title: High resolution optical spectroscopy of Plaskett's star

abstract:
  We present here the analysis of an extensive set of high resolution optical
spectra of Plaskett's star (HD 47129). We use a disentangling method to
separate the individual spectra of each star. We derive a new orbital solution
and discuss the spectral classification of both components. A Doppler
tomography technique applied to the emission lines H alpha and He II 4686
yields a Doppler map that illustrates the wind interactions in the system.
Finally, an atmosphere code is used to determine the different chemical
abundances of the system components and the wind parameters. HD 47129 appears
to be an O8 III/I + O7.5 III binary system in a post RLOF evolutionary stage,
where matter has been transferred from the primary to the secondary star. The
He overabundance of the secondary supports this scenario. In addition, the N
overabundance and C underabundance of the primary component confirm previous
results based on X-ray spectroscopy and indicate that the primary is an evolved
massive star. Furthermore, the secondary star has a large rotational velocity
that deforms its surface, leading to a non-uniform distribution in effective
temperature. This could explain the variations in the equivalent widths of the
secondary lines with phase. We suggest that the wind of the secondary star is
confined near the equatorial plane because of its high rotational velocity,
affecting the ram pressure equilibrium in the wind interaction zone.


title: The Air-Fluorescence Yield

abstract:
  Detection of the air-fluorescence radiation induced by the charged particles
of extensive air showers is a well-established technique for the study of
ultra-high energy cosmic rays. Fluorescence telescopes provide a nearly
calorimetric measure of the primary energy. Presently the main source of
systematic uncertainties comes from our limited accuracy in the fluorescence
yield, that is, the number of fluorescence photons emitted per unit of energy
deposited in the atmosphere by the shower particles. In this paper the current
status of our knowledge on the fluorescence yield both experimental an
theoretical will be discussed.


title:
The temperature dependence of lipid membrane permeability, its quantized
  nature, and the influence of anesthetics

abstract:
  We investigate the permeability of lipid membranes for fluorescence dyes and
ions. We find that permeability reaches a maximum close to the chain melting
transition of the membranes. Close to transitions, fluctuations in area and
compressibility are high, leading to an increased likelihood of spontaneous
lipid pore formation. Fluorescence Correlation Spectroscopy (FCS) reveals the
permeability for rhodamine dyes across 100 nm vesicles. Using FCS, we find that
the permeability of vesicle membranes for fluorescence dyes is within error
proportional to the excess heat capacity. To estimate defect size we measure
the conductance of solvent-free planar lipid bilayer. Microscopically, we show
that permeation events appear as quantized current events. Further, we
demonstrate that anesthetics lead to a change in membrane permeability that can
be predicted from their effect on heat capacity profiles. Depending on
temperature, the permeability can be enhanced or reduced. We demonstrate that
anesthetics decrease channel conductance and ultimately lead to 'blocking' of
the lipid pores in experiments performed at or above the chain melting
transition. Our data suggest that the macroscopic increase in permeability
close to transitions and microscopic lipid channel formation are the same
physical process.


title:
A random fiber bundle with many discontinuities in the threshold
  distribution

abstract:
  We study the breakdown of a random fiber bundle model (RFBM) with
$n$-discontinuities in the threshold distribution using the global load sharing
scheme. In other words, $n+1$ different classes of fibers identified on the
basis of their threshold strengths are mixed such that the strengths of the
fibers in the $i-th$ class are uniformly distributed between the values
$\sigma_{2i-2}$ and $\sigma_{2i-1}$ where $1 \leq i \leq n+1$. Moreover, there
is a gap in the threshold distribution between $i-th$ and $i+1-th$ class. We
show that although the critical stress depends on the parameter values of the
system, the critical exponents are identical to that obtained in the recursive
dynamics of a RFBM with a uniform distribution and global load sharing. The
avalanche size distribution (ASD), on the other hand, shows a non-universal,
non-power law behavior for smaller values of avalanche sizes which becomes
prominent only when a critical distribution is approached. We establish that
the behavior of the avalanche size distribution for an arbitrary $n$ is
qualitatively similar to a RFBM with a single discontinuity in the threshold
distribution ($n=1$), especially when the density and the range of threshold
values of fibers belonging to strongest ($n+1$)-th class is kept identical in
all the cases.


title:
Effect of the curvature on a statistical model of Quark-Gluon-Plasma
  fireball in the hadronic medium

abstract:
  The free energy of a Quark-Gluon Plasma fireball in the hadronic medium is
calculated in the Ramanathan et al. statistical model including the effect of
curvature. The result with this curvature is found to produce significant
improvement from earlier results in all the parameters we calculated. The
surface tension with this curvature effect is found to be $ 0.17 T_{c}^{3}$,
which is two times the earlier value of surface tension which is $ 0.078
T_{c}^{3} $, and it is nearly close to the lattice value $0.24 T_{c}^{3} $. The
speed of sound calculated with curvature correction is still found to be
smaller in comparision with the standard speed of sound in the QGP droplet.


title:
Searching for the secondary eclipse of CoRoT-Exo-2b and its transit
  timing variations

abstract:
  With more than 80 transits observed in the CoRoT light curve with a cadence
of 32 s, CoRoT-Exo-2b provides an excellent case to search for the secondary
eclipse of the planet, with an expected signal of less than 10^-4 in relative
flux. The activity of the star causes a modulation on the flux that makes the
detection of this signal challenging. We describe the technique used to seek
for the secondary eclipse, that leads to a tentative 2.5 sigma detection of a
5.5x10^-5 eclipse. If the effect of the spots are not taken into account, the
times of transit centers will also be affected. They could lead to an erroneous
detection of periodic transit timing variations of ~20 s and with a 7.45 d
period. By measuring the transit central times at different depths of the
transit (transit bisectors), we show that there are no such periodic variations
in the CoRoT-Exo-2b O-C residuals larger than ~10 s.


title: When are dual Cayley automaton semigroups finite?

abstract:
  In this note we prove that, for a finite semigroup $S$, the dual
  Cayley automaton semigroup $\mathbf{C^{\ast}}(S)$ is finite if and only if
$S$ is $\mathcal{H}$-trivial and has no non-trivial right zero subsemigroups.


title: Characterizing entanglement with geometric entanglement witnesses

abstract:
  We show how to detect entangled, bound entangled, and separable bipartite
quantum states of arbitrary dimension and mixedness using geometric
entanglement witnesses. These witnesses are constructed using properties of the
Hilbert-Schmidt geometry and can be shifted along parameterized lines. The
involved conditions are simplified using Bloch decompositions of operators and
states. As an example we determine the three different types of states for a
family of two-qutrit states that is part of the "magic simplex", i.e. the set
of Bell-state mixtures of arbitrary dimension.


title:
A Thin Electromagnetic Absorber for Wide Incidence Angles and Both
  Polarizations

abstract:
  In this paper a planar electromagnetic absorber is introduced whose
performance is maintained over a wide change of the incidence angle for both TE
and TM polarization. The absorber comprises an array of patches over a grounded
dielectric slab, with clear advantage in terms of manufacturability. It is
shown that a high value of the relative permittivity of the substrate is
essential for the operation of the absorber. The main contribution of the paper
is to demonstrate and practically use the presence of an additional resonance
of high-impedance surfaces when the plasma frequency of the wire medium
comprising metallic vias in the dielectric substrate is close to the original
resonance of the high-impedance surface. The presence of the vias between FSS
and the ground plane is discussed both for the case of a high-permittivity
absorber and for a low permittivity one. The radius of the vias influences the
oblique incidence TM absorption, and when properly designed, the insertion of
the vias result in bandwidth enlargement and higher absorption.


title: Concentration of the ratio between the geometric and arithmetic means

abstract:
  We explore the concentration properties of the ratio between the geometric
mean and the arithmetic mean, showing that for certain sequences of weights one
does obtain concentration, around a value that depends on the sequence.


title:
Cooling a mechanical resonator via coupling to a tunable double quantum
  dot

abstract:
  We study the cooling of a mechanical resonator (MR) that is capacitively
coupled to a double quantum dot (DQD). The MR is cooled by the dynamical
backaction induced by the capacitive coupling between the DQD and the MR. The
DQD is excited by a microwave field and afterwards a tunneling event results in
the decay of the excited state of the DQD. An important advantage of this
system is that both the energy level splitting and the decay rate of the DQD
can be well tuned by varying the gate voltage. We find that the steady average
occupancy, below unity, of the MR can be achieved by changing both the decay
rate of the excited state and the detuning between the transition frequency of
the DQD and the microwave frequency, in analogy to the laser sideband cooling
of an atom or trapped ion in atomic physics. Our results show that the cooling
of the MR to the ground state is experimentally implementable.


title: Mock Theta Functions

abstract:
  In this Ph.D. thesis, written under the direction of D.B. Zagier and R.W.
Bruggeman, we study the mock theta functions, that were introduced by
Ramanujan. We show how they can be interpreted in the theory of (real-analytic)
modular forms. In Chapter 1 we give results for Lerch sums (also called Appell
functions, or generalized Lambert series). In Chapter 2 we consider indefinite
theta functions of type (r-1,1). Chapter 3 deals with Fourier coefficients of
meromorphic Jacobi forms. In Chapter 4 we use the results from Chapter 2 to
give explicit results for 8 of the 10 fifth order mock theta functions and all
3 seventh order functions, that were originally defined by Ramanujan. The
result is that we can find a correction term, which is a period integral of a
weight 3/2 unary theta functions, such that if we add it to the mock theta
function, we get a weight 1/2 real-analytic modular form, which is annihilated
by the hyperbolic Laplacian.


title: Identities for the Hankel transform and their applications

abstract:
  In the present paper the authors show that iterations of the Hankel transform
with $\mathscr{K}_{\nu}$-transform is a constant multiple of the Widder
transform. Using these iteration identities, several Parseval-Goldstein type
theorems for these transforms are given. By making use of these results a
number of new Goldstein type exchange identities are obtained for these and the
Laplace transform. The identities proven in this paper are shown to give rise
to useful corollaries for evaluating infinite integrals of special functions.
Some examples are also given as illustration of the results presented here.


title: Paradigms-Shift in Set Theory

abstract:
  In this article the author claims that there is a paradigm shift from ZFC to
NFUM and further to NACT - due to philosophical reasons, not mathematical ones.
The goal is to construct systems where every "Not-Properclass" is a set! With
help of Non-Monotonic Logic, the consistent systems NACT-MoonW, NACT*W, and
NACT-SunW are producing "largest possible universes" of sets. Using
self-evident philosophical principles, three approximations are suggested:
NACT+NFUM-closed (to NACT*), NACT&ZFC4+(GCH) (also to NACT*) and NACT-NFUM (to
NACT-Sun). Also the system NACT[&ZFC4-closed]+(FCA) is considered.
  NFUM = NFU with (AC) and measurable properclass Ord. NFUM-closed is NFUM
where the set-constituting formulas Ai in the set operator need not only to be
stratified but also to be made parameter-free (i.e., have only x as free
variable over which the set is comprehended). In other formulas, free variables
are allowed. Keywords: Set Theory, ZFC, Naive Set Theory, Predicate-Extension,
Church Schema of Comprehension, NF, NFUM, Stratification, Universal Sets,
Eliminative Class Theory, NBG, NACT (= Naive Axiomatic Class Theory), NACT-Sun,
NACT-Moon, NACT-Star, NACT+NFUM-closed, ZFCK, NACT+NFUM, (GCH), (FCA) [= Finite
or Countable Anti-Thesis], NACT+ZFC4+(GCH), NACT[+ZFC4-[closed]+(FCA).


title: Cosmological Expansion Started from the Big Bounce on Local Rotation

abstract:
  The cosmological models in the frame of the Newtonian and general
relativistic treatments are considered. The centrifugal forces acting between
particles rotating randomly around each other are shown to be able to reverse
gravitational collapse.


title: Complex and Adaptive Dynamical Systems: A Primer

abstract:
  An thorough introduction is given at an introductory level to the field of
quantitative complex system science, with special emphasis on emergence in
dynamical systems based on network topologies. Subjects treated include graph
theory and small-world networks, a generic introduction to the concepts of
dynamical system theory, random Boolean networks, cellular automata and
self-organized criticality, the statistical modeling of Darwinian evolution,
synchronization phenomena and an introduction to the theory of cognitive
systems.
  It inludes chapter on Graph Theory and Small-World Networks, Chaos,
Bifurcations and Diffusion, Complexity and Information Theory, Random Boolean
Networks, Cellular Automata and Self-Organized Criticality, Darwinian
evolution, Hypercycles and Game Theory, Synchronization Phenomena and Elements
of Cognitive System Theory.


title:
Poincar\'e series and monodromy of the simple and unimodal boundary
  singularities

abstract:
  A boundary singularity is a singularity of a function on a manifold with
boundary. The simple and unimodal boundary singularities were classified by V.
I. Arnold and V. I. Matov. The McKay correspondence can be generalized to the
simple boundary singularities. We consider the monodromy of the simple,
parabolic, and exceptional unimodal boundary singularities. We show that the
characteristic polynomial of the monodromy is related to the Poincar\'e series
of the coordinate algebra of the ambient singularity.


title:
An instance of umbral methods in representation theory: the parking
  function module

abstract:
  We test the umbral methods introduced by Rota and Taylor within the theory of
representation of symmetric group. We define a simple bijection between the set
of all parking functions of length $n$ and the set of all noncrossing
partitions of $\{1,2,...,n\}$. Then we give an umbral expression of the
Frobenius characteristic of the parking function module introduced by Haiman
that allows an explicit relation between this symmetric function and the volume
polynomial of Pitman and Stanley.


title: Physics Beyond the Standard Model

abstract: We review our expectations in the last year before the LHC commissioning.


title: A simplex of bound entangled multipartite qubit states

abstract:
  We construct a simplex for multipartite qubit states of even number n of
qubits, which has the same geometry concerning separability, mixedness, kind of
entanglement, amount of entanglement and nonlocality as the bipartite qubit
states. We derive the entanglement of the class of states which can be
described by only three real parameters with the help of a multipartite measure
for all discrete systems. We prove that the bounds on this measure are optimal
for the whole class of states and that it reveals that the states possess only
n-partite entanglement and not e.g. bipartite entanglement. We then show that
this n-partite entanglement can be increased by stochastic local operations and
classical communication to the purest maximal entangled states. However, pure
n-partite entanglement cannot be distilled, consequently all entangled states
in the simplex are n-partite bound entangled. We study also Bell inequalities
and find the same geometry as for bipartite qubits. Moreover, we show how the
(hidden) nonlocality for all n-partite bound entangled states can be revealed.


title: The distribution of quantum fidelities

abstract:
  When applied to different input states, an imperfect quantum operation yields
output states with varying fidelities, defined as the absolute square of their
overlap with the desired states. We present an expression for the distribution
of fidelities for a class of operations applied to a general qubit state, and
we present general expressions for the variance and input-space averaged
fidelities of arbitrary linear maps on finite dimensional Hilbert spaces.


title: TEST - The Tautenburg Exoplanet Search Telescope

abstract:
  The Tautenburg Exoplanet Search Telescope (TEST) is a robotic telescope
system. The telescope uses a folded Schmidt Camera with a 300mm main mirror.
The focal length is 940mm and it gives a 2.2 square degree field of view. Dome,
mount, and CCD cameras are controlled by a software bundle made by Software
Bisque. The automation of the telescope includes selection of the night
observing program from a given framework, taking darks and skyflats, field
identification, guiding, data taking, and archiving. For the search for
transiting exoplanets and variable stars an automated psf photometry based on
IRAF and a lightcurve analysis based on ESO-Midas are conducted. The images and
the results are managed using a PostgreSQL database.


title: Absence of the Rashba effect in undoped asymmetric quantum wells

abstract:
  To an electron moving in free space an electric field appears as a magnetic
field which interacts with and can reorient the electron spin. In semiconductor
quantum wells this spin-orbit interaction seems to offer the possibility of
gate-voltage control in spintronic devices but, as the electrons are subject to
both ion-core and macroscopic structural potentials, this over-simple picture
has lead to intense debate. For example, an externally applied field acting on
the envelope of the electron wavefunction determined by the macroscopic
potential, underestimates the experimentally observed spin-orbit field by many
orders of magnitude while the Ehrenfest theorem suggests that it should
actually be zero. Here we challenge, both experimentally and theoretically, the
widely held belief that any inversion asymmetry of the macroscopic potential,
not only electric field, will produce a significant spin-orbit field for
electrons. This conclusion has far-reaching consequences for the design of
spintronic devices while illuminating important fundamental physics.


title:
Error-Correcting Codes in Projective Spaces via Rank-Metric Codes and
  Ferrers Diagrams

abstract:
  Coding in the projective space has received recently a lot of attention due
to its application in network coding. Reduced row echelon form of the linear
subspaces and Ferrers diagram can play a key role for solving coding problems
in the projective space. In this paper we propose a method to design
error-correcting codes in the projective space. We use a multilevel approach to
design our codes. First, we select a constant weight code. Each codeword
defines a skeleton of a basis for a subspace in reduced row echelon form. This
skeleton contains a Ferrers diagram on which we design a rank-metric code. Each
such rank-metric code is lifted to a constant dimension code. The union of
these codes is our final constant dimension code. In particular the codes
constructed recently by Koetter and Kschischang are a subset of our codes. The
rank-metric codes used for this construction form a new class of rank-metric
codes. We present a decoding algorithm to the constructed codes in the
projective space. The efficiency of the decoding depends on the efficiency of
the decoding for the constant weight codes and the rank-metric codes. Finally,
we use puncturing on our final constant dimension codes to obtain large codes
in the projective space which are not constant dimension.


title: RE J1034+396: The origin of the soft X-ray excess and QPO

abstract:
  The X-ray quasi-periodic oscillation (QPO) seen in RE J1034+396 is so far
unique amongst AGN. Here we look at the another unique feature of RE J1034+396,
namely its huge soft X-ray excess, to see if this is related in any way to the
detection of the QPO. We show that all potential models considered for the soft
energy excess can fit the 0.3-10 keV X-ray spectrum, but that the energy
dependence of the rapid variability (which is dominated by the QPO) strongly
supports a spectral decomposition where the soft excess is from low temperature
Comptonization of the disc emission and remains mostly constant, while the
rapid variability is produced by the power law tail changing in normalization.
The presence of the QPO in the tail rather than in the disc is a common feature
in black hole binaries, but low temperature Comptonization of the disc spectrum
is not generally seen in these systems. The main exception to this is GRS
1915+105, the only black hole binary which routinely shows super-Eddington
luminosities. We speculate that super-Eddington accretion rates lead to a
change in disc structure, and that this also triggers the X-ray QPO.


title: Groupoid sheaves as quantale sheaves

abstract:
  Several notions of sheaf on various types of quantale have been proposed and
studied in the last twenty five years. It is fairly standard that for an
involutive quantale Q satisfying mild algebraic properties the sheaves on Q can
be defined to be the idempotent self-adjoint Q-valued matrices. These can be
thought of as Q-valued equivalence relations, and, accordingly, the morphisms
of sheaves are the Q-valued functional relations. Few concrete examples of such
sheaves are known, however, and in this paper we provide a new one by showing
that the category of equivariant sheaves on a localic etale groupoid G (the
classifying topos of G) is equivalent to the category of sheaves on its
involutive quantale O(G). As a means towards this end we begin by replacing the
category of matrix sheaves on Q by an equivalent category of complete Hilbert
Q-modules, and we approach the envisaged example where Q is an inverse quantal
frame O(G) by placing it in the wider context of stably supported quantales, on
one hand, and in the wider context of a module theoretic description of
arbitrary actions of \'etale groupoids, both of which may be interesting in
their own right.


title:
Directed transport in a spatially periodic potential under periodic
  non-biased forcing

abstract:
  Transport of a particle in a spatially periodic harmonic potential under the
influence of a slowly time-dependent unbiased periodic external force is
studied. The equations of motion are the same as in the problem of a slowly
forced nonlinear pendulum. Using methods of the adiabatic perturbation theory
we show that for a periodic external force of general kind the system
demonstrates directed (ratchet) transport in the chaotic domain on very long
time intervals and obtain a formula for the average velocity of this transport.
Two cases are studied: the case of the external force of small amplitude, and
the case of the external force with amplitude of order one. The obtained
formulas can also be used in case of a non-harmonic periodic potential.


title: On interpretations of bounded arithmetic and bounded set theory

abstract:
  In a recent paper, Kaye and Wong proved the following result, which they
considered to belong to the folklore of mathematical logic.
  THEOREM: The first-order theories of Peano arithmetic and ZF with the axiom
of infinity negated are bi-interpretable: that is, they are mutually
interpretable with interpretations that are inverse to each other.
  In this note, I describe a theory of sets that stands in the same relation to
the bounded arithmetic IDelta0 + exp. Because of the weakness of this theory of
sets, I cannot straightforwardly adapt Kaye and Wong's interpretation of
arithmetic in set theory. Instead, I am forced to produce a different
interpretation.


title:
Preparation and detection of states with simultaneous spin alignment and
  molecular orientation in PbO

abstract:
  We are pursuing an experiment to measure the electric dipole moment of the
electron using the molecule PbO. This measurement requires the ability to
prepare quantum states with orientation of the molecular axis and,
simultaneously, alignment of the electron spin perpendicular to this axis. It
also requires efficient detection of the evolution of the spin alignment
direction within such a state. We describe a series of experiments that have
achieved these goals, and the features and limitations of the techniques. We
also discuss possible new approaches for improved efficiency in this and
similar systems.


title: Parametric high resolution techniques for radio astronomical imaging

abstract:
  The increased sensitivity of future radio telescopes will result in
requirements for higher dynamic range within the image as well as better
resolution and immunity to interference. In this paper we propose a new matrix
formulation of the imaging equation in the cases of non co-planar arrays and
polarimetric measurements. Then we improve our parametric imaging techniques in
terms of resolution and estimation accuracy. This is done by enhancing both the
MVDR parametric imaging, introducing alternative dirty images and by
introducing better power estimates based on least squares, with positive
semi-definite constraints. We also discuss the use of robust Capon beamforming
and semi-definite programming for solving the self-calibration problem.
Additionally we provide statistical analysis of the bias of the MVDR beamformer
for the case of moving array, which serves as a first step in analyzing
iterative approaches such as CLEAN and the techniques proposed in this paper.
Finally we demonstrate a full deconvolution process based on the parametric
imaging techniques and show its improved resolution and sensitivity compared to
the CLEAN method.


title: The V/S test of long-range dependence in random fields

abstract:
  Recently, Giraitis et al. (2003, [10]) proposed the $V/S$ statistic for
testing long memory in random sequences. We generalize this statistic to the
setting of random fields. The null hypothesis is concerned with short memory
random fields while the alternative contains a very large family of long memory
random fields. Contrary to most of the previous works dealing with long-range
dependence, no assumption is made about the isotropy of the strong dependence.
Some simulations are presented in order to assess the power of the test
according to the kind of long memory in presence.


title: Optimisation of multifractal analysis using box-size scaling

abstract:
  We study various box-size scaling techniques to obtain the multifractal
properties, in terms of the singularity spectrum f(alpha), of the critical
eigenstates at the metal-insulator transition within the 3-D Anderson model of
localisation. The typical and ensemble averaged scaling laws of the generalised
inverse participation ratios are considered. In pursuit of a numerical
optimisation of the box-scaling technique we discuss different box-partitioning
schemes including cubic and non-cubic boxes, use of periodic boundary
conditions to enlarge the system and single and multiple origins for the
partitioning grid are also implemented. We show that the numerically most
reliable method is to divide a system of linear size L equally into cubic boxes
of size l for which L/l is an integer. This method is the least numerically
expensive while having a good reliability.


title: Hodge Correlators II

abstract:
  We define Hodge correlators for a compact Kahler manifold X. They are complex
numbers which can be obtained by perturbative series expansion of a certain
Feynman integral which we assign to X. We show that they define a functorial
real mixed Hodge structure on the rational homotopy type of X.
  The Hodge correlators provide a canonical linear map from the cyclic homomogy
of the cohomology algebra of X to the complex numbers.
  If X is a regular projective algebraic variety over a field k, we define,
assuming the motivic formalism, motivic correlators of X. Given an embedding of
k into complex numbers, their periods are the Hodge correlators of the obtained
complex manifold.
  Motivic correlators lie in the motivic coalgebra of the field k. They come
togerther with an explicit formula for their coproduct in the motivic Lie
coalgebra.


title:
What does really mean the "barrier distribution function" derived from
  backward angle quasi-elastic scattering

abstract:
  The so called "barrier distribution" derived from quasi-elastic
backscattering of heavy ions gives us, in fact, an information about the
"reaction threshold distribution". For light nuclear systems these
distributions are quite close, but for heavy ones (when interaction of nuclei
becomes more and more complicated and the potential barrier can disappear at
all) they may significantly differ. The same should hold also for weakly bound
neutron rich projectiles, for which the neutron transfer and break-up reaction
channels play an important role at near-barrier energies. This is not a
terminology problem but important finding, because experiments on measurement
of the backward angle quasi-elastic scattering for deriving the "barrier
distributions" for heavy nuclear systems (which may be used for the production
of superheavy elements) are planned to be performed in several laboratories.


title: Complex vector fields and hypoelliptic partial differential operators

abstract:
  We prove a subelliptic estimate for systems of complex vector fields under
some assumptions that generalize the essential pseudoconcavity for $CR$
manifolds and H\"ormander's bracket condition for real vector fields.
Applications are given to prove the hypoellipticity of first order systems and
second order partial differential operators. Finally we describe a class of
compact homogeneous CR manifolds for which the distribution of $(0,1)$ vector
fields satisfies a subelliptic estimate. v2: minor revision, to appear in Ann.
Inst. Fourier


title: Construction of weakly CUD sequences for MCMC sampling

abstract:
  In Markov chain Monte Carlo (MCMC) sampling considerable thought goes into
constructing random transitions. But those transitions are almost always driven
by a simulated IID sequence. Recently it has been shown that replacing an IID
sequence by a weakly completely uniformly distributed (WCUD) sequence leads to
consistent estimation in finite state spaces. Unfortunately, few WCUD sequences
are known. This paper gives general methods for proving that a sequence is
WCUD, shows that some specific sequences are WCUD, and shows that certain
operations on WCUD sequences yield new WCUD sequences. A numerical example on a
42 dimensional continuous Gibbs sampler found that some WCUD inputs sequences
produced variance reductions ranging from tens to hundreds for posterior means
of the parameters, compared to IID inputs.


title: Adaptive complexity regularization for linear inverse problems

abstract:
  We tackle the problem of building adaptive estimation procedures for
ill-posed inverse problems. For general regularization methods depending on
tuning parameters, we construct a penalized method that selects the optimal
smoothing sequence without prior knowledge of the regularity of the function to
be estimated. We provide for such estimators oracle inequalities and optimal
rates of convergence. This penalized approach is applied to Tikhonov
regularization and to regularization by projection.


title: Drug-therapy networks and the predictions of novel drug targets

abstract:
  Recently, a number of drug-therapy, disease, drug, and drug-target networks
have been introduced. Here we suggest novel methods for network-based
prediction of novel drug targets and for improvement of drug efficiency by
analysing the effects of drugs on the robustness of cellular networks.


title:
Nucleon to Pion Transition Distribution Amplitudes in a Light-Cone Quark
  Model

abstract:
  We present a general representation for the nucleon distribution amplitudes
and for the nucleon to pion transition distribution amplitudes in terms of
light-cone wave functions. We apply our formalism to a light-cone constituent
quark model giving some numerical results for both the classes of observables.


title:
Functional principal components analysis via penalized rank one
  approximation

abstract:
  Two existing approaches to functional principal components analysis (FPCA)
are due to Rice and Silverman (1991) and Silverman (1996), both based on
maximizing variance but introducing penalization in different ways. In this
article we propose an alternative approach to FPCA using penalized rank one
approximation to the data matrix. Our contributions are four-fold: (1) by
considering invariance under scale transformation of the measurements, the new
formulation sheds light on how regularization should be performed for FPCA and
suggests an efficient power algorithm for computation; (2) it naturally
incorporates spline smoothing of discretized functional data; (3) the
connection with smoothing splines also facilitates construction of
cross-validation or generalized cross-validation criteria for smoothing
parameter selection that allows efficient computation; (4) different smoothing
parameters are permitted for different FPCs. The methodology is illustrated
with a real data example and a simulation.


title: On the low energy brane/anti-brane dynamics

abstract:
  We study the dynamical behavior of a pair of Dp-brane and anti Dp-brane ($0
\leq p \leq 6$) moving parallel to each other in the region where the brane and
anti-brane annihilation will not occur and the low energy description is valid.
Given this, we perform a general analysis, in the center of mass frame, of the
behavior of the effective potential with respect to the relative brane
separation and find that the classical orbits of this system are in general
unbound except for $p = 6$ case for which classical bound orbits exist. The
non-linearity of the low energy DBI action for D-brane is important for the
underlying dynamics. We solve also the explicit orbits for $p = 6$ case.


title:
Hierarchical pinning model with site disorder: Disorder is marginally
  relevant

abstract:
  We study a hierarchical disordered pinning model with site disorder for
which, like in the bond disordered case [6, 9], there exists a value of a
parameter b (enters in the definition of the hierarchical lattice) that
separates an irrelevant disorder regime and a relevant disorder regime. We show
that for such a value of b the critical point of the disordered system is
different from the critical point of the annealed version of the model. The
proof goes beyond the technique used in [9] and it takes explicitly advantage
of the inhomogeneous character of the Green function of the model.


title: Coherent switching by detuning a side-coupled quantum-dot system

abstract:
  We investigate phase coherent electronic transport in an open quantum system,
which consists of quantum dots side-coupled to a nanowire. It is demonstrated
that coherent switching can be characterized by adjusting the electronic
energy. A comparative analysis of quantum coherence effects in side-coupled
quantum-dot systems is presented. Our results demonstrate the relevance of
electronic nanodevices based on coherent switching by appropriately detuning
the side-coupled quantum dots that are located at variable distance along a
wire.


title:
The Breakdown of Linear Elastic Fracture Mechanics near the Tip of a
  Rapid Crack

abstract:
  We present high resolution measurements of the displacement and strain fields
near the tip of a dynamic (Mode I) crack. The experiments are performed on
polyacrylamide gels, brittle elastomers whose fracture dynamics mirror those of
typical brittle amorphous materials. Over a wide range of propagation
velocities ($0.2-0.8c_s$), we compare linear elastic fracture mechanics (LEFM)
to the measured near-tip fields. We find that, sufficiently near the tip, the
measured stress intensity factor appears to be non-unique, the crack tip
significantly deviates from its predicted parabolic form, and the strains ahead
of the tip are more singular than the $r^{-1/2}$ divergence predicted by LEFM.
These results show how LEFM breaks down as the crack tip is approached.


title:
LRS Bianchi Type I Models with Anisotropic Dark Energy and Constant
  Deceleration Parameter

abstract:
  Locally rotationally symmetric (LRS) Bianchi Type I cosmological models are
examined in the presence of dynamically anisotropic dark energy and perfect
fluid. We assume that the dark energy (DE) is minimally interacting, has
dynamical energy density, anisotropic equation of state parameter (EoS). The
conservation of the energy-momentum tensor of the DE is assumed to consist of
two separately additive conserved parts. A special law is assumed for the
deviation from isotropic EoS, which is consistent with the assumption on the
conservation of the energy-momentum tensor of the DE. Exact solutions of
Einstein's field equations are obtained by assuming a special law of variation
for the mean Hubble parameter, which yields a constant value of the
deceleration parameter. Geometrical and kinematic properties of the models and
the behaviour of the anisotropy of the dark energy has been carried out. The
models give dynamically anisotropic expansion history for the universe that
allows to fine tune the isotropization of the Bianchi metric, hence the CMB
anisotropy.


title: Weakly Nonlinear Theory of Dynamic Fracture

abstract:
  The common approach to crack dynamics, linear elastic fracture mechanics
(LEFM), assumes infinitesimal strains and predicts a $r^{-1/2}$ strain
divergence at a crack tip. We extend this framework by deriving a weakly
nonlinear fracture mechanics theory incorporating the leading nonlinear elastic
corrections that must occur at high strains. This yields strain contributions
"more-divergent" than $r^{-1/2}$ at a finite distance from the tip and
logarithmic corrections to the parabolic crack tip opening displacement. In
addition, a dynamic length-scale, associated with the nonlinear elastic zone,
emerges naturally. The theory provides excellent agreement with recent near-tip
measurements that can not be described in the LEFM framework.


title:
New study of shot noise with the nonequilibrium Kubo formula in
  mesoscopic systems, application to the Kondo effect at a quantum dot

abstract:
  Recently we have developed a theory of Keldysh formalism for mesoscopic
systems. The resulting nonequilibrium Kubo formula for differential conductance
makes it possible to propose the new formula of shot noise $S_h$, and thus to
study shot noise in correlated systems at any temperature and any bias voltage.
Employing this new approach, we analyze shot noise in the Kondo regime through
a quantum dot for the symmetric case at zero temperature. Using the
renormalized perturbation theory, we prove that in the leading order of bias
voltage $S_h$ equal to noise power at zero temperature conventionally used as
shot noise. With $S_h$, we calculate the Fano factor for a backscattering
current $I_b$: $F_b=S_h/2eI_b$. It is shown that the Fano factor takes the
universal form of $F_b=1+4(R-1)^2/(1+5(R-1)^2)$ determined by the Wilson ratio
$R$ for arbitrary strength of the Coulomb interaction. Using the Wilson ratio
R=2, our result coincides with the fractional value of $F_b=5/3$ already
derived in the Kondo regime.


title: Tidal dissipation in binary systems

abstract:
  To first approximation, a binary system conserves its angular momentum while
it evolves to its state of minimum kinetic energy: circular orbit, all spins
aligned, and components rotating in synchronism with the orbital motion. The
pace at which this final state is achieved depends on the physical processes
that are responsible for the dissipation of the tidal kinetic energy. For stars
(or planets) with an outer convection zone, the dominant mechanism identified
so far is the viscous dissipation acting on the equilibrium tide. For stars
with an outer radiation zone, it is the radiative damping operating on the
dynamical tide. After a brief presentation of the tides, I shall review these
physical processes; I shall discuss the uncertainties of their present
treatment, describe the latest developments, and compare the theoretical
predictions with the observed properties concerning the orbital circularization
of close binaries.


title: The Pierre Auger Observatory: Results on Ultra-High Energy Cosmic Rays

abstract:
  The focus of this article is on recent results on ultra-high energy cosmic
rays obtained with the Pierre Auger Observatory. The world's largest instrument
of this type and its performance are described. The observations presented here
include the energy spectrum, the primary particle composition, limits on the
fluxes of photons and neutrinos and a discussion of the anisotropic
distribution of the arrival directions of the most energetic particles.
Finally, plans for the construction of a Northern Auger Observatory in
Colorado, USA, are discussed.


title:
Lattice and Magnetic structures of PrFeAsO, PrFeAsO0.85F0.15 and
  PrFeAsO0.85

abstract:
  We use powder neutron diffraction to study the spin and lattice structures of
polycrystalline samples of nonsuperconducting PrFeAsO and superconducting
PrFeAsO0.85F0.15 and PrFeAsO0.85. We find that PrFeAsO exhibits an abrupt
structural phase transitions at 153 K, followed by static long range
antiferromagnetic order at 127 K. Both the structural distortion and magnetic
order are identical to other rare-earth oxypnictides. Electron-doping the
system with either Fluorine or oxygen deficiency suppresses the structural
distortion and static long range antiferromagnetic order, therefore placing
these materials into the same class of FeAs-based superconductors.


title: Flow Equations for the Ionic Hubbard Model

abstract:
  Taking the site-diagonal terms of the one-dimensional ionic Hubbard model
(IHM) as $H_0$, we employ Continuous Unitary Transformations (CUT) to obtain a
"classical" effective Hamiltonian in which hopping term has been integrated
out. For this Hamiltonian spin gap and charge gap are calculated at
half-filling and subject to periodic boundary conditions. Our calculations
indicate two transition points. In fixed $\Delta$, as $U$ increases from zero,
there is a region in which both spin gap and charge gap are positive and
identical; characteristic of band insulators. Upon further increasing $U$,
first transition occurs at $U=U_{c_{1}}$, where spin and charge gaps both
vanish and remain zero up to $U=U_{c_{2}}$. A gap-less state in charge and spin
sectors characterizes a metal. For $U>U_{c_{2}}$ spin gap remains zero and
charge gap becomes positive. This third region corresponds to a Mott insulator
in which charge excitations are gaped, while spin excitations remain gap-less.


title: Canonical Relativity and the Dimensionality of the World

abstract:
  Different aspects of relativity, mainly in a canonical formulation, relevant
for the question "Is spacetime nothing more than a mathematical space (which
describes the evolution in time of the ordinary three-dimensional world) or is
it a mathematical model of a real four-dimensional world with time entirely
given as the fourth dimension?" are presented. The availability as well as
clarity of the arguments depend on which framework is being used, for which
currently special relativity, general relativity and some schemes of quantum
gravity are available. Canonical gravity provides means to analyze the field
equations as well as observable quantities, the latter even in coordinate
independent form. This allows a unique perspective on the question of
dimensionality since the space-time manifold does not play a prominent role.
After re-introducing a Minkowski background into the formalism, one can see how
distinguished coordinates of special relativity arise, where also the nature of
time is different from that in the general perspective. Just as it is of
advantage to extend special to general relativity, general relativity itself
has to be extended to some theory of quantum gravity. This suggests that a
final answer has to await a thorough formulation and understanding of a
fundamental theory of space-time. Nevertheless, we argue that current insights
into quantum gravity do not change the picture of the role of time obtained
from general relativity.


title: Spin(7)-manifolds with parallel torsion form

abstract:
  Any Spin(7)-manifold admits a metric connection \nabla^c with totally
skew-symmetric torsion T^c preserving the underlying structure. We classify
those with \nabla^c-parallel T^c\neq0 and non-Abelian isotropy algebra
iso(T^c)<spin(7). These are isometric to either Riemannian products or
homogeneous naturally reductive spaces, each admitting two \nabla^c-parallel
spinor fields.


title:
Coexistence of static magnetism and superconductivity in SmFeAsO1-xFx as
  revealed by muon spin rotation

abstract:
  The recent observation of superconductivity with critical temperatures up to
55 K in the FeAs based pnictide compounds marks the first discovery of a non
copper-oxide based layered high-Tc superconductor (HTSC) [1-3]. It has raised
the suspicion that these new materials share a similar pairing mechanism to the
cuprates, since both exhibit superconductivity following charge doping of a
magnetic parent material. Here we present a muon spin rotation study on
SmFeAsO1-xFx (x=0-0.30), which shows that static magnetism persists well into
the superconducting regime. The analogy with the cuprates is quite surprising
since the parent compounds appear to have different magnetic ground states:
itinerant spin density wave for the pnictides contrasted with the Mott-Hubbard
insulator in the cuprates. Our findings suggest that proximity to magnetic
order and associated soft magnetic fluctuations, rather than the strong
electronic correlations in the vicinity of a Mott-Hubbard-metal-to-insulator
transition, may be the key ingredients of HTSC.


title: Rank and crank moments for overpartitions

abstract:
  We study two types of crank moments and two types of rank moments for
overpartitions. We show that the crank moments and their derivatives, along
with certain linear combinations of the rank moments and their derivatives, can
be written in terms of quasimodular forms. We then use this fact to prove exact
relations involving the moments as well as congruence properties modulo 3, 5,
and 7 for some combinatorial functions which may be expressed in terms of the
second moments. Finally, we establish a congruence modulo 3 involving one such
combinatorial function and the Hurwitz class number H(n).


title: Introduction to Hubbard Model and Exact Diagonalization

abstract:
  Hubbard model is an important model in theory of strongly correlated electron
systems. In this contribution we introduce this model along with numerically
exact method of diagonalization of the model.


title: FDR control for multiple hypothesis testing on composite nulls

abstract:
  Multiple hypothesis testing often involves composite nulls, i.e., nulls that
are associated with two or more distributions. In many cases, it is reasonable
to assume that there is a prior distribution on the distributions despite it is
unknown. When the number of distributions under true nulls is finite, we show
that under the above assumption, the false discover rate (FDR) can be
controlled using $p$-values computed under constraints imposed by the empirical
distribution of the observations. Comparing to FDR control using $p$-values
defined as maximum significance level over all null distributions, the proposed
FDR control can have substantially more power.


title: Is the Universe More Transparent to Gamma Rays Than Previously Thought?

abstract:
  The MAGIC collaboration has recently reported the detection of the strong
gamma-ray blazar 3C279 during a 1-2 day flare. They have used their spectral
observations to draw conclusions regarding upper limits on the opacity of the
Universe to high energy gamma-rays and, by implication, upper limits on the
extragalactic mid-infrared background radiation. In this paper we examine the
effect of gamma-ray absorption by the extragalactic infrared radiation on
intrinsic spectra for this blazar and compare our results with the
observational data on 3C279. We find agreement with our previous results,
contrary to the recent assertion of the MAGIC group that the Universe is more
transparent to \gray s than our calculations indicate. Our analysis indicates
that in the energy range between ~80 and ~500 GeV, 3C279 has a best-fit
intrinsic spectrum with a spectral index ~1.78 using our fast evolution model
and ~2.19 using our baseline model. However, we also find that spectral indices
in the range of 0.0 to 3.0 are almost as equally acceptable as the best fit
spectral indices. Assuming the same intrinsic spectral index for this flare as
for the 1991 flare from 3C279 observed by EGRET, viz., 2.02, which lies between
our best fit indices, we estimate that the MAGIC flare was ~3 times brighter
than the EGRET flare observed 15 years earlier.


title: Capacity and Performance of Adaptive MIMO System Based on Beam-Nulling

abstract:
  In this paper, we propose a scheme called "beam-nulling" for MIMO adaptation.
In the beam-nulling scheme, the eigenvector of the weakest subchannel is fed
back and then signals are sent over a generated subspace orthogonal to the
weakest subchannel. Theoretical analysis and numerical results show that the
capacity of beam-nulling is closed to the optimal water-filling at medium SNR.
Additionally, signal-to-interference-plus-noise ratio (SINR) of MMSE receiver
is derived for beam-nulling. Then the paper presents the associated average
bit-error rate (BER) of beam-nulling numerically which is verified by
simulation. Simulation results are also provided to compare beam-nulling with
beamforming. To improve performance further, beam-nulling is concatenated with
linear dispersion code. Simulation results are also provided to compare the
concatenated beam-nulling scheme with the beamforming scheme at the same data
rate. Additionally, the existing beamforming and new proposed beam-nulling can
be extended if more than one eigenvector is available at the transmitter. The
new extended schemes are called multi-dimensional (MD) beamforming and MD
beam-nulling. Theoretical analysis and numerical results in terms of capacity
are also provided to evaluate the new extended schemes. Simulation results show
that the MD scheme with LDC can outperform the MD scheme with STBC
significantly when the data rate is high.


title: Superconductivity in heavily vacant diamond

abstract:
  Using first principle electronic structure calculations we investigated the
role of substitutional doping of B,N,P,Al and vacancies (${\cal V}$) in diamond
(X$_{\alpha}$C$_{1-\alpha}$). In the heavy doping regime, at about $\sim 1-6%$
doping an impurity band appears in the mid gap. Increasing further the
concentration of the impurity substitution fills in the gap of the diamond
host. Our first principle calculation indicates that in the case of vacancies,
a clear single-band picture can be employed to write down an effective {\em one
band} microscopic Hamiltonian, which can be used to further study various
many-body and disorder effects in impurity band (super)conductors.


title:
K pi vector form factor, dispersive constraints and tau -> nu_tau K pi
  decays

abstract:
  Recent experimental data for the differential decay distribution of the decay
$\tau^-\to\nu_\tau K_S\pi^-$ by the Belle collaboration are described by a
theoretical model which is composed of the contributing vector and scalar form
factors $F_+^{K\pi}(s)$ and $F_0^{K\pi}(s)$. Both form factors are constructed
such that they fulfil constraints posed by analyticity and unitarity. A good
description of the experimental measurement is achieved by incorporating two
vector resonances and working with a three-times subtracted dispersion relation
in order to suppress higher-energy contributions. The resonance parameters of
the charged $K^*(892)$ meson, defined as the pole of $F_+^{K\pi}(s)$ in the
complex $s$-plane, can be extracted, with the result $M_{K^*}=892.0 \pm 0.9
$MeV and $\Gamma_{K^*}=46.2 \pm 0.4 $MeV. Finally, employing the
three-subtracted dispersion relation allows to determine the slope and
curvature parameters $\lambda_+^{'}=(24.7\pm 0.8)\cdot 10^{-3}$ and
$\lambda_+^{''}=(12.0\pm 0.2)\cdot 10^{-4}$ of the vector form factor
$F_+^{K\pi}(s)$ directly from the data.


title: Stripes, Zigzags, and Slow Dynamics in Buckled Hard Spheres

abstract:
  We study the analogy between buckled colloidal monolayers and the
triangular-lattice Ising antiferromagnet. We calculate free volume-induced
Ising interactions, show how lattice deformations favor zigzag stripes that
partially remove the Ising model ground-state degeneracy, and identify the
Martensitic mechanism prohibiting perfect stripes. Slowly inflating the spheres
yields jamming as well as logarithmically slow relaxation reminiscent of the
glassy dynamics observed experimentally.


title: Conformal invariance and apparent universality of semiclassical gravity

abstract:
  In a recent work, it has been pointed out that certain observables of the
massless scalar field theory in a static spherically symmetric background
exhibit a universal behavior at large distances. More precisely, it was shown
that, unlike what happens in the case the coupling to the curvature \xi is
generic, for the special cases \xi=0 and \xi = 1/6 the large distance behavior
of the expectation value <T^{\mu}_{\nu}> turns out to be independent of the
internal structure of the gravitational source. Here, we address a higher
dimensional generalization of this result: We first compute the difference
between a black hole and a static spherically symmetric star for the
observables <\phi^2> and <T^{\mu}_{\nu}> in the far field limit. Thus, we show
that the conformally invariant massless scalar field theory in a static
spherically symmetric background exhibits such universality phenomenon in D\geq
4 dimensions. Also, using the one-loop effective action, we compute
<T^{\mu}_{\nu}> for a weakly gravitating object. These results lead to the
explicit expression of the expectation value <T^{\mu}_{\nu}> for a
Schwarzschild-Tangherlini black hole in the far field limit. As an application,
we obtain quantum corrections to the gravitational potential in D dimensions,
which for D=4 are shown to agree with the one-loop correction to the graviton
propagator previously found in the literature.


title: UV/IR mixing in noncommutative QED defined by Seiberg-Witten map

abstract:
  Noncommutative gauge theories defined via Seiberg-Witten map have desirable
properties that theories defined directly in terms of noncommutative fields
lack, covariance and unrestricted choice of gauge group and charge being among
them, but nonperturbative results in the deformation parameter \theta are hard
to obtain. In this article we use a \theta-exact approach to study UV/IR mixing
in a noncommutative quantum electrodynamics (NCQED) model defined via
Seiberg-Witten map. The fermion contribution of the one loop correction to the
photon propagator is computed and it is found that it gives the same UV/IR
mixing term as a NCQED model without Seiberg-Witten map.


title: Geometrical interpretation of the Casimir effect

abstract:
  Casimir forces are a manifestation of the change in the zero-point energy of
the vacuum caused by the insertion of boundaries. We show how the Casimir force
can be efficiently computed by consideration of the vacuum fluctuations that
are suppressed by the boundaries, and rederive the scalar Casimir effects for a
series of the Dirichlet geometries. For the planar case a finite universal
force is automatically found. Consistent with other calculations of the effect,
for curved geometries divergent (non-universal) expressions are encountered.
They are interpreted geometrically following Candelas and Deutsch (1979) as
largely due to the divergent self-energy of the boundary contributing to the
force. This viewpoint is supported by explicit calculations for a
wedge-circular arc geometry in two dimensions where non-universal and universal
contributions into the effect can be unambiguously separated. We also give a
heuristic derivation of the purely geometrical expression (Sen, 1981) for the
non-universal piece of the Casimir energy due to an arbitrary smooth
two-dimensional Dirichlet boundary of a compact region.


title: Dihedral Gauss hypergeometric functions

abstract:
  Gauss hypergeometric functions with a dihedral monodromy group can be
expressed as elementary functions, since their hypergeometric equations can be
transformed to Fuchsian equations with cyclic monodromy groups by a quadratic
change of the argument variable. The paper presents general elementary
expressions of these dihedral hypergeometric functions, involving finite
bivariate sums expressible as terminating Appell's F2 or F3 series.
Additionally, trigonometric expressions for the dihedral functions are
presented, and degenerate cases (logarithmic, or with the monodromy group Z/2Z)
are considered.


title: Dynamic Ly alpha jets

abstract:
  The solar chromosphere and transition region are highly structured and
complex regimes. A recent breakthrough has been the identification of dynamic
fibrils observed in H alpha as caused by field-aligned magnetoacoustic shocks.
We seek to find whether such dynamic fibrils are also observed in Ly alpha. We
used a brief sequence of four high-resolution Ly alpha images of the solar limb
taken by the Very high Angular resolution ULtraviolet Telescope (VAULT), which
displays many extending and retracting Ly alpha jets. We measured their top
trajectories and fitted parabolas to the 30 best-defined ones. Most jet tops
move supersonically. Half of them decelerate, sometimes superballistically, the
others accelerate. This bifurcation may arise from incomplete sampling of
recurrent jets. The similarities between dynamic Ly alpha jets and H alpha
fibrils suggest that the magnetoacoustic shocks causing dynamic H alpha fibrils
also affect dynamic Ly alpha jets.


title:
Fermi surface of superconducting LaFePO determined by quantum
  oscillations

abstract:
  We report extensive measurements of quantum oscillations in the normal state
of the Fe-based superconductor LaFePO, (Tc ~ 6 K) using low temperature torque
magnetometry and transport in high static magnetic fields (45 T). We find that
the Fermi surface is in broad agreement with the band-structure calculations
with the quasiparticle mass enhanced by a factor ~2. The quasi-two dimensional
Fermi surface consist of nearly-nested electron and hole pockets, suggesting
proximity to a spin/charge density wave instability.


title: Knots, sutures and excision

abstract:
  We develop monopole and instanton Floer homology groups for balanced sutured
manifolds. Applications include a new proof of Property P for knots.


title:
Three-Dimensional Two-Pion Emission Source at SPS: Extraction of Source
  Breakup Time and Emission Duration

abstract:
  A model-independent, three-dimensional source function for pion pairs has
been extracted from Pb+Pb collisions at $\sqrt s_{NN}=17.3$ AGeV. The extracted
sourc e exhibits long-range non-Gaussian tails in the directions of the
pion-pair net transverse-momentum and of the beam. Comparison with the
Therminator model allow s for an extraction of the pion source proper breakup
time and of emission durat ion in the collisions.


title:
Vector Meson Dominance as a first step in a systematic approximation:
  the pion vector form factor

abstract:
  Pade Approximants can be used to go beyond Vector Meson Dominance in a
systematic approximation. We illustrate this fact with the case of the pion
vector form factor and extract values for the first two coefficients of its
Taylor expansion. Pade Approximants are shown to be a useful and simple tool
for incorporating high-energy information, allowing an improved determination
of these Taylor coefficients.


title: Complex cobordisms and singular manifolds arising from Chern classes

abstract:
  This paper deals with the question of J.Morava on existence of canonical
complex cobordism class of singular submanifold. We present several solutions
of this question for $X_r(\xi)$ -- the set of points where $\dim\xi-r+1$
generic sections of a complex vector bundle $\xi$ are linearly dependent. The
corresponding complex cobordism classes $Q_r(\xi)$ and $P_r(\xi)$ tend to have
many nice properties, such as deformed sum formula, but they don't coincide
with Chern classes $c_r^U(\xi)$. They also have relation to the theory of
$IH$-small resolutions.


title:
Light-like Wilson Loops and Cusp Anomalous Dimensions in Non-conformal
  Gauge Theories

abstract:
  We emphasize that non-conformal theories provide a natural playground for the
ideas of the Maldacena conjecture, opening the possibility of exploring
properties that could potentially be in the same universality class as QCD. In
particular, we discuss in detail how light-like Wilson loops, an important
ingredient in the prescription for scattering amplitudes, can be described in a
number of gravity duals of non-conformal gauge theories. We point out to a few
universal properties and the prominent role of the strong scale.


title:
Seyfert Galaxies in the Local Universe: Analysis of Spitzer Spectra of a
  Complete Sample

abstract:
  The Spitzer high resolution spectra of 72 Seyfert galaxies from the 12$\mu$m
Galaxy Sample are presented and discussed. The presence of starburst components
in these galaxies can be quantified by powerful mid-IR diagnostics tools (i.e.
11.25$\mu$m PAH feature equivalent width and the H$_2$ emission line
intensity), as well as the AGN dominance can be measured by specific fine
structure line ratios (e.g. [NeV]/[NeII], [NeV]/[SiII], etc.). The two types of
Seyfert galaxies do not show any statistical difference in our diagnostic
tools. However, the Seyfert 2's showing hidden Broad Line Regions in
spectro-polarimetric observations have on average an higher AGN dominance, a
weaker star formation component and a warmer [60 - 25] spectral index than
those without broad emission lines.


title: Comment on the Scaling Function in AdS4 x CP3

abstract:
  The folded spinning string in AdS3 gives us an important insight into AdS/CFT
duality. Recently its one-loop energy was analyzed in the context of AdS4/CFT3
by McLoughlin and Roiban arXiv:0807.3965, by Alday, Arutyunov and Bykov
arXiv:0807.4400 and by Krishnan arXiv:0807.4561. They computed the spectrum of
the fluctuations around the classical solution.
  In this paper we reproduce their results using the algebraic curve technique
and show that under some natural resummation of the fluctuation energies the
one-loop energy agrees perfectly with the predictions of arXiv:0807.0777. This
provides a further support of the all-loop Bethe equations and of the AdS4xCP3
algebraic curve developed in arXiv:0807.0437.


title: Random matrices: Universality of ESDs and the circular law

abstract:
  Given an $n \times n$ complex matrix $A$, let
  $$\mu_{A}(x,y):= \frac{1}{n} |\{1\le i \le n, \Re \lambda_i \le x, \Im
\lambda_i \le y\}|$$ be the empirical spectral distribution (ESD) of its
eigenvalues
  $\lambda_i \in \BBC, i=1, ... n$.
  We consider the limiting distribution (both in probability and in the almost
sure convergence sense) of the normalized ESD $\mu_{\frac{1}{\sqrt{n}} A_n}$ of
a random matrix $A_n = (a_{ij})_{1 \leq i,j \leq n}$ where the random variables
$a_{ij} - \E(a_{ij})$ are iid copies of a fixed random variable $x$ with unit
variance. We prove a \emph{universality principle} for such ensembles, namely
that the limit distribution in question is {\it independent} of the actual
choice of $x$. In particular, in order to compute this distribution, one can
assume that $x$ is real of complex gaussian. As a related result, we show how
laws for this ESD follow from laws for the \emph{singular} value distribution
of $\frac{1}{\sqrt{n}} A_n - zI$ for complex $z$. As a corollary we establish
the Circular Law conjecture (in both strong and weak forms), that asserts that
$\mu_{\frac{1}{\sqrt{n}} A_n}$ converges to the uniform measure on the unit
disk when the $a_{ij}$ have zero mean.


title: OP2 bundles in M-theory

abstract:
  Ramond has observed that the massless multiplet of eleven-dimensional
supergravity can be generated from the decomposition of certain representation
of the exceptional Lie group F4 into those of its maximal compact subgroup
Spin(9). The possibility of a topological origin for this observation is
investigated by studying Cayley plane, OP2, bundles over eleven-manifolds Y.
The lift of the topological terms gives constraints on the cohomology of Y
which are derived. Topological structures and genera on Y are related to the
corresponding ones on the total space M. The latter, being 27-dimensional,
might provide a candidate for `bosonic M-theory'. The discussion leads to a
connection with an octonionic version of Kreck-Stolz elliptic homology theory.


title: Search for Second-Class Currents in tau- -> omega pi- nu_tau

abstract:
  We report on an analysis of $\tau^-$ decaying into $\omega\pi^-\nu_\tau$ with
$\omega\to\pi^+\pi^-\pi^0$ using data containing nearly 320 million tau pairs
collected with the BABAR detector at the PEP-II asymmetric energy $B$-Factory.
We find no evidence for second-class currents and set an upper limit at 0.69%
at a 90% confidence level for the ratio of second- to first-class currents.


title:
A Proof of Green's Conjecture Regarding the Removal Properties of Sets
  of Linear Equations

abstract:
  A system of \ell linear equations in p unknowns Mx=b is said to have the
removal property if every set S \subseteq {1,...,n} which contains
o(n^{p-\ell}) solutions of Mx=b can be turned into a set S' containing no
solution of Mx=b, by the removal of o(n) elements. Green [GAFA 2005] proved
that a single homogenous linear equation always has the removal property and
conjectured that every set of homogenous linear equations has the removal
property. We confirm Green's conjecture by showing that every set of linear
equations (even non-homogenous) has the removal property.


title: Dephasing assisted transport: Quantum networks and biomolecules

abstract:
  Transport phenomena are fundamental in Physics. They allow for information
and energy to be exchanged between individual constituents of communication
systems, networks or even biological entities. Environmental noise will
generally hinder the efficiency of the transport process. However, and contrary
to intuition, there are situations in classical systems where thermal
fluctuations are actually instrumental in assisting transport phenomena. Here
we show that, even at zero temperature, transport of excitations across
dissipative quantum networks can be enhanced by local dephasing noise. We
explain the underlying physical mechanisms behind this phenomenon, show that
entanglement does not play a supportive role and propose possible experimental
demonstrations in quantum optics. We argue that Nature may be routinely
exploiting this effect and show that the transport of excitations in light
harvesting molecules does benefit from such noise assisted processes. These
results point towards the possibility for designing optimized structures for
transport, for example in artificial nano-structures, assisted by noise.


title:
A new approach for detecting scientific specialties from raw cocitation
  networks

abstract:
  We use a technique recently developed by Blondel et al. (2008) in order to
detect scientific specialties from author cocitation networks. This algorithm
has distinct advantages over most of the previous methods used to obtain
cocitation "clusters", since it avoids the use of similarity measures, relies
entirely on the topology of the weighted network and can be applied to
relatively large networks. Most importantly, it requires no subjective
interpretation of the cocitation data or of the communities found. Using two
examples, we show that the resulting specialties are the smallest coherent
"group" of researchers (within a hierarchy of cluster sizes) and can thus be
identified unambiguously. Furthermore, we confirm that these communities are
indeed representative of what we know about the structure of a given scientific
discipline and that, as specialties, they can be accurately characterized by a
few keywords (from the publication titles). We argue that this robust and
efficient algorithm is particularly well-suited to cocitation networks, and
that the results generated can be of great use to researchers studying various
facets of the structure and evolution of science.


title:
Random networks with sublinear preferential attachment: Degree
  evolutions

abstract:
  We define a dynamic model of random networks, where new vertices are
connected to old ones with a probability proportional to a sublinear function
of their degree. We first give a strong limit law for the empirical degree
distribution, and then have a closer look at the temporal evolution of the
degrees of individual vertices, which we describe in terms of large and
moderate deviation principles. Using these results, we expose an interesting
phase transition: in cases of strong preference of large degrees, eventually a
single vertex emerges forever as vertex of maximal degree, whereas in cases of
weak preference, the vertex of maximal degree is changing infinitely often.
Loosely speaking, the transition between the two phases occurs in the case when
a new edge is attached to an existing vertex with a probability proportional to
the root of its current degree.


title: Vortex Molecules in Spinor Condensates

abstract:
  Condensates of atoms with spins can have vortices of several types; these are
related to the symmetry group of the atoms' ground state. We discuss how, when
a condensate is placed in a small magnetic field that breaks the spin symmetry,
these vortices may form bound states. Using symmetry classification of
vortex-charge and rough estimates for vortex interactions, one can show that
some configurations that are stable at zero temperature can decay at finite
temperatures by crossing over energy barriers. Our focus is cyclic spin 2
condensates, which have tetrahedral symmetry.


title: Linear-Optical Hyperentanglement-Assisted Quantum Error-Correcting Code

abstract:
  We propose a linear-optical implementation of a hyperentanglement-assisted
quantum error-correcting code. The code is hyperentanglement-assisted because
the shared entanglement resource is a photonic state hyperentangled in
polarization and orbital angular momentum. It is possible to encode, decode,
and diagnose channel errors using linear-optical techniques. The code corrects
for polarization "flip" errors and is thus suitable only for a
proof-of-principle experiment. The encoding and decoding circuits use a
Knill-Laflamme-Milburn-like scheme for transforming polarization and orbital
angular momentum photonic qubits. A numerical optimization algorithm finds a
unit-fidelity encoding circuit that requires only three ancilla modes and has
success probability equal to 0.0097.


title: An Ore-type theorem for perfect packings in graphs

abstract:
  We say that a graph G has a perfect H-packing (also called an H-factor) if
there exists a set of disjoint copies of H in G which together cover all the
vertices of G. Given a graph H, we determine, asymptotically, the Ore-type
degree condition which ensures that a graph G has a perfect H-packing. More
precisely, let \delta_{\rm Ore} (H,n) be the smallest number k such that every
graph G whose order n is divisible by |H| and with d(x)+d(y)\geq k for all
non-adjacent x \not = y \in V(G) contains a perfect H-packing. We determine
\lim_{n\to \infty} \delta_{\rm Ore} (H,n)/n.


title:
Magnetic molecules created by hydrogenation of Polycyclic Aromatic
  Hydrocarbons

abstract:
  Present routes to produce magnetic organic-based materials adopt a common
strategy: the use of magnetic species (atoms, polyradicals, etc.) as building
blocks. We explore an alternative approach which consists of selective
hydrogenation of Polycyclic Aromatic Hydrocarbons. Self-Consistent-Field (SCF)
(Hartree-Fock and DFT) and multi-configurational (CISD and MCSCF) calculations
on coronene and corannulene, both hexa-hydrogenated, show that the formation of
stable high spin species is possible. The spin of the ground states is
discussed in terms of the Hund rule and Lieb's theorem for bipartite lattices
(alternant hydrocarbons in this case). This proposal opens a new door to
magnetism in the organic world.


title:
Study of the process e+e- -> omega pi0 in the phi-meson mass region with
  the KLOE detector

abstract:
  We have studied the e+e- -> omegapi0 cross section in the sqrt(s) interval
1000-1030 MeV using the pi+pi-pi0pi0 and pi0pi0gamma final states with a sample
of ~600 pb^-1 collected with the KLOE detector at DAFNE. By fitting the
observed interference pattern around M_phi for both final states, we extract
the ratio of the decay widths Gamma(omega->pi0gamma)/Gamma(omega->pi+pi-pi0) =
0.0897 +- 0.0016 and derive the branching fractions BR(omega -> pi+pi-pi0)=
(90.24 +- 0.19)%, BR(omega -> pi0gamma) = (8.09 +- 0.14)%. The parameters
describing the e+e- -> omegapi0 reaction around M_\phi are also used to extract
the branching fraction for the OZI and G-parity violating phi -> omegapi0
decay: BR(phi->omegapi0) = (4.4 +- 0.6)x10^-5.


title: Gravitational dynamics in Bose Einstein condensates

abstract:
  Analogue models for gravity intend to provide a framework where matter and
gravity, as well as their intertwined dynamics, emerge from degrees of freedom
that have a priori nothing to do with what we call gravity or matter. Bose
Einstein condensates (BEC) are a natural example of analogue model since one
can identify matter propagating on a (pseudo-Riemannian) metric with collective
excitations above the condensate of atoms. However, until now, a description of
the "analogue gravitational dynamics" for such model was missing. We show here
that in a BEC system with massive quasi-particles, the gravitational dynamics
can be encoded in a modified (semi-classical) Poisson equation. In particular,
gravity is of extreme short range (characterized by the healing length) and the
cosmological constant appears from the non-condensed fraction of atoms in the
quasi-particle vacuum. While some of these features make the analogue
gravitational dynamics of our BEC system quite different from standard
Newtonian gravity, we nonetheless show that it can be used to draw some
interesting lessons about "emergent gravity" scenarios.


title:
Ab initio calculations of the atomic and electronic structure of CaTiO3
  (001) and (011) surfaces

abstract:
  We present the results of calculations of surface relaxations, energetics,
and bonding properties for CaTiO3 (001) and (011) surfaces using a hybrid B3PW
description of exchange and correlation. We consider both CaO and TiO2
terminations of the non-polar (001) surface, and Ca, TiO and O terminations of
the polar (011) surface. On the (001) surfaces, we find that all upper-layer
atoms relax inwards on the CaO-terminated surface, while outward relaxations of
all atoms in the second layer are found for both terminations. For the
TiO2-terminated (001) surface, the largest relaxations are on the second-layer
atoms. The surface rumpling is much larger for the CaO-terminated than for the
TiO2-terminated (001) surface, but their surface energies are quite similar at
0.94eV and 1.13eV respectively. In contrast, different terminations of the
(011) CaTiO3 surface lead to very different surface energies of 1.86eV, 1.91eV,
and 3.13eV for the O-terminated, Ca-terminated, and TiO-terminated (011)
surface respectively. Our results for surface energies contrast sharply with
those of Zhang et al. [Phys. Rev. B 76, 115426 (2007)], where the authors found
a rather different pattern of surface energies. We predict a considerable
increase of the Ti-O chemical bond covalency near the (011) surface as compared
both to the bulk and to the (001) surface.


title: Research Challenges in Management and Compliance of Policies on the Web

abstract:
  In this paper we argue that policies are an increasing concern for
organizations that are operating a web site. Examples of policies that are
relevant in the domain of the web address issues such as privacy of personal
data, accessibility for the disabled, user conduct, e-commerce, and
intellectual property. Web site policies--and the overarching concept of web
site governance--are cross-cutting concerns that have to be addressed and
implemented at different levels (e.g., policy documents, legal statements,
business processes, contracts, auditing, and software systems). For web sites,
policies are also reflected in the legal statements that the web site posts,
and in the behavior and features that the web site offers to its users. Both
policies and software tend to evolve independently, but at the same time they
both have to be kept in sync. This is a practical challenge for operators of
web sites that is poorly addressed right now and is, we believe, a promising
avenue for future research. In this paper, we discuss various challenges that
policy poses for web sites with an emphasis on privacy and data protection and
identify open issues for future research.


title: A random matrix theory of decoherence

abstract:
  Random matrix theory is used to represent generic loss of coherence of a
fixed central system coupled to a quantum-chaotic environment, represented by a
random matrix ensemble, via random interactions. We study the average density
matrix arising from the ensemble induced, in contrast to previous studies where
the average values of purity, concurrence, and entropy were considered; we
further discuss when one or the other approach is relevant. The two approaches
agree in the limit of large environments. Analytic results for the average
density matrix and its purity are presented in linear response approximation.
The two-qubit system is analysed, mainly numerically, in more detail.


title: High Energy Neutrinos and Photons from Curvature Pions in Magnetars

abstract:
  We discuss the relevance of the curvature radiation of pions in strongly
magnetized pulsars or magnetars, and their implications for the production of
TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as
high energy photons.


title: Negative Group Velocity: Is It a Backward wave or Fast Light?

abstract:
  When a negative slope of the dispersion curve is encountered, the propagating
light may be either 'fast light' or 'backward propagating'. We show that
causality considerations select only one of which for each scenario, and
demonstrate that the same photonic (plasmonic) system can support both type of
solutions depending on parameters.


title: The cubic fourth-order Schrodinger equation

abstract:
  We investigate the cubic defocusing fourth order Schr\"odinger equation $iu_t
+ \Delta^2u + |u|^2u=0$ in arbitrary space dimension $\mathbb{R}^n$ for
arbitrary $H^2$ initial data. We prove that the equation is globally well-posed
when $n \le 8$ and ill-posed when $n \ge 9$, with the additional important
information that scattering holds true when $5 \le n \le 8$.


title:
Radiative corrections to the three-body region of the Dalitz plot of
  baryon semileptonic decays with angular correlation between polarized emitted
  baryons and charged leptons

abstract:
  We have calculated the radiative corrections to the Dalitz plot of baryon
semileptonic decays with angular correlation between polarized emitted baryons
and charged leptons. This work covers both charged and neutral decaying baryons
and is restricted to the so-called three-body region of the Dalitz plot. Also
it is specialized at the center-of-mass frame of the emitted baryon. We have
considered terms up to order (alpha/pi)(q/M_1)^0, where q is the
momentum-transfer and M_1 is the mass of the decaying baryon, and neglected
terms of order (alpha/pi)(q/M_1)^n$ for n >= 1. The expressions displayed are
ready to obtain numerical results, suitable for model-independent experimental
analyses.


title: Search for CP Violation in B0s to J/psi phi at CDF

abstract:
  The CKM mechanism is well established as the dominant mechanism for $CP$
violation, which was first discovered in the neutral kaons in 1964
\cite{ref:cpkaon}. To search for new sources of CP violation, one can exploit a
handful of systems in which the standard model makes a precise prediction of CP
violation. In the $B^0_s\to J/\psi \phi$ system, CP violation in the
interference of mixing and decay is precisely predicted in the standard model,
the prediction being very close to zero. The CDF experiment reconstructs about
2000 signal events in 1.35 fb$^{-1}$ of luminosity. We obtain a confidence
region in the space of the parameters $\beta_s$, the CP phase, and
$\Delta\Gamma$, the width difference. This result is 1.5 $\sigma$ from the
standard model prediction.


title: Precision study of ground state capture in the 14N(p,gamma)15O reaction

abstract:
  The rate of the hydrogen-burning carbon-nitrogen-oxygen (CNO) cycle is
controlled by the slowest process, 14N(p,gamma)15O, which proceeds by capture
to the ground and several excited states in 15O. Previous extrapolations for
the ground state contribution disagreed by a factor 2, corresponding to 15%
uncertainty in the total astrophysical S-factor. At the Laboratory for
Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep
underground in the Gran Sasso facility in Italy, a new experiment on ground
state capture has been carried out at 317.8, 334.4, and 353.3 keV
center-of-mass energy. Systematic corrections have been reduced considerably
with respect to previous studies by using a Clover detector and by adopting a
relative analysis. The previous discrepancy has been resolved, and ground state
capture no longer dominates the uncertainty of the total S-factor.


title:
Photon storage with sub-nanosecond readout rise time in coupled quantum
  wells

abstract:
  Photon storage with 250 ps rise time of the readout optical signal was
implemented with indirect excitons in coupled quantum well nanostructures
(CQW). The storage and release of photons was controlled by the gate voltage
pulse. The transient processes in the CQW were studied by measuring the
kinetics of the exciton emission spectra after application of the gate voltage
pulse. Strong oscillations of the exciton emission wavelength were observed in
the transient regime when the gate voltage pulse was carried over an ordinary
wire. Gating the CQW via an impedance-matched broadband transmission line has
lead to an effective elimination of these transient oscillations and expedient
switching of the exciton energy to a required value within a short time, much
shorter than the exciton lifetime.


title: SUSY GUT Model Building

abstract:
  I discuss an evolution of SUSY GUT model building, starting with the
construction of 4d GUTs, to orbifold GUTs and finally to orbifold GUTs within
the heterotic string. This evolution is an attempt to obtain realistic string
models, perhaps relevant for the LHC. This review is in memory of the sudden
loss of Julius Wess, a leader in the field, who will be sorely missed.


title: Light Higgs boson scenario in the SUSY seesaw model

abstract:
  It is demonstrated that the light Higgs boson scenario, which the lightest
Higgs mass is less than the LEP bound, mh > 114.4 GeV, is consistent with the
SUSY seesaw model. With the assumptions of the universal right-handed neutrino
mass and the hierarchical mass spectrum of the ordinary neutrinos, the bounds
for the right-handed neutrino mass is investigated in terms of lepton flavor
violating charged lepton decays. We also discuss the effect of the modification
of renormalization group equations by the right-handed neutrinos on the b to s
gamma process and the relic abundance of dark matter in the light Higgs boson
scenario.


title: B-L assisted Anomaly Mediation and the radiative B-L symmetry breaking

abstract:
  Anomaly mediated supersymmetry breaking implemented in the minimal
supersymmetric standard model (MSSM) is known to suffer from the tachyonic
slepton problem leading to breakdown of electric charge conservation. We show
however that when MSSM is extended to explain small neutrino masses by gauging
the B-L symmetry, the slepton masses can be positive due to the Z' mediation
contributions. We obtain various soft supersymmetry breaking mass spectra,
which are different from those obtained in the conventional anomaly mediation
scenario. Then there would be a distinct signature of this scenario at the LHC.


title: Fractional M2-branes

abstract:
  We consider two generalizations of the N=6 superconformal Chern-Simons-matter
theories with gauge group U(N)xU(N). The first generalization is to N=6
superconformal U(M)xU(N) theories, and the second to N=5 superconformal
O(2M)xUSp(2N) and O(2M+1)xUSp(2N) theories. These theories are conjectured to
describe M2-branes probing C^4/Z_k in the unitary case, and C^4/\hat{D}_k in
the orthogonal/symplectic case, together with a discrete flux, which can be
interpreted as |M-N| fractional M2-branes localized at the orbifold
singularity. The classical theories with these gauge groups have been
constructed before; in this paper we focus on some quantum aspects of these
theories, and on a detailed description of their M theory and type IIA string
theory duals.


title:
Local nuclear energy density functional at
  next-to-next-to-next-to-leading order

abstract:
  We construct nuclear energy density functionals in terms of derivatives of
densities up to sixth, next-to-next-to-next-to-leading order (N3LO). A
phenomenological functional built in this way conforms to the ideas of the
density matrix expansion and is rooted in the expansions characteristic to
effective theories. It builds on the standard functionals related to the
contact and Skyrme forces, which constitute the zero-order (LO) and
second-order (NLO) expansions, respectively. At N3LO, the full functional with
density-independent coupling constants, and with the isospin degree of freedom
taken into account, contains 376 terms, while the functionals restricted by the
Galilean and gauge symmetries contain 100 and 42 terms, respectively. For
functionals additionally restricted by the spherical, space-inversion, and
time-reversal symmetries, the corresponding numbers of terms are equal to 100,
60, and 22, respectively.


title: Grain Boundary Motion Exhibits the Dynamics of Glass-Forming Liquids

abstract:
  Polycrystalline materials can be viewed as composites of crystalline
particles or grains separated from one another by thin amorphous grain boundary
(GB) regions. While GB have been exhaustively investigated at low temperatures,
where these regions resolve into complex ordered structures accessible to
measurement, much less is known about them at higher temperatures where the GB
can exhibit significant mobility, structural disorder, and where experimental
characterization methods are limited. The time and spatial scales accessible to
molecular dynamics (MD) simulation make this method appropriate for
investigating both the dynamical and structural properties of grain boundaries
at elevated temperatures. In the present study, we use MD simulations to
determine how the GB dynamics changes with temperature and applied stress. It
has long been hypothesized that GB have features in common with glass-forming
liquids based on the processing characteristics of polycrystalline materials.
We find remarkable support for this suggestion, as evidenced by string-like
collective motion, transient caging of atom motion, and non-Arrhenius
(Vogel-Fulcher) temperature dependence of GB mobility. Evidently, the
frustration caused by the inability of atoms in GB region to simultaneously
order with respect to competing grains is responsible for this striking
similarity. The paradigm that grains in a polycrystalline material are
encapsulated by a frustrated fluid provides a powerful conceptual model of
polycrystalline materials, pointing the way to improved control over their
material properties.


title:
The Burnside Ring-Valued Morse Formula for Vector Fields on Manifolds
  with Boundary

abstract:
  Let G be a compact Lie group and A(G) its Burnside Ring. For a compact smooth
n-dimensional G-manifold X equipped with a generic G-invariant vector field v,
we prove an equivariant analog of the Morse formula
  Ind^G(v) = \sum_{k = 0}^{n} (-1)^k \chi^G(\d_k^+X) which takes its values in
A(G). Here Ind^G(v) denotes the equivariant index of the field v, {\d_k^+X\}
the v-induced Morse stratification (see [M]) of the boundary \d X, and
\chi^G(\d_k^+X) the class of the (n - k)-manifold \d_k^+X in $A(G)$. We examine
some applications of this formula to the equivariant real algebraic fields v in
compact domains X \subset \R^n defined via a generic polynomial inequality.
Next, we link the above formula with the equivariant degrees of certain Gauss
maps. This link is an equivariant generalization of Gottlieb's formulas.


title: Protostar Formation in the Early Universe

abstract:
  The nature of the first generation of stars in the Universe remains largely
unknown. Observations imply the existence of massive primordial stars early in
the history of the universe, and the standard theory for the growth of cosmic
structure predicts that structures grow hierarchically through gravitational
instability. We have developed an ab initio computer simulation of the
formation of primordial stars that follows the relevant atomic and molecular
processes in a primordial gas in an expanding universe. The results show that
primeval density fluctuations left over from the Big Bang can drive the
formation of a tiny protostar with a mass of just one percent that of the Sun.
The protostar is a seed for the subsequent formation of a massive primordial
star.


title: Measuring accurate transit parameters

abstract:
  By observing the transits of exoplanets, one may determine many fundamental
system parameters. I review current techniques and results for the parameters
that can be measured with the greatest precision, specifically, the transit
times, the planetary mass and radius, and the projected spin-orbit angle.


title: Phenomenology of Hybrid Scenarios of Neutrino Dark Energy

abstract:
  We study the phenomenology of hybrid scenarios of neutrino dark energy, where
in addition to a so-called Mass Varying Neutrino (MaVaN) sector a cosmological
constant (from a false vacuum) is driving the accelerated expansion of the
universe today. For general power law potentials we calculate the effective
equation of state parameter w_{eff}(z) in terms of the neutrino mass scale. Due
to the interaction of the dark energy field (acceleron) with the neutrino
sector, w_{eff}(z) is predicted to become smaller than -1 for z>0, which could
be tested in future cosmological observations. For the considered scenarios,
the neutrino mass scale additionally determines which fraction of the dark
energy is dynamical, and which originates from the cosmological constant like
vacuum energy of the false vacuum. On the other hand, the field value of the
acceleron field today as well as the masses of the right-handed neutrinos,
which appear in the seesaw-type mechanism for small neutrino masses, are not
fixed. This, in principle, allows to realise hybrid scenarios of neutrino dark
energy with a high-scale seesaw where the right-handed neutrino masses are
close to the GUT scale. We also comment on how MaVaN Hybrid Scenarios with
high-scale seesaw might help to resolve stability problems of dark energy
models with non-relativistic neutrinos.


title:
Peak energy of the prompt emission of long Gamma Ray Bursts vs their
  fluence and peak flux

abstract:
  The spectral-energy and (luminosity) correlations in long GRBs are being
hotly debated to establish, first of all, their reality against possible
selection effects. These are best studied in the observer planes, namely the
peak energy E_peak_obs vs the fluence F or the peak flux P. In a recent paper
we started to attack this problem considering all GRBs with known z and
spectral properties. Here we consider instead all bursts with known E_peak_obs,
irrespective of z, adding to those a sample of 100 faint BATSE bursts
representative of a larger population. This allows us to construct a complete,
fluence limited, sample, to study the selection/instrumental effects. We found
that fainter bursts have smaller E_peak_obs than those of bright events. As a
consequence, the E_peak_obs of these bursts is correlated with the fluence,
though with a slope flatter than that defined by bursts with z. Selection
effects, which are present, are shown not to be responsible for the existence
of such a correlation. About 6% of these bursts are surely outliers of the
E_peak-E_iso correlation (updated to include 83 bursts), since they are
inconsistent with it for any z. E_peak_obs correlates also with P, with a slope
similar to the E_peak-L_iso correlation.In this case there is only one sure
outlier.The scatter of the E_peak_obs-P correlation defined by the BATSE bursts
of our sample is smaller than the E_peak_obs-F correlation of the same bursts,
while for the bursts with known z the E_peak-E_iso correlation is tighter than
the E_peak-L_iso one. Once a very large number of bursts with E_peak_obs and z
will be available, we thus expect that the E_peak-L_iso correlation will be
similar to that currently found, whereas it is likely that the E_peak-E_iso
correlation will become flatter and with a larger scatter.


title:
Galaxy Clustering & Galaxy-Galaxy Lensing: A Promising Union to
  Constrain Cosmological Parameters

abstract:
  Galaxy clustering and galaxy-galaxy lensing probe the connection between
galaxies and their dark matter haloes in complementary ways. On one hand, the
halo occupation statistics inferred from the observed clustering properties of
galaxies are degenerate with the adopted cosmology. Consequently, different
cosmologies imply different mass-to-light ratios for dark matter haloes. On the
other hand, galaxy-galaxy lensing yields direct constraints on the actual
mass-to-light ratios and it can be used to break this degeneracy, and thus to
constrain cosmological parameters. In this paper we establish the link between
galaxy luminosity and dark matter halo mass using the conditional luminosity
function (CLF). We constrain the CLF parameters using the galaxy luminosity
function and the luminosity dependence of the correlation lengths of galaxies.
The resulting CLF models are used to predict the galaxy-galaxy lensing signal.
For a cosmology with $(\Omega_{\rm m},\sigma_8)=(0.238,0.734)$, the model
accurately fits the galaxy-galaxy lensing data obtained from the SDSS. For a
comparison cosmology with $(\Omega_{\rm m},\sigma_8)=(0.3,0.9)$, however, we
can accurately fit the luminosity function and clustering properties of the
galaxy population, but the model predicts mass-to-light ratios that are too
high, resulting in a strong overprediction of the galaxy-galaxy lensing signal.
We conclude that the combination of galaxy clustering and galaxy-galaxy lensing
is a powerful probe of the galaxy-dark matter connection, with the potential to
yield tight constraints on cosmological parameters. Since this method mainly
probes the mass distribution on non-linear scales, it is complementary to
constraints obtained from the galaxy power-spectrum, which mainly probes the
large-scale (linear) matter distribution.


title:
Using Ultra Long Period Cepheids to Extend the Cosmic Distance Ladder to
  100 Mpc and Beyond

abstract:
  We examine the properties of 17 long period (80-180 days) and very luminous
(median absolute magnitude of M_I= -7.93 and M_V= -7.03) Cepheids to see if
they can serve as an useful distance indicator. We find that these Ultra Long
Period (ULP) Cepheids have a relatively shallow Period-Luminosity (PL)
relation, so in fact they are more "standard candle"-like than classical
Cepheids. In the reddening-free Wesenheit index, the slope of the ULP PL
relation is ~10 times less steep than the standard PL relation for the SMC
Cepheids. The scatter of our sample about the W_I PL relation is 0.22 mag,
approaching that of classical Cepheids and Type Ia Supernovae. We expect this
scatter to decrease as bigger and more uniform samples of ULP Cepheids are
obtained. We also measure a non-zero period derivative for one ULP Cepheid (SMC
HV829) and use the result to probe evolutionary models and mass loss of massive
stars. ULP Cepheids main advantage over classical Cepheids is that they are
more luminous, and as such show great potential as stellar distance indicators
to galaxies up to 100 Mpc and beyond.


title: Modeling Galaxy-Galaxy Weak Lensing with SDSS Groups

abstract:
  We use galaxy groups selected from the Sloan Digital Sky Survey (SDSS)
together with mass models for individual groups to study the galaxy-galaxy
lensing signals expected from galaxies of different luminosities and
morphological types. We compare our model predictions with the observational
results obtained from the SDSS by Mandelbaum et al. (2006) for the same samples
of galaxies. The observational results are well reproduced in a $\Lambda$CDM
model based on the WMAP 3-year data, but a $\Lambda$CDM model with higher
$\sigma_8$, such as the one based on the WMAP 1-year data,significantly
over-predicts the galaxy-galaxy lensing signal. We model, separately, the
contributions to the galaxy-galaxy lensing signals from different galaxies:
central versus satellite, early-type versus late-type, and galaxies in halos of
different masses. We also examine how the predicted galaxy-galaxy lensing
signal depends on the shape, density profile, and the location of the central
galaxy with respect to its host halo.