title: Saturable Absorber, Coherent Population Oscillations, and "Slow Light"

abstract:
  The paper presents a critical analysis of publications devoted to one of the
methods for production of the so-called "slow light" (the light with an
anomalously low group velocity) due to extremely high local steepness of the
dispersion curve of the medium. The method in point employs for this purpose
the effect of coherent population oscillations accompanied by burning of a
narrow spectral hole in the homogeneously broadened absorption spectrum.
Physical model of the effect proposed in the studies under consideration is
based on analysis of response of a nonlinear medium to a low-frequency
intensity modulation of the incident light beam. We show that all the
observations described in these papers can be easily interpreted in the
framework of the simplest model of saturable absorber and have nothing to do
with the effects of hole burning and group velocity reduction.


title: Flux surface shaping effects on tokamak edge turbulence and flows

abstract:
  Shaping of magnetic flux surfaces is found to have a strong impact on
turbulence and transport in tokamak edge plasmas. A series of axisymmetric
equilibria with varying elongation and triangularity, and a divertor
configuration are implemented into a computational gyrofluid turbulence model.
The mechanisms of shaping effects on turbulence and flows are identified.
Transport is mainly reduced by local magnetic shearing and an enhancement of
zonal shear flows induced by elongation and X-point shaping.


title: Complex Network Properties of Chinese Natural Science Basic Research

abstract:
  In this paper, we studied the research areas of Chinese natural science basic
research from a point view of complex network. Two research areas are
considered to be connected if they appear in one fund proposal. The explicit
network of such connections using data from 1999 to 2004 is constructed. The
analysis of the real data shows that the degree distribution of the {\bf
research areas network} (RAN) may be better fitted by the exponential
distribution. It displays small world effect in which randomly chosen pairs of
research areas are typically separated by only a short path of intermediate
research areas. The average distance of RAN decreases with time, while the
average clustering coefficient increases with time, which indicates that the
scientific study would like to be integrated together in terms of the studied
areas. The relationship between the clustering coefficient $C(k)$ and the
degree $k$ indicates that there is no hierarchical organization in RAN.


title: Creativity leading to discoveries in particle physics and relativity

abstract:
  The basic ingredients of the discovery creativity is presented.
Understanding, problem solving, heuristics, computer thinking, technology and
physics, and so on. We present some discoveries from the viewpoint of
creativity. The Dirac equation, the Riccati equation, the nonlinear
Schroedinger equation, the quantum navier Sokes equation, the equation of the
quantum magnetohydrodynamics and so on. We discuss nonlinear Lorentz
transformation involving the maximal acceleration which we relate to the
Hagedorn temperature, and possible dependence of mass on acceleration. We
consider the relation between physics and technology and so on.


title:
Temporal Effects of Agent Aggregation in the Dynamics of Multiagent
  Systems

abstract:
  We propose a model of multiagent systems whose agents have a tendency to
balance their decisions in time. We find phase transitions to oscillatory
behavior, explainable by the aggregation of agents into two groups. On a longer
time scale, we find that the aggregation of smart agents is able to explain the
lifetime distribution of epochs to 8 decades of probability.


title: Kinetic electrostatic structures in current-carrying pair plasmas

abstract:
  The existence and properties of phase-space structures in current-carrying
pair plasmas is studied by means of the finite amplitude expressions of the
pseudo-potential method. Emphasis is given to double layers, solitary
structures and periodic waves. The results can be applied to electron-positron
plasmas as well as to plasmas containing heavier charged particles with the
same mass and opposite charges, such as fullerene ions and dust particles. They
can also help to understand numerical simulations that showed the spontaneous
formation of phase-space holes in linearly stable regimes.


title:
Ultrahigh Interference Spatial Compression of Light Inside the
  Subwavelength Aperture of a Near-Field Optical Probe

abstract:
  Spatial effects of interference and interaction of light modes in the
subwavelength part of the near-field optical microscopy probe have been
theoretically studied. It was found that the mode interference can lead to
higher spatial compression of light (lambda = 500 nm in free space) within the
transverse size of 25 nm inside the probe output aperture of 100 nm in
diameter. The results principally demonstrate the possibility of increasing
spatial resolution of the near-field optical microscopy technique.


title: Nonlinear absorption of ultrashort laser pulses in thin metal films

abstract:
  Self-consistent simulations of the ultrafast electron dynamics in thin metal
films are performed. A regime of nonlinear oscillations is observed, which
corresponds to ballistic electrons bouncing back and forth against the film
surfaces. When an oscillatory laser field is applied to the film, the field
energy is partially absorbed by the electron gas. Maximum absorption occurs
when the period of the external field matches the period of the nonlinear
oscillations, which, for sodium films, lies in the infrared range. Possible
experimental implementations are discussed.


title:
Ericson fluctuations in an open, deterministic quantum system: theory
  meets experiment

abstract:
  We provide numerically exact photoexcitation cross sections of rubidium
Rydberg states in crossed, static electric and magnetic fields, in quantitative
agreement with recent experimental results. Their spectral backbone underpins a
clear transition towards the Ericson regime.


title: Rigorous theory of nuclear fusion rates in a plasma

abstract:
  Real-time thermal field theory is used to reveal the structure of plasma
corrections to nuclear reactions. Previous results are recovered in a fashion
that clarifies their nature, and new extensions are made. Brown and Yaffe have
introduced the methods of effective quantum field theory into plasma physics.
They are used here to treat the interesting limiting case of dilute but very
highly charged particles reacting in a dilute, one-component plasma. The highly
charged particles are very strongly coupled to this background plasma. The
effective field theory proves that this mean field solution plus the one-loop
term dominate; higher loop corrections are negligible even though the problem
involves strong coupling. Such analytic results for very strong coupling are
rarely available, and they can serve as benchmarks for testing computer models.

categories: physics.plasm-ph astro-ph math-ph math.MP


title: Highly charged ions in a weakly coupled plasma: an exact solution

abstract:
  The ion sphere model introduced long ago by Salpeter is placed in a rigorous
theoretical setting. The leading corrections to this model for very highly
charged but dilute ions in thermal equilibrium with a weakly coupled,
one-component background plasma are explicitly computed, and the subleading
corrections are shown to be negligibly small. Such analytic results for very
strong coupling are rarely available, and they can serve as benchmarks for
testing computer models in this limit.


title: Computation of Internal Fluid Flows in Channels Using the Package CFX-5

abstract:
  The paper presents the results of computation of some simple internal flows
of incompressible fluid with the software package CFX-5. In the previous paper
of the author, the same flows were used for testing of another CFD software
tool, FlowVision. The model equations used for this research are again the set
of Reynolds and continuity equations and equations of the standard k - e
turbulence model. The results of computation of a number of internal fluid
flows in channels are presented and comparison with known experimental data is
performed. Good correspondence of results was obtained both concerning the flow
pattern and related integral values.


title:
Capabilities of Numerical Simulation of Multiphase Flows in Centrifugal
  Pumps using Modern CFD Software

abstract:
  The paper describes capabilities of numerical simulation of liquid flows with
solid and/or gas admixtures in centrifugal pumps using modern commercial CFD
software packages, with the purpose to predict performance curves of the pumps
treating such media. In particular, the approaches and multiphase flow models
available in the package CFX-5 are described; their advantages and
disadvantages are analyzed.


title: An empirical behavioral model of price formation

abstract:
  Although behavioral economics has demonstrated that there are many situations
where rational choice is a poor empirical model, it has so far failed to
provide quantitative models of economic problems such as price formation. We
make a step in this direction by developing empirical models that capture
behavioral regularities in trading order placement and cancellation using data
from the London Stock Exchange. For order placement we show that the
probability of placing an order at a given price is well approximated by a
Student distribution with less than two degrees of freedom, centered on the
best quoted price. This result is surprising because it implies that trading
order placement is symmetric, independent of the bid-ask spread, and the same
for buying and selling. We also develop a crude but simple cancellation model
that depends on the position of an order relative to the best price and the
imbalance between buying and selling orders in the limit order book. These
results are combined to construct a stochastic representative agent model, in
which the orders and cancellations are described in terms of conditional
probability distributions. This model is used to simulate price formation and
the results are compared to real data from the London Stock Exchange. Without
adjusting any parameters based on price data, the model produces good
predictions for the magnitude and functional form of the distribution of
returns and the bid-ask spread.


title: Artscience (AS) in Classical and Quantum Physics: Paper I

abstract:
  A general methodology and specific formalism are used to restrict the
Copenhagen interpretation of quantum mechanics. A natural psi-collapse to
reality is developed in an equation with terms independent of the measuring
equipment.
  The theory requires one of three experiments for the ensemble average of
position, momentum, or energy, or a probability-experiment.
  Both classically and quantum mechanically, we define Artscience (AS) as
Logic-Epistemology in Physics, where epistemology is treated as phenomenology.
AS (logic phenomenology) is thus shown to be related to Physics
(formalism-data) .


title:
Physics of the enhanced optical cooling of particle beams in storage
  rings

abstract:
  Physics of enhanced optical cooling of particle beams in storage rings,
nonlinear features of cooling and requirements to ring lattices, optical and
laser systems are discussed


title: Atom-molecule collisions in an optically trapped gas

abstract:
  Cold inelastic collisions between confined cesium (Cs) atoms and Cs$\_2$
molecules are investigated inside a CO$\_2$ laser dipole trap. Inelastic
atom-molecule collisions can be observed and measured with a rate coefficient
of $\sim 2.5 \times 10^{-11} $cm$^3$ s$^{-1}$, mainly independent of the
molecular ro-vibrational state populated. Lifetimes of purely atomic and
molecular samples are essentially limited by rest gas collisions. The pure
molecular trap lifetime ranges 0,3-1 s, four times smaller than the atomic one,
as is also observed in a pure magnetic trap. We give an estimation of the
inelastic molecule-molecule collision rate to be $\sim 10^{-11}$ cm$^{3}$
s$^{-1}$.


title: Secular cycle of the north-south solar asymmetry

abstract:
  The North-South asymmetry of solar activity has been recognized for different
solar phenomena. Following Waldmeier, it is now assumed that solar activity
dominates in the Northern solar hemisphere during the ascending part of the
secular solar cycle, in the Southern one during the descending part, and in
epochs of secular minima and maxima the asymmetry is small. The episodes when
this rule does not hold (the Maunder minimum in the end of the 17th century,
and 19th and 20th solar cycles in the 20th century secular maximum) are
considered as "anomalies". Analyzing solar activity influence on climate, we
come to the conclusion that the asymmetry differs not in the ascending and
descending parts of the secular solar cycles, but in consecutive secular
cycles. This hypothesis is in agreement with all available data and leaves no
anomalies.


title: The high-temperature phase transition in a plasma

abstract:
  The line of phase equilibrium between the hot and cold phases of a plasma is
derived from the intensity of thermal radiation as a function of the plasma
density and temperature. The last function is obtained with the help of the
condition for emission relating the wavelength of radiation and the plasma
density.


title: Vortex Stretching and Reconnection in a Compressible Fluid

abstract:
  Vortex stretching in a compressible fluid is considered. Two-dimensional and
axisymmetric cases are considered separately. The flows associated with the
vortices are perpendicular to the plane of the uniform straining flows.
Externally-imposed density build-up near the axis leads to enhanced compactness
of the vortices - "dressed" vortices (in analogy to "dressed" charged particles
in a dielectric system). The compressible vortex flow solutions in the 2D as
well as axisymmetric cases identify a length scale relevant for the
compressible case which leads to the Kadomtsev-Petviashvili spectrum for
compressible turbulence. Vortex reconnection process in a compressible fluid is
shown to be possible even in the inviscid case - compressibility leads to
defreezing of vortex lines in the fluid.


title: Gravitational Waves: new observatories for new astronomy

abstract:
  This article reviews the current status of gravitational wave astronomy and
explains why astronomers are excited about the new generation of gravitational
wave detectors. As part of the review we compare and contrast gravitational
radiation to the more familiar electromagnetic radiation. We discuss the
current indirect experimental evidence for gravitational waves, and how current
and future gravitational wave detectors will operate as our newest telescopes
pointed at the skies.


title:
Q-factor and emission pattern control of the WG modes in notched
  microdisk resonators

abstract:
  Two-dimensional (2-D) boundary integral equation analysis of a notched
circular microdisk resonator is presented. Results obtained provide accurate
description of optical modes, free from the staircasing and discretization
errors of other numerical techniques. Splitting of the double degenerate
Whispering-Gallery (WG) modes and directional light output is demonstrated. The
effect of the notch depth and width on the resonance wavelengths, Q-factors,
and emission patterns is studied. Further improvement of the directionality is
demonstrated in an elliptical notched microdisk. Applications of the notched
resonators to the design of microdisk lasers, oscillators, and biosensors are
discussed.


title:
Symmetry, degeneracy and optical confinement of modes in coupled
  microdisk resonators and photonic crystal cavities

abstract:
  Fast and highly accurate method based on the Muller contour integral
equations and a trigonometric-trigonometric Galerkin discretization technique
is presented for spectral design and fine-tuning of clusters of
whispering-gallery (WG) mode microdisk resonators and photonic crystal (PC)
defect cavities. It is shown that degeneracy and near-degeneracy of natural
modes as well as modes optical confinement in coupled resonator clusters are
significantly influenced by the symmetry of the structure. Photonic molecules
with greatly enhanced quality factors are designed by exploiting the symmetry
of the molecular geometry and tuning the inter-cavity coupling distances.
Potential applications of the spectrally engineered coupled-resonator
structures to low-threshold microdisk lasers, optical biosensors, and random
powder lasers are discussed.


title:
Reconstruction of Atomic Ionization Probabilities in Intense Laser
  Fields

abstract:
  Application of a parallel-projection inversion technique to z-scan spectra of
multiply charged xenon and krypton ions, obtained by non-resonant field
ionization of neutral targets, has for the first time permitted the direct
observation of intensity-dependent ionization probabilities. These ionization
efficiency curves have highlighted the presence of structure in the tunnelling
regime, previously unobserved under full-volume techniques.


title:
From the lab to the battlefield? Nanotechnology and fourth generation
  nuclear weapons

abstract:
  The paper addresses some major implications of microelectromechanical systems
(MEMS) engineering and nanotechnology for the improvement of existing types of
nuclear weapons, and the development of more robust versions of these weapons,
as well as for the development of fourth generations nuclear weapons in which
nanotechnology will play an essential role.


title: The Decrease in Physics Enrollment

abstract:
  We discuss and analyze the fact that physics is generally losing its ability
to captivate students who may possess the potential to enhance the quality of
our future in this age of technology. We have tried to investigate the reasons
behind this low enrollment in the light of the results of a few surveys with
the undergraduate students in different physics courses and in current relevant
college programs. It is not an exclusively descriptive issue, so our analysis
is a way to delineate the details of the matter leading to the suggestions for
future improvements.


title:
Fine-structure Constant, Anomalous Magnetic Moment, Relativity Factor
  and the Golden Ratio that Divides the Bohr Radius

abstract:
  Sommerfeld introduced the fine-structure constant into physics, while he was
taking into account the relativistic effects in the theory of the hydrogen
atom. Ever since, it has puzzled many scientists like Eddington, Dirac, Feynman
and others. Here the mysterious fine-structure constant, alpha = (Compton
wavelength/de Broglie wavelength) = 1/137.036 = 2.627/360 is interpreted based
on the finding that it is close to 2.618/360 = 1/137.508, where the Compton
wavelength for hydrogen is a distance equivalent to an arc length on the
circumference (given by the de Broglie wavelength) of a circle with the Bohr
radius and 2.618 is the square of the Golden ratio, which was recently shown to
divide the Bohr radius into two Golden sections at the point of electrical
neutrality. From the data for the electron (e) and proton (p) g-factors, it is
found that (137.508 - 137.036)= 0.472 = [g(p) - g(e)]/[g(p) + g(e)] (= 2/cube
of the Golden ratio), and that (2.627 - 2.618)/360 = (small part of the Compton
wavelength corresponding to the intrinsic radii of e and p/de Broglie
wavelength) = 0.009/360 = (1- gamma)/gamma, the factor for the advance of
perihilion in Sommerfeld's theory of the hydrogen atom, where gamma is the
relativity factor.


title:
Response maxima in time-modulated turbulence: Direct Numerical
  Simulations

abstract:
  The response of turbulent flow to time-modulated forcing is studied by direct
numerical simulations of the Navier-Stokes equations. The large-scale forcing
is modulated via periodic energy input variations at frequency $\omega$. The
response is maximal for frequencies in the range of the inverse of the large
eddy turnover time, confirming the mean-field predictions of von der Heydt,
Grossmann and Lohse (Phys. Rev. E 67, 046308 (2003)). In accordance with the
theory the response maximum shows only a small dependence on the Reynolds
number and is also quite insensitive to the particular flow-quantity that is
monitored, e.g., kinetic energy, dissipation-rate, or Taylor-Reynolds number.
At sufficiently high frequencies the amplitude of the kinetic energy response
decreases as $1/\omega$. For frequencies beyond the range of maximal response,
a significant change in phase-shift relative to the time-modulated forcing is
observed.


title: The optimal form of the scanning near-field optical microscopy probe

abstract:
  A theoretical approach to determine the optimal form of the near-field
optical microscope probe is proposed. An analytical expression of the optimal
probe form with subwavelength aperture has been obtained. The advantages of the
probe with the optimal form are illustrated using numerical calculations. The
conducted calculations show 10 times greater light throughput and the reception
possibility of the more compactly localized light at the output probe aperture
which could indicate better spatial resolution of the optical images in
near-field optical technique using optimal probe.


title:
On Higher Order Gravities, Their Analogy to GR, and Dimensional
  Dependent Version of Duff's Trace Anomaly Relation

abstract:
  An almost brief, though lengthy, review introduction about the long history
of higher order gravities and their applications, as employed in the
literature, is provided. We review the analogous procedure between higher order
gravities and GR, as described in our previous works, in order to highlight its
important achievements. Amongst which are presentation of an easy
classification of higher order Lagrangians and its employment as a
\emph{criteria} in order to distinguish correct metric theories of gravity. For
example, it does not permit the inclusion of only one of the second order
Lagrangians in \emph{isolation}. But, it does allow the inclusion of the
cosmological term. We also discuss on the compatibility of our procedure and
the Mach idea. We derive a dimensional dependent version of Duff's trace
anomaly relation, which in \emph{four}-dimension is the same as the usual Duff
relation. The Lanczos Lagrangian satisfies this new constraint in \emph{any}
dimension. The square of the Weyl tensor identically satisfies it independent
of dimension, however, this Lagrangian satisfies the previous relation only in
three and four dimensions.


title: Trap-induced resonances in controlled collisions of cesium atoms

abstract:
  We consider the feasibility of observing a trap-induced resonance [Stock et
al., Phys. Rev. Lett. 91, 183201 (2003)] for the case of two 133Cs atoms,
trapped in separated wells of a polarization-gradient optical lattice, and
interacting through a multichannel scattering process. Due to the anomalously
large scattering length of cesium dimers, a strong coupling can occur between
vibrational states of the trap and a weakly bound molecular state that is made
resonant by the ac-Stark shift of the lattice. We calculate the energy spectrum
of the two-atom system as a function of the distance between two potential
wells by connecting the solutions of the Schroedinger equation for the
short-range molecular potential to that of the long-range trap in a
self-consistent manner. The short-range potential is treated through a
multichannel pseudopotential, parametrized by the K matrix, calculated
numerically for atoms in free space in a close-coupling approximation. This
captures both the bound molecular spectrum as well as the energy-dependent
scattering for all partial waves. We establish realistic operating conditions
under which the trap-induced resonance could be observed and show that this
strong and coherent interaction could be used as a basis for high-fidelity
two-qubit quantum logic operations.


title:
Exciton matter sustained by colossal dispersive interactions due to
  enhanced polarizability: Possible clue to ball lightning

abstract:
  Recently Gilman has pointed out that the material state of a ball lightning
is both highly cohesive and flexible. He makes a specific proposal for a
cohesive state arising from (colossal) Van-der-Waals attraction between highly
polarizable Rydberg atoms produced under a linear lightning. We accept his
general suggestions but propose that the colossal Van-der-Waals coupling may
also arise from the enhanced polarizability of surrogate molecular clusters,
due to the polaron gap narrowing effect. We consider a few illuminating cases
and present calculations for the ammonia molecule. Although being unable to
identify the exact nature of the surrogate molecules at least for the
time-being, we suggest a general scenario of photoexcited vibronic excitons
forming a supersaturated surrogate gas phase in which a ball arises as a result
of condensation. The orange color of the luminous ball is due to radiative
exciton deexcitation and suggests that there may be a unique surrogate material
for ball lightning.


title:
Proposals for Two Satellite-Borne Experiments to Test Relativity of
  Simultaneity in Special Relativity

abstract:
  An orbiting `photon clock' is proposed to test directly the relativity of
simultaneity effect of special relativity. This is done by exchanging microwave
signals between two satellites in low Earth orbit carrying clocks that have
previously been synchronised in the Earth-centered inertial system. A similar
experiment using synchronised signals from two GPS satellites with the receiver
on a single satellite in low Earth orbit, is also proposed.


title:
Study of systematic effects in beta decay measurements with AgReO4
  calorimeters

abstract:
  AgReO4 microcalorimeters are planned to be used again in the next generation
of calorimetric neutrino mass experiments with sensitivity down to 0.2 eV. The
understanding and characterization of all possible sources of systematic
uncertainties is crucial. In this work we focus on two of these sources, which
have been studied in the 10 detectors of the Milano AgReO4 array experiment
(MIBETA): a) the solid-state Beta Environmental Fine Structure (BEFS) observed
for the first time in AgReO4; b) the detector energy response for internal beta
events, which has been investigated with a dedicated measurement using a 44Ti
gamma source. The possible effects on neutrino mass experiments due to the
incomplete understanding of these two aspects are discussed.


title: An Ultrasonic analog for a laser

abstract:
  We report measurements on ultrasonic systems analogous to random lasers. One
system entails unstable ultrasonic feedback between distinct transducers,
another involves a piezoelectric device that emits spontaneously and by
stimulation. Both systems are found to exhibit behaviors similar to those of
lasers. Over a wide range of parameters we observe narrow single emission
lines, sensitivity to linear cavity properties, complex multi-mode emissions,
and line narrowing.


title:
Comment on: "Estimating the Hartree-Fock limit from finite basis set
  calculations" [Jensen F (2005) Theor Chem Acc 113:267]

abstract:
  We demonstrate that a minor modification of the extrapolation proposed by
Jensen [(2005): Theor Chem Acc 113:267] yields very reliable estimates of the
Hartree-Fock limit in conjunction with correlation consistent basis sets.
Specifically, a two-point extrapolation of the form
$E_{HF,L}=E_{HF,\infty}+A(L+1)\exp(-9\sqrt{L})$ yields HF limits
$E_{HF,\infty}$ with an RMS error of 0.1 millihartree using aug-cc-pVQZ and
aug-cc-pV5Z basis sets, and of 0.01 millihartree using aug-cc-pV5Z and
aug-cc-pV6Z basis sets.


title: Management Fads, Pedagogies and Soft Technologies

abstract:
  We present a model for the diffusion of management fads and other
technologies which lack clear objective evidence about their merits. The
choices made by non-Bayesian adopters reflect both their own evaluations and
the social influence of their peers. We show, both analytically and
computationally, that the dynamics lead to outcomes that appear to be
deterministic in spite of being governed by a stochastic process. In other
words, when the objective evidence about a technology is weak, the evolution of
this process quickly settles down to a fraction of adopters that is not
predetermined. When the objective evidence is strong, the proportion of
adopters is determined by the quality of the evidence and the adopters'
competence.


title: Optical microscopy via spectral modifications of a nano-antenna

abstract:
  The existing optical microscopes form an image by collecting photons emitted
from an object. Here we report on the experimental realization of microscopy
without the need for direct optical communication with the sample. To achieve
this, we have scanned a single gold nanoparticle acting as a nano-antenna in
the near field of a sample and have studied the modification of its intrinsic
radiative properties by monitoring its plasmon spectrum.


title:
Theory of Quantum Gravity of photon confirms experimental results of a
  varying fine structure constant while Quantum Mechanics leads to String
  theory

abstract:
  Quantum Mechanics of photons leads to a theory of Quantum Gravity that nicely
matches the experimental results of varying fine structure constant,obtained
from many-multiplet Quaser absorption systems and atomic clocks.The variation
of that constant is due to quantum gravity of photons,created by their non-zero
invariant mass.The photon mass is obtained from a Klein-Gordon scalar
tachyon.This led to a Lorentz symmetry-breaking and varying speed of light
theory in complex spacetime manifold.In essence,Quantum Mechanics includes
quantum gravitational potential in the guise of quantum potential.The greatest
surprise lies in showing that Quantum Mechanics naturally leads to open bosonic
string whose troublesome tachyonic vibration is taken in its stride.Quantum
Mechanics also proves Sen`s second conjecture and space-tearing.Length melts
into dimensionless number at the Planck scale.Quantum-mechanical analog of the
mass-energy equation has been derived and a dispersion relation demonstrates
Lorentz non-invariance in Quantum Mechanics.


title:
On the Statistical Viewpoint Concerning the 2nd Law of Thermodynamics a
  Reminder on the Ehrenfests' Urn Model

abstract:
  In statistical thermodynamics the 2nd law is properly spelled out in terms of
conditioned probabilities. As such it makes the statement, that `entropy
increases with time' without preferring a time direction. In this paper I try
to explain this statement--which is well known since the time of the
Ehrenfests--in some detail within a systematic Bayesian approach.


title:
The Thin Gap Chambers database experience in test beam and preparations
  for ATLAS

abstract:
  Thin gap chambers (TGCs) are used for the muon trigger system in the forward
region of the LHC experiment ATLAS. The TGCs are expected to provide a trigger
signal within 25 ns of the bunch spacing. An extensive system test of the ATLAS
muon spectrometer has been performed in the H8 beam line at the CERN SPS during
the last few years. A relational database was used for storing the conditions
of the tests as well as the configuration of the system. This database has
provided the detector control system with the information needed for
configuration of the front end electronics. The database is used to assist the
online operation and maintenance. The same database is used to store the non
event condition and configuration parameters needed later for the offline
reconstruction software. A larger scale of the database has been produced to
support the whole TGC system. It integrates all the production, QA tests and
assembly information. A 1/12th model of the whole TGC system is currently in
use for testing the performance of this database in configuring and tracking
the condition of the system. A prototype of the database was first implemented
during the H8 test beams. This paper describes the database structure, its
interface to other systems and its operational performance.


title:
System Test of the ATLAS Muon Spectrometer in the H8 Beam at the CERN
  SPS

abstract:
  An extensive system test of the ATLAS muon spectrometer has been performed in
the H8 beam line at the CERN SPS during the last four years. This spectrometer
will use pressurized Monitored Drift Tube (MDT) chambers and Cathode Strip
Chambers (CSC) for precision tracking, Resistive Plate Chambers (RPCs) for
triggering in the barrel and Thin Gap Chambers (TGCs) for triggering in the
end-cap region. The test set-up emulates one projective tower of the barrel
(six MDT chambers and six RPCs) and one end-cap octant (six MDT chambers, A CSC
and three TGCs). The barrel and end-cap stands have also been equipped with
optical alignment systems, aiming at a relative positioning of the precision
chambers in each tower to 30-40 micrometers. In addition to the performance of
the detectors and the alignment scheme, many other systems aspects of the ATLAS
muon spectrometer have been tested and validated with this setup, such as the
mechanical detector integration and installation, the detector control system,
the data acquisition, high level trigger software and off-line event
reconstruction. Measurements with muon energies ranging from 20 to 300 GeV have
allowed measuring the trigger and tracking performance of this set-up, in a
configuration very similar to the final spectrometer. A special bunched muon
beam with 25 ns bunch spacing, emulating the LHC bunch structure, has been used
to study the timing resolution and bunch identification performance of the
trigger chambers. The ATLAS first-level trigger chain has been operated with
muon trigger signals for the first time.


title:
Experiments in Principle for the Artscience (AS) Interpretation: Paper
  II

abstract:
  The physics of wavefunction collapse from Hilbert space to a classically real
spacetime, accompanied by wave-particle duality, is, fundamentally, reduction
of the complex psi to reality. We introduce new terminology for new physics.
The superposition sigma ~ psi + phi of system and apparatus is postulated. A
simple and obvious thing to test is the ensemble probability (Sect. 1).
Weinberg (2005) suggests three types of experiments for energy, position, and
momentum observable ensemble averages which should all be tested (Sect. 2 - 4).
This Reference is intended to serve as general background for the present paper
which is self-contained.


title: Stationary Ballistic 'V' States for Preferred Motions of Many Particles

abstract:
  We use the discrete kinetic theory with the free-orientation parameter being
fixed ($\pi/4$) to derive the macroscopic velocity field for many particles
flowing through a microdomain. Our results resemble qualitatively other
hydrodynamical solutions. The V-shaped velocity field changes as the dominant
physical parameter (Knudsen number) varies. We also briefly discuss the
possible mechanism due to the entropy production along the boundaries.


title:
Illustrating the space-time coordinates of the events associated with
  the apparent and the actual position of a light source

abstract:
  We present a space-time diagram that displays in true values the space- time
coordinates of events associated with the apparent and actual positions of a
point like source moving with constant velocity. We use it in order to
construct the actual shape of a moving luminous profile or to determine the
relationship between apparent and actual distances. We show that the simple
fact that light propagates at finite speed has important consequences like
"length contraction" or "length dilation" the effects being sensitive against
the "approaching" and the "receding" character of the source relative to an
observer located at the origin of the inertial reference frame


title: Geometrical theory of whispering gallery modes

abstract:
  Using quasiclassical approach rather precise analytical approximations for
the eigenfrequencies of whispering gallery modes in convex axisymmetric bodies
may be found. We use the eikonal method to analyze the limits of precision of
quasiclassical approximation using as a practical example spheroidal dielectric
cavity. The series obtained for the calculation of eigenfrequencies is compared
with the known series for dielectric sphere and with numerical calculations. We
show how geometrical interpretation allows expansion of the method on arbitrary
shaped axisymmetric bodies.


title:
A Fourier (k-) space design approach for controllable photonic band and
  localization states in aperiodic lattices

abstract:
  In this paper we present a systematic study of photonic bandgap engineering
using aperiodic lattices (ALs). Up to now ALs have tended to be defined by
specific formulae (e.g. Fibonacci, Cantor), and theories have neglected other
useful ALs along with the vast majority of non-useful (random) ALs. Here, we
present a practical and efficient Fourier space-based general theory to
identify all those ALs having useful band properties, which are characterized
by well-defined Fourier (i.e. lattice momentum) components. Direct control of
field localization comes via control of the Parseval strength competition
between the different Fourier components characterizing a lattice. Real-space
optimization of ALs tends to be computationally demanding. However, via our
Fourier space-based simulated annealing inverse optimization algorithm, we
efficiently tailor the relative strength of the AL Fourier components for
precise control of photonic band and localization properties.


title: Pumped quantum systems: immersion fluids of the future?

abstract:
  Quantum optical techniques may yield immersion fluids with high indices of
refraction without absorption. We describe one such technique in which a probe
field experiences a large index of refraction with amplification rather than
absorption, and examine its practicality for an immersion lithography
application. Enhanced index can be observed in a three-level system with a
tunable, near-resonant, coherent probe and incoherent pump field that inverts
population of the probe transition. This observation contradicts the common
belief that large indices of refraction are impossible without absorption,
however it is well in accord with existing electromagnetic theory and practice.
Calculations show that a refractive index >> 2 is possible with practical
experimental parameters. A scheme with an incoherent mixture of pumped and
unpumped atoms is also examined, and is seen to have a lower refractive index
(~2) accompanied by neither gain nor loss.


title:
Gradient Symplectic Algorithms for Solving the Radial Schrodinger
  Equation

abstract:
  The radial Schrodinger equation for a spherically symmetric potential can be
regarded as a one dimensional classical harmonic oscillator with a
time-dependent spring constant. For solving classical dynamics problems,
symplectic integrators are well known for their excellent conservation
properties. The class of {\it gradient} symplectic algorithms is particularly
suited for solving harmonic oscillator dynamics. By use of Suzuki's rule for
decomposing time-ordered operators, these algorithms can be easily applied to
the Schrodinger equation. We demonstrate the power of this class of gradient
algorithms by solving the spectrum of highly singular radial potentials using
Killingbeck's method of backward Newton-Ralphson iterations.


title: Modeling the Internet

abstract:
  We model the Internet as a network of interconnected Autonomous Systems which
self-organize under an absolute lack of centralized control. Our aim is to
capture how the Internet evolves by reproducing the assembly that has led to
its actual structure and, to this end, we propose a growing weighted network
model driven by competition for resources and adaptation to maintain
functionality in a demand and supply ``equilibrium''. On the demand side, we
consider the environment, a pool of users which need to transfer information
and ask for service. On the supply side, ASs compete to gain users, but to be
able to provide service efficiently, they must adapt their bandwidth as a
function of their size. Hence, the Internet is not modeled as an isolated
system but the environment, in the form of a pool of users, is also a
fundamental part which must be taken into account. ASs compete for users and
big and small come up, so that not all ASs are identical. New connections
between ASs are made or old ones are reinforced according to the adaptation
needs. Thus, the evolution of the Internet can not be fully understood if just
described as a technological isolated system. A socio-economic perspective must
also be considered.


title: Polydispersity Effects in the Dynamics and Stability of Bubbling Flows

abstract:
  The occurrence of swarms of small bubbles in a variety of industrial systems
enhances their performance. However, the effects that size polydispersity may
produce on the stability of kinematic waves, the gain factor, mean bubble
velocity, kinematic and dynamic wave velocities is, to our knowledge, not yet
well established. We found that size polydispersity enhances the stability of a
bubble column by a factor of about 23% as a function of frequency and for a
particular type of bubble column. In this way our model predicts effects that
might be verified experimentally but this, however, remain to be assessed. Our
results reinforce the point of view advocated in this work in the sense that a
description of a bubble column based on the concept of randomness of a bubble
cloud and average properties of the fluid motion, may be a useful approach that
has not been exploited in engineering systems.


title:
Near-field enhancement and imaging in double cylindrical
  polariton-resonant structures: Enlarging perfect lens

abstract:
  We experimentally demonstrate a prototype of a cylindrical enlarging lens
capable of enhancing and restoring evanescent fields. The enabling phenomenon
is the resonant excitation of coupled surface modes in a system of two
cylindrical arrays of small resonant particles. As was shown in [J. Appl. Phys.
96, 1293 (2004)], this phenomenon in planar arrays can be used in
electromagnetic near-field imaging. Here, we use a similar structure in a
cylindrically symmetric configuration, which gives us a possibility to obtain
an enlarged near-field image.


title:
Design and performance of LED calibration system prototype for the lead
  tungstate crystal calorimeter

abstract:
  A highly stable monitoring system based on blue and red light emitting diodes
coupled to a distribution network comprised of optical fibers has been
developed for an electromagnetic calorimeter that uses lead tungstate crystals
readout with photomultiplier tubes. We report of the system prototype design
and on the results of laboratory tests. Stability better than 0.1% (r.m.s.) has
been achieved during one week of prototype operation.


title: Towards Sustainable Future by Transition to the Next Level Civilisation

abstract:
  Universal and rigorously derived concept of dynamic complexit
(physics/9806002) shows that any system of interacting components, including
society and civilisation, exists only as a process of highly inhomogeneous,
qualitative development of its complexity. Modern state of civilisation
corresponds to the end of unfolding of a big enough level of complexity. Such
exhausted, totally "replete" structure cannot be sustainable in principle and
shows instead increased instability, realising its inevitable replacement by a
new kind of structure with either low or much higher level of complexity
(degrading or progressive development branch, respectively). Unrestricted
sustainability can emerge only after transition to the next, superior level of
civilisation complexity, which implies qualitative and unified changes in all
aspects of life, including knowledge, production, social organisation, and
infrastructure. These changes are specified by the rigorous analysis of
underlying interaction processes. The unitary, effectively one-dimensional and
rigidly fixed kind of thinking, knowledge, and social structure at the current
level of complexity will be replaced by "dynamically multivalued",
intrinsically creative kind of structure at the forthcoming superior level of
development. We propose mathematically rigorous description of unreduced
civilisation complexity development, including universal criterion of progress.
One obtains thus a working basis for the causally complete, objectively exact
and reliable development science and futurology.


title: Random Matrix Filtering in Portfolio Optimization

abstract:
  We study empirical covariance matrices in finance. Due to the limited amount
of available input information, these objects incorporate a huge amount of
noise, so their naive use in optimization procedures, such as portfolio
selection, may be misleading. In this paper we investigate a recently
introduced filtering procedure, and demonstrate the applicability of this
method in a controlled, simulation environment.


title:
Nonextensive Interpretation Of Radiative Recombination In Electron
  Cooling

abstract:
  An interest for the low-energy range of the nonextensive distribution
function arises from the study of radiative recombination in electron cooling
devices in particle accelerators, whose experimentally measured reaction rates
are much above the theoretical prediction. The use of generalized
distributions, that differ from the Maxwellian in the low energy part (due to
subdiffusion between electron and ion bunches), may account for the observed
rate enhancement. In this work, we consider the isotropic distribution function
and we propose a possible experiment for verifying the existence of a cut-off
in the generalized momentum distribution, by measuring the spectrum of the
X-rays emitted from radiative recombination reactions.


title: Exact numerical simulation of power-law noises

abstract:
  Many simulations of stochastic processes require colored noises: I describe
here an exact numerical method to simulate power-law noises: the method can be
extended to more general colored noises, and is exact for all time steps, even
when they are unevenly spaced (as may often happen for astronomical data, see
e.g. N. R. Lomb, Astrophys. Space Sci. {\bf 39}, 447 (1976)). The algorithm has
a well-behaved computational complexity, it produces a nearly perfect Gaussian
noise, and its computational efficiency depends on the required degree of noise
Gaussianity.


title: Covariant kinetic theory of nonlinear plasma waves interaction

abstract:
  A rigorous and most general covariant kinetic formalism is developed to study
the nonlinear waves interaction in relativistic Vlasov plasmas. The typical
nonlinear plasma reaction is a nonlinear current measured by the nonlinear
plasma conductivity, and these quantities are derived here on the basis of
relativistic Vlasov-Maxwell equations. Knowing the nonlinear plasma
conductivity allows us to determine all plasma modes nonlinearly excited in
plasma. The general covariant form of nonlinear conductivity is provided first
for any value of plasma temperature and for the whole complex frequency plane
by a correct analytical continuation. The further analysis is restricted to a
correct relativistic particle distribution which is vanishing for particle
speeds greater than speed of light. In the limit of nonrelativistic plasma
temperatures the covariant nonlinear conductivity is significantly different
from the standard noncovariant nonrelativistic results which are reached only
in the formal limit of an infinitely large speed of light $c \to \infty$.


title:
A High Temperature Calcium Vapor Cell for Spectroscopy on the 4s^2 1S0
  to 4s4p 3P1 Intercombination Line

abstract:
  We have demonstrated a high temperature vapor cell for absorption
spectroscopy on the Ca intercombination line. The cell uses a dual chamber
design to achieve the high temperatures necessary for an optically dense vapor
while avoiding the necessity of high temperature vacuum valves and
glass-to-metal seals. We have observed over 50 percent absorption in a single
pass through the cell. Although pressure broadening in the cell prevented us
from performing saturated-absorption spectroscopy, the broadening resulted in
higher signal-to-noise ratios by allowing us to probe the atoms with
intensities much greater than the 0.2 uW/cm^2 saturation intensity of the
unbroadened transition.


title: Condensation in an Economic Model with Brand Competition

abstract:
  We present a linear agent based model on brand competition. Each agent
belongs to one of the two brands and interacts with its nearest neighbors. In
the process the agent can decide to change to the other brand if the move is
beneficial. The numerical simulations show that the systems always condenses
into a state when all agents belong to a single brand. We study the
condensation times for different parameters of the model and the influence of
different mechanisms to avoid condensation, like anti monopoly rules and brand
fidelity.


title:
A Flux-Conservative Formalism for Convective and Dissipative Multi-Fluid
  Systems, with Application to Newtonian Superfluid Neutron Stars

abstract:
  We develop a flux-conservative formalism for a Newtonian multi-fluid system,
including dissipation and entrainment (i.e. allowing the momentum of one fluid
to be a linear combination of the velocities of all fluids). Maximum use is
made of mass, energy, and linear and angular momentum conservation to specify
the equations of motion. Also used extensively are insights gleaned from a
convective variational action principle, key being the distinction between each
velocity and its canonically conjugate momentum. Dissipation is incorporated to
second order in the ``thermodynamic forces'' via the approach pioneered by
Onsager. An immediate goal of the investigation is to understand better the
number, and form, of independent dissipation terms required for a consistent
set of equations of motion in the multi-fluid context. A significant, but
seemingly innocuous detail, is that one must be careful to isolate ``forces''
that can be written as total gradients, otherwise errors can be made in
relating the net internal force to the net externally applied force. Our
long-range aim is to provide a formalism that can be used to model dynamical
multi-fluid systems both perturbatively and via fully nonlinear 3D numerical
evolutions. To elucidate the formalism we consider the standard model for a
heat-conducting, superfluid neutron star, which is believed to be dominated by
superfluid neutrons, superconducting protons, and a highly degenerate,
ultra-relativistic gas of normal fluid electrons. We determine that in this
case there are, in principle, 19 dissipation coefficients in the final set of
equations.


title:
Mathematical methods of factorization and a feedback approach for
  biological systems

abstract:
  The first part of the thesis is devoted to factorizations of linear and
nonlinear differential equations leading to solutions of the kink type. The
second part contains a study of the synchronization of the chaotic dynamics of
two Hodgkin-Huxley neurons by means of the mathematical tools belonging to the
geometrical control theory.


title: Characteristic Length Scale of Electric Transport Properties of Genomes

abstract:
  A tight-binding model together with a novel statistical method are used to
investigate the relation between the sequence-dependent electric transport
properties and the sequences of protein-coding regions of complete genomes. A
correlation parameter $\Omega$ is defined to analyze the relation. For some
particular propagation length $w_{max}$, the transport behaviors of the coding
and non-coding sequences are very different and the correlation reaches its
maximal value $\Omega_{max}$. $w_{max}$ and \omax are characteristic values for
each species. The possible reason of the difference between the features of
transport properties in the coding and non-coding regions is the mechanism of
DNA damage repair processes together with the natural selection.


title:
Comment on Unified treatment for two-center one-electron molecular
  integrals over Slater-type orbitals with integer and noninteger principal
  quantum numbers

abstract:
  In a recent paper Ozdogan (Z. Naturforsch, 59a(2004)743) published formulas
for evaluating the two-center overlap and nuclear attraction integrals over
integer and noninteger Slater type orbitals. The purpose of this article is to
point out that the same formulas have previously been established by Guseinov
et al. (J.Mol.Model.,8(2002)272) by using the same method. As we demonstrated
in our Comment (Int.J.Quantum Chem., 91(2003)62), the expansion formula for the
product of two normalized associated Legendre functions in elliptical
coordinates and the expansion coefficients presented by Ozdogan are obtained
from the use of given in our papers general formulas (I.I.Guseinov,
J.Phys.,B,3(1970)1399; Phys.Rev.,A,32(1985)1864; J.Mol.Struct
(Theochem),336(1995)17) by changing the summation indices. It should be noted
that the published by Ozdogan results are on the use of formulas for the
evaluation of multicenter integrals presented in his other papers, which are
also obtained from the literature (see, e.g., C.C.J. Roothaan, J.Chem.Phys., 19
(1951) 1445; A.Lofthus, Mol. Phys., 5 (1962) 105) and our articles by changing
the summation indices (see Comments: I.I.Guseinov, Commun.Theor.Phys., 38
(2002) 256; Int.J.Quantum Chem., 91 (2003) 62; J.Math.Chem., 36 (2004) 123;
J.Chin.Chem.Soc., 51 (2004) 877; J. Chin. Chem. Soc., 51 (2004) 1077;
I.I.Guseinov, B.A.Mamedov, Can.J.Phys., 82(2004) 205, p.206).


title: Role of connectivity in congestion and decongestion in networks

abstract:
  We study network traffic dynamics in a two dimensional communication network
with regular nodes and hubs. If the network experiences heavy message traffic,
congestion occurs due to finite capacity of the nodes. We discuss strategies to
manipulate hub capacity and hub connections to relieve congestion and define a
coefficient of betweenness centrality (CBC), a direct measure of network
traffic, which is useful for identifying hubs which are most likely to cause
congestion. The addition of assortative connections to hubs of high CBC
relieves congestion very efficiently.


title:
Electron-hydrogen excitation to the n=3 and n=4 levels in the Glauber
  approximation

abstract:
  We have calculated the differential and integrated cross sections for
excitation of atomic hydrogen to its n=3 and n=4 levels by electron impact
using the Glauber approximation. Results are compared with measurements at 20,
30, 40, and 60 eV and also shown for 120 and 480 eV. At momentum transfers not
too large at all energies considered, the calculated n=3 differential cross
sections are qualitatively similar to but a factor of somewhat less than 3
larger than the calculated n=4 cross sections. The calculated integrated cross
sections attain broad maxima near 41 eV.


title: Social inertia in collaboration networks

abstract:
  This work is a study of the properties of collaboration networks employing
the formalism of weighted graphs to represent their one-mode projection. The
weight of the edges is directly the number of times that a partnership has been
repeated. This representation allows us to define the concept of "social
inertia" that measures the tendency of authors to keep on collaborating with
previous partners. We use a collection of empirical datasets to analyze several
aspects of the social inertia: 1) its probability distribution, 2) its
correlation with other properties, and 3) the correlations of the inertia
between neighbors in the network. We also contrast these empirical results with
the predictions of a recently proposed theoretical model for the growth of
collaboration networks.


title:
Estimate solar contribution to the global surface warming using the
  ACRIM TSI satellite composite

abstract:
  We study, by using a wavelet decomposition methodology, the solar signature
on global surface temperature data using the ACRIM total solar irradiance
satellite composite by Willson and Mordvinov. These data present a
+0.047%/decade trend between minima during solar cycles 21-23 (1980-2002). We
estimate that the ACRIM upward trend might have minimally contributed
$\sim$10-30% of the global surface temperature warming over the period
1980-2002.


title:
Multiscaling comparative analysis of time series and geophysical
  phenomena

abstract:
  Different methods are used to determine the scaling exponents associated with
a time series describing a complex dynamical process, such as those observed in
geophysical systems. Many of these methods are based on the numerical
evaluation of the variance of a diffusion process whose step increments are
generated by the data. An alternative method focuses on the direct evaluation
of the scaling coefficient of the Shannon entropy of the same diffusion
distribution. The combined use of these methods can efficiently distinguish
between fractal Gaussian and L\'{e}vy-walk time series and help to discern
between alternative underling complex dynamics.


title:
An econophysics approach to analyse uncertainty in financial markets: an
  application to the Portuguese stock market

abstract:
  In recent years there has been a closer interrelationship between several
scientific areas trying to obtain a more realistic and rich explanation of the
natural and social phenomena. Among these it should be emphasized the
increasing interrelationship between physics and financial theory. In this
field the analysis of uncertainty, which is crucial in financial analysis, can
be made using measures of physics statistics and information theory, namely the
Shannon entropy. One advantage of this approach is that the entropy is a more
general measure than the variance, since it accounts for higher order moments
of a probability distribution function. An empirical application was made using
data collected from the Portuguese Stock Market.


title:
Statistical theory of spectra: Statistical moments as descriptors in the
  theory of molecular similarity

abstract:
  Statistical moments of the intensity distributions are used as molecular
descriptors. They are used as a basis for defining similarity distances between
two model spectra. Parameters which carry the information derived from the
comparison of shapes of the spectra and are related to the number of properties
taken into account, are defined.


title:
Relation between stress heterogeneity and aftershock rate in the
  rate-and-state model

abstract:
  We estimate the rate of aftershocks triggered by a heterogeneous stress
change, using the rate-and-state model of Dieterich [1994].We show that an
exponential stress distribution Pt(au) ~exp(-tautau_0) gives an Omori law decay
of aftershocks with time ~1/t^p, with an exponent p=1-A sigma_n/tau_0, where A
is a parameter of the rate-and-state friction law, and \sigma_n the normal
stress. Omori exponent p thus decreases if the stress "heterogeneity" tau_0
decreases. We also invert the stress distribution P(tau) from the seismicity
rate R(t), assuming that the stress does not change with time. We apply this
method to a synthetic stress map, using the (modified) scale invariant "k^2"
slip model [Herrero and Bernard, 1994]. We generate synthetic aftershock
catalogs from this stress change.The seismicity rate on the rupture area shows
a huge increase at short times, even if the stress decreases on average.
Aftershocks are clustered in the regions of low slip, but the spatial
distribution is more diffuse than for a simple slip dislocation. Because the
stress field is very heterogeneous, there are many patches of positive stress
changes everywhere on the fault.This stochastic slip model gives a Gaussian
stress distribution, but nevertheless produces an aftershock rate which is very
close to Omori's law, with an effective p<=1, which increases slowly with time.
We obtain a good estimation of the stress distribution for realistic catalogs,
when we constrain the shape of the distribution. However, there are probably
other factors which also affect the temporal decay of aftershocks with time. In
particular, heterogeneity of A\sigma_n can also modify the parameters p and c
of Omori's law. Finally, we show that stress shadows are very difficult to
observe in a heterogeneous stress context.


title:
Calculation of isotope shifts and relativistic shifts in CI, CII, CIII
  and CIV

abstract:
  We present an accurate ab initio method of calculating isotope shifts and
relativistic shifts in atomic spectra. We test the method on neutral carbon and
three carbon ions. The relativistic shift of carbon lines may allow them to be
included in analyses of quasar absorption spectra that seek to measure possible
variations in the fine structure constant, alpha, over the lifetime of the
Universe. Carbon isotope shifts can be used to measure isotope abundances in
gas clouds: isotope abundances are potentially an important source of
systematic error in the alpha-variation studies. These abundances are also
needed to study nuclear reactions in stars and supernovae, and test models of
chemical evolution of the Universe.


title: Detecting overlapping communities in linear time with P&A algorithm

abstract:
  This paper describes a new algorithm - P&A algorithm - utilized in
identifying overlapping communities in non oriented valued graph regardless of
their number or their size. The complexity of this algorithm is minimal in the
matter that the number of operations grows linearly with the number of
vertices.


title: Reduced-symmetry two-dimensional solitons in photonic lattices

abstract:
  We demonstrate theoretically and experimentally a novel type of localized
beams supported by the combined effects of total internal and Bragg reflection
in nonlinear two-dimensional square periodic structures. Such localized states
exhibit strong anisotropy in their mobility properties, being highly mobile in
one direction and trapped in the other, making them promising candidates for
optical routing in nonlinear lattices.


title: Analysis of Binarized High Frequency Financial Data

abstract:
  A non-trivial probability structure is evident in the binary data extracted
from the up/down price movements of very high frequency data such as
tick-by-tick data for USD/JPY. In this paper, we analyze the Sony bank USD/JPY
rates, ignoring the small deviations from the market price. We then show there
is a similar non-trivial probability structure in the Sony bank rate, in spite
of the Sony bank rate's having less frequent and larger deviations than
tick-by-tick data. However, this probability structure is not found in the data
which has been sampled from tick-by-tick data at the same rate as the Sony bank
rate. Therefore, the method of generating the Sony bank rate from the market
rate has the potential for practical use since the method retains the
probability structure as the sampling frequency decreases.


title: Small scale behavior of financial data

abstract:
  A new approach is presented to describe the change in the statistics of the
log return distribution of financial data as a function of the timescale. To
this purpose a measure is introduced, which quantifies the distance of a
considered distribution to a reference distribution. The existence of a small
timescale regime is demonstrated, which exhibits different properties compared
to the normal timescale regime. This regime seems to be universal for
individual stocks. It is shown that the existence of this small timescale
regime is not dependent on the special choice of the distance measure or the
reference distribution. These findings have important implications for risk
analysis, in particular for the probability of extreme events.


title: Impact of global seismicity on sea level change assessment

abstract:
  We analyze the effect of seismic activity on sealevel variations, by
computing the time-dependent vertical crustal movement and geoid change due to
coseismic deformations and postseismic relaxation effects. Seismic activity can
affect both the absolute sealevel, by changing the Earth gravity field and
hence the geoid height, and the relative sealevel, i.e. the radial distance
between seafloor and geoid level. By using comprehensive seismic catalogues we
assess the net effect of seismicity on tidal relative sealevel measurements as
well as on the global oceanic surfaces, and we obtain an estimate of absolute
sealevel variations of seismic origin.
  Our results confirm that, on a global scale, most of the signal is associated
with few giant thrust events, and that RSL estimates obtained using tide-gauge
data can be sensibly affected by the seismic driven sealevel signal.
  The recent measures of sealevel obtained by satellite altimetry show a wide
regional variation of sealevel trends over the oceanic surfaces, with the
largest deviations from the mean trend occurring in tectonically active
regions. While our estimates of average absolute sealevel variations turn out
to be orders of magnitude smaller than the satellite measured variations, we
can still argue that mass redistribution associated with aseismic tectonic
processes may contribute to the observed regional variability of sealevel
variations.


title:
Classification of electromagnetic resonances in finite inhomogeneous
  three-dimensional structures

abstract:
  We present a simple and unified classification of macroscopic electromagnetic
resonances in finite arbitrarily inhomogeneous isotropic dielectric 3D
structures situated in free space. By observing the complex-plane dynamics of
the spatial spectrum of the volume integral operator as a function of angular
frequency and constitutive parameters we identify and generalize all the usual
resonances, including complex plasmons, real laser resonances in media with
gain, and real quasi-static resonances in media with negative permittivity and
gain.


title: Asymptotic theory for a moving droplet driven by a wettability gradient

abstract:
  An asymptotic theory is developed for a moving drop driven by a wettability
gradient. We distinguish the mesoscale where an exact solution is known for the
properly simplified problem. This solution is matched at both -- the advancing
and the receding side -- to respective solutions of the problem on the
microscale. On the microscale the velocity of movement is used as the small
parameter of an asymptotic expansion. Matching gives the droplet shape,
velocity of movement as a function of the imposed wettability gradient and
droplet volume.


title:
Finding the mass-energy counterpart to the transverse Doppler shift:
  Avoiding de Broglie's paradox

abstract:
  This paper identifies specific angles of emission and reception of light for
which there exists a mass-energy counterpart to the well known transverse
Doppler shift. At these angles, the relationship of proper and relative
frequency is the same as that for proper and relative mass-energy of a source.
Paradoxically, the transverse Doppler shift is often used to demonstrate that
for specific angles of emission and reception the relationship of proper and
relative frequency of light is the same as that for proper and relative time.
But by carefully defining angles, this apparent paradox is resolved.


title:
Three-dimensional visualisation of tracks in OPERA nuclear emulsion
  films

abstract:
  The possibility of a three-dimensional visualisation/reconstruction of tracks
in nuclear emulsion films using X-ray imaging is described in this paper. The
feasibility of the technique is established with experimental results.


title:
Increasing the output of a Littman-type laser by use of an intracavity
  Faraday rotator

abstract:
  We present a new method of external-cavity diode laser grating stabilization
which combines the high output power of the Littrow design with the fixed
output pointing of the Littman-Metcalf design. Our new approach utilizes a
Faraday-effect optical isolator inside the external cavity. Experimental
testing and a model which describes the tuning range and optimal tuning
parameters of the laser are described. Preliminary testing of this design has
resulted in a short-term linewidth of 360 kHz and a side-mode suppression of 37
dB. The laser tunes mode-hop free over 7 GHz and we predict that much larger
tuning ranges are possible.


title:
Self-referenced prism deflection measurement schemes with microradian
  precision

abstract:
  We have demonstrated several inexpensive methods which can be used to measure
the deflection angles of prisms with microradian precision. The methods are
self-referenced, using various reversals to achieve absolute measurements
without the need of a reference prism or any expensive precision components
other than the prisms under test. These techniques are based on laser
interferometry and have been used in our lab to characterize parallel-plate
beamsplitters, penta prisms, right angle prisms, and corner cube reflectors
using only components typically available in an optics lab.


title:
Nuclear Charge Radius of Li-9, Li-11: Halo Neutron: the influence of
  Halo Neutrons

abstract:
  The nuclear charge radius of Li-11 has been determined for the first time by
high precision laser spectroscopy. On-line measurements at TRIUMF-ISAC yielded
a Li-7 - Li-11 isotope shift (IS) of 25101.23(13) MHz for the Doppler-free 2s -
3s transition. IS precision for all other bound Li isotopes was also improved.
Differences from calculated mass-based IS yield values for change in charge
radius along the isotope chain. The charge radius decreases monotonically from
Li-6 to Li-9, and then increases from 2.217(35) fm to 2.467(37) fm for Li-11.
This is compared to various models, and it is found that a combination of halo
neutron correlation and intrinsic core excitation best reproduces the
experimental results.


title: Tera-sample-per-second Real-time Waveform Digitizer

abstract:
  We demonstrate a real-time transient waveform digitizer with a record 1 TSa/s
(Tera-Sample/sec) sampling rate. This is accomplished by using a photonic time
stretch preprocessor which slows down the electrical waveform before it is
captured by an electronic digitizer.


title:
Laser in the axial electric field as a tool to search for P-, T-
  invariance violation

abstract:
  We consider rotation of polarization plane of the laser light when a gas
laser is placed in a longitudinal electric field (10~kV/cm). It is shown that
residual anisotropy of the laser cavity 10^{-6} and the sensitivity to the
angle of polarization plane rotation about 10^{-11} -10^{-12} rad allows one to
measure an electron EDM with the sensitivity about 10^{-30} e cm.


title: Investigation of a generalized Obukhov Model for Turbulence

abstract:
  We introduce a generalization of Obukhov's model [A.M. Obukhov, Adv. Geophys.
6, 113 (1959)] for the description of the joint position-velocity statistics of
a single fluid particle in fully developed turbulence. In the presented model
the velocity is assumed to undergo a continuous time random walk. This takes
into account long time correlations. As a consequence the evolution equation
for the joint position-velocity probability distribution is a Fokker-Planck
equation with a fractional time derivative. We determine the solution of this
equation in the form of an integral transform and derive a relation for
arbitrary single time moments. Analytical solutions for the joint probability
distribution and its moments are given.


title: Negative Refractive Index in Optics of Metal-Dielectric Composites

abstract:
  Specially designed metal-dielectric composites can have a negative refractive
index in the optical range. Specifically, it is shown that arrays of single and
paired nanorods can provide such negative refraction. For pairs of metal rods,
a negative refractive index has been observed at 1.5 micrometer. The inverted
structure of paired voids in metal films may also exhibit a negative refractive
index. A similar effect can be accomplished with metal strips in which the
refractive index can reach -2. The refractive index retrieval procedure and the
critical role of light phases in determining the refractive index is discussed.


title:
Truncated Sum Rules and their use in Calculating Fundamental Limits of
  Nonlinear Susceptibilities

abstract:
  Truncated sum rules have been used to calculate the fundamental limits of the
nonlinear susceptibilities; and, the results have been consistent with all
measured molecules. However, given that finite-state models result in
inconsistencies in the sum rules, it is not clear why the method works. In this
paper, the assumptions inherent in the truncation process are discussed and
arguments based on physical grounds are presented in support of using truncated
sum rules in calculating fundamental limits. The clipped harmonic oscillator is
used as an illustration of how the validity of truncation can be tested; and,
several limiting cases are discussed as examples of the nuances inherent in the
method.


title:
Liquid interfaces in viscous straining flows: Numerical studies of the
  selective withdrawal transition

abstract:
  This paper presents a numerical analysis of the transition from selective
withdrawal to viscous entrainment. In our model problem, an interface between
two immiscible layers of equal viscosity is deformed by an axisymmetric
withdrawal flow, which is driven by a point sink located some distance above
the interface in the upper layer. We find that steady-state hump solutions,
corresponding to selective withdrawal of liquid from the upper layer, cease to
exist above a threshold withdrawal flux, and that this transition corresponds
to a saddle-node bifurcation for the hump solutions. Numerical results on the
shape evolution of the steady-state interface are compared against previous
experimental measurements. We find good agreement where the data overlap.
However, the numerical results' larger dynamic range allows us to show that the
large increase in the curvature of the hump tip near transition is not
consistent with an approach towards a power-law cusp shape, an interpretation
previously suggested from inspection of the experimental measurements alone.
Instead the large increase in the curvature at the hump tip reflects a
logarithmic coupling between the overall height of the hump and the curvature
at the tip of the hump.


title: Monte Carlo simulation of melting transition on DNA nanocompartment

abstract:
  DNA nanocompartment is a typical DNA-based machine whose function is
dependent of molecular collective effect. Fundamental properties of the device
have been addressed via electrochemical analysis, fluorescent microscopy, and
atomic force microscopy. Interesting and novel phenomena emerged during the
switching of the device. We have found that DNAs in this system exhibit a much
steep melting transition compared to ones in bulk solution or conventional DNA
array. To achieve an understanding to this discrepancy, we introduced DNA-DNA
interaction potential to the conventional Ising-like Zimm-Bragg theory and
Peyrard-Bishop model of DNA melting. To avoid unrealistic numerical calculation
caused by modification of the Peyrard-Bishop nonlinear Hamiltonian with the
DNA-DNA interaction, we established coarse-gained Monte Carlo recursion
relations by elucidation of five components of energy change during melting
transition. The result suggests that DNA-DNA interaction potential accounts for
the observed steep transition.


title: Chaotic desynchronization of multi-strain diseases

abstract:
  Multi-strain diseases are diseases that consist of several strains, or
serotypes. The serotypes may interact by antibody-dependent enhancement (ADE),
in which infection with a single serotype is asymptomatic, but infection with a
second serotype leads to serious illness accompanied by greater infectivity. It
has been observed from serotype data of dengue hemorrhagic fever that outbreaks
of the four serotypes occur asynchronously. Both autonomous and seasonally
driven outbreaks were studied in a model containing ADE. For sufficiently small
ADE, the number of infectives of each serotype synchronizes, with outbreaks
occurring in phase. When the ADE increases past a threshold, the system becomes
chaotic, and infectives of each serotype desynchronize. However, certain
groupings of the primary and second ary infectives remain synchronized even in
the chaotic regime.


title: Equation of state for partially ionized carbon at high temperatures

abstract:
  Equation of state for partially ionized carbon at temperatures T > ~ 10^5 K
is calculated in a wide range of densities, using the method of free energy
minimization in the framework of the chemical picture of plasmas. The free
energy model includes the internal partition functions of bound species. The
latter are calculated by a self-consistent treatment of each ionization stage
in the plasma environment taking into account pressure ionization. The
long-range Coulomb interactions between ions and screening of the ions by free
electrons are included using our previously published analytical model.


title: There's more to volatility than volume

abstract:
  It is widely believed that fluctuations in transaction volume, as reflected
in the number of transactions and to a lesser extent their size, are the main
cause of clustered volatility. Under this view bursts of rapid or slow price
diffusion reflect bursts of frequent or less frequent trading, which cause both
clustered volatility and heavy tails in price returns. We investigate this
hypothesis using tick by tick data from the New York and London Stock Exchanges
and show that only a small fraction of volatility fluctuations are explained in
this manner. Clustered volatility is still very strong even if price changes
are recorded on intervals in which the total transaction volume or number of
transactions is held constant. In addition the distribution of price returns
conditioned on volume or transaction frequency being held constant is similar
to that in real time, making it clear that neither of these are the principal
cause of heavy tails in price returns. We analyze recent results of Ane and
Geman (2000) and Gabaix et al. (2003), and discuss the reasons why their
conclusions differ from ours. Based on a cross-sectional analysis we show that
the long-memory of volatility is dominated by factors other than transaction
frequency or total trading volume.


title: Turbulent-laminar patterns in plane Couette flow

abstract:
  Regular patterns of turbulent and laminar fluid motion arise in plane Couette
flow near the lowest Reynolds number for which turbulence can be sustained. We
study these patterns using an extension of the minimal flow unit approach to
simulations of channel flows pioneered by Jimenez and Moin. In our case,
computational domains are of minimal size in only two directions. The third
direction is taken to be large. Furthermore, the long direction can be tilted
at any prescribed angle to the streamwise direction. We report on different
patterned states observed as a function of Reynolds number, imposed tilt, and
length of the long direction. We compare our findings to observations in large
aspect-ratio experiments.


title:
Positron annihilation in $e^+ -$H collision above the Positronium
  formation threshold

abstract:
  A long-standing problem to account for the electron-positron annihilation in
positron Hydrogen scattering above the Positronium formation threshold has been
resolved by the use of the three-body Faddeev formalism. The multichannel
three-body theory for scattering states in presence of a complex absorbing
potential is developed in order to compute the direct $e^+ e^-$ annihilation
amplitude, the amplitude of Positronium formation and respective cross
sections. A number of $e^+ e^-$ direct annihilation cross sections and
Positronium formation cross sections in the energy gap between Ps$(1s)$ and
H$(n=2)$ thresholds are reported for both the positron-Hydrogen incoming
channel as well as the proton-Positronium incoming channel.


title: The cubic period-distance relation for the Kater reversible pendulum

abstract:
  We describe the correct cubic relation between the mass configuration of a
Kater reversible pendulum and its period of oscillation. From an analysis of
its solutions we conclude that there could be as many as three distinct mass
configurations for which the periods of small oscillations about the two pivots
of the pendulum have the same value. We also discuss a real compound Kater
pendulum that realizes this property.


title: Model-based fit procedure for power-law-like spectra

abstract:
  $1/f^\alpha$ noises are ubiquitous and affect many measurements. These noises
are both a nuisance and a peculiarity of several physical systems; in
dielectrics, glasses and networked liquids it is very common to study this
noise to gather useful information. Sometimes it happens that the noise has a
power-law shape only in a certain frequency range, and contains other important
features, that are however difficult to study because simple fits often fail.
Here I propose a model-based fit procedure that performs well on spectra
obtained in a molecular dynamics simulation.


title:
On Mathematical Defect in Demonstration of Convection Theorem:
  Implications For Continuum Mechanics and Other Classical Field Theories

abstract:
  Serious mathematical defect in the important kinematics theorem known in
continuum mechanics as Convection (or Transport) Theorem is reported. We claim
that the traditional demonstration does not take into account a special
constraint on integrand functions given in Lagrangian representation. Thus, we
put in doubt that the traditional procedure for the transition from integral
formulations of physical laws of some classical field theories to their
differential form is mathematically rigorous. Reconsidered formulation shows
the way how the system of fundamental differential equations of continuum
mechanics and some other field theories could be modified without any change of
the original integral formulation. The continuity equation and the differential
form of the equation of motion for continuous media are discussed as examples
of modification.


title:
On Two Complementary Types of Total Time Derivative in Classical Field
  Theories and Maxwell's Equations

abstract:
  Close insight into mathematical and conceptual structure of classical field
theories shows serious inconsistencies in their common basis. In other words,
we claim in this work to have come across two severe mathematical blunders in
the very foundations of theoretical hydrodynamics. One of the defects concerns
the traditional treatment of time derivatives in Eulerian hydrodynamic
description. The other one resides in the conventional demonstration of the
so-called Convection Theorem. Both approaches are thought to be necessary for
cross-verification of the standard differential form of continuity equation.
Any revision of these fundamental results might have important implications for
all classical field theories. Rigorous reconsideration of time derivatives in
Eulerian description shows that it evokes Minkowski metric for any flow field
domain without any previous postulation. Mathematical approach is developed
within the framework of congruences for general 4-dimensional differentiable
manifold and the final result is formulated in form of a theorem. A modified
version of the Convection Theorem provides a necessary cross-verification for a
reconsidered differential form of continuity equation. Although the approach is
developed for one-component (scalar) flow field, it can be easily generalized
to any tensor field. Some possible implications for classical electrodynamics
are also explored.


title: Femtosecond laser pulse induced Coulomb explosion

abstract:
  Coulomb explosion is revisited on the basis of explosion theory. The
characteristics of the Coulomb explosion such as the ion kinetic energy, the
energy distribution function, the laser absorption length along with the
neutron yield are determined. The model explains reasonably well the
experimental results.


title:
On Essential Incompleteness of Hertz's Experiments on Propagation of
  Electromagnetic Interactions

abstract:
  The historical background of the 19th century electromagnetic theory is
revisited from the standpoint of the opposition between alternative approaches
in respect to the problem of interactions. The 19th century electrodynamics
became the battle-field of a paramount importance to test existing conceptions
of interactions. Hertz's experiments were designed to bring a solid
experimental evidence in favor of one of them. The modern scientific method
applied to analyze Hertz's experimental approach as well as the analysis of his
laboratory notes, dairy and private letters show that Hertz's
"\textit{crucial}" experiments cannot be considered as conclusive at many
points as it is generally implied. We found that alternative Helmholtz's
electrodynamics did not contradict any of Hertz's experimental observations of
transverse components as Maxwell's theory predicted. Moreover, as we now know
from recently published Hertz's dairy and private notes, his first experimental
results indicated clearly on infinite rate of propagation. Nevertheless,
Hertz's experiments provided no further explicit information on non-local
longitudinal components which were such an essential feature of Helmholtz's
theory. Necessary and sufficient conditions for a decisive choice on the
adequate account of electromagnetic interactions are discussed from the
position of modern scientific method.


title: Johnson-Kendall-Roberts theory applied to living cells

abstract:
  Johnson-Kendall-Roberts (JKR) theory is an accurate model for strong adhesion
energies of soft slightly deformable material. Little is known about the
validity of this theory on complex systems such as living cells. We have
addressed this problem using a depletion controlled cell adhesion and measured
the force necessary to separate the cells with a micropipette technique. We
show that the cytoskeleton can provide the cells with a 3D structure that is
sufficiently elastic and has a sufficiently low deformability for JKR theory to
be valid. When the cytoskeleton is disrupted, JKR theory is no longer
applicable.


title: Coarse-graining protein energetics in sequence variables

abstract:
  We show that cluster expansions (CE), previously used to model solid-state
materials with binary or ternary configurational disorder, can be extended to
the protein design problem. We present a generalized CE framework, in which
properties such as energy can be unambiguously expanded in the amino-acid
sequence space. The CE coarse grains over nonsequence degrees of freedom (e.g.,
side-chain conformations) and thereby simplifies the problem of designing
proteins, or predicting the compatibility of a sequence with a given structure,
by many orders of magnitude. The CE is physically transparent, and can be
evaluated through linear regression on the energies of training sequences. We
show, as example, that good prediction accuracy is obtained with up to pairwise
interactions for a coiled-coil backbone, and that triplet interactions are
important in the energetics of a more globular zinc-finger backbone.


title: Two particle realisation of the Poincare group with interaction

abstract:
  A relative position 4-vector is constructed for two spin-zero particles. Some
advantages of this relative position over Bakamjian-Thomas are pointed out. The
centre-of-mass (CM) and relative positions and momenta are an explicit
realisation of the so-called non-canonical covariant representation. The
Hamiltonian including potential terms is factorised into CM and relative
components, the latter is a Lorentz scalar readily evaluated in the CM rest
frame when the relative position, momentum are canonical conjugates.

categories: physics.class-ph hep-th physics.gen-ph quant-ph


title: Statistical Mechanical Approach to Human Language

abstract:
  We use the formulation of equilibrium statistical mechanics in order to study
some important characteristics of language. Using a simple expression for the
Hamiltonian of a language system, which is directly implied by the Zipf law, we
are able to explain several characteristic features of human language that seem
completely unrelated, such as the universality of the Zipf exponent, the
vocabulary size of children, the reduced communication abilities of people
suffering from schizophrenia, etc. While several explanations are necessarily
only qualitative at this stage, we have, nevertheless, been able to derive a
formula for the vocabulary size of children as a function of age, which agrees
rather well with experimental data.


title:
Instantaneous versus non-instantaneous approach to relativistic
  ionization of atomic hydrogen by electron impact

abstract:
  We present a theoretical model for atomic hydrogen ionization by electron
impact in the instantaneous approximation and the more accurate
non-instantaneous approach using the methods of Quantum Electrodynamics, for
the binary coplanar and the coplanar asymmetric geometries. All electrons are
described by plane wave functions in the coplanar binary geometry but in the
asymmetric geometry the ejected electron is described by a Sommerfeld-Maue wave
function. It is shown that the two models give the same results in the non
relativistic limit for the binary coplanar geometry where the interactions can
be treated as instantaneous. However, this is no longer true for the
relativistic case where one has to take into account both the instantaneous
interaction and the radiation interaction. These results are obtained in the
first order of perturbation theory.


title:
Development of an Indium Bump Bond Process for Silicon Pixel Detectors
  at PSI

abstract:
  The hybrid pixel detectors used in the high energy physics experiments
currently under construction use a three dimensional connection technique, the
so-called bump bonding. As the pitch below 100um, required in these
applications, cannot be fullfilled with standard industrial processes (e.g. the
IBM C4 process), an in-house bump bond process using reflown indium bumps was
developed at PSI as part of the R&D for the CMS-pixel detector.
  The bump deposition on the sensor is performed in two subsequent lift-off
steps. As the first photolithographic step a thin under bump metalization (UBM)
is sputtered onto bump pads. It is wettable by indium and defines the diameter
of the bump. The indium is evaporated via a second photolithographic step with
larger openings and is reflown afterwards. The height of the balls is defined
by the volume of the indium. On the readout chip only one photolithographic
step is carried out to deposit the UBM and a thin indium layer for better
adhesion. After mating both parts a second reflow is performed for self
alignment and obtaining a high mechanical strength.
  For the placement of the chips a manual and an automatic machine was
constructed. The former is very flexible in handling different chip and module
geometries but has a limited throughput while the latter features a much higher
grade of automatisation and is therefore much more suited for producing
hundreds of modules with a well defined geometry.
  The reliability of this process was proven by the successful construction of
the PILATUS detector. The construction of PILATUS 6M (60 modules) and the CMS
pixel barrel (roughly 800 modules) will start in 2005.


title:
GPRD, A Database for the Spectral Properties of Diatomic Molecules of
  Atmospheric Interest

abstract:
  A short note describing the development of a database providing factual and
numerical data on the spectral properties of diatomic molecules. This database
is available online for the overall scientific community at the following
adress: http://cfp.ist.utl.pt/radiation/


title: Non-stationary Rayleigh-Taylor instability in supernovae ejecta

abstract:
  The Rayleigh-Taylor instability plays an important role in the dynamics of
several astronomical objects, in particular, in supernovae (SN) evolution. In
this paper we develop an analytical approach to study the stability analysis of
spherical expansion of the SN ejecta by using a special transformation in the
co-moving coordinate frame. We first study a non-stationary spherical expansion
of a gas shell under the pressure of a central source. Then we analyze its
stability with respect to a no radial, non spherically symmetric perturbation
of the of the shell. We consider the case where the polytropic constant of the
SN shell is $\gamma=5/3$ and we examine the evolution of a arbitrary shell
perturbation. The dispersion relation is derived. The growth rate of the
perturbation is found and its temporal and spatial evolution is discussed. The
stability domain depends on the ejecta shell thickness, its acceleration, and
the perturbation wavelength.


title:
Comment on Hartree Fock Roothaan Calculations for Ground States of Some
  Atoms Using Minimal Basis Sets of Integer and Noninteger n STOs

abstract:
  Recently published formulas for the one-center integrals arising in atomic
Hartree-Fock-Roothaan (HFR) calculations with noninteger n STOs (S.Gumus, T.
Ozdogan, Chin. J. Chem., 22 (2004) 1262) are critically analyzed. The purpose
of this note is to point out that the presented in these work relations for the
integer n -nuclear attraction and kinetic energy integrals which are available
in the literature (C.C.J. Roothaan, J. Chem. Phys., 19 (1951) 1445) can not be
used for noninteger STOs. In addition, the formulas for two-electron integrals
can be obtained from the published in the literature (T. Koga, K. Kanayama,
Chem.Phys.Let., 266(1997)123; I.I. Guseinov, B.A. Mamedov, Theor. Chem.
Acc.,108 (2002) 21) relations by changing the indices. It should be noted that
the accuracy of computer values for ground states energy of some closed and
open shell atoms in the case of noninteger n STOs is not guaranteed since the
calculations were performed by the use of integer n -one electron integrals. It
is argued that the paper sheds no new light on the subject and that it is
altogether misleading.


title: Excitation of wakefields in a plasma channel by a laser pulse

abstract:
  The excitation of wakefields by a triangular temporal profile laser pulse
with an abrupt fall in a step density profile plasma channel is investigated
analytically and an exact solution is obtained. The excitation is more
efficient for t~tp, where t is the rise time of the pulse and tp is the plasma
period, though it is still significant for t~20 tp. The wake potential in the
former case is 1.7 times the ponderomotive potential, whereas it falls to 1.4
times the ponderomotive potential for the latter.


title:
Natural configurations and normal frequencies of a vertically suspended,
  spinning, loaded chain with both extremities pinned

abstract:
  The resonant configurations and normal frequencies of a loaded hanging chain
that is rotating uniformly about the vertical are examined for theoretical and
experimental perspectives. The chain is assumed pinned at both ends, with an
extra load added to the lower end for stability. The equation of motion for
this system is solved and it is shown that the various resonant configurations
of the chain are described by Bessel functions of order zero. The normal
frequencies are obtained and the predictions of the model are compared to
experiment. Time-exposure photographs are presented to illustrate the shape of
the various normal modes.


title: Celebrating the Physics in Geophysics

abstract:
  As 2005, the International Year of Physics, comes to an end, two physicists
working primarily in geophysical research reflect on how geophysics is not an
applied physics. Although geophysics has certainly benefited from progress in
physics and sometimes emulated the reductionist program of mainstream physics,
it has also educated the physics community about some of the generic behaviors
of strongly nonlinear systems. Dramatic examples are the insights we have
gained into the ``emergent'' phenomena of chaos, cascading instabilities,
turbulence, self-organization, fractal structure, power-law variability,
anomalous scaling, threshold dynamics, creep, fracture, and so on. In all of
these examples, relatively simple models have been able to explain the
recurring features of apparently very complex signals and fields. It appears
that the future of the intricate relation between physics and geophysics will
be as exciting as its past has been characterized by a mutual fascination.
Physics departments in our universities should capitalize on this trend to
attract and retain young talent motivated to address problems that really
matter for the future of the planet. A pressing topic with huge impact on
populations and that is challenging enough for both physics and geophysics
communities to work together like never before is the understanding and
prediction of extreme events.


title: Financial Markets and Persistence

abstract:
  Persistence is studied in a financial context by mapping the time evolution
of the values of the shares quoted on the London Financial Times Stock Exchange
100 index (FTSE 100) onto Ising spins. By following the time dependence of the
spins, we find evidence for power law decay of the proportion of shares that
remain either above or below their ` starting\rq values. As a result, we
estimate a persistence exponent for the underlying financial market to be
$\theta_f\sim 0.5$.


title: Determining the Spectral Signature of Spatial Coherent Structures

abstract:
  We applied to an open flow a proper orthogonal decomposition (pod) technique,
on 2D snapshots of the instantaneous velocity field, to reveal the spatial
coherent structures responsible of the self-sustained oscillations observed in
the spectral distribution of time series. We applied the technique to 2D planes
out of 3D direct numerical simulations on an open cavity flow. The process can
easily be implemented on usual personal computers, and might bring deep
insights on the relation between spatial events and temporal signature in (both
numerical or experimental) open flows.