title: Rupture by damage accumulation in rocks

abstract:
  The deformation of rocks is associated with microcracks nucleation and
propagation, i.e. damage. The accumulation of damage and its spatial
localization lead to the creation of a macroscale discontinuity, so-called
"fault" in geological terms, and to the failure of the material, i.e. a
dramatic decrease of the mechanical properties as strength and modulus. The
damage process can be studied both statically by direct observation of thin
sections and dynamically by recording acoustic waves emitted by crack
propagation (acoustic emission). Here we first review such observations
concerning geological objects over scales ranging from the laboratory sample
scale (dm) to seismically active faults (km), including cliffs and rock masses
(Dm, hm). These observations reveal complex patterns in both space (fractal
properties of damage structures as roughness and gouge), time (clustering,
particular trends when the failure approaches) and energy domains (power-law
distributions of energy release bursts). We use a numerical model based on
progressive damage within an elastic interaction framework which allows us to
simulate these observations. This study shows that the failure in rocks can be
the result of damage accumulation.


title: 44Ti nucleosynthesis gamma-ray lines with SIMBOL-X

abstract:
  In this contribution we discuss the 44Ti nucleosynthesis gamma-ray lines and
their visibility with SIMBOL-X from simulations based on its expected
sensitivity and spectro-imaging capabilities. The 44Ti radioactive nucleus can
provide invaluable information on the details of supernova explosions. Its
lifetime of about 85 yrs makes it the best indicator of the youth of these
stellar explosions through its three gamma-ray lines at 67.9, 78.4 keV and
1.157 MeV. We focus on the youngest Galactic supernova remnants, namely:
Cassiopeia A, for which the location and Doppler-velocity estimates of the
44Ti-emitting regions in the remnant would offer for the first time a unique
view of nucleosynthesis processes which occurred in the innermost layers of the
supernova; SN 1987A, in the Large Magellanic Cloud, whose progenitor is known,
and for which the expected measurement of these lines would greatly constrain
the stellar evolution models; Tycho and Kepler SNRs for which 44Ti lines have
never been detected so far. The issue of the "young, missing and hidden"
supernova remnants in the Galaxy will also be addressed using SIMBOL-X
observations at the position of the 44Ti excesses that wide-field instruments
like those onboard INTEGRAL and SWIFT/BAT should be able to reveal.


title: EM Cygni: a study of its eclipse timings

abstract:
  EM Cygni is a Z Cam-subtype eclipsing dwarf nova. Its orbital period
variations were reported in the past but the results were in conflict to each
other while other studies allowed the possibility of no period variation. In
this study we report accurate new times of minima of this eclipsing binary and
update its O-C diagram. We also estimate the mass transfer rate in EM Cygni
system and conclude that the mass transfer is far from the critical value. The
mass transfer rate determined from the eclipse timings is in agreement with the
spectroscopically determined value.


title: Funnel wall jets and the nature of the soft X-ray excess

abstract:
  The smooth soft X-ray excess seen in many type-1 AGN can be well described by
models of absorption in partially ionized material with a large velocity
dispersion, often physically interpreted as a radiatively driven accretion disk
wind. However, the state-of-the-art XSCORT code, which calculates the
photoionized radiative transfer through a differentially outflowing absorber,
shows that terminal velocities of order ~0.9c are required in order to
reproduce the soft X-ray excess. Such a high outflow velocity rules out UV-line
driving, continuum radiation driving, and thermal driving as mechanisms for
producing the wind. Entrainment of material by the magnetically driven jet is
the only plausible origin of such a high velocity flow, but numerical
simulations of jets and associated outflows do not currently show sufficient
material at high enough velocities to reproduce the soft X-ray excess. If the
soft excess is produced by absorption then it seems more likely that the
material is clumpy and/or only partially covers the source rather than forming
a continuous outflow.


title:
Seismic precursory patterns before a cliff collapse and critical-point
  phenomena

abstract:
  We analyse the statistical pattern of seismicity before a 1-2 103 m3 chalk
cliff collapse on the Normandie ocean shore, Western France. We show that a
power law acceleration of seismicity rate and energy in both 40 Hz-1.5 kHz and
2 Hz-10kHz frequency range, is defined on 3 order of magnitude, within 2 hours
from the collapse time. Simultaneously, the average size of the seismic events
increases toward the time to failure. These in-situ results are derived from
the only station located within one rupture length distance from the rock fall
rupture plane. They mimic the "critical point" like behavior recovered from
physical and numerical experiments before brittle failures and tertiary creep
failures. Our analysis of this first seismic monitoring data of a cliff
collapse suggests that the thermodynamic phase transition models for failure
may apply for cliff collapse.


title: The intracluster magnetic field power spectrum in Abell 2382

abstract:
  The goal of this work is to put constraints on the strength and structure of
the magnetic field in the cluster of galaxies A2382. We investigate the
relationship between magnetic field and Faraday rotation effects in the
cluster, using numerical simulations as a reference for the observed
polarization properties. For this purpose we present Very Large Array
observations at 20 cm and 6 cm of two polarized radio sources embedded in
A2382, and we obtained detailed rotation measure images for both of them. We
simulated random three-dimensional magnetic field models with different power
spectra and thus produced synthetic rotation measure images. By comparing our
simulations with the observed polarization properties of the radio sources, we
can determine the strength and the power spectrum of intra-cluster magnetic
field fluctuations that best reproduce the observations. The data are
consistent with a power law magnetic field power spectrum with the Kolmogorov
index $n=11/3$, while the outer scale of the magnetic field fluctuations is of
the order of 35 kpc. The average magnetic field strength at the cluster center
is about 3 $\mu$G and decreases in the external region as the square root of
the electron gas density. The average magnetic field strength in the central 1
Mpc$^{3}$ is about 1 $\mu$G.


title: Quantum Fluctuations in the Superfluid State of the BCS-BEC Crossover

abstract:
  We determine the effects of quantum fluctuations about the T=0 mean field
solution of the BCS-BEC crossover in a dilute Fermi gas using the functional
integral method. These fluctuations are described in terms of the zero point
motion of collective modes and the virtual scattering of gapped quasiparticles.
We calculate their effects on various measurable properties, including chemical
potential, ground state energy, the gap, the speed of sound and the Landau
critical velocity. At unitarity, we find excellent agreement with quantum Monte
Carlo and experimental results. In the BCS limit, we show analytically that we
obtain Fermi liquid interaction corrections to thermodynamics including the
Hartree shift. In the BEC limit, we show that the theory leads to an
approximate description of the reduction of the scattering length for bosonic
molecules and also obtain quantum depletion of the Lee-Yang form. At the end of
the paper, we describe a method to include feedback of quantum fluctuations
into the gap equation, and discuss the problems of self-consistent calculations
in satisfying Goldstone's theorem and obtaining ultraviolet finite results at
unitarity.


title:
Impurity and quaternions in nonrelativistic scattering from a quantum
  memory

abstract:
  Models of quantum computing rely on transformations of the states of a
quantum memory. We study mathematical aspects of a model proposed by Wu in
which the memory state is changed via the scattering of incoming particles.
This operation causes the memory content to deviate from a pure state, i.e.
induces impurity. For nonrelativistic particles scattered from a two-state
memory and sufficiently general interaction potentials in 1+1 dimensions, we
express impurity in terms of quaternionic commutators. In this context, pure
memory states correspond to null hyperbolic quaternions. In the case with point
interactions, the scattering process amounts to appropriate rotations of
quaternions in the frequency domain. Our work complements a previous analysis
by Margetis and Myers (2006 J. Phys. A 39 11567--11581).


title:
Hyperfine structure of the metastable 3P2 state of alkaline earth atoms
  as an accurate probe of nuclear magnetic octupole moments

abstract:
  Measuring the hyperfine structure (HFS) of long-lived $^3P_2$ states of
divalent atoms may offer the opportunity of extracting relatively unexplored
nuclear magnetic octupole and electric hexadecapole moments. Here, using
relativistic many-body methods of atomic structure and the nuclear shell model,
we evaluate the effect of these higher nuclear moments on the hyperfine
structure. We find that the sensitivity of HFS interval measurements in
$^{87}$Sr needed to reveal the perturbation caused by the nuclear octupole
moment is on the order of kHz. Results of similar analyses for $^{9}$Be,
$^{25}$Mg, and $^{43}$Ca are also reported.


title: On homogeneous pinning models and penalizations

abstract:
  In this note, we show how the penalization method, introduced in order to
describe some non-trivial changes of the Wiener measure, can be applied to the
study of some simple polymer models such as the pinning model. The bulk of the
analysis is then focused on the study of a martingale which has to be computed
as a Markovian limit.


title:
A momentum-space representation of Green's functions with modified
  dispersion on ultra-static space-time

abstract:
  We consider the Green's functions associated to a scalar field propagating on
a curved, ultra-static background, in the presence of modified dispersion
relations. The usual proper-time deWitt-Schwinger procedure to obtain a series
representation of the Green's functions is doomed to failure, because of higher
order spatial derivatives in the Klein-Gordon operator. We show how to overcome
this difficulty by considering a preferred frame, associated to a unit
time-like vector. With respect to this frame, we can express the Green's
functions as an integral over all frequencies of a space-dependent function.
The latter can be expanded in momentum space, as a series with geometric
coefficients similar to the deWitt-Schwinger's ones. By integrating over all
frequencies, we finally find the expansion of the Green's function up to four
derivatives of the metric tensor. The relation with the proper-time formalism
is also discussed.


title:
Large-scale variations of the cosmic X-ray background and the X-ray
  emissivity of the local Universe

abstract:
  We study the cosmic X-ray background (CXB) intensity variations on large
angular scales using slew data of the RXTE observatory. We detect intensity
variations up to ~2% on angular scales of 20--40deg. These variations are
partly correlated with the local large-scale structure, which allowed us to
estimate the emissivity of the local Universe in the energy band 2--10 keV at
9+/-4 x 10^{38} ers/sec/Mpc^{3}. The spectral energy distribution of the
large-angular-scale variations is hard and is compatible with that of the CXB,
which implies that normal galaxies and clusters of galaxies, whose spectra are
typically much softer, do not contribute more than 15% to the total X-ray
emissivity of the local Universe. Most of the observed CXB anisotropy (after
exclusion of point sources with fluxes >10^{-11} erg/s/cm^2) can be attributed
to low-luminosity AGNs


title: Growth of toric domains in the smectic phase of oxadiazoles

abstract:
  In a previous paper (Phase Transitions, 80(9), 987, 2007) we discussed the
smectic and nematic textures of some mesomorphic oxadiazole compounds with
terminal Cl-substituent. Optical microscope investigations showed a very
interesting behaviour of smectic and nematic phases; the smectic phase has
fan-shaped and toric textures and the nematic phase has spherulitic domains,
which disappear as the sample is further heated, the texture changing into a
smooth one. Here, we investigate four oxadiazole compounds with the same
structure but terminal Br-substituent. The behaviour of the smectic and nematic
phases is like that observed in the compounds with Cl. The focus of the paper
is on the growth of toric domains from the nematic melt and on the role of
defects in the domain structure.


title:
From Slow to Superluminal Propagation: Dispersive Properties of Surface
  Plasmon Polaritons in Linear Chains of Metallic Nanospheroids

abstract:
  We consider propagation of surface plasmon polaritons (SPPs) in linear
periodic chains (LPCs) of prolate and oblate metallic spheroids. We show that
the SPP group velocity can be efficiently controlled by varying the aspect
ratio of the spheroids. For sufficiently small aspect ratios, a gap appears in
the first Brillouin zone of the chain lattice in which propagating modes do not
exist. depending on the SPP polarization, the gap extends to certain intervals
of the Bloch wave number q. Thus, for transverse polarization, no propagating
SPPs exist with wave numbers q such that q_c^\perp < | q | < \pi/h, h being the
chain period. For longitudinally polarized SPPs, the gap spans the interval
|q|<q_c^\parallel. Here q_c^\perp and q_c^\parallel are different constants
which depend on the chain parameters, spheroid aspect ratio and its orientation
with respect to the chain axis. The dependence of the dispersion curves on the
spheroid aspect ratio leads to a number of interesting effects. In particular,
bandwidth of SPPs that can propagate in an LPC can be substantially increased
by utilizing prolate or oblate spheroids. When q is close to a critical value,
so that |q - q_c^\perp|<<\pi/h or |q - q_c^\parallel|<<\pi/h, the decay length
of the SPPs is dramatically increased. In addition, the dispersion curves
acquire a very large positive or negative slope. This can be used to achieve
superluminal group velocity for realistic chain parameters. We demonstrate
superluminal propagation of Gaussian wave packets in numerical simulations.
Both theory and simulations are based on Maxwell equations with account of
retardation and, therefore, are fully relativistic.


title: A Note On Mixed Mean Inequalities

abstract:
  We give a simpler proof of a result of Holland concerning a mixed
arithmetic-geometric mean inequality. We also prove a result of mixed mean
inequality involving the symmetric means.


title:
Shannon-McMillan theorems for discrete random fields along curves and
  lower bounds for surface-order large deviations

abstract:
  The notion of a surface-order specific entropy h_c(P) of a two-dimensional
discrete random field P along a curve c is introduced as the limit of rescaled
entropies along lattice approximations of the blowups of c. Existence is shown
by proving a corresponding Shannon-McMillan theorem. We obtain a representation
of h_c(P) as a mixture of specific entropies along the tangent lines of c. As
an application, the specific entropy along curves is used to refine Foellmer
and Ort's lower bound for the large deviations of the empirical field of an
attractive Gibbs measure from its ergodic behavior in the phase-transition
regime.


title: Regularity of the density for the stochastic heat equation

abstract:
  We study the smoothness of the density of a semilinear heat equation with
multiplicative spacetime white noise. Using Malliavin calculus, we reduce the
problem to a question of negative moments of solutions of a linear heat
equation with multiplicative white noise. Then we settle this question by
proving that solutions to the linear equation have negative moments of all
orders.


title:
Reference Frame Fields based on Quantum Theory Representations of Real
  and Complex Numbers

abstract:
  A quantum theory representations of real (R) and complex (C) numbers is given
that is based on states of single, finite strings of qukits for any base k > 1.
Both unary representations and the possibility that qukits with k a prime
number are elementary and the rest composite are discussed. Cauchy sequences of
qukit string states are defined from the arithmetic properties. The
representations of R and C, as equivalence classes of these sequences, differ
from classical kit string state representations in two ways: the freedom of
choice of basis states, and the fact that each quantum theory representation is
part of a mathematical structure that is itself based on the real and complex
numbers. These aspects enable the description of 3 dimensional frame fields
labeled by different k values, different basis or gauge choices, and different
iteration stages. The reference frames in the field are based on each R and C
representation where each frame contains representations of all physical
theories as mathematical structures based on the R and C representation.
Approaches to integrating this with physics are described. It is observed that
R and C values of physical quantities, matrix elements, etc. which are viewed
in a frame as elementary and featureless, are seen in a parent frame as
equivalence classes of Cauchy sequences of qukit string states.


title: Top Quark Physics at the Tevatron

abstract:
  The Tevatron proton-antiproton collider at Fermilab with its centre of mass
energy of 1.96 TeV is currently the only source for the production of top
quarks. Its increased luminosity and centre of mass energy in Run II allow both
collider detectors CDF and D0 to study top quarks with unprecedented scrutiny.
  Recent results on the top quark's pair production cross section and its
properties such as mass, electric charge, helicity of the W boson in its decay
and branching fraction B(t->Wb) are presented and probe the validity of the
Standard Model.


title: Spinflation

abstract:
  We study the cosmological implications of including angular motion in the DBI
brane inflation scenario. The non-canonical kinetic terms of the
Dirac-Born-Infeld action give an interesting alternative to slow roll
inflation, and cycling branes can drive periods of accelerated expansion in the
Universe. We present explicit numerical solutions demonstrating brane inflation
in the Klebanov-Strassler throat. We find that demanding sufficient inflation
takes place in the throat is in conflict with keeping the brane's total energy
low enough so that local gravitational backreaction on the Calabi-Yau manifold
can be safely ignored. We deduce that spinflation (brane inflation with angular
momentum) can ease this tension by providing extra e-foldings at the start of
inflation. Cosmological expansion rapidly damps the angular momentum causing an
exit to a more conventional brane inflation scenario. Finally, we set up a
general framework for cosmological perturbation theory in this scenario, where
we have multi-field non-standard kinetic term inflation.


title:
Cantor Spectrum for Schr\"odinger Operators with Potentials arising from
  Generalized Skew-shifts

abstract:
  We consider continuous $SL(2,\mathbb{R})$-cocycles over a strictly ergodic
homeomorphism which fibers over an almost periodic dynamical system
(generalized skew-shifts). We prove that any cocycle which is not uniformly
hyperbolic can be approximated by one which is conjugate to an
$SO(2,\mathbb{R})$-cocycle. Using this, we show that if a cocycle's homotopy
class does not display a certain obstruction to uniform hyperbolicity, then it
can be $C^0$-perturbed to become uniformly hyperbolic. For cocycles arising
from Schr\"odinger operators, the obstruction vanishes and we conclude that
uniform hyperbolicity is dense, which implies that for a generic continuous
potential, the spectrum of the corresponding Schr\"odinger operator is a Cantor
set.


title: Higgs Production by Gluon initiated Weak Boson Fusion

abstract:
  The gluon-gluon induced terms for Higgs production through weak-boson fusion
are calculated. They form a finite and gauge-invariant subset of the NNLO
corrections in the strong coupling constant. This is also the lowest order with
sizeable t-channel colour exchange contributions, leading to additional
hadronic activity between the outgoing jets.


title: Two-Dimensional Fluctuating Vesicles in Linear Shear Flow

abstract:
  The stochastic motion of a two-dimensional vesicle in linear shear flow is
studied at finite temperature. In the limit of small deformations from a
circle, Langevin-type equations of motion are derived, which are highly
nonlinear due to the constraint of constant perimeter length. These equations
are solved in the low temperature limit and using a mean field approach, in
which the length constraint is satisfied only on average. The constraint
imposes non-trivial correlations between the lowest deformation modes at low
temperature. We also simulate a vesicle in a hydrodynamic solvent by using the
multi-particle collision dynamics technique, both in the quasi-circular regime
and for larger deformations, and compare the stationary deformation correlation
functions and the time autocorrelation functions with theoretical predictions.
Good agreement between theory and simulations is obtained.


title: Finding Optimal Flows Efficiently

abstract:
  Among the models of quantum computation, the One-way Quantum Computer is one
of the most promising proposals of physical realization, and opens new
perspectives for parallelization by taking advantage of quantum entanglement.
Since a one-way quantum computation is based on quantum measurement, which is a
fundamentally nondeterministic evolution, a sufficient condition of global
determinism has been introduced as the existence of a causal flow in a graph
that underlies the computation. A O(n^3)-algorithm has been introduced for
finding such a causal flow when the numbers of output and input vertices in the
graph are equal, otherwise no polynomial time algorithm was known for deciding
whether a graph has a causal flow or not. Our main contribution is to introduce
a O(n^2)-algorithm for finding a causal flow, if any, whatever the numbers of
input and output vertices are. This answers the open question stated by Danos
and Kashefi and by de Beaudrap. Moreover, we prove that our algorithm produces
an optimal flow (flow of minimal depth.)
  Whereas the existence of a causal flow is a sufficient condition for
determinism, it is not a necessary condition. A weaker version of the causal
flow, called gflow (generalized flow) has been introduced and has been proved
to be a necessary and sufficient condition for a family of deterministic
computations. Moreover the depth of the quantum computation is upper bounded by
the depth of the gflow. However, the existence of a polynomial time algorithm
that finds a gflow has been stated as an open question. In this paper we answer
this positively with a polynomial time algorithm that outputs an optimal gflow
of a given graph and thus finds an optimal correction strategy to the
nondeterministic evolution due to measurements.


title: A Back-reaction Induced Lower Bound on the Tensor-to-Scalar Ratio

abstract:
  There are large classes of inflationary models, particularly popular in the
context of string theory and brane world approaches to inflation, in which the
ratio of linearized tensor to scalar metric fluctuations is very small. In such
models, however, gravitational waves produced by scalar modes cannot be
neglected. We derive the lower bound on the tensor-to-scalar ratio by
considering the back-reaction of the scalar perturbations as a source of
gravitational waves. These results show that no cosmological model that is
compatible with a metric scalar amplitude of $\approx 10^{-5}$ can have a ratio
of the tensor to scalar power spectra less than $\approx 10^{-8}$ at
recombination and that higher-order terms leads to logarithmic growth for r
during radiation domination. Our lower bound also applies to non-inflationary
models which produce an almost scale-invariant spectrum of coherent
super-Hubble scale metric fluctuations.


title: Description of two soliton collision for the quartic gKdV equation

abstract:
  This paper concerns the problem of collision of two solitons for the quartic
generalized Korteweg-de Vries equation. We introduce a new framework to
describe the collision in the special case where one soliton is small with
respect to the other. We prove that the two soliton survive the collision, we
describe the collision phenomenon (computation of the first order of the
resulting shifts on the solitons). Moreover, we prove that in this situation,
there does not exist pure two-soliton solutions.


title: No axions in light shinning through a wall experiments

abstract: This paper has been withdrawn and a new version will be submitted soon


title:
The Unusual Variability of the Large Magellanic Cloud Planetary Nebula
  RPJ 053059-683542

abstract:
  We present images and light curves of the bipolar Planetary Nebula RPJ
053059-683542 that was discovered in the Reid-Parker AAO/UKST H-alpha survey of
the Large Magellanic Cloud (LMC). The emission from this object appears
entirely nebular, with the central star apparently obscured by a central band
of absorption that bisects the nebula. The light curves, which were derived
from images from the SuperMACHO project at CTIO, showed significant, spatially
resolved variability over the period 2002 January through 2005 December.
Remarkably, the emission from the two bright lobes of the nebula vary either
independently, or similarly but with a phase lag of at least one year. The
optical spectra show a low level of nebular excitation, and only modest N
enrichment. Infrared photometry from the 2MASS and SAGE surveys indicates the
presence of a significant quantity of dust. The available data imply that the
central star has a close binary companion, and that the system has undergone
some kind of outburst event that caused the nebular emission to first brighten
and then fade. Further monitoring, high-resolution imaging, and detailed IR
polarimetry and spectroscopy would uncover the nature of this nebula and the
unseen ionizing source.


title: Spectra of alternating Hilbert operators

abstract:
  Spectra of real alternating operators seem to be quite interesting from the
view point of explaining the Riemann Hypothesis for various zeta functions.
Unfortunately we have not sufficient experiments concerning this theme.
Necessary works would be to supply new examples of spectra related to zeros and
poles of zeta functions. A century ago Hilbert (1907) considered a kind of
operators representing quadratic forms of infinitely many variables.
Demonstrating the calculation of spectra for alternating Hilbert operators we
hope to present a novel scheme in this paper. Authors expect this study
encourages experts for further studies.


title: The first polarimetric signatures of infrared jets in X-ray binaries

abstract:
  We present near-infrared linear spectropolarimetry of a sample of persistent
X-ray binaries, Sco X-1, Cyg X-2 and GRS1915+105. The slopes of the spectra are
shallower than what is expected from a standard steady-state accretion disc,
and can be explained if the near-infrared flux contains a contribution from an
optically thin jet. For the neutron star systems, Sco X-1 and Cyg X-2, the
polarization levels at 2.4um are 1.3+/-0.10% and 5.4+/-0.7% respectively which
is greater than the polarization level at 1.65um. This cannot be explained by
interstellar polarization or electron scattering in the anisotropic environment
of the accretion flow. We propose that the most likely explanation is that this
is the polarimetric signature of synchrotron emission arising from close to the
base of the jets in these systems. In the black hole system GRS1915+105 the
observed polarization, although high (5.0+/-1.2% at 2.4um), may be consistent
with interstellar polarization. For Sco X-1 the position angle of the radio jet
on the sky is approximately perpendicular to the near-infrared position angle
(electric vector), suggesting that the magnetic field is aligned with the jet.
These observations may be a first step towards probing the ordering, alignment
and variability of the outflow magnetic field in a region closer to the central
accreting object than is observed in the radio band.


title: Stability of two soliton collision for nonintegrable gKdV equations

abstract:
  We continue our study of the collision of two solitons for the subcritical
generalized KdV equations. In a previous paper, mainly devoted to the case of
the quartic gKdV equation, we have introduced a new framework to understand the
collision of two solitons in the case where one soliton is small with respect
to the other. In this paper, we consider the case of a general nonlinearity
$f(u)$ for which the two solitons are nonlinearly stable. We prove that in this
situation the two solitons survive and we describe the collision at the main
orders.


title:
S-Parameter Uncertainties in Network Analyzer Measurements with
  Application to Antenna Patterns

abstract:
  An analytical method was developed, to estimate uncertainties in full
two-port Vector Network Analyzer measurements, using total differentials of
S-parameters. System error uncertainties were also estimated from total
differentials involving two triples of standards, in the Direct Through
connection case. Standard load uncertainties and measurement inaccuracies were
represented by independent differentials. Complex uncertainty in any quantity,
differentiably dependent on S-parameters, is estimated by the corresponding
Differential Error Region. Real uncertainties, rectangular and polar, are
estimated by the orthogonal parallelogram and annular sector circumscribed
about the Differential Error Region, respectively. From the user's point of
view, manufactures' data may be used to set the independent differentials and
apply the method. Demonstration results include: (1) System error differentials
for Short, matching Load and Open pairs of opposite sex standards; (2) System
error uncertainties for VNA extended by two lengthy transmission lines of
opposite sex end-connectors; (3) High uncertainties in Z-parameters against
frequency of an appropriately designed, DC resistive, T-Network; (4) Moderate
uncertainties in amplitude and phase patterns of a designed UHF radial discone
antenna (azimuthally rotated by a built positioner, under developed software
control of a built hardware controller) polarization coupled with a constructed
gain standard antenna (stationary) into an anechoic chamber.


title: CP Violation in SUSY Particle Production and Decay

abstract:
  Recent studies about CP violation in the Minimal Supersymmetric Standard
Model (MSSM) with complex parameters are reviewed. In order to unambiguously
identify the CP-violating phenomena it is necessary to study CP-odd or T-odd
observables. In chargino and neutralino production and decay at the
International Linear Collider (ILC) triple product asymmetries and asymmetries
defined via transverse beam polarization have been analyzed. It has been found
that these asymmetries can be measured at the ILC in a large region of the MSSM
parameter space and are thus an important tool to establish CP violation in
supersymmetry.


title: Topological properties of the contact network of granular packings

abstract:
  The force networks of different granular ensembles are defined and their
topological properties studied using the tools of complex networks. In
particular, for each set of grains compressed in a square box, it is introduced
a force threshold that determines which contacts conform the network. Hence,
the topological characteristics of the network are analyzed as a function of
this parameter. The characterization of the structural features thus obtained,
may be useful in the understanding of the macroscopic physical behavior
exhibited by this class of media.


title: Dirac fermions at the H point of graphite: Magneto-transmission studies

abstract:
  We report on far infrared magneto-transmission measurements on a thin
graphite sample prepared by exfoliation of highly oriented pyrolytic graphite.
In magnetic field, absorption lines exhibiting a blue-shift proportional to
sqrtB are observed. This is a fingerprint for massless Dirac holes at the H
point in bulk graphite. The Fermi velocity is found to be c*=1.02x10^6 m/s and
the pseudogap at the H point is estimated to be below 10 meV. Although the
holes behave to a first approximation as a strictly 2D gas of Dirac fermions,
the full 3D band structure has to be taken into account to explain all the
observed spectral features.


title: Unified continuum approach to crystal surface morphological relaxation

abstract:
  A continuum theory is used to predict scaling laws for the morphological
relaxation of crystal surfaces in two independent space dimensions. The goal is
to unify previously disconnected experimental observations of decaying surface
profiles. The continuum description is derived from the motion of interacting
atomic steps. For isotropic diffusion of adatoms across each terrace, induced
adatom fluxes transverse and parallel to step edges obey different laws,
yielding a tensor mobility for the continuum surface flux. The partial
differential equation (PDE) for the height profile expresses an interplay of
step energetics and kinetics, and aspect ratio of surface topography that
plausibly unifies observations of decaying bidirectional surface corrugations.
The PDE reduces to known evolution equations for axisymmetric mounds and
one-dimensional periodic corrugations.


title: Test Stand Measurements for an ILC Polarimeter

abstract:
  The setup of two different small scale teststands for measurements regarding
an electron Cherenkov detector as part of the ILC polarimeters is presented.
Component measurements already carried out are analyzed and others, foreseen
for the near future, are discussed. The larger one of the two teststands
features the old Cherenkov detector of the SLD experiment, which will be used
as a reference for a number of crucial measurements. Especially, the
requirements for the non-linearity of the read-out chain are studied in greater
detail and methods for its precise measurement before and during operation are
being developed accordingly.


title: Winner-take-all selection in a neural system with delayed feedback

abstract:
  We consider the effects of temporal delay in a neural feedback system with
excitation and inhibition. The topology of our model system reflects the
anatomy of the avian isthmic circuitry, a feedback structure found in all
classes of vertebrates. We show that the system is capable of performing a
`winner-take-all' selection rule for certain combinations of excitatory and
inhibitory feedback. In particular, we show that when the time delays are
sufficiently large a system with local inhibition and global excitation can
function as a `winner-take-all' network and exhibit oscillatory dynamics. We
demonstrate how the origin of the oscillations can be attributed to the finite
delays through a linear stability analysis.


title: Long time deviation from exponential decay: non-integral power laws

abstract:
  Quantal systems are predicted to show a change-over from exponential decay to
power law decay at very long times. Although most theoretical studies predict
integer power-law exponents, recent measurements by Rothe et al. of decay
luminescence of organic molecules in solution {Phys. Rev. Lett. 96 (2006)
163601} found non-integer exponents in most cases. We propose a physical
mechanism, within the realm of scattering from potentials with long tails,
which produces a continuous range of power law exponents. In the tractable case
of the repulsive inverse square potential, we demonstrate a simple relation
between the strength of the long range tail and the power law exponent. This
system is amenable to experimental scrutiny.


title: A Stochastic Mean-Field Approach For Nuclear Dynamics

abstract:
  We propose a microscopic stochastic approach to improve description of
nuclear dynamics beyond the mean-field approximation at low energies. It is
shown that, for small amplitude fluctuations, the proposed model gives a result
for the dispersion of a one-body observable that is identical to the result
obtained previously through a variational approach. Furthermore, by projecting
the proposed stochastic mean-field evolution on a collective path, a
generalized Langevin equation is derived for collective variable, which
incorporate one-body dissipation and one-body fluctuation mechanism in
accordance with quantal fluctuation-dissipation relation.


title: Optimal test-configurations for toric varieties

abstract:
  On a K-unstable toric variety we show the existence of an optimal
destabilising convex function. We show that if this is piecewise linear then it
gives rise to a decomposition into semistable pieces analogous to the
Harder-Narasimhan filtration of an unstable vector bundle. We also show that if
the Calabi flow exists for all time on a toric variety then it minimises the
Calabi functional. In this case the infimum of the Calabi functional is given
by the supremum of the normalised Futaki invariants over all destabilising
test-configurations, as predicted by a conjecture of Donaldson.


title:
N\'eel and Valence-Bond Crystal phases of the Two-Dimensional Heisenberg
  Model on the Checkerboard Lattice

abstract:
  I use an improved version of the two-step density matrix renormalization
group method to study ground-state properties of the 2D Heisenberg model on the
checkerboard lattice. In this version the Hamiltonian is projected on a tensor
product of two-leg ladders instead of chains. This allows investigations of 2D
isotropic models. I show that this method can describe both the magnetically
disordered and ordered phases. The ground-state phases of the checkerboard
model as $J_2$ increases are: (i) N\'eel with $Q=(\pi,\pi)$, (ii) a valence
bond crystal (VBC) of plaquettes, (iii) N\'eel with $Q=(\pi/2,\pi)$, and (iv) a
VBC of crossed dimers. In agreement with previous results, I find that at the
isotropic point $J_2=J_1$, the ground state is made of weakly interacting
plaquettes with a large gap $\Delta \approx 0.67 J_1$ to triplet excitations.


title: An algorithm for solving the Independent Set problem

abstract: This paper has been withdrawn by the author, due an error in claim 1.


title:
Magnetic order and spin fluctuations in low-dimensional insulating
  systems

abstract:
  The current theoretical and experimental situations are reviewed for
low-dimensional insulating systems with a low magnetic transition temperature
TM and pronounced short-range magnetic order above this temperature. Both the
standard and self-consistent spin-wave theories are shown to be insufficient to
quantitatively describe the experimental data on these systems.
Field-theoretical approaches taking into account the contribution of the
spin-fluctuation excitations (neglected in the spin-wave theories) to the
thermodynamic properties of ferro- and antiferromagnets are discussed.


title: Constraints and the E10 Coset Model

abstract:
  We continue the study of the one-dimensional E10 coset model (massless
spinning particle motion on E10/K(E10) whose dynamics at low levels is known to
coincide with the equations of motion of maximal supergravity theories in
appropriate truncations. We show that the coset dynamics (truncated at levels
less or equal to three) can be consistently restricted by requiring the
vanishing of a set of constraints which are in one-to-one correspondence with
the canonical constraints of supergravity. Hence, the resulting constrained
sigma-model dynamics captures the full (constrained) supergravity dynamics in
this truncation. Remarkably, the bosonic constraints are found to be
expressible in a Sugawara-like (current x current) form in terms of the
conserved E10 Noether current, and transform covariantly under an upper
parabolic subgroup E10+ of E10. We discuss the possible implications of this
result, and in particular exhibit a tantalising link with the usual affine
Sugawara construction in the truncation of E10 to its affine subgroup E9.


title: Large-Nc Regge models and the <A^2> condensate

abstract:
  We explore the role of the <A^2> gluon condensate in matching Regge models to
the operator product expansion of meson correlators.


title: The Neon Abundance in the Ejecta of QU Vul From Late-Epoch IR Spectra

abstract:
  We present ground-based SpectroCam-10 mid-infrared, MMT optical, and Spitzer
Space Telescope IRS mid-infrared spectra taken 7.62, 18.75, and 19.38 years
respectively after the outburst of the old classical nova QU Vulpeculae (Nova
Vul 1984 #2). The spectra of the ejecta are dominated by forbidden line
emission from neon and oxygen. Our analysis shows that neon was, at the first
and last epochs respectively, more than 76 and 168 times overabundant by number
with respect to hydrogen compared to the solar value. These high lower limits
to the neon abundance confirm that QU Vul involved a thermonuclear runaway on
an ONeMg white dwarf and approach the yields predicted by models of the
nucleosynthesis in such events.


title: Innovation Success and Structural Change: An Abstract Agent Based Study

abstract:
  A model is developed to study the effectiveness of innovation and its impact
on structure creation and structure change on agent-based societies. The
abstract model that is developed is easily adapted to any particular field. In
any interacting environment, the agents receive something from the environment
(the other agents) in exchange for their effort and pay the environment a
certain amount of value for the fulfilling of their needs or for the very price
of existence in that environment. This is coded by two bit strings and the
dynamics of the exchange is based on the matching of these strings to those of
the other agents. Innovation is related to the adaptation by the agents of
their bit strings to improve some utility function.


title: Bimodality and hysteresis in systems driven by confined L\'evy flights

abstract:
  We demonstrate occurrence of bimodality and dynamical hysteresis in a system
describing an overdamped quartic oscillator perturbed by additive white and
asymmetric L\'evy noise. Investigated estimators of the stationary probability
density profiles display not only a turnover from unimodal to bimodal character
but also a change in a relative stability of stationary states that depends on
the asymmetry parameter of the underlying noise term. When varying the
asymmetry parameter cyclically, the system exhibits a hysteresis in the
occupation of a chosen stationary state.


title: Sylow's theorem for Moufang loops

abstract:
  For finite Moufang loops, we prove an analog of the first Sylow theorem
giving a criterion of the existence of a p-Sylow subloop. We also find the
maximal order of p-subloops in the Moufang loops that do not possess p-Sylow
subloops.


title: Line Shapes of the X(3872)

abstract:
  If the quantum numbers of the X(3872) are J^{PC}=1^{++}, the measurement of
its mass implies that it is either a loosely-bound hadronic molecule whose
constituents are a superposition of the charm mesons pairs D^{*0} Dbar^0 and
D^0 Dbar^{*0} or else it is a virtual state of these charm mesons. Its binding
energy is small enough that the decay width of a constituent D^{*0} or
Dbar^{*0} has a significant effect on the line shapes of the X resonance. We
develop a simple approximation to the line shapes that takes into account the
effect of the D^{*0} width as well as inelastic scattering channels of the
charm mesons. We carry out a simultaneous fit to the line shapes in the J/psi
pi^+ pi^- and D^0 Dbar^0 pi^0 channels measured in the decays B^+ to K^+ + X by
the Belle Collaboration. The best fit corresponds to the X(3872) being a bound
state just below the D^{*0} Dbar^0 threshold, but a virtual state just above
the D^{*0} D-ar^0 threshold is not excluded.


title: Minimal conductivity of rippled graphene with topological disorder

abstract:
  We study the transport properties of a neutral graphene sheet with curved
regions induced or stabilized by topological defects. The proposed model gives
rise to Dirac fermions in a random magnetic field and in the random space
dependent Fermi velocity induced by the curvature. This last term leads to
singular long range correlated disorder with special characteristics. The Drude
minimal conductivity at zero energy is found to be inversely proportional to
the density of topological disorder, a signature of diffusive behavior.


title:
Validating relativistic models of nuclear structure against theoretical,
  experimental, and observational constraints

abstract:
  Relativistic mean-field models of nuclear structure have been enormously
successful at reproducing ground-state properties of finite nuclei throughout
the periodic table using a handful of accurately calibrated parameters. In this
contribution we use powerful theoretical, experimental, and observational
constraints -- not employed in the calibration procedure -- to validate two
such models: NL3 and FSUGold. It is observed that FSUGold is consistent with
all these constraints, except perhaps for a high density equation of state that
appears mildly softer than required by astronomical observations. It is argued
that incorporating such constrains goes a long way in removing much of the
ambiguity left over from the standard calibrating procedure.


title: Automorphisms of higher-dimensional right-angled Artin groups

abstract:
  We study the algebraic structure of the automorphism group of a general
right-angled Artin group. We show that this group is virtually torsion-free and
has finite virtual cohomological dimension. This generalizes results proved by
the authors and John Crisp (arXiv:math/0610980) for two-dimensional
right-angled Artin groups.


title: Extending the optimum interval method

abstract:
  The optimum interval method for finding an upper limit of a one-dimensionally
distributed signal in the presence of an unknown background is extended to the
case of high statistics. There is also some discussion of how the method can be
extended to the multiple dimensional case.


title: Fourier series on fractals: a parallel with wavelet theory

abstract:
  We study orthogonality relations for Fourier frequencies and complex
exponentials in Hilbert spaces $L^2(\mu)$ with measures $\mu$ arising from
iterated function systems (IFS). This includes equilibrium measures in complex
dynamics. Motivated by applications, we draw parallels between analysis of
fractal measures on the one hand, and the geometry of wavelets on the other.
  We are motivated by spectral theory for commuting partial differential
operators and related duality notions. While stated initially for bounded and
open regions in $\br^d$, they have since found reformulations in the theory of
fractals and wavelets. We include a historical sketch with questions from early
operator theory.


title:
Disentanglement and decoherence in a pair of qutrits under dephasing
  noise

abstract:
  We relate disentanglement and decoherence rates in a pair of three-level
atoms subjected to multi-local and collective pure dephasing noise acting in a
preferred basis. The bipartite entanglement decay rate, as bounded from above
by the negativity, is found to be greater than or equal to the
dephasing-decoherence rates characterized by the decay of off-diagonal elements
in the corresponding full density matrix describing the system or the reduced
density matrix describing either qutrit, extending previous results for qubit
pairs subject to such noise.


title: On RSA Moduli with Almost Half of the Bits Prescribed

abstract:
  We show that using character sum estimates due to H. Iwaniec leads to an
improvement of recent results about the distribution and finding RSA moduli
$M=pl$, where $p$ and $l$ are primes, with prescribed bit patterns. We are now
able to specify about $n$ bits instead of about $n/2$ bits as in the previous
work. We also show that the same result of H. Iwaniec can be used to obtain an
unconditional version of a combinatorial result of W. de Launey and D. Gordon
that was originally derived under the Extended Riemann Hypothesis.


title: Classification of connecting solutions of semilinear parabolic equations

abstract:
  For a given semilinear parabolic equation with polynomial nonlinearity, many
solutions blow up in finite time. For a certain large class of these equations,
we show that some of the solutions which do not blow up actually tend to
equilibria. The characterizing property of such solutions is a finite energy
constraint, which comes about from the fact that this class of equations can be
written as the $L^2$ gradient of a certain functional.


title: B(Ds^+ -> l^+ nu) and the Decay Constant f_(D_s^+)

abstract:
  I report final CLEO-c results on the purely leptonic decays of the D_s^+ ->
l^+ nu, for the cases when l^+ is a mu^+ or tau^+, when it decays into pi^+
anti-nu, using 314/pb of data at 4.170 GeV. I also include preliminary results
from the tau^+ -> e^+ nu anti-nu channel using 195/pb. Combining both we
measure f_{D_s}= 275 +/- 10 +/- 5 MeV, and f_{D_s^+}/{f_{D^+}=1.24 +/- 0.10 =/-
0.03 .


title:
Electrical expression of spin accumulation in ferromagnet/semiconductor
  structures

abstract:
  We treat the spin injection and extraction via a ferromagnetic
metal/semiconductor Schottky barrier as a quantum scattering problem. This
enables the theory to explain a number of phenomena involving spin-dependent
current through the Schottky barrier, especially the counter-intuitive spin
polarization direction in the semiconductor due to current extraction seen in
recent experiments. A possible explanation of this phenomenon involves taking
into account the spin-dependent inelastic scattering via the bound states in
the interface region. The quantum-mechanical treatment of spin transport
through the interface is coupled with the semiclassical description of
transport in the adjoining media, in which we take into account the in-plane
spin diffusion along the interface in the planar geometry used in experiments.
The theory forms the basis of the calculation of spin-dependent current flow in
multi-terminal systems, consisting of a semiconductor channel with many
ferromagnetic contacts attached, in which the spin accumulation created by spin
injection/extraction can be efficiently sensed by electrical means. A
three-terminal system can be used as a magnetic memory cell with the bit of
information encoded in the magnetization of one of the contacts. Using five
terminals we construct a reprogrammable logic gate, in which the logic inputs
and the functionality are encoded in magnetizations of the four terminals,
while the current out of the fifth one gives a result of the operation.


title: de Sitter limit of inflation and nonlinear perturbation theory

abstract:
  We study the fourth order action of the comoving curvature perturbation in an
inflationary universe in order to understand more systematically the de Sitter
limit in nonlinear cosmological perturbation theory. We derive the action of
the curvature perturbation to fourth order in the comoving gauge, and show that
it vanishes sufficiently fast in the de Sitter limit. By studying the de Sitter
limit, we then extrapolate to the n'th order action of the comoving curvature
perturbation and discuss the slow-roll order of the n-point correlation
function.


title: Resummation and NLO Matching of Event Shapes with Effective Field Theory

abstract:
  The resummed differential thrust rate in e+e- annihilation is calculated
using Soft-Collinear Effective Theory (SCET). The resulting distribution in the
two-jet region T~1 is found to agree with the corresponding expression derived
by the standard approach. A matching procedure to account for finite
corrections at T < 1 is then described. There are two important advantages of
the SCET approach. First, SCET manifests a dynamical seesaw scale q = p^2/Q in
addition to the center-of-mass energy Q and the jet mass scale p ~ Q ~ sqrt(1 -
T). Thus, the resummation of logs of p/q can be cleanly distinguished from the
resummation of logs of Q/p. Second, finite parts of loop amplitudes appear in
specific places in the perturbative distribution: in the matching to the hard
function, at the scale Q, in matching to the jet function, at the scale p, and
in matching to the soft function, at the scale q. This allows for a consistent
merger of fixed order corrections and resummation. In particular, the total NLO
e+e- cross section is reproduced from these finite parts without having to
perform additional infrared regulation.


title: Extension of log pluricanonical forms from subvarieties

abstract:
  In this paper, I prove a very general extension theorem for log
pluricanonical systems. The main application of this extension theorem is
(together with Kawamata's subadjunction theorem) to give an optimal
subadjunction theorem which relates the positivities of canonical bundle of the
ambient projective manifold and that of the (maximal) center of log canonical
singularities. This is an extension of the corresponding result in my previous
work where I dealt with log pluricanonical systems of general type. This
subadjunction theorem indicates an approach to solve the abundance conjecture
for canonical divisors (or log canonical divisors) in terms of the induction in
dimension.


title:
Population synthesis at short wavelengths and spectrophotometric
  diagnostic tools for galaxy evolution

abstract:
  Taking advantage of recent important advances in the calculation of
high-resolution spectral grids of stellar atmospheres at short wavelengths, and
their implementation for population synthesis models, we briefly review here
some special properties of ultraviolet emission in SSPs, and discuss their
potential applications for identifying and tuning up effective diagnostic tools
to probe distinctive evolutionary properties of early-type galaxies and other
evolved stellar systems.


title:
Clustering properties of ultrahigh energy cosmic rays and the search for
  their astrophysical sources

abstract:
  The arrival directions of ultrahigh energy cosmic rays (UHECRs) may show
anisotropies on all scales, from just above the experimental angular resolution
up to medium scales and dipole anisotropies. We find that a global comparison
of the two-point auto-correlation function of the data with the one of
catalogues of potential sources is a powerful diagnostic tool. In particular,
this method is far less sensitive to unknown deflections in magnetic fields
than cross-correlation studies while keeping a strong discrimination power
among source candidates. We illustrate these advantages by considering ordinary
galaxies, gamma ray bursts and active galactic nuclei as possible sources.
Already the sparse publicly available data suggest that the sources of UHECRs
may be a strongly clustered sub-sample of galaxies or of active galactic
nuclei. We present forecasts for various cases of source distributions which
can be checked soon by the Pierre Auger Observatory.


title: On the Signed Small Ball Inequality

abstract:
  This paper is a companion to our prior paper arXiv:0705.4619 on the `Small
Ball Inequality in All Dimensions.' In it, we address a more restrictive
inequality, and obtain a non-trivial, explicit bound, using a single essential
estimate from our prior paper. The prior bound was not explicit and much more
involved.


title:
Adaptive Optics Rest-Frame V-band Imaging of Lyman Break Galaxies at
  z~3: High-surface Density Disk-like Galaxies ?

abstract:
  In order to reveal the rest-frame V-band morphology of galaxies at z~3, we
conducted AO-assisted K-band imaging observations of z~3 LBGs with Mv*-0.5 to
Mv*+3.0 mag. LBGs brighter than Mv* have larger rHL (0.40") than the fainter
LBGs (0.23") on average, and there is no bright LBGs with a small rHL. The LBGs
brighter than Mv* have red rest-frame U-V colors (average of 0.2 mag) and most
of the fainter LBGs show blue rest-frame U-V colors (average of -0.4 mag). The
K-band peaks of some of the LBGs brighter than K=22.0 mag show significant
shift from those in the optical images. The images of all but one of the LBGs
with K<21.5 mag are fitted well with Sersic profile with n index less than 2,
similar to disk galaxies in the local universe. Assuming that the LBGs have a
disk-shape, we compared their size-luminosity and size-stellar mass relation
with those of z=0 and z=1 disk galaxies. The LBGs are brighter than z=0 and z=1
disk galaxies at the same effective radius. The rest-frame V-band surface
brightness of the LBGs are 2.2-2.9 mag and 1.2-1.9 mag brighter than the disk
galaxies at z=0 and z=1, respectively. The size-stellar mass relation of the
LBGs shows that the effective radii of the LBGs do not depend on their stellar
mass. For the LBGs brighter than Mv*, the average surface stellar mass density
is 3-6 times larger than those of the z=0 and z=1 disk galaxies. We also
examine the profiles of the serendipitously observed DRGs. They are also fitted
with the Sersic profiles with n<2. The implications of the dominance of n<2
population among galaxies at z~3 and the presence of the high surface stellar
mass density disk systems are discussed.


title: Search for CP Violation in the Decays D0 --> K- K+ and D0 --> pi- pi+

abstract:
  We measure CP-violating asymmetries of neutral charmed mesons in the modes D0
--> K- K+ and D0 --> pi- pi+ with the highest precision to date by using D0 -->
K- pi+ decays to correct detector asymmetries. An analysis of 385.8 fb-1 of
data collected with the BaBar detector yields values of aCP(KK) = (0.00 +/-
0.34 (stat.) +/- 0.13 (syst.))% and aCP(pipi) = (-0.24 +/- 0.52 (stat.) +/-
0.22 (syst.))%, which agree with Standard Model predictions.


title: Formation and properties of metal-oxygen atomic chains

abstract:
  Suspended chains consisting of single noble metal and oxygen atoms have been
formed. We provide evidence that oxygen can react with and be incorporated into
metallic one-dimensional atomic chains. Oxygen incorporation reinforces the
linear bonds in the chain, which facilitates the creation of longer atomic
chains. The mechanical and electrical properties of these diatomic chains have
been investigated by determining local vibration modes of the chain and by
measuring the dependence of the average chain-conductance on the length of the
chain. Additionally, we have performed calculations that give insight in the
physical mechanism of the oxygen-induced strengthening of the linear bonds and
the conductance of the metal-oxygen chains.


title:
Autocorrelations and Thermal Fragility of Anyonic Loops in Topologically
  Quantum Ordered Systems

abstract:
  Are systems that display Topological Quantum Order (TQO), and have a gap to
excitations, hardware fault-tolerant at finite temperatures? We show that in
surface code models that display low d-dimensional Gauge-Like Symmetries, such
as Kitaev's and its generalizations, the expectation value of topological
symmetry operators vanishes at any non-zero temperature, a phenomenon that we
coined thermal fragility. The autocorrelation time for the non-local
topological quantities in these systems may remain finite even in the
thermodynamic limit. We provide explicit expressions for the autocorrelation
functions in Kitaev's model. If temperatures far below the gap may be achieved
then these autocorrelation times, albeit finite, can be made large. The
physical engine behind the loss of correlations at large spatial and/or
temporal distance is the proliferation of topological defects at any finite
temperature as a result of a dimensional reduction. This raises an important
question: How may we best quantify the degree of protection of quantum
information in a topologically ordered system at finite temperature?


title: Quasar optical variability and black hole mass

abstract:
  In order to investigate the dependence of quasar optical-UV variability on
fundamental physical parameters like black hole mass, we have matched quasars
from the QUEST1 variability survey with broad-lined objects from the SDSS.
Black hole masses and bolometric luminosities are estimated from Sloan spectra,
and variability amplitudes from the QUEST1 light curves. Long-term variability
amplitudes (rest-frame time scales 0.5--2 yrs) are found to correlate with
black hole mass at the 99% significance level or better. This means that
quasars with larger black hole masses have larger percentage flux variations.
Partial rank correlation analysis shows that the correlation cannot explained
by obvious selection effects inherent to flux-limited samples. We discuss
whether the correlation is a manifestation of a relation between BH mass and
accretion disk thermal time scales, or if it is due to changes in the optical
depth of the accretion disk with black hole mass. Perhaps the most likely
explanation is that the more massive black holes are starving, and produce
larger flux variations because they do not have a steady inflow of gaseous
fuel.


title: Wide Field Hard X-ray Survey Telescope: ProtoEXIST1

abstract:
  We report our progress on the development of pixellated imaging CZT detector
arrays for our first-generation balloon-borne wide-field hard X-ray (20 - 600
keV) telescope, ProtoEXIST1. Our ProtoEXIST program is a pathfinder for the
High Energy Telescope (HET) on the Energetic X-ray Imaging Survey telescope
(EXIST), a proposed implementation of the Black Hole Finder Probe. ProtoEXIST1
consists of four independent coded-aperture telescopes with close-tiled (~0.4
mm gaps) CZT detectors that preserve their 2.5mm pixel pitch. Multiple
shielding/field-of-view configurations are planned to identify optimal geometry
for the HET in EXIST. The primary technical challenge in ProtoEXIST is the
development of large area, close-tiled modules of imaging CZT detectors (1000
cm2 for ProtoEXIST1), with all readout and control systems for the ASIC readout
vertically stacked. We describe the overall telescope configuration of
ProtoEXIST1 and review the current development status of the CZT detectors,
from individual detector crystal units (DCUs) to a full detector module (DM).
We have built the first units of each component for the detector plane and have
completed a few Rev2 DCUs (2x2 cm2), which are under a series of tests. Bare
DCUs (pre-crystal bonding) show high, uniform ASIC yield (~70%) and ~30%
reduction in electronics noise compared to the Rev1 equivalent. A Rev1 DCU
already achieved ~1.2% FWHM at 662 keV, and preliminary analysis of the initial
radiation tests on a Rev2 DCU shows ~ 4 keV FWHM at 60 keV (vs. 4.7 keV for
Rev1). We therefore expect about <~1% FWHM at 662 keV with the Rev2 detectors.


title: Equivariant Dixmier-Douady Classes

abstract:
  An equivariant bundle gerbe \`a la Meinrenken over a $G$-manifold $M$ is
known to be a special type of $S^1$-gerbe over the differentiable stack
$[M/G]$. We prove that the natural morphism relating the Cartan and simplicial
models of equivariant cohomology in degree 3 maps the Dixmier-Douady class of
an equivariant bundle gerbe \`a la Meinrenken to the Behrend-Xu-Dixmier-Douady
class of the corresponding $S^1$-gerbe.


title:
Pricing, Competition, and Routing for Selfish and Strategic Nodes in
  Multi-hop Relay Networks

abstract:
  We study a pricing game in multi-hop relay networks where nodes price their
services and route their traffic selfishly and strategically. In this game,
each node (1) announces pricing functions which specify the payments it demands
from its respective customers depending on the amount of traffic they route to
it and (2) allocates the total traffic it receives to its service providers.
The profit of a node is the difference between the revenue earned from
servicing others and the cost of using others' services. We show that the
socially optimal routing of such a game can always be induced by an equilibrium
where no node can increase its profit by unilaterally changing its pricing
functions or routing decision. On the other hand, there may also exist
inefficient equilibria. We characterize the loss of efficiency by deriving the
price of anarchy at inefficient equilibria. We show that the price of anarchy
is finite for oligopolies with concave marginal cost functions, while it is
infinite for general topologies and cost functions.


title: Bounding surface actions on hyperbolic spaces

abstract:
  We give a diameter bound for fundamental domains for isometric actions of the
fundamental group of a closed hyperbolic surface on a delta-hyperbolic space,
where the bound depends on the hyperbolicity constant delta, the genus of the
surface, and the injectivity radius of the action, which we assume to be
strictly positive.


title: Finding Almost Squares III

abstract:
  An almost square of type 2 is an integer $n$ that can be factored in two
different ways as $n = a_1 b_1 = a_2 b_2$ with $a_1$, $a_2$, $b_1$, $b_2
\approx \sqrt{n}$. In this paper, we shall improve upon previous result on
short intervals containing an almost square of type 2. This leads to an inquiry
of finding a short interval around $x$ that contains an integer divisible by
some integer in $[x^c, 2 x^c]$ with $0 < c < 1$.


title:
Entropy Functionals, Sobolev Inequalities and kappa-Noncollapsing
  Estimates along the Ricci Flow

abstract:
  In this survey we review Hamilton's entropy and Perelman's entropy, and
provide motivations for these concepts. Then we review recent results on the
logarithmic Sobolev inequality, the Sobolev inequalities and
kappa-noncollapsing estimates along the Ricci flow, including the Ricci flow
with surgeries.


title:
The WIYN Open Cluster Study Photometric Binary Survey: Initial Findings
  for NGC 188

abstract:
  The WIYN open cluster study (WOCS) has been working to yield precise
magnitudes in the Johnson-Kron-Cousins UBVRI system for all stars in the field
of a selection of ``prototypical'' open clusters. Additionally, WOCS is using
radial velocities to obtain orbit solutions for all cluster binary stars with
periods of less than 1000 days. Recently, WOCS is being expanded to include the
near-infrared JHK_s (deep ground-based plus 2MASS) and mid-infrared ([3.6],
[4.5], [5.8], [8.0]) photometry from Spitzer/IRAC observations. This
multi-wavelength data (0.3--8.0 microns) allows us photometrically to identify
binaries, with mass ratios from 1.0--0.3, across a wide range of primary
masses. The spectral energy distribution (SED) fitter by Robitaille et al.
(2007) is used to fit the fluxes of 10--12 bands, converted from the observed
magnitudes, to Kurucz stellar models. Using this photometric technique, we find
that NGC 188 has a binary fraction of 36--49% and provide a star-by-star
comparison to the WOCS radial velocity-based binary study.


title: Anisotropic step stiffness from a kinetic model of epitaxial growth

abstract:
  Starting from a detailed model for the kinetics of a step edge or island
boundary, we derive a Gibbs-Thomson type formula and the associated step
stiffness as a function of the step edge orientation angle, $theta$. Basic
ingredients of the model are: (i) the diffusion of point defects (``adatoms'')
on terraces and along step edges; (ii) the convection of kinks along step
edges; and (iii) constitutive laws that relate adatom fluxes, sources for
kinks, and the kink velocity with densities via a mean-field approach. This
model has a kinetic (nonequilibrium) steady-state solution that corresponds to
epitaxial growth through step flow. The step stiffness, $\tbe(\theta)$, is
determined via perturbations of the kinetic steady state for small edge Peclet
number, P, which is the ratio of the deposition to the diffusive flux along a
step edge. In particular, $\tbe$ is found to satisfy $\tbe =O(\theta^{-1})$ for
$O(P^{1/3}) <\theta \ll 1$, which is in agreement with independent,
equilibrium-based calculations.


title: Does the complex deformation of the Riemann equation exhibit shocks?

abstract:
  The Riemann equation $u_t+uu_x=0$, which describes a one-dimensional
accelerationless perfect fluid, possesses solutions that typically develop
shocks in a finite time. This equation is $\cP\cT$ symmetric. A one-parameter
$\cP\cT$-invariant complex deformation of this equation,
$u_t-iu(iu_x)^\epsilon= 0$ ($\epsilon$ real), is solved exactly using the
method of characteristic strips, and it is shown that for real initial
conditions, shocks cannot develop unless $\epsilon$ is an odd integer.

categories: hep-th cond-mat.other math-ph math.MP nlin.PS physics.flu-dyn quant-ph


title:
A Photometric Survey for Variables and Transits in the Field of Praesepe
  with KELT

abstract:
  The Kilodegree Extremely Little Telescope (KELT) project is a small aperture,
wide-angle search for planetary transits of solar-type stars. In this paper, we
present the results of a commissioning campaign with the KELT telescope to
observe the open cluster Praesepe for 34 nights in early 2005. Lightcurves were
obtained for 69,337 stars, out of which we identify 58 long period variables
and 152 periodic variables. Sixteen of these are previously known as variable,
yielding 194 newly discovered variable stars for which we provide properties
and lightcurves. We also searched for planetary-like transits, finding four
transit candidates. Follow-up observations indicate that two of the candidates
are astrophysical false positives, with two candidates remaining as potential
planetary transits.


title: Polynomial Approximation and $\omega^r_\phi (f,t)$ Twenty Years Later

abstract:
  About twenty years ago the measure of smoothness $\omega ^r_\phi (f,t)$ was
introduced and related to the rate of polynomial approximation. In this article
we survey developments about this and related concepts since that time.


title: Convex-compactness and its applications

abstract:
  The concept of convex compactness, weaker than the classical notion of
compactness, is introduced and discussed. It is shown that a large class of
convex subsets of topological vector spaces shares this property and that is
can be used in lieu of compactness in a variety of cases. Specifically, we
establish convex compactness for certain familiar classes of subsets of the set
of positive random variables under the topology induced by convergence in
probability.
  Two applications in infinite-dimensional optimization - attainment of infima
and a version of the Minimax theorem - are given. Moreover, a new fixed-point
theorem of the Knaster-Kuratowski-Mazurkiewicz-type is derived and used to
prove a general version of the Walrasian excess-demand theorem.


title: Bubble Raft Model for a Paraboloidal Crystal

abstract:
  We investigate crystalline order on a two-dimensional paraboloid of
revolution by assembling a single layer of millimeter-sized soap bubbles on the
surface of a rotating liquid, thus extending the classic work of Bragg and Nye
on planar soap bubble rafts. Topological constraints require crystalline
configurations to contain a certain minimum number of topological defects such
as disclinations or grain boundary scars whose structure is analyzed as a
function of the aspect ratio of the paraboloid. We find the defect structure to
agree with theoretical predictions and propose a mechanism for scar nucleation
in the presence of large Gaussian curvature.


title: Radial flow afterburner for event generators and the baryon puzzle

abstract:
  A simple afterburner including radial flow to the randomized transverse
momentum obtained from event generators, Pythia and Hijing, has been
implemented to calculate the $p/\pi$ ratios and compare them with available
data. A coherent trend of qualitative agreement has been obtained in $pp$
collisions and in $Au+Au$ for various centralities. Those results indicate that
the radial flow does play an important role in the so called baryon puzzle
anomaly.


title: VCC 2062: an old Tidal Dwarf Galaxy in the Virgo Cluster?

abstract:
  Numerical simulations predict the existence of old Tidal Dwarf Galaxies
(TDGs) that would have survived several Gyr after the collision lying at their
origin. Such survivors, which would by now have become independent relaxed
galaxies, would be ideal laboratories, if nearby enough, to tackle a number of
topical issues, including the distribution of Dark Matter in and around
galaxies. However finding old dwarf galaxies with a confirmed tidal origin is
an observational challenge. A dwarf galaxy in the Virgo Cluster, VCC 2062,
exhibits several unusual properties that are typical of a galaxy made out of
recycled material. We discuss whether it may indeed be a TDG. We analysed
multi-wavelength observations of VCC 2062, including an IRAM CO map, an optical
spectrum of its HII regions, GALEX ultraviolet and archival broad-band and
narrow-band optical images as well as a VLA HI datacube, originally obtained as
part of the VIVA project. VCC 2062 appears to be the optical, low surface
brightness counterpart of a kinematically detached, rotating condensation that
formed within an HI tail apparently physically linked to the disturbed galaxy
NGC 4694. In contrast to its faint optical luminosity, VCC 2062 is
characterised by strong CO emission and a high oxygen abundance more typical of
spiral disks. Its dynamical mass however, is that of a dwarf galaxy. VCC 2062
was most likely formed within a pre-enriched gaseous structure expelled from a
larger galaxy as a result of a tidal interaction. The natural provider for the
gaseous tail is NGC 4694 or rather a former companion which subsequently has
been accreted by the massive galaxy. According to that scenario, VCC 2062 has
been formed by a past tidal encounter. Since its parent galaxies have most
probably already totally merged, it qualifies as an old TDG.


title:
Incorporating interactive 3-dimensional graphics in astronomy research
  papers

abstract:
  Most research data collections created or used by astronomers are
intrinsically multi-dimensional. In contrast, all visual representations of
data presented within research papers are exclusively 2-dimensional. We present
a resolution of this dichotomy that uses a novel technique for embedding
3-dimensional (3-d) visualisations of astronomy data sets in electronic-format
research papers. Our technique uses the latest Adobe Portable Document Format
extensions together with a new version of the S2PLOT programming library. The
3-d models can be easily rotated and explored by the reader and, in some cases,
modified. We demonstrate example applications of this technique including: 3-d
figures exhibiting subtle structure in redshift catalogues, colour-magnitude
diagrams and halo merger trees; 3-d isosurface and volume renderings of
cosmological simulations; and 3-d models of instructional diagrams and
instrument designs.


title:
Localization and delocalization in the quantum kicked prime number
  rotator

abstract:
  The quantum kicked prime number rotator (QKPR) is defined as the rotator
whose energy levels are prime numbers. The long time behavior is decided by the
kick period $\tau$ and kick strength $k$. When $\frac{\tau}{2\pi}$ is
irrational, QKPR is localized because of the equidistribution theorem. When
$\frac{\tau}{2\pi}$ is rational, QKPR is localized for small $k$, because the
system seems like a generalized kicked dimer model. We argue for rational
$\frac{\tau}{2\pi}$ QKPR delocalizes for large k.


title:
Comment on "Macroscopic violation of special relativity" by Nimtz and
  Stahlhofen [arXiv:0708.0681v1]

abstract:
  A recent paper by G. Nimtz and A. A. Stahlhofen [arXiv:0708.0681v1] makes the
following claims: (1) that the authors have observed a macroscopic violation of
special relativity, (2) that they have demonstrated quantum mechanical behavior
of evanescent modes on a meter-length scale, and (3) that barriers are crossed
in zero time, implying superluminal (faster than light), and indeed, infinite
tunneling velocity. Here I suggest that all these claims are erroneous and are
based on a misinterpretation of a purely classical measurement accurately
described by Maxwell's equations.


title: The NuMI Beam at FNAL and its use for Cross Section Measurements

abstract:
  The Neutrinos at the Main Injector (NuMI) facility at Fermilab began
operations in late 2004. NuMI will deliver an intense muon neutrino beam of
variable energy (2-20 GeV). Several aspects of the design and results from runs
of the MINOS experiment are reviewed. I also discuss technique to measure
directly the neutrino flux using a muon flux system at the end of the NuMI
line.


title:
Impacts of real-time data collection on introductory algebra-based
  physics

abstract:
  Including real-time data collection technology is a common practice to
upgrade physics labs, and the assumption is such technology improves student
learning, yet little has been done to demonstrate the effects of technology.
Specific activities have been shown to be enhanced by technology, but the
effects on the class as a whole has been left unexplored. This paper
investigates the effects of technology on two algebra based introductory
physics classes. In this paper, we use FCI, MPEX, surveys, and ethnographies to
document the improvement in learning as real-time data collection technology is
incorporated into a modeling physics class. The two classes examined differed
only in the inclusion of technology. The results found were significant.
Students in the class with high technology were found to have learned more than
students in the class with no technology. This paper explores the gains in
learning and relates them directly to the addition of technology.


title: Formation Scenario for Wide and Close Binary Systems

abstract:
  Fragmentation and binary formation processes are studied using
three-dimensional resistive MHD nested grid simulations. Starting with a
Bonnor-Ebert isothermal cloud rotating in a uniform magnetic field, we
calculate the cloud evolution from the molecular cloud core (n=10^4 cm^-3) to
the stellar core (n \simeq 10^22 cm^-3). We calculated 147 models with
different initial magnetic, rotational, and thermal energies, and the
amplitudes of the non-axisymmetric perturbation. In a collapsing cloud,
fragmentation is mainly controlled by the initial ratio of the rotational to
the magnetic energy, regardless of the initial thermal energy and amplitude of
the non-axisymmetric perturbation. When the clouds have large rotational
energies in relation to magnetic energies, fragmentation occurs in the
low-density evolution phase (10^12 cm^-3 < n < 10^15 cm^-3) with separations of
3-300 AU. Fragments that appeared in this phase are expected to evolve into
wide binary systems. On the other hand, fragmentation does not occur in the
low-density evolution phase, when initial clouds have large magnetic energies
in relation to the rotational energies. In these clouds, fragmentation only
occurs in the high-density evolution phase (n > 10^17 cm^-3) after the clouds
experience significant reduction of the magnetic field owing to Ohmic
dissipation in the period of 10^12 cm^-3 < n < 10^15 cm^-3. Fragments appearing
in this phase have separations of < 0.3 AU, and are expected to evolve into
close binary systems. As a result, we found two typical fragmentation epochs,
which cause different stellar separations. Although these typical separations
are disturbed in the subsequent gas accretion phase, we might be able to
observe two peaks of binary separations in extremely young stellar groups.


title: Transverse Observables and Mass Determination at Hadron Colliders

abstract:
  I consider the two-body decay of a particle at a hadron collider into a
visible and an invisible particle, generalizing $W \to e \nu$, where the masses
of the decaying particle and the invisible decay particle are, {\em a priori},
unknown. I prove that the transverse mass, when maximized over possible
kinematic configurations, can be used to determine both of the unknown masses.
I argue that the proof can be generalized to cover cases such as decays of
pair-produced superpartners to the lightest, stable superpartner at the Large
Hadron Collider.


title:
Vacuum and semiclassical gravity: a difficulty and its bewildering
  significance

abstract:
  We review a long-standing difficulty in some semiclassical models of vacuum
and vacuum decay. Surprisingly enough these models, careless of their
transparent formulation, are affected by, both, technical and conceptual
issues. After proving some general results that are relevant for, both, the
Euclidean and Lorentzian sectors of their dynamics, we briefly highlight their
importance in connection with the issues discussed before, arguing that their
solution might be interesting in our quest for quantum gravity.


title:
Threshold scans in diffractive W pair production via QED processes at
  the LHC

abstract:
  We propose a new set of measurements which can be performed at the LHC using
roman pot detectors. This new method is based on exploiting excitation curves
to measure kinematical properties of produced particles. We illustrate it in
the case of central diffractive W pair production.


title: Instability of agegraphic dark energy models

abstract:
  We investigate the agegraphic dark energy models which were recently proposed
to explain the dark energy-dominated universe. For this purpose, we calculate
their equation of states and squared speeds of sound. We find that the squared
speed for agegraphic dark energy is always negative. This means that the
perfect fluid for agegraphic dark energy is classically unstable. Furthermore,
it is shown that the new agegraphic dark energy model could describe the matter
(radiation)-dominated universe in the far past only when the parameter $n$ is
chosen to be $n>n_c$, where the critical values are determined to be
$n_c=2.6878(2.5137752)$ numerically. It seems that the new agegraphic dark
energy model is no better than the holographic dark energy model for the
description of the dark energy-dominated universe, even though it resolves the
causality problem.


title: Efficient generation of an isolated single-cycle attosecond pulse

abstract:
  A new method for efficiently generating an isolated single-cycle attosecond
pulse is proposed. It is shown that the ultraviolet (UV) attosecond pulse can
be utilized as a robust tool to control the dynamics of electron wave packets
(EWPs). By adding a UV attosecond pulse to an infrared (IR) few-cycle pulse at
a proper time, only one return of the EWP to the parent ion is selected to
effectively contribute to the harmonics, then an isolated two-cycle 130-as
pulse with a bandwidth of 45 eV is obtained. After complementing the chirp, an
isolated single-cycle attosecond pulse with a duration less than 100 as seems
achievable. In addition, the contribution of the quantum trajectories can be
selected by adjusting the delay between the IR and UV fields. Using this
method, the harmonic and attosecond pulse yields are efficiently enhanced in
contrast to the scheme [G. Sansone {\it et al.}, Science {\bf314}, 443 (2006)]
using a few-cycle IR pulse in combination with the polarization gating
technique.


title:
Thermodynamical properties of dark energy with the equation of state $%
  \omega =\omega_{0}+\omega_{1}z$

abstract:
  The thermodynamical properties of dark energy are usually investigated with
the equation of state $\omega =\omega_{0}+\omega_{1}z$. Recent observations
show that our universe is accelerating, and the apparent horizon and the event
horizon vary with redshift $z$. When definitions of the temperature and entropy
of a black hole are used to the two horizons of the universe, we examine the
thermodynamical properties of the universe which is enveloped by the apparent
horizon and the event horizon respectively. We show that the first and the
second laws of thermodynamics inside the apparent horizon in any redshift are
satisfied, while they are broken down inside the event horizon in some
redshift. Therefore, the apparent horizon for the universe may be the boundary
of thermodynamical equilibrium for the universe like the event horizon for a
black hole.


title:
Low energy H+CO scattering revisited: CO rotational excitation with new
  potential surfaces

abstract:
  A recent modeling study of brightness ratios for CO rotational transitions in
gas typical of the diffuse ISM by Liszt found the role of H collisions to be
more important than previously assumed. This conclusion was based on quantum
scattering calculations using the so-called WKS potential energy surface (PES)
which reported a large cross section for the important 0->1 rotational
transition. New close-coupling (CC) rigid-rotor calculations for CO(v=0,J=0)
excitation by H are performed on four different PESs. Two of the PESs are
obtained in this work using state-of-the-art quantum chemistry techniques at
the CCSD(T) and MRCI levels of theory. Cross sections for the J=0->1, as well
as other odd Delta J, transitions are significantly suppressed compared to even
Delta J transitions in thermal energy CC calculations using the CCSD(T) and
MRCI surfaces. This is consistent with a expected even Delta J propensity and
in contrast to CC calculations using the earlier WKS PES which predict a
dominating 0->1 transition. The current results suggest that the original
astrophysical assumption that excitation of CO by H_2 dominates the kinetics of
CO in diffuse ISM gas is likely to remain valid.


title: Spin squeezing and maximal-squeezing time

abstract:
  Spin squeezing of a nonlinear interaction model with Josephson-like coupling
is studied to obtain time scale of maximal squeezing. Based upon two exactly
solvable cases for two and three particles, we find that the maximal-squeezing
time depends on the level spacing between the ground state and its next
neighbor eigenstate.


title: Super-resolution and non-diffraction longitudinal polarized beam

abstract:
  A method is presented for generation of a subwavelength (0.43 lambda)
longitudinally polarized beam, which propagates without divergence over lengths
of about 4 lambda in free space. This is achieved by controlling the amplitude,
phase and polarization property of the Bessel-Gaussian field on the aperture of
a high numerical aperture focusing lens.


title: Single Atoms on an Optical Nanofiber

abstract:
  We show that single-atoms can be trapped on the surface of a
subwavelength-diameter silica-fiber, an optical nanofiber, without any external
field, and that single photons spontaneously emitted from the atoms can be
readily detected through the single guided-mode of the nanofiber. A key point
of the work is our finding that atom trapping sites are created on the
nanofiber surface by irradiating the atom cloud around the nanofiber with a
violet laser radiation.


title:
A solution to the hierarchy problem from an almost decoupled hidden
  sector within a classically scale invariant theory

abstract:
  If scale invariance is a classical symmetry then both the Planck scale and
the weak scale should emerge as quantum effects. We show that this can be
realized in simple scale invariant theories with a hidden sector. The
weak/Planck scale hierarchy emerges in the (technically natural) limit where
the hidden sector decouples from the ordinary sector. The weak scale is
protected from quadratic divergences because of classical scale invariance, so
there is no hierarchy problem.


title:
Instabilities of relativistic mean field models and the role of
  nonlinear terms

abstract:
  The instability of nuclear matter due to particle-hole excitation modes has
been studied in the frame-work of several relativistic mean field (RMF) models.
It is found that both the longitudinal and the transversal modes depend
sensitively on the parameter sets used. The important impact of the vector and
vector-scalar nonlinear terms on the stability of both modes is demonstrated.
Our finding corroborates the result of previous studies, namely that certain
RMF models cannot be used in high density applications. However, we show that
for certain parameter sets of RMF models this shortcoming can be alleviated by
adding these nonlinear terms.


title:
Random Walk Access Times on Partially-Disordered Complex Networks: an
  Effective Medium Theory

abstract:
  An analytic effective medium theory is constructed to study the mean access
times for random walks on hybrid disordered structures formed by embedding
complex networks into regular lattices, considering transition rates $F$ that
are different for steps across lattice bonds from the rates $f$ across network
shortcuts. The theory is developed for structures with arbitrary shortcut
distributions and applied to a class of partially-disordered traversal enhanced
networks in which shortcuts of fixed length are distributed randomly with
finite probability. Numerical simulations are found to be in excellent
agreement with predictions of the effective medium theory on all aspects
addressed by the latter. Access times for random walks on these partially
disordered structures are compared to those on small-world networks, which on
average appear to provide the most effective means of decreasing access times
uniformly across the network.


title: Considerations for an Ac Dipole for the LHC

abstract:
  Following successful experience at the BNL AGS, FNAL Tevatron, and CERN SPS,
an AC Dipole will be adopted at the LHC for rapid measurements of ring optics.
This paper describes some of the parameters of the AC dipole for the LHC,
scaling from performance of the FNAL and BNL devices.


title: Slowly Rotating Dilaton Black hole In Anti-de Sitter Spacetime

abstract:
  Rotating dilaton black hole solution for asymptotically anti-de Sitter
spacetime are obtained in the small angular momentum limit with an appropriate
combination of three Liouville-type dilaton potentials. The angular momentum,
magnetic dipole moment and the gyromagnetic ratio of such a black hole are
determined for arbitrary values of the dilaton-electromagnetic coupling
parameter.


title:
Different representations of Euclidean geometry and their application to
  the space-time geometry

abstract:
  Three different representation of the proper Euclidean geometry are
considered. They differ in the number of basic elements, from which the
geometrical objects are constructed. In E-representation there are three basic
elements (point, segment, angle) and no additional structures. V-representation
contains two basic elements (point, vector) and additional structure: linear
vector space. In sigma-representation there is only one basic element and
additional structure: world function \sigma =\rho^{2}/2, where \rho is the
distance. The concept of distance appears in all representations. However, as a
structure, determining the geometry, the distance appears only in the
sigma-representation. The sigma-representation is most appropriate for
modification of the proper Euclidean geometry. Practically any modification of
the proper Euclidean geometry turns it into multivariant geometry, where there
are many vectors Q_0Q_1, Q_0Q_1^{\prime},..., which are equal to the vector
P_0P_1, but they are not equal between themselves, in general. Concept of
multivariance is very important in application to the space-time geometry. The
real space-time geometry is multivariant. Multivariance of the space-time
geometry is responsible for quantum effects.


title:
Evolution of the spin Hall effect in Pt nanowires: Size and temperature
  effects

abstract:
  We have studied the evolution of the Spin Hall Effect in the regime where the
material size responsible for the spin accumulation is either smaller or larger
than the spin diffusion length. Lateral spin valve structures with Pt
insertions were successfully used to measure the spin absorption efficiency as
well as the spin accumulation in Pt induced through the spin Hall effect. Under
a constant applied current the results show a decrease of the spin accumulation
signal is more pronounced as the Pt thickness exceeds the spin diffusion
length. This implies that the spin accumulation originates from bulk scattering
inside the Pt wire and the spin diffusion length limits the SHE. We have also
analyzed the temperature variation of the spin hall conductivity to identify
the dominant scattering mechanism.


title: Tkachenko modes in a superfluid Fermi gas at unitarity

abstract:
  We calculate the frequencies of the Tkachenko oscillations of a vortex
lattice in a harmonically trapped superfluid Fermi gas. We use the
elasto-hydrodynamic theory by properly accounting for the elastic constants,
the Thomas-Fermi density profile of the atomic cloud, and the boundary
conditions. Thanks to the Fermi pressure, which is responsible for larger cloud
radii with respect to the case of dilute Bose-Einstein condensed gases, large
vortex lattices are achievable in the unitary limit of infinite scattering
length, even at relatively small angular velocities. This opens the possibility
of experimentally observing vortex oscillations in the regime where the
dispersion relation approaches the Tkachenko law for incompressible fluids and
the mode frequency is almost comparable to the trapping frequencies.


title:
Einstein e il Rinnovamento delle Scienze (Einstein and the Renewal of
  Science)

abstract:
  As it is well-known, the year 2005 has been the centenary of the "annus
mirabilis" (1905) during which Albert Einstein published four fundamental
papers of his. But already in 1979, for the centenary of Einstein's birth, the
world celebrated his monumantal work. In Italy too, there appeared scientific
books, and many semi-popularization (or popularization) articles. The present
paper represents a talk delivered in Italian, at the invitation of the Nobel
Foundation (Sanremo, IM; Italy), in time for its publication in 1979. This
article has been however reprinted, much more recently, in 2002, by the "Centro
DIEA", Faculty of Engineering, University of Bologna, Bologna, Italy [and its
source-file, in html, has been prepared with DIEA's collaboration]. We present
here a description of the human, philosophycal and scientific background,
starting from which Einstein produced his amazing results: Indeed, we try to
show why Einstein's writings today are still so important not only for pure
physics (and technology!), but also for our epistemological understanding of
the procedures followed by science, and by our own mind, in their development,
as well as for our philosophical views about the world we live in; without
forgetting the teachings that come (or should come) from Einstein's life and
claims for modern pedagogy.


title: Stability of the rotating SU(3) Skyrmion

abstract:
  The profile functions of the SU(3) Skyrme soliton are investigated for the
octet, decuplet, and antidecuplet baryons by the mean field approach. In this
approach, the profile functions are affected by the spatial rotation, the
flavor rotation, and the flavor symmetry breaking. The solitons are stable only
in the restricted areas of the parameter space for each multiplet. When the
flavor symmetry breaking is large, the area for the antidecuplet is narrow
compared to those for the octet and decuplet. The parameters are determined by
the baryon mass spectrum, and the deformation of the soliton has sizable
effects on the masses.


title: Supervised Machine Learning with a Novel Kernel Density Estimator

abstract:
  In recent years, kernel density estimation has been exploited by computer
scientists to model machine learning problems. The kernel density estimation
based approaches are of interest due to the low time complexity of either O(n)
or O(n*log(n)) for constructing a classifier, where n is the number of sampling
instances. Concerning design of kernel density estimators, one essential issue
is how fast the pointwise mean square error (MSE) and/or the integrated mean
square error (IMSE) diminish as the number of sampling instances increases. In
this article, it is shown that with the proposed kernel function it is feasible
to make the pointwise MSE of the density estimator converge at O(n^-2/3)
regardless of the dimension of the vector space, provided that the probability
density function at the point of interest meets certain conditions.


title: Unbounded-Error Classical and Quantum Communication Complexity

abstract:
  Since the seminal work of Paturi and Simon \cite[FOCS'84 & JCSS'86]{PS86},
the unbounded-error classical communication complexity of a Boolean function
has been studied based on the arrangement of points and hyperplanes. Recently,
\cite[ICALP'07]{INRY07} found that the unbounded-error {\em quantum}
communication complexity in the {\em one-way communication} model can also be
investigated using the arrangement, and showed that it is exactly (without a
difference of even one qubit) half of the classical one-way communication
complexity. In this paper, we extend the arrangement argument to the {\em
two-way} and {\em simultaneous message passing} (SMP) models. As a result, we
show similarly tight bounds of the unbounded-error two-way/one-way/SMP
quantum/classical communication complexities for {\em any} partial/total
Boolean function, implying that all of them are equivalent up to a
multiplicative constant of four. Moreover, the arrangement argument is also
used to show that the gap between {\em weakly} unbounded-error quantum and
classical communication complexities is at most a factor of three.


title:
Biomimetic Space-Variant Sampling in a Vision Prosthesis Improves the
  User's Skill in a Localization Task

abstract:
  In this experiment, we test the hypothesis of whether a 'retina-like' space
variant sampling pattern can improve the efficiency of a visual prosthesis.
Subjects wearing a visuo-auditory substitution system were tested for their
ability to point at visual targets. The test group (space-variant sampling),
performed significantly better than the control group (uniform sampling). The
pointing accuracy was enhanced, as was the speed to find the target.
Surprisingly, the time spanned to complete the training was also reduced,
suggesting that this space-variant sampling scheme facilitates the mastering of
sensorimotor contingencies.