title:
Morphological changes of a superconducting phase in a mixed state with a
  normal current: a multiple scale analysis

abstract:
  The mixed state of superconducting (SC) and normal (N) phases in one
dimensional systems are characterized by several phase slips and localization
of the order parameter of the SC phase. The phenomenon is explained on the
basis of a complex Ginzburg Landau (CGL) model. We present a simple analysis of
the system on multiple scales to capture localization and phase slips when
phases coexist.


title:
Determination of the Newtonian Gravitational Constant Using Atom
  Interferometry

abstract:
  We present a new measurement of the Newtonian gravitational constant G based
on cold atom interferometry. Freely falling samples of laser-cooled rubidium
atoms are used in a gravity gradiometer to probe the field generated by nearby
source masses. In addition to its potential sensitivity, this method is
intriguing as gravity is explored by a quantum system. We report a value of
G=6.667 10^{-11} m^{3} kg^{-1} s^{-2}, estimating a statistical uncertainty of
$\pm$ 0.011 10^{-11} m^{3} kg^{-1} s^{-2} and a systematic uncertainty of $\pm$
0.003 10^{-11} m^{3} kg^{-1} s^{-2}. The long-term stability of the instrument
and the signal-to-noise ratio demonstrated here open interesting perspectives
for pushing the measurement accuracy below the 100 ppm level.


title: Homological properties of cochain Differential Graded algebras

abstract:
  Consider a local chain Differential Graded algebra, such as the singular
chain complex of a pathwise connected topological group.
  In two previous papers, a number of homological results were proved for such
an algebra: An Amplitude Inequality, an Auslander-Buchsbaum Equality, and a Gap
Theorem. These were inspired by homological ring theory.
  By the so-called looking glass principle, one would expect that analogous
results exist for simply connected cochain Differential Graded algebras, such
as the singular cochain complex of a simply connected topological space.
  Indeed, this paper establishes such analogous results.


title: Simulating Black Hole White Dwarf Encounters

abstract:
  The existence of supermassive black holes lurking in the centers of galaxies
and of stellar binary systems containing a black hole with a few solar masses
has been established beyond reasonable doubt. The idea that black holes of
intermediate masses ($\sim 1000$ \msun) may exist in globular star clusters has
gained credence over recent years but no conclusive evidence has been
established yet. An attractive feature of this hypothesis is the potential to
not only disrupt solar-type stars but also compact white dwarf stars. In close
encounters the white dwarfs can be sufficiently compressed to thermonuclearly
explode. The detection of an underluminous thermonuclear explosion accompanied
by a soft, transient X-ray signal would be compelling evidence for the presence
of intermediate mass black holes in stellar clusters. In this paper we focus on
the numerical techniques used to simulate the entire disruption process from
the initial parabolic orbit, over the nuclear energy release during tidal
compression, the subsequent ejection of freshly synthesized material and the
formation process of an accretion disk around the black hole.


title:
Order parameter configurations in the Lifshitz-type incommensurate
  ferroelectric thin films

abstract:
  The Dzialoshinskii model of periodic and helicoidal structures has been
analyzed without neglecting of the amplitude function oscillations. The
amplitude function oscillations are shown to be important for understanding of
the nature of the phase function. Analytic consideration is carried out in the
limit of small anisotropy (neglecting the cosine term in the Hamiltonian).
Surprisingly, the phase jumps survive even in the limit of the vanishing
anisotropy.


title: Note on a Conjecture of Wegner

abstract:
  The optimal packings of n unit discs in the plane are known for those natural
numbers n, which satisfy certain number theoretic conditions. Their geometric
realizations are the extremal Groemer packings (or Wegner packings). But an
extremal Groemer packing of n unit discs does not exist for all natural numbers
n and in this case, the number n is called exceptional. We are interested in
number theoretic characterizations of the exceptional numbers. A counterexample
is given to a conjecture of Wegner concerning such a characterization. We
further give a characterization of the exceptional numbers, whose shape is
closely related to that of Wegner's conjecture.


title: The Master Space of N=1 Gauge Theories

abstract:
  The full moduli space M of a class of N=1 supersymmetric gauge theories is
studied. For gauge theories living on a stack of D3-branes at Calabi-Yau
singularities X, M is a combination of the mesonic and baryonic branches, the
former being the symmetric product of X. In consonance with the mathematical
literature, the single brane moduli space is called the master space F.
Illustrating with a host of explicit examples, we exhibit many
algebro-geometric properties of the master space such as when F is toric
Calabi-Yau, behaviour of its Hilbert series, its irreducible components and its
symmetries. In conjunction with the plethystic programme, we investigate the
counting of BPS gauge invariants, baryonic and mesonic, using the geometry of F
and show how its refined Hilbert series not only engenders the generating
functions for the counting but also beautifully encode ``hidden'' global
symmetries of the gauge theory which manifest themselves as symmetries of the
complete moduli space M for arbitrary number of branes.


title: On the metric character of the quantum Jensen-Shannon divergence

abstract:
  In a recent paper, the generalization of the Jensen Shannon divergence (JSD)
in the context of quantum theory has been studied (Phys. Rev. A 72, 052310
(2005)). This distance between quantum states has shown to verify several of
the properties required for a good distinguishability measure. Here we
investigate the metric character of this distance. More precisely we show,
formally for pure states and by means of simulations for mixed states, that its
square root verifies the triangle inequality.


title:
On why the Iron K-shell absorption in AGN is not a signature of the
  local Warm/Hot Intergalactic Medium

abstract:
  We present a comparison between the 2001 XMM-Newton and 2005 Suzaku
observations of the quasar, PG1211+143 at z=0.0809. Variability is observed in
the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which
is significantly weaker in 2005 than during the 2001 XMM-Newton observation.
From a recombination timescale of <4 years, this implies an absorber density
n>0.004 particles/cm3, while the absorber column is 5e22<N_H <1 1e24
particles/cm2. Thus the sizescale of the absorber is too compact (pc scale) and
the surface brightness of the dense gas too high (by 9-10 orders of magnitude)
to arise from local hot gas, such as the local bubble, group or Warm/Hot
Intergalactic Medium (WHIM), as suggested by McKernan et al. (2004, 2005).
Instead the iron K-shell absorption must be associated with an AGN outflow with
mildly relativistic velocities. Finally we show that the the association of the
absorption in PG1211+143 with local hot gas is simply a coincidence, the
comparison between the recession and iron K absorber outflow velocities in
other AGN does not reveal a one to one kinematic correlation.


title:
Robust control of quantized motional states of a chain of trapped ions
  by collective adiabatic passage

abstract:
  A simple technique for robust generation of vibrational Fock states in a
chain of trapped ions is proposed. The method is fast and easy to implement,
since only a single chirped laser pulse, simultaneously addressing all of the
ions, is required. Furthermore, because the approach uses collective adiabatic
passage, significant fluctuations in the intensity or frequency of the laser
pulse can be tolerated, and the technique performs well even on the border of
the Lamb-Dicke regime. We also demonstrate how this technique may be extended
in order to create non-classical superposition states of the ions' collective
motion and Greenberger-Horne-Zeilinger states of their internal states. Because
only a single laser pulse is required, heating effects arising under realistic
experimental conditions are negligibly small.


title:
Reduction theory for mapping class groups and applications to moduli
  spaces

abstract:
  Let $S=S_{g,p}$ be a compact, orientable surface of genus $g$ with $p$
punctures and such that $d(S):=3g-3+p>0$. The mapping class group
$\textup{Mod}_S$ acts properly discontinuously on the Teichm\"uller space
$\mathcal T(S)$ of marked hyperbolic structures on $S$. The resulting quotient
$\mathcal M(S)$ is the moduli space of isometry classes of hyperbolic surfaces.
We provide a version of precise reduction theory for finite index subgroups of
$\textup{Mod}_S$, i.e., a description of exact fundamental domains. As an
application we show that the asymptotic cone of the moduli space $\mathcal
M(S)$ endowed with the Teichm\"uller metric is bi-Lipschitz equivalent to the
Euclidean cone over the finite simplicial (orbi-) complex $
\textup{Mod}_S\backslash\mathcal C(S)$, where $\mathcal C(S)$ of $S$ is the
complex of curves of $S$. We also show that if $d(S)\geq 2$, then $\mathcal
M(S)$ does \emph{not} admit a finite volume Riemannian metric of (uniformly
bounded) positive scalar curvature in the bi-Lipschitz class of the
Teichm\"uller metric. These two applications confirm conjectures of Farb.


title: Fermi, Pasta, Ulam and a mysterious lady

abstract:
  It is reported that the numerical simulations of the Fermi-Pasta-Ulam problem
were performed by a young lady, Mary Tsingou. After 50 years of omission, it is
time for a proper recognition of her decisive contribution to the first ever
numerical experiment, central in the solitons and chaos theories, but also one
of the very first out-of-equilibrium statistical mechanics study. Let us quote
from now on the Fermi-Pasta-Ulam-Tsingou problem.

categories: physics.hist-ph cond-mat.stat-mech nlin.CD nlin.PS nlin.SI


title:
Generating function identities for $\zeta(2n+2), \zeta(2n+3)$ via the WZ
  method

abstract:
  Using the WZ method we present simpler proofs of Koecher's, Leshchiner's and
Bailey-Borwein-Bradley's identities for generating functions of the sequences
$\{\zeta(2n+2)\}_{n\ge 0}, \{\zeta(2n+3)\}_{n\ge 0}.$ By the same method we
give several new representations for these generating functions yielding faster
convergent series for values of the Riemann zeta function.


title:
$2\gamma$ and $3\gamma$ annihilation as calibration processes for high
  energy $e^+ e^-$ colliders

abstract:
  Born differential cross sections and the lowest-order radiative correction to
them are obtained in the kinematics of large-angle final photons emission in
high-energy electron-positron annihilation processes. Taking into account
possible emission of real soft and hard photons in collinear kinematics we show
the validity of the Drell-Yan form of differential cross section with the
nonsinglet structure functions of initial leptons. The leading and next-to
leading contribution to the cross sections is obtained. The relevant numerical
estimations are presented.


title:
Evaluation of the semiclassical coherent state propagator in the
  presence of phase space caustics

abstract:
  A uniform approximation for the coherent state propagator, valid in the
vicinity of phase space caustics, was recently obtained using the Maslov method
combined with a dual representation for coherent states. In this paper we
review the derivation of this formula and apply it to two model systems: the
one-dimensional quartic oscillator and a two-dimensional chaotic system.


title: The Evolution of Stellar Mass and the Implied Star Formation History

abstract:
  We present a compilation of measurements of the stellar mass density as a
function of redshift. Using this stellar mass history we obtain a star
formation history and compare it to the instantaneous star formation history.
For z<0.7 there is good agreement between the two star formation histories. At
higher redshifts the instantaneous indicators suggest star formation rates
larger than that implied by the evolution of the stellar mass density. This
discrepancy peaks at z=3 where instantaneous indicators suggest a star
formation rate around 0.6 dex higher than those of the best fit to the stellar
mass history. We discuss a variety of explanations for this inconsistency, such
as inaccurate dust extinction corrections, incorrect measurements of stellar
masses and a possible evolution of the stellar initial mass function.


title: Entangling single photons on a beamsplitter

abstract:
  We report on a scheme for the creation of time-bin entangled states out of
two subsequent single photons. Both photons arrive on the same input port of a
beamsplitter and the situation in which the photons leave the beamsplitter on
different output ports is post-selected. We derive a full quantum mechanical
analysis of such time-bin entanglement for emitters subject to uncorrelated
dephasing processes and apply this model to sequential single photons emerging
from a single semiconductor quantum dot. Our results indicate that the
visibility of entanglement is degraded by decoherence effects in the quantum
dot, but can be restored by use of CQED effects, namely the Purcell effect.


title:
Transport Length Scales in Disordered Graphene-based Materials: Strong
  Localization Regimes and Dimensionality Effects

abstract:
  We report on a numerical study of quantum transport in disordered two
dimensional graphene and graphene nanoribbons. By using the Kubo and the
Landauer approaches, transport length scales in the diffusive (mean free path,
charge mobilities) and localized regimes (localization lengths) are computed,
assuming a short range disorder (Anderson-type). In agreement with localization
scaling theory, the electronic systems are found to undergo a conventional
Anderson localization in the zero temperature limit. Localization lengths in
weakly disordered ribbons are found to differ by two orders of magnitude
depending on their edge symmetry, but always remain several orders of magnitude
smaller than those computed for 2D graphene for the same disorder strength.
This pinpoints the role of transport dimensionality and edge effects.


title: Response, relaxation and transport in unconventional superconductors

abstract:
  We investigate the collision-limited electronic Raman response and the
attenuation of ultrasound in spin-singlet d-wave superconductors at low
temperatures. The dominating elastic collisions are treated within a t-matrix
approximation, which combines the description of weak (Born) and strong
(unitary) impurity scattering. In the long wavelength limit a two-fluid
description of both response and transport emerges. Collisions are here seen to
exclusively dominate the relaxational dynamics of the (Bogoliubov)
quasiparticle system and the analysis allows for a clear connection of response
and transport phenomena. When applied to quasi-2-d superconductors like the
cuprates, it turns out that the transport parameter associated with the Raman
scattering intensity for B1g and B2g photon polarization is closely related to
the corresponding components of the shear viscosity tensor, which dominates the
attenuation of ultrasound. At low temperatures we present analytic solutions of
the transport equations, resulting in a non-power-law behavior of the transport
parameters on temperature.


title:
Estimation of ordinal pattern probabilities in fractional Brownian
  motion

abstract:
  For equidistant discretizations of fractional Brownian motion (fBm), the
probabilities of ordinal patterns of order d=2 are monotonically related to the
Hurst parameter H. By plugging the sample relative frequency of those patterns
indicating changes between up and down into the monotonic relation to H, one
obtains the Zero Crossing (ZC) estimator of the Hurst parameter which has found
considerable attention in mathematical and applied research.
  In this paper, we generally discuss the estimation of ordinal pattern
probabilities in fBm. As it turns out, according to the sufficiency principle,
for ordinal patterns of order d=2 any reasonable estimator is an affine
functional of the sample relative frequency of changes. We establish strong
consistency of the estimators and show them to be asymptotically normal for
H<3/4. Further, we derive confidence intervals for the Hurst parameter.
Simulation studies show that the ZC estimator has larger variance but less bias
than the HEAF estimator of the Hurst parameter.


title:
Parametric and nonparametric models and methods in financial
  econometrics

abstract:
  Financial econometrics has become an increasingly popular research field. In
this paper we review a few parametric and nonparametric models and methods used
in this area. After introducing several widely used continuous-time and
discrete-time models, we study in detail dependence structures of discrete
samples, including Markovian property, hidden Markovian structure, contaminated
observations, and random samples. We then discuss several popular parametric
and nonparametric estimation methods. To avoid model mis-specification, model
validation plays a key role in financial modeling. We discuss several model
validation techniques, including pseudo-likelihood ratio test, nonparametric
curve regression based test, residuals based test, generalized likelihood ratio
test, simultaneous confidence band construction, and density based test.
Finally, we briefly touch on tools for studying large sample properties.


title: A Most General Edge Elimination Polynomial - Thickening of Edges

abstract:
  We consider a graph polynomial \xi(G;x,y,z) introduced by Averbouch, Godlin,
and Makowsky (2007). This graph polynomial simultaneously generalizes the Tutte
polynomial as well as a bivariate chromatic polynomial defined by Dohmen,
Poenitz and Tittmann (2003). We derive an identity which relates the graph
polynomial of a thicked graph (i.e. a graph with each edge replaced by k copies
of it) to the graph polynomial of the original graph. As a consequence, we
observe that at every point (x,y,z), except for points lying within some set of
dimension 2, evaluating \xi is #P-hard.


title: Isomorphisms of unitary forms of Kac-Moody groups over finite fields

abstract:
  We use methods developed by Caprace and M\"uhlherr to solve the isomorphism
problem of unitary forms of infinite split Kac-Moody groups over finite fields
of square order.


title: Singular perturbations and Lindblad-Kossakowski differential equations

abstract:
  We consider an ensemble of quantum systems whose average evolution is
described by a density matrix, solution of a Lindblad-Kossakowski differential
equation. We focus on the special case where the decoherence is only due to a
highly unstable excited state and where the spontaneously emitted photons are
measured by a photo-detector. We propose a systematic method to eliminate the
fast and asymptotically stable dynamics associated to the excited state in
order to obtain another differential equation for the slow part. We show that
this slow differential equation is still of Lindblad-Kossakowski type, that the
decoherence terms and the measured output depend explicitly on the amplitudes
of quasi-resonant applied field, i.e., the control. Beside a rigorous proof of
the slow/fast (adiabatic) reduction based on singular perturbation theory, we
also provide a physical interpretation of the result in the context of
coherence population trapping via dark states and decoherence-free subspaces.
Numerical simulations illustrate the accuracy of the proposed approximation for
a 5-level systems.


title: The three burials of Melquiades DGP

abstract:
  In this talk I review three fatal flaws of the DGP braneworld model, which
has been put forward as a possible model for late time acceleration without a
cosmological constant: Ghosts, Cosmological Crashes, and Instability of the 5D
vacuum. The talk is based on work in collaboration with Charmousis, Kaloper,
Myers and Padilla.


title: Methods for point source analysis in high energy neutrino telescopes

abstract:
  Neutrino telescopes are moving steadily toward the goal of detecting
astrophysical neutrinos from the most powerful galactic and extragalactic
sources. Here we describe analysis methods to search for high energy point-like
neutrino sources using detectors deep in the ice or sea. We simulate an ideal
cubic kilometer detector based on real world performance of existing detectors
such as AMANDA, IceCube, and ANTARES. An unbinned likelihood ratio method is
applied, making use of the point spread function and energy distribution of
simulated neutrino signal events to separate them from the background of
atmospheric neutrinos produced by cosmic ray showers. The unbinned point source
analyses are shown to perform better than binned searches and, depending on the
source spectral index, the use of energy information is shown to improve
discovery potential by almost a factor of two.


title: k-stabilization in brane models

abstract:
  Stabilization of inter-brane distance is analyzed in 5-dimensional models
with higher-order scalar kinetic terms. Equations of motion and boundary
conditions for background and for scalar perturbations are presented.
Conditions sufficient and (with one exception) necessary for stability are
derived and discussed. It is shown that it is possible to construct stable
brane configurations even without scalar potentials and cosmological constants.
As a byproduct we identify a large class of non-standard boundary conditions
for which the Sturm-Liouville operator is hermitian.


title: A Hadwiger-type theorem for the special unitary group

abstract:
  The dimension of the space of SU(n) and translation invariant continuous
valuations on $\mathbb{C}^n, n \geq 2$ is computed. For even $n$, this
dimension equals $(n^2+3n+10)/2$; for odd $n$ it equals $(n^2+3n+6)/2$. An
explicit geometric basis of this space is constructed. The kinematic formulas
for SU(n) are obtained as corollaries.


title: Random subgraphs of the 2D Hamming graph: the supercritical phase

abstract:
  We study random subgraphs of the 2-dimensional Hamming graph H(2,n), which is
the Cartesian product of two complete graphs on $n$ vertices. Let $p$ be the
edge probability, and write $p=\frac{1+\vep}{2(n-1)}$ for some $\vep\in \R$. In
Borgs et al., Random subgraphs of finite graphs: I. The scaling window under
the triangle condition, Rand. Struct. Alg. (2005), and in Borgs et al., Random
subgraphs of finite graphs: II. The lace expansion and the triangle condition,
Ann. Probab. (2005), the size of the largest connected component was estimated
precisely for a large class of graphs including H(2,n) for $\vep\leq \Lambda
V^{-1/3}$, where $\Lambda > 0$ is a constant and $V=n^2$ denotes the number of
vertices in H(2,n). Until now, no matching lower bound on the size in the
supercritical regime has been obtained.
  In this paper we prove that, when $\vep\gg (\log{V})^{1/3} V^{-1/3}$, then
the largest connected component has size close to $2\vep V$ with high
probability. We thus obtain a law of large numbers for the largest connected
component size, and show that the corresponding values of $p$ are
supercritical. Barring the factor $(\log{\chs{V}})^{1/3}$, this identifies the
size of the largest connected component all the way down to the critical $p$
window.


title: The second largest component in the supercritical 2D Hamming graph

abstract:
  The 2-dimensional Hamming graph H(2,n) consists of the $n^2$ vertices
$(i,j)$, $1\leq i,j\leq n$, two vertices being adjacent when they share a
common coordinate. We examine random subgraphs of H(2,n) in percolation with
edge probability $p$, so that the average degree $2(n-1)p=1+\epsilon$. Previous
work by van der Hofstad and Luczak had shown that in the barely supercritical
region $n^{-2/3}\ln^{1/3}n\ll \epsilon \ll 1$ the largest component has size
$\sim 2\epsilon n$. Here we show that the second largest component has size
close to $\epsilon^{-2}$, so that the dominant component has emerged. This
result also suggests that a {\it discrete duality principle} might hold,
whereby, after removing the largest connected component in the supercritical
regime, the remaining random subgraphs behave as in the subcritical regime.


title: Cyclic dominance and biodiversity in well-mixed populations

abstract:
  Coevolutionary dynamics is investigated in chemical catalysis, biological
evolution, social and economic systems. The dynamics of these systems can be
analyzed within the unifying framework of evolutionary game theory. In this
Letter, we show that even in well-mixed finite populations, where the dynamics
is inherently stochastic, biodiversity is possible with three cyclic dominant
strategies. We show how the interplay of evolutionary dynamics, discreteness of
the population, and the nature of the interactions influences the coexistence
of strategies. We calculate a critical population size above which coexistence
is likely.


title: Character of eigenstates of the 3D disordered Anderson Hamiltonian

abstract:
  We study numerically the character of electron eigenstates of the three
dimensional disordered Anderson model. Analysis of the statistics of inverse
participation ratio as well as numerical evaluation of the electron-hole
correlation function confirm that there are no localized states below the
mobility edge, as well as no metallic state in the tail of the conductive band.
We discuss also finite size effects observed in the analysis of all the
discussed quantities.


title: On the origin of the Raman scattering in heavily boron-doped diamond

abstract:
  Isotopic substitution of boron and carbon is applied for the identification
of the vibrational modes of heavily boron-doped diamond synthesized by
high-pressure high-temperature technique. None of the bands in the Raman
spectra are shifting upon ^{10}B-substitution, whereas shifts to lower
frequency are observed for all bands upon ^{13}C-substitution as compared to a
sample with natural isotope abundancies. These isotopic substitution
experiments exclude the hypothesis of boron dimer related normal modes and
strongly support the assignment of the previously studied "500 cm^{-1}" and
"1230 cm^{-1}" bands and two weak bands at 1003 cm^{-1} and 1070 cm^{-1} to
perturbed diamond lattice phonons, revealing the phonon density of states. A
second-order phonon spectrum at combination and overtone frequencies is also
identified. A bulk plasmon related mechanism is proposed for the enhancement of
the phonon density of states spectrum relative to the zone-center phonons.


title: A geometric preferential attachment model with fitness

abstract:
  We study a random graph $G_n$, which combines aspects of geometric random
graphs and preferential attachment. The resulting random graphs have power-law
degree sequences with finite mean and possibly infinite variance. In
particular, the power-law exponent can be any value larger than 2.
  The vertices of $G_n$ are $n$ sequentially generated vertices chosen at
random in the unit sphere in $\mathbb R^3$. A newly added vertex has $m$ edges
attached to it and the endpoints of these edges are connected to old vertices
or to the added vertex itself. The vertices are chosen with probability
proportional to their current degree plus some initial attractiveness and
multiplied by a function, depending on the geometry.


title:
Quantum Transport Length Scales in Silicon-based Semiconducting
  Nanowires: Surface Roughness Effects

abstract:
  We report on a theoretical study of quantum charge transport in atomistic
models of silicon nanowires with surface roughness-based disorder. Depending on
the nanowires features (length, roughness profile) various conduction regimes
are explored numerically by using efficient real space order N computational
approaches of both Kubo-Greenwood and Landauer-Buttiker transport frameworks.
Quantitative estimations of the elastic mean free paths, charge mobilities and
localization lengths are performed as a function of the correlation length of
the surface roughness disorder. The obtained values for charge mobilities well
compare with the experimental estimates of the most performant undoped
nanowires. Further the limitations of the Thouless relationship between the
mean free path and the localization length are outlined.


title: Di-electron and two-photon widths in charmonium

abstract:
  The vector and pseudoscalar decay constants are calculated in the framework
of the Field Correlator Method. Di-electron widths: $\Gamma_{ee}(J/\psi)=5.41$
keV, $\Gamma_{ee}(\psi'(3686))=2.47$ keV, $\Gamma_{ee}(\psi''(3770))=0.248$
keV, in good agreement with experiment, are obtained with the same coupling,
$\alpha_s=0.165$, in QCD radiative corrections. We show that the larger
$\alpha_s=0.191\pm 0.004$ is needed to reach agreement with experiment for
$\Gamma_{\gamma\gamma}(\eta_c)=7.22$ keV, $\Gamma_{\gamma\gamma}
(\chi(^3P_0))=3.3$ keV, $\Gamma_{\gamma\gamma}(\chi(^3P_2))= 0.54$ keV, and
also for $\Gamma(J/\psi\to 3g)=59.5$ keV, $\Gamma(J/\psi\to \gamma 2g)=5.7$
keV. Meanwhile even larger $\alpha_s=0.238$ gives rise to good description of
$\Gamma(\psi'\to 3g)=52.7$ keV, $\Gamma(\psi'\to \gamma 2g)= 3.5$ keV, and
provides correct ratio of the branching fractions: $\frac{\mathcal{B}(J/\psi\to
light hadrons)}{\mathcal{B}(\psi'\to light hadrons)}=0.24.$


title: A Lorentz Invariant Pairing Mechanism: Relativistic Cooper Pairs

abstract:
  We study a Lorentz invariant pairing mechanism that arises when two
relativistic spin-1/2 fermions are subjected to a Dirac string coupling. In the
weak coupling regime, we find remarkable analogies between this relativistic
bound system and the well known superconducting Cooper pair. As the coupling
strength is raised, quenched phonons become unfrozen and dynamically contribute
to the gluing mechanism, which translates into novel features of this
relativistic superconducting pair.

categories: cond-mat.supr-con cond-mat.str-el hep-th quant-ph


title: Next-to-leading order multi-leg processes for the Large Hadron Collider

abstract:
  In this talk we discuss recent progress concerning precise predictions for
the LHC. We give a status report of three applications of our method to deal
with multi-leg one-loop amplitudes: The interference term of Higgs production
by gluon- and weak boson fusion to order O(alpha^2 alpha_s^3) and the
next-to-leading order corrections to the two processes pp -> ZZ jet and u ubar
-> d dbar s sbar. The latter is a subprocess of the four jet cross section at
the LHC.


title: Fourier transform, null variety, and Laplacian's eigenvalues

abstract:
  We consider a quantity $\kappa(\Omega)$ -- the distance to the origin from
the null variety of the Fourier transform of the characteristic function of
$\Omega$. We conjecture, firstly, that $\kappa(\Omega)$ is maximized, among all
convex balanced domains $\Omega\subset\Rbb^d$ of a fixed volume, by a ball, and
also that $\kappa(\Omega)$ is bounded above by the square root of the second
Dirichlet eigenvalue of $\Omega$. We prove some weaker versions of these
conjectures in dimension two, as well as their validity for domains
asymptotically close to a disk, and also discuss further links between
$\kappa(\Omega)$ and the eigenvalues of the Laplacians.


title: The fall speeds of sub-100 micron ice crystals

abstract:
  Estimates for the sedimentation rate of realistic ice crystals at sizes
smaller than 100 $\mu$m are presented. These calculations, which exploit new
results for the capacitance of ice crystals, are compared with laboratory
studies and found to be in good agreement. The results highlight a weakness in
contemporary ice particle fall speed parameterisations for very small crystals,
which can lead to sedimentation rates being overestimated by a factor of two.
The theoretical approach applied here may also be useful for calculating the
sedimentation rate and mobility of non-spherical aerosol particles.


title: Overview and Perspectives in Nuclear Physics

abstract:
  This presentation reviews recent guiding themes in the broad context of
nuclear physics, from developments in chiral effective field theory applied to
nuclear systems, via the phases and structures of QCD, to matter under extreme
conditions in heavy-ion collisions and neutron stars.


title: On colored Turaev-Viro invariants for links in arbitrary 3-manifolds

abstract:
  We consider certain invariants of links in 3-manifolds, obtained by a
specialization of the Turaev-Viro invariants of 3-manifolds, that we call
colored Turaev-Viro invariants. Their construction is based on a presentation
of a pair (M,L), where M is a closed oriented 3-manifold and L is an oriented
link in M, by a triangulation of M such that each component of L is an edge. We
analyze some basic properties of these invariants, including the behavior under
connected sums of pairs away and along links. These properties allow us to
provide examples of links in the three-sphere having the same HOMFLY polynomial
and the same Kauffman polynomial but distinct Turaev-Viro invariants, and
similar examples for the Alexander polynomial. We also investigate the
relations between the Turaev-Viro invariants of (M,L) and those of the
complement of L in M, showing that they are sometimes but not always determined
by each other.


title: On the structure of the necklace Lie algebra

abstract:
  In this note, we initiate the systematic study of the Lie algebra structure
of the necklace Lie algebra n of a free algebra in 2d variables. We begin by
giving a description of n as an sp(2d)-module. Specializing to d = 1, we
decompose n into a direct sum of highest weight modules for sl_2, the
coefficients of which are given by a closed formula. Next, we observe that n
has a nontrivial center, which we link through the center C of the trace ring
of couples of generic 2x2 matrices to the Poisson center of S(sl_2). The Lie
algebra structure of n induces a Poisson structure on C, the symplectic leaves
of which we are able to describe as coadjoint orbits for the Lie group of the
semidirect product sl_2\rtimes h of sl_2 with the Heisenberg Lie algebra h.
Finally, we provide a link between double Poisson algebras on one hand and
Poisson orders on the other hand, showing that all trace rings of a double
Poisson algebra are Poisson orders over their center.


title:
Mixing in the Solar Nebula: Implications for Isotopic Heterogeneity and
  Large-Scale Transport of Refractory Grains

abstract:
  The discovery of refractory grains amongst the particles collected from Comet
81P/Wild 2 by the Stardust spacecraft (Brownlee et al. 2006) provides the
ground truth for large-scale transport of materials formed in high temperature
regions close to the protosun outward to the comet-forming regions of the solar
nebula. While accretion disk models driven by a generic turbulent viscosity
have been invoked as a means to explain such large-scale transport, the
detailed physics behind such an ``alpha'' viscosity remains unclear. We present
here an alternative physical mechanism for large-scale transport in the solar
nebula: gravitational torques associated with the transient spiral arms in a
marginally gravitationally unstable disk, of the type that appears to be
necessary to form gas giant planets. Three dimensional models are presented of
the time evolution of self-gravitating disks, including radiative transfer and
detailed equations of state, showing that small dust grains will be transported
upstream and downstream (with respect to the mean inward flow of gas and dust
being accreted by the central protostar) inside the disk on time scales of less
than 1000 yr inside 10 AU. These models furthermore show that any initial
spatial heterogeneities present (e.g., in short-lived isotopes such as 26Al)
will be homogenized by disk mixing down to a level of ~10%, preserving the use
of short-lived isotopes as accurate nebular chronometers, while simultaneously
allowing for the spread of stable oxygen isotope ratios. This finite level of
nebular spatial heterogeneity appears to be related to the coarse mixing
achieved by spiral arms, with radial widths of order 1 AU, over time scales of
~1000 yrs.


title: Bound of dissipation on a plane Couette dynamo

abstract:
  Variational turbulence is among the few approaches providing rigorous results
in turbulence. In addition, it addresses a question of direct practical
interest, namely the rate of energy dissipation. Unfortunately, only an upper
bound is obtained as a larger functional space than the space of solutions to
the Navier-Stokes equations is searched. Yet, in general, this upper bound is
in good agreement with experimental results in terms of order of magnitude and
power law of the imposed Reynolds number. In this paper, the variational
approach to turbulence is extended to the case of dynamo action and an upper
bound is obtained for the global dissipation rate (viscous and Ohmic). A simple
plane Couette flow is investigated. For low magnetic Prandtl number $P_m$
fluids, the upper bound of energy dissipation is that of classical turbulence
(i.e. proportional to the cubic power of the shear velocity) for magnetic
Reynolds numbers below $P_m^{-1}$ and follows a steeper evolution for magnetic
Reynolds numbers above $P_m^{-1}$ (i.e. proportional to the shear velocity to
the power four) in the case of electrically insulating walls. However, the
effect of wall conductance is crucial : for a given value of wall conductance,
there is a value for the magnetic Reynolds number above which energy
dissipation cannot be bounded. This limiting magnetic Reynolds number is
inversely proportional to the square root of the conductance of the wall.
Implications in terms of energy dissipation in experimental and natural dynamos
are discussed.


title: The Maximum Patch Method for Directional Dark Matter Detection

abstract:
  Present and planned dark matter detection experiments search for WIMP-induced
nuclear recoils in poorly known background conditions. In this environment, the
maximum gap statistical method provides a way of setting more sensitive cross
section upper limits by incorporating known signal information. We give a
recipe for the numerical calculation of upper limits for planned directional
dark matter detection experiments, that will measure both recoil energy and
angle, based on the gaps between events in two-dimensional phase space.


title:
Sequential and Spontaneous Star Formation Around the Mid-Infrared Halo
  HII Region KR 140

abstract:
  We use 2MASS and MSX infrared observations, along with new molecular line
(CO) observations, to examine the distribution of young stellar objects (YSOs)
in the molecular cloud surrounding the halo HII region KR 140 in order to
determine if the ongoing star-formation activity in this region is dominated by
sequential star formation within the photodissociation region (PDR) surrounding
the HII region. We find that KR 140 has an extensive population of YSOs that
have spontaneously formed due to processes not related to the expansion of the
HII region. Much of the YSO population in the molecular cloud is concentrated
along a dense filamentary molecular structure, traced by C18O, that has not
been erased by the formation of the exciting O star. Some of the previously
observed submillimetre clumps surrounding the HII region are shown to be sites
of recent intermediate and low-mass star formation while other massive starless
clumps clearly associated with the PDR may be the next sites of sequential star
formation.


title: Linear and Nonlinear Optical constants of BiFeO_3

abstract:
  Using spectroscopic ellipsometry, the refractive index and absorption versus
wavelength of the ferroelectric antiferromagnet Bismuth Ferrite, BiFeO_3 is
reported. The material has a direct band-gap at 442 nm wavelength (2.81 eV).
Using optical second harmonic generation, the nonlinear optical coefficients
were determined to be d_15/d_22 = 0.20 +/- 0.01, d_31/d_22 = 0.35 +/- 0.02,
d_33/d_22 = -11.4 +/- 0.20 and |d_22| = 298.4 +/- 6.1 pm/V at a fundamental
wavelength of 800 nm.


title:
The Calogero-Moser partition and Rouquier families for complex
  reflection groups

abstract:
  Let $W$ be a complex reflection group. We formulate a conjecture relating
blocks of the corresponding restricted rational Cherednik algebras and Rouquier
families for cyclotomic Hecke algebras. We verify the conjecture in the case
that $W$ is a wreath product of a symmetric group with a cyclic group of order
$l$.


title:
Fluctuations driven isotropization of the quark-gluon plasma in heavy
  ion collisions

abstract:
  Averaged over ensemble of initial conditions kinetic transport equations of
weakly coupled systems of quarks and gluons are derived. These equations
account for the correlators of fluctuations of particles and classical gluon
fields. The isotropization of particle momenta by field fluctuations at the
early prethermal stage of matter evolution in ultrarelativistic heavy ion
collisions is discussed. Our results can be useful for understanding under what
conditions isotropization of the quark-gluon plasma in ultrarelativistic heavy
ion collisions can be reached within phenomenologically observed time scales.


title:
Analytical view of diffusive and convective cosmic ray transport in
  elliptical galaxies

abstract:
  Context: An analytical solution of the generalized diffusive and convective
transport equation is derived to explain the transport of cosmic ray protons
within elliptical galaxies. Aims: Cosmic ray transport within elliptical
galaxies is an interesting element in understanding the origin of high
energetic particles measured on Earth. As probable sources of those high
energetic particles, elliptical galaxies show a dense interstellar medium as a
consequence of activity in the galactic nucleus or merging events between
galaxies. Thus it is necessary for an appropriate description of cosmic ray
transport to take the diffusive and convective processes in a dense
interstellar environment into account. Here we show that the transport
equations can be solved analytically with respect to the given geometry and
boundary conditions in position space, as well as in momentum space. Results:
The spatial solution is shown using a generalized source of cosmic rays.
Additionally, the special case of a jet-like source is illustrated. We present
the solution in momentum space with respect to an escape term for cosmic ray
protons depending on the spatial shape of the galaxy. For a delta-shape
injection function, the momentum solution is obtained analytically. We find
that the spectral index measured on Earth can be obtained by appropriately
choosing of the strength of Fermi I and Fermi II processes. From these results
we calculate the gamma-ray flux from pion decay due to proton-proton
interaction to give connection to observations. Additionally we determine the
escape-spectrum of cosmic rays. The results show that both spectra are harder
than the intrinsic power-law spectrum for cosmic rays in elliptical galaxies.


title: Computational Solutions for Today's Navy

abstract:
  New methods are being employed to meet the Navy's changing
software-development environment.


title: Cross-correlation of two interacting conductors

abstract:
  We calculate the current cross-correlation for two weakly interacting
mesoscopic conductors. Our derivation is based on the two-particle scattering
matrix derived in Goorden and B\"uttiker [Phys. Rev. Lett. {\bf 99}, 146801
(2007)]. We include the Fermi sea in the leads into the theory and show how to
calculate transport quantities and specifically cross-correlations. We focus on
the zero-frequency current cross-correlation of two chaotic quantum dots and
calculate the magnitude of its fluctuations with the help of Random Matrix
Theory.


title: Uppers to zero in polynomial rings and Pr\"ufer-like domains

abstract:
  Let $D$ be an integral domain and $X$ an indeterminate over $D$. It is well
known that (a) $D$ is quasi-Pr\"ufer (i.e, its integral closure is a Pr\"ufer
domain) if and only if each upper to zero $Q$ in $D[X] $ contains a polynomial
$g \in D[X]$ with content $\co_D(g) = D$; (b) an upper to zero $Q$ in $D[X]$ is
a maximal $t$-ideal if and only if $Q$ contains a nonzero polynomial $g \in
D[X]$ with $\co_D(g)^v = D$. Using these facts, the notions of UM$t$-domain
(i.e., an integral domain such that each upper to zero is a maximal $t$-ideal)
and quasi-Pr\"ufer domain can be naturally extended to the semistar operation
setting and studied in a unified frame. In this paper, given a semistar
operation $\star$ in the sense of Okabe-Matsuda, we introduce the
$\star$-quasi-Pr\"ufer domains. We give several characterizations of these
domains and we investigate their relations with the UM$t$-domains and the
Pr\"ufer $v$-multiplication domains.


title: Near-infrared, IFU spectroscopy unravels the bow-shock HH99B

abstract:
  We aim to characterise the morphology and the physical parameters governing
the shock physics of the Herbig-Haro object HH99B. We have obtained
SINFONI-SPIFFI IFU spectroscopy between 1.10 and 2.45 um detecting more than
170 emission lines, Most of them come from ro-vibrational transitions of H_2
and [FeII]. All the brightest lines appear resolved in velocity. Intensity
ratios of ionic lines have been compared with predictions of NLTE models to
derive bi-dimensional maps of extinction and electron density, along with
estimates of temperature, fractional ionisation and atomic hydrogen post-shock
density. H_2 line intensities have been interpreted in the framework of
Boltzmann diagrams, from which we have derived maps of extinction and
temperature of the molecular gas. From the intensity maps of bright lines the
kinematical properties of the shock(s) at work in the region have been
delineated. Finally, from selected [FeII] lines, constraints on the spontaneous
emission coefficients of the 1.257, 1.321 and 1.644 um lines are provided. The
kinematical properties derived for the molecular gas substantially confirm
those published in Davis et al.(1999), while new information (e.g. v_shock ~115
km s^-1 is provided for the shock component responsible for the ionic emission.
We also provide an indirect measure of the H_2 breakdown speed (between 70 and
90 km s^-1) and compute the inclination angle with respect to the line of
sight. The map parameters, along with images of the observed line intensities,
will be used to put stringent constraints on up-to-date shock models.


title: Cohomological invariants of odd degree Jordan algebras

abstract:
  In this paper we determine all possible cohomological invariants of
Aut(J)-torsors in Galois cohomology with mod 2 coefficients (characteristic of
the base field not 2), for J a split central simple Jordan algebra of odd
degree n>=3. This has already been done for J of orthogonal and exceptional
type, and we extend these results to unitary and symplectic type. We will use
our results to compute the essential dimensions of some groups, for example we
show that ed(PSp(2n))=n+1 for n odd.


title: Chain recurrence rates and topological entropy

abstract:
  We investigate the properties of chain recurrent, chain transitive, and chain
mixing maps (generalizations of the well-known notions of non-wandering,
topologically transitive, and topologically mixing maps). We describe the
structure of chain transitive maps. These notions of recurrence are defined
using $\ep$-chains, and the minimal lengths of these $\ep$-chains give a way to
measure recurrence time (chain recurrence and chain mixing times). We give
upper and lower bounds for these recurrence times and relate the chain mixing
time to topological entropy.


title:
Massive Infrared-Quiet Dense Cores: Unveiling the Initial Conditions of
  High-Mass Star Formation

abstract:
  As Pr. Th. Henning said at the conference, cold precursors of high-mass stars
are now "hot topics". We here propose some observational criteria to identify
massive infrared-quiet dense cores which can host the high-mass analogs of
Class 0 protostars and pre-stellar condensations. We also show how far-infrared
to millimeter imaging surveys of entire complexes forming OB stars are starting
to unveil the initial conditions of high-mass star formation.


title:
The magneto-rotational instability near threshold: spatio-temporal
  amplitude equation and saturation

abstract:
  We show, by means of a perturbative weakly nonlinear analysis, that the
axisymmetric magneto-rotational instability (MRI) in a magnetic Taylor-Couette
(mTC) flow in a thin-gap gives rise, for very small magnetic Prandtl numbers
(P_m), to a real Ginzburg-Landau equation for the disturbance amplitude. The
saturation amplitude A_s is found to scale in this regime as P^\delta, with
1/2<\delta<2/3 (depending on the boundary conditions adopted). The asymptotic
results are shown to comply with numerical calculations performed by using a
spectral code. They suggest that the transport due to the nonlinearly developed
MRI may be vanishingly small for P_m << 1.


title:
Nonequilibrium sum rules for the retarded self-energy of strongly
  correlated electrons

abstract:
  We derive the first two moment sum rules of the conduction electron retarded
self-energy for both the Falicov-Kimball model and the Hubbard model coupled to
an external spatially uniform and time-dependent electric field (this
derivation also extends the known nonequilibrium moment sum rules for the
Green's functions to the third moment). These sum rules are used to further
test the accuracy of nonequilibrium solutions to the many-body problem; for
example, we illustrate how well the self-energy sum rules are satisfied for the
Falicov-Kimball model in infinite dimensions and placed in a uniform electric
field turned on at time t=0. In general, the self-energy sum rules are
satisfied to a significantly higher accuracy than the Green's functions sum
rules.


title: Itineraries of rigid rotations and diffeomorphisms of the circle

abstract:
  We examine the itinerary of $0\in S^{1}=\R/\Z$ under the rotation by
$\alpha\in\R\bs\Q$. The motivating question is: if we are given only the
itinerary of 0 relative to $I\subset S^{1}$, a finite union of closed
intervals, can we recover $\alpha$ and $I$? We prove that the itineraries do
determine $\alpha$ and $I$ up to certain equivalences. Then we present
elementary methods for finding $\alpha$ and $I$. Moreover, if $g:S^{1}\to
S^{1}$ is a $C^{2}$, orientation preserving diffeomorphism with an irrational
rotation number, then we can use the orbit itinerary to recover the rotation
number up to certain equivalences.


title: Globular Clusters and X-ray Point Sources in Centaurus A (NGC 5128)

abstract:
  We detect 353 X-ray point sources, mostly low-mass X-ray binaries (LMXBs), in
four Chandra observations of Centaurus A (NGC 5128), the nearest giant
early-type galaxy, and correlate this point source population with the largest
available ensemble of confirmed and likely globular clusters associated with
this galaxy. Of the X-ray sources, 31 are coincident with 30 globular clusters
that are confirmed members of the galaxy by radial velocity measurement (2
X-ray sources match one globular cluster within our search radius), while 1
X-ray source coincides with a globular cluster resolved by HST images. Another
36 X-ray point sources match probable, but spectroscopically unconfirmed,
globular cluster candidates. The color distribution of globular clusters and
cluster candidates in Cen A is bimodal, and the probability that a red, metal
rich GC candidate contains an LMXB is at least 1.7 times that of a blue, metal
poor one. If we consider only spectroscopically confirmed GCs, this ratio
increases to ~3. We find that LMXBs appear preferentially in more luminous
(massive) GCs. These two effects are independent, and the latter is likely a
consequence of enhanced dynamical encounter rates in more massive clusters
which have on average denser cores. The X-ray luminosity functions of the LMXBs
found in GCs and of those that are unmatched with GCs reveal similar underlying
populations, though there is some indication that fewer X-ray faint LMXBs are
found in globular clusters than X-ray bright ones. Our results agree with
previous observations of the connection of GCs and LMXBs in early-type galaxies
and extend previous work on Centaurus A.


title: Non-linear dynamics of absorption and photo-bleaching of dyes

abstract:
  The celebrated Lambert-Beer law of light absorption in photochromic media is
only valid at low intensities of incident light and low concentration of
chromophore. Here we address the generic problem of photo-absorption dynamics,
experimentally studying the case of azobenzene isomerization. We show that the
non-linear regime is very common and easy to achieve in many practical
situations, especially in thick samples where the light depletes the
chromophore in the first layers and can propagate through the medium with a
sub-exponential law. Importantly, the crossover into the non-linear absorption
regime only weakly depends on the dye concentration and solution viscosity. We
experimentally quantify the characteristics of this peculiar optical response
and determine the key transition rate constants.


title: Vibrational Bloch-Siegert effect in trapped ions

abstract:
  When trapped atoms are illuminated by weak lasers, off-resonant transitions
cause shifts in the frequencies of the vibrational-sideband resonances. These
frequency shifts may be understood in terms of Stark-shifts of the individual
levels or, as proposed here, as a vibrational Bloch-Siegert shift, an effect
closely related to the usual (radio-frequency or optical) Bloch-Siegert shift
and associated with rapidly oscillating terms when the Rotating Wave
Approximation is not made. Explicit analytic expressions are derived and
compared to numerical results, and the similarities and differences between the
usual and the vibrational Bloch-Siegert shifts are also spelled out.


title:
The Reduction of the Electron Abundance during the Pre-explosion
  Simmering in White Dwarf Supernovae

abstract:
  Prior to the explosion of a carbon-oxygen white dwarf in a Type Ia supernova
there is a long "simmering," during which the 12C + 12C reaction gradually
heats the white dwarf on a long (~ 1000 yr) timescale. Piro & Bildsten showed
that weak reactions during this simmering set a maximum electron abundance Ye
at the time of the explosion. We investigate the nuclear reactions during this
simmering with a series of self-heating, at constant pressure, reaction network
calculations. Unlike in AGB stars, proton captures onto 22Ne and heavier trace
nuclei do not play a significant role. The 12C abundance is sufficiently high
that the neutrons preferentially capture onto 12C, rather than iron group
nuclei. As an aid to hydrodynamical simulations of the simmering phase, we
present fits to the rates of heating, electron capture, change in mean atomic
mass, and consumption of 12C in terms of the screened thermally averaged cross
section for 12C + 12C. Our evaluation of the net heating rate includes
contributions from electron captures into the 3.68 MeV excited state of 13C.
This results in a slightly larger energy release, per 12C consumed, than that
found by Piro & Bildsten, but less than that released for a burn to only 20Ne
and 23Na. We compare our one-zone results to more accurate integrations over
the white dwarf structure to estimate the amount of 12C that must be consumed
to raise the white dwarf temperature, and hence to determine the net reduction
of Ye during simmering.


title: Failure of intuition in elementary rigid body dynamics

abstract:
  Suppose a projectile collides perpendicularly with a stationary rigid rod on
a smooth horizontal table. We show that, contrary to what one naturally
expects, it is not always the case that the rod acquires maximum angular
velocity when struck at an extremity. The treatment is intended for first year
university students of Physics or Engineering, and could form the basis of a
tutorial discussion of conservation laws in rigid body dynamics.


title:
Dark Matter and Electroweak Symmetry Breaking in Models with Warped
  Extra Dimensions

abstract:
  We show that a discrete exchange symmetry can give rise to realistic dark
matter candidates in models with warped extra dimensions. We show how to
realize our construction in a variety of models with warped extra dimensions
and study in detail a realistic model of Gauge-Higgs Unification/composite
Higgs in which the observed amount of dark matter is naturally reproduced. In
this model, a realistic pattern of electroweak symmetry breaking typically
occurs in a region of parameter space in which the fit to the electroweak
precision observables improves, the Higgs is heavier than the experimental
bound and new light quark resonances are predicted. We also quantify the
fine-tuning of such scenarios, and discuss in which sense Gauge-Higgs
Unification models result in a natural theory of electroweak symmetry breaking.


title: Particle-hole symmetry and the dirty boson problem

abstract:
  We study the role of particle-hole symmetry on the universality class of
various quantum phase transitions corresponding to the onset of superfluidity
at zero temperature of bosons in a quenched random medium. The functional
integral formulation of this problem in d spatial dimensions yields a
(d+1)-dimensional classical XY-model with extended disorder--the so-called
random rod problem. Particle-hole symmetry may then be broken by adding nonzero
site energies. We may distinguish three cases: (i) exact particle-hole
symmetry, in which the site energies all vanish, (ii) statistical particle-hole
symmetry in which the site energy distribution is symmetric about zero,
vanishing on average, and (iii) complete absence of particle-hole symmetry in
which the distribution is generic. We explore in each case the nature of the
excitations in the non-superfluid Mott insulating and Bose glass phases. We
find that the Bose glass compressibility, which has the interpretation of a
temporal spin stiffness or superfluid density, is positive in cases (ii) and
(iii), but that it vanishes with an essential singularity as full particle-hole
symmetry is restored. We then focus on the critical point and discuss the
relevance of type (ii) particle-hole symmetry breaking perturbations to the
random rod critical behavior. We argue that a perturbation of type (iii) is
irrelevant to the resulting type (ii) critical behavior: the statistical
symmetry is restored on large scales close to the critical point, and case (ii)
therefore describes the dirty boson fixed point. To study higher dimensions we
attempt, with partial success, to generalize the Dorogovtsev-Cardy-Boyanovsky
double epsilon expansion technique to this problem. The qualitative
renormalization group flow picture this technique provides is quite compelling.


title:
Extending the definition of modularity to directed graphs with
  overlapping communities

abstract:
  Complex networks topologies present interesting and surprising properties,
such as community structures, which can be exploited to optimize communication,
to find new efficient and context-aware routing algorithms or simply to
understand the dynamics and meaning of relationships among nodes. Complex
networks are gaining more and more importance as a reference model and are a
powerful interpretation tool for many different kinds of natural, biological
and social networks, where directed relationships and contextual belonging of
nodes to many different communities is a matter of fact. This paper starts from
the definition of modularity function, given by M. Newman to evaluate the
goodness of network community decompositions, and extends it to the more
general case of directed graphs with overlapping community structures.
Interesting properties of the proposed extension are discussed, a method for
finding overlapping communities is proposed and results of its application to
benchmark case-studies are reported. We also propose a new dataset which could
be used as a reference benchmark for overlapping community structures
identification.


title:
Comment on "Resolving the sign ambiguity in $\Delta \Gamma_s$ with $B_s
  \to D_s K$"

abstract:
  This is a comment on the recent paper by Soumitra Nandi1 and Ulrich Nierste
``Resolving the sign ambiguity in $\Delta \Gamma_s$ with $B_s \to D_s K$'',
arXiv:0801.0143 [hep-ph].


title: A flux emergence model for solar eruptions

abstract:
  We have simulated the 3D emergence and interaction of two twisted flux tubes,
which rise from the interior into the outer atmosphere of the Sun. We present
evidence for the multiple formation and eruption of flux ropes inside the
emerging flux systems and hot arcade-like structures in between them. Their
formation is due to internal reconnection, occurring between oppositely
directed, highly stretched and sheared fieldlines at photospheric heights. Most
of the eruptions escape into the corona, but some are confined and fade away
without leaving the low atmosphere. As these flux ropes erupt, new reconnected
fieldlines accumulate around the main axis of the initial magnetic flux
systems. We also show the complex 3D fieldline geometry and the structure of
the multiple current sheets, which form as a result of the reconnection between
the emerging flux systems.


title:
Leading coefficients of Kazhdan--Lusztig polynomials and fully
  commutative elements

abstract:
  Let $W$ be a Coxeter group of type $\widetilde{A}_{n-1}$. We show that the
leading coefficient, $\mu(x, w)$, of the Kazhdan--Lusztig polynomial $P_{x, w}$
is always equal to 0 or 1 if $x$ is fully commutative (and $w$ is arbitrary).


title:
Sparticle Discovery Potentials in the CMSSM and GUT-less
  Supersymmetry-Breaking Scenarios

abstract:
  We consider the potentials of the LHC and a linear e^+e^- collider (LC) for
discovering supersymmetric particles in variants of the MSSM with soft
supersymmetry-breaking mass parameters constrained to be universal at the GUT
scale (CMSSM) or at some lower scale M_{in} (GUT-less models), as may occur in
some scenarios with mirage unification. Whereas the LHC should be able to
discover squarks and/or gluinos along all the CMSSM coannihilation strip where
the relic neutralino LSP density lies within the range favoured for cold dark
matter, many GUT-less models could escape LHC detection. In particular, if
M_{in} < 10^{11} GeV, the LHC would not detect sparticles if the relic density
lies within the favoured range. For any given discovery of supersymmetry at the
LHC, in such GUT-less models the lightest neutralino mass and hence the
threshold for sparticle pair production at a LC increases as M_{in} decreases,
and the CMSSM offers the best prospects for measuring sparticles at a LC. For
example, if the LHC discovers sparticles with 1 fb^{-1} of data, within the
CMSSM a centre-of-mass energy of 600 GeV would suffice for a LC to to produce
pairs of neutralinos, if they provide the cold dark matter, whereas over 1 TeV
might be required in a general GUT-less model. These required energies increase
to 800 GeV in the CMSSM and 1.4 TeV in GUT-less models if the LHC requires 10
fb^{-1} to discover supersymmetry.


title:
A note on the relationship between the Graphical Traveling Salesman
  Polyhedron, the Symmetric Traveling Salesman Polytope, and the Metric Cone

abstract:
  In this short communication, we observe that the Graphical Traveling Salesman
Polyhedron is the intersection of the positive orthant with the Minkowski sum
of the Symmetric Traveling Salesman Polytope and the polar of the metric cone.
This follows almost trivially from known facts. There are two reasons why we
find this observation worth communicating none-the-less: It is very surprising;
it helps to understand the relationship between these two important families of
polyhedra.


title: Nuclear constraints on the momenta of inertia of neutron stars

abstract:
  Properties and structure of neutron stars are determined by the equation of
state (EOS) of neutron-rich stellar matter. While the collective flow and
particle production in relativistic heavy-ion collisions have constrained
tightly the EOS of symmetric nuclear matter up to about five times the normal
nuclear matter density, the more recent experimental data on isospin-diffusion
and isoscaling in heavy-ion collisions at intermediate energies have
constrained considerably the density dependence of the nuclear symmetry energy
at subsaturation densities. Although there are still many uncertainties and
challenges to pin down completely the EOS of neutron-rich nuclear matter, the
heavy-ion reaction experiments in terrestrial laboratories have limited the EOS
of neutron-rich nuclear matter in a range much narrower than that spanned by
various EOSs currently used in astrophysical studies in the literature. These
nuclear physics constraints could thus provide more reliable information about
properties of neutron stars. Within well established formalisms using the
nuclear constrained EOSs we study the momenta of inertia of neutron stars. We
put the special emphasis on the component A of the extremely relativistic
double neutron star system PSR J0737-3039. Its moment of inertia is found to be
between 1.30 and 1.63 $(\times10^{45}g$ $cm^2)$. Moreover, the transition
density at the crust-core boundary is shown to be in the narrow range of
$\rho_t=[0.091-0.093](fm^{-3})$.


title: Remarks on the Origin of Path Integration: Einstein and Feynman

abstract:
  I offer some historical comments about the origins of Feynman's path integral
approach, as an alternative approach to standard quantum mechanics. Looking at
the interaction between Einstein and Feynman, which was mediated by Feynman's
thesis supervisor John Wheeler, it is argued that, contrary to what one might
expect, the significance of the interaction between Einstein and Feynman
pertained to a critique of classical field theory, rather than to a direct
critique of quantum mechanics itself. Nevertheless, the critical perspective on
classical field theory became a motivation and point of departure for Feynman's
space-time approach to non-relativistic quantum mechanics.


title: Episturmian words: a survey

abstract:
  In this paper, we survey the rich theory of infinite episturmian words which
generalize to any finite alphabet, in a rather resembling way, the well-known
family of Sturmian words on two letters. After recalling definitions and basic
properties, we consider episturmian morphisms that allow for a deeper study of
these words. Some properties of factors are described, including factor
complexity, palindromes, fractional powers, frequencies, and return words. We
also consider lexicographical properties of episturmian words, as well as their
connection to the balance property, and related notions such as finite
episturmian words, Arnoux-Rauzy sequences, and "episkew words" that generalize
the skew words of Morse and Hedlund.


title: Palindromic Richness

abstract:
  In this paper, we study combinatorial and structural properties of a new
class of finite and infinite words that are 'rich' in palindromes in the utmost
sense. A characteristic property of so-called "rich words" is that all complete
returns to any palindromic factor are themselves palindromes. These words
encompass the well-known episturmian words, originally introduced by the second
author together with X. Droubay and G. Pirillo in 2001. Other examples of rich
words have appeared in many different contexts. Here we present the first
unified approach to the study of this intriguing family of words.
  Amongst our main results, we give an explicit description of the periodic
rich infinite words and show that the recurrent balanced rich infinite words
coincide with the balanced episturmian words. We also consider two wider
classes of infinite words, namely "weakly rich words" and almost rich words
(both strictly contain all rich words, but neither one is contained in the
other). In particular, we classify all recurrent balanced weakly rich words. As
a consequence, we show that any such word on at least three letters is
necessarily episturmian; hence weakly rich words obey Fraenkel's conjecture.
Likewise, we prove that a certain class of almost rich words obeys Fraenkel's
conjecture by showing that the recurrent balanced ones are episturmian or
contain at least two distinct letters with the same frequency.
  Lastly, we study the action of morphisms on (almost) rich words with
particular interest in morphisms that preserve (almost) richness. Such
morphisms belong to the class of "P-morphisms" that was introduced by A. Hof,
O. Knill, and B. Simon in 1995.


title: The Mobius Band and the Mobius Foliation

abstract:
  This article presents some computations for a new topological invariant for
foliations introduced some years ago by the author using techniques from
noncommutative geometry, in particular the pairing between K-Theory and cyclic
cohomology. The motivation came from theoretical physics, more specifically
from flat vector bundles, in physics terminology from potentials which are pure
gauge.


title:
Computational approach to the emergence and evolution of language -
  evolutionary naming game model

abstract:
  Computational modelling with multi-agent systems is becoming an important
technique of studying language evolution. We present a brief introduction into
this rapidly developing field, as well as our own contributions that include an
analysis of the evolutionary naming-game model. In this model communicating
agents, that try to establish a common vocabulary, are equipped with an
evolutionarily selected learning ability. Such a coupling of biological and
linguistic ingredients results in an abrupt transition: upon a small change of
the model control parameter a poorly communicating group of linguistically
unskilled agents transforms into almost perfectly communicating group with
large learning abilities. Genetic imprinting of the learning abilities proceeds
via Baldwin effect: initially unskilled communicating agents learn a language
and that creates a niche in which there is an evolutionary pressure for the
increase of learning ability. Under the assumption that communication intensity
increases continuously with finite speed, the transition is split into several
transition-like changes. It shows that the speed of cultural changes, that sets
an additional characteristic timescale, might be yet another factor affecting
the evolution of language. In our opinion, this model shows that linguistic and
biological processes have a strong influence on each other and this effect
certainly has contributed to an explosive development of our species.


title:
Statistical Analysis of Crossed Undulator for Polarization Control in a
  SASE FEL

abstract:
  There is a growing interest in producing intense, coherent x-ray radiation
with an adjustable and arbitrary polarization state. In this paper, we study
the crossed undulator scheme (K.-J. Kim, Nucl. Instrum. Methods A {\bf 445},
329 (2000)) for rapid polarization control in a self-amplified spontaneous
emission (SASE) free electron laser (FEL). Because a SASE source is a
temporally chaotic light, we perform a statistical analysis on the state of
polarization using FEL theory and simulations. We show that by adding a small
phase shifter and a short (about 1.3 times the FEL power gain length),
$90^\circ$ rotated planar undulator after the main SASE planar undulator, one
can obtain circularly polarized light -- with over 80% polarization -- near the
FEL saturation.


title:
Spectral split in prompt supernova neutrino burst: Analytic three-flavor
  treatment

abstract:
  The prompt nu_e burst from a core-collapse supernova (SN) is subject to both
matter-induced flavor conversions and strong neutrino-neutrino refractive
effects. For the lowest-mass progenitors, leading to O-Ne-Mg core SNe, the
matter density profile can be so shallow that the usual MSW matter effects
occur within the dense-neutrino region close to the neutrino sphere. In this
case a ``split'' occurs in the emerging spectrum, i.e., the nu_e flavor
survival probability shows a step-like feature. We explain this feature
analytically as a ``MSW prepared spectral split.'' In a three-flavor treatment,
the step-like feature actually consists of two narrowly spaced splits. They are
determined by two combinations of flavor-lepton numbers that are conserved
under collective oscillations.


title: Wrapping Interactions and the Konishi Operator

abstract:
  We present a calculation of the four-loop anomalous dimension of the SU(2)
sector Konishi operator in N=4 SYM, as an example of "wrapping" corrections to
the known result for long operators. We use the known dilatation operator at
four loops acting on long operator, and just calculate those diagrams which are
affected by the change from operator length L > 4 to L = 4. We find that the
answer involves a Zeta[5], so it has trancendentality degree five. Our result
differs from previous proposals and calculations. We also discuss some ideas
for extending this analysis to determine finite size corrections for operators
of arbitrary length in the SU(2) sector.


title: Mini Little Higgs and Dark Matter

abstract:
  We construct a little Higgs model with the most minimal extension of the
standard model gauge group by an extra U(1) gauge symmetry. For specific charge
assignments of scalars, an approximate U(3) global symmetry appears in the
cutoff-squared scalar mass terms generated from gauge bosons at one-loop level.
Hence, the Higgs boson, identified as a pseudo-Goldstone boson of the broken
global symmetry, has its mass radiatively protected up to scales of 5-10 TeV.
In this model, a Z2 symmetry, ensuring the two U(1) gauge groups to be
identical, also makes the extra massive neutral gauge boson stable and a viable
dark matter candidate with a promising prospect of direct detection.


title: Courant morphisms and moment maps

abstract:
  We study Hamiltonian spaces associated with pairs (E,A), where E is a Courant
algebroid and A\subset E is a Dirac structure. These spaces are defined in
terms of morphisms of Courant algebroids with suitable compatibility
conditions. Several of their properties are discussed, including a reduction
procedure. This set-up encompasses familiar moment map theories, such as
group-valued moment maps, and it provides an intrinsic approach from which
different geometrical descriptions of moment maps can be naturally derived. As
an application, we discuss the relationship between quasi-Poisson and
presymplectic groupoids.


title: Entangled coherent states under dissipation

abstract:
  We study the evolution of entangled coherent states of the two quantized
electromagnetic fields under dissipation. Characteristic time scales for the
decay of the negativity are found in the case of large values of the phase
space distance among the states of each mode. We also study how the
entanglement emerges among the reservoirs.


title:
Quantitative Constraints on the Transport Properties of Hot Partonic
  Matter from Semi-Inclusive Single High Transverse Momentum Pion Suppression
  in Au+Au collisions at sqrt(s_NN) = 200 GeV

abstract:
  The PHENIX experiment has measured the suppression of semi-inclusive single
high transverse momentum pi^0's in Au+Au collisions at sqrt(s_NN) = 200 GeV.
The present understanding of this suppression is in terms of energy-loss of the
parent (fragmenting) parton in a dense color-charge medium. We have performed a
quantitative comparison between various parton energy-loss models and our
experimental data. The statistical point-to-point uncorrelated as well as
correlated systematic uncertainties are taken into account in the comparison.
We detail this methodology and the resulting constraint on the model
parameters, such as the initial color-charge density dN^g/dy, the medium
transport coefficient <q^hat>, or the initial energy-loss parameter epsilon_0.
We find that high transverse momentum pi^0 suppression in Au+Au collisions has
sufficient precision to constrain these model dependent parameters at the +/1
20%-25% (one standard deviation) level. These constraints include only the
experimental uncertainties, and further studies are needed to compute the
corresponding theoretical uncertainties.


title: Generalized Chern-Simons Terms and Chiral Anomalies in N=1 Supersymmetry

abstract:
  The gauging of axionic, Stueckelberg-type, shift symmetries with generalized
Chern-Simons terms and the Green-Schwarz mechanism of anomaly cancellation has
recently been studied in the context of certain string compactifications and
with regard to the phenomenology of unusual variants of Z'-bosons. In this
talk, following recent work with De Rydt, Rosseel, Schmidt and Van Proeyen, I
summarize how such theories can be reconciled with global and local N=1
supersymmetry. Two simple consistency conditions are shown to encode strong
constraints on the allowed anomalies for different types of gauge groups.


title: Generalised perturbation equations in bouncing cosmologies

abstract:
  We consider linear perturbation equations for long-wavelength scalar metric
perturbations in generalised gravity, applicable to non-singular cosmological
models including a bounce from collapse to expansion in the very early
universe. We present the general form for the perturbation equations which
follows from requiring that the inhomogeneous universe on large scales obeys
the same local equations as the homogeneous Friedmann-Robertson-Walker
background cosmology (the separate universes approach). In a
pseudo-longitudinal gauge this becomes a homogeneous second-order differential
equation for adiabatic perturbations, which reduces to the usual equation for
the longitudinal gauge metric perturbation in general relativity with vanishing
anisotropic stress. As an application we show that the scale-invariant spectrum
of perturbations in the longitudinal gauge generated during an ekpyrotic
collapse are not transferred to the growing mode of adiabatic density
perturbations in the expanding phase in a simple bounce model.


title: The shallow phase of X-ray afterglows

abstract:
  We propose that the flat decay phase in the first 100-10,000 seconds of the
X-ray light curve of Gamma Ray Bursts can be interpreted as prolonged activity
of the central engine, producing shells of decreasing bulk Lorentz factors
Gamma. The internal dissipation of these late shells produces a continuous and
smooth emission, usually dominant in X-rays and sometimes in the optical. When
Gamma of the late shells is larger than 1/theta_j, where theta_j is the jet
opening angle, we see only a portion of the emitting surface. Eventually, Gamma
becomes smaller than 1/theta_j, and the entire emitting surface is visible.
When Gamma=1/theta_j there is a break in the light curve, and the plateau ends.
During the plateau phase, we see the sum of the "late-prompt" emission (due to
late internal dissipation), and the "real afterglow" emission (due to external
shocks). A variety of different optical and X-ray light curves is possible,
explaining why the X-ray and the optical light curves often do not track each
other, and why they often do not have simultaneous breaks.


title:
Continuous theory of ferroelectric states in ultrathin films with real
  electrodes

abstract:
  According to a continuous medium theory, in very thin ferroelectric films
with real metallic electrodes (or dead layers near the electrodes) the domain
structure reduces to sinusoidal distribution of ferroelectric polarization.
Such a sinusoidal structure was considered in 1980s for para-ferroelectric
phase transition in a capacitor with dead layers near electrode. We give a
review of this theory and its further development for the case of real metallic
electrodes. The goal of the general theory is to consistently interpret the
experimental data in very thin films with real metallic electrodes. This is
illustrated on a recent experimental data for 5-30 nm BaTiO3 films with
SrRuO3/SrTiO3 electrodes. The screening length by real metallic electrodes is
very small small (<1A), but it has a profound effect on ferroelectric
properties and its phase behavior. This general theory also allows to formulate
the important open problems and show paths towards their solution. In
particular, this is a problem of finding parameters of the system, which can
sustain the ferroelectric memory over a desired lifetime.


title:
Metallicities and Physical Conditions in Star-forming Galaxies at
  z~1.0-1.5

abstract:
  We present a study of the mass-metallicity (M-Z) relation and H II region
physical conditions in a sample of 20 star-forming galaxies at 1.0<z<1.5 drawn
from the DEEP2 Galaxy Redshift Survey. Our analysis indicates that the zero
point of the M-Z relationship evolves with redshift, in the sense that galaxies
at fixed stellar mass become more metal-rich at lower redshift. Measurements of
[O III]/H-beta and [N II]/H-alpha emission-line ratios show that, on average,
objects in the DEEP2 1.0<z<1.5 sample are significantly offset from the
excitation sequence observed in nearby H II regions and SDSS emission-line
galaxies. In order to fully understand the causes of this offset, which is also
observed in z~2 star-forming galaxies, we examine in detail the small fraction
of SDSS galaxies that have similar diagnostic ratios to those of the DEEP2
sample. Some of these galaxies indicate evidence for AGN and/or shock activity,
which may give rise to their unusual line ratios, and contribute to Balmer
emission lines at the level of ~20%. Others indicate no evidence for AGN or
shock excitation, yet are characterized by higher electron densities and
temperatures, and therefore, interstellar gas pressures, than typical SDSS
star-forming galaxies of similar stellar mass. These anomalous objects also
have higher concentrations and star-formation rate surface densities, which are
directly connected to higher interstellar pressure. Higher star-formation rate
surface densities, interstellar pressures, and HII region ionization parameters
may also be common at high-redshift. These effects must be taken into account
when using strong-line indicators to understand the evolution of heavy elements
in galaxies. When such effects are included, the inferred evolution of the M-Z
relation out to z~2 is more significant than previous estimates. (abridged)


title:
Self-isospectrality, special supersymmetry, and their effect on the band
  structure

abstract:
  We study a planar model of a non-relativistic electron in periodic magnetic
and electric fields that produce a 1D crystal for two spin components separated
by a half-period spacing. We fit the fields to create a self-isospectral pair
of finite-gap associated Lame equations shifted for a half-period, and show
that the system obtained is characterized by a new type of supersymmetry. It is
a special nonlinear supersymmetry generated by three commuting integrals of
motion, related to the parity-odd operator of the associated Lax pair, that
coherently reflects the band structure and all its peculiarities. In the
infinite period limit it provides an unusual picture of supersymmetry breaking.

categories: hep-th cond-mat.other math-ph math.MP nlin.SI quant-ph


title:
Rapid Rotation, Active Nests of Convection and Global-scale Flows in
  Solar-like Stars

abstract:
  In the solar convection zone, rotation couples with intensely turbulent
convection to build global-scale flows of differential rotation and meridional
circulation. Our sun must have rotated more rapidly in its past, as is
suggested by observations of many rapidly rotating young solar-type stars. Here
we explore the effects of more rapid rotation on the patterns of convection in
such stars and the global-scale flows which are self-consistently established.
The convection in these systems is richly time dependent and in our most
rapidly rotating suns a striking pattern of spatially localized convection
emerges. Convection near the equator in these systems is dominated by one or
two patches of locally enhanced convection, with nearly quiescent streaming
flow in between at the highest rotation rates. These active nests of convection
maintain a strong differential rotation despite their small size. The structure
of differential rotation is similar in all of our more rapidly rotating suns,
with fast equators and slower poles. We find that the total shear in
differential rotation, as measured by latitudinal angular velocity contrast,
Delta_Omega, increases with more rapid rotation while the relative shear,
Delta_Omega/Omega, decreases. In contrast, at more rapid rotation the
meridional circulations decrease in both energy and peak velocities and break
into multiple cells of circulation in both radius and latitude.


title: Downsizing by Shutdown in Red Galaxies

abstract:
  We address the origin of the `downsizing' of elliptical galaxies, according
to which the stars in more massive galaxies formed earlier and over a shorter
period than those in less massive galaxies. We show that this could be the
natural result of a shutdown of star formation in dark matter haloes above a
critical mass of 10^12MSun. This is demonstrated using a semianalytic
simulation of galaxy formation within the standard hierarchical scenario of
structure formation. The assumed threshold mass is motivated by the prediction
of stable shock heating above this mass and the finding that such a shutdown
reproduces the observed distribution of galaxies in luminosity and colour.The
shutdown at a critical halo mass introduces a characteristic stellar mass for
the transition of galaxies into the `red sequence' of the galaxy
colour-magnitude diagram. Central galaxies of haloes that are more massive
today have reached this mass earlier and can therefore grow further along the
red sequence by dry mergers, ending up more massive and containing older stars.
Small galaxies formed in haloes below the critical mass can shutdown late, when
they fall into haloes above the critical mass and become satellites. While our
semianalytic simulation that incorporates an explicit shutdown reproduces
downsizing as inferred from the stellar ages of ellipticals, we explain why it
is much harder to detect downsizing using the mass functions of different
galaxy types.


title: A combined space discrete algorithm with a Taylor series by time for CFD

abstract:
  The first order by time partial differential equations are used as models in
applications such as fluid flow, heat transfer, solid deformation,
electromagnetic waves, and others. In this paper we propose the new numerical
method to solve a class of initial-boundary value problems for the PDEs using
one of the known space discrete numerical schemes and a Taylor series expansion
by time. Normally a second order discretization by space is applied while a
first order by time is satisfactory. Nevertheless, in a number of different
problems, discretization both by temporal and by spatial variables is needed of
highest orders, which complicates numerical solution, in some cases
dramatically. Therefore it is difficult to apply the same numerical methods for
the solution of some PDE arrays if their parameters are varying in a wide range
so that in some of them different numerical schemes by time fit the best for
precise numerical solution. The Taylor series based solution strategy for the
non-stationary PDEs in CFD simulations has been proposed here that attempts to
optimise the computation time and fidelity of the numerical solution.


title:
Assessing the Predictive Power of Galaxy Formation Models with the
  Rest-Frame Optical Luminosity Functions at 2.0<z<3.3

abstract:
  We compare recently measured rest-frame V-band luminosity functions (LFs) of
galaxies at redshifts 2.0<z<3.3 to predictions of semianalytic models by De
Lucia & Blaizot and Bower et al. and hydrodynamic simulations by Dave et al.
The models succeed for some luminosity and redshift ranges and fail for others.
A notable success is that the Bower et al. model provides a good match to the
observed LF at z~3. However, all models predict an increase with time of the
rest-frame V-band luminosity density, whereas the observations show a decrease.
The models also have difficulty matching the observed rest-frame colors of
galaxies. In all models the luminosity density of red galaxies increases
sharply from z~3 to z~2.2, whereas it is approximately constant in the
observations. Conversely, in the models the luminosity density of blue galaxies
is approximately constant, whereas it decreases in the observations. These
discrepancies cannot be entirely remedied by changing the treatment of dust and
suggest that current models do not yet provide an adequate description of
galaxy formation and evolution since z~3.


title:
Analyzing the Topology Types arising in a Family of Algebraic Curves
  Depending On Two Parameters

abstract:
  Given the implicit equation $F(x,y,t,s)$ of a family of algebraic plane
curves depending on the parameters $t,s$, we provide an algorithm for studying
the topology types arising in the family. For this purpose, the algorithm
computes a finite partition of the parameter space so that the topology type of
the family stays invariant over each element of the partition. The ideas
contained in the paper can be seen as a generalization of the ideas in
\cite{JGRS}, where the problem is solved for families of algebraic curves
depending on one parameter, to the two-parameters case.


title:
Possibility of Precise Measurement of the Cosmological Power Spectrum
  With a Dedicated 21cm Survey After Reionization

abstract:
  Measurements of the 21cm line emission by residual cosmic hydrogen after
reionization can be used to trace the power spectrum of density perturbations
through a significant fraction of the observable volume of the Universe. We
show that a dedicated 21cm observatory coule probe a number of independent
modes that is two orders of magnitude larger than currently available, and
enable a cosmic-variance limited detection of the signature of a neutrino mass
~0.05eV. The evolution of the linear growth factor with redshift could also
constrain exotic theories of gravity or dark energy to an unprecedented
precision.


title:
New insights into the stellar content and physical conditions of
  star-forming galaxies at z = 2-3 from spectral modelling

abstract:
  We have used extensive libraries of model and empirical galaxy spectra
(assembled respectively from the population synthesis code of Bruzual and
Charlot and the fourth data release of the Sloan Digital Sky Survey) to
interpret some puzzling features seen in the spectra of high redshift
star-forming galaxies. We show that a stellar He II 1640 emission line,
produced in the expanding atmospheres of Of and Wolf-Rayet stars, should be
detectable with an equivalent width of 0.5-1.5AA in the integrated spectra of
star-forming galaxies, provided the metallicity is greater than about half
solar. Our models reproduce the strength of the He II 1640 line measured in the
spectra of Lyman break galaxies for established values of their metallicities.
With better empirical calibrations in local galaxies, this spectral feature has
the potential of becoming a useful diagnostic of massive star winds at high, as
well as low, redshifts.
  We also uncover a relationship in SDSS galaxies between their location in the
[O III]/Hb vs. [N II]/Ha diagnostic diagram (the BPT diagram) and their excess
specific star formation rate relative to galaxies of similar mass. We infer
that an elevated ionisation parameter U is at the root of this effect, and
propose that this is also the cause of the offset of high redshift star-forming
galaxies in the BPT diagram compared to local ones. We further speculate that
higher electron densities and escape fractions of hydrogen ionising photons may
be the factors responsible for the systematically higher values of U in the H
II regions of high redshift galaxies. The impact of such differences on
abundance determinations from strong nebular lines are considered and found to
be relatively minor.


title:
Discovering the top partners at the LHC using same-sign dilepton final
  states

abstract:
  A natural, non-supersymmetric solution to the hierarchy problem generically
requires fermionic partners of the top quark with masses not much heavier than
500 GeV. We study the pair production and detection at the LHC of the top
partners with electric charge Q=5/3 (T_{5/3}) and Q=-1/3 (B), that are
predicted in models where the Higgs is a pseudo-Goldstone boson. The exotic
T_{5/3} fermion, in particular, is the distinct prediction of a LR custodial
parity invariance of the electroweak symmetry breaking sector. Both kinds of
new fermions decay to Wt, leading to a t\bar{t}WW final state. We focus on the
golden channel with two same-sign leptons, and show that a discovery could come
with less than 100 pb^{-1} (less than 20 fb^{-1}) of integrated luminosity for
masses M=500 GeV (M=1TeV). In the case of the T_{5/3}, we present a simple
strategy for its reconstruction in the fully hadronic decay chain. Although no
full mass reconstruction is possible for the B, we still find that the
same-sign dilepton channel offers the best chances of discovery compared to
other previous searches that used final states with one or two opposite-sign
leptons, and hence suffered from the large t\bar{t} background. Our analysis
also directly applies to the search of 4th generation b' quarks.


title: R Coronae Borealis stars in the Galactic Bulge discovered by EROS-2

abstract:
  Rare types of variable star may give unique insight into short-lived stages
of stellar evolution. The systematic monitoring of millions of stars and
advanced light curve analysis techniques of microlensing surveys make them
ideal for discovering also such rare variable stars. One example is the R
Coronae Borealis (RCB) stars, a rare type of evolved carbon-rich supergiant. We
have conducted a systematic search of the EROS-2 database for the Galactic
catalogue Bulge and spiral arms to find Galactic RCB stars. The light curves of
$\sim$100 million stars, monitored for 6.7 years (from July 1996 to February
2003), have been analysed to search for the main signature of RCB stars, large
and rapid drops in luminosity. Follow-up spectroscopy has been used to confirm
the photometric candidates. We have discovered 14 new RCB stars, all in the
direction of the Galactic Bulge, bringing the total number of confirmed
Galactic RCB stars to about 51. After reddening correction, the colours and
absolute magnitudes of at least 9 of the stars are similar to those of
Magellanic RCB stars. This suggests that these stars are in fact located in the
Galactic Bulge, making them the first RCB stars discovered in the Bulge. The
localisation of the 5 remaining RCBs is more uncertain: 4 are either located
behind the Bulge at an estimated maximum distance of 14 kpc or have an unusual
thick circumstellar shell; the other is a DY Per RCB which may be located in
the Bulge, even if it is fainter than the known Magellanic DY Per. From the
small scale height found using the 9 new Bulge RCBs, $61<h^{RCB}_{Bulge}<246$
pc (95% C.L.), we conclude that the RCB stars follow a disk-like distribution
inside the Bulge.


title: Curious Variables Experiment (CURVE). Three Periodicities of BF Ara

abstract:
  We report CCD photometry of the dwarf nova BF Ara throughout fifteen
consecutive nights in quiescence. Light curve in this interval is dominated by
a large amplitude around 0.8 mag modulation consisting two periods. Higher
amplitude signal is characterized by period of 0.082159(4) days, which was
increasing at the rate of dotP/Psh = 3.8(3)* 10^{-5}. Weaker and stable signal
has period of 0.084176(21) days. Knowing the superhump period of BF Ara
determined by Kato et al. (2003) and equal to 0.08797(1) days, the first
modulation is interpreted as quiescent negative superhump arising from
retrograde precesion of titled accretion disk and the latter one as an orbital
period of the binary. The respective period excess and defect are epsilon_+ =
4.51% +/- 0.03% and epsilon_- = -2.44% +/- 0.02%. Thus BF Ara is yet another
in-the-gap nova with mass ratio q of around 0.21.


title:
Anisotropy of Electrical Transport and Superconductivity in Metal Chains
  of Nb2Se3

abstract:
  In this work we have shown bulk superconductivity and studied the anisotropy
in both the normal and superconducting states in quasi-1D conductor Nb2Se3.
Electron - electron Umklapp scattering dominates electronic transport along the
direction of Nb metal chains as well as perpendicular to it. The
superconducting state is rather anisotropic with possible multi - band
features.


title:
Continuing dynamic assimilation of the inner region data in
  hydrodynamics modelling: Optimization approach

abstract:
  In meteorological and oceanological studies the classical approach for
finding the numerical solution of the regional model consists in formulating
and solving the Cauchy-Dirichlet problem. The related boundary conditions are
obtained by linear interpolation of data available on a coarse grid (global
data), to the boundary of regional model. Errors, in boundary conditions,
appearing owing to linear interpolation may lead to increasing errors in
numerical solution during integration. The methods developed to reduce these
errors deal with continuous dynamic assimilation of known global data available
inside the regional domain. Essentially, this assimilation procedure performs a
nudging of large-scale component of regional model solution to large-scale
global data component by introducing the relaxation forcing terms into the
regional model equations. As a result, the obtained solution is not a valid
numerical solution of the original regional model. In this work we propose the
optimization approach which is free from the above-mentioned shortcoming. The
formulation of the joint problem of finding the regional model solution and
data assimilation, as a PDE-constrained optimization problem, gives the
possibility to obtain the exact numerical solution of the regional model. Three
simple model examples (ODE Burgers equation, Rossby-Oboukhov equation,
Korteweg-de Vries equation) were considered in this paper. The result of
performed numerical experiments indicates that the optimization approach can
significantly improve the precision of the sought numerical solution, even in
the cases in which the solution of Cauchy-Dirichlet problem is very sensitive
to the errors in the boundary condition.