title:
On the emptiness formation probability of the open XXZ spin-$\tf{1}{2}$
  chain

abstract:
  This paper is devoted to the study of the emptiness formation probability
$\tau\pa{m}$ of the open XXZ chain. We derive a closed form for $\tau\pa{m}$ at
$\Delta=\tf{1}{2}$ when the boundary field vanishes. Moreover we obtain its
leading asymptotics for an arbitrary boundary field at the free fermion point.
Finally, we compute the first term of the asymptotics of $\ln\pa{\tau\pa{m}}$
in the whole massless regime $-1<\Delta<1$.


title: Reduction of the Casimir force using aerogels

abstract:
  By using silicon oxide based aerogels we show numerically that the Casimir
force can be reduced several orders of magnitude, making its effect negligible
in nanodevices. This decrease in the Casimir force is also present even when
the aerogels are deposited on metallic substrates. To calculate the Casimir
force we model the dielectric function of silicon oxide aerogels using an
effective medium dielectric function such as the Clausius-Mossotti
approximation. The results show that both the porosity of the aerogel and its
thickness can be use as control parameters to reduce the magnitude of the
Casimir force.


title:
Perfect Structure of the Special Relativity, Superluminal,
  Neutrino-Photon Mass and New Entangled Interaction

abstract:
  First, some superluminal phenomena and experiments are introduced briefly.
Next, based on the basic principles of the special relativity, the Lorentz
transformation (LT) with smaller velocity and the general Lorentz
transformation (GLT) with larger velocity should be derived simultaneously by
the classification of the timelike and the spacelike intervals. In deriving LT,
an additional independent hypothesis has been used, thus the values of velocity
are restricted absolutely, and the spacelike interval is excluded. LT and GLT
are connected by the de Broglie relation. The fundamental properties of any
four-vector and the strange characteristic which these tachyons should possess
are described. The various superluminal transformations are discussed. Further,
we think that LT is unsuitable for photon and neutrino, the photon
transformation (PT) is unified for space and time. It may reasonably overcome
some existing difficulties, and cannot restrict that the rest mass of photon
and neutrino must be zero. LT, GLT and PT together form a complete structure of
the Lorentz group. Finally, we discuss that new experiments on the quantum
entangled state shown some characters, for example, coherency, nonlocality,
quantum teleportation and superluminal. Further, it should be a new fifth
interaction, and may probably apply GLT.


title:
Direct Estimation of Single- and Two-Qubit Hamiltonians and Relaxation
  Rates

abstract:
  We provide a novel approach for characterization of quantum Hamiltonian
systems via utilizing a single measurement device. Specifically, we demonstrate
how external quantum correlations can be used for Hamiltonian identification
tasks. We explicitly introduce experimental procedures for direct estimation of
single- and two-qubit Hamiltonian parameters, and also for simultaneous
estimation of transverse and longitudinal relaxation rates, using a single
Bell-state analyzer. An advantage of our method over the earlier approaches is
that it has a built-in feature which makes it suitable for partial
characterization of Hamiltonian parameters.


title: Snapshot-based Balanced Truncation for Linear Time-periodic Systems

abstract:
  We introduce an algorithm based on a method of snapshots for computing
approximate balanced truncations for discrete-time, stable, linear
time-periodic systems. By construction, this algorithm is applicable to very
high-dimensional systems, even with very high-dimensional outputs (or,
alternatively, very high-dimensional inputs). An example is shown to validate
the method.


title: Fisher's zeros of quasi-Gaussian densities of states

abstract:
  We discuss apparent paradoxes regarding the location of the zeros of the
partition function in the complex $\beta$ plane (Fisher's zeros) of a pure
SU(2) lattice gauge theory in 4 dimensions. We propose a new criterion to draw
the region of the complex $\beta$ plane where reweighting methods can be
trusted when the density of states is almost but not exactly Gaussian. We
propose new methods to infer the existence of zeros outside of this region. We
demonstrate the reliability of these proposals with quasi Gaussian Monte Carlo
distributions where the locations of the zeros can be calculated by independent
numerical methods. The results are presented in such way that the methods can
be applied for general lattice models. Applications to specific lattice models
will be discussed in a separate publication.


title: Meta-Stable Brane Configurations with Seven NS5-Branes

abstract:
  We present the intersecting brane configurations consisting of NS-branes,
D4-branes(and anti D4-branes) and O6-plane, of type IIA string theory
corresponding to the meta-stable nonsupersymmetric vacua in four dimensional
N=1 supersymmetric SU(N_c) x SU(N_c') x SU(N_c'') gauge theory with a symmetric
tensor field, a conjugate symmetric tensor field and bifundamental fields. We
also describe the intersecting brane configurations of type IIA string theory
corresponding to the nonsupersymmetric meta-stable vacua in the above gauge
theory with an antisymmetric tensor field, a conjugate symmetric tensor field,
eight fundamental flavors and bifundamentals. These brane configurations
consist of NS-branes, D4-branes(and anti D4-branes), D6-branes and O6-planes.


title:
Universality and diversity of folding mechanics for three-helix bundle
  proteins

abstract:
  In this study we evaluate, at full atomic detail, the folding processes of
two small helical proteins, the B domain of protein A and the Villin headpiece.
Folding kinetics are studied by performing a large number of ab initio Monte
Carlo folding simulations using a single transferable all-atom potential. Using
these trajectories, we examine the relaxation behavior, secondary structure
formation, and transition-state ensembles (TSEs) of the two proteins and
compare our results with experimental data and previous computational studies.
To obtain a detailed structural information on the folding dynamics viewed as
an ensemble process, we perform a clustering analysis procedure based on graph
theory. Moreover, rigorous pfold analysis is used to obtain representative
samples of the TSEs and a good quantitative agreement between experimental and
simulated Fi-values is obtained for protein A. Fi-values for Villin are also
obtained and left as predictions to be tested by future experiments. Our
analysis shows that two-helix hairpin is a common partially stable structural
motif that gets formed prior to entering the TSE in the studied proteins. These
results together with our earlier study of Engrailed Homeodomain and recent
experimental studies provide a comprehensive, atomic-level picture of folding
mechanics of three-helix bundle proteins.


title: Particle-Number Projection and the Density Functional Theory

abstract:
  In the framework of the Density Functional Theory for superconductors, we
study the restoration of the particle number symmetry by means of the
projection technique. Conceptual problems are outlined and numerical
difficulties are discussed. Both are related to the fact that neither the
many-body Hamiltonian nor the wave function of the system appear explicitly in
the Density Functional Theory. Similar obstacles are encountered in
self-consistent theories utilizing density-dependent effective interactions.


title:
Large optical gain from four-wave mixing instabilities in semiconductor
  quantum wells

abstract:
  Based on a microscopic many-particle theory, we predict large optical gain in
the probe and background-free four-wave mixing directions caused by excitonic
instabilities in semiconductor quantum wells. For a single quantum well with
radiative-decay limited dephasing in a typical pump-probe setup we discuss the
microscopic driving mechanisms and polarization and frequency dependence of
these instabilities.


title: Avoiding small subgraphs in Achlioptas processes

abstract:
  For a fixed integer r, consider the following random process. At each round,
one is presented with r random edges from the edge set of the complete graph on
n vertices, and is asked to choose one of them. The selected edges are
collected into a graph, which thus grows at the rate of one edge per round.
This is a natural generalization of what is known in the literature as an
Achlioptas process (the original version has r=2), which has been studied by
many researchers, mainly in the context of delaying or accelerating the
appearance of the giant component.
  In this paper, we investigate the small subgraph problem for Achlioptas
processes. That is, given a fixed graph H, we study whether there is an online
algorithm that substantially delays or accelerates a typical appearance of H,
compared to its threshold of appearance in the random graph G(n, M). It is easy
to see that one cannot accelerate the appearance of any fixed graph by more
than the constant factor r, so we concentrate on the task of avoiding H. We
determine thresholds for the avoidance of all cycles C_t, cliques K_t, and
complete bipartite graphs K_{t,t}, in every Achlioptas process with parameter r
>= 2.


title:
Practical scheme for non-postselection entanglement concentration using
  linear optical elements

abstract:
  We report a practical non-postselection entanglement concentration scheme in
which a maximally entangled Bell-state photon pair is produced from two pairs
of partially (or non-maximally) entangled photons. Since this scheme is built
only upon linear optical elements and does not require photon-number resolving
detectors, it has immediate applications in experimental implementations of
various quantum information protocols which require two-photon Bell-states.


title:
Large Magellanic Cloud Distance from Cepheid Variables using Least
  Squares Solutions

abstract:
  Distance to the Large Magellanic Cloud (LMC) is determined using the Cepheid
variables in the LMC. We combine the individual LMC Cepheid distances obtained
from the infrared surface brightness method and a dataset with a large number
of LMC Cepheids. Using the standard least squares method, the LMC distance
modulus can be found from the ZP offsets of these two samples. We have adopted
both a linear P-L relation and a ``broken'' P-L relation in our calculations.
The resulting LMC distance moduli are 18.48+-0.03 mag and 18.49+-0.04 mag
(random error only), respectively, which are consistent to the adopted 18.50
mag in the literature.


title: Finite dimensional Hecke algebras

abstract:
  These are notes prepared for ICRA workshop at Torun, Poland, August 2007. In
the first part, we explain results on canonical basic sets by Geck and Jacon
and propose a categorification framework which is suitable for our example of
Hecke algebras. In the second part, we review basics of Kashiwara crystal and
explain the Fock space theory of cyclotomic Hecke algebras and its
applications. In the third part, we explain Rouquier's theory of
quasihereditary covers of cyclotomic Hecke algebras. We add detailed
explanation of the proofs here. The third part is based on my intensive course
given at Nagoya university in January 2007.


title:
Scalable scheme for entangling multiple ququarts using linear optical
  elements

abstract:
  We report a scalable linear optical scheme for generating entangled states of
multiple ququarts in which the individual single-ququart state is prepared with
the biphoton polarization state of frequency-nondegenerate spontaneous
parametric down-conversion. The output state is calculated with the full
consideration of the higher order effect (double-pair events) of spontaneous
parametric down-conversion. Scalability to multiple-ququart entanglement is
demonstrated with examples: linear optical entanglement of three and four
individual biphoton ququarts.


title: An Ozsvath-Szabo Floer homology invariant of knots in a contact manifold

abstract:
  Using the knot Floer homology filtration, we define invariants associated to
a knot in a three-manifold possessing non-vanishing Floer co(homology) classes.
In the case of the Ozsvath-Szabo contact invariant we obtain an invariant of
knots in a contact three-manifold. This invariant provides an upper bound for
the Thurston-Bennequin plus rotation number of any Legendrian realization of
the knot. We use it to demonstrate the first systematic construction of prime
knots in contact manifolds other than the three-sphere with negative maximal
Thurston-Bennequin invariant. Perhaps more interesting, our invariant provides
a criterion for an open book to induce a tight contact structure. A corollary
is that if a manifold possesses contact structures with distinct non-vanishing
Ozsvath-Szabo invariants, then any fibered knot can realize the classical
Eliashberg-Bennequin bound in at most one of these contact structures.


title: Unitary Solution to a Quantum Gravity Information Paradox

abstract:
  We consider a toy model of the interaction of a qubit with an exotic
space-time containing a time-like curve. Consistency seems to require that the
global evolution of the qubit be non-unitary. Given that quantum mechanics is
globally unitary, this then is an example of a quantum gravity information
paradox. However, we show that a careful analysis of the problem in the
Heisenberg picture reveals an underlying unitarity, thus resolving the paradox.


title: Second Order Quasi-Normal Mode of the Schwarzschild Black Hole

abstract:
  We formulate and calculate the second order quasi-normal modes (QNMs) of a
Schwarzschild black hole (BH). Gravitational wave (GW) from a distorted BH, so
called ringdown, is well understood as QNMs in general relativity. Since QNMs
from binary BH mergers will be detected with high signal-to-noise ratio by GW
detectors, it is also possible to detect the second perturbative order of QNMs,
generated by nonlinear gravitational interaction near the BH. In the BH
perturbation approach, we derive the master Zerilli equation for the metric
perturbation to second order and explicitly regularize it at the horizon and
spatial infinity. We numerically solve the second order Zerilli equation by
implementing the modified Leaver's continued fraction method. The second order
QNM frequencies are found to be twice the first order ones, and the GW
amplitude is up to $\sim 10%$ that of the first order for the binary BH
mergers. Since the second order QNMs always exist, we can use their detections
(i) to test the nonlinearity of general relativity, in particular the no-hair
theorem, (ii) to remove fake events in the data analysis of QNM GWs and (iii)
to measure the distance to the BH.


title:
s-wave Superconductivity Phase Diagram in the Inhomogeneous
  Two-Dimensional Attractive Hubbard Model

abstract:
  We study s-wave superconductivity in the two-dimensional square lattice
attractive Hubbard Hamiltonian for various inhomogeneous patterns of
interacting sites. Using the Bogoliubov-de Gennes (BdG) mean field
approximation, we obtain the phase diagram for inhomogeneous patterns in which
the on-site attractive interaction U_i between the electrons takes on two
values, U_i=0 and -U/(1-f) (with f the concentration of non-interacting sites)
as a function of average electron occupation per site n, and study the
evolution of the phase diagram as f varies. In certain regions of the phase
diagram, inhomogeneity results in a larger zero temperature average pairing
amplitude (order parameter) and also a higher superconducting (SC) critical
temperature T_c, relative to a uniform system with the same mean interaction
strength (U_i=-U on all sites). These effects are observed for stripes,
checkerboard, and even random patterns of the attractive centers, suggesting
that the pattern of inhomogeneity is unimportant. The phase diagrams also
include regions where superconductivity is obliterated due to the formation of
various charge ordered phases. The enhancement of T_{c} due to inhomogeneity is
robust as long as the electron doping per site n is less than twice the
fraction of interacting sites [2(1-f)] regardless of the pattern. We also show
that for certain inhomogeneous patterns, when n = 2(1-f), increasing
temperature can work against the stability of existing charge ordered phases
for large f and as a result, enhance T_{c}.


title:
Stieltjes like functions and inverse problems for systems with
  Schr\"odinger operator

abstract:
  A class of scalar Stieltjes like functions is realized as linear-fractional
transformations of transfer functions of conservative systems based on a
Schr\"odinger operator T_h in $L_2[a,+\infty)$ with a non-selfadjoint boundary
condition. In particular it is shown that any Stieltjes function of this class
can be realized in the unique way so that the main operator $\bA$ of a system
is an accretive (*)-extension of a Schr\"odinger operator T_h. We derive
formulas that restore the system uniquely and allow to find the exact value of
a non-real parameter h in the definition of T_h as well as a real parameter
$\mu$ that appears in the construction of the elements of the realizing system.
An elaborate investigation of these formulas shows the dynamics of the restored
parameters h and $\mu$ in terms of the changing free term $\gamma$ from the
integral representation of the realizable function. It turns our that the
parametric equations for the restored parameter h represent different circles
whose centers and radii are determined by the realizable function. Similarly,
the behavior of the restored parameter $\mu$ are described by hyperbolas.


title: Adaptively Biased Molecular Dynamics for Free Energy Calculations

abstract:
  We present an Adaptively Biased Molecular Dynamics (ABMD) method for the
computation of the free energy surface of a reaction coordinate using
non-equilibrium dynamics. The ABMD method belongs to the general category of
umbrella sampling methods with an evolving biasing potential, and is inspired
by the metadynamics method. The ABMD method has several useful features,
including a small number of control parameters, and an $O(t)$ numerical cost
with molecular dynamics time $t$. The ABMD method naturally allows for
extensions based on multiple walkers and replica exchange, where different
replicas can have different temperatures and/or collective variables. This is
beneficial not only in terms of the speed and accuracy of a calculation, but
also in terms of the amount of useful information that may be obtained from a
given simulation. The workings of the ABMD method are illustrated via a study
of the folding of the Ace-GGPGGG-Nme peptide in a gaseous and solvated
environment.


title: Accurate measurement of the D0-D0bar mixing parameters

abstract:
  We propose a new method to determine the mass and width differences of the
two D meson mass-eigenstates as well as the CP violating parameters associated
with D^0-\bar{D}^0 mixing. We show that an accurate measurement of all the
mixing parameters is possible for an arbitrary CP violating phase, by combining
observables from a time dependent study of D decays to a doubly Cabibbo
suppressed mode with information from a CP eigenstate. As an example we
consider D^0-> K^{*0} \pi^0 decays where the K^{*0} is reconstructed in both
K^+\pi^- and K_S\pi^0. We also show that decays to the CP eigenstate D-> K^+K^-
together with D-> K^+\pi^- can be used to extract all the mixing parameters. A
combined analysis using D^0-> K^{*0} \pi^0 and D-> K^+K^- can also be used to
reduce the ambiguity in the determination of parameters.


title:
Nonlocal Charge Transport Mediated by Spin Diffusion in the Spin-Hall
  Effect Regime

abstract:
  A nonlocal electric response in the spin-Hall regime, resulting from spin
diffusion mediating charge conduction, is predicted. The spin-mediated
transport stands out due to its long-range character, and can give dominant
contribution to nonlocal resistance. The characteristic range of nonlocality,
set by the spin diffusion length, can be large enough to allow detection of
this effect in materials such as GaAs despite its small magnitude. The
detection is facilitated by a characteristic nonmonotonic dependence of
transresistance on the external magnetic field, exhibiting sign changes and
decay.


title:
Rheological Behavior of Aqueous Suspensions of Laponite: New Insights
  into the Ageing Phenomena

abstract:
  In this paper, ageing behavior of suspensions of laponite with varying salt
concentration is investigated using rheological tools. It is observed that the
ageing is accompanied by an increase in the complex viscosity. The succeeding
creep experiments performed at various ages showed damped oscillations in the
strain. The characteristic time-scale of the damped oscillations, retardation
time, showed a prominent decrease with the age of the system. However, this
dependence weakens with an increase in the salt concentration, which is known
to change microstructure of the system from glass-like to gel-like. We
postulate that a decrease in the retardation time can be represented as a
decrease in the viscosity (friction) of the dissipative environment surrounding
the arrested entities that opposes elastic deformation of the system. We
believe that ageing in colloidal glass leads to a greater ordering that
enhances relative spacing between the constituents thereby reducing the
frictional resistance. However, since a gel state is inherently different in
structure (fractal network) than that of a glass (disordered), ageing in the
same does not induce ordering. Consequently, we observe inverse dependence of
retardation time on age becoming weaker with an increase in the salt
concentration. We analyze these results from a perspective of ageing dynamics
of both glass state and gel state of laponite suspensions.


title: The Principle of Relativity and Inertial Dragging

abstract:
  Machs principle and the principle of relativity have been discussed by H. I.
Hartman and C. Nissim-Sabat in this journal. Several phenomena were said to
violate the principle of relativity as applied to rotating motion. These claims
have recently been contested. However, in neither of these articles have the
general relativistic phenomenon of inertial dragging been invoked, and no
calculation have been offered by either side to substantiate their claims. Here
I discuss the possible validity of the principle of relativity for rotating
motion within the context of the general theory of relativity, and point out
the significance of inertial dragging in this connection. Although my main
points are of a qualitative nature, I also provide the necessary calculations
to demonstrate how these points come out as consequences of the general theory
of relativity


title: Aspects of CP violation in the HZZ coupling at the LHC

abstract:
  We examine the CP-conserving (CPC) and CP-violating (CPV) effects of a
general HZZ coupling through a study of the process H -> ZZ* -> 4 leptons at
the LHC. We construct asymmetries that directly probe these couplings. Further,
we present complete analytical formulae for the angular distributions of the
decay leptons and for some of the asymmetries. Using these we have been able to
identify new observables which can provide enhanced sensitivity to the CPV $H
ZZ$ coupling. We also explore probing CP violation through shapes of
distributions in different kinematic variables, which can be used for Higgs
bosons with mH < 2 mZ.


title: Formation of Deeply Bound Kaonic Atoms in (K^-,N) Reactions

abstract:
  We study theoretically the (K^-,N) reactions for the formation of the deeply
bound kaonic atoms, which were predicted to be quasi--stable with narrow
widths, using the Green function method. We consider various cases with
different target nuclei and energies systematically and find the clear signals
in the theoretical spectra for all cases considered in this article. The
signals show very interesting structures, such as the $RESONANCE DIP$ instead
of the resonance peak. We discuss the origins of the interesting structures and
possibilities to get new information on the existence of the kaonic nuclei from
the spectra of the atomic state formations.


title: Quasi-bound states in continuum

abstract:
  We report the prediction of quasi-bound states (resonant states with very
long lifetimes) that occur in the eigenvalue continuum of propagating states
for a wide region of parameter space. These quasi-bound states are generated in
a quantum wire with two channels and an adatom, when the energy bands of the
two channels overlap. A would-be bound state that lays just below the upper
energy band is slightly destabilized by the lower energy band and thereby
becomes a resonant state with a very long lifetime (a second QBIC lays above
the lower energy band).


title:
A cryogenic amplifier for fast real-time detection of single-electron
  tunneling

abstract:
  We employ a cryogenic High Electron Mobility Transistor (HEMT) amplifier to
increase the bandwidth of a charge detection setup with a quantum point contact
(QPC) charge sensor. The HEMT is operating at 1K and the circuit has a
bandwidth of 1 MHz. The noise contribution of the HEMT at high frequencies is
only a few times higher than that of the QPC shot noise. We use this setup to
monitor single-electron tunneling to and from an adjacent quantum dot and we
measure fluctuations in the dot occupation as short as 400 nanoseconds, 20
times faster than in previous work.


title: Asymptotics for sliced average variance estimation

abstract:
  In this paper, we systematically study the consistency of sliced average
variance estimation (SAVE). The findings reveal that when the response is
continuous, the asymptotic behavior of SAVE is rather different from that of
sliced inverse regression (SIR). SIR can achieve $\sqrt{n}$ consistency even
when each slice contains only two data points. However, SAVE cannot be
$\sqrt{n}$ consistent and it even turns out to be not consistent when each
slice contains a fixed number of data points that do not depend on n, where n
is the sample size. These results theoretically confirm the notion that SAVE is
more sensitive to the number of slices than SIR. Taking this into account, a
bias correction is recommended in order to allow SAVE to be $\sqrt{n}$
consistent. In contrast, when the response is discrete and takes finite values,
$\sqrt{n}$ consistency can be achieved. Therefore, an approximation through
discretization, which is commonly used in practice, is studied. A simulation
study is carried out for the purposes of illustration.


title:
Strong spin-orbit induced Gilbert damping and g-shift in iron-platinum
  nanoparticles

abstract:
  The shape of ferromagnetic resonance spectra of highly dispersed, chemically
disordered Fe_{0.2}Pt_{0.8} nanospheres is perfectly described by the solution
of the Landau-Lifshitz-Gilbert (LLG) equation excluding effects by crystalline
anisotropy and superparamagnetic fluctuations. Upon decreasing temperature, the
LLG damping $\alpha(T)$ and a negative g-shift, g(T)-g_0, increase proportional
to the particle magnetic moments determined from the Langevin analysis of the
magnetization isotherms. These novel features are explained by the scattering
of the $q \to 0$ magnon from an electron-hole (e/h) pair mediated by the
spin-orbit coupling, while the sd-exchange can be ruled out. The large
saturation values, $\alpha(0)=0.76$ and $g(0)/g_0-1=-0.37$, indicate the
dominance of an overdamped 1 meV e/h-pair which seems to originate from the
discrete levels of the itinerant electrons in the d_p=3 nm nanoparticles.


title: Impedance measurement technique for quantum systems

abstract:
  The impedance measurement technique consists in that the phase-dependent
(parametric) inductance of the system is probed by the classical tank circuit
via measuring the voltage. The notion of the parametric inductance for the
impedance measurement technique is revisited for the case when a quantum system
is probed. Measurement of the quantum state of the system of superconducting
circuits (qubits) is studied theoretically. It is shown that the result of the
measurement is defined by the partial energy levels populations in the qubits.


title: On the total curvatures of a tame function

abstract:
  Given a definable function f, enough differentiable, we study the continuity
of the total curvature function t --> K(t), total curvature of the level {f=t},
and the total absolute curvature function t-->|K| (t), total absolute curvature
of the level {f=t}. We show they admits at most finitely many discontinuities.


title: Methodology and convergence rates for functional linear regression

abstract:
  In functional linear regression, the slope ``parameter'' is a function.
Therefore, in a nonparametric context, it is determined by an infinite number
of unknowns. Its estimation involves solving an ill-posed problem and has
points of contact with a range of methodologies, including statistical
smoothing and deconvolution. The standard approach to estimating the slope
function is based explicitly on functional principal components analysis and,
consequently, on spectral decomposition in terms of eigenvalues and
eigenfunctions. We discuss this approach in detail and show that in certain
circumstances, optimal convergence rates are achieved by the PCA technique. An
alternative approach based on quadratic regularisation is suggested and shown
to have advantages from some points of view.


title: Charm production in diffractive DIS and PHP at ZEUS

abstract:
  The ZEUS experiment has measured charm production in diffractive DIS and in
photoproduction. The data are in agreement with perturbative QCD calculations
based on various parameterisations of diffractive parton distribution
functions. The results are consistent with QCD factorisation in diffractive DIS
and direct photoproduction.


title: Direct observation of excitonic polaron in InAs/GaAs quantum dots

abstract:
  Excitonic polaron is directly demonstrated for the first time in InAs/GaAs
quantum dots with photoluminescence method. A new peak ($s'$) below the ground
state of exciton ($s$) comes out as the temperature varies from 4.2 K to 285 K,
and a huge anticrossing energy of 31 meV between $s'$ and $s$ is observed at
225 K, which can only be explained by the formation of excitonic polaron. The
results also provide a strong evidence for the invalidity of Huang-Rhys
formulism in dealing with carrier-longitudinal optical phonon interaction in
quantum dot. Instead, we propose a simple two-band model, and it fits the
experimental data quite well. The reason for the finding of the anticrossing is
also discussed.


title:
Modified brane cosmologies with induced gravity, arbitrary matter
  content and a Gauss-Bonnet term in the bulk

abstract:
  We extend the covariant analysis of the brane cosmological evolution in order
to take into account, apart from a general matter content and an
induced-gravity term on the brane, a Gauss-Bonnet term in the bulk. The
gravitational effect of the bulk matter on the brane evolution can be described
in terms of the total bulk mass as measured by a bulk observer at the location
of the brane. This mass appears in the effective Friedmann equation through a
term characterized as generalized dark radiation that induces mirage effects in
the evolution. We discuss the normal and self-accelerating branches of the
combined system. We also derive the Raychaudhuri equation that can be used in
order to determine if the cosmological evolution is accelerating.


title: Entanglement of superposition and pair coherent states

abstract:
  Entanglement characteristics of a pair coherent state is studied using
entanglement of superposition. It is demonstrated only few states in the
expansion of a pair coherent state, in a harmonic oscillator basis, contribute
significantly to the entanglement. We also study a case of two superposed pair
coherent states


title: Quantile regression with varying coefficients

abstract:
  Quantile regression provides a framework for modeling statistical quantities
of interest other than the conditional mean. The regression methodology is well
developed for linear models, but less so for nonparametric models. We consider
conditional quantiles with varying coefficients and propose a methodology for
their estimation and assessment using polynomial splines. The proposed
estimators are easy to compute via standard quantile regression algorithms and
a stepwise knot selection algorithm. The proposed Rao-score-type test that
assesses the model against a linear model is also easy to implement. We provide
asymptotic results on the convergence of the estimators and the null
distribution of the test statistic. Empirical results are also provided,
including an application of the methodology to forced expiratory volume (FEV)
data.


title: Supernova rates and stellar populations

abstract:
  We discuss the results about the nature of type Ia Supernovae that can be
derived by studying their rates in different stellar populations. While the
evolution of SN photometry and spectra can constrain the explosion mechanism,
the SN rate depends on the progenitor system. We review the current available
data on rates as a function of parent galaxy color, morphology, star formation
rate, radio luminosity and environment. By studying the variation of the rates
with the color of the parent galaxy, a strong evidence was established that
type Ia SNe come from both young and old stars. The dependence of the rates
with the radio power of the parent galaxy is best reproduced by a bimodal
distribution of delay time between the formation of the progenitor and its
explosion as a SN. Cluster early-type galaxies show higher type Ia SN rate with
respect to field galaxies, and this effect can be due either to traces of young
stars or to differences in the delay time distribution.


title: Cygnus X-3 transition from the ultrasoft to the hard state

abstract:
  Aims: The nature of Cygnus X-3 is still not understood well. This binary
system might host a black hole or a neutron star. Recent observations by
INTEGRAL have shown that Cygnus X-3 was again in an extremely ultrasoft state.
Here we present our analysis of the transition from the ultrasoft state,
dominated by blackbody radiation at soft X-rays plus non-thermal emission in
the hard X-rays, to the low hard state.
  Methods: INTEGRAL observed Cyg X-3 six times during three weeks in late May
and early June 2007. Data from IBIS/ISGRI and JEM-X1 were analysed to show the
spectral transition.
  Results: During the ultrasoft state, the soft X-ray spectrum is
well-described by an absorbed (NH = 1.5E22 1/cm**2) black body model, whereas
the X-ray spectrum above 20 keV appears to be extremely low and hard (Gamma =
1.7). During the transition, the radio flux rises to a level of >1 Jy, and the
soft X-ray emission drops by a factor of 3, while the hard X-ray emission rises
by a factor of 14 and becomes steeper (up to Gamma = 4).
  Conclusions: The ultrasoft state apparently precedes the emission of a jet,
which is apparent in the radio and hard X-ray domain.


title: Asymptotic data analysis on manifolds

abstract:
  Given an m-dimensional compact submanifold $\mathbf{M}$ of Euclidean space
$\mathbf{R}^s$, the concept of mean location of a distribution, related to mean
or expected vector, is generalized to more general $\mathbf{R}^s$-valued
functionals including median location, which is derived from the spatial
median. The asymptotic statistical inference for general functionals of
distributions on such submanifolds is elaborated. Convergence properties are
studied in relation to the behavior of the underlying distributions with
respect to the cutlocus. An application is given in the context of independent,
but not identically distributed, samples, in particular, to a multisample
setup.


title: Non-perturbative vacuum-polarization effects in proton-laser collisions

abstract:
  In the collision of a high-energy proton beam and a strong laser field,
merging of the laser photons can occur due to the polarization of vacuum. The
probability of photon merging is calculated by accounting exactly for the laser
field and presents a highly non-perturbative dependence on the laser intensity
and frequency. It is shown that the non-perturbative vacuum-polarization
effects can be experimentally measured by combining the next-generation of
table-top petawatt lasers with presently available proton accelerators.


title:
Electroweak corrections to hadronic production of W bosons at large
  transverse momenta

abstract:
  To match the precision of present and future measurements of W-boson
production at hadron colliders electroweak radiative corrections must be
included in the theory predictions. In this paper we consider their effect on
the transverse momentum (p_T) distribution of W bosons, with emphasis on large
p_T. We evaluate the full electroweak O(alpha) corrections to the processes pp
-> W+jet and p\bar p -> W+jet including virtual and real photonic
contributions. We present the explicit expressions in analytical form for the
virtual corrections and provide results for the real corrections, discussing in
detail the treatment of soft and collinear singularities. We also provide
compact approximate expressions which are valid in the high-energy region,
where the electroweak corrections are strongly enhanced by logarithms of
\hat{s}/M_W^2. These expressions describe the complete asymptotic behaviour at
one loop as well as the leading and next-to-leading logarithms at two loops.
Numerical results are presented for proton-proton collisions at 14 TeV and
proton-antiproton collisions at 2 TeV. The corrections are negative and their
size increases with p_T. At the LHC, where transverse momenta of 2 TeV or more
can be reached, the one- and two-loop corrections amount up to -40% and +10%,
respectively, and will be important for a precise analysis of W production. At
the Tevatron, transverse momenta up to 300 GeV are within reach. In this case
the electroweak corrections amount up to -10% and are thus larger than the
expected statistical error.


title: Optimal Subgroups and Applications to Nilpotent Elements

abstract:
  Let G be a reductive group acting on an affine variety X, let x in X be a
point whose G-orbit is not closed, and let S be a G-stable closed subvariety of
X which meets the closure of the G-orbit of x but does not contain x. In this
paper, we study G.R. Kempf's optimal class Omega_G(x,S) of cocharacters of G
attached to the point x; in particular, we consider how this optimality
transfers to subgroups of G.
  Suppose K is a G-completely reducible subgroup of G which fixes x, and let H
= C_G(K)^0. Our main result says that the H-orbit of x is also not closed, and
the optimal class Omega_H(x,S) for H simply consists of the cocharacters in
Omega_G(x,S) which evaluate in H. We apply this result in the case that G acts
on its Lie algebra via the adjoint representation to obtain some new
information about cocharacters associated with nilpotent elements in good
characteristic.


title:
QLib - A Matlab Package for Quantum Information Theory Calculations with
  Applications

abstract:
  Developing intuition about quantum information theory problems is difficult,
as is verifying or ruling-out of hypothesis. We present a Matlab package
intended to provide the QIT community with a new and powerful tool-set for
quantum information theory calculations. The package covers most of the "QI
textbook" and includes novel parametrization of quantum objects and a robust
optimization mechanism. New ways of re-examining well-known results is
demonstrated. QLib is designed to be further developed and enhanced by the
community and is available for download at www.qlib.info


title:
Bose-Einstein condensates in 1D optical lattices: nonlinearity and
  Wannier-Stark spectra

abstract:
  We present our experimental investigations on the subject of
nonlinearity-modified Bloch-oscillations and of nonlinear Landau-Zener
tunneling between two energy bands in a rubidium Bose Einstein condensate in an
accelerated periodic potential. Nonlinearity introduces an asymmetry in
Landau-Zener tunneling. We also present measurements of resonantly enhanced
tunneling between the Wannier-Stark energy levels for Bose-Einstein condensates
loaded into an optical lattice.


title: Projective modules over discrete Hodge algebras

abstract:
  Let A be a Noetherian commutative ring. Assume that projective modules of
rank r over polynomial extensions of A are extended from A. Then projective
modules of rank r over discrete Hodge A-algebras are also extended from A. This
result extends a result of T. Vorst.


title: Outlier robust corner-preserving methods for reconstructing noisy images

abstract:
  The ability to remove a large amount of noise and the ability to preserve
most structure are desirable properties of an image smoother. Unfortunately,
they usually seem to be at odds with each other; one can only improve one
property at the cost of the other. By combining M-smoothing and
least-squares-trimming, the TM-smoother is introduced as a means to unify
corner-preserving properties and outlier robustness. To identify edge- and
corner-preserving properties, a new theory based on differential geometry is
developed. Further, robustness concepts are transferred to image processing. In
two examples, the TM-smoother outperforms other corner-preserving smoothers. A
software package containing both the TM- and the M-smoother can be downloaded
from the Internet.


title: Harmonicity in N=4 supersymmetry and its quantum anomaly

abstract:
  The holomorphicity property of N=1 superpotentials or of N=2 F-terms
involving vector multiplets is generalized to the case of N=4 1/2-BPS effective
operators defined in harmonic superspace. The resulting harmonicity equations
are shown to control the moduli dependence of the couplings of higher
dimensional operators involving powers of the N=4 Weyl superfield, computed by
N=4 topological amplitudes. These equations can also be derived on the string
side, exhibiting an anomaly from world-sheet boundary contributions that leads
to recursion relations for the non-analytic part of the couplings.


title: Inflation and the semiclassical dynamics of a conformal scalar field

abstract:
  We derive the semiclassical evolution of massless conformally coupled scalar
matter in the de Sitter space-time from the Born-Oppenheimer reduction of the
Wheeler-DeWitt equation. We find a remarkable difference with respect to the
minimally coupled case: the effect of the quantum gravitational corrections do
not depend on the momentum of the scalar mode up to second order in the Planck
length and, therefore, there are no relevant corrections to the dispersion
relation.


title:
Determination of light quark masses from the electromagnetic splitting
  of pseudoscalar meson masses computed with two flavors of domain wall
  fermions

abstract:
  We determine the light quark masses from lattice QCD simulations
incorporating the electromagnetic interaction of valence quarks. The meson
masses are calculated on lattice QCD configurations generated by the RBC
Collaboration for two flavors of dynamical domain wall fermions, which are
combined with QED configurations generated via quenched non-compact lattice
QED. The electromagnetic part of the pion mass splitting is found to be
$m_{\pi^+}-m_{\pi^0}=4.12(21)$ MeV, where only the statistical error is quoted,
and similarly for the kaon, 1.443(55) MeV. Our results for the light quark
masses are $m_u^{\rm\bar{MS}}$(2 GeV)=$3.02(27)(19)$ MeV, $m_d^{\rm\bar{MS}}$(2
GeV)=$5.49(20)(34)$ MeV, and $m_s^{\rm\bar{MS}}$(2 GeV)=$119.5(56)(74)$ MeV,
where the first error is statistical and the second systematic. By averaging
over $\pm e$ to cancel ${\cal O}(e)$ noise exactly on each combined gauge field
configuration, we are able to work at physical $\alpha=1/137$ and obtain very
small statistical errors. In our calculation, several sources of systematic
error remain, including finite volume, non-zero lattice spacing, chiral
extrapolation, quenched QED, and quenched strange quark, which may be more
significant than the errors quoted above.


title:
Asymptotic local efficiency of Cram\'{e}r--von Mises tests for
  multivariate independence

abstract:
  Deheuvels [J. Multivariate Anal. 11 (1981) 102--113] and Genest and
R\'{e}millard [Test 13 (2004) 335--369] have shown that powerful rank tests of
multivariate independence can be based on combinations of asymptotically
independent Cram\'{e}r--von Mises statistics derived from a M\"{o}bius
decomposition of the empirical copula process. A result on the large-sample
behavior of this process under contiguous sequences of alternatives is used
here to give a representation of the limiting distribution of such test
statistics and to compute their relative local asymptotic efficiency. Local
power curves and asymptotic relative efficiencies are compared under familiar
classes of copula alternatives.


title: Self-similar Radiation from Numerical Rosenau-Hyman Compactons

abstract:
  The numerical simulation of compactons, solitary waves with compact support,
is characterized by the presence of spurious phenomena, as numerically-induced
radiation, which is illustrated here using four numerical methods applied to
the Rosenau-Hyman K(p,p) equation. Both forward and backward radiations are
emitted from the compacton presenting a self-similar shape which has been
illustrated graphically by the proper scaling. A grid refinement study shows
that the amplitude of the radiations decreases as the grid size does,
confirming its numerical origin. The front velocity and the amplitude of both
radiations have been studied as a function of both the compacton and the
numerical parameters. The amplitude of the radiations decreases exponentially
in time, being characterized by a nearly constant scaling exponent. An ansatz
for both the backward and forward radiations corresponding to a self-similar
function characterized by the scaling exponent is suggested by the present
numerical results.


title: Lifshitz asymptotics for Hamiltonians monotone in the randomness

abstract:
  In various aspects of the spectral analysis of random Schroedinger operators
monotonicity with respect to the randomness plays a key role. In particular,
both the continuity properties and the low energy behaviour of the integrated
density of states (IDS) are much better understood if such a monotonicity is
present in the model than if not.
  In this note we present Lifshitz-type bounds on the IDS for two classes of
random potentials. One of them is a slight generalisation of a model for which
a Lifshitz bound was derived in a recent joint paper with Werner Kirsch [KV].
The second one is a breather type potential which is a sum of characteristic
functions of intervals. Although the second model is very simple, it seems that
it cannot be treated by the methods of [KV]. The models and the proofs are
motivated by well-established methods developed for so called alloy type
potentials.


title:
Effect of geometrical size of the particles in a hot and dense hadron
  gas

abstract:
  Incorporation of the finite size of baryons into the equation of state (EOS)
of a hot and dense hadron gas (HG) in a thermodynamically consistent manner has
been a much studied problem. We first review its current status. Various models
have been proposed in order to account for the repulsive force generated by the
hard-core geometrical size of the baryons resulting in an excluded volume
effect in the EOS. We examine the criterion of the thermodynamical consistency
of these models and summarize their shortcomings. In order to remove the
shortcomings, we propose a new model which incorporates the excluded volume
effect in a thermodynamically consistent manner. We find that the new model
works even for the cases of extremely large temperatures and densities where
most of other approaches fail. Furthermore, the new expressions for
thermodynamical variables resemble in form with those obtained from
thermodynamically inconsistent models and thus a useful correction factor has
been suggested here which converts inconsistent expressions into
thermodynamically consistent ones. Finally we compare the predictions of new
model with those obtained from various old models.


title: Steady state statistics of driven diffusions

abstract:
  We consider overdamped diffusion processes driven out of thermal equilibrium
and we analyze their dynamical steady fluctuations. We discuss the
thermodynamic interpretation of the joint fluctuations of occupation times and
currents; they incorporate respectively the time-symmetric and the
time-antisymmetric sector of the fluctuations. We highlight the canonical
structure of the joint fluctuations. The novel concept of traffic complements
the entropy production for the study of the occupation statistics. We explain
how the occupation and current fluctuations get mutually coupled out of
equilibrium. Their decoupling close-to-equilibrium explains the validity of
entropy production principles.


title:
The Chrono-Geometrical Structure of General Relativity and Clock
  Synchronization

abstract:
  After a review of the chrono-geometrical structure of special relativity,
where the definition of the instantaneous 3-space is based on the
observer-dependent convention for the synchronization of distant clocks, it is
shown that in a class of models of general relativity the instantaneous 3-space
and the associated clock synchronization convention are dynamically determined
by Einstein's equations. This theoretical framework is necessary to understand
the relativistic effects around the Earth, to be tested with the ACES mission
of ESA, and the implications for metrology induced by the accuracy of the new
generation of atomic clocks.


title: Convergence rates of posterior distributions for noniid observations

abstract:
  We consider the asymptotic behavior of posterior distributions and Bayes
estimators based on observations which are required to be neither independent
nor identically distributed. We give general results on the rate of convergence
of the posterior measure relative to distances derived from a testing
criterion. We then specialize our results to independent, nonidentically
distributed observations, Markov processes, stationary Gaussian time series and
the white noise model. We apply our general results to several examples of
infinite-dimensional statistical models including nonparametric regression with
normal errors, binary regression, Poisson regression, an interval censoring
model, Whittle estimation of the spectral density of a time series and a
nonlinear autoregressive model.


title:
Brownian motion in a non-homogeneous force field and photonic force
  microscope

abstract:
  The Photonic Force Microscope (PFM) is an opto-mechanical technique based on
an optical trap that can be assumed to probe forces in microscopic systems.
This technique has been used to measure forces in the range of pico- and
femto-Newton, assessing the mechanical properties of biomolecules as well as of
other microscopic systems. For a correct use of the PFM, the force field to
measure has to be invariable (homogeneous) on the scale of the Brownian motion
of the trapped probe. This condition implicates that the force field must be
conservative, excluding the possibility of a rotational component. However,
there are cases where these assumptions are not fulfilled Here, we show how to
improve the PFM technique in order to be able to deal with these cases. We
introduce the theory of this enhanced PFM and we propose a concrete analysis
workflow to reconstruct the force field from the experimental time-series of
the probe position. Furthermore, we experimentally verify some particularly
important cases, namely the case of a conservative or rotational force-field.


title: Simple Stringy Dynamical SUSY Breaking

abstract:
  We present simple string models which dynamically break supersymmetry without
non-Abelian gauge dynamics. The Fayet model, the Polonyi model, and the
O'Raifeartaigh model each arise from D-branes at a specific type of
singularity. D-brane instanton effects generate the requisite exponentially
small scale of supersymmetry breaking.


title:
Comment on the paper "Energy Loss of Charm Quarks in the Quark-Gluon
  Plasma : Collisional vs Radiative"

abstract:
  In the article by M. G. Mustafa published in Phys. Rev. C {\bf 72}, 014905
(2005) the author has estimated the total energy loss of a charm quark and
quenching of hadron spectra due to the collisional energy loss of energetic
partons in an expanding quark-gluon plasma employing Fokker-Planck equation. We
wish to point out through this Comment that some of conceptual and numerical
results of the said paper are unreliable. For the sake of clarity our
discussion will focus on the massless case (although a few remarks on the
$m\neq 0$ case are also made).


title: Virtual Manufacturing : Tools for improving Design and Production

abstract:
  The research area "Virtual Manufacturing" can be defined as an integrated
manufacturing environment which can enhance one or several levels of decision
and control in manufacturing process. Several domains can be addressed: Product
and Process Design, Process and Production Planning, Machine Tool, Robot and
Manufacturing System. As automation technologies such as CAD/CAM have
substantially shortened the time required to design products, Virtual
Manufacturing will have a similar effect on the manufacturing phase thanks to
the modelling, simulation and optimisation of the product and the processes
involved in its fabrication.


title:
Stochastic resonance and heat fluctuations in a driven double-well
  system

abstract:
  We study a periodically driven (symmetric as well as asymmetric)double-well
potential system at finite temperature. We show that mean heat loss by the
system to the environment(bath) per period of the applied field is a good
quantifier of stochastic resonance. It is found that the heat fluctuations over
a single period are always larger than the work fluctuations. The observed
distributions of work and heat exhibit pronounced asymmetry near resonance. The
heat losses over a large number of periods satisfies the conventional
steady-state fluctuation theorem, though different relation exists for this
quantity.


title: Lattice-switch Monte Carlo for binary hard-sphere crystals

abstract:
  We show how to generalize the Lattice Switch Monte Carlo method to calculate
the phase diagram of a binary system. A global coordinate transformation is
combined with a modification of particle diameters, enabling the
multi-component system in question to be explored and directly compared to a
suitable reference state in a single Monte Carlo simulation. We use the method
to evaluate the free energies of binary hard sphere crystals. Calculations at
moderate size ratios, \alpha=0.58 and \alpha=0.73, are in agreement with
previous results, and confirm AB2 and AB13 as stable structures. We also find
that the AB(CsCl) structure is not entropically stable at the size ratio and
volume at which it has been reported experimentally, and therefore that those
observations cannot be explained by packing effects alone.


title:
Orbital Evolution of an Accreting Millisecond Pulsar: Witnessing the
  Banquet of a Hidden Black Widow?

abstract:
  We have performed a timing analysis of all the four X-ray outbursts from the
accreting millisecond pulsar SAX J1808.4-3658 observed so far by the PCA on
board RXTE. For each of the outbursts we derived the best-fit value of the time
of ascending node passage. We find that these times follow a parabolic trend,
which gives an orbital period derivative $\dot P_{\rm orb} = (3.40 \pm 0.18)
\times 10^{-12}$ s/s, and a refined estimate of the orbital period, $P_{\rm
orb} = 7249.156499 \pm 1.8 \times 10^{-5}$ s (reference epoch $T_0 =
50914.8099$ MJD). This derivative is positive, suggesting a degenerate or fully
convective companion star, but is more than one order of magnitude higher than
what is expected from secular evolution driven by angular momentum losses
caused by gravitational radiation under the hypothesis of conservative mass
transfer. Using simple considerations on the angular momentum of the system, we
propose an explanation of this puzzling result assuming that during X-ray
quiescence the source is ejecting matter (and angular momentum) from the inner
Lagrangian point. We have also verified that this behavior is in agreement with
a possible secular evolution of the system under the hypothesis of highly
non-conservative mass transfer. In this case, we find stringent constraints on
the masses of the two components of the binary system and its inclination. The
proposed orbital evolution indicates that in this kind of sources the neutron
star is capable to efficiently ablate the companion star, suggesting that this
kind of objects are part of the population of the so-called black widow
pulsars, still visible in X-rays during transient mass accretion episodes.


title: Inference for mixtures of symmetric distributions

abstract:
  This article discusses the problem of estimation of parameters in finite
mixtures when the mixture components are assumed to be symmetric and to come
from the same location family. We refer to these mixtures as semi-parametric
because no additional assumptions other than symmetry are made regarding the
parametric form of the component distributions. Because the class of symmetric
distributions is so broad, identifiability of parameters is a major issue in
these mixtures. We develop a notion of identifiability of finite mixture
models, which we call k-identifiability, where k denotes the number of
components in the mixture. We give sufficient conditions for k-identifiability
of location mixtures of symmetric components when k=2 or 3. We propose a novel
distance-based method for estimating the (location and mixing) parameters from
a k-identifiable model and establish the strong consistency and asymptotic
normality of the estimator. In the specific case of L_2-distance, we show that
our estimator generalizes the Hodges--Lehmann estimator. We discuss the
numerical implementation of these procedures, along with an empirical estimate
of the component distribution, in the two-component case. In comparisons with
maximum likelihood estimation assuming normal components, our method produces
somewhat higher standard error estimates in the case where the components are
truly normal, but dramatically outperforms the normal method when the
components are heavy-tailed.


title: Zeta functions that hear the shape of a Riemann surface

abstract:
  To a compact hyperbolic Riemann surface, we associate a finitely summable
spectral triple whose underlying topological space is the limit set of a
corresponding Schottky group, and whose ``Riemannian'' aspect (Hilbert space
and Dirac operator) encode the boundary action through its Patterson-Sullivan
measure. We prove that the ergodic rigidity theorem for this boundary action
implies that the zeta functions of the spectral triple suffice to characterize
the (anti-)conformal isomorphism class of the corresponding Riemann surface.
Thus, you can hear the shape of a Riemann surface, by listening to a suitable
spectral triple.


title: FSR1767 - a new globular cluster in the Galaxy

abstract:
  The globular cluster (GC) nature of the recently catalogued candidate FSR
1767 is established in the present work. It results as the closest GC so far
detected in the Galaxy. The nature of this object is investigated by means of
2MASS colour-magnitude diagrams (CMDs), the stellar radial density profile
(RDP) and proper-motions (PM). The properties are consistent with an
intermediate metallicity ($\feh\approx-1.2$) GC with a well-defined turnoff
(TO), red-giant branch (RGB) and blue horizontal-branch (HB). The distance of
FSR 1767 from the Sun is $\ds\approx1.5$ kpc, and it is located at the
Galactocentric distance $\rgc\approx5.7$ kpc. With the space velocity
components $(V,W)=(184\pm14,-43\pm14)\rm km s^{-1}$, FSR 1767 appears to be a
Palomar-like GC with $\mv\approx-4.7$, that currently lies $\approx57$ pc below
the Galactic plane. The RDP is well represented by a King profile with the core
and tidal radii $\rc=0.24\pm0.08$ pc and $\rt=3.1\pm1.0$ pc, respectively, with
a small half-light radius $\rh=0.60\pm0.15$ pc. The optical absorption is
moderate for an infrared GC, $A_V=6.2\pm0.3$, which together with its central
direction and enhanced contamination explains why it has so far been
overlooked.


title: Neutron Stars in a Chiral Model with Finite Temperature

abstract:
  Neutron star matter is investigated in a hadronic chiral model approach using
the lowest flavor-SU(3) multiplets for baryons and mesons. The parameters are
determined to yield consistent results for saturated nuclear matter as well as
for finite nuclei. The influence of baryonic resonances is discussed. The
global properties of a neutron star such as its mass and radius are determined.
Proto-neutron star properties are studied by taking into account trapped
neutrinos, temperature and entropy effects.


title: Nonparametric estimation in a nonlinear cointegration type model

abstract:
  We derive an asymptotic theory of nonparametric estimation for a time series
regression model $Z_t=f(X_t)+W_t$, where \ensuremath\{X_t\} and
\ensuremath\{Z_t\} are observed nonstationary processes and $\{W_t\}$ is an
unobserved stationary process. In econometrics, this can be interpreted as a
nonlinear cointegration type relationship, but we believe that our results are
of wider interest. The class of nonstationary processes allowed for $\{X_t\}$
is a subclass of the class of null recurrent Markov chains. This subclass
contains random walk, unit root processes and nonlinear processes. We derive
the asymptotics of a nonparametric estimate of f(x) under the assumption that
$\{W_t\}$ is a Markov chain satisfying some mixing conditions. The
finite-sample properties of $\hat{f}(x)$ are studied by means of simulation
experiments.


title: The pattern speeds of NGC 6946

abstract:
  We study the kinematics of the barred spiral galaxy NGC 6946 by investigating
the velocity field from H-alpha Fabry-Perot observations, determined the
pattern speed of the bar by using the Tremaine-Weinberg method, and find a main
pattern speed of 21.7 (+4.0,-0.8) km/s/kpc. Our data clearly suggest the
presence of an additional pattern with a pattern speed more than twice that of
the large pattern in this galaxy. We use the epicycle approximation to deduce
the location of the resonance radii and subsequently determine the pattern
speed between the radii, and find that inside the inner Inner Lindblad
Resonance radius, a bar-like system has evolved.


title:
A preliminary analysis on metaheuristics methods applied to the
  Haplotype Inference Problem

abstract:
  Haplotype Inference is a challenging problem in bioinformatics that consists
in inferring the basic genetic constitution of diploid organisms on the basis
of their genotype. This information allows researchers to perform association
studies for the genetic variants involved in diseases and the individual
responses to therapeutic agents.
  A notable approach to the problem is to encode it as a combinatorial problem
(under certain hypotheses, such as the pure parsimony criterion) and to solve
it using off-the-shelf combinatorial optimization techniques. The main methods
applied to Haplotype Inference are either simple greedy heuristic or exact
methods (Integer Linear Programming, Semidefinite Programming, SAT encoding)
that, at present, are adequate only for moderate size instances.
  We believe that metaheuristic and hybrid approaches could provide a better
scalability. Moreover, metaheuristics can be very easily combined with problem
specific heuristics and they can also be integrated with tree-based search
techniques, thus providing a promising framework for hybrid systems in which a
good trade-off between effectiveness and efficiency can be reached.
  In this paper we illustrate a feasibility study of the approach and discuss
some relevant design issues, such as modeling and design of approximate solvers
that combine constructive heuristics, local search-based improvement strategies
and learning mechanisms. Besides the relevance of the Haplotype Inference
problem itself, this preliminary analysis is also an interesting case study
because the formulation of the problem poses some challenges in modeling and
hybrid metaheuristic solver design that can be generalized to other problems.


title: Nonparametric estimation when data on derivatives are available

abstract:
  We consider settings where data are available on a nonparametric function and
various partial derivatives. Such circumstances arise in practice, for example
in the joint estimation of cost and input functions in economics. We show that
when derivative data are available, local averages can be replaced in certain
dimensions by nonlocal averages, thus reducing the nonparametric dimension of
the problem. We derive optimal rates of convergence and conditions under which
dimension reduction is achieved. Kernel estimators and their properties are
analyzed, although other estimators, such as local polynomial, spline and
nonparametric least squares, may also be used. Simulations and an application
to the estimation of electricity distribution costs are included.


title:
Notes on bias and covariance matrix of the angular power spectrum on
  small sky maps

abstract:
  We compute the effects induced by the use of small CMB maps on the
measurement of the $\cl{l}$ coefficients of the angular power spectrum and show
that small systematic effects have to be taken into account. We also compute
numerically the cosmic variance and covariance of the $\cl{l}$ spectrum for
various spherical cap like maps. Comparisons with simulations are presented.
The calculations are done using the standard method based on the spherical
harmonic transform or using the temperature angular correlation spectrum.


title:
Single hole and vortex excitations in the doped Rokhsar-Kivelson quantum
  dimer model on the triangular lattice

abstract:
  We consider the doped Rokhsar-Kivelson quantum dimer model on the triangular
lattice with one mobile hole (monomer) at the Rokhsar-Kivelson point. The
motion of the hole is described by two branches of excitations: the hole may
either move with or without a trapped Z2 vortex (vison). We perform a study of
the hole dispersion in the limit where the hole hopping amplitude is much
smaller than the interdimer interaction. In this limit, the hole without vison
moves freely and has a tight-binding spectrum. On the other hand, the hole with
a trapped vison is strongly constrained due to interference effects and can
only move via higher-order virtual processes.


title: Flat Energy histogram version for Interacting Growth Walk

abstract:
  Interacting Growth Walks is a recently proposed stochastic model for studying
the coil-globule transition of linear polymers. We propose a flat energy
histogram version for Interacting Growth Walk. We demonstrate the algorithm on
two dimensional square and triangular lattices by calculating the density of
energy states of Interacting Self Avoiding Walks.


title:
Transient and asymptotic behaviour of small three-dimensional
  perturbations applied to a growing wake

abstract:
  This paper has been withdrawn by the authors, as it has been rejected in
November 2007.


title:
Wigner's Dynamical Transition State Theory in Phase Space: Classical and
  Quantum

abstract:
  A quantum version of transition state theory based on a quantum normal form
(QNF) expansion about a saddle-centre-...-centre equilibrium point is
presented. A general algorithm is provided which allows one to explictly
compute QNF to any desired order. This leads to an efficient procedure to
compute quantum reaction rates and the associated Gamov-Siegert resonances. In
the classical limit the QNF reduces to the classical normal form which leads to
the recently developed phase space realisation of Wigner's transition state
theory. It is shown that the phase space structures that govern the classical
reaction d ynamicsform a skeleton for the quantum scattering and resonance
wavefunctions which can also be computed from the QNF. Several examples are
worked out explicitly to illustrate the efficiency of the procedure presented.


title: On representing claims for coherent risk measures

abstract:
  We consider the problem of representing claims for coherent risk measures.
For this purpose we introduce the concept of (weak and strong) time-consistency
with respect to a portfolio of assets, generalizing the one defined by Delbaen.
  In a similar way we extend the notion of m-stability, by introducing weak and
strong versions. We then prove that the two concepts of m-stability and
time-consistency are still equivalent, thus giving necessary and sufficient
conditions for a coherent risk measure to be represented by a market with
proportional transaction costs. We go on to deduce that, under a separability
assumption, any coherent risk measure is strongly time-consistent with respect
to a suitably chosen countable portfolio, and show the converse: that any
market with proportional transaction costs is equivalent to a market priced by
a coherent risk measure, essentially establishing the equivalence of the two
concepts.


title:
Critical Behavior in the Gravitational Collapse of a Scalar Field with
  Angular Momentum in Spherical Symmetry

abstract:
  We study the critical collapse of a massless scalar field with angular
momentum in spherical symmetry. In order to mimic the effects of angular
momentum we perform a sum of the stress-energy tensors for all the scalar
fields with the same eigenvalue, l, of the angular momentum operator and
calculate the equations of motion for the radial part of these scalar fields.
We have found that the critical solutions for different values of l are
discretely self-similar (as in the original l=0 case). The value of the
discrete, self-similar period, Delta_l, decreases as l increases in such a way
that the critical solution appears to become periodic in the limit. The mass
scaling exponent, gamma_l, also decreases with l.


title: Invariants of genus 2 mutants

abstract:
  Pairs of genus 2 mutant knots can have different Homfly polynomials, for
example some 3-string satellites of Conway mutant pairs. We give examples which
have different Kauffman 3-variable polynomials, answering a question raised by
Dunfield et al in their study of genus 2 mutants. While pairs of genus 2 mutant
knots have the same Jones polynomial, given from the Homfly polynomial by
setting v=s^2, we give examples whose Homfly polynomials differ when v=s^3. We
also give examples which differ in a Vassiliev invariant of degree 7, in
contrast to satellites of Conway mutant knots.


title:
Measurement of the current-phase relation of superconducting atomic
  contacts

abstract:
  We have probed the current-phase relation of an atomic contact placed with a
tunnel junction in a small superconducting loop. The measurements are in
quantitative agreement with the predictions of a resistively shunted SQUID
model in which the Josephson coupling of the contact is calculated using the
independently determined transmissions of its conduction channels.


title:
Deformation Quantization of Poisson Structures Associated to Lie
  Algebroids

abstract:
  In the present paper we explicitly construct deformation quantizations of
certain Poisson structures on E^*, where E -> M is a Lie algebroid. Although
the considered Poisson structures in general are far from being regular or even
symplectic, our construction gets along without Kontsevich's formality theorem
but is based on a generalized Fedosov construction. As the whole construction
merely uses geometric structures of E we also succeed in determining the
dependence of the resulting star products on these data in finding appropriate
equivalence transformations between them. Finally, the concreteness of the
construction allows to obtain explicit formulas even for a wide class of
derivations and self-equivalences of the products. Moreover, we can show that
some of our products are in direct relation to the universal enveloping algebra
associated to the Lie algebroid. Finally, we show that for a certain class of
star products on E^* the integration with respect to a density with vanishing
modular vector field defines a trace functional.


title:
Perturbed preconditioned inverse iteration for operator eigenvalue
  problems with applications to adaptive wavelet discretization

abstract:
  In this paper we discuss an abstract iteration scheme for the calculation of
the smallest eigenvalue of an elliptic operator eigenvalue problem. A short and
geometric proof based on the preconditioned inverse iteration (PINVIT) for
matrices [Knyazev and Neymeyr, (2009)] is extended to the case of operators. We
show that convergence is retained up to any tolerance if one only uses
approximate applications of operators which leads to the perturbed
preconditioned inverse iteration (PPINVIT). We then analyze the Besov
regularity of the eigenfunctions of the Poisson eigenvalue problem on a
polygonal domain, showing the advantage of an adaptive solver to uniform
refinement when using a stable wavelet base. A numerical example for PPINVIT,
applied to the model problem on the L-shaped domain, is shown to reproduce the
predicted behaviour.


title: C^*-algebraic approach to the Bose-Hubbard model

abstract:
  We give a new derivation of the variational formula for the pressure of the
long-range-hopping Bose-Hubbard model, which was first proved in \cite{BD}. The
proof is analogous to that of a theorem on noncommutative large deviations
introduced by Petz, Raggio and Verbeure \cite{PRV} and could similarly be
extended to more general Bose system of mean-field type. We apply this
formalism to prove Bose-Einstein condensation for the case of small coupling.


title:
Hazard models with varying coefficients for multivariate failure time
  data

abstract:
  Statistical estimation and inference for marginal hazard models with varying
coefficients for multivariate failure time data are important subjects in
survival analysis. A local pseudo-partial likelihood procedure is proposed for
estimating the unknown coefficient functions. A weighted average estimator is
also proposed in an attempt to improve the efficiency of the estimator. The
consistency and asymptotic normality of the proposed estimators are established
and standard error formulas for the estimated coefficients are derived and
empirically tested. To reduce the computational burden of the maximum local
pseudo-partial likelihood estimator, a simple and useful one-step estimator is
proposed. Statistical properties of the one-step estimator are established and
simulation studies are conducted to compare the performance of the one-step
estimator to that of the maximum local pseudo-partial likelihood estimator. The
results show that the one-step estimator can save computational cost without
compromising performance both asymptotically and empirically and that an
optimal weighted average estimator is more efficient than the maximum local
pseudo-partial likelihood estimator. A data set from the Busselton Population
Health Surveys is analyzed to illustrate our proposed methodology.


title:
Euler equations are not exactly controllable by a finite-dimensional
  external force

abstract:
  We show that the Euler system is not exactly controllable by a
finite-dimensional external force. The proof is based on the comparison of the
Kolmogorov epsilon-entropy for Holder spaces and for the class of functions
that can be obtained by solving the 2D Euler equations with various right-hand
sides.


title: Measuring a Kaluza-Klein radius smaller than the Planck length

abstract:
  Hestenes has shown that a bispinor field on a Minkowski space-time is
equivalent to an orthonormal tetrad of one-forms together with a complex scalar
field. More recently, the Dirac and Einstein equations were unified in a tetrad
formulation of a Kaluza-Klein model which gives precisely the usual
Dirac-Einstein Lagrangian. In this model, Dirac's bispinor equation is obtained
in the limit for which the radius of higher compact dimensions of the
Kaluza-Klein manifold becomes vanishingly small compared with the Planck
length. For a small but finite radius, the Kaluza-Klein model predicts velocity
splitting of single fermion wave packets. That is, the model predicts a single
fermion wave packet will split into two wave packets with slightly different
group velocities. Observation of such wave packet splits would determine the
size of the Kaluza-Klein radius. If wave packet splits were not observed in
experiments with currently achievable accuracies, the Kaluza-Klein radius would
be at least twenty five orders of magnitude smaller than the Planck length.


title:
Quasi-stationary distributions as centrality measures of reducible
  graphs

abstract:
  Random walk can be used as a centrality measure of a directed graph. However,
if the graph is reducible the random walk will be absorbed in some subset of
nodes and will never visit the rest of the graph. In Google PageRank the
problem was solved by introduction of uniform random jumps with some
probability. Up to the present, there is no clear criterion for the choice this
parameter. We propose to use parameter-free centrality measure which is based
on the notion of quasi-stationary distribution. Specifically we suggest four
quasi-stationary based centrality measures, analyze them and conclude that they
produce approximately the same ranking. The new centrality measures can be
applied in spam detection to detect ``link farms'' and in image search to find
photo albums.


title: Energy relaxation in the spin-polarized disordered electron liquid

abstract:
  The energy relaxation in the spin-polarized disordered electron systems is
studied in the diffusive regime. We derived the quantum kinetic equation in
which the kernel of electron-electron collision integral explicitly depends on
the electron magnetization. As the consequence, the inelastic scattering rate
is found to have non-monotonic dependence on the spin polarization of the
electron system.


title:
Admixture of an s-wave component to the d-wave gap symmetry in
  high-temperature superconductors

abstract:
  Neutron crystal-field spectroscopy experiments in the Y- and La-type
high-temperature superconductors HoBa2Cu3O6.56, HoBa2Cu4O8, and
La1.81Sr0.15Ho0.04CuO4 are reviewed. By this bulk-sensitive technique,
information on the gap function is obtained from the relaxation behavior of
crystal-field transitions associated with the Ho3+ ions which sit as local
probes close to the superconducting copper-oxide planes. The relaxation data
exhibit a peculiar change from a convex to a concave shape between the
superconducting transition temperature Tc and the pseudogap temperature T*
which can only be modelled satisfactorily if the gap function of predominantly
d-wave symmetry includes an s-wave component of the order of 20-25%,
independent of the doping level. Moreover, our results are compatible with an
unusual temperature dependence of the gap function in the pseudogap region
(Tc<T<T*), i.e., a breakup of the Fermi surface into disconnected arcs.


title:
Noether symmetry approach to scalar-field-dominated cosmology with
  dynamically evolving G and Lambda

abstract:
  This paper studies the cosmological equations for a scalar field Phi in the
framework of a quantum gravity modified Einstein--Hilbert Lagrangian where G
and Lambda are dynamical variables. It is possible to show that there exists a
Noether symmetry for the point Lagrangian describing this scheme in a FRW
universe. Our main result is that the Noether Symmetry Approach fixes both
Lambda = Lambda(G) and the potential V = V(Phi) of the scalar field. The method
does not lead, however, to easily solvable equations, by virtue of the higher
dimensionality of the reduced configuration space involved, the additional
variable being the running Newton coupling.


title: Microscopic derivation of Frenkel excitons in second quantization

abstract:
  Starting from the microscopic hamiltonian describing free electrons in a
periodic lattice, we derive the hamiltonian appropriate to Frenkel excitons.
This is done through a grouping of terms different from the one leading to
Wannier excitons. This grouping makes appearing the atomic states as a relevant
basis to describe Frenkel excitons in the second quantization. Using them, we
derive the Frenkel exciton creation operators as well as the commutators which
rule these operators and which make the Frenkel excitons differing from
elementary bosons. The main goal of the present paper is to provide the
necessary grounds for future works on Frenkel exciton many-body effects, with
the composite nature of these particles treated exactly through a procedure
similar to the one we have recently developed for Wannier excitons.


title: Melting of Branched RNA Molecules

abstract:
  Stability of the branching structure of an RNA molecule is an important
condition for its function. In this letter we show that the melting
thermodynamics of RNA molecules is very sensitive to their branching geometry
for the case of a molecule whose groundstate has the branching geometry of a
Cayley Tree and whose pairing interactions are described by the Go model.
Whereas RNA molecules with a linear geometry melt via a conventional continuous
phase transition with classical exponents, molecules with a Cayley Tree
geometry are found to have a free energy that seems smooth, at least within our
precision. Yet, we show analytically that this free energy in fact has a
mathematical singularity at the stability limit of the ordered structure. The
correlation length appears to diverge on the high-temperature side of this
singularity.


title: Steady-state MreB helices inside bacteria: dynamics without motors

abstract:
  Within individual bacteria, we combine force-dependent polymerization
dynamics of individual MreB protofilaments with an elastic model of
protofilament bundles buckled into helical configurations. We use variational
techniques and stochastic simulations to relate the pitch of the MreB helix,
the total abundance of MreB, and the number of protofilaments. By comparing our
simulations with mean-field calculations, we find that stochastic fluctuations
are significant. We examine the quasi-static evolution of the helical pitch
with cell growth, as well as timescales of helix turnover and denovo
establishment. We find that while the body of a polarized MreB helix treadmills
towards its slow-growing end, the fast-growing tips of laterally associated
protofilaments move towards the opposite fast-growing end of the MreB helix.
This offers a possible mechanism for targeted polar localization without
cytoplasmic motor proteins.


title: The supremum of conformally covariant eigenvalues in a conformal class

abstract:
  Let (M,g) be a compact Riemannian manifold of dimension >2. We show that
there is a metric h conformal to g and of volume 1 such that the first positive
eigenvalue the conformal Laplacian with repect to h is arbitrarily large. A
similar statement is proven for the first positive eigenvalue of the Dirac
operator on a spin manifold of dimension >1.


title: Vacuum driven accelerated expansion

abstract:
  It has been shown that an improved estimation of quantum vacuum energy can
yield not only acceptable but also experimentally sensible results. The very
idea consists in a straightforward extraction of gravitationally interacting
part of the full quantum vacuum energy by means of gauge transformations. The
implementation of the idea has been performed in the formalism of effective
action, in the language of Schwinger's proper time and the Seeley-DeWitt heat
kernel expansion, in the background of the Friedmann-Robertson-Walker geometry.


title:
Discrete sums of classical symbols on Z^d and zeta functions associated
  with Laplacians on tori

abstract:
  We prove the uniqueness of a translation invariant extension to non integer
order classical symbols of the ordinary discrete sum on $L^1$-symbols, which we
then describe using an Hadamard finite part procedure for sums over integer
points of infinite unions of nested convex polytopes in $\R^d$. This canonical
regularised sum is the building block to construct meromorphic extensions of
the ordinary sum on holomorphic symbols. Explicit formulae for the complex
residues at their poles are given in terms of noncommutative residues of
classical symbols, thus extending results of Guillemin, Sternberg and Weitsman.
These formulae are then applied to zeta functions associated with quadratic
forms and with Laplacians on tori.


title: G-linear sets and torsion points in definably compact groups

abstract:
  Let G be a definably compact group in an o-minimal expansion of a real closed
field. We prove that if dim(G X) < dim G for some definable X subset of G then
X contains a torsion point of G. Along the way we develop a general theory for
so-called G-linear sets, and investigate definable sets which contain abstract
subgroups of G.


title: A census of metals and baryons in stars in the local Universe

abstract:
  We combine stellar metallicity and stellar mass estimates for a large sample
of galaxies drawn from the SDSS DR2 spanning wide ranges in physical
properties, in order to derive an inventory of the total mass of metals and
baryons locked up in stars today. Physical parameter estimates are derived from
galaxy spectra with high S/N (>20). Coadded spectra of galaxies with similar
velocity dispersions, absolute r-band magnitudes and 4000\AA-break values are
used for those regions of parameter space where individual spectra have lower
S/N. We estimate the total density of metals and of baryons in stars and, from
these two quantities, we obtain a mass- and volume-averaged stellar metallicity
of <Z_star>=1.04+-0.14 Z_sun, i.e. consistent with solar. We also study how
metals are distributed in galaxies according to their mass, morphology and age,
and we then compare these distributions with the corresponding distributions of
stellar mass. We find that the bulk of metals locked up in stars in the local
Universe reside in massive, bulge-dominated galaxies, with red colours and high
4000\AA-break values corresponding to old stellar populations. Bulge-dominated
and disc-dominated galaxies contribute similar amounts to the total stellar
mass density, but have different fractional contributions to the mass density
of metals in stars, in agreement with the mass-metallicity relation.
Bulge-dominated galaxies contain roughly 40% of the total amount of metals in
stars, while disc-dominated galaxies less than 25%. Finally, at a given galaxy
stellar mass, we define two characteristic ages as the median of the
distributions of mass and metals as a function of age. These characteristic
ages decrease progressively from high-mass to low-mass galaxies, consistent
with the high formation epochs of stars in massive galaxies.


title:
Precise determination of orbital parameters in system with slowly
  drifting phases: application to the case of XTE J1807-294

abstract:
  We describe a timing technique that allows to obtain precise orbital
parameters of an accreting millisecond pulsar in those cases in which intrinsic
variations of the phase delays (caused e.g. by proper variation of the spin
frequency) with characteristic timescale longer than the orbital period do not
allow to fit the orbital parameters over a long observation (tens of days). We
show under which conditions this method can be applied and show the results
obtained applying this method to the 2003 outburst observed by RXTE of the
accreting millisecond pulsar XTE J1807-294 which shows in its phase delays a
non-negligible erratic behavior. We refined the orbital parameters of XTE
J1807-294 using all the 90 days in which the pulsation is strongly detected and
the method applicable. In this way we obtain the orbital parameters of the
source with a precision more than one order of magnitude better than the
previous available orbital solution, a precision obtained to date, on accreting
millisecond pulsars, only for XTE J1807-294 analyzing several outbursts
spanning over seven years and with a much better statistics.


title: X-ray emission from Clusters of Galaxies

abstract:
  In the last eight years, the Chandra and XMM-Newton satellites changed
significantly our view of X-ray clusters of galaxies. In particular, several
complex phenomena have been directly observed: interactions between cluster
galaxies and the Intra Cluster Medium (ICM), cold fronts in the ICM, hot
bubbles due to relativistic jets from radio loud AGN, the lack of cold gas in
``cool-cores'', and non-thermal X-ray emission. Still, this increasing
complexity does not prevent us from using X-ray clusters as a tool to constrain
cosmological parameters. In addition, observations of clusters up to redshift
~1.3 allowed us to trace the thermodynamical and chemical evolution of the ICM
on a time interval as large as 8 Gyr. In this presentation, I will give a
personal introduction to the most debated topics in this field, to end with
some prospects for the next-generation X-ray satellites.


title: Stable marked point processes

abstract:
  In many contexts such as queuing theory, spatial statistics, geostatistics
and meteorology, data are observed at irregular spatial positions. One model of
this situation involves considering the observation points as generated by a
Poisson process. Under this assumption, we study the limit behavior of the
partial sums of the marked point process $\{(t_i,X(t_i))\}$, where X(t) is a
stationary random field and the points t_i are generated from an independent
Poisson random measure $\mathbb{N}$ on $\mathbb{R}^d$. We define the sample
mean and sample variance statistics and determine their joint asymptotic
behavior in a heavy-tailed setting, thus extending some finite variance results
of Karr [Adv. in Appl. Probab. 18 (1986) 406--422]. New results on subsampling
in the context of a marked point process are also presented, with the
application of forming a confidence interval for the unknown mean under an
unknown degree of heavy tails.


title:
Lower bounds for Hilbert-Kunz multiplicities in local rings of fixed
  dimension

abstract:
  Let $(R,\m)$ be a formally unmixed local ring of positive prime
characteristic and dimension $d$. We examine the implications of having small
Hilbert-Kunz multiplicity (i.e., close to 1). In particular, we show that if
$R$ is not regular, there exists a lower bound, strictly greater than one,
depending only on $d$, for its Hilbert-Kunz multiplicity.


title: An invariant for flat virtual knots

abstract:
  The paper has been withdrawn by the author, due to a critical error stemming
from the defined template.


title:
Transmission in double quantum dots in the Kondo regime:
  Quantum-critical transitions and interference effects

abstract:
  We study the transmission through a double quantum-dot system in the Kondo
regime. An exact expression for the transmission coefficient in terms of fully
interacting many-body Green's functions is obtained. By mapping the system into
an effective Anderson impurity model, one can determine the transmission using
numerical renormalization-group methods. The transmission exhibits signatures
of the different Kondo regimes of the effective model, including an unusual
Kondo phase with split peaks in the spectral function, as well as a
pseudogapped regime exhibiting a quantum critical transition between Kondo and
unscreened phases.


title:
Equilibrium Low Temperature Heat Capacity of the Spin Density Wave
  compound (TMTTF)2 Br: effect of a Magnetic Field

abstract:
  We have investigated the effect of the magnetic field (B) on the very
low-temperature equilibrium heat capacity ceq of the quasi-1 D organic compound
(TMTTF)2Br, characterized by a commensurate Spin Density Wave (SDW) ground
state. Below 1K, ceq is dominated by a Schottky-like contribution, very
sensitive to the experimental time scale, a property that we have previously
measured in numerous DW compounds. Under applied field (in the range 0.2- 7 T),
the equilibrium dynamics, and hence ceq extracted from the time constant,
increases enormously. For B = 2-3 T, ceq varies like B2, in agreement with a
magnetic Zeeman coupling. Another specific property, common to other
Charge/Spin density wave (DW) compounds, is the occurrence of metastable
branches in ceq, induced at very low temperature by the field exceeding a
critical value. These effects are discussed within a generalization to SDWs in
a magnetic field of the available Larkin-Ovchinnikov local model of strong
pinning. A limitation of the model when compared to experiments is pointed out.


title: Unstable surface waves in running water

abstract:
  We consider the stability of periodic gravity free-surface water waves
traveling downstream at a constant speed over a shear flow of finite depth. In
case the free surface is flat, a sharp criterion of linear instability is
established for a general class of shear flows with inflection points and the
maximal unstable wave number is found. Comparison to the rigid-wall setting
testifies that free surface has a destabilizing effect. For a class of unstable
shear flows, the bifurcation of nontrivial periodic traveling waves of
small-amplitude is demonstrated at any wave number. We show the linear
instability of small nontrivial waves bifurcated at an unstable wave number of
the background shear flow. The proof uses a new formulation of the linearized
water-wave problem and a perturbation argument. An example of the background
shear flow of unstable small-amplitude periodic traveling waves is constructed
for an arbitrary vorticity strength and for an arbitrary depth, illustrating
that vorticity has a subtle influence on the stability of water waves.


title: Hellman-Feynman operator sampling in Diffusion Monte Carlo calculations

abstract:
  Diffusion Monte Carlo (DMC) calculations typically yield highly accurate
results in solid-state and quantum-chemical calculations. However, operators
that do not commute with the Hamiltonian are at best sampled correctly up to
second order in the error of the underlying trial wavefunction, once simple
corrections have been applied. This error is of the same order as that for the
energy in variational calculations. Operators that suffer from these problems
include potential energies and the density. This paper presents a new method,
based on the Hellman-Feynman theorem, for the correct DMC sampling of all
operators diagonal in real space. Our method is easy to implement in any
standard DMC code.


title: Spin polaron theory for the photoemission spectra of layered cobaltates

abstract:
  Recently, strong reduction of the quasiparticle peaks and pronounced
incoherent structures have been observed in the photoemission spectra of
layered cobaltates. Surprisingly, these many-body effects are found to increase
near the band insulator regime. We explain these unexpected observations in
terms of a novel spin-polaron model for CoO_2 planes which is based on a fact
of the spin-state quasidegeneracy of Co^{3+} ions in oxides. Scattering of the
photoholes on spin-state fluctuations suppresses their coherent motion. The
observed ``peak-dip-hump'' type lineshapes are well reproduced by the theory.


title: Perpetual American options within CTRW's

abstract:
  Continuous-time random walks are a well suited tool for the description of
market behaviour at the smallest scale: the tick-to-tick evolution. We will
apply this kind of market model to the valuation of perpetual American options:
derivatives with no maturity that can be exercised at any time. Our approach
leads to option prices that fulfil financial formulas when canonical
assumptions on the dynamics governing the process are made, but it is still
suitable for more exotic market conditions.


title: Critical conductance of a one-dimensional doped Mott insulator

abstract:
  We consider the two-terminal conductance of a one-dimensional Mott insulator
undergoing the commensurate-incommensurate quantum phase transition to a
conducting state. We treat the leads as Luttinger liquids. At a specific value
of compressibility of the leads, corresponding to the Luther-Emery point, the
conductance can be described in terms of the free propagation of
non-interacting fermions with charge e/\sqrt{2}. At that point, the temperature
dependence of the conductance across the quantum phase transition is described
by a Fermi function. The deviation from the Luther-Emery point in the leads
changes the temperature dependence qualitatively. In the metallic state, the
low-temperature conductance is determined by the properties of the leads, and
is described by the conventional Luttinger liquid theory. In the insulating
state, conductance occurs via activation of e/\sqrt{2} charges, and is
independent of the Luttinger liquid compressibility.


title:
The Laplacian on hyperbolic 3-manifolds with Dehn surgery type
  singularities

abstract:
  We study the spectrum of the Laplacian on hyperbolic 3-manifolds with Dehn
surgery type singularities and its dependence on the generalized Dehn surgery
coefficients.


title: Complex Faraday's Tensor for the Born-Infeld Theory

abstract:
  In this letter, we reconsider the Born-Infeld approach by replacing the
Faraday field-strength tensor by a complex one in the lagrangian density. We
show that an extension of the least action principle to complex-valued
lagrangian densities permits us to understand why experiments have never
exhibited nonlinear Born-Infeld effects.