title: Directed network modules

abstract:
  A search technique locating network modules, i.e., internally densely
connected groups of nodes in directed networks is introduced by extending the
Clique Percolation Method originally proposed for undirected networks. After
giving a suitable definition for directed modules we investigate their
percolation transition in the Erdos-Renyi graph both analytically and
numerically. We also analyse four real-world directed networks, including
Google's own webpages, an email network, a word association graph and the
transcriptional regulatory network of the yeast Saccharomyces cerevisiae. The
obtained directed modules are validated by additional information available for
the nodes. We find that directed modules of real-world graphs inherently
overlap and the investigated networks can be classified into two major groups
in terms of the overlaps between the modules. Accordingly, in the
word-association network and among Google's webpages the overlaps are likely to
contain in-hubs, whereas the modules in the email and transcriptional
regulatory networks tend to overlap via out-hubs.

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


title: Afterslip and aftershocks in the rate-and-state friction law

abstract:
  We study how a stress perturbation generated by a mainshock affects a
population of faults obeying a rate-state friction law. Depending on the model
parameters and on the initial state, the fault exhibits aftershocks, slow
earthquakes, or decaying afterslip. We found several regimes with slip rate
decaying as a power-law of time, with different characteristic times and
exponents. The complexity of the model makes it unrealistic to invert for the
friction law parameters from afterslip data. We modeled afterslip measurements
for the Southern California Superstition Hills earthquake using the complete
rate-and-state law, and found a huge variety of model parameters that can fit
the observed data. In particular, it is impossible to distinguish the stable
velocity strengthening regime (A>B) from the (potentially) unstable velocity
weakening regime (B>A and stiffness k<kc). Therefore, it is not necessary to
involve small scale spatial or temporal fluctuations of friction parameters A
or B in order to explain the transition between stable sliding and seismic
slip. In addition to B/A and stiffness k/kc, the fault behavior is strongly
controlled by stress levels following an event. Stress heterogeneity can thus
explain most of the variety of postseismic behavior observed in nature.
Afterslip will induce a progressive reloading of faults that are not slipping,
which can trigger aftershocks. Using the relation between stress and seismicity
derived from the rate-and-state friction law, we estimate the aftershock rate
triggered by afterslip. Aftershock rate does not simply scale with stress rate,
but exhibits a different characteristic time and power-law exponent.


title: New universality class for step bunching in the "C+ - C-" model

abstract:
  We formulate a new (1+1)D step model of potentially unstable vicinal growth
that we call "C+ - C-" model and study the step bunching process in it. The
basic assumption is that the equilibrium adatom concentrations on both sides of
the step are different and this may cause destabilization of the regular step
train. We deduce equations of step motion and numerically integrate them to
obtain the step positions on a discrete time set. New dynamic phenomena are
observed during the bunching process: 1. parts of the crystal surface undergo
temporary evaporation in the course of coalescence of two bunches, the larger
being the one that "goes back", 2. the minimal interstep distance appears in
the beginning rather than in the middle of the bunch. We speculate that the
latter may serve as a diagnostic criterion for a new universality class
constructed from the time- and size-scaling exponents describing the bunching
process in the diffusion-limited regime.


title: Plasmonic atoms and plasmonic molecules

abstract:
  The proposed paradigm of plasmonic atoms and plasmonic molecules allows one
to describe and predict the strongly localized plasmonic oscillations in the
clusters of nanoparticles and some other nanostructures in uniform way.
Strongly localized plasmonic molecules near the contacting surfaces might
become the fundamental elements (by analogy with Lego bricks) for a
construction of fully integrated opto-electronic nanodevices of any complexity
and scale of integration.


title: The twisted arc model for chiral molecules

abstract:
  We present a simple model for chiral molecules which yields the
frequency-dependent multipole-multipole polarizabilities required for
calculating the dispersive van der Waals constants in a simple, closed, and
consistent form. The model consists of a single effective charge confined to a
one-dimensional wire formed by two circular arcs, which are twisted with
respect to each other by an angle characterizing the chirality. The resulting
polarizabilities show a simple functional dependence on the model parameters,
and they serve to mimic the chiral properties of small molecules, such as H2S2,
in a reasonably realistic way.


title: Detectors for particle identification

abstract:
  The paper reviews recent progress in particle identification methods. A
survey of motivations and requirements for particle identification in various
experimental environments is followed by the main emphasis, which is on the
recent development of Cherenkov counters, from upgrades of existing devices to
a novel focusing radiator concept and new photon detectors. The impact of
including a precise measurement of the time of arrival of Cherenkov photons to
increase the kinematical region over which particle identification can be
performed is discussed. The progress in dedicated time-of-flight counters with
recently developed very fast single photon detectors is also evaluated.


title:
Comment on "How the potentials in different gauges yield the same
  retarded electric and magnetic fields," by J. A. Heras [Am. J. Phys. 75, 176
  (2007)]

abstract:
  Heras purports to show without solving the requisite dynamic equations how
the non-causal term generated by the scalar potential of the Coulomb,
Kirchhoff, or velocity gauge is canceled by an equal and opposite term in the
contribution to the electric field that is generated by the vector potential.
Heras's procedure is criticized as being just an algebraic manipulation that
has no explanatory content.


title:
Statistics of random lasing modes and amplified spontaneous emission
  spikes in weakly scattering systems

abstract:
  We have measured the spectral correlations and intensity statistics of random
lasing modes in weakly scattering systems, and compared them to those of the
amplified spontaneous emission spikes. Their dramatic differences revealed the
distinct physical mechanisms. We find that local excitation of a weakly
scattering system may greatly reduce the number of lasing modes even without
absorption outside the pumped region. The lasing modes can be very different
from the quasimodes of the passive system due to selective amplification of the
feedback from the scatterers within the local gain region.


title: General multistate models for agents with internal bias

abstract:
  We present a model of interpersonal comparisons appearing as a generalization
of a multi-state model for elements with internal bias. Within this model
agents suffering under dissatisfaction compare them with their neighbors. The
internal bias are the pre-formed preferences, and the states are represented by
the visual contacts that an agent makes to the baskets of her/his neighbors.
The topology of the comparisons is a random network. We compare the behavior
between altruistic and non-altruistic agents and we find out that altruistic
behavior alters the robustness of the network.


title: Memory distribution in complex fitness landscapes

abstract:
  In a co-evolutionary context, the survive probability of individual elements
of a system depends on their relation with their neighbors. The natural
selection process depends on the whole population, which is determined by local
events between individuals. Particular characteristics assigned to each
individual, as larger memory, usually improve the individual fitness, but an
agent possess also endogenous characteristics that induce to re-evaluate her
fitness landscape and choose the best-suited kind of interaction, inducing a
non absolute value of the outcomes of the interaction. In this work, a novel
model with agents combining memory and rational choice is introduced, where
individual choices in a complex fitness landscape induce changes in the
distribution of the number of agents as a function of the time. In particular,
the tail of this distribution is fat compared with distributions for agents
interacting only with memory.


title:
Comment on "Resonant multi-photon IR dissociation spectroscopy of a
  trapped and sympathetically cooled biomolecular ion species"

abstract:
  In the e-print arXiv:1110.2774 the authors study the infrared multiple-photon
induced dissociation (IRMPD) of cooled polyatomic ion species. Here we propose
a physical explanation of the obtained experimental results and its simple
experimental test.


title: Passenger life-saving in a badly damaged aircraft scenario

abstract:
  Offered is a new method for saving passenger lives in any catastrofic
situation, including total failure of aircraft control, extreme damage and loss
aircraft wings, tail, breakdown all propelling engines, etc. It shown here that
previous works which have proposed using only parachutes are useless because
their proposers failed to consider the likely overload of the parachute jerk
stress (at the moment of parachute release) and the impact of aircraft on Earth
surface. These jeck and impact destroy aircraft and kill passengers.
  Offered is a connected series of related technical innovations which overcome
these obvious difficalties and allow for a soft, near zero speed landing in any
topographically suitable place, allowing potential to save aircraft. This
method may be applied to all existing airplanes and increases their weight only
about 1.5 - 2.5%. Also, the method may be used for vertically landing the
already built aircraft, for example, when any runway is damaged or would become
overloaded.


title: Plasma: the genesis of the word

abstract:
  The historical roots of the word plasma are recalled. It is suggested that
possibly at the beginning of the researches in low-pressure gas discharges the
driving motivation was related to the psychic phenomena investigated by Sir
William Crookes.


title: Optimal transport on wireless networks

abstract:
  We present a study of the application of a variant of a recently introduced
heuristic algorithm for the optimization of transport routes on complex
networks to the problem of finding the optimal routes of communication between
nodes on wireless networks. Our algorithm iteratively balances network traffic
by minimizing the maximum node betweenness on the network. The variant we
consider specifically accounts for the broadcast restrictions imposed by
wireless communication by using a different betweenness measure. We compare the
performance of our algorithm to two other known algorithms and find that our
algorithm achieves the highest transport capacity both for minimum node degree
geometric networks, which are directed geometric networks that model wireless
communication networks, and for configuration model networks that are
uncorrelated scale-free networks.


title: A mechanism for oscillatory instability in viscoelastic cross-slot flow

abstract:
  Interior stagnation point flows of viscoelastic liquids arise in a wide
variety of applications including extensional viscometry, polymer processing
and microfluidics. Experimentally, these flows have long been known to exhibit
instabilities, but the mechanisms underlying them have not previously been
elucidated. We computationally demonstrate the existence of a supercritical
oscillatory instability of low-Reynolds number viscoelastic flow in a
two-dimensional cross-slot geometry. The fluctuations are closely associated
with the "birefringent strand" of highly stretched polymer chains associated
with the outflow from the stagnation point at high Weissenberg number.
Additionally, we describe the mechanism of instability, which arises from the
coupling of flow with extensional stresses and their steep gradients in the
stagnation point region.


title: Density dependence of the forbidden lines in Ni-like tungsten

abstract:
  The magnetic-octupole (M3) and electric-quadrupole (E2) transitions between
the ground state $3d^{10} ^1S_0$ and the lowest excited $3d^94s$ $(5/2,1/2)$ J
= 3 and J = 2 states in the Ni-like tungsten are shown to exhibit a strong
dependence on electron density $N_e$ in the range of values typical for tokamak
plasmas. Remarkably, the total intensity of these overlapping lines remains
almost constant, which may explain the strong emission in the 7.93 \AA line
observed in tokamak experiments (Neu R et al. 1997 J Phys B {\bf 30} 5057).
Utilization of the M3 and E2 line ratios for density diagnostics in
high-spectral-resolution experiments is discussed as well.


title: Holophotography with a diffraction grating

abstract:
  Color encoding of depth is shown to occur naturally in images of objects
observed through diffraction gratings under common white light illumination. A
synthetic image is then obtained from a single point of view, a phenomenon that
can be applied to stereophotography. The image can be recorded in a common
color photograph, providing a simple method of visual decoding by means of
ordinary colored 3D spectacles. The fundamental equation and the photographic
procedure for maximum fidelity in three-dimensional reproduction are described.
The result is a photograph that has the capability of registering all the views
of an object in a continuous sequence, which is called holophotography and was
previously obtained by means of a hologram. By eliminating the need for a laser
and holographic film, a new technique for holography in white light is
foreseen.


title:
Evaporation and growth of crystals - propagation of step density
  compression waves at vicinal surfaces

abstract:
  We studied the step dynamics during crystal sublimation and growth in the
limit of fast surface diffusion and slow kinetics of atom attachment-detachment
at the steps. For this limit we formulate a model free of the quasi-static
approximation in the calculation of the adatom concentration on the terraces at
the crystal surface. Such a model provides a relatively simple way to study the
linear stability of a step train in a presence of step-step repulsion and an
absence of destabilizing factors (as Schwoebel effect, surface electromigration
etc.). The central result is that a critical velocity of the steps in the train
exists which separates the stability and instability regimes. When the step
velocity exceeds its critical value the plot of these trajectories manifests
clear space and time periodicity (step density compression waves propagate on
the vicinal surface). This ordered motion of the steps is preceded by a
relatively short transition period of disordered step dynamics.


title: Coexistence of opposite opinions in a network with communities

abstract:
  The Majority Rule is applied to a topology that consists of two coupled
random networks, thereby mimicking the modular structure observed in social
networks. We calculate analytically the asymptotic behaviour of the model and
derive a phase diagram that depends on the frequency of random opinion flips
and on the inter-connectivity between the two communities. It is shown that
three regimes may take place: a disordered regime, where no collective
phenomena takes place; a symmetric regime, where the nodes in both communities
reach the same average opinion; an asymmetric regime, where the nodes in each
community reach an opposite average opinion. The transition from the asymmetric
regime to the symmetric regime is shown to be discontinuous.


title:
High activity of He droplets following ionization of systems inside
  those droplets

abstract:
  Relaxation processes following inner-valence ionization of a system can be
modified dramatically by embedding this system in a suitable environment.
Surprisingly, such an environment can be even composed of helium atoms, the
most inert species available. As demonstrated by the examples of Ne and Ca
atoms embedded in He droplets, a fast relaxation process [Interatomic Coulombic
Decay (ICD)] takes place merely due to the presence of the He surroundings. We
have computed ICD widths for both 4He_N and 3He_N droplets doped with Ne and Ca
and discuss the findings in some detail. In the case of Ne, ICD is by far the
dominating relaxation pathway. In Ca, atomic Auger decay is also possible but
ICD becomes a competitive relaxation pathway in the droplets.


title: The Galam Model of Minority Opinion Spreading and the Marriage Gap

abstract:
  In 2002, Serge Galam designed a model of a minority opinion spreading. The
effect is expected to lead a conservative minority to prevail if the issue is
discussed long enough. Here we analyze the marriage gap, i.e. the difference in
voting for Bush and Kerry in 2004 between married and unmarried people. It
seems possible to interpret this marriage gap in terms of the Galam model.


title: Analysis of ray phase-space recirculation in an extended Budden problem

abstract:
  A three-wave Budden model with two resonance layers is constructed that
allows recirculation of energy fluxes along a quadrangle in ray phase space.
The transmission, reflection, and conversion coefficients for this extended
Budden problem are calculated by ray phase-space methods and the
modular-eikonal approach. Analytical and numerical results show that all
coefficients exhibit interference effects that depend on an interference phase
calculated from the coupling constants and the area enclosed by the quadrangle.


title: Nuclear spin interferences in bulk water at room temperature

abstract:
  Nuclear spin interference effects generated in a macroscopic sample of 10ml
degassed water are detected in a simple NMR experiment. A \pi/2 - \tau - \pi/2
RF double pulse sequence (Ramsey sequence) is applied to the water sample
immersed in a static magnetic field B0 " 4.7T. For a homogeneity of B0 of the
order of \Delta B0/B0 = 2 . 10^{-8}, the nuclear spin interference term is
controlled with a maximum relative deviation of 9.7 %. These results are a
first step to manipulation of nuclear spin coherence of water molecules.


title:
A Hypothesis for the Speed of Propagation of Light in electric and
  magnetic fields and the Planning of an Experiment for its Verification

abstract:
  As generally known, the speed of propagation of light in solid state bodies
can be different from the speed of light in vacuum. That the mere presence of
electric or magnetic fields in the vacuum can suffice to influence the speed of
light, is a hypothesis under discussion, which is based on considerations of
Quantumelectrodynamics.
  For a verification of this hypothesis, an interference-experiment might be
performed, of which the planning is given in this article.


title: A possible explanation of the phase diagram of cuprate superconductors

abstract:
  A d-p pairing curve that is consistent with the pseudogap curve observed in
experiments is found on a d-p model on phonon mechanism. On the discovery we
suggest that there are two pseudogaps associated with the nearly localized d-p
pairs and nearly free p-p pairs. The p-p pairs look like bosons and are
responsible for superconductivities.


title: Outline of a superunification model

abstract:
  Tensor products of standard model bosons and fermions form a spin-2
self-realization of SU(5), and because every quark can be interpreted as a
lepton that has coupled to an appropriate element of this adjoint
representation, and inversely, SUGRA GUT interactions between proposed spin-2
elements and baryons of spin 3/2, can exist as residual manifestations of
quark-lepton transitions that occur within baryonic domains of asymptotic
freedom. It is argued that these interactions preserve baryonic structure and
continually re-establish a locally SUSY version of broken SU(5), indicating a
recurring inflation event that addresses the large scale.


title: Nonlinear Simulation of Drift Wave Turbulence

abstract:
  In a two-dimensional version of the modified Hasegawa-Wakatani (HW) model,
which describes electrostatic resistive drift wave turbulence, the resistive
coupling between vorticity and density does not act on the zonal components
($k_{y}=0$). It is therefore necessary to modify the HW model to treat the
zonal components properly. The modified equations are solved numerically, and
visualization and analysis of the solutions show generation of stable zonal
flows, through conversion of turbulent kinetic energy, and the consequent
turbulence and transport suppression. It is demonstrated by comparison that the
modification is essential for generation of zonal flows.


title:
Metastable states, the adiabatic theorem and parity violating geometric
  phases I

abstract:
  A system of metastable plus unstable states is discussed. The mass matrix
governing the time development of the system is supposed to vary slowly with
time. The adiabatic limit for this case is studied and it is shown that only
the metastable states obtain the analogs of the dynamical and geometrical phase
factors familiar from stable states. Abelian and non-abelian geometric phase
factors for metastable states are defined.


title:
Metastable states, the adiabatic theorem and parity violating geometric
  phases II

abstract:
  We discuss and calculate parity conserving (PC) and parity violating (PV)
geometric phases for the metastable 2S states of hydrogen and deuterium. The
atoms are supposed to be subjected to slowly varying electric and magnetic
fields which act as external parameters for the atoms. Geometric flux density
fields are introduced which allow for an easy overview how to choose the paths
in parameter space in order to obtain only PC or only PV geometric phases. The
PV phases are calculated in the Standard Model of particle physics. Even if
numerically they come out small they have interest of principle as a new
manifestation of parity violation in atomic physics.


title:
Lessons Drawn from Implementation of Online Tutoring System in Physics
  Courses

abstract:
  The online tutoring system CAPA was implemented at Afeka College in the
academic year 2000-2001 in calculus based physics courses. It was used also in
the academic year 2001-2002 and was very successful in improving understanding
and achievements of the students. The paper describes the system features and
the case study of its implementation. Lessons drawn from use of the CAPA system
are discussed. The system no doubt contributed significantly to increased
understanding and higher achievements in the final exams. This was at a price
that students felt that they had to devote more time to study than
traditionally required. The instructor has to invest more time than
traditionally done in composing new problems and managing the system. However,
the increased interaction with the students makes the teaching process much
more interesting and rewarding.


title: Dynamic and static limitation in multiscale reaction networks, revisited

abstract:
  The concept of limiting step gives the limit simplification: the whole
network behaves as a single step. However, in its simplest form this idea is
applicable only to the simplest linear cycles in steady states. For such the
simplest cycles the nonstationary behaviour is also limited by a single step,
but not the same step that limits the stationary rate. We develop a general
theory of static and dynamic limitation for all linear multiscale networks. New
estimates of eigenvectors for diagonally dominant matrices are used.
  Multiscale ensembles of reaction networks with well separated constants are
introduced and typical properties of such systems are studied. For any given
ordering of reaction rate constants the explicit approximation of steady state,
relaxation spectrum and related eigenvectors ("modes") is presented. The
obtained multiscale approximations that we call "dominant systems" are
computationally cheap and robust. These dominant systems can be used for direct
computation of steady states and relaxation dynamics, especially when kinetic
information is incomplete, for design of experiments and mining of experimental
data, and could serve as a robust first approximation in perturbation theory or
for preconditioning.


title: Diamagnetic nature of stratified thin metals in visible range

abstract:
  It is numerically demonstrated that effectively strong diamagnetic resonance
emerges at visible frequencies in stratified metal-dielectric metamaterials.
The effective optical constants are extracted by two-complex reflectivity
method. It is clarified that the effective diamagnetic response originates from
local diamagnetism at stratified thin metals. The effective diamagnetism is
crucially sensitive to the sturucture of unitcell. The effective diamagnetic
response is always associated with effective plasma frequency and is therefore
regarded as a magnetic component of the collective excitation.


title:
Galilean relativity, special relativity and the work-kinetic energy
  theorem revisited

abstract:
  Transformation equations for the kinetic energy of the same bullet in
Galileo's and Einstein's special relativity are derived. The special relativity
result is extended to the case of a photon.


title: A global algorithm for clustering univariate observations

abstract:
  This paper deals with the clustering of univariate observations: given a set
of observations coming from $K$ possible clusters, one has to estimate the
cluster means. We propose an algorithm based on the minimization of the "KP"
criterion we introduced in a previous work. In this paper, we show that the
global minimum of this criterion can be reached by first solving a linear
system then calculating the roots of some polynomial of order $K$. The KP
global minimum provides a first raw estimate of the cluster means, and a final
clustering step enables to recover the cluster means. Our method's relevance
and superiority to the Expectation-Maximization algorithm is illustrated
through simulations of various Gaussian mixtures. \keywords{unsupervised
clustering \and non-iterative algorithm \and optimization criterion \and
univariate observations


title:
Capillary Rise in Nanopores: Molecular Dynamics Evidence for the
  Lucas-Washburn Equation

abstract:
  When a capillary is inserted into a liquid, the liquid will rapidly flow into
it. This phenomenon, well studied and understood on the macroscale, is
investigated by Molecular Dynamics simulations for coarse-grained models of
nanotubes. Both a simple Lennard-Jones fluid and a model for a polymer melt are
considered. In both cases after a transient period (of a few nanoseconds) the
meniscus rises according to a $\sqrt{\textrm{time}}$-law. For the polymer melt,
however, we find that the capillary flow exhibits a slip length $\delta$,
comparable in size with the nanotube radius $R$. We show that a consistent
description of the imbibition process in nanotubes is only possible upon
modification of the Lucas-Washburn law which takes explicitly into account the
slip length $\delta$.


title: Desperately Seeking Superstrings

abstract:
  We provide a detailed analysis of the problems and prospects of superstring
theory c. 1986, anticipating much of the progress of the decades to follow.


title:
Exact time evolution and master equations for the damped harmonic
  oscillator

abstract:
  Using the exact path integral solution for the damped harmonic oscillator it
is shown that in general there does not exist an exact dissipative Liouville
operator describing the dynamics of the oscillator for arbitrary initial bath
preparations. Exact non-stationary Liouville operators can be found only for
particular preparations. Three physically meaningful examples are examined. An
exact new master equation is derived for thermal initial conditions. Second,
the Liouville operator governing the time-evolution of equilibrium correlations
is obtained. Third, factorizing initial conditions are studied. Additionally,
one can show that there are approximate Liouville operators independent of the
initial preparation describing the long time dynamics under appropriate
conditions. The general form of these approximate master equations is derived
and the coefficients are determined for special cases of the bath spectral
density including the Ohmic, Drude and weak coupling cases. The connection with
earlier work is discussed.


title: Comment on Enhanced TKE Dissipation under Breaking Waves

abstract:
  It is noted that the results of recent experiments on the enhancement of
turbulent kinetic energy (TKE) dissipation below surface waves can be stated as
follows. TKE dissipation is enhanced by a factor $15 H_{ws}/z$ at depths $0.5
H_{ws} < z < 20 H_{ws}$ with respect to the wall-layer result $\epsilon =
u_{*w}^3/\kappa z$, where $u_{*w}$ is the friction velocity in water and
$H_{ws}$ is the significant wind-sea wave height. For open ocean conditions,
this reduces in most cases to an enhancement factor $10^6 u_{*w}^2/gz \approx
U_{10}^2/gz$.


title:
Harmonic analysis of random number generators and multiplicative groups
  of residue class rings

abstract:
  The spectral test of random number generators (R.R. Coveyou and R.D.
McPherson, 1967) is generalized. The sequence of random numbers is analyzed
explicitly not just via their n-tupel distributions. The generalized analysis
of many generators becomes possible due to a theorem on the harmonic analysis
of multiplicative groups of residue class rings. We find that the mixed
multiplicative generator with power of two modulus does not pass the extended
test with an ideal result. Best qualities has a new generator with the
recursion formula X(k+1)=a*X(k)+c*int(k/2) mod 2^d. We discuss the choice of
the parameters a, c for very large moduli 2^d and present an implementation of
the suggested generator with d=256, a=2^128+2^64+2^32+62181, c=(2^160+1)*11463.


title: Harmonic analysis of random number generators

abstract:
  The spectral test of random number generators (R.R. Coveyou and R.D.
McPherson, 1967) is generalized. The sequence of random numbers is analyzed
explicitly, not just via their n-tupel distributions. We find that the mixed
multiplicative generator with power of two modulus does not pass the extended
test with an ideal result. Best qualities has a new generator with the
recursion formula X(k+1)=a*X(k)+c*int(k/2) mod 2^d. We discuss the choice of
the parameters a, c for very large moduli 2^d and present an implementation of
the suggested generator with d=256, a=2^128+2^64+2^32+62181, c=(2^160+1)*11463.


title: Resistive Magnetohydrodynamic Equilibria in a Torus

abstract:
  It was recently demonstrated that static, resistive, magnetohydrodynamic
equilibria, in the presence of spatially-uniform electrical conductivity, do
not exist in a torus under a standard set of assumed symmetries and boundary
conditions. The difficulty, which goes away in the ``periodic straight cylinder
approximation,'' is associated with the necessarily non-vanishing character of
the curl of the Lorentz force, j x B. Here, we ask if there exists a spatial
profile of electrical conductivity that permits the existence of zero-flow,
axisymmetric r esistive equilibria in a torus, and answer the question in the
affirmative. However, the physical properties of the conductivity profile are
unusual (the conductivity cannot be constant on a magnetic surface, for
example) and whether such equilibria are to be considered physically possible
remains an open question.


title: Toroidal Vortices in Resistive Magnetohydrodynamic Equilibria

abstract:
  Resistive steady states in toroidal magnetohydrodynamics (MHD), where Ohm's
law must be taken into account, differ considerably from ideal ones. Only for
special (and probably unphysical) resistivity profiles can the Lorentz force,
in the static force-balance equation, be expressed as the gradient of a scalar
and thus cancel the gradient of a scalar pressure. In general, the Lorentz
force has a curl directed so as to generate toroidal vorticity. Here, we
calculate, for a collisional, highly viscous magnetofluid, the flows that are
required for an axisymmetric toroidal steady state, assuming uniform scalar
resistivity and viscosity. The flows originate from paired toroidal vortices
(in what might be called a ``double smoke ring'' configuration), and are
thought likely to be ubiquitous in the interior of toroidally driven
magnetofluids of this type. The existence of such vortices is conjectured to
characterize magnetofluids beyond the high-viscosity limit in which they are
readily calculable.


title: Jets from Collapsing Bubbles

abstract:
  When an asymmetric bubble collapses it generally produces a well defined high
velocity jet. This is remarkable because one might expect such a collapse to
produce a complex or chaotic flow rather than an ordered one. I present a
dimensional argument for the ubiquity of jets from collapsing bubbles, and
model the aspherical collapse of a bubble with pieces of Rayleigh's solution
for spherical collapse and its cylindrical analogue. This model explains the
ubiquity of jet formation in aspherical collapse, and predicts the shape and
velocity profile of the resulting jet. These predictions may be tested in the
laboratory or by numerical calculation. An application to solid spall is
suggested.


title: Future Colliders

abstract:
  The high energy physics advantages, disadvantages and luminosity requirements
of hadrons, of leptons and photon-photon colliders are considered. Technical
arguments for increased energy in each type of machine are presented. Their
relative size, and the implications of size on cost are discussed.


title: High Luminosity Muon Collider Design

abstract:
  Muon Colliders have unique technical and physics advantages and disadvantages
when compared with both hadrons and electron machines. They should be regarded
as complementary. Parameters are given of a 4 TeV high luminosity muon-muon
collider, and of a 0.5 TeV demonstration machine. We discuss the various
systems in such muon collider.


title: Local Interactions and Protein Folding: A 3D Off-Lattice Approach

abstract:
  The thermodynamic behavior of a three-dimensional off-lattice model for
protein folding is probed. The model has only two types of residues,
hydrophobic and hydrophilic. In absence of local interactions, native structure
formation does not occur for the temperatures considered. By including sequence
independent local interactions, which qualitatively reproduce local properties
of functional proteins, the dominance of a native state for many sequences is
observed. As in lattice model approaches, folding takes place by gradual
compactification, followed by a sequence dependent folding transition. Our
results differ from lattice approaches in that bimodal energy distributions are
not observed and that high folding temperatures are accompanied by relatively
low temperatures for the peak of the specific heat. Also, in contrast to
earlier studies using lattice models, our results convincingly demonstrate that
one does not need more than two types of residues to generate sequences with
good thermodynamic folding properties in three dimensions.


title: The Non-Organic Theory of the Genesis of Petroleum

abstract:
  Recent advances in interdisciplinary fields as diverse as astrophysics,
cosmogeophysics, nuclear geology, etc. have led to interesting developments in
the non-organic theory of the genesis of petroleum. This theory, which holds
that petroleum is of an abiogenic primordial origin, provides an explanation
for certain features of petroleum geology that are hard to explain within the
standard organic framework. If the non-organic theory is correct, then
hydrocarbon reserves would be enormous and almost inexhaustable.


title: Limited-Diffraction Solutions to Maxwell and to Schroedinger Equations

abstract:
  We have developed a new family of limited-diffraction electromagnetic
X-shaped waves based on the scalar "X waves" discovered previously. These waves
are diffraction-free in theory and particle-like (wave packets), in that they
maintain their shape as they propagate to an infinite distance. The X waves
possess (theoretically) infinitely extended arms, and --at least, the ones
studied in this paper-- have an infinite total energy: therefore, they are not
physically realizable. However, they can be truncated in both space and time
and approximated by means of a finite aperture radiator so to get a large
enough depth of interest (depth of field). In addition to the Maxwell
equations, X wave solutions to the free Schroedinger equation are also
obtained. Possible applications of these new waves are discussed. Finally, we
discuss the appearance of the X-shaped solutions from the purely geometric
point of view of the Special Relativity theory. [PACS nos. 03.40.Kf, 03.50.De,
41.20.Jb, 41.20.Bt, 42.25.Bs, 03.30.+p, 03.65.-w].


title: Life and Water

abstract:
  Many living organisms on Earth are strongly dependent on water, the natural
liquid of the planet. A possible reason for that could be the conjecture of
Ryoji Takahashi [Phys. Lett. A 141, 15 (1989)] that water microdrops release
negentropy through a phase transition to a phase with zero surface tension.
Biological cells could make use of such a phase transition in their duty cycle.
We comment on the relative merit of this conjecture, and present it in wider
theoretical context.


title: Uniqueness in Relativistic Hydrodynamics

abstract:
  The choice of the 4-velocity in the relativistic hydrodynamics proposed by
Landau and Lifshitz is demonstrated to be the only one satisfying all general
principles. Especially the far more widely adopted Eckart choice has to be
abandoned.


title: A Simplified Approach to Optimally Controlled Quantum Dynamics

abstract:
  A new formalism for the optimal control of quantum mechanical physical
observables is presented. This approach is based on an analogous classical
control technique reported previously[J. Botina, H. Rabitz and N. Rahman, J.
chem. Phys. Vol. 102, pag. 226 (1995)]. Quantum Lagrange multiplier functions
are used to preserve a chosen subset of the observable dynamics of interest. As
a result, a corresponding small set of Lagrange multipliers needs to be
calculated and they are only a function of time. This is a considerable
simplification over traditional quantum optimal control theory[S. shi and H.
Rabitz, comp. Phys. Comm. Vol. 63, pag. 71 (1991)]. The success of the new
approach is based on taking advantage of the multiplicity of solutions to
virtually any problem of quantum control to meet a physical objective. A family
of such simplified formulations is introduced and numerically tested. Results
are presented for these algorithms and compared with previous reported work on
a model problem for selective unimolecular reaction induced by an external
optical electric field.


title: Laying the ghost of the relativistic temperature transformation

abstract:
  Using the Unruh-DeWitt detector, it is shown that a universal and continuous
Lorentz transformaion of temperature cannot exist for black-body radiation.
Since any valid Lorentz transformation of temperature must be able to deal with
black-body radiation, it is concluded that a universal and continuous
temperature transformation does not exist.


title: Note on the dynamic instability of microtubules

abstract:
  If the dynamic instability of microtubules follows a gamma distribution then
one can associate to it a Cantor set


title:
Consistent analytical approach for the quasiclassical radial dipole
  matrix elements

abstract:
  A consistent analytical approach for calculation of the quasiclassical radial
dipole matrix elements in the momentum and coordinate representations is
presented. Very simple but relatively precise expressions for the matrix
elements are derived in both representations. All analytical expressions
contain only one special function -- the Anger function and its derivative.
They generalise and increase the accuracy of some known quasiclassical
expressions. The small difference between the two forms of the expressions for
the dipole matrix elements indicates to the applicability of the simple
expressions given by the consistent quasiclassical approach even for low atomic
states.


title:
A Fast Algorithm for High-Dimensional Markov Processes with Finite Sets
  of Transition Rates

abstract:
  The discrete class algorithm presented in this paper is an efficient
simulation tool for stochastic processes governed by a reasonably small set of
transition rates. The algorithm is presented, its performance compared to
prevailing methods and applications to epitaxial growth and neuronal models are
sketched.
  Source code is available from the author's WWW-site.


title: Quantum Interference in Three Photon Down Conversion

abstract:
  We study degenerate three photon down conversion as a potential scheme for
generating nonclassical states of light which exhibit clear signatures of phase
space interference. The Wigner function representing these states contains an
interference pattern manifesting quantum coherence between distinct phase space
components, and has substantial areas of negativity. We develop an analytical
description of the interference pattern, which demonstrates how the
oscillations of the Wigner function are built up by the superposition
principle. We analyze the impact of dissipation and pump fluctuations on the
visibility of the interference pattern; the results suggest that some
signatures of quantum coherence can be observed in the presence of moderate
amount of noise.


title:
On the mechanism of decadal oscillations in a coarse resolution ocean
  model

abstract:
  The mechanism that causes an interdecadal oscillation in a coarse resolution
sector ocean model forced by mixed boundary conditions is studied. The
oscillation is characterized by large fluctuations in convective activity and
air/sea heat exchange on a decadal time scale. When the convective activity is
large, a strengthening of the southeastward surface flow advects more
relatively fresh water from the northwestern part of the basin into the
convective area, which reduces the convective activity. Similarly, when the
convective activity is small, the flow of relatively fresh water is weak, which
enables the expansion of the convective area. The oscillation critically
depends on how the ocean circulation, and especially the surface circulation,
responds to anomalous convective activity. Horizontal boundaries turn out to
play an important role in the dynamical response of the ocean circulation. That
the dynamical reponse is essential to the oscillation is confirmed with two
simple (conceptual) models, and some idealized ocean experiments.


title: Phase Coexistence Properties of Polarizable Stockmayer Fluids

abstract:
  We report the phase coexistence properties of polarizable Stockmayer fluids
of reduced permanent dipoles equal to 1.0 and 2.0 and reduced polarizabilities
equal to 0.00, 0.03, and 0.06, calculated by a series of grand canonical Monte
Carlo simulations with the histogram reweighting method. In the histogram
reweighting method, the distributions of density and energy calculated in Grand
Canonical Monte Carlo simulations are stored in histograms and analyzed to
construct the grand canonical partition function of the system. All
thermodynamic properties are calculated from the grand partition function. The
results are compared with Wertheim's renormalization perturbation theory.
Deviations between theory and simulation results for the coexistence envelope
are near 2% for the lower dipole moment and 10 % for the higher dipole moment
we studied.

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


title:
Prediction of Phase Transition in CaSiO$_3$ Perovskite and Implications
  for Lower Mantle Structure

abstract:
  First principles linear response calculations are used to investigate the
lattice dynamics of what is thought to be the third most abundant phase in the
lower mantle, CaSiO_3 perovskite. The commonly assumed cubic structure (Pm3m)
is found to be dynamically unstable at all pressures, exhibiting unstable modes
along the Brillouin zone edge from the M-point to the R-point. Based on these
results, we predict that the ground state structure of CaSiO_3 perovskite is a
distorted phase with lower than cubic symmetry. We predict that a phase
transition occurs in CaSiO_3 perovskite within the earth's lower mantle from
the low temperature distorted phase to the cubic phase at high temperature. The
predicted phase transition provides a possible explanation of some of the
seismological observations of reflective features within the lower mantle.


title: Accuracy of Sampling Quantum Phase Space in Photon Counting Experiment

abstract:
  We study the accuracy of determining the phase space quasidistribution of a
single quantized light mode by a photon counting experiment. We derive an exact
analytical formula for the error of the experimental outcome. This result
provides an estimation for the experimental parameters, such as the number of
events, required to determine the quasidistribution with assumed precision. Our
analysis also shows that it is in general not possible to compensate the
imperfectness of the photodetector in a numerical processing of the
experimental data. The discussion is illustrated with Monte Carlo simulations
of the photon counting experiment for the coherent state, the one photon Fock
state, and the Schroedinger cat state.


title:
On Stern-Gerlach forces allowed by special relativity and the special
  case of the classical spinning particle of Derbenev-Kondratenko

abstract:
  This work is devoted to an examination of Stern-Gerlach forces consistent
with special relativity and is motivated by recent interest in the relativistic
Stern-Gerlach force acting on polarized protons in high-energy particle
accelerators. The equations for the orbital and spin motion of a classical
charged particle with arbitrary intrinsic magnetic dipole moment in an external
electromagnetic field are considered and by imposing the constraints of special
relativity and restricting to first order in spin (= first order $\hbar$) a
well-defined class of spin-orbit systems is obtained. All these systems can be
treated on an equal footing including such prominent cases as those considered
by Frenkel and by Good. The Frenkel case is considered in great detail because
I show that this system is identical with the one introduced by Derbenev and
Kondratenko for studying spin motion in accelerators. In particular I prove
that the spin-orbit system of Derbenev and Kondratenko is (nonmanifestly)
Poincar\'e covariant and identify the transformation properties of this system
under the Poincar\'e group. The Derbenev-Kondratenko Hamiltonian was originally
proposed as a way to combine relativistic spin precession and the Lorentz
force. The aforementioned findings now demonstrate that the
Derbenev-Kondratenko Hamiltonian also provides a legitimate framework for
handling the relativistic Stern-Gerlach force. Numerical examples based on the
Frenkel and Good cases for the HERA proton ring and electromagnetic traps are
provided.


title: An Explicit Construction of Casimir Operators and Eigenvalues:II

abstract:
  It is given a way of computing Casimir eigenvalues for Weyl orbits as well as
for irreducible representations of Lie algebras. A kappa(s) number of
polinomials which depend on rank N are obtained explicitly for A_N Casimir
operators of order s where kappa(s) is the number of partitions of s into
positive integers except 1. It is also emphasized that these eigenvalue
polinomials prove useful in obtaining formulas to calculate weight
multiplicities and in explicit calculations of the whole cohomology ring of
Classical and also Exceptional Lie algebras.


title:
Retarded long-range potentials for the alkali-metal atoms and a
  perfectly conducting wall

abstract:
  The retarded long-range potentials for hydrogen and alkali-metal atoms in
their ground states and a perfectly conducting wall are calculated. The
potentials are given over a wide range of atom-wall distances and the validity
of the approximations used is established.


title: Eight-component differential equation for leptonium

abstract:
  It is shown that the potential for lepton-antilepton bound states (leptonium)
is the Fourier transform of the first Born approximation to the QED scattering
amplitude in an 8-component equation, while 16-component equations are
excluded. The Fourier transform is exact at all cms energies $-\infty < E <
\infty$; the resulting atomic spectrum is explicitly CPT-invariant.


title:
Formation of antihydrogen atoms in an ultra-cold positron-antiproton
  plasma

abstract:
  We discuss the formation of antihydrogen atoms ($\bar{\rm H}$) in an
ultra-cold positron-antiproton plasma. For positron densities $n_p\agt 10^8$
cm$^{-3}$ the characteristic formation time of stable $\bar{H}$ is determined
by collisional relaxation of highly excited atoms produced in the process of
3-body Thompson recombination. Relying on the mechanisms of ``replacement
collisions'' and ``transverse collisional drift'' we find a bottleneck in the
relaxation kinetics and analyze the physical consequences of this phenomenon.


title: The General Structure of Eigenvalues of Non-linear Oscillators

abstract:
  Hilbert Spaces of bounded one dimensional non-linear oscillators are studied.
It is shown that the eigenvalue structure of all such oscillators have the same
general form. They are dependent only on the ground state energy of the system
and a single functional $\lambda(H)$ of the Hamiltonian $H$ whose form depends
explicitly on $H$. It is also found that the Hilbert Space of the non-linear
oscillator is unitarily inequivalent to the Hilbert Space of the simple
harmonic oscillator, providing an explicit example of Haag's Theorem. A number
operator for the nonlinear oscillator is constructed and the general form of
the partition function and average energy of an non-linear oscillator in
contact with a heat bath is determined. Connection with the WKB result in the
semi-classical limit is made. This analysis is then applied to the specific
case of the $x^4$ anharmonic oscillator.


title:
Coherent Population Trapping with Losses on the Sodium D1 Line Hanle
  Effect

abstract:
  We consider the coherent population trapping phenomenon in a thermal sodium
atomic beam. We compare the different coherent population trapping schemes that
can be established on the D1 line using the Zeeman sublevels of a given ground
hyperfine state. The coherent population trapping preparation is examined by
means of a Hanle effect configuration. The efficiency of the coherent
population trapping phenomenon has been examined in presence of optical pumping
into hyperfine levels external to those of the excited transition. We show that
both the contrast and the width of the coherent population trapping resonance
strongly decrease when the optical pumping rate is increased. In the
experiment, the loss rate due to optical pumping has been controlled by means
of a laser repump of variable intensity.


title: Non-Recursive Multiplicity Formulas for $A_N$ Lie Algebras

abstract:
  It is shown that there are infinitely many formulas to calculate
multiplicities of weights participating in irreducible representations of $A_N$
Lie algebras. On contrary to recursive character of Kostant and Freudenthal
multiplicity formulas, they provide us systems of linear algebraic equations
with N-dependent polinomial coefficients. These polinomial coefficients are in
fact related with polinomials which represent eigenvalues of Casimir operators.


title: A Note on the Relativistic Covariance of the $B-$ Cyclic Relations

abstract:
  It is shown that the Evans-Vigier modified electrodynamics is compatible with
the Relativity Theory.


title: Quasi-Monte Carlo, Discrepancies and Error Estimates

abstract:
  We discuss the problem of defining an estimate for the error in quasi-Monte
Carlo integration. The key issue is the definition of an ensemble of
quasi-random point sets that, on the one hand, includes a sufficiency of
equivalent point sets, and on the other hand uses information on the degree of
uniformity of the point set actually used, in the form of a discrepancy or
diaphony. A few examples of such discrepancies are given. We derive the
distribution of our error estimate in the limit of large number of points. In
many cases, Gaussian central limits are obtained. We also present numerical
results for the quadratic star-discrepancy for a number of quasi-random
sequences.


title:
A one-map two-clock approach to teaching relativity in introductory
  physics

abstract:
  This paper presents some ideas which might assist teachers incorporating
special relativity into an introductory physics curriculum. One can define the
proper-time/velocity pair, as well as the coordinate-time/velocity pair, of a
traveler using only distances measured with respect to a single ``map'' frame.
When this is done, the relativistic equations for momentum, energy, constant
acceleration, and force take on forms strikingly similar to their Newtonian
counterparts. Thus high-school and college students not ready for Lorentz
transforms may solve relativistic versions of any single-frame Newtonian
problems they have mastered. We further show that multi-frame calculations
(like the velocity-addition rule) acquire simplicity and/or utility not found
using coordinate-velocity alone.


title:
Influence of the Head Group Size on the Direction of Tilt in Langmuir
  Monolayers

abstract:
  A model of rods with heads of variable size, which are confined to a planar
surface, is used to study the influence of the head group size on tilted phases
in Langmuir monolayers. Simple free energy considerations as well as exact zero
temperature calculations indicate that molecules with small head groups tilt
towards next nearest neighbors, and molecules with larger head groups towards
nearest neighbors. This provides a possible explanation for recent experimental
results, and for details of the generic phase diagram for fatty acid
monolayers.


title:
Origin of entropy convergence in hydrophobic hydration and protein
  folding

abstract:
  An information theory model is used to construct a molecular explanation why
hydrophobic solvation entropies measured in calorimetry of protein unfolding
converge at a common temperature. The entropy convergence follows from the weak
temperature dependence of occupancy fluctuations for molecular-scale volumes in
water. The macroscopic expression of the contrasting entropic behavior between
water and common organic solvents is the relative temperature insensitivity of
the water isothermal compressibility. The information theory model provides a
quantitative description of small molecule hydration and predicts a negative
entropy at convergence. Interpretations of entropic contributions to protein
folding should account for this result.


title: Stochastic resonance in a model neuron with reset

abstract:
  The response of a noisy integrate-and-fire neuron with reset to periodic
input is investigated. We numerically obtain the first-passage-time density of
the pertaining Ornstein-Uhlenbeck process and show how the power spectral
density of the resulting spike train can be determined via Fourier transform.
The neuron's output clearly exhibits stochastic resonance.


title: Ramsey type Sub-Recoil Cooling

abstract:
  We experimentally study the motion of atoms interacting with a periodically
pulsed near resonant standing wave. For discrete pulse frequencies we observe a
comb-like momentum distribution. The peaks have widths of 0.3 recoil momenta
and a spacing which is an integer multiple of the recoil momentum. The atomic
population is trapped in ground states which periodically evolve to dark states
each time the standing wave is switched on.


title: A Theory of Measurement Uncertainty Based on Conditional Probability

abstract:
  A theory of measurement uncertainty is presented, which, since it is based
exclusively on the Bayesian approach and on the subjective concept of
conditional probability, is applicable in the most general cases.
  The recent International Organization for Standardization (ISO)
recommendation on measurement uncertainty is reobtained as the limit case in
which linearization is meaningful and one is interested only in the best
estimates of the quantities and in their variances.

categories: physics.data-an astro-ph bayes-an hep-ph nucl-ex


title: Nonlinear Two-dimensional potential plasma wake waves

abstract:
  The condition for potential description of the wake waves,generated by flat
or cylindrical driving electron bunch in cold plasma is derived.
  The two-dimensional nonlinear equation for potential valid for small values
of that is obtained and solved by the separation of variables. Solutions in the
form of cnoidal waves,existing behind the moving bunch at small values of
vertical coordinate,are obtained.In particular,at some boundary
conditions,corresponding to blow-out regime in the underdense plasma,the
solution represents by a solitary nonlinear wave.
  Approximate solution is also obtained using the method of multiple sacales.
  The indications are obtained that the dependense of the amplitudes on
longitudinal coordinate determines essentially,even in the first
approximation,by driving bunch charge distribution.The wake wave amplitude can
increase at some conditions along the longitudinal distance from the rear part
of the bunch.


title:
Classical $v_{gr} \neq c$ solutions of Maxwell equations and the
  tunneling photon effect

abstract:
  We propose a very simple but general method to construct solutions of Maxwell
equations propagating with a group velocity $v_{gr} \neq c$. Applications to
wave guides and a possible description of the known experimental evidences on
photonic tunneling are discussed.


title: Band Population Measurements in a Purely Optical Dark Lattice

abstract:
  We create a dark optical lattice structure using a blue detuned laser field
coupling an atomic ground state of total angular momentum F simultaneously to
two excited states with angular momenta F and F-1, or F and F+1. The atoms are
trapped at locations of purely circular polarization. The cooling process
efficiently accumulates almost half of the atomic population in the lowest
energy band which is only weakly coupled to the light field. The populations of
the two lowest energy bands reaches 70%. Kinetic energies on the order of the
recoil energy are obtained by adiabatically reducing the optical potential. The
band populations are directly mapped on free particle momentum intervals by
this adiabatic release. In an experiment with subrecoil momentum resolution we
measure the band populations and find good absolute agreement with the
theoretically calculated steady state band populations.


title: An all-optical gray lattice for atoms

abstract:
  We create a gray optical lattice structure using a blue detuned laser field
coupling an atomic ground state of angular momentum J simultaneously to two
excited states with angular momenta J and J-1. The atoms are cooled and trapped
at locations of purely circular polarization. The cooling process efficiently
accumulates almost half of the atomic population in the lowest energy band
which is only weakly coupled to the light field. Very low kinetic temperatures
are obtained by adiabatically reducing the optical potential. The dynamics of
this process is analysed using a full quantum Monte Carlo simulation. The
calculations explicitly show the mapping of the band populations on the
corresponding momentum intervals of the free atom. In an experiment with
subrecoil momentum resolution we measure the band populations and find
excellent absolut agreement with the theoretical calculations.


title:
On the squared spin-orbit correction to the positronium fine-structure
  splitting

abstract:
  In the recent paper by Zhang the order $\alpha^4 R_{\infty}$ corrections to
the positronium P levels were reconsidered. Those calculations confirm our
corresponding results, except for the contribution due to the squared
spin-orbit interaction. We present here a new derivation of our previous result
for this last correction, this derivation being to our opinion both simple and
convincing.


title: Information physics: From energy to codes

abstract:
  We illustrate in terms familiar to modern day science students that: (i) an
uncertainty slope mechanism underlies the usefulness of temperature via its
reciprocal, which is incidentally around 42 [nats/eV] at the freezing point of
water; (ii) energy over kT and differential heat capacity are ``multiplicity
exponents'', i.e. the bits of state information lost to the environment outside
a system per 2-fold increase in energy and temperature respectively; (iii) even
awaiting description of ``the dice'', gambling theory gives form to the laws of
thermodynamics, availability minimization, and net surprisals for measuring
finite distances from equilibrium, information content differences, and
complexity; (iv) heat and information engine properties underlie the biological
distinction between autotrophs and heterotrophs, and life's ongoing symbioses
between steady-state excitations and replicable codes; and (v) mutual
information resources (i.e. correlations between structures e.g. a phenomenon
and its explanation, or an organism and its niche) within and across six
boundary types (ranging from the edges of molecules to the gap between
cultures) are delocalized physical structures whose development is a big part
of the natural history of invention. These tools might offer a physical
framework to students of the code-based sciences when considering such
disparate (and sometimes competing) issues as conservation of available work
and the nurturing of genetic or memetic diversity.

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


title: Ejection Energy of Photoelectrons in Strong Field Ionization

abstract:
  We show that zero ejection energy of the photoelectrons is classically
impossible for hydrogen-like ions, even when field ionization occurs
adiabatically. To prove this we transform the basic equations to those
describing two 2D anharmonic oscillators. The same method yields an alternative
way to derive the anomalous critical field of hydrogen-like ions. The
analytical results are confirmed and illustrated by numerical simulations. PACS
Number: 32.80.Rm


title:
Multielectron dissociative ionization of molecules by intense laser
  radiation

abstract:
  We solve the hydrodynamic-ballistic equations of motion for a one-dimensional
time-dependent Thomas-Fermi model of Cl_2 exposed to an intense subpicosecond
laser field, and observe simultaneous multielectron ionization and molecular
dissociation. The fragment kinetic energy defect with respect to the simple
Coulomb explosion picture is found to originate in ejected-electron screening
of the escaping fragments; its magnitude agrees with that observed in recent
experiments.


title: Massively Parallel Computing of Turbulent Transport in Tokamaks

abstract:
  With the advent of the gyrokinetic formalism, recent developments in
low-noise nonlinear $\delta f$ methods, and enormous gains in computing power,
large-scale gyrokinetic simulations have become an important tool for improved
understanding of anomalous transport in tokamaks. Simulating the non-linear
behaviour requires solving for the perturbations of distrbution function in
five dimensions. We use a particle-in-cell approach to solve the equations via
the non-linear characteristic method. The code has been parallelized for a
variety of architecures (C90, CM-5, T3D) using a 1-D domain decomposition along
the torroidal axis, for which the number of particles in each cell remains
approximately constant. The quasi uniform distribution of particles, which
minimizes load imbalance, coupled with the relatively small movement of
particles across cells, which minimizes communications, makes this problem
ideally suited to massively parallel architectures. We present the performance
of the program as a function of number of processors and problem size, which
demonstrates the near perfect scalability of the code. In addition, we discuss
the scientific results obtained from the code and the types of problems that
will be addressable as the next generation of super-computers become available.


title: Adiabatically changing the phase-space density of a trapped Bose gas

abstract:
  We show that the degeneracy parameter of a trapped Bose gas can be changed
adiabatically in a reversible way, both in the Boltzmann regime and in the
degenerate Bose regime. We have performed measurements on spin-polarized atomic
hydrogen in the Boltzmann regime demonstrating reversible changes of the
degeneracy parameter (phase-space density) by more than a factor of two. This
result is in perfect agreement with theory. By extending our theoretical
analysis to the quantum degenerate regime we predict that, starting close
enough to the Bose-Einstein phase transition, one can cross the transition by
an adiabatic change of the trap shape.


title:
Application of a symmetry-adapted algebraic model to the vibratioinal
  spectrum of methane

abstract:
  The stretching and bending vibrations of methane are studied in the framework
of a symmetry-adapted algebraic model. The model is based on the realization of
the one-dimensional Morse potential in terms of a $U(2)$ algebra. For the 44
observed energies we obtain a fit with a r.m.s. deviation of 1.16 cm$^{-1}$
which is an order of magnitude more accurate than previous algebraic
calculations.


title: Interference of Resonance Fluorescence from two four-level atoms

abstract:
  In a recent experiment by Eichmann et al., polarization-sensitive
measurements of the fluorescence from two four-level ions driven by a linearly
polarized laser were made. Depending on the polarization chosen, different
degrees of interference were observed. We carry out a theoretical and numerical
study of this system, showing that the results can largely be understood by
treating the atoms as independent radiators which are synchronized by the phase
of the incident laser field. The interference and its loss may be described in
terms of the difference between coherent and incoherent driving of the various
atomic transitions in the steady-state. In the numerical simulations, which are
carried out using the Monte Carlo wave function method, we remove the
assumption that the atoms radiate independently and consider the photodetection
process in detail. This allows us to see the total interference pattern build
up from individual photodetections and also to see the effects of
superfluorescence, which become important when the atomic separation is
comparable to an optical wavelength. The results of the calculations are
compared with the experiment. We also carry out simulations in the non
steady-state regime and discuss the relationship between the visibility of the
interference pattern and which-path considerations.


title: A symmetry-adapted algebraic approach to molecular spectroscopy

abstract:
  We apply a symmetry-adapted algebraic model to the vibrational excitations in
D_3h and T_d molecules. A systematic procedure is used to establish the
relation between the algebraic and configuration space formulations. In this
way we have identified interaction terms that were absent in previous
formulations of the vibron model. The inclusion of these new interactions leads
to reliable spectroscopic predictions. We illustrate the method for the D_3h
triatomic molecules, H_3^+, Be_3 and Na_3, and the T_d molecules, Be_4 and
CH_4.


title: Optical response of small carbon clusters

abstract:
  We apply the time-dependent local density approximation (TDLDA) to calculate
dipole excitations in small carbon clusters. A strong low-frequency mode is
found which agrees well with observation for clusters C_n with n in the range
7-15. The size dependence of the mode may be understood simply as the classical
resonance of electrons in a conducting needle. For a ring geometry, the lowest
collective mode occurs at about twice the frequency of the collective mode in
the linear chain, and this may also be understood in simple terms.


title: Nonlinear Maxwell Equations

abstract:
  A new relativistic invariant version of nonlinear Maxwell equations is
offerred. Some properties of these equations are considered.


title: Simple supersymmetric methods in neutron diffusion

abstract:
  We present the supersymmetric Witten and double Darboux (strictly
isospectral) constructions as applied to the diffusion of thermal neutrons from
an infinitely long line source. While the Witten construction is just a
mathematical scheme, the double Darboux method introduces a one-parameter
family of diffusion solutions which are strictly isospectral to the stationary
solution. They correspond to a Darboux-transformed diffusion length which is
flux dependent


title: Developments in time analysis of particle and photon tunnelling

abstract:
  A compact analysis of development and prospects in the study of the
tunnelling evolution is given. A new systematization of various approaches to
defining tunnelling times in the light of time as a quantum mechanical
observable is proposed. The problem of superluminal group velocities, without
violations of special relativity, is also taken in account. Then a particular
attention is devoted to the presentation of new results on the analogy between
particle and photon tunnelling and analysis of the causality validity during
tunnelling. [PACS nos. 03.40.Kf, 03.50.De, 41.20.Jb, 41.20.Bt, 42.25.Bs,
03.30.+p, 03.65.-w].


title: Towards a Simple Model of Compressible Alfvenic Turbulence

abstract:
  A simple model collisionless, dissipative, compressible MHD (Alfvenic)
turbulence in a magnetized system is investigated. In contrast to more familiar
paradigms of turbulence, dissipation arises from Landau damping, enters via
nonlinearity, and is distributed over all scales. The theory predicts that two
different regimes or phases of turbulence are possible, depending on the ratio
of steepening to damping coefficient (m_1/m_2). For strong damping
(|m_1/m_2|<1), a regime of smooth, hydrodynamic turbulence is predicted. For
|m_1/m_2|>1, steady state turbulence does not exist in the hydrodynamic limit.
Rather, spikey, small scale structure is predicted.

categories: physics.plasm-ph adap-org astro-ph nlin.AO physics.space-ph


title: A general algebraic model for vibrational molecular spectroscopy

abstract:
  We present a symmetry-adapted version of the vibron model and discuss an
application to D_{3h} triatomic molecules: H_3^+, Be_3 and Na_3^+.


title: A dynamical model of the chemical bond

abstract:
  A new approach to chemical bonding is introduced in order to provide an
improved understanding of the connection between basic quantum mechanics and
the covalent pair bond. It's focus is on the fact that the energy of the bond
is largely given by the kinetic energy of the electrons, while the Coulomb
forces are only comparable to the kinetic energy terms close to the atomic
nuclei, where they define the shape and the size of the atomic orbitals. If
atomic orbitals are used as a starting point, the kinetic energy operator is
sufficient to determine the energy of the chemical bond. The simple
mathematical structure of this operator allows a calculation of bond energy as
a function of the distance between the atoms. For Gaussian wavefunctions, it is
possible to calculate this bonding potential analytically, determining the bond
length, the bond energy and the elasticity of the bond from only a single
parameter, the width of the atomic wavefunction. It is shown that the results
correspond surprisingly well with experimental values for diatomic molecules.

categories: physics.chem-ph cond-mat.mtrl-sci physics.ed-ph quant-ph


title: Theory for Diffusion-Limited Oscillating Chemical Reactions

abstract:
  A kinetic description of lattice-gas automaton models for reaction-diffusion
systems is presented. It provides corrections to the mean-field rate equations
in the diffusion-limited regime. When applied to the two-species Maginu model,
the theory gives an excellent quantitative prediction of the effect of slow
diffusion on the periodic oscillations of the average concentrations in a
spatially homogeneous state.

categories: physics.chem-ph cond-mat nlin.PS patt-sol


title: Casimir invariants and characteristic identities for $gl(\infty )$

abstract:
  A full set of (higher order) Casimir invariants for the Lie algebra
$gl(\infty )$ is constructed and shown to be well defined in the category
$O_{FS}$ generated by the highest weight (unitarizable) irreducible
representations with only a finite number of non-zero weight components.
Moreover the eigenvalues of these Casimir invariants are determined explicitly
in terms of the highest weight. Characteristic identities satisfied by certain
(infinite) matrices with entries from $gl(\infty )$ are also determined and
generalize those previously obtained for $gl(n)$ by Bracken and Green.$^{1,2}$


title: A New View of the Universe

abstract:
  A new, very different physical model of the universe is proposed. Its virtues
include unifying relativity and quantum mechanics, and particles with de
Broglie waves. It also appears to provide a truly unified physical basis for
electromagnetic, gravitational and nuclear forces. The basic system is a
four-dimensional Euclidean space, containing an array of nonlinear "flow"
waves. These repeat in one dimension, called [phi]. As in Newtonian mechanics,
time is treated as an additional, unidirectional parameter describing the
evolution of the system. Nevertheless, this wave system is shown be inherently
relativistic. Further self-organizing patterns arise within the overall wave
structure. Called "wavicles," these have intrinsic quantized fields, "spin,"
and rest energy, and represent elementary particles. Relativistic expressions
are derived for particle behavior in scalar, vector and gravitational
potentials. Proper representations of these potentials, based on the wave
fields and associated [phi] flows of wavicles, are also obtained. As in the
causal quantum mechanics of de Broglie and Bohm, wavicles exist continuously
and follow definite, stochastic trajectories. Although experimentally
equivalent to Einstein's special relativity, this theory differs fundamentally
from his general relativity and the associated Big Bang model. According to
Linde, the latter predict a large-scale space-time curvature roughly 60 orders
of magnitude greater than observed values. Here a flat large-scale geometry is
predicted, in agreement with the observed distribution of galaxies. This theory
is also consistent with recent observations pertaining to the age of the
universe.


title: Long-range interactions of lithium atoms

abstract:
  The long-range interactions of two atoms, of an atom and a dielectric wall,
of an atom and a perfectly conducting wall, and of an atom between two
perfectly conducting walls are calculated, including the effects of
retardation, for Li using dynamic polarizabilities determined from highly
correlated, variationally determined wave functions.


title: Three-Body Configuration Space Calculations with Hard Core Potentials

abstract:
  We present a mathematically rigorous method suitable for solving three-body
bound state and scattering problems when the inter-particle interaction is of a
hard-core nature. The proposed method is a variant of the Boundary Condition
Model and it has been employed to calculate the binding energies for a system
consisting of three ^4He atoms. Two realistic He-He interactions of Aziz and
collaborators, have been used for this purpose. The results obtained compare
favorably with those previously obtained by other methods. We further used the
model to calculate, for the first time, the ultra-low energy scattering phase
shifts. This study revealed that our method is ideally suited for three-body
molecular calculations where the practically hard-core of the inter-atomic
potential gives rise to strong numerical inaccuracies that make calculations
for these molecules cumbersome.


title: An efficient algorithm for two-dimensional central-force rigidity

abstract:
  Given a structure made up of n sites connected by b bars, the problem of
recognizing which subsets of sites form rigid units is not a trivial one,
because of the non-local character of rigidity in central-force systems. Even
though this is a very old problem of statics, no simple algorithms are
available for it so the most usual approach has been to solve the elastic
equations, which is very time-consuming for large systems. Recently an integer
algorithm was proposed for this problem in two dimensions, using matching
methods from graph theory and Laman's theorem for two-dimensional graphs. The
method is relatively simple, but its time complexity grows as $n^2$ in the
worst case, and almost as fast on practical cases, so that an improvement is
highly desirable. I describe here a further elaboration of that procedure,
which relies upon the description of the system as a collection of rigid bodies
connected by bars, instead of sites connected by bars. Sets of rigidly
connected objects are replaced by a unique body, and this is done recursively
as more rigid connections between bodies are discovered at larger scales. As a
consequence of this ``rescaling transformation'', our algorithm has much
improved average behavior, even when its worst-case complexity remains $n^2$.
The time complexity of the body-bar algorithm is found to scale as $n^{1.12}$
for the randomly diluted triangular lattice, while the original site-bar
version scales as $n^{1.9}$ on the same problem.


title: Aharonov-Bohm Effect with $\delta$--type Interaction

abstract:
  A quantum particle interacting with a thin solenoid and a magnetic flux is
described by a five-parameter family of Hamilton operators, obtained via the
method of self-adjoint extensions. One of the parameters, the value of the
flux, corresponds to the Aharonov-Bohm effect; the other four parameters
correspond to the strength of a singular potential barrier. The spectrum and
eigenstates are computed and the scattering problem is solved.


title: Differentials of higher order in non commutative differential geometry

abstract:
  In differential geometry, the notation d^n f along with the corresponding
formalism has fallen into disuse since the birth of exterior calculus. However,
differentials of higher order are useful objects that can be interpreted in
terms of functions on iterated tangent bundles (or in terms of jets). We
generalize this notion to the case of non commutative differential geometry.
For an arbitrary associative algebra A, one already knows how to define the
differential algebra Omega(A) of universal differential forms over A. We define
Leibniz forms of order n (these are not forms of degree n, ie they are not
elements of Omega^n A) as particular elements of what we call the ``iterated
frame algebra'' of order n, F_n A, which is itself defined as the 2^n tensor
power of the algebra A. We give a system of generators for this iterated frame
algebra and identify the A-module of forms of order n as a particular vector
subspace included in the space of universal one-forms built over the iterated
frame algebra of order n-1. We study the algebraic structure of these objects,
recover the case of the commutative differential calculus of order n (Leibniz
differentials) and give a few examples.


title: Comparisons Between Modeling and Measured Performance of the BNL Linac

abstract:
  Quite good agreement has been achieved between computer modeling and actual
performance of the Brookhaven 200 MeV Linac. We will present comparisons
between calculated and measured performance for the beam transport through the
RFQ, the 6 meter transport from RFQ to the linac and meching and transport
through the linac.


title:
Fluid Models for Kinetic Effects on Coherent Nonlinear Alfven Waves. I.
  Fundamental Theory

abstract:
  Collisionless regime kinetic models for coherent nonlinear Alfven wave
dynamics are studied using fluid moment equations with an approximate closure
anzatz. Resonant particle effects are modelled by incorporating an additional
term representing dissipation akin to parallel heat conduction. Unlike
collisional dissipation, parallel heat conduction is presented by an integral
operator. The modified derivative nonlinear Schrodinger equation thus has a
spatially nonlocal nonlinear term describing the long-time evolution of the
envelope of parallel-propagating Alfven waves, as well. Coefficients in the
nonlinear terms are free of the 1/(1-beta) singularity usually encountered in
previous analyses, and have very a simple form which clarifies the physical
processes governing the large amplitude Alfvenic nonlinear dynamics. The
nonlinearity appears via coupling of an Alfvenic mode to a kinetic ion-acoustic
mode. Damping of the nonlinear Alfven wave appears via strong Landau damping of
the ion-acoustic wave when the electron-to-ion temperature ratio is close to
unity. For a (slightly) obliquely propagating wave, there are finite Larmor
radius corrections in the dynamical equation. This effect depends on the angle
of wave propagation relative to B_0 and vanishes for the limit of strictly
parallel propagation. Explicit magnetic perturbation envelope equations
amenable to further analysis and numerical solution are obtained. Implications
of these models for collisionless shock dynamics are discussed.


title:
Fluid Models for Kinetic Effects on Coherent Nonlinear Alfven Waves. II.
  Numerical Solutions

abstract:
  The influence of various kinetic effects (e.g. Landau damping, diffusive and
collisional dissipation, and finite Larmor radius terms) on the nonlinear
evolution of finite amplitude Alfvenic wave trains in a finite-beta environment
is systematically investigated using a novel, kinetic nonlinear Schrodinger
(KNLS) equation. The dynamics of Alfven waves is sensitive to the sense of
polarization as well as the angle of propagation with respect to the ambient
magnetic field. Numerical solution for the case with Landau damping reveals the
formation of dissipative structures, which are quasi-stationary, S-polarized
directional (and rotational) discontinuities which self-organize from parallel
propagating, linearly polarized waves. Parallel propagating circularly
polarized packets evolve to a few circularly polarized Alfven harmonics on
large scales. Stationary arc-polarized rotational discontinuities form from
obliquely propagating waves. Collisional dissipation, even if weak, introduces
enhanced wave damping when beta is very close to unity. Cyclotron motion
effects on resonant particle interactions introduce cyclotron resonance into
the nonlinear Alfven wave dynamics.

categories: physics.plasm-ph adap-org astro-ph nlin.AO nlin.PS patt-sol physics.space-ph


title:
Resonance Broadening Induced Nonlinear Saturation of Kinetic Alfven
  Turbulence in the Interplanetary Plasma

abstract:
  The saturation of ion cyclotron Alfven turbulence excited by beam particles
is investigated using resonance broadening theory. The stochastic scattering
which decorrelates particles, includes both random acceleration by electric
fields and a turbulent magnetic mirroring effect. Turbulent mirroring is shown
to yield non-Gaussian corrections to the orbits even if the random electric and
magnetic fields are Gaussian. The predicted steady-state turbulence level
exhibits a peaked anglular distribution, with a maximum near Theta ~ 60
degrees.


title: Pick-up ion dynamics at the structured quasi-perpendicular shock

abstract:
  We study the pickup ion dynamics and mechanism of multiple reflection and
acceleration at the structured quasi-perpendicular supercritical shock. The
motion of the pickup ions in the shock is studied analytically and numerically
using the test particle analysis in the model shock front. The analysis shows
that slow pickup ions may be accelerated at the shock ramp to high energies.
The maximum ion energy is determined by the fine structure of the
electro-magnetic field at the shock ramp and decreases when the angle between
magnetic field and shock normal decreases. Evolution of pickup ion distribution
across the nearly-perpendicular shock and pickup ion spectrum is also studied
by direct numerical analysis.


title:
Steady state behaviour in atomic three-level lambda and ladder systems
  with incoherent population pumping

abstract:
  The steady state in three-level lambda and ladder systems is studied. It is
well-known that in a lambda system this steady state is the coherent population
trapping state, independent of the presence of spontaneous emission. In
contrast, the steady state in a ladder system is in general not stable against
radiative decay and exhibits a minimum in the population of the ground state.
It is shown that incoherent population pumping destroys the stability of the
coherent population trapping state in the lambda system and suppresses a
previously discovered sharp dip in the steady state response. In the ladder
system the observed minimum disappears in the presence of an incoherent pump on
the upper transition.


title: Does antimatter emit a new light ?

abstract:
  We identify a number of problematic aspects of current classical and quantum
theories of antimatter; we introduce a new mathematical formalism which is an
antiautomorphic image of that of matter equivalent to charge conjugation at the
operator level, but applicable from Newton's equations to quantum mechanics; we
show that the emerging new theory of antimatter recovers known experimental
data on electroweak interactions; we finally identity the following predictions
of the theory: 1) reversal in the field of matter of the gravitational
curvature (antigravity) for stable antiparticles and their bound states, such
as the anti-hydrogen atom; 2) conventional (attractive) gravity for a bound
state of an elementary particle and its antiparticle, such as the positronium;
and 3) prediction that the anti- hydrogen atom emits a new photon which
coincides with the conventional photon for all electroweak interactions but
experiences repulsion in the gravitational field of matter.


title: The Complete Cohomology of $E_8$ Lie Algebra

abstract:
  It is shown, for any irreducible representation of $E_8$ Lie algebra, that
eigenvalues of Casimir operators can be calculated in the form of invariant
polinomials which are decomposed in terms of $A_8$ basis functions. The general
method is applied for degrees 8,12 and 14 for which 2,8 and 19 invariant
polinomials are obtained respectively. For each particular degree, these
invariant polinomials can be taken to be $E_8$ basis functions in the sense
that any Casimir operator of $E_8$ has always eigenvalues which can be
expressed as linear superpositions of them. This can be investigated by showing
that each one of these $E_8$ basis functions gives us a linear equation to
calculate weight multiplicities.


title:
New Expression for the Transverse Deflection of Relativistic Particle in
  High-Frequency Fields and Correlation with Panofsky- Wenzel Theorem

abstract:
  It is shown that change in transverse momentum of a relativistic particle,
crossing an accelerating cavity parallel to its axis, may be presented as an
integral over trajectory, the integrand of which is proportional to the
component of magnetic field parallel to this axis. The changes in two
transversal components of momentum are equal in value but opposite in sign. The
obtained result is compared with Panofsky-Wenzel theorem


title: New Symmetries in Mathematical Physics Equations

abstract:
  An algorithm for studing the symmetrical properties of the partial
differential equation of the type Lu=0 is proposed. By symmetry of this
equation we mean the operators Q satisfying commutational relations of order p
more than p=1 on the solutions u: [L...[L,Q]...]u=0. It is shown, that within
the framework of the proposed method with p=2 the relativistic D'Alembert and
Maxwell equations are the Galilei symmetrical ones. Analogously, with p=2 the
Galilei symmetrical Schroedinger equation is the relativistic symmetrical one.
In both cases the standard symmetries are realized with p=1.


title: The hyperfine structure of the hydrogen molecular ion

abstract:
  Theoretical investigations of the hyperfine structure of the hydrogen
molecular ion (one electron and two protons) are discussed. The nuclear
spin-rotation interaction has been found to be of the same sign as in the
hydrogen molecule and the hyperfine transition frequencies can be accurately
predicted. With measurements of the hyperfine structure of the deuterium
molecular ion (or of HD+) it should be possible to obtain a value of the
deuteron quadrupole moment that could be compared with the values obtained from
the deuterium molecule and from nuclear theory.


title:
Exact Dirac equation calculation of ionization and pair production
  induced by ultrarelativistic heavy ions

abstract:
  An exact solution of the time-dependent Dirac equation for ionization and
pair production induced by ultrarelativistic heavy ion collisions is presented.
Exact transition probabilities, equivalent to those that would be obtained in
an untruncated basis coupled channels calculation, are presented. Exact
bound-electron positron pair production probabilities are calculated to be
mostly smaller than those calculated with the same potential in perturbation
theory at impact parameters small enough for differences to occur.


title: Implementation of Endomorphisms of the CAR Algebra

abstract:
  The implementation of non-surjective Bogoliubov transformations in Fock
states over CAR algebras is investigated. Such a transformation is
implementable by a Hilbert space of isometries if and only if the well-known
Shale-Stinespring condition is met. In this case, the dimension of the
implementing Hilbert space equals the square root of the Watatani index of the
associated inclusion of CAR algebras, and both are determined by the Fredholm
index of the corresponding one-particle operator. Explicit expressions for the
implementing operators are obtained, and the connected components of the
semigroup of implementable transformations are described.


title: On The Even CAR Algebra

abstract:
  We exhibit a family of *-isomorphisms mapping the CAR algebra onto its even
subalgebra.


title: $O_\infty$ Realized on Bose Fock Space

abstract:
  We study the semigroup of Bogoliubov endomorphisms of the canonical
commutation relations which give rise to representations of the Cuntz algebra
$O_\infty$ on Fock space and describe the corresponding Cuntz algebra
generators in detail.


title: Hamiltonian Dynamics of Darwin Systems

abstract:
  We present a Hamiltonian approach for the wellknown Eigen model of the Darwin
selection dynamics. Hamiltonization is carried out by means of the embedding of
the population variable space, describing behavior of the system, into the
space of doubled dimension by introducing additional dynamic variables. Besides
the study of the formalism, we try to interpret its basic elements (phase
space, Hamiltonian, geometry of solutions) in terms of the theoretical biology.
A geometric treatment is given for the considered system dynamics in terms of
the geodesic flows in the Euclidean space where the population variables serve
as curvilinear coordinates. The evolution of the distribution function is found
for arbitrary distributed initial values of the population variables.


title:
Generator-Invertor-Dumper System of Electron (Positron) Bunches Moving
  in Cold plasma for Development of Strong Accelerating Electric Field

abstract:
  It is shown that high accelerating gradient can be obtained in a specially
constructed system of electron (positron) bunches, moving in cold plasma,with
definite density. These combined bunch systems do not generate the wake fields
behind them and can pass through the plasma column in a periodic sequence. The
consideration is carried out numericaly and analyticaly in one dimensional
approach, (which can be applied to finite system when its transverse dimensions
are larger than plasma wave length, divided by $2\pi$). The possibilities of
the experimental tests by measuring the predicted energy gain are discussed on
the examples of Argonne Wakefield Accelerator and induction linac with typical
parameters.


title: Symmetry breaking in crossed magnetic and electric fields

abstract:
  We present the first observations of cylindrical symmetry breaking in highly
excited diamagnetic hydrogen with a small crossed electric field, and we give a
semiclassical interpretation of this effect. As the small perpendicular
electric field is added, the recurrence strengths of closed orbits decrease
smoothly to a minimum, and revive again. This phenomenon, caused by
interference among the electron waves that return to the nucleus, can be
computed from the azimuthal dependence of the classical closed orbits.


title:
Dimensional perturbation theory for vibration-rotation spectra of linear
  triatomic molecules

abstract:
  A very efficient large-order perturbation theory is formulated for the
nuclear motion of a linear triatomic molecule. To demonstrate the method, all
of the experimentally observed rotational energies, with values of $J$ almost
up to 100, for the ground and first excited vibrational states of CO$_2$ and
for the ground vibrational states of N$_2$O and of OCS are calculated. All
coupling between vibration and rotation is included. The perturbation
expansions reported here are rapidly convergent. The perturbation parameter is
$D^{-1/2}$, where $D$ is the dimensionality of space. Increasing $D$ is
qualitatively similar to increasing the angular momentum quantum number $J$.
Therefore, this approach is especially suited for states with high rotational
excitation. The computational cost of the method scales only as $JN_v^{5/3}$,
where $N_v$ is the size of the vibrational basis set.


title: Supersymmetric techniques applied to the Jacobi equation

abstract:
  The simple supersymmetric approach recently used by Dutt, Gangopadhyaya, and
Sukhatme [Am. J. Phys. 65 400 (1997)] for spherical harmonics is generalized to
Jacobi equation, including also the intermediate Gegenbauer case


title:
A collaborative theoretical and experimental study of the structure and
  electronic excitation spectrum of the BAr and B(Ar)2 complexes

abstract:
  We report the investigation of the 3s <- 2p transition in the BAr2 cluster.
In a supersonic expansion of B atoms entrained in Ar, at high beam source
backing pressures we observe several features in the fluorescence excitation
spectrum which cannot be assigned to the BAr diatom. Using BAr(X, B) potential
energy curves which reproduce our experimental observations on this molecule
and an Ar-Ar interaction potential, we employ a pairwise additive model, along
with variational and diffusion Monte-Carlo treatments of the nuclear motion, to
determine the lowest vibrational state of the BAr2 cluster. A subsequent
simulation of the fluorescence excitation spectrum reproduces nearly
quantitatively the strongest feature in our experimental spectrum not
assignable to BAr. Because of the barrier in the BAr(B 2Sigma+) potential
energy curve, the 3s <- 2p transition in the BAr2 cluster is predicted to have
an asymmetric profile, as is found experimentally.


title: Quantum Molecular Dynamics of Partially Ionized Plasmas

abstract:
  We study a partially ionized hydrogen plasma by means of quantum molecular
dynamics, which is based on wave packets. We introduce a new model which
distinguishes between free and bound electrons. The free electrons are modelled
as Gaussian wave packets with fixed width. For the bound states the 1s-wave
function of the hydrogen atom is assumed. In our simulations we obtain
thermodynamic properties in the equilibrium such as the internal energy and the
degree of ionization. The degree of ionization is in good agreement with
theoretical predictions. The thermodynamic functions agree well with results
from quantum statistics for 10000K < T < 40000K.


title: Lie Symmetries of the Self-Dual Yang-Mills Equations

abstract:
  We investigate Lie symmetries of the self-dual Yang-Mills equations in
four-dimensional Euclidean space (SDYM). The first prolongation of the symmetry
generating vector fields is written down, and its action on SDYM computed.
Determining equations are then obtained and solved completely. Lie symmetries
of SDYM in Euclidean space are in exact correspondence with symmetries of the
full Yang-Mills equations in Minkowski space.


title:
Continuous control of ionization wave chaos by spatially derived
  feedback signals

abstract:
  In the positive column of a neon glow discharge, two different types of
ionization waves occur simultaneously. The low-dimensional chaos arising from
the nonlinear interaction between the two waves is controlled by a continuous
feedback technique. The control strategy is derived from the time-delayed
autosynchronization method. Two spatially displaced points of observation are
used to obtain the control information, using the propagation characteristics
of the chaotic wave.