title:
A Yukawa coupling parameterization for type I+ II seesaw formula and
  applications to lepton flavor violation and leptogenesis

abstract:
  In the type I + II seesaw formula the mass matrix of light neutrinos m_nu
receives contributions from the exchanges of both heavy Majorana neutrinos and
SU(2)_L-triplet Higgs bosons. We propose a new parameterization for the
Dirac-type Yukawa coupling matrix of neutrinos in this case, which generalizes
the well known Casas-Ibarra parameterization to type I + II seesaw and is
useful when the triplet term in m_nu is known. Neutrino masses and mixing,
lepton flavor violation in decays like mu -> e \gamma within mSUGRA models and
leptogenesis can then be studied within this framework. We illustrate the
usefulness of our new parameterization using a number of simple examples.


title:
Coupled charge and valley excitations in graphene quantum Hall
  ferromagnets

abstract:
  Graphene is a two-dimensional carbon material with a honeycomb lattice and
Dirac-type low-energy spectrum. In a strong magnetic field, where Coulomb
interactions dominate against disorder broadening, quantum Hall ferromagnetic
states realize at integer fillings. Extending the quantum Hall ferromagnetism
to the fractional filling case of massless Dirac fermions, we study the
elementally charge excitations which couple with the valley degrees of freedom
(so-called valley skyrmions). With the use of the density matrix renomalization
group (DMRG) method, the excitation gaps are calculated and extrapolated to the
thermodynamic limit. These results exhibit numerical evidences and criterions
of the skyrmion excitations in graphene.


title: Haptic guidance improves the visuo-manual tracking of trajectories

abstract:
  BACKGROUND: Learning to perform new movements is usually achieved by
following visual demonstrations. Haptic guidance by a force feedback device is
a recent and original technology which provides additional proprioceptive cues
during visuo-motor learning tasks. The effects of two types of haptic
guidances-control in position (HGP) or in force (HGF)-on visuo-manual tracking
("following") of trajectories are still under debate. METHODOLOGY/PRINCIPALS
FINDINGS: Three training techniques of haptic guidance (HGP, HGF or control
condition, NHG, without haptic guidance) were evaluated in two experiments.
Movements produced by adults were assessed in terms of shapes (dynamic time
warping) and kinematics criteria (number of velocity peaks and mean velocity)
before and after the training sessions. CONCLUSION/SIGNIFICANCE: These results
show that the addition of haptic information, probably encoded in force
coordinates, play a crucial role on the visuo-manual tracking of new
trajectories.


title:
Dimensional and temperature dependence of metal insulator transition in
  correlated and disordered systems

abstract:
  We study the dimensional dependence of the interplay between correlation and
disorder in two dimension at half filling using 2D $t-t'$ disordered Hubbard
model with deterministic disorder both at zero and finite temperatures.
Inclusion of $t'$ without disorder leads to a metallic phase at half filling
below a certain critical value of $U$. Above this critical value $U_c$
correlation favours antiferromagnetic phase. Since disorder leads to double
occupancy over the lower energy site, the competition between Hubbard $U$ and
disorder leads to the emergence of a metallic phase, which can be quantified by
the calculation of Kubo conductivity, gap at half-filling, density of states,
spin order parameter, Inverse participation ratio (IPR) and bandwidth. We have
studied the effect of disorder on the system in a very novel way through a
deterministic disorder which follows a Fibonacci sequence. Behaviour of
different parameters show interesting features on going from a two to quasi one
dimensional system.


title: Particle multiplicities and particle ratios in excluded volume model

abstract:
  One of the most surprising results is to find that a consistent description
of all the experimental results on particle multiplicities and particle ratios
obtained from the lowest AGS to the highest RHIC energies is possible within
the framework of a thermal statistical model. We propose here a
thermodynamically consistent excluded-volume model involving an interacting
multi-component hadron gas. We find that the energy dependence of the total
multiplicities of strange and non-strange hadrons obtained in this model agrees
closely with the experimental results. It indicates that the freeze out volume
of the fireball is uniformly the same for all the particles. We have also
compared the variation of the particle ratios such as $<K^{+}>/<\pi^{+}>, <
K^{-}>/<\pi^{-}>, K^{-}/K^{+}, \bar{p}/p, \bar{\Lambda}/\Lambda, \bar{\Xi}/\Xi,
\bar{\Omega}/\Omega, < \Lambda>/<\pi>, <\Xi^{-}>/<\pi>,
<\Omega+\bar{\Omega}>/<\pi>$ and $<\Phi>/<\pi>$ with respect to the
center-of-mass energy as predicted by our model with the recent experimental
data.


title: BCS-BEC crossover in dense relativistic matter: Collective excitations

abstract:
  We study the relativistic BCS-BEC crossover within a class of
Nambu-Jona-Lasinio type models, including arbitrary Lorentz-scalar pairing
channels. Using the mean-field approximation we investigate spectral properties
of the collective bosonic excitations in the superfluid phase, with particular
attention to the Nambu--Goldstone bosons of the broken symmetry. This is a
first step towards a systematic improvement of the mean-field approximation by
including the fluctuation effects. The general results are illustrated on
pairing in dense two-flavor quark matter - the two-flavor color superconductor.


title: Standard Character Condition for C-algebras

abstract:
  It is well known that the adjacency algebra of an association scheme has the
standard character. In this paper we first define the concept of standard
character for C-algebras and we say that a C-algebra has the {\it standard
character condition} if it has the standard character. Then we investigate some
properties of C-algebras which have the standard character condition and prove
that under some conditions a C-algebra has an adjacency algebra homomorphic
image. In particular, we obtain a necessary and sufficient condition for which
a commutative table algebra comes from an association scheme.


title: Ergodic Theory: Nonsingular Transformations

abstract:
  This survey is an update of the 2008 version, with recent developments and
new references.


title:
Space-like Separation in a Bell Test assuming Gravitationally Induced
  Collapses

abstract:
  We report on a Bell experiment with space-like separation assuming that the
measurement time is related to gravity-induced state reduction. Two energy-time
entangled photons are sent through optical fibers and directed into unbalanced
interferometers at two receiving stations separated by 18 km. At each station,
the detection of a photon triggers the displacement of a macroscopic mass. The
timing ensures space-like separation from the moment a photon enters its
interferometer until the mass has moved. 2-photon interference fringes with a
visibility of up to 90.5% are obtained, leading to a violation of Bell
inequality.


title:
Partially Locked States in Coupled Oscillators due to Inhomogeneous
  Coupling

abstract:
  We investigate coupled identical phase oscillators with scale-free
distribution of coupling strength. It is shown that partially locked states can
occur due to the inhomogeneity in coupling and some properties of the coupling
function. Various quantities of the partially locked states are computed
through a self-consistency argument and the values show good agreement with
simulation results.


title:
A General Rate Duality of the MIMO Multiple Access Channel and the MIMO
  Broadcast Channel

abstract:
  We present a general rate duality between the multiple access channel (MAC)
and the broadcast channel (BC) which is applicable to systems with and without
nonlinear interference cancellation. Different to the state-of-the-art rate
duality with interference subtraction from Vishwanath et al., the proposed
duality is filter-based instead of covariance-based and exploits the arising
unitary degree of freedom to decorrelate every point-to-point link. Therefore,
it allows for noncooperative stream-wise decoding which reduces complexity and
latency. Moreover, the conversion from one domain to the other does not exhibit
any dependencies during its computation making it accessible to a parallel
implementation instead of a serial one. We additionally derive a rate duality
for systems with multi-antenna terminals when linear filtering without
interference (pre-)subtraction is applied and the different streams of a single
user are not treated as self-interference. Both dualities are based on a
framework already applied to a mean-square-error duality between the MAC and
the BC. Thanks to this novel rate duality, any rate-based optimization with
linear filtering in the BC can now be handled in the dual MAC where the arising
expressions lead to more efficient algorithmic solutions than in the BC due to
the alignment of the channel and precoder indices.


title: Linearisation of conservative toral homeomorphisms

abstract:
  We give an equivalent characterisation for the existence of a semi-conjugacy
to an irrational rotation for conservative homeomorphisms of the two-torus.
This leads to an analogue of Poincare's classification of circle homeomorphisms
for conservative toral homeomorphisms with unique rotation vector and a certain
bounded mean motion property. For minimal toral homeomorphisms, the result
extends to arbitrary dimensions. Further, we provide a basic classification for
the dynamics of non-wandering toral homeomorphisms homotopic to the identitiy.


title: On partita doppia

abstract:
  We give a precise mathematical account of partita doppia in terms of an
algebraic structure on the bicategory of spans of reflexive graphs. (The paper
was written in 1998.)


title: The Nichols algebra of a semisimple Yetter-Drinfeld module

abstract:
  We study the Nichols algebra of a semisimple Yetter-Drinfeld module and
introduce new invariants such as real roots. The crucial ingredient is a
`reflection' in the class of such Nichols algebras. We conclude the
classifications of finite-dimensional pointed Hopf algebras over S_3, and of
finite-dimensional Nichols algebras over S_4.
  The revised version contains an extended introduction with references to
recent applications, and a simplified definition of the Weyl groupoid of a
semisimple Yetter-Drinfeld module.
  Key words: Hopf algebras, quantum groups, Weyl groupoid


title: Alday-Maldacena duality and AdS Plateau problem

abstract:
  A short summary of approximate approach to the study of minimal surfaces in
AdS, based on solving Nambu-Goto equations iteratively. Today, after partial
denunciation of the BDS conjecture, this looks like the only constructive
approach to understanding the ways of its possible modification and thus to
saving the Alday-Maldacena duality. Numerous open technical problems are
explicitly formulated throughout the text.


title: Matching the Local and Cosmic Star Formation Histories

abstract:
  Given the many recent advances in our understanding of the star formation
history (SFH) of the Local Group and other nearby galaxies, and in the
evolution of star formation with redshift, we present a new comparison of the
comoving space density of the star formation rate as a function of look-back
time for the Local and Distant Universe. We update the Local SFH derived from
the analysis of resolved stellar populations (``fossil records'') in individual
nearby galaxies, based on our own estimations as well as available in the
literature. While the preliminary comparison of SFHs is found to be broadly
consistent, some discrepancies still remain, including an excess of the Local
SFR density in the most recent epoch.


title: Acyclic Edge colorings of 2-degenerate graphs

abstract:
  An $acyclic$ edge coloring of a graph is a proper edge coloring such that
there are no bichromatic cycle s. The \emph{acyclic chromatic index} of a graph
is the minimum number k such that there is an acyclic e dge coloring using k
colors and is denoted by $a'(G)$. A graph is called 2-$degenerate$ if any of
its induced subgraph has a vertex of degree at most 2. The class of
2-$degenerate graphs$ properly conta in $series$-$parallel graphs$,
$outerplanar graphs$, \emph{non-regular subcubic graphs}, \emph{planar graphs
of girth at least 6} and \emph{circle graphs of girth at least 5} as
subclasses. It was conjectur ed by Alon, Sudakov and Zaks (and earlier by
Fiamcik) that $a'(G)\le \Delta+2$, where $\Delta =\Delta(G)$ denotes the
maximum deg ree of the graph. We prove the conjecture for 2-$degenerate$
graphs: in fact we prove a stronger bound . We prove that if $G$ is a
2-degenerate graph with maximum degree $\Delta$, then $a'(G)\le \Delta + 1$.


title: Global stucture of webs in codimension one

abstract:
  We describe the global structure of holomorphic webs in codimension one, and
in particular their singularity (caustic). Various concepts are introduced,
which have no interest locally near a regular point, such as the type, the
reducibility, the quasi-smoothness, the CI property (complete intersection),
the dicriticity... We prove for instance that the algebraicity of a web
globally defined on a complex projective space may be readen on its caustic
(dicriticity), at least if each irreducible component is CI, and the web
quasi-smooth. .


title:
Synchrotron superbubble in the galaxy IC10: the ionized gas structure,
  kinematics, and emission spectrum

abstract:
  We have investigated the structure, kinematics, and emission spectrum of the
ionized gas in the synchrotron superbubble in the irregular galaxy IC 10 based
on observations with the 6-m Special Astrophysical Observatory telescope with
the SCORPIO focal reducer in three modes: direct imaging in the
[SII](6717+6731)A lines, long-slit spectroscopy, and spectroscopy with a
scanning Fabry--Perot interferometer. We have identified a bright (in the [SII]
lines) filamentary optical shell and determined its expansion velocity, mass,
and kinetic energy. The nature of the object is discussed.


title: Semi-classical analysis and passive imaging

abstract:
  Passive imaging is a new technique which has been proved to be very
efficient, for example in seismology: the correlation of the noisy fields,
computed from the fields recorded at different points, is strongly related to
the Green function of the wave propagation. The aim of this paper is to provide
a mathematical context for this approach and to show, in particular, how the
methods of semi-classical analysis can be be used in order to find the
asymptotic behaviour of the correlations.


title:
Perturbative solutions to the extended constant scalar curvature
  equations on asymptotically hyperbolic manifolds

abstract:
  We prove local existence of solutions to the extended constant scalar
curvature equations introduced by A. Butscher, in the asymptotically hyperbolic
setting. This gives a new local construction of asymptotically hyperbolic
metrics with constant scalar curvature.


title: Metrics With Vanishing Quantum Corrections

abstract:
  We investigate solutions of the classical Einstein or supergravity equations
that solve any set of quantum corrected Einstein equations in which the
Einstein tensor plus a multiple of the metric is equated to a symmetric
conserved tensor $T_{\mu \nu}$ constructed from sums of terms the involving
contractions of the metric and powers of arbitrary covariant derivatives of the
curvature tensor. A classical solution, such as an Einstein metric, is called
{\it universal} if, when evaluated on that Einstein metric, $T_{\mu \nu}$ is a
multiple of the metric. A Ricci flat classical solution is called {\it strongly
universal} if, when evaluated on that Ricci flat metric, $T_{\mu \nu}$
vanishes. It is well known that pp-waves in four spacetime dimensions are
strongly universal. We focus attention on a natural generalisation; Einstein
metrics with holonomy ${\rm Sim} (n-2)$ in which all scalar invariants are zero
or constant. In four dimensions we demonstrate that the generalised
Ghanam-Thompson metric is weakly universal and that the Goldberg-Kerr metric is
strongly universal; indeed, we show that universality extends to all
4-dimensional ${\rm Sim}(2)$ Einstein metrics. We also discuss generalizations
to higher dimensions.


title: Joule expansion of a pure many-body state

abstract:
  We derive the Joule expansion of an isolated perfect gas from the principles
of quantum mechanics. Contrary to most studies of irreversible processes which
consider composite systems, the gas many-body Hilbert space cannot be
factorised into Hilbert spaces corresponding to interesting and ignored degrees
of freedom. Moreover, the expansion of the gas into the entire accessible
volume is obtained for pure states. Still, the number particle density is
characterised by a chemical potential and a temperature. We discuss the special
case of a boson gas below the Bose condensation temperature.


title: Spin transfer torques in nonlocal lateral spin valve

abstract:
  We report a theoretical study on the spin and electron transport in the
nonlocal lateral spin valve with non-collinear magnetic configuration. The
nonlocal magnetoresistance, defined as the voltage difference on the detection
lead over the injected current, is derived analytically. The spin transfer
torques on the detection lead are calculated. It is found that spin transfer
torques are symmetrical for parallel and antiparallel magnetic configurations,
which is different from that in conventional sandwiched spin valve.


title:
On a Szego Type Limit Theorem, the Holder-Young-Brascamp-Lieb
  Inequality, and the Asymptotic Theory of Integrals and Quadratic Forms of
  Stationary Fields

abstract:
  Many statistical applications require establishing central limit theorems for
sums, integrals, or for quadratic forms of functions of a stationary process. A
particularly important case is that of Appell polynomials, since the Appell
expansion rank" determines typically the type of central limit theorem
satisfied by these functionals. We review and extend here to multidimensional
indices a functional analysis approach to this problem proposed by Avram and
Brown (1989), based on the method of cumulants and on integrability assumptions
in the spectral domain; several applications are presented as well.


title: d-wave collapse and explosion of a dipolar Bose-Einstein condensate

abstract:
  We investigate the collapse dynamics of a dipolar condensate of 52Cr atoms
when the s-wave scattering length characterizing the contact interaction is
reduced below a critical value. A complex dynamics, involving an anisotropic,
d-wave symmetric explosion of the condensate, is observed. The atom number
decreases abruptly during the collapse. We find good agreement between our
experimental results and those of a numerical simulation of the
three-dimensional Gross-Pitaevskii equation, including contact and dipolar
interactions as well as three-body losses. The simulation indicates that the
collapse induces the formation of two vortex rings with opposite circulations.


title:
Discrete stochastic processes, replicator and Fokker-Planck equations of
  coevolutionary dynamics in finite and infinite populations

abstract:
  Finite-size fluctuations in coevolutionary dynamics arise in models of
biological as well as of social and economic systems. This brief tutorial
review surveys a systematic approach starting from a stochastic process
discrete both in time and state. The limit $N\to \infty$ of an infinite
population can be considered explicitly, generally leading to a replicator-type
equation in zero order, and to a Fokker-Planck-type equation in first order in
$1/\sqrt{N}$. Consequences and relations to some previous approaches are
outlined.

categories: q-bio.PE cond-mat.stat-mech cs.SI math.PR math.ST physics.bio-ph physics.soc-ph stat.TH


title: Casimir energy between a plane and a sphere in electromagnetic vacuum

abstract:
  The Casimir energy is computed in the geometry of interest for the most
precise experiments, a plane and a sphere in electromagnetic vacuum. The
scattering formula is developed on adapted plane-waves and multipole basis,
leading to an expression valid for arbitrary relative values of the sphere
radius and inter-plate distance. In the limiting case of perfect reflection,
the electromagnetic result is found to depart from the commonly used
proximity-force approximation (PFA) significantly more rapidly than expected
from scalar computations.


title: Dispelling the antihydrogen myth

abstract:
  While achiral Bohr atom theory cannot generate Hbar signatures, achiral
Heitler-London bond theory can but its Hbar signatures must be detected. We
show that the largest spectral signature to probe Hbar is the singlet-triplet
splitting of 9,5 eV at r(0)=0,74 Angstrom, observed in the dihydrogen band
spectrum. This large Hbar-signature, overlooked for nearly a century, is
confirmed with the observed HH potential energy curve. Hbar claims by
CERN-based collaborations, seemingly important for the fate and future of Hbar,
are premature and must be examined critically.


title: Low-energy excitations of a boson pair in a double-well trap

abstract:
  The states of a boson pair in a one-dimensional double-well potential are
investigated. Properties of the ground and lowest excited states of this system
are studied, including the two-particle wavefunction, momentum pair
distribution and entanglement. The effects of varying both the barrier height
and the effective interaction strength are investigated.


title:
Trajectory Networks and Their Topological Changes Induced by
  Geographical Infiltration

abstract:
  In this article we investigate the topological changes undergone by
trajectory networks as a consequence of progressive geographical infiltration.
Trajectory networks, a type of knitted network, are obtained by establishing
paths between geographically distributed nodes while following an associated
vector field. For instance, the nodes could correspond to neurons along the
cortical surface and the vector field could correspond to the gradient of
neurotrophic factors, or the nodes could represent towns while the vector
fields would be given by economical and/or geographical gradients. Therefore
trajectory networks are natural models of a large number of geographical
structures. The geographical infiltrations correspond to the addition of new
local connections between nearby existing nodes. As such, these infiltrations
could be related to several real-world processes such as contaminations,
diseases, attacks, parasites, etc. The way in which progressive geographical
infiltrations affect trajectory networks is investigated in terms of the
degree, clustering coefficient, size of the largest component and the lengths
of the existing chains measured along the infiltrations. It is shown that the
maximum infiltration distance plays a critical role in the intensity of the
induced topological changes. For large enough values of this parameter, the
chains intrinsic to the trajectory networks undergo a collapse which is shown
not to be related to the percolation of the network also implied by the
infiltrations.


title:
Stroboscopic wavepacket description of non-equilibrium many-electron
  problems

abstract:
  We introduce the construction of a orthogonal wavepacket basis set, using the
concept of stroboscopic time propagation, tailored to the efficient description
of non-equilibrium extended electronic systems. Thanks to three desirable
properties of this basis, significant insight is provided into non-equilibrium
processes (both time-dependent and steady-state), and reliable physical
estimates of various many-electron quantities such as density, current and spin
polarization can be obtained. The use of this novel tool is demonstrated for
time-dependent switching-on of the bias in quantum transport, and new results
are obtained for current-induced spin accumulation at the edge of a 2D doped
semiconductor caused by edge-induced spin-orbit interaction.


title:
Transverse Velocity Dependence of the Proton-Antiproton Ratio as a
  Signature of the QCD Critical Endpoint

abstract:
  The presence of a critical point in the QCD phase diagram can deform the
trajectories describing the evolution of the expanding fireball in the
$\mu_B-T$ phase diagram. If the average emission time of hadrons is a function
of transverse velocity, as microscopic simulations of the hadronic freeze-out
dynamics suggest, the deformation of the hydrodynamic trajectories will change
the transverse velocity ($\beta_{\rm T}$) dependence of the proton-antiproton
ratio when the fireball passes in the vicinity of the critical point. An
unusual $\beta_{\rm T}$-dependence of the $\bar{p}/p$ ratio in a narrow beam
energy window would thus signal the presence of the critical point.


title:
Global well posedness and inviscid limit for the Korteweg-de
  Vries-Burgers equation

abstract:
  Considering the Cauchy problem for the Korteweg-de Vries-Burgers equation
\begin{eqnarray*} u_t+u_{xxx}+\epsilon |\partial_x|^{2\alpha}u+(u^2)_x=0, \
u(0)=\phi, \end{eqnarray*} where $0<\epsilon,\alpha\leq 1$ and $u$ is a
real-valued function, we show that it is globally well-posed in $H^s\
(s>s_\alpha)$, and uniformly globally well-posed in $H^s (s>-3/4)$ for all
$\epsilon \in (0,1)$. Moreover, we prove that for any $T>0$, its solution
converges in $C([0,T]; H^s)$ to that of the KdV equation if $\epsilon$ tends to
0.


title:
New descriptions of lattice SU(N) Yang-Mills theory towards quark
  confinement

abstract:
  We give new descriptions of lattice SU(N) Yang-Mills theory in terms of new
lattice variables. The validity of such descriptions has already been
demonstrated in the SU(2) Yang-Mills theory by our previous works from the
viewpoint of defining and extracting topological degrees of freedom such as
gauge-invariant magnetic monopoles and vortices which play the dominant role in
quark confinement. In particular, we have found that the SU(3) lattice
Yang-Mills theory has two possible options, maximal and minimal: The existence
of the minimal option has been overlooked so far, while the maximal option
reproduces the conventional SU(3) Cho-Faddeev-Niemi-Shabanov decomposition in
the naive continuum limit. The new description gives an important framework for
understanding the mechanism of quark confinement based on the dual
superconductivity.


title:
Electromagnetic response and pseudo-zero-mode Landau levels of bilayer
  graphene in a magnetic field

abstract:
  The electromagnetic response of bilayer graphene in a magnetic field is
studied in comparison with that of monolayer graphene. Both types of graphene
turn out to be qualitatively quite similar in dielectric and screening
characteristics, especially those deriving from vacuum fluctuations, but the
effect is generally much more sizable for bilayers. The presence of the
zero-(energy-)mode Landau levels is a feature specific to graphene. In
bilayers, unlike in monolayers, the effect of the zero-mode levels becomes
visible and even dominant in density response as an externally-controllable
band gap develops. It is pointed out that the splitting of nearly-degenerate
pseudo-zero-mode levels at each valley, specific to bilayer graphene, is
controlled by an applied inplane electric field or by an injected current. In
addition, a low-energy effective gauge theory of bilayer graphene is
constructed.


title:
Sociophysics and the Forming of Public Opinion: Threshold versus Non
  Threshold Dynamics

abstract:
  A two state model for opinion forming, which has proven heuristic power, is
reviewed with a novel emphasis on the existence or absence of a threshold for
the dynamics. Monitored by repeated small groups discussions floater agents
update their opinion according to a local majority rule. A threshold makes the
initial supports to flow towards eitheir one of two opposite attractors with
only one single opinion. While odd sizes yield a threshold at fifty percent
even sizes, which allow the inclusion of doubt at an opinion tie, produces a
threshold shift toward either 0 or 1 giving rise to minority opinion spreading.
Considering heterogeneous agents like contrarians and inflexibles turn the
dynamics threshold less beyond sone critical values. One unique attractor at
fifty-fifty drives then the dynamics. In addition inflexibles can generate
asymmetry and if one sided they erase the threshold ensuring the associated
opinion to eventually gain the all population support. It may shed a new and
counter intuitive light on some social aspect of the global warming phenomenon.


title: Finite Generation of Canonical Ring by Analytic Method

abstract:
  In the 80th birthday conference for Professor LU Qikeng in June 2006 I gave a
talk on the analytic approach to the finite generation of the canonical ring
for a compact complex algebraic manifold of general type. This article is my
contribution to the proceedings of that conference from my talk. In this
article I give an overview of the analytic proof and focus on explaining how
the analytic method handles the problem of infinite number of interminable
blow-ups in the intuitive approach to prove the finite generation of the
canonical ring. The proceedings of the LU Qikeng conference will appear as
Issue No. 4 of Volume 51 of Science in China Series A: Mathematics
(www.springer.com/math/applications/journal/11425).


title: A Duality Exact Sequence for Legendrian Contact Homology

abstract:
  We establish a long exact sequence for Legendrian submanifolds L in P x R,
where P is an exact symplectic manifold, which admit a Hamiltonian isotopy that
displaces the projection of L off of itself. In this sequence, the singular
homology H_* maps to linearized contact cohomology CH^* which maps to
linearized contact homology CH_* which maps to singular homology. In
particular, the sequence implies a duality between the kernel of the map
(CH_*\to H_*) and the cokernel of the map (H_* \to CH^*). Furthermore, this
duality is compatible with Poincare duality in L in the following sense: the
Poincare dual of a singular class which is the image of a in CH_* maps to a
class \alpha in CH^* such that \alpha(a)=1.
  The exact sequence generalizes the duality for Legendrian knots in Euclidean
3-space [24] and leads to a refinement of the Arnold Conjecture for double
points of an exact Lagrangian admitting a Legendrian lift with linearizable
contact homology, first proved in [6].


title:
Hyperspherical Coulomb spheroidal representation in the Coulomb
  three-body problem

abstract:
  The new representation of the Coulomb three-body wave function via the
well-known solutions of the separable Coulomb two-centre problem
$\phi_j(\xi,\eta)=X_j(\xi)Y_j(\eta)$ is obtained, where $X_j(\xi)$ and
$Y_j(\eta)$ are the Coulomb spheroidal functions. Its distinguishing
characteristic is the coordination with the boundary conditions of the
scattering problem below the three-particle breakup. That is, the wave function
of the scattering particles in any open channel is the asymptotics of the
single, corresponding to that channel, term of the expansion suggested. The
effect is achieved due to the new relation between three internal coordinates
of the three-body system and the parameters of $\phi_j(\xi,\eta)$. It ensures
the orthogonality of $\phi_j(\xi,\eta)$ on the sphere of a constant
hyperradius, $\rho=const$, in place of the surface
$R=|\bi{x}_2-\bi{x}_1|=const$ appearing in the traditional Born-Oppenheimer
approach. The independent variables $\xi$ and $\eta$ are the orthogonal
coordinates on that sphere with three poles in the coalescence points. They are
connected with the elliptic coordinates on the plane by means of the
stereographic projection. For the total angular momentum $J\ge 0$ the products
of $\phi_j$ and the Wigner $D$-functions form the hyperspherical Coulomb
spheroidal (HSCS) basis on the five-dimensional hypersphere, $\rho$ being a
parameter. The system of the differential equations and the boundary conditions
for the radial functions $f^J_i(\rho)$, the coefficients of the HSCS
decomposition of the three-body wave function, are presented.


title:
Pseudogap Behavior Revealed in Interlayer Tunneling in Overdoped
  Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$

abstract:
  We report heating-compensated interlayer tunneling spectroscopy (ITS)
performed on stacks of overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ intrinsic
junctions, where most of bias-induced heating in the ITS was eliminated. The
onset temperature of the pseudogap (PG), revealed in the hump structure of the
electronic excitation spectra, reached nearly room temperature for our
overdoped intrinsic junctions, which represented the genuine PG onset. At a
temperature below but close to $T_c$, both the superconducting coherence peak
and the pseudogap hump coexisted, implying that the two gaps are of separate
origins. The hump voltage increased below $T_c$, following the superconducting
gap voltage, which led to a conclusion that the hump structure below $T_c$ in
our ITS arose from the combined contribution of the quasiparticle spectral
weights of two different characters; one of the superconducting state and
another of the PG state near the antinodal region.


title:
Band offset determination of the GaAs/GaAsN interface using the DFT
  method

abstract:
  The GaAs/GaAsN interface band offset is calculated from first principles. The
electrostatic potential at the core regions of the atoms is used to estimate
the interface potential and align the band structures obtained from respective
bulk calculations. First, it is shown that the present method performs well on
the well-known conventional/conventional AlAs/GaAs (001) superlattice system.
Then the method is applied to a more challenging nonconventional/conventional
GaAsN/GaAs (001) system, and consequently type I band lineup and valence-band
offset of about 35 meV is obtained for nitrogen concentration of about 3 %, in
agreement with the recent experiments. We also investigate the effect of strain
on the band lineup. For the GaAsN layer longitudinally strained to the GaAs
lattice constant, the type II lineup with a nearly vanishing band offset is
found, suggesting that the anisotropic strain along the interface is the
principal cause for the often observed type I lineup.


title: Stability of a processor sharing queue with varying throughput

abstract:
  In this paper, we present a stability criterion for Processor Sharing queues,
in which the throughput may depend on the number of customers in the system (in
such cases such as interferences between the users). Such a system is
represented by a point measure-valued stochastic recursion keeping track of the
remaining processing times of the customers.


title:
Upper Bound on Error Exponent of Regular LDPC Codes Transmitted over the
  BEC

abstract:
  The error performance of the ensemble of typical LDPC codes transmitted over
the binary erasure channel (BEC) is analyzed. In the past, lower bounds on the
error exponents were derived. In this paper a probabilistic upper bound on this
error exponent is derived. This bound holds with some confidence level.


title:
Young Stars in the Camelopardalis Dust and Molecular Clouds. I. The Cam
  OB1 Association

abstract:
  The distribution of dust and molecular clouds in the direction of Galactic
longitudes 132--158 deg and latitudes pm 12 deg is investigated. The maps of
dust distribution in the area were plotted from the following surveys: the star
counts in the DSS I database by Dobashi et al. (2005), the survey of the
average infrared color excesses by Froebrich et al. (2007) and the thermal dust
emission survey at 100 micrometers by Schlegel et al. (1998). The distribution
of molecular clouds was taken from the whole sky CO survey by Dame et al.
(2001). All these surveys show very similar cloud patterns in the area. Using
the radial velocities of CO, the distances to separate clouds are estimated. A
revised list of the Cam OB1 association members contains 43 stars and the open
cluster NGC 1502. 18 young irregular variable and H alpha emission stars are
identified in the area. All this proves that the star forming process in the
Camelopardalis clouds is still in progress.


title: Open string radiation from decaying FZZT branes

abstract:
  In this paper we continue studying the decay of unstable FZZT branes
initiated in [1],[2]. The mass of tachyonic mode in this model can be chosen
arbitrarily small and we use it as a perturbative parameter. In [2] a
time-dependent boundary conformal field theory (BCFT) describing the decay
process was studied and it was shown that in a certain sense this BCFT
interpolates between two stationary BCFT's corresponding to the UV and IR fixed
points of the associated RG flow. In the present work we find in the leading
order vertex operators of the time-dependent BCFT. We identify the "in" and
"out" vertex operators assigned to the UV and IR fixed points and compute the
related Bogolyubov coefficients. We show that there is a codimension one
subspace of the out-going states for which pair creation amplitudes are
independent of the initial wave function of the tachyonic mode. We demonstrate
that such amplitudes can be computed within the framework of first quantized
open string theory via suitably defined string two-point functions. We also
evaluate a three point function which we interpret as an amplitude for string
triplet creation due to interaction. Some peculiarities of scattering
amplitudes in the presence of tachyonic modes in the far past are discussed.


title:
Young Stars in the Camelopardalis Dust and Molecular Clouds. II.
  Infrared Objects

abstract:
  Using infrared photometric data extracted from the 2MASS, IRAS and MSX
databases, 142 suspected young stellar objects (YSOs) are selected from about 2
million stars in the Camelopardalis segment of the Milky Way limited by
Galactic longitude 132-158 deg, latitude pm 12 deg. According to radial
velocities of the associated CO clouds, the objects are attributed to three
molecular and dust cloud layers at 150--300 pc, 900 pc and 2.2 kpc distances
from the Sun. These objects concentrate into dust and molecular clouds and
exhibit extremely large reddenings (A_V up to 25 mag) which can be caused by
the dust in foreground clouds and circumstellar envelopes or disks. In the J-H
vs. H-K diagram these objects lie above the intrinsic line of T Tauri
variables, roughly along the black-body line. Among the identified objects,
some already known YSOs are present, including the well investigated massive
object GL 490. The spectral energy distributions between 700 nm and 100 mum
suggest that the objects may be YSOs of classes I, II and III. However, we do
not exclude the possibility that a small fraction of the objects, especially
those without IRAS and MSX photometry, may be unrecognized heavily reddened
OB-stars, late-type AGB stars or even galaxies.


title:
Tidal evolution of disky dwarf galaxies in the Milky Way potential: the
  formation of dwarf spheroidals

abstract:
  We conduct high-resolution collisionless N-body simulations to investigate
the tidal evolution of dwarf galaxies on an eccentric orbit in the Milky Way
(MW) potential. The dwarfs originally consist of a low surface brightness
stellar disk embedded in a cosmologically motivated dark matter halo. During 10
Gyr of dynamical evolution and after 5 pericentre passages the dwarfs suffer
substantial mass loss and their stellar component undergoes a major
morphological transformation from a disk to a bar and finally to a spheroid.
The bar is preserved for most of the time as the angular momentum is
transferred outside the galaxy. A dwarf spheroidal (dSph) galaxy is formed via
gradual shortening of the bar. This work thus provides a comprehensive
quantitative explanation of a potentially crucial morphological transformation
mechanism for dwarf galaxies that operates in groups as well as in clusters. We
compare three cases with different initial inclinations of the disk and find
that the evolution is fastest when the disk is coplanar with the orbit. Despite
the strong tidal perturbations and mass loss the dwarfs remain dark matter
dominated. For most of the time the 1D stellar velocity dispersion, \sigma,
follows the maximum circular velocity, V_{\rm max}, and they are both good
tracers of the bound mass. Specifically, we find that M_{\rm bound} \propto
V_{\rm max}^{3.5} and V_{\rm max} \sim \sqrt{3} \sigma in agreement with
earlier studies based on pure dark matter simulations. The latter relation is
based on directly measuring the stellar kinematics of the simulated dwarf and
may thus be reliably used to map the observed stellar velocity dispersions of
dSphs to halo circular velocities when addressing the missing satellites
problem.


title: Coupled quantum wires

abstract:
  We study a set of crossed 1D systems, which are coupled with each other via
tunnelling at the crossings. We begin with the simplest case with no
electron-electron interactions and find that besides the expected level
splitting, bound states can emerge. Next, we include an external potential and
electron-electron interactions, which are treated within the Hartree
approximation. Then, we write down a formal general solution to the problem,
giving additional details for the case of a symmetric external potential.
Concentrating on the case of a single crossing, we were able to explain recent
experinents on crossed metallic and semiconducting nanotubes [J. W. Janssen, S.
G. Lemay, L. P. Kouwenhoven, and C. Dekker, Phys. Rev. B 65, 115423 (2002)],
which showed the presence of localized states in the region of crossing.


title:
Young Stars in the Camelopardalis Dust and Molecular Clouds. III. the GL
  490 Region

abstract:
  Using the infrared photometry data extracted from the 2MASS, IRAS and MSX
databases, 50 suspected young stellar objects (YSOs) are selected from about
37500 infrared objects in the 3x3 deg area with the center at Galactic
longitude 142.5 deg and latitude +1.0 deg, in the vicinity of the young stellar
object GL 490 in the dark cloud DoH 942 (Dobashi et al. 2005). The spectral
energy distributions between 700 nm and 100 mum suggest that most of the
selected objects may be YSOs of classes I and II. In the color-magnitude
diagram K_s vs. H-K_s the suspected YSOs occupy an area right of the main
sequence what can be interpreted as being caused by the effects of luminosity,
interstellar and circumstellar reddening and infrared thermal emission in
circumstellar envelopes and disks.


title: A note on the black hole information paradox in de Sitter spacetimes

abstract:
  The possibility of stable or quasi--stable Planck mass black hole remnants as
solution to the black hole information paradox is commonly believed
phenomenologically unacceptable: since we have to expect a black hole remnant
for every possible initial state, the number of remnants should be infinite.
This would lead to remnant pair production in any physical process with a total
available energy roughly exceeding the Planck mass, against trivial evidences.
In this note I point out that the number of remnants in our Universe could be
finite, at least if the value of the cosmological constant is positive, as
present observational data could indicate. Nevertheless, it is not clear if a
huge but finite number of states is phenomenologically allowed.


title: Strong Gravitational Lensing by Schwarzschild Black Holes

abstract:
  The properties of the relativistic rings which show up in images of a source
when a black hole lies between the source and observer are examined. The impact
parameters are calculated, along with the distances of closest approach of the
rays which form a relativistic ring, their angular sizes, and their
"magnification" factors, which are much less than unity.


title:
An entropy preserving finite-element/finite-volume pressure correction
  scheme for the drift-flux model

abstract:
  We present in this paper a pressure correction scheme for the drift-flux
model combining finite element and finite volume discretizations, which is
shown to enjoy essential stability features of the continuous problem: the
scheme is conservative, the unknowns are kept within their physical bounds and,
in the homogeneous case (i.e. when the drift velocity vanishes), the discrete
entropy of the system decreases; in addition, when using for the drift velocity
a closure law which takes the form of a Darcy-like relation, the drift term
becomes dissipative. Finally, the present algorithm preserves a constant
pressure and a constant velocity through moving interfaces between phases. To
ensure the stability as well as to obtain this latter property, a key
ingredient is to couple the mass balance and the transport equation for the
dispersed phase in an original pressure correction step. The existence of a
solution to each step of the algorithm is proven; in particular, the existence
of a solution to the pressure correction step is derived as a consequence of a
more general existence result for discrete problems associated to the
drift-flux model. Numerical tests show a near-first-order convergence rate for
the scheme, both in time and space, and confirm its stability.


title: Nanomachining of mesoscopic graphite

abstract:
  An atomic force microscope is used to structure a film of multilayer
graphene. The resistance of the sample was measured in-situ during
nanomachining narrow trenches. We found a reversible behavior in the electrical
resistance which we attribute to the movement of dislocations. After several
attempts also permanent changes are observed.


title:
Triviality of a trace on the space of commuting trace-class self-adjoint
  operators

abstract:
  In the present article, we investigate a possibility of a real-valued map on
the space of tuples of commuting trace-class self-adjoint operators, which
behaves like the usual trace map on the space of trace-class linear operators.
It turns out that such maps are related with continuous group homomorphisms
from the Milnor's $K$-group of the real numbers into the additive group of real
numbers. Using this connection, it is shown that any such trace map must be
trivial.


title: Twisting the Baum-Connes morphism by a non-unitary representation

abstract:
  Let G be a locally compact group and rho a non-unitary finite dimensional
representation of G. We consider tensor products of rho by some unitary
representations of G in order to define two Banach algebras analogous to the
group C*-algebras, C*(G) and C*_r(G). We calculate the K-theory of such
algebras for a large class of groups satisfying the Baum-Connes conjecture.


title:
XMM-Newton observations of the Small Magellanic Cloud: XMMU
  J004814.1-731003, a 25.55 s Be/X-ray binary pulsar

abstract:
  To investigate candidates for Be/X-ray binaries in the Small Magellanic Cloud
(SMC), we observed a region around the emission nebula N19 with XMM-Newton in
October 2006. We analysed the EPIC data of the detected point sources to derive
their spectral and temporal characteristics. We detected X-ray pulsations with
a period of 25.550(2) s from the second-brightest source in the field, which we
designate XMMU J004814.1-731003. The X-ray spectrum is well modelled by a
highly absorbed (NH = 5x10^22) powerlaw with photon index 1.33+/-0.27. The
precise X-ray position allows us to identify a Be star as the optical
counterpart. XMMU J004814.1-731003 is located within the error circle of the
transient ASCA source AX J0048.2-7309, but its position is inconsistent with
that of the proposed optical counterpart of AX J0048.2-7309 (the emission line
star [MA93] 215). It remains unclear if XMMU J004814.1-731003 is associated
with AX J0048.2-7309. XMMU J004814.1-731003 might be identical to an RXTE
pulsar that was discovered with a period of 25.5 s, but which is listed as 51 s
pulsar in the recent literature.


title: Quantile Estimation of A general Single-Index Model

abstract:
  The single-index model is one of the most popular semiparametric models in
Econometrics. In this paper, we define a quantile regression single-index
model, which includes the single-index structure for conditional mean and for
conditional variance.


title:
Gluon scattering in N=4 super-Yang-Mills theory from weak to strong
  coupling

abstract:
  I describe some recent developments in the understanding of gluon scattering
amplitudes in N=4 super-Yang-Mills theory in the large-N_c limit. These
amplitudes can be computed to high orders in the weak coupling expansion, and
also now at strong coupling using the AdS/CFT correspondence. They hold the
promise of being solvable to all orders in the gauge coupling, with the help of
techniques based on integrability. They are intimately related to expectation
values for polygonal Wilson loops composed of light-like segments.


title:
Measurements of the gamma*p->Delta Reaction At Low Q^2: Probing the
  Mesonic Contribution

abstract:
  The determination of non-spherical angular momentum amplitudes in nucleons at
long ranges (low Q^{2}), was accomplished through the $p(\vec{e},e'p)\pi^0$
reaction in the Delta region at $Q^2=0.060$, 0.127, and 0.200 (GeV/c)^2 at the
Mainz Microtron (MAMI) with an accuracy of 3%. The results for the dominant
transition magnetic dipole amplitude and the quadrupole to dipole ratios have
been obtained with an estimated model uncertainty which is approximately the
same as the experimental uncertainty. Lattice and effective field theory
predictions agree with our data within the relatively large estimated
theoretical uncertainties. Phenomenological models are in good agreement with
experiment when the resonant amplitudes are adjusted to the data. To check
reaction model calculations additional data were taken for center of mass
energies below resonance and for the $\sigma_{TL'}$ structure function. These
results confirm the dominance, and general Q^2 variation, of the pionic
contribution at large distances.


title: Joint differential resolvents for pseudopolynomials

abstract:
  The existence of linear differential resolvents for z^alpha for any root z of
an ordinary polynomial with coefficients in a given ordinary differential field
has been established, where alpha is an indeterminate constant with respect to
the derivation of the given field. In this paper we consider several alphas. We
will call a finite sum of indeterminate powers of a variable v a
pseudopolynomial in v. We will generalize the definition of a differential
resolvent of a single polynomial for a single monomial z^alpha to the
definition of a differential resolvent of several polynomials for a
pseudopolynomial in the roots. We will also generalize the definition of a
resolvent to have non-consecutive derivatives. We will show that the authors
powersum formula may be used to compute this more general differential
resolvent.


title: KM3NeT:a large underwater neutrino telescope in the Mediterranean Sea

abstract:
  High energy neutrinos produced in astrophysical processes will allow for a
new way of studying the universe. In order to detect the expected flux of high
energy neutrinos from specific astrophysical sources, neutrino telescopes of a
scale of a km^3 of water will be needed. A Northern Hemisphere detector is
being proposed to be sited in a deep area of the Mediterranean Sea. This
detector will provide complimentary sky coverage to the IceCube detector being
built at the South Pole. The three neutrino telescope projects in the
Mediterranean (ANTARES, NEMO and NESTOR) are partners in an effort to design,
and build such a km^3 size neutrino telescope, the KM3NeT. The EU is funding a
3-year Design Study; the status of the Design Study is presented and some
technical issues are discussed.


title: A Kobayashi metric version of Bun Wong's theorem

abstract:
  We prove that a strongly pseudoconvex domain with noncompact group of
Kobayashi/Royden metric isometries must be biholomorphic to the unit ball.


title: Uniqueness Results for Nonlocal Hamilton-Jacobi Equations

abstract:
  We are interested in nonlocal Eikonal Equations describing the evolution of
interfaces moving with a nonlocal, non monotone velocity. For these equations,
only the existence of global-in-time weak solutions is available in some
particular cases. In this paper, we propose a new approach for proving
uniqueness of the solution when the front is expanding. This approach
simplifies and extends existing results for dislocation dynamics. It also
provides the first uniqueness result for a Fitzhugh-Nagumo system. The key
ingredients are some new perimeter estimates for the evolving fronts as well as
some uniform interior cone property for these fronts.


title: Jet evolution in the N=4 SYM plasma at strong coupling

abstract:
  Within the framework of the AdS/CFT correspondence, we study the time
evolution of an energetic R-current propagating through a finite temperature,
strongly coupled, N=4 SYM plasma and propose a physical picture for our
results. In this picture, the current splits into a pair of massless partons,
which then evolve via successive branchings, in such a way that energy is
quasi-democratically divided among the products of a branching. We point out a
duality between the transverse size of the partonic system produced through
branching and the radial distance traveled by the dual Maxwell wave in the AdS
geometry. For a time-like current, the branching occurs already in the vacuum,
where it gives rise to a system of low-momentum partons isotropically
distributed in the transverse plane. But at finite temperature, the branching
mechanism is modified by the medium, in that the rate for parton splitting is
enhanced by the transfer of transverse momentum from the partons to the plasma.
This mechanism, which controls the parton energy loss, is sensitive to the
energy density in the plasma, but not to the details of the thermal state. We
compute the lifetime of the current for various kinematical regimes and provide
physical interpretations for other, related, quantities, so like the meson
screening length, the drag force, or the trailing string, that were previously
computed via AdS/CFT techniques.


title: Current star formation in early-type galaxies and the K+A phenomenon

abstract:
  We present the results of an effort to identify and study a sample of the
likely progenitors of elliptical (E) and lenticular (S0) K+A galaxies. To
achieve this, we have searched a sample ~11,000 nearby (m(r)<16) early-type
galaxies selected by morphology from the Sloan Digital Sky Survey (SDSS) Main
spectroscopic sample for actively star-forming E and S0 galaxies. Using
emission line ratios and visual inspection of SDSS g-band images, we have
identified 335 galaxies from the SDSS Fourth Data Release (DR4) as actively
star-forming E and S0 galaxies. These galaxies make up about 3% of the total
early-type sample and less than 1% of all Main galaxies with m(r)<16. We also
identified a sample of ~400 K+A galaxies from DR4 with m(r)<16; more than half
of these are E and S0 galaxies. We find that star-forming early-type galaxies
and K+A galaxies have similar mass distributions; they are on average less
massive than typical early-type galaxies but more massive than the average
star-forming galaxy. Both of these types of galaxies are found in higher
fractions among all galaxies in lower density environments. The fractions of
star-forming E and S0 galaxies and E and S0 K+A galaxies depend on environment
in nearly the same way. Model spectra fit to the stellar continua of the
star-forming E and S0 galaxies showed that their properties are consistent with
star formation episodes of <1 Gyr in duration. The modelling results imply that
on average, the star formation episodes will increase the stellar masses by
about 4%. There is also evidence that the star-forming regions within these
galaxies are rotationally supported.


title: Value distribution of cyclotomic polynomial coefficients

abstract:
  Let a_n(k) be the kth coefficient of the nth cyclotomic polynomial Phi_n(x).
As n ranges over the integers, a_n(k) assumes only finitely many values. For
any such value v we determine the density of integers n such that a_n(k)=v.
Also we study the average of the a_n(k). We derive analogous results for the
kth Taylor coefficient of 1/Phi_n(x) (taken around x=0), the kth coefficient of
the nth reciprocal cyclotomic polynomial. We formulate various open problems.


title:
Problems on automorphism groups of nonpositively curved polyhedral
  complexes and their lattices

abstract:
  The goal of this paper is to present a number of problems about automorphism
groups of nonpositively curved polyhedral complexes and their lattices, meant
to highlight possible directions for future research.


title: Single-file dynamics with different diffusion constants

abstract:
  We investigate the single-file dynamics of a tagged particle in a system
consisting of N hardcore interacting particles (the particles cannot pass each
other) which are diffusing in a one-dimensional system where the particles have
different diffusion constants. For the two particle case an exact result for
the conditional probability density function (PDF) is obtained for arbitrary
initial particle positions and all times. The two-particle PDF is used to
obtain the tagged particle PDF. For the general N-particle case (N large) we
perform stochastic simulations using our new computationally efficient
stochastic simulation technique based on the Gillespie algorithm. We find that
the mean square displacement for a tagged particle scales as the square root of
time (as for identical particles) for long times, with a prefactor which
depends on the diffusion constants for the particles; these results are in
excellent agreement with very recent analytic predictions in the mathematics
literature.


title:
On the least squares estimator in a nearly unstable sequence of
  stationary spatial AR models

abstract:
  A nearly unstable sequence of stationary spatial autoregressive processes is
investigated, when the sum of the absolute values of the autoregressive
coefficients tends to one. It is shown that after an appropriate norming the
least squares estimator for these coefficients has a normal limit distribution.
If none of the parameters equals zero than the typical rate of convergence is
n.


title: Instability of Hopf vector fields on Lorentzian Berger spheres

abstract:
  In this work, we study the stability of Hopf vector fields on Lorentzian
Berger spheres as critical points of the energy, the volume and the generalized
energy. In order to do so, we construct a family of vector fields using the
simultaneous eigenfunctions of the Laplacian and of the vertical Laplacian of
the sphere. The Hessians of the functionals are negative when they act on these
particular vector fields and then Hopf vector fields are unstable. Moreover, we
use this technique to study some of the open problems in the Riemannian case.


title:
BCS-BEC Crossover of a Quasi-two-dimensional Fermi Gas: the Significance
  of Dressed Molecules

abstract:
  We study the crossover of a quasi-two-dimensional Fermi gas trapped in the
radial plane from the Bardeen-Cooper-Schrieffer (BCS) regime to the
Bose-Einstein condensation (BEC) regime by crossing a wide Feshbach resonance.
We consider two effective two-dimensional Hamiltonians within the mean-field
level, and calculate the zero-temperature cloud size and number density
distribution. For a model 1 Hamiltonian with renormalized atom-atom
interaction, we observe a constant cloud size for arbitrary detunings. For a
model 2 Hamiltonian with renormalized interactions between atoms and dressed
molecules, the cloud size deceases from the BCS to BEC side, which is
consistent with the picture of BCS-BEC crossover. This qualitative discrepancy
between the two models indicates that the inclusion of dressed molecules is
essential for a mean-field description of quasi-two-dimensional Fermi systems,
especially on the BEC side of the Feshbach resonance.


title: Trimming Down the Willman 1 dSph

abstract:
  Willman 1 is a small low surface-brightness object identified in the Sloan
Digital Sky Survey and tentatively classified as a very low luminosity dSph
galaxy. Further study has supported this classification while hinting that it
may be undergoing disruption by the Milky Way potential. In an effort to better
constrain the nature of Willman 1, we present a comprehensive analysis of the
brightest stars in a 0.6 square degree field centered on the overdensity.
High-resolution HET spectra of two previously identified Willman 1 RGB stars
show that one is a metal-rich foreground dwarf while the other is a metal-poor
giant. The one RGB star that we confirm as a member of Willman 1 has a low
metallicity ([Fe/H]=-2.2) and a surprisingly low alpha-element abundance
([alpha/Fe]=-0.11). Washington+DDO51 photometry indicates that 2-5 of the seven
brightest Willman 1 stars identified in previous studies are actually dwarf
stars, including some of the more metal-rich stars that have been used to argue
both for an abundance spread and a more metal-rich stellar population than
galaxies of similar luminosity. The remaining stars are too blue or too faint
for photometric classification. The Washington+DDO51 photometry identifies
three potential RGB stars in the field but HET spectra show that they are
background halo stars. Time series photometry identifies one apparent variable
star in the field, but it is unlikely to be associated with Willman 1. Our
wide-field survey indicates that over 0.6 square degrees, Willman 1 does not
have a single RR Lyrae star, a single BHB star or a single RGB star beyond its
tidal radius. While our results confirm that Willman 1 is most likely a
low-luminosity metal-poor dSph galaxy, the possibility remains that it is a
tidally disrupted metal-poor globular cluster.


title: Perturbation Growth in Anisotropic Cosmologies

abstract:
  We study the growth of perturbations in an expanding Bianchi type-I metric
that evolves according to an energy density that includes dust and a
cosmological constant. Assuming an epoch where the cosmological constant is
subdominant, we find that, for a reasonably large set of initial conditions,
the metric fluctuations grow fast enough to make the metric inhomogeneous
before the cosmological constant becomes the dominant form of energy. We have
examined values for the cosmological constant that are in the interval $10^{10}
{GeV}$ to $10^{16} {GeV}$.


title:
Superconductivity in $\beta$-pyrochlore superconductor KOs$_{2}$O$_{6}$:
  treatment within strong-coupling Eliashberg theory

abstract:
  We study the influence of the rattling phonons on superconductivity in
$\beta$-pyrochlore KOs$_{2}$O$_{6}$ compound based on the strong-coupling
Eliashberg approach. In particular, analyzing the specific heat data we find
that the rattling phonon frequency changes discontinuously at the critical
temperature of the first order phase transition. Solving the strong-coupling
Eliashberg equations with temperature dependent $\alpha^{2}F(\omega)$, we
investigate the consequence of this first order phase transition for the
anomalous temperature dependence of the superconducting gap. We discuss our
results in context of the recent experimental data.


title: Impact cratering and the Oort cloud

abstract:
  We calculate the expected flux profile of comets into the planetary system
from the Oort cloud arising from Galactic tides and encounters with molecular
clouds. We find that both periodic and sporadic bombardment episodes, with
amplitudes an order of magnitude above background, occur on characteristic
timescales ~25-35 Myr.
  Bombardment episodes occurring preferentially during spiral arm crossings may
be responsible both for mass extinctions of life and the transfer of viable
microorganisms from the bombarded Earth into the disturbing nebulae. Good
agreement is found between the theoretical expectations and the age
distribution of large, well-dated terrestrial impact craters of the past 250
million years.
  A weak periodicity of ~36 Myr in the cratering record is consistent with the
Sun's recent passage through the Galactic plane, and implies a central plane
density ~0.15 M_Sun pc^(-3). This leaves little room for a significant dark
matter component in the disc.


title:
Vortex dynamics in rotating counterflow and plane Couette and Poiseuille
  turbulence in superfluid Helium

abstract:
  An equation previously proposed to describe the evolution of vortex line
density in rotating counterflow turbulent tangles in superfluid helium is
generalized to incorporate nonvanishing barycentric velocity and velocity
gradients. Our generalization is compared with an analogous approach proposed
by Lipniacki, and with experimental results by Swanson et al. in rotating
counterflow, and it is used to evaluate the vortex density in plane Couette and
Poiseuille flows of superfluid helium.


title:
Secondary protons from ultra high energy cosmic ray nuclei: is the
  Greisen-Zatsepin-Kuzmin cutoff unavoidable?

abstract:
  We discuss the production of ultra high energy secondary protons by cosmic
ray primary nuclei propagating in the intergalactic space through Cosmic
Microwave Background (CMB) and Infrared (IR) radiations. Under the assumption
that only primary nuclei with a fixed atomic mass number $A_0$ are accelerated,
the spectrum of secondary protons is calculated. It is found that for all $A_0$
the diffuse flux of secondary protons starts to dominate over that of primary
nuclei at energy $E \sim (1 - 2)\times 10^{19}$ eV, and thus the standard
Greisen-Zatsepin -Kuzmin (GZK) cutoff is produced.


title:
Adversarial Scheduling Analysis of Game Theoretic Models of Norm
  Diffusion

abstract:
  In (Istrate, Marathe, Ravi SODA 2001) we advocated the investigation of
robustness of results in the theory of learning in games under adversarial
scheduling models. We provide evidence that such an analysis is feasible and
can lead to nontrivial results by investigating, in an adversarial scheduling
setting, Peyton Young's model of diffusion of norms. In particular, our main
result incorporates into Peyton Young's model.


title: The Dirac Equation in Kerr-Newman-AdS Black Hole Background

abstract:
  We consider the Dirac equation on the Kerr-Newman-AdS black hole background.
We first perform the variable separation for the Dirac equation and define the
Hamiltonian operator $\hat H$. Then we show that for a massive Dirac field with
mass $\mu\geq \frac{1}{2l}$ essential selfadjointness of $\hat H$ on
$C_0^{\infty} ((r_+,\infty) \times S^2)^4$ is obtained even in presence of the
boundary-like behavior of infinity in an asymptotically AdS black hole
background. Furthermore qualitative spectral properties of the Hamiltonian are
taken into account and in agreement with the existing results concerning the
case of stationary axi-symmetric asymptotically flat black holes we infer the
absence of time-periodic and normalizable solutions of the Dirac equation
around the black hole in the non-extremal case.


title:
Quantum Scent Dynamics (QSD): A new composite model of physical
  particles

abstract:
  The paper introduces an alternative rishon model for a composite structure of
quarks and leptons. The model builds matter from six basic blocks (and their
antiparticles). For this reason it introduces new properties of rishons, called
"scents", that can take two values, called masculine and feminine scents, which
can appear in three colours both. The Quantum Scent Dynamics (QSD) model
calculates new electric charges for the rishons. Then it discusses the
construction of the known families of particles from scents, as well as the
constraints and advantages of the proposed hypothetic model.


title: FILOU oscillation code

abstract:
  The present paper provides a description of the oscillation code FILOU, its
main features, type of applications it can be used for, and some representative
solutions. The code is actively involved in CoRoT/ESTA exercises (this volume)
for the preparation for the proper interpretation of space data from the CoRoT
mission. Although CoRoT/ESTA exercises have been limited to the oscillations
computations for non-rotating models, the main characteristic of FILOU is,
however, the computation of radial and non-radial oscillation frequencies in
presence of rotation. In particular, FILOU calculates (in a perturbative
approach) adiabatic oscillation frequencies corrected for the effects of
rotation (up to the second order in the rotation rate) including near
degeneracy effects. Furthermore, FILOU works with either a uniform rotation or
a radial differential rotation profile (shellular rotation), feature which
makes the code singular in the field.


title:
The influence of spin-dependent phases of tunneling electrons on the
  conductance of a point ferromagnet/isolator/superconductor contact

abstract:
  The Andreev reflection probability for a ferromagnet/isolator/superconductor
(FIS) contact at the arbitrary spin-dependent amplitudes of the electron waves
transmitted through and reflected from the potential barrier is found. It is
shown that Andreev reflection probabilities of electron and hole excitations in
the FIS contact are different. The energy levels of Andreev bound states are
found. The ballistic conductance of the point FIS contact is calculated.


title: A Singularity Problem with f(R) Dark Energy

abstract:
  In this paper, I point out that there is a curvature singularity problem
appearing on non-linear level that generally plagues f(R) models that modify
Einstein gravity in the infrared. It is caused by the fact that for the
effective scalar degree of freedom, the curvature singularity is at a finite
field value and energy level, and can be easily accessed by the field dynamics
in the presence of matter. This problem is invisible in linearized analysis,
except for the tell-tale growing oscillatory modes it causes. In view of this,
viability of many f(R) models in current literature will have to be
re-evaluated.


title: A Ruelle Operator for continuous time Markov Chains

abstract:
  We consider a generalization of the Ruelle theorem for the case of continuous
time problems. We present a result which we believe is important for future use
in problems in Mathematical Physics related to $C^*$-Algebras We consider a
finite state set $S$ and a stationary continuous time Markov Chain $X_t$,
$t\geq 0$, taking values on S. We denote by $\Omega$ the set of paths $w$
taking values on S (the elements $w$ are locally constant with left and right
limits and are also right continuous on $t$). We consider an infinitesimal
generator $L$ and a stationary vector $p_0$. We denote by $P$ the associated
probability on ($\Omega, {\cal B}$). This is the a priori probability. All
functions $f$ we consider bellow are in the set ${\cal L}^\infty (P)$. From the
probability $P$ we define a Ruelle operator ${\cal L}^t, t\geq 0$, acting on
functions $f:\Omega \to \mathbb{R}$ of ${\cal L}^\infty (P)$. Given $V:\Omega
\to \mathbb{R}$, such that is constant in sets of the form $\{X_0=c\}$, we
define a modified Ruelle operator $\tilde{{\cal L}}_V^t, t\geq 0$. We are able
to show the existence of an eigenfunction $u$ and an eigen-probability $\nu_V$
on $\Omega$ associated to $\tilde{{\cal L}}^t_V, t\geq 0$. We also show the
following property for the probability $\nu_V$: for any integrable $g\in {\cal
L}^\infty (P)$ and any real and positive $t$ $$ \int e^{-\int_0^t (V \circ
\Theta_s)(.) ds} [ (\tilde{{\cal L}}^t_V (g)) \circ \theta_t ] d \nu_V = \int g
d \nu_V$$ This equation generalize, for the continuous time Markov Chain, a
similar one for discrete time systems (and which is quite important for
understanding the KMS states of certain $C^*$-algebras).


title: Semiclassical Asymptotics on Manifolds with Boundary

abstract:
  We discuss semiclassical asymptotics for the eigenvalues of the Witten
Laplacian for compact manifolds with boundary in the presence of a general
Riemannian metric. To this end, we modify and use the variational method
suggested by Kordyukov, Mathai and Shubin (2005), with a more extended use of
quadratic forms instead of the operators. We also utilize some important ideas
and technical elements from Helffer and Nier (2006), who were the first to
supply a complete proof of the full semi-classical asymptotic expansions for
the eigenvalues with fixed numbers.


title: Odd Tachyons in Compact Extra Dimensions

abstract:
  We consider a real scalar field with an arbitrary negative bulk mass term in
a general 5D setup, where the extra spatial coordinate is a warped interval of
size $\pi R$. When the 5D field verifies Neumann conditions at the boundaries
of the interval, the setup will always contain at least one tachyonic KK mode.
On the other hand, when the 5D scalar verifies Dirichlet conditions, there is
always a critical (negative) mass $M_{c}^2$ such that the Dirichlet scalar is
stable as long as its (negative) bulk mass $\mu^2$ verifies $M^2_{c}<\mu^2$.
Also, if we fix the bulk mass $\mu^2$ to a sufficiently negative value, there
will always be a critical interval distance $\pi R_c$ such that the setup is
unstable for $R>R_c$. We point out that the best mass (or distance) bound is
obtained for the Dirichlet BC case, which can be interpreted as the
generalization of the Breitenlohner-Freedman (BF) bound applied to a general
compact 5D warped spacetime. In particular, in a slice of $AdS_5$ the critical
mass is $M^2_{c}=-4k^2 -1/R^2$ and the critical interval distance is given by
$1/R_c^2=|\mu^2|-4k^2$, where $k$ is the $AdS_5$ curvature (the 5D flat case
can be obtained in the limit $k\to 0$, whereas the infinite $AdS_5$ result is
recovered in the limit $R\to \infty$).


title: On the geometry of SL(2)-equivariant flips

abstract:
  In this paper, we show that any 3-dimensional normal affine quasihomogeneous
SL(2)-variety can be described as a categorical quotient of a 4-dimensional
affine hypersurface. Moreover, we show that the Cox ring of an arbitrary
3-dimensional normal affine quasihomogeneous SL(2)-variety has a unique
defining equation. This allows us to construct SL(2)-equivariant flips by
different GIT-quotients of hypersurfaces. Using the theory of spherical
varieties, we describe SL(2)-flips by means of 2-dimensional colored cones.


title: Grids of stellar evolution models for asteroseismology (CESAM + POSC)

abstract:
  In this paper we present a grid of stellar evolution models, computed with an
up-to-date physical description of the internal structure, using the Code
d'Evolution Stellaire Adaptatif et Modulaire (CESAM). The evolutionary
sequences span from the pre-main sequence to the beginning of the Red Giant
Branch and cover an interval of mass typical for low and intermediate mass
stars. The chemical composition (both helium and metal abundance) is the solar
one. The frequencies of oscillation, computed for specific stellar models of
the grid using the Porto Oscillations Code (POSC), are also provided.
  This work was accomplished in order to support the preparation of the CoRoT
mission within the Evolution and Seismic Tools Activity (CoRoT/ESTA). On the
other hand, the grid can also be used, more generally, to interpret the
observational properties of either individual stars or stellar populations. The
grids (data and documentation) can be found at
http://www.astro.up.pt/corot/models/cesam


title: All cyclic p-roots of index 3, found by symmetry-preserving calculations

abstract:
  When using a Groebner basis to solve the highly symmetric system of algebraic
equations defining the cyclic p-roots, one has the feeling that much of the
advantage of computerized symbolic algebra over hand calculation is lost
through the fact that the symmetry is immediately ``thrown out'' by the
calculations. In this paper, the problem of finding (for all relevant primes p)
all cyclic p-roots of index 3 is treated with the symmetry preserved through
the calculations. Once we had found the relevant formulas, using MAPLE and
MATHEMATICA, the calculations could even be made by hand. On the other hand,
with respect to a straightforward attack with Groebner basis, it is not even
clear how this could be organized for a general p.
  In other terminologies, our results involve listings of all bi-unimodular
sequences constant on the cosets of the group G_0 of cubic residues, or
equivalently all circulant complex Hadamard matrices related to G_0.
  The corresponding problem for bi-unimodular sequences of index 2 was solved
by the first named author in 1989 and shortly after solved independently by de
la Harpe and Jones in the case p = 1 (mod 4) and by Munemasa and Watatani in
the case p = 3 (mod 4).


title: Quantum Cryptography

abstract: There is no abstract for this review article.


title: On Anisotropic Dark Energy

abstract:
  Since the discovery of the accelerated expansion of the universe, it was
necessary to introduce a new component of matter distribution called dark
energy. The standard cosmological model considers isotropy of the pressure and
assumes an equation of state $p=\omega \rho$, relating the pressure $p$ and the
energy density $\rho$. The interval of the parameter $\omega$ defines the kind
of matter of the universe, related to the fulfillment, or not, of the energy
conditions of the fluid. The recent interest in this kind of fluid with
anisotropic pressure, in the scenario of the gravitational collapse and star
formation, imposes a carefull analysis of the energy conditions and the role of
the components of the pressure. Here, in this work, we show an example where
the classification of dark energy for isotropic pressure fluids is used
incorrectly for anisotropic fluids. The correct classification and its
consequences are presented.


title: Twisted coronal loops in uniform gravity

abstract:
  Coronal loop emission profiles are often of remarkably constant width along
their entire lengths, contradicting expectations based on model coronal
magnetic field strengths decreasing with height. Meanwhile Paul Bellan has
produced a theoretical model in which an initially empty, twisted force-free
loop, on being filled with plasma via upflow at each foot point, in the absence
of significant gravitational effects, forms a narrow, filamentary loop of
constant cross-section. In this paper, we focus on equilibrium states that
include stratification by uniform gravity while retaining the effects of
magnetic field twist. Comparing these with related force-free equilibria, it is
found that injection of low-$\beta $ plasma under coronal conditions is not
likely to change the shape of a loop significantly. These linear equilibria
apply to the interiors and boundaries of loops only, with external influences
modeled by boundary total pressures. The effects of total pressure balance with
surroundings and of gravitational stratification are to inhibit the pinching of
a loop to a constant cross-section. Only if the plasma $\beta$ were high enough
for the plasma to reconfigure the external field and the hydrostatic scale
height much greater than the loop size could the final state have nearly
constant cross section. We do not expect this to occur in the corona.


title:
The Web of Connections between Tourism Companies in Elba: Structure and
  Dynamics

abstract:
  Tourism destination networks are amongst the most complex dynamical systems,
involving a myriad of human-made and natural resources. In this work we report
a complex network-based systematic analysis of the Elba (Italy) tourism
destination network, including the characterization of its structure in terms
of a set of several traditional measurements, the investigation of its
modularity, as well as its comprehensive study in terms of the recently
reported superedges approach. In particular, structural (the number of paths of
distinct lengths between pairs of nodes, as well as the number of reachable
companies) and dynamical features (transition probabilities and the
inward/outward activations and accessibilities) are measured and analyzed,
leading to a series of important findings related to the interactions between
tourism companies. Among the several reported results, it is shown that the
type and size of the companies influence strongly their respective activations
and accessibilities, while their geographical position does not seem to matter.
It is also shown that the Elba tourism network is largely fragmented and
heterogeneous, so that it could benefit from increased integration.


title: Turbulence measurements from HI absorption spectra

abstract:
  We use the millennium Arecibo 21 cm absorption-line survey measurements to
examine the issue of the non-thermal contribution to the observed Galactic HI
line widths. If we assume a simple, constant pressure model for the HI in the
Galaxy, we find that the non-thermal contribution to the line width, v_{nt}
scales as v^2_{nt} \propto l^{\alpha}, for v_{nt} larger than \sim 0.7 km
s^{-1}. Here l is a derived length scale and \alpha \sim 0.7 \pm 0.1. This is
consistent with what one would expect from a turbulent medium with a Kolmogorov
scaling. Such a scaling is also predicted by theoretical models and numerical
simulations of turbulence in a magnetized medium. For non-thermal line widths
narrower than \sim 0.7 km s^{-1}, this scaling breaks down, and we find that
the likely reason is ambiguities arising from Gaussian decomposition of
intrinsically narrow, blended lines. We use the above estimate of the
non-thermal contribution to the line width to determine corrected HI kinetic
temperature. The new limits that we obtain imply that a significantly smaller
(\sim 40% as opposed to 60%) fraction of the atomic interstellar medium in our
Galaxy is in the warm neutral medium phase.


title: Stellar age versus mass of early-type galaxies in the Virgo Cluster

abstract:
  The flux excess of elliptical galaxies in the far-ultraviolet can be
reproduced by population synthesis models when accounting for the population of
old hot helium-burning subdwarf stars. This has been achieved by Han and
coworkers through a quantitative model of binary stellar evolution. Here, we
compare the resulting evolutionary population synthesis model to the GALEX
far-near ultraviolet colors (FUV-NUV) of Virgo cluster early-type galaxies that
were published by Boselli and coworkers. FUV-NUV is reddest at about the
dividing luminosity of dwarf and giant galaxies, and becomes increasingly blue
for both brighter and fainter luminosities. This behavior can be easily
explained by the binary model with a continuous sequence of longer duration and
later truncation of star formation at lower galaxy masses. Thus, in contrast to
previous conclusions, the GALEX data do not require a dichotomy between the
stellar population properties of dwarfs and giants. Their apparently opposite
behavior in FUV-NUV occurs naturally when the formation of hot subdwarfs
through binary evolution is taken into account.


title: (Non-)BPS bound states and D-brane instantons

abstract:
  We study non-perturbative effects in four-dimensional N=1 supersymmetric
orientifold compactifications due to D-brane instantons which are generically
not invariant under the orientifold projection. We show that they can yield
superpotential contributions via a multi-instanton process at threshold. Some
constituents of this configuration form bound states away from the wall of
marginal stability which can decay in other regions of moduli space. A
microscopic analysis reveals how contributions to the superpotential are
possible when new BPS states compensate for their decay. We study this
concretely for D2-brane instantons along decaying special Lagrangians in Type
IIA and for D5-branes instantons carrying holomorphic bundles in Type I theory.


title: Stringy Instantons in IIB Brane Systems

abstract:
  In this note, we study D-brane instantons which intersect N=1 supersymmetric
configurations of space-filling D-branes in general Calabi-Yau
compactifications of type IIB string theory. Our focus is on rigid ``stringy
instantons'' -- those which cannot be interpreted as Yang-Mills instantons in a
non-Abelian gauge group on any stack of space-filling D-branes. We show that
their contributions to the space-time superpotential can be determined by a
topological B-model computation of the tree-level superpotential for a related
auxiliary brane system. This computation is very tractable, as it is governed
by an A-infinity structure. We summarize the stringy instanton contribution to
the space-time superpotential in a simple formula.


title: Superconductor-to-normal transition in finite nanowires

abstract:
  In this paper we discuss the interplay of quantum fluctuations and
dissipation in uniform superconducting nanowires. We consider a
phenomenological model with superconducting and normal components, and a finite
equilibration rate between these two-fluids. We find that phase-slip dipoles
proliferate in the wire, and decouple the two-fluids within its bulk. This
implies that the the normal fluid only couples to the superconductor fluid
through the leads at the edges of the wire, and the {\it local} dissipation is
unimportant. Therefore, while long wires have a superconductor-metal transition
tuned by local properties of the superconducting fluid, short wires have a
transition when the {\it total} resistance is $R_{total}=R_Q=h/4e^2$.


title:
XMM-Newton observations of the Narrow-Line Seyfert 1 galaxy Mrk 335 in
  an historical low X-ray flux state

abstract:
  We report the discovery of strong soft X-ray emission lines and a hard
continuum above 2 keV in the Narrow-Line Seyfert 1 galaxy Mrk 335 during an
extremely low X-ray flux state. Mrk 335 was observed for 22 ks by XMM-Newton in
July 2007 as a Target of Opportunity to examine it in its X-ray low-flux state,
which was discovered with Swift. Long-term light curves suggest that this is
the lowest flux state this AGN has ever been seen in. However, Mrk 335 is still
sufficiently bright that its X-ray properties can be studied in detail. The
X-ray continuum spectrum is very complex and requires several components to
model. Statistically, partial covering and blurred reflection models work well.
We confirm the presence of a strong narrow Fe line at 6.4 keV. High-resolution
spectroscopy with the XMM-RGS reveals strong, soft X-ray emission lines not
detected in previous, higher signal-to-noise, XMM-Newton observations, such as:
highly ionized Fe lines, O VII, Ne IX and Mg XI lines. The optical/UV fluxes
are similar to those previously measured with Swift. Optical spectroscopy taken
in 2007 September do not show any changes to optical spectra obtained 8 years
earlier.


title:
Radio frequency spectroscopy of a strongly imbalanced Feshbach-resonant
  Fermi gas

abstract:
  A sufficiently large species imbalance (polarization) in a two-component
Feshbach resonant Fermi gas is known to drive the system into its normal state.
We show that the resulting strongly-interacting state is a conventional Fermi
liquid, that is, however, strongly renormalized by pairing fluctuations. Using
a controlled 1/N expansion, we calculate the properties of this state with a
particular emphasis on the atomic spectral function, the momentum distribution
functions displaying the Migdal discontinuity, and the radio frequency (RF)
spectrum. We discuss the latter in the light of the recent experiments of
Schunck et al. (cond-mat/0702066) on such a resonant Fermi gas, and show that
the observations are consistent with a conventional, but strongly renormalized
Fermi-liquid picture.


title: Kerr-Taub-NUT Spacetime with Maxwell and Dilaton Fields

abstract:
  We present an exact solution describing a stationary and axisymmetric object
with electromagnetic and dilaton fields. The solution generalizes the usual
Kerr-Taub-NUT (Newman-Unti-Tamburino) spacetime in general relativity and is
obtained by boosting this spacetime in the fifth dimension and performing a
Kaluza-Klein reduction to four dimensions. We also discuss the physical
parameters of this solution and calculate its gyromagnetic ratio.


title:
Deep optical spectroscopy of extended Lyman alpha emission around three
  radio-quiet z=4.5 quasars

abstract:
  We report the first results of a spectroscopic search for Lyman alpha,
envelopes around three z=4.5 radio-quiet quasars. Our observational strategy
uses the FORS2 spectrograph attached to the UT1 of the Very Large Telescope
(VLT) in the multi-slit mode. This allows us to observe simultaneously the
quasars and several PSF stars. The spectra of the latter are used to remove the
point-like quasar from the data, and to unveil the faint underlying Lyman
alpha, envelopes associated with the quasars with unprecedented depth. We
clearly detect an envelope around two of the three quasars. These envelopes
measure respectively 10" and 13" in extent (i.e. 67 kpc and 87 kpc). This is 5
to 10 times larger than predicted by the models of Haiman & Rees (2001) and up
to 100 times fainter. Our observations better agree with models involing a
clumpy envelope as in Alam & Miralda-Escude (2002) or Chelouche et al. (2008).
We find that the brighter quasars also have the brighter envelopes but that the
extend of the envelopes does not depend on the quasar luminosity. Although our
results are based on only two objects with a detected Lyman alpha, envelope,
the quality of the spatial deblending of the spectra lends considerable hope to
estimate the luminosity function and surface brightness profiles of high
redshift Lyman alpha, envelopes down to F= 2-3 10^{-21} erg/s/cm^2/A. We find
that the best strategy to carry out such a project is to obtain both
narrow-band images and deep slit-spectra.


title:
The Seyfert 1 Galaxy Mrk 335 at a very low flux state: mapping the soft
  X-ray photoionised gas

abstract:
  This paper reports on an XMM-Newton observation of the Seyfert 1 Galaxy Mrk
335 performed as a Target of Opportunity when the source was in an unusually
low flux state. The low level of continuum emission unveiled an underlying
line-rich soft X-ray spectrum, which can be studied with the Reflection Grating
Spectrometer. The emission features have been analysed at high resolution with
unprecedented detail for this source. Line ratios diagnostic from H-like and
He-like ions indicates that the line emission arises in X-ray photoionised
plasma. Extensive simulations have been performed with the CLOUDY
photoionisation code. From the comparison of the expected and observed line
intensities the physical properties of the line emitting material were derived.
Because of the degeneracy in the ionisation parameter, a number of different
solutions in terms of electron density and column density of the gas are
consistent with the spectral diagnostics. This prevents us from determining
uniquely the properties of the plasma; however, the location(s) of the X-ray
photoionised gas can be constrained to be within 0.06 pc (outer boundary). This
limit places the X-ray line emitting gas at the inner edge of the material
where the broad optical lines are produced (Broad Line Region).


title:
Spatial Structure and Collisionless Electron Heating in Balmer-dominated
  Shocks

abstract:
  Balmer-dominated shocks in supernova remnants (SNRs) produce strong hydrogen
lines with a two-component profile composed of a narrow contribution from cold
upstream hydrogen atoms, and a broad contribution from hydrogen atoms that have
undergone charge transfer reactions with hot protons. Observations of emission
lines from edge-wise shocks in SNRs can constrain the gas velocity and
collisionless electron heating at the shock front. Downstream hydrogen atoms
engage in charge transfer, excitation and ionization reactions, defining an
interaction region called the shock transition zone. The properties of hot
hydrogen atoms produced by charge transfers (called broad neutrals) are
critical for accurately calculating the structure and radiation from the shock
transition zone. This paper is the third in a series describing the kinetic,
fluid and emission properties of Balmer-dominated shocks, and is the first to
properly treat the effect of broad neutral kinetics on shock transition zone
structure. We use our models to extract shock parameters from observations of
Balmer-dominated SNRs. We find that inferred shock velocities and electron
temperatures are lower than those of previous calculations by <10% for v_s<1500
km/s, and by 10-30% for v_s>1500 km/s. This effect is primarily due to the fact
that excitation by proton collisions and charge transfer to excited levels
favor the high speed part of the neutral hydrogen velocity distribution. Our
results have a strong dependence on the ratio of electron to proton
temperatures, \beta=T_e/T_p, which allows us to construct a relation \beta(v_s)
between the temperature ratio and shock velocity. We compare our calculations
to previous results by Ghavamian et al. (2007).


title: Iterated Integrals and higher order automorphic forms

abstract:
  Higher order automorphic forms have recently been introduced to study
important questions in number theory and mathematical physics. We investigate
the connection between these functions and Chen's iterated integrals. Then
using Chen's theory, we prove a structure theorem for automorphic forms of all
orders. This allows us to define an analogue of a mixed Hodge structure on a
space of higher order automorphic forms.


title:
Optical Albedo Theory of Strongly-Irradiated Giant Planets: The Case of
  HD 209458b

abstract:
  We calculate a new suite of albedo models for close-in extrasolar giant
planets and compare with the recent stringent upper limit for HD 209458b of
Rowe et al. using MOST. We find that all models without scattering clouds are
consistent with this optical limit. We explore the dependence on wavelength and
waveband, metallicity, the degree of heat redistribution, and the possible
presence of thermal inversions and find a rich diversity of behaviors.
Measurements of transiting extrasolar giant planets (EGPs) at short wavelengths
by MOST, Kepler, and CoRoT, as well as by proposed dedicated multi-band
missions, can complement measurements in the near- and mid-IR using {\it
Spitzer} and JWST. Collectively, such measurements can help determine
metallicity, compositions, atmospheric temperatures, and the cause of thermal
inversions (when they arise) for EGPs with a broad range of radii, masses,
degrees of stellar insolation, and ages. With this paper, we reappraise and
highlight the diagnostic potential of albedo measurements of hot EGPs shortward
of $\sim$1.3 $\mu$m.


title:
Swift J1753.5-0127: The Black Hole Candidate with the shortest orbital
  period

abstract:
  We present time-resolved photometry of the optical counterpart to the black
hole candidate Swift J1753.5-0127, which has remained in the low/hard X-ray
state and bright at optical/IR wavelengths since its discovery in 2005. At the
time of our observations Swift J1753.5-0127 does not show a decay trend but
remains stable at R=16.45 with a night to night variability of ~0.05 mag. The
R-band light curves, taken from 2007 June 3 to August 31, are not sinusoidal,
but exhibit a complex morphology with remarkable changes in shape and
amplitude. The best period determination is 3.2443+-0.0010 hours. This
photometric period is likely a superhump period, slightly larger than the
orbital period. Therefore, Swift J1753.5-0127 is the black hole candidate with
the shortest orbital period observed to date. Our estimation of the distance is
comparable to values previously published and likely places Swift J1753.5-0127
in the Galactic halo.


title:
Detection of hot gas in the filament connecting the clusters of galaxies
  Abell 222 and Abell 223

abstract:
  About half of the baryons in the local Universe are invisible and - according
to simulations - their dominant fraction resides in filaments connecting
clusters of galaxies in the form of low density gas with temperatures in the
range of 10^5<T<10^7 K. The existence of this warm-hot intergalactic medium was
never unambiguously proven observationally in X-rays. We probe the low gas
densities expected in the large scale structure filaments by observing a
filament connecting the massive clusters of galaxies A 222 and A 223 (z=0.21)
which has a favorable orientation approximately along our line of sight. This
filament has been previously detected using weak lensing data and as an
over-density of colour selected galaxies. We analyse X-ray images and spectra
obtained in a deep observation (144 ks) of A 222/223 with XMM-Newton. We
present here observational evidence of the X-ray emission from the filament
connecting the two clusters. We detect the filament in the wavelet decomposed
soft band (0.5-2.0 keV) X-ray image with a 5 sigma significance. Following the
emission down to 3 sigma significance, the observed filament is approximately
1.2 Mpc wide. The temperature of the gas associated with the filament
determined from the spectra is kT=0.91\pm0.25 keV and its emission measure
corresponds to a baryon density of (3.4\pm1.3)x10^-5 (l/15Mpc)^-1/2 cm^-3,
where l is the length of the filament along the line of sight. This density
corresponds to a baryon over-density of approximately 150. The properties of
the gas in the filament are consistent with the results of simulations for the
densest and hottest parts of the warm-hot intergalactic medium.


title: Local Fluid Dynamical Entropy from Gravity

abstract:
  Spacetime geometries dual to arbitrary fluid flows in strongly coupled N=4
super Yang Mills theory have recently been constructed perturbatively in the
long wavelength limit. We demonstrate that these geometries all have regular
event horizons, and determine the location of the horizon order by order in a
boundary derivative expansion. Intriguingly, the derivative expansion allows us
to determine the location of the event horizon in the bulk as a local function
of the fluid dynamical variables. We define a natural map from the boundary to
the horizon using ingoing null geodesics. The area-form on spatial sections of
the horizon can then be pulled back to the boundary to define a local entropy
current for the dual field theory in the hydrodynamic limit. The area theorem
of general relativity guarantees the positivity of the divergence of the
entropy current thus constructed.