title:
The challenge of changing deeply-held student beliefs about the
  relativity of simultaneity

abstract:
  Previous research indicates that after standard instruction students at all
academic levels often construct a conceptual framework in which the ideas of
absolute simultaneity and the relativity of simultaneity co-exist. This article
describes the development and assessment of instructional materials intended to
improve student understanding of the concept of time in special relativity, the
relativity of simultaneity, and the role of observers in inertial reference
frames. Results from pretests and post-tests are presented to demonstrate the
effect of the curriculum in helping students deepen their understanding of
these topics. Excerpts from taped interviews and classroom interactions help
illustrate the intense cognitive conflict that students encounter as they are
led to confront the incompatibility of their deeply-held beliefs about
simultaneity with the results of special relativity.


title:
Revisiting the Complexity of Finding Globally Minimum Energy
  Configurations in Atomic Clusters

abstract:
  It has previously been proven that finding the globally minimum energy
configuration of an atomic cluster belongs in the class of NP-hard problems.
However, this proof is limited only to homonuclear clusters. This paper
presents a new proof which shows finding minimum energy configurations for
heteronuclear clusters is also NP-hard.


title: A Measure of the Goodness of Fit in Unbinned Likelihood Fits

abstract:
  Maximum likelihood fits to data can be done using binned data (histograms)
and unbinned data. With binned data, one gets not only the fitted parameters
but also a measure of the goodness of fit. With unbinned data, currently, the
fitted parameters are obtained but no measure of goodness of fit is available.
This remains, to date, an unsolved problem in statistics. Using Bayes theorem
and likelihood ratios, we provide a method by which both the fitted quantities
and a measure of the goodness of fit are obtained for unbinned likelihood fits,
as well as errors in the fitted quantities. We provide an ansatz for
determining Bayesian a priori probabilities.


title: Cluster growing process and a sequence of magic numbers

abstract:
  We present a new theoretical framework for modelling the cluster growing
process. Starting from the initial tetrahedral cluster configuration, adding
new atoms to the system and absorbing its energy at each step, we find cluster
growing paths up to the cluster sizes of more than 100 atoms. We demonstrate
that in this way all known global minimum structures of the Lennard-Jonnes (LJ)
clusters can be found. Our method provides an efficient tool for the
calculation and analysis of atomic cluster structure. With its use we justify
the magic numbers sequence for the clusters of noble gases atoms and compare it
with experimental observations. We report the striking correspondence of the
peaks in the dependence on cluster size of the second derivative of the binding
energy per atom calculated for the chain of LJ-clusters based on the
icosahedral symmetry with the peaks in the abundance mass spectra
experimentally measured for the clusters of noble gases atoms. Our method
serves an efficient alternative to the global optimization techniques based on
the Monte-Carlo simulations and it can be applied for the solution of a broad
variety of problems in which atomic cluster structure is important.


title:
On the applicability of jellium model to the description of alkali
  clusters

abstract:
  This work is devoted to the elucidation the applicability of jellium model to
the description of alkali cluster properties on the basis of comparison the
jellium model results with those derived from experiment and within ab initio
theoretical framework. On the basis of the Hartree-Fock and local-density
approximation deformed jellium model we have calculated the binding energies
per atom, ionization potentials, deformation parameters and the optimized
values of the Wigner-Seitz radii for neutral and singly charged sodium clusters
with the number of atoms N <= 20. These characteristics are compared with the
results derived from the ab initio all-electron simulations of cluster
electronic and ionic structure based on the density functional theory as well
as on the post Hartree-Fock perturbation theory on many-electron correlation
interaction. The comparison performed demonstrates the great role of cluster
shape deformations in the formation cluster properties and the quite reasonable
level of applicability of the deformed jellium model.


title: Multiple solutions of CCD equations for PPP model of benzene

abstract:
  To gain some insight into the structure and physical significance of the
multiple solutions to the coupled-cluster doubles (CCD) equations corresponding
to the Pariser-Parr-Pople (PPP) model of cyclic polyenes, complete solutions to
the CCD equations for the A^{-}_{1g} states of benzene are obtained by means of
the homotopy method. By varying the value of the resonance integral beta from
-5.0 eV to -0.5 eV, we cover the so-called weakly, moderately, and strongly
correlated regimes of the model. For each value of beta 230 CCD solutions are
obtained. It turned out, however, that only for a few solutions a
correspondence with some physical states can be established. It has also been
demonstrated that, unlike for the standard methods of solving CCD equations,
some of the multiple solutions to the CCD equations can be attained by means of
the iterative process based on Pulay's direct inversion in the iterative
subspace (DIIS) approach.


title: Transient behavior in Single-File Systems

abstract:
  We have used Monte-Carlo methods and analytical techniques to investigate the
influence of the characteristics, such as pipe length, diffusion, adsorption,
desorption and reaction rates on the transient properties of Single-File
Systems. The transient or the relaxation regime is the period in which the
system is evolving to equilibrium. We have studied the system when all the
sites are reactive and when only some of them are reactive. Comparisons between
Mean-Field predictions, Cluster Approximation predictions, and Monte Carlo
simulations for the relaxation time of the system are shown. We outline the
cases where Mean-Field analysis gives good results compared to Dynamic
Monte-Carlo results. For some specific cases we can analytically derive the
relaxation time. Occupancy profiles for different distribution of the sites
both for Mean-Field and simulations are compared. Different results for slow
and fast reaction systems and different distribution of reactive sites are
discussed.


title:
Characterization and modelling of the hollow beam produced by a real
  conical lens

abstract:
  The properties of the hollow beam produced by a conical lens are studied in
detail. In particular, the impact of a rounded vertex is examined. It is shown
that it could lead to drastic changes in the transverse distribution of the
hollow beam, determined by the ratio between the transverse size of the
incident beam and the size of the blunt area. An adequate choice for this ratio
allows us to either minimize the losses or optimize the distribution symmetry.


title:
Scintillator-photodiode type detectors for multi-energy scanning
  introscopy

abstract:
  Results of experimental studies of detector arrays S-PD
(scintillator-photodiode) and PRD (scintillator-photoreceiving device) used for
X-ray digital radiography have shown that there exist further possibilities to
increase spatial resolution of this system up to 2-3 line pairs per mm.
Theoretical analysis and experimental studies show that the two-energy
detection method not only allows one to detect organics on the background of
metal, but also substantially increases (by 3-5 times) the detection ability of
the system as a whole, especially if parameters of the S-PD pair are optimized,
in particular, when ZnSe(Te) is used in the low-energy circuit. A possibility
to distinguish, in principle, between substances with insignificant differences
in atomic number has been theoretically proven -- by transition to multi-energy
radiography. 3D-imaging has been realized using S-PD detector arrays.

categories: physics.ins-det hep-ex physics.gen-ph physics.soc-ph


title:
Student Resources in Quantum Mechanics, or Why Students Need
  Meta-resources

abstract:
  We are trying to identify resources students are using to reason in quantum
mechanics. In this process we realize students must have not only the right
resources available but sophisticated for evaluating and controlling their
thought processes. We will discuss examples from student interviews to
illustrate our point.


title: Gravitation and electromagnetism

abstract:
  Maxwell's equations comprise both electromagnetic and gravitational fields.
The transverse part of the vector potential belongs to magnetism, the
longitudinal one is concerned with gravitation. The Coulomb gauge indicates
that longitudinal components of the fields propagate instantaneously. The
delta-function singularity of the field of the divergence of the vector
potential, referred to as the dilatation center, represents an elementary agent
of gravitation. Viewing a particle as a source or a scattering center of the
point dilatation, the Newton's gravitation law can be reproduced.


title: Making Sense of How Students Make Sense of Mechanical Waves

abstract:
  We report on our study of student understanding of the physics of mechanical
waves, specifically the propagation and superposition of simple wavepulses
traveling on long, taut strings. We introduce the terms "particle pulses mental
model" to describe the reasoning approach that students use to guide their
thinking in wave propagation and superposition. Student responses on free
response and multiple-choice, multiple response questions dealing with the same
physics show inconsistent student thinking, where they may have both correct
and incorrect ideas about the concepts.


title: Mathematical Tutorials in Introductory Physics

abstract:
  Students in introductory calculus-based physics not only have difficulty
understanding the fundamental physical concepts, they often have difficulty
relating those concepts to the mathematics they have learned in math courses.
This produces a barrier to their robust use of concepts in complex problem
solving. As a part of the Activity-Based Physics project, we are carrying out
research on these difficulties and are developing instructional materials in
the tutorial framework developed at the University of Washington by Lillian C.
McDermott and her collaborators. In this paper, we present a discussion of
student difficulties and the development of a mathematical tutorial on the
subject of pulses moving on strings.


title: Fermi and Szilard

abstract:
  Enrico Fermi and Leo Szilard worked together at Columbia in 1939-40, just
after nuclear fission was discovered, to ascertain the feasibility of a nuclear
chain reaction, and then on the construction of the first nuclear reactor.
Szilard believed a nuclear bomb could be built, and that the Germans may be
doing so, but Fermi was sceptical. The Anglo-American project to build a bomb
began late in 1941 after Oliphant brought the Frisch-Peierls memorandum to the
attention of U. S. physicists. Szilard recalled "On matters scientific or
technical there was rarely any disagreement[but] Fermi and I disagreed from the
very start of our collaboration about every issue that involved not science but
principles of action in the face of the approaching war. If the nation owes us
gratitude - and it may not - it does so for having stuck it out together as
long as was necessary." As the war with Germany was drawing to a close and the
successful construction of the atomic bombs was well underway, these two men
took opposing positions regarding use of the bombs.


title: T-Quark Mass and Hyperfinite II1 von Neumann factor

abstract:
  A theoretical model based on the D4 Lie Algebra and Hermitian Symmetric
Spaces D5 / D4xU(1) and E6 / D5xU(1) allows calculation of ratios of tree-level
particle masses (quark masses being constituent masses): Me-neutrino =
Mmu-neutrino = Mtau-neutrino = 0 Me = 0.5110 MeV (assumed); Md = Mu = 312.8
MeV; Mmu = 104.8 MeV; Ms = 625 MeV; Mc = 2.09 GeV; Mtau = 1.88 GeV; Mb = 5.63
GeV; Mt = 130 GeV; W+/- mass = 80.326 GeV; Z0 mass = 91.862 GeV; Higgs mass =
145.8 GeV; Higgs VEV = 252.5 GeV; and ratios of force strength constants:
(Ggravity)(Mproton)2 = 5 x 10-39 (asssumed); EM fine structure constant =
1/137.03608; Gfermi = (Gweak)(Mproton)2 = 1.02 x 10-5; color force strength =
0.6286 (at 0.245 GeV). With Nonperturbative QCD etc taken into account the
color force strength = 0.123 (at 91 GeV). Fermilab (1994) says that Mt = about
170 GeV but I say (1984) that Mt = about 130 GeV. The theoretical Lagrangian is
based on the structure of the real Cl(1,7) Clifford algebra which, through
8-fold periodicity, may produce a real Hyperfinite II1 von Neumann Algebra
factor.


title: Infinite square well and periodic trajectories in classical mechanics

abstract:
  We examine the classical problem of an infinite square well by considering
Hamilton's equations in one dimension and Hamilton-Jacobi equation for motion
in two dimensions. We illustrate, by means of suitable examples, the nature of
the periodic motion of a particle trapped inside the well.


title: A Kalman Filter for Ocean Monitoring

abstract:
  The feasibility of global ocean state estimation by sequential data
assimilation is demonstrated. The model componenet of the assimilator is the
GROB version of the MPIMET ocean circulation model HOPE. Assimilation uses the
Fokker-Planck representation of the Kalman Filter. This approach determines the
temporal evolution of error statistics by integration of the Fokker-Planck
Equation. Phase space advection and diffusion are obtained from histogram
techniques considering the model as a black box. For efficiency, the estimate
combines nudging and Kalman Filtering. The ocean state is estimated for the El
Nino year 1997 by dynamical extrapolation of observed sea-surface temperatures
and TAO/Triton subsurface temperatures. The model-data combination yields
improved estimates of the ocean's mean state and a realistic record of El Nino
related variability. The assimilator proves as an efficient, viable and thus
practical approach to operational global ocean state estimation.


title:
Magnetic field control of elastic scattering in a cold gas of fermionic
  lithium atoms

abstract:
  We study elastic collisions in an optically trapped spin mixture of fermionic
lithium atoms in the presence of magnetic fields up to 1.5kG by measuring
evaporative loss. Our experiments confirm the expected magnetic tunability of
the scattering length by showing the main features of elastic scattering
according to recent calculations. We measure the zero crossing of the
scattering length that is associated with a predicted Feshbach resonance at
530(3)G. Beyond the resonance we observe the expected large cross section in
the triplet scattering regime.


title: The Software Anatomy of a Flexible Accelerator Simulation Engine

abstract:
  A modular, maintainable and extensible particle beam simulation architecture
is presented. Design considerations for single particle, multi particle, and
rms envelope simulations (in two and three dimensions) are outlined. Envelope
simulation results have been validated against Trace3D. Hybridization with a
physics-centric contol-system abstraction provides a convenient environment for
rapid deployment of applications employing model-reference control strategies.


title: Behavior of Electric Current Subjected to ELF Electromagnetic Radiation

abstract:
  Gravitational effects produced by ELF electromagnetic radiation upon the
electric current in a conductor are studied. An apparatus has been constructed
to test the behavior of current subjected to ELF radiation. The experimental
results are in agreement with theoretical predictions and show that ELF
radiation can cause transitory interruptions in electric current conduction.


title:
Feedback processes in cellulose thermal decomposition. Implications for
  fire-retarding strategies and treatments

abstract:
  A simple dynamical system that models the competitive thermokinetics and
chemistry of cellulose decomposition is examined, with reference to evidence
from experimental studies indicating that char formation is a low activation
energy exothermal process and volatilization is a high activation energy
endothermal process. The thermohydrolysis chemistry at the core of the primary
competition is described. Essentially, the competition is between two
nucleophiles, a molecule of water and an -OH group on C_6 of an end glucosyl
cation, to form either a reducing chain fragment with the propensity to undergo
the bond-forming reactions that ultimately form char or a
levoglucosan-end-fragment that depolymerizes to volatile products. The results
of this analysis suggest that promotion of char formation under thermal stress
can actually increase the production of flammable volatiles. Thus we would like
to convey an important safety message in this paper: in some situations where
heat and mass transfer is restricted in cellulosic materials, such as
furnishings, insulation, and stockpiles, the use of char-promoting treatments
for fire retardation may have the effect of increasing the risk of flaming
combustion.


title:
Global Spatiotemporal Order and Induced Stochastic Resonance due to a
  Locally Applied Signal

abstract:
  We study the phenomenon of spatiotemporal stochastic resonance (STSR) in a
chain of diffusively coupled bistable oscillators. In particular, we examine
the situation in which the \textit{global} STSR response is controlled by a
\textit{locally applied signal} and reveal a wave front propagation. In order
to deepen the understanding of the system dynamics, we introduce, on the time
scale of STSR, the study of the effective statistical renormalization of a
generic lattice system. Using this technique we provide a new criterion for
STSR, and predict and observe numerically a bifurcation-like behaviour that
reflects the difference between the most probable value of the local
quasi-equilibrium density and its mean value. Our results, tested with a chain
of nonlinear oscillators, appear to possess some universal qualities and may
stimulate a deeper search for more generic phenomena


title: Perturbative approach to the hydrogen atom in strong magnetic field

abstract:
  The states of hydrogen atom with principal quantum number n <= 3 and zero
magnetic quantum number in constant homogeneous magnetic field H are
considered. The perturbation theory series is summed with the help of Borel
transformation and conformal mapping of the Borel variable. Convergence of
approximate energy eigenvalues and their agreement with corresponding existing
results are observed for external fields up to n^3 H ~ 5. The possibility of
restoring the asymptotic behaviour of energy levels using perturbation theory
coefficients is also discussed.


title: Representative Pathways of Excitation Migration in Photosystem I

abstract:
  Photosystem I is a protein-pigment complex that performs photosynthesis in
plants, green algae, and cyanobacteria. It contains an aggregate of
chlorophylls that absorbs light and delivers the resulting electronic
excitation to the special pair of chlorophylls where the excitation energy is
used for producing charge separation across the cell membrane. The seemingly
random arrangement of chlorophylls in photosystem I poses the question which
pathways excitation migration follows towards the special pair after absorption
of light at any of its chlorophylls. We employ a master equation to describe
the process of excitation migration in photosystem I, and find representative
paths of excitation migration based on the mean first-passage time from each
chlorophyll to the special pair. The resulting paths, beginning at each of the
chlorophylls and ending at the special pair, provide a complete yet distilled
picture of the excitation migration towards the special pair.


title: Collision rates in near-resonant optical lattices

abstract:
  We present a simple method to calculate the binary collision rate between
atoms in near-resonant optical lattices. The method is based on the Monte Carlo
wave function simulations and the collision rate is obtained by monitoring the
quantum flux beyond the average distance between the atoms. To illustrate the
usefulness of the method, we calculate the collision rates for a wide range of
occupation densities and various modulation depths of the lattice. The method
presented here combined with the semiclassical calculations accounting for
intra-well collisions can simplify the study of the effects of binary
collisions on the dynamics of atomic clouds trapped in near-resonant optical
lattices.


title:
Effectiveness of group interaction on conceptual standardized test
  performance

abstract:
  We analyze the effectiveness of working in pairs on the Conceptual Survey of
Electricity and Magnetism test in a calculus-based introductory physics course.
The group performance shows large normalized gain and evidence for
co-construction. We discuss the effect of pairing students with different
individual achievements.


title: On the Equation H=mv^2 and the Fine Structure of the Hydrogen Atom

abstract:
  The recently introduced reconciliation of the theories of special relativity
and wave mechanics implies that the mass-energy equivalence principle must be
expressed mathematically as H = mv^2, where H is the total energy of a
particle, m is its relativistic mass, and v is its velocity; not H = mc^2 as
was widely believed. In this paper, the equation H = mv^2 will be used to
calculate the energy levels in the spectrum of the hydrogen atom. It is
demonstrated that the well-known Sommerfeld-Dirac formula is still obtained,
but without the constant term m_0 c^2 that was originally present in the
formula.


title:
Richardson's pair diffusion and the stagnation point structure of
  turbulence

abstract:
  DNS and laboratory experiments show that the spatial distribution of
straining stagnation points in homogeneous isotropic 3D turbulence has a
fractal structure with dimension D_s = 2. In Kinematic Simulations the time
exponent gamma in Richardson's law and the fractal dimension D_s are related by
gamma = 6/D_s. The Richardson constant is found to be an increasing function of
the number of straining stagnation points in agreement with pair duffusion
occuring in bursts when pairs meet such points in the flow.


title:
Student understanding of time in special relativity: simultaneity and
  reference frames

abstract:
  This article reports on an investigation of student understanding of the
concept of time in special relativity. A series of research tasks are discussed
that illustrate, step-by-step, how student reasoning of fundamental concepts of
relativity was probed. The results indicate that after standard instruction
students at all academic levels have serious difficulties with the relativity
of simultaneity and with the role of observers in inertial reference frames.
Evidence is presented that suggests many students construct a conceptual
framework in which the ideas of absolute simultaneity and the relativity of
simultaneity harmoniously co-exist.


title: A steepest descent calculation of RNA pseudoknots

abstract:
  We enumerate possible topologies of pseudoknots in single-stranded RNA
molecules. We use a steepest-descent approximation in the large N matrix field
theory, and a Feynman diagram formalism to describe the resulting pseudoknot
structure.


title: Alternative explanation of the nature of line clumps

abstract:
  It is assumed, that the clumps of lines do not connected with states mixing
and IVR, but they are the result of breaking (destruction) of the process of
averaging of momentum of inertia of molecules during the vibration motion of
atoms. Rough estimates of the widths of clumps of lines in absorption spectra
of some acetylenic derivatives were made with this model. Obtained results are
in a satisfactory agreement with the available experimental data. This idea
allows also in principle to explain the origin of intensive wings of lines, the
existence of which was discussed earlier.


title:
Generation of multiscale magnetic field by parity-invariant
  time-periodic flows

abstract:
  We study generation of magnetic fields involving large spatial scales by
time- and space-periodic small-scale parity-invariant flows. The anisotropic
magnetic eddy diffusivity tensor is calculated by the standard procedure
involving expansion of magnetic modes and their growth rates in power series in
the scale ratio. Our simulations, conducted for flows with random harmonic
composition and exponentially decaying energy spectra, demonstrate that
enlargement of the spatial scale of magnetic field is beneficial for generation
by time-periodic flows. However, they turn out, in general, to be less
efficient dynamos, than steady flows.


title: Simplifying the mosaic description of DNA sequences

abstract:
  By using the Jensen-Shannon divergence, genomic DNA can be divided into
compositionally distinct domains through a standard recursive segmentation
procedure. Each domain, while significantly different from its neighbours, may
however share compositional similarity with one or more distant
(non--neighbouring) domains. We thus obtain a coarse--grained description of
the given DNA string in terms of a smaller set of distinct domain labels. This
yields a minimal domain description of a given DNA sequence, significantly
reducing its organizational complexity. This procedure gives a new means of
evaluating genomic complexity as one examines organisms ranging from bacteria
to human. The mosaic organization of DNA sequences could have originated from
the insertion of fragments of one genome (the parasite) inside another (the
host), and we present numerical experiments that are suggestive of this
scenario.


title:
New Hierarchic Theory of Water and its Application to Analysis of Water
  Perturbations by Magnetic Field. Role of Water in Biosystems

abstract:
  The short version of new quantum quantitative Hierarchic theory, general for
solids and liquids is presented. Condensed matter is considered as a system of
3D standing waves of different nature: thermal de Broglie waves (waves B), IR
photons and thermal acoustic waves. Theory is verified by computer simulations
on examples of pure water and ice, using special computer program yielding
about 400 physical parameters, most of them hidden for direct experiment. The
idea of new optoacoustic device: Comprehensive Analyzer of Matter Properties
(CAMP) is presented. Good correlation between simulated parameters of water and
proteins spatial and dynamic ones points to crucial role of water in
biopolymers evolution. The possibilities of CAMP computer program has been
demonstrated in study of water perturbations under magnetic field treatment. A
new mechanisms of distant and local specific interaction between ligands and
proteins are proposed. Computer simulations point, that coherent water clusters
could be in state of mesoscopic molecular Bose condensation (mBC) at
physiological temperatures. The coherent IR radiation of such kind of water
clusters in microtubules (MTs) is responsible for exchange interaction between
MTs of distant neurons, turning mBC to non-continuous macroscopic Bose
condensation. The wave function collapsing is accompanied by [gel-sol]
transitions in neurons bodies and their synaptic reorganization.


title: The dangerous misconceptions of Sir Karl Raimund Popper

abstract:
  Insofar as Sir Karl Raimund Popper's writings deal with political statements,
they are evident; yet insofar as they deal with scientific issues, they are
misleading. If applied to the concrete implementation of science, such as
distribution of research funds and (peer) review, they would seriously impede
progress.


title:
Work functions, ionization potentials, and in-between: Scaling relations
  based on the image charge model

abstract:
  We revisit a model in which the ionization energy of a metal particle is
associated with the work done by the image charge force in moving the electron
from infinity to a small cut-off distance just outside the surface. We show
that this model can be compactly, and productively, employed to study the size
dependence of electron removal energies over the range encompassing bulk
surfaces, finite clusters, and individual atoms. It accounts in a
straightforward manner for the empirically known correlation between the atomic
ionization potential (IP) and the metal work function (WF), IP/WF$\sim$2. We
formulate simple expressions for the model parameters, requiring only a single
property (the atomic polarizability or the nearest neighbor distance) as input.
Without any additional adjustable parameters, the model yields both the IP and
the WF within $\sim$10% for all metallic elements, as well as matches the size
evolution of the ionization potentials of finite metal clusters for a large
fraction of the experimental data. The parametrization takes advantage of a
remarkably constant numerical correlation between the nearest-neighbor distance
in a crystal, the cube root of the atomic polarizability, and the image force
cutoff length. The paper also includes an analytical derivation of the relation
of the outer radius of a cluster of close-packed spheres to its geometric
structure.


title:
Real-time determination of free energy and losses in optical absorbing
  media

abstract:
  We introduce notions of free energy and loss in linear, absorbing dielectric
media which are relevant to the regime in which the macroscopic Maxwell
equations are themselves relevant. As such we solve a problem eluded to by
Landau and Lifshitz in 1958, and later considered explicitly by Barash and
Ginzburg, and Oughtsun and Sherman. As such we provide physically-relevant
real-time notions of "energy" and "loss" in all analogous linear dissipative
systems.


title:
Economics from a Physicist's point of view: Stochastic Dynamics of
  Supply and Demand in a Single Market. Part I

abstract:
  Proceeding from the concept of rational expectations, a new dynamic model of
supply and demand in a single market with one supplier, one buyer, and one kind
of commodity is developed. Unlike the cob-web dynamic theories with adaptive
expectations that are made up of deterministic difference equations, the new
model is cast in the form of stochastic differential equations. The
stochasticity is due to random disturbances ("input") to endogenous variables.
The disturbances are assumed to be stationary to the second order with zero
means and given covariance functions. Two particular versions of the model with
different endogenous variables are considered. The first version involves
supply, demand, and price. In the second version the stock of commodity is
added. Covariance functions and variances of the endogenous variables
("output") are obtained in terms of the spectral theory of stochastic
stationary processes. The impact of both deterministic parameters of the model
and the random input on the stochastic output is analyzed and new conditions of
chaotic instability are found. If these conditions are met, the endogenous
variables undergo unbounded chaotic oscillations. As a result, the market that
would be stable if undisturbed loses stability and collapses. This phenomenon
cannot be discovered even in principle in terms of any cobweb deterministic
model.


title:
Application of path integral formalism to spectral line broadening:
  lyman alpha in hydrogenic plasma

abstract:
  In this paper the results of Lyman alpha line shapes without the fine
structure in the electron impact approximation are rederived using a path
integral formalism. The method presented here is designed to provide a quantum
formalism that will treat the ions and the electrons on the same physical
basis. This method has also the advantage of treating cases where the dynamical
effects are present. We therefore, give an expression of the dipolar
autocorrelation function taking into account the ion dynamics effects.


title: Fermions as topological objects

abstract:
  A preon-based composite model of the fundamental fermions is discussed, in
which the fermions are bound states of smaller entities -- primitive charges
(preons). The preon is regarded as a dislocation in a dual 3-dimensional
manifold -- a topological object with no properties, save its unit mass and
unit charge. It is shown that the dualism of this manifold gives rise to a
hierarchy of complex structures resembling by their properties three families
of the fundamental fermions. Although just a scheme for building a model of
elementary particles, this description yields a quantitative explanation of
many observable particle properties, including their masses.


title: Wetting to Non-wetting Transition in Sodium-Coated C_60

abstract:
  Based on ab initi and density-functional theory calculations, an empirical
potential is proposed to model the interaction between a fullerene molecule and
many sodium atoms. This model predicts homogeneous coverage of C_60 below 8 Na
atoms, and a progressive droplet formation above this size. The effects of
ionization, temperature, and external electric field indicate that the various,
and apparently contradictory, experimental results can indeed be put into
agreement.


title: Optical Kerr type nonlinearity

abstract:
  The origin of the Kerr type nonlinearity of the medium as a result of the
interaction between photons via the Dirac delta-potential is presented in the
formalism adopted from the photon wave function approach. In the view of the
result the optical soliton may be treated as a bound state (cluster) of many
photons.


title:
Low Temperature Electronic Transport and Electron Transfer through
  Organic Macromolecules

abstract:
  It is shown that at low temperatures and moderate electron dephasing the
electron transmission function reveales a structure containing information
about donor/acceptor sites effectively participating in the electron transfer
(ET) processes and primary pathways of electrons tunneling through molecular
bridges in macromolecules. This important information can be obtained as a
result of analysis of experimental low temperature current-voltage
characteristics for chosen molecules.


title: On the electrostatic potential profile in biased molecular wires

abstract:
  The potential profile across a biased molecular junction is calculated within
the framework of a simple Thomas-Fermi type screening model. In particular, the
relationship between this profile and the lateral molecular cross section is
examined. We find that a transition from a linear potential profile to a
potential that drops mainly near the molecule-metal contacts occurs with
increasing cross section width, in agreement with numerical quantum
calculations.


title: Marginalization using the metric of the likelihood

abstract:
  Although the likelihood function is normalizeable with respect to the data
there is no guarantee that the same holds with respect to the model parameters.
This may lead to singularities in the expectation value integral of these
parameters, especially if the prior information is not sufficient to take care
of finite integral values. However, the problem may be solved by obeying the
correct Riemannian metric imposed by the likelihood. This will be demonstrated
for the example of the electron temperature evaluation in hydrogen plasmas.


title:
Drift Wave versus Interchange Turbulence in Tokamak Geometry: Linear
  versus Nonlinear Mode Structure

abstract:
  The competition between drift wave and interchange physics in general
E-cross-B drift turbulence is studied with computations in three dimensional
tokamak flux tube geometry. For a given set of background scales, the parameter
space can be covered by the plasma beta and drift wave collisionality. At large
enough plasma beta the turbulence breaks out into ideal ballooning modes and
saturates only by depleting the free energy in the background pressure
gradient. At high collisionality it finds a more gradual transition to
resistive ballooning. At moderate beta and collisionality it retains drift wave
character, qualitatively identical to simple two dimensional slab models. The
underlying cause is the nonlinear vorticity advection through which the self
sustained drift wave turbulence supersedes the linear instabilities, scattering
them apart before they can grow, imposing its own physical character on the
dynamics. This vorticity advection catalyses the gradient drive, while
saturation occurs solely through turbulent mixing of pressure disturbances.
This situation persists in the whole of tokamak edge parameter space. Both
simplified isothermal models and complete warm ion models are treated.


title:
Reversible and irreversible processes in dispersive/dissipative optical
  media: Electro-magnetic free energy and heat production

abstract:
  We solve the problem addressed by Landau and Lifshitz in 1958, and Oughstun
and Sherman of determining the dynamical losses in a purely dissipative
dielectric media. We develop concrete notions of macroscopic free energy and
losses as energy which is reversible and irreversible, respectively, in the
medium-field interaction. We define the reversible and irreversible energies
and outline the derivation of said quantities. We examine the implications of
our definition and it's auxiliary quantity, the reversal field, for the single
Lorentz oscillator model of a medium. We show that for this model the
reversible energy reduces to the sum of the kinetic and potential energy, as
found by Loudon. We note that in general, the sum of the kinetic and potential
energies is greater than the reversible energy. We show that the reversible and
irreversible energy have the characteristics classically defining free energy
and heat.


title: Propagation of photons in resting and moving media

abstract:
  The propagation of photon in a dielectric may be described with the help of
the scalar and vector potentials of the medium. The main novelty of the paper
is that the concept of the vector potential (which is connected with the
velocity of the medium) can be extended to relativistic velocities of the
medium. The position-dependent photon wave function was used to describe the
propagation of the photon. The new concepts of the velocity of photon as
particle and the photon mass in the dielectric medium were proposed.


title:
In-Vivo NMR of Hyperpolarized Helium-3 in the Human Lung at Very Low
  Magnetic Fields

abstract:
  We present NMR measurements of the diffusion of hyperpolarized helium-3 in
the human lung performed at fields much lower than those of conventional MRI
scanners. The measurements were made on standing subjects using homebuilt
apparatus operating at 3 mT. Oxygen-limited transverse relaxation (T2 up to
15-35 s) could be measured in-vivo. Accurate global diffusion measurements have
been performed in-vivo and in-vitro. 1D ADC mapping with high SNR demonstrates
the real possibility of performing quality lung imaging at extremely low
fields.


title:
Towards a model of incoherent scatter signal spectra without averaging
  over sounding runs

abstract:
  This paper offers a model for incoherent scatter signal spectra without
averaging the received signal over sounding runs (realizations). The model is
based on the existent theory of radio waves single scattering from the medium
dielectric permittivity irregularities, and on the existing kinetic theory of
the plasma thermal irregularities. The proposed model is obtained for the case
of monostatic sounding. The model shows that the main contribution to the
received signal is made by ion-acoustic waves caused by certain spatial
harmonics of the ions number phase density. The model explains the width and
form of the signal spectrum by macroscopic characteristics of the medium, and
its fine 'peaked' structure by characteristics of the ions number phase
density. The notion of the weight volume is introduced to define the domain of
wave vectors and velocities in the spatial spectrum of the ions number phase
density which makes the main contribution to the formation of the scattered
signal. This weight volume depends on the antenna pattern, the form of the
sounding signal, and on the time window of spectral processing, as well as on
ionospheric plasma macroscopic parameters: electron and ion temperatures, ion
composition, and the drift velocity. Within the context of additional
assumption about the ions number phase density, the proposed model was tested
by the data from the Irkutsk incoherent scatter radar. The test showed a good
fit of the model to experiment.


title: The Character of Transport Caused by ExB Drift Turbulence

abstract:
  The basic character of diffusive transport in a magnetised plasma depends on
what kind of transport is modelled. ExB turbulence under drift ordering has
special characteristics: it is nearly incompressible, and it cannot lead to
magnetic flux diffusion if it is electrostatic. The ExB velocity is also
related to the Poynting energy flux. Under quasineutral dynamics, electric
fields are not caused by transport of electric charge but by the requirement
that the total current is divergence free. Consequences for well constructed
computational transport models are discussed in the context of a general mean
field analysis, which also yields several anomalous transfer mechanisms not
normally considered by current models.


title: Towards a new technique of incoherent scatter signal processing

abstract:
  This paper offers a new technique of incoherent scattering signal processing.
The technique is based on the experimentally observed comb structure of the
spectral power of separate realizations. The technique implies determining the
positions and amplitudes of peaks in separate realizations, the formation - on
their basis - of the spectral power of an individual realization not distorted
by the smoothing function, and a subsequent summation of such spectra for the
realizations. The technique has been tested using data from the Irkutsk
incoherent scatter radar, both for the case of the incoherent scattering from
thermal irregularities of plasma and for the case of the aspect scattering from
instabilities elongated with the geomagnetic field.

categories: physics.ao-ph physics.data-an physics.plasm-ph physics.space-ph


title: Experiment and Theory in Computations of the He Atom Ground State

abstract:
  Extensive variational computations are reported for the ground state energy
of the non-relativistic two-electron atom. Several different sets of basis
functions were systematically explored, starting with the original scheme of
Hylleraas. The most rapid convergence is found with a combination of negative
powers and a logarithm of the coordinate s = r_{1}+ r_{2}. At N=3091 terms we
pass the previous best calculation (Korobov's 25 decimal accuracy with N=5200
terms) and we stop at N=10257 with E = -2.90372 43770 34119 59831 11592 45194
40444 ...
  Previous mathematical analysis sought to link the convergence rate of such
calculations to specific analytic properties of the functions involved. The
application of that theory to this new experimental data leaves a rather
frustrating situation, where we seem able to do little more than invoke vague
concepts, such as ``flexibility.'' We conclude that theoretical understanding
here lags well behind the power of available computing machinery.


title: Side-slipping of a radiating particle

abstract:
  Radiation reaction is revisited, first in a new classical aproach, where the
physical particle 4-momentum is redefined as the energy-momentum flux across
the future light cone and is not parallel to the 4-velocity. Then in a
semi-classical approach, it is shown that, when emitting a photon, the particle
"side-slips" transversaly to its initial momentum, justifying the
non-colinearity between momentum and mean velocity. Side-slipping is finally
checked in a pure quantum mechanical treatment of synchrotron radiation.


title:
Husimi functions at dielectric interfaces: Inside-outside duality for
  optical systems and beyond

abstract:
  We introduce generalized Husimi functions at the interfaces of dielectric
systems. Four different functions can be defined, corresponding to the incident
and departing wave on both sides of the interface. These functions allow to
identify mechanisms of wave confinement and escape directions in optical
microresonators, and give insight into the structure of resonance wave
functions. Off resonance, where systematic interference can be neglected, the
Husimi functions are related by Snell's law and Fresnel's coefficients.


title:
Dynamics of a magnetic monopole in matter, Maxwell equations in dyonic
  matter and detection of electric dipole moments

abstract:
  For a monopole, the analogue of the Lorentz equation in matter is shown to be
f = g (H - v cross D). Dual-symmetric Maxwell equations, for matter containing
hidden magnetic charges in addition to electric ones, are given. They apply as
well to ordinary matter if the particles possess T-violating electric dipole
moments. Two schemes of experiments for the detection of such moments in
macroscopic pieces of matter are proposed.


title:
New developments of photodetectors for the Lake Baikal Neutrino
  Experiment

abstract:
  New developments of photodetectors for the lake Baikal neutrino experiment
are described. Some test results of photodetectors at the lake Baikal are
presented.


title: Improvement of experimental data via consistency conditions

abstract:
  Interdependencies between experimental spectra, representing line or plane
projections of electronic densities, are derived from their consistency and
symmetry conditions. Some additional relations for plane projections are
obtained by treating them as line projections of line projections.
  The knowledge of these dependencies can be utilised both for an improvement
of experimental data and for a verification of various techniques used for
correcting e.g. two-dimensional (or one-dimensional) angular correlation of
annihilation radiation spectra and Compton scattering profiles.


title:
A computational theory for the classification of natural biosonar
  targets based on a spike code

abstract:
  A computational theory for classification of natural biosonar targets is
developed based on the properties of an example stimulus ensemble. An extensive
set of echoes (84 800) from four different foliages was transcribed into a
spike code using a parsimonious model (linear filtering, half-wave
rectification, thresholding). The spike code is assumed to consist of time
differences (interspike intervals) between threshold crossings. Among the
elementary interspike intervals flanked by exceedances of adjacent thresholds,
a few intervals triggered by disjoint half-cycles of the carrier oscillation
stand out in terms of resolvability, visibility across resolution scales and a
simple stochastic structure (uncorrelatedness). They are therefore argued to be
a stochastic analogue to edges in vision. A three-dimensional feature vector
representing these interspike intervals sustained a reliable target
classification performance (0.06% classification error) in a sequential
probability ratio test, which models sequential processing of echo trains by
biological sonar systems. The dimensions of the representation are the first
moments of duration and amplitude location of these interspike intervals as
well as their number. All three quantities are readily reconciled with known
principles of neural signal representation, since they correspond to the center
of gravity of excitation on a neural map and the total amount of excitation.


title:
Spectral response of Cantor multilayers made of materials with negative
  refractive index

abstract:
  Whereas Cantor multilayers made of an isotropic dielectric-magnetic material
with positive refractive index will show power-law characteristics, low-order
Cantor multilayers made of materials with negative refractive index will not
exhibit the power-law nature. A reason for this anomalous behavior is
presented.


title:
Field-dependent surface impedance tensor in amorphous wires with two
  types of magnetic anisotropy: helical and circumferential

abstract:
  This paper concerns the theoretical and experimental investigation of the
magneto-impedance (MI) effect in amorphous wires in terms of the surface
impedance tensor. Physical concepts of MI and problems of significant practical
importance are discussed using the results obtained. The theoretical analysis
is based on employing the asymptotic-series expansion method of solving the
Maxwell equations for a ferromagnetic wire with an ac permeability tensor of a
general form associated with magnetisation rotation. The magnetic
structure-dependent impedance tensor is calculated for any frequency and
external magnetic field, and is not restricted to the case when only strong
skin-effect is present. This approach allows us to develop a rigorous
quantitative analysis of MI characteristics in wires, depending on the type of
magnetic anisotropy, the magnitude of dc bias current, and an excitation
method. The theoretical model has been tested by comparing the obtained results
with experiment. For the sake of an adequate comparison, the full impedance
tensor is measured in CoFeSiB and CoSiB amorphous wires having a
circumferential and helical anisotropy, respectively, by determining the S21
parameter. In cases, when the rotational dynamics is responsible for the
impedance behaviour, there is a reasonable agreement between the experimental
and theoretical results. Such effects as the ac biased asymmetrical MI in wires
with a circumferential anisotropy, the transformation in MI behaviour caused by
a dc current (from that having a symmetric hysteresis to an asymmetric
anhysteretic one) in wires with a helical anisotropy are discussed.


title: Approximations in description of depletion zones in nucleation kinetics

abstract:
  Different approximations to describe nucleation kinetics have been analyzed.
Some new approximations for solution of diffusion problem are proposed. Error
of the approximation with constant radius of an embryo is clarified. The theory
is illustrated by numerical calculations.


title: Time Evolution of SU(1,1) coherent states

abstract:
  Mathematical aspects of the SU(1,1) group parameter x dynamics governed by
Hamiltonians exhibiting some special types of time dependence has been
presented on an elementary level from the point of view of Moebius
transformation of complex plane. The trajectories of x in continuous and
mappings in discrete dynamics are considered. Some simple examples have been
examined. Analytical considerations and numerical results have been given.


title:
Systematic Finite-Sampling Inaccuracy in Free Energy Differences and
  Other Nonlinear Quantities

abstract:
  Systematic inaccuracy is inherent in any computational estimate of a
non-linear average, such as the free energy difference (Delta-F) between two
states or systems, because of the availability of only a finite number of data
values, N. In previous work, we outlined the fundamental statistical
description of this ``finite-sampling error.'' We now give a more complete
presentation of (i) rigorous general bounds on the free energy and other
nonlinear averages, which underscore the universality of the phenomenon; (ii)
asymptotic N->infinity expansions of the average behavior of the
finite-sampling error in Delta-F estimates; (iii) illustrative examples of
large-N behavior, both in free-energy and other calculations; and (iv) the
universal, large-N relation between the average finite-sampling error and the
fluctuation in the error. An explicit role is played by Levy and Gaussian
limiting distributions.


title:
Stationary Solutions of the Electromagnetic TE Waves Propagating along a
  Single Interface between the Two Kerr-Type Nonlinear Media

abstract:
  Propagation of the TE electromagnetic waves in self-focusing medium is
governed by the nonlinear Schroedinger equation. In this paper the stationary
solutions of this equation have been systematically presented. The phase-plane
method, qualitative analysis, and mechanical interpretation of the differential
equations are widely used. It is well known that TE waves can be guided by the
single interface between two semi-infinite media, providing that one of the
media has a self-focusing (Kerr type) nonlinearity. This special solution is
called a spatial soliton. In this paper our interests are not restricted to the
soliton solutions. In the context of the nonlinear substrate and cladding we
have found solutions which could be useful to describe also the incident light
in nonlinear medium. This result is the main point of the paper. Some of the
presented stationary solutions were already used in similar optical context in
literature but we show a little wider class of solutions. In the last section
we review and illustrate some results concerning the spatial soliton solution.


title: Study of ion feedback in multi-GEM structures

abstract:
  We study the feedback of positive ions in triple and quadruple Gas Electron
Multiplier (GEM) detectors. The effects of GEM hole diameter, detector gain,
applied voltages, number of GEMs and other parameters on ion feedback are
investigated in detail. In particular, it was found that the ion feedback is
independent of the gas mixture and the pressure. In the optimized multi-GEM
structure, the ion feedback current can be suppressed down to 0.5% of the anode
current, at a drift field of 0.1 kV/cm and gain of 10^4. A simple model of ion
feedback in multi-GEM structures is suggested. The results obtained are
relevant to the performance of time projection chambers and gas
photomultipliers.


title: Bunch coherence in parametric X-ray radiation

abstract:
  The amplitude of Parametric X-ray radiation emitted coherently by a bunch of
electrons crossing a crystal (CPXR) is calculated. When the bunch density is
modulated with a longitudinal period close to the X-ray wavelenght,
constructive many-electron interferences enhance the intensity by Nb *
|F(K)|^2, where Nb is the number of electrons in the bunch, F(K) the bunch form
factor and K a specified wave vector. CPXR can be used to test the
microbunching in a X-ray free-electron laser.


title: Power-Law Persistence in the Atmosphere: Analysis and Applications

abstract:
  We review recent results on the appearance of long-term persistence in
climatic records and their relevance for the evaluation of global climate
models and rare events.The persistence can be characterized, for example, by
the correlation C(s) of temperature variations separated by s days.We show
that, contrary to previous expectations, C(s) decays for large s as a power
law, C(s) ~ s^(-gamma). For continental stations, the exponent gamma is always
close to 0.7, while for stations on islands gamma is around 0.4. In contrast to
the temperature fluctuations, the fluctuations of the rainfall usually cannot
be characterized by long-term power-law correlations but rather by pronounced
short-term correlations. The universal persistence law for the temperature
fluctuations on continental stations represents an ideal (and uncomfortable)
test-bed for the state of-the-art global climate models and allows us to
evaluate their performance. In addition, the presence of long-term correlations
leads to a novel approach for evaluating the statistics of rare events.


title: Paradoxes of Thermal Expansion

abstract:
  It is shown that the dependence of negative thermal expansion coefficient of
many substances on the temperature contradicts to an important thermodynamic
relation. It is supposed that there are oscillations at the Cp(T) and alpha(T)
curves at alpha>0 and they are in reverse phases.


title: Scaling of solar wind epsilon and the AU, AL and AE indices

abstract:
  We apply the finite size scaling technique to quantify the statistical
properties of fluctuations in AU, AL and AE indices and in the epsilon
parameter that represents energy input from the solar wind into the
magnetosphere. We find that the exponents needed to rescale the probability
density functions (PDF) of the fluctuations are the same to within experimental
error for all four quantities. This self-similarity persists for time scales up
to ~4 hours for AU, AL and epsilon and up to ~2 hours for AE. Fluctuations on
shorter time scales than these are found to have similar long-tailed
(leptokurtic) PDF, consistent with an underlying turbulent process. These
quantitative and model-independent results place important constraints on
models for the coupled solar wind-magnetosphere system.


title:
A simulation study of the dynamics of a driven filament in an
  Aristotelian fluid

abstract:
  We describe a method, based on techniques used in molecular dynamics, for
simulating the inertialess dynamics of an elastic filament immersed in a fluid.
The model is used to study the "one-armed swimmer". That is, a flexible
appendage externally perturbed at one extremity. For small amplitude motion our
simulations confirm theoretical predictions that, for a filament of given
length and stiffness, there is a driving frequency that is optimal for both
speed and efficiency. However, we find that to calculate absolute values of the
swimming speed we need to slightly modify existing theoretical approaches. For
the more realistic case of large amplitude motion we find that while the basic
picture remains the same, the dependence of the swimming speed on both
frequency and amplitude is substantially modified. For realistic amplitudes we
show that the one armed swimmer is comparatively neither inefficient nor slow.
This begs the question, why are there little or no one armed swimmers in
nature?


title: Contributions to the theory of a two-scale homogeneous dynamo experiment

abstract:
  The principle of the Karlsruhe dynamo experiment is closely related to that
of the Roberts dynamo working with a simple fluid flow which is, with respect
to proper Cartesian co-ordinates x, y and z, periodic in x and y and
independent of z. A modified Roberts dynamo problem is considered with a flow
more similar to that in the experimental device. Solutions are calculated
numerically, and on this basis an estimate of the excitation condition of the
experimental dynamo is given. The modified Roberts dynamo problem is also
considered in the framework of the mean-field dynamo theory, in which the
crucial induction effect of the fluid motion is an anisotropic alpha-effect.
Numerical results are given for the dependence of the mean-field coefficients
on the fluid flow rates. The excitation condition of the dynamo is also
discussed within this framework. The behavior of the dynamo in the nonlinear
regime, i.e. with backreaction of the magnetic field on the fluid flow, depends
on the effect of the Lorentz force on the flow rates. The quantities
determining this effect are calculated numerically. The results for the
mean-field coefficients and the quantities describing the backreaction provide
corrections to earlier results, which were obtained under simplifying
assumptions.

categories: physics.plasm-ph astro-ph physics.flu-dyn physics.geo-ph


title:
Laser gas-discharge absorption measurements of the ratio of two
  transition rates in argon

abstract:
  The ratio of two line strengths at 922.7 nm and 978.7 nm of argon is measured
in an argon pulsed discharge with the use of a single-mode Ti:Sapphire laser.
The result 3.29(0.13) is in agreement with our theoretical prediction 3.23 and
with a less accurate ratio 2.89(0.43) from the NIST database.


title: Toward a Universal Model of Damping--Modified Coulomb Friction

abstract:
  A modification of Coulomb's law of friction uses a variable coefficient of
friction that depends on a power law in the energy of mechanical oscillation.
Through the use of three different exponents: 0, 1/2 and 1; all commonly
encountered non-viscous forms of damping are accommodated. The nonlinear model
appears to yield good agreement with experiment in cases of surface, internal,
and amplitude dependent damping.


title: Zonal Flows and Electromagnetic Drift Wave Turbulence

abstract:
  Detailed computations of tokamak edge turbulence in three dimensional,
globally consistent flux tube geometry show an inhibition of the standard
scenario in which zonal ExB flows generated by the turbulence should lead to
transport barrier formation. It is found by comparison to slab geometry and by
analysis of the energetics that the zonal flow energy is depleted by toroidal
coupling to the pressure through the geodesic curvature. Edge transport
barriers would then depend on the physics of the neoclassical equilibrium.


title:
The influence of initial impurities and irradiation conditions on defect
  production and annealing in silicon for particle detectors

abstract:
  Silicon detectors in particle physics experiments at the new accelerators or
in space missions for physics goals will be exposed to extreme radiation
conditions. The principal obstacles to long-term operation in these
environments are the changes in detector parameters, consequence of the
modifications in material properties after irradiation. The phenomenological
model developed in the present paper is able to explain quantitatively, without
free parameters, the production of primary defects in silicon after particle
irradiation and their evolution toward equilibrium, for a large range of
generation rates of primary defects. Vacancy-interstitial annihilation,
interstitial migration to sinks, divacancy and vacancy-impurity complex (VP,
VO, V2O, CiOi and CiCs) formation are taken into account. The effects of
different initial impurity concentrations of phosphorus, oxygen and carbon, as
well as of irradiation conditions are systematically studied. The correlation
between the rate of defect production, the temperature and the time evolution
of defect concentrations is also investigated.


title: Experimental Study For The Feasibility Of A Crystalline Undulator

abstract:
  We present an idea for creation of a crystalline undulator and report its
first realization. One face of a silicon crystal was given periodic
micro-scratches (trenches) by means of a diamond blade. The X-ray tests of the
crystal deformation due to given periodic pattern of surface scratches have
shown that a sinusoidal shape is observed on both the scratched surface and the
opposite (unscratched) face of the crystal, that is, a periodic sinusoidal
deformation goes through the bulk of the crystal. This opens up the possibility
for experiments with high-energy particles channeled in crystalline undulator,
a novel compact source of radiation.


title: Information Optimization in Coupled Audio-Visual Cortical Maps

abstract:
  Barn owls hunt in the dark by using cues from both sight and sound to locate
their prey. This task is facilitated by topographic maps of the external space
formed by neurons (e.g., in the optic tectum) that respond to visual or aural
signals from a specific direction. Plasticity of these maps has been studied in
owls forced to wear prismatic spectacles that shift their visual field.
Adaptive behavior in young owls is accompanied by a compensating shift in the
response of (mapped) neurons to auditory signals. We model the receptive fields
of such neurons by linear filters that sample correlated audio-visual signals,
and search for filters that maximize the gathered information, while subject to
the costs of rewiring neurons. Assuming a higher fidelity of visual
information, we find that the corresponding receptive fields are robust and
unchanged by artificial shifts. The shape of the aural receptive field,
however, is controlled by correlations between sight and sound. In response to
prismatic glasses, the aural receptive fields shift in the compensating
direction, although their shape is modified due to the costs of rewiring.


title:
Competition among molecular fragmentation channels described with
  Siegert channel pseudostates

abstract:
  To describe multiple interacting fragmentation continua, we develop a method
in which the vibrational channel functions obey outgoing wave Siegert boundary
conditions. This paper demonstrates the utility of the Siegert approach, which
uses channel energy eigenvalues that possess a negative imaginary part. The
electron scattering energy in each such channel is rotated upward, giving it an
equal and opposite imaginary part. This permits a natural inclusion of
vibrational continua without requiring them to appear as explicit channels in
the scattering matrix. Calculations illustrate the application of this theory
to photoionization, photodissociation, and dissociative recombination.


title: Feshbach Resonance Cooling of Trapped Atom Pairs

abstract:
  Spectroscopic studies of few-body systems at ultracold temperatures provide
valuable information that often cannot be extracted in a hot environment.
Considering a pair of atoms, we propose a cooling mechanism that makes use of a
scattering Feshbach resonance. Application of a series of time-dependent
magnetic field ramps results in the situation in which either zero, one, or two
atoms remain trapped. If two atoms remain in the trap after the field ramps are
completed, then they have been cooled. Application of the proposed cooling
mechanism to optical traps or lattices is considered.


title: Stability of Rossby waves in the beta-plane approximation

abstract:
  Floquet theory is used to describe the unstable spectrum at large scales of
the beta-plane equation linearized about Rossby waves. Base flows consisting of
one to three Rossby wave are considered analytically using continued fractions
and the method of multiple scales, while base flow with more than three Rossby
waves are studied numerically. It is demonstrated that the mechanism for
instability changes from inflectional to triad resonance at an O(1) transition
Rhines number Rh, independent of the Reynolds number. For a single Rossby wave
base flow, the critical Reynolds number Re^c for instability is found in
various limits. In the limits Rh --> infinity and k --> 0, the classical value
Re^c = sqrt(2) is recovered. For Rh --> 0 and all orientations of the Rossby
wave except zonal and meridional, the base flow is unstable for all Reynolds
numbers; a zonal Rossby wave is stable, while a meridional Rossby wave has
critical Reynolds number Re^c = sqrt(2). For more isotropic base flows
consisting of many Rossby waves (up to forty), the most unstable mode is purely
zonal for 2 <= Rh < infinity and is nearly zonal for Rh = 1/2, where the
transition Rhines number is again O(1), independent of the Reynolds number and
consistent with a change in the mechanism for instability from inflectional to
triad resonance.


title:
Polarization analysis of propagating surface plasmons in a subwavelength
  hole array

abstract:
  We present angle- and polarization-resolved measurements of the optical
transmission of a subwavelength hole array. These results give a (far-field)
visualization of the corresponding (near-field) propagation of the excited
surface plasmons and allow for a simple analysis of their polarization
properties.


title: Rotational Doppler Effect

abstract:
  A monochromatic linear source of light is rotated with certain angular
frequency and when such light is analysed after reflection then a change of
frequency or wavelength may be observed depending on the location of the
observer. This change of frequency or wavelength is different from the
classical Doppler effect [1] or relativistic Doppler effect [2]. The reason
behind this shift in wavelength is that a certain time interval observed by an
observer in the rotating frame is different from that of a stationary observer.


title: Giant Magneto-Impedance and its Applications

abstract:
  The status of Giant Magneto-Impedance effect is reviewed in Wires, Ribbons
and Multilayered Soft Ferromagnetic Thin Films. After establishing the
theoretical framework for the description of the effect, and the constraints
any material should have in order to show the effect, experimental work in
Wires, Ribbons and Multilayered Thin Films is described. Existing and potential
applications of the effect in Electronics and Sensing are highlighted.


title: Bayesian analysis of magnetic island dynamics

abstract:
  We examine a first order differential equation with respect to time coming up
in the description of magnetic islands in magnetically confined plasmas. The
free parameters of this equation are obtained by employing Bayesian probability
theory. Additionally a typical Bayesian change point is solved in the process
of obtaining the data.


title: On the nature of intermittency in weakly dissipative systems

abstract:
  We propose a new perspective on the intermittency in weakly dissipative
systems. It is focused on the elementary (burst-like) event separating states
with different properties. This event is seen as a real-space-time
manifestation of an instanton connecting in an extended space-time states with
distinct topology of the idealized version of the system.


title: Self-duality of the asymptotic relaxation states of fluids and plasmas

abstract:
  The states of asymptotic relaxation of 2-dimensional fluids and plasma
present a high degree of regularity and obey to the sinh-Poisson equation. We
find that embedding the classical fluid description into a field-theoretical
framework, the same equation appears as a manifestation of the self-duality.


title:
A Wind Tunnel in Your Classroom: The Design and Implementation of a
  Portable Wind Tunnel for Use in the Science Classroom

abstract:
  This article describes a wind tunnel's ease of construction and its uses as a
visualization tool that integrates concepts at the primary and secondary
levels. An Appendix contains detailed building instructions. A web site (under
construction) will provide sample lesson plans, visualization and application
tips, animations and links to background


title: Does Corticothalamic Feedback Control Cortical Velocity Tuning?

abstract:
  The thalamus is the major gate to the cortex and its contribution to cortical
receptive field properties is well established. Cortical feedback to the
thalamus is, in turn, the anatomically dominant input to relay cells, yet its
influence on thalamic processing has been difficult to interpret. For an
understanding of complex sensory processing, detailed concepts of the
corticothalamic interplay need yet to be established. To study
corticogeniculate processing in a model, we draw on various physiological and
anatomical data concerning the intrinsic dynamics of geniculate relay neurons,
the cortical influence on relay modes, lagged and nonlagged neurons, and the
structure of visual cortical receptive fields. In extensive computer
simulations we elaborate the novel hypothesis that the visual cortex controls
via feedback the temporal response properties of geniculate relay cells in a
way that alters the tuning of cortical cells for speed.


title: How to Patch Active Plasma and Collisionless Sheath: Practical Guide

abstract:
  Most plasmas have a very thin sheath compared with the plasma dimension. This
necessitates separate calculations of the plasma and sheath. The Bohm criterion
provides the boundary condition for calculation of plasma profiles. To
calculate sheath properties a value of electric field at the plasma-sheath
interface has to be specified in addition to the Bohm criterion. The value of
the boundary electric field and robust procedure to approximately patch plasma
and collisionless sheath with a very good accuracy are reported.


title:
Restriction Conditions of Motion Equations of Non-Abelian Gauge Fields
  and Their Wave Solutions

abstract:
  Similar to introduce the Lorentz condition in the motion equation of
electromagnetic field, the restriction condition is introduced in the motion
equations of non-Ablian gauge fields so that the equations are simplified
greatly and their wave solutions are obtained. Only in this way, the Feynman
rule's use become rightful in the calculation of perturbation theory.


title: On the origin of plankton patchiness

abstract:
  Plankton is the productive base of aquatic ecosystems and plays a major role
in the global control of atmospheric carbon dioxide. Nevertheless, after
intensive study, the factors that drive its spatial distribution are still far
from being clear. The models proposed so far show very limited agreement with
actual data as many of their results are not consistent with field
observations. Here we show that fluctuations and turbulent diffusion in
standard prey-predator models are able to accurately and consistently explain
plankton field observations at mesoscales (1-100 km). This includes not only
the spatial pattern but also its temporal evolution. We explicitly elucidate
the interplay between physical and biological factors, suggesting that the form
in which small scale biotic fluctuations are transferred to larger scales may
constitute one of the key elements in determining the spatial distribution of
plankton in the sea.

categories: physics.bio-ph cond-mat physics.ao-ph q-bio.PE


title: Mechanisms of noise-resistance in genetic oscillators

abstract:
  A wide range of organisms use circadian clocks to keep internal sense of
daily time and regulate their behavior accordingly. Most of these clocks use
intracellular genetic networks based on positive and negative regulatory
elements. The integration of these "circuits" at the cellular level imposes
strong constraints on their functioning and design. Here we study a recently
proposed model [N. Barkai and S. Leibler, Nature, 403:267--268, 2000] that
incorporates just the essential elements found experimentally. We show that
this type of oscillator is driven mainly by two elements: the concentration of
a repressor protein and the dynamics of an activator protein forming an
inactive complex with the repressor. Thus the clock does not need to rely on
mRNA dynamics to oscillate, which makes it especially resistant to
fluctuations. Oscillations can be present even when the time average of the
number of mRNA molecules goes below one. Under some conditions, this oscillator
is not only resistant to but paradoxically also enhanced by the intrinsic
biochemical noise.


title: Planck Scale Phenomena

abstract:
  Though the Planck scale is encountered in Quantum SuperString Theory and
Quantum Gravity, it is the Compton scale of elementary particles which is
encountered in the physical world. An explanation for this is given in terms of
Brownian processes and the duality relation.


title: Peer review in context

abstract:
  Scientific publishing is in a transition between the old paper-bound, static
forms and the new electronic media with its interactive, dynamic possibilities.
This takes place in the context of imploding library budgets and exploding
magazine costs. The scientists as authors, reviewers and editors of scientific
journals are exposed to an increased pressure by the their administrations and
the public towards quantification, objectification and certification of
scientific achievements. The ``publication roulette'' resulting from
low-quality editorial procedures often amounts to malign censorship, which not
only is experienced as a frustration by the authors, but is also delaying and
hampering the progress of science. It also leads to a waste of funds under the
cover of pseudo-objectivity and pseudo-legitimacy of financial decisions.
Different solutions are outlined and discussed. As concerns scientific
publishing, an e-print service should be established, which, in continuation of
existing e-servers such as arxiv.org, is operated either directly by the United
Nations Educational, Scientific and Cultural Organization, or by an
international consortium. In order to become generally accepted by the
scientists, certification criteria must be provided, which would make it
possible to successfully pursue a scientific career besides the traditional
peer reviewed print publications.


title:
Generalized Finsler geometry and its Cartan connection in modification
  of special relativity

abstract:
  The generalized Finsler geometry, as well as Finsler geometry, is a
generalization of Riemann geometry. The generalized Finsler geometry can be
endowed with the Cartan connection. The generalized Finsler geometry and its
Cartan connection are, as the necessary mathematical tools, involved in our
modification of special relativity, which is made by assuming the generalized
Finslerian structures of gravity-free space and time in the usual inertial
coordinate system and combining this assumption with two fundamental
postulates, (i) the principle of relativity and (ii) the constancy of the speed
of light in all inertial frames of reference.


title: The elastic capacitor and its unusual properties

abstract:
  The 'elastic capacitor' (EC) model was first introduced in studies of lipid
bilayers (the major components of biological membranes). This electro-elastic
model accounted for the compression of a membrane under applied voltage and
allowed obtaining information about the membrane's elastic properties from the
measurements of its capacitance. Later on, ECs were used to analyze the
electrical breakdown of biological membranes. The EC model was also helpful in
studies of electric double layers in various electrified interfaces (of which
the electrode/ electrolyte interface is the most common example). This
comparatively simple model, which analysis requires only high-school physics,
has a close relationship to some real-life problems in physics, chemistry and
biology. I hope that both teachers and students will find its discussion
interesting, challenging and instructive.


title: Narrow Spectral Response of a Brillouin Amplifier transmission channel

abstract:
  We investigate the spectral response of a Brillouin amplifier in the
frequency regime within the SBS bandwidth. This is done by amplitude modulating
the pump with a low frequency, and therefore, unlike previous studies, the
spectrum of the modulated pump is, in all cases, smaller than the SBS
bandwidth. We show both theoretically and experimentally that unlike phase
modulation, which was reported in the literature, the amplitude modulation
increases the Brillouin amplifier gain, and that this effect has a very narrow
bandwidth. Only modulation frequencies that are lower than a certain cut-off
frequency increase the gain. This cut-off frequency is inversely proportional
to the fiber's length, and can therefore be arbitrarily small.


title: Spatiotemporal adaptation through corticothalamic loops: A hypothesis

abstract:
  The thalamus is the major gate to the cortex and its control over cortical
responses is well established. Cortical feedback to the thalamus is, in turn,
the anatomically dominant input to relay cells, yet its influence on thalamic
processing has been difficult to interpret. For an understanding of complex
sensory processing, detailed concepts of the corticothalamic interplay need yet
to be established. Drawing on various physiological and anatomical data, we
elaborate the novel hypothesis that the visual cortex controls the
spatiotemporal structure of cortical receptive fields via feedback to the
lateral geniculate nucleus. Furthermore, we present and analyze a model of
corticogeniculate loops that implements this control, and exhibit its ability
of object segmentation by statistical motion analysis in the visual field.


title: Monopoles and Solitons

abstract:
  In this paper, we argue that the elusive magnetic monopole arises due to the
strong magnetic effects arising from the non commutative space time structure
at small scales.If this structure is ignored and we work with Minkowski
spacetime, then the magnetic effect shows up as a monopole. This would also
explain why the monopole has eluded detection even after seventy years. We next
consider anaother area in which Solitons can be applied, viz., Bose Einstein
condensation.


title: How and in What Sense Can the Entropy Be Measured?

abstract:
  In this paper, a method of measuring the entropy is presented. Problems
related to the entropy and the heat are also discussed.


title:
Effect of non-local electron conductivity on power absorption and plasma
  density profiles in low pressure inductively coupled discharges

abstract:
  A self-consistent 1-D model was developed to study the effects of non-local
electron conductivity on power absorption and plasma density profiles in a
planar inductively coupled argon discharge at low pressures (< 10 mTorr). The
model consisted of three modules: (1) an electron energy distribution function
(EEDF) module to compute the non-Maxwellian EEDF, (2) a non-local electron
kinetics module to predict the non-local electron conductivity, RF current,
electric field and power deposition profiles in the non-uniform plasma, and (3)
a heavy species transport module to solve for the ion density and velocity
profiles as well as the metastable density. Results using the non-local
electron conductivity model were compared with predictions of a local theory
(Ohm's law), under otherwise identical conditions. The RF current, electric
field, and power deposition profiles were very different, especially at 1 mTorr
for which the effective electron mean free path was larger than the skin depth.
However, the plasma density profiles were almost identical (within 10%) for the
same total power deposition in the plasma. This result suggests that, for
computing plasma density profiles, a local conductivity model (Ohm's law), with
much reduced computational expense, may be employed even in the non-local
regime.


title: The effects of related experiments

abstract:
  The effects of the experiment itself upon the obtained results and,
especially, the influence of a large number of experiments are extensively
discussed in the literature. We show that the important factor that stands at
the basis of these effects is that the involved experiments are related and not
independent and detached from each other. This relationship takes, as shown
here, different forms for different situations and is found in entirely
different physical regimes such as the quantum and classical ones.


title:
Relativistic many-body calculations of transition rates from
  core-excited states in sodiumlike ions

abstract:
  Rates and line strengths are calculated for the 2s22p53l3l' - 2s22p63l'' and
2s2p63l3l' - 2s22p63l'' electric-dipole (E1) transitions in Na-like ions with
nuclear charges ranging from Z = 14 to 100. Relativistic many-body perturbation
theory (RMBPT), including the Breit interaction, is used to evaluate retarded
E1 matrix elements in length and velocity forms. The calculations start from a
1s22s22p6 Dirac-Fock potential. First-order RMBPT is used to obtain
intermediate coupling coefficients and second-order RMBPT is used to calculate
transition matrix elements. A detailed discussion of the various contributions
to dipole matrix elements is given for sodiumlike copper (Z = 29). Transition
energies used in the calculation of transition rates are from second-order
RMBPT. Trends of transition rates as functions of Z are shown graphically for
selected transitions.


title: Combined method using Bohmian and Quantum Phase Spase Representation

abstract:
  A combined method for analyzing quantum dynamical equations which uses the
Bohmian mechanics and the quantum phase space representation is proposed. It is
based on a presentation of the wave function in phase space in a polar form.
The combined method is very effective for comparison of classical and quantum
dynamics for polynomial potentials of order no higher than second. Application
for the harmonic oscillator and quartic double well potential is performed.
Quantum fluxes and particle energy are derived by means of the proposed method.


title:
Maximally informative dimensions: Analyzing neural responses to natural
  signals

abstract:
  We propose a method that would allow for a rigorous statistical analysis of
neural responses to natural stimuli, which are non-Gaussian and exhibit strong
correlations. We have in mind a model in which neurons are selective for a
small number of stimulus dimensions out of the high dimensional stimulus space,
but within this subspace the responses can be arbitrarily nonlinear. Existing
analysis methods are based on correlation functions between stimuli and
responses, but these methods are guaranteed to work only in the case of
Gaussian stimulus ensembles. As an alternative to correlation functions, we
maximize the mutual information between the neural responses and projections of
the stimulus onto low dimensional subspaces. The procedure can be done
iteratively by increasing the dimensionality of this subspace. Those dimensions
that allow the recovery of all of the information between spikes and the full
unprojected stimuli describe the relevant subspace. If the dimensionality of
the relevant subspace indeed is small, it becomes feasible to map out the
neuron's input-output function even under fully natural stimulus conditions.
These ideas are illustrated in simulations on model visual neurons responding
to natural scenes.


title: First in the Web, but Where are the Pieces?

abstract:
  As part of their efforts to consistently and reliably identify and preserve
the archival records of their organizations, archivists are trying to address
the issue of appraising and collecting World Wide Web documents. This paper
discusses the approach taken at the Stanford Linear Accelerator Center to
collect and preserve documentation of the first World Wide Web site in the
United States.


title:
Solving the Maxwell equations by the Chebyshev method: A one-step
  finite-difference time-domain algorithm

abstract:
  We present a one-step algorithm that solves the Maxwell equations for systems
with spatially varying permittivity and permeability by the Chebyshev method.
We demonstrate that this algorithm may be orders of magnitude more efficient
than current finite-difference time-domain algorithms.


title:
Database independent Migration of Objects into an Object-Relational
  Database

abstract:
  This paper reports on the CERN-based WISDOM project which is studying the
serialisation and deserialisation of data to/from an object database
(objectivity) and ORACLE 9i.


title: Long-living plasma formations arising from metal wires burning

abstract:
  We propose a method of generation of long-living plasma objects on the base
of low-temperature plasma with condensed dispersed phase in the form of
microscopic metal particle and investigate their main characteristics.


title: Slow relaxation in weakly open vertex-splitting rational polygons

abstract:
  The problem of splitting effects by vertex angles is discussed for
nonintegrable rational polygonal billiards. A statistical analysis of the decay
dynamics in weakly open polygons is given through the orbit survival
probability. Two distinct channels for the late-time relaxation of type
1/t^delta are established. The primary channel, associated with the universal
relaxation of ''regular'' orbits, with delta = 1, is common for both the closed
and open, chaotic and nonchaotic billiards. The secondary relaxation channel,
with delta > 1, is originated from ''irregular'' orbits and is due to the
rationality of vertices.


title:
Description of the Primary Relaxation in Supercooled Liquids Through the
  Timescale Steepness Function

abstract:
  The primary relaxation in glass forming supercooled liquids (SCLs) above the
glass transformation temperature T_g is discussed in terms of the first-order
(steepness) and the second-order (curvature) temperature derivatives of the
observed primary relaxation timescale. We report new insights into the problem
of the domain of the Vogel-Fulcher-Tamman (VFT) equation, raised by Stickel et
al. (J. Chem. Phys.,1995, 1996) and discussed by Richert and Angell (ibid.,
1998). A new ergodic-cluster Gaussian statistical approach to the problem is
given based on Onsager's thermodynamic principle. The primary relaxation is
described by the VFT equation below the crossover temperature T_c (known from
mode coupling theory (MCT)), and above T_c by an extended (VFTE) equation
obtained after accounting for cluster-size fluctuations. The timescale is
parametrized by a finite number of observable parameters such as the steepness
function m_T, the MCT slowing-down exponent gamma_c, and the VFT and VFTE
strength indices D_g and D_c. The latter are defined at T_g and T_c,
respectively, for the strongly and moderately SCL states, which show absolute
thermodynamic instability at the same VFT temperature T_0, associated with the
Kauzmann temperature. For both states the limiting cluster-size characteristics
are derived from experiment. A thermodynamic-dynamic correspondence is
established between the dynamic VFT equation and the thermodynamic Adam and
Gibbs model. The problem of the irregular SCLs, which are not consistent with
the standard VFT equation, such as salol, ortho-terphenyl, and
bis-methoxy-enyl-cyclohexane, is also discussed.


title:
Evanescent-wave trapping and evaporative cooling of an atomic gas near
  two-dimensionality

abstract:
  A dense gas of cesium atoms at the crossover to two-dimensionality is
prepared in a highly anisotropic surface trap that is realized with two
evanescent light waves. Temperatures as low as 100nK are reached with 20.000
atoms at a phase-space density close to 0.1. The lowest quantum state in the
tightly confined direction is populated by more than 60%. The system offers
intriguing prospects for future experiments on degenerate quantum gases in two
dimensions.


title: Minimization of Transverse Wakefields in the NLC Accelerator Structures

abstract:
  The progress of a multiple bunches of electrons through several thousand
accelerator structures results in a wakefield which if left unchecked will kick
successive bunches off the axis of the accelerator and can at the very least
dilute the final luminosity of the final colliding beams, or at worst can lead
to a BBU (Beam Break Up) instability. In order to damp the wakefields to
acceptable levels for travelling wave structures we detune the frequencies of
the cells and we couple out the field to four adjacent manifolds. Optimizing
the manifold-cell coupling for several hundred cells and changing the bandwidth
parameters of the distribution has in previous structures been achieved by a
process of trial and error. Here, we report on an optimized Fortran code that
has been specifically written with the aim minimizing the sum of the squares of
the RMS and standard deviation of the sum wakefield. Sparse matrix techniques
are employed to reduce the computational time required for each frequency step.
The wakefield is minimized whilst ensuring that no significant local surface
heating occurs due to slots cuts into the accelerator cells to couple out the
wakefield.


title: Effective potentials for atom-atom interaction at low temperatures

abstract:
  We discuss the concept and design of effective atom-atom potentials that
accurately describe any physical processes involving only states around the
threshold. The existence of such potentials gives hope to a quantitative, and
systematic, understanding of quantum few-atom and quantum many-atom systems at
relatively low temperatures.


title: Status of e-Print Servers

abstract:
  We make a short study of the history and evolution of scientific
publications, in order to explain the format for near-term e-Prints servers,
proposing a new scientific publication scheme via digital network, and
exploring the new dynamics of publication.


title: Instability Heating of Sympathetically-Cooled Ions in a Linear Paul Trap

abstract:
  Sympathetic laser cooling of ions stored within a linear-geometry, radio
frequency, electric-quadrupole trap has been investigated using computational
and theoretical techniques. The simulation, which allows 5 sample ions to
interact with 35 laser-cooled atomic ions, revealed an instability heating
mechanism, which can prevent ions below a certain critical mass from being
sympathetically cooled. This critical mass can however be varied by changing
the trapping field parameters thus allowing ions with a very large range of
masses to be sympathetically cooled using a single ion species. A theoretical
explanation of this instability heating mechanism is presented which predicts
that the cooling-heating boundary in trapping parameter space is a line of
constant $q_u$ (ion trap stability coefficient), a result supported by the
computational results. The threshold value of $q_u$ depends on the masses of
the interacting ions. A functional form of this dependence is given.


title: Quantum Phase Spase Representation for Double Well Potential

abstract:
  A behavior of quantum states (superposition of two lowest eigenstates,
Gaussian wave packet) in phase space is studied for one and two dimensional
double well potential. Two dimensional potential is constructed from double
well potential coupled linearly and quadratically to harmonic potential.
Quantum trajectories are compared with classical ones. Preferable tunneling
path in phase space is found. An influence of energy of initial Gaussian wave
packet and trajectory initial condition on tunneling process is analyzed..
Coupling effect on trajectories and preferable tunneling path for two
dimensional potential is studied.


title: Quenched narrow-line second- and third-stage laser cooling of 40Ca

abstract:
  We demonstrate three-dimensional (3-D) quenched narrow-line laser cooling and
trapping of 40Ca. With 5 ms of cooling time we can transfer 28 % of the atoms
from a magneto-optic trap based on the strong 423 nm cooling line to a trap
based on the narrow 657 nm clock transition (that is quenched by an
intercombination line at 552 nm), thereby reducing the atoms' temperature from
2 millikelvin to 10 microkelvin. This reduction in temperature should help
reduce the overall systematic frequency uncertainty for our Ca optical
frequency standard to < 1 Hz. Additional pulsed, quenched narrow-line
third-stage cooling in 1-D yields sub-recoil temperatures as low as 300 nK, and
makes possible the observation of high-contrast two-pulse Ramsey spectroscopic
lineshapes.


title:
Singularity-Free Electrodynamics for Point Charges and Dipoles:
  Classical Model for Electron Self-Energy and Spin

abstract:
  It is shown how point charges and point dipoles with finite self-energies can
be accomodated into classical electrodynamics. The key idea is the introduction
of constitutive relations for the electromagnetic vacuum, which actually
mirrors the physical reality of vacuum polarization. Our results reduce to
conventional electrodynamics for scales large compared to the classical
electron radius $r_0\approx 2.8\times10^{-13}$ cm. A classical simulation for a
structureless electron is proposed, with the appropriate values of mass, spin
and magnetic moment.


title:
Two-color stabilization of atomic hydrogen in circularly polarized laser
  fields

abstract:
  Dynamic stabilization of atomic hydrogen against ionization in high-frequency
single- and two-color, circularly polarized laser pulses is observed by
numerically solving the three-dimensional, time-dependent Schr\"odinger
equation. The single-color case is revisited and numerically determined
ionization rates are compared with both, exact and approximate high-frequency
Floquet rates. The position of the peaks in the photoelectron spectra can be
explained with the help of dressed initial states. In two-color laser fields of
opposite circular polarization the stabilized probability density may be shaped
in various ways. For laser frequencies $\omega_1$ and $\omega_2=n\omega_1$,
$n=2,3,...$ and sufficiently large excursion amplitudes $n+1$ distinct
probability density peaks are observed. This may be viewed as the
generalization of the well-known ``dichotomy'' in linearly polarized laser
fields, i.e, as ``trichotomy,'' ``quatrochotomy,'' ``pentachotomy'' etc. All
those observed structures and their ``hula-hoop''-like dynamics can be
understood with the help of high-frequency Floquet theory and the two-color
Kramers-Henneberger transformation. The shaping of the probability density in
the stabilization regime can be realized without additional loss in the
survival probability, as compared to the corresponding single-color results.


title: Negative Specific Heat of a Magnetically Self-Confined Plasma Torus

abstract:
  It is shown that the thermodynamic maximum entropy principle predicts
negative specific heat for a stationary magnetically self-confined
current-carrying plasma torus. Implications for the magnetic self-confinement
of fusion plasma are considered.


title: Equilibrium Distribution and Tune Shift of Beams in a Linear Collider

abstract:
  The evolution of two colliding beams in a linear accelerator can be described
by two coupled Vlasov equations. In PEP-NOTE-325 by S. Kheifets and A. W. Chao
the case without external focusing was considered. In this paper we derive the
equilibrium distribution and the tune shift in the presence of external
focusing. Motion is considered only in the vertical direction and the beams are
presumed to be one-dimensional.


title:
Electronic correlation in cyclic polyenes. Behavior of approximate
  coupled-pair theories for large rings

abstract:
  We investigate the cyclic polyenes (annulenes) C_{M}H_{M}, described by the
Pariser--Parr--Pople (PPP) model, by means of the approximate coupled-pair
theories (ACP, ACPQ). For the systems with the spectroscopic value of the PPP
resonance integral beta=2.5 eV, the ACP method breaks down for M >= 446, and
the ACPQ method--for M>194. In the ACPQ method, for M>170, two close lying
solutions have been observed that become quasi-degenerate for M >= 198. The
results indicate that the ACP and ACPQ methods cannot be applied to the
one-dimensional metallic case.


title:
Multiple solutions of coupled-cluster equations for PPP model of
  [10]annulene

abstract:
  Multiple (real) solutions of the CC equations (corresponding to the CCD, ACP
and ACPQ methods) are studied for the PPP model of [10]annulene, C_{10}H_{10}.
The long-range electrostatic interactions are represented either by the
Mataga--Nishimoto potential, or Pople's R^{-1} potential. The multiple
solutions are obtained in a quasi-random manner, by generating a pool of
starting amplitudes and applying a standard CC iterative procedure combined
with Pulay's DIIS method. Several unexpected features of these solutions are
uncovered, including the switching between two CCD solutions when moving
between the weakly and strongly correlated regime of the PPP model with Pople's
potential.