title: Ettore Majorana's Scientific (and Human) Personality

abstract:
  This article, in English, represents part of the invited talk delivered by
the author at the "Internat.Conf.Majorana Legacy and Phys. XXI century" held at
Dep. of Phys.,University of Catania, Italy, in Oct.2006: Conference organized
for celebrating the 100th anniversary of the birth (in Catania) of the Italian
theoretical physicist Ettore Majorana; probably the brightest Italian
theoretician of the XX century (Enrico Fermi regarded him as the brightest in
the world of his time), even if to some people Majorana is still known chiefly
for his mysterious disappearance, in 1938, when he was 31. In this writing we
outline the significance of his main publications, as well as his life: The
biographical data being based on letters, documents, testimonies discovered or
collected by the author during almost 30 years, and contained in the book by
E.Recami, "Il Caso Majorana: Epistolario, Testimonianze, Documenti" (initially
published, in 1987 and 1991, by Mondadori, Milan, and presenly published, in
2002, by Di Renzo Editore, Rome: http://www.direnzo.it). At last, some
information and comments are added with regard to the scientific manuscripts
left unpublished by Majorana.
  -----
  Ettore Majorana: Un cenno alle sue Opere (e Vita). Il secondo articolo
rappresenta la versione italiana di parte del seminario su invito tenuto
dall'autore alla "Internat.Conf.Majorana's Legacy and Phys. of XXI Century" che
ha avuto luogo nell'ottobre 2006 presso il Dip. di Fis. della Univ. di Catania:
Conferenza organizzata per celebrare il centenario della nascita (a Catania)
del fisico teorico Ettore Majorana; probabilmente il piu` geniale teorico
italiano del XX secolo (Enrico Fermi lo considero` il piu` brillante del suo
tempo nel mondo), anche se a qualcuno Majorana e` ancora noto soprattutto per
la sua misteriosa scomparsa, avvenuta nel 1938, quando aveva 31 anni. In questo
scritto descriviamo in sintesi tanto il significato delle sue piu` importanti
pubblicazioni, quanto la sua vita: i dati biografici essendo basati su lettere,
documenti, testimonianze scoperti o raccolti dall'autore durante quasi 30 anni,
e contenuti nel libro di E.Recami: "Il Caso Majorana: Epistolario,
Testimonianze, Documenti" (pubblicato inizialmente da Mondadori, Milano, nel
1987 e 1991, e al presente pubblicato, nel 2002, da Di Renzo Editore, Roma:
http://www.direnzo.it). Infine, si aggiungono informazioni e commenti circa i
manoscritti scientifici lasciti inediti dal Majorana.


title:
Theoretical analysis of magnetic coupling in sandwich clusters
  V_n(C_6H_6)_{n+1}

abstract:
  The mechanism of ferromagnetism stability in sandwich clusters
V$_n$(C$_6$H$_6$)$_{n+1}$ has been studied by first-principles calculation and
model analysis. It is found that each of the three types of bonds between V and
benzene (Bz) plays different roles. V 3d$_{z^2}$ orbital, extending along the
molecular axis, is weakly hybridized with Bz's HOMO-1 orbital to form the
$\sigma$-bond. It is quite localized and singly occupied, which contributes
1$\mu_B$ to the magnetic moment but little to the magnetic coupling of
neighboring V magnetic moments. The in-plane d$_{x^2-y^2}$, d$_{xy}$ orbitals
are hybridized with the LUMO of Bz and constitute the $\delta$-bond. This
hybridization is medium and crucial to the magnetic coupling though the
$\delta$ states have no net contribution to the total magnetic moment.
d$_{xz}$, d$_{yz}$ and HOMO of Bz form a quite strong $\pi$-bond to hold the
molecular structure but they are inactive in magnetism because their energy
levels are far away from the Fermi level. Based on the results of
first-principles calculation, we point out that the ferromagnetism stability is
closely related with the mechanism proposed by Kanamori and Terakura [J.
Kanamori and K. Terakura, J. Phys. Soc. Jpn. 70, 1433 (2001)]. However, the
presence of edge Bz's in the cluster introduces an important modification. A
simple model is constructed to explain the essence of the physical picture.


title:
Spatial image of reaction area from scattering I: SO_mu(2.1) algebra
  formalism

abstract:
  We develop general formalism of how to relate scattering amplitudes for
exclusive processes to spatial image of target hadron. More precisely we show
how to determine the spatial distribution of outgoing particles in the space of
so-called nearest approach parameter. This parameter characterizes the position
in the coordinate space the place where the final particle is produced.


title: Dimer diffusion in a washboard potential

abstract:
  The transport of a dimer, consisting of two Brownian particles bounded by a
harmonic potential, moving on a periodic substrate is investigated both
numerically and analytically. The mobility and diffusion of the dimer center of
mass present distinct properties when compared with those of a monomer under
the same transport conditions. Both the average current and the diffusion
coefficient are found to be complicated non-monotonic functions of the driving
force. The influence of dimer equilibrium length, coupling strength and damping
constant on the dimer transport properties are also examined in detail.


title:
Studies of self-organized Nanostructures on InP(111) surfaces after low
  energy Ar+ ion irradiation

abstract:
  We report formation of self organized InP nano dots using 3 keV Ar+ ion
sputtering, at $15^\circ$ incidence from surface normal, on InP(111) surface.
Morphology and optical properties of the sputtered surface, as a function of
sputtering time, have been investigated by Scanning Probe Microscopy and Raman
Scattering techniques. Uniform patterns of nano dots are observed for different
durations of sputtering. The sizes and the heights of these nano dots vary
between 10 to 100 nm and 20 to 40 nm, respectively. With increasing of
sputtering time, t, the size and height of these nano dots increases up to a
certain sputtering time $t_c$. However beyond $t_c$, the dots break down into
smaller nanostructures, and as a result, the size and height of these
nanostructures decrease. The uniformity and regularity of these structures are
also lost for sputtering beyond $t_c$. The crossover behavior is also observed
in the rms surface roughness. Raman investigations of InP nano dots reveal
optical phonon softening due to phonon confinement in the surface nano dots.


title: Three-loop Corrections in a Covariant Effective Field Theory

abstract:
  Chiral effective field theories have been used with success in the study of
nuclear structure. It is of interest to systematically improve these energy
functionals (particularly that of quantum hadrodynamics) through the inclusion
of many-body correlations. One possible source of improvement is the loop
expansion. Using the techniques of Infrared Regularization, the short-range,
local dynamics at each order in the loops is absorbed into the parameterization
of the underlying effective lagrangian. The remaining nonlocal, exchange
correlations must be calculated explicitly. Given that the interactions of
quantum hadrodynamics are relatively soft, the loop expansion may be manageable
or even perturbative in nuclear matter. This work investigates the role played
by the three-loop contributions to the loop expansion for quantum
hadrodynamics.


title:
Poisson sigma models on surfaces with boundary: classical and quantum
  aspects

abstract:
  The topics covered in this thesis may be divided into three parts. Firstly,
we perform a study on the most general branes which are consistent with the
Poisson sigma model, both at the classical and quantum levels. The second part
is devoted to the particular case in which the target Poisson manifold is a
Poisson-Lie group. Finally, we investigate the supersymmetric version of the
twisted Poisson sigma model and its connection with twisted generalized complex
geometry.


title:
Quasi two-dimensional carriers in dilute-magnetic-semiconductor quantum
  wells under in-plane magnetic field

abstract:
  Due to the competition between spatial and magnetic confinement, the density
of states of a quasi two-dimensional system deviates from the ideal step-like
form both quantitatively and qualitatively. We study how this affects the
spin-subband populations and the spin-polarization as functions of the
temperature, $T$, and the in-plane magnetic field, $B$, for narrow to wide
dilute-magnetic-semiconductor quantum wells. We focus on the quantum well
width, the magnitude of the spin-spin exchange interaction, and the sheet
carrier concentration dependence. We look for ranges where the system is
completely spin-polarized. Increasing $T$, the carrier spin-splitting,
$U_{o\sigma}$, decreases, while increasing $B$, $U_{o\sigma}$ increases.
Moreover, due to the density of states modification, all energetically higher
subbands become gradually depopulated.


title:
The Arecibo Methanol Maser Galactic Plane Survey - II: Statistical and
  Multi-wavelength Counterpart Analysis

abstract:
  We present an analysis of the properties of the 6.7 GHz methanol maser sample
detected in the Arecibo Methanol Maser Galactic Plane Survey. The distribution
of the masers in the Galaxy, and statistics of their multi-wavelength
counterparts is consistent with the hypothesis of 6.7 GHz maser emission being
associated with massive young stellar objects. Using the detection statistics
of our survey, we estimate the minimum number of methanol masers in the Galaxy
to be 1275. The l-v diagram of the sample shows the tangent point of the
Carina-Sagittarius spiral arm to be around 49.6 degrees, and suggests
occurrence of massive star formation along the extension of the Crux-Scutum
arm. A Gaussian component analysis of the maser spectra shows the mean
line-width to be 0.38 km/s which is more than a factor of two larger than what
has been reported in the literature. We also find no evidence that faint
methanol masers have different properties than those of their bright
counterparts.


title: Lattice study of monopoles in the Electroweak theory

abstract:
  We investigated numerically properties of Nambu monopoles in lattice
Electroweak theory at realistic values of $\alpha$ and $\theta_W$. Our choice
of parameters of lattice Lagrangian corresponds to large values of the Higgs
boson mass $M_H > 2 M_W$.
  We find that the density of Nambu monopoles cannot be predicted by the choice
of the initial parameters of Electroweak theory and should be considered as the
new external parameter of the theory. We also investigate the difference
between the versions of Electroweak theory with the gauge groups $SU(2)\otimes
U(1)$ and $SU(2)\otimes U(1)/Z_2$. We do not detect any difference at $\alpha
\sim {1/128}$. However, such a difference appears in the strong coupling region
and is related to the properties of monopoles constructed of the hypercharge
field.


title: Lectures on Cosmic Inflation and its Potential Stringy Realizations

abstract:
  These notes present a brief introduction to Hot Big Bang cosmology and Cosmic
Inflation, together with a selection of some recent attempts to embed inflation
into string theory. They provide a partial description of lectures presented in
courses at Dubrovnik in August 2006, at CERN in January 2007 and at Cargese in
August 2007. They are aimed at graduate students with a working knowledge of
quantum field theory, but who are unfamiliar with the details of cosmology or
of string theory.


title: Precovers, localizations and stable homotopy

abstract:
  We prove a new localization theorem for stable model categories if the
localizing subcategory is generated by a precovering class in the model
category. We use this to show how one may explicitly realize certain Bousfield
localization functors that arise naturally in the study of relative homological
algebra for group algebras.


title:
Nuclear matter in the crust of neutron stars derived from realistic NN
  interactions

abstract:
  Properties of inhomogeneous nuclear matter are evaluated within a
relativistic mean field approximation using density dependent coupling
constants. A parameterization for these coupling constants is presented, which
reproduces the properties of the nucleon self-energy obtained in Dirac
Brueckner Hartree Fock calculations of asymmetric nuclear matter but also
provides a good description for bulk properties of finite nuclei. The
inhomogeneous infinite matter is described in terms of cubic Wigner-Seitz
cells, which allows for a microscopic description of the structures in the
so-called ``pasta-phase'' of nuclear configurations and provides a smooth
transition to the limit of homogeneous matter. The effects of pairing
properties and finite temperature are considered. A comparison is made to
corresponding results employing the phenomenological Skyrme Hartree-Fock
approach and the consequences for the Thomas-Fermi approximation are discussed.


title: Reduced Hamiltonian for intersecting shells

abstract:
  The gauge usually adopted for extracting the reduced Hamiltonian of a thin
spherical shell of matter in general relativity, becomes singular when dealing
with two or more intersecting shells. We introduce here a more general class of
gauges which is apt for dealing with intersecting shells. As an application we
give the hamiltonian treatment of two intersecting shells, both massive and
massless. Such a formulation is applied to the computation of the semiclassical
tunneling probability of two shells. The probability for the emission of two
shells is simply the product of the separate probabilities thus showing no
correlation in the emission probabilities in this model.


title: Nonlinearity in the dynamics of photoinduced nucleation process

abstract:
  Nonlinear dynamics of photoinduced cooperative phenomena is studied by
numerical calculations on a model of molecular crystals. We found that the
photoinduced nucleation process is triggered only when certain amount of
excitation energy is supplied in a narrow part of the system, i.e., there
exists a smallest cluster of excited molecules which makes the nucleation
possible. As a result, the portion of the cooperatively converted molecules is
nonlinearly dependent on the photoexcitation strength, which has been observed
in various materials.


title:
Electrical response of molecular systems: the power of self-interaction
  corrected Kohn-Sham theory

abstract:
  The accurate prediction of electronic response properties of extended
molecular systems has been a challenge for conventional, explicit density
functionals. We demonstrate that a self-interaction correction implemented
rigorously within Kohn-Sham theory via the Optimized Effective Potential (OEP)
yields polarizabilities close to the ones from highly accurate
wavefunction-based calculations and exceeding the quality of
exact-exchange-OEP. The orbital structure obtained with the OEP-SIC functional
and approximations to it are discussed.


title: Sharpness of the Finsler-Hadwiger inequality

abstract:
  In this paper we shall prove a sharpened version of the Finsler-Hadwiger
inequality which is a strong generalization of Weitzenbock inequality. After
that we give another refinement of this inequality and in the final part we
provide some basic applications.


title: Theory of induced quadrupolar order in tetragonal YbRu_{2}Ge_{2}

abstract:
  The tetragonal compound YbRu$_{2}$Ge$_{2}$ exhibits a non-magnetic transition
at $T_0$=10.2K and a magnetic transition at $T_1$=6.5K in zero magnetic field.
We present a model for this material based on a quasi-quartet of Yb$^{3+}$
crystalline electric field (CEF) states and discuss its mean field solution.
Taking into account the broadening of the specific heat jump at $T_0$ for
magnetic field perpendicular to [001] and the decrease of $T_0$ with magnetic
field parallel to [001], it is shown that ferro-quadrupole order of either
O$_{2}^{2}$ or O$_{\rm xy}$ - type are prime candidates for the non-magnetic
transition. Considering the matrix element of these quadrupole moments, we show
that the lower CEF states of the level scheme consist of a $\Gamma_{6}$ and a
$\Gamma_{7}$ doublet. This leads to induced type of O$_{2}^{2}$ and O$_{\rm
xy}$ quadrupolar order parameters. The quadrupolar order introduces exchange
anisotropy for planar magnetic moments. This causes a spin flop transition at
low fields perpendicular [001] which explains the observed metamagnetism. We
also obtain a good explanation for the temperature dependence of magnetic
susceptibility and specific heat for fields both parallel and perpendicular to
the [001] direction.


title: Global lopsided instability in a purely stellar galactic disc

abstract:
  It is shown that pure exponential discs in spiral galaxies are capable of
supporting slowly varying discrete global lopsided modes, which can explain the
observed features of lopsidedness in the stellar discs. Using linearized fluid
dynamical equations with the softened self-gravity and pressure of the
perturbation as the collective effect, we derive self-consistently a quadratic
eigenvalue equation for the lopsided perturbation in the galactic disc. On
solving this, we find that the ground-state mode shows the observed
characteristics of the lopsidedness in a galactic disc, namely the fractional
Fourier amplitude A$_1$ increases smoothly with the radius. These lopsided
patterns precess in the disc with a very slow pattern speed with no preferred
sense of precession. We show that the lopsided modes in the stellar disc are
long-lived because of a substantial reduction ($\sim$ a factor of 10 compared
to the local free precession rate) in the differential precession. The
numerical solution of the equations shows that the ground-state lopsided modes
are either very slowly precessing stationary normal mode oscillations of the
disc or growing modes with a slow growth rate depending on the relative
importance of the collective effect of the self-gravity. N-body simulations are
performed to test the spontaneous growth of lopsidedness in a pure stellar
disc. Both approaches are then compared and interpreted in terms of long-lived
global $m=1$ instabilities, with almost zero pattern speed.


title: Search for the Rare Decay K_{L}\to\pi^{0}\pi^{0}\gamma

abstract:
  The KTeV E799 experiment has conducted a search for the rare decay
$K_{L}\to\pi^{0}\pi^{0}\gamma$ via the topology
$K_{L}\to\pi^{0}\pi^{0}_D\gamma$ (where $\pi^0_D\to\gamma e^+e^-$). Due to Bose
statistics of the $\pi^0$ pair and the real nature of the photon, the
$K_{L}\to\pi^{0}\pi^{0}\gamma$ decay is restricted to proceed at lowest order
by the CP conserving direct emission (DE) of an E2 electric quadrupole photon.
The rate of this decay is interesting theoretically since chiral perturbation
theory predicts that this process vanishes at level $O(p^4)$. Therefore, this
mode probes chiral perturbation theory at $O(p^6)$. In this paper we report a
determination of an upper limit of $2.43\times 10^{-7}$ (90% CL) for
$K_{L}\to\pi^{0}\pi^{0}\gamma$. This is approximately a factor of 20 lower than
previous results.


title:
Surfing on the Edge: Chaos vs. Near-Integrability in the System of
  Jovian Planets

abstract:
  We demonstrate that the system of Jovian planets
(Sun+Jupiter+Saturn+Uranus+Neptune), integrated for 200 million years as an
isolated 5-body system using many sets of initial conditions all within the
uncertainty bounds of their currently known positions, can display both chaos
and near-integrability. The conclusion is consistent across four different
integrators, including several comparisons against integrations utilizing
quadruple precision. We demonstrate that the Wisdom-Holman symplectic map using
simple symplectic correctors as implemented in Mercury 6.2 (Chambers 1999)
gives a reliable characterization of the existence of chaos for a particular
initial condition only with timesteps less than about 10 days, corresponding to
about 400 steps per orbit. We also integrate the canonical DE405 initial
condition out to 5 Gy, and show that it has a Lyapunov Time of 200--400 My,
opening the remote possibility of accurate prediction of the Jovian planetary
positions for 5 Gy.


title: Tkachenko modes as sources of quasiperiodic pulsar spin variations

abstract:
  We study the long wavelength shear modes (Tkachenko waves) of triangular
lattices of singly quantized vortices in neutron star interiors taking into
account the mutual friction between the superfluid and the normal fluid and the
shear viscosity of the normal fluid. The set of Tkachenko modes that propagate
in the plane orthogonal to the spin vector are weakly damped if the coupling
between the superfluid and normal fluid is small. In strong coupling, their
oscillation frequencies are lower and are undamped for small and moderate shear
viscosities. The periods of these modes are consistent with the observed
~100-1000 day variations in spin of PSR 1828-11.


title:
The mid-infrared emission of Seyfert galaxies. A new analysis of ISOCAM
  data

abstract:
  We present mid-infrared data of a sample of 57 AGNs obtained with the
instrument ISOCAM on board the satellite ISO. The images were obtained through
the LW2 (6.75 microns) and LW7 (9.62 microns) filters. This is a new analysis
of Clavel et al. (2000) galaxy sample, which is divided into 26 type 1 (< or =
1.5) and 28 type 2 (> 1.5) Seyfert galaxies, plus three QSOs. The spatial
resolution of the images allow us to separate the nuclear and the extended
contributions to the total emission after decomposing the brightness profiles
into different morphological components. The most common components are a
central point source (identified as the active nucleus) and an exponential
disk. In some cases a bulge, a bar or a ring are needed. The relative
contribution of the nucleus to the total emission appears larger in Seyfert 1
than in Seyfert 2. This result confirms that both types of Seyfert galaxies are
different in the mid-infrared and supports the existence of an structure which
produces anisotropic emission in this wavelength range. We have also explored
correlations between the mid-infrared and the radio and X-ray wavelength
ranges. The well established radio/infrared correlation is mantained in our
sample for the global emission of the galaxies. If only the nuclear infrared
emission is considered then a non-linear correlation is apparent in the
luminosity-luminosity scatter diagram. The ratio between the intrinsic hard
X-ray and the nuclear mid-infrared emission presents large scatter and slightly
larger values for type 2 Seyfert galaxies. These results seem to be consistent
with the presence of a clumpy dusty torus surrounding the active nucleus.


title:
Noise thermometry and electron thermometry of a sample-on-cantilever
  system below 1 Kelvin

abstract:
  We have used two types of thermometry to study thermal fluctuations in a
microcantilever-based system below 1 K. We measured the temperature of a
cantilever's macroscopic degree-of-freedom (via the Brownian motion of its
lowest flexural mode) and its microscopic degrees-of-freedom (via the electron
temperature of a metal sample mounted on the cantilever). We also measured both
temperatures' response to a localized heat source. We find it possible to
maintain thermal equilibrium between these two temperatures and a refrigerator
down to at least 300 mK. These results are promising for ongoing experiments to
probe quantum effects using micromechanical devices.


title: On Shannon-Jaynes Entropy and Fisher Information

abstract:
  The fundamentals of the Maximum Entropy principle as a rule for assigning and
updating probabilities are revisited. The Shannon-Jaynes relative entropy is
vindicated as the optimal criterion for use with an updating rule. A
constructive rule is justified which assigns the probabilities least sensitive
to coarse-graining. The implications of these developments for interpreting
physics laws as rules of inference upon incomplete information are briefly
discussed.


title: Entanglement of superconducting charge qubits by homodyne measurement

abstract:
  We present a scheme by which projective homodyne measurement of a microwave
resonator can be used to generate entanglement between two superconducting
charge qubits coupled to this resonator. The non-interacting qubits are
initialised in a product of their ground states, the resonator is initialised
in a coherent field state, and the state of the system is allowed to evolve
under a rotating wave Hamiltonian. Making a homodyne measurement on the
resonator at a given time projects the qubits into an state of the form (|gg> +
exp(-i phi)|ee>)/sqrt(2). This protocol can produce states with a fidelity as
high as required, with a probability approaching 0.5. Although the system
described is one that can be used to display revival in the qubit oscillations,
we show that the entanglement procedure works at much shorter timescales.


title:
Spin-polarized tunneling currents through a ferromagnetic insulator
  between two metallic or superconducting leads

abstract:
  Using the Keldysh formalism the tunneling current through a hybrid structure
where a confined magnetic insulator (I) is sandwiched between two non-magnetic
leads is calculated. The leads can be either normal metals (M) or
superconductors (S). Each region is modelled as a single band in tight-binding
approximation in order to understand the formation of the tunneling current as
clearly as possible. The tunneling process itself is simulated by a
hybridization between the lead and insulator conduction bands. The insulator is
assumed to have localized moments which can interact with the tunneling
electrons. This is described by the Kondo Lattice Model (KLM) and treated
within an interpolating self-energy approach. For the superconductor the
mean-field BCS theory is used. The spin polarization of the current shows a
strong dependence both on the applied voltage and the properties of the
materials. Even for this idealized three band model there is a qualitative
agreement with experiment.


title:
Phase field model of interfaces in single-component systems derived from
  classical density functional theory

abstract:
  Phase field models have been applied in recent years to grain boundaries in
single-component systems. The models are based on the minimization of a free
energy functional, which is constructed phenomenologically rather than being
derived from first principles. In single-component systems the free energy is a
functional of a ``phase field'', which is an order parameter often referred to
as the crystallinity in the context of grain boundaries, but with no precise
definition as to what that term means physically. We present a derivation of
the phase field model by Allen and Cahn from classical density functional
theory first for crystal-liquid interfaces and then for grain boundaries. The
derivation provides a clear physical interpretation of the phase field, and it
sheds light on the parameters and the underlying approximations and limitations
of the theory. We suggest how phase field models may be improved.


title: Positive bases in spaces of polynomials

abstract:
  For a nonempty compact set D of R we determine the maximal possible dimension
of a subspace X of polynomial functions of degree at most m which possesses a
positive bases (where positivity is understood on D). The exact value of this
maximal dimension depends on topological features of the base set D. We show
that at many cases dimension m can be achieved.Whereas only for low m or finite
sets D it is possible to have m+1 (the full dimension of the space of
polynomials of degree at most m) dimensional subspace X with positive basis.
Therefore, it turns out that for no D it is possible to have a positive basis
of the polynomial space of degree at most m for all m in N.


title: Mid-Infrared interferometry of dust around massive evolved stars

abstract:
  We report long-baseline interferometric measurements of circumstellar dust
around massive evolved stars with the MIDI instrument on the Very Large
Telescope Interferometer and provide spectrally dispersed visibilities in the
8-13 micron wavelength band. We also present diffraction-limited observations
at 10.7 micron on the Keck Telescope with baselines up to 8.7 m which explore
larger scale structure. We have resolved the dust shells around the late type
WC stars WR 106 and WR 95, and the enigmatic NaSt1 (formerly WR 122), suspected
to have recently evolved from a Luminous Blue Variable (LBV) stage. For AG Car,
the protoypical LBV in our sample, we marginally resolve structure close to the
star, distinct from the well-studied detached nebula. The dust shells around
the two WC stars show fairly constant size in the 8-13 micron MIDI band, with
gaussian half-widths of ~ 25 to 40 mas. The compact dust we detect around NaSt1
and AG Car favors recent or ongoing dust formation.
  Using the measured visibilities, we build spherically symmetric radiative
transfer models of the WC dust shells which enable detailed comparison with
existing SED-based models. Our results indicate that the inner radii of the
shells are within a few tens of AU from the stars. In addition, our models
favor grain size distributions with large (~ 1 micron) dust grains. This
proximity of the inner dust to the hot central star emphasizes the difficulty
faced by current theories in forming dust in the hostile environment around WR
stars. Although we detect no direct evidence for binarity for these objects,
dust production in a colliding-wind interface in a binary system is a feasible
mechanism in WR systems under these conditions.


title: Measurement of B -> D_s K pi branching ratios

abstract:
  We report a measurement of the exclusive $B^+$ meson decay to the final state
$D_s^- K^+\pi^+$ using $520 \times 10^{6} B\bar{B}$ pairs collected near the
$\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric-energy
$e^+e^-$ collider. Using the $D_S^- \to \phi \pi^-$ decay mode to reconstruct
$D_s^-$ mesons, we obtain the branching fraction ${\cal B}(B^+\to
D_s^-K^+\pi^+)= (1.77^{+0.12}_{-0.12} {\mathrm (stat)} \pm 0.16 {\mathrm
(syst)} \pm 0.23 {\cal(B)})\times 10^{-4}$. We also present preliminary results
of a study of the two-body $D_sK$, $D_s\pi$ and $K\pi$ subsystems observed in
this final state.


title: Polynomial Structure of the (Open) Topological String Partition Function

abstract:
  In this paper we show that the polynomial structure of the topological string
partition function found by Yamaguchi and Yau for the quintic holds for an
arbitrary Calabi-Yau manifold with any number of moduli. Furthermore, we
generalize these results to the open topological string partition function as
discussed recently by Walcher and reproduce his results for the real quintic.


title: Bordered Riemann surfaces in C^2

abstract:
  One of the oldest open problems in the classical function theory is whether
every open Riemann surface admits a proper holomorphic embedding into C^2. In
this paper we prove the following Theorem: If D is a bordered Riemann surface
whose closure admits an injective immersion in C^2 that is holomorphic in D,
then D admits a proper holomorphic embedding in C^2. The most general earlier
results are due to J. Globevnik and B. Stensones (Math. Ann. 303 (1995),
579-597) and E. F. Wold (Internat. J. Math. 17 (2006), 963-974). We give an
explicit and elementary construction that does not require the Teichmuller
space theory, and we also indicate another possible proof using the latter
theory.


title: Another look at the problem of gauge invariance in QFT

abstract:
  It is generally assumed that quantum field theory (QFT) is gauge invariant.
However it is well known that non-gauge invariant terms appear in various
calculations. This problem was examined in Refs. [3] and [4] and it was shown
that at the formal level QFT in the Schroedinger picture is not, in fact, gauge
invariant. It was determined that this problem was due to a mathematical
inconsistency related to the way the vacuum state is defined. In order to shed
further light on this problem we consider a simple field theory in 1-1D
space-time consisting of a quantized fermion field with zero mass in the
presence of a classical electromagnetic potential. It can easily be shown that
for this situation the equations of motion can be solved exactly in both the
Heisenberg and Schroedinger pictures. This allows us to easily identify the
source of the mathematical inconsistency that appears in QFT.


title:
Probing quantum gravity using photons from a flare of the active
  galactic nucleus Markarian 501 observed by the MAGIC telescope

abstract:
  We analyze the timing of photons observed by the MAGIC telescope during a
flare of the active galactic nucleus Mkn 501 for a possible correlation with
energy, as suggested by some models of quantum gravity (QG), which predict a
vacuum refractive index \simeq 1 + (E/M_{QGn})^n, n = 1,2. Parametrizing the
delay between gamma-rays of different energies as \Delta t =\pm\tau_l E or
\Delta t =\pm\tau_q E^2, we find \tau_l=(0.030\pm0.012) s/GeV at the 2.5-sigma
level, and \tau_q=(3.71\pm2.57)x10^{-6} s/GeV^2, respectively. We use these
results to establish lower limits M_{QG1} > 0.21x10^{18} GeV and M_{QG2} >
0.26x10^{11} GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC
sensitivity to propagation effects at these levels. Thermal plasma effects in
the source are negligible, but we cannot exclude the importance of some other
source effect.


title: Linear maps preserving invariants

abstract:
  Let $G\subset\GL(V)$ be a complex reductive group. Let $G'$ denote
$\{\phi\in\GL(V)\mid p\circ\phi=p\text{for all} p\in\C[V]^G\}$. We show that,
in general, $G'=G$. In case $G$ is the adjoint group of a simple Lie algebra
$\lieg$, we show that $G'$ is an order 2 extension of $G$. We also calculate
$G'$ for all representations of $\SL_2$.


title: Magnons in Ferromagnetic Metallic Manganites

abstract:
  Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of
special interest not only because they are a testing ground of the classical
doubleexchange interaction mechanism for the colossal magnetoresistance, but
also because they exhibit an extraordinary arena of emergent phenomena. These
emergent phenomena are related to the complexity associated with strong
interplay between charge, spin, orbital, and lattice. In this review, we focus
on the use of inelastic neutron scattering to study the spin dynamics, mainly
the magnon excitations in this class of FM metallic materials. In particular,
we discussed the unusual magnon softening and damping near the Brillouin zone
boundary in relatively narrow band compounds with strong Jahn-Teller lattice
distortion and charge/orbital correlations. The anomalous behaviors of magnons
in these compounds indicate the likelihood of cooperative excitations involving
spin, lattice, as well as orbital degrees of freedom.


title:
Comparison of hybrid and pure Monte Carlo shower generators on an event
  by event basis

abstract:
  SENECA is a hybrid air shower simulation written by H. Drescher that utilizes
both Monte Carlo simulation and cascade equations. By using the cascade
equations only in the high energy portion of the shower, where the shower is
inherently one-dimensional, SENECA is able to utilize the advantages in speed
from the cascade equations yet still produce complete, three dimensional
particle distributions at ground level which capture the shower to shower
variations coming from the early interactions. We present a comparison, on an
event by event basis, of SENECA and CORSIKA, a well trusted MC simulation code.
By using the same first interaction in both SENECA and CORSIKA, the effect of
the cascade equations can be studied within a single shower, rather than
averaged over many showers. Our study shows that for showers produced in this
manner, SENECA agrees with CORSIKA to a very high accuracy with respect to
densities, energies, and timing information for individual species of
ground-level particles from both iron and proton primaries with energies
between 1 EeV and 100 EeV. Used properly, SENECA produces ground particle
distributions virtually indistinguishable from those of CORSIKA in a fraction
of the time. For example, for a shower induced by a 10 EeV proton, SENECA is 10
times faster than CORSIKA, with comparable accuracy.


title: Fast Recursive Coding Based on Grouping of Symbols

abstract:
  A novel fast recursive coding technique is proposed. It operates with only
integer values not longer 8 bits and is multiplication free. Recursion the
algorithm is based on indirectly provides rather effective coding of symbols
for very large alphabets. The code length for the proposed technique can be up
to 20-30% less than for arithmetic coding and, in the worst case it is only by
1-3% larger.


title: On the growth of the Bergman kernel near an infinite-type point

abstract:
  We study diagonal estimates for the Bergman kernels of certain model domains
in $\mathbb{C}^2$ near boundary points that are of infinite type. To do so, we
need a mild structural condition on the defining functions of interest that
facilitates optimal upper and lower bounds. This is a mild condition; unlike
earlier studies of this sort, we are able to make estimates for non-convex
pseudoconvex domains as well. This condition quantifies, in some sense, how
flat a domain is at an infinite-type boundary point. In this scheme of
quantification, the model domains considered below range -- roughly speaking --
from being ``mildly infinite-type'' to very flat at the infinite-type points.


title: Random Matrices: The circular Law

abstract:
  Let $\a$ be a complex random variable with mean zero and bounded variance
$\sigma^{2}$. Let $N_{n}$ be a random matrix of order $n$ with entries being
i.i.d. copies of $\a$. Let $\lambda_{1}, ..., \lambda_{n}$ be the eigenvalues
of $\frac{1}{\sigma \sqrt n}N_{n}$. Define the empirical spectral distribution
$\mu_{n}$ of $N_{n}$ by the formula $$ \mu_n(s,t) := \frac{1}{n} # \{k \leq n|
\Re(\lambda_k) \leq s; \Im(\lambda_k) \leq t \}.$$
  The Circular law conjecture asserts that $\mu_{n}$ converges to the uniform
distribution $\mu_\infty$ over the unit disk as $n$ tends to infinity.
  We prove this conjecture under the slightly stronger assumption that the
$(2+\eta)\th$-moment of $\a$ is bounded, for any $\eta >0$. Our method builds
and improves upon earlier work of Girko, Bai, G\"otze-Tikhomirov, and Pan-Zhou,
and also applies for sparse random matrices.
  The new key ingredient in the paper is a general result about the least
singular value of random matrices, which was obtained using tools and ideas
from additive combinatorics.


title:
Approximating a Wavefunction as an Unconstrained Sum of Slater
  Determinants

abstract:
  The wavefunction for the multiparticle Schr\"odinger equation is a function
of many variables and satisfies an antisymmetry condition, so it is natural to
approximate it as a sum of Slater determinants. Many current methods do so, but
they impose additional structural constraints on the determinants, such as
orthogonality between orbitals or an excitation pattern. We present a method
without any such constraints, by which we hope to obtain much more efficient
expansions, and insight into the inherent structure of the wavefunction. We use
an integral formulation of the problem, a Green's function iteration, and a
fitting procedure based on the computational paradigm of separated
representations. The core procedure is the construction and solution of a
matrix-integral system derived from antisymmetric inner products involving the
potential operators. We show how to construct and solve this system with
computational complexity competitive with current methods.


title:
Diagrammatic bounds on the lace-expansion coefficients for oriented
  percolation

abstract:
  We provide a complete proof of the diagrammatic bounds on the lace-expansion
coefficients for oriented percolation, which are used in [arXiv:math/0703455]
to investigate critical behavior for long-range oriented percolation above
2\min{\alpha,2} spatial dimensions.


title: On solutions to Walcher's extended holomorphic anomaly equation

abstract:
  We give a generalization of Yamaguchi--Yau's result to Walcher's extended
holomorphic anomaly equation.


title: A rigidity theorem for holomorphic generators on the Hilbert ball

abstract:
  We present a rigidity property of holomorphic generators on the open unit
ball $\mathbb{B}$ of a Hilbert space $H$. Namely, if $f\in\Hol (\mathbb{B},H)$
is the generator of a one-parameter continuous semigroup ${F_t}_{t\geq 0}$ on
$\mathbb{B}$ such that for some boundary point $\tau\in \partial\mathbb{B}$,
the admissible limit $K$-$\lim\limits_{z\to\tau}\frac{f(x)}{\|x-\tau\|^{3}}=0$,
then $f$ vanishes identically on $\mathbb{B}$.


title: The geometry of Minkowski spaces -- a survey. Part I

abstract:
  We survey elementary results in Minkowski spaces (i.e. finite dimensional
Banach spaces) that deserve to be collected together, and give simple proofs
for some of them. We place special emphasis on planar results. Many of these
results have often been rediscovered as lemmas to other results. In Part I we
cover the following topics: The triangle inequality and consequences such as
the monotonicity lemma, geometric characterizations of strict convexity,
normality (Birkhoff orthogonality), conjugate diameters and Radon curves,
equilateral triangles and the affine regular hexagon construction, equilateral
sets, circles: intersection, circumscribed, characterizations, circumference
and area, inscribed equilateral polygons.


title: Magnetogenesis from Cosmic String Loops

abstract:
  Large-scale coherent magnetic fields are observed in galaxies and clusters,
but their ultimate origin remains a mystery. We reconsider the prospects for
primordial magnetogenesis by a cosmic string network. We show that the magnetic
flux produced by long strings has been overestimated in the past, and give
improved estimates. We also compute the fields created by the loop population,
and find that it gives the dominant contribution to the total magnetic field
strength on present-day galactic scales. We present numerical results obtained
by evolving semi-analytic models of string networks (including both one-scale
and velocity-dependent one-scale models) in a Lambda-CDM cosmology, including
the forces and torques on loops from Hubble redshifting, dynamical friction,
and gravitational wave emission. Our predictions include the magnetic field
strength as a function of correlation length, as well as the volume covered by
magnetic fields. We conclude that string networks could account for magnetic
fields on galactic scales, but only if coupled with an efficient dynamo
amplification mechanism.


title: Monte Carlo simulation results for critical Casimir forces

abstract:
  The confinement of critical fluctuations in soft media induces critical
Casimir forces acting on the confining surfaces. The temperature and geometry
dependences of such forces are characterized by universal scaling functions. A
novel approach is presented to determine them for films via Monte Carlo
simulations of lattice models. The method is based on an integration scheme of
free energy differences. Our results for the Ising and the XY universality
class compare favourably with corresponding experimental results for wetting
layers of classical binary liquid mixtures and of 4He, respectively.


title:
Fixed point scenario in the Two Higgs Doublet Model inspired by
  degenerate vacua

abstract:
  We consider the renormalisation group flow of Higgs and Yukawa couplings
within the simplest non--supersymmetric two Higgs doublet extension of the
Standard Model (SM). In this model the couplings are adjusted so that the
multiple point principle (MPP) assumption, which implies the existence of a
large set of degenerate vacua at some high energy scale $\Lambda$, is realised.
When the top quark Yukawa coupling at the scale $\Lambda$ is large, the
solutions of RG equations in this MPP inspired 2 Higgs Doublet Model (2HDM)
converge to quasi--fixed points. We analyse the Higgs spectrum and couplings in
the quasi--fixed point scenario and compute a theoretical upper bound on the
lightest Higgs boson mass. When the scale $\Lambda$ is low, the coupling of the
SM--like Higgs scalar to the top quark can be significantly larger in the
considered model than in the SM, resulting in the enhanced production of Higgs
bosons at the LHC.


title:
Possible evidence of a ground level enhancement of muons in association
  with a SWIFT Trigger

abstract:
  Starting from April 2007, a search for solar daily variation of the muon
intensity ($E_\mu >0.2$ GeV) at sea level and using two directional muon
telescopes is in progress. In this survey, several ground level enhancements
(GLEs) on the muon counting rate background have been found. Here, we highlight
one of them, observed in the vertical telescope on 07 August 2007 for the
following reasons: The GLE consists of a single narrow peak, with a statistical
significance of 4.4$\sigma$. The GLE is in temporal coincidence with a SWIFT
trigger $N^0287222$, at 21:16:05 UT according to the Burst Alert Telescope
(BAT) on board of the SWIFT spacecraft. However, the Swift StarTracker had lost
stellar lock minutes before that and the resulting improper s/c attitude
information caused BAT to "trigger" on a known source. Even so, the SWIFT
trigger coordinates are inside the effective field of view of the vertical Tupi
muon telescope. The temporal and directional coincidences between this GLE and
the SWIFT satellite unknown event strongly suggest that they may be physically
associated. Details and implications of this possible association are reported
in this work.


title:
Enhanced Higgs boson production and avoidance of CP-violation and FCNC
  in the MPP inspired 2HDM

abstract:
  The multiple point principle (MPP) can be used to suppress non--diagonal
flavour transitions and CP violation in the two Higgs doublet extension of the
standard model. We discuss the quasi--fixed point scenario in the MPP inspired
two Higgs doublet model which leads to the enhanced production of Higgs
particles at the LHC if the MPP scale is low.


title: The general relativistic infinite plane

abstract:
  Uniform fields are one of the simplest and most pedagogically useful examples
in introductory courses on electrostatics or Newtonian gravity. In general
relativity there have been several proposals as to what constitutes a uniform
field. In this article we examine two metrics that can be considered the
general relativistic version of the infinite plane with finite mass per unit
area. The first metric is the 4D version of the 5D "brane" world models which
are the starting point for many current research papers. The second case is the
cosmological domain wall metric. We examine to what extent these different
metrics match or deviate from our Newtonian intuition about the gravitational
field of an infinite plane. These solutions provide the beginning student in
general relativity both computational practice and conceptual insight into
Einstein's field equations. In addition they do this by introducing the student
to material that is at the forefront of current research.


title: Smallness of the cosmological constant and the multiple point principle

abstract:
  In this talk we argue that the breakdown of global symmetries in no--scale
supergravity (SUGRA), which ensures the vanishing of the vacuum energy density
near the physical vacuum, leads to a natural realisation of the multiple point
principle (MPP). In the MPP inspired SUGRA models the cosmological constant is
naturally tiny.


title: Optimal control of molecular electronics by femtosecond laser pulses

abstract:
  Combining the features of molecular wires and femtosecond laser pulses gives
the unique opportunity to optically switch electron currents in molecular
devices with very high speed. Based on a weak-coupling approximation between
wire and leads a quantum master equation for the population dynamics and the
electric current through the molecular wire has been developed which allows for
arbitrary time-dependent laser fields interacting with the wire. This formalism
is combined with the theory of optimal control. For a tight-binding
approximation of the wire we show how to compute the laser pulses to switch the
current through the wire on and off. With this approach the desired pattern of
the current in time can be chosen in an almost arbitrary fashion.


title: Testing the Topology of Reionization

abstract:
  The central overlap phase of cosmological hydrogen reionization is
fundamentally a change in the topology of ionized regions. Before overlap,
ionized bubbles grew in isolation. During overlap, they merge into a
percolating ionized medium, which fills an ever-increasing volume and
eventually replaces neutral gas throughout the intergalactic medium. Overlap
can therefore be well studied using topological statistics, and in particular
the genus number of the neutral-ionized interface. The most promising
observational tools for applying such tests are (a) Lyman alpha galaxies, and
(b) 21 cm tomography. Lyman alpha galaxies will be detected whenever they
inhabit bubbles larger than 1 physical Mpc, and their presence can therefore be
used to map such bubbles. Such large bubbles are expected during the overlap
phase, and moreover, each one should contain a few detectably bright Lyman
alpha galaxies. The 21cm line in principle affords better spatial resolution,
but the required sensitivity and foreground subtraction may be an issue.
Upcoming Lyman alpha surveys in the near-infrared could thus provide our first
look at the topology of reionization.


title: A Note on Agegraphic Dark Energy

abstract:
  Recently a new model of dynamical dark energy, or time-varying $\Lambda$, was
proposed by Cai [arXiv:0707.4049] by relating the energy density of quantum
fluctuations in a Minkowski space-time, namely $\rho_q \equiv 3 n^2 m_P^2/t^2$,
where $n\sim {\cal O}(1)$ and t is the cosmic time, to the present day dark
energy density. In this note, we show that the model can be adjusted to the
present values of dark energy density parameter $\Omega_q$ ($\simeq 0.73$) and
the equation of state ${\rm w}\Z{q}$ ($\simeq -1$) only if the numerical
coefficient $n$ takes a reasonably large value ($n\gtrsim 3$) or the present
value of the gravitational coupling of q-field to (dark) matter is also
nonzero, namely, $\tilde{Q}\simeq \frac{2}{n}(\Omega\Z{q0})^{3/2}>0$ where
$\Omega\Z{q0}$ is the present value of dark energy density fraction. We also
discuss some of the difficulties of this proposal as a viable dark energy model
with a constant $n$; especially, the bound imposed on the dark energy density
parameter $\Omega_q <0.1$ during big bang nucleosynthesis (BBN) requires $n<
1/6$. To overcome this drawback, we outline a few modifications where such
constraints can be weakened or relaxed. Finally, by establishing a
correspondence between the agegraphic dark energy scenario and the standard
scalar-field model, we also point out some interesting features of an
agegraphic quintessence model.


title: Optimal Sequential Frame Synchronization

abstract:
  We consider the `one-shot frame synchronization problem' where a decoder
wants to locate a sync pattern at the output of a channel on the basis of
sequential observations. We assume that the sync pattern of length N starts
being emitted at a random time within some interval of size A, that
characterizes the asynchronism level between the transmitter and the receiver.
We show that a sequential decoder can optimally locate the sync pattern, i.e.,
exactly, without delay, and with probability approaching one as N tends to
infinity, if and only if the asynchronism level grows as O(exp(N*k)), with k
below the `synchronization threshold,' a constant that admits a simple
expression depending on the channel. This constant is the same as the one that
characterizes the limit for reliable asynchronous communication, as was
recently reported by the authors. If k exceeds the synchronization threshold,
any decoder, sequential or non-sequential, locates the sync pattern with an
error that tends to one as N tends to infinity. Hence, a sequential decoder can
locate a sync pattern as well as the (non-sequential) maximum likelihood
decoder that operates on the basis of output sequences of maximum length A+N-1,
but with much fewer observations.


title: Isolating Triggered Star Formation

abstract:
  Galaxy pairs provide a potentially powerful means of studying triggered star
formation from galaxy interactions. We use a large cosmological N-body
simulation coupled with a well-tested semi-analytic substructure model to
demonstrate that the majority of galaxies in close pairs reside within cluster
or group-size halos and therefore represent a biased population, poorly suited
for direct comparison to ``field'' galaxies. Thus, the frequent observation
that some types of galaxies in pairs have redder colors than ``field'' galaxies
is primarily a selection effect. We select galaxy pairs that are isolated in
their dark matter halos with respect to other massive subhalos (N=2 halos) and
a control sample of isolated galaxies (N=1 halos) for comparison. We then apply
these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift
Survey with M_Bj <= -19 and obtain the first clean measure of the typical
fraction of galaxies affected by triggered star formation and the average
elevation in the star formation rate. We find that 24% (30.5%) of these L^\star
and sub-L^{\star} galaxies in isolated 50 (30) kpc/h pairs exhibit star
formation that is boosted by a factor of >~ 5 above their average past value,
while only 10% of isolated galaxies in the control sample show this level of
enhancement. Thus, 14% (20 %) of the galaxies in these close pairs show clear
triggered star formation. The isolation criteria we develop provide a means to
constrain star formation and feedback prescriptions in hydrodynamic simulations
and a very general method of understanding the importance of triggered star
formation in a cosmological context. (Abridged.)


title: Mapping Mass in the Local Universe

abstract:
  We only see a small fraction of the matter in the universe, but the rest
gives itself away by the impact of its gravity. Peculiar velocities have the
potential to be a powerful tool to trace this matter however previous peculiar
velocity surveys have struggled to meet their potential because of the large
errors on individual measurements, poor statistics and uneven sky coverage. The
2MASS Tully-Fisher (2MTF) survey will make use of existing high quality
rotations widths, new HI widths and 2MASS (2 Micron All-Sky Survey) photometry
to measure Tully-Fisher distances/peculiar velocities for all bright inclined
spirals in the 2MASS redshift survey (2MRS). This survey based on the 2MASS
galaxy catalog will provide a qualitatively better sample. It will provide
significant improvements in sky coverage especially near the plane of our
Galaxy which crosses the poorly understood "great attractor" region. I will
give a progress report on the 2MTF survey including a look at over 300 hours of
HI observations from the Green Bank Telescope (GBT) and a report on ongoing
southern hemisphere observations with the Parke s Radio Telescope. The new
spiral I-band field (SFI++) sample is currently the best available peculiar
velocity survey for use in the local universe. I will also report on some
preliminary results from this sample.


title:
The Coolest Stars in the Clouds: Unusual Red Supergiants in the
  Magellanic Clouds

abstract:
  Red supergiants (RSGs) are a He-burning phase in the evolution of moderately
high mass stars (10-25 solar masses). The evolution of these stars,
particularly at low metallicities, is still poorly understood. The latest-type
RSGs in the Magellanic Clouds are cooler than the current evolutionary tracks
allow, occupying the region to the right of the Hayashi limit where stars are
no longer in hydrodynamic equilibrium. We have discovered four Cloud RSGs in
this region that display remarkably similar unusual behavior. All of them show
considerable variations in their V magnitudes and effective temperatures (and
spectral types). Two of these stars, HV 11423 and [M2002] SMC 055188, have been
observed in an M4.5 I state, considerably later and cooler than any other
supergiant in the SMC. These stars suffer dramatic physical changes on
timescales of months - when they are at their warmest, they are also brighter,
more luminous, and show an increased amount of extinction. This variable
extinction is characteristic of the effects of circumstellar dust, and can be
connected with sporadic dust production from these stars in their cooler
states. We suggest that these unusual properties are indicative of an unstable
(and short-lived) evolutionary phase not previously associated with RSGs, and
consider the implications such behavior could have for our understanding of the
latest stages of massive star evolution in low-metallicity environments.


title:
Molecular Recognition Effects in the Surface Diffusion of Large Organic
  Molecules: The Case of Violet Lander

abstract:
  Violet Lander (VL) (C108H104) is a large organic molecule that when deposited
on Cu (110) exhibited lock-and-key like behavior (Otero et al., Nature Mater.
3, 779 (2004)). In this work we report on a detailed fully atomistic molecular
dynamics study of this phenomenon. Our results show that it has its physical
basis in the interplay of the molecular hydrogens and the Cu(110) atomic
spacing, which is a direct consequence of an accidental commensurability
between molecule and surface dimensions. This knowledge could be used to
engineer new molecules capable of displaying lock-and-key behavior with new
potential applications in nanotechology.


title: The Evolution of the Chemical elements of the Universe

abstract:
  Spectroscopic observations of distant cosmological sources continue to
exhibit a surprising result; that the chemical abundance of the universe seems
to be approximately solar for the observed sources at redshifts of 5, 6, and
even 7, even though very few galaxies should have existed at these epochs and
the principal star formation and heavy element production event should have
been at the more local z = 1 - 2.


title:
Rounding by disorder of first-order quantum phase transitions: emergence
  of quantum critical points

abstract:
  We give a heuristic argument for disorder rounding of a first order quantum
phase transition into a continuous phase transition. From both weak and strong
disorder analysis of the the N-color quantum Ashkin-Teller model in one spatial
dimension, we find that for $N \geq 3$, the first order transition is rounded
to a continuous transition and the physical picture is the same as the random
transverse field Ising model for a limited parameter regime. The results are
strikingly different from the corresponding classical problem in two dimensions
where the fate of the renormalization group flows is a fixed point
corresponding to N-decoupled pure Ising models.


title:
The spin axes orbital alignment of both stars within the eclipsing
  binary system V1143Cyg using the Rossiter-McLaughlin effect

abstract:
  Context: The Rossiter-McLaughlin (RM) effect, a rotational effect in
eclipsing systems, provides unique insight into the relative orientation of
stellar spin axes and orbital axes of eclipsing binary systems.
  Aims: Our aim is to develop a robust method to analyze the RM effect in an
eclipsing system with two nearly equally bright components. This gives access
to the orientation of the stellar rotation axes and may shed light on questions
of binary formation and evolution.
  Methods: High-resolution spectra have been obtained both out of eclipse and
during the primary and secondary eclipses in the V1143Cyg system, using the
high-resolution Hamilton Echelle Spectrograph at the Lick Observatory. The
Rossiter-McLaughlin effect is analyzed in two ways: (1) by measuring the shift
of the line center of gravity during different phases of the eclipses and (2)
by analysis of the line shape change of the rotational broadening function
during eclipses.
  Results: The projected axes of both stars are aligned with the orbital spin
within the observational uncertainties, with the angle of the primary rotation
axis beta_p=0.3+-1.5 deg, and the angle of the secondary rotation axis
beta_s=-1.2+-1.6 deg, thereby showing that the remaining difference between the
theoretical and observed apsidal motion for this system is not due to a
misalignment of the stellar rotation axes. Both methods utilized in this paper
work very well, even at times when the broadening profiles of the two stars
overlap.[abridged]


title:
Reaction-limited Colloidal Aggregation Induced by Salt and Inert
  Polymers

abstract:
  Salt-induced aggregation of 20 nm colloidal silica is followed by light
transmission, which shows an a kinetic form exp[-(t/t_0)^{\alpha}], where
\alpha = 2.6 and t_0 is an empirical time constant which reflects the colloidal
stability. We found a power law dependence of t_0 on ionic strength, which can
be explained by the classical DLVO theory. The neutral polymers polyethylene
glycol (PEG) accelerate the aggregation rate, and those with higher molecular
weight are more effective in inducing the aggregation with similar stretched
exponential form of kinetics. Current theories of polymer-mediated interactions
provide a reasonable interpretation of the effect of PEG. The stretched
exponential kinetics of the light transmission is found to be consistent with a
cluster-size dynamic scaling model of aggregation.


title: Single polaron properties of the breathing-mode Hamiltonian

abstract:
  We investigate numerically various properties of the one-dimensional (1D)
breathing-mode polaron. We use an extension of a variational scheme to compute
the energies and wave-functions of the two lowest-energy eigenstates for any
momentum, as well as a scheme to compute directly the polaron Greens function.
We contrast these results with results for the 1D Holstein polaron. In
particular, we find that the crossover from a large to a small polaron is
significantly sharper. Unlike for the Holstein model, at moderate and large
couplings the breathing-mode polaron dispersion has non-monotonic dependence on
the polaron momentum k. Neither of these aspects is revealed by a previous
study based on the self-consistent Born approximation.


title: On the DDVV Conjecture and the Comass in Calibrated Geometry (II)

abstract:
  In this paper, we proved P(n,3), which is an important part of the DDVV
conjecture. The general case will be treated in the next version of the paper.


title: Recombination fluorescence in ultracold neutral plasmas

abstract:
  We present the first measurements and simulations of recombination
fluorescence in ultracold neutral plasmas. In contrast with previous work,
experiment and simulation are in significant disagreement. Comparison with a
recombination model suggests that the disagreement could be due to the high
energy portion of the electron energy distribution or to large energy changes
in electron/Rydberg scattering. Recombination fluorescence opens a new
diagnostic window in ultracold plasmas because it probes the deeply-bound
Rydberg levels, which depend critically on electron energetics.


title:
Continuous opinion dynamics of multidimensional allocation problems
  under bounded confidence: More dimensions lead to better chances for
  consensus

abstract:
  We study multidimensional continuous opinion dynamics, where opinions are
nonnegative vectors which components sum up to one. Examples of such opinions
are budgets or other allocation vectors which display a distribution of a fixed
amount of ressource to n projects.
  We use the opinion dynamics models of Deffuant-Weisbuch and
Hegselmann-Krause, which both extend naturally to more dimensional opinions.
They both rely on bounded confidence of the agents and differ in their
communication regime. We show detailed simulation results regarding $n=2,...,8$
and the bound of confidence $\eps$. Number, location and size of opinion
clusters in the stabilized opinion profiles are of interest.
  Known differences of both models repeat under higher opinion dimensions:
Higher number of clusters and more minor clusters in the Deffuant-Weisbuch
model, meta-stable states in the Hegselmann-Krause model. But surprisingly,
higher dimensions lead to better chances for a vast majority consensus even for
lower bounds of confidence. On the other hand, the number of minority clusters
rises with n, too.


title:
Cuprate Fermi orbits and Fermi arcs: the effect of short-range
  antiferromagnetic order

abstract:
  We consider the effect of a short antiferromagnetic correlation length $\xi$
on the electronic bandstructure of the underdoped cuprates. Starting with a
Fermi-surface topology similar to that detected in magnetic quantum-oscillation
experiments, we show that a reduced $\xi$ gives an assymmetric broadening of
the quasiparticle dispersion, resulting in simulated ARPES data very similar to
those observed in experiment. Predicted features include the presence of `Fermi
arcs' close to $a{\bf k}=(\pi/2,\pi/2)$, without the need to invoke a d-wave
pseudogap order parameter. The statistical variation in the ${\bf k}$-space
areas of the reconstructed Fermi surface pockets causes the quantum
oscillations to be strongly damped, even in very strong magnetic fields, in
agreement with experiment.


title: Using Molecules to Measure Nuclear Spin-Dependent Parity Violation

abstract:
  Nuclear spin-dependent parity violation arises from weak interactions between
electrons and nucleons, and from nuclear anapole moments. We outline a method
to measure such effects, using a Stark-interference technique to determine the
mixing between opposite-parity rotational/hyperfine levels of ground-state
molecules. The technique is applicable to nuclei over a wide range of atomic
number, in diatomic species that are theoretically tractable for
interpretation. This should provide data on anapole moments of many nuclei, and
on previously unmeasured neutral weak couplings.


title:
Quantum and classical criticalities in the frustrated two-leg Heisenberg
  ladder

abstract:
  This talk was about the frustration-induced criticality in the
antiferromagnetic Heisenberg model on the two-leg ladder with exchange
interactions along the chains, rungs, and diagonals, and also about the effect
of thermal fluctuations on this criticlity. The method used is the bond
mean-field theory, which is based on the Jordan-Wigner transformation in
dimensions higher than one. In this paper, we will summarize the main results
presented in this talk, and report on new results about the couplings and
temperature dependences of the spin susceptibility.


title:
The VSL Discussion: What Does Variable Speed of Light Mean and Should we
  be Allowed to Think About ?

abstract:
  In the past years, variable speed of light (VSL) theories have been of
growing interest but also a subject of controversial discussion. They have been
accused both for tautologies and for violating special relativity, and concerns
have been expressed about the validity of such approaches in general (e.g.
Ellis, astro-ph/0703751). Without trying completeness on the issue, the example
of Einstein's VSL attempts (1911) and Dicke's `electromagnetic' theory (1957)
are urges to give some comments on the above criticism.


title:
The reciprocity law for the twisted second moment of Dirichlet
  L-functions

abstract:
  We produce a new proof of the reciprocity law for the twisted second moment
of Dirichlet L-functions that was recently proved by Conrey. Our method is to
analyze certain two-variable sums where the variables satisfy a linear
congruence. We show that these sums satisfy an elegant reciprocity formula. In
the case that the modulus is prime, these sums are closely related to the
twisted second moment, and the reciprocity formula for these sums implies
Conrey's reciprocity formula. We also extend the range of uniformity of
Conrey's formula.


title: On the origin of radio core emission in radio-quiet quasars

abstract:
  We present a model for the radio emission from radio-quiet quasar nuclei. We
show that a thermal origin for the high brightness temperature, flat spectrum
point sources (known as radio ``cores'') is possible provided the emitting
region is hot and optically-thin. We hence demonstrate that optically-thin
bremsstrahlung from a slow, dense disk wind can make a significant contribution
to the observed levels of radio core emission. This is a much more satisfactory
explanation, particularly for sources where there is no evidence of a jet, than
a sequence of self-absorbed synchrotron components which collectively conspire
to give a flat spectrum. Furthermore, such core phenomena are already observed
directly via milli-arcsecond radio imaging of the Galactic microquasar SS433
and the active galaxy NGC1068. We contend that radio-emitting disk winds must
be operating at some level in radio-loud quasars and radio galaxies as well
(although in these cases, observations of the radio cores are frequently
contaminated/dominated by synchrotron emission from jet knots). This
interpretation of radio core emission mandates mass accretion rates that are
substantially higher than Eddington. Moreover, acknowledgment of this mass-loss
mechanism as an AGN feedback process has important implications for the input
of energy and hot gas into the inter-galactic medium (IGM) since it is
considerably less directional than that from jets.


title:
Fluctuations and symmetry in the speed and direction of the jets of
  SS433 on different timescales

abstract:
  ABRIDGED We present new results on the variations in speed and direction of
the jet bolides in the Galactic microquasar SS433, from high resolution
spectra, taken with the ESO 3.6-m New Technology Telescope almost nightly over
0.4 of a precession cycle. We find: (i) These data exhibit multiple ejections
within most 24-hour periods and, throughout the duration of the observing
campaign, the weighted means of the individual bolides, in both the red jet and
the blue jet, clearly exhibit the pronounced nodding known in this system. (ii)
We present further evidence for a 13-day periodicity in the jet speed, and show
this cannot be dominated by Doppler shifts from orbital motion. (iii) We show
the phase of this peak jet speed has shifted by a quarter of a cycle in the
last quarter-century. (iv) We show that the two jets ejected by SS433 are
highly symmetric on timescales measured thus far. (v) We demonstrate that the
anti-correlation between variations in direction and in speed is not an
artifact of an assumption of symmetry. (vi) We show that a recently proposed
mechanism (Begelman et al 2006) for varying the ejection speed and
anti-correlating it with polar angle variations is ruled out. (vii) The speed
of expansion of the plasma bolides in the jets is approximately 0.0024c. These
novel data carry a clear signature of speed variations. They have a simple and
natural interpretation in terms of both angular and speed fluctuations which
are identical on average in the two jets. They complement archival optical data
and recent radio imaging.


title:
Structure-Activity Relationship Investigation of Some New Tetracyclines
  by Electronic Index Methodology

abstract:
  Tetracyclines are an old class of molecules that constitute a broad-spectrum
antibiotics. Since the first member of tetracycline family were isolated, the
clinical importance of these compounds as therapeutic and prophylactic agents
against a wide range of infections has stimulated efforts to define their mode
of action as inhibitors of bacterial reproduction. We used three SAR
methodologies for the analysis of biological activity of a set of 104
tetracycline compounds. Our calculation were carried out using the
semi-empirical Austin Method One (AM1) and Parametric Method 3 (PM3).
Electronic Indices Methodology (EIM), Principal Component Analysis (PCA) and
Artificial Neural Networks (ANN) were applied to the classification of 14 old
and 90 new proposed derivatives of tetracyclines. Our results make evident the
importance of EIM descriptors in pattern recognition and also show that the EIM
can be effectively used to predict the biological activity of Tetracyclines.


title:
Broken Pair Model: A viable Alterative to the Shell Model for
  Odd-Spherical Nuclei

abstract:
  The broken pair model has been developed earlier as an useful approximation
to the nuclear shell model for even-even nuclei. It is extended and developed
here to include odd nuclei too. The model is then applied successfully in the
Zr region, using two different sets of matrix elements, the empirical and the
realistic sussex ones. The broken pair model results show a considerable
agreement with the shell model results wherever available and with the
experimental data where shell model calculations are not performed yet.


title:
SUSY Shape-Invariant Hamiltonians for the Generalized Dirac-Coulomb
  Problem

abstract:
  A spin $\frac 12$ relativistic particle described by a general potential in
terms of the sum of the Coulomb potential with a Lorentz scalar potential is
investigated via supersymmetry in quantum mechanics.


title:
Observation of Galactic Sources of Very High Energy Gamma-Rays with the
  MAGIC Telescope

abstract:
  The MAGIC telescope with its 17m diameter mirror is today the largest
operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on
the Canary Island La Palma, at an altitude of 2200m above sea level, as part of
the Roque de los Muchachos European Northern Observatory. The MAGIC telescope
detects celestial very high energy gamma-radiation in the energy band between
about 50 GeV and 10 TeV. Since the autumn of 2004 MAGIC has been taking data
routinely, observing various objects, like supernova remnants (SNRs), gamma-ray
binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We
briefly describe the observational strategy, the procedure implemented for the
data analysis, and discuss the results of observations of Galactic Sources.


title:
Loss of entanglement in quantum mechanics due to the use of realistic
  measuring rods

abstract:
  We show that the use of real measuring rods in quantum mechanics places a
fundamental gravitational limit to the level of entanglement that one can
ultimately achieve in quantum systems. The result can be seen as a direct
consequence of the fundamental gravitational limitations in the measurements of
length and time in realistic physical systems. The effect may have implications
for long distance teleportation and the measurement problem in quantum
mechanics.


title: Priority Queue Based on Multilevel Prefix Tree

abstract:
  Tree structures are very often used data structures. Among ordered types of
trees there are many variants whose basic operations such as insert, delete,
search, delete-min are characterized by logarithmic time complexity. In the
article I am going to present the structure whose time complexity for each of
the above operations is $O(\frac{M}{K} + K)$, where M is the size of data type
and K is constant properly matching the size of data type. Properly matched K
will make the structure function as a very effective Priority Queue. The
structure size linearly depends on the number and size of elements. PTrie is a
clever combination of the idea of prefix tree -- Trie, structure of logarithmic
time complexity for insert and remove operations, doubly linked list and
queues.


title:
On the Connection of Anisotropic Conductivity to Tip Induced Space
  Charge Layers in Scanning Tunneling Spectroscopy of p-doped GaAs

abstract:
  The electronic properties of shallow acceptors in p-doped GaAs{110} are
investigated with scanning tunneling microscopy at low temperature. Shallow
acceptors are known to exhibit distinct triangular contrasts in STM images for
certain bias voltages. Spatially resolved I(V)-spectroscopy is performed to
identify their energetic origin and behavior. A crucial parameter - the STM
tip's work function - is determined experimentally. The voltage dependent
potential configuration and band bending situation is derived. Ways to validate
the calculations with the experiment are discussed. Differential conductivity
maps reveal that the triangular contrasts are only observed with a depletion
layer present under the STM tip. The tunnel process leading to the anisotropic
contrasts calls for electrons to tunnel through vacuum gap and a finite region
in the semiconductor.


title: Neck Pinching Dynamics Under Mean Curvature Flow

abstract:
  In this paper we study motion of surfaces of revolution under the mean
curvature flow. For an open set of initial conditions close to cylindrical
surfaces we show that the solution forms a "neck" which pinches in a finite
time at a single point. We also obtain a detailed description of the neck
pinching process.


title:
Observing the Dark Scalar Doublet and its Impact on the Standard-Model
  Higgs Boson at Colliders

abstract:
  If the Standard Model of particle interactions is extended to include a
second scalar doublet $[H^{+},(H^{0}+iA^{0})/\sqrt{2}]$, which is odd under an
unbroken Z_{2} discrete symmetry, it may be called the $dark$ scalar doublet,
because its lightest neutral member, say H^{0}, is one posssible component for
the dark matter of the Universe. We discuss the general phenomenology of the
four particles of this doublet, without assuming that H^{0} is the dominant
source of dark matter. We also consider the impact of this $dark$ scalar
doublet on the phenomenology of the SM Higgs boson h.


title:
Nonequilibrium steady state thermodynamics and fluctuations for
  stochastic systems

abstract:
  We use the work done on and the heat removed from a system to maintain it in
a nonequilibrium steady state for a thermodynamic-like description of such a
system as well as of its fluctuations. Based on a generalized Onsager-Machlup
theory for nonequilibrium steady states we indicate two ambiguities, not
present in an equilibrium state, in defining such work and heat: one due to a
non-uniqueness of time-reversal procedures and another due to multiple
possibilities to separate heat into work and an energy difference in
nonequilibrium steady states. As a consequence, for such systems, the work and
heat satisfy multiple versions of the first and second laws of thermodynamics
as well as of their fluctuation theorems. Unique laws and relations appear only
to be obtainable for concretely defined systems, using physical arguments to
choose the relevant physical quantities. This is illustrated on a number of
systems, including a Brownian particle in an electric field, a driven torsion
pendulum, electric circuits and an energy transfer driven by a temperature
difference.


title: Hook modules for general linear groups

abstract:
  For an arbitrary infinite field k of characteristic p > 0, we describe the
structure of a block of the algebraic monoid M_n(k) (all n x n matrices over
k), or, equivalently, a block of the Schur algebra S(n,p), whose simple modules
are indexed by p-hook partitions. The result is known; we give an elementary
and self-contained proof, based only on a result of Peel and Donkin's
description of the blocks of Schur algebras. The result leads to a character
formula for certain simple GL_n(k)-modules, valid for all n and all p. This
character formula is a special case of one found by Brundan, Kleshchev, and
Suprunenko and, independently, by Mathieu and Papadopoulo.


title:
A Comprehensive Analysis of Swift/XRT Data: III. Jet Break Candidates in
  X-ray and Optical Afterglow Lightcurves

abstract:
  The Swift/XRT data of 179 GRBs (from 050124 to 070129) and the optical
afterglow data of 57 pre- and post-Swift GRBs are analyzed, in order to
systematically investigate the jet-like breaks in the X-ray and optical
afterglow lightcurves. We find that not a single burst can be included in the
``Platinum'' sample, in which the data satisfy all the criteria of a jet break.
By releasing one or more requirements to define a jet break, some candidates of
various degrees could be identified. In the X-ray band, 42 out of the 103
well-sampled X-ray lightcurves have a decay slope of the post-break segment
>1.5 (``Bronze'' sample), and 27 of them also satisfy the closure relations of
the forward models (``Silver'' sample). The numbers of the ``Bronze'' and
``Silver'' candidates in the optical lightcurves are 27 and 23, respectively.
Thirteen bursts have well-sampled optical and X-ray lightcurves, but only seven
cases are consistent with an achromatic break, but even in these cases only one
band satisfies the closure relations (``Gold'' sample). The observed break time
in the XRT lightcurves is systematically earlier than that in the optical
bands. All these raise great concerns in interpreting the jet-like breaks as
jet breaks and further inferring GRB energetics from these breaks. By assuming
that these breaks are jet breaks, we perform a similar analysis as previous
work to calculate the jet opening angle (theta_j) and energetics (E_k) with the
``Silver'' and ``Gold'' jet break candidates. The derived E_K distribution
reveals a much larger scatter than the pre-Swift sample. A tentative
anti-correlation between theta_j and E_{K,iso} is found for both the pre-Swift
and Swift GRBs, indicating that the E_K could still be quasi-universal, if the
breaks in discussion are indeed jet breaks(abridge).


title:
Dark Energy or Apparent Acceleration Due to a Relativistic Cosmological
  Model More Complex than FLRW?

abstract:
  We use the Szekeres inhomogeneous relativistic models in order to fit
supernova combined data sets. We show that with a choice of the spatial
curvature function that is guided by current observations, the models fit the
supernova data almost as well as the LCDM model without requiring a dark energy
component. The Szekeres models were originally derived as an exact solution to
Einstein's equations with a general metric that has no symmetries and are
regarded as good candidates to model the true lumpy universe that we observe.
The null geodesics in these models are not radial. The best fit model found is
also consistent with the requirement of spatial flatness at CMB scales. The
first results presented here seem to encourage further investigations of
apparent acceleration using various inhomogeneous models and other constraints
from CMB and large structure need to be explored next.


title: The K-Theory of Toeplitz C*-Algebras of Right-Angled Artin Groups

abstract:
  To a graph $\Gamma$ one can associate a C^*-algebra $C^*(\Gamma)$ generated
by isometries. Such $C^*$-algebras were studied recently by Crisp and Laca.
They are a special case of the Toeplitz C^*-algebras $\mathcal{T}(G, P)$
associated to quasi-latice ordered groups (G, P) introduced by Nica. Crisp and
Laca proved that the so called "boundary quotients" $C^*_q(\Gamma)$ of
$C^*(\Gamma)$ are simple and purely infinite. For a certain class of finite
graphs $\Gamma$ we show that $C^*_q(\Gamma)$ can be represented as a full
corner of a crossed product of an appropriate C^*-subalgebra of $C^*_q(\Gamma)$
built by using $C^*(\Gamma')$, where $\Gamma'$ is a subgraph of $\Gamma$ with
one less vertex, by the group $\mathbb{Z}$. Using induction on the number of
the vertices of $\Gamma$ we show that $C^*_q(\Gamma)$ are nuclear and belong to
the small bootstrap class. This also enables us to use the Pimsner-Voiculescu
exact sequence to find their K-theory. Finally we use the Kirchberg-Phillips
classification theorem to show that those C^*-algebras are isomorphic to tensor
products of $\mathcal{O}_n$ for $1 \leq n \leq \infty$.


title:
Tackling the Fermionic Sign Problem in the Auxiliary-Field Monte Carlo
  Method

abstract:
  We explore a novel and straightforward solution to the sign problem that has
plagued the Auxiliary-field Monte Carlo (AFMC) method applied to many-body
systems for more than a decade. We present a solution to the sign problem that
has plagued the Auxiliary-field Monte Carlo (AFMC) method for more than a
decade and report a breakthrough where excellent agreement between AFMC and
exact CI calculations for fully realistic nuclear applications is achieved.
This result offers the capability, unmatched by other methods, to achieve exact
solutions for large-scale quantum many-body systems.


title:
The number of gauge singlets in supersymmetric Yang-Mills quantum
  mechanics

abstract:
  We compute generating functions for number of U(N) (SU(N)) singlets in Fock
space in several space dimensions. The motivation to find the explicit form of
the functions is from the numerical approach to supersymmetric Yang-Mills
quantum mechanics, based on Fock space. Incidently the functions give many
important insights into the quantum mechanical models based U(N) (SU(N)) gauge
group.


title: Detection of high-energy gamma rays from winter thunderclouds

abstract:
  A report is made on a comprehensive observation of a burst-like $\gamma$-ray
emission from thunderclouds on the Sea of Japan, during strong thunderstorms on
2007 January 6. The detected emission, lasting for $\sim$40 seconds, preceded
cloud-to-ground lightning discharges. The burst spectrum, extending to 10 MeV,
can be interpreted as consisting of bremsstrahlung photons originating from
relativistic electrons. This ground-based observation provides first clear
evidence that strong electric fields in thunderclouds can continuously
accelerate electrons beyond 10 MeV prior to lightning discharges.


title: Energy of knots and the infinitesimal cross ratio

abstract:
  This is a survey article on two topics. The Energy E of knots can be obtained
by generalizing an electrostatic energy of charged knots in order to produce
optimal knots. It turns out to be invariant under Moebius transformations. We
show that it can be expressed in terms of the infinitesimal cross ratio, which
is a conformal invariant of a pair of 1-jets, and give two kinds of
interpretations of the real part of the infinitesimal cross ratio.


title:
Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic
  Mechanisms?

abstract:
  It is known that there must be some weak form of transport (called cool
bottom processing, or CBP) acting in low mass RGB and AGB stars, adding nuclei,
newly produced near the hydrogen-burning shell, to the convective envelope. We
assume that this extra-mixing originates in a stellar dynamo operated by the
differential rotation below the envelope, maintaining toroidal magnetic fields
near the hydrogen-burning shell. We use a phenomenological approach to the
buoyancy of magnetic flux tubes, assuming that they induce matter circulation
as needed by CBP models. This establishes requirements on the fields necessary
to transport material from zones where some nuclear burning takes place,
through the radiative layer, and into the convective envelope. Magnetic field
strengths are determined by the transport rates needed by CBP for the model
stellar structure of a star of initially 1.5 solar mass, in both the AGB and
RGB phases. The field required for the AGB star in the processing zone is B_0 ~
5x10^6 G; at the base of the convective envelope this yields an intensity B_E <
10^4 G (approximately). For the RGB case, B_0 ~ 5x10^4 to 4x10^5 G, and the
corresponding B_E are ~ 450 to 3500 G. These results are consistent with
existing observations on AGB stars. They also hint at the basis for high field
sources in some planetary nebulae and the very large fields found in some white
dwarfs. It is concluded that transport by magnetic buoyancy should be
considered as a possible mechanism for extra mixing through the radiative zone,
as is required by both stellar observations and the extensive isotopic data on
circumstellar condensates found in meteorites.


title: The D^4 R^4 term in type IIB string theory on T^2 and U-duality

abstract:
  We propose a manifestly U-duality invariant modular form for the D^4 R^4
interaction in type IIB string theory compactified on T^2. It receives
perturbative contributions upto two loops, and non-perturbative contributions
from D-instantons and (p,q) string instantons wrapping T^2. We provide evidence
for this modular form by showing that the coefficients at tree level and at one
loop precisely match those obtained using string perturbation theory. Using
duality, parts of the perturbative amplitude are also shown to match exactly
the results obtained from eleven dimensional supergravity compactified on T^3
at one loop. Decompactifying the theory to nine dimensions, we obtain a
U-duality invariant modular form, whose coefficients at tree level and at one
loop agree with string perturbation theory.


title:
QCD corrections to t\bar t b \bar b productions via photon-photon
  collisions at linear colliders

abstract:
  We calculated the complete next-to-leading order(NLO) QCD corrections to the
$t\bar t b \bar b$ production process at a $\gamma \gamma$ collider in the
standard model(SM). The calculation of the one-loop QCD correction includes the
evaluations of the hexagon and pentagon amplitudes. We studied the NLO QCD
corrected total cross section, the distributions of transverse momenta of final
top- and bottom-quark states, and the dependence of the cross section on
renormalization scale $\mu$. It shows that NLO QCD correction generally
increases the LO cross section in our chosen parameter space, and the K-factor
varies from 1.70 to 1.14 when colliding energy goes up from $400 GeV$ to $2
TeV$. We find that the correction distinctly changes the distributions of
transverse momenta of the final top- and bottom-quark states, and the NLO QCD
correction obviously improves the independence of the cross section for process
$\gamma\gamma \to t\bar t b\bar b$ on the renormalization scale.


title:
QED of excitons with nonlocal susceptibility in arbitrary-structured
  dielectrics

abstract:
  We have constructed a complete quantum theory for an optical process of
excitons with nonlocal susceptibility originating from their center-of-mass
motion. This theory provides a practical calculation method for
arbitrary-structured nano-to-macro scale dielectrics where excitons are weakly
confined. We obtain good correspondences with underlying theories,
semiclassical microscopic nonlocal theory, and QED theories for dispersive and
absorptive materials with local susceptibility.


title:
Equilibrium-like behavior in far-from-equilibrium chemical reaction
  networks

abstract:
  In an equilibrium chemical reaction mixture, the number of molecules present
obeys a Poisson distribution. We ask when the same is true of the steady state
of a nonequilibrium reaction network and obtain an essentially complete answer.
In particular, we show that networks with certain topological features must
have a Poisson distribution, whatever the reaction rates. Such driven systems
also obey an analog of the fluctuation-dissipation theorem. Our results may be
relevant to biological systems and to the larger question of how equilibrium
concepts might apply to nonequilibrium systems.


title: Coronal Neutrino Emission in Hypercritical Accretion Flows

abstract:
  Hypercritical accretion flows onto stellar mass black holes (BHs) are
commonly considered as a promising model of central engines of gamma-ray bursts
(GRBs). In this model a certain fraction of gravitational binding energy of
accreting matter is deposited to the energy of relativistic jets via neutrino
annihilation and/or magnetic fields. However, some recent studies have
indicated that the energy deposition rate by neutrino annihilation is somewhat
smaller than that needed to power a GRB. To overcome this difficulty,
Ramirez-Ruiz & Socrates (2005) proposed that high energy neutrinos from hot
corona above the accretion disk might enhance the efficiency of energy
deposition. We elucidate the disk corona model in the context of hypercritical
accretion flows. From the energy balance in the disk and the corona, we can
calculate the disk and coronal temperature, Td and Tc, and neutrino spectra,
taking into account the neutrino cooling processes by neutrino-electron
scatterings and neutrino pair productions. The calculated neutrino spectra
consist of two peaks; one by the neutrino emission from the disk and the other
by that from the corona. We find that the disk corona can enhance the
efficiency of energy release but only by a factor of 1.5 or so, unless the
height of the corona is very small, H<<r. This is because the neutrino emission
is very sensitive to the temperature of emitting region, and then the ratio
Tc/Td cannot be so large.


title: Gamma-ray emission from massive young stellar objects

abstract:
  Massive stars form in dense and massive molecular cores. The exact formation
mechanism is unclear, but it is possible that some massive stars are formed by
processes similar to those that produce the low-mass stars, with
accretion/ejection phenomena occurring at some point of the evolution of the
protostar. This picture seems to be supported by the detection of a collimated
stellar wind emanating from the massive protostar IRAS 16547-4247. A triple
radio source is associated with the protostar: a compact core and two radio
lobes. The emission of the southern lobe is clearly non-thermal. Such emission
is interpreted as synchrotron radiation produced by relativistic electrons
locally accelerated at the termination point of a thermal jet. Since the
ambient medium is determined by the properties of the molecular cloud in which
the whole system is embedded, we can expect high densities of particles and
infrared photons. Because of the confirmed presence of relativistic electrons,
inverse Compton and relativistic Bremsstrahlung interactions are unavoidable.
Proton-proton collision should also occur, producing an injection of neutral
pions. In this paper we aim at making quantitative predictions of the spectral
energy distribution of the non-thermal spots generated by massive young stellar
objects, with emphasis on the particular case of IRAS 16547-4247. We present
spectral energy distributions for the southern lobe of this source, for a
variety of conditions. We show that high-energy emission might be detectable
from this object in the gamma-ray domain (MeV to TeV). The source may also be
detectable at X-rays through long exposures with current X-ray instruments.


title:
At Least Half Of All Graphs Satisfy \chi \leq {1/4}\omega + {3/4}\Delta
  + 1

abstract:
  We prove that for any graph G at least one of G or $\bar{G}$ satisfies $\chi
\leq {1/4}\omega + {3/4}\Delta + 1$. In particular, self-complementary graphs
satisfy this bound.


title:
A quantization of the Hitchin hamiltonian system and the
  Beilinson-Drinfeld isomorphism

abstract:
  We will study the Hitchin's hamiltonian system for a modular stack of
principal SL_2(C) bundle on a smooth projective curve which has a parabolic
reduction at certain points. As an application we will obtain a generalization
of the Beilinson-Drinfeld isomorphism, which is a quantization of the Hitchin's
hamiltonian system.


title:
Quantum critical phenomena of unconventional superconductors: U(1) gauge
  model of link Cooper pair

abstract:
  In this paper we shall study quantum critical behavior of lattice model of
unconventional superconductors (SC) that was proposed in the previous papers.
In this model, the Cooper-pair (CP) field is defined on lattice links in order
to describe d-wave SC. The CP field can be regarded as a U(1) lattice gauge
field, and the SC phase transition takes place as a result of the phase
coherence of the CP field. Effects of the long-range Coulomb interactions
between the CP's and fluctuations of the electromagnetic field are taken into
account. We investigate the phase structure of the model and the critical
behavior by means of the Monte Carlo simulations. We find that the parameter,
which controls the fluxes (vortices) of the CP, strongly influences the phase
structure. In three-dimensional case, the model has rich phase structure. In
particular there is a "monopole proliferation" phase transition besides the SC
phase transition. Depending on the parameters, this transition exists within
the SC phase or takes place simultaneously with the SC transition. This new
type of transition is relevant for unconventional SC's with strong spatial
three-dimensionality and to be observed by experiments.


title: Molecular Line Observations of the Small Protostellar Group L1251B

abstract:
  We present molecular line observations of L1251B, a small group of pre- and
protostellar objects, and its immediate environment in the dense C18O core
L1251E. These data are complementary to near-infrared, submillimeter and
millimeter continuum observations reported by Lee et al. (2006, ApJ, 648, 491;
Paper I). The single-dish data of L1251B described here show very complex
kinematics including infall, rotation and outflow motions, and the
interferometer data reveal these in greater detail. Interferometer data of N2H+
1-0 suggest a very rapidly rotating flattened envelope between two young
stellar objects, IRS1 and IRS2. Also, interferometer data of CO 2-1 resolve the
outflow associated with L1251B seen in single-dish maps into a few narrow and
compact components. Furthermore, the high resolution data support recent
theoretical studies of molecular depletions and enhancements that accompany the
formation of protostars within dense cores. Beyond L1251B, single-dish data are
also presented of a dense core located ~150" to the east that, in Paper I, was
detected at 850 micron but has no associated point sources at near- and
mid-infrared wavelengths. The relative brightness between molecules, which have
different chemical timescales, suggests it is less chemically evolved than
L1251B. This core may be a site for future star formation, however, since line
profiles of HCO+, CS, and HCN show asymmetry with a stronger blue peak, which
is interpreted as an infall signature.


title: Rational Solutions of the Noumi and Yamada System of type $A_5^{(1)}$

abstract:
  We completely classify all of rational solutions of the Noumi and Yamada
system of type $A_5^{(1)}$, which is a generalization of the fifth Painlev\'e
equation. The rational solutions are classified to five classes by the
B\"acklund transformation group.


title: Cancellation problem for projective modules over affine algebras

abstract:
  Let A be a ring of dimension d and let P be a projective A-module of rank d.
We prove that if for every finite extension R of A, R^d is cancellative, then P
is cancellative. This gives an alternate proof of Bhatwadekar's result: every
projective module of rank d over an affine algebra of dimension d over a
C_1-field of characteristic 0 is cancellative.
  Let P be a projective module of rank d-1 over an affine agebra of dimension d
over an algebraically closed field. Then, it is not known if P is cancellative.
We prove some results in this direction also.