title: A Study of the Energy Efficiency of Hadronic Reactors of Molecular Type

abstract:
  In this paper, we introduce an estimate of the "commercial efficiency" of
Santilli's hadronic reactors of molecular type (Patented and International
Patents Pending) which convert a liquid feedstock (such as automotive
antifreeze and oil waste, city or farm liquid waste, crude oil, etc.) into the
clean burning magnegas plus heat acquired by the liquid feedstock. The
"commercial efficiency" is defined as the ratio between the total energy output
(energy in magnegas plus heat) and the electric energy used for its production,
while the "scientific efficiency" is the usual ratio between the total energy
output and the total energy input (the sum of the electric energy plus the
energy in the liquid feedstock as well as that in the carbon electrodes). A
primary purpose of this paper is to show that conventional thermochemistry does
indeed predict a commercial efficiency bigger than one, although their values
is considerably smaller than the actual efficiency measured in the reactors,
thus indicating the applicability of the covering hadronic chemistry from which
the reactors have received their name. We reach an upper limit of the
commercial efficiency of 3.11 for the use of pure water as feedstock, and of
3.11 to 7.5 for a mixture of ethyleneglicole and water. The study of the heat
produced by the reactions leads to large divergencies between the
thermochemical predictions and experimental data of at least a factor of three.
Such divergencies can only be explained with deviations from quantum chemistry
in favor of the covering hadronic chemistry. In particular, the indicated large
divergencies can only be explained with the assumption that the produced
combustible gas has the new non-valence chemical structure of Santilli
magnecules.


title: A Study of Polycarbonyl Compounds in Magnegases

abstract:
  In this paper we study the structure and thermochemical properties of some
new polycarbonyl compounds, with particular attention devoted to the study of
(CO)$_n$ complexes, which are expected to be present in magnegases^TM. The
latter are anomalous gases produced by Hadronic Reactors^TM of molecular type
[2] (Patented and International Patents Pending) which expose atoms to the
extremely intense electronmagnetic fields existing at atomic distances from
electric arcs in such a way to create a toroidal distribution of the orbitals
of individual atoms, whether isolated or part of a valence bond. Polarized
atoms, dimers and molecules then attract each other via opposing magnetic
polarities resulting into stable clusters which constitute a new chemical
species called Santilli's magnecules [2]. Some of the numerous open problems in
the study of this intriguing new chemical species are pointed out.


title:
Beyond the poor man's implementation of unconditionally stable
  algorithms to solve the time-dependent Maxwell Equations

abstract:
  For the recently introduced algorithms to solve the time-dependent Maxwell
equations (see Phys.Rev.E Vol.64 p.066705 (2001)), we construct a variable grid
implementation and an improved spatial discretization implementation that
preserve the property of the algorithms to be unconditionally stable by
construction. We find that the performance and accuracy of the corresponding
algorithms are significant and illustrate their practical relevance by
simulating various physical model systems.


title: Adaptive sampling by information maximization

abstract:
  The investigation of input-output systems often requires a sophisticated
choice of test inputs to make best use of limited experimental time. Here we
present an iterative algorithm that continuously adjusts an ensemble of test
inputs online, subject to the data already acquired about the system under
study. The algorithm focuses the input ensemble by maximizing the mutual
information between input and output. We apply the algorithm to simulated
neurophysiological experiments and show that it serves to extract the ensemble
of stimuli that a given neural system ``expects'' as a result of its natural
history.


title:
Measurement of the 6s - 7p transition probabilities in atomic cesium and
  a revised value for the weak charge Q_W

abstract:
  We have measured the 6s - 7p_{1/2,3/2} transition probabilities in atomic
cesium using a direct absorption technique. We use our result plus other
previously measured transition rates to derive an accurate value of the vector
transition polarizability \beta and, consequently, re-evaluate the weak charge
Q_W. Our derived value Q_W=-72.65(49) agrees with the prediction of the
standard model to within one standard deviation.


title: Polarizabilities of germanium clusters

abstract:
  Polarizabilities of Ge$_n$ clusters with 2 to 25 atoms are calculated using
coupled-perturbation Hartree-Fock (CPHF) and finite field (FF) method within
density functional theory. The polarizabilities of the Ge$_n$ clusters increase
rapidly in the size range of 2 to 5 atoms and then fluctuate around the bulk
value. The polarizabilities are sensitively dependent on the cluster geometries
and electronic structures. The large HOMO-LUMO gap may lead to the small
polarizability. As compared with the compact structure and diamond structure,
the prolate cluster structure corresponds to a larger polarizability.


title:
Improved alternating gradient transport and focusing of neutral
  molecules

abstract:
  Polar molecules, in strong-field seeking states, can be transported and
focused by an alternating sequence of electric field gradients that focus in
one transverse direction while defocusing in the other. We show, by calculation
and numerical simulation, how one may greatly improve the alternating gradient
transport and focusing of molecules. We use a new optimized multipole lens
design, a FODO-lattice beam transport line, and lenses to match the beam
transport line to the beam source and to the final focus.
  We derive analytic expressions for the potentials, fields, and gradients that
may be used to design these lenses. We describe a simple lens optimization
procedure and derive the equations of motion for tracking molecules through a
beam transport line. As an example, we model a straight beamline that
transports a 560 m/s jet-source beam of methyl fluoride15 m from its source and
focuses it to 2 mm diameter. We calculate the beam transport line acceptance
and beam survival, for a beam with a velocity spread, and estimate the
transmitted intensity for specified source conditions. Possible applications
are discussed.


title: Enrichment of nuclear spin isomers by molecular coherent control

abstract:
  Enrichment of nuclear spin isomers of molecules by infrared radiation
resonant to molecular rovibrational transition is considered. Special attention
is given to the enrichment by light-induced crossing of far separated ortho and
para states.


title:
Novel structures of Co-Cu bimetallic clusters and their magnetic
  properties

abstract:
  The structural and magnetic properties of Co$_{18-m}$Cu$_m$ ($0\leq m\leq
18$) clusters are investigated with a genetic algorithm and a $spd$-band model
Hamiltonian in the unrestricted Hartree-Hock approximation respectively. In
general, Cu atoms tend to occupy the surface, while Co atoms prefer to the
interior of the clusters. Layered structures appear in some clusters with given
stoichiometric compositions. The introduction of Cu atoms leads to large
increase of the magnetic moment of Co-rich circumstance and nearly zero
magnetism of the Cu-rich ambient. The interaction between Cu and Co atoms
induces nonzero magnetic moment for Cu atoms. The total magnetic moments tend
to decrease with the increase of Cu atoms. However, some particular large
magnetic moment are found to be closely related to the structures. The
environment of Cu and Co atoms have a dominant effect on the magnetism of the
cluster.


title:
High-harmonic generation and periodic level crossings: time profile and
  control

abstract:
  We investigate high-harmonic generation in closed systems, using the
two-level atom as a simplified model. By means of a windowed Fourier transform
of the time-dependent dipole acceleration, we extract the main contributions to
this process within a cycle of the driving field. We show that the patterns
obtained can be understood by establishing a parallel between the two-level
atom and the three-step model. In both models, high-harmonic generation is a
consequence of a three-step process, which involves either the continuum and
the ground state, or the adiabatic states of the two-level Hamiltonian. The
knowledge of this physical mechanism allows us to manipulate the adiabatic
states, and consequently the harmonic spectra, by means of a bichromatic
driving field. Furthermore, using scaling laws, we establish sharp criteria for
the invariance of the physical quantities involved. Consequently, our results
can be extended to a broader parameter range, as for instance those
characteristic of solid-state systems in strong fields.


title: Fermi and the Elucidation of Matter

abstract:
  Fermi helped establish a new framework for understanding matter, based on
quantum theory. This framework refines and improves traditional atomism in two
crucial respects. First, the elementary constituents of matter belong to a very
small number of classes, and all objects of a given class (e.g., all electrons)
are rigorously identical, indeed indistinguishable. This profound identity is
demonstrated empirically through the phenomena of quantum statistics, and is
explained by the principles of free quantum field theory. Second, objects of
one class can mutate into objects of other classes. Such mutability can be
understood as manifesting interacting quantum field theory. Fermi contributed
to establishing theoretical foundations for the new viewpoint, through his work
on quantum statistics and quantum field theory, and to its fruitful application
and empirical validation, through his work on beta decay, nuclear
transmutation, and primeval strong interaction theory.


title:
A cluster partitioning method: determination of density matrices of
  solids and comparison with X-ray experiments

abstract:
  In this paper we show that 1-electron properties such as Compton profiles and
structure factors of crystals can be asymptotically retrieved through
cluster-based calculations, followed by an appropriate partition of the
1-electron reduced density matrix (1RDM). This approach, conceptually simple,
is checked with respects to both position and momentum spaces simultaneously
for insulators and a covalent crystal. Restricting the calculations to small
clusters further enables a fair description of local correlation effects in
ionic compounds, which improves both Compton profiles and structure factors vs.
their experimentally determined counterparts.

categories: physics.chem-ph cond-mat.mtrl-sci physics.atm-clus physics.atom-ph physics.comp-ph


title:
Angular versus radial correlation effects on momentum distributions of
  light two-electron ions

abstract:
  We investigate different correlation mechanisms for two-electron systems and
compare their respective effects on various electron distributions. The
simplicity of the wave functions used allows for the derivation of closed-form
analytical expressions for all electron distributions. Among other features, it
is shown that angular and radial correlation mechanisms have opposite effects
on Compton profiles at small momenta.

categories: physics.chem-ph cond-mat.mtrl-sci cond-mat.str-el physics.atm-clus physics.atom-ph


title:
Optimising the linear collider luminosity: feedback on nanosecond
  timescales

abstract:
  I summarise the R&D programme on a nanosecond-timescale fast-feedback system
for luminosity optimisation at the linear collider


title: A Gravitational Shielding Based on ZnS:Ag Phosphor

abstract:
  It was shown that there is a practical possibility of gravity control on
electroluminescent (EL) materials (physics/0109060). We present here a type
Gravitational Shielding based on an EL phosphor namely zinc sulfide doped with
silver (ZnS:Ag) which can reduce the cost of the Gravitational Motor previously
presented.


title: Quantum approach to the halo formation in high current beams

abstract:
  An interpretation of the formation of halo in accelerators based on
quantum-like theory by a diffraction model is given in terms of the transversal
beam motion. Physical implications of the longitudinal dynamics are also
examined


title:
Physical Constraints and Functional Characteristics of Transcription
  Factor-DNA Interaction

abstract:
  We study theoretical ``design principles'' for transcription factor-DNA
interaction in bacteria, focusing particularly on the statistical interaction
of the transcription factors (TF's) with the genomic background (i.e., the
genome without the target sites). We introduce and motivate the concept of
`programmability', i.e. the ability to set the threshold concentration for TF
binding over a wide range merely by mutating the binding sequence of a target
site. This functional demand, together with physical constraints arising from
the thermodynamics and kinetics of TF-DNA interaction, leads us to a narrow
range of ``optimal'' interaction parameters. We find that this parameter set
agrees well with experimental data for the interaction parameters of a few
exemplary prokaryotic TF's. This indicates that TF-DNA interaction is indeed
programmable. We suggest further experiments to test whether this is a general
feature for a large class of TF's.


title: An Exactly Conservative Integrator for the n-Body Problem

abstract:
  The two-dimensional n-body problem of classical mechanics is a non-integrable
Hamiltonian system for n > 2. Traditional numerical integration algorithms,
which are polynomials in the time step, typically lead to systematic drifts in
the computed value of the total energy and angular momentum. Even symplectic
integration schemes exactly conserve only an approximate Hamiltonian. We
present an algorithm that conserves the true Hamiltonian and the total angular
momentum to machine precision. It is derived by applying conventional
discretizations in a new space obtained by transformation of the dependent
variables. We develop the method first for the restricted circular three-body
problem, then for the general two-dimensional three-body problem, and finally
for the planar n-body problem. Jacobi coordinates are used to reduce the
two-dimensional n-body problem to an (n-1)-body problem that incorporates the
constant linear momentum and center of mass constraints. For a four-body
choreography, we find that a larger time step can be used with our conservative
algorithm than with symplectic and conventional integrators.


title: Quantum mechanical formalism of particle beam optics

abstract:
  A general procedure for construction of the formalism of quantum beam optics
for any particle is reviewed. The quantum formalism of spin-1/2 particle beam
optics is presented starting {\em ab initio} with the Dirac equation. As an
example of application the case of normal magnetic quadrupole lens is
discussed. In the classical limit the quantum formalism leads to the well-known
Lie algebraic formalism of classical particle beam optics.

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


title: The world of synchrotrons

abstract:
  A summary of results on synchrotron radiation is presented along with notes
on its properties and applications. Quantum aspects are briefly mentioned.
Synchrotron radiation facilities are described briefly with a detailed coverage
to the accelerator programmes in India. The relocated and other upcoming
synchrotrons are also described in some detail.


title: Theory of Quantum Electrodynamical Self-consistent Fields

abstract:
  To obtain the basis for combining various many-body techniques to QED in a
consistent manner, we investigate the theory of quantum electrodynamical
self-consistent fields. The reserch interest was born mainly of the electronic
structure theory, thus we consider of atomic and moleculer systems as our main
subjects. But the formalism is more fundamental. First, we derive the quantum
electrodynamical Hartree-Fock theory by using the Green's function method. Then
we construct a relativistic Hamiltonian written by creation-annihilation
operators for electron and positron in a general form, and check that it
reproduces the Hartree-Fock theory. We use this Hamiltonian to derive the
time-dependent Hartree-Fock theory and random phase approximation, in the
operator formalism. The relativistic Slater determinant of the Thouless
parametrization is also used. Finally we discuss the applications and futher
possible developments.


title:
Quantum Electrodynamical Density-matrix Functional Theory and
  Group-theoretical Consideration of its Solution

abstract:
  For studying the group theoretical classification of the solutions of the
density functional theory in relativistic framework, we propose quantum
electrodynamical density-matrix functional theory (QED-DMFT). QED-DMFT gives
the energy as a functional of a local one-body $4\times4$ matrix $Q(x)\equiv
-<\psi(x)\bar{\psi}(x)>$, where $\psi$ and $\bar{\psi}$ are 4-component Dirac
field and its Dirac conjugate, respectively. We examine some characters of
QED-DMFT. After these preparations, by using Q(x), we classify the solutions of
QED-DMFT under O(3) rotation, time reversal and spatial inversion. The behavior
of Q(x) under nonrelativistic and ultrarelativistic limits are also presented.
Finally, we give plans for several extensions and applications of QED-DMFT.

categories: physics.chem-ph hep-ph hep-th nucl-th physics.atom-ph


title: QED-SCF, MCSCF and Coupled-cluster Methods in Quantum Chemistry

abstract:
  We investigate the method to combine the techniques of quantum chemisty with
QED. In our theory, we treat the N-electron system and the Dirac sea on an
equal footing; we regard both of them as the dynamical degrees of freedom of a
many-body system. After the introduction of our QED-SCF method, the QED-SCF
solutions are classified into several classes on the basis of group-theoretical
operations such as time reversal, parity and O(3) rotational symmetry. The
natural orbitals of general QED-SCF solutions are determined by diagonalizing
the first order density matrix. Thus, we obtain the possibility to treat the
system under strong QED effect by the methods of quantum chemistry, such as
QED-MCSCF and QED-coupled-cluster approaches.


title:
Multi-Color Polarimetry of the Twilight Sky. The Role of Multiple
  Scattering as the Function of Wavelength

abstract:
  This work is devoted to the study of solar light that experiences single and
multiple scattering in the atmosphere at the twilight time. The work is based
on polarimetric observations of the twilight sky that were conducted in 1997
and 2000 for different color bands. Basing on the results of observations, the
contribution of single-scattered light depending on the wavelength for the
light stage of twilight is obtained. The correlation of color and polarization
properties of the twilight sky is investigated with an account of multiple
scattering


title:
Long-lived filaments in fusion plasmas: review of observations and
  status of hypothesis of microdust-assembled skeletons

abstract:
  A brief review is given of the progress in studying the long-lived filaments
(LLFs) in fusion plasmas (tokamaks, Z-pinch, plasma focus). The paper reports
on (i) resolving the fine structure of LLFs, and (ii) verification of our
hypothesis (1998) which suggested the LLFs to possess a microsolid skeleton.
The recent proof-of-concept studies showed the presence of tubular and
cartwheel-like structures in (i) various dust deposits in tokamak T-10, in the
range 10 nm - 10 mcm, and (ii) visible light images of plasma, in the range 100
mcm - 10 cm, at initial stage of discharge (e.g., before appearance of
discharge electric current) in tokamak, plasma focus and vacuum spark. The
topological similarity of the above structures (especially, "cartwheels") and
the observed trend of assembling bigger tubules from smaller ones (i.e. the
self-similarity) allow to draw a bridge between the microdust skeletons in the
dust deposits and the centimeter scale LLFs in fusion plasmas.


title:
Anomalous attenuation of extraordinary waves in ionosphere heating
  experiments: experimental results of 2000-2001

abstract:
  Multiple scattering from artificial random irregularities HF-induced in the
ionosphere F region causes significant attenuation of both ordinary and
extraordinary radio waves together with the conventional anomalous absorption
of ordinary waves due to their conversion into the plasma waves. To study in
detail features of this effect, purposeful measurements of the attenuation of
weak probing waves of the extraordinary polarization have been performed at the
Sura heating facility. Characteristic scale lengths of the involved
irregularities are ~0.1-1 km across the geomagnetic field lines. To determine
the spectral characteristics of these irregularities from the extraordinary
probing wave attenuation measurements, a simple procedure of the inverse
problem solving has been implemented and some conclusions about the artificial
irregularity features have been drawn. Theory and details of experiments have
been stated earlier. This paper reports results of two experimental campaigns
carried out in August 2000 and June 2001 under support of Russian Foundation
for Basic Research (grants No. 99-02-17525 and No. 01-02-31008). Particularity
of these experiments consisted in using of lower heating power (20-80 MW ERP).
Regular character of the multiple scattering effects has been confirmed.


title:
The $\alpha$-dependence of transition frequencies for ions Si II, Cr II,
  Fe II, Ni II, and Zn II

abstract:
  We performed accurate calculation of $\alpha$-dependence ($\alpha=e^2/hc$) of
the transition frequencies for ions, which are used in a search for the
variation of the fine structure constant $\alpha$ in space-time. We use
Dirac-Hartree-Fock method as a zero approximation and then the many-body
perturbation theory and configuration interaction methods to improve the
results. An important problem of level pseudocrossing (as functions of
$\alpha$) is considered. Near the crossing point the derivative of frequencies
over $\alpha$ varies strongly (including change of the sign). This makes it
very sensitive to the position of the crossing point. We proposed a
semiempirical solution of the problem which allows to obtain accurate results.


title: The Holistic Universe and the Variation of the Fine Structure Constant

abstract:
  Inaba recently used a simple model to suggest that Quantum Theory can result
from a fluctuation in the cosmos. In this note we confirm this conclusion from
a different and more general point of view. We then argue that this provides an
explanation for the recently observed variation of the fine structure constant.


title: Dynamics of nanojets

abstract:
  We study the breakup of a liquid jet a few nanometers in diameter, based on a
stochastic differential equation derived recently by Moseler and Landman
[Science {\bf 289}, 1165 (2000)]. In agreement with their simulations, we
confirm that noise qualitatively changes the characteristics of breakup,
leading to symmetric profiles. Using the path integral description, we find a
self-similar profile that describes the most probable breakup mode. As
illustrated by a simple physical argument, noise is the driving force behind
pinching, speeding up the breakup to make surface tension irrelevant.


title: K-calculus in 4-dimensional optics

abstract:
  4-dimensional optics is based on the use 4-dimensional movement space,
resulting from the consideration of the usual 3-dimensional coordinates
complemented by proper time. The paper uses the established K-calculus to make
a parallel derivation of special relativity and 4-dimensional optics, allowing
a real possibility of comparison between the two theories. The significance of
proper time coordinate is given special attention and its definition is made
very clear in terms of just send and receive instants of radar pulses. The
4-dimensional optics equivalent to relativistic Lorentz transformations is
reviewed.
  Special relativity and 4-dimensional optics are also compared in terms of
Lagrangian definition of worldlines and movement Hamiltonian. The final section
of the paper discusses simultaneity through the solution of a two particle
head-on collision problem. It is shown that a very simple graphical
construction automatically solves energy and momentum conservation when the
observer is located at the collision position. A further discussion of the
representation for a distant observer further clarifies how simultaneity is
accommodated by 4DO.


title: Dirac's fine-structure formula for an "abnormally high" nuclear charge

abstract:
  In Dirac's fine-structure formula for the hydrogenlike atoms a critical role
is played by the square root of the following expression: the unity minus the
square of the product of the atomic number by the fine-structure constant
(which is approximately equal to 1/137). Indeed, for a fictitious, ideal
nucleus for which the above product is greater than or equal to one, the
mentioned square root becomes imaginary, or zero. I prove in this Note that the
origin of such theoretical "breaking down" is quite simple and is inherent in
the special theory of relativity of classical physics.


title:
Comment on "Deuterium--tritium fusion reactors without external fusion
  breeding" by Eliezer et al

abstract:
  Inclusion of inverse Compton effects in the calculation of
deuterium-deuterium burn under the extreme conditions considered by Eliezer et
al. [Phys. Lett. A 243 (1998) 298] are shown to decrease the maximum burn
temperature from about 300 keV to only 100--150 keV. This decrease is such that
tritium breeding by the DD --> T + p reaction is not sufficient to replace the
small amount of tritium that is initially added to the deuterium plasma in
order to trigger ignition at less than 10 keV.


title: Coupled multi-component systems: A Simple Membrane Model

abstract:
  We present initial results regarding the existence, stability and interaction
of linear and nonlinear vibrational modes in a system of two coupled, one
dimensional lattices with unequal numbers of masses. The effects on these
nonlinear modes of coupling a near continuum system to a discrete system using
a nonlinear coupling are examined. This numerical model is a first step towards
investigating the dynamical behavior of a flexible sheet coupled nonlinearly to
a semi-rigid support, a system which could conceivably represent a biological
cell membrane with a supporting protein network. General implications for the
dynamical behavior of continuum systems coupled nonlinearly to discrete systems
are introduced.


title:
Signatures of Quantum-like Chaos in Dow Jones Index and Turbulent Fluid
  Flows

abstract:
  Dow Jones Index time series exhibit irregular or fractal fluctuations on all
time scales from days, months to years. The nonlinear fluctuations are
selfsimilar as exhibited in inverse power law form for power spectra of
temporal fluctuations. Inverse power law form for power spectra of fractal
fluctuations is generic to all dynamical systems in nature and is identified as
self-organized criticality.The author has developed a general systems theory
for universal quantification of the observed self-organized criticality in
dynamical systems. The model predicts that the power spectra of fractal
fluctuations follow the universal and unique inverse power law form of the
statistical normal distribution and is identified as a signature of
quantum-like chaos. Continuous periodogram power spectral analyses of
normalised daily, monthly and annual Dow Jones Index for the past 100-years
show that the power spectra follow the universal inverse power law form of the
statistical normal distribution in agreement with model prediction. Dow Jones
Index therefore exhibits self-organized criticality which is a signature of
quantum-like chaos on all time scales from days to years. All the data sets
exhibit periodicities close to model predicted values. The apparently noisy,
irregular fractal fluctuations of the Dow Jones Index contribute to the
formation of robust selfsimilar geometrical structures which indicate the
surprising resilience of market economy over a period of 100 years.


title:
Simulations of binary hard-sphere crystal-melt interfaces:Interface
  between a one- component fcc crystal and a binary fluid mixture

abstract:
  The crystal-melt interfaces of a binary hard-sphere fluid mixture in
coexistence with a single-component hard-sphere crystal is investigated using
molecular-dynamics simulation. In the system under study, the fluid phase
consists of a two-component mixture of hard spheres of differing size, with a
size ratio $\alpha=0.414$. At low pressures this fluid coexists with a pure fcc
crystal of the larger particles in which the small particles are immiscible.
For two interfacial orientations, [100] and [111], the structure and dynamics
within the interfacial region is studied and compared with previous simulations
on single component hard-sphere interfaces. Among a variety of novel
properties, it is observed that as the interface is traversed from fluid to
crystal the diffusion constant of the larger particle vanishes before that of
the small particle defining a region of the interface where the large particles
are frozen in their crystal lattice, but the small particles exhibit
significant mobility. This behavior was not seen in previous binary hard-sphere
interface simulations with less asymmetric diameters.


title:
Origin of anomalously long interatomic distances in suspended gold
  chains

abstract:
  The discovery of long bonds in gold atom chains has represented a challenge
for physical interpretation. In fact, interatomic distances frequently attain
3.0-3.6 A values and, distances as large as 5.0 A may be seldom observed. Here,
we studied gold chains by transmission electron microscopy and performed
theoretical calculations using cluster ab initio density functional formalism.
We show that the insertion of two carbon atoms is required to account for the
longest bonds, while distances above 3 A may be due to a mixture of clean and
one C atom contaminated bonds.


title:
High Sensitive Measurement of Absorption Coefficient and Optical
  Nonlinearities with a Single Experimental Setup

abstract:
  Accurate knowledge of absorption coefficient of a sample is a prerequisite
for measuring the third order optical nonlinearity of materials, which could
become a serious limitation for unknown samples. We introduce a new method,
which measures both the absorption coefficient and the third order optical
nonlinearity of materials with high sensitivity in a single experimental setup.
We use a dual-beam pump-probe experiment under different conditions to achieve
this goal. We also demonstrate a counterintuitive coupling of the
non-interacting probe-beam with the pump-beam in pump-probe z-scan experiment.


title:
The Parity Non-Conserving 3P0--1P1 E1 Transition Amplitude of the Atomic
  Yb

abstract:
  The atomic parity non-conservation(PNC) experiments has reached accuracies
which have important implications for physics beyond the standard model. An
optical rotation experiment to measure the atomic PNC of the
3P1(6s6p)--1P1(6s6p) in Yb was proposed recently. Our screened
electron-electron coulomb potential multi-configuration Dirac-Fock calculation
of th PNC induced E1 transition amplitude of this transition E1_PNC = -96.0 x
10^{-11}iea_0(-Q_W/N) of 171Yb is more than two orders of magnitude larger than
E1_PNC(6s-7s) = -0.8991 x 10^{-11}iea_0(-Q_W/N) of 133Cs.


title:
Diamagnetic Interactions in Disordered Suspensions of Metastable
  Superconducting Granules

abstract:
  The simulation of the transition sequence of superheated Type I
superconducting granules (SSG) in disordered suspensions when an external
magnetic field is slowly increased from zero has been studied. Simulation takes
into account diamagnetic interactions and the presence of surface defects.
Results have been obtained for the transition sequence and surface fields
distribution covering a wide range of densities. These results are compared
with previous analytical perturbative theory, which provides qualitative
information on transitions and surface magnetic fields during transitions, but
with a range of validity apparently limited to extremely dilute samples.
Simulations taking into account the complete diamagnetic interactions between
spheres appear to be a promising tool in interpreting SSG experiments, in
applications such as particle detectors, and in some fundamental calculations
of Solid State Physics.


title: What is research?

abstract:
  Doing research is fighting, what any other thing the human being could do?
Fight against powers or to get powers, that depends on us. Science can be a
revolution or deadlocked idleness. Still waters, without hitting the stones
along their history, trend to form bogs.


title:
Measurement of Superluminal optical tunneling times in double-barrier
  photonic bandgaps

abstract:
  Tunneling of optical pulses at 1.5 micron wavelength through double-barrier
periodic fiber Bragg gratings is experimentally investigated. Tunneling time
measurements as a function of barrier distance show that, far from the
resonances of the structure, the transit time is paradoxically short, implying
Superluminal propagation, and almost independent of the distance between the
barriers. These results are in agreement with theoretical predictions based on
phase time analysis and also provide an experimental evidence, in the optical
context, of the analogous phenomenon expected in Quantum Mechanics for
non-resonant superluminal tunneling of particles across two successive
potential barriers. [Attention is called, in particular, to our last Figure].
PACS nos.: 42.50.Wm, 03.65.Xp, 42.70.Qs, 03.50.De, 03.65.-w, 73.40.Gk


title: Status Report of the Inter-Laboratory Task Force on Remote Operation

abstract:
  In February 2000, the International Committee for Future Accelerators
initiated a study of a new model for international collaboration on a future
large accelerator project, the Global Accelerator Network. The study is based
on a model of a facility, which is remote from most of the collaborating
institutions. It is designed, built and operated by a collaboration of equal
partner institutions distributed around the world. According to this model, the
expert-staff from each laboratory remains based at their home institution but
continues to participate in the operation of the machine after construction.
This report summarizes the conclusions of the Task Force on Remote Operation,
which investigated the general and technical implications of far-remote
operations.


title: Electric microfield distributions in electron-ion plasmas

abstract:
  The low-frequency electric microfield distribution in a Coulomb plasma is
calculated for various plasma parameters, from weak to strong Coulomb coupling
and from zero to strong electron screening. Two methods of numerical
calculations are employed: the adjustable-parameter exponential approximation
and the Monte Carlo simulation. The results are represented by analytic fitting
formulas suitable for applications.


title:
Entropic Priors for Discrete Probabilistic Networks and for Mixtures of
  Gaussians Models

abstract:
  The ongoing unprecedented exponential explosion of available computing power,
has radically transformed the methods of statistical inference. What used to be
a small minority of statisticians advocating for the use of priors and a strict
adherence to bayes theorem, it is now becoming the norm across disciplines. The
evolutionary direction is now clear. The trend is towards more realistic,
flexible and complex likelihoods characterized by an ever increasing number of
parameters. This makes the old question of: What should the prior be? to
acquire a new central importance in the modern bayesian theory of inference.
Entropic priors provide one answer to the problem of prior selection. The
general definition of an entropic prior has existed since 1988, but it was not
until 1998 that it was found that they provide a new notion of complete
ignorance. This paper re-introduces the family of entropic priors as minimizers
of mutual information between the data and the parameters, as in
[rodriguez98b], but with a small change and a correction. The general formalism
is then applied to two large classes of models: Discrete probabilistic networks
and univariate finite mixtures of gaussians. It is also shown how to perform
inference by efficiently sampling the corresponding posterior distributions.


title:
$\lambda /4$, $\lambda /8$, and higher order atom gratings via Raman
  transitions

abstract:
  A method is proposed for producing atom gratings having period $\lambda /4$
and $\lambda /8$ using optical fields having wavelength $\lambda $.
Counterpropagating optical fields drive Raman transitions between ground state
sublevels. The Raman fields can be described by an effective two photon field
having wave vector 2 k, where k is the propagation vector of one of the fields.
By combining this Raman field with {\em another} Raman field having propagation
vector -2 k, one, in effect, creates a standing wave Raman field
\label{91}%which whose ``intensity'' varies as $\cos (4 k\cdot r).$ When atoms
move through this standing wave field, atom gratings having period $\lambda /4$
are produced, with the added possibility that the total ground state population
in a given ground state manifold can have $\lambda /8$ periodicity. The
conditions required to produce such gratings are derived. Moreover, it is shown
that even higher order gratings having periodicity smaller than $\lambda /8$
can be produced using a multicolor field geometry involving three (two-photon)
Raman fields. Although most calculations are carried out in the Raman-Nath
approximation, the use of Raman fields to create reduced period optical
lattices is also discussed.


title: Quantization of energy and writhe in self-repelling knots

abstract:
  Probably the most natural energy functional to be considered for knotted
strings is the one given by the electrostatic repulsion. In the absence of
counter-charges, a charged, knotted string evolving along the energy gradient
of electrostatic repulsion would progressively tighten its knotted domain into
a point on a perfectly circular string. However, in the presence of charge
screeningthe self-repelling knotted strings can get stabilised. It is known
that energy functionals in which repulsive forces between repelling charges
grow inversely proportional to the third or higher power of their relative
distance stabilise self-repelling knots. Especially interesting is the case of
the third power since the repulsive energy becomes scale invariant and does not
change upon Moebius transformations (reflections in spheres) of knotted
trajectories. We observe here thatknots minimising their repulsive Moebius
energy show quantization of the energy and writhe (measure of chirality) within
several tested families of knots.


title: The polymer mat: Arrested rebound of a compressed polymer layer

abstract:
  Compression of an adsorbed polymer layer distorts its relaxed structure.
Surface force measurements from different laboratories show that the return to
this relaxed structure after the compression is released can be slowed to the
scale of tens of minutes and that the recovery time grows rapidly with
molecular weight. We argue that the arrested state of the free layer before
relaxation can be described as a Guiselin brush structure1, in which the
surface excess lies at heights of the order of the layer thickness, unlike an
adsorbed layer. This brush structure predicts an exponential falloff of the
force at large distance with a decay length that varies as the initial
compression distance to the 6/5 power. This exponential falloff is consistent
with surface force measurements. We propose a relaxation mechanism that
accounts for the increase in relaxation time with chain length.


title: Dissociation of Diatomic Molecule by Energy-Feedback Control

abstract:
  New method for dissociation of diatomic molecule based on nonperiodic
excitation generated by energy-feedback control mechanism is proposed. The
energy-feedback control uses frequency-energy (FE) relation of the natural
oscillations to fulfill the resonance conditions at any time of excitation.
  Efficiency of the proposed method is demonstrated by the problem of
dissociation of hydrogen fluoride (HF) molecule. It is shown that new method is
more efficient then methods based on constant frequency and linear chirping
excitation.


title:
Self-consistent model of ultracold atomic collisions and Feshbach
  resonances in tight harmonic traps

abstract:
  We consider the problem of cold atomic collisions in tight traps, where the
absolute scattering length may be larger than the trap size. As long as the
size of the trap ground state is larger than a characteristic length of the van
der Waals potential, the energy eigenvalues can be computed self-consistently
from the scattering amplitude for untrapped atoms. By comparing with the exact
numerical eigenvalues of the trapping plus interatomic potentials, we verify
that our model gives accurate eigenvalues up to milliKelvin energies for single
channel s-wave scattering of $^{23}$Na atoms in an isotropic harmonic trap,
even when outside the Wigner threshold regime. Our model works also for
multi-channel scattering, where the scattering length can be made large due to
a magnetically tunable Feshbach resonance.


title: Macrodimers: ultralong range Rydberg molecules

abstract:
  We study long range interactions between two Rydberg atoms and predict the
existence of ultralong range Rydberg dimers with equilibrium distances of many
thousand Bohr radii. We calculate the dispersion coefficients $C_{5}$, $C_{6}$
and $C_{8}$ for two rubidium atoms in the same excited level $np$, and find
that they scale like $n^{8}$, $n^{11}$ and $n^{15}$, respectively. We show that
for certain molecular symmetries, these coefficients lead to long range
potential wells that can support molecular bound levels. Such macrodimers would
be very sensitive to their environment, and could probe weak interactions. We
suggest experiments to detect these macrodimers.


title: Remarks on the correspondence of the relativity and causality principles

abstract:
  A particular problem about special kind of two light pulses propagation has
been considered in cases of inertial motion, constant homogeneous gravitation
field and progressive non-inertial motion with constant acceleration. A
contradiction between the causality principle and relativity theory has been
revealed.


title: Self interaction near dielectrics

abstract:
  We compute the force acting on a free, static electric charge outside a
uniform dielectric sphere. We view this force as a self-interaction force, and
compute it by applying the Lorentz force directly to the charge's electric
field at its location. We regularize the divergent bare force using two
different methods: A direct application of the Quinn-Wald Comparison Axiom, and
Mode-Sum Regularization.


title: Nonlinear magneto-optical rotation with frequency-modulated light

abstract:
  A magnetometric technique is demonstrated that may be suitable for precision
measurements of fields ranging from the sub-microgauss level to above the Earth
field. It is based on resonant nonlinear magneto-optical rotation caused by
atoms contained in a vapor cell with anti-relaxation wall coating. Linearly
polarized, frequency-modulated laser light is used for optical pumping and
probing. If the time-dependent optical rotation is measured at the first
harmonic of the modulation frequency, ultra-narrow (~a few Hz) resonances are
observed at near-zero magnetic fields, and at fields where the Larmor frequency
coincides with half the light modulation frequency. Upon optimization, the
sensitivity of the technique is expected to exceed 10^{-11} G/sqrt{Hz}.


title:
Experimental determination of the $6s^2 ^1S_0 -> 5d6s ^3 D_1$
  magnetic-dipole transition amplitude in atomic ytterbium

abstract:
  We report on a measurement of the highly forbidden $6s^2 ^1S_0 \to 5d6s ^3
D_1$ magnetic-dipole transition in atomic ytterbium using the
Stark-interference technique. This amplitude is important in interpreting a
future parity nonconservation experiment that exploits the same transition. We
find $| < 5d6s ^3 D_1 | M1 | 6s^2 ^1S_0 > | ~ = ~ 1.33(6)_{Stat}(20)_{\beta}
\times 10^{-4} \mu_0$, where the larger uncertainty comes from the previously
measured vector transition polarizability $\beta$. The $M1$ amplitude is small
and should not limit the precision of the parity nonconservation experiment.


title:
Spike timing and the coding of naturalistic sounds in a central auditory
  area of songbirds

abstract:
  In nature, animals encounter high dimensional sensory stimuli that have
complex statistical and dynamical structure. Attempts to study the neural
coding of these natural signals face challenges both in the selection of the
signal ensemble and in the analysis of the resulting neural responses. For
zebra finches, naturalistic stimuli can be defined as sounds that they
encounter in a colony of conspecific birds. We assembled an ensemble of these
sounds by recording groups of 10-40 zebra finches, and then analyzed the
response of single neurons in the songbird central auditory area (field L) to
continuous playback of long segments from this ensemble.
  Following methods developed in the fly visual system, we measured the
information that spike trains provide about the acoustic stimulus without any
assumptions about which features of the stimulus are relevant. Preliminary
results indicate that large amounts of information are carried by spike timing,
with roughly half of the information accessible only at time resolutions better
than 10 ms; additional information is still being revealed as time resolution
is improved to 2 ms. Information can be decomposed into that carried by the
locking of individual spikes to the stimulus (or modulations of spike rate) vs.
that carried by timing in spike patterns. Initial results show that in field L,
temporal patterns give at least ~20% extra information. Thus, single central
auditory neurons can provide an informative representation of naturalistic
sounds, in which spike timing may play a significant role.


title:
Chance and Necessity in Fermi's Discovery of the Properties of the Slow
  Neutrons

abstract:
  In October 1934 Fermi discovered that neutrons became particularly effective
in rendering the elements radioactive after being slowed down by hydrogenous
substances. His was described as an absolutely unpredictable scientific
discovery. In this paper I report and discuss the knowledge about neutrons
properties already available the previous year, which throws a new light onto a
discovery too often depicted as "accidental".


title:
Gain without population inversion in V-type systems driven by a
  frequency-modulated field

abstract:
  We obtain gain of the probe field at multiple frequencies in a closed
three-level V-type system using frequency modulated pump field. There is no
associated population inversion among the atomic states of the probe
transition. We describe both the steady-state and transient dynamics of this
system. Under suitable conditions, the system exhibits large gain
simultaneously at series of frequencies far removed from resonance. Moreover,
the system can be tailored to exhibit multiple frequency regimes where the
probe experiences anomalous dispersion accompanied by negligible
gain-absorption over a large bandwidth, a desirable feature for obtaining
superluminal propagation of pulses with negligible distortion.


title:
"Wild Cables" in Fusion Plasmas and their Diagnostics with Spectral Line
  Stark Broadening

abstract:
  We discuss the opportunities of diagnosing the parameters of hypothetical
"wild cables" in fusion plasmas via analyzing the Stark broadening of hydrogen
spectral lines. The "wild cables" concept have suggested the observed
long-lived skeletal structures in tokamaks and Z-pinches to be caused by a
microdust-assembled skeleton. We present the results of calculating the widths
of vacuum channels produced by the pressure of on-skeleton high-frequency (HF)
electromagnetic waves of the TEM type, which thus might protect the skeletons
from ambient high-temperature plasma. The values of amplitude of such wave
appear to be compatible with the measurements of those in-plasma HF electric
fields in tokamak T-10 and a gaseous Z-pinch which give observable Stark
broadening of hydrogen spectral lines.


title: Orbiting Resonances and Bound States in Molecular Scattering

abstract:
  A family of orbiting resonances in molecular scattering is globally described
by using a single pole moving in the complex angular momentum plane. The
extrapolation of this pole at negative energies gives the location of the bound
states. Then a single pole trajectory, that connects a rotational band of bound
states and orbiting resonances, is obtained. These complex angular momentum
singularities are derived through a geometrical theory of the orbiting. The
downward crossing of the phase-shifts through pi/2, due to the repulsive region
of the molecular potential, is estimated by using a simple hard-core model.
Some remarks about the difference between diffracted rays and orbiting are also
given.


title:
Solar Activity and Cloud Opacity Variations: A Modulated Cosmic-Ray
  Ionization Model

abstract:
  The observed correlation between global low cloud amount and the flux of high
energy cosmic rays supports the idea that ionization plays a crucial role in
tropospheric cloud formation. We explore this idea quantitatively with a simple
model linking the concentration of cloud condensation nuclei to the varying
ionization rate due to cosmic rays. Among the predictions of the model is a
variation in global cloud optical thickness, or opacity, with cosmic-ray rate.
Using the International Satellite Cloud Climatology Project database
(1983-1999), we search for variations in the yearly mean visible cloud opacity
and visible cloud amount due to cosmic rays. After separating out temporal
variations in the data due to the Mt. Pinatubo eruption and El Nino/Southern
Oscillation, we identify systematic variations in opacity and cloud amount due
to cosmic rays. We find that the fractional amplitude of the opacity variations
due to cosmic rays increases with cloud altitude, becoming approximately zero
or negative (inverse correlation) for low clouds. Conversely, the fractional
changes in visible cloud amount due to cosmic rays are only
positively-correlated for low clouds and become negative or zero for the higher
clouds. The opacity trends suggest behavior contrary to the current predictions
of ion-mediated nucleation (IMN) models, but more accurate temporal modeling of
the ISCCP data is needed before definitive conclusions can be drawn.


title:
Finding regulatory sites from statistical analysis of nucleotide
  frequencies in the upstream region of eukaryotic genes

abstract:
  We discuss two new approaches to extract relevant biological information on
the Transcription Factors (and in particular to identify their binding
sequences) from the statistical distribution of oligonucleotides in the
upstream region of the genes. Both the methods are based on the notion of a
``regulatory network'' responsible for the various expression patterns of the
genes. In particular we concentrate on families of coregulated genes and look
for the simultaneous presence in the upstream regions of these genes of the
same set of transcription factor binding sites. We discuss two instances which
well exemplify the features of the two methods: the coregulation of glycolysis
in Drosophila melanogaster and the diauxic shift in Saccharomyces cerevisiae.


title: An Intense Source of Cold Rb Atoms from a Pure 2D-MOT

abstract:
  We present a 2D-MOT setup for the production of a continuous collimated beam
of cold 87-Rb atoms out of a vapor cell. The underlying physics is purely
two-dimensional cooling and trapping, which allows for a high flux of up to
6*10^(10) atoms/s and a small divergence of the resulting beam. We analyze the
velocity distribution of the 2D-MOT. The longitudinal velocity distribution of
the atomic beam shows a broad feature(FWHM=75m/s), centered around 50m/s. The
dependence of the flux on laser intensity, geometry of the trapping volume and
on pressure in the vapor cell was investigated in detail. The influence of the
geometry of the 2D-MOT on the mean velocity of the cold beam has been studied.
We present a simple model for the velocity distribution of the flux based on
rate equations describing the general dependencies.


title: Microscopic Calculation of the Constitutive Relations

abstract:
  Homogenization theory is used to calculate the macroscopic dielectric
constant from the quantum microscopic dielectric function in a periodic medium.
The method can be used to calculate any macroscopic constitutive relation, but
it is illustrated here for the case of electrodynamics of matter. The so-called
cell problem of homogenization theory is solved and an explicit expression is
given for the macroscopic dielectric constant in a form akin to the
Clausius-Mossotti or Lorentz-Lorenz relation. The validity of this expression
is checked by showing that the macroscopic dielectric constant is causal and
has the expected symmetry properties, and that the average of the microscopic
energy density is the macroscopic one. Finally, the general expression is
applied to Bloch eigenstates. Finally, the corresponding many-body problem is
briefly discussed.


title: Scaling at the selective withdrawal transition

abstract:
  In the selective withdrawal experiment fluid is withdrawn through a tube with
its tip suspended a distance S above an unperturbed two-fluid interface. At low
withdrawal rates, Q, the interface forms a steady state hump and only the upper
fluid is withdrawn. When Q is increased (or S decreased), the interface
undergoes a transition so that the lower fluid is entrained with the upper one,
forming a thin steady-state spout. Near this discontinuous transition the hump
curvature becomes very large and displays power-law scaling behavior. This
scaling is used to show that steady-state profiles for humps at different flow
rates and tube heights can all be scaled onto a single similarity profile.


title:
Scaling dependence on the fluid viscosity ratio in the selective
  withdrawal transition

abstract:
  In the selective withdrawal experiment fluid is withdrawn through a tube with
its tip suspended a distance S above a two-fluid interface. At sufficiently low
withdrawal rates, Q, the interface forms a steady state hump and only the upper
fluid is withdrawn. When Q is increased (or S decreased), the interface
undergoes a transition so that the lower fluid is entrained with the upper one,
forming a thin steady-state spout. Near this transition the hump curvature
becomes very large and displays power-law scaling behavior. This scaling allows
for steady-state hump profiles at different flow rates and tube heights to be
scaled onto a single similarity profile. I show that the scaling behavior is
independent of the viscosity ratio.


title:
Voltage-controlled wavelength conversion by terahertz electro-optic
  modulation in double quantum wells

abstract:
  An undoped double quantum well (DQW) was driven with a terahertz (THz)
electric field of frequency \omega_{THz} polarized in the growth direction,
while simultaneously illuminated with a near-infrared (NIR) laser at frequency
\omega_{NIR}. The intensity of NIR upconverted sidebands
\omega_{sideband}=\omega_{NIR} + \omega_{THz} was maximized when a dc voltage
applied in the growth direction tuned the excitonic states into resonance with
both the THz and NIR fields. There was no detectable upconversion far from
resonance. The results demonstrate the possibility of using gated DQW devices
for all-optical wavelength shifting between optical communication channels
separated by up to a few THz.


title: Time-Varying Fine-Structure Constant and Quantum SuperStrings

abstract:
  In this note we observe that Webb and co-workers' observation of an evolving
fine structure constant has since been reconfirmed. We also confirm Kuhne's
contention that this implies a cosmological constant and exhibit a cosmological
mechanism for Webb's result. We also see how this provides a mechanism to reach
elementary particle scales from the Quantum Superstring scale.


title: On a naive construction of kinetic equation

abstract:
  We return to the subject of stability of infinite time asymptotics of kinetic
equations. We found a model which is simpler than those studied previously and
which shows unstable behavior corresponding to our arguments to appear
elsewhere, where, however, a relatively complicated problem was treated. Our
simplification to four levels interacting with surroundings enable us to
proceed easily through all the way with just a pen and paper. We provide no
numerical modelling whose justification causes naturally difficulties to the
reader. We draw also further consequences of the found instability, not only
with respect to higher order terms in kinetic equations but also concerning the
very philosophy of physical modelling. The latter point can give more
practically oriented physicist even better motivation than mere speculations
about potential instabilities due to higher order terms in perturbation
treatments without concrete resolution of correct asymptotics.


title: Resonant Laser Cooling of Relativistic Charges Beams

abstract:
  In work is considered average transverse dynamics of an electron beam in the
autoresonant laser. It is shown, that in approach of the given external
electromagnetic wave (small gain free electron laser) transverse emittance of a
beam of the charged particles decreases. This for the first time found out
effect can be used for cooling beams of various accelerators of the charged
particles. In the field of particle energy about 100 in the mass energy units,
beam energy losses are negligible. This method of charge beams cooling may be
applied to electron, muon and various heavy particle beams.


title:
Relativistic Causality and Conservation of Energy in Classical
  Electromagnetic Theory

abstract:
  The change of the electromagnetic field in a particular place due to the
event of a change in the motion of a charged particle can occur only after the
light signal from the event can reach this place. Naive calculations of the
electromagnetic energy and the work performed by the electromagnetic fields
might lead to paradoxes of apparent non-conservation of energy. A few paradoxes
of this type for a simple motion of two charges are presented and resolved in a
quantitative way providing deeper insight into various relativistic effects in
the classical electromagnetic theory.


title:
How Is Nature Asymmetric ? 1. Discrete Symmetries in Particle Physics
  and Parity Violation

abstract:
  This two-part article considers certain fundamental symmetries of nature,
namely the discrete symmetries of parity (P), charge conjugation (C) and time
reversal (T), and their possible violation. Recent experimental results are
discussed in some depth. In the first part of this article we present a general
background and discuss parity violation.


title:
How Is Nature Asymmetric 2 CP and T Violation in Elementary Particle
  Physics

abstract:
  This two-part article considers certain fundamental symmetries of nature,
namely the discrete symmetries of parity (P), charge conjugation (C) and time
reversal (T), and their possible violation. Recent experimental results are
discussed in some depth. In this second part, we discussion CP and $T$
violation and arrive at a synthesis.


title:
Phenomenological model of propagation of the elastic waves in a
  fluid-saturated porous solid with non-zero boundary slip velocity

abstract:
  Zhu & Granick [Phys. Rev. Lett. 87, 096105 (2001)] have recently
experimentally established existence of a boundary slip in a Newtonian liquid.
They reported typical values of the slip length of the order of few
micro-meters. In this light, the effect of introduction of the boundary slip
into the theory of propagation of elastic waves in a fluid-saturated porous
medium formulated by Biot is investigated. The new model should allow to fit
the experimental seismic data in circumstances when Biot's theory fails, as the
introduction of phenomenological dependence of the slip velocity upon
frequency, which is based on robust physical arguments, adds an additional
degree of freedom to the model. If fact, it predicts higher than the Biot's
theory values of attenuation coefficients of the both rotational and
dilatational waves in the intermediate frequency domain, which is in
qualitative agreement with the experimental data. Therefore, the introduction
of the boundary slip yields three-fold benefits: (A) Better agreement of theory
with an experimental data since the parametric space of the model is larger
(includes effects of boundary slip); (B) Possibility to identify types of
porous medium and physical situations where boundary slip is important; (C)
Constrain model parameters that are related to the boundary slip.


title: Theory of Systematic Computational Error in Free Energy Differences

abstract:
  Systematic inaccuracy is inherent in any computational estimate of a
non-linear average, due to the availability of only a finite number of data
values, N. Free energy differences (DF) between two states or systems are
critically important examples of such averages in physical, chemical and
biological settings. Previous work has demonstrated, empirically, that the
``finite-sampling error'' can be very large -- many times kT -- in DF estimates
for simple molecular systems. Here, we present a theoretical description of the
inaccuracy, including the exact solution of a sample problem, the precise
asymptotic behavior in terms of 1/N for large N, the identification of
universal law, and numerical illustrations. The theory relies on corrections to
the central and other limit theorems, and thus a role is played by stable
(Levy) probability distributions.


title: Ionospheric response to the total solar eclipse of June 21, 2001

abstract:
  We discuss the measurements of the main parameters of the ionospheric
response to the total solar eclipse of June 21, 2001. This study is based on
using the data from three stations of the global GPS network located in the
area of the totality band in Africa. This period was characterized by a low
level of geomagnetic disturbance (the Dst-index varied from -6 to 22 nT), which
alleviated greatly the problem of detecting the ionospheric response to
eclipse. An analysis revealed a clearly pronounced effect of a decrease
(depression) of the total electron content (TEC) for all GPS stations. The
delay between the smallest value of the TEC with respect to eclipse totality
was 9-37 min. The depth and duration of the TEC depression were 0.5-0.9 TECU
and 30-67 min, respectively. The results obtained in this study are in good
agreement with earlier measurements and theoretical estimations.


title: AIDA: Accelerator Integrated Data Access

abstract:
  All Control Systems that grow to any size have a variety of data that are
stored in different formats on different nodes in the network. Examples include
sensor value and status, archived sensor data, device oriented support data and
relationships, message logs, application and machine configurations etc. Each
type of data typically has a different programming interface. Higher-level
applications need to access a logically related set of data that is in
different data stores and may require different processing. AIDA is envisioned
to be a distributed service that allows applications access to this wide
variety of Control System data in a consistent way that is language and machine
independent. It has the additional goal of providing an object-oriented layer
for constructing applications on top of multiple existing conventional systems
like EPICS or the SLC Control System. Motivation, design overview and current
status will be presented.


title:
Energy Resolution Improvement of Scintielectron detectors: Priorities
  and Prospects

abstract:
  The development prospects of a scintillator-photodiode type detector with an
improved energy resolution attaining few per cent, R from 1 to 2%, are
considered. The main resolution components have been analyzed theoretically,
their theoretical and physical limits have been established. Empirical data on
the properties of novel scintillators have been presented confirming the
possibility of the R improvement. New optimization methods have been proposed
to optimize the detector statistical fluctuations and the scintillator
intrinsic resolution. A specific importance of the intrinsic resolution is
shown as a limiting threshold factor at the ionizing radiation energy values
from 662 keV to 10 MeV and over.


title: Precision Optical Measurements and Fundamental Physical Constants

abstract:
  A brief overview is given on precision determinations of values of the
fundamental physical constants and the search for their variation with time by
means of precision spectroscopy in the optical domain.


title: A Classical Probabilistic Computer Model of Consciousness

abstract:
  We show that human consciousness can be modeled as a classical (not quantum)
probabilistic computer. A quantum computer representation does not appear to be
indicated because no known feature of consciousness depends on Planck's
constant h, the telltale sign of quantum phenomena. It is argued that the
facets of consciousness are describable by an object-oriented design with
dynamically defined classes and objects. A comparison to economic theory is
also made. We argue consciousness may also have redundant, protective
mechanisms.

categories: physics.bio-ph cond-mat.dis-nn physics.med-ph physics.pop-ph


title:
Analytical Potential Energy Function for the Ground State X^{1} Sigma^+
  of LaCl

abstract:
  The equilibrium geometry, harmonic frequency and dissociation energy of
lanthanum monochloride have been calculated at B3LYP, MP2, QCISD(T) levels with
energy-consistent relativistic effective core potentials. The possible
electronic state and reasonable dissociation limit for the ground state are
determined based on atomic and molecular reaction statics. Potential energy
curve scans for the ground state X^{1} Sigma^+ have been carried out with B3LYP
and QCISD(T) methods due to their better performance in bond energy
calculations. We find the potential energy calculated with QCISD(T) method is
about 0.5 eV larger than dissociation energy when the diatomic distance is as
large as 0.8 nm. The problem that single-reference ab initio methods don't meet
dissociation limit during calculations of lanthanide heavy-metal elements is
analyzed. We propose the calculation scheme to derive analytical Murrell-Sorbie
potential energy function and Dunham expansion at equilibrium position.
Spectroscopic constants got by standard Dunham treatment are in good agreement
with results of rotational analyses on spectroscopic experiments. The
analytical function is of much realistic importance since it is possible to be
applied to predict fine transitional structure and study reaction dynamic
process.


title: Speed of light measurement using ping

abstract:
  We report on a very simple and inexpensive method for determining the speed
of an electrical wave in a transmission line. The method consists of analyzing
the roundtrip time for ethernet packets between two computers. It involves
minimal construction, straightforward mathematics and displays the usefulness
of stochastic resonance in signal recovery. Using basic electrical properties
of category-five cable students may use their measurements to determine the
speed of light in the vacuum to within a few percent.


title: Global Optimization by Energy Landscape Paving

abstract:
  We introduce a novel heuristic global optimization method, energy landscape
paving (ELP), which combines core ideas from energy surface deformation and
tabu search. In appropriate limits, ELP reduces to existing techniques. The
approach is very general and flexible and is illustrated here on two protein
folding problems. For these examples, the technique gives faster convergence to
the global minimum than previous approaches.


title: Complexity: An Introduction

abstract:
  This article summarises a Web-book on "Complexity" that was developed to
introduce undergraduate students to interesting complex systems in the
biological, physical and social sciences, and the common tools, principles and
concepts used for their study.

categories: physics.ed-ph physics.comp-ph physics.pop-ph physics.soc-ph


title: Short popular review of quantum electromagnetodynamics

abstract:
  The aim of this note is to give a short and popular review of the ideas which
led to my model of magnetic monopoles (hep-ph/9708394) and my prediction of the
second kind of electromagnetic radiation. I will also point out the many and
far-reaching consequences if these magnetic photon rays would be confirmed.


title: Quantization of Masses in the Solar System

abstract:
  The hypothesis of quantization of masses of the solar system planets is
considered. It is supposed that the solar system was bearing during the
Protosun squeezing from the red giant to a yellow dwarf. According to mass and
orbit redistribution of interior planets the condition of the origin of
satellites of internal and external planets located in the ecliptic plane are
found. It is shown, that the main source of substance for these satellites and
majority of meteorites and asteroids in the solar system is mantle and bark of
the Mars separated from it under influence of gravitation forces about 4
billion years ago, caused by squeezing of the sun and Jupiter. In these
condition there is a probability of contamination of the Earth by DNA of living
organisms from Mars. It is shown that Uranus and Neptune were formed as a
result of protosaturn decay. It is found that from all external planets only
Uranus has the large cavity inside. As a result there is no internal power
source, and the considerable shift of a magnetic axis relative to rotate axis
is observed.


title: The Gravitational Mass at the Superconducting State

abstract:
  It will be shown that the gravitational masses of the electrons of a
superconducting material are strongly negative. Particularly, for an amount of
mercury (Hg) at the transition temperature, Tc = 4.15 K, the negative
gravitational masses of the electrons decrease the total gravitational mass of
the Hg of approximately 0.1 percent. The weight reduction increase when the Hg
is spinning inside a magnetic field or when it is placed into a strong
oscillating EM field.


title: Thermodynamics of a classical ideal gas at arbitrary temperatures

abstract:
  We propose a fundamental relation for a classical ideal gas that is valid at
all temperatures with remarkable accuracy. All thermodynamical properties of
classical ideal gases can be deduced from this relation at arbitrary
temperature.


title:
Ga-rich GaAs(001) surfaces observed during high-temperature annealing by
  scanning tunneling microscopy

abstract:
  Ga-rich GaAs (001) surfaces are successfully observed during high-temperature
annealing by scanning tunneling microscopy (STM). With a substrate temperature
of 550 C, reflection high-energy diffraction patterns and reflectance
anisotropy spectra confirm a (4x2) Ga-stabilized surface. STM images clearly
show alteration of the surface reconstructions while scanning. It is postulated
that detaching and attaching of Ga adatoms may be the cause of these surface
dynamics. For these conditions it is determined that zeta(4x4), zeta2(4x4) and
zeta(4x6) reconstructions co-exist on the surface. The zeta2(4x4)
reconstruction contains a Ga tetramer cluster and in more Ga-rich conditions,
the zeta2(4x6) surface has a Ga octamer cluster.


title: Nonlinear analysis of bivariate data with cross recurrence plots

abstract:
  We use the extension of the method of recurrence plots to cross recurrence
plots (CRP) which enables a nonlinear analysis of bivariate data. To quantify
CRPs, we develop further three measures of complexity mainly basing on diagonal
structures in CRPs. The CRP analysis of prototypical model systems with
nonlinear interactions demonstrates that this technique enables to find these
nonlinear interrelations from bivariate time series, whereas linear correlation
tests do not. Applying the CRP analysis to climatological data, we find a
complex relationship between rainfall and El Nino data.

categories: physics.data-an math-ph math.MP nlin.CD physics.geo-ph


title: Cross Recurrence Plot Based Synchronization of Time Series

abstract:
  The method of recurrence plots is extended to the cross recurrence plots
(CRP), which among others enables the study of synchronization or time
differences in two time series. This is emphasized in a distorted main diagonal
in the cross recurrence plot, the line of synchronization (LOS). A
non-parametrical fit of this LOS can be used to rescale the time axis of the
two data series (whereby one of it is e.g. compressed or stretched) so that
they are synchronized. An application of this method to geophysical sediment
core data illustrates its suitability for real data. The rock magnetic data of
two different sediment cores from the Makarov Basin can be adjusted to each
other by using this method, so that they are comparable.


title: Helium in superstrong magnetic fields

abstract:
  We investigate the helium atom embedded in a superstrong magnetic field
gamma=100-10000 au. All effects due to the finite nuclear mass for vanishing
pseudomomentum are taken into account. The influence and the magnitude of the
different finite mass effects are analyzed and discussed. Within our full
configuration interaction approach calculations are performed for the magnetic
quantum numbers M=0,-1,-2,-3, singlet and triplet states, as well as positive
and negative z parities. Up to six excited states for each symmetry are
studied. With increasing field strength the number of bound states decreases
rapidly and we remain with a comparatively small number of bound states for
gamma=10^4 au within the symmetries investigated here.


title:
Recurrence Plot Based Measures of Complexity and its Application to
  Heart Rate Variability Data

abstract:
  The knowledge of transitions between regular, laminar or chaotic behavior is
essential to understand the underlying mechanisms behind complex systems. While
several linear approaches are often insufficient to describe such processes,
there are several nonlinear methods which however require rather long time
observations. To overcome these difficulties, we propose measures of complexity
based on vertical structures in recurrence plots and apply them to the logistic
map as well as to heart rate variability data. For the logistic map these
measures enable us not only to detect transitions between chaotic and periodic
states, but also to identify laminar states, i.e. chaos-chaos transitions. The
traditional recurrence quantification analysis fails to detect the latter
transitions. Applying our new measures to the heart rate variability data, we
are able to detect and quantify the laminar phases before a life-threatening
cardiac arrhythmia occurs thereby facilitating a prediction of such an event.
Our findings could be of importance for the therapy of malignant cardiac
arrhythmias.

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


title: Associative delusions and problem of their overcoming

abstract:
  Influence of associative delusions (AD) onto development of physics and
mathematics is investigated. The associative delusion (AD) means a mistake,
appearing from incorrect associations, when a property of one object is
attributed to another one. Examples of most ancient delusions are: (1)
connection of the gravitation field direction with a preferred direction in
space (instead of the direction towards the Earth centre), that had lead to the
antipode paradox, (2) statement that the Earth (not the Sun) is the centre of
the planetary system, that had lead to the Ptolemaic doctrine. Now these ADs
have been overcame. In the paper one considers four modern and not yet got over
ADs, whose corollaries are false space-time geometry in the micro world and
most of problems and difficulties of the quantum field theory (QFT). One shows
that ADs have a series of interesting properties: (1) ADs appear to be
long-living delusions, because they are compensated partly by means of
introduction of compensating (Ptolemaic) conceptions, (2) ADs influence on
scientific investigations, generating a special pragmatic style (P-style) of
investigations resembling experimental trial and error method, (3) acting on
investigations directly and via P-style, ADs direct the science development
into a blind alley. One considers concrete properties of modern ADs and the
methods of their overcoming. From viewpoint of application the paper is an
analysis of mistakes, made in the quantum theory development. One analyses
reasons of these mistakes and suggests methods of their correction.


title:
A Novel Method for the Solution of the Schroedinger Eq. in the Presence
  of Exchange Terms

abstract:
  In the Hartree-Fock approximation the Pauli exclusion principle leads to a
Schroedinger Eq. of an integro-differential form. We describe a new spectral
noniterative method (S-IEM), previously developed for solving the
Lippman-Schwinger integral equation with local potentials, which has now been
extended so as to include the exchange nonlocality. We apply it to the
restricted case of electron-Hydrogen scattering in which the bound electron
remains in the ground state and the incident electron has zero angular
momentum, and we compare the acuracy and economy of the new method to three
other methods. One is a non-iterative solution (NIEM) of the integral equation
as described by Sams and Kouri in 1969. Another is an iterative method
introduced by Kim and Udagawa in 1990 for nuclear physics applications, which
makes an expansion of the solution into an especially favorable basis obtained
by a method of moments. The third one is based on the Singular Value
Decomposition of the exchange term followed by iterations over the remainder.
The S-IEM method turns out to be more accurate by many orders of magnitude than
any of the other three methods described above for the same number of mesh
points.


title:
Nonresonant corrections to the 1s-2s two-photon resonance for the
  hydrogen atom

abstract:
  The nonresonant (NR) corrections are estimated for the most accurately
measured two-photon transition 1s-2s in the hydrogen atom. These corrections
depend on the measurement process and set a limit for the accuracy of atomic
frequency measurements. With the measurement process adopted in the modern
experiments the NR contribution for 1s-2s transition energy can reach 10^{-3}
Hz while the experimental inaccuracy is quoted to be +/- 46 Hz.


title: Guiding of cold atoms by a red-detuned laser beam of moderate power

abstract:
  We report measurements on the guiding of cold $^{87}$Rb atoms from a
magneto-optical trap by a continuous light beam over a vertical distance of 6.5
mm. For moderate laser power ($<$85 mW) we are able to capture around 40% of
the cold atoms. Although the guide is red-detuned, the optical scattering rate
at this detuning ($\approx$70 GHz) is acceptably low. For lower detuning ($<$30
GHz) a larger fraction was guided but radiation pressure starts to push the
atoms upward, effectively lowering the acceleration due to gravity. The
measured guided fraction agrees well with an analytical model.


title: Mark correlations: relating physical properties to spatial distributions

abstract:
  Mark correlations provide a systematic approach to look at objects both
distributed in space and bearing intrinsic information, for instance on
physical properties. The interplay of the objects' properties (marks) with the
spatial clustering is of vivid interest for many applications; are, e.g.,
galaxies with high luminosities more strongly clustered than dim ones? Do
neighbored pores in a sandstone have similar sizes? How does the shape of
impact craters on a planet depend on the geological surface properties? In this
article, we give an introduction into the appropriate mathematical framework to
deal with such questions, i.e. the theory of marked point processes. After
having clarified the notion of segregation effects, we define universal test
quantities applicable to realizations of a marked point processes. We show
their power using concrete data sets in analyzing the luminosity-dependence of
the galaxy clustering, the alignment of dark matter halos in gravitational
$N$-body simulations, the morphology- and diameter-dependence of the Martian
crater distribution and the size correlations of pores in sandstone. In order
to understand our data in more detail, we discuss the Boolean depletion model,
the random field model and the Cox random field model. The first model
describes depletion effects in the distribution of Martian craters and pores in
sandstone, whereas the last one accounts at least qualitatively for the
observed luminosity-dependence of the galaxy clustering.

categories: physics.data-an astro-ph cond-mat.stat-mech math.PR


title: Steady-State Properties of Single-File Systems with Conversion

abstract:
  We have used Monte-Carlo methods and analytical techniques to investigate the
influence of the characteristic parameters, such as pipe length, diffusion,
adsorption, desorption and reaction rate constants on the steady-state
properties of Single-File Systems with a reaction. We looked at cases when all
the sites are reactive and when only some of them are reactive. Comparisons
between Mean-Field predictions and Monte-Carlo simulations for the occupancy
profiles and reactivity are made. Substantial differences between Mean-Field
and the simulations are found when rates of diffusion are high. Mean-Field
results only include Single-File behavior by changing the diffusion rate
constant, but it effectively allows passing of particles. Reactivity converges
to a limit value if more reactive sites are added: sites in the middle of the
system have little or no effect on the kinetics. Occupancy profiles show
approximately exponential behavior from the ends to the middle of the system.


title:
Implementation of the Hough Transform for 3D Track Reconstruction in
  Drift Chambers

abstract:
  The paper is devoted to the method for 3D reconstruction of the straight
tracks in the tracking system consisting of the drift-chamber stereo layers.
The method is based on the Hough-transform approach - the discrete case of more
general Radon transform - and takes into account both coordinates of the hit
wires and drift distances not only for the measurements in one projection, but
also in the rotated stereo layers.
  The proposed method allows one to resolve the right-left ambiguity and
provides the accordance between vertical and horizontal projections of the
track.


title: Completely Positive Bloch-Boltzmann Equations

abstract:
  The density operator of the arbitrary physical system must be positive
definite. Employing the general master equation technique which preserves this
property we derive equations of motion for the density operator of an active
atom which interacts collisionally with the reservoir of perturber atoms. The
obtained general relations applied to the two-level atom yield Bloch-Boltzmann
equations (BBE). The form of the BBE obtained by us differs from that known
from literature which, as we show, are not guaranteed to preserve the required
positivity. We argue that our results are the correct ones and as such should
be used in practical applications. Moreover, the structure and the terms which
appear in our set of BBE seem to allow simpler and more straightforward
physical interpretation.


title:
On reflection from a half-space with negative real permittivity and
  permeability: Time-domain and frequency-domain results

abstract:
  The reflection of a normally incident wideband pulse by a half-space whose
permittivity and permeability obey the one-resonance Lorentz model is
calculated. The results are compared with those from frequency-domain
reflection analysis. In the spectral regime wherein the real parts of the
permittivity and the permeability are negative, as well as in small adjacent
neighborhoods of that regime, the time-domain analysis validates the conclusion
that it is sufficient to ensure that the imaginary part of the refractive index
is positive - regardless of the sign of the real part of the refractive index.


title: Trotter formula and thermodynamic limits

abstract:
  We discuss the interchangeability of the thermodynamic limit \beta \to \infty
and the infinite limit of the Trotter number n \to \infty when Trotter formula
e^{H_{0}+V} =\lim_{n \to \infty} (e^{H_{0}/n} e^{V/n}) is used to calculate
partition functions with Hamiltonians of the form H=H_{0}+V.


title:
Electron excitation and 'cascade' ionisation of diatomic molecules with
  ultra-short pulses of strong IR lasers

abstract:
  The dynamics of molecular electron excitation and ionisation is studied in
real-time for ultra-short IR laser pulses of intensity I>10^{13} W/cm^{2}. The
multi-electron molecule is modeled by a system of two active electrons moving
in a field of frozen core. The time dependences of electron probability,
electron energy, and one-electron/two-electron ionisation probability are
calculated for example of the N$_{2}$ molecule and the laser pulse with
\lambda=800 nm, \tau=5 fs. The electron dynamics of the pulse - excited
molecule is considered also after the pulse end. The results show that in the
strong IR pulses of I\ge 10^{16} W/cm^{2} the molecule undergoes a 'cascade'
ionisation, where the one electron is emitted with the same probability as a
pair of electrons.


title:
The Connection between the Quantum Frequency of Radiation and
  Frequencies of Circling of the Electron in Atom of Hydrogen

abstract:
  The connection between the quantum frequency of radiation by the transition
of the electron from orbit n to orbit k and frequencies of circling of electron
in these orbits for the atom of hydrogen is determined.


title: Elasticity and electromagnetism. Part 1: The Coulomb gauge

abstract:
  The Maxwell's electromagnetic equations are isomorphic to the motion equation
of a linear elastic continuum which is hard to compression though liable to
shear deformation. The Coulomb gauge expresses the medium incompressibility.
The magnetic vector potential corresponds to the medium velocity. The pressure
stands for the electrostatic potential. The electric field is modeled by an
external force whose origin is beyond the elastic model. The electric charge
corresponds to a medium defect which produces the perturbation 1/r of the
pressure field . The defects interact with each other due to the dilatation
center in the core of the inclusion.


title: Universality and Scale Invariance in Hourly Rainfall

abstract:
  We show that the hourly rainfall rate distribution can be described by a
simple power law to a good approximation. We show that the exponent of the
distribution in tropics is universal and is equal to $1.13\pm 0.11$. At higher
latitudes the exponent increases and is found to lie in the range 1.3-1.6.


title: The stochastic resonance mechanism in the Aerosol Index dynamics

abstract:
  We consider Aerosol Index (AI) time-series extracted from TOMS archive for an
area covering Italy $(7-18^o E ; 36-47^o N)$. The missing of convergence in
estimating the embedding dimension of the system and the inability of the
Independent Component Analysis (ICA) in separating the fluctuations from
deterministic component of the signals are evidences of an intrinsic link
between the periodic behavior of AI and its fluctuations. We prove that these
time series are well described by a stochastic dynamical model. Moreover, the
principal peak in the power spectrum of these signals can be explained whereby
a stochastic resonance, linking variable external factors, such as Sun-Earth
radiation budget and local insolation, and fluctuations on smaller spatial and
temporal scale due to internal weather and antrophic components.


title:
Reversed Circular Dichroism of Isotropic Chiral Mediums with Negative
  Real permeability and permittivity

abstract:
  Negative real parts of the permittivity and permeability lead an isotropic
chiral medium to exhibit circular dichroism that is reversed with respect to
that exhibited by an identical medium but the real parts of whose permittivity
and permeability are positive.


title:
Reversal of Circular Bragg Phenomenon in Ferrocholesteric Materials with
  Negative Real Permittivities and Permeabilities

abstract:
  A structurally right/left-handed ferrocholesteric slab with negative real
permittivities and permeabilities is theoretically shown to display the Bragg
phenomenon on axial excitation as if it were a structurally left/right-handed
ferrocholesteric slab with positive real permittivities and positive real
permeabilities. In addition to the promise of isotropic homogeneous materials
with negative real permittivities and permeabilities for unexpected
applications, the presented results underscore the similar potential of
anisotropic nonhomogeneous materials with analogous characteristics.


title: Temperature reconstruction analysis

abstract:
  This paper presents a wavelet multiresolution analysis of a time series
dataset to study the correlation between the real temperature data and three
temperature model reconstructions at different scales. We show that the Mann
et.al. model reconstructs the temperature better at all temporal resolutions.
We show and discuss the wavelet multiresolution analysis of the Mann's
temperature reconstruction for the period from 1400 to 2000 A.D.E.


title:
As-rich GaAs(001) surfaces observed during As4-irradition by scanning
  tunneling microscopy

abstract:
  As-rich GaAs (001) surfaces are successfully observed during As4-irradition
by a system in which scanning tunneling microscopy (STM) and molecular beam
epitaxy can be performed simultaneously. With a substrate temperature of 440 C
and an As4 partial pressure of 2x10-6 torr, reflection high energy electron
diffraction patterns and reflectance anisotropy spectra confirm a c(4x4)
As-stabilized surface. STM images clearly show alteration of the surface
reconstructions while scanning. It is postulated that continual attachment /
detachment of As molecules to and from the surface produces the observed
dynamic behavior.


title: Timing and Counting Precision in the Blowfly Visual System

abstract:
  We measure the reliability of signals at three levels within the blowfly
visual system, and present a theoretical framework for analyzing the
experimental results, starting from the Poisson process. We find that blowfly
photoreceptors, up to frequencies of 50-100 Hz and photon capture rates of up
to about 3*10^5/s, operate well within an order of magnitude from ideal photon
counters. Photoreceptors signals are transmitted to LMCs through an array of
chemical synapses. We quantify a lower bound on LMC reliability, which in turn
provides a lower bound on synaptic vesicle release rate, assuming Poisson
statistics. This bound is much higher than what is found in published direct
measurements of vesicle release rates in goldfish bipolar cells, suggesting
that release statistics may be significantly sub-Poisson. Finally we study H1,
a motion sensitive tangential cell in the fly's lobula plate, which transmits
information about a continuous signal by sequences of action potentials. In an
experiment with naturalistic motion stimuli performed on a sunny day outside in
the field, H1 transmits information at about 50% coding efficiency down to
millisecond spike timing precision. Comparing the measured reliability of H1's
response to motion steps with the bounds on the accuracy of motion computation
set by photoreceptor noise, we find that the fly's brain makes efficient use of
the information available in the photoreceptor array.


title:
Structure analysis of the Ga-stabilized GaAs(001)-c(8x2) surface at high
  temperatures

abstract:
  Structure of the Ga-stabilized GaAs(001)-c(8x2) surface has been studied
using rocking-curve analysis of reflection high-energy electron diffraction
(RHEED). The c(8x2) structure emerges at temperatures higher than 600C, but is
unstable with respect to the change to the (2x6)/(3x6) structure at lower
temperatures. Our RHEED rocking-curve analysis at high temperatures revealed
that the c(8x2) surface has the structure which is basically the same as that
recently proposed by Kumpf et al. [Phys. Rev. Lett. 86, 3586 (2001)]. We found
that the surface atomic configurations are locally fluctuated at high
temperatures without disturbing the c(8x2) periodicity.


title: Coherent light transport in a cold Strontium cloud

abstract:
  We study light coherent transport in the weak localization regime using
magneto-optically cooled strontium atoms. The coherent backscattering cone is
measured in the four polarization channels using light resonant with a J=0 to
J=1 transition of the Strontium atom. We find an enhancement factor close to 2
in the helicity preserving channel, in agreement with theoretical predictions.
This observation confirms the effect of internal structure as the key mechanism
for the contrast reduction observed with an Rubidium cold cloud (see: Labeyrie
et al., PRL 83, 5266 (1999)). Experimental results are in good agreement with
Monte-Carlo simulations taking into account geometry effects.


title:
Interference effects in the photorecombination of argonlike Sc3+ ions:
  Storage-ring experiment and theory

abstract:
  Absolute total electron-ion recombination rate coefficients of argonlike
Sc3+(3s2 3p6) ions have been measured for relative energies between electrons
and ions ranging from 0 to 45 eV. This energy range comprises all dielectronic
recombination resonances attached to 3p -> 3d and 3p -> 4s excitations. A broad
resonance with an experimental width of 0.89 +- 0.07 eV due to the 3p5 3d2 2F
intermediate state is found at 12.31 +- 0.03 eV with a small experimental
evidence for an asymmetric line shape. From R-Matrix and perturbative
calculations we infer that the asymmetric line shape may not only be due to
quantum mechanical interference between direct and resonant recombination
channels as predicted by Gorczyca et al. [Phys. Rev. A 56, 4742 (1997)], but
may partly also be due to the interaction with an adjacent overlapping DR
resonance of the same symmetry. The overall agreement between theory and
experiment is poor. Differences between our experimental and our theoretical
resonance positions are as large as 1.4 eV. This illustrates the difficulty to
accurately describe the structure of an atomic system with an open 3d-shell
with state-of-the-art theoretical methods. Furthermore, we find that a
relativistic theoretical treatment of the system under study is mandatory since
the existence of experimentally observed strong 3p5 3d2 2D and 3p5 3d 4s 2D
resonances can only be explained when calculations beyond LS-coupling are
carried out.


title: Effect of CH$_{4}$ addition on excess electron mobility in liquid Kr

abstract:
  The excess electrons mobility $\mu$ has been measured recently in liquid
mixtures of Kr and CH$_{4}$ as a function of the electric field up to $E\approx
10^{4} V/cm $ and of the CH$_{4}$ concentration $x$ up to $x \approx 10 % ,$ at
temperatures $T\approx 130 K,$ fairly close to the normal boiling point of Kr
$(T_{b}\approx 120 K)$(folegani). We present here new data which extend the
previous set in the region of low electric field. The experimental results are
interpreted in terms of a kinetic model previously proposed to explain the
concentration dependent behavior of $\mu$ in liquid Ar--Kr and Ar--Xe mixtures.
The main result is that CH$_{4}$ is more effective in enhancing
energy--transfer rather than momentum--transfer in comparison with mixtures of
liquified noble gases. The field dependence of $\mu$ is quite complicate. In
particular, at intermediate values of the field, there appears to be a
crossover between two different electric--field dependent behaviors of $\mu.$
The electric field strength at crossover is well correlated with the
concentration of CH$_{4}.$ This fact suggests that different excitations of the
molecular solute might be involved in the momentum-- and energy--transfer
processes for different values of the mean electron energy.


title:
An easy method to estimate charge-exchange cross sections between ions
  and one-active-electron atoms

abstract:
  In this paper we present a simple model for computing single electron
exchange between light nuclei. The electronic capture is pictured as a
tunnelling process in a model potential. This allows to analytically compute
the transmission probability. Some comparisons with data from existing
literature are given.


title: Quantum effects in the scattering by the magnetic field of a solenoid

abstract:
  We present a relativistic quantum calculation at first order in perturbation
theory of the differential cross section for a Dirac particle scattered by the
magnetic field of a solenoid. The resulting cross section is symmetric in the
scattering angle as those obtained by Aharonov and Bohm (AB) in the string
limit and by Landau and Lifshitz (LL) for the non relativistic case. We show
that taking pr_0 sin(theta/2) << 1 in our expression of the differential cross
section it reduces to that one reported by AB, and if additionally we assume
theta << 1 our result becomes the one obtained by LL. However, these limits are
explicitly singular in hbar as opposed to our initial result. We analyse the
singular behavior in hbar and show that the perturbative Planck limit (hbar ->
0) is consistent, contrarily to those of the AB and LL expressions.

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