title:
Hamilton's principle: why is the integrated difference of kinetic and
  potential energy minimized?

abstract:
  I present an intuitive answer to an often asked question: why is the
integrated difference K-U between the kinetic and potential energy the quantity
to be minimized in Hamilton's principle?
  Using elementary arguments, I map the problem of finding the path of a moving
particle connecting two points to that of finding the minimum potential energy
of a static string. The mapping implies that the configuration of a
non--stretchable string of variable tension corresponds to the spatial path
dictated by the Principle of Least Action; that of a stretchable string in
space-time is the one dictated by Hamilton's principle. This correspondence
provides the answer to the question above: while a downward force curves the
trajectory of a particle in the (x,t) plane downward, an upward force of the
same magnitude stretches the string to the same configuration x(t).


title: Vector Opinion Dynamics in a Bounded Confidence Consensus Model

abstract:
  We study the continuum opinion dynamics of the compromise model of Krause and
Hegselmann for a community of mutually interacting agents, by solving
numerically a rate equation. The opinions are here represented by bidimensional
vectors with real-valued components. We study the situation starting from a
uniform probability distribution for the opinion configuration and for
different shapes of the confidence range. In all cases, we find that the
thresholds for consensus and cluster merging either coincide with their
one-dimensional counterparts, or are very close to them. The symmetry of the
final opinion configuration, when more clusters survive, is determined by the
shape of the opinion space. If the latter is a square, which is the case we
consider, the clusters in general occupy the sites of a square lattice,
although we sometimes observe interesting deviations from this general pattern,
especially near the center of the opinion space.


title: On Friedmann's universes

abstract:
  There is a perfect concordance between Friedmann's cosmological models and
the correspondent (purely gravitational interactions and negligible pressure)
Newtonian models. This renders quite intuitive the fact that in general
relativity no motion of bodies generates gravitational waves.


title:
The motion of a shock wave through a non-uniform one-dimensional medium
  in the case of arbitrary equation of state

abstract:
  The derivation of the equation of one-dimensional movement of a solitary
shock wave is given. This derivation shows, that the differential equation of
movement of a solitary plane shock wave in the channel with variable area, is
exact, if simplifying assumptions, made during derivation, are realized. But
these assumptions in plane geometry it is possible to realize only
approximately; situation with spherical and cylindrical shock waves is
opposite.


title:
An Alkali-Vapor Cell with Metal Coated Windows for Efficient Application
  of an Electric Field

abstract:
  We describe the implementation of a cylindrical T-shaped alkali-vapor cell
for laser spectroscopy in the presence of a longitudinal electric field. The
two windows are used as two electrodes of the high-voltage assembly, which is
made possible by a metallic coating which entirely covers the inner and outer
sides of the windows except for a central area to let the laser beams in and
out of the cell. This allows very efficient application of the electric field,
up to 2 kV/cm in a rather dense superheated vapor, even when significant
photoemission takes place at the windows during pulsed laser irradiation. The
body of the cell is made of sapphire or alumina ceramic to prevent large
currents resulting from surface conduction observed in cesiated glass cells.
The technique used to attach the monocrystalline sapphire windows to the cell
body causes minimal stress birefringence in the windows. In addition,
reflection losses at the windows can be made very small. The vapor cell
operates with no buffer gas and has no magnetic part. The use of this kind of
cell has resulted in an improvement of the signal-to-noise ratio in the
measurement of Parity Violation in cesium vapor underway at ENS, Paris. The
technique can be applied to other situations where a brazed assembly would give
rise to unacceptably large birefringence in the windows.


title: Dynamic positive column in long-gap barrier discharges

abstract:
  A simple analytical model of the barrier discharge in a long gap between
opposing plane electrodes is developed. It is shown that the plasma density
becomes uniform over large part of the gap in the course of the discharge
development, so that one can speak of a formation of a dynamic positive column.
The column completely controls the dynamics of the barrier discharge and
determines such characteristics as the discharge current, discharge duration,
light output, etc. Using the proposed model, all discharge parameters can be
easily evaluated


title:
Back and forth transfer and coherent coupling in a cold Rydberg dipole
  gas

abstract:
  Coupling by the resonant dipole-dipole energy transfer between cold cesium
Rydberg atoms is investigated using time-resolved narrow-band de-excitation
spectroscopy. This technique combines the advantage of efficient Rydberg
excitation with high-resolution spectroscopy at variable interaction times. The
coherent character of the process is studied by back and forth transfer in the
np+np <--> ns+(n+1)s reaction. Decoherence in the ensemble has two different
origins: the atom motion induced by dipole-dipole interaction and the migration
of the s-Rydberg excitation in the environment of p-Rydberg atoms.


title: Influence of Coriolis force on propagation and reflection of long waves

abstract:
  Influence of Coriolis force on propagation and reflection of the stimulated
long waves generated pulsing and harmonic concentrated sources is studied.
Geostrophic stream are found, is received asymptotics for transition mode. It
is established that in case of presence of rectilinear boundary as a result of
reflection Kelvin wave propagating along a boundary is formed.


title:
Scaling collapse and structure functions: Identifying self-affinity in
  finite length time series

abstract:
  Empirical determination of the scaling properties and exponents of time
series presents a formidable challenge in testing, and developing, a
theoretical understanding of turbulence and other out-of-equilibrium phenomena.
We discuss the special case of self affine time series in the context of a
stochastic process. We highlight two complementary approaches to the
differenced variable of the data: i) attempting a scaling collapse of the
Probability Density Functions which should then be well described by the
solution of the corresponding Fokker-Planck equation and ii) using structure
functions to determine the scaling properties of the higher order moments.
Using the example of a L\'{e}vy flight, we demonstrate a method for
conditioning the time series that recovers the underlying self affine scaling
in a finite length time series.


title:
Comparative Graph Theoretical Characterization of Networks of Spam and
  Legitimate Email

abstract:
  Email is an increasingly important and ubiquitous means of communication,
both facilitating contact between private individuals and enabling rises in the
productivity of organizations. However the relentless rise of automatic
unauthorized emails, a.k.a. spam is eroding away much of the attractiveness of
email communication. Most of the attention dedicated to date to spam detection
has focused on the content of the emails or on the addresses or domains
associated with spam senders. Although methods based on these - easily
changeable - identifiers work reasonably well they miss on the fundamental
nature of spam as an opportunistic relationship, very different from the normal
mutual relations between senders and recipients of legitimate email. Here we
present a comprehensive graph theoretical analysis of email traffic that
captures these properties quantitatively. We identify several simple metrics
that serve both to distinguish between spam and legitimate email and to provide
a statistical basis for models of spam traffic.


title: Let Your CyberAlter Ego Share Information and Manage Spam

abstract:
  Almost all of us have multiple cyberspace identities, and these {\em
cyber}alter egos are networked together to form a vast cyberspace social
network. This network is distinct from the world-wide-web (WWW), which is being
queried and mined to the tune of billions of dollars everyday, and until
recently, has gone largely unexplored. Empirically, the cyberspace social
networks have been found to possess many of the same complex features that
characterize its real counterparts, including scale-free degree distributions,
low diameter, and extensive connectivity. We show that these topological
features make the latent networks particularly suitable for explorations and
management via local-only messaging protocols. {\em Cyber}alter egos can
communicate via their direct links (i.e., using only their own address books)
and set up a highly decentralized and scalable message passing network that can
allow large-scale sharing of information and data. As one particular example of
such collaborative systems, we provide a design of a spam filtering system, and
our large-scale simulations show that the system achieves a spam detection rate
close to 100%, while the false positive rate is kept around zero. This system
has several advantages over other recent proposals (i) It uses an already
existing network, created by the same social dynamics that govern our daily
lives, and no dedicated peer-to-peer (P2P) systems or centralized server-based
systems need be constructed; (ii) It utilizes a percolation search algorithm
that makes the query-generated traffic scalable; (iii) The network has a built
in trust system (just as in social networks) that can be used to thwart
malicious attacks; iv) It can be implemented right now as a plugin to popular
email programs, such as MS Outlook, Eudora, and Sendmail.

categories: physics.soc-ph cond-mat.dis-nn cs.CY cs.NI


title:
Watching an uniformly moving source of light using a telescope and a
  frequency-meter

abstract:
  We propose a scenario that involves a stationary observer who detects a point
like source of light moving with constant velocity at a constant altitude,
using a telescope and a frequency-meter. We derive a formula for the angular
velocity at which we should rotate the axis of the telescope and a formula that
relates the proper period at which the source emits successive wave crests and
the proper period at which the stationary observer receives them


title:
Density functional description of water condensation in proximity of
  nanoscale asperity

abstract:
  We apply non-local density functional formalism to describe an equilibrium
distribution of the water-like fluid in the asymmetric nanoscale junction
presenting an atomic force microscope (AFM) tip dwelling above an arbitrary
surface. The hydrogen bonding dominating in intermolecular attraction is
modeled as a square well potential with two adjustable parameters (energy and
length) characterizing well's depth and width. A water meniscus formed inside
nanoscale junction is explicitly described for different humidity. Furthermore,
we suggest a simple approach using polymolecular adsorption isotherms for the
evaluation of an energetic parameter characterizing fluid (water) attraction to
substrate. This model can be easily generalized for more complex geometries and
effective intermolecular potentials. Our study establishes a framework for the
density functional description of fluid with orientational anisotropy induced
by non-uniform external electric field.


title:
The effects of spatial constraints on the evolution of weighted complex
  networks

abstract:
  Motivated by the empirical analysis of the air transportation system, we
define a network model that includes geographical attributes along with
topological and weight (traffic) properties. The introduction of geographical
attributes is made by constraining the network in real space. Interestingly,
the inclusion of geometrical features induces non-trivial correlations between
the weights, the connectivity pattern and the actual spatial distances of
vertices. The model also recovers the emergence of anomalous fluctuations in
the betweenness-degree correlation function as first observed by Guimer\`a and
Amaral [Eur. Phys. J. B {\bf 38}, 381 (2004)]. The presented results suggest
that the interplay between weight dynamics and spatial constraints is a key
ingredient in order to understand the formation of real-world weighted
networks.


title:
Near-field spectroscopy of bimodal size distribution of InAs/AlGaAs
  quantum dots

abstract:
  We report on high-resolution photoluminescence (PL) spectroscopy of spatial
structure of InAs/AlGaAs quantum dots (QDs) by using a near-field scanning
optical microscope (NSOM). The double-peaked distribution of PL spectra is
clearly observed, which is associated with the bimodal size distribution of
single QDs. In particular, the size difference of single QDs, represented by
the doublet spectral distribution, can be directly observed by the NSOM images
of PL.


title:
Tubular geometry construction as a reason for new revision of the
  space-time conception

abstract:
  The tubular geometry (T-geometry) is a generalization of the proper Euclidean
geometry, founded on the property of sigma-immanence. The proper Euclidean
geometry can be described completely in terms of the world function $\sigma
=\rho ^{2}/2$, where $\rho $ is the distance. This property is called the
sigma-immanence. Supposing that any physical geometry is sigma-immanent, one
obtains the T-geometry $\mathcal{G}$, replacing the Euclidean world function
$\sigma_{E}$ by means of $\sigma $ in the sigma-immanent presentation of the
Euclidean geometry. One obtains the T-geometry $\mathcal{G}$, described by the
world function $\sigma $. This method of the geometry construction is very
simple and effective. T-geometry has a new geometric property: nondegeneracy of
geometry. The class of homogeneous isotropic T-geometries is described by a
form of a function of one parameter. Using T-geometry as the space-time
geometry one can construct the deterministic space-time geometries with
primordially stochastic motion of free particles and geometrized particle mass.
Such a space-time geometry defined properly (with quantum constant as an
attribute of geometry) allows one to explain quantum effects as a result of the
statistical description of the stochastic particle motion (without a use of
quantum principles). Geometrization of the particle mass appears to be
connected with the restricted divisibility of the straight line segments. The
statement, that the problem of the elementary particle mass spectrum is rather
a problem of geometry, than that of dynamics, is a corollary of the particle
mass geometrization.


title: Quantum SASE FEL with laser wiggler

abstract:
  In this letter we specify the physical parameters necessary to operate a SASE
FEL in the quantum regime with a laser wiggler. We also show that this is more
feasible in the quantum regime than in the classical one. Specific examples are
given.


title: Strong correlations between text quality and complex networks features

abstract:
  Concepts of complex networks have been used to obtain metrics that were
correlated to text quality established by scores assigned by human judges.
Texts produced by high-school students in Portuguese were represented as
scale-free networks (word adjacency model), from which typical network features
such as the in/outdegree, clustering coefficient and shortest path were
obtained. Another metric was derived from the dynamics of the network growth,
based on the variation of the number of connected components. The scores
assigned by the human judges according to three text quality criteria
(coherence and cohesion, adherence to standard writing conventions and theme
adequacy/development) were correlated with the network measurements. Text
quality for all three criteria was found to decrease with increasing average
values of outdegrees, clustering coefficient and deviation from the dynamics of
network growth. Among the criteria employed, cohesion and coherence showed the
strongest correlation, which probably indicates that the network measurements
are able to capture how the text is developed in terms of the concepts
represented by the nodes in the networks. Though based on a particular set of
texts and specific language, the results presented here point to potential
applications in other instances of text analysis.


title: On the Google-Fame of Scientists and Other Populations

abstract:
  We study the fame distribution of scientists and other social groups as
measured by the number of Google hits garnered by individuals in the
population. Past studies have found that the fame distribution decays either in
power-law [arXiv:cond-mat/0310049] or exponential [Europhys. Lett., 67, (4)
511-516 (2004)] fashion, depending on whether individuals in the social group
in question enjoy true fame or not. In our present study we examine critically
Google counts as well as the methods of data analysis. While the previous
findings are corroborated in our present study, we find that, in most
situations, the data available does not allow for sharp conclusions.


title: The SPHINX spectrometer

abstract:
  The paper describes the SPHINX facility which includes a wide-aperture
magnetic spectrometer with scintillation counters and hodoscopes, proportional
chambers and drift tubes, multichannel electromagnetic and hadron calorimeters,
a guard system, a RICH velocity spectrometer and a hodoscopical threshold
Cherenkov detector for the identification of charged secondary particles. The
SPHINX spectrometer, in its last modification, had the possibility to record
3000-4000 trigger events per an accelerator burst. The spectrometer was used
during the last decade in experiments with the 70GeV proton beam of the IHEP
accelerator U-70.


title: Towards a Universal Theory of Relativity

abstract:
  We discuss here the significance of the generalization of the newtonian
concept of force by that of a transformation of a certain Standard Borel Space
of cardinality $\mathbf{c}$ of the continuum as the ``cause'' behind motions of
material bodies that are representable as Borel measurable subsets of this
space. This generalization forms the basis for a Universal Theory of Relativity
in which, importantly, the fundamental physical constants can only arise from
mutual relationships of the so-defined physical bodies. This Universal
Relativity also has the potential to explain the quantum nature of the physical
world.


title: Momentum Analysis in Strong-field Double Ionization

abstract:
  We provide a basis for the laser intensity dependence of the momentum
distributions of electrons and ions arising from strong-field non-sequential
double ionization (NSDI) at intensities in the range $I=1-6.5 \times 10^{14}
W/cm^2$. To do this we use a completely classical method introduced previously
\cite{ho-etal05}. Our calculated results reproduce the features of experimental
observations at different laser intensities and depend on just two distinct
categories of electon trajectories.


title: Scaling Analysis on Indian Foreign Exchange Market

abstract:
  In this paper we investigate the scaling behavior of the average daily
exchange rate returns of the Indian Rupee against four foreign currencies
namely US Dollar, Euro, Great Britain Pound and Japanese Yen. Average daily
exchange rate return of the Indian Rupee against US Dollar is found to exhibit
a persistent scaling behavior and follow Levy stable distribution. On the
contrary the average daily exchange rate returns of the other three foreign
currencies do not show persistency or antipersistency and follow Gaussian
distribution.


title: Multiple scattering of photons by atomic hyperfine multiplets

abstract:
  Mesoscopic interference effects in multiple scattering of photons depend
crucially on the internal structure of the scatterers. In the present article,
we develop the analytical theory of multiple photon scattering by cold atoms
with arbitrary internal hyperfine multiplets. For a specific application, we
calculate the enhancement factor of elastic coherent backscattering as a
function of detuning from an entire hyperfine multiplet of neighboring
resonances that cannot be considered isolated. Our theory permits to understand
why atoms behave differently from classical Rayleigh point-dipole scatterers,
and how the classical description is recovered for larger but still microscopic
objects like molecules or clusters.


title:
A chiral 4-fermion structure for perturbed atom H: the question of
  antihydrogen

abstract:
  A chiral 4-fermion or 4-unit charge Coulomb structure for perturbed atom H
implies that an intra-atomic H-Hbar transition must obey the same quantitative
criteria as a classical intra-molecular Walden inversion. In a trigonal pyramid
model for chiral molecule ABCD with A at the top, chirality is minimal when A
crosses mirror plane BCD at critical angle pi/2 radians or 90 degrees. This
angle is reproduced with one-electron energies of natural perturbed atom H. We
prove how these results are still consistent with Bohr theory and the observed
H-spectrum. Unlike bound state QED, we promote hydrogen mass to a critical
variable and obtain, from first principles, a critical n-value equal to pi. We
detect a Mexican hat or double well potential, hidden in the observed terms of
natural perturbed atom H, which reveals how the symmetry of the electron-proton
bond is broken naturally. The result is that recent claims by ATHENA- and
ATRAP-collaborations on the mass production of Hbar may well be premature and
that H-Hbar bonding schemes may have to be reconsidered, in line with recent
observations (note added in proof: G. Van Hooydonk, Eur Phys J D, 32, 299
(2005)).


title: Numerical study of the antiferromagnetic Ising model on a hypersphere

abstract:
  We built a model where all spins are in interaction with each other via an
antiferromagnetic Ising Hamiltonian. The geometry of such a model is a
tetrahedron placed on a hypersphere in spaces of dimensions enclosed between 1
and 9. Due to confinement and to the fact that all spins interact which each
other, our spin system exhibit frustration. The temperatures of the observed
antiferro-paramagnetic transitions are equal for all space dimensions to one of
two given values depending on the parity of the space dimension. Moreover, the
order parameter $<m>$, i.e. the magnetization of the system, has been also
studied.


title: Steady States of Epidemic Spreading in Small-World Networks

abstract:
  We consider a standard \textit{susceptible-infected-susceptible} (SIS) model
to study behaviors of steady states of epidemic spreading in small-world
networks. Using analytical methods and large scale simulations, we recover the
usual epidemic behavior with a critical threshold $\lambda_{c}$ below which
infectious diseases die out. Whereas for the spreading rate $\lambda$ far above
$\lambda_{c}$, it was found that the density of infected individuals $\rho$ as
a function of $\lambda$ has the property $\rho \approx F(K)(\ln \lambda - \ln
\lambda_{c})$.


title: On Wave-Particle Duality

abstract:
  By means of a thought-experiment, consisting of an interference experiment
with two interfering beams, it is shown that it can be demonstrated
experimentally that with one single particle a wave can be associated which
propagates in space and time as a physical reality, i.e. that it should not
merely be considered as a distribution of probabilities. The notion "physical
reality" should be understood such that, when this physical reality is
considered in a particular space at a particular time, it should be
experimentally possible to influence this reality in such a way that future
results of experiments show unambiguously that this reality has been causally
influenced by the experimental act in this space and at that time.


title:
Tables of rovibronic term values for singlet electronic states of BH
  molecule

abstract:
  The method for objective (based on Ritz principle only) and optimal
determination of electronic-vibro-rotational (rovibronic) term values from
meassured wavenumbers recently proposed in our previous paper is applied for
singlet electronic states of $^{11}$BH molecule, namely $X^1\Sigma^+$,
$A^1\Pi$, $C'^1\Delta$, $B^1\Sigma^+$, $C^1\Sigma^+$, $D^1\Pi$, $E^1\Sigma^+$,
$F^1\Sigma^+$, $G^1\Pi$, $H^1\Delta$, $I^1\Sigma^+$, $J^1\Sigma^+$. All known
to authors experimental data on the wavenumbers of rovibronic spectral lines
are used. Those are the wavenumber values of 1563 spectral lines of 15 band
systems, obtained in 10 different original papers. As a result 529 term values
with their standard deviations were derived.


title: Change of ownership networks in Japan

abstract:
  As complex networks in economics, we consider Japanese shareholding networks
as they existed in 1985, 1990, 1995, 2000, 2002, and 2003. In this study, we
use as data lists of shareholders for companies listed on the stock market or
on the over-the-counter market. The lengths of the shareholder lists vary with
the companies, and we use lists for the top 20 shareholders. We represent these
shareholding networks as a directed graph by drawing arrows from shareholders
to stock corporations. Consequently, the distribution of incoming edges has an
upper bound, while that of outgoing edges has no bound. This representation
shows that for all years the distributions of outgoing degrees can be well
explained by the power law function with an exponential tail. The exponent
depends on the year and the country, while the power law shape is maintained
universally. We show that the exponent strongly correlates with the long-term
shareholding rate and the cross-shareholding rate.


title: Self-field and magnetic-flux quantum mechanics

abstract:
  Self-field and quantized magnetic-flux are employed to generate the quantum
numbers n, m, and l of atomic physics. Wave-particle duality is shown to be a
natural outcome of having a particle and its self-field.


title: Complexes of DNA Bases and Small Gold Clusters

abstract:
  DNA base-gold interactions are studied theoretically at the DFT level using
Au3 and Au4 clusters as simple catalytic models for Au particles. The bonding
between DNA bases and gold clusters occurs via the anchoring of a Au atom to
the N or O atoms of the bases. In the most stable planar base-Au3 complexes,
the Au-N or Au-O anchor bonds are reinforced by N-H...Au bonds. The mechanism
of formation of these nonconventional H-bonds is discussed.


title:
Droplet motion driven by surface freezing or melting: A mesoscopic
  hydrodynamic approach

abstract:
  A fluid droplet may exhibit self-propelled motion by modifying the wetting
properties of the substrate. We propose a novel model for droplet propagation
upon a terraced landscape of ordered layers formed as a result of surface
freezing driven by the contact angle dependence on the terrace thickness.
Simultaneous melting or freezing of the terrace edge results in a joint
droplet-terrace motion. The model is tested numerically and compared to
experimental observations on long-chain alkane system in the vicinity of the
surface melting point.


title: Numerical simulation of lava flows based on depth-averaged equations

abstract:
  Risks and damages associated with lava flows propagation (for instance the
most recent Etna eruptions) require a quantitative description of this
phenomenon and a reliable forecasting of lava flow paths. Due to the high
complexity of these processes, numerical solution of the complete conservation
equations for real lava flows is often practically impossible. To overcome the
computational difficulties, simplified models are usually adopted, including
1-D models and cellular automata. In this work we propose a simplified 2D model
based on the conservation equations for lava thickness and depth-averaged
velocities and temperature which result in first order partial differential
equations. The proposed approach represents a good compromise between the full
3-D description and the need to decrease the computational time. The method was
satisfactorily applied to reproduce some analytical solutions and to simulate a
real lava flow event occurred during the 1991-93 Etna eruption.


title:
Performance-related differences of bibliometric statistical properties
  of research groups: cumulative advantages and hierarchically layered networks

abstract:
  In this paper we distinguish between top-performance and lower performance
groups in the analysis of statistical properties of bibliometric
characteristics of two large sets of research groups. We find intriguing
differences between top-performance and lower performance groups, but also
between the two sets of research groups. Particularly these latter differences
are interesting, as they may indicate the influence of research management
strategies. Lower performance groups have a larger scale-dependent cumulative
advantage than top-performance groups. We also find that regardless of
performance, larger groups have less not-cited publications. We introduce a
simple model in which processes at the micro level lead to the observed
phenomena at the macro level. Top-performance groups are, on average, more
successful in the entire range of journal impact. We fit our findings into a
concept of hierarchically layered networks. In this concept, the network of
research groups constitutes a layer of one hierarchical step higher than the
basic network of publications connected by citations. The cumulative
size-advantage of citations received by a group looks like preferential
attachment in the basic network in which highly connected nodes (publications)
increase their connectivity faster than less connected nodes. But in our study
it is size that causes an advantage. In general, the larger a group (node in
the research group network), the more incoming links this group acquires in a
non-linear, cumulative way. Moreover, top-performance groups are about an order
of magnitude more efficient in creating linkages (i.e., receiving citations)
than the lower performance groups.


title:
Power-law rheology and mechano-sensing in a cytoskeleton model with
  forced protein unfolding

abstract:
  We describe a model of cytoskeletal mechanics based on the force-induced
conformational change of protein cross-links in a stressed polymer network.
Slow deformation of simulated networks containing cross-links that undergo
repeated, serial domain unfolding leads to an unusual state--with many
cross-links accumulating near the critical force for further unfolding. Thermal
activation of these links gives rise to power-law rheology resembling the
previously unexplained mechanical response of living cells. Moreover, we
hypothesize that such protein cross-links function as biochemical
mechano-sensors of cytoskeletal deformation.


title:
Compensation of nonlinear phase shifts with third-order dispersion:
  fiber stretchers can out-perform grating stretchers in short-pulse fiber
  amplifiers

abstract:
  We show that nonlinear phase shifts and third-order dispersion can compensate
each other in short-pulse fiber amplifiers. In particular, we consider
chirped-pulse fiber amplifiers at wavelengths for which the fiber dispersion is
normal. The nonlinear phase shift accumulated in the amplifier can be
compensated by the third-order dispersion of the combination of a fiber
stretcher and grating compressor. A numerical model is used to predict the
compensation, and initial experimental results that exhibit the main features
of the calculations are presented. In the presence of third-order dispersion,
an optimal nonlinear phase shift reduces the pulse duration, and enhances the
peak power and pulse contrast compared to the pulse produced in linear
propagation. Contrary to common belief, fiber stretchers can perform as well or
better than grating stretchers in fiber amplifiers, while offering the major
practical advantages of a waveguide medium. The relative benefits of a fiber
stretcher increase with increasing pulse energy, so the results presented here
will be relevant to fiber amplifiers designed for the highest pulse energies.


title:
Canonically Transformed Detectors Applied to the Classical Inverse
  Scattering Problem

abstract:
  The concept of measurement in classical scattering is interpreted as an
overlap of a particle packet with some area in phase space that describes the
detector. Considering that usually we record the passage of particles at some
point in space, a common detector is described e.g. for one-dimensional systems
as a narrow strip in phase space. We generalize this concept allowing this
strip to be transformed by some, possibly non-linear, canonical transformation,
introducing thus a canonically transformed detector. We show such detectors to
be useful in the context of the inverse scattering problem in situations where
recently discovered scattering echoes could not be seen without their help.
More relevant applications in quantum systems are suggested.


title:
Morphological Variation in a Toroid Generated from a Single Polymer
  Chain

abstract:
  A single semiflexible polymer chain folds into a toroidal object under poor
solvent conditions. In this study, we examined the morphological change in such
a toroidal state as a function of the width and stiffness of the chain together
with the surface energy, which characterizes the segmental interaction
parameter. Changes in the thickness and outer/inner radius are interpreted in
terms of these parameters. Our theoretical expectation corresponds to the
actual morphological changes in a single giant DNA molecule as observed by
electron microscopy.


title: Of Connections and Fields

abstract:
  We describe some instances of the appearance of Chern's mathematical ideas in
physics. By means of simple examples, we bring out the geometric and
topological ideas which have found application in describing the physical
world. These applications range from magnetic monopoles in electrodynamics to
instantons in quantum chromodynamics to the geometric phase of quantum
mechanics. The first part of this article is elementary and addressed to a
general reader. The second part is somewhat more demanding and is addressed to
advanced students of mathematics and physics.


title: Faraday Instability in a Surface-Frozen Liquid

abstract:
  Faraday surface instability measurements of the critical acceleration, a_c,
and wavenumber, k_c, for standing surface waves on a tetracosanol (C_24H_50)
melt exhibit abrupt changes at T_s=54degC above the bulk freezing temperature.
The measured variations of a_c and k_c vs. temperature and driving frequency
are accounted for quantitatively by a hydrodynamic model, revealing a change
from a free-slip surface flow, generic for a free liquid surface (T>T_s), to a
surface-pinned, no-slip flow, characteristic of a flow near a wetted solid wall
(T < T_s). The change at T_s is traced to the onset of surface freezing, where
the steep velocity gradient in the surface-pinned flow significantly increases
the viscous dissipation near the surface.


title:
Time-Resolved Diffusing Wave Spectroscopy for selected photon paths
  beyond 300 transport mean free paths

abstract:
  This paper is devoted to the theoretical and experimental demonstration of
the possibility to perform time-resolved diffusing wave spectroscopy: we
successfully registered field fluctuations for selected photon path lengths
that can overpass 300 transport mean free paths. Such a performance opens new
possibilities for biomedical optics applications.


title: Budding and Fission of a multiphase vesicle

abstract:
  We present a model of bi-phasic vesicle in the limit of large surface
tension. In this regime, the vesicle is completely stretched and well described
by two spherical caps with a fold which concentrates the membrane stress. The
conservation laws and geometric constraints restrict the space of possible
shapes to a pair of solutions labeled by a parameter $\tau$ given by {\it line
tension/pressure}. For a given $\tau$ value, the two solutions differ by the
length of the interface between domains. For a critical value $\tau\_c$, the
two vesicle shapes become identical and no solution exists above this critical
value. This model sheds new light on two proposed mechanisms (osmotic shocks
and molecule absorption) to explain the budding and the fission in recent
experiments.


title: Improved spectral algorithm for the detection of network communities

abstract:
  We review and improve a recently introduced method for the detection of
communities in complex networks. This method combines spectral properties of
some matrices encoding the network topology, with well known hierarchical
clustering techniques, and the use of the modularity parameter to quantify the
goodness of any possible community subdivision. This provides one of the best
available methods for the detection of community structures in complex systems.


title: FEM Modelling of 3D Photonic Crystals and Photonic Crystal Waveguides

abstract:
  We present a finite-element simulation tool for calculating light fields in
3D nano-optical devices. This allows to solve challenging problems on a
standard personal computer. We present solutions to eigenvalue problems, like
Bloch-type eigenvalues in photonic crystals and photonic crystal waveguides,
and to scattering problems, like the transmission through finite photonic
crystals.
  The discretization is based on unstructured tetrahedral grids with an
adaptive grid refinement controlled and steered by an error-estimator. As
ansatz functions we use higher order, vectorial elements (Nedelec, edge
elements). For a fast convergence of the solution we make use of advanced
multi-grid algorithms adapted for the vectorial Maxwell's equations.


title: The Reversible Phase Transition of DNA-Linked Colloidal Gold Assemblies

abstract:
  We present direct evidence for a reversible phase transition of DNA-linked
colloidal gold assemblies. Transmission electron microscopy and optical
absorption spectroscopy are used to monitor the colloidal gold phase
transition, whose behavior is dominated by DNA interactions. We use
single-stranded DNA-capped colloidal gold that is linked by complementary
linker DNA to form the assemblies. We found that, compared to free DNA, a sharp
melting transition is observed for the DNA-linked colloidal gold assemblies.
The structure of the assemblies is non-crystalline, much like a gel phase,
consistent with theoretical predictions. Optical spectra and melting curves
provide additional evidence of gelation of the colloidal system. The phase
transition and separation are examples of percolation in a dilute solvent.


title:
Relativistic Quantum Dynamics: A non-traditional perspective on space,
  time, particles, fields, and action-at-a-distance

abstract:
  This book is an attempt to build a consistent relativistic quantum theory of
interacting particles. In the first part of the book "Quantum electrodynamics"
we follow rather traditional approach to particle physics. Our discussion
proceeds systematically from the principle of relativity and postulates of
quantum measurements to the renormalization in quantum electrodynamics. In the
second part of the book "Quantum theory of particles" this traditional approach
is reexamined. We find that formulas of special relativity should be modified
to take into account particle interactions. We also suggest reinterpreting
quantum field theory in the language of physical "dressed" particles. This
formulation eliminates the need for renormalization and opens up a new way for
studying dynamical and bound state properties of quantum interacting systems.
The developed theory is applied to realistic physical objects and processes
including the energy spectrum of the hydrogen atom, the decay law of moving
unstable particles, and the electric field of relativistic electron beams.
These results force us to take a fresh look at some core issues of modern
particle theories, in particular, the Minkowski space-time unification, the
role of quantum fields and renormalization as well as the alleged impossibility
of action-at-a-distance. A new perspective on these issues is suggested. It can
help to solve the old problem of theoretical physics -- a consistent
unification of relativity and quantum mechanics.


title: Light-Weight Base Station Antenna with Artificial Wire Medium Lens

abstract:
  In this paper we study the possibility of utilizing a loaded wire medium as
an artificial material for beam shaping element in base station antenna
applications. The wires in the lattice are loaded with a proper capacitive
impedance to come up with a structure effectively operating as a dielectric
lens at the UMTS (Universal Mobile Telecommunications System) frequency range.
It is proven with full-wave simulations that the interpretation of a finite
size wire lattice as a dielectric lens is physically sound even with a moderate
number of lattice periods. A prototype having a mechanically reconfigurable
beam width is constructed and measured. It is shown that very promising
performance can be achieved with a rather simple structure and a cheap
manufacturing process.


title: Microwave Power Standard using Cold Atoms

abstract:
  We discuss how the observation of Rabi flopping oscillations in a laser
cooled atomic sample could be used as a microwave power standard. The rubidium
atoms are first trapped in a standard MOT, then optically pumped, and dropped.
As they enter the interaction region, a resonant pulsed microwave field is
applied. Following the interaction lasting up to 10 ms, a probe laser beam is
turned on and the fluorescence measures the population inversion.


title: Accuracy of an Atomic Microwave Power Standard (Conference digest)

abstract:
  We have studied the accuracy of the atomic microwave power standard. The
atoms are cooled and kept in a Magneto-Optical Trap (MOT), then dropped through
a terminated transmission line (a rectangular, R-70 type, waveguide). The
measurement of the internal atomic state allows an accurate determination of
the transmitted microwave power.


title:
Realization of a Laser Cooled Microwave Power Standard (conference
  digest)

abstract:
  We demonstrate the feasibility of a novel microwave power standard based on
the electromagnetic interaction with cold atoms. Under the effect of the
radiation, the internal state populations will undergo a Rabi oscillation. The
measurement of its frequency will allow the determination of the
electromagnetic field strength.


title: Transfer Entropy Analysis of the Korean Stock Market

abstract:
  This paper has been withdrawn by the authors due to a crucial error in
calculation.


title:
Surface Electromagnetic Waves Thermally Excited: Radiative Heat
  Transfer, Coherence Properties and Casimir Forces Revisited in the Near Field

abstract:
  We review in this article the influence of surface waves on the thermally
excited electromagnetic field. We study in particular the field emitted at
subwalength distances of material surfaces. After reviewing the main properties
of surface waves, we introduce the fluctuation-dissipation theorem that allows
to model the fluctuating electromagnetic fields. We then analyse the
contribution of these waves in a variety of phenomena. They give a leading
contribution to the density of electromagnetic states, they produce both
temporal coherence and spatial coherence in the near field of planar thermal
sources. They can be used to modify radiative properties of surfaces and to
design partially spatially coherent sources. Finally, we discuss the role of
surface waves in the radiative heat transfer and the theory of dispersion
forces at the subwavelength scale.


title: Demonstration of a passive sub-picostrain fiber strain sensor

abstract:
  We demonstrate a fiber Fabry-Perot (FFP) sensor capable of detecting
sub-picostrain signals, from 100 Hz and extending beyond 100 kHz, using the
Pound-Drever-Hall frequency locking technique. A low power diode laser at 1550
nm is locked to a free-space reference cavity to suppress its free-running
frequency noise, thereby stabilizing the laser. The stabilized laser is then
used to interrogate a FFP where the PDH error signal yields the instantaneous
fiber strain.


title:
Exponentially Damped Breit-Pauli Hamiltonian for the Description of
  Positronium Decay and Other High-energy Processes

abstract:
  The conventional explanation for the 1.022 MeV decay of positronium in terms
of the annihilation of an electron and its antiparticle is questioned because
of the impossibility of proving experimentally that matter actually disappears.
Recent work has provided evidence that photons are not destroyed in radiative
absorption, for example, but rather attain an undetectable (E=h(nu)=0) state.
Questioning the creation-annihilation hypothesis in the case of positronium
decay leads to the construction of an exponentially damped Breit-Pauli
Hamiltonian which when employed in a Schroedinger equation gives an e+e- ground
state with a binding energy of 1.022 MeV. The analogous treatment does not
produce any (unobserved) states of similarly low energy for the hydrogen atom,
but by virtue of a simple scaling theorem it does lead to a maximal
proton-antiproton binding energy of 1.876 GeV, which is exactly mp/me times
larger than for e+e-. Arguments are presented to identify the resulting tightly
bound e+ e- system with the photon itself, since both are ascribed a zero rest
mass. The above Hamiltonian is identified with the unified electroweak
interaction, especially since it also proves applicable to the description of
neutrino processes. It is pointed out that the analogous (nu)(bar nu) binary
systems would be subject to predissociation into free neutrinos and
antineutrinos, however, unlike their much more strongly bound e+ e- and p+ p-
counterparts. This observation suggests a different explanation for the
well-known solar neutrino problem than the flavor-oscillation theory which has
been proposed earlier.


title:
The performance analysis dependent on the temperature for EDFAs pumped
  at 1480 nm: A more accurate propagation equation

abstract:
  An analytically expression for the temperature dependence of the signal gain
of an erbium-doped fiber amplifier (EDFA) pumped at 1480 \textit{nm} are
theoretically obtained by solving the propagation equations with the amplified
spontaneous emission (ASE). It is seen that the temperature dependence of the
gain strongly depends on the distribution of population of Er$^{3+}$-ions in
the second level. In addition, the output pump power and the intrinsic
saturation power of the signal beam are obtained as a function of the
temperature. Numerical calculations are carried out for the temperature range
from $-$ 20 to $+$ 60 \textit {$^{o}$C} and the various fiber lengths. But the
other gain parameters, such as the pump and signal wavelengths and their
powers, are taken as constants. It is shown that the gain decreases with
increasing temperature within the range of $L\leq 27 m$.


title:
Monte Carlo transient phonons transport in silicon and germanium at
  nanoscales

abstract:
  Heat transport at nanoscales in semiconductors is investigated with a
statistical method. The Boltzmann Transport Equation (BTE) which characterize
phonons motion and interaction within the crystal lattice has been simulated
with a Monte Carlo technique. Our model takes into account media frequency
properties through the dispersion curves for longitudinal and transverse
acoustic branches. The BTE collisional term involving phonons scattering
processes is simulated with the Relaxation Times Approximation theory. A new
distribution function accounting for the collisional processes has been
developed in order to respect energy conservation during phonons scattering
events. This non deterministic approach provides satisfactory results in what
concerns phonons transport in both ballistic and diffusion regimes. The
simulation code has been tested with silicon and germanium thin films;
temperature propagation within samples is presented and compared to analytical
solutions (in the diffusion regime). The two materials bulk thermal
conductivity is retrieved for temperature ranging between 100 K and 500 K. Heat
transfer within a plane wall with a large thermal gradient (250 K-500 K) is
proposed in order to expose the model ability to simulate conductivity thermal
dependence on heat exchange at nanoscales. Finally, size effects and validity
of heat conduction law are investigated for several slab thicknesses.


title:
JCMmode: An Adaptive Finite Element Solver for the Computation of Leaky
  Modes

abstract:
  We present our simulation tool JCMmode for calculating propagating modes of
an optical waveguide. As ansatz functions we use higher order, vectorial
elements (Nedelec elements, edge elements). Further we construct transparent
boundary conditions to deal with leaky modes even for problems with
inhomogeneous exterior domains as for integrated hollow core Arrow waveguides.
We have implemented an error estimator which steers the adaptive mesh
refinement. This allows the precise computation of singularities near the
metal's corner of a Plasmon-Polariton waveguide even for irregular shaped metal
films on a standard personal computer.


title: $2\delta$-Kicked Quantum Rotors: Localization and `Critical' Statistics

abstract:
  The quantum dynamics of atoms subjected to pairs of closely-spaced
$\delta$-kicks from optical potentials are shown to be quite different from the
well-known paradigm of quantum chaos, the singly-$\delta$-kicked system. We
find the unitary matrix has a new oscillating band structure corresponding to a
cellular structure of phase-space and observe a spectral signature of a
localization-delocalization transition from one cell to several. We find that
the eigenstates have localization lengths which scale with a fractional power
$L \sim \hbar^{-.75}$ and obtain a regime of near-linear spectral variances
which approximate the `critical statistics' relation $\Sigma_2(L) \simeq \chi L
\approx {1/2}(1-\nu) L$, where $\nu \approx 0.75$ is related to the fractal
classical phase-space structure. The origin of the $\nu \approx 0.75$ exponent
is analyzed.

categories: physics.atom-ph cond-mat.other nlin.CD physics.gen-ph


title: Patch antennas with new artificial magnetic layers

abstract:
  A new type of high-impedance surfaces (HIS) has been introduced by C.R.
Simovski et al. recently. In this paper, we propose to use such layers as
artificial magnetic materials in the design of patch antennas. The new HIS is
simulated and patch antennas partially filled by these composite layers are
measured in order to test how much the antenna dimensions can be reduced. In
order to experimentally investigate the frequency behavior of the material,
different sizes of the patches are designed and tested with the same material
layer. Also the height of the patch is changed in order to find the best
possible position for minimizing the antenna size. This composite layer of an
artificial magnetic material has made the antenna smaller while keeping the
bandwidth characteristics of the antenna about the same. About 40% of size
reduction has been achieved.


title:
The day of reckoning: The value of the integration constant in the
  vacuum Schwarzschild solution

abstract:
  The stongest theoretical support for Schwarzschild Black Holes (SBHs) is the
existence of vacuum Schwarzschild/Hilbert solution. The integration constant
alpha_0 in this solution is interpreted as the mass of the BH. But by equating
the 4-volumes (an INVARIANT) associated with the Schwarzschild and the
Eddington-Finkelstein metrics, we directly obtain here the stunning result that
SBHs have the unique mass, M_0 = 0! Thus the Event Horizon of a SBH (R_g = 2M_0
=0) gets merged with the central singularity at R=0 and, after 90 years, the
mysterious EH indeed gets erased from the non-singular R >0 region of a
completely empty (R_0=0) spherical POINT MASS spacetime in accordance with the
intuition of the founders of GR. Consequently the entropy of SBHs have the
unique value of zero, which instantly removes the quantum
mechanical``information paradox'' and the apparent conflict between GR and QM,
the two pillars of modern physics. This direct result firmly establishes the
exciting fact, as far as isolated bodies are concerned, GR is a singularity
free theory even at the classical level! The Black Hole Candidates with mass M
>0 are thus NOT BHs and instead could be HOT compact objects whose possibility
has so far been overlooked in favour of COLD Neutron Stars or BHs. With alpha_0
=0, the BH paradigm collapses instantly because it was built with the
ASSUMPTION alpha_0 >0. This result is dedicated to the occurrence of 100 years
of Relativity.


title: Coupled mode theory for photonic crystal cavity-waveguide interaction

abstract:
  We derive a coupled mode theory for the interaction of an optical cavity with
a waveguide that includes waveguide dispersion. The theory can be applied to
photonic crystal cavity waveguide structures. We derive an analytical solution
to the add and drop spectra arising from such interactions in the limit of
linear dispersion. In this limit, the spectra can accurately predict the cold
cavity quality factor (Q) when the interaction is weak. We numerically solve
the coupled mode equations for the case of a cavity interacting with the band
edge of a periodic waveguide, where linear dispersion is no longer a good
approximation. In this regime, the density of states can distort the add and
drop spectra. This distortion can lead to more than an order of magnitude
overestimation of the cavity Q.


title: Angular momentum of light

abstract:
  By means of the Helmholtz theorem on the decomposition of vector fields, the
angular momentum of the classical electromagnetic field is decomposed, in a
general and manifestly gauge invariant manner, into a spin component and an
orbital component. The method is applied to linearly and circularly polarized
plane waves in their classical and quantum forms.


title:
A high resolution time-of-flight mass spectrometer for the detection of
  ultracold molecules

abstract:
  We have realized a high-resolution time-of-flight mass spectrometer combined
with a magneto-optical trap. The spectrometer enables excellent optical access
to the trapped atomic cloud using specifically devised acceleration and
deflection electrodes. The ions are extracted along a laser beam axis and
deflected onto an off axis detector. The setup is applied to detect atoms and
molecules photoassociated from ultracold atoms. The detection is based on
resonance-enhanced multi-photon ionization. Mass resolution up to m/Delta m_rms
= 1000 at the mass of 133Cs is achieved. The performance of this spectrometer
is demonstrated in the detection of photoassociated ultracold 7Li133Cs
molecules near a large signal of 133Cs ions.


title: An optical clock with neutral atoms confined in a shallow trap

abstract:
  We study the trap depth requirement for the realization of an optical clock
using atoms confined in a lattice. We show that site-to-site tunnelling leads
to a residual sensitivity to the atom dynamics hence requiring large depths (50
to $100 E\_r$ for Sr) to avoid any frequency shift or line broadening of the
atomic transition at the $10^{-17}-10^{-18}$ level. Such large depths and the
corresponding laser power may, however, lead to difficulties (e.g. higher order
light shifts, two-photon ionization, technical difficulties) and therefore one
would like to operate the clock in much shallower traps. To circumvent this
problem we propose the use of an accelerated lattice. Acceleration lifts the
degeneracy between adjacents potential wells which strongly inhibits
tunnelling. We show that using the Earth's gravity, much shallower traps (down
to $5 E\_r$ for Sr) can be used for the same accuracy goal.


title:
Quantification of the differences between quenched and annealed
  averaging for RNA secondary structures

abstract:
  The analytical study of disordered system is usually difficult due to the
necessity to perform a quenched average over the disorder. Thus, one may resort
to the easier annealed ensemble as an approximation to the quenched system. In
the study of RNA secondary structures, we explicitly quantify the deviation of
this approximation from the quenched ensemble by looking at the correlations
between neighboring bases. This quantified deviation then allows us to propose
a constrained annealed ensemble which predicts physical quantities much closer
to the results of the quenched ensemble without becoming technically
intractable.


title:
Angular momentum of the electromagnetic field: the plane wave paradox
  resolved

abstract:
  The angular momentum of a classical electromagnetic plane wave of arbitrary
extent is predicted to be, on theoretical grounds, exactly zero. However,
finite sections of circularly polarized plane waves are found experimentally to
carry angular momentum and it is known that the contribution to the angular
momentum arises from the edges of the beam. A mathematical model is described
that gives a quantitative account of this effect and resolves the paradox.


title:
Flowing Bottomhole Pressure Calculation for a Pumped Well under
  Multiphase Flow

abstract:
  The ability to monitore bottomhole flowing pressure in pumping oil wells
provides important information regarding both reservoir and artificial lift
performance. Converting surface pressure measurements to bottomhole is
currently accomplished by locating the fluid level in the annulus using a sonic
device and then applying a correlation to estimate the density of the gas-cut
liquid column above the perforations. This work proposes a flowing bottomhole
pressure calculation procedure from fluid level measurements. The model is
developed from experimental work and from theoretical arguments. The
calculation procedure developed allows to calculate BHP without shutting the
well, which is common for fluid level casinghead pressure measurements. Also
this method allows to take into account real geometry of the The comparison of
the calculated and measured pump intake pressure shows good accuracy of a
technique. It allows to draw a conclusion for an opportunity to use this method
in practice.


title: Fluctuations in type IV pilus retraction

abstract:
  The type IV pilus retraction motor is found in many important bacterial
pathogens. It is the strongest known linear motor protein and is required for
bacterial infectivity. We characterize the dynamics of type IV pilus retraction
in terms of a stochastic chemical reaction model. We find that a two state
model can describe the experimental force velocity relation and qualitative
dependence of ATP concentration. The results indicate that the dynamics is
limited by an ATP-dependent step at low load and a force-dependent step at high
load, and that at least one step is effectively irreversible in the measured
range of forces. The irreversible nature of the sub-step(s) lead to interesting
predictions for future experiments: We find different parameterizations with
mathematically identical force velocity relations but different fluctuations
(diffusion constant). We also find a longer elementary step compared to an
earlier analysis, which agrees better with known facts about the structure of
the pilus filament and energetic considerations. We conclude that more
experimental data is needed, and that further retraction experiments are likely
to resolve interesting details and give valuable insights into the PilT
machinery. In light of our findings, the fluctuations of the retraction
dynamics emerge as a key property to be studied in future experiments.

categories: physics.bio-ph cond-mat.other q-bio.OT q-bio.SC


title:
Correlation of Beam Electron and LED Signal Losses under Irradiation and
  Long-term Recovery of Lead Tungstate Crystals

abstract:
  Radiation damage in lead tungstate crystals reduces their transparency. The
calibration that relates the amount of light detected in such crystals to
incident energy of photons or electrons is of paramount importance to
maintaining the energy resolution the detection system. We report on tests of
lead tungstate crystals, read out by photomultiplier tubes, exposed to
irradiation by monoenergetic electron or pion beams. The beam electrons
themselves were used to measure the scintillation light output, and a blue
light emitting diode (LED) was used to track variations of crystals
transparency. We report on the correlation of the LED measurement with
radiation damage by the beams and also show that it can accurately monitor the
crystals recovery from such damage.


title: Billiards, Invariant Measures, and Equilibrium Thermodynamics

abstract:
  The questions of justification of the Gibbs canonical distribution for
systems with elastic impacts are discussed. A special attention is paid to the
description of probability measures with densities depending on the system
energy.


title:
Case studies of atomic properties using coupled-cluster and unitary
  coupled-cluster methods

abstract:
  The magnetic dipole and electric quadrupole hyperfine constants of Aluminium
($^{27}Al$) atom are computed using the relativistic coupled cluster (CC) and
unitary coupled cluster (UCC) methods. Effects of electron correlations are
investigated using different levels of CC approximations and truncation
schemes. The ionization potentials, excitation energies, transition
probabilities, oscillator strengths and nuclear quadrupole moment are computed
to assess the accuracy of these schemes. The nuclear quadrupole moment obtained
from the present CC and UCC calculations in the singles and doubles
approximations are 142.5 mbarn and 141.5 mbarn respectively. The discrepancies
between our calculated IPs and EEs and their measured values are better than
0.3%. The other one-electron properties reported here are also in excellent
agreement with the measurements.


title:
Light propagation in finite and infinite photonic crystals: The
  recursive Green's function technique

abstract:
  We report a new computational method based on the recursive Green's function
technique for calculation of light propagation in photonic crystal structures.
The advantage of this method in comparison to the conventional
finite-difference time domain (FDTD) technique is that it computes Green's
function of the photonic structure recursively by adding slice by slice on the
basis of Dyson's equation. This eliminates the need for storage of the wave
function in the whole structure, which obviously strongly relaxes the memory
requirements and enhances the computational speed. The second advantage of this
method is that it can easily account for the infinite extension of the
structure both into the air and into the space occupied by the photonic crystal
by making use of the so-called "surface Green's functions". This eliminates the
spurious solutions (often present in the conventional FDTD methods) related to
e.g. waves reflected from the boundaries defining the computational domain. The
developed method has been applied to study scattering and propagation of the
electromagnetic waves in the photonic band-gap structures including cavities
and waveguides. A particular attention has been paid to surface modes residing
on a termination of a semi-infinite photonic crystal. We demonstrate that
coupling of the surface states with incoming radiation may result in enhanced
intensity of an electromagnetic field on the surface and very high Q factor of
the surface state. This effect can be employed as an operational principle for
surface-mode lasers and sensors.


title: Inside Perspectives on Classical Electromagnetism

abstract:
  The concept "Classical Electromagnetism" in the title of the paper here
refers to a theory built on three foundations: relativity principles, the
original Maxwell's equations, and the mathematics of exterior calculus. In this
theory of electromagnetism the general laws are expressed as geometric
(coordinate-free) relations between quantities on a four-dimensional spacetime
manifold. Based on these laws, and exterior calculus on metric spaces, we
derive fields and relations that describe electromagnetism from the inside
perspective of Lorentz observers, inside the Minkowski spacetime (the ordinary
flat spacetime). It is shown how fields and relations defined on the spacetime
are sliced into three-dimensional fields and relations on time slices, and that
Lorentz observers perceive these as time-dependent fields and relations on a
single three-dimensional Euclidean space. In exterior calculus (on metric
spaces) each field is associated to four field variants from which one can
choose how a field is to appear. Using this feature, we derive alternative
equation systems describing electromagnetism from the inside perspective. In
one system, A, all field quantities are form fields. In another system, C, the
fields are represented as vector and scalar fields. But in contrast to the
traditional Maxwell's equations with div and curl operators, there is here no
need for pseudo-vectors and pseudo-scalars. Some theorems of a pseudo-free
vector analysis, adapted to the C-system, are derived. The paper concludes with
a section where we analyse properties of the electromagnetic field and its laws
with respect to mirror transformations.


title:
The planar-to-tubular structural transition in boron clusters from
  optical absorption

abstract:
  The optical response of the lowest energy isomers of the B_20 family is
calculated using time-dependent density functional theory within a real-space,
real-time scheme. Significant differences are found among the absorption
spectra of the clusters studied. We show that these differences can be easily
related to changes in the overall geometry. Optical spectroscopy is thus an
efficient tool to characterize the planar to tubular structural transition,
known to be present in these boron based systems.


title: Negative Index of Refraction in Optical Metamaterials

abstract:
  An array of pairs of parallel gold nanorods is shown to have a negative
refractive index n'=-0.3 at the optical communication wavelength of 1.5 micron.
This effect results from the plasmon resonance in the pairs of nanorods for
both the electric and magnetic components of light. The refractive index is
retrieved from the direct phase and amplitude measurements for transmission and
reflection, which are all in excellent agreement with our finite difference
time domain simulations. The refraction critically depends on the phase of the
transmitted wave, which emphasizes the importance of phase measurements in
finding n'.


title:
Cosmo-physical effects in structure of the daily and yearly periods of
  change in the shape of the histograms constructed by results of measurements
  of alpha-activity Pu-239

abstract:
  As shown in the previous publications, the shape of the histograms
constructed by measurements of alpha-activity of samples of Pu-239, changes
with periods equal approximately 24 hours, 27 days, and a year. At a higher
resolution each of these periods splits as a minimum in two components: daily
period consists of two: sidereal day (1436 minutes) and solar day (1440
minutes), 27-days period splits in 2 to 3 "sub-periods", and the yearly period
appears to be a join of "calendar" period (which is equal to 1440 x 365 =
525600 minutes) and "solar" period (equal to [(1440 x 365) + 369] =525969
minutes). In the present paper results of more detailed research of this
phenomenon are offered.


title: Hooke's memorandum on the development of orbital dynamics

abstract:
  I discuss a memorandum entitled " A True state of the Case and Controversy
between Sir Isaak Newton and Dr. Robert Hooke as the Priority of that Noble
Hypothesis of motion of ye Planets about ye Sun as their Centers", where Hooke
summarizes his life long contributions to the development of the physics of
orbital motion and the universal theory of gravitation


title: A mathematical theory of citing

abstract:
  Recently we proposed a model in which when a scientist writes a manuscript,
he picks up several random papers, cites them and also copies a fraction of
their references (cond-mat/0305150). The model was stimulated by our discovery
that a majority of scientific citations are copied from the lists of references
used in other papers (cond-mat/0212043). It accounted quantitatively for
several properties of empirically observed distribution of citations. However,
important features, such as power-law distribution of citations to papers
published during the same year and the fact that the average rate of citing
decreases with aging of a paper, were not accounted for by that model. Here we
propose a modified model: when a scientist writes a manuscript, he picks up
several random recent papers, cites them and also copies some of their
references. The difference with the original model is the word recent. We solve
the model using methods of the theory of branching processes, and find that it
can explain the aforementioned features of citation distribution, which our
original model couldn't account for. The model can also explain "sleeping
beauties in science", i.e., papers that are little cited for a decade or so,
and later "awake" and get a lot of citations. Although much can be understood
from purely random models, we find that to obtain a good quantitative agreement
with empirical citation data one must introduce Darwinian fitness parameter for
the papers.


title: Deriving relativistic momentum and energy. II. Three-dimensional case

abstract:
  We generalise a recent derivation of the relativistic expressions for
momentum and kinetic energy from the one-dimensional to the three-dimensional
case.


title: Asymmetric diffusion in the delta-kicked rotor with broken symmetries

abstract:
  We report an experimental investigation of momentum diffusion in the
delta-function kicked rotor where time symmetry is broken by a two-period
kicking cycle and spatial symmetry by an alternating linear potential. The
momentum diffusion constant is thus modified by kick-to-kick correlations which
show a momentum dependence. We exploit this, and a technique involving a moving
optical potential, to create an asymmetry in the momentum diffusion that is due
entirely to the chaotic dynamics.


title:
Commentary on `The Three-Dimensional Current and Surface Wave Equations'
  by George Mellor

abstract:
  The lowest order sigma-transformed momentum equation given by Mellor (J.
Phys. Oceangr. 2003) takes into account a phase-averaged wave forcing based on
Airy wave theory. This equation is shown to be generally inconsistent due to
inadequate approximations of the wave motion. Indeed the evaluation of the
vertical flux of momentum requires an estimation of the pressure $p$ and
coordinate transformation function $s$ to first order in parameters that define
the large scale evolution of the wave field, such as the bottom slope.
Unfortunately there is no analytical expression for $p$ and $s$ at that order.
A numerical correction method is thus proposed and verified. Alternative
coordinate transforms that allow a separation of wave and mean flow momenta do
not suffer from this inconsistency nor require a numerical estimation of the
wave forcing. Indeed, the problematic vertical flux is part of the wave
momentum flux, thus distinct from the mean flow momentum flux, and not directly
relevant to the mean flow evolution.


title: The RFOFO Ionization Cooling Ring for Muons

abstract:
  Practical ionization cooling rings could lead to lower cost or improved
performance in neutrino factory or muon collider designs. The ring modeled here
uses realistic three-dimensional fields. The performance of the ring compares
favorably with the linear cooling channel used in the second US Neutrino
Factory Study. The normalized 6D emittance of an ideal ring is decreased by a
factor of approximately 240, compared with a factor of only 15 for the linear
channel. We also examine such \textit{real-world} effects as windows on the
absorbers and rf cavities and leaving empty lattice cells for injection and
extraction. For realistic conditions the ring decreases the normalized 6D
emittance by a factor of 49.


title:
G7 country Gross Domestic Product (GDP) time correlations. A graph
  network analysis

abstract:
  The correlation between G7 countries has been analysed on the basis of Gross
Domestic Product using different distance functions i.e. discrete, linear
correlation and distribution distance. The distance matrics is analysed by
various graph methods and the percolation threshold is calculated. The
globalization process understood as increas of correlation has been observed.
The applications of different distance function discussed.


title: Time and foreign exchange markets

abstract:
  The definition of time is still an open question when one deals with high
frequency time series. If time is simply the calendar time, prices can be
modeled as continuous random processes and values resulting from transactions
or given quotes are discrete samples of this underlying dynamics. On the
contrary, if one takes the business time point of view, price dynamics is a
discrete random process, and time is simply the ordering according which prices
are quoted in the market. In this paper we suggest that the business time
approach is perhaps a better way of modeling price dynamics than calendar time.
This conclusion comes out from testing probability densities and conditional
variances predicted by the two models against the experimental ones. The data
set we use contains the DEM/USD exchange quotes provided to us by Olsen &
Associates during a period of one year from January to December 1998. In this
period 1,620,843 quotes entries in the EFX system were recorded.


title:
Frequency comparisons and absolute frequency measurements of 171Yb+
  single-ion optical frequency standards

abstract:
  We describe experiments with an optical frequency standard based on a laser
cooled $^{171}$Yb$^+$ ion confined in a radiofrequency Paul trap. The
electric-quadrupole transition from the $^2S_{1/2}(F=0)$ ground state to the
$^2D_{3/2}(F=2)$ state at the wavelength of 436 nm is used as the reference
transition. In order to compare two $^{171}$Yb$^+$ standards, separate
frequency servo systems are employed to stabilize two probe laser frequencies
to the reference transition line centers of two independently stored ions. The
experimental results indicate a relative instability (Allan standard deviation)
of the optical frequency difference between the two systems of $\sigma_y(1000
{\rm s})=5\cdot 10^{-16}$ only, so that shifts in the sub-hertz range can be
resolved. Shifts of several hertz are observed if a stationary electric field
gradient is superimposed on the radiofrequency trap field. The absolute optical
transition frequency of Yb$^+$ at 688 THz was measured with a cesium atomic
clock at two times separated by 2.8 years. A temporal variation of this
frequency can be excluded within a $1\sigma$ relative uncertainty of $4.4\cdot
10^{-15}$ yr$^{-1}$. Combined with recently published values for the constancy
of other transition frequencies this measurement provides a limit on the
present variability of the fine structure constant $\alpha$ at the level of
$2.0\cdot 10^{-15}$ yr$^{-1}$.


title:
Coupling into the slow light mode in slab-type photonic crystal
  waveguides

abstract:
  Coupling of external light signals into a photonic crystal waveguide becomes
increasingly inefficient as the group velocity of the waveguiding mode slows
down. We have systematically studied the efficiency of coupling in the slow
light regime for samples with different truncations of the photonic lattice at
the coupling interface. Inverse power law dependence is found to best fit the
experimental scaling of the coupling loss on the group index. Coupling
efficiency is found to be significantly improved up to group indices of 100 for
a truncation of the lattice that favors the appearance of the photonic surface
states at the coupling interface in resonance with the slow light mode.


title: Calculation of isotope shifts for cesium and francium

abstract:
  We perform ab initio calculations of isotope shifts for isotopes of cesium
(from A=123 to A=137) and francium (from A=207 to A=228). These calculations
start from the relativistic Hartree-Fock method and make use of several
techniques to include correlations. The field (volume) isotope shift is
calculated by means of an all-order correlation potential method and within the
singles-doubles partial triples linearized coupled-cluster approach. Many-body
perturbation theory in two different formulations is used to calculate the
specific mass shift. We discuss the strong points and shortcomings of the
different approaches and implications for parity nonconservation in atoms.
Changes in nuclear charge radii are found by comparing the present calculations
with experiment.


title:
Investigation of fluorescence radiation following radiative
  recombination of ions and electrons

abstract:
  A general expression for the double differential cross section of
fluorescence radiation following photorecombination (PRF) of polarized
electrons and polarized ions is derived by using usual atomic theory methods
and is represented in the form of multiple expansions over spherical tensors.
The ways of the application of the general expression suitable for the specific
experimental conditions are outlined by deriving the asymmetry parameter of
angular distribution of PRF radiation in the case of nonpolarized ions and
electrons. This parameter is calculated for neon-like ions and bare nuclei. A
very strong dependence of the asymmetry parameter of PRF radiation angular
distribution on free electron energy is obtained.


title:
Dependence of shake probability on nuclear charge in Li-, Na- and K-like
  ions

abstract:
  In sudden perturbation approximation, the probability of the shake-up process
accompanying inner-shell ionization is calculated for the isoelectronic
sequences of Li-, Na- and K-like ions in the ground and excited $n$p and $n$d
states. Numerical solutions of Hartree-Fock equations and hydrogen-like radial
orbitals are used. Very large differences between the results of both
approximations for all ions and strong dependences on ion charge are obtained
at the beginning of the isoelectronic sequences.


title: Dirac's Large Number Hypothesis and Quantized Friedman Cosmologies

abstract:
  This paper contains applications of the quantum theory for gravity developed
in the paper " A Sketch for a Quantum Theory of Gravity". Firstly, it is shown
that the theory gives a direct derivation of the implications of Dirac's large
number hypothesis. The three dimensionless large numbers are obtained as three
closed formulae with definite coefficients constructed from known physical
constants. Secondly, the theory is used to derive two quantum Friedman
cosmologies. The first of these Cosmologies is a very simple first
approximation involving a key angular parameter being zero and the second is a
more accurate one involving the same key parameter not being zero. The
cosmological constant plays a basic and fundamental part in the formalism with
very accurate agreement with measurement pertaining.


title: The conceptualization of time and the constancy of the speed of light

abstract:
  In this work we show that the null result of the Michelson-Morley experiment
in vacuum is deeply connected with the notion of time. It can be deduced
without any mathematics only from the assumption that all good clocks can be
used to measure time with the same results, independently of the machinery
involved in their manufacturing.
  A second important assumption, intrinsic to the very notion of time, is that
clocks measure time in the same way in different frames, i.e., the notion of
time is the same in all inertial frames. Under this assumption, we point out
that the "postulate" of constancy of the "two-way" speed of light in vacuum in
all frames independently of the state of motion of the emitting body is also
strongly related to the concept of time, together with the existence of a limit
speed in the "rest frame". This postulate simply results from the construction
of clocks where tic-tacs are made by objects traveling with the limit speed.


title:
Observation of the atmospheric sodium layer with a magneto-optical
  filter (MOF)

abstract:
  The Mesosphere is interested by important chemical and dynamical phenomena,
so observation of its Sodium layer's behavior has became a common target of
several research plans all over the world. In order to study its dynamical and
chemical variation during daytime (so the solar flux, which is not localized,
stimulates the Sodium emission) we want to observe from the space continuously
the Sodium emission (and perform differential analysis looking for periodic
changes), using a small telescope with a Magneto-Optical Filter and a image
sensor.


title: Breached superfluidity of fermionic atoms in magnetic field

abstract:
  We derived the energy gap of a breached pairing superfluidity phase of
fermionic atoms in an external magnetic field in Feshbach resonance experiments
which is determined by the magnetic - field detuning from the Feshbach
resonance. We show that a BCS superfluid state exists only for the magnetic -
field detuning smaller than one critical, and this critical magnetic - field
detuning is determined by the equality of the Zeeman energy splitting for the
magnetic - field detuning to the energy gap $ \Delta_0 $.


title: On the Abuse and Use of Relativistic Mass

abstract:
  The concept of velocity dependent mass, relativistic mass, is examined and is
found to be inconsistent with the geometrical formulation of special
relativity. This is not a novel result; however, many continue to use this
concept and some have even attempted to establish it as the basis for special
relativity. It is argued that the oft-held view that formulations of relativity
with and without relativistic mass are equivalent is incorrect. Left as a
heuristic device a preliminary study of first time learners suggest that
misconceptions can develop when the concept is introduced without basis. In
order to gauge the extent and nature of the use of relativistic mass a survey
of the literature on relativity has been undertaken. The varied and at times
self-contradicting use of this concept points to the lack of clear consensus on
the formulation of relativity. As geometry lies at the heart of all modern
representations of relativity, it is urged, once again, that the use of the
concept at all levels be abandoned.


title: On the Use of Relativistic Mass in Various Published Works

abstract:
  A lengthy bibliography of books referring to special and/or general
relativity is provided to give a background for discussions on the historical
use of the concept of relativistic mass.


title: Slow light in photonic crystals

abstract:
  The problem of slowing down light by orders of magnitude has been extensively
discussed in the literature. Such a possibility can be useful in a variety of
optical and microwave applications. Many qualitatively different approaches
have been explored. Here we discuss how this goal can be achieved in linear
dispersive media, such as photonic crystals. The existence of slowly
propagating electromagnetic waves in photonic crystals is quite obvious and
well known. The main problem, though, has been how to convert the input
radiation into the slow mode without loosing a significant portion of the
incident light energy to absorption, reflection, etc. We show that the
so-called frozen mode regime offers a unique solution to the above problem.
Under the frozen mode regime, the incident light enters the photonic crystal
with little reflection and, subsequently, is completely converted into the
frozen mode with huge amplitude and almost zero group velocity. The linearity
of the above effect allows to slow light regardless of its intensity. An
additional advantage of photonic crystals over other methods of slowing down
light is that photonic crystals can preserve both time and space coherence of
the input electromagnetic wave.


title:
Spatially selective loading of an optical lattice by light-shift
  engineering using an auxiliary laser field

abstract:
  We report on a method of light-shift engineering where an auxiliary laser is
used to tune the atomic transition frequency. The technique is used to
selectively load a specific region of an optical lattice. The results are
explained by calculating the differential light-shift of each hyperfine state.
We conclude that the remarkable spatial selectivity of light-shift engineering
using an auxiliary laser provides a powerful technique to prepare ultra-cold
trapped atoms for experiments on quantum gases and quantum information
processing.


title:
The shadow of light: Lorentz invariance and complementarity principle in
  anomalous photon behaviour

abstract:
  We review the results of two double-slit-like experiments in the infrared
range, which evidence an anomalous behaviour of photon systems under particular
(energy and space) constraints. These outcomes (independently confirmed by
crossing photon beam experiments in both the optical and the microwave range)
apparently rule out the Copenhagen interpretation of the quantum wave, i.e. the
probability wave, by admitting an interpretation in terms of the Einstein-de
Broglie-Bohm hollow wave for photons. Moreover, these experiments support the
interpretation of the hollow wave as a deformation of the Minkowski space-time
geometry. We stress the implications of these experimental results and of their
interpretation for the concept of action-at-a-distance, the Einstein
relativistic correlation and the Bohr principle of complementarity.


title:
General expression for the dielectronic recombination cross section of
  polarized ions with polarized electrons

abstract:
  A general expression for the differential cross section of dielectronic
recombination (DR) of polarized electrons and polarized ions is derived by
using usual atomic theory methods and is represented in the form of multiple
expansions over spherical tensors. The ways of the application of the general
expressions suitable for the specific experimental conditions are outlined by
deriving asymmetry parameters of angular distribution of DR radiation in the
case of nonpolarized and polarized ions and electrons.


title: Hole emitter whispering galleries of photonic quantum ring

abstract:
  We report on the first observation of hole whispering gallery lasers from
semiconductor microcavities with three dimensional optical confinement, with
thresholds potentially reducible to micro-to-nano ampere regimes according to a
quadratic size-dependent reduction, due to ideal quantum wire properties of the
naturally formed photonic quantum rings before imminent recombination in a
dynamic steady state fashion. If the device size grows over a critical
diameter, the quantum ring whispering gallery then begins to disappear.
However, cooperative small hole arrays like 256x256 quantum ring emitters avoid
the criticality and open a possibility of constructing practical dense
electro-pumped micro-to-nano watt emitter arrays, amenable to mega-to-giga ring
emitter chip development via present fabrication techniques.


title: Transport Reversal in a Thermal Ratchet

abstract:
  Transport of a Brownian particle moving in a periodic potential is
investigated in the presence of symmetric unbiased external force. The viscous
medium is alternately in contact with the two heat reservoirs. We present the
analytical expression of the net current at quasi-steady state limit. It is
found that the competition of the asymmetric parameter of potential with the
temperature difference leads to the phenomena like current reversal. The
competition between the two driving factors is a necessary but not a sufficient
condition for current reversals.


title: Heat Flow and Efficiency in a Microscopic Engine

abstract:
  We study the energestics of a thermal motor driven by temperature
differences, which consists of Brownian particles moving in a sawtooth
potential with an external load where the viscous medium is alternately in
contact with hot and cold heat reservoir. The motor can work as a heat engine
or a refrigerator under different conditions. The heat flow via both potential
and kinetic energy are considered. The former is reversible when the engine
works quasistatically and the latter is always irreversible. The efficiency of
the heat engine (Coefficient Of Performance (COP) of a refrigerator) can never
approach Carnot efficiency (COP).


title:
Quadrupole transitions near interface: general theory and application to
  atom inside a planar cavity

abstract:
  Quadrupole radiation of an atom in an arbitrary environment is investigated
within classical as well as quantum electrodynamical approaches. Analytical
expressions for decay rates are obtained in terms of Green function of Maxwell
equations. The equivalence of both approaches is shown. General expressions are
applied to analyze the quadrupole decay rate of an atom placed between two half
spaces with arbitrary dielectric constant. It is shown that in the case when
the atom is close to the surface, the total decay rate is inversely
proportional to the fifth power of distance between an atom and a plane
interface.


title:
PWO crystals for CMS electromagnetic calorimeter : studies of the
  radiation damage kinetics

abstract:
  Kinetics of radiation damage of the PWO crystals under irradiation and
recovery were studied. Crystals were irradiated with dose corresponding to
average one expected in the electromagnetic calorimeter (working dose
irradiation). Radiation damage and recovery were monitored through measurements
of PWO optical transmission. An approach is proposed which allows evaluating
the influence of the PWO crystals properties on the statistical term in the
energy resolution of the electromagnetic calorimeter. The analysis also gives
important information about the nature of the radiation damage mechanism in
scintillation crystals. The method was used during development of technology of
the mass production of radiation hard crystals and during development of
methods for crystals certification


title: How the rich get richer

abstract:
  In our model, $n$ traders interact with each other and with a central bank;
they are taxed on the money they make, some of which is dissipated away by
corruption. A generic feature of our model is that the richest trader always
wins by 'consuming' all the others: another is the existence of a threshold
wealth, below which all traders go bankrupt. The two-trader case is examined in
detail,in the socialist and capitalist limits, which generalise easily to
$n>2$. In its mean-field incarnation, our model exhibits a two-time-scale
glassy dynamics, as well as an astonishing universality.When preference is
given to local interactions in finite neighbourhoods,a novel feature emerges:
instead of at most one overall winner in the system,finite numbers of winners
emerge, each one the overlord of a particular region.The patterns formed by
such winners (metastable states) are very much a consequence of initial
conditions, so that the fate of the marketplace is ruled by its past history;
hysteresis is thus also manifested.


title: Leptokurtic Portfolio Theory

abstract:
  The question of optimal portfolio is addressed. The conventional Markowitz
portfolio optimisation is discussed and the shortcomings due to non-Gaussian
security returns are outlined. A method is proposed to minimise the likelihood
of extreme non-Gaussian drawdowns of the portfolio value. The theory is called
Leptokurtic, because it minimises the effects from "fat tails" of returns. The
leptokurtic portfolio theory provides an optimal portfolio for investors, who
define their risk-aversion as unwillingness to experience sharp drawdowns in
asset prices. Two types of risks in asset returns are defined: a fluctuation
risk, that has Gaussian distribution, and a drawdown risk, that deals with
distribution tails. These risks are quantitatively measured by defining the
"noise kernel" -- an ellipsoidal cloud of points in the space of asset returns.
The size of the ellipse is controlled with the threshold parameter: the larger
the threshold parameter, the larger return are accepted for investors as normal
fluctuations. The return vectors falling into the kernel are used for
calculation of fluctuation risk. Analogously, the data points falling outside
the kernel are used for the calculation of drawdown risks. As a result the
portfolio optimisation problem becomes three-dimensional: in addition to the
return, there are two types of risks involved. Optimal portfolio for
drawdown-averse investors is the portfolio minimising variance outside the
noise kernel. The theory has been tested with MSCI North America, Europe and
Pacific total return stock indices.


title:
Improving antenna near-field pattern by use of artificial impedance
  screens

abstract:
  An antenna prototype utilizing artificial impedance surfaces to control the
near field distribution is described. The antenna is a folded dipole placed
above a finite-size artificial impedance surface. We have found that the field
screening is most effective if the surface is a metal conductor. However, to
achieve a reasonable value of the radiation resistance the dipole should be
located far off the screen. If the surface is a magnetic wall, the antenna
design is more compact, but the field behind the screen is large. Here we
realize a compromise solution using an inductive surface of a moderate surface
impedance, which allows realization of an effective near-field screen with
still a reasonably low-profile design.


title:
Emergence and resilience of social networks: a general theoretical
  framework

abstract:
  We introduce and study a general model of social network formation and
evolution based on the concept of preferential link formation between similar
nodes and increased similarity between connected nodes. The model is studied
numerically and analytically for three definitions of similarity. In common
with real-world social networks, we find coexistence of high and low
connectivity phases and history dependence. We suggest that the positive
feedback between linking and similarity which is responsible for the model's
behaviour is also an important mechanism in real social networks.


title:
On the use of the Kramers-Henneberger Hamiltonian in multi-photon
  ionization calculations

abstract:
  We employ the Kramers-Henneberger Hamiltonian for time-independent
calculations of multi-photon ionization of atoms with one and two electrons. As
compared to the electromagnetic interaction in the length and velocity gauges,
the presently employed Kramers-Henneberger gauge has an advantage of the dipole
matrix elements for the free-free electron transitions being finite and
well-defined quantities. This circumstance simplifies considerably the
computations and allows to obtain accurate results for the two-photon
ionization of realistic atomic systems.


title: Effect of Patterned Slip on Micro and Nanofluidic Flows

abstract:
  We consider the flow of a Newtonian fluid in a nano or microchannel with
walls that have patterned variations in slip length. We formulate a set of
equations to describe the effects on an incompressible Newtonian flow of small
variations in slip, and solve these equations for slow flows. We test these
equations using molecular dynamics simulations of flow between two walls which
have patterned variations in wettability. Good qualitative agreement and a
reasonable degree of quantitative agreement is found between the theory and the
molecular dynamics simulations. The results of both analyses show that
patterned wettability can be used to induce complex variations in flow. Finally
we discuss the implications of our results for the design of microfluidic
mixers using slip.


title: Another thought experiment in special relativity

abstract:
  We present a simple thought experiment in which a beam of light of a finite
length (a light-pulse) enters a detection device that consists of a wave
detector and a light bulb. We examine the experiment from the reference frame
where the device is stationary and from the reference frame where it moves at a
constant velocity along the axis of the beam. We use basic special relativity
to derive the formulas that show how the length of the light beam is
transformed between the reference frames. We further show that the uncommon
formulas for length transformation of a light beam do not contradict the usual
relativistic result that a uniformly moving non-light object will be Lorentz
contracted along the direction of its motion.


title: The rotational temperature of polar molecular ions in Coulomb crystals

abstract:
  With MgH^+ ions as a test case, we investigate to what extent the rotational
motion of smaller polar molecular ions sympathetically cooled into Coulomb
crystals in linear Paul traps couples to the translational motions of the ion
ensemble. By comparing results obtained from rotational state-selective
resonance-enhanced photo-dissociation experiments with data from theoretical
simulations, we conclude that the effective rotational temperature exceeds the
translational temperature (< 100 mK) by more than two orders of magnitude,
indicating a very weak coupling. In fact, the experimental results are
consistent with the rotational temperature being in thermal equilibrium with
the surrounding environment at ~300 K.


title:
Parity nonconservation in electron recombination of multiply charged
  ions

abstract:
  We discuss a parity nonconserving asymmetry in the cross section of KLL
dielectronic recombination of polarized electrons on the hydrogen-like ions
with $Z \lesssim 60$. This effect is strongly enhanced because of the
near-degeneracy of doubly-excited $2l2l'$ states of opposite parity in He-like
ions. For ions with $Z \sim 30$ the asymmetry is of the order of $10^{-9}$. For
$Z \approx 48$ a level crossing takes place, leading to the PNC asymmetry of
$\pm 5\times 10^{-9}$, which is $10^8$ times greater than the basic strength of
the weak interaction in atoms.