title: Gauge theory in deformed N=(1,1) superspace

abstract:
  We review the non-anticommutative Q-deformations of N=(1,1) supersymmetric
theories in four-dimensional Euclidean harmonic superspace. These deformations
preserve chirality and harmonic Grassmann analyticity. The associated field
theories arise as a low-energy limit of string theory in specific backgrounds
and generalize the Moyal-deformed supersymmetric field theories. A
characteristic feature of the Q-deformed theories is the half-breaking of
supersymmetry in the chiral sector of the Euclidean superspace. Our main focus
is on the chiral singlet Q-deformation, which is distinguished by preserving
the SO(4) Spin(4) ``Lorentz'' symmetry and the SU(2) R-symmetry. We present the
superfield and component structures of the deformed N=(1,0) supersymmetric
gauge theory as well as of hypermultiplets coupled to a gauge superfield:
invariant actions, deformed transformation rules, and so on. We discuss quantum
aspects of these models and prove their renormalizability in the abelian case.
For the charged hypermultiplet in an abelian gauge superfield background we
construct the deformed holomorphic effective action.


title: Pairing Symmetry of CeCoIn$_5$ Detected by In-plane Torque Measurements

abstract:
  In-plane torque measurements were performed on heavy fermion CeCoIn$_5$
single crystals in the temperature $T$ range 1.8 K $\leq T \leq 10$ K and
applied magnetic field $H$ up to 14 T. The normal-state torque is given by
$\tau_n \propto H^4(1+T/T_K)^{-1}\sin 4\phi$. The reversible part of the
mixed-state torque, obtained after subtracting the corresponding normal state
torque, shows also a four-fold symmetry. In addition, sharp peaks are present
in the irreversible torque at angles of $\pi/$4, 3$\pi$/4, 5$\pi$/4, 7$\pi$/4,
etc. Both the four-fold symmetry in the reversible torque and the sharp peaks
in the irreversible torque of the mixed state imply $d_{xy}$ symmetry of the
superconducting order parameter. The field and temperature dependences of the
reversible mixed-state torque provide further evidence for $d_{xy}$ wave
symmetry. The four-fold symmetry in the normal state has a different origin
since it has different field and temperature dependences than the one in the
mixed state. The possible reasons of the normal state four-fold symmetry are
discussed.


title:
Star formation in accretion discs : from the Galactic Center to Active
  Galactic Nuclei

abstract:
  Keplerian accretion discs around massive black holes (MBHs) are
gravitationally unstable beyond a few hundredths of parsec and should collapse
to form stars. Indeed an accretion/star formation episode took place a few
millions years ago in the Galactic Center (GC). This raises the question of how
the disc can survive in AGN and quasars and continue to transport matter
towards the black hole. We study the accretion/star formation process, with one
aim in mind, to show that a spectrum similar to the observed AGN one can be
produced by the disc. We compute models of stationary accretion discs, both
continuous and clumpy. Continuous discs must be maintained in a state of
marginal stability for the rate of star formation to remain modest, so they
require additional heating and transport of angular momentum. Non-viscous
heating can be provided by stellar illumination, but momentum transport by
supernovae is insufficient to sustain a marginal state, except at the very
periphery of the disc. In clumpy discs it is possible to account for the
required accretion rate through interactions between clouds, but this model is
unsatisfactory as its parameters are tightly constrained without any physical
justification. Finally one must appeal to non-stationary discs with
intermittent accretion episodes like those that occurred in the GC, but such a
model is probably not applicable to luminous high redshift quasars neither to
radio-loud quasars.


title: Transient neutron star X-ray binaries with Simbol-X

abstract:
  We present a brief overview of test-bed observations on accreting neutron
star binaries for the Simbol-X mission. We show that Simbol-X will provide
unique observations able to disclose the physical mechanisms responsible for
their high energy emission.


title: Absorbing-state phase transitions: exact solutions of small systems

abstract:
  I derive precise results for absorbing-state phase transitions using exact
(numerically determined) quasistationary probability distributions for small
systems. Analysis of the contact process on rings of 23 or fewer sites yields
critical properties (control parameter, order-parameter ratios, and critical
exponents z and beta/nu_perp) with an accuracy of better than 0.1%; for the
exponent nu_perp the accuracy is about 0.5%. Good results are also obtained for
the pair contact process.


title:
Lower limit on the achievable temperature in resonator-based sideband
  cooling

abstract:
  A resonator can be effectively used as a cooler for another linear oscillator
with a much smaller frequency. A huge cooling effect, which could be used to
cool a mechanical oscillator below the energy of quantum fluctuations, has been
predicted by several authors. However, here we show that there is a lower limit
T* on the achievable temperature that was not considered in previous works and
can be higher than the quantum limit in realistic experimental realizations. We
also point out that the decay rate of the resonator, which previous studies
stress should be small, must be larger than the decay rate of the cooled
oscillator for effective cooling.


title:
Millimeter wave spectral line surveys and line mapping studies of
  NGC6334I and I(N)

abstract:
  NGC6334I and I(N) have been observed with the Swedish-ESO Submillimetre
Telescope, SEST, at wavelengths of 3, 2, and 1.3 mm. Especially NGC6334 I shows
rich emission from many different molecules, comparable in line density to
prototypical hot cores such as Orion-KL and SgrB2(N). In addition, a 4' by 4'
region enfolding NGC 6334 I and I(N) has been mapped at a wavelength of 3 mm
(75 to 116 GHz) with the Mopra telescope.


title:
Muon spin rotation study of the ternary noncentrosymmetric
  superconductors Li$_2$Pd$_x$Pt$_{3-x}$B

abstract:
  We investigated the superconducting state of the noncentrosymmetric
superconductors Li$_2$Pd$_x$Pt$_{3-x}$B with superconducting transition
temperature $T_c$= 5.16(8) K ($x$=2.25), 3.56(8) K ($x=1.5$) and 2.60 K ($x=0$)
by means of muon-spin rotation ($\mu$SR) and specific heat experiments. The
$\mu$SR relaxation rate $\sigma_{sc}$ was found to be constant at low
temperatures for all the compounds. Data taken at different magnetic fields
show that the magnetic penetration depth $\lambda$ is field-independent for
Li$_2$Pd$_{2.25}$Pt$_{0.75}$B and Li$_2$Pt$_{3}$B. The electronic contribution
to the specific heat measured in Li$_2$Pd$_{1.5}$Pt$_{1.5}$B and
Li$_2$Pt$_{3}$B increases exponentially at the lowest temperatures. These
features suggest that the {\it whole family} of Li$_2$Pd$_x$Pt$_{3-x}$B are
single-gap s-wave superconductors across the entire doping regime.


title: On Deformations of Pasting Diagrams

abstract:
  We adapt the work of Power to describe general, not-necessarily composable,
not-necessarily commutative 2-categorical pasting diagrams and their composable
and commutative parts. We provide a deformation theory for pasting diagrams
valued in $k$-linear categories, paralleling that provided for diagrams of
algebras by Gerstenhaber and Schack, proving the standard results. Along the
way, the construction gives rise to a bicategorical analog of the homotopy
G-algebras of Gerstenhaber and Voronov.


title:
A general scheme for construction of scalar separability criteria from
  positive maps

abstract:
  We present a general scheme that allows for construction of scalar
separability criteria from positive but not completely positive maps. The
concept is based on a decomposition of every positive map $\Lambda$ into a
difference of two completely positive maps $\Lambda_1$, $\Lambda_2$, i.e.,
$\Lambda=\Lambda_1-\Lambda_2$. The scheme may be also treated as a
generalization of the known entropic inequalities, which are obtained from the
reduction map. An analysis performed on few classes of states shows that the
new scalar criteria are stronger than the entropic inequalities and
furthermore, when derived from indecomposable maps allow for detection of bound
entanglement.


title:
Order parameter for the dynamical phase transition in Bose-Einstein
  condensates with topological modes

abstract:
  In a trapped Bose-Einstein condensate, subject to the action of an
alternating external field, coherent topological modes can be resonantly
excited. Depending on the amplitude of the external field and detuning
parameter, there are two principally different regimes of motion, with mode
locking and without it. The change of the dynamic regime corresponds to a
dynamic phase transition. This transition can be characterized by an effective
order parameter defined as the difference between fractional mode populations
averaged over the temporal period of oscillations. The behavior of this order
parameter, as a function of detuning, pumping amplitude, and atomic
interactions is carefully analyzed. A special attention is payed to numerical
calculations for the realistic case of a quadrupole exciting field and the
system parameters accessible in current experiments.


title:
Star cluster "infant mortality" in the Small Magellanic Cloud
  (Redivivus)

abstract:
  The early evolution of star clusters in the Small Magellanic Cloud (SMC) has
been the subject of significant recent controversy, particularly regarding the
importance and length of the earliest, largely mass-independent disruption
phase (referred to as "infant mortality"). Here, we take a fresh approach to
the problem, using an independent, homogeneous data set of UBVR imaging
observations, from which we obtain the SMC's cluster age and mass distributions
in a self-consistent manner. We conclude that the (optically selected) SMC star
cluster population has undergone at most ~30 per cent (1 sigma) infant
mortality between the age range from about (3-10) Myr, to that of approximately
(40-160) Myr. We rule out a 90 per cent cluster mortality rate per decade of
age (for the full age range up to 10^9 yr) at a > 6 sigma level. We
independently affirm this scenario based on the age distribution of the SMC
cluster sample.


title: Aharonov-Bohm interactions of a vector unparticle

abstract:
  Recently Georgi argued that hypothetical conformally invariant hidden sector
weakly interacting with ordinary particles will have unusual manifestations at
low energies in terms of effective degrees of freedom called unparticles. In
this note we consider Aharonov-Bohm type of interactions due to the vector
unparticle coupled to elementary fermions. We have found that quantum
mechanical phase shift is path-dependent.


title:
Measurement of Absolute Hadronic Branching Fractions of D Mesons and e^+
  e^- --> D D-bar Cross Sections at the psi(3770)

abstract:
  Using 281 /pb of e^+ e^- collisions recorded at the psi(3770) resonance with
the CLEO-c detector at CESR, we determine absolute hadronic branching fractions
of charged and neutral D mesons using a double tag technique. Among
measurements for three D^0 and six D^+ modes, we obtain reference branching
fractions B(D^0 --> K^-pi^+) = (3.891 +- 0.035 +- 0.059 +- 0.035)% and B(D^+
--> K^-pi^+pi^+) = (9.14 +- 0.10 +- 0.16 +- 0.07)%, where the first uncertainty
is statistical, the second is all systematic errors other than final state
radiation (FSR), and the third is the systematic uncertainty due to FSR. We
include FSR in these branching fractions by allowing for additional unobserved
photons in the final state. Using an independent determination of the
integrated luminosity, we also extract the cross sections sigma(e+e- --> D^0
D^0-bar) = (3.66+- 0.03 +- 0.06) nb and sigma(e+e- --> D^+ D^-) = (2.91+- 0.03
+- 0.05) nb at a center of mass energy, E_cm = 3774 +- 1 MeV.


title: A Field of Generalised Puiseux Series for Tropical Geometry

abstract:
  In this paper we define a field K of characteristic zero with valuation whose
value group is the real numbers, and we show that this field of generalised
Puiseux series is algebraically closed and complete with respect to the norm
induced by its valuation. We consider this field to be a good candidate for the
base field for tropical geometry.


title: The j-invariant of a plane tropical cubic

abstract:
  Several results in tropical geometry have related the j-invariant of an
algebraic plane curve of genus one to the cycle length of a tropical curve of
genus one. In this paper, we prove that for a plane cubic over the field of
Puiseux series the negative of the generic valuation of the $j$-invariant is
equal to the cycle length of the tropicalization of the curve, if there is a
cycle at all.


title: Geometric incidence theorems via Fourier analysis

abstract:
  We prove that non-trivial bounds for generalized Radon transforms imply
correspondingly non-trivial discrete incidence theorems for manifolds and
suitably regular point sets.


title:
Rabi-like oscillations of an anharmonic oscillator: classical versus
  quantum interpretation

abstract:
  We have observed Rabi-like oscillations in a current-biased dc SQUID
presenting enhanced coherence times compared to our previous realization
\cite{Claudon_PRL04}. This Josephson device behaves as an anharmonic oscillator
which can be driven into a coherent superposition of quantum states by resonant
microwave flux pulses. Increasing the microwave amplitude, we study the
evolution of the Rabi frequency from the 2-level regime to the regime of
multilevel dynamics. When up to 3 levels are involved, the Rabi frequency is a
clear signature of quantum behavior. At higher excitation amplitude, classical
and quantum predictions for the Rabi frequency converge. This result is
discussed in the light of a calculation of the Wigner function. In particular,
our analysis shows that pronounced quantum interferences always appear in the
course of the Rabi-like oscillations.


title:
On the path structure of a semimartingale arising from monotone
  probability theory

abstract:
  Let $X$ be the unique normal martingale such that $X_0=0$ and
\[\mathrm{d}[X]_t=(1-t-X_{t-}) \mathrm{d}X_t+\mathrm{d}t\] and let $Y_t:=X_t+t$
for all $t\geq 0$; the semimartingale $Y$ arises in quantum probability, where
it is the monotone-independent analogue of the Poisson process. The
trajectories of $Y$ are examined and various probabilistic properties are
derived; in particular, the level set $\{t\geq 0\dvt Y_t=1\}$ is shown to be
non-empty, compact, perfect and of zero Lebesgue measure. The local times of
$Y$ are found to be trivial except for that at level 1; consequently, the jumps
of $Y$ are not locally summable.


title:
Using GRO J1655-40 to test Swift/BAT as a monitor for bright hard X-ray
  sources

abstract:
  While waiting for new gamma-ray burst detections, the Burst Alert Telescope
(BAT) on board Swift covers each day ~50% of the sky in the hard X-ray band
(``Survey data''). The large field of view (FOV), high sensitivity and good
angular resolution make BAT a potentially powerful all-sky hard X-ray monitor,
provided that mask--related systematics can be properly accounted for. We have
developed and tested a complete procedure entirely based on public Swift/BAT
software tools to analyse BAT Survey data, aimed at assessing the flux and
spectral variability of bright sources in the 15-150 keV energy range. Detailed
tests of the capabilities of our procedure were performed focusing, in
particular, on the reliability of spectral measurements over the entire BAT
FOV. First, we analyzed a large set of Crab observations, spread over ~7
months. Next, we studied the case of GRO J1655-40, a strongly variable source,
which experienced a 9-month long outburst, beginning on February 2005. Such an
outburst was systematically monitored with the well-calibrated PCA and HEXTE
instruments on board the RXTE mission. Thanks to the good BAT temporal coverage
of the source, we have been able to cross-check BAT light-curves with
simultaneous HEXTE ones. The Crab tests have shown that our procedure recovers
both the flux and the source spectral shape over the whole FOV of the BAT
instrument. Moreover, by cross-checking GRO J1655-40 light-curves obtained by
BAT and HEXTE, we found the spectral and flux evolution of the outburst to be
in very good agreement. Using our procedure, BAT reproduces HEXTE fluxes within
a 10-15% uncertainty with a 3sigma sensitivity of ~20 mCrab for an on-axis
source, thus establishing its capability to monitor the evolution of relatively
bright hard X-rays sources.


title: On Anosov diffeomorphisms with asymptotically conformal periodic data

abstract:
  We consider transitive Anosov diffeomorphisms for which every periodic orbit
has only one positive and one negative Lyapunov exponent. We establish various
properties of such systems including strong pinching, C^{1+\beta} smoothness of
the Anosov splitting, and C^1 smoothness of measurable invariant conformal
structures and distributions. We apply these results to volume preserving
diffeomorphisms with two-dimensional stable and unstable distributions and
diagonalizable derivatives of the return maps at periodic points. We show that
a finite cover of such a diffeomorphism is smoothly conjugate to an Anosov
automorphism of a torus. As a corollary we obtain local rigidity for such
diffeomorphisms. We also establish a local rigidity result for Anosov
diffeomorphisms in dimension three.


title:
Moduli stabilization in 5D gauged supergravity with universal
  hypermultiplet and boundary superpotentials

abstract:
  We study a four-dimensional effective theory of the five-dimensional (5D)
gauged supergravity with a universal hypermultiplet and perturbative
superpotential terms at the orbifold fixed points. Among eight independent
isometries of the scalar manifold, we focus on three directions for gauging by
the graviphoton. The class of models we consider includes the 5D heterotic
M-theory and the supersymmetric Randall-Sundrum model as special limits of the
gauging parameters. We analyze the vacuum structure of such models, especially
the nature of moduli stabilization, from the viewpoint of the effective theory.
We also discuss the uplifting of supersymmetric anti-de Sitter vacua.


title:
Interferometric imaging of the sulfur-bearing molecules H2S, SO and CS
  in comet C/1995 O1 (Hale-Bopp)

abstract:
  We present observations of rotational lines of H2S, SO and CS performed in
comet C/1995 O1 (Hale-Bopp) in March 1997 with the Plateau de Bure
interferometer (IRAM). The observations provide informations on the spatial and
velocity distributions of these molecules. They can be used to constrain their
photodissociation rate and their origin. We use a radiative transfer code which
allows us to compute synthetic line profiles and interferometric maps, to be
compared to the observations. Both single-dish spectra and interferometric
spectral maps show a day/night asymmetry in the outgassing. From the analysis
of the spectral maps, including the astrometry, we show that SO and CS present
in addition a jet-like structure that may be the gaseous counterpart of the
dust high-latitude jet observed in optical images. A CS rotating jet is also
observed. Using the astrometry provided by continuum radio maps obtained in
parallel, we conclude that there is no need to invoke of nongravitational
forces acting on this comet, and provide an updated orbit. The radial extension
of H2S is found to be consistent with direct release from the nucleus. SO
displays an extended radial distribution. Assuming that SO2 is the parent of
SO, the photodissociation rate of SO is measured to be 1.5 E-4 s-1 at 1 AU from
the Sun. This is lower than most laboratory-based estimates and may suggest
that SO is not solely produced by SO2 photolysis. From the observations of
J(2-1) and J(5-4) CS lines, we deduce a CS photodissociation rate of 1 to 5 E-5
s-1. The photodissociation rate of CS2, the likely parent of CS, cannot be
constrained due to insufficient resolution, but our data are consistent with
published values. These observations illustrate the cometary science that will
be performed with the future ALMA interferometer.


title:
The Coexistence of Classical Bulges and Disky Pseudobulges in Early-Type
  Disk Galaxies

abstract:
  Close examination of so-called "pseudobulges" in several early-type disk
galaxies indicates that they are actually composite structures consisting of
both a flattened, kinematically cool disklike structure ("disky pseudobulge")
and a rounder, kinematically hot spheroidal structure ("classical bulge"). This
indicates that pseudobulges, thought to form from internal secular evolution,
and classical bulges, thought to form from rapid mergers, are not exclusive
phenomena: some galaxies can have both.


title:
The environmental dependence of the chemical properties of star-forming
  galaxies

abstract:
  We use a 0.040 < z < 0.085 sample of 37866 star-forming galaxies from the
Fourth Data Release of the Sloan Digital Sky Survey to investigate the
dependence of gas-phase chemical properties on stellar mass and environment.
The local density, determined from the projected distances to the fourth and
fifth nearest neighbours, is used as an environment indicator. Considering
environments ranging from voids, i.e., log Sigma < -0.8, to the periphery of
galaxy clusters, i.e., log Sigma =~ 0.8, we find no dependence of the
relationship between galaxy stellar mass and gas-phase oxygen abundance, along
with its associated scatter, on local galaxy density. However, the star-forming
gas in galaxies shows a marginal increase in the chemical enrichment level at a
fixed stellar mass in denser environments. Compared with galaxies of similar
stellar mass in low density environments, they are enhanced by a few per cent
for massive galaxies to about 20 per cent for galaxies with stellar masses <
10^{9.5} solar masses. These results imply that the evolution of star-forming
galaxies is driven primarily by their intrinsic properties and is largely
independent of their environment over a large range of local galaxy density.


title:
Effects of decoherence on the radiative and squeezing properties in a
  coherently driven trapped two-level atom

abstract:
  Analysis of the effects of decoherence on the radiative and squeezing
properties of a coherently driven two-level atom trapped in a resonant cavity
applying the corresponding master equation is presented. The atomic dynamics as
well as the squeezing and statistical properties of the emitted radiation are
investigated. It is found that the atom stays in the lower energy level more
often at steady state irrespective of the strength of the coherent radiation
and thermal fluctuations entering the cavity. Moreover, a strong external
coherent radiation results the splitting of the line of the emission spectrum,
whereas the decoherence broadens the width and significantly decreases the
height. It is also found that the emitted radiation exhibits photon
anti-bunching, super-Poissonian photon statistics and squeezing, despite the
presence of the decoherence which is expected to destroy the quantum features.


title:
Global Structure of Locally Convex Hypersurfaces in Finsler-Hadamard
  Manifolds

abstract:
  Locally convex compact immersed hypersurfaces in Finsler-Hadamard manifolds
with bounded T-curvature are considered. We prove that such hypersurfaces are
embedded as the boundary of convex body under certain conditions on the normal
curvatures


title: Two-proton radioactivity

abstract:
  In the first part of the present review paper, experimental results which
lead to the discovery of two-proton radioactivity are reviewed. Beyond
two-proton emission from nuclear ground states, we also discuss experimental
studies of two-proton emission from excited states populated either by nuclear
beta decay or by inelastic reactions. In the second part, we review the modern
theory of two-proton radioactivity. An outlook to future experimental studies
and theoretical developments will conclude this review.


title: Neutron star crust beyond the Wigner-Seitz approximation

abstract:
  For more than three decades, the inner crust of neutron stars, formed of a
solid lattice of nuclear clusters coexisting with a gas of electrons and
neutrons, has been traditionally studied in the Wigner-Seitz approximation. The
validity of this approximation is discussed in the general framework of the
band theory of solids, which has been recently applied to the nuclear context.
Using this novel approach, it is shown that the unbound neutrons move in the
crust as if their mass was increased.


title: Tunable Coulomb blockade in nanostructured graphene

abstract:
  We report on Coulomb blockade and Coulomb diamond measurements on an etched,
tunable single-layer graphene quantum dot. The device consisting of a graphene
island connected via two narrow graphene constrictions is fully tunable by
three lateral graphene gates. Coulomb blockade resonances are observed and from
Coulomb diamond measurements a charging energy of ~3.5 meV is extracted. For
increasing temperatures we detect a peak broadening and a transmission increase
of the nanostructured graphene barriers.


title: Irradiation-induced confinement in a quasi-one-dimensional metal

abstract:
  The anisotropic resistivity of PrBa$_2$Cu$_4$O$_8$ has been measured as a
function of electron irradiation fluence. Localization effects are observed for
extremely small amounts of disorder corresponding to electron mean-free-paths
of order 100 unit cells. Estimates of the localization corrections suggest that
this anomalous localization threshold heralds a crossover to a ground state
with pronounced one-dimensional character in which conduction electrons become
confined to a small cluster of chains.


title:
Fluctuation theorem for entropy production during effusion of a
  relativistic ideal gas

abstract:
  The probability distribution of the entropy production for the effusion of a
relativistic ideal gas is calculated explicitly. This result is then extended
to include particle and anti-particle pair production and annihilation. In both
cases, the fluctuation theorem is verified.


title: Morse theory and conjugacy classes of finite subgroups

abstract:
  We construct a CAT(0) group containing a finitely presented subgroup with
infinitely many conjugacy classes of finite-order elements. Unlike previous
examples (which were based on right-angled Artin groups) our ambient CAT(0)
group does not contain any rank 3 free abelian subgroups.
  We also construct examples of groups of type F_n inside mapping class groups,
Aut(F), and Out(F) which have infinitely many conjugacy classes of finite-order
elements.


title: Complete Reducibility and Separability

abstract:
  Let G be a reductive linear algebraic group over an algebraically closed
field of characteristic p > 0. A subgroup of G is said to be separable in G if
its global and infinitesimal centralizers have the same dimension. We study the
interaction between the notion of separability and Serre's concept of
G-complete reducibility for subgroups of G. The separability hypothesis appears
in many general theorems concerning G-complete reducibility. We demonstrate
that many of these results fail without this hypothesis. On the other hand, we
prove that if G is a connected reductive group and p is very good for G, then
any subgroup of G is separable; we deduce that under these hypotheses on G, a
subgroup H of G is G-completely reducible provided the Lie algebra of G is
semisimple as an H-module.
  Recently, Guralnick has proved that if H is a reductive subgroup of G and C
is a conjugacy class of G, then the intersection of C and H is a finite union
of H-conjugacy classes. For generic p -- when certain extra hypotheses hold,
including separability -- this follows from a well-known tangent space argument
due to Richardson, but in general, it rests on Lusztig's deep result that a
connected reductive group has only finitely many unipotent conjugacy classes.
We show that the analogue of Guralnick's result is false if one considers
conjugacy classes of n-tuples of elements from H for n > 1.


title: Simple and secure quantum key distribution with biphotons

abstract:
  The best qubit one-way quantum key distribution (QKD) protocol can tolerate
up to 14.1% in the error rate. It has been shown how this rate can be increased
by using larger quantum systems. The polarization state of a biphoton can
encode a three level quantum system - a qutrit. The realization of a QKD system
with biphotons encounters several problems in generating, manipulating and
detecting such photon states. We define those limitations and find within them
a few protocols that perform almost as well as the ideal qutrit protocol. One
advantage is that these protocols can be implemented with minor modifications
into existing single photon systems. The security of one protocol is proved for
the most general coherent attacks and the largest acceptable error rate for
this protocol is found to be around 17.7%. This is the first time, to the best
of our knowledge, that the security of qutrit QKD protocols is rigorously
analyzed against general attacks.


title: On the mathematics and physics of high genus invariants of [C^3/Z_3]

abstract:
  This paper wishes to foster communication between mathematicians and
physicists working in mirror symmetry and orbifold Gromov-Witten theory. We
provide a reader friendly review of the physics computation in
[arXiv:hep-th/0607100] that predicts Gromov-Witten invariants of [C^3/Z_3] in
arbitrary genus, and of the mathematical framework for expressing these
invariants as Hodge integrals. Using geometric properties of the Hodge classes,
we compute the unpointed invariants for g=2,3, thus providing the first high
genus mathematical check of the physics predictions.


title: Correlation functions in conformal Toda field theory I

abstract:
  Two-dimensional sl(n) quantum Toda field theory on a sphere is considered.
This theory provides an important example of conformal field theory with higher
spin symmetry. We derive the three-point correlation functions of the
exponential fields if one of the three fields has a special form. In this case
it is possible to write down and solve explicitly the differential equation for
the four-point correlation function if the fourth field is completely
degenerate. We give also expressions for the three-point correlation functions
in the cases, when they can be expressed in terms of known functions. The
semiclassical and minisuperspace approaches in the conformal Toda field theory
are studied and the results coming from these approaches are compared with the
proposed analytical expression for the three-point correlation function. We
show, that in the framework of semiclassical and minisuperspace approaches
general three-point correlation function can be reduced to the
finite-dimensional integral.


title:
Synthetic Diamond and Wurtzite Structures Self-Assemble with Isotropic
  Pair Interactions

abstract:
  Using inverse statistical-mechanical optimization techniques, we have
discovered isotropic pair interaction potentials with strongly repulsive cores
that cause the tetrahedrally coordinated diamond and wurtzite lattices to
stabilize, as evidenced by lattice sums, phonon spectra, positive-energy
defects, and self-assembly in classical molecular dynamics simulations. These
results challenge conventional thinking that such open lattices can only be
created via directional covalent interactions observed in nature. Thus, our
discovery adds to fundamental understanding of the nature of the solid state by
showing that isotropic interactions enable the self-assembly of open crystal
structures with a broader range of coordination number than previously thought.
Our work is important technologically because of its direct relevance generally
to the science of self-assembly and specifically to photonic crystal
fabrication.


title: From stars to nuclei

abstract:
  We recall the basic physical principles governing the evolution of stars with
some emphasis on the role played by the nuclear reactions. We argue that in
general it is not possible from observations of stars to deduce constraints on
the nuclear reaction rates. This is the reason why precise measurements of
nuclear reaction rates are a necessity in order to make progresses in stellar
physics, nucleosynthesis and chemical evolution of galaxies. There are however
some stars which provides useful constraint on nuclear processes. The
Wolf-Rayet stars of the WN type present at their surface CNO equilibrium
patterns. There is also the particular case of the abundance of $^{22}$Ne at
the surface of WC stars. The abundance of this element is a measure of the
initial CNO content. Very interestingly, recent determinations of its abundance
at the surface of WC stars tend to confirm that massive stars in the solar
neighborhood have initial metallicities in agreement with the Asplund et al.
(2005) solar abundances.


title: On the role of magnetic fields in abundance determinations

abstract:
  {Although there is considerable evidence supporting an ubiquitous magnetic
field in solar/stellar photospheres, its impact in the determination of
abundances has never been quantified. In this work we investigate whether the
magnetic field plays a measurable role for this kind of studies. To that end,
we carry out simulations of spectral line formation in the presence of a
magnetic field, and then use those profiles to derive the abundance of several
atomic species (Fe, Si, C and O) neglecting the magnetic field. In this way, we
find that the derived iron abundance can be significantly biased, with
systematic errors up to 0.1 dex. In the case of silicon, carbon and oxygen
their role is very marginal (errors smaller than 0.02 dex). We also find that
the effect of the magnetic field strongly depends on its inclination with
respect to the observer. We show that fields that are aligned with the observer
lead to an underestimation of the real abundance, whereas more inclined ones
overestimate it. In the case of a mixture of fields with different inclinations
these effects are likely to partly cancel each other out, making the role of
the magnetic field even less important. Finally, we derive a simple model that
can be used to determine the suitability of a spectral line when we wish to
avoid the bias introduced by the neglect of the magnetic field.


title:
Asymptotic estimates for the number of contingency tables, integer
  flows, and volumes of transportation polytopes

abstract:
  We prove an asymptotic estimate for the number of mxn non-negative integer
matrices (contingency tables) with prescribed row and column sums and, more
generally, for the number of integer feasible flows in a network. Similarly, we
estimate the volume of the polytope of mxn non-negative real matrices with
prescribed row and column sums. Our estimates are solutions of convex
optimization problems and hence can be computed efficiently. As a corollary, we
show that if row sums R=(r_1, ..., r_m) and column sums C=(c_1, ..., c_n) with
r_1 + ... + r_m =c_1 + ... +c_n =N are sufficiently far from constant vectors,
then, asymptotically, in the uniform probability space of the mxn non-negative
integer matrices with the total sum N of entries, the event consisting of the
matrices with row sums R and the event consisting of the matrices with column
sums C are positively correlated.


title: Simulation of majority rule disturbed by power-law noise

abstract:
  Simulations are reported on the Ising two-dimensional ferromagnet in the
presence of a special kind of noise. The noise spectrum P(n) follows a power
law, where P(n) is the probability of flipping randomly selected n spins at
each timestep. This is introduced to mimic the self-organized criticality as a
model influence of a complex environment. We reproduced the phase transition
similar to the case of P(n) = constant. Above some value of the noise amplitude
the magnetisation tends to zero; otherwise it remains constant after some
relaxation. Information of the initial spin orientation remains preserved to
some extent by short-range spin-spin correlations. The distribution of the
times between flips is exponential. The results are discussed as a step towards
modeling of social systems.


title:
Pascual Jordan's resolution of the conundrum of the wave-particle
  duality of light

abstract:
  In 1909, Einstein derived a formula for the mean square energy fluctuation in
black-body radiation. This formula is the sum of a wave term and a particle
term. In a key contribution to the 1925 Dreimaennerarbeit with Born and
Heisenberg, Jordan showed that one recovers both terms in a simple model of
quantized waves. So the two terms do not require separate mechanisms but arise
from a single consistent dynamical framework. Several authors have argued that
various infinities invalidate Jordan's conclusions. In this paper, we defend
Jordan's argument against such criticism. In particular, we note that the
fluctuation in a narrow frequency range, which is what Jordan calculated, is
perfectly finite. We also note, however, that Jordan's argument is incomplete.
In modern terms, Jordan calculated the quantum uncertainty in the energy of a
subsystem in an energy eigenstate of the whole system, whereas the thermal
fluctuation is the average of this quantity over an ensemble of such states.
Still, our overall conclusion is that Jordan's argument is basically sound and
that he deserves credit for resolving a major conundrum in the development of
quantum physics.


title: Type IIB Flows with N=1 Supersymmetry

abstract:
  We write general and explicit equations which solve the supersymmetry
transformations with two arbitrary complex-proportional Weyl spinors on
$\mathcal{N}=1$ supersymmetric type IIB strings backgrounds with all R-R $F_1$,
$F_3$, $F_5$ and NS-NS $H_3$ fluxes turned on using SU(3) structures. The
equations are generalizations of the ones found for specific relations between
the two spinors by Grana, Minasian, Petrini and Tomasiello in [1] and by Butti,
Grana, Minasian, Petrini and Zaffaroni in [2]. The general equations allow to
study systematically generic type IIB backgrounds with $\mathcal{N}=1$
supersymmetry. We then explore some specific classes of flows with constant
axion, flows with constant dilaton, flows on conformally Calabi-Yau
backgrounds, flows with imaginary self-dual 3-form flux, flows with constant
ratio of the two spinors, the corresponding equations are written down and some
of their features and relations are discussed.


title: Molecules in galaxies

abstract:
  The main achievements, current developments and prospects of molecular
studies in external galaxies are reviewed. They are put in the context of the
results of several decades of studies of molecules in local interstellar
medium, their chemistry and their importance for star formation. CO
observations have revealed the gross structure of molecular gas in galaxies.
Together with other molecules, they are among the best tracers of star
formation at galactic scales. Our knowledge about molecular abundances in
various local galactic environments is progressing. They trace physical
conditions and metallicity, and they are closely related to dust processes and
large aromatic molecules. Major recent developments include mega-masers, and
molecules in Active Galactic Nuclei; millimetre emission of molecules at very
high redshift; and infrared H2 emission as tracer of warm molecular gas, shocks
and photodissociation regions. The advent of sensitive giant interferometers
from the centimetre to sub-millimetre range, especially ALMA in the near future
in the mm/submm range, will open a new area for molecular studies in galaxies
and their use to trace star formation at all distances.


title: Bulge properties and dark matter content of early-type barred galaxies

abstract:
  The dynamics of a barred galaxy depends on the pattern speed of its bar. The
only direct method for measuring the pattern speed of a bar is the
Tremaine-Weinberg technique. This method is best suited to the analysis of the
distribution and dynamics of the stellar component. Therefore it has been
mostly used for early-type barred galaxies. Most of them host a classical
bulge. On the other hand, a variety of indirect methods, which are based on the
analysis of the distribution and dynamics of the gaseous component, has been
used to measure the bar pattern speed in late-type barred galaxies. Nearly all
the measured bars are as rapidly rotating as they can be. By comparing this
result with high-resolution numerical simulations of bars in dark matter halos,
it is possible to conclude that these bars reside in maximal disks.


title: Little Higgs Model Discrimination at the LHC and ILC

abstract:
  We propose a means to discriminate between the two basic variants of Little
Higgs models, the Product Group and Simple Group models, at the next generation
of colliders. It relies on a special coupling of light pseudoscalar particles
present in Little Higgs models, the pseudoaxions, to the Z and the Higgs boson,
which is present only in Simple Group models. We discuss the collider
phenomenology of the pseudoaxion in the presence of such a coupling at the LHC,
where resonant production and decay of either the Higgs or the pseudoaxion
induced by that coupling can be observed for much of parameter space. The full
allowed range of parameters, including regions where the observability is
limited at the LHC, is covered by a future ILC, where double scalar production
would be a golden channel to look for.


title:
Laser cooling in the Penning trap: an analytical model for cooling rates
  in the presence of an axializing field

abstract:
  Ions stored in Penning traps may have useful applications in the field of
quantum information processing. There are, however, difficulties associated
with the laser cooling of one of the radial motions of ions in these traps,
namely the magnetron motion. The application of a small radio-frequency
quadrupolar electric potential resonant with the sum of the two radial motional
frequencies has been shown to couple these motions and to lead to more
efficient laser cooling. We present an analytical model that enables us to
determine laser cooling rates in the presence of such an 'axializing' field. It
is found that this field leads to an averaging of the laser cooling rates for
the two motions and hence improves the overall laser cooling efficiency. The
model also predicts shifts in the motional frequencies due to the axializing
field that are in qualitative agreement with those measured in recent
experiments. It is possible to determine laser cooling rates experimentally by
studying the phase response of the cooled ions to a near resonant excitation
field. Using the model developed in this paper, we study the expected phase
response when an axializing field is present.


title: Spin-induced angular momentum switching

abstract:
  When light is transmitted through optically inhomogeneous and anisotropic
media the spatial distribution of light can be modified according to its input
polarization state. A complete analysis of this process, based on the paraxial
approximation, is presented, and we show how it can be exploited to produce a
spin-controlled-change in the orbital angular momentum of light beams
propagating in patterned space-variant-optical-axis phase plates. We also
unveil a new effect. The development of a strong modulation in the angular
momentum change upon variation of the optical path through the phase plates.


title:
Anomalous Paramagnetic Magnetization in Mixed State of CeCoIn$_5$ single
  crystals

abstract:
  Magnetization and torque measurements were performed on CeCoIn$_5$ single
crystals to study the mixed-state thermodynamics. These measurements allow the
determination of both paramagnetic and vortex responses in the mixed-state
magnetization. The paramagnetic magnetization is suppressed in the mixed state
with the spin susceptibility increasing with increasing magnetic field. The
dependence of spin susceptibility on magnetic field is due to the fact that
heavy electrons contribute both to superconductivity and paramagnetism and a
large Zeeman effect exists in this system. No anomaly in the vortex response
was found within the investigated temperature and field range.


title: A pathway to multivariate Gaussian density

abstract:
  A general principle called "conservation of the ellipsoid of concentration"
is introduced and a generalized entropic form of order 'alpha' is optimized
under this principle. It is shown that this can produce a density which can act
as a pathway to multivariate Gaussian density. The resulting entropic pathway
contains as special cases the Boltzmann-Gibbs (Shannon) and Tsallis
(Havrda-Charvat) entropic forms.


title: New Digit Results and Several Problems

abstract:
  We give some new relations for Newman digit sums respectively different
modulos and put some problems. In particular, for the odd prime modulos we put
an important conjecture.


title: Mesoscale simulations of polymer dynamics in microchannel flows

abstract:
  The non-equilibrium structural and dynamical properties of flexible polymers
confined in a square microchannel and exposed to a Poiseuille flow are
investigated by mesoscale simulations. The chain length and the flow strength
are systematically varied. Two transport regimes are identified, corresponding
to weak and strong confinement. For strong confinement, the transport
properties are independent of polymer length. The analysis of the long-time
tumbling dynamics of short polymers yields non-periodic motion with a sublinear
dependence on the flow strength. We find distinct differences for
conformational as well as dynamical properties from results obtained for simple
shear flow.


title: The 3-fold vertex via stable pairs

abstract:
  The theory of stable pairs in the derived category yields an enumerative
geometry of curves in 3-folds. We evaluate the equivariant vertex for stable
pairs on toric 3-folds in terms of weighted box counting. In the toric
Calabi-Yau case, the result simplifies to a new form of pure box counting. The
conjectural equivalence with the DT vertex predicts remarkable identities. The
equivariant vertex governs primary insertions in the theory of stable pairs for
toric varieties. We consider also the descendent vertex and conjecture the
complete rationality of the descendent theory for stable pairs.


title: Visual Binaries in the Orion Nebula Cluster

abstract:
  We have carried out a major survey for visual binaries towards the Orion
Nebula Cluster using HST images obtained with an H-alpha filter. Among 781
likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple
systems (75 binaries and 3 triples), of which 55 are new discoveries, in the
range from 0.1" to 1.5". About 9 binaries are likely line-of-sight
associations. We find a binary fraction of 8.8%+-1.1% within the limited
separation range from 67.5 to 675 AU. The field binary fraction in the same
range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T
Tauri associations have a factor 2.2 more binaries than the ONC. The binary
separation distribution function of the ONC shows unusual structure, with a
sudden steep decrease in the number of binaries as the separation increases
beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries
wider than 0.5" to binaries closer than 0.5" as a function of distance from the
Trapezium, and find that this ratio is significantly depressed in the inner
region of the ONC. The deficit of wide binaries in the central part of the
cluster is likely due to dissolution or orbital change during their passage
through the potential well of the inner cluster region. Many of the companions
are likely to be brown dwarfs.


title: Environmental Dependence of Masses and Coupling Constants

abstract:
  We construct a class of scalar field models coupled to matter that lead to
the dependence of masses and coupling constants on the ambient matter density.
Such models predict a deviation of couplings measured on the Earth from values
determined in low-density astrophysical environments, but do not necessarily
require the evolution of coupling constants with the redshift in the recent
cosmological past. Additional laboratory and astrophysical tests of \Delta
\alpha and \Delta(m_p/m_e) as functions of the ambient matter density are
warranted.


title: Research Paper on Transaction-Oriented Simulation In Ad Hoc Grids

abstract:
  This paper analyses the requirements of performing parallel
transaction-oriented simulations with a special focus on the space-parallel
approach and discrete event simulation synchronisation algorithms that are
suitable for transaction-oriented simulation and the target environment of Ad
Hoc Grids. To demonstrate the findings a Java-based parallel
transaction-oriented simulator for the simulation language GPSS/H is
implemented on the basis of the most promising Shock Resistant Time Warp
synchronisation algorithm and using the Grid framework ProActive. The
validation of this parallel simulator shows that the Shock Resistant Time Warp
algorithm can successfully reduce the number of rolled back Transaction moves
but it also reveals circumstances in which the Shock Resistant Time Warp
algorithm can be outperformed by the normal Time Warp algorithm. The conclusion
of this paper suggests possible improvements to the Shock Resistant Time Warp
algorithm to avoid such problems.


title: On Successive Refinement of Diversity for Fading ISI Channels

abstract:
  Rate and diversity impose a fundamental tradeoff in communications. This
tradeoff was investigated for Intersymbol Interference (ISI) channels in [4]. A
different point of view was explored in [1] where high-rate codes were designed
so that they have a high-diversity code embedded within them. Such diversity
embedded codes were investigated for flat fading channels and in this paper we
explore its application to ISI channels. In particular, we investigate the rate
tuples achievable for diversity embedded codes for scalar ISI channels through
particular coding strategies. The main result of this paper is that the
diversity multiplexing tradeoff for fading ISI channels is indeed successively
refinable. This implies that for fading single input single output (SISO) ISI
channels one can embed a high diversity code within a high rate code without
any performance loss (asymptotically). This is related to a deterministic
structural observation about the asymptotic behavior of frequency response of
channel with respect to fading strength of time domain taps.


title:
Nonlinear growth of firehose and mirror fluctuations in turbulent
  galaxy-cluster plasmas

abstract:
  In turbulent high-beta astrophysical plasmas (exemplified by the galaxy
cluster plasmas), pressure-anisotropy-driven firehose and mirror fluctuations
grow nonlinearly to large amplitudes, dB/B ~ 1, on a timescale comparable to
the turnover time of the turbulent motions. The principle of their nonlinear
evolution is to generate secularly growing small-scale magnetic fluctuations
that on average cancel the temporal change in the large-scale magnetic field
responsible for the pressure anisotropies. The presence of small-scale magnetic
fluctuations may dramatically affect the transport properties and, thereby, the
large-scale dynamics of the high-beta astrophysical plasmas.


title:
Thermal expansion, heat capacity and magnetostriction of RAl$_3$ (R =
  Tm, Yb, Lu) single crystals

abstract:
  We present thermal expansion and longitudinal magnetostriction data for cubic
RAl3 (R = Tm, Yb, Lu) single crystals. The thermal expansion coefficient for
YbAl3 is consistent with an intermediate valence of the Yb ion, whereas the
data for TmAl3 show crystal electric field contributions and have strong
magnetic field dependencies. de Haas-van Alphen-like oscillations were observed
in the magnetostriction data of YbAl3 and LuAl3, several new extreme orbits
were measured and their effective masses were estimated. Zero and 140 kOe
specific heat data taken on both LuAl3 and TmAl3 for T < 200 K allow for the
determination of a CEF splitting scheme for TmAl3.


title: Observations of Gamma-ray Bursts with VERITAS and Whipple

abstract:
  Many authors have predicted very-high-energy (VHE; E > 100 GeV) emission from
gamma-ray bursts (GRBs) both during the prompt phase and during the
multi-component afterglow. To date, however, there has been no definitive
detection of such emission. Recently, the Swift Satellite made the exciting
discovery that almost 50% of GRBs are accompanied by one or more X-ray flares,
which are found to occur from several seconds to many hours after the prompt
emission. The discovery of this phenomenon and the many predictions that VHE
emission should accompany these flares increases the already strong motivation
for making immediate follow-up VHE observations of GRBs. Observations of GRBs
have high priority at VERITAS, preempting any observations that may be in
progress. GRB alerts are received from the GCN via a socket connection. This is
interfaced to the VERITAS Tracking Software to minimize the time between a
notification arriving and the telescope being slewed to the GRB. We report here
on GRB observations with VERITAS and with the Whipple Telescope from 2005
through 2007.


title: Noncommutative Point Sources

abstract:
  We construct a perturbative solution to classical noncommutative gauge theory
on ${\mathbb{R}}^{3}$ minus the origin using the Groenewald-Moyal star product.
The result describes a noncommutative point charge. Applying it to the quantum
mechanics of the noncommutative hydrogen atom gives shifts in the $1S$
hyperfine splitting which are first order in the noncommutativity parameter.


title: Many-body Electronic Structure of Metallic alpha-Uranium

abstract:
  We present results for the electronic structure of alpha uranium using a
recently developed quasiparticle self-consistent GW method (QSGW). This is the
first time that the f-orbital electron-electron interactions in an actinide has
been treated by a first-principles method beyond the level of the generalized
gradient approximation (GGA) to the local density approximation (LDA). We show
that the QSGW approximation predicts an f-level shift upwards of about 0.5 eV
with respect to the other metallic s-d states and that there is a significant
f-band narrowing when compared to LDA band-structure results. Nonetheless,
because of the overall low f-electron occupation number in uranium,
ground-state properties and the occupied band structure around the Fermi energy
is not significantly affected. The correlations predominate in the unoccupied
part of the f states. This provides the first formal justification for the
success of LDA and GGA calculations in describing the ground-state properties
of this material.


title:
The Influence of Magnetic Field Geometry on the Evolution of Black Hole
  Accretion Flows: Similar Disks, Drastically Different Jets

abstract:
  Because the magneto-rotational instability is capable of exponentially
amplifying weak preexisting magnetic fields, it might be hoped that the
character of the magnetic field in accretion disks is independent of the nature
of the seed field. However, the divergence-free nature of magnetic fields in
highly conducting fluids ensures that their large-scale topology is preserved,
no matter how greatly the field intensity is changed. By performing global
two-dimensional and three-dimensional general relativistic magnetohydrodynamic
disk simulations with several different topologies for the initial magnetic
field, we explore the degree to which the character of the flows around black
holes depends on the initial topology. We find that while the qualitative
properties of the accretion flow are nearly independent of field topology,
jet-launching is very sensitive to it: a sense of vertical field consistent for
at least an inner disk inflow time is essential to the support of strong jets.


title: Back-in-time dynamics of the cluster IE 0657-56 (the Bullet System)

abstract: paper removed: double submission


title:
Correlated entanglement distillation and the structure of the set of
  undistillable states

abstract:
  We consider entanglement distillation under the assumption that the input
states are allowed to be correlated among each other. We hence replace the
usually considered independent and identically-distributed hypothesis by the
weaker assumption of merely having identical reductions. We find that whether a
state is then distillable or not is only a property of these reductions, and
not of the correlations that are present in the input state. This is shown by
establishing an appealing relation between the set of copy-correlated
undistillable states and the standard set of undistillable states: The former
turns out to be the convex hull of the latter. As an example of the usefulness
of our approach to the study of entanglement distillation, we prove a new
activation result, which generalizes earlier findings: it is shown that for
every entangled state and every positive integer k, there exists a
copy-correlated k-undistillable state such that their tensor product is
single-copy distillable. Finally, the relation of our results to the conjecture
about the existence of bound entangled states with a non-positive partial
transpose is discussed.


title: Flares from spiral waves by lensing and time-delay amplification?

abstract:
  Episodically accreting black holes are thought to produce flares when a chunk
of particles is accelerated to high velocity near the black hole horizon. This
also seems to be the case of Sagittarius A* in the Galactic Center, where the
broad-band radiation is produced, likely via the synchrotron self-Compton
mechanism. It has been proposed that strong-field gravitational lensing
magnifies the flares. The effect of lensing is generally weak and requires a
fine-tuned geometrical arrangement, which occurs with only a low probability.
However, there are several aspects that make Sagittarius A* a promising target
to reveal strong gravity effects. Unlike type II (obscured) active galaxies,
chances are that a flare is detected at high inclination, which would be
favourable for lensing. Time delays can then significantly influence the
observed flare duration and the form of light-curve profiles. Here we discuss
an idea that the impact of lensing amplification should be considerably
enhanced when the shape of the flaring clump is appropriately elongated in the
form of a spiral wave or a narrow filament, rather than a simple (circular)
spot which we employed previously within the phenomenological `orbiting spot
model'. By parameterizing the emission region in terms of the spiral shape and
contrast, we are able to extend the spot model to more complicated sources. In
the case of spirals, we notice a possibility that more photons reach a distant
observer at the same moment because of interplay between lensing and
light-travel time. The effect is not symmetrical with respect to leading versus
trailing spirals, so in principle the source geometry can be constrained. In
spite of this, the spot model seems to provide entirely adequate framework to
study the currently available data.


title:
The Atiyah--Hitchin bracket for the cubic Nonlinear Schrodinger
  equation. IV. the scattering potentials

abstract:
  This is the last in a series of four papers on Poisson formalism for the
cubic nonlinear Schrodinger equation with repulsive nonlinearity. In this paper
we consider scattering potentials.


title: Transverse stability of relativistic two-component jets

abstract:
  Context: Astrophysical jets from various sources seem to be stratified, with
a fast inner jet and a slower outer jet. As it is likely that the launching
mechanism for each component is different, their interface will develop
differential rotation, while the outer jet radius represents a second interface
where disruptions may occur. Aims: We explore the stability of stratified,
rotating, relativistic two-component jets, in turn embedded in static
interstellar medium. Methods: In a grid-adaptive relativistic hydrodynamic
simulation with the AMRVAC code, the non-linear azimuthal stability of
two-component relativistic jets is investigated. We simulate until multiple
inner jet rotations have been completed. Results: We find evidence for the
development of an extended shear flow layer between the two jet components,
resulting from the growth of a body mode in the inner jet, Kelvin-Helmholtz
surface modes at their original interface, and their nonlinear interaction.
Both wave modes are excited by acoustic waves which are reflected between the
symmetry axis and the interface of the two jet components. Their interaction
induces the growth of near stationary, counterrotating vortices at the outer
edge of the shear flow layer. The presence of a heavy external jet allows to
slow down their further development, and maintain a collimated flow. At the
outer jet boundary, small-scale Rayleigh-Taylor instabilities develop, without
disrupting the jet configuration. Conclusion: We demonstrate that the
cross-section of two-component relativistic jets, with a heavy, cold outer jet,
is non-linearly stable.


title: Estimating the final spin of a binary black hole coalescence

abstract:
  We present a straightforward approach for estimating the final black hole
spin of a binary black hole coalescence with arbitrary initial masses and
spins. Making some simple assumptions, we estimate the final angular momentum
to be the sum of the individual spins plus the orbital angular momentum of a
test particle orbiting at the last stable orbit around a Kerr black hole with a
spin parameter of the final black hole. The formula we obtain is able to
reproduce with reasonable accuracy the results from available numerical
simulations, but, more importantly, it can be used to investigate what
configurations might give rise to interesting dynamics. In particular, we
discuss scenarios which might give rise to a ``flip'' in the direction of the
total angular momentum of the system. By studying the dependence of the final
spin upon the mass ratio and initial spins we find that our simple approach
suggests that it is not possible to spin-up a black hole to extremal values
through merger scenarios irrespective of the mass ratio of the objects
involved.


title:
Entanglement Entropy in the Two-Dimensional Random Transverse Field
  Ising Model

abstract:
  The scaling behavior of the entanglement entropy in the two-dimensional
random transverse field Ising model is studied numerically through the strong
disordered renormalization group method. We find that the leading term of the
entanglement entropy always scales linearly with the block size. However,
besides this \emph{area law} contribution, we find a subleading logarithmic
correction at the quantum critical point. This correction is discussed from the
point of view of an underlying percolation transition, both at finite and at
zero temperature.


title: Inverse-Compton emission from halos around stars

abstract:
  Inverse Compton scattering by relativistic electrons produces a major
component of the diffuse emission from the Galaxy. The photon fields involved
are the cosmic microwave background and the interstellar radiation field from
stars and dust. Calculations of the inverse Compton distribution have usually
assumed a smooth ISRF, but in fact a large part of the Galactic luminosity
comes from the most luminous stars which are rare. Therefore we expect the
ISRF, and hence the inverse Compton emission, to be clumpy. We also show that
some of the most luminous stars may be visible to GLAST. In this paper we give
an update on our previous work including examples of the intensity distribution
around stars, and the predicted spectrum of Cygnus OB2.


title: A nonlinear Ramsey interferometer operating beyond the Heisenberg limit

abstract:
  We show that a dynamically evolving two-mode Bose-Einstein condensate (TBEC)
with an adiabatic, time-varying Raman coupling maps exactly onto a nonlinear
Ramsey interferometer that includes a nonlinear medium. Assuming a realistic
quantum state for the TBEC, namely the SU(2) coherent spin state, we find that
the measurement uncertainty of the ``path-difference'' phase shift scales as
the standard quantum limit (1/N^{1/2}) where N is the number of atoms, while
that for the interatomic scattering strength scales as 1/N^{7/5}, overcoming
the Heisenberg limit of 1/N.


title:
Dense Molecular Gas In A Young Cluster Around MWC 1080 -- Rule Of The
  Massive Star

abstract:
  We present CS $J = 2 \to 1$, $^{13}$CO $J = 1 \to 0$, and C$^{18}$O $J = 1
\to 0$, observations with the 10-element Berkeley Illinois Maryland Association
(BIMA) Array toward the young cluster around the Be star MWC 1080. These
observations reveal a biconical outflow cavity with size $\sim$ 0.3 and 0.05 pc
for the semimajor and semiminor axis and $\sim$ 45$\arcdeg$ position angle.
These transitions trace the dense gas, which is likely the swept-up gas of the
outflow cavity, rather than the remaining natal gas or the outflow gas. The gas
is clumpy; thirty-two clumps are identified. The identified clumps are
approximately gravitationally bound and consistent with a standard isothermal
sphere density, which suggests that they are likely collapsing protostellar
cores. The gas kinematics suggests that there exists velocity gradients
implying effects from the inclination of the cavity and MWC 1080. The
kinematics of dense gas has also been affected by either outflows or stellar
winds from MWC 1080, and lower-mass clumps are possibly under stronger effects
from MWC 1080 than higher-mass clumps. In addition, low-mass cluster members
tend to be formed in the denser and more turbulent cores, compared to isolated
low-mass star-forming cores. This results from contributions of nearby forming
massive stars, such as outflows or stellar winds. Therefore, we conclude that
in clusters like the MWC 1080 system, effects from massive stars dominate the
star-forming environment in both the kinematics and dynamics of the natal cloud
and the formation of low-mass cluster members. This study provides insights
into the effects of MWC 1080 on its natal cloud, and suggests a different
low-mass star forming environment in clusters compared to isolated star
formation.


title: An embedding theorem for automorphism groups of Cartan geometries

abstract:
  We prove a theorem relating the automorphism group of a Cartan geometry to
the group on which the geometry is modeled: a component of the adjoint
representation of the first embeds in the adjoint representation of the second.
Consequences of the theorem include general bounds on the rank and nilpotence
degree of an automorphism group; a result asserting local homogeneity and
completeness of parabolic geometries admitting a maximal-rank group of
automorphisms; and a local freeness theorem for actions additionally preserving
a continuous volume form.


title: Multi-boson correlations using wave-packets II

abstract:
  We investigate the analytically solvable pion-laser model, and its
generalization to arbitrary multiplicity distributions. Although this kind of
extension of the model is possible, the pion laser model in its original form
is unique: it is the only model in its class that has an analytic solution.


title: Effect of external stress on the thermal melting of DNA

abstract:
  We discuss the effects of external stress on the thermal denaturation of
homogeneous DNA. Pulling double-stranded DNA at each end exerts a profound
effect on the thermal denaturation, or melting, of a long segment of this
molecule. We discuss the effects on this transition of a stretching force
applied to opposite ends of one of the DNA strands, including full
consideration of the consequences of excluded volume, the analysis of which is
greatly simplified in this case. We also discuss the interplay of thermal
denaturation and force-generated separation when the tension is generated by a
force at the end of the duplexed strands and an equal and opposite force is
applied to the other end of the second strand.


title: External Control of a Metal-Insulator Transition in GaMnAs Wires

abstract:
  Quantum transport in disordered ferromagnetic (III,Mn)V semiconductors is
studied theoretically. Mesoscopic wires exhibit an Anderson disorder-induced
metal-insulator transition that can be controlled by a weak external magnetic
field. This metal-insulator transition should also occur in other materials
with large anisotropic magneto resistance effects. The transition can be useful
for studies of zero-temperature quantum critical phase transitions and
fundamental material properties.


title: KdV6: An Integrable System

abstract:
  $K^2 S^2 T [5]$ recently derived a new 6$^{th}$-order wave equation $KdV6$:
  $(\partial^2_x + 8u_x \partial_x + 4u_{xx})(u_t + u_{xxx} + 6u_x^2) = 0$,
found a linear problem and an auto-B${\ddot{\rm{a}}}$ckclund transformation for
it, and conjectured its integrability in the usual sense. We prove this
conjecture by constructing an infinite commuting hierarchy $KdV_n6$ with a
common infinite set of conserved densities. A general construction is presented
applicable to any bi-Hamiltonian system (such as all standard Lax equations,
continuous and discrete) providing a nonholonomic perturbation of it. This
perturbation is conjectured to preserve integrability. That conjecture is
verified in a few representative cases: the classical long-wave equations, the
Toda lattice (both continuous and discrete), and the Euler top.


title:
Eliashberg theory of superconductivity and inelastic rare-earth impurity
  scattering in filled skutterudite La$_{1-x}$Pr$_{x}$Os$_{4}$Sb$_{12}$

abstract:
  We study the influence of inelastic rare-earth impurity scattering on
electron-phonon mediated superconductivity and mass renormalization in
(La$_{1-x}$Pr$_{x}$)Os$_{4}$Sb$_{12}$ compounds. Solving the strong coupling
Eliashberg equations we find that the dominant quadrupolar component of the
inelastic scattering on Pr impurities yields an enhancement of the
superconducting transition temperature T$_c$ in LaOs$_{4}$Sb$_{12}$ and
increases monotonically as a function of Pr concentration. The calculated
results are in good agreement with the experimentally observed T$_c (x)$
dependence. Our analysis suggests that phonons and quadrupolar excitations
cause the attractive electron interaction which results in the formation of
Cooper pairs and singlet superconductivity in PrOs$_{4}$Sb$_{12}$.


title:
Effect of Salt Concentration on the Electrophoretic Speed of a
  Polyelectrolyte through a Nanopore

abstract:
  In a previous paper [S. Ghosal, Phys. Rev. E 74, 041901 (2006)] a
hydrodynamic model for determining the electrophoretic speed of a
polyelectrolyte through an axially symmetric slowly varying nanopore was
presented in the limit of a vanishingly small Debye length. Here the case of a
finite Debye layer thickness is considered while restricting the pore geometry
to that of a cylinder of length much larger than the diameter. Further, the
possibility of a uniform surface charge on the walls of the nanopore is taken
into account. It is thereby shown that the calculated transit times are
consistent with recent measurements in silicon nanopores.


title: Asymptotic Safety

abstract:
  Asymptotic safety is a set of conditions, based on the existence of a
nontrivial fixed point for the renormalization group flow, which would make a
quantum field theory consistent up to arbitrarily high energies. After
introducing the basic ideas of this approach, I review the present evidence in
favor of an asymptotically safe quantum field theory of gravity.


title: Coherent Communication with Linear Optics

abstract:
  We show how to implement several continuous-variable coherent protocols with
linear optics. Noise can accumulate when implementing each coherent protocol
with realistic optical devices. Our analysis bounds the level of noise
accumulation. We highlight the connection between a coherent channel and a
nonlocal quantum nondemolition interaction and give two new protocols that
implement a coherent channel. One protocol is superior to a previous method for
a nonlocal quantum nondemolition interaction because it requires fewer
communication resources. We then show how continuous-variable coherent
superdense coding implements two nonlocal quantum nondemolition interactions
with a quantum channel and bipartite entanglement. We finally show how to
implement continuous-variable coherent teleportation experimentally and provide
a way to verify the correctness of its operation.


title: Thermodynamics of Quasi-Particles

abstract:
  We present in this work a generalization of the solution of Gorenstein and
Yang for a consistent thermodynamics for systems with a temperature dependent
Hamiltonian. We show that there is a large class of solutions, work out three
particular ones, and discuss their physical relevance. We apply the particular
solutions for an ideal gas of quasi-gluons, and compare the calculation to
lattice and perturbative QCD results.


title:
Arecibo HI Absorption Measurements of Pulsars and the Electron Density
  at Intermediate Longitudes in the First Galactic Quadrant

abstract:
  We have used the Arecibo telescope to measure the HI absorption spectra of
eight pulsars. We show how kinematic distance measurements depend upon the
values of the galactic constants R_o and Theta_o, and we select our preferred
current values from the literature. We then derive kinematic distances for the
low-latitude pulsars in our sample and electron densities along their lines of
sight. We combine these measurements with all others in the inner galactic
plane visible from Arecibo to study the electron density in this region. The
electron density in the interarm range 48 degrees < l < 70 degrees is [0.017
(-0.007,+0.012) (68% c.l.)] cm^(-3). This is 0.75 (-0.22,+0.49) (68% c.l.) of
the value calculated by the Cordes & Lazio (2002) galactic electron density
model. The model agrees more closely with electron density measurements toward
Arecibo pulsars lying closer to the galactic center, at 30 degrees<l<48
degrees. Our analysis leads to the best current estimate of the distance of the
relativistic binary pulsar B1913+16: d=(9.0 +/- 3) kpc.
  We use the high-latitude pulsars to search for small-scale structure in the
interstellar hydrogen observed in absorption over multiple epochs. PSR B0301+19
exhibited significant changes in its absorption spectrum over 22 yr, indicating
HI structure on a ~500 AU scale.


title: Non-birational twisted derived equivalences in abelian GLSMs

abstract:
  In this paper we discuss some examples of abelian gauged linear sigma models
realizing twisted derived equivalences between non-birational spaces, and
realizing geometries in novel fashions. Examples of gauged linear sigma models
with non-birational Kahler phases are a relatively new phenomenon. Most of our
examples involve gauged linear sigma models for complete intersections of
quadric hypersurfaces, though we also discuss some more general cases and their
interpretation. We also propose a more general understanding of the
relationship between Kahler phases of gauged linear sigma models, namely that
they are related by (and realize) Kuznetsov's `homological projective duality.'
Along the way, we shall see how `noncommutative spaces' (in Kontsevich's sense)
are realized physically in gauged linear sigma models, providing examples of
new types of conformal field theories. Throughout, the physical realization of
stacks plays a key role in interpreting physical structures appearing in GLSMs,
and we find that stacks are implicitly much more common in GLSMs than
previously realized.


title: On the Lifetime of Quasi-Stationary States in Non-Relativistic QED

abstract:
  We consider resonances in the Pauli-Fierz model of non-relativistic QED. We
use and slightly modify the analysis developed by Bach, Froehlich, and Sigal to
obtain an upper and lower bound on the lifetime of quasi-stationary states.


title:
Confining solutions of $(n+1)$-dimensional Yang-Mills equations for flat
  and curved space-time with $n \le 3$

abstract:
  We obtain exact static solutions of the $(n+1)$-dimensional SU(3) Yang-Mills
equations for both flat and curved space-time cases with $n \le 3$. We find
that the solutions obtained are confining functions for $n = 1, 2, 3$. We apply
the $(3+1)$ curved space-time solution to the anti-de Sitter and Schwarzschild
metrics.


title: Noise limits in the assembly of diffraction data

abstract:
  We obtain an information theoretic criterion for the feasibility of
assembling diffraction signals from noisy tomographs when the positions of the
tomographs within the signal are unknown. For shot-noise limited data, the
minimum number of detected photons per tomograph for successful assembly is
much smaller than previously believed necessary, growing only logarithmically
with the number of resolution elements of the diffracting object. We also
demonstrate assembly up to the information theoretic limit with a
constraint-based algorithm.


title: Remarks on the waterbag model of dispersionless Toda Hierarchy

abstract:
  We construct the free energy associated with the waterbag model of dToda.
Also, the relations of conserved densities are investigated


title:
Estimating copula measure using ranks and subsampling: a simulation
  study

abstract:
  We describe here a new method to estimate copula measure. From N observations
of two variables X and Y, we draw a huge number m of subsamples (size n<N), and
we compute the joint ranks in these subsamples. Then, for each bivariate rank
(p,q) (0<p,q<n+1), we count the number of subsamples such that there exist an
observation of the subsample with bivariate rank (p,q). This counting gives an
estimate of the density of the copula. The simulation study shows that this
method seems to gives a better than the usual kernel method. The main advantage
of this new method is then we do not need to choose and justify the kernel. In
exchange, we have to choose a subsample size: this is in fact a problem very
similar to the bandwidth choice. We have then reduced the overall difficulty.


title:
Amplification of High Harmonics Using Weak Perturbative High Frequency
  Radiation

abstract:
  The mechanism underlying the substantial amplification of the high-order
harmonics q \pm 2K (K integer) upon the addition of a weak seed XUV field of
harmonic frequency q\omega to a strong IR field of frequency \omega is analyzed
in the framework of the quantum-mechanical Floquet formalism and the
semiclassical re-collision model. According to the Floquet analysis, the
high-frequency field induces transitions between several Floquet states and
leads to the appearance of new dipole cross terms. The semiclassical
re-collision model suggests that the origin of the enhancement lies in the
time-dependent modulation of the ground electronic state induced by the XUV
field.


title: Current-Induced Torques in Magnetic Metals: Beyond Spin Transfer

abstract:
  Current-induced torques on ferromagnetic nanoparticles and on domain walls in
ferromagnetic nanowires are normally understood in terms of transfer of
conserved spin angular momentum between spin-polarized currents and the
magnetic condensate. In a series of recent articles we have discussed a
microscopic picture of current-induced torques in which they are viewed as
following from exchange fields produced by the misaligned spins of current
carrying quasiparticles. This picture has the advantage that it can be applied
to systems in which spin is not approximately conserved. More importantly, this
point of view makes it clear that current-induced torques can also act on the
order parameter of an antiferromagnetic metal, even though this quantity is not
related to total spin. In this informal and intentionally provocative review we
explain this picture and discuss its application to antiferromagnets.


title: Exact and Perturbed Friedmann-Lemaitre Cosmologies

abstract:
  In this thesis we first apply the 1+3 covariant description of general
relativity to analyze n-fluid Friedmann-Lemaitre (FL) cosmologies; that is,
homogeneous and isotropic cosmologies whose matter-energy content consists of n
non-interacting fluids. We are motivated to study FL models of this type as
observations suggest the physical universe is closely described by a FL model
with a matter content consisting of radiation, dust and a cosmological
constant. Secondly, we use the 1+3 covariant description to analyse scalar,
vector and tensor perturbations of FL cosmologies containing a perfect fluid
and a cosmological constant. In particular, we provide a thorough discussion of
the behaviour of perturbations in the physically interesting cases of a dust or
radiation background.


title: A lower bound on the subriemannian distance for H\"older distributions

abstract:
  Whereas subriemannian geometry usually deals with smooth horizontal
distributions, partially hyperbolic dynamical systems provide many examples of
subriemannian geometries defined by non-smooth (namely, H\"older continuous)
distributions. These distributions are of great significance for the behavior
of the parent dynamical system. The study of H\"older subriemannian geometries
could therefore offer new insights into both dynamics and subriemannian
geometry. In this paper we make a small step in that direction: we prove a
H\"older-type lower bound on the subriemannian distance for H\"older continuous
nowhere integrable codimension one distributions. This bound generalizes the
well-known square root bound valid in the smooth case.


title: Symmetry-Induced Tunnelling in One-Dimensional Disordered Potentials

abstract:
  A new mechanism of tunnelling at macroscopic distances is proposed for a wave
packet localized in one-dimensional disordered potential with mirror symmetry,
V(-x)=V(x). Unlike quantum tunnelling through a regular potential barrier,
which occurs only at the energies lower then the barrier height, the proposed
mechanism of tunnelling exists even for weak white-noise-like scattering
potentials. It also exists in classical circuits of resonant contours with
random resonant frequencies. The latter property may be used as a new method of
secure communication, which does not require coding and decoding of the
transmitting signal.


title: Search for a Solution of the Pioneer Anomaly

abstract:
  In 1972 and 1973 the Pioneer 10 and 11 missions were launched. They were the
first to explore the outer solar system and achieved stunning breakthroughs in
deep-space exploration. But beginning in about 1980 an unmodeled force of \sim
8 \times 10^{-8} cm/s^2, directed approximately towards the Sun, appeared in
the tracking data. It later was unambiguously verified as being in the data and
not an artifact. The cause remains unknown (although radiant heat remains a
likely origin). With time more and more effort has gone into understanding this
anomaly (and also possibly related effects). We review the situation and
describe ongoing programs to resolve the issue.


title: Rapid-purification protocols for optical homodyning

abstract:
  We present a number of rapid-purification feedback protocols for optical
homodyne detection of a single optical qubit. We derive first a protocol that
speeds up the rate of increase of the average purity of the system, and find
that like the equivalent protocol for a non-disspative measurement, this
generates a deterministic evolution for the purity in the limit of strong
feedback. We also consider two analogues of the Wiseman-Ralph
rapid-purification protocol in this setting, and show that like that protocol
they speed up the average time taken to reach a fixed level of purity. We also
examine how the performance of these algorithms changes with detection
efficiency, being an important practical consideration.


title: Observations of the Crab Nebula and Pulsar with VERITAS

abstract:
  Observations of the Crab Nebula have proven to be the best tool to calibrate
and to characterize the performance of a Cherenkov telescope. Scientifically,
it is interesting to measure the energy spectrum of the Crab Nebula close to
the inverse-Compton peak where a deviation is expected from the power law seen
at energies above 300 GeV. Additionally, it is important to search for pulsed
emission from the Crab Pulsar at energies beyond the 10 GeV upper limit of the
EGRET pulsar detection. Since current models predict a cut-off in pulsed
emission between 10 and 100 GeV, measurements at energies close to this range
may help to discriminate between them. We observed the Crab extensively in the
2006-2007 season during the VERITAS 2- and 3-telescope commissioning phases.
Using this data set we reconstructed a preliminary energy spectrum of the
signal from the Crab Nebula. We also measured the optical pulsed signal to
validate our GPS time-stamping and barycentering techniques and obtained an
upper limit for the pulsed emission at gamma-ray energies.


title:
Results from the Blazar Monitoring Campaign at the Whipple 10m Gamma-ray
  Telescope

abstract:
  In September 2005, the observing program of the Whipple 10 m gamma-ray
telescope was redefined to be dedicated almost exclusively to AGN monitoring.
Since then the five Northern Hemisphere blazars that had already been detected
at Whipple are monitored routinely each night that they are visible. Thanks to
the efforts of a large number of multiwavelength collaborators, the first year
of this program has been very successful. We report here on the analysis of
Markarian 421 observations taken from November, 2005 to May, 2006 in the
gamma-ray, X-ray, optical and radio bands.


title:
Two-mode variational Monte Carlo study of Quasiparticle excitations in
  cuprates

abstract:
  Recent measurements of quasiparticles in hole-doped cuprates reveal highly
unusual features: 1) the doping-independent Fermi velocity, 2) two energy
scales in the quasiparticle spectral function, and 3) a suppression of the low
energy spectral weight near the zone center. The underlying mechanism is under
hot debate. We addressed these important issues by a novel two-mode variational
Monte Carlo (VMC) study of the t-J model. We obtained results in agreement with
the experiments but without invoking extrinsic effects. Besides, we resolved a
long standing issue of the sum rule for quasiparticle spectral weights in VMC
studies. The electron doped case was also discussed.


title:
Signatures of the Baryon Acoustic Oscillations on 21cm Emission
  Background

abstract:
  The baryon acoustic oscillations (BAO) prior to recombination should be
imprinted onto the 21cm emission background from the epoch of reionization
through the underlying density perturbations. Using an analytical approach for
both matter power spectrum (CDM+baryons) and reionization process, we
demonstrate the BAO induced signatures on the power spectrum of 21cm emission
fluctuations. Future low-frequency radio telescopes such as LOFAR and MWA
should be able to detect these weak BAO wiggles with an integration time of
$\sim1$ year. A combination of the BAO measurements at different redshifts
$z\approx1000$ (CMB), $z\approx10$ (epoch of reionization) and $z\approx0$
(clustering of galaxies) may allow one to set more robust constraints on the
determinations of cosmological parameters including dark energy and its
equation of state.


title:
The Sydney University Stellar Interferometer: A Major Upgrade to
  Spectral Coverage and Performance

abstract:
  A new beam-combination and detection system has been installed in the Sydney
University Stellar Interferometer working at the red end of the visual spectrum
(wavelength range 500-950 nm) to complement the existing blue-sensitive system
(wavelength range 430-520 nm) and to provide an increase in sensitivity.
Dichroic beam-splitters have been introduced to allow simultaneous observations
with both spectral system, albeit with some restriction on the spectral range
of the longer wavelength system (wavelength range 550-760 nm). The blue system
has been upgraded to allow remote selection of wavelength and spectral
bandpass, and to enable simultaneous operation with the red system with the
latter providing fringe-envelope tracking. The new system and upgrades are
described and examples of commissioning tests presented. As an illustration of
the improvement in performance the measurement of the angular diameter of the
southern F supergiant delta CMa is described and compared with previous
determinations.


title: The Emergent Flux and Effective Temperature of Delta Canis Majoris

abstract:
  New angular diameter determinations for the bright southern F8 supergiant
Delta CMa enable the bolometric emergent flux and effective temperature of the
star to be determined with improved accuracy. The spectral flux distribution
and bolometric flux have been determined from published photometry and
spectrophotometry and combined with the angular diameter to derive the
bolometric emergent flux F = (6.50 plus/minus 0.24) x 10^7 W/m^2 and the
effective temperature Teff = 5818 plus/minus 53 K. The new value for the
effective temperature is compared with previous interferometric and infrared
flux method determinations. The accuracy of the effective temperature is now
limited by the uncertainty in the bolometric flux rather than by the
uncertainty in the angular diameter.


title: Open-closed moduli spaces and related algebraic structures

abstract:
  We set up a Batalin-Vilkovisky Quantum Master Equation for open-closed string
theory and show that the corresponding moduli spaces give rise to a solution, a
generating function for their fundamental chains. The equation encodes the
topological structure of the compactification of the moduli space of bordered
Riemann surfaces. The moduli spaces of bordered J-holomorphic curves are
expected to satisfy the same equation, and from this viewpoint, our paper
treats the case of the target space equal to a point. We also introduce the
notion of a symmetric Open-Closed Topological Conformal Field Theory and study
the L_\infty and A_\infty algebraic structures associated to it.


title: Error correction optimisation in the presence of X/Z asymmetry

abstract:
  By taking into account the physical nature of quantum errors it is possible
to improve the efficiency of quantum error correction. Here we consider an
optimisation to conventional quantum error correction which involves exploiting
asymmetries in the rates of X and Z errors by reducing the rate of X
correction. As an example, we apply this optimisation to the [[7,1,3]] code and
make a comparison with conventional quantum error correction. After two levels
of concatenated error correction we demonstrate a circuit depth reduction of at
least 43% and reduction in failure rate of at least 67%. This improvement
requires no additional resources and the required error asymmetry is likely to
be present in most physical quantum computer architectures.


title:
Features of the Acoustic Mechanism of Core-Collapse Supernova Explosions
  : Revisited using the Kinetic Approach

abstract:
  The discrete kinetic model is used to study the propagation of sound waves in
system of hard-disk-like rotating stars (or vortex gases). The anomalous
(negative) attenuation or amplification which is possibly due to the binary
collision of a dilute-enough rotating disk (or vortex-gas) system (each with
opposite-sign rotating direction or angular momenta but the total (net) angular
momenta or vorticity is zero) or microreversibility might arise from the
implicit balance of the angular momentum during encounter and give clues to the
understanding of possible acceleration of cosmic rays passing through this kind
of channel and direct or inverse vortex-gas cascades in two-dimensional
turbulence of astrophysical problems.


title:
The Cosmic MeV Gamma-ray Background and Hard X-ray Spectra of Active
  Galactic Nuclei: Implications for the Origin of Hot AGN Coronae

abstract:
  The origin of the extragalactic gamma-ray background radiation at 1-10 MeV is
still unknown. Although the cosmic X-ray background (CXB) up to a few hundreds
keV can be accounted for by the sum of Active Galactic Nuclei (AGNs), current
models of AGN spectra cannot explain the background spectrum beyond ~1 MeV,
because of the thermal exponential cutoff of electron energy distribution
assumed in the models. Here we construct a new spectral model by calculating
the Comptonization process including nonthermal electrons, which are expected
to exist in an AGN hot corona if it is heated by magnetic reconnections. We
show that the MeV background spectrum can nicely be explained by our model,
when coronal electrons have a nonthermal power-law component whose total energy
is a few percent of the thermal component and whose spectral index is d(ln
N_e)/d(ln E_e) ~ -4. Although the MeV gamma-ray flux from such a component in
nearby AGN spectra is below the detection limit of past observations, it could
be detected by planned future MeV detectors. We point out that the amount of
the nonthermal component and its electron index are similar to those found for
electrons accelerated by magnetic reconnections in solar flares and the Earth
magnetosphere, giving a support to the reconnection hypothesis for the origin
of hot AGN coronae.


title:
The Keck Aperture Masking Experiment: Multi-Wavelength Observations of 6
  Mira Variables

abstract:
  The angular diameters of six oxygen rich Mira-type long-period variables have
been measured at various near-infrared (NIR) wavelengths using the aperture
masking technique in an extensive observing program from 1997 Jan to 2004 Sep.
These data sets span many pulsation cycles of the observed objects and
represent the largest study of multi-wavelength, multi-epoch interferometric
angular diameter measurements on Mira stars to date. The calibrated visibility
data of o Cet, R Leo, R Cas, W Hya, chi Cyg and R Hya are fitted using a
uniform disk brightness distribution model to facilitate comparison between
epochs, wavelengths and with existing data and theoretical models. The
variation of angular diameter as a function of wavelength and time are studied,
and cyclic diameter variations are detected for all objects in our sample.
These variations are believed to stem from time-dependent changes of density
and temperature (and hence varying molecular opacities) in different layers of
these stars. The similarities and differences in behaviour between these
objects are analyzed and discussed in the context of existing theoretical
models. Furthermore, we present time-dependent 3.08 micron angular diameter
measurements, probing for the first time these zones of probable dust
formation, which show unforeseen sizes and are consistently out of phase with
other NIR layers shown in this study. The S-type Mira chi Cyg exhibits
significantly different behaviour compared to the M-type Miras in this study.


title: S-integral preperiodic points for dynamical systems over number fields

abstract:
  Given a rational map $\phi: {\mathbb P}^1\to {\mathbb P}^1$ defined over a
number field $K$, we prove a finiteness result for $\phi$-preperiodic points
which are $S$-integral with respect to a non-preperiodic point $P$, provided
$P$ satisfies a certain local condition at each place. This verifies a special
case of a conjecture of S. Ih.


title:
A New Perspective on Multi-user Power Control Games in Interference
  Channels

abstract:
  This paper considers the problem of how to allocate power among competing
users sharing a frequency-selective interference channel. We model the
interaction between selfish users as a non-cooperative game. As opposed to the
existing iterative water-filling algorithm that studies the myopic users, this
paper studies how a foresighted user, who knows the channel state information
and response strategies of its competing users, should optimize its
transmission strategy. To characterize this multi-user interaction, the
Stackelberg equilibrium is introduced, and the existence of this equilibrium
for the investigated non-cooperative game is shown. We analyze this interaction
in more detail using a simple two-user example, where the foresighted user
determines its transmission strategy by solving as a bi-level program which
allows him to account for the myopic user's response. It is analytically shown
that a foresighted user can improve its performance, if it has the necessary
information about its competitors. Since the optimal solution of Stackelberg
equilibrium is computationally prohibitive, we propose a practical
low-complexity approach based on Lagrangian duality theory. Numerical
simulations verify the performance improvements. Possible ways to acquire the
required information and to extend the formulation to more than two users are
also discussed.


title: Logarithmic vector fields and hyperbolicity

abstract:
  In this article we prove that the complement of a very generic curve of
degree at least equal to 14 in the complex projective plane is hyperbolic in
the sense of Kobayashi. Thus, using a new method, we improve the former known
bound obtained by El Goul. We also improve the case of a very generic curve
with two components.


title: Hyperbolicit\'e des vari\'et\'es complexes

abstract:
  These notes were written for the Cours Peccot given at the Coll\`ege de
France in 2007.


title: Non-linear rheology of layered systems - a phase model approach

abstract:
  We study non-linear rheology of a simple theoretical model developed to mimic
layered systems such as lamellar structures under shear. In the present work we
study a 2-dimensional version of the model which exhibits a Kosterlitz-Thouless
transition in equilibrium at a critical temperature Tc. While the system
behaves as Newtonain fluid at high temperatures T > Tc, it exhibits shear
thinning at low temperatures T < Tc. The non-linear rheology in the present
model is understood as due to motions of edge dislocations and resembles the
non-linear transport phenomena in superconductors by vortex motions.