title: Superconductivity in a Hubbard-Froehlich Model and in cuprates

abstract:
  Using the variational Monte-Carlo method we find that a relatively weak
long-range electron-phonon interaction induces a d-wave superconducting state
of doped Mott-Hubbard insulators and/or strongly-correlated metals with a
condensation energy significantly larger than can be obtained with Coulomb
repulsion only. Moreover, the superconductivity is shown to exist for infinite
on-site Coulomb repulsion, removing the requirement for additional mechanisms
such as spin fluctuations to mediate d-wave superconductivity. We argue that
the superconducting state is robust with respect to a more intricate choice of
the trial function and that the true origin of high-temperature
superconductivity lies in a proper combination of strong electron-electron
correlations with poorly screened Froehlich electron-phonon interaction.


title:
Pulsations in the atmosphere of the rapidly oscillating Ap star 10
  Aquilae

abstract:
  The rapidly oscillating Ap (roAp) star 10 Aql shows one of the lowest
photometric pulsation amplitudes and is characterized by an unusual
spectroscopic pulsational behavior compared to other roAp stars. More than 1000
spectra were taken during 7 nights over a time span of 21 days with
high-resolution spectrographs at the 8-m ESO VLT and 3.6-m TNG telescopes
giving access to radial velocity variations of about 150 lines from different
chemical species. A comparison of pulsation signatures in lines formed at
different atmospheric heights allowed us to resolve the vertical structure of
individual pulsation modes in 10 Aql which is the first time for a
multiperiodic roAp star. The inferred propagation of pulsation waves in 10 Aql
is qualitatively similar to other roAp stars: pulsation amplitudes become
measurable in the layers where Y and Eu are concentrated, increase in layers
where the Halpha core is formed, reach a maximum of 200-300 m/s in the layers
probed by Ce, Sm, Dy lines and then decrease to 20-50 m/s in the layers where
NdIII and PrIII lines are formed. A unique pulsation feature of 10 Aql is a
second pulsation maximum indicated by TbIII lines which form in the uppermost
atmospheric layers and oscillate with amplitudes of up to 350 m/s. The dramatic
decline of pulsations in the atmospheric layers probed by the strong PrIII and
NdIII lines accounts for the apparent peculiarity of 10 Aql when compared to
other roAp stars. The phase-amplitude diagrams and bisector measurements of the
NdIII 5102 A line reveal a rapid change of phase and amplitude with height for
all three main pulsation modes, indicating the presence of a pulsation node in
the stellar atmosphere. (abridged)


title: Quantum Phase Diagram of Bosons in Optical Lattices

abstract:
  We work out two different analytical methods for calculating the boundary of
the Mott-insulator-superfluid (MI-SF) quantum phase transition for scalar
bosons in cubic optical lattices of arbitrary dimension at zero temperature
which improve upon the seminal mean-field result. The first one is a
variational method, which is inspired by variational perturbation theory,
whereas the second one is based on the field-theoretic concept of effective
potential. Within both analytical approaches we achieve a considerable
improvement of the location of the MI-SF quantum phase transition for the first
Mott lobe in excellent agreement with recent numerical results from Quantum
Monte-Carlo simulations in two and three dimensions. Thus, our analytical
results for the whole quantum phase diagram can be regarded as being
essentially exact for all practical purposes.


title:
Self-consistent calculations within the Green's function method
  including particle-phonon coupling and the single-particle continuum

abstract:
  The Green's function method in the \emph{Quasiparticle Time Blocking
Approximation} is applied to nuclear excitations in $^{132}$Sn and $^{208}$Pb.
The calculations are performed self-consistently using a Skyrme interaction.
The method combines the conventional RPA with an exact single-particle
continuum treatment and considers in a consistent way the particle-phonon
coupling. We reproduce not only the experimental values of low- and high-lying
collective states but we also obtain fair agreement with the data of
non-collective low-lying states that are strongly influenced by the
particle-phonon coupling.


title: Strict abnormal extremals in nonholonomic and kinematic control systems

abstract:
  In optimal control problems, there exist different kinds of extremals, that
is, curves candidates to be solution: abnormal, normal and strictly abnormal.
The key point for this classification is how those extremals depend on the cost
function. We focus on control systems such as nonholonomic control mechanical
systems and the associated kinematic systems as long as they are equivalent.
  With all this in mind, first we study conditions to relate an optimal control
problem for the mechanical system with another one for the associated kinematic
system. Then, Pontryagin's Maximum Principle will be used to connect the
abnormal extremals of both optimal control problems.
  An example is given to glimpse what the abnormal solutions for kinematic
systems become when they are considered as extremals to the optimal control
problem for the corresponding nonholonomic mechanical systems.


title: The very massive binary NGC3603-A1

abstract:
  Using VLT/SINFONI, we have obtained repeated AO-assisted, NIR spectroscopy of
the three central WN6ha stars in the core of the very young (~1 Myr), massive
and dense Galactic cluster NGC3603. One of these stars, NGC3603-A1, is a known
3.77-day, double-eclipsing binary, while another one, NGC3603-C, is one of the
brightest X-ray sources among all known Galactic WR stars, which usually is a
strong indication for binarity. Our study reveals that star C is indeed an
8.9-day binary, although only the WN6ha component is visible in our spectra;
therefore we temporarily classify star C as an SB1 system. A1, on the other
hand, is found to consist of two emission-line stars of similar, but not
necessarily of identical spectral type, which can be followed over most the
orbit. Using radial velocities for both components and the previously known
inclination angle of the system, we are able to derive absolute masses for both
stars in A1. We find M_1 = (116 \pm 31) Mo for the primary and M_2 = (89 \pm
16) Mo for the secondary component of A1. While uncertainties are large, A1 is
intrinsically half a magnitude brighter than WR20a, the current record holder
with 83 and 82 Mo, respectively; therefore, it is likely that the primary in A1
is indeed the most massive star weighed so far.


title: Torsional rigidity of submanifolds with controlled geometry

abstract:
  We prove explicit upper and lower bounds for the torsional rigidity of
extrinsic domains of submanifolds P^m with controlled radial mean curvature in
ambient Riemannian manifolds N^n with a pole p and with sectional curvatures
bounded from above and from below, respectively. These bounds are given in
terms of the torsional rigidities of corresponding Schwarz symmetrizations of
the domains in warped product model spaces. Our main results are obtained using
methods from previously established isoperimetric inequalities, as found in
e.g. [MP4] and [MP5]. As in [MP4] we also characterize the geometry of those
situations in which the bounds for the torsional rigidity are actually attained
and study the behavior at infinity of the so-called geometric average of the
mean exit time for Brownian motion.


title: Quark Schwinger-Dyson equation in temporal Euclidean space

abstract:
  We present an elementary nonperturbative method to obtain Green's functions
(GFs) for timelike momenta. We assume there are no singularities in the first
and third quadrants of the complex plane of space momentum components and
perform a 3d analogue of Wick rotation. This procedure defines Greens functions
in a timelike Euclidean space. As an example we consider the quark propagator
in QCD. While for weak coupling, this method is obviously equivalent to
perturbation theory, for a realistic QCD coupling a complex part of the quark
mass and renormalization wave function has been spontaneously generated even
below the standard perturbative threshold. Therefore, our method favors a
confinement mechanism based on the lack of real poles.


title: New Young Brown Dwarfs in the Orion Molecular Cloud 2/3 Region

abstract:
  Forty new low mass members with spectral types ranging from M4-M9 have been
confirmed in the Orion Molecular Cloud 2/3 region. Through deep, I, z', J, H, K
photometry of a 20' x 20' field in OMC 2/3, we selected brown dwarf candidates
for follow-up spectroscopy. Low resolution far-red and near-infrared spectra
were obtained for the candidates, and 19 young brown dwarfs in the OMC 2/3
region are confirmed. They exhibit spectral types of M6.5-M9, corresponding to
approximate masses of 0.075-0.015 M_solar using the evolutionary models of
Baraffe et al. (1998). At least one of these bona fide young brown dwarfs has
strong Halpha emission, indicating that it is actively accreting. In addition,
we confirm 21 new low mass members with spectral types of M4-M6, corresponding
to approximate masses of 0.35-0.10 M_solar in OMC 2/3. By comparing pre-main
sequence tracks to the positions of the members in the H-R diagram, we find
that most of the brown dwarfs are less than 1 Myr, but find a number of low
mass stars with inferred ages greater than 3 Myr. The discrepancy in the
stellar and substellar ages is due to our selection of only low luminosity
sources; however, the presence of such objects implies the presence of an age
spread in the OMC 2/3 region. We discuss possible reasons for this apparent age
spread.


title: Identification of a Marginal Fermi-Liquid in Itinerant Ferromagnet CoS2

abstract:
  We report specific heat, resistivity and susceptibility measurements at
different temperatures, magnetic fields, and pressures to provide solid
evidence of CoS2 being a marginal Fermi liquid. The presence of a tricritical
point in the phase diagram of the system provides an opportunity to test the
spin fluctuation theory with a high limit of accuracy. A magnetic field
suppresses the amplitude of the spin fluctuations and recovers conventional
Fermi liquid behavior, connecting both states continuously.


title:
Unital Quantum Channels - Convex Structure and Revivals of Birkhoff's
  Theorem

abstract:
  The set of doubly-stochastic quantum channels and its subset of mixtures of
unitaries are investigated. We provide a detailed analysis of their structure
together with computable criteria for the separation of the two sets. When
applied to O(d)-covariant channels this leads to a complete characterization
and reveals a remarkable feature: instances of channels which are not in the
convex hull of unitaries can return to it when either taking finitely many
copies of them or supplementing with a completely depolarizing channel. In
these scenarios this implies that a channel whose noise initially resists any
environment-assisted attempt of correction can become perfectly correctable.


title: Fermions in Loop Quantum Cosmology and the Role of Parity

abstract:
  Fermions play a special role in homogeneous models of quantum cosmology
because the exclusion principle prevents them from forming sizable matter
contributions. They can thus describe the matter ingredients only truly
microscopically and it is not possible to avoid strong quantum regimes by
positing a large matter content. Moreover, possible parity violating effects
are important especially in loop quantum cosmology whose basic object is a
difference equation for the wave function of the universe defined on a discrete
space of triads. The two orientations of a triad are interchanged by a parity
transformation, which leaves the difference equation invariant for ordinary
matter. Here, we revisit and extend loop quantum cosmology by introducing
fermions and the gravitational torsion they imply, which renders the parity
issue non-trivial. A treatable locally rotationally symmetric Bianchi model is
introduced which clearly shows the role of parity. General wave functions
cannot be parity-even or odd, and parity violating effects in matter influence
the microscopic big bang transition which replaces the classical singularity in
loop quantum cosmology.


title:
Simplified Chaplygin Gas: Deriving $H_0$ From Ages of Old High Redshift
  Objects and Baryon Acoustic Oscillations

abstract:
  The discovery that the expansion of the Universe is accelerating is the most
challenging problem of modern cosmology. In the context of general relativity,
there are many dark energy candidates to explain the observed acceleration. In
this work we focus our attention on two kinds of simplified Chaplygin gas
cosmological accelerating models recently proposed in the literature. In the
first scenario, the simplified Chaplygin gas works like a Quintessence model
while in the second one, it plays the role of a Quartessence (an unification of
the dark sector). Firstly, in order to limit the free parameters of both
models, we discuss the age of high redshift objects with special emphasis to
the old quasar APM 08279+5255 at $z = 3.91$. The basic finding is that this old
high redshift object constrain severely the simplified Chaplygin cosmologies.
Secondly, through a joint analysis involving the baryon acoustic oscillations
(BAO) and a sample of old high redshift galaxies (OHRGs) we also estimate the
value of the Hubble parameter, $H_0$. Our approach suggests that the
combination of these two independent phenomena provides an interesting method
to constrain the Hubble constant.


title: Lensed Image Angles: New Statistical Evidence for Substructure

abstract:
  We introduce a novel statistical way of analyzing the projected mass
distribution in galaxy lenses based solely on the angular distribution of
images in quads around the lens center. The method requires the knowledge of
the lens center location, but the images' distances from the lens center are
not used at all. If the images of a quad are numbered in order of arrival time,
\theta_1 through \theta_4, and \theta_{ij} is the angle between images i and j,
then we define the 'bisector' plane whose axes are linear combinations of
\theta_{23} and \theta_{14}. The bisector plane of a given lens contains all
the quads produced by the lens. We show empirically that all two-fold symmetric
lenses with convex, i.e. non-wavy or petal-like isodensity contours are
identical in the bisector plane of their quads. We also study lenses with
twisting isodensity contours, lumpy substructure, etc. Our results suggest that
to reproduce the general characteristics of the observed quad population,
kpc-scale substructure must be a common feature of galaxy lenses.


title: Doubly periodic textile patterns

abstract:
  Knitted and woven textile structures are examples of doubly periodic
structures in a thickened plane made out of intertwining strands of yarn.
Factoring out the group of translation symmetries of such a structure gives
rise to a link diagram in a thickened torus. Such a diagram on a standard torus
is converted into a classical link by including two auxiliary components which
form the cores of the complementary solid tori. The resulting link, called a
kernel for the structure, is determined by a choice of generators u and v for
the group of symmetries.
  A normalised form of the multi-variable Alexander polynomial of a kernel is
used to provide polynomial invariants of the original structure which are
essentially independent of the choice of generators. It gives immediate
information about the existence of closed curves and other topological features
in the original textile structure. Because of its natural algebraic properties
under coverings we can recover the polynomial for kernels based on a proper
subgroup from the polynomial derived from the full symmetry group of the
structure. This enables two structures to be compared at similar scales, even
when one has a much smaller minimal repeating cell than the other.
  Examples of simple traditional structures are given, and their Alexander data
polynomials are presented to illustrate the techniques and results.


title:
Detectability of Pair Echos from Gamma-Ray Bursts and Intergalactic
  Magnetic Fields

abstract:
  High-energy emission from gamma-ray bursts (GRBs) can give rise to pair
echos, i.e. delayed inverse Compton emission from secondary $e^{\pm}$ pairs
produced in $\gamma-\gamma$ interactions with intergalactic background
radiation. We investigate the detectability of such emission with modern-day
gamma-ray telescopes. The spectra and light curves are calculated for a wide
range of parameters, applying the formalism recently developed by Ichiki et al.
The flux depends strongly on the unknown magnitude and coherence length of
intergalactic magnetic fields, and we delineate the range of field strength and
redshift that allow detectable echos. Relevant uncertainties such as the
high-energy cutoff of the primary gamma-ray spectrum and the intensity of the
cosmic infrared background are addressed. GLAST and MAGIC may be able to detect
pair echo emission from GRBs with redshift $\lesssim 1$ if the primary spectra
extend to $\sim 10 ~ {\rm TeV}$.


title:
Structural and angular dependence of coercivity and magnetic remanence
  of electrochemical ferromagnetic nanowires

abstract:
  A novel method for controlling nanowire magnetic properties and growth from
filling time profile is presented.
  The wires are grown with an electrodeposition method ("Template synthesis")
with a wide selection of pore diameters. We show that stray-fields presence in
ferromagnetic nanowires are entirely dependent on the nanowire diameter.
Besides a crossover effect in the reversal mechanism is observed with change in
diameter. In this work, theory and experiment agree and confirm that according
to the variety of hysteresis loop measured, about four ranges of values of pore
diameter control the orientation of nanowire magnetization easy axis with
respect to the geometrical axis.


title:
Dynamically generated heavy scalar fields in the Standard Model of
  Electroweak Interactions

abstract:
  It is shown that the gauge fixings of the Z and the W fields and three
scalars are via nonconserved axial-vector and charged vector currents of
massive fermions dynamically generated by fermion masses in the SM of EW
interactions. The top quark mass provides enough strength for this chiral
symmetry breaking. The masses of the three scalars are determined to be about
$10^{14}$ GeV. These scalars have negative probability. They are the
nonperturbative solutions of the SM. A new perturbation theory with dynamically
generated and fixed gauge fixings is constructed. The Faddeev-Popov procedure
is not invoked.


title: String topology on Gorenstein spaces

abstract:
  The purpose of this paper is to describe a general and simple setting for
defining $(g,p+q)$-string operations on a Poincar\'e duality space and more
generally on a Gorenstein space. Gorenstein spaces include Poincar\'e duality
spaces as well as classifying spaces or homotopy quotients of connected Lie
groups. Our presentation implies directly the homotopy invariance of each
$(g,p+q)$-string operation as well as it leads to explicit computations.


title:
Probing Intergalactic Magnetic Fields in the GLAST Era through Pair Echo
  Emission from TeV Blazars

abstract:
  More than a dozen blazars are known to be emitters of multi-TeV gamma rays,
often with strong and rapid flaring activity. By interacting with photons of
the cosmic microwave and infrared backgrounds, these gamma rays inevitably
produce electron-positron pairs, which in turn radiate secondary inverse
Compton gamma rays in the GeV-TeV range with a characteristic time delay that
depends on the properties of the intergalactic magnetic field (IGMF). For
sufficiently weak IGMF, such "pair echo" emission may be detectable by the
Gamma-ray Large Area Space Telescope (GLAST), providing valuable information on
the IGMF. We perform detailed calculations of the time-dependent spectra of
pair echos from flaring TeV blazars such as Mrk 501 and PKS 2155-304, taking
proper account of the echo geometry and other crucial effects. In some cases,
the presence of a weak but non-zero IGMF may enhance the detectability of
echos. We discuss the quantitative constraints that can be imposed on the IGMF
from GLAST observations, including the case of non-detections.


title: Effect of environmental spins on Landau-Zener transitions

abstract:
  Landau-Zener (LZ) transitions of a two-level system (e. g., electronic spin
in molecular magnets) coupled to one or many environmental spins (e. g.,
nuclear spins) are studied. For rather general interactions the LZ problem is
reduced to that of a Landau-Zener grid. It is shown analytically that
environmental spins initially in their ground state do not influence the
staying probability P. This changes if they are prepared in a statistical
ensemble. For a more specific model with environmental spins in a transverse
field, LZ transitions are studied in the case of well-separated resonances in
the LZ grid. The full evolution of the system is described as a succession of
elemenary transitions at avoided crossings and free evolution between them. If
the environmental spins are strongly coupled to the central spin, their effect
on P is weak. In other cases LZ transitions are strongly suppressed and P is
decreasing very slowly with the sweep-rate parameter epsilon ~ 1/v, v being the
energy sweep rate.


title:
Supervised functional classification: A theoretical remark and some
  comparisons

abstract:
  The problem of supervised classification (or discrimination) with functional
data is considered, with a special interest on the popular k-nearest neighbors
(k-NN) classifier. First, relying on a recent result by Cerou and Guyader
(2006), we prove the consistency of the k-NN classifier for functional data
whose distribution belongs to a broad family of Gaussian processes with
triangular covariance functions. Second, on a more practical side, we check the
behavior of the k-NN method when compared with a few other functional
classifiers. This is carried out through a small simulation study and the
analysis of several real functional data sets. While no global "uniform" winner
emerges from such comparisons, the overall performance of the k-NN method,
together with its sound intuitive motivation and relative simplicity, suggests
that it could represent a reasonable benchmark for the classification problem
with functional data.


title: CP Violation in the SUSY Seesaw: Leptogenesis and Low Energy

abstract:
  We suppose that the baryon asymmetry is produced by thermal leptogenesis
(with flavour effects), at temperatures $\sim 10^{9} - 10^{10}$ GeV, in the
supersymmetric seesaw with universal and real soft terms. The parameter space
is restricted by assuming that $l_\alpha \to l_\beta \gamma$ processes will be
seen in upcoming experiments. We study the sensitivity of the baryon asymmetry
to the phases of the lepton mixing matrix, and find that leptogenesis can work
for any value of the phases. We also estimate the contribution to the electric
dipole moment of the electron, arising from the seesaw, and find that it is
(just) beyond the sensitivity of next generation experiments ($\lsim 10^{-29}
e$ cm). The fourteen dimensional parameter space is efficiently explored with a
Monte Carlo Markov Chain, which concentrates on the regions of interest.


title:
A robust correlation between growth rate and amplitude of solar cycles:
  consequences for prediction methods

abstract:
  We consider the statistical relationship between the growth rate of activity
in the early phase of a solar cycle with its subsequent amplitude on the basis
of four datasets of global activity indices (Wolf sunspot number, group sunspot
number, sunspot area, and 10.7-cm radio flux). In all cases, a significant
correlation is found: stronger cycles tend to rise faster. Owing to the
overlapping of sunspot cycles, this correlation leads to an amplitude-dependent
shift of the solar minimum epoch. We show that this effect explains the
correlations underlying various so-called precursor methods for the prediction
of solar cycle amplitudes and also affects the prediction tool of Dikpati et
al. (2006) based upon a dynamo model. Inferences as to the nature of the solar
dynamo mechanism resulting from predictive schemes which (directly or
indirectly) use the timing of solar minima should therefore be treated with
caution.


title: Poisson equation for weak gravitational lensing

abstract:
  Using the Newman and Penrose spin coefficient (NP) formalism, we examine the
full Bianchi identities of general relativity in the context of gravitational
lensing, where the matter and space-time curvature are projected into a lens
plane perpendicular to the line of sight. From one component of the Bianchi
identity, we provide a rigorous, new derivation of a Poisson equation for the
projected matter density where the source term involves second derivatives of
the observed weak gravitational lensing shear. We also show that the other
components of the Bianchi identity reveal no new results. Numerical integration
of the Poisson equation in test cases shows an accurate mass map can be
constructed from the combination of a ground-based, wide-field image and a
Hubble Space Telescope image of the same system.


title:
Constraints on dark energy from baryon acoustic peak and galaxy cluster
  gas mass measurements

abstract:
  We use baryon acoustic peak measurements by Eisenstein et al. (2005) and
Percival et al. (2007a) and galaxy cluster gas mass fraction measurements of
Allen et al. (2008) to constrain parameters of three different dark energy
models. For time-independent dark energy, the Percival et al. (2007a)
constraints, which make use of the WMAP measurement of the apparent acoustic
horizon angle, most effectively constrain a cosmological parameter close to
spatial curvature and favor a close to spatially flat model. In a
spatially-flat model the Percival et al. (2007a) data less effectively
constrain time-varying dark energy. The joint baryon acoustic peak and galaxy
cluster gas mass constraints are consistent with but tighter than those derived
from other data. A time-independent cosmological constant in a spatially-flat
model provides a good fit to the joint data, but slowly-evolving dark energy
can not yet be ruled out.


title:
A New Approach for Reconstructing SUSY Particle Masses with a few
  fb^(-1) at the LHC

abstract:
  We describe a new cascade mass reconstruction approach to allow
reconstruction of SUSY particle masses in long cascades (five or more
particles) at the LHC with integrated luminosity as low as a few fb^(-1). This
approach is based on a consecutive use of the endpoint method, an event filter
and a combinatorial mass reconstruction method. The endpoint method gives a
preliminary estimate of light sparticle masses. An event filter combining the
maximum likelihood distributions for all events in the data sample allows
suppression of backgrounds and gives a preliminary estimate of heavy sparticle
masses. Finally, SUSY particle masses are reconstructed by a search for a
maximum of a combined likelihood function constructed for each possible
combination of five events in the data sample.
  SUSY data sample sets for the SU3 model point containing 80k events each were
generated, corresponding to an integrated luminosity of 4.2 fb^(-1). These
events were passed through the AcerDET detector simulator, which parametrized
the response of a detector. To demonstrate the stability and precision of the
approach five different 80k event data sets were considered. Masses were
reconstructed with a precision of about 10% for heavy sparticles and 10-20% for
light sparticles.


title: Melting of persistent double-stranded polymers

abstract:
  Motivated by recent DNA-pulling experiments, we revisit the Poland-Scheraga
model of melting a double-stranded polymer. We include distinct bending
rigidities for both the double-stranded segments, and the single-stranded
segments forming a bubble. There is also bending stiffness at the branch points
between the two segment types. The transfer matrix technique for single
persistent chains is generalized to describe the branching bubbles. Properties
of spherical harmonics are then exploited in truncating and numerically solving
the resulting transfer matrix. This allows efficient computation of phase
diagrams and force-extension curves (isotherms). While the main focus is on
exposition of the transfer matrix technique, we provide general arguments for a
reentrant melting transition in stiff double strands. Our theoretical approach
can also be extended to study polymers with bubbles of any number of strands,
with potential applications to molecules such as collagen.


title: Dictionary of LHC Signatures

abstract:
  We report on a plan to establish a "Dictionary of LHC Signatures", an
initiative that started at the WHEPPX workshop in January 2008. This study aims
towards the strategy on distinguishing of 3 classes of dark matter motivated
scenarios such as R-parity conserved supersymmetry, Little Higgs models with
T-parity conservation and Universal Extra Dimensions with KK-parity for generic
cases of their realization in wide range of the model space. Discriminating
signatures are tabulated and will need a further detailed analysis.


title:
One step synthesis of SmO1-xFxFeAs bulks with Tc = 54.6 K: High upper
  critical field and critical current density

abstract:
  A safe, simple and easily scaleable one-step sintering method is proposed to
fabricate newly discovered superconductors of SmO1-xFxFeAs. Superconducting
transition with the onset temperature of 54.6 K and high critical fields Hc2(0)
>=200 T were confirmed in SmO1-xFxFeAs with x = 0.3. At 5 K and self field,
critical current density Jc estimated from the magnetization hysteresis using
the whole sample size and the average particle size reached 8.5x10^3 and
1.2x10^6 A/cm^2, respectively. Moreover, the Jc exhibited a very weak
dependence on magnetic field. Microstructural characterizations revealed that
the whole sample Jc improvement could be achieved by either perfect texture or
optimization of fabrication process in this strongly-layered superconductor.
Our results clearly demonstrated that one-step synthesis technique is unique
and versatile and hence can be tailored easily for other rare earth derivatives
of REFeAsO superconductors.


title:
Cluster structure of functional networks estimated from high-resolution
  EEG data

abstract:
  We study the topological properties of functional connectivity patterns among
cortical areas in the frequency domain. The cortical networks were estimated
from high-resolution EEG recordings in a group of spinal cord injured patients
and in a group of healthy subjects, during the preparation of a limb movement.
We first evaluate global and local efficiency, as indicators of the structural
connectivity respectively at a global and local scale. Then, we use the Markov
Clustering method to analyse the division of the network into community
structures. The results indicate large differences between the injured patients
and the healthy subjects. In particular, the networks of spinal cord injured
patient exhibited a higher density of efficient clusters. In the Alpha (7-12
Hz) frequency band, the two observed largest communities were mainly composed
by the cingulate motor areas with the supplementary motor areas, and by the
pre-motor areas with the right primary motor area of the foot. This functional
separation strengthens the hypothesis of a compensative mechanism due to the
partial alteration in the primary motor areas because of the effects of the
spinal cord injury.


title:
Analytic Relations for Magnifications and Time Delays in Gravitational
  Lenses with Fold and Cusp Configurations

abstract:
  Gravitational lensing provides a unique and powerful probe of the mass
distributions of distant galaxies. Four-image lens systems with fold and cusp
configurations have two or three bright images near a critical point. Within
the framework of singularity theory, we derive analytic relations that are
satisfied for a light source that lies a small but finite distance from the
astroid caustic of a four-image lens. Using a perturbative expansion of the
image positions, we show that the time delay between the close pair of images
in a fold lens scales with the cube of the image separation, with a constant of
proportionality that depends on a particular third derivative of the lens
potential. We also apply our formalism to cusp lenses, where we develop
perturbative expressions for the image positions, magnifications and time
delays of the images in a cusp triplet. Some of these results were derived
previously for a source asymptotically close to a cusp point, but using a
simplified form of the lens equation whose validity may be in doubt for sources
that lie at astrophysically relevant distances from the caustic. Along with the
work of Keeton et al. (2005), this paper demonstrates that perturbation theory
plays an important role in theoretical lensing studies.


title:
A single-crystal source of path-polarization entangled photons at
  non-degenerate wavelengths

abstract:
  We demonstrate a bright, narrowband, compact, quasi-phase-matched
single-crystal source generating path-polarization-entangled photon pairs at
810 nm and 1550 nm at a maximum rate of 3 Mcounts/(s THz mW) after coupling to
single-mode fiber, and with two-photon interference visibility above 90%. While
the source can already be used to implement quantum communication protocols
such as quantum key distribution, this work is also instrumental for narrowband
applications such as entanglement transfer from photonic to atomic qubits, or
entanglement of photons from independent sources.


title:
MultiKulti Algorithm: Migrating the Most Different Genotypes in an
  Island Model

abstract:
  Migration policies in distributed evolutionary algorithms has not been an
active research area until recently. However, in the same way as operators have
an impact on performance, the choice of migrants is due to have an impact too.
In this paper we propose a new policy (named multikulti) for choosing the
individuals that are going to be sent to other nodes, based on
multiculturality: the individual sent should be as different as possible to the
receiving population. We have checked this policy on different discrete
optimization problems, and found that, in average or in median, this policy
outperforms classical ones like sending the best or a random individual.


title: 2-step nilpotent Lie groups arising from semisimple modules

abstract:
  Every finite dimensional real representation of a compact real semisimple Lie
algebra determines a metric 2-step nilpotent Lie algebra and a corresponding
simply connected metric 2-step nilpotent Lie group N. We study the differential
geometry of N using representation theory of the complexified complex
semisimple Lie algebra.


title:
Vibrational modes and low-temperature thermal properties of graphene and
  carbon nanotubes: A minimal force-constant model

abstract:
  We present a phenomenological force-constant model developed for the
description of lattice dynamics of sp2 hybridized carbon networks. Within this
model approach, we introduce a new set of parameters to calculate the phonon
dispersion of graphene by fitting the ab initio dispersion. Vibrational modes
of carbon nanotubes are obtained by folding the 2D dispersion of graphene and
applying special corrections for the low-frequency modes. Particular attention
is paid to the exact dispersion law of the acoustic modes, which determine the
low-frequency thermal properties and reveal quantum size effects in carbon
nanotubes. On the basis of the resulting phonon spectra, we calculate the
specific heat and the thermal conductance for several achiral nanotubes of
different diameter. Through the temperature dependence of the specific heat we
demonstrate that phonon spectra of carbon nanotubes show one-dimensional
behavior and that the phonon subbands are quantized at low temperatures.
Consequently, we prove the quantization of the phonon thermal conductance by
means of an analysis based on the Landauer theory of heat transport.


title: The Subaru/XMM-Newton Deep Survey (SXDS): III. X-Ray Data

abstract:
  We present the X-ray source catalog in the Subaru/XMM-Newton deep survey. A
continuous area of 1.14 deg^2 centered at R.A. = 02h18m and Dec. = -05d is
mapped by seven pointings with XMM-Newton covering the 0.2-10 keV band. From
the combined images of the EPIC pn and MOS cameras, we detect 866, 1114, 645,
and 136 sources with sensitivity limits of 6x10^{-16}, 8x10^{-16}, 3x10^{-15},
and 5x10^{-15} erg cm^{-2} s^{-1} in the 0.5-2, 0.5-4.5, 2-10, and 4.5-10 keV
bands, respectively, with detection likelihood >= 7 (corresponding to a
confidence level of 99.91%). The catalog consists of 1245 sources in total
including 32 extended-source candidates. The averaged log N-log S relations are
in good agreement with previous results, bridging the flux range between
Chandra deep surveys and brighter surveys. The log N-log S relations show
significant spatial variation among pointings on a scale of 0.2 deg^2.
Analyzing the auto correlation function, we detect significant clustering
signals from the 0.5-2 keV band sample, which can be fit with a power law form
(\theta/\theta_c)^{-0.8} with a correlation length of
\theta_c=5.9^{+1.0}_{-0.9} arcsec when the integral constraint term is
included. In the 2-10 keV band, however, the clustering is not significant with
a 90% upper limit of \theta_c < 1.5 arcsec.


title: Set Linear Algebra and Set Fuzzy Linear Algebra

abstract:
  In this book, the authors define the new notion of set vector spaces which is
the most generalized form of vector spaces. Set vector spaces make use of the
least number of algebraic operations, therefore, even a non-mathematician is
comfortable working with it. It is with the passage of time, that we can think
of set linear algebras as a paradigm shift from linear algebras. Here, the
authors have also given the fuzzy parallels of these new classes of set linear
algebras.
  This book is divided into seven chapters. The first chapter briefly recalls
some of the basic concepts in order to make this book self-contained. Chapter
two introduces the notion of set vector spaces which is the most generalized
concept of vector spaces. Set vector spaces lends itself to define new classes
of vector spaces like semigroup vector spaces and group vector spaces. These
are also generalization of vector spaces. The fuzzy analogue of these concepts
are given in Chapter three. In Chapter four, set vector spaces are generalized
to biset bivector spaces and not set vector spaces. This is done taking into
account the advanced information technology age in which we live. As
mathematicians, we have to realize that our computer-dominated world needs
special types of sets and algebraic structures. Set n-vector spaces and their
generalizations are carried out in Chapter five. Fuzzy n-set vector spaces are
introduced in the sixth chapter. The seventh chapter suggests more than three
hundred problems.


title: A note on K\"ahler-Ricci soliton

abstract:
  In this note we provide a proof of the following: Any compact KRS with
positive bisectional curvature is biholomorphic to the complex projective
space. As a corollary, we obtain an alternative proof of the Frankel conjecture
by using the K\"ahler-Ricci flow.


title:
Translocation of Polymers through Nanopores at Weak External Field,
  Direct Approach with Monte Carlo Simulations

abstract:
  I did off-lattice 3D Monte Carlo simulations for polymer translocation
through a narrow pore at low external field, trying to be as close to a direct
approach as possible. The process was found non equilibrium globally, but
dynamics of the monomers close to the pore (the fold) was found close to quasi
equilibrium. I observed a tension (or pressure) buildup near the pore, and
subdiffusion for the displacement of the middle monomer in the pore, as
reported in the literature. I did not find the distribution of the reaction
coordinate after some time of free diffusion predicted by the fractional
diffusion equation.


title:
Decoding Beta-Decay Systematics: A Global Statistical Model for Beta^-
  Halflives

abstract:
  Statistical modeling of nuclear data provides a novel approach to nuclear
systematics complementary to established theoretical and phenomenological
approaches based on quantum theory. Continuing previous studies in which global
statistical modeling is pursued within the general framework of machine
learning theory, we implement advances in training algorithms designed to
improved generalization, in application to the problem of reproducing and
predicting the halflives of nuclear ground states that decay 100% by the beta^-
mode. More specifically, fully-connected, multilayer feedforward artificial
neural network models are developed using the Levenberg-Marquardt optimization
algorithm together with Bayesian regularization and cross-validation. The
predictive performance of models emerging from extensive computer experiments
is compared with that of traditional microscopic and phenomenological models as
well as with the performance of other learning systems, including earlier
neural network models as well as the support vector machines recently applied
to the same problem. In discussing the results, emphasis is placed on
predictions for nuclei that are far from the stability line, and especially
those involved in the r-process nucleosynthesis. It is found that the new
statistical models can match or even surpass the predictive performance of
conventional models for beta-decay systematics and accordingly should provide a
valuable additional tool for exploring the expanding nuclear landscape.

categories: nucl-th astro-ph cond-mat.dis-nn cs.LG stat.ML


title: Conductance of a Conjugated Molecule with Carbon Nanotube Contacts

abstract:
  Calculations of the conductance of a carbon nanotube (CNT)-molecule-CNT
structure are in agreement with experimental measurements [1]. The features in
the transmission correspond directly to the features of the isolated molecular
orbitals. The HOMO provides conductance at low bias that is relatively
insensitive to the end groups of the cut CNTs, the cut angle, or the number of
molecular bridges. A molecular conformation change not directly in the path of
the carrier transport increases the resistance by over 2 orders of magnitude.
  [1] X. Guo, J. P. Small, J. E. Klare, Y. Wang, M. S. Purewal, I. W. Tam, B.
H. Hong, R. Caldwell, L. Huang, S. O'Brien, et al., Science 311, 356 (2006),
URL http://www.sciencemag.org/cgi/content/abstract/311/5759/356


title: NSV 13983: A New Dwarf Nova in the Period Gap

abstract:
  Aims. NSV 13983 is catalogued as a dwarf nova based on a reported outburst
from 2005. The system has not yet been studied spectroscopically. We attempt to
confirm its nature as a dwarf nova and determine its orbital period.
  Methods. We derive the orbital period by using time-resolved spectroscopic
data to measure radial velocities.
  Results. The average spectrum shows evidence that the system is a dwarf nova
in quiescence. The radial velocity curves derived from measurements of the
spectral lines H\alpha and H\beta, show a clear modulation with a period of
2.76 h. This places NSV 13983 below the upper edge of the gap in the period
distribution of cataclysmic variables, implying that it is the 14th dwarf nova
in the gap.


title:
Input Impedance and Gain of a Gigahertz Amplifier Using a DC SQUID in a
  Quarter Wave Resonator

abstract:
  Due to their superior noise performance, SQUIDs are an attractive alternative
to high electron mobility transistors for constructing ultra-low-noise
microwave amplifiers for cryogenic use. We describe the use of a lumped element
SQUID inductively coupled to a quarter wave resonator. The resonator acts as an
impedance transformer and also makes it possible for the first time to
accurately measure the input impedance and intrinsic microwave characteristics
of the SQUID. We present a model for input impedance and gain, compare it to
the measured scattering parameters, and describe how to use the model for the
systematic design of low-noise microwave amplifiers with a wide range of
performance characteristics.


title:
Signature of valley polarization in fractional flux periodicity of a
  graphene ring

abstract:
  We have studied the interplay of valley polarization and the Coulomb
interaction on the energy spectrum, persistent current, and optical absorption
of a graphene quantum ring. We show that the interaction has a dramatic effect
on the nature of the ground state as a function of the magnetic flux, and that
the absence of the exchange interaction in opposite valleys means that the
singlet-triplet degeneracy is not lifted for certain states. The additional
level crossings (fractional flux periodicity) due to the interaction directly
leads to extra steps in the persistent current and intricate structures in the
absorption spectrum that should be experimentally observable. By varying the
width of the ring, the nature of the ground state at zero field can be varied
as well and this is manifest in the measurable properties we discuss.


title:
A direct proof of Z-stability for AH algebras of bounded topological
  dimension

abstract:
  We prove that a unital simple approximately homogeneous (AH) C*-algebra with
no dimension growth absorbs the Jiang-Su algebra tensorially without appealing
to the classification theory of these algebras. Our main result continues to
hold under the slightly weaker hypothesis of exponentially slow dimension
growth.


title:
Generating sequences and Poincar\'e series for a finite set of plane
  divisorial valuations

abstract:
  Let $V$ be a finite set of divisorial valuations centered at a 2-dimensional
regular local ring $R$. In this paper we study its structure by means of the
semigroup of values, $S_V$, and the multi-index graded algebra defined by $V$,
$\gr_V R$. We prove that $S_V$ is finitely generated and we compute its minimal
set of generators following the study of reduced curve singularities. Moreover,
we prove a unique decomposition theorem for the elements of the semigroup.
  The comparison between valuations in $V$, the approximation of a reduced
plane curve singularity $C$ by families of sets $V^{(k)}$ of divisorial
valuations, and the relationship between the value semigroup of $C$ and the
semigroups of the sets $V^{(k)}$, allow us to obtain the (finite) minimal
generating sequences for $C$ as well as for $V$.
  We also analyze the structure of the homogeneous components of $\gr_V R$. The
study of their dimensions allows us to relate the Poincar\'e series for $V$ and
for a general curve $C$ of $V$. Since the last series coincides with the
Alexander polynomial of the singularity, we can deduce a formula of A'Campo
type for the Poincar\'e series of $V$. Moreover, the Poincar\'e series of $C$
could be seen as the limit of the series of $V^{(k)}$, $k\ge 0$.


title: Time-Varying Lense-Thirring System

abstract:
  We consider bound geodesic orbits of test masses in the exterior
gravitational field of a rotating astronomical source whose proper angular
momentum varies linearly with time. The linear perturbation approach of Lense
and Thirring is herein extended to the nonstationary case. In particular, we
investigate the instability of Lense-Thirring precessing orbits due to the slow
temporal variation of the gravitomagnetic field of the source.


title:
Ultrafast electron dynamics and cubic optical nonlinearity of free
  standing thin film of double walled carbon nanotubes

abstract:
  Ultrafast degenerate pump-probe experiments performed on a free standing film
of double walled carbon nanotubes near the first metallic transition energy of
outer tube show ultrafast ($97 fs$) photobleaching followed by a photo-induced
absorption with a slow relaxation of $1.8 ps$. Femtosecond closed and open
aperture z-scan experiments carried out at the same excitation energy show
saturation absorption and negative cubic nonlinearity. From these measurements,
real and imaginary part of the third order nonlinear susceptibility are
estimated to be Re($\chi^{(3)}) \sim -2.2 \times 10 ^{-9} esu$ and
Im($\chi^{(3)}) \sim 1.1 \times 10 ^{-11} esu$.


title: The X-ray Halo of Cen X-3

abstract:
  Using two Chandra observations we have derived estimates of the dust
distribution and distance to the eclipsing high mass X-ray binary (HMXB) Cen
X-3 using the energy-resolved dust-scattered X-ray halo. By comparing the
observed X-ray halos in 200 eV bands from 2-5 keV to the halo profiles
predicted by the Weingartner & Draine interstellar grain model, we find that
the vast majority (about 70%) of the dust along the line of sight to the system
is located within about 300 pc of the Sun, although the halo measurements are
insensitive to dust very close to the source. One of the Chandra observations
occurred during an egress from eclipse as the pulsar emerged from behind the
mass-donating primary. By comparing model halo light curves during this
transition to the halo measurements, a source distance of 5.7 +/- 1.5 kpc (68%
confidence level) is estimated, although we find this result depends on the
distribution of dust on very small scales. Nevertheless, this value is
marginally inconsistent with the commonly accepted distance to Cen X-3 of 8
kpc. We also find that the energy scaling of the scattering optical depth
predicted by the Weingartner & Draine interstellar grain model does not
accurately represent the results determined by X-ray halo studies of Cen X-3.
Relative to the model, there appears to be less scattering at low energies or
more scattering at high energies in Cen X-3.


title: Maximizing Sum Rates in Gaussian Interference-limited Channels

abstract:
  We study the problem of maximizing sum rates in a Gaussian
interference-limited channel that models multiuser communication in a CDMA
wireless network or DSL cable binder.
  Using tools from nonnegative irreducible matrix theory, in particular the
Perron-Frobenius Theorem and the Friedland-Karlin inequalities, we provide
insights into the structural property of optimal power allocation strategies
that maximize sum rates. Our approach is similar to the treatment of linear
models in mathematical economies, where interference is viewed in the context
of competition. We show that this maximum problem can be restated as a
maximization problem of a convex function on a closed convex set. We suggest
three algorithms to find the exact and approximate values of the optimal sum
rates. In particular, our algorithms exploit the eigenspace of specially
crafted nonnegative {\it interference matrices}, which, with the use of
standard optimization tools, can provide useful upper bounds and feasible
solutions to the nonconvex problem.


title:
The Radical Consequences of Realistic Satellite Orbits for the Heating
  and Implied Merger Histories of Galactic Disks

abstract:
  Previous models of galactic disk heating in interactions invoke restrictive
assumptions not necessarily valid in modern LCDM contexts: that satellites and
orbits are rigid and circular, with slow decay over many orbital times from
dynamical friction. This leads to a linear scaling of disk heating with
satellite mass: disk heights and velocity dispersions scale ~M_sat/M_disk. In
turn, observed disk thicknesses present strong constraints on merger histories:
the implication for the Milky Way is that <5% of its mass could come from
mergers since z~2, in conflict with cosmological predictions. More
realistically, satellites merge on nearly radial orbits, and once near the
disk, resonant interactions efficiently remove angular momentum while tidal
effects strip mass, leading to rapid merger/destruction in a couple of
free-fall plunges. Under these conditions the proper heating efficiency is
non-linear in mass ratio, ~(M_sat/M_disk)^2. We derive the scaling of disk
scale heights and velocity dispersions as a function of mass ratio and disk gas
content in this regime, and show this accurately describes the results of
simulations with proper 'live' halos and disks. Under realistic circumstances,
disk heating in minor mergers is suppressed by an order of magnitude relative
to expectations of previous models. We show that the Milky Way disk could have
absorbed ~5-10 1:10 mass-ratio mergers since z=2, in agreement with
cosmological models. These distinctions lead to dramatic differences in which
mass ratios are most important for disk heating and in the isophotal shapes of
disk+bulge systems.


title:
Microscopic diagonal entropy and its connection to basic thermodynamic
  relations

abstract:
  We define a diagonal entropy (d-entropy) for an arbitrary Hamiltonian system
as $S_d=-\sum_n \rho_{nn}\ln \rho_{nn}$ with the sum taken over the basis of
instantaneous energy states. In equilibrium this entropy coincides with the
conventional von Neumann entropy $S_n=-{\rm Tr}\, \rho\ln\rho$. However, in
contrast to $S_n$, the d-entropy is not conserved in time in closed Hamiltonian
systems. If the system is initially in stationary state then in accord with the
second law of thermodynamics the d-entropy can only increase or stay the same.
We also show that the d-entropy can be expressed through the energy
distribution function and thus it is measurable, at least in principle. Under
very generic assumptions of the locality of the Hamiltonian and
non-integrability the d-entropy becomes a unique function of the average energy
in large systems and automatically satisfies the fundamental thermodynamic
relation. This relation reduces to the first law of thermodynamics for
quasi-static processes. The d-entropy is also automatically conserved for
adiabatic processes. We illustrate our results with explicit examples and show
that $S_d$ behaves consistently with expectations from thermodynamics.


title: Obscuring Active Galactic Nuclei with Nuclear Starburst Disks

abstract:
  We assess the potential of nuclear starburst disks to obscure the
Seyfert-like AGN that dominate the hard X-ray background at z~1. Over 1200
starburst disk models, based on the theory developed by Thompson et al., are
calculated for five input parameters: the black hole mass, the radial size of
the starburst disk, the dust-to-gas ratio, the efficiency of angular momentum
transport in the disk, and the gas fraction at the outer disk radius. We find
that a large dust-to-gas ratio, a relatively small starburst disk, a
significant gas mass fraction, and efficient angular momentum transport are all
important to produce a starburst disk that can potentially obscure an AGN. The
typical maximum star-formation rate in the disks is ~10 solar masses per year.
Assuming no mass-loss due to outflows, the starburst disks feed gas onto the
black hole at rates sufficient to produce hard X-ray luminosities of
10^{43}-10^{44} erg s^{-1}. The starburst disks themselves should be detectable
at mid-infrared and radio wavelengths; at z=0.8, the predicted fluxes are ~1
mJy at 24microns and ~10-30 microJy at 1.4GHz. Thus, we predict a large
fraction of radio/X-ray matches in future deep radio surveys. The starburst
disks should be easily distinguished from AGN in future 100microns surveys by
Herschel with expected fluxes of ~5 mJy. Any AGN-obscuring starbursts will be
associated with hot dust, independent of AGN heating, resulting in observable
signatures for separating galactic and nuclear star-formation. Finally, because
of the competition between gas and star-formation, nuclear starbursts will be
associated with lower-luminosity AGN. Thus, this phenomenon is a natural
explanation for the observed decrease in the fraction of obscured AGN with
luminosity.


title: Landau-Yang Theorem and Decays of a Z' Boson into Two Z Bosons

abstract:
  We study the decay of a Z' boson into two Z bosons by extending the
Landau-Yang theorem to a parent particle decaying into two Z bosons. For a
spin-1 parent the theorem predicts: 1) there are only two possible couplings
and 2) the normalized differential cross-section depends on kinematics only
through a phase shift in the azimuthal angle between the two decay planes of
the Z boson. When the parent is a Z' the two possible couplings are
anomaly-induced and CP-violating, respectively. At the Large Hadron Collider
(LHC) effects of the two couplings could be disentangled when both Z bosons
decay leptonically.


title: Boson Hubbard model with weakly coupled Fermions

abstract:
  Using an imaginary-time path integral approach, we develop the perturbation
theory suited to the boson Hubbard model, and apply it to calculate the effects
of a dilute gas of spin-polarized fermions weakly interacting with the bosons.
The full theory captures both the static and the dynamic effects of the
fermions on the generic superfluid-insulator phase diagram. We find that, in a
homogenous system described by a single-band boson Hubbard Hamiltonian, the
intrinsic perturbative effect of the fermions is to generically suppress the
insulating lobes and to enhance the superfluid phase.


title: The Nature and Origin of Low-Redshift O VI Absorbers

abstract:
  The O VI ion observed in quasar absorption line spectra is the most
accessible tracer of the cosmic metal distribution in the low redshift (z<0.5)
intergalactic medium (IGM). We explore the nature and origin of O VI absorbers
using cosmological hydrodynamic simulations including galactic outflows. We
consider the effects of ionization background variations, non-equilibrium
ionization and cooling, uniform metallicity, and small-scale (sub-resolution)
turbulence. Our main results are 1) IGM O VI is predominantly photo-ionized
with T= 10^(4.2+/-0.2) K. A key reason for this is that O VI absorbers
preferentially trace over-enriched regions of the IGM at a given density, which
enhances metal-line cooling such that absorbers can cool within a Hubble time.
As such, O VI is not a good tracer of the WHIM. 2) The predicted O VI
properties fit observables only if sub-resolution turbulence is added. The
required turbulence increases with O VI absorber strength such that stronger
absorbers arise from more recent outflows with turbulence dissipating on the
order of a Hubble time. The amount of turbulence is consistent with other
examples of turbulence observed in the IGM and galactic halos. 3) Metals traced
by O VI and H I do not trace exactly the same baryons, but reside in the same
large-scale structure. Observed alignment statistics are reproduced in our
simulations. 4) Photo-ionized O VI traces gas in a variety of environments, and
is not directly associated with the nearest galaxy, though is typically nearest
to ~0.1L* galaxies. Weaker O VI components trace some of the oldest cosmic
metals. 5) Very strong absorbers are more likely to be collisionally ionized,
tracing more recent enrichment (<2 Gyr) within or near galactic halos.


title: AdS/CFT duality for non-relativistic field theory

abstract:
  We formulate a correspondence between non-relativistic conformal field
theories (NRCFTs) in d-1 spatial dimensions and gravitational theories in
AdS_{d+2} backgrounds with one compactified lightlike direction. The breaking
of the maximal SO(2,d+1) symmetry of AdS_{d+2} to the non-relativistic
conformal group arises from boundary conditions on bulk fields, without the
need to introduce non-vacuum sources of energy-momentum. As a check of the
proposal, we use the gravitational theory to reproduce the NRCFT state-operator
correspondence between scaling dimensions of primary operators and energy
eigenstates of the non-relativistic system placed in an external harmonic
potential.


title:
Spectral Index of the Diffuse Radio Background Measured From 100 to 200
  MHz

abstract:
  The mean absolute brightness temperature of the diffuse radio background was
measured as a function of frequency in a continuous band between 100 and 200
MHz over an effective solid angle of ~pi str at high Galactic latitude. A
spectral brightness temperature index of beta = 2.5 +/- 0.1 (alpha_s = 0.5) was
derived from the observations, where the error limits are 3-sigma and include
estimates of the instrumental systematics. Zenith drift scans with central
declinations of -26.5 degrees and spanning right ascensions 0 to 10 hours
yielded little variation in the mean spectral index. The mean absolute
brightness temperature at 150 MHz was found to reach a minimum of T = 237 +/-
10 K at a right ascension of 2.5 hours. Combining these measurements with those
of Haslam et al. 1982 yields a spectral index of beta = 2.52 +/- 0.04 between
150 and 408 MHz.


title:
Weinberg power counting and the quark determinant at small chemical
  potential

abstract:
  We construct an effective action for QCD by expanding the quark determinant
in powers of the chemical potential at finite temperature in the case of
massless quarks. To cut the infinite series we adopt the Weinberg power
counting criteria. We compute the minimal effective action (~p^4), expanding in
the external momentum, which implies the use of the hard thermal loop
approximation. Our main result is a gauge invariant expression for the phase
theta of the functional determinant in QCD, and recovers dimensional reduction
in the high-temperature limit. We compute, analytically, <theta^2> in the range
of p << 2 pi T, including perturbative and nonperturbative contributions, the
latter treated within the mean field approximation. Implications for lattice
simulations are briefly discussed.


title: On a possible quantum contribution to the red shift

abstract:
  We consider an effect generated by the nonexponential behavior of the
survival amplitude of an unstable state in the long time region: In 1957
Khalfin proved that this amplitude tends to zero as $t$ goes to the infinity
more slowly than any exponential function of $t$. This effect can be described
in terms of time-dependent decay rate $\gamma(t)$ and then the Khalfin result
means that this $\gamma(t)$ is not a constant for long times but that it tends
to zero as $t$ goes to the infinity. It appears that a similar conclusion can
be drawn for the energy of the unstable state for a large class of models of
unstable particles: This energy should be much smaller for suitably long times
$t$ than the energy of this state for $t$ of the order of the lifetime of the
considered state. Within a given model we show that the energy corrections in
the long ($t \to \infty$) and relatively short (lifetime of the state) time
regions, are different. It is shown that these corrections decrease to ${\cal
E} = {\cal E}_{min} < {\cal E}_{\phi}$ as $t \to \infty$, where ${\cal
E}_{\phi}$ is the energy of the system in the state $|\phi>$ measured at times
$t \sim \tau_{\phi}= \frac{\hbar}{\gamma}$. This is a purely quantum mechanical
effect. It is hypothesized that there is a possibility to detect this effect by
analyzing the spectra of distant astrophysical objects. The above property of
unstable states may influence the measured values of astrophysical and
cosmological parameters.


title: Rational convexity of non generic immersed lagrangian submanifolds

abstract:
  We prove that an immersed lagrangian submanifold in $\C^n$ with quadratic
self-tangencies is rationally convex. This generalizes former results for the
embedded and the immersed transversal cases.


title: Milky Way type galaxies in a LCDM cosmology

abstract:
  We analyse a sample of 52,000 Milky Way (MW) type galaxies drawn from the
publicly available galaxy catalogue of the Millennium Simulation with the aim
of studying statistically the differences and similarities of their properties
in comparison to our Galaxy. Model galaxies are chosen to lie in haloes with
maximum circular velocities in the range 200-250 km/seg and to have
bulge-to-disk ratios similar to that of the Milky Way. We find that model MW
galaxies formed quietly through the accretion of cold gas and small satellite
systems. Only 12 per cent of our model galaxies experienced a major merger
during their lifetime. Most of the stars formed in situ, with only about 15 per
cent of the final mass gathered through accretion. Supernovae and AGN feedback
play an important role in the evolution of these systems. At high redshifts,
when the potential wells of the MW progenitors are shallower, winds driven by
supernovae explosions blow out a large fraction of the gas and metals. As the
systems grow in mass, SN feedback effects decrease and AGN feedback takes over,
playing a more important role in the regulation of the star formation activity
at lower redshifts. Although model Milky Way galaxies have been selected to lie
in a narrow range of maximum circular velocities, they nevertheless exhibit a
significant dispersion in the final stellar masses and metallicities. Our
analysis suggests that this dispersion results from the different accretion
histories of the parent dark matter haloes. Statically, we also find evidences
to support the Milky Way as a typical Sb/Sc galaxy in the same mass range,
providing a suitable benchmark to constrain numerical models of galaxy
formation


title: QCD in the Spatial Axial Gauge

abstract:
  Canonical quantization of a gauge theory in the spatial axial gauge produces
an anisotropic Hamiltonian and matter particles surrounded by physically
unrealistic asymmetric electric or chromoelectric fields. We show how to
restore rotational symmetry for a nonabelian theory with a gauge fixing
condition $A^a_3=0$. We also discuss similarities between recovering isotropy
in the spatial axial gauge and finding gauge invariant quantities in the Weyl
gauge in both abelian and nonabelian field theories.


title: Monopoles and vortices in Yang-Mills plasma

abstract:
  We discuss the role of magnetic degrees of freedom in Yang-Mills plasma at
temperatures above and of order of the critical temperature Tc. While at zero
temperature the magnetic degrees of freedom are condensed and electric degrees
of freedom are confined, at the point of the phase transition both magnetic and
electric degrees of freedom are released into the thermal vacuum. This
phenomenon might explain the observed unusual properties of the plasma.


title: Quantitative Imaging of Single, Unstained Viruses with Coherent X-rays

abstract:
  Since Perutz, Kendrew and colleagues unveiled the structure of hemoglobin and
myoglobin based on X-ray diffraction analysis in the 1950s, X-ray
crystallography has become the primary methodology used to determine the 3D
structure of macromolecules. However, biological specimens such as cells,
organelles, viruses and many important macromolecules are difficult or
impossible to crystallize, and hence their structures are not accessible by
crystallography. Here we report, for the first time, the recording and
reconstruction of X-ray diffraction patterns from single, unstained viruses.
The structure of the viral capsid inside a virion was visualized. This work
opens the door for quantitative X-ray imaging of a broad range of specimens
from protein machineries, viruses and organelles to whole cells. Moreover, our
experiment is directly transferable to the use of X-ray free electron lasers,
and represents a major experimental milestone towards the X-ray imaging of
single macromolecules.


title:
Electrical Resistivity and Specific Heat of EuFe2As2 Single Crystals:
  Magnetic homologue of SrFe2As2

abstract:
  We have grown single crystals of EuFe2As2 and investigated its electrical
transport and thermodynamic properties. Electrical resistivity and specific
heat measurements clearly establish the intrinsic nature of magnetic phase
transitions at 20 K and 195 K. While the high temperature phase transition is
associated with the itinerant moment of Fe, the low temperature phase
transition is due to magnetic order of localized Eu-moments. Band structure
calculations point out a very close similarity of the electronic structure with
SrFe2As2. Magnetically, the Eu and Fe2As2 sublattice are nearly de-coupled.


title: Thompson's Group F and Uniformly Finite Homology

abstract:
  This paper demonstrates the uniformly finite homology developed by Block and
Weinberger and its relationship to amenable spaces via applications to the
Cayley graph of Thompson's Group F. In particular, a certain class of subgraph
of F is shown to be non-amenable. This shows that if F is amenable, these
subsets (which include every finitely generated submonoid of the positive
monoid of F) must necessarily have measure zero.


title: A Catalog of Multiplicity among Bright Stellar Systems

abstract:
  We consider the multiplicity of stellar systems with (combined) magnitude
brighter than 6.00 in Hipparcos magnitudes. We identify 4559 such bright
systems (including the Sun), and the frequencies of multiplicities 1, 2,..., 7
are found to be 2718, 1437, 285, 86, 20, 11 and 2. We discuss the
uncertainties, which are substantial. We also consider the distributions of
periods of orbits and sub-orbits. We note that for the even more restricted set
of 478 systems with V_H <= 4.00 the proportions of higher multiples up to
sextuple are progressively larger (213, 179, 54, 19, 8, 5), suggesting
substantial incompleteness in even the reasonably well-studied larger sample.
  This sample can be seen as relatively thoroughly studied for multiplicity,
and reasonably representative of stars more massive than the Sun. But the
restriction to V_H <= 6 means that our sample contains hardly any systems where
all components are low-mass main-sequence stars (K or M).
  Data on multiplicity is important as a constraint on (a) the star-formation
problem, (b) the problem of the evolution of the Galactic stellar population,
and (c) the interaction of dynamics and evolution through the effect of Kozai
cycles. We discuss these topics briefly.


title: New very massive stars in Cygnus OB2

abstract:
  The compact association Cygnus OB2 is known to contain a large population of
massive stars, but its total mass is currently a matter of debate. While recent
surveys have uncovered large numbers of OB stars in the area around Cyg OB2,
detailed study of the optically brightest among them suggests that most are not
part of the association. We observed an additional sample of optically faint OB
star candidates, with the aim of checking if more obscured candidates are
correspondingly more likely to be members of Cyg OB2. Low resolution spectra of
9 objects allow the rejection of one foreground star and the selection of four
O-type stars, which were later observed at higher resolution. In a subsequent
run, we observed three more stars in the classification region and three other
stars in the far red. We identify five (perhaps six) new evolved very massive
stars and three main sequence O-type stars, all of which are likely to be
members of Cyg OB2. The new findings allow a much better definition of the
upper HR diagram, suggesting an age ~2.5Myr for the association and hinting
that the O3-5 supergiants in the association are blue stragglers, either
younger or following a different evolutionary path from other cluster members.
Though the bulk of the early stars seems to belong to an (approximately)
single-age population, there is ample evidence for the presence of somewhat
older stars at the same distance. Our results suggest that, even though Cyg OB2
is unlikely to contain as many as 100 O-type stars, it is indeed substantially
more massive than was thought prior to recent infrared surveys.


title:
Exact results for Casimir interactions between dielectric bodies: The
  weak-coupling or van der Waals Limit

abstract:
  In earlier papers we have applied multiple scattering techniques to calculate
Casimir forces due to scalar fields between different bodies described by delta
function potentials. When the coupling to the potentials became weak,
closed-form results were obtained. We simplify this weak-coupling technique and
apply it to the case of tenuous dielectric bodies, in which case the method
involves the summation of van der Waals (Casimir-Polder) interactions. Once
again exact results for finite bodies can be obtained. We present closed
formulas describing the interaction between spheres and between cylinders, and
between an infinite plate and a retangular slab of finite size. For such a
slab, we consider the torque acting on it, and find non-trivial equilibrium
points can occur.


title:
Linear-T resistivity and change in Fermi surface at the pseudogap
  critical point of a high-Tc superconductor

abstract:
  A fundamental question of high-temperature superconductors is the nature of
the pseudogap phase which lies between the Mott insulator at zero doping and
the Fermi liquid at high doping p. Here we report on the behaviour of charge
carriers near the zero-temperature onset of that phase, namely at the critical
doping p* where the pseudogap temperature T* goes to zero, accessed by
investigating a material in which superconductivity can be fully suppressed by
a steady magnetic field. Just below p*, the normal-state resistivity and Hall
coefficient of La1.6-xNd0.4SrxCuO4 are found to rise simultaneously as the
temperature drops below T*, revealing a change in the Fermi surface with a
large associated drop in conductivity. At p*, the resistivity shows a linear
temperature dependence as T goes to zero, a typical signature of a quantum
critical point. These findings impose new constraints on the mechanisms
responsible for inelastic scattering and Fermi surface transformation in
theories of the pseudogap phase.


title: Stability of Distant Satellites of Giant Planets in the Solar System

abstract:
  We conduct a systematic survey of the regions in which distant satellites can
orbit stably around the four giant planets in the solar system, using orbital
integrations of up to $10^9$ yr. In contrast to previous investigations, we use
a grid of initial conditions on a surface of section to explore phase space
uniformly inside and outside the planet's Hill sphere (radius $r_{\rm H}$;
satellites outside the Hill sphere sometimes are also known as
quasi-satellites). Our confirmations and extensions of old results and new
findings include the following: (i) many prograde and retrograde satellites can
survive out to radii $\sim 0.5r_{\rm H}$ and $\sim 0.7r_{\rm H}$, respectively,
while some coplanar retrograde satellites of Jupiter and Neptune can survive
out to $\sim r_{\rm H}$; (ii) stable orbits do not exist within the Hill sphere
at high ecliptic inclinations when the semi-major axis is large enough that the
solar tide is the dominant non-Keplerian perturbation; (iii) there is a gap
between $\sim r_{\rm H}$ and $2r_{\rm H}$ in which no stable orbits exist; (iv)
at distances $\gtrsim 2r_{\rm H}$ stable satellite orbits exist around Jupiter,
Uranus and Neptune (but not Saturn). For Uranus and Neptune, in particular,
stable orbits are found at distances as large as $\sim 10r_{\rm H}$; (v) the
differences in the stable zones beyond the Hill sphere arise mainly from
differences in the planet/Sun mass ratio and perturbations from other planets;
in particular, the absence of stable satellites around Saturn is mainly due to
perturbations from Jupiter. It is therefore likely that satellites at distances
$\gtrsim 2r_{\rm H}$ could survive for the lifetime of the solar system around
Uranus, Neptune, and perhaps Jupiter.


title:
Near Infrared Monitoring of Ultracool Dwarfs: Prospects for Searching
  for Transiting Companions

abstract:
  Stars of late-M and L spectral types, collectively known as Ultracool Dwarfs
(UCDs), may be excellent targets for searches for extrasolar planets. Owing to
their small radii, the signal from an Earth-size planet transiting a UCD is, in
principle, readily detectable. We present results from a study designed to
evaluate the feasibility of using precise near infrared (NIR) photometry to
detect terrestrial extrasolar planets orbiting UCDs. We used the Peters
Automated InfRared Imaging TELescope (PAIRITEL) to observe a sample of 13 UCDs
over a period of 10 months. We consider several important systematic effects in
NIR differential photometry and develop techniques for generating photometry
with a precision of 0.01 mag and long-term stability. We simulate the planet
detection efficiency of an extended campaign to monitor a large sample of UCDs
with PAIRITEL. We find that both a targeted campaign with a single telescope
lasting several years and a campaign making use of a network of telescopes
distributed in longitude could provide significant sensitivity to terrestrial
planets orbiting UCDs, potentially in the habitable zone.


title: Resonance enhancement of magnetic Faraday rotation

abstract:
  Magnetic Faraday rotation is widely used in optics. In natural transparent
materials, this effect is very weak. One way to enhance it is to incorporate
the magnetic material into a periodic layered structure displaying a high-Q
resonance. One problem with such magneto-optical resonators is that a
significant enhancement of Faraday rotation is inevitably accompanied by strong
ellipticity of the transmitted light. More importantly, along with the Faraday
rotation, the resonator also enhances linear birefringence and absorption
associated with the magnetic material. The latter side effect can put severe
limitations on the device performance. From this perspective, we carry out a
comparative analysis of optical microcavity and a slow wave resonator. We show
that slow wave resonator has a fundamental advantage when it comes to Faraday
rotation enhancement in lossy magnetic materials.


title:
Testing long-term earthquake forecasts: likelihood methods and error
  diagrams

abstract:
  We propose a new method to test the effectiveness of a spatial point process
forecast based on a log-likelihood score for predicted point density and the
information gain for events that actually occurred in the test period. The
method largely avoids simulation use and allows us to calculate the information
score for each event or set of events as well as the standard error of each
forecast. As the number of predicted events increases, the score distribution
approaches the Gaussian law. The degree of its similarity to the Gaussian
distribution can be measured by the computed coefficients of skewness and
kurtosis. To display the forecasted point density and the point events, we use
an event concentration diagram or a variant of the Error Diagram (ED).
  We demonstrate the application of the method by using our long-term forecast
of seismicity in two western Pacific regions. We compare the ED for these
regions with simplified diagrams based on two-segment approximations. Since the
earthquakes in these regions are concentrated in narrow subduction belts, using
the forecast density as a template or baseline for the ED is a more convenient
display technique. We also show, using simulated event occurrence, that some
proposed criteria for measuring forecast effectiveness at EDs would be strongly
biased for a small event number.


title: Nuclear symmetry energy probed by neutron skin thickness of nuclei

abstract:
  We describe a relation between the symmetry energy coefficients c_sym(rho) of
nuclear matter and a_sym(A) of finite nuclei that accommodates other
correlations of nuclear properties with the low-density behavior of c_sym(rho).
Here we take advantage of this relation to explore the prospects for
constraining c_sym(rho) of systematic measurements of neutron skin sizes across
the mass table, using as example present data from antiprotonic atoms. The
found constraints from neutron skins are in harmony with the recent
determinations from reactions and giant resonances.


title: Simulating Cosmic Reionization

abstract:
  The Cosmic Dark Ages and the Epoch of Reionization constitute a crucial
missing link in our understanding of the evolution of the intergalactic medium
and the formation and evolution of galaxies. Due to the complex nature of this
global process it is best studied through large-scale numerical simulations.
This presents considerable computational challenges. The dominant contributors
of ionizing radiation were dwarf galaxies. These tiny galaxies must be resolved
in very large cosmological volumes in order to derive their clustering
properties and the corresponding observational signatures correctly, which
makes this one of the most challenging problems of numerical cosmology. We have
recently performed the largest and most detailed simulations of the formation
of early cosmological large-scale structures and their radiative feedback
leading to cosmic reionization. This was achieved by running extremely large
(up to 29 billion-particle) N-body simulations of the formation of the Cosmic
Web, with enough particles and sufficient force resolution to resolve all the
galactic halos with total masses larger than 10^8 Solar masses in computational
volumes of up to (163 Mpc)^3. These results were then post-processed by
propagating the ionizing radiation from all sources by using fast and accurate
ray-tracing radiative transfer method. Both of our codes are parallelized using
a combination of MPI and OpenMP and to this date have been run efficiently on
up to 2048 cores (N-body) and up to 10000 cores (radiative transfer) on the
newly-deployed Sun Constellation Linux Cluster at the Texas Advanced Computing
Center. In this paper we describe our codes, parallelization strategies,
scaling and some preliminary scientific results. (abridged)


title: Spread of infectious diseases through clustered populations

abstract:
  Networks of person-person contacts form the substrate along which infectious
diseases spread. Most network-based studies of the spread focus on the impact
of variations in degree (the number of contacts an individual has). However,
other effects such as clustering, variations in infectiousness or
susceptibility, or variations in closeness of contacts may play a significant
role. We develop analytic techniques to predict how these effects alter the
growth rate, probability, and size of epidemics and validate the predictions
with a realistic social network. We find that (for given degree distribution
and average transmissibility) clustering is the dominant factor controlling the
growth rate, heterogeneity in infectiousness is the dominant factor controlling
the probability of an epidemic, and heterogeneity in susceptibility is the
dominant factor controlling the size of an epidemic. Edge weights (measuring
closeness or duration of contacts) have impact only if correlations exist
between different edges. Combined, these effects can play a minor role in
reinforcing one another, with the impact of clustering largest when the
population is maximally heterogeneous or if the closer contacts are also
strongly clustered. Our most significant contribution is a systematic way to
address clustering in infectious disease models, and our results have a number
of implications for the design of interventions.


title: Detecting automorphic orbits in free groups

abstract:
  We present an effective algorithm for detecting automorphic orbits in free
groups, as well as a number of algorithmic improvements of train tracks for
free group automorphisms.


title: Learning Graph Matching

abstract:
  As a fundamental problem in pattern recognition, graph matching has
applications in a variety of fields, from computer vision to computational
biology. In graph matching, patterns are modeled as graphs and pattern
recognition amounts to finding a correspondence between the nodes of different
graphs. Many formulations of this problem can be cast in general as a quadratic
assignment problem, where a linear term in the objective function encodes node
compatibility and a quadratic term encodes edge compatibility. The main
research focus in this theme is about designing efficient algorithms for
approximately solving the quadratic assignment problem, since it is NP-hard. In
this paper we turn our attention to a different question: how to estimate
compatibility functions such that the solution of the resulting graph matching
problem best matches the expected solution that a human would manually provide.
We present a method for learning graph matching: the training examples are
pairs of graphs and the `labels' are matches between them. Our experimental
results reveal that learning can substantially improve the performance of
standard graph matching algorithms. In particular, we find that simple linear
assignment with such a learning scheme outperforms Graduated Assignment with
bistochastic normalisation, a state-of-the-art quadratic assignment relaxation
algorithm.


title: Multi-wavelength observations of jets at high and low X-ray luminosities

abstract:
  I shall briefly review the observational properties of radio-emitting jets
from Galactic X-ray binaries in relation with other wavebands: infrared,
optical and X-ray. Special attention is paid to recent results obtained with
the Spitzer Space Telescope on quiescent black holes as well as ultra-compact
neutron star X-ray binaries


title: Are superparamagnetic spins classical?

abstract:
  Effective giant spins of magnetic nanoparticles are considered classically in
the conventional theory of superparamagnetism based on the
Landau-Lifshitz-Langevin equation. However, microscopic calculations for a
large spin with uniaxial anisotropy, coupled to the lattice via the simplest
generic mechanism, show that the results of the conventional theory are not
reproduced in the limit S ->\infty. In particular, the prefactor Gamma_0 in the
Arrhenius escape rate over the barrier Gamma =Gamma_0 exp[-Delta U/(k_B T)] has
an anomalously large sensitivity to symmetry-breaking interactions such as
transverse field


title:
Extended 1D Method for Coherent Synchrotron Radiation including
  Shielding

abstract:
  Coherent Synchrotron Radiation can severely limit the performance of
accelerators designed for high brightness and short bunch length. Examples
include light sources based on ERLs or FELs, and bunch compressors for linear
colliders. In order to better simulate Coherent Synchrotron Radiation, the
established 1-dimensional formalism is extended to work at lower energies, at
shorter bunch lengths, and for an arbitrary configuration of multiple bends.
Wide vacuum chambers are simulated by means of vertical image charges. This
formalism has been implemented in the general beam dynamics code "Bmad" and its
results are here compared to analytical approximations, to numerical solutions
of the Maxwell equations, and to the simulation code "elegant".


title: Statistical Behaviour of the Leaves of Riccati Foliations

abstract:
  We introduce the geodesic flow on the leaves of a holomorphic foliation with
leaves of dimension 1 and hyperbolic, corresponding to the unique complete
metric of curvature -1 compatible with its conformal structure.
  We do these for the foliations associated to Riccati equations, which are the
projectivisation of the solutions of linear ordinary differential equations
over a finite Riemann surface of hyperbolic type S, and may be described by a
representation r:pi_1(S) -> GL(n,C). We give conditions under which the
foliated geodesic flow has a generic repellor-attractor statistical dynamics.
That is, there are measures m- and m+ such that for almost any initial
condition with respect to the Lebesgue measure class the statistical average of
the foliated geodesic flow converges for negative time to m- and for positive
time to m+ (i.e. m+ is the unique SRB-measure and its basin has total Lebesgue
measure). These measures are ergodic with respect to the foliated geodesic
flow. These measures are also invariant under a foliated horocycle flow and
they project to a harmonic measure for the Riccati foliation, which plays the
role of an attractor for the statistical behavior of the leaves of the
foliation.


title: Theoretical Overview of Hadronic Three-body B Decays

abstract:
  Charmless 3-body decays of B mesons are studied in a simple model based on
the factorization approach. We have identified two distinct sources of
nonresonant contributions: a small contribution from the tree transition and a
large source of the nonresonant signal in the matrix elements of scalar
densities, e.g., $<K\bar K|\bar ss|0>$, induced from the penguin transition.
This explains the dominance of the nonresonant background in $B\to KKK$ decays,
the sizable nonresonant fraction in $K^-\pi^+\pi^-$ and $\bar K^0\pi^+\pi^-$
modes and the smallness of nonresonant rates in $B\to \pi\pi\pi$ decays. The
seemingly huge discrepancy between BaBar and Belle for the nonresonant
contribution in the decay $B^-\to K^-\pi^+\pi^-$ is now relieved. We have
computed the resonant and nonresonant contributions to charmless 3-body decays
and determined the rates for the quasi-two-body decays $B\to VP$ and $B\to SP$.
Time-dependent CP asymmetries $\sin2\beta_{\rm eff}$ and $A_{CP}$ in
$K^+K^-K_S,K_SK_SK_S,K_S\pi^+\pi^-$ and $K_S\pi^0\pi^0$ modes are estimated.


title:
Robust photonic entanglement distribution via state-independent encoding
  onto decoherence-free subspace

abstract:
  Efficient and faithful implementation of quantum information tasks, e.g.,
quantum computing, quantum communication and quantum metrology, requires robust
and state-independent decoherence-suppressing measures to protect quantum
information carriers. Here we present an experimental demonstration of a robust
distribution scheme in which one photon of an entangled photon pair is
successfully encoded into and decoded from a decoherence-free subspace (DFS) by
a state-independent scheme. We achieved a high-fidelity distribution of the
entangled state over fibre communication channel, and also demonstrated that
the scheme is robust against fragility of the reference frame. The scheme,
thanks to its state-independence, is also applicable to multipartite case where
the photon to be distributed is entangled with many other photons. Such a
universal scheme opens the possibility of robust distribution of quantum
information among quantum communication and computing networks.


title:
Numerical simulation of excitation and propagation of helioseismic MHD
  waves: Effects of inclined magnetic field

abstract:
  Investigation of propagation, conversion, and scattering of MHD waves in the
Sun is very important for understanding the mechanisms of observed oscillations
and waves in sunspots and active regions. We have developed 3D linear MHD
numerical model to investigate influence of the magnetic field on excitation
and properties of the MHD waves. The results show that the magnetic field can
substantially change the properties of the surface gravity waves (f-mode), but
their influence on the acoustic-type waves (p-modes) is rather moderate.
Comparison our simulations with the time-distance helioseismology results from
SOHO/MDI shows that the travel time variations caused by the inclined magnetic
field do not exceed 25% of the observed amplitude even for strong fields of
1400-1900 G. This can be an indication that other effects (e.g. background
flows and non-uniform distribution of magnetic field) can contribute to the
observed travel time variations. The travel time variations caused by the wave
interaction with magnetic field are in phase with the observations for strong
fields of 1400-1900 G if Doppler velocities are taken at the height of 300 km
above the photosphere where plasma parameter beta<<1. The simulations show that
the travel times only weakly depend on the height of velocity observation. For
the photospheric level the travel times are systematically smaller on
approximately 0.12 min then for the hight of 300 km above the photosphere for
all studied ranges of the magnetic field strength and inclination angles. The
numerical MHD wave modeling and new data from the HMI instrument of the Solar
Dynamics Observatory will substantially advance our knowledge of the wave
interaction with strong magnetic fields on the Sun and improve the local
helioseismology diagnostics.


title: Hydrodynamic attraction of swimming microorganisms by surfaces

abstract:
  Cells swimming in confined environments are attracted by surfaces. We measure
the steady-state distribution of smooth-swimming bacteria (Escherichia coli)
between two glass plates. In agreement with earlier studies, we find a strong
increase of the cell concentration at the boundaries. We demonstrate
theoretically that hydrodynamic interactions of the swimming cells with solid
surfaces lead to their re-orientation in the direction parallel to the
surfaces, as well as their attraction by the closest wall. A model is derived
for the steady-state distribution of swimming cells, which compares favorably
with our measurements. We exploit our data to estimate the flagellar propulsive
force in swimming E. coli.


title: Incidence Rate of GRB-host-DLAs at High Redshift

abstract:
  We study the incidence rate of damped Ly-a systems associated with the host
galaxies of gamma-ray bursts (GRB-host-DLAs) as functions of neutral hydrogen
column density (N_HI) and projected star formation rate (SFR) using
cosmological SPH simulations. Assuming that the occurrence of GRBs is
correlated with the local SFR, we find that the median N_HI of GRB-host-DLAs
progressively shifts to lower N_HI values with increasing redshift, and the
incidence rate of GRB-host-DLAs with log N_HI > 21.0 decreases rapidly at z>=6.
Our results suggest that the likelihood of observing the signature of IGM
attenuation in GRB afterglows increases towards higher redshift, because it
will not be blocked by the red damping wing of DLAs in the GRB host galaxies.
This enhances the prospects of using high-redshift GRBs to probe the
reionization history of the Universe. The overall incidence rate of
GRB-host-DLAs decreases monotonically with increasing redshift, whereas that of
QSO-DLAs increases up to z=6. A measurement of the difference between the two
incidence rates would enable an estimation of the value of \eta_grb, which is
the mass fraction of stars that become GRBs for a given amount of star
formation. Our predictions can be tested by upcoming high-z GRB missions,
including JANUS (Joint Astrophysics Nascent Universe Scout) and SVOM (Space
multi-band Variable Object Monitor).


title:
Benchmarks for the New-Physics Search through CP Violation in B^0->pi^0
  K_S

abstract:
  Using isospin relations, we predict the Standard-Model correlation between
S_{pi^0 K_S}=(sin 2beta)_{pi^0 K_S} and A_{pi^0 K_S}, the mixing-induced and
direct CP asymmetries of B^0-> pi^0 K_S. The calculation uses flavour SU(3)
only to fix the isospin-3/2 amplitude through the B^\pm->pi^\pm pi^0 branching
ratio, and thus has a small irreducible theoretical error. It can reach percent
level precision thanks to expected future lattice-QCD progress for the
calculation of the relevant SU(3)-breaking form-factor ratio, and serves as a
benchmark for new-physics searches. We obtain an interesting picture in the
A_{pi^0 K_S} - S_{pi^0 K_S} plane, where the current experimental data show a
discrepancy with the Standard Model, and comment on the direct CP asymmetries
of B^0->pi^-K^+ and B^+ -> pi^0 K^+. A modified electroweak penguin with a
large new CP-violating phase can explain the discrepancy and allows us to
accommodate also the corresponding data for other b->s penguin-dominated
decays.


title: Optimal designs for mixed models in experiments based on ordered units

abstract:
  We consider experiments for comparing treatments using units that are ordered
linearly over time or space within blocks. In addition to the block effect, we
assume that a trend effect influences the response. The latter is modeled as a
smooth component plus a random term that captures departures from the smooth
trend. The model is flexible enough to cover a variety of situations; for
instance, most of the effects may be either random or fixed. The information
matrix for a design will be a function of several variance parameters. While
data will shed light on the values of these parameters, at the design stage,
they are unlikely to be known, so we suggest a maximin approach, in which a
minimal information matrix is maximized. We derive maximin universally optimal
designs and study their robustness. These designs are based on semibalanced
arrays. Special cases correspond to results available in the literature.


title:
Symplectic topology of SU(2)-representation varieties and link homology,
  I: Symplectic braid action and the first Chern class

abstract:
  There are some similarities between cohomology of SU(2)-representation
varieties of the fundamental group of some link complements and the Khovanov
homology of the links. We start here a program to explain a possible source of
these similarities. We introduce a symplectic manifold ${\mathscr M}$ with an
action of the braid group $B_{2n}$ preserving the symplectic structure. The
action allows to associate a Lagrangian submanifold of ${\mathscr M}$ to every
braid. The representation variety of a link can then be described as the
intersection of such Lagrangian submanifolds, given a braid presentation of the
link. We expect this to go some way in explaining the similarities mentioned
above.


title:
Finitely semisimple spherical categories and modular categories are
  self-dual

abstract:
  We show that every essentially small finitely semisimple k-linear additive
spherical category in which k=End(1) is a field, is equivalent to its dual over
the long canonical forgetful functor. This includes the special case of modular
categories. In order to prove this result, we show that the universal coend of
the spherical category with respect to the long forgetful functor is self-dual
as a Weak Hopf Algebra.


title: Fractional Quantum Hall Effect and vortex lattices

abstract:
  It is demonstrated that all observed fractions at moderate Landau level
fillings for the quantum Hall effect can be obtained without recourse to the
phenomenological concept of composite fermions. The possibility to have the
special topologically nontrivial many-electron wave functions is considered.
Their group classification indicates the special values of of electron density
in the ground states separated by a gap from excited states.