title: On the Rotational and Machian Properties of the Universe

abstract:
  We find a Classical explanation on the origin of the Cosmological "constant"
term, as a rotating feature of the Universe. We give a picture on "creation" of
the Universe. By analogy with the original Brans-Dicke relation, several other
similar relations were obtained in a previous paper (Berman, 2007d), which we
now extend, by relating the angular momentum L, absolute temperature T, and the
cosmological "constant", with R, where R, M stand for the radius (scale-factor)
and the mass of the causally related Universe. We show here that these
properties, which characterize Machian Universes, can be put in the form of
equalities, which can be derived, from the conjecture that the total energy of
the Universe is null, alike with the effective energy density, and we therefore
imply that R depends linearly with M ; the angular momentum runs like squared R
; T, like R to the power -1/2 ; lambda, as R to the power -2 so that the total
entropy of the Universe grows with R to the power 3/2, and, then, also as M to
the power 3/2. The "loss of information paradox", for black holes, is
dismantled. It must be obvious, from this paper, that each type of energy
contribution, to the total energy of the Universe, divided by M multiplied by
c-squared, yields a constant, during all times, so that, for instance, if the
present contribution of the cosmological "constant", drives the present
Universe, it also must have driven alike, in all the lifespan of the Machian
Universe: the relative contributions of densities of each kind, towards the
total density, remain the same during all times. Berman (2008; 2008a; 2008b)
found similar hidden rotational states of the Universe in Relativistic theories
which obey Robertson-Walker's metric.


title:
Effect of Coherence on Radiation Forces acting on a Rayleigh Dielectric
  Sphere

abstract:
  The radiation forces on a Rayleigh dielectric sphere induced by a partially
coherent light beam are greatly affected by the coherence of the light beam.
The magnitude of the radiation forces on a dielectric sphere near the focus
point greatly decreases as the coherence decreases. For the light beam with
good coherence, the radiation force may be used to trap a particle; and for the
light beam with intermediate coherence, the radiation force may be used to
guide and accelerate a particle.


title: Track Reconstruction and Alignment with the CMS Silicon Tracker

abstract:
  This report presents recent results on track reconstruction and alignment
with the silicon tracker of the CMS experiment at the LHC, obtained with a full
detector simulation. After an overview of the layout of the tracker and its
material budget, the baseline algorithm for track reconstruction is discussed.
The performance of the track reconstruction and its dependence on misalignment
is shown. The concept for alignment of the CMS tracker, using a laser alignment
system as well as three different track-based alignment algorithms, is
presented.


title: Artifacts with uneven sampling of red noise

abstract:
  The vast majority of sampling systems operate in a standard way: at each tick
of a fixed-frequency master clock a digitizer reads out a voltage that
corresponds to the value of some physical quantity and translates it into a bit
pattern that is either transmitted, stored, or processed right away. Thus
signal sampling at evenly spaced time intervals is the rule: however this is
not always the case, and uneven sampling is sometimes unavoidable.
  While periodic or quasi-periodic uneven sampling of a deterministic signal
can reasonably be expected to produce artifacts, it is much less obvious that
the same happens with noise: here I show that this is indeed the case only for
long-memory noise processes, i.e., power-law noises $1/f^\alpha$ with $\alpha >
2$. The resulting artifacts are usually a nuisance although they can be
eliminated with a proper processing of the signal samples, but they could also
be turned to advantage and used to encode information.


title: Possible Pressure Waves of Supersolid Helium at High Pressure

abstract:
  We make comments on Kim and Chan's [{\it Phys. Rev. Lett.} 97, 115302 (2006)]
letter. Based on their pressure-dependent measurements (by a torsional
oscillator technique), we propose that the {\it supersolid} fraction
($\rho_s/\rho$) might be relevant to an sound absorption or attenuation
(fluctuations of pressure waves) in microscopic domain since there is no
apparent change in $T_c$ with pressure.


title:
Breaking of Energy Conservation Law: Creating and Destroying of Energy
  by Subwavelength Nanosystems

abstract:
  The extra energy, negative energy and annihilation of energy by the
subwavelength conservative systems that have a wave nature of light or matter
(quantum) objects are predicted. The creating and destroying of energy break
the energy conservation law in any subwavelength physical system. The
paradoxical phenomenon is demonstrated in the context of extraordinary
transmission of light and matter through subwavelength apertures [T.W. Ebbesen
et al., Nature (London) 391, 667 (1998) and E. Moreno et al., Phys. Rev. Lett.
95, 170406 (2005)].


title:
Indoor and Outdoor in Situ High-Resolution Gamma Radiation Measurements
  in Urban Areas of Cyprus

abstract:
  In situ, high-resolution, gamma-ray spectrometry of a total number of 70
outdoor and 20 indoor representative measurements were performed in
preselected, common locations of the main urban areas of Cyprus. Specific
activities and gamma absorbed dose rates in air due to the naturally occurring
radionuclides of Th-232 and U-238 series, and K-40 are determined and
discussed. Effective dose rate to the Cyprus population due to terrestrial
gamma radiation is derived directly from this work. The results obtained
outdoors match very well with those derived previously by high-resolution gamma
spectrometry of soil samples, which were collected from the main island bedrock
surface. This implies that the construction and building materials in urban
areas do not affect the external gamma dose rate; thus they are mostly of local
origin. Finally, the indoor/outdoor gamma dose ratio was found to be 1.4 +-
0.5.


title: Electromagnetic field of fractal distribution of charged particles

abstract:
  Electric and magnetic fields of fractal distribution of charged particles are
considered. The fractional integrals are used to describe fractal distribution.
The fractional integrals are considered as approximations of integrals on
fractals. Using the fractional generalization of integral Maxwell equation, the
simple examples of the fields of homogeneous fractal distribution are
considered. The electric dipole and quadrupole moments for fractal distribution
are derived.

categories: physics.plasm-ph astro-ph cond-mat.mtrl-sci physics.class-ph


title:
On the Unfathomableness of Consciousness by Consciousness: Why do
  physicists widely agree on the assured extent of their professional
  knowledge, but not so philosophers? An exchange of letters with Carl
  Friedrich von Weizsaecker

abstract:
  On the occasion of Carl Friedrich von Weizsaecker's 81st birthday, a
colloquium was held on July 3, 1993. One of the topics was "The epistemological
foundation of physics from Kant to von Weizsaecker". I took part in the
discussion. Afterwards I got the impression that I had not succeeded in making
my points clear. Therefore, I wrote an explanatory letter to Prof. von
Weizsaecker. This was the beginning of a correspondence on the questions
intimated by the title above. In addition, a private discussion between Prof.
von Weizsaecker and myself took place. Some readers may be interested in the
answers which Carl Friedrich von Weizsaecker has given to the naive questions
and views of a physicist with only a rudimentary education in philosophy. The
starting point of our discussion was my remark that the conspicuous inability
of philosophers to agree on the deepest elements of human existence including
the basic questions of ethics, which is tantamount to the occurrence of
different schools of philosophy competing with each other, could perhaps be
traced back to the fundamental inability of man to attain self-knowledge.
Physicists, on the other hand, can reach consent, in an equally remarkable way,
on the results of their measurements and on whether or not these results agree
with the ideas of theory. They just have to deal with res extensa. Here the
yardstick does not intend to measure itself, but objects which are external to
it, and this is possible. There remains only the question what consequences can
be drawn from this realization. Is philosophy, in as much as it gives
statements on the totality of human existence, only an expression of the
prevailing social circumstances and views, interesting enough as such, but not
a gateway to truth?


title:
Terahertz surface plasmon polariton propagation and focusing on
  periodically corrugated metal wires

abstract:
  In this letter we show how the dispersion relation of surface plasmon
polaritons (SPPs) propagating along a perfectly conducting wire can be tailored
by corrugating its surface with a periodic array of radial grooves. In this
way, highly localized SPPs can be sustained in the terahertz region of the
electromagnetic spectrum. Importantly, the propagation characteristics of these
spoof SPPs can be controlled by the surface geometry, opening the way to
important applications such as energy concentration on cylindrical wires and
superfocusing using conical structures.


title:
Hydrogen atom in crossed electric and magnetic fields: Phase space
  topology and torus quantization via periodic orbits

abstract:
  A hierarchical ordering is demonstrated for the periodic orbits in a strongly
coupled multidimensional Hamiltonian system, namely the hydrogen atom in
crossed electric and magnetic fields. It mirrors the hierarchy of broken
resonant tori and thereby allows one to characterize the periodic orbits by a
set of winding numbers. With this knowledge, we construct the action variables
as functions of the frequency ratios and carry out a semiclassical torus
quantization. The semiclassical energy levels thus obtained agree well with
exact quantum calculations.


title:
Methods of Using Existing Wire Lines (power lines, phone lines, internet
  lines) for Totally Secure Classical Communication Utilizing Kirchoff's Law
  and Johnson-like Noise

abstract:
  We outline some general solutions to use already existing and currently used
wire lines, such as power lines, phone lines, internet lines, etc, for the
unconditionally secure communication method based on Kirchoff's Law and
Johnson-like Noise (KLJN). Two different methods are shown. One is based on
filters used at single wires and the other one utilizes a common mode voltage
superimposed on a three-phase powerline.


title: Matrix formalism of synchrobetatron coupling

abstract:
  In this paper we present a complete linear synchrobetatron coupling formalism
by studying the transfer matrix which describes linear horizontal and
longitudinal motions. With the technique established in the linear
horizontal-vertical coupling study [D. Sagan and D. Rubin, Phys. Rev. ST Accel.
Beams {\bf 2}, 074001 (1999)], we found a transformation to block diagonalize
the transfer matrix and decouple the betatron motion and the synchrotron
motion. By separating the usual dispersion term from the horizontal coordinate
first, we were able to obtain analytic expressions of the transformation under
reasonable approximations. We also obtained the perturbations to the betatron
tune and the Courant-Snyder functions. The closed orbit changes due to finite
energy gains at rf cavities and radiation energy losses were also studied by
the 5$\times$5 extended transfer matrix with the fifth column describing kicks
in the 4-dimension phase space.


title: Zonal flow generation by modulational instability

abstract:
  This paper gives a pedagogic review of the envelope formalism for excitation
of zonal flows by nonlinear interactions of plasma drift waves or Rossby waves,
described equivalently by the Hasegawa-Mima (HM) equation or the
quasigeostrophic barotropic potential vorticity equation, respectively. In the
plasma case a modified form of the HM equation, which takes into account
suppression of the magnetic-surface-averaged electron density response by a
small amount of rotational transform, is also analyzed. Excitation of zonal
mean flow by a modulated wave train is particularly strong in the modified HM
case. A local dispersion relation for a coherent wave train is calculated by
linearizing about a background mean flow and used to find the nonlinear
frequency shift by inserting the nonlinearly excited mean flow. Using the
generic nonlinear Schroedinger equation about a uniform carrier wave, the
criterion for instability of small modulations of the wave train is found, as
is the maximum growth rate and phase velocity of the modulations and zonal
flows, in both the modified and unmodified cases.


title:
New final doublets and power densities for the ILC small crossing angle
  layout

abstract:
  In this paper we use current and proposed final doublet magnet technologies
to reoptimise the interaction region of the International Linear Collider and
reduce the power losses. The result is a set of three new final doublet layouts
with improved beam transport properties. The effect of localised power
deposition is considered, and its reduction using Tungsten liners.


title: Error and Attack Tolerance of Layered Complex Networks

abstract:
  Many complex systems may be described not by one, but by a number of complex
networks mapped one on the other in a multilayer structure. The interactions
and dependencies between these layers cause that what is true for a distinct
single layer does not necessarily reflect well the state of the entire system.
In this paper we study the robustness of three real-life examples of two-layer
complex systems that come from the fields of communication (the Internet),
transportation (the European railway system) and biology (the human brain). In
order to cover the whole range of features specific to these systems, we focus
on two extreme policies of system's response to failures, no rerouting and full
rerouting. Our main finding is that multilayer systems are much more vulnerable
to errors and intentional attacks than they seem to be from a single layer
perspective.


title:
Enhanced Transmission and Reflection of Femtosecond Pulses by a Single
  Slit

abstract:
  We show that a physical mechanism responsible for the enhanced transmission
and reflection of femtosecond pulses by a single subwavelength nanoslit in a
thick metallic film is the Fabry-Perot-like resonant excitation of stationary,
quasistationary and nonstationary waves inside the slit, which leads to the
field enhancement inside and around the slit. The mechanism is universal for
any pulse-scatter system, which supports the stationary resonances. We point
out that there is a pulse duration limit below which the slit does not support
the intraslit resonance.


title: Some Variations on Maxwell's Equations

abstract:
  In the first sections of this article, we discuss two variations on Maxwell's
equations that have been introduced in earlier work--a class of nonlinear
Maxwell theories with well-defined Galilean limits (and correspondingly
generalized Yang-Mills equations), and a linear modification motivated by the
coupling of the electromagnetic potential with a certain nonlinear Schroedinger
equation. In the final section, revisiting an old idea of Lorentz, we write
Maxwell's equations for a theory in which the electrostatic force of repulsion
between like charges differs fundamentally in magnitude from the electrostatic
force of attraction between unlike charges. We elaborate on Lorentz'
description by means of electric and magnetic field strengths, whose governing
equations separate into two fully relativistic Maxwell systems--one describing
ordinary electromagnetism, and the other describing a universally attractive or
repulsive long-range force. If such a force cannot be ruled out {\it a priori}
by known physical principles, its magnitude should be determined or bounded
experimentally. Were it to exist, interesting possibilities go beyond Lorentz'
early conjecture of a relation to (Newtonian) gravity.


title: Gravity-free hydraulic jumps and metal femtocups

abstract:
  Hydraulic jumps created by gravity are seen every day in the kitchen sink. We
show that at small scales a circular hydraulic jump can be created in the
absence of gravity, by surface tension. The theory is motivated by our
experimental finding of a height discontinuity in spreading submicron molten
metal droplets created by pulsed-laser ablation. By careful control of initial
conditions, we show that this leads to solid femtolitre cups of gold, silver,
copper, niobium and tin.


title:
Compression and localization of an atomic cloud in a time dependent
  optical lattice

abstract:
  We analyze a method of compressing a cloud of cold atoms by dynamic control
of a far off resonance optical lattice. We show that by reducing the lattice
spacing either continuously or in discrete steps while cooling the atoms with
optical molasses large compression factors can be achieved. Particle motion in
the time dependent lattice is studied numerically using a three dimensional
semiclassical model. Two experimentally realistic models are analyzed. In the
first we continuously vary the lattice beam angles to compress atoms initially
in a Gaussian distributed cloud with standard deviation of $250 \mu\rm m$ into
a single site of a two-dimensional lattice of area $A\sim 35\times 35
\lambda^2$, with $\lambda$ the wavelength of the lattice beams. This results in
an optical depth for an on-resonant probe beam $>80$ which is an increase by a
factor of about 1800 compared to the uncompressed cloud. In the second approach
we use a discrete set of lattice beam angles to decrease the spatial scale of
the cloud by a factor of 500, and localize a few atoms to a single lattice site
with an area $A\stackrel{<}{\sim} \lambda^2.$


title: Unexpected volatility and intraday serial correlation

abstract:
  We study the impact of volatility on intraday serial correlation, at time
scales of less than 20 minutes, exploiting a data set with all transaction on
SPX500 futures from 1993 to 2001. We show that, while realized volatility and
intraday serial correlation are linked, this relation is driven by unexpected
volatility only, that is by the fraction of volatility which cannot be
forecasted. The impact of predictable volatility is instead found to be
negative (LeBaron effect). Our results are robust to microstructure noise, and
they confirm the leading economic theories on price formation.


title: Fugacity of condensed media

abstract:
  Appearance of physical properties of objects is a basic for their detection
in a media. Fugacity is a physical property of objects. Definition of
estimations fugacity for different objects can be executed on model which
principle of construction is considered in this paper. The model developed by
us well-formed with classical definition fugacity and open up possibilities for
calculation of physical "fugacity" for elementary and compound substances.


title: Frozen light in photonic crystals with degenerate band edge

abstract:
  Consider a plane monochromatic wave incident on a semi-infinite periodic
structure. What happens if the normal component of the transmitted wave group
velocity vanishes? At first sight, zero normal component of the transmitted
wave group velocity simply implies total reflection of the incident wave. But
we demonstrate that total reflection is not the only possible outcome. Instead,
the transmitted wave can appear in the form of a frozen mode with very large
diverging amplitude and either zero, or purely tangential energy flux. The
field amplitude in the transmitted wave can exceed that of the incident wave by
several orders of magnitude. There are two qualitatively different kinds of
frozen mode regime. The first one is associated with a stationary inflection
point of electromagnetic dispersion relation. This phenomenon has been analyzed
in our previous publications. Now, our focus is on the frozen mode regime
related to a degenerate photonic band edge. An advantage of this new phenomenon
is that it can occur in much simpler periodic structures. This spectacular
effect is extremely sensitive to the frequency and direction of propagation of
the incident plane wave. These features can be very attractive in a variety
practical applications, such as higher harmonic generation and wave mixing,
light amplification and lasing, highly efficient superprizms, etc.


title: The value of information in a multi-agent market model

abstract:
  We present an experimental and simulated model of a multi-agent stock market
driven by a double auction order matching mechanism. Studying the effect of
cumulative information on the performance of traders, we find a non monotonic
relationship of net returns of traders as a function of information levels,
both in the experiments and in the simulations. Particularly, averagely
informed traders perform worse than the non informed and only traders with high
levels of information (insiders) are able to beat the market. The simulations
and the experiments reproduce many stylized facts of stock markets, such as
fast decay of autocorrelation of returns, volatility clustering and fat-tailed
distribution of returns. These results have an important message for everyday
life. They can give a possible explanation why, on average, professional fund
managers perform worse than the market index.


title:
Transport of launched cold atoms with a laser guide and pulsed magnetic
  fields

abstract:
  We propose the novel combination of a laser guide and magnetic lens to
transport a cold atomic cloud. We have modelled the loading and guiding of a
launched cloud of cold atoms with the optical dipole force. We discuss the
optimum strategy for loading typically 30% of the atoms from a MOT and guiding
them vertically through 22cm. However, although the atoms are tightly confined
transversely, thermal expansion in the propagation direction still results in a
density loss of two orders of magnitude. By combining the laser guide with a
single impulse from a magnetic lens we show one can actually increase the
density of the guided atoms by a factor of 10.


title:
Hands-on Gravitational Wave Astronomy: Extracting astrophysical
  information from simulated signals

abstract:
  In this paper we introduce a hands-on activity in which introductory
astronomy students act as gravitational wave astronomers by extracting
information from simulated gravitational wave signals. The process mimics the
way true gravitational wave analysis will be handled by using plots of a pure
gravitational wave signal. The students directly measure the properties of the
simulated signal, and use these measurements to evaluate standard formulae for
astrophysical source parameters. An exercise based on the discussion in this
paper has been written and made publicly available online for use in
introductory laboratory courses.


title:
Kinetic Enhancement of Raman Backscatter, and Electron Acoustic Thomson
  Scatter

abstract:
  1-D Eulerian Vlasov-Maxwell simulations are presented which show kinetic
enhancement of stimulated Raman backscatter (SRBS) due to electron trapping in
regimes of heavy linear Landau damping. The conventional Raman Langmuir wave is
transformed into a set of beam acoustic modes [L. Yin et al., Phys. Rev. E 73,
025401 (2006)]. For the first time, a low phase velocity electron acoustic wave
(EAW) is seen developing from the self-consistent Raman physics. Backscatter of
the pump laser off the EAW fluctuations is reported and referred to as electron
acoustic Thomson scatter. This light is similar in wavelength to, although much
lower in amplitude than, the reflected light between the pump and SRBS
wavelengths observed in single hot spot experiments, and previously interpreted
as stimulated electron acoustic scatter [D. S. Montgomery et al., Phys. Rev.
Lett. 87, 155001 (2001)]. The EAW is strongest well below the phase-matched
frequency for electron acoustic scatter, and therefore the EAW is not produced
by it. The beating of different beam acoustic modes is proposed as the EAW
excitation mechanism, and is called beam acoustic decay. Supporting evidence
for this process, including bispectral analysis, is presented. The linear
electrostatic modes, found by projecting the numerical distribution function
onto a Gauss-Hermite basis, include beam acoustic modes (some of which are
unstable even without parametric coupling to light waves) and a strongly-damped
EAW similar to the observed one. This linear EAW results from non-Maxwellian
features in the electron distribution, rather than nonlinearity due to electron
trapping.


title: Radiation Hazard of Relativistic Interstellar Flight

abstract:
  From the point of view of radiation safety, interstellar space is not an
empty void. Interstellar gas and cosmic rays, which consist of hydrogen and
helium nucleons, present a severe radiation hazard to crew and electronics
aboard a relativistic interstellar ship. Of the two, the oncoming relativistic
flow of interstellar gas produces the most intence radiation. A protection
shield will be needed to block relativistic interstellar gas that can also
absorb most of the cosmic rays which, as a result of relativistic aberration,
form into a beamed flow propagating toward the front of the ship.


title: Messaging to Extra-Terrestrial Intelligence

abstract:
  Throughout the entire history of terrestrial civilization, only four projects
involving transmitting of interstellar radio messages (IRMs) have yet been
fully developed and realized. Nevertheless, we should understand a simple thing
-- if all civilizations in the Universe are only recipients, and not
message-sending civilizations, than no SETI searches make any sense. We present
the theory and methodology of composing and transmitting of future IRMs.


title:
Exact Keldysh theory of strong-field ionization: residue method vs
  saddle-point approximation

abstract:
  In recent articles [Mishima et al., Phys. Rev. A, 66, 033401(2002); Chao,
Phys. Rev. A, 72, 053414 (2005)] it was proposed to use the residue theorem for
the exact calculation of the transition amplitude describing strong-field
ionization of atomic systems within Keldysh theory. This should avoid the
necessity to apply the method of steepest descent (saddle-point approximation).
Comparing the results of both approaches for atomic hydrogen a difference by a
factor of 2 was found for the 1s, and an even more drastic deviation for the 2s
state. Thus it was concluded that the use of the saddle-point approximation is
problematic. In this work the deviations are explained and it is shown that the
previous conclusion is based on an unjustified neglect of an important
contribution occurring in the application of the residue theorem. Furthermore,
the applicability of the method of steepest descent for the ionization of
Rydberg states is discussed and an improvement of the standard result is
suggested that successfully removes the otherwise drastic failure for large
principal quantum numbers.


title:
Numerical solution of perturbed Kepler problem using a split operator
  technique

abstract:
  An efficient geometric integrator is proposed for solving the perturbed
Kepler motion. This method is stable and accurate over long integration time,
which makes it appropriate for treating problems in astrophysics, like solar
system simulations, and atomic and molecular physics, like classical
simulations of highly excited atoms in external fields. The key idea is to
decompose the hamiltonian in solvable parts and propagate the system according
to each term. Two case studies, the Kepler atom in an uniform field and in a
monochromatic field, are presented and the errors are analyzed.


title:
About the connection between vacuum birefringence and the light-light
  scattering amplitude

abstract:
  Birefringence phenomena stemming from vacuum polarization are revisited in
the framework of coherent scattering. Based on photon-photon scattering, our
analysis brings out the direct connection between this process and vacuum
birefringence. We show how this procedure can be extended to the Kerr and the
Cotton-Mouton birefringences in vacuum, thus providing a unified treatment of
various polarization schemes, including those involving static fields.


title:
Pump-probe measurement of atomic parity violation in caesium with a
  precision of 2.6%

abstract:
  We present the atomic parity violation measurements made in Cs vapour using a
pump-probe scheme. After pulsed excitation of the 6S-7S forbidden transition in
the presence of a longitudinal electric field, a laser beam resonant with one
of the 7S-6P transitions stimulates the 7S atom emission for a duration of 20
ns. The polarisation of the amplified probe beam is analysed. A seven-fold
signature allows discrimination of the parity violating linear dichroism, and
real-time calibration by a similar, known, parity conserving linear dichroism.
The zero-field linear dichroism signal due to the magnetic dipole transition
moment is observed for the first time, and used for in-situ determination of
the electric field. The result, ImE1^{pv}= (-808+/- 21) 10^{-14} ea\_{0}, is in
perfect agreement with the corresponding, more precise measurement obtained by
the Boulder group. A transverse field configuration with large probe
amplification could bring atomic parity violation measurements to the 0.1%
accuracy level.


title:
Arrangement of a 4Pi microscope for reducing the confocal detection
  volume with two-photon excitation

abstract:
  The main advantage of two-photon fluorescence confocal microscopy is the low
absorption obtained with live tissues at the wavelengths of operation. However,
the resolution of two-photon fluorescence confocal microscopes is lower than in
the case of one-photon excitation. The 4Pi microscope type C working in
two-photon regime, in which the excitation beams are coherently superimposed
and, simultaneously, the emitted beams are also coherently added, has shown to
be a good solution for increasing the resolution along the optical axis and for
reducing the amplitude of the side lobes of the point spread function. However,
the resolution in the transverse plane is poorer than in the case of one-photon
excitation due to the larger wavelength involved in the two-photon fluorescence
process. In this paper we show that a particular arrangement of the 4Pi
microscope, referenced as 4Pi0 microscope, is a solution for obtaining a
lateral resolution in the two-photon regime similar or even better to that
obtained with 4Pi microscopes working in the one-photon excitation regime.


title:
Influence of the Raman depolarisation ratio on far-field radiation
  patterns in coherent anti-Stokes Raman scattering (CARS) microscopy

abstract:
  We propose a full-vectorial numerical study of far field radiation patterns
in coherent anti-Stokes Raman scattering (CARS) microscopy. We emphasis the
particular role of the Raman depolarisation ratio of the observed medium and
show how it modifies the radiation pattern of thin objects.


title: The capacitance of pristine ice crystals and aggregate snowflakes

abstract:
  A new method of accurately calculating the capacitance of realistic ice
particles is described: such values are key to accurate estimates of deposition
and evaporation rates in NWP models. The trajectories of diffusing water
molecules are directly sampled, using random `walkers'. By counting how many of
these trajectories intersect the surface of the ice particle (which may be any
shape) and how many escape outside a spherical boundary far from the particle,
the capacitance of a number of model ice particle habits have been estimated,
including hexagonal columns and plates, `scalene' columns and plates, bullets,
bullet-rosettes, dendrites, and realistic aggregate snowflakes. For ice
particles with sharp edges and corners this method is an efficient and
straightforward way of solving Laplace's equation for the capacitance. Provided
that a large enough number of random walkers are used to sample the particle
geometry the authors expect the calculated capacitances to be accurate to
within ~1%. The capacitance for our modelled aggregate snowflakes (C/Dmax=0.25,
normalised by the maximum dimension Dmax) is shown to be in close agreement
with recent aircraft measurements of snowflake sublimation rates. This result
shows that the capacitance of a sphere (C/Dmax=0.5) which is commonly used in
numerical models, overestimates the evaporation rate by a factor of 2. The
effect of vapor `screening' by crystals growing in the vicinity of one another
has also been investigated. The results clearly show that neighbouring crystals
growing on a filament in cloud chamber experiments can strongly constrict the
vapor supply to each other, and the resulting growth rate measurements may
severely underestimate the rate for a single crystal in isolation (by a factor
of 3 in our model setup).


title: Counterposition and negative refraction due to uniform motion

abstract:
  Refraction of obliquely incident plane waves due to the interface of a
vacuous half-space and a half-space occupied by a simply moving,
nondissipative, isotropic dielectric-magnetic medium is considered, when the
medium's velocity lies parallel to the interface and in the plane of incidence.
Counterposition of the refracted wavevector and time-averaged Poynting vector
occurs when the medium's velocity is sufficiently large in magnitude and makes
an obtuse angle with the incident wavevector. The counterposition induced by
relative motion occurs whether the refraction is negative or positive when the
medium is at rest.


title:
Morphological Instability and Cancer Invasion: A 'Splashing Water Drop'
  Analogy

abstract:
  We present an analogy between two unrelated instabilities. One is caused by
the impact of a drop of water on a solid surface while the other one concerns a
tumor that develops invasive cellular branches into the surrounding host
tissue. In spite of the apparent abstractness of the idea, it yields a very
practical result, i.e. an index that predicts tumor invasion based on a few
measurable parameters. We discuss its application in the context of
experimental data and suggest potential clinical implications.


title:
A high-resolution infrared spectroscopic investigation of the halogen
  atom-HCN entrance channel complexes solvated in superfluid helium droplets

abstract:
  Rotationally resolved infrared spectra are reported for the X-HCN (X = Cl,
Br, I) binary complexes solvated in helium nanodroplets. These results are
directly compared with that obtained previously for the corresponding X-HF
complexes [J. M. Merritt, J. K\"upper, and R. E. Miller, PCCP, 7, 67 (2005)].
For bromine and iodine atoms complexed with HCN, two linear structures are
observed and assigned to the $^{2}\Sigma_{1/2}$ and $^{2}\Pi_{3/2}$ ground
electronic states of the nitrogen and hydrogen bound geometries, respectively.
Experiments for HCN + chlorine atoms give rise to only a single band which is
attributed to the nitrogen bound isomer. That the hydrogen bound isomer is not
stabilized is rationalized in terms of a lowering of the isomerization barrier
by spin-orbit coupling. Theoretical calculations with and without spin-orbit
coupling have also been performed and are compared with our experimental
results. The possibility of stabilizing high-energy structures containing
multiple radicals is discussed, motivated by preliminary spectroscopic evidence
for the di-radical Br-HCCCN-Br complex. Spectra for the corresponding molecular
halogen HCN-X$_{2}$ complexes are also presented.


title: Casimir vacuum energy and the semiclassical electron

abstract:
  In 1953 Casimir proposed a semiclassical model for the electron based on the
concept that net inward radiation pressure from the electromagnetic vacuum
fluctuations fields (as in the Casimir effect, generally) might play the role
of Poincare stresses, compensating outward coulomb pressure to yield a stable
configuration at small dimensions. Given that in scattering experiments the
electron appears point-like, critical to the success of the proposed model is
demonstration that the self-energy corresponding to the divergent coulomb field
does not contribute to the electron mass. Here we develop a self-consistent,
vacuum-fluctuation-based model that satisfies this requirement and thereby
resolves the issue of what would otherwise appear to be an incompatibility
between a point-like electron and finite mass.


title: Concealment by uniform motion

abstract:
  The perceived lateral position of a transmitted beam, upon propagating
through a slab made of homogeneous, isotropic, dielectric material at an
oblique angle, can be controlled through varying the velocity of the slab. In
particular, by judiciously selecting the slab velocity, the transmitted beam
can emerge from the slab with no lateral shift in position. Thereby, a degree
of concealment can be achieved. This concealment is explored in numerical
calculations based on a 2D Gaussian beam.


title: Femtosecond Diffractive Imaging with a Soft-X-ray Free-Electron Laser

abstract:
  Theory predicts that with an ultrashort and extremely bright coherent X-ray
pulse, a single diffraction pattern may be recorded from a large macromolecule,
a virus, or a cell before the sample explodes and turns into a plasma. Here we
report the first experimental demonstration of this principle using the FLASH
soft X-ray free-electron laser. An intense 25 fs, 4 10^13 W/cm^2 pulse,
containing 10^12 photons at 32 nm wavelength, produced a coherent diffraction
pattern from a nano-structured non-periodic object, before destroying it at
60,000 K. A novel X-ray camera assured single photon detection sensitivity by
filtering out parasitic scattering and plasma radiation. The reconstructed
image, obtained directly from the coherent pattern by phase retrieval through
oversampling, shows no measurable damage, and extends to diffraction-limited
resolution. A three-dimensional data set may be assembled from such images when
copies of a reproducible sample are exposed to the beam one by one.


title: The existence of a 2Po excited state for the e+Ca system

abstract:
  The Configuration Interaction method is used to demonstrate that there is an
electronically stable state of positronic calcium with an orbital angular
momentum of L=1. This prediction relies on the use of an asymptotic series to
estimate the variational limit of the energy. The best estimate of the binding
energy is 37 meV. A discussion of the structure of the system is also
presented.


title: On the Reality of Minkowski Space

abstract:
  Should physicists deal with the question of the reality of Minkowski space
(or any relativistic spacetime)? It is argued that they should since this is a
question about the dimensionality of the world at the macroscopic level and it
is physics that should answer it.


title: Volatility and dividend risk in perpetual American options

abstract:
  American options are financial instruments that can be exercised at any time
before expiration. In this paper we study the problem of pricing this kind of
derivatives within a framework in which some of the properties --volatility and
dividend policy-- of the underlaying stock can change at a random instant of
time, but in such a way that we can forecast their final values. Under this
assumption we can model actual market conditions because some of the most
relevant facts that may potentially affect a firm will entail sharp predictable
effects. We will analyse the consequences of this potential risk on perpetual
American derivatives, a topic connected with a wide class of recurrent problems
in physics: holders of American options must look for the fair price and the
optimal exercise strategy at once, a typical question of free absorbing
boundaries. We present explicit solutions to the most common contract
specifications and derive analytical expressions concerning the mean and higher
moments of the exercise time.

categories: physics.soc-ph q-fin.PR q-fin.RM q-fin.ST


title: Solution to the twin image problem in holography

abstract:
  While the invention of holography by Dennis Gabor truly constitutes an
ingenious concept, it has ever since been troubled by the so called twin image
problem limiting the information that can be obtained from a holographic
record. Due to symmetry reasons there are always two images appearing in the
reconstruction process. Thus, the reconstructed object is obscured by its
unwanted out of focus twin image. Especially for emission electron as well as
for x- and gamma-ray holography, where the source-object distances are small,
the reconstructed images of atoms are very close to their twin images from
which they can hardly be distinguished. In some particular instances only,
experimental efforts could remove the twin images. More recently, numerical
methods to diminish the effect of the twin image have been proposed but are
limited to purely absorbing objects failing to account for phase shifts caused
by the object. Here we show a universal method to reconstruct a hologram
completely free of twin images disturbance while no assumptions about the
object need to be imposed. Both, amplitude and true phase distributions are
retrieved without distortion.


title: The system of uniformly accelerating observers

abstract:
  We begin with a scenario that involves point-like observers starting at t=0
from the origin O of an inertial reference frame. They move with all possible
proper accelerations in the positive direction of the OX axis. Equipped with
light sources the accelerating observers get involved in experiments like
Doppler Effect, radar detection and radar echo. We derive formulas accounting
for the experiments mentioned above. In the case of the Doppler Effect we take
into account the non-locality aspect in the time interval measurement by
accelerating observers.


title:
Creating a universe from thermodynamic thought experiments II --
  exploring a basis for structure and force

abstract:
  Assuming that the universe is a system obedient to known thermodynamic laws
and equations, here we explore whether it is a possibility for the universe to
exist and evolve without any cosmic structure or force necessarily emerging
within it. From symmetry considerations and the invariance of Boltzmann's
constant during the experiment, we infer that it is an inevitable occurrence
that structure and force will appear during transformation of the created
universe.


title: Structural Inference of Hierarchies in Networks

abstract:
  One property of networks that has received comparatively little attention is
hierarchy, i.e., the property of having vertices that cluster together in
groups, which then join to form groups of groups, and so forth, up through all
levels of organization in the network. Here, we give a precise definition of
hierarchical structure, give a generic model for generating arbitrary
hierarchical structure in a random graph, and describe a statistically
principled way to learn the set of hierarchical features that most plausibly
explain a particular real-world network. By applying this approach to two
example networks, we demonstrate its advantages for the interpretation of
network data, the annotation of graphs with edge, vertex and community
properties, and the generation of generic null models for further hypothesis
testing.


title:
Scaling Law for the Cosmological Constant from Quantum Cosmology with
  Seven Extra Dimensions

abstract:
  According to a model of quantum cosmology the maximum number of degrees of
freedom allowed in our three dimensions was determined by the size of seven
extra dimensions in an initial excited state before inflation. The size of the
extra dimensions can be inferred from a simple scheme for unifying the strong
force and gravity. Coupled with the Bekenstein-Hawking entropy bound, these
considerations lead to a scaling law for the cosmological constant that has
been proposed independently by several authors.


title:
Numerical investigations on the finite time singularity in
  two-dimensional Boussinesq equations

abstract:
  To investigate the finite time singularity in three-dimensional (3D) Euler
flows, the simplified model of 3D axisymmetric incompressible fluids (i.e.,
two-dimensional Boussinesq approximation equations) is studied numerically. The
system describes a cap-like hot zone of fluid rising from the bottom, while the
edges of the cap lag behind, forming eye-like vortices. The hot liquid is
driven by the buoyancy and meanwhile attracted by the vortices, which leads to
the singularity-forming mechanism in our simulation. In the previous 2D
Boussinesq simulations, the symmetricial initial data is used. However, it is
observed that the adoption of symmetry leads to coordinate singularity.
Moreover, as demonstrated in this work that the locations of peak values for
the vorticity and the temperature gradient becomes far apart as $t$ approaches
the predicted blow-up time. This suggests that the symmetry assumption may be
unreasonable for searching solution blow-ups. One of the main contributions of
this work is to propose an appropriate asymmetric initial condition, which
avoids coordinate singularity and also makes the blow-up to occur much earlier
than that given by the previously simulations. The shorter simulation time
suppresses the development of the round-off error. On the numerical side, the
pseudo-spectral method with filtering technique is adopted. The resolutions
adopted in this study vary from $1024^2$, $2048^2$, $4096^2$ to $6144^2$. With
our proposed asymmetric initial condition, it is shown that the $4096^2$ and
$6144^2$ runs yield convergent results when $t$ is fairly close to the
predicted blow-up time. Moreover, as expected the locations of peak values for
the vorticity and the temperature gradient are very close to each other as $t$
approaches the predicted blow-up time.


title:
Julian Schwinger: Nuclear Physics, the Radiation Laboratory,
  Renormalized QED, Source Theory, and Beyond

abstract:
  Julian Schwinger's influence on twentieth century science is profound and
pervasive. Of course, he is most famous for his renormalization theory of
quantum electrodynamics, for which he shared the Nobel Prize with Richard
Feynman and Sin-itiro Tomonaga. But although this triumph was undoubtedly his
most heroic work, his legacy lives on chiefly through subtle and elegant work
in classical electrodynamics, quantum variational principles, proper-time
methods, quantum anomalies, dynamical mass generation, partial symmetry, and
more. Starting as just a boy, he rapidly became the pre-eminent nuclear
physicist in the late 1930s, led the theoretical development of radar
technology at MIT during World War II, and then, soon after the war, conquered
quantum electrodynamics, and became the leading quantum field theorist for two
decades, before taking a more iconoclastic route during his last quarter
century.


title:
Magnetic structure of free cobalt clusters studied with Stern-Gerlach
  deflection experiments

abstract:
  We have studied the magnetic properties of free cobalt clusters in two
semi-independent Stern-Gerlach deflection experiments at temperatures between
60 and 307 K. We find that clusters consisting of 13 to 200 cobalt atoms
exhibit behavior that is entirely consistent with superparamagnetism, though
complicated by finite-system fluctuations in cluster temperature. By fitting
the data to the Langevin function, we report magnetic moments per atom for each
cobalt cluster size and compare the results of our two measurements and all
those performed previously. In addition to a gradual decrease in moment per
atom with increasing size, there are oscillations that appear to be caused by
geometrical shell structure. We discuss our observations in light of the two
competing models for Langevin-like magnetization behavior in free clusters,
superparamagnetism and adiabatic magnetization, and conclude that the evidence
strongly supports the superparamagnetic model.


title:
Quantum number dimensional scaling analysis for excited states of
  multielectron atoms

abstract:
  A new dimensional scaling method for the calculation of excited states of
multielectron atoms is introduced. By including the principle and orbital
quantum numbers in the dimension parameter, we obtain an energy expression for
excited states including high angular momentum states. The method is tested on
He, Li, and Be. We obtain good agreement with more orthodox quantum mechanical
treatments even in the zeroth order.


title:
The Taylor Interpolation through FFT Algorithm for Electromagnetic Wave
  Propagation and Scattering

abstract:
  The Taylor Interpolation through FFT (TI-FFT) algorithm for the computation
of the electromagnetic wave propagation in the quasi-planar geometry within the
half-space is proposed in this article. There are two types of TI-FFT
algorithm, i.e., the spatial TI-FFT and the spectral TI-FFT. The former works
in the spatial domain and the latter works in the spectral domain. It has been
shown that the optimized computational complexity is the same for both types of
TI-FFT algorithm, which is N_r^{opt} N_o^{opt} O (N log_2 N) for an N = N_x
\times N_y computational grid, where N_r^{opt} is the optimized number of
slicing reference planes and N_o^{opt} is the optimized order of Taylor series.
Detailed analysis shows that N_o^{opt} is closely related to the algorithm's
computational accuracy \gamma_{TI}, which is given as N_o^{opt} ~ -
ln(\gamma_{TI}) and the optimized spatial slicing spacing between two adjacent
spatial reference planes \delta_z^{opt} only depends on the characteristic
wavelength \lambda_c of the electromagnetic wave, which is given as
\delta_z^{opt} ~ 1/17 \lambda_c. The planar TI-FFT algorithm allows a large
sampling spacing required by the sampling theorem. What's more, the algorithm
is free of singularities and it works particularly well for the narrow-band
beam and the quasi-planar geometry.


title:
Observation of multiple ionization pathways for OCS in an intense laser
  field resolved by three-dimensional covariance mapping and visualized by
  hierarchical ionization topology

abstract:
  The two- and three-body Coulomb explosion of carbonyl sulfide (OCS) by 790
nm, 50 fs laser pulses focussed to $\approx $ 10$^{16}$ Wcm$^{-2}$ has been
investigated by three-dimensional covariance mapping technique. For the first
time in a triatomic molecule, a single charge state, in this case the
trication, has been observed to dissociate into two distinct energy channels.
With the aid of a three dimensional visualization technique to reveal the
ionization hierarchy, evidence is presented for the existence of two sets of
ionization pathways resulting from these two initial states. While one group of
ions can be modeled using a Classical enhanced ionization model, the second
group, consisting of mainly asymmetric channels, can not. The results provide
clear evidence that an enhanced ionization approach must also be accompanied by
an appreciation of the effects of excited ionic states and multi-electronic
processes.


title: Triple-GEM performance in He-based mixtures

abstract:
  The performance of triple-GEM detectors in He+N2 gas mixtures is studied in
the range of 1-10 atm. The results obtained are relevant in the field of
minimization of ionic space-charge effect in the TPC and neutron detection.


title: Is the Fermi field contact and isotropic?

abstract:
  It is shown that the contribution to the induction which at an internal point
of a spin density distribution is mathematically described as a local is
virtually caused by the summing-up of the fields created by all elements of
this distribution. Therefore, the proportionality coefficient between this
contact (Fermi) field and magnetic moment density at the point of observation
is equal to 8pi/3 only for spherically symmetrical s-shells. If the symmetry of
spin density distribution lowers, the value of this coefficient becomes
dependent on the spin direction. As a sequence, in low-symmetry crystals and
molecules additional anisotropic contributions to the hyperfine field emerge.


title:
Direct and absolute temperature mapping and heat transfer measurements
  in diode-end-pumped Yb:YAG

abstract:
  We report direct and absolute temperature measurements in a diode-end-pumped
Yb:YAG crystal, using a calibrated infrared camera, with a 60-$\mu$m spatial
resolution. The heat transfer coefficient has been measured, for the first time
to our knowledge, with four different types of thermal contact (H = 0.25, 0.28,
0.9 and 2.0 for bare contact, graphite layer, indium foil and heat sink grease
respectively). The dynamics of thermal effects is also presented.


title: Graduate Program in Astrophysics in Split

abstract:
  Beginning in autumn 2008 the first generation of astronomy master students
will start a 2 year course in Astrophysics offered by the Physics department of
the University of Split, Croatia
(http://fizika.pmfst.hr/astro/english/index.html). This unique master course in
South-Eastern Europe, following the Bologna convention and given by astronomers
from international institutions, offers a series of comprehensive lectures
designed to greatly enhance students' knowledge and skills in astrophysics, and
prepare them for a scientific career. An equally important aim of the course is
to recognise the areas in which astronomy and astrophysics can serve as a
national asset and to use them to prepare young people for real life
challenges, enabling graduates to enter the modern society as a skilled and
attractive work-force. In this contribution, I present an example of a
successful organisation of international astrophysics studies in a developing
country, which aims to become a leading graduate program in astrophysics in the
broader region. I will focus on the benefits of the project showing why and in
what way astronomy can be interesting for third world countries, what are the
benefits for the individual students, nation and region, but also research,
science and the astronomical community in general.


title:
Passively mode-locked diode-pumped Nd:YVO4 oscillator operating at
  ultra-low repetition rate

abstract:
  We demonstrate the operation of an ultra low repetition rate, high peak
power, picosecond diode pumped Nd:YVO4 passively mode locked laser oscillator.
Repetition rates even below 1 MHz were achieved with the use of a new design
multiple-pass cavity and a semiconductor saturable absorber. Long term stable
operation at 1.2 MHz, pulse duration of 16.3 ps and average output power of 470
mW corresponding to 24 KW peak power pulses is reported. This is, to our
knowledge, the lowest repetition rate high peak power pulses ever generated
directly from a picosecond laser resonator without cavity dumping.


title:
The flow generated by an active olfactory system of the red swamp
  crayfish

abstract:
  Crayfish are nocturnal animals that mainly rely on their chemoreceptors to
locate food. On a crayfish scale chemical stimuli received from a distant
source are dispersed by an ambient flow rather than molecular diffusion. When
the flow is weak or absent, food search can be facilitated by currents
generated by the animal itself. Crayfish employ their anterior fan organs to
produce a variety of flow patterns. Here we study the flow generated by
Procambarus clarkii in response to odour stimulation. We found that while
searching for food the crayfish generates one or two outward jets. These jets
create an inflow which draws odour to the crayfish's anterior chemoreceptors.
We quantified velocity fields in the inflow region using Particle Image
Velocimetry. The results show that the inflow velocity decreases proportionally
to the inverse distance from the animal so that it takes about a minute for an
odour plume to reach the animal's chemoreceptors from a distance of 10 cm. We
compare the inflow generated by live crayfish with that produced by a mimicking
device, a phantom. The phantom consisted of two nozzles and an inlet providing
two jets and a sink so that the overall mass flux was zero. The use of a
phantom enabled us to analyze the inflow at various jet parameters. We showed
that variation of the jets' directions and relative intensities allows changing
the direction of odour attraction. These results provide a rationale for
biomimetic robot design. We discuss sensitivity and efficiency of such a robot.


title:
Relativistic velocity addition and the relativity of space and time
  intervals

abstract:
  A thought experiment first proposed by Sartori is analysed using the parallel
velocity addition formula of special relativity. The distances and proper-time
intervals between some similarly defined spatial coincidence events are found
to be widely different in different inertial frames. This relativity of space
and time intervals is quite distinct from the well-known time-dilatation and
length contraction effects of special relativity. Sartori's claimed derivation
of the parallel velocity addition formula, assuming relativistic time
dilatation, based on the thought experiment, is shown to be fortuitous.


title: Fast Photon Detection for Particle Identification with COMPASS RICH-1

abstract:
  Particle identification at high rates is an important challenge for many
current and future high-energy physics experiments. The upgrade of the COMPASS
RICH-1 detector requires a new technique for Cherenkov photon detection at
count rates of several $10^6$ per channel in the central detector region, and a
read-out system allowing for trigger rates of up to 100 kHz. To cope with these
requirements, the photon detectors in the central region have been replaced
with the detection system described in this paper. In the peripheral regions,
the existing multi-wire proportional chambers with CsI photocathode are now
read out via a new system employing APV pre-amplifiers and flash ADC chips. The
new detection system consists of multi-anode photomultiplier tubes (MAPMT) and
fast read-out electronics based on the MAD4 discriminator and the F1-TDC chip.
The RICH-1 is in operation in its upgraded version for the 2006 CERN SPS run.
We present the photon detection design, constructive aspects and the first
Cherenkov light in the detector.


title: Relativity and Aether Theory, a Crucial Distinction

abstract:
  We study the case of two rockets which meet at a point O of an inertial
co-ordinate system S, and are scheduled to move at constant speed, in opposite
directions, toward two targets placed at equal distances from point O. At the
instant they meet, the clocks inside the rockets are set to zero. When they
reach the targets the rockets meet two clocks A and B whose reading is
identical. This question which was tackled in ref [1] is studied here in depth.
Assuming the existence of a preferred aether frame So in which the one-way
speed of light is isotropic, and the anisotropy of this speed in the other
frames, we show that, if the equal reading of the clocks A and B results from
an exact synchronization, the clocks inside the rockets will display different
readings when they reach A and B in contradiction with the relativity
principle. Conversely, if the clocks A and B, which display an equal reading,
have been synchronized by means of the Einstein-Poincare procedure, the inboard
clocks will also display the same reading, a fact which seems in agreement with
the relativity principle. But this synchronization method presupposes the
invariance of the one-way speed of light, in contradiction with the assumptions
made, and, therefore, introduces a measurement error. This demonstrates that if
we assume the existence of an aether frame, the apparent relativity principle
is not a fundamental principle; it depends on an arbitrary synchronization. In
any case, this is an example of an experimental measurement which can be
explained by aether theory without the assumption of the invariance of the
one-way speed of light in all inertial frames.


title:
Electromagnetic forces for an arbitrary optical trapping of a spherical
  dielectric

abstract:
  Analytical solution for optical trapping force on a spherical dielectric
particle for an arbitrary positioned focused beam is presented in a generalized
Lorenz-Mie and vectorial diffraction theory. In this case the exact
electromagnetic field is considered in the focal region. A double tweezers
setup was employed to perform ultra sensitive force spectroscopy and observe
the forces, demonstrating the selectively couple of the transverse electric
(TE), transverse magnetic (TM) modes by means of the beam polarization and
positioning, and to observe correspondent morphology-dependent resonances (MDR)
as a change in the optical force. The theoretical prediction of the theory
agrees well with the experimental results. The algorithm presented here can be
easily extended to other beam geometries and scattering particles.


title: New 3D multipass amplifier based on Nd:YAG or Nd:YVO4 crystals

abstract:
  We report on new simple and efficient multipass amplifiers using prisms or
corner cubes to perform several passes in different planes of incidence. This
scheme provides an optimized overlap between the signal passes and the pumped
volume. We investigated our amplification geometry with Nd:YAG and Nd: YVO4
crystals : the use of a low doped (0.3%) Nd:YVO4 crystal allowed better thermal
behaviour and higher performances. We amplified a pulsed microlaser (110 mW of
average power at 1064 nm) and obtained a diffraction-limited output beam with
an average power of 5.7 W for 15 W of pump power and a small-signal gain of 56
dB in a 6-pass configuration.


title: Numerical analysis of frazil ice formation in turbulent convection

abstract:
  We study the first steps of ice formation in fresh water turbulent convection
(frazil ice regime). We explore the sensitivity of the ice formation process to
the set of non-dimensional parameters governing the system. We model the
mixture of ice crystals and water as a two-phase medium composed of water and
ice particles of fixed diameter. We use the Boussinesq approximation and we
integrate numerically the set of equation making use of a numerical code based
on second order finite difference. A dynamic LES model for the subgrid scales
is used. We show that the ice particle rise velocity and the ice concentration
source term coefficient significantly affect the frazil ice dynamics. The
maximum of ice production is obtained in those situations where the rise
velocity is of the same order of magnitude of a characteristic velocity of the
thermal downwelling plumes. We develop a simple model which captures the trend
of the growth rate as a function of the relevant parameters. Finally, we
explore the nonlinear regime and we show that the parameter which plays a key
role in fixing the concentration value at the statistically steady state is the
heat exchange source term coefficient.


title: Negative refraction from quasi-planar chiral inclusions

abstract:
  This letter proposes a quasi-planar chiral resonator suitable for the design
of negative refractive index matamaterial. It is presented an analytical model
for the determination of its polarizabilities, and the viability of negative
refraction in chiral and racemic arrangements with the proposed inclusions is
analyzed. The present analysis is expected to pave the way to the design of
negative refractive index matamaterials made of a single kind of inclusions
feasible from standard photo-etching techniques.


title:
Picosecond laser source at 1 MHz with continuous tunability in the
  visible red band

abstract:
  We report the first demonstration to our knowledge of a continuously tunable
picosecond laser operating around 1 MHz. The emission can be tuned from 640 to
685 nm and the repetition rate from 200 kHz to 1 MHz with a pulse duration of
less than 200 ps. The system is based on a Nd:YVO4 passively Q-switched
microchip laser providing a few tens of nJ per pulse. Two cascaded stages of
amplification are then used to increase the pulse energy to several microJ .
The frequency doubled radiation is then used to pump a
periodically-poled-niobate-lithium (PPLN)-based optical parametric generator in
an all-solid-state architecture. 20 nJ of tunable signal radiation are
obtained. We also demonstrated 300-ps pulses generation in the UV (355 nm) at 1
MHz.


title:
Theory of electrically controlled exhibition of circular Bragg
  phenomenon by an obliquely excited structurally chiral material

abstract:
  The boundary-value problem of the reflection and transmission of a plane wave
due to a slab of an electro-optic structurally chiral material (SCM) is
formulated in terms of a 4x4 matrix ordinary differential equation. The SCM
slab can be locally endowed with one of 20 classes of point group symmetry, and
is subjected to a dc voltage across its thickness. The enhancement (and, in
some cases, the production) of the circular Bragg phenomenon (CBP) by the
application of the dc voltage has either switching or
circular-polarization-rejection applications in optics. The twin possibilities
of thinner filters and electrical manipulation of the CBP, depending on the
local crystallographic class as well as the constitutive parameters of the SCM,
emerge.


title: Nonlinear Optical Spectroscopy of Excited States in Polyfluorene

abstract:
  We used a variety of nonlinear optical (NLO) spectroscopies to study the
singlet excited states order, and primary photoexcitations in polyfluorene; an
important blue emitting p-conjugated polymer. The polarized NLO spectroscopies
include ultrafast pump-probe photomodulation, two-photon absorption, and
electroabsorption. For completeness we also measured the linear absorption and
photoluminescence spectra. We found that the primary photoexcitations in
polyfluorene are singlet excitons.


title:
Gravity Control produced by a Thermoionic Current through the Air at
  Very Low Pressure

abstract:
  It was observed that samples hung above a thermoionic current exhibit a
weight decrease directly proportional to the intensity of the current. The
observed phenomenon appears to be absolutely new and unprecedented in the
literature and can not be understood in the framework of the general
relativity. It is pointed out the possibility that this unexpected effect is
connected with a possible correlation between gravity and electromagnetism.


title:
A New Light-Speed Anisotropy Experiment: Absolute Motion and
  Gravitational Waves Detected

abstract:
  Data from a new experiment measuring the anisotropy of the one-way speed of
EM waves in a coaxial cable, gives the speed of light as 300,000+/-400+/-20km/s
in a measured direction RA=5.5+/-2hrs, Dec=70+/-10deg S, is shown to be in
excellent agreement with the results from seven previous anisotropy
experiments, particularly those of Miller (1925/26), and even those of
Michelson and Morley (1887). The Miller gas-mode interferometer results, and
those from the RF coaxial cable experiments of Torr and Kolen (1983), De Witte
(1991) and the new experiment all reveal the presence of gravitational waves,
as indicated by the last +/- variations above, but of a kind different from
those supposedly predicted by General Relativity. The understanding of the
operation of the Michelson interferometer in gas-mode was only achieved in 2002
and involved a calibration for the interferometer that necessarily involved
Special Relativity effects and the refractive index of the gas in the light
paths. The results demonstrate the reality of the Fitzgerald-Lorentz
contraction as an observer independent relativistic effect. A common
misunderstanding is that the anisotropy of the speed of light is necessarily in
conflict with Special Relativity and Lorentz symmetry - this is explained. All
eight experiments and theory show that we have both anisotropy of the speed of
light and relativistic effects, and that a dynamical 3-space exists - that
absolute motion through that space has been repeatedly observed since 1887.
These developments completely change fundamental physics and our understanding
of reality.


title: Experimental study of pedestrian flow through a bottleneck

abstract:
  In this work the results of a bottleneck experiment with pedestrians are
presented in the form of total times, fluxes, specific fluxes, and time gaps. A
main aim was to find the dependence of these values from the bottleneck width.
The results show a linear decline of the specific flux with increasing width as
long as only one person at a time can pass, and a constant value for larger
bottleneck widths. Differences between small (one person at a time) and wide
bottlenecks (two persons at a time) were also found in the distribution of time
gaps.


title:
Tunable plasma wave resonant detection of optical beating in high
  electron mobility transistor

abstract:
  We report on tunable terahertz resonant detection of two 1.55 µm
cw-lasers beating by plasma waves in AlGaAs/InGaAs/InP high-electron-mobility
transistor. We show that the fundamental plasma resonant frequency and its odd
harmonics can be tuned with the applied gate-voltage in the range 75-490 GHz.
The observed frequency dependence on gate-bias is found to be in good agreement
with the theoretical plasma waves dispersion law.


title:
Ab initio potential energy surfaces, bound states and electronic
  spectrum of the Ar-SH complex

abstract:
  New ab initio potential energy surfaces for the doublet pi ground electronic
state of the Ar-SH complex are presented, calculated at the
RCCSD(T)/aug-cc-pV5Z level. Weakly bound rotation-vibration levels are
calculated using coupled-channel methods that properly account for the coupling
between the two electronic states. The resulting wavefunctions are analysed and
a new adiabatic approximation including spin-orbit coupling is proposed. The
ground-state wavefunctions are combined with those obtained for the excited
doublet sigma + state [Phys. Chem. Chem. Phys. 6, 5463 (2004)] to produce
transition dipole moments. Modelling the transition intensities as a
combination of these dipole moments and calculated lifetime values [J. Chem.
Phys. 109, 170 (1998)] leads to a good representation of the experimental
fluorescence excitation spectrum [J. Chem. Phys. 98, 4301 (1993)].


title:
Time and position distributions in large volume spherical scintillation
  detectors

abstract:
  Large spherical scintillation detectors are playing an increasingly important
role in experimental neutrino physics studies. From the instrumental point of
view the primary signal response of these set-ups is constituted by the time
and amplitude of the anode pulses delivered by each individual phototube
following a particle interaction in the scintillator. In this work, under some
approximate assumptions, we derive a number of analytical formulas able to give
a fairly accurate description of the most important timing features of these
detectors, intended to complement the more complete Monte Carlo studies
normally used for a full modelling approach. The paper is completed with a
mathematical description of the event position distributions which can be
inferred, through some inference algorithm, starting from the primary time
measures of the photomultiplier tubes.


title: High-Order Correlation Functions of Binary Multi-Step Markov Chains

abstract:
  Two approaches to studying the correlation functions of the binary Markov
sequences are considered. The first of them is based on the study of
probability of occurring different ''words'' in the sequence. The other one
uses recurrence relations for correlation functions. These methods are applied
for two important particular classes of the Markov chains. These classes
include the Markov chains with permutative conditional probability functions
and the additive Markov chains with the small memory functions. The exciting
property of the self-similarity (discovered in Phys. Rev. Lett. 90, 110601
(2003) for the additive Markov chain with the step-wise memory function) is
proved to be the intrinsic property of any permutative Markov chain.
Applicability of the correlation functions of the additive Markov chains with
the small memory functions to calculating the thermodynamic characteristics of
the classical Ising spin chain with long-range interaction is discussed.


title: Three Important Theorems for Fluid Dynamics

abstract:
  The new proposed "energy gradient theory," which physically explains the
phenomena of flow instability and turbulent transition in shear flows and has
been shown to be valid for parallel flows, is extended to curved flows in this
study. Then, three important theorems for fluid dynamics are deduced. These
theorems are (1) Potential flow (inviscid and irrotational) is stable. (2)
Inviscid rotational (nonzero vorticity) flow is unstable. (3) Velocity profile
with an inflectional point is unstable when there is no work input or output to
the system, for both inviscid and viscous flows. These theorems are, for the
first time, deduced, and are of great significance for the understanding of
generation of turbulence and the explanation of complex flows.
  From these results, it is concluded that the classical Rayleigh theorem
(1880) on inflectional velocity instability of inviscid flows is incorrect
which has last for more than a century. It is demonstrated that existence of
inflection point on velocity profile is a sufficient condition, but not a
necessary condition for flow instability, for both inviscid and viscous flows.
The paradox of dual role of viscosity has been resolved: viscosity has only
stable role. Why the paradox appeared is due to that the Rayleigh Theorem of
inviscid flows by linear analysis is incorrect.


title:
Longitudinal dynamics with RF phase modulation in the LNLS electron
  storage ring

abstract:
  In the Brazilian synchrotron light source, we observed that modulating the
phase of the accelerating fields at approximately twice the synchrotron
frequency suppressed remarkably well a longitudinal coupled-bunch mode of the
beam driven by a higher order mode (HOM) in one of the radiofrequency (RF)
cavities. In this work, we present the results of a set of systematic
measurements, in single and multibunch mode, aimed at characterizing the
effects of RF phase modulation on the beam. We compare those experiments with
the results of tracking simulations and of a theoretical model in which Landau
damping is the stabilizing mechanism that explains the suppression of the
longitudinal coupled bunch instability. We also measure the frequency of the
stable islands created in longitudinal phase space by phase modulation and the
longitudinal beam transfer function (BTF) as a function of the modulation
frequency and amplitude. The experimental results are in good agreement with
theoretical expectations.


title: The Adiabatic Invariance of the Action Variable in Classical Dynamics

abstract:
  We consider one-dimensional classical time-dependent Hamiltonian systems with
quasi-periodic orbits. It is well-known that such systems possess an adiabatic
invariant which coincides with the action variable of the Hamiltonian
formalism. We present a new proof of the adiabatic invariance of this quantity
and illustrate our arguments by means of explicit calculations for the harmonic
oscillator.
  The new proof makes essential use of the Hamiltonian formalism. The key step
is the introduction of a slowly-varying quantity closely related to the action
variable. This new quantity arises naturally within the Hamiltonian framework
as follows: a canonical transformation is first performed to convert the system
to action-angle coordinates; then the new quantity is constructed as an action
integral (effectively a new action variable) using the new coordinates. The
integration required for this construction provides, in a natural way, the
averaging procedure introduced in other proofs, though here it is an average in
phase space rather than over time.


title:
Comment on "Radial dependence of radiation from a bounded source" by
  Kirk T. McDonald

abstract:
  The purpose of this note is to point out that McDonald's criticism of our
work \cite{r1} is based on a circular argument. In order to show that the field
of a bounded source falls off as $f(\theta,\phi)/r$ in the far zone, McDonald
uses a Huygens-Kirchhoff diffraction integral whose derivation (from Maxwell's
equations) already entails assuming a fall-off of this form for the field at
infinity \cite{r2}. ($r$, $\theta$ and $\phi$ are the spherical polar
coordinates centred on a point within the source, and $f$ is a factor
independent of $r$.


title: Heat to electricity thermoacoustic-magnetohydrodynamic conversion

abstract:
  In this work, a new concept for the conversion of heat into electricity is
presented. The conversion is based on the combined effects of a thermoacoustic
prime mover coupled with a magnetohydrodynamic generator, using different
working fluids in each process. The results of preliminary experiments are also
presented.


title: Measurement of refractive index of single microparticles

abstract:
  The refractive index of single microparticles is derived from precise
measurement and rigorous modeling of the stiffness of a laser trap. We
demonstrate the method for particles of four different materials with diameters
from 1.6 to 5.2 microns and achieve an accuracy of better than 1%. The method
greatly contributes as a new characterization technique because it works best
under conditions (small particle size, polydispersion) where other methods,
such as absorption spectroscopy, start to fail. Particles need not be
transferred to a particular fluid, which prevents particle degradation or
alteration common in index matching techniques. Our results also show that
advanced modeling of laser traps accurately reproduces experimental reality.


title: On non existence of tokamak equilibria with purely poloidal flow

abstract:
  It is proved that irrespective of compressibility tokamak steady states with
purely poloidal mass flow can not exist in the framework of either
magnetohydrodynamics (MHD) or Hall MHD models. Non-existence persists within
single fluid plasma models with pressure anisotropy and incompressible flows.


title: Recognition of paper samples by correlation of their speckle patterns

abstract:
  Buchanan et al. [Nature 436, p. 475 (2005)] have shown that it is possible to
recognize paper samples via their speckle pattern by using a line-shaped laser
focus, four photo detectors and a scanning mechanism. In this report
recognition of five out of ten paper samples is presented. The sample was
illuminated by a 2.62 +- 0.02 mm circular spot and the reflected light was
measured by a static CCD. We have formulated a criterion for recognition that
limits the probability of false recognition to 0.1 % for the experiment with
ten samples. We obtained results that show that the probability of false
recognition will be negligible for a large amount of samples. The properties of
speckle originating from a line and a spot illumination source have been
compared to see whether the use of a line results in major advantages for the
recognition of samples.


title: Field Emission Dark Current of Technical Metallic Electrodes

abstract:
  In the framework of the Low Emittance Gun (LEG) project, high gradient
acceleration of a low emittance electron beam will be necessary. In order to
achieve this acceleration a -500 kV, 250 ns FWHM, pulse will be applied in
between two electrodes. Those electrodes should sustain the pulsed field
without arcing, must not outgass and must not emit electrons. Ion back
bombardment, and dark current will be damageable to the electron source as well
as for the low emittance beam. Electrodes of commercially available OFE copper,
aluminium, stainless steel, titanium and molybdenum were tested following
different procedures including plasma glow discharge cleaning.


title:
Single photonics at telecom wavelengths using nanowire superconducting
  detectors

abstract:
  Single photonic applications - such as quantum key distribution - rely on the
transmission of single photons, and require the ultimate sensitivity that an
optical detector can achieve. Single-photon detectors must convert the energy
of an optical pulse containing a single photon into a measurable electrical
signal. We report on fiber-coupled superconducting single-photon detectors
(SSPDs) with specifications that exceed those of avalanche photodiodes (APDs),
operating at telecommunication wavelength, in sensitivity, temporal resolution
and repetition frequency. The improved performance is demonstrated by measuring
the intensity correlation function g(2)(t) of single-photon states at 1300nm
produced by single semiconductor quantum dots (QDs).


title: Compound Pendulum to Monitor Hurricanes and Tropical Storms

abstract:
  The period of an undamped compound pendulum has been selected to maximize the
instrument's response to microseisms, when functioning as a type of horizontal
seismometer. When functioning as a tiltmeter, the instrument is also capable of
monitoring eigenmode oscillations of the Earth. Other instruments designed by
the author, some of which were monitored during hurricanes, suggest that storm
seismicity in the frequency range of this pendulum could aid the process of
hurricane forecasting.


title:
A Possible Biogenic Origin for Hydrogen Peroxide on Mars: The Viking
  Results Reinterpreted

abstract:
  The adaptability of extremophiles on Earth raises the question of what
strategies putative life might have used to adapt to the present conditions on
Mars. Here, we hypothesize that organisms might utilize a water-hydrogen
peroxide (H2O-H2O2) mixture rather than water as an intracellular liquid. This
adaptation would have the particular advantages in the martian environment of
providing a low freezing point, a source of oxygen, and hygroscopicity. The
findings by the Viking experiments are reinterpreted in the light of this
hypothesis. Our conclusion is that the hitherto mysterious oxidant in the
martian soil, which evolves oxygen when humidified, might be H2O2 of biological
origin. This interpretation has consequences for site selection for future
missions to search for life on Mars.


title: On a complementary scale of crystal-field strength

abstract:
  A new measure of the crystal-field strength, complementary to the
conventional one, is defined. It is based on the rotational invariants
|B_{k0}|_{av} or |\sum_{k}B_{k0}|_{av}, k=2,4,6, of the crystal-(ligand)-field
(CF) Hamiltonian H_{CF} parametrizations, i.e. on the axial CF parameters
modules averaged over all reference frame orientations. They turn out to be
equal to |H_{CF}^{(k)}|_{av} and |H_{CF}|_{av}, respectively. While the
traditional measure is established on the parametrization modules or on the
second moment of the CF energy levels, the introduced scale employs rather the
first moment of the energy modules and has better resolving power. The new
scale is able to differentiate the strength of various iso-modular
parametrizations according to the classes of rotationally equivalent
parametrizations. Using both the compatible CF strength measures one may draw
more accurate conclusions about the Stark levels arrays and particularly their
total splitting magnitudes.


title: A Note on Aryabhata's Principle of Relativity

abstract:
  This paper presents the principle of relativity of motion as described in
Aryabhata's text Aryabhatiya. This principle is likely to have been
instrumental in the faming of Aryabhata's theory that the earth rotated on its
axis and, therefore, it has played a very important role in the history of
astronomy.


title: Optical atomic coherence at the one-second time scale

abstract:
  Highest resolution laser spectroscopy has generally been limited to single
trapped ion systems due to rapid decoherence which plagues neutral atom
ensembles. Here, precision spectroscopy of ultracold neutral atoms confined in
a trapping potential shows superior optical coherence without any deleterious
effects from motional degrees of freedom, revealing optical resonance
linewidths at the hertz level with an excellent signal to noise ratio. The
resonance quality factor of 2.4 x 10^{14} is the highest ever recovered in any
form of coherent spectroscopy. The spectral resolution permits direct
observation of the breaking of nuclear spin degeneracy for the 1S0 and 3P0
optical clock states of 87Sr under a small magnetic bias field. This optical
NMR-like approach allows an accurate measurement of the differential Lande
g-factor between the two states. The optical atomic coherence demonstrated for
collective excitation of a large number of atoms will have a strong impact on
quantum measurement and precision frequency metrology.


title: One Approach on Derivation of the Schrodinger Equation of Free Particle

abstract:
  The Schrodinger equation based on the de Broglie wave is the most fundamental
equation of the quantum mechanics. There can be no doubt about it's prediction
validity. However, the probabilistic interpretation on the quantum mechanics
has insoluble semantic interpretations like reduction of wave packet on
observations of physical values. Especially, it is not clear that the wave
function which is described by complex function, is whether formality or
reality to express the state of particle motion. On this paper, we interpret
the wave nature of particle as not the inherency of particle itself, but the
motional property of particle in fluctuated space-time due to the kinetic
energy and momentum the belief that the kinetic energy and momentum fluctuates
the microscopic space-time, and the particle move through the fluctuated
space-time adversely. Then, through the particle motion in the Euclidean
space-time, the particle will be recognized as if it has the wave nature. We
estimate the governing equation of fluctuations of microscopic space-time based
on the macroscopic law of motion. On this paper, the equivalence between the
governing equation and the Schrodinger equation is indicated.


title:
Dynamic cancellation of ac Stark shift for pulsed EIT/Raman optical
  lattice clocks

abstract:
  We propose a combination of Electromagnetically Induced Transparency
(EIT)/Raman and pulsed spectroscopy techniques to accurately cancel frequency
shifts arising from EIT fields in forbidden optical lattice clock transitions
of alkaline earth atoms. Time-separated laser pulses are designed to trap atoms
in coherent superpositions while eliminating off-resonance ac Stark
contributions at particular laser detunings from the intermediate excited
state. The scheme achieves efficient population transfer up to 60% with
potential inaccuracy $<$ $10^{-17}$. Cancellation of external light shifts
determined by a density matrix approach is confirmed by a complex wave-function
formalism, sufficient at the mHz accuracy, under low field strengths or short
interaction times.


title: Light Computing

abstract:
  A configuration of light pulses is generated, together with emitters and
receptors, that allows computing. The computing is extraordinarily high in
number of flops per second, exceeding the capability of a quantum computer for
a given size and coherence region. The emitters and receptors are based on the
quantum diode, which can emit and detect individual photons with high accuracy.


title: Observation of Long-Lived Muonic Hydrogen in the 2S State

abstract:
  The kinetic energy distribution of ground state muonic hydrogen atoms
mu-p(1S) is determined from time-of-flight spectra measured at 4, 16, and 64
hPa H2 room-temperature gas. A 0.9 keV-component is discovered and attributed
to radiationless deexcitation of long-lived mu-p(2S) atoms in collisions with
H2 molecules. The analysis reveals a relative population of about 1%, and a
pressure-dependent lifetime (e.g. (30.4 +21.4 -9.7) ns at 64 hPa) of the
long-lived mu-p(2S) population, equivalent to a 2S-quench rate in mu-p(2S) + H2
collisions of (4.4 +2.1 -1.8) 10^11 s^-1 at liquid hydrogen density.


title: Blow Ups of Complex Solutions of the 3D-Navier-Stokes System

abstract:
  We consider complex-valued solutions of the three-dimensional Navier-Stokes
system without external forcing on $R^3$. We show that there exists an open set
in the space of 10-parameter families of initial conditions such that for each
family from this set there are values of parameters for which the solution
develops blow up in finite time.


title: Why wave-based classical communicators can never be totally secure?

abstract:
  Recently, we proposed a classical communicator which was inspired by the
Kirchhoff-loop-Johnson-like-Noise (KLJN) communicator and was claimed totally
secure. Here we withdraw this claim and prove that, similarly to earlier
intuitive suspicions, a wave-based classical communicator can never be totally
secure.


title:
Self-similar asymptotics for a class of Hele-Shaw flows driven solely by
  surface tension

abstract:
  We investigate the dynamics of relaxation, by surface tension, of a family of
curved interfaces between an inviscid and viscous fluids in a Hele-Shaw cell.
At t=0 the interface is assumed to be of the form |y|=A x^m, where A>0, m \geq
0, and x>0. The case of 0<m<1 corresponds to a smooth shape, m>1 corresponds to
a cusp, whereas m=1 corresponds to a wedge. The inviscid fluid tip retreats in
the process of relaxation, forming a lobe which size grows with time. Combining
analytical and numerical methods we find that, for any m, the relaxation
dynamics exhibit self-similar behavior. For m\neq 1 this behavior arises as an
intermediate asymptotics: at late times for 0\leq m<1, and at early times for
m>1. In both cases the retreat distance and the lobe size exhibit power law
behaviors in time with different dynamic exponents, uniquely determined by the
value of m. In the special case of m=1 (the wedge) the similarity is exact and
holds for the whole interface at all times t>0, while the two dynamic exponents
merge to become 1/3. Surprisingly, when m\neq 1, the interface shape, rescaled
to the local maximum elevation of the interface, turns out to be universal
(that is, independent of m) in the similarity region. Even more remarkably, the
same rescaled interface shape emerges in the case of m=1 in the limit of zero
wedge angle.


title: Structure and tie strengths in mobile communication networks

abstract:
  Electronic databases, from phone to emails logs, currently provide detailed
records of human communication patterns, offering novel avenues to map and
explore the structure of social and communication networks. Here we examine the
communication patterns of millions of mobile phone users, allowing us to
simultaneously study the local and the global structure of a society-wide
communication network. We observe a coupling between interaction strengths and
the network's local structure, with the counterintuitive consequence that
social networks are robust to the removal of the strong ties, but fall apart
following a phase transition if the weak ties are removed. We show that this
coupling significantly slows the diffusion process, resulting in dynamic
trapping of information in communities, and find that when it comes to
information diffusion, weak and strong ties are both simultaneously
ineffective.


title: Efficient Photonic Crystal Cavity-Waveguide Couplers

abstract:
  Coupling of photonic crystal (PC) linear three-hole defect cavities (L3) to
PC waveguides is theoretically and experimentally investigated. The systems are
designed to increase the overlap between the evanescent cavity field and the
waveguide mode, and to operate in the linear dispersion region of the
waveguide. Our simulations indicate increased coupling when the cavity is
tilted by 60 degrees with respect to the waveguide axis, which we have also
confirmed by experiments. We obtained up to 90% coupling efficiency into the
waveguide.


title:
On exact solutions and numerics for cold, shallow, and thermocoupled ice
  sheets

abstract:
  This three section report can be regarded as an extended appendix to (Bueler,
Brown, and Lingle 2006). First we give the detailed construction of an exact
solution to a standard continuum model of a cold, shallow, and thermocoupled
ice sheet. The construction is by calculation of compensatory accumulation and
heat source functions which make a chosen pair of functions for thickness and
temperature into exact solutions of the coupled system. The solution we
construct here is ``TestG'' in (Bueler and others, 2006) and the steady state
solution ``Test F'' is a special case. In the second section we give a
reference C implementation of these exact solutions. In the last section we
give an error analysis of a finite difference scheme for the temperature
equation in the thermocoupled model. The error analysis gives three results,
first the correct form of the Courant-Friedrichs-Lewy (CFL) condition for
stability of the advection scheme, second an equation for error growth which
contributes to understanding the famous ``spokes'' of (Payne and others, 2000),
and third a convergence theorem under stringent fixed geometry and smoothness
assumptions.


title: Influence of the disorder on tracer dispersion in a flow channel

abstract:
  Tracer dispersion is studied experimentally in periodic or disordered arrays
of beads in a capillary tube. Dispersion is measured from light absorption
variations near the outlet following a steplike injection of dye at the inlet.
Visualizations using dye and pure glycerol are also performed in similar
geometries. Taylor dispersion is dominant both in an empty tube and for a
periodic array of beads: the dispersivity $l\_d$ increases with the P\'eclet
number $Pe$ respectively as $Pe$ and $Pe^{0.82}$ and is larger by a factor of 8
in the second case. In a disordered packing of smaller beads (1/3 of the tube
diameter) geometrical dispersion associated to the disorder of the flow field
is dominant with a constant value of $l\_d$ reached at high P\'eclet numbers.
The minimum dispersivity is slightly higher than in homogeneous nonconsolidated
packings of small grains, likely due heterogeneities resulting from wall
effects. In a disordered packing with the same beads as in the periodic
configuration, $l\_d$ is up to 20 times lower than in the latter and varies as
$Pe^\alpha$ with $\alpha = 0.5$ or $= 0.69$ (depending on the fluid viscosity).
A simple model accounting for this latter result is suggested.


title: A fitness model for the Italian Interbank Money Market

abstract:
  We use the theory of complex networks in order to quantitatively characterize
the formation of communities in a particular financial market. The system is
composed by different banks exchanging on a daily basis loans and debts of
liquidity. Through topological analysis and by means of a model of network
growth we can determine the formation of different group of banks characterized
by different business strategy. The model based on Pareto's Law makes no use of
growth or preferential attachment and it reproduces correctly all the various
statistical properties of the system. We believe that this network modeling of
the market could be an efficient way to evaluate the impact of different
policies in the market of liquidity.


title: Climate simulations for 1880-2003 with GISS modelE

abstract:
  We carry out climate simulations for 1880-2003 with GISS modelE driven by ten
measured or estimated climate forcings. An ensemble of climate model runs is
carried out for each forcing acting individually and for all forcing mechanisms
acting together. We compare side-by-side simulated climate change for each
forcing, all forcings, observations, unforced variability among model ensemble
members, and, if available, observed variability. Discrepancies between
observations and simulations with all forcings are due to model deficiencies,
inaccurate or incomplete forcings, and imperfect observations. Although there
are notable discrepancies between model and observations, the fidelity is
sufficient to encourage use of the model for simulations of future climate
change. By using a fixed well-documented model and accurately defining the
1880-2003 forcings, we aim to provide a benchmark against which the effect of
improvements in the model, climate forcings, and observations can be tested.
Principal model deficiencies include unrealistically weak tropical El Nino-like
variability and a poor distribution of sea ice, with too much sea ice in the
Northern Hemisphere and too little in the Southern Hemisphere. The greatest
uncertainties in the forcings are the temporal and spatial variations of
anthropogenic aerosols and their indirect effects on clouds.


title: Formation of Languages; Equality, Hierarchy and Teachers

abstract:
  A quantitative method is suggested, where meanings of words, and grammatic
rules about these, of a vocabulary are represented by real numbers. People meet
randomly, and average their vocabularies if they are equal; otherwise they
either copy from higher hierarchy or stay idle. Presence of teachers
broadcasting the same (but arbitrarily chosen) vocabulary leads the language
formations to converge more quickly.


title: Classical evolution of fractal measures on the lattice

abstract:
  We consider the classical evolution of a lattice of non-linear coupled
oscillators for a special case of initial conditions resembling the equilibrium
state of a macroscopic thermal system at the critical point. The displacements
of the oscillators define initially a fractal measure on the lattice associated
with the scaling properties of the order parameter fluctuations in the
corresponding critical system. Assuming a sudden symmetry breaking (quench),
leading to a change in the equilibrium position of each oscillator, we
investigate in some detail the deformation of the initial fractal geometry as
time evolves. In particular we show that traces of the critical fractal measure
can sustain for large times and we extract the properties of the chain which
determine the associated time-scales. Our analysis applies generally to
critical systems for which, after a slow developing phase where equilibrium
conditions are justified, a rapid evolution, induced by a sudden symmetry
breaking, emerges in time scales much shorter than the corresponding relaxation
or observation time. In particular, it can be used in the fireball evolution in
a heavy-ion collision experiment, where the QCD critical point emerges, or in
the study of evolving fractals of astrophysical and cosmological scales, and
may lead to determination of the initial critical properties of the Universe
through observations in the symmetry broken phase.