title: Multipole-mode surface solitons

abstract:
  We discover multipole-mode solitons supported by the surface between two
distinct periodic lattices imprinted in Kerr-type nonlinear media. Such
solitons are possible because the refractive index modulation at both sides of
the interface glues together their out-of-phase individual constituents.
Remarkably, we find that the new type of solitons may feature highly asymmetric
shapes and yet they are stable over wide domains of their existence, a rare
property to be attributed to their surface nature.


title:
Rainfall Advection using Velocimetry by Multiresolution Viscous
  Alignment

abstract:
  An algorithm to estimate motion from satellite imagery is presented. Dense
displacement fields are computed from time-separated images of of significant
convective activity using a Bayesian formulation of the motion estimation
problem. Ordinarily this motion estimation problem is ill-posed; there are far
too many degrees of freedom than necessary to represent the motion. Therefore,
some form of regularization becomes necessary and by imposing smoothness and
non-divergence as desirable properties of the estimated displacement vector
field, excellent solutions are obtained. Our approach provides a marked
improvement over other methods in conventional use. In contrast to correlation
based approaches, the displacement fields produced by our method are dense,
spatial consistency of the displacement vector field is implicit, and
higher-order and small-scale deformations can be easily handled. In contrast
with optic-flow algorithms, we can produce solutions at large separations of
mesoscale features between large time-steps or where the deformation is rapidly
evolving.

categories: physics.ao-ph physics.comp-ph physics.data-an physics.geo-ph


title:
Sustained Comoving Acceleration of Overdense Plasmas by Colliding Laser
  Pulses

abstract:
  We review recent PIC simulation results which show that double-sided
irradiation of a thin over- dense plasma slab by ultra-intense laser pulses
from both sides can lead to sustained comoving acceleration of surface
electrons to energies much higher than the conventional ponderomotive limit.
The acceleration stops only when the electrons drift transversely out of the
laser beam. We show latest 2.5D results of parameter studies based on finite
laser spot size and discuss future laser experiments that can be used to test
these results.


title: Spectra of Stable Non-Noble Gas Single Bubble Sonoluminescence

abstract:
  A commonly accepted view is that stable Single Bubble Sonoluminescence (SBSL)
can only be achieved in the presence of a noble gas or hydrogen. In air-seeded
bubbles, the content of diatomic gasses is burned off to leave the small amount
of argon needed to sustain stable operation. Here we report that long term
stable SBSL can be sustained with only nitrogen, oxygen, or nitrogen/oxygen
mixtures being present. Compared to that of a stable argon bubble, the emission
is much weaker and the spectrum looks much colder. Oscillating states as well
as recycling states are also observed. An intriguing saturation effect seems
connected with the presence of water vapor in the bubble.


title: Models of wealth distributions: a perspective

abstract:
  A class of conserved models of wealth distributions are studied where wealth
(or money) is assumed to be exchanged between a pair of agents in a population
like the elastically colliding molecules of a gas exchanging energy. All sorts
of distributions from exponential (Boltzmann-Gibbs) to something like Gamma
distributions and to that of Pareto's law (power law) are obtained out of such
models with simple algorithmic exchange processes. Numerical inevstigations,
analysis through transition matrix and a mean field approach are employed to
understand the generative mechanisms. A general scenario is examined wherefrom
a power law and other distributions can emerge.


title:
Light-induced multistability and Freedericksz transition in nematic
  liquid crystals

abstract:
  We study light transmission through a homeotropically oriented nematic liquid
crystal cell and solve self-consistently a nonlinear equation for the nematic
director coupled to Maxwell's equations. We demonstrate that above a certain
threshold of the input light intensity, the liquid-crystal cell changes
abruptly its optical properties due to the light-induced Freedericksz
transition, demonstrating multistable hysteresis-like dependencies in the
transmission. We suggest that these properties can be employed for tunable
all-optical switching photonic devices based on liquid crystals.


title:
Geometrical and Algebraic Approach to Central Molecular Chirality: a
  Chirality Index and an Aufbau Description of Tetrahedral Molecules

abstract:
  On the basis of empirical Fischer projections, we developed an algebraic
approach to central molecular chirality of tetrahedral molecules. The elements
of such an algebra are obtained from the 24 projections which a single chiral
tetrahedron can generate in S and R absolute configurations. They constitute a
matrix representation of the O(4) orthogonal group. According to this
representation, given a molecule with n chiral centres, it is possible to
define an index of chirality, where n is the number of stereogenic centres of
the molecule and p the number of permutations observed under rotations and
superimpositions of the tetrahedral molecule to its mirror image. The chirality
index, not only assigns the global chirality of a given tetrahedral chain, but
indicates also a way to predict the same property for new compounds, which can
be consistently built up


title: Geometrothermodynamics

abstract:
  We present the fundamentals of geometrothermodynamics, an approach to study
the properties of thermodynamic systems in terms of differential geometric
concepts. It is based, on the one hand, upon the well-known contact structure
of the thermodynamic phase space and, on the other hand, on the metric
structure of the space of thermodynamic equilibrium states. In order to make
these two structures compatible we introduce a Legendre invariant set of
metrics in the phase space, and demand that their pullback generates metrics on
the space of equilibrium states. We show that Weinhold's metric, which was
introduced {\it ad hoc}, is not contained within this invariant set. We propose
alternative metrics which allow us to redefine the concept of thermodynamic
length in an invariant manner and to study phase transitions in terms of
curvature singularities.


title:
SASE FEL with energy-chirped electron beam and its application for
  generation of attosecond pulses

abstract:
  Influence of a linear energy chirp in the electron beam on a SASE FEL
operation is studied analytically and numerically using 1-D model. Explicit
expressions for Green's functions and for output power of a SASE FEL are
obtained for high-gain linear regime in the limits of small and large energy
chirp parameter. Saturation length and power versus energy chirp parameter are
calculated numerically. It is shown that the effect of linear energy chirp on
FEL gain is equivalent to the linear undulator tapering (or linear energy
variation along the undulator). A consequence of this fact is a possibility to
perfectly compensate FEL gain degradation, caused by the energy chirp, by means
of the undulator tapering independently of the value of the energy chirp
parameter. An application of this effect for generation of attosecond pulses
from a hard X-ray FEL is proposed. Strong energy modulation within a short
slice of an electron bunch is produced by few-cycle optical laser pulse in a
short undulator, placed in front of the main undulator. Gain degradation within
this slice is compensated by an appropriate undulator taper while the rest of
the bunch suffers from this taper and does not lase. Three-dimensional
simulations predict that short (200 attoseconds) high-power (up to 100 GW)
pulses can be produced in Angstroem wavelength range with a high degree of
contrast. A possibility to reduce pulse duration to sub-100 attosecond scale is
discussed.


title: Type Indeterminacy: A Model for the KT(Kahneman-Tversky)-Man

abstract:
  In this paper we propose to use elements of the mathematical formalism of
Quantum Mechanics to capture the idea that agents' preferences, in addition to
being typically uncertain, can also be indeterminate. They are determined
(i.e., realized, and not merely revealed) only when the action takes place. An
agent is described by a state that is a superposition of potential types (or
preferences or behaviors). This superposed state is projected (or "collapses")
onto one of the possible behaviors at the time of the interaction. In addition
to the main goal of modelling uncertainty of preferences that is not due to
lack of information, this formalism seems to be adequate to describe widely
observed phenomena of noncommutativity in patterns of behavior. We explore some
implications of our approach in a comparison between classical and type
indeterminate rational choice behavior. The potential of the approach is
illustrated in two examples.


title: Precursors of extreme increments

abstract:
  We investigate precursors and predictability of extreme increments in a time
series. The events we are focusing on consist in large increments within
successive time steps. We are especially interested in understanding how the
quality of the predictions depends on the strategy to choose precursors, on the
size of the event and on the correlation strength. We study the prediction of
extreme increments analytically in an AR(1) process, and numerically in wind
speed recordings and long-range correlated ARMA data. We evaluate the success
of predictions via receiver operator characteristics (ROC-curves). Furthermore,
we observe an increase of the quality of predictions with increasing event size
and with decreasing correlation in all examples. Both effects can be understood
by using the likelihood ratio as a summary index for smooth ROC-curves.


title:
Complex dynamics and configurational entropy of spatial optical solitons
  in nonlocal media

abstract:
  Intense light propagating in a nonlinear medium can generate an ensemble of
interacting filaments of light, or spatial solitons. Using nematic liquid
crystals, we demonstrate that they undergo a collective behavior typical of
complex systems, including the formation of clusters and sound-like vibrations,
as well as the reduction of the configurational entropy, controlled by the
degree of nonlocality of the medium.


title:
Resonant electric dipole-dipole interactions between cold Rydberg atoms
  in a magnetic field

abstract:
  Laser cooled Rb atoms were optically excited to 46d Rydberg states. A
microwave pulse transferred a fraction of the atoms to the 47p Rydberg state.
The resonant electric dipole-dipole interactions between atoms in these two
states were probed using the linewidth of the two-photon microwave transition
46d-47d. The presence of a weak magnetic field (approximately 0.5 G) reduced
the observed line broadening, indicating that the interaction is suppressed by
the field. The field removes some of the energy degeneracies responsible for
the resonant interaction, and this is the basis for a quantitative model of the
resulting suppression. A technique for the calibration of magnetic field
strengths using the 34s-34p one-photon transition is also presented.


title:
Derivation of Nonlinear Evolution Equations for Coupled and Single
  Fields in a Quadratic Medium

abstract:
  We derive coupled propagation equations for ultrashort pulses in a degenerate
three-wave mixing process in quadratic media, using approximations consistent
with the slowly evolving wave approximation [T. Brabec and F. Krausz, Phys.
Rev. Lett. 78, 3282 (1997)]. From these we derive an approximate single-field
equation for the fundamental field. This document expands upon mathematics used
for work submitted by the same authors to Physical Review Letters.


title: String Theory - From Physics to Metaphysics

abstract:
  Currently, string theory represents the only advanced approach to a
unification of all interactions, including gravity. In spite of the more than
thirty years of its existence it did not make any empirically testable
predictions. And it is completely unknown which physically interpretable
principles could form the basis of string theory. At the moment, "string
theory" is no theory at all, but rather a labyrinthic structure of mathematical
procedures and intuitions which get their justification from the fact that
they, at least formally, reproduce general relativity and the standard model of
elementary particle physics as low energy approximations. However, there are
now strong indications that string theory does not only reproduce the dynamics
and symmetries of our standard model, but a plethora of different scenarios
with different low energy nomologies and symmetries. String theory seems to
describe not only our world, but an immense landscape of possible worlds. So
far, all attempts to find a selection principle which could be motivated
intratheoretically remained without success. So, recently the idea that the low
energy nomology of our world, and therefore also the observable phenomenology,
could be the result of an anthropic selection from a vast arena of
nomologically different scenarios entered string theory. Although multiverse
scenarios and anthropic selection are not only motivated by string theory, but
lead also to a possible explanation for the fine tuning of the universe, they
are concepts which transcend the framework defined by the epistemological and
methodological rules which conventionally form the basis of physics as an
empirical science.


title:
On the Experimental Estimation of Surface Enhanced Raman Scattering
  (SERS) Cross Sections by Vibrational Pumping

abstract:
  We present an in-depth analysis of the experimental estimation of cross
sections in Surface Enhanced Raman Scattering (SERS) by vibrational pumping.
The paper highlights the advantages and disadvantages of the technique,
pinpoints the main aspects and limitations, and provides the underlying
physical concepts to interpret the experimental results. Examples for several
commonly used SERS probes are given, and a discussion on future possible
developments is also presented.


title: Comment on "Gauge transformations are Canonical transformations"

abstract:
  We comment on the work of Tai L Chow, Eur. J. Phys. 18, 467 (1997). By
considering the Lagrangians which are uniquely defined only to within an
additive total time derivative of a function of co-ordinates and time the
author has tried to show that the gauge transformations which relate these
Lagrangians are canonical transformations. He has obtained the right conclusion
only by using wrong canonical equations and the entire exercise has hence
become erroneous and inconclusive. By using the definition of canonical
transformation through Poisson brackets we prove that the above gauge
transformations are canonical transformations.

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


title:
Redefining Heat and Work in the Right Perspective of
  Second-law-of-Thermodynamics

abstract:
  There are some misnomers and misconceptions about what is heat and what is
work; the recognition of heat and work is even more difficult when it comes to
categorize energy as heat or work. Since both heat and work are energy the
name-confusion does not make much difference from engineering point of view,
but re-defining `heat' and `work' in the right-perspective of
second-law-of-thermodynamics \cite {ref1} is necessary to revise our
understanding at fundamental level. It is concluded that `heat is the energy
carried by mass-less \textit{photons} whereas work is energy carried by
mass-ive material \textit{fermions}'. Revised understanding of heat and work in
this way has far reaching consequences in Physics [2-4]. The present paper lays
emphasis on re-defining heat and work, removing the prevailing misconception,
talks about single photon interaction and heat property of photon. Also,
interestingly, it is noted that different fields of study such as
`Thermodynamics' and `Relativity' are interlinked.


title:
Spectacular Role of Electron Correlation in the Hyperfine Interactions
  in $^2D_{5/2}$ States in Alkaline Earth Ions

abstract:
  The low-lying n(=3,4,5)d $^2D_{5/2}$ states alkaline earth ions are of vital
importance in a number of different physical applications. The hyperfine
structure constants of these states are characterized by unusually strong
electron correlation effects. Relativistic coupled-cluster theory has been
employed to carry out {\it ab initio} calculations of these constants. The role
of the all order core-polarization effects was found to be decisive in
obtaining good agreement of the results of our calculations with accurate
measurements. The present work is an apt demonstration of the power of the
coupled-cluster method to cope with strongly interacting configurations.


title: Vibrational dynamics of confined granular material

abstract:
  By means of two-dimensional contact dynamics simulations, we analyze the
vibrational dynamics of a confined granular layer in response to harmonic
forcing. We use irregular polygonal grains allowing for strong variability of
solid fraction. The system involves a jammed state separating passive (loading)
and active (unloading) states. We show that an approximate expression of the
packing resistance force as a function of the displacement of the free
retaining wall from the jamming position provides a good description of the
dynamics. We study in detail the scaling of displacements and velocities with
loading parameters. In particular, we find that, for a wide range of
frequencies, the data collapse by scaling the displacements with the inverse
square of frequency, the inverse of the force amplitude and the square of
gravity. Interestingly, compaction occurs during the extension of the packing,
followed by decompaction in the contraction phase. We show that the mean
compaction rate increases linearly with frequency up to a characteristic
frequency and then it declines in inverse proportion to frequency. The
characteristic frequency is interpreted in terms of the time required for the
relaxation of the packing through collective grain rearrangements between two
equilibrium states.


title: Chemically driven electron tunnelling pumps

abstract:
  The simplest mechanism for molecular electron pumps is discussed which is
based on nonadiabatic electron tunnelling and nonequilibrium conformational
fluctuations. Such fluctuations can be induced, e.g. by random binding of
negatively charged ATP molecules to the electron-transferring molecular
complex, their subsequent hydrolysis and the products dissociation. The pumping
rate can be controlled by the ATP concentration in solution. Depending on the
model parameters there may exist a critical ATP concentration for the pump to
function. Alternatively, nonequilibrium fluctuations can be induced by
externally applied stochastic electric fields. For realistically chosen
parameters, the mechanism is shown to be robust and highly efficient.


title: Majorana and the investigation of infrared spectra of ammonia

abstract:
  An account is given on the first studies on the physics of ammonia, focusing
on the infrared spectra of that molecule. Relevant contributions from several
authors, in the years until 1932, are pointed out, discussing also an unknown
study by E.Majorana on this topic.


title:
Socioeconophysics: Opinion Dynamics for number of transactions and
  price, a trader based model

abstract:
  Involving effects of media, opinion leader and other agents on the opinion of
individuals of market society, a trader based model is developed and utilized
to simulate price via supply and demand. Pronounced effects are considered with
several weights and some personal differences between traders are taken into
account. Resulting time series and probabilty distribution function involving a
power law for price come out similar to the real ones.


title: Photon-correlation Fourier spectroscopy

abstract:
  We describe a method to probe the spectral fluctuations of a transition over
broad ranges of frequencies and timescales with the high spectral resolution of
Fourier spectroscopy, and a temporal resolution as high as the excited state
lifetime, even in the limit of very low photocounting rates. The method derives
from a simple relation between the fluorescence spectral dynamics of a single
radiating dipole and its fluorescence intensity correlations at the outputs of
a continuously scanning Michelson interferometer. These findings define an
approach to investigate the fast fluorescence spectral dynamics of single
molecules and other faint light sources beyond the time-resolution capabilities
of standard spectroscopy experiments.


title:
An Efficient and Accurate Grid Method for Solving the Time-Dependent
  Schroedinger Equation: Application of Coulomb Wave Function DVR to Atomic
  Systems in Strong Laser Fields

abstract:
  We present an efficient and accurate grid method for solving the
time-dependent Schr\"{o}dinger equation of atomic systems interacting with
intense laser pulses. As usual, the angular part of the wave function is
expanded in terms of spherical harmonics. Instead of the usual finite
difference (FD) scheme, the radial coordinate is discretized using the discrete
variable representation which is constructed from the Coulomb wave function.
For an accurate description of the ionization dynamics of atomic systems, the
Coulomb wave function discrete variable representation (CWDVR) method needs
3-10 times less grid points than the FD method. The resultant grid points of
CWDVR distribute unevenly so that one has finer grid near the origin and
coarser one at larger distances. The other important advantage of the CWDVR
method is that it treats the Coulomb singularity accurately and gives a good
representation of continuum wave functions. The time propagation of the wave
function is implemented using the well-known Arnoldi method. As examples, the
present method is applied to the multiphoton ionization of both H and H$^-$ in
intense laser fields. Short-time excitation and ionization dynamics of H by
static electric fields is also investigated. For a wide range of photon
energies and laser intensities, ionization rates calculated using this method
are in excellent agreement with those from other theoretical calculations.


title:
Report on the Twelfth United Nations/European Space Agency Workshop on
  Basic Space Science

abstract:
  Pursuant to recommendations of the United Nations Conference on the
Exploration and Peaceful Uses of Outer Space (UNISPACE III) and deliberations
of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS),
annual UN/European Space Agency workshops on basic space science have been held
around the world since 1991. These workshops contributed to the development of
astrophysics and space science, particularly in developing nations. Following a
process of prioritization, the workshops identified the following elements as
particularly important for international cooperation in the field: (i)
operation of astronomical telescope facilities implementing TRIPOD, (ii)
virtual observatories, (iii) astrophysical data systems, (iv) concurrent design
capabilities for the development of international space missions, and (v)
theoretical astrophysics such as applications of nonextensive statistical
mechanics. Beginning in 2005, the workshops focus on preparations for the
International Heliophysical Year 2007 (IHY2007). The workshops continue to
facilitate the establishment of astronomical telescope facilities as pursued by
Japan and the development of low-cost, ground-based, world-wide instrument
arrays as lead by the IHY secretariat.


title: Interplay between function and structure in complex networks

abstract:
  We show that abrupt structural transitions can arise in functionally optimal
networks, driven by small changes in the level of transport congestion. Our
results offer an explanation as to why so many diverse species of network
structure arise in Nature (e.g. fungal systems) under essentially the same
environmental conditions. Our findings are based on an exactly solvable model
system which mimics a variety of biological and social networks. We then extend
our analysis by introducing a novel renormalization scheme involving cost
motifs, to describe analytically the average shortest path across
multiple-ring-and-hub networks. As a consequence, we uncover a 'skin effect'
whereby the structure of the inner multi-ring core can cease to play any role
in terms of determining the average shortest path across the network.


title: Many-Body Effects in Hyperfine Interactions in $^{205}$Pb$^+$

abstract:
  Ab initio calculations have been carried out to study the magnetic dipole and
electric quadrupole hyperfine structure constants of $^{205}$Pb$^+$. Many-body
effects have been considered to all orders using the relativistic
coupled-cluster theory in the singles, doubles and partial triples
approximation. The trends of these effects are found to be different from
atomic systems that have been studied earlier.


title:
A Unity of Science, Especially Among Physicists, Is Urgently Needed to
  End Medicine's Lethal Misdirection : Chapter 3. Prevention of the World Avian
  Flu Pandemic

abstract:
  A very inexpensive simple procedure for protection of humans against avian
flu that could blunt a pandemic is described.


title: A Lighthouse Falls

abstract:
  Professor A. K. Raychaudhuri suddenly passed away on 18th June 2005. I have
attempted to give a glimpse of his life and work, and more specifically his
role as a great teacher and inspiring force to three generations of students of
the Presidency College, Kolkata.


title: Epidemic spreading in lattice-embedded scale-free networks

abstract:
  We study geographical effects on the spread of diseases in lattice-embedded
scale-free networks. The geographical structure is represented by the
connecting probability of two nodes that is related to the Euclidean distance
between them in the lattice. By studying the standard Susceptible-Infected
model, we found that the geographical structure has great influences on the
temporal behavior of epidemic outbreaks and the propagation in the underlying
network: the more geographically constrained the network is, the more smoothly
the epidemic spreads.


title:
Enhanced effect of temporal variation of the fine structure constant and
  strong interaction in 229Th

abstract:
  The relative effects of variation of the fine structure constant alpha=e^2/hc
and dimensionless strong interaction parameter m_q/Lambda_{QCD} are enhanced
5-6 orders of magnitude in very narrow ultraviolet transition between the
ground and first excited state in 229Th nucleus (energy (3.5 +/- 1) eV).
Corresponding experiment has potential of improving sensitivity to the
variation of the fundamental constants by 7-10 orders of magnitude (up to
10^{-23} per year).


title:
Spin-dipole induced lifetime of the least-bound quintet sigma state of
  He(2S)+He(2S)

abstract:
  The properties of the least-bound vibrational level (v=14) of the quintet
sigma state formed during the ultracold collision of two spin-polarized
metastable helium atoms are crucial to studies of photoassociation spectroscopy
of metastable helium. We report a calculation of the autoionization lifetime of
this state induced by spin-dipole coupling of the quintet sigma state to the
singlet sigma state from which Penning and associative ionization processes are
highly probable. We find a lifetime of about 150 microseconds, significantly
larger than the recent experimental estimates of (4-5) microseconds.


title: Earth oscillations induced by Hurricane Katrina

abstract:
  Seismograph records show that Katrina was responsible for many motions of the
Earth in addition to the well known microseismic `noise' that is known to
accompany oceanic disturbances.


title:
Efficient kinetic method for fluid simulation beyond the Navier-Stokes
  equation

abstract:
  We present a further theoretical extension to the kinetic theory based
formulation of the lattice Boltzmann method of Shan et al (2006). In addition
to the higher order projection of the equilibrium distribution function and a
sufficiently accurate Gauss-Hermite quadrature in the original formulation, a
new regularization procedure is introduced in this paper. This procedure
ensures a consistent order of accuracy control over the non-equilibrium
contributions in the Galerkin sense. Using this formulation, we construct a
specific lattice Boltzmann model that accurately incorporates up to the third
order hydrodynamic moments. Numerical evidences demonstrate that the extended
model overcomes some major defects existed in the conventionally known lattice
Boltzmann models, so that fluid flows at finite Knudsen number (Kn) can be more
quantitatively simulated. Results from force-driven Poiseuille flow simulations
predict the Knudsen's minimum and the asymptotic behavior of flow flux at large
Kn.


title:
Mathematical model for blood flow autoregulation by endothelium-derived
  relaxing factor

abstract:
  The fluid shear stress is an important regulator of the cardiovascular system
via the endothelium-derived relaxing factor (EDRF) that is Nitric Oxide. This
mechanism involves biochemical reactions in an arterial wall. The
autoregulation process is managed by the vascular tonus and gives the negative
feedback for the shear stress changing. A new mathematical model for the
autoregulation of a blood flow through arteria under the constant transmural
pressure is presented. Endothelium-derived relaxing factor Nitric Oxide, the
multi-layer structure of an arterial wall, and kinetic-diffusion processes are
taken into consideration. The limit case of the thin-wall artery is
analytically studied. The stability condition for a stationary point of the
linearized system is given. The exact stationary solutions of the origin system
are found. The numerical simulation for the autoregulation system is presented.
It is shown the arteria adaptation to an initial radial perturbation and the
transition of the system to new equilibrium state in response on the blood flow
changing.


title: Exploring Complex Networks through Random Walks

abstract:
  Most real complex networks -- such as protein interactions, social contacts,
the internet -- are only partially known and available to us. While the process
of exploring such networks in many cases resembles a random walk, it becomes a
key issue to investigate and characterize how effectively the nodes and edges
of such networks can be covered by different strategies. At the same time, it
is critically important to infer how well can topological measurements such as
the average node degree and average clustering coefficient be estimated during
such network explorations. The present article addresses these problems by
considering random and Barab\'asi-Albert (BA) network models with varying
connectivity explored by three types of random walks: traditional, preferential
to untracked edges, and preferential to unvisited nodes. A series of relevant
results are obtained, including the fact that random and BA models with the
same size and average node degree allow similar node and edge coverage
efficiency, the identification of linear scaling with the size of the network
of the random walk step at which a given percentage of the nodes/edges is
covered, and the critical result that the estimation of the averaged node
degree and clustering coefficient by random walks on BA networks often leads to
heavily biased results. Many are the theoretical and practical implications of
such results.


title:
Concept, realization and characterization of serially powered pixel
  modules (Serial Powering)

abstract:
  We prove and demonstrate here for the example of the large scale pixel
detector of ATLAS that Serial Powering of pixel modules is a viable alternative
and that has been devised and implemented for ATLAS pixel modules using
dedicated on-chip voltage regulators and modified flex hybrids circuits. The
equivalent of a pixel ladder consisting of six serially powered pixel modules
with about 0.3Mpixels has been built and the performance with respect to noise
and threshold stability and operation failures has been studied. We believe
that Serial Powering in general will be necessary for future large scale
tracking detectors.


title: On Felix Klein's Geometric Model of Electromagnetism

abstract:
  In 1917 F. Klein proposed his work on projective geometry to A. Einstein for
further developments of general relativity. Klein had a peculiar way to
consider the relationship between mathematics and physics, based on his
Erlanger Programm and geometrical modeling of physical phenomena. He was aiming
at a physical foundation for non Euclidean geometry. However, the letters he
wrote to Einstein had no sequel.
  We think that F. Klein's ideas still deserve some attention, as they can be
useful for modeling Maxwell's equations with a radically different approach
than resorting to field theories. One reason for looking for alternatives is
that current field theories use geometry exclusively as a formal technique
thereby inhibiting human intuition from grasping the physical world.
  This article collects cues that we deem relevant for a model of
electromagnetic received signals. In the first two chapters we highlight a few
features of classical physics, namely the trajectories of mass points, and the
differences in treating rotations between statics and dynamics. In the third
chapter, we finally review F. Klein's approach toward geometrical modeling of
electromagnetism and special relativity.


title: Why more contact may increase cultural polarization

abstract:
  Following Axelrod's model of cultural dissemination, formal computational
studies of cultural influence have suggested that more contact between
geographically distant regions may increase overall cultural homogeneity and
reduce societal polarization. In the present paper, we show that two plausible
modifications of Axelrod's original mechanism turn the effect of range of
communication upside-down. We assume a continuous rather than a nominal state
space and we add the negative side of social influence, heterophobia and
rejection. Computational analyses of the resulting model demonstrate that now a
larger range of contact can increase rather than decrease the extent of
polarization in the population. Further experiments identify the window of
conditions under which the effect obtains.


title: Tests Of The Charged Particle Stepper With Muons

abstract:
  The muons reconstruction package for the SID/ILC detector has been extended
to include the Electro-Magnetic Calorimeter. The procedure previously used to
reconstruct the charged tracks, an helical fit approximation, has been replaced
by a step by step analytical method accounting for the magnetic field and the
energy loss by ionization. The trajectory of the muons and the impact of the
method on the muon identification efficiency is analyzed. One compares the
behavior of muons of different energies in the (x,y)plane and the (px,py) plane
of the sub-detectors.


title:
Optimization of the Ballistic Guide Design for the SNS FNPB 8.9 A
  Neutron Line

abstract:
  The optimization of the ballistic guide design for the SNS Fundamental
Neutron Physics Beamline 8.9 A line is described. With a careful tuning of the
shape of the curve for the tapered section and the width of the straight
section, this optimization resulted in more than 75% increase in the neutron
flux exiting the 33 m long guide over a straight m=3.5 guide with the same
length.


title: Alignment of the Central D-Zero Detector

abstract:
  The alignment procedure of the Silicon Microstrip Tracker, SMT, and the
Central Fiber Tracker, CFT, is described. Alignment uncertainties and resulting
systematic errors in physics analyses are addressed.


title: Improvements to the LC Muon Tracking and Identification Software

abstract:
  Evolution of the Muon-ID package originally written by R. Markeloff at NIU.
The original method used a helical swimmer to extrapolate the tracks from the
Interaction Point and to collect hits in all sub-detectors: the electromagnetic
and hadronic calorimeters and the muon detector. The package was modified to
replace the swimmer by a stepper which does account both for the effects of the
magnetic field and for the losses by ionization in the material encountered by
the particle. The Modified package shows a substantial improvement in the
efficiency of muon identification. It was applied on bbar-b jets and the muon
detection efficiency and purity was studied. Further improvement should be
reached by accounting for stochastic processes via the utilization of the
Kalman filter.


title:
What sustains cultural diversity and what undermines it? Axelrod and
  beyond

abstract:
  We relax a simplification of Axelrod's (1997) model of cultural dissemination
that has not yet been studied, the assumption that all cultural states are
nominal. We integrate metric states into the original model. Computational
experiments demonstrate that metric states undermine cultural diversity, even
without noise, by creating sufficient overlap between agents for mutual
influence. We then show how adding "bounded confidence" - a recent innovation
in models of social influence - allows cultural diversity to persist. However,
further experiments reveal that the solution is fragile. Diversity can be
sustained only with a relatively small number of metric states, low levels of
noise or narrow confidence intervals.


title: Perturbation Theory for Traveling Droplets

abstract:
  Motion of chemically driven droplets is analyzed by applying a solvability
condition of perturbed hydrodynamic equations affected by the adsorbate
concentration. Conditions for traveling bifurcation analogous to a similar
transition in activator-inhibitor systems are obtained. It is shown that
interaction of droplets leads to either scattering of mobile droplets or
formation of regular patterns, respectively, at low or high adsorbate
diffusivity. The same method is applied to droplets running on growing terrace
edges during surface freezing.


title: Random Walks on Directed Networks: the Case of PageRank

abstract:
  PageRank, the prestige measure for Web pages used by Google, is the
stationary probability of a peculiar random walk on directed graphs, which
interpolates between a pure random walk and a process where all nodes have the
same probability of being visited. We give some exact results on the
distribution of PageRank in the cases in which the damping factor q approaches
the two limit values 0 and 1. When q -> 0 and for several classes of graphs the
distribution is a power law with exponent 2, regardless of the in-degree
distribution. When q -> 1 it can always be derived from the in-degree
distribution of the underlying graph, if the out-degree is the same for all
nodes.


title:
Chaotic Emission from Electromagnetic Systems Considering
  Self-Interaction

abstract:
  The emission of electromagnetic waves from a system described by the
H\'enon-Heiles potential is studied in this work. The main aim being to analyze
the behavior of the system when the damping term is included explicitly into
the equations of motion. Energy losses at the chaotic regime and at the regular
regime are compared. The results obtained here are similar to the case of
gravitational waves emission, as long we consider only the energy loss. The
main difference being that in the present work the energy emitted is explicitly
calculated solving the equation of motion without further approximations. It is
expected that the present analysis may be useful when studying the analogous
problem of dissipation in gravitational systems.

categories: physics.class-ph astro-ph.HE gr-qc nlin.CD


title:
Candidate molecular ions for an electron electric dipole moment
  experiment

abstract:
  This paper is a theoretical work in support of a newly proposed experiment
(R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 2004) that promises
greater sensitivity to measurements of the electron's electric dipole moment
(EDM) based on the trapping of molecular ions. Such an experiment requires the
choice of a suitable molecule that is both experimentally feasible and
possesses an expectation of a reasonable EDM signal. We find that the molecular
ions PtH+, HfH+, and HfF+ are suitable candidates in their low-lying triplet
Delta states. In particular, we anticipate that the effective electric fields
generated inside these molecules are approximately of 73 GV/cm, -17 GV/cm, and
-18 GV/cm respectively. As a byproduct of this discussion, we also explain how
to make estimates of the size of the effective electric field acting in a
molecule, using commercially available, nonrelativistic molecular structure
software.


title: Non-universality of commonly used correlation-energy density functionals

abstract:
  The correlation energies of the helium isoelectronic sequence and of Hooke's
atom isoelectronic sequence have been evaluated using an assortment of local,
gradient and meta-gradient density functionals. The results are compared with
the exact correlation energies, showing that while several of the more recent
density functionals reproduce the exact correlation energies of the helium
isoelectronic sequence rather closely, none is satisfactory for Hooke's atom
isoelectronic sequence. It is argued that the uniformly acceptable results for
the helium sequence can be explained through simple scaling arguments that do
not hold for Hooke's atom sequence, so that the latter system provides a more
sensitive testing ground for approximate density functionals. This state of
affairs calls for further effort towards formulating correlation-energy density
functionals that would be truly universal at least for spherically-symmetric
two-fermion systems.


title: Basic Concepts for a Fundamental Aether Theory

abstract:
  In the light of recent experimental and theoretical data, we go back to the
studies tackled in previous publications [1] and develop some of their
consequences. Some of their main aspects will be studied in further detail. Yet
this text remains self- sufficient. The questions asked following these studies
will be answered. The consistency of these developments in addition to the
experimental results, enable to strongly support the existence of a preferred
aether frame and of the anisotropy of the one-way speed of light in the Earth
frame. The theory demonstrates that the apparent invariance of the speed of
light results from the systematic measurement distortions entailed by length
contraction, clock retardation and the synchronization procedures with light
signals or by slow clock transport. Contrary to what is often believed, these
two methods have been demonstrated to be equivalent by several authors [1]. The
compatibility of the relativity principle with the existence of a preferred
aether frame and with mass-energy conservation is discussed and the relation
existing between the aether and inertial mass is investigated. The experimental
space-time transformations connect co-ordinates altered by the systematic
measurement distortions. Once these distortions are corrected, the hidden
variables they conceal are disclosed. The theory sheds light on several points
of physics which had not found a satisfactory explanation before. (Further
important comments will be made in ref [1d]).


title:
Particles held by springs in a linear shear flow exhibit oscillatory
  motion

abstract:
  The dynamics of small spheres, which are held by linear springs in a low
Reynolds number shear flow at neighboring locations is investigated. The flow
elongates the beads and the interplay of the shear gradient with the nonlinear
behavior of the hydrodynamic interaction among the spheres causes in a large
range of parameters a bifurcation to a surprising oscillatory bead motion. The
parameter ranges, wherein this bifurcation is either super- or subcritical, are
determined.


title:
How the asymmetry of internal potential influences the shape of I-V
  characteristic of nanochannels

abstract:
  Ion transport in biological and synthetic nanochannels is characterized by
such phenomena as ion current fluctuations, rectification, and pumping.
Recently, it has been shown that the nanofabricated synthetic pores could be
considered as analogous to biological channels with respect to their transport
characteristics \cite{Apel, Siwy}. The ion current rectification is analyzed.
Ion transport through cylindrical nanopores is described by the Smoluchowski
equation. The model is considering the symmetric nanopore with asymmetric
charge distribution. In this model, the current rectification in asymmetrically
charged nanochannels shows a diode-like shape of $I-V$ characteristic. It is
shown that this feature may be induced by the coupling between the degree of
asymmetry and the depth of internal electric potential well. The role of
concentration gradient is discussed.


title: 3D Lattice-Boltzmann Model for Magnetic Reconnection

abstract:
  In this paper we develop a 3D Lattice-Boltzmann model that recovers in the
continuous limit the two-fluids theory for plasmas, and consecuently includes
the generalizated Ohm's law. The model reproduces the magnetic reconnection
process just by given the right initial equlibrium conditions in the
magnetotail, without any assumption on the resistivity in the diffusive region.
In this model, the plasma is handled like two fluids with an interaction term,
each one with distribution functions associated to a cubic lattice with 19
velocities (D3Q19). The electromagnetic fields are considered like a third
fluid with an external force on a cubic lattice with 13 velocities (D3Q13). The
model can simulate either viscous fluids in the incompressible limit or
non-viscous compressible fluids, and sucessfully reproduces both the Hartmann
flow and the magnetic reconnection in the magnetotail. The reconnection rate
obtained with this model is R=0.109, which is in excellent agreement with the
observations.


title: Wavelets and Solar Magnetic Activity I: Wavelets on the Edge

abstract:
  The traditional continuous wavelet transform is plagued by the
cone-of-influence, ie wavelets which extend past either end of a finite
timeseries return transform coefficients which tend to decrease as more of the
wavelet is truncated. These coefficients may be corrected simply by rescaling
the remaining wavelet. The corrected wavelet transform displays no
cone-of-influence and maintains reconstruction as either edge is approached. As
an application and example, we present the corrected wavelet transform of the
(derectified) yearly International Sunspot Number, R_i, as a measure of solar
magnetic activity, and compare the yearly solar magnetic power with Oerlemans'
glacial global temperature reconstruction.


title:
The Isotropic to Nematic Liquid Crystalline Phase Transition of F-actin
  Varies from Continuous to First Order

abstract:
  We report that the properties of the isotropic to nematic liquid crystalline
phase transition of F-actin depend critically on the average filament length.
For average filament lengths longer than 2 $\mu$m, we confirm previous findings
that the phase transition is continuous in both alignment and concentration.
For average filament lengths shorter than 2 $\mu$m, we show for the first time
a first order transition with a clear discontinuity in both alignment and
concentration. Tactoidal droplets of coexisting isotropic and nematic phases,
differing in concentration by approximately 30%, form over the course of hours
and appear to settle into near equilibrium metastable states.


title: Detecting level crossings without looking at the spectrum

abstract:
  In many physical systems it is important to be aware of the crossings and
avoided crossings which occur when eigenvalues of a physical observable are
varied using an external parameter. We have discovered a powerful algebraic
method of finding such crossings via a mapping to the problem of locating the
roots of a polynomial in that parameter. We demonstrate our method on atoms and
molecules in a magnetic field, where it has implications in the search for
Feshbach resonances. In the atomic case our method allows us to point out a new
class of invariants of the Breit-Rabi Hamiltonian of magnetic resonance. In the
case of molecules, it enables us to find curve crossings with practically no
knowledge of the corresponding Born-Oppenheimer potentials.


title: Excitation of surface dipole and solenoidal modes on toroidal structures

abstract:
  The time dependent Schrodinger equation inclusive of curvature effects is
developed for a spinless electron constrained to motion on a toroidal surface
and subjected to circularly polarized and linearly polarized waves in the
microwave regime. A basis set expansion is used to determine the character of
the surface currents as the system is driven at a particular resonance
frequency. Surface current densities and magnetic moments corresponding to
those currents are calculated. It is shown that the currents can yield magnetic
moments large not only along the toroidal symmetry axis, but along directions
tangential and normal to the toroidal surface as well.


title: Network analysis of online bidding activity

abstract:
  With the advent of digital media, people are increasingly resorting to online
channels for commercial transactions. Online auction is a prototypical example.
In such online transactions, the pattern of bidding activity is more complex
than traditional online transactions; this is because the number of bidders
participating in a given transaction is not bounded and the bidders can also
easily respond to the bidding instantaneously. By using the recently developed
network theory, we study the interaction patterns between bidders (items) who
(that) are connected when they bid for the same item (if the item is bid by the
same bidder). The resulting network is analyzed by using the hierarchical
clustering algorithm, which is used for clustering analysis for expression data
from DNA microarrays. A dendrogram is constructed for the item subcategories;
this dendrogram is compared with a traditional classification scheme. The
implication of the difference between the two is discussed.


title:
An extension of the Hirsch Index: Indexing scientific topics and
  compounds

abstract:
  An interesting twist of the Hirsch index is given, in terms of an index for
topics and compounds. By comparing both the hb index and m for a number of
compounds and topics, it can be used to differentiate between a new so-called
hot topic with older topics. This quick method is shown to help new comers to
identify how much interest and work has already been achieved in their chosen
area of research.


title: Investigating Auto-correlation of Scattered Light of Mixed Particles

abstract:
  In this work, the normalized time auto-correlation function of the electric
field of the light $g^{(1)}(\tau)$ that is scattered by the two kinds of
particles in dispersion is investigated. The results show that the logarithm of
$g^{(1)}(\tau)$ can be consistent with a line and many reasons can cause the
deviations between an exponentiality and plots of $g^{(1)}(\tau)$ as a function
of delay time $\tau$. The nonexponentiality of $g^{(1)}(\tau)$ is not only
determined by the particle size distribution and scattering angle but also
greatly influenced by the relationship between the concentrations, mass
densities and the values that the refractive index of the material expands as a
function of the concentration of the two kinds of particles.


title:
Enhancing the photomixing efficiency of optoelectronic devices in the
  terahertz regime

abstract:
  A method to reduce the transit time of majority of carriers in photomixers
and photo detectors to $< 1$ ps is proposed. Enhanced optical fields associated
with surface plasmon polaritons, coupled with velocity overshoot phenomenon
results in net decrease of transit time of carriers. As an example, model
calculations demonstrating $> 280\times$ (or $\sim$2800 and 31.8 $\mu$W at 1
and 5 THz respectively) improvement in THz power generation efficiency of a
photomixer based on Low Temperature grown GaAs are presented. Due to minimal
dependence on the carrier recombination time, it is anticipated that the
proposed method paves the way for enhancing the speed and efficiency of
photomixers and detectors covering UV to far infrared communications
wavelengths (300 to 1600 nm).


title:
Convergence and round-off errors in a two-dimensional eigenvalue problem
  using spectral methods and Arnoldi-Chebyshev algorithm

abstract:
  An efficient way of solving 2D stability problems in fluid mechanics is to
use, after discretization of the equations that cast the problem in the form of
a generalized eigenvalue problem, the incomplete Arnoldi-Chebyshev method. This
method preserves the banded structure sparsity of matrices of the algebraic
eigenvalue problem and thus decreases memory use and CPU-time consumption.
  The errors that affect computed eigenvalues and eigenvectors are due to the
truncation in the discretization and to finite precision in the computation of
the discretized problem. In this paper we analyze those two errors and the
interplay between them. We use as a test case the two-dimensional eigenvalue
problem yielded by the computation of inertial modes in a spherical shell. This
problem contains many difficulties that make it a very good test case. It turns
out that that single modes (especially most-damped modes i.e. with high spatial
frequency) can be very sensitive to round-off errors, even when apparently good
spectral convergence is achieved. The influence of round-off errors is analyzed
using the spectral portrait technique and by comparison of double precision and
extended precision computations. Through the analysis we give practical recipes
to control the truncation and round-off errors on eigenvalues and eigenvectors.


title: Analysis of the atom-number correlation function in a few-atom trap

abstract:
  Stochastic properties of loading and loss mechanism in a few atom trap are
analyzed. An approximate formula is derived for the atom-number correlation
function for the trapped atoms in the limit of reasonably small two-atom loss
rate. Validity of the approximate formula is confirmed by numerical
simulations.


title: Heat transfer in theory of relativity

abstract:
  The traditional Fourier equation just allows us to study the evolution of
temperature in an "undeformable" bar. The search for its relativistic variant
is a task which is expected to fail because in relativity there are no
undeformable bars. Rigid bodies, in the sense of "as rigid as possible", are
deformables. In this work we show how to write in relativity the system of
equations necessary to study simultaneously deformation and temperature
evolution along a rigid deformable bar. The solutions of the two simultaneous
equations is discussed assuming convenient constitutive relations for the
material. An application is presented.


title:
Characterisation of carbon dust produced in sputtering discharges and in
  the Tore Supra tokamak

abstract:
  The sputtering of inside wall components of tokamaks can lead to the
injection of supersaturated vapour in the plasma edge. The resulting
condensation favours the formation of clusters which can give rise to solid
particulates by further accretion. Sputtering discharges are proposed to have
highlight on the formation of carbonaceous dust observed in the tokamaks with
graphite based wall components. The flux of the sputtered carbon atoms is
evaluated in the conditions of our laboratory discharges as well as the
evolution of their energy distribution. It is shown that a cooling mechanism
occurs through collisions with the discharge argon atoms, leading to a
nucleation phase. A comparison between the carbon structure of the resulting
dust particles and a dust sample collected in the Tore Supra tokamak is
proposed. The structural differences are discussed and can be correlated to
specific plasma conditions.


title: New parametrization for differences between plasma kinetic codes

abstract:
  Validation and verification of plasma kinetics codes requires the development
of quantitative methods and techniques for code comparisons. We describe two
parameters that can be used for characterization of differences between such
codes. It is shown that these parameters, which are determined from the most
general results of kinetic codes, can provide important information on the
differences between the basic rate coefficients employed. Application of this
method is illustrated by comparisons of some results from the 3rd NLTE Code
Comparison Workshop for carbon, germanium, and gold plasmas.


title: When hot water freezes before cold

abstract:
  I suggest that the origin of the Mpemba effect (the freezing of hot water
before cold) is freezing-point depression by solutes, either gaseous or solid,
whose solubility decreases with increasing temperature so that they are removed
when water is heated. They are concentrated ahead of the freezing front by zone
refining in water that has not been heated, reduce the temperature of the
freezing front, and thereby reduce the temperature gradient and heat flux,
slowing the progress of the front. I present a simple calculation of this
effect, and suggest experiments to test this hypothesis.

categories: physics.chem-ph cond-mat.stat-mech physics.gen-ph physics.pop-ph


title: On Superstring and Supergravity Dimensions

abstract: This paper has been withdrawn by the author.


title: Dynamics of Multi-Player Games

abstract:
  We analyze the dynamics of competitions with a large number of players. In
our model, n players compete against each other and the winner is decided based
on the standings: in each competition, the mth ranked player wins. We solve for
the long time limit of the distribution of the number of wins for all n and m
and find three different scenarios. When the best player wins, the standings
are most competitive as there is one-tier with a clear differentiation between
strong and weak players. When an intermediate player wins, the standings are
two-tier with equally-strong players in the top tier and clearly-separated
players in the lower tier. When the worst player wins, the standings are least
competitive as there is one tier in which all of the players are equal. This
behavior is understood via scaling analysis of the nonlinear evolution
equations.


title: Generation of Traveling Surface Plasmon Waves by Free-Electron Impact

abstract:
  The injection of a beam of free 50 keV electrons into an unstructured gold
surface creates a highly localized source of traveling surface plasmons with
spectrum centered around 1.8 eV. The plasmons were detected by a controlled
decoupling into light with a grating at a distance from the excitation point.
The dominant contribution to the plasmon generation appears to come from the
recombination of d-band holes created by the electron beam excitation.


title:
Theory of high harmonic generation in relativistic laser interaction
  with overdense plasma

abstract:
  High harmonic generation due to the interaction of a short ultra relativistic
laser pulse with overdense plasma is studied analytically and numerically. On
the basis of the ultra relativistic similarity theory we show that the high
harmonic spectrum is universal, i.e. it does not depend on the interaction
details. The spectrum includes the power law part $I_n\propto n^{-8/3}$ for
$n<\sqrt{8\alpha}\gamma_{\max}^3$, followed by exponential decay. Here
$\gamma_{\max}$ is the largest relativistic $\gamma$-factor of the plasma
surface and $\alpha$ is the second derivative of the surface velocity at this
moment. The high harmonic cutoff at $\propto \gamma_{\max}^3$ is parametrically
larger than the $4 \gamma_{\max}^2$ predicted by the ``oscillating mirror''
model based on the Doppler effect. The cornerstone of our theory is the new
physical phenomenon: spikes in the relativistic $\gamma$-factor of the plasma
surface. These spikes define the high harmonic spectrum and lead to attosecond
pulses in the reflected radiation.


title: Rayleigh-Sommerfeld Fraunhofer Diffraction

abstract:
  Treatments of Fraunhofer diffraction normally approximate the inclination
factor in the diffraction integral by 1, but this is not necessary. In this
paper, the Rayleigh-Sommerfeld diffraction integral is used and a complete
description of Fraunhofer diffraction is given, with the minimum possible
number of approximations made. A focused wave is examined before, at, and after
its focal point to elucidate the exact role of the Fourier transform in
describing Fraunhofer diffraction and to derive the Guoy phase shift.


title: On the origin dependence of multipole moments in electromagnetism

abstract:
  The standard description of material media in electromagnetism is based on
multipoles. It is well known that these moments depend on the point of
reference chosen, except for the lowest order. It is shown that this "origin
dependence" is not unphysical as has been claimed in the literature but forms
only part of the effect of moving the point of reference. When also the
complementary part is taken into account then different points of reference
lead to different but equivalent descriptions of the same physical reality.
This is shown at the microscopic as well as at the macroscopic level. A similar
interpretation is valid regarding the "origin dependence" of the reflection
coefficients for reflection on a semi infinite medium. We show that the
"transformation theory" which has been proposed to remedy this situation (and
which is thus not needed) is unphysical since the transformation considered
does not leave the boundary conditions invariant.


title:
Applicability of Modified Effective-Range Theory to positron-atom and
  positron-molecule scattering

abstract:
  We analyze low-energy scattering of positrons on Ar atoms and N2 molecules
using Modified Effective-Range Theory (MERT) developped by O'Malley, Spruch and
Rosenberg [Journal of Math. Phys. 2, 491 (1961)]. We use formulation of MERT
based on exact solutions of Schroedinger equation with polarization potential
rather than low-energy expansions of phase shifts into momentum series. We show
that MERT describes well experimental data, provided that effective-range
expansion is performed both for s- and p-wave scattering, which dominate in the
considered regime of positron energies (0.4 - 2 eV). We estimate the values of
the s-wave scattering lenght and the effective range for e+ - Ar and e+ - N2
collisions.


title: Self-trapping of polychromatic light in nonlinear photonic lattices

abstract:
  We study dynamical reshaping of polychromatic beams due to collective
nonlinear self-action of multiple-frequency components in periodic photonic
lattices and predict the formation of polychromatic discrete solitons
facilitated by localization of light in spectral gaps. We show that the
self-trapping efficiency and structure of emerging polychromatic gap solitons
depends on the spectrum of input beams due to the lattice-enhanced dispersion,
including the effect of crossover from localization to diffraction in media
with defocusing nonlinearity.


title:
Stark effect of the cesium ground state: electric tensor polarizability
  and shift of the clock transition frequency

abstract:
  We present a theoretical analysis of the Stark effect in the hyperfine
structure of the cesium ground-state. We have used third order perturbation
theory, including diagonal and off-diagonal hyperfine interactions, and have
identified terms which were not considered in earlier treatments. A numerical
evaluation using perturbing levels up to n=18 yields new values for the tensor
polarizability $\alpha_2(6S_{1/2})$ and for the Stark shift of the clock
transition frequency in cesium. The polarizabilities are in good agreement with
experimental values, thereby removing a 40-year-old discrepancy. The clock
shift value is in excellent agreement with a recent measurement, but in
contradiction with the commonly accepted value used to correct the black-body
shift of primary frequency standards.


title: Circular conversion dichroism in planar chiral metamaterials

abstract:
  We report the first experiential observation and theoretical analysis of the
new phenomenon of planar chiral circular conversion dichroism, which in some
aspects resembles the Faraday effect in magnetized media, but does not require
the presence of a magnetic field for its observation. It results from the
interaction of an electromagnetic wave with a planar chiral structure patterned
on the sub-wavelength scale, and manifests itself in asymmetric transmission of
circularly polarized waves in the opposite directions through the structure and
elliptically polarized eigenstates. The new effect is radically different from
conventional gyrotropy of three-dimensional chiral media.


title: Ettore Majorana: quantum mechanics of destiny

abstract:
  We show that a number of apparently separate extravagant Majorana's actions,
including those connected with his disappearance are united by the invariant of
behavior. It is based on "carrying into life" the principles of quantum theory.
We argue that the underlying motive force in the story of his disappearance
consisted in existential intention to overcome the fixed frame of personal
identity and dichotomy "life - death" and mimic breakthrough to plurality of
worlds.


title: Exact equivalent-profile formulation for bent optical waveguides

abstract:
  A widespread, intuitive and computationally inexpensive method to analyze
light guidance through waveguide bends is by introducing an equivalent straight
waveguide with refractive index profile modified to account for actual
waveguide bend. Here we revise the commonly used equivalent-index formula,
ending up with its simple extension that enables rigorous treatment of one- and
two-dimensionally confined, uniformly bent waveguides, including tightly coiled
microstructure fibers, curved ridge waveguides and ring microresonators. We
also show that such technique is applicable only to waveguides composed of
isotropic or uniaxially anisotropic materials, with anisotropy axis directed
perpendicular to the curvature plane.


title:
Connecting Blackbody Radiation, Relativity, and Discrete Charge in
  Classical Electrodynamics

abstract:
  It is suggested that an understanding of blackbody radiation within classical
physics requires the presence of classical electromagnetic zero-point
radiation, the restriction to relativistic (Coulomb) scattering systems, and
the use of discrete charge. The contrasting scaling properties of
nonrelativistic classical mechanics and classical electrodynamics are noted,
and it is emphasized that the solutions of classical electrodynamics found in
nature involve constants which connect together the scales of length, time, and
energy. Indeed, there are analogies between the electrostatic forces for groups
of particles of discrete charge and the van der Waals forces in equilibrium
thermal radiation. The differing Lorentz- or Galilean-transformation properties
of the zero-point radiation spectrum and the Rayleigh-Jeans spectrum are noted
in connection with their scaling properties. Also, the thermal effects of
acceleration within classical electromagnetism are related to the existence of
thermal equilibrium within a gravitational field. The unique scaling and
phase-space properties of a discrete charge in the Coulomb potential suggest
the possibility of an equilibrium between the zero-point radiation spectrum and
matter which is universal (independent of the particle mass), and an
equilibrium between a universal thermal radiation spectrum and matter where the
matter phase space depends only upon the ratio mc^2/kT. The observations and
qualitative suggestions made here run counter to the ideas of currently
accepted quantum physics.


title:
Squeezing of open boundaries by Maxwell-consistent real coordinate
  transformation

abstract:
  To simulate open boundaries within finite computation domain, real-function
coordinate transformation in the framework of generally covariant formulation
of Maxwell equations is proposed. The mapping--realized with arctangent
function here--has a transparent geometric meaning of pure squeezing of space,
is admissible by classical electrodynamics, does not introduce artificially
lossy layers (or `lossy coordinates') to absorb outgoing radiation nor leads to
non-Maxwellian fields. At the same time, like for anisotropic perfectly matched
layers, no modification (except for transformation of material tensors) is
needed to existing nearest-neighbor computation schemes, which makes it well
suited for parallel computing implementation.


title:
Dual-Topology Hamiltonian-Replica-Exchange Overlap Histogramming Method
  to Calculate Relative Free Energy Difference in Rough Energy Landscape

abstract:
  A novel overlap histogramming method based on Dual-Topology
Hamiltonian-Replica-Exchange simulation technique is presented to efficiently
calculate relative free energy difference in rough energy landscape, in which
multiple conformers coexist and are separated by large energy barriers. The
proposed method is based on the realization that both DT-HERM exchange
efficiency and confidence of free energy determination in overlap histogramming
method depend on the same criteria: neighboring states' energy derivative
distribution overlap. In this paper, we demonstrate this new methodology by
calculating free energy difference between amino acids: Leucine and Asparagine,
which is an identified chanllenging system for free energy simulations.


title: Wave Equation for Fractal Solid String

abstract:
  We use the fractional integrals to describe fractal solid. We suggest to
consider the fractal solid as special (fractional) continuous medium. We
replace the fractal solid with fractal mass dimension by some continuous model
that is described by fractional integrals. The fractional integrals are
considered as approximation of the integrals on fractals. We derive fractional
generalization of the action functional and the Euler-Lagrange equation for the
fractal solid string.The solution of wave equation for fractal solid string is
considered.


title:
Singularity Theorems in General Relativity: Achievements and Open
  Questions

abstract:
  In this short note, a brief overview with a critical appraisal of the
acclaimed singularity theorems, the most genuine post-Einsteinian result of
General Relativity, is presented.


title: Space-Time Clustering and Correlations of Major Earthquakes

abstract:
  Earthquake occurrence in nature is thought to result from correlated elastic
stresses, leading to clustering in space and time. We show that occurrence of
major earthquakes in California correlates with time intervals when
fluctuations in small earthquakes are suppressed relative to the long term
average. We estimate a probability of less than 1% that this coincidence is due
to random clustering.


title:
Multipole (E1, M1, E2, M2, E3, M3) transition wavelengths and rates
  between 3l5l' excited and ground states in nickel-like ions

abstract:
  A relativistic many-body method is developed to calculate energy and
transition rates for multipole transitions in many-electron ions. This method
is based on relativistic many-body perturbation theory (RMBPT), agrees with
MCDF calculations in lowest-order, includes all second-order correlation
corrections and includes corrections from negative energy states. Reduced
matrix elements, oscillator strengths, and transition rates are calculated for
electric-multipole (dipole (E1), quadrupole (E2), and octupole (E3)) and
magnetic-multipole (dipole (M1), quadrupole (M2), and octupole (M3))
transitions between 3l5l' excited and ground states in Ni-like ions with
nuclear charges ranging from Z = 30 to 100. The calculations start from a
1s22s22p63s23p63d10} Dirac-Fock potential. First-order perturbation theory is
used to obtain intermediate-coupling coefficients, and second-order RMBPT is
used to determine the matrix elements. A detailed discussion of the various
contributions to the dipole matrix elements and energy levels is given for
nickellike tungsten (Z = 74). The contributions from negative-energy states are
included in the second-order E1, M1, E2 M2, E3, and M3 matrix elements. The
resulting transition energies and transition rates are compared with
experimental values and with results from other recent calculations. These
atomic data are important in modeling of M-shell radiation spectra of heavy
ions generated in electron beam ion trap experiments and in M-shell diagnostics
of plasmas.


title: Evolutionary snowdrift game with loners

abstract:
  The effects of an additional strategy or character called loner in the
snowdrift game are studied in a well-mixed population or fully-connected
network and in a square lattice. The snowdrift game, which is a possible
alternative to the prisoner's dilemma game in studying cooperative phenomena in
competing populations, consists of two types of strategies, C (cooperators) and
D (defectors). In a fully-connected network, it is found that either C lives
with D or the loners take over the whole population. In a square lattice, three
possible situations are found: a uniform C-population, C lives with D, and the
coexistence of all three characters. The presence of loners is found to enhance
cooperation in a square lattice by enhancing the payoff of cooperators. The
results are discussed in terms of the effects in restricting a player to
compete only with his nearest neighbors in a square lattice, as opposed to
competing with all players in a fully-connected network.


title: "Breathing" rogue wave observed in numerical experiment

abstract:
  Numerical simulations of the recently derived fully nonlinear equations of
motion for weakly three-dimensional water waves [V.P. Ruban, Phys. Rev. E {\bf
71}, 055303(R) (2005)] with quasi-random initial conditions are reported, which
show the spontaneous formation of a single extreme wave on the deep water. This
rogue wave behaves in an oscillating manner and exists for a relatively long
time (many wave periods) without significant change of its maximal amplitude.


title:
Interpreting Mathematics in Physics: Charting the Applications of SU(2)
  in 20th Century Physics

abstract:
  The role mathematics plays within physics has been of sustained interest for
physicists as well as for philosophers and historians of science. We explore
this topic by tracing the role the mathematical structure associated with SU(2)
has played in three key episodes in 20th century physics - intrinsic spin,
isospin, and gauge theory and electro-weak unification. We also briefly
consider its role in loop quantum gravity. Each episode has led to new physical
notions of a space other than the traditional ones of space and spacetime, and
each has had associated with it a complex and in places, contested history. The
episodes also reveal ways mathematical structures provide resources for new
physical theorizing and we propose our study as a contribution to a need Roger
Penrose has identified to develop a "profoundly sensitive aesthetic" sense for
locating physically relevant mathematics.


title:
Response to Scheuer-Yariv: "A Classical Key-Distribution System based on
  Johnson (like) noise -How Secure?"

abstract:
  We point out that the claims in the comment-paper of Scheuer and Yariv are
either irrelevant or incorrect. The idealized Kirchoff-loop-Johnson-like-noise
(KLJN) scheme is totally secure therefore it is more secure than idealized
quantum communication schemes which can never be totally secure because of the
inherent noise processes in those communication schemes and the statistical
nature of eavesdropper detection based on error statistics. On the other hand,
with sufficient resources, a practical/non-ideal realization of the KLJN cipher
can arbitrarily approach the idealized limit and outperform even the idealized
quantum communicator schemes because the non-ideality-effects are determined
and controlled by the design. The cable resistance issue analyzed by Scheuer
and Yariv is a good example for that because the eavesdropper has insufficient
time window to build a sufficient statistics and the actual information leak
can be designed. We show that Scheuer's and Yariv's numerical result of 1%
voltage drop supports higher security than that of quantum communicators.
Moreover, choosing thicker or shorter wires can arbitrarily reduce this voltage
drop further; the same conclusion holds even according to the equations of
Scheuer and Yariv.


title: Turbulent Cascade of Circulations

abstract:
  The circulation around any closed loop is a Lagrangian invariant for
classical, smooth solutions of the incompressible Euler equations in any number
of space dimensions. However, singular solutions relevant to turbulent flows
need not preserve the classical integrals of motion. Here we generalize the
Kelvin theorem on conservation of circulations to distributional solutions of
Euler and give necessary conditions for the anomalous dissipation of
circulations. We discuss the important role of Kelvin's theorem in turbulent
vortex-stretching dynamics and conjecture a version of the theorem which may
apply to suitable singular solutions.


title: Muon ID- Taking Care of Lower Momenta Muons

abstract:
  In the Muon package under study, the tracks are extrapolated using an
algorithm which accounts for the magnetic field and the ionization (dE/dx). We
improved the calculation of the field dependent term to increase the muon
detection efficiency at lower momenta using a Runge-Kutta method. The muon
identification and hadron separation in b-bbar jets is reported with the
improved software. In the same framework, the utilization of the Kalman filter
is introduced. The principle of the Kalman filter is described in some detail
with the propagation matrix, with the Runge-Kutta term included, and the effect
on low momenta single muons particles is described.


title: Is the Kelvin Theorem Valid for High-Reynolds-Number Turbulence?

abstract:
  The Kelvin-Helmholtz theorem on conservation of circulations is supposed to
hold for ideal inviscid fluids and is believed to be play a crucial role in
turbulent phenomena, such as production of dissipation by vortex
line-stretching. However, this expectation does not take into account
singularities in turbulent velocity fields at infinite Reynolds number. We
present evidence from numerical simulations for the breakdown of the classical
Kelvin theorem in the three-dimensional turbulent energy cascade. Although
violated in individual realizations, we find that circulations are still
conserved in some average sense. For comparison, we show that Kelvin's theorem
holds for individual realizations in the two-dimensional enstrophy cascade, in
agreement with theory. The turbulent ``cascade of circulations'' is shown to be
a classical analogue of phase-slip due to quantized vortices in superfluids and
various applications in geophysics and astrophysics are outlined.


title: Soliton control in fading optical lattices

abstract:
  We predict new phenomena, such as soliton steering and soliton fission, in
optical lattices that fade away exponentially along the propagation direction.
Such lattices, featuring tunable decay rates, arise in photorefractive crystals
in the wavelength range 360-400 nm. We show that the predicted phenomena offer
different opportunities for soliton control.


title:
Long-lived Bloch oscillations with bosonic Sr atoms and application to
  gravity measurement at micrometer scale

abstract:
  We report on the observation of Bloch oscillations on the unprecedented time
scale of severalseconds. The experiment is carried out with ultra-cold bosonic
strontium-88 loaded into a vertical optical standing wave. The negligible
atom-atom elastic cross section and the absence of spin makes $^{88}$Sr an
almost ideal Bose gas insensitive to typical mechanisms of decoherence due to
thermalization and to external stray fields. The small size enables precision
measurements of forces at micrometer scale. This is a challenge in physics for
studies of surfaces, Casimir effects, and searches for deviations from
Newtonian gravity predicted by theories beyond the standard model.


title: Formation of ultracold LiCs molecules

abstract:
  We present the first observation of ultracold LiCs molecules. The molecules
are formed in a two-species magneto-optical trap and detected by two-photon
ionization and time-of-flight mass spectrometry. The production rate
coefficient is found to be in the range $10^{-18}\unit{cm^3s^{-1}}$ to
$10^{-16}\unit{cm^3s^{-1}}$, at least an order of magnitude smaller than for
other heteronuclear diatomic molecules directly formed in a magneto-optical
trap.


title:
Enhanced transmission of light through a gold film due to excitation of
  standing surface plasmon Bloch waves

abstract:
  We have observed enhanced transmission of light through a gold film due to
excitation of standing surface plasmon Bloch waves in a surface Fabry-Perot
resonator. Our experimental results strongly contradict the recently suggested
model of light transmission via excitation of a composite diffractive
evanescent wave.


title: Optical response of metal nanoparticle chains

abstract:
  We study the optical responses of metal nanoparticle chains. Multiple
scattering calculations are used to study the extinction cross sections of
silver nanosphere chains of finite length embedded in a glass matrix. The
transmission and reflection coefficients of periodic 2D arrays of silver
nanospheres are also calculated to understand the interaction between
nanoparticle chains. The results are in agreement with recent experiments. The
splitting of plasmon-resonance modes for different polarizations of the
incident light are explored. Results on the effect of disorder are also
presented.


title:
Photodetachment of H$^{-}$ by a Short Laser Pulse in Crossed Static
  Electric and Magnetic Fields

abstract:
  We present a detailed quantum mechanical treatment of the photodetachment of
H$^{-}$ by a short laser pulse in the presence of crossed static electric and
magnetic fields. An exact analytic formula is presented for the final state
electron wave function (describing an electron in both static electric and
magnetic fields and a short laser pulse of arbitrary intensity). In the limit
of a weak laser pulse, final state electron wave packet motion is examined and
related to the closed classical electron orbits in crossed static fields
predicted by Peters and Delos [Phys. Rev. A \textbf{47}, 3020 (1993)]. Owing to
these closed orbit trajectories, we show that the detachment probability can be
modulated, depending on the time delay between two laser pulses and their
relative phase, thereby providing a means to partially control the
photodetachment process. In the limit of a long, weak pulse (i.e., a
monochromatic radiation field) our results reduce to those of others; however,
for this case we analyze the photodetachment cross section numerically over a
much larger range of electron kinetic energy (i.e., up to 500 cm$^{-1}$) than
in previous studies and relate the detailed structures both analytically and
numerically to the above-mentioned, closed classical periodic orbits.


title:
Scaling relations, virial theorem and energy densities for long-range
  and short-range density functionals

abstract:
  We analyze a decomposition of the Coulomb electron-electron interaction into
a long-range and a short-range part in the framework of density functional
theory, deriving some scaling relations and the corresponding virial theorem.
We study the behavior of the local density approximation in the high-density
limit for the long-range and the short-range functionals by carrying out a
detailed analysis of the correlation energy of a uniform electron gas
interacting via a long-range only electron-electron repulsion. Possible
definitions of exchange and correlation energy densities are discussed and
clarified with some examples.


title:
Local density approximation for long-range or for short-range energy
  functionals?

abstract:
  Density functional methods were developed, in which the Coulomb
electron-electron interaction is split into a long- and a short-range part. In
such methods, one term is calculated using traditional density functional
approximations, like the local density approximation. The present paper tries
to shed some light upon the best way to do it by comparing the accuracy of the
local density approximation with accurate results for the He atom.


title:
Spatially dispersive finite-difference time-domain analysis of
  sub-wavelength imaging by the wire medium slabs

abstract:
  In this paper, a spatially dispersive finite-difference time-domain (FDTD)
method to model wire media is developed and validated. Sub-wavelength imaging
properties of the finite wire medium slabs are examined. It is demonstrated
that the slab with its thickness equal to an integer number of half-wavelengths
is capable of transporting images with sub-wavelength resolution from one
interface of the slab to another. It is also shown that the operation of such
transmission devices is not sensitive to their transverse dimensions, which can
be made even comparable to the wavelength. In this case, the edge diffractions
are negligible and do not disturb the image formation.


title: In-plane Theory of Non-Sequential Triple Ionization

abstract:
  We describe first-principles in-plane calculations of non-sequential triple
ionization (NSTI) of atoms in a linearly polarized intense laser pulse. In a
fully classically correlated description, all three electrons respond
dynamically to the nuclear attraction, the pairwise e-e repulsions and the
laser force throughout the duration of a 780nm laser pulse. Nonsequential
ejection is shown to occur in a multi-electron, possibly multi-cycle and
multi-dimensional, rescattering sequence that is coordinated by a number of
sharp transverse recollimation impacts.


title: Log-normal statistics in e-mail communication patterns

abstract:
  Following up on Barabasi's recent letter to Nature [435, 207--211 (2005)], we
systematically investigate the time series of e-mail usage for 3,188 users at a
university. We focus on two quantities for each user: the time interval between
consecutively sent e-mails (interevent time), and the time interval between
when a user sends an e-mail and when a recipient sends an e-mail back to the
original sender (waiting time). We perform a standard Bayesian model selection
analysis that demonstrates that the interevent times are well-described by a
single log-normal while the waiting times are better described by the
superposition of two log-normals. Our analysis rejects the possibility that
either measure could be described by truncated power-law distributions with
exponent $\alpha \simeq 1$. We also critically evaluate the priority queuing
model proposed by Barab\'asi to describe the distribution of the waiting times.
We show that neither the assumptions nor the predictions of the model are
plausible, and conclude that a theoretical description of human e-mail
communication patterns remains an open problem.


title: Effect of Magnetization Inhomogeneity on Magnetic Microtraps for Atoms

abstract:
  We report on the origin of fragmentation of ultracold atoms observed on a
permanent magnetic film atom chip. A novel technique is used to characterize
small spatial variations of the magnetic field near the film surface using
radio frequency spectroscopy of the trapped atoms. Direct observations indicate
the fragmentation is due to a corrugation of the magnetic potential caused by
long range inhomogeneity in the film magnetization. A model which takes into
account two-dimensional variations of the film magnetization is consistent with
the observations.


title: Detecting degree symmetries in networks

abstract:
  The surrounding of a vertex in a network can be more or less symmetric. We
derive measures of a specific kind of symmetry of a vertex which we call degree
symmetry -- the property that many paths going out from a vertex have
overlapping degree sequences. These measures are evaluated on artificial and
real networks. Specifically we consider vertices in the human metabolic
network. We also measure the average degree-symmetry coefficient for different
classes of real-world network. We find that most studied examples are weakly
positively degree-symmetric. The exceptions are an airport network (having a
negative degree-symmetry coefficient) and one-mode projections of social
affiliation networks that are rather strongly degree-symmetric.


title:
Lorentz Invariant Majorana Formulation of the Field Equations and
  Dirac-like Equation for the Free Photon

abstract:
  In this paper we present a new geometric formulation (Clifford algebra
formalism) of the field equations, which is independent of the reference frame
and of the chosen system of coordinates in it. This formulation deals with the
complex 1-vector $\Psi =E-icB$ ($i$ is the unit imaginary), which is
four-dimensional (4D) geometric generalization of Majorana's complex 3D
quantity $\mathbf{\Psi}=\mathbf{E}-ic\mathbf{B}$. When the sources are absent
the field equations with the complex $\Psi $ become Dirac-like relativistic
wave equations for the free photon. In the frame of ``fiducial'' observers (the
observers who measure fields are at rest) and in the standard basis the
component form of the field equations with 4D $\Psi $ reproduces the component
form of Majorana-Maxwell equations with 3D field $\mathbf{\Psi}$. The important
differences between the approach with the 4D $\Psi $ and that one with the 3D
$\mathbf{\Psi}$ are discussed.


title: Measuring complexity with zippers

abstract:
  Physics concepts have often been borrowed and independently developed by
other fields of science. In this perspective a significant example is that of
entropy in Information Theory. The aim of this paper is to provide a short and
pedagogical introduction to the use of data compression techniques for the
estimate of entropy and other relevant quantities in Information Theory and
Algorithmic Information Theory. We consider in particular the LZ77 algorithm as
case study and discuss how a zipper can be used for information extraction.


title:
On the degeneracy of atomic states within exact-exchange (spin-) density
  functional theory

abstract:
  The problem of degenerate ground states of open-shell atoms is investigated
in spin-restricted and unrestricted density functional theory using the exact
exchange energy functional. For the spin-unrestricted case, spurious energy
splittings of the order of 2 to 3 kcal/mol are found for atoms of the second
and third period which is larger than the splittings obtained from recently
proposed approximate exchange functionals depending explicitly on the current
density. In remarkable contrast, for spin-restricted calculations the
degeneracy of different atomic ground states is recovered to within less than
0.6 kcal/mol.


title:
Bifurcation of Subsonic Gas Flows in the Vicinity of Localized Heat
  Release Regions

abstract:
  Time-accurate simulation of gas dynamic structures resulting in viscous, heat
conducting and radiating gas flows through localized heat release areas is
performed. Cases of intensive heat release in to air at atmospheric pressure
are investigated, whereby the gas is heated up to temperatures 3000-20000 K, so
that local differences of density reach tens and hundreds times. Bifurcation of
the gas dynamic structure has been found at certain relation between gas
velocity and heat release power.


title:
Kilohertz-resolution spectroscopy of cold atoms with an optical
  frequency comb

abstract:
  We have performed sub-Doppler spectroscopy on the narrow intercombination
line of cold calcium atoms using the amplified output of a femtosecond laser
frequency comb. Injection locking of a 657-nm diode laser with a femtosecond
comb allows for two regimes of amplification, one in which many lines of the
comb are amplified, and one where a single line is predominantly amplified. The
output of the laser in both regimes was used to perform kilohertz-level
spectroscopy. This experiment demonstrates the potential for high-resolution
absolute-frequency spectroscopy over the entire spectrum of the frequency comb
output using a single high-finesse optical reference cavity.


title: Universal patterns underlying ongoing wars and terrorism

abstract:
  We report a remarkable universality in the patterns of violence arising in
three high-profile ongoing wars, and in global terrorism. Our results suggest
that these quite different conflict arenas currently feature a common type of
enemy, i.e. the various insurgent forces are beginning to operate in a similar
way regardless of their underlying ideologies, motivations and the terrain in
which they operate. We provide a microscopic theory to explain our main
observations. This theory treats the insurgent force as a generic,
self-organizing system which is dynamically evolving through the continual
coalescence and fragmentation of its constituent groups.


title:
Sub-diffraction light propagation in fibers with anisotropic dielectric
  cores

abstract:
  We present a detailed study of light propagation in waveguides with
anisotropic metamaterial cores. We demonstrate that in contrast to conventional
optical fibers, our structures support free-space-like propagating modes even
when the waveguide radius is much smaller than the wavelength. We develop
analytical formalism to describe mode structure and propagation in strongly
anisotropic systems and study the effects related to waveguide boundaries and
material composition.


title:
Phase and Amplitude Responses of Narrow-Band Optical Filter Measured by
  Microwave Network Analyzer

abstract:
  The phase and amplitude responses of a narrow-band optical filter are
measured simultaneously using a microwave network analyzer. The measurement is
based on an interferometric arrangement to split light into two paths and then
combine them. In one of the two paths, a Mach-Zehnder modulator generates two
tones without carrier and the narrow-band optical filter just passes through
one of the tones. The temperature and environmental variations are removed by
separated phase and amplitude averaging. The amplitude and phase responses of
the optical filter are measured to the resolution and accuracy of the network
analyzer.


title: Consequences of Dirac Theory of the Positron

abstract:
  According to Dirac's theory of the positron, an electromagnetic field tends
to create pairs of particles which leads to a change of Maxwell's equations in
the vacuum. These changes are calculated in the special case that no real
electrons or positrons are present and the field varies little over a Compton
wavelength.


title:
Comment on "Direct Observation of Optical Precursors in a Region of
  Anomalous Dispersion"

abstract:
  We show that the optical transients recently read as "Sommerfeld-Brillouin
precursors" by Jeong, Dawes and Gauthier are not identifiable with optical
precursors (unless one considers that any coherent transient propagating in a
dilute medium at the velocity c is an optical precursor) and that they can be
interpreted in very simple physical terms.


title: Scattering of a Baseball by a Bat

abstract:
  A ball can be hit faster if it is projected without spin but it can be hit
farther if it is projected with backspin. Measurements are presented in this
paper of the tradeoff between speed and spin for a baseball impacting a
baseball bat. The results are inconsistent with a collision model in which the
ball rolls off the bat and instead imply tangential compliance in the ball, the
bat, or both. If the results are extrapolated to the higher speeds that are
typical of the game of baseball, they suggest that a curveball can be hit with
greater backspin than a fastball, but by an amount that is less than would be
the case in the absence of tangential compliance.


title: The Effect of Spin on the Flight of a Baseball

abstract:
  New measurements are presented of the lift on a spinning baseball. The
experiment utilizes a pitching machine to project the baseball horizontally; a
high-speed motion capture system to measure the initial velocity and angular
velocity and to track the trajectory over ~5 m of flight; and a ruler to
measure the total distance traversed by the ball. Speeds in the range v=50-110
mph and spin rates (topspin or backspin)in the range omega=1500-4500 rpm were
utilized, corresponding to Reynold's numbers Re=(1.1-2.4) x 10^5 and spin
parameters R*omega/v=0.1-0.6. Standard least-squares fitting procedures were
used to extract the initial parameters of the trajectory and to determine the
lift and drag coefficients. Comparison is made with previous measurements or
parametrizations of the lift and drag coefficients, and implications for the
effect of spin on the flight of a long fly ball are discussed.


title: Resolved Hubble Space spectroscopy of ultracool binary systems

abstract:
  Using the low-resolution mode of the Space Telescope Imaging Spectrograph
(STIS) aboard the \emph{Hubble Space Telescope} (HST), we have obtained
spatially resolved spectra of 20 ultracool dwarfs. 18 of them belong to 9 known
very low-mass binary systems with angular separations in the range 0.37-0.098
arcseconds. We have derived spectral types in the range dM7.5 to dL6 from the
PC3 index, and by comparing our STIS spectra with ground-based spectra of
similar spectral resolution from Mart{\'\i}n et al. (1999). We have searched
for H$_\alpha$ emission in each object but it was clearly detected in only 2 of
them. We find that the distribution of H$_\alpha$ emission in our sample is
statistically different from that of single field dwarfs, suggesting an
intriguing anticorrelation between chromospheric activity and binarity for
M7--M9.5 dwarfs. We provide measuments of the strength of the main photospheric
features and the PC3 index, and we derive calibrations of spectral subclasses
versus F814W and K-band absolute magnitudes for a subset of 10 dwarfs in 5
binaries that have known trigonometric parallaxes.


title: What is the meaning of lifetime measurement?

abstract:
  The lifetime measurement of molecular excited state has been the subject of
many papers and experiments. Very often the experimental data are fitted by
single or bi exponential decays which in many case is the best fit that can be
done owing the signal to noise ratio. The times constants obtained from these
fit are often discussed in term of one species associated with one lifetime:
depending on the studied system, the species can be one type of molecule, one
isomer from a given molecule or local environment. How justified is this
assumption?