title: What is the Vortex Lattice Melting, Reality or Fiction?

abstract:
  This work fights against the widespread delusion cond-mat/0111052 on the
vortex lattice melting. In spite of the outward appearances the Abrikosov state
is not the vortex lattice with crystalline long-range order because pinning
disorders destroy this order in real superconductors (A.I.Larkin, 1970) and the
Abrikosov's solution 1957 year is not valid in the ideal case (K.Maki and
H.Takayama, 1972). Only long-range order - long-range phase coherence exists in
the Abrikosov state. Therefore the vortex lattice melting theories are science
fiction cond-mat/9811051. The phase transition interpreted erroneously as the
vortex lattice melting is in reality a disappearance of long-range phase
coherence. In spite of the widespread opinion these two transitions are
different transitions when a suitable definition of phase coherence is used.
The superconducting state without phase coherence differs in essence from the
mythical vortex liquid. The vortex, as a singularity in superconducting state
with phase coherence, can not exist without phase coherence.


title:
Low-energy muon-transfer reaction from hydrogen isotopes to helium
  isotopes

abstract:
  Direct muon transfer in low-energy collisions of the muonic hydrogen H$_\mu$
and helium (He$^{++}$) is considered in a three-body quantum-mechanical
framework of coordinate-space integro-differential Faddeev-Hahn-type equations
within two- and six-state close coupling approximations. The final-state
Coulomb interaction is treated without any approximation employing appropriate
Coulomb waves in the final state. The present results agree reasonably well
with previous semiclassical calculations.


title:
The Study of Complex Mechanical Oscillators using an Inexpensive
  Computer Acquisition and Processing System

abstract:
  An inexpensive analog-to-digital converter has been built around the game
port of the IBM personal computer. Using a single field effect transistor (FET)
and three carbon resistors, it allows the game card to measure voltage, instead
of its usual measurement of resistance. Since power for the FET is drawn from
the game port, the total cost of components, external to the computer, is very
low at about one U.S. dollar. The converter is linear enough for many
applications, and is presently used to study the complex free decay of a long
period physical pendulum. Software support is via QuickBasic, and the
hardware/software package design was influenced by a consideration of amateur
seismology needs.


title: A Note on "Extension, Spin and Non Commutativity"

abstract:
  We show that the Dirac theory of the electron, corresponds to recent
approaches based on a Non commutative spacetime.


title: Renormalization of QED in an external field

abstract:
  The Schwinger equations of QED are rewritten in three different ways as
integral equations involving functional derivatives, which are called weak
field, strong field, and SCF quantum electrodynamics. The perturbative
solutions of these equations are given in terms of appropriate Feynman
diagrams. The Green function that is used as an electron propagator in each
case is discussed in detail. The general renormalization rules for each of the
three equations are provided both in a non perturbative way (Dyson relations)
and for Feynman diagrams.


title: The control of phenotype: connecting enzyme variation to physiology

abstract:
  Metabolic control analysis (Kacser & Burns (1973). Symp. Soc. Exp. Biol. 27,
65-104; Heinrich & Rapoport (1974). Eur. J. Biochem. 42, 89-95) was developed
for the understanding of multi-enzyme networks. At the core of this approach is
the flux summation theorem. This theorem implies that there is an invariant
relationship between the control coefficients of enzymes in a pathway. One of
the main conclusions that has been derived from the summation theorem is that
phenotypic robustness to mutation (e.g. dominance) is an inherent property of
metabolic systems and hence does not require an evolutionary explanation
(Kacser & Burns (1981). Genetics. 97, 639-666; Porteous (1996). J. theor. Biol.
182, 223-232). Here we show that for mutations involving discrete changes (of
any magnitude) in enzyme concentration the flux summation theorem does not
hold. The scenarios we examine are two-enzyme pathways with a diffusion
barrier, two enzyme pathways that allow for enzyme saturation and two enzyme
pathways that have both saturable enzymes and a diffusion barrier. Our results
are extendable to sequential pathways with any number of enzymes. The fact that
the flux summation theorem cannot hold in sequential pathways casts serious
doubts on the claim that robustness with respect to mutations is an inherent
property of metabolic systems.


title:
Apparent suppression of turbulent magnetic dynamo action by a dc
  magnetic field

abstract:
  Numerical studies of the effect of a dc magnetic field on dynamo action
(development of magnetic fields with large spatial scales), due to
helically-driven magnetohydrodynamic turbulence, are reported. The apparent
effect of the dc magnetic field is to suppress the dynamo action, above a
relatively low threshold. However, the possibility that the suppression results
from an improper combination of rectangular triply spatially-periodic boundary
conditions and a uniform dc magnetic field is addressed: heretofore a common
and convenient computational convention in turbulence investigations. Physical
reasons for the observed suppression are suggested. Other geometries and
boundary conditions are offered for which the dynamo action is expected not to
be suppressed by the presence of a dc magnetic field component.


title: The Stationary Statistics of a Turbulent Environment as an Attractor

abstract:
  A proposal for a calculational program in fluid turbulence is presented. It
is proposed that the fluid probability density functional has an attractor for
its time-evolution, just as the dynamical system itself has. The evolution of
the fluid's statistics can be set up as a space-time path integral. Fluid
space-time configuration sampling techniques naturally suggest a useful way,
using an arbitrary initial statistics functional, to calculate averages.


title:
Einstein coefficients, cross sections, f values, dipole moments, and all
  that

abstract:
  The relationships among various parameters describing the strength of optical
transitions in atoms and molecules are reviewed. The application of these
parameters to the description of the interaction between nearly monochromatic,
directional light beams and atoms and molecules is given careful attention.
Common pitfalls in relating these parameters are pointed out. This is a revised
(February, 2002) version of a paper that originally appeared in Am. J. Phys.
50, 982-986 (1982).


title:
Remarks on the Physical Meaning of Diffraction-Free Solutions of Maxwell
  Equations

abstract:
  It is proved that a source of electromagnetic radiation cannot emit a
diffraction-free beam at the wave zone. A Bessel $J_0$ $\phi $-invariant beam
does not hold even at the intermediate zone. These results negate claims
published recently in the literature.


title:
The electromagnetic fields under, on and up Earth surface as earthquakes
  precursor in the Balkans and Black Sea regions

abstract:
  It is demonstrate that the analysis of accuracy measurement of geomagnetic
field and the behavior of local tide gravitational potential can serve as an
earthquake precursor


title: Global Optimization by Adiabatic Switching

abstract:
  We apply a recently introduced method for global optimization to determine
the ground state energy and configuration for model metallic clusters. The
global minimum for a given N-atom cluster is found by following the damped
dynamics of the N particle system on an evolving potential energy surface. In
this application, the time dependent interatomic potential interpolates
adiabatically between the Lennard-Jones (LJ) and the Sutton-Chen (SC) forms.
Starting with an ensemble of initial conditions corresponding to the ground
state configuration of the Lennard-Jones cluster, the system asymptotically
reaches the ground state of the Sutton-Chen cluster. We describe the method and
present results for specific cluster size N=15, when the ground state symmetry
of LJ$_N$ and SC$_N$ differ.


title: Strong-field terahertz-optical mixing in excitons

abstract:
  Driving a double-quantum-well excitonic intersubband resonance with a
terahertz (THz) electric field of frequency \omega_{THz} generated terahertz
optical sidebands \omega=\omega_{THz}+\omega_{NIR} on a weak NIR probe. At high
THz intensities, the intersubband dipole energy which coupled two excitons was
comparable to the THz photon energy. In this strong-field regime the sideband
intensity displayed a non-monotonic dependence on the THz field strength. The
oscillating refractive index which gives rise to the sidebands may be
understood by the formation of Floquet states, which oscillate with the same
periodicity as the driving THz field.


title: Solvation model dependency of helix-coil transition in polyalanine

abstract:
  Helix-coil transitions in poly-alanine molecules of length 10 are studied by
multicanonical Monte Carlo simulations. The solvation effects are included by
either a distance-dependent dielectric permittivity or by a term that is
proportional to the solvent-accessible surface area of the peptide. We found a
strong dependence of the characteristics of the helix-coil transition from the
details of the solvation model.


title: Spatio-temporal patterns in the Hantavirus infection

abstract:
  We present a model of the infection of Hantavirus in deer mouse, Peromyscus
maniculatus, based on biological observations of the system in the North
American Southwest. The results of the analysis shed light on relevant
observations of the biological system, such as the sporadical disappearance of
the infection, and the existence of foci or ``refugia'' that perform as
reservoirs of the virus when environmental conditions are less than optimal.

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


title: Continually Working Multiwire Porous Detectors of Radiation

abstract:
  Performance of the known porous multiwire radiation detectors is stable in
the mode of pulsed voltage supply. The results of the study of multiwire porous
detector operated at constant voltage supply are presented in this article. It
is shown that the detector's performance is stable, and its spatial resolution
$\Delta x \beta \pm 60 \mu m$.


title: Products of Random Matrices

abstract:
  We derive analytic expressions for infinite products of random 2x2 matrices.
The determinant of the target matrix is log-normally distributed, whereas the
remainder is a surprisingly complicated function of a parameter characterizing
the norm of the matrix and a parameter characterizing its skewness. The
distribution may have importance as an uncommitted prior in statistical image
analysis.


title: Study of Counting Characteristics of Porous Radiation Detectors

abstract:
  This paper presents the development of a new technology of registration of
ionizing radiation and a new type of detectors - single-cathode multiwire
porous detector with neither a gaseous nor semiconductor, but a porous
dielectric substance, e.g., CsI, being used as working medium. It is shown that
the performance of the multiwire porous detector is stable, ensuring highly
efficient detection of both heavily ionizing particles and soft X-rays with a
spatial resolution better than $\pm 60\mu m$. The continuous stable performance
opens up new perspectives for using porous detectors in research as well as
medicine. The obtained data are basic for the development of the theory of the
phenomenon of electrons' drift and multiplication in porous dielectrics under
the action of a strong external electric field.


title:
Microspectroscopy and Imaging in the THz Range Using Coherent CW
  Radiation

abstract:
  A novel THz near-field spectrometer is presented which allows to perform
biological and medical studies with high spectral resolution combined with a
spatial resolution down to l/100. In the setup an aperture much smaller than
the used wavelength is placed in the beam very close to the sample. The sample
is probed by the evanescent wave behind the aperture. The distance is measured
extremely accurate by a confocal microscope. We use monochromatic sources which
provide powerful coherent cw radiation tuneable from 50 GHz up to 1.5 THz.
Transmission and reflection experiments can be performed which enable us to
study solids and molecules in aqueous solution. Examples for spectroscopic
investigations on biological tissues are presented.


title:
Motion of particles in storage rings in the presence of a
  counterpropagating laser beam I

abstract:
  The dynamics of charged particle beams interacting with laser beams and
material targets in storage rings is presented. Formulas for the radiative
damping, quantum excitation and equilibrium parameters of ion and electron
beams determined by the backward rayleigh and backward compton scattering are
derived. General case is considered. It takes into account the possibility of
the periodical displacement of the laser beam in the radial direction with
varying velocity in the process of the interaction of the beams and includes
the possibility of the description of dynamics of muon beams interacting with
material targets in storage rings (enhanced ionization cooling). The example is
considered and some applications of being cooled beams are discussed.


title: Feshbach-Stimulated Photoproduction of a Stable Molecular Condensate

abstract:
  Photoassociation and the Feshbach resonance are, in principle, feasible means
for creating a molecular Bose-Einstein condensate from an
already-quantum-degenerate gas of atoms; however, mean-field shifts and
irreversible decay place practical constraints on the efficient delivery of
stable molecules using either mechanism alone. We therefore propose
Feshbach-stimulated Raman photoproduction, i.e., a combination of magnetic and
optical methods, as a viable means to collectively convert degenerate atoms
into a stable molecular condensate with near-unit efficiency.

categories: physics.atom-ph cond-mat.soft physics.chem-ph quant-ph


title:
New group structures for Carbon onions and Carbon nanotubes via affine
  extensions of non-crystallographic Coxeter groups

abstract:
  We present results underlining the conjecture that affine extensions for
non-crystallographic Coxeter groups are suitable mathematical objects for the
description of the symmetries of Carbon onions and Carbon nanotubes. It is the
hope that these considerations will shed new light on open questions concerning
structure, stability and formation of these fullerenes.


title:
Optical shielding of cold collisions in blue-detuned near-resonant
  optical lattices

abstract:
  We report Monte Carlo wave function simulation results for two colliding
atoms in a blue-detuned near-resonant $J=1\to J=1$ optical lattice. Our results
show that complete optical shielding of collisions can be achieved within the
lattice with suitably selected and realistic laser field parameters. More
importantly, our results demonstrate that the shielding effect does not
interfere with the actual trapping and cooling process, and it is produced by
the lattice lasers themselves, without the need to use additional laser beams.


title: On Apparent Superluminal Motion in Astrophysical Jet Models

abstract:
  Astrophysical models developed to explain superluminal motion in beaming
phenomena are shown to be incomplete and the correct kinematical expression in
any case to predict projected velocities slower than the speed of light. The
observed superluminal motions in the plane of the sky are proposed to be real.


title: Complex Response Function of Magnetic Resonance Spectrometers

abstract:
  A vectorial analysis of magnetic resonance spectrometers, based on traveling
wave resonators and including the reference arm and the automatic control of
frequency, has been developed. The proposed model, valid also for stationary
wave resonators, gives the response function of the spectrometer for any
working condition, including scalar detectors with arbitrary response law and
arbitrary excitation frequency. The purely dispersive and purely absorptive
linear responses are discussed in detail for different scalar detectors. The
developed approach allows for optimizing the performances of the spectrometer
and for obtaining the intrinsic lineshape of the sample in a very broad range
of working conditions. More complex setups can be modeled following the
proposed scheme.


title: Hanle effect in coherent backscattering

abstract:
  We study the shape of the coherent backscattering (CBS) cone obtained when
resonant light illuminates a thick cloud of laser-cooled rubidium atoms in
presence of a homogenous magnetic field. We observe new magnetic
field-dependent anisotropies in the CBS signal. We show that the observed
behavior is due to the modification of the atomic radiation pattern by the
magnetic field (Hanle effect in the excited state).


title:
Statistics of temperature fluctuations in a buoyancy dominated boundary
  layer flow simulated by a Large-eddy simulation model

abstract:
  Temperature fluctuations in an atmospheric convective boundary layer are
investigated by means of Large Eddy Simulations (LES). A statistical
characterization for both weak temperature fluctuations and strong temperature
fluctuations has been found. Despite the nontriviality of the dynamics of
temperature fluctuations, our data support the idea that the most relevant
statistical properties can be captured solely in terms of two scaling
exponents, characterizing the entire mixed layer. Such exponents control
asymptotic (i.e. core and tails) rescaling properties of the probability
density functions of equal-time temperature differences, $\Delta_r \theta$,
between points separated by a distance ${\bm r}$. A link between statistical
properties of large temperature fluctuations and geometrical properties of the
set hosting such fluctuations is also provided. Finally, a possible application
of our new findings to the problem of subgrid-scale parameterizations for the
temperature field in a convective boundary layer is discussed.


title: Optical chaos in nonlinear photonic crystals

abstract:
  We examine a spatial evolution of lightwaves in a nonlinear photonic crystal
with a quadratic nonlinearity when simultaneously a second harmonic and a
sum-frequency generation are quasi-phase-matched. We find the conditions of a
transition to Hamiltonian chaos for different amplitudes of lightwaves at the
boundary of the crystal.

categories: physics.optics cond-mat.stat-mech nlin.CD nlin.PS


title:
Toroidal configuration of the orbit of the electron of the hydrogen atom
  under strong external magnetic fields

abstract:
  In this paper we overview some results on the hydrogen atom in external
static uniform magnetic fields. We focus on the case of very strong magnetic
field, B>>B_0=2.3x10^9 Gauss, use various approximate models and, particularly,
in the adiabatic approximation have calculated exactly the integral defining
the effective potential. This potential appears to be finite at z=0. Our
consideration of the problem of highly magnetized atoms and molecules is
motivated by the recently developed MagneGas technology by Santilli
(http://www.magnegas.com). The ground state electron charge distribution of the
hydrogen atom in an intense magnetic field is of a toroidal form, in agreement
with that studied by Santilli. This physical picture is at the foundation of
the new chemical species of magnecules proposed by Santilli.


title: Laser Spinning of Nanotubes: A path to fast-rotating microdevices

abstract:
  We show that circularly polarized light can spin nanotubes with GHz
frequencies. In this method, angular moments of infrared photons are resonantly
transferred to nanotube phonons and passed to the tube body by "umklapp"
scattering. We investigate experimental realization of this ultrafast rotation
in carbon nanotubes, levitating in an optical trap and undergoing mechanical
vibrations, and discuss possible applications to rotating microdevices.


title: Transparency of Magnetized Plasma at Cyclotron Frequency

abstract:
  Electromagnetic radiation is strongly absorbed by the magnetized plasma if
its frequency equals the cyclotron frequency of plasma electrons. It is
demonstrated that absorption can be completely canceled in the presence of a
second radiation beam, or even a magnetostatic field of an undulator, resulting
in plasma transparency at the cyclotron frequency. This effect is reminiscent
of the electromagnetically-induced transparency (EIT) of the three-level atomic
systems, except that it occurs in a completely {\it classical} plasma. Also,
because of the complexity of the classical plasma, index of refraction at
cyclotron frequency differs from unity. Potential applications of the EIT in
plasma include selective plasma heating, electromagnetic control of the index
of refraction, and electron/ion acceleration.


title:
A case study of the mid-latitude GPS performance at nighttime during the
  magnetic storm of July 15, 2000

abstract:
  Using the geomagnetic storm of July 15, 2000 as an example, we investigated
the dependence of GPS navigation system performance on the nightside at
mid-latitudes on the level of geomagnetic disturbance. The investigation was
based on the data from the global GPS system available through the Internet. It
was shown that the number of GPS phase slips increases with the increasing
level of disturbance and that there is a good correlation between the rate of
Dst-variation and the frequency of slips. It was further shown that the
relative frequency of slips has also a clearly pronounced aspect dependence.
Phase slips of the GPS signal can be caused by the scattering from small-scale
irregularities of the ionospheric E-layer. Phase slip characteristics are
indicative of Farley-Buneman instabilities as a plausible physical mechanism
that is responsible for the formation of geomagnetic field-aligned
irregularities. Using simultaneous measurements of backscatter signal
characteristics from the Irkutsk incoherent scatter radar and existing models
for such irregularities, we estimated the order of magnitude of the expected
phase fluctuations of the GPS signal at a few degrees.


title: A geometrical setting for the classification of multilayers

abstract:
  We elaborate on the consequences of the factorization of the transfer matrix
of any lossless multilayer in terms of three basic matrices of simple
interpretation. By considering the bilinear transformation that this transfer
matrix induces in the complex plane, we introduce the concept of multilayer
transfer function and study its properties in the unit disk. In this
geometrical setting, our factorization translates into three actions that can
be viewed as the basic pieces for understanding the multilayer behavior.
Additionally, we introduce a simple trace criterion that allows us to classify
multilayers in three types with properties closely related to one (and only
one) of these three basic matrices. We apply this approach to analyze some
practical examples that are representative of these types of matrices.


title:
Superradiance on the Landau levels and the problem of power of decameter
  radiation of Jupiter

abstract:
  We determine the conditions of formation of spontaneous polarization phase
transition to the superradiance regime in the inverted system of
nonrelativistic electrons on equidistant Landau levels in rarefied magnetized
plasma. The possibility of realization of such conditions in the lower Jupiter
magnetosphere is shown. The effect of cyclotron superradiance on the Landau
levels gives a key to interpretation of the nature of superpower radioemission
of the Jupiter-Io system.


title:
Strong field approximation to the relativistic channeling of electrons
  in the presence of electromagnetic waves

abstract:
  We present a study of the interaction of a relativistically planar channeled
electron with an intense electromagnetic field. Using a S-Matrix approach in
the Strong Field Approximation, it is shown that the crystal periodicity
affects drastically the excitation process, suppressing the possibility of
multiphoton absorption except for some particular cases. This selective
excitation opens the possibility to control the dynamics of the channeling
process by means of an external field. Explicit expressions for the S-matrix
N-photon excitation rates together with the corresponding conservation laws are
obtained from the relativistic quantum mechanical Dirac equation.


title:
Translocation Properties of Primitive Molecular Machines and Their
  Relevance to the Structure of the Genetic Code

abstract:
  We address the question, related with the origin of the genetic code, of why
are there three bases per codon in the translation to protein process. As a
followup to our previous work, we approach this problem by considering the
translocation properties of primitive molecular machines, which capture basic
features of ribosomal/messenger RNA interactions, while operating under
prebiotic conditions. Our model consists of a short one-dimensional chain of
charged particles(rRNA antecedent) interacting with a polymer (mRNA antecedent)
via electrostatic forces. The chain is subject to external forcing that causes
it to move along the polymer which is fixed in a quasi one dimensional
geometry. Our numerical and analytic studies of statistical properties of
random chain/polymer potentials suggest that, under very general conditions, a
dynamics is attained in which the chain moves along the polymer in steps of
three monomers. By adjusting the model in order to consider present day genetic
sequences, we show that the above property is enhanced for coding regions.
Intergenic sequences display a behavior closer to the random situation. We
argue that this dynamical property could be one of the underlying causes for
the three base codon structure of the genetic code.


title: Non-invasive single-bunch matching and emittance monitor

abstract:
  On-line monitoring of beam quality for high brightness beams is only possible
using non-invasive instruments. For matching measurements, very few such
instruments are available. One candidate is a quadrupole pick-up. Therefore, a
new type of quadrupole pick-up has been developed for the 26 GeV Proton
Synchrotron (PS) at CERN, and a measurement system consisting of two such
pick-ups is now installed in this accelerator. Using the information from these
pick-ups, it is possible to determine both injection matching and emittance in
the horizontal and vertical planes, for each bunch separately. This paper
presents the measurement method and some of the results from the first year of
use, as well as comparisons with other measurement methods.


title:
Experimental evidence that the gravitational constant varies with
  orientation

abstract:
  In 1687, Isaac Newton published the universal law of gravitation stating that
two bodies attract each other with a force proportional to the product of their
masses and the inverse square of the distance. The constant of proportionality,
G, is one of the fundamental constants of nature. As the precision of
measurements increased the disparity between the values of G, gathered by
different groups, surprisingly increased. This unique situation was reflected
by the 1998 CODATA decision to increase the relative G uncertainty from 0.013%
to 0.15 %. Our repetitive measurements of the gravitational constant (G) show
that G varies significantly with the orientation of the test masses relative to
the system of fixed stars, as was predicted by the Attractive Universe Theory.
The distances between the test masses were in the decimeter range. We have
observed that G changes with the orientation by at least 0.054%.


title: Specular reflection of matter waves from a rough mirror

abstract:
  We have made a high resolution study of the specularity of the atomic
reflection from an evanescent wave mirror using velocity selective Raman
transitions. We have observed a double structure in the velocity distribution
after reflection: a peak consistent with specular reflection and a diffuse
reflection pedestal, whose contribution decreases rapidly with increasing
detuning. The diffuse reflection is due to two distinct effects: spontaneous
emission in the evanescent wave and a roughness in the evanescent wave
potential whose amplitude is smaller than the de Broglie wavelength of the
reflected atoms.


title: Three particles in an external trap: Nature of the complete J=0 spectrum

abstract:
  Three bosonic, spin-polarized atoms in a spherical oscillator potential
constitutes the simplest nontrivial Bose-Einstein condensate (BEC). The present
paper develops the tools needed to understand the nature of the complete J=0
energy spectrum for this prototype system, assuming a sum of two-body
potentials. The resulting spectrum is calculated as a function of the two-body
scattering length a_sc, which documents the evolution of certain many-body
levels that evolve from BEC-type to molecular-type as the scattering length is
decreased. Implications for the behavior of the condensate excited-state
spectrum and for condensate formation and decay are elucidated. The energy
levels evolve smoothly, even through the regime where the number of two-body
bound states N_b increases by 1, and a_{sc} switches from -infinity to
infinity. We point out the possibility of suppressing three-body recombination
by tuning the two-body scattering length to values that are larger than the
size of the condensate ground state. Comparisons with mean-field treatments are
presented.


title: Concerning Hertz' photoelectric effect

abstract:
  Experimental evidence of the photoelectric effect goes back to H. Hertz. It
occurred during the famous confirmation experiments of the Maxwellian theory.
It is commonly held however that it cannot be explained in the framework of
that theory. We are calling attention to some aspects linked with the
interpretation of that effect on which, in our opinion, it is worthwhile
reflecting.


title:
Parallel algorithm with spectral convergence for nonlinear
  integro-differential equations

abstract:
  We discuss a numerical algorithm for solving nonlinear integro-differential
equations, and illustrate our findings for the particular case of Volterra type
equations. The algorithm combines a perturbation approach meant to render a
linearized version of the problem and a spectral method where unknown functions
are expanded in terms of Chebyshev polynomials (El-gendi's method). This
approach is shown to be suitable for the calculation of two-point Green
functions required in next to leading order studies of time-dependent quantum
field theory.


title:
How to Commission, Operate and Maintain a Large Future Accelerator
  Complex From Far Remote Sites

abstract:
  A study on future large accelerators [1] has considered a facility, which is
designed, built and operated by a worldwide collaboration of equal partner
institutions, and which is remote from most of these institutions. The full
range of operation was considered including commissioning, machine development,
maintenance, troubleshooting and repair. Experience from existing accelerators
confirms that most of these activities are already performed 'remotely'. The
large high-energy physics experiments and astronomy projects, already involve
international collaborations of distant institutions. Based on this experience,
the prospects for a machine operated remotely from far sites are encouraging.
Experts from each laboratory would remain at their home institution but
continue to participate in the operation of the machine after construction.
Experts are required to be on site only during initial commissioning and for
particularly difficult problems. Repairs require an on-site non-expert
maintenance crew. Most of the interventions can be made without an expert and
many of the rest resolved with remote assistance. There appears to be no
technical obstacle to controlling an accelerator from a distance. The major
challenge is to solve the complex management and communication problems.


title:
The influence of the spin-flip transitions on the photon spectrum from
  ultra-relatiovistic electrons in the field of a crystal

abstract:
  We investigate the influence of the spin-flip transitions on formation of the
spectral distribution of the radiation emitted by tens to hundreds GeV
ultrarelativistic electrons incident along crystallographic axis in a thin
single crystal. Both the formalism and the numerical data are presented. The
calculated spectra for 35 to 243 GeV electrons in W crystal are compared with
the dependences obtained experimentally (Kirshenbom K et al 2001 Phys.Rev.Lett
87 054801).


title: Relativistic motions

abstract:
  A physical consequence of a well-known Fermi's theorem: no motion of masses
can generate gravitational waves.


title: Formalism for Multiphoton Plasmon Excitation in Jellium Clusters

abstract:
  We present a new formalism for the description of multiphoton plasmon
excitation processes in jellium clusters. By using our method, we demonstrate
that, in addition to dipole plasmon excitations, the multipole plasmons
(quadrupole, octupole, etc) can be excited in a cluster by multiphoton
absorption processes, which results in a significant difference between plasmon
resonance profiles in the cross sections for multiphoton as compared to
single-photon absorption. We calculate the cross sections for multiphoton
absorption and analyse the balance between the surface and volume plasmon
contributions to multipole plasmons.


title:
Brillouin propagation modes in optical lattices: interpretation in terms
  of nonconventional stochastic resonance

abstract:
  We report the first direct observation of Brillouin-like propagation modes in
a dissipative periodic optical lattice. This has been done by observing, in
both theoretical and experimental work, a resonant behaviour of the spatial
diffusion coefficient in the direction corresponding to the propagation mode
with the phase velocity of the moving intensity modulation used to excite these
propagation modes. Furthermore, we show theoretically that the amplitude of the
Brillouin mode is a nonmonotonic function of the strength of the noise
corresponding to the optical pumping, and discuss this behaviour in terms of
nonconventional stochastic resonance.


title:
Pattern Propagation Speed in Synfire Chains with Excitatory-Inhibitory
  Couplings

abstract:
  The speed of firing pattern propagation in a synfire chain, composed of
non-leaky integrate-and-fire neurons, and assuming homogenous connection
delays, is studied. An explicit relation, relating the propagation speed to the
connecting weights distribution and other network parameters, is derived. The
analytic results are then checked with a computer simulation. When the network
is fed with a fully synchronized input pattern, the pattern propagation speed
is independent of the weight parameters. When the fed input is asynchronous,
depending on the weight parameters, the propagation speed is more than or less
than the synchronous case. In this case the propagation speed increases by
increasing the mean or standard deviation of connecting weights. The biological
relevance of these findings and their relevance to the notion of synfire chains
are discussed.


title:
Pulsed light beams in vacuum with superluminal and negative group
  velocities

abstract:
  Gouy's phase of transversally limited pulses can create a strong anomalous
dispersion in vacuum leading to highly superluminal and negative group
velocities. As a consequence, a focusing pulse can diverge beyond the focus
before converging into it. A simple experiment is proposed.


title: Multifractal detrended fluctuation analysis of nonstationary time series

abstract:
  We develop a method for the multifractal characterization of nonstationary
time series, which is based on a generalization of the detrended fluctuation
analysis (DFA). We relate our multifractal DFA method to the standard partition
function-based multifractal formalism, and prove that both approaches are
equivalent for stationary signals with compact support. By analyzing several
examples we show that the new method can reliably determine the multifractal
scaling behavior of time series. By comparing the multifractal DFA results for
original series to those for shuffled series we can distinguish multifractality
due to long-range correlations from multifractality due to a broad probability
density function. We also compare our results with the wavelet transform
modulus maxima (WTMM) method, and show that the results are equivalent.


title: Nonlinear magneto-optical rotation in optically thick media

abstract:
  Nonlinear magneto-optical rotation is a sensitive technique for measuring
magnetic fields. Here, the shot-noise-limited magnetometric sensitivity is
analyzed for the case of optically-thick media and high light power, which has
been the subject of recent experimental and theoretical investigations.


title:
Estimating the contribution from different ionospheric regions to the
  TEC response to the solar flares using data from the international GPS
  network

abstract:
  This paper proposes a new method for estimating the contribution from
different ionospheric regions to the response of total electron content
variations to the solar flare which uses the effect of partial shadowing of the
atmosphere by the terrestrial globe. The study uses GPS stations located near
the boundary of the shadow on the ground in the nightside hemisphere. The beams
between the satellite-borne transmitter and the receiver on the ground for
these stations pass partially through the atmosphere lying in the region of
total shadow and partially through the illuminated atmosphere. The analysis of
the ionospheric effect of a powerful solar flare of class X5.7/3B that was
recorded on July 14,
  2000 (10:24 UT, N22W07) in quiet geomagnetic conditions (Dst=-10 nT) has
shown that about 20% of the TEC increase correspond to the ionospheric region
lying below 100 km, about 5% refer to the ionospheric E-region (100-140 km),
about 30% correspond to the F1-region (140-200 km), and about 30% to regions
lying above 300 km.


title: Numerical Aperture of Single-Mode Photonic Crystal Fibers

abstract:
  We consider the problem of radiation into free space from the end-facet of a
single-mode photonic crystal fiber (PCF). We calculate the numerical aperture
NA=sin theta from the half-divergence angle theta ~ tan^{-1}(lambda/pi w) with
pi w^2 being the effective area of the mode in the PCF. For the fiber first
presented by Knight et al. we find a numerical aperture NA ~ 0.07 which
compares to standard fiber technology. We also study the effect of different
hole sizes and demonstrate that the PCF technology provides a large freedom for
NA-engineering. Comparing to experiments we find good agreement.


title: Globally-Linked Vortex Clusters in Trapped Wave Fields

abstract:
  We put forward the existence of a rich variety of fully stationary vortex
structures, termed H-clusters, made of an increasing number of vortices nested
in paraxial wave fields confined by trapping potentials. However, we show that
the constituent vortices are globally linked, rather than products of
independent vortices. Also, they always feature a monopolar global wave front
and exist in nonlinear systems, such as Bose-Einstein condensates. Clusters
with multipolar global wave fronts are non-stationary or at best flipping.


title: Long range correlations in DNA sequences

abstract:
  The so called long range correlation properties of DNA sequences are studied
using the variance analyses of the density distribution of a single or a group
of nucleotides in a model independent way. This new method which was suggested
earlier has been applied to extract slope parameters that characterize the
correlation properties for several intron containing and intron less DNA
sequences. An important aspect of all the DNA sequences is the properties of
complimentarity by virtue of which any two complimentary distributions (like GA
is complimentary to TC or G is complimentary to ATC) have identical
fluctuations at all scales although their distribution functions need not be
identical. Due to this complimentarity, the famous DNA walk representation
whose statistical interpretation is still unresolved is shown to be a special
case of the present formalism with a density distribution corresponding to a
purine or a pyrimidine group. Another interesting aspect of most of the DNA
sequences is that the factorial moments as a function of length exceed unity
around a region where the variance versus length in a log-log plot shows a
bending. This is a pure phenomenological observation which is found for several
DNA sequences with a few exception. Therefore, this length scale has been used
as an approximate measure to exclude the bending regions from the slope
analyses. The asymmetries in the nucleotide contents or the patchy structure as
a possible origin of the long range correlations has also been investigated.


title: Sur la solution de Sundman du probleme des trois corps

abstract:
  In contrast to a widely held opinion, the three-body problem has an analytic
solution. This solution was found in 1909 by Sundman. The basic ideas behind it
and its history are presented.
  -----
  Contrairement \`a une opinion largement r\'epandue, le probl\`eme des trois
corps poss\`ede une solution analytique. Cette solution fut d\'ecouverte en
1909 par Sundman. Nous pr\'esentons dans cet article les id\'ees de base et
l'histoire de cette solution.
  -----
  Entgegen einer weitverbreiteten Meinung ist das Dreik\"orperproblem
analytisch l\"osbar. Diese L\"osung wurde 1909 von Sundman gefunden. Die ihr
zugrundeliegenden Ideen und ihre Geschichte werden in einfacher Form
dargestellt.

categories: physics.hist-ph cond-mat math-ph math.HO math.MP


title: Finding an Upper Limit in the Presence of Unknown Background

abstract:
  Experimenters report an upper limit if the signal they are trying to detect
is non-existent or below their experiment's sensitivity. Such experiments may
be contaminated with a background too poorly understood to subtract. If the
background is distributed differently in some parameter from the expected
signal, it is possible to take advantage of this difference to get a stronger
limit than would be possible if the difference in distribution were ignored. We
discuss the ``Maximum Gap'' method, which finds the best gap between events for
setting an upper limit, and generalize to ``Optimum Interval'' methods, which
use intervals with especially few events. These methods, which apply to the
case of relatively small backgrounds, do not use binning, are relatively
insensitive to cuts on the range of the parameter, are parameter independent
(i.e., do not change when a one-one change of variables is made), and provide
true, though possibly conservative, classical one-sided confidence intervals.


title: An Analytical Formulation of CPMAS

abstract:
  An exact expression for the cross polarization between two spin-1/2 particles
is derived from the quantum Liouville equation. This is given in the form of
two integrodifferential equations. These can be solved exactly in the static
case (no sample spinning) and a powder average performed numerically. With
magic angle spinning, the neglect of certain interference terms simplifies the
numerical calculation. A further assumption decoupling the calculation of the
sidebands gives a very simple formula that is capable of giving a qualitative
interpretation of all experimental observations. Examples are given
illustrating typical buildup curves and CPMAS matching profiles.


title: The Relativistic World: A common sense perspective

abstract:
  The motivation for relativistic world is built on robust common sense and on
general physical principles which are accessible to even a school student.
Author likes to call it a farmer's perspective.


Comment on "Indispensable Finite Time Correlations for Fokker-Planck
  Equations from Time Series Data"


title: Quantum Finance

abstract:
  Quantum theory is used to model secondary financial markets. Contrary to
stochastic descriptions, the formalism emphasizes the importance of trading in
determining the value of a security. All possible realizations of investors
holding securities and cash is taken as the basis of the Hilbert space of
market states. The temporal evolution of an isolated market is unitary in this
space. Linear operators representing basic financial transactions such as cash
transfer and the buying or selling of securities are constructed and simple
model Hamiltonians that generate the temporal evolution due to cash flows and
the trading of securities are proposed. The Hamiltonian describing financial
transactions becomes local when the profit/loss from trading is small compared
to the turnover. This approximation may describe a highly liquid and efficient
stock market. The lognormal probability distribution for the price of a stock
with a variance that is proportional to the elapsed time is reproduced for an
equilibrium market. The asymptotic volatility of a stock in this case is
related to the long-term probability that it is traded.

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


title:
FAST CARS: Engineering a Laser Spectroscopic Technique for Rapid
  Identification of Bacterial Spores

abstract:
  Airborne contaminants, e.g., bacterial spores, are usually analyzed by time
consuming microscopic, chemical and biological assays. Current research into
real time laser spectroscopic detectors of such contaminants is based on e.g.
resonant Raman spectroscopy. The present approach derives from recent
experiments in which atoms and molecules are prepared by one (or more) coherent
laser(s) and probed by another set of lasers. The connection with previous
studies based on "Coherent Anti-Stokes Raman Spectroscopy" (CARS) is to be
noted. However generating and utilizing maximally coherent oscillation in
macromolecules having an enormous number of degrees of freedom is much more
challenging. This extension of the CARS technique is called FAST CARS
(Femtosecond Adaptive Spectroscopic Techniques for Coherent Anti-Stokes Raman
Spectroscopy), and the present paper proposes and analyses ways in which it
could be used to rapidly identify pre-selected molecules in real time.

categories: physics.optics physics.bio-ph physics.ins-det q-bio


title: Glory Oscillations in the Index of Refraction for Matter-Waves

abstract:
  We have measured the index of refraction for sodium de Broglie waves in gases
of Ar, Kr, Xe, and nitrogen over a wide range of sodium velocities. We observe
glory oscillations -- a velocity-dependent oscillation in the forward
scattering amplitude. An atom interferometer was used to observe glory
oscillations in the phase shift caused by the collision, which are larger than
glory oscillations observed in the cross section. The glory oscillations depend
sensitively on the shape of the interatomic potential, allowing us to
discriminate among various predictions for these potentials, none of which
completely agrees with our measurements.


title:
Study On Planar Whispering Gallery Dielectric Resonators. I. General
  Properties

abstract:
  Several basic properties of homogeneous planar Whispering Gallery dielectric
resonators are investigated through a general approach. In particular the
values for the minimum and maximum allowed radius, defined by irradiation and
dielectric losses, respectively, are obtained in terms of the complex
dielectric constant of the involved media. The same approach is employed in the
analysis of the limit allowed frequencies of a fixed family of mode, leading to
the definition of the "ideal" frequency band. The role of the transverse mode
is then discussed, and the "effective" frequency band is introduced and
determined both in simple disc and circular ring resonators. The extension of
the effective band is limited at least by a factor 3, in terms of decades, in
comparison to the extension of the ideal one; this limitation, due to the
presence of transverse modes, can be overcome using suitably designed
non-homogeneous resonators, as discussed in a following companion paper.


title:
Study On Planar Whispering Gallery Dielectric Resonators. II. A
  Multiple-Band Device

abstract:
  The basic theory underlying the realization of simple multiple-band
non-homogeneous dielectric resonators, whose spectral response is the overlap
of single-resonator frequency bands, is developed exploiting a general approach
discussed in the previous companion paper. The limit frequencies of the
proposed devices, given only by the dielectric properties of the involved
materials, can differ in principle by several decades. Experimental
confirmations have been obtained on a composite structure built up with teflon
and polyethylene; as predicted by the theory, the overall band includes
frequencies which range about from 20 GHz to more than 400 GHz, when high
frequency resonances are selectively excited. The localization of the higher
frequency radiation between the positive steps of the dielectric constant,
which is the basic properties of these non-homogeneous resonators, has been
experimentally verified by mapping the electromagnetic field intensity.
Possible applications of multiple-band Whispering Gallery dielectric resonators
are finally outlined.


title: Detection of Scintillation Light of Liquid Xenon with a LAAPD

abstract:
  First observation of liquid xenon scintillation due to alpha-particles and
gamma-rays with a large area avalanche photodiode immersed in the liquid is
reported. An energy resolution of 10% (FWHM) and a coincidence time resolution
of less then 1 ns (FWHM) were measured with 5.5 MeV alpha-particles and 511 keV
gamma-rays, respectively. The quantum efficiency of the photodiode for xenon
scintillation light (wavelength 178 nm) is estimated to be ~100%.


title:
Efficient implementation of the Projection Operator Imaginary Time
  Spectral Evolution (POITSE) method for excited states

abstract:
  We describe and systematically analyze new implementations of the Projection
Operator Imaginary Time Spectral Evolution (POITSE) method for the Monte Carlo
evaluation of excited state energies. The POITSE method involves the
computation of a correlation function in imaginary time. Decay of this function
contains information about excitation energies, which can be extracted by a
spectral transform. By incorporating branching processes in the Monte Carlo
propagation, we compute these correlation functions with significantly reduced
statistical noise. Our approach allows for the stable evaluation of small
energy differences in situations where the previous POITSE implementation was
limited by this noise.


title:
Correlating overrepresented upstream motifs to gene expression: a
  computational approach to regulatory element discovery in eukaryotes

abstract:
  Gene regulation in eukaryotes is mainly effected through transcription
factors binding to rather short recognition motifs generally located upstream
of the coding region. We present a novel computational method to identify
regulatory elements in the upstream region of eukaryotic genes. The genes are
grouped in sets sharing an overrepresented short motif in their upstream
sequence. For each set, the average expression level from a microarray
experiment is determined: If this level is significantly higher or lower than
the average taken over the whole genome, then the overerpresented motif shared
by the genes in the set is likely to play a role in their regulation. The
method was tested by applying it to the genome of Saccharomyces cerevisiae,
using the publicly available results of a DNA microarray experiment, in which
expression levels for virtually all the genes were measured during the diauxic
shift from fermentation to respiration. Several known motifs were correctly
identified, and a new candidate regulatory sequence was determined.


title: Presynaptic calcium dynamics of learning neurons

abstract:
  We present a new model for the dynamics of the presynaptic intracellular
calcium concentration in neurons evoked by various stimulation protocols. The
aim of the model is twofold: We want to discuss the calcium transients during
and after specific stimulation protocols as they are used to induce
long-term-depression and long-term-potentiation. In addition we would like to
provide a general tool which allows the comparison of different calcium
experiments. This may help to draw conclusions on a wider base in future.


title:
Statistical Geometry of Packing Defects of Lattice Chain Polymer from
  Enumeration and Sequential Monte Carlo Method

abstract:
  Voids exist in proteins as packing defects and are often associated with
protein functions. We study the statistical geometry of voids in
two-dimensional lattice chain polymers. We define voids as topological features
and develop a simple algorithm for their detection. For short chains, void
geometry is examined by enumerating all conformations. For long chains, the
space of void geometry is explored using sequential Monte Carlo importance
sampling and resampling techniques. We characterize the relationship of
geometric properties of voids with chain length, including probability of void
formation, expected number of voids, void size, and wall size of voids. We
formalize the concept of packing density for lattice polymers, and further
study the relationship between packing density and compactness, two parameters
frequently used to describe protein packing. We find that both fully extended
and maximally compact polymers have the highest packing density, but polymers
with intermediate compactness have low packing density. To study the
conformational entropic effects of void formation, we characterize the
conformation reduction factor of void formation and found that there are strong
end-effect. Voids are more likely to form at the chain end. The critical
exponent of end-effect is twice as large as that of self-contacting loop
formation when existence of voids is not required. We also briefly discuss the
sequential Monte Carlo sampling and resampling techniques used in this study.

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


title: On the Nature of the El Nino/La Nina Events

abstract:
  We propose a scenario that explains many of the Pacific Ocean climate
phenomena that are called El Nino/ La Nina. This scenario requires an event,
which we call a Super-Nino Event. It dominates other phenomena when it occurs.
A template of this event has been constructed giving the time evolution, which
is an alternating sequence of 'El Ninos' and 'La Ninas'. The duration of the
event is about 15 years unless some other event intervenes. Three such events
can explain most of the El Nino/La Nina features that have been observed since
1968. We find that the various El Nino/La Nina features that have been observed
fall into types, associated with the oscillation in the template, which can be
classified by a "Periodic Table". The Earth is presently experiencing one of
these events which started in the mid 1990's and will continue for another 4-5
years. This extrapolation into the future suggests that a minor El Nino will
begin in mid 2001 and will reach a maximum about a year later. The conditions
under which such a Super Nino-Event may occur are discussed.


title:
Field Transformation in the Extended Space Model: Prediction and
  Experimental Test

abstract:
  A run of preliminary experiments was carried out to check the prediction of
possible gravitational field generation process arising by stopping of charged
massive particles in a substance predicted by the recently developed Extended
Space Model (ESM).


title: Muon Energy Estimate Through Multiple Scattering with the Macro Detector

abstract:
  Muon energy measurement represents an important issue for any experiment
addressing neutrino induced upgoing muon studies. Since the neutrino
oscillation probability depends on the neutrino energy, a measurement of the
muon energy adds an important piece of information concerning the neutrino
system. We show in this paper how the MACRO limited streamer tube system can be
operated in drift mode by using the TDC's included in the QTPs, an electronics
designed for magnetic monopole search. An improvement of the space resolution
is obtained, through an analysis of the multiple scattering of muon tracks as
they pass through our detector. This information can be used further to obtain
an estimate of the energy of muons crossing the detector. Here we present the
results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines,
to provide a full check of the electronics and to exploit the feasibility of
such a multiple scattering analysis. We show that by using a neural network
approach, we are able to reconstruct the muon energy for $E_\mu<$40 GeV. The
test beam data provide an absolute energy calibration, which allows us to apply
this method to MACRO data.


title: Scissors modes in triaxial metal clusters

abstract:
  We study the scissors mode (orbital M1 excitations) in small Na clusters,
triaxial metal clusters ${\rm Na}_{12}$ and ${\rm Na}_{16}$ and the
close-to-spherical ${{\rm Na}_9}^+$, all described in DFT with detailed ionic
background. The scissors modes built on spin-saturated ground and
spin-polarized isomeric states are analyzed in virtue of both macroscopic
collective and microscopic shell-model treatments. It is shown that the mutual
destruction of Coulomb and the exchange-correlation parts of the residual
interaction makes the collective shift small and the net effect can depend on
details of the actual excited state. The crosstalk with dipole and spin-dipole
modes is studied in detail. In particular, a strong crosstalk with spin-dipole
negative-parity mode is found in the case of spin-polarized states. Triaxiality
and ionic structure considerably complicate the scissors response, mainly at
expense of stronger fragmentation of the strength. Nevertheless, even in these
complicated cases the scissors mode is mainly determined by the global
deformation. The detailed ionic structure destroys the spherical symmetry and
can cause finite M1 response (transverse optical mode) even in clusters with
zero global deformation. But its strength turns out to be much smaller than for
the genuine scissors modes in deformed systems.


title: Consciousness in Physics

abstract:
  This essay discusses the idea that a Theory of Everything would not be
complete without a theory of consciousness as one of its parts, and the
suggestion that new physics may be needed to describe consciousness. I argue
that the motivations behind searching for such a theory arise as the result of
misunderstandings over the use of language when talking about consciousness.


title:
A mathematical model for the germinal center morphology and affinity
  maturation

abstract:
  During germinal center reactions the appearance of two specific zones is
observed: the dark and the light zone. Up to now, the origin and function of
these zones are poorly understood. In the framework of a stochastic and
discrete model several possible pathways of zone development during germinal
center reactions are investigated. The importance of the zones in the germinal
center for affinity maturation, i.e. the process of antibody optimization is
discussed.


title:
Structure and mobility of cyclohexane as a solvent for
  Trans-Polyisoprene

abstract:
  Solutions of {\it trans}$-$polyisoprene in cyclohexane are investigated in
atomistic detail at different compositions at two different temperatures. We
investigate the influence of polymer concentration on the dynamics of the
solvent molecules and the structure of the solvation shell. The double bonds
along the polymer backbone are preferentially approached by the solvent
molecules. The mobility of cyclohexane molecules decreases with increasing
polymer concentration at ambient conditions. The reorientation of molecules
becomes more anisotropic with concentration as the polymer hinders the
reorientation of the molecular plane. At elevated temperatures the influence of
the polymer is weaker and the reorientation of the solvent is more isotropic.
Additionally, a fast and efficient way to set up atomistic simulations is shown
in detail in which the initial simulations increase in length and in the
simulation time-step. The excess energy from initial overlaps is removed by
resetting the velocities at regular intervals.


title:
Symmetry Analysis of ZnSe(100) Surface in Air By Second Harmonic
  Generation

abstract:
  Polarized and azimuthal dependencies of optical second harmonics generation
(SHG) at the surface of noncentrosymmetric semiconductor crystals have been
measured on polished surfaces of ZnSe(100), using a fundamental wavelength of
1.06$\mu m$. The SHG intensity patterns were analyzed for all four combination
of p- and s-polarized incidence and output, considering both the bulk and
surface optical nonlinearities in the electric dipole approximation. We found
that the measurement using $S_{in}-S_{out}$ is particularly useful in
determining the symmetry of the oxdized layer interface, which would lower the
effective symmetry of the surface from $C_{4v}$ to $C_{2v}.$ We also have shown
that the [011] and [0$\bar{1}$1] directions can be distinguished through the
analysis of p-incident and p-output confugration.


title:
Characteristics of Molecular-biological Systems and Process-network
  Synthesis

abstract:
  Graph Theoretic Process Network Synthesis is described as an introduction to
biological networks. Genetic, protein and metabolic systems are considered. The
theoretical work of Kauffman is discussed and amplified by critical property
excursions. The scaling apparent in biological systems is shown. Applications
to evolution and reverse engineering are construed. The use of several
programs, such as the Synprops, Design of molecules, Therm and Knapsack are
suggested as instruments to study biological process network synthesis. The
properties of robust self-assembly and Self-Organizing synthesis are important
contributors to the discussion. The bar code of life and intelligent design is
reviewed. The need for better data in biological systems is emphasized.


title:
Reinterpretation of Lorentz Transformation and resolution of Special
  Relativity's paradoxes

abstract:
  Lorentz Transformation is reinterpreted. It is shown that by admitting the
existence of a frame of reference with synchronized clocks, we conclude that
any other frame of reference that moves related to the first has desynchronized
clocks. From this conclusion we will arrive at a new expression to relate the
time of different frames of reference. We also arrive at a new expression to
relate the contraction of different frames. We will show that if the maximum
speed on a frame with synchronized clocks is the speed of light, then the speed
of light varies accordingly to the velocity of the frame of reference. The new
interpretation of Lorentz Transformation explains and solves Relativity's
paradoxes.


title: Quantum three-body system in D dimensions

abstract:
  The independent eigenstates of the total orbital angular momentum operators
for a three-body system in an arbitrary D-dimensional space are presented by
the method of group theory. The Schr\"{o}dinger equation is reduced to the
generalized radial equations satisfied by the generalized radial functions with
a given total orbital angular momentum denoted by a Young diagram
$[\mu,\nu,0,...,0]$ for the SO(D) group. Only three internal variables are
involved in the functions and equations. The number of both the functions and
the equations for the given angular momentum is finite and equal to
$(\mu-\nu+1)$.


title:
Theory of angular correlation for double photoionization in a rare gas
  atom due to linearly polarized light

abstract:
  In this paper we have tried to establish a theory for angular correlation
between the photo- and Auger electrons in the two-step double photoionization
of a rare gas atom. The basic finding of this paper is that a general
theoretical expression for the angular correlation function is established in
the problem of double photoionization of atoms in the presence of linearly
polarized monochromatic light. We consider the case of a xenon atom and the
incident light is of (94.5 eV) with arbitrary linear polarization. The
theoretical results are compared with the experiments done by K(\ddot{a}
)mmerling and Schmidt [J.Phys.B, 26,1141(1993)].


title: Probability density function of turbulent velocity fluctuation

abstract:
  The probability density function (PDF) of velocity fluctuations is studied
experimentally for grid turbulence in a systematical manner. At small distances
from the grid, where the turbulence is still developing, the PDF is
sub-Gaussian. At intermediate distances, where the turbulence is fully
developed, the PDF is Gaussian. At large distances, where the turbulence has
decayed, the PDF is hyper-Gaussian. The Fourier transforms of the velocity
fluctuations always have Gaussian PDFs. At intermediate distances from the
grid, the Fourier transforms are statistically independent of each other. This
is the necessary and sufficient condition for Gaussianity of the velocity
fluctuations. At small and large distances, the Fourier transforms are
dependent.


title: Study of the NLC Linac Optics Compatible with a Low Energy Scenario

abstract:
  We explore the NLC linac optics compatible with a low energy scenario where
initially only part of the full linac is installed. Optics modification
suitable for a low energy beam running and upgrade to the nominal energy is
discussed. Linac parameters and beam tolerances in the modified lattice are
compared to the nominal design.


title: Enhanced inverse bremsstrahlung heating rates in a strong laser field

abstract:
  Test particle studies of electron scattering on ions, in an oscillatory
electromagnetic field have shown that standard theoretical assumptions of small
angle collisions and phase independent orbits are incorrect for electron
trajectories with drift velocities smaller than quiver velocity amplitude. This
leads to significant enhancement of the electron energy gain and the inverse
bremsstrahlung heating rate in strong laser fields. Nonlinear processes such as
Coulomb focusing and correlated collisions of electrons being brought back to
the same ion by the oscillatory field are responsible for large angle, head-on
scattering processes. The statistical importance of these trajectories has been
examined for mono-energetic beam-like, Maxwellian and highly anisotropic
electron distribution functions. A new scaling of the inverse bremsstrahlung
heating rate with drift velocity and laser intensity is discussed.


title:
Non-white noise and a multiple-rate Markovian closure theory for
  turbulence

abstract:
  Markovian models of turbulence can be derived from the renormalized
statistical closure equations of the direct-interaction approximation (DIA).
Various simplifications are often introduced, including an assumption that the
two-time correlation function is proportional to the renormalized infinitesimal
propagator (Green's function), i.e. the decorrelation rate for fluctuations is
equal to the decay rate for perturbations. While this is a rigorous result of
the fluctuation--dissipation theorem for thermal equilibrium, it does not
necessarily apply to all types of turbulence. Building on previous work on
realizable Markovian closures, we explore a way to allow the decorrelation and
decay rates to differ (which in some cases affords a more accurate treatment of
effects such as non-white noise), while retaining the computational advantages
of a Markovian approximation. Some Markovian approximations differ only in the
initial transient phase, but the multiple-rate Markovian closure (MRMC)
presented here could modify the steady-state spectra as well. Markovian models
can be used directly in studying turbulence in a wide range of physical
problems (including zonal flows, of recent interest in plasma physics), or they
may be a useful starting point for deriving subgrid turbulence models for
computer simulations.


title: An accurate spectral method for solving the Schroedinger equation

abstract:
  The solution of the Lippman-Schwinger (L-S) integral equation is equivalent
to the the solution of the Schroedinger equation. A new numerical algorithm for
solving the L-S equation is described in simple terms, and its high accuracy is
confirmed for several physical situations. They are: the scattering of an
electron from a static hydrogen atom in the presence of exchange, the
scattering of two atoms at ultra low temperatures, and barrier penetration in
the presence of a resonance for a Morse potential. A key ingredient of the
method is to divide the radial range into partitions, and in each partition
expand the solution of the L-S equation into a set of Chebyshev polynomials.
The expansion is called "spectral" because it converges rapidly to high
accuracy. Properties of the Chebyshev expansion, such as rapid convergence, are
illustrated by means of a simple example.


title: Foam: A General-Purpose Cellular Monte Carlo Event Generator

abstract:
  A general purpose, self-adapting, Monte Carlo (MC) event generator
(simulator) is described. The high efficiency of the MC, that is small maximum
weight or variance of the MC weight is achieved by means of dividing the
integration domain into small cells. The cells can be $n$-dimensional
simplices, hyperrectangles or Cartesian product of them. The grid of cells,
called ``foam'', is produced in the process of the binary split of the cells.
The choice of the next cell to be divided and the position/direction of the
division hyper-plane is driven by the algorithm which optimizes the ratio of
the maximum weight to the average weight or (optionally) the total variance.
The algorithm is able to deal, in principle, with an arbitrary pattern of the
singularities in the distribution. As any MC generator, it can also be used for
the MC integration. With the typical personal computer CPU, the program is able
to perform adaptive integration/simulation at relatively small number of
dimensions ($\leq 16$). With the continuing progress in the CPU power, this
limit will get inevitably shifted to ever higher dimensions. {\tt Foam} is
aimed (and already tested) as a component in the MC event generators for the
high energy physics experiments. A few simple examples of the related
applications are presented. {\tt Foam} is written in fully object-oriented
style, in the C++ language. Two other versions with a slightly limited
functionality, are available in the Fortran77 language. The source codes are
available from http://jadach.home.cern.ch/jadach/


title: Some effects of metastable substance observed in erosive discharges

abstract:
  The brief characteristic of a place and state of modern experimental
investigations of a ball lightning on the basis of metastable substance is
given.


title: Fundamentals of a theory of elementary actions

abstract:
  Those articles (versions) explore a non conventional pregeometrical model
encompassing quantics and geometrodynamics (a stochastic graph relational
theory).
  Some key points are :
  1) the use of simple boolean atom-like far subquantum entities connected with
action links deriving from probabilistic laws (acteons).
  2) the concept of structures as correlated nets of relations.
  3) the relational definition of locus and processual definition of distances,
with implied consequences on how the physical universe should be conceived in
such a model.
  Added versions improve and extend the idea on mathematical grounds.


title: Enhanced radiative ion cooling

abstract:
  Enhanced radiative cooling of ion beams in storage rings and Robinson's
damping criterion are discussed.


title: Optimization of a Langmuir-Taylor detector for lithium

abstract:
  This paper describes the construction and optimization of a Langmuir-Taylor
detector for lithium, using a rhenium ribbon. The absolute detection
probability of this very sensitive detector is measured and the dependence of
this probability with oxygen pressure and surface temperature is studied.
Sources of background signal and their minimization are also discussed in
details. And a comparison between our data concerning the response time of the
detector and literature values is given. A theoretical analysis has been made:
this analysis supports the validity of the Saha-Langmuir law to relate the
ionization probability to the work function. Finally, the rapid variations of
the work function with oxygen pressure and temperature are explained by a
chemical equilibrium model.


title: Time series analysis for minority game simulations of financial markets

abstract:
  The minority game (MG) model introduced recently provides promising insights
into the understanding of the evolution of prices, indices and rates in the
financial markets. In this paper we perform a time series analysis of the model
employing tools from statistics, dynamical systems theory and stochastic
processes. Using benchmark systems and a financial index for comparison,
several conclusions are obtained about the generating mechanism for this kind
of evolut ion. The motion is deterministic, driven by occasional random
external perturbation. When the interval between two successive perturbations
is sufficiently large, one can find low dimensional chaos in this regime.
However, the full motion of the MG model is found to be similar to that of the
first differences of the SP500 index: stochastic, nonlinear and (unit root)
stationary.


title: Stimulated Nutation Echo: Dynamic and Decay Properties

abstract:
  We study experimentally the dynamical and decay properties of the Stimulated
Nutation Echo (SNE) in a two-level spin system. This is the signal which
appears in the transient response of the system to the second pulse at time
tau_1 elapsed from its beginning and coinciding with the duration of the first
pulse. The information about the first pulse duration is imprinted into the
population difference of the inhomogeneously broadened ensemble of the
two-level absorbers. The decay of the SNE signal has two contributions. One
originates from the population decay during the time tau between the pulses.
Another is caused by the coherence loss during the excitation by the first
pulse and the reading time of the second pulse. Experimental results on the
decay properties induced by these mechanisms are presented. The dependence of
these decay rates on the pulse intensity is discussed, and its relationship
with the anomalous (non-Bloch) decay of other coherent transients in solids is
examined.


title:
Magnetic Field Effects on the 1083 nm Atomic Line of Helium. Optical
  Pumping of Helium and Optical Polarisation Measurement in High Magnetic Field

abstract:
  The structure of the excited $2^{3}$S and $2^{3}$P triplet states of $^{3}$He
and $^{4}$He in an applied magnetic field B is studied using different
approximations of the atomic Hamiltonian. All optical transitions (line
positions and intensities) of the 1083 nm $2^{3}$S-$2^{3}$P transition are
computed as a function of B. The effect of metastability exchange collisions
between atoms in the ground state and in the $2^{3}$S metastable state is
studied, and rate equations are derived, for the populations these states in
the general case of an isotopic mixture in an arbitrary field B. It is shown
that the usual spin-temperature description remains valid. A simple optical
pumping model based on these rate equations is used to study the B-dependence
of the population couplings which result from the exchange collisions. Simple
spectroscopy measurements are performed using a single-frequency laser diode on
the 1083 nm transition. The accuracy of frequency scans and of measurements of
transition intensities is studied. Systematic experimental verifications are
made for B=0 to 1.5 T. Optical pumping effects resulting from hyperfine
decoupling in high field are observed to be in good agreement with the
predictions of the simple model. Based on adequately chosen absorption
measurements at 1083 nm, a general optical method to measure the nuclear
polarisation of the atoms in the ground state in an arbitrary field is
described. It is demonstrated at $B\sim$0.1 T, a field for which the usual
optical methods could not operate.


title: Non-premixed Flame-Turbulence Interaction in Compressible Turbulent Flow

abstract:
  Nonpremixed turbulent reacting flows are intrinsically difficult to model due
to the strong coupling between turbulent motions and reaction. The large amount
of heat released by a typical hydrocarbon flame leads to significant
modifications of the thermodynamic variables and the molecular transport
coefficients and thus alters the fluid dynamics. Additionally, in nonpremixed
combustion, the flame has a complex spatial structure. Localized expansions and
contractions occur, enhancing the dilatational motions. Therefore, the
compressibility of the flow and the heat release are intimately related.
However, fundamental studies of the role of compressibility on the scalar
mixing and reaction are scarce. In this paper we present results concerning the
fundamental aspects of the interaction between non-premixed flame and
compressible turbulence.


title:
Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field
  Penetration

abstract:
  A novel nonlinear effect of anomalously deep penetration of an external radio
frequency electric field into a plasma is discribed. A self-consistent kinetic
treatment reveals a transition region between the sheath and the plasma.
Because of the electron velocity modulation in the sheath, bunches in the
energetic electron density are formed in the transition region adjusted to the
sheath. The width of the region is of order $V_{T}/\omega$, where V_{T} is the
electron thermal velocity, and $\omega$ is frequency of the electric field. The
presence of the electric field in the transition region results in a cooling of
the energetic electrons and an additional heating of the cold electrons in
comparison with the case when the transition region is neglected.


title:
Exponential Basis in Two-Sided Variational Estimates of Energy for
  Three-Body Systems

abstract:
  By the use of the variational method with exponential trial functions the
upper and lower bounds of energy are calculated for a number of
non-relativistic three-body Coulomb and nuclear systems. The formulas for
calculation of upper and lower bounds for exponential basis are given, the
lower bounds for great part of systems were calculated for the first time. By
comparison of calculations for different bases the efficiency of exponential
trial functions and their universality in respect to masses of particles and
interaction are demonstrated. The advantage of exponential basis manifests
mostly evident for the systems with comparable masses, though its use in
one-center and two-center problems is justified too. For effective solution of
two-center problem a carcass modification of the trial function is proposed.
The stability of various three-particle Coulomb systems is analyzed.


title: Approximate Solutions of Quantum Equations for Electron Gas in Plasma

abstract:
  We have obtained the solutions of linearized Shr{\"o}dinger equation for
spherically and axially symmetrical electrons density oscillations in plasma in
the approximation of the self-consistent field. It was shown that in the center
or on the axis of symmetry of such a system the static density of electrons can
enhance, which leads to the increasing of density and pressure of ion gas. We
suggest that this mechanism could be realized in nature as rare phenomenon
called the 'fireball' and could be used in carrying out the research concerning
controlled fusion.


title: The relation of morphology and affinity maturation in germinal centers

abstract:
  The specific morphology of germinal centers is analyzed in the context of the
optimization of the humoral immune response. The relevance of dark and light
zones for the affinity maturation process is investigated in the framework of a
theoretical model for the germinal center reaction. Especially, it is shown
that an intermediate appearance of dark zones in germinal center reactions is
advantageous for the process of antibody optimization. Methodological aspects
are discussed.


title:
The configuration of a topological current and physical structure: an
  application and paradigmatic evidence

abstract:
  In the $\phi $-mapping theory, the topological current constructed by the
order parameters can possess different inner structure. The difference in
topology must correspond to the difference in physical structure. The
transition between different structures happens at the bifurcation point of the
topological current. In a self-interaction two-level system, the change of
topological particles corresponds to change of energy levels.


title: Fractional Derivative Analysis of Helmholtz and Paraxial-Wave Equations

abstract:
  Fundamental rules and definitions of Fractional Differintegrals are outlined.
Factorizing 1-D and 2-D Helmholtz equations four fractional eigenfunctions are
determined. The functions exhibit incident and reflected plane waves as well as
diffracted incident and reflected waves of the half-plane edge. They allow to
construct the Sommerfeld half-plane diffraction solutions. Parabolic-Wave
Equation (PWE, Leontovich-Fock) for paraxial propagation is factorized and
differetial fractional solutions of Fresnel-integral type are derived. We
arrived at two solutions, which are the mothers of known and new solutions.


title: Towards a third-order topological invariant for magnetic fields

abstract:
  An expression for a third-order link integral of three magnetic fields is
presented. It is a topological invariant and therefore an invariant of ideal
magnetohydrodynamics. The integral generalizes existing expressions for
third-order invariants which are obtained from the Massey triple product, where
the three fields are restricted to isolated flux tubes. The derivation and
interpretation of the invariant shows a close relationship with the well-known
magnetic helicity, which is a second-order topological invariant. Using gauge
fields with an SU(2) symmetry, helicity and the new third-order invariant
originate from the same identity, an identity which relates the second Chern
class and the Chern-Simons three-form. We present an explicit example of three
magnetic fields with non-disjunct support. These fields, derived from a vacuum
Yang-Mills field with a non-vanishing winding number, possess a third-order
linkage detected by our invariant.


title:
Non-adiabatic coupling and adiabatic population transfer in quantum
  molecular systems

abstract:
  We show that a counter-intuitive pulse sequence leads to adiabatic passage
between the vibrational levels of three harmonic potentials through parallel
dark states in adiabatic approximation. However, the adiabatic assumptions
break down for very intense pulses and non-adiabatic couplings result in the
population transfer by light-induced potential shaping.


title:
From Laser Induced Line Narrowing To Electromagnetically Induced
  Transparency: Closed System Analysis

abstract:
  Laser induced line narrowing effect, discovered more than thirty years ago,
can also be applied to recent studies in high resolution spectroscopy based on
electromagnetically induced transparency. In this paper we first present a
general form of the transmission width of electromagnetically induced
transparency in a homogeneously broadened medium. We then analyze a Doppler
broadened medium by using a Lorentzian function as the atomic velocity
distribution. The dependence of the transmission linewidth on the driving field
intensity is discussed and compared to the laser induced line narrowing effect.
This dependence can be characterized by a parameter which can be regarded as
``the degree of optical pumping''.


title:
The zero point field and the reduction of the wave packet in
  semiclassical electrodynamics

abstract:
  In the classical theory, an electromagnetic field obeying Maxwell's equations
cannot be absorbed quickly by matter, so that it remains a zero point field.
Splitting the total, genuine electromagnetic field into the sum of a
conventional field and a zero point field is physically meaningless until a
receiver attenuates the genuine field down to the zero point field, or studying
the amplification of the zero point field by a source.
  In classical optics all optical effects must be written using the genuine
field, so that at low light levels the nonlinear effects become linear in
relation to the conventional field. The result of the interpretation of all
observations, even at low light levels, is exactly the same in quantum
electrodynamics and in the semi- classical theory.
  The zero point field is stochastic only far from the sources and the
receivers; elsewhere, it is shaped by matter, it may be studied through fields
visible before an absorption or after an amplification.
  A classical study of the reduction of the wave packet extends the domain of
equivalence of the classical and quantum zero point field; using both
interpretations of this field makes the results more reliable, because the
traps are different.


title: Water wave propagation and scattering over topographical bottoms

abstract:
  Here I present a general formulation of water wave propagation and scattering
over topographical bottoms. A simple equation is found and is compared with
existing theories. As an application, the theory is extended to the case of
water waves in a column with many cylindrical steps.


title: Low-energy electron scattering in a strong Coulomb field

abstract:
  The analytic expression for the cross section of low-energy electron
scattering in a strong Coulomb field is obtained. It is shown that in a wide
energy region this cross section differs essentially from that obtained in the
first Born approximation.


title:
Parallel J-W Monte Carlo Simulations of Thermal Phase Changes in
  Finite-size Systems

abstract:
  The thermodynamic properties of 59 TeF6 clusters that undergo
temperature-driven phase transitions have been calculated with a canonical
J-walking Monte Carlo technique. A parallel code for simulations has been
developed and optimized on SUN3500 and CRAY-T3E computers. The Lindemann
criterion shows that the clusters transform from liquid to solid and then from
one solid structure to another in the temperature region 60-130 K.

categories: physics.comp-ph physics.atm-clus physics.atom-ph physics.bio-ph


title:
Charge Dependence of Temperature-Driven Phase Transitions of Molecular
  Nanoclusters: Molecular Dynamics Simulation

abstract:
  Phase transitions (liquid-solid, solid-solid) triggered by temperature
changes are studied in free nanosized clusters of TeF_6 (SF_6) with different
negative charges assigned to the fluorine atoms. Molecular dynamics simulations
at constant energy show that the charge increase from q_F=0.1 e to q_F=0.25 e
shifts the melting temperature towards higher values and some of the metastable
solid states disappear. The increased repulsive interaction maintains the order
in molecular systems at higher temperatures.

categories: physics.atm-clus physics.atom-ph physics.bio-ph physics.comp-ph


title: Cold atoms in optical lattices :a Hamiltonian ratchet

abstract:
  We investigate a new type of quantum ratchet which may be realised by cold
atoms in a double-well optical lattice which is pulsed with unequal periods.
  The classical dynamics is chaotic and we find the classical diffusion rate
$D$ is asymmetric in momentum up to a finite time $t_r$.
  The quantum behaviour produces a corresponding asymmetry in the momentum
distribution which is 'frozen-in' by Dynamical Localisation provided the
break-time $t^* > t_r$. We conclude that the cold atom ratchets require $Db/
\hbar \sim 1$ where b is a small deviation from period-one pulses.


title:
Coulomb-Volkov approach of ionization by extreme ultraviolet laser
  pulses in the subfemtosecond regime

abstract:
  In conditions where the interaction betweeen an atom and a short
high-frequency extreme ultraviolet laser pulse is a perturbation, we show that
a simple theoretical approach, based on Coulomb-Volkov-type states, can make
reliable predictions for ionization. To avoid any additional approximation, we
consider here a standard case : the ionization of hydrogen atoms initially in
their ground state. For any field parameter, we show that the method provides
accurate energy spectra of ejected electrons, including many above threshold
ionization peaks, as long as the two following conditions are simultaneously
fulfilled : (i) the photon energy is greater than or equal to the ionization
potential ; (ii) the ionization process is not saturated. Thus, ionization of
atoms or molecules by the high order harmonic laser pulses which are generated
at present may be addressed through this Coulomb-Volkov treatment.


title: A Local Ensemble Kalman Filter for Atmospheric Data Assimilation

abstract:
  In this paper, we introduce a new, local formulation of the ensemble Kalman
Filter approach for atmospheric data assimilation. Our scheme is based on the
hypothesis that, when the Earth's surface is divided up into local regions of
moderate size, vectors of the forecast uncertainties in such regions tend to
lie in a subspace of much lower dimension than that of the full atmospheric
state vector of such a region. Ensemble Kalman Filters, in general, assume that
the analysis resulting from the data assimilation lies in the same subspace as
the expected forecast error. Under our hypothesis the dimension of this
subspace is low. This implies that operations only on relatively low
dimensional matrices are required. Thus, the data analysis is done locally in a
manner allowing massively parallel computation to be exploited. The local
analyses are then used to construct global states for advancement to the next
forecast time. The method, its potential advantages, properties, and
implementation requirements are illustrated by numerical experiments on the
Lorenz-96 model. It is found that accurate analysis can be achieved at a cost
which is very modest compared to that of a full global ensemble Kalman Filter.

categories: physics.ao-ph nlin.CD physics.data-an physics.geo-ph


title: Laser polarization of positron beam

abstract:
  For a number of physical studies which are planned to be made with the next
generation colliders, it is necessary to use polarized beams of both electrons
and positrons. The problem of producing and acceleration of polarized electrons
may be considered to be solved, but the existing approaches to create polarized
positron beams do not ensure the parameters required. This work proposes a new
approach to produce polarized positron beams, which is based on the process of
multiple Compton backscattering of unpolarized ultrarelativistic positrons in
the field of intense circularly polarized laser wave.


title: Measuring the Entropy and Testing the Second Law of Thermodynamics

abstract:
  Evidence implies that basic laws of thermodynamics must be tested by
experiments. In this paper, an experiment is designed to measure the entropy of
a system with at least one known (measurable) equation of state, especially the
gas systems. Since the entropy can be measured now, the formulae related to the
second law of thermodynamics can be examined by other experiments.


title: Floating Bodies of Equilibrium I

abstract:
  A long cylindrical body of circular cross-section and homogeneous density may
float in all orientations around the cylinder axis. It is shown that there are
also bodies of non-circular cross-sections which may float in any direction.
Apart from those found by Auerbach for rho=1/2 there are one-parameter families
of cross-sections for rho not= 1/2 which have a p-fold rotation axis. For given
p they exist for p-2 densities rho. There are strong indications, that for all
p-2 densities one has the same family of cross-sections. (Proven in
physics/0205059)


title:
Optical feedback and the coupling problem in semiconductor microdisk
  lasers

abstract:
  The smaller the size of a light-emitting microcavity, the more important it
becomes to understand the effects of the cavity boundary on the optical mode
profile. Conventional methods of laser physics, such as the paraxial
approximation, become inapplicable in many of the more exotic cavity designs to
be discussed here. Cavities in the shape of microdisks, pillars and rings can
yield low lasing thresholds in a wide variety of gain media: quantum wells,
wires and even dots, as well as quantum cascade superlattices and GaN. An
overview of the experimental and theoretical status is provided, with special
emphasis on the light extraction problem.


title: Chaotic light: a theory of asymmetric resonant cavities

abstract:
  Spherical and cylindrical dielectric cavities support high Q whispering
gallery modes due to total internal reflection of the trapped light. When such
a cavity is deformed smoothly the ray dynamics of these modes becomes chaotic
in a manner determined by the KAM theory of classical hamiltonian dynamics. The
universal properties of the ray dynamics predicted by KAM theory allow a
general understanding of the whispering gallery modes of such asymmetric
resonant cavities (ARCs). This theory combined with simulations of the
non-linear map describing the ray motion provides the basis for a ray-optics
model of the Q-spoiling of these whispering gallery modes for large
deformations (greater than 1% of the radius). The model predicts a sharp onset
as a function of deformation for significant Q-spoiling of these modes and
highly directional emission above this threshold. Solution of the wave equation
for typical whispering gallery modes confirms the qualitative behavior
predicted by the ray-optics model even when the cavity is only a few times the
resonant wavelength. The model explains for the first time the lasing intensity
profile of highly deformed lasing droplets.


title: The sequential-reflection model in deformed dielectric cavities

abstract:
  The stationary states of a microlaser are related to the decaying quasibound
states of the corresponding passive cavity. These are interpreted classically
as originating from sequential escape attempts of an ensemble of rays obeying a
curvature-corrected Fresnel formula. Polarization-dependent predictions of this
model, and its limitations for stable orbits in partially chaotic systems are
discussed.


title:
Angular correlation theory for double photoionization in a rare gas atom
  : ionization by polarized photons

abstract:
  This is a sequel to an earlier article on the theory of angular correlation
for double photoionization. Here we consider the two-step double
photoionization of a rare gas atom under the influence of a polarized photon
beam described by appropriate Stokes parameters. Cylindrical mirror analysers
(CMA) are used to detect the outgoing electrons. Theoretical values of the
correlation functions are obtained for linearly polarized light. Two different
situations is handled. Once, the value of the correlation function is obtained
keeping the photo-electron in a fixed direction. The other case the direction
of the Auger electron is kept fixed. Comparison with experiments on xenon shows
excellent agreement for the case of (4d_{5/2}) photoionization followed by a
subsequent (N_{5}-O_{23}O_{23} ^{1}S_{0}) Auger decay for a polarized incident
photon of energy (94.5eV) {[}J. Phys.B,


title:
The Eleven Questions About The Cosmos Answered : Let The Cognoscenti
  Decide

abstract:
  The National Academy of Sciences USA has posed eleven important questions
about the Cosmos. This paper answers most of the questions based on the new
concepts about "What is Time - A New Mathematico Physical And Information
Theoretic Approach" [physics/0106073] and "Estimation of Gravitational Constant
from CMBR data and Hubble's parameter" [physics/0106083]. The answers in brief
as well as some explanatory notes have been appended to each question.


title:
Isotropic photonic band gap and anisotropic structures in transmission
  spectra of two-dimensional 5-fold and 8-fold symmetric quasiperiodic photonic
  crystals

abstract:
  We measured and calculated transmission spectra of two-dimensional
quasiperiodic photonic crystals (PCs) based on a 5-fold (Penrose) or 8-fold
(octagonal) symmetric quasiperiodic pattern. The photonic crystal consisted of
dielectric cylindrical rods in air placed normal to the basal plane on vertices
of tiles composing the quasiperiodic pattern. An isotropic photonic band gap
(PBG) appeared in the TM mode, where electric fields were parallel to the rods,
even when the real part of a dielectric constant of the rod was as small as
2.4. An isotropic PBG-like dip was seen in tiny Penrose and octagonal PCs with
only 6 and 9 rods, respectively. These results indicate that local multiple
light scattering within the tiny PC plays an important role in the PBG
formation. Besides the isotropic PBG, we found dips depending on the incident
angle of the light. This is the first report of anisotropic structures clearly
observed in transmission spectra of quasiperiodic PCs. Based on rod-number and
rod-arrangement dependence, it is thought that the shapes and positions of the
anisotropic dips are determined by global multiple light scattering covering
the whole system. In contrast to the isotropic PBG due to local light
scattering, we could not find any PBGs due to global light scattering even
though we studied transmission spectra of a huge Penrose PC with 466 rods.


title: Stochastic analysis of road surface roughness

abstract:
  This paper was withdrawn by the authors due to significant new findings. A
new paper on the same topic has been submitted as physics/0310159.


title:
Four-wave interaction in gas and vacuum. Definition of a third order
  nonlinear effective susceptibility in vacuum

abstract:
  Semiclassical methods are used to study the nonlinear interaction of light in
vacuum in the context of four wave mixing. This study is motivated by a desire
to investigate the possibility of using recently developed powerful ultrashort
(femtosecond) laser pulses to demonstrate the existence of nonlinear effects in
vacuum, predicted by quantum electrodynamics (QED). An approach, similar to
classical nonlinear optics in a medium, is developed in this article. A third
order nonlinear effective susceptibility of vacuum is then introduced .