title:
Universal Correlations and Dynamic Disorder in a Nonlinear Periodic 1D
  System

abstract:
  When a periodic 1D system described by a tight-binding model is uniformly
initialized with equal amplitudes at all sites, yet with completely random
phases, it evolves into a thermal distribution with no spatial correlations.
However, when the system is nonlinear, correlations are spontaneously formed.
We find that for strong nonlinearities, the intensity histograms approach a
narrow Gaussian distributed around their mean and phase correlations are formed
between neighboring sites. Sites tend to be out-of-phase for a positive
nonlinearity and in-phase for a negative one. The field correlations take a
universal shape independent of parameters. This nonlinear evolution produces an
effectively dynamically disordered potential which exhibits interesting
diffusive behavior.


title: A Note on Self-Dual Yang-Mills Theory

abstract:
  We translate the classical Atiyah-Ward correspondence into the L-infinity
language. We extend the correspondence to a quasi-isomorphism between the
algebra of the self-dual four-manifold X and the algebra of the holomorphic
BF-theory in the twistor space T(X).


title: Parity condition for irreducibility of Heegaard splittings

abstract:
  Casson and Gordon gave the rectangle condition for strong irreducibility of
Heegaard splittings [1]. We give a parity condition for irreducibility of
Heegaard splittings of irreducible manifolds. As an application, we give
examples of non-stabilized Heegaard splittings by doing a single Dehn twist.


title:
Modelling two-dimensional Crystals with Defects under Stress:
  Superelongation of Carbon Nanotubes at high Temperatures

abstract:
  We calculate analytically the phase diagram of a two-dimensional square
crystal and its wrapped version with defects under external homogeneous stress
as a function of temperature using a simple elastic lattice model that allows
for defect formation. The temperature dependence turns out to be very weak. The
results are relevant for recent stress experiments on carbon nanotubes. Under
increasing stress, we find a crossover regime which we identify with a cracking
transition that is almost independent of temperature. Furthermore, we find an
almost stress-independent melting point. In addition, we derive an enhanced
ductility with relative strains before cracking between 200-400%, in agreement
with carbon nanotube experiments. The specific values depend on the Poisson
ratio and the angle between the external force and the crystal axes. We give
arguments that the results for carbon nanotubes are not much different to the
wrapped square crystal.


title: A comment on $p$-branes of ($p+3$)$\rm{d}$ string theory

abstract:
  We argue that in ($p+3$)d string theory the existence of NS-NS type $p$-brane
with negative tension is essential to obtain background geometry $R_2$ or $R_2
/ Z_n$ on the transverse dimensions, and the usual codimension-2 brane
solutions with these background geometries already contain the negative tension
NS-brane implicity in their ansatz. Such an argument leads us, in the context
of brane world scenarios, to a conjecture that true background $p$-brane
immanent in our spacetime may perhaps be NS-NS type brane, rather than D-brane.


title: Gauge Orbit Types for Theories with Classical Compact Gauge Group

abstract:
  We determine the orbit types of the action of the group of local gauge
transformations on the space of connections in a principal bundle with
structure group O(n), SO(n) or $Sp(n)$ over a closed, simply connected manifold
of dimension 4. Complemented with earlier results on U(n) and SU(n) this
completes the classification of the orbit types for all classical compact gauge
groups over such space-time manifolds. On the way we derive the classification
of principal bundles with structure group SO(n) over these manifolds and the
Howe subgroups of SO(n).


title:
Monotonicity theorems for Laplace Beltrami operator on Riemannian
  manifolds

abstract:
  For free boundary problems on Euclidean spaces, the monotonicity formulas of
Alt-Caffarelli-Friedman and Caffarelli-Jerison-Kenig are cornerstones for the
regularity theory as well as the existence theory. In this article we establish
the analogs of these results for the Laplace-Beltrami operator on Riemannian
manifolds. As an application we show that our monotonicity theorems can be
employed to prove the Lipschitz continuity for the solutions of a general class
of two-phase free boundary problems on Riemannian manifolds.


title: CP asymmetry in $B^{+}\to K^+\pi^{0}$ and New Physics

abstract:
  The CP asymmetry in $B^0\to K^+\pi^-$ is expected to be similar to that in
$B^+\to K^+\pi^0$. The experimental data however show $\sim 5\sigma$ difference
between the two, leading to the so called $\Delta {A}_{K\pi}$ puzzle. Employing
sum rule(s) following from (approximate) flavour symmetry, we show that it is
possible to accommodate the observed experimental values within the standard
model (SM) for a narrow range of parameters. Sub-leading terms can bring the
theoretical predictions in better agreement with the data. Resolution via
modified electroweak penguin contributions is possible for a large CP violating
phase generated by the new physics. However, the data on polarization in $B\to
VV(T)$, $B_s$-$\bar{B}_s$ mixing (and large CP phase) and
$B^+\to\tau^+\nu_{\tau}$ rate can not be simultaneously accommodated within SM
or new physics with only enhanced electroweak penguins. A plausible resolution
to these, and not spoiling the $B\to K\pi$ rates and asymmetries, could be a
general two Higgs doublet model.


title:
Measurement of the quadratic Zeeman shift of ^{85}Rb hyperfine sublevels
  using stimulated Raman transitions

abstract:
  We demonstrate a technique for directly measuring the quadratic Zeeman shift
using stimulated Raman transitions.The quadratic Zeeman shift has been measured
yielding [delta][nju] = 1296.8 +/-3.3 Hz/G^{2} for magnetically insensitive
sublevels (5S1/2, F = 2,mF = 0 -> 5S1/2, F = 3,mF = 0) of ^{85}Rb by
compensating the magnetic eld and cancelling the ac Stark shift. We also
measured the cancellation ratio of the differential ac Stark shift due to the
imbalanced Raman beams by using two pairs of Raman beams ([sigma]^{+},
[sigma]^{+}) and it is 1:3.67 when the one-photon detuning is 1.5 GHz in the
experiment.


title:
Higher Angular Momentum Mixing in a Non-spherical Color Superconductor
  with Time Reversal Invariance Violation

abstract:
  The angular momentum mixing in a non-spherical CSC with nonzero azimuthal
quantum number and therefore violating time reversal invariance has been
examined. The mixing is bound to occur because of the equal strength of the
pairing potential mediated by one-gluon exchange for all partial waves to the
leading order QCD running coupling constant and the nonlinearity of the gap
equation. The free energy with mixing is lower than that with p-wave pairing
only, but still higher than that of the spherical CSL state.


title:
Rotation Symmetry Spontaneous Breaking of Edge States in Zigzag Carbon
  Nanotubes

abstract:
  Analytical solutions of the edge states were obtained for the (N, 0) type
carbon nanotubes with distorted ending bonds. It was found that the edge states
are mixed via the distortion. The total energies for N=5 and N>=7 are lower in
the asymmetric configurations of ending bonds than those having axial rotation
symmetry. Thereby the symmetry is breaking spontaneously. The results imply
that the symmetry of electronic states at the apex depends on the occupation;
the electron density pattern at the apex could change dramatically and could be
controlled by applying an external field.


title:
Tuning the bond order wave (BOW) phase of half-filled extended Hubbard
  models

abstract:
  Theoretical and computational studies of the quantum phase diagram of the
one-dimensional half-filled extended Hubbard model (EHM) indicate a narrow bond
order wave (BOW) phase with finite magnetic gap $E_m$ for on-site repulsion $U
< U^*$, the critical point, and nearest neighbor interaction $V_c \approx U/2$
near the boundary of the charge density wave (CDW) phase. Potentials with more
extended interactions that retain the EHM symmetry are shown to have a less
cooperative CDW transition with higher $U^*$ and wider BOW phase. Density
matrix renormalization group (DMRG) is used to obtain $E_m$ directly as the
singlet-triplet gap, with finite $E_m$ marking the BOW boundary $V_s(U)$. The
BOW/CDW boundary $V_c(U)$ is obtained from exact finite-size calculations that
are consistent with previous EHM determinations. The kinetic energy or bond
order provides a convenient new estimate of $U^*$ based on a metallic point at
$V_c(U)$ for $U < U^*$. Tuning the BOW phase of half-filled Hubbard models with
different intersite potentials indicates a ground state with large charge
fluctuations and magnetic frustration. The possibility of physical realizations
of a BOW phase is raised for Coulomb interactions.


title: Geodesics and Symmetries of Doubly-Spinning Black Rings

abstract:
  This paper studies various properties of the Pomeransky-Sen'kov
doubly-spinning black ring spacetime. I discuss the structure of the
ergoregion, and then go on to demonstrate the separability of the
Hamilton-Jacobi equation for null, zero energy geodesics, which exist in the
ergoregion. These geodesics are used to construct geometrically motivated
coordinates that cover the black hole horizon. Finally, I relate this weak form
of separability to the existence of a conformal Killing tensor in a particular
4-dimensional spacetime obtained by Kaluza-Klein reduction, and show that a
related conformal Killing-Yano tensor only exists in the singly-spinning case.


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

abstract:
  New measurements of the total and partial fragmentation cross sections in the
energy range 0.3-10 A GeV of Fe^{26+}, Si^{14+} and C^{6+} beams on
polyethylene, CR39 and aluminum targets are presented. The exposures were made
at Brookhaven National Laboratory (BNL), USA, and Heavy Ion Medical Accelerator
in Chiba (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: Quark and Gluon Condensates in Isospin Matter

abstract:
  Applying the Hellmann-Feynman theorem to a charged pion gas, the quark and
gluon condensates at low isospin density are determined by precise pion
properties. At intermediate density around $ f_\pi^2m_\pi$, from both the
estimation for the dilute pion gas and the calculation with Nambu--Jona-Lasinio
model, the quark condensate is strongly and monotonously suppressed, while the
gluon condensate is enhanced and can be larger than its vacuum value. This
unusual behavior of the gluon condensate is universal for Bose condensed matter
of mesons. Our results can be tested by lattice calculations at finite isospin
density.


title:
Quantum violation of macroscopic realism and the transition to classical
  physics

abstract:
  The descriptions of the quantum realm and the macroscopic classical world
differ significantly not only in their mathematical formulations but also in
their foundational concepts and philosophical consequences. When and how
physical systems stop to behave quantum mechanically and begin to behave
classically is still heavily debated in the physics community and subject to
theoretical and experimental research.
  This dissertation puts forward an approach to the quantum-to-classical
transition fully within quantum theory and conceptually different from already
existing models: It neither needs to refer to the uncontrollable environment of
a system (decoherence) nor to change the quantum laws itself (collapse models),
but puts the stress on the limits of observability of quantum phenomena due to
the imprecision of our measurement apparatuses. For a certain class of time
evolutions it is this mere restriction to coarse-grained measurements which is
sufficient to see the natural emergence of macroscopic realism and even the
classical Newtonian laws out of the full quantum formalism. But there also
exist "non-classical" Hamiltonians for which a classical spatiotemporal
description of the system's time evolution remains impossible even under fuzzy
measurements or decoherence. It is argued that such Hamiltonians are unlikely
to be spontaneously realized in nature because of their high complexity.
  The last part addresses the question of the origin of quantum randomness and
proposes a link with mathematical undecidability.


title: Collective modes of trapped Fermi gases with in-medium interaction

abstract:
  Due to Pauli blocking of intermediate states, the scattering matrix (or $T$
matrix) of two fermionic atoms in a Fermi gas becomes different from that of
two atoms in free space. This effect becomes particularly important near a
Feshbach resonance, where the interaction in free space is very strong but
becomes effectively suppressed in the medium. We calculate the in-medium $T$
matrix in ladder approximation and study its effects on the properties of
collective modes of a trapped gas in the normal-fluid phase. We introduce the
in-medium interaction on both sides of the Boltzmann equation, namely in the
calculation of the mean field and in the calculation of the collision rate.
This allows us to explain the observed upward shift of the frequency of the
quadrupole mode in the collisionless regime. By including the mean field, we
also improve considerably the agreement with the measured temperature
dependence of frequency and damping rate of the scissors mode, whereas the use
of the in-medium cross section deteriorates the description, in agreement with
previous work.


title: On the Flow of Time

abstract:
  Current theoretical physics suggests the flow of time is an illusion: the
entire universe just is, with no special meaning attached to the present time.
This paper points out that this view, in essence represented by usual
space-time diagrams, is based on time-reversible microphysical laws, which fail
to capture essential features of the time-irreversible nature of decoherence
and the quantum measurement process, as well as macro-physical behaviour and
the development of emergent complex systems, including life, which exist in the
real universe. When these are taken into account, the unchanging block universe
view of spacetime is best replaced by an evolving block universe which extends
as time evolves, with the potential of the future continually becoming the
certainty of the past; spacetime itself evolves, as do the entities within it.
However this time evolution is not related to any preferred surfaces in
spacetime; rather it is associated with the evolution of proper time along
families of world lines. The default state of fundamental physics should not be
taken to be a time irreversible evolution of physical states: it is an ongoing
irreversible development of time itself.


title:
Possible Quasi-Periodic Oscillations from Unstable Accretion: 3D MHD
  Simulations

abstract:
  We investigate the photometric variability of magnetized stars, particularly
neutron stars, accreting through a magnetic Rayleigh-Taylor-type instability at
the disk-magnetosphere interface, and compare it with the variability during
stable accretion, with the goal of looking for possible quasi-periodic
oscillations. The lightcurves during stable accretion show periodicity at the
star's frequency and sometimes twice that, due to the presence of two funnel
streams that produce antipodal hotspots near the magnetic poles. On the other
hand, lightcurves during unstable accretion through tongues penetrating the
magnetosphere are more chaotic due to the stochastic behaviour of the tongues,
and produce noisier power spectra. However, the power spectra do show some
signs of quasi-periodic variability. Most importantly, the rotation frequency
of the tongues and the resulting hotspots is close to the inner-disk orbital
frequency, except in the most strongly unstable cases. There is therefore a
high probability of observing QPOs at that frequency in longer simulations. In
addition, the lightcurves in the unstable regime show periodicity at the star's
rotation frequency in many of the cases investigated here, again except in the
most strongly unstable cases which lack funnel flows and the resulting
antipodal hotspots. The noisier power spectra result in the fractional rms
amplitudes of the Fourier peaks being smaller.
  We also study in detail the effect of the misalignment angle between the
rotation and magnetic axes of the star on the variability, and find that at
misalignment angles $\gtrsim 25^\circ$, the star's period always appears in the
lightcurves.


title: On the behaviour of stellar winds that exceed the photon-tiring limit

abstract:
  Stars can produce steady-state winds through radiative driving as long as the
mechanical luminosity of the wind does not exceed the radiative luminosity at
its base. This upper bound on the mass loss rate is known as the photon-tiring
limit. Once above this limit, the radiation field is unable to lift all the
material out of the gravitational potential of the star, such that only part of
it can escape and reach infinity. The rest stalls and falls back toward the
stellar surface, making a steady-state wind impossible. Photon-tiring is not an
issue for line-driven winds since they cannot achieve sufficiently high mass
loss rates. It can however become important if the star exceeds the Eddington
limit and continuum interaction becomes the dominant driving mechanism.
  This paper investigates the time-dependent behaviour of stellar winds that
exceed the photon-tiring limit, using 1-D numerical simulations of a porosity
moderated, continuum-driven stellar wind. We find that the regions close to the
star show a hierarchical pattern of high density shells moving back and forth,
unable to escape the gravitational potential of the star. At larger distances,
the flow eventually becomes uniformly outward, though still quite variable.
Typically, these winds have a very high density but a terminal flow speed well
below the escape speed at the stellar surface. Since most of the radiative
luminosity of the star is used to drive the stellar wind, such stars would
appear much dimmer than expected from the super-Eddington energy generation at
their core. The visible luminosity typically constitutes less then half of the
total energy flow and can become as low as ten percent or less for those stars
that exceed the photon-tiring limit by a large margin.


title: Causal boundaries and holography on wave type spacetimes

abstract:
  The notion of a causal boundary for a spacetime has been a controversial
topic during the last three decades. Moreover, recently the role of the
boundary in the AdS/CFT correspondence for plane waves, have stimulated its
redefinition with some possible alternatives.
  Our aim is threefold. First, to review the different classical approaches to
boundaries of spacetimes, emphasizing their drawbacks and the progressive
redefinitions of the c-boundary. Second, to explain how plane waves and AdS/CFT
correspondence come into play, stressing the role of the c-boundary as the
holographic boundary in this correspondence. And, third, to discuss the
present-day status of the c-boundary, making clear the arguments of a
definitive proposal.


title:
Efficient implementation of a van der Waals density functional:
  Application to double-wall carbon nanotubes

abstract:
  We present an efficient implementation of the van der Waals density
functional of Dion et al [Phys. Rev. Lett. 92, 246401 (2004)], which expresses
the nonlocal correlation energy as a double spacial integral. We factorize the
integration kernel and use fast Fourier transforms to evaluate the
selfconsistent potential, total energy, and atomic forces, in N log(N)
operations. The resulting overhead in total computational cost, over semilocal
functionals, is very moderate for medium and large systems. We apply the method
to calculate the binding energies and the barriers for relative translation and
rotation in double-wall carbon nanotubes.


title: Nano-scale brushes: How to build a smart surface coating

abstract:
  Via computer simulations, we demonstrate how a densely grafted layer of
polymers, a {\it brush}, could be turned into an efficient switch through
chemical modification of some of its end-monomers. In this way, a surface
coating with reversibly switchable properties can be constructed. We analyze
the fundamental physical principle behind its function, a recently discovered
surface instability, and demonstrate that the combination of a high grafting
density, an inflated end-group size and a high degree of monodispersity are
conditions for an optimal functionality of the switch.


title:
Bose-Einstein condensate in a quartic potential: Static and Dynamic
  properties

abstract:
  In this paper, we present a theoretical study of a Bose-Einstein condensate
of interacting bosons in a quartic trap in one, two, and three dimensions.
Using Thomas-Fermi approximation, suitably complemented by numerical solutions
of the Gross-Pitaevskii equation, we study the ground sate condensate density
profiles, the chemical potential, the effects of cross-terms in the quartic
potential, temporal evolution of various energy components of the condensate,
and width oscillations of the condensate. Results obtained are compared with
corresponding results for a bose condensate in a harmonic confinement.


title: Neutron Stars as a Probe for Dense Matter

abstract:
  We study different stages of the neutron star cooling by computing neutron
star properties at various temperatures and entropies using an effective chiral
model including hadronic and quark degrees of freedom. Macroscopic properties
of the star such as mass and radius are calculated and compared with
observations. It can be seen that the effects of chiral restoration and
deconfinement to quark matter in the core of the neutron star at different
stages of the evolution can be significant for the evolution of the star and
allow insight into the behaviour of matter at extreme densities.


title: Gauge Coupling Unification in F-theory GUT Models

abstract:
  We investigate gauge coupling unification for F-theory respectively Type IIB
orientifold constructions of SU(5) GUT theories with gauge symmetry breaking
via non-trivial hypercharge flux. This flux has the non-trivial effect that it
splits the values of the three MSSM gauge couplings at the string scale, thus
potentially spoiling the celebrated one-loop gauge coupling unification. It is
shown how F-theory can evade this problem in a natural way.


title: F-Term Hybrid Inflation Followed by Modular Inflation

abstract:
  We consider the well motivated model of the (standard) supersymmetric F-term
hybrid inflation (FHI) which can be realized close to the grand unification
scale. The predicted scalar spectral index $n_s$ cannot be smaller than 0.98
and can exceed unity including corrections from minimal supergravity, if the
number of e-foldings corresponding to the pivot scale $k_*=0.002/{\rm Mpc}$ is
around 50. These results are marginally consistent with the fitting of the
Wilkinson microwave anisotropy probe data by the standard power-law
cosmological model with cold dark matter and a cosmological constant. However,
$n_s$ can be reduced by restricting the number of e-foldings that $k_*$
suffered during FHI. The additional e-foldings required for solving the horizon
and flatness problems can be generated by a subsequent stage of fast-roll
[slow-roll] modular inflation realized by a string modulus which does [does
not] acquire effective mass before the onset of modular inflation.


title: The Ages, Masses, Evolution and Kinematics of Mira variable

abstract:
  Evidence on the ages and masses of Mira variables is reviewed. Period
increases with increasing initial mass. Miras of logP about 3.0 have initial
masses of near 4 solar masses. It is suggestd that the apparent gap in the LMC
PL relation at about this period may be due to the onset of hot bottom burning
and that this adds about 15 to 20 percent to the stellar energy production.
Shorter period HBB stars are probably overtone pulsators. T Lep may be an
example of cool bottom processing.


title:
VLT/ISAAC Spectra of the Hbeta Region in Intermediate-Redshift Quasars
  III. Hbeta Broad Line Profile Analysis and Inferences about BLR Structure

abstract:
  [Abridged] We present new VLT ISAAC spectra for 30 quasars, which we combine
with previous data to yield a sample of 53 intermediate redshift (z ~ 0.9 -
3.0) sources. The sample is used to explore properties of prominent lines in
the Hbeta spectral region of these very luminous quasars. We find two major
trends: (1) a systematic increase of minimum FWHM Hbeta with luminosity
(discussed in a previous paper). This lower FWHM envelope is best fit assuming
that the narrowest sources radiate near the Eddington limit, show line emission
from a virialized cloud distribution, and obey a well defined broad line region
size vs. luminosity relation. (2) A systematic decrease of equivalent width of
[OIII] (from W ~ 15 to ~ 1 A) with increasing source bolometric luminosity
(from log L ~ 43 to log L ~ 49). Further identified trends required
discrimination between so-called Population A and B sources. We generate median
composite spectra in six luminosity bins Pop. A sources show reasonably
symmetric Lorentzian Hbeta profiles at all luminosities while Pop. B sources
require two component fits involving an unshifted broad and a redshifted very
broad component. Very broad Hbeta increases in strength with increasing L while
the broad component remains constant resulting in an apparent "Baldwin effect"
with equivalent width decreasing from W ~ 80 to ~ 20 A over our sample
luminosity range. The roughly constant equivalent width shown by the Hbeta very
broad component implies production in optically-thick, photoionized gas. The
onset of the redshifted very broad component appears to be a critical change
that occurs near the Pop. A-B boundary at FWHM Hbeta ~ 4000 km/s which we
relate to a critical Eddington ratio (~ 0.2 +/- 0.1).


title: Identification of Optimal Topography by Variational Data Assimilation

abstract:
  The use of data assimilation technique to identify optimal topography is
discussed in frames of time-dependent motion governed by non-linear barotropic
ocean model. Assimilation of artificially generated data allows to measure the
influence of various error sources and to classify the impact of noise that is
present in observational data and model parameters. The choice of assimilation
window is discussed. Assimilating noisy data with longer windows provides
higher accuracy of identified topography. The topography identified once by
data assimilation can be successfully used for other model runs that start from
other initial conditions and are situated in other parts of the model's
attractor.


title:
Calculation of geometrical and spin features of a series of
  metal-endofullerenes

abstract:
  A series of endofullerenes M@C60 were calculated from the first principles
(unrestricted Hartree Fock and DFT B3LYP) methods with effective core potential
(M = Ag, Cs) and all-electronic basis set (M = Li, Na, Cu). An arbitrary
symmetry distortion (down to C1 point group) was assumed. The geometrical and
electronic properties of M@C60 are compared for this series of endoatoms
including the off-center position of enoatoms within C60, effective charges and
spin density. The latter values are featured for Ag@C60 and Cu@C60.


title: On the Adams-Riemann-Roch theorem in positive characteristic

abstract:
  We give a new proof of the Adams-Riemann-Roch theorem for a smooth projective
morphism $X\to Y$, in the situation where $Y$ is a regular scheme, which is
quasi-projective over $\mF_p$. We also partially answer a question of B.
K\"ock.


title: From Vicious Walkers to TASEP

abstract:
  We propose a model of semi-vicious walkers, which interpolates between the
totally asymmetric simple exclusion process and the vicious walkers model,
having the two as limiting cases. For this model we calculate the asymptotics
of the survival probability for $m$ particles and obtain a scaling function,
which describes the transition from one limiting case to another. Then, we use
a fluctuation-dissipation relation allowing us to reinterpret the result as the
particle current generating function in the totally asymmetric simple exclusion
process. Thus we obtain the particle current distribution asymptotically in the
large time limit as the number of particles is fixed. The results apply to the
large deviation scale as well as to the diffusive scale. In the latter we
obtain a new universal distribution, which has a skew non-Gaussian form. For
$m$ particles its asymptotic behavior is shown to be
$e^{-\frac{y^{2}}{2m^{2}}}$ as $y\to -\infty $ and
$e^{-\frac{y^{2}}{2m}}y^{-\frac{m(m-1)}{2}}$ as $y\to \infty $.


title:
Searching bifurcations in high-dimensional parameter space via a
  feedback loop breaking approach

abstract:
  Bifurcations leading to complex dynamical behaviour of non-linear systems are
often encountered when the characteristics of feedback circuits in the system
are varied. In systems with many unknown or varying parameters, it is an
interesting, but difficult problem to find parameter values for which specific
bifurcations occur. In this paper, we develop a loop breaking approach to
evaluate the influence of parameter values on feedback circuit characteristics.
This approach allows a theoretical classification of feedback circuit
characteristics related to possible bifurcations in the system. Based on the
theoretical results, a numerical algorithm for bifurcation search in a possibly
high-dimensional parameter space is developed. The application of the proposed
algorithm is illustrated by searching for a Hopf bifurcation in a model of the
mitogen activated protein kinase (MAPK) cascade, which is a classical example
for biochemical signal transduction.


title: Superembedding approach to superstring in AdS(5)xS*5 superspace

abstract:
  We review the spinor moving frame formulations and generalized action
principle for super-p-branes, describe in detail the superembedding approach to
superstring in general type IIB supergravity background and present the
complete superembedding description of type IIB superstring in the AdS(5)xS*5
superspace.


title:
A study of the possibility of sprites in the atmospheres of other
  planets

abstract:
  Sprites are a spectacular type of transient luminous events (TLE) which occur
above thunderstorms immediately after lightning. They have shapes of giant
jellyfish, carrots or columns and last tens of milliseconds. In Earth's
atmosphere, sprites mostly emit in red and blue wavelengths from excited N2 and
N2+ and span a vertical range between 50 and 90 km above the surface. The
emission spectra, morphology and occurrence heights of sprites reflect the
properties of the planetary atmosphere they inhabit and are related to the
intensity of the initiating parent lightning.. This paper presents results of
theoretical calculations of the expected occurrence heights of sprites above
lightning discharges in the CO2 atmosphere of Venus, the N2 atmosphere of Titan
and the H2-He atmosphere of Jupiter. The expected emission features are
presented and the potential of detecting sprites in planetary atmospheres by
orbiting spacecraft is discussed.


title: Representation dimension of extensions of hereditary algebras

abstract:
  We show that if H is a hereditary finite dimensional algebra, M is a finitely
generated H-module and B is a semisimple subalgebra of the endomorphism algebra
of M, then the representation dimension of the corresponding triangular matrix
algebra is less or equal to 3 whenever one of the following conditions hold: i)
H is of finite representation type; ii) H is tame and M is a direct sum of
regular and preprojective modules; iii) M has no self-extensions


title: Classical fields method for a relativistic interacting Bose gas

abstract:
  We formulate a classical fields method for description of relativistic
interacting bosonic particles at nonzero temperatures. The method relays on the
assumption that at low temperatures the Bose field can be described by a
c-number function. We discuss a very important role of the cut-off momentum
which divides the field into dominant classical part and a small quantum
correction. We illustrate the method by studying a thermodynamics of
relativistic Bose field which dynamics is governed by the Klein-Gordon equation
with $\lambda \psi^4$ term responsible for interactions.


title:
Cooling a micro-mechanical resonator by quantum back-action from a noisy
  qubit

abstract:
  We study the role of qubit dephasing in cooling a mechanical resonator by
quantum back-action. With a superconducting flux qubit as a specific example,
we show that ground-state cooling of a mechanical resonator can only be
realized if the qubit dephasing rate is sufficiently low.


title: An evaluation of Bradfordizing effects

abstract:
  The purpose of this paper is to apply and evaluate the bibliometric method
Bradfordizing for information retrieval (IR) experiments. Bradfordizing is used
for generating core document sets for subject-specific questions and to reorder
result sets from distributed searches. The method will be applied and tested in
a controlled scenario of scientific literature databases from social and
political sciences, economics, psychology and medical science (SOLIS, SoLit,
USB Koeln Opac, CSA Sociological Abstracts, World Affairs Online, Psyndex and
Medline) and 164 standardized topics. An evaluation of the method and its
effects is carried out in two laboratory-based information retrieval
experiments (CLEF and KoMoHe) using a controlled document corpus and human
relevance assessments. The results show that Bradfordizing is a very robust
method for re-ranking the main document types (journal articles and monographs)
in today's digital libraries (DL). The IR tests show that relevance
distributions after re-ranking improve at a significant level if articles in
the core are compared with articles in the succeeding zones. The items in the
core are significantly more often assessed as relevant, than items in zone 2
(z2) or zone 3 (z3). The improvements between the zones are statistically
significant based on the Wilcoxon signed-rank test and the paired T-Test.


title: Embeddings of k-connected n-manifolds into R^{2n-k-1}

abstract:
  We obtain estimations for isotopy classes of embeddings of closed k-connected
n-manifolds into R^{2n-k-1} for n>2k+5 and k\ge0. This is done in terms of an
exact sequence involving the Whitney invariants and an explicitly constructed
action of H_{k+1}(N;Z_2) on the set of embeddings. (For k\ne1 classification
results were obtained by algebraic methods without direct construction of
embeddings or homology invariants.)
  The proof involves reduction to classification of embeddings of punctured
manifold and uses parametric connected sum of embeddings.


title: Anisotropic non-Gaussianity from vector field perturbations

abstract:
  We suppose that a vector field perturbation causes part of the primordial
curvature perturbation. The non-Gaussianity parameter fNL is then, in general,
statistically anisotropic. We calculate its form and magnitude in the curvaton
scenario and in the end-of-inflation scenario. We show that this anisotropy
could easily be observable.


title: CP violation in charged Higgs boson decays

abstract:
  CP violation in H^\pm decays into the three possible decay modes into
ordinary particles, 1) H^\pm \to tb, 2) H^\pm \to \nu \tau and 3) H^\pm \to
W^\pm h^0 is considered. Analytic expressions and numerical results for the CP
violating decay rate asymmetries in the MSSM are obtained. Increasing \tan\beta
the asymmetries for the fermionic decays, H^\pm \to tb and H^\pm \to \nu \tau,
decrease and it increases for H^\pm \to W^\pm h^0. The asymmetry of H^\pm \to
tb is most sensitive to the phase of $A_t and can go up to 20%, the asymmetries
of 2) and 3) depend mainly on the phases of A_\tau and M_1. The asymmetry of 2)
is smaller than 0.5% and of 3) can reach up to 2%.


title: Threshold of a Random Laser with Cold Atoms

abstract:
  We address the problem of achieving an optical random laser with a cloud of
cold atoms, in which gain and scattering are provided by the same atoms. The
lasing threshold can be defined using the on-resonance optical thickness b0 as
a single critical parameter. We predict the threshold quantitatively, as well
as power and frequency of the emitted light, using two different light
transport models and the atomic polarizability of a strongly-pumped two-level
atom. We find a critical b0 on the order of 300, which is within reach of
state-of-the-art cold-atom experiments. Interestingly, we find that random
lasing can already occur in a regime of relatively low scattering.


title:
Search for Charged Higgs Bosons in e+e- Collisions at sqrts(s) = 189-209
  GeV

abstract:
  A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet
extensions of the Standard Model (2HDM) using electron-positron collision data
collected by the OPAL experiment at sqrt(s)=189-209 GeV, corresponding to an
integrated luminosity of approximately 600 pb-1. Charged Higgs bosons are
assumed to be pair-produced and to decay into q qbar, tau nu or A W+-. No
signal is observed. Model-independent limits on the charged Higgs-boson
production cross section are derived by combining these results with previous
searches at lower energies. Under the assumption BR(H+- -> tau nu) + BR(H+- ->
qq)=1, motivated by general 2HDM type II models, excluded areas on the [m(H+-),
BR(H+- -> tau nu)] plane are presented and charged Higgs bosons are excluded up
to a mass of 76.3 GeV at 95% confidence level, independent of the branching
ratio BR(H+- -> tau nu). A scan of the 2HDM type I model parameter space is
performed and limits on the Higgs-boson masses m(H+-) and m(A) are presented
for different choices of tan(beta).


title: Drag force on an oscillating object in quantum turbulence

abstract:
  This paper reports results of the computation of the drag force exerted on an
oscillating object in quantum turbulence in superfluid $^4$He. The drag force
is calculated on the basis of numerical simulations of quantum turbulent flow
about the object. The drag force is proportional to the square of the magnitude
of the oscillation velocity, which is similar to that in classical turbulence
at high Reynolds number. The drag coefficient is also calculated, and its value
is found to be of the same order as that observed in previous experiments. The
correspondence between quantum and classical turbulences is further clarified
by examining the turbulence created by oscillating objects.


title: Carbon isotope fractionation in protoplanetary disks

abstract:
  We investigate the gas-phase and grain-surface chemistry in the inner 30 AU
of a typical protoplanetary disk using a new model which calculates the gas
temperature by solving the gas heating and cooling balance and which has an
improved treatment of the UV radiation field. We discuss inner-disk chemistry
in general, obtaining excellent agreement with recent observations which have
probed the material in the inner regions of protoplanetary disks. We also apply
our model to study the isotopic fractionation of carbon. Results show that the
fractionation ratio, 12C/13C, of the system varies with radius and height in
the disk. Different behaviour is seen in the fractionation of different
species. We compare our results with 12C/13C ratios in the Solar System comets,
and find a stark contrast, indicative of reprocessing.


title: Varying and inverting the mass hierarchy in collisional energy loss

abstract:
  Heavy ion collisions at RHIC and at the LHC give access to the medium-induced
suppression patterns of heavy-flavored single inclusive hadron spectra at high
transverse momentum. This opens novel opportunities for a detailed
characterization of the medium produced in the collision. In this note, we
point out that the capacity of a QCD medium to absorb the recoil of a partonic
projectile is an independent signature, which may differ for different media at
the same density. In particular, while the mass hierarchy (i.e., the projectile
mass dependence) of radiative energy loss depends solely on a property of the
projectile, the mass hierarchy of collisional energy loss depends significantly
on properties of the medium. By varying these properties in a class of models,
we find that the mass hierarchy of collisional parton energy loss can be
modified considerably and can even be inverted, compared to that of radiative
parton energy loss. This may help to disentangle the relative strengths of
radiative and collisional contributions to jet quenching, and it may be
employed to constrain properties of the produced QCD medium beyond its density.


title:
Une conjecture sur la torsion des classes de Chern des fibr\'es de
  Gauss-Manin

abstract:
  Pour tout $t\in\mN$ nous d\'efinissons un certain entier positif $\N_t$ et
nous conjecturons: si $H$ est un fibr\'e de Gauss-Manin d'une fibration
semi-stable alors la $t$-\`eme classe de Chern de $H$ est annul\'ee par $\N_t$.
Nous d\'emontrons diverses cons\'equences de cette conjecture.
  For any $t\in\mN$, we define a certain positive integer $\N_t$ and we
conjecture: if $H$ is a Gauss-Manin bundle of a semi-stable fibration then the
$t$-th Chern class of $H$ is kiled by $\N_t$. We prove various consequences of
this conjecture.


title:
On the resolution of the big bang singularity in isotropic Loop Quantum
  Cosmology

abstract:
  In contrast to previous work in the field, we construct the Loop Quantum
Cosmology (LQC) of the flat isotropic model with a massless scalar field in the
absence of higher order curvature corrections to the gravitational part of the
Hamiltonian constraint. The matter part of the constraint contains the inverse
triad operator which can be quantized with or without the use of a Thiemann-
like procedure. With the latter choice, we show that the LQC quantization is
identical to that of the standard Wheeler DeWitt theory (WDW) wherein there is
no singularity resolution. We argue that the former choice leads to singularity
resolution in the sense of a well defined, regular (backward) evolution through
and beyond the epoch where the size of the universe vanishes.
  Our work along with that of the seminal work of Ashtekar, Pawlowski and Singh
(APS) clarifies the role, in singularity resolution, of the three `exotic'
structures in this LQC model, namely: curvature corrections, inverse triad
definitions and the `polymer' nature of the kinematic representation. We also
critically examine certain technical assumptions made by APS in their analysis
of WDW semiclassical states and point out some problems stemming from the
infrared behaviour of their wave functions


title: Entanglement of bosonic modes of nonplanar molecules

abstract:
  Entanglement of bosonic modes of material oscillators is studied in the
context of two bilinearly coupled, nonlinear oscillators. These oscillators are
realizable in the vibrational-cum-bending motions of C-H bonds in
dihalomethanes. The bilinear coupling gives rise to invariant subspaces in the
Hilbert space of the two oscillators. The number of separable states in any
invariant subspace is one more than the dimension of the space. The dynamics of
the oscillators when the initial state belongs to an invariant subspace is
studied. In particular, the dynamics of the system when the initial state is
such that the total energy is concentrated in one of the modes is studied and
compared with the evolution of the system when the initial state is such
wherein the modes share the total energy. The dynamics of quantities such as
entropy, mean of number of quanta in the two modes and variances in the
quadratures of the two modes are studied. Possibility of generating maximally
entangled states is indicated.


title: Bose Einstein condensation on inhomogeneous amenable graphs

abstract:
  We investigate the Bose-Einstein Condensation on nonhomogeneous amenable
networks for the model describing arrays of Josephson junctions. The resulting
topological model, whose Hamiltonian is the pure hopping one given by the
opposite of the adjacency operator, has also a mathematical interest in itself.
We show that for the nonhomogeneous networks like the comb graphs, particles
condensate in momentum and configuration space as well. In this case different
properties of the network, of geometric and probabilistic nature, such as the
volume growth, the shape of the ground state, and the transience, all play a
role in the condensation phenomena. The situation is quite different for
homogeneous networks where just one of these parameters, e.g. the volume
growth, is enough to determine the appearance of the condensation.


title:
Collective dynamics of water in the living cell and in bulk liquid. New
  physical models and biological inferences

abstract:
  In the frame of collective dynamics in water, models built on elementary
excitations and long-range electromagnetic interactions in the cell and bulk
liquid are presented. Making use of the low effective mass of water coherence
domains (CDs), we examined the relevance of simple quantum models to cellular
characteristics. A hypothesis of CDs Bose-type condensation, and models of CD
in spherical wells with impenetrable and semipenetrable walls, and of an
isotropic oscillator consisting of two interacting CDs were investigated.
Estimated cellular volumes matched to medium-sized bacteria and small
prokaryotes, and to some organelles in eukaryotic cells. Also, the cytotoxic
effects of heavy water in eukaryotes were explained. In another approach we
proposed a plasmon-like model of hydrogen-oxygen ionic plasma in liquid water.
In addition to plasmonic oscillations, the model predicted sound-like
non-equilibrium elementary excitations that we called densitons (the sound
anomaly of water), the vaporization heat and the permittivity dispersion, in
agreement to experimental data. The fields generated by ionic plasma
oscillations in living cells may support long distance intercellular
correlations.


title: Open strings, Lagrangian conductors and Floer functor

abstract:
  We introduce a contravariant functor, called Floer functor, from the category
of Lagrangian conductors of a symplectic manifold to the homotopy category of
bounded chain complexes of open strings in this manifold. The latter two
categories are defined for all symplectic manifolds, whereas Floer functor is
defined for semipositive manifolds which are either closed or convex at
infinity. We then prove that when the first Chern class of the symplectic
manifold vanishes, Lagrangian spheres define Lagrangian conductors so that in
particular their integral Floer cohomology is well defined. This requires the
introduction of singular almost-complex structures given by symplectic field
theory.


title: Stable ergodicity of dominated systems

abstract:
  We provide a new approach to stable ergodicity of systems with dominated
splittings, based on a geometrical analysis of global stable and unstable
manifolds of hyperbolic points. Our method suggests that the lack of uniform
size of Pesin's local stable and unstable manifolds - a notorious problem in
the theory of non-uniform hyperbolicity - is often less severe than it appeas
to be.


title: Ferrofluidity in a two-component dipolar Bose-Einstein Condensate

abstract:
  It is shown that the interface in a two-component Bose-Einstein condensate
(BEC) in which one component exhibits a dipole-dipole interaction spontaneously
forms patterns similar to those formed in a magnetic liquid subject to a
magnetic field. A hexagonal pattern, hysteretic behavior, and soliton-like
structure are numerically demonstrated. A phenomenon similar to the
labyrinthine instability is also found. These phenomena may be realized using a
52Cr BEC. The periodic density modulation in the superfluid ground state offers
evidence of supersolidity.


title:
Kernel Functions for Difference Operators of Ruijsenaars Type and Their
  Applications

abstract:
  A unified approach is given to kernel functions which intertwine Ruijsenaars
difference operators of type A and of type BC. As an application of the
trigonometric cases, new explicit formulas for Koornwinder polynomials attached
to single columns and single rows are derived.


title: High-resolution studies of the twin jet in NGC 1052

abstract:
  The radio loud galaxy NGC 1052 is being studied in an intensive multi-band
campaign including X-ray brigthness monitoring and spectroscopic observations,
single-dish radio brightness monitoring at centimetre wavelengths, and a
high-frequency very-long-baseline interferometry monitoring program. Here we
present a progress report on our studies from this program. The final goal of
our observations is to relate the findings from the high-resolution radio
images with the observed variations in the X-ray regime, to address the
accretion processes and their relationship with the radio jet activity.


title:
Radio source stacking and the infrared / radio correlation at microJy
  flux densities

abstract:
  We investigate the infrared / radio correlation using the technique of source
stacking, in order to probe the average properties of radio sources that are
too faint to be detected individually. We compare the two methods used in the
literature to stack sources, and demonstrate that the creation of stacked
images leads to a loss of information. We stack infrared sources in the Spitzer
extragalactic First Look Survey (xFLS) field, and the three northern Spitzer
Wide-area Infrared Extragalactic survey (SWIRE) fields, using radio surveys
created at 610 MHz and 1.4 GHz, and find a variation in the absolute strength
of the correlation between the xFLS and SWIRE regions, but no evidence for
significant evolution in the correlation over the 24-um flux density range 150
uJy - 2 mJy. We carry out the first radio source stacking experiment using
70-um-selected galaxies, and find no evidence for significant evolution over
the 70-um flux density range 10 mJy - 100 mJy.


title: Measurement of the shot noise in a single electron transistor

abstract:
  We have systematically measured the shot noise in a single electron
transistor (SET) as a function of bias and gate voltages. By embedding a SET in
a resonance circuit we have been able to measure its shot noise at the
resonance frequency 464 MHz, where the 1/f noise is negligible. We can extract
the Fano factor which varies between 0.5 and 1 depending on the amount of
Coulomb blockade in the SET, in very good agreement with the theory.


title: Dichotomy Results for Fixed Point Counting in Boolean Dynamical Systems

abstract:
  We present dichotomy theorems regarding the computational complexity of
counting fixed points in boolean (discrete) dynamical systems, i.e., finite
discrete dynamical systems over the domain {0,1}. For a class F of boolean
functions and a class G of graphs, an (F,G)-system is a boolean dynamical
system with local transitions functions lying in F and graphs in G. We show
that, if local transition functions are given by lookup tables, then the
following complexity classification holds: Let F be a class of boolean
functions closed under superposition and let G be a graph class closed under
taking minors. If F contains all min-functions, all max-functions, or all
self-dual and monotone functions, and G contains all planar graphs, then it is
#P-complete to compute the number of fixed points in an (F,G)-system; otherwise
it is computable in polynomial time. We also prove a dichotomy theorem for the
case that local transition functions are given by formulas (over logical
bases). This theorem has a significantly more complicated structure than the
theorem for lookup tables. A corresponding theorem for boolean circuits
coincides with the theorem for formulas.

categories: cs.CC cond-mat.dis-nn cs.DM nlin.AO nlin.CG


title:
On the linear increase of the flux tube thickness near the deconfinement
  transition

abstract:
  We study the flux tube thickness of a generic Lattice Gauge Theory near the
deconfining phase transition. It is well known that the effective string model
predicts a logarithmic increase of the flux tube thickness as a function of the
interquark distance for any confining LGT at zero temperature. It is perhaps
less known that this same model predicts a linear increase in the vicinity of
the deconfinement transition. We present a precise derivation of this result
and compare it with a set of high precision simulations in the case of the 3d
gauge Ising model.


title:
Jets, accretion, coronae and all that: The enigmatic X-rays from the
  Herbig star HD 163296

abstract:
  Herbig Ae/Be stars (HAeBe) are pre-main sequence objects in the mass range
between 2 and 8 solar masses. Their X-ray properties are uncertain and, as yet,
unexplained. We want to elucidate the X-ray generating mechanism in HAeBes. We
present a XMM-Newton observation of the HAeBe HD 163296. We analyse the light
curve, the broad band and the grating spectra, fit emission measures and
abundances and apply models for accretion and wind shocks. We find three
temperature components ranging from 0.2 keV to 2.7 keV. The O VII He-like
triplet indicates a X-ray formation region in a low density environment with a
weak UV photon field, i. e. above the stellar surface. This makes an origin in
an accretion shock unlikely, instead we suggest a shock at the base of the jet
for the soft component and a coronal origin for the hot component. A mass
outflow of 10^{-10} solar masses per year is sufficient to power the soft
X-rays. HD 163296 is thought to be single, so this data represent genuine HAeBe
X-ray emission. HD 163296 might be prototypical for its class.


title: The projective McKay correspondence

abstract:
  Kirillov has described a McKay correspondence for finite subgroups of
PSL_{2}(C) that associates to each `height' function an affine Dynkin quiver
together with a derived equivalence between equivariant sheaves on the
projective line P^1 and representations of this quiver. The equivalences for
different height functions are then related by reflection functors for quiver
representations.
  The main goal of this paper is to develop an analogous story for the
cotangent bundle of P^1. We show that each height function gives rise to a
derived equivalence between equivariant sheaves on the cotangent bundle T*P^1
and modules over the preprojective algebra of an affine Dynkin quiver. These
different equivalences are related by spherical twists, which take the place of
the reflection functors for P^1.


title: Representing geometric morphisms using power locale monads

abstract:
  It it shown that geometric morphisms between elementary toposes can be
represented as adjunctions between the corresponding categories of locales.
These adjunctions are characterised as those that preserve the order
enrichment, commute with the double power locale monad and whose right adjoints
preserve finite coproduct. They are also characterised as those adjunctions
that preserve the order enrichment and commute with both the upper and the
lower power locale monads.


title: Phase-space structures II: Hierarchical Structure Finder

abstract:
  A new multi-dimensional Hierarchical Structure Finder (HSF) to study the
phase-space structure of dark matter in N-body cosmological simulations is
presented. The algorithm depends mainly on two parameters, which control the
level of connectivity of the detected structures and their significance
compared to Poisson noise. By working in 6D phase-space, where contrasts are
much more pronounced than in 3D position space, our HSF algorithm is capable of
detecting subhaloes including their tidal tails, and can recognise other
phase-space structures such as pure streams and candidate caustics. If an
additional unbinding criterion is added, the algorithm can be used as a
self-consistent halo and subhalo finder. As a test, we apply it to a large halo
of the Millennium Simulation, where 19 % of the halo mass are found to belong
to bound substructures, which is more than what is detected with conventional
3D substructure finders, and an additional 23-36 % of the total mass belongs to
unbound HSF structures. The distribution of identified phase-space density
peaks is clearly bimodal: high peaks are dominated by the bound structures and
low peaks belong mostly to tidal streams. In order to better understand what
HSF provides, we examine the time evolution of structures, based on the merger
tree history. Bound structures typically make only up to 6 orbits inside the
main halo. Still, HSF can identify at the present time at least 80 % of the
original content of structures with a redshift of infall as high as z <= 0.3,
which illustrates the significant power of this tool to perform dynamical
analyses in phase-space.


title:
Measurement noise floor for a long-distance optical carrier transmission
  via fiber

abstract:
  We investigated the measurement floor and link stability for the transfer of
an ultra-stable optical frequency via an optical fiber link. We achieved a
near-delay-limited instability of 3x10^(-15)/(tau x Hz) for 147 km deployed
fiber, and 10^(-20) (integrations time tau = 4000 s) for the noise floor.


title:
Electrothermal feedback in superconducting nanowire single-photon
  detectors

abstract:
  We investigate the role of electrothermal feedback in the operation of
superconducting nanowire single-photon detectors (SNSPDs). It is found that the
desired mode of operation for SNSPDs is only achieved if this feedback is
unstable, which happens naturally through the slow electrical response
associated with their relatively large kinetic inductance. If this response is
sped up in an effort to increase the device count rate, the electrothermal
feedback becomes stable and results in an effect known as latching, where the
device is locked in a resistive state and can no longer detect photons. We
present a set of experiments which elucidate this effect, and a simple model
which quantitatively explains the results.


title: On the validity of nonlinear Alfven resonance in space plasmas

abstract:
  In the approximation of linear dissipative magnetohydrodynamics (MHD) it can
be shown that driven MHD waves in magnetic plasmas with high Reynolds number
exhibit a near resonant behaviour if the frequency of the wave becomes equal to
the local Alfven (or slow) frequency of a magnetic surface. This near resonant
behaviour is confined to a thin region, known as the dissipative layer, which
embraces the resonant magnetic surface. Although driven MHD waves have small
dimensionless amplitude far away from the resonant surface, this near-resonant
behaviour in the dissipative layer may cause a breakdown of linear theory. Our
aim is to study the nonlinear effects in the Alfven dissipative layer. In the
present paper, the method of simplified matched asymptotic expansions developed
for nonlinear slow resonant waves is used to describe nonlinear effects inside
the Alfven dissipative layer. The nonlinear corrections to resonant waves in
the Alfven dissipative layer are derived and it is proved that at the Alfven
resonance (with isotropic/anisotropic dissipation) wave dynamics can be
described by the linear theory with great accuracy.


title: An oscillating universe model based on chromoelectric fields

abstract:
  An oscillating universe model is discussed, in which the singularity of the
initial state of the universe is avoided by postulating an upper limit on
spacetime curvature. This also results in the devising of the simplest possible
structure - a primitive particle (usually called preon), which can be
considered as the basic constituent of matter that have no properties except
for the property of carrying a unit chromoelectric charge. The
SU(3)xU(1)-symmetry of its field results in the emergence of a unique set of
structures reproducing exactly the observed variety of the fundamental fermions
and gauge bosons. The discussed scheme allows finding answers to many
fundamental questions of the standard particle physics and cosmology based on a
very few primary constituents.


title: The Gaia Era: synergy between space missions and ground based surveys

abstract:
  The Gaia mission is expected to provide highly accurate astrometric,
photometric, and spectroscopic measurements for about $10^9$ objects. Automated
classification of detected sources is a key part of the data processing. Here a
few aspects of the Gaia classification process are presented. Information from
other surveys at longer wavelengths, and from follow-up ground based
observations will be complementary to Gaia data especially at faint magnitudes,
and will offer a great opportunity to understand our Galaxy.


title: Signatures of NP models in top FCNC decay t --> c(u) l+ l-

abstract:
  Among other roles the LHC will play a role of the top "factory" and it will
give us unique possibility to study new physics signatures in different ways.
Many scenarios of new physics allow top quark FCNC decays. Using most general
model independent Lagrangian of new physics we investigate possible
experimental signals of new physics in t --> c(u) l+ l- FCNC top decays. We
find that measurement of two possible asymmetries might give very important and
interesting information of NP. It is particularly interesting to use them to
discriminate among variety on NP scenarios. We consider also contributions of
the interference between scalar and vector mediators of the FCNC decays.


title: Quantum geometrodynamics: whence, whither?

abstract:
  Quantum geometrodynamics is canonical quantum gravity with the three-metric
as the configuration variable. Its central equation is the Wheeler--DeWitt
equation. Here I give an overview of the status of this approach. The issues
discussed include the problem of time, the relation to the covariant theory,
the semiclassical approximation as well as applications to black holes and
cosmology. I conclude that quantum geometrodynamics is still a viable approach
and provides insights into both the conceptual and technical aspects of quantum
gravity.


title: On distinguishing the direct and spontaneous CP violation in 2HDM

abstract:
  The most general Two Higgs Doublet Model (2HDM) allows both for the explicit
and the spontaneous CP violation in the scalar sector. Here we discuss CP
violation in terms of basis-independent quantities and show how using two
different sets of known CP-odd weak-basis invariants one can distinguish
between CP conservation, explicit CP violation and spontaneous CP violation.
The special case of CP violation without CP mixing, in which the neutral Higgs
gauge boson interaction respects CP while Higgs self-interaction violates CP
symmetry, is also presented.


title: New high resolution synthetic stellar libraries for the Gaia Mission

abstract:
  High resolution synthetic stellar libraries are of fundamental importance for
the preparation of the Gaia Mission. We present new sets of spectral stellar
libraries covering two spectral ranges: 300 --1100 nm at 0.1 nm resolution, and
840 -- 890 nm at 0.001 nm resolution. These libraries span a large range in
atmospheric parameters, from super-metal-rich to very metal-poor (-5.0
$<$[Fe/H]$<$+1.0), from cool to hot (\teff=3000--50000 K) stars, including
peculiar abundance variations. The spectral resolution, spectral type coverage
and number of models represent a substantial improvement over previous
libraries used in population synthesis models and in atmospheric analysis.


title: Types are weak omega-groupoids

abstract:
  We define a notion of weak omega-category internal to a model of Martin-L\"of
type theory, and prove that each type bears a canonical weak omega-category
structure obtained from the tower of iterated identity types over that type. We
show that the omega-categories arising in this way are in fact omega-groupoids.


title: Vortex invariants and toric manifolds

abstract:
  We consider the symplectic vortex equations for a linear Hamiltonian torus
action. We show that the associated genus zero moduli space itself is homotopic
(in the sense of a homotopy of regular G-moduli problems) to a toric manifold
with combinatorial data directly obtained from the original torus action. This
allows to view the wall crossing formula of Cieliebak and Salamon for the
computation of vortex invariants as a consequence of a generalized
Jeffrey-Kirwan localization formula for integrals over symplectic quotients.


title: Ion-ion correlation and charge reversal at titrating solid interfaces

abstract:
  Confronting grand canonical titration Monte Carlo simulations (MC) with
recently published titration and charge reversal (CR) experiments on silica
surfaces by Dove et al. and van der Heyden it et al, we show that ion-ion
correlations quantitatively explain why divalent counterions strongly promote
surface charge which, in turn, eventually causes a charge reversal (CR).
Titration and CR results from simulations and experiments are in excellent
agreement without any fitting parameters. This is the first unambiguous
evidence that ion-ion correlations are instrumental in the creation of highly
charged surfaces and responsible for their CR. Finally, we show that charge
correlations result in "anomalous" charge regulation in strongly coupled
conditions in qualitative desagreement with its classical treatment.


title: Optical Properties and Modal Gain of InGaN Quantum Dot Stacks

abstract:
  We present investigations of the optical properties of stacked InGaN quantum
dot layers and demonstrate their advantage over single quantum dot layer
structures. Measurements were performed on structures containing a single layer
with quantum dots or threefold stacked quantum dot layers, respectively. A
superlinear increase of the quantum dot related photoluminescence is detected
with increasing number of quantum dot layers while other relevant GaN related
spectral features are much less intensive when compared to the
photoluminescence of a single quantum dot layer. The quantum dot character of
the active material is verified by microphotoluminescence experiments at
different temperatures. For the possible integration within optical devices in
the future the threshold power density was investigated as well as the modal
gain by using the variable stripe length method.


title: High - Temperature Superconductivity in Iron Based Layered Compounds

abstract:
  We present a review of basic experimental facts on the new class of high -
temperature superconductors - iron based layered compounds like REOFeAs
(RE=La,Ce,Nd,Pr,Sm...), AFe_2As_2 (A=Ba,Sr...), AFeAs (A=Li,...) and FeSe(Te).
We discuss electronic structure, including the role of correlations, spectrum
and role of collective excitations (phonons, spin waves), as well as the main
models, describing possible types of magnetic ordering and Cooper pairing in
these compounds.


title: End-to-end entanglement in Bose-Hubbard chains

abstract:
  We study the ground state as well as the dynamics of chains of bosons with
local repulsive interactions and nearest-neighbour exchange using numerical
techniques based on density matrix decimation. We explore the development of
entanglement between the terminal sites of such chains as mechanisms are
invoked to concentrate population in these sites. We find that long-range
entanglement in the ground state emerges as a result of hopping taking place at
the whole chain length in systems with appropriate hopping coefficients.
Additionally, we find appropriate perturbations to increase the entanglement
between the end sites above their ground state values.


title:
Introducing a Hybrid Method of Radiative Transfer for Smoothed Particle
  Hydrodynamics

abstract:
  A new means of incorporating radiative transfer into smoothed particle
hydrodynamics (SPH) is introduced, which builds on the success of two previous
methods - the polytropic cooling approximation as devised by Stamatellos et al
(2007), and flux limited diffusion (e.g. Mayer et al 2007). This hybrid method
preserves the strengths of its individual components, while removing the need
for atmosphere matching or other boundary conditions to marry optically thick
and optically thin regions. The code uses a non-trivial equation of state to
calculate temperatures and opacities of SPH particles, which captures the
effects of molecular hydrogen dissociation, atomic hydrogen ionisation, He0 and
He+ ionisation, ice evaporation, dust sublimation, molecular absorption,
bound-free and free-free transitions and electron scattering. The method is
tested in several scenarios, including: (1) the evolution of a 0.07 solar mass
protoplanetary disc surrounding a 0.5 solar mass star; (2) the collapse of a 1
solar mass protostellar cloud, and (3) the thermal relaxation of temperature
fluctuations in a static homogeneous sphere.


title:
Collisionless Magnetic Reconnection in a Five-Moment Two-Fluid
  Electron-Positron Plasma

abstract:
  We simulate magnetic reconnection in electron-positron (pair) plasma using a
collisionless two-fluid model with isotropic pressure. In this model the
resistive, Hall, and electrokinetic pressure terms are absent from the curl of
Ohm's law, leaving the inertial term alone to provide for magnetic
reconnection. Our simulations suggest that for pair plasma simulated with
isotropic pressure fast reconnection does not occur without the aid of
sufficient (numerical) diffusion. We contrast this result with simulations and
published results showing fast reconnection for collisionless two-fluid plasma
with isotropic pressures and non-canceling mass-to-charge ratios, where Hall
effects are present and numerical diffusion is small, and with published PIC
studies of pair plasma which observe fast reconnection and attribute it to
nonisotropic pressure.


title:
Neutrino signal from gamma-ray loud binaries powered by high energy
  protons

abstract:
  We present a hadronic model of activity for Galactic gamma-ray-loud binaries,
in which the multi-TeV neutrino flux from the source can be much higher and/or
harder than the detected TeV gamma-ray flux. This is related to the fact that
most neutrinos are produced in pp interactions close to the bright massive
star, in a region optically thick for the TeV gamma-rays. Considering the
specific example of LS I +61o 303, we derive upper bounds for neutrino fluxes
from various proton injection spectra compatible with the observed
multi-wavelength spectrum. At this upper level of neutrino emission, we
demonstrate that ICECUBE will not only detect this source at 5 sigma C.L. after
one year of operation, but, after 3 years of exposure, will also collect a
sample marginally sufficient to constrain the spectral characteristics of the
neutrino signal, directly related to the underlying source acceleration
mechanisms.


title: Color Octet Scalar Bound States at the LHC

abstract:
  One possible extension of the Standard Model scalar sector includes SU(2)_L
doublet scalars that are color octets rather than singlets. We focus on models
in which the couplings to fermions are consistent with the principle of minimal
flavor violation (MFV), in which case these color octet scalars couple most
strongly to the third generation of quarks. When the Yukawa coupling of color
octet scalars to Standard Model fermions is less than unity, these states can
live long enough to bind into color-singlet spin-0 hadrons, which we call
octetonia. In this paper, we consider the phenomenology of octetonia at the
Large Hadron Collider (LHC). Predictions for their production via gluon-gluon
fusion and their two-body decays into Standard Model gauge bosons, Higgs
bosons, and \bar{t}t are presented.


title: Dark matter and sub-GeV hidden U(1) in GMSB models

abstract:
  Motivated by the recent PAMELA and ATIC data, one is led to a scenario with
heavy vector-like dark matter in association with a hidden $U(1)_X$ sector
below GeV scale. Realizing this idea in the context of gauge mediated
supersymmetry breaking (GMSB), a heavy scalar component charged under $U(1)_X$
is found to be a good dark matter candidate which can be searched for direct
scattering mediated by the Higgs boson and/or by the hidden gauge boson. The
latter turns out to put a stringent bound on the kinetic mixing parameter
between $U(1)_X$ and $U(1)_Y$: $\theta \lesssim 10^{-6}$. For the typical range
of model parameters, we find that the decay rates of the ordinary lightest
neutralino into hidden gauge boson/gaugino and photon/gravitino are comparable,
and the former decay mode leaves displaced vertices of lepton pairs and missing
energy with distinctive length scale larger than 20 cm for invariant lepton
pair mass below 0.5 GeV. An unsatisfactory aspect of our model is that the
Sommerfeld effect cannot raise the galactic dark matter annihilation by more
than 60 times for the dark matter mass below TeV.


title:
Vibrational nonequilibrium effects in the conductance of
  single-molecules with multiple electronic states

abstract:
  Vibrational nonequilibrium effects in charge transport through
single-molecule junctions are investigated. Focusing on molecular bridges with
multiple electronic states, it is shown that electronic-vibrational coupling
triggers a variety of vibronic emission and absorption processes, which
influence the conductance properties and mechanical stability of
single-molecule junctions profoundly. Employing a master equation and a
nonequilibrium Green's function approach, these processes are analyzed in
detail for a generic model of a molecular junction and for
benzenedibutanethiolate bound to gold electrodes.


title: Spectropolarimetric Variability and Co-Rotating Structure in HD 92207

abstract:
  We report on low resolution (R~3000) spectropolarimetry of the A0 supergiant
star HD 92207. This star is well-known for significant spectral variability.
The source was observed on seven different nights spanning approximately 3
months in time. With a rotation period of approximately 1 year, our data covers
approximately a quarter of the star's rotational phase. Variability in the
continuum polarization level is observed over this period of time. The
polarization across the Halpha line on any given night is typically different
from the degree and position angle of the polarization in the continuum.
Interestingly, Hbeta is not in emission and does not show polarimetric
variability. We associate the changes at Halpha as arising in the wind, which
is in accord with the observed changes in the profile shape and equivalent
width of Halpha along with the polarimetric variability. For the continuum
polarization, we explore a spiral shaped wind density enhancement in the
equatorial plane of the star, in keeping with the suggestion of Kaufer etal
(1997). Variable polarization signatures across Halpha are too complex to be
explained by this simple model and will require a more intensive polarimetric
follow-up study to interpret properly.


title: Multi-wavelength observations and modelling of a canonical solar flare

abstract:
  This paper investigates the temporal evolution of temperature, emission
measure, energy loss and velocity in a C-class solar flare from both an
observational and theoretical perspective. The properties of the flare were
derived by following the systematic cooling of the plasma through the response
functions of a number of instruments -- RHESSI (>5 MK), GOES-12 (5-30 MK),
TRACE 171 A (1 MK) and SOHO/CDS (~0.03-8 MK). These measurements were studied
in combination with simulations from the 0-D EBTEL model. At the flare on-set,
upflows of ~90 km s-1 and low level emission were observed in Fe XIX,
consistent with pre-flare heating and gentle chromospheric evaporation. During
the impulsive phase, upflows of ~80 km s-1 in Fe XIX and simultaneous downflows
of 20 km s-1 in He I and O V were observed, indicating explosive chromospheric
evaporation. The plasma was subsequently found to reach a peak temperature of
~13 MK in approximately 10 minutes. Using EBTEL, conduction was found to be the
dominant loss mechanism during the initial ~300s of the decay phase. It was
also found to be responsible for driving gentle chromospheric evaporation
during this period. As the temperature fell below ~8 MK, and for the next
~4,000s, radiative losses were determined to dominate over conductive losses.
The radiative loss phase was accompanied by significant downflows of <40 km s-1
in O V. This is the first extensive study of the evolution of a canonical solar
flare using both spectroscopic and broad-band instruments in conjunction with a
hydrodynamic model. While our results are in broad agreement with the standard
flare model, the simulations suggest that both conductive and non-thermal beam
heating play important roles in heating the flare plasma during the impulsive
phase of at least this event.


title: Holomorphic factorization of mappings into SL_n(C)

abstract:
  We solve Gromov's Vaserstein problem. Namely, we show that a null-homotopic
holomorphic mapping from a finite dimensional reduced Stein space into SL_n(C)
can be factored into a finite product of unipotent matrices with holomorphic
entries.


title: Splitting Monoidal Stable Model Categories

abstract:
  If C is a stable model category with a monoidal product then the set of
homotopy classes of self-maps of the unit S forms a commutative ring. An
idempotent e of this ring will split the homotopy category. We prove that
provided the localised model structures exist, this splitting of the homotopy
category comes from a splitting of the model category, that is, C is Quillen
equivalent to the product of C localised at the object eS and C localised at
the object (1-e)S. This Quillen equivalence is strong monoidal and is symmetric
when the monoidal product of C is.


title: Higher Bers maps

abstract:
  The Bers embebbing realizes the Teichm\"uller space of a Fuchsian group $G$
as a open, bounded and contractible subset of the complex Banach space of
bounded quadratic differentials for $G$. It utilizes the schlicht model of
Teichm\"uller space, where each point is represented by an injective
holomorphic function on the disc, and the map is constructed via the Schwarzian
differential operator.
  In this paper we prove that a certain class of differential operators acting
on functions of the disc induce holomorphic mappings of Teichm\"uller spaces,
and we also obtain a general formula for the differential of the induced
mappings at the origin. The main focus of this work, however, is on two
particular series of such mappings, dubbed higher Bers maps, because they are
induced by so-called higher Schwarzians -- generalizations of the classical
Schwarzian operator. For these maps, we prove several further results.
  The last section contains a discussion of possible applications, open
questions and speculations.


title: Masses and widths of scalar tetraquarks with hidden bottom

abstract:
  The relativistic four-quark equations are found in the framework of
coupled-channel formalism. The dynamical mixing of the meson-meson states with
the four-quark states is considered. The four-quark amplitudes of the
tetraquarks with hidden bottom, including u, d, s and bottom quarks, are
constructed. The poles of these amplitudes determine the masses and widths of
tetraquarks.


title: A graph theoretical analysis of the energy landscape of model polymers

abstract:
  In systems characterized by a rough potential energy landscape, local
energetic minima and saddles define a network of metastable states whose
topology strongly influences the dynamics. Changes in temperature, causing the
merging and splitting of metastable states, have non trivial effects on such
networks and must be taken into account. We do this by means of a recently
proposed renormalization procedure. This method is applied to analyze the
topology of the network of metastable states for different polypeptidic
sequences in a minimalistic polymer model. A smaller spectral dimension emerges
as a hallmark of stability of the global energy minimum and highlights a
non-obvious link between dynamic and thermodynamic properties.


title: Classifying Rational G-Spectra for Finite G

abstract:
  We give a new proof that for a finite group G, the category of rational
G-equivariant spectra is Quillen equivalent to the product of the model
categories of chain complexes of modules over the rational group ring of the
Weyl group of H in G, as H runs over the conjugacy classes of subgroups of G.
Furthermore the Quillen equivalences of our proof are all symmetric monoidal.
Thus we can understand categories of algebras or modules over a ring spectrum
in terms of the algebraic model.


title: Clues from the prompt emission of GRB 080319B

abstract:
  The extremely bright optical flash that accompanied GRB 080319B suggested, at
first glance, that the prompt $\gamma$-rays in this burst were produced by
Synchrotron self Compton (SSC). We analyze here the observed optical and
$\gamma$ spectrum. We find that the very strong optical emission poses, due to
self absorption, very strong constraints on the emission processes and put the
origin of the optical emission at a very large radius, almost inconsistent with
internal shock. Alternatively it requires a very large random Lorentz factor
for the electrons. We find that SSC could not have produced the prompt
$\gamma$-rays. We also show that the optical emission and the $\gamma$ rays
could not have been produced by synchrotron emission from two populations of
electron within the same emitting region. Thus we must conclude that the
optical and the $\gamma$-rays were produced in different physical regions. A
possible interpretation of the observations is that the $\gamma$-rays arose
from internal shocks but the optical flash resulted from external shock
emission. This would have been consistent with the few seconds delay observed
between the optical and $\gamma$-rays signals.


title: Secrecy Capacity of a Class of Broadcast Channels with an Eavesdropper

abstract:
  We study the security of communication between a single transmitter and
multiple receivers in a broadcast channel in the presence of an eavesdropper.
We consider several special classes of channels. As the first model, we
consider the degraded multi-receiver wiretap channel where the legitimate
receivers exhibit a degradedness order while the eavesdropper is more noisy
with respect to all legitimate receivers. We establish the secrecy capacity
region of this channel model. Secondly, we consider the parallel multi-receiver
wiretap channel with a less noisiness order in each sub-channel, where this
order is not necessarily the same for all sub-channels. We establish the common
message secrecy capacity and sum secrecy capacity of this channel. Thirdly, we
study a special class of degraded parallel multi-receiver wiretap channels and
provide a stronger result. In particular, we study the case with two
sub-channels two users and one eavesdropper, where there is a degradedness
order in each sub-channel such that in the first (resp. second) sub-channel the
second (resp. first) receiver is degraded with respect to the first (resp.
second) receiver, while the eavesdropper is degraded with respect to both
legitimate receivers in both sub-channels. We determine the secrecy capacity
region of this channel. Finally, we focus on a variant of this previous channel
model where the transmitter can use only one of the sub-channels at any time.
We characterize the secrecy capacity region of this channel as well.


title: Stackelberg Network Pricing is Hard to Approximate

abstract:
  In the Stackelberg Network Pricing problem, one has to assign tariffs to a
certain subset of the arcs of a given transportation network. The aim is to
maximize the amount paid by the user of the network, knowing that the user will
take a shortest st-path once the tariffs are fixed. Roch, Savard, and Marcotte
(Networks, Vol. 46(1), 57-67, 2005) proved that this problem is NP-hard, and
gave an O(log m)-approximation algorithm, where m denote the number of arcs to
be priced. In this note, we show that the problem is also APX-hard.


title:
Large-N scaling behavior of the ground-state energy and fidelity in the
  Dicke Model

abstract:
  Within the numerically exact solution to the Dicke model proposed previously,
we study the quantum criticality in terms of the ground-state (GS) energy,
fidelity, and the order parameter. The finite size scaling analysis for the
average fidelity susceptibility (FS) and second derivative of GS energy are
performed. The correlation length exponent is obtained to be $\nu=2/3$, which
is the same as that in Lipkin-Meshkov-Glick model obtained previously,
suggesting the same universality. It is observed that average FS and second
derivative of GS energy show similar critical behavior, demonstrating the
intrinsic relation in the Dicke model. The scaling behavior for the order
parameter and the singular part of the GS energy at the critical point are also
analyzed and the obtained exponents are consistent with the previous scaling
hypothesis in 1/N expansion scheme.


title:
Energy Spectra of Elemental Groups of Cosmic Rays: Update on the KASCADE
  Unfolding Analysis

abstract:
  The KASCADE experiment measures extensive air showers induced by cosmic rays
in the energy range around the so-called knee. The data of KASCADE have been
used in a composition analysis showing the knee at 3-5 PeV to be caused by a
steepening in the light-element spectra. Since the applied unfolding analysis
depends crucially on simulations of air showers, different high energy hadronic
interaction models (QGSJet and SIBYLL) were used. The results have shown a
strong dependence of the relative abundance of the individual mass groups on
the underlying model. In this update of the analysis we apply the unfolding
method with a different low energy interaction model (FLUKA instead of GHEISHA)
in the simulations. While the resulting individual mass group spectra do not
change significantly, the overall description of the measured data improves by
using the FLUKA model. In addition data in a larger range of zenith angle are
analysed. The new results are completely consistent, i.e. there is no hint to
any severe problem in applying the unfolding analysis method to KASCADE data.


title: Pion form factor from local-duality QCD sum rule

abstract:
  We present our recent results for the pion elastic form factor [1] obtained
within a local-duality three-point sum rule (a Borel sum rule in the limit of
an infinite Borel parameter). Our analysis includes the O(1) and O(\alpha_s)
contributions and is therefore applicable in a broad range of spacelike
momentum transfers. Our results demonstrate in essentially model-independent
way that the O(1) term, which provides the subleading 1/Q^4 power correction at
asymptotically large momentum transfers, contributes more than half of the pion
form factor in the region Q^2 \le 20 GeV^2. To probe the accuracy of
local-duality sum rules for form factors, we apply precisely the same
procedures to extract the form factor in a quantum-mechanical potential model.
Comparison of the exact form factor known in this model with the result of the
sum-rule calculation gives a probe of the systematic error of the method. In
our example this error is found to be at the level of 10-20%. We expect similar
systematic errors for form factors obtained from local-duality sum rules in
QCD.


title: Random matrix analysis of the QCD sign problem for general topology

abstract:
  Motivated by the important role played by the phase of the fermion
determinant in the investigation of the sign problem in lattice QCD at nonzero
baryon density, we derive an analytical formula for the average phase factor of
the fermion determinant for general topology in the microscopic limit of chiral
random matrix theory at nonzero chemical potential, for both the quenched and
the unquenched case. The formula is a nontrivial extension of the expression
for zero topology derived earlier by Splittorff and Verbaarschot. Our
analytical predictions are verified by detailed numerical random matrix
simulations of the quenched theory.


title:
Ageing as a price of cooperation and complexity: Self-organization of
  complex systems causes the ageing of constituent networks

abstract:
  The network concept is increasingly used for the description of complex
systems. Here we summarize key aspects of the evolvability and robustness of
the hierarchical network-set of macromolecules, cells, organisms, and
ecosystems. Listing the costs and benefits of cooperation as a necessary
behaviour to build this network hierarchy, we outline the major hypothesis of
the paper: the emergence of hierarchical complexity needs cooperation leading
to the ageing (i.e. gradual deterioration) of the constituent networks. A
stable environment develops cooperation leading to over-optimization, and
forming an "always-old" network, which accumulates damage, and dies in an
apoptosis-like process. A rapidly changing environment develops competition
forming a "forever-young" network, which may suffer an occasional
over-perturbation exhausting system-resources, and causing death in a
necrosis-like process. Giving a number of examples we demonstrate how
cooperation evokes the gradual accumulation of damage typical to ageing.
Finally, we show how various forms of cooperation and consequent ageing emerge
as key elements in all major steps of evolution from the formation of
protocells to the establishment of the globalized, modern human society.


title:
Giants in the globular cluster omega Centauri: dust production, mass
  loss and distance

abstract:
  We present spectral energy distribution modelling of 6875 stars in omega
Centauri, obtaining stellar luminosities and temperatures by fitting literature
photometry to state-of-the-art MARCS stellar models. By comparison to four
different sets of isochrones, we provide a new distance estimate to the cluster
of 4850 +/- 200 (random) +/- 120 (systematic error) pc, a reddening of E(B-V) =
0.08 +/- 0.02 +/- 0.02 mag and a differential reddening of Delta[E(B-V)] < 0.02
mag for an age of 12 Gyr. Several new post-early-AGB candidates are also found.
Infra-red excesses of stars were used to measure total mass-loss rates for
individual stars down to ~7 x 10^-8 Msun/yr. We find a total dust mass-loss
rate from the cluster of 1.3 (+0.8/-0.5) x 10^-9 Msun/yr, with the total gas
mass-loss rate being > 1.2 (+0.6/-0.5) x 10^-6 Msun/yr. Half of the cluster's
dust production and 30% of its gas production comes from the two most extreme
stars - V6 and V42 - for which we present new Gemini/T-ReCS mid-infrared
spectroscopy, possibly showing that V42 has carbon-rich dust. The cluster's
dust temperatures are found to be typically >~550 K. Mass loss apparently does
not vary significantly with metallicity within the cluster, but shows some
correlation with barium enhancement, which appears to occur in cooler stars,
and especially on the anomalous RGB. Limits to outflow velocities, dust-to-gas
ratios for the dusty objects and the possibility of short-timescale mass-loss
variability are also discussed in the context of mass loss from low-metallicity
stars. The ubiquity of dust around stars near the RGB-tip suggests significant
dusty mass loss on the RGB; we estimate that typically 0.20--0.25 Msun of mass
loss occurs on the RGB. From observational limits on intra-cluster material, we
suggest the dust is being cleared on a timescale of <~10^5 years.


title:
Determining the unsaturated hydraulic conductivity of a compacted
  sand-bentonite mixture under constant volume and free-swell conditions

abstract:
  Highly compacted sand-bentonite mixtures are often considered as possible
engineered barriers in deep high-level radioactive waste disposals. In-situ,
the saturation of these barriers from their initially unsaturated state is a
complex hydro-mechanical coupled process in which temperature effects also play
a role. The key parameter of this process is the unsaturated hydraulic
conductivity of the barrier. In this paper, isothermal infiltration experiments
were conducted to determine the unsaturated hydraulic conductivity according to
the instantaneous profile method. To do so, total suction changes were
monitored at different locations along the soil specimen by using resistivity
relative humidity probes. Three constant volume infiltration tests were
conducted showing, unexpectedly, a decrease of the hydraulic conductivity
during infiltration. One test performed under free-swell conditions showed the
opposite and standard trend. These observations were interpreted in terms of
microstructure changes during wetting, both under constant volume and free
swell conditions.


title:
On electrostatic and Casimir force measurements between conducting
  surfaces in a sphere-plane configuration

abstract:
  We report on measurements of forces acting between two conducting surfaces in
a spherical-plane configuration in the 35 nm-1 micrometer separation range. The
measurements are obtained by performing electrostatic calibrations followed by
a residual analysis after subtracting the electrostatic-dependent component. We
find in all runs optimal fitting of the calibrations for exponents smaller than
the one predicted by electrostatics for an ideal sphere-plane geometry. We also
find that the external bias potential necessary to minimize the electrostatic
contribution depends on the sphere-plane distance. In spite of these anomalies,
by implementing a parametrixation-dependent subtraction of the electrostatic
contribution we have found evidence for short-distance attractive forces of
magnitude comparable to the expected Casimir-Lifshitz force. We finally discuss
the relevance of our findings in the more general context of Casimir-Lifshitz
force measurements, with particular regard to the critical issues of the
electrical and geometrical characterization of the involved surfaces.


title: Block-Sparsity: Coherence and Efficient Recovery

abstract:
  We consider compressed sensing of block-sparse signals, i.e., sparse signals
that have nonzero coefficients occuring in clusters. Based on an uncertainty
relation for block-sparse signals, we define a block-coherence measure and we
show that a block-version of the orthogonal matching pursuit algorithm recovers
block k-sparse signals in no more than k steps if the block-coherence is
sufficiently small. The same condition on block-sparsity is shown to guarantee
successful recovery through a mixed l2/l1 optimization approach. The
significance of the results lies in the fact that making explicit use of
block-sparsity can yield better reconstruction properties than treating the
signal as being sparse in the conventional sense thereby ignoring the
additional structure in the problem.


title:
Polynomial parametrization of the solutions of Diophantine equations of
  genus 0

abstract:
  Let f in Z[X,Y,Z] be a non-constant, absolutely irreducible, homogeneous
polynomial with integer coefficients, such that the projective curve given by
f=0 has a function field isomorphic to the rational function field Q(t). We
show that all integral solutions of the Diophantine equation f=0 (up to those
corresponding to some singular points) can be parametrized by a single triple
of integer-valued polynomials. In general, it is not possible to parametrize
this set of solutions by a single triple of polynomials with integer
coefficients.


title:
Coarse-grained models for fluids and their mixtures: Comparison of Monte
  Carlo studies of their phase behavior with perturbation theory and experiment

abstract:
  The prediction of the equation of state and the phase behavior of simple
fluids (noble gases, carbon dioxide, benzene, methane, short alkane chains) and
their mixtures by Monte Carlo computer simulation and analytic approximations
based on thermodynamic perturbation theory is discussed. Molecules are
described by coarse grained (CG) models, where either the whole molecule
(carbon dioxide, benzene, methane) or a group of a few successive CH_2 groups
(in the case of alkanes) are lumped into an effective point particle.
Interactions among these point particles are fitted by Lennard-Jones (LJ)
potentials such that the vapor-liquid critical point of the fluid is reproduced
in agreement with experiment; in the case of quadrupolar molecules a
quadrupole-quadrupole interaction is included. These models are shown to
provide a satisfactory description of the liquid-vapour phase diagram of these
pure fluids. Investigations of mixtures, using the Lorentz-Berthelot (LB)
combining rule, also produce satisfactory results if compared with experiment,
while in some previous attempts (in which polar solvents were modelled without
explicitly taking into account quadrupolar interaction), strong violations of
the LB rules were required. For this reason, the present investigation is a
step towards predictive modelling of polar mixtures at low computational cost.
These very simple coarse-grained models of small molecules developed here
should be useful e.g. for simulations of polymer solutions with such molecules
as solvent.


title: Fermionic Spectrum on General Dimensional Hyperdiamond Lattice

abstract: Withdrawn: replaced by e-Print: arXiv:0907.3774