title:
The train/embankment thought experiment, Einstein's second postulate of
  special relativity and relativity of simultaneity

abstract:
  The relativistic time dilatation effect and Einstein's second postulate of
special relativity are used to analyse train/embankment thought expriments,
both Einstein's original one, and an extension where observers on two trains
moving at different speeds, as well as on the embankment, are considered.
Whereas the relativistic analysis of Einstein's experiment shows, in
contradiction to Einstein's interpretation, no `relativity of simultaneity'
effect, the latter is apparent for certain events in the two-train experiment.
The importance of relativistic kinematics --embodied for photons in Einstein's
second postulate-- for the correct interpretation of the experiments is pointed
out and demonstrated by detailed calculation of a related example.


title:
Rayleigh-Taylor turbulence is nothing like Kolmogorov turbulence in the
  self similar regime

abstract:
  An increasing number of numerical simulations and experiments describing the
turbulent spectrum of Rayleigh-Taylor (RT) mixing layers came to light over the
past few years. Results reported in recent studies allow to rule out a
turbulence {\it \`a la Kolmogorov} as a mechanism acting on a self similar RT
turbulent mixing layer. A different mechanism is presented, which complies with
both numerical and experimental results and relates RT flow to other buoyant
flows.


title: Singular Modes of the Electromagnetic Field

abstract:
  We show that the mode corresponding to the point of essential spectrum of the
electromagnetic scattering operator is a vector-valued distribution
representing the square root of the three-dimensional Dirac's delta function.
An explicit expression for this singular mode in terms of the Weyl sequence is
provided and analyzed. An essential resonance thus leads to a perfect
localization (confinement) of the electromagnetic field, which in practice,
however, may result in complete absorption.


title: On the Mass of a Universe with a Quantum String-Like Beginning

abstract:
  In this paper the mass of a universe, which began as a gravitationally
closed, maximally spinning, Planck density quantum string is derived. A
universe beginning in such an initial state has been called a Super Spin Model
universe. The total mass, M, of the Super Spin Model universe is shown to be a
function of only four fundamental parameters \hbar, c, G, e, such that: M = \pi
2(\hbar c/G)1/2exp(\hbar c/e2). The present paper primarily consists of a brief
derivation of the above equation and a short synopsis of the Super Spin Model.
  Keywords: Planck, primaton, geon, Kerr, string, cosmology, super spin model,
unification, gravitation, rotating universe, non-stationary, axi-symmetric,
space-time, event horizon.


title:
Exact Kohn-Sham versus Hartree-Fock in momentum-space: examples of
  two-fermion systems

abstract:
  The question of how density functional theory (DFT) compares with
Hartree-Fock (HF) for the computation of momentum-space properties is addressed
in relation to systems for which (near) exact Kohn-Sham (KS) and HF
one-electron matrices are known. This makes it possible to objectively compare
HF and exact KS and hence to assess the potential of DFT for momentum space
studies. The systems considered are the Moshinsky atom, the Hooke's atom and
light two-electron ions, for which expressions for correlated density-matrices
or momentum densities have been derived in closed-form. The results obtained
show that it is necessary to make a distinction between true and approximate
DFT.


title:
Closed-form expressions for correlated density matrices: application to
  dispersive interactions and example of (He)2

abstract:
  Empirically correlated density matrices of N-electron systems are
investigated. Exact closed-form expressions are derived for the one- and
two-electron reduced density matrices from a general pairwise correlated wave
function. Approximate expressions are proposed which reflect dispersive
interactions between closed-shell centro-symmetric subsystems. Said expressions
clearly illustrate the consequences of second-order correlation effects on the
reduced density matrices. Application is made to a simple example: the (He)2
system. Reduced density matrices are explicitly calculated, correct to second
order in correlation, and compared with approximations of independent electrons
and independent electron pairs. The models proposed allow for variational
calculations of interaction energies and equilibrium distance as well as a
clear interpretation of dispersive effects on electron distributions. Both
exchange and second order correlation effects are shown to play a critical role
on the quality of the results.


title:
Field Emission in CEBAF's Superconducting RF Cavities and Implications
  for Future Accelerators

abstract:
  Field emission is one of the key issues in superconducting RF for particle
accelerators. When present, it limits operating gradient directly or via
induced heat load at 2K. In order to minimize particulate contamination of and
thus field emission in the CEBAF SRF cavities during assembly, a cold ceramic
RF window was placed very close to the accelerating cavity proper. As an
unintended consequence of this, the window is charged by field-emitted
electrons, making it possible to monitor and model field emission in the CEBAF
cavities since in-tunnel operation began. From January 30, 1995, through
February 10, 2003, there were 64 instances of spontaneous onset or change in
cavity field emission with a drop in usable gradient averaging 1.4 (sigma 0.8)
MV/m at each event. Fractional loss averaged 0.18 (sigma 0.12) of pre-event
gradient. This event count corresponds to 2.4 events per century per cavity, or
8 per year in CEBAF. It is hypothesized that changes in field emission are due
to adsorbed gas accumulation. The possible implications of this and other
observations for the International Linear Collider (ILC) and other future
accelerators will be discussed.


title:
Fourier relationship between angular position and optical orbital
  angular momentum

abstract:
  We demonstrate the Fourier relationship between angular position and angular
momentum for a light mode. In particular we measure the distribution of orbital
angular momentum states of light that has passed through an aperture and verify
that the orbital angular momentum distribution is given by the complex
Fourier-transform of the aperture function. We use spatial light modulators,
configured as diffractive optical components, to define the initial orbital
angular momentum state of the beam, set the defining aperture, and measure the
angular momentum spread of the resulting beam. These measurements clearly
confirm the Fourier relationship between angular momentum and angular position,
even at light intensities corresponding to the single photon level.


title:
Influences of tongue biomechanics on speech movements during the
  production of velar stop consonants: a modeling study

abstract:
  This study explores the following hypothesis: forward looping movements of
the tongue that are observed in VCV sequences are due partly to the anatomical
arrangement of the tongue muscles and how they are used to produce a velar
closure. The study uses an anatomically based 2D biomechanical tongue model.
Tissue elastic properties are accounted for in finite-element modeling, and
movement is controlled by constant-rate control parameter shifts. Tongue
raising and lowering movements are produced by the model with the combined
actions of the genioglossus, styloglossus and hyoglossus. Simulations of V1CV2
movements were made, where C is a velar consonant and V is [a], [i] or [u]. If
V1 is one of the vowels [a] and [u], the resulting trajectories describe
movements that begin to loop forward before consonant closure and continue to
slide along the palate during the closure. This prediction is in agreement with
classical data published in the literature. If V1 is vowel [i], we observe a
small backward movement. This is also in agreement with some measurements on
human speakers, but it is also in contradiction with the original data
published by Houde (1967). These observations support the idea that the
biomechanical properties of the tongue could be the main factor responsible for
the forward loops when V1 is a back vowel. In the left [i] context, it seems
that additional factors have to be taken into considerations, in order to
explain the observations made on some speakers


title:
Orbital and Maxillofacial Computer Aided Surgery: Patient-Specific
  Finite Element Models To Predict Surgical Outcomes

abstract:
  This paper addresses an important issue raised for the clinical relevance of
Computer-Assisted Surgical applications, namely the methodology used to
automatically build patient-specific Finite Element (FE) models of anatomical
structures. From this perspective, a method is proposed, based on a technique
called the Mesh-Matching method, followed by a process that corrects mesh
irregularities. The Mesh-Matching algorithm generates patient-specific volume
meshes from an existing generic model. The mesh regularization process is based
on the Jacobian matrix transform related to the FE reference element and the
current element. This method for generating patient-specific FE models is first
applied to Computer-Assisted maxillofacial surgery, and more precisely to the
FE elastic modelling of patient facial soft tissues. For each patient, the
planned bone osteotomies (mandible, maxilla, chin) are used as boundary
conditions to deform the FE face model, in order to predict the aesthetic
outcome of the surgery. Seven FE patient-specific models were successfully
generated by our method. For one patient, the prediction of the FE model is
qualitatively compared with the patient's post-operative appearance, measured
from a Computer Tomography scan. Then, our methodology is applied to
Computer-Assisted orbital surgery. It is, therefore, evaluated for the
generation of eleven patient-specific FE poroelastic models of the orbital soft
tissues. These models are used to predict the consequences of the surgical
decompression of the orbit. More precisely, an average law is extrapolated from
the simulations carried out for each patient model. This law links the size of
the osteotomy (i.e. the surgical gesture) and the backward displacement of the
eyeball (the consequence of the surgical gesture).


title: Prediction of tissue decompression in orbital surgery

abstract:
  Objective: A method to predict the relationships between decompressed volume
of orbital soft tissues, backward displacement of globe after osteotomy, and
force exerted by the surgeon, was proposed to improve surgery planning in
exophthalmia reduction. Design: A geometric model and a poroelastic finite
element model were developed, based on Computed Tomography scan data.
Background: The exophthalmia is characterised by a protrusion of the eyeball.
Surgery consists in an osteotomy of the orbit walls to decompress the orbital
content. A few clinical observations ruling on an almost linear relationship
between globe backward displacement and tissue decompressed volume are
described in the literature. Methods: Fast prediction of decompressed volume is
derived from the geometric model: a sphere in interaction with a cone. Besides,
a poroelastic Finite Element model involving morphology, material properties of
orbital components and surgical gesture was implemented. Results: The geometric
model provided a better decompression volume estimation than the Finite Element
model. Besides, the Finite Element model permitted to quantify the backward
displacement, the surgical gesture and the stiffness of the orbital content.
Conclusions: The preliminary results obtained for one patient, in accordance
with the clinical literature, were relatively satisfying. An efficient aid for
location and size of osteotomies was derived and seemed to be able to help in
the surgery planning. Relevance: To our knowledge, this paper concerns the
first biomechanical study of exophthalmia reduction. The approach permitted to
improve the treatment of orbitopathy and can be used in a clinical setting.


title: Biomechanical models to simulate consequences of maxillofacial surgery

abstract:
  This paper presents the biomechanical finite element models that have been
developed in the framework of the computer-assisted maxillofacial surgery.
After a brief overview of the continuous elastic modelling method, two models
are introduced and their use for computer-assisted applications discussed. The
first model deals with orthognathic surgery and aims at predicting the facial
consequences of maxillary and mandibular osteotomies. For this, a generic
three-dimensional model of the face is automatically adapted to the morphology
of the patient by the mean of elastic registration. Qualitative simulations of
the consequences of an osteotomy of the mandible can thus be provided. The
second model addresses the Sleep Apnoea Syndrome. Its aim is to develop a
complete modelling of the interaction between airflow and upper airways walls
during respiration. Dynamical simulations of the interaction during a
respiratory cycle are computed and compared with observed phenomena.


title:
Computer-aided hepatic tumour ablation : requirements and preliminary
  results

abstract:
  Surgical resection of hepatic tumours is not always possible, since it
depends on different factors, among which their location inside the liver
functional segments. Alternative techniques consist in local use of chemical or
physical agents to destroy the tumour. Radio frequency and cryosurgical
ablations are examples of such alternative techniques that may be performed
percutaneously. This requires a precise localisation of the tumour placement
during ablation. Computer-assisted surgery tools may be used in conjunction
with these new ablation techniques to improve the therapeutic efficiency,
whilst they benefit from minimal invasiveness. This paper introduces the
principles of a system for computer-assisted hepatic tumour ablation and
describes preliminary experiments focusing on data registration evaluation. To
keep close to conventional protocols, we consider registration of pre-operative
CT or MRI data to intra-operative echographic data.


title: A 3D dynamical biomechanical tongue model to study speech motor control

abstract:
  A 3D biomechanical dynamical model of human tongue is presented, that is
elaborated in the aim to test hypotheses about speech motor control. Tissue
elastic properties are accounted for in Finite Element Modeling (FEM). The FEM
mesh was designed in order to facilitate the implementation of muscle
arrangement within the tongue. Therefore, its structure was determined on the
basis of accurate anatomical data about the tongue. Mechanically, the
hypothesis of hyperelasticity was adopted with the Mooney-Rivlin formulation of
the strain energy function. Muscles are modeled as general force generators
that act on anatomically specified sets of nodes of the FEM structure. The 8
muscles that are known to be largely involved in the production of basic speech
movements are modeled. The model and the solving of the Lagrangian equations of
movement are implemented using the ANSYSTM software. Simulations of the
influence of muscle activations onto the tongue shape are presented and
analyzed.


title:
A simulator for maxillo-facial surgery integrating cephalometry and
  orthodontia

abstract:
  Objectives : This paper presents a new simulator for maxillo-facial surgery,
that gathers the dental and the maxillo-facial analyses together into a single
computer-assisted procedure. The idea is first to propose a repositioning of
the maxilla, via the introduction of a 3D cephalometry, applied to a 3D virtual
model of the patient's skull. Then, orthodontic data are integrated into this
model, thanks to optical measurements of teeth plaster casts. Materials and
Methods : The feasibility of the maxillo-facial demonstrator was first
evaluated on a dry skull. To simulate malformations (and thus to simulate a
"real" patient), the skull was modified and manually cut by the surgeon, in
order to generate a given maxillo-facial malformation (with asymmetries in the
sagittal, frontal and axial planes). Results : The validation of our simulator
consisted in evaluating its ability to propose a bone repositioning diagnosis
that will put the skull as it was in its original configuration. A first
qualitative validation is provided in this paper, with a 1.5-mm error in the
repositioning diagnosis. Conclusions : These results mainly validate the
concept of a maxillo-facial numerical simulator that integrates 3D cephalometry
and guarantees a correct dental occlusion.


title:
Diffuse light scattering dynamics under conditions of
  electromagnetically induced transparency

abstract:
  We show that, under conditions of electromagnetically induced transparency
(EIT), a significant portion of the incident probe pulse can be transferred
into Rayleigh and Raman scattering channels. The light scattered into the
Rayleigh channel emerges from the sample with an EIT time delay. We show that a
proper description of the probe light propagation in the sample should include,
in the diffusion dynamics, a spin polariton generated by the two-photon EIT
process. The results have important implications for studies of weak light
localization, and for manipulation of single and few photon states in ultracold
atomic gases.


title: Physics Magic

abstract:
  The purpose of this paper is to show the magic of physics by showing the
physics of magic. What usually makes magic tricks interesting is that something
unexpected occurs. Similarly, demonstrations are interesting inasmuch as they
produce something unexpected. Since expectations are linked to preconceptions,
a demonstration making use of a flaw in a preconception will result in
something unexpected. Given the numerous misconceptions in physics, many
demonstrations can be dressed up as magic tricks. The first objective of this
paper is to share with other physics teachers the excitement of creating and
using magical classroom demonstrations. The second objective is to provide
interested instructors with practical means to convert a classical
demonstration into a magic trick. To illustrate the procedure, two classical
demonstrations will be re-presented as the magic tricks we have presented in
our courses. The final goal is to use current ideas in educational psychology
to explain why using magic has worked so well in our courses in providing
students with a new impetus to learn physics. This description is not meant to
be formal, but proposes a theoretical model that fits our classroom
observations.


title: Kuzmin-Osledets Formulations of Compressible Euler Equations

abstract:
  Kuzmin-Oseledets formulations of compressible Euler equations case are
considered. Exact results and physical interpretations are given. One such
exact result for the compressible barotropic case is the potential helicity
Lagrange invariant. In recognition of the fundamental physical implications of
this Lagrange invariant clarified here, this invariant is shown to hold for
compressible non-barotropic cases as well upon using a stronger gauge
condition. Symmetry restoration taking place at the Lagrangian level in the
Kuzmin-Oseledets formulation is pointed out. The Kuzmin-Oseledets formulation
in the compressible barotropic case is shown to admit an exact solution that
physically describes a density wave on a steady irrotational flow with the
Kuzmin-Oseledets velocity q growing monotonically with it and hence specifying
some information about the fluid impulse that is needed to set up the flow in
question.


title: Julian Schwinger (1918-1994)

abstract:
  Julian Schwinger's influence on Twentieth Century science is profound and
pervasive. Of course, he is most famous for his renormalization theory of
quantum electrodynamics, for which he shared the Nobel Prize with Richard
Feynman and Sin-itiro Tomonaga. But although this triumph was undoubtedly his
most heroic accomplishment, his legacy lives on chiefly through subtle and
elegant work in classical electrodynamics, quantum variational principles,
proper-time methods, quantum anomalies, dynamical mass generation, partial
symmetry, and more. Starting as just a boy, he rapidly became the pre-eminent
nuclear physicist in the late 1930s, led the theoretical development of radar
technology at MIT during World War II, and then, soon after the war, conquered
quantum electrodynamics, and became the leading quantum field theorist for two
decades, before taking a more iconoclastic route during his last quarter
century.


title: Spectral Emission of Moving Atom

abstract:
  A renewed analysis of the H.E. Ives and G.R. Stilwell's experiment on moving
hydrogen canal rays (J. Opt. Soc. Am., 1938, v.28, 215) concludes that the
spectral emission of a moving atom exhibits always a redshift which informs not
the direction of the atom's motion. The conclusion is also evident from a
simple energy relation: atomic spectral radiation is emitted as an orbiting
electron consumes a portion of its internal energy on transiting to a
lower-energy state which however has in a moving atom an additional energy
gain; this results in a redshift in the emission frequency. Based on auxiliary
experimental information and a scheme for de Broglie particle formation, we
give a vigorous elucidation of the mechanism for deceleration radiation of
atomic electron; the corresponding prediction of the redshift is in complete
agreement with the Ives and Stilwell's experimental formula.


title:
The Absolutism of Space and Time with Variable Scalars and Gravitational
  Theory as well as Cosmology Established in Flat Reference Frame (1)

abstract:
  The Einstein theories of space-time and gravity as well the stander cosmology
are reconstructed thoroughly in this paper based on flat reference frame. The
rational parts of the Einstein theories are reserved while the irrational parts
including space-time paradoxes and singularities and so on are eliminated
completely. A more rational the theory of space-time, gravitation and cosmology
is established. By transforming the geodesic equation described by the
Schwarzschild solution of the Einsteins equation of gravitational field into
flat reference frame for of gravitational field, it is provdescription, the
revised formulas of the Newtonian gravitation is obtained. Based on the
formulas, all experiments which support general relativity can also be
explained well, but the theory has no any space-time singularity and other
strange characters which exist in general relativity. It is pointed that there
exists logical difficulties to use the equivalent principle to explain spectrum
gravitational redshift actually. The new formula of gravitational redshift and
the revised Doppler formula of redshift when light source moves in
gravitational field are deduced. Based on the Schwarzschild solution of the
Einstein equation field, it is proved that the speed of light would change and
the isotropy of light speed would be violated in gravitational field with
spherical symmetry. It is suggested to use the method of the Michelson Morley
interference to verify the change of light speed and the violation of isotropy
in the gravitational field of the earth. This experiment can be considered as a
new verification for general relativity in the weak gravitational field with
spherical symmetry. The theory may also be used to explain so-called the
Pioneer Anomaly which the Einstein theory of gravitation can not do.


title: Boundary-integral method for poloidal axisymmetric AC magnetic fields

abstract:
  This paper presents a boundary-integral equation (BIE) method for the
calculation of poloidal axisymmetric magnetic fields applicable in a wide range
of ac frequencies. The method is based on the vector potential formulation and
it uses the Green's functions of Laplace and Helmholtz equations for the
exterior and interior of conductors, respectively. The work is particularly
focused on a calculation of axisymmetric Green's function for the Helmholtz
equation which is both simpler and more accurate compared to previous
approaches. Three different approaches are used for calculation of the Green's
function depending on the parameter range. For low and high dimensionless ac
frequencies we use a power series expansion in terms of elliptical integrals
and an asymptotic series in terms of modified Bessel functions of second kind,
respectively. For the intermediate frequency range, Gauss-Chebyshev-Lobatto
quadratures are used. The method is verified by comparing with the analytical
solution for a sphere in a uniform external ac field. The application of the
method is demonstrated for a composite model inductor containing an external
secondary circuit.


title:
Chaotic synchronization in coupled spatially extended beam-plasma
  systems

abstract:
  The appearance of the chaotic synchronization regimes has been discovered for
the coupled spatially extended beam-plasma Pierce systems. The coupling was
introduced only on the right bound of each subsystem. It has been shown that
with coupling increase the spatially extended beam-plasma systems show the
transition from asynchronous behavior to the phase synchronization and then to
the complete synchronization regime. For the consideration of the chaotic
synchronization we used the concept of time scale synchronization described in
work [Chaos, 14, 3 (2004) 603-610] and based on the introduction of the
continuous set of phases of chaotic signal. In case of unidirectional coupling
the generalized synchronization regime has been observed in the spatially
extended beam-plasma systems. The generalized synchronization appearance
mechanism has been analyzed by means of the offered modified system approach
[Phys. Rev. E, 71, 6 (2005) 067201].


title:
On electromagnetics of an isotropic chiral medium moving at constant
  velocity

abstract:
  A medium which is an isotropic chiral medium from the perspective of a
co-moving observer is a Faraday chiral medium (FCM) from the perspective of a
non-co-moving observer. The Tellegen constitutive relations for this FCM are
established. By an extension of the Beltrami field concept, these constitutive
relations are exploited to show that planewave propagation is characterized by
four generally independent wavenumbers. This FCM can support negative phase
velocity at certain translational velocities and with certain wavevectors, even
though the corresponding isotropic chiral medium does not. The constitutive
relations and Beltrami--like fields are also used to develop a convenient
spectral representation of the dyadic Green functions for the FCM.


title: The Cascade of Circulations in Fluid Turbulence

abstract:
  Kelvin's Theorem on conservation of circulations is an essential ingredient
of G. I. Taylor's theory of turbulent energy dissipation by the process of
vortex-line stretching. In previous work, we have proposed a nonlinear
mechanism for the breakdown of Kelvin's Theorem in ideal turbulence at infinite
Reynolds number. We develop here a detailed physical theory of this ``cascade
of circulations''. Our analysis is based upon an effective equation for
large-scale ``coarse-grained'' velocity, which contains a turbulent-induced
``vortex-force'' that can violate Kelvin's Theorem. We show that singularities
of sufficient strength, which are observed to exist in turbulent flow, can lead
to non-vanishing dissipation of circulation for an arbitrarily small filtering
length in the effective equations. This result is an analogue for circulation
of Onsager's theorem on energy dissipation for singular Euler solutions. The
physical mechanism of the breakdown of Kelvin's Theorem is diffusion of lines
of large-scale vorticity out of the advected loop. This phenomenon can be
viewed as a classical analogue of the Josephson-Anderson phase-slip phenomenon
in superfluids due to quantized vortex lines. We show that the circulation
cascade is local in scale and use this locality to develop concrete expressions
for the turbulent vortex-force by a multi-scale gradient-expansion. We discuss
implications for Taylor's theory of turbulent dissipation and we point out some
related cascade phenomena, in particular for magnetic-flux in
magnetohydrodynamic (MHD) turbulence.


title: Lattice-supported surface solitons in nonlocal nonlinear media

abstract:
  We reveal that lattice interfaces imprinted in nonlocal nonlinear media
support surface solitons that do not exist in other similar settings, including
interfaces of local and nonlocal uniform materials. We show the impact of
nonlocality on the domains of existence and stability of the surface solitons,
focusing on new types of dipole solitons residing partially inside the optical
lattice. We find that such solitons feature strongly asymmetric shapes and that
they are stable in large parts of their existence domain.


title:
Liquidity and the multiscaling properties of the volume traded on the
  stock market

abstract:
  We investigate the correlation properties of transaction data from the New
York Stock Exchange. The trading activity f(t) of each stock displays a
crossover from weaker to stronger correlations at time scales 60-390 minutes.
In both regimes, the Hurst exponent H depends logarithmically on the liquidity
of the stock, measured by the mean traded value per minute. All multiscaling
exponents tau(q) display a similar liquidity dependence, which clearly
indicates the lack of a universal form assumed by other studies. The origin of
this behavior is both the long memory in the frequency and the size of
consecutive transactions.


title: Thick GEM-like (THGEM) detectors and their possible applications

abstract:
  Thick GEM-like (THGEM) electrodes are robust, high gain gaseous electron
multipliers, economically-manufactured by standard drilling and etching of thin
printed circuit board or other materials. Their operation and structure are
similar to that of standard GEMs but with 5 to 20-fold expanded dimensions. Due
to the larger hole dimensions they provide up to 10^5 and 10^7 charge
multiplication, in a single- and in two-electrode cascade, respectively. The
signal rise time is of a few ns and the counting-rate capability approaches 10
MHz/mm^2 at 10^4 gains. Sub-mm localization precision was demonstrated with a
simple, delay-line based 2D readout scheme. These multipliers may be produced
in a variety of shapes and sizes and can operate in many gases. They may
replace the standard GEMs in many applications requiring very large area,
robust, flat, thin detectors, with good timing and counting-rate properties and
modest localization. The properties of these multipliers are presented in short
and possible applications are discussed.


title:
Extension of Interesting Question I raised about 'Momentum' K of a
  Geodestic g at the J.A. Wheeler Astro physics School with possible numerical
  modeling of Deformations of Light Cones

abstract:
  I present the background of a question I asked Richard Matzner at the John
Wheeler astrophysics school in Erice, at the Majorana institute of scientific
culture during May 31st -June 8th. with an extension of the question to the
issue of possible light cone deformation. This possibly has relevance to the
stability of numerical algorithms used in modeling gravitational waves from
Schwartzshield metric solutions of black holes and similar objects. This
involves the so called momentum K of a geodestic g, with its re casting in a
Kerr shield co ordinates of the Schwartzshield metric. for two black holes
which have anti parallel spins but which exhibit spin coupling between them.


title: Analysis of aggregated tick returns: evidence for anomalous diffusion

abstract:
  In order to investigate the origin of large price fluctuations, we analyze
stock price changes of ten frequently traded NASDAQ stocks in the year 2002.
Though the influence of the trading frequency on the aggregate return in a
certain time interval is important, it cannot alone explain the heavy tailed
distribution of stock price changes. For this reason, we analyze intervals with
a fixed number of trades in order to eliminate the influence of the trading
frequency and investigate the relevance of other factors for the aggregate
return. We show that in tick time the price follows a discrete diffusion
process with a variable step width while the difference between the number of
steps in positive and negative direction in an interval is Gaussian
distributed. The step width is given by the return due to a single trade and is
long-term correlated in tick time. Hence, its mean value can well characterize
an interval of many trades and turns out to be an important determinant for
large aggregate returns. We also present a statistical model reproducing the
cumulative distribution of aggregate returns. For an accurate agreement with
the empirical distribution, we also take into account asymmetries of the step
widths in different directions together with crosscorrelations between these
asymmetries and the mean step width as well as the signs of the steps.


title:
Manipulation of ultracold atoms in dressed adiabatic radio frequency
  potentials

abstract:
  We explore properties of atoms whose magnetic hyperfine sub-levels are
coupled by an external magnetic radio frequency (rf) field. We perform a
thorough theoretical analysis of this driven system and present a number of
systematic approximations which eventually give rise to dressed adiabatic radio
frequency potentials. The predictions of this analytical investigation are
compared to numerically exact results obtained by a wave packet propagation. We
outline the versatility and flexibility of this new class of potentials and
demonstrate their potential use to build atom optical elements such as
double-wells, interferometers and ringtraps. Moreover, we perform simulations
of interference experiments carried out in rf induced double-well potentials.
We discuss how the nature of the atom-field coupling mechanism gives rise to a
decrease of the interference contrast.


title: Transport on Complex Networks: Flow, Jamming and Optimization

abstract:
  Many transport processes on networks depend crucially on the underlying
network geometry, although the exact relationship between the structure of the
network and the properties of transport processes remain elusive. In this paper
we address this question by using numerical models in which both structure and
dynamics are controlled systematically. We consider the traffic of information
packets that include driving, searching and queuing. We present the results of
extensive simulations on two classes of networks; a correlated cyclic
scale-free network and an uncorrelated homogeneous weakly clustered network. By
measuring different dynamical variables in the free flow regime we show how the
global statistical properties of the transport are related to the temporal
fluctuations at individual nodes (the traffic noise) and the links (the traffic
flow). We then demonstrate that these two network classes appear as
representative topologies for optimal traffic flow in the regimes of low
density and high density traffic, respectively. We also determine statistical
indicators of the pre-jamming regime on different network geometries and
discuss the role of queuing and dynamical betweenness for the traffic
congestion. The transition to the jammed traffic regime at a critical posting
rate on different network topologies is studied as a phase transition with an
appropriate order parameter. We also address several open theoretical problems
related to the network dynamics.


title: A rigorous definition of mass in special relativity

abstract:
  The axiomatic definition of mass in classical mechanics, outlined by Mach in
the second half of 19th century and improved by several authors, is simplified
and extended to the theory of special relativity. According to the extended
definition presented here, the mass of a relativistic particle is independent
of its velocity and coincides with the rest mass, i.e., with the mass defined
in classical mechanics. Then, force is defined as the product of mass and
acceleration, both in the classical and in the relativistic framework.


title: Temperature dependent refractive index of silicon and germanium

abstract:
  Silicon and germanium are perhaps the two most well-understood semiconductor
materials in the context of solid state device technologies and more recently
micromachining and nanotechnology. Meanwhile, these two materials are also
important in the field of infrared lens design. Optical instruments designed
for the wavelength range where these two materials are transmissive achieve
best performance when cooled to cryogenic temperatures to enhance signal from
the scene over instrument background radiation. In order to enable high quality
lens designs using silicon and germanium at cryogenic temperatures, we have
measured the absolute refractive index of multiple prisms of these two
materials using the Cryogenic, High-Accuracy Refraction Measuring System
(CHARMS) at NASA Goddard Space Flight Center, as a function of both wavelength
and temperature. For silicon, we report absolute refractive index and
thermo-optic coefficient (dn/dT) at temperatures ranging from 20 to 300 K at
wavelengths from 1.1 to 5.6 microns, while for germanium, we cover temperatures
ranging from 20 to 300 K and wavelengths from 1.9 to 5.5 microns. We compare
our measurements with others in the literature and provide
temperature-dependent Sellmeier coefficients based on our data to allow
accurate interpolation of index to other wavelengths and temperatures. Citing
the wide variety of values for the refractive indices of these two materials
found in the literature, we reiterate the importance of measuring the
refractive index of a sample from the same batch of raw material from which
final optical components are cut when absolute accuracy greater than +/-5 x
10^-3 is desired.


title:
Cooperating or Fighting with Control Noise in the Optimal Manipulation
  of Quantum Dynamics

abstract:
  This paper investigates the impact of control field noise on the optimal
manipulation of quantum dynamics. Simulations are performed on several
multilevel quantum systems with the goal of population transfer in the presence
of significant control noise. The noise enters as run-to-run variations in the
control amplitude and phase with the observation being an ensemble average over
many runs as is commonly done in the laboratory. A genetic algorithm with an
improved elitism operator is used to find the optimal field that either fights
against or cooperates with control field noise. When seeking a high control
yield it is possible to find fields that successfully fight with the noise
while attaining good quality stable results. When seeking modest control
yields, fields can be found which are optimally shaped to cooperate with the
noise and thereby drive the dynamics more efficiently. In general, noise
reduces the coherence of the dynamics, but the results indicate that population
transfer objectives can be met by appropriately either fighting or cooperating
with noise, even when it is intense.


title:
Two-dimensional flow of foam around a circular obstacle: local
  measurements of elasticity, plasticity and flow

abstract:
  We investigate the two-dimensional flow of a liquid foam around circular
obstacles by measuring all the local fields necessary to describe this flow:
velocity, pressure, bubble deformations and rearrangements. We show how our
experimental setup, a quasi-2D "liquid pool" system, is adapted to the
determination of these fields: the velocity and bubble deformations are easy to
measure from 2D movies, and the pressure can be measured by exploiting a
specific feature of this system, a 2D effective compressibility. To describe
accurately bubble rearrangements, we propose a new, tensorial descriptor. All
these quantities are evaluated via an averaging procedure that we justify
showing that the fluctuations of the fields are essentially random. The flow is
extensively studied in a reference experimental case; the velocity presents an
overshoot in the wake of the obstacle, the pressure is maximum at the leading
side and minimal at the trailing side. The study of the elastic deformations
and of the velocity gradients shows that the transition between plug flow and
yielded regions is smooth. Our tensorial description of T1s highlight their
correlation both with the bubble deformations and the velocity gradients. A
salient feature of the flow, notably on the velocity and T1 repartition, is a
marked asymmetry upstream/downstream, signature of the elastic behaviour of the
foam. We show that the results do not change qualitatively when various control
parameters vary, identifying a robust quasistatic regime. These results are
discussed in the frame of the actual foam rheology literature, and we argue
that they constitute a severe test for existing rheological models, since they
capture both the elastic, plastic and fluid behaviour of the foam.


title: The Lorentz-Einstein length contraction is a real effect

abstract:
  An elementary thought experiment is used to show that once the time
dilatation effect is established, there is no way to escape a dual length
contraction.


title:
The Lorentz Transformation for Photons in Dispersive Media and in
  Gravitational Fields

abstract:
  It is pointed out that the traditional explanation for the observation of a
non-zero energy h nu for light in free space does not apply for the analogous
situation in dispersive media. Because the speed of light u is no longer equal
to c in this case, the key quantity, gamma = (1-u2/c2)-0.5, is finite as a
result. Since the rest energy of photons is believed to always be equal to
zero, multiplying it with gamma in analogy to the usual procedure employed in
the special theory of relativity (STR) does not produce a nonzero result for
photons in dispersive media. The experimental evidence of the Fizeau light-drag
and Cerenkov radiation phenomena indicate that the Lorentz transformation in
free space is nonetheless valid for light in dispersive media. Instead, the
energy and momentum of photons in transparent media can be obtained from
observations of the frequency, wavelength and index of refraction of the light.
A modification of the Lorentz transformation in which the observed speed of
light does appear explicitly is required, however, in order to accurately
predict the results of measurements made when the observer is at a different
gravitational potential than the object.


title:
Experimental investigation of spinning massive body influence on fine
  structure of distribution functions of alpha-decay rate fluctuations

abstract:
  The present investigation is dedicated to study of physical basis of
macroscopic fluctuations effect. In particular experimental investigation of
possible influence of rapidly spinning massive body on distribution function of
the alpha-decay rate fluctuations was carried out. Possible anisotropy of such
influence was tested. The paper also contains fundamentals of the macroscopic
fluctuations effect, method of experimental data processing and short review of
phenomenology collected during more than fifty-years history of the macroscopic
fluctuation effect investigations.


title: Nano plasmon polariton modes of a wedge cross section metal waveguide

abstract:
  Optical plasmon-polariton modes confined in both transverse dimensions to
significantly less than a wavelength are exhibited in open waveguides
structured as sharp metal wedges. The analysis reveals two distinctive modes
corresponding to a localized mode on the wedge point and surface mode
propagation on the abruptly bent interface. These predictions are accompanied
by unique field distributions and dispersion characteristics.


title:
Spin-dependent localized Hartree-Fock density-functional approach for
  the accurate treatment of inner-shell excitation of close-shell atoms

abstract:
  We present a spin-dependent localized Hartree-Fock (SLHF) density-functional
approach for the treatment of the inner-shell excited-state calculation of
atomic systems. In this approach, the electron spin-orbitals in an electronic
configuration are obtained first by solving Kohn-Sham (KS) equation with SLHF
exchange potential. Then a single-Slater-determinant energy of the electronic
configuration is calculated by using these electron spin-orbitals. Finally, a
multiplet energy of an inner-shell excited state is evaluated from the
single-Slater-determinant energies of the electronic configurations involved in
terms of Slater's diagonal sum rule. This procedure has been used to calculate
the total and excitation energies of inner-shell excited states of close-shell
atomic systems: Be, B^+, Ne, and Mg. The correlation effect is taken into
account by incorporating the correlation potentials and energy functionals of
Perdew and Wang's (PW) or Lee, Yang, and Parr's (LYP) into calculation. The
calculated results with the PW and LYP energy functionals are in overall good
agreement with each other and also with available experimental and other ab
initio theoretical data. In addition, we present some new results for highly
excited inner-shell states.


title: Trouton-Noble paradox revisited

abstract:
  An apparent paradox is obtained in all previous treatments of the
Trouton-Noble experiment; there is a three-dimensional torque in an inertial
frame S in which a thin parallel-plate capacitor is moving, but there is no 3D
torque in S', the rest frame of the capacitor. In this paper instead of using
3D quantities and their ``apparent'' transformations we deal with 4D geometric
quantities their Lorentz transformations and equations with them. We introduce
a new decomposition of the torque N (bivector) into 1-vectors N_{s} and N_{t}.
It is shown that in the frame of ``fiducial'' observers, in which the observers
who measure N_{s} and N_{t} are at rest, and in the standard basis, only the
spatial components N_{s}^{i} and N_{t}^{i} remain, which can be associated with
components of two 3D torques. In such treatment with 4D geometric quantities
the mentioned paradox does not appear. The presented explanation is in a
complete agreement with the principle of relativity and with the Trouton-Noble
experiment without the introduction of any additional torque.


title:
A statistical method for luminosity monitoring in high energy collider
  experiments

abstract:
  A statistical method which uses a combination of two subdetectors to monitor
the luminosity in high energy interactions is presented. To illustrate its
performance, this method was applied to random triggered minimum bias data
collected in the commissioning period of the HERA-B experiment in spring 2000.
It is found that luminosity estimates with an intrinsic systematic error of 3%
can be obtained.


title: Geometrical Aspects in Optical Wavepacket Dynamics

abstract:
  We construct a semiclassical theory for propagation of an optical wavepacket
in non-conducting media with periodic structures of dielectric permittivity and
magnetic permeability, i.e., non-conducting photonic crystals. We employ a
quantum-mechanical formalism in order to clarify its link to those of
electronic systems. It involves the geometrical phase, i.e., Berry phase, in a
natural way, and describes an interplay between orbital motion and the internal
rotation. Based on the above theory, we discuss the geometrical aspects of the
optical Hall effect. We also consider a reduction of the theory to a system
without periodic structure and apply it to the transverse shift at an interface
reflection/refraction. For generic incident beams with elliptic polarizations,
an identical result for the transverse shift of each reflected/transmitted beam
is given by the following different approaches; (i) analytic evaluation of
wavepacket dynamics, (ii) total angular momentum (TAM) conservation {\it for
individual photons}, and (iii) numerical simulation of wavepacket dynamics. It
is consistent with a result by classical electrodynamics. This means that the
TAM conservation for individual photons is already taken into account in wave
optics, i.e, classical electrodynamics. Finally, we show an application of our
theory to a two-dimensional photonic crystal, and propose an optimal design for
the enhancement of the optical Hall effect in photonic crystals.


title: Probability and Statistical Inference

abstract:
  These lectures introduce key concepts in probability and statistical
inference at a level suitable for graduate students in particle physics. Our
goal is to paint as vivid a picture as possible of the concepts covered.


title: A revisit to the GNSS-R code range precision

abstract:
  We address the feasibility of a GNSS-R code-altimetry space mission and more
specifically a dominant term of its error budget: the reflected-signal range
precision. This is the RMS error on the reflected-signal delay, as estimated by
waveform retracking. So far, the approach proposed by [Lowe et al., 2002] has
been the state of the art to theoretically evaluate this precision, although
known to rely on strong assumptions (e.g., no speckle noise). In this paper, we
perform a critical review of this model and propose an improvement based on the
Cramer-Rao Bound (CRB) approach. We derive closed-form expressions for both the
direct and reflected signals. The performance predicted by CRB analysis is
about four times worse for typical space mission scenarios. The impact of this
result is discussed in the context of two classes of GNSS-R applications:
mesoscale oceanography and tsunami detection.


title:
Variational multiscale turbulence modelling in a high order spectral
  element method

abstract:
  One of the more promising recent approaches to turbulence modelling is the
Variational Multiscale Large Eddy Simulation (VMS LES) method proposed by
Hughes et al. [Comp. Visual. Sci., vol. 3, pp. 47-59, 2000]. This method avoids
several conceptual issues of traditional filter-based LES by employing a priori
scale partitioning in the discretization of the Navier-Stokes equations.
  Most applications of VMS LES reported to date have been based on hierarchical
bases, in particular global spectral methods, in which scale partitioning is
straightforward. In the present work we describe the implementation of the
methodology in a three-dimensional high-order spectral element method with a
nodal basis. We report results from coarse grid simulations of turbulent
channel flow at different Reynolds numbers to assess the performance of the
model.
  Key words: Large eddy simulation, variational multiscale method, spectral
element method, incompressible flow 1991 MSC: 76F65, 65M60, 65M70 PACS:
47.27.Eq, 02.70.Hm, 02.70.Dh


title:
The total cross-sections for the photoeffect for K-shell bound electrons
  and pair production with the created electron in the ground state for photon
  energies above 1 MeV

abstract:
  Considering the contributions of the main term of the relativistic Coulombian
Green function given by Hostler to the second order of S matrix element and
taking into account only the large components of the Dirac spinor of the ground
state we obtain the imaginary part of the Rayleigh amplitudes in terms of
elementary functions. Thereby simple and high accurate formulae for the total
cross-sections for photoeffect and pair production with the electron created in
the K-shell are obtained \textit{via} the optical theorem.Comparing the
predictions given by our formulae with the full relativistic numerical
calculations of Kissel \textit{et al} [Phys. Rev. A 22, 1970 (1980)] and
Scofield [LLRL, Internal Report,1973], a good agreement is found for photon
energies above the pair production threshold up to 5 MeV for any Z elements. We
present our numerical results for the total photoeffect and pair production
cross-sections, for various photon energies for the K-shell of Ag and Pb.


title:
The total cross-sections for the photoeffect for 2S-subshell bound
  electrons and pair production with the created electron in the 2S subshell
  for photon energies above 1 MeV

abstract:
  Considering the contributions of the main term of the relativistic Coulombian
Green function given by Hostler [J. Math. Phys, 5, 591 (1964)] to the second
order of the S-matrix element and taking into account only the large components
of Dirac spinor of the 2S subshell, we have obtained the imaginary part of the
Rayleigh amplitudes in terms of elementary functions. Thereby, simple and high
accurate formulae for the total cross-sections for photoeffect and pair
production with the electron created in the 2S subshell are obtained via the
optical theorem. Comparing the predictions given by our formulae with the full
relativistic numerical calculations of Kissel et al [Phys. Rev. A 22, 1970
(1980)] and Scofield [LLRL, Internal Report (1973)], a good agreement is found
for low and intermediate Z values if screening effects are taken into account,
for photon energies above the pair production threshold energy. We present our
numerical results for the total photoeffect and pair production cross-sections
for the 2S subshell of Zn and Ag atoms, for various photon energies.


title:
The nonrelativistic limit of the second order S-matrix element for the
  elastic scattering of photons by K-shell bound electrons

abstract:
  In this paper, the right expressions of the fully nonrelativistic K-shell
Rayleigh scattering amplitudes and cross-sections are obtained by using the
Coulomb Green function method. Our analytical result has no spurious poles as
the old nonrelativistic result with retardation [M. Gavrila and A.Costescu
Phys. Rev. A 2, 1752 (1970)] presents. Taking into account the exact expression
of the second order S-matrix element in the case of the elastic scattering of
photons by K-shell bound electrons we obtain its nonrelativistic limit (valid
for photon energies omega up to alpha*Z*m, for intermediate Z), by removing in
a consistent and appropriate way the higher order terms in alpha*Z and omega/m.
We obtain the imaginary part of the Rayleigh amplitudes in terms of elementary
functions. Thereby the exact nonrelativistic total photoeffect cross-section is
obtained via the optical theorem. Comparing the predictions given by our
formulae with the full relativistic numerical calculations of Kissel et al
[Phys. Rev. A 22, 1970 (1980)], and with experimental results, a fairly good
agreement within 10% is found for the angular distribution of Rayleigh
scattering for photon energies up to alpha*Z*m, for intermediate Z, and up to
twice the photoeffect threshold energy for high Z elements. Considering the
right relativistic location for the photoeffect threshold very good predictions
are found below the first resonance, even in its vicinity. We present our
numerical results for Rayleigh angular distribution and the photoeffect total
cross-section, for various photon energies, scattering angles and Z, compared
with other theoretical and experimental results.


title:
Year-ahead Prediction of Hurricane Season Sea Surface Temperature in the
  Tropical Atlantic

abstract:
  One possible method for the year-ahead prediction of hurricane numbers would
be to make a year-ahead prediction of sea surface temperature (SST), and then
to apply relationships that link SST to hurricane numbers. As a first step
towards setting up such a system this article compares three simple statistical
methods for the year-ahead prediction of the relevant SSTs.


title: Alice and Bob Get Away With It: a playlet

abstract:
  Alice and Bob use Aravind's version of a Bell-Kochen-Specker paradox to fend
off awkward questions about what exactly they were doing in Amsterdam last
week.


title:
A simplification of the vorticity equation and an extension of the
  vorticity persistence theorem to three dimensions

abstract:
  A simplified form of the vorticity equation is derived for arbitrary
coordinate systems. The present work unifies and extends the previous findings
that vorticity is conserved in planar Euler flow, while in axisymmetric Euler
rings it is the ratio of the vorticity to the distance from the symmetry axis
that is conserved. The unifying statement is that in any Euler flow, all
components of the vorticity tensor of a streamline coordinate system that are
normal to the streamline direction are conserved along streamlines. This is
true for both two- and three-dimensional flows, whether the flow is
axisymmetric or not, with or without swirl. What remains of the nonlinear
convective terms in the vorticity equation, after the mathematical
simplification, is the Lie derivative of the vorticity tensor with respect to
fluid velocity. A temporal derivative is defined which, when set to zero,
expresses either the continuity or vorticity equation (excluding the viscous
term), depending upon the argument supplied to it.


title:
Muon decays in the Earth's atmosphere, time dilatation and relativity of
  simultaneity

abstract:
  Observation of the decay of muons produced in the Earth's atmosphere by
cosmic ray interactions provides a graphic illustration of the
counter-intuitive space-time predictions of special relativity theory. Muons at
rest in the atmosphere decaying simultaneously are subject to a universal
time-dilatation effect when viewed from a moving frame and so are also observed
to decay simultaneously in all such frames, whereas the decays of muons with
different proper frames show relativity of simultaneity when observed from
different inertial frames.


title: Optical activity in the Drude helix model

abstract:
  An old classical one-particle helix model for optical activity, first
proposed by Drude, is reconsidered here. The quantum Drude model is very
instructive because the optical activity can be calculated analytically without
further approximations apart from the Rosenfeld long wavelength approximation.
While it was generally believed that this model, when treated correctly, is
optically inactive, we show that it leads to optical activity when the motion
of the particle is quantum mechanically treated. We also find that optical
activity arises even in the classical regime at non-zero energy, while for zero
energy the model is inactive, in accordance with previous results. The model is
compared with other one-electron models and it is shown that its predicted
optical activity is qualitatively different from those of other one-electron
systems. The vanishing of optical activity in the classical zero-energy limit
for the Drude model is due to the localization of the particle at the
equilibrium position, whereas in the analogous model of a particle moving
freely on a helix without a definite equilibrium position, optical activity
does not vanish but the spectrum is rescaled. The model under study leads to
interesting predictions about the optical properties of e. g. helicene
derivatives.


title:
Publish or perish: analysis of scientific productivity using maximum
  entropy principle and fluctuation-dissipation theorem

abstract:
  Using data retrieved from the INSPEC database we have quantitatively
discussed a few syndromes of the publish-or-perish phenomenon, including
continuous growth of rate of scientific productivity, and continuously
decreasing percentage of those scientists who stay in science for a long time.
Making use of the maximum entropy principle and fluctuation-dissipation
theorem, we have shown that the observed fat-tailed distributions of the total
number of papers x authored by scientists may result from the density of states
function g(x;\tau) underlying scientific community. Although different
generations of scientists are characterized by different productivity patterns,
the function g(x;\tau) is inherent to researchers of a given seniority \tau,
whereas the publish-or-perish phenomenon is caused only by an external field
\theta influencing researchers.


title: Estimating Surface Sediments Using Multibeam Sonar

abstract:
  We detail acoustic backscatter processing for characterization and mapping of
the ocean bottom.


title:
Year ahead prediction of US landfalling hurricane numbers: the optimal
  combination of long and short baselines for intense hurricanes

abstract:
  In previous work, we have shown how to combine long and short historical
baselines to make predictions of future hurricane numbers. We now ask: how
should such combinations change if we are interested in predicting the future
number of intense hurricanes?


title:
Scintillation index for two Gaussian laser beams with different
  wavelengths in weak atmospheric turbulence

abstract:
  We study propagation of two lowest order Gaussian laser beams with different
wavelengths in weak atmospheric turbulence. Using the Rytov approximation and
assuming a slow detector we calculate the longitudinal and radial components of
the scintillation index for a typical free space laser communication setup. We
find the optimal configuration of the two laser beams with respect to the
longitudinal scintillation index. We show that the value of the longitudinal
scintillation for the optimal two-beam configuration is smaller by more than
50% compared with the value for a single lowest order Gaussian beam with the
same total power. Furthermore, the radial scintillation for the optimal
two-beam system is smaller by 35%-40% compared with the radial scintillation in
the single beam case. Further insight into the reduction of intensity
fluctuations is gained by analyzing the self- and cross-intensity contributions
to the scintillation index.


title: ATF2 Proposal Vol.2

abstract:
  The two major goals for this facility, called ATF2, are : (A) Achievement of
a 37 nm beam size, and (B) control of beam position down to 2 nm level. The
scientific justification for the ATF2 project and its technical design have
been described in Volume 1 of the ATF2 Proposal. We present here Volume 2 of
the ATF2 Proposal, in which we present specifics of the construction plans and
the group organization to execute the research programs at ATF2.


title:
A novel method for unambiguous ion identification in mixed ion beams
  extracted from an EBIT

abstract:
  A novel technique to identify small fluxes of mixed highly charged ion beams
extracted from an Electron Beam Ion Trap (EBIT) is presented and practically
demonstrated. The method exploits projectile charge state dependent potential
emission of electrons as induced by ion impact on a metal surface to separate
ions with identical or very similar mass-to-charge ratio.


title:
Generalized theory for numerical instability of the Gaussian-filtered
  Navier-Stokes equations as a model system for large eddy simulation of
  turbulence

abstract:
  The Gaussian-filtered Navier-Stokes equations are examined theoretically and
a generalized theory of their numerical stability is proposed. Using the exact
expansion series of subfilter-scale stresses or integration by parts, the terms
describing the interaction between the mean and fluctuation portions in a
statistically steady state are theoretically rewritten into a closed form in
terms of the known filtered quantities. This process involves high-order
derivatives with time-independent coefficients. Detailed stability analyses of
the closed formulas are presented for determining whether a filtered system is
numerically stable when finite difference schemes or others are used to solve
it. It is shown that by the Gaussian filtering operation, second and higher
even-order derivatives are derived that always exhibit numerical instability in
a fixed range of directions; hence, if the filter widths are unsuitably large,
the filtered Navier-Stokes equations can in certain cases be unconditionally
unstable even though there is no error in modeling the subfilter-scale stress
terms. As is proved by a simple example, the essence of the present discussion
can be applied to any other smooth filters; that is, such a numerical
instability problem can arise whenever the dependent variables are smoothed out
by a filter.


title: Looking for a time independent Hamiltonian of a dynamical system

abstract:
  In this paper we introduce a method for finding a time independent
Hamiltonian of a given dynamical system by canonoid transformation. We also
find a condition that the system should satisfy to have an equivalent time
independent formulation. We study the example of damped oscillator and give the
new time independent Hamiltonian for it, which has the property of tending to
the standard Hamiltonian of the harmonic oscillator as damping goes to zero.


title:
The measurement of scintillation emission spectra by a coincident photon
  counting technique

abstract:
  In the evaluation of novel scintillators, it is important to ensure that the
spectrum of the light emitted by the scintillator is well matched to the
response of the photomultiplier. In attempting to measure this spectrum using
radioactive sources, it is found that so few photons are emitted per
scintillation event that conventional spectroscopic techniques cannot easily be
used. A simple photon counting technique is presented, using two
photomultipliers operated in coincidence, the one viewing the scintillator
directly, while the other views it through a monochromator. This system allows
the spectrum to be measured without using specially cooled photomultipliers,
intense radioactive sources or particle beams.


title:
Band Edge Effects and Normal Mode Propagation in Waveguide
  Magnetophotonic Crystals

abstract:
  A study of band edge phenomena in ridge waveguide magnetophotonic crystals is
presented. Normal mode analysis is used to examine the near-band edge and Bragg
center-wavelength group velocities and their relation to the polarization.
Large polarization departures from the input are observed in Bragg gratings
patterned by focused-ion-beam milling on liquid-phase-epitaxial (LPE) BiLuIG
films on (111) gadolinium gallium garnet (GGG) substrates. Transfer matrix
analysis of the spectral response in the photonic crystals allows the
determination of the phase of the elliptically polarized normal modes from
measured transmittances and polarization rotation. Unlike non-birefringent
Faraday rotators a non-linear-relation exists between polarization rotation and
the normal mode phase difference. Large phase differences between right- and
left-elliptically polarized normal modes and optical slow-down are found near
the band edges and at the resonant cavity center-wavelength. Standing-wave
photon trapping and optical slow-down are analyzed and compared for these
systems.


title:
Polarization rotation enhancement by high-order waveguide mode coupling
  in magnetophotonic crystals

abstract:
  Inter-modal coupling in photonic bandgap optical channels in magnetic films
is used to leverage the transverse-electric (TE) to transverse-magnetic (TM)
mode conversion due to the Faraday Effect. The underlying mechanism is traced
to the dependence of the grating coupling-constant on the modal refractive
index and the mode profile of the propagating beam, a feature that arises in
waveguide propagation and is not present in normal-incidence stack
magnetophotonic crystals. Large changes in polarization near the band edges are
observed in first and second orders as a result of the photonic bandgap
structure. Extreme sensitivity to linear birefringence exists in second order.


title:
Low Energy Effective Hamiltonian for a Periodic Array of Cosmological
  Branes : The Smectic Universe

abstract:
  We investigate a simple model of a stack of four dimensional cosmological
branes in a five dimensional flat bulk via the use of a derived low-energy
effective Hamiltonian for a `radion'-like field associated with brane
displacements and deformations. We also extend by analogy the theory of 3D
smectic liquid crystals and multi-lamellar amphiphilic membranes, as are
typically found in soft condensed matter systems, to the 5D case of many
parallel brane universes. The underlying rotational invariance of such a system
implies the absence of an explicit intra-brane cosmological constant term in
the low-energy effective Hamiltonian. The strength of a quadratic inter-brane
potential introduced for stabilisation is calculated self-consistently, and
leads naturally to a novel exponential suppression mechanism for the 4D
intra-brane cosmological constant. We also pursue, again by analogy to the 3D
case, the link between this work and the Abelian Higgs transition, or
superconductivity, in 5D. The relevance of the work presented here in
explicating the cosmological constant problem is also highlighted, outlined and
discussed.


title:
Enhanced relativistic High-Harmonic Generation (HHG) using tailored
  pulses

abstract:
  The interaction of relativistically strong tailored laser pulses with an
atomic system is considered. Due to a special tailoring of the laser pulse, the
suppression of the relativistic drift of the ionized electron and a dramatic
enhancement of the rescattering probability is shown to be achievable. The high
harmonic generation rate in the relativistic regime is calculated and shown to
be increased by several orders of magnitude compared to the case of
conventional laser pulses. The energies of the revisiting electron at the
atomic core can approach the MeV domain, thus rendering hard x-ray harmonics
and nuclear reactions with single atoms feasible.


title:
Statistical distances between countries and cluster structures in EU
  area according to macroeconomic indices fluctuations

abstract:
  The paper applies some recent developments of network analysis in order to
perform a comparative study of EU countries in relation with the fluctuations
of some macroeconomic indicators. The statistical distances between countries,
calculated for various moving average time windows, are mapped into the
ultrametric subdominant space as in classical Minimal Spanning Tree methods.
The novelty consists in applying the so-called Moving Average Minimal Length
Path algorithm, which allows a decoupling of fluctuations with respect to the
mass center of the system from the movement of the mass center itself. The
present analysis pertains to the Gross Domestic Product and some of its sources
for 15 EU countries between 1972 and 2004. It is found that the strongly
correlated countries with respect to GDP fluctuations can be partitioned into
stable clusters. The final structure proves to be stable against the
fluctuations induced by the moving time window over the scanned time interval.


title: Computer-aided hepatic tumour ablation

abstract:
  Surgical resection of hepatic tumours is not always possible. Alternative
techniques consist in locally using chemical or physical agents to destroy the
tumour and this may be performed percutaneously. It requires a precise
localisation of the tumour placement during ablation. Computer-assisted surgery
tools may be used in conjunction to these new ablation techniques to improve
the therapeutic efficiency whilst benefiting from minimal invasiveness. This
communication introduces the principles of a system for computer-assisted
hepatic tumour ablation.


title:
Third-order many-body perturbation theory calculations for the beryllium
  and magnesium isoelectronic sequences

abstract:
  Relativistic third-order MBPT is applied to obtain energies of ions with two
valence electrons in the no virtual-pair approximation (NVPA). A total of 302
third-order Goldstone diagrams are organized into 12 one-body and 23 two-body
terms. Only third-order two-body terms and diagrams are presented here, owing
to the fact that the one-body terms are identical to the previously studied
third-order terms in monovalent ions. Dominant classes of diagrams are
identified. The model potential is a Dirac-Hartree-Fock $V^{N-2}$ potential,
and B-spline basis functions in a cavity of finite radius are employed in the
numerical calculations. The Breit interaction is taken into account through
second order of perturbation theory and the lowest-order Lamb shift is also
evaluated. Sample calculations are performed for berylliumlike ions with Z =
4--7, and for the magnesiumlike ion P IV. The third-order energies are in
excellent agreement with measurement with an accuracy at 0.2% level for the
cases considered. Comparisons are made with previous second-order MBPT results
and with other calculations. The third-order energy correction is shown to be
significant, improving second-order correlation energies by an order of
magnitude.


title:
Optical polarizer/isolator based on a rectangular waveguide with helical
  grooves

abstract:
  A chirality-based approach to making a one-way waveguide that can be used as
an optical isolator or a polarizer is described. The waveguide is rectangular,
and chirality is introduced by making slanted rectangular grooves on the
waveguide walls. Chirality of the waveguide manifests as a strong circular
dichroism, and is responsible for transmitting one circular polarization of
light and reflecting the other. Optical isolation of the propagating circular
polarization is accomplished when the chiral waveguide is placed in front of a
non-chiral optical device. Even the crudest implementations of chirality are
shown to exhibit significant circular dichroism.


title:
Giant transmission and dissipation in perforated films mediated by
  surface phonon polaritons

abstract:
  We experimentally and theoretically study electromagnetic properties of
optically thin silicon carbide (SiC) membranes perforated by an array of
sub-wavelength holes. Giant absorption and transmission is found using Fourier
Transformed Infrared (FTIR) microscopy and explained by introducing a
frequency-dependent effective permittivity $\epsilon_{\rm eff}(\omega)$ of the
perforated film. The value of $\epsilon_{\rm eff}(\omega)$ is determined by the
excitation of two distinct types of hole resonances: a delocalized slow surface
polariton (SSP) whose frequency is largely determined by the array period, and
a localized surface polariton (LSP) which corresponds to the resonances of an
isolated hole. Only SSPs are shown to modify $\epsilon_{\rm eff}(\omega)$
strongly enough to cause giant transmission and absorption.


title: On a Time Variation of Neutrino's Mass

abstract:
  After the introduction to the subject, we review the Machian relations
involving the different kinds of energy densities in the Universe. By suposing
that dark-matter is composed by Neutrino's massive energy, we hint that the
Neutrino's masses should be proportional to the inverse of R, while the total
number of Neutrinos in the Universe increases with the square of R, where R
stands for Hubble's length. This makes possible that the dark mater-energy
density be of Neutrinos origin, to vary with the inverse square of R, as is
necessary for a Machian Universe. The neutrino average mass is estimated for
the present Universe (=10 to the minus 76 power, in grams).


title:
The Photon-Assisted Cascaded Electron Multiplier: a Concept for
  Potential Avalanche-Ion Blocking

abstract:
  We present a Photon-Assisted Cascaded Electron Multipliers (PACEM) which has
a potential for ion back-flow blocking in gaseous radiation detectors: the
avalanche from a first multiplication stage propagates to the successive one
via its photons, which in turn induce photoelectron emission from a
photocathode deposited on the second multiplier stage; the multiplication
process may further continue via electron-avalanche propagation. The
photon-mediated stage allows, by a proper choice of geometry and fields,
complete blocking of the ion back-flow into the first element; thus, only ions
from the latter will flow back to the drift region. The PACEM concept was
validated in a double-MHSP (Micro-Hole & Strip Plate) cascaded multiplier
operated in xenon, where the intermediate scintillation stage provided optical
gain of ~60. The double-MHSP detector had a total gain above 10^4 and energy
resolution of 18% FWHM for 5.9 keV x-rays.


title: Advances in imaging THGEM-based detectors

abstract:
  The thick GEM (THGEM) [1] is an "expanded" GEM, economically produced in the
PCB industry by simple drilling and etching in G-10 or other insulating
materials (fig. 1). Similar to GEM, its operation is based on electron gas
avalanche multiplication in sub-mm holes, resulting in very high gain and fast
signals. Due to its large hole size, the THGEM is particularly efficient in
transporting the electrons into and from the holes, leading to efficient
single-electron detection and effective cascaded operation. The THGEM provides
true pixilated radiation localization, ns signals, high gain and high rate
capability. For a comprehensive summary of the THGEM properties, the reader is
referred to [2, 3]. In this article we present a summary of our recent study on
THGEM-based imaging, carried out with a 10x10 cm^2 double-THGEM detector.


title:
Single-Frequency High-Power Continuous-Wave Oscillation at 1003 nm of an
  Optically Pumped Semiconductor Laser

abstract:
  This work reports single-frequency laser oscillation at 1003.4 nm of an
optically pumped external cavity semiconductor laser. By using a gain structure
bonded onto a high conductivity substrate, we demonstrate both theoretically
and experimentally the strong reduction of the thermal resistance of the active
semiconductor medium, resulting in a high power laser emission. The
spectro-temporal dynamics of the laser is also explained. Furthermore, an
intracavity frequency-doubling crystal was used to obtain a stable single-mode
generation of blue (501.5 nm) with an output power around 60 mW.


title:
Ray-wave correspondence in the nonlinear description of stadium-cavity
  lasers

abstract:
  We show that the solution of fully nonlinear lasing equations for stadium
cavities exhibits a highly directional emission pattern. This directionality
can be well explained by a ray-dynamical model, where the dominant ray-escape
dynamics is governed by the unstable manifolds of the unstable short periodic
orbits for the stadium cavity. Investigating the cold-cavity modes relevant for
the lasing, we found that all of the high-Q modes have the emission
directionality corresponding to that of the ray-dynamical model.


title: Self-organization of price fluctuation distribution in evolving markets

abstract:
  Financial markets can be seen as complex systems in non-equilibrium steady
state, one of whose most important properties is the distribution of price
fluctuations. Recently, there have been assertions that this distribution is
qualitatively different in emerging markets as compared to developed markets.
Here we analyse both high-frequency tick-by-tick as well as daily closing price
data to show that the price fluctuations in the Indian stock market, one of the
largest emerging markets, have a distribution that is identical to that
observed for developed markets (e.g., NYSE). In particular, the cumulative
distribution has a long tail described by a power law with an exponent $\alpha
\approx 3$. Also, we study the historical evolution of this distribution over
the period of existence of the National Stock Exchange (NSE) of India, which
coincided with the rapid transformation of the Indian economy due to
liberalization, and show that this power law tail has been present almost
throughout. We conclude that the ``inverse cubic law'' is a truly universal
feature of a financial market, independent of its stage of development or the
condition of the underlying economy.


title:
Optical Lattice Polarization Effects on Hyperpolarizability of Atomic
  Clock Transitions

abstract:
  The light-induced frequency shift due to the hyperpolarizability (i.e. terms
of second-order in intensity) is studied for a forbidden optical transition,
$J$=0$\to$$J$=0. A simple universal dependence on the field ellipticity is
obtained. This result allows minimization of the second-order light shift with
respect to the field polarization for optical lattices operating at a magic
wavelength (at which the first-order shift vanishes). We show the possibility
for the existence of a magic elliptical polarization, for which the
second-order frequency shift vanishes. The optimal polarization of the lattice
field can be either linear, circular or magic elliptical. The obtained results
could improve the accuracy of lattice-based atomic clocks.


title: 3D Meshes Registration : Application to statistical skull model

abstract:
  In the context of computer assist surgical techniques, a new elastic
registration method of 3D meshes is presented. In our applications, one mesh is
a high density mesh (30000 vertexes), the second is a low density one (1000
vertexes). Registration is based upon the minimisation of a symmetric distance
between both meshes, defined on the vertexes, in a multi resolution approach.
Results on synthetic images are first presented. Then, thanks to this
registration method, a statistical model of the skull is build from Computer
Tomography exams collected for twelve patients.


title: Rigid Registration of Freehand 3D Ultrasound and CT-Scan Kidney Images

abstract:
  This paper presents a method to register a preoperative CT volume to a sparse
set of intraoperative US slices. In the context of percutaneous renal puncture,
the aim is to transfer a planning information to an intraoperative coordinate
system. The spatial position of the US slices is measured by localizing a
calibrated probe. Our method consists in optimizing a rigid 6 degree of freedom
(DOF) transform by evaluating at each step the similarity between the set of US
images and the CT volume. The images have been preprocessed in order to
increase the relationship between CT and US pixels. Correlation Ratio turned
out to be the most accurate and appropriate similarity measure to be used in a
Powell-Brent minimization scheme. Results are compared to a standard rigid
point-to-point registration involving segmentation, and discussed.


title:
A finite element study of the influence of the osteotomy surface on the
  backward displacement during exophthalmia reduction

abstract:
  Exophthalmia is characterized by a protrusion of the eyeball. The most
frequent surgery consists in an osteotomy of the orbit walls to increase the
orbital volume and to retrieve a normal eye position. Only a few clinical
obser-vations have estimated the relationship between the eyeball backward
dis-placement and the decompressed fat tissue volume. This paper presents a
method to determine the relationship between the eyeball backward displace-ment
and the osteotomy surface made by the surgeon, in order to improve
ex-ophthalmia reduction planning. A poroelastic finite element model involving
morphology, material properties of orbital components, and surgical gesture is
proposed to perform this study on 12 patients. As a result, the osteotomy
sur-face seems to have a non-linear influence on the backward displacement.
More-over, the FE model permits to give a first estimation of an average law
linking those two parameters. This law may be helpful in a surgical planning
frame-work.


title:
Comparison of linear and non-linear soft tissue models with
  post-operative CT scan in maxillofacial surgery

abstract:
  A Finite Element model of the face soft tissue is proposed to simulate the
morphological outcomes of maxillofacial surgery. Three modelling options are
implemented: a linear elastic model with small and large deformation
hypothesis, and an hyperelastic Mooney-Rivlin model. An evaluation procedure
based on a qualitative and quantitative comparison of the simulations with a
post-operative CT scan is detailed. It is then applied to one clinical case to
evaluate the differences between the three models, and with the actual patient
morphology. First results shows in particular that for a "simple" clinical
procedure where stress is less than 20%, a linear model seams sufficient for a
correct modelling.


title:
Physical modelling of the airflow-walls interactions to understand the
  sleep apnea syndrome

abstract:
  Sleep Apnea Syndrome (SAS) is defined as a partial or total closure of the
patient upper airways during sleep. The term "collapsus" (or collapse) is used
to describe this closure. From a fluid mechanical point of view, this collapse
can be understood as a spectacular example of fluid-walls interaction. Indeed,
the upper airways are delimited in their largest part by soft tissues having
different geometrical and mechanical properties: velum, tongue and pharyngeal
walls. Airway closure during SAS comes from the interaction between these soft
tissues and the inspiratory flow. The aim of this work is to understand the
physical phenomena at the origin of the collapsus and the metamorphosis in
inspiratory flow pattern that has been reported during SAS. Indeed, a full
comprehension of the physical conditions allowing this phenomenon is a
prerequisite to be able to help in the planning of the surgical gesture that
can be prescribed for the patients. The work presented here focuses on a simple
model of fluid-walls interactions. The equations governing the airflow inside a
constriction are coupled with a Finite Element (FE) biomechanical model of the
velum. The geometries of this model is extracted from a single midsagittal
radiography of a patient. The velar deformations induced by airflow
interactions are computed, presented, discussed and compared to measurements
collected onto an experimental setup.


title:
Models for Planning and Simulation in Computer Assisted Orthognatic
  Surgery

abstract:
  Two aspects required to establish a planning in orthognatic surgery are
addressed in this paper. First, a 3D cephalometric analysis, which is
clini-cally essential for the therapeutic decision. Then, an original method to
build a biomechanical model of patient face soft tissue, which provides
evaluation of the aesthetic outcomes of an intervention. Both points are
developed within a clinical application context for computer aided
maxillofacial surgery.


title:
Simulation of the Exophthalmia Reduction using a Finite Element Model of
  the Orbital Soft Tissues

abstract:
  This paper proposes a computer-assisted system for the surgical treatment of
exophthalmia. This treatment is classically characterized by a de-compression
of the orbit, by the mean of an orbital walls osteotomy. The plan-ning of this
osteotomy consists in defining the size and the location of the de-compression
hole. A biomechanical model of the orbital soft tissues and its in-teractions
with the walls are provided here, in order to help surgeons in the definition
of the osteotomy planning. The model is defined by a generic Finite Element
poro-elastic mesh of the orbit. This generic model is automatically adapted to
the morphologies of four patients, extracted from TDM exams. Four different FE
models are then generated and used to simulate osteotomies in the maxillary or
ethmoid sinuses regions. Heterogeneous results are observed, with different
backwards movements of the ocular globe according to the size and/or the
location of the hole.


title:
A 3D Finite Element model of the face for simulation in plastic and
  maxillo-facial surgery

abstract:
  This paper introduces a new Finite Element biomechanical model of the human
face, which has been developed to be integrated into a simulator for plastic
and maxillo-facial surgery. The idea is to be able to predict, from an
aesthetic and functional point of view, the deformations of a patient face,
resulting from repositioning of the maxillary and mandibular bone structures.
This work will complete the simulator for bone-repositioning diagnosis that has
been developed by the laboratory. After a description of our research project
context, each step of the modeling is precisely described: the continuous and
elastic structure of the skin tissues, the orthotropic muscular fibers and
their insertions points, and the functional model of force generation. First
results of face deformations due to muscles activations are presented. They are
qualitatively compared to the functional studies provided by the literature on
face muscles roles and actions.


title:
Tailoring of motional states in double-well potentials by time-dependent
  processes

abstract:
  We show that the vibrational state tailoring method developed for molecular
systems can be applied for cold atoms in optical lattices. The original method
is based on a three-level model interacting with two strong laser pulses in a
counterintuitive sequence [M. Rodriguez et al., Phys. Rev. A 62, 053413
(2000)]. Here we outline the conditions for achieving similar dynamics with
single time-dependent potential surfaces. It is shown that guided switching
between diabatic and adiabatic evolution has an essential role in this system.
We also show that efficient and precise tailoring of motional states in optical
lattices can be achieved, for instance, simply by superimposing two lattices
and moving them with respect to each other.


title: Of Songs and Men: a Model for Multiple Choice with Herding

abstract:
  We propose a generic model for multiple choice situations in the presence of
herding and compare it with recent empirical results from a Web-based music
market experiment. The model predicts a phase transition between a weak
imitation phase and a strong imitation, `fashion' phase, where choices are
driven by peer pressure and the ranking of individual preferences is strongly
distorted at the aggregate level. The model can be calibrated to reproduce the
main experimental results of Salganik et al. (Science, 311, pp. 854-856
(2006)); we show in particular that the value of the social influence parameter
can be estimated from the data. In one of the experimental situation, this
value is found to be close to the critical value of the model.

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


title: Understanding the tsunami with a simple model

abstract:
  In this paper, we use the approximation of shallow water waves (Margaritondo
G 2005 Eur. J. Phys. 26 401) to understand the behaviour of a tsunami in a
variable depth. We deduce the shallow water wave equation and the continuity
equation that must be satisfied when a wave encounters a discontinuity in the
sea depth. A short explanation about how the tsunami hit the west coast of
India is given based on the refraction phenomenon. Our procedure also includes
a simple numerical calculation suitable for undergraduate students in physics
and engineering.


title:
A Complexity O(1) Priority Queue for Event Driven Molecular Dynamics
  Simulations

abstract:
  We propose and implement a priority queue suitable for use in event driven
molecular dynamics simulations. All operations on the queue take on average
O(1) time per collision. In comparison, previously studied queues for event
driven molecular dynamics simulations require O(log $N$) time per collision for
systems of $N$ particles.


title: Friendly units for coldness

abstract:
  Measures of temperature that center around human experience get lots of use.
Of course thermal physics insights of the last century have shown that
reciprocal temperature (1/kT) has applications that temperature addresses less
well. In addition to taking on negative absolute values under population
inversion (e.g. of magnetic spins), bits and bytes turn 1/kT into an informatic
measure of the thermal ambient for developing correlations within any complex
system. We show here that, in the human-friendly units of bytes and food
Calories, water freezes when 1/kT ~200 ZB/Cal or kT ~5 Cal/YB. Casting familiar
benchmarks into these terms shows that habitable human space requires coldness
values (part of the time, at least) between 0 and 40 ZB/Cal with respect body
temperature ~100 degrees F, a range in kT of ~1 Cal/YB. Insight into these
physical quantities underlying thermal equilibration may prove useful for
budding scientists, as well as the general public, in years ahead.


title: On some applications of Galilean electrodynamics of moving bodies

abstract:
  We discuss the seminal article in which Le Bellac and L\'{e}vy-Leblond have
identified two Galilean limits of electromagnetism [1], and its modern
implications. Recent works have shed a new light on the choice of gauge
conditions in classical electromagnetism. We discuss various applications and
experiments, such as in quantum mechanics, superconductivity, electrodynamics
of continuous media, etc. Much of the current technology, where waves are not
taken into account, is actually based on Galilean electromagnetism


title: Definability in Physics

abstract:
  This paper has been withdrawn because the content has been substantially
improved in a later paper, arXiv:0806.1165.


title: Enhanced Molecular Orientation Induced by Molecular Anti-Alignment

abstract:
  We explore the role of laser induced anti-alignment in enhancing molecular
orientation. A field-free enhanced orientation via anti-alignment scheme is
presented, which combines a linearly polarized femtosecond laser pulse with a
half-cycle pulse. The laser pulse induces transient anti-alignment in the plane
orthogonal to the field polarization, while the half-cycle pulse leads to the
orientation. We identify two qualitatively different enhancement mechanisms
depending on the pulse order, and optimize their effects using classical and
quantum models both at zero and non-zero temperature.


title: A stable fiber-based Fabry-Perot cavity

abstract:
  We report the development of a fiber-based, tunable optical cavity with open
access. The cavity is of the Fabry-Perot type and is formed with miniature
spherical mirrors positioned on the end of single- or multi-mode optical fibers
by a transfer technique which involves lifting a high-quality mirror from a
smooth convex substrate, either a ball lens or micro-lens. The cavities
typically have a finesse of $\sim 1,000$ and a mode volume of 600 $\mu$m$^3$.
We demonstrate the detection of small ensembles of cold Rb atoms guided through
such a cavity on an atom chip.


title:
The mesh-matching algorithm: an automatic 3D mesh generator for Finite
  element structures

abstract:
  Several authors have employed Finite Element Analysis (FEA) for stress and
strain analysis in orthopaedic biomechanics. Unfortunately, the use of
three-dimensional models is time consuming and consequently the number of
analysis to be performed is limited. The authors have investigated a new method
allowing automatically 3D mesh generation for structures as complex as bone for
example. This method called Mesh-Matching (M-M) algorithm generated
automatically customized 3D meshes of bones from an already existing model. The
M-M algorithm has been used to generate FE models of ten proximal human femora
from an initial one which had been experimentally validated. The new meshes
seemed to demonstrate satisfying results.


title:
Einstein's theory of wavefronts versus Einstein's relativity of
  simultaneity

abstract:
  The relativity of simultaneity implies that the image of a Lorentz
transformed (LT) spherical (circular) wavefront is not a spherical (circular)
wavefront (Einstein 1905) but an ellipsoidal (elliptical) wavefront (Moreau,
Am.J.of Phys).We show firstly that the relativity of simultaneity leads to the
consequence that the image of a Lorentz transformed plane wavefront is a
tangent plane to an ellipsoid and not a tangent plane to a sphere (Einstein
1905). We deduce then a longitudinal component of the tangent vector to
Poincare's ellipse which is directly connected to the relativity of
simultaneity. We suggest finally that this violation of relativity of
simultaneity is related to Einstein's implicit choice of the (non relativistic)
transverse gauge in his theory of (rigid) wavefronts.


title:
Focusing inversion techniques applied to electrical resistance
  tomography in an experimental tank

abstract:
  We present an algorithm for focusing inversion of electrical resistivity
tomography (ERT) data. ERT is a typical example of ill-posed problem.
Regularization is the most common way to face this kind of problems; it
basically consists in using a priori information about targets to reduce the
ambiguity and the instability of the solution. By using the minimum gradient
support (MGS) stabilizing functional, we introduce the following geometrical
prior information in the reconstruction process: anomalies have sharp
boundaries. The presented work is embedded in a project (L.A.R.A.) which aims
at the estimation of hydrogeological properties from geophysical
investigations. L.A.R.A. facilities include a simulation tank (4 m x 8 m x 1.35
m); 160 electrodes are located all around the tank and used for 3-D ERT.
Because of the large number of electrodes and their dimensions, it is important
to model their effect in order to correctly evaluate the electrical system
response. The forward modelling in the presented algorithm is based on the
so-called complete electrode model that takes into account the presence of the
electrodes and their contact impedances. In this paper, we compare the results
obtained with different regularizing functionals applied on a synthetic model.


title:
Investigation of the Chaotic Dynamics of an Electron Beam with a Virtual
  Cathode in an External Magnetic Field

abstract:
  The effect of the strength of the focusing magnetic field on chaotic dynamic
processes occurring inan electron beam with a virtual cathode, as well as on
the processes whereby the structures form in the beamand interact with each
other, is studied by means of two-dimensional numerical simulations based on
solving a self-consistent set of Vlasov-Maxwell equations. It is shown that, as
the focusing magnetic field is decreased,the dynamics of an electron beam with
a virtual cathode becomes more complicated due to the formation andinteraction
of spatio-temporal longitudinal and transverse structures in the interaction
region of a vircator. The optimum efficiency of the interaction of an electron
beam with the electromagnetic field of the vircator isachieved at a
comparatively weak external magnetic field and is determined by the
fundamentally two-dimensional nature of the motion of the beam electrons near
the virtual cathode.


title: Surface EM waves on 1D Photonic Crystals

abstract:
  We study surface states of 1D photonic crystals using a semiclassical coupled
wave theory. Both TE and TM modes are treated. We derive analytic
approximations that clarify the systematics of the dispersion relations, and
the roles of the various parameters defining the crystal.