title: Diffraction of light by interfering liquid surface waves

abstract:
  Interfering liquid surface waves are generated by electrically driven
vertical oscillations of two or more equispaced pins immersed in a liquid
(water). The corresponding intensity distribution, resulting from diffraction
of monochromatic light by the reflection phase grating formed on the liquid
surface, is calculated theoretically and found to tally with experiments. The
curious features of the diffraction pattern and its relation to the
interference of waves on the liquid surface are used to measure the amplitude
and wavelength of the resultant surface wave along the line joining the two
sources of oscillation. Finally, a sample diffraction pattern obtained by
optically probing surface regions where interference produces a lattice--like
structure is demonstrated and qualitatively explained.


title: Calculation of reduced coefficients and matrix elements in jj-coupling

abstract:
  A program RCFP will be presented for calculating standard quantities in the
decomposition of many-electron matrix elements in atomic structure theory. The
list of quantities wich are supported by the present program includes the
coefficients of fractional parentage, the reduced coefficients of fractional
parentage, the reduced matrix elements of the unit operator T^{(k)} as well as
the completely reduced matrix elements of the operator W^{(k_jk_q)} in
jj-coupling. These quantities are now available for all subshells (nj) with j
\leq 9/2 including partially filled 9/2-shells. Our program is based on a
recently developed new approach on the spin-angular integration which combines
second quantization and quasispin methods with the theory of angular momentum
in order to obtain a more efficient evaluation of many-electron matrix
elements. An underlying Fortran 90/95 module can directly be used also in
(other) atomic structure codes to accelerate the computation for open-shell
atoms and ions.


title: Program to calculate pure angular momentum coefficients in jj-coupling

abstract:
  A program for computing pure angular momentum coefficients in relativistic
atomic structure for any scalar one- and two-particle operator is presented.
The program, written in Fortran 90/95 and based on techniques of second
quantization, irreducible tensorial operators, quasispin and the theory of
angular momentum, is intended to replace existing angular coefficient modules
from GRASP92. The new module uses a different decomposition of the coefficients
as sums of products of pure angular momentum coefficients, which depend only on
the tensor rank of the interaction but not on its details, with effective
interaction strengths of specific interactions. This saves memory and reduces
the computational cost of big calculations signficantly.


title:
Detecting non-linearities in data sets. Characterization of Fourier
  phase maps using the Weighted Scaling Indices

abstract:
  We present a methodology for detecting non-linearities in data sets based on
the characterization of the structural features of the Fourier phase maps. A
Fourier phase map is a 2D set of points $M= \{(\phi_{\vec{k}}, \phi_{\vec{k} +
\vec{\Delta}})\}$, where $ \phi_{\vec{k}}$ is the phase of the $k$-mode of the
Fourier transform of the data set and $\vec{\Delta}$ a phase shift. The
information thus rendered on this space is analyzed using the spectrum of
weighted scaling indices to detect phase coupling at any scale $\vec{\Delta}$.
We propose a statistical test of significance based on the comparison of the
properties of phase maps created from both the original data and surrogate
realizations. We have applied our method to the Lorenz system and the
logarithmic stock returns of the Dow Jones index. Applications to higher
dimensional data are straightforward. The results indicate that both the Lorenz
system and the Dow Jones time series exhibit significant signatures of
non-linear behavior.


title: The Classical Electron Problem

abstract:
  In this paper, we construct a parallel image of the conventional Maxwell
theory by replacing the observer-time by the proper-time of the source. This
formulation is mathematically, but not physically, equivalent to the
conventional form. The change induces a new symmetry group which is distinct
from, but closely related to the Lorentz group, and fixes the clock of the
source for all observers. The new wave equation contains an additional term
(dissipative), which arises instantaneously with acceleration. This shows that
the origin of radiation reaction is not the action of a "charge" on itself but
arises from inertial resistance to changes in motion. This dissipative term is
equivalent to an effective mass so that classical radiation has both a massless
and a massive part. Hence, at the local level the theory is one of particles
and fields but there is no self-energy divergence (nor any of the other
problems). We also show that, for any closed system of particles, there is a
global inertial frame and unique (invariant) global proper-time (for each
observer) from which to observe the system. This global clock is intrinsically
related to the proper clocks of the individual particles and provides a unique
definition of simultaneity for all events associated with the system. We
suggest that this clock is the historical clock of Horwitz, Piron, and Fanchi.
At this level, the theory is of the action-at-a-distance type and the
absorption hypothesis of Wheeler and Feynman follows from global conservation
of energy.


title:
On determination of electronic-vibro-rotational term values of diatomic
  molecules from measured wavenumbers

abstract:
  A method is proposed for determining rovibronic term values of diatomics from
experimental data on the wavenumbers of electronic-vibro-rotational spectral
lines. In contrast to existing techniques, the new one is based on the
Rydberg-Ritz principle only. It is shown that a link between a set of
rovibronic term values and a set of wavenumbers of observed rovibronic spectral
lines appears when three and more different electronic-vibrational states are
pairwise-connected by radiative transitions. The method differs from known
techniques in several aspects, namely, it: 1) doesn't need any assumptions
concerning an internal structure of a molecule; 2) doesn't involve any
intermediate parameters (as molecular constants in traditional techniques); 3)
gives an opportunity to use in one-stage optimization procedure all available
experimental data obtained for various band systems, by various authors, and in
various works; 4) provides in an interactive mode the opportunity to select the
experimental values, eliminating rough errors, to revise wrong identifications
of spectral lines and to compare various sets of experimental data for mutual
consistency; 5) allows to obtain not only an optimal set of rovibronic term
values, but also the error bars depending on quantity and quality of existing
experimental data. Necessary precondition for use of this method is a
preliminary identification of electronic-vibro-rotational lines to certain
electronic-vibro-rotational radiative transitions. For this purpose one has to
use traditional methods of the analysis of molecular spectra.


title:
Distributions in spherical coordinates with applications to classical
  electrodynamics

abstract:
  A general and rigorous method to deal with singularities at the origin of a
polar coordinate system is presented. Its power derives from a clear
distinction between the radial distance and the radial coordinate variable,
which makes that all delta-functions and their derivatives are automatically
generated, and insures that the Gauss theorem is correct for any distribution
with a finite number of isolated point-like singularities.
  The method is applied to the Coulomb field, and to show the intrinsic
differences between the dipole and dimonopole fields in classical
electrodynamics.
  In all cases the method directly leads to the general expressions required by
the internal consistency of classical electrodynamics.

categories: physics.class-ph math-ph math.MP physics.ed-ph


title:
Folding Trp-cage to NMR resolution native structure using a
  coarse-grained model

abstract:
  We develop a coarse-grained protein model with a simplified amino acid
interaction potential. We perform discrete molecular dynamics folding
simulations of a small 20 residue protein - Trp-cage - from a fully extended
conformation. We demonstrate the ability of the Trp-cage model to consistently
reach conformations within 2angstrom backbone root-mean-square distance (RMSD)
from the corresponding NMR structures. The minimum RMSD of Trp-cage
conformations in the simulation can be smaller than 1.00angstrom. Our findings
suggest that, at least for the case of Trp-cage, a detailed all-atom protein
model with a physical molecular mechanics force field is not necessary to reach
the native state of a protein. Our results also suggest that the success
folding Trp-cage in our simulations and in the reported all-atom molecular
mechanics simulations studies may be mainly due to the special stabilizing
features specific to this miniprotein.

categories: physics.bio-ph cond-mat.other cond-mat.soft cond-mat.stat-mech physics.comp-ph q-bio.OT


title: Random Walks and Effective Resistances on Toroidal and Cylindrical Grids

abstract:
  A mapping between random walk problems and resistor network problems is
described and used to calculate the effective resistance between any two nodes
on an infinite two-dimensional square lattice of unit resistors. The
superposition principle is then used to find effective resistances on toroidal
and cylindrical square lattices.


title:
Pure spin-angular momentum coefficients for non-scalar one-particle
  operators in jj-coupling

abstract:
  A revised program for generating the spin-angular coefficients in
relativistic atomic structure calculations is presented. When compared with our
previous version [G.Gaigalas, S.Fritzsche and I.P.Grant, CPC 139 (2001) 263],
the new version of the Anco program now provides these coefficients for both,
scalar as well as non-scalar one-particle operators as they arise frequently in
the study of transition probabilities, photoionization and electron capture
processes, the alignment transfer through excited atomic states, collision
strengths, and in many other investigations.
  The program is based on a recently developed formalism [G.Gaigalas,
Z.Rudzikas, and C.F.Fischer, J. Phys. B 30 (1997) 3747], which combines
techniques from second quantization in coupled tensorial form, the theory of
quasispin, and the use of reduced coefficients of fractional parentage, in
order to derive the spin-angular coefficients for complex atomic shell
structures more efficiently. By making this approach now available also for
non-scalar interactions, therefore, studies on a whole field of new properties
and processes are likely to become possible even for atoms and ions with a
complex structure.


title: Non-sequential double ionization of molecules

abstract:
  Double ionization of diatomic molecules by short linearly polarized laser
pulses is analyzed. We consider the final stage of the ionization process, that
is the decay of a highly excited two electron molecule, which is formed after
re-scattering. The saddles of the effective adiabatic potential energy close to
which simultaneous escape of electrons takes place are identified. Numerical
simulations of the ionization of molecules show that the process can be
dominated by either sequential or non-sequential events.
  In order to increase the ratio of non-sequential to sequential ionizations
very short laser pulses should be applied.


title:
One-point statistics and intermittency of induced electric field in the
  solar wind

abstract:
  The interplanetary induced electric field e=vxb is studied, using solar wind
time series. The probability distribution functions (PDFs) of the electric
field components are measured from the data and their non-gaussianity is
discussed. Moreover, for the first time we show that the electric field
turbulence is characterized by intermittency. This point is addressed by
studying, as usual, the scaling of the PDFs of field increments, which allows a
quantitative characterization of intermittency.

categories: physics.space-ph astro-ph nlin.CD physics.plasm-ph


title:
Some Comments on the Theory of Bose Condensation, with particular
  reference to the Interiors of Stars

abstract:
  The possibility of the phenomenon of Bose condensation having a part to play
in the discussion of neutron stars has been around for some time. Here the
sorts of temperatures and densities that might be involved are discussed. Also,
an alternative way of viewing the Bose condensation phenomenon is examined once
more and, although found to lead to more accurate results in traditional
examples, is found to have little numerical effect in astrophysical examples.


title: Monte Carlo results for the hydrogen Hugoniot

abstract:
  We propose a theoretical Hugoniot obtained by combining results for the
equation of state (EOS) from the Direct Path Integral Monte Carlo technique
(DPIMC) and those from Reaction Ensemble Monte Carlo (REMC) simulations. The
main idea of such proposal is based on the fact that DPMIC provides
first-principle results for a wide range of densities and temperatures
including the region of partially ionized plasmas. On the other hand, for lower
temperatures where the formation of molecules becomes dominant, DPIMC
simulations become cumbersome and inefficient. For this region it is possible
to use accurate REMC simulations where bound states (molecules) are treated on
the Born-Oppenheimer level using a binding potential calculated by Kolos and
Wolniewicz. The remaining interaction is then reduced to the scattering between
neutral particles which is reliably treated classically applying effective
potentials. The resulting Hugoniot is located between the experimental values
of Knudson {\textit{et al.}} \cite{1} and Collins {\textit{et al.}} \cite{2}.


title: Polarization tomography of metallic nanohole arrays

abstract:
  We report polarization tomography experiments on metallic nanohole arrays
with square and hexagonal symmetry. As a main result, we find that a fully
polarized input beam is partly depolarized after transmission through a
nanohole array. This loss of polarization coherence is found to be anisotropic,
i.e. it depends on the polarization state of the input beam. The depolarization
is ascribed to a combination of two factors: i) the nonlocal response of the
array due to surface plasmon propagation, ii) the non-plane wave nature of a
practical input beam.


title:
Field equations in teleparallel spacetime: Einstein's Fernparallelismus
  approach towards unified field theory

abstract:
  A historical account of Einstein's 'Fernparallelismus' approach towards a
unified field theory of gravitation and electromagnetism is given. In this
theory, a space-time characterized by a curvature-free connection in
conjunction with a metric tensor field, both defined in terms of a dynamical
tetrad field, is investigated. The approach was pursued by Einstein in a number
of publications that appeared in the period from summer 1928 until spring 1931.
In the historical analysis special attention is given to the question of how
Einstein tried to find field equations for the tetrads. We claim that it was
the failure to find and justify a uniquely determined set of acceptable field
equations which eventually led to Einstein's abandoning of this approach. We
comment on some historical and systematic similarities between the
'Fernparallelismus' episode and the 'Entwurf' theory, i.e. the precursor theory
of general relativity pursued by Einstein in the years 1912-1915.


title: Energy conservation laws in classical electrodynamics

abstract:
  There are three electromagnetic integrals of motion that can be interpreted
as the energy. These are the background energy, the elastic energy and the
integral in the torsion field commonly referred to as the energy of the
electromagnetic field. The integral in the torsion field gains the meaning of
the energy insomuch as it is concerned with the mechanical energy of a charged
particle.


title: Postulated Mesoscale Quantum of Internal Friction Hysteresis

abstract:
  Evidence is provided, from yet another experiment, for the existence of a
mesoscale quantum of internal friction hysteresis, having the value of the
electron rest energy divided by the fine structure constant.


title:
Seismic Activity in Tucunduba Reservoir, Senador Sa-CE, Brazil,
  1997-1998

abstract:
  The Tucunduba Dam is about 290 km West of Fortaleza, Cear\'a state. The
seismic monitoring of the area, with a local network, has began on June 11,
1997, soon after the occurrence of the event with magnitude 3.2 $m_b$ on June
09, 1997. The monitoring was done with one the analogical station (used for
magnitude duration measurement and statistical control activity) and seven
digital stations. The digital stations, with three components each, were
operated from June to November 1997. In this work, the data collected during
digital monitoring was analyzed to determine hypocenters and focal mechanism.
To determine hypocenters, the HYPO71 program was used, with half-space model,
whose parameters were 5.95 km/s, for P-wave velocities, and 1.69 for the ratio
between P and S-wave velocity. The active zone was nearly 1 km length, with
depth between 4.5 and 5.2 km. With 16 events recorded in the same six stations,
we determined the direction of the fault plane (NE-SW). The fault mechanism is
strike-slip with a small normal component. The dip estimate was 65$^{\circ}$SE
with FPFIT and 80$^{\circ}$SE with FOCMEC. Preliminary estimates of maximum
horizontal compressive stress, using P-axis direction, were in accordance with
Ferreira {\it et al.}(1998). The small difference is probably due to influence
of the sedimentary basin in the regional stress. The active area is in
accordance with seismicity described by Assump\c{c}\~ao (1998), i. e., the
combination regional stress, local flexural effect from thick sedimentary
loads, and a presumably weaker crust from Mesozoic thinning.


title: Induction and Mutually Obstructing Equilibria

abstract:
  A unified, consistent and simple view of the Faraday law of induction is
presented, which consists of two points: discriminating the lab- from the
rest-frame electric field and understanding it is the impossibility for both
fields to vanish simultaneously, which generates and maintains the circular
current. A number of illustrative examples are considered, including a
mechano-electric pendulum to exhibit periodic and reversible conversion between
electrical and mechanical energy.


title: 'Dark Matter' as a Quantum Foam In-Flow Effect

abstract:
  The galactic `dark matter' effect is regarded as one of the major problems in
fundamental physics. Here it is explained as a self-interaction dynamical
effect of space itself, and so is not caused by an unknown form of matter.
Because it was based on Kepler's Laws for the motion of the planets in the
solar system the Newtonian theory of gravity was too restricted. A
reformulation and generalisation of the Newtonian theory of gravity in terms of
a velocity in-flow field, representing at a classical level the relative motion
of a quantum-foam substructure to space, reveals a key dynamical feature of the
phenomenon of gravity, namely the so called `dark matter' effect, which
manifests not only in spiral galaxy rotation curves, but also in the borehole g
anomaly, globular and galactic black holes, and in ongoing problems in
improving the accuracy with which Newton's gravitational constant G is
measured. The new theory of gravity involves an additional new dimensionless
gravitational constant, and experimental data reveals this to be the fine
structure constant. The new theory correctly predicts the globular cluster
black hole masses, and that the `frame-dragging' effect is caused by vorticity
in the in-flow. The relationship of the new theory of gravity to General
Relativity which, like Newtonian gravity, does not have the `dark matter'
dynamics, is explained.


title: Experimental test of magnetic photons

abstract:
  A "magnetic" photon hypothesis associated with magnetic monopoles is tested
experimentally. These photons are predicted to easily penetrate metal.
Experimentally the optical transmittance T of a metal foil was less than 2 x
10^-17. The hypothesis is not supported since it predicts T = 2 x 10^-12.


title: Table-top synchrotron

abstract:
  Using three-dimensional particle-in-cell simulations we show that a strongly
nonlinear plasma wave excited by an ultrahigh intensity laser pulse works as a
compact high-brightness source of X-ray radiation. It has been recently
suggested by A. Pukhov and J. Meyer-ter-Vehn, Appl. Phys. B \textbf{74}, 355
(2002), that in a strongly nonlinear regime the plasma wave transforms to a
``bubble'', which is almost free from background electrons. Inside the bubble,
a dense bunch of relativistic electrons is produced. These accelerated
electrons make betatron oscillations in the transverse fields of the bubble and
emit a bright broadband X-ray radiation with a maximum about 50 keV. The
emission is confined to a small angle of about 0.1 rad. In addition, we make
simulations of X-ray generation by an external 28.5-GeV electron bunch injected
into the bubble. $\gamma$-quanta with up to GeV energies are observed in the
simulation in a good agreement with analytical results. The energy conversion
is efficient, leading to a significant stopping of the electron bunch over 5 mm
interaction distance.


title:
Second virial coefficient in one dimension, as a function of asymptotic
  quantities

abstract:
  A result from Dodd and Gibbs[1] for the second virial coefficient of
particles in 1 dimension, subject to delta-function interactions, has been
obtained by direct integration of the wave functions. It is shown that this
result can be obtained from a phase shift formalism, if one includes the
contribution of oscillating terms. The result is important in work to follow,
for the third virial coefficient, for which a similar formalism is being
developed. We examine a number of fine points in the quantum mechanical
formalisms.


title: The Causal Event Set

abstract:
  To clarify some aspects of the application of Special Relativity, spacetime
is sliced into null geodesic hypersurfaces as an alternative to the
hypersurfaces of simultaneity normally adopted. Events at particle locations on
the hypersurface are identified as the causal event set. It is demonstrated
that a Lorentz boost applied to the causal event set maintains the property of
connectedness and with this formalism it is simple to derive the redshift
equation. The twin paradox is naturally explained as an instantaneous
reconfiguration of particle position 4-vectors in the frame of the accelerated
object. The metaphysical implications are examined with the tentative
conclusion that a relationist view of spacetime is more consistent with this
treatment than the substantivalist viewpoint.


title:
Mechanisms of DNA separation in entropic trap arrays: A Brownian
  dynamics simulation

abstract:
  Using Brownian dynamics simulations, we study the migration of long charged
chains in an electrophoretic microchannel device consisting of an array of
microscopic entropic traps with alternating deep regions and narrow
constrictions. Such a device has been designed and fabricated recently by Han
et al. for the separation of DNA molecules (Science, 2000). Our simulation
reproduces the experimental observation that the mobility increases with the
length of the DNA. A detailed data analysis allows to identify the reasons for
this behavior. Two distinct mechanisms contribute to slowing down shorter
chains. One has been described earlier by Han et al.: the chains are delayed at
the entrance of the constriction and escape with a rate that increases with
chain length. The other, actually dominating mechanism is here reported for the
first time: Some chains diffuse out of their main path into the corners of the
box, where they remain trapped for a long time. The probability that this
happens increases with the diffusion constant, i.e., the inverse chain length.


title: Confined three-dimensional stability analysis of the cylinder wake

abstract:
  A spatially confined stability analysis is reported for the cylinder wake at
Reynolds numbers 190 and 260. The two three-dimensional instabilities at these
Reynolds numbers are shown to be driven by the flow just behind the cylinder.


title: The ATLAS Tile Calorimeter Test Beam Monitoring Program

abstract:
  During 2003 test beam session for ATLAS Tile Calorimeter a monitoring program
has been developed to ease the setup of correct running condition and the
assessment of data quality. The program has been built using the Online
Software services provided by the ATLAS Online Software group. The first part
of this note contains a brief overview of these services followed by the full
description of Tile Calorimeter monitoring program architecture and features.
Performances and future upgrades are discussed in the final part of this note.


title:
Different Particle Sizes Obtained from Static and Dynamic Laser Light
  Scattering

abstract:
  Detailed investigation of static and dynamic laser light scattering has been
attempted in this work both theoretically and experimentally based on dilute
water dispersions of two different homogenous spherical particles, polystyrene
latexes and poly($N$-isopropylacrylamide) microgels. When Rayleigh-Gans-Debye
approximation is valid, a new radius $R_{s}$, referred to as a static radius,
can be obtained from the static light scattering $(SLS) $. If the absolute
magnitude of the scattered intensity and some constants that are related to the
instrument and samples are known, the average molar mass for large particles
can be measured. The size information obtained from SLS is purely related to
the optical properties of particles, i.e., to $R_{s}$ and its distribution
$G(R_{s}) $. The size information obtained from dynamic light scattering $(DLS)
$ is more complicated, the size distribution of which is a composite
distribution that is not only related to the optical properties of particles,
but also related to the hydrodynamic properties and the scattering vector.
Strictly speaking, an apparent hydrodynamic radius $R_{h,app}$ is a composite
size obtained from averaging the term $\exp (-q^{2}D\tau) $ in the static size
distribution $G(R_{s}) $, with the weight $R_{s}^{6}P(q,R_{s}) $ that is also a
function of both $R_{s}$ and the scattering vector $q$.


title:
Maple procedures for the coupling of angular momenta. VI. LS-jj
  transformations

abstract:
  Transformation matrices between different coupling schemes are required, if a
reliable classification of the level structure is to be obtained for open-shell
atoms and ions. While, for instance, relativistic computations are
traditionally carried out in jj-coupling, a LSJ coupling notation often occurs
much more appropriate for classifying the valence-shell structure of atoms.
Apart from the (known) transformation of single open shells, however, further
demand on proper transformation coefficients has recently arose from the study
of open d- and f-shell elements, the analysis of multiple--excited levels, or
the investigation on inner-shell phenomena. Therefore, in order to facilitate a
simple access to LS <-> jj transformation matrices, here we present an
extension to the Racah program for the set-up and the transformation of
symmetry-adapted functions. A flexible notation is introduced for defining and
for manipulating open-shell configurations at different level of complexity
which can be extended also to other coupling schemes and, hence, may help
determine an optimum classification of atomic levels and processes in the
future.


title: Some Consequences of Fuzzy Spacetime

abstract:
  In this paper we analyse the reasons which lead to a fuzzy spacetime
approach. We then consider an experimental consequence, viz., a modified
dispersion relation, which could be detected in ultra high energy cosmic rays,
by for example NASA's GLAST Satellite scheduled to be launched in 2006. We also
study the implications for the theory of non-Abelian Gauge Fields.


title: Development of Novel Density Functionals for Thermochemical Kinetics

abstract:
  A new density functional theory (DFT) exchange-correlation functional for the
exploration of reaction mechanisms is proposed. This new functional, denoted
BMK (Boese-Martin for Kinetics), has an accuracy in the 2 kcal/mol range for
transition state barriers but, unlike previous attempts at such a functional,
this improved accuracy does not come at the expense of equilibrium properties.
This makes it a general-purpose functional whose domain of applicability has
been extended to transition states, rather than a specialized functional for
kinetics. The improvement in BMK rests on the inclusion of the kinetic energy
density together with a large value of the exact exchange mixing coefficient.
For this functional, the kinetic energy density appears to correct `back' the
excess exact exchange mixing for ground-state properties, possibly simulating
variable exchange.


title: Ultra Low-Power All-Optical Switching

abstract:
  Using analytical modeling and detailed numerical simulations, we investigate
properties of hybrid systems of Photonic Crystal micro-cavities which
incorporate a highly non-linear Ultra Slow Light medium. We demonstrate that
such systems, while being miniature in size (order wavelength), and integrable,
could enable ultra-fast non-linear all-optical switching at single photon
energy levels.


title: Extension of the HF program to partially filled f-subshells

abstract:
  A new version of a Hartree-Fock program is presented that includes extensions
for partially filled f-subshells. The program allows the calculation of term
dependent Hartree-Fock orbitals and energies in LS coupling for configurations
with no more than two open subshells, including f-subshells.


title:
Pattern Recognition and Data Compression for the ALICE High Level
  Trigger

abstract:
  The central detectors of the ALICE experiment at LHC will produce a data size
of up to 75 MByte/event at an event rate <200 Hz resulting in a data rate of
\~15 GByte/sec. This exceeds the foreseen mass storage bandwidth of 1.25
GByte/sec by one order of magnitude. Online processing of the data is necessary
in order to select interesting (sub)events ("High Level Trigger"), or to
compress data efficiently by modeling techniques.
  The largest computing challenge is imposed by the TPC, requiring realtime
pattern recognition. The work carried out investigates the performance of
various pattern recognition schemes applicable for online track reconstruction
within the ALICE HLT system. Furthermore, as an application for reducing the
data rate, very efficient TPC data compression algorithms based on track and
cluster modeling have been evaluated.


title: Thermodynamic derivation of reciprocal relations

abstract:
  Reciprocal relations correlate fairly accurately a great variety of
experimental results. Nevertheless, the concepts of statistical fluctuations,
and microscopic reversibility - the bases of the accepted proof of the
relations by Onsager - are illusory and faulty, and contradict the foundations
of the science of thermodynamics. The definitions, postulates, and main
theorems of thermodynamics are briefly presented. It is shown beyond a shadow
of a doubt that thermodynamics is a nonstatistical science that applies to all
systems (both macroscopic, and microscopic, including systems that consist
either of only one structureless particle, or only one spin), to all states
(both thermodynamic or stable equilibrium, and not stable equilibrium), and
that includes entropy as a well defined, intrinsic, nonstatistical property of
any system in any state, at any instant in time. In the light of this novel
conception of thermodynamics, we find that reciprocal relations result from a
well known mathematical theorem, to wit, given a well behaved analytic function
of many variables then the second derivative of the function with respect to
any two variables is independent of the order of differentiation, namely,
whether the first derivative is taken with respect to the one or the other of
the two variables.


title: Ultraviolet photonic crystal laser

abstract:
  We fabricated two dimensional photonic crystal structures in zinc oxide films
with focused ion beam etching. Lasing is realized in the near ultraviolet
frequency at room temperature under optical pumping. From the measurement of
lasing frequency and spatial profile of the lasing modes, as well as the
photonic band structure calculation, we conclude that lasing occurs in the
strongly localized defect modes near the edges of photonic band gap. These
defect modes originate from the structure disorder unintentionally introduced
during the fabrication process.


title:
Spectroscopic LSJ notation for atomic levels obtained from relativistic
  calculations

abstract:
  Today, relativistic calculations are known to provide a very successful means
in the study of open-shell atoms and ions. But although accurate atomic data
are obtained from these computations, they are traditionally carried out in
jj-coupling and, hence, do often not allow for a simple LSJ classification of
the atomic levels as needed by experiment. In fact, this lack of providing a
proper spectroscopic notation from relativistic structure calculations has
recently hampered not only the spectroscopy of medium and heavy elements, but
also the interpretation and analysis of inner-shell processes, for which the
occurrence of additional vacancies usually leads to a very detailed fine
structure.
  Therefore, in order to facilitate the classification of atomic levels from
such computations, here we present a program (within the Ratip environment)
which help transform the atomic wave functions from jj-coupled
multiconfiguration Dirac-Fock computations into a LS-coupled representation.
Beside of a proper LSJ assignment to the atomic levels, the program also
supports the full transformation of the wave functions if required for
(nonrelativistic) computations.


title:
Design of laser-electron storage ring lattice dedicated to generation of
  intense X-rays under Compton scattering

abstract:
  The lattice of laser-electron storage ring with controlled momentum
compaction factor dedicated to generation of intense X-rays under Compton
scattering is described. In such storage ring one can achieve the large energy
acceptance and keep the long-term stable motion of electron beam with large
energy spread. The intensity of X-rays may be very stable due to using of
electron beam with steady-state parameters for Compton scattering. Parameters
of the storage ring, electron beam and X-rays obtained by electron beam
dynamics simulation involving Compton scattering are presented.


title: Two-State Migration of DNA in a structured Microchannel

abstract:
  DNA migration in topologically structured microchannels with periodic
cavities is investigated experimentally and with Brownian dynamics simulations
of a simple bead-spring model. The results are in very good agreement with one
another. In particular, the experimentally observed migration order of Lambda-
and T2-DNA molecules is reproduced by the simulations. The simulation data
indicate that the mobility may depend on the chain length in a nonmonotonic way
at high electric fields. This is found to be the signature of a nonequilibrium
phase transition between two different migration states, a slow one and a fast
one, which can also be observed experimentally under appropriate conditions.


title: On the Origin of Kaluza's Idea of Unification

abstract:
  We argue that the starting point of Kaluza's idea of unifying electrodynamics
and gravity was the analogy between gravitation and electromagnetism which was
pointed out by Einstein and Thirring. It seems that Kaluza's attention was
turned to this point by the three papers on the Lense-Thirring effect and the
analogy between gravitation and electromagnetism which were published a short
time before Kaluza's paper was submitted. We provide here an English
translation of the third of these papers.


title: On the Electrodynamics with Faster-Than-Light Motion

abstract:
  The version of electrodynamics is constructed in which faster-than-light
motions of fields and particles with real masses are possible. Transformational
properties of 3-velocity, momentum, energy and electromagnetic field are
presented in addition to the paper physics/0405085.


title:
Stochastic and Discrete Time Models of Long-Range Turbulent Transport in
  the Scrape-Off Layer

abstract:
  Two dimensional stochastic time model of scrape-off layer (SOL) turbulent
transport is studied. Instability arisen in the system with respect to the
stochastic perturbations of both either density or vorticity reveals itself in
the strong outward bursts of particle density propagating ballistically across
the SOL. The stability and possible stabilization of the cross- field turbulent
system depend very much upon the reciprocal correlation time between density
and vorticity fluctuations. Pdf of the particle flux for the large magnitudes
of flux events can be modelled with a simple discrete time toy model of random
walks concluding at a boundary. The spectra of wandering times feature the pdf
of particle flux in the model and qualitatively reproduce the experimental
statistics of transport events.


title: Quantum Entanglement, Cognition & The Processes of Inference

abstract:
  Church's hypothesis and Godel's theorem may provide constraints on mental
processes.As a relief quantum entanglement may lead to a definite proposal as
regards the nature of reality and how much of it we are able to know and how do
we know it.We deal with these questions and have devised a Gedanken Experiment
showing the redundancy of principle of reality. We thereby propose a model
describing the processes of making conclusions from a given set of premises
though without the reference of neurobiological processes at present. We argue
thereafter that the physical laws of nature may not be universal as it seems,
being dependent on some physical processes namely computation and the states of
neural cognitive states which may be governed yet by some other rule.


title: Longitudinal Momentum Mining of Beam Particles in a Storage Ring

abstract:
  I describe a new scheme for selectively isolating high density low
longitudinal emittance beam particles in a storage ring from the rest of the
beam without emittance dilution. I discuss the general principle of the method,
called longitudinal momentum mining, beam dynamics simulations and results of
beam experiments. Multi-particle beam dynamics simulations applied to the
Fermilab 8 GeV Recycler (a storage ring) convincingly validate the concepts and
feasibility of the method, which I have demonstrated with beam experiments in
the Recycler. The method presented here is the first of its kind.


title: Quantum nRules

abstract:
  Quantum mechanics traditionally places the observer outside of the system
being studied and employs the Born interpretation. In this and related papers
the observer is placed inside the system. To accomplish this, special rules are
required to engage and interpret the Schrodinger solutions in individual
measurements. The rules in this paper (called the nRules) do not include the
Born rule that connects probability with square modulus. It is required that
the rules allow all conscious observers to exist inside the system without
empirical ambiguity, reflecting our own unambiguous experience in the universe.
This requirement is satisfied by the nRules. They allow both objective and
observer measurements, so state reduction can occur with or without an observer
being present. Keywords: brain states, consciousness, decoherence,
epistemology, measurement, ontology, stochastic, state reduction, wave
collapse.


title: Relativistic and Radiative Energy Shifts for Rydberg States

abstract:
  We investigate relativistic and quantum electrodynamic effects for
highly-excited bound states in hydrogenlike systems (Rydberg states). In
particular, hydrogenic one-loop Bethe logarithms are calculated for all
circular states (l = n-1) in the range 20 <= n <= 60 and successfully compared
to an existing asymptotic expansion for large principal quantum number n. We
provide accurate expansions of the Bethe logarithm for large values of n, for
S, P and circular Rydberg states. These three expansions are expected to give
any Bethe logarithms for principal quantum number n > 20 to an accuracy of five
to seven decimal digits, within the specified manifolds of atomic states.
Within the numerical accuracy, the results constitute unified, general formulas
for quantum electrodynamic corrections whose validity is not restricted to a
single atomic state. The results are relevant for accurate predictions of
radiative shifts of Rydberg states and for the description of the recently
investigated laser-dressed Lamb shift, which is observable in a strong
coherent-wave light field.


title: Quantum Brain oRules

abstract:
  Quantum mechanics traditionally places the observer outside of the system
being studied and employs the Born interpretation. In this and related papers
the observer is placed inside the system. To accomplish this, special rules are
required to engage and interpret the Schrodinger solutions in individual
measurements. The rules in this paper (called the oRules) do not include the
Born rule that connects probability with square modulus. It is required that
the rules allow conscious observers to exist inside the system without
empirical ambiguity, reflecting our own unambiguous experience in the universe.
This requirement is satisfied by the oRules. These rules are restricted to
observer measurements, so state reduction can only occur when an observer is
present. Keywords: brain states, decoherence, epistemological model,
ontological model, stochastic choice, state reduction, von Neumann, wave
collapse.


title: Open-source software for generating electrocardiogram signals

abstract:
  ECGSYN, a dynamical model that faithfully reproduces the main features of the
human electrocardiogram (ECG), including heart rate variability, RR intervals
and QT intervals is presented. Details of the underlying algorithm and an
open-source software implementation in Matlab, C and Java are described. An
example of how this model will facilitate comparisons of signal processing
techniques is provided.


title:
Wavelength dependent ac-Stark shift of the 1S0 - 3P1 transition at 657
  nm in Ca

abstract:
  We have measured the ac-Stark shift of the 4s2 1S0 - 4s4p 3P1 line in 40Ca
for perturbing laser wavelengths between 780 nm and 1064 nm with a time domain
Ramsey-Borde atom interferometer. We found a zero crossing of the shift for the
mS = 0 - mP = 0 transition and \sigma polarized perturbation at 800.8(22) nm.
The data was analyzed by a model deriving the energy shift from known
transition wavelengths and strengths. To fit our data, we adjusted the Einstein
A coefficients of the 4s3d 3D - 4s4p 3P and 4s5s 3S - 4s4p 3P fine structure
multiplets. With these we can predict vanishing ac-Stark shifts for the 1S0 m =
0 - 3P1 m = 1 transition and \sigma- light at 983(12) nm and at 735.5(20) nm
for the transition to the 3P0 level.


title: Coherent Harmonic Focusing and the Light Extreme

abstract:
  We demonstrate analytically and numerically that focusing of high harmonics
produced by the reflection of a few femtosecond laser pulse from a concave
plasma surface opens a new way towards unprecedentally high intensities. The
key features allowing for boosting of the focal intensity is the harmonic
coherency and the small exponent of the power-law decay of the harmonic
spectrum. Using the similarity theory and direct particle-in-cell simulations
we find that the intensity at the Coherent Harmonic Focus (CHF) scales as
$I_{\tiny CHF} \propto a_0^3 I_0$, where $a_0$ and $I_0\propto a_0^2$ are the
dimensionless relativistic amplitude and the intensity of the incident laser
pulse. The scaling suggests that due to the CHF, the Schwinger intensity limit
can be achieved using lasers with $I_0 \approx 10^{22}$ W/cm$^2$. The pulse
duration at the focus scales as $\tau_{\tiny CHF} \propto 1/a_0^2$ and reaches
the subattosecond range.


title:
Formalism for obtaining nuclear momentum distributions by the Deep
  Inelastic Neutron Scattering technique

abstract:
  We present a new formalism to obtain momentum distributions in condensed
matter from Neutron Compton Profiles measured by the Deep Inelastic Neutron
Scattering technique. The formalism describes exactly the Neutron Compton
Profiles as an integral in the momentum variable $y$. As a result we obtain a
Volterra equation of the first kind that relates the experimentally measured
magnitude with the momentum distributions of the nuclei in the sample. The
integration kernel is related with the incident neutron spectrum, the total
cross section of the filter analyzer and the detectors efficiency function. A
comparison of the present formalism with the customarily employed approximation
based on a convolution of the momentum distribution with a resolution function
is presented. We describe the inaccuracies that the use of this approximation
produces, and propose a new data treatment procedure based on the present
formalism.


title: On the Persistence of Homogeneous Matter

abstract:
  Some recent philosophical debate about persistence has focussed on an
argument against perdurantism that discusses rotating perfectly homogeneous
discs (the `rotating discs argument'; RDA). The argument has been mostly
discussed by metaphysicians, though it appeals to ideas from classical
mechanics, especially about rotation. In contrast, I assess the RDA from the
perspective of the philosophy of physics.
  After introducing the argument and emphasizing the relevance of physics
(Sections 1 to 3), I review some metaphysicians' replies to the argument
(Section 4). Thereafter, I argue for three main conclusions. They all arise
from the fact, emphasized in Section 2, that classical mechanics
(non-relativistic as well as relativistic) is both more subtle, and more
problematic, than philosophers generally realize.
  The main conclusion is that the RDA can be defeated (Section 6 onwards).
Namely, by the perdurantist taking objects in classical mechanics (whether
point-particles or continuous bodies) to have only temporally extended, i.e.
non-instantaneous, temporal parts: which immediately blocks the RDA.
Admittedly, this version of perdurantism defines persistence in a weaker sense
of `definition' than {\em pointilliste} versions that aim to define persistence
assuming only instantaneous temporal parts. But I argue that temporally
extended temporal parts are supported by both classical and quantum mechanics.


title:
Non-divergent pseudo-potential treatment of spin-polarized fermions
  under 1D and 3D harmonic confinement

abstract:
  Atom-atom scattering of bosonic one-dimensional (1D) atoms has been modeled
successfully using a zero-range delta-function potential, while that of bosonic
3D atoms has been modeled successfully using Fermi-Huang's regularized s-wave
pseudo-potential. Here, we derive the eigenenergies of two spin-polarized 1D
fermions under external harmonic confinement interacting through a zero-range
potential, which only acts on odd-parity wave functions, analytically. We also
present a divergent-free zero-range potential treatment of two spin-polarized
3D fermions under harmonic confinement. Our pseudo-potential treatments are
verified through numerical calculations for short-range model potentials.


title:
Maximum Entropy Multivariate Density Estimation: An exact
  goodness-of-fit approach

abstract:
  We consider the problem of estimating the population probability distribution
given a finite set of multivariate samples, using the maximum entropy approach.
In strict keeping with Jaynes' original definition, our precise formulation of
the problem considers contributions only from the smoothness of the estimated
distribution (as measured by its entropy) and the loss functional associated
with its goodness-of-fit to the sample data, and in particular does not make
use of any additional constraints that cannot be justified from the sample data
alone. By mapping the general multivariate problem to a tractable univariate
one, we are able to write down exact expressions for the goodness-of-fit of an
arbitrary multivariate distribution to any given set of samples using both the
traditional likelihood-based approach and a rigorous information-theoretic
approach, thus solving a long-standing problem. As a corollary we also give an
exact solution to the `forward problem' of determining the expected
distributions of samples taken from a population with known probability
distribution.

categories: physics.data-an cs.IT math.IT math.ST stat.TH


title: Constancy of any signal velocity in all inertial frames

abstract:
  If isotropy of space and homogeneity of space and time are the valid laws of
nature then one can show that velocity of any signal (whether it is light in a
vacuum or in a medium or something having constant velocity in the rest frame
of the observer and by using which we can perform all (but not partial)
measurements of all physical quantities related with the particular experiment)
is constant in all inertial frames. To verify this constancy for other signals
apart from light in vacuum (which is well-known) we have proposed particularly
one experiment in which all measurements can be done using light in water as
signal. If we perform experiment in a medium then the signal connecting the
measurements of an event in two inertial frames can not be light in vacuum
rather it is light in the medium. In such cases where signal used for
measurement is not light in vacuum, relativistic relationships of various
physical quantities in Special Theory of Relativity (in which light in vacuum
has been used as signal) require modifications. This work might be verified
from the analysis related with the number of cosmic muons reaching earth
through atmosphere or that related with the amount of oscillation of
atmospheric neutrinos as in both these cases signal for our measurement can not
be light in vacuum but it is light in air.


title:
The Eddy Experiment: accurate GNSS-R ocean altimetry from low altitude
  aircraft

abstract:
  During the Eddy Experiment, two synchronous GPS receivers were flown at 1 km
altitude to collect L1 signals and their reflections from the sea surface for
assessment of altimetric precision and accuracy. Wind speed (U10) was around 10
m/s, and SWH up to 2 m. A geophysical parametric waveform model was used for
retracking and estimation of the lapse between the direct and reflected signals
with a 1-second precision of 3 m. The lapse was used to estimate the SSH along
the track using a differential model. The RMS error of the 20 km averaged
GNSS-R absolute altimetric solution with respect to Jason-1 SSH and a GPS buoy
measurement was of 10 cm, with a 2 cm mean difference. Multipath and retracking
parameter sensitivity due to the low altitude are suspected to have degraded
accuracy. This result provides an important milestone on the road to a GNSS-R
mesoscale altimetry space mission.


title: Euclidean formulation of general relativity

abstract:
  A variational principle is applied to 4D Euclidean space provided with a
tensor refractive index, defining what can be seen as 4-dimensional optics
(4DO). The geometry of such space is analysed, making no physical assumptions
of any kind. However, by assigning geometric entities to physical quantities
the paper allows physical predictions to be made. A mechanism is proposed for
translation between 4DO and GR, which involves the null subspace of 5D space
with signature $(-++++)$. A tensor equation relating the refractive index to
sources is established geometrically and the sources tensor is shown to have
close relationship to the stress tensor of GR. This equation is solved for the
special case of zero sources but the solution that is found is only applicable
to Newton mechanics and is inadequate for such predictions as light bending and
perihelium advance. It is then argued that testing gravity in the physical
world involves the use of a test charge which is itself a source. Solving the
new equation, with consideration of the test particle's inertial mass, produces
an exponential refractive index where the Newtonian potential appears in
exponent and provides accurate predictions. Resorting to hyperspherical
coordinates it becomes possible to show that the Universe's expansion has a
purely geometric explanation without appeal to dark matter.


title:
Calculation of the elastic scattering parameters in an ultra-cold
  Fermi-Bose and Bose-Bose Fr vapor

abstract:
  The calculations of the elastic scattering properties of ultracold-francium
isotopes are reported in the detail. A parametric model potential for the
triplet molecular states of the Fr$_{2}$ is represented, and the scattering
lengths at and the effective range $r_{e}$ are calculated using WKB and Numerov
methods for Fr-Fr in the triplet state. The convergence of these scattering
properties as the depending on a $K_{0}$ parameter and core radius is also
investigated using two method as Quantum Defect Theory and analytical formula
of symskovisky.


title:
Efficient excitation of cavity resonances of subwavelength metallic
  gratings

abstract:
  One dimensional rectangular metallic gratings enable enhanced transmission of
light for specific resonance frequencies. Two kinds of modes participating to
enhanced transmission have already been demonstrated : (i) waveguide modes and
(ii) surface plasmon polaritons (SPP). Since the original paper of Hessel and
Oliner \cite{hessel} pointing out the existence of (i), no progress was made in
their understanding. We present here a carefull analysis, and show that the
coupling between the light and such resonances can be tremendously improved
using an {\it evanescent} wave. This leads to enhanced localisation of light in
cavities, yielding, in particular, to a very selective light transmission
through these gratings.


title: Sea state monitoring using coastal GNSS-R

abstract:
  We report on a coastal experiment to study GPS L1 reflections. The campaign
was carried out at the Barcelona Port breaker and dedicated to the development
of sea-state retrieval algorithms. An experimental system built for this
purpose collected and processed GPS data to automatically generate a times
series of the interferometric complex field (ICF). The ICF was analyzed off
line and compared to a simple developed model that relates ICF coherence time
to the ratio of significant wave height (SWH) and mean wave period (MWP). The
analysis using this model showed good consistency between the ICF coherence
time and nearby oceanographic buoy data. Based on this result, preliminary
conclusions are drawn on the potential of coastal GNSS-R for sea state
monitoring using semi-empirical modeling to relate GNSS-R ICF coherence time to
SWH.


title: Fermi, Majorana and the statistical model of atoms

abstract:
  We give an account of the appearance and first developments of the
statistical model of atoms proposed by Thomas and Fermi, focusing on the main
results achieved by Fermi and his group in Rome. Particular attention is
addressed to the unknown contribution to this subject by Majorana, anticipating
some important results reached later by leading physicists.

categories: physics.hist-ph hep-ph hep-th physics.atom-ph


title: Focusing limits of channeled high energy particles in bent crystals

abstract:
  The focusing of high energy charged particles by a bent crystal is
considered. The limits and constraints of focusing imposed by dynamics of
particles are pointed out. The crystalline geometry provided the maximum
magnification and minimum focusing size is proposed. The focusing parameters
are compared with current experimental results.


title: Dynamics of the tuning process between singers

abstract:
  We present a dynamical model describing a predictable human behavior like the
tuning process between singers. The purpose, inspired in physiological and
behavioral grounds of human beings, is sensitive to all Fourier spectrum of
each sound emitted and it contemplates an asymmetric coupling between
individuals. We have recorded several tuning exercises and we have confronted
the experimental evidence with the results of the model finding a very well
agreement between calculated and experimental sonograms.


title: Helicity Basis for Spin 1/2 and 1

abstract:
  We study the theory of the (1/2,0)+(0,1/2) and (1,0)+(0,1) representations in
the helicity basis. The helicity eigenstates are not the parity eigenstates.
This is in accordance with the idea of Berestetskii, Lifshitz and Pitaevskii.
The behaviour of the helicity eigenstates with respect to the charge
conjugation, CP- conjugation is also different comparing with the parity
eigenstates.


title: Water waves over a strongly undulating bottom

abstract:
  Two-dimensional free-surface potential flows of an ideal fluid over a
strongly inhomogeneous bottom are investigated with the help of conformal
mappings. Weakly-nonlinear and exact nonlinear equations of motion are derived
by the variational method for arbitrary seabed shape parameterized by an
analytical function. As applications of this theory, band structure of linear
waves over periodic bottoms is calculated and evolution of a strong solitary
wave running from a deep region to a shallow region is numerically simulated.


title:
The effect of the incident relative phase on the four-wave mixing field
  and the electromagnetically induced transparency

abstract:
  In a Lambda-type system employing a two-photon pump field, a four-wave mixing
field can be generated simultaneously and hence a closed-loop system forms. We
study theoretically on the effect of the relative phase between the two
incident fields on the generated four-wave mixing field and the
electromagnetically induced transparency. It is found that the phase of the
generated four-wave mixing field is a sum of the incident relative phase and a
fixed phase which is irrelative to the incident relative phase. Hence the total
phase of the closed-loop system is independent of the incident relative phase.
As a result, the incident relative phase has no effect on electromagnetically
induced transparency, which is different from the case of a Lambda-type loop
system closed by a third incident field.


title:
An Exact Formula to Describe the Amplification Process in a
  Photomultiplier Tube

abstract:
  An analytical function is derived that exactly describes the amplification
process due to a series of discrete, Poisson-like amplifications like those in
a photo multiplier tube (PMT). A numerical recipe is provided that implements
this function as a computer program. It is shown how the program can be used as
the core-element of a faster, simplified routine to fit PMT spectra with high
efficiency. The functionality of the method is demonstrated by fitting both,
Monte Carlo generated and measured PMT spectra.


title: Linking Maxwell, Helmholtz and Gauss through the Linking Integral

abstract:
  We take the Gauss' linking integral of two curves as a starting point to
discuss the connection between the equation of continuity and the inhomogeneous
Maxwell equations. Gauss' formula has been discussed before, as being derivable
from the line integral of a magnetic field generated by a steady current
flowing through a loop. We argue that a purely geometrical result - such as
Gauss' formula - cannot be claimed to be derivable from a law of Nature, i.e.,
from one of Maxwell's equations, which is the departing point for the
calculation of the magnetic field. We thus discuss anew the derivation of
Gauss' formula, this time resting on Helmholtz's theorem for vector fields.
Such a derivation, in turn, serves to shed light into the connection existing
between a conservation law like charge conservation and the Maxwell equations.
The key role played by the constitutive equations in the construction of
Maxwell's electromagnetism is briefly discussed, as well.


title:
Controlled spatiotemporal excitation of metal nanoparticles with
  femtosecond pulses

abstract:
  We discuss finite-difference time-domain simulations of femtosecond pulses
interacting with silver nanowires and nanoparticles. We show how localized hot
spots near the metal surfaces can be generated and controlled in a
spatiotemporal manner. The control is made possible by chirping the pulses such
that the effective frequency passes through surface plasmon resonances
associated with different spatial regions of the nanostructure over the course
of time. The response of such nanostructures to chirped pulses could provide a
novel means of encoding or decoding optical signals.


title:
Electromagnetically induced left-handedness in a dense gas of three
  level atoms

abstract:
  We discuss how a three level system can be used to change the frequency
dependent magnetic permeability of an atomic gas to be significantly different
from one. We derive the conditions for such a scheme to be successful and
briefly discuss the resulting macroscopic electrodynamics. We find that it may
be possible to obtain left handed electrodynamics for an atomic gas using three
atomic levels.

categories: physics.atom-ph cond-mat.other cond-mat.soft physics.optics


title: Solving the Mystery of the Missing Neutrinos

abstract:
  The three years 2001 to 2003 were the golden years of solar neutrino
research. In this period, scientists solved a mystery with which they had been
struggling for four decades. The solution turned out to be important for both
physics and for astronomy. In this article, I tell the story of those fabulous
three years.

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


title: Hadron thermodynamics, concavity and negative heat capacities

abstract:
  Problems associated with the nonextensivity of a hadron gas were discussed
some time ago. Recently the topic has come to light again and here earlier
results are re-examined in the light of new knowledge and attention is drawn to
problems with the more modern work.


title:
Chemical reactivity of ultracold polar molecules: investigation of H +
  HCl and H + DCl collisions

abstract:
  Quantum scattering calculations are reported for the H+HCl(v,j=0) and
H+DCl(v,j=0) collisions for vibrational levels v=0-2 of the diatoms.
Calculations were performed for incident kinetic energies in the range 10-7 to
10-1 eV, for total angular momentum J=0 and s-wave scattering in the entrance
channel of the collisions. Cross sections and rate coefficients are
characterized by resonance structures due to quasibound states associated with
the formation of the H...HCl and H...DCl van der Waals complexes in the
incident channel. For the H+HCl(v,j=0) collision for v=1,2, reactive scattering
leading to H_2 formation is found to dominate over non-reactive vibrational
quenching in the ultracold regime. Vibrational excitation of HCl from v=0 to
v=2 increases the zero-temperature limiting rate coefficient by about 8 orders
of magnitude.


title:
An Anderson Impurity Model for Efficient Sampling of Adiabatic Potential
  Energy Surfaces of Transition Metal Complexes

abstract:
  We present a model intended for rapid sampling of ground and excited state
potential energy surfaces for first-row transition metal active sites. The
method is computationally inexpensive and is suited for dynamics simulations
where (1) adiabatic states are required "on-the-fly" and (2) the primary source
of the electronic coupling between the diabatic states is the perturbative
spin-orbit interaction among the 3d electrons. The model Hamiltonian we develop
is a variant of the Anderson impurity model and achieves efficiency through a
physically motivated basis set reduction based on the large value of the d-d
Coulomb interaction U_{d} and a Lanczos matrix diagonalization routine to solve
for eigenvalues. The model parameters are constrained by fits to the partial
density of states (PDOS) obtained from ab initio density functional theory
calculations. For a particular application of our model we focus on
electron-transfer occuring between cobalt ions solvated by ammonium,
incorporating configuration interaction between multiplet states for both metal
ions. We demonstrate the capability of the method to efficiently calculate
adiabatic potential energy surfaces and the electronic coupling factor we have
calculated compares well to previous calculations and experiment.


title:
Conformational Dependence of a Protein Kinase Phosphate Transfer
  Reaction

abstract:
  Atomic motions and energetics for a phosphate transfer reaction catalyzed by
the cAMP-dependent protein kinase (PKA) are calculated by plane-wave density
functional theory, starting from structures of proteins crystallized in both
the reactant conformation (RC) and the transition-state conformation (TC). In
the TC, we calculate that the reactants and products are nearly isoenergetic
with a 0.2 eV barrier; while phosphate transfer is unfavorable by over 1.2 eV
in the RC, with an even higher barrier. With the protein in the TC, the motions
involved in reaction are small, with only P$_\gamma$ and the catalytic proton
moving more than 0.5 \AA. Examination of the structures reveals that in the RC
the active site cleft is not completely closed and there is insufficient space
for the phosphorylated serine residue in the product state. Together, these
observations imply that the phosphate transfer reaction occurs rapidly and
reversibly in a particular conformation of the protein, and that the reaction
can be gated by changes of a few tenths of an \AA in the catalytic site.


title:
Spatially Varying Steady State Longitudinal Magnetization in Distant
  Dipolar Field-based Sequences

abstract:
  Sequences based on the Distant Dipolar Field (DDF) have shown great promise
for novel spectroscopy and imaging. Unless spatial variation in the
longitudinal magnetization, M_{z}(s), is eliminated by relaxation, diffusion,
or spoiling techniques by the end of a single repetition, unexpected results
can be obtained due to spatial harmonics in the steady state M_{z}^{SS}(s)
profile. This is true even in a homogeneous single-component sample. We have
developed an analytical expression for the M_{z}^{SS}(s) profile that occurs in
DDF sequences when smearing by diffusion is negligible in the TR period. The
expression has been verified by directly imaging the M_{z}^{SS}(s) profile
after establishing the steady state. more keywords: magnetic resonance,
intermolecular multiple quantum coherence, mesoscale structure, iMQC, DDF


title: Nuclear Power and the World's Energy Requirements

abstract:
  The global requirements for energy are increasing rapidly as the global
population increases and the under-developed nations become more advanced. The
traditional fuels used in their traditional ways will become increasingly
unable to meet the demand. The need for a review of the energy sources
available is paramount, although the subsequent need to develop a realistic
strategy to deal with all local and global energy requirements is almost as
important. Here attention will be restricted to examining some of the claims
and problems of using nuclear power to attempt to solve this major question.


title:
Two-dimensional PIC-MCC simulations of capacitively coupled
  radio-frequency discharge in methane

abstract:
  Two-dimensional capacitively coupled radio frequency discharge in methane is
simulated by PIC-MCC method. The results were obtained in pressure range 50-300
mTorr and voltage range 40-180 V for discharge frequency 13.56 MHz. The
electron energy and electron--methane reaction rates spatial distributions show
existence of two regimes of discharge glow: a) with active sheaths, when
electrons are hot in electrode sheaths and cold in the middle of discharge so
the electron-neutral reactions strongly dominate in sheaths regions; b) with
volume domination, when the electron energy is more uniform and the reactions
take place in all discharge volume. The second regime is usually observed for
low discharge voltages, and turns to the first one with voltage increasing.
Besides, simulation of chemical reactions in methane plasma was also fulfilled
to find the gas mixture composition in discharge volume. The results are in
agreement with the known experimental data.


title: Atomic physics: computer calculations and theoretical analysis

abstract:
  It is demonstrated, how the theoretical analysis preceding the numerical
calculations helps to calculate the energy of the ground state of helium atom,
and enables to avoid qualitative errors in the calculations of the
characteristics of the double photoionization.


title:
Experimental evidence of spontaneous symmetry breaking in intracavity
  type-II second harmonic generation with triple resonance

abstract:
  We describe an experiment showing a spontaneous symmetry breaking phenomenon
between the intensities of the ordinary and extraordinary components of the
fundamental field in intracavity type-II harmonic generation. It is based on a
triply resonant dual cavity containing a type II phase matched $\chi^{(2)}$
crystal pumped at the fundamental frequency $\omega_0$. The pump beam generates
in the cavity a second harmonic mode at frequency $2\omega_0$ which acts as a
pump for frequency degenerate type II parametric down conversion. Under
operating conditions which are precisely symmetric with respect to the ordinary
and extraordinary components of the fundamental wave, we have observed a
breaking of the symmetry on the intensities of these two waves in agreement
with the theoretical predictions.


title: Nonlinear Rupture of Thin Liquid Films on Solid Surfaces

abstract:
  In this Letter we investigate the rupture instability of thin liquid films by
means of a bifurcation analysis in the vicinity of the short-scale instability
threshold. The rupture time estimate obtained in closed form as a function of
the relevant dimensionless groups is in striking agreement with the results of
the numerical simulations of the original nonlinear evolution equations. This
suggests that the weakly nonlinear theory captures the adequate physics of the
instability. When antagonistic (attractive/repulsive) molecular forces are
considered, nonlinear saturation of the instability becomes possible. We show
that the stability boundaries are determined by the van der Waals potential
alone.


title:
Effects of T2 Relaxation and Diffusion on Longitudinal Magnetization
  State and Signal Build for HOMOGENIZED Cross Peaks

abstract:
  An analytical expression has been developed to describe the effects of T2
relaxation and diffusing spatially modulated longitudinal spins during the
signal build period of an HOMOGENIZED cross peak. Diffusion of the longitudinal
spins results in a lengthening of the effective dipolar demagnetization time,
delaying the re-phasing of coupled anti-phase states in the quantum picture. In
the classical picture the unwinding rate of spatially twisted magnetization is
no longer constant, but decays exponentially with time. The expression is
experimentally verified for the HOMOGENIZED spectrum of 100mM TSP in H2O at
4.7T.
  More Keywords: magnetic resonance spectroscopy, MRS, intermolecular multiple
quantum coherence, iMQC, intermolecular zero quantum coherence, iZQC, distant
dipolar field, DDF


title:
Optical extinction due to intrinsic structural variations of photonic
  crystals

abstract:
  Unavoidable variations in size and position of the building blocks of
photonic crystals cause light scattering and extinction of coherent beams. We
present a new model for both 2 and 3-dimensional photonic crystals that relates
the extinction length to the magnitude of the variations. The predicted lengths
agree well with our new experiments on high-quality opals and inverse opals,
and with literature data analyzed by us. As a result, control over photons is
limited to distances up to 50 lattice parameters ($\sim 15 \mu$m) in
state-of-the-art structures, thereby impeding large-scale applications such as
integrated circuits. Conversely, scattering in photonic crystals may lead to
novel physics such as Anderson localization and non-classical diffusion.


title:
Reconstruction of spatially inhomogeneous dielectric tensors via optical
  tomography

abstract:
  A method to reconstruct weakly anisotropic inhomogeneous dielectric tensors
inside a transparent medium is proposed. The mathematical theory of Integral
Geometry is cast into a workable framework which allows the full determination
of dielectric tensor fields by scalar Radon inversions of the polarization
transformation data obtained from six planar tomographic scanning cycles.
Furthermore, a careful derivation of the usual equations of integrated
photoelasticity in terms of heuristic length scales of the material
inhomogeneity and anisotropy is provided, making the paper a self-contained
account about the reconstruction of arbitrary three-dimensional, weakly
anisotropic dielectric tensor fields.

categories: physics.optics cond-mat.mtrl-sci physics.ins-det quant-ph


title:
Radiostrontium activity concentrations in milk in the Republic of
  Croatia for 1961 - 2001 and dose assessment

abstract:
  Results of systematic measurements of Sr-90 activity concentrations in milk
for the period 1961 - 2001 are summarized. An exponential decline of
radioactivity followed the moratorium on atmospheric nuclear testing. The
highest activity of Sr-90 deposited by fallout, being 1060 Bq/m2, was recorded
in 1963, while the peak Sr-90 activity concentration in milk, 1.42 +/-0.17
Bq/L, was recorded in 1964. The values in year 2001 for fallout deposition and
milk were 7.7 Bq/m2 and 0.07 +/- 0.03 Bq/L, respectively. The reactor accident
at Chernobyl caused higher Sr-90 levels only in 1986. Sr-90 fallout activity
affects milk activity, the coefficient of correlation between Sr-90 fallout
activity and Sr-90 activity concentrations in milk being 0.80. The transfer
coefficient from fallout deposition to milk was estimated to be 2.5 mBqy/L per
Bq/m2. The dose incurred by milk consumption was estimated for the Croatian
population, the annual collective effective dose in 2001 being approximately
2.0 man-Sv.


title: A Simple Denoising Technique

abstract:
  The measurements of very low level signals at low frequency is a very
difficult problem, because environmental noise increases in this frequency
domain and it is very difficult to filter it efficiently. In order to
counteract these major problems, we propose a simple and generic denoising
technique, which mixes several features of traditional feedback techniques and
those of noise estimators. As an example of application, large band
measurements of the thermal fluctuations of a mechanical oscillator are
presented. These measurements show that the proposed denoising technique is
easy to implement and gives good results.


title: A re-examination of Maxwell's electromagnetic equations

abstract:
  It is pointed out that the usual derivation of the well-known Maxwell
electromagnetic equations holds only for a medium at rest. A way in which the
equations may be modified for the case when the mean flow of the medium is
steady and uniform is proposed. The implication of this for the problem of the
origin of planetary magnetic fields is discussed.


title: Coherent control of atom dynamics in an optical lattice

abstract:
  On the basis of a simple exactly solvable model we discuss the possibilities
for state preparation and state control of atoms in a periodic optical
potential. In addition to the periodic potential a uniform force with an
arbitrary time dependence is applied. The method is based on a formal
expression for the full evolution operator in the tight-binding limit. This
allows us to describe the dynamics in terms of operator algebra, rather than in
analytical expansions.


title:
Generic theory of active polar gels: a paradigm for cytoskeletal
  dynamics

abstract:
  We develop a general theory for active viscoelastic materials made of polar
filaments. This theory is motivated by the dynamics of the cytoskeleton. The
continuous consumption of a fuel generates a non equilibrium state
characterized by the generation of flows and stresses. Our theory can be
applied to experiments in which cytoskeletal patterns are set in motion by
active processes such as those which are at work in cells.


title:
Canonical description of ideal magnetohydrodynamic flows and integrals
  of motion

abstract:
  In the framework of the variational principle the canonical variables
describing ideal magnetohydrodynamic (MHD) flows of general type (i.e., with
spatially varying entropy and nonzero values of all topological invariants) are
introduced. The corresponding complete velocity representation enables us not
only to describe the general type flows in terms of single-valued functions,
but also to solve the intriguing problem of the ``missing'' MHD integrals of
motion. The set of hitherto known MHD local invariants and integrals of motion
appears to be incomplete: for the vanishing magnetic field it does not reduce
to the set of the conventional hydrodynamic invariants. And if the MHD analogs
of the vorticity and helicity were discussed earlier for the particular cases,
the analog of Ertel invariant has been so far unknown. It is found that on the
basis of the new invariants introduced a wide set of high-order invariants can
be constructed. The new invariants are relevant both for the deeper insight
into the problem of the topological structure of the MHD flows as a whole and
for the examination of the stability problems. The additional advantage of the
proposed approach is that it enables one to deal with discontinuous flows,
including all types of possible breaks.


title: Theoretical results on the Universe structure

abstract:
  This paper discusses an ordinary homogeneous differential equation of the
second order with constant real-valued coefficients. The solution of this
equation has to satisfy additional conditions. The first of the conditions
stems from the analytical research results of numerous scientists and many
years of astronomic observations confirming the stability of the celestial body
motion. This paper discusses only an asymptotically stable solution. The second
condition is based on the fact that nature does not know of such notions as
left or right, up or down. Consequently, the solution for positive time is
reflected with respect to negative time, i.e. an even function is obtained for
time from minus to plus infinity. That solution has an important physical
meaning, which can be ascribed to it based on the known Khinchin's theorem. It
changes radically the idea of the Universe composition and the processes taking
place in it.


title:
Relativistic least action principle for discontinuous hydrodynamic
  flows, Hamiltonian variables, helicity and Ertel invariant

abstract:
  A rigorous method for introducing the variational principle describing
relativistic ideal hydrodynamic flows with all possible types of breaks
(including shocks) is presented in the framework of an exact Clebsch type
representation of the four-velocity field as a bilinear combination of the
scalar fields. The boundary conditions for these fields on the breaks are
found. We also discuss the local invariants caused by the symmetries of the
problem, including relabeling symmetry. In particular, the generalization of
the well-known nonrelativistic Ertel invariant is presented.


title:
Quantitative Approach to Intensity-Modulated Radiation Therapy Quality
  Assurance Based on Film Dosimetry and Optimization

abstract:
  To accurately verify the dose of intensity-modulated radiation therapy
(IMRT), we have used a global optimization method to investigate a new
dose-verification algorithm. In practical application of this quality assurance
(QA) procedure, verification of the dose using calculated and measured dose
distributions involves a subtle problem in the region of high dose gradient.
Consideration of systematic errors shows that the large dose differences in
high-dose-gradient regions are due to the unexpected shift of measuring
devices. We have proposed an optimization algorithm to correct this error, and
an optimization method to minimize the average dose difference has been used in
this study. The relationship between the dose-verification procedure and the
applied optimization algorithm is explained precisely. Optimization
dramatically reduced the difference between measured and calculated dose
distributions in all cases investigated. The obtained results support the
relevance of our explanations for the problem in the high-dose-gradient region.
We have described this dose-verification procedure for IMRT and
intensity-modulated radiosurgery. Through this study we have also developed an
intuitive reporting method that is statistically reasonable.


title:
Three species collisionless reconnection: Effect of O+ on magnetotail
  reconnection

abstract:
  The nature of collisionless reconnection in a three-species plasma composed
of a heavy species, protons, and electrons is examined. Besides the usual two
length scales present in two-species reconnection, there are two additional
larger length scales in the system: one associated with a "heavy whistler"
which produces a large scale quadrupolar out-of-plane magnetic field, and one
associated with the "heavy Alfven" wave which can slow the outflow speed and
thus the reconnection rate. The consequences for reconnection in the
magnetotail with an O+ population present are discussed.


title:
Femtosecond laser as a tool for experimental study of inequality of
  forward and reversed processes in optics

abstract:
  The classical pump-probe scheme for experiments with femtosecond laser is
proposed to use for study the inequality of forward and reversed transitions in
optics.


title:
Precise Variational Calculation For The Doubly Excited State (2p^2)^3P^e
  of Helium

abstract:
  Highly precise variational calculations of non-relativistic energies of the
(2p^2)^3P^e state of Helium atom are presented.We get an upper bound energy
E=-0.71050015565678 a.u.,the lowest yet obtained.


title: An Algorithm for Computing Screened Coulomb Scattering in Geant4

abstract:
  An algorithm has been developed for the Geant4 Monte-Carlo package for the
efficient computation of screened Coulomb interatomic scattering. It explicitly
integrates the classical equations of motion for scattering events, resulting
in precise tracking of both the projectile and the recoil target nucleus. The
algorithm permits the user to plug in an arbitrary screening function, such as
Lens-Jensen screening, which is good for backscattering calculations, or
Ziegler-Biersack-Littmark screening, which is good for nuclear straggling and
implantation problems. This will allow many of the applications of the TRIM and
SRIM codes to be extended into the much more general Geant4 framework where
nuclear and other effects can be included.


title: Radiation shielding calculations for MuCool Test Area at Fermilab

abstract:
  The MuCool Test Area (MTA) is an intense primary beam facility derived
directly from the Fermilab Linac to test heat deposition and other technical
concerns associated with the liquid hydrogen targets being developed for
cooling intense muon beams. In this shielding study the results of Monte Carlo
radiation shielding calculations performed using the MARS14 code for the MuCool
Test Area and including the downstream portion of the target hall and berm
around it, access pit, service building, and parking lot are presented and
discussed within the context of the proposed MTA experimental configuration.


title: Resonant light interaction with plasmonic nanowire systems

abstract:
  We compare the optical response of isolated nanowires, double-wire systems,
and Pi-structures, and show that their radiation is well described in terms of
their electric and magnetic dipole moments. We also show that both dielectric
permittivity and magnetic permeability can be negative at optical and near
infrared frequencies, and demonstrate the connection between the geometry of
the system and its resonance characteristics. We conclude that plasmonic
nanowires can be employed for developing novel negative-index materials.
Finally, we demonstrate that it is possible to construct a nanowire-based
"transparent nanoresonator" with dramatically enhanced intensity and metal
concentration below 5 %.


title:
Error Probability of DPSK Signals with Intrachannel Four-Wave-Mixing in
  Highly Dispersive Transmission Systems

abstract:
  A semi-analytical method evaluates the error probability of DPSK signals with
intrachannel four-wave-mixing (IFWM) in a highly dispersive fiber link with
strong pulse overlap. Depending on initial pulse width, the mean nonlinear
phase shift of the system can be from 1 to 2 rad for signal-to-noise ratio
(SNR) penalty less than 1 dB. An approximated empirical formula, valid for
penalty less than 2 dB, uses the variance of the differential phase of the
ghost pulses to estimate the penalty.


title: Anisotropy of x-ray scattering in aligned nanotube structures

abstract:
  Effects of orientational x-ray scattering have been experimentally examined
in a film of vertically aligned multiwall carbon nanotubes (CNs). Additional
contribution to the x-ray fluorescence intensity was revealed at angles close
to the film normal. Theoretical considerations suggest the intensity
enhancement to be caused by propagation of C K$_{\alpha}$-radiation mainly
along the channels of CNs.


title:
Analytical expressions for optimum alignment modes of highly segmented
  mirrors

abstract:
  The major sources causing deterioration of optical quality in extremely large
optical telescopes are misadjustments of the mirrors, deformations of
monolithic mirrors, and misalignments of segments in segmented mirrors. For
active optics corrections, all three errors, which can partially compensate
each other, are measured simultaneously. It is therefore of interest to
understand the similarities and differences between the three corresponding
types of modes which describe these errors. The first two types are best
represented by Zernike polynomials and elastic modes respectively, both of them
being continuous and smooth functions. The segment misaligment modes, which are
derived by singular value decomposition, are by their nature not smooth and in
general discontinuous. However, for mirrors with a large number of segments,
the lowest modes become effectively both smooth and continuous. This paper
derives analytical expressions for these modes, using differential operators
and their adjoints, for the limit case of infinitesimally small segments. For
segmented mirrors with approximately 1000 segments, it is shown that these
modes agree well with the corresponding lowest singular value decomposition
modes. Furthermore, the analytical expressions reveal the nature of the segment
misalignment modes and allow for a detailed comparison with the elastic modes
of monolithic mirrors. Some mathematical features emerge as identical in the
two cases.


title: Quantization Rules for Bound States of the Schr\"{o}dinger Equation

abstract:
  An exact quantization rule for the bound states of the one-dimensional
Schr\"{o}dinger equation is presented and is generalized to the
three-dimensional Schr\"{o}dinger equation with a spherically symmetric
potential.


title:
Laser-induced splittings in the nuclear magnetic resonance spectra of
  the rare gases

abstract:
  Circularly polarized laser field causes a shift in the nuclear magnetic
resonance (NMR) spectra of all substances. The shift is proportional to the
intensity of the laser beam and yields oppositely signed values for left- and
right-circularly polarized light, CPL -/+, respectively. Rapid switching -- in
the NMR time scale -- between CPL+ and CPL- gives rise to a splitting of the
NMR resonance lines. We present uncorrelated and correlated quadratic response
calculations of the splitting per unit of beam intensity in the NMR spectra of
$^{21}$Ne, $^{83}$Kr, and $^{129}$Xe. We study both the regions far away from
and near to optical resonance and predict off-resonance shifts of the order
0.01, 0.1, and $1\times 10^{-6}$ Hz for $^{21}$Ne, $^{83}$Kr, and $^{129}$Xe,
respectively, for a beam intensity of 10 W/cm$^2$. Enhancement by several
orders of magnitude is predicted as the beam frequency approaches resonance.
Only then can the effect on guest $^{129}$Xe atoms be potentially useful as a
probe of the properties of the host material.


title:
New Directions in Degenerate Dipolar Molecules via Collective
  Association

abstract:
  We survey results on the creation of heteronuclear Fermi molecules by tuning
a degenerate Bose-Fermi mixture into the neighborhood of an association
resonance, either photoassociation or Feshbach, as well as the subsequent
prospects for Cooper-like pairing between atoms and molecules. In the simplest
case of only one molecular state, corresponding to either a Feshbach resonance
or one-color photoassociation, the system displays Rabi oscillations and rapid
adiabatic passage between a Bose-Fermi mixture of atoms and fermionic
molecules. For two-color photoassociation, the system admits stimulated Raman
adiabatic passage (STIRAP) from a Bose-Fermi mixture of atoms to stable Fermi
molecules, even in the presence of particle-particle interactions. By tailoring
the STIRAP sequence it is possible to deliberately convert only a fraction of
the initial atoms, leaving a finite fraction of bosons behind to induce
atom-molecule Cooper pairing via density fluctuations; unfortunately, this
enhancement is insufficient to achieve a superfluid transition with present
ultracold technology. We therefore propose the use of an association resonance
that converts atoms and diatomic molecules (dimers) into triatomic molecules
(trimers), which leads to a crossover from a Bose-Einstein condensate of
trimers to atom-dimer Cooper pairs. Because heteronuclear dimers may possess a
permanent electric dipole moment, this overall system presents an opportunity
to investigate novel microscopic physics.

categories: physics.atom-ph cond-mat.soft cond-mat.supr-con physics.chem-ph quant-ph


title: Current-Voltage Relations for Electrochemical Thin Films

abstract:
  The dc response of an electrochemical thin film, such as the separator in a
micro-battery, is analyzed by solving the Poisson-Nernst-Planck equations,
subject to boundary conditions appropriate for an electrolytic/galvanic cell.
The model system consists of a binary electrolyte between parallel-plate
electrodes, each possessing a compact Stern layer, which mediates Faradaic
reactions with nonlinear Butler-Volmer kinetics. Analytical results are
obtained by matched asymptotic expansions in the limit of thin double layers
and compared with full numerical solutions. The analysis shows that (i)
decreasing the system size relative to the Debye screening length decreases the
voltage of the cell and allows currents higher than the classical
diffusion-limited current; (ii) finite reaction rates lead to the important
possibility of a reaction-limited current; (iii) the Stern-layer capacitance is
critical for allowing the cell to achieve currents above the reaction-limited
current; and (iv) all polarographic (current-voltage) curves tend to the same
limit as reaction kinetics become fast. Dimensional analysis, however, shows
that ``fast'' reactions tend to become ``slow'' with decreasing system size, so
the nonlinear effects of surface polarization may dominate the dc response of
thin films.


title: Electrochemical Thin Films At and Above the Classical Limiting Current

abstract:
  We study a model electrochemical thin film at dc currents exceeding the
classical diffusion-limited value. The mathematical problem involves the steady
Poisson-Nernst-Planck equations for a binary electrolyte with nonlinear
boundary conditions for reaction kinetics and Stern-layer capacitance, as well
as an integral constraint on the number of anions. At the limiting current, we
find a nested boundary layer structure at the cathode, which is required by the
reaction boundary condition. Above the limiting current, a depletion of anions
generally characterizes the cathode side of the cell. In this regime, we derive
leading-order asymptotic approximations for the (i) classical bulk space-charge
layer and (ii) another, nested highly charged boundary layer at the cathode.
The former involves an exact solution to the Nernst-Planck equations for a
single, unscreened ionic species, which may apply more generally to Faradaic
conduction through very thin insulating films. By matching expansions, we
derive current-voltage relations well into the space-charge regime. Throughout
our analysis, we emphasize the strong influence of the Stern-layer capacitance
on cell behavior.


title:
Collective molecule formation in a degenerate Fermi gas via a Feshbach
  resonance

abstract:
  We model collisionless collective conversion of a degenerate Fermi gas into
bosonic molecules via a Feshbach resonance, treating the bosonic molecules as a
classical field and seeding the pairing amplitudes with random phases. A
dynamical instability of the Fermi sea against association into molecules
initiates the conversion. The model qualitatively reproduces several
experimental observations {[Regal et al., Nature {\bf 424}, 47 (2003)]}. We
predict that the initial temperature of the Fermi gas sets the limit for the
efficiency of atom-molecule conversion.

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


title: An easy way to Gravimagnetism

abstract:
  One of the numerous results of the Theory of General Relativity is the
appearance of Gravimagnetism, described already by Thirring and Lense in 1918
[THI 18]. Its understanding normally remains reserved to specialists.
  This article presents a simple classical analogy to bring the description of
Gravimagnetism within the reach of beginners. The article describes a classical
model calculation on the level of undergraduate students and mentions the
situation of the modern experiment.


title: Feyerabend and physics

abstract:
  Feyerabend frequently discussed physics. He also referred to the history of
the subject when motivating his philosophy of science. Alas, as some examples
show, his understanding of physics remained superficial. In this respect,
Feyerabend is like Popper; the difference being his self-criticism later on,
and the much more tolerant attitude toward the allowance of methods. Quite
generally, partly due to the complexity of the formalism and the new challenges
of their findings, which left philosophy proper at a loss, physicists have
attempted to developed their own meaning of their subject. For instance, in
recent years, the interpretation of quantum mechanics has stimulated a new type
of experimental philosophy, which seeks to operationalize emerging
philosophical issues; issues which are incomprehensible for most philosophers.
In this respect, physics often appears to be a continuation of philosophy by
other means. Yet, Feyerabend has also expressed profound insights into the
possibilities for the progress of physics, a legacy which remains to be
implemented in the times to come: the conquest of abundance, the richness of
reality, the many worlds which still await discovery, and the vast openness of
the physical universe.


title: Model And Fabrication Of A Proof-Of-Concept Polarimeter-In-A-Pixel

abstract:
  I propose a new optoelectronic device that completely and instantaneously
measures the incident light's polarization for a narrow wavelength band in a
single physical pixel. The device has four (or more) quantum-well active
regions separated and topped by four (or more) linear gratings at different
orientations. Electrical contact is made to each grating and to a bottom
contact layer to measure four (or more) photocurrents. The device uses
interference among many light paths to encode in four photocurrents four values
that completely describe the polarization state of the incident light at a
given wavelength. I begin with the motivation for the new device. Then, I
report on two computational models: the first includes perfectly conducting
gratings, and the second includes more realistic dielectric gratings. Next, I
will describe the design and processing of a two-layer proof-of-concept device.
Last, I will recount the trials of the first round of fabrication.


title:
Adaptive Dispersion Compensation for Remote Fiber Delivery of NIR
  Femtosecond Pulses

abstract:
  We report on remote delivery of 25 pJ broadband near-infrared femtosecond
light pulses from a Ti:sapphire laser through 150 meters of single-mode optical
fiber. Pulse distortion due to dispersion is overcome with pre-compensation
using adaptive pulse shaping techniques, while nonlinearities are mitigated
using an SF10 rod for the final stage of pulse compression. Near transform
limited pulse duration of 130 fs is measured after the final compression.


title: Rotational cooling of molecules using lamps

abstract:
  We investigate theoretically the application of tailored incoherent
far-infrared fields in combination with laser excitation of a single
rovibrational transition for rotational cooling of translationally cold polar
diatomic molecules. The cooling schemes are effective on a timescale shorter
than typical unperturbed trapping times in ion traps and comparable to
obtainable confinement times of neutral molecules.


title:
Accurate calculations of magnetic dipole and electric quadrupole
  hyperfine coupling constants of 6 P_{3/2} state of Cesium atom : A
  Relativistic Coupled Cluster approach

abstract:
  We report the magnetic dipole and electric quadrupole hyperfine coupling
constants of 6 P_{3/2} state of ^{133} Cs(I= {7/2}) obtained from the
relativistic coupled cluster (RCC) method. To our knowledge, no prior electric
quadrupole hyperfine CC calculation is available for ^{133} Cs(6 P_{3/2})
state. Our computed magnetic dipole (A) and electric quadrupole (B) coupling
constants are in excellent agreement with the experiment.