title:
Single photon Mach-Zehnder interferometer for quantum networks based on
  the Single Photon Faraday Effect: principle and applications

abstract:
  Combining the recent progress in semiconductor nanostructures along with the
versatility of photonic crystals in confining and manipulating light, quantum
networks allow for the prospect of an integrated and low power quantum
technology. Within quantum networks, which consist of a system of waveguides
and nanocavities with embedded quantum dots, it has been demonstrated in theory
that many-qubit states stored in electron spins could be teleported from one
quantum dot to another via a single photon using the Single Photon Faraday
Effect. However, in addition to being able to transfer quantum information from
one location to another, quantum networks need added functionality such as (1)
controlling the flow of the quantum information and (2) performing specific
operations on qubits that can be easily integrated. In this paper, we show how
in principle a single photon Mach-Zehnder interferometer, which uses the
concept of the single photon Faraday Effect to manipulate the geometrical phase
of a single photon, can be operated both as a switch to control the flow of
quantum information inside the quantum network and as various single qubit
quantum gates to perform operations on a single photon. Our proposed
Mach-Zehnder interferometer can be fully integrated as part of a quantum
network on a chip. Given that the X gate, the Z gate, and the XZ gate are
essential for the implementation of quantum teleportation, we show explicitly
their implementation by means of our proposed single photon Mach-Zehnder
interferometer. We also show explicitly the implementation of the Hadamard gate
and the single-qubit phase gate, which are needed to complete the universal set
of quantum gates for integrated quantum computing in a quantum network.


title: How Very Massive Metal Free Stars Start Cosmological Reionization

abstract:
  (Abridged) Using ab initio cosmological Eulerian adaptive mesh refinement
radiation hydrodynamical calculations, we discuss how very massive stars start
the process of cosmological reionization. The models include non-equilibrium
primordial gas chemistry and cooling processes and accurate radiation transport
in the Case B approximation using adaptively ray traced photon packages,
retaining the time derivative in the transport equation. Supernova feedback is
modeled by thermal explosions triggered at parsec scales. All calculations
resolve the local Jeans length by at least 16 grid cells at all times and as
such cover a spatial dynamic range of ~10^6. These first sources of
reionization are highly intermittent and anisotropic and first photoionize the
small scales voids surrounding the halos they form in, rather than the dense
filaments they are embedded in. As the merging objects form larger, dwarf sized
galaxies, the escape fraction of UV radiation decreases and the HII regions
only break out on some sides of the galaxies making them even more anisotropic.
In three cases, SN blast waves induce star formation in overdense regions that
were formed earlier from ionization front instabilities. These stars form tens
of parsecs away from the center of their parent DM halo. Approximately 5
ionizing photons are needed per sustained ionization when star formation in
10^6 M_sun halos are dominant in the calculation. As the halos become larger
than ~10^7 M_sun, the ionizing photon escape fraction decreases, which in turn
increases the number of photons per ionization to 15-50, in calculations with
stellar feedback only. Supernova feedback in these more massive halos creates a
more diffuse medium, allowing the stellar radiation to escape more easily and
maintaining the ratio of 5 ionizing photons per sustained ionization.


title: On tilting modules over cluster-tilted algebras

abstract:
  In this paper, we show that the tilting modules over a cluster-tilted algebra
$A$ lift to tilting objects in the associated cluster category $\mathcal{C}_H$.
As a first application, we describe the induced exchange relation for tilting
$A$-modules arising from the exchange relation for tilting object in
$\mathcal{C}_H$. As a second application, we exhibit tilting $A$-modules having
cluster-tilted endomorphism algebras.


title: NLO evolution of color dipoles

abstract:
  The small-$x$ deep inelastic scattering in the saturation region is governed
by the non-linear evolution of Wilson-line operators. In the leading
logarithmic approximation it is given by the BK equation for the evolution of
color dipoles. In the next-to-leading order the BK equation gets contributions
from quark and gluon loops as well as from the tree gluon diagrams with
quadratic and cubic nonlinearities. We calculate the gluon contribution to
small-x evolution of Wilson lines (the quark part was obtained earlier).


title: SUSY QCD Corrections to Higgs Pair Production from Bottom Quark Fusion

abstract:
  We present a complete next-to-leading order (NLO) calculation for the total
cross section for inclusive Higgs pair production via bottom-quark fusion at
the CERN Large Hadron Collider (LHC) in the minimal supersymmetric standard
model (MSSM) and the minimal supergravity model (mSUGRA). We emphasize the
contributions of squark and gluino loops (SQCD) and the decoupling properties
of our results for heavy squark and gluino masses. The enhanced couplings of
the b quark to the Higgs bosons in supersymmetric models with large tanb yield
large NLO SQCD corrections in some regions of parameter space.


title:
Unzipping of two random heteropolymers: Ground state energy and finite
  size effects

abstract:
  We have analyzed the dependence of average ground state energy per monomer,
$e$, of the complex of two random heteropolymers with quenched sequences, on
chain length, $n$, in the ensemble of chains with uniform distribution of
primary sequences. Every chain monomer is randomly and independently chosen
with the uniform probability distribution $p=1/c$ from a set of $c$ different
types A, B, C, D, .... Monomers of the first chain could form saturating
reversible bonds with monomers of the second chain. The bonds between similar
monomer types (like A--A, B--B, C--C, etc.) have the attraction energy $u$,
while the bonds between different monomer types (like A--B, A--D, B--D, etc.)
have the attraction energy $v$. The main attention is paid to the computation
of the normalized free energy $e(n)$ for intermediate chain lengths, $n$, and
different ratios $a=\frac{v}{u}$ at sufficiently low temperatures when the
entropic contribution of the loop formation is negligible compared to direct
energetic interactions between chain monomers and the partition function of the
chains is dominated by the ground state. The performed analysis allows one to
derive the force, $f$, which is necessary to apply for unzipping of two random
heteropolymer chains of equal lengths whose ends are separated by the distance
$x$, averaged over all equally distributed primary structures at low
temperatures for fixed values $a$ and $c$.


title: Minimal Walking Technicolor

abstract:
  I report on our construction and analysis of the effective low energy
Lagrangian for the Minimal Walking Technicolor (MWT) model. The parameters of
the effective Lagrangian are constrained by imposing modified Weinberg sum
rules and by imposing a value for the S parameter estimated from the underlying
Technicolor theory. The constrained effective Lagrangian allows for an inverted
vector vs. axial-vector mass spectrum in a large part of the parameter space.


title: Local bulk operators in AdS/CFT and the fate of the BTZ singularity

abstract:
  This paper has two parts. First we review the description of local bulk
operators in Lorentzian AdS in terms of non-local operators in the boundary
CFT. We discuss how bulk locality arises in pure AdS backgrounds and how it is
modified at finite N. Next we present some new results on BTZ black holes:
local operators can be defined inside the horizon of a finite N BTZ black hole,
in a way that suggests the BTZ geometry describes an average over black hole
microstates, but with finite N effects resolving the singularity.


title: Denominators of cluster variables

abstract:
  Associated to any acyclic cluster algebra is a corresponding triangulated
category known as the cluster category. It is known that there is a one-to-one
correspondence between cluster variables in the cluster algebra and exceptional
indecomposable objects in the cluster category inducing a correspondence
between clusters and cluster-tilting objects.
  Fix a cluster-tilting object T and a corresponding initial cluster. By the
Laurent phenomenon, every cluster variable can be written as a Laurent
polynomial in the initial cluster. We give conditions on T equivalent to the
fact that the denominator in the reduced form for every cluster variable in the
cluster algebra has exponents given by the dimension vector of the
corresponding module over the endomorphism algebra of T.


title:
Highly Anisotropic Vorticity Aligned Structures in a Shear Thickening
  Attractive Colloidal System

abstract:
  Vorticity aligned cylindrical flocs of carbon black particles are coincident
with a primary shear thickening transition in steady flow and also appear as
transient structures in the flow response of gels produced by a secondary shear
thickening at high shear rates.


title:
Parametrically Shielding Electromagnetic Fields by Nonlinear
  Metamaterials

abstract:
  An analytical theory is developed for parametric interactions in metamaterial
multilayer structures with simultaneous nonlinear electronic and magnetic
responses and with near-zero refractive-index. We demonstrate theoretically
that electromagnetic fields of certain frequencies can be parametrically
shielded by a nonlinear left-handed material slab, where the permittivity and
permeability are both negative. The skin depth is tunable, and even in the
absence of material absorption, can be much less than the wavelength of the
electromagnetic field being shielded. This exotic behavior is a consequence of
the intricate nonlinear response in the left-handed materials and vanishing
optical refractive-index at the pump frequency.


title:
Stability of atoms and molecules in an ultrarelativistic
  Thomas-Fermi-Weizsaecker model

abstract:
  We consider the zero mass limit of a relativistic Thomas-Fermi-Weizsaecker
model of atoms and molecules. We find bounds for the critical nuclear charges
that ensure stability.


title: Heavy-Quark Masses from the Fermilab Method in Three-Flavor Lattice QCD

abstract:
  We report on heavy quark mass calculations using Fermilab heavy quarks.
Lattice calculations of heavy-strange meson masses are combined with one-loop
(automated) lattice perturbation theory to arrive at the quark mass. Mesons are
constructed from Fermilab heavy quarks and staggered light quarks. We use the
MILC ensembles at three lattice spacings and sea quark mass ratios of $m_{\rm
u,d} / m_{\rm s} = 0.1$ to 0.4. Preliminary results for the bottom quark are
given in the potential subtracted scheme.


title: Differential characters as stacks and prequantization

abstract:
  We generalize geometric prequantization of symplectic manifolds to
differentiable stacks. Our approach is atlas-independent and provides a
bijection between isomorphism classes of principal circle bundles (with or
without connections) and second cohomology groups of certain chain complexes.


title: Pressure effects in the triangular layered cobaltites NaxCoO2

abstract:
  We have measured transport properties as a function of temperature and
pressure up to 30GPa in the NaxCoO2 system. For the x=0.5 sample the transition
temperature at 53K increases with pressure, while paradoxically the sample
passes from an insulating to a metallic ground state. A similar transition is
observed in the x=0.31 sample under pressure. Compression on the x=0.75 sample
transforms the sample from a metallic to an insulating state. We discuss our
results in terms of interactions between band structure effects and Na+ order.


title:
D=11 massless superparticle covariant quantization, pure spinor BRST
  charge and hidden symmetries

abstract:
  We consider the covariant quantization of the D=11 massless superparticle
(M0-brane) in the spinor moving frame or twistor-like Lorentz harmonics
formulation. The action involves the set of 16 constrained 32 component
Majorana spinors, the spinor Lorentz harmonics parametrizing (as homogeneous
coordinates, modulo gauge symmetries) the celestial sphere S9. There presence
allows us to separate covariantly the first and the second class constraints of
the model. After taking into account the second class constraints by means of
Dirac brackets and after further reducing the first class constraints algebra,
the system is described in terms of a simple BRST charge associated to the d=1,
n=16 supersymmetry algebra. The study of the cohomology of this BRST operator
requires a regularization by complexifying the bosonic ghosts for the
kappa-symmetry and further reduction of the regularized cohomology problem to
the one for a simpler complex BRST charge which is essentially the pure spinor
BRST operator by Berkovits, but with a composite pure spinor. This exhibits a
possible origin of the complexity (non-hermiticity) characteristic of the
Berkovits pure spinor approach.
  The simple structure of the nontrivial cohomology of the M0-brane BRST charge
finds explanation in the properties that the superparticle action exhibits in
the so-called `covariantized light-cone' basis. The the covariant quantization
in this basis hints possible hidden symmetries of D=11 supergravity. Besides
SO(16), we discuss also some indirect arguments in favor of the possible E8
symmetry.


title: Matrix equations and trilinear commutation relations

abstract:
  In this paper we discuss a general algebraic approach to treating static
equations of matrix models with a mass-like term. In this approach the
equations of motions are considered as consequence of parafermi-like trilinear
commutation relations. In this context we consider several solutions, including
construction of noncommutative spheres. The equivalence of fuzzy spheres and
parafermions is underlined.


title: Black Hole Bound on the Number of Species and Quantum Gravity at LHC

abstract:
  In theories with a large number N of particle species, black hole physics
imposes an upper bound on the mass of the species equal to M_{Planck}/\sqrt{N}.
This bound suggests a novel solution to the hierarchy problem in which there
are N \approx 10^{32} gravitationally coupled species, for example 10^{32}
copies of the Standard Model. The black hole bound forces them to be at the
weak scale, hence providing a stable hierarchy. We present various arguments,
that in such theories the effective gravitational cutoff is reduced to
\Lambda_G \approx M_{Planck}/\sqrt{N} and a new description is needed around
this scale. In particular black-holes smaller than \Lambda_G^{-1} are already
no longer semi-classical. The nature of the completion is model dependent. One
natural possibility is that \Lambda_G is the quantum gravity scale. We provide
evidence that within this type of scenarios, contrary to the standard
intuition, micro black holes have a (slowly-fading) memory of the species of
origin. Consequently the black holes produced at LHC, will predominantly decay
into the Standard Model particles, and negligibly into the other species.


title: A Primer for Black Hole Quantum Physics

abstract:
  The mechanisms which give rise to Hawking radiation are revealed by analyzing
in detail pair production in the presence of horizons. In preparation for the
black hole problem, three preparatory problems are dwelt with at length: pair
production in an external electric field, thermalization of a uniformly
accelerated detector and accelerated mirrors. In the light of these examples,
the black hole evaporation problem is then presented.
  The leitmotif is the singular behavior of modes on the horizon which gives
rise to a steady rate of production. Special emphasis is put on how each
produced particle contributes to the mean albeit arising from a particular
vacuum fluctuation. It is the mean which drives the semiclassical back
reaction. This aspect is analyzed in more detail than heretofore and in
particular its drawbacks are emphasized. It is the semiclassical theory which
gives rise to Hawking's famous equation for the loss of mass of the black hole
due to evaporation $dM/dt \simeq -1/M^2$. Black hole thermodynamics is derived
from the evaporation process whereupon the reservoir character of the black
hole is manifest. The relation to the thermodynamics of the eternal black hole
through the Hartle--Hawking vacuum and the Killing identity are displayed.
  It is through the analysis of the fluctuations of the field configurations
which give rise to a particular Hawking photon that the dubious character of
the semiclassical theory is manifest. The present frontier of research revolves
around this problem and is principally concerned with the fact that one calls
upon energy scales that are greater than Planckian and the possibility of a non
unitary evolution as well. These last subjects are presented in qualitative
fashion only, so that this review stops at the threshold of quantum gravity.


title: Ehrhart polynomials of matroid polytopes and polymatroids

abstract:
  We investigate properties of Ehrhart polynomials for matroid polytopes,
independence matroid polytopes, and polymatroids. In the first half of the
paper we prove that for fixed rank their Ehrhart polynomials are computable in
polynomial time. The proof relies on the geometry of these polytopes as well as
a new refined analysis of the evaluation of Todd polynomials. In the second
half we discuss two conjectures about the h^*-vector and the coefficients of
Ehrhart polynomials of matroid polytopes; we provide theoretical and
computational evidence for their validity.


title:
Multiplicative bijections of semigroups of interval-valued continuous
  functions

abstract:
  We characterize all compact and Hausdorff spaces $X$ which satisfy that for
every multiplicative bijection $\phi$ on $C(X, I)$, there exist a homeomorphism
$\mu : X \to X$ and a continuous map $p: X \to (0, +\infty)$ such that $$\phi
(f) (x) = f(\mu (x))^{p(x)}$$ for every $f \in C(X,I)$ and $x \in X$. This
allows us to disprove a conjecture of Marovt (Proc. Amer. Math. Soc. {\bf 134}
(2006), 1065-1075). Some related results on other semigroups of functions are
also given.


title: Boundary Entropy Can Increase Under Bulk RG Flow

abstract:
  The boundary entropy log(g) of a critical one-dimensional quantum system (or
two-dimensional conformal field theory) is known to decrease under
renormalization group (RG) flow of the boundary theory. We study instead the
behavior of the boundary entropy as the bulk theory flows between two nearby
critical points. We use conformal perturbation theory to calculate the change
in g due to a slightly relevant bulk perturbation and find that it has no
preferred sign. The boundary entropy log(g) can therefore increase during
appropriate bulk flows. This is demonstrated explicitly in flows between
minimal models. We discuss the applications of this result to D-branes in
string theory and to impurity problems in condensed matter.


title: Notes on axiomatic Gromov--Witten theory and applications

abstract:
  This an expository article on Givental's axiomatic Gromov--Witten theory and
some of its applications.


title: Why things fall

abstract:
  In this paper we discuss Internal Relativity, a recent program to address the
problem of quantum gravity. In our approach we change the relationship between
spacetime and matter. Currently we view matter as propagating on spacetime.
Einstein's equations encode how spacetime curves due to the presence of matter
and how spacetime, in turn, tells matter how to propagate. In internal
realtivity matter and spacetime cease to exist as distinct entities, rather,
they arise simultaneously from an underlying quantum system. It is through the
emergent matter degrees of freedom that geometry is inferred. We have termed
our program Internal Relativity to stress the importance of looking at the
system from the point of view of an internal observer. We argue that special
relativity is then a natural consequence of this viewpoint. The most important
new aspect of Internal Relativity involves how gravity appears. It is not just
a new quantum theory of gravity but a new theory of gravity. We also argue that
the presence of a massive object implies curvature. In particular we show that
Newtonian gravity arises in the appropriate limit. Our argument implies that
there is no propagation without gravitation.


title: Ricci flow and quantum theory

abstract:
  We show some relations between Ricci flow and quantum theory via Fisher
information and the quantum potential.


title: Measurement based entanglement under conditions of extreme photon loss

abstract:
  The act of measuring optical emissions from two remote qubits can entangle
them. By demanding that a photon from each qubit reaches the detectors, one can
ensure than no photon was lost. But the failure rate then rises quadratically
with loss probability. In [1] this resulted in 30 successes per billion
attempts. We describe a means to exploit the low grade entanglement heralded by
the detection of a lone photon: A subsequent perfect operation is quickly
achieved by consuming this noisy resource. We require only two qubits per node,
and can tolerate both path length variation and loss asymmetry. The impact of
photon loss upon the failure rate is then linear; realistic high-loss devices
can gain orders of magnitude in performance and thus support QIP.


title:
Reduction to the Simplest - The Complexity of Minimalistic Heteropolymer
  Models

abstract:
  Simple coarse-grained hydrophobic-polar models for heteropolymers as the
lattice HP and the off-lattice AB model allow a general classification of
characteristic behaviors for hydrophobic-core based tertiary folding. The
strongly reduced computational efforts enable one to reveal systematically the
thermodynamic properties of comparatively long sequences in a wide temperature
range of conformational activity. Based on a suitable cooperativity parameter,
characteristic folding channels and free-energy landscapes, which have strong
similarities with realistic folding paths, can be analysed.


title: Studying the galactic outflow in NGC 1569

abstract:
  We present deep WIYN H-alpha imaging of the dwarf irregular starburst galaxy
NGC 1569, together with WIYN SparsePak spatially-resolved optical spectroscopy
of the galactic outflow. This leads on from our previous detailed analyses of
the state of the ISM in the central regions of this galaxy. Our deep imaging
reveals previously undetected ionized filaments in the outer halo. Through
combining these results with our spectroscopy we have been able to re-define
the spatial extent of the previously catalogued superbubbles, and derive
estimates for their expansion velocities, which we find to be in the range
50-100 km/s. The implied dynamical ages of <25 Myr are consistent with the
recent star- and cluster-formation histories of the galaxy. Detailed
decomposition of the multi-component H-alpha line has shown that within a
distinct region ~700x500 pc in size, roughly centred on the bright super star
cluster A, the profile is composed of a bright, narrow (FWHM <= 70 km/s)
feature with an underlying, broad component (FWHM ~ 150 km/s). Applying the
conclusions found in our previous work regarding the mechanism through which
the broad component is produced, we associate the faint, broad emission with
the interaction of the hot, fast-flowing winds from the young star clusters
with cool clumps of ISM material. This interaction generates turbulent mixing
layers on the surface of the clouds and the evaporation and/or ablation of
material into the outflow. Under this interpretation, the extent of the broad
component region may indicate an important transition point in the outflow,
where ordered expansion begins to dominate over turbulent motion. In this
context, we present a multi-wavelength discussion of the evolutionary state of
the outflow.


title: Adsorption Phenomena at Organic-Inorganic Interfaces

abstract:
  The qualitative solvent- and temperature-dependent conformational behavior of
a peptide in the proximity of solid substrates with different adsorption
properties is investigated by means of a simple lattice model. The resulting
pseudophase diagrams exhibit a complex structure, which can be understood by
analysing the minima of the free-energy landscape in dependence of appropriate
system parameters.


title:
Schemes for robust quantum computation with polar molecules: analysis of
  experimental feasibility

abstract:
  We analyse recently proposed physical implementations of a quantum computer
based on polar molecules. A set of general requirements for a molecular system
is presented, which would provide an optimal combination of quantum gate times,
coherence times, number of operations, high gate accuracy and experimental
feasibility. We proceed with a detailed analysis of a scheme utilizing
switchable dipole-dipole interactions between polar molecules. Switchable
dipole-dipole interaction is an efficient tool for realization of two-qubit
quantum gates, necessary to construct a universal set of gates. We consider
three possible realizations of a phase gate using specific molecules, such as
CO, NF, alkali dimers and alkaline-earth monohalides. We suggest suitable
electronic states and ransitions and investigate requirements for the pulses
driving them. Finally, we analyse possible sources of decoherence.


title: Charm Quarks and the QCD Equation of State

abstract:
  We present a study of the effect of charm quarks on the QCD equation of state
using partially-quenched p4 charm quarks on a dynamically generated 2+1 flavor
background, at zero chemical potential. We show preliminary results for the
charm quark contribution to the energy density and pressure in the high
temperature region ($T_c < T < 4 T_c$) and compare it to the free-field
calculation. The charm quark mass is determined by measuring the charmonium
spectrum.


title:
Geometrization of 3-dimensional Coxeter orbifolds and Singer's
  conjecture

abstract:
  Associated to any Coxeter system $(W,S)$, there is a labeled simplicial
complex $L$ and a contractible CW-complex $\Sigma_L$ (the Davis complex) on
which $W$ acts properly and cocompactly. $\Sigma_L$ admits a cellulation under
which the nerve of each vertex is $L$. It follows that if $L$ is a
triangulation of $\mathbb{S}^{n-1}$, then $\Sigma_L$ is a contractible
$n$-manifold. In this case, the orbit space, $K_L:=\Sigma_L/W$, is a
\emph{Coxeter orbifold}. We prove a result analogous to the JSJ-decomposition
for 3-dimensional manifolds: Every 3-dimensional Coxeter orbifold splits along
Euclidean suborbifolds into the \emph{characteristic suborbifold} and simple
(hyperbolic) pieces. It follows that every 3-dimensional Coxeter orbifold has a
decomposition into pieces which have hyperbolic, Euclidean, or the geometry of
$\mathbb{H}^2\times\mathbb{R}$. (We leave out the case of spherical Coxeter
orbifolds.) A version of Singer's conjecture in dimension 3 follows: That the
reduced $\ell^2$-homology of $\Sigma_L$ vanishes.


title:
Effect of Interactions on Molecular Fluxes and Fluctuations in the
  Transport Across Membrane Channels

abstract:
  Transport of molecules across membrane channels is investigated theoretically
using exactly solvable one-dimensional discrete-state stochastic models. An
interaction between molecules and membrane pores is modeled via a set of
binding sites with different energies. It is shown that the interaction
potential strongly influences the particle currents as well as fluctuations in
the number of translocated molecules. For small concentration gradients the
attractive sites lead to largest currents and fluctuations, while the repulsive
interactions yield the largest fluxes and dispersions for large concentration
gradients. Interaction energies that lead to maximal currents and maximal
fluctuations are the same only for locally symmetric potentials, while they
differ for the locally asymmetric potentials. The conditions for the most
optimal translocation transport with maximal current and minimal dispersion are
discussed. It is argued that in this case the interaction strength is
independent of local symmetry of the potential of mean forces. In addition, the
effect of the global asymmetry of the interaction potential is investigated,
and it is shown that it also strongly affects the particle translocation
dynamics. These phenomena can be explained by analyzing the details of the
particle entering and leaving the binding sites in the channel.


title:
The Extended Emission of Ultracompact HII Regions: An Overview and New
  Observations

abstract:
  Here we present a brief overview of UC HII regions with EE (UC HII+EE)
including our most recent effort aimed at searching for UC HII regions
associated with extended emission.


title: QWalk: A Quantum Monte Carlo Program for Electronic Structure

abstract:
  We describe QWalk, a new computational package capable of performing Quantum
Monte Carlo electronic structure calculations for molecules and solids with
many electrons. We describe the structure of the program and its implementation
of Quantum Monte Carlo methods. It is open-source, licensed under the GPL, and
available at the web site http://www.qwalk.org


title:
Using generalized PowerFlux methods to estimate the parameters of
  periodic gravitational waves

abstract:
  We investigate methods to estimate the parameters of the gravitational-wave
signal from a spinning neutron star using Fourier transformed segments of the
strain response from an interferometric detector. Estimating the parameters
from the power, we find generalizations of the PowerFlux method. Using
simulated elliptically polarized signals injected into Gaussian noise, we apply
the generalized methods to estimate the squared amplitudes of the plus and
cross polarizations (and, in the most general case, the polarization angle),
and test the relative detection efficiencies of the various methods.


title:
Search for Standard Model Higgs Bosons Produced in Association with W
  Bosons

abstract:
  We report on the results of a search for standard model Higgs bosons produced
in association with W bosons from p-pbar collisions at root s = 1.96 TeV. The
search uses a data sample corresponding to approximately 1 fb-1 of integrated
luminosity. Events consistent with the W to l-nu and H to b-bbar signature are
selected by triggering on a high-pT electron or muon candidate and tagging one
or two of the jet candidates as having originated from b quarks. A neural
network filter rejects a fraction of tagged charm and light flavor jets,
increasing the b-jet purity in the sample and thereby reducing the background
to Higgs boson production. We observe no excess l-nu-b-bbar production beyond
the background expectation, and we set 95% confidence level upper limits on the
production cross section times branching fraction sigma(p-pbar to WH) times
Br(H to b-bbar) ranging from 3.9 to 1.3 pb, for specific Higgs boson mass
hypotheses in the range 110 to 150 GeV/c2, respectively.


title: Stellar Objects of Extragalactic Origin in the Galactic Halo

abstract:
  We identified globular clusters and field stars of extragalactic origin and
investigated their chemical, physical, and kinematical properties. This objects
as supposed was captured by the Galaxy at different times from debris of the
dwarf satellite galaxies disrupted by its tidal forces. The results are
follows. (1) The majorities of metal-poor stellar objects in the Galaxy have an
extragalactic origin. (2) The masses of the accreted globular clusters decrease
with the removal from the center and the plane of the Galaxy. (3) The relative
abundances of chemical elements in the accreted and genetically connected stars
are essentially distinguished. (4) The accreted field stars demonstrate the
decrease of the relative magnesium abundanses with an increase in sizes and
inclinations of their orbits. (5) The stars of the Centaurus moving group were
born from the matter, in which star formation rate was considerably lower than
in the early Galaxy. On the base of these properties was made a conclusion that
with the decrease of the masses of the dwarf galaxies in them simultaneously
decrease the average masses of globular clusters and the maximum masses of
supernova SNe II. Namely latter fact leads to the decrease of the relative
abundances of \alpha-elements in their metal-poor stars.


title:
The Three-body Force and the Tetraquark Interpretation of Light Scalar
  Mesons

abstract:
  We study the possible tetraquark interpretation of light scalar meson states
$a_0(980)$, $f_0(980)$, $\kappa$, $\sigma$ within the framework of the
non-relativistic potential model. The wave functions of tetraquark states are
obtained in a space spanned by multiple Gaussian functions. We find that the
mass spectra of the light scalar mesons can be well accommodated in the
tetraquark picture if we introduce a three-body quark interaction in the quark
model. Using the obtained multiple Gaussian wave functions, the decay constants
of tetraquarks are also calculated within the ``fall apart'' mechanism.


title: Conformally parametrized surfaces associated with CP^(N-1) sigma models

abstract:
  Two-dimensional conformally parametrized surfaces immersed in the su(N)
algebra are investigated. The focus is on surfaces parametrized by solutions of
the equations for the CP^(N-1) sigma model. The Lie-point symmetries of the
CP^(N-1) model are computed for arbitrary N. The Weierstrass formula for
immersion is determined and an explicit formula for a moving frame on a surface
is constructed. This allows us to determine the structural equations and
geometrical properties of surfaces in R^(N^2-1). The fundamental forms,
Gaussian and mean curvatures, Willmore functional and topological charge of
surfaces are given explicitly in terms of any holomorphic solution of the CP^2
model. The approach is illustrated through several examples, including surfaces
immersed in low-dimensional su(N) algebras.


title:
A nuclear magnetic resonance spectrometer for operation around 1 MHz
  with a sub 10 mK noise temperature based on a two stage dc SQUID

abstract:
  We have developed a nuclear magnetic resonance spectrometer with a series
tuned input circuit for measurements on samples at millikelvin temperatures
based on an integrated two-stage superconducting quantum interference device
current sensor, with an energy sensitivty e = 26 +/-1 h when operated at 1.4K.
To maximise the sensitivity both the NMR pickup coil and tuning capacitor need
to be cooled, and the tank circuit parameters should be chosen to equalise the
contributions from circulating current noise and voltage noise in the SQUID. A
noise temperature TN = 7 +/-2 mK was measured, at a frequency of 0.884 MHz,
with the circuit parameters close to optimum.


title: Topological Hochschild homology of l and ko

abstract:
  We calculate the integral homotopy groups of THH(l) at any prime and of
THH(ko) at p=2, where l is the Adams summand of the connective complex p-local
K-theory spectrum and ko is the connective real K-theory spectrum.


title:
Sensitivity and parameter-estimation precision for alternate LISA
  configurations

abstract:
  We describe a simple framework to assess the LISA scientific performance
(more specifically, its sensitivity and expected parameter-estimation precision
for prescribed gravitational-wave signals) under the assumption of failure of
one or two inter-spacecraft laser measurements (links) and of one to four
intra-spacecraft laser measurements. We apply the framework to the simple case
of measuring the LISA sensitivity to monochromatic circular binaries, and the
LISA parameter-estimation precision for the gravitational-wave polarization
angle of these systems. Compared to the six-link baseline configuration, the
five-link case is characterized by a small loss in signal-to-noise ratio (SNR)
in the high-frequency section of the LISA band; the four-link case shows a
reduction by a factor of sqrt(2) at low frequencies, and by up to ~2 at high
frequencies. The uncertainty in the estimate of polarization, as computed in
the Fisher-matrix formalism, also worsens when moving from six to five, and
then to four links: this can be explained by the reduced SNR available in those
configurations (except for observations shorter than three months, where five
and six links do better than four even with the same SNR). In addition, we
prove (for generic signals) that the SNR and Fisher matrix are invariant with
respect to the choice of a basis of TDI observables; rather, they depend only
on which inter-spacecraft and intra-spacecraft measurements are available.


title: Gamma-Ray Bursts May Be Biased Tracers of Star Formation

abstract:
  Based on a simulation of galaxy formation in the standard cosmological model,
we suggest that a consistent picture for Gamma-Ray Bursts and star formation
may be found that is in broad agreement with observations: GRBs preferentially
form in low metallicity environments and in galaxies substantially less
luminous that L*. We find that the computed formation rate of stars with
metallicity less than 0.1Zsun agrees remarkably well with the rate evolution of
Gamma-Ray Bursts observed by Swift from z=0 to z=4, whereas the evolution of
total star formation rate is weaker by a factor of about 4. Given this finding,
we caution that any inference of star formation rate based on observed GRB rate
may require a more involved exercise than a simple proportionality.


title:
Optical Absorption Study by Ab initio Downfolding Approach: Application
  to GaAs

abstract:
  We examine whether essence and quantitative aspects of electronic excitation
spectra are correctly captured by an effective low-energy model constructed
from an {\em ab initio} downfolding scheme. A global electronic structure is
first calculated by {\em ab initio} density-functional calculations with the
generalized gradient approximation. With the help of constrained density
functional theory, the low-energy effective Hamiltonian for bands near the
Fermi level is constructed by the downfolding procedure in the basis of
maximally localized Wannier functions. The excited states of this low-energy
effective Hamiltonian ascribed to an extended Hubbard model are calculated by
using a low-energy solver. As the solver, we employ the Hartree-Fock
approximation supplemented by the single-excitation configuration-interaction
method considering electron-hole interactions. The present three-stage method
is applied to GaAs, where eight bands are retained in the effective model after
the downfolding. The resulting spectra well reproduce the experimental results,
indicating that our downfolding scheme offers a satisfactory framework of the
electronic structure calculation, particularly for the excitations and dynamics
as well as for the ground state.


title: Prediction Space Weather Using an Asymmetric Cone Model for Halo CMEs

abstract:
  Halo coronal mass ejections (HCMEs) are responsible of the most severe
geomagnetic storms. A prediction of their geoeffectiveness and travel time to
Earth's vicinity is crucial to forecast space weather.
  Unfortunately coronagraphic observations are subjected to projection effects
and do not provide true characteristics of CMEs. Recently, Michalek (2006, {\it
Solar Phys.}, {\bf237}, 101) developed an asymmetric cone model to obtain the
space speed, width and source location of HCMEs. We applied this technique to
obtain the parameters of all front-sided HCMEs observed by the SOHO/LASCO
experiment during a period from the beginning of 2001 until the end of 2002
(solar cycle 23). These parameters were applied for the space weather forecast.
Our study determined that the space speeds are strongly correlated with the
travel times of HCMEs within Earth's vicinity and with the magnitudes related
to geomagnetic disturbances.


title: Is Strangeness Still Strange at the LHC?

abstract:
  Strangeness production is calculated in a pQCD-based model (including nuclear
effects) in the high transverse momentum sector, where pQCD is expected to work
well. We investigate pion, kaon, proton and lambda production in pp and
heavy-ion collisions. Parton energy loss in AA collisions is taken into
account. We compare strange-to-non-strange meson and baryon ratios to data at
RHIC, and make predictions for the LHC. We find that these ratios significantly
deviate from unity not only at RHIC but also at the LHC, indicating the special
role of strangeness at both energies.


title:
The IMF of Extremely Metal-Poor Stars and the Probe into the
  Star-Formation Process of the Milky Way

abstract:
  We discuss the star formation history of the Galaxy, based on the
observations of extremely metal-poor stars (EMP) in the Galactic halo, to gain
an insight into the evolution and structure formation in the early universe.
The initialmass function (IMF) of EMP stars is derived from the observed
fraction of carbon-enhanced EXP (CEMP) stars among the EMP survivors, which are
thought to originate from the evolution in the close binary systems with mass
transfer. Relying upon the theory of the evolution of EMP stars and of their
binary evolution, we find that stars of metallicity [Fe/H]<-2.5 were formed at
typical mass of ~10M_sun. The top heavy IMF thus obtained is applied to study
the early chemical evolution of the Galaxy. We construct the merging history of
our Galaxy semi-analytically and derive the metallicity distribution function
(MDF) of low-mass EMP stars that survive to date with taking into account the
contribution of binary systems. It is shown that the resultant MDF can well
reproduce the observed distribution of EMP survivors, and, in particular, that
they almost all stem from a less-mass companion in binary systems. We also
investigate how first stars affect the MDF of EMP stars.


title:
Bergman kernels and equilibrium measures for line bundles over
  projective manifolds

abstract:
  Let L be a holomorphic line bundle over a compact complex projective
Hermitian manifold X. Any fixed smooth hermitian metric h on L induces a
Hilbert space structure on the space of global holomorphic sections with values
in the k th tensor power of L. In this paper various convergence results are
obtained for the corresponding Bergman kernels (i.e. orthogonal projection
kernels). The convergence is studied in the large k limit and is expressed in
terms of the equilibrium metric h_e associated to h, as well as in terms of the
Monge-Ampere measure of h on a certain support set. It is also shown that the
equilibrium metric h_e is in the class C^{1,1} on the complement of the
augmented base locus of L. For L ample these results give generalizations of
well-known results concerning the case when the curvature of h is globally
positive (then h_e=h). In general, the results can be seen as local metrized
versions of Fujita's approximation theorem for the volume of L.


title:
Castelnuovo-Mumford regularity and reduction number of smooth monomial
  curves

abstract:
  We compare, for smooth monomial projective curves, the Castel- nuovo-Mumford
regularity and the reduction number; we present an example where these two
numbers differ. However, we show they coin- cide for a certain class of
monomial curves. Furthermore, for smooth monomial curves we prove an inequality
which is stronger than the one from the Eisenbud-Goto conjecture.


title:
Deformation of Dijkgraaf-Vafa Relation via Spontaneously Broken N=2
  Supersymmetry II

abstract:
  We consider the matter induced part of the effective superpotential of N=2,
U(N) gauge model in which N=2 supersymmetry is spontaneously broken to N=1, by
using the properties of the chiral ring and the generalized Konishi anomaly
equations derived in our previous paper arXiv:0704.1060. It is shown that the
effective superpotential is related to the planar free energy of the matrix
model by a formula which consists of two parts -- the well-known part due to
Dijkgraaf-Vafa and the part that acts as a deformation of the couplings. These
couplings are those of the original bare prepotential in the action and at the
same time matrix model couplings.


title: On The Pomeron at Large 't Hooft Coupling

abstract:
  We begin the process of unitarizing the Pomeron at large 't Hooft coupling.
We do so first in the conformal regime, which applies to good accuracy to a
number of real and toy problems in QCD. We rewrite the conformal Pomeron in the
$J$-plane and transverse position space, and then work out the eikonal
approximation to multiple Pomeron exchange. This is done in the context of a
more general treatment of the complex $J$-plane and the geometric consequences
of conformal invariance. The methods required are direct generalizations of our
previous work on single Pomeron exchange and on multiple graviton exchange in
AdS space, and should form a starting point for other investigations. We
consider unitarity and saturation in the conformal regime, noting elastic and
absorptive effects, and exploring where different processes dominate. Our
methods extend to confining theories and we briefly consider the Pomeron kernel
in this context. Though there is important model dependence that requires
detailed consideration, the eikonal approximation indicates that the Froissart
bound is generically both satisfied and saturated.


title:
Chemical freeze-out temperature in hydrodynamical description of Au+Au
  collisions at sqrt(s_NN) = 200 GeV

abstract:
  We study the effect of separate chemical and kinetic freeze-outs to the ideal
hydrodynamical flow in Au+Au collisions at RHIC (sqrt(s_NN) = 200 GeV energy).
Unlike in earlier studies we explore how these effects can be counteracted by
changes in the initial state of the hydrodynamical evolution. We conclude that
the reproduction of pion, proton and antiproton yields necessitates a chemical
freeze-out temperature of T = 150 MeV instead of T = 160 - 170 MeV motivated by
thermal models. Unlike previously reported, this lower temperature makes it
possible to reproduce the p_T-spectra of hadrons if one assumes very small
initial time, tau_0 = 0.2 fm/c. However, the p_T-differential elliptic flow,
v_2(p_T) remains badly reproduced. This points to the need to include
dissipative effects (viscosity) or some other refinement to the model.


title: Studies of penguin dominated B decays

abstract:
  We present measurements on penguin dominated B decays which are sensitive to
new physics, such as CP-violation parameters and branching fractions in $b \to
s q\bar{q}$ and $b \to d q\bar{q}$ gluonic and radiative decays using a large
sample of $B\bar{B}$ pairs recorded at the $\Upsilon(4S)$ resonance with the
Belle detector at the KEKB asymmetric energy $e^+e^-$ collider.


title:
Solution and Asymptotic Behavior for a Nonlocal Coupled System of
  Reaction-Diffusion

abstract:
  This paper concerns with existence, uniqueness and asymptotic behavior of the
solutions for a nonlocal coupled system of reaction-diffusion. We prove the
existence and uniqueness of weak solutions by the Faedo-Galerkin method and
exponential decay of solutions by the classic energy method. We improve the
results obtained by Chipot-Lovato and Menezes for coupled systems. A numerical
scheme is presented.


title: Isotopies of Legendrian 1-knots and Legendrian 2-tori

abstract:
  We construct a Legendrian 2-torus in the 1-jet space of $S^1\times\R$ (or of
$\R^2$) from a loop of Legendrian knots in the 1-jet space of $\R$. The
differential graded algebra (DGA) for the Legendrian contact homology of the
torus is explicitly computed in terms of the DGA of the knot and the monodromy
operator of the loop. The contact homology of the torus is shown to depend only
on the chain homotopy type of the monodromy operator. The construction leads to
many new examples of Legendrian knotted tori. In particular, it allows us to
construct a Legendrian torus with DGA which does not admit any augmentation
(linearization) but which still has non-trivial homology, as well as two
Legendrian tori with isomorphic linearized contact homologies but with distinct
contact homologies.


title:
Some matrices associated with the split decomposition for a Q-polynomial
  distance-regular graph

abstract:
  We consider a $Q$-polynomial distance-regular graph $\Gamma$ with vertex set
$X$ and diameter $D \geq 3$. For $\mu, \nu \in \lbrace \downarrow, \uparrow
\rbrace$ we define a direct sum decomposition of the standard module $V=\C X$,
called the $(\mu,\nu)$--split decomposition. For this decomposition we compute
the complex conjugate and transpose of the associated primitive idempotents.
Now fix $b,\beta \in \mathbb C$ such that $b \neq 1$ and assume $\Gamma$ has
classical parameters $(D,b,\alpha,\beta)$ with $\alpha = b-1$. Under this
assumption Ito and Terwilliger displayed an action of the $q$-tetrahedron
algebra $\boxtimes_q$ on the standard module of $\Gamma$. To describe this
action they defined eight matrices in
  $\hbox{Mat}_X(\mathbb C)$, called \begin{eqnarray*} \label{eq:list} A,\quad
A^*,\quad B,\quad B^*, \quad K,\quad K^*,\quad \Phi,\quad \Psi. \end{eqnarray*}
  For each matrix in the above list we compute the transpose and complex
conjugate. Using this information we compute the transpose and complex
conjugate for each generator of $\boxtimes_q$ on $V$.


title: Dark Matter, Dark Energy and Rotation Curves

abstract:
  Models for DM are invoked with various density distributions, to account for
flat rotation curves of galaxies. The effect of DE on these profiles for large
galaxies and clusters are also studied. The rotation curves are shown to dip at
a particular distance, when the effect of DE became significant.


title:
Non-measurable automorphisms of Lie groups relative to the real- and
  non-archimedean-valued measures

abstract:
  In this work the problem about an existence of non-measurable automorphisms
of Lie groups finite and as well infinite dimensional over the field of real
numbers and also over the non-archimedean local fields is investigated.
Non-measurability of automorphisms is considered relative to real-valued
measures and also measures with values in non-archimedean local fields. Their
existence is proved and a procedure for their construction is given. Their
application for a construction of non-measurable irreducible unitary
representations is demonstrated.


title: Quantum stabilization of Z-strings, a status report on D=3+1 dimensions

abstract:
  We investigate an extension to the phase shift formalism for calculating
one-loop determinants. This extension is motivated by requirements of the
computation of Z-string quantum energies in D=3+1 dimensions. A subtlety that
seems to imply that the vacuum polarization diagram in this formalism is
(erroneously) finite is thoroughly investigated.


title: Oxygen abundance methods in the SDSS: view from modern statistics

abstract:
  Our purpose is to find which is the most reliable one among various oxygen
abundance determination methods. We will test the validity of several different
oxygen abundance determination methods using methods of modern statistics.
These methods include Bayesian analysis and information scoring. We will
analyze a sample of $\sim$6000 $\hii$ galaxies from the Sloan Digital Sky
Survey (SDSS) spectroscopic observations data release four. All methods that we
used drew the same conclusion that the $T_e$ method is a more reliable oxygen
abundance determination methods than the Bayesian metallcity method under the
existing telescope ability. The ratios of the likelihoods between the different
kinds of methods tell us that the $T_e$, $P$, and $O3N2$ methods are consistent
with each other because the $P$ and $O3N2$ method are calibrated by
$T_e$-method. The Bayesian and $R_{23}$ method are consistent with each other
because both are calibrated by a galaxy model. In either case, the $N2$ method
is an {\it unreliable} method.


title:
Resolving the wave-vector and the refractive index from the coefficient
  of reflectance

abstract:
  We resolve the existing controversy concerning the selection of the sign of
the normal-to-the-interface component of the wave-vector $k_z$ of an
electromagnetic wave in an active (gain) medium. Our method exploits the fact
that no ambiguity exists in the case of a {\em film} of the active medium since
its coefficient of reflectance is invariant under the inversion of the sign of
$k_z$. Then we show that the limit of the infinite film thickness determines a
unique and physically consistent choice of the wave-vector and the refractive
index. Practically important implications of the theory are identified and
discussed.


title: Dynamic importance sampling for queueing networks

abstract:
  Importance sampling is a technique that is commonly used to speed up Monte
Carlo simulation of rare events. However, little is known regarding the design
of efficient importance sampling algorithms in the context of queueing
networks. The standard approach, which simulates the system using an a priori
fixed change of measure suggested by large deviation analysis, has been shown
to fail in even the simplest network setting (e.g., a two-node tandem network).
Exploiting connections between importance sampling, differential games, and
classical subsolutions of the corresponding Isaacs equation, we show how to
design and analyze simple and efficient dynamic importance sampling schemes for
general classes of networks. The models used to illustrate the approach include
$d$-node tandem Jackson networks and a two-node network with feedback, and the
rare events studied are those of large queueing backlogs, including total
population overflow and the overflow of individual buffers.


title:
Chirality-Biased Point Defects Dynamics on a Disclination Line in a
  Nematic Liquid Crystal

abstract:
  Chiral additives in the nematic liquid crystal can alter the dynamics of
point defects moving on a disclination line. They exert a constant force on
defects, leading to the bimodal distribution of distances between them at long
times. The evolution of the system of defects in the presence of chiral
additives provides a very direct proof of the existence of repulsive forces
between the defects at large distances. We find that addition of a sufficient
amount of chiral compound removes all point defects from the system. The
process is studied in the system of 8CB (4-n-octyl-4 '-cyanobiphenyl) doped
with the chiral compound S811 (from Merck Co.) and in the computer simulations.


title: Scattering of sine-Gordon Breathers on Potential Wells

abstract:
  We analyse the scattering of sine-Gordon breathers on a square potential
well. We show that the scattering process depends not only on the vibration
frequency of the breather and its incoming speed but also on its phase as well
as the depth and width of the well. We show that the breather can pass through
the well and exit with a speed different, sometime larger, from the initial
one. It can also be trapped and very slowly decay inside the well or bounce out
of the well and go back to where it came from. We also show that the breather
can split into a kink and an anti-kink pair when it hits the well.


title: Kernel estimation of Greek weights by parameter randomization

abstract:
  A Greek weight associated to a parameterized random variable $Z(\lambda)$ is
a random variable $\pi$ such that
$\nabla_{\lambda}E[\phi(Z(\lambda))]=E[\phi(Z(\lambda))\pi]$ for any function
$\phi$. The importance of the set of Greek weights for the purpose of Monte
Carlo simulations has been highlighted in the recent literature. Our main
concern in this paper is to devise methods which produce the optimal weight,
which is well known to be given by the score, in a general context where the
density of $Z(\lambda)$ is not explicitly known. To do this, we randomize the
parameter $\lambda$ by introducing an a priori distribution, and we use
classical kernel estimation techniques in order to estimate the score function.
By an integration by parts argument on the limit of this first kernel
estimator, we define an alternative simpler kernel-based estimator which turns
out to be closely related to the partial gradient of the kernel-based estimator
of $\mathbb{E}[\phi(Z(\lambda))]$. Similarly to the finite differences
technique, and unlike the so-called Malliavin method, our estimators are
biased, but their implementation does not require any advanced mathematical
calculation. We provide an asymptotic analysis of the mean squared error of
these estimators, as well as their asymptotic distributions. For a
discontinuous payoff function, the kernel estimator outperforms the classical
finite differences one in terms of the asymptotic rate of convergence. This
result is confirmed by our numerical experiments.


title: Quantum reference frames and deformed symmetries

abstract:
  In the context of constrained quantum mechanics, reference systems are used
to construct relational observables that are invariant under the action of the
symmetry group. Upon measurement of a relational observable, the reference
system undergoes an unavoidable measurement "back-action" that modifies its
properties. In a quantum-gravitational setting, it has been argued that such a
back-action may produce effects that are described at an effective level as a
form of deformed (or doubly) special relativity. We examine this possibility
using a simple constrained system that has been extensively studied in the
context of quantum information. While our conclusions support the idea of a
symmetry deformation, they also reveal a host of other effects that may be
relevant to the context of quantum gravity, and could potentially conceal the
symmetry deformation.


title: Markovian perturbation, response and fluctuation dissipation theorem

abstract:
  We consider the Fluctuation Dissipation Theorem (FDT) of statistical physics
from a mathematical perspective. We formalize the concept of "linear response
function" in the general framework of Markov processes. We show that for
processes out of equilibrium it depends not only on the given Markov process
X(s) but also on the chosen perturbation of it. We characterize the set of all
possible response functions for a given Markov process and show that at
equilibrium they all satisfy the FDT. That is, if the initial measure is
invariant for the given Markov semi-group, then for any pair of times s<t and
nice functions f,g, the dissipation, that is, the derivative in s of the
covariance of g(X(t)) and f(X(s)) equals the infinitesimal response at time t
and direction g to any Markovian perturbation that alters the invariant measure
of X(.) in the direction of f at time s. The same applies in the so called FDT
regime near equilibrium, i.e. in the limit s going to infinity with t-s fixed,
provided X(s) converges in law to an invariant measure for its dynamics. We
provide the response function of two generic Markovian perturbations which we
then compare and contrast for pure jump processes on a discrete space, for
finite dimensional diffusion processes, and for stochastic spin systems.


title: The base components of the dualizing sheaf of a curve on a surface

abstract:
  This note studies the structure of the divisorial fixed part of the dualizing
sheaf of a 1-connected curve D on a smooth surface S. It is shown that if the
divisorial fixed part F of the dualizing sheaf is non empty then it has
arithmetic genus<1 and each component of F is a smooth rational curve.


title:
A general dynamical statistical model with possible causal
  interpretation

abstract:
  We develop a general dynamical model as a framework for possible causal
interpretation. We first state a criterion of local independence in terms of
measurability of processes involved in the Doob-Meyer decomposition of
stochastic processes, as in Aalen (1987); then we define direct and indirect
influence. We propose a definition of causal influence using the concepts of
``physical system''. This framework makes it possible to link descriptive and
explicative statistical models, and encompasses quantitative processes and
events. One of the features of this paper is the clear distinction between the
model for the system and the model for the observation. We give a dynamical
representation of a conventional joint model for HIV load and CD4 counts. We
show its inadequacy to capture causal influences while on the contrary known
mechanisms of HIV infection can be expressed directly through a system of
differential equations.


title: A Direct Multigrid Poisson Solver for Oct-Tree Adaptive Meshes

abstract:
  We describe a finite-volume method for solving the Poisson equation on
oct-tree adaptive meshes using direct solvers for individual mesh blocks. The
method is a modified version of the method presented by Huang and Greengard
(2000), which works with finite-difference meshes and does not allow for shared
boundaries between refined patches. Our algorithm is implemented within the
FLASH code framework and makes use of the PARAMESH library, permitting
efficient use of parallel computers. We describe the algorithm and present test
results that demonstrate its accuracy.


title:
Thermodynamics of DNA loops with long-range correlated structural
  disorder

abstract:
  We study the influence of a structural disorder on the thermodynamical
properties of 2D-elastic chains submitted to mechanical/topological constraint
as loops. The disorder is introduced via a spontaneous curvature whose
distribution along the chain presents either no correlation or long-range
correlations (LRC). The equilibrium properties of the one-loop system are
derived numerically and analytically for weak disorder. LRC are shown to favor
the formation of small loop, larger the LRC, smaller the loop size. We use the
mean first passage time formalism to show that the typical short time loop
dynamics is superdiffusive in the presence of LRC. Potential biological
implications on nucleosome positioning and dynamics in eukaryotic chromatin are
discussed.


title: Magnetic tight-binding and the iron-chromium enthalpy anomaly

abstract:
  We describe a self consistent magnetic tight-binding theory based in an
expansion of the Hohenberg-Kohn density functional to second order, about a non
spin polarised reference density. We show how a first order expansion about a
density having a trial input magnetic moment leads to the Stoner--Slater rigid
band model. We employ a simple set of tight-binding parameters that accurately
describes electronic structure and energetics, and show these to be
transferable between first row transition metals and their alloys. We make a
number of calculations of the electronic structure of dilute Cr impurities in
Fe which we compare with results using the local spin density approximation.
The rigid band model provides a powerful means for interpreting complex
magnetic configurations in alloys; using this approach we are able to advance a
simple and readily understood explanation for the observed anomaly in the
enthalpy of mixing.


title: HNC, HCN and CN in Seyfert galaxies

abstract:
  Bright HNC 1--0 emission has been found towards several Seyfert galaxies.
This is unexpected since traditionally HNC is a tracer of cold (10 K) gas, and
the molecular gas of luminous galaxies like Seyferts is thought to have bulk
kinetic temperatures surpassing 50 K. In this work we aim to distinguish the
cause of the bright HNC and to model the physical conditions of the HNC and HCN
emitting gas. We have used SEST, JCMT and IRAM 30m telescopes to observe HNC
3-2 and HCN 3-2 line emission in a selection of 5 HNC-luminous Seyfert
galaxies. We estimate and discuss the excitation conditions of HCN and HNC in
NGC 1068, NGC 3079, NGC 2623 and NGC 7469, based on the observed 3-2/1-0 line
intensity ratios. We also observed CN 1-0 and 2-1 emission and discuss its role
in photon and X-ray dominated regions. HNC 3-2 was detected in 3 galaxies (NGC
3079, NGC 1068 and NGC 2623). HCN 3-2 was detected in NGC 3079, NGC 1068 and
NGC 1365. The HCN 3-2/1-0 ratio is lower than 0.3 only in NGC 3079, whereas the
HNC 3-2/1-0 ratio is larger than 0.3 only in NGC 2623. The HCN/HNC 1-0 and 3-2
line ratios are larger than unity in all the galaxies. The HCN/HNC 3-2 line
ratio is lower than unity only in NGC 2623, similar to Arp 220, Mrk 231 and NGC
4418. In three of the galaxies the HNC emissions emerge from gas of densities
n<10^5 cm^3, where the chemistry is dominated by ion-neutral reactions. In NGC
1068 the emission of HNC emerges from lower (<10^5 cm^3) density gas than HCN
(>10^5 cm^3). Instead, the emissions of HNC and HCN emerge from the same gas in
NGC 3079. The observed HCN/HNC and CN/HCN line ratios favor a PDR scenario,
rather than an XDR one. However, the N(HNC)/N(HCN) column density ratios
obtained for NGC 3079 can be found only in XDR environments.


title: Dynamics of axialized laser-cooled ions in a Penning trap

abstract:
  We report the experimental characterization of axialization - a method of
reducing the magnetron motion of a small number of ions stored in a Penning
trap. This is an important step in the investigation of the suitability of
Penning traps for quantum information processing. The magnetron motion was
coupled to the laser-cooled modified cyclotron motion by the application of a
near-resonant oscillating quadrupole potential (the "axialization drive").
Measurement of cooling rates of the radial motions of the ions showed an
order-of-magnitude increase in the damping rate of the magnetron motion with
the axialization drive applied. The experimental results are in good
qualitative agreement with a recent theoretical study. In particular, a
classical avoided crossing was observed in the motional frequencies as the
axialization drive frequency was swept through the optimum value, proving that
axialization is indeed a resonant effect.


title:
Control of Optical Dynamic Memory Capacity of an Atomic Bose-Einstein
  Condensate

abstract:
  Light storage in an atomic Bose-Einstein condensate is one of the most
practical usage of these coherent atom-optical systems. In order to make them
even more practical, it is necessary to enhance our ability to inject multiple
pulses into the condensate. In this paper, we report that dispersion of pulses
injected into the condensate can be compensated by optical nonlinearity. In
addition, we will present a brief review of our earlier results in which
enhancement of light storage capacity is accomplished by utilizing multi-mode
light propagation or choosing an optimal set of experimental parameters.


title: Deterministic distributed dense coding with stabilizer states

abstract:
  We consider the possibility of using stabilizer states to perform
deterministic dense coding among multiple senders and a single receiver. In the
model we studied, the utilized stabilizer state is partitioned into several
subsystems and then each subsystem is held by a distinct party. We present a
sufficient condition for a stabilizer state to be useful for deterministic
distributed dense coding with respect to a given partition plan. The
corresponding protocol is also constructed. Furthermore, we propose a method to
partially solve a more general problem of finding the set of achievable
alphabet sizes for an arbitrary stabilizer state with respect to an arbitrary
partition plan. Finally, our work provides a new perspective from the
stabilizer formalism to view the standard dense coding protocol and also
unifies several previous results in a single framework.


title:
Attrition and Non-Response in Panel Data: The Case of the Canadian
  Survey of Labor and Income Dynamics

abstract:
  This paper provides an analysis of the effects of attrition and non-response
on employment and wages using the Canadian Survey of Labour and Income
Dynamics. We consider a structural model composed of three freely correlated
equations for nonattrition/response, employment and wages. The model is
estimated using microdata from 22,990 individuals who provided sufficient
information in the first wave of the 1996-2001 panel. The main findings of the
paper are that attrition is not random. Attritors and non-respondents likely
are less attached to employment and come from low-income population. The
correlation between non-attrition and employment is positive and statistically
significant, though small. Also, wage estimates are biased upwards. Observed
wages are on average higher than wages that would be observed if all the
individuals initially selected in the panel remained in the sample.


title: Chiral Low-Energy Constants: Status and Prospects

abstract:
  Chiral low-energy constants (LECs) carry the information of short-distance
dynamics involving heavier degrees of freedom not present in the chiral
Lagrangian. Our knowledge of the LECs is all-important at phenomenological
level because their relevance in the prediction of hadronic observables at
low-energies and on the other side because they provide hints on the
construction of a dual theory of QCD in the low-energy regime. I review briefly
the status of these important couplings.


title:
Rigidity and non local connectivity of Julia sets of some quadratic
  polynomials

abstract:
  For an infinitely renormalizable quadratic map $f_c: z\mapsto z^2+c$ with the
sequence of renormalization periods ${k_m}$ and rotation numbers
${t_m=p_m/q_m}, we prove that if $\limsup k_m^{-1}\log |p_m|>0$, then the
Mandelbrot set is locally connected at $c$. We prove also that if $\limsup
|t_{m+1}|^{1/q_m}<1$ and $q_m\to \infty$, then the Julia set of $f_c$ is not
locally connected and the Mandelbrot set is locally connected at $c$ provided
that all the renormalizations are non-primitive (satellite). This quantifies a
construction of A. Douady and J. Hubbard, and weakens a condition proposed by
J. Milnor.
  Abstract of the Addendum: We improve one of the main results of the above
paper.


title: Planetesimal accretion in binary star systems

abstract:
  Numerical simulations of planetesimal accretion in circumprimary and
circumbinary orbits are described. The secular perturbations by the com- panion
star and gas drag are included in our models. We derive limits on the
parameters of the binary system for which accretion and then planetary forma-
tion are possible. In the circumbinary case we also outline the radial distance
from the baricenter of the stars beyond which accumulation always occurs. Hy-
drodynamical simulations are also presented to validate our N-body approach
based on the axisymmetric approximation for the gas of the disk.


title:
Generation of two-mode field squeezing through selective dynamics in
  cavity QED

abstract:
  We propose a scheme for the generation of a two-mode field squeezed state in
cavity QED. It is based on two-channel Raman excitations of a beam of
three-level atoms with random arrival times by two classical fields and two
high-Q resonator modes. It is shown that by suitably choosing the intensities
and detunings of fields the dynamical processes can be selective and two-mode
squeezing between the cavity modes can be generated at steady state. This
proposal does not need the preparation of the initial states of atoms and
cavity modes, and is robust against atomic spontaneous decay.


title:
The sharp lower bound for the volume of 3-folds of general type with
  \chi(\Co{X})=1

abstract:
  Let $V$ be a smooth projective 3-fold of general type. Denote by $K^{3}$, a
rational number, the self-intersection of the canonical sheaf of any minimal
model of $V$. One defines $K^{3}$ as a canonical volume of $V$. The paper is
devoted to proving the sharp lower bound $K^{3}\ge {1/420}$ which can be
reached by an example: $X_{46}\subseteq \mathbb{P}(4,5,6,7,23)$.


title: A Multi-level Blocking Distinct Degree Factorization Algorithm

abstract:
  We give a new algorithm for performing the distinct-degree factorization of a
polynomial P(x) over GF(2), using a multi-level blocking strategy. The coarsest
level of blocking replaces GCD computations by multiplications, as suggested by
Pollard (1975), von zur Gathen and Shoup (1992), and others. The novelty of our
approach is that a finer level of blocking replaces multiplications by
squarings, which speeds up the computation in GF(2)[x]/P(x) of certain interval
polynomials when P(x) is sparse. As an application we give a fast algorithm to
search for all irreducible trinomials x^r + x^s + 1 of degree r over GF(2),
while producing a certificate that can be checked in less time than the full
search. Naive algorithms cost O(r^2) per trinomial, thus O(r^3) to search over
all trinomials of given degree r. Under a plausible assumption about the
distribution of factors of trinomials, the new algorithm has complexity O(r^2
(log r)^{3/2}(log log r)^{1/2}) for the search over all trinomials of degree r.
Our implementation achieves a speedup of greater than a factor of 560 over the
naive algorithm in the case r = 24036583 (a Mersenne exponent). Using our
program, we have found two new primitive trinomials of degree 24036583 over
GF(2) (the previous record degree was 6972593).


title: Cluster radioactivity of Th isotopes in the mean-field HFB theory

abstract:
  Cluster radioactivity is described as a very mass asymmetric fission process.
The reflection symmetry breaking octupole moment has been used in a mean field
HFB theory as leading coordinate instead of the quadrupole moment usually used
in standard fission calculations. The procedure has been applied to the study
of the ``very mass asymmetric fission barrier'' of several even-even Thorium
isotopes. The masses of the emitted clusters as well as the corresponding
half-lives have been evaluated on those cases where experimental data exist.


title:
Large-Scale Magnetic Field Re-generation by Resonant MHD Wave
  Interactions

abstract:
  We investigate numerically the long-time behavior of balanced Alfven wave
turbulence forced at intermediate scales. Whereas the usual constant-flux
solution is found at the smallest scales, two new scalings are obtained at the
forcing scales and at the largest scales of the system. In the latter case we
show, in particular, that the spectrum evolves first to a state determined by
Loitsyansky invariant and later a state close to the thermodynamic
equipartition solution predicted by wave turbulence. The astrophysical
implications for galactic magnetic field generation are discussed.


title: QCD Factorizations in Exclusive gamma* gamma* -> rho0_L rho0_L

abstract:
  The exclusive process e+ e- -> e+ e-rho0_L rho0_L allows to study various
dynamics and factorization properties of perturbative QCD. At moderate energy,
we demonstrate how collinear QCD factorization emerges, involving either
generalized distribution amplitudes (GDA) or transition distribution amplitudes
(TDA). At higher energies, in the Regge limit of QCD, we show that it offers a
promising probe of the BFKL resummation effects to be studied at ILC.


title: A remark on odd dimensional normalized Ricci flow

abstract:
  Let $(M^n,g_0)$ ($n$ odd) be a compact Riemannian manifold with
$\lambda(g_0)>0$, where $\lambda(g_0)$ is the first eigenvalue of the operator
$-4\Delta_{g_0}+R(g_0)$, and $R(g_0)$ is the scalar curvature of $(M^n,g_0)$.
Assume the maximal solution $g(t)$ to the normalized Ricci flow with initial
data $(M^n,g_0)$ satisfies $|R(g(t))| \leq C$ and $\int_M
|Rm(g(t))|^{n/2}d\mu_t \leq C$ uniformly for a constant $C$. Then we show that
the solution sub-converges to a shrinking Ricci soliton. Moreover,when $n=3$,
the condition $\int_M |Rm(g(t))|^{n/2}d\mu_t \leq C$ can be removed.


title: Proof of the combinatorial Kirillov-Reshetikhin conjecture

abstract:
  In this paper we give a direct proof of the equality of certain generating
function associated with tensor product multiplicities of Kirillov-Reshetikhin
modules for each simple Lie algebra g. Together with the theorems of Nakajima
and Hernandez, this gives the proof of the combinatorial version of the
Kirillov-Reshetikhin conjecture, which gives tensor product multiplicities in
terms of restricted fermionic summations.


title:
Direct calculation of the probability of pionium ionization in the
  target

abstract:
  We performed the first direct calculation of the probability of pionium
(pi+pi- atom) ionization in the target. The dependence of the probability of
pionium ionization in the target as a function of the pionium lifetime is
established. These calculations are of interest of the DIRAC experiment at
CERN, which aims to measure the pionium lifetime with high precision.


title: A particle acceleration site in the Coma cluster?

abstract:
  We present the results of a deep (1.1 Ms) observation of the Coma cluster of
galaxies in the 18-30 keV band with the IBIS/ISGRI imager on board the INTEGRAL
satellite. We show that the source extension in the North-East to South-West
(SW) direction ($\sim 17'$) significantly exceeds the size of the point spread
function of ISGRI, and that the centroid of the image of the source in the
18-30 keV band is displaced in the SW direction compared to the centroid in the
1-10 keV band. To test the nature of the SW extension we fit the data assuming
different models of source morphology. The best fit is achieved with a diffuse
source of elliptical shape, although an acceptable fit can be achieved assuming
an additional point source SW of the cluster core. In the case of an elliptical
source, the direction of extension of the source coincides with the direction
toward the subcluster falling onto the Coma cluster. If the SW excess is due to
the presence of a point source with a hard spectrum, we show that there is no
obvious X-ray counterpart for this additional source, and that the closest
X-ray source is the quasar EXO 1256+281, which is located $6.1'$ from the
centroid of the excess. Finally, we show that the hard X-ray emission coincides
with the 1.4 GHz radio emission, which suggests that the hard X-ray emission
comes from the same population of electrons that is responsible for radio
haloes through synchrotron emission.


title: Noncommutative Geometries and Gravity

abstract:
  We briefly review ideas about ``noncommutativity of space-time'' and
approaches toward a corresponding theory of gravity.


title:
Spin dynamics of a trapped spin-1 Bose Gas above the Bose-Einstein
  transition temperature

abstract:
  We study collective spin oscillations in a spin-1 Bose gas above the
Bose-Einstein transition temperature. Starting from the Heisenberg equation of
motion, we derive a kinetic equation describing the dynamics of a thermal gas
with the spin-1 degree of freedom. Applying the moment method to the kinetic
equation, we study spin-wave collective modes with dipole symmetry. The dipole
modes in the spin-1 system are found to be classified into the three type of
modes. The frequency and damping rate are obtained as functions of the peak
density. The damping rate is characterized by three relaxation times associated
with collisions.


title:
Fermion Systems in Discrete Space-Time Exemplifying the Spontaneous
  Generation of a Causal Structure

abstract:
  As toy models for space-time on the Planck scale, we consider examples of
fermion systems in discrete space-time which are composed of one or two
particles defined on two up to nine space-time points. We study the
self-organization of the particles as described by a variational principle both
analytically and numerically. We find an effect of spontaneous symmetry
breaking which leads to the emergence of a discrete causal structure.


title: A long-lived memory qubit on a low-decoherence quantum bus

abstract:
  We demonstrate long-lived coherence in internal hyperfine states of a single
\Ca{43} trapped-ion qubit $[T_2=1.2(2)\s]$, and in external motional states of
a single \Ca{40} trapped-ion qubit $[T_2'=0.18(4)\s]$, in the same apparatus.
The motional decoherence rate is consistent with the heating rate, which was
measured to be 3(1) quanta/sec. Long coherence times in the external motional
states are essential for performing high-fidelity quantum logic gates between
trapped-ion qubits. The internal-state $T_2$ time that we observe in \Ca{43},
which has not previously been used as a trapped-ion qubit, is about one
thousand times longer than that of physical qubits based on \Ca{40} ions. Using
a single spin-echo pulse to ``re-phase'' the internal state, we can detect no
decoherence after 1\s, implying an effective coherence time $T_2^{\mbox{\tiny
SE}} \gtish 45\s$. This compares with timescales in this trap for single-qubit
operations of \ish 1\us, and for two-qubit operations of \ish 10\us.


title: Lattice QCD approach to nuclear force

abstract:
  We present our updated results of the nucleon-nucleon potential in quenched
lattice QCD simulations with the plaquette gauge action and the Wilson quark
action on the 32^4(\simeq (4.4 fm)^4) lattice. From the equal-time
Bethe-Salpeter (BS) wave function, the NN potential is constructed through the
Schroedinger-type equation. Resulting NN potential has all the qualitative
features which phenomenological potentials commonly have: the repulsive core at
short distance and the attractive well at medium and long distances. In the L
\to \infty limit, our NN potential is guaranteed to reproduce the scattering
length obtained from the Luescher's formula. The quark mass dependence of the
NN potential is studied with m_{pi} \sim 380, 529, 731 MeV. The results suggest
that both the repulsive core at short distance and the attractive well at
medium distance are enhanced in the light quark mass region.


title:
Transverse momentum distributions of quarks from the lattice using
  extended gauge links

abstract:
  We present preliminary numerical studies in Lattice QCD related to the
intrinsic transverse momentum distribution of partons in the nucleon. We employ
non-local operators, consisting of spatially separated quark creation and
annihilation operators connected by a straight Wilson line. A clear signal is
already obtained from a small number of configurations at a pion mass of about
600 MeV. As an example, we demonstrate that we can obtain the first x-moment of
the transverse momentum dependent parton distribution function f_1^{n=1}(k_T)
from our data. Our results, which are not renormalized, show a Gaussian-like
distribution. The root mean squared transverse momentum is about 560 MeV for a
Gaussian fit, close to phenomenological values.


title: Valuations for matroid polytope subdivisions

abstract:
  We prove that the ranks of the subsets and the activities of the bases of a
matroid define valuations for the subdivisions of a matroid polytope into
smaller matroid polytopes.


title:
Gauge and constraint degrees of freedom: from analytical to numerical
  approximations in General Relativity

abstract:
  The harmonic formulation of Einstein's field equations is considered, where
the gauge conditions are introduced as dynamical constraints. The difference
between the fully constrained approach (used in analytical approximations) and
the free evolution one (used in most numerical approximations) is pointed out.
As a generalization, quasi-stationary gauge conditions are also discussed,
including numerical experiments with the gauge-waves testbed. The complementary
3+1 approach is also considered, where constraints are related instead with
energy and momentum first integrals and the gauge must be provided separately.
The relationship between the two formalisms is discussed in a more general
framework (Z4 formalism). Different strategies in black hole simulations follow
when introducing singularity avoidance as a requirement. More flexible
quasi-stationary gauge conditions are proposed in this context, which can be
seen as generalizations of the current 'freezing shift' prescriptions.


title:
Cohomological characterization of relative hyperbolicity and combination
  theorem

abstract:
  We give a cohomological characterization of Gromov relative hyperbolicity. As
an application we prove a converse to the combination theorem for graphs of
relatively hyperbolic groups given in a previous paper of the first author. We
build upon, and follow the ideas of, the work of S. Gersten in ``Cohom. lower
bounds for isoperim. funct. on groups'' (Topology 37, 1998) about the same
topics in the classical Gromov hyperbolic setting.


title: On the disconnection of a discrete cylinder by a biased random walk

abstract:
  We consider a random walk on the discrete cylinder
$({\mathbb{Z}}/N{\mathbb{Z}})^d\times{\mathbb{Z}}$, $d\geq3$ with drift
$N^{-d\alpha}$ in the $\mathbb{Z}$-direction and investigate the large
$N$-behavior of the disconnection time $T^{\mathrm{disc}}_N$, defined as the
first time when the trajectory of the random walk disconnects the cylinder into
two infinite components. We prove that, as long as the drift exponent $\alpha$
is strictly greater than 1, the asymptotic behavior of $T^{\mathrm{disc}}_N$
remains $N^{2d+o(1)}$, as in the unbiased case considered by Dembo and
Sznitman, whereas for $\alpha<1$, the asymptotic behavior of
$T^{\mathrm{disc}}_N$ becomes exponential in $N$.


title: Nonlinear theory of mirror instability near threshold

abstract:
  An asymptotic model based on a reductive perturbative expansion of the drift
kinetic and the Maxwell equations is used to demonstrate that, near the
instability threshold, the nonlinear dynamics of mirror modes in a magnetized
plasma with anisotropic ion temperatures involves a subcritical
bifurcation,leading to the formation of small-scale structures with amplitudes
comparable with the ambient magnetic field.


title:
On photoionization of the subvalent subshells of noble gas endohedral
  atoms

abstract:
  We demonstrate strong interference patterns in the photoionization
cross-section of the subvalent subshells of noble gas (NG) endohedral atoms
NG@F. This interference is a result of common action of three factors: the
effect of neighboring atomic subshells, reflection of photoelectron waves by
the fullerene F shell and resonance modification of the incoming photon beam by
the complex effect under the action of the F electrons.
  We have considered the outer ns-subshells for Ne, Ar, Kr and Xe noble gas
atoms. The polarization of the fullerene shell is expressed via the F total
photoabsorption cross section. The photoelectron reflection from the static F
potential is taken into account in the frame of the so-called bubble potential
that is a spherical zero--thickness type potential.
  It is assumed in the derivations that NG is centrally located in the
fullerene. It is assumed also, in accordance with the available experimental
data, that the fullerene radius is much bigger than the atomic radius and the
thickness of the fullerene shell. These assumptions permit, as demonstrated
recently, the NG@F photoionization cross section to be presented as a product
of the NG subvalent cross section and two calculated factors that account for
polarization of the F electron shell and reflection of photoelectrons by the
fullerene static potential.


title: Unparticles and CP-violation

abstract:
  We give a brief summary of the unparticle scenario proposed by Georgi. The
CP-even phase of the propagator is exploited to study the CP-asymmetry in B+
--> tau+ + nu, which is neither experimentally searched for nor predicted by
any other model. Furthermore we show that the novel CP-violation is consistent
with the CPT theorem by identifying the CP-compensating mode in the unparticle
sector.


title: Heterogeneous Condensation

abstract:
  Vapor condensation on nanoparticle with radius smaller than the Kelvin radius
is considered as fluctuation or as the heterogeneous nucleation. The expression
for steady-state heterogeneous nucleation rate is obtained. Nucleation on
negatively charged nanoparticles is discussed. The report was made at 17th
International Nucleation and Atmospheric Conferences, Galway, Ireland, 2007.


title:
On the Role of the Normalization Factors $\kappa_n$ and of the
  Pseudo-Metric ${\cal P} \neq {\cal P}^\dagger$ in Crypto-Hermitian Quantum
  Models

abstract:
  Among ${\cal P}$-pseudo-Hermitian Hamiltonians $H ={\cal P}^{-1} H^\dagger
\cal P}$ with real spectra, the ''weakly pseudo-Hermitian" ones (i.e., those
employing non-self-adjoint ${\cal P} \neq {\cal P}^\dagger$) form a remarkable
subfamily. We list some reasons why it deserves a special attention. In
particular we show that whenever ${\cal P} \neq {\cal P}^\dagger$, the current
involutive operator of charge ${\cal C}$ gets complemented by a nonequivalent
alternative involutive quasiparity operator ${\cal Q}$. We show how, in this
language, the standard quantum mechanics is restored via the two alternative
inner products in the physical Hilbert space of states, with $<\psi_1|{\cal
PQ}|\psi_2>=< \psi_1|{\cal CP}|\psi_2>$.


title: Hot electrons induced by (rather) cold ions

abstract:
  Thin film metal-insulator-metal junctions are used in a novel approach to
investigate the dissipation of potential energy of multiply charged ions
impinging on a polycrystalline metal surface. The ion-metal interaction leads
to excited electrons and holes within the top layer. A substantial fraction of
these charge carriers is transported inwards and can be measured as an internal
current in the thin film tunnel junction. In Ag-AlOX-Al junctions, yields of
typically 0.1-1 electrons per impinging ion are detected in the bottom Al
layer. The separate effects of potential and kinetic energy on the tunneling
yield are investigated by varying the charges state of the Ar projectile ions
from 2+ to 9+ for kinetic energies in the range from 1 to 12 keV. The tunneling
yield is found to scale linearly with the potential energy of the projectile.


title: Lectures on the three--dimensional non--commutative spheres

abstract:
  These are expanded notes for a short course given at the Universidad Nacional
de La Plata. They aim at giving a self-contained account of the results of
Alain Connes and Michel Dubois--Violette.


title:
Manifestation of spin-orbit interaction in tunneling between 2D electron
  layers

abstract:
  An influence of spin-orbit interaction on the tunneling between two 2D
electron layers is considered. Particular attention is addressed to the
relation between the contribution of Rashba and Dresselhaus types. It is shown
that without scattering of the electrons, the tunneling conductance can either
exhibit resonances at certain voltage values or be substantially suppressed
over the whole voltage range. The dependence of the conductance on voltage
turns out to be very sensitive to the relation between Rashba and Dresselhaus
contributions even in the absence of magnetic field. The elastic scattering
broadens the resonances in the first case and restores the conductance to a
larger magnitude in the latter one. These effects open possibility to determine
the parameters of spin-orbit interaction and electrons scattering time in
tunneling experiments with no necessity of external magnetic field.


title:
Thermodynamic Casimir effects involving interacting field theories with
  zero modes

abstract:
  Systems with an O(n) symmetrical Hamiltonian are considered in a
$d$-dimensional slab geometry of macroscopic lateral extension and finite
thickness $L$ that undergo a continuous bulk phase transition in the limit
$L\to\infty$. The effective forces induced by thermal fluctuations at and above
the bulk critical temperature $T_{c,\infty}$ (thermodynamic Casimir effect) are
investigated below the upper critical dimension $d^*=4$ by means of
field-theoretic renormalization group methods for the case of periodic and
special-special boundary conditions, where the latter correspond to the
critical enhancement of the surface interactions on both boundary planes. As
shown previously [\textit{Europhys. Lett.} \textbf{75}, 241 (2006)], the zero
modes that are present in Landau theory at $T_{c,\infty}$ make conventional
RG-improved perturbation theory in $4-\epsilon$ dimensions ill-defined. The
revised expansion introduced there is utilized to compute the scaling functions
of the excess free energy and the Casimir force for temperatures
$T\geqT_{c,\infty}$ as functions of $\mathsf{L}\equiv L/\xi_\infty$, where
$\xi_\infty$ is the bulk correlation length. Scaling functions of the
$L$-dependent residual free energy per area are obtained whose $\mathsf{L}\to0$
limits are in conformity with previous results for the Casimir amplitudes
$\Delta_C$ to $O(\epsilon^{3/2})$ and display a more reasonable
small-$\mathsf{L}$ behavior inasmuch as they approach the critical value
$\Delta_C$ monotonically as $\mathsf{L}\to 0$.


title: Homotopy dimension of orbits of Morse functions on surfaces

abstract:
  Let $f$ be a real- or circle-valued Morse function on a compact surface M
having exactly $n>0$ critical points. Denote by $O$ the orbit of $f$ with
respect to the right action of the group of diffeomorphisms of $M$. We show
that the connected components of $O$ have the homotopy type of a
finite-dimensional CW-complex. Actually, these connected components are
homotopy equivalent to a certain covering space of the $n$-th configuration
space of the interior of $M$. As a consequence we obtain that the fundamental
group of $O$ is a subgroup of the $n$-th braid group of $M$.


title: Modified Actions for Gravity: Theory and Phenomenology

abstract:
  This thesis is devoted to the study of gravitational theories which can be
seen as modifications or generalisations of General Relativity. The motivation
for considering such theories, stemming from Cosmology, High Energy Physics and
Astrophysics is thoroughly discussed (cosmological problems, dark energy and
dark matter problems, the lack of success so far in obtaining a successful
formulation for Quantum Gravity). The basic principles which a gravitational
theory should follow, and their geometrical interpretation, are analysed in a
broad perspective which highlights the basic assumptions of General Relativity
and suggests possible modifications which might be made. A number of such
possible modifications are presented, focusing on certain specific classes of
theories: scalar-tensor theories, metric f(R) theories, Palatini f(R) theories,
metric-affine f(R) theories and Gauss--Bonnet theories. The characteristics of
these theories are fully explored and attention is payed to issues of dynamical
equivalence between them. Also, cosmological phenomenology within the realm of
each of the theories is discussed and it is shown that they can potentially
address the well-known cosmological problems. A number of viability criteria
are presented: cosmological observations, Solar System tests, stability
criteria, existence of exact solutions for common vacuum or matter
configurations etc. Finally, future perspectives in the field of modified
gravity are discussed and the possibility for going beyond a trial-and-error
approach to modified gravity is explored.


title:
Supersymmetric Interpretation of the EGRET Excess in Diffuse Galactic
  Gamma Rays

abstract:
  Recently it was shown that the excess of diffuse Galactic gamma rays above 1
GeV could be interpreted as a Dark Matter annihilation signal. From the
spectral shape of the excess it is possible to determine a range for the
allowed WIMP mass which can be used to test the supersymmetric parameter space.
It is found that the EGRET excess combined with electroweak and other
constraints, e.g. relic denisity or direct detection limits, is fully
consistent with the minimal mSUGRA model for scalars in the TeV range and
gauginos below 500 GeV.


title:
Role of symmetry in the interplay of T=0 quantum-phase transitions with
  unconventional T>0 transport properties in integrable quantum lattice systems

abstract:
  We show that a generalized charge SU(2) symmetry of the one-dimensional (1D)
Hubbard model in an infinitesimal flux $\phi$ generates half-filling states
from metallic states which lead to a finite charge stiffness $D(T)$ at finite
temperature $T$, whose $T$ dependence we study. Our results are of general
nature for many integrable quantum lattice systems, reveal the microscopic
mechanisms behind their exotic $T>0$ transport properties and the interplay
with T=0 quantum-phase transitions, and contribute to the further understanding
of the transport of charge in systems of interacting ultracold fermionic atoms
in 1D optical lattices, quasi-1D compounds, and 1D nanostructures.


title: Calabi-Yau cones from contact reduction

abstract:
  We consider a generalization of Einstein-Sasaki manifolds, which we
characterize in terms both of spinors and differential forms, that in the real
analytic case corresponds to contact manifolds whose symplectic cone is
Calabi-Yau. We construct solvable examples in seven dimensions. Then, we
consider circle actions that preserve the structure, and determine conditions
for the contact reduction to carry an induced structure of the same type. We
apply this construction to obtain a new hypo-contact structure on S^2\times
T^3.


title:
Neutron star sequences and the starquake glitch model for the Crab and
  the Vela pulsars

abstract:
  We construct for the first time, the sequences of stable neutron star (NS)
models capable of explaining simultaneously, the glitch healing parameters,
$Q$, of both the pulsars, the Crab ($Q \geq 0.7$) and the Vela ($Q \leq 0.2$),
on the basis of starquake mechanism of glitch generation, whereas the
conventional NS models cannot give such consistent explanation. Furthermore,
our models also yield an upper bound on NS masses similar to those obtained in
the literature for a variety of modern equations of state (EOSs) compatible
with causality and dynamical stability. The results obtained in this paper set
an upper and lower bound on the energy of a gravitationally redshifted
electron-positron annihilation line in the range of about 0.309 - 0.315 MeV
from the Crab and in the range of about 0.425 - 0.439 MeV from the Vela pulsar.


title:
Are neutrino masses dynamically generated by quantum gravity
  attractions?

abstract:
  It is argued that the quantum gravity attractions dynamically generate tiny
degenerate Majorana masses for the neutrinos. The unequal masses of the charged
leptons then induce a computable neutrino mass matrix with splittings and
mixings through the electroweak interactions. In this way the Standard Model
including quantum gravity can accommodate and predict the neutrino masses and
mixings. Some consequences are pointed out.