title: Stability of Few-Charge Systems in Quantum Mechanics

abstract:
  We consider non-relativistic systems in quantum mechanics interacting through
the Coulomb potential, and discuss the existence of bound states which are
stable against spontaneous dissociation into smaller atoms or ions. We review
the studies that have been made of specific mass configurations and also the
properties of the domain of stability in the space of masses or inverse masses.
These rigorous results are supplemented by numerical investigations using
accurate variational methods. A section is devoted to systems of three
arbitrary charges and another to molecules in a world with two
space-dimensions.

categories: physics.atom-ph math-ph math.MP quant-ph


title:
Study of the Radiation Hardness of Irradiated AToM Front-End Chips of
  the BaBar Silicon Vertex Tracker

abstract:
  The radiation hardness of the AToM chips of the BaBar Silicon Vertex Tracker
has been investigated by means of irradiations with photons from a 60Co source
and 0.9 GeV electrons. The increase in noise and the decrease in gain of the
amplifier have been measured as a function of the applied capacitive load and
the absorbed dose. Different beam intensities have been used to study the
effect of different dose rates to the AToM radiation damage. The chip digital
functionalities have been tested up to a dose of 5.5 Mrads for the 60Co photons
and 9 Mrads for the 0.9 GeV electrons. In addition a pedestal shift for the
irradiated channels has been observed in the test with electrons but is not
present in the irradiation with photons. This effect reproduces qualitatively
the behavior observed since 2002 in the front-end electronics of the installed
BaBar Silicon Vertex Tracker. After some investigation of the chip layout, this
peculiar behavior could be associated to radiation damage in a well-identified
component of the AToM. The results of the radiation tests are presented and
used to extrapolate the performance and lifetime of the installed detector in
the next few years.


title:
Leave-one-out prediction error of systolic arterial pressure time series
  under paced breathing

abstract:
  In this paper we show that different physiological states and pathological
conditions may be characterized in terms of predictability of time series
signals from the underlying biological system. In particular we consider
systolic arterial pressure time series from healthy subjects and Chronic Heart
Failure patients, undergoing paced respiration. We model time series by the
regularized least squares approach and quantify predictability by the
leave-one-out error. We find that the entrainment mechanism connected to paced
breath, that renders the arterial blood pressure signal more regular, thus more
predictable, is less effective in patients, and this effect correlates with the
seriousness of the heart failure. The leave-one-out error separates controls
from patients and, when all orders of nonlinearity are taken into account,
alive patients from patients for which cardiac death occurred.


title: Stabilization of nonlinear plasma waves by radiation

abstract:
  It is shown that the interaction of a plasma with thermal radiation leads to
the stabilization of both periodic and solitary nonlinear plasma waves. The
stabilized periodic nonlinear plasma waves were indeed observed in the
experiment carried out by Looney and Brown. There are many branches of
radiation-induced solitary waves in plasmas, corresponding in particular to the
density waves in hot plasmas of accretion disks.


title: Suppression of left-handed properties in disordered metamaterials

abstract:
  We study the effect of disorder on the effective magnetic response of
composite left-handed metamaterials and their specific properties such as
negative refraction. We show that relatively weak disorder in the split-ring
resonators can reduce and even completely eliminate the frequency domain where
the composite material demonstrates the left-handed properties. We introduce
the concept of the order parameter to describe novel physics of this effect.


title:
Electronic Quantum Monte Carlo Calculations of Atomic Forces,
  Vibrations, and Anharmonicities

abstract:
  Atomic forces are calculated for first-row monohydrides and carbon monoxide
within electronic quantum Monte Carlo (QMC). Accurate and efficient forces are
achieved by using an improved method for moving variational parameters in
variational QMC. Newton's method with singular value decomposition (SVD) is
combined with steepest descent (SD) updates along directions rejected by the
SVD, after initial SD steps. Dissociation energies in variational and diffusion
QMC agree well with experiment. The atomic forces agree quantitatively with
potential energy surfaces, demonstrating the accuracy of this force procedure.
The harmonic vibrational frequencies and anharmonicity constants, derived from
the QMC energies and atomic forces, also agree well with experimental values.


title: Three Different Sizes Obtained Using Light Scattering Techniques

abstract:
  The average scattered intensity is determined by the optical characteristics
of particles in dispersion. The normalized time auto-correlation function of
the scattered light intensity $g^{(2)}(\tau) $ includes both the optical and
hydrodynamic information of particles. From the different characteristics of
particles, the particle sizes can be obtained. In this paper, three sizes: the
static radius $R_{s}$, the hydrodynamic radius $R_{h}$ and the apparent
hydrodynamic radius $R_{h,app}$ are discussed using dilute water dispersions of
homogenous spherical particles poly($N$-isopropylacrylamide) microgels, with a
simple assumption that the hydrodynamic radius is in proportion to the static
radius, when Rayleigh-Gans-Debye approximation is valid. Our results show that
the expected values of the normalized time auto-correlation function of the
scattered light intensity are consistent with the experimental data very well
and the difference between the static radius and the apparent hydrodynamic
radius is large and the difference between the hydrodynamic radius and the
apparent hydrodynamic radius is influenced by the particle size distribution.


title: A Coupled Cavity Micro Fluidic Dye Ring Laser

abstract:
  We present a laterally emitting, coupled cavity micro fluidic dye ring laser,
suitable for integration into lab-on-a-chip micro systems. The micro-fluidic
laser has been successfully designed, fabricated, characterized and modelled.
The resonator is formed by a micro-fluidic channel bounded by two isosceles
triangle mirrors. The micro-fluidic laser structure is defined using photo
lithography in 10 microns thick SU-8 polymer on a glass substrate. The micro
fluidic channel is sealed by a glass lid, using PMMA adhesive bonding. The
laser is characterized using the laser dye Rhodamine 6G dissolved in ethanol or
ethylene glycol as the active gain medium, which is pumped through the
micro-fluidic channel and laser resonator. The dye laser is optically pumped
normal to the chip plane at 532 nm by a pulsed, frequency doubled Nd:YAG laser
and lasing is observed with a threshold pump pulse energy flux of around 55
micro-Joule/square-milimeter. The lasing is multi-mode, and the laser has
switchable output coupling into an integrated polymer planar waveguide. Tuning
of the lasing wavelength is feasible by changing the dye/solvent properties.


title:
Calibration of second-order correlation functions for non-stationary
  sources with a multi-start multi-stop time-to-digital converter

abstract:
  A novel high-throughput second-order-correlation measurement system is
developed which records and makes use of all the arrival times of photons
detected at both start and stop detectors. This system is suitable particularly
for a light source having a high photon flux and a long coherence time since it
is more efficient than conventional methods by an amount equal to the product
of the count rate and the correlation time of the light source. We have used
this system in carefully investigating the dead time effects of detectors and
photon counters on the second-order correlation function in the two-detector
configuration. For a non-stationary light source, distortion of original signal
was observed at high photon flux. A systematic way of calibrating the
second-order correlation function has been devised by introducing a concept of
an effective dead time of the entire measurement system.


title:
Towards an experimental von Karman dynamo: numerical studies for an
  optimized design

abstract:
  Numerical studies of a kinematic dynamo based on von Karman type flows
between two counterrotating disks in a finite cylinder are reported. The flow
has been optimized using a water model experiment, varying the driving
impellers configuration. A solution leading to dynamo action for the mean flow
has been found. This solution may be achieved in VKS2, the new sodium
experiment to be performed in Cadarache, France. The optimization process is
described and discussed, then the effects of adding a stationary conducting
layer around the flow on the threshold, on the shape of the neutral mode and on
the magnetic energy balance are studied. Finally, the possible processes
involved into kinematic dynamo action in a von Karman flow are reviewed and
discussed. Among the possible processes we highlight the joint effect of the
boundary-layer radial velocity shear and of the Ohmic dissipation localized at
the flow/outer-shell boundary.


title: Fluence Dependence of Charge Collection of irradiated Pixel Sensors

abstract:
  The barrel region of the CMS pixel detector will be equipped with ``n-in-n''
type silicon sensors. They are processed on DOFZ material, use the moderated
p-spray technique and feature a bias grid. The latter leads to a small fraction
of the pixel area to be less sensitive to particles. In order to quantify this
inefficiency prototype pixel sensors irradiated to particle fluences between
$4.7\times 10^{13}$ and $2.6\times 10^{15} \Neq$ have been bump bonded to
un-irradiated readout chips and tested using high energy pions at the H2 beam
line of the CERN SPS. The readout chip allows a non zero suppressed analogue
readout and is therefore well suited to measure the charge collection
properties of the sensors.
  In this paper we discuss the fluence dependence of the collected signal and
the particle detection efficiency. Further the position dependence of the
efficiency is investigated.


title:
Calculations of liquid helium and neon VUV emission spectra,
  self-absorption and scattering for a neutrino detector

abstract:
  To evaluate the feasibility of the recently proposed detection scheme of low
energy neutrinos released from the Sun and supernovae called CLEAN, Cryogenic
Low Energy Astrophysics with Noble Gases, which relies on the transparency of
noble-gas cryogenic liquids to VUV radiation produced by neutrinos, we analyze
theoretically VUV emission, self-absorption, and scattering of liquid helium
and neon, primary candidates for CLEAN. Owing to strong repulsion of noble-gas
atoms in the ground states at the equilibrium distance of the relevant excited
state, the emission spectrum is substantially shifted from the absorption
spectrum, and in principle the absorption is expected very small, allowing
building large detectors. Our analysis, however, shows that the self-absorption
and Rayleigh scattering are comparable to the size of the proposed detector.
  Our theoretical emission spectra are found in agreement with experimental
observations although some deviation exists due to binary-interaction
approximation, and our ab initio Rayleigh scattering lengths are found in
agreement with other calculations based on the extrapolation of experimental
refraction indices. The absorption process can result in either re-emission,
which conserves the number of photons but delays their escape from the liquid,
or in non-radiative quenching.


title: The Neutrino Matrix

abstract:
  To answer the very interesting questions raised by the discovery of neutrino
mass, an effective, coherent strategy is needed. To foster the development of
such a strategy, the American Physical Society's Divisions of Nuclear Physics
and of Particles and Fields, together with the Divisions of Astrophysics and
the Physics of Beams, have sponsored this yearlong Study on the Physics of
Neutrinos. The study has endeavored to identify the most important open
questions, to evaluate the physics reach of various proposed ways of answering
them, and to determine an effective, fruitful U.S. role within a global
experimental program. An important -- if challenging -- goal of the study has
been to achieve consensus regarding the future of neutrino physics.

categories: physics.pop-ph astro-ph hep-ex nucl-ex nucl-th


title:
Proposal of Michelson-Morley experiment via single photon
  interferometer: Interpretation of Michelson-Morley experimental results using
  de Broglie-Bohm picture

abstract:
  The Michelson-Morley experiment is considered via a single photon
interferometer and we propose the interpretation of the Michelson-Morley
experimental results using de Broglie-Bohm picture. We point out that the
Michelson-Morley experiment revealed the interference of photons, however, it
did not reveal the photons simultaneous arrival at the beam splitter. According
to the de Broglie-Bohm picture, the quantum potential nonlocally determines the
interference of photons. The interference of the photons is not governed by the
arrival time of the photons; rather, it is governed by the quantum potential.
Therefore, there is a possibility for another interpretation of the
Michelson-Morley experimental results.


title: Muon Acceleration using Fixed Field, Alternating Gradient (FFAG) Rings

abstract:
  Given their 2.2 microsecond lifetime, muons must be accelerated fairly
rapidly for a neutrino factory or muon collider. Muon bunches tend to be large.
Progress in fixed field, alternating gradient (FFAG) lattices to meet this
challenge is reviewed. FFAG magnets are naturally wide; low momentum muons move
from the low field side of a gradient magnet to the high field side as they
gain energy. This can be exploited to do double duty and allow a large beam
admittance without unduly increasing the magnetic field volume. If the amount
of RF must be reduced to optimize cost, an FFAG ring can accommodate extra
orbits. I describe both scaling FFAGs in which the bends in each magnet are
energy independent and non-scaling FFAGs in which the bends in each magnet do
vary with muon energy. In all FFAG designs the sum of the bends in groups of
magnets are constant; otherwise orbits would not close. Ways of keeping the
accelerating beam in phase with the RF are described. Finally, a 1 MeV proof of
principle scaling FFAG has been built at KEK and began accelerating protons in
June 2000 with a 1 kHz repetition rate.


title: Special Relativity for the School Going Child

abstract: An elementary account of special relativity for school-children.


title:
Probing Dynamics at Interfaces: Options for Neutron and X-ray
  Spectroscopy

abstract:
  Inelastic neutron and X-ray scattering experiments on surfaces and interfaces
are a challenging topic in modern physics. Particular interest arises regarding
surfaces and interfaces of soft matter and biological systems. We review both
neutron and x-ray spectroscopic techniques with view at their applicability to
these samples. We discuss the different methods, namely neutron triple-axis,
backscattering and spin-echo spectroscopy as well as x-ray photon correlation
spectroscopy, in the context of planar lipid membrane models as an example. By
the combination of the different methods, a large range in momentum and energy
transfer is accessible.


title:
Strong-field ionization of diatomic molecules and companion atoms:
  strong-field approximation and tunneling theory including nuclear motion

abstract:
  We present a detailed comparison of strong-field ionization of diatomic
molecules and their companion atoms with nearly equal ionization potentials. We
perform calculations in the length and velocity gauge formulations of the
molecular strong-field approximation and with the molecular tunneling theory,
and in both cases we consider effects of nuclear motion. A comparison of our
results with experimental data shows that the length gauge strong-field
approximation gives the most reliable predictions.


title:
The dependence of transverse and longitudinal resolutions on incident
  Gaussian beam widths in the illumination part of optical scanning microscopy

abstract:
  We studied both theoretically and experimentally the intensity distribution
of a Gaussian laser beam when it was focussed by an objective lens with its
numerical-aperture (NA) up to 0.95. Approximate formulae for full widths at
half maximum (FWHM) of the intensity distribution at focus were derived for
very large and very small initial beam waists with respect to the entrance
pupil radius of the objective lens. In experiments the energy flux through a
0.5 micron pinhole was measured for various pinhole positions. We found that
the FWHM's at focus in the transverse and the longitudinal directions do not
increase much from the ultimate FWHM's until the input beam waist is reduced
below the half of the entrance pupil radius. In addition, we observed
significance of the spatial distribution of the input beam against a true
Gaussian beam profile in the case of small initial beam waist. For high NA with
resulting focal beam waists comparable to or smaller than the wavelength of the
laser, the interaction between the electric field and the conducting surface of
the pinhole caused the transverse FWHM to be measured slightly smaller than
FWHM of the unperturbed intensity distribution convoluted with the pinhole
opening.


title: Shape resonances in nested diffraction gratings

abstract:
  The diffraction problem of a plane wave impinging on a grating formed by
nested cavities is solved by means of the modal method, for $s$ and $p$
polarization modes. The cavities are formed by perfectly conducting sheets that
describe rectangular profiles. The electromagnetic response of the grating is
analyzed, paying particular attention to the generation of resonances within
the structure. The dependence of the resonances on the geometrical parameters
of the grating is studied, and results of far and near field are shown. The
results are checked and compared with those available in the literature for
certain limit cases.


title: The Mysterious Dark Energy

abstract:
  The concept of an all pervading Aether is age old, and contrary to popular
belief, it survived the twentieth century too though with different nuances.
Using this concept of a background Quantum Vacuum, the author in 1997 proposed
a cosmological model with some resemblance to the Dirac cosmology, which
correctly predicted a dark energy driven accelerating universer with a small
cosmological constant, as was subsequently confirmed by observation in 1998.
Moreover the so called Large Number coincidences including the mysterious
Weinberg formula are deduced in this theory, rather than being ad hoc. We
examine the concept of Aether in this context and indicate how this dark energy
may be harnessed.


title: Stochastic Dynamics of Magnetosomes in Cytoskeleton

abstract:
  Rotations of microscopic magnetic particles, magnetosomes, embedded into the
cytoskeleton and subjected to the influence of an ac magnetic field and thermal
noise are considered. Magnetosome dynamics is shown to comply with the
conditions of the stochastic resonance under not-too-tight constraints on the
character of the particle's fastening. The excursion of regular rotations
attains the value of order of radian that facilitates explaining the biological
effects of low-frequency weak magnetic fields and geomagnetic fluctuations.
Such 1-rad rotations are effectively controlled by slow magnetic field
variations of the order of 200 nT.


title:
A suggested search for 207Pb nuclear Schiff moment in PbTiO3
  ferroelectric

abstract:
  We suggest two types of experiments, NMR and macroscopic magnetometry, with
solid PbTiO3 to search for the nuclear Schiff moment of 207Pb. Both kinds of
experiments promise substantial improvement over the presently achieved
sensitivities. Statistical considerations show that the improvement of the
current sensitivity can be up to 10 orders of magnitude for the magnetometry
experiment and up to 6 orders of magnitude for the NMR experiment. Such
significant enhancement is due to the strong internal electric field of the
ferroelectric, as well as due to the possibility to cool the nuclear-spin
subsystem in the compound down to nanokelvin temperatures.

categories: physics.atom-ph cond-mat.other hep-ph nucl-th


title:
On the measurement of frequency and of its sample variance with
  high-resolution counters

abstract:
  A frequency counter measures the input frequency $\bar{\nu}$ averaged over a
suitable time $\tau$, versus the reference clock. High resolution is achieved
by interpolating the clock signal. Further increased resolution is obtained by
averaging multiple frequency measurements highly overlapped. In the presence of
additive white noise or white phase noise, the square uncertainty improves from
$\smash{\sigma^2_\nu\propto1/\tau^2}$ to $\smash{\sigma^2_\nu\propto1/\tau^3}$.
Surprisingly, when a file of contiguous data is fed into the formula of the
two-sample (Allan) variance
$\smash{\sigma^2_y(\tau)=\mathbb{E}\{\frac12(\bar{y}_{k+1}-\bar{y}_k) ^2\}}$ of
the fractional frequency fluctuation $y$, the result is the \emph{modified}
Allan variance mod $\sigma^2_y(\tau)$. But if a sufficient number of contiguous
measures are averaged in order to get a longer $\tau$ and the data are fed into
the same formula, the results is the (non-modified) Allan variance. Of course
interpretation mistakes are around the corner if the counter internal process
is not well understood.


title: A Scintillating-fiber Beam Profile Monitor for the DAFNE BTF

abstract:
  A scintillating-fiber beam profile detector has been designed, built and
tested, for the monitoring of the position and size of the electron beam of the
DAFNE, the recently commissioned electron beam-test facility at the Frascati
LNF. A description of the detector construction and assembly, together with the
results achieved during the 2003-2004 run, are here reported.


title: Rectangular Parallelepiped Vibration in Plane Strain State

abstract:
  In this paper we present a vibration spectrum of a homogenous parallelepiped
(HP) under the action of volume and surface forces resulting from the exponent
displacements entering the Fourier transforms. Vibration under the action of
axial surface tractions and the free vibration are described separately. A
relationship between the high frequency vibration and boundary conditions (BC)
is also considered.


title: Magnetic turbulence in the plasma sheet

abstract:
  Small-scale magnetic turbulence observed by the Cluster spacecraft in the
plasma sheet is investigated by means of a wavelet estimator suitable for
detecting distinct scaling characteristics even in noisy measurements. The
spectral estimators used for this purpose are affected by a frequency dependent
bias. The variances of the wavelet coefficients, however, match the power-law
shaped spectra, which makes the wavelet estimator essentially unbiased. These
scaling characteristics of the magnetic field data appear to be essentially
non-steady and intermittent. The scaling properties of bursty bulk flow (BBF)
and non-BBF associated magnetic fluctuations are analysed with the aim of
understanding processes of energy transfer between scales. Small-scale ($\sim
0.08-0.3$ s) magnetic fluctuations having the same scaling index $\alpha \sim
2.6$ as the large-scale ($\sim 0.7-5$ s) magnetic fluctuations occur during
BBF-associated periods. During non-BBF associated periods the energy transfer
to small scales is absent, and the large-scale scaling index $\alpha \sim 1.7$
is closer to Kraichnan or Iroshnikov-Kraichnan scalings. The anisotropy
characteristics of magnetic fluctuations show both scale-dependent and
scale-independent behavior. The former can be partly explained in terms of the
Goldreich-Sridhar model of MHD turbulence, which leads to the picture of
Alfv\'{e}nic turbulence parallel and of eddy turbulence perpendicular to the
mean magnetic field direction. Nonetheless, other physical mechanisms, such as
transverse magnetic structures, velocity shears, or boundary effects can
contribute to the anisotropy characteristics of plasma sheet turbulence. The
scale-independent features are related to anisotropy characteristics which
occur during a period of magnetic reconnection and fast tailward flow.


title: On Onsager Relations and Linear Electromagnetic Materials

abstract:
  We investigated the Onsager relations in the context of electromagnetic
constitutive relations of linear, homogeneous materials. We determined that
application of the Onsager relations to the constitutive equations relating
$#P$ and $#M$ to both $#E$ and $#B$ is in accord with Lorentz reciprocity as
well as the Post constraint.


title:
220 fs Er-Yb:glass laser mode-locked by a broadband low-loss Si/Ge
  saturable absorber

abstract:
  We demonstrate femtosecond performance of an ultra-broadband
high-index-contrast saturable Bragg reflector consisting of a
silicon/silicon-dioxide/germanium structure that is fully compatible with CMOS
processing. This device offers a reflectivity bandwidth of over 700 nm and
sub-picosecond recovery time of the saturable loss. It is used to achieve
mode-locking of an Er-Yb:glass laser centered at 1540 nm, generating 220 fs
pulses, with the broadest output spectrum to date.


title: Differential aging from acceleration, an explicit formula

abstract:
  We consider a clock 'paradox' framework where an observer leaves an inertial
frame, is accelerated and after an arbitrary trip comes back. We discuss a
simple equation that gives, in the 1+1 dimensional case, an explicit relation
between the time elapsed on the inertial frame and the acceleration measured by
the accelerating observer during the trip.
  A non-closed trip with respect to an inertial frame appears closed with
respect to another suitable inertial frame. Using this observation we define
the differential aging as a function of proper time and show that it is
non-decreasing. The reconstruction problem of special relativity is also
discussed showing that its, at least numerical, solution would allow the
construction of an 'inertial clock'.


title:
Excitation of guided waves in layered structures with negative
  refraction

abstract:
  We study the electromagnetic beam reflection from layered structures that
include the so-called double-negative materials, also called left-handed
metamaterials. We predict that such structures can demonstrate a giant lateral
Goos-Hanchen shift of the scattered beam accompanied by splitting of the
reflected and transmitted beams due to the resonant excitation of surface waves
at the interfaces between the conventional and double-negative materials as
well as due to excitation of leaky modes in the layered structures. The beam
shift can be either positive or negative, depending on the type of the guided
waves excited by the incoming beam. We also perform finite-difference
time-domain simulations and confirm the major effects predicted analytically.


title: On linear coupling of acoustic and cyclotron waves in plasma flows

abstract:
  It is found that in magnetized electrostatic plasma flows the velocity shear
couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable
conditions, to their efficient reciprocal transformations. It is shown that in
a two-dimensional setup this coupling has a remarkable feature: it is governed
by equations that are exactly similar to the ones describing coupling of sound
waves with internal gravity waves [Rogava & Mahajan: Phys. Rev. E vol.55, 1185
(1997)] in neutral fluid flows. Using another noteworthy quantum mechanical
analogy we calculate transformation coefficients and give fully analytic,
quantitative description of the coupling efficiency for flows with low shearing
rates.


title:
Validation of the GATE Monte Carlo simulation platform for modelling a
  CsI(Tl) scintillation camera dedicated to small animal imaging

abstract:
  Monte Carlo simulations are increasingly used in scintigraphic imaging to
model imaging systems and to develop and assess tomographic reconstruction
algorithms and correction methods for improved image quantitation. GATE (GEANT
4 Application for Tomographic Emission) is a new Monte Carlo simulation
platform based on GEANT4 dedicated to nuclear imaging applications. This paper
describes the GATE simulation of a prototype of scintillation camera dedicated
to small animal imaging and consisting of a CsI(Tl) crystal array coupled to a
position sensitive photomultiplier tube. The relevance of GATE to model the
camera prototype was assessed by comparing simulated 99mTc point spread
functions, energy spectra, sensitivities, scatter fractions and image of a
capillary phantom with the corresponding experimental measurements. Results
showed an excellent agreement between simulated and experimental data:
experimental spatial resolutions were predicted with an error less than 100 mu
m. The difference between experimental and simulated system sensitivities for
different source-to-collimator distances was within 2%. Simulated and
experimental scatter fractions in a [98-182 keV] energy window differed by less
than 2% for sources located in water. Simulated and experimental energy spectra
agreed very well between 40 and 180 keV. These results demonstrate the ability
and flexibility of GATE for simulating original detector designs. The main
weakness of GATE concerns the long computation time it requires: this issue is
currently under investigation by the GEANT4 and the GATE collaborations


title: Relativistic Field Theory of Fluids

abstract:
  Classical relativistic field theory is applied to perfect and
magneto-hydrodynamic flows. The fields for Hamilton's principle are shown to be
the Lagrangian coordinates of the fluid elements, which are potentials for the
matter current 4-vector and the electromagnetic field 2-form. The energy
momentum tensor and equations of motion are derived from the fields. In this
way the theory of continua is shown to have the same form as other field
theories, such as electromagnetism and general relativity.
  Waves are treated as an example of the power of field theoretic methods. The
average or background flow and the waves are considered as two interacting
components of the system. The wave-background interaction involves the transfer
of energy and momentum between the waves and the average flow, but the total
energy and momentum are conserved. The average Lagrangian for the total
wave-background system is found by expanding the Lagrangian about the
background flow and averaging over the phase. The total energy-momentum tensor
is constructed, and the conservation of energy and momentum are discussed.
Varying the wave amplitude gives the dispersion and polarization relations for
the waves, and varying the phase gives the rays and conservation of wave quanta
(or wave action). The wave quanta move with the group velocity along the
bi-characteristic rays.


title:
Resonance modes in a 1D medium with two purely resistive boundaries:
  calculation methods, orthogonality and completeness

abstract:
  Studying the problem of wave propagation in media with resistive boundaries
can be made by searching for "resonance modes" or free oscillations regimes. In
the present article, a simple case is investigated, which allows one to
enlighten the respective interest of different, classical methods, some of them
being rather delicate. This case is the 1D propagation in a homogeneous medium
having two purely resistive terminations, the calculation of the Green function
being done without any approximation using three methods. The first one is the
straightforward use of the closed-form solution in the frequency domain and the
residue calculus. Then the method of separation of variables (space and time)
leads to a solution depending on the initial conditions. The question of the
orthogonality and completeness of the complex-valued resonance modes is
investigated, leading to the expression of a particular scalar product. The
last method is the expansion in biorthogonal modes in the frequency domain, the
modes having eigenfrequencies depending on the frequency. Results of the three
methods generalize or/and correct some results already existing in the
literature, and exhibit the particular difficulty of the treatment of the
constant mode.


title: Photoionization of the fullerene ion C60+

abstract:
  Photoionization cross section of the fullerene ion C60+ has been calculated
within a single-electron approximation and also by using a consistent many-body
theory accounting for many-electron correlations.


title: Copernican Cosmography in the First Mexican Physics Treatise

abstract:
  Copernican Cosmography was used to discover the path linking Cebu islands and
Acapulco via Kuro-Shivo Stream, as registered in Physica Speculatio, first
physics book written in New Spain. Teaching and practice of Copernican theory
were an outcome of both Spanish expansion into the Pacific Ocean and native
elite instruction devised by Augustinian friars. Copernican cosmography was
explained in Physica Speculatio's first edition in addition to the reference
given by Alonso de la Veracruz about the use of Copernican theory to detect
Pacific Islands in Physica Speculatio's Fourth edition. Also, Veracroce
standpoint about the differences between physics and mathematics is discussed
in terms of its relation to the rejection of the Copernican Theory as a Natural
Theory.


title:
Calculation of The Critical Point for Two-Layer Ising and Potts Models
  Using Cellular Automata

abstract:
  The critical points of the two-layer Ising and Potts models for square
lattice have been calculated with high precision using probabilistic cellular
automata (PCA) with Glauber algorithm. The critical temperature is calculated
for the isotropic and symmetric case (Kx=Ky=Kz=K), where Kx and Ky are the
nearest-neighbor interactions within each layer in the x and y directions,
respectively, and Kz is the interlayer coupling. The obtained results are 0.310
and 0.726 for two-layer Ising and Potts models, respectively, that are in good
agreement with the accurate values reported by others.


title:
Directed Ligand Passage Over the Surface of Diffusion-Controlled
  Enzymes: A Cellular Automata Model

abstract:
  The rate-limiting step of some enzymatic reactions is a physical step, i.e.
diffusion. The efficiency of such reactions can be improved through an increase
in the arrival rate of the substrate molecules, e.g. by a directed passage of
substrate (ligand) to active site after its random encounter with the enzyme
surface. Herein, we introduce a cellular automata model simulating the ligand
passage over the protein surface to its destined active site. The system is
simulated using the lattice gas automata with probabilistic transition rules.
Different distributions of amino acids over the protein surface are examined.
For each distribution, the hydration pattern is achieved and the mean number of
iteration steps needed for the ligand to arrive at the active site calculated.
Comparison of results indicates that the rate at which ligand arrives at the
active site is clearly affected by the distribution of amino acids outside the
active side. Such a process can facilitate the ligand diffusion towards the
active site thereby enhancing the efficiency of the enzyme action.


title:
Alternative method for wave propagation analysis within bounded linear
  media: conceptual and practical implications

abstract:
  This paper uses an alternative approach to study the monochromatic plane wave
propagation within dielectric and conductor linear media of
plane-parallel-faces. This approach introduces the time-averaged Poynting
vector modulus as field variable. The conceptual implications of this formalism
are that the nonequivalence between the time-averaged Poynting vector and the
squared-field amplitude modulus is naturally manifested as a consequence of
interface effects. Also, two practical implications are considered: first, the
exact transmittance is compared with that given by the Beer's Law, employed
commonly in experiments. The departure among them can be significative for
certain material parameter values. Second, when the exact reflectance is
studied for negative permittivity slabs, it is show that the high reflectance
can be diminished if a small amount of absorption is present.


title: On the satiability of floating bodies

abstract:
  The potential energy of a system in stable equilibrium has a minimum value.
This property is used to derive a formula that is useful in determi- nation of
stability of a floating body. It is found that a floating body is in stable
equilibrium if its center of gravity has a minimum height with respect to its
related center of buoyancy.


title: Gravity between Internally Electrodynamic Particles

abstract:
  We present a first-principles' prediction that two charged particles of
masses M_1 and M_2 separated R apart in a dielectric vacuum act on each other
always an attractive force in addition to other known forces in between. This
component attractive force on one charge results as the Lorentz force in the
radiation depolarization- and magnetic- fields of the other charge, being an
attractive radiation force, and is in addition to the ordinary repulsive
radiation force. The exact solution for the attractive radiation force is
F_g=G' M_1M_2/R^2, an identical formula to Newton's law of gravitation.
G'=\chi_{0^*}e^4/4\pi\epsilon_0^2\hbar^2\rho_l is identifiable with Newton's
gravitational constant, \chi_{0^*} being the susceptibility and \rho_l the
linear mass density of the vacuum, and the remaining fundamental constants of
the usual meaning. The F_g force is conveyed by a transverse vacuuonic
dipole-moment wave traveling at the velocity of light and can penetrate matter
freely. In all of respects, the F_g force represents a viable cause of Newton's
universal gravity.


title:
The disaster of the Nazi-power in science as reflected by some leading
  journals and scientists in physics - A bibliometric study

abstract:
  The consequences of the Nazi-power for the scientific process are described
qualitatively in various articles and books. However, recent progress in
information systems allows a quantitative reflection. Literature databases
ranging back to the beginning of the 20th century, the ISI citation indexes
ranging back to 1945 now and sophisticated search systems are suitable tools
for this purpose. In this study the overall break in the scientific
productivity and that of selected physical journals are examined. An overview
of the citation impact of some 50 leading physicists is given. The productivity
before and after departure is analyzed and connected to biographical data.


title:
Screened self-energy correction to the 2p3/2-2s transition energy in
  Li-like ions

abstract:
  We present an ab initio calculation of the screened self-energy correction
for (1s)^2 2p3/2 and (1s)^2 2s states of Li-like ions with nuclear charge
numbers in the range Z = 12-100. The evaluation is carried out to all orders in
the nuclear-strength parameter Z \alpha. This investigation concludes our
calculations of all two-electron QED corrections for the 2p3/2-2s transition
energy in Li-like ions and thus considerably improves theoretical predictions
for this transition for high-Z ions.


title:
Piecewise continuous partition function method in the theory of wave
  perturbations of inhomogeneous gas

abstract:
  The problem of wave disturbance propagation in rarefied gas in gravity field
is explored. The system of hydrodynamic-type equations for a stratified gas in
gravity field is derived from BGK equation by method of piecewise continuous
partition function. The obtained system of the equations generalizes the
Navier-Stokes at arbitrary density (Knudsen numbers). The verification of the
model is made for a limiting case of a homogeneous medium. Results are in the
good agreement with experiment and former theories at arbitrary Knudsen
numbers.


title: Compact magneto-optical sources of slow atoms

abstract:
  Three different configurations of compact magneto-optical sources of slow Rb
atoms(LVIS, 2D(+)-MOT and 2D-MOT) were compared with each other at fixed
geometry of cooling laser beams. A precise control of the intensity balances
between the four separate transverse cooling laser beams provided a total
continuous flux of cold atoms from the LVIS and 2D(+)-MOT sources about 8x10^9
atoms/s at total laser power of 60 mW. The flux was measured directly from the
loading rate of a 3D-MOT, placed 34 cm downstream from the sources. Average
velocities of the cooled atomic beam for the LVIS and 2D(+)-MOT sources were
about 8.5 m/s and 11 m/s respectively. An essential advantage of the compact
magneto-optical sources is that their background flux of thermal atoms is two
to three orders of the magnitude smaller than the flux of slow atoms.


title: Fluids as transducers of gravity in biological systems

abstract:
  A qualitative model is presented, suggesting gravitational information is
transduced into biological systems primarily by its effect on spatially
organised membrane and cytoplasmic flows. Continuous low affinity interactions
between membrane bound cytoskeletal proteins and phospholipid flows that are
undergoing forced convective and shear driven flows are shown to convert this
information into spatial protein patterns, and hence cell shape. As applied
here to plant cells, the feedback mechanism is shown capable not only of
establishing the strict nanometer scale parallelism that exists between
proteins running on the inside and outside of the cell membrane, but also to
predict its maintainance and the angle of fibre realignment observed during
tropic responses.


title:
Some Important Concepts in Nonstandard Analysis Theory of Turbulence(The
  revised)

abstract:
  Some important concepts in the nonstandard analysis theory of turbulence are
presented in this article. The structure of point, on which differential
equations are defined, is analyzed. The distinction between the uniform point
and the non-uniform point, as well as between the standard point and the
nonstandard point, is showed. A new kind of equations, which differ essentially
from those in existent theory, is emphasized. These new equations can hold at
non-uniform points. The applicability of the Navier-Stokes equations to
turbulence is discussed. Some illustrations of the nonstandard analysis theory
of turbulence are given too.


title: Comparison of warm and cold photon colliders

abstract:
  Photon collider based on cold and warm linear collider technologies are
compared from the point of view of attainable luminosities, technical
feasibility of laser systems and experimental conditions.


title: A conception of the photon collider beam dump

abstract:
  Photon beams at photon colliders are very narrow, powerful and can not be
deflected. For the beam dump at the TESLA-like collider we suggest to use a
long gas (Ar) spoiler in front of the water absorber, this solves the
overheating and mechanical stress problems. The neutron background at the
interaction point is estimated.


title: Why the phase shifts for solitons on a vortex filament are so large?

abstract:
  The phase ``jumps'' for solitons interacting on a vortex filament, observed
in experiments, have been unaccounted for since more than twenty years. Using
explicit formulas describing the interaction of two solitons on a thin vortex
filament in the Localized Induction Approximation we show that an appropriate
choice of the parameters of the solitons leads to large phase shifts. This
result does not depend on the axial flow along the filament.


title:
Polarization mode interaction equations in optical fibers with Kerr
  effect

abstract:
  We derive coupled nonlinear Schr\"{o}dinger equation (CNLSE) for arbitrary
polarized light propagation in a single-mode fiber. We introduce a basis of
transverse eigen modes with the appropriate projecting hence solutions depend
on the waveguide geometry. Considering a weak nonlinearity which is connected
with Kerr effect, we give explicit expressions for nonlinear constants via
integrals of Bessel functions. We compare numerical results for the nonlinear
constant extracted from experimental observations of a soliton for the
nonlinear Schr\"{o}dinger equation (NLSE) (single-mode one). The method of
projecting we use allows a direct generalization to multi-mode fiber case.


title: New distributed offline processing scheme at Belle

abstract:
  The offline processing of the data collected by the Belle detector has been
recently upgraded to cope with the excellent performance of the KEKB
accelerator. The 127/fb of data (120 TB on tape) collected between autumn 2003
and summer 2004 has been processed in 2 months, thanks to the high speed and
stability of the new, distributed processing scheme. We present here this new
processing scheme and its performance.


title:
Nonlinear absorption and dispersion in fiber-taper-coupled silicon
  photonic crystal microresonators

abstract:
  A technique is demonstrated which efficiently transfers light between a
tapered standard single-mode optical fiber and a high-Q, ultra-small mode
volume, silicon photonic crystal resonant cavity. Cavity mode quality factors
of 47000 are measured, and a total fiber-to-cavity coupling efficiency of 44%
is demonstrated. Using this efficient cavity input and output channel, the
steady-state nonlinear absorption and dispersion of the photonic crystal cavity
is studied. Optical bistability is observed for fiber input powers as low as
250 \mu W, corresponding to a dropped power of 100 \mu W and 3 fJ of stored
cavity energy. A high-density effective free-carrier lifetime for these silicon
photonic crystal resonators of 0.5 ns is also estimated from power dependent
loss and dispersion measurements.


title:
Development and operation of a pixel segmented liquid-filled linear
  array for radiotherapy quality assurance

abstract:
  A liquid isooctane (C$_{8}$H$_{18}$) filled ionization linear array for
radiotherapy quality assurance has been designed, built and tested. The
detector consists of 128 pixels, each of them with an area of 1.7 mm $\times$
1.7 mm and a gap of 0.5 mm. The small pixel size makes the detector ideal for
high gradient beam profiles like those present in Intensity Modulated Radiation
Therapy (IMRT) and radiosurgery. As read-out electronics we use the X-Ray Data
Acquisition System (XDAS) with the Xchip developed by the CCLRC.
  Studies concerning the collection efficiency dependence on the polarization
voltage and on the dose rate have been made in order to optimize the device
operation.
  In the first tests we have studied dose rate and energy dependences, and
signal reproducibility. Dose rate dependence was found lower than 2.5 % up to 5
Gy min$^{-1}$, and energy dependence lower than 2.1 % up to 20 cm depth in
solid water. Output factors and penumbras for several rectangular fields have
been measured with the linear array and were compared with the results obtained
with a 0.125 cm$^{3}$ air ionization chamber and radiographic film,
respectively. Finally, we have acquired profiles for an IMRT field and for a
virtual wedge. These profiles have also been compared with radiographic film
measurements. All the comparisons show a good correspondence. Signal
reproducibility was within a 2% during the test period (around three months).
  The device has proved its capability to verify on-line therapy beams with
good spatial resolution and signal to noise ratio.


title:
Some consequences of the Einstein covariance principle in
  electrodynamics of media

abstract:
  We show that the Einstein covariance principle provides an opportunity to
generate infinitely many solutions of given covariant equation from a known
one. With use of this statement we derive exact expressions for charge and
current densities in a medium in an arbitrary external field. We obtain that in
a homogeneous nondispersive medium the field of a point particle differs at
short-distances from the well known expression. We also demonstrate that in a
linear medium second harmonic generation and optical detection become possible
in the field of radially polarized radiation.


title: Patch dynamics with buffers for homogenization problems

abstract:
  An important class of problems exhibits smooth behaviour on macroscopic space
and time scales, while only a microscopic evolution law is known. For such
time-dependent multi-scale problems, an "equation-free" framework has been
proposed, of which patch dynamics is an essential component. Patch dynamics is
designed to perform numerical simulations of an unavailable macroscopic
equation on macroscopic time and length scales; it uses appropriately
initialized simulations of the available microscopic model in a number of small
boxes (patches), which cover only a fraction of the space-time domain. To
reduce the effect of the artificially introduced box boundaries, we use buffer
regions to "shield" the boundary artefacts from the interior of the domain for
short time intervals. We analyze the accuracy of this scheme for a diffusion
homogenization problem with periodic heterogeneity, and propose a simple
heuristic to determine a sufficient buffer size. The algorithm performance is
illustrated through a set of numerical examples, which include a non-linear
reaction-diffusion equation and the Kuramoto--Sivashinsky equation.


title:
First observation of the acceleration of a single bunch by using the
  induction device in the KEK Proton Synchrotron

abstract:
  A single RF bunch in the KEK proton synchrotron was accelerated with an
induction acceleration method from the injection energy of 500 MeV to 5 GeV.


title:
Fine structure of histograms of alpha-activity measurements depends on
  direction of alpha particles flow and the Earth rotation: experiments with
  collimators

abstract:
  The fine structure of histograms of measurements of 239Pu alpha-activity
varies periodically, and the period of these variations is equal to sidereal
day (1436 minutes). The periodicity is not observed in the experiments with
collimator that restricts the alpha particles flow to be oriented to the Polar
Star. Based on this study and other independent data, such as measurements
conducted by the Arctic expedition, and similarity of the histograms in
processes observed at different locations at the same local time, the
conclusion was made, that the fine structure of statistical distributions of
the observed processes depends on the celestial sphere.


title: On the Conductivity of a Magnetoactive Turbulent Plasma

abstract:
  The problem of determining the effective conductivity tensor of a
magnetoactive turbulent plasma is considered in the approximation of isolated
particles. Additional gyrotropicterms are shown to appear in the conductivity
tensor in the presence of mean, nonzero magnetic helicity. The dispersion of
propagating electro- magnetic waves changes, additional modes and additional
rotation of the polarization plane appear, and the waves can be amplified. The
properties acquired by plasma with helicity are similar those observed in
chiral and bianisotropic electrodynamic media.


title: Bistable diode action in left-handed periodic structures

abstract:
  We study nonlinear transmission of an asymmetric multilayer structure created
by alternating slabs of two materials with positive and negative refractive
index. We demonstrate that such a structure exhibits passive spatially
nonreciprocal transmission of electromagnetic waves, the analogue of the
electronic diode. We study the properties of this left-handed diode and confirm
its highly nonreciprocal and bistable transmittance by employing direct
simulations.


title: Relativity principles in 1+1 dimensions and differential aging reversal

abstract:
  We study the behavior of clocks in 1+1 spacetime assuming the relativity
principle, the principle of constancy of the speed of light and the clock
hypothesis. These requirements are satisfied by a class of Finslerian theories
parametrized by a real coefficient $\beta$, special relativity being recovered
for $\beta=0$. The effect of differential aging is studied for the different
values of $\beta$. Below the critical values $|\beta| =1/c$ the differential
aging has the usual direction - after a round trip the accelerated observer
returns younger than the twin at rest in the inertial frame - while above the
critical values the differential aging changes sign. The non-relativistic case
is treated by introducing a formal analogy with thermodynamics.


title: Comparison of discharge lamp and laser pumped cesium magnetometers

abstract:
  We have performed a comparison of laser (LsOPM) and lamp (LpOPM) pumped
cesium vapor magnetometers. Although the LsOPM operated 50% above its
shot-noise limit we found an intrinsic sensitivity of 15 fT/\sqrt{Hz} and 25
fT/\sqrt{Hz} for the LsOPM and LpOPM respectively. Two modes of operation,
viz.,the phase-stabilized and the self-oscillating mode were investigated and
found to yield a similar performance. We have compared the performance of the
LsOPM and the LpOPM directly by simultaneous measurements of field fluctuations
of a 2 microtesla magnetic field inside a multilayer magnetic shield and have
used one of the magnetometers for an active field stabilization. In the
stabilized mode we found a gradient instability of 25 fT within an integration
time of 100 s, which represents an upper limit of the long-term stability of
the magnetometers.


title: Extracting Work From A Single Heat Bath

abstract:
  We present here a machine that is capable of extracting work from a single
heat bath. Although no significant temperature gradient is involved in the
operation of the machine, yet the Carnot efficiency as high as one is
achievable. Working of the machine is explained on the basis of a demon
suggested by Maxwell. Utilizing the kinetic energy spectrum of the molecules in
solution, the demon can send "hotter" molecules to a higher gravitational
potential at the expense of their own energies. Difference in chemical
potentials due to concentration gradients and use of semi-permeable membranes
ensure the continuing cyclic process.


title:
Accurate electronic excitations for two alkali-halide systems obtained
  by density-functional theory and verified by multi-configuration
  self-consistent field calculations

abstract:
  Use of density-functional theory in a $\Delta$self-consistent field framework
result in both the ground- and two lowest electronicly excited states of the
NaCl and LiCl. The accuracy of this method is confirmed using a
multi-configuration self-consistent field method to obtain the same states. The
overall good agreement between the calculated ground and excited
potential-energy surfaces speaks promising for the computationally simple
$\Delta$self-consistent field method.


title:
The scaling properties of dissipation in incompressible isotropic
  three-dimensional magnetohydrodynamic turbulence

abstract:
  The statistical properties of the dissipation process constrain the analysis
of large scale numerical simulations of three dimensional incompressible
magnetohydrodynamic (MHD) turbulence, such as those of Biskamp and Muller
[Phys. Plasmas 7, 4889 (2000)]. The structure functions of the turbulent flow
are expected to display statistical self-similarity, but the relatively low
Reynolds numbers attainable by direct numerical simulation, combined with the
finite size of the system, make this difficult to measure directly. However, it
is known that extended self-similarity, which constrains the ratio of scaling
exponents of structure functions of different orders, is well satisfied. This
implies the extension of physical scaling arguments beyond the inertial range
into the dissipation range. The present work focuses on the scaling properties
of the dissipation process itself. This provides an important consistency check
in that we find that the ratio of dissipation structure function exponents is
that predicted by the She and Leveque [Phys. Rev. Lett 72, 336 (1994)] theory
proposed by Biskamp and Muller. This supplies further evidence that the cascade
mechanism in three dimensional MHD turbulence is non-linear random eddy
scrambling, with the level of intermittency determined by dissipation through
the formation of current sheets.


title:
Reexamination of Hagen-Poiseuille flow: shape-dependence of the
  hydraulic resistance in microchannels

abstract:
  We consider pressure-driven, steady state Poiseuille flow in straight
channels with various cross-sectional shapes: elliptic, rectangular,
triangular, and harmonic-perturbed circles. A given shape is characterized by
its perimeter P and area A which are combined into the dimensionless
compactness number C = P^2/A, while the hydraulic resistance is characterized
by the well-known dimensionless geometrical correction factor alpha. We find
that alpha depends linearly on C, which points out C as a single dimensionless
measure characterizing flow properties as well as the strength and
effectiveness of surface-related phenomena central to lab-on-a-chip
applications. This measure also provides a simple way to evaluate the hydraulic
resistance for the various shapes.


title: Discrete Momentum Mechanics and Faster Than Light Transition

abstract:
  In this work a new mechanics will be studied which is based on the hypothesis
that the change of linear momentum of a particle happens as a discrete pulses.
By using this hypothesis and by considering Newton's relation between energy
and momentum, and the law of mass and energy conservation as a priori, the
Einstein dispersion relation can be derived as a zero approximation without
using Lorentz transformations. Other terms will be derived as a corrections to
this relation. It will be shown that the effect of the corrections will be
smaller and smaller with the increase of momentum. The work will offer an
explanation of why the velocity of light seems to be constant regardless of the
velocity of the source, and under which condition this will be changed. Also a
prediction is made that faster than light transition could happen theoretically
under certain conditions, and a nonzero mass photon can exist in nature. The
work is purely classical in the sense that it doesn't involve any uncertainty
relations.


title:
Measurement of the parity violating 6S-7S transition amplitude in cesium
  achieved within 2 \times 10^{-13} atomic-unit accuracy by stimulated-emission
  detection

abstract:
  We exploit the process of asymmetry amplification by stimulated emission
which provides an original method for parity violation (PV) measurements in a
highly forbidden atomic transition. The method involves measurements of a
chiral, transient, optical gain of a cesium vapor on the 7S-6P_{3/2}
transition, probed after it is excited by an intense, linearly polarized,
collinear laser, tuned to resonance for one hyperfine line of the forbidden
6S-7S transition in a longitudinal electric field. We report here a 3.5 fold
increase, of the one-second-measurement sensitivity, and subsequent reduction
by a factor of 3.5 of the statistical accuracy compared with our previous
result [J. Gu\'ena et al., Phys. Rev. Lett. 90, 143001 (2003)]. Decisive
improvements to the set-up include an increased repetition rate, better
extinction of the probe beam at the end of the probe pulse and, for the first
time to our knowledge, the following: a polarization-tilt magnifier,
quasi-suppression of beam reflections at the cell windows, and a Cs cell with
electrically conductive windows. We also present real-time tests of systematic
effects, consistency checks on the data, as well as a 1% accurate measurement
of the electric field seen by the atoms, from atomic signals. PV measurements
performed in seven different vapor cells agree within the statistical error.
Our present result is compatible with the more precise Boulder result within
our present relative statistical accuracy of 2.6%, corresponding to a 2 \times
10^{-13} atomic-unit uncertainty in E_1^{pv}. Theoretical motivations for
further measurements are emphasized and we give a brief overview of a recent
proposal that would allow the uncertainty to be reduced to the 0.1% level by
creating conditions where asymmetry amplification is much greater.


title:
Coherent resonant interactions and slow light with molecules confined in
  photonic band-gap fibers

abstract:
  We investigate resonant nonlinear optical interactions and demonstrate
induced transparency in acetylene molecules in a hollow-core photonic band-gap
fiber at 1.5$\mu$m. The induced spectral transmission window is used to
demonstrate slow-light effects, and we show that the observed broadening of the
spectral features is due to collisions of the molecules with the inner walls of
the fiber core. Our results illustrate that such fibers can be used to
facilitate strong coherent light-matter interactions even when the optical
response of the individual molecules is weak.


title: Two-loop calculation of the turbulent Prandtl number

abstract:
  The turbulent Prandtl number has been calculated in the two-loop
approximation of the $\eps$ expansion of the stochastic theory of turbulence.
The strikingly small value obtained for the two-loop correction explains the
good agreement of the earlier one-loop result with the experiment. This
situation is drastically different from other available nontrivial two-loop
results, which exhibit corrections of the magnitude of the one-loop term. The
reason is traced to the mutual cancellation of additional divergences appearing
in two dimensions which have had a major effect on the results of previous
calculations of other quantities.


title: Small clusters of fermions

abstract:
  By comparing respectively the interaction between 3He atoms and the
neutron-neutron one, we examine the possibility for both fermionic systems to
form small clusters.


title:
Chaos and localization in the wavefunctions of complex atoms NdI, PmI
  and SmI

abstract:
  Wavefunctions of complex lanthanide atoms NdI, PmI and SmI, obtained via
multi-configuration Dirac-Fock method, are analyzed for density of states in
terms of partial densities, strength functions ($F_k(E)$), number of principal
components ($\xi_2(E)$) and occupancies ($\lan n_\alpha \ran^E$) of single
particle orbits using embedded Gaussian orthogonal ensemble of one plus
two-body random matrix ensembles [EGOE(1+2)]. It is seen that density of states
are in general multi-modal, $F_k(E)$'s exhibit variations as function of the
basis states energy and $\xi_2(E)$'s show structures arising from localized
states. The sources of these departures from EGOE(1+2) are investigated by
examining the partial densities, correlations between $F_k(E)$, $\xi_2(E)$ and
$\lan n_\alpha \ran^E$ and also by studying the structure of the Hamiltonian
matrices. These studies point out the operation of EGOE(1+2) but at the same
time suggest that weak admixing between well separated configurations should be
incorporated into EGOE(1+2) for more quantitative description of chaos and
localization in NdI, PmI and SmI.


title: Stability of the hydrogen atom of classical electrodynamics

abstract:
  We study the stability of the circular orbits of the electromagnetic two-body
problem of classical electrodynamics. We introduce the concept of resonant
dissipation, i.e. a motion that radiates the center-of-mass energy while the
interparticle distance performs bounded oscillations about a metastable orbit.
The stability mechanism is established by the existence of a quartic resonant
constant generated by the stiff eigenvalues of the linear stability problem.
This constant bounds the particles together during the radiative recoil. The
condition of resonant dissipation predicts angular momenta for the metastable
orbits in reasonable agreement with the Bohr atom. The principal result is that
the emission lines agree with the predictions of quantum electrodynamics (QED)
with 1 percent average error even up to the $40^{th}$ line. Our angular momenta
depend logarithmically on the mass of the heavy body, such that the deuterium
and the muonium atoms have essentially the same angular momenta, in agreement
with QED. Analogously to QED, our stability analysis naturally uses the
eigenvalues of an infinite-dimensional linear operator; the
infinite-dimensionality is brought in by the delay of the electromagnetic
interaction.


title:
Melting and evaporation transitions in small Al clusters: canonical
  Monte-Carlo simulations

abstract:
  A dimer of bound atoms cannot melt, only dissociate. Bulk metals show a well
defined first order transition between their solid and liquid phases. The
appearance of the melting transition is explored for increasing clusters sizes
via the signatures in the specific heat and the root mean square of the bond
lengths $\delta_{\rm B}$ (Berry parameter) by means of Monte-Carlo simulations
of Al clusters modelled by Gupta potentials. Clear signatures of a melting
transition appear for $N\sim 6$ atoms. Closed-shell effects are shown for
clusters with up to 56 atoms. The melting transition is compared in detail with
the dissociation transition, which induces a second and possibly much larger
local maximum in the specific heat at higher temperatures. Larger clusters are
shown to fragment into dimers and trimers, which in turn dissociate at higher
temperatures.


title: The Minkowski metric in non-inertial observer radar coordinates

abstract:
  We give a closed expression for the Minkowski (1+1)-dimensional metric in the
radar coordinates of an arbitrary non-inertial observer O in terms of O's
proper acceleration. Knowledge of the metric allows the non-inertial observer
to perform experiments in spacetime without making reference to inertial
frames. To clarify the relation between inertial and non-inertial observers the
coordinate transformation between radar and inertial coordinates, also is
given. We show that every conformally flat coordinate system can be regarded as
the radar coordinate system of a suitable observer for a suitable
parametrization of the observer worldline. Therefore, the coordinate
transformation between arbitrarily moving observers is a conformal
transformation and conformally invariant (1+1)-dimensional theories lead to the
same physics for all observers, independently of their relative motion.


title:
Numerical solutions of the three-dimensional magnetohydrodynamic
  alpha-model

abstract:
  We present direct numerical simulations and alpha-model simulations of four
familiar three-dimensional magnetohydrodynamic (MHD) turbulence effects:
selective decay, dynamic alignment, inverse cascade of magnetic helicity, and
the helical dynamo effect. The MHD alpha-model is shown to capture the
long-wavelength spectra in all these problems, allowing for a significant
reduction of computer time and memory at the same kinetic and magnetic Reynolds
numbers. In the helical dynamo, not only does the alpha-model correctly
reproduce the growth rate of magnetic energy during the kinematic regime, but
it also captures the nonlinear saturation level and the late generation of a
large scale magnetic field by the helical turbulence.


title: Endogenous versus Exogenous Origins of Crises

abstract:
  Are large biological extinctions such as the Cretaceous/Tertiary KT boundary
due to a meteorite, extreme volcanic activity or self-organized critical
extinction cascades? Are commercial successes due to a progressive reputation
cascade or the result of a well orchestrated advertisement? Determining the
chain of causality for extreme events in complex systems requires disentangling
interwoven exogenous and endogenous contributions with either no clear or too
many signatures. Here, I review several efforts carried out with collaborators,
which suggest a general strategy for understanding the organization of several
complex systems under the dual effect of endogenous and exogenous fluctuations.
The studied examples are: Internet download shocks, book sale shocks, social
shocks, financial volatility shocks, and financial crashes. Simple models are
offered to quantitatively relate the endogenous organization to the exogenous
response of the system. Suggestions for applications of these ideas to many
other systems are offered.


title:
Nonlinear Dynamical Behaviors of the Equilibrium Longitudinal
  Distribution by Localized Wakes in an Electron Storage Ring

abstract:
  We investigate the effects of a localized constant wake and a localized
linear wake on the longitudinal beam distribution in equilibrium. We also
examine the effects of the composite wake on the particle distribution when the
constant wake and linear wake simultaneously exist in the ring. While moving
around the parameter space, the system can show bifurcation phenomena and
transition features between periodic states. We study the dynamical states in a
beam, using the multi-particle tracking method in a Gaussian approximation.
They show good qualitative agreement.


title:
The Unique Determination of Neuronal Currents in the Brain via
  Magnetoencephalography

abstract:
  The problem of determining the neuronal current inside the brain from
measurements of the induced magnetic field outside the head is discussed under
the assumption that the space occupied by the brain is approximately spherical.
By inverting the Geselowitz equation, the part of the current which can be
reconstructed from the measurements is precisely determined. This actually
consists of only certain moments of one of the two functions specifying the
tangential part of the current. The other function specifying the tangential
part of the current as well as the radial part of the current are completely
arbitrary. However, it is also shown that with the assumption of energy
minimization, the current can be reconstructed uniquely. A numerical
implementation of this unique reconstruction is also presented.


title: Spectral Mixture Decomposition by Least Dependent Component Analysis

abstract:
  A recently proposed mutual information based algorithm for decomposing data
into least dependent components (MILCA) is applied to spectral analysis, namely
to blind recovery of concentrations and pure spectra from their linear
mixtures. The algorithm is based on precise estimates of mutual information
between measured spectra, which allows to assess and make use of actual
statistical dependencies between them. We show that linear filtering performed
by taking second derivatives effectively reduces the dependencies caused by
overlapping spectral bands and, thereby, assists resolving pure spectra. In
combination with second derivative preprocessing and alternating least squares
postprocessing, MILCA shows decomposition performance comparable with or
superior to specialized chemometrics algorithms. The results are illustrated on
a number of simulated and experimental (infrared and Raman) mixture problems,
including spectroscopy of complex biological materials.
  MILCA is available online at http://www.fz-juelich.de/nic/cs/software

categories: physics.data-an cs.IT math.IT physics.chem-ph


title:
Reconstruction Algorithms for Positron Emission Tomography and Single
  Photon Emission Computed Tomography and their Numerical Implementation

abstract:
  The modern imaging techniques of Positron Emission Tomography and of Single
Photon Emission Computed Tomography are not only two of the most important
tools for studying the functional characteristics of the brain, but they now
also play a vital role in several areas of clinical medicine, including
neurology, oncology and cardiology. The basic mathematical problems associated
with these techniques are the construction of the inverse of the Radon
transform and of the inverse of the so called attenuated Radon transform
respectively. We first show that, by employing mathematical techniques
developed in the theory of nonlinear integrable equations, it is possible to
obtain analytic formulas for these two inverse transforms. We then present
algorithms for the numerical implementation of these analytic formulas, based
on approximating the given data in terms of cubic splines. Several numerical
tests are presented which suggest that our algorithms are capable of producing
accurate reconstruction for realistic phantoms such as the well known
Shepp--Logan phantom.


title:
Niobium Quarter-Wave Resonator Development for The Rare Isotope
  Accelerator

abstract:
  Two superconducting quarter-wave resonator (QWR) prototypes have been
fabricated and tested. They operate at 80.5 MHz and 161 MHz and are optimised
for beta = 0.085 and beta = 0.16, respectively. The prototypes are simplified
versions without integrated helium vessels. In the first RF tests, the beta =
0.085 QWR reached a peak surface electric field (Ep) in excess of 30 MV/m, with
an intrinsic quality factor (Q0) in excess of 1E9 at the design field of Ep =
20 MV/m. The beta = 0.16 QWR reached Ep = 20 MV/m with Q0 = 2.5E9. It is
suspected that the performance of the latter cavity can be improved via better
cooling of the Nb tuning plate and a better RF contact between the plate and
the outer conductor.


title: Is the Dirac particle completely relativistic?

abstract:
  The Dirac particle, i.e. the dynamic system S_D, described by the free Dirac
equation is investigated. Although the Dirac equation is written usually in the
relativistically covariant form, the dynamic system S_D is not completely
relativistic, because its description contains such absolute objects as $\gamma
$-matrices $\gamma ^{k}$, forming a matrix vector. By means of the proper
change of variables the $\gamma $-matrices are eliminated, but instead of them
the constant timlike vector $f^{k}$ appears. The vector $f^{k}$ describes an
absolute splitting of the space-time into space and time, which is
characteristic for the nonrelativistic description. To investigate a degree of
the violation of the S_D relativistic description, we consider the classical
Dirac particle S_{Dcl}, obtained from S_D by means of the relativistic dynamic
disquantization. The classical dynamic system S_{Dcl} appears to be composite,
because it has ten degrees of freedom. Six translational degrees of freedom are
described relativistically (without a reference to $f^{k}$), whereas four
internal degrees of freedom are described nonrelativistically, because their
description refers to $f^{k}$. Coupling the absolute vector $f^{k}$ with the
energy-momentum vector of S_{Dcl}, the classical Dirac particle S_{Dcl} is
modified minimally. The vector $f^{k}$ ceases to be absolute, and the modified
classical Dirac particle S_{mDcl} becomes to be completely relativistic. The
dynamic equations for S_{mDcl} are solved. Solutions for S_{Dcl} and S_{mDcl}
are compared.


title: Free-energy model for fluid helium at high density

abstract:
  We present a semi-analytical free-energy model aimed at characterizing the
thermodynamic properties of dense fluid helium, from the low-density atomic
phase to the high-density fully ionized regime. The model is based on a
free-energy minimization method and includes various different contributions
representative of the correlations between atomic and ionic species and
electrons. This model allows the computation of the thermodynamic properties of
dense helium over an extended range of density and temperature and leads to the
computation of the phase diagram of dense fluid helium, with its various
temperature and pressure ionization contours. One of the predictions of the
model is that pressure ionization occurs abruptly at $\rho \simgr 10$ g
cm$^{-3}$, {\it i.e.} $P\simgr 20$ Mbar, from atomic helium He to fully ionized
helium He$^{2+}$, or at least to a strongly ionized state, without He$^{+}$
stage, except at high enough temperature for temperature ionization to become
dominant. These predictions and this phase diagram provide a guide for future
dynamical experiments or numerical first-principle calculations aimed at
studying the properties of helium at very high density, in particular its
metallization. Indeed, the characterization of the helium phase diagram bears
important consequences for the thermodynamic, magnetic and transport properties
of cool and dense astrophysical objects, among which the solar and the numerous
recently discovered extrasolar giant planets.

categories: physics.plasm-ph astro-ph cond-mat.other physics.gen-ph


title: Composite vortex-ring solitons in Bessel photonic lattices

abstract:
  We reveal the existence of dynamically stable composite topological solitons
in Bessel photonic lattices imprinted in focusing Kerr-type nonlinear media.
The new stable composite solitons are made of a vortex-ring with unit
topological charge incoherently coupled to a fundamental soliton. The
stabilization of the otherwise highly azimuthally unstable vortex-rings is
provided under suitable conditions, which we study in detail, by
cross-phase-modulation coupling with the fundamental soliton companion.


title: Stable ring vortex solitons in Bessel optical lattices

abstract:
  Stable ring vortex solitons, featuring a bright-shape, appear to be very rare
in nature. However, here we show that they exist and can be made dynamically
stable in defocusing cubic nonlinear media with an imprinted Bessel optical
lattice. We find the families of vortex lattice solitons and reveal their
salient properties, including the conditions required for their stability. We
show that the higher the soliton topological charge, the deeper the lattice
modulation necessary for stabilization.


title: Extraction of electric field in heavily irradiated silicon pixel sensors

abstract:
  A new method for the extraction of the electric field in the bulk of heavily
irradiated silicon pixel sensors is presented. It is based on the measurement
of the Lorentz deflection and mobility of electrons as a function of depth. The
measurements were made at the CERN H2 beam line, with the beam at a shallow
angle with respect to the pixel sensor surface. The extracted electric field is
used to simulate the charge collection and the Lorentz deflection in the pixel
sensor. The simulated charge collection and the Lorentz deflection is in good
agreement with the measurements both for non-irradiated and irradiated up to
1E15 neq/cm2 sensors.


title:
Noise-Induced Transition from Translational to Rotational Motion of
  Swarms

abstract:
  We consider a model of active Brownian agents interacting via a harmonic
attractive potential in a two-dimensional system in the presence of noise. By
numerical simulations, we show that this model possesses a noise-induced
transition characterized by the breakdown of translational motion and the onset
of swarm rotation as the noise intensity is increased. Statistical properties
of swarm dynamics in the weak noise limit are further analytically
investigated.


title: Unipolar components travelling at the speed of light in vacuo

abstract:
  We describe a physical situation where the time integral of the electric
field of an electromagnetic wave packet is not zero. More specifically, the
non-oscillating component of the Fourier spectrum, i.e. the component resulting
from the Fourier transform of the electric field evaluated at $\omega=0$, can
be associated with the area under a locally unipolar electromagnetic pulse that
travels in free space at the speed of light.


title: The Einstein Postulates: 1905-2005 A Critical Review of the Evidence

abstract:
  The Einstein postulates assert an invariance of the propagation speed of
light in vacuum for any observer, and which amounts to a presumed absence of
any preferred frame. The postulates appear to be directly linked to
relativistic effects which emerge from Einstein's Special Theory of Relativity,
which is based upon the concept of a flat spacetime ontology, and which then
lead to the General Theory of Relativity with its curved spacetime model for
gravity. While the relativistic effects are well established experimentally it
is now known that numerous experiments, beginning with the Michelson-Morley
experiment of 1887, have always shown that the postulates themselves are false,
namely that there is a detectable local preferred frame of reference. This
critique briefly reviews the experimental evidence regarding the failure of the
postulates, and the implications for our understanding of fundamental physics,
and in particular for our understanding of gravity. A new theory of gravity is
seen to be necessary, and this results in an explanation of the `dark matter'
effect entailing the discovery that the fine structure constant is a 2nd
gravitational constant.


title:
Projection of relativistically moving objects on a two-dimensional
  plane, the `train' paradox and the visibility of the Lorentz contraction

abstract:
  Although many papers have appeared on the theory of photographing
relativistically moving objects, pioneered by the classic work of Penrose and
Terrell, three problems remain outstanding. (1) There does not seem to exist a
general formula which gives the projection of a relativistically moving object,
applicable to any object no matter how complicated, on a two-dimensional plane
in conformity with Terrell's observation. (2) No resolution seems to have been
provided for the associated so-called `train' paradox. (3) No analytical
demonstration seems to have been offered on how the Lorentz contraction may be
actually detected on a photograph. This paper addresses all of these three
problems. The analysis does not require any more than trigonometry and
elementary differentiation.


title:
Relativistic quantum dynamics in strong fields: Photon emission from
  heavy, few-electron ions

abstract:
  Recent progress in the study of the photon emission from highly-charged heavy
ions is reviewed. These investigations show that high-$Z$ ions provide a unique
tool for improving the understanding of the electron-electron and
electron-photon interaction in the presence of strong fields. Apart from the
bound-state transitions, which are accurately described in the framework of
Quantum Electrodynamics, much information has been obtained also from the
radiative capture of (quasi-) free electrons by high-$Z$ ions. Many features in
the observed spectra hereby confirm the inherently relativistic behavior of
even the simplest compound quantum systems in Nature.


title:
Demonstration of ultra-high-Q small mode volume toroid microcavities on
  a chip

abstract:
  Optical microcavities confine light spatially and temporally and find
application in a wide range of fundamental and applied studies. In many areas,
the microcavity figure of merit is not only determined by photon lifetime (or
the equivalent quality-factor, Q), but also by simultaneous achievement of
small mode volume V . Here we demonstrate ultra-high Q-factor small mode volume
toroid microcavities on-a-chip, which exhibit a Q/V factor of more than
$10^{6}(\lambda/n)^{-3}$. These values are the highest reported to date for any
chip-based microcavity. A corresponding Purcell factor in excess of 200 000 and
a cavity finesse of $2.8\times10^{6}$ is achieved, demonstrating that toroid
microcavities are promising candidates for studies of the Purcell effect,
cavity QED or biochemical sensing


title: Power law distribution of seismic rates: theory and data

abstract:
  We report an empirical determination of the probability density functions
P(r) of the number r of earthquakes in finite space-time windows for the
California catalog, over fixed spatial boxes 5 x 5 km^2 and time intervals dt
=1, 10, 100 and 1000 days. We find a stable power law tail P(r) ~ 1/r^{1+mu}
with exponent mu \approx 1.6 for all time intervals. These observations are
explained by a simple stochastic branching process previously studied by many
authors, the ETAS (epidemic-type aftershock sequence) model which assumes that
each earthquake can trigger other earthquakes (``aftershocks''). An aftershock
sequence results in this model from the cascade of aftershocks of each past
earthquake. We develop the full theory in terms of generating functions for
describing the space-time organization of earthquake sequences and develop
several approximations to solve the equations. The calibration of the theory to
the empirical observations shows that it is essential to augment the ETAS model
by taking account of the pre-existing frozen heterogeneity of spontaneous
earthquake sources. This seems natural in view of the complex multi-scale
nature of fault networks, on which earthquakes nucleate. Our extended theory is
able to account for the empirical observation satisfactorily. In particular,
the adjustable parameters are determined by fitting the largest time window
$dt=1000$ days and are then used as frozen in the formulas for other time
scales, with very good agreement with the empirical data.


title:
Genesis of Dark Energy: Dark Energy as a Consequence of Cosmological
  Nuclear Energy

abstract:
  Recent observations on Type-Ia supernovae and low density measurement of
matter (including dark matter) suggest that the present day universe consists
mainly of repulsive-gravity type exotic-matter with negative-pressure often
referred as dark-energy. But the mystery is about the nature of dark-energy and
its puzzling questions such as why, how, where & when about the dark- energy
are intriguing. In the present paper the author attempts to answer these
questions while making an effort to reveal the genesis of dark-energy, and
suggests that the cosmological nuclear-binding-energy liberated during
primordial nucleo-synthesis remains trapped for long time and then is released
free which manifests itself as dark-energy in the universe. It is also
explained why for dark energy the parameter w = -2/3. Noting that w=+1for stiff
matter and w=+1/3 for radiation; w = - 2/3 is for dark energy, because -1 is
due to deficiency of stiff-nuclear-matter and that this binding energy is
ultimately released as radiation contributing +1/3, making w = -1 + 1/3 = -2/3.
This thus almost solves the dark-energy mystery of negative-pressure &
repulsive-gravity. It is concluded that dark-energy is a consequence of
released-free nuclear-energy of cosmos. The proposed theory makes several
estimates / predictions, which agree reasonably well with the astrophysical
constraints & observations.


title: Propagation of the main signal in a dispersive Lorentz medium

abstract:
  Evolution of the main signal in a Lorentz dispersive medium is considered.
The signal propagating in the medium is excited by a sine-modulated pulse
signal, with its envelope described by a hyperbolic tangent function. Both
uniform and non-uniform asymptotic representations for the signal are found. It
is shown when the uniform representation can be reduced to the non-uniform one.
The results obtained are illustrated with a numerical example.


title: Nonlinear Evolution of q=1 Triple Tearing Modes in a Tokamak Plasma

abstract:
  In magnetic configurations with two or three q=1 (with q being the safety
factor) resonant surfaces in a tokamak plasma, resistive magnetohydrodynamic
modes with poloidal mode numbers m much larger than 1 are found to be linearly
unstable. It is found that these high-m double or triple tearing modes
significantly enhance through nonlinear interactions, the growth of the m=1
mode. This may account for the sudden onset of the internal resistive kink,
i.e., the fast sawtooth trigger. Based on the subsequent reconnection dynamics
that can proceed without formation of the m=1 islands, it is proposed that
high-m triple tearing modes are a possible mechanism for precursor-free partial
collapses during sawtooth oscillations.


title: Whistleron Gas in Magnetized Plasmas

abstract:
  We have studied the nonlinear dynamics of whistler waves in magnetized
plasmas. Since plasmas and beam-plasma systems considered here are assumed to
be weakly collisional, the point of reference for the analysis performed in the
present paper is the system of hydrodynamic and field equations. We have
applied the renormalization group method to obtain dynamical equations for the
slowly varying amplitudes of whistler waves. Further, it has been shown that
the amplitudes of eigenmodes satisfy an infinite system of coupled nonlinear
Schr\"{o}dinger equations. In this sense, the whistler eigenmodes form a sort
of a gas of interacting quasiparticles, while the slowly varying amplitudes can
be considered as dynamical variables heralding the relevant information about
the system. An important feature of our description is that whistler waves do
not perturb the initial uniform density of plasma electrons. The plasma
response to the induced whistler waves consists in velocity redistribution
which follows exactly the behaviour of the whistlers. In addition, selection
rules governing the nonlinear mode coupling have been derived, which represent
another interesting peculiarity of our description.


title:
Zero-Temperature Theory of Collisionless Rapid Adiabatic Passage from a
  Fermi Degenerate Gas of Atoms to a Bose-Einstein Condensate of Molecules

abstract:
  We theoretically examine a zero-temperature system of Fermi degenerate atoms
coupled to bosonic molecules via collisionless rapid adiabatic passage across a
Feshbach resonance, focusing on saturation of the molecular conversion
efficiency at the slowest magnetic-field sweep rates. Borrowing a novel
MANY-FERMION Fock-state theory, we find that a proper model of the
magnetic-field sweep can systematically remove saturation. We also debunk the
common misconception that many-body effects are responsible for molecules
existing above the two-body threshold.

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


title:
Dependence of the Brillouin precursor form on the initial signal rise
  time

abstract:
  Propagation of a Brillouin precursor in a Lorentz dispersive medium is
considered. The precursor is excited by a sine modulated initial signal, with
its envelope described by a hyperbolic tangent function. The purpose of the
paper is to show how the rate of growth of the initial signal affects the form
of the Brillouin precursor. Uniform asymptotic approach, pertinent to
coalescing saddle points, is applied in the analysis. The results are
illustrated with numerical examples.


title: Power Law Distributions of Seismic Rates

abstract:
  We report an empirical determination of the probability density functions
$P_{\text{data}}(r)$ of the number $r$ of earthquakes in finite space-time
windows for the California catalog. We find a stable power law tail
$P_{\text{data}}(r) \sim 1/r^{1+\mu}$ with exponent $\mu \approx 1.6$ for all
space ($5 \times 5$ to $20 \times 20$ km$^2$) and time intervals (0.1 to 1000
days). These observations, as well as the non-universal dependence on
space-time windows for all different space-time windows simultaneously, are
explained by solving one of the most used reference model in seismology (ETAS),
which assumes that each earthquake can trigger other earthquakes. The data
imposes that active seismic regions are Cauchy-like fractals, whose exponent
$\delta =0.1 \pm 0.1$ is well-constrained by the seismic rate data.


title:
Complex light: Dynamic phase transitions of a light beam in a nonlinear
  non-local disordered medium

abstract:
  The dynamics of several light filaments (spatial optical solitons)
propagating in an optically nonlinear and non-local random medium is
investigated using the paradigms of the physics of complexity. Cluster
formation is interpreted as a dynamic phase transition. A connection with the
random matrices approach for explaining the vibrational spectra of an ensemble
of solitons is pointed out. General arguments based on a Brownian dynamics
model are validated by the numerical simulation of a stochastic partial
differential equation system. The results are also relevant for Bose condensed
gases and plasma physics.


title:
Equilibrium Configurations of the Charged Surface of a Conducting Liquid
  at a Finite Interelectrode Distance

abstract:
  The problem of determining equilibrium configurations of the free surface of
a conducting liquid is considered with allowance for a finite interelectrode
distance. The analogy is established between this electrostatic problem and
that of finding the profile of a progressive capillary wave on the free surface
of a liquid layer of a finite depth, which was solved by Kinnersley. This
analogy allowed exact solutions to be obtained for the geometry of liquid
electrodes, which expand the existing notions about the possible stationary
states of the system.


title: Sympathetic cooling of $^4$He$^+$ ions in a radiofrequency trap

abstract:
  We have generated Coulomb crystals of ultracold $^4$He$^+$ ions in a linear
radiofrequency trap, by sympathetic cooling via laser--cooled $^9$Be$^+$.
Stable crystals containing up to 150 localized He$^+$ ions at $\sim$20 mK were
obtained. Ensembles or single ultracold He$^+$ ions open up interesting
perspectives for performing precision tests of QED and measurements of nuclear
radii. The present work also indicates the feasibility of cooling and
crystallizing highly charged atomic ions using $^9$Be$^+$ as coolant.


title: Ellipsoidal Coulomb Crystals in a Linear Radiofrequency Trap

abstract:
  A static quadrupole potential breaks the cylindrical symmetry of the
effective potential of a linear rf trap. For a one-component fluid plasma at
low temperature, the resulting equilibrium charge distribution is predicted to
be an ellipsoid. We have produced laser-cooled Be$^+$ ellipsoidal ion crystals
and found good agreement between their shapes and the cold fluid prediction. In
two-species mixtures, containing Be$^+$ and sympathetically cooled ions of
lower mass, a sufficiently strong static quadrupole potential produces a
spatial separation of the species.


title: Arago (1810): the first experimental result against the ether

abstract:
  95 years before Special Relativity was born, Arago attempted to detect the
absolute motion of the Earth by measuring the deflection of starlight passing
through a prism fixed to the Earth. The null result of this experiment gave
rise to the Fresnel's hypothesis of an ether partly dragged by a moving
substance. In the context of Einstein's Relativity, the sole frame which is
privileged in Arago's experiment is the proper frame of the prism, and the null
result only says that Snell's law is valid in that frame. We revisit the
history of this premature first evidence against the ether theory and calculate
the Fresnel's dragging coefficient by applying the Huygens' construction in the
frame of the prism. We expose the dissimilar treatment received by the ray and
the wave front as an unavoidable consequence of the classical notions of space
and time.


title: Zirconium oxidation under high energy heavy ion irradiation

abstract:
  This paper concerns the study of zirconium oxidation under irradiation with
high energetic Xe ions. The irradiations were performed on the IRRSUD beam line
at GANIL (Caen). The oxygen partial pressure was fixed at 10$^{-3}$ Pa and two
temperature conditions were used, either 480$\circ$C reached by Joule effect
heating or 280$\circ$C due to Xe energy deposition. Zirconia was fully
characterized by Rutherford Backscattering Spectrometry, Transmission Electron
Microscopy and Grazing Angle X-ray Diffraction. Apparent diffusion coefficients
of oxygen in ZrO2 were determined from these experiments by using a model which
takes into account a surface exchange between oxygen gas and the ZrO2 surface.
These results are compared with thermal oxidation data.


title: Ion backflow in the Micromegas TPC for the future linear collider

abstract:
  We present ion backflow measurements in a Micromegas (MICRO-MEsh GASeous
detector) TPC device developed for the next high energy electron-positron
linear collider under study and a simple explanation for this backflow. A
Micromegas micro-mesh has the intrinsic property to naturally stop a large
fraction of the secondary positive ions created in the avalanche. It is shown
that under some workable conditions on the pitch of the mesh and on the gas
mixture, the ion feedback is equal to the field ratio (ratio of the drift
electric field to the amplification field). Measurements with an intense X-ray
source are in good agreement with calculations and simulations. The conclusion
is that in the electric field conditions foreseen for the Micromegas TPC (drift
and amplification fields respectively equal to 150-200 V/cm and 50-80 kV/cm)
the expected ion backflow will be of the order of $2 - 3 x 10^-3$. In addition,
measurements have been done in a 2T magnetic field: as expected the ion
backflow is not altered by the magnetic field.


title:
Complex Dynamics of Autonomous Communication Networks and the
  Intelligent Communication Paradigm

abstract:
  Dynamics of arbitrary communication system is analysed as unreduced
interaction process. The applied generalised, universally nonperturbative
method of effective potential reveals the phenomenon of dynamic multivaluedness
of competing system configurations forced to permanently replace each other in
a causally random order, which leads to universally defined dynamical chaos,
complexity, fractality, self-organisation, and adaptability (physics/9806002,
physics/0211071, physics/0405063). We demonstrate the origin of huge,
exponentially high efficiency of the unreduced, complex network dynamics and
specify the universal symmetry of complexity (physics/0404006) as the
fundamental guiding principle for creation and control of such qualitatively
new kind of networks and devices. The emerging intelligent communication
paradigm and its practical realisation in the form of knowledge-based networks
involve the features of true, unreduced intelligence and consciousness
(physics/0409140) appearing in complex (multivalued) network dynamics and
results.


title: Why Time is Future Oriented

abstract:
  We assume that the universe consists of clusters which in turns have
sub-clusters and the sub-clusters have sub-subclusters and so on. Confining to
three-dimensional space, it is shown that the universe is expanding if entropy
of the universe increases. It is also shown that clocks slow down when time
progresses towards future. Our model also justifies the big bang theory.


title: On a connection between gravitation and quantum chromodynamics

abstract:
  In this paper we point out a remarkable numerical relation between the large
scale parameters of gravitation G_N and H_0 and the two fundamental parameters
of quantum cromodynamics alpha_{QCD} and Lambda_{QCD}. With this remark we make
the conjecture that Newton's gravitational constant could show an energy
dependence analogous to alpha_{QCD}.