title: A note on the large-angle anisotropies in the WMAP cut-sky maps

abstract:
  Recent analyses of the WMAP data seem to indicate the possible presence of
large-angle anisotropy in the Universe. If confirmed, these can have important
consequences for our understanding of the Universe. A number of attempts have
recently been made to establish the reality and nature of such anisotropies in
the CMB data. Among these is a directional indicator recently proposed by the
authors. A distinctive feature of this indicator is that it can be used to
generate a sky map of the large-scale anisotropies of the CMB maps. Applying
this indicator to full-sky temperature maps we found a statistically
significant preferred direction. The full-sky maps used in these analyses are
known to have residual foreground contamination as well as complicated noise
properties. Thus, here we performed the same analysis for a map where regions
with high foreground contamination were removed. We find that the main feature
of the full-sky analysis, namely the presence of a significant axis of
asymmetry, is robust with respect to this masking procedure. Other subtler
anomalies of the full-sky are on the other hand no longer present.


title:
Multi-site observations of Delta Scuti stars 7 Aql and 8 Aql (a new
  Delta Scuti variable): The twelfth STEPHI campaign in 2003

abstract:
  We present an analysis of the pulsation behaviour of the Delta Scuti stars 7
Aql (HD 174532) and 8 Aql (HD 174589) -- a new variable star -- observed in the
framework of STEPHI XII campaign during 2003 June--July. 183 hours of high
precision photometry were acquired by using four-channel photometers at three
sites on three continents during 21 days. The light curves and amplitude
spectra were obtained following a classical scheme of multi-channel photometry.
Observations in different filters were also obtained and analyzed. Six and
three frequencies have been unambiguously detected above a 99% confidence level
in the range 0.090 mHz--0.300 mHz and 0.100 mHz-- 0.145 mHz in 7 Aql and 8 Aql
respectively. A comparison of observed and theoretical frequencies shows that 7
Aql and 8 Aql may oscillate with p modes of low radial orders, typical among
Delta Scuti stars. In terms of radial oscillations the range of 8 Aql goes from
n=1 to n=3 while for 7 Aql the range spans from n=4 to n=7. Non-radial
oscillations have to be present in both stars as well. The expected range of
excited modes according to a non adiabatic analysis goes from n=1 to n=6 in
both stars.


title:
Superconductivity in Rh$_2$Ga$_9$ and Ir$_2$Ga$_9$ without Inversion
  Symmetry

abstract:
  Superconductivity with $T_{\rm c}$ $\simeq$ 2 K was discovered in the
intermetallic binary compounds Rh$_2$Ga$_9$ and Ir$_2$Ga$_9$. This is the first
observation of superconductivity in the Rh-Ga and Ir-Ga binary systems. Both
compounds crystallize in a distorted Co$_2$Al$_9$-type structure (monoclinic,
space group: $Pc$), which lacks spatial inversion symmetry. Specific heat
measurements revealed that both compounds are weak-coupling BCS superconductors
having an isotropic superconducting gap. Measurements in magnetic fields
indicated type-I superconductivity with a critical field $H_{\rm c}(0)$
$\simeq$ 130 Oe for Rh$_2$Ga$_9$ and type-II superconductivity with an upper
critical field $H_{\rm c2}(0)$ $\simeq$ 250 Oe for Ir$_2$Ga$_9$.


title:
Expressing Combinatorial Optimization Problems by Systems of Polynomial
  Equations and the Nullstellensatz

abstract:
  Systems of polynomial equations over the complex or real numbers can be used
to model combinatorial problems. In this way, a combinatorial problem is
feasible (e.g. a graph is 3-colorable, hamiltonian, etc.) if and only if a
related system of polynomial equations has a solution. In the first part of
this paper, we construct new polynomial encodings for the problems of finding
in a graph its longest cycle, the largest planar subgraph, the edge-chromatic
number, or the largest k-colorable subgraph.
  For an infeasible polynomial system, the (complex) Hilbert Nullstellensatz
gives a certificate that the associated combinatorial problem is infeasible.
Thus, unless P = NP, there must exist an infinite sequence of infeasible
instances of each hard combinatorial problem for which the minimum degree of a
Hilbert Nullstellensatz certificate of the associated polynomial system grows.
  We show that the minimum-degree of a Nullstellensatz certificate for the
non-existence of a stable set of size greater than the stability number of the
graph is the stability number of the graph. Moreover, such a certificate
contains at least one term per stable set of G. In contrast, for non-3-
colorability, we found only graphs with Nullstellensatz certificates of degree
four.


title: Affine Structures on a Ringed Space and Schemes

abstract:
  In this paper we will first introduce the notion of affine structures on a
ringed space and then obtain several properties. Affine structures on a ringed
space, arising mainly from complex analytical spaces of algebraic schemes over
number fields, behave like differential structures on a smooth manifold.
  As one does for differential manifolds, we will use pseudogroups of affine
transformations to define affine atlases on a ringed space. An atlas on a space
is said to be an affine structure if it is maximal. An affine structure is
admissible if there is a sheaf on the underlying space such that they are
coincide on all affine charts, which are in deed affine open sets of a scheme.
In a rigour manner, a scheme is defined to be a ringed space with a specified
affine structure if the affine structures are in action in some special cases
such as analytical spaces of algebraic schemes. Particularly, by the whole of
affine structures on a space, we will obtain respectively necessary and
sufficient conditions that two spaces are homeomorphic and that two schemes are
isomorphic, which are the two main theorems of the paper. It follows that the
whole of affine structures on a space and a scheme, as local data, encode and
reflect the global properties of the space and the scheme, respectively.


title:
Efficient Batch Update of Unique Identifiers in a Distributed Hash Table
  for Resources in a Mobile Host

abstract:
  Resources in a distributed system can be identified using identifiers based
on random numbers. When using a distributed hash table to resolve such
identifiers to network locations, the straightforward approach is to store the
network location directly in the hash table entry associated with an
identifier. When a mobile host contains a large number of resources, this
requires that all of the associated hash table entries must be updated when its
network address changes.
  We propose an alternative approach where we store a host identifier in the
entry associated with a resource identifier and the actual network address of
the host in a separate host entry. This can drastically reduce the time
required for updating the distributed hash table when a mobile host changes its
network address. We also investigate under which circumstances our approach
should or should not be used. We evaluate and confirm the usefulness of our
approach with experiments run on top of OpenDHT.


title: Stabilizing the monodromy of an open book decomposition

abstract:
  We prove that any mapping class on a compact oriented surface with nonempty
boundary can be made pseudo-Anosov and right-veering after a sequence of
positive stabilizations.


title:
Ground state phase diagram and magnetoconductance of a one-dimensional
  Hubbard superlattice at half-filling

abstract:
  We have studied a one dimensional Hubbard superlattice with different Coulomb
correlations at alternating sites for a half-filled band. Mean field
calculations based on the Hartree-Fock approximation together with a real space
renormalization group technique were used to study the ground state of the
system. The phase diagrams obtained in these approaches agree with each other
from the weak to the intermediate coupling regime. The mean field results show
very quick convergence with system size. The renormalization group results
indicate a spatial modulation of local moments that was identified in some
previous work. Also we have studied the magnetoconductance of such
superlattices which reveals several interesting points.


title:
Determination of InN-GaN heterostructure band offsets from internal
  photoemission measurements

abstract:
  Band discontinuities at the InN-GaN heterointerface are experimentally
determined from internal photoemission spectroscopy measurements on n+ InN on
GaN epilayers. The photocurrent shows two threshold energies, one at 1.624 eV
and the other at 2.527 eV. From these we obtain the valence band offset 0.85 eV
and the conduction band offset 1.82 eV.


title:
Rotation of an atomic Bose-Einstein condensate with and without a
  quantized vortex

abstract:
  We theoretically examine the rotation of an atomic Bose-Einstein condensate
in an elliptical trap, both in the absence and presence of a quantized vortex.
Two methods of introducing the rotating potential are considered -
adiabatically increasing the rotation frequency at fixed ellipticity, and
adiabatically increasing the trap ellipticity at fixed rotation frequency.
Extensive simulations of the Gross-Pitaevskii equation are employed to map out
the points where the condensate becomes unstable and ultimately forms a vortex
lattice. We highlight the key features of having a quantized vortex in the
initial condensate. In particular, we find that the presence of the vortex
causes the instabilities to shift to lower or higher rotation frequencies,
depending on the direction of the vortex relative to the trap rotation.


title: A Novel Model of Working Set Selection for SMO Decomposition Methods

abstract:
  In the process of training Support Vector Machines (SVMs) by decomposition
methods, working set selection is an important technique, and some exciting
schemes were employed into this field. To improve working set selection, we
propose a new model for working set selection in sequential minimal
optimization (SMO) decomposition methods. In this model, it selects B as
working set without reselection. Some properties are given by simple proof, and
experiments demonstrate that the proposed method is in general faster than
existing methods.


title:
Extended Optical Model Analyses of Elastic Scattering and Fusion Cross
  Section Data for the 7Li+208Pb System at Near-Coulomb-Barrier Energies using
  the Folding Potential

abstract:
  Simultaneous $\chi^{2}$ analyses previously made for elastic scattering and
fusion cross section data for the $^{6}$Li+$^{208}$Pb system is extended to the
$^{7}$Li+$^{208}$Pb system at near-Coulomb-barrier energies based on the
extended optical model approach, in which the polarization potential is
decomposed into direct reaction (DR) and fusion parts. Use is made of the
double folding potential as a bare potential. It is found that the experimental
elastic scattering and fusion data are well reproduced without introducing any
normalization factor for the double folding potential and that both the DR and
fusion parts of the polarization potential determined from the $\chi^{2}$
analyses satisfy separately the dispersion relation. Further, we find that the
real part of the fusion portion of the polarization potential is attractive
while that of the DR part is repulsive except at energies far below the Coulomb
barrier energy. A comparison is made of the present results with those obtained
from the Continuum Discretized Coupled Channel (CDCC) calculations and a
previous study based on the conventional optical model with a double folding
potential. We also compare the present results for the $^7$Li+$^{208}$Pb system
with the analysis previously made for the $^{6}$Li+$^{208}$Pb system.


title: Time Evolution of Cosmic Ray MHD Shocks and Their Emissions

abstract:
  We present results of time evolution of oblique MHD plane shocks including
diffusive cosmic ray acceleration with backreaction on the plasma flows. The
simulations include self-consistent effects of finite Alfven wave propagation
and dissipation. From the computed cosmic ray particle phase space
distributions we calculate expected leptonic and hadronic emissions resulting
from interactions between the cosmic rays, magnetic fields, the thermal
particle population and relevant astrophysical photon fields.


title: Hall magnetoresistivity response under Microwave excitation revisited

abstract:
  We theoretically analyzed the microwave-induced modification of the Hall
magnetoresistivity in high mobility two-dimensional electron systems. These
systems present diagonal magnetoresistivity oscillations and zero-resistance
states when are subjected to microwave radiation. The most surprising
modification of the Hall magnetoresistivity is a periodic reduction which
correlates with a periodic increase in the diagonal resistivity. We present a
model that explains the experimental results considering that radiation affects
directly only the diagonal resistivity and the observed Hall resistivity
changes are coming from the tensor relationship between both of them.


title: QCD in hadronic B decays

abstract:
  The perturbative QCD approach is based on $k_T$ factorization, including the
Sudakov form factors so that to avoid the endpoint singularity. In this
approach, we calculate the charmless B decays like $B\to \pi\pi$ decays etc. to
produce the right number of branching ratios and also CP asymmetry parameters.
For final states with at least one charmed meson, like $B\to D\pi$ decays, our
results also agree with the experiments.


title: On products of T-ideals in free algebras and free group algebras

abstract:
  Let F be a field and A a free associative F-algebra or a group algebra of a
free group with an infinite set X of generators. We find a necessary and
sufficient condition for the inclusion I' into I, where I=I_1...I_k and
I'=I'_1...I'_l are any products of T-ideals in A. A canonical reformulation in
terms of products of group representation varieties answers a question posed in
1986


title: Perturbative Charged Rotating 5D Einstein-Maxwell Black Holes

abstract:
  We present perturbative charged rotating 5D Einstein-Maxwell black holes with
spherical horizon topology. The electric charge Q is the perturbative
parameter, the perturbations being performed up to 4th order. The expressions
for the relevant physical properties of these black holes are given. The
gyromagnetic ratio g, in particular, is explicitly shown to be non-constant in
higher order, and thus to deviate from its lowest order value, g=3. Comparison
of the perturbative analytical solutions with their non-perturbative numerical
counterparts shows remarkable agreement.


title:
Semiclassical expansions in the Toda hierarchy and the hermitian matrix
  model

abstract:
  An iterative algorithm for determining a class of solutions of the
dispersionful 2-Toda hierarchy characterized by string equations is developed.
This class includes the solution which underlies the large N-limit of the
Hermitian matrix model in the one-cut case. It is also shown how the double
scaling limit can be naturally formulated in this scheme


title: Hodge polynomials of the moduli spaces of rank 3 pairs

abstract:
  Let $X$ be a smooth projective curve of genus $g\geq 2$ over the complex
numbers. A holomorphic triple $(E_1,E_2,\phi)$ on $X$ consists of two
holomorphic vector bundles $E_1$ and $E_2$ over $X$ and a holomorphic map
$\phi:E_2 \to E_1$. There is a concept of stability for triples which depends
on a real parameter $\sigma$. In this paper, we determine the Hodge polynomials
of the moduli spaces of $\sigma$-stable triples with $\rk(E_1)=3$,
$\rk(E_2)=1$, using the theory of mixed Hodge structures. This gives in
particular the Poincar\'e polynomials of these moduli spaces. As a byproduct,
we recover the Hodge polynomial of the moduli space of odd degree rank 3 stable
vector bundles.


title:
Lagrangian temperature, velocity and local heat flux measurement in
  Rayleigh-Benard convection

abstract:
  We have developed a small, neutrally buoyant, wireless temperature sensor.
Using a camera for optical tracking, we obtain simultaneous measurements of
position and temperature of the sensor as it is carried along by the flow in
Rayleigh-B\'enard convection, at $Ra \sim 10^{10}$. We report on statistics of
temperature, velocity, and heat transport in turbulent thermal convection. The
motion of the sensor particle exhibits dynamics close to that of Lagrangian
tracers in hydrodynamic turbulence. We also quantify heat transport in plumes,
revealing self-similarity and extreme variations from plume to plume.


title: Almost-Commutative Geometries Beyond the Standard Model II: New Colours

abstract:
  We will present an extension of the standard model of particle physics in its
almost-commutative formulation. This extension is guided by the minimal
approach to almost-commutative geometries employed in [13], although the model
presented here is not minimal itself.
  The corresponding almost-commutative geometry leads to a Yang-Mills-Higgs
model which consists of the standard model and two new fermions of opposite
electro-magnetic charge which may possess a new colour like gauge group. As a
new phenomenon, grand unification is no longer required by the spectral action.


title: Cherenkov gluons (predictions and proposals)

abstract:
  The coherent hadron production analogous to Cherenkov radiation of photons
gives rise to the ring-like events. Being projected on the ring diameter they
produce the two-bump structure recently observed for the away-side jets at
RHIC. The position of the peaks and their height determine such properties of
the hadronic medium as its nuclear refractive index, the parton density, the
free path length and the energy loss of Cherenkov gluons. Cherenkov gluons may
be responsible for the asymmetry of dilepton mass spectra near rho-meson
observed in experiment. Beside comparatively low energy gluons observed at
RHIC, there could be high energy gluons at LHC, related to the high energy
region of positive real part of the forward scattering amplitude and possessing
different characteristics. This would allow to scan (x, Q^2)-plane determining
the parton densities in its various regions.


title:
Microscopic Approach in Inelastic Heavy-Ions Scattering with Excitation
  of Nuclear Collective States

abstract:
  In the density distribution of a deformed target-nucleus, the spherical
$\lambda = 0$ and the deformed $\lambda = 2$ parts were considered. On this
basis, the corresponding potential parts $U_0$ and $U^{(2)}_{int}$ of a double
-folding microscopic nucleus-nucleus optical potential are obtained. Then, for
these potentials and by using the coupled-channel technique (ECIS), the elastic
and inelastic amplitudes are calculated for $^{17}O$ heavy ion scattering on
$2^{+}$ collective excited state of various target nuclei. Besides, the same
cross-sections are calculated in the frame of an adiabatic approach of the
eikonal approximation, where the inelastic amplitude is the linear function of
$U^{(2)}_{int}$. Both the obtained results are compared with the experimental
data, and also discuss their efficiency in predicting the deformation
parameters of nuclei.


title:
Uniqueness of reconstruction and an inversion procedure for
  thermoacoustic and photoacoustic tomography

abstract:
  The paper contains a simple approach to reconstruction in Thermoacoustic and
Photoacoustic Tomography. The technique works for any geometry of point
detectors placement and for variable sound speed satisfying a non-trapping
condition. A uniqueness of reconstruction result is also obtained.


title: High distance Heegaard splittings via fat train tracks

abstract:
  We define "fat" train tracks and use them to give a combinatorial criterion
for the Hempel distance of Heegaard splittings for closed orientable
3-manifolds. We apply this criterion to 3-manifolds obtained from surgery on
knots in the three sphere.


title: Embedded soliton solutions : A variational study

abstract:
  We use a variational method to construct soliton solutions for systems
characterized by opposing dispersion and competing nonlinearities at
fundamental and second harmonics. We show that both ordinary and embedded
solitons tend to gain energy when the second harmonic field becomes weaker than
the first harmonic field.


title: Dark solitons in a superfluid Fermi gas

abstract:
  We investigate the behavior of dark solitons in a superfluid Fermi gas along
the BCS-BEC crossover by solving the Bogoliubov - de Gennes equations and
looking for real and odd solutions for the order parameter. We show that in the
resonance unitary region, where the scattering length is large, the density
profile of the soliton has a deep minimum, differently from what happens in the
BCS regime. The superfluid gap is found to be significantly quenched by the
presence of the soliton due to the occurrence of Andreev fermionic bound states
localized near the nodal plane of the order parameter.


title:
Effect of Mn substitution by Ga on the optical properties of a metallic
  manganite

abstract:
  In a metallic manganite like La(2/3)Sr(1/3)MnO(3), the substitution of Mn(+3)
by Ga(+3) dilutes the ferromagnetic order and locally cancels the Jahn-Teller
distortion, without heavily affecting the crystal structure. One can thus
follow the changes in the charge dynamics induced by Ga, until the
ferro-metallic manganite is turned into an insulator. Here this phenomenon is
studied in detail through the infrared reflectivity of five samples of
La(2/3)Sr(1/3)Mn(1-x)Ga(x)O(3), with x increasing from 0 to 0.30 and for 50 < T
< 320 K. A simple model which links the measured optical parameters to the
magnetization M(x, T) well describes the behavior of the plasma frequency, the
scattering rate, and the mid-infrared absorption along the metal-to-insulator
transition.


title:
The Geometry of Large Causal Diamonds and the No Hair Property of
  Asymptotically de-Sitter Spacetimes

abstract:
  In a previous paper we obtained formulae for the volume of a causal diamond
or Alexandrov open set $I^+(p) \cap I^-(q)$ whose duration $\tau(p,q) $ is
short compared with the curvature scale. In the present paper we obtain
asymptotic formulae valid when the point $q$ recedes to the future boundary
${\cal I}^+$ of an asymptotically de-Sitter spacetime. The volume (at fixed
$\tau$) remains finite in this limit and is given by the universal formula
$V(\tau) = {4\over 3}\pi (2\ln \cosh{\tau\over 2}-\tanh^2{\tau\over 2})$ plus
corrections (given by a series in $e^{-t_q}$) which begin at order $e^{-4t_q}$.
The coefficents of the corrections depend on the geometry of ${\cal I}^+$. This
behaviour is shown to be consistent with the no-hair property of cosmological
event horizons and with calculations of de-Sitter quasinormal modes in the
literature.


title:
Finite Schur filtration dimension for modules over an algebra with Schur
  filtration

abstract:
  Let G be GL_N or SL_N as reductive linear algebraic group over a field k of
positive characteristic p. We prove several results that were previously
established only when N < 6 or p > 2^N. Let G act rationally on a finitely
generated commutative k-algebra A. Assume that A as a G-module has a good
filtration or a Schur filtration. Let M be a noetherian A-module with
compatible G action. Then M has finite good/Schur filtration dimension, so that
there are at most finitely many nonzero H^i(G,M). Moreover these H^i(G,M) are
noetherian modules over the ring of invariants A^G. Our main tool is a
resolution involving Schur functors of the ideal of the diagonal in a product
of Grassmannians.


title:
Structure-Property Relationship in the Ordered-Perovskite- Related Oxide
  Sr3.12Er0.88Co4O10.5

abstract:
  Synchrotron X-ray diffraction patterns were measured and analyzed for a
polycrystalline sample of the room-temperature ferromagnet Sr3.12Er0.88Co4O10.5
from 300 to 650 K, from which two structural phase transitions were found to
occur successively. The higher-temperature transition at 509 K is driven by
ordering of the oxygen vacancies, which is closely related to the metallic
state at high temperatures. The lower-temperature transition at 360 K is of
first order, at which the ferromagnetic state suddenly appears with exhibiting
a jump in magnetization and resistivity. Based on the refined structure,
possible spin and orbital models for the magnetic order are proposed.


title: On the geometry of generalized Gaussian distributions

abstract:
  In this paper we consider the space of those probability distributions which
maximize the $q$-R\'enyi entropy. These distributions have the same parameter
space for every $q$, and in the $q=1$ case these are the normal distributions.
Some methods to endow this parameter space with Riemannian metric is presented:
the second derivative of the $q$-R\'enyi entropy, Tsallis-entropy and the
relative entropy give rise to a Riemannian metric, the Fisher-information
matrix is a natural Riemannian metric, and there are some geometrically
motivated metrics which were studied by Siegel, Calvo and Oller, Lovri\'c,
Min-Oo and Ruh. These metrics are different therefore our differential
geometrical calculations based on a unified metric, which covers all the above
mentioned metrics among others. We also compute the geometrical properties of
this metric, the equation of the geodesic line with some special solutions, the
Riemann and Ricci curvature tensors and scalar curvature. Using the
correspondence between the volume of the geodesic ball and the scalar curvature
we show how the parameter $q$ modulates the statistical distinguishability of
close points. We show that some frequently used metric in quantum information
geometry can be easily recovered from classical metrics.


title: Position-dependent mass models and their nonlinear characterization

abstract:
  We consider the specific models of Zhu-Kroemer and BenDaniel-Duke in a
sech$^{2}$-mass background and point out interesting correspondences with the
stationary 1-soliton and 2-soliton solutions of the KdV equation in a
supersymmetric framework.


title:
A class of bi-Hamiltonian systems associated with deformed
  Reyman-Semenov-Tian-Shansky tensors

abstract:
  This paper has been withdrawn. The authors realized that the obtained results
were not new.


title:
Molecular superfluid phase in systems of one-dimensional multicomponent
  fermionic cold atoms

abstract:
  We study a simple model of N-component fermions with contact interactions
which describes fermionic atoms with N=2F+1 hyperfine states loaded into a
one-dimensional optical lattice. We show by means of analytical and numerical
approaches that, for attractive interaction, a quasi-long-range molecular
superfluid phase emerges at low density. In such a phase, the pairing
instability is strongly suppressed and the leading instability is formed from
bound-states made of N fermions. At small density, the molecular superfluid
phase is generic and exists for a wide range of attractive contact interactions
without an SU(N) symmetry between the hyperfine states.


title: Thermal AdS(3), BTZ and competing winding modes condensation

abstract:
  We study the thermal physics of AdS(3) and the BTZ black hole when embedded
in String theory. The exact calculation of the Hagedorn temperature in TAdS(3)
is reinterpreted as the appearance of a winding tachyon both in AdS(3) and BTZ.
We construct a dual framework for analyzing the phases of the system. In this
dual framework, tachyon condensation and geometric capping appear on the same
footing, bridging the usual gap of connecting tachyon condensation to
modifications of geometry. This allows us to construct in a natural way a
candidate for the unstable phase, analogous to a small black hole in higher
dimensions. Additional peculiar effects associated with the Hagedorn
temperature and the Hawking-Page transition, some to do with the asymptotic
structure of AdS(3) and some with strong curvature effects, are analyzed and
explained.


title: An extension of the inductive approach to the lace expansion

abstract:
  We extend the inductive approach to the lace expansion, previously developed
to study models with critical dimension 4, to be applicable more generally. In
particular, the result of this note has recently been used to prove Gaussian
asymptotic behaviour for the Fourier transform of the two-point function for
sufficiently spread-out lattice trees in dimensions d>8, and it is potentially
also applicable to percolation in dimensions d>6.


title: Quasi-doubly periodic solutions to a generalized Lame equation

abstract:
  We consider the algebraic form of a generalized Lame equation with five free
parameters. By introducing a generalization of Jacobi's elliptic functions we
transform this equation to a 1-dim time-independent Schroedinger equation with
(quasi-doubly) periodic potential. We show that only for a finite set of
integral values for the five parameters quasi-doubly periodic eigenfunctions
expressible in terms of generalized Jacobi functions exist. For this purpose we
also establish a relation to the generalized Ince equation.


title: The First Stellar Cluster

abstract:
  We report results from numerical simulations of star formation in the early
universe that focus on gas at very high densities and very low metallicities.
We argue that the gas in the central regions of protogalactic halos will
fragment as long as it carries sufficient angular momentum. Rotation leads to
the build-up of massive disk-like structures which fragment to form protostars.
At metallicities Z ~ 10^-5 Zsun, dust cooling becomes effective and leads to a
sudden drop of temperature at densities above n = 10^12 cm^-3. This induces
vigorous fragmentation, leading to a very densely-packed cluster of low-mass
stars. This is the first stellar cluster. The mass function of stars peaks
below 1 Msun, similar to what is found in the solar neighborhood, and
comparable to the masses of the very-low metallicity subgiant stars recently
discovered in the halo of our Milky Way. We find that even purely primordial
gas can fragment at densities 10^14 cm^-3 < n < 10^16 cm^-3, although the
resulting mass function contains only a few objects (at least a factor of ten
less than the Z = 10^-5 Zsun mass function), and is biased towards higher
masses. A similar result is found for gas with Z = 10^-6 Zsun. Gas with Z <=
10^-6 Zsun behaves roughly isothermally at these densities (with polytropic
exponent gamma ~ 1.06) and the massive disk-like structures that form due to
angular momentum conservation will be marginally unstable. As fragmentation is
less efficient, we expect stars with Z <= 10^-6 Zsun to be massive, with masses
in excess of several tens of solar masses, consistent with the results from
previous studies.


title: An expansion for self-interacting random walks

abstract:
  We derive a perturbation expansion for general self-interacting random walks,
where steps are made on the basis of the history of the path. Examples of
models where this expansion applies are reinforced random walk, excited random
walk, the true (weakly) self-avoiding walk, loop-erased random walk, and
annealed random walk in random environment.
  In this paper we show that the expansion gives rise to useful formulae for
the speed and variance of the random walk, when these quantities are known to
exist. The results and formulae of this paper have been used elsewhere by the
authors to prove monotonicity properties for the speed (in high dimensions) of
excited random walk and related models, and certain models of random walk in
random environment.
  We also derive a law of large numbers and central limit theorem (with
explicit error terms) directly from this expansion, under strong assumptions on
the expansion coefficients. The assumptions are shown to be satisfied by
excited random walk in high dimensions with small excitation parameter, a model
of reinforced random walk with underlying drift and small reinforcement
parameter, and certain models of random walk in random environment under strong
ellipticity conditions. This is the extended version of the paper, where we
provide all proofs.


title:
Asymptotic behavior of a fourth order mean field equation with Dirichlet
  boundary condition

abstract:
  We consider asymptotic behavior of the following fourth order equation \[
\Delta^2 u= \rho \frac{e^{u}}{\int_\Om e^{u} dx} {in} \Om, u= \partial_\nu u=0
{on} \partial \Omega \] where $\Om$ is a smooth oriented bounded domain in
$\R^4$. Assuming that $0<\rho \leq C$, we completely characterize the
asymptotic behavior of the unbounded solutions.


title: Eta Photoproduction as a Test of the Extended Chiral Symmetry

abstract:
  We analyze the $\gamma p \to \eta p$ process from threshold up to 1.2 GeV,
employing an effective Lagrangian approach that allows for a mixing of eta
couplings of pseudoscalar and pseudovector nature. The mixing ratio of the
couplings may serve as a quantitative estimation of the $SU_L(3)\times SU_R(3)$
extended chiral symmetry violation in this energy regime. The data analyzed
(differential cross sections and asymmetries) show a preference for the
pseudoscalar coupling
  -- 91% of pseudoscalar coupling component for the best fit. We stress that a
more conclusive answer to this question requires a more complete
electromagnetic multipole database than the presently available one.


title:
Two-dimensional ring-like vortex and multisoliton nonlinear structures
  at the upper-hybrid resonance

abstract:
  Two-dimensional (2D) equations describing the nonlinear interaction between
upper-hybrid and dispersive magnetosonic waves are presented. Nonlocal
nonlinearity in the equations results in the possibility of existence of stable
2D nonlinear structures. A rigorous proof of the absence of collapse in the
model is given. We have found numerically different types of nonlinear
localized structures such as fundamental solitons, radially symmetric vortices,
nonrotating multisolitons (two-hump solitons, dipoles and quadrupoles), and
rotating multisolitons (azimuthons). By direct numerical simulations we show
that 2D fundamental solitons with negative hamiltonian are stable.


title:
Phase behavior of a fluid with competing attractive and repulsive
  interactions

abstract:
  Fluids in which the interparticle potential has a hard core, is attractive at
moderate separations, and repulsive at greater separations are known to exhibit
novel phase behavior, including stable inhomogeneous phases. Here we report a
joint simulation and theoretical study of such a fluid, focusing on the
relationship between the liquid-vapor transition line and any new phases. The
phase diagram is studied as a function of the amplitude of the attraction for a
certain fixed amplitude of the long ranged repulsion. We find that the effect
of the repulsion is to substitute the liquid-vapor critical point and a portion
of the associated liquid-vapor transition line, by two first order transitions.
One of these transitions separates the vapor from a fluid of spherical
liquidlike clusters; the other separates the liquid from a fluid of spherical
voids. At low temperature, the two transition lines intersect one another and a
vapor-liquid transition line at a triple point. While most integral equation
theories are unable to describe the new phase transitions, the Percus Yevick
approximation does succeed in capturing the vapor-cluster transition, as well
as aspects of the structure of the cluster fluid, in reasonable agreement with
the simulation results.


title: Towards the optimal window for the 2MASS dipole

abstract:
  A comparison of the 2MASS flux dipole to the CMB dipole can serve as a method
to constrain a combination of the cosmological parameter Omega_m and the
luminosity bias of the 2MASS survey. For this constraint to be as tight as
possible, it is necessary to maximize the correlation between the two dipoles.
This can be achieved by optimizing the survey window through which the flux
dipole is measured. Here we explicitly construct such a window for the 2MASS
survey. The optimization in essence reduces to excluding from the calculation
of the flux dipole galaxies brighter than some limiting magnitude K_min of the
near-infrared K_s band. This exclusion mitigates nonlinear effects and shot
noise from small scales, which decorrelate the 2MASS dipole from the CMB
dipole. Under the assumption of negligible shot noise we find that the optimal
value of K_min is about five. Inclusion of shot noise shifts the optimal K_min
to larger values. We present an analytical formula for shot noise for the 2MASS
flux dipole, to be used in follow-up work with 2MASS data.
  The misalignment angle between the two dipoles is a sensitive measure of
their correlation: the higher the correlation, the smaller the expectation
value of the angle. A minimum of the misalignment is thus a sign of the optimal
gravity window. We model analytically the distribution function for the
misalignment angle and show that the misalignment estimated by Maller et al. is
consistent with the assumed underlying model (though it is greater than the
expectation value). We predict with about 90% confidence that the misalignment
will decrease if 2MASS galaxies brighter than K_min = 5 mag are excluded from
the calculation of the flux dipole. This prediction has been indirectly
confirmed by the results of Erdogdu et al. (ABRIDGED)


title: A Hubble View of Star Forming Regions in the Magellanic Clouds

abstract:
  The Magellanic Clouds (MCs) offer an outstanding variety of young stellar
associations, in which large samples of low-mass stars (with masses less than 1
solar mass) currently in the act of formation can be resolved and explored
sufficiently with the Hubble Space Telescope. These pre-main sequence (PMS)
stars provide a unique snapshot of the star formation process, as it is being
recorded for the last 20 Myr, and they give important information on the
low-mass Initial Mass Function (IMF) of their host environments. We present the
latest results from observations with the Advanced Camera for Surveys (ACS) of
such star-forming regions in the MCs, and discuss the importance of Hubble}for
a comprehensive collection of substantial information on the most recent
low-mass star formation and the low-mass IMF in the MCs.


title: The Decay of Pure Quantum Turbulence in Superfluid 3He-B

abstract:
  We describe measurements of the decay of pure superfluid turbulence in
superfluid 3He-B, in the low temperature regime where the normal fluid density
is negligible. We follow the decay of the turbulence generated by a vibrating
grid as detected by vibrating wire resonators. Despite the absence of any
classical normal fluid dissipation processes, the decay is consistent with
turbulence having the classical Kolmogorov energy spectrum and is remarkably
similar to that measured in superfluid 4He at relatively high temperatures.
Further, our results strongly suggest that the decay is governed by the
superfluid circulation quantum rather than kinematic viscosity.


title: The Kerr spacetime: A brief introduction

abstract:
  This chapter provides a brief introduction to the Kerr spacetime and rotating
black holes, touching on the most common coordinate representations of the
spacetime metric and the key features of the geometry -- the presence of
horizons and ergospheres. The coverage is by no means complete, and serves
chiefly to orient oneself when reading subsequent chapters.


title:
Missing energy in black hole production and decay at the Large Hadron
  Collider

abstract:
  Black holes could be produced at the Large Hadron Collider in TeV-scale
gravity scenarios. We discuss missing energy mechanisms in black hole
production and decay in large extra-dimensional models. In particular, we
examine how graviton emission into the bulk could give the black hole enough
recoil to leave the brane. Such a perturbation would cause an abrupt
termination in Hawking emission and result in large missing-energy signatures.


title: On compositions of d.c. functions and mappings

abstract:
  A d.c. (delta-convex) function on a normed linear space is a function
representable as a difference of two continuous convex functions. We show that
an infinite dimensional analogue of Hartman's theorem on stability of d.c.
functions under compositions does not hold in general. However, we prove that
it holds in some interesting particular cases. Our main results about
compositions are proved in the more general context of d.c. mappings between
normed linear spaces.


title:
Efficient Spatial Redistribution of Quantum Dot Spontaneous Emission
  from 2D Photonic Crystals

abstract:
  We investigate the modification of the spontaneous emission dynamics and
external quantum efficiency for self-assembled InGaAs quantum dots coupled to
extended and localised photonic states in GaAs 2D-photonic crystals. The
2D-photonic bandgap is shown to give rise to a 5-10 times enhancement of the
external quantum efficiency whilst the spontaneous emission rate is
simultaneously reduced by a comparable factor. Our findings are quantitatively
explained by a modal redistribution of spontaneous emission due to the modified
local density of photonic states. The results suggest that quantum dots
embedded within 2D-photonic crystals are suitable for practical single photon
sources with high external efficiency.


title: Covering Homology

abstract:
  We introduce the notion of "covering homology" of a commutative ring spectrum
with respect to certain families of coverings of topological spaces. The
construction of covering homology is extracted from Bokstedt, Hsiang and
Madsen's topological cyclic homology. In fact covering homology with respect to
the family of orientation preserving isogenies of the circle is equal to
topological cyclic homology.
  Our basic tool for the analysis of covering homology is a cofibration
sequence involving homotopy orbits and a restriction map similar to the
restriction map used in Bokstedt, Hsiang and Madsen's construction of
topological cyclic homology.
  Covering homology with respect to families of isogenies of a torus is
constructed from iterated topological Hochschild homology. It receives a trace
map from iterated algebraic K-theory and the hope is that the rich structure,
and the calculability of covering homology will make covering homology useful
in the exploration of J. Rognes' ``red shift conjecture''.


title: Black Hole Production at the Large Hadron Collider

abstract:
  Black hole production at the Large Hadron Collider (LHC) is an interesting
consequence of TeV-scale gravity models. The predicted values, or lower limits,
for the fundamental Planck scale and number of extra dimensions will depend
directly on the accuracy of the black hole production cross-section. We give a
range of lower limits on the fundamental Planck scale that could be obtained at
LHC energies. In addition, we examine the effects of parton electric charge on
black hole production using the trapped-surface approach of general relativity.
Accounting for electric charge of the partons could reduce the black hole
cross-section by one to four orders of magnitude at the LHC.


title:
On the nature of the phase transition in the three-dimensional random
  field Ising model

abstract:
  A brief survey of the theoretical, numerical and experimental studies of the
random field Ising model during last three decades is given. Nature of the
phase transition in the three-dimensional RFIM with Gaussian random fields is
discussed. Using simple scaling arguments it is shown that if the strength of
the random fields is not too small (bigger than a certain threshold value) the
finite temperature phase transition in this system is equivalent to the
low-temperature order-disorder transition which takes place at variations of
the strength of the random fields. Detailed study of the zero-temperature phase
transition in terms of simple probabilistic arguments and modified mean-field
approach (which take into account nearest-neighbors spin-spin correlations) is
given. It is shown that if all thermally activated processes are suppressed the
ferromagnetic order parameter m(h) as the function of the strength $h$ of the
random fields becomes history dependent. In particular, the behavior of the
magnetization curves m(h) for increasing and for decreasing $h$ reveals the
hysteresis loop.


title:
Quasi-localization and quasi-mobility edge for light atoms mixed with
  heavy ones

abstract:
  A mixture of light and heavy atoms is considered. We study the kinetics of
the light atoms, scattered by the heavy ones, the latter undergoing slow
diffusive motion. In three-dimensional space we claim the existence of a
crossover region (in energy), which separates the states of the light atoms
with fast diffusion and the states with slow diffusion; the latter is
determined by the dephasing time. For the two dimensional case we have a
transition between weak localization, observed when the dephasing length is
less than the localization length (calculated for static scatterers), and
strong localization observed in the opposite case.


title:
Tight estimates for convergence of some non-stationary consensus
  algorithms

abstract:
  The present paper is devoted to estimating the speed of convergence towards
consensus for a general class of discrete-time multi-agent systems. In the
systems considered here, both the topology of the interconnection graph and the
weight of the arcs are allowed to vary as a function of time. Under the
hypothesis that some spanning tree structure is preserved along time, and that
some nonzero minimal weight of the information transfer along this tree is
guaranteed, an estimate of the contraction rate is given. The latter is
expressed explicitly as the spectral radius of some matrix depending upon the
tree depth and the lower bounds on the weights.


title: Flux Penetration in Superconducting Strip with Edge-Indentation

abstract:
  The flux penetration near a semicircular indentation at the edge of a thin
superconducting strip placed in a transverse magnetic field is investigated.
The flux front distortion due to the indentation is calculated numerically by
solving the Maxwell equations with a highly nonlinear $E(j)$ law. We find that
the excess penetration, $\Delta$, can be significantly ($\sim$ 50%) larger than
the indentation radius $r_0$, in contrast to a bulk supercondutor in the
critical state where $\Delta=r_0$. It is also shown that the flux creep tends
to smoothen the flux front, i.e. reduce $\Delta$. The results are in very good
agreement with magneto-optical studies of flux penetration into an
YBa$_2$Cu$_3$O$_x$ film having an edge defect.


title:
Classification of multiplicity free Hamiltonian actions of complex tori
  on Stein manifolds

abstract:
  A Hamiltonian action of a complex torus on a symplectic complex manifold is
said to be {\it multiplicity free} if a general orbit is a lagrangian
submanifold. To any multiplicity free Hamiltonian action of a complex torus
$T\cong (\C^\times)^n$ on a Stein manifold $X$ we assign a certain 5-tuple
consisting of a Stein manifold $Y$, an \'{e}tale map $Y\to \t^*$, a set of
divisors on $Y$ and elements of $H^2(Y,\Z)^{\oplus n}, H^2(Y,\C)$. We show that
$X$ is uniquely determined by this invariants. Furthermore, we describe all
5-tuples arising in this way.


title: Quotients of continuous convex functions on nonreflexive Banach spaces

abstract:
  On each nonreflexive Banach space X there exists a positive continuous convex
function f such that 1/f is not a d.c. function (i.e., a difference of two
continuous convex functions). This result together with known ones implies that
X is reflexive if and only if each everywhere defined quotient of two
continuous convex functions is a d.c. function. Our construction gives also a
stronger version of Klee's result concerning renormings of nonreflexive spaces
and non-norm-attaining functionals.


title:
Room-temperature ferromagnetism in nanoparticles of superconducting
  materials

abstract:
  Nanoparticles of superconducting YBa2Cu3O7-delta (YBCO) (Tc = 91 K) exhibit
ferromagnetism at room temperature while the bulk YBCO, obtained by heating the
nanoparticles at high temperature (940 degree C), shows a linear magnetization
curve. Across the superconducting transition temperature, the magnetization
curve changes from that of a soft ferromagnet to a superconductor. Furthermore,
our experiments reveal that not only nanoparticles of metal oxides but also
metal nitrides such as NbN (Tc = 6 - 12 K) and delta-MoN (Tc ~ 6 K) exhibit
room-temperature ferromagnetism.


title: Some additive applications of the isopermetric approach

abstract:
  Let $G$ be a group and let $X$ be a finite subset. The isoperimetric method
investigates the objective function $|(XB)\setminus X|$, defined on the subsets
$X$ with $|X|\ge k$ and $|G\setminus (XB)|\ge k$. A subset with minimal where
this objective function attains its minimal value is called a $k$--fragment. In
this paper we present all the basic facts about the isoperimetric method. We
improve some of our previous results and obtaingeneralizations and short proofs
for several known results. We also give some new applications. Some of the
results obtained here will be used in coming papers to improve Kempermann
structure Theory.


title:
Electromagnetic proton-neutron knockout off 16O: new achievements in
  theory

abstract:
  Results for the cross sections of the exclusive 16O(e,e'pn)14N and
16O(gamma,pn)14N knockout reactions are presented and discussed in different
kinematics. In comparison with earlier work, a complete treatment of the
center-of-mass (CM) effects in the nuclear one-body current is considered in
connection with the problem of the lack of orthogonality between initial bound
and final scattering states. The effects due to CM and orthogonalization are
investigated in combination with different treatments of correlations in the
two-nucleon overlap function and for different parametrizations of the two-body
currents. The CM effects lead in super-parallel kinematics to a dramatic
increase of the 16O(e,e'pn) cross section to the 1_2^+ excited state (3.95 MeV)
of 14N. In all the situations considered the results are very sensitive to the
treatment of correlations. A crucial role is played by tensor correlations, but
also the contribution of long-range correlations is important.


title: Results on axion physics from the CAST Experiment at CERN

abstract:
  Axions are expected to be produced in the sun via the Primakoff process. They
may be detected through the inverse process in the laboratory, under the
influence of a strong magnetic field, giving rise to X-rays of energies in the
range of a few keV. Such an Axion detector is the CERN Axion Solar Telescope
(CAST), collecting data since 2003. Results have been published, pushing the
axion-photon coupling g$_{a\gamma}$ below the 10$^{-10}$ GeV$^{-1}$ limit at
95% CL, for axion masses less than 0.02 eV. This limit is nearly an order of
magnitude lower than previous experimental limits and surpassed for the first
time limits set from astrophysical arguments based on the energy-loss concept.
The experiment is currently exploring axion masses in the range of 0.02 eV $<
m_a <$ 1.1 eV. In the next run, currently under preparation, the axion mass
explored will be extended up to the limit of 1.1 eV, testing for the first time
the region of theoretical axion models with the axion helioscope method.


title: Non-Abelian Hopf Cohomology II -- the General Case --

abstract:
  We introduce and study non-abelian cohomology sets of Hopf algebras with
coefficients in Hopf comodule algebras. We prove that these sets generalize as
well Serre's non-abelian group cohomology theory as the cohomological theory
constructed by the authors in a previous article. We establish their
functoriality and compute explicit examples. Further we classify Hopf torsors.


title:
Topologically ordered phase states: from knots and braids to quantum
  dimers

abstract:
  We consider universal statistical properties of systems that are
characterized by phase states with macroscopic degeneracy of the ground state.
A possible topological order in such systems is described by non-linear
discrete equations. We focus on the discrete equations which take place in the
case of generalized exclusion principle statistics. We show that their exact
solutions are quantum dimensions of the irreducible representations of certain
quantum group. These solutions provide an example of the point where the
generalized exclusion principle statistics and braid statistics meet each
other. We propose a procedure to construct the quantum dimer models by means of
projection of the knotted field configurations that involved braiding features
of one-dimensional topology.


title: Notes on a paper of Mess

abstract:
  These notes are a companion to the article "Lorentz spacetimes of constant
curvature" by Geoffrey Mess, which was first written in 1990 but never
published. Mess' paper will appear together with these notes in a forthcoming
issue of Geometriae Dedicata.


title: Information diffusion epidemics in social networks

abstract:
  The dynamics of information dissemination in social networks is of paramount
importance in processes such as rumors or fads propagation, spread of product
innovations or "word-of-mouth" communications. Due to the difficulty in
tracking a specific information when it is transmitted by people, most
understanding of information spreading in social networks comes from models or
indirect measurements. Here we present an integrated experimental and
theoretical framework to understand and quantitatively predict how and when
information spreads over social networks. Using data collected in Viral
Marketing campaigns that reached over 31,000 individuals in eleven European
markets, we show the large degree of variability of the participants' actions,
despite them being confronted with the common task of receiving and forwarding
the same piece of information. This have a profound effect on information
diffusion: Firstly, most of the transmission takes place due to super-spreading
events which would be considered extraordinary in population-average models.
Secondly, due to the different way individuals schedule information
transmission we observe a slowing down of the spreading of information in
social networks that happens in logarithmic time. Quantitative description of
the experiments is possible through an stochastic branching process which
corroborates the importance of heterogeneity. Since high variability of both
the intensity and frequency of human responses are found in many other
activities, our findings are pertinent to many other human driven diffusion
processes like rumors, fads, innovations or news which has important
consequences for organizations management, communications, marketing or
electronic social communities.


title: Space-Time Uncertainty and Approaches to D-Brane Field Theory

abstract:
  In connection with the space-time uncertainty principle which gives a simple
qualitative characterization of non-local or non-commutative nature of
short-distance space-time structure in string theory, author's recent
approaches toward field theories for D-branes are briefly outlined, putting
emphasis on some key ideas lying in the background. The final section of the
present report is devoted partially to a tribute to Yukawa on the occasion of
the centennial of his birth.


title:
Superdiffusion in a Model for Diffusion in a Molecularly Crowded
  Environment

abstract:
  We present a model for diffusion in a molecularly crowded environment. The
model consists of random barriers in percolation network. Random walks in the
presence of slowly moving barriers show normal diffusion for long times, but
anomalous diffusion at intermediate times. The effective exponents for square
distance versus time usually are below one at these intermediate times, but can
be also larger than one for high barrier concentrations. Thus we observe sub-
as well as super-diffusion in a crowded environment.


title: Status of the Forward Physics Projects in ATLAS

abstract:
  The ATLAS experiment at the LHC is building several detector systems for
forward physics studies and to determine the luminosity. The main forward
systems consist of a Cerenkov detector called LUCID, a Zero Degree Calorimeter
(ZDC) and Roman Pots which will house a scintillating fiber tracker system
called ALFA. Here we report some of the forward physics activities that are
foreseen in ATLAS together with the status of the related detector systems.


title: Note on operadic harmonic oscillator

abstract:
  It is explained how the time evolution of the operadic variables may be
introduced. As an example, an operadic Lax representation of the harmonic
oscillator is considered.


title:
Measurement of the complete nuclide production and kinetic energies of
  the system 136Xe + hydrogen at 1 GeV per nucleon

abstract:
  We present an extensive overview of production cross sections and kinetic
energies for the complete set of nuclides formed in the spallation of 136Xe by
protons at the incident energy of 1 GeV per nucleon. The measurement was
performed in inverse kinematics at the FRagment Separator (GSI, Darmstadt).
Slightly below the Businaro-Gallone point, 136Xe is the stable nuclide with the
largest neutron excess. The kinematic data and cross sections collected in this
work for the full nuclide production are a general benchmark for modelling the
spallation process in a neutron-rich nuclear system, where fission is
characterised by predominantly mass-asymmetric splits.


title:
Evidence for monoclinic crystal structure and negative thermal expansion
  below magnetic transition temperature in Pb(Fe_1/2Nb_1/2)O_3

abstract:
  The existing controversy about the room temperature structure of multiferroic
Pb(Fe_1/2Nb_1/2)O_3 is settled using synchrotron powder x-ray diffraction data.
Results of Rietveld refinements in the temperature range 300 to 12K reveal that
the structure remains monoclinic in the Cm space group down to 12K, but the
lattice parameters show anomalies at the magnetic transition temperature (T_N)
due to spin lattice coupling. The lattice volume exhibits negative thermal
expansion behaviour, with Alpha = - 4.64 x 10^-6 K^-1, below T_N.


title:
Emergence and resilience of cooperation in the spatial Prisoner's
  Dilemma via a reward mechanism

abstract:
  We study the problem of the emergence of cooperation in the spatial
Prisoner's Dilemma. The pioneering work by Nowak and May showed that large
initial populations of cooperators can survive and sustain cooperation in a
square lattice with imitate-the-best evolutionary dynamics. We revisit this
problem in a cost-benefit formulation suitable for a number of biological
applications. We show that if a fixed-amount reward is established for
cooperators to share, a single cooperator can invade a population of defectors
and form structures that are resilient to re-invasion even if the reward
mechanism is turned off. We discuss analytically the case of the invasion by a
single cooperator and present agent-based simulations for small initial
fractions of cooperators. Large cooperation levels, in the sustainability
range, are found. In the conclusions we discuss possible applications of this
model as well as its connections with other mechanisms proposed to promote the
emergence of cooperation.

categories: q-bio.PE math.ST nlin.AO physics.soc-ph stat.TH


title: Spherically symmetric problem on the brane and galactic rotation curves

abstract:
  We investigate the braneworld model with induced gravity to clarify the role
of the cross-over length scale \ell in the possible explanation of the
dark-matter phenomenon in astrophysics and in cosmology. Observations of the 21
cm line from neutral hydrogen clouds in spiral galaxies reveal that the
rotational velocities remain nearly constant at a value v_c ~ 10^{-3}--10^{-4}
in the units of the speed of light in the region of the galactic halo. Using
the smallness of v_c, we develop a perturbative scheme for reconstructing the
metric in a galactic halo. In the leading order of expansion in v_c, at the
distances r \gtrsim v_c \ell, our result reproduces that obtained in the
Randall-Sundrum braneworld model. This inequality is satisfied in a real spiral
galaxy such as our Milky Way for distances r ~ 3 kpc, at which the rotational
velocity curve becomes flat, v_c ~ 7 \times 10^{-4}, if \ell \lesssim 2 Mpc.
The gravitational situation in this case can be approximately described by the
Einstein equations with the so-called Weyl fluid playing the role of dark
matter. In the region near the gravitating body, we derive a closed system of
equations for static spherically symmetric situation under the approximation of
zero anisotropic stress of the Weyl fluid. We find the Schwarzschild metric to
be an approximate vacuum solution of these equations at distances r \lesssim
(r_g \ell^2)^{1/3}. The value \ell \lesssim 2 Mpc complies well with the
solar-system tests. At the same time, in cosmology, a low-density braneworld
with \ell of this order of magnitude can mimic the expansion properties of the
high-density LCDM (lambda + cold dark matter) universe at late times. Combined
observations of galactic rotation curves and gravitational lensing can possibly
discriminate between the higher-dimensional effects and dark matter.


title: Phase diagram of model anisotropic particles with octahedral symmetry

abstract:
  We computed the phase diagram for a system of model anisotropic particles
with six attractive patches in an octahedral arrangement. We chose to study
this model for a relatively narrow value of the patch width where the
lowest-energy configuration of the system is a simple cubic crystal. At this
value of the patch width, there is no stable vapour-liquid phase separation,
and there are three other crystalline phases in addition to the simple cubic
crystal that is most stable at low pressure. Firstly, at moderate pressures, it
is more favourable to form a body-centred cubic crystal, which can be viewed as
two interpenetrating, and almost non-interacting, simple cubic
lattices.Secondly, at high pressures and low temperatures, an orientationally
ordered face-centred cubic structure becomes favourable. Finally, at high
temperatures a face-centred cubic plastic crystal is the most stable solid
phase.


title: A new infinite game in Banach spaces with applications

abstract:
  We consider the following two-player game played on a separable,
infinite-dimensional Banach space X. Player S chooses a positive integer k_1
and a finite-codimensional subspace X_1 of X. Then player P chooses x_1 in the
unit sphere of X_1. Moves alternate thusly, forever. We study this game in the
following setting. Certain normalized, 1-unconditional sequences (u_i) and
(v_i) are fixed so that S has a winning strategy to force P to select x_i's so
that if the moves are (k_1,X_1,x_1,k_2,X_2,x_2,...), then (x_i) is dominated by
(u_{k_i}) and/or (x_i) dominates (v_{k_i}). In particular, we show that for
suitable (u_i) and (v_i) if X is reflexive and S can win both of the games
above, then X embeds into a reflexive space Z with an FDD which also satisfies
analogous block upper (u_i) and lower (v_i) estimates. Certain universal space
consequences ensue.


title:
The Supersymmetric Parameter Space in Light of B-physics Observables and
  Electroweak Precision Data

abstract:
  Indirect information about the possible scale of supersymmetry (SUSY)
breaking is provided by B-physics observables (BPO) as well as electroweak
precision observables (EWPO). We combine the constraints imposed by recent
measurements of the BPO BR(b -> s gamma), BR(B_s -> mu^+ mu^-), BR(B_u -> tau
nu_tau) and Delta M_{B_s} with those obtained from the experimental
measurements of the EWPO M_W, sin^2 theta_eff, Gamma_Z, (g-2)_mu and M_h,
incorporating the latest theoretical calculations of these observables within
the Standard Model and supersymmetric extensions. We perform a chi^2 fit to the
parameters of the constrained minimal supersymmetric extension of the Standard
Model (CMSSM), in which the SUSY-breaking parameters are universal at the GUT
scale, and the non-universal Higgs model (NUHM), in which this constraint is
relaxed for the soft SUSY-breaking contributions to the Higgs masses. Assuming
that the lightest supersymmetric particle (LSP) provides the cold dark matter
density preferred by WMAP and other cosmological data, we scan over the
remaining parameter space. Within the CMSSM, we confirm the preference found
previously for a relatively low SUSY-breaking scale, though there is some
slight tension between the EWPO and the BPO. In studies of some specific NUHM
scenarios compatible with the cold dark matter constraint we investigate
M_A-tan_beta planes and find preferred regions that have values of chi^2
somewhat lower than in the CMSSM.


title:
Convolution product construction of interactions in probabilistic
  physical models

abstract:
  This paper aims to give a probabilistic construction of interactions which
may be relevant for building physical theories such as interacting quantum
field theories. We start with the path integral definition of partition
function in quantum field theory which recall us the probabilistic nature of
this physical theory. From a Gaussian law considered as free theory, an
interacting theory is constructed by nontrivial convolution product between the
free theory and an interacting term which is also a probability law. The
resulting theory, again a probability law, exhibits two proprieties already
present in nowadays theories of interactions such as Gauge theory : the
interaction term does not depend on the free term, and two different free
theories can be implemented with the same interaction. The direct use of
Gaussian measures allows to generalize the present construction for infinite
dimensional spaces equipped with Gaussian measures.


title: Electron-Positron Pair Production in Relativistic Heavy Ion Collisions

abstract:
  In recent years, a large number of papers have appeared that dealt with
$\EPEM$ pair production in heavy ion collisions at high energies. To a large
extent these studies were motivated by the existence of relativistic heavy ion
accelerators all over the world. There pair production can be studied in so
called ``ultra-peripheral collisions'', where the ions do not come close enough
to interact strongly with each other. Various different methods have been used
and it is the purpose of this review to present a unified picture of the
present status of the field.


title:
Cylindrical Invisibility Cloak with Simplified Material Parameters is
  Inherently Visible

abstract:
  It was proposed that perfect invisibility cloaks can be constructed for
hiding objects from electromagnetic illumination (Pendry et al., Science 312,
p. 1780). The cylindrical cloaks experimentally demonstrated (Schurig et al.,
Science 314, p. 997) and proposed (Cai et al., Nat. Photon. 1, p. 224) have
however simplified material parameters in order to facilitate easier
realization as well as to avoid infinities in optical constants. Here we show
that the cylindrical cloaks with simplified material parameters inherently
allow the zeroth-order cylindrical wave to pass through the cloak as if the
cloak is made of a homogeneous isotropic medium, and thus visible. To all
high-order cylindrical waves, our numerical simulation suggests that the
simplified cloak inherits some properties of the ideal cloak, but finite
scatterings exist.


title: Banach spaces of bounded Szlenk index

abstract:
  For a countable ordinal a we denote by C_a the class of separable, reflexive
Banach spaces whose Szlenk index and the Szlenk index of their dual are bounded
by a. We show that each C_a admits a separable, reflexive universal space. We
also show that spaces in the class C_{omega^{a*omega}} embed into spaces of the
same class with a basis. As a consequence we deduce that each C_a is analytic
in the Effros-Borel structure of subspaces of C[0,1].


title: On the detection of very high redshift Gamma Ray Bursts with Swift

abstract:
  We compute the probability to detect long Gamma Ray Bursts (GRBs) at z>5 with
Swift, assuming that GRBs form preferentially in low-metallicity environments.
The model fits well both the observed BATSE and Swift GRB differential peak
flux distribution and is consistent with the number of z>2.5 detections in the
2-year Swift data. We find that the probability to observe a burst at z>5
becomes larger than 10% for photon fluxes P<1 ph s^{-1} cm^{-2}, consistent
with the number of confirmed detections. The corresponding fraction of z>5
bursts in the Swift catalog is ~10%-30% depending on the adopted metallicity
threshold for GRB formation. We propose to use the computed probability as a
tool to identify high redshift GRBs. By jointly considering promptly-available
information provided by Swift and model results, we can select reliable z>5
candidates in a few hours from the BAT detection. We test the procedure against
last year Swift data: only three bursts match all our requirements, two being
confirmed at z>5. Other three possible candidates are picked up by slightly
relaxing the adopted criteria. No low-z interloper is found among the six
candidates.


title: Khon-Sham Density Functional Inspired Approach to Nuclear Binding

abstract:
  A non-relativisitic nuclear density functional theory is constructed, not as
usual, from an effective density dependent nucleon-nucleon force but directly
introducing in the functional results from microscopic nuclear and neutron
matter Bruckner G-matrix calculations at various densities. A purely
phenomenological finite range part to account for surface properties is added.
The striking result is that only four to five adjustable parameters, spin-orbit
included, suffice to reproduce nuclear binding energies and radii with the same
quality as obtained with the most performant effective forces, containing on
the order of ten parameters. In this pilot work, for the pairing correlations,
simply a density dependent zero range force is adopted from the literature.
Possible future extensions of this approach are pointed out.


title: Diffusion and Relaxation Dynamics in Cluster Crystals

abstract:
  For a large class of fluids exhibiting ultrasoft bounded pair potentials,
particles form crystals consisting of clusters located in the lattice sites,
with a density-independent lattice constant. Here we present an investigation
on the dynamic features of a representative example of this class. It is found
that particles can diffuse between lattice sites, maintaining the lattice
structure, through an activated hopping mechanism. This feature yields finite
values for the diffusivity and full relaxation of density correlation
functions. Simulations suggest the existence of a localization transition which
is avoided by hopping, and a dynamic decoupling between self- and collective
correlations.


title:
Altitude and Latitude Distribution of Atmospheric Aerosol and Water
  Vapor from the Narrow-Band Lunar Eclipse Photometry

abstract:
  The work contains the description of two narrow IR-bands observational data
of total lunar eclipse of March, 3, 2007, one- and two-dimensional procedures
of radiative transfer equation solution. The results of the procedure are the
extinction values for atmospheric aerosol and water vapor at different
altitudes in the troposphere along the Earth's terminator crossing North
America, Arctic, Siberia and South-Eastern Asia. The altitude range and
possible latitude and altitude resoltion of atmosphere remote sensing by the
lunar eclipses observation are fixed. The results of water vapor retrieval are
compared with data of space experiment, the scale of vertical water vapor
distribution is found.


title: Ionized nebulae surrounding brightest cluster galaxies

abstract:
  We present IFU observations of six emission-line nebulae that surround the
central galaxy of cool core clusters. Qualitatively similar nebulae are
observed in cool core clusters even when the dynamics and possibly formation
and excitation source are different. Evidence for a nearby secondary galaxy
disturbing a nebula, as well as AGN and starburst driven outflows are presented
as possible formation mechanisms. One nebula has a rotation velocity of the
same amplitude as the underlying molecular reservoir, which implies that the
excitation or formation of a nebula does not require any disturbance of the
molecular reservoir within the central galaxy. Bulk flows and velocity shears
of a few hundred km/s are seen across all nebulae. The majority lack any
ordered rotation, their configurations are not stable so the nebulae must be
constantly reshaping, dispersing and reforming. The dimmer nebulae are
co-spatial with dust features whilst the more luminous are not. Significant
variation in the ionization state of the gas is seen in all nebulae through the
non-uniform [NII]/H_alpha ratio. There is no correlation between the line ratio
and H_alpha surface brightness, but regions with excess blue or UV light have
lower line ratios. This implies that UV from massive, young stars act in
combination with an underlying heating source that produces the observed
low-ionization spectra.


title: Rigidity of Graded Regular Algebras

abstract:
  We prove a graded version of Alev-Polo's rigidity theorem: the homogenization
of the universal enveloping algebra of a semisimple Lie algebra and the Rees
ring of the Weyl algebras $A_n(k)$ cannot be isomorphic to their fixed subring
under any finite group action. We also show the same result for other classes
of graded regular algebras including the Sklyanin algebras.


title: Winding tachyons in BTZ

abstract:
  Analysing closed string tachyon condensation will improve our understanding
of spacetime in string theory. We study the string spectrum on a BTZ black hole
spacetime supported by NS-NS flux, which provides a calculable example where we
would expect to find a quasi-localised tachyon. We find that there is a winding
tachyon when the black hole horizon is smaller than the string scale, as
expected. However, due to effects of the NS-NS B field, this tachyon is not
localised in the region where the spatial circle is string scale. We also
discuss the relation to the Milne orbifold in the limit near the singularity.


title: Rent seeking games with tax evasion

abstract:
  We consider the static and dynamic models of Cournot duopoly with tax
evasion. In the dynamic model we introduce the time delay and we analyze the
local stability of the stationary state. There is a critical value of the delay
when the Hopf bifurcation occurs.


title:
Simulation of jet quenching and high-pT particle production at RHIC and
  LHC

abstract:
  The model to simulate rescattering and partonic energy loss in
ultrarelativistic heavy ion collisions is presented. The full heavy ion event
is obtained as a superposition of a soft hydro-type state and hard multi-jets.
This model is capable of reproducing main features of the jet quenching pattern
at RHIC, and is applied to probe jet quenching in various novel channels at
LHC.


title: Les espaces de Berkovich sont excellents

abstract:
  In this paper, we first study the local rings of a Berkovich analytic space
from the point of view of commutative algebra. We show that those rings are
excellent ; we introduce the notion of a an analytically separable extension of
non-archimedean complete fields (it includes the case of the finite separable
extensions, and also the case of any complete extension of a perfect complete
non-archimedean field) and show that the usual commutative algebra properties
(Rm, Sm, Gorenstein, Cohen-Macaulay, Complete Intersection) are stable under
analytically separable ground field extensions; we also establish a GAGA
principle with respect to those properties for any finitely generated scheme
over an affinoid algebra.
  A second part of the paper deals with more global geometric notions : we
define, show the existence and establish basic properties of the irreducible
components of analytic space ; we define, show the existence and establish
basic properties of its normalization ; and we study the behaviour of
connectedness and irreducibility with respect to base change.


title: Non-propagating degrees of freedom in supergravity and very extended G_2

abstract:
  Recently a correspondence between non-propagating degrees of freedom in
maximal supergravity and the very extended algebra E_11 has been found. We
perform a similar analysis for a supergravity theory with eight supercharges
and very extended G_2. In particular, in the context of d=5 minimal
supergravity, we study whether supersymmetry can be realised on higher-rank
tensors with no propagating degrees of freedom. We find that in this case the
very extended algebra fails to capture these possibilities.


title: The conditions for quantum violation of macroscopic realism

abstract:
  Why do we not experience a violation of macroscopic realism in every-day
life? Normally, no violation can be seen either because of decoherence or the
restriction of coarse-grained measurements, transforming the time evolution of
any quantum state into a classical time evolution of a statistical mixture. We
find the sufficient condition for these classical evolutions for spin systems
under coarse-grained measurements. Then we demonstrate that there exist
"non-classical" Hamiltonians whose time evolution cannot be understood
classically, although at every instant of time the quantum spin state appears
as a classical mixture. We suggest that such Hamiltonians are unlikely to be
realized in nature because of their high computational complexity.


title: The Two-Component Afterglow of Swift GRB 050802

abstract:
  This paper investigates GRB 050802, one of the best examples of a it Swift
gamma-ray burst afterglow that shows a break in the X-ray lightcurve, while the
optical counterpart decays as a single power-law. This burst has an optically
bright afterglow of 16.5 magnitude, detected throughout the 170-650nm spectral
range of the UVOT on-board Swift. Observations began with the XRT and UVOT
telescopes 286s after the initial trigger and continued for 1.2 x 10^6s. The
X-ray lightcurve consists of three power-law segments: a rise until 420s,
followed by a slow decay with alpha_2 = 0.63 +/- 0.03 until 5000s, after which,
the lightcurve decays faster with a slope of alpha_3 = 1.59 +/- 0.03. The
optical lightcurve decays as a single power-law with alpha_O = 0.82 +/- 0.03
throughout the observation. The X-ray data on their own are consistent with the
break at 5000s being due to the end of energy injection. Modelling the optical
to X-ray spectral energy distribution, we find that the optical afterglow can
not be produced by the same component as the X-ray emission at late times,
ruling out a single component afterglow. We therefore considered two-component
jet models and find that the X-ray and optical emission is best reproduced by a
model in which both components are energy injected for the duration of the
observed afterglow and the X-ray break at 5000s is due to a jet break in the
narrow component. This bright, well-observed burst is likely a guide for
interpreting the surprising finding of Swift that bursts seldom display
achromatic jet breaks.


title: Energy weighted sums for collective excitations in nuclear Fermi-liquid

abstract:
  Model independent, $m_1$, adiabatic, $m_{-1}$, and high-energy, $m_3$, energy
weighted sums for the isoscalar and isovector nuclear excitations are
investigated within the framework of the kinetic theory adopted to the
description of a two-component nuclear Fermi-liquid. For both the adiabatic and
scaling approaches, the connection of the EWS $m_{-1}$ and $m_3$ to the nuclear
stiffness coefficients and the first- and zero-sound velocity is established.
We study the enhancement factor $\kappa_{I}$ in the energy weighted sum $m'_1$
for the isovector excitations and provide the reasonable explanation of the
experimental exceeding of the 100% exhaustion of sum $m'_1$ for the isovector
giant dipole resonances. We show the dependence of the enhancement factor
$\kappa_{I}$ on the nuclear mass number $A$ and analyse its dependence on the
Landau's isovector amplitude $F'_1$.


title: Sur la p-dimension des corps

abstract:
  Let A be an excellent integral henselian local noetherian ring, k its residue
field of characteristic p>0 and K its fraction field. Using an algebraization
technique introduced by the first named author, and the one-dimension case
already proved by Kazuya KATO, we prove the following formula: cd_p(K) = dim(A)
+ p-rank(k), if k is separably closed and K of characteristic zero. A similar
statement is valid without those assumptions on k and K.


title: Waves and instabilities in dissipative rotating superfluid neutron stars

abstract:
  We discuss wave propagation in rotating superfluid neutron star cores, taking
into account the vortex mediated mutual friction force. For models where the
two fluids co-rotate in the unperturbed state, our analysis clarifies the role
of chemical coupling and entrainment for sound and inertial waves. We also
investigate the mutual friction damping, providing results that demonstrate the
well-known fact that sound waves propagating along a vortex array are undamped.
We show that the same is not true for inertial waves, which are damped by the
mutual friction regardless of the propagation direction. We then include the
vortex tension, which arises due to local vortex curvature. Focussing on purely
transverse inertial waves, we derive the small correction that the tension
induces in the wave frequency. Finally, we allow for a relative linear flow in
the background (along the rotation axis). In this case we show how the mutual
friction coupling may induce a dynamical instability in the inertial waves. We
discuss the critical flow required for the instability to be present, its
physical interpretation and the possible relevance it may have for neutron star
physics.


title: The Thurston norm via Normal Surfaces

abstract:
  Given a triangulation of a closed, oriented, irreducible, atoroidal
3-manifold every oriented, incompressible surface may be isotoped into normal
position relative to the triangulation. Such a normal oriented surface is then
encoded by non-negative integer weights, 14 for each 3-simplex, that describe
how many copies of each oriented normal disc type there are. The Euler
characteristic and homology class are both linear functions of the weights.
There is a convex polytope in the space of weights, defined by linear equations
given by the combinatorics of the triangulation, whose image under the homology
map is the unit ball, B, of the Thurston norm.
  Applications of this approach include (1) an algorithm to compute B and hence
the Thurston norm of any homology class, (2) an explicit exponential bound on
the number of vertices of B in terms of the number of simplices in the
triangulation, (3) an algorithm to determine the fibred faces of B and hence an
algorithm to decide whether a 3-manifold fibres over the circle.


title:
The spatially resolved host of GRB 060505 and implications for the
  nature of the progenitor

abstract:
  We present a study of the host galaxy of the Gamma-Ray Burst (GRB) of May 5
2006 (GRB 060505). The host is spatially resolved in both imaging data and in a
long slit spectrum including the GRB site. We find the galaxy to be a Sbc
spiral, which is unusual for a long GRB host galaxy. The site of the GRB is
considerably different from the rest of the galaxy with intense star formation,
low metallicity and a young age. This suggest a massive stellar progenitor
rather than a merger of compact objects which has been suggested based on the
the relatively short duration of T_90=4s for the prompt emission.


title: Hamiltonian S^1 manifolds are uniruled

abstract:
  The main result of this note is that every closed Hamiltonian S^1 manifold is
uniruled, i.e. it has a nonzero Gromov--Witten invariant one of whose
constraints is a point. The proof uses the Seidel representation of \pi_1 of
the Hamiltonian group in the small quantum homology of M as well as the blow up
technique recently introduced by Hu, Li and Ruan. It applies more generally to
manifolds that have a loop of Hamiltonian symplectomorphisms with a
nondegenerate fixed maximum. Some consequences for Hofer geometry are explored.
An appendix discusses the structure of the quantum homology ring of uniruled
manifolds.


title: Fermion Generations from "Apple-Shaped" Extra Dimensions

abstract:
  We examine the behavior of fermions in the presence of an internal compact
2-manifold which in one of the spherical angles exhibits a conical character
with an obtuse angle. The extra manifold can be pictured as an apple-like
surface i.e. a sphere with an extra "wedge" insert. Such a surface has conical
singularities at north and south poles. It is shown that for this setup one can
obtain, in four dimensions, three trapped massless fermion modes which differ
from each other by having different values of angular momentum with respect to
the internal 2-manifold. The extra angular momentum acts as the family label
and these three massless modes are interpreted as the three generations of
fundamental fermions.


title:
$\R$-trees and laminations for free groups III: Currents and dual
  $\R$-tree metrics

abstract:
  This is the third of a series of three articles where we introduce
laminations for the free-groups. We explore here the link between currents and
laminations and prove that the situation is more complicated than in the
surface case of real tree dual to a measured geodesic lamination.


title:
Gradient expansion approach to nonlinear superhorizon perturbations II
  -- a single scalar field --

abstract:
  We formulate nonlinear perturbations of a scalar field dominated universe on
super-horizon scales. We consider the case of a single scalar field. We take
the gradient expansion approach. We adopt the uniform Hubble slicing and derive
the general solution valid to $O(\epsilon^2)$, where $\epsilon$ is the
expansion parameter associated with a spatial derivative, which includes both
the scalar and tensor modes. In particular, the $O(\epsilon^2)$ correction
terms to the nonlinear curvature perturbation, which become important in models
with a non-slowroll stage during inflation, are explicitly obtained.


title: A characterization of the Riesz distribution

abstract:
  Bobecka and Wesolowski (2002) have shown that, in the Olkin and Rubin
characterization of the Wishart distribution (See Casalis and Letac (1996)),
when we use the division algorithm defined by the quadratic representation and
replace the property of invariance by the existence of twice differentiable
densities, we still have a characterization of the Wishart distribution. In the
present work, we show that, when we use the division algorithm defined by the
Cholesky decomposition, we get a characterization of the Riesz distribution.


title:
Crystal isomorphisms for irreducible highest weight
  U_{v}{\hat{sl}}_{e})-modules of higher level

abstract:
  We study the crystal graphs of irreducible $U_{v}(\hat{sl}}_{e})$-modules of
higher level l. Generalizing works of the first author, we obtain a simple
description of the bijections between the classes of multipartitions which
naturally label these graphs: the Uglov multipartitions. This is achieved by
expliciting an embedding of the $U_{v}(\hat{sl}}_{e})$-crystals of level l into
$U_{v}(\hat{sl}_{\infty})$-crystals associated to highest weight modules.


title: Explicit enumeration of triangulations with multiple boundaries

abstract:
  We enumerate rooted triangulations of a sphere with multiple holes by the
total number of edges and the length of each boundary component. The proof
relies on a combinatorial identity due to W.T. Tutte.


title: Code spectrum and reliability function: Gaussian channel

abstract:
  A new approach for upper bounding the channel reliability function using the
code spectrum is described. It allows to treat both low and high rate cases in
a unified way. In particular, the earlier known upper bounds are improved, and
a new derivation of the sphere-packing bound is presented.


title: Ion transport through cell membrane channels

abstract:
  We discuss various models of ion transport through cell membrane channels.
Recent experimental data shows that sizes of ion channels are compared to those
of ions and that only few ions may be simultaneously in any single channel.
Theoretical description of ion transport in such channels should therefore take
into account interactions between ions and between ions and channel proteins.
This is not satisfied by macroscopic continuum models based on
Poisson-Nernst-Planck equations. More realistic descriptions of ion transport
are offered by microscopic Brownian and molecular dynamics. One should also
take into account a dynamical character of the channel structure. This is not
yet addressed in the literature


title: Ten Lectures on the ElectroWeak Interactions

abstract:
  Elementary particle physics is the quadrant of nature whose laws can be
written in a few lines with absolute precision and the greatest empirical
adequacy. If this is the case, as I believe it is, it must be possible and is
probably useful to introduce the students and the interested readers to the
entire subject in a compact way. This is the main aim of these Lectures.


title:
Non-Parametric Field Estimation using Randomly Deployed, Noisy, Binary
  Sensors

abstract:
  The reconstruction of a deterministic data field from binary-quantized noisy
observations of sensors which are randomly deployed over the field domain is
studied. The study focuses on the extremes of lack of deterministic control in
the sensor deployment, lack of knowledge of the noise distribution, and lack of
sensing precision and reliability. Such adverse conditions are motivated by
possible real-world scenarios where a large collection of low-cost, crudely
manufactured sensors are mass-deployed in an environment where little can be
assumed about the ambient noise. A simple estimator that reconstructs the
entire data field from these unreliable, binary-quantized, noisy observations
is proposed. Technical conditions for the almost sure and integrated mean
squared error (MSE) convergence of the estimate to the data field, as the
number of sensors tends to infinity, are derived and their implications are
discussed. For finite-dimensional, bounded-variation, and
Sobolev-differentiable function classes, specific integrated MSE decay rates
are derived. For the first and third function classes these rates are found to
be minimax order optimal with respect to infinite precision sensing and known
noise distribution.


title: Magnetic noise around metallic microstructures

abstract:
  We compute the local spectrum of the magnetic field near a metallic
microstructure at finite temperature. Our main focus is on deviations from a
plane-layered geometry for which we review the main properties. Arbitrary
geometries are handled with the help of numerical calculations based on surface
integral equations. The magnetic noise shows a significant polarization
anisotropy above flat wires with finite lateral width, in stark contrast to an
infinitely wide wire. Within the limits of a two-dimensional setting, our
results provide accurate estimates for loss and dephasing rates in so-called
`atom chip traps' based on metallic wires. A simple approximation based on the
incoherent summation of local current elements gives qualitative agreement with
the numerics, but fails to describe current correlations among neighboring
objects.


title: Guiding-fields for phase-separation: Controlling Liesegang patterns

abstract:
  Liesegang patterns emerge from precipitation processes and may be used to
build bulk structures at submicron lengthscales. Thus they have significant
potential for technological applications provided adequate methods of control
can be devised. Here we describe a simple, physically realizable
pattern-control based on the notion of driven precipitation, meaning that the
phase-separation is governed by a guiding field such as, for example, a
temperature or a pH field. The phase-separation is modeled through a
non-autonomous Cahn-Hilliard equation whose spinodal is determined by the
evolving guiding field. Control over the dynamics of the spinodal gives control
over the velocity of the instability front which separates the stable and
unstable regions of the system. Since the wavelength of the pattern is largely
determined by this velocity, the distance between successive precipitation
bands becomes controllable. We demonstrate the above ideas by numerical studies
of a 1D system with diffusive guiding field. We find that the results can be
accurately described by employing a linear stability analysis (pulled-front
theory) for determining the velocity -- local-wavelength relationship. From the
perspective of the Liesegang theory, our results indicate that the so-called
revert patterns may be naturally generated by diffusive guiding fields.

categories: cond-mat.other cond-mat.mtrl-sci cond-mat.soft nlin.PS physics.chem-ph


title: Bethe Algebra of Homogeneous XXX Heisenberg Model Has Simple Spectrum

abstract:
  We show that the algebra of commuting Hamiltonians of the homogeneous XXX
Heisenberg model has simple spectrum on the subspace of singular vectors of the
tensor product of two-dimensional $gl_2$-modules. As a byproduct we show that
there exist exactly $\binom {n}{l}-\binom{n}{l-1}$ two-dimensional vector
subspaces $V \subset \C[u]$ with a basis $f,g\in V$ such that $\deg f = l, \deg
g = n-l+1$ and $f(u)g(u-1) - f(u-1)g(u) = (u+1)^n$.


title:
Spin-charge-lattice coupling near the metal-insulator transition in
  Ca3Ru2O7

abstract:
  We report x-ray scattering studies of the c-axis lattice parameter in
Ca3Ru2O7 as a function of temperature and magnetic field. These structural
studies complement published transport and magnetization data, and therefore
elucidate the spin-charge-lattice coupling near the metal-insulator transition.
Strong anisotropy of the structural change for field applied along orthogonal
in-plane directions is observed. Competition between a spin-polarized phase
that does not couple to the lattice, and an antiferromagnetic metallic phase,
which does, gives rise to rich behavior for B $\parallel$ b.


title: Maximal slope of tensor product of Hermitian vector bundles

abstract:
  We give an upper bound for the maximal slope of the tensor product of several
non-zero Hermitian vector bundles on the spectrum of an algebraic integer ring.
By Minkowski's theorem, we need to estimate the Arakelov degree of an arbitrary
Hermitian line subbundle $\bar M$ of the tensor product. In the case where the
generic fiber of $M$ is semistable in the sense of geometric invariant theory,
the estimation is established by constructing, through the classical invariant
theory, a special polynomial which does not vanish on the generic fibre of $M$.
Otherwise we use an explicte version of a result of Ramanan and Ramanathan to
reduce the general case to the former one.


title:
Irreducible forms for the metric variations of the action terms of
  sixth-order gravity and approximated stress-energy tensor

abstract:
  We provide irreducible expressions for the metric variations of the
gravitational action terms constructed from the 17 curvature invariants of
order six in derivatives of the metric tensor i.e. from the geometrical terms
appearing in the diagonal heat-kernel or Gilkey-DeWitt coefficient $a_3$. We
then express, for a four dimensional spacetime, the approximated stress-energy
tensor constructed from the renormalized DeWitt-Schwinger effective action
associated with a massive scalar field. We also construct, for higher
dimensional spacetimes, the infinite counterterms of order six in derivatives
of the metric tensor appearing in the left hand side of Einstein equations as
well as the contribution associated with the cubic Lovelock gravitational
action. In an appendix, we provide a list of geometrical relations we have used
and which are more generally helpful for calculations in two-loop quantum
gravity in a four dimensional background or for calculations in one-loop
quantum gravity in higher dimensional background. We also obtain the
approximated stress-energy tensors associated with a massive spinor field and a
massive vector field propagating in a four dimensional background.


title:
Probabilistic Interval Temporal Logic and Duration Calculus with
  Infinite Intervals: Complete Proof Systems

abstract:
  The paper presents probabilistic extensions of interval temporal logic (ITL)
and duration calculus (DC) with infinite intervals and complete Hilbert-style
proof systems for them. The completeness results are a strong completeness
theorem for the system of probabilistic ITL with respect to an abstract
semantics and a relative completeness theorem for the system of probabilistic
DC with respect to real-time semantics. The proposed systems subsume
probabilistic real-time DC as known from the literature. A correspondence
between the proposed systems and a system of probabilistic interval temporal
logic with finite intervals and expanding modalities is established too.


title:
Extending the reach of axion-photon regeneration experiments towards
  larger masses with phase shift plates

abstract:
  We present a scheme to extend the sensitivity of axion-photon regeneration
experiments towards larger masses with the help of properly chosen and placed
phase shift plates.