title:
The Architecture of Idiotypic Networks: Percolation and Scaling
  Behaviour

abstract:
  We investigate a model where idiotypes (characterizing B-lymphocytes and
antibodies of an immune system) and anti-idiotypes are represented by
complementary bitstrings of a given length d allowing for a number of
mismatches (matching rules). In this model, the vertices of the hypercube in
dimension d represent the potential repertoire of idiotypes. A random set of
(with probability p) occupied vertices corresponds to the expressed repertoire
of idiotypes at a given moment. Vertices of this set linked by the above
matching rules build random clusters. We give a structural and statistical
characterisation of these clusters - or in other words - of the architecture of
the idiotypic network. Increasing the probability p one finds at a critical p a
percolation transition where for the first time a large connected graph occures
with probability one. Increasing p further, there is a second transition above
which the repertoire is complete in the sense that any newly introduced
idiotype finds a complementary anti-idiotype. We introduce structural
characteristics such as the mass distributions and the fragmentation rate for
random clusters, and determine the scaling behaviour of the cluster size
distribution near the percolation transition, including finite size
corrections. We find that slightly above the percolation transition the large
connected cluster (the central part of the idiotypic network) consists
typically of one highly connected part and a number of weakly connected
constituents and coexists with a number of small, isolated clusters. This is in
accordance with the picture of a central and a peripheral part of the idiotypic
network and gives some support to idealized architectures of the central part
used in recent dynamical mean field models.


title: Bound states of negatively charged ions induced by a magnetic field

abstract:
  We analyse the bound states of negatively charged ions which were predicted
to exist because of the presence of a magnetic field by Avron et al. We confirm
that the number of such states is infinite in the approximation of an
infinitely heavy nucleus and provide insight into the underlying physical
picture by means of a combined adiabatic and perturbation theoretical approach.
We also calculate the corresponding binding energies which are qualitatively
different for the states with vanishing and non-vanishing angular momentum. An
outlook on the case of including center of mass effects is presented.

categories: physics.atom-ph physics.chem-ph physics.gen-ph physics.plasm-ph


title:
Finite-Difference Calculations for Atoms and Diatomic Molecules in
  Strong Magnetic and Static Electric Fields

abstract:
  Fully numerical mesh solutions of 2D quantum equations of Schroedinger and
Hartree-Fock type allow us to work with wavefunctions which possess a very
flexible geometry. This flexibility is especially important for calculations of
atoms and molecules in strong external fields where neither the external field
nor the internal interactions can be considered as a perturbation. The
applications of the present approach include calculations of atoms and diatomic
molecules in strong static electric and magnetic fields. For the latter we have
carried out Hartree-Fock calculations for He, Li, C and several other atoms.
This yields in particular the first comprehensive investigation of the ground
state configurations of the Li and C atoms in the whole range of magnetic
fields (0<B<10000 a.u.) and a study of the ground state electronic
configurations of all the atoms with 1<Z<11 and their ions A^+ in the
high-field fully spin-polarised regime. The results in a case of a strong
electric field relate to single-electron systems including the correct solution
of the Schroedinger equation for the H_2^+ ion (energies and decay rates) and
the hydrogen atom in strong parallel electric and magnetic fields.

categories: physics.atom-ph physics.chem-ph physics.comp-ph physics.plasm-ph


title:
Excited states of the hydrogen molecule in magnetic fields: The singlet
  Sigma states of the parallel configuration

abstract:
  Excited states of the hydrogen molecule subject to a homogeneous magnetic
field are investigated for the parallel configuration in the complete regime of
field strengths B=0-100a.u.. Up to seven excitations are studied for gerade as
well as ungerade spin singlet states of Sigma symmetry with a high accuracy.
The evolution of the potential energy curves for the individual states with
increasing field strength as well as the overall behaviour of the spectrum are
discussed in detail. A variety of phenomena like for example the sequence of
changes for the dissociation channels of excited states and the resulting
formation of outer wells are encountered. Possible applications of the obtained
data to the analysis of magnetic white dwarfs


title: Quantum energy flow in atomic ions moving in magnetic fields

abstract:
  Using a combination of semiclassical and recently developed wave packet
propagation techniques we find the quantum self-ionization process of highly
excited ions moving in magnetic fields which has its origin in the energy
transfer from the center of mass to the electronic motion. It obeys a time
scale by orders of magnitude larger than the corresponding classical process.
Importantly a quantum coherence phenomenon leading to the intermittent
behaviour of the ionization signal is found and analyzed. Universal properties
of the ionization process are established.


title:
Laser generated wake fields as a new diagnostic tool for magnetized
  plasmas

abstract:
  In the presence of an external magnetic field, wake fields generated by a
short laser pulse can propagate out of the plasma, and thereby provide
information about the electron density profile. A method for reconstructing the
density profile from a measured wake field spectrum is proposed and a numerical
example is given. Finally, we compare our proposal with existing plasma density
diagnostic techniques.


title: A Modified Theory Of Newtonian Mechanics

abstract:
  A specific form of the inertial law is presented by which we can have some
deeper insight into the essence of mass and inertia. In this modified theory,
there is no need to keep the concept of absolute space and Newton's third law
as principles. By introducing a convenient form for gravitational law the
coupling constant G becomes a function of inertial parameters of the universe.


title:
Stable oscillating nonlinear beams in
  square-wave-biased-photorefractives

abstract:
  We demonstrate experimentally that in a centrosymmetric paraelectric
non-stationary boundary conditions can dynamically halt the intrinsic
instability of quasi-steady-state photorefractive self-trapping, driving beam
evolution into a stable oscillating two-soliton-state configuration.


title: Astrophysical Dynamics 1999/2000: Merging Research and Education

abstract:
  The workshop `Astrophysical Dynamics 1999/2000' followed a homonymous
advanced research course, and both activities were organized by me. In this
opening paper of the proceedings book, I describe them and document their
strong impact on the academic life of the local institutions. The advanced
research course was open to graduate students, senior researchers, and
motivated under-graduate students with good background in physics and
mathematics. The course covered several multi-disciplinary issues of modern
research on astrophysical dynamics, and thus also of interest to physicists,
mathematicians and engineers. The major topic was gas dynamics, viewed in
context with stellar dynamics and plasma physics. The course was complemented
by parallel seminars on hot topics given by experts in such fields, and open to
a wide scientific audience. In particular, I gave a friendly introduction to
wavelets, which are becoming an increasingly powerful tool not only for
processing signals and images but also for analysing fractals and turbulence,
and which promise to have important applications to dynamical modelling of disc
galaxies. The workshop was open to a wide scientific audience. The workshop
with published proceedings book was, as a matter of fact, the innovative form
of exam that I proposed for the advanced research course. The contributions
were refereed and their quality is high on average, exceptionally high in a few
cases. The advanced research course and the workshop all together produced
great enthusiasm in the students and welcomed the participation of a hundred
different people, which means an order of magnitude more than an average
graduate course at Chalmers University of Technology and G\"oteborg University.

categories: physics.ed-ph astro-ph math-ph math.MP physics.pop-ph physics.soc-ph


title: The quest for the neutrino mass spectrum

abstract:
  This article provides a (semi-)popular introduction to the phenomenology of
neutrino masses.

categories: physics.pop-ph astro-ph hep-ex hep-ph nucl-ex nucl-th


title:
Pair production and electron capture in relativistic heavy-ion
  collisions

abstract:
  Results are presented for simulations of electron-positron pair production in
relativistic heavy-ion collisions leading to electron capture and positron
ejection. We apply a two-center relativistic continuum distorted-wave model to
represent the electron/positron dynamics during the collision process. The
results are compared with experimental cross-section data for ${\rm La}^{57+}$
and ${\rm Au}^{79+}$ impact on Gold, Silver and Copper targets. The theory is
in very good agreement with experiment, verifying the result that the process
increases in importance with both collision energy and target atomic number,
and improves upon previous simulations of this process.


title: The hydration number of Na+ in liquid water

abstract:
  An `ab initio' molecular dynamics simulation of a Na+ ion in aqueous solution
is presented and discussed. The calculation treats a Na+ ion and 32 water
molecules with periodic boundary conditions on a cubic volume determined by an
estimate of zero partial molar volume for this solute in water at normal
density and at a temperature of 344+/-24 K. Analysis of the last half of the 12
ps trajectory shows 4.6 water molecules occupying the inner hydration shell of
the Na+ ion on average, with 5 being the most probable occupancy. The
self-diffusion coefficient observed for the Na+ is 1.0 x 10$^{-5}$ cm$^2$/s.
The quasi-chemical theory of solutions provides the framework for two more
calculations. First a complementary calculation, based on electronic structure
results for ion-water clusters and a dielectric continuum model of outer sphere
hydration contributions, predicts an average hydration shell occupancy of 4.0.
This underestimate is attributed to the harmonic approximation for the clusters
in conjunction with the approximate dielectric continuum model treatment of
outer sphere contributions. Finally, a maximum entropy fitting of inner sphere
occupancies that leads to insensitive composite free energy approximations
suggests a value in the neighborhood of -68 kcal/mol for the hydration free
energy of Na+ (aq) under these conditions with no contribution supplied for
packing or van der Waals interactions.


title: Plasma Oscillations and Expansion of an Ultracold Neutral Plasma

abstract:
  We report the observation of plasma oscillations in an ultracold neutral
plasma. With this collective mode we probe the electron density distribution
and study the expansion of the plasma as a function of time. For classical
plasma conditions, i.e. weak Coulomb coupling, the expansion is dominated by
the pressure of the electron gas and is described by a hydrodynamic model.
Discrepancies between the model and observations at low temperature and high
density may be due to strong coupling of the electrons.


title:
A collision-induced satellite in the Lyman Beta profile due to H-H
  collisions

abstract:
  We present a theoretical profile of the Lyman Beta line of atomic hydrogen
perturbed by collisions with neutral hydrogen atoms and protons. We use a
general unified theory in which the electric dipole moment varies during a
collision. A collision-induced satellite appears on Lyman Beta, correlated to
the B''\barB 1Sigma+u - X 1Sigma+g asymptotically forbidden transition of H_2.
As a consequence, the appearance of the line wing between Lyman Alpha and Lyman
Beta is shown to be sensitive to the relative abundance of hydrogen ions and
neutral atoms, and thereby to provide a temperature diagnostic for stellar
atmospheres and laboratory plasmas.

categories: physics.atom-ph physics.ao-ph physics.chem-ph physics.plasm-ph


title:
The Theory of Gravitation in the Space - Time with Fractal Dimensions
  and Modified Lorents Transformations

abstract:
  In the space and the time with a fractional dimensions the Lorents
transformations fulfill only as a good approach and become exact only when
dimensions are integer. So the principle of relativity (it is exact when
dimensions are integer) may be treated also as a good approximation and may
remain valid (but modified) in case of small fractional corrections to integer
dimensions of time and space. In this paper presented the gravitation field
theory in the fractal time and space (based on the fractal theory of time and
space developed by author early). In the theory are taken into account the
alteration of Lorents transformations for case including $v=c$ and are
described the real gravitational fields with spin equal 2 in the fractal time
defined on the Riemann or Minkowski measure carrier. In the theory introduced
the new "quasi-spin", given four equations for gravitational fields (with
different "quasi spins" and real and imaginary energies). For integer
dimensions the theory coincide with Einstein GR or Logunov- Mestvirichvili
gravitation theory.


title: A new solution for inflation

abstract:
  Many pedagogical introductions of cosmological inflation are effective due to
the simplicity of the relevant equations. Here an analytic solution of the
cosmological equations is presented and used as an example to discuss
fundamental aspects of the inflationary paradigm.

categories: physics.ed-ph astro-ph gr-qc physics.class-ph


title: Simulation of Urban Effects of Cloud Physical Parameters

abstract:
  A scale invariant, selfsimilar atmospheric eddy continuum exists in the
planetary atmospheric boundary layer spanning several orders of magnitude in
scales and gives rise to the observed fractal geometry for the global cloud
cover pattern. The global weather systems are manifestations of the unified
atmospheric eddy continuum with inherent mutual global-local energy exchange
and therefore local urban energy/pollution sources have long-range global
effects leading to climate change and environmental degradation. It is shown
that the observed scale invariant atmospheric eddy continuum originates from
the turbulence scale by the universal period doubling route to chaos eddy
growth phenomenon in the planetary atmospheric boundary layer. The cloud
dynamical, microphysical and electrical parameters are shown to be simple
unique functions of turbulence scale energy generation.


title:
Excitations of oscillations in loaded systems with internal degrees of
  freedom

abstract:
  We show that oscillations are excited in a complex system under the influence
of the external force, if the parameters of the system experience rapid change
due to the changes in its internal structure. This excitation is collision-like
and does not require any phase coherence or periodicity. The change of the
internal structure may be achieved by other means which may require much lower
energy expenses. The mechanism suggests control over switching oscillations on
and off and may be of practical use.


title: A path-integral approach to the collisionless Boltzmann gas

abstract:
  On contrary to the customary thought, the well-known ``lemma'' that the
distribution function of a collisionless Boltzmann gas keeps invariant along a
molecule's path represents not the strength but the weakness of the standard
theory. One of its consequences states that the velocity distribution at any
point is a condensed ``image'' of all, complex and even discontinuous,
structures of the entire spatial space. Admitting the inability to describe the
entire space with a microscopic quantity, this paper introduces a new type of
distribution function, called the solid-angle-average distribution function.
With help of the new distribution function, the dynamical behavior of
collisionless Boltzmann gas is formulated in terms of a set of integrals
defined by molecular paths. In the new formalism, not only that the
difficulties associated with the standard theory are surmounted but also that
some of practical gases become calculable in terms of today's computer.


title: Comment on "Observation of Superluminal Behaviors in Wave Propagation"

abstract:
  Mugnai et al. have reported an experiment in which microwave packets appear
to travel in air with a speed substantially greater than c. They calculate the
group velocity of their packets and find that it agrees with their experimental
result. That calculation is incorrect. A correct calculation gives a group
velocity less than c. The reported experimental result cannot be reconciled
with the Maxwell equations.


title: Photon findings

abstract:
  Two experiments were made using a microwave generator, which sent a narrow
beam, through a metallic plate with horizontal movement. At the other end a
horn antenna coupled to a field-strength detector. In linear polarization
double cycloids paths were found and in circular polarization spiral paths were
found. These experiments suggested that the photon is composed by two particles
in dynamic equilibrium. The description of this model is given later as well as
its parameters.


title: Whence the Gauge Fields arise

abstract:
  A gauge fields (and massive, too) arise from the production of the
probability by the spinors.


title: Quantum mechanics can be led by metrics in Minkowski's time-space world

abstract:
  A body of theory is completely different between relativity theory and
quantum mechanics. Most targeting physical phenomena are different between them
as well. Despite that both theories describe our time-space world, no one has
succeeded in arriving at one of these theories by using the other one,
deductively. Fusion of these two theories produced quantum field theory.
However this theory impresses us as a theory that was made by merging the two
theories by force. So this theory cannot indicate the reason why both
relativity theory and quantum mechanics exist in this world at the same time.
Here I show you that quantum mechanics can be led by the equation of
Minkowski's metrics, which stands up in the relativistic world of space and
time. This is the first report proving mathematically that quantum mechanics
can be born reductively in our relativistic world.


title: Mathematical investigation of the Boltzmann collisional operator

abstract:
  Problems associated with the Boltzmann collisional operator are unveiled and
discussed. By careful investigation it is shown that collective effects of
molecular collisions in the six-dimensional position and velocity space are
more sophisticated than they appear to be.


title: Twin paradox and space topology

abstract:
  If space is compact, then a traveller twin can leave Earth, travel back home
without changing direction and find her sedentary twin older than herself. We
show that the asymmetry between their spacetime trajectories lies in a
topological invariant of their spatial geodesics, namely the homotopy class.
This illustrates how the spacetime symmetry invariance group, although valid
{\it locally}, is broken down {\it globally} as soon as some points of space
are identified. As a consequence, any non--trivial space topology defines
preferred inertial frames along which the proper time is longer than along any
other one.


title: Dark matter and the origin of mass: a simplified semiclassical approach

abstract:
  The pervasive presence in space of a flux of high-speed, electrically
uncharged dark matter particles is examined here for potential consequences.
Dark matter interactions with ordinary matter are considered, and a model of
the dark matter flux is developed. In this model, the property of matter that
we designate as mass is a measure of the interaction cross section of ordinary
matter with the flux of dark matter. From this model emerge effects similar to
certain quantum phenomena, and also a flux-mediated attractive inverse-square
force between particles of ordinary matter. The occurrence of effects
resembling both quantum phenomena and effects resembling gravitational
phenomena in this model may enable a straightforward examination of convergence
of gravitational physics and quantum mechanics.


title: Golden Bars of Consensus and the Truth Quark

abstract:
  Scientists are imprisoned by Golden Bars of Consensus, says Burton Richter
(hep-ex/0001012). A case in point is the mass of the Truth Quark. The consensus
analysis of the experimental data indicates that the mass of the Truth Quark is
about 170 GeV. On the other hand, an alternative analysis of the same data
indicates that the mass of the Truth Quark is about 130 GeV. If the design of
future experiments, including trigger, event selection, data analysis
procedures, error analysis, etc., takes into account only the consensus value,
and if the consensus value happens to be incorrect, then results of future
experiments might be compromised.


title:
Combining Research Methods and Results from Psychology and Physics in
  the Investigation of Quantum Mechanics

abstract:
  Research methods and results from physics and psychology are used to explore
a question in quantum mechanics. In this investigation, an observer variable is
manipulated in an experimental context concerning the trajectory of electrons
affected by their movement through a Stern-Gerlach apparatus. The basis in
psychology concerning why the observer variable is significant in the
experimental context is discussed. This investigation can serve as a prototype
for more complicated investigations.


title:
Do Gravitational and Electromagnetic Fields Have Rest Masses in the
  Fractal Universe?

abstract:
  As well known rest masses of elementary particles and physical fields appear
when temperature of Universe become low enough and symmetry broke. Are there
another sources of rest masses that are consequences of other nature of rest
masses or it is the only methods for generating rest masses? What will be with
massless fields when the laws of symmetry are not exact laws but only are very
good approximation and the time is not homogeneous, as it is in the fractal
world? In this paper based on the fractal theory of time and space (developed
by author earlier) a possible source of rest masses caused by the fractional
dimensions (FD) of the time is considered. It gives rest masses (very small)
for all particles and fields including gravitational and electromagnetic
fields. The estimation of the values of the rest masses gives
$m_{g}=\sqrt{\epsilon (tt_{i})^{-1}}$, $m_{f}= \sqrt{(t_{0}t_{i})^{-1}}$ where
$t_{i}$ is the necessary time for photons and gravitons with rest masses
$m_{ph}$ and $m_{g}$ to get the velocity equal the speed of light (in the
fractal Universe the moving with any velocities is possible), $t_{0}$ is the
time of existence of Universe. Under some assumption preliminary values of rest
masses photons and gravitons are obtained: for a rest mass of photons $
m_{f}\sim 10^{-39}g$, for a rest mass of gravitons $m_{g}\sim10^{-43}g$.


title: Quantum Entanglement and Quantum Chromodynamics

abstract:
  Non-locality or entanglement is an experimentally well established property
of quantum mechanics. Here we study the role of quantum entanglement for higher
symmetry group like $ SU(3_c) $, the gauge group of quantum chromodynamics
(QCD). We show that the hitherto unexplained property of confinement in QCD
arises as a fundamental feature of quantum entanglement in $ SU(3_c) $.


title: A Novel Approach to Structure Alignment

abstract:
  A novel approach for structure alignment is presented, where the key
ingredients are: (1) An error function formulation of the problem
simultaneously in terms of binary (Potts) assignment variables and real-valued
atomic coordinates. (2) Minimization of the error function by an iterative
method, where in each iteration a mean field method is employed for the
assignment variables and exact rotation/translation of atomic coordinates is
performed, weighted with the corresponding assignment variables. The approach
allows for extensive search of all possible alignments, including those
involving arbitrary permutations. The algorithm is implemented using a C_alpha
representation of the backbone and explored on different protein structure
categories using the Protein Data Bank (PDB) and is successfully compared with
other algorithms. The approach performs very well with modest CPU consumption
and is robust with respect to choice of parameters. It is extremely generic and
flexible and can handle additional user-prescribed constraints easily.
Furthermore, it allows for a probabilistic interpretation of the results.


title: Bessel Beams

abstract:
  Scalar Bessel beams are derived both via the wave equation and via
diffraction theory. While such beams have a group velocity that exceeds the
speed of light, this is a manifestation of the "scissors paradox" of special
relativty. The signal velocity of a modulated Bessel beam is less than the
speed of light. Forms of Bessel beams that satisfy Maxwell's equations are also
given.


title:
Estimating the K-function of a point process with an application to
  cosmology

abstract:
  Motivated by the study of an important data set for understanding the
large-scale structure of the universe, this work considers the estimation of
the reduced second moment function, or K-function, of a stationary point
process observed over a large number of segments of possibly varying lengths.
Theory and simulation are used to compare the behavior of isotropic and rigid
motion correction estimators and some modifications of these estimators. These
results generally support the use of modified versions of the rigid motion
correction. When applied to a catalog of astronomical objects known as
absorbers, the proposed methods confirm results from earlier analyses of the
absorber catalog showing clear evidence of clustering up to 50 Mpc and marginal
evidence for clustering of matter on spatial scales beyond 100 Mpc, which is
beyond the distance at which clustering of matter is now generally accepted to
exist.


title: Issues in Quantized Fractal Space Time

abstract:
  In recent years, the picture of discrete space time has been studied in the
context of stochastic theory. There are a number of ramifications, which are
briefly examined. We argue that the causality of physiics has its roots in the
analyticity within the two dimensons of a fractal quantum path and further show
how this picture has convergence wth quantum superstrings.


title: On Standard Model Higgs and Superstring Theories

abstract:
  It is shown that in the Standard Model, the property of charge quantization
holds for a Higgs with arbitrary isospin and hypercharge. These defining
quantum numbers of the Higgs remain unconstrained while the whole basic and
fundamental structure of the Standard Model remains intact. Hence it is shown
that the Higgs cannot be a physical particle. Higgs is the underlying `vacuum'
over which the whole edifice of the Standard Model stands. Also on most general
grounds it is established here that as per the Standard Model there is no
electric charge above the electro-weak phase transition temperature. Hence
there was no electric charge present in the Early Universe. The Superstring
Theories are flawed in as much as they are incompatible with this requirement.


title: Shuffling Yeast Gene Expression Data

abstract:
  A new method to sort gene expression patterns into functional groups is
presented. The method is based on a sorting algorithm using a non-local
similarity score, which takes all other patterns in the dataset into account.
The method is therefore very robust with respect to noise. Using the expression
data for yeast, we extract information about functional groups. Without prior
knowledge of parameters the cell cycle regulated genes in yeast can be
identified. Furthermore a second, independent cell clock is identified. The
capability of the algorithm to extract information about signal flow in the
regulatory network underlying the expression patterns is demonstrated.

categories: physics.bio-ph physics.data-an physics.med-ph q-bio.QM


title: Time and the laws of Nature

abstract:
  What is time? Why does it "flow" and why are we sure that it flows from past
towards future? Why is there such a gigantic distinction between the Past of
our world, which we believe to be fixed, and the Future, which we consider
undetermined? And this is in spite of the fact that almost all physical laws
are time-symmetric! Why does previously undetermined "Future" acquire its
steadiness as it passes the moment called "the Present"? Perhaps, these
questions are partially answered in the considerations below.


title: Schwarzschild's Curved Spacetime Lagrangian with Its Quantum Equations

abstract:
  From the curved spacetime Lagrangian the first approximation scalar particle
quantum equation was obtained following the canonical formalism. The roots of
this equation in Schwarzschild's pseudo flat space were found. As it was shown
in a more general curved spacetime it is tedious to find equation's roots. The
massless particle limiting case was considered. The Maxwell set of equations
generalized to Schwarzschild's space was reproduced.


title:
Multidimensional Mesh Approaches to Calculations of Atoms and Diatomic
  Molecules in Strong Electric Fields

abstract:
  Fully numerical mesh solutions of 2D and 3D quantum equations of Schroedinger
and Hartree-Fock type allow us to work with wavefunctions which possess a very
flexible geometry. This flexibility is especially important for calculations of
atoms and molecules in strong external fields where neither the external field
nor the internal interactions can be considered as a perturbation. In the
framework of this method we present various approaches to calculations of
quasi-steady states of these systems in strong electric fields. These
approaches are aimed at obtaining precise complex wavefunctions and
corresponding eigenvalues in the form E = E_0 - i\Gamma/2, where E_0 is the
real part of the energy and the value \Gamma/2 determines the lifetime of the
state in relation to escape of electrons from the system. The applications for
single-electron systems include correct solutions of the Schroedinger equation
for the H_2^+ ion (energies and decay rates) and the hydrogen atom in strong
parallel electric and magnetic fields. Some results for the helium atom in
strong electric fields are announced.


title: Expected behaviour of different semiconductor materials in hadron fields

abstract:
  The utilisation of semiconductor materials as detectors and devices operating
in high radiation environments, at the future particle colliders, in space
applications or in medicine and industry, necessitates to obtain radiation
harder materials. A systematic theoretical study has been performed,
investigating the interaction of charged hadrons with semiconductor materials
and the mechanisms of defect creation by irradiation. The mechanisms of the
primary interaction of the hadron with the nucleus of the semiconductor lattice
have been explicitly modelled and the Lindhard theory of the partition between
ionisation and displacements has been considered. The behaviour of silicon,
diamond, and some AIIIBV compounds, as GaAs, GaP, InP, InAs, InSb has been
investigated. The nuclear energy loss, and the concentration of primary defects
induced in the material bulk by the unit hadron fluence have been calculated.
The peculiarities of the proton and pion interactions as well as the specific
properties of the semiconductor material have been put in evidence.


title: Evolution: The Case of the Glyceraldehyde-3-Phosphate Dehydrogenase Gene

abstract:
  The enzyme Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) catalyses the
decomposition of glucose. The gene that produces the GAPDH is therefore present
in a wide class of organisms. We show that for this gene the average value of
the fluctuations in nucleotide distribution in the codons, normalized to strand
bias, provides a reasonable measure of how the gene has evolved in time.


title: Clebsch (String) Parameterization of 3-Vectors and Their Actions

abstract:
  We discuss some properties of the intrinsically nonlinear Clebsch
decomposition of a vector field into three scalars in d=3. In particular, we
note and account for the incompleteness of this parameterization when
attempting to use it in variational principles involving Maxwell and
Chern-Simons actions. Similarities with string decomposition of metrics and
their actions are also pointed out.

categories: physics.flu-dyn hep-th math-ph math.MP physics.gen-ph


title:
"Back-of-the-envelope" wind and altitude correction for 100 metre sprint
  times

abstract:
  A simple algebraic expression is presented to correct men's and women's 100
metre sprint times for ambient wind and altitude effects. The simplified
formula is derived from a more complicated equation of motion used to model the
athlete's velocity as a function of time (the velocity curve). This method
predicts adjustments to 0-wind and 0-altitude equivalents, which are in
excellent agreement to other estimates presented in the literature. The
expression is easily programmable on any computer, and could conveniently be
used by coaches, meet directors, or the media to assess the performance of
athletes and the quality of a race immediately following the event.


title:
Experimental evidence of dynamical localization and delocalization in a
  quasi-periodic driven system

abstract:
  This paper presents the first experimental evidence of the transition from
dynamical localization to delocalization under the influence of a
quasi-periodic driving on a quantum system. A quantum kicked rotator is
realized by placing cold atoms in a pulsed, far-detuned, standing wave. If the
standing wave is periodically pulsed, one observes the suppression of the
classical chaotic diffusion, i.e. dynamical localization. If the standing wave
is pulsed quasi-periodically with two different frequencies, dynamical
localization is observed or not, depending on the two frequencies being
commensurable or incommensurable. One can thus study the transition from the
localized to the delocalized case as a function of the effective dimensionality
of the system.


title:
Modeling study on the validity of a possibly simplified representation
  of proteins

abstract:
  The folding characteristics of sequences reduced with a possibly simplified
representation of five types of residues are shown to be similar to their
original ones with the natural set of residues (20 types or 20 letters). The
reduced sequences have a good foldability and fold to the same native structure
of their optimized original ones. A large ground state gap for the native
structure shows the thermodynamic stability of the reduced sequences. The
general validity of such a five-letter reduction is further studied via the
correlation between the reduced sequences and the original ones. As a
comparison, a reduction with two letters is found not to reproduce the native
structure of the original sequences due to its homopolymeric features.


title: Remote sensing of bubble clouds in seawater

abstract:
  We report on the influence of submerged bubble clouds on the remote sensing
properties of water. We show that the optical effect of bubbles on radiative
transfer and on the estimate of the ocean color is significant. We present a
global map of the volume fraction of air in water derived from daily wind speed
data. This map, together with the parameterization of the microphysical
properties, shows the possible significance of bubble clouds on the albedo of
incoming solar energy


title:
Monte Carlo study of the scattering error of a quartz reflective
  absorption tube

abstract:
  A Monte Carlo model was used to study the scattering error of an absorption
meter with a divergent light beam and a limited acceptance angle of the
receiver. Reflections at both ends of the tube were taken into account.
Calculations of the effect of varying optical properties of water, as well as
the receiver geometry, were performed. A weighting function showing the
scattering error quantitatively as a function of angle was introduced. Some
cases of the practical interests are discussed.


title: Symmetry Analysis Of Genetic Code And Determinative Degree (in Russian)

abstract:
  A three-dimensional model of the genetic vocabulary is proposed in terms of
determinative degree, an introduced characteristic of nucleotide, which
reflects absolute difference between purin and pyrimidin bases in one DNA
strand. In the fremework of this model manifest symmetry and group properties
are described. It is proposed to use the determinative degree of codons to
analyze genetic texts, and to explain the biological sense of various
functional regions of DNA.


title: Asymptotic light field in the presence of a bubble-layer

abstract:
  We report that the submerged microbubbles are an efficient source of diffuse
radiance and may contribute to a rapid transition to the diffuse asymptotic
regime. In this asymptotic regime an average cosine is easily predictable and
measurable.


title: Improvements of the Discrete Dipole Approximation method

abstract:
  The discrete-dipole approximation (DDA) is a flexible technique for computing
scattering and absorption by targets of arbitrary geometry. In this paper we
perform systematic study of various non-stationary iterative (conjugate
gradient) methods in search for the most efficient one in order to solve the
system of equations arising in DDA. We document implementation of these methods
in our public domain code DDSCAT.5a


title: Rhythmos, Diathige, Trope

abstract:
  It is argued that properties of Democritus' atoms parallel those of volume
forms in differential geometry. This kind of atoms has not "size" of finite
magnitude.
  -----
  Se arguye que las propiedades de los atomos de Democrito son paralelas a las
de sus formas de volumen en geometria diferencial. Este tipo de atomos no tiene
tamanno de magnitud finita.


title: Theory of coherent photoassociation of a Bose-Einstein condensate

abstract:
  We study coherent photoassociation, phenomena analogous to coherent optical
transients in few-level systems, which may take place in photoassociation of an
atomic Bose-Einstein condensate but not in a nondegenerate gas. We develop a
second-quantized Hamiltonian to describe photoassociation, and apply the
Hamiltonian both in the momentum representation and in the position
representation (field theory). Solution of the two-mode problem including only
one mode each for the atomic and molecular condensates displays analogs of Rabi
oscillations and rapid adiabatic passage. A classical version of the field
theory for atoms and molecules is used to demonstrate that, in the presence of
photoassociating light, a joint-atom molecule is unstable against growth of
density fluctuations. Experimental complications, including spontaneous
emission and unwanted "rogue" photodissociation from a photoassociated molecule
are analyzed. A two-color Raman scheme is studied as a method to set up an
effective two-mode scheme with reduced spontaneous emission losses. We discuss
photoassociation rates and photoassociation Rabi frequencies for high-lying
vibrational states in alkalis both on the basis of molecular-structure
calculations, and by comparing with an experiment [Wynar et al., Science 287,
1016 (2000)].

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


title: Radial Viscous Flow between Two Parallel Annular Plates

abstract:
  An analytic solution to the linearized Navier-Stokes equation is given that
describes the radial flow of an incompressible, viscous fluid between two
parallel, concentric annular plates.


title:
Enhanced Pitch Angle Diffusion due to Electron-Whistler Interactions
  during Disturbed Times

abstract:
  During periods of increased magnetospheric activity, whistler wave emissions
have been observed with increased wave amplitudes. We consider a pitch angle
diffusion mechanism that is shown to scale with whistler wave amplitude and
hence is 'switched on' during these periods of intense activity.
  We consider the interaction between relativistic electrons and two oppositely
directed, parallel propagating whistler mode waves. We show that for intense
whistlers this process is stochastic and results in strong electron pitch angle
diffusion.
  We show that the interaction is rapid, occur on timescales of the order of
tens of electron gyroperiods and that the interaction is sensitive to wave
amplitude, wave frequency and electron energy.


title:
On the integration accuracy in molecular density functional theory
  calculations using Gaussian basis sets

abstract:
  The sensitivity of computed DFT (Density Functional Theory) molecular
properties (including energetics, geometries, vibrational frequencies, and
infrared intensities) to the radial and angular numerical integration grid
meshes, as well as to the partitioning scheme, is discussed for a number of
molecules using the Gaussian 98 program system. Problems with typical
production grid sizes are particularly acute for third-row transition metal
systems, but may still result in qualitatively incorrect results for a molecule
as simple as CCH. Practical recommendations are made with respect to grid
choices for the energy(+gradient) steps, as well as for the solution of the
CPKS (Coupled Perturbed Kohn-Sham) equations.


title: A General Symbolic Method with Physical Applications

abstract:
  A solution to the problem of unifying the General Relativistic and Quantum
Theoretical formalisms is given which introduces a new non-axiomatic symbolic
method and an algebraic generalization of the Calculus to non-finite symbolisms
without reference to the concept of a limit.
  An essential feature of the non-axiomatic method is the inadequacy of any
(finite) statements: Identifying this aspect of the theory with the "existence
of an external physical reality" both allows for the consistency of the method
with the results of experiments and avoids the so-called "measurement problem"
of quantum theory.


title: Time series model based on global structure of complete genome

abstract:
  A time series model based on the global structure of the complete genome is
proposed. Three kinds of length sequences of the complete genome are
considered. The correlation dimensions and Hurst exponents of the length
sequences are calculated. Using these two exponents, some interesting results
related to the problem of classification and evolution relationship of bacteria
are obtained.


title: On the role of mass growth in dusty plasma kinetics

abstract:
  It is shown that absorption of ions by the dust grain may reduce the
effective translational temperature of the dust component below the ambient gas
temperature.


title:
Work performed by a Classical-"reversible"-Carnot cycle: Raising's
  distribution for the small "driving weights"

abstract:
  The expansions or the compressions of the ideal gas in the quasi-static
Carnot cycle, can be performed (on adiabatic or isothermal way) by slowly
increasing or decreasing the external pressure by means of small weights acting
on the piston of the vessel containing the gas. We call them shortly the
``driving weights'' (dw). Let N be their number, a large one.
  To determine the work performed by the ideal gas in the cycle the ``driving
weights'' must be handled carefully. If we let them move on-off the piston only
horizontally, their vertical motions will be due only to the gas. Here we show
that, at the end, while some of them will have moved down (will have negative
raising) the remaining ones (the majority) will have moved up (will have
positive raising) so that the total work performed by the ideal gas equals the
total variation of the gravitational potential energy of the ``driving
weghts''.
  The cycle is performed in 2N time-steps. For each step t_i, with i in
1,..,2N, we give H(t_i), and DH(t_{i-1},t_i), respectively the height and the
raising of the piston. Moreover the overall raising of the individual dw's
(i.e. h_k, with k in 1...N), and their distribution are given in simple,
general cases. The efficiency and the dissipated work are also evaluated.
  This paper is aimed at imparting a deeper understanding of the ideal Carnot
Engine and may also be useful as a segment in a didactic path on elementary
calculus and statistics.


title: Charging kinetics of dust particles with a variable mass

abstract:
  A kinetic equation for dust particles with a new kinetic variable - the mass
of grains - is suggested for the description of processes with changing mass in
dusty plasmas and neutral systems.


title: A mechanical model that exhibits a gravitational critical radius

abstract:
  Circular orbits of a particle sliding on a frictionless surface of revolution
about a vertical axis are unstable below a critical radius if the curvature of
the surface satisfies a specified condition. This behavior can be realized in a
mechanical model, which give a glimpse of the greater complexity of particle
orbits in curved rather than flat spacetime.


title: Radiometric force in dusty plasmas

abstract:
  A radiofrequency glow discharge plasma, which is polluted with a certain
number of dusty grains, is studied. In addition to various dusty plasma
phenomena, several specific colloidal effects should be considered. We focus on
radiometric forces, which are caused by inhomogeneous temperature distribution.
Aside from thermophoresis, the role of temperature distribution in dusty
plasmas is an open question. It is shown that inhomogeneous heating of the
grain by ion flows results in a new photophoresis like force, which is specific
for dusty discharges. This radiometric force can be observable under conditions
of recent microgravity experiments.


title: Upgrade of the PEP-II Low Beta Optics

abstract:
  The successful commissioning and operation of the PEP-II asymmetric e+e-
collider motivated further studies to increase luminosity. In this paper, we
discuss a modification of the PEP-II lattice to reduce the vertical beta
function at the Interaction Point (IP) from the design value of 1.5cm to 1.0cm.
This could potentially reduce the colliding beam size, increase particle
density at the IP and the probability of beam-beam interactions. In this paper,
we outline the optics modifications, discuss tracking simulations, and overview
machine implementation.


title: Role of Bose enhancement in photoassociation

abstract:
  We discuss the role of Bose enhancement of the dipole matrix element in
photoassociation, using stimulated Raman adiabatic passage as an example. In a
nondegenerate gas the time scale for coherent optical transients tends to
infinity in the thermodynamic limit, whereas Bose enhancement keeps this time
scale finite in a condensate. Coherent transients are therefore absent in
photoassociation of a thermal nondegenerate gas, but are feasible if the gas is
a condensate.


title:
Correlation property of length sequences based on global structure of
  complete genome

abstract:
  This paper considers three kinds of length sequences of the complete genome.
Detrended fluctuation analysis, spectral analysis, and the mean distance
spanned within time $L$ are used to discuss the correlation property of these
sequences. The values of the exponents from these methods of these three kinds
of length sequences of bacteria indicate that the long-range correlations exist
in most of these sequences. The correlation have a rich variety of behaviours
including the presence of anti-correlations. Further more, using the exponent
$\gamma$, it is found that these correlations are all linear ($\gamma=1.0\pm
0.03$). It is also found that these sequences exhibit $1/f$ noise in some
interval of frequency ($f>1$). The length of this interval of frequency depends
on the length of the sequence. The shape of the periodogram in $f>1$ exhibits
some periodicity. The period seems to depend on the length and the complexity
of the length sequence.


abstract:
  A time series model of CDS sequences in complete genome is proposed.
  A map of DNA sequence to integer sequence is given. The correlation
dimensions and Hurst exponents of CDS sequences in complete genome of bacteria
are calculated. Using the average of correlation dimensions, some interesting
results are obtained.


title:
Synchronisation, binding and the role of correlated firing in fast
  information transmission

abstract:
  Does synchronization between action potentials from different neurons in the
visual system play a substantial role in solving the binding problem? The
binding problem can be studied quantitatively in the broader framework of the
information contained in neural spike trains about some external correlate,
which in this case is object configurations in the visual field. We approach
this problem by using a mathematical formalism that quantifies the impact of
correlated firing in short time scales. Using a power series expansion, the
mutual information an ensemble of neurons conveys about external stimuli is
broken down into firing rate and correlation components. This leads to a new
quantification procedure directly applicable to simultaneous multiple neuron
recordings. It theoretically constrains the neural code, showing that
correlations contribute less significantly than firing rates to rapid
information processing. By using this approach to study the limits upon the
amount of information that an ideal observer is able to extract from a
synchrony code, it may be possible to determine whether the available amount of
information is sufficient to support computational processes such as feature
binding.


title: Higher Order Force Gradient Symplectic Algorithms

abstract:
  We show that a recently discovered fourth order symplectic algorithm, which
requires one evaluation of force gradient in addition to three evaluations of
the force, when iterated to higher order, yielded algorithms that are far
superior to similarly iterated higher order algorithms based on the standard
Forest-Ruth algorithm. We gauge the accuracy of each algorithm by comparing the
step-size independent error functions associated with energy conservation and
the rotation of the Laplace-Runge-Lenz vector when solving a highly eccentric
Kepler problem. For orders 6, 8, 10 and 12, the new algorithms are
approximately a factor of $10^3$, $10^4$, $10^4$ and $10^5$ better.


title: A new Loan-Stock Financial Instrument

abstract:
  A new financial instrument (a new kind of a loan) is introduced. The
loan-stock instrument (LSI) combines fixed rate instruments (loans, etc.) with
other financial instruments that have higher volatilities and returns (stocks,
mutual funds, currencies, derivatives, options, etc.). This new loan depends on
the value of underlying security (for example, stock) in such a way that when
underlying security increases, the value of loan decreases and backwards. The
procedure to create a risk free portfolio and a technique to fairly price the
LSI is described. The philosophy behind this procedure is quite similar to the
Black-Scholes formalism in option theory. Creation of the risk free portfolio
is possible because the change in the underlying security offsets the change in
the value of the loan (or the amount that the borrower has to repay). The new
financial instrument takes an advantage of the fact that on average the stock
market grows in time. It is beneficial for both the borrower and the lender.
The LSI is more attractive for the borrower than the traditional loan is due to
the decrease in the amount that has to be repaid. This attractiveness
constitutes the benefit for the lender in terms of the market share among the
borrowers. In addition, the lender can charge the extra premium.


title: Sub-dekahertz ultraviolet spectroscopy of 199Hg+

abstract:
  Using a laser that is frequency-locked to a Fabry-Perot etalon of high
finesse and stability, we probe the 5d10 6s 2S_1/2 (F=0) - 5d9 6s 2D_5/2 (F=2)
Delta-m_F = 0 electric-quadrupole transition of a single laser-cooled 199Hg+
ion stored in a cryogenic radio-frequency ion trap. We observe
Fourier-transform limited linewidths as narrow as 6.7 Hz at 282 nm (1.06 X
10^15 Hz), yielding a line Q = 1.6 X 10^14. We perform a preliminary
measurement of the 5d9 6s2 2D_5/2 electric-quadrupole shift due to interaction
with the static fields of the trap, and discuss the implications for future
trapped-ion optical frequency standards.


title: General relativity as a complete theory and its new consequences

abstract:
  The strong proper time dilation and radial contraction in the gravitational
field of compact sources leads to a frozen state of matter. It is shown that
the falling particles and photons can not cross the gravitational radius due to
the freezing, the horizon and singularity can not be formed at any finite
coordinate time moment t=const. As the result, general relativity really
predicts the heavy baryonic and quark stars and quasars instead of the black
holes. A model of the oscillating Universe without a cosmological singularity,
having a new type of the cosmological redshift, is considered. The
regularizations of loop divergencies in quantum field theory also can be
explained as the gravitational effects.


title: Spectroscopic electric-field measurement in laser-excited plasmas

abstract:
  The electric field in mm-sized clouds of cold Rb^+-ions is measured using the
Stark effect of Rydberg atoms embedded in the ion clouds. The ion clouds are
produced by UV photoionization of laser-cooled rubidium atoms in a
magneto-optic trap. In very dense ion clouds, the Rydberg atom excitation
spectra reflect the presence of a neutral plasma core and a positively charged
ion shell.


title:
Comment on ``Air bubbles in water: A strongly multiple scattering medium
  for acoustic waves" [Phys. Rev. Lett. 84, 6050, 2000]

abstract:
  We comment on a recent Letter in Phys. Rev. Lett. (M. Kafesaki, R. S. Penciu,
and E. N. Economou, Phys. Rev. Lett. {\bf 84}, 6050 (2000))


title:
Instantaneous response of the ionosphere to a sudden commencement of the
  strong magnetic storm of April 6, 2000

abstract:
  We developed a new technology for global detection of atmospheric
disturbances, on the basis of phase measurements of the total electron content
(TEC) using an international GPS networks. Temporal dependencies of TEC are
obtained for a set of spaced receivers of the GPS network simultaneously for
the entire set of visible satellites. These series are subjected to filtering
in the selected range of oscillation periods using known algorithms for
spatio-temporal analysis of signals. An "instantaneous" ionospheric response to
the sudden commencement of a strong magnetic storm of April 6, 2000 was
detected. On the dayside of the Earth the largest value of the net response
amplitude was found to be of order 0.8*10^16 m^-2 (1--2 % of the background TEC
value), and the delay with respect to the SC in mid-latitudes was about 200 s.
In higher latitudes the delay goes as long as 15 min. On the nightside these
values are 0.2*10^16 m^-2 and 30 min, respectively. The velocity of the
traveling disturbance from the middle to high latitudes on the dayside as well
as from the dayside to the nightside was about 10-20 km/s.


title:
Inertial waves in a rotating spherical shell: attractors and asymptotic
  spectrum

abstract:
  We investigate the asymptotic properties of inertial modes confined in a
spherical shell when viscosity tends to zero. We first consider the mapping
made by the characteristics of the hyperbolic equation (Poincar\'e's equation)
satisfied by inviscid solutions. Characteristics are straight lines in a
meridional section of the shell, and the mapping shows that, generically, these
lines converge towards a periodic orbit which acts like an attractor.
  We then examine the relation between this characteristic path and
eigensolutions of the inviscid problem and show that in a purely
two-dimensional problem, convergence towards an attractor means that the
associated velocity field is not square-integrable. We give arguments which
generalize this result to three dimensions. We then consider the viscous
problem and show how viscosity transforms singularities into internal shear
layers which in general betray an attractor expected at the eigenfrequency of
the mode. We find that there are nested layers, the thinnest and most internal
layer scaling with $E^{1/3}$-scale, $E$ being the Ekman number. Using an
inertial wave packet traveling around an attractor, we give a lower bound on
the thickness of shear layers and show how eigenfrequencies can be computed in
principle. Finally, we show that as viscosity decreases, eigenfrequencies tend
towards a set of values which is not dense in $[0,2\Omega]$, contrary to the
case of the full sphere ($\Omega$ is the angular velocity of the system).
Hence, our geometrical approach opens the possibility of describing the
eigenmodes and eigenvalues for astrophysical/geophysical Ekman numbers
($10^{-10}-10^{-20}$), which are out of reach numerically, and this for a wide
class of containers.

categories: physics.flu-dyn astro-ph cond-mat nlin.PS


title: Prediction of long term stability by extrapolation

abstract:
  This paper studies the possibility of using the survival function to predict
long term stability by extrapolation. The survival function is a function of
the initial coordinates and is the number of turns a particle will survive for
a given set of initial coordinates. To determine the difficulties in
extrapolating the survival function, tracking studies were done to compute the
survival function. The survival function was found to have two properties that
may cause difficulties in extrapolating the survival function. One is the
existence of rapid oscillations, and the second is the existence of plateaus.
It was found that it appears possible to extrapolate the survival function to
estimate long term stability by taking the two difficulties into account. A
model is proposed which pictures the survival function to be a series of
plateaus with rapid oscillations superimposed on the plateaus. The tracking
studies give results for the widths of these plateaus and for the seperation
between adjacent plateaus which can be used to extrapolate and estimate the
location of plateaus that indicate survival for longer times than can be found
by tracking.


title:
A Review Essay: "Lise Meitner and the Dawn of the Nuclear Age", by
  Patricia Rife

abstract:
  The recently published book, ``Lise Meitner and the Dawn of the Nuclear
Age'', by Patricia Rife (Boston: Birkh\"{a}user, 1999) is reviewed in an essay
for the lay audience. Meitner was a leading nuclear physicist at the time that
the nucleus was the most exciting frontier of science. To establish her career,
she had to overcome daunting prejudices against women in science and academia.
Being of Jewish origin in Germany in the 1930's, she narrowly escaped certain
disaster. Meitner was a crucial participant in the discovery of nuclear
fission, yet did not share in the Nobel Prize that her collaborator, Otto Hahn,
received in 1945. How these events came about, how they were intertwined with
contemporary history and how they fit into the evolution of Meitner's social
conscience and her abhorrence of war are some of the fascinating subjects
discussed in the book and reviewed in this essay.


title:
Slow inviscid flows of a compressible fluid in spatially inhomogeneous
  systems

abstract:
  An ideal compressible fluid is considered, with an equilibrium density being
a given function of coordinates due to presence of some static external forces.
The slow flows in such system, which do not disturb the density, are
investigated with the help of the Hamiltonian formalism. The equations of
motion of the system are derived for an arbitrary given topology of the
vorticity field. The general form of the Lagrangian for frozen-in vortex lines
is established. The local induction approximation for motion of slender vortex
filaments in several inhomogeneous physical models is studied.


title:
Theoretical calculations of the primary defects induced by pions and
  protons in SiC

abstract:
  In the present work, the bulk degradation of SiC in hadron (pion and proton)
fields, in the energy range between 100 MeV and 10 GeV, is characterised
theoretically by means of the concentration of primary defects per unit
fluence. The results are compared to the similar ones corresponding to diamond,
silicon and GaAs.


title: The general relativistic theory of quasars

abstract:
  The paper was a preliminary and rejected by the author attempt to describe
compact relativistic objects.


title: Beam Current Monitors in the Nlcta

abstract:
  The current profile along the 126 ns, multi-bunch beam pulse in the Next
Linear Collider Test Accelerator (NLCTA) is monitored with fast toroids (rise
time ~1 ns). Inserted at several positions along the beam line, they allow us
to track current transmission as a function of position along the bunch train.
Various measurements, such as rise time, current, width, and slope, are made on
the digitized signals, which can be corrected in software by means of stored
frequency response files. The design and implementation of these devices is
described.


title: Beam Profile Monitors in the Nlcta

abstract:
  The transverse current profile in the Next Linear Collider Test Accelerator
(NLCTA) electron beam can be monitored at several locations along the beam line
by means of profile monitors. These consist of insertable phosphor screens,
light collection and transport systems, CID cameras, a frame-grabber, and PC
and VAX based image analysis software. In addition to their usefulness in
tuning and steering the accelerator, the profile monitors are utilized for
emittance measurement. A description of these systems and their performance is
presented.


title:
Improved efficiency with variational Monte Carlo using two level
  sampling

abstract:
  A two level sampling method is applied to variational Monte Carlo (VMC) that
samples the one and two body parts of the wave function separately. The method
is demonstrated on a single Li_2 molecule in free space and 32 H_2 molecules in
a periodic box. This simple modification increases the efficiency of a VMC
simulation by up to 72%.


title: Effective ATI Channels in High Harmonic Generation

abstract:
  Harmonic generation by an atom in a laser field is described by the
three-step mechanism as proceeding via above-threshold ionization (ATI)
followed by the electron propagation in the laser-dressed continuum and the
subsequent laser assisted recombination (LAR). An amplitude of harmonic
production is given by the coherent sum of contributions from different
intermediate ATI channels labeled by the number m of absorbed laser photons.
The range of m-values that gives substantial contribution is explored and found
to be rather broad for high harmonic generation. The coherence effects are of
crucial importance being responsible for the characteristic pattern of harmonic
intensities with a plateau domain followed by a cutoff region. Due to
multiphoton nature of the process, an efficient summation of m-contributions
can be carried out in the framework of the saddle point method. The saddle
points correspond to some complex-valued labels m=m_c associated with the
intermediate effective ATI channels in the three-step harmonic generation
process. The advantage of this approach stems from the fact that summation over
large number of conventional ATI m-channels is replaced by summation over small
number of effective m_c-channels. The equation governing m_c has a transparent
physical meaning: the electron ejected from the atom on the first (ATI) stage
should return to the core to make LAR possible. The calculated rates are in
good agreement with the results obtained by other approaches.


title:
Equations for Stochastic Macromolecular Mechanics of Single Proteins:
  Equilibrium Fluctuations, Transient Kinetics and Nonequilibrium Steady-State

abstract:
  A modeling framework for the internal conformational dynamics and external
mechanical movement of single biological macromolecules in aqueous solution at
constant temperature is developed. Both the internal dynamics and external
movement are stochastic; the former is represented by a master equation for a
set of discrete states, and the latter is described by a continuous
Smoluchowski equation. Combining these two equations into one, a comprehensive
theory for the Brownian dynamics and statistical thermodynamics of single
macromolecules arises. This approach is shown to have wide applications. It is
applied to protein-ligand dissociation under external force, unfolding of
polyglobular proteins under extension, movement along linear tracks of motor
proteins against load, and enzyme catalysis by single fluctuating proteins. As
a generalization of the classic polymer theory, the dynamic equation is capable
of characterizing a single macromolecule in aqueous solution, in probabilistic
terms, (1) its thermodynamic equilibrium with fluctuations, (2) transient
relaxation kinetics, and most importantly and novel (3) nonequilibrium
steady-state with heat dissipation. A reversibility condition which guarantees
an equilibrium solution and its thermodynamic stability is established, an
H-theorem like inequality for irreversibility is obtained, and a rule for
thermodynamic consistency in chemically pumped nonequilibrium steady-state is
given.


title: Ionic and electronic structure of sodium clusters up to N=59

abstract:
  We determined the ionic and electronic structure of sodium clusters with even
electron numbers and 2 to 59 atoms in axially averaged and three-dimensional
density functional calculations. A local, phenomenological pseudopotential that
reproduces important bulk and atomic properties and facilitates structure
calculations has been developed. Photoabsorption spectra have been calculated
for $\mathrm{Na}_2$, $\mathrm{Na}_8$, and $\mathrm{Na}_9^+$ to
$\mathrm{Na}_{59}^+$. The consistent inclusion of ionic structure considerably
improves agreement with experiment. An icosahedral growth pattern is observed
for $\mathrm{Na}_{19}^+$ to $\mathrm{Na}_{59}^+$. This finding is supported by
photoabsorption data.


title: Symmetries of Optical Phase Conjugation

abstract:
  Various algebraic structures of degenerate four-wave mixing equations of
optical phase conjugation are analyzed. Two approaches (the spinorial and the
Lax-pair based), complementary to each other, are utilized for a systematic
derivation of conserved quantities. Symmetry groups of both the equations and
the conserved quantities are determined, and the corresponding generators are
written down explicitly. Relation between these two symmetry groups is found.
Conserved quantities enable the introduction of new methods for integration of
the equations in the cases when the coupling $\Gamma$ is either purely real or
purely imaginary. These methods allow for both geometries of the process,
namely the transmission and the reflection, to be treated on an equal basis.
One approach to introduction of Hamiltonian and Lagrangian structures for the
4WM systems is explored, and the obstacles in successful implementation of that
programe are identified. In case of real coupling these obstacles are
removable, and full Hamiltonian and Lagrangian formulations of the initial
system are possible.


title: Black Holes From Different Perspectives

abstract:
  In this paper we consider black holes from a non general relativistic
perspective as also from a microphysical point of view.


title:
The Unification of Electromagnetism and Gravitation in the Context of
  Quantized Fractal Space Time

abstract:
  The attempts to unify electromagnetism and gravitation have included the
formulations of Herman Weyl and the Kaluza Klein theory with the fifth
dimension. More recently there have been fruitful attempts in the domain of
Quantum Superstrings and the author's formulation in terms of Quantum
Mechanical Kerr-Newman Black Holes. Though all these appear to be widely
divergent approaches, they are shown to have a unified underpinning in the
context of quantized fractal space time.


title:
Classical Radiation Reaction Off-Shell Corrections to the Covariant
  Lorentz Force

abstract:
  It has been shown by Gupta and Padmanabhan that the radiation reaction force
of the Abraham-Lorentz-Dirac equation can be obtained by a coordinate
transformation from the inertial frame of an accelerating charged particle to
that of the laboratory. We show that the problem may be formulated in a flat
space of five dimensions, with five corresponding gauge fields in the framework
of the classical version of a fully gauge covariant form of the Stueckelberg-
Feynman-Schwinger covariant mechanics (the zero mode fields of the 0,1,2,3
components correspond to the Maxwell fields). Without additional constraints,
the particles and fields are not confined to their mass shells. We show that in
the mass-shell limit, the generalized Lorentz force obtained by means of the
retarded Green's functions for the five-dimensional field equations provides
the classical Abraham-Lorentz-Dirac radiation reaction terms (with renormalized
mass and charge). We also obtain general coupled equations for the orbit and
the off-shell dynamical mass during the evolution. The theory does not admit
radiation if the particle remains identically on-shell. The structure of the
equations implies that the mass-shell deviaiton is bounded when the external
field is removed.


title: Lamb Shift of 3P and 4P states and the determination of $\alpha$

abstract:
  The fine structure interval of P states in hydrogenlike systems can be
determined theoretically with high precision, because the energy levels of P
states are only slightly influenced by the structure of the nucleus. Therefore
a measurement of the fine structure may serve as an excellent test of QED in
bound systems or alternatively as a means of determining the fine structure
constant $\alpha$ with very high precision. In this paper an improved analytic
calculation of higher-order binding corrections to the one-loop self energy of
3P and 4P states in hydrogen-like systems with low nuclear charge number $Z$ is
presented. A comparison of the analytic results to the extrapolated numerical
data for high $Z$ ions serves as an independent test of the analytic
evaluation. New theoretical values for the Lamb shift of the P states and for
the fine structure splittings are given.


title:
Effects of the August 11, 1999 total solar eclipse as deduced from total
  electron content measurements at the GPS network

abstract:
  We present the results derived from measuring fundamental parameters of the
ionospheric response to the August 11, 1999 total solar eclipse. Our study is
based on using the data from about 70 GPS stations located in the neighbourhood
of the eclipse totality phase in Europe. The eclipse period was characterized
by a low level of geomagnetic disturbance (Dst - variation from -10 to -20 nT),
which alleviated significantly the problem of detecting the ionospheric
response to the eclipse. Our analysis revealed a well-defined effect of a
decrease (depression) of the total electron content (TEC) for all GPS stations.
The delay between minimum TEC values with respect to the totality phase near
the eclipse path increased gradually from 4 min in Greenwich longitude (10:40
UT, LT) to 8 min at the longitude 16 degrees (12:09 LT). The depth and duration
of the TEC depression were found to be 0.2-0.3 TECU and 60 min, respectively.
The results obtained in this study are in good agreement with earlier
measurements and theoretical estimates.


title:
Basic Constituents of the Visible and Invisible Matter - A Microscopic
  View of the Universe

abstract:
  One of the greatest achievements of twentieth century physics is the
discovery of a very close link between the microcosm and the macrocosm. This
follows from the two basic principles of quantum mechanics and relativity, the
uncertainty principle and the mass energy equivalence, along with the standard
big bang model of cosmology. As we probe deeper into the microcosm we encounter
states of higher mass and energy, which were associated with the early history
of the universe. Thus discovery of the atomic nucleus followed by the nuclear
particles, quarks & gluons and finally the $W$ & $Z$ bosons have recreated in
the laboratory the forms of matter that abounded in the very early universe.
This has helped us to trace back the history of the universe to within a few
picoseconds of its creation. Finally the discovery of the Higgs and
supersymmetric particles will help to solve the mystry of the invisible matter,
which abound throughout the universe today, as relics of that early history.


title: The GPS global detection of the ionospheric response to solar flares

abstract:
  This author suggests the concept of a new technology for global detection
(GLOBDET) of atmospheric disturbances of natural and technogenic origin, on the
basis of phase measurements of the total electron content (TEC) in the
ionosphere using an international GPS network. Temporal dependencies of TEC are
obtained for a set of spaced receivers of the GPS network simultaneously for
the entire set of "visible" (over a given time interval) GPS satellites (up to
5-10 satellites). These series are subjected to filtering in the selected range
of oscillation periods using algorithms for spatio-temporal analysis of signals
of non-equidistant GPS phased antenna arrays which are adequate to the detected
disturbance. An analysis is made of the possibilities of using the GLOBDET when
detecting the ionospheric response of solar flares. In this case it is best to
make the coherent summation of the filtered series of TEC. A powerful impulsive
flares of July 29, 1999 and December 28, 1999 were chosen to illustrate the
practical implementation of the proposed method.


title: It is the ambiguity. (But only three generations)

abstract:
  It is suggested that generations are linked to the need of calculating
curvature of space via a deformed or discrete calculus. Quantization would
limit the deformation, building three generations, and not four, as other
interpretation could imply.


title: The Proposed NLC Linac LLRF System

abstract:
  The proposed Next Linear Collider (NLC) contains linac systems operating at
L,S,C, and X band. This paper describes a wideband modular low-level RF (LLRF)
system applicable for all NLC pulsed RF systems. High speed digital IF
techniques are used for both arbitrary klystron drive modulation and accurate
RF vector detection. Measurement of relative beam to RF phase, beam loading
compensation, and structure dipole modes for automated alignment are all
handled by the system. Modern signal processing techniques are also described.


title: Experience with the Pep-II RF System at High Beam Currents

abstract:
  The PEP-II B Factory Low-Level RF System (LLRF) is a fully programmable VXI
based design running under an EPICS control environment. Several RF feedback
loops are used to control longitudinal coupled-bunch modes driven by the
accelerating mode of the RF cavities. This paper updates the performance of the
LLRF system as beam currents reach design levels. Modifications which enhance
the stability, diagnostics, and overall operational performance are described.
Recent data from high current operation is included.


title:
True Transformations of Spacetime Lengths and Apparent Transformations
  of Spatial and Temporal Distances. I. the Theory

abstract:
  It is shown in this paper that the difference between the two forms of
relativity - the ''true transformation (TT) relativity'' and - the ''apparent
transformation (AT) relativity'' is essentially caused by the difference in the
concept of \emph{sameness} of a physical system, i.e., of a physical quantity,
for different, relatively moving, observers. In the ''TT relativity'' the same
quantity for different inertial frames of reference is covariantly defined
four-dimensional (4D) tensor quantity, which transforms according to the
Lorentz transformation as the TT. In the ''AT relativity'' parts of a 4D tensor
quantity are often considered as the same quantity for different observers,
although they correspond to different quantities in 4D spacetime, and they are
not connected by the Lorentz transformation than by the AT. Then the true
transformations of a spacetime length and the apparent transformations of a
spatial distance (the Lorentz contraction) and of a temporal distance (the
usual dilatation of time) are examined in detail. It is proved that only the
true transformations of the spacetime length are in agreement with the special
relativity as the theory of a 4D spacetime with the pseudo-Euclidean geometry.


title:
True Transformations of Spacetime Lengths and Apparent Transformations
  of Spatial and Temporal Distances. II. the Comparison with Experiments

abstract:
  Some of the well-known experiments: the ''muon'' experiment, the
Michelson-Morley type experiments, the Kennedy-Thorndike type experiments and
the Ives-Stilwell type experiments are analyzed using the nonrelativistic
theory, the ''apparent transformations (AT) relativity'' and the ''true
transformations (TT) relativity.'' It is shown that all the experiments (when
they are complete from the ''TT relativity'' viewpoint) are in agreement with
the ''TT relativity'' in which the special relativity is understood as the
theory of a four-dimensional spacetime with the pseudo-Euclidean geometry. It
is also explicitly shown that, in contrast to the usual opinion, the commonly
used ''AT relativity'' does not always agree with experiments. The concept of
sameness of a physical quantity is essential for the distinction between the
two forms of relativity both in the theory and in experiments. The difference
in this concept causes the agreement of the ''TT relativity'' with the
experiments and the disagreement of the ''AT relativity.''


title:
Chapman's model for ozone concentration: earth`s slowing rotation effect
  in the atmospheric past

abstract:
  Chapman's model for ozone concentration is studied. In this nonlinear model,
the photodissociation coefficients for $O_{2}$ and $O_{3}$ are time-depending
due to earth-rotation. From the Kapitsa's method, valid in the high frequency
limit, we find the criterion for the existence of equilibrium solutions. These
solutions are depending on the frequency, and require a rotation period $T$
which satisfies $T<T_{1}$ or $T>T_{2}$. Where the critical periods $T_{1}$ and
$T_{2}$, with $T_{2}>T_{1}$, are a function of the parameters of the system
(reaction rates and photodissociation coefficients). Conjectures respect to the
retardation of the earth's rotation, due to friction, suggest that the
criterion was not even verified in the atmospheric past.


title:
The Channel Capacity of a Fiber Optics Communication System:
  perturbation theory

abstract:
  We consider the communication channel given by a fiber optical transmission
line. We develop a method to perturbatively calculate the information capacity
of a nonlinear channel, given the corresponding evolution equation. Using this
technique, we compute the decrease of the channel capacity to the leading order
in the perturbative parameter for fiber optics communication systems.

categories: physics.optics astro-ph cond-mat nlin.CD


title:
Theoretical prevision of physical chemical properties of amino acids
  from genetic code

abstract:
  Using the crystal basis model of the genetic code, a set of relations between
the physical-chemical properties of the amino acids are derived and compared
with the experimental data. A prevision for the not yet measured
thermodynamical parameters of three amino acids is done.


title:
Temperature of the SN1987A supernova provides an estimate of the
  electron neutrino mass

abstract:
  Numerous estimates of upper bounds on the (anti)neutrino rest mass have been
published based on the SN1987A observations.
  Here, we use a nonkinematic (thermal) time extent to provide a rest mass
estimate of a few eV (as mc^2 mass), if not zero. In the solution, we find that
a typical upper bound formula for the mass implies that this thermal extent was
attributable to about 10% of the particle energy measured on Earth. The present
approach yields an expected value for the mass, given any theoretical or model
dependent estimate of the fraction of the detected neutrino energy attributable
to the supernova temperature.


title:
Ionospheric effects of the solar flares of September 23, 1998 and July
  29, 1999 as deduced from global GPS network data

abstract:
  This paper presents data from first GPS measurements of global response of
the ionosphere to solar flares of September 23, 1998 and July 29, 1999. The
analysis used novel technology of a global detection of ionospheric effects
from solar flares (GLOBDET) as developed by one of the authors (Afraimovich E.
L.). The essence of the method is that use is made of appropriate filtering and
a coherent processing of variations in total electron content (TEC) in the
ionosphere which is determined from GPS data, simultaneously for the entire set
of visible (over a given time interval) GPS satellites at all stations used in
the analysis. It was found that fluctuations of TEC, obtained by removing the
linear trend of TEC with a time window of about 5 min, are coherent for all
stations and beams to the GPS satellites on the dayside of the Earth. The time
profile of TEC responses is similar to the time behavior of hard X-ray emission
variations during flares in the energy range 25-35 keV if the relaxation time
of electron density disturbances in the ionosphere of order 50-100 s is
introduced. No such effect on the nightside of the Earth has been detected yet.


title:
A new regime of anomalous penetration of relativistically strong laser
  radiation into an overdense plasma

abstract:
  It is shown that penetration of relativistically intense laser light into an
overdense plasma, accessible by self-induced transparency, occurs over a finite
length only. The penetration length depends crucially on the overdense plasma
parameter and increases with increasing incident intensity after exceeding the
threshold for self-induced transparency. Exact analytical solutions describing
the plasma-field distributions are presented.


title: Continuation of the Fermion-Number Operator and the Puzzle of Families

abstract:
  An "analytic continuation" of a Hermitian matrix representing the
conventional fermion-number operator, leads to a new, and unconventional,
internal description of quarks and leptons. This phenomenological description,
unlike the conventional standard-model description, is capable of explaining,
among other things, why there are just three families of quarks and leptons.
These facts provide indirect evidence that the analytic continuation in
question somehow reflects physics at the Planck level where flavor
degrees-of-freedom presumably originate.


title: Topological Constraints on Long-Distance Neutrino Mixtures

abstract:
  A new internal description of fundamental fermions (quarks and leptons),
based on a matrix-generalization (F) of the scalar fermion-number f, predicts
that only three families of quarks and leptons, and their associated neutrinos
(nu_e, nu_mu and nu_tau), exist. Moreover, this description places important
topological constraints on neutrino mixing. For example, with respect to F, the
topology of the nu_e (nu_mu or nu_tau) is that of a cylinder (Mobius strip).
Assuming that a change in topology dudring neutrino-neutrino transitions is
suppressed (e.g., one cannot continuously deform a donut into a sphere), while
neutrino-neutrino transitions without topology-change are (relatively)
enhanced, one may have an explanation for recent short-distance experimental
observations of (nearly) maximal nu_mu-nu_tau mixing at the Super Kamiokande.
To test this idea, I was able to use simple topological arguments to deduce a
matrix describing long-distance neutrino mixtures, which is identical to that
proposed by Georgi and Glashow on different grounds. Experimental confirmation
of this prediction would strongly support the new description of fundamental
fermions, which requires, among other things, that the nu_e and (nu_mu or
nu_tau) neutrinos start life as topoligically-distinct quantum objects.


title: Physicists Thriving with Paperless Publishing

abstract:
  The Stanford Linear Accelerator Center (SLAC) and Deutsches Elektronen
Synchrotron (DESY) libraries have been comprehensively cataloguing the High
Energy Particle Physics (HEP) literature online since 1974. The core database,
SPIRES-HEP, now indexes over 400,000 research articles, with almost 50% linked
to fulltext electronic versions (this site now has over 15 000 hits per day).
This database motivated the creation of the first site in the United States for
the World Wide Web at SLAC. With this database and the invention of the Los
Alamos E-print archives in 1991, the HEP community pioneered the trend to
"paperless publishing" and the trend to paperless access; in other words, the
"virtual library." We examine the impact this has had both on the way
scientists research and on paper-based publishing. The standard of work
archived at Los Alamos is very high. 70% of papers are eventually published in
journals and another 20% are in conference proceedings. As a service to
authors, the SPIRES-HEP collaboration has been ensuring that as much
information as possible is included with each bibliographic entry for a paper.
Such meta-data can include tables of the experimental data that researchers can
easily use to perform their own analyses as well as detailed descriptions of
the experiment, citation tracking, and links to full-text documents.


title: The shock-acoustic waves generated by earthquakes

abstract:
  We investigate the form and dynamics of shock-acoustic waves generated by
earthquakes. We use the method for detecting and locating the sources of
ionospheric impulsive disturbances, based on using data from a global network
of receivers of the GPS navigation system and requiring no a priori information
about the place and time of associated effects. The practical implementation of
the method is illustrated by a case study of earthquake effects in Turkey
(August 17, and November 12, 1999), in Southern Sumatera (June 4, 2000), and
off the coast of Central America (January 13, 2001). It was found that in all
instances the time period of the ionospheric response is 180-390 s, and the
amplitude exceeds by a factor of two as a minimum the standard deviation of
background fluctuations in total electron content in this range of periods
under quiet and moderate geomagnetic conditions. The elevation of the wave
vector varies through a range of 20-44 degree, and the phase velocity
(1100-1300 m/s) approaches the sound velocity at the heights of the ionospheric
F-region maximum. The calculated (by neglecting refraction corrections)
location of the source roughly corresponds to the earthquake epicenter. Our
data are consistent with the present views that shock-acoustic waves are caused
by a piston-like movement of the Earth surface in the zone of an earthquake
epicenter.


title: A realistic quasi-physical model of the 100 metre dash

abstract:
  A quasi-physical model (having both physical and mathematical roots) of
sprint performances is presented, accounting for the influence of drag
modification via wind and altitude variations. The race time corrections for
both men and women sprinters are discussed, and theoretical estimates for the
associated drag areas are presented. The corrections are consistent with
constant-wind estimates of previous authors, however those for variable wind
are more accentuated for this model. As a practical example, the nullified
World Record and 1988 Olympic 100 m race of Ben Johnson is studied, and
compared with the present World Record of 9.79 s.


title:
The use of GPS-arrays in detecting shock-acoustic waves generated during
  rocket launchings

abstract:
  This paper is concerned with the form and dynamics of shock-acoustic waves
(SAW) generated during rocket launchings. We have developed a method for
determining SAW parameters (including angular characteristics of the wave
vector, and the SAW phase velocity, as well as the direction towards the
source) using GPS-arrays whose elements can be chosen out of a large set of
GPS-stations of the global GPS network. The application of the method is
illustrated by a case study of ionospheric effects from launchings of launch
vehicles (LV) Proton and Space Shuttle from space-launch complexes Baikonur and
Kennedy Space Center (KSC) in 1998 and 1999 (a total of five launchings). The
study revealed that, in spite of a difference of LV characteristics, the
ionospheric response for all launchings had the character of an N - wave
corresponding to the form of a shock wave, regardless of the disturbance source
(rocket launchings, industrial explosions). The SAW period T is 270--360 s, and
the amplitude exceeds the standard deviation of TEC background fluctuations in
this range of periods under quiet and moderate geomagnetic conditions by
factors of 2 to 5 as a minimum. The angle of elevation of the SAW wave vector
varies from 30 degree to 60 degree, and the SAW phase velocity (900-1200 m/s)
approaches the sound velocity at heights of the ionospheric F-region maximum.


title:
New Design Study and Related Experimental Program for the LCLS RF
  Photoinjector

abstract:
  We report the results of a recent beam dynamics study, motivated by the need
to redesign the LCLS photoinjector, that lead to the discovery of a new
effective working point for a split RF photoinjector. We consider the emittance
compensation regime of a space charge beam: by increasing the solenoid
strength, the emittance evolution shows a double minimum behavior in the
drifting region. If the booster is located where the relative emittance maximum
and the envelope waist occur, the second emittance minimum can be shifted to
the booster exit and frozen at a very low level (0.3 mm-mrad for a 1 nC flat
top bunch), to the extent that the invariant envelope matching conditions are
satisfied. Standing Wave Structures or alternatively Traveling Wave Structures
embedded in a Long Solenoid are both candidates as booster linac. A careful
measurement of the emittance evolution as a function of position in the
drifting region is necessary to verify the computation and to determine
experimentally the proper position of the booster cavities. The new design
study and supporting experimental program under way at the SLAC Gun Test
Facility are discussed.


title: Fixed energy inversion of 5 eV e-Xe atom scattering

abstract:
  Fixed energy inverse scattering theory has been used to define central and
spin-orbit Schr\"odinger potentials for the scattering of 5 eV polarized
electrons from Xe atoms. The results are typical for a range of such data;
including energies above threshold when the potentials become complex. The
phase shifts obtained from an analysis of the measured differential cross
section and analyzing power has been used as input data. Both semi-classical
(WKB) and fully quantal inversion methods have been used to extract central and
spin-orbit interactions. The analysis shows that information additional to the
set of input phase shifts extracted from this (and similar) data may be needed
to ascertain physical potentials.


title: Method of laser-radiation guiding in plasma

abstract:
  The diffraction broadening of the intense laser radiation restricts its
efficient use in many applications. Proposed in the present work is a method
for laser radiation guiding in a density channel formed in plasma by a
relativistic electron beam. The conditions and parameters of the relativistic
beam ensuring the guiding by means of the proposed method have been examined.


title: Comment on Hydrogen-Antihydrogen collisions

abstract:
  A comment on a recent paper by P. Froelich et. al., Phys. Rev. Lett., 84,
4577 (2000) on hydrogen-antihydrogen collisions and on matter-antimatter
reactions in general. The center of mass of a stable HHbar system has prochiral
character. It is not necessary to look for large scale anti-matter domains at
distances Mpc away or at the cosmological horizon.


title:
Loading a vapor cell magneto-optic trap using light-induced atom
  desorption

abstract:
  Low intensity white light was used to increase the loading rate of $^{87}$Rb
atoms into a vapor cell magneto-optic trap by inducing non-thermal desorption
of Rb atoms from the stainless steel walls of the vapor cell. An increased Rb
partial pressure reached a new equilibrium value in less than 10 seconds after
switching on the broadband light source. After the source was turned off, the
partial pressure returned to its previous value in $1/e$ times as short as 10
seconds.


title:
Limit on Lorentz and CPT Violation of the Neutron Using a Two-Species
  Noble-Gas Maser

abstract:
  A search for sidereal variations in the frequency difference between
co-located 129-Xe and 3-He Zeeman masers sets the most stringent limit to date
on leading-order Lorentz and CPT violation involving the neutron, consistent
with no effect at the level of 10^{-31} GeV.

categories: physics.atom-ph hep-ex hep-ph nucl-ex physics.gen-ph


title: Clustering and Signalling of Cell Receptors

abstract:
  As a response to ligand binding, transmembrane cell receptors often enhance
their clustering, or oligomerization, during the signalling process. Here we
present a statistical mechanical model which combines the aspects of clustering
and signalling. In this model, receptors float on the surface, while for two
neighboring receptors, there is an interaction energy dependent on their
conformational states. On the other hand, ligand binding of a receptor shifts
the energy difference between the two conformational states. Due to thermal
fluctuation, the effects of clustering and signalling are statistical average
quantities. This model reduces to a floating Ising model with a random field.
We calculate the signalling in a grand canonical ensemble mean field approach,
using Hubbard-Stratonovich transformation and replica method. Monte Carlo
simulations are also performed. Essential biological features are obtained in
our model.


title: Quasi-continuous atom laser in the presence of gravity

abstract:
  We analyse the extraction of a coherent atomic beam from a trapped
Bose-Einstein condensate using a rf transition to a non-trapping state at T=0
K. Our quantum treatment fully takes gravity into account but neglects all
interactions in the free falling beam. We obtain an analytical expression of
the output rate and of the wave function of the extracted beam, i.e. the output
mode of the ``atom laser''. Our model reproduces satisfactorily experimental
data without any adjustable parameter.


title:
Design Studies for a High Current Bunching System for CLIC Test Facility
  (CTF3) Drive Beam

abstract:
  A bunching system is proposed for the initial stage of CTF3 which consists of
one (two) 3 GHz prebunchers and one 3 GHz travelling wave (TW) buncher with
variable phase velocities. The electron beam is emitted from a 140 KV DC gun.
Since the macropulse beam current (3.5 A) at the exit of the TW buncher is
rather high, inside the TW buncher one has to take the beam loading effect into
consideration. By using PARMELA, it is shown numerically that the bunching
system can provide the bunches whose properties satisfy the design requirement
of CTF3. The 0.8 m long TW buncher working at 2pi/3 mode has two phase
velocities, 0.75 and 1. The dimensions of the caities in the two phase velocity
regions are proposed considering the beam loading effect. The transient beam
loading effect and the multibunch transverse instabilities are studied
numerically, and it is concluded that higher order mode couplers should be
installed in the TW buncher with the loaded quality factor of the dipole mode
lower than 80.


title:
Temperature, Pressure & Solvent Dependence of Positronium Acceptor
  Reactions

abstract:
  Positronium (Ps) reaction rates (k) with weak Acceptors (Ac) leading to the
formation of Ps-Ac Complexes show several intriguing features: non-monotonic
temperature dependence of k (departing from the usual Arrhenius paradigm),
considerable variablity of k with respect to different solvents, and anomalies
in response to external pressure at ambient temperature (large changes of k in
some media and hardly any in others). We explain all these phenomena, through
the introduction of the novel concept of a critical surface tension, which
unifies observations in diverse non-polar solvents at different temperatures
and pressures.


title:
Condensates beyond mean field theory: quantum backreaction as
  decoherence

abstract:
  We propose an experiment to measure the slow log(N) convergence to mean-field
theory (MFT) around a dynamical instability. Using a density matrix formalism,
we derive equations of motion which go beyond MFT and provide accurate
predictions for the quantum break-time. The leading quantum corrections appear
as decoherence of the reduced single-particle quantum state.

categories: physics.atom-ph cond-mat physics.gen-ph quant-ph


title: Interaction between directional epistasis and average mutational effects

abstract:
  We investigate the relationship between the average fitness decay due to
single mutations and the strength of epistatic interactions in genetic
sequences. We observe that epistatic interactions between mutations are
correlated to the average fitness decay, both in RNA secondary structure
prediction as well as in digital organisms replicating in silico. This
correlation implies that during adaptation, epistasis and average mutational
effect cannot be optimized independently. In experiments with RNA sequences
evolving on a neutral network, the selective pressure to decrease the
mutational load then leads to a reduction of the amount of sequences with
strong antagonistic interactions between deleterious mutations in the
population.

categories: physics.bio-ph cond-mat.soft nlin.AO q-bio.PE