogs to our own solar system do not appear to
be common, originating from disks near the boundary between barren and (giant)
planet-forming.


title: Characterizing the Hofstadter butterfly's outline with Chern numbers

abstract:
  In this work, we report original properties inherent to independent particles
subjected to a magnetic field by emphasizing the existence of regular
structures in the energy spectrum's outline. We show that this fractal curve,
the well-known Hofstadter butterfly's outline, is associated to a specific
sequence of Chern numbers that correspond to the quantized transverse
conductivity. Indeed the topological invariant that characterizes the
fundamental energy band depicts successive stairways as the magnetic flux
varies. Moreover each stairway is shown to be labeled by another Chern number
which measures the charge transported under displacement of the periodic
potential. We put forward the universal character of these properties by
comparing the results obtained for the square and the honeycomb geometries.


title:
Injection of Short-Lived Radionuclides into the Early Solar System from
  a Faint Supernova with Mixing-Fallback

abstract:
  Several short-lived radionuclides (SLRs) were present in the early solar
system, some of which should have formed just prior to or soon after the solar
system formation. Stellar nucleosynthesis has been proposed as the mechanism
for production of SLRs in the solar system, but no appropriate stellar source
has been found to explain the abundances of all solar system SLRs.
  In this study, we propose a faint supernova with mixing and fallback as a
stellar source of SLRs with mean lives of <5 Myr (26Al, 41Ca, 53Mn, and 60Fe)
in the solar system. In such a supernova, the inner region of the exploding
star experiences mixing, a small fraction of mixed materials is ejected, and
the rest undergoes fallback onto the core. The modeled SLR abundances agree
well with their solar system abundances if mixing-fallback occurs within the
C/O-burning layer. In some cases, the initial solar system abundances of the
SLRs can be reproduced within a factor of 2. The dilution factor of supernova
ejecta to the solar system materials is ~10E-4 and the time interval between
the supernova explosion and the formation of oldest solid materials in the
solar system is ~1 Myr. If the dilution occurred due to spherically symmetric
expansion, a faint supernova should have occurred nearby the solar system
forming region in a star cluster.


title: SO(3)-Donaldson invariants of CP^2 and Mock Theta Functions

abstract:
  We compute the Moore-Witten regularized u-plane integral on CP^2, and we
confirm their conjecture that it is the generating function for the
SO(3)-Donaldson invariants of CP^2. We prove this conjecture using the theory
of mock theta functions and harmonic Maass forms. We also derive further such
generating functions for the SO(3)-Donaldson invariants with 2N_f massless
monopoles using the geometry of certain rational elliptic surfaces
(N_f=0,2,3,4). We show that the partition function for N_f=4 is nearly modular.
When combined with one of Ramanujan's mock theta functions, we obtain a weight
1/2 modular form. This fact is central to the proof of the conjecture.


title:
Links between traumatic brain injury and ballistic pressure waves
  originating in the thoracic cavity and extremities

abstract:
  Identifying patients at risk of traumatic brain injury (TBI) is important
because research suggests prophylactic treatments to reduce risk of long-term
sequelae. Blast pressure waves can cause TBI without penetrating wounds or
blunt force trauma. Similarly, bullet impacts distant from the brain can
produce pressure waves sufficient to cause mild to moderate TBI. The fluid
percussion model of TBI shows that pressure impulses of 15-30 psi cause mild to
moderate TBI in laboratory animals. In pigs and dogs, bullet impacts to the
thigh produce pressure waves in the brain of 18-45 psi and measurable injury to
neurons and neuroglia. Analyses of research in goats and epidemiological data
from shooting events involving humans show high correlations (r > 0.9) between
rapid incapacitation and pressure wave magnitude in the thoracic cavity. A case
study has documented epilepsy resulting from a pressure wave without the bullet
directly hitting the brain. Taken together, these results support the
hypothesis that bullet impacts distant from the brain produce pressure waves
that travel to the brain and can retain sufficient magnitude to induce brain
injury. The link to long-term sequelae could be investigated via
epidemiological studies of patients who were gunshot in the chest to determine
whether they experience elevated rates of epilepsy and other neurological
sequelae.


title:
Loewner equations, Hirota equations and reductions of universal Whitham
  hierarchy

abstract:
  This paper reconsiders finite variable reductions of the universal Whitham
hierarchy of genus zero in the perspective of dispersionless Hirota equations.
In the case of one-variable reduction, dispersionless Hirota equations turn out
to be a powerful tool for understanding the mechanism of reduction. All
relevant equations describing the reduction (L\"owner-type equations and
diagonal hydrodynamic equations) can be thereby derived and justified in a
unified manner. The case of multi-variable reductions is not so
straightforward. Nevertheless, the reduction procedure can be formulated in a
general form, and justified with the aid of dispersionless Hirota equations. As
an application, previous results of Guil, Ma\~{n}as and Mart\'{\i}nez Alonso
are reconfirmed in this formulation.


title: Calculation of current-induced torque from spin continuity equation

abstract:
  Current-induced torque is formulated based on the spin continuity equation.
The formulation does not rely on the assumption of separation of local spin and
charge degrees of freedom, in contrast to approaches based on the $s$-$d$ model
or mean-field approximation of itinerant ferromagnetism. This new method would
be thus useful for the estimation of torques in actual materials by
first-principles calculations. As an example, the formalism is applied to the
adiabatic limit of the $s$-$d$ model in order to obtain the analytical
expression for torques and corresponding $\beta$ terms arising from spin
relaxation due to spin-flip scattering and spin-orbit interaction.


title: What is the Simplest Quantum Field Theory?

abstract:
  Conventional wisdom says that the simpler the Lagrangian of a theory the
simpler its perturbation theory, but an increased understanding of the
structure of the S-matrix in gauge theories and gravity has been pointing to
the opposite conclusion. In this paper we suggest that N=8 SUGRA has the
simplest interacting S-matrix in 4D. Using Grassmann coherent states for
external particles shows that amplitudes with maximal SUSY are smooth objects,
with the action of SUSY manifest. We show that all tree amplitudes in N=4 SYM
and N=8 SUGRA vanish at (supersymmetric) infinite complex momentum, and can
thus be determined by recursion relations. We also identify the action of the
non-linearly realized E_{7(7)} symmetry of N=8 SUGRA on scattering amplitudes.
We give a simple discussion of the structure of 1-loop amplitudes in any QFT,
in close parallel to recent work of Forde, showing that the coefficients of
scalar "triangle" and "bubble" integrals are determined by the "pole at
infinite momentum" of tree amplitude products appearing in cuts. The on-shell
superspace for maximal SUSY makes it easy to compute the multiplet sums that
arise in these cuts, leading to a simple proof of the absence of triangles and
bubbles at 1-loop. We also argue that rational terms are absent. This
establishes the recent conjecture that 1-loop amplitudes in N=8 SUGRA have only
scalar box integrals, just as N=4 SYM. It is natural to conjecture that with
maximal SUSY, amplitudes are completely determined by their leading
singularities even beyond tree- and 1-loop level; this would directly imply the
perturbative finiteness of N=8 SUGRA. The remarkable properties of scattering
amplitudes call for an explanation in terms of a "weak-weak" dual formulation
of QFT, a holographic dual of flat space.


title:
Confinement- Deconfinement Phase Transition in Hot and Dense QCD at
  Large N

abstract:
  We conjecture that the confinement- deconfinement phase transition in QCD at
large number of colors N and N_f\ll N at T\neq 0 and \mu\neq 0 is triggered by
the drastic change in \theta behavior. The conjecture is motivated by the
holographic model of QCD where confinement -deconfinement phase transition
indeed happens precisely at the value of temperature T=T_c where \theta
dependence experiences a sudden change in behavior[1]. The conjecture is also
supported by quantum field theory arguments when the instanton calculations
(which trigger the \theta dependence) are under complete theoretical control
for T>T_c, suddenly break down immediately below T<T_c with sharp changes in
the \theta dependence. Finally, the conjecture is supported by a number of
numerical lattice results. We employ this conjecture to study confinement
-deconfinement phase transition of dense QCD at large \mu in large N limit by
analyzing the \theta dependence. We find that the confinement- deconfinement
phase transition at N_f\ll N happens at very large quark chemical potential
\mu_c\sim \sqrt{N}\Lambda_{QCD}. This result agrees with recent findings by
McLerran and Pisarski[2]. We also speculate on case when N_f\sim N.


title: Markov switching models: an application to roadway safety

abstract:
  In this research, two-state Markov switching models are proposed to study
accident frequencies and severities. These models assume that there are two
unobserved states of roadway safety, and that roadway entities (e.g., roadway
segments) can switch between these states over time. The states are distinct,
in the sense that in the different states accident frequencies or severities
are generated by separate processes (e.g., Poisson, negative binomial,
multinomial logit). Bayesian inference methods and Markov Chain Monte Carlo
(MCMC) simulations are used for estimation of Markov switching models. To
demonstrate the applicability of the approach, we conduct the following three
studies. In the first study, two-state Markov switching count data models are
considered as an alternative to zero-inflated models for annual accident
frequencies, in order to account for preponderance of zeros typically observed
in accident frequency data. In the second study, two-state Markov switching
Poisson model and two-state Markov switching negative binomial model are
estimated using weekly accident frequencies on selected Indiana interstate
highway segments over a five-year time period. In the third study, two-state
Markov switching multinomial logit models are estimated for severity outcomes
of accidents occurring on Indiana roads over a four-year time period. One of
the most important results found in each of the three studies, is that in each
case the estimated Markov switching models are strongly favored by roadway
safety data and result in a superior statistical fit, as compared to the
corresponding standard (non-switching) models.


title: Pure spin current generation in a Rashba-Dresselhaus quantum channel

abstract:
  We demonstrate a spin pump to generate pure spin current of tunable intensity
and polarization in the absence of charge current. The pumping functionality is
achieved by means of an ac gate voltage that modulates the Rashba constant
dynamically in a local region of a quantum channel with both static Rashba and
Dresselhaus spin-orbit interactions. Spin-resolved Floquet scattering matrix is
calculated to analyze the whole scattering process. Pumped spin current can be
divided into spin-preserved transmission and spin-flip reflection parts. These
two terms have opposite polarization of spin current and are competing with
each other. Our proposed spin-based device can be utilized for non-magnetic
control of spin flow by tuning the ac gate voltage and the driving frequency.


title: Hypothesis testing for Gaussian states on bosonic lattices

abstract:
  The asymptotic state discrimination problem with simple hypotheses is
considered for a cubic lattice of bosons. A complete solution is provided for
the problems of the Chernoff and the Hoeffding bounds and Stein's lemma in the
case when both hypotheses are gauge-invariant Gaussian states with
translation-invariant quasi-free parts.


title:
The friction factor of two-dimensional rough-boundary turbulent soap
  film flows

abstract:
  We use momentum transfer arguments to predict the friction factor $f$ in
two-dimensional turbulent soap-film flows with rough boundaries (an analogue of
three-dimensional pipe flow) as a function of Reynolds number Re and roughness
$r$, considering separately the inverse energy cascade and the forward
enstrophy cascade. At intermediate Re, we predict a Blasius-like friction
factor scaling of $f\propto\textrm{Re}^{-1/2}$ in flows dominated by the
enstrophy cascade, distinct from the energy cascade scaling of
$\textrm{Re}^{-1/4}$. For large Re, $f \sim r$ in the enstrophy-dominated case.
We use conformal map techniques to perform direct numerical simulations that
are in satisfactory agreement with theory, and exhibit data collapse scaling of
roughness-induced criticality, previously shown to arise in the 3D pipe data of
Nikuradse.


title: Locally adaptive estimation of evolutionary wavelet spectra

abstract:
  We introduce a wavelet-based model of local stationarity. This model enlarges
the class of locally stationary wavelet processes and contains processes whose
spectral density function may change very suddenly in time. A notion of
time-varying wavelet spectrum is uniquely defined as a wavelet-type transform
of the autocovariance function with respect to so-called autocorrelation
wavelets. This leads to a natural representation of the autocovariance which is
localized on scales. We propose a pointwise adaptive estimator of the
time-varying spectrum. The behavior of the estimator studied in homogeneous and
inhomogeneous regions of the wavelet spectrum.


title: Structural and dynamical heterogeneities in two-dimensional melting

abstract:
  Using molecular dynamics simulation, we study structural and dynamical
heterogeneities at melting in two-dimensional one-component systems with 36000
particles. Between crystal and liquid we find intermediate hexatic states,
where the density fluctuations are enhanced at small wave number k as well as
those of the six-fold orientational order parameter. Their structure factors
both grow up to the smallest wave number equal to the inverse system length.
The intermediate scattering function of the density S(k,t) is found to relax
exponentially with decay rate Gamma_k ~ k^z with z~2.6 at small k in the
hexatic phase.


title: Some Non-Abelian Phase Spaces in Low Dimensions

abstract:
  A non-abelian phase space, or a phase space of a Lie algebra is a
generalization of the usual (abelian) phase space of a vector space. It
corresponds to a parak\"ahler structure in geometry. Its structure can be
interpreted in terms of left-symmetric algebras. In particular, a solution of
an algebraic equation in a left-symmetric algebra which is an analogue of
classical Yang-Baxter equation in a Lie algebra can induce a phase space. In
this paper, we find that such phase spaces have a symplectically isomorphic
property. We also give all such phase spaces in dimension 4 and some examples
in dimension 6. These examples can be a guide for a further development.


title: Personal Semantic Web Through A Space Based Computing Environment

abstract:
  The Semantic Web through technologies such to support the canonical
representation information and presenting it to users in a method by which its
meaning can be understood or at least communi- cated and interpreted by all
parties. As the Semantic Web evolves into more of a computing platform rather
than an information platform more dynamic structures, interactions and
behaviours will evolve leading to systems which localise and personalise this
Dynamic Semantic Web.


title: Diffuse interstellar bands in RAVE Survey spectra

abstract:
  We have used spectra of hot stars from the RAVE Survey in order to
investigate the visibility and properties of five diffuse interstellar bands
previously reported in the literature. The RAVE spectroscopic survey for
Galactic structure and kinematics records CCD spectra covering the 8400-8800
Ang wavelength region at 7500 resolving power. The spectra are obtained with
the UK Schmidt at the AAO, equipped with the 6dF multi-fiber positioner. The
DIB at 8620.4 Ang is by far the strongest and cleanest of all DIBs occurring
within the RAVE wavelength range, with no interference by underlying absorption
stellar lines in hot stars. It correlates so tightly with reddening that it
turns out to be a reliable tool to measure it, following the relation E(B-V) =
2.72 (+/- 0.03) x E.W.(Ang), valid throughout the general interstellar medium
of our Galaxy. The presence of a DIB at 8648 Ang is confirmed. Its intensity
appears unrelated to reddening, in agreement with scanty and preliminary
reports available in the literature, and its measurability is strongly
compromised by severe blending with underlying stellar HeI doublet at 8649 Ang.
The two weak DIBS at 8531 and 8572 Ang do not appear real and should actually
be blends of underlying stellar lines. The very weak DIB at 8439 Ang cannot be
resolved within the profile of the much stronger underlying hydrogen Paschen 18
stellar line.


title:
A stochastic differential game for the inhomogeneous $\infty$-Laplace
  equation

abstract:
  Given a bounded $\mathcaligr{C}^2$ domain $G\subset{\mathbb{R}}^m$, functions
$g\in\mathcaligr{C}(\partial G,{\mathbb{R}})$ and $h\in\mathcaligr
{C}(\bar{G},{\mathbb{R}}\setminus\{0\})$, let $u$ denote the unique viscosity
solution to the equation $-2\Delta_{\infty}u=h$ in $G$ with boundary data $g$.
We provide a representation for $u$ as the value of a two-player zero-sum
stochastic differential game.


title: Vertex Operator Algebra Analogue of Embedding $D_8$ into $E_8$

abstract:
  Let $L_{D_8}(1, 0)$ and $L_{E_8}(1, 0)$ be the simple vertex operator
algebras associated to untwisted affine Lie algebra $\widehat{{\mathbf
g}}_{D_{8}}$ and $\widehat{{\mathbf g}}_{E_8}$ with level 1 respectively. In
the 1980s by I. Frenkel, Lepowsky and Meurman as one of the many important
preliminary steps toward their construction of the moonshine module vertex
operator algebra, they use roots lattice showing that $L_{D_8}(1, 0)$ can embed
into $L_{E_8}(1, 0)$ as a vertex operator subalgebra(\cite{5, 6, 8}). Their
construct is a base of vertex operator theory.
  But the embedding they gave using the fact $L_{\mathbf g}(1,0)$ is isomorphic
to its root lattice vertex operator algebra $V_L$. In this paper, we give an
explicitly construction of the embedding and show that as an $L_{D_8}(1,
0)$-module, $L_{E_8}(1, 0)$ is isomorphic to the extension of $L_{D_8}(1, 0)$
by its simple module $L_{D_8}(1, \overline{\omega}_8)$. It may be convenient to
be used for conformal field theory.


title: Giant Extrinsic Spin Hall Effect due to Rare-Earth Impurities

abstract:
  We investigate the extrinsic spin Hall effect in the electron gas model due
to magnetic impurities, by focusing on Ce- and Yb-impurities. In the dilute
limit, the skew scattering term dominates the side jump term. For
Ce-impurities, the spin Hall angle $\alpha_{\rm SH}$ due to skew scattering is
given by $-8\pi\sin\delta_2/7$, where $\delta_2 (\ll 1)$ is the phase shift
for$d (l=2)$ partial wave. Since $\alpha_{\rm SH}$ reaches $O(10^{-1})$ if
$\delta_2 \simge 0.03$, the spin Hall effect is anticipated to be considerable
in metals with rare-earth impurities. The giant extrinsic SHE originates from
the large orbital angular momentum, which is also significant for the intrinsic
SHE.


title:
Simple derivation of Young, Wenzel and Cassie-Baxter equations and its
  interpretations

abstract:
  In this paper we have derived Young's, Wenzel's and Cassie-Baxter's equations
using conceptual model rather than showing rigorous derivation to help the
new-comers in this field. We then pointed out that if the substrate is
initially hydorphilic then one can modify the surface morphology and make the
substrate to become hydrophobic or superhydrophobic. But, if the substrate is
initially hydrophobic then one can only make it superhydrophobic but not
hydrophilic by modifying the surface morphology using the formalisms mentioned
in this paper


title: Influence of primordial magnetic fields on 21 cm emission

abstract:
  Magnetic fields in the early universe can significantly alter the thermal
evolution and the ionization history during the dark ages. This is reflected in
the 21 cm line of atomic hydrogen, which is coupled to the gas temperature
through collisions at high redshifts, and through the Wouthuysen-Field effect
at low redshifts. We present a semi-analytic model for star formation and the
build-up of a Lyman alpha background in the presence of magnetic fields, and
calculate the evolution of the mean 21 cm brightness temperature and its
frequency gradient as a function of redshift. We further discuss the evolution
of linear fluctuations in temperature and ionization in the presence of
magnetic fields and calculate the effect on the 21 cm power spectrum. At high
redshifts, the signal is increased compared to the non-magnetic case due to the
additional heat input into the IGM from ambipolar diffusion and the decay of
MHD turbulence. At lower redshifts, the formation of luminous objects and the
build-up of a Lyman alpha background can be delayed by a redshift interval of
10 due to the strong increase of the filtering mass scale in the presence of
magnetic fields. This tends to decrease the 21 cm signal compared to the
zero-field case. In summary, we find that 21 cm observations may become a
promising tool to constrain primordial magnetic fields.


title:
The X boson (MX ~ 1014 GeV) mediation of the HI relativistic reactions
  generated by RHIC and LHC

abstract:
  In this paper the model for the p-p accretion process in HI reactions is
described. The mediation by X boson (MX ~ 1014 GeV) is outlined. The Heaviside
equation for the thermal processes in HI scattering is obtained and solved. The
possibility of the detection of the collective excitation in HI generated by
RHIC and LHC


title:
A family of Koszul algebras arising from finite-dimensional
  representations of simple Lie algebras

abstract:
  Let $\lie g$ be a simple Lie algebra and let $\bs^{\lie g}$ be the locally
finite part of the algebra of invariants $(_\bc\bv\otimes S(\lie g))^{\lie g}$
where $\bv$ is the direct sum of all simple finite-dimensional modules for
$\lie g$ and $S(\lie g)$ is the symmetric algebra of $\lie g$. Given an
integral weight $\xi$, let $\Psi=\Psi(\xi)$ be the subset of roots which have
maximal scalar product with $\xi$. Given a dominant integral weight $\lambda$
and $\xi$ such that $\Psi$ is a subset of the positive roots we construct a
finite-dimensional subalgebra $\bs^{\lie g}_\Psi(\le_\Psi\lambda)$ of
$\bs^{\lie g}$ and prove that the algebra is Koszul of global dimension at most
the cardinality of $\Psi$. Using this we then construct naturally an
infinite-dimensional Koszul algebra of global dimension equal to the
cardinality of $\Psi$. The results and the methods are motivated by the study
of the category of finite-dimensional representations of the affine and quantum
affine algebras.


title: Achieving High Curie Temperature in (Ga,Mn)As

abstract:
  We study the effects of growth temperature, Ga:As ratio and post-growth
annealing procedure on the Curie temperature, Tc, of (Ga,Mn)As layers grown by
molecular beam epitaxy. We achieve the highest Tc values for growth
temperatures very close to the 2D-3D phase boundary. The increase in Tc, due to
the removal of interstitial Mn by post growth annealing, is counteracted by a
second process which reduces Tc and which is more effective at higher annealing
temperatures. Our results show that it is necessary to optimize the growth
parameters and post growth annealing procedure to obtain the highest Tc.


title: A low background facility inside the LVD detector at Gran Sasso

abstract:
  The Large Volume Detector (LVD) in the Gran Sasso Laboratory of INFN is an
observatory mainly devoted to search for neutrinos from core collapse
supernovae. It consists of 1000 tons of liquid scintillator divided in 840
stainless steel tanks 1.5m$^3$ each. In this letter we present the possibility
for LVD to work both as a passive shield and moderator for the low energy gamma
and neutron background and as an active veto for muons and higher energy
neutrons. An inner region inside the LVD structure ("LVD Core Facility") can be
identified, with a volume of about 30m$^3$, with the neutron background typical
of an underground laboratory placed at a much deeper site. This region can be
realized with a negligible impact on the LVD operation and sensitive mass. The
LVD Core Facility could be effectively exploited by a compact experiment for
the search of rare events, such as double beta decay or dark matter.


title:
Strong Off-Resonant Enhancement of Spontaneous Emission in
  Metal-Dielectric-Metal Plasmon Waveguide Structures

abstract:
  We theoretically investigate the spontaneous emission process of an optical,
dipolar emitter in metal-dielectric-metal slab and slot waveguide structures.
We find that both structures exhibit strong off-resonant emission enhancements
due to the tight confinement of modes between two metallic plates. The large
enhancement of surface plasmon-polariton excitation enables dipole emission to
be preferentially coupled into plasmon waveguide modes. These structures find
applications in creating nanoscale local light sources or in generating guided
single plasmons in integrated optical circuits.


title:
Tight--binding description of the quasiparticle dispersion of graphite
  and few--layer graphene

abstract:
  A universal set of third--nearest neighbour tight--binding (TB) parameters is
presented for calculation of the quasiparticle (QP) dispersion of $N$ stacked
$sp^2$ graphene layers ($N=1... \infty$) with $AB$ stacking sequence. The QP
bands are strongly renormalized by electron--electron interactions which
results in a 20% increase of the nearest neighbour in--plane and out--of--plane
TB parameters when compared to band structure from density functional theory.
With the new set of TB parameters we determine the Fermi surface and evaluate
exciton energies, charge carrier plasmon frequencies and the conductivities
which are relevant for recent angle--resolved photoemission, optical, electron
energy loss and transport measurements. A comparision of these quantitities to
experiments yields an excellent agreement. Furthermore we discuss the
transition from few layer graphene to graphite and a semimetal to metal
transition in a TB framework.


title:
Monitoring of band gap and magnetic state of graphene nanoribbons
  through vacancies

abstract:
  Using first-principles plane wave calculations we predict that electronic and
magnetic properties of graphene nanoribbons can be affected by defect-induced
itinerant states. The band gaps of armchair nanoribbons can be modified by
hydrogen saturated holes. Defects due to periodically repeating vacancy or
divacancies induce metallization, as well as magnetization in non-magnetic
semiconducting nanoribbons due to the spin-polarization of local defect states.
Antiferromagnetic ground state of semiconducting zigzag ribbons can change to
ferrimagnetic state upon creation of vacancy defects, which reconstruct and
interact with edge states. Even more remarkable is that all these effects of
vacancy defects are found to depend on their geometry and position relative to
edges. It is shown that these effects can, in fact, be realized without really
creating defects.


title: A First-Principles Constitutive Equation for Suspension Rheology

abstract:
  Using mode-coupling theory, we derive a constitutive equation for the
nonlinear rheology of dense colloidal suspensions under arbitrary
time-dependent homogeneous flow. Generalizing previous results for simple
shear, this allows the full tensorial structure of the theory to be identified.
Macroscopic deformation measures, such as the Cauchy-Green tensors, thereby
emerge. So does a direct relation between the stress and the distorted
microstructure, illuminating the interplay of slow structural relaxation and
arbitrary imposed flow. We present flow curves for steady planar and uniaxial
elongation and compare these to simple shear. The resulting non-linear Trouton
ratios point to a tensorially nontrivial dynamic yield condition for colloidal
glasses.


title: Encompression Using Two-dimensional Cellular Automata Rules

abstract:
  In this paper, we analyze the algebraic structure of some null boundary as
well as some periodic boundary 2-D Cellular Automata (CA) rules by introducing
a new matrix multiplication operation using only AND, OR instead of most
commonly used AND, EX-OR. This class includes any CA whose rule, when written
as an algebra, is a finite Abelean cyclic group in case of periodic boundary
and a finite commutative cyclic monoid in case of null boundary CA
respectively. The concept of 1-D Multiple Attractor Cellular Automata (MACA) is
extended to 2-D. Using the family of 2-D MACA and the finite Abelian cyclic
group, an efficient encompression algorithm is proposed for binary images.


title:
The complex galaxy cluster Abell 514: New results obtained with the XMM
  - Newton satellite

abstract:
  We study the X-ray morphology and dynamics of the galaxy cluster Abell 514.
Also, the relation between the X-ray properties and Faraday Rotation measures
of this cluster are investigated in order to study the connection of magnetic
fields and the intra-cluster medium. We use two combined XMM - Newton pointings
that are split into three distinct observations. The data allow us to evaluate
the overall cluster properties like temperature and metallicity with high
accuracy. Additionally, a temperature map and the metallicity distribution are
computed, which are used to study the dynamical state of the cluster in detail.
Abell 514 represents an interesting merger cluster with many substructures
visible in the X-ray image and in the temperature and abundance distributions.
The new XMM - Newton data of Abell 514 confirm the relation between the X-ray
brightness and the sigma of the Rotation Measure (S_X - sigma_RM relation)
proposed by Dolag et al. (2001).


title:
A First-Principles Constitutive Equation for Suspension Rheology:
  Supplementary Material

abstract:
  Additional supplementary material for the paper `A First-Principles
Constitutive Equation for Suspension Rheology'.


title:
The complementary group of proper motions of the Minkowski metric in an
  arbitrary dimension space

abstract:
  It is shown that the Poincare group which is a semidirect product of the
group of translations and the Lorentz group, is not a single physicaly
important group of proper motions of Minkowski metric. The complementary group
of proper motions of the metric in a class of noninertial reference system has
been found.


title: Experimental Evidence for Optimal Resonances in Pion-Nucleus Scattering

abstract:
  Experimental data on the pion-nucleus total cross sections are analyzed in
terms of the optimal resonances predictions (OR). The OR-predictions are found
in a good agreement with the actual experimental data in the region
corresponding to the Delta(1236) resonance in elementary pi-N scattering. The
essential signatures of the optimal resonances are experimentally verified with
high accuracy.


title:
Experimental and Theoretical Investigation of the Barrier Pyroelectric
  Effect in a Quantum Paraelectric Semiconductor

abstract:
  We describe here the first comprehensive investigation of a pyroelectric
response of a p-n junction in a non-polar paraelectric semiconductor. The
pyroelectric effect is generated by the, temperature dependent, built-in
electrical dipole moment. High quality PbTe p-n junctions have been prepared
specifically for this experiment. The pyroelectric effect was excited by a
continuous CO2 laser beam, modulated by a mechanical chopper. The shape and
amplitude of the periodic and single-pulse pyroelectric signals were studied as
a function of temperature (10K-130K), reverse bias voltage (up to -500 mV) and
chopping frequency (4Hz-2000Hz). The pyroelectric coefficient is about 10^(-3)
microC/cm2K in the temperature region 40 - 80 K. The developed theoretical
model quantitatively describes all the experimental features of the observed
pyroelectric effect. The time evolution of the temperature within the p-n
junction was reconstructed.


title: Heegner points and Eisenstein series

abstract:
  We give an alternative computation of the twisted second moment of critival
values of class group $L$-functions attached to an imaginary quadratic field.
The method avoids long calculations and yields the expected polynomial growth
in the $s$-parameter for the remaining term.


title: Looking for Groebner Basis Theory for (Almost) Skew 2-Nomial Algebras

abstract:
  In this paper, we introduce (almost) skew 2-nomial algebras and look for a
one-sided or two-sided Gr\"obner basis theory for such algebras at a modest
level. That is, we establish the existence of a skew multiplicative $K$-basis
for every skew 2-nomial algebra, and we explore the existence of a (left,
right, or two-sided) monomial ordering for an (almost) skew 2-nomial algebra.
As distinct from commonly recognized algebras holding a Gr\"obner basis theory
(such as algebras of the solvable type [K-RW] and some of their homomorphic
images), a subclass of skew 2-nomial algebras that have a left Gr\"obner basis
theory but may not necessarily have a two-sided Gr\"obner basis theory,
respectively a subclass of skew 2-nomial algebras that have a right Gr\"obner
basis theory but may not necessarily have a two-sided Gr\"obner basis theory,
are determined such that numerous quantum binomial algebras (which provide
binomial solutions to the Yang-baxter equation [Laf], [G-I2]) are involved.


title:
XY model on the circle: diagonalization, spectrum, and forerunners of
  the quantum phase transition

abstract:
  We exactly diagonalize the finite-size XY model with periodic boundary
conditions and analytically determine the ground state energy. We show that
there are two types of fermions: singles and pairs, whose dispersion relations
have a completely arbitrary gauge-dependent sign. It follows that the ground
state is determined by a competition between the vacuum states (with a suitable
gauge) of two parity sectors. We finally exhibit some points in finite size
systems that forerun criticality. They are associated to single Bogoliubov
fermions and to the level crossings between physical and unphysical states. In
the thermodynamic limit they approach the ground state and build up
singularities at logarithmic rates.

categories: quant-ph cond-mat.stat-mech math-ph math.MP


title: Non-linear graphene optics for terahertz applications

abstract:
  The linear electrodynamic properties of graphene -- the frequency-dependent
conductivity, the transmission spectra and collective excitations -- are
briefly outlined. The non-linear frequency multiplication effects in graphene
are studied, taking into account the influence of the self-consistent-field
effects and of the magnetic field. The predicted phenomena can be used for
creation of new devices for microwave and terahertz optics and electronics.


title: Apery, Bessel, Calabi-Yau and Verrill

abstract:
  A differential equation related to the moments of Bessel functions is shown
to have a solution at infinity with coefficients being squares of binomial
coefficients.


title: Optical spectroscopy of 3CR sample of radio sources at z<0.3

abstract:
  We are carrying out a program of optical spectroscopy of the complete
subsample of the 3CR catalog of radio sources at redshift z < 0.3. The sample
consists of 113 3CR sources, comprising FR I, FR II radio galaxies and Quasars.
Complete datasets in other bands are already or will be soon available for the
whole sample but the optical spectra are sparse and inhomogeneous in quality.
The observations are carried out at the 3.58m Telescopio Nazionale Galileo
(TNG, La Palma). More than 100 sources have been already observed. We present
here the preliminary results on the analysis of the high and low resolution
spectra. We found that sources can be spectroscopically characterized as: High
Excitation Galaxies (HEG), Low Excitation Galaxies (LEG) and "Relic" AGNs. This
classification is supported by the optical - radio correlations in which
objects spectroscopically different follow different correlations. We conclude
that AGNs with the same radio power can be fueled with different accretion
properties. "Relic" radio-galaxies are characterized by extreme low excitation
spectra that we interpret as nuclei whose activity has recently turned-off. The
full spectral catalog will be made available to the scientific community.


title: On hyperbolic cohomology classes

abstract:
  We study hyperbolic cohomology classes in the general context of simplicial
complexes and prove homological invariance statements for them. We relate the
existence of hyperbolic cohomology classes to the non-amenability of the
fundamental group. In degree two we clarify the relation between hyperbolic and
atoroidal classes, leading to an application to symplectically atoroidal
manifolds.


title: Graded annihilators and tight closure test ideals

abstract:
  Let $R$ be a commutative Noetherian local ring of prime characteristic $p$.
The main purposes of this paper are to show that if the injective envelope $E$
of the simple $R$-module has a structure as a torsion-free left module over the
Frobenius skew polynomial ring over $R$, then $R$ has a tight closure test
element (for modules) and is $F$-pure, and to relate the test ideal of $R$ to
the smallest '$E$-special' ideal of $R$ of positive height.
  A byproduct is an analogue of a result of Janet Cowden Vassilev: she showed,
in the case where $R$ is an $F$-pure homomorphic image of an $F$-finite regular
local ring, that there exists a strictly ascending chain $0 = \tau_0 \subset
\tau_1 \subset ... \subset \tau_t = R$ of radical ideals of $R$ such that, for
each $i = 0, ..., t-1$, the reduced local ring $R/\tau_i$ is $F$-pure and its
test ideal (has positive height and) is exactly $\tau_{i+1}/\tau_i$. This paper
presents an analogous result in the case where $R$ is complete (but not
necessarily $F$-finite) and $E$ has a structure as a torsion-free left module
over the Frobenius skew polynomial ring. Whereas Cowden Vassilev's results were
based on R. Fedder's criterion for $F$-purity, the arguments in this paper are
based on the author's work on graded annihilators of left modules over the
Frobenius skew polynomial ring.


title: Dynamics of Polymer Decompression: Expansion, Unfolding and Ejection

abstract:
  The dynamics of polymer decompression, i.e., a process from compressed,
compact state to the relaxed swoll en conformation, can be formally described
as a {\it nonlinear diffusion}. We discuss here two basic examples: (i) the
expansion, or unfolding from a compact state, and (ii) the ejection of pressed
polymer through a pore. The problem can be solved exactly for the case (i), but
not for the latter. Even in such situations, a scheme called {\it uniform
approximation} is shown to be useful to get a physical insight involved. Its
application to the case (ii) is able to account for conflicting numerical data
in a consistent way.