title:
Finite-size scaling of string order parameters characterizing the
  Haldane phase

abstract:
  We have developed a numerical procedure to clarify the critical behavior near
a quantum phase transition by analyzing a multi-point correlation function
characterizing the ground state. This work presents a successful application of
this procedure to the string order parameter of the S = 1 XXZ chain with
uniaxial single-ion anisotropy. The finite-size string correlation function is
estimated by the density matrix renormalization group method. We focus on the
gradient of the inversedsystem- size dependence of the correlation function on
a logarithmic plot. This quantity shows that the finite-size scaling
sensitively changes at the critical point. The behavior of the gradient with
increasing system size is divergent, stable at a finite value, or rapidly
decreases to zero when the system is in the disordered phase, at the critical
point, or in the ordered phase, respectively. The analysis of the finite-size
string correlation functions allows precise determination of the boundary of
the Haldane phase and estimation of the critical exponent of the correlation
length. Our estimates of the transition point and the critical exponents, which
are determined only by the ground-state quantities, are consistent with results
obtained from the analysis of the energy-level structure. Our analysis requires
only the correlation functions of several finite sizes under the same condition
as a candidate for the long-range order. The quantity is treated in the same
manner irrespective of the kind of elements which destroy the order concerned.
This work will assist in the development of a method to directly observe
quantum phase transitions.


title:
Spin susceptibility, phase diagram, and quantum criticality in the
  electron-doped high Tc Superconductor Ba[Fe(1-x)Co(x)]2As2

abstract:
  We report a systematic investigation of Ba[Fe(1-x)Co(x)]2As2 based on
transport and 75-As NMR measurements, and establish the electronic phase
diagram. We demonstrate that doping progressively suppresses the uniform spin
susceptibility and low frequency spin fluctuations. The optimum superconducting
phase emerges at x_c~0.08 when the tendency toward spin ordering completely
diminishes. Our findings point toward the presence of a quantum critical point
near x_c between the SDW (spin density wave) and superconducting phases.


title: Airport Gate Assignment: New Model and Implementation

abstract:
  Airport gate assignment is of great importance in airport operations. In this
paper, we study the Airport Gate Assignment Problem (AGAP), propose a new model
and implement the model with Optimization Programming language (OPL). With the
objective to minimize the number of conflicts of any two adjacent aircrafts
assigned to the same gate, we build a mathematical model with logical
constraints and the binary constraints, which can provide an efficient
evaluation criterion for the Airlines to estimate the current gate assignment.
To illustrate the feasibility of the model we construct experiments with the
data obtained from Continental Airlines, Houston Gorge Bush Intercontinental
Airport IAH, which indicate that our model is both energetic and effective.
Moreover, we interpret experimental results, which further demonstrate that our
proposed model can provide a powerful tool for airline companies to estimate
the efficiency of their current work of gate assignment.


title: Alpha decay chains from superheavy nuclei

abstract:
  Magic islands for extra-stable nuclei in the midst of the sea of
fission-instability were predicted to be around Z=114, 124 or, 126 with N=184,
and Z=120, with N=172. Whether these fission-survived superheavy nuclei with
high Z and N would live long enough for detection or, undergo alpha-decay in a
very short time remains an open question. Alpha-decay half lives of nuclei with
130 < Z < 100 have been calculated in a WKB framework using density-dependent
M3Y interaction with Q-values from different mass formulae. The results are in
excellent agreement with the experimental data. Fission survived Sg nuclei with
Z=106, N=162 is predicted to have the highest alpha-decay half life ~ 3.2 hrs
in the Z=106-108, N=160-164 region called, small island/peninsula. Superheavy
nuclei with Z > 118 are found to have alpha-decay half lives of the order of
microseconds or, less.


title:
Stationary Configurations Imply Shift Symmetry: No Bondi Accretion for
  Quintessence / k-Essence

abstract:
  In this paper we show that, for general scalar fields, stationary
configurations are possible for shift symmetric theories only. This symmetry
with respect to constant translations in field space should either be manifest
in the original field variables or reveal itself after an appropriate field
redefinition. In particular this result implies that neither k-Essence nor
Quintessence can have exact steady state / Bondi accretion onto Black Holes. We
also discuss the role of field redefinitions in k-Essence theories. Here we
study the transformation properties of observables and other variables in
k-Essence and emphasize which of them are covariant under field redefinitions.
Finally we find that stationary field configurations are necessarily linear in
Killing time, provided that shift symmetry is realized in terms of these field
variables.


title: Entropy of a quantum error correction code

abstract:
  We define and investigate a notion of entropy for quantum error correcting
codes. The entropy of a code for a given quantum channel has a number of
equivalent realisations, such as through the coefficients associated with the
Knill-Laflamme conditions and the entropy exchange computed with respect to any
initial state supported on the code. In general the entropy of a code can be
viewed as a measure of how close it is to the minimal entropy case, which is
given by unitarily correctable codes (including decoherence-free subspaces), or
the maximal entropy case, which from dynamical Choi matrix considerations
corresponds to non-degenerate codes. We consider several examples, including a
detailed analysis in the case of binary unitary channels, and we discuss an
extension of the entropy to operator quantum error correcting subsystem codes.


title: Black Hole Evaporation as a Nonequilibrium Process

abstract:
  When a black hole evaporates, there arises a net energy flow from the black
hole into its outside environment due to the Hawking radiation and the energy
accretion onto black hole. Exactly speaking, due to the net energy flow, the
black hole evaporation is a nonequilibrium process. To study details of
evaporation process, nonequilibrium effects of the net energy flow should be
taken into account. In this article we simplify the situation so that the
Hawking radiation consists of non-self-interacting massless matter fields and
also the energy accretion onto the black hole consists of the same fields. Then
we find that the nonequilibrium nature of black hole evaporation is described
by a nonequilibrium state of that field, and we formulate nonequilibrium
thermodynamics of non-self-interacting massless fields. By applying it to black
hole evaporation, followings are shown: (1) Nonequilibrium effects of the
energy flow tends to accelerate the black hole evaporation, and, consequently,
a specific nonequilibrium phenomenon of semi-classical black hole evaporation
is suggested. Furthermore a suggestion about the end state of quantum size
black hole evaporation is proposed in the context of information loss paradox.
(2) Negative heat capacity of black hole is the physical essence of the
generalized second law of black hole thermodynamics, and self-entropy
production inside the matter around black hole is not necessary to ensure the
generalized second law. Furthermore a lower bound for total entropy at the end
of black hole evaporation is given. A relation of the lower bound with the
so-called covariant entropy bound conjecture is interesting but left as an open
issue.


title: Periodic solutions of a resistive model for nonlocal Josephson dynamics

abstract:
  A novel method is developed for constructing periodic solutions of a model
equation describing nonlocal Josephson electrodynamics. This method consists of
reducing the equation to a system of linear ordinary differential equations
through a sequence of nonlinear transformations. The periodic solutions are
then obtained by a standard procedure which are represented in terms of
trigonometric functions. It is found that the large time asymptotic of the
solution exhibits a steady profile which does not depend on initial conditions.


title:
On the Origin of the 2DEG Carrier Density at the LaAlO$_3$/SrTiO$_3$
  Interface

abstract:
  Transport measurements of the two-dimensional electron gas (2DEG) at the
LaAlO$_3$/SrTiO$_3$ interface have found a density of carriers much lower than
expected from the "polar catastrophe" arguments. From a detail
density-functional study, we suggest how this discrepancy may be reconciled. We
find that electrons occupy multiple subbands at the interface leading to a rich
array of transport properties. Some electrons are confined to a single
interfacial layer and susceptible to localization, while others with small
masses and extended over several layers are expected to contribute to
transport.


title:
Direct observation of Hardy's paradox by joint weak measurement with an
  entangled photon pair

abstract:
  We implemented a joint weak measurement of the trajectories of two photons in
a photonic version of Hardy's experiment. The joint weak measurement has been
performed via an entangled meter state in polarization degrees of freedom of
the two photons. Unlike Hardy's original argument in which the contradiction is
inferred by retrodiction, our experiment reveals its paradoxical nature as
preposterous values actually read out from the meter. Such a direct observation
of a paradox will give us a new insight into the spooky action of quantum
mechanics.


title:
Ground-State Properties of a Heisenberg Spin Glass Model with a Hybrid
  Genetic Algorithm

abstract:
  We developed a genetic algorithm (GA) in the Heisenberg model that combines a
triadic crossover and a parameter-free genetic algorithm. Using the algorithm,
we examined the ground-state stiffness of the $\pm J$ Heisenberg model in three
dimensions up to a moderate size range. Results showed the stiffness constant
of $\theta = 0$ in the periodic-antiperiodic boundary condition method and that
of $\theta \sim 0.62$ in the open-boundary-twist method. We considered the
origin of the difference in $\theta$ between the two methods and suggested that
both results show the same thing: the ground state of the open system is stable
against a weak perturbation.


title: Predator-Prey Quasi-cycles from a Path Integral Formalism

abstract:
  The existence of beyond mean field quasi-cycle oscillations in a simple
spatial model of predator prey interactions is derived from a path integral
formalism. The results agree substantially with those obtained from analysis of
similar models using system size expansions of the master equation. In all of
these analyses, the discrete nature of predator prey populations and finite
size effects lead to persistent oscillations in time, but spatial patterns fail
to form. The path integral formalism goes beyond mean field theory and provides
a focus on individual realizations of the stochastic time evolution of
population not captured in the standard master equation approach.


title:
On Proximity of 4/7 Solid Phase of 3He Adsorbed on Graphite -Origin of
  Specific-Heat Anomalies in Hole-Doped Density-Ordered Solid-

abstract:
  We theoretically study the stability of the solidified second-layer 3He at
4/7 of the first-layer density adsorbed on graphite, which exhibits quantum
spin liquid. We construct a lattice model for the second-layer 3He by taking
account of density fluctuations on the third layer together by employing the
refined configuration recently found by path integral Monte Carlo simulations.
When holes are doped into the 4/7 solid, within the mean-field approximation,
the density-ordered fluid emerges. The evolution of hole pockets offers a
unified explanation for the measured doping and temperature dependences of
specific-heat anomalies. We argue that differentiation in momentum space is a
key to understanding the physics and accounts for multiscale thermodynamic
anomalies in the mono- and double-layered 3He systems beyond the mean-field
level.


title: Stability Bound for Stationary Phi-mixing and Beta-mixing Processes

abstract:
  Most generalization bounds in learning theory are based on some measure of
the complexity of the hypothesis class used, independently of any algorithm. In
contrast, the notion of algorithmic stability can be used to derive tight
generalization bounds that are tailored to specific learning algorithms by
exploiting their particular properties. However, as in much of learning theory,
existing stability analyses and bounds apply only in the scenario where the
samples are independently and identically distributed. In many machine learning
applications, however, this assumption does not hold. The observations received
by the learning algorithm often have some inherent temporal dependence.
  This paper studies the scenario where the observations are drawn from a
stationary phi-mixing or beta-mixing sequence, a widely adopted assumption in
the study of non-i.i.d. processes that implies a dependence between
observations weakening over time. We prove novel and distinct stability-based
generalization bounds for stationary phi-mixing and beta-mixing sequences.
These bounds strictly generalize the bounds given in the i.i.d. case and apply
to all stable learning algorithms, thereby extending the use of
stability-bounds to non-i.i.d. scenarios.
  We also illustrate the application of our phi-mixing generalization bounds to
general classes of learning algorithms, including Support Vector Regression,
Kernel Ridge Regression, and Support Vector Machines, and many other kernel
regularization-based and relative entropy-based regularization algorithms.
These novel bounds can thus be viewed as the first theoretical basis for the
use of these algorithms in non-i.i.d. scenarios.


title:
Variational Approach to the Chiral Phase Transition in the Linear Sigma
  Model

abstract:
  The chiral phase transition at finite temperature is investigated in the
linear sigma model, which is regarded as a low energy effective theory of QCD
with three momentum cutoff, in the variational method with the Gaussian
approximation in the functional Schroedinger picture. It is shown that the
Goldstone theorem is retained and the meson pair excitations are automatically
included by taking into account the linear response to the external fields. It
is pointed out that the behavior of chiral phase transition depends on the
three-momentum cutoff, which leads to the careful treatment of the problem.


title:
Incipient Separation in Shock Wave Boundary Layer Interactions as
  Induced by Sharp Fin

abstract:
  The incipient separation induced by the shock wave turbulent boundary layer
interaction at the sharp fin is the subject of present study. Existing theories
for the prediction of incipient separation, such as those put forward by McCabe
(1966) and Dou and Deng (1992), can have thus far only predicting the direction
of surface streamline and tend to over-predict the incipient separation
condition based on the Stanbrook's criterion. In this paper, the incipient
separation is firstly predicted with Dou and Deng (1992)'s theory and then
compared with Lu and Settles (1990)' experimental data. The physical mechanism
of the incipient separation as induced by the shock wave/turbulent boundary
layer interactions at sharp fin is explained via the surface flow pattern
analysis. Furthermore, the reason for the observed discrepancy between the
predicted and experimental incipient separation conditions is clarified. It is
found that when the wall limiting streamlines behind the shock wave becomes\
aligning with one ray from the virtual origin as the strength of shock wave
increases, the incipient separation line is formed at which the wall limiting
streamline becomes perpendicular to the local pressure gradient. The formation
of this incipient separation line is the beginning of the separation process.
The effects of Reynolds number and the Mach number on incipient separation are
also discussed. Finally, a correlation for the correction of the incipient
separation angle as predicted by the theory is also given.


title: Mechanism of Tubular Pinch Effect of Dilute Suspension in a Pipe Flow

abstract:
  Experiments have shown that in dilute suspension flow at laminar state
through a circular tube particles migrate towards a concentric annular region
with a mean radius of about 0.6 of the tube radius. This phenomenon is
well-known as the tubular pinch effect, which is still not fully understood. In
this study, the energy gradient method is used to study this phenomenon. It is
found that at low Reynolds number particles will move to the position of
r/R=0.58. Based on the result, the mechanism of this phenomenon is well
explained.


title:
Bulk-edge correspondence in graphene with/without magnetic field: Chiral
  symmetry, Dirac fermions and Edge states

abstract:
  There are two types of edge states in graphene with/without magnetic field.
One is a quantum Hall edge state, which is topologically protected against
small perturbation. The other is a chiral zero mode that is localized near the
boundary with/without magnetic field. The latter is also topological but is
guaranteed to be zero energy by the chiral symmetry, which is also responsible
for massless Dirac like dispersion. Conceptual roles of the edge states are
stressed and reviewed from a view point of the bulk-edge correspondence and the
topological order.


title: High-Speed Collapse of a Hollow Sphere of Type I Matter

abstract:
  In this paper, we study the dynamics of a hollow spherical matter collapsing
with very large initial velocity. The spacetime is initially very similar to
the Vaidya solution, and the deviations from this background are treated
perturbatively. The equations of state for radial pressure $p_{\rm R}=k\rho$
and tangential one $p_{\rm T}=w\rho$ with constant $k$ and $w$ are assumed. We
find for the case of equations of state $k< 1$ and $0<w\leq1$ that the initial
velocity, which is nearly the speed of light, is strongly decelerated. This
result implies that the pressure is essential to the property of singularity
formation in gravitational collapse even for initially nearly light-speed
collapse. By contrast, in cases with the negative tangential pressure, the
present result implies that the central naked singularity similar to that of
the Vaidya spacetime can be formed, even though the radial pressure is
positive, and the weak, strong and dominant energy conditions hold. Especially,
in the case of $w<-(1-k)/4$, the high-speed collapse will produce the spacetime
structure very similar to that of the Vaidya spacetime.


title:
Ultracold-neutron infrastructure for the gravitational spectrometer
  GRANIT

abstract:
  The gravitational spectrometer GRANIT will be set up at the Institut Laue
Langevin. It will profit from the high ultracold neutron density produced by a
dedicated source. A monochromator made of crystals from graphite intercalated
with potassium will provide a neutron beam with 0.89 nm incident on the source.
The source employs superthermal conversion of cold neutrons in superfluid
helium, in a vessel made from BeO ceramics with Be windows. A special
extraction technique has been tested which feeds the spectrometer only with
neutrons with a vertical velocity component v < 20 cm/s, thus keeping the
density in the source high. This new source is expected to provide a density of
up to 800 1/cm3 for the spectrometer.


title: Asymptotics for a free-boundary model in price formation

abstract:
  We study the asymptotics for large time of solutions to a one dimensional
parabolic evolution equation with non-standard measure-valued right hand side,
that involves derivatives of the solution computed at a free boundary point.
The problem is a particular case of a mean-field free boundary model proposed
by Lasry-Lions on price formation and dynamic equilibria.
  The main step in the proof is based on the fact that the free boundary
disappears in the linearized problem, thus can be treated as a perturbation
through semigroup theory. This requires a delicate choice for the function
spaces since higher regularity is needed near the free boundary. We show global
existence for solutions with initial data in a small neighborhood of any
equilibrium point, and exponential decay towards a stationary state. Moreover,
the family of equilibria of the equation is stable, as follows from center
manifold theory.


title: Can the Horowitz-Maldacena proposal be an alternative to the firewall?

abstract:
  Recently, there have been discussions that black hole complementarity is
inconsistent and that the firewall is required to prohibit the observation of
duplicated information. It is thought that if the Horowitz-Maldacena proposal
works as a selection principle, then this may be an alternative to the
firewall. In this paper, we first point out that the Horowitz-Maldacena
proposal seems to help black hole complementarity for charged black holes.
However, if we consider the Hayden-Preskill argument further, which states that
a black hole can function as an information mirror after the information
retention time, then we can show that the Horowitz-Maldaceana proposal cannot
help black hole complementarity. This can be extended to neutral black hole
cases. Therefore, in conclusion, we find that dynamical black holes do not
respect complementarity, even with the Horowitz-Maldacena proposal.


title: Twist Quantization of String and B Field Background

abstract:
  In a previous paper, we investigated the Hopf algebra structure in string
theory and gave a unified formulation of the quantization of the string and the
space-time symmetry. In this paper, this formulation is applied to the case
with a nonzero B-field background, and the twist of the Poincare symmetry is
studied. The Drinfeld twist accompanied by the B-field background gives an
alternative quantization scheme, which requires a new normal ordering. In order
to obtain a physical interpretation of this twisted Hopf algebra structure, we
propose a method to decompose the twist into two successive twists and we give
two different possibilities of decomposition. The first is a natural
decomposition from the viewpoint of the twist quantization, leading to a new
type of twisted Poincare symmetry. The second decomposition reveals the
relation of our formulation to the twisted Poincare symmetry on the Moyal type
noncommutative space.


title: Signals of Statistical Anisotropy in WMAP Foreground-Cleaned Maps

abstract:
  Recently a symmetry-based method to test for statistical isotropy of the
cosmic microwave background was developed. We apply the method to
template-cleaned 3-year and 5-year WMAP-$DA$ maps. We examine a wide range of
angular multipoles from $2 < l < 300$. The analysis detects statistically
signicant signals of anisotropy inconsistent with an isotropic CMB in some of
the foreground cleaned maps. We are unable to resolve whether the anomalies
have a cosmological, local astrophysical or instrumental origin. Assuming the
anisotropy arises due to residual foreground contamination, we estimate the
residual foreground power in the maps. For the W band maps, we also find a
highly improbable degree of isotropy we cannot explain. We speculate that
excess isotropy may be caused by faulty modeling of detector noise.


title: For objective causal inference, design trumps analysis

abstract:
  For obtaining causal inferences that are objective, and therefore have the
best chance of revealing scientific truths, carefully designed and executed
randomized experiments are generally considered to be the gold standard.
Observational studies, in contrast, are generally fraught with problems that
compromise any claim for objectivity of the resulting causal inferences. The
thesis here is that observational studies have to be carefully designed to
approximate randomized experiments, in particular, without examining any final
outcome data. Often a candidate data set will have to be rejected as inadequate
because of lack of data on key covariates, or because of lack of overlap in the
distributions of key covariates between treatment and control groups, often
revealed by careful propensity score analyses. Sometimes the template for the
approximating randomized experiment will have to be altered, and the use of
principal stratification can be helpful in doing this. These issues are
discussed and illustrated using the framework of potential outcomes to define
causal effects, which greatly clarifies critical issues.


title: Electric dipole moments, from e to tau

abstract:
  We derive an upper limit on the electric dipole moment (EDM) of the
tau-lepton, which follows from the precision measurements of the electron EDM.


title:
The Keck Aperture Masking Experiment: spectro-interferometry of 3 Mira
  Variables from 1.1 to 3.8 microns

abstract:
  We present results from a spectro-interferometric study of the Miras o Cet, R
Leo and W Hya obtained with the Keck Aperture Masking Experiment from 1998 Sep
to 2002 Jul. The spectrally dispersed visibility data permit fitting with
circularly symmetric brightness profiles such as a simple uniform disk. The
stellar angular diameter obtained over up to ~ 450 spectral channels spaning
the region 1.1-3.8 microns is presented. Use of a simple uniform disk
brightness model facilitates comparison between epochs and with existing data
and theoretical models. Strong size variations with wavelength were recorded
for all stars, probing zones of H2O, CO, OH, and dust formation. Comparison
with contemporaneous spectra extracted from our data show a strong
anti-correlation between the observed angular diameter and flux. These
variations consolidate the notion of a complex stellar atmosphere consisting of
molecular shells with time-dependent densities and temperatures. Our findings
are compared with existing data and pulsation models. The models were found to
reproduce the functional form of the wavelength vs. angular diameter curve
well, although some departures are noted in the 2.8-3.5 micron range.


title: Anisotropy due to Brans-Dicke Theory

abstract:
  It is well known that the viscous Bianchi type-I metric of the Kasner form is
not able to describe an anisotropic universe, which satisfies the second law of
thermodynamics and the dominant energy condition in Einstein's theory of
gravity. We investigate this problem in Brans-Dicke theory of gravity using the
Bianchi type-I metric with the perfect fluid. We show that it is possible to
have the dominant energy condition and the growth of entropy in this model.
Also we apply this model to explain the anomaly concerning the low quadrupole
amplitude of the angular power spectrum of the temperature anisotropy observed
in WMAP data.


title:
Black and gray spatial optical solitons with Kerr type nonlocal
  nonlinearity

abstract:
  We develop one numerical method to compute black and gray solitons with
Kerr-type nonlocal nonlinearity. As two examples of nonlocal cases, the gray
soliton with exponentially decaying nonlocal response or with Gaussian nonlocal
response are discussed. For such two nonlocal cases, the analytical form of the
tails of nonlocal gray soliton is presented and the analytical relationship for
the maximal transverse velocity of nonlocal gray soliton to the characteristic
nonlocal length is obtained.


title: Random survival forests

abstract:
  We introduce random survival forests, a random forests method for the
analysis of right-censored survival data. New survival splitting rules for
growing survival trees are introduced, as is a new missing data algorithm for
imputing missing data. A conservation-of-events principle for survival forests
is introduced and used to define ensemble mortality, a simple interpretable
measure of mortality that can be used as a predicted outcome. Several
illustrative examples are given, including a case study of the prognostic
implications of body mass for individuals with coronary artery disease.
Computations for all examples were implemented using the freely available
R-software package, randomSurvivalForest.


title:
Phenomenology of $U(1)_{L_\mu - L_\tau}$ charged dark matter at
  PAMELA/FERMI and colliders

abstract:
  Recent data on $e^+/e^-$ and $\bar{p}$ cosmic rays suggest that dark matter
annihilate into the standard model (SM) particles through new leptophilic
interaction. In this paper, we consider a standard model extension with the
gauged $U(1)_{L_\mu - L_\tau}$ group, with a new Dirac fermion charged under
this U(1) as a dark matter. We study the muon $(g-2)_\mu$, thermal relic
density of the cold dark matter, and the collider signatures of this model.
$Z^{'}$ productions at the Tevatron or the LHC could be easily order of
$O(1)-O(10^3)$ fb.


title: Conformal Field Theory on R x S^3 from Quantized Gravity

abstract:
  Conformal algebra on R x S^3 derived from quantized gravitational fields is
examined. The model we study is a renormalizable quantum theory of gravity in
four dimensions described by a combined system of the Weyl action for the
traceless tensor mode and the induced Wess-Zumino action managing
non-perturbative dynamics of the conformal factor in the metric field. It is
shown that the residual diffeomorphism invariance in the radiation^+ gauge is
equal to the conformal symmetry, and the conformal transformation preserving
the gauge-fixing condition that forms a closed algebra quantum mechanically is
given by a combination of naive conformal transformation and a certain
field-dependent gauge transformation. The unitarity issue of gravity is
discussed in the context of conformal field theory. We construct physical
states by solving the conformal invariance condition and calculate their
scaling dimensions. It is shown that the conformal symmetry mixes the
positive-metric and the negative-metric modes and thus the negative-metric mode
does not appear independently as a gauge invariant state at all.


title:
Stationary transport in mesoscopic hybrid structures with contacts to
  superconducting and normal wires. A Green's function approach for
  multiterminal setups

abstract:
  We generalize the representation of the real time Green's functions
introduced by Langreth and Nordlander [Phys. Rev. B 43 2541 (1991)] and Meir
and Wingreen [Phys. Rev. Lett. 68 2512 (1992)] in stationary quantum transport
in order to study problems with hybrid structures containing normal (N) and
superconducting (S) pieces. We illustrate the treatment in a S-N junction under
a stationary bias and investigate in detail the behavior of the equilibrium
currents in a normal ring threaded by a magnetic flux with attached
superconducting wires at equilibrium. We analyze the flux sensitivity of the
Andreev states and we show that their response is equivalent to the one
corresponding to the Cooper pairs with momentum q=0 in an isolated
superconducting ring.


title: The non-locality of n noisy Popescu-Rohrlich boxes

abstract:
  We quantify the amount of non-locality contained in n noisy versions of
so-called Popescu-Rohrlich boxes (PRBs), i.e., bipartite systems violating the
CHSH Bell inequality maximally. Following the approach by Elitzur, Popescu, and
Rohrlich, we measure the amount of non-locality of a system by representing it
as a convex combination of a local behaviour, with maximal possible weight, and
a non-signalling system. We show that the local part of n systems, each of
which approximates a PRB with probability $1-\epsilon$, is of order
$\Theta(\epsilon^{\lceil n/2\rceil})$ in the isotropic, and equal to
$(3\epsilon)^n$ in the maximally biased case.


title:
Elongated Fermi superfluid: absence of critical imbalance enhancement at
  equilibrium

abstract:
  We show that the maximum population imbalance ratio $P_\mathrm{CC}$ for a
two-component Fermi gas near the unitarity limit to condense does not increase
with the trap aspect ratio $\lambda$, by two methods of 1) solving the
Bogoliubov-de Gennes equations with coupling-constant renormalization, and 2)
studying the pairing susceptibility by the real-space self-consistent
$T$-matrix approximation. The deviation of the cloud shape from what is
expected from the trap shape increases but stays minor with increasing
$\lambda$ up to 50. This finding indicates that despite the apparent
discrepancy between the MIT and Rice experiments over the value of
$P_\mathrm{CC}$ and the validity of local density approximation, the
equilibrium state of the system for the aspect ratio in the Rice experiment
should be consistent with that of MIT.


title:
Geometric realizations of curvature models by manifolds with constant
  scalar curvature

abstract:
  We show any Riemannian curvature model can be geometrically realized by a
manifold with constant scalar curvature. We also show that any pseudo-Hermitian
curvature model, para-Hermitian curvature model, hyper-pseudo-Hermitian
curvature model, or hyper-para-Hermitian curvature model can be realized by a
manifold with constant scalar and *-scalar curvature.


title:
Semi-global simulations of the magneto-rotational instability in core
  collapse supernovae

abstract:
  Possible effects of magnetic fields in core collapse supernovae rely on an
efficient amplification of the weak pre-collapse fields. It has been suggested
that the magneto-rotational instability (MRI) leads to rapid field growth.
Although MRI studies exist for accretion discs, the application of their
results to core collapse supernovae is inhibited as the physics of supernova
cores is substantially different from that of accretion discs. We address the
problem of growth and saturation of the MRI by means of semi-global
simulations, which combine elements of global and local simulations by taking
the presence of global background gradients into account and using a local
computational grid. We analyze the dispersion relation of the MRI to identify
different regimes of the instability. This analysis is complemented by
simulations, where we consider a local computational box rotating at
sub-Keplerian velocity, and where we allow for a radial entropy gradient. We
identify six regimes of the MRI depending on the ratio of the entropy and
angular velocity gradient. Our numerical models confirm the instability
criteria and growth rates for all relevant regimes. The MRI grows exponentially
within milliseconds the flow and magnetic field geometries being dominated by
channel flows. The MRI growth ceases once the channels are disrupted by
resistive instabilities (due to finite numerical conductivity), and MHD
turbulence sets in. From an analysis of the growth rates of the resistive
instabilities, we deduce scaling laws for the termination amplitude of the MRI
which agree well with our numerical models. We determine the dependence of the
development of coherent flow structures in the saturated state on the aspect
ratio of the simulation boxes. [abridged]


title: The VVDS-VLA Deep Field - IV: Radio-optical properties

abstract:
  (abridged) We use the 1.4 GHz VIMOS-VLA Deep Survey and the optical VVDS and
the CFHT-LS to compare the properties of radio loud galaxies with respect to
the whole population of optical galaxies. The availability of multiband
photometry and high quality photometric redshifts allows to derive rest frame
colors and radio luminosity functions down to a limit of a B rest-frame
magnitude of M=-20.
  Galaxy properties and luminosity functions (LFs) are estimated up to z~1 for
radio loud and radio quiet early and late type galaxies. Radio loud late type
galaxies are redder than radio quiet objects of the same class and this is an
effect related to the presence of more dust in stronger star forming galaxies.
Moreover, we estimate optical LFs, stellar masses and star formation rate
distributions for radio sources and compare them with those derived for a well
defined control sample, finding that the probability for a galaxy to be a radio
emitter significantly increases at high values of these parameters. Radio loud
early type galaxies show luminosity evolution of their bivariate radio-optical
LF, due to an evolution in the radio-optical ratio. The lack of evolution of
the mass function of radio loud early type galaxies means that no new AGN are
formed at z<1. On the contrary, radio loud late type objects show a strong
evolution, both in luminosity and in density, of the radio LF for z>0.7. This
evolution is the direct effect of the strong optical evolution of this class
and no significant change with redshift of the radio-optical ratio is required.
With the knowledge of the radio-optical ratio and the optical and radio LFs for
late type galaxies, we estimated the star formation history of the Universe up
to z~1.5, using optical galaxies as tracers of the global radio emission.


title:
Multiply generated dynamical systems and the duality of higher rank
  graph algebras

abstract:
  We define a semidirect product groupoid of a system of partially defined
local homeomorphisms $T=(T_{1},..., T_{r})$. We prove that this construction
gives rise to amenable groupoids. The associated algebra is a Cuntz-like
algebra. We use this construction for higher rank graph algebras in order to
give a topological interpretation for the duality in $E$-theory between
$C^{*}(\Lambda)$ and $C^{*}(\Lambda^{op})$.


title: Cohomology $C_{\infty}$-algebra and Rational Homotopy Type

abstract:
  In the rational cohomology of a 1-connected space a structure of
$C_{\infty}$-algebra is constructed and it is shown that this object determines
the rational homotopy type


title:
Unconventional superconductivity originating from disconnected Fermi
  surfaces in the iron-based compound

abstract:
  The iron-based LaFeAsO$_{1-x}$F$_x$ recently discovered by Hosono's group is
a fresh theoretical challenge as a new class of high-temperature
superconductors. Here we describe the electronic structure of the material and
the mechanism of superconductivity. We start with constructing a tight-binding
model in terms of the maximally localized Wannier orbitals from a
first-principles electronic structure calculation, which has turned out to
involve all the five Fe 3d bands. This is used to calculate the spin and charge
susceptibilities with the random phase approximation. The spin susceptibility
has peaks around ${\Vec k} = (\pi, 0), (0, \pi)$ arising from a nesting across
disconnected Fermi surface pockets. We have then plugged the susceptibilities
into the linearised Eliashberg equation. For the doping concentration $x =
0.1$, we obtain an unconventional s-wave pairing, which is roughly an extended
s in that the gap changes sign between the Fermi pockets, but the gap function
is actually a 5$\times$5 matrix. Its experimental implications are also
discussed.


title: Critical Review of Basic Afterglow Concepts

abstract:
  The long lived afterglow emission that follows gamma-ray bursts (GRBs) was
predicted prior to its detection in 1997, in the X-rays, optical and radio. It
is thought to arise from the shock that is driven into the external medium as
the latter decelerates the relativistic outflow that drives the GRB, and
persists well after most of the energy in the outflow is transferred to the
shocked external medium. As the blast wave decelerates, the typical emission
frequency shifts to longer wavelength. Recent observations following the launch
of the Swift satellite challenge the traditional afterglow modeling and call
into questions some of the basic underlying concepts. This brief review
outlines some of the major strengths and weaknesses of the standard afterglow
model, as well as some of the challenges that it faces in explaining recent
data, and potential directions for future study that may eventually help
overcome some of the current difficulties.


title:
Geometric construction of the r-map: from affine special real to special
  K\"ahler manifolds

abstract:
  We give an intrinsic definition of (affine very) special real manifolds and
realise any such manifold $M$ as a domain in affine space equipped with a
metric which is the Hessian of a cubic polynomial. We prove that the tangent
bundle $N=TM$ carries a canonical structure of (affine) special K\"ahler
manifold. This gives an intrinsic description of the $r$-map as the map
$M\mapsto N=TM$. On the physics side, this map corresponds to the dimensional
reduction of rigid vector multiplets from 5 to 4 space-time dimensions. We
generalise this construction to the case when $M$ is any Hessian manifold.


title:
Discovery of photospheric CaX emission lines in the far-UV spectrum of
  the hottest known white dwarf (KPD0005+5106)

abstract:
  For the first time, we have identified photospheric emission lines in the
far-UV spectrum of a white dwarf. They were discovered in the Far Ultraviolet
Spectroscopic Explorer spectrum of the hot (Teff~200,000 K) DO white dwarf
KPD0005+5106 and they stem from extremely highly ionized calcium (CaX 1137,
1159 Ang). Their photospheric origin is confirmed by non-LTE line-formation
calculations. This is the highest ionisation stage of any element ever observed
in a stellar photosphere. Calcium has never been detected before in any hot
white dwarf or central star of planetary nebula. The calcium abundance
determination for KPD0005+5106 (1-10 times solar) is difficult, because the
line strengths are rather sensitive to current uncertainties in the knowledge
of effective temperature and surface gravity. We discuss the possibility that
the calcium abundance is much lower than expected from diffusion/levitation
equilibrium theory. The same emission lines are exhibited by the [WCE]-type
central star NGC2371. Another CaX line pair (1461, 1504 Ang) is probably
present in a Hubble Space Telescope spectrum of the PG1159-type central star
NGC246.


title: Entropy entrainment and dissipation in superfluid Helium

abstract:
  Building on a general variational framework for multi-fluid dynamics, we
discuss finite temperature effects in superfluids. The main aim is to provide
insight into the modelling of more complex finite temperature superfluid
systems, like the mixed neutron superfluid/proton superconductor that is
expected in the outer core of a neutron star. Our final results can also (to a
certain extent) be used to describe colour-flavour locked quark superconductors
that may be present at the extreme densities in the deep neutron star core. As
a demonstration of the validity of the model, which is based on treating the
excitations in the system as a massless ``entropy'' fluid, we show that it is
formally equivalent to the traditional two-fluid approach for superfluid
Helium. In particular, we highlight the fact that the entropy entrainment
encodes the ``normal fluid density'' of the traditional approach. We also show
how the superfluid constraint of irrotationality reduces the number of
dissipation coefficients in the system. This analysis provides insight into the
more general problem when vortices are present in the superfluid, and we
discuss how the so-called mutual friction force can be accounted for in our
framework. The end product is a hydrodynamic formalism for finite temperature
effects in a single superfluid condensate. This framework can readily be
extended to more complex situations.


title: Recent algorithm and machine developments for lattice QCD

abstract:
  I review recent machine trends and algorithmic developments for dynamical
lattice QCD simulations with the HMC algorithm for Wilson-type fermions. The
topics include the trend toward multi-core processors and general purpose GPU
(GPGPU) computing, and improvements on the quark determinant preconditioning,
molecular dynamics integrator, and quark solvers. I also discuss the prospect
on the use of these techniques on the forthcoming petaflops machines.


title: A Flaring X-ray Source with an Halpha-bright Counterpart toward the SMC

abstract:
  We report the discovery of a flaring X-ray source with an optical counterpart
with Halpha emission and red-excess, in the direction of the SMC. A 100 ksec
X-ray observation with Chandra detected a flare lasting 6 ksec in the source
CXO J005428.9-723107. The X-ray spectrum during the flare was consistent with a
thermal plasma of temperature kT=2.5 keV. In quiescence following the flare the
spectrum was softer (kT= 0.4 keV). Timing analysis did not reveal any
significant periodicities or QPOs. Optical images taken with the Magellan-Baade
6.5m telescope show a single star in the (0.9") error circle. This star has
apparent magnitude V=19.17, exhibits enhanced Halpha emission (Halpha - r =
-0.88), and has a large proper motion. Alternative explanations are explored,
leading to identification as a relatively nearby (Galactic) coronally active
star of the BY Draconis class.


title: Open statistical issues in particle physics

abstract:
  Many statistical issues arise in the analysis of Particle Physics
experiments. We give a brief introduction to Particle Physics, before
describing the techniques used by Particle Physicists for dealing with
statistical problems, and also some of the open statistical questions.


title: Best-Effort Strategies for Losing States

abstract:
  We consider games played on finite graphs, whose goal is to obtain a trace
belonging to a given set of winning traces. We focus on those states from which
Player 1 cannot force a win. We explore and compare several criteria for
establishing what is the preferable behavior of Player 1 from those states.
  Along the way, we prove several results of theoretical and practical
interest, such as a characterization of admissible strategies, which also
provides a simple algorithm for computing such strategies for various common
goals, and the equivalence between the existence of positional winning
strategies and the existence of positional subgame perfect strategies.


title: Shear Viscosity from Effective Couplings of Gravitons

abstract:
  We calculate the shear viscosity of field theories with gravity duals using
Kubo-formula by calculating the Green function of dual transverse gravitons and
confirm that the value of the shear viscosity is fully determined by the
effective coupling of transverse gravitons on the horizon. We calculate the
effective coupling of transverse gravitons for Einstein and Gauss-Bonnet
gravities coupled with matter fields, respectively. Then we apply the resulting
formula to the case of AdS Gauss-Bonnet gravity with $F^4$ term corrections of
Maxwell field and discuss the effect of $F^4$ terms on the ratio of the shear
viscosity to entropy density.


title: Revealing the fastest component of the DG Tau outflow through X-rays

abstract:
  Some T Tauri stars show a peculiar X-ray spectrum that can be modelled by two
components with different absorbing column densities. We seek to explain the
soft X-ray component in DG Tau, the best studied of these sources, with an
outflow model, taking observations at other wavelengths into consideration. We
constrain the outflow properties through spectral fitting and employ simple
semi-analytical formulae to describe properties of a shock wave that heats up
the X-ray emitting region. The X-ray emission is consistent with its arising
from the fastest and innermost component of the optically detected outflow.
Only a small fraction of the total mass loss is required for this X-ray
emitting component. Our favoured model requires shock velocities between 400
and 500 km/s. For a density >10^5 /cm^3 all dimensions of the shock cooling
zone are only a few AU, so even in optical observations this cannot be
resolved. This X-ray emission mechanism in outflows may also operate in other,
less absorbed T Tauri stars, in addition to corona and accretion spots.


title: Pseudodifferential operators on manifolds with linearization

abstract:
  We present in this paper the construction of a pseudodifferential calculus on
smooth non-compact manifolds associated to a globally defined and coordinate
independant complete symbol calculus, that generalizes the standard
pseudodifferential calculus on $\R^n$. We consider the case of manifolds $M$
with linearization in the sense of Bokobza-Haggiag, such that the associated
(abstract) exponential map provides global diffeomorphisms of $M$ with $\R^n$
at any point. Cartan--Hadamard manifolds are special cases of such manifolds.
The abstract exponential map encodes a notion of infinity on the manifold that
allows, modulo some hypothesis of $S_\sigma$-bounded geometry, to define the
Schwartz space of rapidly decaying functions, globally defined Fourier
transformation and classes of symbols with uniform and decaying control over
the $x$ variable. Given a linearization on the manifold with some properties of
control at infinity, we construct symbol maps and $\la$-quantization, explicit
Moyal star-product on the cotangent bundle, and classes of pseudodifferential
operators. We show that these classes are stable under composition, and that
the $\la$-quantization map gives an algebra isomorphism (which depends on the
linearization) between symbols and pseudodifferential operators. We study, in
our setting, $L^2$-continuity and give some examples. We show in particular
that the hyperbolic 2-space $\HH$ has a $S_1$-bounded geometry, allowing the
construction of a global symbol calculus of pseudodifferential operators on
$\S(\HH)$.


title:
Explicit illustration of non-abelian fusion rules in a small spin
  lattice

abstract:
  We exactly solve a four-site spin model with site-dependent Kitaev's coupling
in a tetrahedron by means of an analytical diagonalization. The non-abelian
fusion rules of eigen vortex excitations in this small lattice model are
explicitly illustrated in real space by using Pauli matrices. Comparing with
solutions of Kitaev models on large lattices, our solution gives an intuitional
picture using real space spin configurations to directly express zero modes of
Majorana fermions, non-abelian vortices and non-abelian fusion rules. We
generalize the single tetrahedron model to a chain model of tetrahedrons on a
torus and find the non-abelian vortices become well-defined non-abelian anyons.
We believe these manifest results are very helpful to demonstrate the
nonabelian anyon in laboratory.


title: A highly collimated jet from the low mass proto-star NGC1333 IRAS 4B

abstract:
  We imaged the protostars of the nearby region NGC1333 IRAS 4 in the water
maser line at 22.2 GHz by using the VLBA in phase referencing at milliarcsecond
scale over four epochs spaced by one month to measure proper motions. We
measure the absolute positions and proper motions of the H2O spots to
investigate the kinematics of the region from where the jet is launched.
  Two protostars (A2 and B) have been detected in a highly variable H2O maser
emission, with an active phase shorter than four weeks. A 70 AU chain of
several maser spots, very well aligned, has been observed close to the B
protostar. The apparent proper motions have been derived, finding that the H2O
spots are moving along the N-NW direction with projected velocities between 10
and 50 km/s. We conclude that in IRAS 4B, water maser trace a highly collimated
bipolar jet clearly associated with the protostar.


title:
Diphoton signals in theories with large extra dimensions to NLO QCD at
  hadron colliders

abstract:
  We present a full next-to-leading order (NLO) QCD corrections to diphoton
production at the hadron colliders in both standard model and ADD model. The
invariant mass and rapidity distributions of the diphotons are obtained using a
semi-analytical two cut-off phase space slicing method which allows for a
successful numerical implementation of various kinematical cuts used in the
experiments. The fragmentation photons are systematically removed using
smooth-cone-isolation cuts on the photons. The NLO QCD corrections not only
stabilise the perturbative predictions but also enhance the production cross
section significantly.


title: First Results from the IceTop Air Shower Array

abstract:
  IceTop is a 1 km^2 air shower detector presently under construction as a part
of the IceCube Observatory at South Pole. It will consist of 80 detector
stations, each equipped with two ice Cherenkov tanks, which cover 1 km^2. In
2008, the detector is half completed. One of the design goals of the detector
is to investigate cosmic rays in the energy range from the knee up to
approaching 1 EeV and study the mass composition of primary cosmic rays.
  In this report the performance of IceTop, the shower reconstruction
algorithms and first results, obtained with one month of data with an array of
26 stations operated in 2007, will be presented. Preliminary results are shown
for the cosmic ray energy spectrum in the range of 1 to 80 PeV. Being located
at an atmospheric depth of only 700 g/cm^2 at the South Pole, a high
sensitivity of the zenith angle distribution to the mass composition is
observed.
  The main advantage of IceTop, compared to other detectors in this energy
range, is the possibility to measure highly energetic muons from air showers in
coincidence with the IceCube detector. The muon rate at a given air shower
energy is sensitive to mass composition. The prospects of this method and
alternative methods to scrutinise different composition models will be
presented.


title:
Free-fall expansion of finite-temperature Bose-Einstein condensed gas in
  the non Thomas-Fermi regime

abstract:
  We report on our study of the free-fall expansion of a finite-temperature
Bose-Einstein condensed cloud of 87Rb. The experiments are performed with a
variable total number of atoms while keeping constant the number of atoms in
the condensate. The results provide evidence that the BEC dynamics depends on
the interaction with thermal fraction. In particular, they provide experimental
evidence that thermal cloud compresses the condensate.


title:
Rationale for $10^{14}$ enhancement factor in single molecule Raman
  spectroscopy

abstract:
  We extend the Purcell's original idea [Phys. Rev. \textbf{69}, 682 (1946)] on
modification of photon spontaneous \textit{emission} rate to modification of
photon spontaneous \textit{scattering} rate. We find the interplay of local
incident field enhancement and local density of photon states enhancement in
close proximity to a silver nanoparticle may result in up to $10^{14}$-fold
rise of Raman scattering cross-section. Thus single molecule Raman detection is
found to be explained by consistent quantum electrodynamic description without
any chemical mechanism involved. A model of the so-called "hot points" in
surface enhanced spectroscopy has been elaborated as local areas with high
Q-factor at incident and scattered (emitted) light frequencies. For
verification of the model we consider further experiments including transient
Raman experiments to clarify incident field enhancement and scanning near-field
optical mapping of local density of photon states.


title:
An upper bound on the exceptional characteristics for Lusztig's
  character formula

abstract:
  We develop and study a Lefschetz theory in a combinatorial category
associated to a root system and derive an upper bound on the exceptional
characteristics for Lusztig's formula for the simple rational characters of a
reductive algebraic group. Our bound is huge compared to the Coxeter number. It
is, however, given by an explicit formula.


title: Tests of AMiBA Data Integrity

abstract:
  We describe methods used to validate data from the Y.T. Lee Array for
Microwave Background Anisotropy (AMiBA), an interferometric array designed to
measure the Sunyaev-Zel'dovich effect and the anisotropy of the Cosmic
Microwave Background (CMB). We perform several statistical tests on data from
pointed galaxy cluster observations taken in 2007 and noise data from long-term
blank sky observations and measurements with the feeds covered by the
absorbers. We apply power spectrum analysis, cross power spectrum analysis
among different outputs with different time lags in our analog correlator, and
sample variance law tests to noise data. We find that (1) there is no time
variation of electronic offsets on the time scale of our two-patch observations
(~10 minutes); (2) noise is correlated by less than 10% between different lags;
and (3) the variance of noise scales with the inverse of time. To test the
Gaussianity of the data, we apply Kolmogorov-Smirnov (K-S) tests to cluster
data, and find that a 5% significance level efficiently detects data sets with
known hardware problems without rejecting an excess of acceptable data. We also
calculate third- and fourth-order moments and cumulants for the noise residual
visibilities and find that about 95% of our data are within the 99% confidence
regions of Gaussianity.


title: Solving the Observer Metric

abstract:
  The analysis of modern cosmological data is becoming an increasingly
important task as the amount of data multiplies. An important goal is to
extract geometric information, i.e. the metric of the cosmos, from
observational data. The observer metric is adapted to the reality of
observations: information received along the past null cone, and matter flowing
along timelike lines. It provides a potentially very good candidate for a
developing general numerical data reduction program. As a basis for this, we
elucidate the spherically symmetric solution, for which there is to date single
presentation that is complete and correct. With future numerical implementation
in mind, we give a clear presentation of the mathematical solution in terms of
4 arbitrary functions, the solution algorithm given observational data on the
past null cone, and we argue that the evolution from one null cone to the next
necessarily involves integrating down each null cone.


title: Simulating weak lensing on CMB maps

abstract:
  We present a fast, arbitrarily accurate method to simulate the effect of
gravitational lensing of the Cosmic Microwave Background anisotropies and
polarization fields by large scale structures. We demonstrate the efficiency
and accuracy of the method and exhibit their dependence on the algorithm
parameters.


title:
On hyperbolic once-punctured-torus bundles III: Comparing two
  tessellations of the complex plane

abstract:
  To each once-punctured-torus bundle, $T_\phi$, over the circle with
pseudo-Anosov monodromy $\phi$, there are associated two tessellations of the
complex plane: one, $\Delta(\phi)$, is (the projection from $\infty$ of) the
triangulation of a horosphere at $\infty$ induced by the canonical
decomposition into ideal tetrahedra, and the other, $CW(\phi)$, is a fractal
tessellation given by the Cannon-Thurston map of the fiber group switching back
and forth between gray and white each time it passes through $\infty$. In this
paper, we study the relation between $\Delta(\phi)$ and $CW(\phi)$.


title: Predictive learning via rule ensembles

abstract:
  General regression and classification models are constructed as linear
combinations of simple rules derived from the data. Each rule consists of a
conjunction of a small number of simple statements concerning the values of
individual input variables. These rule ensembles are shown to produce
predictive accuracy comparable to the best methods. However, their principal
advantage lies in interpretation. Because of its simple form, each rule is easy
to understand, as is its influence on individual predictions, selected subsets
of predictions, or globally over the entire space of joint input variable
values. Similarly, the degree of relevance of the respective input variables
can be assessed globally, locally in different regions of the input space, or
at individual prediction points. Techniques are presented for automatically
identifying those variables that are involved in interactions with other
variables, the strength and degree of those interactions, as well as the
identities of the other variables with which they interact. Graphical
representations are used to visualize both main and interaction effects.


title:
MAGIC upper limits to the VHE gamma-ray flux of 3C454.3 in high emission
  state

abstract:
  We report upper limits to the very high energy flux (E>100 GeV) of the flat
spectrum radio quasar 3C454.3 (z=0.859) derived by the Cherenkov telescope
MAGIC during the high states of July/August and November/December 2007. We
compare the upper limits derived in both time slots with the available
quasi-simultaneous MeV-GeV data from the AGILE gamma-ray satellite and
interpret the observational results in the context of leptonic emission models.
The source was observed with the MAGIC telescope during the active phases of
July-August 2007 and November-December 2007 and the data were analyzed with the
MAGIC standard analysis tools. For the periods around the ends of July and
November, characterized by the most complete multifrequency coverage, we
constructed the spectral energy distributions using our data together with
nearly simultaneous multifrequency (optical, UV, X-ray and GeV) data. Only
upper limits can be derived from the MAGIC data. The upper limits, once
corrected for the expected absorption by the extragalactic background light,
together with nearly simultaneous multifrequency data, allow us to constrain
the spectral energy distribution of 3C454.3. The data are consistent with the
model expectations based on the inverse Compton scattering of the ambient
photons from the broad line region by relativistic electrons, which robustly
predicts a sharp cut-off above 20-30 GeV.


title: First measurement of direct $f_0(980)$ photoproduction on the proton

abstract:
  We report on the results of the first measurement of exclusive $f_0(980)$
meson photoproduction on protons for $E_\gamma=3.0 - 3.8$ GeV and $-t =
0.4-1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas
Jefferson National Accelerator Facility. The resonance was detected via its
decay in the $\pi^+ \pi^-$ channel by performing a partial wave analysis of the
reaction $\gamma p \to p \pi^+ \pi^-$. Clear evidence of the $f_0(980)$ meson
was found in the interference between $P$ and $S$ waves at $M_{\pi^+ \pi^-}\sim
1$ GeV. The $S$-wave differential cross section integrated in the mass range of
the $f_0(980)$ was found to be a factor of 50 smaller than the cross section
for the $\rho$ meson. This is the first time the $f_0(980)$ meson has been
measured in a photoproduction experiment.


title:
The nearby eclipsing stellar system delta Velorum - I. Origin of the
  infrared excess from VISIR and NACO imaging

abstract:
  - Context: The triple stellar system delta Vel system presents a significant
infrared excess, whose origin is still being debated. A large infrared bow
shock has been discovered using Spitzer/MIPS observations. Although it appears
as a significant contributor to the measured IR excess, the possibility exists
that a circumstellar IR excess is present around the stars of the system. -
Aims: The objective of the present VISIR and NACO observations is to identify
whether one of the stars of the delta Vel system presents a circumstellar
photometric excess in the thermal IR domain and to quantify it. - Methods: We
observed delta Vel using the imaging modes of the ESO/VLT instruments VISIR (in
BURST mode) and NACO to resolve the A-B system (0.6" separation) and obtain the
photometry of each star. We also obtained one NACO photometry epoch precisely
at the primary (annular) eclipse of delta Vel Aa by Ab. - Results: Our
photometric measurements with NACO (2.17 mic), complemented by the existing
visible photometry allowed us to reconstruct the spectral energy distribution
of the three stars. We then compared the VISIR photometry (8.6-12.8 mic) to the
expected photospheric emission from the three stars at the corresponding
wavelengths. - Conclusions: We can exclude the presence of a circumstellar
thermal infrared excess around delta Vel A or B down to a few percent level.
This supports the conclusions of Gaspar et al. (2008) that the IR excess of
delta Vel has an interstellar origin, although a cold circumstellar disk could
still be present. In addition, we derive the spectral types of the three stars
Aa, Ab, and B (respectively A2IV, A4V and F8V), and we estimate the age of the
system around 400-500 Myr.


title:
Excess Specific Heat of Ptfe and Pctfe at Low Temperatures:
  Approximation Details

abstract:
  Approximation of the previously estimated excess specific heat
C^{excess}/T^{5} of two fluoropolymers, PTFE and PCTFE, is presented using
Orthonormal Polynomial Expansion Method (OPEM). The new type of weighting
functions in OPEM involves the experimental errors in every point of the
studied thermal characteristic. The investigated temperature dependence of the
function C^{excess}/T^{5} is described in the whole temperature ranges 0.4\div8
K and 2.5\div7 K respectively for PTFE and PCTFE as well as in two subintervals
(0.4\div2) K, (2.5\div8) K for PTFE. Numerical results of the deviations
between the given C^{excess}/T^{5} data and their approximating values are
given. The usual polynomial coefficients obtained by orthonormal ones in our
OPEM approach and the calculated in every point absolute, relative and specific
sensitivities of the studied thermal characteristic are proposed too. The
approximation parameters of this type thermal characteristic are shown in
Figures and Tables.


title: A generalized quantum SWAP gate

abstract:
  The SWAP gate plays a central role in network designs for qubit quantum
computation. However, there is a view to generalize qubit quantum computing to
higher dimensional quantum systems. In this paper we construct a generalized
SWAP gate using only instances of the generalized controlled-NOT gate to
cyclically permute the states of $d$ qudits for $d$ prime.


title:
Electronic and transport properties of rectangular graphene
  macromolecules and zigzag carbon nanotubes of finite length

abstract:
  We study one dimensional (1D) carbon ribbons with the armchair edges and the
zigzag carbon nanotubes and their counterparts with finite length (0D) in the
framework of the H\"{u}ckel model. We prove that a 1D carbon ribbon is metallic
if its width (the number of carbon rings) is equal to $2+3n$. We show that the
dispersion law (electron band energy) of a 1D metallic ribbon or a 1D metallic
carbon nanotube has a universal {\it sin-}like dependence at the Fermi energy
which is independent of its width. We find that in case of metallic graphene
ribbons of finite length (rectangular graphene macromolecules) or nanotubes of
finite length the discrete energy spectrum in the vicinity of $\varepsilon=0$
(Fermi energy) can be obtained exactly by selecting levels from the same
dispersion law. In case of a semiconducting graphene macromolecule or a
semiconducting nanotube of finite length the positions of energy levels around
the energy gap can be approximated with a good accuracy. The electron spectrum
of 0D carbon structures often include additional states at energy
$\varepsilon=0$, which are localized on zigzag edges and do not contribute to
the volume conductivity.


title:
Sequential category aggregation and partitioning approaches for
  multi-way contingency tables based on survey and census data

abstract:
  Large contingency tables arise in many contexts but especially in the
collection of survey and census data by government statistical agencies.
Because the vast majority of the variables in this context have a large number
of categories, agencies and users need a systematic way of constructing tables
which are summaries of such contingency tables. We propose such an approach in
this paper by finding members of a class of restricted log-linear models which
maximize the likelihood of the data and use this to find a parsimonious means
of representing the table. In contrast with more standard approaches for model
search in hierarchical log-linear models (HLLM), our procedure systematically
reduces the number of categories of the variables. Through a series of
examples, we illustrate the extent to which it can preserve the interaction
structure found with HLLMs and be used as a data simplification procedure prior
to HLL modeling. A feature of the procedure is that it can easily be applied to
many tables with millions of cells, providing a new way of summarizing large
data sets in many disciplines. The focus is on information and description
rather than statistical testing. The procedure may treat each variable in the
table in different ways, preserving full detail, treating it as fully nominal,
or preserving ordinality.


title: Even-odd effects in finite Heisenberg spin chains

abstract:
  Magnetic superlattices and nanowires may be described as Heisenberg spin
chains of finite length N, where N is the number of magnetic units (films or
atoms, respectively). We study antiferromagnetically coupled spins which are
also coupled to an external field H (superlattices) or to a ferromagnetic
substrate (nanowires). The model is analyzed through a two-dimensional map
which allows fast and reliable numerical calculations. Both open and closed
chains have different properties for even and odd N (parity effect). Open
chains with odd N are known [S.Lounis et al., Phys. Rev. Lett. 101, 107204
(2008)] to have a ferrimagnetic state for small N and a noncollinear state for
large N. In the present paper, the transition length N_c is found analytically.
Finally, we show that closed chains arrange themselves in the uniform bulk
spin-flop state for even N and in nonuniform states for odd N.


title:
Effect of Central Mass Concentration on the Formation of Nuclear Spirals
  in Barred Galaxies

abstract:
  We have performed smoothed particle hydrodynamics (SPH) simulations to study
the response of the central kiloparsec region of a gaseous disk to the
imposition of nonaxisymmetric bar potentials. The model galaxies are composed
of the three axisymmetric components (halo, disk, and bulge) and a
non-axisymmetric bar. These components are assumed to be invariant in time in
the frame corotating with the bar. The potential of spherical $\gamma$-models
of Dehnen is adopted for the bulge component whose density varies as
$r^{-\gamma}$ near the center and $r^{-4}$ at larger radiiand hence, possesses
a central density core for $\gamma = 0$ and cusps for $\gamma > 0$. Since the
central mass concentration of the model galaxies increases with the cusp
parameter $\gamma$, we have examined here the effect of the central mass
concentration by varying the cusp parameter $\gamma$ on the mechanism
responsible for the formation of the symmetric two-armed nuclear spirals in
barred galaxies. Our simulations show that the symmetric two-armed nuclear
spirals are formed by hydrodynamic spiral shocks driven by the gravitational
torque of the bar for the models with $\gamma = 0$ and 0.5. On the other hand,
the symmetric two-armed nuclear spirals in the models with $\gamma=1$ and 1.5
are explained by gas density waves. Thus, we conclude that the mechanism
responsible for the formation of the symmetric two-armed nuclear spirals in
barred galaxies changes from the hydrodynamic shocks to the gas density waves
when the central mass concentration increases from $\gamma = 0$ to 1.5.


title:
Energy dissipation and self-similar solutions for an unforced inviscid
  dyadic model

abstract:
  A shell-type model of an inviscid fluid, previously considered in the
literature, is investigated in absence of external force. Energy dissipation of
positive solutions is proved and decay of energy like $t^{-2}$ is established.
Self-similar decaying positive solutions are introduced and proved to exist and
classified. Coalescence and blow-up are obtained as a consequence, in the class
of arbitrary sign solutions.


title: SU(N) membrane $B\wedge F$ theory with dual-pairs

abstract:
  We construct a SU(N) membrane $B\wedge F$ theory with dual pairs of scalar
and tensor fields. The moduli space of the theory is precisely that of $N$
M2-branes on the noncompact flat space. The theory possesses explicit SO(8)
invariance and is an extension of the maximal SU(N) super-Yang-Mills theory.


title: Towards a gauge-polyvalent Numerical Relativity code

abstract:
  The gauge polyvalence of a new numerical code is tested, both in
harmonic-coordinate simulations (gauge-waves testbed) and in
singularity-avoiding coordinates (simple Black-Hole simulations, either with or
without shift). The code is built upon an adjusted first-order
flux-conservative version of the Z4 formalism and a recently proposed family of
robust finite-difference high-resolution algorithms. An outstanding result is
the long-term evolution (up to 1000M) of a Black-Hole in normal coordinates
(zero shift) without excision.


title: Neutrino absorption by W production in the presence of a magnetic field

abstract:
  In this work we calculate the decay rate of the electron type neutrinos into
$W$ bosons and electrons in presence of an external uniform magnetic field. The
decay rate is calculated from the imaginary part of the $W$ exchange neutrino
self-energy diagram but in the weak field limit and compare our result with the
existing one.


title: Protection Schemes for Two Link Failures in Optical Networks

abstract:
  In this paper we develop network protection schemes against two link failures
in optical networks. The motivation behind this work is the fact that the
majority of all available links in an optical network suffer from single and
double link failures. In the proposed network protection schemes, NPS2-I and
NPS2-II, we deploy network coding and reduced capacity on the working paths to
provide backup protection paths. In addition, we demonstrate the encoding and
decoding aspects of the proposed schemes.


title: Pair weakening in mixed rare-earth nickel borocarbides (R,R')Ni2B2C

abstract:
  In this study pseudoquaternary rare-earth nickel borocarbide superconductors
RxR'1-xNi2B2C have been investigated predominantly in the diluted limit x << 1
or (1 x) << 1. In all of these materials structural disorder results in a
reduction of the superconducting transition temperature Tc . Depending on the
selection of the rare earth elements R and R' this disorder induced
deterioration of superconductivity is combined with magnetic pair breaking of
Abrikosov-Gorkov type or pair breaking of non-magnetic impurities in
antiferromagnetic superconductors (Morozov-type of pair breaking).


title:
The role of the Pauli principle in three-cluster systems composed of
  identical clusters

abstract:
  Within the microscopic model based on the algebraic version of the resonating
group method the role of the Pauli principle in the formation of continuum wave
function of nuclear systems composed of three identical $s$-clusters has been
investigated. Emphasis is placed upon the study of the exchange effects
contained in the genuine three-cluster norm kernel. Three-fermion, three-boson,
three-dineutron ($3d'$) and $3\alpha$ systems are considered in detail. Simple
analytical method of constructing the norm kernel for $3\alpha$ system is
suggested. The Pauli-allowed basis functions for the $3\alpha$ and $3d'$
systems are given in an explicit form and asymptotic behavior of these
functions is established. Complete classification of the eigenfunctions and the
eigenvalues of the $^{12}$C norm kernel by the $^8$Be$=\alpha+\alpha$
eigenvalues has been given for the first time. Spectrum of the $^{12}$C norm
kernel is compared to that of the $^{5}$H system.


title: Measure changes with extinction

abstract:
  We consider a change of measure by a martingale $Z_t$ and clarify that in
general $1/Z_t$ is only a supermartingale under the changed measure. We then
give a necessary and sufficient condition for the event that the limit of the
martingale is zero to coincide with the event that the martingale hits zero in
finite time (up to a set of zero probability).


title: A Sharper discrepancy measure for post-election audits

abstract:
  Post-election audits use the discrepancy between machine counts and a hand
tally of votes in a random sample of precincts to infer whether error affected
the electoral outcome. The maximum relative overstatement of pairwise margins
(MRO) quantifies that discrepancy. The electoral outcome a full hand tally
shows must agree with the apparent outcome if the MRO is less than 1. This
condition is sharper than previous ones when there are more than two candidates
or when voters may vote for more than one candidate. For the 2006 U.S. Senate
race in Minnesota, a test using MRO gives a $P$-value of 4.05% for the
hypothesis that a full hand tally would find a different winner, less than half
the value Stark [Ann. Appl. Statist. 2 (2008) 550--581] finds.


title: Fixed points in interacting dark energy models

abstract:
  The dynamical behaviors of two interacting dark energy models are considered.
In addition to the scaling attractors found in the non-interacting quintessence
model with exponential potential, new accelerated scaling attractors are also
found in the interacting dark energy models. The coincidence problem is reduced
to the choice of parameters in the interacting dark energy models.


title:
Toward constraints on galaxy formation scenarios: stellar properties
  from Galactic surveys

abstract:
  We present some of the strategies being developed to classify and
parameterize objects obtained with spectra from the Sloan Digital Sky Survey
(SDSS) and the RAdial Velocity Experiment (RAVE) and present some results. We
estimate stellar atmospheric parameters (effective temperature, gravity, and
metallicity) from spectral and photometric data and use these to analyse
Galactic populations. We demonstrate this through the selection of a sample of
candidate Blue Horizontal-Branch and RR Lyrae stars selected from SDSS/SEGUE.


title: Testing significance of features by lassoed principal components

abstract:
  We consider the problem of testing the significance of features in
high-dimensional settings. In particular, we test for differentially-expressed
genes in a microarray experiment. We wish to identify genes that are associated
with some type of outcome, such as survival time or cancer type. We propose a
new procedure, called Lassoed Principal Components (LPC), that builds upon
existing methods and can provide a sizable improvement. For instance, in the
case of two-class data, a standard (albeit simple) approach might be to compute
a two-sample $t$-statistic for each gene. The LPC method involves projecting
these conventional gene scores onto the eigenvectors of the gene expression
data covariance matrix and then applying an $L_1$ penalty in order to de-noise
the resulting projections. We present a theoretical framework under which LPC
is the logical choice for identifying significant genes, and we show that LPC
can provide a marked reduction in false discovery rates over the conventional
methods on both real and simulated data. Moreover, this flexible procedure can
be applied to a variety of types of data and can be used to improve many
existing methods for the identification of significant features.


title:
Sufficient enlargements of minimal volume for finite dimensional normed
  linear spaces

abstract:
  Let $B_Y$ denote the unit ball of a normed linear space $Y$. A symmetric,
bounded, closed, convex set $A$ in a finite dimensional normed linear space $X$
is called a {\it sufficient enlargement} for $X$ if, for an arbitrary isometric
embedding of $X$ into a Banach space $Y$, there exists a linear projection
$P:Y\to X$ such that $P(B_Y)\subset A$. The main results of the paper: {\bf
(1)} Each minimal-volume sufficient enlargement is linearly equivalent to a
zonotope spanned by multiples of columns of a totally unimodular matrix. {\bf
(2)} If a finite dimensional normed linear space has a minimal-volume
sufficient enlargement which is not a parallelepiped, then it contains a
two-dimensional subspace whose unit ball is linearly equivalent to a regular
hexagon.


title: A Global Study of X-ray Binaries

abstract:
  We present preliminary results on a global study of X-ray binaries using 14
Ms of data from the Rossi X-ray Timing Explorer satellite. Our initial study on
GX 339-4 is recapped as an introduction to the methods used. We use a
consistent analysis scheme for all objects, with three different spectral
models to fit the powerlaw and disc components. We also take into account the
possibility of a line being present in the data. The resulting almost 4000
observations allow the tracking of the spectral properties of the binaries as
they evolve through an outburst. Our investigations concentrate on the disc and
line properties of the binaries when in outburst. We also show the
Disc-Fraction Luminosity diagram for the population of X-ray binaries studied
which will enable us to further links with AGN.


title: Skew-symmetric cluster algebras of finite mutation type

abstract:
  In 2003, Fomin and Zelevinsky obtained Cartan-Killing type classification of
all cluster algebras of finite type, i.e. cluster algebras having only finitely
many distinct cluster variables. A wider class of cluster algebras is formed by
cluster algebras of finite mutation type which have finitely many exchange
matrices (but are allowed to have infinitely many cluster variables). In this
paper we classify all cluster algebras of finite mutation type with
skew-symmetric exchange matrices. Besides cluster algebras of rank 2 and
cluster algebras associated with triangulations of surfaces there are exactly
11 exceptional skew-symmetric cluster algebras of finite mutation type. More
precisely, 9 of them are associated with root systems $E_6$, $E_7$, $E_8$,
$\widetilde E_6$, $\widetilde E_7$, $\widetilde E_8$, $E_6^{(1,1)}$,
$E_7^{(1,1)}$, $E_8^{(1,1)}$; two remaining were recently found by Derksen and
Owen. We also describe a criterion which determines if a skew-symmetric cluster
algebra is of finite mutation type, and discuss growth rate of cluster
algebras.


title: Branching Brownian motion: Almost sure growth along unscaled paths

abstract:
  We give new results on the growth of the number of particles in a dyadic
branching Brownian motion which follow within a fixed distance of a path
$f:[0,\infty)\to \mathbb{R}$. We show that it is possible to count the number
of particles without rescaling the paths. Our results reveal that the number of
particles along certain paths can oscillate dramatically. The methods used are
entirely probabilistic, taking advantage of the spine technique developed by,
amongst others, Lyons et al, Kyprianou, and Hardy & Harris.


title: Inference using shape-restricted regression splines

abstract:
  Regression splines are smooth, flexible, and parsimonious nonparametric
function estimators. They are known to be sensitive to knot number and
placement, but if assumptions such as monotonicity or convexity may be imposed
on the regression function, the shape-restricted regression splines are robust
to knot choices. Monotone regression splines were introduced by Ramsay
[Statist. Sci. 3 (1998) 425--461], but were limited to quadratic and lower
order. In this paper an algorithm for the cubic monotone case is proposed, and
the method is extended to convex constraints and variants such as
increasing-concave. The restricted versions have smaller squared error loss
than the unrestricted splines, although they have the same convergence rates.
The relatively small degrees of freedom of the model and the insensitivity of
the fits to the knot choices allow for practical inference methods; the
computational efficiency allows for back-fitting of additive models. Tests of
constant versus increasing and linear versus convex regression function, when
implemented with shape-restricted regression splines, have higher power than
the standard version using ordinary shape-restricted regression.


title: Weak measurements of non local variables

abstract:
  Methods for measuring the weak value of non local variables are investigated.
We analyze local (indirect) measurement methods for obtaining the weak values.
We also describe some new (direct) methods (Non local weak measurements) for
measuring the weak values of some non local variables.


title: Classical initial conditions in high energy nucleus-nucleus collisions

abstract:
  An iterative proceedure is proposed to compute the classical gauge field
produced in the collision of two heavy nuclei at high energy. The leading order
is obtained by linearizing the Yang-Mills equations in the light-cone gauge,
and provides a simple formula for gluon production in nucleus-nucleus
collisions. At this order $k_t-$factorization breaks down.


title: Nonlinear Prediction of Solar Cycle 24

abstract:
  Sunspot activity is highly variable and challenging to forecast. Yet
forecasts are important, since peak activity has profound effects on major
geophysical phenomena including space weather (satellite drag,
telecommunications outages) and has even been correlated speculatively with
changes in global weather patterns. This paper investigates trends in sunspot
activity, using new techniques for decadal-scale prediction of the present
solar cycle (cycle 24). First, Hurst exponent $H$ analysis is used to
investigate the autocorrelation structure of the putative dynamics; then the
Sugihara-May algorithm is used to predict the ascension time and the maximum
intensity of the current sunspot cycle. Here we report $H$ = 0.86 for the
complete sunspot number dataset (1700-2007) and $H$ = 0.88 for the reliable
sunspot data set (1848-2007). Using the Sugihara-May algorithm analysis, we
forecast that cycle 24 will reach its maximum in December 2012 at approximately
87 sunspots units.


title: Two Electrons in a Quantum Dot: A Unified Approach

abstract:
  Low-lying energy levels of two interacting electrons confined in a
two-dimensional parabolic quantum dot in the presence of an external magnetic
field have been revised within the frame of a novel model. The present
formalism, which gives closed algebraic solutions for the specific values of
magnetic field and spatial confinement length, enables us to see explicitly
individual effects of the electron correlation.


title: Slowdown estimates for ballistic random walk in random environment

abstract:
  For a random walk in an elliptic i.i.d. random environment in dimension
greater than or equal to 4, satisfying the a ballisticity condition slightly
weaker than condition (T'), We consider the probability of linear slowdown. We
show an upper bound for this probability which is very close to the lower bound
obtained by the "naive trap" analysis.
  As a tool for obtaining the main result, we show an almost local version of
the quenched central limit theorem under the same ballisticity condition.


title: Artificial Intelligence Techniques for Steam Generator Modelling

abstract:
  This paper investigates the use of different Artificial Intelligence methods
to predict the values of several continuous variables from a Steam Generator.
The objective was to determine how the different artificial intelligence
methods performed in making predictions on the given dataset. The artificial
intelligence methods evaluated were Neural Networks, Support Vector Machines,
and Adaptive Neuro-Fuzzy Inference Systems. The types of neural networks
investigated were Multi-Layer Perceptions, and Radial Basis Function. Bayesian
and committee techniques were applied to these neural networks. Each of the AI
methods considered was simulated in Matlab. The results of the simulations
showed that all the AI methods were capable of predicting the Steam Generator
data reasonably accurately. However, the Adaptive Neuro-Fuzzy Inference system
out performed the other methods in terms of accuracy and ease of
implementation, while still achieving a fast execution time as well as a
reasonable training time.


title: Basic Gravitational Currents and Killing-Yano Forms

abstract:
  It has been shown that for each Killing-Yano (KY)-form accepted by an
$n$-dimensional (pseudo)Riemannian manifold of arbitrary signature, two basic
gravitational currents can be defined. Conservation of the currents are
explicitly proved by showing co-exactness of the one and co-closedness of the
other. Some general geometrical facts implied by these conservation laws are
also elucidated. In particular, the conservation of the one-form currents
implies that the scalar curvature of the manifold is a flow invariant for all
of its Killing vector fields. It also directly follows that, while all KY-forms
and their Hodge duals on a constant curvature manifold are the eigenforms of
the Laplace-Beltrami operator, for an Einstein manifold this is certain only
for KY 1-forms, $(n-1)$-forms and their Hodge duals.


title: Pair and Impar, Even and Odd Form Fields and Electromagnetism

abstract:
  In this paper after reviewing the Schouten and de Rham definition of impair
and pair differential form fields (not to be confused with differential form
fields of even and odd grades) we prove that in a relativistic spacetime it is
possible (despite claims in contrary) to coherently formulate electromagnetism
(and we believe any other physical theory) using only pair form fields or, if
one wishes, using pair and impair form fields together, in an appropriate way.
Those two distinct descriptions involve only a mathematical choice and do not
seem to lead to any observable physical consequence if due care is taken.
Moreover, we show in details that a formulation of electromagnetic theory in
the Clifford bundle formalism of differential forms where the two Maxwell
equations of the so called free metric approach becomes a single equation is
compatible with both formulations of electromagnetism just mentioned above.
Moreover we derive directly from Maxwell equation the density of force
(coupling of the electromagnetic field with the charge current) that is a
postulate in the free metric approach to electromagnetism. We recall also a
formulation of the engineering version of Maxwell equations using electric and
magnetic fields as objects of the same nature, i.e., without using polar and
axial vectors.


title: Efficient Multiplication of Dense Matrices over GF(2)

abstract:
  We describe an efficient implementation of a hierarchy of algorithms for
multiplication of dense matrices over the field with two elements (GF(2)). In
particular we present our implementation -- in the M4RI library -- of
Strassen-Winograd matrix multiplication and the "Method of the Four Russians"
multiplication (M4RM) and compare it against other available implementations.
Good performance is demonstrated on on AMD's Opteron and particulary good
performance on Intel's Core 2 Duo. The open-source M4RI library is available
stand-alone as well as part of the Sage mathematics software.
  In machine terms, addition in GF(2) is logical-XOR, and multiplication is
logical-AND, thus a machine word of 64-bits allows one to operate on 64
elements of GF(2) in parallel: at most one CPU cycle for 64 parallel additions
or multiplications. As such, element-wise operations over GF(2) are relatively
cheap. In fact, in this paper, we conclude that the actual bottlenecks are
memory reads and writes and issues of data locality. We present our empirical
findings in relation to minimizing these and give an analysis thereof.


title:
Bergman polynomials on an Archipelago: Estimates, Zeros and Shape
  Reconstruction

abstract:
  Growth estimates of complex orthogonal polynomials with respect to the area
measure supported by a disjoint union of planar Jordan domains (called, in
short, an archipelago) are obtained by a combination of methods of potential
theory and rational approximation theory. The study of the asymptotic behavior
of the roots of these polynomials reveals a surprisingly rich geometry, which
reflects three characteristics: the relative position of an island in the
archipelago, the analytic continuation picture of the Schwarz function of every
individual boundary and the singular points of the exterior Green function. By
way of explicit example, fine asymptotics are obtained for the lemniscate
archipelago $|z^m-1|<r^m, 0<r<1,$ which consists of $m$ islands. The asymptotic
analysis of the Christoffel functions associated to the same orthogonal
polynomials leads to a very accurate reconstruction algorithm of the shape of
the archipelago, knowing only finitely many of its power moments. This work
naturally complements a 1969 study by H. Widom of Szeg\H{o} orthogonal
polynomials on an archipelago and the more recent asymptotic analysis of
Bergman orthogonal polynomials unveiled by the last two authors and their
collaborators.


title:
A Precise Measurement of the Neutron Magnetic Form Factor GMn in the
  Few-GeV2 Region

abstract:
  The neutron elastic magnetic form factor GMn has been extracted from
quasielastic electron scattering data on deuterium with the CEBAF Large
Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic coverage of the
measurement is continuous from Q2=1 GeV2 to 4.8 GeV2. High precision was
achieved by employing a ratio technique in which many uncertainties cancel, and
by a simultaneous in-situ calibration of the neutron detection efficiency, the
largest correction to the data. Neutrons were detected using the CLAS
electromagnetic calorimeters and the time-of-flight scintillators. Data were
taken at two different electron beam energies, allowing up to four
semi-independent measurements of GMn to be made at each value of Q2. The dipole
parameterization is found to provide a good description of the data over the
measured Q2 range.


title: Hyperellipticity and Klein bottle companionship in systolic geometry

abstract:
  Given a hyperelliptic Klein surface, we construct companion Klein bottles.
Bavard's short loops on companion bottles are studied in relation to the
surface to improve an inequality of Gromov's in systolic geometry.


title:
DMRG-study of current and activity fluctuations near non-equilibrium
  phase transitions

abstract:
  Cumulants of a fluctuating current can be obtained from a free energy-like
generating function which for Markov processes equals the largest eigenvalue of
a generalized generator. We determine this eigenvalue with the DMRG for
stochastic systems. We calculate the variance of the current in the different
phases, and at the phase transitions, of the totally asymmetric exclusion
process. Our results can be described in the terms of a scaling ansatz that
involves the dynamical exponent z. We also calculate the generating function of
the activity near the absorbing state transition of the contact process. Its
scaling properties can be expressed in terms of known critical exponents.


title: Phase space measure concentration for an ideal gas

abstract:
  We point out that a special case of an ideal gas exhibits concentration of
the volume of its phase space, which is a sphere, around its equator in the
thermodynamic limit. The rate of approach to the thermodynamic limit is
determined. Our argument relies on the spherical isoperimetric inequality of
L\'{e}vy and Gromov.

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


title:
Superconductor insulator transition in thin films driven by an orbital
  parallel magnetic field effect

abstract:
  We study theoretically orbital effects of a parallel magnetic field applied
to a disordered superconducting film. We find that the field reduces the phase
stiffness and leads to strong quantum phase fluctuations driving the system
into an insulating behavior. This microscopic model shows that the critical
field decreases with the sheet resistance, in agreement with recent
experimental results. The predictions of this model can be used to discriminate
spin and orbital effects. We find that experiments conducted by A. Johansson
\textit{et al.} are more consistent with the orbital mechanism.


title: Baryon Stopping as a new Probe of Geometric Scaling

abstract:
  We suggest to use net-baryon rapidity distributions in central relativistic
heavy-ion collisions at SPS, RHIC and LHC energies in order to probe saturation
physics. Within the color glass condensate framework based on small-coupling
QCD, net-baryon rapidity distributions are shown to exhibit geometric scaling.
In a comparison with RHIC data in Au + Au collisions at sqrt(s_NN) = 62.4 GeV
and 200 GeV the gradual approach to the gluon saturation regime is
investigated. Predictions for net-baryon rapidity spectra and the mean rapidity
loss in central Pb + Pb collisions at LHC energies of sqrt (s_NN) = 5.5 TeV are
made.


title:
Spectropolarimetery of umbral fine structures from Hinode: Evidence for
  magnetoconvection

abstract:
  We present spectropolarimetric analysis of umbral dots and a light bridge
fragment that show dark lanes in G-band images. Umbral dots show upflow as well
as associated positive Stokes V area asymmetry in their central parts. Larger
umbral dots show down flow patches in their surrounding parts that are
associated with negative Stokes V area asymmetry. Umbral dots show weaker
magnetic field in central part and higher magnetic field in peripheral area.
Umbral fine structures are much better visible in total circularly polarized
light than in continuum intensity. Umbral dots show a temperature deficit above
dark lanes. The magnetic field inclination show a cusp structure above umbral
dots and a light bridge fragment. We compare our observational findings with 3D
magnetohydrodynamic simulations.


title:
Finite-temperature Screening and the Specific Heat of Doped Graphene
  Sheets

abstract:
  At low energies, electrons in doped graphene sheets are described by a
massless Dirac fermion Hamiltonian. In this work we present a semi-analytical
expression for the dynamical density-density linear-response function of
noninteracting massless Dirac fermions (the so-called "Lindhard" function) at
finite temperature. This result is crucial to describe finite-temperature
screening of interacting massless Dirac fermions within the Random Phase
Approximation. In particular, we use it to make quantitative predictions for
the specific heat and the compressibility of doped graphene sheets. We find
that, at low temperatures, the specific heat has the usual normal-Fermi-liquid
linear-in-temperature behavior, with a slope that is solely controlled by the
renormalized quasiparticle velocity.