title: S-parameter and pseudo-Nambu-Goldstone boson mass from lattice QCD

abstract:
  We present a lattice calculation of $L_{10}$, one of the low energy constants
in Chiral Perturbation Theory, and the charged-neutral pion squared mass
splitting, using dynamical overlap fermion. Exact chiral symmetry of the
overlap fermion allows us to reliably extract these quantities from the
difference of the vacuum polarization functions for vector and axial-vector
currents. In the context of the technicolor models, these two quantities are
read as the $S$-parameter and the pseudo-Nambu-Goldstone boson mass
respectively, and play an important role in discriminating the models from
others. This calculation can serve as a feasibility study of the lattice
techniques for more general technicolor gauge theories.


title:
A cheap liquid additive from acetone for strong in-field Jc enhancement
  in MgB2 conductors

abstract:
  We report on significant flux pinning enhancement in MgB2/Fe tapes that has
been easily obtained by a simple and cheap route using acetone as both an
efficient ball-milling medium and liquid additive through the in situ method.
Results showed that the highly reactive C released from the decomposition of
the acetone substituted into B sites, accompanied by the grain refinement
effect due to the acetone doping. At 4.2 K, the transport Jc for the 5 wt %
acetone doped tapes sintered at 700C reached up to 2.4x10^4 A/cm^2 at 10 T,
which is even higher than that of the nano-C added samples heated at 900C.


title: Heat conduction in a 1D harmonic chain with three dimensional vibrations

abstract:
  We study vibrational energy transport in a quasi 1-D harmonic chain with both
longitudinal and transverse vibrations. We demonstrate via both numerical
simulation and theoretic analysis that for 1-D atomic chain connected by 3D
harmonic springs, the coefficient of heat conduction changes it continuously
with its lattice constant, indicating the qualitative difference from the
corresponding 1-D case where the coefficient is independent of the lattice
constant.


title:
Tunable frequency band-gap and pulse propagation in a strongly nonlinear
  diatomic chain

abstract:
  One-dimensional nonlinear phononic crystals have been assembled from periodic
diatomic chains of stainless steel cylinders alternated with
Polytetrafluoroethylene (PTFE) spheres. We report the presence of acoustic band
gaps in the dispersion relation of the linearized systems and study the
transformation of single and multiple pulses in linear, nonlinear and strongly
nonlinear regimes with numerical calculations and experiments. The limiting
frequencies of the band gap are within the audible frequency range (20-20,000
Hz) and can be tuned by varying the particle's material properties, mass and
initial compression. Pulses rapidly transform within very short distances from
the impacted end due to the influence of the band gap in the linear and in
nonlinear elastic chains. The effects of an in situ band gap created by a mean
dynamic compression are observed in the strongly nonlinear wave regime.


title: Resolving a Class I Protostar Binary System with Chandra

abstract:
  Using a sub-pixel event repositioning technique, we spatially resolved X-ray
emission from the infrared double system IRS 5 in the R Corona Australis
molecular cloud with ~0.8" separation. As far as we know, this result -
obtained from 8 Chandra archival observations between 2000 and 2005 - is the
first X-ray study of individual sources in a Class I protostar binary system
with a projected separation of less than 200 AU. We extracted light curves and
spectra of the individual sources using a two-dimensional image fitting method.
IRS 5a at the south, the source which was brighter in the near-infrared, showed
three X-ray flares lasting >20 ksec, reminiscent of X-ray flares from pre-main
sequence stars, while the northern source (IRS 5b) was quiescent in X-rays in
all the observations except for a 2005 August 9 observation with a factor of ~2
flux enhancement. In quiescence, these sources showed almost identical X-ray
spectra, with NH ~4e22 cm-2, kT ~2 keV, and log Lx ~30.2-3 ergs s-1. IRS 5a
showed plasma at temperatures up to kT ~5-6 keV during flares, while the column
density of IRS 5b increased by a factor of 2 during an observation on 2005
August 9. We discuss the evolutionary stages and variation of the X-ray
activity of these sources.


title: Centimeter Imaging of the R Coronae Australis Region

abstract:
  The R CrA region was observed in the 3.5 and 6.2 cm continuum with high
angular resolutions (0.6--1.7 arcseconds) using the Very Large Array. Archival
data sets were also analyzed for comparison, which provided angular resolutions
up to 0.3 arcseconds. A cluster of young stellar objects was detected, and a
rich array of star forming activities was revealed. IRS 7A showed an enhanced
outflow activity recently. The main peak of IRS 7A positionally coincides with
an X-ray source, which suggests that the X-ray emission is directly related to
the central protostar. The Class 0 source SMA 2 is associated with a double
radio source, B 9a and 9b, and seems to be driving two outflows. The B 9
complex is probably a multiple-protostar system. Both B 9a and 9b are
nonthermal radio sources with negative spectral indices. IRS 7B is a compact
radio source surrounded by an extended structure. The compact source
corresponds to the Class 0/I source SMA 1, and it is also closely associated
with an X-ray source, suggesting that magnetic activities start early in the
protostellar stage of evolution. The extended structure of IRS 7B may be a
bipolar outflow. IRS 5 was resolved into two sources with a separation of 0.9
arcseconds. Both IRS 5a and 5b display radio flares and X-ray emission,
suggesting that energetic magnetic processes are active in both members. The
month-scale active phase of IRS 5b implies that the flare activity must involve
large-scale magnetic fields. During the strong flare event of IRS 5b in 1998,
IRS 5a also showed an enhanced level of radio emission. This concurrent
activity suggests that IRS 5 may be an interacting young binary system, but the
interaction mechanism is unknown. Alternatively, what was seen in the radio
images could be a circumbinary halo.


title: Evolution equation of entanglement for general bipartite systems

abstract:
  We explore how entanglement of a general bipartite system evolves when one
subsystem undergoes the action of an arbitrary noisy channel. It is found that
the dynamics of entanglement for general bipartite systems under the influence
of such channel is determined by the channel's action on the maximally
entangled state, which includes as a special case the results for two-qubit
systems [Nature Physics 4, 99 (2008)]. In particular, for multi-qubit or
qubit-qudit systems, we get a general factorization law for evolution equation
of entanglement with one qubit being subject to a noisy channel. Our results
can help the experimental characterization of entanglement dynamics.


title: Optical Spectroscopic Observations of CI Camelopardalis

abstract:
  We present the results of optical spectroscopic observations of CI Cam.
Double-peaked profiles were simultaneously observed for the first time in the
hydrogen Balmer, He {\small I} $\lambda$6678 and Fe {\small II} lines during an
observational run in 2001 September. An intermediate viewing angle of the
circumstellar disk around the B[e] star is consistent with our data. A
significant decrease in the intensity of the H$\alpha$ and He {\small I} lines
in our 2004 September observations might have been the precursor of a line
outburst at the end of 2004. The remarkable increase in the intensity of all
lines and the decrease in visual brightness in 2005 might be due to the
environment filling with new material ejected during the outburst. The
environment of CI Cam is influenced by mass loss from the B[e] star and the
outburst of its compact companion.


title: Pressure-driven instabilities in astrophysical jets

abstract:
  Astrophysical jets are widely believed to be self-collimated by the
hoop-stress due to the azimuthal component of their magnetic field. However
this implies that the magnetic field is largely dominated by its azimuthal
component in the outer jet region. In the fusion context, it is well-known that
such configurations are highly unstable in static columns, leading to plasma
disruption. It has long been pointed out that a similar outcome may follow for
MHD jets, and the reasons preventing disruption are still not elucidated,
although some progress has been accomplished in the recent years.
  In these notes, I review the present status of this open problem for
pressure-driven instabilities, one of the two major sources of ideal MHD
instability in static columns (the other one being current-driven
instabilities).
  I first discuss in a heuristic way the origin of these instabilities.
Magnetic resonances and magnetic shear are introduced, and their role in
pressure-driven instabilities discussed in relation to Suydam's criterion. A
dispersion relation is derived for pressure-driven modes in the limit of large
azimuthal magnetic fields, which gives back the two criteria derived by
Kadomtsev for this instability. The growth rates of these instabilities are
expected to be short in comparison with the jet propagation time.
  What is known about the potential stabilizing role of the axial velocity of
jets is then reviewed. In particular, a nonlinear stabilization mechanism
recently identified in the fusion literature is discussed.
  Key words: Ideal MHD: stability, pressure-driven modes; Jets: stability


title: Time Variation of Rotation Measure Gradient in 3C 273 Jet

abstract:
  The existence of a gradient in the Faraday rotation measure (RM) of the
quasar 3C 273 jet is confirmed by follow-up observations. A gradient transverse
to the jet axis is seen for more than 20 mas in projected distance. Taking
account of the viewing angle, we estimate it to be more than 100 pc. Comparing
to the distribution of the RM in 1995, we detect a time variation of it at the
same distance from the core over 7 yr. We discuss the origin of the Faraday
rotation based on this rapid time variation. We rule out foreground media such
as a narrow-line region, and suggest a helical magnetic field in the sheath
region as the origin of this gradient of the RM.


title: Optical Spectroscopic Observations of Cyg X-1=HDE 226868

abstract:
  We present the results of the spectroscopic observations of HDE 226868, the
optical counterpart to the black hole X-ray binary Cyg X-1, from 2001 to 2006.
We analyze the variabilities of the two components in the complex H$\alpha$
line: one P-Cygni shaped component which follows the motion of the supergiant
and another emission component moving with an antiphase orbital motion relative
to the supergiant, which is attributed to a focused-stellar wind. The results
of KOREL disentangling of our spectra indicate that the focused stellar wind is
responsible for the major part of the variability of the H$\alpha$ emission
line. The emission of the supergiant component had a small difference between
the low/hard and high/soft states, while the focused wind component became
strong in the low/hard state and weak in the high/soft state. The wind is
nearly undisturbed by the X-ray photoionization during the low/hard state.
However, during the high/soft state, the X-rays from the compact object could
decelerate the line-driven wind and result in a high mass accretion rate, due
to the effect of the X-ray photoionization. The X-ray illuminating could also
change the temperature profile of the stellar wind and increase its
temperature, and thus decrease the H$\alpha$ emissivity of the wind, which
could explain the H$\alpha$ variabilities of Cyg X-1 during different X-ray
states.


title:
Multifrequency Polarimetry of the Nrao 140 Jet: Possible Detection of a
  Helical Magnetic Field and Constraints on its Pitch Angle

abstract:
  We present results from multifrequency polarimetry of NRAO 140 using the Very
Long Baseline Array. These observations allow us to reveal the distributions of
both the polarization position angle and the Faraday rotation measure (RM).
These distributions are powerful tools to discern the projected and
line-of-sight components of the magnetic field, respectively. We find a
systematic gradient in the RM distribution, with its sign being opposite at
either side of the jet with respect to the jet axis. The sign of the RM changes
only with the direction of the magnetic field component along the line of
sight, so this can be explained by the existence of helical magnetic components
associated with the jet itself. We derive two constraints for the pitch angle
of the helical magnetic field from the distributions of the RM and the
projected magnetic field; the RM distribution indicates that the helical fields
are tightly wound, while that of the projected magnetic field suggests they are
loosely wound around the jet axis. This inconsistency may be explained if the
Faraday rotator is not cospatial with theemitting region. Our results may point
toward a physical picture in which an ultra-relativistic jet (spine) with a
loosely wound helical magnetic field is surrounded by a sub-relativistic wind
layer (sheath) with a tightly wound helical magnetic field.


title:
Wavy-roughness effect to thermal explosion of materials with power-law
  thermal absorptivity in microannuli

abstract:
  We obtain the approximate solutions for the steady temperature profiles of
materials with a temperature-dependent thermal absorptivity inside a
microannulus with wavy-rough surfaces considering a quasilinear partial
differential equation by the boundary perturbation approach. We found the
critical Frank-Kamanestkii parameter will depend on the small amplitude
wavy-roughness.


title:
Unscreened Coulomb interactions and quantum spin Hall phase in neutral
  zigzag graphene ribbons

abstract:
  A study of the effect of unscreened Coulomb interactions on the quantum spin
Hall (QSH) phase of finite-width neutral zigzag graphene ribbons is presented.
By solving a tight-binding Hamiltonian that includes the intrinsic spin-orbit
interaction (I-SO), exact expressions for band-structures and edge-states
wavefunctions are obtained. These analytic results, supported by tight-binding
calculations, show that chiral spin-filtered edge states are composed of
localized and damped oscillatory wavefunctions, reminiscent of the ones
obtained in armchair ribbons. The addition of long-range Coulomb interactions
opens a gap in the charge sector with a gapless spin sector. In contrast to
armchair terminations, the charge-gap vanishes exponentially with the ribbon
width and its amplitude and decay-length are strongly dependent on the I-SO
coupling. Comparison with reported ab-initio calculations are presented.


title:
Ageing under oscillatory stress: Role of energy barrier distribution in
  thixotropic materials

abstract:
  In this work the ageing dynamics of soft solids of aqueous suspension of
laponite has been investigated under the oscillatory stress field. We observed
that at small stresses elastic and viscous moduli showed a steady rise with the
elastic modulus increasing at a faster rate than the viscous modulus. However
at higher stresses both the moduli underwent a sudden rise by several orders of
magnitude with the onset of rise getting shifted to a higher age for a larger
shear stress. We believe that the observed behavior is due to interaction of
barrier height distribution of the potential energy wells in which the particle
is trapped and strain induced potential energy enhancement of the particles.
Strain induced in the material causes yielding of the particles that are
trapped in the shallower wells. Those trapped in the deeper wells continue to
age enhancing the cage diffusion timescale and thereby the viscosity which
lowers the magnitude of strain allowing more particles to age. This coupled
dependence of strain, viscosity and ageing causes forward feedback for a given
magnitude of stress leading to sudden rise in both the moduli. Changing the
microstructure of the laponite suspension by adding salt affected the barrier
heights distribution that showed a profound influence on the ageing behavior.
Interestingly, this study suggests a possibility that any apparently yielded
material with negligible elastic modulus, may get jammed at a very large
waiting time.


title:
Intrinsic Spin Hall Effect in s-wave Superconducting State: Analysis of
  Rashba Model

abstract:
  A general expression for the spin Hall conductivity (SHC) in the s-wave
superconducting state at finite temperatures is derived. Based on the
expression, we study the SHC in a two-dimensional electron gas model in the
presence of Rashba spin-orbit interaction (SOI). The SHC is zero in the normal
state, whereas it takes a large negative value as soon as the superconductivity
occurs, due to the change in the quasiparticle contributions. Since this
remarkable behavior is independent of the strength of the SOI, it will be
widely observed in thin films of superconductors with surface-induced Rashba
SOI, or in various non-centrosymmetric superconductors.


title: On Measuring Split-SUSY Neutralino and Chargino Masses at the LHC

abstract:
  In Split-Supersymmetry models, where the only non-Standard Model states
produceable at LHC-energies consist of a gluino plus neutralinos and charginos,
it is conventionally accepted that only mass differences among these latter are
measureable at the LHC. The present work shows that application of a simple
`Kinematic Selection' technique allows full reconstruction of neutralino and
chargino masses from one event, in principle. A Monte Carlo simulation
demonstrates the feasibilty of using this technique at the LHC.


title: On the emergence of Lorentzian signature and scalar gravity

abstract:
  In recent years, a growing momentum has been gained by the emergent gravity
framework. Within the latter, the very concepts of geometry and gravitational
interaction are not seen as elementary aspects of Nature but rather as
collective phenomena associated to the dynamics of more fundamental objects. In
this paper we want to further explore this possibility by proposing a model of
emergent Lorentzian signature and scalar gravity. Assuming that the dynamics of
the fundamental objects can give rise in first place to a Riemannian manifold
and a set of scalar fields we show how time (in the sense of hyperbolic
equations) can emerge as a property of perturbations dynamics around some
specific class of solutions of the field equations. Moreover, we show that
these perturbations can give rise to a spin-0 gravity via a suitable
redefinition of the fields that identifies the relevant degrees of freedom. In
particular, we find that our model gives rise to Nordstrom gravity. Since this
theory is invariant under general coordinate transformations, this also shows
how diffeomorphism invariance (albeit of a weaker form than the one of general
relativity) can emerge from much simpler systems.


title: High Energy Observations of AGN Jets and their Future Prospects

abstract:
  In next five years, dramatic progress is anticipated for the AGN studies, as
we have two important missions to observe celestial sources in the high energy
regime: GLAST and Suzaku. In this talk, I will summarize recent highlights in
studies of AGN jets, focusing on the high-sensitivity X-ray observations that
may shed new light on the forthcoming GLAST era. I will especially present some
examples from most recent Suzaku observations of blazars, which provides
important hints for the shock acceleration in sub-pc scale jets, as well as
particle content in jets. Then I will focus on the neutral iron-line feature
observed in some broad line radio galaxies, as a probe of jet launching and/or
the disk-jet connection. Finally, I will discuss new results of large scale
(kpc to Mpc) jets recently resolved with Chandra X-ray observatory.
Simultaneous monitoring observations in various wavelengths will be
particularly valuable for variable blazar sources, allowing the cross
correlations of time series as well as detailed modeling of the spectral
evolution between the X-ray and gamma-ray energy bands. Possible impacts of
these new observations across the electromagnetic spectrum on various spatial
scales are discussed to challenge the long-standing mystery of AGN jet sources.


title:
A Microscopic Theory of Odd-freqeuncy Pairing in the Two-dimensional
  Extended Hubbard Model

abstract:
  We present a microscopic theory of fluctuation-mediated pairing mechanism in
a two-dimensional extended Hubbard model. In contrast to conventional wisdom,
odd-frequency spin-triplet pairing can be stabilized near the spin-density-wave
critical point. Favorable conditions for the odd-frequency pairing are the
presence of geometrical frustration and off-site Coulomb interaction.


title:
Online data processing: comparison of Bayesian regularized particle
  filters

abstract:
  The aim of this paper is to compare three regularized particle filters in an
online data processing context. We carry out the comparison in terms of hidden
states filtering and parameters estimation, considering a Bayesian paradigm and
a univariate stochastic volatility model. We discuss the use of an improper
prior distribution in the initialization of the filtering procedure and show
that the regularized Auxiliary Particle Filter (APF) outperforms the
regularized Sequential Importance Sampling (SIS) and the regularized Sampling
Importance Resampling (SIR).


title: Characterizing X-ray Variability of TeV Blazars

abstract:
  In this review, I will discuss how to characterize synchrotron X-ray
variability of TeV blazars by using the observed/simulated light curves.
Apparently, temporal studies provide independent and complementary information
to the spectral studies, but surprisingly little attention has been paid
especially for the blazar study. Only exception is a classical argument for
presence of "time lag", which may (or may not) reflect the diffrence of
synchrotron cooling timescale. Also very recently, it was suggested that the
X-ray variability of TeV blazars indicates a strong red-noise, compared to a
fractal, flickering-noise of Seyfert galaxies. Various temporal techniques are
proposed in literature, e.g., the power spectrum density (PSD), the structure
function (SF), and the discrete correlation function (DCF) and other analysis
tools, but special care must be taken if the data are not well sampled and
observation is relatively short compared to a characteristic timescale of the
system. Also, the situation is being more complicated for low-Earth orbit
satellites, e.g., ASCA, RXTE and BeppoSAX, since the light curve inevitably
contains "periodic gap" due to the Earth occultation (every ~6ksec). I will
present detailed approaches to see how the "gap" and the "finite length" of the
data affects the results of temporal analysis, and to what extent we can
believe in our results. Finally, I will briefly comment on the high-sensitivity
X-ray observations with MAXI, that may shed new light on the forthcoming GLAST
era.


title:
Ferromagnetic resonance force spectroscopy of individual sub-micron size
  samples

abstract:
  We review how a magnetic resonance force microscope (MRFM) can be applied to
perform ferromagnetic resonance (FMR) spectroscopy of \emph{individual}
sub-micron size samples. We restrict our attention to a thorough study of the
spin-wave eigen-modes excited in permalloy (Py) disks patterned out of the same
43.3 nm thin film. The disks have a diameter of either 1.0 or $0.5 \mu$m and
are quasi-saturated by a perpendicularly applied magnetic field. It is shown
that \emph{quantitative} spectroscopic information can be extracted from the
MRFM measurements. In particular, the data are extensively compared with
complementary approximate models of the dynamical susceptibility: i) a 2D
analytical model, which assumes an homogeneous magnetization dynamics along the
thickness and ii) a full 3D micromagnetic simulation, which assumes an
homogeneous magnetization dynamics below a characteristic length scale $c$ and
which approximates the cylindrical sample volume by a discretized
representation with regular cubic mesh of lateral size $c=3.9$ nm. In our
analysis, the distortions due to a breaking of the axial symmetry are taken
into account, both models incorporating the possibility of a small misalignment
between the applied field and the normal of the disks.


title:
Dynamics of Nearby Groups of Galaxies: the role of the cosmological
  constant

abstract:
  (context) Different cosmological data are consistent with an accelerated
expansion produced by an exotic matter-energy component, dubbed "dark-energy''.
A cosmological constant is a possibility since it satisfies most of the
observational constraints. (aims) In this work, the consequences of such a
component in the dynamics of groups of galaxies is investigated, aiming to
detect possible effects in scales of the order of few Mpc. (methods) The
Lema\^itre-Tolman model was modified by the inclusion of the cosmological
constant term and, from the numerical solution of the equations of motion, a
velocity-distance relation was obtained. This relation depends on two
parameters: the central core mass and the Hubble parameter. The non-linear fit
of such a relation to available data permitted to obtain masses for five nearby
groups of galaxies and for the Virgo cluster as well as estimates of the Hubble
constant. (results) The analysis of the present results indicates that the
velocity-distance relation derived from the modified Lema\^itre-Tolman model as
well as that derived from the "canonical'' model give equally acceptable fits
to the existent data. As a consequence, any robust conclusion on the effects of
the cosmological constant in the dynamics of groups could be established. The
mean value of the Hubble parameter derived from the present study of local
flows is H_0 = 65\pm 7 km/s/Mpc.


title:
Dynamic Viscosity for HFC-134a + Polyether Mixtures up to 373.15 K and
  140 MPa at Low Polyether Concentration. Measurements and Modeling

abstract:
  This paper reports viscosity data for mixtures containing a refrigerant
(HFC-134a) and a lubricant (triethylene glycol dimethyether, TriEGDME, or
tetraethylene glycol dimethyl ether, TEGDME), at 12% of TriEGDME or 14% mass
fraction of TEGDME. The measurements (140 data points) were obtained at various
pressures (between 10 and 140 MPa) in the monophasic liquid state from 293.15
to 373.15 K. Because HFC-134a and the polyethers are not in the same single
phase at normal pressure and temperature (the refrigerant is a gas, whereas the
polyethers are liquids), accurate measurements of their mixtures require
specific procedures for preparation of the samples and filling of the
apparatus. A specially designed isobaric-transfer falling-body viscometer is
used in this work. The viscosities of the mixtures are, on average, 40% higher
than that of the pure refrigerant, and this increase is more noticeable at low
temperatures. The experimental viscosities have been used to check the
predictive and correlation ability of several viscosity models (mixing rules,
Geller and Davis method, self-referencing model, hard-sphere theory,
free-volume model, and friction theory). Most of the studied models
underestimate the dynamic viscosity values over all of the temperature and
pressure ranges investigated.


title: Convex functions on Grassmannian manifolds and Lawson-Osserman problem

abstract:
  We derive estimates of the Hessian of two smooth functions defined on
Grassmannian manifold. Based on it, we can derive curvature estimates for
minimal submanifolds in Euclidean space via Gauss map. In this way, the result
for Bernstein type theorem done by Jost and the first author could be improved.


title: Late Superhumps in WZ Sge-Type Dwarf Novae

abstract:
  We report on the detection of very stable modulations with periods
unexpectedly (~0.5%) longer than superhump periods during the slowly fading
stage of WZ Sge-type superoutbursts in three systems, GW Lib, V455 And and WZ
Sge. These periods are naturally explained by assuming that these modulations
are superhumps arising from matter near the tidal truncation radius. This
finding provides an additional support to the hypothetical idea of expansion of
the accretion disk well beyond the 3:1 orbital resonance in some low mass-ratio
systems. Combined with the effect of 2:1 resonance, we present an explanation
of the origin of positive period derivatives in certain short-period SU
UMa-type dwarf novae.


title:
Magnetic Excitations of Spin-Gap System Na3Cu2SbO6 with Distorted
  Honeycomb Structure

abstract:
  Magnetic excitation spectra of quantum spins of Na3Cu2SbO6 with the distorted
honeycomb structure have been measured by neutron inelastic scattering. The
intensity distribution and the dispersion curves of the excitations indicate
that the spin system can be well understood by considering one-dimensional spin
chains formed of Cu2+ ions on a lattice of the alternation of the shorter- and
longer-spacings along the b axis. The exchange interactions between the
neighboring spins with the shorter- and longer-spacings correspond to
ferromagnetic and antiferromagnetic ones, respectively. These findings are
consistent with those we reported previously on the basis of macroscopic
measurements. The observed spin gap is 8.9 meV and the antiferromagnetic- and
ferromagnetic-interactions have been found to be 13.9 and -12.5 meV,
respectively.


title: Multiple Interactions in Herwig++

abstract:
  In this contribution we describe a new model of multiple partonic
interactions that has been implemented in Herwig++. Tuning its two free
parameters we find a good description of CDF underlying event data. We show
extrapolations to the LHC and discuss intrinsic PDF uncertainties.


title: Study of the reaction $\gamma p\to p\pi^0\eta$

abstract:
  The reaction $\gamma p\to p\pi^0\eta$ has been studied with the CBELSA
detector at the tagged photon beam of the Bonn electron stretcher facility. The
reaction shows contributions from $\Delta^+(1232)\eta$, $N(1535)^+\pi^0$ and
$pa_0(980)$ as intermediate states. A partial wave analysis suggests that the
reaction proceeds via formation of six $\Delta$ resonances,
$\Delta(1600)P_{33}$, $\Delta(1920)P_{33}$, $\Delta(1700)D_{33}$,
$\Delta(1940)D_{33}$, $\Delta(1905)F_{35}$, $\Delta(2360)D_{33}$, and two
nucleon resonances $N(1880)P_{11}$ and $N(2200)P_{13}$, for which pole
positions and decay branching ratios are given.


title: Gas flow models in the Milky Way embedded bars

abstract:
  The gas distribution and dynamics in the inner Galaxy present many unknowns
as the origin of the asymmetry of the longitude-velocity (lv) diagram of the
Central Molecular Zone (CMZ). On the other hand, there are recent evidences in
the stellar component of the presence of a nuclear bar that could be slightly
lopsided. Our goal is to characterize the nuclear bar observed in 2MASS maps
and to study the gas dynamics in the inner Milky Way taking into account this
secondary bar. We have derived a realistic mass distribution by fitting 2MASS
star counts maps with three components (disk, bulge and nuclear bar) and we
have simulated the gas dynamics, in the deduced gravitational potential, using
a sticky-particles code. Our simulations of the gas dynamics reproduce
successfully the main characteristics of the Milky Way for a bulge orientation
of 20-35 deg with respect to the Sun-Galactic Center (GC) line and a pattern
speed of 30-40 km/s/kpc. In our models the Galactic Molecular Ring (GMR) is not
an actual ring but the inner parts of the spiral arms, while the 3-kpc arm and
its far side counterpart are lateral arms that contour the bar. Our simulations
reproduce, for the first time, the parallelogram shape of the lv-diagram of the
CMZ as the gas response to the nuclear bar. This bar should be oriented by an
angle of ~60-75 deg with respect to the Sun-GC line and its mass amounts to
(2-5.5)10e9 Msun. We show that the observed asymmetry of the CMZ cannot be due
to lopsidedness of the nuclear bar as suggested by the 2MASS maps. We do not
find clear evidences of lopsidedness in the stellar potential. We propose that
the observed asymmetry of the central gas layer can be due to the infalling of
gas into the CMZ in the l=1.3-complex


title: A Universal Decline Law of Classical Novae. III. GQ Mus 1983

abstract:
  We present a unified model of infrared (IR), optical, ultraviolet (UV), and
X-ray light curves for the 1983 outburst of GQ Muscae (Nova Muscae 1983) and
estimate its white dwarf (WD) mass. Based on an optically thick wind model of
nova outbursts, we model the optical and IR light curves with free-free
emission, and the UV 1455 \AA and supersoft X-ray light curves with blackbody
emission. The best fit model that reproduces simultaneously the IR, optical, UV
1455 \AA, and supersoft X-ray observations is a 0.7 \pm 0.05 M_\sun WD for an
assumed chemical composition of the envelope, X=0.35-0.55, X_{CNO} =0.2-0.35,
and Z = 0.02, by mass weight. The mass lost by the wind is estimated to be
\Delta M_{wind} \sim 2 \times 10^{-5} M_\sun. We provide a new determination of
the reddening, E(B-V) = 0.55 \pm 0.05, and of the distance, \sim 5 kpc.
Finally, we discuss the strong UV flash that took place on JD 2,445,499 (151
days after the outburst).


title:
Observation of time correlation function of multimode two-photon pairs
  on a rubidium D$_2$ line

abstract:
  We report the generation of a type-I multimode two-photon state on a rubidium
D$_2$ line (780 nm) using periodically poled KTiOPO$_4$ crystals. With a
degenerate optical parametric oscillator far below threshold, we observe an
oscillatory correlation function, the cross-correlation between two photons
shows a cavity bandwidth of about 7.8 MHz. We also use a
Fabry-P$\acute{\rm{e}}$rot etalon to filter its most longitudinal modes and
observe its time correlation function. The experimental data are well fitted to
theoretical curves. This system could be utilized for demonstrating storage and
retrieval of narrowband photons in Rb atomic ensembles, which is important for
long-distance quantum communication.


title: Non Commutative Field Theory on Rank One Symmetric Spaces

abstract:
  Quantum field theory has been shown recently renormalizable on flat Moyal
space and better behaved than on ordinary space-time. Some models at least
should be completely finite, even beyond perturbation theory. In this paper a
first step is taken to extend such theories to non-flat backgrounds such as
solvable symmetric spaces.


title: Accretion bursts in young stars driven by cluster environment

abstract:
  The standard picture of accretion is a steady flow of matter from the disc
onto the young star - a concept which assumes the star-disc system to be
completely isolated. However, in a dense cluster environment star-disc systems
do interact gravitationally. The aim here is to estimate the encounter-induced
accretion rate in an ONC-like environment. Combining simulations of the cluster
dynamics with simulations of the effect of encounters on star-disc systems we
determine the likelihood and degree of encounter-triggered accretion processes.
We show that accretion bursts triggered by encounters of star-disc systems are
common in young dense clusters like the ONC leading in the outburst phase to
typical accretion rates of 10^(-7)-10^(-4) M(sun)/yr. Up to a third of stars
presently in the Trapezium region accreted at least 1% of their disc mass via
this mechanism in the last 1Myr. Accretion of over 6-7% of the disc material
can occur in a single encounter. Despite losing their discs quickly, the total
percentage of disc matter accreted per star is largest for the massive stars.
Supplementing the steady accretion flow there exist episodic periods of high
accretion in dense cluster environments. Due to their high accretion rate these
processes should be observable even now in some of the low-mass stars in the
ONC.


title: Non-perturbative renormalization-group approach to lattice models

abstract:
  The non-perturbative renormalization-group approach is extended to lattice
models, considering as an example a $\phi^4$ theory defined on a
$d$-dimensional hypercubic lattice. Within a simple approximation for the
effective action, we solve the flow equations and obtain the renormalized
dispersion $\eps(\q)$ over the whole Brillouin zone of the reciprocal lattice.
In the long-distance limit, where the lattice does not matter any more, we
reproduce the usual flow equations of the continuum model. We show how the
numerical solution of the flow equations can be simplified by expanding the
dispersion in a finite number of circular harmonics.


title:
Photon echoes generated by reversing magnetic field gradients in a
  rubidium vapour

abstract:
  We propose a photon echo quantum memory scheme using detuned Raman coupling
to long lived ground states. In contrast to previous 3-level schemes based on
controlled reversible inhomogeneous broadening that use sequences of
$\pi$-pulses, the scheme does not require accurate control of the coupling
dynamics to the ground states. We present a proof of principle experimental
realization of our proposal using rubidium atoms in a warm vapour cell. The
Raman resonance line is broadened using a magnetic field that varies linearly
along the direction of light propagation. Inverting the magnetic field gradient
rephases the atomic dipoles and re-emits the light pulse in the forward
direction.


title:
Classification of minimal actions of a compact Kac algebra with amenable
  dual on injective factors of type III

abstract:
  We classify a certain class of minimal actions of a compact Kac algebra with
amenable dual on injective factors of type III. Our main technical tools are
the structural analysis of type III factors and the theory of canonical
extension of endomorphisms introduced by Izumi.


title:
Quantum interference of multimode two-photon pairs with a Michelson
  interferometer

abstract:
  We experimentally observe the two-photon interference of multimode photon
pairs produced by an optical parametric oscillator far below threshold via a
michelson interferometer, which shows a multipeaked structure. We find that the
correlation function when the interferometer is unbalanced is clearly dependent
on the path difference and phase between two interfering beams, but the shape
of correlation function in balanced case is independent on the small path
difference and phase beside the height. All experimental results are well
agreed with the theoretical prediction.


title:
The magnetic field of the proto-planetary nebula candidate IRAS
  19296+2227

abstract:
  Context: Magnetic fields are thought to be one of the possible mechanisms
responsible for shaping the generally spherical outflow of evolved stars into
often aspherical planetary nebulae. However, direct measurements of magnetic
fields during the transition to the planetary nebula phase are rare.
  Aims: The aim of this project is to expand the number of magnetic field
measurements of stars in the (proto-)planetary nebula phase and find if the
magnetic field strength is sufficient to affect the stellar outflow.
  Methods: We used Very Long Baseline Array observations to measure the
circular polarization due to the Zeeman splitting of 22 GHz water masers in the
envelope of the proto-planetary nebula candidate star IRAS 19296+2227 and the
planetary nebula K3-35.
  Results: A strong magnetic field of B||=-135+-28 is detected in the water
maser region of the proto-planetary nebula candidate IRAS 19296+2227. The water
masers of K3-35 are too weak to detect circular polarization although we do
present the measurements of weak linear polarization in those masers.
  Conclusions: The field measured in the masers of IRAS 19296+2227 is
dynamically important and, if it is representative of the large scale field, is
an important factor in driving the stellar mass loss and shaping the stellar
outflow.


title: An optical view of the filament region of Abell 85

abstract:
  We compare the distribution of optically and Halpha (Ha) selected galaxies in
the Southern half of the nearby Abell 85 (A85) cluster with the recently
discovered X-ray filament (XRF). We search for galaxies where star formation
(SF) may have been triggered by interactions with intracluster gas or tidal
pressure due to the cluster potential when entering the cluster. Our analysis
is based on images obtained with CFHT MegaPrime/MegaCam (1x1 deg2 field) in
four bands (ugri) and ESO 2.2mWFI (38'x36' field) in a narrow band filter
corresponding to the redshifted Halpha (Ha) line and in a broad R-band filter.
The LFs are estimated by statistically subtracting a reference field.
Background contamination is minimized by cutting out galaxies redder than the
observed red sequence in the g-i vs. i colour-magnitude diagram. The galaxy
distribution shows a significantly flattened cluster, whose principal axis is
slightly offset from the XRF. The analysis of the broad band LFs shows that the
filament region is well populated. The filament is also independently detected
as a gravitationally bound structure by the Serna & Gerbal hierarchical method.
101 galaxies are detected in Ha, among which 23 have spectroscopic redshifts in
the cluster, 2 have spectroscopic redshifts higher than the cluster and 58 have
photometric redshifts that tend to indicate that they are background
objects.The 23 galaxies with spectroscopic redshifts in the cluster are mostly
concentrated in the South part of the cluster and along the filament. We find a
number of galaxies showing evidence for SF in the XRF, and all our results are
consistent with the previous hypothesis that the XRF in A85 is a
gravitationally bound structure made of groups falling on to the main cluster.


title:
The notion of $\psi$-weak dependence and its applications to
  bootstrapping time series

abstract:
  We give an introduction to a notion of weak dependence which is more general
than mixing and allows to treat for example processes driven by discrete
innovations as they appear with time series bootstrap. As a typical example, we
analyze autoregressive processes and their bootstrap analogues in detail and
show how weak dependence can be easily derived from a contraction property of
the process. Furthermore, we provide an overview of classes of processes
possessing the property of weak dependence and describe important probabilistic
results under such an assumption.


title:
Online network coding for optimal throughput and delay -- the
  three-receiver case

abstract:
  For a packet erasure broadcast channel with three receivers, we propose a new
coding algorithm that makes use of feedback to dynamically adapt the code. Our
algorithm is throughput optimal, and we conjecture that it also achieves an
asymptotically optimal average decoding delay at the receivers. We consider
heavy traffic asymptotics, where the load factor \rho approaches 1 from below
with either the arrival rate (\lambda) or the channel parameter (\mu) being
fixed at a number less than 1. We verify through simulations that our algorithm
achieves an asymptotically optimal decoding delay of O(1/(1-\rho)).


title: Relation Between Holonomy Groups in Superstrings, M and F-theories

abstract:
  We consider manifolds with special holonomy groups SU(3), G2 and Spin(7) as
suitable for compactification of superstrings, M-theory and F-theory (with only
one time) respectively. The relations of these groups with the octonions are
discussed, reinforcing their role in the physics of string theory and duality.
We also exhibit three triple exact sequences explaining the connections between
the mentioned special holonomy groups.


title: An Infinite Family of Generalized Kalnajs Disks

abstract:
  An infinite family of axially symmetric thin disks of finite radius is
presented. The family of disks is obtained by means of a method developed by
Hunter and contains, as its first member, the Kalnajs disk. The surface
densities of the disks present a maximum at the center of the disk and then
decrease smoothly to zero at the edge, in such a way that the mass distribution
of the higher members of the family is more concentrated at the center. The
first member of the family have a circular velocity proportional to the radius,
representing thus a uniformly rotating disk. On the other hand, the circular
velocities of the other members of the family increases from a value of zero at
the center of the disks until a maximum and then decreases smoothly until a
finite value at the edge of the disks, in such a way that for the higher
members of the family the maximum value of the circular velocity is attained
nearest the center of the disks.


title:
On the vanishing of Selmer groups for elliptic curves over ring class
  fields

abstract:
  Let E be a rational elliptic curve of conductor N without complex
multiplication and let K be an imaginary quadratic field of discriminant D
prime to N. Assume that the number of primes dividing N and inert in K is odd,
and let H be the ring class field of K of conductor c prime to ND with Galois
group G over K. Fix a complex character \chi of G. Our main result is that if
the special value of the \chi-twisted L-function of E/K is non-zero then the
tensor product (with respect to \chi) of the p-Selmer group of E/H with W over
Z[G] is 0 for all but finitely many primes p, where W is a suitable finite
extension of Z_p containing the values of \chi. Our work extends results of
Bertolini and Darmon to almost all non-ordinary primes p and also offers
alternative proofs of a \chi-twisted version of the Birch and Swinnerton-Dyer
conjecture for E over H (Bertolini and Darmon) and of the vanishing of the
p-Selmer group of E/K for almost all p (Kolyvagin) in the case of analytic rank
zero.


title: On the eve of the LHC: conceptual questions in high-energy physics

abstract:
  We start by remarks on the scientific and societal context of today's
theoretical physics. Major classes of models for physics to be explored at the
LHC are then reviewed. This leads us to propose an LHC timeline and a list of
potential effects on theoretical physics and the society. We then explore three
conceptual questions connected with the LHC physics: symmetry (and symmetry
breaking), effective field theory, and fine tuning.

categories: physics.soc-ph hep-ph hep-th physics.hist-ph


title: Early-type galaxies with core collapse supernovae

abstract:
  It is widely accepted that the progenitors of core collapse SNe are young
massive stars and therefore their host galaxies are mostly spiral or irregular
galaxies dominated by a young stellar population. Surprisingly, among
morphologically classified hosts of core collapse SNe, we find 22 cases where
the host has been classified as an Elliptical or S0 galaxy. To clarify this
apparent contradiction, we carry out a detailed morphological study and an
extensive literature search for additional information on the sample objects.
Our results are as follows: 1. Of 22 "early type" objects, 17 are in fact
misclassified spiral galaxies, one is a misclassified irregular, and one is a
misclassified ring galaxy. 2. Of the 3 objects maintaining the early type
classification, one (NGC2768) is a suspected merger remnant, another (NGC4589)
is definitely a merger, and the third (NGC2274) is in close interaction. The
presence of some amount of young stellar population in these galaxies is
therefore not unexpected. These results confirm the presence of a limited, but
significant, number of core collapse SNe in galaxies generally classified of
early type. In all cases, anyway, there are independent indicators of the
presence in host galaxies of recent star formation due to merging or
gravitational interaction.


title:
Optical Observations of GRB 050401 Afterglow : A case for Double Jet
  Model

abstract:
  The afterglow of GRB 050401 presents several novel and interesting features :
[1] An initially faster decay in optical band than in X-rays. [2] A break in
the X-ray light curve after $\sim$ 0.06 day with an unusual slope after the
break. [3] The X-ray afterglow does not show any spectral evolution across the
break while the R band light curve does not show any break.
  We have modeled the observed multi-band evolution of the afterglow of GRB
050401 as originating in a two component jet, interpreting the break in X-ray
light curve as due to lateral expansion of a narrow collimated outflow which
dominates the X-ray emission. The optical emission is attributed to a wider jet
component. Our model reproduces all the observed features of multi-band
afterglow of GRB 050401.
  We present optical observations of GRB 050401 using the 104-cm Sampurnanand
Telescope at ARIES, Nainital. Results of the analysis of multi-band data are
presented and compared with GRB 030329, the first reported case of double jet.


title: Complex Spaces and Nonstandard Schemes

abstract:
  We apply methods of nonstandard mathematics in order to regard analytic
geometry in a very different way. For example, complex spaces are seen to be
the "standard part" of certain algebraic nonstandard schemes. We construct a
category of such schemes, sitting in between usual algebraic schemes (over the
complex numbers) and that of complex spaces. We clarify the structure of prime
ideals in a Stein algebra, coming from nonstandard points and show in
particular that ANY maximal and minimal prime ideal in a Stein algebra is the
vanishing ideal of a nonstandard point. Other applications of our point of view
are given for differential forms (a la Leibniz), generic points (as nonstandard
ones), meromorphic functions, hyperbolicity. The essential tools taken from
nonstandard mathematics and adapted for our purposes, are summarized in the
appendix.


title: Chaotic and regular motion around generalized Kalnajs discs

abstract:
  The motion of test particles in the gravitational fields generated by the
first four members of the infinite family of generalized Kalnajs discs, is
studied. In first instance, we analyze the stability of circular orbits under
radial and vertical perturbations and describe the behavior of general
equatorial orbits and so we find that radial stability and vertical instability
dominate such disc models. Then we study bounded axially symmetric orbits by
using the Poincare surfaces of section and Lyapunov characteristic numbers and
find chaos in the case of disc-crossing orbits and completely regular motion in
other cases.


title: Heavy sterile neutrinos and supernova explosions

abstract:
  We consider sterile neutrinos with rest masses ~0.2 GeV. Such sterile
neutrinos could augment core collapse supernova shock energies by enhancing
energy transport from the core to the vicinity of the shock front. The decay of
these neutrinos could produce a flux of very energetic active neutrinos,
detectable by future neutrino observations from a galactic supernova. The
relevant range of sterile neutrino masses and mixing angles can be probed in
future laboratory experiments.


title:
A Multiferroic Ceramic with Perovskite Structure:
  La0.5Bi0.5Mn0.5Fe0.5O3.09

abstract:
  ABO3 perovskite multiferroic La0.5Bi0.5Mn0.5Fe0.5O3.09 where the B-site
cations is responsible for the magnetic properties and the A-site cation with
lone pair electron is responsible for the ferroelectric properties was
synthesized at normal conditions. This oxide exhibits a ferromagnetic
transition around 240 K with a well defined hysteresis loop, and a significant
reversible remnant polarization below 67K similar to ferroelectric behavior.
The magnetic interaction is interpreted by the ferromagnetic Fe3+-O-Mn3+ and
antiferromagnetic Fe3+(Mn3+)-O-Fe3+(Mn3+) interactions competed each other,
whereas the ferroelectricity is predominantly due to the polar nature
introduced by the 6s2 lone pair of Bi3+ cations


title: Distribution functions for a family of axially symmetric galaxy models

abstract:
  We present the derivation of distribution functions for the first four
members of a family of disks, previously obtained in (MNRAS, 371, 1873, 2006),
which represent a family of axially symmetric galaxy models with finite radius
and well behaved surface mass density. In order to do this we employ several
approaches that have been developed starting from the potential-density pair
and, essentially using the method introduced by Kalnajs (Ap. J., 205, 751,
1976) we obtain some distribution functions that depend on the Jacobi integral.
Now, as this method demands that the mass density can be properly expressed as
a function of the gravitational potential, we can do this only for the first
four discs of the family. We also find another kind of distribution functions
by starting with the even part of the previous distribution functions and using
the maximum entropy principle in order to find the odd part and so a new
distribution function, as it was pointed out by Dejonghe (Phys. Rep., 133, 217,
1986). The result is a wide variety of equilibrium states corresponding to
several self-consistent finite flat galaxy models.


title:
Communities recognition in the Chesapeake Bay ecosystem by dynamical
  clustering algorithms based on different oscillators systems

abstract:
  We have recently introduced an efficient method for the detection and
identification of modules in complex networks, based on the de-synchronization
properties (dynamical clustering) of phase oscillators. In this paper we apply
the dynamical clustering tecnique to the identification of communities of
marine organisms living in the Chesapeake Bay food web. We show that our
algorithm is able to perform a very reliable classification of the real
communities existing in this ecosystem by using different kinds of dynamical
oscillators. We compare also our results with those of other methods for the
detection of community structures in complex networks.

categories: q-bio.PE cond-mat.stat-mech physics.bio-ph physics.soc-ph


title:
An Infinite Family of Self-consistent Models for Axisymmetric Flat
  Galaxies

abstract:
  We present the formulation of a new infinite family of self-consistent
stellar models, designed to describe axisymmetric flat galaxies. The
corresponding density-potential pair is obtained as a superposition of members
belonging to the generalized Kalnajs family, by imposing the condition that the
density can be expressed as a regular function of the gravitational potential,
in order to derive analytically the corresponding equilibrium distribution
functions (DF). The resulting models are characterized by a well-behaved
surface density, as in the case of generalized Kalnajs discs. Then, we present
a study of the kinematical behavior which reveals, in some particular cases, a
very satisfactory behavior of the rotational curves (without the assumption of
a dark matter halo). We also analyze the equatorial orbit's stability and
Poincare surfaces of section are performed for the 3-dimensional orbits.
Finally, we obtain the corresponding equilibrium DFs, using the approaches
introduced by Kalnajs (Ap. J., 205, 751, 1976) and Dejonghe (Phys. Rep., 133
(3-4), 217, 1986).


title:
Dynamic programming for infinite horizon boundary control problems of
  PDE's with age structure

abstract:
  We develop the dynamic programming approach for a family of infinite horizon
boundary control problems with linear state equation and convex cost. We prove
that the value function of the problem is the unique regular solution of the
associated stationary Hamilton--Jacobi--Bellman equation and use this to prove
existence and uniqueness of feedback controls. The idea of studying this kind
of problem comes from economic applications, in particular from models of
optimal investment with vintage capital. Such family of problems has already
been studied in the finite horizon case by Faggian. The infinite horizon case
is more difficult to treat and it is more interesting from the point of view of
economic applications, where what mainly matters is the behavior of optimal
trajectories and controls in the long run. The study of infinite horizon is
here performed through a nontrivial limiting procedure from the corresponding
finite horizon problem.


title:
Different resistivity response to spin density wave and
  superconductivity at 20 K in $Ca_{1-x}Na_xFe_2As_2$

abstract:
  We report that intrinsic transport and magnetic properties, and their
anisotropy from high quality single crystal $CaFe_2As_2$. The resistivity
anisotropy ($\rho_c/\rho_{ab}$) is $\sim 50 $, and less than 150 of
$BaFe_2As_2$, which arises from the strong coupling along c-axis due to an
apparent contraction of about 0.13 nm compared to $BaFe_2As_2$. Temperature
independent anisotropy indicates that the transport in ab plane and along
c-axis direction shares the same scattering mechanism. In sharp contrast to the
case of parent compounds $ROFeAs$ (R=rare earth) and $MFe_2As_2$ (M=Ba and Sr),
spin-density-wave (SDW) ordering (or structural transition) leads to a steep
increase of resistivity in $CaFe_2As_2$. Such different resistivity response to
SDW ordering is helpful to understand the role played by SDW ordering in
Fe-based high-$T_c$ superconductors. The susceptibility behavior is very
similar to that observed in single crystal $BaFe_2As_2$. A linear temperature
dependent susceptibility occurs above SDW transition of about 165 K. Partial
substitution of Na for Ca suppresses the SWD ordering (anomaly in resistivity)
and induces occurrence of superconductivity at $\sim 20$ K.


title: Large-scale structure of a nation-wide production network

abstract:
  Production in an economy is a set of firms' activities as suppliers and
customers; a firm buys goods from other firms, puts value added and sells
products to others in a giant network of production. Empirical study is lacking
despite the fact that the structure of the production network is important to
understand and make models for many aspects of dynamics in economy. We study a
nation-wide production network comprising a million firms and millions of
supplier-customer links by using recent statistical methods developed in
physics. We show in the empirical analysis scale-free degree distribution,
disassortativity, correlation of degree to firm-size, and community structure
having sectoral and regional modules. Since suppliers usually provide credit to
their customers, who supply it to theirs in turn, each link is actually a
creditor-debtor relationship. We also study chains of failures or bankruptcies
that take place along those links in the network, and corresponding
avalanche-size distribution.


title:
Fokker-Planck-Rosenbluth-Type Equations for Self-gravitating Systems in
  1PN Approximation

abstract:
  We present two formulations of Fokker-Planck-Rosenbluth-type (FPR) equations
for many-particle self-gravitating systems, with first order relativistic
corrections in the post-Newtonian approach (1PN). The first starts from a
covariant Fokker-Planck equation for a simple gas, introduced recently by G.
Chacon-Acosta and G. Kremer (Phys. Rev. E 76, 021201, 2007). The second
derivation is based on the establishment of an 1PN-BBGKY hierarchy, developed
systematically from the 1PN microscopic law of force and using the
Klimontovich-Dupree (KD) method. We close the hierarchy by the introduction of
a two-point correlation function that describes adequately the relaxation
process. This picture reveals an aspect that is not considered in the first
formulation: the contribution of ternary correlation patterns to the diffusion
coefficients, as a consequence of the nature of 1PN interaction. Both
formulations can be considered as a generalization of the equation derived by
Rezania and Sobouti (Astron. Astrophys. 54, 1110-1114, 2000), to stellar
systems where the relativistic effects of gravitation play a significant role.


title:
Chaotic Motion Around Stellar Objects with Octupolar Deformation:
  Newtonian and Post Newtonian Approaches

abstract:
  Regular and chaotic test particle motion in gravitational fields due to
stellar bodies with quadrupolar and octupolar deformation are studied using
Poincare surfaces of section. In first instance, we analyze the purely
Newtonian case and we find that the octupolar term induces a distortion in the
KAM curves corresponding to regular trajectories as well as an increase in
chaoticity, even in the case corresponding to oblate deformation. Then we
examine the effect of the first general relativistic corrections, provided by
the post Newtonian approach. For typical values of the post Newtonian
multipoles we find that the phase-space structure practically remains the same
as in the classical case, whereas that for certain larger values of these
multipoles the chaoticity vanishes. This important fact provides an interesting
example of a situation where a non-integrable dynamical system becomes
integrable through the introduction of a large perturbation.


title: Synchronization and Dephasing of Many-Body States in Optical Lattices

abstract:
  We introduce an approach to describe quantum-coherent evolution of a system
of cold atoms in an optical lattice triggered by a change in superlattice
potential. Using a time-dependent mean field description, we map the problem to
a strong coupling limit of previously studied time-dependent BCS model. We
compare the mean field dynamics to a simulation using light-cone methods and
find reasonable agreement for numerically accessible times. The mean field
model is integrable, and gives rise to a rich behavior, in particular to beats
and recurrences in the order parameter, as well as singularities in the
momentum distribution, directly measureable in cold atom experiment.


title: Entropy of meromorphic maps and dynamics of birational maps

abstract:
  We study the dynamics of meromorphic maps for a compact Kaehler manifold X.
More precisely, we give a simple criterion that allows us to produce a measure
of maximal entropy. We can apply this result to bound the Lyapunov exponents.
  Then, we study the particular case of a family of generic birational maps of
P^k for which we construct the Green currents and the equilibrium measure. We
use for that the theory of super-potentials. We show that the measure is mixing
and gives no mass to pluripolar sets. Using the criterion we get that the
measure is of maximal entropy. It implies finally that the measure is
hyperbolic.


title: Finite axisymmetric charged dust disks in conformastatic spacetimes

abstract:
  An infinite family of axisymmetric charged dust disks of finite extension is
presented. The disks are obtained by solving the vacuum Einstein-Maxwell
equations for conformastatic spacetimes, which are characterized by only one
metric function. In order to obtain the solutions, it is assumed that the
metric function and the electric potential are functionally related and that
the metric function is functionally dependent of another auxiliary function,
which is taken as a solution of Laplace equation. The solutions for the
auxiliary function are then taken as given by the infinite family of
generalized Kalnajs disks recently obtained by Gonz\'alez and Reina (MNRAS 371,
1873, 2006), which is expressed in terms of the oblate spheroidal coordinates
and represents a well behaved family of finite axisymmetric flat galaxy models.
The so obtained relativistic thin disks have then a charge density that is
equal, except maybe by a sign, to their mass density, in such a way that the
electric and gravitational forces are in exact balance. The energy density of
the disks is everywhere positive and well behaved, vanishing at the edge.
Accordingly, as the disks are made of dust, their energy-momentum tensor it
agrees with all the energy conditions.


title:
Implementation for blow up of tornado-type solutions for complex version
  of 3D Navier-Stokes system

abstract:
  We consider Cauchy problem for Fourier transformation of 3-dimensional
Navier-Stokes system with zero external force. Using initial data purposed by
Dong Li and Ya.G.Sinai we implement self-similar regime producing fast growing
behavior of the energy of solution while time tends to critical value.


title:
Subwavelength microscope that uses frequency scanning for image
  reconstruction

abstract:
  A new principle of subwavelength imaging based on frequency scanning is
considered. It is shown that it is possible to reconstruct the spatial profile
of an external field exciting an array (or coupled arrays) of
subwavelength-sized resonant particles with a frequency scan over the whole
band of resonating array modes. During the scan it is enough to measure and
store the values of the near field at one or at most two points. After the scan
the distribution of the near field can be reconstructed with simple
post-processing. The proposed near-field microscope has no moving parts.


title: Pedestrian Dynamics With Event-driven Simulation

abstract:
  The social-force model is systematically modified to achieve a satisfying
agreement with the fundamental diagram. Furthermore, our modification allows an
efficient computation of the simulation. Finally, different simulation-results
will be compared to empirical data.


title:
Deterministic Dense Coding and Faithful Teleportation with Multipartite
  Graph States

abstract:
  We proposed novel schemes to perform the deterministic dense coding and
faithful teleportation with multipartite graph states. We also find the
sufficient and necessary condition of a viable graph state for the proposed
scheme. That is, for the associated graph, the reduced adjacency matrix of the
Tanner-type subgraph between senders and receivers should be invertible.


title: Delta resonances, quark models, chiral symmetry and AdS/QCD

abstract:
  The mass spectrum of Delta resonances is compared to predictions based on
three quark-model variants, to predictions assuming that chiral symmetry is
restored in high-mass baryon resonances, and to predictions derived from
AdS/QCD. The latter approach yields a nearly perfect agreement when the
confinement property of QCD is modeled by a soft wall in AdS.


title: Chaos Pass Filter: Linear Response of Synchronized Chaotic Systems

abstract:
  The linear response of synchronized chaotic units with delayed couplings and
feedback to small external perturbations is investigated in the context of
communication with chaos synchronization. For iterated chaotic maps, the
distribution of distances is calculated numerically and, for some special
cases, analytically as well. Depending on model parameters, this distribution
has power law tails leading to diverging moments of distances in the region of
synchronization. The corresponding linear equations have multiplicative and
additive noise due to perturbations and chaos. The response to small harmonic
perturbations shows resonances related to coupling and feedback delay times.
For perturbation from a binary message the bit error rate is calculated. The
bit error rate is not related to the transverse Lyapunov exponents, and it can
be reduced when additional noise is added to the transmitted signal. For some
special cases, the bit error rate as a function of coupling strength has the
structure of a devil's staircase, related to an iterated function system.
Finally, the security of communication is discussed by comparing uni- and
bi-directional couplings.


title:
Mass Deformations of Super Yang-Mills Theories in D= 2+1, and
  Super-Membranes: A Note

abstract:
  Mass deformations of supersymmetric Yang-Mills theories in three spacetime
dimensions are considered. The gluons of the theories are made massive by the
inclusion of a non-local gauge and Poincare invariant mass term due to
Alexanian and Nair, while the matter fields are given standard Gaussian
mass-terms. It is shown that the dimensional reduction of such mass deformed
gauge theories defined on $R^3$ or $R\times T^2$ produces matrix quantum
mechanics with massive spectra. In particular, all known massive matrix quantum
mechanical models obtained by the deformations of dimensional reductions of
minimal super Yang-Mills theories in diverse dimensions are shown also to arise
from the dimensional reductions of appropriate massive Yang-Mills theories in
three spacetime dimensions. Explicit formulae for the gauge theory actions are
provided.


title: Scalar Quantization for Audio Data Coding

abstract:
  This paper is concerned with scalar quantization of transform coefficients in
an audio codec. The generalized Gaussian distribution (GGD) is used as an
approximation of one-dimensional probability density function for transform
coefficients obtained by modulated lapped transform (MLT) or modified cosine
transform (MDCT) filterbank. The rationale of the model is provided in
comparison with theoretically achievable rate-distortion function. The
rate-distortion function computed for the random sequence obtained from a real
sequence of samples from a large database is compared with that computed for
random sequence obtained by a GGD random generator. A simple algorithm of
constructing the Extended Zero Zone (EZZ) quantizer is proposed. Simulation
results show that the EZZ quantizer yields a negligible loss in terms of coding
efficiency compared to optimal scalar quantizers. Furthermore, we describe an
adaptive version of the EZZ quantizer which works efficiently with low bitrate
requirements for transmitting side information


title:
Beyond Parametrics in Interdisciplinary Research: Festschrift in Honor
  of Professor Pranab K. Sen

abstract:
  Pranab K. Sen has contributed extensively to many areas of Statistics
including order statistics, nonparametrics, robust inference, sequential
methods, asymptotics, biostatistics, clinical trials, bioenvironmental studies
and bioinformatics. His long list of over 600 publications and 22 books and
volumes along with numerous citations during the past 5 decades bear testimony
to his work. All three of us have had the good fortune of being associated with
him in different capacities. He has given professional and personal advice on
many occasions to all of us, and we feel that our lives have certainly been
enriched by our association with him. He has been over the years a friend,
philosopher and a guide to us, and still continues to be one! While parametric
statistical inference remains ever so popular, semi-parametric, Bayesian and
nonparametric inferential methods have attracted great attention from numerous
applied scientists because of their weaker assumptions, which make them
naturally robust and so more appropriate in real-life applications. This
clearly signals for ``beyond parametrics'' approaches which include
nonparametrics, semi-parametrics, Bayes methods and many others. Motivated by
this feature, and his drive in the ``beyond parametrics'' area, we thought that
it will be only appropriate for a volume in honor of Pranab Kumar Sen to focus
on this aspect of statistical inference and its applications. With this in
mind, we have put together this volume in order to (i) review some of the
recent developments in this direction, (ii) focus on some new methodologies and
highlight their applications, and (iii) suggest some interesting open problems
and possible new directions for further research.


title:
The complete menu of eligible metrics for a family of toy Hamiltonians
  $H \neq H^\dagger$ with real spectra

abstract:
  An elementary set of non-Hermitian $N$ by $N$ matrices $H^{(N)}(\lambda) \neq
[ H^{(N)}(\lambda)]^\dagger$ with real spectra is considered, assuming that
each of these matrices represents a selfadjoint quantum Hamiltonian in an {\it
ad hoc} Hilbert space of states ${\cal H}^{(physical)}$. The problem of an
explicit specification of all of these spaces (i.e., in essence, of all of the
eligible {\it ad hoc} inner products and metric operators $\Theta$) is
addressed. The problem is shown exactly solvable and, for every size
$N=2,4,...$ and parameter $\lambda \in (-1,1)$ in matrix $H^{(N)}(\lambda)$,
the complete $N-$parametric set of metrics
$\Theta^{(N)}_{\alpha_1,\alpha_2,...,\alpha_N}(\lambda)$ is recurrently defined
by closed formula.


title:
Gamow-Hartree-Fock-Bogoliubov Method: Representation of quasiparticles
  with Berggren sets of wave functions

abstract:
  Single-particle resonant states, also called Gamow states, as well as bound
and scattering states of complex energy form a complete set, the Berggren
completeness relation. It is the building block of the recently introduced
Gamow Shell Model, where weakly bound and resonant nuclear wave functions are
expanded with a many-body basis of Slater Determinants generated by this set of
single-particle states. However, Gamow states have never been studied in the
context of Hartree-Fock-Bogoliubov theory, except in the
Bardeen-Cooper-Schriefer (BCS) approximation, where both the upper and lower
components of a quasiparticle wave function are assumed to possess the same
radial dependence with that of a Gamow state associated with the Hartree-Fock
potential. Hence, an extension of the notion of Gamow state has to be effected
in the domain of quasiparticles. It is shown theoretically and numerically that
bound, resonant and scattering quasiparticles are well defined and form a
complete set, by which bound Hartree-Fock-Bogoliubov ground states can be
constructed. It is also shown that the Gamow-Hartree-Fock single-particle basis
can be used to solve the Gamow-Hartree-Fock-Bogoliubov problem. As an
illustration, the proposed method is applied to neutron-rich Nickel isotopes
close to the neutron drip-line.


title: The Effective Theory of the Light Stop Scenario

abstract:
  Electroweak baryogenesis in the minimal supersymmetric extension of the
Standard Model may be realized within the light stop scenario, where the
right-handed stop mass remains close to the top-quark mass to allow for a
sufficiently strong first order electroweak phase transition. All other
supersymmetric scalars are much heavier to comply with the present bounds on
the Higgs mass and the electron and neutron electric dipole moments. Heavy
third generation scalars render it necessary to resum large logarithm
contributions to perform a trustable Higgs mass calculation. We have studied
the one--loop RGE improved effective theory below the heavy scalar mass scale
and obtained reliable values of the Higgs mass. Moreover, assuming a common
mass $\tilde m$ for all heavy scalar particles, and values of all gaugino
masses and the Higgsino mass parameter about the weak scale, and imposing gauge
coupling unification, a two-loop calculation yields values of the mass $\tilde
m$ in the interval between three TeV and six hundred TeV. Furthermore for a
stop mass around the top quark mass, this translates into an upper bound on the
Higgs mass of about 150 GeV. The Higgs mass bound becomes even stronger, of
about 129 GeV, for the range of stop and gaugino masses consistent with
electroweak baryogenesis. The collider phenomenology implications of this
scenario are discussed in some detail.


title:
Relativistic BCS Theory in Quasi-(2+1)-Dimensions: Effects of an
  Inter-layer Transfer in the Honeycomb Lattice Symmetry

abstract:
  Motivated by recent huge interests on graphene sheet and graphite as
"relativistic" systems, a BCS superconductivity in a quasi-(2+1)-dimensional
relativistic model is investigated. The intra-layer particle dynamics is
described by a (2+1)-dimensional Gross-Neveu-type four-body contact interaction
model, while inter-layer particle motions will be caused by a hopping term with
a transfer parameter $t$. Especially, we examine the effects of non-vanishing
$t$, chemical potential $\mu$, and a mass parameter $m$ which will give a gap
at a conical intersection point of the relativistic band dispersion, in the BCS
s-wave (scalar) superconducting gap function $\Delta$.

categories: cond-mat.supr-con cond-mat.mes-hall cond-mat.str-el hep-ph


title: Quaternion typification of Clifford algebra elements

abstract:
  We present a new classification of Clifford algebra elements. Our
classification is based on the notion of quaternion type. Using this
classification we develop a method for analyzing of commutators and
anticommutators of Clifford algebra elements. This method allows us to find out
and prove a number of new properties of Clifford algebra elements.


title: Proof of Ira Gessel's Lattice Path Conjecture

abstract:
  We present a computer-aided, yet fully rigorous, proof of Ira Gessel's
tantalizingly simply-stated conjecture that the number of ways of walking $2n$
steps in the region $x+y \geq 0, y \geq 0$ of the square-lattice with unit
steps in the east, west, north, and south directions, that start and end at the
origin, equals $16^n\frac{(5/6)_n(1/2)_n}{(5/3)_n(2)_n}$ .


title:
The Statistics of the Work Done on a Quantum Critical System by
  Quenching a Control Parameter

abstract:
  We study the statistics of the work done on a quantum critical system by
quenching a control parameter in the Hamiltonian. We elucidate the relation
between the probability distribution of the work and the Loschmidt echo, a
quantity emerging usually in the context of dephasing. Using this connection we
characterize the statistics of the work done on a quantum Ising chain by
quenching locally or globally the transverse field. We show that for local
quenches starting at criticality the probability distribution of the work
displays an interesting edge singularity.


title:
Observation of the suppression of the flux of cosmic rays above
  4x10^19eV

abstract:
  The energy spectrum of cosmic rays above 2.5x10^18eV, derived from 20,000
events recorded at the Pierre Auger Observatory, is described. The spectral
index gamma of the flux, J ~ E^-gamma, at energies between 4x10^18eV and
4x10^19eV is 2.69+-0.02(stat)+-0.06(syst), steepening to
4.2+-0.4(stat)+-0.06(syst) at higher energies, consistent with the prediction
by Greisen and by Zatsepin and Kuz'min.


title: Nonequilibrium Invariant Measure under Heat Flow

abstract:
  We provide an explicit representation of the nonequilibrium invariant measure
for a chain of harmonic oscillators with conservative noise in the presence of
stationary heat flow. By first determining the covariance matrix, we are able
to express the measure as the product of Gaussian distributions aligned along
some collective modes that are spatially localized with power-law tails.
Numerical studies show that such a representation applies also to a purely
deterministic model, the quartic Fermi-Pasta-Ulam chain.


title: Bound on four-dimensional Planck mass

abstract:
  In this note we derive a bound using data from cosmic rays physics on a model
recently proposed to solve the hierarchy problem by lowering the Planck scale
to the TeV region without the introduction of extra-dimensions. We show that
the non observation of small black holes by AGASA implies a model independent
limit for the four-dimensional reduced Planck mass of roughly 488 GeV.


title:
Exchange of high and low energy photons in ultraperipheral relativistic
  heavy-ion collisions

abstract:
  Ultraperipheral collisions at collider energies are a useful tool to study
photon-hadron (proton/nucleus) and photon-photon interactions in a hitherto
unexplored energy regime. Theoretical tools to study these processes are
briefly described. Some current results and problems are discussed


title: TRIS III: the diffuse galactic radio emission at $\delta=+42^{\circ}$

abstract:
  We present values of temperature and spectral index of the galactic diffuse
radiation measured at 600 and 820 MHz along a 24 hours right ascension circle
at declination $\delta = +42^{\circ}$. They have been obtained from a subset of
absolute measurements of the sky temperature made with TRIS, an experiment
devoted to the measurement of the Cosmic Microwave Background temperature at
decimetric-wavelengths with an angular resolution of about $20^{\circ}$.
  Our analysis confirms the preexisting picture of the galactic diffuse
emission at decimetric wavelength and improves the accuracy of the measurable
quantities. In particular, the signal coming from the halo has a spectral index
in the range $2.9-3.1$ above 600 MHz, depending on the sky position. In the
disk, at TRIS angular resolution, the free-free emission accounts for the 11%
of the overall signal at 600 MHz and 21% at 1420 MHz. The polarized component
of the galactic emission, evaluated from the survey by Brouw and Spoelstra,
affects the observations at TRIS angular resolution by less than 3% at 820 MHz
and less than 2% at 600 MHz. Within the uncertainties, our determination of the
galactic spectral index is practically unaffected by the correction for
polarization.
  Since the overall error budget of the sky temperatures measured by TRIS at
600 MHz, that is 66 mK(systematic)$+$18 mK (statistical), is definitely smaller
than those reported in previous measurements at the same frequency, our data
have been used to discuss the zero levels of the sky maps at 150, 408, 820 and
1420 MHz in literature. Concerning the 408 MHz survey, limiting our attention
to the patch of sky corresponding to the region observed by TRIS, we suggest a
correction of the base-level of $(+3.9\pm 0.6)$K.


title: Blowing up Feynman integrals

abstract:
  In this talk we discuss sector decomposition. This is a method to disentangle
overlapping singularities through a sequence of blow-ups. We report on an
open-source implementation of this algorithm to compute numerically the Laurent
expansion of divergent multi-loop integrals. We also show how this method can
be used to prove a theorem which relates the coefficients of the Laurent series
of dimensionally regulated multi-loop integrals to periods.


title:
Deformation of central charges, vertex operator algebras whose Griess
  algebras are Jordan algebras

abstract:
  If a vertex operator algebra $V=\oplus_{n=0}^{\infty}V_n$ satisfies $\dim
V_0=1, V_1=0$, then $V_2$ has a commutative (nonassociative) algebra structure
called Griess algebra. One of the typical examples of commutative
(nonassociative) algebras is a Jordan algebra. For example, the set $Sym_d(\C)$
of symmetric matrices of degree $d$ becomes a Jordan algebra. On the other
hand, in the theory of vertex operator algebras, central charges influence the
properties of vertex operator algebras. In this paper, we construct vertex
operator algebras with central charge $c$ and its Griess algebra is isomorphic
to $Sym_d(\C)$ for any complex number $c$.


title: Wilsonian renormalization, differential equations and Hopf algebras

abstract:
  In this paper, we present an algebraic formalism inspired by Butcher's
B-series in numerical analysis and the Connes-Kreimer approach to perturbative
renormalization. We first define power series of non linear operators and
propose several applications, among which the perturbative solution of a fixed
point equation using the non linear geometric series. Then, following
Polchinski, we show how perturbative renormalization works for a non linear
perturbation of a linear differential equation that governs the flow of
effective actions. Then, we define a general Hopf algebra of Feynman diagrams
adapted to iterations of background field effective action computations. As a
simple combinatorial illustration, we show how these techniques can be used to
recover the universality of the Tutte polynomial and its relation to the
$q$-state Potts model. As a more sophisticated example, we use ordered diagrams
with decorations and external structures to solve the Polchinski's exact
renormalization group equation. Finally, we work out an analogous construction
for the Schwinger-Dyson equations, which yields a bijection between planar
$\phi^{3}$ diagrams and a certain class of decorated rooted trees.


title:
Strong dissipation inhibits losses and induces correlations in cold
  molecular gases

abstract:
  Atomic quantum gases in the strong-correlation regime offer unique
possibilities to explore a variety of many-body quantum phenomena. Reaching
this regime has usually required both strong elastic and weak inelastic
interactions, as the latter produce losses. We show that strong inelastic
collisions can actually inhibit particle losses and drive a system into a
strongly-correlated regime. Studying the dynamics of ultracold molecules in an
optical lattice confined to one dimension, we show that the particle loss rate
is reduced by a factor of 10. Adding a lattice along the one dimension
increases the reduction to a factor of 2000. Our results open up the
possibility to observe exotic quantum many-body phenomena with systems that
suffer from strong inelastic collisions.


title: Macroscopic Coulomb blockade in large Josephson junction arrays

abstract:
  We investigate theoretically transport properties of one- and two-dimensional
regular Josephson junction arrays (JJAs) in an insulating state. We derive the
low-temperature current-voltage characteristics for the current mediated by the
Cooper pair transfer across the system. In the case where the screening length
associated with the capacitance of the islands to the ground is much larger
than the island's size, we find that transport is governed by the macroscopic
Coulomb blockade effect with the gap well exceeding a single island charging
energy. In the limit when the screening length is much larger than the linear
size of the array, the gap establishes the dependence on the array size,
namely, the Coulomb gap grows linearly with the system size in 1D and grows as
logarithm of the system size in the two-dimensional array. We find two
transport regimes: At moderate temperatures, above the BKT-like charge
binding-unbinding transition the low bias transport is thermally activated, the
activation energy being equal to the Coulomb blockade energy. At low
temperatures, below the binding-unbinding transition, a JJA falls into a
superinsulating state with the resistance exhibiting a double-exponential
temperature dependence.


title:
The ISM in spiral galaxies: can cooling in spiral shocks produce
  molecular clouds?

abstract:
  We investigate the thermodynamics of the ISM and the formation of molecular
hydrogen through numerical simulations of spiral galaxies. The model follows
the chemical, thermal and dynamical response of the disc to an external spiral
potential. Self-gravity and magnetic fields are not included. The calculations
demonstrate that gas can cool rapidly when subject to a spiral shock. Molecular
clouds in the spiral arms arise through a combination of compression of the ISM
by the spiral shock and orbit crowding. These results highlight that local
self-gravity is not required to form molecular clouds. Self-shielding provides
a sharp transition density, below which gas is essentially atomic, and above
which the molecular gas fraction is >0.001. The timescale for gas to move
between these regimes is very rapid (<~1 Myr). From this stage, the majority of
gas generally takes between 10 to 20 Myr to obtain high H$_{2}$ fractions (>50
%). Although our calculations are unable to resolve turbulent motions on scales
smaller than the spiral arm and do not include self-gravity. True cloud
formation timescales are therefore expected to be even shorter.
  The mass budget of the disc is dominated by cold gas residing in the spiral
arms. Between 50 and 75 % of this gas is in the atomic phase. When this gas
leaves the spiral arm and drops below the self-shielding limit it is heated by
the galactic radiation field. Consequently, most of the volume in the interarm
regions is filled with warm atomic gas. However, some cold spurs and clumps can
survive in interarm regions for periods comparable to the interarm passage
timescale. Altogether between 7 and 40% of the gas in our disc is molecular,
depending on the surface density of the calculation, with approximately 20%
molecular for a surface density comparable to the solar neighbourhood.


title: The doubly periodic Scherk-Costa surfaces

abstract:
  We present a new family of embedded doubly periodic minimal surfaces, of
which the symmetry group does not coincide with any other example known before.


title: What to Expect from Transiting Multiplanet Systems

abstract:
  So far radial velocity (RV) measurements have discovered ~25 stars to host
multiple planets. The statistics imply that many of the known hosts of
transiting planets should have additional planets, yet none have been solidly
detected. They will be soon, via complementary search methods of RV,
transit-time variations (TTV) of the known planet, and transits of the
additional planet. When they are found, what can transit measurements add to
studies of multiplanet dynamical evolution? First, mutual inclinations become
measurable, for comparison to the solar system's disk-like configuration. Such
measurements will give important constraints to planet-planet scattering
models, just as the RV measurements of eccentricity have done. Second, the
Rossiter-McLaughlin effect measures stellar obliquity, which can be modified by
two-planet dynamics with a tidally evolving inner planet. Third, TTV is
exquisitely sensitive to planets in mean motion resonance. Two planets
differentially migrating in the disk can establish such resonances, and tidal
evolution of the planets can break them, so the configuration and frequency of
these resonances as a function of planetary parameters will constrain these
processes.


title: On timelike surfaces in Lorentzian manifolds

abstract:
  We discuss the geometry of timelike surfaces (two-dimensional submanifolds)
in a Lorentzian manifold and its interpretation in terms of general relativity.
A classification of such surfaces is presented which distinguishes four cases
of special algebraic properties of the second fundamental form from the generic
case. In the physical interpretation a timelike surface can be viewed as the
worldsheet of a ``track'', and timelike curves in this surface can be viewed as
the worldlines of observers who are bound to the track, like someone sitting in
a roller-coaster car. With this interpretation, our classification turns out to
be closely related to (i) the visual appearance of the track, (ii) gyroscopic
transport along the track, and (iii) inertial forces perpendicular to the
track. We illustrate our general results with timelike surfaces in the
Kerr-Newman spacetime.


title:
Density probability distribution functions of diffuse gas in the Milky
  Way

abstract:
  In a search for the signature of turbulence in the diffuse interstellar
medium in gas density distributions, we determined the probability distribution
functions (PDFs) of the average volume densities of the diffuse gas. The
densities were derived from dispersion measures and HI column densities towards
pulsars and stars at known distances. The PDFs of the average densities of the
diffuse ionized gas (DIG) and the diffuse atomic gas are close to lognormal,
especially when lines of sight at |b|<5 degrees and |b|>=5 degrees are
considered separately. The PDF of <n_HI> at high |b| is twice as wide as that
at low |b|. The width of the PDF of the DIG is about 30 per cent smaller than
that of the warm HI at the same latitudes. The results reported here provide
strong support for the existence of a lognormal density PDF in the diffuse ISM,
consistent with a turbulent origin of density structure in the diffuse gas.


title: Varying Alpha: New Constraints from Seasonal Variations

abstract:
  We analyse the constraints obtained from new atomic clock data on the
possible time variation of the fine structure `constant' and the
electron-proton mass ratio and show how they are strengthened when the seasonal
variation of Sun's gravitational field at the Earth's surface is taken into
account. We compare these bounds with those obtainable from tests of the Weak
Equivalence Principle and high-redshift observations of quasar absorption
spectra consistent with time variations in the fine structure constant.


title: The Quasi-Holonomic Ansatz and Restricted Lattice Walks

abstract:
  The great enumerator Germain Kreweras empirically discovered this intriguing
fact, and then needed lots of pages[K], and lots of human ingenuity, to prove
it. Other great enumerators, for example, Heinrich Niederhausen[N], Ira
Gessel[G1], and Mireille Bousquet-M\'elou[B], found other ingenious,
``simpler'' proofs. Yet none of them is as simple as ours! Our proof (with the
generous help of our faithful computers) is ``ugly'' in the traditional sense,
since it would be painful for a lowly human to follow all the steps. But
according to our humble aesthetic taste, this proof is much more elegant, since
it is (conceptually) one-line. So what if that line is rather long (a huge
partial-recurrence equation satisfied by the general counting function), it
occupies less storage than a very low-resolution photograph.


title:
Gravitational Lenses in Generalized Einstein-Aether theory: the Bullet
  Cluster

abstract:
  We study the lensing properties of an asymmetric mass distribution and vector
field in Generalized Einstein-Aether (GEA) theory. As vector field fluctuations
are responsible in GEA for seeding baryonic structure formation, vector field
concentrations can exist independently of baryonic matter. Such concentrations
would not be expected to be tied to baryonic matter except gravitationally, and
so, like dark matter halos, would become separated from baryonic matter in
interacting systems such as the Bullet Cluster. These vector field
concentrations cause metric deviations that affect weak lensing. Therefore, the
distribution of weak lensing deviates from that which would be inferred from
the luminous mass distribution, in a way that numerical calculations
demonstrate can be consistent with observations. This suggests that
MOND-inspired theories can reproduce weak lensing observations, but makes clear
the price: the existence of a coherent large-scale fluctuation of a field(s)
weakly tied to the baryonic matter, not completely dissimilar to a dark matter
halo.


title:
Geodesic Properties and Orbits in 5-dimensional Hypercylindrical
  Spacetime

abstract:
  We investigate the geodesic motions of a massive particle and light ray in
the hyperplane orthogonal to the symmetry axis in the 5-dimensional
hypercylindrical spacetime. The class of the solutions depends on one constant
a which is the ratio of string mass density and tension. There exist unstable
orbits in null geodesic only in some range of a. The innermost stable circular
orbits in timelike geodesic also exist only in a certain range of the parameter
a. The capture cross section and the deflection angle of light ray are also
computed.


title:
Electrostatic and electrokinetic contributions to the elastic moduli of
  a driven membrane

abstract:
  We discuss the electrostatic contribution to the elastic moduli of a cell or
artificial membrane placed in an electrolyte and driven by a DC electric field.
The field drives ion currents across the membrane, through specific channels,
pumps or natural pores. In steady state, charges accumulate in the Debye layers
close to the membrane, modifying the membrane elastic moduli. We first study a
model of a membrane of zero thickness, later generalizing this treatment to
allow for a finite thickness and finite dielectric constant. Our results
clarify and extend the results presented in [D. Lacoste, M. Cosentino
Lagomarsino, and J. F. Joanny, Europhys. Lett., {\bf 77}, 18006 (2007)], by
providing a physical explanation for a destabilizing term proportional to
$\kps^3$ in the fluctuation spectrum, which we relate to a nonlinear ($E^2$)
electro-kinetic effect called induced-charge electro-osmosis (ICEO). Recent
studies of ICEO have focused on electrodes and polarizable particles, where an
applied bulk field is perturbed by capacitive charging of the double layer and
drives flow along the field axis toward surface protrusions; in contrast, we
predict "reverse" ICEO flows around driven membranes, due to curvature-induced
tangential fields within a non-equilibrium double layer, which hydrodynamically
enhance protrusions. We also consider the effect of incorporating the dynamics
of a spatially dependent concentration field for the ion channels.


title:
Study of tau- --> V P- nu(tau) in the framework of resonance chiral
  theory

abstract:
  In this paper we study two kinds of tau decays: (a) tau- --> (rho pi-,omega
pi-, phi pi-, K*0 K-) nu(tau), which belong to Delta S=0 processes and (b)
Delta S = 1 processes, like tau- --> (rho K-, omega K-, phi K-, \bar{K*0} pi-)
nu(tau), in the framework of resonance chiral theory. We fit the tau- --> omega
pi- nu(tau) spectral function and the invariant mass distribution of omega K in
the process of tau- --> omega K- nu(tau) to get the values of unknown resonance
couplings. Then we make a prediction for branching ratios of all channels.


title:
Electron Transport in Silicon Nanowires: The Role of Acoustic Phonon
  Confinement and Surface Roughness Scattering

abstract:
  We investigate the effects of electron and acoustic-phonon confinement on the
low-field electron mobility of thin square silicon nanowires (SiNWs) that are
surrounded by SiO$_2$ and gated. We employ a self-consistent
Poisson-Schr\"{o}dinger-Monte Carlo solver that accounts for scattering due to
acoustic phonons (confined and bulk), intervalley phonons, and the Si/SiO$_2$
surface roughness. The wires considered have cross sections between 3 $\times$
3 nm$^2$ and 8 $\times$ 8 nm$^2$. For larger wires, as expected, the dependence
of the mobility on the transverse field from the gate is pronounced. At low
transverse fields, where phonon scattering dominates, scattering from confined
acoustic phonons results in about a 10% decrease of the mobility with respect
to the bulk phonon approximation. As the wire cross-section decreases, the
electron mobility drops because the detrimental increase in both
electron--acoustic phonon and electron--surface roughness scattering rates
overshadows the beneficial volume inversion and subband modulation. For wires
thinner than 5 $\times$ 5 nm$^2$, surface roughness scattering dominates
regardless of the transverse field applied and leads to a monotonic decrease of
the electron mobility with decreasing SiNWs cross section.


title: Stimulated Raman Adiabatic Passage in Tm$^{3+}$:YAG

abstract:
  We report on the experimental demonstration of stimulated Raman adiabatic
passage (STIRAP) in a Tm$^{3+}$:YAG crystal. Tm$^{3+}$:YAG is a promising
material for use in quantum information processing applications, but as yet
there are few experimental investigations of coherent Raman processes in this
material. We investigate the effect of inhomogeneous broadening and Rabi
frequency on the transfer efficiency and the width of the two-photon spectrum.
Simulations of the complete Tm$^{3+}$:YAG system are presented along with the
corresponding experimental results.