title:
Manifold algorithmic errors in quantum computers with static internal
  imperfections

abstract:
  The inevitable existence of static internal imperfections and residual
interactions in some quantum computer architectures result in internal
decoherence, dissipation, and destructive unitary shifts of active algorithms.
By exact numerical simulations we determine the relative importance and origin
of these errors for a Josephson charge qubit quantum computer. In particular we
determine that the dynamics of a CNOT gate interacting with its idle
neighboring qubits via native residual coupling behaves much like a perturbed
kicked top in the exponential decay regime, where fidelity decay is only weakly
dependent on perturbation strength. This means that retroactive removal of gate
errors (whether unitary or non-unitary) may not be possible, and that effective
error correction schemes must operate concurrently with the implementation of
subcomponents of the gate.


title:
Condition for emergence of complex eigenvalues in the Bogoliubov-de
  Gennes equations

abstract:
  The condition for the appearance of dynamical instability of the
Bose-condensed system, characterized by the emergence of complex eigenvalues in
the Bogoliubov-de Gennes equations, is studied analytically. We perturbatively
expand both the Gross-Pitaevskii and Bogoliubov-de Gennes equations with
respect to the coupling constant. It is concluded that the degeneracy between a
positive-norm eigenmode and a negative-norm one is essential for the emergence
of complex modes. Based on the conclusion, we justify the two-mode
approximation applied in our previous work [E. Fukuyama \textit{et al}., Phys.
Rev. A {\bf 76}, 043608 (2007)], in which we analytically studied the condition
for the existence of complex modes when the condensate has a highly quantized
vortex.


title:
Single photon Michelson-Morley experiment via de Broglie-Bohm picture:
  An interpretation based on the hypothesis of frame dragging

abstract:
  The Michelson-Morley experiment is considered via a single photon
interferometer and a hypothesis of the dragging of the permittivity of free
space and permeability of free space. The Michelson-Morley experimental results
can be interpreted using de Broglie-Bohm picture. In the global positioning
system (GPS) experiment, isotropic constancy of the speed of light, c, was
confirmed by direct one way measurement. That is, Michelson-Morley experiments
without interference are confirmed every day; therefore the hypothesis of frame
dragging is a suitable explanation of the Michelson-Morley experimental
results.


title: Existence of broken Lefschetz fibrations

abstract:
  We prove that every closed oriented smooth 4-manifold X admits a broken
Lefschetz fibration (aka singular Lefschetz fibration) over the 2-sphere. Given
any closed orientable surface F of square zero in X, we can choose the
fibration so that F is a fiber. Moreover, we can arrange it so that there is
only one Lefschetz critical point when the Euler characteristic e(X) is odd,
and none when e(X) is even. We make use of topological modifications of smooth
maps with fold and cusp singularities due to Saeki and Levine, and thus we get
alternative proofs of previous existence results. Also shown is the existence
of broken Lefschetz pencils with connected fibers on any near-symplectic
4-manifold.


title:
Statistical and dynamical aspects in the decay of hot neutron-rich
  nuclei

abstract:
  The signal of isospin-asymmetric phase transition in the evolution of the
chemical potential was observed for hot quasi-projectiles produced in the
reactions 40,48Ca + 27Al confirming an analogous observation in the lighter
system 28Si + 112,124Sn. With increasing mass, the properties of hot
quasi-projectiles become increasingly influenced by the secondary emission.
Thermodynamical observables exhibit no sensitivity to the different number of
missing neutrons in the two reactions 40,48Ca + 27Al, thus providing a signal
of dynamical emission of neutrons, which can be related to formation of a very
neutron-rich low-density region (neck) between the projectile and target.


title: Quantum Forbidden-Interval Theorems for Stochastic Resonance

abstract:
  We extend the classical forbidden-interval theorems for a
stochastic-resonance noise benefit in a nonlinear system to a quantum-optical
communication model and a continuous-variable quantum key distribution model.
Each quantum forbidden-interval theorem gives a necessary and sufficient
condition that determines whether stochastic resonance occurs in quantum
communication of classical messages. The quantum theorems apply to any quantum
noise source that has finite variance or that comes from the family of
infinite-variance alpha-stable probability densities. Simulations show the
noise benefits for the basic quantum communication model and the
continuous-variable quantum key distribution model.


title:
Generating Initial Data in General Relativity using Adaptive Finite
  Element Methods

abstract:
  The conformal formulation of the Einstein constraint equations is first
reviewed, and we then consider the design, analysis, and implementation of
adaptive multilevel finite element-type numerical methods for the resulting
coupled nonlinear elliptic system. We derive weak formulations of the coupled
constraints, and review some new developments in the solution theory for the
constraints in the cases of constant mean extrinsic curvature (CMC) data,
near-CMC data, and arbitrarily prescribed mean extrinsic curvature data. We
then outline some recent results on a priori and a posteriori error estimates
for a broad class of Galerkin-type approximation methods for this system which
includes techniques such as finite element, wavelet, and spectral methods. We
then use these estimates to construct an adaptive finite element method (AFEM)
for solving this system numerically, and outline some new convergence and
optimality results. We then describe in some detail an implementation of the
methods using the FETK software package, which is an adaptive multilevel finite
element code designed to solve nonlinear elliptic and parabolic systems on
Riemannian manifolds. We finish by describing a simplex mesh generation
algorithm for compact binary objects, and then look at a detailed example
showing the use of FETK for numerical solution of the constraints.


title: Exact Ground States of Large Two-Dimensional Planar Ising Spin Glasses

abstract:
  Studying spin-glass physics through analyzing their ground-state properties
has a long history. Although there exist polynomial-time algorithms for the
two-dimensional planar case, where the problem of finding ground states is
transformed to a minimum-weight perfect matching problem, the reachable system
sizes have been limited both by the needed CPU time and by memory requirements.
In this work, we present an algorithm for the calculation of exact ground
states for two-dimensional Ising spin glasses with free boundary conditions in
at least one direction. The algorithmic foundations of the method date back to
the work of Kasteleyn from the 1960s for computing the complete partition
function of the Ising model. Using Kasteleyn cities, we calculate exact ground
states for huge two-dimensional planar Ising spin-glass lattices (up to
3000x3000 spins) within reasonable time. According to our knowledge, these are
the largest sizes currently available. Kasteleyn cities were recently also used
by Thomas and Middleton in the context of extended ground states on the torus.
Moreover, they show that the method can also be used for computing ground
states of planar graphs. Furthermore, we point out that the correctness of
heuristically computed ground states can easily be verified. Finally, we
evaluate the solution quality of heuristic variants of the Bieche et al.
approach.


title: Prerequisite for superconductivity: appropriate spin-charge correlations

abstract:
  This work investigates the relation between superconductivity and
correlations. A simple calculation shows that the appropriate spin-charge
correlation is the key role to any superconductivity, and this calculation is
consistent with the analyses of unusual properties of superconductors. (Note:
the Tc of this model is not given clearly in this work, but we have advanced
this mechanism to a t-x model which includes various superconductivities and
magnetisms (please see arXiv:0707.3660 and following works).)


title: Approximate word matches between two random sequences

abstract:
  Given two sequences over a finite alphabet $\mathcal{L}$, the $D_2$ statistic
is the number of $m$-letter word matches between the two sequences. This
statistic is used in bioinformatics for expressed sequence tag database
searches. Here we study a generalization of the $D_2$ statistic in the context
of DNA sequences, under the assumption of strand symmetric Bernoulli text. For
$k<m$, we look at the count of $m$-letter word matches with up to $k$
mismatches. For this statistic, we compute the expectation, give upper and
lower bounds for the variance and prove its distribution is asymptotically
normal.


title:
Two-loop additive mass renormalization with clover fermions and Symanzik
  improved gluons

abstract:
  We calculate the critical value of the hopping parameter, $\kappa_c$, in
Lattice QCD, up to two loops in perturbation theory. We employ the
Sheikholeslami-Wohlert (clover) improved action for fermions and the Symanzik
improved gluon action with 4- and 6-link loops.
  The quantity which we study is a typical case of a vacuum expectation value
resulting in an additive renormalization; as such, it is characterized by a
power (linear) divergence in the lattice spacing, and its calculation lies at
the limits of applicability of perturbation theory.
  Our results are polynomial in $c_{SW}$ (clover parameter) and cover a wide
range of values for the Symanzik coefficients $c_i$. The dependence on the
number of colors N and the number of fermion flavors $N_f$ is shown explicitly.
In order to compare our results to non perturbative evaluations of $\kappa_c$
coming from Monte Carlo simulations, we employ an improved perturbation theory
method for improved actions.


title: From k-SAT to k-CSP: Two Generalized Algorithms

abstract:
  Constraint satisfaction problems (CSPs) models many important intractable
NP-hard problems such as propositional satisfiability problem (SAT). Algorithms
with non-trivial upper bounds on running time for restricted SAT with bounded
clause length k (k-SAT) can be classified into three styles: DPLL-like,
PPSZ-like and Local Search, with local search algorithms having already been
generalized to CSP with bounded constraint arity k (k-CSP). We generalize a
DPLL-like algorithm in its simplest form and a PPSZ-like algorithm from k-SAT
to k-CSP. As far as we know, this is the first attempt to use PPSZ-like
strategy to solve k-CSP, and before little work has been focused on the
DPLL-like or PPSZ-like strategies for k-CSP.


title:
Structural transition of force chains observed by mechanical
  spectroscopy

abstract:
  The dissipation properties of a fine sand system are investigated by a
low-frequency mechanical spectroscopy. The experiments show many interesting
profiles of the relative energy dissipation, which imply that some structural
transition of force chains in dense granular media has occurred. The following
data and discussion indicate that the transition of force chains will lead to
the small deformation of arrangement in the granular system, which is
responsible for the historical effects. We hope this research can improve our
knowledge of the microstructure of the granular materials.


title: Is the phase of plane waves a frame-independent quantity?

abstract:
  The invariance of the phase of plane waves among inertial frames is
investigated in some details. The reason that eventually led the author of a
recent EPL letter [EPL \textbf{79}, 1006 (2007)] to a spurious conclusion of
the non-invariance of the phase of waves has been identified -- it is the
ignorance of the effect of relativistically-induced optical anisotropy in the
analysis of the problem. It is argued that the Lorentz-invariant expression for
the phase of waves should be taken in the form $\Phi=\mathbf{k\cdot
r}-\mathbf{k\cdot u}/c$, instead of the widely-used expression
$\Phi=\mathbf{k\cdot r}-\omega t$ which has a limited validity.


title:
Multi-wavelength (radio, X-ray and gamma-ray) observations of the
  gamma-ray binary LS I +61 303

abstract:
  We present the results of the first multiwavelength observing campaign on the
high-mass X-ray binary LS I +61 303 comprising observations at the TeV regime
with the MAGIC telescope, along with X-ray observations with Chandra, and radio
interferometric observations with the MERLIN, EVN and VLBA arrays, in October
and November 2006. From our MERLIN observations, we can exclude the existence
of large scale (~100 mas) persistent radio-jets. Our 5.0 GHz VLBA observations
display morphological similarities to previous 8.4 GHz VLBA observations
carried out at the same orbital phase, suggesting a high level of periodicity
and stability of the processes behind the radio emission. This makes it
unlikely that variability of the radio emission is due to the interaction of an
outflow with variable wind clumps. If the radio emission is produced by a
milliarcsecond scale jet, it should also show a stable, periodic behavior. It
is then difficult to reconcile the absence of a large scale jet (~100 mas) in
our observations with the evidence of a persistent relativistic jet reported
previously. We find a possible hint of temporal correlation between the X-ray
and TeV emissions and evidence for radio/TeV non-correlation, which points to
the existence of one population of particles producing the radio emission and a
different one producing the X-ray and TeV emissions. Finally, we present a
quasi-simultaneous energy spectrum including radio, X-ray and TeV bands.


title: Evidence of low-dimensional chaos in magnetized plasma turbulence

abstract:
  We analyze probe data obtained from a toroidal magnetized plasma
configuration suitable for studies of low-frequency gradient-driven
instabilities. These instabilities give rise to field-aligned convection rolls
analogous to Rayleigh-Benard cells in neutral fluids, and may theoretically
develop similar routes to chaos. When using mean-field dimension analysis, we
observe low dimensionality, but this could originate from either
low-dimensional chaos, periodicity or quasi-periodicity. Therefore, we apply
recurrence plot analysis as well as estimation of the largest Lyapunov
exponent. These analyses provide evidence of low-dimensional chaos, in
agreement with theoretical predictions.


title: Electronic structure of GdN, and the influence of exact exchange

abstract:
  GdN bulk is studied with the local density approximation, on the Hartree-Fock
level, and on the level of the hybrid functional B3LYP. A local basis set
formalism is used, as implemented in the present CRYSTAL06 release. It is
demonstrated that the code is technically capable of treating this system with
its 4f electrons explicitly, i.e. out of the core. The band structure at the
level of the local density approximation is in good agreement with earlier
calculations and is found to be half-metallic. The Hartree-Fock band structure
is insulating with a large gap. Interestingly, three solutions were found at
the B3LYP level. The lowest of them is insulating for majority spin, and the
Fermi surface for minority spin consists only of points, resulting in a very
low density of states around the Fermi level.


title: Remarks on 1-motivic sheaves

abstract:
  We generalize the construction of the category of 1-motives with torsion
${}^tM_1$ (introduced by Barbieri-Viale, Rosenschon and Saito) as well as the
construction of the category of 1-motivic sheaves ${\rm Shv}_1$ (defined by
Barbieri-Viale and Kahn) to perfect fields $k$ (without inverting the
exponential characteristic). For $k$ transcendental over the prime field we
extend a result of Barbieri-Viale and Kahn, showing that ${}^tM$ and ${\rm
Shv}_1$ have equivalent bounded derived categories.


title:
Number squeezing, quantum fluctuations and oscillations in mesoscopic
  Bose Josephson junctions

abstract:
  Starting from a quantum two-mode Bose-Hubbard Hamiltonian we determine the
ground state properties, momentum distribution and dynamical evolution for a
Bose Josephson junction realized by an ultracold Bose gas in a double-well
trap. Varying the well asymmetry we identify Mott-like regions of parameters
where number fluctuations are suppressed and the interference fringes in the
momentum distribution are strongly reduced. We also show how Schroedinger cat
states, realized from an initially phase coherent state by a sudden rise of the
barrier among the two wells, will give rise to a destructive interference in
the time-dependent momentum distribution.


title: Poisson suspensions and entropy for infinite transformations

abstract:
  The Poisson entropy of an infinite-measure-preserving transformation is
defined as the Kolmogorov entropy of its Poisson suspension. In this article,
we relate Poisson entropy with other definitions of entropy for infinite
transformations: For quasi-finite transformations we prove that Poisson entropy
coincides with Krengel's and Parry's entropy. In particular, this implies that
for null-recurrent Markov chains, the usual formula for the entropy $-\sum q_i
p_{i,j}\log p_{i,j}$ holds in any of the definitions for entropy. Poisson
entropy dominates Parry's entropy in any conservative transformation. We also
prove that relative entropy (in the sense of Danilenko and Rudolph) coincides
with the relative Poisson entropy. Thus, for any factor of a conservative
transformation, difference of the Krengel's entropy is equal to the difference
of the Poisson entropies. In case there exists a factor with zero Poisson
entropy, we prove the existence of a maximum (Pinsker) factor with zero Poisson
entropy. Together with the preceding results, this answers affirmatively the
question raised in arXiv:0705.2148v3 about existence of a Pinsker factor in the
sense of Krengel for quasi-finite transformations.


title: Renormalization group in difference systems

abstract:
  A new singular perturbation method based on the Lie symmetry group is
presented to a system of difference equations. This method yields consistent
derivation of a renormalization group equation which gives an asymptotic
solution of the difference equation. The renormalization group equation is a
Lie differential equation of a Lie group which leaves the system approximately
invariant. For a 2-D symplectic map, the renormalization group equation becomes
a Hamiltonian system and a long-time behaviour of the symplectic map is
described by the Hamiltonian. We study the Poincar\'e-Birkoff bifurcation in
the 2-D symplectic map by means of the Hamiltonian and give a condition for the
bifurcation.


title:
Adaptive thresholding estimation of a Poisson intensity with infinite
  support

abstract:
  The purpose of this paper is to estimate the intensity of a Poisson process
$N$ by using thresholding rules. In this paper, the intensity, defined as the
derivative of the mean measure of $N$ with respect to $ndx$ where $n$ is a
fixed parameter, is assumed to be non-compactly supported. The estimator
$\tilde{f}_{n,\gamma}$ based on random thresholds is proved to achieve the same
performance as the oracle estimator up to a logarithmic term. Oracle
inequalities allow to derive the maxiset of $\tilde{f}_{n,\gamma}$. Then,
minimax properties of $\tilde{f}_{n,\gamma}$ are established. We first prove
that the rate of this estimator on Besov spaces ${\cal B}^\al_{p,q}$ when
$p\leq 2$ is $(\ln(n)/n)^{\al/(1+2\al)}$. This result has two consequences.
First, it establishes that the minimax rate of Besov spaces ${\cal
B}^\al_{p,q}$ with $p\leq 2$ when non compactly supported functions are
considered is the same as for compactly supported functions up to a logarithmic
term. This result is new. Furthermore, $\tilde{f}_{n,\gamma}$ is adaptive
minimax up to a logarithmic term. When $p>2$, the situation changes
dramatically and the rate of $\tilde{f}_{n,\gamma}$ on Besov spaces ${\cal
B}^\al_{p,q}$ is worse than $(\ln(n)/n)^{\al/(1+2\al)}$. Finally, the random
threshold depends on a parameter $\gamma$ that has to be suitably chosen in
practice. Some theoretical results provide upper and lower bounds of $\gamma$
to obtain satisfying oracle inequalities. Simulations reinforce these results.


title:
Precision measurements with polar molecules: the role of the black body
  radiation

abstract:
  In the perspective of the outstanding developments of high-precision
measurements of fundamental constants using polar molecules related to ultimate
checks of fundamental theories, we investigate the possibly counterproductive
role of black-body radiation on a series of diatomic molecules which would be
trapped and observed for long durations. We show that the absorption of
black-body radiation at room temperature may indeed limit the lifetime of
trapped molecules prepared in a well-defined quantum state. Several examples
are treated, corresponding to pure rotational absorption, pure vibrational
absorption or both. We also investigate the role of a black-body
radiation-induced energy shift on molecular levels and how it could affect
high-precision frequency measurements.


title: Fast switchable electro-optic radial polarization retarder

abstract:
  A fast, switchable electro-optic radial polarization retarder (EO-RPR)
fabricated using the electro-optic ceramic PMN-PT is presented. This EO-RPR is
useful for fast, switchable generation of pure cylindrical vector beam. When
used together with a pair of half-wave plates, the EO-RPR can change circularly
polarized light into any cylindrical vector beam of interest such as radially
or azimuthally polarized light. Radially and azimuthally polarized light with
purities greater than 95% are generated experimentally. The advantages of using
EO-RPR include fast response times, low driving voltage and transparency in a
wide spectral range (500 -7000 nm).


title:
Electronic structure induced reconstruction and magnetic ordering at the
  LaAlO$_3|$SrTiO$_3$ interface

abstract:
  Using local density approximation (LDA) calculations we predict
GdFeO$_3$-like rotation of TiO$_6$ octahedra at the $n$-type interface between
LaAlO$_3$ and SrTiO$_3$. The narrowing of the Ti $d$ bandwidth which results
means that for very modest values of $U$, LDA$+U$ calculations predict charge
and spin ordering at the interface. Recent experimental evidence for magnetic
interface ordering may be understood in terms of the close proximity of an
antiferromagnetic insulating ground state to a ferromagnetic metallic excited
state.


title: Beam propagation in finite size photonic crystals and metamaterials

abstract:
  The recent interest in the imaging possibilities of photonic crystals
(superlensing, superprism, optical mirages etc...) call for a detailed analysis
of beam propagation inside a finite periodic structure. In this paper, an
answer to the question "where does the beam emerge?" is given. Contrarily to
common knowledge, it is not always true that the shift of a beam is given by
the normal to the dispersion curve. This phenomenon is explained in terms of
evanescent waves and a renormalized diagram that gives the correct direction is
given.


title:
The wetting problem of fluids on solid surfaces: Dynamics of lines and
  contact angle hysteresis

abstract:
  In 1805, Young was the first who introduced an expression for contact angle
in static, but today, the motion of the contact-line formed at the intersection
of two immiscible fluids and a solid is still subject to dispute. By means of
the new physical concept of line viscosity, the equations of motions and
boundary conditions for fluids in contact on a solid surface together with
interface and contact-line are revisited. A new Young-Dupr\'e equation for the
dynamic contact angle is deduced. The interfacial energies between fluids and
solid take into account the chemical heterogeneities and the solid surface
roughness. A scaling analysis of the microscopic law associated with the
Young-Dupr\'e dynamic equation allows us to obtain a new macroscopic equation
for the motion of the contact-line. Here we show that our theoretical
predictions fit perfectly together with the contact angle hysteresis phenomenon
and the experimentally well-known results expressing the dependence of the
dynamic contact angle on the celerity of the contact-line. We additively get a
quantitative explanation for the maximum speed of wetting (and dewetting).


title: Anti-de Sitter Quotients: When Are They Black Holes?

abstract:
  We point out that the BTZ black holes, and their relatives, can be defined in
a cleaner way than they originally were. The covering space can be taken to be
anti-de Sitter space, period, while scri splits up into components due to
Misner singularities. Our definition permits us to choose between two
conflicting claims concerning BTZ black holes in 3+1 dimensions.


title: Dark Energy From Fifth Dimension

abstract:
  Observational evidence for the existence of dark energy is strong. Here we
suggest a model which is based on a modified gravitational theory in 5D and
interpret the 5th dimension as a manifestation of dark energy in the 4D
observable universe. We also obtain an equation of state parameter which varies
with time. Finally, we match our model with observations by choosing the free
parameters of the model.


title:
The appearance of magnetospheric instability in flaring activity at the
  onset of X-ray outbursts in A0535+26

abstract:
  We argue that X-ray flaring variability observed in the transient X-ray
pulsar A 0535+26 is due to low-mode magnetospheric instability. This
instability develops at the onset of accretion, in the thin boundary layer
between the accretion disk and neutron star magnetosphere. As a result, the
matter collected in the boundary layer can rapidly fall onto the NS surface
close to the magnetic poles, but not exactly along the field lines by which the
stationary accretion proceeds. This explains the shift in cyclotron line energy
measured using RXTE data in a pre-outburst spike, with respect to the line
energy observed during the main outburst. Furthermore, the instability can
account for the difference in pulse profiles, and their energy evolution that
is different in the pre-outburst flare and main outburst.


title:
Polygones de Hodge, de Newton et de l'inertie mod\'er\'ee des
  repr\'esentations semi-stables

abstract:
  Let k be a perfect field, and K be a totally ramified extension of K_0 = Frac
W(k) of degree e. To a semi-stable p-adic representation of G_K (the absolute
Galois group of K), one can classicaly associate two polygons : the Hodge
polygon et the Newton polygon. It is well known that the former lies below the
latter, and that they have same endpoints. In this note, we introduce a third
polygon gotten from the semi-simplification of the representation mod p, and,
under some conditions on Hodge-Tate weights, we prove that it lies above the
Hodge polygon again with same endpoint. We finally examine one exemple
associated to a crystalline representation.


title: The pre-outburst flare of the A 0535+26 August/September 2005 outburst

abstract:
  We study the spectral and temporal behavior of the High Mass X-ray Binary A
0535+26 during a `pre-outburst flare' which took place ~5 d before the peak of
a normal (type I) outburst in August/September 2005. We compare the studied
behavior with that observed during the outburst. We analyse RXTE observations
that monitored A 0535+26 during the outburst. We complete spectral and timing
analyses of the data. We study the evolution of the pulse period, present
energy-dependent pulse profiles both at the initial pre-outburst flare and
close to outburst maximum, and measure how the cyclotron resonance-scattering
feature (hereafter CRSF) evolves. We present three main results: a constant
period P=103.3960(5)s is measured until periastron passage, followed by a
spin-up with a decreasing period derivative of Pdot=(-1.69+/-0.04)x10^(-8)s/s
at MJD 53618, and P remains constant again at the end of the main outburst. The
spin-up provides evidence for the existence of an accretion disk during the
normal outburst. We measure a CRSF energy of Ecyc~50kev during the pre-outburst
flare, and Ecyc~46kev during the main outburst. The pulse shape, which varies
significantly during both pre-outburst flare and main outburst, evolves
strongly with photon energy.


title:
Representative statistical ensembles for Bose systems with broken gauge
  symmetry

abstract:
  Bose-condensed systems with broken global gauge symmetry are considered. The
description of these systems, as has been shown by Hohenberg and Martin,
possesses an internal inconsistency, resulting in either nonconserving theories
or yielding an unphysical gap in the spectrum. The general notion of
representative statistical ensembles is formulated for arbitrary statistical
systems, equilibrium or not. The principal idea of this notion is the necessity
of taking into account all imposed conditions that uniquely define the given
statistical system. Employing such a representative ensemble for Bose-condensed
systems removes all paradoxes, yielding a completely self-consistent theory,
both conserving and gapless in any approximation. This is illustrated for an
equilibrium uniform Bose system.


title: A Subhalo-Galaxy Correspondence Model of Galaxy Formation

abstract:
  We propose a model of allocating galaxies in cosmological N-body simulations.
we identify each subhalo with a galaxy, and assign luminosity and morphological
type assuming that the galaxy luminosity is a monotonic function of its host
subhalo mass. The morphology assignment is made by using two simple relations
between subhalo mass and galaxy luminosity of different types. One is using a
constant ratio in luminosity of early (E/SO) and late (S/Irr) type galaxies at
a fixed subhalo mass. And the other assumes that galaxies of different
morphological types but having an equal luminosity have a constant ratio in
their subhalo masses. We made a series of comparisons of the properties of
these simulated galaxies with those of the SDSS galaxies. The resulting
simulated galaxy sample is found to successfully reproduce the observed local
number density distribution except for in high density regions. The luminosity
function is studied as a function of local density. It was found that the
observed luminosity functions in different local density environments are
overall well-reproduced by the simulated galaxies. Discrepancy is found at the
bright end of the luminosity function of early types in the underdense regions
and at the faint end of both morphological types in very high density regions.
A significant fraction of the observed early type galaxies in voids seems to
have undergone a relatively recent star formation and became brighter. The lack
of faint simulated galaxies in dense regions may be due to the strong tidal
force of the central halo which destroys less massive satellite subhalos around
in the simulation. The mass-to-light ratio is found to depend on the local
density in the way similar to that observed in the SDSS sample. (abridged)


title: Renormalization of gauge fields using Hopf algebras

abstract:
  We describe the Hopf algebraic structure of Feynman graphs for non-abelian
gauge theories, and prove compatibility of the so-called Slavnov-Taylor
identities with the coproduct. When these identities are taken into account,
the coproduct closes on the Green's functions, which thus generate a Hopf
subalgebra.


title:
An efficient and accurate method to obtain the energy-dependent Green
  function for general potentials

abstract:
  Time-dependent quantum mechanics provides an intuitive picture of particle
propagation in external fields. Semiclassical methods link the classical
trajectories of particles with their quantum mechanical propagation. Many
analytical results and a variety of numerical methods have been developed to
solve the time-dependent Schroedinger equation. The time-dependent methods work
for nearly arbitrarily shaped potentials, including sources and sinks via
complex-valued potentials. Many quantities are measured at fixed energy, which
is seemingly not well suited for a time-dependent formulation. Very few methods
exist to obtain the energy-dependent Green function for complicated potentials
without resorting to ensemble averages or using certain lead-in arrangements.
Here, we demonstrate in detail a time-dependent approach, which can accurately
and effectively construct the energy-dependent Green function for very general
potentials. The applications of the method are numerous, including chemical,
mesoscopic, and atomic physics.


title:
Constraints on Primordial Black Holes by Distortions of Cosmic Microwave
  Background

abstract:
  Possible influence of primordial black hole (PBH) evaporations on cosmic
microwave background (CMB) is investigated. The spectrum distortions of CMB
from the black-body spectrum are described by the chemical potential $\mu$ and
the Compton parameter $y$. From COBE/FIRAS limits on $\mu$ and $y$, the power
law index $n$ of primordial density fluctuations and the mass fraction of PBHs
$\beta$ are constrained by employing the peak theory for the formation process
of PBHs. Constraints set here are $n < 1.304$ and $n<1.333$ in the thresholds
of peaks $\zeta_{\rm th} =0.7$ and $\zeta_{\rm th} =1.2$, respectively, for the
PBH mass range between $2.7\times 10^{11}$g and $1.6 \times 10^{12}$g, and $n <
1.312$ and $n<1.343$ in the thresholds of peaks $\zeta_{\rm th} =0.7$ and
$\zeta_{\rm th} =1.2$, respectively, for the PBH mass range between $1.6 \times
10^{12} {\rm g}$ and $3.5\times 10^{13}$g, which correspond to the comoving
scales between $3 \times 10^{-18}$Mpc and $ 4\times 10^{-17}$Mpc. The
constraint on the PBH fraction, which is the direct probe of the amplitude of
density fluctuations in these scales, stays an almost same value as
$\beta<10^{-21}$ in these mass ranges. It is also found that, with these
constraints, UV photons injected by PBH evaporations are unlikely ionize vast
hydrogen atoms after recombination.


title:
The impact of encounters on the members of Local Group Analogs. A view
  from GALEX

abstract:
  The bright galaxy population of the Local Group Analog (LGA) LGG 225 has been
imaged with the Galaxy Evolution Explorer (GALEX) through its Far- and Near-UV
wavebands. A significant fraction of the group members appear to underwent
recent/on-going interaction episodes that strongly disturbed overall galaxy
morphology. UV-bright regions, sites of intense star formation activity
accompanied by intense dust extinction, mark the galaxy outskirts forming
irregular structures and tails. Compared to the Local Group, LGG 225 seems thus
to be experiencing a more intense and active evolutionary phase.


title:
The heavy traffic limit of an unbalanced generalized processor sharing
  model

abstract:
  This work considers a server that processes $J$ classes using the generalized
processor sharing discipline with base weight vector $\alpha=(\alpha
_1,...,\alpha_J)$ and redistribution weight vector
$\beta=(\beta_1,...,\beta_J)$. The invariant manifold $\mathcal{M}$ of the
so-called fluid limit associated with this model is shown to have the form
$\mathcal{M}=\{x\in\mathbb{R}_+^J:x_j=0 for j\in\mathcal{S}\}$, where
$\mathcal{S}$ is the set of strictly subcritical classes, which is identified
explicitly in terms of the vectors $\alpha$ and $\beta$ and the long-run
average work arrival rates $\gamma_j$ of each class $j$. In addition, under
general assumptions, it is shown that when the heavy traffic condition
$\sum_{j=1}^J\gamma_j=\sum_{j=1}^J\alpha_j$ holds, the functional central limit
of the scaled unfinished work process is a reflected diffusion process that
lies in $\mathcal{M}$. The reflected diffusion limit is characterized by the
so-called extended Skorokhod map and may fail to be a semimartingale. This
generalizes earlier results obtained for the simpler, balanced case where
$\gamma_j=\alpha_j$ for $j=1,...,J$, in which case $\mathcal{M}=\mathbb{R}_+^J$
and there is no state-space collapse. Standard techniques for obtaining
diffusion approximations cannot be applied in the unbalanced case due to the
particular structure of the GPS model. Along the way, this work also
establishes a comparison principle for solutions to the extended Skorokhod map
associated with this model, which may be of independent interest.


title: Multiple Stellar Populations in Galactic GCs: Observational Evidence

abstract:
  An increasing number of photometric observations of multiple stellar
populations in Galactic globular clusters is seriously challenging the paradigm
of GCs hosting single, simple stellar populations. These multiple populations
manifest themselves in a split of some evolutionary sequences of the cluster
color-magnitude diagrams. In this paper we will summarize the observational
scenario.


title: Explicit calculations of automorphic forms for definite unitary groups

abstract:
  I give an algorithm for computing the full space of automorphic forms for
definite unitary groups over Q, and apply this to calculate the automorphic
forms of level $G(Z-hat)$ and various small weights for an example of a rank 3
unitary group. This leads to some examples of various types of endoscopic
lifting from automorphic forms for U_1 x U_1 x U_1 and U_1 x U_2, and to an
example of a non-endoscopic form of weight (3,3) corresponding to a family of
3-dimensional irreducible l-adic Galois representations. I also compute the
2-adic slopes of some automorphic forms with level structure at 2, giving
evidence for the local constancy of the slopes.


title: Photometric binaries in fifty Globular Clusters

abstract:
  The HST/ACS Survey of Galactic globular clusters (GGCs) is a HST Treasury
project aimed at obtaining high precision photometry in a large sample of
globular clusters. The homogeneous photometric catalogs that has been obtained
from these data by Anderson et al. (2008) represents a golden mine for a lot of
astrophysical studies.
  In this paper we used the catalog to analyse the properties of MS-MS binary
systems from a sample of fifty GGCs. We measured the fraction of binaries
(divided in different groups), studied their radial distribution and
constrained the mass ratio distribution. We investigated possible relations
between the fraction of binaries and the main parameters of their host GGCs.
  We found a significant anti-correlation between the binary fraction in a
cluster and its absolute luminosity (mass).


title: Conjugacy classes in parabolic subgroups of general linear groups

abstract:
  We prove a formula connecting the number of unipotent conjugacy classes in a
maximal parabolic subgroup of a finite general linear group with the numbers of
unipotent conjugacy classes in various parabolic subgroups in smaller
dimensions. We generalise this formula and deduce a number of corollaries; in
particular, we express the number of conjugacy classes of unitriangular
matrices over a finite field in terms of the numbers of unipotent conjugacy
classes in maximal parabolic subgroups over the same field. We show how the
numbers of unipotent conjugacy classes in parabolic subgroups of small
dimensions may be calculated.


title: On integrability of the vector short pulse equation

abstract:
  Using the Painleve analysis preceded by appropriate transformations of
nonlinear systems under investigation, we discover two new cases in which the
Pietrzyk-Kanattsikov-Bandelow vector short pulse equation must be integrable
due to the results of the Painleve test. Those cases are technologically
important because they correspond to the propagation of polarized ultra-short
light pulses in usual isotropic silica optical fibers.

categories: nlin.SI math-ph math.AP math.MP physics.optics


title: Viscous fluid dynamics in Au+Au collisions at RHIC

abstract:
  We have studied the space-time evolution of minimally viscous
($\frac{\eta}{s}$=0.08) QGP fluid, undergoing boost-invariant longitudinal
motion and arbitrary transverse expansion. Relaxation equations for the shear
stress tensor components, derived from the phenomenological Israel-Stewart's
theory of dissipative relativistic fluid, are solved simultaneously with the
energy-momentum conservation equations. Comparison of evolution of ideal and
viscous fluid, both initialized under the similar conditions, e.g. same
equilibration time, energy density and velocity profile, indicate that in
viscous fluid, energy density or temperature of the fluid evolve slowly than in
an ideal fluid. Transverse expansion is also more in viscous evolution. We have
also studied particle production in viscous dynamics. Compared to ideal
dynamics, in viscous dynamics, particle yield at high $p_T$ is increased.
Elliptic flow on the other hand decreases. Minimally viscous QGP fluid,
initialized at entropy density $s_{ini}$=110 $fm^{-3}$ at the initial time
$\tau_i$=0.6 fm, if freeze-out at temperature $T_F$=130 MeV, explains the
centrality dependence of $p_T$ spectra of identified particles. Experimental
$p_T$ spectra of $\pi^-$, $K^+$ and protons in 0-5%, 5-10%, 10-20%, 20-30%,
30-40% and 40-50% Au+Au collisions are well reproduced through out the
experimental $p_T$ range. This is in contrast to ideal dynamics, where, the
spectra are reproduced only up to $p_T\approx$1.5 GeV. Minimally viscous QGP
fluid, also explain the elliptic flow in mid-central (10-20%, 16-23%, 20-30%)
collisions. The minimum bias elliptic flow is also explained. However, the
model under-predict/over-predict the elliptic flow in very central/peripheral
collisions.


title: SPM Bulletin 23

abstract:
  A surprising number of new results in "core" SPM in the last quarter of 2007,
and some other beautiful fundamental results are announced.


title:
Formation of Stellar Clusters and the Importance of Thermodynamics for
  Fragmentation

abstract:
  We discuss results from numerical simulations of star cluster formation in
the turbulent interstellar medium (ISM). The thermodynamic behavior of the
star-forming gas plays a crucial role in fragmentation and determines the
stellar mass function as well as the dynamic properties of the nascent stellar
cluster. This holds for star formation in molecular clouds in the solar
neighborhood as well as for the formation of the very first stars in the early
universe. The thermodynamic state of the ISM is a result of the balance between
heating and cooling processes, which in turn are determined by atomic and
molecular physics and by chemical abundances. Features in the effective
equation of state of the gas, such as a transition from a cooling to a heating
regime, define a characteristic mass scale for fragmentation and so set the
peak of the initial mass function of stars (IMF). As it is based on fundamental
physical quantities and constants, this is an attractive approach to explain
the apparent universality of the IMF in the solar neighborhood as well as the
transition from purely primordial high-mass star formation to the more normal
low-mass mode observed today.


title: Curvature Distribution of Worm-like Chains in Two and Three Dimensions

abstract:
  Bending of worm-like polymers carries an energy penalty which results in the
appearance of a persistence length l such that the polymer is straight on
length scales smaller than l and bends only on length scales larger than this
length. Intuitively, this leads us to expect that the most probable value of
the local curvature of a worm-like polymer undergoing thermal fluctuations in a
solvent, is zero. We use simple geometric arguments and Monte Carlo simulations
to show that while this expectation is indeed true for polymers on surfaces (in
two dimensions), in three dimensions the probability of observing zero
curvature anywhere along the worm-like chain, vanishes.


title: The expected duration of random sequential adsorption

abstract:
  When gas molecules bind to a surface they may do so in such a way that the
adsorption of one molecule inhibits the arrival of others. We consider random
sequential adsorption in which the empty sites of a graph are irreversibly
occupied in random order by a variety of types of ``particles.'' In a finite
region the process terminates when no more particles can arrive. A universal
asymptotic formula for the mean duration is given.


title:
Synchronizing continuous-time neutrally stable linear systems via
  partial-state coupling

abstract:
  Synchronization of coupled continuous-time linear systems is studied in a
general setting. For identical neutrally-stable linear systems that are
detectable from their outputs, it is shown that a linear output feedback law
exists under which the coupled systems globally asymptotically synchronize
under all fixed (directed) connected network topologies. An algorithm is
provided to compute one such feedback law based on individual system
parameters. The dual case, where individual systems are neutrally stable and
stabilizable from their inputs, is also considered and parallel results are
established.


title: How was the mushroom-shaped GW 123.4--1.5 formed in the Galactic disk?

abstract:
  The unusual mushroom-shaped HI cloud, GW 123.4--1.5, is hundreds of parsecs
in size but does not show any correlations to HI shells or chimney structures.
To investigate the origin and velocity structure of GW 123.4--1.5, we perform
three-dimensional hydrodynamical simulations of the collision of a
high-velocity cloud with the Galactic disk. We also perform a parameter study
of the density, radius, and incident angle of the impact cloud. The numerical
experiments indicate that we reproduce the mushroom-shaped structure which
resembles GW 123.4--1.5 in shape, size, position-velocity across the cap of the
mushroom, and the density ratio between the mushroom and surrounding gas. GW
123.4--1.5 is expected to be formed by the almost head-on collision of a HVC
with velocity $\sim 100 \kms$ and mass $\sim 10^5 \Msun$ about $5 \times 10^7
\yr$ ago. A mushroom-shaped structure like GW 123.4--1.5 must be infrequent on
the Galactic plane, because the head-on collision which explains the mushroom
structure seems rare for observed HVCs. HVC-disk collision explains not only
the origin of the mushroom-shaped structure but also the formation of a variety
of structures like shells, loops, and vertical structures in our Galaxy.


title:
Helmet Streamers with Triple Structures: Simulations of resistive
  dynamics

abstract:
  Recent observations of the solar corona with the LASCO coronagraph on board
of the SOHO spacecraft have revealed the occurrence of triple helmet streamers
even during solar minimum, which occasionally go unstable and give rise to
large coronal mass ejections. There are also indications that the slow solar
wind is either a combination of a quasi-stationary flow and a highly
fluctuating component or may even be caused completely by many small eruptions
or instabilities. As a first step we recently presented an analytical method to
calculate simple two-dimensional stationary models of triple helmet streamer
configurations. In the present contribution we use the equations of time-
dependent resistive magnetohydrodynamics to investigate the stability and the
dynamical behaviour of these configurations. We particularly focus on the
possible differences between the dynamics of single isolated streamers and
triple streamers and on the way in which magnetic reconnection initiates both
small scale and large scale dynamical behaviour of the streamers. Our results
indicate that small eruptions at the helmet streamer cusp may incessantly
accelerate small amounts of plasma without significant changes of the
equilibrium configuration and might thus contribute to the non-stationary slow
solar wind. On larger time and length scales, large coronal eruptions can occur
as a consequence of large scale magnetic reconnection events inside the
streamer configuration. Our results also show that triple streamers are usually
more stable than a single streamer.


title: Lower Dimensional Branes in Boundary Conformal Field Theory

abstract:
  In the presence of constant background electromagnetic fields, we discuss
three types of exactly marginal boundary tachyon operators for static kinks in
boundary conformal field theory. Functional forms of three operators are
hyperbolic sine, hyperbolic cosine, and exponential types, and they describe
codimension-one solitons when the transverse electric field has overcritical
value. The energy-momentum tensor and the source for antisymmetric tensor field
are computed in the path integral approach for the exponential-type tachyon
vertex operator.


title:
A classical interpretation of quantum mechanics and the measurement
  problem

abstract:
  In this paper a didactic approach is described which immediately leads to an
understanding of those postulates of quantum mechanics used most frequently in
quantum computation. Moreover, an interpretation of quantum mechanics is
presented which is motivated by retaining the point of view of classical
mechanics as much as possible, and which is consistent with relativity theory.
Everything can be written down in terms of well-known mathematical formulations
that can be found in every textbook about quantum mechanics. Therefore, in this
version, almost no formulas are used.


title:
Cluster sum rules for three-body systems with angular-momentum dependent
  interactions

abstract:
  We derive general expressions for non-energy weighted and energy-weighted
cluster sum rules for systems of three charged particles. The interferences
between pairs of particles are found to play a substantial role. The
energy-weighted sum rule is usually determined by the kinetic energy operator,
but we demonstrate that it has similar additional contributions from the
angular momentum and parity dependence of two- and three-body potentials
frequently used in three-body calculations. The importance of the different
contributions is illustrated with the dipole excitations in $^6$He. The results
are compared with the available experimental data.


title:
Intensity process and compensator: A new filtration expansion approach
  and the Jeulin--Yor theorem

abstract:
  Let $(X_t)_{t\ge0}$ be a continuous-time, time-homogeneous strong Markov
process with possible jumps and let $\tau$ be its first hitting time of a Borel
subset of the state space. Suppose $X$ is sampled at random times and suppose
also that $X$ has not hit the Borel set by time $t$. What is the intensity
process of $\tau$ based on this information? This question from credit risk
encompasses basic mathematical problems concerning the existence of an
intensity process and filtration expansions, as well as some conceptual issues
for credit risk. By revisiting and extending the famous Jeulin--Yor [Lecture
Notes in Math. 649 (1978) 78--97] result regarding compensators under a general
filtration expansion framework, a novel computation methodology for the
intensity process of a stopping time is proposed. En route, an analogous
characterization result for martingales of Jacod and Skorohod [Lecture Notes in
Math. 1583 (1994) 21--35] under local jumping filtration is derived.


title: Soft X-ray to Far Infrared luminosities ratio in star-forming galaxies

abstract:
  A good correlation has been found in star-forming galaxies between the soft
X-ray and the far infrared or radio luminosities. In this work we analyze the
relation between the soft X-ray and far infrared luminosities as predicted by
evolutionary population synthesis models, aiming first to test the validity of
the soft X-ray luminosity as a star formation rate estimator, using the already
known calibration of the FIR luminosity as a proxy, and second proposing a
calibration based on the predictions of evolutionary synthesis models. We have
computed the soft X-ray and far infrared luminosities expected for a massive
starburst as a function of evolutionary state, efficiency of the conversion of
mechanical energy into soft X-ray luminosity, star formation regime
(instantaneous or extended) and dust abundance, and have compared the
predictions with observational values for a sample of 62 star-forming galaxies
taken from the literature. The observational Lsoftx/Lfir ratios are consistent
with the predictions by the models under realistic assumptions (young
starbursts, efficiency in the re-processing of mechanical energy of few
percent), confirming the direct relation of the diffuse soft X-ray emission
with the star formation episode. The soft X-ray emission of the diffuse,
extended gas surrounding massive star forming regions can be used as a Star
Formation Rate estimator. The empirical calibrations presented in the
literature are supported by the predictions of evolutionary synthesis models
and by the analysis of a larger sample of star-forming galaxies, but it is
biased towards galaxies dominated by relatively unevolved starbursts.


title: Production of Slow Protonium in Vacuum

abstract:
  We describe how protonium, the quasi-stable antiproton-proton bound system,
has been synthesized following the interaction of antiprotons with the
molecular ion H$_2^+$ in a nested Penning trap environment. From a careful
analysis of the spatial distributions of antiproton annihilation events in the
ATHENA experiment, evidence is presented for protonium production with sub-eV
kinetic energies in states around $n$ = 70, with low angular momenta. This work
provides a new 2-body system for study using laser spectroscopic techniques.


title: The Fedosov *-product in Mathematica

abstract:
  The computer program `Fecom.nb' implementing the Fedosov *-product in Darboux
coordinates is presented. It has been written in Mathematica 6.0 but it can be
easily modified to be run in some earlier version of Mathematica. To optimize
computations elements of the Weyl algebra are treated as polynomials. Several
procedures which order the terms are included.
  The program is available at the web page
http://cpc.cs.qub.ac.uk/summaries/AEBU_v1_0.html


title:
Fragmentation cross sections of Fe^{26+}, Si^{14+} and C^{6+} ions of
  0.3-10 A GeV on polyethylene, CR39 and aluminum targets

abstract:
  We present new measurements of the total and partial fragmentation cross
sections in the energy range 0.3-10 A GeV of 56Fe, 28Si and 12C beams on
polyethylene, CR39 and aluminum targets. The exposures were made at BNL, USA
and HIMAC, Japan. The CR39 nuclear track detectors were used to identify the
incident and survived beams and their fragments. The total fragmentation cross
sections for all targets are almost energy independent while they depend on the
target mass. The measured partial fragmentation cross sections are also
discussed.


title: Chaos in a generalized Lorenz system

abstract:
  A three-component dynamic system with influence of pumping and nonlinear
dissipation describing a quantum cavity electrodynamic device is studied.
Different dynamical regimes are investigated in terms of divergent trajectories
approaches and fractal statistics. It has been shown, that in such a system
stable and unstable dissipative structures type of limit cycles can be formed
with variation of pumping and nonlinear dissipation rate. Transitions to
chaotic regime and the corresponding chaotic attractor are studied in details.


title:
Two-band parallel conductivity at terahertz frequencies in the
  superconducting state of MgB$_2$.

abstract:
  The optical response of the two-band superconductor MgB$_2$ has been studied
in the 0.7-4 THz range on films with very low impurity level. The effect of the
high-energy $\sigma$-gap is observed in the ratio $R_S/R_N$ between the normal
and superconducting state reflectance, while in a neutron irradiated film with
a slightly higher impurity level mainly the effect of the $\pi$-gap is evident
as reported in previous experiments. At terahertz frequencies, the
electrodynamic of MgB$_2$ can be well described by the two-band parallel
conductivity model and is dominated by the $\pi$-bands when the impurity level
is only slightly higher than that of an ultra-clean sample.


title:
Formation of hard VHE gamma-ray spectra of blazars due to internal
  photon-photon absorption

abstract:
  The energy spectra of TeV gamma-rays from blazars, after being corrected for
intergalatic absorption in the Extragalactic Background Light (EBL), appear
unusually hard, a fact that poses challenges to the conventional models of
particle acceleration in TeV blazars and/or to the EBL models. In this paper we
show that the internal absorption of gamma-rays caused by interactions with
dense narrow-band radiation fields in the vicinity of compact gamma-ray
production regions can lead to the formation of gamma-ray spectra of an almost
arbitrary hardness. This allows significant relaxation of the current tight
constraints on particle acceleration and radiation models, although at the
expense of enhanced requirements to the available nonthermal energy budget. The
latter, however, is not a critical issue, as long as it can be largely
compensated by the Doppler boosting, assuming very large ($\geq 30$) Doppler
factors of the relativistically moving gamma-ray production regions. The
suggested scenario of formation of hard gamma-ray spectra predicts detectable
synchrotron radiation of secondary electron-positron pairs which might require
a revision of the current ``standard paradigm'' of spectral energy
distributions of gamma-ray blazars. If the primary gamma-rays are of hadronic
origin related to $pp$ or $p \gamma$ interactions, the ``internal gamma-ray
absorption'' model predicts neutrino fluxes close to the detection threshold of
the next generation high energy neutrino detectors.


title: Descent methods for Nonnegative Matrix Factorization

abstract:
  In this paper, we present several descent methods that can be applied to
nonnegative matrix factorization and we analyze a recently developped fast
block coordinate method called Rank-one Residue Iteration (RRI). We also give a
comparison of these different methods and show that the new block coordinate
method has better properties in terms of approximation error and complexity. By
interpreting this method as a rank-one approximation of the residue matrix, we
prove that it \emph{converges} and also extend it to the nonnegative tensor
factorization and introduce some variants of the method by imposing some
additional controllable constraints such as: sparsity, discreteness and
smoothness.


title: Einstein-Podolsky-Rosen correlations of vector bosons

abstract:
  We calculate the joint probabilities and the correlation function in
Einstein--Podolsky--Rosen type experiments with a massive vector boson in the
framework of quantum field theory. We report on the strange behavior of the
correlation function (and the probabilities) -- the correlation function, which
in the relativistic case still depends on the particle momenta, for some fixed
configurations has local extrema. We also show that relativistic spin-1
particles violate some Bell inequalities more than nonrelativistic ones and
that the degree of violation of the Bell inequality is momentum dependent.


title: Quantum gates and quantum algorithms with Clifford algebra technique

abstract:
  We use our Clifford algebra technique, that is nilpotents and projectors
which are binomials of the Clifford algebra objects $\gamma^a$ with the
property $\{\gamma^a,\gamma^b\}_+ = 2 \eta^{ab}$, for representing quantum
gates and quantum algorithms needed in quantum computers in an elegant way. We
identify $n$-qubits with spinor representations of the group SO(1,3) for a
system of $n$ spinors. Representations are expressed in terms of products of
projectors and nilpotents. An algorithm for extracting a particular information
out of a general superposition of $2^n$ qubit states is presented. It
reproduces for a particular choice of the initial state the Grover's algorithm.


title: New Routes to Solitons in Quasi One-Dimensional Conductors

abstract:
  We collect evidences on existence of microscopic solitons, and their
determining role in electronic processes of quasi-1D conductors. The
ferroelectric charge ordering gives access to several types of solitons in
conductivity and permittivity, and to solitons' bound pairs in optics - both in
insulating and conducting cases of TMTTF and TMTSF subfamilies. The excursion
to physics of conjugated polymers allows to suggest further experiments.
Internal tunnelling in Charge Density Waves goes through the channel of
"amplitude solitons", which correspond to the long sought quasi-particle - the
spinon. The same experiment gives an access to the reversible reconstruction of
the junction via spontaneous creation of a lattice of 2Pi solitons - a grid of
dislocations. The individual 2Pi solitons have been visually captured in recent
STM experiments. Junctions of organic and oxide conductors are anticipated to
show similar effects of reconstruction.


title: Time discretization and Markovian iteration for coupled FBSDEs

abstract:
  In this paper we lay the foundation for a numerical algorithm to simulate
high-dimensional coupled FBSDEs under weak coupling or monotonicity conditions.
In particular, we prove convergence of a time discretization and a Markovian
iteration. The iteration differs from standard Picard iterations for FBSDEs in
that the dimension of the underlying Markovian process does not increase with
the number of iterations. This feature seems to be indispensable for an
efficient iterative scheme from a numerical point of view. We finally suggest a
fully explicit numerical algorithm and present some numerical examples with up
to 10-dimensional state space.


title:
Perturbation theory for large Stokes number particles in random velocity
  fields

abstract:
  We derive a perturbative approach to study, in the large inertia limit, the
dynamics of solid particles in a smooth, incompressible and finite-time
correlated random velocity field. We carry on an expansion in powers of the
inverse square root of the Stokes number, defined as the ratio of the
relaxation time for the particle velocities and the correlation time of the
velocity field. We describe in this limit the residual concentration
fluctuations of the particle suspension, and determine the contribution to the
collision statistics produced by clustering. For both concentration
fluctuations and collision velocities, we analyze the differences with the
compressible one-dimensional case.


title: Thermal desorption of CH4 retained in CO2 ice

abstract:
  CO2 ices are known to exist in different astrophysical environments. In spite
of this, its physical properties (structure, density, refractive index) have
not been as widely studied as those of water ice. It would be of great value to
study the adsorption properties of this ice in conditions related to
astrophysical environments. In this paper, we explore the possibility that CO2
traps relevant molecules in astrophysical environments at temperatures higher
than expected from their characteristic sublimation point. To fulfil this aim
we have carried out desorption experiments under High Vacuum conditions based
on a Quartz Crystal Microbalance and additionally monitored with a Quadrupole
Mass Spectrometer. From our results, the presence of CH4 in the solid phase
above the sublimation temperature in some astrophysical scenarios could be
explained by the presence of several retaining mechanisms related to the
structure of CO2 ice.


title: Operator Approach to Boundary Liouville Theory

abstract:
  We propose new methods for calculation of the discrete spectrum, the
reflection amplitude and the correlation functions of boundary Liouville theory
on a strip with Lorentzian signature. They are based on the structure of the
vertex operator $V=e^{-\phi}$ in terms of the asymptotic operators. The methods
first are tested for the particle dynamics in the Morse potential, where
similar structures appear. Application of our methods to boundary Liouville
theory reproduces the known results obtained earlier in the bootstrap approach,
but there can arise a certain extension when the boundary parameters are near
to critical values. Namely, in this case we have found up to four different
equidistant series of discrete spectra, and the reflection amplitude is
modified respectively.


title:
Fine-structure splitting reduction of ionized impurity bound exciton in
  quantum dot

abstract:
  The ground-state energy and fine-structure splitting of ionized shallow donor
impurity-exciton complex in quantum dots are investigated. It is found that
fine-structure splitting could be largely reduced by the off-center ionized
impurities since the anisotropic shape of exciton envelope function is
significantly changed. Anomalous Stark shifts of the ground-state energy and
efficient tuning of the fine-structure splitting by the external electric field
due to the local electric field produced by the ionized impurities are
discussed. The scheme may be useful for the design of the quantum dots-based
entangled-photon source.


title:
Naturalness of exponential cosmon potentials and the cosmological
  constant problem

abstract:
  We discuss the naturalness of exponential potentials for quintessence,
showing that the resulting almost flat direction in the space of scalar fields,
as well as the small time dependent cosmon mass, can be related to an anomalous
dilatation symmetry. We argue that the physics of the cosmological constant is
Planck scale physics, and comment on the role of quantum fluctuations. We
present three higher dimensional scenarios how a runaway of the ``cosmological
constant'' to zero can be combined with stable particle physics properties,
leading at most to small variations of the ``fundamental couplings''.


title:
A Pyramidal Evolutionary Algorithm with Different Inter-Agent Partnering
  Strategies for Scheduling Problems

abstract:
  This paper combines the idea of a hierarchical distributed genetic algorithm
with different inter-agent partnering strategies. Cascading clusters of
sub-populations are built from bottom up, with higher-level sub-populations
optimising larger parts of the problem. Hence higher-level sub-populations
search a larger search space with a lower resolution whilst lower-level
sub-populations search a smaller search space with a higher resolution. The
effects of different partner selection schemes amongst the agents on solution
quality are examined for two multiple-choice optimisation problems. It is shown
that partnering strategies that exploit problem-specific knowledge are superior
and can counter inappropriate (sub-) fitness measurements.


title: Poincar\'e Invariant Three-Body Scattering at Intermediate Energies

abstract:
  The relativistic Faddeev equation for three-nucleon scattering is formulated
in momentum space and directly solved in terms of momentum vectors without
employing a partial wave decomposition. The equation is solved through Pad\'e
summation, and the numerical feasibility and stability of the solution is
demonstrated. Relativistic invariance is achieved by constructing a dynamical
unitary representation of the Poincar\'e group on the three-nucleon Hilbert
space. Based on a Malfliet-Tjon type interaction, observables for elastic and
break-up scattering are calculated for projectile energies in the intermediate
energy range up to 2 GeV, and compared to their nonrelativistic counterparts.
The convergence of the multiple scattering series is investigated as a function
of the projectile energy in different scattering observables and
configurations. Approximations to the two-body interaction embedded in the
three-particle space are compared to the exact treatment.


title:
Curvature invariants, Killing vector fields, connections and
  cohomogeneity

abstract:
  A direct, bundle-theoretic method for defining and extending local isometries
out of curvature data is developed. As a by-product, conceptual direct proofs
of a classical result of Singer and a recent result of the authors are derived.


title:
An O(N^2) Approximation for Hydrodynamic Interactions in Brownian
  Dynamics Simulations

abstract:
  In the Ermak-McCammon algorithm for Brownian Dynamics, the hydrodynamic
interactions (HI) between N spherical particles are described by a 3N x 3N
diffusion tensor. This tensor has to be factorized at each timestep with a
runtime of O(N^3), making the calculation of the correlated random
displacements the bottleneck for many-particle simulations. Here we present a
faster algorithm for this step, which is based on a truncated expansion of the
hydrodynamic multi-particle correlations as two-body contributions. The
comparison to the exact algorithm and to the Chebyshev approximation of Fixman
verifies that for bead-spring polymers this approximation yields about 95% of
the hydrodynamic correlations at an improved runtime scaling of O(N^2) and a
reduced memory footprint. The approximation is independent of the actual form
of the hydrodynamic tensor and can be applied to arbitrary particle
configurations. This now allows to include HI into large many-particle Brownian
dynamics simulations, where until now the runtime scaling of the correlated
random motion was prohibitive.


title:
Optical properties of coupled metal-semiconductor and metal-molecule
  nanocrystal complexes: the role of multipole effects

abstract:
  We investigate theoretically the effects of interaction between an optical
dipole (semiconductor quantum dot or molecule) and metal nanoparticles. The
calculated absorption spectra of hybrid structures demonstrate strong effects
of interference coming from the exciton-plasmon coupling. In particular, the
absorption spectra acquire characteristic asymmetric lineshapes and strong
anti-resonances. We present here an exact solution of the problem beyond the
dipole approximation and find that the multipole treatment of the interaction
is crucial for the understanding of strongly-interacting exciton-plasmon
nano-systems. Interestingly, the visibility of the exciton resonance becomes
greatly enhanced for small inter-particle distances due to the interference
phenomenon, multipole effects, and electromagnetic enhancement. We find that
the destructive interference is particularly strong. Using our exact theory, we
show that the interference effects can be observed experimentally even in the
exciting systems at room temperature.


title:
The search for complex molecules in the ISM: a complete 3 mm line survey
  of Sgr B2-N and -M

abstract:
  Famous for the extraordinary richness of its molecular content, the Sgr B2
molecular cloud complex is the prime target in the long-standing search for
ever more complex species. We have completed a molecular line survey of the hot
dense cores Sgr B2(N) and Sgr B2(M) in the 3 mm wavelength range with the IRAM
30 m telescope. We performed the analysis of this huge data set by modeling the
whole spectrum at once in the LTE approximation. Ongoing analyses yield an
average line density of about 100 features/GHz above 3 sigma for Sgr B2(N),
emitted and/or absorbed by a total of 51 molecular species. We find lines from
60 rare isotopologues and from 41 vibrationally excited states in addition to
the main species, vibrational ground state lines. For Sgr B2(M), we find about
25 features/GHz above 3 sigma, from 41 molecular species plus 50 isotopologues
and 20 vibrationally excited states. Thanks to the constant updates to the
Cologne Database for Molecular Spectroscopy, we are working our way through the
assignment of the unidentified features, currently 40% and 50% above 3 sigma
for Sgr B2(N) and Sgr B2(M), respectively.


title: Computing nonlinear force free coronal magnetic fields

abstract:
  Knowledge of the structure of the coronal magnetic field is important for our
understanding of many solar activity phenomena, e.g. flares and CMEs. However,
the direct measurement of coronal magnetic fields is not possible with present
methods, and therefore the coronal field has to be extrapolated from
photospheric measurements. Due to the low plasma beta the coronal magnetic
field can usually be assumed to be approximately force free, with electric
currents flowing along the magnetic field lines. There are both observational
and theoretical reasons which suggest that at least prior to an eruption the
coronal magnetic field is in a nonlinear force free state. Unfortunately the
computation of nonlinear force free fields is way more difficult than potential
or linear force free fields and analytic solutions are not generally available.
We discuss several methods which have been proposed to compute nonlinear force
free fields and focus particularly on an optimization method which has been
suggested recently. We compare the numerical performance of a newly developed
numerical code based on the optimization method with the performance of another
code based on an MHD relaxation method if both codes are applied to the
reconstruction of a semi-analytic nonlinear force-free solution. The
optimization method has also been tested for cases where we add random noise to
the perfect boundary conditions of the analytic solution, in this way mimicking
the more realistic case where the boundary conditions are given by vector
magnetogram data. We find that the convergence properties of the optimization
method are affected by adding noise to the boundary data and we discuss
possibilities to overcome this difficulty.


title: Exploring Urban Environments By Random Walks

abstract:
  A complex web of roads, walkways and public transport systems can hide areas
of geographical isolation very difficult to analyze. Random walks are used to
spot the structural details of urban fabric.


title: Uniaxially anisotropic antiferromagnets in a field on a square lattice

abstract:
  Classical uniaxially anisotropic Heisenberg and XY antiferromagnets in a
field along the easy axis on a square lattice are analysed, applying ground
state considerations and Monte Carlo techniques. The models are known to
display antiferromagnetic and spin-flop phases. In the Heisenberg case, a
single-ion anisotropy is added to the XXZ antiferromagnet, enhancing or
competing with the uniaxial exchange anisotropy. Its effect on the stability of
non-collinear structures of biconical type is studied. In the case of the
anisotropic XY antiferromagnet, the transition region between the
antiferromagnetic and spin-flop phases is found to be dominated by degenerate
bidirectional fluctuations. The phase diagram is observed to resemble closely
that of the XXZ antiferromagnet without single-ion anisotropy.


title: A Note on Affinely Regular Polygons

abstract:
  The affinely regular polygons in certain planar sets are characterized. It is
also shown that the obtained results apply to cyclotomic model sets and,
additionally, have consequences in the discrete tomography of these sets.


title: Detection of amino acetonitrile in Sgr B2(N)

abstract:
  Amino acids are building blocks of proteins and therefore key ingredients for
the origin of life. The simplest amino acid, glycine, has long been searched
for in the interstellar medium but has not been unambiguously detected so far.
Since the search for glycine has turned out to be extremely difficult, we aimed
at detecting a chemically related species (possibly a direct precursor), amino
acetonitrile. With the IRAM 30m telescope we carried out a complete line survey
of the hot core regions Sgr B2(N) and (M) in the 3 mm range, plus partial
surveys at 2 and 1.3 mm. We analyzed our 30m line survey in the LTE
approximation and modeled the emission of all known molecules simultaneously.
We identified spectral features at the frequencies predicted for amino
acetonitrile lines having intensities compatible with a unique rotation
temperature. We also used the VLA to look for cold, extended emission from
amino acetonitrile. We detected amino acetonitrile in Sgr B2(N) in our 30m
telescope line survey and conducted confirmatory observations of selected lines
with the IRAM PdB and the ATCA interferometers. The emission arises from a
known hot core, the Large Molecule Heimat, and is compact with a source
diameter of 2 arcsec (0.08 pc). We derived a column density of 2.8e16 cm-2, a
temperature of 100 K, and a linewidth of 7 km s-1. Based on the simultaneously
observed continuum emission, we calculated a density of 1.7e8 cm-3, a mass of
2340 Msun, and an amino acetonitrile fractional abundance of 2.2e-9. The high
abundance and temperature may indicate that amino acetonitrile is formed by
grain surface chemistry. We did not detect any hot, compact amino acetonitrile
emission toward Sgr B2(M) or any cold, extended emission toward Sgr B2, with
column-density upper limits of 6e15 and 3e12-14 cm-2, respectively. (abridged)


title: A Global Approach to the Theory of Connections in Finsler Geometry

abstract:
  Adopting the pullback approach to global Finsler geometry, the aim of the
present paper is to provide intrinsic (coordinate-free) proofs of the existence
and uniqueness theorems for the Chern (Rund) and Hashiguchi connections on a
Finsler manifold. To accomplish this, we introduce and investigate the notions
of semispray and nonlinear connection associated with a given regular
connection, in the pullback bundle. Moreover, it is shown that for the the
Chern (Rund) and Hashiguchi connections, the associated semispray coincides
with the canonical spray and the associated nonlinear connection coincides with
the Barthel connection. Explicit intrinsic expressions relating these
connections and the Cartan connection are deduced. Although our investigation
is entirely global, the local expressions of the obtained results, when
calculated, coincide with the existing classical local results. We provide, for
the sake of completeness and for comparison reasons, two appendices, one of
them presenting a global survey of canonical linear connections in Finsler
geometry and the other presenting a local survey of our global approach.


title: Running-mode resonance in A.C.-biased periodic potential

abstract:
  We investigate the stochastic dynamics of a particle in the presence of a
modulated sinusoidal potential. Using the time derivative of the winding
number, we quantify the particle's motion according to its running time, the
time it runs monotonically to the left or right. For a range of model
parameters, we show that, in the overdamped regime, the particle's motion in
this modulated washboard potential exhibits stochastic resonance. We briefly
suggest possible applications of our results, including the amplification of
signals for measurement devices and in stimulated tunneling of Bose-Einstein
condensates.


title: Dispersion Relation Bounds for pi pi Scattering

abstract:
  Axiomatic principles such as analyticity, unitarity and crossing symmetry
constrain the second derivative of the pi pi scattering amplitudes in some
channels to be positive in a region of the Mandelstam plane. Since this region
lies in the domain of validity of chiral perturbation theory, we can use these
positivity conditions to bound linear combinations of \bar{l}_1 and \bar{l}_2.
We compare our predictions with those derived previously in the literature
using similar methods. We compute the one-loop pi pi scattering amplitude in
the linear sigma model (LSM) using the MS-bar scheme, a result hitherto absent
in the literature. The LSM values for \bar{l}_1 and \bar{l}_2 violate the
bounds for small values of m_sigma/m_pi. We show how this can occur, while
still being consistent with the axiomatic principles.


title: Casimir repulsion and metamaterials

abstract:
  We analyze the conditions for getting the Casimir repulsion between two
nonequal plates. The force between plates with magnetic permeability defined by
Drude or Lorentz models is calculated. The short and long distance limits of
the force are derived. The Casimir set-up with the hypothetical perfect
matching metamaterial is discussed. We put into question the possibility of
getting repulsion within the design of metamaterials based on metallic
inclusions.


title:
Invariant Measures and Maximal L^2 Regularity for Nonautonomous
  Ornstein-Uhlenbeck Equations

abstract:
  We characterize the domain of the realization of the linear parabolic
operator Gu := u_t + L(t)u (where, for each real t, L(t) is an
Ornstein-Uhlenbeck operator), in L^2 spaces with respect to a suitable measure,
that is invariant for the associated evolution semigroup. As a byproduct, we
obtain optimal L^2 regularity results for evolution equations with
time-depending Ornstein-Uhlenbeck operators.


title:
Two-dimensional rational solitons and their blow-up via the Moutard
  transformation

abstract:
  By using the Moutard transformation of two-dimensional Schroedinger operators
we derive a procedure for constructing explicit examples of such operators with
rational fast decaying potentials and degenerate $L_2$-kernels (this
construction was sketched in arXiv:0706.3595) and show that if we take some of
these potentials as the Cauchy data for the Novikov-Veselov equation (a
two-dimensional version of the Korteweg-de Vries equation), then the
corresponding solutions blow up in a finite time


title: Extrasolar Planet Interactions

abstract:
  The dynamical interactions of planetary systems may be a clue to their
formation histories. Therefore, the distribution of these interactions provides
important constraints on models of planet formation. We focus on each system's
apsidal motion and proximity to dynamical instability. Although only ~25
multiple planet systems have been discovered to date, our analyses in these
terms have revealed several important features of planetary interactions. 1)
Many systems interact such that they are near the boundary between stability
and instability. 2) Planets tend to form such that at least one planet's
eccentricity periodically drops to near zero. 3) Mean-motion resonant pairs
would be unstable if not for the resonance. 4) Scattering of approximately
equal mass planets is unlikely to produce the observed distribution of apsidal
behavior. 5) Resonant interactions may be identified through calculating a
system's proximity to instability, regardless of knowledge of angles such as
mean longitude and longitude of periastron (e.g. GJ 317 b and c are probably in
a 4:1 resonance). These properties of planetary systems have been identified
through calculation of two parameters that describe the interaction. The
apsidal interaction can be quantified by determining how close a planet is to
an apsidal separatrix (a boundary between qualitatively different types of
apsidal oscillations, e.g. libration or circulation of the major axes). The
proximity to instability can be measured by comparing the observed orbital
elements to an analytic boundary that describes a type of stability known as
Hill stability. We have set up a website dedicated to presenting the most
up-to-date information on dynamical interactions:
http://www.lpl.arizona.edu/~rory/research/xsp/dynamics


title:
A New Perspective for an Existing Homology Theory of Links Embedded in
  I-Bundles

abstract:
  This paper introduces a homology theory for links in I-bundles over an
orientable surface. The theory is unique in that the elements of the chain
groups are surfaces instead of diagrams. It is then shown this theory yields
the same results as the homology theory constructed by Asaeda, Przytycki and
Sikora.


title: The Computational Power of Symmetric Hamiltonians

abstract:
  The presence of symmetries, be they discrete or continuous, in a physical
system typically leads to a reduction in the problem to be solved. Here we
report that neither translational invariance nor rotational invariance reduce
the computational complexity of simulating Hamiltonian dynamics; the problem is
still BQP complete, and is believed to be hard on a classical computer. This is
achieved by designing a system to implement a Universal Quantum Interface, a
device which enables control of an entire computation through the control of a
fixed number of spins, and using it as a building-block to entirely remove the
need for control, except in the system initialisation. Finally, it is shown
that cooling such Hamiltonians to their ground states in the presence of random
magnetic fields solves a QMA-complete problem.


title:
Static and dynamic properties of 0, pi, and 0-pi ferromagnetic tunnel
  Josephson Junctions

abstract:
  We present experimental studies of static and dynamic properties of 0, pi and
0-pi superconductor-insulator-ferromagnet-superconductor (SIFS) Josephson
junctions of small and intermediate length. In the underdamped limit these
junctions exhibit a rich dynamical behavior such as resonant steps on the
current-voltage characteristics. Varying the experimental conditions, zero
field steps, Fiske steps and Shapiro steps are observed with a high resolution.
A strong signature of the 0-pi Josephson junction is demonstrated by measuring
the critical current as a function of two components (B_x, B_y) of an in-plane
magnetic field. The experimental observation of a half-integer zero field step
in 0-pi SIFS junctions is presented.


title:
A ~5 M_earth Super-Earth Orbiting GJ 436?: The Power of Near-Grazing
  Transits

abstract:
  Most of the presently identified exoplanets have masses similar to that of
Jupiter and therefore are assumed to be gaseous objects. With the
ever-increasing interest in discovering lower-mass planets, several of the
so-called super-Earths (1 M_earth<M<10 M_earth), which are predicted to be
rocky, have already been found. Here we report the possible discovery of a
planet around the M-type star GJ 436 with a minimum mass of 4.7+/-0.6 M_earth
and a true mass of ~5 M_earth, which would make it the least massive planet
around a main-sequence star found to date. The planet is identified from its
perturbations on an inner Neptune-mass transiting planet (GJ 436b), by pumping
eccentricity and producing variations in the orbital inclination. Analysis of
published radial velocity measurements indeed reveals a significant signal
corresponding to an orbital period that is very close to the 2:1 mean motion
resonance with the inner planet. The near-grazing nature of the transit makes
it extremely sensitive to small changes in the inclination.


title: Oblique Hanle Effect in Semiconductor Spin Transport Devices

abstract:
  Spin precession and dephasing ("Hanle effect") provides an unambiguous means
to establish the presence of spin transport in semiconductors. We compare
theoretical modeling with experimental data from drift-dominated silicon
spin-transport devices, illustrating the non-trivial consequences of employing
oblique magnetic fields (due to misalignment or intentional, fixed in-plane
field components) to measure the effects of spin precession. Model results are
also calculated for Hanle measurements under conditions of diffusion-dominated
transport, revealing an expected Hanle peak-widening effect induced by the
presence of fixed in-plane magnetic bias fields.


title:
NNLO predictions for the Higgs boson signal in the H->WW->lnu lnu and
  H->ZZ->4l decay channels

abstract:
  We consider Standard Model Higgs boson production by gluon--gluon fusion in
hadron collisions. We present a calculation of the next-to-next-to-leading
order QCD corrections to the cross section in the H->WW->lnu lnu and H->ZZ->4l
decay channels. The calculation is implemented in the parton level Monte Carlo
program HNNLO and allows us to apply arbitrary cuts on the final state leptons
and the associated jet activity. We present selected numerical results for the
signal cross section at the LHC, by using all the nominal cuts proposed for the
forthcoming Higgs boson search.


title: Twisted Deformation Quantization of Algebraic Varieties (Survey)

abstract:
  Let X be a smooth algebraic variety over a field of characteristic 0. We
introduce the notion of twisted associative (resp. Poisson) deformation of the
structure sheaf O_X. These are stack-like versions of usual deformations. We
prove that there is a twisted quantization map from twisted Poisson
deformations to twisted associative deformations, which is canonical and
bijective on equivalence classes.


title:
Including stereoscopic information in the reconstruction of coronal
  magnetic fields

abstract:
  We present a method to include stereoscopic information about the three
dimensional structure of flux tubes into the reconstruction of the coronal
magnetic field. Due to the low plasma beta in the corona we can assume a force
free magnetic field, with the current density parallel to the magnetic field
lines. Here we use linear force free fields for simplicity. The method uses the
line of sight magnetic field on the photosphere as observational input. The
value of $\alpha$ is determined iteratively by comparing the reconstructed
magnetic field with the observed structures. The final configuration is the
optimal linear force solution constrained by both the photospheric magnetogram
and the observed plasma structures. As an example we apply our method to SOHO
MDI/EIT data of an active region. In the future it is planned to apply the
method to analyse data from the SECCHI instrument aboard the STEREO mission.


title: Neutron contribution to nuclear DVCS asymmetries

abstract:
  Using a simple model for nuclear GPDs, we study the role of the neutron
contribution to nuclear DVCS observables. As an example, we use the beam-spin
asymmetry A_{LU}^A measured in coherent and incoherent DVCS on a wide range of
nuclear targets in the HERMES and JLab kinematics. We find that at small values
of the momentum transfer t, A_{LU}^A is dominated by the coherent-enriched
contribution, which enhances A_{LU}^A compared to the free proton asymmetry
A_{LU}^p, A_{LU}^A(\phi)/A_{LU}^p(\phi)=1.8-2.2. At large values of t, the
nuclear asymmetry is dominated by the incoherent contribution and
A_{LU}^A/(\phi)A_{LU}^p(\phi)=0.66-0.74. The deviation of
A_{LU}^A(\phi)/A_{LU}^p(\phi) from unity at large t is a result of the neutron
contribution, which gives a possibility to constain neutron GPDs in incoherent
nuclear DVCS. A similar trend is expected for other DVCS asymmetries.


title: Beilinson's Hodge Conjecture for K_1 revisited

abstract:
  Let U be a smooth quasiprojective complex variety and CH^r(U,1) a special
instance of Bloch's higher Chow groups. Jannsen was the first to show that the
cycle class map cl_{r,1} from CH^r(U,1) (tensored with Q) to hom_{MHS}(Q(0),
H^{2r-1}(U,Q(r)) is not in general surjective, contradicting an earlier
conjecture of Beilinson. In this paper, we give a refinement of Jannsen's
counterexample, and further show that the aforementioned cycle class map
becomes surjective at the generic point.


title:
Nonlinear force-free magnetic field extrapolations: comparison of the
  Grad-Rubin and Wheatland-Sturrock-Roumeliotis algorithm

abstract:
  We compare the performance of two alternative algorithms which aim to
construct a force-free magnetic field given suitable boundary conditions. For
this comparison, we have implemented both algorithms on the same finite element
grid which uses Whitney forms to describe the fields within the grid cells. The
additional use of conjugate gradient and multigrid iterations result in quite
effective codes. The Grad-Rubin and Wheatland-Sturrock-Roumeliotis algorithms
both perform well for the reconstruction of a known analytic force-free field.
For more arbitrary boundary conditions the Wheatland-Sturrock-Roumeliotis
approach has some difficulties because it requires overdetermined boundary
information which may include inconsistencies. The Grad-Rubin code on the other
hand loses convergence for strong current densities. For the example we have
investigated, however, the maximum possible current density seems to be not far
from the limit beyond which a force free field cannot exist anymore for a given
normal magnetic field intensity on the boundary.


title:
Rapidly-converging methods for the location of quantum critical points
  from finite-size data

abstract:
  We analyze in detail, beyond the usual scaling hypothesis, the finite-size
convergence of static quantities toward the thermodynamic limit. In this way we
are able to obtain sequences of pseudo-critical points which display a faster
convergence rate as compared to currently used methods. The approaches are
valid in any spatial dimension and for any value of the dynamic exponent. We
demonstrate the effectiveness of our methods both analytically on the basis of
the one dimensional XY model, and numerically considering c = 1 transitions
occurring in non integrable spin models. In particular, we show that these
general methods are able to locate precisely the onset of the
Berezinskii-Kosterlitz-Thouless transition making only use of ground-state
properties on relatively small systems.


title:
Online-concordance "Perekhresni stezhky" ("The Cross-Paths"), a novel by
  Ivan Franko

abstract:
  In the article, theoretical principles and practical realization for the
compilation of the concordance to "Perekhresni stezhky" ("The Cross-Paths"), a
novel by Ivan Franko, are described. Two forms for the context presentation are
proposed. The electronic version of this lexicographic work is available
online.


title: Segmentation of Loops from Coronal EUV Images

abstract:
  We present a procedure which extracts bright loop features from solar EUV
images. In terms of image intensities, these features are elongated ridge-like
intensity maxima. To discriminate the maxima, we need information about the
spatial derivatives of the image intensity. Commonly, the derivative estimates
are strongly affected by image noise. We therefore use a regularized estimation
of the derivative which is then used to interpolate a discrete vector field of
ridge points ``ridgels'' which are positioned on the ridge center and have the
intrinsic orientation of the local ridge direction. A scheme is proposed to
connect ridgels to smooth, spline-represented curves which fit the observed
loops. Finally, a half-automated user interface allows one to merge or split,
eliminate or select loop fits obtained form the above procedure. In this paper
we apply our tool to one of the first EUV images observed by the SECCHI
instrument onboard the recently launched STEREO spacecraft. We compare the
extracted loops with projected field lines computed from
almost-simultaneously-taken magnetograms measured by the SOHO/MDI Doppler
imager. The field lines were calculated using a linear force-free field model.
This comparison allows one to verify faint and spurious loop connections
produced by our segmentation tool and it also helps to prove the quality of the
magnetic-field model where well-identified loop structures comply with
field-line projections. We also discuss further potential applications of our
tool such as loop oscillations and stereoscopy.


title:
The Tidal Streams of Disrupting Subhaloes in Cosmological Dark Matter
  Haloes

abstract:
  (abridged) We present a detailed analysis of the properties of tidally
stripped material from disrupting substructure haloes or subhaloes in a sample
of high resolution cosmological N-body host haloes ranging from galaxy- to
cluster-mass scales. We focus on devising methods to recover the infall mass
and infall eccentricity of subhaloes from the properties of their tidally
stripped material (i.e. tidal streams). Our analysis reveals that there is a
relation between the scatter of stream particles about the best-fit debris
plane and the infall mass of the progenitor subhalo. This allows us to
reconstruct the infall mass from the spread of its tidal debris in space. We
also find that the spread in radial velocities of the debris material (as
measured by an observer located at the centre of the host) correlates with the
infall eccentricity of the subhalo, which allows us to reconstruct its orbital
parameters. We devise an automated method to identify leading and trailing arms
that can, in principle at least, be applied to observations of stellar streams
from satellite galaxies. This method is based on the energy distribution of
material in the tidal stream. Using this method, we show that the mass
associated with leading and trailing arms differ. While our analysis indicates
that tidal streams can be used to recover certain properties of their
progenitor subhaloes (and consequently satellites), we do not find strong
correlations between host halo properties and stream properties. This likely
reflects the complicated relationship between the stream and the host, which in
a cosmological context is characterised by a complex mass accretion history, an
asymmetric mass distribution and the abundance of substructure. [...]


title:
Inhomogeneous Light Shift Effects on Atomic Quantum State Evolution in
  Non-Destructive Measurements

abstract:
  Various parameters of a trapped collection of cold and ultracold atoms can be
determined non--destructively by measuring the phase shift of an off--resonant
probe beam, caused by the state dependent index of refraction of the atoms. The
dispersive light--atom interaction, however, gives rise to a differential light
shift (AC Stark shift) between the atomic states which, for a nonuniform probe
intensity distribution, causes an inhomogeneous dephasing between the atoms. In
this paper, we investigate the effects of this inhomogeneous light shift in
non--destructive measurement schemes. We interpret our experimental data on
dispersively probed Rabi oscillations and Ramsey fringes in terms of a simple
light shift model which is shown to describe the observed behavior well.
Furthermore, we show that by using spin echo techniques, the inhomogeneous
phase shift distribution between the two clock levels can be reversed.