title:
A general expression for the excitation cross section of polarized atoms
  by polarized electrons

abstract:
  The general expression for excitation cross section of polarized atoms by
polarized electrons is derived by using the methods of the theory of an atom
adapted for polarization. The special cases of the general expression for the
description of the angular distribution and alignment of excited atoms in the
case of polarized and non-polarized atoms as well as the magnetic dichroism of
the total excitation cross section of polarized atoms are obtained. The cross
sections and alignment parameters for the excitation of the autoionizing states
2p$^5$3s$^2$ $^2$P$_{3/2}$ for Na and 3p$^5$4s$^2$ $^2$P$_{3/2}$ for K are
calculated in distorted wave with exchange approximation.


title:
Polynomially scaling spin dynamics simulation algorithm based on
  adaptive state space restriction

abstract:
  The conventional spin dynamics simulations are performed in direct products
of state spaces of individual spins. In a general system of n spins, the total
number of elements in the state basis is >4^n. A system propagation step
requires an action by an operator on the state vector and thus requires >4^2n
multiplications. It is obvious that with current computers there is no way
beyond about ten spins, and the calculation complexity scales exponentially
with the spin system size.
  We demonstrate that a polynomially scaling algorithm can be obtained if the
state space is reduced by neglecting unimportant or unpopulated spin states.
The class of such states is surprisingly wide. In particular, there are
indications that very high multi-spin orders can be dropped completely, as can
all the orders linking the spins that are remote on the interaction graph.
  The computational cost of the propagation step for a ktuples-restricted
densely connected n-spin system with k<<n is O(n^2k). In cases of favourable
interaction topologies (narrow graphs, e.g. in protein NMR) the asymptotic
scaling is linear.


title:
Quasistatic limit of the strong-field approximation describing atoms and
  molecules in intense laser fields

abstract:
  The quasistatic limit of the velocity-gauge strong-field approximation
describing the ionization rate of atomic or molecular systems exposed to linear
polarized laser fields is derived. It is shown that in the low-frequency limit
the ionization rate is proportional to the laser frequency, if a Coulombic
long-range interaction is present. An expression for the corresponding
proportionality coefficient is given. Since neither the saddle-point
approximation nor the one of a small kinetic momentum is used in the
derivation, the obtained expression represents the exact asymptotic limit. This
result is used to propose a Coulomb correction factor. Finally, the
applicability of the found asymptotic expression for non-vanishing laser
frequencies is investigated.


title: A simple atmospheric electrical instrument for educational use

abstract:
  Electricity in the atmosphere provides an ideal topic for educational
outreach in environmental science. To support this objective, a simple
instrument to measure real atmospheric electrical parameters has been developed
and its performance evaluated. This project compliments educational activities
undertaken by the Coupling of Atmospheric Layers (CAL) European research
collaboration. The new instrument is inexpensive to construct and simple to
operate, readily allowing it to be used in schools as well as at the
undergraduate University level. It is suited to students at a variety of
different educational levels, as the results can be analysed with different
levels of sophistication. Students can make measurements of the fair weather
electric field and current density, thereby gaining an understanding of the
electrical nature of the atmosphere. This work was stimulated by the centenary
of the 1906 paper in which C.T.R. Wilson described a new apparatus to measure
the electric field and conduction current density. Measurements using
instruments based on the same principles continued regularly in the UK until
1979. The instrument proposed is based on the same physical principles as
C.T.R. Wilson's 1906 instrument.


title: All-Optical Delay of Images using Slow Light

abstract:
  Two-dimensional images carried by optical pulses (2 ns) are delayed by up to
10 ns in a 10 cm cesium vapor cell. By interfering the delayed images with a
local oscillator, the transverse phase and amplitude profiles of the images are
shown to be preserved. It is further shown that delayed images can be well
preserved even at very low light levels, where each pulse contains on average
less than one photon.


title:
Conformal mapping of ultrasonic crystals: confining ultrasound and
  cochlear-like wave guiding

abstract:
  Conformal mapping of a slab of a two-dimensional ultrasonic crystal generate
a closed geometrical arrangement of ultrasonic scatterers with appealing
acoustic properties. This acoustic shell is able to confine ultrasonic modes.
Some of these internal resonances can be induced from an external wave source.
The mapping of a linear defect produces a wave-guide that exhibits a
spatial-frequency selection analogous to that characteristic of a synthetic
"cochlea". Both, experimental and theoretical results are reported here.


title:
Rosenfeld, Bergmann, Dirac and the Invention of Constrained Hamiltonian
  Dynamics

abstract:
  In a paper appearing in Annalen der Physik in 1930 Leon Rosenfeld invented
the first procedure for producing Hamiltonian constraints. He displayed and
correctly distinguished the vanishing Hamiltonian generator of time evolution,
and the vanishing generator of gauge transformations for general relativity
with Dirac electron and electrodynamic field sources. Though he did not do so,
had he chosen one of his tetrad fields to be normal to his spacetime foliation,
he would have anticipated by almost thirty years the general relativisitic
Hamiltonian first published by Paul Dirac.


title:
Nonlocal effects on the resonant dielectric surface observed by
  near-field optical probing in mid-infrared range

abstract:
  The local electromagnetic field distribution over the dielectric (SiC)
surface illuminated by mid-IR light of frequency close to the lattice resonance
was directly mapped with an apertureless scattering near-field optical
microscope. Half of the sample surface was covered with a metal layer, in which
some small $(0.2-10 \mu m)$ holes were formed. It was found, that due to the
eliminating of collective surface polarization effects, the amplitude of the
electromagnetic field becomes several times higher over such holes than over
infinitely open surface of the same dielectric.


title: Tidal pattern instabilities on multi-moon planets

abstract:
  The equilibrium tide-generating forces in the lunar orbital plane of a planet
of radius R are calculated for the case of N moons of mass M_i orbiting the
planet at instantaneous polar coordinates (D_i, \alpha_i). For the case of a
single moon, there are only two high tides. For the case of two moons, it is
found that there can exist a critical lunar orbital distance at which two high
tides become unstable with respect to formation of three high tides.
Bifurcation diagrams are presented which depict how the angular positions of
the high and low tides on the planet vary with the lunar distances and lunar
separation angle. Tidal stability diagrams, which illustrate the stability
regions for various tidal patterns as a function of lunar distances and lunar
separation angle, are presented for various values of D_2/D_1 and M_2/M_1.
Generally speaking, the aforementioned tidal instability, and hence the
propensity for formation of three high tides on a two-moon planet, exists over
a significant range of lunar distances and separation angles provided that
M_2/M_1 \sim (D_2/D_1)^3. For the case of N>2 moons, the tidal stability
diagram becomes more complex, revealing a diversity of potential tidal
patterns.


title: Power Law in Firms Bankruptcy

abstract:
  We consider the scaling behaviors for fluctuations of the number of Korean
firms bankrupted in the period from August 1 2002 to October 28 2003. We
observe a power law for the distribution of the number of the bankrupted firms.
The Pareto exponent is close to unity. We also consider the daily increments of
the number of firms bankrupted. The probability distribution of the daily
increments for the firms bankrupted follows the Gaussian distribution in
central part and has a fat tail. The tail parts of the probability distribution
of the daily increments for the firms bankrupted follow a power law.

categories: physics.soc-ph cond-mat.stat-mech physics.gen-ph q-fin.ST


title:
Selective Reflection Spectroscopy on the UV Third Resonance Line of Cs :
  Simultaneous Probing of a van der Waals Atom-Surface Interaction Sensitive to
  Far IR Couplings and of Interatomic Collisions

abstract:
  We report on the analysis of FM selective reflection experiments on the
6S1/2->8P3/2 transition of Cs at 388 nm, and on the measurement of the surface
van der Waals interaction exerted by a sapphire interface on Cs(8P3/2). Various
improvements in the systematic fitting of the experiments have permitted to
supersede the major difficulty of a severe overlap of the hyperfine components,
originating on the one hand in a relatively small natural structure, and on the
other hand on a large pressure broadening imposed by the high atomic density
needed for the observation of selective reflection on a weak transition. The
strength of the van der Waals surface interaction is evaluated to be 73$\pm$10
kHz.$\mu$m3. An evaluation of the pressure shift of the transition is also
provided as a by-product of the measurement. We finally discuss the
significance of an apparent disagreement between the experimental measurement
of the surface interaction, and the theoretical value calculated for an
electromagnetic vacuum at a null temperature. The possible influence of the
thermal excitation of the surface is evoked, because, the dominant
contributions to the vW interaction for Cs(8P3/2) lie in the far infrared
range.


title:
Cascaded generation of multiply charged optical vortices and
  spatiotemporal helical beams in a Raman medium

abstract:
  Using an example of a Raman active medium we describe how a common nonlinear
process of four-wave mixing can be used to induce strong coupling between the
spatial and temporal degrees of freedom in optical waves. This coupling
produces several unexpected effects. Amongst those are cascaded excitation of
multiply charged optical vortices, spatial focusing in a nonlinearly defocusing
medium and generation of helically shaped spatio-temporal optical solitons.


title: Examples of application of mechanics of the inertless mass

abstract:
  These examples are absent in the text of "Mechanics of liquids and gas, or
mechanics of the inertless mass", as it was said in "Foreword of the editor"
(Part I of this monograph). The editor places the missing text separately since
some theoretical and practical positions, including most examples, were
developed by the author himself in two his next investigations. Therefore it
will be more useful to read "The Examples" after all the monographs on
mechanics of the inertless mass, which are in the same archive now. The editor
has no other texts of the author on this subject. "The Examples" are addressed
to specialists in the field of theoretical and practical hydrodynamics and
adjacent sciences.


title:
Self-Compression of High-Intensity Femtosecond Laser Pulses in Low
  Dispersion Regime

abstract:
  Self-compression of femtosecond laser pulses and more than an order of
magnitude increase of the peak intensity is found in a positive dispersion
medium in low dispersion regime based on the (3+1)-dimensional nonlinear
Schr{\"o}dinger equation. A method of high-intensity femtosecond pulse
formation can be developed on that basis.


title: Network Automata: Coupling structure and function in real-world networks

abstract:
  We introduce Network Automata, a framework which couples the topological
evolution of a network to its structure. It is useful for dealing with networks
in which the topology evolves according to some specified microscopic rules
and, simultaneously, there is a dynamic process taking place on the network
that both depends on its structure but is also capable of modifying it. It is a
generic framework for modeling systems in which network structure, dynamics,
and function are interrelated. At the practical level, this framework allows
for easy implementation of the microscopic rules involved in such systems. To
demonstrate the approach, we develop a class of simple biologically inspired
models of fungal growth.


title: Boltzmann's Concept of Reality

abstract:
  In this article we describe and analyze the concept of reality developed by
the Austrian theoretical physicist Ludwig Boltzmann. It is our thesis that
Boltzmann was fully aware that reality could, and actually was, described by
different points of view. In spite of this, Boltzmann did not renounce the idea
that reality is real. We also discuss his main motivations to be strongly
involved with philosophy of science, as well as further developments made by
Boltzmann himself of his main philosophical ideas, namely scientific theories
as images of Nature and its consequences. We end the paper with a discussion
about the modernity of Boltzmann's philosophy of science.

categories: physics.hist-ph gr-qc physics.pop-ph physics.soc-ph


title:
Traffic dynamics of packets generated with non-homogeneously selected
  sources and destinations in scale-free networks

abstract:
  In this paper, we study traffic dynamics in scale-free networks in which
packets are generated with non-homogeneously selected sources and destinations,
and forwarded based on the local routing strategy. We consider two situations
of packet generation: (i) packets are more likely generated at high-degree
nodes; (ii) packets are more likely generated at low-degree nodes. Similarly,
we consider two situations of packet destination: (a) packets are more likely
to go to high-degree nodes; (b) packets are more likely to go to low-degree
nodes. Our simulations show that the network capacity and the optimal value of
$\alpha$ corresponding to the maximum network capacity greatly depend on the
configuration of packets' sources and destinations. In particular, the capacity
is greatly enhanced when most packets travel from low-degree nodes to
high-degree nodes.


title:
Analysis of the Formation of Structures and Chaotic Dynamics in a
  Nonrelativistic Electron Beam with a Virtual Cathode in the Presence of a
  Decelerating Field

abstract:
  A nonrelativistic electron beam with a virtual cathode situated in the diode
gap with a decelerating field is experimentally and theoretically studied. A 1D
model of the electron beam in the presence of a decelerating field is
constructed. Nonlinear nonstationary processes in this system are investigated
by means of numerical analysis of the model. The processes are described and
interpreted with regard to formation and interaction of structures in the
electron flow. The theoretical results are qualitatively confirmed by the
experimental data showing that the system under study can be considered as a
promising controlled source of chaotic oscillations in the microwave range.


title: A quantitative analysis of measures of quality in science

abstract:
  Condensing the work of any academic scientist into a one-dimensional measure
of scientific quality is a difficult problem. Here, we employ Bayesian
statistics to analyze several different measures of quality. Specifically, we
determine each measure's ability to discriminate between scientific authors.
Using scaling arguments, we demonstrate that the best of these measures require
approximately 50 papers to draw conclusions regarding long term scientific
performance with usefully small statistical uncertainties. Further, the
approach described here permits the value-free (i.e., statistical) comparison
of scientists working in distinct areas of science.


title: Speed-gradient principle for nonstationary processes in thermodynamics

abstract:
  The speed-gradient variational principle (SG-principle) is formulated and
applied to thermodynamical systems. It is shown that Prigogine's principle of
minimum entropy production and Onsager's symmetry relations can be interpreted
in terms of the SG-principle and, therefore, are equivalent to each other. In
both cases entropy of the system plays a role of the goal functional. The
speed-gradient formulation of thermodynamic principles provide their extended
versions, describing transient dynamics of nonstationary systems far from
equilibrium. As an example a model of transient (relaxation) dynamics for
maximum entropy principle is derived.


title:
Current-induced break of inversion symmetry in Si: optical
  second-harmonic generation induced by a dc current

abstract:
  The dc-current-induced optical second-harmonic generation is observed at the
surface of centrosymmetric single crystal of Si. Surface dc-current with
density up to $\textit{j}_{max} \sim 10^{3}$ A/cm$^{2}$ results in break of
inversion symmetry of Si and induces optical second-harmonic generation with
intensity that corresponds to the appearance of dipole second-order
susceptibility $\chi^{(2)d}(j_{max})\sim 3 \cdot 10^{-15}$m/V.


title:
Double energy differential cross sections for the Coulomb four-body
  problem in a quasiclassical framework

abstract:
  In a quasiclassical framework, we formulate the double energy differential
cross sections for the Coulomb four-body problem. We present results for the
triple photoionization from the Li ground state at 220.5, 115, 50 and 3.8 eV
excess energies. With the energy of one of the electrons kept fixed, the double
energy differential cross sections at 220.5 and 115 excess energies are found
to be of "U-shape" (unequal energy sharing), with those at 115 eV being in very
good agreement with ab-initio results. At 50 eV, it seems that a transition
starts taking place to more equal energy sharing configurations. Close to
threshold, at 3.8 eV excess energy, the equal energy sharing configurations are
the dominant ones.


title: Evolutionary game dynamics with three strategies in finite populations

abstract:
  We propose a model for evolutionary game dynamics with three strategies $A$,
$B$ and $C$ in the framework of Moran process in finite populations. The model
can be described as a stochastic process which can be numerically computed from
a system of linear equations. Furthermore, to capture the feature of the
evolutionary process, we define two essential variables, the {\em global} and
the {\em local} fixation probability. If the {\em global} fixation probability
of strategy $A$ exceeds the neutral fixation probability, the selection favors
$A$ replacing $B$ or $C$ no matter what the initial ratio of $B$ to $C$ is.
Similarly, if the {\em local} fixation probability of $A$ exceeds the neutral
one, the selection favors $A$ replacing $B$ or $C$ only in some appropriate
initial ratios of $B$ to $C$. Besides, using our model, the famous game with
AllC, AllD and TFT is analyzed. Meanwhile, we find that a single individual TFT
could invade the entire population under proper conditions.


title:
Information propagation and collective consensus in blogosphere: a
  game-theoretical approach

abstract:
  In this paper, we study the information propagation in an empirical blogging
network by game-theoretical approach. The blogging network has small-world
property and is scale-free. Individuals in the blogosphere coordinate their
decisions according to their idiosyncratic preferences and the choices of their
neighbors. We find that corresponding to different initial conditions and
weights, the equilibrium frequency of discussions has a transition from high to
low as a result of the common interest in the topics specified by payoff
matrices. Furthermore, under recommendation, namely, individuals in blogging
networks refer to additional bloggers' resources besides their nearest
neighbors preferentially according to the popularity of the blogs, the whole
blogging network ultrafastly evolves into consensus state (absorbing state).
Our results reflect the dynamic pattern of information propagation in blogging
networks.


title: Evolutionary game dynamics in inhomogeneous populations

abstract:
  To our knowledge, the populations are generally assumed to be homogeneous in
the traditional approach to evolutionary game dynamics. Here, we focus on the
inhomogeneous populations. A simple model which can describe the inhomogeneity
of the populations and a microscopic process which is similar to Moran Process
are presented. By studying the replicator dynamics, it is shown that this model
also keeps the fixed points unchanged and can affect the speed of converging to
the equilibrium state. The fixation probability and the fixation time of this
model are computed and discussed. In the inhomogeneous populations, there are
different situations that characterize the time scale of evolution; and in each
situation, there exists an optimum solution for the time to the equilibrium
points, respectively. Moreover, these results on the speed of evolution are
valid for infinite and finite populations.


title:
Influence of initial distributions on robust cooperation in evolutionary
  Prisoner's Dilemma

abstract:
  We study the evolutionary Prisoner's Dilemma game on scale-free networks for
different initial distributions. We consider three types of initial
distributions for cooperators and defectors: initially random distribution with
different frequencies of defectors; intentional organization with defectors
initially occupying the most connected nodes with different fractions of
defectors; intentional assignment for cooperators occupying the most connected
nodes with different proportions of defectors at the beginning. It is shown
that initial configurations for cooperators and defectors can influence the
stationary level of cooperation and the evolution speed of cooperation.
Organizations with the vertices with highest connectivity representing
individuals cooperators could exhibit the most robust cooperation and drive
evolutionary process to converge fastest to the high steady cooperation in the
three situations of initial distributions. Otherwise, we determine the critical
initial frequencies of defectors above which the extinction of cooperators
occurs for the respective initial distributions, and find that the presence of
network loops and clusters for cooperators can favor the emergence of
cooperation.


title: Scaling laws of turbulent dynamos

abstract:
  We consider magnetic fields generated by homogeneous isotropic and parity
invariant turbulent flows. We show that simple scaling laws for dynamo
threshold, magnetic energy and Ohmic dissipation can be obtained depending on
the value of the magnetic Prandtl number.


title: QED treatment of electron correlation in Li-like ions

abstract:
  A systematic QED treatment of electron correlation is presented for ions
along the lithium isoelectronic sequence. We start with the zeroth-order
approximation that accounts for a part of the electron-electron interaction by
a local model potential introduced into the Dirac equation. The residual
electron correlation is treated by perturbation theory. Rigorous QED evaluation
is presented for the first two terms of the perturbative expansion; the
third-order contribution is calculated within the many-body perturbation
theory. We report accurate numerical results for the electronic-structure part
of the ionization potential for the n=2 states of all Li-like ions up to
uranium.


title:
Scanning Near-Field Optical Coherent Spectroscopy of Single Molecules at
  1.4 Kelvin

abstract:
  We present scanning near-field extinction spectra of single molecules
embedded in a solid matrix. By varying the molecule-tip separation, we modify
the line shape of the spectra, demonstrating the coherent nature of the
interaction between the incident laser light and the excited state of the
molecule. We compare the measured data with the outcome of numerical
calculations and find a very good agreement.


title:
Promotion of cooperation induced by the interplay between structure and
  game dynamics

abstract:
  We consider the coupled dynamics of the adaption of network structure and the
evolution of strategies played by individuals occupying the network vertices.
We propose a computational model in which each agent plays a $n$-round
Prisoner's Dilemma game with its immediate neighbors, after that, based upon
self-interest, partial individuals may punish their defective neighbors by
dismissing the social tie to the one who defects the most times, meanwhile seek
for a new partner at random from the neighbors of the punished agent. It is
found that the promotion of cooperation is attributed to the entangled
evolution of individual strategy and network structure. Moreover, we show that
the emerging social networks exhibit high heterogeneity and disassortative
mixing pattern. For a given average connectivity of the population and the
number of rounds, there is a critical value for the fraction of individuals
adapting their social interactions, above which cooperators wipe out defectors.
Besides, the effects of the average degree, the number of rounds, and the
intensity of selection are investigated by extensive numerical simulations. Our
results to some extent reflect the underlying mechanism promoting cooperation.


title:
Social dilemmas in an online social network: the structure and evolution
  of cooperation

abstract:
  We investigate two paradigms for studying the evolution of
cooperation--Prisoner's Dilemma and Snowdrift game in an online friendship
network obtained from a social networking site. We demonstrate that such social
network has small-world property and degree distribution has a power-law tail.
Besides, it has hierarchical organizations and exhibits disassortative mixing
pattern. We study the evolutionary version of the two types of games on it. It
is found that enhancement and sustainment of cooperative behaviors are
attributable to the underlying network topological organization. It is also
shown that cooperators can survive when confronted with the invasion of
defectors throughout the entire ranges of parameters of both games. The
evolution of cooperation on empirical networks is influenced by various network
effects in a combined manner, compared with that on model networks. Our results
can help understand the cooperative behaviors in human groups and society.


title: The exact Darwin Lagrangian

abstract:
  Darwin (1920) noted that when radiation can be neglected it should be
possible to eliminate the radiation degrees-of-freedom from the action of
classical electrodynamics and keep the discrete particle degrees-of-freedom
only. Darwin derived his well known Lagrangian by series expansion in $v/c$
keeping terms up to order $(v/c)^2$. Since radiation is due to acceleration the
assumption of low speed should not be necessary. A Lagrangian is suggested that
neglects radiation without assuming low speed. It cures deficiencies of the
Darwin Lagrangian in the ultra-relativistic regime.


title:
Maximum power, ecological function and efficiency of an irreversible
  Carnot cycle. A cost and effectiveness optimization

abstract:
  In this work we include, for the Carnot cycle, irreversibilities of linear
finite rate of heat transferences between the heat engine and its reservoirs,
heat leak between the reservoirs and internal dissipations of the working
fluid. A first optimization of the power output, the efficiency and ecological
function of an irreversible Carnot cycle, with respect to: internal temperature
ratio, time ratio for the heat exchange and the allocation ratio of the heat
exchangers; is performed. For the second and third optimizations, the optimum
values for the time ratio and internal temperature ratio are substituted into
the equation of power and, then, the optimizations with respect to the cost and
effectiveness ratio of the heat exchangers are performed. Finally, a criterion
of partial optimization for the class of irreversible Carnot engines is herein
presented.


title:
Experimental evidence for phase synchronization transitions in human
  cardio-respiratory system

abstract:
  Transitions in the dynamics of complex systems can be characterized by
changes in the synchronization behavior of their components. Taking the human
cardio-respiratory system as an example and using an automated procedure for
screening the synchrograms of 112 healthy subjects we study the frequency and
the distribution of synchronization episodes under different physiological
conditions that occur during sleep. We find that phase synchronization between
heartbeat and breathing is significantly enhanced during non-rapid-eye-movement
(non-REM) sleep (deep sleep and light sleep) and reduced during REM sleep. Our
results suggest that the synchronization is mainly due to a weak influence of
the breathing oscillator upon the heartbeat oscillator, which is disturbed in
the presence of long-term correlated noise, superimposed by the activity of
higher brain regions during REM sleep.


title: On the quality of the Olmec mirrors and its utilization

abstract:
  Archaeological mirrors from the Olmec civilization were analyzed in the
context of bibliography produced in the last two decades. Photographs of its
images are showed as a proof of its good quality. Some suggestions are made on
its probable utilization.


title: Olmec mirrors: an example of archaeological American mirrors

abstract:
  Archaeological mirrors from the Olmec civilization are described according to
bibliographic references and to personal observations and photographs.


title:
Influence of the pinhole size on the resolution of the 4Pi' microscope
  studied by means of the optical transfer function

abstract:
  Optical transfer functions are presented for the 4pi' microscope. The effects
of the size of the confocal pinhole on the three-dimensional resolution are
studied. It is shown that the resolution of the 4Pi' microscope depends weakly
on the pinhole size. This result suggest that the pinhole can be removed in
order to increase the signal-to-noise ratio.


title:
Central universal force field to explain solar orbital radial
  acceleration and other universal phenomena

abstract:
  I investigate a repulsive central universal force field on the behavior of
celestial objects. I show its negative tidal effect on the solar orbits as
experienced by Pioneer spacecrafts. I explain several cosmological effects in
light of this force.


title:
Intramolecular vibrational energy redistribution as state space
  diffusion: Classical-quantum correspondence

abstract:
  We study the intramolecular vibrational energy redistribution (IVR) dynamics
of an effective spectroscopic Hamiltonian describing the four coupled high
frequency modes of CDBrClF. The IVR dynamics ensuing from nearly isoenergetic
zeroth-order states, an edge (overtone) and an interior (combination) state, is
studied from a state space diffusion perspective. A wavelet based
time-frequency analysis reveals an inhomogeneous phase space due to the
trapping of classical trajectories. Consequently the interior state has a
smaller effective IVR dimension as compared to the edge state.


title:
Dynamics of charge-displacement channeling in intense laser-plasma
  interactions

abstract:
  The dynamics of transient electric fields generated by the interaction of
high intensity laser pulses with underdense plasmas has been studied
experimentally with the proton projection imaging technique. The formation of a
charged channel, the propagation of its front edge and the late electric field
evolution have been characterised with high temporal and spatial resolution.
Particle-in-cell simulations and an electrostatic, ponderomotive model
reproduce the experimental features and trace them back to the ponderomotive
expulsion of electrons and the subsequent ion acceleration.


title:
Local Convergence and Global Diversity: The Robustness of Cultural
  Homophily

abstract:
  Recent extensions of the Axelrod model of cultural dissemination (Klemm et al
2003) showed that global diversity is extremely fragile with small amounts of
cultural mutation. This seemed to undermine the original Axelrod theory that
homophily preserves diversity. We show that cultural diversity is surprisingly
robust if we increase the tendency towards homophily as follows. First, we
raised the threshold of similarity below which influence is precluded. Second,
we allowed agents to be influenced by all neighbors simultaneously, instead of
only one neighbor as assumed in the orginal model. Computational experiments
show how both modifications strongly increase the robustness of diversity
against mutation. We also find that our extensions may reverse at least one of
the main results of Axelrod. While Axelrod predicted that a larger number of
cultural dimensions (features) reduces diversity, we find that more features
may entail higher levels of diversity.


title:
Stability Dust-Ion-Acoustic Wave in Dusty Plasmas With Stream -Influence
  of Charge Fluctuation of Dust Grains

abstract:
  There is a quickly increasing wealth of experimental data on so-called dusty
plasmas i. e. ionized gases or usual plasmas that contain micron sized charged
particles. Interest in these structures is driven both by their importance in
many astrophysical as well as commercial situations. Among them are linear and
nonlinear wave phenomena. We consider the influence of dust charge fluctuations
on stability of the ion-acoustic waves when the stream of particles is present.
It is assumed that all grains of dust have equal masses but charges are not
constant in time-they may fluctuate in time. The dust charges are not really
independent of the variations of the plasma potentials. All modes will
influence the charging mechanism, and feedback will lead to several new
interesting and unexpected phenomena. The charging of the grains depends on
local plasma characteristics. If the waves disturb these characteristic, then
charging of the grains is affected and the grain charge is modified, with a
resulting feedback on the wave mode. In case considering here, when temperature
of electrons is much greater then the temperature of the ions and temperature
of electrons is not great enough for further ionization of the ions, we show
that stability of the acoustic wave depends only one phenomenological
coefficient.


title:
Diffusive behavior and the modeling of characteristic times in limit
  order executions

abstract:
  We present an empirical study of the first passage time (FPT) of order book
prices needed to observe a prescribed price change Delta, the time to fill
(TTF) for executed limit orders and the time to cancel (TTC) for canceled ones
in a double auction market. We find that the distribution of all three
quantities decays asymptotically as a power law, but that of FPT has
significantly fatter tails than that of TTF. Thus a simple first passage time
model cannot account for the observed TTF of limit orders. We propose that the
origin of this difference is the presence of cancellations. We outline a simple
model, which assumes that prices are characterized by the empirically observed
distribution of the first passage time and orders are canceled randomly with
lifetimes that are asymptotically power law distributed with an exponent
lambda_LT. In spite of the simplifying assumptions of the model, the inclusion
of cancellations is enough to account for the above observations and enables
one to estimate characteristics of the cancellation strategies from empirical
data.


title:
Charge Fluctuation of Dust Grain and Its Impact on Dusty-Acoustic Wave
  Damping

abstract:
  We consider the influence of dust charge fluctuations on damping of the
dust-ion-acoustic waves. It is assumed that all grains have equal masses but
charges are not constant in time - they may fluctuate in time. The dust charges
are not really independent of the variations in the plasma potentials. All
modes will influence the charging mechanism, and feedback will lead to several
new interesting and unexpected phenomena. The charging of the grains depends on
local plasma characteristics. If the waves disturb these characteristic, then
charging of the grains is affected and the grain charge is modified, with a
resulting feedback on the wave mode. In the case considered here, when the
temperature of electrons is much greater than the temperature of the ions and
the temperature of electrons is not great enough for further ionization of the
ions, we show that attenuation of the acoustic wave depends only on one
phenomenological coefficient


title: The dynamics of transition to turbulence in plane Couette flow

abstract:
  In plane Couette flow, the incompressible fluid between two plane parallel
walls is driven by the motion of those walls. The laminar solution, in which
the streamwise velocity varies linearly in the wall-normal direction, is known
to be linearly stable at all Reynolds numbers ($Re$). Yet, in both experiments
and computations, turbulence is observed for $Re \gtrsim 360$.
  In this article, we show that for certain {\it threshold} perturbations of
the laminar flow, the flow approaches either steady or traveling wave
solutions. These solutions exhibit some aspects of turbulence but are not fully
turbulent even at $Re=4000$. However, these solutions are linearly unstable and
flows that evolve along their unstable directions become fully turbulent. The
solution approached by a threshold perturbation could depend upon the nature of
the perturbation. Surprisingly, the positive eigenvalue that corresponds to one
family of solutions decreases in magnitude with increasing $Re$, with the rate
of decrease given by $Re^{\alpha}$ with $\alpha \approx -0.46$.


title: From a toy model to the double square root voting system

abstract:
  We investigate systems of indirect voting based on the law of Penrose, in
which each representative in the voting body receives the number of votes
(voting weight) proportional to the square root of the population he or she
represents. For a generic population distribution the quota required for the
qualified majority can be set in such a way that the voting power of any state
is proportional to its weight. For a specific distribution of population the
optimal quota has to be computed numerically. We analyse a toy voting model for
which the optimal quota can be estimated analytically as a function of the
number of members of the voting body. This result, combined with the normal
approximation technique, allows us to design a simple, efficient, and flexible
voting system which can be easily adopted for varying weights and number of
players.


title: Accelerating networks

abstract:
  Evolving out-of-equilibrium networks have been under intense scrutiny
recently. In many real-world settings the number of links added per new node is
not constant but depends on the time at which the node is introduced in the
system. This simple idea gives rise to the concept of accelerating networks,
for which we review an existing definition and -- after finding it somewhat
constrictive -- offer a new definition. The new definition provided here views
network acceleration as a time dependent property of a given system, as opposed
to being a property of the specific algorithm applied to grow the network. The
defnition also covers both unweighted and weighted networks. As time-stamped
network data becomes increasingly available, the proposed measures may be
easily carried out on empirical datasets. As a simple case study we apply the
concepts to study the evolution of three different instances of Wikipedia,
namely, those in English, German, and Japanese, and find that the networks
undergo different acceleration regimes in their evolution.


title: E.C.G. Stueckelberg: a forerunner of modern physics

abstract:
  The pioneering work of E.C.G. Stueckelberg is briefly analyzed: the formalism
of the Stueckelberg field, able to describe a massive vector field, is
reviewed, and some applications are presented. In particular, starting from his
very first application, devoted to describe nuclear phenomena known in the
Thirties, later attempts to demonstrate the renormalizability of the model are
considered. Finally, also string theory and LQG are illustrated to be a
suitable scenario for the Stueckelberg field.


title:
Study of a Plane Free Jet Exhausting from a Channel by Vortex in Cell
  Method

abstract:
  A two-dimensional simulation of a plane jet exhausting from a channel has
been performed using the vortex in cell algorithm in the Reynolds number range
of 100 to 900. The vorticity is generated on the wall of the entrance channel
whose length has been fixed in order to obtain a fully developed velocity
profile at the entry of the jet. The transient behaviour of the velocity field
starting from rest has been observed until reaching a quasi steady regime. The
mean value of the velocity field is compared with the results of a finite
volume computation on the same mesh. The velocity fluctuations obtained using
this method are analysed. Their effect on the mean flow is estimated to be
smaller than the viscous effect.


title: Electron-based crystalline undulator

abstract:
  We discuss the features of a crystalline undulator of the novel type based on
the effect of a planar channeling of ultra-relativistic electrons in a
periodically bent crystals. It is demonstrated that an electron-based undulator
is feasible in the tens of GeV range of the beam energies, which is noticeably
higher than the energy interval allowed in a positron-based undulator.
Numerical analysis of the main parameters of the undulator as well as the
characteristics of the emitted undulator radiation is carried out for 20 and 50
GeV electrons channeling in diamond and silicon crystals along the (111)
crystallographic planes.


title:
Noncontact atomic force microscopy simulator with phase-locked-loop
  controlled frequency detection and excitation

abstract:
  A simulation of an atomic force microscope operating in the constant
amplitude dynamic mode is described. The implementation mimics the electronics
of a real setup including a digital phase-locked loop (PLL). The PLL is not
only used as a very sensitive frequency detector, but also to generate the
time-dependent phase shifted signal driving the cantilever. The optimum
adjustments of individual functional blocks and their joint performance in
typical experiments are determined in detail. Prior to testing the complete
setup, the performances of the numerical PLL and of the amplitude controller
were ascertained to be satisfactory compared to those of the real components.
Attention is also focused on the issue of apparent dissipation, that is, of
spurious variations in the driving amplitude caused by the nonlinear
interaction occurring between the tip and the surface and by the finite
response times of the various controllers. To do so, an estimate of the minimum
dissipated energy that is detectable by the instrument upon operating
conditions is given. This allows us to discuss the relevance of apparent
dissipation that can be conditionally generated with the simulator in
comparison to values reported experimentally. The analysis emphasizes that
apparent dissipation can contribute to the measured dissipation up to 15% of
the intrinsic dissipated energy of the cantilever interacting with the surface,
but can be made negligible when properly adjusting the controllers, the PLL
gains and the scan speed. It is inferred that the experimental values of
dissipation usually reported in the literature cannot only originate in
apparent dissipation, which favors the hypothesis of "physical" channels of
dissipation.


title:
A Physics Show Performed by Students for Kids: From Mechanics to
  Elementary Particle Physics

abstract:
  We describe an initiative at the University of Bonn, where the students
develop and perform a 2 hour physics show for school classes and the general
public. The show is entertaining and educational and is aimed at children aged
10 and older. For the physics students this is a unique experience to apply
their knowledge at an early stage and gives them the chance to develop skills
in the public presentation of science, in front of 520 people per show. We have
extended the activity to put on an elementary particle physics show for
teenagers. Furthermore, local high schools have picked up the idea; their
students put on similar shows for fellow students and parents. We would be
interested in hearing about related activities elsewhere.

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


title:
On the changes in number and intensity of North Atlantic tropical
  cyclones

abstract:
  Bayesian statistical models were developed for the number of tropical
cyclones and the rate at which these cyclones became hurricanes in the North
Atlantic. We find that, controlling for the cold tongue index and the North
Atlantic oscillation index, there is high probability that the number of
cyclones has increased in the past thirty years; but the rate at which these
storms become hurricanes appears to be constant. We also investigate storm
intensity by measuring the distribution of individual storm lifetime in days,
storm track length, and Emanuel's power dissiptation index. We find little
evidence that the distribution of individual storm intensity is changing
through time. Any increase in cumulative yearly storm intensity and potential
destructiveness, therefore, is due to the increasing number of storms and not
due to any increase in the intensity of individual storms.


title: String model of the Hydrogen Atom

abstract:
  A non-moving electron hydrogen model is proposed, resolving a long standing
contradiction (94 years) in the hydrogen atom. This, however, forces to not use
the "in an orbit point particle kinetic energy" as the phenomenon responsible
for the atom stability. The repulsion between the masses of the electron and
proton is what is responsible of such stability. The mass of the electron is a
field fully described by the uncertainty principle through the confinement of
the particle, which is also consistent with the general theory of relativity
that states: "mass-energy tells the space how to bend". Ergo, mass exerts a
tension on its surrounding space and the lighter the mass the larger the space
it will occupy. Based on this concept it is proposed that the orbital is the
electron. The electron's orbitals are just the electron's different ways of
intersecting the space; with different magnetic momenta. The coupling of this
momenta with the magnetic moment of the proton finally explains the hyperfine
structure of the hydrogen spectrum with an overwhelming simplicity


title: Statistical Geometry of Gravitation

abstract:
  General Relativity explains with precision the anomalous advance of the
perihelion of Mercury, discovered by Le Verrier in 1859. Otherwise, diverse
post-Newtonian proposals trying to solve this anomaly, introduce mathematical
potentials focused on a finite propagation speed.
  This paper tries to set some properties that should have any hypothetical
gravitational potential suitable with material objects inside a physical
universe. If a propagation speed is admitted, this assumption must link its
origin, the continuous update, the trajectory, the retarded action and impulse
mechanism (transit action) in the final target.
  This gravitational potential, tries to explain the anomalous shift of the
perihelion of Mercury. Otherwise, applied as a potential of force added to a
mechanical momentum, could give a partial explanation of the anomalous
acceleration of Pioneer 10/11. Anyway, it is an hypothetical conjecture without
any proof of its physical reality


title: Deterministic Modularity Optimization

abstract:
  We study community structure of networks. We have developed a scheme for
maximizing the modularity Q based on mean field methods. Further, we have
defined a simple family of random networks with community structure; we
understand the behavior of these networks analytically. Using these networks,
we show how the mean field methods display better performance than previously
known deterministic methods for optimization of Q.


title: Growing Trees in Internet News Groups and Forums

abstract:
  We present an empirical study of the networks created by users within
internet news groups and forums and show that they organise themselves into
scale-free trees. The structure of these trees depends on the topic under
discussion; specialist topics have trees with a short shallow structure whereas
more universal topics are discussed widely and have a deeper tree structure.
For news groups we find that the distribution of the time intervals between
when a message is posted and when it receives a response exhibits a composite
power-law behaviour. From our statistics we can see if the news group or forum
is free or is overseen by a moderator. The correlation function of activity,
the number of messages posted in a given time, shows long range correlations
connected with the users' daily routines. The distribution of distances between
each message and its root is exponential for most news groups and power-law for
the forums. For both formats we find that the relation between the supremacy
(the total number of nodes that are \emph{under} the node $i$, including node
$i$) and the degree is linear $s(k)\sim k$, in contrast to the analytical
relation for Barab\'{a}si-Albert network.


title:
Betweenness Centrality of Fractal and Non-Fractal Scale-Free Model
  Networks and Tests on Real Networks

abstract:
  We study the betweenness centrality of fractal and non-fractal scale-free
network models as well as real networks. We show that the correlation between
degree and betweenness centrality $C$ of nodes is much weaker in fractal
network models compared to non-fractal models. We also show that nodes of both
fractal and non-fractal scale-free networks have power law betweenness
centrality distribution $P(C)\sim C^{-\delta}$. We find that for non-fractal
scale-free networks $\delta = 2$, and for fractal scale-free networks $\delta =
2-1/d_{B}$, where $d_{B}$ is the dimension of the fractal network. We support
these results by explicit calculations on four real networks: pharmaceutical
firms (N=6776), yeast (N=1458), WWW (N=2526), and a sample of Internet network
at AS level (N=20566), where $N$ is the number of nodes in the largest
connected component of a network. We also study the crossover phenomenon from
fractal to non-fractal networks upon adding random edges to a fractal network.
We show that the crossover length $\ell^{*}$, separating fractal and
non-fractal regimes, scales with dimension $d_{B}$ of the network as
$p^{-1/d_{B}}$, where $p$ is the density of random edges added to the network.
We find that the correlation between degree and betweenness centrality
increases with $p$.


title:
Perfect energy transfer and mean-eddy interaction in incompressible
  fluid flows

abstract:
  The mean-eddy interaction in a flow is investigated in terms of the energy
transfer between its mean and eddy processes. In a Reynolds decomposition
framework, energy transfer can be defined from the decomposed energy equations,
but the definition is subjective with the classical energetics formalism. This
paper shows that a faithful formalism can be rigorously established within the
same framework. The resulting transfer sums to zero everywhere over the
decomposed subspaces, representing a mere redistribution of energy between the
mean and eddy processes, without generating or destroying energy as a whole.
For this reason, it has been referred to as perfect transfer in distinction
from other energy transfers one may have encountered. The perfect transfer has
a simple form in expression, with the introduction of an eddy flow coupled with
the mean and eddy processes of the field under concern. The eddy or turbulence
production is then totally determined by the divergence of this flow. This
formalism has been validated with a well-known barotropic instability model,
and a wake control problem. It is expected to be useful for the harnessing of
turbulence, in that it may help to identify the best locations to place passive
controls, or design the performance functional for active controls.


title:
Waiting time analysis of foreign currency exchange rates: Beyond the
  renewal-reward theorem

abstract:
  We evaluate the average waiting time between observing the price of financial
markets and the next price change, especially in an on-line foreign exchange
trading service for individual customers via the internet. Basic technical idea
of our present work is dependent on the so-called renewal-reward theorem.
Assuming that stochastic processes of the market price changes could be
regarded as a renewal process, we use the theorem to calculate the average
waiting time of the process. In the conventional derivation of the theorem, it
is apparently hard to evaluate the higher order moments of the waiting time. To
overcome this type of difficulties, we attempt to derive the waiting time
distribution Omega(s) directly for arbitrary time interval distribution (first
passage time distribution) of the stochastic process P_{W}(tau) and observation
time distribution P_{O}(t) of customers. Our analysis enables us to evaluate
not only the first moment (the average waiting time) but also any order of the
higher moments of the waiting time. Moreover, in our formalism, it is possible
to model the observation of the price on the internet by the customers in terms
of the observation time distribution P_{O}(t). We apply our analysis to the
stochastic process of the on-line foreign exchange rate for individual
customers from the Sony bank and compare the moments with the empirical data
analysis.


title: New insights into pedestrian flow through bottlenecks

abstract:
  Capacity estimation is an important tool for the design and dimensioning of
pedestrian facilities. The literature contains different procedures and
specifications which show considerable differences with respect to the
estimated flow values. Moreover do new experimental data indicate a stepwise
growing of the capacity with the width and thus challenge the validity of the
specific flow concept. To resolve these differences we have studied
experimentally the unidirectional pedestrian flow through bottlenecks under
laboratory conditions. The time development of quantities like individual
velocities, density and individual time gaps in bottlenecks of different width
is presented. The data show a linear growth of the flow with the width. The
comparison of the results with experimental data of other authors indicates
that the basic assumption of the capacity estimation for bottlenecks has to be
revised. In contradiction with most planning guidelines our main result is,
that a jam occurs even if the incoming flow does not overstep the capacity
defined by the maximum of the flow according to the fundamental diagram.


title:
Electron Scattering from Gaseous Ocs($^1\Sigma$): Comparing Computed
  Angular Distributions and Elastic Cross Sections with Experiments

abstract:
  Differential cross sections are computed for the title polar molecule using
static interaction, exchange forces and correlation-polarisation effects as
described in detail in the main text. The dipole effect is also reported via
the dipole Born correction procedure and the final angular distributions are
compared with existing experimental data. The shape and location of the
prominent low-energy resonance are computed and compared with experiments. The
comparison shows that the present treatment of the interaction forces and of
the quantum dynamics can indeed afford good agreement between measured and
computed quantities for a multielectron target as OCS.


title:
Comment on "Large negative lateral shifts from the Kretschmann-Raether
  configuration with left-handed materials" Appl. Phys. Lett. 87, 221102, 2005

abstract:
  The negative shifts seen by Wang and Zhu are not due to the excitation of
surface plasmons but to leaky modes of the slab propagating backward. Provided
the characteristics of the LHM slab are chosen correctly, it is shown that a
leaky surface plasmon can actually be excited using the KR configuration.


title:
Single-cycle megawatt terahertz pulse generation from a wavelength-scale
  plasma oscillator driven by ultrashort laser pulses

abstract:
  The tremendous applications of terahertz (THz) spectroscopy and imaging
require THz sources in different parameters. We propose a novel scheme to
generate single-cycle powerful THz pulses by ultrashort intense laser pulses
incident obliquely on a tenuous plasma slab of few THz wavelengths in
thickness. This is made possible by driving a large amplitude electron plasma
wave in the plasma slab, thus producing a net transient current at the plasma
surfaces. Theory and simulations show that such a THz source is capable of
providing megawatt power and field strength of MV/cm, which may open up new
horizons for nonlinear THz science and applications.


title:
Wave packet dynamics in triplet states of Na2 attached to helium
  nanodroplets

abstract:
  The dynamics of vibrational wave packets excited in Na2 dimers in the triplet
ground and excited states is investigated by means of helium nanodroplet
isolation (HENDI) combined with femtosecond pump-probe spectroscopy. Different
pathways in the employed resonant multi-photon ionization scheme are
identified. Within the precision of the method, the wave packet dynamics
appears to be unperturbed by the helium droplet environment.


title: Comment on "Taleyarkhan et al. Reply:"

abstract:
  In their Reply to my previous Comment, Taleyarkhan and coauthors measure
their detectors' responses to a Cf-252 source, concluding that the resulting
spectra differ substantially from the cavitation-fusion spectra published
earlier in their Letter. On the contrary, I conclude that the two data sets are
qualitatively consistent.

categories: physics.gen-ph nucl-ex nucl-th physics.data-an


title: Link-Space and Network Analysis

abstract:
  Many networks contain correlations and often conventional analysis is
incapable of incorporating this often essential feature. In arXiv:0708.2176, we
introduced the link-space formalism for analysing degree-degree correlations in
evolving networks. In this extended version, we provide additional mathematical
details and supplementary material.
  We explore some of the common oversights when these correlations are not
taken into account, highlighting the importance of the formalism. The formalism
is based on a statistical description of the fraction of links l_{i,j}
connecting nodes of degrees i and j. To demonstrate its use, we apply the
framework to some pedagogical network models, namely, random-attachment,
Barabasi-Albert preferential attachment and the classical Erdos and Renyi
random graph. For these three models the link-space matrix can be solved
analytically. We apply the formalism to a simple one-parameter growing network
model whose numerical solution exemplifies the effect of degree-degree
correlations for the resulting degree distribution. We also employ the
formalism to derive the degree distributions of two very simple network decay
models, more specifically, that of random link deletion and random node
deletion. The formalism allows detailed analysis of the correlations within
networks and we also employ it to derive the form of a perfectly
non-assortative network for arbitrary degree distribution.


title:
An Application of Reversible Entropic Dynamics on Curved Statistical
  Manifolds

abstract:
  Entropic Dynamics (ED) is a theoretical framework developed to investigate
the possibility that laws of physics reflect laws of inference rather than laws
of nature. In this work, a RED (Reversible Entropic Dynamics) model is
considered. The geometric structure underlying the curved statistical manifold,
M is studied. The trajectories of this particular model are hyperbolic curves
(geodesics) on M. Finally, some analysis concerning the stability of these
geodesics on M is carried out.

categories: physics.class-ph cond-mat.stat-mech gr-qc math-ph math.MP physics.gen-ph


title: The Theory Of Matter in Indian Physics

abstract:
  This paper is the second in series of the Indian physics of the
Nyaya-Vaisheshika school. It is significant that the school defines matter not
in terms of something gross that is anchored to the commonsensical notion of an
object, but rather in terms of something that has attributes associated with
it. Matter, or padartha, is whatever is knowable within the overarching complex
of space and time, each of which is taken to be continuous and infinite. The
significant concepts discussed here include how to localize an object, and that
of nothingness, that is, vacuum.


title: Interfacing Collective Atomic Excitations and Single Photons

abstract:
  We study the performance and limitations of a coherent interface between
collective atomic states and single photons. A quantized spin-wave excitation
of an atomic sample inside an optical resonator is prepared probabilistically,
stored, and adiabatically converted on demand into a sub-Poissonian photonic
excitation of the resonator mode. The measured peak single-quantum conversion
efficiency of 0.84(11) and its dependence on various parameters are well
described by a simple model of the mode geometry and multilevel atomic
structure, pointing the way towards implementing high-performance stationary
single-photon sources.


title:
Simple Derivation of Schwarzschild, Lense-Thirring, Reissner-Nordstrom,
  Kerr and Kerr-Newman Metrics

abstract:
  An effort has been made, in order to derive without "hard" mathematics, the
forms of Schwarzschild, Lense-Thirring, Reissner-Nordstrom, Kerr and
Kerr-Newman metrics.


title: Size reduction of complex networks preserving modularity

abstract:
  The ubiquity of modular structure in real-world complex networks is being the
focus of attention in many trials to understand the interplay between network
topology and functionality. The best approaches to the identification of
modular structure are based on the optimization of a quality function known as
modularity. However this optimization is a hard task provided that the
computational complexity of the problem is in the NP-hard class. Here we
propose an exact method for reducing the size of weighted (directed and
undirected) complex networks while maintaining invariant its modularity. This
size reduction allows the heuristic algorithms that optimize modularity for a
better exploration of the modularity landscape. We compare the modularity
obtained in several real complex-networks by using the Extremal Optimization
algorithm, before and after the size reduction, showing the improvement
obtained. We speculate that the proposed analytical size reduction could be
extended to an exact coarse graining of the network in the scope of real-space
renormalization.

categories: physics.comp-ph cond-mat.other cs.DM physics.data-an q-bio.QM


title:
On the electromagnetic momentum of static charge and steady current
  distributions

abstract:
  Faraday's and Furry's formulas for the electromagnetic momentum of static
charge distributions combined with steady electric current distributions are
generalised in order to obtain full agreement with Poynting's formula in the
case where all fields are of class C^1, i.e., continuous and continuously
differentiable, and the integration volume is of finite or infinite extent.
  These three formulas are further generalised to the case where singularities
are allowed to exist at isolated points in the fields, and at surfaces
separating domains in which the distributions are of class C^1.
  Applications are made to electric and magnetic, point-like and finite dipolar
systems, with an emphasis on the impact of singularities on the magnitude and
location of the electromagnetic momentum.


title:
Participation costs dismiss the advantage of heterogeneous networks in
  evolution of cooperation

abstract:
  Real social interactions occur on networks in which each individual is
connected to some, but not all, of others. In social dilemma games with a fixed
population size, heterogeneity in the number of contacts per player is known to
promote evolution of cooperation. Under a common assumption of positively
biased payoff structure, well-connected players earn much by playing
frequently, and cooperation once adopted by well-connected players is
unbeatable and spreads to others. However, maintaining a social contact can be
costly, which would prevent local payoffs from being positively biased. In
replicator-type evolutionary dynamics, it is shown that even a relatively small
participation cost extinguishes the merit of heterogeneous networks in terms of
cooperation. In this situation, more connected players earn less so that they
are no longer spreaders of cooperation. Instead, those with fewer contacts win
and guide the evolution. The participation cost, or the baseline payoff, is
irrelevant in homogeneous populations but is essential for evolutionary games
on heterogeneous networks.


title:
New electron source concept for single-shot sub-100 fs electron
  diffraction in the 100 keV range

abstract:
  We present a method for producing sub-100 fs electron bunches that are
suitable for single-shot ultrafast electron diffraction experiments in the 100
keV energy range. A combination of analytical results and state-of-the-art
numerical simulations show that it is possible to create 100 keV, 0.1 pC, 20 fs
electron bunches with a spotsize smaller than 500 micron and a transverse
coherence length of 3 nm, using established technologies in a table-top set-up.
The system operates in the space-charge dominated regime to produce
energy-correlated bunches that are recompressed by established radio-frequency
techniques. With this approach we overcome the Coulomb expansion of the bunch,
providing an entirely new ultrafast electron diffraction source concept.


title: Octonionic Quantum Interplays of Dark Matter and Ordinary Matter

abstract:
  Based on the electromagnetic interaction and gravitational interaction, the
quantum interplays of the ordinary matter and the dark matter in the octonion
space are discussed. The paper presents the quantization of the particles of
ordinary matter and dark matter, including the quantization of the
electromagnetic field and gravitational field etc. In the electromagnetic and
gravitational interactions, it deduces some predictions of the field source
particle, which are consistent with the Dirac equation and Schrodinger equation
in the quantum mechanics. The researches show that there exist some quantum
characteristics of the intermediate particle in the electromagnetic and
gravitational interactions, including the Dirac-like equation etc.


title: DNA Looping Kinetics Analyzed Using Diffusive Hidden Markov Model

abstract:
  Tethered particle experiments use light microscopy to measure the position of
a micrometer-sized bead tethered to a microscope slide via a ~micrometer length
polymer, in order to infer the behavior of the invisible polymer. Currently,
this method is used to measure rate constants of DNA loop formation and
breakdown mediated by repressor protein that binds to the DNA. We report a new
technique for measuring these rates using a modified hidden Markov analysis
that directly incorporates the diffusive motion of the bead, which is an
inherent complication of tethered particle motion because it occurs on a time
scale between the sampling frequency and the looping time. We compare looping
lifetimes found with our method, which are consistent over a range of sampling
frequencies, to those obtained via the traditional threshold-crossing analysis,
which vary depending on how the raw data are filtered in the time domain. Our
method does not involve such filtering, and so can detect short-lived looping
events and sudden changes in looping behavior.


title:
Comment on "Chebyshev finite difference method for the effects of
  variable viscosity and variable thermal conductivity on heat transfer to a
  micro-polar fluid from a non-isothemal stretching sheet with suction and
  blowing," by S.N. Odda and A.M. Farhan

abstract:
  In the paper [Chaos, Solitons & Fractals, 2006, vol. 30, pp. 851-858]the
authors treat the boundary layer flow of a micropolar fluid along a horizontal
flat plate with blowing or suction. The fluid viscosity and thermal
conductivity are assumed functions of temperature. The boundary layer equations
are transformed into ordinary ones and subsequently are solved using the
Chebyshev finite difference method. However, there are some deficiencies and
errors in this paper.


title:
Comment on Radiation effects on a certain MHD free convection flow, by
  A. Y. Ghaly and on Chebyshev finite difference method for the effects of
  chemical reaction, heat and mass transfer on laminar flow along a semi
  infinite horizontal plate with temperature dependent viscosity, by A.Y. Ghaly
  and M.A. Seddeek

abstract:
  In the above paper [Chaos, Solitons & Fractals, 13 (2002) 1843-1850] the
author treats the boundary layer flow along a vertical isothermal plate of an
electrically conducting fluid. The plate lies in a vertical free stream of
constant velocity $u_\infty$, constant temperature $T_\infty$ and constant mass
concentration $C_\infty$. The plate moves vertically with a velocity which is a
linear function of distance $x$ ($u_w=cx$). A transverse magnetic field with
constant strength $B_0$ is imposed on the flow. The boundary layer equations
are integrated numerically. However, there is a fundamental error in this paper
and the presented results do not have any practical value.


title: A sharp stability criterion for the Vlasov-Maxwell system

abstract:
  We consider the linear stability problem for a 3D cylindrically symmetric
equilibrium of the relativistic Vlasov-Maxwell system that describes a
collisionless plasma. For an equilibrium whose distribution function decreases
monotonically with the particle energy, we obtained a linear stability
criterion in our previous paper. Here we prove that this criterion is sharp;
that is, there would otherwise be an exponentially growing solution to the
linearized system. Therefore for the class of symmetric Vlasov-Maxwell
equilibria, we establish an energy principle for linear stability. We also
treat the considerably simpler periodic 1.5D case. The new formulation
introduced here is applicable as well to the nonrelativistic case, to other
symmetries, and to general equilibria.


title: Optica Precolombina Del Peru

abstract:
  Archaeological American mirrors are common findings and the images obtained
with them are often described by archaeologists as possessing high quality.
However, photographs attesting this fact are rare, if any. To the best of my
knowledge, only two papers show that quality concerning the Olmeca culture, and
only one of them mentions the pre-Inca cultures case. Certainly more images are
needed to increase awareness of the importance of the existence of
sophisticated imaging elements, particularly when evaluating the cultural
degree of the pre-Columbian civilizations. In this paper we show images made in
two museums in Lima, Peru, by means of mirrors and the lens action on a
necklace element.


title: Bright Source of Cold Ions for Surface-Electrode Traps

abstract:
  We produce large numbers of low-energy ions by photoionization of
laser-cooled atoms inside a surface-electrode-based Paul trap. The
isotope-selective trap loading rate of $4\times10^{5}$ Yb$^{+}$ ions/s exceeds
that attained by photoionization (electron impact ionization) of an atomic beam
by four (six) orders of magnitude. Traps as shallow as 0.13 eV are easily
loaded with this technique. The ions are confined in the same spatial region as
the laser-cooled atoms, which will allow the experimental investigation of
interactions between cold ions and cold atoms or Bose-Einstein condensates.


title:
Density functional calculations for stability of Titanium-doped Gold
  clusters AunTi (n=2-16)

abstract:
  The stability and structures of Titanium-doped Gold clusters AunTi (n=2-16)
are studied under the relativistic all-electron density-functional
calculations. It is found that the most stable structures of AunTi clusters
with n=2-7 are planar. A structural transition of AunTi clusters from
two-dimensional to three-dimensional geometry occurs at n=8, while the AunTi
(n=12-16) prefer gold cage structure with Ti atom locating at the center. The
size-dependence of cluster properties such as binding energy, energy gaps,
ionization potentials, and electron affinities have been calculated and
analyzed. The Au14Ti cluster is found to have special stability, which may be
due to the electron shell effects. Further calculations are performed to study
cluster-cluster interaction between two Au14Ti clusters.


title:
A two-Factor Asset Pricing Model and the Fat Tail Distribution of Firm
  Sizes

abstract:
  In the standard equilibrium and/or arbitrage pricing framework, the value of
any asset is uniquely specified from the belief that only the systematic risks
need to be remunerated by the market. Here, we show that, even for arbitrary
large economies when the distribution of the capitalization of firms is
sufficiently heavy-tailed as is the case of real economies, there may exist a
new source of significant systematic risk, which has been totally neglected up
to now but must be priced by the market. This new source of risk can readily
explain several asset pricing anomalies on the sole basis of the
internal-consistency of the market model. For this, we derive a theoretical
two-factor model for asset pricing which has empirically a similar explanatory
power as the Fama-French three-factor model. In addition to the usual market
risk, our model accounts for a diversification risk, proxied by the
equally-weighted portfolio, and which results from an ``internal consistency
factor'' appearing for arbitrary large economies, as a consequence of the
concentration of the market portfolio when the distribution of the
capitalization of firms is sufficiently heavy-tailed as in real economies. Our
model rationalizes the superior performance of the Fama and French three-factor
model in explaining the cross section of stock returns: the size factor
constitutes an alternative proxy of the diversification factor while the
book-to-market effect is related to the increasing sensitivity of value stocks
to this factor.


title: Rocking and rolling: a can that appears to rock might actually roll

abstract:
  A beer bottle or soda can on a table, when slightly tipped and released,
falls to an upright position and then rocks up to a somewhat opposite tilt.
Superficially this rocking motion involves a collision when the flat circular
base of the container slaps the table before rocking up to the opposite tilt. A
keen eye notices that the after-slap rising tilt is not generally just
diametrically opposite the initial tilt but is veered to one side or the other.
Cushman and Duistermaat (2006) recently noticed such veering when a flat disk
with rolling boundary conditions is dropped nearly flat. Here, we generalize
these rolling disk results to arbitrary axi-symmetric bodies and to
frictionless sliding. More specifically, we study motions that almost but do
not quite involve a face-down collision of the round container's bottom with
the table-top. These motions involve a sudden rapid motion of the contact point
around the circular base. Surprisingly, like for the rolling disk, the net
angle of motion of this contact point is nearly independent of initial
conditions. This angle of turn depends simply on the geometry and mass
distribution but not on the moment of inertia about the symmetry axis. We
derive simple asymptotic formulas for this "angle of turn" of the contact point
and check the result with numerics and with simple experiments. For tall
containers (height much bigger than radius) the angle of turn is just over
$\pi$ and the sudden rolling motion superficially appears as a nearly symmetric
collision leading to leaning on an almost diametrically opposite point on the
bottom rim.


title: Correlation of coming limit price with order book in stock markets

abstract:
  We examine the correlation of the limit price with the order book, when a
limit order comes. We analyzed the Rebuild Order Book of Stock Exchange
Electronic Trading Service, which is the centralized order book market of
London Stock Exchange. As a result, the limit price is broadly distributed
around the best price according to a power-law, and it isn't randomly drawn
from the distribution, but has a strong correlation with the size of cumulative
unexecuted limit orders on the price. It was also found that the limit price,
on the coarse-grained price scale, tends to gather around the price which has a
large size of cumulative unexecuted limit orders.

categories: physics.data-an physics.soc-ph q-fin.ST q-fin.TR


title:
The Golden Gate Textile Barrier: Preserving California Bay of San
  Francisco from a Rising North Pacific Ocean

abstract:
  Climate change in California may require construction of a barrier separating
the Pacific Ocean from San Francisco Bay and the Sacramento River-San Joaquin
River Delta simply because Southern California is remarkably dependent on
freshwater exported from the Delta. We offer a new kind of salt barrier, a
macroproject built of impermeable textile materials stretched across the Golden
Gate beneath the famous bridge. We anticipate it might eventually substitute
for a recently proposed San Francisco In-Stream Tidal Power Plant harnessing a
1.7 m tide at the Bay entrance if future climate conditions Statewide is
conducive. First-glance physics underpin our macroproject.


title: Competition of languages in the presence of a barrier

abstract:
  Using the Schulze model for Monte Carlo simulations of language competition,
we include a barrier between the top half and the bottom half of the lattice.
We check under which conditions two different languages evolve as dominating in
the two halves.


title:
Electron-ion-ion coincidence experiments for photofragmentation of
  polyatomic molecules using pulsed electric fields: treatment of random
  coincidences

abstract:
  In molecular photofragmentation processes by soft X-rays, a number of ionic
fragments can be produced, each having a different abundance and correlation
with the emitted electron kinetic energy. For investigating these fragmentation
processes, electron-ion and electron-ion-ion coincidence experiments, in which
the kinetic energy of electrons are analyzed using an electrostatic analyzer
while the mass of the ions is analyzed using a pulsed electric field, are very
powerful. For such measurements, however, the contribution of random
coincidences is substantial and affects the data in a non-trivial way. Simple
intuitive subtraction methods cannot be applied. In the present paper, we
describe these electron-ion and electron-ion-ion coincidence experiments
together with a subtraction method for the contribution from random
coincidences. We provide a comprehensive set of equations for the data
treatment, including equations for the calculation of error-bars. We
demonstrate the method by applying it to the fragmentation of free CF$_3$SF$_5$
molecules.


title:
Beam-Beam Issues for Colliding Schemes with Large Piwinski Angle and
  Crabbed Waist

abstract:
  Numerical simulations have shown that a recently proposed 'crabbed waist'
scheme of beam-beam collisions can substantially increase the luminosity of a
collider. In this paper we give a qualitative explanation why this scheme
works. For this purpose we use simple geometrical considerations and analyze
peculiar properties of vertical motion modulations by synchrotron and
horizontal betatron oscillations. It is shown that in the 'crabbed waist'
scheme these modulations, which are the main sources of beam-beam resonances
excitation, are significantly suppressed. Some numerical examples demonstrating
the effect of the crabbed waist collisions are also given.


title:
In a book "Tsunami and Nonlinear Waves": Numerical Verification of the
  Hasselmann equation

abstract:
  The purpose of this article is numerical verification of the thory of weak
turbulence. We performed numerical simulation of an ensemble of nonlinearly
interacting free gravity waves (swell) by two different methods: solution of
primordial dynamical equations describing potential flow of the ideal fluid
with a free surface and, solution of the kinetic Hasselmann equation,
describing the wave ensemble in the framework of the theory of weak turbulence.
Comparison of the results demonstrates pretty good applicability of the weak
turbulent approach.


title:
Endogenous and exogenous dynamics in the fluctuations of capital fluxes:
  An empirical analysis of the Chinese stock market

abstract:
  A phenomenological investigation of the endogenous and exogenous dynamics in
the fluctuations of capital fluxes is investigated on the Chinese stock market
using mean-variance analysis, fluctuation analysis and their generalizations to
higher orders. Non-universal dynamics have been found not only in $\alpha$
exponents different from the universal value 1/2 and 1 but also in the
distributions of the ratios $\eta_i = \sigma_i^{\rm{exo}} /
\sigma_i^{\rm{endo}}$. Both the scaling exponent $\alpha$ of fluctuations and
the Hurst exponent $H_i$ increase in logarithmic form with the time scale
$\Delta t$ and the mean traded value per minute $<f_i>$, respectively. We find
that the scaling exponent $\alpha^{\rm{endo}}$ of the endogenous fluctuations
is found to be independent of the time scale, while the exponent of exogenous
fluctuations $\alpha^{\rm{exo}}=1$. Multiscaling and multifractal features are
observed in the data as well. However, the inhomogeneous impact model is not
verified.


title: Visualizing the Doppler Effect

abstract:
  The development of Information and Communication Technologies suggests some
spectacular changes in the methods used for teaching scientific subjects.
Nowadays, the development of software and hardware makes it possible to
simulate processes as close to reality as we want. However, when we are trying
to explain some complex physical processes, it is better to simplify the
problem under study using simplified pictures of the total process by
eliminating some elements that make it difficult to understand this process. In
this work we focus our attention on the Doppler effect which requires the
space-time visualization that is very difficult to obtain using the traditional
teaching resources. We have designed digital simulations as a complement of the
theoretical explanation in order to help students understand this phenomenon.


title: Onset of unsteady horizontal convection in rectangle tank at $Pr=1$

abstract:
  The horizontal convection within a rectangle tank is numerically simulated.
The flow is found to be unsteady at high Rayleigh numbers. There is a Hopf
bifurcation of $Ra$ from steady solutions to periodic solutions, and the
critical Rayleigh number $Ra_c$ is obtained as $Ra_c=5.5377\times 10^8$ for the
middle plume forcing at $Pr=1$, which is much larger than the formerly obtained
value. Besides, the unstable perturbations are always generated from the
central jet, which implies that the onset of instability is due to velocity
shear (shear instability) other than thermally dynamics (thermal instability).
Finally, Paparella and Young's [J. Fluid Mech. 466 (2002) 205] first hypotheses
about the destabilization of the flow is numerically proved, i.e. the middle
plume forcing can lead to a destabilization of the flow.


title:
Suppression of Intensity Fluctuations in Free Space High-Speed Optical
  Communication Based on Spectral Encoding of a Partially Coherent Beam

abstract:
  A new concept of a free-space, high-speed (Gbps) optical communication system
based on spectral encoding of radiation from a broadband pulsed laser is
developed. It is shown that, in combination with the use of partially coherent
laser beams and a relatively slow photosensor, scintillations can be suppressed
by orders of magnitude for distances of more than 10 km. We also consider the
spectral encoding of radiation from a LED as a gigabit rate solution of the
"last mile" problem and rapid-deployment systems for disaster recovery.

categories: physics.optics cond-mat.other physics.ao-ph quant-ph


title: Scattering loss in electro-optic particulate composite materials

abstract:
  The effective permittivity dyadic of a composite material containing
particulate constituent materials with one constituent having the ability to
display the Pockels effect is computed, using an extended version of the
strong-permittivity-fluctuation theory which takes account of both the
distributional statistics of the constituent particles and their sizes.
Scattering loss, thereby incorporated in the effective electromagnetic response
of the homogenized composite material, is significantly affected by the
application of a low-frequency (dc) electric field.


title: Mixing and coherent structures in two-dimensional viscous flows

abstract:
  We introduce a dynamical description based on a probability density
$\phi(\sigma,x,y,t)$ of the vorticity $\sigma$ in two-dimensional viscous flows
such that the average vorticity evolves according to the Navier-Stokes
equations. A time-dependent mixing index is defined and the class of
probability densities that maximizes this index is studied. The time dependence
of the Lagrange multipliers can be chosen in such a way that the masses
$m(\sigma,t):=\intdxdy \phi(\sigma,x,y,t)$ associated with each vorticity value
$\sigma$ are conserved. When the masses $m(\sigma,t)$ are conserved then 1) the
mixing index satisfies an H-theorem and 2) the mixing index is the
time-dependent analogue of the entropy employed in the statistical mechanical
theory of inviscid 2D flows [Miller, Weichman & Cross, Phys. Rev. A \textbf{45}
(1992); Robert & Sommeria, Phys. Rev. Lett. \textbf{69}, 2776 (1992)]. Within
this framework we also show how to reconstruct the probability density of the
quasi-stationary coherent structures from the experimentally determined
vorticity-stream function relations and we provide a connection between this
probability density and an appropriate initial distribution.


title: Tagging heavy flavours with boosted decision trees

abstract:
  This paper evaluates the performance of boosted decision trees for tagging
b-jets. It is shown, using a Monte Carlo simulation of $WH \to l\nu q\bar{q}$
events that boosted decision trees outperform feed-forward neural networks. The
results show that for a b-tagging efficiency of 60% the light jet rejection
given by boosted decision trees is about 35% higher than that given by neural
networks.


title: Surface Conservation Laws at Microscopically Diffuse Interfaces

abstract:
  In studies of interfaces with dynamic chemical composition, bulk and
interfacial quantities coupled via surface conservation laws of excess surface
quantities. While this approach is for microscopically sharp interfaces, its
applicability in the context of microscopically diffuse is less theoretically
well-established. Furthermore, surface conservation laws (and interfacial in
general) are often derived phenomenologically rather than systematically. In
this article, provide a mathematically rigorous justification for surface
conservation laws at diffuse interfaces on an asymptotic analysis of transport
processes in the boundary layer and derive general the surface and normal
fluxes that appear in surface conservation laws. Next, we use
non-thermodynamics to formulate surface conservation laws in terms of chemical
potentials a method for systematically deriving the structure of the
interfacial layer. Finally, we conservation laws for a few examples from
diffusive and electrochemical transport.


title:
Entrainment and stimulated emission of auto-oscillators in an acoustic
  cavity

abstract:
  We report theory, measurements and numerical simulations on nonlinear
piezoelectric ultrasonic devices with stable limit cycles. The devices are
shown to exhibit behavior familiar from the theory of coupled auto-oscillators.
Frequency of auto-oscillation is affected by the presence of an acoustic cavity
as these spontaneously emitting devices adjust their frequency to the spectrum
of the acoustic cavity. Also, the auto-oscillation is shown to be entrained by
an applied field; the oscillator synchronizes to an incident wave at a
frequency close to the natural frequency of the limit cycle. It is further
shown that synchronization occurs here with a phase that can, depending on
details, correspond to stimulated emission: the power emission from the
oscillator is augmented by the incident field. These behaviors are essential to
eventual design of an ultrasonic system that would consist of a number of such
devices entrained to their mutual field, a system that would be an analog to a
laser. A prototype laser is constructed.


title: Collecting single molecules with conventional optical tweezers

abstract:
  The size of particles which can be trapped in optical tweezers ranges from
tens of nanometres to tens of micrometres. This size regime also includes large
single molecules. Here we present experiments demonstrating that optical
tweezers can be used to collect polyethylene oxide (PEO) molecules suspended in
water. The molecules that accumulate in the focal volume do not aggregate and
therefore represent a region of increased molecule concentration, which can be
controlled by the trapping potential. We also present a model which relates the
change in concentration to the trapping potential. Since many protein molecules
have molecular weights for which this method is applicable the effect may be
useful in assisting nucleation of protein crystals.


title: Optical trapping of a cube

abstract:
  The successful development and optimisation of optically-driven micromachines
will be greatly enhanced by the ability to computationally model the optical
forces and torques applied to such devices. In principle, this can be done by
calculating the light-scattering properties of such devices. However, while
fast methods exist for scattering calculations for spheres and axisymmetric
particles, optically-driven micromachines will almost always be more
geometrically complex. Fortunately, such micromachines will typically possess a
high degree of symmetry, typically discrete rotational symmetry. Many current
designs for optically-driven micromachines are also mirror-symmetric about a
plane. We show how such symmetries can be used to reduce the computational time
required by orders of magnitude. Similar improvements are also possible for
other highly-symmetric objects such as crystals. We demonstrate the efficacy of
such methods by modelling the optical trapping of a cube, and show that even
simple shapes can function as optically-driven micromachines.


title: Project-based assessment for graduate coursework in physics

abstract:
  Project-based assessment, in the form of take-home exams, was trialed in an
honours/masters level electromagnetic theory course. This assessment formed an
integral part of the learning experience of the students, and students felt
that this was effective method of learning.


title: Nanotrapping and the thermodynamics of optical tweezers

abstract:
  Particles that can be trapped in optical tweezers range from tens of microns
down to tens of nanometres in size. Interestingly, this size range includes
large macromolecules. We show experimentally, in agreement with theoretical
expectations, that optical tweezers can be used to manipulate single molecules
of polyethylene oxide suspended in water. The trapped molecules accumulate
without aggregating, so this provides optical control of the concentration of
macromolecules in solution. Apart from possible applications such as the
micromanipulation of nanoparticles, nanoassembly, microchemistry, and the study
of biological macromolecules, our results also provide insight into the
thermodynamics of optical tweezers.


title:
Forces from highly focused laser beams: modeling, measurement and
  application to refractive index measurements

abstract:
  The optical forces in optical tweezers can be robustly modeled over a broad
range of parameters using generalsed Lorenz-Mie theory. We describe the
procedure, and show how the combination of experimental measurement of
properties of the trap coupled with computational modeling, can allow unknown
parameters of the particle - in this case, the refractive index - to be
determined.


title:
Guiding, focusing, and sensing on the sub-wavelength scale using
  metallic wire arrays

abstract:
  We show that two-dimensional arrays of thin metallic wires can guide
transverse electromagnetic (TEM) waves and focus them to the spatial dimensions
much smaller that the vacuum wavelength. This guiding property is retained for
the tapered wire bundles which can be used as multi-channel TEM endoscopes:
they capture a detailed electromagnetic field profile created by deeply
sub-wavelength features of the studied sample and magnify it for observation.
The resulting imaging method is superior to the conventional scanning
microscopy because of the parallel nature of the image acquisition by multiple
metal wires. Possible applications include terahertz and mid-infrared endoscopy
with nanoscale resolution.


title: Transformation media that rotate electromagnetic fields

abstract:
  We suggest a way to manipulate electromagnetic wave by introducing a rotation
mapping of coordinates that can be realized by a specific transformation of
permittivity and permeability of a shell surrounding an enclosed domain. Inside
the enclosed domain, the information from outside will appear as if it comes
from a different angle. Numerical simulations were performed to illustrate
these properties.


title: Precise Coulomb wave functions for a wide range of complex l, eta and z

abstract:
  A new algorithm to calculate Coulomb wave functions with all of its arguments
complex is proposed. For that purpose, standard methods such as continued
fractions and power/asymptotic series are combined with direct integrations of
the Schrodinger equation in order to provide very stable calculations, even for
large values of |eta| or |Im(l)|. Moreover, a simple analytic continuation for
Re(z) < 0 is introduced, so that this zone of the complex z-plane does not pose
any problem. This code is particularly well suited for low-energy calculations
and the calculation of resonances with extremely small widths. Numerical
instabilities appear, however, when both |eta| and |Im(l)| are large and
|Re(l)| comparable or smaller than |Im(l)|.


title:
{\it Ab initio} calculations of forbidden transition probabilities and
  lifetimes of low-lying states in V$^{4+}$

abstract:
  Electric quadrupole (E2) and magnetic dipole (M1) transition amplitudes among
the low-lying states of quadruply ionized vanadium V$^{4+}$, important in
various field of experimental and astrophysics are presented very accurately.
Most of these results are reported for the first time in the literature.
Relativistic coupled-cluster theory with single, double and leading triple
excitations has been employed for these calculations. Estimation of different
correlation effects arising through the above formalism have been highlighted
by studying core and valence electrons excitations to the excited states. The
lifetime of the first excited $D$- state is found to be long.


title:
Non-Markov statistical effects of X-ray emission intensity of the
  microquasar GRS 1915+105

abstract:
  In this paper we develop the new approach in time series analysis with a
variable time step and present the results of quantitative and qualitative
estimation of randomness and regularity, and the study of non-Markovian effects
of the X-ray emission intensity of the microquasar GRS 1915+105. Our estimation
is based on the application of the theory of discrete non-Markovian stochastic
processes and gives a wide set of quantitative characteristics and parameters
of the studied system with a variable time step. This set reflects the change
of the effects of randomness and regularity, the alternation of Markovian and
non-Markovian processes in the initial time signals. Initially these
characteristics were determined for the simple model systems constructed by
means of a molecular dynamics method. Further the calculation of these
parameters was executed for the X-ray emission intensity of the microquasar GRS
1915+105. We have developed a theoretical scheme for the detailed analysis of
the time series with a variable time step. The new theory allows us to extract
more detailed information about the X-ray emission of the microquasar GRS
1915+105 from the experimental time series. The received set of the parameters
allows to estimate accurately randomness and stochastic behavior, regularity
and robustness, non-Markovian effects of statistical memory in the intensity of
the X-ray emission. The analysis of the experimental data with a constant and
variable time step is carried out by means of phase portraits, power spectra of
the initial time and event correlation function (TCF and ECF), and memory
functions (MF) of the junior order, the first three points of non-Markovity
parameter.


title: Octonionic Strong and Weak Interactions and Their Quantum Equations

abstract:
  By analogy with the octonionic electromagnetic and gravitational
interactions, the octonionic strong and weak interactions and their quantum
interplays are discussed in the paper. In the weak interaction, the study
deduces some conclusions of field sources and intermediate particles, which are
consistent with the Dirac equation, Yang-Mills equation and some new
intermediate particles etc. In the strong interaction, the research draws some
conclusions of the field sources and intermediate particles, which are
coincident with the Dirac-like equation, three kinds of colors and some new
intermediate particles etc. The researches results show that there exist some
new field source particles in the strong and weak interactions.