title:
Rectified dc voltage versus magnetic field in a superconducting
  asymmetric figure-of-eight-shaped microstructure

abstract:
  We have measured periodic oscillations of rectified dc voltage versus
magnetic field V_{dc}(B) in a superconducting aluminum thin-film
circular-asymmetric figure-of-eight microstructure threaded by a magnetic flux
and biased with a sinusoidal alternating current (without a dc component) near
the critical temperature. The Fourier spectra of these V_{dc}(B) functions
contain fundamental frequencies representing periodic responses of the larger
and smaller asymmetric circular loops, composing the microstructure, to the
magnetic field. The higher harmonics of the obtained fundamental frequencies
result from the non-sinusoidal character of loop circulating currents. The
presence of the difference and summation frequencies in these spectra points to
the interaction between the quantum states of both loops. Magnitudes of the
loop responses to the bias ac and magnetic field vary with temperature and the
bias current amplitude, both in absolute values and with respect to each other.
The strongest loop response appears when the average resistive state of the
loop corresponds to the midpoint of the superconducting-normal phase
transition.


title:
Affine Demazure modules and $T$-fixed point subschemes in the affine
  Grassmannian

abstract:
  Let $G$ be a simple algebraic group of type $A$ or $D$ defined over $\C$ and
$T$ be a maximal torus of $G$. For a dominant coweight $\lambda$ of $G$, the
$T$-fixed point subscheme $(\bar{Gr}_G^\lambda)^T$ of the Schubert variety
$\bar{Gr}_G^\lambda$ in the affine Grassmannian $Gr_G$ is a finite scheme. We
prove that there is a natural isomorphism between the dual of the level one
affine Demazure module corresponding to $\lambda$ and the ring of functions
(twisted by certain line bundle on $Gr_G$) of $(\bar{Gr}_G^\lambda)^T$. We use
this fact to give a geometric proof of the Frenkel-Kac-Segal isomorphism
between basic representations of affine algebras of $A,D,E$ type and lattice
vertex algebras.


title: On the size of the Fe II emitting region in the AGN Akn 120

abstract:
  We present a reverberation analysis of the strong, variable optical Fe II
emission bands in the spectrum of Akn 120, a low-redshift AGN which is one of
the best candidates for such a study. On time scales of several years the Fe II
line strengths follow the variations in the continuum strength. However, we are
unable to measure a clear reverberation lag time for these Fe II lines on any
time scale. This is due to the very broad and flat-topped nature of the Fe II
cross correlation functions, as compared to the H-beta response which is much
more sharply localized in time. Although there is some suggestion in the light
curve of a 300-day response time, our statistical analysis does not pick up
such a feature. We conclude that the optical Fe II emission does not come from
a photoionization-powered region similar in size to the H-beta emitting region,
but we cannot say for sure where it does come from. Our results are generally
consistent either with emission from a photoionized region several times larger
than the H-beta zone, or with emission from gas heated by some other means,
perhaps responding only indirectly to the continuum variations.


title: Lateral Casimir-Polder force with corrugated surfaces

abstract:
  We derive the lateral Casimir-Polder force on a ground state atom on top of a
corrugated surface, up to first order in the corrugation amplitude. Our
calculation is based on the scattering approach, which takes into account
nonspecular reflections and polarization mixing for electromagnetic quantum
fluctuations impinging on real materials. We compare our first order exact
result with two commonly used approximation methods. We show that the proximity
force approximation (large corrugation wavelengths) overestimates the lateral
force, while the pairwise summation approach underestimates it due to the
non-additivity of dispersion forces. We argue that a frequency shift
measurement for the dipolar lateral oscillations of cold atoms could provide a
striking demonstration of nontrivial geometrical effects on the quantum vacuum.


title:
Time-frequency analysis of extreme-mass-ratio inspiral signals in mock
  LISA data

abstract:
  Extreme-mass-ratio inspirals (EMRIs) of ~ 1-10 solar-mass compact objects
into ~ million solar-mass massive black holes can serve as excellent probes of
strong-field general relativity. The Laser Interferometer Space Antenna (LISA)
is expected to detect gravitational wave signals from apprxomiately one hundred
EMRIs per year, but the data analysis of EMRI signals poses a unique set of
challenges due to their long duration and the extensive parameter space of
possible signals. One possible approach is to carry out a search for EMRI
tracks in the time-frequency domain. We have applied a time-frequency search to
the data from the Mock LISA Data Challenge (MLDC) with promising results. Our
analysis used the Hierarchical Algorithm for Clusters and Ridges to identify
tracks in the time-frequency spectrogram corresponding to EMRI sources. We then
estimated the EMRI source parameters from these tracks. In these proceedings,
we discuss the results of this analysis of the MLDC round 1.3 data.


title: Positivity of Thom polynomials II: the Lagrange singularities

abstract:
  We show that Thom polynomials of Lagrangian singularities have nonnegative
coefficients in the basis consisting of Q-functions. The main tool in the proof
is nonnegativity of cone classes for globally generated bundles.


title: Cycle-free chessboard complexes and symmetric homology of algebras

abstract:
  Chessboard complexes and their relatives have been one of important recurring
themes of topological combinatorics. Closely related ``cycle-free chessboard
complexes'' have been recently introduced by Ault and Fiedorowicz as a tool for
computing symmetric analogues of the cyclic homology of algebras. We study
connectivity properties of these complexes and prove a result that confirms a
strengthened conjecture of Ault and Fiedorowicz.


title: Structure of Supergiant Shells in the Large Magellanic Cloud

abstract:
  Nine supergiant shells (SGSs) have been identified in the Large Magellanic
Cloud (LMC) based on H-alpha images, and twenty-three SGSs have been reported
based on HI 21-cm line observations, but these sets do not always identify the
same structures. We have examined the physical structure of the optically
identified SGSs using HI channel maps and P-V diagrams to analyze the gas
kinematics. There is good evidence for seven of the nine optically identified
SGSs to be true shells. Of these seven H-alpha SGSs, four are the ionized inner
walls of HI SGSs, while three are an ionized portion of a larger and more
complex HI structure. All of the H-alpha SGSs are identified as such because
they have OB associations along the periphery or in the center, with younger OB
associations more often found along the periphery. After roughly 12 Myrs, if no
new OB associations have been formed a SGS will cease to be identifiable at
visible wavelengths. Thus, the presence and location of ionizing sources is the
main distinction between shells seen only in HI and those also seen in H-alpha.
Based on our analysis, H-alpha observations alone cannot unambiguously identify
SGSs, especially in distant galaxies.


title: Motivic L-Functions

abstract:
  This is the text of an introductory lecture delivered at the IHES summer
school on motives in July, 2006.


title: Diophantine Geometry as Galois Theory in the Mathematics of Serge Lang

abstract:
  A remark about the role of Galois theory in Diophantine geometry as reflected
in the work of Serge Lang. An entry in `The mathematical contributions of Serge
Lang.'


title:
Propagation of $L^{1}$ and $L^{\infty}$ Maxwellian weighted bounds for
  derivatives of solutions to the homogeneous elastic Boltzmann Equation

abstract:
  We consider the $n$-dimensional space homogeneous Boltzmann equation for
elastic collisions for variable hard potentials with Grad (angular) cutoff. We
prove sharp moment inequalities, the propagation of $L^1$-Maxwellian weighted
estimates, and consequently, the propagation $L^\infty$-Maxwellian weighted
estimates to all derivatives of the initial value problem associated to the
afore mentioned problem.
  More specifically, we extend to all derivatives of the initial value problem
associated to this class of Boltzmann equations corresponding sharp moment
(Povzner) inequalities and time propagation of $L^1$-Maxwellian weighted
estimates as originally developed A.V. Bobylev in the case of hard spheres in 3
dimensions; an improved sharp moments inequalities to a larger class of angular
cross sections and $L^1$-exponential bounds in the case of stationary states to
Boltzmann equations for inelastic interaction problems with `heating' sources,
by A.V. Bobylev, I.M. Gamba and V.Panferov, where high energy tail decay rates
depend on the inelasticity coefficient and the the type of `heating' source;
and more recently, extended to variable hard potentials with angular cutoff by
I.M. Gamba, V. Panferov and C. Villani in the elastic case collision case and
so $L^1$-Maxwellian weighted estimated were shown to propagate if initial
states have such property. In addition, we also extend to all derivatives the
propagation of $L^\infty$-Maxwellian weighted estimates to solutions of the
initial value problem to the Boltzmann equations for elastic collisions for
variable hard potentials with Grad (angular) cutoff.


title: Eigenvectors in the Superintegrable Model I: sl_2 Generators

abstract:
  In order to calculate correlation functions of the chiral Potts model, one
only needs to study the eigenvectors of the superintegrable model. Here we
start this study by looking for eigenvectors of the transfer matrix of the
periodic tau_2(t)model which commutes with the chiral Potts transfer matrix. We
show that the degeneracy of the eigenspace of tau_2(t) in the Q=0 sector is
2^r, with r=(N-1)L/N when the size of the transfer matrix L is a multiple of N.
We introduce chiral Potts model operators, different from the more commonly
used generators of quantum group U-tilde_q(sl-hat(2)). From these we can form
the generators of a loop algebra L(sl(2)). For this algebra, we then use the
roots of the Drinfeld polynomial to give new explicit expressions for the
generators representing the loop algebra as the direct sum of r copies of the
simple algebra sl(2).


title: Electronic structure of kinetic energy driven cuprate superconductors

abstract:
  In this paper, we review the low energy electronic structure of the kinetic
energy driven d-wave cuprate superconductors. We give a general description of
the charge-spin separation fermion-spin theory, where the constrained electron
is decoupled as the gauge invariant dressed holon and spin. In particular, we
show that under the decoupling scheme, the charge-spin separation fermion-spin
representation is a natural representation of the constrained electron defined
in a restricted Hilbert space without double electron occupancy. Based on the
charge-spin separation fermion-spin theory, we have developed the kinetic
energy driven superconducting mechanism, where the superconducting state is
controlled by both superconducting gap parameter and quasiparticle coherence.
Within this kinetic energy driven superconductivity, we have discussed the low
energy electronic structure of the single layer and bilayer cuprate
superconductors in both superconducting and normal states, and qualitatively
reproduced all main features of the angle-resolved photoemission spectroscopy
measurements on the single layer and bilayer cuprate superconductors. We show
that the superconducting state in cuprate superconductors is the conventional
Bardeen-Cooper-Schrieffer like with the d-wave symmetry, so that the basic
Bardeen-Cooper-Schrieffer formalism with the d-wave gap function is still valid
in discussions of the low energy electronic structure of cuprate
superconductors, although the pairing mechanism is driven by the kinetic energy
by exchanging spin excitations. We also show that the well pronounced
peak-dip-hump structure of the bilayer cuprate superconductors in the
superconducting state and double-peak structure in the normal state are mainly
caused by the bilayer splitting.


title:
High sensitivity cantilevers for measuring persistent currents in normal
  metal rings

abstract:
  We propose a new approach to measuring persistent currents in normal metal
rings. By integrating micron-scale metal rings into sensitive micromechanical
cantilevers and using the cantilevers as torque magnetometers, it should be
possible to measure the rings' persistent currents with greater sensitivity
than the SQUID-based and microwave resonator-based detectors used in the past.
In addition, cantilever-based detectors may allow for measurements in a cleaner
electromagnetic environment. We have fabricated ultra sensitive cantilevers
with integrated rings and measured their mechanical properties. We present an
estimate of the persistent current sensitivity of these cantilever-based
detectors, focusing on the limits set by the cantilever's Brownian motion and
the shot noise in the laser interferometer that monitors the cantilever.


title:
On the nature of steady states of spin distributions in the presence of
  spin-orbit interactions

abstract:
  In the presence of spin-orbit interactions, the steady state established for
spin distributions in an electric field is qualitatively different from the
steady state for charge distributions. This is primarily because the steady
state established for spin distributions involves spin precession due to
spin-orbit coupling. We demonstrate in this work that the spin density matrix
in an external electric field acquires two corrections with different
dependencies on the characteristic momentum scattering time. One part is
associated with conserved spins, diverges in the clean limit and is responsible
for the establishment of a steady-state spin density in electric fields.
Another part is associated with precessing spins, is finite in the clean limit
and is responsible for the establishment of spin currents in electric fields.
Scattering between these distributions has important consequences for spin
dynamics and spin-related effects in general, and explains some recent puzzling
observations, which are captured by our unified theory.


title:
Filamentation Instability of Interacting Current Sheets in Striped
  Relativistic Winds: The Origin of Low Sigma?

abstract:
  I outline a mechanism, akin to Weibel instabilities of interpenetrating
beams, in which the neighboring current sheets in a striped wind from an
oblique rotator interact through a two stream-like mechanism (a Weibel
instability in flatland), to create an anomalous resistivity that heats the
sheets and causes the magnetic field to diffusively annihilate in the wind
upstream of the termination shock. The heating has consequences for observable
unpulsed emission from pulsars.


title: Pulsar Dreams

abstract: I share a few reminiscences and observations of 40 years of Pulsars.


title: Geometry of Character Varieties of Surface Groups

abstract:
  This article is based on a talk delivered at the RIMS--OCAMI Joint
International Conference on Geometry Related to Integrable Systems in
September, 2007. Its aim is to review a recent progress in the Hitchin
integrable systems and character varieties of the fundamental groups of Riemann
surfaces. A survey on geometric aspects of these character varieties is also
provided as we develop the exposition from a simple case to more elaborate
cases.


title: Aging in a Colloidal Glass in Creep Flow: Time-Stress Superposition

abstract:
  In this work, we study ageing behavior of aqueous laponite suspension, a
model soft glassy material, in creep. We observe that viscoelastic behavior is
time dependent and is strongly influenced by the deformation field; the effect
is known to arise due to ageing and rejuvenation. We show that irrespective of
strength of deformation field (shear stress) and age, when imposed time-scale
is normalized with dominating relaxation mode of the system, universal ageing
behavior is obtained demonstrating time-stress superposition; the phenomena
that may be generic in variety of soft materials.


title: Goldman flows on a nonorientable surface

abstract:
  Given an embedded cylinder in an arbitrary surface, we give a gauge theoretic
definition of the associated Goldman flow, which is a circle action on a dense
open subset of the moduli space of equivalence classes of flat
SU(2)-connections over the surface. A cylinder in a compact nonorientable
surface lifts to two cylinders in the orientable double cover, and the
"composite flow" is the composition of one of the associated flows with the
inverse flow of the other. Providing explicit descriptions, we relate the flow
on the moduli space of the nonorientable surface with the composite flow on the
moduli space of the double cover. We prove that the composite flow preserves a
certain Lagrangian submanifold.


title:
Energy loss and damage production by heavy ions and strange quark matter
  in silicon

abstract:
  In this contribution, the peculiarities of the behaviour of strange quark
matter in respect to ordinary ions in silicon are investigated, and a tentative
to identify possible observable effects of degradation is made.


title: Fermion excitations of a tense brane black hole

abstract:
  By finding the spinor eigenvalues for a single deficit angle (d-2)-sphere, we
derive the radial potential for fermions on a d-dimensional black hole
background that is embedded on a codimension two brane with conical
singularity, where the deficit angle is related to the brane tension. From this
we obtain the quasi-normal mode spectrum for bulk fermions on such a
background. As a byproduct of our method, this also gives a rigorous proof for
integer spin fields on the deficit 2-sphere.


title: How to evaluate the calibration of a disease risk prediction tool

abstract:
  To evaluate the calibration of a disease risk prediction tool, the quantity
$E/O$, i.e., the ratio of the expected number of events to the observed number
of events, is generally computed. However, because of censoring, or more
precisely because of individuals who drop out before the termination of the
study, this quantity is generally unavailable for the complete population study
and an alternative estimate has to be computed. In this paper, we present and
compare four methods to do this. We show that two of the most commonly used
methods generally lead to biased estimates. Our arguments are first based on
some theoretic considerations. Then, we perform a simulation study to highlight
the magnitude of the previously mentioned biases. As a concluding example, we
evaluate the calibration of an existing predictive model for breast cancer on
the E3N-EPIC cohort.


title: Cyclic Universes from General Collisionless Braneworld Models

abstract:
  We investigate the full 5D dynamics of general braneworld models. Without
making any further assumptions we show that cyclic behavior can arise naturally
in a fraction of physically accepted solutions. The model does not require
brane collisions, which in the stationary case remain fixed, and cyclicity
takes place on the branes. We indicate that the cosmological constants play the
central role for the realization of cyclic solutions and we show that its
extremely small value on the observable universe makes the period of the cycles
and the maximum scale factor astronomically large.


title: Markov Properties of Electrical Discharge Current Fluctuations in Plasma

abstract:
  Using the Markovian method, we study the stochastic nature of electrical
discharge current fluctuations in the Helium plasma. Sinusoidal trends are
extracted from the data set by the Fourier-Detrended Fluctuation analysis and
consequently cleaned data is retrieved. We determine the Markov time scale of
the detrended data set by using likelihood analysis. We also estimate the
Kramers-Moyal's coefficients of the discharge current fluctuations and derive
the corresponding Fokker-Planck equation. In addition, the obtained Langevin
equation enables us to reconstruct discharge time series with similar
statistical properties compared with the observed in the experiment. We also
provide an exact decomposition of temporal correlation function by using
Kramers-Moyal's coefficients. We show that for the stationary time series, the
two point temporal correlation function has an exponential decaying behavior
with a characteristic correlation time scale. Our results confirm that, there
is no definite relation between correlation and Markov time scales. However
both of them behave as monotonic increasing function of discharge current
intensity. Finally to complete our analysis, the multifractal behavior of
reconstructed time series using its Keramers-Moyal's coefficients and original
data set are investigated. Extended self similarity analysis demonstrates that
fluctuations in our experimental setup deviates from Kolmogorov (K41) theory
for fully developed turbulence regime.


title:
Highly He-Rich Matter Dredged Up by Extra Mixing through Stellar
  Encounters in Globular Clusters

abstract:
  The unveiled main-sequence splitting in omega Centauri as well as NGC 2808
suggests that matter highly-enriched in He (in terms of its mass fraction
Y~0.4) was produced and made the color of some main-sequence stars bluer in
these globular clusters (GCs). The potential production site for the He-rich
matter is generally considered to be massive AGB stars that experience the
second dredge-up. However, it is found that massive AGB stars provide the
matter with Y~0.35 at most, while the observed blue-shift requires the presence
of Y~0.4 matter. Here, we show that extra mixing, which operates in the red
giant phase of stars less massive than ~2Msun, could be a mechanism that
enhances He content in their envelopes up to Y~0.4. The extra mixing is
supposed to be induced by red giant encounters with other stars in a
collisional system like GCs. The Y~0.4 matter released in the AGB phase has
alternative fates to (i) escape from a GC or (ii) be captured by kinematically
cool stars through encounters. The AGB ejecta in omega Cen, which follows the
latter case, can supply sufficient He to cause the observed blue-shift.
Simultaneously, this scheme generates the extreme horizontal branch, as
observed in omega Cen in response to the higher mass loss rates, which is also
caused by stellar encounters.


title:
Truncated decompositions and filtering methods with
  Reflective/Anti-Reflective boundary conditions: a comparison

abstract:
  The paper analyzes and compares some spectral filtering methods as truncated
singular/eigen-value decompositions and Tikhonov/Re-blurring regularizations in
the case of the recently proposed Reflective [M.K. Ng, R.H. Chan, and W.C.
Tang, A fast algorithm for deblurring models with Neumann boundary conditions,
SIAM J. Sci. Comput., 21 (1999), no. 3, pp.851-866] and Anti-Reflective [S.
Serra Capizzano, A note on anti-reflective boundary conditions and fast
deblurring models, SIAM J. Sci. Comput., 25-3 (2003), pp. 1307-1325] boundary
conditions. We give numerical evidence to the fact that spectral decompositions
(SDs) provide a good image restoration quality and this is true in particular
for the Anti-Reflective SD, despite the loss of orthogonality in the associated
transform. The related computational cost is comparable with previously known
spectral decompositions, and results substantially lower than the singular
value decomposition. The model extension to the cross-channel blurring
phenomenon of color images is also considered and the related spectral
filtering methods are suitably adapted.


title:
The environment of the fast rotating star Achernar - High-resolution
  thermal infrared imaging with VISIR in BURST mode

abstract:
  Context: The geometry of the circumstellar envelopes (CSE) surrounding Be
stars is still uncertain, although it is often assumed that they are formed by
a disk around the stellar equator and a hot polar wind. Achernar (Alpha Eri) is
the nearest Be star, and we recently detected a CSE using near-IR
interferometry. Aims: Our initial goal was to constrain the geometry and flux
contribution of the CSE of Achernar at distances of a few tens of AU from the
star, in the thermal IR domain to complement our near-IR interferometric
observations. Methods: We obtained diffraction-limited images of Achernar in
the thermal infrared using VISIR at the VLT. In order to freeze the turbulence,
we used the BURST mode of this instrument. Results: The images obtained in the
PAH1 band show a point-like source located 0.280" north-west of Achernar
(projected linear separation of 12.3 AU). Its emission is 1.8 % of the flux of
Achernar in this band, but is not detected in the PAH2, SiC and NeII bands. We
also provide new thermal IR photometry of Achernar in four bands. Conclusions:
Being aligned with the expected azimuth of the equatorial plane of Achernar,
the detected source could be a main sequence stellar companion. In this case,
it apparent brightness would correspond to an A7V spectral type.


title: Analysis of the vertex $D^*D^* \rho$ with the light-cone QCD sum rules

abstract:
  In this article, we analyze the vertex $D^*D^*\rho$ with the light-cone QCD
sum rules. The strong coupling constant $g_{D^*D^*\rho}$ is an important
parameter in evaluating the charmonium absorption cross sections in searching
for the quark-gluon plasmas. Our numerical value for the $g_{D^*D^*\rho}$ is
consistent with the prediction of the effective SU(4) symmetry and vector meson
dominance theory.


title:
Is There a Relationship between the Density of Primordial Black Holes in
  a Galaxy and the Rate of Cosmological Gamma-Ray Bursts?

abstract:
  The rate of accretion of matter from a solar-type star onto a primordial
black hole (PBH) that passes through it is calculated. The probability that a
PBH is captured into an orbit around a star in a galaxy is found. The mean
lifetime of the PBH in such an orbit and the rate of orbital captures of PBHs
in the galaxy are calculated. It is shown that this rate does not depend on the
mass of the PBH. This mechanism cannot make an appreciable contribution to the
rate of observed gamma-ray bursts. The density of PBHs in the galaxy can reach
a critical value - the density of the mass of dark matter in the galaxy.


title: Electronegativity in quantum electronic transport

abstract:
  Electronegativity is shown to control charge transfer, energy level
alignments, and electron currents in single molecule tunnel junctions, all of
which are governed by correlations contained within the density matrix. This is
demonstrated by the fact that currents calculated from the one-electron reduced
density matrix to second order in electron correlation are identical to the
currents obtained from the Green's function corrected to second order in
electron self-energy.


title: Differential equations associated with nonarithmetic Fuchsian groups

abstract:
  We describe globally nilpotent differential operators of rank 2 defined over
a number field whose monodromy group is a nonarithmetic Fuchsian group. We show
that these differential operators have an S-integral solution. These
differential operators are naturally associated with Teichmueller curves in
genus 2. They are counterexamples to conjectures by Chudnovsky--Chudnovsky and
Dwork. We also determine the field of moduli of primitive Teichmueller curves
in genus 2, and an explicit equation in some cases.


title:
A transiting planet among 23 new near-threshold candidates from the OGLE
  survey - OGLE-TR-182

abstract:
  By re-processing the data of the second season of the OGLE survey for
planetary transits and adding new mesurements on the same fields gathered in
subsequent years with the OGLE telescope, we have identified 23 new transit
candidates, recorded as OGLE-TR-178 to OGLE-TR-200. We studied the nature of
these objects with the FLAMES/UVES multi-fiber spectrograph on the VLT. One of
the candidates, OGLE-TR-182, was confirmed as a transiting gas giant planet on
a 4-day orbit. We characterised it with further observations using the FORS1
camera and UVES spectrograph on the VLT. OGLE-TR-182b is a typical ``hot
Jupiter'' with an orbital period of 3.98 days, a mass of 1.01 +- 0.15 MJup and
a radius of 1.13 (+0.24-0.08) RJup. Confirming this transiting planet required
a large investment in telescope time with the best instruments available, and
we comment on the difficulty of the confirmation process for transiting planets
in the OGLE survey. We delienate the zone were confirmation is difficult or
impossible, and discuss the implications for the Corot space mission in its
quest for transiting telluric planets.


title:
Normal subgroups of the algebraic fundamental group of affine curves in
  positive characteristic

abstract:
  Let $\pi_1(C)$ be the algebraic fundamental group of a smooth connected
affine curve, defined over an algebraically closed field of characteristic
$p>0$ of countable cardinality. Let $N$ be a normal (resp. characteristic)
subgroup of $\pi_1(C)$. Under the hypothesis that the quotient $\pi_1(C)/N$
admits an infinitely generated Sylow $p$-subgroup, we prove that $N$ is indeed
isomorphic to a normal (resp. characteristic) subgroup of a free profinite
group of countable cardinality. As a consequence, every proper open subgroup of
$N$ is a free profinite group of countable cardinality.


title: Emergence of multiscaling in heterogeneous complex networks

abstract:
  In this paper we provide numerical evidence of the richer behavior of the
connectivity degrees in heterogeneous preferential attachment networks in
comparison to their homogeneous counterparts. We analyze the degree
distribution in the threshold model, a preferential attachment model where the
affinity between node states biases the attachment probabilities of links. We
show that the degree densities exhibit a power-law multiscaling which points to
a signature of heterogeneity in preferential attachment networks. This
translates into a power-law scaling in the degree distribution, whose exponent
depends on the specific form of heterogeneity in the attachment mechanism.


title:
An extended formalism for preferential attachment in heterogeneous
  complex networks

abstract:
  In this paper we present a framework for the extension of the preferential
attachment (PA) model to heterogeneous complex networks. We define a class of
heterogeneous PA models, where node properties are described by fixed states in
an arbitrary metric space, and introduce an affinity function that biases the
attachment probabilities of links. We perform an analytical study of the
stationary degree distributions in heterogeneous PA networks. We show that
their degree densities exhibit a richer scaling behavior than their homogeneous
counterparts, and that the power law scaling in the degree distribution is
robust in presence of heterogeneity.


title: Scalar Field Equations from Quantum Gravity during Inflation

abstract:
  We exploit a previous computation of the self-mass-squared from quantum
gravity to include quantum corrections to the scalar evolution equation. The
plane wave mode functions are shown to receive no significant one loop
corrections at late times. This result probably applies as well to the inflaton
of scalar-driven inflation. If so, there is no significant correction to the
$\phi \phi$ correlator that plays a crucial role in computations of the power
spectrum.


title:
The Static Approximation to B Meson Mixing using Light Domain-Wall
  Fermions: Perturbative Renormalization and Ground State Degeneracies

abstract:
  We discuss the theoretical input into the current RBC-UKQCD calculation of
$f_{B_{d, s}}$ and $B_{B_{d, s}}$ using a smeared static heavy quark
propagator, light domain-wall quarks and the Iwasaki gauge action. We present
the complete one-loop, mean-field improved matching of heavy-light current and
four-fermion lattice operators onto the static continuum theory renormalized in
$\bar{\text{MS}}$(NDR). The large degeneracies present in a static calculation
are addressed, and a method for extracting $f_B$ and $B_B$ using only box
sources is described; implications for future calculations are discussed.


title: Staggered grids discretization in three-dimensional Darcy convection

abstract:
  We consider three-dimensional convection of an incompressible fluid saturated
in a parallelepiped with a porous medium. A mimetic finite-difference scheme
for the Darcy convection problem in the primitive variables is developed. It
consists of staggered nonuniform grids with five types of nodes, differencing
and averaging operators on a two-nodes stencil. The nonlinear terms are
approximated using special schemes. Two problems with different boundary
conditions are considered to study scenarios of instability of the state of
rest. Branching off of a continuous family of steady states was detected for
the problem with zero heat fluxes on two opposite lateral planes.


title:
Are the missing X-ray breaks in Gamma-ray Burst afterglow light curves
  merely hidden?

abstract:
  Gamma-ray burst afterglow observations in the Swift era have a perceived lack
of achromatic jet breaks compared to the BeppoSAX, or pre-Swift era.
Specifically, relatively few breaks, consistent with jet breaks, are observed
in the X-ray light curves of these bursts. If these breaks are truly missing,
it has serious consequences for the interpretation of GRB jet collimation and
energy requirements, and the use of GRBs as cosmological tools. Here we address
the issue of X-ray breaks that are possibly `hidden' and hence the light curves
are misinterpreted as being single power laws. We do so by synthesising XRT
light curves and fitting both single and broken power laws, and comparing the
relative goodness of each fit via Monte Carlo analysis. Even with the well
sampled light curves of the Swift era, these breaks may be left misidentified,
hence caution is required when making definite statements on the absence of
achromatic breaks.


title: Modeling the Gas Flow in the Bar of NGC 1365

abstract:
  We present new observations of the strongly-barred galaxy NGC 1365, including
new photometric images and Fabry-Perot spectroscopy, as well as a detailed
re-analysis of the neutral hydrogen observations from the VLA archive. We find
the galaxy to be at once remarkably bi-symmetric in its I-band light
distribution and strongly asymmetric in the distribution of dust and in the
kinematics of the gas in the bar region. The velocity field mapped in the
H-alpha line reveals bright HII regions with velocities that differ by 60 to 80
km/s from that of the surrounding gas, which may be due to remnants of
infalling material. We have attempted hydrodynamic simulations of the bar flow
to estimate the separate disk and halo masses, using two different dark matter
halo models and covering a wide range of mass-to-light ratios (Upsilon) and bar
pattern speeds (Omega_p). None of our models provides a compelling fit to the
data, but they seem most nearly consistent with a fast bar, corotation at sim
1.2r_B, and Upsilon_I simeq 2.0 +- 1.0, implying a massive, but not fully
maximal, disk. The fitted dark halos are unusually concentrated, a requirement
driven by the declining outer rotation curve.


title:
Paraxial Hamiltonian for photons in two-dimensional photonic crystal
  microstructures

abstract:
  New solid-state physics based approach is developed for analysis of the
paraxial light propagation in two-dimensional (2D) photonic lattices of coupled
dielectric waveguides or microcavities. In particular, using Maxwell's
equations, a non-Hermitian Hamiltonian eigenproblem with respect to the spinor
wave function of a photon is obtained for energy-dissipating photonic
microstructures. The Hamiltonian is suitable for almost the entire subclass of
2D structures encompassing arrays of semiconductor microcavities and
microstructured photonic crystal fibers, characterized by light propagating
mostly normal to the periodic lattice plane. Methods of numerical solution are
discussed and the formalism is applied to a square array of coupled
semiconductor microcavities, revealing reach possibilities for tailoring
photonic band structure both in the photon energy and photon lifetime energy
broadening domains. In particular, a feasibility to open a double photonic
crystal band gap simultaneously in the energy and lifetime energy broadening
domains is demonstrated.


title: BCS-BEC crossover in a strongly correlated Fermi gas

abstract:
  We study the BCS-BEC crossover in the strongly correlated regime of an
ultra-cold rotating two component Fermi gas. Strong correlations are shown to
generate an additional long-range interaction which results in a modified
crossover region compared to the non-rotating situation. The two-particle
correlation function reveals a smooth crossover between the s-wave paired
fermionic fractional quantum Hall state and the bosonic Laughlin state.


title: Simplicial resolutions and Ganea fibrations

abstract:
  In this work, we compare the two approximations of a path-connected space
$X$, by the Ganea spaces $G_n(X)$ and by the realizations $\|\Lambda_\bullet
X\|_{n}$ of the truncated simplicial resolutions emerging from the
loop-suspension cotriple $\Sigma\Omega$. For a simply connected space $X$, we
construct maps $\|\Lambda_\bullet X\|_{n-1}\to G_n(X)\to \|\Lambda_\bullet
X\|_{n}$ over $X$, up to homotopy. In the case $n=2$, we prove the existence of
a map $G_2(X)\to\|\Lambda_\bullet X\|_{1}$ over $X$ (up to homotopy) and
conjecture that this map exists for any $n$.


title:
p-adic L-functions and Selmer varieties associated to elliptic curves
  with complex multiplication

abstract:
  We show how non-vanishing of p-adic L functions controls the dimensions of
Selmer varieties associated to the complement of the origin in an elliptic
curve with CM. As a corollary, one obtains a \pi_1-proof of the theorem of
Siegel for such curves.


title:
The real loci of the Calogero-Moser spaces and the Shapiro-Shapiro
  conjecture

abstract:
  This paper has been withdrawn by the authors; it is superceeded by the paper:
The real loci of Calogero--Moser spaces, representations of rational Cherednik
algebras and the Shapiro conjecture, by Iain Gordon, Emil Horozov, and Milen
Yakimov, arXiv:0711.4336.


title: Single Molecule Photon Statistics from a Sequence of Laser Pulses

abstract:
  There are many ways of calculating photon statistics in quantum optics in
general and single molecule spectroscopy in particular such as the generating
function method, the quantum jump approach or time ordering methods. In this
paper starting with the optical Bloch equation, within the paths interpretation
of Zoller, Marte and Walls we obtain the photon statistics from a sequence of
laser pulses expressed by means of quantum trajectories. We find general
expressions for Pn(t) - the probability of emitting n photons up to time t,
discuss several consequences and show that the interpretation of the quantum
trajectories (i) emphasizes contribution to the photon statistics of the
coherence paths accumulated in the delay interval between the pulses and (ii)
allows simple classification of the terms negligible under certain physical
constraints . Applying this method to the concrete example of two square laser
pulses we find the probabilities of emitting 0,1 and 2 photons, examine several
limiting cases and investigate the upper and lower bounds of P0(t), P1(t) and
P2(t) for a sequence of two strong pulses in the limit of long measurement
times. Implication to single molecule non-linear spectroscopy and theory of
pairs of photons on demand are discussed briefly.


title:
A note on Berestycki-Cazenave's classical instability result for
  nonlinear Schr\"odinger equations

abstract:
  In this note we give an alternative, shorter proof of the classical result of
Berestycki and Cazenave on the instability by blow-up for the standing waves of
some nonlinear Schr\"odinger equations.


title: Habitable planets around the star Gl 581?

abstract:
  Radial velocity surveys are now able to detect terrestrial planets at
habitable distance from M-type stars. Recently, two planets with minimum masses
below 10 Earth masses were reported in a triple system around the M-type star
Gliese 581. Using results from atmospheric models and constraints from the
evolution of Venus and Mars, we assess the habitability of planets Gl 581c and
Gl 581d and we discuss the uncertainties affecting the habitable zone (HZ)
boundaries determination. We provide simplified formulae to estimate the HZ
limits that may be used to evaluate the astrobiological potential of
terrestrial exoplanets that will hopefully be discovered in the near future.
Planets Gl 581c and 'd' are near, but outside, what can be considered as the
conservative HZ. Planet 'c' receives 30% more energy from its star than Venus
from the Sun, with an increased radiative forcing caused by the spectral energy
distribution of Gl 581. Its habitability cannot however be positively ruled out
by theoretical models due to uncertainties affecting cloud properties.
Irradiation conditions of planet 'd' are comparable with those of early Mars.
Thanks to the warming effect of CO2-ice clouds planet 'd' might be a better
candidate for the first exoplanet known to be potentially habitable. A mixture
of various greenhouse gases could also maintain habitable conditions on this
planet.


title:
Act globally, compute locally: group actions, fixed points, and
  localization

abstract:
  Localization is a topological technique that allows us to make global
equivariant computations in terms of local data at the fixed points. For
example, we may compute a global integral by summing integrals at each of the
fixed points. Or, if we know that the global integral is zero, we conclude that
the sum of the local integrals is zero. This often turns topological questions
into combinatorial ones and vice versa. This expository article features
several instances of localization that occur at the crossroads of symplectic
and algebraic geometry on the one hand, and combinatorics and representation
theory on the other. The examples come largely from the symplectic category,
with particular attention to toric varieties. In the spirit of the 2006
International Conference on Toric Topology at Osaka City University, the main
goal of this exposition is to exhibit toric techniques that arise in symplectic
geometry.


title: Non-Fermi-Liquid Behavior from the Fermi-Liquid Approach

abstract:
  Non-Fermi liquid behavior of strongly correlated Fermi systems is derived
within the Landau approach. We attribute this behavior to a phase transition
associated with a rearrangement of the Landau state that leads to flattening of
a portion of the single-particle spectrum $\epsilon({\bf p})$ in the vicinity
of the Fermi surface. We demonstrate that the quasiparticle subsystem
responsible for the flat spectrum possesses the same thermodynamic properties
as a gas of localized spins. Theoretical results compare favorably with
available experimental data. While departing radically from prevalent views on
the origin of non-Fermi-liquid behavior, the theory advanced here is
nevertheless a conservative one of in continuing to operate within the general
framework of Landau theory.


title: Deep inelastic scattering off a N=4 SYM plasma at strong coupling

abstract:
  By using the AdS/CFT correspondence we study the deep inelastic scattering of
an R-current off a N=4 supersymmetric Yang-Mills (SYM) plasma at finite
temperature and strong coupling. Within the supergravity approximation valid
when the number of colors is large, we compute the structure functions by
solving Maxwell equations in the space-time geometry of the AdS_5 black
three-brane. We find a rather sharp transition between a low energy regime
where the scattering is weak and quasi-elastic, and a high-energy regime where
the current is completely absorbed. The critical energy for this transition
determines the plasma saturation momentum in terms of its temperature T and the
Bjorken x variable: Q_s=T/x. These results suggest a partonic picture for the
plasma where all the partons have transverse momenta below the saturation
momentum and occupation numbers of order one.


title:
The statistical mechanics of the two-dimensional hydrogen-bonding
  self-avoiding walk including solvent effects

abstract:
  A two-dimensional square-lattice model for the formation of secondary
structures in proteins, the hydrogen-bonding model, is extended to include the
effects of solvent quality. This is achieved by allowing
configuration-dependent nearest-neighbour interactions. The phase diagram is
presented, and found to have a much richer variety of phases than either the
pure hydrogen-bonding self-avoiding walk model or the standard $\Theta$-point
model.


title:
Multiscale expansion on the lattice and integrability of partial
  difference equations

abstract:
  We conjecture an integrability and linearizability test for dispersive
Z^2-lattice equations by using a discrete multiscale analysis. The lowest order
secularity conditions from the multiscale expansion give a partial differential
equation of the form of the nonlinear Schrodinger (NLS) equation. If the
starting lattice equation is integrable then the resulting NLS equation turns
out to be integrable, while if the starting equation is linearizable we get a
linear Schrodinger equation. On the other hand, if we start with a
non-integrable lattice equation we may obtain a non-integrable NLS equation.
This conjecture is confirmed by many examples.


title: Big Bang Nucleosynthesis Constraints on the Self-Gravity of Pressure

abstract:
  Using big bang nucleosynthesis and present, high-precision measurements of
light element abundances, we constrain the self-gravity of radiation pressure
in the early universe. The self-gravity of pressure is strictly non-Newtonian,
and thus the constraints we set provide a direct test of this prediction of
general relativity and of the standard, Robertson-Walker-Friedmann cosmology.


title:
An iterative algorithm for evaluating approximations to the optimal
  exercise boundary for a nonlinear Black-Scholes equation

abstract:
  The purpose of this paper is to analyze and compute the early exercise
boundary for a class of nonlinear Black--Scholes equations with a nonlinear
volatility which can be a function of the second derivative of the option price
itself. A motivation for studying the nonlinear Black--Scholes equation with a
nonlinear volatility arises from option pricing models taking into account e.g.
nontrivial transaction costs, investor's preferences, feedback and illiquid
markets effects and risk from a volatile (unprotected) portfolio. We present a
new method how to transform the free boundary problem for the early exercise
boundary position into a solution of a time depending nonlinear parabolic
equation defined on a fixed domain. We furthermore propose an iterative
numerical scheme that can be used to find an approximation of the free
boundary. We present results of numerical approximation of the early exercise
boundary for various types of nonlinear Black--Scholes equations and we discuss
dependence of the free boundary on various model parameters.


title: Does Amati Relation Depend on Luminosity of GRB's Host Galaxies?

abstract:
  In order to test systematic of the Amati relation, the 24 long-duration GRBs
with firmly determined $E_{\gamma,\mathrm{iso}}$ and $E_{\mathrm p}$ are
separated into two sub-groups according to B-band luminosity of their host
galaxies. The Amati relations in the two subgroups are found to be in agreement
with each other within uncertainties. Taking into account of the well
established luminosity - metallicity relation of galaxies, no strong evolution
of the Amati relation with GRB's environment metallicity is implied in this
study.


title:
Predictions for high energy neutrino cross-sections from the ZEUS global
  PDF fits

abstract:
  We have updated predictions for high energy neutrino and antineutrino charged
current cross-sections within the conventional DGLAP formalism of NLO QCD using
a modern PDF fit to HERA data, which also accounts in a systematic way for PDF
uncertainties deriving from both model uncertainties and from the experimental
uncertainties of the input data sets. Furthermore the PDFs are determined using
an improved treatment of heavy quark thresholds. A measurement of the neutrino
cross-section much below these predictions would signal the need for extension
of the conventional formalism as in BFKL resummation, or even gluon
recombination effects as in the colour glass condensate model.


title: Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer

abstract:
  We have studied temperature dependences of electron transport in graphene and
its bilayer and found extremely low electron-phonon scattering rates that set
the fundamental limit on possible charge carrier mobilities at room
temperature. Our measurements have shown that mobilities significantly higher
than 200,000 cm2/Vs are achievable, if extrinsic disorder is eliminated. A
sharp (threshold-like) increase in resistivity observed above approximately
200K is unexpected but can qualitatively be understood within a model of a
rippled graphene sheet in which scattering occurs on intra-ripple flexural
phonons.


title:
Comparison study for Level set and Direct Lagrangian methods for
  computing Willmore flow of closed planar curves

abstract:
  The main goal of this paper is to present results of comparison study for the
level set and direct Lagrangian methods for computing evolution of the Willmore
flow of embedded planar curves. To perform such a study we construct new
numerical approximation schemes for both Lagrangian as well as level set
methods based on semi-implicit in time and finite/complementary volume in space
discretizations. The Lagrangian scheme is stabilized in tangential direction by
the asymptotically uniform grid point redistribution. Both methods are
experimentally second order accurate. Moreover, we show precise coincidence of
both approaches in case of various elastic curve evolutions provided that
solving the linear systems in semi-implicit level set method is done in a
precise way, redistancing is performed occasionally and the influence of
boundary conditions on the level set function is eliminated.


title: Limits on additional planetary companions to OGLE-2005-BLG-390L

abstract:
  We investigate constraints on additional planets orbiting the distant M-dwarf
star OGLE-2005-BLG-390L, around which photometric microlensing data has
revealed the existence of the sub-Neptune-mass planet OGLE-2005-BLG-390Lb. We
specifically aim to study potential Jovian companions and compare our findings
with predictions from core-accretion and disc-instability models of planet
formation. We also obtain an estimate of the detection probability for
sub-Neptune mass planets similar to OGLE-2005-BLG-390Lb using a simplified
simulation of a microlensing experiment. We compute the efficiency of our
photometric data for detecting additional planets around OGLE-2005-BLG-390L, as
a function of the microlensing model parameters and convert it into a function
of the orbital axis and planet mass by means of an adopted model of the Milky
Way. We find that more than 50 % of potential planets with a mass in excess of
1 M_J between 1.1 and 2.3 AU around OGLE-2005-BLG-390L would have revealed
their existence, whereas for gas giants above 3 M_J in orbits between 1.5 and
2.2 AU, the detection efficiency reaches 70 %; however, no such companion was
observed. Our photometric microlensing data therefore do not contradict the
existence of gas giant planets at any separation orbiting OGLE-2005-BLG-390L.
Furthermore we find a detection probability for an OGLE-2005-BLG-390Lb-like
planet of around 2-5 %. In agreement with current planet formation theories,
this quantitatively supports the prediction that sub-Neptune mass planets are
common around low-mass stars.


title: Is the evidence for dark energy secure?

abstract:
  Several kinds of astronomical observations, interpreted in the framework of
the standard Friedmann-Robertson-Walker cosmology, have indicated that our
universe is dominated by a Cosmological Constant. The dimming of distant Type
Ia supernovae suggests that the expansion rate is accelerating, as if driven by
vacuum energy, and this has been indirectly substantiated through studies of
angular anisotropies in the cosmic microwave background (CMB) and of spatial
correlations in the large-scale structure (LSS) of galaxies. However there is
no compelling direct evidence yet for (the dynamical effects of) dark energy.
The precision CMB data can be equally well fitted without dark energy if the
spectrum of primordial density fluctuations is not quite scale-free and if the
Hubble constant is lower globally than its locally measured value. The LSS data
can also be satisfactorily fitted if there is a small component of hot dark
matter, as would be provided by neutrinos of mass 0.5 eV. Although such an
Einstein-de Sitter model cannot explain the SNe Ia Hubble diagram or the
position of the `baryon acoustic oscillation' peak in the autocorrelation
function of galaxies, it may be possible to do so e.g. in an inhomogeneous
Lemaitre-Tolman-Bondi cosmology where we are located in a void which is
expanding faster than the average. Such alternatives may seem contrived but
this must be weighed against our lack of any fundamental understanding of the
inferred tiny energy scale of the dark energy. It may well be an artifact of an
oversimplified cosmological model, rather than having physical reality.


title:
Spectral - Lagrangian methods for Collisional Models of Non -
  Equilibrium Statistical States

abstract:
  We propose a new spectral Lagrangian based deterministic solver for the
non-linear Boltzmann Transport Equation for Variable Hard Potential (VHP)
collision kernels with conservative or non-conservative binary interactions.
The method is based on symmetries of the Fourier transform of the collision
integral, where the complexity in its computing is reduced to a separate
integral over the unit sphere $S^2$. In addition, the conservation of moments
is enforced by Lagrangian constraints. The resulting scheme, implemented in
free space is very versatile and adjusts in a very simple manner, to several
cases that involve energy dissipation due to local micro-reversibility
(inelastic interactions) or elastic model of slowing down process. Our
simulations are benchmarked with the available exact self-similar solutions,
exact moment equations and analytical estimates for homogeneous Boltzmann
equation for both elastic and inelastic VHP interactions. Benchmarking of the
simulations involves the selection of a time self-similar rescaling of the
numerical distribution function which is performed using the continuous
spectrum of the equation for Maxwell molecules as studied first in
\cite{asympGranular} and generalized to a wide range of related models in
\cite{BCG}. The method also produces accurate results in the case of inelastic
diffusive Boltzmann equations for hard-spheres (inelastic collisions under
thermal bath), where overpopulated non-Gaussian exponential tails have been
conjectured in computations by stochastic methods in \cite{vanNoi-Ernst,
ernst-brito, MSS, GRW04} and rigourously proven in \cite{diffGran} and
\cite{highEnergyTails}.


title: Interpolation maps and congruence domains for wavelet sets

abstract:
  It is proven that if an interpolation map between two wavelet sets preserves
the union of the sets, then the pair must be an interpolation pair. We also
construct an example of a pair of wavelet sets for which the congruence domains
of the associated interpolation map and its inverse are equal, and yet the pair
is not an interpolation pair. The first result solves affirmatively a problem
that the second author had posed several years ago, and the second result
solves an intriguing problem of D. Han. The key to this counterexample is a
special technical lemma on constructing wavelet sets. Several other
applications of this result are also given. In addition, some problems are
posed. We also take the opportunity to give some general exposition on wavelet
sets and operator-theoretic interpolation of wavelets.


title: Twisting type N vacuums with cosmological constant

abstract:
  We provide the first examples of vacuum metrics with cosmological constant
which have a twisting quadruple principal null direction.


title: Gravitino Dark Matter and Light Element Adundances

abstract:
  We discuss the scenario where the gravitino is the lightest supersymmetric
particle and the long-lived next-to-lightest sparticle (NSP) is the neutralino
or the stau, the charged partner of the tau lepton. In this case staus form
bound states with several nuclei, affecting the cosmological abundances of Li6
and Li7 by enhancing nuclear rates that would otherwise be strongly suppressed.
We consider the effects of these enhanced rates on the final abundances
produced in Big-Bang nucleosynthesis (BBN), including injections of both
electromagnetic and hadronic energy during and after BBN. We show that if the
stau lifetime is longer than 10^3-10^4 s, the abundances of Li6 and Li7 are far
in excess of those allowed by observations. For shorter lifetimes of order 1000
s, it appears that stau bound state effect could reduce the Li7 abundance from
standard BBN values while at the same time enhancing the Li6 abundance,
creating a region where both lithium abundances match their plateau values.


title:
Charged current cross section for massive cosmological neutrinos
  impinging on radioactive nuclei

abstract:
  We discuss the cross section formula both for massless and massive neutrinos
on stable and radioactive nuclei. The latter could be of interest for the
detection of cosmological neutrinos whose observation is one of the main
challenges of modern cosmology. We analyze the signal to background ratio as a
function of the ratio of the neutrino mass over the detector resolution and
show that an energy resolution less than 0.5 eV would be required for sub-eV
neutrino masses, independently of the gravitational neutrino clustering.
Finally we mention the non-resonant character of neutrino capture on
radioactive nuclei.


title:
The Nature of the Vector and Scalar Potentials and Gauge Invariance in
  the Context of Gauge Theory

abstract:
  Modern undergraduate textbooks in electricity and magnetism typically focus
on a force representation of electrodynamics with an emphasis on Maxwell's
Equations and the Lorentz Force Law. The vector potential $\mathbf{A}$ and
scalar potential $\Phi$ play a secondary role mainly as quantities used to
calculate the electric and magnetic fields. However, quantum mechanics
including quantum electrodynamics (QED) and other gauge theories demands a
potential ($\Phi$,$\mathbf{A}$) oriented representation where the potentials
are the more fundamental quantities. Here, we help bridge that gap by showing
that the homogeneous Maxwell's equations together with the Lorentz Force Law
can be derived from assuming that the potentials represent potential energy and
momentum per unit charge. Furthermore, we enumerate the additional assumptions
that are needed to derive the inhomogeneous Maxwell's equations. As part of
this work we demonstrate the physical nature and importance of gauge
invariance.


title: On tangential stabilization in curvature driven flows of planar curves

abstract:
  We discuss the role of tangential stabilization in a curvature driven flow of
planar curves. The governing system of nonlinear parabolic equations includes a
nontrivial tangential velocity functional yielding a uniform redistribution of
grid points along the evolving family of curves preventing numerically computed
curves from forming various instabilities.


title: New Duality Relations for Classical Ground States

abstract:
  We derive new duality relations that link the energy of configurations
associated with a class of soft pair potentials to the corresponding energy of
the dual (Fourier-transformed) potential. We apply them by showing how
information about the classical ground states of short-ranged potentials can be
used to draw new conclusions about the nature of the ground states of
long-ranged potentials and vice versa. They also lead to bounds on the T=0
system energies in density intervals of phase coexistence, the identification
of a one-dimensional system that exhibits an infinite number of ``phase
transitions," and a conjecture regarding the ground states of purely repulsive
monotonic potentials.


title:
Some symmetry properties of spin currents and spin polarizations in
  multi-terminal mesoscopic spin-orbit coupled systems

abstract:
  We study theoretically some symmetry properties of spin currents and spin
polarizations in multi-terminal mesoscopic spin-orbit coupled systems. Based on
a scattering wave function approach, we show rigorously that in the equilibrium
state no finite spin polarizations can exist in a multi-terminal mesoscopic
spin-orbit coupled system (both in the leads and in the spin-orbit coupled
region) and also no finite equilibrium terminal spin currents can exist. By use
of a typical two-terminal mesoscopic spin-orbit coupled system as the example,
we show explicitly that the nonequilibrium terminal spin currents in a
multi-terminal mesoscopic spin-orbit coupled system are non-conservative in
general. This non-conservation of terminal spin currents is not caused by the
use of an improper definition of spin current but is intrinsic to
spin-dependent transports in mesoscopic spin-orbit coupled systems. We also
show that the nonequilibrium lateral edge spin accumulation induced by a
longitudinal charge current in a thin strip of \textit{finite} length of a
two-dimensional electronic system with intrinsic spin-orbit coupling may be
non-antisymmetric in general, which implies that some cautions may need to be
taken when attributing the occurrence of nonequilibrium lateral edge spin
accumulation induced by a longitudinal charge current in such a system to an
intrinsic spin Hall effect.


title: All superconformal surfaces in \R^4 in terms of minimal surfaces

abstract:
  We give an explicit construction of any simply-connected superconformal
surface $\phi\colon M^2\to \R^4$ in Euclidean space in terms of a pair of
conjugate minimal surfaces $g,h\colon M^2\to\R^4$. That $\phi$ is
superconformal means that its ellipse of curvature is a circle at any point. We
characterize the pairs $(g,h)$ of conjugate minimal surfaces that give rise to
images of holomorphic curves by an inversion in $\R^4$ and to images of
superminimal surfaces in either a sphere $\Sf^4$ or a hyperbolic space $\Hy^4$
by an stereographic projection. We also determine the relation between the
pairs $(g,h)$ of conjugate minimal surfaces associated to a superconformal
surface and its image by an inversion. In particular, this yields a new
transformation for minimal surfaces in $\R^4$.


title: Phase diagram of a Bose gas near a wide Feshbach resonance

abstract:
  In this paper, we study the phase diagram of a homogeneous Bose gas with a
repulsive interaction near a wide Feshbach resonance at zero temperature. The
Bose-Einstein-condensation (BEC) state of atoms is a metastable state. When the
scattering length $a$ exceeds a critical value depending on the atom density
$n$, $na^3>0.035$, the molecular excitation energy is imaginary and the atomic
BEC state is dynamically unstable against molecule formation. The BEC state of
diatomic molecules has lower energy, where the atomic excitation is gapped and
the molecular excitation is gapless. However when the scattering length is
above another critical value, $na^3>0.0164$, the molecular BEC state becomes a
unstable coherent mixture of atoms and molecules. In both BEC states, the
binding energy of diatomic molecules is reduced due to the many-body effect.

categories: cond-mat.other cond-mat.stat-mech cond-mat.str-el cond-mat.supr-con


title:
Methods for analytically estimating the resolution and intensity of
  neutron time-of-flight spectrometers. The case of the TOFTOF spectrometer

abstract:
  An analytical method is presented with allows to estimate the energy
resolution of time-of-flight neutron spectrometers, as well as its partial
contributions, over a dynamical range that extends from the elastic line to the
accessible inelastic regions. Such a method, already successfully applied in
the past to the TOSCA and HET neutron inelastic scattering spectrometers
installed at the ISIS neutron spallation source [A M Gaspar, PhD Thesis,
Universidade Tecnica de Lisboa, 2004], is here applied to the high resolution
time-of-flight spectrometer TOFTOF, mainly dedicated to quasi-elastic neutron
scattering studies and installed at the new neutron reactor FRM II. To make
such calculations easily understandable, the principle of work of the TOFTOF
instrument and of each of its components is explained in detail. A simply
method that can be used to estimate the instrument intensity, i.e. of the
number of neutrons arriving at the sample position per unit time, is also
briefly outlined.
  To the benefit of the TOFTOF users, graphs displaying the dependencies of the
instrument resolution at the elastic line and of the instrument intensity on
the relevant instrument parameters, i.e the wavelength of the incident
neutrons, the choppers speed of rotation and the frame overlap ratio, are
presented, in the form of iso-resolution or iso-intensity lines. The method of
estimation of the frame overlap ratio that is commonly used at time-of-flight
instruments such as TOFTOF is also explained and alternative options concerning
this parameter, depending on the dynamical range of interest, are briefly
addressed.


title: Precise predictions for h_a --> h_b h_c decays in the complex MSSM

abstract:
  Complete one-loop results for the decay widths of neutral Higgs bosons (h_a)
into lighter neutral Higgs bosons (h_b, h_c) are presented for the MSSM with
complex parameters. The results are obtained in the Feynman-diagrammatic
approach, taking into account the full dependence on the spectrum of
supersymmetric particles and all complex phases of the supersymmetric
parameters. The genuine triple-Higgs vertex contributions are supplemented with
two-loop propagator-type corrections, yielding the currently most precise
prediction for this class of processes. The genuine vertex corrections turn out
to be very important, yielding a large increase of the decay width compared to
a prediction based on the tree-level vertex. The new results are used to
analyse the impact of the experimental limits from the LEP Higgs searches on
the parameter space with a very light MSSM Higgs boson. It is found that a
significant part of the parameter space of the CPX benchmark scenario exists
where channels involving the decay h_2 --> h_1 h_1 have the highest search
sensitivity, and the existence of an unexcluded region with M_{h_1} \approx 45
GeV is confirmed.


title: The cmb dipole and existence of a center for expansion of the universe

abstract:
  It is shown that the observed cmb dipole implies the existence of a center
for the expansion of the universe, and that it can be explained by a
combination of peculiar velocity and Hubble flow.


title: An effective recursion formula for computing intersection numbers

abstract:
  We prove a new effective recursion formula for computing all intersection
indices (integrals of $\psi$ classes) on the moduli space of curves, inducting
only on the genus.


title: Multitopes are the same as principal ordered face structures

abstract:
  We show that the category of principal ordered face structures is equivalent
to the category of multitopes.
  We show that the category of principal ordered face structures is equivalent
to the category of multitopes. On the way we introduce the notion of a graded
tensor theory to state the abstract properties of the category of ordered face
structures and show how it fits into the recent work of T. Leinster and M.
Weber concerning the nerve construction.


title:
Deep spectroscopy of the FUV-optical emission lines from a sample of
  radio galaxies at z~2.5: metallicity and ionization

abstract:
  We present long-slit NIR spectra, obtained using the ISAAC instrument at the
Very Large Telescope, for nine radio galaxies at z~2.5. One-dimensional spectra
have been extracted and cross calibrated with optical spectra from the
literature to produce line spectra spanning a rest wavelength of ~1200-7000 A.
We have also produced a composite of the rest-frame UV-optical line fluxes of
powerful, z~2.5 radio galaxies. We have investigated the relative strengths of
Ly-alpha, H-beta, H-alpha, HeII 1640 and HeII 4687, and we find that Av can
vary significantly from object to object. In addition, we identify new line
ratios to calculate electron temperature: [NeV] 1575/[NeV] 3426, [NeIV]
1602/[NeIV] 2423, OIII] 1663/[OIII] 5008 and [OII] 2471/[OII]3728. We model the
emission line spectra and conclude they are best explained by
AGN-photoionization with the ionization parameter U varying between objects.
Single slab photoionization models are unable to reproduce the high- and the
low-ionization lines simultaneously: this may be alleviated either by combining
two or more single slab photoionization models with different U, or by using
mixed-medium models such as those of Binette, Wilson & Storchi-Bergmann (1996).
On the basis of NV/NIV] and NIV]/CIV we argue that shocks make a fractional
contribution to the ionization of the EELR. We find that in the EELR of z~2
radio galaxies the N/H abundance ratio is close to its solar value. We conclude
that N/H and metallicity do not vary by more than a factor of two in our
sample. This is consistent with the idea that massive ellipticals are assembled
very early in the history of the universe, and then evolve relatively passively
up to the present day.


title:
Anisotropies in insulating La$_{2-x}$Sr$_x$CuO$_4$: angular resolved
  photoemission and optical absorption

abstract:
  Due to the orthorhombic distortion of the lattice, the electronic hopping
integrals along the $a$ and $b$ diagonals, the orthorhombic directions, are
slightly different. We calculate their difference in the LDA and find
$t_{a}^{\prime}-t_{b}^{\prime}\approx 8 $meV. We argue that electron
correlations in the insulating phase of La$_{2-x}$Sr$_{x}$CuO$_{4}$, i. e. at
doping $x\leq 0.055,$ dramatically enhance the $(t_{a}^{\prime}-t_{b}^{\prime})
$-splitting between the $a$- and $b$-hole valleys. In particular, we predict
that the intensity of both angle-resolved photoemission and of optical
absorption is very different for the $a$ and $b$ nodal points.


title:
Partial separability and entanglement criteria for multiqubit quantum
  states

abstract:
  We explore the subtle relationships between partial separability and
entanglement of subsystems in multiqubit quantum states and give experimentally
accessible conditions that distinguish between various classes and levels of
partial separability in a hierarchical order. These conditions take the form of
bounds on the correlations of locally orthogonal observables. Violations of
such inequalities give strong sufficient criteria for various forms of partial
inseparability and multiqubit entanglement. The strength of these criteria is
illustrated by showing that they are stronger than several other well-known
entanglement criteria (the fidelity criterion, violation of Mermin-type
separability inequalities, the Laskowski-\.Zukowski criterion and the
D\"ur-Cirac criterion), and also by showing their great noise robustness for a
variety of multiqubit states, including N-qubit GHZ states and Dicke states.
Furthermore, for N greater than or equal to 3 they can detect bound entangled
states. For all these states, the required number of measurement settings for
implementation of the entanglement criteria is shown to be only N+1. If one
chooses the familiar Pauli matrices as single-qubit observables, the
inequalities take the form of bounds on the anti-diagonal matrix elements of a
state in terms of its diagonal matrix elements.


title: Escalating The War On SPAM Through Practical POW Exchange

abstract:
  Proof-of-work (POW) schemes have been proposed in the past. One prominent
system is HASHCASH (Back, 2002) which uses cryptographic puzzles . However,
work by Laurie and Clayton (2004) has shown that for a uniform proof-of-work
scheme on email to have an impact on SPAM, it would also be onerous enough to
impact on senders of "legitimate" email. I suggest that a non-uniform
proof-of-work scheme on email may be a solution to this problem, and describe a
framework that has the potential to limit SPAM, without unduly penalising
legitimate senders, and is constructed using only current SPAM filter
technology, and a small change to the SMTP (Simple Mail Transfer Protocol).
Specifically, I argue that it is possible to make sending SPAM 1,000 times more
expensive than sending "legitimate" email (so called HAM). Also, unlike the
system proposed by Debin Liu and Jean Camp (2006), it does not require the
complications of maintaining a reputation system.


title: Monotonicity formulas under rescaled Ricci flow

abstract:
  In this short notes, we discuss monotonicity formulas under various rescaled
versions of Ricci flow. The main result is Theorem \ref{theo rescaled}.


title:
The moduli space of cubic threefolds via degenerations of the
  intermediate Jacobian

abstract:
  A well known result of Clemens and Griffiths says that a smooth cubic
threefold can be recovered from its intermediate Jacobian. In this paper we
discuss the possible degenerations of these abelian varieties, and thus give a
description of the compactification of the moduli space of cubic threefolds
obtained in this way. The relation between this compactification and those
constructed in the work of Allcock-Carlson-Toledo and Looijenga-Swierstra is
also considered, and is similar in spirit to the relation between the various
compactifications of the moduli spaces of low genus curves.


title:
Search for vertical stratification of metals in atmospheres of blue
  horizontal-branch stars

abstract:
  The observed abundance peculiarities of many chemical species relative to the
expected cluster metallicity in blue horizontal-branch (BHB) stars presumably
appear as a result of atomic diffusion in the photosphere. The slow rotation
(typically $v\sin{i}<$ 10 km s$^{-1}$) of BHB stars with effective temperatures
$T_{\rm eff}>$ 11,500 K supports this idea since the diffusion mechanism is
only effective in a stable stellar atmosphere. In this work we search for
observational evidence of vertical chemical stratification in the atmospheres
of six hot BHB stars: B84, B267 and B279 in M15 and WF2-2541, WF4-3085 and
WF4-3485 in M13. We undertake an abundance stratification analysis of the
stellar atmospheres of the aforementioned stars, based on acquired Keck HIRES
spectra. We have found from our numerical simulations that three stars (B267,
B279 and WF2-2541) show clear signatures of the vertical stratification of iron
whose abundance increases toward the lower atmosphere, while the other two
stars (B84 and WF4-3485) do not. For WF4-3085 the iron stratification results
are inconclusive. B267 also shows a signature of titanium stratification. Our
estimates for radial velocity, $v\sin{i}$ and overall iron, titanium and
phosphorus abundances agree with previously published data for these stars
after taking the measurement errors into account. The results support the
hypothesis regarding the efficiency of atomic diffusion in the stellar
atmospheres of BHB stars with $T_{\rm eff}>$ 11,500 K.


title: Higgs boson decays in the Complex MSSM

abstract:
  The analysis of the Higgs search results at LEP showed that a part of the
MSSM parameter space with non-zero complex phases could not be excluded, where
the lightest neutral Higgs boson, h_1, has a mass of only about 45 GeV and the
second lightest neutral Higgs boson, h_2, has a sizable branching fraction into
a pair of h_1 states. Full one-loop results for the Higgs cascade decay h_2 -->
h_1 h_1 are presented and combined with two-loop Higgs propagator corrections
taken from the program FeynHiggs. Using the improved theoretical prediction to
analyse the limits on topological cross sections obtained at LEP, the existence
of an unexcluded region at low Higgs mass is confirmed. The effect of the
genuine vertex corrections on the size and shape of this region is discussed.


title: Leptonic Decays at BABAR

abstract:
  We present recent results on leptonic B decays using data collected by the
BaBar detector at the PEP-II asymmetric-energy e+e- collider at the Stanford
Linear Accelerator Center. We report searches for the B -> tau nu decay, based
on two statistically independent data samples.


title: Neutrosophic Relational Data Model

abstract:
  In this paper, we present a generalization of the relational data model based
on interval neutrosophic set. Our data model is capable of manipulating
incomplete as well as inconsistent information. Fuzzy relation or
intuitionistic fuzzy relation can only handle incomplete information.
Associated with each relation are two membership functions one is called
truth-membership function T which keeps track of the extent to which we believe
the tuple is in the relation, another is called falsity-membership function F
which keeps track of the extent to which we believe that it is not in the
relation. A neutrosophic relation is inconsistent if there exists one tuple a
such that T(a) + F(a) > 1 . In order to handle inconsistent situation, we
propose an operator called "split" to transform inconsistent neutrosophic
relations into pseudo-consistent neutrosophic relations and do the
set-theoretic and relation-theoretic operations on them and finally use another
operator called "combine" to transform the result back to neutrosophic
relation. For this data model, we define algebraic operators that are
generalizations of the usual operators such as intersection, union, selection,
join on fuzzy relations. Our data model can underlie any database and
knowledge-base management system that deals with incomplete and inconsistent
information.


title:
Direct Observation of Whispering Gallery Mode Polaritons and Their
  Dispersion in a ZnO Tapered Microcavity

abstract:
  We report direct observation of the strong exciton-photon coupling in ZnO
tapered whispering gallery (WG) microcavity at room temperature. By scanning
excitations along the tapered arm of ZnO tetrapod using micro-photoluminescence
spectrometer with different polarizations, we observed a transition from the
pure WG optical modes in the weak interaction regime to the excitonic polariton
in the strong coupling regime. The experimental observations are well described
by using the plane wave model including excitonic polariton dispersion
relation. This provides a direct mapping of the polariton dispersion, and thus
a comprehensive picture for coupling of different excitons with differently
polarized WG modes.


title:
Limits on the Production of Narrow t-tbar Resonances in p-pbar
  Collisions at sqrt(s)=1.96 TeV

abstract:
  We search for evidence of resonant top quark pair production in 955 pb-1 of
p-pbar collisions at sqrt(s)=1.96 TeV recorded with the CDF II detector at the
Fermilab Tevatron. For fully reconstructed candidate t-tbar events triggered on
leptons with large transverse momentum and containing at least one identified
b-quark jet, we compare the invariant mass spectrum of t-tbar pairs to the
expected superposition of standard model t-tbar, non-t-tbar backgrounds, and a
simple resonance model based on a sequential Z' boson. We establish upper
limits for sigma(p-pbar to Z') times Br(Z' to t-tbar) in the Z' mass interval
from 450 GeV/c2 to 900 GeV/c2. A topcolor leptophobic Z' is ruled out below 720
GeV/c2, and the cross section of any narrow Z'-like state decaying to t-tbar is
found to be less than 0.64 pb at 95% C.L. for M(Z') above 700 GeV/c2.


title: On injectivity of maps between Grothendieck groups induced by completion

abstract:
  We give an example of a local normal domain $R$ such that the map of
Grothendieck groups $\G(R) \to \G(\hat R)$ is not injective. We also raise some
questions about the kernel of that map.


title: Status of 2+1 flavor, 32^3x64 domain wall fermion simulations

abstract:
  We describe details of 1/a ~ 2.2Gev, L ~ 3 fm dynamical domain wall fermion
simulations which will allow us to do a more systematic continuum extrapolation
in combination with existing simu- lations. Details of the simulations such as
algorithm choices and machine performance, as well as results of basic
measurements are presented. These configurations are presently being generated
on the QCDOC machine at Edinburgh and the DOE QCDOC machine at Brookhaven as
part of a joint project with LHPC.


title: Weighted Random Popular Matchings

abstract:
  For a set A of n applicants and a set I of m items, we consider a problem of
computing a matching of applicants to items, i.e., a function M mapping A to I;
here we assume that each applicant $x \in A$ provides a preference list on
items in I. We say that an applicant $x \in A$ prefers an item p than an item q
if p is located at a higher position than q in its preference list, and we say
that x prefers a matching M over a matching M' if x prefers M(x) over M'(x).
For a given matching problem A, I, and preference lists, we say that M is more
popular than M' if the number of applicants preferring M over M' is larger than
that of applicants preferring M' over M, and M is called a popular matching if
there is no other matching that is more popular than M. Here we consider the
situation that A is partitioned into $A_{1},A_{2},...,A_{k}$, and that each
$A_{i}$ is assigned a weight $w_{i}>0$ such that w_{1}>w_{2}>...>w_{k}>0$. For
such a matching problem, we say that M is more popular than M' if the total
weight of applicants preferring M over M' is larger than that of applicants
preferring M' over M, and we call M an k-weighted popular matching if there is
no other matching that is more popular than M. In this paper, we analyze the
2-weighted matching problem, and we show that (lower bound) if
$m/n^{4/3}=o(1)$, then a random instance of the 2-weighted matching problem
with $w_{1} \geq 2w_{2}$ has a 2-weighted popular matching with probability
o(1); and (upper bound) if $n^{4/3}/m = o(1)$, then a random instance of the
2-weighted matching problem with $w_{1} \geq 2w_{2}$ has a 2-weighted popular
matching with probability 1-o(1).


title: Melting Crystal, Quantum Torus and Toda Hierarchy

abstract:
  Searching for the integrable structures of supersymmetric gauge theories and
topological strings, we study melting crystal, which is known as random plane
partition, from the viewpoint of integrable systems. We show that a series of
partition functions of melting crystals gives rise to a tau function of the
one-dimensional Toda hierarchy, where the models are defined by adding suitable
potentials, endowed with a series of coupling constants, to the standard
statistical weight. These potentials can be converted to a commutative
sub-algebra of quantum torus Lie algebra. This perspective reveals a remarkable
connection between random plane partition and quantum torus Lie algebra, and
substantially enables to prove the statement. Based on the result, we briefly
argue the integrable structures of five-dimensional $\mathcal{N}=1$
supersymmetric gauge theories and $A$-model topological strings. The
aforementioned potentials correspond to gauge theory observables analogous to
the Wilson loops, and thereby the partition functions are translated in the
gauge theory to generating functions of their correlators. In topological
strings, we particularly comment on a possibility of topology change caused by
condensation of these observables, giving a simple example.


title: Bounds on the Network Coding Capacity for Wireless Random Networks

abstract:
  Recently, it has been shown that the max flow capacity can be achieved in a
multicast network using network coding. In this paper, we propose and analyze a
more realistic model for wireless random networks. We prove that the capacity
of network coding for this model is concentrated around the expected value of
its minimum cut. Furthermore, we establish upper and lower bounds for wireless
nodes using Chernoff bound. Our experiments show that our theoretical
predictions are well matched by simulation results.


title: Adiabatic approximation in the second quantized formulation

abstract:
  Recently there have been some controversies about the criterion of the
adiabatic approximation. It is shown that an approximate diagonalization of the
effective Hamiltonian in the second quantized formulation gives rise to a
reliable and unambiguous criterion of the adiabatic approximation. This is
illustrated for the model of Marzlin and Sanders and a model related to the
geometric phase which can be exactly diagonalized in the present sense.


title:
Cosmological Density Fluctuations in Stochastic Gravity -- Formalism and
  Linear Analysis --

abstract:
  We study primordial perturbations generated from quantum fluctuations of an
inflaton based on the formalism of stochastic gravity. Integrating out the
degree of freedom of the inflaton field, we analyze the time evolution of the
correlation function of the curvature perturbation at tree level and compare it
with the prediction made by the gauge-invariant linear perturbation theory. We
find that our result coincides with that of the gauge-invariant perturbation
theory if the e-folding from the horizon crossing time is smaller than some
critical value ($\sim |$slow-roll parameter $|^{-1}$), which is the case for
the scales of the observed cosmological structures. However, in the limit of
the superhorizon scale, we find a discrepancy in the curvature perturbation,
which suggests that we should include the longitudinal part of the
gravitational field in the quantization of a scalar field even in stochastic
gravity.


title:
A geometric approach to maximum likelihood estimation of the functional
  principal components from sparse longitudinal data

abstract:
  In this paper, we consider the problem of estimating the eigenvalues and
eigenfunctions of the covariance kernel (i.e., the functional principal
components) from sparse and irregularly observed longitudinal data. We approach
this problem through a maximum likelihood method assuming that the covariance
kernel is smooth and finite dimensional. We exploit the smoothness of the
eigenfunctions to reduce dimensionality by restricting them to a lower
dimensional space of smooth functions. The estimation scheme is developed based
on a Newton-Raphson procedure using the fact that the basis coefficients
representing the eigenfunctions lie on a Stiefel manifold. We also address the
selection of the right number of basis functions, as well as that of the
dimension of the covariance kernel by a second order approximation to the
leave-one-curve-out cross-validation score that is computationally very
efficient. The effectiveness of our procedure is demonstrated by simulation
studies and an application to a CD4 counts data set. In the simulation studies,
our method performs well on both estimation and model selection. It also
outperforms two existing approaches: one based on a local polynomial smoothing
of the empirical covariances, and another using an EM algorithm.


title: Two addition theorems on polynomials of prime variables

abstract:
  We extend a recent result of Khalfalah and Szemeredi to the polynomials of
prime variables.


title:
Improved Constraints on the Acceleration History of the Universe and the
  Properties of the Dark Energy

abstract:
  We extend and apply a model-independent analysis method developed earlier by
Daly & Djorgovski to new samples of supernova standard candles, radio galaxy
and cluster standard rulers, and use it to constrain physical properties of the
dark energy as functions of redshift. Similar results are obtained for the
radio galaxy and supernova data sets. The first and second derivatives of the
distance are compared directly with predictions in a standard model based on
General Relativity. The good agreement indicates that General Relativity
provides an accurate description of the data on look-back time scales of about
ten billion years. The first and second derivatives are combined to obtain the
acceleration parameter, assuming only the validity of the Robertson-Walker
metric, independent of a theory of gravity and of the physical nature of the
dark energy. The acceleration of the universe at the current epoch is indicated
by the analysis. The effect of non-zero space curvature on q(z) is explored. We
solve for the pressure, energy density, equation of state, and potential and
kinetic energy of the dark energy as functions of redshift assuming that
General Relativity is the correct theory of gravity, and the results indicate
that a cosmological constant in a spatially flat universe provides a good
description of each of these quantities over the redshift range from zero to
about one. We define a new function, the dark energy indicator, in terms of the
first and second derivatives of the coordinate distance and show how this can
be used to measure deviations of w from -1 and to obtain a new and independent
measure of Omega.


title: Towards Weyl fermions on the lattice without artefacts

abstract:
  In spite of the breakthrough in non-perturbative chiral gauge theories during
the last decade, the present formulation has stubborn artefacts. Independently
of the fermion representation one is confronted with unwanted CP violation and
infinitely many undetermined weight factors. Renormalization group identifies
the culprit. We demonstrate the procedure on Weyl fermions in a real
representation.


abstract:
  Bounds for the maximal degree of certain Gr\"obner bases of simplicial toric
ideals are given. These bounds are close to the bound stated in Eisenbud-Goto's
Conjecture on the Castelnuovo-Mumford regularity.


title: Towards Grid Monitoring and deployment in Jade, using ProActive

abstract:
  This document describes our current effort to gridify Jade, a java-based
environment for the autonomic management of clustered J2EE application servers,
developed in the INRIA SARDES research team. Towards this objective, we use the
java ProActive grid technology. We first present some of the challenges to turn
such an autonomic management system initially dedicated to distributed
applications running on clusters of machines, into one that can provide
self-management capabilities to large-scale systems, i.e. deployed on grid
infrastructures. This leads us to a brief state of the art on grid monitoring
systems. Then, we recall the architecture of Jade, and consequently propose to
reorganize it in a potentially more scalable way. Practical experiments pertain
to the use of the grid deployment feature offered by ProActive to easily
conduct the deployment of the Jade system or its revised version on any sort of
grid.


title:
A scale-based approach to finding effective dimensionality in manifold
  learning

abstract:
  The discovering of low-dimensional manifolds in high-dimensional data is one
of the main goals in manifold learning. We propose a new approach to identify
the effective dimension (intrinsic dimension) of low-dimensional manifolds. The
scale space viewpoint is the key to our approach enabling us to meet the
challenge of noisy data. Our approach finds the effective dimensionality of the
data over all scale without any prior knowledge. It has better performance
compared with other methods especially in the presence of relatively large
noise and is computationally efficient.


title: SLOCC Convertibility between Two-Qubit States

abstract:
  In this paper we classify the four-qubit states that commute with
$U\otimes{U}\otimes{V}\otimes{V}$, where $U$ and $V$ are arbitrary members of
the Pauli group. We characterize the set of separable states for this class, in
terms of a finite number of entanglement witnesses. Equivalently, we
characterize the two-qubit, Bell-diagonal-preserving, completely positive maps
that are separable. These separable completely positive maps correspond to
protocols that can be implemented with stochastic local operations assisted by
classical communication (SLOCC). This allows us to derive a complete set of
SLOCC monotones for Bell-diagonal states, which, in turn, provides the
necessary and sufficient conditions for converting one two-qubit state to
another by SLOCC.


title:
Electronic structure and magnetic properties of pyroxenes
  (Li,Na)TM(Si,Ge)2O6: novel low-dimensional magnets with 90 bonds

abstract:
  The results of the LSDA+U calculations for pyroxenes with diverse magnetic
properties (Li,Na)TM(Si,Ge)$_2$O$_6$, where TM is the transition metal ion
(Ti,V,Cr,Mn,Fe), are presented. We show that the anisotropic orbital ordering
results in the spin-gap formation in NaTiSi$_2$O$_6$. The detailed analysis of
different contributions to the intrachain exchange interactions for pyroxenes
is performed both analytically using perturbation theory and basing on the
results of the band structure calculations. The antiferromagnetic
$t_{2g}-t_{2g}$ exchange is found to decrease gradually in going from Ti to Fe.
It turns out to be nearly compensated by ferromagnetic interaction between
half-filled $t_{2g}$ and empty $e_g$ orbitals in Cr-based pyroxenes. The
fine-tuning of the interaction parameters by the crystal structure results in
the ferromagnetism for NaCrGe$_2$O$_6$. Further increase of the total number of
electrons and occupation of $e_g$ sub-shell makes the $t_{2g}-e_g$ contribution
and total exchange interaction antiferromagnetic for Mn- and Fe-based
pyroxenes. Strong oxygen polarization was found in Fe-based pyroxenes. It is
shown that this effect leads to a considerable reduction of antiferromagnetic
intrachain exchange. The obtained results may serve as a basis for the analysis
of diverse magnetic properties of pyroxenes, including those with recently
discovered multiferroic behavior.


title: Hybrid States from Constituent Glue Model

abstract:
  The hybrid meson is one of the most interesting new hadron specie beyond the
naive quark model. It acquire a great attention both from the theoretical and
experimental efforts. Many good candidates have been claimed to be observed,
but there is no absolute confirmation about existence of hybrid mesons. In the
present work we propose new calculations of the masses and decay widths of the
hybrid mesons in the context of constituent gluon model.


title: Phase-shifts in stochastic resonance in a Chua circuit

abstract:
  We present an experimental study of stochastic resonance in an electronic
Chua circuit operating in the chaotic regime. We study in detail the
switch-phase distribution and the phase-shift between sinusoidal forcing for
two responses of the circuit: one depending on both inter-well and intra-well
dynamics and the other depending only on inter-well dynamics. We describe the
two relevant de-synchronizatrion mechanisms for high and low frequencies of the
forcing and present a method to detect the optimal noise intensity from switch
phases which coincides with the one derived from the observation of the
signal-to-noise ratio or residence times.


title:
Are ring galaxies the ancestors of giant low surface brightness
  galaxies?

abstract:
  We simulate the collisional formation of a ring galaxy and we integrate its
evolution up to 1.5 Gyr after the interaction. About 100-200 Myr after the
collision, the simulated galaxy is very similar to observed ring galaxies (e.g.
Cartwheel). After this stage, the ring keeps expanding and fades. Approximately
0.5-1 Gyr after the interaction, the disc becomes very large (~100 kpc) and
flat. Such extended discs have been observed only in giant low surface
brightness galaxies (GLSBs). We compare various properties of our simulated
galaxies (surface brightness profile, morphology, HI spectrum and rotation
curve) with the observations of four well-known GLSBs (UGC6614, Malin 1, Malin
2 and NGC7589). The simulations match quite well the observations, suggesting
that ring galaxies could be the progenitors of GLSBs. This result is crucial
for the cold dark matter (CDM) model, as it was very difficult, so far, to
explain the formation of GLSBs within the CDM scenario.


title: ANTARES alternative event reconstruction strategies

abstract:
  The ANTARES Collaboration is building a high-energy neutrino telescope at
2500 m depth in the Mediterranean Sea. The experiment aims to search for
high-energy cosmic neutrinos through the detection of Cerenkov light induced by
muons and showers resulting from neutrino interactions with the surrounding
medium. The detector will consist of a three-dimensional array of 900 optical
modules housing photomultipliers. It will be composed of 12 strings, 5 of them
being already in operation since January 2007. The muon track is reconstructed
from the arrival time and the charge of the signals obtained from the
photomultipliers, whose positions are known by means of an acoustic positioning
system. The reconstruction strategies include several steps among which there
are: optical background filtering, algorithms for first estimations of the
track parameters, and a final fit aiming to reach an angular resolution better
than 0.3 degree above 10 TeV in the full detector. Different reconstruction
strategies will be presented and their application to the present real data
analysis will be reviewed.


title:
Differential Fay identities and auxiliary linear problem of integrable
  hiearchies

abstract:
  We review the notion of differential Fay identities and demonstrate, through
case studies, its new role in integrable hierarchies of the KP type. These
identities are known to be a convenient tool for deriving dispersionless Hirota
equations. We show that differential (or, in the case of the Toda hierarchy,
difference) Fay identities play a more fundamental role. Namely, they are
nothing but a generating functional expression of the full set of auxiliary
linear equations, hence substantially equivalent to the integrable hierarchies
themselves. These results are illustrated for the KP, Toda, BKP and DKP
hierarchies. As a byproduct, we point out some new features of the DKP
hierarchy and its dispersionless limit.


title:
A survey of one-loop electroweak supersymmetric effects in stop-antistop
  production at LHC

abstract:
  This paper has been withdrawn by the authors because the analysis has been
extended in Ref.(arXiv:0804.1252) to the sbottom-antisbottom case.