title:
Seismic Rayleigh waves on an exponentially graded, orthotropic
  half-space

abstract:
  Efforts at modelling the propagation of seismic waves in half-spaces with
continuously varying properties have been mostly focused on shear-horizontal
waves. Here a sagittaly polarized (Rayleigh type) wave travels along a symmetry
axis (and is attenuated along another) of an orthotropic material with
stiffnesses and mass density varying in the same exponential manner with depth.
Contrary to what could be expected at first sight, the analysis is very similar
to that of the homogeneous half-space, with the main and capital difference
that the Rayleigh wave is now dispersive. The results are illustrated
numerically for (i) an orthotropic half-space typical of horizontally layered
and vertically fractured shales and (ii) for an isotropic half-space made of
silica. In both examples, the wave travels at a slower speed and penetrates
deeper than in the homogeneous case; in the second example, the inhomogeneity
can force the wave amplitude to oscillate as well as decay with depth, in
marked contrast with the homogeneous isotropic general case.


title: Gravitational potential, inertia and Earth rotation

abstract:
  Several satellite missions, devoted to the study of the Earth gravity field,
have been launched (like CHAMP, recently). This year, GRACE (Gravity Recovery
and Climate Experiment) will allow us to obtain a more precise geoid. But the
most important is that they will supply the temporal variations of the
geopotential coefficients (called Stokes coefficients). In the poster we show
how the Earth gravitational potential is linked to the Earth rotation
parameters. Indeed, through the Earth inertia coefficients, we can connect the
variation of LOD and Polar Motion with the temporal variations of the Stokes
coefficients. We also consider the nutations, that are related to the
gravitational geopotential coefficients. We discuss the possibility of using
the Stokes coefficients in order to improve our knowledge of the Earth
rotation.


title:
Measurement of Isolated Photon Production in Deep-Inelastic Scattering
  at HERA

abstract:
  The production of isolated photons in deep-inelastic scattering $ep\to e
\gamma X$ is measured with the H1 detector at HERA. The measurement is
performed in the kinematic range of negative four-momentum transfer squared
$4<Q^2<150 $~GeV$^2$ and a mass of the hadronic system $W_X>50$ GeV. The
analysis is based on a total integrated luminosity of 227~pb$^{-1}$. The
production cross section of isolatedphotons with a transverse energy in the
range $3 < E_T^\gamma < 10$ GeV and pseudorapidity range $-1.2 < \eta^\gamma <
1.8$ is measured as a function of $E_T^\gamma$, $\eta^\gamma$ and $Q^2$.
Isolated photon cross sections are also measured for events with no jets or at
least one hadronic jet. The measurements are compared with predictions from
Monte Carlo generators modelling the photon radiation from the quark and the
electron lines, as well as with calculations at leading and next to leading
order in the strong coupling. The predictions significantly underestimate the
measured cross sections.


title: Temporal variations of the gravity field and Earth precession-nutation

abstract:
  Due to the accuracy now reached by space geodetic techniques, and also
considering some modelisations, the temporal variations of some Earth Gravity
Field coefficients can be determined. They are due to Earth oceanic and solid
tides, as well as geophysical reservoirs masses displacements. They can be
related to the variations in the Earth's orientation parameters (through the
inertia tensor). Then, we can try to improve our knowledge of the Earth
Rotation with those space measurements of the Gravity variations. We have
undertaken such a study, using data obtained with the combination of space
geodetic techniques. In particular, we use CHAMP data that are more sensitive
to such variations and that complete the ones already accumulated (for example
with Starlette and LAGEOS I). In this first approach, we focus on the Earth
precession nutation, trying to refine it by taking into account the temporal
variations of the Earth dynamical flattening. The goal is mainly to understand
how Geodesy can influence this field of science. Like this, we will be able to
compare our computation with up to date determinations of precession nutation.


title: Thermodiffusion in model nanofluids by molecular dynamics simulations

abstract:
  In this work, a new algorithm is proposed to compute single particle
(infinite dilution) thermodiffusion using Non-Equilibrium Molecular Dynamics
simulations through the estimation of the thermophoretic force that applies on
a solute particle. This scheme is shown to provide consistent results for
simple Lennard-Jones fluids and for model nanofluids (spherical non-metallic
nanoparticles + Lennard-Jones fluid) where it appears that thermodiffusion
amplitude, as well as thermal conductivity, decrease with nanoparticles
concentration. Then, in nanofluids in the liquid state, by changing the nature
of the nanoparticle (size, mass and internal stiffness) and of the solvent
(quality and viscosity) various trends are exhibited. In all cases the single
particle thermodiffusion is positive, i.e. the nanoparticle tends to migrate
toward the cold area. The single particle thermal diffusion 2 coefficient is
shown to be independent of the size of the nanoparticle (diameter of 0.8 to 4
nm), whereas it increases with the quality of the solvent and is inversely
proportional to the viscosity of the fluid. In addition, this coefficient is
shown to be independent of the mass of the nanoparticle and to increase with
the stiffness of the nanoparticle internal bonds. Besides, for these
configurations, the mass diffusion coefficient behavior appears to be
consistent with a Stokes-Einstein like law.


title:
Length of day and polar motion, with respect to temporal variations of
  the Earth gravity field

abstract:
  The masses distribution inside the Earth governs the behaviour of the
rotation axis in the Earth (polar motion), as well as the Earth rotation rate
(or equivalently, length of day). This masses distribution can be measured from
space owing to artificial satellites, the orbitography of which provides the
Earth gravity field determination. Then, the temporal variations of the Earth
gravity field can be related to the variations of the Earth Orientation
Parameters (EOP) (with the Inertia Tensor). Nowadays, owing to the satellite
laser ranging (SLR) technique and to the new gravimetric satellite missions
(such as CHAMP or GRACE), the temporal variations of the low degree
coefficients of the Earth gravity field (i.e. Stokes coefficients) can be
determined. This paper is one of the first study using gravity variations data
in the equations already established (e.g. Lambeck 1988) and linking the
variations of the length of day and of the C20 Stokes coefficient (or, linking
the polar motion and the C21 and S21 coefficients). This paper combines the
Earth rotation data (mainly obtained from VLBI and GPS measurements) and the
Earth gravity field variations ones (e.g. Lageos I and II data, or GRACE data),
in order to complete and constrain the models of the Earth rotation. The final
goal is a better Earth global dynamics understanding, which possible
application can be the constraint on the couplings into the Earth system (e.g.
core-mantle couplings).


title:
Earth rotation and variations of the gravity field, in the framework of
  the "Descartes-nutation" project

abstract:
  The "Descartes-Nutation" Project is devoted to the "understanding of the next
decimal of precession-nutation, from the theoretical point of view as well as
from the observational point of view". In this framework, we made a proposal in
order to contribute to the study of (i) the dynamical flattening of the Earth,
(ii) the coupling effects of the lunisolar forcing, (iii) the effect of the
geophysical fluids on the EOP and (iv) the Nutation observations. We
investigate further the links between Earth Orientation and Gravity Field
Variations. Indeed, the masses distributions inside the Earth govern the
behaviour of the rotation axis in space (precession-nutation) and in the Earth
(polar motion), as well as the Earth rotation rate (or equivalently, length of
the day). These distributions of masses can be measured by space owing to
artificial satellites, the orbitography of which provides the Earth gravity
field determination. Then, the temporal variations of the Earth gravity field
can be related to the variations of the Earth Orientation Parameters (EOP)
(with the Inertia Tensor). Nowadays, the Earth orientation measurements in
space, obtained with Very Long Baseline Interferometry (VLBI), have a precision
better than the milliarcsecond level. It is then necessary to consider all the
geophysical sources that can improve the models precision. The goal of my PhD
Thesis was to use the Earth gravity field measurements, as well as its
variations, as a tool to improve the Earth orientation modelisation. We present
here the results obtained as well as various proposals to extend these
investigations (numerical studies, the use of J2 geophysical series,
integration of GRACE data ...).


title:
Temperature and Humidity Dependence of Air Fluorescence Yield measured
  by AIRFLY

abstract:
  The fluorescence detection of ultra high energy cosmic rays requires a
detailed knowledge of the fluorescence light emission from nitrogen molecules
over a wide range of atmospheric parameters, corresponding to altitudes typical
of the cosmic ray shower development in the atmosphere. We have studied the
temperature and humidity dependence of the fluorescence light spectrum excited
by MeV electrons in air. Results for the 313.6 nm, 337.1 nm, 353.7 nm and 391.4
nm bands are reported in this paper. We found that the temperature and humidity
dependence of the quenching process changes the fluorescence yield by a
sizeable amount (up to 20%) and its effect must be included for a precise
estimation of the energy of ultra high energy cosmic rays.


title: Earth Orientation and Temporal Variations of the Gravity Field

abstract:
  The high accuracy now reached in the VLBI Earth Orientation Parameters (EOP)
determination requires looking further at the various geophysical contributions
to variations in EOP. The determination of the Earth gravity field from space
geodetic techniques now allows us to obtain the temporal variations of the low
degree coefficients of the geopotential, combining the treatment of different
satellites (e.g. Lageos1, Lageos2, Starlette ...). We present a new computation
of the degree 2 coefficients of the variable Earth gravity field. This study is
based upon the using of (i) new orbit standards, (ii) the GRACE mean gravity
field and (iii) Lageos1 data from 1985 until 2004 (merged with Lageos2 data
from 1993). These temporal variations of the Earth gravity field can be related
to the Earth Orientation Parameters through the inertia tensor. This paper
shows these relations and discusses how such geodetic data can contribute to
the understanding of the variations in EOP. This paper also studies if these
refined 20-yr of Lageos data can give us refined value of the 18.6-yr tidal
term, as well as of the secular drift of the C20 geopotential coefficient.


title: Prevalence of marginally unstable periodic orbits in chaotic billiards

abstract:
  The dynamics of chaotic billiards is significantly influenced by coexisting
regions of regular motion. Here we investigate the prevalence of a different
fundamental structure, which is formed by marginally unstable periodic orbits
and stands apart from the regular regions. We show that these structures both
{\it exist} and {\it strongly influence} the dynamics of locally perturbed
billiards, which include a large class of widely studied systems. We
demonstrate the impact of these structures in the quantum regime using
microwave experiments in annular billiards.


title: Epitaxial influence on the ferromagnetic semiconducotor EuO

abstract:
  From first principles calculations we investigate the electronic structure
and the magnetic properties of EuO under hydrostatic and epitaxial forces.
There is a complex interdependence of the O 2p and Eu 4f and 5d bands on the
magnetism in EuO, and decreasing lattice parameters is an ideal method to
increase the Curie temperature, T_c. Compared to hydrostatic pressure, the
out-of-plane compensation that is available to epitaxial films influences this
increase in T_c, although it is minimized by the small value of poisson's ratio
for EuO. We find the semiconducting gap closes at a 6% in-plane lattice
compression for epitaxy, at which point a significant conceptual change must
occur in the active exchange mechanisms.


title: The survival of dark matter halos in the cluster Cl0024+16

abstract:
  Theories of structure formation in a cold dark matter dominated
  Universe predict that massive clusters of galaxies assemble from the
hierarchical merging of lower mass subhalos. Exploiting strong and weak
gravitational lensing signals inferred from panoramic HST imaging data, we
present a high resolution reconstruction of the mass distribution in the
massive, lensing cluster Cl0024+16. Applying galaxy-galaxy lensing techniques
we track the fate of dark matter subhalos as a function of projected
cluster-centric radius out to 5 Mpc, well beyond the virial radius. We report
the first detection of the statistical lensing signal of dark matter subhalos
associated with late-type galaxies in clusters. The mass of a typical dark
matter subhalo that hosts an L* galaxy increases with projected cluster-centric
radius in line with expectations from the tidal stripping hypothesis.
Early-type galaxies appear to be hosted on average in more massive dark matter
subhalos compared to late-type galaxies. We interpret our findings as evidence
for the active assembly of mass via tidal stripping in galaxy clusters. The
mass function of dark matter subhalos as a function of projected
cluster-centric radius, is compared with an equivalent mass function derived
from clusters in the Millenium Run simulation populated with galaxies using
semi-analytic models. The shape of the lensing determined mass functions are in
very good agreement with the subhalo mass functions derived from the Millenium
Run simulation. However, simulated subhalos appear to be more efficiently
stripped than lensing observations suggest. (Abridged)


title:
Kinematic and Chemical constraints on the formation of M31's inner and
  outer halo

abstract:
  The halo of M31 shows a wealth of substructures that are consistent with
satellite accretion. Here we report on kinematic and abundance results from
Keck/DEIMOS spectroscopy in the calcium triplet region of over 3500 red giant
star candidates along the minor axis and in off-axis spheroid fields of M31.
Our data reach out to large radial distances of 160 kpc. The derived velocity
distributions show a kinematically cold substructure at 17 kpc that has been
reported before. We devise an improved method to measure accurate metallicities
from the calcium triplet in low signal-to-noise spectra using a coaddition of
the individual lines. The resulting distribution leads us to note an even
stronger gradient in the abundance distribution along M31's minor axis than
previously detected. The mean metallicity in the outer halo reaches below -2
dex, with individual values as low as -2.6 dex. In the inner spheroid, at 17-19
kpc, we find a sharp decline of ~0.5 dex in metallicity, which roughly
coincides with the edge of an extended disk, previously detected from star
count maps. A large fraction of red giants in the most distant fields are
likely members of M33's overlapping halo. A comparison of our velocities with
those predicted by new N-body simulations argues that the event responsible for
the giant Stream is most likely not responsible for the full population of the
inner halo; we show further that the abundance distribution of the Stream is
different from that of the inner halo, from which it becomes evident that the
merger event that formed the outer halo cannot have contributed any significant
material to the inner spheroid. All this evidence of severe structure changes
in the halo suggests a high degree of infall and stochastic abundance accretion
governing the build-up of M31's halo. (Abridged)


title: The Once and Future Andromeda Stream

abstract:
  The interaction between an accreting satellite and the Andromeda galaxy (M31)
has been studied analytically and numerically, using a high-resolution N-body
simulation with $4\times10^7$ particles. For the first time, we show the
self-gravitating response of the disk, the bulge, and the dark matter halo of
M31 to an accreting satellite. We reproduce the Stream and the shells at the
East and West side of M31, by following the evolution of the collision 4 Gyr
into the future, and show that recently discovered diffuse arcs on the south
side of the minor axis are the remnants of a similar collision that occurred
3-4 Gyr earlier than the Stream event. The present day integrity of the M31
disk constrains the satellite mass to be $M \leq 5\times10^9 M_\odot$. The
stars that were originally in the center of the satellite are now in the east
shell. Therefore, observations in this region might reveal additional clues
about the nature of satellite, such as the central core and any metallicity
gradient.


title: Helioseismology and Solar Abundances

abstract:
  Helioseismology has allowed us to study the structure of the Sun in
unprecedented detail. One of the triumphs of the theory of stellar evolution
was that helioseismic studies had shown that the structure of solar models is
very similar to that of the Sun. However, this agreement has been spoiled by
recent revisions of the solar heavy-element abundances. Heavy element
abundances determine the opacity of the stellar material and hence, are an
important input to stellar model calculations. The models with the new, low
abundances do not satisfy helioseismic constraints. We review here how
heavy-element abundances affect solar models, how these models are tested with
helioseismology, and the impact of the new abundances on standard solar models.
We also discuss the attempts made to improve the agreement of the low-abundance
models with the Sun and discuss how helioseismology is being used to determine
the solar heavy-element abundance. A review of current literature shows that
attempts to improve agreement between solar models with low heavy-element
abundances and seismic inference have been unsuccessful so far. The
low-metallicity models that have the least disagreement with seismic data
require changing all input physics to stellar models beyond their acceptable
ranges. Seismic determinations of the solar heavy-element abundance yield
results that are consistent with the older, higher values of the solar
abundance, and hence, no major changes to the inputs to solar models are
required to make higher-metallicity solar models consistent with helioseismic
data.


title:
Light Higgses at the Tevatron and at the LHC and Observable Dark Matter
  in SUGRA and D Branes

abstract:
  Sparticle landscapes in mSUGRA, in SUGRA models with nonuniversalities
(NUSUGRA), and in D brane models are analyzed. The analysis exhibits the
existence of Higgs Mass Patterns (HPs) (for $\mu>0$) where the CP odd Higgs
could be the next heavier particle beyond the LSP and sometimes even lighter
than the LSP. It is shown that the Higgs production cross sections from the HPs
are typically the largest enhancing the prospects for their detection at the
LHC. Indeed it is seen that the recent Higgs production limits from CDF/D\O\
are beginning to put constraints on the HPs. It is also seen that the $B_s\to
\mu^+\mu^-$ limits constrain the HPs more stringently. Predictions of the Higgs
production cross sections for these patterns at the LHC are made. We compute
the neutralino-proton cross sections $\sigma (\chi p)$ for dark matter
experiments and show that the largest $\sigma (\chi p)$ also arise from the HPs
and further that the HPs and some of the other patterns are beginning to be
constrained by the most recent data from CDMS and from Xenon10 experiments.
Finally, it is shown that the prospects are bright for the discovery of dark
matter with $\sigma(\chi p)$ in the range $10^{-44\pm .5}$cm$^2$ due to a
"Wall" consisting of a copious number of parameter points in the Chargino
Patterns (CPs) where the chargino is the NLSP. The Wall, which appears in all
models considered (mSUGRA, NUSUGRA and D branes) and runs up to about a TeV in
LSP mass, significantly enhances the chances for the observation of dark matter
by SuperCDMS, ZEPLIN-MAX, or LUX experiments which are expected to achieve a
sensitivity of $10^{-45}$ cm$^2$ or more.


title:
Harmonic Functions, Entropy, and a Characterization of the Hyperbolic
  Space

abstract:
  Let $(M^{n},g)$ be a compact Riemannian manifold with $Ric\geq-(n-1) $. It is
well known that the bottom of spectrum $\lambda_{0}$ of its unverversal
covering satisfies $\lambda_{0}\leq(n-1) ^{2}/4 $. We prove that equality holds
iff $M$ is hyperbolic. This follows from a sharp estimate for the Kaimanovich
entropy.


title:
Spin asymmetries for elastic proton scattering and the spin dependent
  couplings of the Pomeron

abstract:
  This paper serves as a report on the large amount of analysis done in
conjunction with the polarized proton program at RHIC. This comprises elastic
scattering data of protons on protons in colliding beam or fixed target mode
and proton beams on carbon targets. In addition to providing a model for the
energy dependence of the analyzing power of elastic scattering needed for
proton polarimetry, it also provides some significant information about the
spin dependence of dominant Regge poles. Most notably, the data indicates that
the Pomeron has a significant spin-flip coupling. This allows the exploration
of the double spin flip asymmetry A_{NN} for which some data over a wide energy
range is now available, along with a concrete realization of a proposed Odderon
search.


title:
P-wave Pairing in Two-Component Fermi Systems with Unequal Population
  near Feshbach Resonance

abstract:
  We explore p-wave pairing in a single-channel two-component Fermi system with
unequal population near Feshbach resonance. Our analytical and numerical study
reveal a rich superfluid (SF) ground state structure as a function of
imbalance. In addition to the state $\Delta_{\pm 1} \propto Y_{1\pm 1}$, a
multitude of ``mixed'' SF states formed of linear combinations of $Y_{1m}$'s
give global energy minimum under a phase stability condition; these states
exhibit variation in energy with the relative phase between the constituent gap
amplitudes. States with local energy minimum are also obtained. We provide a
geometric representation of the states. A $T$=0 polarization vs. p-wave
coupling phase diagram is constructed across the BEC-BCS regimes. With
increased polarization, the global minimum SF state may undergo a quantum phase
transition to the local minimum SF state.


title: A Rigidity Theorem for the Hemisphere

abstract:
  We prove the following rigidity theorem: For an n-dimensional compact
Riemannian manifold with boundary whose Ricci curvature is bounded by n-1 from
below, if its boundary is isometric to the standard sphere of dimension n-1 and
totally geodesic, then the manifold is isometric to the standard hemisphere.


title:
The non-random walk of stock prices: The long-term correlation between
  signs and sizes

abstract:
  We investigate the random walk of prices by developing a simple model
relating the properties of the signs and absolute values of individual price
changes to the diffusion rate (volatility) of prices at longer time scales. We
show that this benchmark model is unable to reproduce the diffusion properties
of real prices. Specifically, we find that for one hour intervals this model
consistently over-predicts the volatility of real price series by about 70%,
and that this effect becomes stronger as the length of the intervals increases.
By selectively shuffling some components of the data while preserving others we
are able to show that this discrepancy is caused by a subtle but long-range
non-contemporaneous correlation between the signs and sizes of individual
returns. We conjecture that this is related to the long-memory of transaction
signs and the need to enforce market efficiency.


title:
Pinned distance sets, Wolff's exponent in finite fields and improved
  sum-product estimates

abstract:
  An analog of the Falconer distance problem in vector spaces over finite
fields asks for the threshold $\alpha>0$ such that $|\Delta(E)| \gtrsim q$
whenever $|E| \gtrsim q^{\alpha}$, where $E \subset {\Bbb F}_q^d$, the
$d$-dimensional vector space over a finite field with $q$ elements (not
necessarily prime). Here $\Delta(E)=\{{(x_1-y_1)}^2+...+{(x_d-y_d)}^2: x,y \in
E\}$. The second listed author and Misha Rudnev established the threshold
$\frac{d+1}{2}$, and the authors of this paper, Doowon Koh and Misha Rudnev
proved that this exponent is sharp in even dimensions. In this paper we improve
the threshold to $\frac{d^2}{2d-1}$ under the additional assumption that $E$
has product structure. In particular, we obtain the exponent 4/3, consistent
with the corresponding exponent in Euclidean space obtained by Wolff.


title: Dynamical Evolution of Globular Clusters in Hierarchical Cosmology

abstract:
  We probe the evolution of globular clusters that could form in giant
molecular clouds within high-redshift galaxies. Numerical simulations
demonstrate that the large and dense enough gas clouds assemble naturally in
current hierarchical models of galaxy formation. These clouds are enriched with
heavy elements from earlier stars and could produce star clusters in a similar
way to nearby molecular clouds. The masses and sizes of the model clusters are
in excellent agreement with the observations of young massive clusters. Do
these model clusters evolve into globular clusters that we see in our and
external galaxies? In order to study their dynamical evolution, we calculate
the orbits of model clusters using the outputs of the cosmological simulation
of a Milky Way-sized galaxy. We find that at present the orbits are isotropic
in the inner 50 kpc of the Galaxy and preferentially radial at larger
distances. All clusters located outside 10 kpc from the center formed in the
now-disrupted satellite galaxies. The spatial distribution of model clusters is
spheroidal, with a power-law density profile consistent with observations. The
combination of two-body scattering, tidal shocks, and stellar evolution results
in the evolution of the cluster mass function from an initial power law to the
observed log-normal distribution.


title:
How can we derive Fourier's Law from quantum mechanics? Exact master
  equation analysis

abstract:
  We derive the macroscopic Fourier's Law of heat conduction from the exact
gain-loss time convolutionless quantum master equation under three assumptions
for the interaction kernel. To second order in the interaction, we show that
the first two assumptions are natural results of the long time limit. The third
assumption can be satisfied by a family of interactions consisting an exchange
effect. The pure exchange model directly leads to energy diffusion in a weakly
coupled spin-1/2 chain.


title:
Localization and the interface between quantum mechanics, quantum field
  theory and quantum gravity

abstract:
  We show that there are significant conceptual differences between QM and QFT
which make it difficult to view the latter as just a relativistic extension of
the principles of QM. At the root of this is a fundamental distinction between
Born-localization in QM (which in the relativistic context changes its name to
Newton-Wigner localization) and modular localization which is the localization
underlying QFT, after one liberates it from its standard presentation in terms
of field coordinates. The first comes with a probability notion and projection
operators, whereas the latter describes causal propagation in QFT and leads to
thermal aspects of locally reduced finite energy states. The Born-Newton-Wigner
localization in QFT is only applicable asymptotically and the covariant
correlation between asymptotic in and out localization projectors is the basis
of the existence of an invariant scattering matrix. Taking these significant
differences serious has not only repercussions for the philosophy of science,
but also leads to a new structural properties as a consequence of vacuum
polarization: the area law for localization entropy near the the causal
localization horizon and a more realistic cutoff independent setting for the
cosmological vacuum energy density which is compatible with local covariance.
The article presents some observations about the interface between QFT in CST
and QG.


title:
Colossal Van der Waals small-polaron superlattice: a hint to
  understanding the colossal magnetoresistance and electroresistance in
  manganites

abstract:
  A mechanism is proposed to explain the formation of a small-polaron
superlattice above the Curie temperature in manganites. The order-disorder
transition initiated by the external field at a lattice is known responsible
for the colossal resistance effect. We attribute the lattice formation to the
occurrence of strong Van der Waals pairing of vibronic small polarons arising
from the phonon coupling of highly polarizable two-level orbital systems. The
latter having inherent electric and magnetic dipoles associated with them, they
couple to the external field leading to the observed colossal effects. We find
numerical estimates of the critical field compatible.


title:
Observational Constraints on Theories with a Blue Spectrum of Tensor
  Modes

abstract:
  Motivated by the string gas cosmological model, which predicts a blue tilt of
the primordial gravitational wave spectrum, we examine the constraints imposed
by current and planned observations on a blue tilted tensor spectrum. Starting
from an expression for the primordial gravitational wave spectrum normalized
using cosmic microwave background observations, pulsar timing, direct detection
and nucleosynthesis bounds are examined. If we assume a tensor to scalar ratio
on scales of the CMB which equals the current observational upper bound, we
obtain from these current observations constraints on the tensor spectral index
of $n_{T} \lesssim 0.79$, $n_{T} \lesssim 0.53$, and $n_{T} \lesssim 0.15$
respectively.


title: A Note on Quantum Hamming Bound

abstract:
  Proving the quantum Hamming bound for degenerate nonbinary stabilizer codes
has been an open problem for a decade. In this note, I prove this bound for
double error-correcting degenerate stabilizer codes. Also, I compute the
maximum length of single and double error-correcting MDS stabilizer codes over
finite fields.


title:
Optical emission line properties of Narrow Line Seyfert 1s and
  comparison AGN

abstract:
  Based on a new spectroscopic sample observed using the WHT, we examine the
kinematic properties of the various emission line regions in narrow line
Seyfert 1 galaxies (NLS1s) by modelling their profiles using multiple component
fits. We interpret these results by comparison with velocity components
observed for different lines species covered in the same spectrum, and
equivalent components measured in the spectra of some broad line Seyfert 1s and
a representative Seyfert 2 galaxy. We find that the fits to the Halpha and
Hbeta line profiles in NLS1s require an additional broad (~3000km/s) component
that might correspond to a suppressed broad line region with similar kinematics
to those of typical broad line Seyfert 1s. From the profiles of the forbidden
high ionisation lines (FHILs) in NLS1s, we find evidence that they appear to
trace an `intermediate' velocity region with kinematics between the standard
broad and narrow line regions. Weaker evidence of this region is also present
in the profiles of the permitted Balmer lines. Finally, we note that despite
having similar ionisation potentials, the relative intensities of the highly
ionised lines of [Fe X]6374 and [FeXI]7892 show considerable dispersion from
one galaxy to another. The interpretation of this requires further modelling,
but suggests the possibility of using the ratio as a diagnostic to constrain
the physical conditions of the FHIL emitting region and possibly the shape of
the spectral energy distribution in the vicinity of 200eV. This spectral region
is very difficult to observe directly due to photoelectric absorption both in
our Galaxy and intrinsic to the source.


title: The Properties of Dense Molecular Gas in the Milky Way and Galaxies

abstract:
  We review the evidence for a constant star formation rate per unit mass in
dense molecular gas in the Milky Way and the extragalactic correlations of L_IR
with L' from observations of dense molecular gas. We discuss the connection
between the constant SFR/M interpretation in dense gas and the global
Schmidt-Kennicutt star formation law.


title: Physics in Carnacki's investigations

abstract:
  In the stories of Carnacki, created by the English writer William H. Hodgson
and written between 1910 and 1912, we find an interesting mixture of science
and fantasy. In spite of the fact that Carnacki is a ghost finder, who
investigates in an environment where supernatural is acting, we see the
character using technology and sometimes discussing of physics phenomena such
as X-rays. The Carnacki's stories can be seen as mirrors of the physics and
technology knowledge at the beginning of Twentieth Century, in the society
outside scientific circles.


title: Nuclear deformation effect on the binding energies in heavy ions

abstract:
  Nuclear deformation effects on the binding energies in heavy ions are
investigated. Approximate formulas for the nuclear-size correction and the
isotope shift for deformed nuclei are derived. Combined with direct numerical
evaluations, these formulas are employed to reanalyse experimental data on the
nuclear-charge-distribution parameters in $^{238}\textrm{U}$ and to revise the
nuclear-size corrections to the binding energies in H- and Li-like
$^{238}\textrm{U}$. As a result, the theoretical uncertainties for the
ground-state Lamb shift in $^{238}\textrm{U}^{91+}$ and for the $2p_{1/2}-2s$
transition energy in $^{238}\textrm{U}^{89+}$ are significantly reduced. The
isotope shift of the $2p_{j}-2s$ transition energies for
$^{142}\textrm{Nd}^{57+}$ and $^{150}\textrm{Nd}^{57+}$ is also evaluated
including nuclear size and nuclear recoil effects within a full QED treatment.


title: Spin Transfer Torques

abstract:
  This tutorial article introduces the physics of spin transfer torques in
magnetic devices. We provide an elementary discussion of the mechanism of spin
transfer torque, and review the theoretical and experimental progress in this
field. Our intention is to be accessible to beginning graduate students. This
is the introductory paper for a cluster of "Current Perspectives" articles on
spin transfer torques published in volume 320 of the Journal of Magnetism and
Magnetic Materials. This article is meant to set the stage for the others which
follow it in this cluster; they focus in more depth on particularly interesting
aspects of spin-torque physics and highlight unanswered questions that might be
productive topics for future research.


title:
Induced antiferromagnetism and large magnetoresistances in
  RuSr2(Nd,Y,Ce)2Cu2O10-d ruthenocuprates

abstract:
  RuSr2(Nd,Y,Ce)2Cu2O10-d ruthenocuprates have been studied by neutron
diffraction, magnetotransport and magnetisation measurements and the electronic
phase diagram is reported. Separate Ru and Cu spin ordering transitions are
observed, with spontaneous Cu antiferromagnetic order for low hole doping
levels p, and a distinct, induced-antiferromagnetic Cu spin phase in the 0.02 <
p < 0.06 pseudogap region. This ordering gives rise to large negative
magnetoresistances which vary systematically with p in the
RuSr2Nd1.8-xY0.2CexCu2O10-d series. A collapse of the magnetoresistance (MR)
and magnetisation in the pre-superconducting region may signify the onset of
superconducting fluctuations.


title:
Potts models on hierarchical lattices and Renormalization Group dynamics
  II: examples and numerical results

abstract:
  We obtain the exact renormalization map and plots of Lee-Yang and Fisher
zeros distributions for Potts models on a number of hierarchical lattices: the
diamond hierarchical lattice, a lattice we call spider web, the Sierpinski
gasket and cylinders. Such models are only examples among the ones we can study
in the general framework of hierarchical lattices, developed in a previous
paper.


title:
Chemical Tuning of Positive and Negative Magnetoresistances, and
  Superconductivity in 1222-type Ruthenocuprates

abstract:
  High critical-temperature superconductivity and large (colossal)
magnetoresistances are two important electronic conducting phenomena found in
transition metal oxides. High-Tc materials have applications such as
superconducting magnets for MRI and NMR, and magnetoresistive materials may
find use in magnetic sensors and spintronic devices. Here we report chemical
doping studies of RuSr2(R2-xCex)Cu2O10-d ruthenocuprates which show that a
single oxide system can be tuned between superconductivity at high hole dopings
and varied magnetoresistive properties at low doping levels. A robust variation
of negative magnetoresistance with hole concentration is found in the
RuSr2R1.8-xY0.2CexCu2O10-d series, while RuSr2R1.1Ce0.9Cu2O10-d materials show
an unprecedented crossover from negative to positive magnetoresistance with
rare earth (R) ion radius.


title: Fractal Threshold Behavior in Vacuum Gravitational Collapse

abstract:
  We present the numerical evidence for fractal threshold behavior in the five
dimensional vacuum Einstein equations satisfying the cohomogeneity-two triaxial
Bianchi type-IX ansatz. In other words, we show that a flip of the wings of a
butterfly may influence the process of the black hole formation.


title: Spreadsheet Risk - A New Direction for HMRC?

abstract:
  Her Majestys Revenue & Customs (HMRC) was born out of the need to create a UK
tax authority by merging both the Inland Revenue and HM Customs & Excise into
one department. HMRC encounters spreadsheets in tax-payers systems on a very
regular basis as well as being a heavy user of spreadsheets internally. The
approach to spreadsheet risk assessment and spreadsheet audit is by the use of
trained computer auditors and data handlers. This, by definition, limits the
use of our specialist spreadsheet audit tool to such trained staff. In order to
tackle the growing use of spreadsheets, a new way of approaching the problem
has been piloted. The aim is to issue all staff who come across spreadsheets
with a simple to use analysis and risk assessment tool, based on the
departmental software SpACE (Spreadsheet Audit & Compliance Examination).


title:
Rotating Spacetimes with Asymptotic Non-Flat Structure and the
  Gyromagnetic Ratio

abstract:
  In general relativity, the gyromagnetic ratio for all stationary,
axisymmetric and asymptotically flat Einstein-Maxwell fields is known to be
g=2. In this paper, we continue our previous works of examination this result
for rotating charged spacetimes with asymptotic non-flat structure. We first
consider two instructive examples of these spacetimes: The spacetime of a
Kerr-Newman black hole with a straight cosmic string on its axis of symmetry
and the Kerr-Newman Taub-NUT spacetime. We show that for both spacetimes the
gyromagnetic ratio g=2 independent of their asymptotic structure. We also
extend this result to a general class of metrics which admit separation of
variables for the Hamilton-Jacobi and wave equations. We proceed with the study
of the gyromagnetic ratio in higher dimensions by considering the general
solution for rotating charged black holes in minimal five-dimensional gauged
supergravity. We obtain the analytic expressions for two distinct gyromagnetic
ratios of these black holes that are associated with their two independent
rotation parameters. These expressions reveal the dependence of the
gyromagnetic ratio on both the curvature radius of the AdS background and the
parameters of the black holes: The mass, electric charge and two rotation
parameters. We explore some special cases of interest and show that when the
two rotation parameters are equal to each other and the rotation occurs at the
maximum angular velocity, the gyromagnetic ratio g=4 regardless of the value of
the electric charge. This agrees precisely with our earlier result obtained for
general Kerr-AdS black holes with a test electric charge. We also show that in
the BPS limit the gyromagnetic ratio for a supersymmetric black hole with equal
rotation parameters ranges between 2 and 4.


title: Equation of State and Phases of Polarized Unitary Fermi Gas

abstract:
  The equation of state of the partially polarized two component Fermi gas at
zero temperature in the unitary limit is computed by {\it ab initio} auxiliary
field Monte Carlo method. We obtain the critical ratio of the chemical
potentials $\mu_\downarrow/\mu_\uparrow$ at the phase transitions. The value of
$\mu_\downarrow/\mu_\uparrow$ at the transition between the fully paired
superfluid and the partially polarized phase is 0.11 while the critical value
for the phase transition between the partially polarized phase and the fully
polarized normal fluid is -0.59. We also determine the radial boundaries of the
phase transitions of the Fermi gas in the harmonic trap as function of the
total polarization. We find that beyond the critical polarization 0.65, the
fully paired superfluid core disappears in the trapped Fermi gas.


title:
The c2d Spitzer spectroscopic survey of ices around low-mass young
  stellar objects II: CO2

abstract:
  This paper presents Spitzer-IRS spectroscopy of the CO2 15.2 micron bending
mode toward a sample of 50 embedded low-mass stars in nearby star-forming
clouds, taken mostly from the ``Cores to Disks (c2d)'' Legacy program. The
average abundance of solid CO2 relative to water in low-mass protostellar
envelopes is 0.32 +/- 0.02, significantly higher than that found in quiescent
molecular clouds and in massive star forming regions. It is found that a
decomposition of all the observed CO2 bending mode profiles requires a minimum
of five unique components. Roughly 2/3 of the CO2 ice is found in a water-rich
environment, while most of the remaining 1/3 is found in a CO environment.
Ground-based observations of solid CO toward a large subset of the c2d sample
are used to further constrain the CO2:CO component and suggest a model in which
low-density clouds form the CO2:H2O component and higher density clouds form
the CO2:CO ice during and after the freeze-out of gas-phase CO. It is suggested
that the subsequent evolution of the CO2 and CO profiles toward low-mass
protostars, in particular the appearance of the splitting of the CO2 bending
mode due to pure, crystalline CO2, is first caused by distillation of the
CO2:CO component through evaporation of CO due to thermal processing to ~20-30
K in the inner regions of infalling envelopes. The formation of pure CO2 via
segregation from the H2O rich mantle may contribute to the band splitting at
higher levels of thermal processing (>50 K), but is harder to reconcile with
the physical structure of protostellar envelopes around low-luminosity objects.


title: Cosmological birefringence induced by neutrino current

abstract:
  We review our recent work on the cosmological birefringence. We propose a new
type of effective interactions in terms of the $CPT$-even dimension-six
Chern-Simons-like term to generate the cosmological birefringence. We use the
neutrino number asymmetry to induce a non-zero rotation polarization angle in
the data of the cosmic microwave background radiation polarization.


title: The electromagnetic effects in $K_{e4}$ decay

abstract:
  The final state interaction of pions in $K_{e4}$ decay allows one to obtain
the value of the isospin and angular momentum zero $\pi\pi$ scattering length
$a_0^0$.We take into account the electromagnetic interaction of pions and
isospin symmetry breaking effects caused by different masses of neutral and
charged pions and estimate the impact of these effects on the procedure of
scattering length extraction from $K_{e4}$ decay.


title:
Integral equations and large-time asymptotics for finite-temperature
  Ising chain correlation functions

abstract:
  This work concerns the dynamical two-point spin correlation functions of the
transverse Ising quantum chain at finite (non-zero) temperature, in the
universal region near the quantum critical point. They are correlation
functions of twist fields in the massive Majorana fermion quantum field theory.
At finite temperature, these are known to satisfy a set of integrable partial
differential equations, including the sinh-Gordon equation. We apply the
classical inverse scattering method to study them, finding that the ``initial
scattering data'' corresponding to the correlation functions are simply related
to the one-particle finite-temperature form factors calculated recently by one
of the authors. The set of linear integral equations (Gelfand-Levitan-Marchenko
equations) associated to the inverse scattering problem then gives, in
principle, the two-point functions at all space and time separations, and all
temperatures. From them, we evaluate the large-time asymptotic expansion ``near
the light cone'', in the region where the difference between the space and time
separations is of the order of the correlation length.

categories: math-ph cond-mat.stat-mech hep-th math.MP


title: Critical phenomena in gravitational collapse

abstract:
  As first discovered by Choptuik, the black hole threshold in the space of
initial data for general relativity shows both surprising structure and
surprising simplicity. Universality, power-law scaling of the black hole mass,
and scale echoing have given rise to the term "critical phenomena". They are
explained by the existence of exact solutions which are attractors within the
black hole threshold, that is, attractors of codimension one in phase space,
and which are typically self-similar. Critical phenomena give a natural route
from smooth initial data to arbitrarily large curvatures visible from infinity,
and are therefore likely to be relevant for cosmic censorship, quantum gravity,
astrophysics, and our general understanding of the dynamics of general
relativity.


title:
Extracting the Gamma Ray Signal from Dark Matter Annihilation in the
  Galactic Center Region

abstract:
  The GLAST satellite mission will study the gamma ray sky with considerably
greater exposure than its predecessor EGRET. In addition, it will be capable of
measuring the arrival directions of gamma rays with much greater precision.
These features each significantly enhance GLAST's potential for identifying
gamma rays produced in the annihilations of dark matter particles. The combined
use of spectral and angular information, however, is essential if the full
sensitivity of GLAST to dark matter is to be exploited. In this paper, we
discuss the separation of dark matter annihilation products from astrophysical
backgrounds, focusing on the Galactic Center region, and perform a forecast for
such an analysis. We consider both point-like and diffuse astrophysical
backgrounds and model them using a point-spread-function for GLAST. While the
results of our study depend on the specific characteristics of the dark matter
signal and astrophysical backgrounds, we find that in many scenarios it is
possible to successfully identify dark matter annihilation radiation, even in
the presence of significant astrophysical backgrounds.


title: Occurrence of Metal-free Galaxies in the Early Universe

abstract:
  The character of the first galaxies at redshifts z > 10 strongly depends on
their level of pre-enrichment, which is in turn determined by the rate of
primordial star formation prior to their assembly. In order for the first
galaxies to remain metal-free, star formation in minihaloes must be highly
suppressed, most likely by H2-dissociating Lyman-Werner (LW) radiation. We show
that the build-up of such a strong LW background is hindered by two effects.
Firstly, the level of the LW background is self-regulated, being produced by
the Population III (Pop III) star formation which it, in turn, suppresses.
Secondly, the high opacity to LW photons which is built up in the relic H II
regions left by the first stars acts to diminish the global LW background.
Accounting for a self-regulated LW background, we estimate a lower limit for
the rate of Pop III star formation in minihaloes at z > 15. Further, we
simulate the formation of a 'first galaxy' with virial temperature T > 10^4 K
and total mass > 10^8 M_Sun at z > 10, and find that complete suppression of
previous Pop III star formation is unlikely, with stars of > 100 M_Sun (Pop
III.1) and > 10 M_Sun (Pop III.2) likely forming. Finally, we discuss the
implications of these results for the nature of the first galaxies, which may
be observed by future missions such as the James Webb Space Telescope.


title:
Complete Set of Commuting Symmetry Operators for the Klein-Gordon
  Equation in Generalized Higher-Dimensional Kerr-NUT-(A)dS Spacetimes

abstract:
  We consider the Klein-Gordon equation in generalized higher-dimensional
Kerr-NUT-(A)dS spacetime without imposing any restrictions on the functional
parameters characterizing the metric. We establish commutativity of the
second-order operators constructed from the Killing tensors found in
arXiv:hep-th/0612029 and show that these operators, along with the first-order
operators originating from the Killing vectors, form a complete set of
commuting symmetry operators (i.e., integrals of motion) for the Klein-Gordon
equation. Moreover, we demonstrate that the separated solutions of the
Klein-Gordon equation obtained in arXiv:hep-th/0611245 are joint eigenfunctions
for all of these operators. We also present explicit form of the zero mode for
the Klein-Gordon equation with zero mass.
  In the semiclassical approximation we find that the separated solutions of
the Hamilton-Jacobi equation for geodesic motion are also solutions for a set
of Hamilton-Jacobi-type equations which correspond to the quadratic conserved
quantities arising from the above Killing tensors.


title:
W-algebra W(2,2) and the vertex operator algebra L(1/2,0)\otimes
  L(1/2,0)

abstract:
  In this paper the W-algebra W(2,2) and its representation theory are studied.
It is proved that a simple vertex operator algebra generated by two weight 2
vectors is either a vertex operator algebra associated to a highest irreducible
W(2,2)-module or a tensor product of two irreducible Virasoro vertex operator
algebras. Furthermore, any rational, C_2-cofinite simple vertex operator
algebra whose weight 1 subspace is zero and weight 2 subspace is 2-dimensional,
and with central charge c=1 is isomorphic to L(1/2,0)\otimes L(1/2,0).


title:
Toward classfication of rational vertex operator algebras with central
  charges less than 1

abstract:
  The rational and C_2-cofinite simple vertex operator algebras whose effective
central charges and the central charges c are equal and less than 1 are
classified. Such a vertex operator algebra is zero if c<0 and C if c=0. If c>0,
it is an extension of discrete Virasoro vertex operator algebra L(c_{p,q},0) by
its irreducible modules. It is also proved that for any rational and
C_2-cofinite simple vertex operator algebra whose effective central charge and
central charge are equal, the vertex operator subalgebra generated by the
Virasoro vector is simple.


title: Constraints on jet-driven disk accretion in Sagittarius A*

abstract:
  We revisit theoretical and observational constraints on geometrically-thin
disk accretion in Sagittarius A* (Sgr A*). We show that the combined effects of
mass outflows and electron energization in the hot part of the accretion flow
can deflate the inflowing gas from a geometrically-thick structure. This allows
the gas to cool and even thermalize on an inflow timescale. As a result, a
compact, relatively cool disk may form at small radii. We show that magnetic
coupling between the relativistic disk and a steady-state jet results in a disk
that is less luminous than a standard relativistic disk accreting at the same
rate. This relaxes the observational constraints on thin-disk accretion in Sgr
A* (and by implication, other Low-Luminosity Active Galactic Nulcei, LLAGN). We
find typical cold gas accretion rates of a few * 10^{-9} solar masses / yr. We
also find that the predicted modified disk emission is compatible with existing
near-infrared (NIR) observations of Sgr A* in its quiescent state provided that
the disk inclination angle is > 87 degrees and that the jet extracts more than
75% of the accretion power.


title: On Commutativity and Finiteness in Groups

abstract:
  The second author introduced notions of weak permutability and commutativity
between groups and proved the finiteness of a group generated by two weakly
permutable finite groups. Two groups H,K weakly commute provided there exists a
bijection f: H -> K which fixes the identity element and such that h commutes
with its image h^f for all h in H. The present paper gives support to
conjectures about the nilpotency of groups generated by two weakly commuting
finite abelian groups H,K.


title: An Attempt to Remove Quadratic Divergences in the Standard Theory

abstract:
  The quadratic divergences caused by Yukawa interactions in the standard
theory of elementary particle physics is shown to be removed by introducing
finite-mass complex-ghost regulator fields. In this modification of the
standard theory, its manifest covariance, renormalizability, gauge invariance
and unitarity are retained, and no new observable particles are introduced.


title: Effective Interactions in Soft Materials

abstract:
  Soft materials, such as colloidal suspensions, polymer solutions, and
biological systems, are typically multicomponent mixtures of macromolecules and
simpler components (e.g., microions, monomers, solvent) that can assemble into
complex structures spanning broad length and time scales. Many characteristic
traits of soft matter, e.g., mechanical fragility, sensitivity to external
influence, and tunable thermal and optical properties, emerge from a mingling
of microscopic and mesoscopic constituents. Large asymmetries in size and
charge between macromolecules and microscopic components often make impractical
the explicit modeling of all degrees of freedom over physically significant
length and time scales. The complexity often can be reduced, however, by
pre-averaging (coarse-graining) the degrees of freedom of some microscopic
components, thus mapping the real system onto a simpler model of fewer
components, but governed by effective interparticle interactions. This chapter
reviews the statistical mechanical foundations of effective interactions in
soft materials and discusses illustrative applications to charged colloids,
polyelectrolytes, and colloid-polymer mixtures


title: The No-Boundary Measure of the Universe

abstract:
  We consider the no-boundary proposal for homogeneous isotropic closed
universes with a cosmological constant and a scalar field with a quadratic
potential. In the semi-classical limit, it predicts classical behavior at late
times if the initial scalar field is more than a certain minimum. If the
classical late time histories are extended back, they may be singular or bounce
at a finite radius. The no-boundary proposal provides a probability measure on
the classical solutions which selects inflationary histories but is heavily
biased towards small amounts of inflation. This would not be compatible with
observations. However we argue that the probability for a homogeneous universe
should be multiplied by exp(3N) where N is the number of e-foldings of slow
roll inflation to obtain the probability for what we observe in our past light
cone. This volume weighting is similar to that in eternal inflation. In a
landscape potential, it would predict that the universe would have a large
amount of inflation and that it would start in an approximately de Sitter state
near a saddle-point of the potential. The universe would then have always been
in the semi-classical regime.


title:
On Secure Quantum Key Distribution Using Continuous Variables of Single
  Photons

abstract:
  We analyse the distribution of secure keys using quantum cryptography based
on the continuous variable degree of freedom of entangled photon pairs. We
derive the information capacity of a scheme based on the spatial entanglement
of photons from a realistic source, and show that the standard measures of
security known for quadrature-based continuous variable quantum cryptography
(CV-QKD) are inadequate. A specific simple eavesdropping attack is analysed to
illuminate how secret information may be distilled well beyond the bounds of
the usual CV-QKD measures.


title: Collisional properties of weakly bound heteronuclear dimers

abstract:
  We consider collisional properties of weakly bound heteronuclear molecules
(dimers) formed in a two-species mixture of atoms with a large mass difference.
We focus on dimers containing light fermionic atoms as they manifest
collisional stability due to an effective dimer-dimer repulsion originating
from the exchange of the light atoms. In order to solve the dimer-dimer
scattering problem we develop a theoretical approach, which provides a
physically transparent and quantitative description of this four-atom system in
terms of three- and two-body observables. We calculate the elastic scattering
amplitude and the rates of inelastic processes such as the trimer formation and
the relaxation of dimers into deeply bound molecular states. Irrespective of
whether the heavy atoms are bosons or fermions, the inelastic rate can be
significantly lower than the rate of elastic collisions. Moreover, the
measurement of the inelastic rate which is a four-body observable, can be an
efficient and precise tool for determining three-body observables such as the
three-body parameter, positions of Efimov states and their lifetimes.


title:
Dynamics of periodic anticrossings: Decoherence, pointer states and
  hysteresis curves

abstract:
  We consider a strongly driven two-level (spin) system, with a periodic
external field that induces a sequence of avoided level crossings. The spin
system interacts with a bosonic reservoir which leads to decoherence. A
Markovian dynamical equation is introduced without relying on the rotating wave
approximation in the system-external field interaction. We show that the time
evolution of the two-level system is directed towards an incoherent sum of
periodic Floquet states regardless of the initial state and even the type of
the coupling to the environment. Analyzing the time scale of approaching these
time-dependent pointer states, information can be deduced concerning the nature
and strength of the system-environment coupling. The inversion as a function of
the external field is usually multi-valued, and the form of these hysteresis
curves is qualitatively different for low and high temperatures. For moderate
temperatures we found that the series of Landau-Zener-St\"{u}ckelberg-type
transitions still can be used for state preparation, regardless of the
decoherence rate. Possible applications include quantum information processing
and molecular nanomagnets.


title: Strategies for Addressing Spreadsheet Compliance Challenges

abstract:
  Most organizations today use spreadsheets in some form or another to support
critical business processes. However the financial resources, and developmental
rigor dedicated to them are often minor in comparison to other enterprise
technology. The increasing focus on achieving regulatory and other forms of
compliance over key technology assets has made it clear that organizations must
regard spreadsheets as an enterprise resource and account for them when
developing an overall compliance strategy. This paper provides the reader with
a set of practical strategies for addressing spreadsheet compliance from an
organizational perspective. It then presents capabilities offered in the 2007
Microsoft Office System which can be used to help customers address compliance
challenges.


title:
Superfluid and Mott Insulator phases of one-dimensional Bose-Fermi
  mixtures

abstract:
  We study the ground state phases of Bose-Fermi mixtures in one-dimensional
optical lattices with quantum Monte Carlo simulations using the Canonical Worm
algorithm. Depending on the filling of bosons and fermions, and the on-site
intra- and inter-species interaction, different kinds of incompressible and
superfluid phases appear. On the compressible side, correlations between bosons
and fermions can lead to a distinctive behavior of the bosonic superfluid
density and the fermionic stiffness, as well as of the equal-time Green
functions, which allow one to identify regions where the two species exhibit
anticorrelated flow. We present here complete phase diagrams for these systems
at different fillings and as a function of the interaction parameters.


title: Testing Atom and Neutron Neutrality with Atom Interferometry

abstract:
  We propose an atom-interferometry experiment based on the scalar
Aharonov-Bohm effect which detects an atom charge at the 10^{-28}e level, and
improves the current laboratory limits by 8 orders of magnitude. This setup
independently probes neutron charges down to 10^{-28}e, 7 orders of magnitude
below current bounds.


title: A nonperturbative parametrization and scenario for EFT renormalization

abstract:
  We present a universal form of the $T$-matrices renormalized in
nonperturbative regime and the ensuing notions and properties that fail
conventional wisdoms. A universal scale is identified and shown to be
renormalization group invariant. The effective range parameters are derived in
a nonperturbative scenario with some new predictions within the realm of
contact potentials. Some controversies are shown to be due to the failure of
conventional wisdoms.


title:
Trapping of Neutral Mercury Atoms and Prospects for Optical Lattice
  Clocks

abstract:
  We report a vapor-cell magneto-optical trapping of Hg isotopes on the
${}^1S_0-{}^3P_1$ intercombination transition. Six abundant isotopes, including
four bosons and two fermions, were trapped. Hg is the heaviest non-radioactive
atom trapped so far, which enables sensitive atomic searches for ``new
physics'' beyond the standard model. We propose an accurate optical lattice
clock based on Hg and evaluate its systematic accuracy to be better than
$10^{-18}$. Highly accurate and stable Hg-based clocks will provide a new
avenue for the research of optical lattice clocks and the time variation of the
fine-structure constant.


title:
On Properties of the Ising Model for Complex Energy/Temperature and
  Magnetic Field

abstract:
  We study some properties of the Ising model in the plane of the complex
(energy/temperature)-dependent variable $u=e^{-4K}$, where $K=J/(k_BT)$, for
nonzero external magnetic field, $H$. Exact results are given for the phase
diagram in the $u$ plane for the model in one dimension and on infinite-length
quasi-one-dimensional strips. In the case of real $h=H/(k_BT)$, these results
provide new insights into features of our earlier study of this case. We also
consider complex $h=H/(k_BT)$ and $\mu=e^{-2h}$. Calculations of complex-$u$
zeros of the partition function on sections of the square lattice are
presented. For the case of imaginary $h$, i.e., $\mu=e^{i\theta}$, we use exact
results for the quasi-1D strips together with these partition function zeros
for the model in 2D to infer some properties of the resultant phase diagram in
the $u$ plane. We find that in this case, the phase boundary ${\cal B}_u$
contains a real line segment extending through part of the physical
ferromagnetic interval $0 \le u \le 1$, with a right-hand endpoint $u_{rhe}$ at
the temperature for which the Yang-Lee edge singularity occurs at $\mu=e^{\pm
i\theta}$. Conformal field theory arguments are used to relate the
singularities at $u_{rhe}$ and the Yang-Lee edge.


title:
Resistively Detected NMR in Quantum Hall States: Investigation of the
  anomalous lineshape near $\nu=1$

abstract:
  A study of the resistively detected nuclear magnetic resonance (RDNMR)
lineshape in the vicinity of $\nu=1$ was performed on a high-mobility 2D
electron gas formed in GaAs/AlGaAs. In higher Landau levels, application of an
RF field at the nuclear magnetic resonance frequency coincides with an observed
minimum in the longitudinal resistance, as predicted by the simple hyperfine
interaction picture. Near $\nu=1$ however, an anomalous dispersive lineshape is
observed where a resistance peak follows the usual minimum. In an effort to
understand the origin of this anomalous peak we have studied the resonance
under various RF and sample conditions. Interestingly, we show that the
lineshape can be completely inverted by simply applying a DC current. We
interpret this as evidence that the minima and maxima in the lineshape
originate from two distinct mechanisms.


title: Relational evolution of a simple quantum Hamiltonian model

abstract:
  We study the quantum dynamics of a time reparametrization invariant system
with a vanishing Hamiltonian. The evolution of the physical degrees of freedom
of the system is described, both at the classical and at the quantum level, in
relational terms by the construction of an internal time parameter. We use the
Pegg-Barnett phase operator formalism in finite dimensional Hilbert space as an
essential ingredient.


title: One, Two, and $n$ Qubit Decoherence

abstract:
  We study decoherence of one, two, and $n$ non-interacting qubits.
Decoherence, measured in terms of purity, is calculated in linear response
approximation, making use of the spectator configuration. The environment and
its interaction with the qubits are modelled by random matrices. For two
qubits, numerical studies reveal a simple one to one correspondence between its
decoherence and its internal entanglement decay. Using this relation we are
able to give a formula for concurrence decay. For large environments the
evolution induces a unital channel in the two qubits, providing a partial
explanation for the relation above. Using a kicked Ising spin network, we study
the exact evolution of two non-interacting qubits in the presence of a spin
bath. We find that the entanglement (as measured by concurrence) of the two
qubits has a close relation to the purity of the pair, and closely follows an
analytic relation derived for Werner states. As a collateral result we find
that an integrable environment causes quadratic decay of concurrence as well as
of purity, while a chaotic environment causes linear decay. Both quantities
display recurrences in some integrable environments. Good agreement with the
results found using random matrix theory is obtained. Finally, we analyze
decoherence of a quantum register in the absence of non-local operations. The
problem is solved in terms of a sum rule which implies linear scaling in the
number of qubits. Each term involves a single qubit and its entanglement with
the remaining ones. Two conditions are essential: decoherence must be small and
the coupling of different qubits must be uncorrelated in the interaction
picture. We apply the result to the random matrix model, and illustrate its
reach considering a GHZ state coupled to a spin bath.


title: The Friedberg-Lee model at finite temperature and density

abstract:
  The Friedberg-Lee model is studied at finite temperature and density. By
using the finite temperature field theory, the effective potential of the
Friedberg-Lee model and the bag constant $B(T)$ and $B(T,\mu)$ have been
calculated at different temperatures and densities. It is shown that there is a
critical temperature $T_{C}\simeq 106.6 \mathrm{MeV}$ when $\mu=0 \mathrm{MeV}$
and a critical chemical potential $\mu \simeq 223.1 \mathrm{MeV}$ for fixing
the temperature at $T=50 \mathrm{MeV}$. We also calculate the soliton solutions
of the Friedberg-Lee model at finite temperature and density. It turns out that
when $T\leq T_{C}$ (or $\mu \leq \mu_C$), there is a bag constant $B(T)$ (or
$B(T,\mu)$) and the soliton solutions are stable. However, when $T>T_{C}$ (or
$\mu>\mu_C$) the bag constant $B(T)=0 \mathrm{MeV}$ (or $B(T,\mu)=0
\mathrm{MeV}$) and there is no soliton solution anymore, therefore, the
confinement of quarks disappears quickly.


title: Verifying black hole orbits with gravitational spectroscopy

abstract:
  Gravitational waves from test masses bound to geodesic orbits of rotating
black holes are simulated, using Teukolsky's black hole perturbation formalism,
for about ten thousand generic orbital configurations. Each binary radiates
power exclusively in modes with frequencies that are
integer-linear-combinations of the orbit's three fundamental frequencies. The
following general spectral properties are found with a survey of orbits: (i)
99% of the radiated power is typically carried by a few hundred modes, and at
most by about a thousand modes, (ii) the dominant frequencies can be grouped
into a small number of families defined by fixing two of the three integer
frequency multipliers, and (iii) the specifics of these trends can be
qualitatively inferred from the geometry of the orbit under consideration.
Detections using triperiodic analytic templates modeled on these general
properties would constitute a verification of radiation from an adiabatic
sequence of black hole orbits and would recover the evolution of the
fundamental orbital frequencies. In an analogy with ordinary spectroscopy, this
would compare to observing the Bohr model's atomic hydrogen spectrum without
being able to rule out alternative atomic theories or nuclei. The suitability
of such a detection technique is demonstrated using snapshots computed at
12-hour intervals throughout the last three years before merger of a kludged
inspiral. Because of circularization, the number of excited modes decreases as
the binary evolves. A hypothetical detection algorithm that tracks mode
families dominating the first 12 hours of the inspiral would capture 98% of the
total power over the remaining three years.


title: Charmed baryon strong decays in a chiral quark model

abstract:
  Charmed baryon strong decays are studied in a chiral quark model. The data
for the decays of $\Lambda^+_c(2593)$, $\Lambda^+_c(2625)$, $\Sigma^{++,+,0}_c$
and $\Sigma^{+,0}_c(2520)$, are accounted for successfully, which allows to fix
the pseudoscalar-meson-quark couplings in an effective chiral Lagrangian.
Extending this framework to analyze the strong decays of the newly observed
charmed baryons, we classify that both $\Lambda_c(2880)$ and $\Lambda_c(2940)$
are $D$-wave states in the N=2 shell; $\Lambda_c(2880)$ could be $|\Lambda_c ^2
D_{\lambda\lambda}{3/2}^+>$ and $\Lambda_c(2940)$ could be $|\Lambda_c ^2
D_{\lambda\lambda}{5/2}^+>$. Our calculation also suggests that
$\Lambda_c(2765)$ is very likely a $\rho$-mode $P$-wave excited state in the
N=1 shell, and favors a $|\Lambda_c ^4P_\rho 1/2^->$ configuration. The
$\Sigma_c(2800)$ favors being a $|\Sigma_c ^2P_\lambda{1/2}^->$ state. But its
being $|\Sigma^{++}_c ^4 P_\lambda{5/2}^->$ cannot be ruled out.


title:
Dark-matter sterile neutrinos in models with a gauge singlet in the
  Higgs sector

abstract:
  Sterile neutrino with mass of several keV can be the cosmological dark
matter, can explain the observed velocities of pulsars, and can play an
important role in the formation of the first stars. We describe the production
of sterile neutrinos in a model with an extended Higgs sector, in which the
Majorana mass term is generated by the vacuum expectation value of a
gauge-singlet Higgs boson. In this model the relic abundance of sterile
neutrinos does not necessarily depend on their mixing angles, the
free-streaming length can be much smaller than in the case of warm dark matter
produced by neutrino oscillations, and, therefore, some of the previously
quoted bounds do not apply. The presence of the gauge singlet in the Higgs
sector has important implications for the electroweak phase transition,
baryogenesis, and the upcoming experiments at the Large Hadron Collider and a
Linear Collider.


title:
Super-rigidity for CR embeddings of real hypersurfaces into
  hyperquadrics

abstract:
  Let $Q^N_l\subset \bC\bP^{N+1}$ denote the standard real, nondegenerate
hyperquadric of signature $l$ and $M\subset \bC^{n+1}$ a real, Levi
nondegenerate hypersurface of the same signature $l$. We shall assume that
there is a holomorphic mapping $H_0\colon U\to \bC\bP^{N_0+1}$, where $U$ is
some neighborhood of $M$ in $\bC^{n+1}$, such that $H_0(M)\subset Q^{N_0}_l$
but $H(U)\not\subset Q^{N_0}_l$. We show that if $N_0-n<l$ then, for any $N\geq
N_0$, any holomorphic mapping $H\colon U\to \bC\bP^{N+1}$ with $H(M)\subset
Q^{N}_l$ and $H(U)\not\subset Q^{N_0}_l$ must be the standard linear embedding
of $Q^{N_0}_l$ into $Q^N_l$ up to conjugation by automorphisms of $Q^{N_0}_l$
and $Q^N_l$.


title: A Remark on a Theorem by Kodama and Shimizu

abstract:
  We prove a characterization theorem for the unit polydisc
$\Delta^n\subset\CC^n$ in the spirit of a recent result due to Kodama and
Shimizu. We show that if $M$ is a connected $n$-dimensional complex manifold
such that (i) the group $\hbox{Aut}(M)$ of holomorphic automorphisms of $M$
acts on $M$ with compact isotropy subgroups, and (ii) $\hbox{Aut}(M)$ and
$\hbox{Aut}(\Delta^n)$ are isomorphic as topological groups equipped with the
compact-open topology, then $M$ is holomorphically equivalent to $\Delta^n$.


title: Hierarchical pinning models, quadratic maps and quenched disorder

abstract:
  We consider a hierarchical model of polymer pinning in presence of quenched
disorder, introduced by B. Derrida, V. Hakim and J. Vannimenius in 1992, which
can be re-interpreted as an infinite dimensional dynamical system with random
initial condition (the disorder). It is defined through a recurrence relation
for the law of a random variable {R_n}_{n=1,2,...}, which in absence of
disorder (i.e., when the initial condition is degenerate) reduces to a
particular case of the well-known Logistic Map. The large-n limit of the
sequence of random variables 2^{-n} log R_n, a non-random quantity which is
naturally interpreted as a free energy, plays a central role in our analysis.
The model depends on a parameter alpha>0, related to the geometry of the
hierarchical lattice, and has a phase transition in the sense that the free
energy is positive if the expectation of R_0 is larger than a certain threshold
value, and it is zero otherwise. It was conjectured by Derrida et al. (1992)
that disorder is relevant (respectively, irrelevant or marginally relevant) if
1/2<alpha<1 (respectively, alpha<1/2 or alpha=1/2), in the sense that an
arbitrarily small amount of randomness in the initial condition modifies the
critical point with respect to that of the pure (i.e., non-disordered) model if
alpha is larger or equal to 1/2, but not if alpha is smaller than 1/2. Our main
result is a proof of these conjectures for the case alpha different from 1/2.
We emphasize that for alpha>1/2 we find the correct scaling form (for weak
disorder) of the critical point shift.


title: A Classification of Hidden-Variable Properties

abstract:
  Hidden variables are extra components added to try to banish counterintuitive
features of quantum mechanics. We start with a quantum-mechanical model and
describe various properties that can be asked of a hidden-variable model. We
present six such properties and a Venn diagram of how they are related. With
two existence theorems and three no-go theorems (EPR, Bell, and
Kochen-Specker), we show which properties of empirically equivalent
hidden-variable models are possible and which are not. Formally, our treatment
relies only on classical probability models, and physical phenomena are used
only to motivate which models to choose.


title:
Singularities in fidelity surfaces for quantum phase transitions: a
  geometric perspective

abstract:
  The fidelity per site between two ground states of a quantum lattice system
corresponding to different values of the control parameter defines a surface
embedded in a Euclidean space. The Gaussian curvature naturally quantifies
quantum fluctuations that destroy orders at transition points. It turns out
that quantum fluctuations wildly distort the fidelity surface near the
transition points, at which the Gaussian curvature is singular in the
thermodynamic limit. As a concrete example, the one-dimensional quantum Ising
model in a transverse field is analyzed. We also perform a finite size scaling
analysis for the transverse Ising model of finite sizes. The scaling behavior
for the Gaussian curvature is numerically checked and the correlation length
critical exponent is extracted, which is consistent with the conformal
invariance at the critical point.


title:
Ramifications of the Nuclear Symmetry Energy for Neutron Stars, Nuclei,
  and Heavy-Ion Collisions

abstract:
  The pervasive role of the nuclear symmetry energy in establishing some
nuclear static and dynamical properties, and in governing some attributes of
neutron star properties is highlighted.


title: Phase reduction of stochastic limit cycle oscillators

abstract:
  We point out that the phase reduction of stochastic limit cycle oscillators
has been done incorrectly in the literature. We present a correct phase
reduction method for oscillators driven by weak external white Gaussian noises.
Numerical evidence demonstrates that the present phase equation properly
approximates the dynamics of the original full oscillator system.


title:
Comment on "Onset of Boson Mode at the Superconducting Critical Point of
  Underdoped YBa2Cu3Oy"

abstract:
  In a recent Letter [Phys. Rev. Lett. 97, 207001 (2006)], Doiron-Leyraud et
al. reported a study of low-temperature thermal conductivity of underdoped
YBa2Cu3Oy across the superconductor-insulator boundary and argued for a novel
bosonic mode as well as charge-neutral fermions. In this Comment, we show that
both of these claims are dubious.


title:
GRAvitational COSmology (GRACOS) code release announcement, for version
  1.0.1a9

abstract:
  This is to announce a recent release of version 1.0.1a9 of parallel load
balanced adaptive P3M cosmological N-body code named GRACOS. The code has been
under development over years and is available for the download at
http://www.gracos.org. GRACOS features: embedded script environment,
cosmological initial conditions generator including non-gaussian initial
conditions, particle data imager, mass density power spectrum estimator,
particle position and velocity integrator with a choice between KDK and DKD
integration schemes with Plummer force softening, file input and output with
four supported serial and one dynamic distributed data format, standard
installation procedure, and version specific documentation. GRACOS is released
under the GNU General Public License (GPL). High efficiency is achieved with a
number of implemented techniques such as timer-based load balancing using
Hilbert space filling curve, adaptive P3M method for short range force
computation, run-level compression in interprocessor communication, dynamic
allocation for irregular domains and various sorting algorithms.


title:
A condition number analysis of an algorithm for solving a system of
  polynomial equations with one degree of freedom

abstract:
  This article considers the problem of solving a system of $n$ real polynomial
equations in $n+1$ variables. We propose an algorithm based on Newton's method
and subdivision for this problem. Our algorithm is intended only for
nondegenerate cases, in which case the solution is a 1-dimensional curve. Our
first main contribution is a definition of a condition number measuring
reciprocal distance to degeneracy that can distinguish poor and well
conditioned instances of this problem. (Degenerate problems would be infinitely
ill conditioned in our framework.) Our second contribution, which is the main
novelty of our algorithm, is an analysis showing that its running time is
bounded in terms of the condition number of the problem instance as well as $n$
and the polynomial degrees.


title: Icons

abstract:
  Categorical orthodoxy has it that collections of ordinary mathematical
structures such as groups, rings, or spaces, form categories (such as the
category of groups); collections of 1-dimensional categorical structures, such
as categories, monoidal categories, or categories with finite limits, form
2-categories; and collections of 2-dimensional categorical structures, such as
2-categories or bicategories, form 3-categories.
  We describe a useful way in which to regard bicategories as objects of a
2-category. This is a bit surprising both for technical and for conceptual
reasons. The 2-cells of this 2-category are the crucial new ingredient; they
are the icons of the title. These can be thought of as ``the oplax natural
transformations whose components are identities'', but we shall also give a
more elementary description.
  We describe some properties of these icons, and give applications to monoidal
categories, to 2-nerves of bicategories, to 2-dimensional Lawvere theories, and
to bundles of bicategories.


title:
Systematic changes of the electronic structure of the diluted
  ferromagnetic oxide Li-doped Ni$_{1-x}$Fe$_x$O with hole doping

abstract:
  The electronic structure of Li-doped Ni$_{1-x}$Fe$_x$O has been investigated
using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS).
The Ni $2p$ core-level PES and XAS spectra were not changed by Li doping. In
contrast, the Fe$^{3+}$ intensity increased with Li doping relative to the
Fe$^{2+}$ intensity. However, the increase of Fe$^{3+}$ is only $\sim 5%$ of
the doped Li content, suggesting that most of the doped holes enter the O $2p$
and/or the charge-transferred configuration Ni $3d^8\underline{L}$. The Fe 3d
partial density of states and the host valence-band emission near valence-band
maximum increased with Li content, consistent with the increase of electrical
conductivity. Based on these findings, percolation of bound magnetic polarons
is proposed as an origin of the ferromagnetic behavior.


title: Underlying Determinism, Stationary Phase and Quantum Mechnics

abstract:
  In a newly introduced time scale $\tau$, much smaller than the usual $t$, any
object is assumed to be a point-like particle, having a definite position. It
fluctuates without dynamics and the wave function $\Psi$ is defined by
averaging the square root of the density. In $t$-scale, the Schr$\ddot{\rm
o}$dinger equation holds and for a macrovariable just a classical path is
picked up as a peak of $\Psi$ by the stationary phase, which is the observable
signal. In the measuring process, the stationary phase branches into many but
one branch is selected by underlying determinism, leading to the correct
detection probability.


title:
First principles study of Sc, Ti and V doped Na$_n$(n =4, 5, 6)
  clusters: Enhanced magnetic moments

abstract:
  Theoretical studies on the geometry, electronic structure and spin
multiplicity of Sc, Ti and V doped Na$_n$ (n = 4, 5, 6) clusters have been
carried out within a gradient corrected density functional approach. Two
complementary approaches including all-electron calculations on free clusters,
and supercell calculations using planewave pseudopotential and projector
augmented wave formalisms have been carried out. It is shown that spin magnetic
moments of the transition metal atoms, the magnitude of host polarization, and
the sign of the host polarization all change with the number of alkali atoms.
In particular the transition metal atoms are shown to attain spin moments that
are higher than their atomic values. The role of hybridization between the
transition atom d-states and the alkali $sp$-states is highlighted to account
for the evolutions in the spin moments and host polarization.


title: Caldero-Keller approach to the denominators of cluster variables

abstract:
  Buan, Marsh and Reiten proved that if a cluster-tilting object $T$ in a
cluster category $\mathcal C$ associated to an acyclic quiver $Q$ satisfies
certain conditions with respect to the exchange pairs in $\mathcal C$, then the
denominator in its reduced form of every cluster variable in the cluster
algebra associated to $Q$ has exponents given by the dimension vector of the
corresponding module over the endomorphism algebra of $T$. In this paper, we
give an alternative proof of this result using the Caldero-Keller approach to
acyclic cluster algebras and the work of Palu on cluster characters.


title: On statistical methods of structure function extraction

abstract:
  Several methods of statistical analysis are proposed and analyzed in
application for a specific task -- extraction of the structure functions from
the cross sections of deep inelastic interactions of any type. We formulate the
method based on the orthogonal weight functions and on an optimization
procedure of errors minimization as well as methods underlying common $\chi^2$
minimization. Effectiveness of these methods usage is analyzed by comparison of
the statistical parameters such as bias, extraction variance etc., for sample
deep inelastic scattering data set.


title: Noncommutative Superspace and Super Heisenberg Group

abstract:
  In this paper, we consider noncommutative superspace in relation with super
Heisenberg group. We construct a matrix representation of super Heisenberg
group and apply this to the two-dimensional deformed N=(2,2) superspace that
appeared in string theory. We also construct a toy model for non-centrally
extended `super Heisenberg group'.


title: Instabilities in elastomers and soft tissues

abstract:
  Biological soft tissues exhibit elastic properties which can be dramatically
different from rubber-type materials (elastomers). To gain a better
understanding of the role of constitutive relationships in determining material
responses under loads we compare three different types of instabilities (two in
compression, one in extension) in hyperelasticity for various forms of strain
energy functions typically used for elastomers and for soft tissues.
Surprisingly, we find that the strain-hardening property of soft tissues does
not always stabilize the material. In particular we show that the stability
analyses for a compressed half-space and for a compressed spherical thick shell
can lead to opposite conclusions: a soft tissue material is more stable than an
elastomer in the former case and less stable in the latter case.


title:
Gauge theories with overlap fermions in an arbitrary representation:
  Evaluation of the 3-loop beta-function

abstract:
  This work presents the calculation of the relation between the bare coupling
constant g_0 and the MSbar-renormalized coupling g_MS, g_0 = Z_g(g_0,a\mu)
g_MS, to 2 loops in perturbation theory, with fermions in an arbitrary
representation of the gauge group SU(N). Our calculation is performed using
overlap fermions and Wilson gluons, and the background field technique has been
chosen for convenience. The corresponding results in the fundamental
representation appear in our longer publication [arXiv:0709.4368].
  The 3-loop coefficient of the bare beta-function, b_2^L, is extracted using
the 2-loop expression for Z_g, and it is presented as a function of the overlap
parameter rho, the number of fermion flavors (N_f) and the number of colors
(N). We also provide the expression for the ratio Lambda_L/Lambda_MS, in an
arbitrary representation. A plot of Lambda_L/Lambda_MS is given in the adjoint
representation.


title:
The instability of counter-propagating kernel gravity waves in a
  constant shear flow

abstract:
  The mechanism describing the recently developed notion of kernel gravity
waves (KGWs) is reviewed and such structures are employed to interpret the
unstable dynamics of an example stratified plane parallel shear flow. This flow
has constant vertical shear, is infinite in the vertical extent, and
characterized by two density jumps of equal magnitude each decreasing
successively with height, in which the jumps are located symmetrically away
from the midplane of the system. We find that for a suitably defined
bulk-Richardson number there exists a band of horizontal wavenumbers which
exhibits normal-mode instability. The instability mechanism closely parallels
the mechanism responsible for the instability seen in the problem of
counter-propagating Rossby waves. In this problem the instability arises out of
the interaction of counter-propagating gravity waves. We argue that the
instability meets the Hayashi-Young criterion for wave instability. We also
argue that the instability is the simplest one that can arise in a stratified
atmosphere with constant shear flow. The counter propagating gravity waves
mechanism detailed here explains why the Rayleigh criteria for shear flow
instability in the unstratified case does not need to be satisfied in the
stratified case. This illustrates how the Miles-Howard theorem may support
destabilization through stratification. A normal mode analysis of a foamy layer
consisting of two density jumps of unequal magnitude is also analyzed. The
results are considered in terms of observations made of sea-hurricane
interfaces.


title: A magnetic lens for cold atoms controlled by a rf field

abstract:
  We report on a new type of magnetic lens that focuses atomic clouds using a
static inhomogeneous magnetic field in combination with a radio-frequency
field. The experimental study is performed with a cloud of cold cesium atoms.
The rf field adiabatically deforms the magnetic potential of a coil and
therefore changes its focusing properties. The focal length can be tuned
precisely by changing the rf frequency value. Depending on the rf antenna
position relative to the DC magnetic profile, the focal length of the atomic
lens can be either decreased or increased by the rf field.


title:
Polymer nanoparticles to decrease thermal conductivity of phase change
  materials

abstract:
  Microparticles including paraffin are currently used for textiles coating in
order to deaden thermal shocks. We will show that polymer nanoparticles
embedded in those microsized capsules allow for decreasing the thermal
conductivity of the coating and enhance the protection in the stationary
regime. A reasonable volume fraction of polymer nanoparticles reduces the
conductivity more than predicted by Maxwell mixing rules. Besides, measurements
prove that the polymer nanoparticles do not affect the latent heat and even
improve the phase change behaviour as well as the mechanical properties.


title:
DFT calculation for adatom adsorption on graphene sheet as a prototype
  of carbon nano tube functionalization

abstract:
  DFT calculation of various atomic species on graphene sheet is investigated
as prototypes for formation of nano-structures on carbon nanotube (CNT) wall.
We investigate computationally adsorption energies and adsorption sites on
graphene sheet for a lot of atomic species including transition metals, noble
metals, nitrogen and oxygen, using the DFT calculation as a prototype for CNT.
The suitable atomic species can be chosen as each application from those
results. The calculated results show us that Mo and Ru are bounded strongly on
graphene sheet with large diffusion barrier energy. On the other hand, some
atomic species has large binding energies with small diffusion barrier energies


title: Automorphism groups of root systems matroids

abstract:
  Given a root system $\mathsf{R}$, the vector system $\tilde{\mathsf{R}}$ is
obtained by taking a representative $v$ in each antipodal pair $\{v, -v\}$. The
matroid $M(\mathsf{R})$ is formed by all independent subsets of
$\tilde{\mathsf{R}}$. The automorphism group of a matroid is the group of
permutations preserving its independent subsets. We prove that the automorphism
groups of all irreducible root systems matroids $M(\mathsf{R})$ are uniquely
determined by their independent sets of size 3. As a corollary, we compute
these groups explicitly, and thus complete the classification of the
automorphism groups of root systems matroids.


title: Duality Symmetry and the Cardy Limit

abstract:
  We study supersymmetric and non-supersymmetric extremal black holes obtained
in Type IIA string theory compactified on K3 X T^2, with duality group
O(6,22,Z) X SL(2,Z). In the Cardy limit an internal circle combines with the
AdS_2 component in the near horizon geometry to give a BTZ black hole whose
entropy is given by the Cardy formula. We study black holes carrying D0-D4 and
D0-D6 brane charges. We find, both in the supersymmetric and non-supersymmetric
cases, that a generic set of charges cannot be brought to the Cardy limit using
the duality symmetries. In the non-supersymmetric case, unlike the
supersymmetric one, we find that when the charges are large, a small fractional
change in them always allows the charges to be taken to the Cardy limit. These
results could lead to a microscopic determination of the entropy for extremal
non-supersymmetric black holes, including rotating cases like the extreme Kerr
black hole in four dimensions.


title: Coherent J/psi production - a novel feature at LHC?

abstract:
  Energy dependence of heavy quarkonia production in hadron-nucleus collisions
is studied in the framework of the Glauber-Gribov theory. We emphasize a change
in the space-time picture of heavy-quark state production on nuclei with
energy. Longitudinally ordered scattering of a heavy-quark system takes place
at low energies, while with increasing energy it transforms to a coherent
scattering of projectile partons on the nuclear target. The characteristic
energy scale for this transition depends on masses and rapidities of produced
particles. For J/psi, produced in the central rapidity region, the transition
happens at RHIC energies. The parameter-free calculation of J/psi in dAu
collisions is in good agreement with recent RHIC data. We use distributions of
gluons in nuclei to predict suppression of heavy quarkonia at LHC.


title:
On features of the radiation from an electron moving along a helix
  inside a cylindrical hole in a homogeneous dielectric

abstract:
  The radiation from a charge moving along a helical trajectory inside a
cylindrical hole in homogeneous dielectric medium is investigated. Prompted by
availability of materials with large dielectric permittivity $\epsilon $ and
small absorption, we discuss the features of this type of radiation for media
with $\epsilon \gg 1$. It is shown that there are high peaks in the angular
distribution of radiation intensity at well-defined harmonics. The conditions
are specified for the cavity-to-helix radii ratio, $\rho_{1}/\rho_{0}$, under
which the angle-integrated radiation intensity on some harmonics exceeds that
in the empty space. Though the amplification of radiation intensity increases
with increasing $\epsilon $, the corresponding "resonant" values of $\rho
_{1}/\rho_{0}$ ratio are practically independent of the dielectric permittivity
of surrounding medium. It is shown that an analogous amplification of radiation
takes place essentially for the same values of $\rho_{1}/\rho_{0}$ also for the
radiation in a cylindrical waveguide with conducting walls. An explanation of
this phenomenon is given.


title: Holst Actions for Supergravity Theories

abstract:
  Holst action containing Immirzi parameter for pure gravity is generalised to
the supergravity theories. Supergravity equations of motion are not modified by
such generalisations, thus preserving supersymmetry. Dependence on the Immirzi
parameter does not emerge in the classical equations of motion. This is in
contrast with the recent observation of Perez and Rovelli for gravity action
containing original Holst term and a minimally coupled Dirac fermion where the
classical equations of motion do develop a dependence on Immirzi parameter.


title: Discovery of the upper kilo-Hz QPO from the X-ray transient Aql X-1

abstract:
  We report on a comprehensive analysis of the kilo-Hz (>~600 Hz)
quasi-periodic oscillations (kHz QPOs) detected from the neutron star X-ray
transient Aquila X-1 (Aql X-1) with the Rossi X-ray Timing Explorer, between
1997 and 2007. Among kHz QPO sources, Aql X-1 is peculiar because so far only
one kHz QPO has been reported, whereas in most sources, two kHz QPOs are
usually detected (a lower and an upper kHz QPO). The identification of the QPOs
reported so far has therefore been ambiguous, although it has been proposed
that they were likely to be the lower QPO. Following up on previous work, we
confirm the identification of the QPOs previously reported as lower QPOs,
because of their high quality factors and the quality factor versus frequency
dependency, which are similar to those observed in other sources. Combining all
segments of data containing a lower QPO, we detect for the first time an upper
kHz QPO. As in other sources for which the neutron star spin frequency is
larger than 400 Hz (550.25 Hz in Aql X-1), the frequency difference between the
two kHz QPOs is close to half the spin frequency. Based on this result, we
re-examine the link between the neutron star spin and the frequency of the kHz
QPOs, to show that a model in which the separation of the lower and upper QPOs
relates to the neutron star spin frequency is still as good as any comparably
simple model.


title:
Folding ion rays in comet C/2004 Q2 (Machholz) and the connection with
  the solar wind

abstract:
  The appearance of folding ion rays in cometary comae is still not very well
understood, so our aim is to gain more insight into the role of the local solar
wind in the formation of these structures. Comet C/2004 Q2 (Machholz) was
intensively monitored during its closest approach to Earth (January 2005) with
the CCD camera Merope mounted on the Flemish 1.2m Mercator telescope, in three
different bands (Geneva U and B and Cousins I). Spectacular ion rays, thin
ionic structures rapidly folding tailward, were recorded in the U band during
one night, January 12th. Data from the SOHO satellite that was extrapolated
corotationally to the position of the comet showed that the ion rays were
formed during a sudden change in the in-situ solar wind state. We were able to
succesfully correlate a high-speed solar wind stream with the appearance of
folding ion rays. To our knowledge, this is the first clear observational
evidence that folding ion rays in cometary comae are produced by a sudden
change in the local solar wind state.


title:
Reply to the Comment on "Influence of protons on the capture of
  electrons by the nuclei of 7Be in the Sun"

abstract:
  We show that the arguments against our paper raised by B. Davids et al. are
either irrelevant or incorrect.