title: Networks based on collisions among mobile agents

abstract:
  We investigate in detail a recent model of colliding mobile agents [Phys.
Rev. Lett.~96, 088702], used as an alternative approach to construct evolving
networks of interactions formed by the collisions governed by suitable
dynamical rules. The system of mobile agents evolves towards a quasi-stationary
state which is, apart small fluctuations, well characterized by the density of
the system and the residence time of the agents. The residence time defines a
collision rate and by varying the collision rate, the system percolates at a
critical value, with the emergence of a giant cluster whose critical exponents
are the ones of two-dimensional percolation. Further, the degree and clustering
coefficient distributions and the average path length show that the network
associated with such a system presents non-trivial features which, depending on
the collision rule, enables one not only to recover the main properties of
standard networks, such as exponential, random and scale-free networks, but
also to obtain other topological structures. Namely, we show a specific example
where the obtained structure has topological features which characterize
accurately the structure and evolution of social networks in different
contexts, ranging from networks of acquaintances to networks of sexual
contacts.


title:
Correcting ray optics at curved dielectric microresonator interfaces:
  Phase-space unification of Fresnel filtering and the Goos-Haenchen shift

abstract:
  We develop an amended ray optics description for reflection at the curved
dielectric interfaces of optical microresonators which improves the agreement
with wave optics by about one order of magnitude. The corrections are separated
into two contributions of similar magnitude, corresponding to ray displacement
in independent quantum phase space directions, which can be identified with
Fresnel filtering and the Goos-Haenchen shift, respectively. Hence we unify two
effects which only have been studied separately in the past.


title:
Axially symmetric focusing as a cuspoid diffraction catastrophe: Scalar
  and vector cases and comparison with the theory of Mie

abstract:
  An analytical description of arbitrary strongly aberrated axially symmetric
focusing is developed. This is done by matching the solution of geometrical
optics with a wave pattern which is universal for the underlying ray structure.
The corresponding canonical integral is the Bessoid integral, which is a three
dimensional generalization of the Pearcey integral that approximates the field
near an arbitrary two-dimensional cusp. We first develop the description for
scalar fields and then generalize it to the vector case. As a practical example
the formalism is applied to the focusing of light by transparent dielectric
spheres with a few wavelengths in diameter. The results demonstrate good
agreement with the Mie theory down to Mie parameters of about 30. Compact
analytical expressions are derived for the intensity on the axis and the
position of the diffraction focus both for the general case and for the
focusing by microspheres. The high intensity region is narrower than for an
ideal lens of the same aperture at the expense of longitudinal localization and
has a polarization dependent fine structure, which can be explained
quantitatively. The results are relevant for aerosol and colloid science where
natural light focusing occurs and can be used in laser micro- and
nano-processing of materials.


title:
Zero-dispersion Wavelength Mapping in Short Single-Mode Optical Fibers
  Using Parametric Amplification

abstract:
  We demonstrate a novel convenient nondestructive method based on optical
parametric amplification that allows retrieval of the zero-dispersion
wavelength map along a short optical fiber span with a high-spatial resolution.
The improved resolution relies on the high sensitivity to the local
longitudinal dispersion fluctuations of the parametric high-gain spectrum.


title:
Controlling electronic spin relaxation of cold molecules with electric
  fields

abstract:
  We present a theoretical study of atom - molecule collisions in superimposed
electric and magnetic fields and show that dynamics of electronic spin
relaxation in molecules at temperatures below 0.5 K can be manipulated by
varying the strength and the relative orientation of the applied fields. The
mechanism of electric field control of Zeeman transitions is based on an
intricate interplay between intramolecular spin-rotation couplings and
molecule-field interactions. We suggest that electric fields may affect
chemical reactions through inducing nonadiabatic spin transitions and
facilitate evaporative cooling of molecules in a magnetic trap.


title:
Reducing Polarization Mode Dispersion With Controlled Polarization
  Rotations

abstract:
  One of the fundamental limitations to high bit rate, long distance,
telecommunication in optical fibers is Polarization Mode Dispersion (PMD). Here
we introduce a conceptually new method to reduce PMD in optical fibers by
carrying out controlled rotations of polarization at predetermined locations
along the fiber. The distance between these controlled polarization rotations
must be less than both the beat length and the mode coupling length of the
fiber. This method can also be combined with the method in which the fiber is
spun while it drawn. The incidence of imperfections on the efficiency of the
method is analysed.


title:
Research of Open Systems Evolution by the Method of Multifractal
  Analysis

abstract:
  Processes occurring in real open systems are far from equilibrium state and
they can lead to synergetic effects, which are caused by coordinated behavior
of system units. Traditional methods of analysis often just establish such
behavior, but they are not able to reveal the mechanism of the process in full
measure and to explain observed structural modifications from the standard
positions. A qualitatively new approach to the research of nonlinear effects in
complex systems is considered in the paper. From the positions of synergetics,
a structural state, which appears in the system due to nonlinear processes, can
be considered as a multifractal. Synergetic parameters of the structure
calculated at the multifractal analysis give additional information about
occurring modifications and promote discovering of process mechanism.


title:
An economical method to calculate eigenvalues of the Schroedinger
  Equation

abstract:
  The method is an extension to negative energies of a spectral integral
equation method to solve the Schroedinger equation, developed previously for
scattering applications. One important innovation is a re-scaling procedure in
order to compensate for the exponential behaviour of the negative energy
Green's function. Another is the need to find approximate energy eigenvalues,
to serve as starting values for a subsequent iteration procedure. In order to
illustrate the new method, the binding energy of the He-He dimer is calculated,
using the He-He TTY potential. In view of the small value of the binding
energy, the wave function has to be calculated out to a distance of 3000 a.u.
Two hundred mesh points were sufficient to obtain an accuracy of three
significant figures for the binding energy, and with 320 mesh points the
accuracy increased to six significant figures. An application to a potential
with two wells separated by a barrier, is also made.


title:
Narrowband and ultranarrowband filters with electro-optic structurally
  chiral materials

abstract:
  When a circularly polarized plane wave is normally incident on a slab of a
structurally chiral material with local $\bar{4}2m$ point group symmetry and a
central twist defect, the slab can function as either a narrowband reflection
hole filter for co-handed plane waves or an ultranarrowband transmission hole
filter for cross-handed plane waves, depending on its thickness and the
magnitude of the applied dc electric field. Exploitation of the Pockels effect
significantly reduces the thickness of the slab.


title:
Structure, electronic properties and magnetic transition in manganese
  clusters

abstract:
  We systematically investigate the structural, electronic and magnetic
properties of Mn$_n$ clusters ($n =$ 2$-$20) within the {\it ab-initio}
pseudopotential plane wave method using generalized gradient approximation for
the exchange-correlation energy. A new kind of icosahedral structural growth
has been predicted in the intermediate size range. Calculated magnetic moments
show an excellent agreement with the Stern-Gerlach experiment. A transition
from ferromagnetic to ferrimagnetic Mn$-$Mn coupling takes place at $n=$ 5 and
the ferrimagnetic states continue to be the ground states for the entire size
range. Possible presence of multiple isomers in the experimental beam has been
argued. No signature of non-metal to metal transition is observed in this size
range and the coordination dependence of $d-$electron localization is
discussed.


title:
Collisionless energy absorption in nanoplasma layer in regular and
  stochastic regimes

abstract:
  Collisionless energy absorption in 1D nanoplasma layer is considered.
Straightforward classical calculation of the absorption rate in action-angle
variables is presented. In regular regime the result obtained is the same as in
[Zaretsky et.al., 2004], but deeper insight is possible now due to the
technique used. Chirikov criterion of the chaotic absorption regime is written
out. Collisionless energy absorption rate in nanoplasma layer is calculated in
stochastic regime.


title: Parameters for a Super-Flavor-Factory

abstract:
  A Super Flavor Factory, an asymmetric energy e+e- collider with a luminosity
of order 10^36 cm-2s-1, can provide a sensitive probe of new physics in the
flavor sector of the Standard Model. The success of the PEP-II and KEKB
asymmetric colliders in producing unprecedented luminosity above 10^34 cm-2s-1
has taught us about the accelerator physics of asymmetric e+e- colliders in a
new parameter regime. Furthermore, the success of the SLAC Linear Collider and
the subsequent work on the International Linear Collider allow a new
Super-Flavor collider to also incorporate linear collider techniques. This note
describes the parameters of an asymmetric Flavor-Factory collider at a
luminosity of order 10^36 cm-2s-1 at the Upsilon(4S) resonance and about 10^35
cm-2s-1 at the Tau production threshold. Such a collider would produce an
integrated luminosity of about 10,000 fb-1 (10 ab-1) in a running year (10^7
sec) at the Upsilon(4S) resonance.


title: Linear vs. Nonlinear Diffusion and Martingale Option Pricing

abstract:
  First, classes of Markov processes that scale exactly with a Hurst exponent H
are derived in closed form. A special case of one class is the Tsallis density,
advertised elsewhere as nonlinear diffusion or diffusion with nonlinear
feedback. But the Tsallis model is only one of a very large class of linear
diffusion with a student-t like density. Second, we show by stochastic calculus
that our generalization of the Black-Scholes partial differential equation
(pde) for variable diffusion coefficients is equivalent to a Martingale in the
risk neutral discounted stock price. Previously, this was proven for the
restricted case of Gaussian logarithmic returns by Harrison and Kreps, but we
prove it here for large classes of empirically useful and theoretically
interesting returns models where the diffusion coefficient D(x,t) depends on
both logarithmic returns x and time t. Finally, we prove that option prices
blow up if fat tails in returns x are included in the market distribution.


title:
Coordinate System And Coordinate Transformations Based On Wave Nature Of
  Light

abstract:
  The Classical Coordinate System is geometrical by nature with time being an
external variable. Constructing a classical coordinate system employs a
point-like signal with infinite speed. In Special Relativity Theory the speed
is limited but the signal is a point-like particle (photon). If the oscillatory
nature of light is considered, an event in absolute space is to be
characterized by three coordinates namely, distance, time and phase. The
Galilean transformation equations for space and time coordinates should be
complemented by a third equation that accounts for the phase transformation.
Wave equation remains invariant under such transformation and kinematical
equivalence of inertial reference frames is conserved. Lorentz transforms apply
to wave length and wave period of the exchanged light signal in a dynamic
set-up.


title:
Scintillator counters with multi-pixel avalanche photodiode readout for
  the ND280 detector of the T2K experiment

abstract:
  The Tokai-to-Kamioka (T2K) experiment is a second generation long baseline
neutrino oscillation experiment which aims at a sensitive search for the nu_e
appearance. The main design features of the T2K near detectors located at 280 m
from the target are presented. Scintillator counters developed for the T2K near
detectors are described. Readout of the counters is provided via WLS fibers
embedded into S-shape grooves in a scintillator and viewed from both ends by
multi-pixel avalanche photodiodes operating in a limited Geiger mode. A
desription, operational principles and the results of tests of photosensors
with a sensitive area of 1.1 mm^2 are presented. A time resolution of 1.5 ns, a
spatial resolution of 9.9-12.4 cm, and a MIP detection efficiency of more than
99% were obtained for scintillator detectors in a beam test.


title: Crossover between Levy and Gaussian regimes in first passage processes

abstract:
  We propose a new approach to the problem of the first passage time. Our
method is applicable not only to the Wiener process but also to the
non--Gaussian L$\acute{\rm e}$vy flights or to more complicated stochastic
processes whose distributions are stable. To show the usefulness of the method,
we particularly focus on the first passage time problems in the truncated
L$\acute{\rm e}$vy flights (the so-called KoBoL processes), in which the
arbitrarily large tail of the L$\acute{\rm e}$vy distribution is cut off. We
find that the asymptotic scaling law of the first passage time $t$ distribution
changes from $t^{-(\alpha +1)/\alpha}$-law (non-Gaussian L$\acute{\rm e}$vy
regime) to $t^{-3/2}$-law (Gaussian regime) at the crossover point. This result
means that an ultra-slow convergence from the non-Gaussian L$\acute{\rm e}$vy
regime to the Gaussian regime is observed not only in the distribution of the
real time step for the truncated L$\acute{\rm e}$vy flight but also in the
first passage time distribution of the flight. The nature of the crossover in
the scaling laws and the scaling relation on the crossover point with respect
to the effective cut-off length of the L$\acute{\rm e}$vy distribution are
discussed.


title: Data production models for the CDF experiment

abstract:
  The data production for the CDF experiment is conducted on a large Linux PC
farm designed to meet the needs of data collection at a maximum rate of 40
MByte/sec. We present two data production models that exploits advances in
computing and communication technology. The first production farm is a
centralized system that has achieved a stable data processing rate of
approximately 2 TByte per day. The recently upgraded farm is migrated to the
SAM (Sequential Access to data via Metadata) data handling system. The software
and hardware of the CDF production farms has been successful in providing large
computing and data throughput capacity to the experiment.


title: Queueing theoretical analysis of foreign currency exchange rates

abstract:
  We propose a useful approach for investigating the statistical properties of
foreign currency exchange rates. Our approach is based on queueing theory,
particularly, the so-called renewal-reward theorem. For the first passage
processes of the Sony Bank US dollar/Japanese yen (USD/JPY) exchange rate, we
evaluate the average waiting time which is defined as the average time that
customers have to wait between any instant when they want to observe the rate
(e.g. when they log in to their computer systems) and the next rate change. We
find that the assumption of exponential distribution for the first-passage
process should be rejected and that a Weibull distribution seems more suitable
for explaining the stochastic process of the Sony Bank rate. Our approach also
enables us to evaluate the expected reward for customers, i.e. one can predict
how long customers must wait and how much reward they will obtain by the next
price change after they log in to their computer systems. We check the validity
of our prediction by comparing it with empirical data analysis.


title: Correlation matrix decomposition of WIG20 intraday fluctuations

abstract:
  Using the correlation matrix formalism we study the temporal aspects of the
Warsaw Stock Market evolution as represented by the WIG20 index. The high
frequency (1 min) WIG20 recordings over the time period between January 2001
and October 2005 are used. The entries of the correlation matrix considered
here connect different distinct periods of the stock market dynamics, like days
or weeks. Such a methodology allows to decompose the price fluctuations into
the orthogonal eigensignals that quantify different modes of the underlying
dynamics. The magnitudes of the corresponding eigenvalues reflect the strengths
of such modes. One observation made in this paper is that strength of the daily
trend in the WIG20 dynamics systematically decreases when going from 2001 to
2005. Another is that large events in the return fluctuations are primarily
associated with a few most collective eigensignals.

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


title: Data processing model for the CDF experiment

abstract:
  The data processing model for the CDF experiment is described. Data
processing reconstructs events from parallel data streams taken with different
combinations of physics event triggers and further splits the events into
datasets of specialized physics datasets. The design of the processing control
system faces strict requirements on bookkeeping records, which trace the status
of data files and event contents during processing and storage. The computing
architecture was updated to meet the mass data flow of the Run II data
collection, recently upgraded to a maximum rate of 40 MByte/sec. The data
processing facility consists of a large cluster of Linux computers with data
movement managed by the CDF data handling system to a multi-petaByte Enstore
tape library. The latest processing cycle has achieved a stable speed of 35
MByte/sec (3 TByte/day). It can be readily scaled by increasing CPU and
data-handling capacity as required.


title: The Web Graph of a Tourism System

abstract:
  The website network of a tourism destination is examined. Network theoretic
metrics are used to gauge the static and dynamic characteristics of the
webspace. The topology of the network is found partly similar to the one
exhibited by similar systems. However, some differences are found, mainly due
to the relatively poor connectivity and clusterisation of the network.
  These results are interpreted by considering the formation mechanisms and the
connotation of the linkages between websites. Clustering and assortativity
coefficients are proposed as quantitative estimations of the degree of
collaboration and cooperation among destination stakeholders.


title: Notes on the Dipole Coordinate System

abstract:
  A strong magnetic field can make it advantageous to work in a coordinate
system aligned with dipolar field lines. This monograph collect the formulas
for some of the most frequently used expressions and operations in dipole
coordinates.


title: Brewster's angle for anisotropic material from the extinction theorem

abstract:
  By the extinction theorem we explore the Brewster effect in the external and
internal reflections of electromagnetic wave associated with an anisotropic
material that is both dielectric and magnetic, including metamaterials. We
obtain Fresnel's coefficients and the condition of Brewster's angle, and give
microscopic explanations from the view point of molecular optics. The Brewster
angle is the incidence of angle at which the contribution of all electric and
magnetic dipoles in the anisotropic material to the reflection field becomes
zero. Distinct from isotropic media, the anisotropic material can exhibit
Brewster angle for both TE and TM waves due to the anisotropy of the material.


title: Still the "World's Fastest Derivation of the Lorentz Transformation"

abstract:
  Rothenstein's claim of a ``faster'' derivation of the Lorentz transformation
is not correct.


title:
Collisionless magnetic field reconnection from first principles: What it
  can and cannot do

abstract:
  The underlying concepts of collisionless magnetic field reconnection in the
vicinity of the diffusion regions are developed qualitatively from first
principles. One conclusion of this analysis is that energetic ions and
electrons observed in the terrestrial magnetosphere or from the sun are not
accelerated to the observed energies in the diffusion regions.


title:
High-accuracy calculation of black-body radiation shift in $^{133}$Cs
  primary frequency standard

abstract:
  Black-body radiation (BBR) shift is an important systematic correction for
the atomic frequency standards realizing the SI unit of time. Presently, there
is a controversy over the value of the BBR shift for the primary $^{133}$Cs
standard. At room temperatures the values from various groups differ at $3
\times 10^{-15}$ level, while the modern clocks are aiming at $10^{-16}$
accuracies. We carry out high-precision relativistic many-body calculations of
the BBR shift. For the BBR coefficient $\beta$ at $T=300K$ we obtain
$\beta=-(1.708\pm0.006) \times 10^{-14}$, implying $6 \times 10^{-17}$
fractional uncertainty. While in accord with the most accurate measurement, our
0.35%-accurate value is in a substantial, 10%, disagreement with recent
semi-empirical calculations. We identify an oversight in those calculations.


title: Indirect methods for wake potential integration

abstract:
  The development of the modern accelerator and free-electron laser projects
requires to consider wake fields of very short bunches in arbitrary three
dimensional structures. To obtain the wake numerically by direct integration is
difficult, since it takes a long time for the scattered fields to catch up to
the bunch. On the other hand no general algorithm for indirect wake field
integration is available in the literature so far. In this paper we review the
known indirect methods to compute wake potentials in rotationally symmetric and
cavity-like three dimensional structures. For arbitrary three dimensional
geometries we introduce several new techniques and test them numerically.


title:
Influence of gravitational field on quantum-nondemolition measurement of
  atomic momentum in the dispersive Jaynes-Cummings model

abstract:
  We present a theoretical scheme based on su(2) algebra to investigate the
influence of homogeneous gravitational field on the quantum nondemolition
measurement of atomic momentum in dispersive Jaynes-Cummings model. In the
dispersive Jaynes-Cummings model, when detuning is large and the atomic motion
is in a propagating light wave, we consider a two-level atom with quantized
cavity-field in the presence of a homogeneous gravitational field. We derive an
effective Hamiltonian describing the dispersive atom-field interaction in the
presence of gravitational field. We can see gravitational influence both on the
momentum filter and momentum distribution. Moreover, gravitational field
decreases both tooth spacing of momentum and the width of teeth of momentum.


title: ACORDE a Cosmic Ray Detector for ALICE

abstract:
  ACORDE is one of the ALICE detectors, presently under construction at CERN.
It consists of an array of plastic scintillator counters placed on the three
upper faces of the ALICE magnet. It will act as a cosmic ray trigger, and,
together with other ALICE sub-detectors, will provide precise information on
cosmic rays with primary energies around $10^{15} \div 10^{-17}$ eV. Here we
describe the design review of ACORDE along with the present status and
integration into ALICE.


title: Enhanced transmission of slit arrays in an extremely thin metallic film

abstract:
  Horizontal resonances of slit arrays are studied. They can lead to an
enhanced transmission that cannot be explained using the single-mode
approximation. A new type of cavity resonance is found when the slits are
narrow for a wavelength very close to the period. It can be excited for very
low thicknesses. Optimization shows these structures could constitute
interesting monochromatic filters.


title:
Optimal estimation for Large-Eddy Simulation of turbulence and
  application to the analysis of subgrid models

abstract:
  The tools of optimal estimation are applied to the study of subgrid models
for Large-Eddy Simulation of turbulence. The concept of optimal estimator is
introduced and its properties are analyzed in the context of applications to a
priori tests of subgrid models. Attention is focused on the Cook and Riley
model in the case of a scalar field in isotropic turbulence. Using DNS data,
the relevance of the beta assumption is estimated by computing (i) generalized
optimal estimators and (ii) the error brought by this assumption alone. Optimal
estimators are computed for the subgrid variance using various sets of
variables and various techniques (histograms and neural networks). It is shown
that optimal estimators allow a thorough exploration of models. Neural networks
are proved to be relevant and very efficient in this framework, and further
usages are suggested.


title: START: low-noise efficient trigger for cosmic muons

abstract:
  Noise characteristics and MIP registration efficiency of the Scintillation
Tile with MRS APD Light Readout (START) were measured with cosmic particles.
Encouraging results open a broad range of possibilities for using START in
large-scale applications, requiring low-noise, efficient and stable trigger for
cosmic muons.


title:
Non-classical Energy Conservation in Multi-wave Systems: "Extra Energy",
  "Negative Energy" and "Annihilation of Energy"

abstract:
  The energy conservation is a general law of nature. In the classical physics,
the energy W_{AB} of a conservative system {AB} that contains the objects A and
B is equal to a sum of the positive energies W_A and W_B of the isolated
objects A and B, W_{AB} = W_A+W_B. We show that the energy conservation does
not exhibit the "classic law" if the physical objects are waves or they do have
a wave nature of microscopic (quantum) objects. The "extra energy", "negative
energy" and "annihilation of energy" are predicted for multi-wave (multi-beam)
systems. The paradoxical phenomenon is demonstrated in context of the
extraordinary transmission of light and matter through subwavelength aperture
arrays assisted by surface waves [T.W. Ebbesen et al., Nature (London) 391,
667(1998)) and E. Moreno et al., Phys. Rev. Lett. 95, 170406 (2005)].


title: Non-Classical Expected Utility Theory

abstract:
  In this paper we extend Savage's theory of decision-making under uncertainty
from a classical environment into a non-classical one. We formulate the
corresponding axioms and provide representation theorems for qualitative
measures and expected utility.


title: Aging in Financial Market

abstract:
  We analyze the data of the Italian and U.S. futures on the stock markets and
we test the validity of the Continuous Time Random Walk assumption for the
survival probability of the returns time series via a renewal aging experiment.
We also study the survival probability of returns sign and apply a coarse
graining procedure to reveal the renewal aspects of the process underlying its
dynamics.


title: Electron transfer theory revisit: Quantum solvation effect

abstract:
  The effect of solvation on the electron transfer (ET) rate processes is
investigated on the basis of the exact theory constructed in J. Phys. Chem. B
Vol. 110, (2006); quant-ph/0604071. The nature of solvation is studied in a
close relation with the mechanism of ET processes. The resulting Kramers'
turnover and Marcus' inversion characteristics are analyzed accordingly. The
classical picture of solvation is found to be invalid when the solvent
longitudinal relaxation time is short compared with the inverse temperature.


title: BEPCII and BESIII

abstract:
  The Beijing Electron Collider is being upgraded (BEPCII) to a two-ring
collider with a design luminosity of $1 \times 10^{33}$cm$^{-2}$ s$^{-1}$ at a
center-of-mass energy of 3.89 GeV. It will operate between 2 and 4.2 GeV in the
center of mass. With this luminosity, the BESIII detector will be able to
collect, for example, 10 billion $J/\psi$ events in one year of running. This
will be a unique facility in the world opening many physics opportunities.
BEPCII and BESIII are currently under construction, and commissioning of both
is expected to begin in summer 2007.


title: Self-organizing social hierarchy and villages in a challenging society

abstract:
  We show by Monte Calro (MC) simulation that the hierarchy and villages emerge
simultaneously in a challenging society when the population density exceeds a
critical value. Our results indicate that among controlling processes of
diffusion and fighting of individuals and relaxation of wealth, the trend of
individuals challeninging to stronger neighbors plays the pivotal role in the
self-organization of the hierarchy and villages.


title:
On the production of flat electron bunches for laser wake field
  acceleration

abstract:
  We suggest a novel method for injection of electrons into the acceleration
phase of particle accelerators, producing low emittance beams appropriate even
for the demanding high energy Linear Collider specifications. In this paper we
work out the injection into the acceleration phase of the wake field in a
plasma behind a high intensity laser pulse, taking advantage of the laser
polarization and focusing. With the aid of catastrophe theory we categorize the
injection dynamics. The scheme uses the structurally stable regime of
transverse wake wave breaking, when electron trajectory self-intersection leads
to the formation of a flat electron bunch. As shown in three-dimensional
particle-in-cell simulations of the interaction of a laser pulse in a
line-focus with an underdense plasma, the electrons, injected via the
transverse wake wave breaking and accelerated by the wake wave, perform
betatron oscillations with different amplitudes and frequencies along the two
transverse coordinates. The polarization and focusing geometry lead to a way to
produce relativistic electron bunches with asymmetric emittance (flat beam). An
approach for generating flat laser accelerated ion beams is briefly discussed.


title:
Modeling Society with Statistical Mechanics: an Application to Cultural
  Contact and Immigration

abstract:
  We introduce a general modeling framework to predict the outcomes, at the
population level, of individual psychology and behavior. The framework
prescribes that researchers build a cost function that embodies knowledge of
what trait values (opinions, behaviors, etc.) are favored by individual
interactions under given social conditions. Predictions at the population level
are then drawn using methods from statistical mechanics, a branch of
theoretical physics born to link the microscopic and macroscopic behavior of
physical systems. We demonstrate our approach building a model of cultural
contact between two cultures (e.g., immigration), showing that it is possible
to make predictions about how contact changes the two cultures.

categories: physics.soc-ph cond-mat.stat-mech math-ph math.MP


title:
Amphoteric refraction at the interface between isotropic and anisotropic
  media

abstract:
  It is found that the amphoteric refraction, i.e. the refraction can be either
positive or negative depending on the incident angles, could occur at a planar
interface associated with a uniaxially anisotropic positive index media (PIM)
or an anisotropic negative index media (NIM). Particularly, the anomalous
negative refraction can occur at a planar interface from an isotropic PIM to an
anisotropic PIM, whereas the anomalous positive refraction occurs at the
interface from an isotropic PIM to an anisotropic NIM. The optimal conditions
to yield the two unusual refractions are obtained. The difference of the two
types of amphoteric refraction is discussed.


title: A Roof over your Head; House Price Peaks in the UK and Ireland

abstract:
  We analyse, following recent work of Roehner, changes in house prices for
both the UK and Ireland. We conclude that prices in London have reached a
tipping point and prices relative to inflation are set to fall over the next
few years. If inflation does not rise then a hard landing seems likely. House
prices in the Irish Republic are shown to have broken away from the moderate
rise still to be found in Northern Ireland and Dublin has emerged as another
global 'hot spot'. An evolution of Dublin house prices similar to that in
London can be anticipated. Keywords: Econophysics, house prices, real estate,
prediction PACS: 89.65.Gh, 89.90.+n


title:
Optical transfer cavity stabilization using current-modulated
  injection-locked diode lasers

abstract:
  It is demonstrated that RF current modulation of a frequency stabilized
injection-locked diode laser allows the stabilization of an optical cavity to
adjustable lengths, by variation of the RF frequency. This transfer cavity may
be used to stabilize another laser at an arbitrary wavelength, in the absence
of atomic or molecular transitions suitable for stabilization. Implementation
involves equipment and techniques commonly used in laser cooling and trapping
laboratories, and does not require electro- or acousto-optic modulators. With
this technique we stabilize a transfer cavity using a RF current-modulated
diode laser which is injection locked to a 780 nm reference diode laser. The
reference laser is stabilized using polarization spectroscopy in a Rb cell. A
Ti:sapphire ring laser at 960 nm is locked to this transfer cavity and may be
precisely scanned by varying the RF modulation frequency. We demonstrate the
suitability of this system for the excitation of laser cooled Rb atoms to
Rydberg states.


title:
Quantification of optical pulsed-plane-wave-shaping by chiral sculptured
  thin films

abstract:
  The durations and average speeds of ultrashort optical pulses transmitted
through chiral sculptured thin films (STFs) were calculated using a
finite-difference time-domain algorithm. Chiral STFs are a class of
nanoengineered materials whose microstructure comprises parallel helicoidal
nanowires grown normal to a substrate. The nanowires are $\sim$10-300 nm in
diameter and $\sim1-10 \mu$m in length. Durations of transmitted pulses tend to
increase with decreasing (free-space) wavelength of the carrier plane wave,
while average speeds tend to increase with increasing wavelength. An increase
in nonlinearity, as manifested by an intensity-dependent refractive index in
the frequency domain, tends to increase durations of transmitted pulses and
decrease average speeds. The circular Bragg phenomenon exhibited by a chiral
STFs manifests itself in the frequency domain as high reflectivity for normally
incident carrier plane waves whose circular polarization state is matched to
the structural handedness of the film and whose wavelength falls in a range
known as the Bragg regime; films of the opposite structural handedness reflect
such plane waves little. This effect tends to distort the shapes of transmitted
pulses with respect to the incident pulses, and such shaping can cause sharp
changes in some measures of average speed with respect to carrier wavelength. A
local maximum in the variation of one measure of the pulse duration with
respect to wavelength is noted and attributed to the circular Bragg phenomenon.
Several of these effects are explained via frequency-domain arguments. The
presented results serve as a foundation for future theoretical and experimental
studies of optical pulse propagation through causal, nonlinear, nonhomogeneous,
and anisotropic materials.


title:
Low-Light-Level Optical Interactions with Rubidium Vapor in a Photonic
  Bandgap Fiber

abstract:
  We show that a Rubidium vapor can be produced within the core of a photonic
band-gap fiber yielding an optical depth in excess of 2000. Our technique for
producing the vapor is based on coating the inner walls of the fiber core with
an organosilane and using light-induced atomic desorption to release Rb atoms
into the core. We develop a model to describe the dynamics of the atomic
density, and as an initial demonstration of the potential of this system for
supporting ultra-low-level nonlinear optical interactions, we perform
electromagnetically-induced transparency with control-field powers in the
nanowatt regime, which represents more than a 1000-fold reduction from the
power required for bulk, focused geometries.


title: Power-law behavior and condensation phenomena in disordered urn models

abstract:
  We investigate equilibrium statistical properties of urn models with
disorder. Two urn models are proposed; one belongs to the Ehrenfest class, and
the other corresponds to the Monkey class. These models are introduced from the
view point of the power-law behavior and randomness; it is clarified that
quenched random parameters play an important role in generating power-law
behavior. We evaluate the occupation probability $P(k)$ with which an urn has
$k$ balls by using the concept of statistical physics of disordered systems. In
the disordered urn model belonging to the Monkey class, we find that above
critical density $\rho_\mathrm{c}$ for a given temperature, condensation
phenomenon occurs and the occupation probability changes its scaling behavior
from an exponential-law to a heavy tailed power-law in large $k$ regime. We
also discuss an interpretation of our results for explaining of macro-economy,
in particular, emergence of wealth differentials.


title:
Zero permeability and zero permittivity band gaps in 1D metamaterial
  photonic crystals

abstract:
  We consider layered heterostructures combining ordinary positive index
materials and dispersive metamaterials. We show that these structures can
exhibit a new type of photonic gap around frequencies where either the magnetic
permeability \mu or the electric permittivity \epsilon of the metamaterial is
zero. Although the interface of a semi-infinite medium with zero refractive
index (a condition attained either when \mu= 0 or when \epsilon= 0) is known to
give full reflectivity for all incident polarizations, here we show that a gap
corresponding to \mu = 0 occurs only for TE polarized waves, whereas a gap
corresponding to \epsilon = 0 occurs only for TM polarized waves. These band
gaps are scale-length invariant and very robust against disorder, although they
may disappear for the particular case of propagation along the stratification
direction.


title:
Interpretation of cosmological expansion effects on the
  quantum-classical transition

abstract:
  Recently, what appears to be a fundamental limit associated with the size of
an object that separates the quantum behavior characterizing small objects from
the classical behavior characterizing large objects has been derived from the
Hubble velocity spread in an extended object. This threshold is now examined
further and interpreted in terms of diffusion processes in stochastic quantum
mechanics. This limiting size that separates quantum behavior from classical
behavior is shown to correspond approximately to the diffusion distance of the
object over the Hubble time.


title: Validation of internal rating systems and PD estimates

abstract:
  This paper elaborates on the validation requirements for rating systems and
probabilities of default (PDs) which were introduced with the New Capital
Standards (Basel II). We start in Section 2 with some introductory remarks on
the topics and approaches that will be discussed later on. Then we have a view
on the developments in banking regulation that have enforced the interest of
the public in validation techniques. When doing so, we put the main emphasis on
the issues with quantitative validation. The techniques discussed here could be
used in order to meet the quantitative regulatory requirements. However, their
appropriateness will depend on the specific conditions under which they are
applied. In order to have a common ground for the description of the different
techniques, we introduce in Section 3 a theoretical framework that will be the
basis for the further considerations. Intuitively, a good rating system should
show higher probabilities of default for the less creditworthy rating grades.
Therefore, in Section 4, we discuss how this monotonicity property is reflected
in the theoretical framework from Section 3. In Section 5, we study the meaning
of discriminatory power and some tools for measuring it in some detail. We will
see that there are tools that might be more appropriate than others for the
purpose of regulatory validation of discriminatory power. The topic in Section
6 is calibration of rating systems. We introduce some of the tests that can be
used for checking correct calibration and discuss the properties of the
different tests. We then conclude in Section 7 with some comments on the
question which tools might be most appropriate for quantitative validation of
rating systems and probabilities of default.


title: Unruh effect in a waveguide

abstract:
  Here we demonstrate that photons launched into a specially designed
metamaterial waveguide act as massive quasi-particles, which experience strong
acceleration. Laser light propagating through such a waveguide may be used as a
thermometer which would measure the Unruh temperature. Moreover, the
metamaterial waveguide design may be approximated by a tapered optical
waveguide.


title: Liquid Transport Due to Light Scattering

abstract:
  Using experiments and theory, we show that light scattering by
inhomogeneities in the index of refraction of a fluid can drive a large-scale
flow. The experiment uses a near-critical, phase-separated liquid, which
experiences large fluctuations in its index of refraction. A laser beam
traversing the liquid produces a large-scale deformation of the interface and
can cause a liquid jet to form. We demonstrate that the deformation is produced
by a scattering-induced flow by obtaining good agreements between the measured
deformations and those calculated assuming this mechanism.


title:
Computation of a combined spherical-elastic and viscous-half-space earth
  model for ice sheet simulation

abstract:
  This report starts by describing the continuum model used by Lingle & Clark
(1985) to approximate the deformation of the earth under changing ice sheet and
ocean loads. That source considers a single ice stream, but we apply their
underlying model to continent-scale ice sheet simulation. Their model combines
Farrell's (1972) elastic spherical earth with a viscous half-space overlain by
an elastic plate lithosphere. The latter half-space model is derivable from
calculations by Cathles (1975). For the elastic spherical earth we use
Farrell's tabulated Green's function, as do Lingle & Clark. For the half-space
model, however, we propose and implement a significantly faster numerical
strategy, a spectral collocation method (Trefethen 2000) based directly on the
Fast Fourier Transform. To verify this method we compare to an integral formula
for a disc load. To compare earth models we build an accumulation history from
a growing similarity solution from (Bueler, et al.~2005) and and simulate the
coupled (ice flow)-(earth deformation) system. In the case of simple isostasy
the exact solution to this system is known. We demonstrate that the magnitudes
of numerical errors made in approximating the ice-earth system are
significantly smaller than pairwise differences between several earth models,
namely, simple isostasy, the current standard model used in ice sheet
simulation (Greve 2001, Hagdorn 2003, Zweck & Huybrechts 2005), and the Lingle
& Clark model. Therefore further efforts to validate different earth models
used in ice sheet simulations are, not surprisingly, worthwhile.


title:
Humidity's influence on visible region refractive index structure
  parameter $C_n^2$

abstract:
  In the infrared and visible bandpass, optical propagation theory
conventionally assumes that humidity does not contribute to the effects of
atmospheric turbulence on optical beams. While this assumption may be
reasonable for dry locations, we demonstrate in this paper that there is an
unequivocal effect due to the pre sence of humidity upon the strength of
turbulence parameter, $C_n^2$, from data collected in the Chesapeake Bay area
over 100-m length horizontal propagation paths. We describe and apply a novel
technique, Hilbert Phase Analysis, to the relative humidity, temperature and
$C_n^2$ data to show the contribution of the re levant climate variable to
$C_n^2$ as a function of time.


title: Evolutionary Markovian Strategies in 2 x 2 Spatial Games

abstract:
  Evolutionary spatial 2 x 2 games between heterogeneous agents are analyzed
using different variants of cellular automata (CA). Agents play repeatedly
against their nearest neighbors 2 x 2 games specified by a rescaled payoff
matrix with two parameteres. Each agent is governed by a binary Markovian
strategy (BMS) specified by 4 conditional probabilities [p_R, p_S, p_T, p_P]
that take values 0 or 1. The initial configuration consists in a random
assignment of "strategists" among the 2^4= 16 possible BMS. The system then
evolves within strategy space according to the simple standard rule: each agent
copies the strategy of the neighbor who got the highest payoff. Besides on the
payoff matrix, the dominant strategy -and the degree of cooperation- depend on
i) the type of the neighborhood (von Neumann or Moore); ii) the way the
cooperation state is actualized (deterministically or stochastichally); and
iii) the amount of noise measured by a parameter epsilon. However a robust
winner strategy is [1,0,1,1].


title:
Measurement and simulation of the neutron response of the Nordball
  liquid scintillator array

abstract:
  The response of the liquid scintillator array Nordball to neutrons in the
energy range 1.5 < T_n < 10 MeV has been measured by time of flight using a
252Cf fission source. Fission fragments were detected by means of a thin-film
plastic scintillator. The measured differential and integral neutron detection
efficiencies agree well with predictions of a Monte Carlo simulation of the
detector which models geometry accurately and incorporates the measured,
non-linear proton light output as a function of energy. The ability of the
model to provide systematic corrections to photoneutron cross sections,
measured by Nordball at low energy, is tested in a measurement of the two-body
deuteron photodisintegration cross section in the range E_gamma=14-18 MeV.
After correction the present 2H(gamma,n)p measurements agree well with a
published evaluation of the large body of 2H(gamma,p)n data.


title:
The Apparent Madness of Crowds: Irrational collective behavior emerging
  from interactions among rational agents

abstract:
  Standard economic theory assumes that agents in markets behave rationally.
However, the observation of extremely large fluctuations in the price of
financial assets that are not correlated to changes in their fundamental value,
as well as the extreme instance of financial bubbles and crashes, imply that
markets (at least occasionally) do display irrational behavior. In this paper,
we briefly outline our recent work demonstrating that a market with interacting
agents having bounded rationality can display price fluctuations that are {\em
quantitatively} similar to those seen in real markets.


title: Order Reductions of "Predictive Dynamical Systems"

abstract:
  It has been recently pointed out that dynamical systems depending on future
values of the unknowns may be useful in different areas of knowledge. We
explore in this context the extension of the concept of order reduction that
has been useful with singular and delay differential equations in
electrodynamics and general relativity. We discuss some general properties of
order reductions in this new context and explore a method of successive
approximations, which among other things is used to check and improve the
``extrapolate prediction'' and ``fixed rate prediction'' methods.


title: Axial localization of luminophores by partial coherence interferometry

abstract:
  We propose a solution for increasing the axial resolution of confocal
microscopes. In the experimental set-up described in this paper an interference
phenomenon between two counterpropagating beams is used to determine the axial
position of a luminophore. The optical path difference between the two waves,
which is related to the position of the luminophore, is recovered thanks to a
second interferometer by using partial coherence interferometry demodulation
technique. The proposed solution can find applications in biology for
localizing with nanometric resolution a small number of tagged species.


title:
Far-field radiation pattern in Coherent Anti-stokes Raman Scattering
  (CARS) Microscopy

abstract:
  Far field radiation pattern under tight focusing condition is investigated in
Coherent Anti-stokes Raman Scattering (CARS) microscopy both in the forward
(F-CARS) and backward (E-CARS) directions. While we assume no refraction index
mismatch between the sample and the environing medium, our rigorous numerical
electromagnetic computation takes into account the exact polarizations of the
excitation laser beams and of the induced nonlinear dipoles. F-CARS and E-CARS
radiation patterns, as well as their divergence, are studied as a function of
the size of the sample object and compared to the excitation beams.


title:
A binuclear atom -- a special type of close bound state between proton
  and heavy atom

abstract:
  It is established within the Thomas -- Fermi model that a bound state of a
proton with a heavy atom should exist. On the one hand, the electrons of the
atom screen the proton's field. This decreases the repulsion force between the
proton and the nucleus. On the other hand, the attraction force between the
proton and the electrons is directed towards the gradient of the electron
density, i. e. towards the nucleus. For instance, for Z=80 both forces become
equal at approximately 0.6a where a is the Bohr radius. The corresponding
minimum of the proton potential energy is in the region of negative energies
(attraction) that can be of the order of several tens of eV. We propose to call
such a system a binuclear atom.
  In contrast to the molecules where a coupling with a hydrogen atom is due to
an essential modification of one or several states of the outer electrons the
formation of a binuclear atom is a result of collective response of the whole
system of inner electrons to the screened potential of a proton that is well
inside the electron system of the heavy atom. The variation of the wave
function of each electron can be considered as a small perturbation. The bound
state is formed as a result of joint action of a large number of perturbed
inner electrons. The important problem concerning the accuracy of our
calculation within the Thomas -- Fermi model is discussed.


title:
The $H_3^+$ molecular ion in a magnetic field in linear parallel
  configuration

abstract:
  A first detailed study of the ground state of the H$_3^+$ molecular ion in
linear configuration, parallel to a magnetic field direction, and its low-lying
$\Si,\Pi,\De$ states is carried out for magnetic fields $B=0-4.414 \times
10^{13} $G in the Born-Oppenheimer approximation. The variational method is
employed with a single trial function which includes electronic correlation in
the form $\exp{(\ga r_{12})}$, where $\ga$ is a variational parameter. It is
shown that the quantum numbers of the state of the lowest total energy (ground
state) depend on the magnetic field strength. The ground state evolves from the
spin-singlet ${}^1\Si_g$ state for weak magnetic fields $B \lesssim 5 \times
10^{8} $G to a weakly-bound spin-triplet ${}^3\Si_u$ state for intermediate
fields and, eventually, to a spin-triplet $^3\Pi_u$ state for $5 \times 10^{10}
\lesssim B \lesssim 4.414 \times 10^{13} $G. Local stability of the linear
parallel configuration with respect to possible small deviations is checked.

categories: physics.atom-ph astro-ph cond-mat.str-el physics.chem-ph


title:
Intermittent dynamics, strong correlations, and bit-error-rate in
  multichannel optical fiber communication systems

abstract:
  We investigate the effects of delayed Raman response on pulse dynamics in
massive multichannel optical fiber communication systems. Taking into account
the stochastic nature of pulse sequences in different frequency channels and
the Raman induced energy exchange in pulse collisions we show that the pulse
parameters exhibit intermittent dynamic behavior, and that the pulse amplitudes
exhibit relatively strong and long-range correlations. Moreover, we find that
the Raman-induced cross frequency shift is the main intermittency-related
mechanism leading to bit pattern deterioration and evaluate the bit-error-rate
of the system.


title:
A Unified Framework for the Pareto Law and Matthew Effect using
  Scale-Free Networks

abstract:
  We investigate the accumulated wealth distribution by adopting evolutionary
games taking place on scale-free networks. The system self-organizes to a
critical Pareto distribution (1897) of wealth $P(m)\sim m^{-(v+1)}$ with $1.6 <
v <2.0$ (which is in agreement with that of U.S. or Japan). Particularly, the
agent's personal wealth is proportional to its number of contacts
(connectivity), and this leads to the phenomenon that the rich gets richer and
the poor gets relatively poorer, which is consistent with the Matthew Effect
present in society, economy, science and so on. Though our model is simple, it
provides a good representation of cooperation and profit accumulation behavior
in economy, and it combines the network theory with econophysics.


title: Urban Traffic Dynamics: A Scale-Free Network Perspective

abstract:
  This letter propose a new model for characterizing traffic dynamics in
scale-free networks. With a replotted road map of cities with roads mapped to
vertices and intersections to edges, and introducing the road capacity L and
its handling ability at intersections C, the model can be applied to urban
traffic system. Simulations give the overall capacity of the traffic system
which is quantified by a phase transition from free flow to congestion.
Moreover, we report the fundamental diagram of flow against density, in which
hysteresis is found, indicating that the system is bistable in a certain range
of vehicle density. In addition, the fundamental diagram is significantly
different from single-lane traffic model and 2-D BML model with four states:
free flow, saturated flow, bistable and jammed.


title: Weighted Network of Chinese Nature Science Basic Research

abstract:
  Using the requisition papers of Chinese Nature Science Basic Research in
management and information department, we construct the weighted network of
research areas({\bf WRAN}) represented by the subject codes. In WRAN, two
research areas are considered connected if they have been filled in at least
one requisition paper. The edge weight is defined as the number of requisition
papers which have filled in the same pairs of codes. The node strength is
defined as the number of requisition papers which have filled in this code,
including the papers which have filled in it only. Here we study a variety of
nonlocal statistics for these networks, such as typical distances between
research areas through the network, and measures of centrality such as
betweenness. These statistics characteristics can illuminate the global
development trend of Chinese scientific study, it is also helpful to adjust the
code system to reflect the real status more accurately. Finally, we present a
plausible model for the formation and structure of networks with the observed
properties.


title:
Relationship Between Structural Characters and Synchronizability of
  Scale-free Networks

abstract:
  Using Memory Tabu Search(MTS) algorithm, we investigate the relationship
between structural characters and synchronizability of scale-free networks by
maximizing and minimizing the ratio $Q$ of the eigenvalues of the coupling
matrix by edge-intercrossing procedures. The numerical results indicate that
clustering coefficient $C$, maximal betweenness $B_{max}$ are two most
important factors to scale-free network synchronizability, and assortative
coefficient $r$ and average distance $D$ are the secondary ones. Moreover, the
average degree $<k>$ affects the relationship between above structural
characters and synchronizability of scale-free networks, and the minimal $Q$
decreases when $<k>$ increases.


title: Simple nonstationary generalization of Gaussian Shell-model beams

abstract:
  Model of partially coherent pulses, based on the concept of "hidden
coherence", introduced recently by Picozzi and Haelterman in framework of
parametric wave mixing, is presented. The nonuiform and nonstationary phase
shift, while completely deterministic, results in the beam properties, which
are typical for partially coherent light - low contrast of interference
effects, increase of spectral width and so on - i. e. light becomes effectively
non-coherent. The proposed model is studied in framework of coherent mode
decomposition, its main properties and limitations of the model are discussed.


title: Dynamics of a deformable body in a fast flowing soap film

abstract:
  We study the behavior of an elastic loop embedded in a flowing soap film.
This deformable loop is wetted into the film and is held fixed at a single
point against the oncoming flow. We interpret this system as a two-dimensional
flexible body interacting in a two-dimensional flow. This coupled
fluid-structure system shows bistability, with both stationary and oscillatory
states. In its stationary state, the loop remains essentially motionless and
its wake is a von K\'arm\'an vortex street. In its oscillatory state, the loop
sheds two vortex dipoles, or more complicated vortical structures, within each
oscillation period. We find that the oscillation frequency of the loop is
linearly proportional to the flow velocity, and that the measured Strouhal
numbers can be separated based on wake structure.


title: Detailed instantaneous ionization rate of H$_2^+$ in intense laser field

abstract:
  Component instantaneous ionization rate (IIR) is introduced and the approach
of its calculation is formulated. The component IIR's and the overall
(time-averaged) component ionization rates are calculated for H$_2^+$ at
different values of inter-nuclear distance in a linearly polarized laser field
with $1.0 \times10^{14}$W cm$^{-2}$ intensity and $\lambda \sim 1064 $nm
wavelength by direct numerical solution of the fixed-nuclei full dimensional
time-dependent Schr \"odinger equation. The exact overall component ionization
rates calculated by time-averaging of the component IIR are compared with those
calculated approximately via the virtual detector method (VD). Details of the
time dependent behavior of the outgoing and incoming electron wavepackets of
the H$_2^+$ system in intense laser field at sub-femtosecond time scale are
studied based on the calculated component IIR. It is shown clearly that the
positive (outgoing electron wavepacket) signals of the IIR and its z component
are strong and sharp but the negative (returning electron wavepacket) signals
of the IIR are smooth and weak. The structure of the $\rho$ component of the
IIR has smooth structure. Relation between the R-dependent ionization rate and
duration of the ramp of the laser pulse is studied and it is explicitly shown
that for internuclear distance R<5.6, when the laser pulse is turned on without
a ramp, the first peak of R-dependent ionization rates moves towards the peak
of the lower time dependent Floquet quasi-energy state (QES).


title: Relativistic Electron Beam Slicing by Wakefiled in Plasmas

abstract:
  A method of slicing of high-energy electron beams following their interaction
with the transverse component of the wakefield left in a plasma behind a high
intensity ultra short laser pulse is proposed. The transverse component of the
wakefield focuses a portion of the electron bunch, which experiences betatron
oscillations. The length of the focused part of the electron bunch can be made
substantially less than the wakefield wavelength.


title: Non-dipole angular anisotropy parameters of semi-filled shell atoms

abstract:
  We present the results of calculations of outer shell non-dipole angular
anisotropy parameters for semi-filled shell atoms in the Hartree-Fock (HF)
one-electron approximation and with account of inter-electron correlations in
the frame of the Spin Polarized Random Phase Approximation with Exchange (SP
RPAE). We demonstrate for the first time that this characteristic of
photoionization process is essentially sensitive to the fact whether the
photoelectron has the same or opposite spin orientation to that of the
semi-filled shell.


title:
Controlling high-harmonic generation and above-threshold ionization with
  an attosecond-pulse train

abstract:
  We perform a detailed analysis of how high-order harmonic generation (HHG)
and above-threshold ionization (ATI) can be controlled by a time-delayed
attosecond-pulse train superposed to a strong, near-infrared laser field. In
particular we show that the high-harmonic and photoelectron intensities, the
high-harmonic plateau structure and cutoff energies, and the ATI angular
distributions can be manipulated by changing this delay. This is a direct
consequence of the fact that the attosecond pulse train can be employed as a
tool for constraining the instant an electronic wave packet is ejected in the
continuum. A change in such initial conditions strongly affects its subsequent
motion in the laser field, and thus HHG and ATI. In our studies, we employ the
Strong-Field Approximation and explain the features observed in terms of
interference effects between various electron quantum orbits. Our results are
in agreement with recent experimental findings and theoretical studies
employing purely numerical methods.


title:
Comparison Tests of Variable-Stepsize Algorithms for Stochastic Ordinary
  Differential Equations of Finance

abstract:
  Since the introduction of the Black-Scholes model stochastic processes have
played an increasingly important role in mathematical finance. In many cases
prices, volatility and other quantities can be modeled using stochastic
ordinary differential equations. Available methods for solving such equations
have until recently been markedly inferior to analogous methods for
deterministic ordinary differential equations. Recently, a number of methods
which employ variable stepsizes to control local error have been developed
which appear to offer greatly improved speed and accuracy. Here we conduct a
comparative study of the performance of these algorithms for problems taken
from the mathematical finance literature.


title:
Negative refraction and sub-wavelength imaging using transparent
  metal-dielectric stacks

abstract:
  Negative refraction is known to occur in materials that simultaneously
possess a negative electric permittivity and magnetic permeability; hence they
are termed negative index materials. However, there are no known natural
materials that exhibit a negative index of refraction. In large part, interest
in these materials is due to speculation that they could be used as perfect
lenses with superresolution. We propose a new way of achieving negative
refraction with currently available technology, based on transparent,
metallo-dielectric multilayer structures. The advantage of these structures is
that both tunability and transmission (well above 50%) can be achieved in the
visible wavelength regime. We demonstrate both negative refraction and
superresolution in these structures. Our findings point to a simpler way to
fabricate a material that exhibits negative refraction. This opens up an
entirely new path not only for negative refraction, but also to expand the
exploration of wave propagation effects in metals.


title: Synthesis of unilateral radiators

abstract:
  A radiator is typically a parabolic mirror illuminated by an electromagnetic
source, or a cylindrical transducer of resonant vibrations. Both of these
devices are designed to radiate either a beam of parallel rays or a (focused)
beam that converges to a point or a line. Consequently, at the worst, the
radiation pattern is largely restricted to a {\it half space}, and at the best,
to a cone or cylinder-like subspace of this half space. Such devices can
therefore be termed unilateral radiators. This study is devoted to the
synthesis of the sources that can give rise to such radiation, the underlying
motivation being the removal of the material presence of the mirror or
transducer casing from which waves coming from other boundaries could reflect
or diffract.


title:
Short wavelength quantum electrodynamical correction to cold plasma-wave
  propagation

abstract:
  The effect of short wavelength quantum electrodynamic (QED) correction on
plasma-wave propagation is investigated. The effect on plasma oscillations and
on electromagnetic waves in an unmagnetized as well as a magnetized plasma is
investigated. The effects of the short wavelength QED corrections are most
significant for plasma oscillations and for extraordinary modes. In particular,
the QED correction allow plasma oscillations to propagate, and the
extra-ordinary mode looses its stop band. The significance of our results is
discussed.


title: Technical Note on POlarimetric Phase Interferometry (POPI)

abstract:
  The Global Navigation Satellite Systems (GNSS), such as the American Global
Positioning System (GPS), the Russian GLONASS or the imminent European Galileo,
can be used as sources of opportunity for remote sensing of the Oceans. In this
document, we present the approach, conceptual background and preliminary
results of a novel polarimetric interferometric technique based on GPS signals
rebounded off of the sea surface and collected at both Right Hand (RH) and Left
Hand (LH) Circular Polarizations. We seek to obtain geophysical information out
of the phase information, which could be in principle relate to the dielectric
properties of the sea surface.


title: Spectroscopy of Rb$_{2}$ dimers in solid $^{4}$He

abstract:
  We present experimental and theoretical studies of the absorption, emission
and photodissociation spectra of Rb$_{2}$ molecules in solid helium. We have
identified 11 absorption bands of Rb$_{2}$. All laser-excited molecular states
are quenched by the interaction with the He matrix. The quenching results in
efficient population of a metastable (1)$^{3}\Pi_{u}$ state, which emits
fluorescence at 1042 nm. In order to explain the fluorescence at the forbidden
transition and its time dependence we propose a new molecular exciplex
Rb$_{2}(^{3}\Pi_{u})$He$_{2}$. We have also found evidence for the formation of
diatomic bubble states following photodissociation of Rb$_{2}$.


title:
Clock rates, clock settings and the physics of the space-time Lorentz
  transformation

abstract:
  A careful study is made of the operational meaning of the time symbols
appearing in the space-time Lorentz transformation. Four distinct symbols, with
different physical meanings, are needed to describe reciprocal measurements
involving stationary and uniformly-moving clocks. Physical predictions concern
only the observed rate of a clock as a function of its relative speed, not its
setting. How the failure to make this distinction leads to the conventional
predictions of spurious `relativity of simultaneity' and `length contraction'
effects in special relativity is explained.


title:
Exploration of electronic quadrupole states in atomic clusters by
  two-photon processes

abstract:
  We analyze particular two-photon processes as possible means to explore
electronic quadrupole states in free small deformed atomic clusters. The
analysis is done in the time-dependent local density approximation (TDLDA). It
is shown that the direct two-photon population (DTP) and off-resonant
stimulated Raman (ORSR) scattering can be effectively used for excitation of
the quadrupole states in high-frequency (quadrupole plasmon) and low-frequency
(infrared) regions, respectively. In ORSR, isolated dipole particle-hole states
as well as the tail of the dipole plasmon can serve as an intermediate state. A
simultaneous study of low- and high-frequency quadrupoles, combining DTP and
ORSR, is most effective. Femtosecond pulses with intensities $I = 2\cdot
10^{10} - 2\cdot 10^{11} W/cm^2$ and pulse durations $T = 200 - 500$ fs are
found to be optimal. Since the low-lying quadrupole states are dominated by one
single electron-hole pair, their energies, being combined with the
photoelectron data for hole states, allow to get the electron spectrum above
the Fermi level and thus greatly extend our knowledge on the single particle
spectra of clusters. Besides, the developed schemes allow to estimate the
lifetime of the quadrupole states.


title: The simplest derivation of the Lorentz transformation

abstract:
  Starting from the well-known light-clock thought experiment to derive time
dilation and length contraction, it is shown that finding the Lorentz
Transformation requires nothing more than the most trivial vector addition
formula. The form which is obtaine for the L.T. allows an easy derivation of
the velocity and acceleration transformations which are also given.


title: Status of a DEPFET pixel system for the ILC vertex detector

abstract:
  We have developed a prototype system for the ILC vertex detector based on
DEPFET pixels. The system operates a 128x64 matrix (with ~35x25 square micron
large pixels) and uses two dedicated microchips, the SWITCHER II chip for
matrix steering and the CURO II chip for readout. The system development has
been driven by the final ILC requirements which above all demand a detector
thinned to 50 micron and a row wise read out with line rates of 20MHz and more.
The targeted noise performance for the DEPFET technology is in the range of
ENC=100 e-. The functionality of the system has been demonstrated using
different radioactive sources in an energy range from 6 to 40keV. In recent
test beam experiments using 6GeV electrons, a signal-to-noise ratio of S/N~120
has been achieved with present sensors being 450 micron thick. For improved
DEPFET systems using 50 micron thin sensors in future, a signal-to-noise of 40
is expected.


title: Random lasing in weakly scattering systems

abstract:
  We present detailed experimental and numerical studies of random lasing in
weakly scattering systems. The interference of scattered light, which is weak
in the passive systems, is greatly enhanced in the presence of high gain,
providing coherent and resonant feedback for lasing. The lasing modes are
confined in the vicinity of the pumped volume due to absorption of emitted
light outside it. In the ballistic regime where the size of gain volume is less
than the scattering mean free path, lasing oscillation occurs along the
direction in which the gain volume is most extended, producing directional
laser output. The feedback for lasing originates mainly from backscattering of
particles near the boundaries of pumped region. It results in nearly constant
frequency spacing of lasing modes, which scales inversely with the maximum
dimension of the gain volume.


title:
Kolmogorov and Irosnikov-Kraichnan scaling in the anisotropic turbulent
  solar wind

abstract:
  Solar wind turbulence is dominated by Alfv\'{e}nic fluctuations but the power
spectral exponents somewhat surprisingly evolve toward the Kolmogorov value of
-5/3, that of hydrodynamic turbulence. We show that at 1AU the turbulence
decomposes linearly into two coexistent components perpendicular and parallel
to the local average magnetic field. The first of these is consistent with
propagating Alfv\'{e}n wavepackets and shows the scaling expected of
Alfv\'{e}nic turbulence, namely Irosnikov- Kraichnan. The second shows
Kolmogorov scaling which we also find in the number and magnetic energy
density, and Poynting flux.


title:
Statistical mechanics of socio-economic systems with heterogeneous
  agents

abstract:
  We review the statistical mechanics approach to the study of the emerging
collective behavior of systems of heterogeneous interacting agents. The general
framework is presented through examples is such contexts as ecosystem dynamics
and traffic modeling. We then focus on the analysis of the optimal properties
of large random resource-allocation problems and on Minority Games and related
models of speculative trading in financial markets, discussing a number of
extensions including multi-asset models, Majority Games and models with
asymmetric information. Finally, we summarize the main conclusions and outline
the major open problems and limitations of the approach.


title: Electrodynamics of a non-relativistic, non-equilibrium plasma

abstract:
  A non-equilibrium plasma was studied using classical electrodynamic field
theory. Non-linear interaction terms contribute to a finite lifetime for the
dressed electrodynamic field. The lifetime exhibits a $\sim n^{-1} T_{e}^{3/2}
T_{i}^{-2}T_{r}^{1/2}$ dependence, where $n$ is the number density, $T_{e}$ is
the electron temperature, $T_{i}$ is the ion temperature, and $T_{r}$ is the
temperature of the radiation field. The resulting width of the plasmon
resonance is shown to decrease as equilibrium is approached. Dynamic screening
leads to opaqueness of the plasma for low energy electromagnetic radiation.
This leads to a quadratic correction to the quartic Stefan-Boltzmann law. We
also briefly discuss the effect of dynamic screening on fusion rates. Solitonic
solutions to our non-linear wave equation allow localization of positive
charges, which may enhance fusion rates.


title: Electromagnetics from a quasistatic perspective

abstract:
  Quasistatics is introduced so that it fits smoothly into the standard
textbook presentation of electrodynamics. The usual path from statics to
general electrodynamics is rather short and surprisingly simple. A closer look
reveals however that it is not without confusing issues as has been illustrated
by many contributions to this Journal. Quasistatic theory is conceptually
useful by providing an intermediate level in between statics and the full set
of Maxwell's equations. Quasistatics is easier than general electrodynamics and
in some ways more similar to statics. It is however, in terms of interesting
physics and important applications, far richer than statics. Quasistatics is
much used in electromagnetic modeling, an activity that today is possible on a
PC and which also has great pedagogical potential. The use of electromagnetic
simulations in teaching gives additional support for the importance of
quasistatics. This activity may also motivate some change of focus in the
presentation of basic electrodynamics.


title:
Assembly and measurements of the Electromagnetic Calorimeter components
  for "WASA at COSY" setup

abstract:
  This work describes the tests of the scintillator electromagnetic calorimeter
of theWASA detector setup after transferring it from the CELSIUS storage ring
at The Svedberg Laboratory(Uppsala, Sweden) to the Cooler Synchrotron COSY at
the Institut fur Kernphysik (IKP) of Forschungszentrum Julich, Germany. The
tests were performed using gammas of 4.4MeV energy from an AmBe source. The
status of the CsI(Na) crystals was determined and the indication of gain factor
for the energy calibration was extracted.


title:
Wideband pulse propagation: single-field and multi-field approaches to
  Raman interactions

abstract:
  We model the process of ultra broadband light generation in which a pair of
laser pulses separated by the Raman frequency drive a Raman transition. In
contrast to the usual approach using separate field envelopes for the different
frequency components, we treat the field as a single entity. This requires the
inclusion of few-cycle corrections to the pulse propagation. Our single-field
model makes fewer approximations and is mathematically (and hence
computationally) simpler, although it does require greater computational
resources to implement. The single-field theory reduces to the traditional
multi-field one using appropriate approximations.


title:
Wideband pulse propagation: a detailed calculation including Raman
  processes

abstract:
  I present a detailed derivation of wideband optical pulses interacting with a
Raman transition in the kind of scheme currently used to generate the ultra
broadband light fields needed to create ultrashort pulses. In contrast to the
usual approach using separate field envelopes for the pump, Stokes, and
anti-Stokes spectral lines, I use a single field envelope. This requires the
inclusion of few-cycle corrections to the pulse propagation. The single-field
model makes fewer approximations and is mathematically (and hence
computationally) simpler, although it does require greater computational
resources to implement. The single-field theory reduces to the traditional
multi-field one using appropriate approximations.


title: A complexity measure for symbolic sequences and applications to DNA

abstract:
  We introduce a complexity measure for symbolic sequences. Starting from a
segmentation procedure of the sequence, we define its complexity as the entropy
of the distribution of lengths of the domains of relatively uniform composition
in which the sequence is decomposed. We show that this quantity verifies the
properties usually required for a ``good'' complexity measure. In particular it
satisfies the one hump property, is super-additive and has the important
property of being dependent of the level of detail in which the sequence is
analyzed. Finally we apply it to the evaluation of the complexity profile of
some genetic sequences.


title: Approximate Equations for Large Scale Atmospheric Motions

abstract:
  A systematic derivation of a set of equations governing large scale
atmospheric motions is presented. They are derived by introducing new variables
scaled in terms of a small parameter.The solution is expanded in powers of this
parameter.This leads to the hydrostatic pressure and geostrophic wind
equations.The resulting set of equations is similar to that proposed by J.
Charney.


title: Long-range memory model of trading activity and volatility

abstract:
  Earlier we proposed the stochastic point process model, which reproduces a
variety of self-affine time series exhibiting power spectral density S(f)
scaling as power of the frequency f and derived a stochastic differential
equation with the same long range memory properties. Here we present a
stochastic differential equation as a dynamical model of the observed memory in
the financial time series. The continuous stochastic process reproduces the
statistical properties of the trading activity and serves as a background model
for the modeling waiting time, return and volatility. Empirically observed
statistical properties: exponents of the power-law probability distributions
and power spectral density of the long-range memory financial variables are
reproduced with the same values of few model parameters.


title:
Extra Dimensions, Brane Worlds, and the Vanishing of Axion Contributions
  to Inflation?

abstract:
  We examine from first principles the implications of the 5th Randall-Sundrum
Brane world dimension in terms of setting initial conditions for chaotic
inflationary physics. Our model pre supposes that the inflationary potential
pioneered by Guth is equivalent in magnitute in its initial inflationary state
to the effective potential presented in the Randall-Sundrum model. We also
consider an axion contribution to chaotic inflation(which may have a
temperature dependence) which partly fades out up to the point of chaotic
inflation being matched to a Randall-Sundrum effective potential. If we reject
an explicitly axion mass drop off to infinitesimal values at high temperatures,
we may use the Bogomolnyi inequality to rescale and re set initial conditions
for the chaotic inflationary potential. One of the potential systems embedded
in the Randall-Sundrum brane world is a model with a phase transition bridge
from a tilted wasboard potiential to the chaotic inflationary model pioneered
by Guth which is congruent with the slow roll criteria. If, as written up
earlier, the axion wall contribution is due to di-quarks,this is equivalent to
tying in baryogenesis to the formation of chaotic inflation initial conditions,
with the Randall-Sundrum brane world effective dileneating the end of the
dominant role of di-quarks, and the beginning of inflation.


title: The Pioneer Anomaly and a Machian Universe

abstract:
  We discuss astronomical and astrophysical evidence, which we relate to the
principle of zero-total energy of the Universe, that imply several relations
among the mass M, the radius R and the angular momentum L of a "large" sphere
representing a Machian Universe. By calculating the angular speed, we find a
peculiar centripetal acceleration for the Universe. This is an ubiquituous
property that relates one observer to any observable. It turns out that this is
exactly the anomalous acceleration observed on the Pioneers spaceships. We have
thus, shown that this anomaly is to be considered a property of the Machian
Universe. We discuss several possible arguments against our proposal.


title:
Electron density diagnostic potential of Ar XIV soft X-ray emission
  lines

abstract:
  Theoretical electron density-sensitive line ratios $R_1 - R_6$ of Ar XIV soft
X-ray emission lines are presented. We found that these line ratios are
sensitive to electron density $n_e$, and the ratio $R_1$ is insensitive to
electron temperature $T_e$. Recent work has shown that accurate atomic data,
such as electron impact excitation rates, is very important for reliable
determination of the electron density of laboratory and astrophysical plasmas.
Present work indicates that the maximum discrepancy of line ratios introduced
from different atomic data calculated with distorted wave and R-matrix
approximations, is up to 18% in the range of $n_e=10^{9-13}$cm$^{-3}$. By
comparison of these line ratios with experiment results carried out in electron
beam ion trap (EBIT-II), electron density of the laboratory plasma is
diagnosed, and a consistent result is obtained from $R_1$, $R_2$ and $R_3$. Our
result is in agreement with that diagnosed by Chen et al using triplet of N VI.
A relative higher diagnosed electron density from $R_2$ is due to its weak
sensitivity to electron temperature. A better consistency at lower $T_e$
indicates that temperature of the laboratory plasma is lower than
log$T_e$(K)=6.5. Comparison between the measured and theoretical ratios reveals
that 32.014~\AA line is weakly blended by lines from other Ar ions, while
30.344~\AA line is strongly contaminated.


title: Controlling absorption resonances from sub-wavelength cylinder arrays

abstract:
  The absorption and extinction spectra of sub-wavelength cylinder arrays are
shown to present two different kind of resonances. Close to the Rayleigh
anomalies, the diffractive coupling with the lattice periodicity leads to sharp
peaks in the extinction spectra with characteristic Fano line shapes for both s
and p-polarizations. When the material exhibits an absorption line or in the
presence of localized surface plasmon/polaritons, the system is shown to
present resonant absorption with wider and symmetric line shapes. For
s-polarization our analysis predicts a theoretical limit of 50 % of absorption.
Interestingly, for p-polarized light and an appropriate choice of parameters,
subwavelength cylinder arrays can present perfect (100 %) absorption.


title: A note about the ground state of the hydrogen molecule

abstract:
  A trial function is presented for the $H_2$ molecule which provides the most
accurate (the lowest) Bohr-Oppenheimer ground state energy among few-parametric
trial functions (with $\leq 14$ parameters). It includes the electronic
correlation term in the form $\sim \exp{(\gamma r_{12})}$ where $\gamma$ is a
variational parameter.


title: Optothermal Molecule Trap

abstract:
  Thermophoresis moves molecules along temperature gradients, typically from
hot to cold. We superpose fluid flow with thermophoretic molecule flow under
well defined microfluidic conditions, imaged by fluorescence microscopy. DNA is
trapped and accumulated 16-fold in regions where both flows move in opposite
directions. Strong 800-fold accumulation is expected, however with slow
trapping kinetics. The experiment is equally described by a three-dimensional
and one-dimensional analytical model. As an application, we show how a radially
converging temperature field confines short DNA into a 10 um small spot.


title:
Paradox of inductionless magnetorotational instability in a
  Taylor-Couette flow with a helical magnetic field

abstract:
  We consider the magnetorotational instability (MRI) of a hydrodynamically
stable Taylor-Couette flow with a helical external magnetic field in the
inductionless approximation defined by a zero magnetic Prandtl number
($\Pm=0)$. This leads to a considerable simplification of the problem
eventually containing only hydrodynamic variables. First, we point out that the
energy of any perturbation growing in the presence of magnetic field has to
grow faster without the field. This is a paradox because the base flow is
stable without the magnetic while it is unstable in the presence of a helical
magnetic field without being modified by the latter as it has been found
recently by Hollerbach and Rudiger [Phys. Rev. Lett. 95, 124501 (2005)]. We
revisit this problem by using a Chebyshev collocation method to calculate the
eigenvalue spectrum of the linearized problem. In this way, we confirm that MRI
with helical magnetic field indeed works in the inductionless limit where the
destabilization effect appears as an effective shift of the Rayleigh line.
Second, we integrate the linearized equations in time to study the transient
behavior of small amplitude perturbations, thus showing that the energy
arguments are correct as well. However, there is no real contradiction between
both facts. The linear stability theory predicts the asymptotic development of
an arbitrary small-amplitude perturbation, while the energy stability theory
yields the instant growth rate of any particular perturbation, but it does not
account for the evolution of this perturbation.


title:
Computer assisted planning and orbital surgery: patient-related
  prediction of osteotomy size in proptosis reduction

abstract:
  BACKGROUND: Proptosis is characterized by a protrusion of the eyeball due to
an increase of the orbital tissue volume. To recover a normal eyeball
positioning, the most frequent surgical technique consists in the osteotomy of
orbital walls combined with the manual loading on the eyeball. Only a rough
clinical rule is currently available for the surgeons but it is useless for
this technique. The first biomechanical model dealing with proptosis reduction,
validated in one patient, has been previously proposed by the authors. METHODS:
This paper proposes a rule improving the pre-operative planning of the
osteotomy size in proptosis reduction. Patient-related poroelastic FE models
combined with sensitivity studies were used to propose two clinical rules to
improve the pre-operative planning of proptosis reduction. This poroelastic
model was run on 12 patients. Sensitivity studies permitted to establish
relationships between the osteotoemy size, the patient-related orbital volume,
the decompressed tissue volume and the eyeball backward displacement. FINDINGS:
The eyeball displacement and the osteotomy size were non-linearly related: an
exponential rule has been proposed. The patient-related orbital volume showed a
significant influence: a bi-quadratic analytical equation liking the osteotomy
size, the orbital volume and the targeted eyeball protrusion has been
established. INTERPRETATION: Two process rules derived from patient-related
biomechanical FE models have been proposed for the proptosis reduction
planning. The implementation of the process rules into a clinical setting is
easy since only a sagittal radiography is required. The osteotomy size can be
monitored using optical guided instruments.


title:
Measurement of mutual inductance from frequency dependence of impedance
  of AC coupled circuit using digital dual-phase lock-in amplifier

abstract:
  We present a simple method to determine the mutual inductance $M$ between two
coils in a coupled AC circuit by using a digital dual-phase lock-in amplifier.
The frequency dependence of the real and imaginary parts is measured as the
coupling constant is changed. The mutual inductance $M$ decreases as the
distance $d$ between the centers of coils is increased. We show that the
coupling constant is proportional to $d^{-n}$ with an exponent $n$ ($\approx$
3). This coupling is similar to that of two magnetic moments coupled through a
dipole-dipole interaction.


title:
Stability of an electromagnetically levitated spherical sample in a set
  of coaxial circular loops

abstract:
  This paper presents a theoretical study of oscillatory and rotational
instabilities of a solid spherical body, levitated electromagnetically in
axisymmetric coils made of coaxial circular loops. We apply our previous theory
to analyze the static and dynamic stability of the sample depending on the ac
frequency and the position of the sample in the coils for several simple
configurations. We introduce an original analytical approach employing a gauge
transformation for the vector potential. First, we calculate the spring
constants that define the frequency of small-amplitude oscillations. For static
stability, the spring constants must be positive. Dynamic instabilities are
characterized by critical ac frequencies that, when exceeded, may result either
in a spin-up or oscillations with increasing amplitude. We found that the
critical frequencies increase with the nonuniformity of the field. We show that
for a spherically harmonic field, the critical frequency for the spin-up
instability in a field of degree $l$ coincides with the critical frequency for
the oscillatory instability in a field of degree $l+1$.


title:
Atom interferometry gravity-gradiometer for the determination of the
  Newtonian gravitational constant G

abstract:
  We developed a gravity-gradiometer based on atom interferometry for the
determination of the Newtonian gravitational constant \textit{G}. The
apparatus, combining a Rb fountain, Raman interferometry and a juggling scheme
for fast launch of two atomic clouds, was specifically designed to reduce
possible systematic effects. We present instrument performances and show that
the sensor is able to detect the gravitational field induced by source masses.
A discussion of projected accuracy for \textit{G} measurement using this new
scheme shows that the results of the experiment will be significant to
discriminate between previous inconsistent values.


title: On one-dimensional models for hydrodynamics

abstract:
  To date it has not been possible to prove whether or not the
three-dimensional incompressible Euler equations develop singular behaviour in
finite time. Some possible singular scenarios, as for instance shock-waves, are
very important from a physical point of view, since they imply the connection
among the macroscopic and the microscopic scale. Therefore, the appearence of
this type of singularity or a similar one might be interpreted as a possible
explanation of the transition to turbulence. In order to clarify the question,
some one-dimensional models for ideal incompressible hydrodynamics have been
introduced and analyzed, and it was proven that shock-waves appear in finite
time within this type of flow. In this work we question the validity of these
models and analyze the physical meaning that the occurrence of a singularity in
an incompressible flow, if it happens, may have.


title:
R-matrix calculation of differential cross sections for low-energy
  electron collisions with ground and electronically excited state O2 molecules

abstract:
  Differential cross sections for electron collisions with the O$_2$ molecule
in its ground ${X}^{3}\Sigma_g^-$ state, as well as excited ${a}^{1}\Delta_g$
and ${b}^{1}\Sigma_g^+$ states are calculated. As previously, the fixed-bond
R-matrix method based on state-averaged complete active space SCF orbitals is
employed. In additions to elastic scattering of electron with the O$_2$
${X}^{3}\Sigma_g^-$, ${a}^{1}\Delta_g$ and ${b}^{1}\Sigma_g^+$ states, electron
impact excitation from the ${X}^{3}\Sigma_g^-$ state to the ${a}^{1}\Delta_g$
and ${b}^{1}\Sigma_g^+$ states as well as '6 eV states' of
${c}^{1}\Sigma_u^{-}$, ${A'}^{3}\Delta_u$ and ${A}^{3}\Sigma_u^{+}$ states is
studied. Differential cross sections for excitation to the '6 eV states' have
not been calculated previously. Electron impact excitation to the
${b}^{1}\Sigma_g^+$ state from the metastable ${a}^{1}\Delta_g$ state is also
studied. For electron impact excitation from the O$_2$ ${X}^{3}\Sigma_g^-$
state to the ${b}^{1}\Sigma_g^+$ state, our results agree better with the
experimental measurements than previous theoretical calculations. Our cross
sections show angular behaviour similar to the experimental ones for
transitions from the ${X}^{3}\Sigma_g^-$ state to the '6 eV states', although
the calculated cross sections are up to a factor two larger at large scattering
angles. For the excitation from the ${a}^{1}\Delta_g$ state to the
${b}^{1}\Sigma_g^+$ state, our results marginally agree with the experimental
data except for the forward scattering direction.


title:
Negative index metamaterial combining magnetic resonators with metal
  films

abstract:
  We present simulation results of a design for negative index materials that
uses magnetic resonators to provide negative permeability and metal film for
negative permittivity. We also discuss the possibility of using semicontinuous
metal films to achieve better manufacturability and enhanced impedance
matching.


title: On Controversies in Relativity Theory

abstract:
  Controversies arise when specialists disagree on some particular issue. This
normally occurs in any scientific brunch. We analyze some controversies, which
have a good cause in Special Relativity. The paper does not question Special
Relativity Theory but it challenges changing deeply held academic beliefs about
imaginary experiments in Special Relativity Theory.
  PACS 03.30.+p


title:
Analysis and Synthesis of the Distribution of Consonants over Languages:
  A Complex Network Approach

abstract:
  Cross-linguistic similarities are reflected by the speech sound systems of
languages all over the world. In this work we try to model such similarities
observed in the consonant inventories, through a complex bipartite network. We
present a systematic study of some of the appealing features of these
inventories with the help of the bipartite network. An important observation is
that the occurrence of consonants follows a two regime power law distribution.
We find that the consonant inventory size distribution together with the
principle of preferential attachment are the main reasons behind the emergence
of such a two regime behavior. In order to further support our explanation we
present a synthesis model for this network based on the general theory of
preferential attachment.


title:
Modeling the Co-occurrence Principles of the Consonant Inventories: A
  Complex Network Approach

abstract:
  Speech sounds of the languages all over the world show remarkable patterns of
cooccurrence. In this work, we attempt to automatically capture the patterns of
cooccurrence of the consonants across languages and at the same time figure out
the nature of the force leading to the emergence of such patterns. For this
purpose we define a weighted network where the consonants are the nodes and an
edge between two nodes (read consonants) signify their co-occurrence likelihood
over the consonant inventories. Through this network we identify communities of
consonants that essentially reflect their patterns of co-occurrence across
languages. We test the goodness of the communities and observe that the
constituent consonants frequently occur in such groups in real languages also.
Interestingly, the consonants forming these communities reflect strong
correlations in terms of their features, which indicate that the principle of
feature economy acts as a driving force towards community formation. In order
to measure the strength of this force we propose an information theoretic
definition of feature economy and show that indeed the feature economy
exhibited by the consonant communities are substantially better than those if
the consonant inventories had evolved just by chance.


title:
On O-X mode conversion in a cold magnetized 2D inhomogeneous plasma in
  the electron cyclotron frequency range

abstract:
  In this paper a reduced set of the partial differential wave equations valid
in the conversion layer close to O-mode cutoff surface and accounting for the
magnetic field 2D inhomogeneity with no restriction to an angle between the
toroidal direction and the magnetic field direction is derived. An integral
representation of a solution to the derived set of equation is given. For the
particular case of small angle between O mode cut-off surface and X mode
cut-off surface an explicit expressions for both the electric field components
and the conversion coefficients are obtained and its properties are considered
in details.


title: Accurate polynomial interpolations of special functions

abstract:
  Provided a special function of one variable and some of its derivatives can
be accurately computed over a finite range, a method is presented to build a
series of polynomial approximations of the function with a defined relative
error over the whole range. This method is easy to implement and makes possible
fast computation of special functions.