title: Mechanical analogies for the Lorentz gauge, particles and antiparticles

abstract:
  An exact analogy of electromagnetic fields and particles can be found in
mechanics of a turbulent ideal fluid with voids. The system is supposed to form
a fine dispersion of voids in the fluid. This microscopically discontinuous
medium is treated as a continuum. The turbulence is described in terms of the
Reynolds stresses. Perturbations of the homogeneous isotropic turbulence are
considered. For the high-energy low-pressure turbulence they are usually small.
This entails the linearization of the Reynolds equations. The latter appear to
be isomorphic to Maxwell's electromagnetic equations. The Lorentz gauge
expresses the slight effective compressibility of the medium. A particle can be
viewed as a cavity in the medium. A respective antiparticle is modeled with an
agglomerate of the medium's material. Microscopically, these correspond to some
nonlinear vortex formations in the "vortex sponge".


title: Short distance relativistic atom-atom forces

abstract:
  For the interactions between two atoms or between an ion and an electron the
connections between the Casimir-Polder-type potentials and the relativistic
potentials arising from the Breit-Pauli Hamiltonian are surveyed.


title: Compyter analysys of undulators with block-periodic structure

abstract:
  Methods to detect the spectral sensitivity of an object using undulator
radiation without monochromators or any other spectral devices are developed.
The spectral transmission function of the object is calculated from its
response to the spectrum-integral undulator radiation with the known spectral
distribution. This response is measured as a function of the electron energy.


title: Incoherent Energy Transfer within Light-harvesting Complexes

abstract:
  Rate equations are used to model spectroscopic observation of incoherent
energy transfer in light-harvesting antenna systems based upon known
structures. A two-parameter two-dimensional model is proposed. The transfer
rates obtained, by matching the fluorescent decay, are self-consistent within
our model.


title:
Time-dependent calculation of ionization in Potassium at mid-infrared
  wavelengths

abstract:
  We study the dynamics of the Potassium atom in the mid-infrared, high
intensity, short laser pulse regime. We ascertain numerical convergence by
comparing the results obtained by the direct expansion of the time-dependent
Schroedinger equation onto B-Splines, to those obtained by the eigenbasis
expansion method. We present ionization curves in the 12-, 13-, and 14-photon
ionization range for Potassium. The ionization curve of a scaled system, namely
Hydrogen starting from the 2s, is compared to the 12-photon results. In the
13-photon regime, a dynamic resonance is found and analyzed in some detail. The
results for all wavelengths and intensities, including Hydrogen, display a
clear plateau in the peak-heights of the low energy part of the Above Threshold
Ionization (ATI) spectrum, which scales with the ponderomotive energy Up, and
extends to 2.8 +- 0.5 Up.


title: How and Why the Universe Began

abstract:
  Before the universe there was nothing, absolute nothing. That is the starting
point because it is the only starting point that requires no cause, no
explanation nor justification of its existence.
  But, that starting point has two impediments to the universe, or anything,
coming into existence from it. First is the problem of change from nothing to
something without, at least initially, an infinite rate of change, which is
impossible. Second is the problem of change from nothing to something without
violating conservation, which must be maintained.
  Mathematical analysis develops the sole solution to both problems. That is
that the beginning had to be of a +/-[1 - cosine] form. That solution indicates
the fundamental nature of matter, energy and field.


title:
Acoustic band gap and coherence behavior in a periodic two-dimensional
  system

abstract:
  Here we show a complete band gap in acoustic propagation in water with
regularly placed air-cylinders. Also for the first time, we report that in the
gap, all cylinders oscillate in phase but exactly out of the phase of a wave
source located inside the cylinder array.


title:
Pump and Probe nonlinear processes: new modified sum rules from a simple
  oscillator model

abstract:
  The nonlinear oscillator model is useful to basically understand the most
important properties of nonlinear optical processes. It has been shown to give
the correct asymptotic behaviour and to provide the general feature of harmonic
generation to all orders, in particular dispersion relations and sum rules. We
investigate the properties of Pump and Probe processes using this model, and
study those cases where general theorems based on the holomorphic character of
the Kubo response function cannot be applied. We show that it is possible to
derive new sum rules and new Kramers-Kronig relations for the two lowest
moments of the real and imaginary part of the third order susceptibility and
that new specific contributions become relevant as the intensity of the probe
increases. Since the analitic properties of the susceptibility functions depend
only upon the time causality of the system we are confident that these results
are not model depemdent and therefore have a general validity, provided one
substitutes to the equilibrium values of the potential derivatives the density
matrix expectation values of the corresponding operators.


title:
Analytical Rebridging Monte Carlo: Application to cis/trans
  Isomerization in Proline-Containing, Cyclic Peptides

abstract:
  We present a new method, the analytical rebridging scheme, for Monte Carlo
simulation of proline-containing, cyclic peptides. The cis/trans isomerization
is accommodated by allowing for two states of the amide bond. We apply our
method to five peptides that have been previously characterized by NMR methods.
Our simulations achieve effective equilibration and agree well with
experimental data in all cases. We discuss the importance of effective
equilibration and the role of bond flexibility and solvent effects on the
predicted equilibrium properties.

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


title: Supersymmetry : A new organizing principle for the microworld?

abstract:
  A glorious achievement of twentieth century Physics is the identification of
the building blocks of nature. A related triumph a deep understanding of the
forces of interaction. In particular, it has been possible to understand the
four fundamental forces of nature in an elegant and unified mathematical
framework. The paradigm for this unification has been the principle of gauge
symmetry.
  A new approach to achieving further unification relies on Supersymmetry. This
is a symmetry which relates particles of integer spin with those of
half-integral spin and also dictates the allowed interactions among these
particles. However, no data exist pointing to the presence of this symmetry; it
may indeed be of no relevance to nature.
  In this paper the gauge principle and unification attempts are briefly
reviewed, and then Supersymmetry is introduced. The notion of "broken" symmetry
is discussed, which may explain why the symmetry is difficult to observe at
presently accessible energies. But a badly broken manifestation seems to remove
much of the original appeal and elegance of the theory. We here propose two
alternative views of the status of Supersymmetry from fundamental standpoint.
There is a good reason why it is indeed a fundamental symmetry, despite badly
broken. The alternative is that it is an organizing principle, somewhat like
valence. This makes it valuable as a signpost to new Physics.


title: Magnetism of Neutron Stars and Planets

abstract:
  It is shown in this paper that recent results that below the Fermi
temperature, Fermions obey anomalous semionic statistics, could explain such
apparently diverse phenomena as the magnetism of Pulsars and White Dwarfs on
the one hand and earth like planets, on the other.


title:
The Energetic Implications of Using Deforming Reference Descriptions to
  Simulate the Motion of Incompressible, Newtonian Fluids

abstract:
  In this work the issue of whether key energetic properties (nonlinear,
exponential-type dissipation in the abscence of forcing and long-term stability
under conditions of time dependent loading) are automatically inherited by
deforming reference descriptions is resolved. These properties are intrinsic to
real flows and the conventional Navier-Stokes equations. A completely general
reference description of an incompressible, Newtonian fluid, which reconciles
the differences between opposing schools of thought in the literature is
derived for the purposes of this investigation.
  The work subsequently focusses on establishing a class of time
discretisations which inherit these self-same energetic properties,
irrespective of the time increment employed. The findings of this analysis have
profound consequences for the use of certain classes of finite difference
schemes in the context of deforming references. It is significant that many
algorithms presently in use do not automatically inherit the fundamental
qualitative features of the dynamics. An `updated' approach as a means of
avoiding ever burgeoning deformation gradients and a still further simplified
implementation are further topics explored.


title:
Assessing the risk from the depleted uranium weapons used in Operation
  Allied Force

abstract:
  The conflict in Yugoslavia has been a source of great concern due to the
radiological and toxic hazard posed by the alleged presence of depleted uranium
in NATO weapons. In the present study some worst-case scenaria are assumed in
order to assess the risk for Yugoslavia and its neighboring countries . The
risk is proved to be negligible for the neighboring countries while for
Yugoslavia itself evidence is given that any increase in total long-term cancer
mortality will be so low that it will remain undetected. Local radioactive
hotspots such as DU weapons fragments and abandoned battle tanks, fortified or
contaminated with DU, constitute a post-war hazard which is not studied in this
article.


title:
Melting of the classical bilayer Wigner crystal: influence of the
  lattice symmetry

abstract:
  The melting transition of the five different lattices of a bilayer crystal is
studied using the Monte-Carlo technique. We found the surprising result that
the square lattice has a substantial larger melting temperature as compared to
the other lattice structures, which is a consequence of the specific topology
of the temperature induced defects. A new melting criterion is formulated which
we show to be universal for bilayers as well as for single layer crystals.


title: Quantum aspects of accelerator optics

abstract:
  Present understanding of accelerator optics is based mainly on classical
mechanics and electrodynamics. In recent years quantum theory of
charged-particle beam optics has been under development. In this paper the
newly developed formalism is outlined.


title: Quantum mechanical aspects of the halo puzzle

abstract:
  An interpretation of the ``halo puzzle'' in accelerators based on
quantum-like diffraction is given. Comparison between this approach and the
others based on classical mechanics equations is exhibited.


title:
Estimation of light transport parameters in biological media using
  coherent backscattering

abstract:
  The suitability of using the angular peak shape of the coherent backscattered
light for estimating the light transport parameters of biological media has
been investigated. Milk and methylene blue doped milk were used as tissue
phantoms for the measurements carried out with a He-Ne laser (632.8nm). Results
indicate that while the technique accurately estimates the transport length, it
can determine the absorption coefficient only when the absorption is moderately
high ($\alpha > 1 cm^{-1}$) for the long transport lengths typical of tissues.
Further, the possibility of determining the anisotropy factor by estimating the
single scattering contribution to the diffuse background is examined.


title: A molecular-dynamics algorithm for mixed hard-core/continuous potentials

abstract:
  We present a new molecular-dynamics algorithm for integrating the equations
of motion for a system of particles interacting with mixed continuous/impulsive
forces. This method, which we call Impulsive Verlet, is constructed using
operator splitting techniques similar to those that have been used successfully
to generate a variety molecular-dynamics integrators. In numerical experiments,
the Impulsive Verlet method is shown to be superior to previous methods with
respect to stability and energy conservation in long simulations.


title: Dynamics of lattice spins as a model of arrhythmia

abstract:
  We consider evolution of initial disturbances in spatially extended systems
with autonomous rhythmic activity, such as the heart. We consider the case when
the activity is stable with respect to very smooth (changing little across the
medium) disturbances and construct lattice models for description of
not-so-smooth disturbances, in particular, topological defects; these models
are modifications of the diffusive XY model. We find that when the activity on
each lattice site is very rigid in maintaining its form, the topological
defects - vortices or spirals - nucleate a transition to a disordered,
turbulent state.

categories: physics.bio-ph chao-dyn cond-mat.stat-mech nlin.CD q-bio.TO


title:
An axiomatic framework for classical particle mechanics without
  space-time

abstract:
  We present an axiomatic framework for non-relativistic classical particle
mechanics, inspired on Tati's ideas about a non-space-time description for
physics. The main advantage of our picture is that it allows us to describe
causality without any reference to elapsed time intervals.


title:
Finite Element Simulation of the Motion of a Rigid Body in a Fluid with
  Free Surface

abstract:
  In this work a finite element simulation of the motion of a rigid body in a
fluid, with free surface, is described. A completely general referential
description (of which both Lagrangian and Eulerian descriptions are special
cases) of an incompressible, Newtonian fluid is used. Such a description
enables a distorting finite element mesh to be used for the deforming fluid
domain.
  A new scheme for the linearised approximation of the convective term is
proposed and the improved, second order accuracy of this scheme is proved. A
second theorem, which provides a guideline for the artificial adjustment of the
Reynolds number when applying a continuation technique, is also proved. The
most effective means of eliminating pressure as a variable and enforcing
incompressibility are reviewed. A somewhat novel method to generate finite
element meshes automatically about included rigid bodies, and which involves
finite element mappings, is described.
  The approach taken when approximating the free surface, is that it may be
treated as a material entity, that is, the material derivative of the free
surface is assumed zero. Euler's equations and conservation of linear momentum
are used to determine the motion of the rigid body. A predictor-corrector
method is used to solve the combined sub-problems. The resulting model is
tested in the context of a driven cavity flow, a driven cavity flow with
various, included rigid bodies, a die-swell problem, and a Stokes second order
wave.


title: Beam Test of Gamma-ray Large Area Space Telescope Components

abstract:
  A beam test of GLAST (Gamma-ray Large Area Space Telescope) components was
performed at the Stanford Linear Accelerator Center in October, 1997. These
beam test components were simple versions of the planned flight hardware.
Results on the performance of the tracker, calorimeter, and anti-coincidence
charged particle veto are presented.


title:
The Correlation Between Gravitation and Electromagnetism, Inertia and
  Unification

abstract:
  We show that gravitational mass and inertial mass are correlated by an
adimentional factor, which in specific electromagnetic conditions, can be
reduced, nullified, negated, and increased. Some theoretical consequences of
the mentioned correlation are: the generalization of Newton=92s second law for
the motion (New law for Inertia); the deduction of the differential equation
for entropy (second law of Thermodynamics); unification of gravitational and
electromagnetic interactions .


title: Anomalous Fermions II

abstract:
  Recently the anomalous behaviour of Fermions below the Fermi temperature was
analysed in detail from different viewpoints. In the present communication we
obtain a justification for this anomalous semionic behaviour and also obtain
the Cooper pair type scenario of superconductivity from an alternative
standpoint. Finally an earlier result in one dimension that an assembly of
Fermions at any temperature behaves as if it is below the Fermi temperature is
extended to the two dimensional case.


title: K-Theory and Gauge Solitons

abstract:
  The spectrum of D-brane charges in the Type IIB string theory compactified on
$AdS_{p+2}\times S^{8-p}$ is computed using the K-theory approach. The result
differs from the corresponding result presented in the digest of Olsen and
Szabo.


title:
A Consistent Computational Time-Dependent Electron-Exchange Theory With
  Non-Redundant Time Evolution

abstract:
  In the present work, a new time-dependent exchange theory is presented
wherein the symmetry constraints, on a multi-electron wavefunction, are
properly accounted for. In so doing, the equations of motion, incorporating the
required symmetry, are derived and a solution algorithm employing an implicit
split-operator procedure is described. A technique (using an orthonormalization
transformation and a unitary rotation), for explicitly enforcing the required
constraints, which render the computations tractible and provide for
non-redundant time evolution, is also presented. This amounts to the
calculation of the appropriate numerically determined guage. The invariance of
the derived orbital equations of motion with respect to the transformations is
explicitly demonstrated.


title:
Superconductivity The Structure Scale of the Universe (Twenty Fourth
  Edition)

abstract:
  A numerical and dimensional correlation supported by reported literature
experimental evidence (Homes, Harshmann along with Voyager, EGRET, FERMI, WMAP,
Planck and other space platforms) is presented which indicates that
superconductivity is congruent with Charge Conjugation, Parity Change and
TimeReversal (CPT) theorem and scalable with Friedmann Lemaire Robertson Walker
(FLRW) cosmology within the concept of Schwinger pair production, Maxwell's
permittivity-permeability and the de Broglie hypothesis. This momentum and
energy conserving (elastic) CPT resonant structural lattice reverses phase and
group velocities at the nuclear dimension as dictated by the speed of light and
is scalable over 15 ours of magnitude from nuclear to universe dimensions, from
the universe Big Bang event to present and is consistent with nuclear (quark)
weak and strong forces, electromagnetic and gravitational forces being mediated
by a particle of constant mass (110.123 x electron mass or 56.3 MeV/c2) related
to the Higgs mass. This isotropic homogeneous CPT structure filling the space
vacuum presently defines an extremely cold dark energy condition (<<CMBR) that
dictates an equally extremely cold baryonic dark matter. The model predicts a
deceleration value consistent with flat galactic rotation curves and with
observed Pioneer 10 and 11 deep space translation and rotational deceleration
and is generally consistent with the notion that: An object moving through
momentum space will decelerate. This deceleration concept allows Type 1A
supernovae universe expansion data to be interpreted as if the local universe
is slowing down with respect to the rest. The predicted 33.8 microHz universe
oscillations are observed by The LISA Pathfinder and stellar core gravity
waves. The entire concept focuses towards engineering a critical optical volume
energy (COVE) as a possible energy source.


title: Limit Cycle Oscillations in Pacemaker Cells

abstract:
  In recent decades, several mathematical models describing the pacemaker
activity of the rabbit sinoatrial node have been developed. We demonstrate that
it is not possible to establish the existence, uniqueness, and stability of a
limit cycle oscillation in those models. Instead we observe an infinite number
of limit cycles. We then display numerical results from a new model, with a
limit cycle that can be reached from many different initial conditions.


title: Potential of an ionic impurityin a large $^4$He cluster

abstract:
  This paper presents an analysis of the motion of an impurity ion in a
nanometer scale $^4$He cluster. Due to induction forces, ions are strongly
localized near the center of the cluster, with a root mean squared thermal
displacements of only a few \AA. The trapping potential is found to be nearly
harmonic, with a frequency of 2.3(1.0) GHz for a positive (negative) ion in a
He cluster of radius 5 nm. The anharmonicity is small and positive (energy
increases slightly faster than linear with quantum number). It is suggested
that by using frequency sweep microwave radiation, it should be possible to
drive the ion center of mass motion up to high quantum numbers, allowing the
study of the critical velocity as a function of cluster size.


title: Potential of a neutral impurity in a large $^4$He clusters

abstract:
  This paper presents an analysis of the motion of an neutral impurity species
in a nanometer scale $^4$He cluster, extending a previous study of the dynamics
of an ionic impurity. It is shown that for realistic neutral impurity-He
potentials, such as those of SF$_6$ and OCS, the impurity is kept well away of
the the surface of the cluster by long range induction and dispersion
interactions with He, but that a large number of `particle in a box' center of
mass states are thermally populated. It is explicitly demonstrated how to
calculate the spectrum that arises from the coupling of the impurity rotation
and the center of mass motion, and it is found that this is a potentially
significant source of inhomogeneous broadening in vibration-rotation spectra of
anisotropic impurities. Another source of inhomogeneous broadening is the
hydrodynamic coupling of the rotation of the impurity with the center of mass
velocity. A quantum hamiltonian to describe this effect is derived from the
classical hydrodynamic kinetic energy of an ellipsoid. Simple analytic
expressions are derived for the resulting spectral line shape for an impurity
in bulk He, and the relevant matrix elements derived to allow fully quantum
calculations of the coupling of the center of mass motion and rotation for an
impurity confined in a spherical He cluster. Lastly, the hydrodynamic
contribution to the impurity effective moment of inertia is evaluated and found
to produce only a minor fractional increase.


title:
Characteristics of synchrotron radiation of longitudinally polarized
  spinning particle in the pseudoclassical theory

abstract:
  Spin dependencies of the intensity and polarization of the synchrotron
radiation of the longitudinally polarized particle performing uniform circular
motion in the magnetic field are investigated.


title:
Low-dimensional dynamics embedded in a plane Poiseuille flow turbulence
  : Traveling-wave solution is a saddle point ?

abstract:
  The instability of a streak and its nonlinear evolution are investigated by
direct numerical simulation (DNS) for plane Poiseuille flow at Re=3000. It is
suggested that there exists a traveling-wave solution (TWS). The TWS is
localized around one of the two walls and notably resemble to the coherent
structures observed in experiments and DNS so far. The phase space structure
around this TWS is similar to a saddle point. Since the stable manifold of this
TWS is extended close to the quasi two dimensional (Q2D) energy axis, the
approaching process toward the TWS along the stable manifold is approximately
described as the instability of the streak (Q2D flow) and the succeeding
nonlinear evolution. Bursting corresponds to the escape from the TWS along the
unstable manifold. These manifolds constitute part of basin boundary of the
turbulent state.


title: Conditions for the Formation of Axisymmetric Biconcave Vesicles

abstract:
  In this article, the formation of biconcave vesicle according to the
minimization bending energy (Helfrich's model) is studied. We present that in
order to have biconcave shape vesicle, there are necessary conditions on the
parameters of the energy functional and there are implications on the geometric
quantities of the vesicle. Furthermore, we also give a clear sufficient
condition on the parameters to have the formation of biconcave shape vesicle.


title: A Brief Note on Jupiter's Magnetism

abstract:
  A recent model which gives the contribution of the earth's solid core to geo
magnetism is seen to explain Jupiter's magnetism also.


title:
On spin-rotation contribution to nuclear spin conversion in
  C_{3v}-symmetry molecules. Application to CH_3F

abstract:
  The symmetrized contribution of E-type spin-rotation interaction to
conversion between spin modifications of E- and A_1-types in molecules with
C_{3v}-symmetry is considered. Using the high-J descending of collisional
broadening for accidental rotational resonances between these spin
modifications, it was possible to co-ordinate the theoretical description of
the conversion with (updated) experimental data for two carbon-substituted
isotopes of fluoromethane. As a result, both E-type spin-rotation constants are
obtained. They are roughly one and a half times more than the corresponding
constants for (deutero)methane.


title:
Parametric Resonance in the Drift Motion of an Ionic Bubble in near
  critical Ar Gas

abstract:
  The drift mobility of the negative oxygen ion in dense Argon gas near the
liquid-vapor critical point has been measured as a function of the density.
Near the critical temperature the zero-field density-normalized ion mobility
shows a deep minimum at a density smaller than the critical one. This
phenomenon was previously intepreted as the result of the formation of a
correlated cluster of Argon atoms around the ion because of the strong
electrostriction exerted by the ion on the highly polarizable and compressible
gas. We now suggest that a possible alternative explanation is related to the
onset of a parametric resonance of a bubble surrounding the ion. At resonance a
large amount of energy is dissipated by sound waves in addition to viscous
dissipation processes, resulting in the large mobility drop observed.


title: Intrinsic Kinematics

abstract:
  We show how some geometric elements of the path of a particle moving in a
plane -- the osculating circle and its radius of curvature -- can be used to
construct the parabolic trajectory of projectiles in motion under gravity.


title: Difficult Problems Having Easy Solutions

abstract:
  We discuss how a class of difficult kinematic problems can play an important
role in an introductory course in stimulating students' reasoning on more
complex physical situations. The problems presented here have an elementary
analysis once certain symmetry features of the motion are revealed. We also
explore some unexpected directions these problems lead us.


title:
The evolution and revival structure of angular momentum quantum wave
  packets (Tutorial)

abstract:
  In this paper a coherent superposition of angular momentum states created by
absorption of polarized light by molecules is analyzed. Attention is paid to
the time evolution of wave packets representing spatial orientation of
internuclear axis of diatomic molecule. Two examples are considered in detail.
Molecules absorbing light in a permanent magnetic field experiencing Zeeman
effect and molecules absorbing light in a permanent electric field experiencing
quadratic Stark effect. In a magnetic field we have a wave packet that evolves
in time exactly as classical dipole oscillator in a permanent magnetic field.
In the second case we have the wave packet that goes through periodical changes
of a shape of the packet and revivals of initial shape. This is a pure quantum
behavior. Classical motion of angular momentum in an electric field in case of
quadratic Stark effect is known to be aperiodic. Obtained solutions for wave
packet evolution are briefly compared with Rydberg state coherent wave packets
and harmonic oscillator wave packets.


title: Calculation of ionization within the close-coupling formalism

abstract:
  An adaptation of the convergent close-coupling method (CCC) to calculation of
differential ionization cross sections is analyzed in the context of the
Temkin-Poet model. The asymptotic scattering wave functions and the unitarity
relation are given for the model. It is concluded the use of "distinguishable"
electrons as proposed in the CCC model is not essential in the close-coupling
formulation of ionization.


title: Test your surrogate data before you test for nonlinearity

abstract:
  The schemes for the generation of surrogate data in order to test the null
hypothesis of linear stochastic process undergoing nonlinear static transform
are investigated as to their consistency in representing the null hypothesis.
In particular, we pinpoint some important caveats of the prominent algorithm of
amplitude adjusted Fourier transform surrogates (AAFT) and compare it to the
iterated AAFT (IAAFT), which is more consistent in representing the null
hypothesis. It turns out that in many applications with real data the
inferences of nonlinearity after marginal rejection of the null hypothesis were
premature and have to be re-investigated taken into account the inaccuracies in
the AAFT algorithm, mainly concerning the mismatching of the linear
correlations. In order to deal with such inaccuracies we propose the use of
linear together with nonlinear polynomials as discriminating statistics. The
application of this setup to some well-known real data sets cautions against
the use of the AAFT algorithm.


title:
Single and Double Resonance Microwave Spectroscopy in Superfluid $^4$He
  Clusters

abstract:
  Purely rotational transitions of a molecule, such as HCCCN, embedded in large
$^4$He clusters have been detected for the first time. The saturation behavior
shows that, in contrast to previous expectations, the microwave line profiles
are dominated by inhomogeneous broadening mechanisms. Spectral holes and peaks
produced by microwave-microwave double resonance have widths comparable to
those of single resonance lines, indicating that relaxation occurs among
quantum states of the inhomogeneous distribution of each rotational level, at a
rate approximately 10 times faster than rotationally inelastic relaxation.


title:
Progetto per la costituzione del centro di divulgazione della cultura
  scientifica a Sesto Fiorentino

abstract:
  Two Italian non-profit organizations (Set and Galea) are working together to
realize a center (Cdcs) supported by the town administration of Sesto
Fiorentino (a little town not far from Florence, Italy), for the divulgation of
the scientific culture in the schools and among people. This is their project:
the key idea is to let the non-profit organizations intervent in the public
school system by creating cooperative structures in which young scientists can
work.


title: Short time dynamics with initial correlations

abstract:
  The short-time dynamics of correlated systems is strongly influenced by
initial correlations giving rise to an additional collision integral in the
non-Markovian kinetic equation. Exact cancellation of the two integrals is
found if the initial state is thermal equilibrium which is an important
consistency criterion. Analytical results are given for the time evolution of
the correlation energy which are confirmed by comparisons with molecular
dynamics simulations (MD).

categories: physics.plasm-ph cond-mat.stat-mech nucl-th physics.gen-ph


title: Fermi Temperature Magnetic Effects

abstract:
  Recent results than an assembly of Fermions below the Fermi temperature would
exhibit anamolous semionic behaviour are examined in the context of assoociated
magnetic fields.


title: Towards the Unification of Fundamental Interactions

abstract:
  Recent observations of distant supernovae show that the universe, contrary to
popular belief, is expanding for ever. Similarly, recent experiments at the
Superkamiokande facility demonstrate that the Neutrino has a non vanishing
mass. Both these discoveries necessitate, at the very least, a re-examination
of conventional theories-the Big Bang Theory and the Standard Model. On the
other hand, neither has quantum gravity yielded the desired results, nor can
String Theory be taken as the last word. We briefly examine this scenario, and
in this light consider the recent description of Fermions in terms of the
Kerr-Newman metric and the related model of Fluctuational Cosmology. All this
is not only consistent with known physics including the latest results alluded
to, but also explains hitherto inexplicable empirical facts like the handedness
of the Neutrino or the large number relations of Cosmology and so on. It is
shown that this scheme leads to a unified description of the fundamental
interactions. At the same time, pleasingly, we recover the usual quark picture
at the Compton wavelength scale and the Big Bang scenario at the Planck scale.


title:
Measurability of side chain rotational isomer populations: NMR and
  molecular mechanics of cobalt glycyl-leucine dipeptide model system

abstract:
  The cobalt glycyl-leucine dipeptide is a model system for studying the
effects of Karplus equation calibration, molecular mechanics accuracy, backbone
conformation, and thermal motions on the measurability of side chain rotational
isomer populations. We analyze measurements of 8 vicinal coupling constants
about the alpha to beta-carbon and beta to gamma-carbon bonds of the leucine
side chain and of 10 NOESY cross relaxation rates across these bonds. Molecular
mechanics and peptide and protein crystallographic databases are an essential
part of this analysis because they independently suggest that the trans
gauche-plus and gauche-minus trans rotational isomers of the leucine side chain
predominate. They also both suggest that puckering of the cobalt dipeptide ring
system reduces the gauche-plus gauche-plus rotational isomer population to less
than about 10%. At the present +/- 1 Hz calibration accuracy of Karplus
equations for vicinal coupling constants, the predominant trans gauche-plus and
gauche-minus trans rotational isomer populations can be measured with about 5%
accuracy, but the population of the gauche-plus gauche-plus rotational isomer
is probably very near or just below the limit of measurability. These estimates
also depend upon qualitative assessments of the accuracy of the molecular
mechanics energy wells. We introduce gel graphics that are ideally suited to
presenting qualitative error and measurability estimates.


title: Verification of a localization criterion for several disordered media

abstract:
  We analytically compute a localization criterion in double scattering
approximation for a set of dielectric spheres or perfectly conducting disks
uniformly distributed in a spatial volume which can be either spherical or
layered. For every disordered medium, we numerically investigate a localization
criterion, and examine the influence of the system parameters on the wavelength
localization domains.


title: Interferometry of hyper-Rayleigh scattering by inhomogeneous thin films

abstract:
  The use of specific symmetry properties of the optical second-harmonic
generation (the s,s-exclusion rule) has allowed us to observe high-contrast
hyper-Rayleigh interference patterns in a completely diffuse light - an effect
having no analog in case of linear (Rayleigh) scattering.


title:
On the gravitational field of a mass point according to Einstein's
  theory

abstract:
  Translation by S. Antoci and A. Loinger of the fundamental memoir, that
contains the ORIGINAL form of the solution of Schwarzschild's problem. The
solution is regular in the whole space-time, with the only exception of the
origin of the spatial co-ordinates; consequently, it leaves no room for the
science fiction of the black holes. (In the centuries of the decline of the
Roman Empire people said: ``Graecum est, non legitur''...).


title: Emission Optics of the Steigerwald Type Electron Gun

abstract:
  The emission optics of a Steigerwald type electron gun is re-examined. The
virtual and real points of divergence, divergence angles and beam-widths of the
electron beams at different telefocusing strength are measured in detail for
first time . Two different Wehnelt cylinders are used to establish a
contrasting viewpoint. The original `focusing' curves measured by Braucks are
reconstructed and will be explained only through a `new' interpretation which
is different from the conventional views. While the image of the emitting
surface in front of the filament is indeed telefocused beyond the anode, the
envelope of the beam does not `focus' as expected. A new model for the emission
mechanism is established based on our results.


title:
Investigation of a 90 Degree Spherical Deflecting Analyzer Operated in
  an Asymmetrically Charged Configuration

abstract:
  The electron optics of a 90 degree spherical deflecting analyzer (SDA-90) is
investigated with an imaging matrix formalism. As a preanalyzer in the
UTA-neutrino experiment, high transmission and reasonable energy resolution are
the choices of optimization. The magnification of the source through the
analyzer plays the key role in determining the energy resolution. The imaging
matrix approach provides graphical information to facilitate such an
evaluation. We can demonstrate that in case where the analyzer is
asymmetrically charged, the rotation of the image helps increase both
transmission probability and resolution. A telefocus electron gun is used to
check the numerical result, and to investigate the transverse focusing
behavior.


title: Study of Multiple-Beam RFQ

abstract:
  There are applications, which require MeV-range multiple-beams consisting of
a large number of identical highly packed beamlets. The multiple-beam RFQ
(MB-RFQ) arranged as a matrix array of longitudinal rod-electrodes is
appropriate candidate. A configuration of MB-RFQ resonator should ensure
identical quadrupole fields in every accelerating channel. The MB-RFQ
resonators based on TEM transmission lines are studied. The resonators are
designed by a periodical multiplication of a 4-rod unit cell in transverse
direction. To understand fields of resonator the normal mode technique is
applied. Novel configurations of MB-RFQ resonators based on these normal modes
are generated. The RF properties of resonators are verified with computer
simulations done with MAFIA code. Beam dynamics study for the initial 400-keV
MB-RFQ has been performed using PARMTEQ code. The MB-RFQ parameters and the
results of beam dynamics simulations are presented. The calculated beam
transmission is 33% at injection of 50-keV, 20mA deuteron beam.


title: Quantum-like approaches to the beam halo problem

abstract:
  An interpretation of the ``halo problem'' in accelerators based on
quantum-like diffraction is given. Comparison between this approach and the
others based on classical mechanics equations is discussed.


title: The recursive adaptive quadrature in MS Fortran-77

abstract:
  It is shown that MS Fortran-77 compilers allow to construct recursive
subroutines. The recursive one-dimensional adaptive quadrature subroutine is
considered in particular. Despite its extremely short body (only eleven
executable statements) the subroutine proved to be very effective and
competitive. It was tested on various rather complex integrands. The
possibility of function calls number minimization by choosing the optimal
number of Gaussian abscissas is considered. The proposed recursive procedure
can be effectively applied for creating more sophisticated quadrature codes
(one- or multi-dimensional) and easily incorporated into existing programs.


title:
Electromagnetic radiation of the travelling spin wave propagating in an
  antiferromagnetic plate. Exact solution

abstract:
  The exact solution of radiation problem of a spin wave travelling in an
antiferromagnetic (AFM) plate was found. The spin wave with in-plane
oscillations of antiferromagnetism vector was considered. In this case the
magnetization vector is oscillating being perpendicular to the AFM plate and
depends on time and plane coordinates as travelling wave does. This model
allows to obtain exact analytical expression for Hertzian vector and,
consequently, the retarded potentials and field strengths as well. It is shown
that expressions obtained describe Cherenkov radiation caused by the travelling
wave. The radiated electromagnetic wave is the TEM type if a phase velocity
exceeds the speed of light. Otherwise electric and magnetic field values
exponentially decrease in the direction normal to the plate. The energy losses
were evaluated also.


title: Mechanical analogies for gravitation

abstract:
  A quasielastic model of gravitation is developed. Gravitational field is
modeled by the flow of the transient point dilatation, which is supposed to be
continually emitted by a discontinuity of the turbulent fluid. Gravitational
attraction arises from the contact interaction of the dilatation centers.
Gravitational wave is viewed microscopically as the axisymmetric wave
propagating at a high speed along a vortex tube.


title: Ionization of a Model Atom: Exact Results and Connection with Experiment

abstract:
  We prove that a model atom having one bound state will be fully ionized by a
time periodic potential of arbitrary strength $r$ and frequency $\omega$. The
survival probability is for small $r$ given by $e^{-\Gamma t}$ for times of
order $\Gamma^{-1} \sim r^{-2n}$, where $n$ is the number of ``photons''
required for ionization, with enhanced stability at resonances. For late times
the decay is like $t^{-3}$. Results are for a 1d system with a delta function
potential of strength $-g(1 + \eta (t))$ but comparison with experiments on the
microwave ionization of excited hydrogen atoms and with recent analytical work
indicate that many features are universal.


title:
Dynamic Stability of The Time-averaged Orbiting Potential Trap: Exact
  Classical Analysis

abstract:
  We calculate exactly the modes of motion of the Time-averaged Orbiting
Potential (TOP) trap with its four degrees of freedom, namely the three
translations and the spin, taken into account. We find that, when gravity is
neglected, there are two parameters in the problem namely, the angular velocity
of the rotating field and its strength. We present the stability diagram in
these parameters. We find the mode frequencies calculated from the
time-averaged potential model used by the inventors of the TOP is an excellent
approximation to our exact results. However, for other parameters, this may not
be the case.


title: General Relativity and Contrary Predictions

abstract:
  Using the accepted methods to extract natural system behavior from the
Einstein-Hilbert gravitational field tensor equation, a new coordinate
transformation is analyzed. It is demonstrated that these extraction methods
yield specific contradictions. Two such contradictions are that for an
electrically neutral (non-rotating) Schwarzschild configuration there is an
infinite redshift surface that is not an event horizon and, for the same
Schwarzschild configuration, no dustlike particle external to this
configuration will, with respect to proper time, ever gravitationally collapse
radially to the surface of the configuration.


title: Quiet Violin

abstract: This is a letter to editor, about a previously published paper and comments.


title: Heron Variables in 3-body Coulomb Problem

abstract:
  The use of coordinate variables with independent physical boundaries -- Heron
variables -- is proposed for the 3-body problem. The ansatz is given for
variational trial wave functions without local energy infinities at the Coulomb
singularities


title:
Large Contributions of Negative Energy States to Forbidden
  Magnetic-Dipole Transition Amplitudes in Alkali-Metal Atoms

abstract:
  The influence of negative-energy states (NES) on forbidden magnetic-dipole
$ns_{1/2}-(n+1)s_{1/2}$ transitions in alkali-metal atoms is investigated. We
find that the NES contributions are significant in almost all cases and for
rubidium reduce the transition rate by a factor of 8. We tabulate
magnetic-dipole (M_1) transition amplitudes for the alkalis. Our M_1 value for
cesium, where accurate measurements are available, differs from experiment by
16%. We briefly discuss the feasibility of an experimental test of NES effects.


title: Integration of Complete System of Dynamic Equations for Ideal Fluid

abstract:
  The Eulerian system of dynamic equations for the ideal fluid is closed but
incomplete. The complete system of dynamic equations arises after appending Lin
constraints which describe motion of fluid particles in a given velocity field.
The complete system of dynamic equations for the ideal fluid can be integrated.
Description in terms of hydrodynamic potentials (DTHP) arises as a result of
this integration. The integrated system contains indefinite functions of three
arguments, which can be expressed via initial and boundary conditions. The
remaining initial and boundary conditions for the integrated system can be made
universal (i.e. the same for all fluid flows), and the resulting system of
equations contains full information about the fluid flow including initial and
boundary conditions for the fluid flow. Some hydrodynamic potentials appear to
be frozen into the fluid, and the Kelvin's theorem on the velocity circulation
can be formulated in a contour-free form. Description in terms of the wave
function (DTWF) appears to be a kind of DTHP. Calculation of slightly
rotational flows can be carried out on the basis of DTHP, or DTWF. Such a
description of a rotational flow appears to be effective.


title:
Enskog-Landau kinetic equation for multicomponent mixture. Analytical
  calculation of transport coefficients

abstract:
  The Enskog-Landau kinetic equation is considered to describe non-equilibrium
processes of a mixture of charged hard spheres. This equation has been obtained
in our previous papers by means of the non-equilibrium statistical operator
method. The normal solution of this kinetic equation found in the first
approximation using the standard Chapman-Enskog method is given. On the basis
of the found solution the flows and transport coefficients have been
calculated. All transport coefficients for multicomponent mixture of spherical
Coulomb particles are presented analytically for the first time. Numerical
calculations of thermal conductivity and thermal diffusion coefficient are
performed for some specific mixtures of noble gases of high density. We compare
the calculations with those ones for point-like neutral and charged particles.


title:
Excitation of nonlinear one-dimensional wake waves in underdense and
  overdense magnetized plasma by a relativistic electron bunch

abstract:
  The excitation of wake waves by a relativistic homogeneous electron bunch
passing through cold magnetized plasma at equilibrium is studied for arbitrary
values of the ratio of bunch density to plasma density. The analysis is based
on the assumption that the magnetic field is sufficiently strong ($\omega_B\gg
\omega_p$, where $\omega_p$ and $\omega_B$ are the electron plasma and
cyclotron frequences respectively). The periodic and nonperiodic solutions for
the momentum of plasma electrons inside and outside the bunch are analyzed. It
was shown that the presence of strong external magnetic field may increase the
amplitude of wake waves and the maximum transformer ratio, the latter being
reached at densities of bunch lower than that in the absence of magnetic field.
The optimum conditions for obtaining the maximum values of the wake field
amplitude and of the transformer ratio are found.


title: High precision atom interferometry in a microgravity environment

abstract:
  We propose a set of experiments in which Ramsey-fringe techniques are
tailored to probe transitions originating and terminating on the same ground
state level. When pulses of resonant radiation, separated by a time delay $% T,
$ interact with atoms, it is possible to produce Ramsey fringes having widths
of order 1/T. If each pulse contains two counterpropagating travelling wave
modes, the atomic wave function is split into two or more components having
different center-of-mass momenta. Matter-wave interference of these components
leads to atomic gratings, which have been observed in both spatially separated
fields and time separated fields. Time-dependent signals can be transformed
into frequency dependent signals, leading to ground state Ramsey fringes
(GSRF). The signals can be used to probe many problems of fundamental
importance: a precise measurement of the earth gravitational acceleration $g$
and residual gravity in a microgravity environment with an accuracy $6
10^{-9}g;$ the rotation rate measurement with an accuracy of 6 10^{-3} deg/h;
the recoil frequency measurement.
  Since only transitions originating and terminating on the same ground state
are involved, frequency measurements can be carried out using lasers
phase-locked by quartz oscillators having relatively low frequency. Our
technique may allow one to increase the precision by a factor of 100 (the rf-
to quartz oscillator frequencies ratio) over previous experiments based on
Raman-Ramsey fringes or reduce on the same factor requirements for frequency
stabilization.


title: A New Bilirubin Concentration Detection Method by Light Reflection

abstract:
  A new and simple method of blood bilirubin detection through light reflection
from skin is developed. The basic improvement over the existing methods is in
the design of the light emitter and detector geometry which facilitates a
two-stream plane parallel homogenous medium solution to the emitting-scatterig
radiative transfer equation. The forward peak in the scattering phase function
that is characteristic of water droplets and water filled media is accounted
for through a proper method named delta-Eddington approximation.


title: The Past Earth's Rotation

abstract:
  We have proposed a model to obtain the length of the day and month at any
geologic time. The day is found to increase by 0.002 sec/century since the
seventeenth century. The lengthening of the day is attributed entirely to the
increasing gravitational constant ($G$) with time that manifested its self in
tidal forces. The data obtained are consistent with those found from
Palaeontology. The length of the day 4500 million years ago was 6 hours and the
synodic month was 56.26 present epoch days.


title: Classical Tunneling of Sommerfeld Sphere in Classical Electrodynamics

abstract:
  One-dimensional motion of Sommerfeld sphere in the case of potential barrier
is numerically investigated. The effect of classical tunneling is found out -
Sommerfeld sphere overcomes the barrier and finds itself in the forbidden, from
classical point of view, area.


title: Quantum Three-Body Problem

abstract:
  An improved hyperspherical harmonic method for the quantum three-body problem
is presented to separate three rotational degrees of freedom completely from
the internal ones. In this method, the Schr\"{o}dinger equation of three-body
problem is reduced to a system of linear algebraic equations in terms of the
orthogonal bases of functions. As an important example in quantum mechanics,
the energies and the eigenfunctions of some states of the helium atom and the
helium-like ions are calculated.


title: Geometry and symmetries of multi-particle systems

abstract:
  The quantum dynamical evolution of atomic and molecular aggregates, from
their compact to their fragmented states, is parametrized by a single
collective radial parameter. Treating all the remaining particle coordinates in
d dimensions democratically, as a set of angles orthogonal to this collective
radius or by equivalent variables, bypasses all independent-particle
approximations. The invariance of the total kinetic energy under arbitrary
d-dimensional transformations which preserve the radial parameter gives rise to
novel quantum numbers and ladder operators interconnecting its eigenstates at
each value of the radial parameter.
  We develop the systematics and technology of this approach, introducing the
relevant mathematics tutorially, by analogy to the familiar theory of angular
momentum in three dimensions. The angular basis functions so obtained are
treated in a manifestly coordinate-free manner, thus serving as a flexible
generalized basis for carrying out detailed studies of wavefunction evolution
in multi-particle systems.


title:
Alternative sets of hyperspherical harmonics: Satisfying cusp conditions
  through frame transformations

abstract:
  By extending the concept of Euler-angle rotations to more than three
dimensions, we develop the systematics under rotations in higher-dimensional
space for a novel set of hyperspherical harmonics. Applying this formalism, we
determine all pairwise Coulomb interactions in a few-body system without
recourse to multipole expansions. Our approach combines the advantages of
relative coordinates with those of the hyperspherical description. In the
present method, each Coulomb matrix element reduces to the ``1/r'' form
familiar from the two-body problem. Consequently, our calculation accounts for
all the cusps in the wave function whenever an interparticle separation
vanishes. Unlike a truncated multipole expansion, the calculation presented
here is exact. Following the systematic development of the procedure for an
arbitrary number of particles, we demonstrate it explicitly with the simplest
nontrivial example, the three-body system.


title: Theoretical study of the absorption spectra of the lithium dimer

abstract:
  For the lithium dimer we calculate cross sections for absorption of radiation
from the vibrational-rotational levels of the ground X [singlet Sigma g +]
electronic state to the vibrational levels and continua of the excited A
[singlet Sigma u +] and B [singlet Pi u] electronic states. Theoretical and
experimental data are used to characterize the molecular properties taking
advantage of knowledge recently obtained from photoassociation spectroscopy and
ultra-cold atom collision studies. The quantum-mechanical calculations are
carried out for temperatures in the range from 1000 to 2000 K and are compared
with previous calculations and measurements.


title: Experimental study of Taylor's hypothesis in a turbulent soap film

abstract:
  An experimental study of Taylor's hypothesis in a quasi-two-dimensional
turbulent soap film is presented. A two probe laser Doppler velocimeter enables
a non-intrusive simultaneous measurement of the velocity at spatially separated
points. The breakdown of Taylor's hypothesis is quantified using the cross
correlation between two points displaced in both space and time; correlation is
better than 90% for scales less than the integral scale. A quantitative study
of the decorrelation beyond the integral scale is presented, including an
analysis of the failure of Taylor's hypothesis using techniques from
predictability studies of turbulent flows. Our results are compared with
similar studies of 3D turbulence.


title: Post-Gaussian variational method for quantum anharmonic oscillator

abstract:
  Using the post-Gaussian trial functions, we calculate the variational
solutions to the quantum-mechanical anharmonic oscillator. We evaluate not only
the ground state but also some excited energies, and compare them with
numerical results.


title: A Piecewise-Conserved Constant of Motion for a Dissipative System

abstract:
  We discuss a piecewise-conserved constant of motion for a simple dissipative
oscillatory mechanical system. The system is a harmonic oscillator with sliding
(dry) friction. The piecewise-conserved constant of motion corresponds to the
time average of the energy of the system during one half-period of the motion,
and changes abruptly at the turning points of the motion. At late times the
piecewise-conserved constant of motion degenerates to a constant of motion in
the usual sense.


title: A Theory of Quantum Space-time

abstract:
  An interpretation and re-formulation of modern physics which removes the
presumption of the space-time continuum, and bases physical theory on a small
number of rational and empirical principles. After briefly describing the
philosophical principles underlying the theory, we rigorously construct a
discrete model of quantum mechanics. Kets are names, or labels which categorise
states of matter but do not directly describe them. The principle of
superposition is seen as a definitional truism in the categorisation of states.
This resolves the measurement problem of quantum mechanics by attributing the
collapse of the wave function to information. The probability interpretation
has a natural meaning in which the configuration of interacting particles plays
the role of a hidden variable. The model supports a form of relativistic
quantum field theory which does not depend on quantisation or second
quantisation from classical mechanics. Continuous laws of wave mechanics are
found in a discrete metaphysic which does not involve waves. Classical law is
the expected behaviour of many elementary particles. The constraints on the
theory are sufficient to establish that particles are point-like entities with
specific properties found in nature. Newton's first law and conservation of
momentum are established from the principle of homogeneity. Maxwell's equations
are derived from the simple interaction in which a Dirac particle emits or
absorbs a photon. Feynman rules are calculated for the discrete theory and
differ from the standard rules by the removal of the ultraviolet divergence and
the use of proper loop integrals. They give finite and unambiguous results.


title:
Collisionless Damping of Low-Frequency Magnetosonic Pulses in a
  Two-Ion-Species Plasma

abstract:
  Low-frequency mangnetosonic pulses in a two-ion-species plasma are studied
theoretically and by simulation with a one-dimensional electromagnetic
simulation code based on a three-fluid model, with particular attention to the
dynamics of minority heavy ions. It is found that heavy ions can gain some
energy from the pulses. Because of this energy transfer, the pulses are damped
even if the plasma is collisionless and pulse propagation is perpendicular to
the magnetic field.


title:
Quasi-classical Molecular Dynamics Simulations of the Electron Gas:
  Dynamic properties

abstract:
  Results of quasi-classical molecular dynamics simulations of the quantum
electron gas are reported. Quantum effects corresponding to the Pauli and the
Heisenberg principle are modeled by an effective momentum-dependent
Hamiltonian. The velocity autocorrelation functions and the dynamic structure
factors have been computed. A comparison with theoretical predictions was
performed.


title:
Electron acceleration to ultrarelativistic energies in a collisionless
  oblique shock wave

abstract:
  Electron motion in an oblique shock wave is studied by means of a
one-dimensional, relativistic, electromagnetic, particle simulation code with
full ion and electron dynamics. It is found that an oblique shock can produce
electrons with ultra-relativistic energies; Lorentz factors with $\gamma \gto
100$ have been observed in our simulations. The physical mechanisms for the
reflection and acceleration are discussed, and the maximum energy is estimated.
If the electron reflection occurs near the end of a large-amplitude pulse,
those particles will then be trapped in the pulse and gain a great deal of
energy. The theory predicts that the electron energies can become especially
high at certain propagation angles. This is verified by the simulations.


title: The Nonlinear Debye-Onsager Relaxation Effect in Weakly Ionized Plasmas

abstract:
  A weakly ionized plasma under the influence of a strong electric field is
considered. Supposing a local Maxwellian distribution for the electron momenta
the plasma is described by hydrodynamic equations for the pair distribution
functions. These equations are solved and the relaxation field is calculated
for an arbitrary field strength. It is found that the relaxation effect becomes
lower with increasing strength of the electrical field.


title: Proton structure effects in muonic hydrogen

abstract:
  The proton structure effects, including finite size, polarizability and
self-energy is considered and their influence on energy levels of muonic
hydrogen is recalculated. A new theoretical prediction for the Lamb shift is
presented together with improved values of all known QED contributions.


title: Scaling properties of three-dimensional magnetohydrodynamic turbulence

abstract:
  The scaling properties of three-dimensional magnetohydrodynamic turbulence
are obtained from direct numerical simulations of decaying turbulence using
$512^3$ modes. The results indicate that the turbulence does not follow the
Iroshnikov-Kraichnan phenomenology.In the case of hyperresistivity, the
structure functions exhibit a clear scaling range yielding absolute values of
the scaling exponents $\zeta_p$. The scaling exponents agree with a modified
She-Leveque model $\zeta_p=p/9 + 1 - (1/3)^{p/3}$, corresponding to Kolmogorov
scaling but sheet-like geometry of the dissipative structures.


title:
On the analytic expression that must be given to the gravitational
  tensor in Einstein's theory

abstract:
  Foreword. While most textbooks of general relativity and research articles
discuss at length the relative merits of the pseudo tensors proposed by
Einstein and by other authors for representing the energy of the gravitational
field, Levi Civita's definition of a true gravitational energy tensor has
succumbed to the authority of Einstein and is nearly forgotten. It seems
however worthy of a careful re-examination, due to its unquestionable logical
soundness and to the unique manner of propagation for gravitational energy that
it entails.


title:
Electronic entropy, shell structure, and size-evolutionary patterns of
  metal clusters

abstract:
  We show that electronic-entropy effects in the size-evolutionary patterns of
relatively small (as small as 20 atoms), simple-metal clusters become prominent
already at moderate temperatures. Detailed agreement between our
finite-temperature-shell-correction-method calculations and experimental
results is obtained for certain temperatures. This agreement includes a
size-dependent smearing out of fine-structure features, accompanied by a
measurable reduction of the heights of the steps marking major-shell and
subshell closings, thus allowing for a quantitative analysis of cluster
temperatures.


title: Effects of long-range dispersion in nonlinear dynamics of DNA molecules

abstract:
  A discrete nonlinear Schrodinger (NLS) model with long-range dispersive
interactions describing the dynamical structure of DNA is proposed. Dispersive
interactions of two types: the power dependence $r^{-s}$ and the exponential
dependence $e^{-\beta r}$ on the distance, $r$, are studied. For $s$ less than
some critical value, $s_{cr}$, and similarly for $\beta \leq \beta_{cr}$ there
is an interval of bistability where two stable stationary states: narrow,
pinned states and broad, mobile states exist at each value of the total energy.
For cubic nonlinearity the bistability of the solitons occurs for dipole-dipole
dispersive interaction $(s=3)$, and for the inverse radius of the dispersive
interaction $\beta \leq \beta_{cr}=1.67$. For increasing degree of
nonlinearity, $\sigma$, the critical values $s_{cr}$ and $\beta_{cr}$ increase.
The long-distance behavior of the intrinsically localized states depends on
$s$. For $s>3$ their tails are exponential while for $2<s<3$ they are
algebraic. A controlled switching between pinned and mobile states is
demonstrated applying a spatially symmetric perturbation in the form of a
parametric kick. The mechanism could be important for controlling energy
storage and transport in DNA molecules.


title: Models for energy and charge transport and storage in biomolecules

abstract:
  Two models for energy and charge transport and storage in biomolecules are
considered. A model based on the discrete nonlinear Schrodinger equation with
long-range dispersive interactions (LRI's) between base pairs of DNA is offered
for the description of nonlinear dynamics of the DNA molecule. We show that
LRI's are responsible for the existence of an interval of bistability where two
stable stationary states, a narrow, pinned state and a broad, mobile state,
coexist at each value of the total energy. The possibility of controlled
switching between pinned and mobile states is demonstrated. The mechanism could
be important for controlling energy storage and transport in DNA molecules.
Another model is offered for the description of nonlinear excitations in
proteins and other anharmonic biomolecules. We show that in the highly
anharmonic systems a bound state of Davydov and Boussinesq solitons can exist.


title:
Electron-impact ionization of atomic hydrogen from near threshold to
  high energies

abstract:
  Application of the convergent close-coupling (CCC) method to electron-impact
ionization of the ground state of atomic hydrogen is considered at incident
energies of 15.6, 17.6, 20, 25, 27.2, 30, 54.4, 150 and 250 eV. Total through
to fully differential cross sections are presented. Following the analysis of
Stelbovics [submitted to Phys. Rev. Lett. (physics/9905020)] the equal-energy
sharing cross sections are calculated using a solely coherent combination of
total-spin-dependent ionization amplitudes, which are found to be simply a
factor of two greater than the incoherent combination suggested by Bray and
Fursa [1996 Phys. Rev. A {\bf 54}, 2991]. As a consequence, the CCC theory is
particularly suited to the equal-energy-sharing kinematical region, and is able
to obtain convergent absolute scattering amplitudes, fully ab initio. This is
consistent with the step-function hypothesis of Bray [1997 Phys. Rev. Lett.
{\bf 78}, 4721], and indicates that at equal-energy-sharing the CCC amplitudes
converge to half the step size. Comparison with experiment is satisfactory in
some cases and substantial discrepancies are identified in others. The
discrepancies are generally unpredictable and some internal inconsistencies in
the experimental data are identified. Accordingly, new (e,2e) measurements are
requested.


title: Complete Numerical Solution of the Temkin-Poet Three-Body Problem

abstract:
  Although the convergent close-coupling (CCC) method has achieved
unprecedented success in obtaining accurate theoretical cross sections for
electron-atom scattering, it generally fails to yield converged energy
distributions for ionization. Here we report converged energy distributions for
ionization of H(1s) by numerically integrating Schroedinger's equation subject
to correct asymptotic boundary conditions for the Temkin-Poet model collision
problem, which neglects angular momentum. Moreover, since the present method is
complete, we obtained convergence for all transitions in a single calculation.
Complete results, accurate to 1%, are presented for impact energies of 54.4 and
40.8 eV, where CCC results are available for comparison.


title:
Analytic Confidence Level Calculations using the Likelihood Ratio and
  Fourier Transform

abstract:
  The interpretation of new particle search results involves a confidence level
calculation on either the discovery hypothesis or the background-only ("null")
hypothesis. A typical approach uses toy Monte Carlo experiments to build an
expected experiment estimator distribution against which an observed
experiment's estimator may be compared. In this note, a new approach is
presented which calculates analytically the experiment estimator distribution
via a Fourier transform, using the likelihood ratio as an ordering estimator.
The analytic approach enjoys an enormous speed advantage over the toy Monte
Carlo method, making it possible to quickly and precisely calculate confidence
level results.


title: Quasiclassical Theory and Simulations of Strongly Coupled Plasmas

abstract:
  A survey on the dynamical and thermodynamical properties of plasmas with
strong Coulomb interactions in the quasi-classical density-temperature region
is given. First the basic theoretical concepts describing nonideality are
discussed. The chemical picture is introduced. It is shown that the nonideal
plasma subsystem of the free charges has a rather large quasi-classical regime,
where the quantum effects yield only corrections to the merely classical
dynamics. The plasma of free charges may be described by effective potentials
which incorporate quantum effects in an approximative way. The simplest
effective potentials are only space-dependent, more advanced methods include
momentum-dependent interactions. On the basis of these potentials analytical
results are derived and simulation methods are developed. It is shown that
effective potentials are appropriate for the description of thermodynamical as
well as collective properties.


title: Artificial Neural Network Modeling of Forest Tree Growth

abstract:
  The problem of modeling forest tree growth curves with an artificial neural
network (NN) is examined. The NN parametric form is shown to be a suitable
model if each forest tree plot is assumed to consist of several differently
growing sub-plots. The predictive Bayesian approach is used in estimating the
NN output.
  Data from the correlated curve trend (CCT) experiments are used. The NN
predictions are compared with those of one of the best parametric solutions,
the Schnute model. Analysis of variance (ANOVA) methods are used to evaluate
whether any observed differences are statistically significant. From a
Frequentist perspective the differences between the Schnute and NN approach are
found not to be significant. However, a Bayesian ANOVA indicates that there is
a 93% probability of the NN approach producing better predictions on average.


title: Internal Vortex Structure of a Trapped Spinor Bose-Einstein Condensate

abstract:
  The internal vortex structure of a trapped spin-1 Bose-Einstein condensate is
investigated. It is shown that it has a variety of configurations depending on,
in particular, the ratio of the relevant scattering lengths and the total
magnetization.


title: Theory of Two Dimensional Mean Field Electron Magnetohydrodynamics

abstract:
  The theory of mean field electrodynamics for diffusive processes in Electron
Magnetohydrodynamic (EMHD) model is presented. In contrast to
Magnetohydrodynamics (MHD) the evolution of magnetic field here is governed by
a nonlinear equation in the magnetic field variables. A detailed description of
diffusive processes in two dimensions are presented in this paper. In
particular, it has been shown analytically that the turbulent magnetic field
diffusivity is suppressed from naive quasilinear estimates. It is shown that
for complete whisterlization of the spectrum, the turbulent diffusivity
vanishes. The question of whistlerization of the turbulent spectrum is
investigated numerically, and a reasonable tendency towards whisterlization is
observed. Numerical studies also show the suppression of magnetic field
diffusivity in accordance with the analytical estimates.


title: Integral cross sections for electron scattering by ground state Ba atoms

abstract:
  We have used the convergent close-coupling method and a unitarized
first-order many-body theory to calculate integral cross sections for elastic
scattering and momentum transfer, for excitation of the 5d^2 ^1S, 6s6p^1P_1,
6s7p^1P_1, 6s8p^1P_1, 6s5d^1D_2, 5d^2^1D_2, 6s6d^1D_2, 6p5d^1F_3, 6s4f^1F_3,
6p5d^1D_2, 6s6p^3P_{0,1,2}, 6s5d^3D_{1,2,3}, and 6p5d^3D_2 states, for
ionization and for total scattering by electron impact on the ground state of
barium at incident electron energies from 1 to 1000 eV. These results and all
available experimental data have been combined to produce a recommended set of
integral cross sections.


title: Electromagnetic modes in cold magnetized strongly coupled plasmas

abstract:
  The spectrum of electromagnetic waves propagating in a strongly coupled
magnetized fully ionized hydrogen plasma is found. The ion motion and damping
being neglected, the influence of the Coulomb coupling on the electromagnetic
spectrum is analyzed.


title:
Discrimination between Nuclear Recoils and Electron Recoils by
  Simultaneous Detection of Phonons and Scintillation Light

abstract:
  We have developed a detector, consisting of a cryogenic calorimeter with a
scintillating crystal as absorber, and a second calorimeter for the detection
of the scintillation light, both operated at 12 mK. Using a CaWO4 crystal with
a mass of 6g as scintillating absorber, we have achieved a discrimination of
nuclear recoils against electron recoils with a suppression factor of 99.7% at
energies above 15 keV. This novel method will be applied for background
rejection in the CRESST (Cryogenic Rare Event Search with Superconducting
Thermometers) experiment looking for dark matter Weakly Interacting Massive
Particles (WIMPs).


title:
Phase Diagram for Turbulent Transport: Sampling Drift, Eddy Diffusivity
  and Variational Principles

abstract:
  We study the long-time, large scale transport in a three-parameter family of
isotropic, incompressible velocity fields with power-law spectra. Scaling law
for transport is characterized by the scaling exponent $q$ and the Hurst
exponent $H$, as functions of the parameters. The parameter space is divided
into regimes of scaling laws of different {\em functional forms} of the scaling
exponent and the Hurst exponent. We present the full three-dimensional phase
diagram.
  The limiting process is one of three kinds: Brownian motion ($H=1/2$),
persistent fractional Brownian motions ($1/2<H<1$) and regular (or smooth)
motion (H=1).
  We discover that a critical wave number divides the infrared cutoffs into
three categories, critical, subcritical and supercritical; they give rise to
different scaling laws and phase diagrams. We introduce the notions of sampling
drift and eddy diffusivity, and formulate variational principles to estimate
the eddy diffusivity. We show that fractional Brownian motions result from a
dominant sampling drift.

categories: physics.flu-dyn math-ph math.MP physics.data-an


title: Mechanical models of physical fields and particles

abstract:
  Earlier obtained results on mechanical analogies of physical fields and
particles are reviewed. The approach rests on the concept of the substratum - a
mechanical medium, which occupies all the space and serves as a seat to support
the light and to transmit interactions. A turbulent ideal fluid was chosen for
the substratum. The turbulence is supposed to be homogeneous and isotropic in
its ground state. Perturbations of the turbulence model physical fields.
Particles originate from the voids in the fluid. Symmetrical pairs of
particle-antiparticle find analogies in mechanical pairs of
cyclone-anticyclone. A quantum particle is modeled by the dispersion of a point
discontinuity (defect) in the stochastic medium. Gravitation relates to
emitting by defects the continual flow of the transient point dilatation. The
shock wave mechanism of the re-collection a discontinuity in the incompressible
medium governs such phenomena as the "wave function collapse" and instantaneous
quantum correlations. Microscopically, the electromagnetic wave and gravitation
are modeled by the torsional and axisymmetric waves, respectively, in the
vortex sponge.


title:
Equation of states for classical Coulomb systems. The use of
  Hubbard-Schofield approach

abstract:
  An effective method based on Hubbard-Schofield approach [Phys. Lett. A {\bf
40}, 245 (1972)] is developed to calculate the free energy of classical Coulomb
systems. This method significantly simplifies the derivation of the cluster
expansion. A diagrammatic representation of the cluster integrals is proposed.
Simple rules providing the leading order in density $n$ of each diagrammatic
contribution are found. We calculate the $n^3$ contribution and recover the
results at the order $n^{5/2}$ obtained by the traditional method of
resummation of diverging Mayer bonds.


title: Linac-Ring Type phi Factory for Basic and Applied Researches

abstract:
  In this paper, main parameters for linac-ring type collider desinged for
producing $\phi $ particles copiously are estimated and potential of this
machine in particle physics researches is investigated. Moreover, parameters
for free electron laser and synchrotron radiation obtained from electron linac
and positron ring, respectively, are determined and applications of these
radiations are summarized.


title: Diffraction of X-ray pulse in crystals

abstract:
  The X-ray radiation delay law dependence on the diffraction asymmetry
parameters is analyzed. It is shown that the use of subpicosecond pulses allows
to observe the time delay of pulse in crystal phenomenon and to investigate the
delay law experimentally. It is also shown that pulse delay law depends on the
quanta polarization.


title: Determination of the fine structure constant by simple formula

abstract:
  In the report submitted here, an elementary formula is presented that allows
calculation of the fine structure constant, derived on the basis of the unified
theory of the electromagnetic and gravitational field elaborated by the author.
This theory is based on the laws of relativity and quantum mechanics, in a
brand new insight into the interpretation of gravitational forces. The electron
model designed by the author then offers a remarkable reply to the problem of
the electric charge essence. A direct implication of this theory is the
functional dependence of the charge upon the Planck constant and the speed of
light, therefore the fine structure constant can be identified with arbitrary
numerical accuracy. There is no visible difference between the presented value
of this constant and the experimental result stemming from the area related in
a way to this theory, the quantum Hall effect.


title:
Corpuscular Interpretation of Mikroparticle Diffraction and Possible
  Experimental Test

abstract:
  We examine the logical difficulties that arise when a particle(wave)
interferes with itself. We propose to carry out to its full extent a `gedanken'
experiment originally proposed by Feynman in order to give an unequivocal
experimental proof of the correctness of the wave representation. As an
example, we give a corpuscular interpretation of the diffraction pattern.


title: Search for exchange-antisymmetric two-photon states

abstract:
  Atomic two-photon J=0 $\leftrightarrow$J'=1 transitions are forbidden for
photons of the same energy. This selection rule is related to the fact that
photons obey Bose-Einstein statistics. We have searched for small violations of
this selection rule by studying transitions in atomic Ba. We set a limit on the
probability $v$ that photons are in exchange-antisymmetric states:
$v<1.2\cdot10^{-7}$.


title:
Comment on "Density functional theory study of some structural and
  energetic properties of small lithium clusters" [J. Chem. Phys. 105, 9933
  (1996)]

abstract:
  The Ionization Potentials of small Li_N clusters are calculated with a Shell
Correction Method. They are used to illustrate that, within the jellium
approximation, deformed cluster shapes provide an adequate description of the
observed systematic size dependence of the properties of simple metal clusters.
Such deformation effects were overlooked in the analysis of Gardet et al.


title: Self-Pulsating Semiconductor Lasers: Theory and Experiment

abstract:
  We report detailed measurements of the pump-current dependency of the
self-pulsating frequency of semiconductor CD lasers. A distinct kink in this
dependence is found and explained using rate-equation model. The kink denotes a
transition between a region where the self-pulsations are weakly sustained
relaxation oscillations and a region where Q-switching takes place. Simulations
show that spontaneous emission noise plays a crucial role for the cross-over.


title: MY LIFE AS TUTOR: Reflections on Two Recent Experiences

abstract:
  In this final report, I briefly reflect on two parallel teaching experiences
as tutor. Besides, I briefly view such experiences in interaction with my
research work, private life and new teaching position. In harmony with my
conception of teaching, I avoid the standard formal style of reports and try an
interactive dialogue with the reader.


title: Strong Coupling Theory of Two Level Atoms in Periodic Fields

abstract:
  We present a new convergent strong coupling expansion for two-level atoms in
external periodic fields, free of secular terms. As a first application, we
show that the coherent destruction of tunnelling is a third-order effect. We
also present an exact treatment of the high-frequency region, and compare it
with the theory of averaging. The qualitative frequency spectrum of the
transition probability amplitude contains an effective Rabi frequency.

categories: physics.atom-ph physics.gen-ph physics.optics quant-ph


title: An Interpretation of Quantum Logic

abstract:
  It is argued that the orthodox interpretation of quantum mechanics is in
conflict with the objective existence of space-time, and suggested that kets
are labels which name real states of matter but do not directly describe them.
Position is a relationship between particles which necessarily contains
uncertainty. The principle of superposition is seen as a definitional truism in
the naming of states. The description of space in quantum logic resolves the
measurement problem of quantum mechanics and related paradoxes such as
Schrodinger's cat by attributing the collapse of the wave function to
information.


title: The Problem of the Age of the Universe and the Earliest Galaxies

abstract:
  A number of years ago the estimates of astronomers and astrophysicists were
that the earliest galaxies took about 2.5 to 3 billion years to form, that is,
that they did not appear until 2.5 to 3 billion years after the Big Bang. Those
estimates were based on analysis of the processes involved in star formation
and in the aggregation and "clumping" of matter in the early universe.
  Since then improved equipment and techniques, e.g. Keck and Hubble telescopes
and gravitational lensing, have resulted in reports of observation of early
galaxies having stars that formed as early as 300 million years after the Big
Bang.
  Such new data has led to the abandonment of the several billion years
estimates of the time required for star and galaxy formation; however, an
alternative response to the data would be to re-examine the Hubble theory from
which the age of the universe and the distance to high redshift objects is
determined.


title: Classical Electron Theory and Conservation Laws

abstract:
  It is shown that the traditional conservation laws for total charge, energy,
linear and angular momentum, hold jointly in classical electron theory if and
only if classical electron spin is included as dynamical degree of freedom.


title: Spin-resolved electron-impact ionization of lithium

abstract:
  Electron-impact ionization of lithium is studied using the convergent
close-coupling (CCC) method at 25.4 and 54.4 eV. Particular attention is paid
to the spin-dependence of the ionization cross sections. Convergence is found
to be more rapid for the spin asymmetries, which are in good agreement with
experiment, than for the underlying cross sections. Comparison with the recent
measured and DS3C-calculated data of Streun et al (1999) is most intriguing.
Excellent agreement is found with the measured and calculated spin asymmetries,
yet the discrepancy between the CCC and DS3C cross sections is very large.


title:
Photoinduced optical rotation in a racemic mixture of hydrogen peroxide
  molecules

abstract:
  A problem of inducing a required sign of chirality in a racemic mixture of
enantiomers of a chiral molecule is analyzed. As an example, a racemic mixture
(vapor) of left- and right-handed enantiomers of hydrogen peroxide (H2O2)
molecule is considered. It is shown that biharmonic Raman excitation of the
splitted due to the left-right conversion internal rotation levels can be
effectively used for inducing optical activity in the initially racemic vapor
of H2O2 molecules. An experiment to study this photoinduced optical rotation is
discussed.


title: Time Series Forecasting: A Nonlinear Dynamics Approach

abstract:
  The problem of prediction of a given time series is examined on the basis of
recent nonlinear dynamics theories. Particular attention is devoted to forecast
the amplitude and phase of one of the most common solar indicator activity, the
international monthly smoothed sunspot number. It is well known that the solar
cycle is very difficult to predict due to the intrinsic complexity of the
related time behaviour and to the lack of a succesful quantitative theoretical
model of the Sun magnetic cycle. Starting from a previous recent work, we
checked the reliability and accuracy of a forecasting model based on concepts
of nonlinear dynamical systems applied to experimental time series, such as
embedding phase space, Lyapunov spectrum, chaotic behaviour. The model is based
on a local hypothesis of the behaviour on the embedding space, utilizing an
optimal number k of neighbour vectors to predict the future evolution of the
current point with the set of characteristic parameters determined by several
previous parametric computations. The performances of this method suggest its
valuable insertion in the set of the so-called statistical-numerical prediction
techniques, like Fourier analyses, curve fitting, neural networks,
climatological, etc. The main task is to set up and to compare a promising
numerical nonlinear prediction technique, essentially based on an inverse
problem, with the most accurate predictive methods like the so-called
"precursor methods" which appear now reasonably accurate in predicting "long
term" Sun activity, with particular reference to the "solar" precursor methods
based on a solar dynamo theory.

categories: physics.data-an astro-ph chao-dyn nlin.CD


title:
Lasing on the D_2 line of sodium in helium atmosphere due to optical
  pumping on the D_1 line (up-conversion)

abstract:
  A new method is proposed to produce population inversion on transitions
involving the ground state of atoms. The method is realized experimentally with
sodium atoms. Lasing at the frequency corresponding to the sodium D_2 line is
achieved in the presence of pump radiation resonant to the D_1 line with helium
as a buffer gas.


title:
Accurate ab initio anharmonic force field and heat of formation for
  silane, SiH_4

abstract:
  From large basis set coupled cluster calculations and a minor empirical
adjustment, an anharmonic force field for silane has been derived that is
consistently of spectroscopic quality ($\pm 1 cm^{-1}$ on vibrational
fundamentals) for all isotopomers of silane studied. Inner-shell polarization
functions have an appreciable effect on computed properties and even on
anharmonic corrections. From large basis set coupled cluster calculations and
extrapolations to the infinite-basis set limit, we obtain TAE_0=303.80 \pm 0.18
kcal/mol, which includes an anharmonic zero-point energy (19.59 kcal/mol),
inner-shell correlation (-0.36 kcal/mol), scalar relativistic corrections
(-0.70 kcal/mol), and atomic spin-orbit corrections (-0.43 kcal/mol). In
combination with the recently revised \HVSI{0}, we obtain $\Delta
H^{\circ}_{f,0}[SiH_4(g)]=9.9 \pm 0.4 kcal/mol$, in between the two established
experimental values.


title: Optics of Nonuniformly Moving Media

abstract:
  A moving dielectric appears to light as an effective gravitational field. At
low flow velocities the dielectric acts on light in the same way as a magnetic
field acts on a charged matter wave. We develop in detail the geometrical
optics of moving dispersionless media. We derive a Hamiltonian and a Lagrangian
to describe ray propagation. We elucidate how the gravitational and the
magnetic model of light propagation are related to each other. Finally, we
study light propagation around a vortex flow. The vortex shows an optical
Aharonov--Bohm effect at large distances from the core, and, at shorter ranges,
the vortex may resemble an optical black hole.


title: Water temperature constraint on Sonoluminescence

abstract:
  It is proposed that shock wave dynamics within the gas of a small bubble
explain sonoluminescence, the emission of visible radiation. As the bubble
radius oscillates, shock waves develop from spherical sound waves created
inside the gas bubble. As any such shock propagates toward the center, it
strengthens and, upon convergence and subsequent reflection, temperature of gas
inside bubble increases dramatically in such a way that it can produce plasma.
Since main radiation product in exploding epoch, nonadiabatic condition for
imploding shock wave cool plasma and cause exploding shock wave can not
sufficiently rise temperature to produce radiation. In this work we compare
cooling time for plasma by bermsstrahlung radiation with collapsing time for
the imploding shock wave . We find a constraint on radius of bubble with
respect to temperature of water. This constraint condition explains
experimental results as to, why the cold water is fine for SL.


title: Night Thoughts of a Quantum Physicist

abstract:
  The most dramatic developments in theoretical physics in the next millennium
are likely to come when we make progress on so far unresolved foundational
questions. In this essay I consider two of the deepest problems confronting us,
the measurement problem in quantum theory and the problem of relating
consciousness to the rest of physics. I survey some recent promising ideas on
possible solutions to the measurement problem and explain what a proper
physical understanding of consciousness would involve and why it would need new
physics.


title:
Electron Collisional Broadening of Isolated Lines from Multiply-Ionized
  Atoms

abstract:
  Recent experimental and theoretical (both improved semiclassical and fully
quantum-mechanical) results for B III and Ne VII delta n = 0 transitions with n
= 2 or 3, respectively, are discussed. The probable reasons for disagreements
by about a factor of 2 between the fully quantum-mechanically calculated and
both measured and semiclassically calculated widths can be explained in terms
of violation of validity criteria and non-thermal Doppler effects. More
independent determinations of line widths for multiply-ionized non-hydrogenic
ions are called for, but meanwhile caution should be exercised in the use of
corresponding semiclassically calculated widths, e.g., in opacity calculations
or for plasma density diagnostics. Only the quantum calculations allow a clear
separation of elastic and inelastic scattering contributions to the width. For
B III, elastic scattering contributes about 30% whereas for Ne VII inelastic
scattering dominates. This allows rather direct comparisons with benchmark
electron-ion scattering experiments.


title: The Fabric of Space-time

abstract:
  The formulae of special relativity are developed through the k-calculus with
no presumption of a manifold. The metric is determined empirically by the
exchange of photons, and the treatment suggests that the exchange of photons
seen in quantum electrodynamics is also responsible for the 'fabric' of
Minkowsky space-time. This suggests that on quantum scales the point-like
nature of elementary particles, should appear 'defocussed' or 'fuzzy'. Further
work on the implications in the laws of physics is referred to


title: Large deviations from the thermodynamic limit in globally coupled maps

abstract:
  Systems of a large number N of globally coupled maps have become popular as a
relatively simple prototype of high-dimensional dynamics, showing many
interesting and typical phenomena like synchronisation, cluster formation and
multistability, and having potential applications in systems like Josephson
junction arrays or in biophysical models. There exists a wealth of numerical
investigations of globally coupled maps. While much progress has been made in
the explanation of the macroscopic behaviour of such systems in the limit of
infinite N, there is still need for a sound theory about the asymptotic
behaviour of finite-N systems as N approaches infinity. This article introduces
a method by which it is possible to obtain asymptotic estimates for long-term
deviations from the thermodynamic limit behaviour. This method is based upon
the concept of quasipotentials, originally developed by Freidlin, Wentzell, and
others for describing the influence of small random perturbations on the
long-term behaviour of dynamical systems. The problems of explicitly computing
quasipotentials in the present context and potential approximation schemes are
discussed. All the concepts described in this article are illustrated with a
simple example.


title:
Relativistic many-body calculations of energy levels, hyperfine
  constants, electric-dipole matrix elements and static polarizabilities for
  alkali-metal atoms

abstract:
  Removal energies and hyperfine constants of the lowest four $ns, np_{1/2}$
and $np_{3/2}$ states in Na, K, Rb and Cs are calculated; removal energies of
the n=7--10 states and hyperfine constants of the n=7 and 8 states in Fr are
also calculated. The calculations are based on the relativistic single-double
(SD) approximation in which single and double excitations of Dirac-Hartree-Fock
(DHF) wave functions are included to all-orders in perturbation theory. Using
SD wave functions, accurate values of removal energies, electric-dipole matrix
elements and static polarizabilities are obtained, however, SD wave functions
give poor values of magnetic-dipole hyperfine constants for heavy atoms. To
obtain accurate values of hyperfine constants for heavy atoms, we include
triple excitations partially in the wave functions. The present calculations
provide the basis for reevaluating PNC amplitudes in Cs and Fr.


title: Enhancement of parity and time invariance violation in Radium atom

abstract:
  There are several factors which lead to a huge enhancement of parity and time
invariance violating effects in the Ra atom: very close electronic levels of
opposite parity, the large nuclear charge Z and the collective nature of
T,P-odd nuclear moments. Experiments with Radium may be used to measure it's
nuclear anapole, magnetic quadrupole and Schiff moments. Such measurements
provide information about parity and time invariance violating nuclear forces
and electron-nucleon interactions.


title: Atomic Compton profiles within different exchange-only theories

abstract:
  The Impulse Compton Profiles (CP's) J(q) and the <p^n> - expectation values
for some inert gas atoms (He-Kr) are computed and compared within the
Harbola-Sahni (HS), Hartree-Fock(HF) theories and a Self Interaction Corrected
(SIC) density functional model. The Compton profiles for excited states of
Helium atom are also calculated. While the calculated CP's are found to
generally agree, they differ slightly from one another for small values of the
Compton parameter q and are in good agreement for large q values. The <p^n>
expectation values within the three theories are also found to be comparable.
The HS formalism seem to mimic HF reasonably well in the momentum space,
establishing the logical consistency of the former.


title:
Positron and positronium affinities in the work-formalism Hartree-Fock
  approximation

abstract:
  Positron binding to anions is investigated within the work formalism proposed
by Harbola and Sahni for the halide anions and the systems Li^- through O^-
excluding Be^- and N^-. The toal ground-state energies of the anion-positron
bound systems are empirically found to be an upper bound to the Hartree-Fock
energies. The computed expectation values as well as positron and positronium
affinities are in good agreement with their restricted Hartree-Fock
counterparts. Binding of a positron to neutral species is also investigated
using an iterative method.


title: Overcoming priors anxiety

abstract:
  The choice of priors may become an insoluble problem if priors and Bayes'
rule are not seen and accepted in the framework of subjectivism. Therefore, the
meaning and the role of subjectivity in science is considered and defended from
the pragmatic point of view of an ``experienced scientist''. The case for the
use of subjective priors is then supported and some recommendations for routine
and frontier measurement applications are given. The issue of reference priors
is also considered from the practical point of view and in the general context
of ``Bayesian dogmatism''.


title: Calculation of the positron bound state with the copper atom

abstract:
  A new relativistic method for calculation of positron binding to atoms is
presented. The method combines a configuration interaction treatment of the
valence electron and the positron with a many-body perturbation theory
description of their interaction with the atomic core. We apply this method to
positron binding by the copper atom and obtain the binding energy of 170 meV (+
- 10%). To check the accuracy of the method we use a similar approach to
calculate the negative copper ion. The calculated electron affinity is 1.218
eV, in good agreement with the experimental value of 1.236 eV. The problem of
convergence of positron-atom bound state calculations is investigated, and
means to improve it are discussed. The relativistic character of the method and
its satisfactory convergence make it a suitable tool for heavier atoms.


title: A Simpler Eulerian Variational Principle for Barotropic Fluids

abstract:
  The variational principle of barotropic Eulerian fluid dynamics is known to
be quite cumbersome containing as much as eleven independent functions. This is
much more than the the four functions (density and velocity) appearing in the
Eulerian equations of motion. This fact may have discouraged applications of
the variational method. In this paper a four function Eulerian variational
principle is suggested and the implications are discussed briefly.