title:
Retour sur les lingots de plomb de Comacchio (Ferrara, Italie) en
  passant par l'archeometrie et l'epigraphie

abstract:
  Up to now the origin of 102 lead ingots of the Comacchio (Ferrara, Italy)
relict, found in 1981, has been difficult to solve and different hypothesis
have been proposed. Recently 20 representative ingots have been analysed at the
European JRC Laboratory of Ispra(Italy) and the lead isotope signature
determined. From the performed results we may suggest the ores of
Cartagena-Mazarron or Sierra Almagrera (Sud-East of Spain) be the probable lead
origin of ingots. Archaeological examination and epigraphic arguments indicate
Cartagena-Mazarron as the most probable of the two mine regions. The role of
different persons, whose names are reported on the ingots, is discussed under a
commercial point of view. We try to understand the commercial travel of the
ship and the presence of the ingots in the Nord Adriatic sea.


title: Simulating geomagnetic reversals through 2D Ising systems

abstract:
  In this work 2D Ising systems were used to simulate the reversals of the
Earth's magnetic field. Each spin was supposed to be a ring current in the
Earth dynamo and the magnetization to be proportional to the field intensity.
Given the relative success of some physical few-discs modeling of this system
all the simulations were implemented in small systems. The temperature T was
used as a tunning parameter. It plays the role of external perturbations. Power
laws were obtained for the distribution of times between reversals. When the
system size was increased the exponent of the power law asymptotically tended
towards values very near -1.5, generally accepted as the right value for this
phenomenon. Depending on the proximity of T and Tc the average duration of
reversal period changes. In this way it is possible to establish a parallel
between the model and more or less well defined periods of the reversal record.
Some possible trends for future works are advanced.


title: Interference-filter-stabilized external-cavity diode lasers

abstract:
  We have developed external-cavity diode lasers, where the wavelength
selection is assured by a low loss interference filter instead of the common
diffraction grating. The filter allows a linear cavity design reducing the
sensitivity of the wavelength and the external cavity feedback against
misalignment. By separating the feedback and wavelength selection functions,
both can be optimized independently leading to an increased tunability of the
laser. The design is employed for the generation of laser light at 698, 780 and
852 nm. Its characteristics make it a well suited candidate for space-born
lasers.


title: Opto-fluidic third order distributed feed-back dye laser

abstract:
  This letter describes the design and operation of a polymer-based third order
distributed feed-back (DFB) microfluidic dye laser. The device relies on
light-confinement in a nano-structured polymer film where an array of
nanofluidic channels is filled by capillary action with a liquid dye solution
which has a refractive index lower than that of the polymer. In combination
with a third order DFB grating, formed by the array of nanofluidic channels,
this yields a low threshold for lasing. The laser is straight-forward to
integrate on Lab-on-a-Chip micro-systems where coherent, tunable light in the
visible range is desired.


title:
Influence of equation of state on interpretation of electrical
  conductivity measurements in strongly coupled tungsten plasma

abstract:
  We study the influence of equation-of-state (EOS) model on the interpretation
of electrical conductivity measurements in strongly coupled plasma of tungsten
by Korobenko et al. (2002 Plasma Physics Reports 28(12) 1008--1016). Three
different semiempirical EOS models for tungsten are used. Discrepancies in
obtained thermodynamic parameters and specific resistivity values as compared
with calculation results of Korobenko et al. are analysed.


title: Tunnel ionization of open-shell atoms

abstract:
  A generalized ADK (Ammosov-Delone-Krainov) theory for ionization of open
shell atoms is compared to ionization experiments performed on the transition
metal atoms V, Ni, Pd, Ta, and Nb. Our theory is found to be in good agreement
for V, Ni, Pd, and Ta, whereas conventional ADK theory overestimates ionization
by orders of magnitude. The key to understanding the observed ionization
reduction is the angular momentum barrier. Our analysis shows that the
determination of the angular momentum barrier in open shell atoms is
nontrivial. The Stark shift is identified as the second dominant effect
responsible for ionization suppression. Finally, these two effects cannot
explain the Nb data. An analysis of the electron spins suggests that Pauli
blocking might be responsible for the suppression of tunneling in Nb.


title: Humidity contribution to the refractive index structure function C_n^2

abstract:
  Humidity and C_n^2 data collected from the Chesapeake Bay area during the
2003/2004 period have been analyzed. We demonstrate that there is an
unequivocal correlation between the data during the same time periods, in the
absence of solar insolation. This correlation manifests itself as an inverse
relationship. We suggest that C_n^2 in the infrared region is also function of
humidity, in addition to temperature and pressure.


title:
Observation of X-rays generated by relativistic electrons in waveguide
  target mounted inside a betatron

abstract:
  In this work we have observed x-ray emission from x-ray waveguide radiator
excited by relativistic electrons. The experiment carried out at Tomsk betatron
B-35. Such new type stratified target was mounted on goniometer head inside the
betatron toroid. The target is consisted of the W-C-W layers placed on Si
substrate. The photographs of the angular distributions of the radiation
generated in the target by 20-33 MeV electrons have shown the waveguide effect
of the three-layer structure on x-rays generated in the target. The effect
proved in an angular distribution of radiation as an additional narrow peak of
guided x-rays intensity inside a wide cone of usual Bremsstrahlung.


title: Cooling in reduced period optical lattices: non-zero Raman detuning

abstract:
  In a previous paper [Phys. Rev. A 72, 033415 (2005)], it was shown that
sub-Doppler cooling occurs in a standing-wave Raman scheme (SWRS) that can lead
to reduced period optical lattices. These calculations are extended to allow
for non-zero detuning of the Raman transitions. New physical phenomena are
encountered, including cooling to non-zero velocities, combinations of Sisyphus
and "corkscrew" polarization cooling, and somewhat unusual origins of the
friction force. The calculations are carried out in a semi-classical
approximation and a dressed state picture is introduced to aid in the
interpretation of the results.


title:
Collective effects in intra-cellular molecular motor transport:
  coordination, cooperation and competetion

abstract:
  Molecular motors do not work in isolation {\it in-vivo}. We highlight some of
the coordinations, cooperations and competitions that determine the collective
properties of molecular motors in eukaryotic cells. In the context of
traffic-like movement of motors on a track, we emphasize the importance of
single-motor bio-chemical cycle and enzymatic activity on their collective
spatio-temporal organisation. Our modelling strategy is based on a synthesis-
the same model describes the single-motor mechano-chemistry at sufficiently low
densities whereas at higher densities it accounts for the collective flow
properties and the density profiles of the motors. We consider two specific
examples, namely, traffic of single-headed kinesin motors KIF1A on a
microtubule track and ribosome traffic on a messenger RNA track.


title: Geographical networks evolving with optimal policy

abstract:
  In this article, we propose a growing network model based on an optimal
policy involving both topological and geographical measures. In this model, at
each time step, a new node, having randomly assigned coordinates in a $1 \times
1$ square, is added and connected to a previously existing node $i$, which
minimizes the quantity $r_i^2/k_i^\alpha$, where $r_i$ is the geographical
distance, $k_i$ the degree, and $\alpha$ a free parameter. The degree
distribution obeys a power-law form when $\alpha=1$, and an exponential form
when $\alpha=0$. When $\alpha$ is in the interval $(0,1)$, the network exhibits
a stretched exponential distribution. We prove that the average topological
distance increases in a logarithmic scale of the network size, indicating the
existence of the small-world property. Furthermore, we obtain the geographical
edge-length distribution, the total geographical length of all edges, and the
average geographical distance of the whole network. Interestingly, we found
that the total edge-length will sharply increase when $\alpha$ exceeds the
critical value $\alpha_c=1$, and the average geographical distance has an upper
bound independent of the network size. All the results are obtained
analytically with some reasonable approximations, which are well verified by
simulations.


title:
Radiation enhancement and radiation suppression by a left-handed
  metamaterial

abstract:
  The perfect lens property of a dispersive and lossy left-handed metamaterial
(LHM) disk is exploited to superimpose a source of electromagnetic radiation
onto its mirror image, formed as a result of reflection from a perfect electric
conductor (PEC) or a perfect magnetic conductor (PMC). The superposition of a
vertical wire-dipole antenna with its PEC-image results in an increase of the
radiation resistance of the antenna compared to that of an antenna emitting in
free space. On the other hand, if the same antenna is coupled to a PMC-image it
is shown that the result is the formation of a non-radiating configuration. The
finite-difference time-domain (FDTD) analysis is performed and this allows a
detailed characterization of the systems. It is shown that the non-radiating
system allows relatively large amounts of electromagnetic energy to be stored
in the LHM-disk and that is indicative of strong electromagnetic fields inside
the material. This property is employed in a second-harmonic generation (SHG)
process and the potential of a non-radiating configuration as an efficient
nonlinear device is demonstrated.


title:
The study of synchronous (by local time) changes of the statistical
  properties of thermal noise and alpha-activity fluctuations of a 239-Pu
  sample

abstract:
  Experimentally obtained and analyzed fine structure of statistical
distributions for two physically independent processes: alpha-decay rate
fluctuations of Pu-239 sample in Pushchino (Moscow region, Russia) and
equilibrium voltage fluctuations (Johnson noise) from metal-film resistor in
Tbilisi (Georgia). Special investigation of histograms shape similarity in
these processes demonstrated majority of previously studied effects, called -
macroscopic fluctuations. Offered qualitative model of the observed effects.


title: Test problems in mechanics and special relativity

abstract:
  These test problems were used by the author as weekly control works for the
first year physics students at Novosibirsk State University in 2005. Solutions
of the problems are also given. The problems were taken from or inspired by the
sources listed at the end.


title:
A set of basis functions to improve numerical calculation of Mie
  scattering in the Chandrasekhar-Sekera representation

abstract:
  Numerical calculations of light propagation in random media demand the
multiply scattered Stokes intensities to be written in a common fixed
reference. A particularly useful way to perform automatically these basis
transformations is to write the scattered intensities in the
Chandrasekhar-Sekera representation. This representation produces side effects
so that numerical tests are necessary to deal with the limiting situations of
the small-particle (Rayleigh) and forward/backward scattering. Here a new set
of basis functions is presented to describe the scattering of light by
spherical particles (Mie scattering) in the Chandrasekhar-Sekera
representation. These basis functions can be implemented in a new algorithm to
calculate the Mie scattering amplitudes, which leads straightforwardly to all
the scattering quantities. In contrast to the traditional implementation, this
set of basis functions implies to natural numerical convergence to the above
mentioned limiting cases, which are thoroughly discussed.

categories: physics.optics math-ph math.MP physics.comp-ph


title:
Applying the Hilbert--Huang Decomposition to Horizontal Light
  Propagation C_n^2 data

abstract:
  The Hilbert Huang Transform is a new technique for the analysis of
non--stationary signals. It comprises two distinct parts: Empirical Mode
Decomposition (EMD) and the Hilbert Transform of each of the modes found from
the first step to produce a Hilbert Spectrum. The EMD is an adaptive
decomposition of the data, which results in the extraction of Intrinsic Mode
Functions (IMFs). We discuss the application of the EMD to the calibration of
two optical scintillometers that have been used to measure C_n^2 over
horizontal paths on a building rooftop, and discuss the advantage of using the
Marginal Hilbert Spectrum over the traditional Fourier Power Spectrum.


title:
Covariant Formulation of the Dynamics in a Dissipative Dielectric
  Obtained from a Simplified Lagrangian

abstract:
  Equations of motions and energy-momentum density tensors are obtained for a
dispersive and dissipative medium sustaining electric and magnetic
polarizations, using Lagrangian formalisms. A previous work on the subject by
the authors has been simplified by reduction in the Lagrangian of the number of
independent vector fields, with which the sink modes (associated with the
dissipation) interact. The paper also formulates the dynamics of the
electromagnetic field in the medium in a covariant (relativistic) manner. We
discuss (and compare) the results, especially from the point of view of the
positivity of the energy density.


title: A Few Comments on Classical Electrodynamics

abstract:
  In this article we will discuss a few aspects of the spacetime description of
matter and fields. In Section:1 we will discuss the completeness of real
numbers in the context of an alternate definition of the straight line as a
geometric continuum. According to this definition, points are not regarded as
the basic constituents of a line segment and a line segment is considered to be
a fundamental geometric object. This definition is in particular suitable to
coordinatize different points on the straight line preserving the order
properties of real numbers. Geometrically fundamental nature of line segments
are required in physical theories like the string theory. We will discuss the
cardinality of rational numbers in the later half of Section:1. We will first
discuss what we do in an actual process of counting and define functions
well-defined on the set of all positive integers. We will follow an alternate
approach that depends on the Hausdorff topology of real numbers to demonstrate
that the set of positive rationals can have a greater cardinality than the set
of positive integers. This approach is more consistent with an actual act of
counting. This article indicates that the axiom of choice can be a better
technique to prove theorems that use second-countability. This is important for
the metrization theorems and physics of spacetime. In Section:2 we will discuss
an improved proof of the Poisson's equation. We will show that the self energy
of a point charge can be zero in the potential approach to evaluate it. In
Section:3 we will discuss a few aspects of the equivalence of the Schwarzschild
coordinates and the Kruskal-Szekeres coordinates. In Section:4 we will make a
few comments on general physics including the special theory of relativity and
hydrodynamics.


title: Non-Newtonian thin films with normal stresses: dynamics and spreading

abstract:
  The dynamics of thin films on a horizontal solid substrate is investigated in
the case of non-Newtonian fluids exhibiting normal stress differences, the
rheology of which is strongly non-linear. Two coupled equations of evolution
for the thickness of the film and the shear rate are proposed within the
lubrication approximation. This framework is applied to the motion of an
advancing contact line. The apparent dynamic contact angle is found to depend
logarithmically on a lengthscale determined solely by the rheological
properties of the fluid and the velocity of the contact line.


title: Concepts, Developments and Advanced Applications of the PAX Toolkit

abstract:
  The Physics Analysis eXpert (PAX) is an open source toolkit for high energy
physics analysis. The C++ class collection provided by PAX is deployed in a
number of analyses with complex event topologies at Tevatron and LHC. In this
article, we summarize basic concepts and class structure of the PAX kernel. We
report about the most recent developments of the kernel and introduce two new
PAX accessories. The PaxFactory, that provides a class collection to facilitate
event hypothesis evolution, and VisualPax, a Graphical User Interface for PAX
objects.


title: Cosmo-physical effects in the time series of the GCP network

abstract:
  In the GCP network, an Internet system of noise generators developed under
the direction of Prof. R. Nelson and deployed at various geographical points,
synchronous measurements of a priori random noise processes are carried out
every second. The time series obtained in these measurements are "quite random"
from the viewpoint of traditional methods of statistical analysis. However, as
shown in our works, using the method of histogram comparison allows one to
discover clear regularities in the noise processes of any nature, from
biochemical reactions to radioactive decay or noise in the gravitational
antenna. These regularities cannot be revealed by the traditional methods of
time series analysis and seem to be determined by fluctuations of the
space-time, which result from the movement of the "laboratory" relative to the
mass thicknesses (celestial bodies). The application of this method to the
analysis of time series of the GCP system showed all the main regularities
described earlier: the histogram pattern changes with well-resolved sidereal
and solar daily periods; at different geographical points, similar histogram
patterns are highly probable to appear at the same local time; histograms with
a specific "eclipse" pattern appear synchronously "all over the Earth" at the
moments of culmination of a solar eclipse.


title:
Predictability, Risk and Online Management in a Complex System of
  Adaptive Agents

abstract:
  We discuss the feasibility of predicting, managing and subsequently
manipulating, the future evolution of a Complex Adaptive System. Our archetypal
system mimics a population of adaptive, interacting objects, such as those
arising in the domains of human health and biology (e.g. cells), financial
markets (e.g. traders), and mechanical systems (e.g. robots). We show that
short-term prediction yields corridors along which the model system will, with
high probability, evolve. We show how the widths and average direction of these
corridors varies in time as the system passes through regions, or pockets, of
enhanced predictability and/or risk. We then show how small amounts of
'population engineering' can be undertaken in order to steer the system away
from any undesired regimes which have been predicted. Despite the system's many
degrees of freedom and inherent stochasticity, this dynamical, 'soft' control
over future risk requires only minimal knowledge about the underlying
composition of the constituent multi-agent population.


title: Monte Carlo simulation of survival for minority languages

abstract:
  Our earlier language model is modified to allow for the survival of a
minority language without higher status, just because of the pride of its
speakers in their linguistic identity. An appendix studies the roughness of the
interface for linguistic regions when one language conquers the whole
territory.


title:
Interpretation of the slight periodic displacement in the
  Michelson-Morley experiments

abstract:
  The slight periodic displacements in the Michelson-Morley interference
experiments do not show ether-drift; however, they do show the effects of the
theory of general relativity that is, the effects of acceleration and
deceleration to the interference condition of the Michelson-Morley interference
experiments. Therefore, these slight periodic variations are very significant
and important for strengthening the theory of special and general relativity.
The slight periodic displacements are discussed from the viewpoint of the
theories of general relativity and interference.


title: Quantum mechanics from a universal action reservoir

abstract:
  A heuristic derivation of quantum mechanics using information theory requires
a foundational physical principle: the existence of a universal action
reservoir, analogous to the energy reservoir of a canonical ensemble.


title: Poincare's relativistic Doppler-Fizeau formula

abstract:
  We deduce from Poincare's ellipsoidal wavefronts a relativistic
Doppler-Fizeau formula that is not the same as 1905 Einstein's one.
Longitudinally, Einstein's formula and Poincare's formula are the same. The
question of an experimental test is connected with the possibility or the
impossibility of directly measuring the relativistic transverse effect.
Hasselkamp's 1978 experiment becomes a crucial experiment because Poincare's
relativistic kinematics predicts an expansion of sapce directly connected with
the Doppler-Fizeau effect for the remote objects.


title: Efficiency of pair formation in a model society

abstract:
  In a recent paper a set of differential equations was proposed to describe a
social process, where pairs of partners emerge in a community. The choice was
performed on a basis of attractive resources and of random initial preferences.
An efficiency of the process, defined as the probability of finding a partner,
was found to depend on the community size. Here we demonstrate, that if the
resources are not relevant, the efficiency is equal to unity; everybody finds a
partner. With this new formulation, about 80 percent of community members enter
to dyads; the remaining 20 percent form triads.


title: Network properties of written human language

abstract:
  We investigate the nature of written human language within the framework of
complex network theory. In particular, we analyse the topology of Orwell's
\textit{1984} focusing on the local properties of the network, such as the
properties of the nearest neighbors and the clustering coefficient. We find a
composite power law behavior for both the average nearest neighbor's degree and
average clustering coefficient as a function of the vertex degree. This implies
the existence of different functional classes of vertices. Furthermore we find
that the second order vertex correlations are an essential component of the
network architecture. To model our empirical results we extend a previously
introduced model for language due to Dorogovtsev and Mendes. We propose an
accelerated growing network model that contains three growth mechanisms: linear
preferential attachment, local preferential attachment and the random growth of
a pre-determined small finite subset of initial vertices. We find that with
these elementary stochastic rules we are able to produce a network showing
syntactic-like structures.


title: Complexities of social networks: A Physicist's perspective

abstract:
  The review is a survey of the present status of research in social networks
highlighting the topics of small world property, degree distributions,
community structure, assortativity, modelling, dynamics and searching in social
networks.


title:
Design, fabrication and characterisation of InGaAs/InP single-photon
  avalanche diode detectors

abstract:
  This paper demonstrates the performance of planar geometry InGaAs/InP
avalanche diodes, specifically designed and fabricated for Geiger-mode
operation at wavelengths around 1550nm, in terms of dark count rate,
single-photon detection efficiency, afterpulsing and photon-timing jitter.


title: A PMT-Block test bench

abstract:
  The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is
housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument
comprising a light mixer, a PMT together with its divider and a {\it 3-in-1}
card, which provides shaping, amplification and integration for the signals.
This instrument needs to be qualified before being assembled on the detector. A
PMT-Block test bench has been developed for this purpose. This test bench is a
system which allows fast, albeit accurate enough, measurements of the main
properties of a complete PMT-Block. The system, both hardware and software, and
the protocol used for the PMT-Blocks characterisation are described in detail
in this report. The results obtained in the test of about 10000 PMT-Blocks
needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile
Calorimeter are also reported.


title:
Quantum electrodynamic corrections to the hyperfine structure of excited
  S states

abstract:
  State-dependent quantum electrodynamic corrections are evaluated for the
hyperfine splitting of nS states for arbitrary principal quantum number n. The
calculations comprise both the self-energy and the vacuum-polarization
correction of order alpha(Z alpha)^2 E_F and the recoil correction of order (Z
alpha)^2 (m/M) E_F. Higher-order corrections are summarized and partly
reevaluated as well. Accurate predictions for hydrogen hyperfine splitting
intervals of nS states with n=2,...,8 are presented. The results obtained are
important due to steady progress in hydrogen spectroscopy for transitions
involving highly excited S states.


title: The vacuum state of quantum gravity contains large virtual masses

abstract:
  In the functional integral approach to quantum gravity, the quantum
configurations are usually treated to order hbar through a stationary phase
approximation around the saddle point of the action where spacetime is flat. We
show that from this point a "level line" in functional space departs, which
comprises a family of static non-flat metrics with zero scalar curvature,
depending on a continuous mass parameter. Furthermore, each of these metrics
can be perturbed by an arbitrary function in such a way to still satisfy the
condition Int(gR)d4x=0. We thus find a set of zero-modes of the gravitational
action which has non-vanishing measure in the functional space. These metrics
will contribute to the functional integral as vacuum fluctuations, on the same
footing as those near the saddle point.


title: Ising Ferromagnet: Zero-Temperature Dynamic Evolution

abstract:
  The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a
square lattice is followed by Monte Carlo computer simulations. The system
always eventually reaches a final, absorbing state, which sometimes coincides
with a ground state (all spins parallel), and sometimes does not (parallel
stripes of spins up and down). We initiate here the numerical study of
``Chaotic Time Dependence'' (CTD) by seeing how much information about the
final state is predictable from the randomly generated quenched initial state.
CTD was originally proposed to explain how nonequilibrium spin glasses could
manifest equilibrium pure state structure, but in simpler systems such as
homogeneous ferromagnets it is closely related to long-term predictability and
our results suggest that CTD might indeed occur in the infinite volume limit.


title: The Issue of the Beginning in Quantum Gravity

abstract:
  The goal of this report is to provide an up to date account of results on the
quantum nature of the big bang, obtained in loop quantum cosmology. They
suggest a radical modification of the paradigm provided by general relativity
for the issue of the Beginning. The article is addressed primarily to
historians and philosophers of science.


title: Quantum mechanism of Biological Search

abstract:
  We wish to suggest an algorithm for biological search including DNA search.
Our argument supposes that biological search be performed by quantum search.If
we assume this, we can naturally answer the following long lasting puzzles such
that "Why does DNA use the helix structure?" and "How can the evolution in
biological system occur?".


title: Ion-aerosol interactions in the lower atmosphere of Venus

abstract:
  All planetary atmospheres are electrified to some extent by cosmic ray
ionisation, and Venus is no exception. There is increasing awareness that
ion-aerosol interactions could modulate terrestial radiative processes, and
this possibility will be investigated for the Venusian atmosphere. The
likelihood of a Venusian global atmospheric electric circuit will also be
discussed.


title:
Field-induced phases of an orientable charged particle in a dilute
  background of point charges

abstract:
  We study a dynamical model of a rod-like particle surrounded by a cloud of
smaller particles of the same charge and we show that, in the presence of a
low-frequency alternating electric field, the rod displays the same type of
anomalous orientation (perpendicular to the field) that was recently observed
in laboratory colloids. This indicates that the anomalous orientation is due to
the collective dynamics of the colloidal particles, and does not require
electro-osmotic effects. We also confirm the experimental observation that for
higher field frequencies the standard orientation (parallel to the field)
prevails. In the simulations, these changes are abrupt enough to resemble a
phase transition.


title:
The Coulomb four-body problem in a classical framework: Triple
  photoionization of lithium

abstract:
  Formulating a quasiclassical approach we determine the cross section for the
complete four-body break-up of the lithium ground state following single photon
absorption from threshold up to 220 eV excess energy. In addition, we develop a
new classification scheme for three-electron ionizing trajectories in terms of
electron-electron collisions, thereby identifying two main ionization paths
which the three electrons in the ground state of lithium follow to escape to
the continuum. The dominant escape paths manifest themselves in a
characteristic ``T-shape'' break-up pattern of the three electrons which
implies observable structures in the electronic angular correlation
probability. This break-up pattern prevails for excess energies so low that the
Wannier threshold law $\sigma\propto E^{\alpha}$ describes already the triple
ionization cross section, whose predicted value $\alpha=2.16$ we can confirm
quantitatively.


title:
Anomalous propagations of electromagnetic waves in anisotropic media
  with a unique dispersion relation

abstract:
  We investigate the reflection and refraction behaviors of electromagnetic
waves at the interface between an isotropic material and the anisotropic medium
with a unique dispersion relation. We show that the refraction angle of whether
phase or energy flow for $E$-polarized waves is opposite to that for
$H$-polarized waves, though the dispersion relations for $E$- and $H$-polarized
waves are the same in such anisotropic media. For a certain polarized wave the
refraction behaviors of wave vector and energy flow are also significantly
different. It is found that waves exhibit different propagation behaviors in
anisotropic media with different sign combinations of the permittivity and
permeability tensors. Some interesting properties of propagation are also found
in the special anisotropic media, such as amphoteric refraction, oblique total
transmission for both $E$- and $H$-polarized waves, and the inversion of
critical angle. The special anisotropic media can be realized by metamaterials
and lead to potential applications, such as to fabricate polarization splitters
with higher efficiencies than conventional counterparts.


title: Space Charges Can Significantly Affect the Dynamics of Accelerator Maps

abstract:
  Space charge effects can be very important for the dynamics of intense
particle beams, as they repeatedly pass through nonlinear focusing elements,
aiming to maximize the beam's luminosity properties in the storage rings of a
high energy accelerator. In the case of hadron beams, whose charge distribution
can be considered as "frozen" within a cylindrical core of small radius
compared to the beam's dynamical aperture, analytical formulas have been
recently derived \cite{BenTurc} for the contribution of space charges within
first order Hamiltonian perturbation theory. These formulas involve
distribution functions which, in general, do not lead to expressions that can
be evaluated in closed form. In this paper, we apply this theory to an example
of a charge distribution, whose effect on the dynamics can be derived
explicitly and in closed form, both in the case of 2--dimensional as well as
4--dimensional mapping models of hadron beams. We find that, even for very
small values of the "perveance" (strength of the space charge effect) the long
term stability of the dynamics changes considerably. In the flat beam case, the
outer invariant "tori" surrounding the origin disappear, decreasing the size of
the beam's dynamical aperture, while beyond a certain threshold the beam is
almost entirely lost. Analogous results in mapping models of beams with
2-dimensional cross section demonstrate that in that case also, even for weak
tune depressions, orbital diffusion is enhanced and many particles whose motion
was bounded now escape to infinity, indicating that space charges can impose
significant limitations on the beam's luminosity.


title:
Educational studies of cosmic rays with telescope of Geiger-Muller
  counters

abstract:
  A group of high school students (XII Liceum) in the framework of the Roland
Maze Project has built a compact telescope of three Geiger-Muller counters. The
connection between the telescope and PC computer was also created and programed
by students involved in the Project. This has allowed students to use their
equipment to perform serious scientific measurements concerning the single
cosmic ray muon flux at ground level and below. These measurements were then
analyzed with the programs based on the 'nowadays' knowledge on statistics. An
overview of the apparatus, methods and results were presented at several
students conferences and recently won the first prize in a national competition
of high school students scientific work. The telescope itself, in spite of its
'scientific' purposes, is built in such a way that it is hung on a wall in a
school physics lab and counts muons continuously. This can help to raise the
interest for studying physics among others. At present a few (3) groups of
young participants of the Roland Maze Project have already built their own
telescopes for their schools and some others are working on it. This work is a
perfect example of what can be done by young people when respective
opportunities are created by more experienced researchers and a little help and
advice is given.


title:
Estimates for the two-dimensional Navier-Stokes equations in terms of
  the Reynolds number

abstract:
  The tradition in Navier-Stokes analysis of finding estimates in terms of the
Grashof number $\bG$, whose character depends on the ratio of the forcing to
the viscosity $\nu$, means that it is difficult to make comparisons with other
results expressed in terms of Reynolds number $\Rey$, whose character depends
on the fluid response to the forcing. The first task of this paper is to apply
the approach of Doering and Foias \cite{DF} to the two-dimensional
Navier-Stokes equations on a periodic domain $[0,L]^{2}$ by estimating
quantities of physical relevance, particularly long-time averages
$\left<\cdot\right>$, in terms of the Reynolds number $\Rey = U\ell/\nu$, where
$U^{2}= L^{-2}\left<\|\bu\|_{2}^{2}\right>$ and $\ell$ is the forcing scale. In
particular, the Constantin-Foias-Temam upper bound \cite{CFT} on the attractor
dimension converts to $a_{\ell}^{2}\Rey(1 + \ln\Rey)^{1/3}$, while the estimate
for the inverse Kraichnan length is $(a_{\ell}^{2}\Rey)^{1/2}$, where
$a_{\ell}$ is the aspect ratio of the forcing. Other inverse length scales,
based on time averages, and associated with higher derivatives, are estimated
in a similar manner. The second task is to address the issue of intermittency :
it is shown how the time axis is broken up into very short intervals on which
various quantities have lower bounds, larger than long time-averages, which are
themselves interspersed by longer, more quiescent, intervals of time.


title:
Finding community structure in networks using the eigenvectors of
  matrices

abstract:
  We consider the problem of detecting communities or modules in networks,
groups of vertices with a higher-than-average density of edges connecting them.
Previous work indicates that a robust approach to this problem is the
maximization of the benefit function known as "modularity" over possible
divisions of a network. Here we show that this maximization process can be
written in terms of the eigenspectrum of a matrix we call the modularity
matrix, which plays a role in community detection similar to that played by the
graph Laplacian in graph partitioning calculations. This result leads us to a
number of possible algorithms for detecting community structure, as well as
several other results, including a spectral measure of bipartite structure in
networks and a new centrality measure that identifies those vertices that
occupy central positions within the communities to which they belong. The
algorithms and measures proposed are illustrated with applications to a variety
of real-world complex networks.


title: MINERvA: a dedicated neutrino scattering experiment at NuMI

abstract:
  MINERvA is a dedicated neutrino cross-section experiment planned for the near
detector hall of the NuMI neutrino beam at Fermilab. I summarize the detector
design and physics capabilities of the experiment.


title: Two-Color Fabry-Perot Laser Diode with THz Primary Mode Spacing

abstract:
  A class of multiwavelength Fabry-Perot lasers is introduced where the
spectrum is tailored through a non-periodic patterning of the cavity effective
index. The cavity geometry is obtained using an inverse scattering approach and
can be designed such that the spacing of discrete Fabry-Perot lasing modes is
limited only by the bandwidth of the inverted gain medium. A specific two-color
semiconductor laser with a mode spacing in the THz regime is designed, and
measurements are presented demonstrating the simultaneous oscillation of the
two wavelengths. The extension of the Fabry-Perot laser concept described
presents significant new possibilities in laser cavity design.


title: Energy and enstrophy dissipation in steady state 2-d turbulence

abstract:
  Upper bounds on the bulk energy dissipation rate $\epsilon$ and enstrophy
dissipation rate $\chi$ are derived for the statistical steady state of body
forced two dimensional turbulence in a periodic domain. For a broad class of
externally imposed body forces it is shown that $\epsilon \le k_{f} U^3
Re^{-1/2}(C_1+C_2 Re^{-1})^{1/2}$ and $\chi \le k_{f}^{3}U^3 (C_1+C_2 Re^{-1})$
where $U$ is the root-mean-square velocity, $k_f$ is a wavenumber (inverse
length scale) related with the forcing function, and $Re = U /\nu k_f$. The
positive coefficients $C_1$ and $C_2$ are uniform in the the kinematic
viscosity $\nu$, the amplitude of the driving force, and the system size. We
compare these results with previously obtained bounds for body forces involving
only a single length scale, or for velocity dependent a constant-energy-flux
forces acting at finite wavenumbers. Implications of our results are discussed.


title: Effect of a thin optical Kerr medium on a Laguerre-Gaussian beam

abstract:
  Using a generalized Gaussian beam decomposition method we determine the
propagation of a Laguerre-Gaussian beam that has passed through a thin
nonlinear optical Kerr medium. The orbital angular momentum per photon of the
beam is found to be conserved while the component beams change. As an
illustration of applications, we propose and demonstrate a z-scan experiment
using an $LG_0^1$ beam and a dye-doped polymer film.


title:
Diffuse reflection of a Bose-Einstein condensate from a rough evanescent
  wave mirror

abstract:
  We present experimental results showing the diffuse reflection of a
Bose-Einstein condensate from a rough mirror, consisting of a dielectric
substrate supporting a blue-detuned evanescent wave. The scattering is
anisotropic, more pronounced in the direction of the surface propagation of the
evanescent wave. These results agree very well with theoretical predictions.


title:
Focusing and phase compensation of paraxial beams by a left-handed
  material slab

abstract:
  On the basis of angular spectrum representation, a formalism describing
paraxial beams propagating through an isotropic left-handed material (LHM) slab
is presented. The treatment allows us to introduce the ideas of beam focusing
and phase compensation by LHM slab. Because of the negative refractive index of
LHM slab, the inverse Gouy phase shift and the negative Rayleigh length of
paraxial Gaussian beam are proposed. It is shown that the phase difference
caused by the Gouy phase shift in right-handed material (RHM) can be
compensated by that caused by the inverse Gouy phase shift in LHM. If certain
matching conditions are satisfied, the intensity and phase distributions at
object plane can be completely reconstructed at the image plane.


title:
An Extended Interpretation of the Thermodynamic Theory Including an
  Additional Energy Associated with a Decrease in Mass

abstract:
  Although its practical efficiency is unquestionable, the thermodynamic tool
presents a slight inconsistency from the theoretical point of view. After
exposing arguments, which explain this opinion, a suggestion is put forward to
solve the problem. It consists of linking the mass-energy relation d m = m
c^{2} to the laws of thermodynamics. This combination results in a
clarification of the theory and opens a bridge between thermodynamics and
gravitation. It is shown that the submicroscopic consideration, which is based
on the cellular concept of the real physical space when the space is treated as
the tessellation lattice, indeed strongly supports the idea of a variation in
mass in thermodynamic processes.


title:
Modelling and Simulations of Multi-component Lipid Membranes and Open
  Membranes via Diffusive Interface Approaches

abstract:
  In this paper, phase field models are developed for multi-component vesicle
membranes with different lipid compositions and membranes with free boundary.
These models are used to simulate the deformation of membranes under the
elastic bending energy and the line tension energy with prescribed volume and
surface area constraints. By comparing our numerical simulations with recent
experiments, it is demonstrated that the phase field models can capture the
rich phenomena associated with the membrane transformation, thus it offers
great functionality in the simulation and modeling of multicomponent membranes.


title:
The Fermi Paradox in the light of the Inflationary and Brane World
  Cosmologies

abstract:
  The Fermi Paradox is discussed in the light of the inflationary and brane
world cosmologies. We conclude that some brane world cosmologies may be of
relevance for the problem of civilizations spreading across our galaxy,
strengthening the Fermi Paradox, but not the inflationary cosmologies, as has
been proposed.

categories: physics.pop-ph astro-ph gr-qc hep-th physics.space-ph


title: Divergent Time Scale in Axelrod Model Dynamics

abstract:
  We study the evolution of the Axelrod model for cultural diversity. We
consider a simple version of the model in which each individual is
characterized by two features, each of which can assume q possibilities. Within
a mean-field description, we find a transition at a critical value q_c between
an active state of diversity and a frozen state. For q just below q_c, the
density of active links between interaction partners is non-monotonic in time
and the asymptotic approach to the steady state is controlled by a time scale
that diverges as (q-q_c)^{-1/2}.


title: Sandage versus Hubble on the reality of the expanding universe

abstract:
  A critical reading of Lubin & Sandage's 2001 paper on the Tolman effect for
the reality of the expansion of the universe clearly reveals that Sandage is
far from winning the dispute with Hubble on the issue. After all the years,
Hubble's doubt about the reality of the expansion remains as valid as Sandage's
certainty expressed in a series of papers in the last decade.


title: Quantum Semiotics: A Sign Language for Quantum Mechanics

abstract: The article is taken out for change of contents with immediate effect.


title:
Reflection of light from a moving mirror: derivation of the relativistic
  Doppler formula without Lorentz transformations

abstract:
  A special case of the relativistic Doppler effect, which occurs when light
reflects from a moving mirror, is discussed. The classic formula for the
Doppler shift is derived in a fully non-relativistic fashion using basic facts
from geometry. The derivation does not involve Lorentz transformations, length
contractions and time dilations, and therefore is conceptually simpler than the
standard derivations in physics textbooks. This discussion can be useful for
teaching introductory physics and also for understanding the foundations of
special relativity.


title: Nonequilibrium Approach to Bloch-Peierls-Berry Dynamics

abstract:
  We examine the Bloch-Peierls-Berry dynamics under a classical nonequilibrium
dynamical formulation. In this formulation all coordinates in phase space
formed by the position and crystal momentum space are treated on equal footing.
Explicitly demonstrations of the no (naive) Liouville theorem and of the
validity of Darboux theorem are given. The explicit equilibrium distribution
function is obtained. The similarities and differences to previous approaches
are discussed. Our results confirm the richness of the Bloch-Peierls-Berry
dynamics.


title:
Quantitative and Qualitative Study of Gaussian Beam Visualization
  Techniques

abstract:
  We present a comparative overview of existing laser beam profiling methods.
We compare the the knife-edge, scanning slit, and pin-hole methods. Data is
presented in a comparative fashion. We also elaborate on the use of CCD
profiling methods and present appropriate imagery. These methods allow for a
quantitative determination of transverse laser beam-profiles using inexpensive
and accessible methods. The profiling techniques presented are inexpensive and
easily applicable to a variety of experiments.


title: Correlated non-perturbative electron dynamics with quantum trajectories

abstract:
  An approach to electron correlation effects in atoms that uses quantum
trajectories is presented. A comparison with the exact quantum mechanical
results for 1D Helium atom shows that the major features of the correlated
ground state distribution and of the strong field ionization dynamics are
reproduced with quantum trajectories. The intra-atomic resonant transitions are
described accurately by a trajectory ensemble. The present approach reduces
significantly the computational time and it can be used for both bound and
ionizing electrons.


title: Towards grid-enabled telemedicine in Africa

abstract:
  Telemedicine services are very relevant tools to train local physicians and
to improve diagnosis by exchanging medical data. Telemedicine networks allow
these exchanges but the set-up of multipoint dynamic telemedicine requires
moving towards GRID technologies. A healthgrid is an environment where data of
medical interest can be stored and is easily available between the different
actors of healthcare. Two telemedicine applications were developed to link
physicians from Burkina Faso and France with the perspective of setting up a
grid infrastructure between the participating medical sites. A web site to
exchange diagnosis on diabetic retinopathy was developed in PHP and another
application using web services was developed to exchange patient information
between two databases.


title: Superstring theories

abstract:
  We briefly review superstring theories, highlighting the important concepts,
developments, and open problems of the subject.


title:
Consequences of Symmetries on the Analysis and Construction of
  Turbulence Models

abstract:
  Since they represent fundamental physical properties in turbulence
(conservation laws, wall laws, Kolmogorov energy spectrum, ...), symmetries are
used to analyse common turbulence models. A class of symmetry preserving
turbulence models is proposed. This class is refined such that the models
respect the second law of thermodynamics. Finally, an example of model
belonging to the class is numerically tested.


title: Duality : A Bridge Between Physics And Philosophy?

abstract:
  A generalized view of Duality is offered as a bridge between physical
sciences and the more abstract philosophical dimensions bordering on mysticism.
To that end several examples of duality are first cited from from conventional
physics sectors to illustrate the obvious powers of this principle. These
include items from reciprocity in Newtonian mechanics to the problem of
measurement duality that characterizes quantum mechanics. It is also noted that
the latter has acquired a renewed interest in recent times, consequent on the
emergence of new experimental techniques for testing the actual laboratory
outcomes of traditional gedanken experiments, hitherto taken for granted.
Against this background, the Duality principle is sought to be extended to the
mystical domain, with convincing examples from various human level experiences.


title: Stochastic Simulations on the Cellular Wave Computers

abstract:
  The computational paradigm represented by Cellular Neural/nonlinear Networks
(CNN) and the CNN Universal Machine (CNN-UM) as a Cellular Wave Computer, gives
new perspectives for computational physics. Many numerical problems and
simulations can be elegantly addressed on this fully parallelized and analogic
architecture. Here we study the possibility of performing stochastic
simulations on this chip. First a realistic random number generator is
implemented on the CNN-UM, and then as an example the two-dimensional Ising
model is studied by Monte Carlo type simulations. The results obtained on an
experimental version of the CNN-UM with 128 * 128 cells are in good agreement
with the results obtained on digital computers. Computational time measurements
suggests that the developing trend of the CNN-UM chips - increasing the lattice
size and the number of local logic memories - will assure an important
advantage for the CNN-UM in the near future.


title:
Thin film dynamics on a vertically rotating disk partially immersed in a
  liquid bath

abstract:
  The axisymmetric flow of a thin liquid film is considered for the problem of
a vertically rotating disk that is partially immersed in a liquid bath. A model
for the fully three-dimensional free-boundary problem of the rotating disk,
that drags a thin film out of the bath is set up. From this, a
dimension-reduced extended lubrication approximation that includes the meniscus
region is derived. This problem constitutes a generalization of the classic
drag-out and drag-in problem to the case of axisymmetric flow. The resulting
nonlinear fourth-order partial differential equation for the film profile is
solved numerically using a finite element scheme. For a range of parameters
steady states are found and compared to asymptotic solutions. Patterns of the
film profile, as a function of immersion depth and angular velocity are
discussed.


title:
Interference of diffraction and transition radiation and its application
  as a beam divergence diagnostic

abstract:
  We have observed the interference of optical diffraction radiation (ODR) and
optical transition radiation (OTR) produced by the interaction of a
relativistic electron beam with a micromesh foil and a mirror. The production
of forward directed ODR from electrons passing through the holes and wires of
the mesh and their separate interactions with backward OTR from the mirror are
analyzed with the help of a simulation code. By careful choice of the micromesh
properties, mesh-mirror spacing, observation wavelength and filter band pass,
the interference of the ODR produced from the unperturbed electrons passing
through the open spaces of the mesh and OTR from the mirror are observable
above a broad incoherent background from interaction of the heavily scattered
electrons passing through the mesh wires. These interferences (ODTRI) are
sensitive to the beam divergence and can be used to directly diagnose this
parameter. We compare experimental divergence values obtained using ODTRI,
conventional OTRI, for the case when front foil scattering is negligible, and
computed values obtained from transport code calculations and multiple screen
beam size measurements. We obtain good agreement in all cases.


title: Antiblockade in Rydberg excitation of an ultracold lattice gas

abstract:
  It is shown that the two-step excitation scheme typically used to create an
ultracold Rydberg gas can be described with an effective two-level rate
equation, greatly reducing the complexity of the optical Bloch equations. This
allows us to solve the many-body problem of interacting cold atoms with a Monte
Carlo technique. Our results reproduce the Rydberg blockade effect. However, we
demonstrate that an Autler-Townes double peak structure in the two-step
excitation scheme, which occurs for moderate pulse lengths as used in the
experiment, can give rise to an antiblockade effect. It is observable in a
lattice gas with regularly spaced atoms. Since the antiblockade effect is
robust against a large number of lattice defects it should be experimentally
realizable with an optical lattice created by CO$_{2}$ lasers.


title: Self-similar relaxation dynamics of a fluid wedge in a Hele-Shaw cell

abstract:
  Let the interface between two immiscible fluids in a Hele-Shaw cell have, at
t=0, a wedge shape. As a wedge is scale-free, the fluid relaxation dynamics are
self-similar. We find the dynamic exponent of this self-similar flow and show
that the interface shape is given by the solution of an unusual inverse problem
of potential theory. We solve this inverse problem analytically for an almost
flat wedge, and numerically otherwise. The wedge solution is useful for
analysis of pinch-off singularities.


title: The Modern FPGA as Discriminator, TDC and ADC

abstract:
  Recent generations of Field Programmable Gate Arrays (FPGAs) have become
indispensible tools for complex state machine control and signal processing,
and now routinely incorporate CPU cores to allow execution of user software
code. At the same time, their exceptional performance permits low-power
implementation of functionality previously the exclusive domain of dedicated
analog electronics. Specific examples presented here use FPGAs as
discriminator, time-to-digital (TDC) and analog-to-digital converter (ADC). All
three cases are examples of instrumentation for current or future astroparticle
experiments.


title: Supersymmetry and B_s, DO, and Aleph i

abstract:
  Current results from the D0 exp indicate the presence of an oscillation not
explained by the currently accepted theory. An explanation is offered based on
a combination of low-energy 'sring${}^{1/n}$' and 'particle' dynamics. The
dynamics are described by extremely accurate nuclear mass data (unpublished
2006 and \cite{Chalmers1}) in accord with substringy dynamics (in progress,
primary). An event is analyzed with emphasis on particle Iding, their dynamics
and interactions, with implications for/by graviton(ino) with low-energy
phenomenology. Analysis is provided towards enhancing the experimental
apparatus, in computation and hardware, and should be numerically simulated for
further safety before implementation.


title: Asymmetric matrices in an analysis of financial correlations

abstract:
  Financial markets are highly correlated systems that reveal both the
inter-market dependencies and the correlations among their different
components. Standard analyzing techniques include correlation coefficients for
pairs of signals and correlation matrices for rich multivariate data. In the
latter case one constructs a real symmetric matrix with real non-negative
eigenvalues describing the correlation structure of the data. However, if one
performs a correlation-function-like analysis of multivariate data, when a
stress is put on investigation of delayed dependencies among different types of
signals, one can calculate an asymmetric correlation matrix with complex
eigenspectrum. From the Random Matrix Theory point of view this kind of
matrices is closely related to Ginibre Orthogonal Ensemble (GinOE). We present
an example of practical application of such matrices in correlation analyses of
empirical data. By introducing the time lag, we are able to identify temporal
structure of the inter-market correlations. Our results show that the American
and German stock markets evolve almost simultaneously without a significant
time lag so that it is hard to find imprints of information transfer between
these markets. There is only an extremely subtle indication that the German
market advances the American one by a few seconds.


title:
Spanning Trees and bootstrap reliability estimation in correlation based
  networks

abstract:
  We introduce a new technique to associate a spanning tree to the average
linkage cluster analysis. We term this tree as the Average Linkage Minimum
Spanning Tree. We also introduce a technique to associate a value of
reliability to links of correlation based graphs by using bootstrap replicas of
data. Both techniques are applied to the portfolio of the 300 most capitalized
stocks traded at New York Stock Exchange during the time period 2001-2003. We
show that the Average Linkage Minimum Spanning Tree recognizes economic sectors
and sub-sectors as communities in the network slightly better than the Minimum
Spanning Tree does. We also show that the average reliability of links in the
Minimum Spanning Tree is slightly greater than the average reliability of links
in the Average Linkage Minimum Spanning Tree.


title:
Three methods for the description of the temporal response to a SH plane
  impulsive seismic wave in a soft elastic layer overlying a hard elastic
  substratum

abstract:
  We treat the case of a flat stress-free surface (i.e., the ground in
seismological applications) separating air from a homogeneous, isotropic, solid
substratum overlain by a homogeneous, isotropic, solid layer (in contact with
the ground) solicited by a SH plane body wave incident in the substratum. The
analysis is first carried out in the frequency domain and subsequently in the
time domain. The frequency domain response is {\it normal} in that no
resonances are excited (a resonance is here understood to be a situation in
which the response is infinite in the absence of dissipation). The translation
of this in the time domain is that the scattered pulse is of relatively-short
duration. The duration of the pulse is shown to be largely governed by
radiation damping which shows up in the imaginary parts of the complex
eigenfrequencies of the configuration. Three methods are elaborated for the
computation of the time history and give rise to the same numerical solutions
for a large variety of configurations of interest in the geophysical setting
under the hypothesis of non-dissipative, dispersionless media. The method
appealing to the complex eigenfrequency representation is shown to be the
simplest and most physically-explicit way of obtaining the time history (under
the same hypothesis). Moreover, it is particularly suited for the case in which
modes can be excited as occurs when the incident wave is not plane or the
boundary condition is not of the stress-free variety for all transverse
coordinates on the ground plane.


title: An effective method for polarising antiprotons

abstract:
  There exists an inconsistency in the value of the kinetic energies of the
antiproton in the electron laboratory reference frame and of the electron in
the antiproton laboratory reference frame taken wrongly both as 0.65 keV (see
figure 1 and table 2) of the paper. The consequence of this mistake is that the
relative velocity of the electron is not -0.0504 (see table 2) but -0.00118,
i.e. a factor of \sqrt{m_{electron}/m_{proton}} = 1/43 smaller. The consequence
of this factor is that the relative velocity \beta_{relative} in eq. (27) and
\kappa are smaller by this factor. This means that the time for polarisation
build-up is longer by a factor 43. Though the principle idea is not put into
question, the method is not effective "with todays technology" and we have to
withdraw the paper and the proposal.


title: Mean number of visits to sites in Levy flights

abstract:
  Formulas are derived to compute the mean number of times a site has been
visited during symmetric Levy flights. Unrestricted Levy flights are considered
first, for lattices of any dimension: conditions for the existence of finite
asymptotic maps of the visits over the lattice are analysed and a connection is
made with the transience of the flight. In particular it is shown that flights
on lattices of dimension greater than one are always transient. For an interval
with absorbing boundaries the mean number of visits reaches stationary values,
which are computed by means of numerical and analytical methods; comparisons
with Monte Carlo simulations are also presented.


title:
A novel architecture for DAQ in multi-channel, large volume, long drift
  Liquid Argon TPC

abstract:
  Recently a large interest has been shown for multi-ton Liquid Argon
Time-Projection-Chambers (LAr-TPC). The physics issues are very challenging,
but the technical problem of long drifts and adequately long life-time of free
electrons are not solved at all so far. Also one should take into account the
extremely large number of channels required for such large volumes. In this
paper we propose an architecture for DAQ that is based on recent developments
in consumer electronics that made available, at a quite interesting price,
components aimed to high-resolution delta-sigma conversion. This type of ADC is
not at all popular in HEP experiments where normally signals related to events,
well defined in time (triggered), should be converted and recorded. In the
LAr-TPC however we have to deal rather with waveforms that should be converted
and recorded continuously, that is the paramount case of delta-sigma ADC
application.


title:
Simulating the Charge Dispersion Phenomena in Micro Pattern Gas
  Detectors with a Resistive Anode

abstract:
  The TPC for the International Linear Collider (ILC) will need to measure
about 200 track points with a transverse resolution close to 100 microns. The
resolution goal is beyond the capability of the conventional proportional
wire/cathode pad TPC and Micro-Pattern Gas Detectors (MPGD) are being developed
to meet the challenge. The standard MPGD readout techniques will, however, have
difficulty in achieving the ILC-TPC resolution goal with the 2 mm x 6 mm pads
as was initially envisioned. Proposals for smaller width pads will improve the
resolution but will require a larger number of readout channels and increase
the TPC detector cost and complexity. The new MPGD readout concept of charge
dispersion has the potential to achieve the ILC-TPC resolution goal without
resorting to narrower pads. This was recently demonstrated in cosmic ray tests
of a small prototype TPC read out with MPGDs using the charge dispersion
technique. Here we describe the simulation of the charge dispersion phenomena
for the MPGD-TPC. The detailed simulation includes initial ionization
clustering, electron drift, diffusion effects, the intrinsic detector
pulse-shape and electronics effects. The simulation is in excellent agreement
with the experimental data and can be used to optimize the MPGD charge
dispersion readout for the TPC.


title:
Study of the generation intensity in the backward wave oscillator with a
  ''grid'' diffraction grating as a function of the grating length

abstract:
  Experimental studies of the backward wave oscillator with a ''grid''
diffraction grating that is formed by a periodic set of metallic threads inside
a rectangular waveguide are proceeded with study of the generation intensity as
a function of the grating length.


title: Comparison of weighted and unweighted histograms

abstract:
  Two modifications of the chi square test for comparing usual(unweighted) and
weighted histograms and two weighted histograms are proposed. Numerical
examples illustrate an application of the tests for the histograms with
different statistics of events. Proposed tests can be used for the comparison
of experimental data histograms against simulated data histograms and two
simulated data histograms.


title:
A Conjecture for Using Optical Methods for Affecting Superfluid
  Hydrodynamics

abstract:
  The relation between the macroscopic quantum coherent nature of superfluids
and the coherent properties of optical interference patterns will be utilized
to examine the optical properties of superfluid hydrodynamics. A Bragg pattern
imposed on the superfluid (either holographically or using a phase mask) is
expected to induce periodic variations in the local index of refraction of the
normal and super fluid components. The altered optical properties can then be
probed by a second coherent light source. In this manner, the behavior of the
probe beam can be switched using the specific characteristics of the imposed
pattern. Acoustic modes should also manifest measurable affects on incident
coherent radiations.


title:
A new photon recoil experiment: towards a determination of the fine
  structure constant

abstract:
  We report on progress towards a measurement of the fine structure constant to
an accuracy of $5\times 10^{-10}$ or better by measuring the ratio of the
Planck constant to the mass of the cesium atom. Compared to similar
experiments, ours is improved in three significant ways: (i) simultaneous
conjugate interferometers, (ii) multi-photon Bragg diffraction between same
internal states, and (iii) an about 1000 fold reduction of laser phase noise to
-138 dBc/Hz. Combining that with a new method to simultaneously stabilize the
phases of four frequencies, we achieve 0.2 mrad effective phase noise at the
location of the atoms. In addition, we use active stabilization to suppress
systematic effects due to beam misalignment.


title: Quantum Mechanics and Multiply Connected Spaces

abstract:
  t is well known that the difference between Quantum Mechanics and Classical
Theory appears most crucially in the non Classical spin half of the former
theory and the Wilson-Sommerfelt quantization rule. We argue that this is
symptomatic of the fact that Quantum Theory is actually a theory in multiply
connected space while Classical Theory operates in simply connected space.


title:
Luminosity measurement at ATLAS - development, construction and test of
  scintillating fibre prototype detectors

abstract:
  We are reporting about a scintillating fibre tracker which is proposed for
the precise determination of the absolute luminosity of the CERN LHC at
interaction point 1 where the ATLAS experiment is located. The detector needs
to track protons elastically scattered under micro-rad angles in direct
vicinity to the LHC beam. It is based on square shaped scintillating plastic
fibres read out by multi-anode photomultiplier tubes and is housed in Roman
Pots. We describe the design and construction of prototype detectors and the
results of a beam test experiment at DESY. The excellent detector performance
established in this test validates the detector design and supports the
feasibility of the proposed challenging method of luminosity measurement.


title:
Instability and dynamics of two nonlinearly coupled laser beams in a
  plasma

abstract:
  We investigate the nonlinear interaction between two laser beams in a plasma
in the weakly nonlinear and relativistic regime. The evolution of the laser
beams is governed by two nonlinear Schroedinger equations that are coupled with
the slow plasma density response. We study the growth rates of the Raman
forward and backward scattering instabilities as well of the Brillouin and
self-focusing/modulational instabilities. The nonlinear evolution of the
instabilities is investigated by means of direct simulations of the
time-dependent system of nonlinear equations.


title:
Modeling hierarchical structures - Hierarchical Linear Modeling using
  MPlus

abstract:
  The aim of this paper is to present the technique (and its linkage with
physics) of overcoming problems connected to modeling social structures, which
are typically hierarchical. Hierarchical Linear Models provide a conceptual and
statistical mechanism for drawing conclusions regarding the influence of
phenomena at different levels of analysis. In the social sciences it is used to
analyze many problems such as educational, organizational or market dilemma.
This paper introduces the logic of modeling hierarchical linear equations and
estimation based on MPlus software. I present my own model to illustrate the
impact of different factors on school acceptation level.


title:
Bias-Free Estimation in Multicomponent Maximum Likelihood Fits with
  Component-Dependent Templates

abstract:
  The possibility of strong biases in a multicomponent Maximum Likelihood fits
with component-dependent templates has been demonstrated in some toy problems.
We discuss here in detail a problem of practical interest, particle
identification based on time-of-flight or dE/dx information. We show that large
biases can occur in estimating particle fractions in a sample if differences
between the momentum spectra of particles are ignored, and we present a more
robust fit technique, allowing bias-free estimation even when the particle
spectra in the sample are unknown.


title: Bologna and the Cooperation with Developing Countries

abstract:
  A brief recollection is made of the many scientific collaborations of Bologna
with colleagues from Developing Countries. In particular are discussed in
detail the collaborations in some recent Astroparticle Physics experiments.


title:
Edge pinch instability of liquid metal sheet in a transverse
  high-frequency AC magnetic field

abstract:
  We analyze the linear stability of the edge of a thin liquid metal layer
subject to a transverse high-frequency AC magnetic field. The layer is treated
as a perfectly conducting liquid sheet that allows us to solve the problem
analytically for both a semi-infinite geometry with a straight edge and a thin
disk of finite radius. It is shown that the long-wave perturbations of a
straight edge are monotonically unstable when the wave number exceeds some
critical value $k_c,$ which is determined by the surface tension and the linear
density of the electromagnetic force acting on the edge. The higher the density
of electromagnetic force, the shorter the critical wavelength. The
perturbations with wavelength shorter than the critical are stabilized by the
surface tension, whereas the growth rate of long wave perturbations reduces as
$\sim k$ for wave numbers $k\to 0$. Thus, there is the fastest growing
perturbation with the wave number $k_\max=2/3 k_c$. By applying the general
approach developed for the semi-infinite sheet, we find that a circular disk
becomes linearly unstable with respect to exponentially growing perturbation
with the azimuthal wave number $m=2$ when the magnetic Bond number exceeds
$Bm_c=3\pi$. The instability characteristics agree well with the experimental
data.


title: Real estate price peaks: a comparative overview

abstract:
  First, we emphasize that the real estate price peaks which are currently
under way in many industrialized countries (one important exception is Japan)
share many of the characteristics of previous historical price peaks. In
particular, we show that: (i) In the present episode real price increases are,
at least for now, of the same order of magnitude as in previous episodes,
typically of the order of 80 percent to 100 percent. (ii) Historically, price
peaks turned out to be symmetrical with respect to the peak; soft landing, i.e.
an upgoing phase followed by a plateau, has rarely (if ever) been observed.
(iii) The inflated demand is mainly boosted by investors and high-income
buyers. (iv) In the present as well as in previous episodes, the main engines
in the upgoing phase have been the hot markets which developed in major cities
such as London, Los Angeles, New York, Paris, San Francisco or Sydney. In our
conclusion, we propose a prediction for real estate prices in the West of the
United States over the period 2005-2011. We also point out that investment
funds, which already play a key role in stock markets, have in recent times
began to heavily invest in real estate. In the future, one can expect them to
become major players in property markets worldwide. The outcome of the present
episode will tell us how quickly this transformation evolves. Thus, if the
height of the present peak substantially surpasses the magnitude of previous
ones, one may infer that investment funds have been able to establish strong
communication channels between real estate assets on the one hand and financial
assets (e.g. bonds, stocks, options) on the other hand.


title:
Exploring the van der Waals Atom-Surface attraction in the nanometric
  range

abstract:
  The van der Waals atom-surface attraction, scaling as C3 z-3 for z the
atom-surface distance, is expected to be valid in the distance range 1-1000 nm,
covering 8-10 orders of magnitudes in the interaction energy. A Cs vapour
nanocell allows us to analyze the spectroscopic modifications induced by the
atom-surface attraction on the 6P3/2->6D5/2 transition. The measured C3 value
is found to be independent of the thickness in the explored range 40-130 nm,
and is in agreement with an elementary theoretical prediction. We also discuss
the specific interest of exploring short distances and large interaction
energy.


title: White flight or flight from poverty?

abstract:
  The phenomenon of White flight is often illustrated by the case of Detroit
whose population dropped from 1.80 million to 0.95 million between 1950 and
2000 while at the same time its Black and Hispanic component grew from 30
percent to 85 percent. But is this case really representative? The present
paper shows that the phenomenon of White flight is in fact essentially a flight
from poverty. As a confirmation, we show that the changes in White or Black
populations are highly correlated which means that White flight is always
paralleled by Black flight (and Hispanic flight as well). This broader
interpretation of White flight accounts not only for the case of northern
cities such as Cincinnati, Cleveland or Detroit, but for all population changes
at county level, provided the population density is higher than a threshold of
about 50 per square-kilometer which corresponds to moderately urbanized areas
(as can be found in states like Indiana or Virginia for instance).


title:
Greatly enhancing the modeling accuracy for distributed parameter
  systems by nonlinear time/space separation

abstract:
  An effective modeling method for nonlinear distributed parameter systems
(DPSs) is critical for both physical system analysis and industrial
engineering. In this Rapid Communication, we propose a novel DPS modeling
approach, in which a high-order nonlinear Volterra series is used to separate
the time/space variables. With almost no additional computational complexity,
the modeling accuracy is improved more than 20 times in average comparing with
the traditional method.


title:
Quantum mechanical and quasiclassical investigation of the time domain
  nonadiabatic dynamics of NO2 close to the bottom of the X2A1-A2B2 conical
  intersection

abstract:
  We use the effective Hamiltonian that we recently fitted against the first
306 experimentally observed vibronic transitions of NO2 [J. Chem. Phys. 119,
5923 (2003)] to investigate the time domain nonadiabatic dynamics of this
molecule on the coupled X2A1 and A2B2 electronic states, using both quantum
mechanical and quasiclassical techniques. From the quantum mechanical point of
view, we show that the transfer of population to the electronic ground state
originating from a wave packet launched on the excited state occurs in a
stepwise fashion. The evolution of wave packets launched on the electronic
ground state is instead more complex because the crossing seam is located close
to the bottom of the electronic excited state. We next use the mapping
formalism, which replaces the discrete electronic degrees of freedom by
continuous ones, to obtain a classical description of the coupled electronic
states. We propagate gaussian swarms of trajectories to show that this approach
can be used to calculate the populations in each electronic state. We finally
propose a very simple trajectory surface hopping model, which assumes that
trajectories have a constant probability to jump onto the other state in a
particular region of the phase space and a null hopping probability outside
from this region. Quasiclassical calculations show that this model enables a
precise estimation of complex quantities, like for example the projection of
the instantaneous probability density on given planes.


title: Market Mill Dependence Pattern in the Stock Market: Individual Portraits

abstract:
  This paper continues a series of studies of dependence patterns following
from properties of the bivariate probability distribution P(x,y) of two
consecutive price increments x (push) and y (response). The paper focuses on
individual differences of the P(x,y) for 2000 stocks using a methodology of
identification of asymmetric market mill patterns developed in [1,2]. We show
that individual asymmetry patterns (portraits) are remarkably stable over time
and can be classified into three major groups - correlation, anticorrelation
and market mill. We analyze the conditional dynamics resulting from the
properties of P(x,y) for all groups and demonstrate that it is trend-following
at small push magnitudes and contrarian at large ones


title:
Breakdown of Burton-Prim-Slichter approach and lateral solute
  segregation in radially converging flows

abstract:
  A theoretical study is presented of the effect of a radially converging melt
flow, which is directed away from the solidification front, on the radial
solute segregation in simple solidification models. We show that the classical
Burton-Prim-Slichter (BPS) solution describing the effect of a diverging flow
on the solute incorporation into the solidifying material breaks down for the
flows converging along the solidification front. The breakdown is caused by a
divergence of the integral defining the effective boundary layer thickness
which is the basic concept of the BPS theory. Although such a divergence can
formally be avoided by restricting the axial extension of the melt to a layer
of finite height, radially uniform solute distributions are possible only for
weak melt flows with an axial velocity away from the solidification front
comparable to the growth rate. There is a critical melt velocity for each
growth rate at which the solution passes through a singularity and becomes
physically inconsistent for stronger melt flows. To resolve these
inconsistencies we consider a solidification front presented by a disk of
finite radius $R_0$ subject to a strong converging melt flow and obtain an
analytic solution showing that the radial solute concentration depends on the
radius $r$ as $\sim\ln^{1/3}(R_0/r)$ and $\sim\ln(R_0/r)$ close to the rim and
at large distances from it. The logarithmic increase of concentration is
limited in the vicinity of the symmetry axis by the diffusion becoming
effective at a distance comparable to the characteristic thickness of the
solute boundary layer. The converging flow causes a solute pile-up forming a
logarithmic concentration peak at the symmetry axis which might be an
undesirable feature for crystal growth processes.


title:
About the proof of the so called exact classical confidence intervals.
  Where is the trick?

abstract:
  In this note I go through the `proof' of frequentistic confidence intervals
and show what it logically implies concerning the value of a physical quantity
given an experimental observation (nothing).

categories: physics.data-an math.HO math.PR physics.ed-ph


title:
Stable, mode-matched, medium-finesse optical cavity incorporating a
  microcantilever mirror

abstract:
  A stable optical resonator has been built using a 30 micrometer-wide,
metal-coated microcantilever as one mirror. The second mirror was a 12.7
mm-diameter concave dielectric mirror. By positioning the two mirrors 75 mm
apart in a near-hemispherical configuration, a Fabry-Perot cavity with a
finesse equal to 55 was achieved. The finesse was limited by the optical loss
in the cantilever's metal coating; diffraction losses from the small mirror
were negligible. The cavity achieved passive laser cooling of the cantilever's
Brownian motion.


title:
A generalized spatiotemporal covariance model for stationary background
  in analysis of MEG data

abstract:
  Using a noise covariance model based on a single Kronecker product of spatial
and temporal covariance in the spatiotemporal analysis of MEG data was
demonstrated to provide improvement in the results over that of the commonly
used diagonal noise covariance model. In this paper we present a model that is
a generalization of all of the above models. It describes models based on a
single Kronecker product of spatial and temporal covariance as well as more
complicated multi-pair models together with any intermediate form expressed as
a sum of Kronecker products of spatial component matrices of reduced rank and
their corresponding temporal covariance matrices. The model provides a
framework for controlling the tradeoff between the described complexity of the
background and computational demand for the analysis using this model. Ways to
estimate the value of the parameter controlling this tradeoff are also
discussed


title: Energy Scavenging in Silicon Raman Amplifiers

abstract:
  Continuous-wave Raman amplification in silicon waveguides with negative
electrical power dissipation is reported. It is shown that a p-n junction can
simultaneously achieve carrier sweep-out leading to net continuous-wave gain,
and electrical power generation. The approach is also applicable to silicon
Raman lasers and other third-order nonlinear optical devices.


title: Plasmon-Soliton

abstract:
  Formation of a novel hybrid-vector spatial plasmon-soliton in a Kerr slab
embedded in-between metal plates is predicted and analyzed with a modified
NLSE, encompassing hybrid vector field characteristics. Assisted by the
transverse plasmonic effect, the self trapping dimension of the plasmon-soliton
was substantially compressed (compared to the dielectrically cladded slab case)
when reducing the slab width. The practical limitation of the Plasmon-soliton
size reduction is determined by available nonlinear materials and metal loss.
For the extreme reported values of nonlinear index change, we predict soliton
with a cross section of 300nm x 30nm (average dimension of 100nm).


title: Micro-Bioreactor Mimicking a Cellular Environment

abstract:
  We report that a cell-sized water droplet (CWD) with a diameter of several
tens of microns can serve as a micro-biochemical reactor. Since the droplet
inner surface is covered by a phospholipid layer, it provides an environment
similar to that in living cells. The CWD is manipulated with laser tweezers and
we monitor the time-development of biochemical reactions in a single CWD by
fusing two droplets which contain a substrate and an enzyme, respectively. As
actual examples of enzymatic reactions, we present results on the reaction of
calcein with esterase and on the expression reaction of green fluorescent
protein.


title: A Non-Gaussian Approach to Risk Measures

abstract:
  Reliable calculations of financial risk require that the fat-tailed nature of
prices changes is included in risk measures. To this end, a non-Gaussian
approach to financial risk management is presented, modeling the power-law
tails of the returns distribution in terms of a Student-t distribution.
Non-Gaussian closed-form solutions for Value-at-Risk and Expected Shortfall are
obtained and standard formulae known in the literature under the normality
assumption are recovered as a special case. The implications of the approach
for risk management are demonstrated through an empirical analysis of financial
time series from the Italian stock market and in comparison with the results of
the most widely used procedures of quantitative finance. Particular attention
is paid to quantify the size of the errors affecting the market risk measures
obtained according to different methodologies, by employing a bootstrap
technique.


title: Multifractal Model of Asset Returns versus real stock market dynamics

abstract:
  There is more and more empirical evidence that multifractality constitutes
another and perhaps the most significant financial stylized fact. A realistic
model of the financial dynamics should therefore incorporate this effect. The
most promising in this respect is the Multifractal Model of Asset Returns
(MMAR) introduced by Mandelbrot in which multifractality is carried by time
deformation. In our study we focus on the Lux extension to MMAR and empirical
data from Warsaw Stock Exchange. We show that this model is able to reproduce
relevant aspects of the real stock market dynamics.


title:
The effect of multiple internal representations on context rich
  instruction

abstract:
  This paper presents n-coding, a theoretical model of multiple internal mental
representations. The n-coding construct is developed from a review of cognitive
and imaging studies suggesting the independence of information processing along
different modalities: verbal, visual, kinesthetic, social, etc. A study testing
the effectiveness of the n-coding construct in an algebra-based mechanics
course is presented. Four sections differing in the level of n-coding
opportunities were compared. Besides a traditional instruction section used as
a control group, each of the remaining three treatment sections were given
context rich problems following the 'cooperative group problem solving'
approach which differed by the level of n-coding opportunities designed into
their laboratory environment. To measure the effectiveness of the construct,
problem solving skills were assessed as was conceptual learning using the Force
Concept Inventory. However, a number of new measures taking into account
students' confidence in concepts were developed to complete the picture of
student learning. Results suggest that using the developed n-coding construct
to design context rich environments can generate learning gains in problem
solving, conceptual knowledge and concept-confidence.


title: Optimal approximations of power-laws with exponentials

abstract:
  We propose an explicit recursive method to approximate a power-law with a
finite sum of weighted exponentials. Applications to moving averages with long
memory are discussed in relationship with stochastic volatility models.

categories: physics.data-an cond-mat.stat-mech physics.soc-ph q-fin.ST


title:
Chaotic, staggered and polarized dynamics in opinion forming: the
  contrarian effect

abstract:
  We revisit the no tie breaking 2-state Galam contrarian model of opinion
dynamics for update groups of size 3. While the initial model assumes a
constant density of contrarians a for both opinions, it now depends for each
opinion on its global support. Proportionate contrarians are thus found to
indeed preserve the former case main results. However, restricting the
contrarian behavior to only the current collective majority, makes the dynamics
more complex with novel features. For a density a<a_c=1/9 of one-sided
contrarians, a chaotic basin is found in the fifty-fifty region separated from
two majority-minority point attractors, one on each side. For 1/9<a< 0.301 only
the chaotic basin survives. In the range a>0.301 the chaotic basin disappears
and the majority starts to alternate between the two opinions with a staggered
flow towards two point attractors. We then study the effect of both, decoupling
the local update time sequence from the contrarian behavior activation, and a
smoothing of the majority rule. A status quo driven bias for contrarian
activation is also considered. Introduction of unsettled agents driven in the
debate on a contrarian basis is shown to only shrink the chaotic basin. The
model may shed light to recent apparent contradictory elections with on the one
hand very tied results like in US in 2000 and in Germany in 2002 and 2005, and
on the other hand, a huge majority like in France in 2002.


title:
Optical 3D cavity modes below the diffractionlimit using slow-wave
  surface-plasmonpolaritons

abstract:
  Modal volumes at the nano-scale, much smaller than the "diffraction-limit",
with appreciable quality factors, are calculated for a dielectric cavity
embedded in a space between metal plates. The modal field is bounded between
the metal interfaces in one dimension and can be reduced in size almost
indefinitely in this dimension. But more surprisingly, due to the "plasmonic"
slow wave effect, this reduction is accompanied by a similar in-plane modal
size reduction. Another interesting result is that higher order cavity modes
exhibit lower radiation loss. The scheme is studied with effective index
analysis, and validated by FDTD simulations.


title: Five Frequently Fatal Freshman Physics Fantasies

abstract:
  This article describes five common student misconceptions about succeeding in
college-level Physics courses: the miracle finish, the soft hearted professor,
an extension of high school, weak areas won't be tested, and passing is more
important than learning. These fantasies are unique to neither Physics nor
freshman, but the challenge of learning Physics brings more certain negative
consequences to students retaining these attitudes. Ascribing these student
misconceptions to freshmen acknowledges that they diminish with increasing
academic maturity.


title: Generation of surface soliton arrays

abstract:
  We discover that at the edge of optical lattice imprinted in saturable
nonlinear media one-dimensional surface solitons exist only within a band of
light intensities, and that they cease to exist when the lattice depth exceeds
an upper threshold. We also reveal the generation of arrays of two-dimensional
surface solitons mediated by transverse modulational instability of
one-dimensional solitons, a process that is found to exhibit specific features
associated to properties of the optical lattice.


title: Teaching Fourier Analysis and Wave Physics with the Bass Guitar

abstract:
  This article describes a laboratory or demonstration technique employing the
bass guitar and a Vernier LabPro (or a PC soundcard) for teaching wave physics
and introducing Fourier analysis. The Fourier transform of an open string
provides a demonstration of oscillatory modes out to the 20th harmonic
consistent with expectations containing a fundamental frequency and harmonics.
The playing of "harmonics" (suppressing resonant modes by lightly touching the
string to enforce nodes at desired locations) demonstrates oscillations made up
(mostly) of individual modes. Students see that the complete set of Fourier
components (fundamental and harmonics) present on the open string can be
explicitly connected with individual resonant frequencies as described in
typical textbook discussions of natural frequencies of waves on a string. The
use of a bass guitar rather than the six string electric guitar allows higher
harmonics to be individually excited, and it is also easier for students to
play the harmonics themselves.


title:
On the Lagrangian Dynamics of Atmospheric Zonal Jets and the
  Permeability of the Stratospheric Polar Vortex

abstract:
  The Lagrangian dynamics of zonal jets in the atmosphere are considered, with
particular attention paid to explaining why, under commonly encountered
conditions, zonal jets serve as barriers to meridional transport. The velocity
field is assumed to be two-dimensional and incompressible, and composed of a
steady zonal flow with an isolated maximum (a zonal jet) on which two or more
travelling Rossby waves are superimposed. The associated Lagrangian motion is
studied with the aid of KAM (Kolmogorov--Arnold--Moser) theory, including
nontrivial extensions of well-known results. These extensions include
applicability of the theory when the usual statements of nondegeneracy are
violated, and applicability of the theory to multiply periodic systems,
including the absence of Arnold diffusion in such systems. These results,
together with numerical simulations based on a model system, provide an
explanation of the mechanism by which zonal jets serve as barriers to
meridional transport of passive tracers under commonly encountered conditions.
Causes for the breakdown of such a barrier are discussed. It is argued that a
barrier of this type accounts for the sharp boundary of the Antarctic ozone
hole at the perimeter of the stratospheric polar vortex in the austral spring.


title:
All-optical switching, bistability, and slow-light transmission in
  photonic crystal waveguide-resonator structures

abstract:
  We analyze the resonant linear and nonlinear transmission through a photonic
crystal waveguide side-coupled to a Kerr-nonlinear photonic crystal resonator.
Firstly, we extend the standard coupled-mode theory analysis to photonic
crystal structures and obtain explicit analytical expressions for the
bistability thresholds and transmission coefficients which provide the basis
for a detailed understanding of the possibilities associated with these
structures. Next, we discuss limitations of standard coupled-mode theory and
present an alternative analytical approach based on the effective discrete
equations derived using a Green's function method. We find that the discrete
nature of the photonic crystal waveguides allows a novel, geometry-driven
enhancement of nonlinear effects by shifting the resonator location relative to
the waveguide, thus providing an additional control of resonant waveguide
transmission and Fano resonances. We further demonstrate that this enhancement
may result in the lowering of the bistability threshold and switching power of
nonlinear devices by several orders of magnitude. Finally, we show that
employing such enhancements is of paramount importance for the design of
all-optical devices based on slow-light photonic crystal waveguides.


title: Levitated droplet dye laser

abstract:
  We present the first observation, to our knowledge, of lasing from a
levitated, dye droplet. The levitated droplets are created by computer
controlled pico-liter dispensing into one of the nodes of a standing ultrasonic
wave (100 kHz), where the droplet is trapped. The free hanging droplet forms a
high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine
6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are
optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser,
and the dye laser emission is analyzed by a fixed grating spectrometer. With
this setup we have achieved reproducible lasing spectra in the visible
wavelength range from 610 nm to 650 nm. The levitated droplet technique has
previously successfully been applied for a variety of bio-analytical
applications at single cell level. In combination with the lasing droplets, the
capability of this high precision setup has potential applications within
highly sensitive intra-cavity absorbance detection.


title: BEPCII/BESIII Upgrade and the Prospective Physics

abstract:
  The Status of BEPCII/BESIII upgrade is described, BEPCII is designed to reach
a luminosity of $10^{33}/cm^{-2}s^{-1}$ at c. m. energy of 3.89GeV, and BESIII
detector is fully rebuilt. The project is on track and is progressing well. The
machine and detector are expected to commission together at the late half of
2007, and start to take some engineer run end of 2007 or beginning of 2008.


title: Collisional shifts in optical-lattice atom clocks

abstract:
  We theoretically study the effects of elastic collisions on the determination
of frequency standards via Ramsey fringe spectroscopy in optical-lattice atom
clocks. Interparticle interactions of bosonic atoms in multiply-occupied
lattice sites can cause a linear frequency shift, as well as generate
asymmetric Ramsey fringe patterns and reduce fringe visibility due to
interparticle entanglement. We propose a method of reducing these collisional
effects in an optical lattice by introducing a phase difference of $\pi$
between the Ramsey driving fields in adjacent sites. This configuration
suppresses site to site hopping due to interference of two tunneling pathways,
without degrading fringe visibility. Consequently, the probability of double
occupancy is reduced, leading to cancellation of collisional shifts.


title: Unexpected Magnetism of Small Silver Clusters

abstract:
  The ground-state electronic, structural, and magnetic properties of small
silver clusters, Ag$_n$ (2$\le$n$\le$22), have been studied using a linear
combination of atomic Gaussian-type orbitals within the density functional
theory. The results show that the silver atoms, which are diamagnetic in bulk
environment, can be magnetic when they are grouped together in clusters. The
Ag$_{13}$ cluster with icosahedral symmetry has the highest magnetic moment per
atom among the studied silver clusters. The cluster symmetry and the reduced
coordination number specific of small clusters reveal as a fundamental factor
for the onset of the magnetism.