title:
Estimating exposure response functions using ambient pollution
  concentrations

abstract:
  This paper presents an approach to estimating the health effects of an
environmental hazard. The approach is general in nature, but is applied here to
the case of air pollution. It uses a computer model involving ambient pollution
and temperature inputs, to simulate the exposures experienced by individuals in
an urban area, whilst incorporating the mechanisms that determine exposures.
The output from the model comprises a set of daily exposures for a sample of
individuals from the population of interest. These daily exposures are
approximated by parametric distributions, so that the predictive exposure
distribution of a randomly selected individual can be generated. These
distributions are then incorporated into a hierarchical Bayesian framework
(with inference using Markov Chain Monte Carlo simulation) in order to examine
the relationship between short-term changes in exposures and health outcomes,
whilst making allowance for long-term trends, seasonality, the effect of
potential confounders and the possibility of ecological bias.
  The paper applies this approach to particulate pollution (PM$_{10}$) and
respiratory mortality counts for seniors in greater London ($\geq$65 years)
during 1997. Within this substantive epidemiological study, the effects on
health of ambient concentrations and (estimated) personal exposures are
compared.


title: Bernoulli-Taylor formula in the case of Q-umbral Calculus

abstract:
  In this note we derive the Q-difference Bernoulli-Taylor formula with the
rest term of the Cauchy form by the Viskov's method. This is an extension of
technique by the use of Q-extented Kwasniewski's *-product . The main theorems
of Q-umbral calculus were given by G. Markowsky in 1968 and extented by
A.K.Kwasniewski.


title: Clustering of point vortices in a periodic box

abstract:
  The Monte Carlo simulation of $N$ point vortices with square periodic
boundary conditions is performed where $N$ is order of 100. The clustering
property is examined by computing the $L$ function familiar in the field of
spatial ecology. The case of a positive value of $L$ corresponds to the state
of clustering and the Onsager's negative temperature.


title: Optimal approach to quantum communication using dynamic programming

abstract:
  Reliable preparation of entanglement between distant systems is an
outstanding problem in quantum information science and quantum communication.
In practice, this has to be accomplished via noisy channels (such as optical
fibers) that generally result in exponential attenuation of quantum signals at
large distances. A special class of quantum error correction protocols--quantum
repeater protocols--can be used to overcome such losses. In this work, we
introduce a method for systematically optimizing existing protocols and
developing new, more efficient protocols. Our approach makes use of a dynamic
programming-based searching algorithm, the complexity of which scales only
polynomially with the communication distance, letting us efficiently determine
near-optimal solutions. We find significant improvements in both the speed and
the final state fidelity for preparing long distance entangled states.


title:
Spectral properties of massless and massive quarks coupled with massive
  boson at finite temperature

abstract:
  We study the properties of massless and massive quarks coupled with a scalar
and pseudoscalar boson at finite temperature in Yukawa models at the one-loop
order. The behavior of the spectral function and the pole structure of the
propagator are analyzed as functions of temperature $T$ and the quark mass
$m_f$. It is shown that the three-peak structure of the spectral function found
in a previous work for massless quarks is formed at temperatures comparable to
the boson mass even for finite $m_f$, but gradually ceases to exist as $m_f$
becomes larger. We identify the three poles of the quark propagator
corresponding to the collective excitations of the quark in the complex energy
plane. It is shown that the three trajectories made by the poles along with a
variation of $T$ undergo a structural rearrangement at a critical quark mass
when $m_f$ is increased. This suggests that the physics content of the
collective quark excitations is changed in a drastic way at this point. The
results are nicely accounted for with the notion of the level mixing induced by
a resonant scattering of the massive boson with quarks and holes of thermally
excited anti-quarks.


title: Note on q-extensions of Euler numbers and polynomials of higher order

abstract:
  In [14] Ozden-Simsek-Cangul constructed generating functions of higher-order
twisted $(h,q)$-extension of Euler polynomials and numbers, by using $p$-adic
q-deformed fermionic integral on $\Bbb Z_p$. By applying their generating
functions, they derived the complete sums of products of the twisted
$(h,q)$-extension of Euler polynomials and numbers, see[13, 14]. In this paper
we cosider the new $q$-extension of Euler numbers and polynomials to be
different which is treated by Ozden-Simsek-Cangul. From our $q$-Euler numbers
and polynomials we derive some interesting identities and we construct
$q$-Euler zeta functions which interpolate the new $q$-Euler numbers and
polynomials at a negative integer. Furthermore we study Barnes' type $q$-Euler
zeta functions. Finally we will derive the new formula for " sums products of
$q$-Euler numbers and polynomials" by using fermionic $p$-adic $q$-integral on
$\Bbb Z_p$.


title: Void-induced cross slip of screw dislocations in fcc copper

abstract:
  Pinning interaction between a screw dislocation and a void in fcc copper is
investigated by means of molecular dynamics simulation. A screw dislocation
bows out to undergo depinning on the original glide plane at low temperatures,
where the behavior of the depinning stress is consistent with that obtained by
a continuum model. If the temperature is higher than 300 K, the motion of a
screw dislocation is no longer restricted to a single glide plane due to cross
slip on the void surface. Several depinning mechanisms that involve multiple
glide planes are found. In particular, a depinning mechanism that produces an
intrinsic prismatic loop is found. We show that these complex depinning
mechanisms significantly increase the depinning stress.


title: Spatial nonlocal pair correlations in a repulsive 1D Bose gas

abstract:
  We analytically calculate the spatial nonlocal pair correlation function for
an interacting uniform 1D Bose gas at finite temperature and propose an
experimental method to measure nonlocal correlations. Our results span six
different physical realms, including the weakly and strongly interacting
regimes. We show explicitly that the characteristic correlation lengths are
given by one of four length scales: the thermal de Broglie wavelength, the mean
interparticle separation, the healing length, or the phase coherence length. In
all regimes, we identify the profound role of interactions and find that under
certain conditions the pair correlation may develop a global maximum at a
finite interparticle separation due to the competition between repulsive
interactions and thermal effects.


title:
Study of continuous-time quantum walks on quotient graphs via quantum
  probability theory

abstract:
  In the present paper, we study the continuous-time quantum walk on quotient
graphs. On such graphs, there is a straightforward reduction of problem to a
subspace that can be considerably smaller than the original one. Along the
lines of reductions, by using the idea of calculation of the probability
amplitudes for continuous-time quantum walk in terms of the spectral
distribution associated with the adjacency matrix of graphs [Jafarizadeh and
Salimi (Ann. Phys 322(2007))], we show the continuous-time quantum walk on
original graph $\Gamma$ induces a continuous-time quantum walk on quotient
graph $\Gamma_H$. Finally, for example we investigate continuous-time quantum
walk on some quotient Cayley graphs.


title:
A class of spherically-separable non-Hermitian PphiTphi-symmetric
  Hamiltonians

abstract:
  A family of spherical non-Hermitian potentials is studied. It is shown that
the corresponding non-Hermitian Hamiltonians admit some "new"
P$phi$T$phi$-symmetry. It is observed that whilst such P$phi$T$phi$-symmetric
Hamiltonians just copy the eigenvalues of V(r), the corresponding wavefunctions
would rather indulge some new probabilistic interpretations due to the change
in the azimuthal part.


title: Periodic cyclic homology of reductive p-adic groups

abstract:
  Let G be a reductive p-adic group, H(G) its Hecke algebra and S(G) its
Schwartz algebra. We will show that these algebras have the same periodic
cyclic homology. This might be used to provide an alternative proof of the
Baum-Connes conjecture for G, modulo torsion.
  As preparation for our main theorem we prove two results that have
independent interest. Firstly a general comparison theorem for the periodic
cyclic homology of finite type algebras and certain Fr\'echet completions
thereof. Secondly a refined form of the Langlands classification for G, which
clarifies the relation between the smooth spectrum and the tempered spectrum.


title:
Localization problem of the quasiperiodic system with the spin orbit
  interaction

abstract:
  We study one dimensional quasiperiodic system obtained from the tight-binding
model on the square lattice in a uniform magnetic field with the spin orbit
interaction. The phase diagram with respect to the Harper coupling and the
Rashba coupling are proposed from a number of numerical studies including a
multifractal analysis. There are four phases, I, II, III, and IV in this order
from weak to strong Harper coupling. In the weak coupling phase I all the wave
functions are extended, in the intermediate coupling phases II and III mobility
edges exist, and accordingly both localized and extended wave functions exist,
and in the strong Harper coupling phase IV all the wave functions are
localized. Phase I and Phase IV are related by the duality, and phases II and
III are related by the duality, as well. A localized wave function is related
to an extended wave function by the duality, and vice versa. The boundary
between phases II and III is the self-dual line on which all the wave functions
are critical. In the present model the duality does not lead to pure spectra in
contrast to the case of Harper equation.


title:
CLePAPS: Fast Pair Alignment of Protein Structures Based on
  Conformational Letters

abstract:
  Fast, efficient and reliable algorithms for pairwise alignment of protein
structures are in ever increasing demand for analyzing the rapidly growing data
of protein structures. CLePAPS is a tool developed for this purpose. It
distinguishes itself from other existing algorithms by the use of
conformational letters, which are discretized states of 3D segmental structural
states. A letter corresponds to a cluster of combinations of the three angles
formed by C_alpha pseudobonds of four contiguous residues. A substitution
matrix called CLESUM is available to measure similarity between any two such
letters. CLePAPS regards an aligned fragment pair (AFP) as an ungapped string
pair with a high sum of pairwise CLESUM scores. Using CLESUM scores as the
similarity measure, CLePAPS searches for AFPs by simple string comparison. The
transformation which best superimposes a highly similar AFP can be used to
superimpose the structure pairs under comparison. A highly scored AFP which is
consistent with several other AFPs determines an initial alignment. CLePAPS
then joins consistent AFPs guided by their similarity scores to extend the
alignment by several `zoom-in' iteration steps. A follow-up refinement produces
the final alignment. CLePAPS does not implement dynamic programming. The
utility of CLePAPS is tested on various protein structure pairs.


title: Asymptotic behavior of Tor over complete intersections and applications

abstract:
  Let $R$ be a local complete intersection and $M,N$ are $R$-modules such that
$\ell(\Tor_i^R(M,N))<\infty$ for $i\gg 0$. Imitating an approach by Avramov and
Buchweitz, we investigate the asymptotic behavior of $\ell(\Tor_i^R(M,N))$
using Eisenbud operators and show that they have well-behaved growth. We define
and study a function $\eta^R(M,N)$ which generalizes Serre's intersection
multiplicity $\chi^R(M,N)$ over regular local rings and Hochster's function
$\theta^R(M,N)$ over local hypersurfaces. We use good properties of
$\eta^R(M,N)$ to obtain various results on complexities of $\Tor$ and $\Ext$,
vanishing of $\Tor$, depth of tensor products, and dimensions of intersecting
modules over local complete intersections.


title:
Molecular formations in ultracold mixtures of interacting and
  noninteracting atomic gases

abstract:
  Atom-molecule equilibrium for molecular formation processes is discussed for
boson-fermion, fermion-fermion, and boson-boson mixtures of ultracold atomic
gases in the framework of quasichemical equilibrium theory. After presentation
of the general formulation, zero-temperature phase diagrams of the
atom-molecule equilibrium states are calculated analytically; molecular, mixed,
and dissociated phases are shown to appear for the change of the binding energy
of the molecules. The temperature dependences of the atom or molecule densities
are calculated numerically, and finite-temperature phase structures are
obtained of the atom-molecule equilibrium in the mixtures. The transition
temperatures of the atom or molecule Bose-Einstein condensations are also
evaluated from these results. Quantum-statistical deviations of the law of mass
action in atom-molecule equilibrium, which should be satisfied in mixtures of
classical Maxwell-Boltzmann gases, are calculated, and the difference in the
different types of quantum-statistical effects is clarified. Mean-field
calculations with interparticle interactions (atom-atom, atom-molecule, and
molecule-molecule) are formulated, where interaction effects are found to give
the linear density-dependent term in the effective molecular binding energies.
This method is applied to calculations of zero-temperature phase diagrams,
where new phases with coexisting local-equilibrium states are shown to appear
in the case of strongly repulsive interactions.


title:
The C-(symmetric) quadrilateral lattice, its transformations and the
  algebro-geometric construction

abstract:
  The C-quadrilateral lattice (CQL), called also the symmetric lattice,
provides geometric interpretation of the discrete CKP equation within the
quadrilateral lattice (QL) theory. We discuss affine-geometric properties of
the lattice emphasizing the role of the Gallucci theorem in the
multidimensional consistency of the CQL. Then we give the algebro-geometric
construction of the lattice. We also present the reduction of the vectorial
fundamental transformation of the QL to the CQL case. In the Appendix we show a
relation between the QL and the so called Darboux maps.


title: Geometry dependence of the charge transfer at YBa2Cu3O7-metal interfaces

abstract:
  Transport in electronic devices based on high-Tc superconductors depends
critically on the charge redistribution at interfaces, since the band structure
is modified on a local scale. Using the density functional theory approach for
relaxed YBa2Cu3O7-metal contacts, the charge transfer into the superconductor
has been studied in Appl. Phys. Lett. 90, 192502 (2007). In the present paper
we discuss the systematics inherent in the local electronic structure of the
near-contact YBa2Cu3O7 sites, in particular the dependence on the contact
geometry.


title: Hard X-ray variability of Magnetar's Tails observed with INTEGRAL

abstract:
  Magnetar's persistent emission above 10 keV was recently discovered thanks to
the imaging capabilities of the IBIS coded mask telescope on board the INTEGRAL
satellite. The only two sources that show some degree of long term variability
are SGR 1806-20 and 1RXS J170849.0-400910. We find some indications that
variability of these hard tails could be the driver of the spectral variability
measured in these sources below 10 keV. In addition we report for the first
time the detection at 2.8 sigma level of pulsations in the hard X-ray tail of
SGR 1806-20.


title: The complex relation between production and scattering amplitudes

abstract:
  The unitarity relation, Im(A)=T* A, is derived for a three-body production
amplitude, A, that consists of a complex linear combination of elements of the
two-body scattering amplitude, T. We conclude that the unitarity relation does
not impose a realness condition on the coefficients in the expansion of, A, in
terms of, T.


title:
Inhomogeneous charge ordering of a spinless fermionic system on the
  Bethe lattice

abstract:
  We show that a system of spinless Fermi particles, localized on the sites of
the Bethe lattice with coordination number z and interacting through a
repulsive nearest-neighbor interaction, exhibits a phase transition to a
charge-ordered state. The phase diagram in the n-T plane is derived. Relevant
thermodynamic quantities, such as the free energy, the specific heat, the
entropy and the compressibility are analyzed in detail.


title: Evolution of the genetic code. Emergence of stop codons

abstract:
  What could cause the emergence of non-encoding codons in the course of
evolution of the genetic code? Hypothesis of evolution of the genetic code from
GC to the AGUC-alphabet account for existence of stop codons.


title: On a random recursion related to absorption times of death Markov chains

abstract:
  Let $X_1,X_2,...$ be a sequence of random variables satisfying the
distributional recursion $X_1=0$ and $X_n= X_{n-I_n}+1$ for $n=2,3,...$, where
$I_n$ is a random variable with values in $\{1,...,n-1\}$ which is independent
of $X_2,...,X_{n-1}$. The random variable $X_n$ can be interpreted as the
absorption time of a suitable death Markov chain with state space ${\mathbb
N}:=\{1,2,...\}$ and absorbing state 1, conditioned that the chain starts in
the initial state $n$.
  This paper focuses on the asymptotics of $X_n$ as $n$ tends to infinity under
the particular but important assumption that the distribution of $I_n$
satisfies ${\mathbb P}\{I_n=k\}=p_k/(p_1+...+p_{n-1})$ for some given
probability distribution $p_k={\mathbb P}\{\xi=k\}$, $k\in{\mathbb N}$.
Depending on the tail behaviour of the distribution of $\xi$, several scalings
for $X_n$ and corresponding limiting distributions come into play, among them
stable distributions and distributions of exponential integrals of
subordinators. The methods used in this paper are mainly probabilistic. The key
tool is a coupling technique which relates the distribution of $X_n$ to a
random walk, which explains, for example, the appearance of the Mittag-Leffler
distribution in this context. The results are applied to describe the
asymptotics of the number of collisions for certain beta-coalescent processes.


title: A reversible theory of entanglement and its relation to the second law

abstract:
  We consider the manipulation of multipartite entangled states in the limit of
many copies under quantum operations that asymptotically cannot generate
entanglement. As announced in [Brandao and Plenio, Nature Physics 4, 8 (2008)],
and in stark contrast to the manipulation of entanglement under local
operations and classical communication, the entanglement shared by two or more
parties can be reversibly interconverted in this setting. The unique
entanglement measure is identified as the regularized relative entropy of
entanglement, which is shown to be equal to a regularized and smoothed version
of the logarithmic robustness of entanglement.
  Here we give a rigorous proof of this result, which is fundamentally based on
a certain recent extension of quantum Stein's Lemma proved in [Brandao and
Plenio, Commun. Math. 295, 791 (2010)], giving the best measurement strategy
for discriminating several copies of an entangled state from an arbitrary
sequence of non-entangled states, with an optimal distinguishability rate equal
to the regularized relative entropy of entanglement. We moreover analyse the
connection of our approach to axiomatic formulations of the second law of
thermodynamics.


title:
Midgap states in corrugated graphene: Ab-initio calculations and
  effective field theory

abstract:
  We investigate the electronic properties of corrugated graphene and show how
rippling-induced pseudomagnetic fields alter graphene's low-energy electronic
properties by combining first principles calculations with an effective field
theory. The formation of flat bands near the Fermi level corresponding to
pseudo-Landau levels is studied as a function of the rippling parameters.
Quenched and relaxed ripples turn out to be fundamentally different is this
respect: It is demonstrated, both numerically and analytically, that annealing
of quenched ripples can destroy the flat bands.


title: Decay of low-lying 12C resonances within a 3alpha cluster model

abstract:
  We compute energy distributions of three $\alpha$-particles emerging from the
decay of $^{12}$C resonances by means of the hyperspherical adiabatic expansion
method combined with complex scaling. The large distance continuum properties
of the wave functions are crucial and must be accurately calculated. The
substantial changes from small to large distances determine the decay
mechanisms. We illustrate by computing the energy distributions from decays of
the $1^{+}$ and $3^-$-resonances in $^{12}$C. These states are dominated by
direct and sequential decays into the three-body continuum respectively.


title:
Stability analysis of a max-min fair Rate Control Protocol (RCP) in a
  small buffer regime

abstract:
  In this note we analyse various stability properties of the max-min fair Rate
Control Protocol (RCP) operating with small buffers. We first tackle the issue
of stability for networks with arbitrary topologies. We prove that the max-min
fair RCP fluid model is globally stable in the absence of propagation delays,
and also derive a set of conditions for local stability when arbitrary
heterogeneous propagation delays are present. The network delay stability
result assumes that, at equilibrium, there is only one bottleneck link along
each route. Lastly, in the simpler setting of a single link, single delay
model, we investigate the impact of the loss of local stability via a Hopf
bifurcation.


title:
A new search strategy for microquasar candidates using NVSS/2MASS and
  XMM-Newton data

abstract:
  Microquasars are ideal natural laboratories for understanding
accretion/ejection processes, studying the physics of relativistic jets, and
testing gravitational phenomena. Nevertheless, these objects are difficult to
find in our Galaxy. The main goal of this work is to increase the number of
known systems of this kind. We have developed an improved search strategy based
on positional cross-identification with very restrictive selection criteria to
find new MQs, taking advantage of more sensitive modern radio and X-ray data.
We find 86 sources with positional coincidence in the NVSS/XMM catalogs at
|b|<10 deg. Among them, 24 are well-known objects and the remaining 62 sources
are unidentified. For the fully coincident sources, whenever possible, we
analyzed color-color and hardness ratio diagrams and found that at least 3 of
them display high-mass X-ray binary characteristics, making them potential
microquasar candidates.


title: Semiclassical Description of Exotic Nuclear Shapes

abstract:
  Exotic nuclear structures such as bubbles and tori are analyzed through
semiclassical extended Thomas-Fermi calculations with the Skyrme force SkM$^*$.
The variational equations for neutron and proton densities are solved fully
self-consistently in spherical (bubbles) and cylindrical (tori) symmetries. The
possible existence of bubble configurations in some astrophysical scenarios is
discussed. The stability of toroidal structures against change of quadrupole
moment is studied. A global minimum of the energy is found in heavy


title:
Right-handed sneutrinos as self-interacting dark matter in
  supersymmetric economical 3-3-1 model

abstract:
  In this work we show that the supersymmetric economical SU(3)_C X SU(3)_L X
U(1)_X (3-3-1) gauge model has a realistic candidate for self-interacting dark
matter. In the model under consideration, the right-handed sneutrino is in
bottom of the triplet, which is a singlet of the Standard Model SU(2)_L group.
In addition, the right-handed sneutrino is the lightest slepton. By these
properties, the right-handed sneutrino is weakly interacting with the Standard
Model and stable without introduction of extra symmetry. From the
Spergel-Steinhardt condition, the typical mass limit $\leq 10 $ MeV is derived.
With self-interacting coupling constant fixed by supersymmetry, this limit is
deduced without any approximation. The condition for thermal generated
self-interacting dark matter in the Universe is also obtained.


title:
Rheology of dilute polymer solutions with time-dependent screening of
  hydrodynamic interactions

abstract:
  The screening of hydrodynamic interactions (HI) essentially affects
macroscopic properties of polymeric solutions. This screening depends not only
on the polymer concentration but has a dynamic nature. In the present work, a
bead-spring theory is developed, in which this phenomenon is described for
solutions of nonentangled polymer coils. The equation of motion for the beads
of a test polymer is solved together with the Brinkman's equation for the
solvent velocity that takes into account the presence of other coils in
solution. The time correlation functions for the polymer normal modes are
found. A tendency to the screening of HI is demonstrated on the coil diffusion
as well as on the relaxation of its internal modes. With the growing
concentration of the coils they both show a transition to the exact Rouse
behavior. The viscosity of the solution and some other observable quantities
are calculated. As the time increaes, the time-dependent quantities change
their behavior from the Rouse regime through the Zimm one again to the Rouse
dynamics at long times.


title: On finite index subgroups of a universal group

abstract:
  The orbifold group of the Borromean rings with singular angle 90 degrees,
$U$, is a universal group, because every closed oriented 3--manifold $M^{3}$
occurs as a quotient space $M^{3} = H^{3}/G$, where $G$ is a finite index
subgroup of $U$. Therefore, an interesting, but quite difficult problem, is to
classify the finite index subgroups of the universal group $U$. One of the
purposes of this paper is to begin this classification. In particular we
analyze the classification of the finite index subgroups of $U$ that are
generated by rotations.


title: Tidal synchronization of the subdwarf B binary PG 0101+039

abstract:
  Tidally locked rotation is a frequently applied assumption that helps to
measure masses of invisible compact companions in close binaries. The
calculations of synchronization times are affected by large uncertainties in
particular for stars with radiative envelopes calling for observational
constraints. We aim at verifying tidally locked rotation for the binary PG
0101+039, a subdwarf B star + white dwarf binary from its tiny (0.025 %) light
variations measured with the MOST satellite (Randall et al. 2005). Binary
parameters were derived from the mass function, apparent rotation and surface
gravity of PG 0101+039 assuming a canonical mass of 0.47 Mo and tidally locked
rotation. The light curve was then synthesised and was found to match the
observed amplitude well. We verified that the light variations are due to
ellipsoidal deformation and that tidal synchronization is established for PG
0101+039. We conclude that this assumption should hold for all sdB binaries
with orbital periods of less than half a day. Hence the masses can be derived
from systems too faint to measure tiny light variations.


title:
On estimating covariances between many assets with histories of highly
  variable length

abstract:
  Quantitative portfolio allocation requires the accurate and tractable
estimation of covariances between a large number of assets, whose histories can
greatly vary in length. Such data are said to follow a monotone missingness
pattern, under which the likelihood has a convenient factorization. Upon
further assuming that asset returns are multivariate normally distributed, with
histories at least as long as the total asset count, maximum likelihood (ML)
estimates are easily obtained by performing repeated ordinary least squares
(OLS) regressions, one for each asset. Things get more interesting when there
are more assets than historical returns. OLS becomes unstable due to
rank--deficient design matrices, which is called a "big p small n" problem. We
explore remedies that involve making a change of basis, as in principal
components or partial least squares regression, or by applying shrinkage
methods like ridge regression or the lasso. This enables the estimation of
covariances between large sets of assets with histories of essentially
arbitrary length, and offers improvements in accuracy and interpretation. We
further extend the method by showing how external factors can be incorporated.
This allows for the adaptive use of factors without the restrictive assumptions
common in factor models. Our methods are demonstrated on randomly generated
data, and then benchmarked by the performance of balanced portfolios using real
historical financial returns. An accompanying R package called monomvn,
containing code implementing the estimators described herein, has been made
freely available on CRAN.


title:
2-level fractional factorial designs which are the union of non trivial
  regular designs

abstract:
  Every fraction is a union of points, which are trivial regular fractions. To
characterize non trivial decomposition, we derive a condition for the inclusion
of a regular fraction as follows. Let $F = \sum_\alpha b_\alpha X^\alpha$ be
the indicator polynomial of a generic fraction, see Fontana et al, JSPI 2000,
149-172. Regular fractions are characterized by $R = \frac 1l \sum_{\alpha \in
\mathcal L} e_\alpha X^\alpha$, where $\alpha \mapsto e_\alpha$ is an group
homeomorphism from $\mathcal L \subset \mathbb Z_2^d$ into $\{-1,+1\}$. The
regular $R$ is a subset of the fraction $F$ if $FR = R$, which in turn is
equivalent to $\sum_t F(t)R(t) = \sum_t R(t)$. If $\mathcal H = \{\alpha_1 >...
\alpha_k\}$ is a generating set of $\mathcal L$, and $R = \frac1{2^k}(1 +
e_1X^{\alpha_1}) ... (1 + e_kX^{\alpha_k})$, $e_j = \pm 1$, $j=1 ... k$, the
inclusion condition in term of the $b_\alpha$'s is % \begin{equation}b_0 + e_1
b_{\alpha_1} + >... + e_1 ... e_k b_{\alpha_1 + ... + \alpha_k} = 1.
\tag{*}\end{equation} % The last part of the paper will discuss some examples
to investigate the practical applicability of the previous condition (*).
  This paper is an offspring of the Alcotra 158 EU research contract on the
planning of sequential designs for sample surveys in tourism statistics.


title:
Algebras of unbounded operators over the ring of measurable functions
  and their derivations and automorphisms

abstract:
  In the present paper derivations and *-automorphisms of algebras of unbounded
operators over the ring of measurable functions are investigated and it is
shown that all L^0-linear derivations and L^{0}-linear *-automorphisms are
inner. Moreover, it is proved that each L^0-linear automorphism of the algebra
of all linear operators on a bo-dense submodule of a Kaplansky-Hilbert module
over the ring of measurable functions is spatial.


title:
Comment on "Pinched Flow Fractionation: Continuous Size Separation of
  Particles Utilizing a Laminar Flow Profile in a Pinched Microchannel"

abstract:
  [First paragraph] In a recent paper Yamada et al. propose the novel concept
of "pinched flow fractionation" (PFF) for the continuous size separation and
analysis of particles in microfabricated lab-on-a-chip devices. In their
description of the basic principle they claim that especially the width of the
pinched and broadened segments will affect theseparation performance. In the
following we comment on the physics behind this statement.


title: Nuclear and particle physics aspects of the 2nbb-decay of 150Nd

abstract:
  A discussion is given on possible realization of the Single State Dominance
(SSD) hypothesis in the case of the two-neutrino double beta decay(2nbb-decay)
of 150Nd with 1^- ground state of the intermediate nucleus. We conclude that
the SSD hypothesis is expected to be ruled out by precision measurement of
differential characteristics of this process in running NEMO 3 or planed
SuperNEMO experiments unlike some unknown low-lying 1^+ state of 150Pm does
exist. This problem can be solved via (d,2He) charge-exchange experiment on
150Sm. Further, we address the question about possible violation of the Pauli
exclusion principle for neutrinos and its consequences for the energy
distributions of the 2nbb-decay of 150Nd. This phenomenon might be a subject of
interest of NEMO 3 and SuperNEMO experiments as well.


title: Fermionic systems with charge correlations on the Bethe lattice

abstract:
  A fermionic model, built up of q species of localized Fermi particles,
interacting by charge correlations, is isomorphic to a spin-q/2 Ising model.
However, the equivalence is only formal and the two systems exhibit a different
physical behavior. By considering a Bethe lattice with q=1, we have exactly
solved the models. There exists a critical temperature below which there is a
spontaneous breakdown of the particle-hole symmetry for the first model, and of
the spin symmetry for the second. While the spin system is always stable and
exhibits a homogeneous ferromagnetic phase below T_{c}, the fermionic system
for T<T_{c} is unstable against the formation of inhomogeneous phases with
charge separation.


title:
Renormalization of concurrence: the application of quantum
  renormalization group to the quantum information systems

abstract:
  We have combined the idea of renormalization group and quantum information
theory. We have shown how the entanglement or concurrence evolve as the size of
the system being large, i.e. the finite size scaling is obtained. Moreover, It
introduces how the renormalization group approach can be implemented to obtain
the quantum information properties of a many body system. We have obtained the
concurrence as a measure of entanglement, its derivatives and their scaling
behavior versus the size of system for the one dimensional Ising model in
transverse field. We have found that the derivative of concurrence between two
blocks each containing half of the system size diverges at the critical point
with the exponent which is directly associated with the divergence of the
correlation length.


title: Lessons from (2+1)-dimensional quantum gravity

abstract:
  Proposals that quantum gravity gives rise to non-commutative spacetime
geometry and deformations of Poincare symmetry are examined in the context of
(2+1)-dimensional quantum gravity. The results are expressed in five lessons,
which summarise how the gravitational constant, Planck's constant and the
cosmological constant enter the non-commutative and non-cocommutative
structures arising in (2+1)-dimensional quantum gravity. It is emphasised that
the much studied bicrossproduct kappa-Poincare algebra does not arise directly
in (2+1)-dimensional quantum gravity.


title: Sturm numbers and substitution invariance of 3iet words

abstract:
  In this paper, we give a necessary condition for an infinite word defined by
a non-degenerate interval exchange on three intervals (3iet word) to be
invariant by a substitution: a natural parameter associated to this word must
be a Sturm number. We deduce some algebraic consequences from this condition
concerning the incidence matrix of the associated substitution. As a by-product
of our proof, we give a combinatorial characterization of 3iet words.


title: Relations between GPDs and TMDs: model results and beyond

abstract:
  Comparing the respective structures of the correlators defining generalized
and transverse momentum dependent parton distributions, one finds possible
relations between these two objects. Although it looks like the relations found
do not hold in general, we show that they can be established at least in simple
spectator model calculations. In addition, we discuss these relations in the
context of generalized transverse momentum dependent parton distributions.


title: Deformed Reissner--Nordstrom solutions in noncommutative gravity

abstract:
  The leading order corrections to Reissner--Nordstrom solutions of the
Einstein's equations on noncommutative space time have been worked out basing
on a noncommutative gauge theory of gravity. From the corrcted metric the
horizons have been derived and the curvature scalar is also computed. The
introduction of noncommutativity leads to the removal of the coordinate
singularities.


title: Ising model fog drip: the first two droplets

abstract:
  We present here a simple model describing coexistence of solid and vapour
phases. The two phases are separated by an interface. We show that when the
concentration of supersaturated vapour reaches the dew-point, the droplet of
solid is created spontaneously on the interface, adding to it a monolayer of a
visible size.


title: Status of the EDELWEISS-2 Dark Matter Search

abstract:
  The Edelweiss programme is dedicated to the direct search for Dark Matter as
massive weakly interacting particles (WIMPs) with Germanium cryogenic detectors
operated in the Laboratoire Souterrain de Modane in the French Alps at a depth
of 4800 mwe. After the initial phase Edelweiss I, which involved a total mass
of 1 kg, the second step of the programme, Edelweiss II, currently operates 9
kg of detectors and an active shielding of 100 m^2 muon veto detectors and is
now in its commissioning phase. The current status and performance of the
Edelweiss II set-up in terms of backgrounds will be given, the underground muon
flux measured with the muon veto system will be presented.


title:
25-nm diamond crystals hosting single NV color centers sorted by
  photon-correlation near-field microscopy

abstract:
  Diamond nanocrystals containing highly photoluminescent color centers are
attractive non-classical and near-field light sources. For near-field
applications the size of the nanocrystal is crucial since it defines the
optical resolution. NV (Nitrogen-Vacancy) color centers are efficiently created
by proton irradiation and annealing of a nanodiamond powder. Using near-field
microscopy and photon statistics measurements, we show that nanodiamond with
size down to 25 nm can hold a single NV color center with bright and stable
photoluminescence.


title:
Realization of efficient electroabsorption using intersubband
  transitions in step quantum wells

abstract:
  We have demonstrated efficient intersubband electroabsorption in
InGaAs/InAlGaAs/InAlAs step quantum wells grown by metal-organic vapor phase
epitaxy (MOVPE). An absorption modulation of 6 dB at $\lambda=6.0 \mu$m due to
Stark shift of the IS absorption was achieved at a low voltage swing of $\pm
0.5$ V in a multipass waveguide structure. Based on the experimental results it
is estimated that an electroabsorption modulator with a low peak-to-peak
voltage of $V_{pp}=0.9$ V can yield a modulation speed of $f_{3dB} \approx 120$
GHz with the present material by using a strongly confining surface plasmon
waveguide of 30 $\mu$m length.


title: Anderson localization in quantum chaos: scaling and universality

abstract:
  The one parameter scaling theory is a powerful tool to investigate Anderson
localization effects in disordered systems. In this paper we show this theory
can be adapted to the context of quantum chaos provided that the classical
phase space is homogeneous, not mixed. The localization problem in this case is
defined in momentum, not in real space. We then employ the one parameter
scaling theory to: a) propose a precise characterization of the type of
classical dynamics related to the Wigner-Dyson and Poisson statistics which
also predicts in what situations Anderson localization corrections invalidate
the relation between classical chaos and random matrix theory encoded in the
Bohigas-Schmit-Giannoni conjecture, b) to identify the universality class
associated with the metal-insulator transition in quantum chaos. In low
dimensions it is characterized by classical superdiffusion, in higher
dimensions it has in general a quantum origin as in the case of disordered
systems. We illustrate these two cases by studying 1$d$ kicked rotors with non
analytical potentials and a 3$d$ kicked rotor with a smooth potential.


title:
Geometric approach towards stable homotopy groups of spheres. Kervaire
  Invariant

abstract:
  It is proved that there exists an integer $L$ such that a framed manifold of
dimension $2^l-2$, $l\le L$ has the trivial Kervaire Invariant.


title: Lingering random walks in random environment on a strip

abstract:
  We consider a recurrent random walk (RW) in random environment (RE) on a
strip. We prove that if the RE is i. i. d. and its distribution is not
supported by an algebraic subsurface in the space of parameters defining the RE
then the RW exhibits the "(log t)-squared" asymptotic behaviour. The
exceptional algebraic subsurface is described by an explicit system of
algebraic equations.
  One-dimensional walks with bounded jumps in a RE are treated as a particular
case of the strip model. If the one dimensional RE is i. i. d., then our
approach leads to a complete and constructive classification of possible types
of asymptotic behaviour of recurrent random walks. Namely, the RW exhibits the
$(\log t)^{2}$ asymptotic behaviour if the distribution of the RE is not
supported by a hyperplane in the space of parameters which shall be explicitly
described. And if the support of the RE belongs to this hyperplane then the
corresponding RW is a martingale and its asymptotic behaviour is governed by
the Central Limit Theorem.


title: Role of t-channel meson exchange in S-wave pi N and K N scattering

abstract:
  The low-energy S-wave pi N and K N scatterings are studied by the K-matrix
approach within the meson exchange framework. The t-channel meson exchanges,
especially rho and sigma exchanges, are found to play a very important role in
these two processes. The t-channel rho exchange determines the isospin
structure of the scattering amplitudes, it gives attractive force in the low
isospin state but repulsive force in the high isospin state. The t-channel
sigma exchange gives a very large contribution in these two processes, while it
is negligible in meson-meson S-wave scatterings.


title: On reality property of Wronski maps

abstract:
  We prove that if all roots of the discrete Wronskian with step 1 of a set of
quasi-exponentials with real bases are real, simple and differ by at least 1,
then the complex span of this set of quasi-exponentials has a basis consisting
of quasi-exponentials with real coefficients. This result generalizes the B.
and M.Shapiro conjecture about spaces of polynomials.
  The proof is based on the Bethe ansatz method for the XXX model.


title: Baryogenesis -- 40 Years Later

abstract:
  The classical picture of GUT baryogenesis has been strongly modified by
theoretical progress concerning two nonperturbative features of the standard
model: the phase diagram of the electroweak theory, and baryon and lepton
number changing sphaleron processes in the high-temperature symmetric phase of
the standard model. We briefly review three viable models, electroweak
baryogenesis, the Affleck-Dine mechanism and leptogenesis and discuss the
prospects to falsify them. All models are closely tied to the nature of dark
matter, especially in supersymmetric theories. In the near future results from
LHC and gamma-ray astronomy will shed new light on the origin of the
matter-antimatter asymmetry of the universe.


title: The geometric phases in a background with Lorentz-symmetry violation

abstract:
  We analyze the nonrelativistic quantum dynamics of a single neutral spin half
particle, with non-zero magnetic and electric dipole moments, moving in an
external electromagnetic field in presence of Lorentz symmetry violation
background. Also, we study the geometric phase for this model taking into
account the parameter that breaks the Lorentz symmetry. We investigate the
He-McKellar-Wilkens effect in this context and we verify that Lorentz violation
parameter contribute to increase the electric dipole moment of the particle.


title: Non-commutative geometry and exactly solvable systems

abstract:
  I present the exact energy eigenstates and eigenvalues of a quantum many-body
system of bosons on non-commutative space and in a harmonic oszillator
confining potential at the selfdual point. I also argue that this exactly
solvable system is a prototype model which provides a generalization of mean
field theory taking into account non-trivial correlations which are peculiar to
boson systems in two space dimensions and relevant in condensed matter physics.
The prologue and epilogue contain a few remarks to relate my main story to
recent developments in non-commutative quantum field theory and an addendum to
our previous work together with Szabo and Zarembo on this latter subject.


title:
Frobenius Manifolds as a Special Class of Submanifolds in
  Pseudo-Euclidean Spaces

abstract:
  We introduce a class of potential submanifolds in pseudo-Euclidean spaces
(each N-dimensional potential submanifold is a special flat torsionless
submanifold in a 2N-dimensional pseudo-Euclidean space) and prove that each
N-dimensional Frobenius manifold can be locally represented as an N-dimensional
potential submanifold. We show that all potential submanifolds bear natural
special structures of Frobenius algebras on their tangent spaces. These special
Frobenius structures are generated by the corresponding flat first fundamental
form and the set of the second fundamental forms of the submanifolds (in fact,
the structural constants are given by the set of the Weingarten operators of
the submanifolds). We prove that the associativity equations of two-dimensional
topological quantum field theories are very natural reductions of the
fundamental nonlinear equations of the theory of submanifolds in
pseudo-Euclidean spaces and define locally the class of potential submanifolds.
The problem of explicit realization of an arbitrary concrete Frobenius manifold
as a potential submanifold in a pseudo-Euclidean space is reduced to solving a
linear system of second-order partial differential equations. For concrete
Frobenius manifolds, this realization problem can be solved explicitly in
elementary and special functions.

categories: math.DG hep-th math-ph math.AG math.AP math.MP math.SG nlin.SI


title:
Synergy of exchange bias with superconductivity in
  ferromagnetic-superconducting layered hybrids: the influence of in-plane and
  out-of-plane magnetic order on superconductivity

abstract:
  It is generally believed that superconductivity and magnetism are two
antagonistic long-range phenomena. However, as it was preliminarily highlighted
in D. Stamopoulos et al. [Phys. Rev. B 75, 014501 (2007)] and extensively
studied in this work under specific circumstances these phenomena instead of
being detrimental to each other may even become cooperative so that their
synergy may promote the superconducting properties of a hybrid structure.
  Here, we have studied systematically the magnetic and transport behavior of
such exchange biased hybrids that are comprised of ferromagnetic (FM) Ni80Fe20
and low-Tc superconducting (SC) Nb for the case where the magnetic field is
applied parallel to the specimens. Two structures have been studied: FM-SC-FM
trilayers (TLs) and FM-SC bilayers (BLs). Detailed magnetization data on the
longitudinal and transverse magnetic components are presented for both the
normal and superconducting states. These data are compared to systematic
transport measurements including I-V characteristics. The comparison of the
exchange biased BLs and TLs that are studied here with the plain ones studied
in D. Stamopoulos et al. [Phys. Rev. B 75, 184504 (2007)] enable us to reveal
an underlying parameter that may falsify the interpretation of the transport
properties of relevant FM-SC-FM TLs and FM-SC BLs investigated in the recent
literature: the underlying mechanism motivating the extreme magnetoresistance
peaks in the TLs relates to the suppression of superconductivity mainly due to
the magnetic coupling of the two FM layers as the out-of-plane rotation of
their magnetizations takes place across the coercive field where stray fields
emerge in their whole surface owing to the multidomain magnetic state that they
acquire.


title:
Anomalous effects due to the inertial anti-gravitational potential of
  the sun

abstract:
  It is introduced inertial anti-gravitational potential into the theory of
gravity to stop gravitational collapse at the nuclear density and thus prevent
singularities. It is considered effective gravity which includes Newtonian
potential and inertial anti-gravitational potential. It is investigated
footprints of the effective gravity in the solar system. The inertial
anti-gravitational potential of the sun allows to explain the anomalous
acceleration of Pioneer 10 and 11, the anomalous increase in the lunar
semi-major axis, the residuals of the seasonal variation of the proper angular
velocity of the earth, the anomalous increase of the Astronomical Unit, the
anomalous shift of the perihelion of mercury.


title: An elementary proof of Grothendieck's Non-vanishing Theorem

abstract:
  We give an elementary proof of Grothendieck's non-vanishing Theorem: For a
finitely generated non-zero module $M$ over a Noetherian local ring $A$ with
maximal ideal
  $\m$, the local cohomology module $H^{\dim M}_{\m}(M)$ is non-zero.


title: Redshift Dependent Lag-Luminosity Relation in 565 BASTE Gamma Ray Bursts

abstract:
  We compared redshifts $z_Y$ from Yonetoku relation and $z_{lag}$ from the
lag-luminosity relation for 565 BASTE GRBs and were surprised to find that the
correlation is very low. Assuming that the luminosity is a function of both
$z_Y$ and the intrinsic spectral lag $\tau_{lag}$, we found a new redshift
dependent lag-luminosity relation as $L=7.5\times 10^{50}{\rm
erg/s}(1+z)^{2.53}\tau_{lag}^{-0.282}$ with the correlation coefficient of 0.77
and the chance probability of $7.9\times 10^{-75}$. To check the validity of
this method, we examined the other luminosity indicator, Amati relation, using
$z_Y$ and the observed fluence and found the correlation coefficient of 0.92
and the chance probability of $5.2\times 10^{-106}$. Although the spectral lag
is computed from two channels of BATSE, our new lag-luminosity relation
suggests that a possible lag-luminosity relation in the \swift era should also
depend on redshift.


title: Fluctuation of the download network

abstract:
  The scaling behavior of fluctuation for a download network which we have
investigated a few years ago based upon Zhang's Encophysics web page has been
presented. A power law scaling, namely $\sigma \sim < f> ^ \alpha $ exists
between the dispersion $\sigma$ and average flux $<f>$ of the download rates.
The fluctuation exponent $\alpha$ is neither 1/2 nor 1 which was claimed as two
universal fluctuation classes in previous publication, instead it varies from
1/2 to 1 with the time window in which the download data were accumulated. The
crossover behavior of fluctuation exponents can be qualitatively understood by
the external driving fluctuation model for a small-size system or a network
traffic model which suggests congestion as the origin.

categories: physics.soc-ph cond-mat.stat-mech nucl-th physics.data-an


title: A first integration of some knot soliton models

abstract:
  Recently it has been shown that there exists a sector within the
Faddeev-Niemi model for which the equations of motion may be reduced to first
order equations. However, no solutions to that sector have been given. It is
not even known whether this sector contains topologically nontrivial solutions,
at all.
  Here, we show that two models with analytically known Hopf solitons, namely
the Nicole and the Aratyn-Ferreira-Zimerman models, possess sectors which can
be integrated to first order partial differential equations. The main result is
that these sectors are topologically nontrivial. In fact, all analytically
known hopfions belong to them.


title: Testing mu-e universality with Kl2 decays

abstract:
  The ratio R_K=Gamma(Ke2)/Gamma(Kmu2) provides a very powerful probe for the
weak interactions structure. This ratio of decay rates is calculated with very
high precision within the Standard Model but the corrections due to the
presence of New Physics could be as high as 3%. The data obtained by the NA48
experiment at the CERN SPS accelerator during a 56 hours special run in 2004
has been analyzed.The precision of the preliminary result for R_K is two times
better than the world average but is still insufficient to probe the existence
of physics Beyond the Standard Model. Currently the experiment is taking data
dedicated to the sub-percent precision measurement of R_K.


title: Phase Integral Approximation for coupled ODEs of the Schroedinger type

abstract:
  Four generalizations of the Phase Integral Approximation (PIA) to sets of N
ordinary differential equations of the Schroedinger type: u_j''(x) + Sum{k = 1
to N} R_{jk}(x) u_k(x) = 0, j = 1 to N, are described. The recurrence relations
for higher order corrections are given in the form valid in arbitrary order and
for the matrix R_{jk} either hermitian or non-hermitian. For hermitian and
negative definite R matrices, the Wronskian conserving PIA theory is formulated
which generalizes Fulling's current conserving theory pertinent to positive
definite R matrices. The idea of a modification of the PIA, well known for one
equation: u''(x) + R(x) u(x) = 0, is generalized to sets. A simplification of
Wronskian or current conserving theories is proposed which in each order
eliminates one integration from the formulas for higher order corrections. If
the PIA is generated by a non-degenerate eigenvalue of the R matrix, the
eliminated integration is the only one present. In that case, the simplified
theory becomes fully algorithmic and is generalized to non-hermitian R
matrices. General theory is illustrated by a few examples generated
automatically by using author's program in Mathematica, published in
arXiv:0710.5406.


title: Computing generators of free modules over orders in group algebras

abstract:
  Let E be a number field and G be a finite group. Let A be any O_E-order of
full rank in the group algebra E[G] and X be a (left) A-lattice. We give a
necessary and sufficient condition for X to be free of given rank d over A. In
the case that the Wedderburn decomposition of E[G] is explicitly computable and
each component is in fact a matrix ring over a field, this leads to an
algorithm that either gives an A-basis for X or determines that no such basis
exists.
  Let L/K be a finite Galois extension of number fields with Galois group G
such that E is a subfield of K and put d=[K:E]. The algorithm can be applied to
certain Galois modules that arise naturally in this situation. For example, one
can take X to be O_L, the ring of algebraic integers of L, and A to be the
associated order A of O_L in E[G]. The application of the algorithm to this
special situation is implemented in Magma under certain extra hypotheses when
K=E=Q.


title: Defects in nematic membranes can buckle into pseudospheres

abstract:
  A nematic membrane is a sheet with embedded orientational order, which can
occur in biological cells, liquid crystal films, manufactured materials, and
other soft matter systems. By formulating the free energy of nematic films
using tensor contractions from differential geometry, we elucidate the elastic
terms allowed by symmetry, and indicate differences from hexatic membranes. We
find that topological defects in the orientation field can cause the membrane
to buckle over a size set by the competition between surface tension and
in-plane elasticity. In the absence of bending rigidity the resulting shape is
universal, known as a parabolic pseudosphere or a revolved tractrix. Bending
costs oppose such buckling and modify the shape in a predictable manner. In
particular, the anisotropic rigidities of nematic membranes lead to different
shapes for aster and vortex defects, in principle enabling measurement of
couplings specific to nematic membranes.


title:
Hydrodynamics of transversally thermalized partons in ultra-relativistic
  heavy-ion collisions

abstract:
  The hydrodynamic description of transversally thermalized matter, possibly
formed at the early stages of ultra-relativistic heavy-ion collisions, is
developed. The formalism is based on the thermodynamically consistent approach
with all thermodynamic variables referring to two-dimensional objects, the
so-called transverse clusters, which are identified with the particles having
the same rapidity. The resulting hydrodynamic equations for a single cluster
have the form of the two-dimensional hydrodynamic equations of the perfect
fluid. Since the clusters do not perform any work in the longitudinal
direction, their energy is completely transformed and used to generate strong
radial and elliptic flows that turn out to be compatible with the experimental
data.


title: Implementing Quasi-Monte Carlo Simulations with Linear Transformations

abstract:
  Pricing exotic multi-asset path-dependent options requires extensive Monte
Carlo simulations. In the recent years the interest to the Quasi-monte Carlo
technique has been renewed and several results have been proposed in order to
improve its efficiency with the notion of effective dimension. To this aim,
Imai and Tan introduced a general variance reduction technique in order to
minimize the nominal dimension of the Monte Carlo method. Taking into account
these advantages, we investigate this approach in detail in order to make it
faster from the computational point of view. Indeed, we realize the linear
transformation decomposition relying on a fast ad hoc QR decomposition that
considerably reduces the computational burden. This setting makes the linear
transformation method even more convenient from the computational point of
view. We implement a high-dimensional (2500) Quasi-Monte Carlo simulation
combined with the linear transformation in order to price Asian basket options
with same set of parameters published by Imai and Tan. For the simulation of
the high-dimensional random sample, we use a 50-dimensional scrambled Sobol
sequence for the first 50 components, determined by the linear transformation
method, and pad the remaining ones out by the Latin Hypercube Sampling. The aim
of this numerical setting is to investigate the accuracy of the estimation by
giving a higher convergence rate only to those components selected by the
linear transformation technique. We launch our simulation experiment also using
the standard Cholesky and the principal component decomposition methods with
pseudo-random and Latin Hypercube sampling generators. Finally, we compare our
results and computational times, with those presented in Imai and Tan.


title:
Monte Carlo Studies of the GWW Phase Transition in Large-N Gauge
  Theories

abstract:
  In the study of the small ten-dimensional Schwarzschild blackhole, the
blackhole to string transition is an important problem. In hep-th/0605041, a
possible identification is made between the Gross-Witten-Wadia (GWW) type
third-order large-N phase transition in the boundary gauge theory and the
string-black hole transition in the bulk. In this paper, we exhibit the
existence of the GWW transition by Monte Carlo simulation in the zero mode
bosonic action of the finite-temperature N=4 SYM theory on S^3. Exhibiting this
transition in the truncated but highly non-trivial gauge theory implies that in
the vicinity of the critical temperature T_c, the system goes critical, and the
fluctuations give rise to universal formulas derived in hep-th/0605041 We also
discuss the issue of SO(6) R-symmetry breaking.


title: Graphical models for marked point processes based on local independence

abstract:
  A new class of graphical models capturing the dependence structure of events
that occur in time is proposed. The graphs represent so-called local
independences, meaning that the intensities of certain types of events are
independent of some (but not necessarily all) events in the past. This dynamic
concept of independence is asymmetric, similar to Granger non-causality, so
that the corresponding local independence graphs differ considerably from
classical graphical models. Hence a new notion of graph separation, called
delta-separation, is introduced and implications for the underlying model as
well as for likelihood inference are explored. Benefits regarding facilitation
of reasoning about and understanding of dynamic dependencies as well as
computational simplifications are discussed.


title: On Wess-Zumino terms of Brane-Antibrane systems

abstract:
  We calculate the disk level S-matrix element of one closed string RR field,
two open string tachyons and one gauge field in type II superstring theory. An
expansion for the S-matrix element has been found that its four leading order
terms are reproduced exactly by the symmetric trace tachyon DBI and the
Wess-Zumino actions of D-brane-anti-D-brane systems. Using this consistency, we
have also found the first higher derivative correction to the some of the WZ
terms.


title: Base loci of linear systems and the Waring problem

abstract:
  Waring problem for homogeneus forms asks for additive decomposition of a form
$f$ into powers of linear forms. A classical problem is to determine when such
a decomposition is unique. In this note I refine the work in
arXiv:math/0406288v1 and answer this question under a divisibility assumption.
To do this I translate the algebraic statement into a geometric one concerning
the base loci of linear systems of $P^n$ with assigned singularities.


title:
Hecke-Clifford algebras and spin Hecke algebras II: the rational double
  affine type

abstract:
  The notion of rational spin double affine Hecke algebras (sDaHa) and rational
double affine Hecke-Clifford algebras (DaHCa) associated to classical Weyl
groups are introduced. The basic properties of these algebras such as the PBW
basis and Dunkl operator representations are established. An algebra
isomorphism relating the rational DaHCa to the rational sDaHa is obtained. We
further develop a link between the usual rational Cherednik algebra and the
rational sDaHa by introducing a notion of rational covering double affine Hecke
algebras.


title: Adler function in the analytic approach to QCD

abstract:
  The low energy behavior of the Adler function D(Q^2) is studied by employing
recently derived integral representation for the latter. This representation
embodies the nonperturbative constraints on D(Q^2), in particular, it retains
the effects due to the nonvanishing pion mass. The Adler function is calculated
within the developed approach by making use of its perturbative approximation
as the only additional input. The obtained result agrees with the experimental
prediction for the Adler function in the entire energy range and possesses
remarkable stability with respect to the higher loop corrections.


title: Some aspects of extreme value theory under serial dependence

abstract:
  On the occasion of Laurens de Haan's 70th birthday, we discuss two aspects of
the statistical inference on the extreme value behavior of time series with a
particular emphasis on his important contributions. First, the performance of a
direct marginal tail analysis is compared with that of a model-based approach
using an analysis of residuals. Second, the importance of the extremal index as
a measure of the serial extremal dependence is discussed by the example of
solutions of a stochastic recurrence equation.


title:
2+1 flavour Domain Wall Fermion simulations by the RBC and UKQCD
  collaborations

abstract:
  We review simulations of dynamical domain wall fermions at a fixed inverse
lattice spacing of 1.73GeV and with pion masses as light as 330MeV and spatial
dimensions as large as 2.7fm performed by the RBC and UKQCD collaborations.
These results include pseudoscalar masses and decay constants and low energy
constants of the chiral effective lagrangian. We also review results for the
neutral kaon mixing amplitude $B_K$, the Kl3 form factor, pseudoscalar meson
structure, and vector meson decay constants. In the baryon sector we review
results for the spectrum, and nucleon form factors and structure functions.
Highlights of our programme include preliminary quark masses, and
determinations of $V_{us}$ from both $f_K/f_\pi$ and from Kl3, and an updated
result for $B_K$. We find significant finite volume effects in the nucleon
axial charge $g_A$ for our $m_\pi=330$ MeV ensemble on a $(2.7 {\rm fm})^3$
lattice, and highlight the importance of large physical volumes for non-trivial
nucleon physics.


title: Ultra-high-time Resolution Observations of Radio Bursts on AD Leonis

abstract:
  We report observations of a radio burst that occurred on the flare star AD
Leonis over a frequency range of 1120-1620 MHz (lambda ~18-27 cm). These
observations, made by the 305m telescope of the Arecibo Observatory, are unique
in providing the highest time resolution (1 ms) and broadest spectral coverage
(Delta nu/nu =0.36) of a stellar radio burst yet obtained. The burst was
observed on 2005 April 9. It produced a peak flux density of ~500 mJy and it
was essentially 100% right circularly polarized. The dynamic spectrum shows a
rich variety of structure: patchy emission, diffuse bands, and narrowband,
fast-drift striae. Focusing our attention on the fast-drift striae, we consider
the possible role of dispersion and find that it requires rather special
conditions in the source to be a significant factor. We suggest that the
emission may be due to the cyclotron maser instability, a mechanism known to
occur in planetary magnetospheres. We briefly explore implications of this
possibility.


title:
Stars and brown dwarfs in the sigma Orionis cluster: the Mayrit
  catalogue

abstract:
  The young sigma Orionis cluster is an indispensable basis for understanding
the formation and evolution of stars, brown dwarfs and planetary-mass objects.
Our knowledge of its stellar population is, however, incomplete. I present the
Mayrit catalogue, that comprises most of the stars and high-mass brown dwarfs
of the cluster. The basis of this work is an optical-near infrared correlation
between the 2MASS and DENIS catalogues in a circular area of radius 30 arcmin
centred on the OB-type binary sigma Ori AB. The analysis is supported on a
bibliographic search of confirmed cluster members with features of youth and on
additional X-ray, mid-infrared and astrometric data. I list 241 sigma Orionis
stars and brown dwarfs with known features of youth, 97 candidate cluster
members (40 are new) and 115 back- and foreground sources in the survey area.
The 338 cluster members and member candidates constitute the Mayrit catalogue.
This catalogue is a suitable input for studying the spatial ditribution,
multiplicity, properties and frequency of discs and the complete mass function
of sigma Orionis.


title:
Surface-induced First Order Transition in Athermal Polymer/Nanoparticle
  Blends

abstract:
  We investigate the phase behavior of athermal polymer/nanoparticle blends
near a hard substrate. We apply the density functional theory of Tripathi and
Chapman to these blends. We find a first order phase transition where the
nanoparticles expel the polymer from the surface to form a monolayer. The
transition density depends on the polymer length and the system bulk density.
The effect is due to the packing entropy of the species and configurational
entropy of the polymer. The simplicity of the system allows us to understand
the so-called ``entropic-push'' observed in experiments.


title: Neutrino Interaction Calculations from MeV to GeV Region

abstract:
  The Quasi-Elastic (QE) contribution of the nuclear inclusive electron model
developed in Nucl. Phys. A627 543 (1997) is extended to the study of
neutrino/antineutrino Charged Current (CC) and Neutral
  Current (NC) induced nuclear reactions at intermediate energies.
  Long range nuclear (RPA) correlations, Final State Interaction (FSI) and
Coulomb corrections are included within the model. RPA correlations are shown
to play a crucial role in the whole range (100--500 MeV) of studied neutrino
energies. Results for inclusive muon capture for different nuclei through the
Periodic Table are also discussed. In addition, and by means of a Monte Carlo
cascade method to account for the rescattering of the outgoing nucleon, we also
study the CC and NC inclusive one nucleon knockout reactions off nuclei.


title:
Combinatorial interpretation and positivity of Kerov's character
  polynomials

abstract:
  Kerov's polynomials give irreducible character values in term of the free
cumulants of the associated Young diagram. We prove in this article a
positivity result on their coefficients, which extends a conjecture of S.
Kerov. Our method, through decomposition of maps, gives a description of the
coefficients of the k-th Kerov's polynomials using permutations in S(k). We
also obtain explicit formulas or combinatorial interpretations for some
coefficients. In particular, we are able to compute the subdominant term for
character values on any fixed permutation (it was known for cycles).


title: A multifractal model for spatial variation in species richness

abstract:
  Models for species-area relationships up to now have focused on the mean
richness as a function of area. We present MFp1p2, a self-similar multifractal.
It explicitly models both trend and variation in richness as a function of
area, and is a generalisation of the model of scaling of mean species richness
due to Harte et al (1999). The construction is based on a cascade of bisections
of a rectangle. The two parameters of the model are p1, the proportion of
species that occur in the richer half, and p2, the proportion of species that
occur in the poorer half. Equivalent parameterisations are a = (p1 + p2)/2 and
b = p1/p2. These parameters are interpreted as follows: a gives the scaling of
mean density, b gives the scaling of spatial variability. Several properties of
MFp1p2 are derived, a generalisation is noted and some applications are
suggested.


title:
A double resonance approach to submillimeter/terahertz remote sensing at
  atmospheric pressure

abstract:
  The remote sensing of gases in complex mixtures at atmospheric pressure is a
challenging problem and much attention has been paid to it. The most
fundamental difference between this application and highly successful
astrophysical and upper atmospheric remote sensing is the line width associated
with atmospheric pressure broadening, ~ 5 GHz in all spectral regions. In this
paper, we discuss quantitatively a new approach that would use a short pulse
infrared laser to modulate the submillimeter/terahertz (SMM/THz) spectral
absorptions on the time scale of atmospheric relaxation. We show that such a
scheme has three important attributes: (1) The time resolved pump makes it
possible and efficient to separate signal from atmospheric and system clutter,
thereby gaining as much as a factor of 10^6 in sensitivity, (2) The 3-D
information matrix (infrared pump laser frequency, SMM/THz probe frequency, and
time resolved SMM/THz relaxation) can provide orders of magnitude greater
specificity than a sensor that uses only one of these three dimensions, and (3)
The congested and relatively weak spectra associated with large molecules can
actually be an asset because the usually deleterious effect of their
overlapping spectra can be used to increase signal strength.


title:
Eulerian and Lagrangian velocity statistics in weakly forced
  two-dimensional turbulence

abstract:
  We present statistics of velocity fluctuations in both the Lagrangian and
Eulerian frame for weakly driven two-dimensional turbulence. We find that
simultaneous inverse energy and enstrophy ranges present in the Lagrangian and
Eulerian Fourier spectra are not directly echoed in real-space moments of
velocity difference. The spectral ranges, however, do line up very well with
ratios of the real-space moments {\em local} exponents, indicating that though
the real-space moments are not scaling ``nicely'', the relative behavior of the
velocity difference probability distribution functions is changing over very
short ranges of length scales. Utilizing this technique we show that the ratios
of the local exponents for Eulerian moments in weak two-dimensional turbulence
behave in agreement with Kolmogorov predictions over the spectrally identified
ranges. The Lagrangian local exponent ratios, however, behave in a different
manner compared to their Eulerian counterparts, and deviate significantly from
what would be expected from Kolmogorov predictions.


title: Self-diffusion of Rod-like Viruses Through Smectic Layer

abstract:
  We report the direct visualization at the scale of single particles of mass
transport between smectic layers, also called permeation, in a suspension of
rod-like viruses. Self-diffusion takes place preferentially in the direction
normal to the smectic layers, and occurs by quasi-quantized steps of one rod
length. The diffusion rate corresponds with the rate calculated from the
diffusion in the nematic state with a lamellar periodic ordering potential that
is obtained experimentally.


title: Strange atoms, strange nuclei and kaon condensation

abstract:
  Analyses of comprehensive sets of strong-interaction data consisting of level
shifts, widths and yields in strange atoms of K mesons and Sigma hyperons are
reviewed. The introduction of density dependent optical potentials, in both
cases, improves significantly the fit to the data. A strongly attractive
antikaon-nuclear potential of order 150-200 MeV in nuclear matter is suggested
by fits to the kaonic-atom data, with interesting possible repercussions on
kaon condensation and on the evolution of strangeness in high-density stars.
The case for relatively narrow, deeply bound antikaon atomic states is made,
essentially independent of the nuclear potential depth. Dynamical models for
calculating binding energies and widths of antikaon-nuclear states are
discussed and a lower bound of approximately 50 MeV on the width is
established. For Sigma atoms, the fitted potential becomes repulsive inside the
nucleus, in agreement with recently reported (pi-,K+) spectra from KEK,
implying that Sigma hyperons generally do not bind in nuclei. This repulsion
significantly affects calculated compositions and masses of neutron stars.


title:
Integral field spectroscopy of L 449-1 -- A test case for spectral
  differential imaging with SINFONI

abstract:
  Spectral differential imaging is an increasingly used technique for
ground-based direct imaging searches for brown dwarf and planetary mass
companions to stars. The technique takes advantage of absorption features that
exist in these cool objects, but not in stars, and is normally implemented
through simultaneous narrow-band imagers in 2 to 4 adjacent channels. However,
by instead using an integral field unit, different spectral features could be
used depending on the actual spectrum, potentially leading to greater
flexibility and stronger detection limits. In this paper, we present the
results of a test of spectral differential imaging using the SINFONI integral
field unit at the VLT to study the nearby active star L449-1. No convincing
companion candidates are found. We find that the method provides a 3 sigma
contrast limit of 7.5 mag at 0.35", which is about 1.5 mag lower than for
NACO-SDI at the same telescope, using the same integration time. We discuss the
reasons for this, and the implications. In addition, we use the SINFONI data to
constrain the spectral type in the NIR for L 449-1, and find a result between
M3.0 and M4.0, in close agreement with a previous classification in the visual
range.


title:
Precise measurements of the eta and the neutral kaon meson masses with
  the KLOE detector

abstract:
  We present precise measurements of the eta and K0 masses using the processes
phi to eta gamma, eta to gamma gamma and phi to Ks Kl, Ks to pi+ pi-. The K0
mass measurement, M_K=497.583 +/- 0.005 (stat) +/- 0.020 (syst) MeV, is in
acceptable agreement with the previous measurements but is more accurate. We
find m(eta) = 547.874 +/- 0.007 (stat) +/- 0.031 (syst) MeV. Our value is the
most accurate to date and is in agreement with two recent measurements based on
eta decays, but is inconsistent, by about 10 sigma, with a measurement of
comparable precision based on eta production at threshold.


title: Codes from Zero-divisors and Units in Group Rings

abstract:
  We describe and present a new construction method for codes using encodings
from group rings. They consist primarily of two types: zero-divisor and
unit-derived codes. Previous codes from group rings focused on ideals; for
example cyclic codes are ideals in the group ring over a cyclic group. The
fresh focus is on the encodings themselves, which only under very limited
conditions result in ideals. We use the result that a group ring is isomorphic
to a certain well-defined ring of matrices, and thus every group ring element
has an associated matrix. This allows matrix algebra to be used as needed in
the study and production of codes, enabling the creation of standard generator
and check matrices. Group rings are a fruitful source of units and
zero-divisors from which new codes result. Many code properties, such as being
LDPC or self-dual, may be expressed as properties within the group ring thus
enabling the construction of codes with these properties. The methods are
general enabling the construction of codes with many types of group rings.
There is no restriction on the ring and thus codes over the integers, over
matrix rings or even over group rings themselves are possible and fruitful.


title:
A version of Fabry's theorem for power series with regularly varying
  coefficients

abstract:
  For real power series whose non-zero coefficients satisfy $|a_m|^{1/m}\to~1$
we prove a stronger version of Fabry theorem relating the frequency of sign
changes in the coefficients and analytic continuation of the sum of the power
series.


title:
Source-to-source optimizing transformations of Prolog programs based on
  abstract interpretation

abstract:
  Making a Prolog program more efficient by transforming its source code,
without changing its operational semantics, is not an obvious task. It requires
the user to have a clear understanding of how the Prolog compiler works, and in
particular, of the effects of impure features like the cut. The way a Prolog
code is written - e.g., the order of clauses, the order of literals in a
clause, the use of cuts or negations - influences its efficiency. Furthermore,
different optimization techniques may be redundant or conflicting when they are
applied together, depending on the way a procedure is called - e.g., inserting
cuts and enabling indexing. We present an optimiser, based on abstract
interpretation, that automatically performs safe code transformations of Prolog
procedures in the context of some class of input calls. The method is more
effective if procedures are annotated with additional information about modes,
types, sharing, number of solutions and the like. Thus the approach is similar
to Mercury. It applies to any Prolog program, however.


title: Supervised Machine Learning with a Novel Pointwise Density Estimator

abstract:
  This article proposes a novel density estimation based algorithm for carrying
out supervised machine learning. The proposed algorithm features O(n) time
complexity for generating a classifier, where n is the number of sampling
instances in the training dataset. This feature is highly desirable in
contemporary applications that involve large and still growing databases. In
comparison with the kernel density estimation based approaches, the
mathe-matical fundamental behind the proposed algorithm is not based on the
assump-tion that the number of training instances approaches infinite. As a
result, a classifier generated with the proposed algorithm may deliver higher
prediction accuracy than the kernel density estimation based classifier in some
cases.


title:
Direction-Dependent CMB Power Spectrum and Statistical Anisotropy from
  Noncommutative Geometry

abstract:
  Modern cosmology has now emerged as a testing ground for theories beyond the
standard model of particle physics. In this paper, we consider quantum
fluctuations of the inflaton scalar field on certain noncommutative spacetimes
and look for noncommutative corrections in the cosmic microwave background
(CMB) radiation. Inhomogeneities in the distribution of large scale structure
and anisotropies in the CMB radiation can carry traces of noncommutativity of
the early universe. We show that its power spectrum becomes direction-dependent
when spacetime is noncommutative. (The effects due to noncommutativity can be
observed experimentally in the distribution of large scale structure of matter
as well.) Furthermore, we have shown that the probability distribution
determining the temperature fluctuations is not Gaussian for our noncommutative
spacetimes.


title:
A Non-linear Dynamical Systems' Proof of Kraft-McMillan Inequality and
  its Converse

abstract:
  In this short paper, we shall provide a dynamical systems' proof of the
famous Kraft-McMillan inequality and its converse. Kraft-McMillan inequality is
a basic result in information theory which gives a necessary and sufficient
condition for the lengths of the codewords of a code to be uniquely decodable.


title: BCFT and Ribbon Graphs as tools for open/closed string dualities

abstract:
  In the framework of simplicial models, we construct and we fully characterize
a scalar boundary conformal field theory on a triangulated Riemann surface. The
results are analysed from a string theory perspective as tools to deal with
open/closed string dualities.


title: Exponential inequalities for empirical unbounded context trees

abstract:
  In this paper we obtain non-uniform exponential upper bounds for the rate of
convergence of a version of the algorithm Context, when the underlying tree is
not necessarily bounded. The algorithm Context is a well-known tool to estimate
the context tree of a Variable Length Markov Chain. As a consequence of the
exponential bounds we obtain a strong consistency result. We generalize in this
way several previous results in the field.


title: Quantum Cohomology and Crepant Resolutions: A Conjecture

abstract:
  We give an expository account of a conjecture, developed by
Coates--Corti--Iritani--Tseng and Ruan, which relates the quantum cohomology of
a Gorenstein orbifold X to the quantum cohomology of a crepant resolution Y of
X. We explore some consequences of this conjecture, showing that it implies
versions of both the Cohomological Crepant Resolution Conjecture and of the
Crepant Resolution Conjectures of Ruan and Bryan--Graber. We also give a
"quantized" version of the conjecture, which determines higher-genus
Gromov--Witten invariants of X from those of Y.


title: Converse Sturm-Hurwitz-Kellogg theorem and related results

abstract:
  The classical Sturm-Hurwitz-Kellogg theorem asserts that a function,
orthogonal to an n-dimensional Chebyshev system on a circle, has at least n+1
sign changes. We prove the converse: given an n-dimensional Chebyshev system on
a circle and a function with at least n+1 sign changes, there exists an
orientation preserving diffeomorphism of the circle that takes this function to
a function, orthogonal to the Chebyshev system. We also prove that if a
function on the real projective line has at least four sign changes then there
exists an orientation preserving diffeomorphism of the projective line that
takes this function to the Schwarzian derivative of some function. These
results extend the converse four vertex theorem of H. Gluck and B. Dahlberg: a
function on a circle with at least two local maxima and two local minima is the
curvature of a closed plane curve.


title: Leaky Quantum Graphs: A Review

abstract:
  The aim of this review is to provide an overview of a recent work concerning
``leaky'' quantum graphs described by Hamiltonians given formally by the
expression $-\Delta -\alpha \delta (x-\Gamma)$ with a singular attractive
interaction supported by a graph-like set in $\mathbb{R}^\nu,\: \nu=2,3$. We
will explain how such singular Schr\"odinger operators can be properly defined
for different codimensions of $\Gamma$. Furthermore, we are going to discuss
their properties, in particular, the way in which the geometry of $\Gamma$
influences their spectra and the scattering, strong-coupling asymptotic
behavior, and a discrete counterpart to leaky-graph Hamiltonians using point
interactions. The subject cannot be regarded as closed at present, and we will
add a list of open problems hoping that the reader will take some of them as a
challenge.

categories: math-ph cond-mat.mes-hall math.AP math.MP math.SP quant-ph


title:
Thermodynamical limit of general gl(N) spin chains II: Excited states
  and energies

abstract:
  We consider the thermodynamical limit of a gl(N) spin chain with arbitrary
representation at each site of the chain. We consider excitations (with holes
and new strings) above the vacuum and compute their corrections in 1/L to the
densities and the energy.

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


title:
The plasma picture of the fractional quantum Hall effect with internal
  SU(K) symmetries

abstract:
  We consider trial wavefunctions exhibiting SU(K) symmetry which may be
well-suited to grasp the physics of the fractional quantum Hall effect with
internal degrees of freedom. Systems of relevance may be either
spin-unpolarized states (K=2), semiconductors bilayers (K=2,4) or graphene
(K=4). We find that some introduced states are unstable, undergoing phase
separation or phase transition. This allows us to strongly reduce the set of
candidate wavefunctions eligible for a particular filling factor. The stability
criteria are obtained with the help of Laughlin's plasma analogy, which we
systematically generalize to the multicomponent SU(K) case. The validity of
these criteria are corroborated by exact-diagonalization studies, for SU(2) and
SU(4). Furthermore, we study the pair-correlation functions of the ground state
and elementary charged excitations within the multicomponent plasma picture.


title: New angles on top quark decay to a charged Higgs

abstract:
  To properly discover a charged Higgs Boson ($H^\pm$) requires its spin and
couplings to be determined. We investigate how to utilize $\ttbar$ spin
correlations to analyze the $H^\pm$ couplings in the decay $t\to bH^+\to
b\tau^+\nu_\tau$. Within the framework of a general Two-Higgs-Doublet Model, we
obtain results on the spin analyzing coefficients for this decay and study in
detail its spin phenomenology, focusing on the limits of large and small values
for $\tan\beta$. Using a Monte Carlo approach to simulate full hadron-level
events, we evaluate systematically how the $H^\pm\to\tau^\pm\nu_\tau$ decay
mode can be used for spin analysis. The most promising observables are obtained
from azimuthal angle correlations in the transverse rest frames of
$t(\bar{t})$. This method is particularly useful for determining the coupling
structure of $H^\pm$ in the large $\tan\beta$ limit, where differences from the
SM are most significant.


title: On an extension of the Blaschke-Santalo inequality

abstract:
  Let $K$ be a convex body and $K^\circ$ its polar body. Call
$\phi(K)=\frac{1}{|K||K^\circ|}\int_K\int_{K^\circ}< x,y>^2 dxdy$. It is
conjectured that $\phi(K)$ is maximum when $K$ is the euclidean ball. In
particular this statement implies the Blaschke-Santalo inequality. We verify
this conjecture when $K$ is restricted to be a $p$--ball.


title: Random repeated interaction quantum systems

abstract:
  We consider a quantum system S interacting sequentially with independent
systems E_m, m=1,2,... Before interacting, each E_m is in a possibly random
state, and each interaction is characterized by an interaction time and an
interaction operator, both possibly random. We prove that any initial state
converges to an asymptotic state almost surely in the ergodic mean, provided
the couplings satisfy a mild effectiveness condition. We analyze the
macroscopic properties of the asymptotic state and show that it satisfies a
second law of thermodynamics.
  We solve exactly a model in which S and all the E_m are spins: we find the
exact asymptotic state, in case the interaction time, the temperature, and the
excitation energies of the E_m vary randomly. We analyze a model in which S is
a spin and the E_m are thermal fermion baths and obtain the asymptotic state by
rigorous perturbation theory, for random interaction times varying slightly
around a fixed mean, and for small values of a coupling constant.


title: Tangles of superpositions and the convex-roof extension

abstract:
  We discuss aspects of the convex-roof extension of multipartite entanglement
measures, that is, $SL(2,\CC)$ invariant tangles. We highlight two key concepts
that contain valuable information about the tangle of a density matrix: the
{\em zero-polytope} is a convex set of density matrices with vanishing tangle
whereas the {\em convex characteristic curve} readily provides a non-trivial
lower bound for the convex roof and serves as a tool for constructing the
convex roof outside the zero-polytope. Both concepts are derived from the
tangle for superpositions of the eigenstates of the density matrix. We
illustrate their application by considering examples of density matrices for
two-qubit and three-qubit states of rank 2, thereby pointing out both the power
and the limitations of the concepts.


title: Neutronic Characterization of the Megapie Target

abstract:
  The MEGAPIE project is one of the key experiments towards the feasibility of
Accelerator Driven Systems. On-line operation and post-irradiation analysis
will provide the scientific community with unique data on the behavior of a
liquid spallation target under realistic irradiation conditions. A good
neutronics performance of such a target is of primary importance towards an
intense neutron source, where an extended liquid metal loop requires some
dedicated verifications related to the delayed neutron activity of the
irradiated PbBi. In this paper we report on the experimental characterization
of the MEGAPIE neutronics in terms of the prompt neutron (PN) flux inside the
target and the delayed neutron (DN) flux on the top of it. For the PN
measurements, a complex detector, made of 8 microscopic fission chambers, has
been built and installed in the central part of the target to measure the
absolute neutron flux and its spatial distribution. Moreover, integral
information on the neutron energy distribution as a function of the position
along the beam axis could be extracted, providing integral constraints on the
neutron production models implemented in transport codes such as MCNPX. For the
DN measurement, we used a standard 3He counter and we acquired data during the
start-up phase of the target irradiation in order to take sufficient statistics
at variable beam power. Experimental results obtained on the PN flux
characteristics and their comparison with MCNPX simulations are presented,
together with a preliminary analysis of the DN decay time spectrum.


title: The motivic zeta function and its smallest poles

abstract:
  Let f be a regular function on a nonsingular complex algebraic variety of
dimension d. We prove a formula for the motivic zeta function of f in terms of
an embedded resolution. This formula is over the Grothendieck ring itself, and
specializes to the formula of Denef and Loeser over a certain localization. We
also show that the space of n-jets satisfying f=0 can be partitioned into
locally closed subsets which are isomorphic to a cartesian product of some
variety with an affine space of dimension the round up of dn/2. Finally, we
look at the consequences for the poles of the motivic zeta function.


title:
The need for inertia in nonequilibrium steady states of sheared binary
  fluids

abstract:
  We study numerically phase separation in a binary fluid subject to an applied
shear flow in two dimensions, with full hydrodynamics. To do so, we introduce a
mixed finite-differencing/spectral simulation technique, with a transformation
to render trivial the implementation of Lees-Edwards sheared periodic boundary
conditions. For systems with inertia, we reproduce the nonequilibrium steady
states reported in a recent lattice Boltzmann study. The domain coarsening that
would occur in zero shear is arrested by the applied shear flow, which restores
a finite domain size set by the inverse shear rate. For inertialess systems, in
contrast, we find no evidence of nonequilibrium steady states free of finite
size effects: coarsening persists indefinitely until the typical domain size
attains the system size, as in zero shear. We present an analytical argument
that supports this observation, and that furthermore provides a possible
explanation for a hitherto puzzling property of the nonequilibrium steady
states with inertia.


title:
Connection between the high energy-scale evolution of the P- and T-odd
  $\pi N N$ coupling constant and the strong $\pi N N$ interaction

abstract:
  The large energy-scale behaviour of the parity and time-reversal violating
(PTV) pion-nucleon coupling constant is analyzed in a model combining
renormalization-group techniques and the dressing of the PTV vertex with a pion
loop. With the strong $\pi N N$ vertex as a mixture of the pseudovector and
pseudoscalar couplings, we show that depending on the admixture parameter, two
qualitatively distinct types of behaviour are obtained for the PTV coupling
constant at high energy scales: an asymptotic freedom or a fixed-point. We find
a critical value of the admixture parameter which delineates these two
scenarios. Several examples of the high-energy scale behaviour of the PTV $\pi
N N$ constant are considered, corresponding to realistic hadronic models of the
strong pion-nucleon interaction.


title:
An unknown story: Majorana and the Pauli-Weisskopf scalar
  electrodynamics

abstract:
  An account is given of an interesting but unknown theory by Majorana
regarding scalar quantum electrodynamics, elaborated several years before the
known Pauli-Weisskopf theory. Theoretical calculations and their interpretation
are given in detail, together with a general historical discussion of the main
steps towards the building of a quantum field theory for electrodynamics. A
possible peculiar application to nuclear constitution, as conceived around
1930, considered by Majorana is as well discussed.


title: Dynamic of threshold solutions for energy-critical NLS

abstract:
  We consider the radial energy-critical non-linear focusing Schr\"odinger
equation in dimension N=3,4,5. An explicit stationnary solution, W, of this
equation is known. In a previous work by C. Carlos and F. Merle, the energy
E(W) has been shown to be a threshold for the dynamical behavior of solutions
of the equation. In the present article, we study the dynamics at the critical
level E(u)=E(W) and classify the corresponding solutions. This gives in
particular a dynamical characterization of W.


title:
A description of the outer automorphism of S_6, and the invariants of
  six points in projective space

abstract:
  We use a simple description of the outer automorphism of S_6 to cleanly
describe the invariant theory of six points in P^1, P^2, and P^3.


title: Anomalous Diffusion with Absorbing Boundary

abstract:
  In a very long Gaussian polymer on time scales shorter that the maximal
relaxation time, the mean squared distance travelled by a tagged monomer grows
as ~t^{1/2}. We analyze such sub-diffusive behavior in the presence of one or
two absorbing boundaries and demonstrate the differences between this process
and the sub-diffusion described by the fractional Fokker-Planck equation. In
particular, we show that the mean absorption time of diffuser between two
absorbing boundaries is finite. Our results restrict the form of the effective
dispersion equation that may describe such sub-diffusive processes.


title:
Characterization of the long-period companions of the exoplanet host
  stars: HD196885, HD1237 and HD27442

abstract:
  We present the results of near-infrared, follow-up imaging and spectroscopic
observations at VLT, aimed at characterizing the long-period companions of the
exoplanet host stars HD196885, HD1237 and HD27442. The three companions were
previously discovered in the course of our CFHT and VLT coronographic imaging
survey dedicated to the search for faint companions of exoplanet host stars. We
used the NACO near-infrared adaptive optics instrument to obtain astrometric
follow-up observations of HD196885 A and B. The long-slit spectroscopic mode of
NACO and the integral field spectrograph SINFONI were used to carry out a
low-resolution spectral characterization of the three companions HD196885 B,
HD1237 B and HD27442 B between 1.4 and 2.5 microns. We can now confirm that the
companion HD196885 B is comoving with its primary exoplanet host star, as
previously shown for HD1237 B and HD27442 B. We find that both companions
HD196885 B and HD1237 B are low-mass stars of spectral type M1V and M4V
respectively. HD196885 AB is one of the closer (~23 AU) resolved binaries known
to host an exoplanet. This system is then ideal for carrying out a combined
radial velocity and astrometric investigation of the possible impact of the
binary companion on the planetary system formation and evolution. Finally, we
confirm via spectroscopy that HD27442 B is a white dwarf companion, the third
one to be discovered orbiting an exoplanet host star, following HD147513 and
Gliese 86. The detection of the broad Bracket gamma line of hydrogen indicates
a white dwarf atmosphere dominated by hydrogen.