title:
Effect of Rb and Cs-doping on superconducting properties of MgB2 thin
  films

abstract:
  Our Rutherford backscattering spectrometry (RBS) study has found that
concentrations up to 7 atomic percent of Rb and Cs can be introduced to a depth
of ~700 A in MgB2 thin films by annealing in quartz ampoules containing
elemental alkali metals at <350 degree centigrade. No significant change in
transition temperature (Tc) was observed, in contrast to an earlier report of
very high Tc (>50 K) for similar experiments on MgB2 powders. The lack of a
significant change in Tc and intra-granular carrier scattering suggests that Rb
and Cs diffuse into the film, but do not enter the grains. Instead, the
observed changes in the electrical properties, including a significant drop in
Jc and an increase in delta rho (rho300-rho40), arise from a decrease in
inter-granular connectivity due to segregation of the heavy alkaline metals and
other impurities (i.e. C and O) introduced into the grain boundary regions
during the anneals.


title: Single-electron latch with granular film charge leakage suppressor

abstract:
  A single-electron latch is a device that can be used as a building block for
Quantum-dot Cellular Automata (QCA) circuits. It consists of three nanoscale
metal "dots" connected in series by tunnel junctions; charging of the dots is
controlled by three electrostatic gates. One very important feature of a
single-electron latch is its ability to store ("latch") information represented
by the location of a single electron within the three dots. To obtain latching,
the undesired leakage of charge during the retention time must be suppressed.
Previously, to achieve this goal, multiple tunnel junctions were used to
connect the three dots. However, this method of charge leakage suppression
requires an additional compensation of the background charges affecting each
parasitic dot in the array of junctions. We report a single-electron latch
where a granular metal film is used to fabricate the middle dot in the latch
which concurrently acts as a charge leakage suppressor. This latch has no
parasitic dots, therefore the background charge compensation procedure is
greatly simplified. We discuss the origins of charge leakage suppression and
possible applications of granular metal dots for various single-electron
circuits.


title:
Physicochemical influences on electrohydrodynamic transport in
  compressible packed beds of colloidal boehmite particles

abstract:
  Production and processing of colloidal particles require a deeper
understanding of surface charge of particles and interaction of mass and charge
transport in packed beds. The assessment of fundamental parameters is rather
complex due to the additional influence of the particle charge on the structure
of a packed bed. The combination of different measurement techniques (streaming
potential and electroosmosis) allows for separating the effects, based on the
postulation of a new method to quantify the ratio of surface conductance to
liquid conductance. The purpose of this paper is to investigate the influence
of the pH value and compression on the electrohydrodynamic transport
parameters.


title:
Muon internal bremsstrahlung: a conventional explanation for the excess
  electron-neutrino events in MiniBoone

abstract:
  We show that the rate of charged-current muon-neutrino events with a hard
internal bremsstrahlung photon is consistent with the excess electron-neutrino
candidate events reported by the MiniBoone and LSND (decay in flight)
experiments. Hard photons radiated by the muon leg in charged-current neutrino
interactions (neutrino-Nucleon->muon+gamma+nucleon) are a significant source of
background that should be considered by current and future muon-neutrino to
electron-neutrino neutrino oscillations appearance experiments (e.g. LSND,
MiniBoone, SuperK, MINOS, T2K and NOVA).


title: Gravitational lensing

abstract:
  This is a short and biased review of gravitational lensing with emphasis on
the radio and especially VLBI aspects. We briefly explain the basic idea and
give a short sketch of the discovery of the first lens, before we more
systematically discuss the general fields that can be studied with lensing. We
intentionally omit the details the average lensing expert would like to see and
instead try to give a very general overview addressed to the radio astronomer
working in some other field. The lens B0218+357 is presented as an example to
show many aspects of lensing in a case that already has led to interesting
results but still has additional potential for the future.


title: The VERITAS standard data analysis

abstract:
  VERITAS is an array of Imaging Atmospheric Cherenkov Telescopes designed for
very high energy gamma ray (E>100,GeV) observations of astrophysical sources.
  The experiment began its scientific observation program in the 2006/2007
observing season. We describe here the analysis chain for reducing the data,
reconstructing the direction and energy of incident gamma rays and the
rejection of background cosmic rays.


title: Effect of stoichiometry on oxygen incorporation in MgB2 thin films

abstract:
  The amount of oxygen incorporated into MgB2 thin films upon exposure to
atmospheric gasses is found to depend strongly on the material's stoichiometry.
Rutherford backscattering spectroscopy was used to monitor changes in oxygen
incorporation resulting from exposure to: (a) ambient atmosphere, (b) humid
atmospheres, (c) anneals in air and (d) anneals in oxygen. The study
investigated thin-film samples with compositions that were systematically
varied from Mg0.9B2 to Mg1.1B2. A significant surface oxygen contamination was
observed in all of these films. The oxygen content in the bulk of the film, on
the other hand, increased significantly only in Mg rich films and in films
exposed to humid atmospheres.


title:
System Size, Energy and Centrality Dependence of Pseudorapidity
  Distributions of Charged Particles in Relativistic Heavy Ion Collisions

abstract:
  We present the first measurements of the pseudorapidity distribution of
primary charged particles in Cu+Cu collisions as a function of collision
centrality and energy, \sqrtsnn = 22.4, 62.4 and 200 GeV, over a wide range of
pseudorapidity, using the PHOBOS detector. Making a global comparison of Cu+Cu
and Au+Au results, we find that the total number of produced charged particles
and the rough shape (height and width) of the pseudorapidity distributions are
determined by the number of nucleon participants. More detailed studies reveal
that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity
distributions over the full range of pseudorapidity occurs for the same
Npart/2A value rather than the same Npart value. In other words, it is the
collision geometry rather than just the number of nucleon participants that
drives the detailed shape of the pseudorapidity distribution and its centrality
dependence at RHIC energies.


title:
Summary of studies of the eta meson production with polarized proton
  beam at COSY-11

abstract:
  We report on the COSY-11 measurements of the analysing power for the p(pol)p
--> ppeta reaction and interpret the results in the framework of the meson
exchange models.


title: Local search heuristics: Fitness Cloud versus Fitness Landscape

abstract:
  This paper introduces the concept of fitness cloud as an alternative way to
visualize and analyze search spaces than given by the geographic notion of
fitness landscape. It is argued that the fitness cloud concept overcomes
several deficiencies of the landscape representation. Our analysis is based on
the correlation between fitness of solutions and fitnesses of nearest solutions
according to some neighboring. We focus on the behavior of local search
heuristics, such as hill climber, on the well-known NK fitness landscape. In
both cases the fitness vs. fitness correlation is shown to be related to the
epistatic parameter K.


title: Measuring the Evolvability Landscape to study Neutrality

abstract:
  This theoretical work defines the measure of autocorrelation of evolvability
in the context of neutral fitness landscape. This measure has been studied on
the classical MAX-SAT problem. This work highlight a new characteristic of
neutral fitness landscapes which allows to design new adapted metaheuristic.


title:
Seismic Risk Scenario in Grenoble (FRANCE) Using Experimental Dynamic
  Properties of Buildings

abstract:
  Assessing the vulnerability of a large set of buildings using sophisticated
methods can be very time consuming and at a prohibitive cost, particularly for
a moderate seismic hazard country like France. We propose here a low-cost
analysis using an experimental approach to extract the elastic behaviour of
existing buildings. An elastic modal model is proposed for the different types
of building tested in Grenoble (France) thanks to their experimental modal
parameters (resonance frequencies, modal shapes and damping), which are
estimated using ambient vibrations surveys. Sixty buildings of various types
were recorded. The building integrity is then calculated considering an
accelerogram scenario provided by seismologists as input and considering an
integrity threshold based on the FEMA inter-storey drift limits. Even if the
level of damage remains unknown, we conclude that masonry buildings undergo
more damage (70% of buildings damaged) than RC buildings. Finally, extracting
modal parameters from ambient vibration recordings allows us to define, for
each class of building, its ability to support seismic deformation in case of
earthquake.


title: Studying New Physics Amplitudes in Charmless B_s Decays

abstract:
  A method based on flavour SU(3) is proposed for identifying and extracting
New Physics (NP) amplitudes in charmless $\Delta S=1$ $B_s$ decays using
time-dependent CP asymmetries in these decays and in flavour SU(3) related
$\Delta S=0$ decays. For illustration, we assume a hierarchy, $\sim 1: \lambda
: \lambda^2$ ($\lambda=0.2$), between a dominant $\Delta S=1$ penguin
amplitude, a NP amplitude and a Standard Model amplitude with weak phase
$\gamma$. An uncertainty from SU(3) breaking corrections, reduced by using
ratios of hadronic amplitudes, is further suppressed by a factor $\lambda$. We
discuss examples for pairs of decays into two neutral vector mesons,
$B_s\to\phi\phi, B_s\to\phi \bar K^{*0}$ and $B_s\to K^{*0}\bar K^{*0}, B^0\to
K^{*0}\bar K^{*0}$, where the magnitude of the NP amplitude, its weak and
strong phases can be determined.


title:
The Klein-Gordon equation with a generalized Hulthen potential in
  D-dimensions

abstract:
  An approximate solution of the Klein-Gordon equation for the general
Hulth\'en-type potentials in $D$-dimensions within the framework of an
approximation to the centrifugal term is obtained. The bound state energy
eigenvalues and the normalized eigenfunctions are obtained in terms of
hypergeometric polynomials.


title:
From Texts to Structured Documents: The Case of Health Practice
  Guidelines

abstract:
  This paper describes a system capable of semi-automatically filling an XML
template from free texts in the clinical domain (practice guidelines). The XML
template includes semantic information not explicitly encoded in the text
(pairs of conditions and actions/recommendations). Therefore, there is a need
to compute the exact scope of conditions over text sequences expressing the
required actions. We present in this paper the rules developed for this task.
We show that the system yields good performance when applied to the analysis of
French practice guidelines.


title:
An object that defies stereotypes. X-ray observations of SBS 1150+599A
  -- the binary nucleus of PN G135.9+55.9

abstract:
  We present X-ray observations of the close binary nucleus of the planetary
nebula PN G135.9+55.9 obtained with the XMM satellite. The nebula is the most
oxygen-poor PN known to date and is located in the Galactic halo. It is known
to harbor a close binary nucleus of which only one component can be observed in
optical-UV range. New X-ray observations show that the invisible component is a
very hot compact star. This finding allows us to reconstruct the immediate past
of the object and predict its future. The parameters of the binary components
we determine strongly suggest that the precursor was a symbiotic supersoft
X-ray source that finished its life by Roche lobe overflow. PN G135.9+55.9 is
an excelent candidate for a future type Ia supernova.


title:
Sufficient and Necessary Conditions for Semidefinite Representability of
  Convex Hulls and Sets

abstract:
  A set $S\subseteq \re^n$ is called to be {\it Semidefinite (SDP)}
representable if $S$ equals the projection of a set in higher dimensional space
which is describable by some Linear Matrix Inequality (LMI). The contributions
of this paper are: (i) For bounded SDP representable sets $W_1,...,W_m$, we
give an explicit construction of an SDP representation for
$\cv{\cup_{k=1}^mW_k}$. This provides a technique for building global SDP
representations from the local ones. (ii) For the SDP representability of a
compact convex semialgebraic set $S$, we prove sufficient condition: the
boundary $\bdS$ is positively curved, and necessary condition: $\bdS$ has
nonnegative curvature at smooth points and on nondegenerate corners. This
amounts to the strict versus nonstrict quasi-concavity of defining polynomials
on those points on $\bdS$ where they vanish. The gaps between them are $\bdS$
having positive versus nonnegative curvature and smooth versus nonsmooth
points. A sufficient condition bypassing the gaps is when some defining
polynomials of $S$ are sos-concave. (iii) For the SDP representability of the
convex hull of a compact nonconvex semialgebraic set $T$, we find that the
critical object is $\pt_cT$, the maximum subset of $\pt T$ contained in $\pt
\cv{T}$. We prove sufficient conditions for SDP representability: $\pt_cT$ is
positively curved, and necessary conditions: $\pt_cT$ has nonnegative curvature
at smooth points and on nondegenerate corners. The gaps between them are
similar to case (ii). The positive definite Lagrange Hessian (PDLH) condition
is also discussed.


title:
On the Lusternik-Schnirelmann category of spaces with 2-dimensional
  fundamental group

abstract:
  The following inequality
  \cat X\le \cat Y+\lceil\frac{hd(X)-r}{r+1}\rceil
  holds for every locally trivial fibration between $ANE$ spaces $f:X\to Y$
which admits a section and has the $r$-connected fiber where $hd(X)$ is the
homotopical dimension of $X$. We apply this inequality to prove that
  \cat X\le \lceil\frac{\dim X-1}{2}\rceil+cd(\pi_1(X))
  for every complex $X$ with $cd(\pi_1(X))\le 2$.


title:
Dissecting Subsecond Cadherin Bound States Reveals an Efficient Way for
  Cells to Achieve Ultrafast Probing of their Environment

abstract:
  Cells continuously probe their environment with membrane receptors, achieving
subsecond adaptation of their behaviour [1-3]. Recently, several receptors,
including cadherins, were found to bind ligands with a lifetime of order of one
second. Here we show at the single molecule level that homotypic C-cadherin
association involves transient intermediates lasting less than a few tens of
milliseconds. Further, these intermediates transitionned towards more stable
states with a kinetic rate displaying exponential decrease with piconewton
forces. These features enable cells to detect ligands or measure surrounding
mechanical behaviour within a fraction of a second, much more rapidly than was
previously thought.


title: Circuit theory for crossed Andreev reflection and nonlocal conductance

abstract:
  Nonlocal currents, in devices where two normal metal terminals are contacted
to a superconductor, are determined using the circuit theory of mesoscopic
superconductivity. We calculate the conductance associated with crossed Andreev
reflection and electron transfer between the two normal metal terminals, in
addition to the conductance from direct Andreev reflection and quasiparticle
tunneling. Dephasing and proximity effect are taken into account.


title: Luminosity determination for the quasi-free nuclear reactions

abstract:
  A method for the calculation of the luminosity for the proton-nucleus
collisions based on the quasi-free proton-proton scattering is presented. As an
example of application the integrated luminosity for the scattering of protons
off the deuteron target is determined for the experiment of the quasi-free pn
--> pneta reaction performed by means of the COSY-11 facility.


title: The Lieb-Liniger Model as a Limit of Dilute Bosons in Three Dimensions

abstract:
  We show that the Lieb-Liniger model for one-dimensional bosons with repulsive
$\delta$-function interaction can be rigorously derived via a scaling limit
from a dilute three-dimensional Bose gas with arbitrary repulsive interaction
potential of finite scattering length. For this purpose, we prove bounds on
both the eigenvalues and corresponding eigenfunctions of three-dimensional
bosons in strongly elongated traps and relate them to the corresponding
quantities in the Lieb-Liniger model. In particular, if both the scattering
length $a$ and the radius $r$ of the cylindrical trap go to zero, the
Lieb-Liniger model with coupling constant $g \sim a/r^2$ is derived. Our bounds
are uniform in $g$ in the whole parameter range $0\leq g\leq \infty$, and apply
to the Hamiltonian for three-dimensional bosons in a spectral window of size
$\sim r^{-2}$ above the ground state energy.


title: Brane Vector Phenomenology

abstract:
  Local oscillations of the brane world are manifested as masssive vector
fields. Their coupling to the Standard Model can be obtained using the method
of nonlinear realizations of the spontaneously broken higher dimensional
space-time symmetries, and to an extent, are model independent.
Phenomenological limits on these vector field parameters are obtained using LEP
collider data and dark matter constraints.


title: Shut up and calculate

abstract:
  I advocate an extreme "shut-up-and-calculate" approach to physics, where our
external physical reality is assumed to be purely mathematical. This brief
essay motivates this "it's all just equations" assumption and discusses its
implications.

categories: physics.pop-ph gr-qc hep-th math-ph math.MP


title: Uncovering the Chemical Signature of the First Stars in the Universe

abstract:
  The chemical abundance patterns observed in metal-poor Galactic halo stars
contain the signature of the first supernovae, and thus allows us to probe the
first stars that formed in the universe. We construct a theoretical model for
the early chemical enrichment history of the Milky Way, aiming in particular at
the contribution from pair-instability supernovae (PISNe). These are a natural
consequence of current theoretical models for primordial star formation at the
highest masses. However, no metal-poor star displaying the distinct PISN
signature has yet been observed. We here argue that this apparent absence of
any PISN signature is due to an observational selection effect. Whereas most
surveys traditionally focus on the most metal-poor stars, we predict that early
PISN enrichment tends to `overshoot', reaching enrichment levels of [Ca/H] ~=
-2.5 that would be missed by current searches. We utilize existing
observational data to place constraints on the primordial initial mass function
(IMF). The number fraction of PISNe in the primordial stellar population is
estimated to be <0.07, or ~< 40% by mass, assuming that metal-free stars have
masses in excess of 10 M_sun. We further predict, based on theoretical
estimates for the relative number of PISNe, that the expected fraction of
second generation stars below [Ca/H]=-2 with a dominant (i.e., >90%)
contribution from PISNe is merely ~1e-4 - 5e-4. The corresponding fraction of
stars formed from gas exclusively enriched by PISNe is a factor of ~4 smaller.
With the advent of next generation telescopes and new, deeper surveys, we
should be able to test these predictions.


title:
Recycling Matter in the Universe. X-ray observations of SBS 1150+599A
  (PN G135.9+55.9)

abstract:
  We present X-ray observations of the close binary nucleus of the planetary
nebula SBS 1150+599A obtained with the XMM-Newton satellite. Only one component
of the binary can be observed in optical-UV. New X-ray observations show that
the previously invisible component is a very hot compact star. This finding
allows us to deduce rough values for the basic parameters of the binary. With a
high probability the total mass of the system exceeds Chandrasekhar limit and
makes the SBS 1150+599A one of the best candidate for a supernova type Ia
progenitor.


title:
On the Structure of Dark Matter Halos at the Damping Scale of the Power
  Spectrum with and without Relict Velocities

abstract:
  We report a series of high-resolution cosmological N-body simulations
designed to explore the formation and properties of dark matter halos with
masses close to the damping scale of the primordial power spectrum of density
fluctuations. We further investigate the effect that the addition of a random
component, v_rms, into the particle velocity field has on the structure of
halos. We adopted as a fiducial model the Lambda Warm Dark Matter cosmology
with a non-thermal sterile neutrino mass of 0.5 keV. The filtering mass
corresponds then to M_f = 2.6x10^12 M_sun/h. Halos of masses close to M_f were
simulated with several million of particles. The results show that, on one
hand, the inner density slope of these halos (at radii <~0.02 the virial radius
Rvir) is systematically steeper than the one corresponding to the NFW fit or to
the CDM counterpart. On the other hand, the overall density profile (radii
larger than 0.02Rvir) is less curved and less concentrated than the NFW fit,
with an outer slope shallower than -3. For simulations with v_rms, the inner
halo density profiles flatten significantly at radii smaller than 2-3 kpc/h
(<~0.010-0.015Rvir). A constant density core is not detected in our
simulations, with the exception of one halo for which the flat core radius is
~1 kpc/h. Nevertheless, if ``cored'' density profiles are used to fit the halo
profiles, the inferred core radii are ~0.1-0.8 kpc/h, in rough agreement with
theoretical predictions based on phase-space constrains, and on dynamical
models of warm gravitational collapse. A reduction of v_rms by a factor of 3
produces a modest decrease in core radii, less than a factor of 1.5. We discuss
the extension of our results into several contexts, for example, to the
structure of the cold DM micro-halos at the damping scale of this model.


title: D-branes and Normal Functions

abstract:
  We explain the B-model origin of extended Picard-Fuchs equations satisfied by
the D-brane superpotential on compact Calabi-Yau threefolds. Via the
Abel-Jacobi map, the domainwall tension is identified with a Poincare normal
function--a transversal holomorphic section of the Griffiths intermediate
Jacobian. Within this formalism, we derive the extended Picard-Fuchs equation
associated with the mirror of the real quintic.


title:
Self Calibration of Tomographic Weak Lensing for the Physics of Baryons
  to Constrain Dark Energy

abstract:
  Numerical studies indicate that uncertainties in the treatment of baryonic
physics can affect predictions for shear power spectra at a level that is
significant for forthcoming surveys such as DES, SNAP, and LSST.
Correspondingly, we show that baryonic effects can significantly bias dark
energy parameter measurements. Eliminating such biases by neglecting
information in multipoles beyond several hundred leads to weaker parameter
constraints by a factor of approximately 2 to 3 compared with using information
out to multipoles of several thousand. Fortunately, the same numerical studies
that explore the influence of baryons indicate that they primarily affect power
spectra by altering halo structure through the relation between halo mass and
mean effective halo concentration. We explore the ability of future weak
lensing surveys to constrain both the internal structures of halos and the
properties of the dark energy simultaneously as a first step toward self
calibrating for the physics of baryons. This greatly reduces parameter biases
and no parameter constraint is degraded by more than 40% in the case of LSST or
30% in the cases of SNAP or DES. Modest prior knowledge of the halo
concentration relation greatly improves even these forecasts. Additionally, we
find that these surveys can constrain effective halo concentrations near
m~10^14 Msun/h and z~0.2 to better than 10% with shear power spectra alone.
These results suggest that inferring dark energy parameters with measurements
of shear power spectra can be made robust to baryonic effects and may
simultaneously be competitive with other methods to inform models of galaxy
formation. (Abridged)


title: The Low-z Intergalactic Medium. III. HI and Metal Absorbers at z<0.4

abstract:
  We conduct an ultraviolet (HST and FUSE) spectroscopic survey of HI (Lyman
lines) and seven metal ions (OVI, NV, CIV, CIII, SiIV, SiIII, FeIII) in the
low-redshift intergalactic medium (IGM) at z<0.4. We analyzed 650 Lya absorbers
over redshift pathlength Delta z=5.27, detecting numerous absorbers: 83 OVI
systems, 39 CIII, 53 SiIII, 24 CIV, 24 NV, and so on. Our survey yields
distributions in column density and estimates of the IGM baryon content and
metallicities of C, N, O in the IGM. In the low-z IGM, we have accounted for
~40% of the baryons: 30% in the photoionized Lya forest and 10% in the
(T=10^5-6 K) warm-hot intergalactic medium (WHIM) traced by OVI. Statistical
metallicities of C, N, O ions are consistent with the canonical (z=0) value of
10% solar, with considerable scatter. Improved statistics for weak OVI
absorbers allows us to estimate Omega_WHIM/Omega_b=0.073+-0.008 down to
logN_OVI=13.4. NV absorption is well-correlated with OVI and both ions show
similarly steep power-law indices dN/dz N^-beta with beta_OVI beta_NV 2 while
beta_HI=1.7. We conclude that OVI and NV are reliable tracers of the portion of
the WHIM at T=10^5-6 K. CIV may be present in both collisional and photoionized
phases; N_CIV correlates poorly with both N_HI and N_OVI and
beta_HI<beta_CIV<beta_OVI. The ions CIII, SiIII, and SiIV are well correlated
with HI and show patterns typical of photoionization. Adjacent ion stages of
the same element (CIII/IV and SiIII/IV) provide useful constraints on the
photoionization parameter, logU=-1.5+-0.5. Comparison of SiIV and CIV with
high-z surveys shows a modest increase in line density, consistent with
increasing IGM metallicity at recent epochs.


title: Infinite products with strongly $B$-multiplicative exponents

abstract:
  Let $N_{1,B}(n)$ denote the number of ones in the $B$-ary expansion of an
integer $n$. Woods introduced the infinite product $P :=\prod_{n \geq 0}
(\frac{2n+1}{2n+2})^{(-1)^{N_{1,2}(n)}}$ and Robbins proved that $P =
1/\sqrt{2}$. Related products were studied by several authors. We show that a
trick for proving that $P^2 = 1/2$ (knowing that $P$ converges) can be extended
to evaluating new products with (generalized) strongly $B$-multiplicative
exponents. A simple example is $$ \prod_{n \geq 0}
(\frac{Bn+1}{Bn+2})^{(-1)^{N_{1,B}(n)}} = \frac{1}{\sqrt B}. $$


title:
High-resolution saturation spectroscopy of singly-ionized iron with a
  pulsed uv laser

abstract:
  We describe the design and realization of a scheme for uv laser spectroscopy
of singly-ionized iron (Fe II) with very high resolution. A buffer-gas cooled
laser ablation source is used to provide a plasma close to room temperature
with a high density of Fe II. We combine this with a scheme for pulsed-laser
saturation spectroscopy to yield sub-Doppler resolution. In a demonstration
experiment, we have examined an Fe II transition near 260 nm, attaining a
linewidth of about 250 MHz. The method is well-suited to measuring transition
frequencies and hyperfine structure. It could also be used to measure small
isotope shifts in isotope-enriched samples.


title: Large Winding Sector of AdS/CFT

abstract:
  We study a family of classical strings on R x S^3 subspace of the AdS_5 x S^5
background that interpolates between pulsating strings and single-spike
strings. They are obtained from the helical strings of hep-th/0609026 by
interchanging worldsheet time and space coordinates, which maps
rotating/spinning string states with large spins to oscillating states with
large winding numbers. From a finite-gap perspective, this transformation is
realised as an interchange of quasi-momentum and quasi-energy defined for the
algebraic curve. The gauge theory duals are also discussed, and are identified
with operators in the non-holomorphic sector of N=4 super Yang-Mills. They can
be viewed as excited states above the ``antiferromagnetic'' state, which is
``the farthest from BPS'' in the spin-chain spectrum. Furthermore, we
investigate helical strings on AdS_3 x S^1 in an appendix.


title: Search for Proton Medium Modifications in the 4He(e,e'p)3H Reaction

abstract:
  Polarization transfer in quasi-elastic nucleon knockout is sensitive to the
properties of the nucleon in the nuclear medium, including possible
modification of the nucleon form factor and/or spinor. In our recently
completed experiment E03-104 at Jefferson Lab we measured the proton recoil
polarization in the 4He(e,e'p)3H reaction at a Q^2 of 0.8 (GeV/c)^2 and 1.3
(GeV/c)^2 with unprecedented precision. These data complement earlier data
between 0.4 and 2.6 (GeV/c)^2 from both Mainz and Jefferson Lab. The measured
ratio of polarization-transfer coefficients differs from a fully relativistic
calculation, favoring either the inclusion of a medium modification of the
proton form factors predicted by a quark-meson coupling model or strong
charge-exchange final-state interactions. The measured induced polarizations
agree well with the fully relativistic calculation and indicate that these
strong final-state interactions may not be applicable.


title:
Energy Efficient Estimation of Gaussian Sources Over Inhomogeneous
  Gaussian MAC Channels

abstract:
  It has been shown lately the optimality of uncoded transmission in estimating
Gaussian sources over homogeneous/symmetric Gaussian multiple access channels
(MAC) using multiple sensors. It remains, however, unclear whether it still
holds for any arbitrary networks and/or with high channel signal-to-noise ratio
(SNR) and high signal-to-measurement-noise ratio (SMNR). In this paper, we
first provide a joint source and channel coding approach in estimating Gaussian
sources over Gaussian MAC channels, as well as its sufficient and necessary
condition in restoring Gaussian sources with a prescribed distortion value. An
interesting relationship between our proposed joint approach with a more
straightforward separate source and channel coding scheme is then established.
We then formulate constrained power minimization problems and transform them to
relaxed convex geometric programming problems, whose numerical results exhibit
that either separate or uncoded scheme becomes dominant over a linear topology
network. In addition, we prove that the optimal decoding order to minimize the
total transmission powers for both source and channel coding parts is solely
subject to the ranking of MAC channel qualities, and has nothing to do with the
ranking of measurement qualities. Finally, asymptotic results for homogeneous
networks are obtained which not only confirm the existing optimality of the
uncoded approach, but also show that the asymptotic SNR exponents of these
three approaches are all the same. Moreover, the proposed joint approach share
the same asymptotic ratio with respect to high SNR and high SMNR as the uncoded
scheme.


title: Resolved Sideband Cooling of a Micromechanical Oscillator

abstract:
  Micro- and nanoscale opto-mechanical systems provide radiation pressure
coupling of optical and mechanical degree of freedom and are actively pursued
for their ability to explore quantum mechanical phenomena of macroscopic
objects. Many of these investigations require preparation of the mechanical
system in or close to its quantum ground state. Remarkable progress in ground
state cooling has been achieved for trapped ions and atoms confined in optical
lattices. Imperative to this progress has been the technique of resolved
sideband cooling, which allows overcoming the inherent temperature limit of
Doppler cooling and necessitates a harmonic trapping frequency which exceeds
the atomic species' transition rate. The recent advent of cavity back-action
cooling of mechanical oscillators by radiation pressure has followed a similar
path with Doppler-type cooling being demonstrated, but lacking inherently the
ability to attain ground state cooling as recently predicted. Here we
demonstrate for the first time resolved sideband cooling of a mechanical
oscillator. By pumping the first lower sideband of an optical microcavity,
whose decay rate is more than twenty times smaller than the eigen-frequency of
the associated mechanical oscillator, cooling rates above 1.5 MHz are attained.
Direct spectroscopy of the motional sidebands reveals 40-fold suppression of
motional increasing processes, which could enable reaching phonon occupancies
well below unity (<0.03). Elemental demonstration of resolved sideband cooling
as reported here should find widespread use in opto-mechanical cooling
experiments. Apart from ground state cooling, this regime allows realization of
motion measurement with an accuracy exceeding the standard quantum limit.


title: On Log Canonical Models of the Moduli Space of Stable Pointed Curves

abstract:
  We study the log canonical models of the moduli space MBar_{0,n} of pointed
stable genus zero curves with respect to the standard log canonical divisors
K+aD, where D denotes the boundary. In particular we show that, as a formal
consequence of a conjecture by Fulton regarding the ample cone of MBar_{0,n},
these log canonical models are equal to certain of Hassett's weighted pointed
curve spaces.


title: Quantum theory of an accelerating universe

abstract:
  We review some of the well-known features of quantum cosmology, such as the
factor ordering problem, the wave function and the density matrix, for a dark
energy dominated universe, where analytical solutions can be obtained. For the
particular case of the phantom universe, we suggest a quantum system in which
the usual notion of locality (non-locality) of quantum information theory have
to be extended. In that case, we deal also with a quantum description where the
existence of a non-chronal region around the big rip singularity is explicitly
accounted for.


title: (\omega, \phi) P^- decays of tau leptons

abstract:
  The \tau -> (\omega, \phi)P^-\nu decays, where P^-=\pi^-, K^-, are considered
within a phenomenological model with dominance of meson intermediate states. We
assume SU(3) flavor symmetry to fix some of the unknown strong interaction
couplings. Our predictions for the \tau -> \phi (\pi^-, K^-)\nu branching
fractions are in good agreement with recent measurements of the BABAR and BELLE
Collaborations.


title: Observing the evolution of the CMB

abstract:
  Most cosmological parameters are expected to change significantly only on
cosmological time scales, but given the large amount of information contained
within the Cosmic Microwave Background (CMB) sky, we can expect that changes in
the CMB should be observable on much shorter time scales. Here we quantify this
expectation, examining the detectability of the dominant effects on short time
scales. We find that an ideal future experiment with currently achievable
sensitivity could detect the changing dipole due to our galactic motion in
about 10 years, but that it would take around 4000 years to detect a change in
the higher order multipoles.


title: A Generalization of De Vries Duality Theorem

abstract:
  Generalizing Duality Theorem of H. de Vries, we define a category which is
dually equivalent to the category of all locally compact Hausdorff spaces and
all perfect maps between them.


title: Lack of consensus in social systems

abstract:
  We propose an exactly solvable model for the dynamics of voters in a
two-party system. The opinion formation process is modeled on a random network
of agents. The dynamical nature of interpersonal relations is also reflected in
the model, as the connections in the network evolve with the dynamics of the
voters. In the infinite time limit, an exact solution predicts the emergence of
consensus, for arbitrary initial conditions. However, before consensus is
reached, two different metastable states can persist for exponentially long
times. One state reflects a perfect balancing of opinions, the other reflects a
completely static situation. An estimate of the associated lifetimes suggests
that lack of consensus is typical for large systems.


title: Scaling and dynamics of sphere and disk impact into granular media

abstract:
  Direct measurements of the acceleration of spheres and disks impacting
granular media reveal simple power law scalings along with complex dynamics
which bear the signatures of both fluid and solid behavior. The penetration
depth scales linearly with impact velocity while the collision duration is
constant for sufficiently large impact velocity. Both quantities exhibit power
law dependence on sphere diameter and density, and gravitational acceleration.
The acceleration during impact is characterized by two jumps: a rapid, velocity
dependent increase upon initial contact and a similarly sharp, depth dependent
decrease as the impacting object comes to rest. Examining the measured forces
on the sphere in the vicinity of these features leads to a new experimentally
based granular force model for collision. We discuss our findings in the
context of recently proposed phenomenological models that capture qualitative
dynamical features of impact but fail both quantitatively and in their
inability to capture significant acceleration fluctuations that occur during
penetration and which depend on the impacted material.


title: NLO QCD corrections to the production of t-tbar-Z in gluon fusion

abstract:
  We compute the O(alpha_s) QCD corrections to the partonic process gg ->
t-tbar-Z at the LHC. This partonic channel is the dominant component of the
scattering process pp -> t-tbar-Z, which will be important for measuring the
t-tbar-Z electroweak couplings. The O(alpha_s) corrections increase the total
cross section by up to 75% for reasonable choices of the renormalization and
factorization scales. Inclusion of these contributions descreases the residual
scale dependence of the cross section coming from uncalculated higher order
terms to +-5%.


title: Chaotic Dynamics of Spin-Valve Oscillators

abstract:
  Recent experimental and theoretical studies on the magnetization dynamics
driven by an electric current have uncovered a number of unprecedented rich
dynamic phenomena. We predict an intrinsic chaotic dynamics that has not been
previously anticipated. We explicitly show that the transition to chaotic
dynamics occurs through a series of period doubling bifurcations. In chaotic
regime, two dramatically different power spectra, one with a well-defined peak
and the other with a broadly distributed noise, are identified and explained.


title:
Equivalence Theorems in Numerical Analysis : Integration,
  Differentiation and Interpolation

abstract:
  We show that if a numerical method is posed as a sequence of operators acting
on data and depending on a parameter, typically a measure of the size of
discretization, then consistency, convergence and stability can be related by a
Lax-Richtmyer type equivalence theorem -- a consistent method is convergent if
and only if it is stable. We define consistency as convergence on a dense
subspace and stability as discrete well-posedness. In some applications
convergence is harder to prove than consistency or stability since convergence
requires knowledge of the solution. An equivalence theorem can be useful in
such settings. We give concrete instances of equivalence theorems for
polynomial interpolation, numerical differentiation, numerical integration
using quadrature rules and Monte Carlo integration.


title: Herbig-Haro flows in B335

abstract:
  We have observed optical (Halpha and [SII]) and near-IR (S(1) line of H2)
deep fields and taken optical spectra using the 2.56m NOT, as well as a near-UV
deep field (U band) using the 3.58m NTT. In addition we present new SPITZER
(IRAC and MIPS) mid-IR observations. We use previous Halpha and S(1)
observations taken 15 and 9 years earlier to make proper motion maps. We then
investigate the shock physics by matching our spectra with planar shock models.
We discover six new HH objects in B335. From proper motions we find an
optically bright, roughly E-W oriented group with high space velocities
(200-280 km/s) and a near-IR bright, slower group (15-75 km/s) moving to the
ESE. We also find a system of at least 15 H2 knots in the western lobe. This
(WNW) counterflow suggests the possibility of a binary outflow source, giving
rise to two outflow axes with slightly different orientations. We find that the
E-W flow is symmetrical with evidence for two outbursts. We make the first
detection of [OI] 6300/63 in HH119 B and Hbeta in HH119 A and B and find their
extinctions to be AV~1.4 and 4.4, respectively. HH119 A is found to expand much
faster than expected from linear expansion with distance from the outflow
source. Using planar shock models we find shock velocities of ~60 km/s (A) and
~35 km/s (B and C). This agrees with A being of higher excitation than B and C.
In our U image we detect three of the HH objects and propose that the emission
arise from the [OII] 3728 line and the blue continuum. New SPITZER observations
show most of the HH objects at 4.5 micron and a E-W elongated hour-glass shaped
structure at the outflow source. Even at 24 micron it is not clear whether most
of the light is direct or reflected.


title: A Symphony Conducted by Brunet

abstract:
  We introduce BruNet, a general P2P software framework which we use to produce
the first implementation of Symphony, a 1-D Kleinberg small-world architecture.
Our framework is designed to easily implement and measure different P2P
protocols over different transport layers such as TCP or UDP. This paper
discusses our implementation of the Symphony network, which allows each node to
keep $k \le \log N$ shortcut connections and to route to any other node with a
short average delay of $O(\frac{1}{k}\log^2 N)$. %This provides a continuous
trade-off between node degree and routing latency. We present experimental
results taken from several PlanetLab deployments of size up to 1060 nodes.
These succes sful deployments represent some of the largest PlanetLab
deployments of P2P overlays found in the literature, and show our
implementation's robustness to massive node dynamics in a WAN environment.


title: Nonthermal Bremsstrahlung vs. Synchrotron Radiation: Cas A

abstract:
  We performed a spectral analysis of some Chandra ACIS and RXTE PCA data for
the supernova remnant Cas A. A very large (1.1 Ms) ACIS data set is used to
identify regions dominated by synchrotron radiation. The best-fit spectral
models for these regions are combined to obtain a composite synchrotron model
for the entire remnant. The difference between this model and the observed PCA
flux is fitted with a nonthermal bremsstrahlung model. The results of this
analysis suggest that (1) the ratio of the nonthermal bremsstrahlung to
synchrotron radiation varies from about 2:1 to 4:1 in the 10-32 keV energy
band, (2) the electron spectrum is significantly steeper at 10-32 keV than it
is at 1 GeV, (3) about 5% of the electrons are nonthermal and (4) about 30% of
the energy in the electron distribution is in nonthermal electrons.


title: Extended Gutzwiller Approximation for Inhomogeneous System

abstract:
  The generalization of the Gutzwiller approximation to inhomogeneous systems
is considered, with extra spin-and-site-dependent fugacity factors included. It
is found that the inclusion of fugacity factors reconciles the seemingly
contradictory choices of Gutzwiller factors used in the literature. Moreover,
from the derivation of the Gutzwiller factors, it is shown that the Gutzwiller
approximation breaks the rotational symmetry of the trial wavefunctions, and
that different components of the spin-spin interaction need to be renormalized
differently under the approximation. Various schemes to restore the rotational
symmetry are discussed and are compared with results from variational
Monte-Carlo calculations for the two-dimensional square-lattice
antiferromagnet. Results along different paths within the full parameter space,
which corresponds to different choices of fugacity factors in the literature,
are also compared.


title: Boring split links

abstract:
  Boring is an operation which converts a knot or two-component link in a
3--manifold into another knot or two-component link. It generalizes rational
tangle replacement and can be described as a type of 2--handle attachment.
Sutured manifold theory is used to study the existence of essential spheres and
planar surfaces in the exteriors of knots and links obtained by boring a split
link. It is shown, for example, that if the boring operation is complicated
enough, a split link or unknot cannot be obtained by boring a split link.
Particular attention is paid to rational tangle replacement. If a knot is
obtained by rational tangle replacement on a split link, and a few minor
conditions are satisfied, the number of boundary components of a meridional
planar surface is bounded below by a number depending on the distance of the
rational tangle replacement. This result is used to give new proofs of two
results of Eudave-Mu\~noz and Scharlemann's band sum theorem.


title:
Confocal microscopy of colloidal particles: towards reliable, optimum
  coordinates

abstract:
  Over the last decade, the light microscope has become increasingly useful as
a quantitative tool for studying colloidal systems. The ability to obtain
particle coordinates in bulk samples from micrographs is particularly
appealing. In this paper we review and extend methods for optimal image
formation of colloidal samples, which is vital for particle coordinates of the
highest accuracy, and for extracting the most reliable coordinates from these
images. We discuss in depth the accuracy of the coordinates, which is sensitive
to the details of the colloidal system and the imaging system. Moreover, this
accuracy can vary between particles, particularly in dense systems. We
introduce a previously unreported error estimate and use it to develop an
iterative method for finding particle coordinates. This individual-particle
accuracy assessment also allows comparison between particle locations obtained
from different experiments. Though aimed primarily at confocal microscopy
studies of colloidal systems, the methods outlined here should transfer readily
to many other feature extraction problems, especially where features may
overlap one another.


title:
Electroweak quark-lepton symmetry and weak topological-charge
  confinement in the Standard Model with Dirac neutrinos

abstract:
  The standard electroweak model with Dirac neutrinos is extended by way of the
principles of electroweak quark-lepton symmetry and weak topological-charge
confinement to account for quark-lepton charge relations which, if not
accidental, are indicative of charge structures. A mixing in quarks and leptons
of underlying integer local charges with integer weak topological charges
associated with an additive group Z_3, fixed by the anomaly cancellation
requirement, is discussed. It is found that the electroweak difference between
topological quarks and leptons is the nonequivalence between the topological
vacua of their weak field configurations, produced by a four-instanton which
carries the topological charge, induces the universal fractional piece of
charge distinguishing quarks from leptons, and breaks the underlying symmetry.
The constituent quarks of the standard model appear as coming from topological
quarks, via the weak four-instanton event. Dual transitions occur for leptons.
It is shown that several other fundamental problems left open in the standard
electroweak model with Dirac neutrinos are solved: the one-to-one
correspondence between quark and lepton flavors, the existence of three
generations, the conservation and ungauging of B-L, the electric charge
quantization, and the confinement of fractional electric charges.


title: The process gg -> h_0 -> gamma gamma in the Lee-Wick Standard Model

abstract:
  The process gg -> h_0 -> gamma gamma is studied in the Lee-Wick extension of
the Standard Model (LWSM) proposed by Grinstein, O'Connell and Wise. In this
model negative norm partners for each SM field are introduced with the aim to
cancel quadratic divergences in the Higgs mass. All sectors of the model
relevant to gg -> h_0 -> gamma gamma are diagonalized and results are commented
on from the perspective of both the Lee-Wick and higher derivative formalisms.
Deviations from the SM rate for gg -> h_0 are found to be of the order of 15% -
5% for Lee-Wick masses in the range 500GeV - 1000GeV. Effects on the rate for
h_0-> gamma gamma are smaller, of the order of 5% - 1% for Lee-Wick masses in
the same range. These comparatively small changes may well provide a means of
distinguishing the LWSM from other models such as universal extra dimensions
where same-spin partners to Standard Model fields also appear. Corrections to
determinations of CKM elements |V_{t(b,s,d)}| are also considered and are shown
to be positive, allowing the possibility of measuring a CKM element larger than
unity, a characteristic signature of the ghost-like nature of the Lee-Wick
fields.


title:
Next-to-Next-to-Leading Electroweak Logarithms in W-pair Production at
  ILC

abstract:
  We derive the high energy asymptotic behavior of gauge boson production cross
section in a spontaneously broken SU(2) gauge theory in the
next-to-next-to-leading logarithmic approximation. On the basis of this result
we obtain the logarithmically enhanced two-loop electroweak corrections to the
differential cross section of W-pair production at ILC/CLIC up to the second
power of the large logarithm.


title:
Detection of low energy single ion impacts in micron scale transistors
  at room temperature

abstract:
  We report the detection of single ion impacts through monitoring of changes
in the source-drain currents of field effect transistors (FET) at room
temperature. Implant apertures are formed in the interlayer dielectrics and
gate electrodes of planar, micro-scale FETs by electron beam assisted etching.
FET currents increase due to the generation of positively charged defects in
gate oxides when ions (121Sb12+, 14+, Xe6+; 50 to 70 keV) impinge into channel
regions. Implant damage is repaired by rapid thermal annealing, enabling
iterative cycles of device doping and electrical characterization for
development of single atom devices and studies of dopant fluctuation effects.


title: On the quantum dynamics of non-commutative systems

abstract:
  This is a review paper concerned with the global consistency of the quantum
dynamics of non-commutative systems. Our point of departure is the theory of
constrained systems, since it provides a unified description of the classical
and quantum dynamics for the models under investigation. We then elaborate on
recently reported results concerned with the sufficient conditions for the
existence of the Born series and unitarity and turn, afterwards, into analyzing
the functional quantization of non-commutative systems. The compatibility
between the operator and the functional approaches is established in full
generality. The intricacies arising in connection with the explicit computation
of path integrals, for the systems under scrutiny, is illustrated by presenting
the detailed calculation of the Feynman kernel for the non-commutative two
dimensional harmonic oscillator.


title: Locally toric manifolds and singular Bohr-Sommerfeld leaves

abstract:
  When geometric quantization is applied to a manifold using a real
polarization which is "nice enough", a result of Sniatycki says that the
quantization can be found by counting certain objects, called Bohr-Sommerfeld
leaves. Subsequently, several authors have taken this as motivation for
counting Bohr-Sommerfeld leaves when studying the quantization of manifolds
which are less "nice".
  In this paper, we examine the quantization of compact symplectic manifolds
that can locally be modelled by a toric manifold, using a real polarization
modelled on fibres of the moment map. We compute the results directly, and
obtain a theorem similar to Sniatycki's, which gives the quantization in terms
of counting Bohr-Sommerfeld leaves. However, the count does not include the
Bohr-Sommerfeld leaves which are singular. Thus the quantization obtained is
different from the quantization obtained using a Kaehler polarization.


title: Random multiparty entanglement distillation

abstract:
  We describe various results related to the random distillation of multiparty
entangled states - that is, conversion of such states into entangled states
shared between fewer parties, where those parties are not predetermined. In
previous work [Phys. Rev. Lett. 98, 260501 (2007)] we showed that certain
output states (namely Einstein-Podolsky-Rosen (EPR) pairs) could be reliably
acquired from a prescribed initial multipartite state (namely the W state) via
random distillation that could not be reliably created between predetermined
parties. Here we provide a more rigorous definition of what constitutes
``advantageous'' random distillation. We show that random distillation is
always advantageous for W-class three-qubit states (but only sometimes for
Greenberger-Horne-Zeilinger (GHZ)-class states). We show that the general class
of multiparty states known as symmetric Dicke states can be readily converted
to many other states in the class via random distillation. Finally we show that
random distillation is provably not advantageous in the limit of multiple
copies of pure states.


title: A Simple and Realistic Model of Supersymmetry Breaking

abstract:
  We present a simple and realistic model of supersymmetry breaking. In
addition to the minimal supersymmetric standard model, we only introduce a
hidden sector gauge group SU(5) and three fields X, F and \bar{F}.
Supersymmetry is broken at a local minimum of the potential, and its effects
are transmitted to the supersymmetric standard model sector through both
standard model gauge loops and local operators suppressed by the cutoff scale,
which is taken to be the unification scale. The form of the local operators is
controlled by a U(1) symmetry. The generated supersymmetry breaking and mu
parameters are comparable in size, and no flavor or CP violating terms arise.
The spectrum of the first two generation superparticles is that of minimal
gauge mediation with the number of messengers N_mess = 5 and the messenger
scale 10^11 GeV < M_mess < 10^13 GeV. The spectrum of the Higgs bosons and
third generation superparticles, however, can deviate from it. The lightest
supersymmetric particle is the gravitino with a mass of order (1-10) GeV.


title:
Scaling Analysis and Application: Phase Diagram of Magnetic Nanorings
  and Elliptical Nanoparticles

abstract:
  The magnetic properties of single-domain nanoparticles with different
geometric shapes, crystalline anisotropies and lattice structures are
investigated. A recently proposed scaling approach is shown to be universal and
in agreement with dimensional analysis coupled with an assumption of {\em
incomplete} self-similarity. It is used to obtain phase diagrams of magnetic
nanoparticles featuring three competing configurations: in-plane and
out-of-plane ferromagnetism and vortex formation. The influence of the vortex
core on the scaling behavior and phase diagram is analyzed. Three-dimensional
phase diagrams are obtained for cylindrical nanorings, depending on their
height, outer and inner radius. The triple points in these phase diagrams are
shown to be in linear relationship with the inner radius of the ring.
Elliptically shaped magnetic nanoparticles are also studied. A new
parametrization for double vortex configurations is proposed, and regions in
the phase diagram are identified where the double vortex is a stable ground
state.


title:
The Burst Spectra of EXO 0748-676 during a Long 2003 XMM-Newton
  Observation

abstract:
  Gravitationally redshifted absorption lines from highly ionized iron have
been previously identified in the burst spectra of the neutron star in EXO
0748-676. To repeat this detection we obtained a long, nearly 600 ks
observation of the source with XMM-Newton in 2003. The spectral features seen
in the burst spectra from the initial data are not reproduced in the burst
spectra from this new data. In this paper we present the spectra from the 2003
observations and discuss the sensitivity of the absorption structure to changes
in the photospheric conditions.


title: The Importance and Criticality of Spreadsheets in the City of London

abstract:
  Spreadsheets have been with us in their present form for over a quarter of a
century. We have become so used to them that we forget that we are using them
at all. It may serve us well to stand back for a moment to review where, when
and how we use spreadsheets in the financial markets and elsewhere in order to
inform research that may guide their future development. In this article I
bring together the experiences of a number of senior practitioners who have
spent much of their careers working with large spreadsheets that have been and
continue to be used to support major financial transactions and manage large
institutions in the City of London. The author suggests that the City of London
is presently exposed to significant reputational risk through the continued
uncontrolled use of critical spreadsheets in the financial markets and
elsewhere.


title:
Phase transition and critical properties of spin-orbital interacting
  systems

abstract:
  Phase transition and critical properties of Ising-like spin-orbital
interacting systems in 2-dimensional triangular lattice are investigated. We
first show that the ground state of the system is a composite spin-orbital
ferro-ordered phase. Though Landau effective field theory predicts the
second-order phase transition of the composite spin-orbital order, however, the
critical exponents obtained by the renormalization group approach demonstrate
that the spin-orbital order-disorder transition is far from the second-order,
rather, it is more close to the first-order, implying that the widely observed
first-order transition in many transition-metal oxides may be intrinsic. The
unusual critical behavior near the transition point is attributed to the
fractionalization of the composite order parameter.


title:
Comment on: Increasing Exclusion: The Pauli Exclusion Principle and
  Energy Conservation for Bound Fermions are Mutually Exclusive
  arXiv:physics/0609190v4 [physics.gen-ph] by Jonathan Phillips

abstract:
  Phillips incorrectly analyzes the ionization of He to conclude that the Pauli
exclusion principle and conservation of energy are mutually exclusive. His
error arises from neglect of electron repulsion, improper choices of energy
zeros and other trivial errors.


title: A Uniform Description of the States Recently Observed at B-factories

abstract:
  The newly found states Y(4260), Y(4361), Y(4664) and Z$^\pm$(4430) stir broad
interest in the study of spectroscopy in a typical charmonium scale. The
Y(4260) which was observed earlier has been interpreted as hybrid, molecular
state, and baryonium, etc. In this note we show for the first time that these
new structures, which are hard to be interpreted as charmonium states, can be
systematically embedded into an extended baryonium picture. According to this
assignment, the so far known characters of these states are understandable.
And, in the same framework, we make some predictions for experimenters to
measure in the future.


title: Resolution of the Proton Spin Problem

abstract:
  A number of lines of investigation into the structure of the nucleon have
converged to the point where we believe that one has a consistent explanation
of the well known proton spin crisis.


title: Self-Retracting Motion of Graphite Microflakes

abstract:
  We report the observation of a novel phenomenon, the self-retracting motion
of graphite, in which tiny flakes of graphite, after being displaced to various
suspended positions from islands of highly orientated pyrolytic graphite,
retract back onto the islands under no external influences. Our repeated
probing and observing such flakes of various sizes indicate the existence of a
critical size of flakes, approximately 35 micrometer, above which the
self-retracting motion does not occur under the operation. This helps to
explain the fact that the self-retracting motion of graphite has not been
reported, because samples of natural graphite are typical larger than this
critical size. In fact, reports of this phenomenon have not been found in the
literature for single crystals of any kinds. A model that includes the static
and dynamic shear strengths, the van der Waals interaction force, and the edge
dangling bond interaction effect, was used to explain the observed phenomenon.
These findings may conduce to create nano-electromechanical systems with a wide
range of mechanical operating frequency from mega to giga hertzs.


title:
Large amounts of optically-obscured star formation in the host galaxies
  of some type-2 quasars

abstract:
  We present Hubble Space Telescope images, and spectral energy distributions
from optical to infrared wavelengths for a sample of six 0.3<z<0.8 type-2
quasars selected in the mid-infrared using data from the Spitzer Space
Telescope. All the host galaxies show some signs of disturbance. Most seem to
possess dusty, star-forming disks. The disk inclination, estimated from the
axial ratio of the hosts, correlates with the depth of the silicate feature in
the mid-infrared spectra, implying that at least some of the reddening towards
the AGN arises in the host galaxy. The star formation rates in these objects,
as inferred from the strengths of the PAH features and far-infrared continuum,
range from 3-90 Msun/yr, but are mostly much larger than those inferred from
the [OII]3727 emission line luminosity, due to obscuration. Taken together with
studies of type-2 quasar hosts from samples selected in the optical and X-ray,
this is consistent with previous suggestions that two types of extinction
processes operate within the type-2 quasar population, namely a component due
to the dusty torus in the immediate environment of the AGN, and a more extended
component due to a dusty, star forming disk.


title:
Quasi-period collapse and GL_n(Z)-scissors congruence in rational
  polytopes

abstract:
  Quasi-period collapse occurs when the Ehrhart quasi-polynomial of a rational
polytope has a quasi-period less than the denominator of that polytope. This
phenomenon is poorly understood, and all known cases in which it occurs have
been proven with ad hoc methods. In this note, we present a conjectural
explanation for quasi-period collapse in rational polytopes. We show that this
explanation applies to some previous cases appearing in the literature. We also
exhibit examples of Ehrhart polynomials of rational polytopes that are not the
Ehrhart polynomials of any integral polytope.
  Our approach depends on the invariance of the Ehrhart quasi-polynomial under
the action of affine unimodular transformations. Motivated by the similarity of
this idea to the scissors congruence problem, we explore the development of a
Dehn-like invariant for rational polytopes in the lattice setting.


title:
The singular limit of the Allen-Cahn equation and the FitzHugh-Nagumo
  system

abstract:
  We consider an Allen-Cahn type equation with a bistable nonlinearity
associated to a double-well potential whose well-depths can be slightly
unbalanced, and where the coefficient of the nonlinear reaction term is very
small. Given rather general initial data, we perform a rigorous analysis of
both the generation and the motion of interface. More precisely we show that
the solution develops a steep transition layer within a small time, and we
present an optimal estimate for its width. We then consider a class of
reaction-diffusion systems which includes the FitzHugh-Nagumo system as a
special case. Given rather general initial data, we show that the first
component of the solution vector develops a steep transition layer and that all
the results mentioned above remain true for this component.


title: Stability of foliations induced by rational maps

abstract:
  We show that the singular holomorphic foliations induced by dominant
quasi-homogeneous rational maps fill out irreducible components of the space
$\mathscr F_q(r, d)$ of singular foliations of codimension $q$ and degree $d$
on the complex projective space $\mathbb P^r$, when $1\le q \le r-2$. We study
the geometry of these irreducible components. In particular we prove that they
are all rational varieties and we compute their projective degrees in several
cases.


title: Reply to 'comment on Berry phase in a composite system'

abstract:
  In this reply, we show that the adiabatic theorem would break down in the
weak coupling limit, and the definition for the subsystem geometric phase is
well defined.


title: Comment on "Hawking Radiation and Covariant Anomalies"

abstract:
  We comment on the consistence of the epsilon anti-symmetric tensor adopted in
[R. Banerjee and S. Kulkarni, arXiv:0707.2449] when it is generalized in the
general case where $\sqrt{-g} \neq 1$. It is pointed out that the correct
non-minimal consistent gauge and gravitational anomalies should by multiplied a
factor $\sqrt{-g} \neq 1$. We also sketch the generalization of their work to
the $\sqrt{-g} \neq 1$ case.


title:
Effects of Ca substitution and the pseudogap on the magnetic properties
  of Y1-xCaxBa2Cu3O7-delta

abstract:
  The effects of planar hole content, p, on the static magnetic susceptibility,
chi(T), of Y1-xCaxBa2Cu3O7-delta polycrystalline samples were investigated over
a wide range of Ca (x) and oxygen contents. Non-magnetic Ca2+, in the 3p6
state, induces a Curie-like contribution to chi(T) that increases
systematically and non-linearly with x but is almost independent of p. We argue
that this arises from statistical clusters containing two or more nearest
neighbor Ca atoms. We have again found that the pseudogap in the quasi-particle
spectral weight appears abruptly below a planar hole content p = 0.190 +/-
0.005.


title: Numerical results of two-dimensional N=(2,2) super Yang-Mills theory

abstract:
  We report the results of a numerical simulation of a lattice formulation of
the two-dimensional N=(2,2) super Yang-Mills theory proposed by Suzuki and
Taniguchi. We measure the 1-point functions and 2-point functions. The scenario
is that only tuning of the scalar mass to a specific value gives a
supersymmetric continuum limit. Our results are consistent with this scenario
although conclusive results on the restoration of supersymmetry have not been
obtained.


title: Local Floer Homology and the Action Gap

abstract:
  In this paper, we study the behavior of the local Floer homology of an
isolated fixed point and the growth of the action gap under iterations. To be
more specific, we prove that an isolated fixed point of a Hamiltonian
diffeomorphism remains isolated for a certain class of iterations (the
so-called admissible iterations) and that the local Floer homology groups for
all such iterations are isomorphic to each other up to a shift of degree.
Furthermore, we study the pair-of-pants product in local Floer homology, and
characterize a particular class of isolated fixed points (the symplectically
degenerate maxima), which plays an important role in the proof of the Conley
conjecture. The proofs of these facts rely on an observation that for a general
diffeomorphism, not necessarily Hamiltonian, an isolated fixed point remains
isolated under all admissible iterations. Finally, we apply these results to
show that for a quasi-arithmetic sequence of admissible iterations of a
Hamiltonian diffeomorphism with isolated fixed points the minimal action gap is
bounded from above when the ambient manifold is closed and symplectically
aspherical. This theorem is a generalization of the Conley conjecture.


title: Homological flat dimensions

abstract:
  For finitely generated module $M$ over a local ring $R$, the conventional
notions of complete intersection dimension $\cid_R M$ and Cohen-Macaulay
dimension $\cmdim_R M$ do not extend to cover the case of infinitely generated
modules. In this paper we introduce similar invariants for not necessarily
finitely generated modules, (namely, complete intersection flat and
Cohen-Macaulay flat dimensions) which for finitely generated modules, coincide
with the corresponding classical ones.


title: Inferring Diversity: Life After Shannon

abstract:
  The diversity of a community that cannot be fully counted must be inferred.
The two preeminent inference methods are the MaxEnt method, which uses
information in the form of constraints and Bayes' rule which uses information
in the form of data. It has been shown that these two methods are special cases
of the method of Maximum (relative) Entropy (ME). We demonstrate how this
method can be used as a measure of diversity that not only reproduces the
features of Shannon's index but exceeds them by allowing more types of
information to be included in the inference. A specific example is solved in
detail. Additionally, the entropy that is found is the same form as the
thermodynamic entropy.


title:
Theoretical Spectra and Light Curves of Close-in Extrasolar Giant
  Planets and Comparison with Data

abstract:
  We present theoretical atmosphere, spectral, and light-curve models for
extrasolar giant planets (EGPs) undergoing strong irradiation for which {\it
Spitzer} planet/star contrast ratios or light curves have been published (circa
June 2007). These include HD 209458b, HD 189733b, TrES-1, HD 149026b, HD
179949b, and $\upsilon$ And b. By comparing models with data, we find that a
number of EGP atmospheres experience thermal inversions and have stratospheres.
This is particularly true for HD 209458b, HD 149026b, and $\upsilon$ And b.
This finding translates into qualitative changes in the planet/star contrast
ratios at secondary eclipse and in close-in EGP orbital light curves. Moreover,
the presence of atmospheric water in abundance is fully consistent with all the
{\it Spitzer} data for the measured planets. For planets with stratospheres,
water absorption features invert into emission features and mid-infrared fluxes
can be enhanced by a factor of two. In addition, the character of near-infrared
planetary spectra can be radically altered. We derive a correlation between the
importance of such stratospheres and the stellar flux on the planet, suggesting
that close-in EGPs bifurcate into two groups: those with and without
stratospheres. From the finding that TrES-1 shows no signs of a stratosphere,
while HD 209458b does, we estimate the magnitude of this stellar flux
breakpoint. We find that the heat redistribution parameter, P$_n$, for the
family of close-in EGPs assumes values from $\sim$0.1 to $\sim$0.4. This paper
provides a broad theoretical context for the future direct characterization of
EGPs in tight orbits around their illuminating stars.


title:
Non-rotating and rotating neutron stars in the extended field
  theoretical model

abstract:
  We study the properties of non-rotating and rotating neutron stars for a new
set of equations of state (EOSs) with different high density behaviour obtained
using the extended field theoretical model. The high density behaviour for
these EOSs are varied by varying the $\omega-$meson self-coupling and
hyperon-meson couplings in such a way that the quality of fit to the bulk
nuclear observables, nuclear matter incompressibility coefficient and
hyperon-nucleon potential depths remain practically unaffected. We find that
the largest value for maximum mass for the non-rotating neutron star is
$2.1M_\odot$. The radius for the neutron star with canonical mass is $12.8 -
14.1$ km provided only those EOSs are considered for which maximum mass is
larger than $1.6M_\odot$ as it is the lower bound on the maximum mass measured
so far. Our results for the very recently discovered fastest rotating neutron
star indicate that this star is supra massive with mass $1.7 - 2.7M_\odot$ and
circumferential equatorial radius $12 - 19$ km.


title: New approximate radial wave functions for power-law potentials

abstract:
  Radial wave functions for power-law potentials are approximated with the help
of power-law substitution and explicit summation of the leading constituent WKB
series. Our approach reproduces the correct behavior of the wave functions at
the origin, at the turning points and far away from the turning points


title: Molecular fluorine chemistry in the early Universe

abstract:
  Some models of Big Bang nucleosynthesis suggest that very high baryon density
regions were formed in the early Universe, and generated the production of
heavy elements other than lithium such as fluorine F. We present a
comprehensive chemistry of fluorine in the post-recombination epoch.
Calculation of F, F- and HF abundances, as a function of redshift z, are
carried out. The main result is that the chemical conditions in the early
Universe can lead to the formation of HF. The final abundance of the diatomic
molecule HF is predicted to be close to 3.75 10(-17) when the initial abundance
of neutral fluorine F is 10(-15). These results indicate that molecules of
fluorine HF were already present during the dark age. This could have
implications on the evolution of proto-objects and on the anisotropies of
cosmic microwave background radiation. Hydride of fluorine HF may affect
enhancement of the emission line intensity from the proto-objects and could
produce spectral-spatial fluctuations.


title: Upper bounds of Hilbert coefficients and Hilbert functions

abstract:
  Let $(R, m)$ be a $d$-dimensional Cohen-Macaulay local ring.
  In this note we prove, in a very elementary way, an upper bound of the first
normalized Hilbert coefficient of a $m$-primary ideal $I\subset R$ that
improves all known upper bounds unless for a finite number of cases. We also
provide new upper bounds of the Hilbert functions of $I$ extending the known
bounds for the maximal ideal.


title: Localization-delocalization transition in 2D quantum percolation model

abstract:
  We study the hopping transport of a quantum particle through randomly diluted
percolation clusters in two dimensions realized both on the square and
triangular lattices. We investigate the nature of localization of the particle
by calculating the transmission coefficient as a function of energy (-2 < E < 2
in units of the hopping integral in the tight-binding Hamiltonian) and
disorder, q (probability that a given site of the lattice is not available to
the particle). Our study based on finite size scaling suggests the existence of
delocalized states that depends on energy and amount of disorder present in the
system. For energies away from the band center (E = 0), delocalized states
appear only at low disorder (q < 15%). The transmission near the band center is
generally very small for any amount of disorder and therefore makes it
difficult to locate the transition to delocalized states if any, but our study
does indicate a behavior that is weaker than power-law localization. Apart from
this localization-delocalization transition, we also find the existence of two
different kinds of localization regimes depending on energy and amount of
disorder. For a given energy, states are exponentially localized for
sufficiently high disorder. As the disorder decreases, states first show
power-law localization before showing a delocalized behavior.


title: An Extension of Mok's Theorem on the Generalized Frankel Conjecture

abstract:
  In this paper, we will give an extension of Mok's theorem on the generalized
Frankel conjecture under the condition of the orthogonal bisectional curvature.


title: The Topology of Bendless Three-Dimensional Orthogonal Graph Drawing

abstract:
  We consider embeddings of 3-regular graphs into 3-dimensional Cartesian
coordinates, in such a way that two vertices are adjacent if and only if two of
their three coordinates are equal (that is, if they lie on an axis-parallel
line) and such that no three points lie on the same axis-parallel line; we call
a graph with such an embedding an xyz graph}. We describe a correspondence
between xyz graphs and face-colored embeddings of the graph onto
two-dimensional manifolds, and we relate bipartiteness of the xyz graph to
orientability of the underlying topological surface. Using this correspondence,
we show that planar graphs are xyz graphs if and only if they are bipartite,
cubic, and three-connected, and that it is NP-complete to determine whether an
arbitrary graph is an xyz graph. We also describe an algorithm with running
time O(n 2^{n/2}) for testing whether a given graph is an xyz graph.


title:
In Situ Experiment and Modelling of RC-Structure Using Ambient Vibration
  and Timoshenko Beam

abstract:
  Recently, several experiments were reported using ambient vibration surveys
in buildings to estimate the modal parameters of buildings. Their modal
properties are full of relevant information concerning its dynamic behaviour in
its elastic domain. The main scope of this paper is to determine relevant,
though simple, beam modelling whose validity could be easily checked with
experimental data. In this study, we recorded ambient vibrations in 3 buildings
in Grenoble selected because of their vertical structural homogeneity. First, a
set of recordings was done using a 18 channels digital acquisition system
(CityShark) connected to six 3C Lennartz 5s sensors. We used the Frequency
Domain Decomposition (FDD) technique to extract the modal parameters of these
buildings. Second, it is shown in the following that the experimental
quasi-elastic behaviour of such structure can be reduced to the behaviour of a
vertical continuous Timoshenko beam. A parametric study of this beam shows that
a bijective relation exists between the beam parameters and its
eigenfrequencies distribution. Consequently, the Timoshenko beam parameters can
be estimated from the experimental sequence of eigenfrequencies. Having the
beam parameters calibrated by the in situ data, the reliability of the
modelling is checked by complementary comparisons. For this purpose, the mode
shapes and eigenfrequencies of higher modes are calculated and compared to the
experimental data. A good agreement is also obtained. In addition, the beam
model integrates in a very synthetic way the essential parameters of the
dynamic behaviour.


title:
Quasi-binarity of massive stars in young dense clusters - the case of
  the ONC

abstract:
  Observations indicate that in young stellar clusters the binary fraction for
massive stars is higher than for solar mass stars. For the Orion Nebula Cluster
(ONC) there is a binary frequency of ~ 50% for solar-mass stars compared to
70-100% for the massive O- and B-stars. We explore the reasons for this
discrepancy and come up with two possible answers: a) a primordially higher
binarity of massive stars could be inherent to the star formation process or b)
the primordial binary rate might be the same for solar-mass and massive stars,
but the higher capture cross section of the massive stars possibly leads to the
formation of additional massive binaries in the early cluster development. Here
we investigate the likelihood of the latter using the ONC as an example. N-body
simulations are performed to track the capture events in an ONC-like cluster.
We find that whereas low-mass stars rarely form bound systems through capture,
the dynamics of the massive stars - especially in the first 0.5 Myrs - is
dominated by a rapid succession of ``transient binary or multiple systems''. In
observations the transient nature of these systems would not be apparent, so
that they would be rated as binaries. At 1-2 Myrs, the supposed age of the ONC,
the ``transient'' massive systems become increasingly stable, lasting on
average several 10^6 yrs. Despite the ONC being so young, the observed binary
frequency for massive stars -- unlike that of solar-mass stars -- is not
identical to the primordial binary frequency but is increased by at least
10-15% through dynamical interaction processes. This value might be increased
to at least 20-25% by taking disc effects into account. The primordial binary
frequency could well be the same for massive and solar mass stars because the
observed difference can be explained by capture processes alone.


title:
Directed flow as effect of transient matter rotation in hadron and
  nucleus collisions

abstract:
  We discuss directed flow introduced for description of nucleus collisions and
consider its possible behavior in hadronic and nuclei reactions due to rotation
of the transient matter.


title: Stellar populations in the center of barred spiral galaxies

abstract:
  We show observations obtained with the integral field spectrometer OASIS for
the central regions of a sample of barred galaxies. The high spatial resolution
of the instrument allows to distinguish various structures within these regions
as defined by stellar populations of different ages and metallicities. From
these data we obtain important clues about the star formation history. But we
advise that, in order to obtain adequately the evolutionary sequence, a
combination of chemical and synthesis models may be necessary.


title: Resolution of singularities for multi-loop integrals

abstract:
  We report on a program for the numerical evaluation of divergent multi-loop
integrals. The program is based on iterated sector decomposition. We improve
the original algorithm of Binoth and Heinrich such that the program is
guaranteed to terminate. The program can be used to compute numerically the
Laurent expansion of divergent multi-loop integrals regulated by dimensional
regularisation. The symbolic and the numerical steps of the algorithm are
combined into one program.


title: A Brief History of Economics: An Outsider's Account

abstract:
  A dangerously brief history of the developments of the main ideas in
economics, as observed by a physicist, is given. This was published in
'Econophysics of Stock and Other Markets', Eds. A. Chatterjee, B. K.
Chakrabarti, New Economic Windows Series, Springer, Milan, 2006, pp~219-224.


title:
Establishing a connection between high-power pulsars and
  very-high-energy gamma-ray sources

abstract:
  In the very-high-energy (VHE) gamma-ray wave band, pulsar wind nebulae (PWNe)
represent to date the most populous class of Galactic sources. Nevertheless,
the details of the energy conversion mechanisms in the vicinity of pulsars are
not well understood, nor is it known which pulsars are able to drive PWNe and
emit high-energy radiation. In this paper we present a systematic study of a
connection between pulsars and VHE gamma-ray sources based on a deep survey of
the inner Galactic plane conducted with the High Energy Stereoscopic System
(H.E.S.S.). We find clear evidence that pulsars with large spin-down energy
flux are associated with VHE gamma-ray sources. This implies that these pulsars
emit on the order of 1% of their spin-down energy as TeV gamma-rays.


title:
Flame-driven deflagration-to-detonation transitions in Type Ia
  supernovae?

abstract:
  Although delayed detonation models of thermonuclear explosions of white
dwarfs seem promising for reproducing Type Ia supernovae, the transition of the
flame propagation mode from subsonic deflagration to supersonic detonation
remains hypothetical. A potential instant for this transition to occur is the
onset of the distributed burning regime, i.e. the moment when turbulence first
affects the internal flame structure. Some studies of the burning microphysics
indicate that a deflagration-to-detonation transition may be possible here,
provided the turbulent intensities are strong enough. Consequently, the
magnitude of turbulent velocity fluctuations generated by the deflagration
flame is analyzed at the onset of the distributed burning regime in several
three-dimensional simulations of deflagrations in thermonuclear supernovae. It
is shown that the corresponding probability density functions fall off towards
high turbulent velocity fluctuations much more slowly than a Gaussian
distribution. Thus, values claimed to be necessary for triggering a detonation
are likely to be found in sufficiently large patches of the flame. Although the
microphysical evolution of the burning is not followed and a successful
deflagration-to-detonation transition cannot be guaranteed from simulations
presented here, the results still indicate that such events may be possible in
Type Ia supernova explosions.


title: Quantum Auctions: Facts and Myths

abstract:
  Quantum game theory, whatever opinions may be held due to its abstract
physical formalism, have already found various applications even outside the
orthodox physics domain. In this paper we introduce the concept of a quantum
auction, its advantages and drawbacks. Then we describe the models that have
already been put forward. A general model involves Wigner formalism and
infinite dimensional Hilbert spaces - we envisage that the implementation might
not be an easy task. But a restricted model advocated by the Hewlett-Packard
group seems to be much easier to implement. Simulations involving humans have
already been performed. We will focus on problems related to combinatorial
auctions and technical assumptions that are made. Quantum approach offers at
least two important developments. Powerful quantum algorithms for finding
solutions would extend the range of possible applications. Quantum strategies,
being qubits, can be teleported but are immune from cloning - therefore extreme
privacy of agent's activity could in principle be guaranteed. Then we point out
some key problem that have to be solved before commercial use would be
possible. With present technology, optical networks, single photon sources and
detectors seems to be sufficient for experimental realization in the near
future. We conclude by describing potential customers, estimating the potential
market size and possible timing.


title: Current to frequency conversion in a Josephson circuit

abstract:
  The voltage oscillations which occur in an ideally current-biased Josephson
junction, were proposed to make a current standard for metrology. We
demonstrate similar oscillations in a more complex Josephson circuit derived
from the Cooper pair box: the quantronium. When a constant current I is
injected in the gate capacitor of this device, oscillations develop at the
frequency fB=I/2e, with e the electron charge. We detect these oscillations
through the sidebands induced at multiples of fB in the spectrum of a microwave
signal reflected on the circuit, up to currents I exceeding 100 pA. We discuss
the potential interest of this current to frequency conversion experiment for
metrology.


title:
Hinode Calibration for Precise Image Co-alignment between SOT and XRT
  (November 2006 -- April 2007)

abstract:
  To understand the physical mechanisms for activity and heating in the solar
atmosphere, the magnetic coupling from the photosphere to the corona is an
important piece of information from the Hinode observations, and therefore
precise positional alignment is required among the data acquired by different
telescopes. The Hinode spacecraft and its onboard telescopes were developed to
allow us to investigate magnetic coupling with co-alignment accuracy better
than 1 arcsec. Using the Mercury transit observed on 8 November 2006 and
co-alignment measurements regularly performed on a weekly basis, we have
determined the information necessary for precise image co-alignment and have
confirmed that co-alignment better than 1 arcsec can be realized between Solar
Optical Telescope (SOT) and X-Ray Telescope (XRT) with our baseline
co-alignment method. This paper presents results from the calibration for
precise co-alignment of CCD images from SOT and XRT.


title: Simple derivation of the first cumulant for the Rouse chain

abstract:
  A simple analytic expression for the first cumulant of the dynamic structure
factor of a polymer coil in the Rouse model is derived. The obtained formula is
exact within the usual assumption of the continuum distribution of beads along
the chain. It reflects the contributions to the scattering of light or neutrons
from both the internal motion of the polymer and its diffusion, and is valid in
the whole region of the wave-vector change at the scattering.


title: How certain is the distance to the most luminous supernova?

abstract:
  A recent supernova has been reported as exceeding ``the light output of an
ordinary supernova by at least two orders of magnitude''. It is noted that it
falls in a minor galaxy in the Perseus Cluster. Some evidence indicating a ten
times closer distance for the Perseus Cluster than its redshift distance is
discussed here.


title: Is the physical vacuum a preferred frame ?

abstract:
  It is generally assumed that the physical vacuum of particle physics should
be characterized by an energy momentum tensor in such a way to preserve exact
Lorentz invariance. On the other hand, if the ground state were characterized
by its energy-momentum vector, with zero spatial momentum and a non-zero
energy, the vacuum would represent a preferred frame. Since both theoretical
approaches have their own good motivations, we propose an experimental test to
decide between the two scenarios.


title: The Infinite in Sciences and Arts

abstract: Actual infinity in its various forms is discussed, searched and not found.


title: H.E.S.S. observations of the supernova remnant RCW 86

abstract:
  The shell-type supernova remnant (SNR) RCW 86 - possibly associated with the
historical supernova SN 185 - was observed during the past three years with the
High Energy Stereoscopic System (H.E.S.S.), an array of four
atmospheric-Cherenkov telescopes located in Namibia. The multi-wavelength
properties of RCW 86, e.g. weak radio emission and North-East X-ray emission
almost entirely consisting of synchroton radiation, resemble those of two
very-high energy (VHE; > 100 GeV) gamma-ray emitting SNRs RX J1713.7-3946 and
RX J0852-4622. The H.E.S.S. observations reveal a new extended source of VHE
gamma-ray emission.The morphological and spectral properties of this new source
will be presented.


title:
Effects of hydrodynamic noise on the diffusion of polymers in dilute
  solutions

abstract:
  The Rouse-Zimm equation for the position vectors of beads mapping the polymer
is generalized by taking into account the viscous aftereffect and the
hydrodynamic noise. For the noise, the random fluctuations of the hydrodynamic
tensor of stresses are responsible. The preaveraging of the Oseen tensor for
the nonstationary Navier-Stokes equation allowed us to relate the time
correlation functions of the Fourier components of the bead position to the
correlation functions of the hydrodynamic field created by the noise. The
velocity autocorrelation function of the center of inertia of the polymer coil
is considered in detail for both the short and long times when it behaves
according to the t^(-3/2) law and does not depend on any polymer parameters.
The diffusion coefficient of the polymer is close to that from the Zimm theory,
with corrections depending on the ratio between the size of the bead and the
size of the whole coil.


title:
Instabilities, nonhermiticity and exceptional points in the cranking
  model

abstract:
  A cranking harmonic oscillator model, widely used for the physics of fast
rotating nuclei and Bose-Einstein condensates, is re-investigated in the
context of PT-symmetry. The instability points of the model are identified as
exceptional points. It is argued that - even though the Hamiltonian appears
hermitian at first glance - it actually is not hermitian within the region of
instability.


title: Capacitary estimates of solutions of semilinear parabolic equations

abstract:
  We prove an almoste representation formula for positive solutions of
semilinear heat equations with power-type absorption the initial trace of which
is the indicatrix function of a compact set. The representations involves a
Wiener test via Bessel capacities.


title: Factorization of Laurent series over commutative rings

abstract:
  We generalize the Wiener-Hopf factorization of Laurent series to more general
commutative coefficient rings, and we give explicit formulas for the
decomposition. We emphasize the algebraic nature of this factorization.


title:
Metal-insulator transition in half-filling two-orbital Hubbard model on
  triangular lattice

abstract:
  We have investigated the half-filling two-orbital Hubbard model on a
triangular lattice by means of the dynamical mean-field theory (DMFT). The
densities of states and optical conductivity clearly show the occurence of
metal-insulating transition (MIT) at U$_{c}$, U$_{c}$=18.2, 16.8, 6.12 and 5.85
for J=0, 0.01U, U/4 and U/3, respectively. The distinct continuities of double
occupation of electrons, local square moments and local susceptibility of the
charge, the spin and the orbital at J > 0 suggest that the MIT is the
first-order; however at J=0, the MIT is the second-order in the half-filling
two-orbital Hubbard model on triangular lattices. We attribute the first-order
nature of the MIT to the low symmetry of the systems with finite Hund's
coupling J.


title:
Enhanced Deflection of Light Ray by Atomic Ensemble on Coherent
  Population Oscillation

abstract:
  In recent experiments[e.g., Nature Physics 2, 332 (2006)], the enhanced light
deflection in an atomic ensemble due to inhomogeneous fields is demonstrated by
the electromagnetically induced transparency (EIT) based mechanism. In this
paper, we explore an different mechanism for the similar phenomenon of the
enhanced light deflection. This mechanism is based on the coherent population
oscillation, which leads to the hole burning in the absorption spectrum. The
medium causing the deflection of probe light is an ensemble of two-level atoms
manipulated by a strong controlled field on the two photon resonances. In the
large detuning condition, the response of the medium to the pump field and
signal field is obtained with steady state approximation. And it is found that
after the probe field travels across the medium, the signal ray bends due to
the spatial-dependent profile of the control beam.


title: Logarithmic link smearing for full QCD

abstract:
  A Lie-algebra based recipe for smoothing gauge links in lattice field theory
is presented, building on the matrix logarithm. With or without hypercubic
nesting, this LOG/HYL smearing yields fat links which are differentiable w.r.t.
the original ones. This is essential for defining UV-filtered ("fat link")
fermion actions which may be simulated with a HMC-type algorithm. The effect of
this smearing on the distribution of plaquettes and on the residual mass of
tree-level O(a)-improved clover fermions in quenched QCD is studied.


title: h/e-Periodicity in Superconducting Loops

abstract:
  The magnetic flux periodicity of superconducting loops as well as flux
quantization itself are a manifestation of macroscopic quantum phenomena with
far reaching implications. They provide the key to the understanding of many
fundamental properties of superconductors and are the basis for most bulk and
device applications of these materials. In superconducting rings the electrical
current has been known to periodically respond to a magnetic flux with a
periodicity of $\bm{h/2e}$. Here, the ratio of Planck's constant and the
elementary charge defines the magnetic flux quantum $\bm{h/e}$. The well-known
$\bm{h/2e}$ periodicity is viewed to be a hallmark for electronic pairing in
superconductors and is considered evidence for the existence of Cooper pairs.
Here we show that in contrast to this long-term belief, rings of many
superconductor bear an $\bm{h/e}$ periodicity. These superconductors include
the high-$\bm{T_c}$ cuprates, Sr$_2$RuO$_4$, the heavy-fermion superconductors,
as well as all other unconventional superconductors with nodes in the energy
gap functions, and s-wave superconductors with small gaps or states in the gap.
As we show, the 50-year-old Bardeen--Cooper--Schrieffer theory of
superconductivity implies that for multiply connected paths of such
superconductors the ground-state energies and consequently also the
supercurrents are generically $\bm{h/e}$ periodic. The origin of this
periodicity is a magnetic-field driven reconstruction of the condensate and a
concomitant Doppler-shifted energy spectrum. The robust, flux induced
reconstruction of the condensate will be an important aspect to understand the
magnetic properties of mesoscopic unconventional superconductors.


title: Cyclotomy Primality Proofs and their Certificates

abstract:
  The first efficient general primality proving method was proposed in the year
1980 by Adleman, Pomerance and Rumely and it used Jacobi sums. The method was
further developed by H. W. Lenstra Jr. and more of his students and the
resulting primality proving algorithms are often referred to under the generic
name of Cyclotomy Primality Proving (CPP). In the present paper we give an
overview of the theoretical background and implementation specifics of CPP,
such as we understand them in the year 2007.


title: Dual Elliptic Primes and Applications to Cyclotomy Primality Proving

abstract:
  Two rational primes p, q are called dual elliptic if there is an elliptic
curve E mod p with q points. They were introduced as an interesting means for
combining the strengths of the elliptic curve and cyclotomy primality proving
algorithms. By extending to elliptic curves some notions of galois theory of
rings used in the cyclotomy primality tests, one obtains a new algorithm which
has heuristic cubic run time and generates certificates that can be verified in
quadratic time.
  After the break through of Agrawal, Kayal and Saxena has settled the
complexity theoretical problem of primality testing, some interest remains for
the practical aspect of state of the art implementable proving algorithms.