title:
The target asymmetry in hard vector-meson electroproduction and parton
  angular momenta

abstract:
  The target asymmetry for electroproduction of vector mesons is investigated
within the handbag approach. While the generalized parton distribution (GPD) H
is taken from a previous analysis of the elctroproduction cross section, we
here construct the GPD E from double distributions and constrain it by the
Pauli form factors of the nucleon, positivity bounds and sum rules. Predictions
for the target asymmetry are given for various vector mesons and discussed how
experimental data on the asymmetry will further constrain E and what we may
learn about the angular momenta the partons carry.


title:
Structure and Magnetism in Mn Doped Zirconia: Density-functional Theory
  Studies

abstract:
  Using the first-principles density-functional theory plan-wave
pseudopotential method, we investigate the structure and magnetism in 25% Mn
substitutive and interstitial doped monoclinic, tetragonal and cubic ZrO2
systematically. Our studies show that the introduction of Mn impurities into
ZrO2 not only stabilizes the high temperature phase, but also endows ZrO2 with
magnetism. Based on the simple crystal field theory (CFT), we discuss the
origination of magnetism in Mn doped ZrO2. Moreover, we discuss the effect of
electron donor on magnetic semiconductors, and the possibility as electronic
structure modulator.


title: Hilbert transforms and the Cauchy integral in euclidean space

abstract:
  We generalize the notion of harmonic conjugate functions and Hilbert
transforms to higher dimensional euclidean spaces, in the setting of
differential forms and the Hodge-Dirac system. These conjugate functions are in
general far from being unique, but under suitable boundary conditions we prove
existence and uniqueness of conjugates. The proof also yields invertibility
results for a new class of generalized double layer potential operators on
Lipschitz surfaces and boundedness of related Hilbert transforms.


title:
Discovery of X-ray emission from the eclipsing brown-dwarf binary 2MASS
  J05352184-0546085

abstract:
  The eclipsing brown-dwarf binary system 2MASS J05352184-0546085 is a case sui
generis. For the first time, it allows a detailed analysis of the individual
properties of young brown dwarfs, in particular, masses, and radii, and the
temperature ratio of the system components can be determined accurately. The
system shows a "temperature reversal" with the more massive component being the
cooler one, and both components are found to be active. We analyze X-ray images
obtained by Chandra and XMM-Newton containing 2MASS J05352184-0546085 in their
respective field of view. The Chandra observatory data show a clear X-ray
source at the position of 2MASS J05352184-0546085, whereas the XMM-Newton data
suffer from contamination from other nearby sources, but are consistent with
the Chandra detection. No indications of flaring activity are found in either
of the observations (together about 70 ks), and we thus attribute the observed
flux to quiescent emission. With an X-ray luminosity of 3*10^{28} erg/s we find
an L_X/L_{bol}-ratio close to the saturation limit of 10^{-3} and an
L_{X}/L_{H\alpha}-ratio consistent with values obtained from low-mass stars.
The X-ray detection of 2MASS J05352184-0546085 reported here provides
additional support for the interpretation of the temperature reversal in terms
of magnetically suppressed convection, and suggests that the activity phenomena
of young brown dwarfs resemble those of their more massive counterparts.


title:
Time-minimal control of dissipative two-level quantum systems: The
  Integrable case

abstract:
  The objective of this article is to apply recent developments in geometric
optimal control to analyze the time minimum control problem of dissipative
two-level quantum systems whose dynamics is governed by the Lindblad equation.
We focus our analysis on the case where the extremal Hamiltonian is integrable.


title:
Emergent Universe Scenario in the Einstein-Gauss-Bonnet Gravity with
  Dilaton

abstract:
  We obtain cosmological solutions which admit emergent universe (EU) scenario
in the framework of Einstein Gauss-Bonnet gravity coupled with a dilaton field
in four dimensions. The coupling parameter of the Gauss-Bonnet terms and the
dilaton in the theory are determined for obtaining an EU scenario. The
corresponding dilaton potential which admits such scenario is determined. It is
found that the Gauss- Bonnet (GB) terms coupled with a dilaton field plays an
important role in describing the dynamics of the evolution of the early as well
as the late universe. We note an interesting case where the GB term dominates
initially in the asymptotic past regime, subsequently it decreases and
thereafter its contribution in determining the dynamics of the evolution
dominates once again. We note that the Einstein static universe solution
permitted here is unstable which the asymptotic EU might follow. We also
compare our EU model with supernova data.


title:
DFB laser contribution to phase noise in an optoelectronic microwave
  oscillator

abstract:
  The optoelectronic fiber delay line microwave oscillator offers attractive
and large potential for numerous applications in high speed fiber optics
communication, space, and radar systems. Its relevant features are very low
phase noise and wide-range tunability, while operating at frequencies of tens
of GHz. We consider the contribution of the DFB laser to the oscillator phase
noise. Low frequency spectra of wavelength fluctuation and RIN are measured and
analyzed. As a conclusion, the oscillator phase noise can be improved by proper
choice of optic and optoelectronic components.


title:
Transmission phase of a quantum dot: Testing the role of population
  switching

abstract:
  We propose a controlled experiment to clarify the physical mechanism causing
phase lapses of the amplitude for electron transmission through nanoscale
devices. Such lapses are generically observed in valleys between adjacent
Coulomb--blockade peaks. The experiment involves two quantum dots embedded in
the same arm of an Aharonov--Bohm interferometer. It offers a decisive test of
"population switching", one of the leading contenders for an explanation of the
phenomenon.


title: N-flation from multiple DBI type actions

abstract:
  In this letter we present a new N-flation model constructed by making use of
multiple scalar fields which are being described by their own DBI action. We
show that the dependence of the e-folding number and of the curvature
perturbation on the number of fields changes compared with the normal N-flation
model. Our model is also quite different from the usual DBI N-flation which is
still based on one DBI action but involves many moduli components. Some
specific examples of our model have been analyzed.


title: A Dynamical Classification of the Cosmic Web

abstract:
  A dynamical classification of the cosmic web is proposed. The large scale
environment is classified into four web types: voids, sheets, filaments and
knots. The classification is based on the evaluation of the deformation tensor,
i.e. the Hessian of the gravitational potential, on a grid. The classification
is based on counting the number of eigenvalues above a certain threshold,
lambda_th at each grid point, where the case of zero, one, two or three such
eigenvalues corresponds to void, sheet, filament or a knot grid point. The
collection of neighboring grid points, friends-of-friends, of the same web
attribute constitutes voids, sheets, filaments and knots as web objects.
  A simple dynamical consideration suggests that lambda_th should be
approximately unity, upon an appropriate scaling of the deformation tensor. The
algorithm has been applied and tested against a suite of (dark matter only)
cosmological N-body simulations. In particular, the dependence of the volume
and mass filling fractions on lambda_th and on the resolution has been
calculated for the four web types. Also, the percolation properties of voids
and filaments have been studied.
  Our main findings are: (a) Already at lambda_th = 0.1 the resulting web
classification reproduces the visual impression of the cosmic web. (b) Between
0.2 < lambda_th < 0.4, a system of percolated voids coexists with a net of
interconected filaments. This suggests a reasonable choice for lambda_th as the
parameter that defines the cosmic web. (c) The dynamical nature of the
suggested classification provides a robust framework for incorporating
environmental information into galaxy formation models, and in particular the
semi-analytical ones.


title:
Probability for Primordial Black Holes in Multidimensional Universe with
  Nonlinear Scalar Curvature Terms

abstract:
  We investigate multi-dimensional universe with nonlinear scalar curvature
terms to evaluate the probability of creation of primordial black holes. For
this we obtain Euclidean instanton solution in two different topologies: (a)
$S^{D-1}$ - topology which does not accommodate primordial black holes and (b)
$S^1\times S^{D-2}$-topology which accommodates a pair of black holes. The
probability for quantum creation of an inflationary universe with a pair of
black holes has been evaluated assuming a gravitational action which is
described by a polynomial function of scalar curvature with or without a
cosmological constant ($\Lambda $) using the framework of semiclassical
approximation of Hartle-Hawking boundary conditions. We discuss here a class of
new gravitational instantons solution in the $R^4$-theory which are relevant
for cosmological model building.


title: Gas Evolution in Protoplanetary Disks

abstract:
  This article summarizes a Splinter Session at the Cool Stars XV conference in
St. Andrews with 3 review and 4 contributed talks. The speakers have discussed
various approaches to understand the structure and evolution of the gas
component in protoplanetary disks. These ranged from observational spectroscopy
in the UV, infrared and millimeter, through to chemical and hydrodynamical
models. The focus was on disks around low-mass stars, ranging from classical T
Tauri stars to transitional disks and debris disks. Emphasis was put on water
and organic molecules, the relation to planet formation, and the formation of
holes and gaps in the inner regions.


title:
Time-Minimal Control of Dissipative Two-level Quantum Systems: the
  Generic Case

abstract:
  The objective of this article is to complete preliminary results concerning
the time-minimal control of dissipative two-level quantum systems whose
dynamics is governed by Lindblad equations. The extremal system is described by
a 3D-Hamiltonian depending upon three parameters. We combine geometric
techniques with numerical simulations to deduce the optimal solutions.


title: Breakdown of the mean-field approximation in a wealth distribution model

abstract:
  One of the key socioeconomic phenomena to explain is the distribution of
wealth. Bouchaud and M\'ezard have proposed an interesting model of economy
[Bouchaud and M\'ezard (2000)] based on trade and investments of agents. In the
mean-field approximation, the model produces a stationary wealth distribution
with a power-law tail. In this paper we examine characteristic time scales of
the model and show that for any finite number of agents, the validity of the
mean-field result is time-limited and the model in fact has no stationary
wealth distribution. Further analysis suggests that for heterogeneous agents,
the limitations are even stronger. We conclude with general implications of the
presented results.

categories: q-fin.ST cond-mat.stat-mech math.DS physics.soc-ph q-fin.GN


title:
Charge Excitations in Cuprate and Nickelate in Resonant Inelastic X-Ray
  Scattering

abstract:
  We analyze the resonant inelastic x-ray scattering (RIXS) spectra at the Cu
and Ni K edges in La2CuO4 and La2NiO4, respectively. We make use of the
Keldysh-Green-function formalism, in which the RIXS intensity is described by a
product of incident-photon-dependent factor and density-density correlation
function in the 3d states. The former factor is calculated using the $4p$
density of states given by an ab initio band structure calculation and the
latter using the wavefunctions given by a Hartree-Fock calculation of a
multi-orbital tight-binding model. The initial state is described within the
Hartree-Fock approximation and the electron correlations on charge excitations
are treated within the random phase approximation. The calculated RIXS spectra
well reproduce several characteristic features in the experiments. Although
several groups have interpreted the RIXS peaks as bound excitons, our
calculation indicates that they should be interpreted as band-to-band
excitations augmented by electron correlations. The difference in RIXS spectra
between La2CuO4 and La2NiO4 is explained from this point of view.


title: Duality for a Cohen-Macaulay local ring

abstract:
  Let $(R,\fm)$ be a Cohen-Macaulay local ring. If $R$ has a canonical module,
then there are some interesting results about duality for this situation. In
this paper, we show that one can indeed obtain similar these results in the
case $R$ has not a canonical module. Also, we give some characterizations of
complete big Cohen-Macaulay modules of finite injective dimension and by using
it some characterizations of Gorenstein modules over the $\fm$-adic completion
of $R$ are obtained.


title: Unknotting genus one knots

abstract:
  For any knot with genus one and unknotting number one, other than the
figure-eight knot, we prove that there is exactly one way to unknot it by means
of a crossing change. In the case of the figure-eight knot, we prove that there
are precisely two unknotting crossing changes. The proof uses sutured manifold
theory and an analysis of the arc complex of the once-punctured torus.


title: Energetics in Condensate Star and Wormholes

abstract:
  It is known that the total gravitational energy in localized sources having
static spherical symmetry and satisfying energy conditions is negative
(attractive gravity). A natural query is how the gravitational energy behaves
under circumstances where energy conditions are violated. To answer this, the
known expression for the gravitational energy is suitably modified to account
for situations like the ones occurring in wormhole spacetime. It is then
exemplified that in many cases the modified expression yields desirable
answers. The implications are discussed.


title: The Continuum is Countable: Infinity is Unique

abstract:
  Since the theory developed by Georg Cantor, mathematicians have taken a sharp
interest in the sizes of infinite sets. We know that the set of integers is
infinitely countable and that its cardinality is Aleph0. Cantor proved in 1891
with the diagonal argument that the set of real numbers is uncountable and that
there cannot be any bijection between integers and real numbers. Cantor states
in particular the Continuum Hypothesis. In this paper, I show that the
cardinality of the set of real numbers is the same as the set of integers. I
show also that there is only one dimension for infinite sets, Aleph.


title: New Physics Searches at BaBar

abstract:
  We will present the most recent results from the BABAR Collaboration
concerning New Physics searches in rare B and Lepton Flavour Violating (LFV)
decays, including b --> s transitions, purely leptonic B decays and LFV tau
decays.


title:
Longitudinal loop integrals in the gauge invariant effective action for
  high energy QCD

abstract:
  We study integrations over light-cone degrees of freedom in the gauge
invariant effective action for high energy processes in QCD. We propose a
regularization which takes into account the signature of the reggeized gluon.
For a test we apply it to the elastic and the production amplitude.


title:
Rotation free flow of noncompressible fluid through the rotating wheel
  of centrifugal pump

abstract:
  The exact analytic solution is built for the plane flow of incompressible
fluid through the wheel with profiles of blades approximating logarithmic
spirals.


title: Black Holes and Black String-like Solutions in Codimension-2 Braneworlds

abstract:
  We discuss black hole solutions with a Gauss-Bonnet term in the bulk and an
induced gravity term on a thin brane of codimension-2. We show that these black
holes can be localized on the brane, and they can be extended further into the
bulk by a warp function. These solutions have regular horizons and no other
curvature singularities appear apart from the string-like ones. The projection
of the Gauss-Bonnet term on the brane imposes a constraint relation which
dictates the form of matter on the brane and in the bulk.


title:
Block Network Error Control Codes and Syndrome-based Complete Maximum
  Likelihood Decoding

abstract:
  In this paper, network error control coding is studied for robust and
efficient multicast in a directed acyclic network with imperfect links. The
block network error control coding framework, BNEC, is presented and the
capability of the scheme to correct a mixture of symbol errors and packet
erasures and to detect symbol errors is studied. The idea of syndrome-based
decoding and error detection is introduced for BNEC, which removes the effect
of input data and hence decreases the complexity. Next, an efficient
three-stage syndrome-based BNEC decoding scheme for network error correction is
proposed, in which prior to finding the error values, the position of the edge
errors are identified based on the error spaces at the receivers. In addition
to bounded-distance decoding schemes for error correction up to the refined
Singleton bound, a complete decoding scheme for BNEC is also introduced.
Specifically, it is shown that using the proposed syndrome-based complete
decoding, a network error correcting code with redundancy order d for receiver
t, can correct d-1 random additive errors with a probability sufficiently close
to 1, if the field size is sufficiently large. Also, a complete maximum
likelihood decoding scheme for BNEC is proposed. As the probability of error in
different network edges is not equal in general, and given the equivalency of
certain edge errors within the network at a particular receiver, the number of
edge errors, assessed in the refined Singleton bound, is not a sufficient
statistic for ML decoding.


title: Heavy quark production and spectroscopy at HERA

abstract:
  Heavy flavour production and spectroscopy are key components of the HERA
physics programme. I will summarise a selection of the recent results obtained
by the H1 and ZEUS collaborations. The production of excited charm mesons and
J/psi will be discussed as well as measurements of b quark cross-sections in
photoproduction. The status of searches for exotic bound states and the D*p
resonance will be updated.


title:
Enhanced Dust Emission in the HL Tau Disc: A Low-Mass Companion in
  Formation?

abstract:
  We have imaged the disc of the young star HL Tau using the VLA at 1.3 cm,
with 0.08" resolution (as small as the orbit of Jupiter). The disc is around
half the stellar mass, assuming a canonical gas-mass conversion from the
measured mass in large dust grains. A simulation shows that such discs are
gravitationally unstable, and can fragment at radii of a few tens of AU to form
planets. The VLA image shows a compact feature in the disc at 65 AU radius
(confirming the `nebulosity' of Welch et al. 2004), which is interpreted as a
localised surface density enhancement representing a candidate proto-planet in
its earliest accretion phase. If correct, this is the first image of a low-mass
companion object seen together with the parent disc material out of which it is
forming. The object has an inferred gas plus dust mass of approximately 14
M(Jupiter), similar to the mass of a proto-planet formed in the simulation. The
disc instability may have been enhanced by a stellar flyby: the proper motion
of the nearby star XZ Tau shows it could have recently passed the HL Tau disc
as close as ~600 AU.


title: Astrometric effects of non-uniform telescope throughput

abstract:
  In real telescopes, the optical parameters evolve with time, and the
degradation is often not uniform. This introduces variations in the image
profile and therefore photo-centre displacements which, unless corrected, may
result in astrometric errors. The effects induced on individual telescopes and
interferometric arrays are derived by numerical implementation of a range of
cases. The results are evaluated with respect to the potential impact on the
most relevant experiments for high precision astrometry in the near future,
i.e. Gaia, PRIMA and SIM, and to mitigation techniques applicable from design
stage to calibrations.


title:
New Variable Stars on Digitized Moscow Collection Plates. Field 66
  Ophiuchi (Northern Half)

abstract:
  We initiated digitization of the Moscow collection of astronomical plates
using flatbed scanners. Techniques of photographic photometry of the digital
images were applied, enabling an effective search for new variable stars. Our
search for new variables among 140000 stars in the 10 x 5 degrees northern half
of the field centered at 66 Oph, photographed with the Sternberg Institute's
40-cm astrograph in 1976--1995, gave 274 new discoveries, among them: 2
probable Population II Cepheids; 81 eclipsing variables; 5 high-amplitude Delta
Scuti stars (HADSs); 82 RR Lyr stars; 62 red irregular variables and 41 red
semiregular stars; 1 slow irregular variable not red in color. Light elements
were determined for periodic variable stars. We detected about 30 variability
suspects for follow-up CCD observations, confirmed 11 stars from the New
Catalogue of Suspected Variable Stars, and derived new light elements for 2
stars already contained in the General Catalogue of Variable Stars.


title: Higgs Boson Properties and BSM Higgs Boson Searches at LHC

abstract:
  At the end of 2008, the Large Hadron Collider (LHC) will come into operation
and the two experiments ATLAS and CMS will start taking data from proton-proton
collisions at a center-of-mass energy of \sqrt{s}=14 TeV. In preparation for
the data taking period, the discovery potential for Higgs bosons beyond the
Standard Model has been updated by both experiments and is reviewed here. In
addition, the prospects for measuring the properties of a Higgs boson like its
mass and width, its CP eigenvalues and its couplings to fermions and gauge
bosons are discussed.


title:
Inverse moments of univariate discrete distributions via the Poisson
  expansion

abstract:
  In this note we present a series expansion of inverse moments of a
non-negative discrete random variate in terms of its factorial cumulants, based
on the Poisson-Charlier expansion of a discrete distribution. We apply the
general method to the positive binomial distribution and obtain a convergent
series for its inverse moments with an error residual that is uniformly bounded
on the entire interval 0<=p<=1.


title: The low-energy spectrum of (2,0) theory on T^5 x R

abstract:
  We consider the ADE-series of (2, 0) supersymmetric quantum theories on T^5
\times R, where the first factor is a flat spatial five-torus, and the second
factor denotes time. The quantum states of such a theory \Phi are characterized
by a discrete quantum number f \in H^3 (T^5, C), where the finite abelian group
C is the center subgroup of the corresponding simply connected simply laced Lie
group G. At energies that are low compared to the inverse size of the T^5, the
spectrum consists of a set of continua of states, each of which is
characterized by the value of f and some number 5r of additional continuous
parameters. By exploiting the interpretation of this theory as the ultraviolet
completion of maximally supersymmetric Yang-Mills theory on T^4 \times S^1
\times R with gauge group G_{adj} = G/C and coupling constant g given by the
square root of the radius of the S^1 factor, one may compute the number N_f^r
(\Phi) of such continua. We perform these calculations in detail for the A- and
D-series. While the Yang-Mills theory formalism is manifestly invariant under
the \SL_4 (Z) mapping class group of T^4, the results are actually found to be
invariant under the \SL_5 (Z) mapping class group of T^5, which provides a
strong consistency check.


title:
Canonically quantized soliton in the bound state approach to heavy
  baryons in the Skyrme model

abstract:
  The bound state extension of Skyrme's topological soliton model for the heavy
baryons is quantized canonically in arbitrary reducible representations of the
SU(3) flavor group. The canonical quantization leads to an additional negative
mass term, which stabilizes the quantized soliton solution. The heavy flavor
meson in the field of the soliton is treated with semiclassical quantization.
The representation dependence of the calculated spectra for the strange, charm
and bottom baryons is explored and compared to the extant empirical spectra.


title:
Model Analysis of the $ep \to ep'\pi^+\pi^-$ Electroproduction Reaction
  on the Proton

abstract:
  Recent CLAS data on the $p\pi^+\pi^-$ electroproduction off protons at
1.3$<$W$<$1.57 GeV and 0.25$<$$Q^{2}$$<$0.6 GeV$^{2}$ have been analyzed using
a meson-baryon phenomenological model. By fitting nine 1-fold differential
cross section data for each $W$ and $Q^{2}$ bin, the charged double pion
electroproduction mechanisms are identified from their manifestations in the
observables. We have extracted the cross sections from amplitudes of each of
the considered isobar channels as well as from their coherent sum. We also
obtained non-resonant partial wave amplitudes of all contributing isobar
channels which could be useful for advancing a complete coupled-channel
analysis of all meson electroproduction data.


title: Semileptonic decays of the light J(P)=1/2(+) ground state baryon octet

abstract:
  We calculate the semileptonic baryon octet-octet transition form factors
using a manifestly Lorentz covariant quark model approach based on the
factorization of the contribution of valence quarks and chiral effects. We
perform a detailed analysis of SU(3) breaking corrections to the hyperon
semileptonic decay form factors. We present complete results on decay rates and
asymmetry parameters including lepton mass effects for the rates.


title: Systematic Distortion in Cosmic Microwave Background Maps

abstract:
  To minimize instrumentally induced systematic errors, cosmic microwave
background (CMB) anisotropy experiments measure temperature differences across
the sky using paires of horn antennas, temperature map is recovered from
temperature differences obtained in sky survey through a map-making procedure.
To inspect and calibrate residual systematic errors in recovered temperature
maps is important as most previous studies of cosmology are based on these
maps. By analyzing pixel-ring couping and latitude dependence of CMB
temperatures, we find notable systematic deviation from CMB Gaussianity in
released Wilkinson Microwave Anisotropy Probe (WMAP) maps. The detected
deviation is hard to explain by any process in the early universe and can not
be ignored for a precision cosmology study.


title:
Scaling of the giant dipole resonance widths in hot rotating nuclei from
  the ground state values

abstract:
  The systematics of the giant dipole resonance (GDR) widths in hot and
rotating nuclei are studied in terms of temperature T, angular momentum J and
mass A. The different experimental data in the temperature range of 1 - 2 MeV
have been compared with the thermal shape fluctuation model (TSFM) in the
liquid drop formalism using a modified approach to estimate the average values
of T, J and A in the decay of the compound nucleus. The values of the ground
state GDR widths have been extracted from the TSFM parametrization in the
liquid drop limit for the corrected T, J and A for a given system and compared
with the corresponding available systematics of the experimentally measured
ground state GDR widths for a range of nuclei from A = 45 to 194. Amazingly,
the nature of the theoretically extracted ground state GDR widths matches
remarkably well, though 1.5 times smaller, with the experimentally measured
ground state GDR widths consistently over a wide range of nuclei.


title:
Electronic structure of triangular, hexagonal and round graphene flakes
  near the Fermi level

abstract:
  The electronic shell structure of triangular, hexagonal and round graphene
quantum dots (flakes) near the Fermi level has been studied using a
tight-binding method. The results show that close to the Fermi level the shell
structure of a triangular flake is that of free massless particles, and that
triangles with an armchair edge show an additional sequence of levels ("ghost
states"). These levels result from the graphene band structure and the plane
wave solution of the wave equation, and they are absent for triangles with an
zigzag edge. All zigzag triangles exhibit a prominent edge state at the Fermi
level, and few low-energy conduction electron states occur both in triangular
and hexagonal flakes due to symmetry reasons. Armchair triangles can be used as
building blocks for other types of flakes that support the ghost states. Edge
roughness has only a small effect on the level structure of the triangular
flakes, but the effect is considerably enhanced in the other types of flakes.
In round flakes, the states near the Fermi level depend strongly on the flake
radius, and they are always localized on the zigzag parts of the edge.


title:
Correlated diffusion of membrane proteins and their effect on membrane
  viscosity

abstract:
  We extend the Saffman theory of membrane hydrodynamics to account for the
correlated motion of membrane proteins, along with the effect of protein
concentration on that correlation and on the response of the membrane to
stresses. Expressions for the coupling diffusion coefficients of protein pairs
and their concentration dependence are derived in the limit of small protein
size relative to the inter-protein separation. The additional role of membrane
viscosity as determining the characteristic length scale for membrane response
leads to unusual concentration effects at large separation -- the transverse
coupling increases with protein concentration, whereas the longitudinal one
becomes concentration-independent.


title: Secondary Calculus and the Covariant Phase Space

abstract:
  The covariant phase space of a Lagrangian field theory is the solution space
of the associated Euler-Lagrange equations. It is, in principle, a nice
environment for covariant quantization of a Lagrangian field theory. Indeed, it
is manifestly covariant and possesses a canonical (functional) "presymplectic
structure" w (as first noticed by Zuckerman in 1986) whose degeneracy
(functional) distribution is naturally interpreted as the Lie algebra of gauge
transformations. We propose a fully rigorous approach to the covariant phase
space in the framework of secondary calculus. In particular we describe the
degeneracy distribution of w. As a byproduct we rederive the existence of a Lie
bracket among gauge invariant functions on the covariant phase space.


title: Semileptonic Decays at Belle

abstract:
  We present three analyses based on data samples collected by the Belle
detector at the KEKB e+e- asymmetric energy collider. The first one contains
the measurement of the branching fractions and q^2 distributions of exclusive
charmless semileptonic B decays, which are used to extract the
Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}|. The sample of events is
obtained by fully reconstructing one of the B mesons in selected hadronic
modes. The second analysis determines the branching fraction and the form
factors rho^2, R_1 and R_2 for the exclusive decay B^0 -> D^{*-} \ell^+ \nu.
These measurements are used to extract the Cabibbo-Kobayashi-Maskawa matrix
element |V_{cb}|. The third analysis investigates B -> D^{**} \ell \nu decays
and determines branching ratios for the four modes D_{0}^{*}, D_{1}, D_{1}^{'}
and D_{2}^{*} for both charged and neutral B decays.


title: A Subaru Pencil-beam Search for m_R~27 Trans-neptunian bodies

abstract:
  We present the results of an archival search for Trans-neptunian objects
(TNOs) in an ecliptic field observed with Subaru in 2002. The depth of the
search allowed us to find 20 new TNOs with magnitudes between R=24 and 27. We
fit a double power law model to the data; the most likely values for the bright
and faint power law exponents are alpha_1=0.73_{-0.09}^{+0.08} and
alpha_2=0.20_{-0.14}^{+0.12}; the differential number density at R=23 is
sigma_{23}=1.46_{-0.12}^{+0.14} and the break magnitude is
R_{eq}=25.0_{-0.6}^{+0.8}. This is the most precise measurement of the break in
the TNO luminosity function to date. The break in the size distribution
corresponds to a diameter of D = 90+-30 km assuming a 4% albedo.


title: Signal-to-noise ratio of Gaussian-state ghost imaging

abstract:
  The signal-to-noise ratios (SNRs) of three Gaussian-state ghost imaging
configurations--distinguished by the nature of their light sources--are
derived. Two use classical-state light, specifically a joint signal-reference
field state that has either the maximum phase-insensitive or the maximum
phase-sensitive cross correlation consistent with having a proper $P$
representation. The third uses nonclassical light, in particular an entangled
signal-reference field state with the maximum phase-sensitive cross correlation
permitted by quantum mechanics. Analytic SNR expressions are developed for the
near-field and far-field regimes, within which simple asymptotic approximations
are presented for low-brightness and high-brightness sources. A high-brightness
thermal-state (classical phase-insensitive state) source will typically achieve
a higher SNR than a biphoton-state (low-brightness, low-flux limit of the
entangled-state) source, when all other system parameters are equal for the two
systems. With high efficiency photon-number resolving detectors, a
low-brightness, high-flux entangled-state source may achieve a higher SNR than
that obtained with a high-brightness thermal-state source.


title: Hamiltonian submanifolds of regular polytopes

abstract:
  We investigate polyhedral $2k$-manifolds as subcomplexes of the boundary
complex of a regular polytope. We call such a subcomplex {\it $k$-Hamiltonian}
if it contains the full $k$-skeleton of the polytope. Since the case of the
cube is well known and since the case of a simplex was also previously studied
(these are so-called {\it super-neighborly triangulations}) we focus on the
case of the cross polytope and the sporadic regular 4-polytopes. By our results
the existence of 1-Hamiltonian surfaces is now decided for all regular
polytopes.
  Furthermore we investigate 2-Hamiltonian 4-manifolds in the $d$-dimensional
cross polytope. These are the "regular cases" satisfying equality in Sparla's
inequality. In particular, we present a new example with 16 vertices which is
highly symmetric with an automorphism group of order 128. Topologically it is
homeomorphic to a connected sum of 7 copies of $S^2 \times S^2$. By this
example all regular cases of $n$ vertices with $n < 20$ or, equivalently, all
cases of regular $d$-polytopes with $d\leq 9$ are now decided.


title: On strong n-perfect rings

abstract:
  In this paper we introduce the notion of "strong $n$-perfect rings" which is
in some way a generalization of the notion of "$n$-perfect rings". We are
mainly concerned with those class of rings in the context of pullbacks. Also we
exhibit a class of $n$-perfect rings that are not strong $n$-perfect rings.
Finally, we establish the transfer of this notion to the direct product
notions.


title: Fine-grained state counting for black holes in loop quantum gravity

abstract:
  A state of a black hole in loop quantum gravity is given by a distribution of
spins on punctures on the horizon. The distribution is of the Boltzmann type,
with the area playing the role of the energy. In investigations where the total
area was kept approximately constant, there was a kind of thermal equilibrium
between the spins which have the same analogue temperature and the entropy was
proportional to the area. If the area is precisely fixed, however, multiple
constraints appear, different spins have different analogue temperatures and
the entropy is not strictly linear in the area, but is bounded by a linear
rise.


title: Coincidences for multiple summing mappings

abstract:
  In this note we prove new coincidence results for multiple summing mappings,
related to the cotypes of the Banach spaces involved.


title:
Deep 610-MHz Giant Metrewave Radio Telescope observations of the Spitzer
  extragalactic First Look Survey field - III. The radio properties of
  Infrared-Faint Radio Sources

abstract:
  Infrared-Faint Radio Sources (IFRSs) are a class of source which are bright
at radio frequencies, but do not appear in deep infrared images. We report the
detection of 14 IFRSs within the Spitzer extragalactic First Look Survey field,
eight of which are detected near to the limiting magnitude of a deep R-band
image of the region, at R ~ 24.5. Sensitive Spitzer Space Telescope images are
stacked in order to place upper limits on their mid-infrared flux densities,
and using recent 610-MHz and 1.4-GHz observations we find that they have
spectral indices which vary between alpha = 0.05 and 1.38, where we define
alpha such that S = S_0 nu^(- alpha), and should not be thought of as a single
source population. We place constraints on the luminosity and linear size of
these sources, and through comparison with well-studied local objects in the
3CRR catalogue demonstrate that they can be modelled as being compact (< 20
kpc) Fanaroff-Riley Class II (FRII) radio galaxies located at high redshift (z
> 4).


title:
Some irreducible representations of the braid group B_n of dimension
  greater than n

abstract:
  For any n>3, we give a family of finite dimensional irreducible
representations of the braid group B_n. Moreover, we give a subfamily
parametrized by 0<m<n of dimension the combinatoric number (n,m). The
representation obtained in the case m=1 is equivalent to the Standard
representation.


title:
On the homogeneity of global minimizers for the Mumford-Shah functional
  when K is a smooth cone

abstract:
  We show that if $(u,K)$ is a global minimizer for the Mumford-Shah functional
in $R^N$, and if K is a smooth enough cone, then (modulo constants) u is a
homogenous function of degree 1/2. We deduce some applications in $R^3$ as for
instance that an angular sector cannot be the singular set of a global
minimizer, that if $K$ is a half-plane then $u$ is the corresponding cracktip
function of two variables, or that if K is a cone that meets $S^2$ with an
union of $C^1$ curvilinear convex polygones, then it is a $P$, $Y$ or $T$.


title:
A problem in one-dimensional diffusion-limited aggregation (DLA) and
  positive recurrence of Markov chains

abstract:
  We consider the following problem in one-dimensional diffusion-limited
aggregation (DLA). At time $t$, we have an "aggregate" consisting of
$\Bbb{Z}\cap[0,R(t)]$ [with $R(t)$ a positive integer]. We also have $N(i,t)$
particles at $i$, $i>R(t)$. All these particles perform independent
continuous-time symmetric simple random walks until the first time $t'>t$ at
which some particle tries to jump from $R(t)+1$ to $R(t)$. The aggregate is
then increased to the integers in $[0,R(t')]=[0,R(t)+1]$ [so that
$R(t')=R(t)+1$] and all particles which were at $R(t)+1$ at time $t'{-}$ are
removed from the system. The problem is to determine how fast $R(t)$ grows as a
function of $t$ if we start at time 0 with $R(0)=0$ and the $N(i,0)$ i.i.d.
Poisson variables with mean $\mu>0$. It is shown that if $\mu<1$, then $R(t)$
is of order $\sqrt{t}$, in a sense which is made precise. It is conjectured
that $R(t)$ will grow linearly in $t$ if $\mu$ is large enough.


title: On Prime Ideals of Noetherian Skew Power Series Rings

abstract:
  We study prime ideals in skew power series rings $T:=R[[y;\tau,\delta]]$, for
suitably conditioned right noetherian complete semilocal rings $R$,
automorphisms $\tau$ of $R$, and $\tau$-derivations $\delta$ of $R$. These
rings were introduced by Venjakob, motivated by issues in noncommutative
Iwasawa theory. Our main results concern "Cutting Down" and "Lying Over." In
particular, under the additional assumption that $\delta = \tau - id$ (a basic
feature of the Iwasawa-theoretic context), we prove: If $I$ is an ideal of $R$,
then there exists a prime ideal $P$ of $S$ contracting to $I$ if and only if
$I$ is a $\delta$-stable $\tau$-prime ideal of $R$. Our approach essentially
depends on two key ingredients: First, the algebras considered are zariskian
(in the sense of Li and Van Oystaeyen), and so the ideals are all topologically
closed. Second, topological arguments can be used to apply previous results of
Goodearl and the author on skew polynomial rings.


title: HCN(1-0) enhancement in the bar of NGC 2903

abstract:
  We have mapped the \hcn emission from two spiral galaxies, NGC2903 and
NGC3504 to study the gas properties in the bars. The HCN(1-0) emission is
detected in the center and along the bar of NGC2903. The line ratio
HCN(1-0)/CO(1-0) ranges from 0.07 to 0.12 with the lowest value in the center.
The enhancement of HCN(1-0) emission along the bar indicates a higher fraction
of dense molecular gas in the bar than at the center. The mass of dense
molecular gas in the center (2.2x 10^7 Msun) is about 6 times lower than that
in the bar (1.2x 10^8 Msun). The total star formation rate (SFR) is estimated
to be 1.4 Msun/yr, where the SFR at the center is 1.9 times higher than that in
the bar. The time scale of consumption of the dense molecular gas in the center
is about 3x 10^7 yr which is much shorter than that in the bar of about 2 to 10
x 10^8 yr. The dynamical time scale of inflow of the gas from the bar to the
center is shorter than the consumption time scale in the bar, which suggests
that the star formation (SF) activity at the center is not deprived of fuel. In
the bar, the fraction of dense molecular gas mass relative to the total
molecular gas mass is twice as high along the leading edge than along the
central axis of the bar. The \hcn emission has a large velocity dispersion in
the bar, which can be attributed partially to the streaming motions indicative
of shocks along the bar. In NGC3504, the HCN(2-0) emission is detected only at
the center. The fraction of dense molecular gas mass in the center is about
15%. Comparison of the SFR with the predictions from numerical simulations
suggest that NGC2903 harbors a young type B bar with a strong inflow of gas
toward the center whereas NGC3504 has an older bar and has already passed the
phase of inflow of gas toward the center.


title: Non-linear regression models for Approximate Bayesian Computation

abstract:
  Approximate Bayesian inference on the basis of summary statistics is
well-suited to complex problems for which the likelihood is either
mathematically or computationally intractable. However the methods that use
rejection suffer from the curse of dimensionality when the number of summary
statistics is increased. Here we propose a machine-learning approach to the
estimation of the posterior density by introducing two innovations. The new
method fits a nonlinear conditional heteroscedastic regression of the parameter
on the summary statistics, and then adaptively improves estimation using
importance sampling. The new algorithm is compared to the state-of-the-art
approximate Bayesian methods, and achieves considerable reduction of the
computational burden in two examples of inference in statistical genetics and
in a queueing model.


title:
The Chemical Enrichment History of the Magellanic Clouds Field
  Populations

abstract:
  We report the results of our project devoted to study the chemical enrichment
history of the field population in the Magellanic Clouds using Ca II triplet
spectroscopy.


title: Decay of fidelity in terms of correlation functions

abstract:
  We consider, within the algebraic formalism, the time dependence of fidelity
for qubits encoded into an open physical system. We relate the decay of
fidelity to the evolution of correlation functions and, in the particular case
of a Markovian dynamics, to the spectral gap of the generator of the semigroup.
The results are applicable to the analysis of models of quantum memories.


title: Sampling from Dirichlet populations: estimating the number of species

abstract:
  Consider the random Dirichlet partition of the interval into $n$ fragments
with parameter $\theta >0$. We recall the unordered Ewens sampling formulae
from finite Dirichlet partitions. As this is a key variable for estimation
purposes, focus is on the number of distinct visited species in the sampling
process. These are illustrated in specific cases. We use these preliminary
statistical results on frequencies distribution to address the following
sampling problem: what is the estimated number of species when sampling is from
Dirichlet populations? The obtained results are in accordance with the ones
found in sampling theory from random proportions with Poisson-Dirichlet
distribution. To conclude with, we apply the different estimators suggested to
two different sets of real data.


title:
Eigenvalue distribution for non-self-adjoint operators on compact
  manifolds with small multiplicative random perturbations

abstract:
  In this work we extend a previous work about the Weyl asymptotics of the
distribution of eigenvalues of non-self-adjoint differential operators with
small multiplicative random perturbations, by treating the case of operators on
compact manifolds


title:
An Asymptotically Optimal RFID Authentication Protocol Against Relay
  Attacks

abstract:
  Relay attacks are a major concern for RFID systems: during an authentication
process an adversary transparently relays messages between a verifier and a
remote legitimate prover.
  We present an authentication protocol suited for RFID systems. Our solution
is the first that prevents relay attacks without degrading the authentication
security level: it minimizes the probability that the verifier accepts a fake
proof of identity, whether or not a relay attack occurs.


title:
Approximate zero-one laws and sharpness of the percolation transition in
  a class of models including two-dimensional Ising percolation

abstract:
  One of the most well-known classical results for site percolation on the
square lattice is the equation $p_c+p_c^*=1$. In words, this equation means
that for all values $\neq p_c$ of the parameter $p$, the following holds:
either a.s. there is an infinite open cluster or a.s. there is an infinite
closed "star" cluster. This result is closely related to the percolation
transition being sharp: below $p_c$, the size of the open cluster of a given
vertex is not only (a.s.) finite, but has a distribution with an exponential
tail. The analog of this result has been proven by Higuchi in 1993 for
two-dimensional Ising percolation (at fixed inverse temperature
$\beta<\beta_c$) with external field $h$, the parameter of the model. Using
sharp-threshold results (approximate zero-one laws) and a modification of an
RSW-like result by Bollob\'{a}s and Riordan, we show that these results hold
for a large class of percolation models where the vertex values can be "nicely"
represented (in a sense which will be defined precisely) by i.i.d. random
variables. We point out that the ordinary percolation model obviously belongs
to this class and we also show that the Ising model mentioned above belongs to
it.


title: Higgs Triplets, Decoupling, and Precision Measurements

abstract:
  Electroweak precision data has been extensively used to constrain models
containing physics beyond that of the Standard Model. When the model contains
Higgs scalars in representations other than SU(2) singlets or doublets, and
hence rho not equal to one at tree level, a correct renormalization scheme
requires more inputs than the three needed for the Standard Model. We discuss
the connection between the renormalization of models with Higgs triplets and
the decoupling properties of the models as the mass scale for the scalar
triplet field becomes much larger than the electroweak scale. The requirements
of perturbativity of the couplings and agreement with electroweak data place
strong restrictions on models with Higgs triplets. Our results have important
implications for Little Higgs type models and other models with rho not equal
to one at tree level.


title: Recent results from the CDMS-II experiment

abstract:
  The Cryogenic Dark Matter Search experiment (CDMS) employs low-temperature Ge
and Si detectors to detect WIMPs via their elastic scattering interaction with
the target nuclei. The current analysis of 397.8 kg-days Ge exposure resulted
in zero observed candidate events, setting an upper limit on the
spin-independent WIMP-nucleon cross-section of 6.6 x 10^{-44} cm^2 (4.6 x
10^{-44} cm^2, when previous CDMS Soudan data is included) at the 90 %
confidence level for a WIMP mass of 60 GeV. To increase the sensitivity, new
one inch thick detectors have been developed which will be used in the
SuperCDMS phase. SuperCDMS 25kg will be operated at SNOLAB with an expected
sensitivity on the spin-independent WIMP-nucleon elastic scattering
cross-section of 1 x 10^{-45} cm^2.


title: Coinductive properties of Lipschitz functions on streams

abstract:
  A simple hierarchical structure is imposed on the set of Lipschitz functions
on streams (i.e. sequences over a fixed alphabet set) under the standard
metric. We prove that sets of non-expanding and contractive functions are
closed under a certain coiterative construction. The closure property is used
to construct new final stream coalgebras over finite alphabets. For an example,
we show that the 2-adic extension of the Collatz function and certain variants
yield final bitstream coalgebras.


title:
Quantitative Stellar Spectral Classification. IV. Application to the
  Open Cluster IC 2391

abstract:
  In this work we perform the first test of a stellar spectral classification
method (Stock & Stock 1999) by applying it to early type stars. The sample of
stars are the members of the open cluster IC 2391 that have high-resolution
spectra available in the UVES Project of Paranal Observatory. We show that, in
general, absolute magnitudes $M_V$ and intrinsic colors $(B-V)_0$ can be
recovered within the uncertainties stated in the original calibration ($\sim
0.4$ for the magnitudes and $\sim 0.03$ for the colors). This accuracy allows
us to estimate distances and to infer membership of individual stars to obtain
an average distance to the cluster of $156\pm 24$ pc, which is in good
agreement with previous reported determinations. Finally, we identify and
discuss the real strengths and limitations of this method and we suggest how it
can be improved for future studies.


title:
A strongly interacting Bose gas: Nozi\`eres and Schmitt-Rink theory and
  beyond

abstract:
  We calculate the critical temperature for Bose-Einstein condensation in a gas
of bosonic atoms across a Feshbach resonance, and show how medium effects at
negative scattering lengths give rise to pairs reminiscent of the ones
responsible for fermionic superfluidity. We find that the formation of pairs
leads to a large suppression of the critical temperature. Within the formalism
developed by Nozieres and Schmitt-Rink the gas appears mechanically stable
throughout the entire crossover region, but when interactions between pairs are
taken into account we show that the gas becomes unstable close to the critical
temperature. We discuss prospects of observing these effects in a gas of
ultracold Cs133 atoms where recent measurements indicate that the gas may be
sufficiently long-lived to explore the many-body physics around a Feshbach
resonance.


title:
Giant outburst of EXO 2030+375: pulse-phase resolved analysis of
  INTEGRAL data

abstract:
  In June-September 2006 the Be/X-ray binary EXO 2030+375 experienced the
second giant outburst since its discovery. The source was shown to have a
complicated pulse-averaged X-ray spectral continuum with possible evidence of
cyclotron absorption features. In this paper we present the first pulse-phase
resolved analysis of the broad band X-ray spectra of EXO 2030+375 obtained with
the INTEGRAL observatory close to the maximum and during the decay phase of the
giant outburst. We report a strong variability of the spectrum with pulse
phase. Alternative spectral continuum models are discussed. The dependence of
the spectral parameters on pulse phase during the maximum of the outburst and
the evolution of the pulse profiles with time are qualitatively consistent with
the pulsar's emission diagram changing from the fan-beam geometry close to the
maximum of the outburst to a combination of pencil and fan beams (of comparable
intesities) at the end of the decay phase. Evidence of a cyclotron absorption
line around 63 keV at the pulse phase interval preceeding the main peak of the
pulse profile is present in the spectrum obtained close to the maximum of the
outburst.


title: Dipole models and parton saturation in ep scattering

abstract:
  In this contribution we briefly review the current status of the dipole
models and parton saturation on the basis of results presented at the HERA-LHC
workshops in the years 2006-2008. The problem of foundations of the dipole
models is addressed within the QCD formalism. Some limitations of the models
and open problems are pointed out. Furthermore, we review and compare the
currently used dipole models and summarise the applications to describe various
sets of HERA data. Finally we outline some of the theoretical approaches to the
problem of multiple scattering and saturation.


title:
Algebraic colimit calculations in homotopy theory using fibred and
  cofibred categories

abstract:
  Higher Homotopy van Kampen Theorems allow the computation as colimits of
certain homotopical invariants of glued spaces. One corollary is to describe
homotopical excision in critical dimensions in terms of induced modules and
crossed modules over groupoids. This paper shows how fibred and cofibred
categories give an overall context for discussing and computing such
constructions, allowing one result to cover many cases. A useful general result
is that the inclusion of a fibre of a fibred category preserves connected
colimits. The main homotopical application are to pairs of spaces with several
base points, but we also describe briefly the situation for triads.


title: The First Swift Ultra-Violet/Optical Telescope GRB Afterglow Catalog

abstract:
  We present the first Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray
burst (GRB) afterglow catalog. The catalog contains data from over 64,000
independent UVOT image observations of 229 GRBs first detected by Swift, the
High Energy Transient Explorer 2 (HETE2), the INTErnational Gamma-Ray
Astrophysics Laboratory (INTEGRAL), and the Interplanetary Network (IPN). The
catalog covers GRBs occurring during the period from 2005 Jan 17 to 2007 Jun 16
and includes ~86% of the bursts detected by the Swift Burst Alert Telescope
(BAT). The catalog provides detailed burst positional, temporal, and
photometric information extracted from each of the UVOT images. Positions for
bursts detected at the 3-sigma-level are provided with a nominal accuracy,
relative to the USNO-B1 catalog, of ~0.25 arcseconds. Photometry for each burst
is given in three UV bands, three optical bands, and a 'white' or open filter.
Upper limits for magnitudes are reported for sources detected below 3-sigma.
General properties of the burst sample and light curves, including the
filter-dependent temporal slopes, are also provided. The majority of the UVOT
light curves, for bursts detected at the 3-sigma-level, can be fit by a single
power-law, with a median temporal slope (alpha) of 0.96, beginning several
hundred seconds after the burst trigger and ending at ~1x10^5 s. The median
UVOT v-band (~5500 Angstroms) magnitude at 2000 s for a sample of "well"
detected bursts is 18.02. The UVOT flux interpolated to 2000 s after the burst,
shows relatively strong correlations with both the prompt Swift BAT fluence,
and the Swift X-ray flux at 11 hours after the trigger.


title:
Rate based call gapping with priorities and fairness between traffic
  classes

abstract:
  This paper presents a new rate based call gapping method. The main advantage
is that it provides maximal throughput, priority handling and fairness for
traffic classes without queues, unlike Token Bucket which provides only the
first two or Weighted Fair Queuing that uses queues. The Token Bucket is used
for call gapping because it has good throughput characteristics. For this
reason we present a mixture of the two methods keeping the good properties of
both. A mathematical model has been developed to support our proposal. It
defines the three requirements and proves theorems about if they are satisfied
with the different call gapping mechanisms. Simulation, numerical results and
statistical discussion are also presented to underpin the findings.


title: Gated combo nanodevice for sequential operations on single electron spin

abstract:
  An idea for a nanodevice in which an arbitrary sequence of three basic
quantum single qubit gates - negation, Hadamard and phase shift - can be
performed on a single electron spin. The spin state is manipulated using the
spin-orbit coupling and the electron trajectory is controlled by the electron
wave function self-focusing mechanism due to the electron interaction with the
charge induced on metal gates. We present results of simulations based on
iterative solution of the time dependent Schr\"odinger equation in which the
subsequent operations on the electron spin can be followed and controlled.
Description of the moving electron wave packet requires evaluation of the
electric field within the entire nanodevice in each time step.


title: Ergodicity breaking in strong and network-forming glassy system

abstract:
  The temperature dependence of the non-ergodicity factor of vitreous GeO$_2$,
$f_{q}(T)$, as deduced from elastic and quasi-elastic neutron scattering
experiments, is analyzed. The data are collected in a wide range of
temperatures from the glassy phase, up to the glass transition temperature, and
well above into the undercooled liquid state. Notwithstanding the investigated
system is classified as prototype of strong glass, it is found that the
temperature- and the $q$-behavior of $f_{q}(T)$ follow some of the predictions
of Mode Coupling Theory. The experimental data support the hypothesis of the
existence of an ergodic to non-ergodic transition occurring also in network
forming glassy systems.


title:
Absolutely continuous spectrum for a random potential on a tree with
  strong transverse correlations and large weighted loops

abstract:
  We consider random Schr\"odinger operators on tree graphs and prove
absolutely continuous spectrum at small disorder for two models. The first
model is the usual binary tree with certain strongly correlated random
potentials. These potentials are of interest since for complete correlation
they exhibit localization at all disorders. In the second model we change the
tree graph by adding all possible edges to the graph inside each sphere, with
weights proportional to the number of points in the sphere.


title: The warm inflationary universe

abstract:
  In the past decade, the importance of dissipation and fluctuation to
inflationary dynamics has been realized and has led to a new picture of
inflation called warm inflation. Although these phenomena are common to
condensed matter systems, for inflation models their importance has only
recently started to be appreciated. The article describes the motivation for
these phenomenon during inflation and then examines their origins from first
principles quantum field theory treatments of inflation models. Cosmology today
is a data intensive field and this is driving theory to greater precision and
predictability. This opens the possibility to consider tests for detecting
observational signatures of dissipative processes, which will be discussed. In
addition it will be discussed how particle physics and cosmology are now
working in tandem to push the boundaries of our knowledge about fundamental
physics.


title:
Similarity Renormalization Group Evolution of Many-Body Forces in a
  One-Dimensional Model

abstract:
  A one-dimensional system of bosons with short-range repulsion and mid-range
attraction is used as a laboratory to explore the evolution of many-body forces
by the Similarity Renormalization Group (SRG). The free-space SRG is
implemented for few-body systems in a symmetrized harmonic oscillator basis
using a recursive construction analogous to no-core shell model
implementations. This approach, which can be directly generalized to
three-dimensional nuclei, is fully unitary up to induced A-body forces when
applied with an A-particle basis (e.g., A-body bound-state energies are exactly
preserved). The oscillator matrix elements for a given A can then be used in
larger systems. Errors from omitted induced many-body forces show a hierarchy
of decreasing contribution to binding energies. An analysis of individual
contributions to the growth of many-body forces demonstrates such a hierarchy
and provides an understanding of its origins.


title: Enhanced stability of tetratic phase due to clustering

abstract:
  We show that the relative stability of the nematic tetratic phase with
respect to the usual uniaxial nematic phase can be greatly enhanced by
clustering effects. Two--dimensional rectangles of aspect ratio $\kappa$
interacting via hard interactions are considered, and the stability of the two
nematic phases (uniaxial and tetratic) is examined using an extended
scaled--particle theory applied to a polydispersed fluid mixture of $n$
species. Here the $i$--th species is associated with clusters of $i$
rectangles, with clusters defined as stacks of rectangles containing
approximately parallel rectangles, with frozen internal degrees of freedom. The
theory assumes an exponential cluster size distribution (an assumption fully
supported by Monte Carlo simulations and by a simple chemical--reaction model),
with fixed value of the second moment. The corresponding area distribution
presents a shoulder, and sometimes even a well-defined peak, at cluster sizes
approximately corresponding to square shape (i.e. $i\simeq\kappa$), meaning
that square clusters have a dominant contribution to the free energy of the
hard--rectangle fluid. The theory predicts an enhanced region of stability of
the tetratic phase with respect to the standard scaled--particle theory, much
closer to simulation and to experimental results, demonstrating the importance
of clustering in this fluid.


title: A robust floating nanoammeter

abstract:
  A circuit capable of measuring nanoampere currents while floating at voltages
up to at least 25kV is described. The circuit relays its output to ground
potential via an optical fiber. We particularly emphasize the design and
construction techniques which allow robust operation in the presence of high
voltage spikes and discharges.


title: Physics of Evolution: Selection without Fitness

abstract:
  Traditionally evolution is seen as a process where from a pool of possible
variations of a population (e.g. biological species or industrial goods) a few
variations get selected which survive and proliferate, whereas the others
vanish. Survival probability is typically associated with the 'fitness' of a
particular variation. In this paper we argue that the notion of fitness is an a
posteriori concept, in the sense that one can assign higher fitness to species
that survive but one can generally not derive or even measure fitness - or
fitness landscapes - per se. For this reason we think that in a 'physical'
theory of evolution such notions should be avoided. In this spirit, here we
propose a random matrix model of evolution where selection mechanisms are
encoded in the interaction matrices of species. We are able to recover some key
facts of evolution dynamics, such as punctuated equilibrium, i.e. the existence
of intrinsic large extinctions events, and, at the same time, periods of
dramatic diversification, as known e.g. from fossil records. Further, we
comment on two fundamental technical problems of a 'physics of evolution', the
non-closedness of its phase space and the problem of co-evolving boundary
conditions, apparent in all systems subject to evolution.


title: Induced gravity and gauge interactions revisited

abstract:
  It has been shown that the primary, old-fashioned idea of Sakharov's induced
gravity and gauge interactions, in the "one-loop dominance" version, works
astonishingly well yielding phenomenologically reasonable results. As a
byproduct, the issue of the role of the UV cutoff in the context of the induced
gravity has been reexamined (an idea of self-cutoff induced gravity). As an
additional check, the black hole entropy has been used in the place of the
action. Finally, it has been explicitly shown that the induced coupling
constants of gauge interactions of the standard model assume qualitatively
realistic values.


title: Spectral analyses of three carbon-enhanced metal-poor stars

abstract:
  We are conducting a high-resolution follow-up of candidate EMP stars
extracted from the Sloan Digital Sky Survey (SDSS; York et al. 2000) using UVES
at the VLT. Three of the programme stars, SDSS J0912+0216, SDSS J1036+1212 and
SDSS J1349-0229, where deliberately targetted as CEMP stars since a strong $G$
band was evident from the SDSS spectra and the weakness of the Ca {\sc ii} K
line testified their very low metallicity. The UVES high resolution follow-up
confirmed the original findings ([Fe/H] $<-2.50$) and allowed a more detailed
investigation of their chemical composition. We determined the carbon abundance
from molecular lines which form in the outer layers of the stellar atmosphere.
It is known that convection in metal-poor stars induces very low temperatures
which are not predicted by classical 1D stellar atmospheres. To obtain the
correct temperature structure, one needs full 3D hydrodynamical models. 3D
carbon abundances were determined for all three stars, using CO$^5$BOLD 3D
hydrodynamical model atmospheres. 3D effects on the carbon abundance are found
to be quite significant for these stars, with 3D corrections of up to --0.7
dex. Two of the stars, SDSS J0912+0216 and SDSS J1349-0229 exhibit an
overabundance of neutron capture elements which classifies them as CEMP-s. Star
SDSS J1036+1212, instead belongs to the elusive class of CEMP-no/s stars, with
enhanced Ba, but deficient Sr, of which it is the third member discovered to
date.


title: Tests for zero-inflation and overdispersion

abstract:
  We propose a new methodology to detect zero-inflation and overdispersion
based on the comparison of the expected sample extremes among convexly ordered
distributions. The method is very flexible and includes tests for the
proportion of structural zeros in zero-inflated models, tests to distinguish
between two ordered parametric families and a new general test to detect
overdispersion. The performance of the proposed tests is evaluated via some
simulation studies. For the well-known fetal lamb data, we conclude that the
zero-inflated Poisson model should be rejected against other more disperse
models, but we cannot reject the negative binomial model.


title:
Exciton/plasmon polaritons in GaAs/GaAlAs heterostructures near a
  metallic layer

abstract:
  We report on the strong coupling between inorganic quantum well excitons and
surface plasmons. For that purpose a corrugated silver film was deposited on
the top of a heterostructure consisting of GaAs/GaAlAs quantum wells. The
formation of plasmon/heavy-hole exciton/light-hole exciton mixed states is
demonstrated with reflectometry experiments. The interaction energies amount to
21 meV for the plasmon/light-hole exciton and 22 meV for the plasmon/heavy-hole
exciton. Some particularities of the plasmon-exciton coupling were also
discussed and qualitatively related to the plasmon polarization.


title:
A New, Efficient Stellar Evolution Code for Calculating Complete
  Evolutionary Tracks

abstract:
  We present a new stellar evolution code and a set of results, demonstrating
its capability at calculating full evolutionary tracks for a wide range of
masses and metallicities. The code is fast and efficient, and is capable of
following through all evolutionary phases, without interruption or human
intervention. It is meant to be used also in the context of modeling the
evolution of dense stellar systems, for performing live calculations for both
normal star models and merger-products.
  The code is based on a fully implicit, adaptive-grid numerical scheme that
solves simultaneously for structure, mesh and chemical composition. Full
details are given for the treatment of convection, equation of state, opacity,
nuclear reactions and mass loss.
  Results of evolutionary calculations are shown for a solar model that matches
the characteristics of the present sun to an accuracy of better than 1%; a 1
Msun model for a wide range of metallicities; a series of models of stellar
populations I and II, for the mass range 0.25 to 64 Msun, followed from
pre-main-sequence to a cool white dwarf or core collapse. An initial final-mass
relationship is derived and compared with previous studies. Finally, we briefly
address the evolution of non-canonical configurations, merger-products of
low-mass main-sequence parents.


title: Polarization measurements and their perspectives: PVLAS Phase II

abstract:
  We sketch the proposal for a "PVLAS-Phase II" experiment. The main physics
goal is to achieve the first direct observation of non-linear effects in
electromagnetism predicted by QED and the measurement of the photon-photon
scattering cross section at low energies (1-2 eV). Physical processes such as
ALP and MCP production in a magnetic field could also be accessible if
sensitive enough operation is reached. The short term experimental strategy is
to compact as much as possible the dimensions of the apparatus in order to
bring noise sources under control and to attain a sufficient sensitivity. We
will also briefly mention future pespectives, such as a scheme to implement the
resonant regeneration principle for the detection of ALPs.


title: Existence and dynamic properties of a parabolic nonlocal MEMS equation

abstract:
  Let $\Omega\subset\mathbb{R}^n$ be a $C^2$ bounded domain and $\chi>0$ be a
constant. We will prove the existence of constants
$\lambda_N\ge\lambda_N^{\ast}\ge\lambda^{\ast}(1+\chi\int_{\Omega}\frac{dx}{1-w_{\ast}})^2$
for the nonlocal MEMS equation $-\Delta
v=\lam/(1-v)^2(1+\chi\int_{\Omega}1/(1-v)dx)^2$ in $\Omega$, $v=0$ on
$\1\Omega$, such that a solution exists for any $0\le\lambda<\lambda_N^{\ast}$
and no solution exists for any $\lambda>\lambda_N$ where $\lambda^{\ast}$ is
the pull-in voltage and $w_{\ast}$ is the limit of the minimal solution of
$-\Delta v=\lam/(1-v)^2$ in $\Omega$ with $v=0$ on $\1\Omega$ as
$\lambda\nearrow \lambda^{\ast}$. We will prove the existence, uniqueness and
asymptotic behaviour of the global solution of the corresponding parabolic
nonlocal MEMS equation under various boundedness conditions on $\lambda$. We
also obtain the quenching behaviour of the solution of the parabolic nonlocal
MEMS equation when $\lambda$ is large.


title: Simplified PMT Model

abstract:
  A simplified model is proposed based on the characteristics of the
photomultiplier tube (PMT). The Model is compared to the available data, and it
successes to reproduce the saturation profile of the PMT. The model also adds
clarification about how the PMT works.


title: Semiclassical states for weakly coupled nonlinear Schr\"odinger systems

abstract:
  We consider systems of weakly coupled Schr\"odinger equations with
nonconstant potentials and we investigate the existence of nontrivial
nonnegative solutions which concentrate around local minima of the potentials.
We obtain sufficient and necessary conditions for a sequence of least energy
solutions to concentrate.


title: Hopf algebras for ternary algebras

abstract:
  We construct an universal enveloping algebra associated to the ternary
extension of Lie (super)algebras called Lie algebra of order three. A
Poincar\'e-Birkhoff-Witt theorem is proven is this context. It this then shown
that this universal enveloping algebra can be endowed with a structure of Hopf
algebra. The study of the dual of the universal enveloping algebra enables to
define the parameters of the transformation of a Lie algebra of order three. It
turns out that these variables are the variables which generate the
three-exterior algebra.


title:
Enhancement of Sensitivity-Bandwidth Product of Interferometric GW
  Detectors using White Light Cavities

abstract:
  The effect of gravitational waves (GWs) has been observed indirectly, by
monitoring the change in the orbital frequency of neutron stars in a binary
system as they lose energy via gravitational radiation. However, GWs have not
yet been observed directly. The initial LIGO apparatus has not yet observed
GWs. The Advanced LIGO (AdLIGO) will use a combination of improved techniques
in order to increase the sensitivity. Along with power recycling and a higher
power laser source, the AdLIGO will employ signal recycling (SR). While SR
would increase sensitivity, it would also reduce the bandwidth significantly.
Previously, we and others have investigated, theoretically and experimentally,
the feasibility of using a White Light Cavity (WLC) to circumvent this
constraint. However, in the previous work, it was not clear how one would
incorporate the white light cavity effect. Here, we first develop a general
model for Michelson-Interferometer based GW detectors that can be easily
adapted to include the effects of incorporating a WLC into the design. We then
describe a concrete design of a WLC constructed as a compound mirror, to
replace the signal recycling mirror. This design is simple, robust, completely
non-invasive, and can be added to the AdLIGO system without changing any other
optical elements. We show a choice of parameters for which the signal
sensitivity as well as the bandwidth are enhanced significantly over what is
planned for the AdLIGO, covering the entire spectrum of interest for
gravitational waves.


title:
The number of occurrences of a fixed spread among n directions in vector
  spaces over finite fields

abstract:
  We study a finite analog of a problem of Erdos, Hickerson and Pach on the
maximum number of occurrences of a fixed angle among n directions in
three-dimensional spaces.


title: Vertex renormalization in dc conductivity of doped chiral graphene

abstract:
  The remarkable transport properties of graphene follow not only from the the
Dirac-like energy dispersion, but also from the chiral nature of its
excitations, which makes unclear the limits of applicability of the standard
semiclassical Boltzmann approach. In this paper we provide a quantum derivation
of the transport scattering time in graphene in the case of electron-phonon
interaction. By using the Kubo formalism, we compute explicitly the vertex
corrections to the dc conductivity by retaining the full chiral matrix
structure of graphene. We show that at least in the regime of large chemical
potential the Boltzmann picture is justified, and it is also robust against a
small sublattice inequivalence which partly spoils the role of chirality.


title:
Oscillating chiral currents in nanotubes: a route to nanoscale magnetic
  test tubes

abstract:
  With a view to optimising the design of carbon-nanotube (CNT) windmills and
to maximising the internal magnetic field generated by chiral currents, we
present analytical results for the group velocity components of an electron
flux through chiral carbon nanotubes. Chiral currents are shown to exhibit a
rich behaviour and can even change sign and oscillate as the energy of the
electrons is increased. We find that the transverse velocity and associated
angular momentum of electrons is a maximum for non-metallic CNTs with a chiral
angle of 18$^o$. Such CNTs are therefore the optimal choice for CNT windmills
and also generate the largest internal magnetic field for a given longitudinal
current. For a longitudinal current of order $10^{-4}$ amps, this field can be
of order $10^{-1}$Teslas, which is sufficient to produce interesting spintronic
effects and a significant contribution to the self inductance.


title:
Inclusive and "exclusive" cross sections in the regime of multiple
  parton collisions

abstract:
  The large luminosity and the increased kinematical domain accessible at the
LHC will allow to isolate large numbers of events with multiple parton
collisions. Interestingly, the hadron is probed in different points
contemporarily in the process, which allows to obtain information on the
correlations between partons in the hadron structure. The whole experimentally
accessible information on multiple parton collisions consists in the
probability distribution of the elementary interactions, while the inclusive
cross sections, usually considered in large p_t processes, acquire a precise
statistical meaning as moments of the multiplicity distribution. Conversely
different and more "exclusive" cross sections become experimentally viable,
providing complementary information on the interaction dynamics. The matter is
discussed in details in the case of hadron-hadron collisions and the role of
parton correlations is outlined both in the inclusive and in the "exclusive"
cross sections.


title: Nonquantum Gravity

abstract:
  One of the great challenges for 21st century physics is to quantize gravity
and generate a theory that will unify gravity with the other three fundamental
forces of nature. This paper takes the (heretical) point of view that gravity
may be an inherently classical, i.e., nonquantum, phenomenon and investigates
the experimental consequences of such a model. At present there is no
experimental evidence of the quantum nature of gravity and the liklihood of
definitive tests in the future is not at all certain. If gravity is, indeed, a
nonquantum phenomenon, then it is suggested that evidence will most likely
appear at mesoscopic scales.


title:
A model for the phase separation controlled by doping and the internal
  chemical pressure in different cuprate superconductors

abstract:
  In the framework of a two-band model, we study the phase separation regime of
different kinds of strongly correlated charge carriers as a function of the
energy splitting between the two sets of bands. The narrow (wide) band
simulates the more localized (more delocalized) type of charge carriers. By
assuming that the internal chemical pressure on the CuO$_2$ layer due to
interlayer mismatch controls the energy splitting between the two sets of
states, the theoretical predictions are able to reproduce the regime of phase
separation at doping higher than 1/8 in the experimental pressure-doping-$T_c$
phase diagram of cuprates at large microstrain as it appears in overoxygenated
La$_2$CuO$_4$.


title: Light propagation in a birefringent plates with topological charge

abstract:
  We calculated the Fresnel paraxial propagator in a birefringent plate having
topological charge $q$ at its center, named "$q$-plate". We studied the change
of the beam transverse profile when it traverses the plate. An analytical
closed form of the beam profile propagating in the "$q$-plate" can be found for
many important specific input beam profiles. We paid particular attention to
the plate having a topological unit charge and we found that if small losses
due to reflection, absorption and scattering are neglected, the plate can
convert the photon spin into orbital angular momentum with up to 100%
efficiency, provided the thickness of the plate is less than the Rayleigh range
of the incident beam.


title: An elementary illustrated introduction to simplicial sets

abstract:
  This is an expository introduction to simplicial sets and simplicial homotopy
theory with particular focus on relating the combinatorial aspects of the
theory to their geometric/topological origins. It is intended to be accessible
to students familiar with just the fundamentals of algebraic topology.


title: Modeling X-ray emission from stellar coronae

abstract:
  By extrapolating from observationally derived surface magnetograms of
low-mass stars we construct models of their coronal magnetic fields and compare
the 3D field geometry with axial multipoles. AB Dor, which has a radiative
core, has a very complex field, whereas V374 Peg, which is completely
convective, has a simple dipolar field. We calculate global X-ray emission
measures assuming that the plasma trapped along the coronal loops is in
hydrostatic equilibrium and compare the differences between assuming isothermal
coronae, or by considering a loop temperature profiles. Our preliminary results
suggest that the non-isothermal model works well for the complex field of AB
Dor, but not for the simple field of V374 Peg.


title:
Probing multi-band superconductivity and magnetism in
  SmFeAsO$_{0.8}$F$_{0.2}$ single crystals by high-field vortex torque
  magnetometry

abstract:
  To probe manifestations of multiband superconductivity in oxypnictides, we
measured the angular dependence of magnetic torque $\tau(\theta)$ in the mixed
state of SmO$_{0.8}$F$_{0.2}$FeAs single crystals as functions of temperature
$T$ and high magnetic field $H$ up to 30 T. We show that the effective mass
anisotropy parameter $\gamma$ extracted from $\tau(\theta)$, can be greatly
overestimated if the strong paramagnetism of Sm or Fe ions is not properly
taken into account. The correctly extracted $\gamma$ depends on both $T$ and
$H$, saturating at $\gamma \simeq 9$ at lower temperatures. Neither the London
penetration depth nor the superfluid density is affected by high fields fields
up to the upper critical field. Our results indicate two strongly-coupled
superconducting gaps of nearly equal magnitudes.


title: The magnetic fields of accreting T Tauri stars

abstract:
  Models of magnetospheric accretion on to classical T Tauri stars often assume
that the stellar magnetic field is a simple dipole. Recent Zeeman-Doppler
imaging studies of V2129 Oph and BP Tau have shown however that their magnetic
fields are more complex. V2129 Oph is a high mass T Tauri star and despite its
young age is believed to have already developed a radiative core. In contrast
to this, the lower mass BP Tau is likely to be completely convective. As the
internal structure and therefore the magnetic field generation process is
different in both stars, it is of particular interest to compare the structure
of their magnetic fields obtained by field extrapolation from magnetic surface
maps. We compare both field structures to mulitpole magnetic fields, and
calculate the disk truncation radius for both systems. We find that by
considering magnetic fields with a realistic degree of complexity, the disk is
truncated at, or within, the radius obtained for dipole fields.


title: Signals of the QCD phase transition in core-collapse supernovae

abstract:
  We explore the implications of the QCD phase transition during the postbounce
evolution of core-collapse supernovae. Using the MIT bag model for the
description of quark matter and assuming small bag constants, we find that the
phase transition occurs during the early postbounce accretion phase. This stage
of the evolution can be simulated with general relativistic three-flavor
Boltzmann neutrino transport. The phase transition produces a second shock wave
that triggers a delayed supernova explosion. If such a phase transition happens
in a future galactic supernova, its existence and properties should become
observable as a second peak in the neutrino signal that is accompanied by
significant changes in the energy of the emitted neutrinos. In contrast to the
first neutronization burst, this second neutrino burst is dominated by the
emission of anti-neutrinos because the electron-degeneracy is lifted when the
second shock passes through the previously neutronized matter.


title: Bragg spectroscopy and Ramsey interferometry with an ultracold Fermi gas

abstract:
  We report on the observation of Bragg scattering of an ultracold Fermi gas of
6Li atoms at a dynamic optical potential. The momentum states produced in this
way oscillate in the trap for time scales on the order of seconds, nearly
unperturbed by collisions, which are absent for ultracold fermions due to the
Pauli principle. In contrast, interactions in a mixture with 87Rb atoms lead to
rapid damping. The coherence of these states is demonstrated by Ramsey-type
matter wave interferometry. The signal is improved using an echo pulse
sequence, allowing us to observe coherence times longer than 100 mus. Finally
we use Bragg spectroscopy to measure the in-situ momentum distribution of the
6Li cloud. Signatures for the degeneracy of the Fermi gas can be observed
directly from the momentum distribution of the atoms inside the trap.


title:
Effects of phase transitions in devices actuated by the electromagnetic
  vacuum force

abstract:
  We study the influence of the electromagnetic vacuum force on the behaviour
of a model device based on materials, like germanium tellurides, that undergo
fast and reversible metal-insulator transitions on passing from the crystalline
to the amorphous phase. The calculations are performed at finite temperature
and fully accounting for the behaviour of the material dielectric functions.
The results show that the transition can be exploited to extend the distance
and energy ranges under which the device can be operated without undergoing
stiction phenomena. We discuss the approximation involved in adopting the
Casimir expression in simulating nano- and micro- devices at finite
temperature.


title:
Quark matter in compact stars: astrophysical implications and possible
  signatures

abstract:
  After a brief non technical introduction of the basic properties of strange
quark matter (SQM) in compact stars, we consider some of the late important
advances in the field, and discuss some recent astrophysical observational data
that could shed new light on the possible presence of SQM in compact stars. We
show that above a threshold value of the gravitational mass a neutron star
(pure hadronic star) is metastable to the decay (conversion) to an hybrid
neutron star or to a strange star. We explore the consequences of the
metastability of "massive" neutron stars and of the existence of stable compact
"quark" stars (hybrid neutron stars or strange stars) on the concept of
limiting mass of compact stars, and we give an extension of this concept with
respect to the "classical" one given in 1939 by Oppenheimer and Volkoff.


title: Thermodynamic Limit for Spin Glasses. Beyond the Annealed Bound

abstract:
  Using a correlation inequality of Contucci and Lebowitz for spin glasses, we
demonstrate existence of the thermodynamic limit for short-ranged spin glasses,
under weaker hypotheses than previously available, namely without the
assumption of the annealed bound.


title: Transverse oscillations of systems of coronal loops

abstract:
  We study the collective kinklike normal modes of a system of several
cylindrical loops using the T-matrix theory. Loops that have similar kink
frequencies oscillate collectively with a frequency which is slightly different
from that of the individual kink mode. On the other hand, if the kink frequency
of a loop is different from that of the others, it oscillates individually with
its own frequency. Since the individual kink frequency depends on the loop
density but not on its radius for typical 1 MK coronal loops, a coupling
between kink oscillations of neighboring loops take place when they have
similar densities. The relevance of these results in the interpretation of the
oscillations studied by \citet{schrijver2000} and \citet{verwichte2004}, in
which transverse collective loop oscillations seem to be detected, is
discussed. In the first case, two loops oscillating in antiphase are observed;
interpreting this motion as a collective kink mode suggests that their
densities are roughly equal. In the second case, there are almost three groups
of tubes that oscillate with similar periods and therefore their dynamics can
be collective, which again seems to indicate that the loops of each group share
a similar density. All the other loops seem to oscillate individually and their
densities can be different from the rest.


title:
Optical and infrared flares from a transient Galactic soft gamma-ray
  repeater

abstract:
  Soft gamma-ray repeaters (SGRs) are a rare type of gamma-ray transient
sources that are ocasionally detected as bursts in the high-energy sky. They
are thought to be produced by magnetars, young neutron stars with very strong
magnetic fields of the order of 10^(14-15) G. Only three such objects are known
in our Galaxy, and a fourth one is associated with the supernova remnant N49 in
the Large Magellanic Cloud. In none of these cases has an optical counterpart
to either the gamma-ray flares or the quiescent source been identified. Here we
present multi-wavelength observations of a puzzling source, SWIFT
J195509+261406, for which we detected more than 40 flaring episodes in the
optical band over a time span of 3 days, plus a faint infrared flare 11 days
later, after which it returned to quiescence. We propose that SWIFT
J195509+261406 is a member of a subgroup of SGRs for which the long-term X-ray
emission is transient in nature. Furthermore, it is the first SGR for which
bursts have been detected in the optical and near-infrared bands and maybe the
link between the "persistent" SGRs and the dim isolated neutron stars.


title: Bounded harmonic functions for the Heckman--Opdam Laplacian

abstract:
  We describe the set of bounded harmonic functions for the Heckman--Opdam
Laplacian, when the multiplicity function is larger than 1/2. We prove that
this set is a vector space of dimension the cardinality of the Weyl group. We
give some consequences in terms of the associated hypergeometric functions.


title: Expected Coalescence Time for a Nonuniform Allocation Process

abstract:
  We give an asymptotic expression for the expected coalescence time for a
non-uniform balls-into-boxes allocation model. Connections to coalescent
processes in population biology and computer science are discussed.


title:
Exactly solvable D_N-type quantum spin models with long-range
  interaction

abstract:
  We derive the spectra of the D_N-type Calogero (rational) su(m) spin model,
including the degeneracy factors of all energy levels. By taking the strong
coupling limit of this model, in which its spin and dynamical degrees of
freedom decouple, we compute the exact partition function of the su(m)
Polychronakos-Frahm spin chain of D_N type. With the help of this partition
function we study several statistical properties of the chain's spectrum, such
as the density of energy levels and the distribution of spacings between
consecutive levels.

categories: cond-mat.str-el cond-mat.stat-mech math-ph math.MP nlin.SI


title:
Conditional probabilities with Dirac observables and the problem of time
  in quantum gravity

abstract:
  We combine the "evolving constants" approach to the construction of
observables in canonical quantum gravity with the Page--Wootters formulation of
quantum mechanics with a relational time for generally covariant systems. This
overcomes the objections levied by Kucha\v{r} against the latter formalism. The
construction is formulated entirely in terms of Dirac observables, avoiding in
all cases the physical observation of quantities that do not belong in the
physical Hilbert space. We work out explicitly the example of the parameterized
particle, including the calculation of the propagator. The resulting theory
also predicts a fundamental mechanism of decoherence.


title:
Set Theoretic Defining Equations of the Variety of Principal Minors of
  Symmetric Matrices

abstract:
  The variety of principal minors of $n\times n$ symmetric matrices, denoted
$Z_{n}$, is invariant under the action of a group $G\subset \GL(2^{n})$
isomorphic to $\G$. We describe an irreducible $G$-module of degree $4$
polynomials constructed from Cayley's $2 \times 2 \times 2$ hyperdeterminant
and show that it cuts out $Z_{n}$ set-theoretically. This solves the
set-theoretic version of a conjecture of Holtz and Sturmfels. Standard
techniques from representation theory and geometry are explored and developed
for the proof of the conjecture and may be of use for studying similar
$G$-varieties.


title:
A Unified Theory for the Cuprates, Iron-Based and Similar
  Superconducting Systems: Application for Spin and Charge Excitations in the
  Hole-Doped Cuprates

abstract:
  A unified theory for the cuprates and the iron-based superconductors is
derived on the basis of common features in their electronic structures
including quasi-two-dimensionality, and the large-U nature of the electron
orbitals close to E_F (smaller-U hybridized orbitals reside at bonding and
antibonding states away from E_F). Consequently, low-energy excitations are
described in terms of auxiliary particles, representing combinations of
atomic-like electron configurations, rather than electron-like quasiparticles.
The introduction of a Lagrange Bose field is necessary to enable the treatments
of these auxiliary particles as bosons or fermions. The condensation of the
bosons results in static or dynamical inhomogeneities, and consequently in a
commensurate or an incommensurate resonance mode. The dynamics of the fermions
determines the charge transport, and their strong coupling to the
Lagrange-field bosons results in pairing and superconductivity. The calculated
resonance mode in hole-doped cuprates agrees with the experimental results, and
is shown to be correlated with the pairing gap on the Fermi arcs.


title: D-Branes in Orientifolds and Orbifolds and Kasparov KK-Theory

abstract:
  A classification of D-branes in Type IIB Op^- orientifolds and orbifolds in
terms of Real and equivariant KK-groups is given. We classify D-branes
intersecting orientifold planes from which are recovered some special limits as
the spectrum for D-branes on top of Type I Op^- orientifold and the bivariant
classification of Type I D-branes. The gauge group and transformation
properties of the low energy effective field theory living in the corresponding
unstable D-brane system are computed by extensive use of Clifford algebras.
Some speculations about the existence of other versions of KK-groups, based on
physical insights, are proposed. In the orbifold case, some known results
concerning D-branes intersecting orbifolds are reproduced and generalized.
Finally, the gauge theory of unstable systems in these orbifolds is recovered.


title:
A finite-dimensional TQFT for three-manifolds based on group PSL(2, C)
  and cross-ratios

abstract:
  In this paper, we begin constructing a new finite-dimensional topological
quantum field theory (TQFT) for three-manifolds, based on group PSL(2,C) and
its action on a complex variable by fractional-linear transformations, by
providing its key ingredient -- a new type of chain complexes. As these
complexes happen to be acyclic often enough, we make use of their torsion to
construct different versions of manifold invariants. In particular, we show how
to construct a large set of invariants for a manifold with boundary, analogous
to the set of invariants based on Euclidean geometric values and used in a
paper by one of the authors for constructing a "Euclidean" TQFT. We show on
examples that our invariants are highly nontrivial.


title:
Simulations of a Scintillator Compton Gamma Imager for Safety and
  Security

abstract:
  We are designing an all-scintillator Compton gamma imager for use in security
investigations and remediation actions involving radioactive threat material.
To satisfy requirements for a rugged and portable instrument, we have chosen
solid scintillator for the active volumes of both the scatter and absorber
detectors. Using the BEAMnrc/EGSnrc Monte Carlo simulation package, we have
constructed models using four different materials for the scatter detector:
LaBr_3, NaI, CaF_2 and PVT. We have compared the detector performances using
angular resolution, efficiency, and image resolution. We find that while PVT
provides worse performance than that of the detectors based entirely on
inorganic scintillators, all of the materials investigated for the scatter
detector have the potential to provide performance adequate for our purposes.


title:
Strong Violation of Critical Phenomena Universality: Wang-Landau Study
  of the 2d Blume-Capel Model under Bond Randomness

abstract:
  We study the pure and random-bond versions of the square lattice
ferromagnetic Blume-Capel model, in both the first-order and second-order phase
transition regimes of the pure model. Phase transition temperatures, thermal
and magnetic critical exponents are determined for lattice sizes in the range
L=20-100 via a sophisticated two-stage numerical strategy of entropic sampling
in dominant energy subspaces, using mainly the Wang-Landau algorithm. The
second-order phase transition, emerging under random bonds from the
second-order regime of the pure model, has the same values of critical
exponents as the 2d Ising universality class, with the effect of the bond
disorder on the specific heat being well described by double-logarithmic
corrections, our findings thus supporting the marginal irrelevance of quenched
bond randomness. On the other hand, the second-order transition, emerging under
bond randomness from the first-order regime of the pure model, has a
distinctive universality class with \nu=1.30(6) and \beta/\nu=0.128(5). This
amounts to a strong violation of the universality principle of critical
phenomena, since these two second-order transitions, with different sets of
critical exponents, are between the same ferromagnetic and paramagnetic phases.
Furthermore, the latter of these two transitions supports an extensive but weak
universality, since it has the same magnetic critical exponent (but a different
thermal critical exponent) as a wide variety of two-dimensional systems. In the
conversion by bond randomness of the first-order transition of the pure system
to second order, we detect, by introducing and evaluating connectivity spin
densities, a microsegregation that also explains the increase we find in the
phase transition temperature under bond randomness.