title:
Flexible multivariate marginal models for analyzing multivariate
  longitudinal data, with applications in R

abstract:
  Most of the available multivariate statistical models dictate on fitting
different parameters for the covariate effects on each multiple responses. This
might be unnecessary and inefficient for some cases. In this article, we
propose a modeling framework for multivariate marginal models to analyze
multivariate longitudinal data which provides flexible model building
strategies. We show that the model handles several response families such as
binomial, count and continuous. We illustrate the model on the Mother's Stress
and Children's Morbidity data set. A simulation study is conducted to examine
the parameter estimates. An R package mmm2 is proposed to fit the model.


title: The Operator Algebra content of the Ramanujan-Petersson Problem

abstract:
  Let $G$ be a discrete countable group, and let $\Gamma$ be an almost normal
subgroup. In this paper we investigate the classification of (projective)
unitary representations $\pi$ of $G$ into the unitary group of the Hilbert
space $l^2(\Gamma)$ that extend the left regular representation of $\Gamma$.
Representations with this property are obtained by restricting to $G$ square
integrable representations of a larger semisimple Lie group $\bar G$,
containing $G$ as dense subgroup and such that $\Gamma$ is a lattice in $\bar
G$. This type of unitary representations of of $G$ appear in the study of
automorphic forms.
  We prove that the Ramanujan-Petersson problem regarding the action of the
Hecke algebra on the Hilbert space of $\Gamma$-invariant vectors for the
unitary representation $\pi\otimes \bar\pi$ is an intrinsic problem on the
outer automorphism group of the von Neumann algebra $\mathcal L(G \rtimes
L^{\infty}(\mathcal G,\mu))$, where $\mathcal G$ is the Schlichting completion
of $G$ and $\mu $ is the canonical Haar measure on $\mathcal G$.


title: The GBC mass for asymptotically hyperbolic manifolds

abstract:
  The paper consists of two parts. In the first part, by using the Gauss-Bonnet
curvature, which is a natural generalization of the scalar curvature, we
introduce a higher order mass, the Gauss-Bonnet-Chern mass $m^{\H}_k$, for
asymptotically hyperbolic manifolds and show that it is a geometric invariant.
Moreover, we prove a positive mass theorem for this new mass for asymptotically
hyperbolic graphs and establish a relationship between the corresponding
Penrose type inequality for this mass and weighted Alexandrov-Fenchel
inequalities in the hyperbolic space $\H^n$. In the second part, we establish
these weighted Alexandrov-Fenchel inequalities in $\H^n$ for any horospherical
convex hypersurface $\Sigma$. As an application, we obtain an optimal Penrose
type inequality for the new mass defined in the first part for asymptotically
hyperbolic graphs with a horizon type boundary $\Sigma$, provided that a
dominant energy condition $\tilde L_k\ge0$ holds. Both inequalities are
optimal.


title: Edge Channel Transport in InAs/GaSb Topological Insulating Phase

abstract:
  Transport in InAs/GaSb heterostructures with different InAs layer thicknesses
is studied using a six-terminal Hall bar geometry with a 2-$\mu$m edge channel
length. For a sample with a 12-nm-thick InAs layer, non-local resistance
measurements with various current/voltage contact configurations reveal that
the transport is dominated by edge channels with negligible bulk contribution.
Systematic non-local measurements allow us to extract the resistance of
individual edge channels, revealing sharp resistance uctuations indicative of
inelastic scattering. Our results show that the InAs/GaSb system can be
tailored to have conducting edge channels while keeping a gap in the bulk
region and provide a way of studying 2D topological insulators even when
quantized transport is absent.


title: Mathematics via Symmetry

abstract:
  We state the defining characteristic of mathematics as a type of symmetry
where one can change the connotation of a mathematical statement in a certain
way when the statement's truth value remains the same. This view of mathematics
as satisfying such symmetry places mathematics as comparable with modern views
of physics and science where, over the past century, symmetry also plays a
defining role. We explore the very nature of mathematics and its relationship
with natural science from this perspective. This point of view helps clarify
some standard problems in the philosophy of mathematics.


title: Hypergraphs of bounded disjointness

abstract:
  A $k$-uniform hypergraph is $s$-almost intersecting if every edge is disjoint
from exactly $s$ other edges. Gerbner, Lemons, Palmer, Patk\'os and Sz\'ecsi
conjectured that for every $k$, and $s>s_0(k)$, every $k$-uniform $s$-almost
intersecting hypergraph has at most $(s+1)\binom{2k-2}{k-1}$ edges. We prove a
strengthened version of this conjecture and determine the extremal graphs. We
also give some related results and conjectures.


title:
Non-existence of an invariant measure for a homogeneous ellipsoid
  rolling on the plane

abstract:
  It is known that the reduced equations for an axially symmetric homogeneous
ellipsoid that rolls without slipping on the plane possess a smooth invariant
measure. We show that such an invariant measure does not exist in the case when
all of the semi-axes of the ellipsoid have different length.


title:
Fluctuations in the electron system of a superconductor exposed to a
  photon flux

abstract:
  We report on fluctuations in the electron system, Cooper pairs and
quasiparticles, of a superconducting aluminium film. The superconductor is
exposed to pair-breaking photons (1.54 THz), which are coupled through an
antenna. The change in the complex conductivity of the superconductor upon a
change in the quasiparticle number is read out by a microwave resonator. A
large range in radiation power can be chosen by carefully filtering the
radiation from a blackbody source. We identify two regimes. At high radiation
power, fluctuations in the electron system caused by the random arrival rate of
the photons are resolved, giving a straightforward measure of the optical
efficiency (48%). At low radiation power fluctuations are dominated by excess
quasiparticles, the number of which is measured through their recombination
lifetime.


title: The construction of finite solvable groups revisited

abstract:
  We describe a new approach towards the systematic construction of finite
groups up to isomorphism. This approach yields a practical algorithm for the
construction of finite solvable groups up to isomorphism. We report on a GAP
implementation of this method for finite solvable groups and exhibit some
sample applications.


title: Flexoelectricity from density-functional perturbation theory

abstract:
  We derive the complete flexoelectric tensor, including electronic and
lattice-mediated effects, of an arbitrary insulator in terms of the microscopic
linear response of the crystal to atomic displacements. The basic ingredient,
which can be readily calculated from first principles in the framework of
density-functional perturbation theory, is the quantum-mechanical probability
current response to a long-wavelength acoustic phonon. Its second-order Taylor
expansion in the wavevector q around the Gamma (q=0) point in the Brillouin
zone naturally yields the flexoelectric tensor. At order one in q we recover
Martin's theory of piezoelectricity [R. M. Martin, Phys. Rev. B 5, 1607
(1972)], thus providing an alternative derivation thereof. To put our
derivations on firm theoretical grounds, we perform a thorough analysis of the
nonanalytic behavior of the dynamical matrix and other response functions in a
vicinity of Gamma. Based on this analysis, we find that there is an ambiguity
in the specification of the "zero macroscopic field" condition in the
flexoelectric case; such arbitrariness can be related to an analytic
band-structure term, in close analogy to the theory of deformation potentials.
As a byproduct, we derive a rigorous generalization of the Cochran-Cowley
formula [W. Cochran and R. A. Cowley, J. Phys. Chem. Solids 23, 447 (1962)] to
higher orders in q. This can be of great utility in building reliable atomistic
models of electromechanical phenomena, as well as for improving the accuracy of
the calculation of phonon dispersion curves. Finally, we discuss the physical
interpretation of the various contributions to the flexoelectric response,
either in the static or dynamic regime.


title: The hyperholomorphic line bundle

abstract:
  We study the hyperholomorphic line bundle on a hyperkaehler manifold with
circle action introduced by A Haydys, and in particular show how it transforms
under a hyperkaehler quotient. Applications include ALE spaces and coadjoint
orbits.


title: Certified Impossibility Results for Byzantine-Tolerant Mobile Robots

abstract:
  We propose a framework to build formal developments for robot networks using
the COQ proof assistant, to state and to prove formally various properties. We
focus in this paper on impossibility proofs, as it is natural to take advantage
of the COQ higher order calculus to reason about algorithms as abstract
objects. We present in particular formal proofs of two impossibility results
forconvergence of oblivious mobile robots if respectively more than one half
and more than one third of the robots exhibit Byzantine failures, starting from
the original theorems by Bouzid et al.. Thanks to our formalization, the
corresponding COQ developments are quite compact. To our knowledge, these are
the first certified (in the sense of formally proved) impossibility results for
robot networks.


title: Polygonal billiards with one side scattering

abstract:
  We study polygonal billiards with one-sided vertical mirror scattered on a
square billiard table. We associate trajectories of these kinds of billiards
with double rotations and study orbit behavior and questions of complexity.


title:
A quasi-polynomial algorithm for discrete logarithm in finite fields of
  small characteristic

abstract:
  In the present work, we present a new discrete logarithm algorithm, in the
same vein as in recent works by Joux, using an asymptotically more efficient
descent approach. The main result gives a quasi-polynomial heuristic complexity
for the discrete logarithm problem in finite field of small characteristic. By
quasi-polynomial, we mean a complexity of type $n^{O(\log n)}$ where $n$ is the
bit-size of the cardinality of the finite field. Such a complexity is smaller
than any $L(\varepsilon)$ for $\epsilon>0$. It remains super-polynomial in the
size of the input, but offers a major asymptotic improvement compared to
$L(1/4+o(1))$.


title:
Pair versus Solo Programming -- An Experience Report from a Course on
  Design of Experiments in Software Engineering

abstract:
  This paper presents an experience report about an experiment that evaluates
duration and effort of pair and solo programming. The experiment was performed
as part of a course on Design of Experiments (DOE) in Software Engineering (SE)
at Autonomous University of Yucatan (UADY). A total of 21 junior student
subjects enrolled in the bachelor's degree program in SE participated in the
experiment. During the experiment, subjects (7 pairs and 7 solos) wrote two
small programs in two sessions. Results show a significant difference (at
alpha=0.1) in favor of pair programming regarding duration (28% decrease), and
a significant difference (at alpha=0.1) in favor of solo programming with
respect to effort (30% decrease). With only a difference of 1%, our results
regarding duration and effort are practically the same as those reported by
Nosek in 1998.


title: Growth rates of geometric grid classes of permutations

abstract:
  Geometric grid classes of permutations have proven to be key in
investigations of classical permutation pattern classes. By considering the
representation of gridded permutations as words in a trace monoid, we prove
that every geometric grid class has a growth rate which is given by the square
of the largest root of the matching polynomial of a related graph. As a
consequence, we characterise the set of growth rates of geometric grid classes
in terms of the spectral radii of trees, explore the influence of "cycle
parity" on the growth rate, compare the growth rates of geometric grid classes
against those of the corresponding monotone grid classes, and present new
results concerning the effect of edge subdivision on the largest root of the
matching polynomial.


title:
Controlled energy-selected electron capture and release in double
  quantum dots

abstract:
  Highly accurate quantum electron dynamics calculations demonstrate that
energy can be efficiently transferred between quantum dots. Specifically, in a
double quantum dot an incoming electron is captured by one dot and the excess
energy is transferred to the neighboring dot and used to remove an electron
from this dot. This process is due to long-range electron correlation and shown
to be operative at rather large distances between the dots. The efficiency of
the process is greatly enhanced by preparing the double quantum dot such that
the incoming electron is initially captured by a two-electron resonance state
of the system. In contrast to atoms and molecules in nature, double quantum
dots can be manipulated to achieve this enhancement. This mechanism leads to a
surprisingly narrow distribution of the energy of the electron removed in the
process which is explained by resonance theory. We argue that the process could
be exploited in practice.


title: Conformal Trace Relations from the Dilaton Wess-Zumino Action

abstract:
  We use the method of Weyl-gauging in the determination of the Wess-Zumino
conformal anomaly action, to show that in any even ($d = 2 k$) dimensions all
the hierarchy of correlation functions involving traces of the energy-momentum
tensor is determined in terms of those of lower orders, up to $2 k$. We work
out explicitly the case $d=4$, and show that in this case in any conformal
field theory only the first 4 traced correlators are independent. All the
remaining correlators are recursively generated by the first 4. The result is a
consequence of the cocycle condition which defines the Wess-Zumino action and
of the finite order of its dilaton interactions.


title:
Parabolic Equation with Nonlocal Diffusion without a Smooth Inertial
  Manifold

abstract:
  We construct an example of a one-dimensional parabolic integro-differential
equation with nonlocal diffusion which does not have asymptotically
finite-dimensional dynamics in the corresponding state space. This example is
more natural in the class of evolutionary equations of parabolic type than
those known earlier.


title: On a type of semi-sub-Riemannian connection on a sub-Riemannian manifold

abstract:
  The authors first in this paper define a semi-symmetric metric non-holonomic
connection (called in briefly a semi-sub-Riemannian connection) on
sub-Riemannian manifolds, and study the relations between sub-Riemannian
connections and semi-sub-Riemannian connections. An invariant under a
connection transformation $\nabla\rightarrow D$ is obtained. The authors then
further deduce a sufficient and necessary condition that a sub-Riemannian
manifold associated with a semi-sub-Riemannian connection is flat, and derive
that a sub-Riemannian manifold with vanishing curvature with respect to
semi-sub-Riemannnian connection $D$ is a group manifold if and only if it is of
constant curvature.


title: Quantum bicriticality in the heavy-fermion metamagnet YbAgGe

abstract:
  Bicritical points, at which two distinct symmetry-broken phases become
simultaneously unstable, are typical for spin-flop metamagnetism.
Interestingly, the heavy-fermion compound YbAgGe also possesses such a
bicritical point (BCP) with a low temperature T_BCP ~ 0.3 K at a magnetic field
of mu_0 H_BCP ~ 4.5 T. In its vicinity, YbAgGe exhibits anomalous behavior that
we attribute to the influence of a quantum bicritical point (QBCP), that is
close in parameter space yet can be reached by tuning T_BCP further to zero.
Using high-resolution measurements of the magnetocaloric effect, we demonstrate
that the magnetic Grueneisen parameter Gamma_H indeed both changes sign and
diverges as required for quantum criticality. Moreover, Gamma_H displays a
characteristic scaling behavior but only on the low-field side, H < H_BCP,
indicating a pronounced asymmetry with respect to the critical field. We
speculate that the small value of T_BCP is related to the geometric frustration
of the Kondo-lattice of YbAgGe.


title: A quantum particle in a box with moving walls

abstract:
  We analyze the non-relativistic problem of a quantum particle that bounces
back and forth between two moving walls. We recast this problem into the
equivalent one of a quantum particle in a fixed box whose dynamics is governed
by an appropriate time-dependent Schroedinger operator.


title:
Systematic assessment of the expected length, variance and distribution
  of Longest Common Subsequences

abstract:
  The Longest Common Subsequence (LCS) problem is a very important problem in
math- ematics, which has a broad application in scheduling problems, physics
and bioinformatics. It is known that the given two random sequences of infinite
lengths, the expected length of LCS will be a constant. however, the value of
this constant is not yet known. Moreover, the variance distribution of LCS
length is also not fully understood. The problem becomes more difficult when
there are (a) multiple sequences, (b) sequences with non-even distribution of
alphabets and (c) large alphabets. This work focus on these more complicated
issues. We have systematically analyze the expected length, variance and
distribution of LCS based on extensive Monte Carlo simulation. The results on
expected length are consistent with currently proved theoretical results, and
the analysis on variance and distribution provide further insights into the
problem.


title:
Ground-state degeneracy for abelian anyons in the presence of gapped
  boundaries

abstract:
  Gapped phases with long-range entanglement may admit gapped boundaries. If
the boundary is gapped, the ground-state degeneracy is well-defined and can be
computed using methods of Topological Quantum Field Theory. We derive a general
formula for the ground-state degeneracy for abelian Fractional Quantum Hall
phases, including the cases when connected components of the boundary are
subdivided into an arbitrary number of segments, with a different boundary
condition on each segment, and in the presence of an arbitrary number of
boundary domain walls.


title: Spinor dynamics in an antiferromagnetic spin-1 thermal Bose gas

abstract:
  We present experimental observations of coherent spin-population oscillations
in a cold thermal, Bose gas of spin-1 sodium-23 atoms. The population
oscillations in a multi-spatial-mode thermal gas have the same behavior as
those observed in a single-spatial-mode antiferromagnetic spinor Bose Einstein
condensate. We demonstrate this by showing that the two situations are
described by the same dynamical equations, with a factor of two change in the
spin-dependent interaction coefficient, which results from the change to
particles with distinguishable momentum states in the thermal gas. We compare
this theory to the measured spin population evolution after times up to a few
hundreds of ms, finding quantitative agreement with the amplitude and period.
We also measure the damping time of the oscillations as a function of magnetic
field.


title:
The multivariate Krawtchouk polynomials as matrix elements of the
  rotation group representations on oscillator states

abstract:
  An algebraic interpretation of the bivariate Krawtchouk polynomials is
provided in the framework of the 3-dimensional isotropic harmonic oscillator
model. These polynomials in two discrete variables are shown to arise as matrix
elements of unitary reducible representations of the rotation group in 3
dimensions. Many of their properties are derived by exploiting the
group-theoretic setting. The bivariate Tratnik polynomials of Krawtchouk type
are seen to be special cases of the general polynomials that correspond to
particular rotations involving only two parameters. It is explained how the
approach generalizes naturally to (d+1) dimensions and allows to interpret
multivariate Krawtchouk polynomials as matrix elements of SO(d+1) unitary
representations. Indications are given on the connection with other algebraic
models for these polynomials.


title:
Effect of spin-orbit interaction on the excitonic effects in
  single-layer, double-layer, and bulk MoS2

abstract:
  We present converged ab-initio calculations of the optical absorption spectra
of single-layer, bi-layer, and bulk MoS$_2$. Both the quasiparticle-energy
calculations (on the level of the GW approximation) and the calculation of the
absorption spectra (on the level of the Bethe-Salpeter equation) explicitly
include spin-orbit coupling, using the full spinorial Kohn-Sham wave-functions
as input. Without excitonic effects, the absorption spectra would have the form
of a step-function, corresponding to the joint-density of states of a parabolic
band-dispersion in 2D. This profile is deformed by a pronounced bound excitonic
peak below the continuum onset. The peak is split by spin-orbit interaction in
the case of single-layer and (mostly) by inter-layer interaction in the case of
double-layer and bulk MoS$_2$. The resulting absorption spectra are thus very
similar in the three cases but the interpretation of the spectra is different.
Differences in the spectra can be seen around 3 eV where the spectra of single
and double-layer are dominated by a strongly bound exciton.


title:
Matter mixing in aspherical core-collapse supernovae: a search for
  possible conditions for conveying $^{56}$Ni into high velocity regions

abstract:
  We perform two-dimensional axisymmetric hydrodynamic simulations of matter
mixing in aspherical core-collapse supernova explosions of a 16.3 $M_{\odot}$
star with a compact hydrogen envelope. Observations of SN 1987A have provided
evidence that $^{56}$Ni synthesized by explosive nucleosynthesis is mixed into
fast moving matter ($\gtrsim$ 3,500 km s$^{-1}$) in the exploding star. In
order to clarify the key conditions for reproducing such high velocity of
$^{56}$Ni, we revisit matter mixing in aspherical core-collapse supernova
explosions. Explosions are initiated artificially by injecting thermal and
kinetic energies around the interface between the iron core and the
silicon-rich layer. Perturbations of 5% or 30% amplitude in the radial
velocities are introduced at several points in time. We found that no high
velocity $^{56}$Ni can be obtained if we consider bipolar explosions with
perturbations (5% amplitude) of pre-supernova origins. If large perturbations
(30% amplitude) are introduced or exist due to some unknown mechanism in a
later phase just before the shock wave reaches the hydrogen envelope, $^{56}$Ni
with a velocity of 3,000 km s$^{-1}$ can be obtained. Aspherical explosions
that are asymmetric across the equatorial plane with clumpy structures in the
initial shock waves are investigated. We found that the clump sizes affect the
penetration of $^{56}$Ni. Finally, we report that an aspherical explosion model
that is asymmetric across the equatorial plane with multiple perturbations of
pre-supernova origins can cause the penetration of $^{56}$Ni clumps into fast
moving matter of 3,000 km s$^{-1}$. We show that both aspherical explosion with
clumpy structures and perturbations of pre-supernova origins may be necessary
to reproduce the observed high velocity of $^{56}$Ni. To confirm this, more
robust three-dimensional simulations are required.


title:
Direct Numerical Simulation of Electrokinetic Instability and Transition
  to Chaotic Motion

abstract:
  A new type of instability - electrokinetic instability - and an unusual
transition to chaotic motion near a charge-selective surface was studied by
numerical integration of the Nernst-Planck-Poisson-Stokes system and a weakly
nonlinear analysis near the threshold of instability. Two kinds of initial
conditions were considered: (a) white noise initial conditions to mimic "room
disturbances" and subsequent natural evolution of the solution; (b) an
artificial monochromatic ion distribution with a fixed wave number to simulate
regular wave patterns. The results were studied from the viewpoint of
hydrodynamic stability and bifurcation theory. The threshold of
electroconvective movement was found by the linear spectral stability theory,
the results of which were confirmed by numerical simulation of the entire
system. The following regimes, which replace each other as the potential drop
between the selective surfaces increases, were obtained: one-dimensional steady
solution; two-dimensional steady electroconvective vortices (stationary point
in a proper phase space); unsteady vortices aperiodically changing their
parameters (homoclinic contour); periodic motion (limit cycle); and chaotic
motion. The transition to chaotic motion did not include Hopf bifurcation.
Numerical resolution of the thin concentration polarization layer showed
spike-like charge profiles along the surface, which could be, depending on the
regime, either steady or aperiodically coalescent.
  The numerical investigation confirmed the experimentally observed absence of
regular (near-sinusoidal) oscillations for the overlimiting regimes. There is a
qualitative agreement of the experimental and the theoretical values of the
threshold of instability, the dominant size of the observed coherent
structures, and the experimental and theoretical volt-current characteristics.


title: Regularity at the free boundary for Dirac-harmonic maps from surfaces

abstract:
  We establish the regularity theory for certain critical elliptic systems with
an anti-symmetric structure under inhomogeneous Neumann and Dirichlet boundary
constraints. As applications, we prove full regularity and smooth estimates at
the free boundary for weakly Dirac-harmonic maps from spin Riemann surfaces.
Our methods also lead to the full interior $\epsilon$-regularity and smooth
estimates for weakly Dirac-harmonic maps in all dimensions.


title:
Quantum generalized fluctuation-dissipation relations in terms of
  time-distributed observations

abstract:
  New formulations of quantum generalized fluctuation-dissipation relations in
terms of characteristic and probabilistic functionals of continuous
observations are suggested and discussed. It is shown that control of entropy
production in quantum system turns any measurement in it to a source of its
extra perturbations, and because of this effect relations between probabilities
of mutually time-reversed processes become definitely non-local in their
functional space


title:
Long lifetime and high-fidelity quantum memory of photonic polarization
  qubit by lifting Zeeman degeneracy

abstract:
  Long-lived and high-fidelity memory for photonic polarization qubit (PPQ) is
crucial for constructing quantum networks. Here we present an EIT-based
millisecond storage system in which a moderate magnetic field is applied on a
cold-atom cloud to lift Zeeman degeneracy. PPQ states are stored as two
magnetic-field-insensitive spin waves. Especially, the influence of
magnetic-field-sensitive spin waves on the storage performances is almost
totally avoided. The measured average fidelities of polarization states are
98.6% at 200 us and 78.4% at 4.5 ms, respectively.


title: Ore Polynomials in Sage

abstract:
  We present a Sage implementation of Ore algebras. The main features for the
most common instances include basic arithmetic and actions; gcrd and lclm;
D-finite closure properties; natural transformations between related algebras;
guessing; desingularization; solvers for polynomials, rational functions and
(generalized) power series. This paper is a tutorial on how to use the package.


title:
Planet or Brown Dwarf? Inferring the Companion Mass in HD 100546 from
  the Wall Shape using Mid-Infrared Interferometry

abstract:
  Giant planets form in protoplanetary disks while these disks are still
gas-rich, and can reveal their presence through the annular gaps they carve
out. HD 100546 is a gas-rich disk with a wide gap between between a radius of
~1 and 13 AU, possibly cleared out by a planetary companion or planetary
system. We want to identify the nature of the unseen companion near the far end
of the disk gap. We use mid-infrared interferometry at multiple baselines to
constrain the curvature of the disk wall at the far end of the gap. We use 2D
hydrodynamical simulations of embedded planets and brown dwarfs to estimate
viscosity of the disk and the mass of a companion close to the disk wall. We
find that the disk wall at the far end of the gap is not vertical, but
rounded-off by a gradient in the surface density. Such a gradient can be
reproduced in hydrodynamical simulations with a single, heavy companion
(>=30...80 M_Jup) while the disk has viscosity of at least \alpha{} >~ 5 10^-3.
Taking into account the changes in the temperature structure after gap opening
reduces the lower limit on the planet mass and disk viscosity to 20 M_Jup and
\alpha{} = 2 10^-3. The object in the disk gap of HD 100546 that shapes the
disk wall is most likely a 60(+20)(-40) M_Jup brown dwarf, while the disk
viscosity is estimated to be at least \alpha{} = 2 10^-3. The disk viscosity is
an important factor in estimating planetary masses from disk morphologies: more
viscous disks need heavier planets to open an equally deep gap.


title:
Bounding the Estimation Error of Sampling-based Shapley Value
  Approximation

abstract:
  The Shapley value is arguably the most central normative solution concept in
cooperative game theory. It specifies a unique way in which the reward from
cooperation can be "fairly" divided among players. While it has a wide range of
real world applications, its use is in many cases hampered by the hardness of
its computation. A number of researchers have tackled this problem by (i)
focusing on classes of games where the Shapley value can be computed
efficiently, or (ii) proposing representation formalisms that facilitate such
efficient computation, or (iii) approximating the Shapley value in certain
classes of games. For the classical \textit{characteristic function}
representation, the only attempt to approximate the Shapley value for the
general class of games is due to Castro \textit{et al.} \cite{castro}. While
this algorithm provides a bound on the approximation error, this bound is
\textit{asymptotic}, meaning that it only holds when the number of samples
increases to infinity. On the other hand, when a finite number of samples is
drawn, an unquantifiable error is introduced, meaning that the bound no longer
holds. With this in mind, we provide non-asymptotic bounds on the estimation
error for two cases: where (i) the \textit{variance}, and (ii) the
\textit{range}, of the players' marginal contributions is known. Furthermore,
for the second case, we show that when the range is significantly large
relative to the Shapley value, the bound can be improved (from $O(\frac{r}{m})$
to $O(\sqrt{\frac{r}{m}})$). Finally, we propose, and demonstrate the
effectiveness of using stratified sampling for improving the bounds further.


title: Quantized Superfluid Vortex Rings in the Unitary Fermi Gas

abstract:
  In a recent article, Yefsah et al. [Nature 499, 426 (2013)] report the
observation of an unusual excitation in an elongated harmonically trapped
unitary Fermi gas. After phase imprinting a domain wall, they observe
oscillations almost an order of magnitude slower than predicted by any theory
of domain walls which they interpret as a "heavy soliton" of inertial mass some
200 times larger than the free fermion mass or 50 times larger than expected
for a domain wall. We present compelling evidence that this "soliton" is
instead a quantized vortex ring by showing that the main aspects of the
experiment can be naturally explained within the framework of time-dependent
superfluid DFT.


title: Electronic Raman scattering from orbital nematic fluctuations

abstract:
  We compute Raman scattering intensities via the lowest-order coupling to the
bosonic propagator associated with orbital nematic fluctuations in a minimal
model for iron pnictides. The model consists of two bands on a square lattice
exhibiting four Fermi pockets and a transition from the normal to a nematic
state. It is shown that the orbital fluctuations produce in the B1g channel
strong quasi-elastic light scattering around the nematic critical temperature
Tn, both above and below Tn. This holds for the A1g symmetry only below Tn
whereas no low-energy scattering from orbital fluctuations is found in the B2g
symmetry. Due to the nematic distortion the electron pocket at the X-point may
disappear at low temperatures. Such a Lifshitz transition causes in the B2g
spectrum a large upward shift of spectral weight in the high energy region
whereas no effect is seen in the other symmetries.


title: Complex state induced by impurities in multiband superconductors

abstract:
  We study the role of impurities in a two-band superconductor, and elucidate
the nature of the recently predicted transition from s_{+-} state to s_{++}
state induced by interband impurity scattering. Using a Ginzburg-Landau theory,
derived from microscopic equations, we demonstrate that close to T_c this
transition is necessarily a direct one, but deeper in the superconducting state
an intermediate complex state appears. This state has a distinct order
parameter, which breaks the time-reversal symmetry, and is separated from the
s_{+-} and s_{++} states by phase transitions. Based on our results, we suggest
a phase diagram for systems with weak repulsive interband pairing, and discuss
its relevance to iron-based superconductors.


title:
Gapless spin liquid ground state in the S=1/2 vanadium oxyfluoride
  kagome antiferromagnet [NH4]2[C7H14N][V7O6F18]

abstract:
  The vanadium oxyfluoride [NH4]2[C7H14N][V7O6F18] (DQVOF) is a geometrically
frustrated magnetic bilayer material. The structure consists of S=1/2 kagome
planes of V4+ d1 ions with S=1 V3+ d2 ions located between the kagome layers.
Muon spin relaxation measurements demonstrate the absence of spin freezing down
to 40 mK despite an energy scale of 60 K for antiferromagnetic exchange
interactions. From magnetization and heat capacity measurements we conclude
that the S=1 spins of the interplane V3+ ions are weakly coupled to the kagome
layers, such that DQVOF can be viewed as an experimental model for S=1/2 kagome
physics, and that it displays a gapless spin liquid ground state.


title:
Computational investigations of folded self-avoiding walks related to
  protein folding

abstract:
  Various subsets of self-avoiding walks naturally appear when investigating
existing methods designed to predict the 3D conformation of a protein of
interest. Two such subsets, namely the folded and the unfoldable self-avoiding
walks, are studied computationally in this article. We show that these two sets
are equal and correspond to the whole $n$-step self-avoiding walks for
$n\leqslant 14$, but that they are different for numerous $n \geqslant 108$,
which are common protein lengths. Concrete counterexamples are provided and the
computational methods used to discover them are completely detailed. A tool for
studying these subsets of walks related to both pivot moves and proteins
conformations is finally presented.


title:
Mechanical properties and microdomain separation of fluid membranes with
  anchored polymers

abstract:
  The entropic effects of anchored polymers on biomembranes are studied using
simulations of a meshless membrane model combined with anchored linear polymer
chains. The bending rigidity and spontaneous curvature are investigated for
anchored ideal and excluded-volume polymer chains. Our results are in good
agreement with the previous theoretical predictions. It is found that the
polymer reduces the line tension of membrane edges, as well as the interfacial
line tension between membrane domains, leading to microdomain formation.
Instead of the mixing of two phases as observed in typical binary fluids,
densely anchored polymers stabilize small domains. A mean field theory is
proposed for the edge line tension reduced by anchored ideal chains, which
reproduces our simulation results well.


title:
Spatio-kinematic modelling of Abell 65, a double-shelled planetary
  nebula with a binary central star

abstract:
  We present the first detailed spatio-kinematical analysis and modelling of
the planetary nebula Abell 65, which is known to host a post-common envelope,
binary, central star system. As such, this object is of great interest in
studying the link between nebular morphology and central star binarity.
  [OIII]5007A and H-alpha+[NII]6584A longslit spectra and imagery of Abell 65
were obtained with the Manchester Echelle Spectrometer on the 2.1-m telescope
at the San Pedro Martir Observatory (MES-SPM). Further [OIII]5007A longslit
spectra were obtained with the Ultraviolet and Visual Echelle Spectrograph on
the Very Large Telescope (VLT-UVES). These data were used to develop a
spatio-kinematical model for the [OIII]5007A emission from Abell 65. A
"best-fit" model was found by comparing synthetic spectra and images rendered
from the model to the data. The model comprises an outer shell and an inner
shell, with kinematical ages of 15000 +/- 5000 yr kpc^-1 and 8000 +/- 3000 yr
kpc^-1, respectively. Both shells have peanut-shaped bipolar structures with
symmetry axes at inclinations of 55 +/- 10 deg (to the line-of-sight) for the
outer shell and 68 +/- 10 deg for the inner shell. The near-alignment between
the nebular shells and the binary orbital inclination (of 68 +/- 2 deg) is
strongly indicative that the binary is responsible for shaping the nebula.
Abell 65 is one of a growing number of planetary nebulae (seven to date,
including Abell 65 itself) for which observations and modelling support the
shaping influence of a central binary.


title:
Oscillations of factorial cumulants to factorial moments ratio from an
  eikonal approach

abstract:
  We study the factorial moments (Fq), the factorial cumulants (Kq) and the
ratio of Kq to Fq (Hq = Kq=Fq) in pp/pp collisions using an updated approach,
in which the multiplicity distribution is related to the eikonal function. The
QCD inspired eikonal model adopted contains contributions of quark-quark,
quark-gluon and gluon-gluon interactions. Our work shows that the approach can
reproduce the collision energy dependence of the Fq moments, correctly predicts
that the first minimum of the Hq lies around q = 5 and qualitatively reproduces
the oscillations of the Hq moments, as shown in the experimental data and
predicted by QCD at preasymptotic energy. The result of this study seems to
indicate that the Hq oscillations are manifestation of semihard component in
the multiparticle production process. Predictions for multiplicity distribution
and Hq moments at the LHC energy of 14 TeV are presented.


title: Renormalization group, trace anomaly and Feynman-Hellmann theorem

abstract:
  We show that the logarithmic derivative of the gauge coupling on the hadronic
mass and the cosmological constant term of a gauge theory are related to the
gluon condensate of the hadron and the vacuum respectively. These relations are
akin to Feynman-Hellmann relations whose derivation for the case at hand are
complicated by the construction of the gauge theory Hamiltonian. We bypass this
problem by using a renormalisation group equation for composite operators and
the trace anomaly. The relations serve as possible definitions of the gluon
condensates themselves which are plagued in direct approaches by power
divergences. In turn these results might help to determine the contribution of
the QCD phase transition to the cosmological constant and test speculative
ideas.


title: Quantum signalling in cavity QED

abstract:
  We consider quantum signalling between two-level quantum systems in a cavity,
in the pertubative regime of the earliest possible arrival times of the signal.
We present two main results: First we find that, perhaps surprisingly, the
analogue of amplitude modulated signalling (Alice using her energy eigenstates
|g>, |e>, as in the Fermi problem) is generally sub-optimal for communication.
Namely, e.g., phase modulated signalling (Alice using, e.g., |+>,|e>-states)
overcomes the quantum noise already at a lower order in perturbation theory.
Second, we study the effect of mode truncations that are commonly used in
cavity QED on the modelling of the communication between two-level atoms. We
show that, on general grounds, namely for causality to be preserved, the UV
cutoff must scale at least polynomially with the desired accuracy of the
predictions.


title: Coupling single molecule magnets to quantum circuits

abstract:
  In this work we study theoretically the coupling of single molecule magnets
(SMMs) to a variety of quantum circuits, including microwave resonators with
and without constrictions and flux qubits. The main results of this study is
that it is possible to achieve strong and ultrastrong coupling regimes between
SMM crystals and the superconducting circuit, with strong hints that such a
coupling could also be reached for individual molecules close to constrictions.
Building on the resulting coupling strengths and the typical coherence times of
these molecules (of the order of microseconds), we conclude that SMMs can be
used for coherent storage and manipulation of quantum information, either in
the context of quantum computing or in quantum simulations. Throughout the work
we also discuss in detail the family of molecules that are most suitable for
such operations, based not only on the coupling strength, but also on the
typical energy gaps and the simplicity with which they can be tuned and
oriented. Finally, we also discuss practical advantages of SMMs, such as the
possibility to fabricate the SMMs ensembles on the chip through the deposition
of small droplets.


title:
Eigenvectors of Sample Covariance Matrices: Universality of global
  fluctuations

abstract:
  In this paper, we prove a universality result of convergence for a bivariate
random process defined by the eigenvectors of a sample covariance matrix. Let
$V_n=(v_{ij})_{i \leq n,\, j\leq m}$ be a $n\times m$ random matrix, where
$(n/m)\to y > 0$ as $ n \to \infty$, and let $X_n=(1/m) V_n V^{*}_n $ be the
sample covariance matrix associated to $V_n \:$. Consider the spectral
decomposition of $X_n$ given by $ U_n D_n U_n^{*}$, where
$U_n=(u_{ij})_{n\times n}$ is an eigenmatrix of $X_n$. We prove, under some
moments conditions, that the bivariate random process $<B_{s,t}^{n} =
\underset{1\leq j \leq \lfloor nt \rfloor}{\sum_{1\leq i \leq \lfloor ns
\rfloor}} <|u_{i,j}|^2 - \frac{1}{n}> >_{(s,t)\in[0,1]^2} $ converges in
distribution to a bivariate Brownian bridge. This type of result has been
already proved for Wishart matrices (LOE/LUE) and Wigner matrices. This
supports the intuition that the eigenmatrix of a sample covariance matrix is in
a way "asymptotically Haar distributed". Our analysis follows closely the one
of Benaych-Georges for Wigner matrices, itself inspired by Silverstein works on
the eigenvectors of sample covariance matrices.


title:
Stellar Populations and the Star Formation Histories of LSB Galaxies:
  II. HII Regions

abstract:
  The luminosities, colors and H\alpha\ emission for 429 HII regions in 54 LSB
galaxies are presented. While the number of HII regions per galaxy is lower in
LSB galaxies compared to star-forming irregulars and spirals, there is no
indication that the size or luminosity function of HII regions differs from
other galaxy types. The lower number of HII regions per galaxy is consistent
with their lower total star formation rates. The fraction of total
$L_{H\alpha}$ contributed by HII regions varies from 10 to 90% in LSB galaxies
(the rest of the H$\alpha$ emission being associated with a diffuse component)
with no correlation with galaxy stellar or gas mass. Bright HII regions have
bluer colors, similar to the trend in spirals; their number and luminosities
are consistent with the hypothesis that they are produced by the same HII
luminosity function as spirals. Comparison with stellar population models
indicates that the brightest HII regions in LSB galaxies range in cluster mass
from a few $10^3 M_{\sun}$ (e.g., $\rho$ Oph) to globular cluster sized systems
(e.g., 30 Dor) and that their ages are consistent with clusters from 2 to 15
Myrs old. The faintest HII regions are comparable to those in the LMC powered
by a single O or B star. Thus, star formation in LSB galaxies covers the full
range of stellar cluster mass.


title: The high-scale SUSY seesaw: LHC vs low energy

abstract:
  In this contribution we outline the correlation between intergenerational
slepton mass splittings and low energy lepton flavour violation in
supersymmetric type-I and type-III seesaws, and illustrate how the combination
of these two sets of observables could strengthen or disfavour a high-scale
seesaw as the explanation of neutrino masses and mixings. This contribution
summarises part of the analysis presented in arXiv:1007.4833 and
arXiv:1104.3962.


title: Towards a Graph-Based Approach for Web Services Composition

abstract:
  Nowadays, Web services (WS) remain a main actor in the implementation of
distributed applications. They represent a new promising paradigm for the
development, deployment and integration of Internet applications. The aim of
Web services composition is to use the skills of several departments to resolve
any problem that cannot be solved individually. The result of this composition
is a compound of Web services that define how they will be used. In this paper,
we propose an approach for automatic web services composition based on the
concepts of directed graphs for the representation and description of Web
services, and the ordering of web services compound execution. In this context,
the user query, defined by a set of inputs and outputs, can be viewed as a
directed graph composed of Web services.


title: Hybrid Textures of the Right-Handed Majorana Neutrino Mass Matrix

abstract:
  We perform a systematic study of neutrino mass matrices having a vanishing
cofactor and an equality between two cofactors of the mass matrix. Such texture
structures of the effective neutrino mass matrix arise from type-I seesaw
mechanism when the Dirac neutrino mass matrix is diagonal with equal elements
and the right-handed Majorana neutrino mass matrix has hybrid textures with one
equality of matrix elements and one zero matrix element. For three right-handed
neutrinos there are sixty possible hybrid textures out of which only six are
excluded by the present experimental data. We show that such textures can be
derived using discrete symmetries. The predictions of experimentally allowed
textures are examined for unknown parameters such as the effective Majorana
mass of the electron neutrino and the Dirac-type CP-violating phase.


title:
Asymmetric Andreev Reflection Induced Electrical and Thermal Hall-like
  Effects in Metal/Anisotropic Superconductor Junctions

abstract:
  By investigating the nonequilibrium transport across a metal/superconductor
junction in both nonrelativistic and relativistic cases, we reveal that the
asymmetric Andreev reflection with anisotropic superconductors is able to
induce the electric and thermal Hall-like effect, in the absence of magnetic
field. That is, a longitudinal electric voltage or temperature bias can induce
transverse electric or thermal currents merely through the asymmetric Andreev
reflection, respectively. In particular, a transverse thermoelectric effect,
i.e., the Ettingshausen-like effect, is identified, although the conjugate
Nernst effect is absent. The direction change of these electric and thermal
Hall-like currents is also discussed. The Hall-like effects uncovered here do
not require the conventional time-reversal symmetry breaking, but rather
originate from the mirror symmetry breaking with respect to the interface
normal due to the anisotropic paring symmetry of the superconductor.


title: Rational curves on quotients of abelian varieties by finite groups

abstract:
  In [3], it is proved that the quotient of an abelian variety $A$ by a finite
order automorphism $g$ is uniruled if and only if some power of $g$ satisfies a
numerical condition $0<\age(g^k)<1$. In this paper, we show that $\age(g^k)=1$
is enough to guarantee that $A/\langle g\rangle$ has at least one rational
curve.


title:
Absolutely Continuous Convolutions of Singular Measures and an
  Application to the Square Fibonacci Hamiltonian

abstract:
  We prove for the square Fibonacci Hamiltonian that the density of states
measure is absolutely continuous for almost all pairs of small coupling
constants. This is obtained from a new result we establish about the absolute
continuity of convolutions of measures arising in hyperbolic dynamics with
exact-dimensional measures.


title: Structure of the group preserving a bilinear form

abstract:
  We study the group of all linear automorphisms preserving an arbitrary
bilinear form


title: Rings associated to coverings of finite p-groups

abstract:
  In general the endomorphisms of a non-abelian group do not form a ring under
the operations of addition and composition of functions. Several papers have
dealt with the ring of functions defined on a group which are endomorphisms
when restricted to the elements of a cover of the group by abelian subgroups.
We give an algorithm which allows us to determine the elements of the ring of
functions of a finite $p$-group which arises in this manner when the elements
of the cover are required to be either cyclic or elementary abelian of rank
$2$. This enables us to determine the actual structure of such a ring as a
subdirect product. A key part of the argument is the construction of a graph
whose vertices are the subgroups of order $p$ and whose edges are determined by
the covering.


title: Succinct data structures for representing equivalence classes

abstract:
  Given a partition of an n element set into equivalence classes, we consider
time-space tradeoffs for representing it to support the query that asks whether
two given elements are in the same equivalence class. This has various
applications including for testing whether two vertices are in the same
component in an undirected graph or in the same strongly connected component in
a directed graph.
  We consider the problem in several models.
  -- Concerning labeling schemes where we assign labels to elements and the
query is to be answered just by examining the labels of the queried elements
(without any extra space): if each vertex is required to have a unique label,
then we show that a label space of (\sum_{i=1}^n \lfloor {n \over i} \rfloor)
is necessary and sufficient. In other words, \lg n + \lg \lg n + O(1) bits of
space are necessary and sufficient for representing each of the labels. This
slightly strengthens the known lower bound and is in contrast to the known
necessary and sufficient bound of \lceil \lg n \rceil for the label length, if
each vertex need not get a unique label.
  --Concerning succinct data structures for the problem when the n elements are
to be uniquely assigned labels from label set {1, 2, ...n}, we first show that
\Theta(\sqrt n) bits are necessary and sufficient to represent the equivalence
class information. This space includes the space for implicitly encoding the
vertex labels. We can support the query in such a structure in O(\lg n) time in
the standard word RAM model. We then develop structures resulting in one where
the queries can be supported in constant time using O({\sqrt n} \lg n) bits of
space. We also develop space efficient structures where union operation along
with the equivalence query can be answered fast.


title:
Composition series of $\gl(m)$ as a module for its classical subalgebras
  over an arbitrary field

abstract:
  Let $F$ be an arbitrary field and let $f:V\times V\to F$ be a non-degenerate
symmetric or alternating bilinear form defined on an $F$-vector space of finite
dimension $m\geq 2$. Let $L(f)$ be the subalgebra of $gl(V)$ formed by all
skew-adjoint endomorphisms with respect to $f$. We find a composition series
for the $L(f)$-module $gl(V)$ and furnish multiple identifications for all its
composition factors.


title: On the number of irreducible points in polyhedra

abstract:
  An integer point in a polyhedron is called irreducible iff it is not the
midpoint of two other integer points in the polyhedron. We prove that the
number of irreducible integer points in $n$-dimensional polytope with radius
$k$ given by a system of $m$ linear inequalities is at most
$O(m^{\lfloor\frac{n}{2}\rfloor}\log^{n-1} k)$ if $n$ is fixed. Using this
result we prove the hypothesis asserting that the teaching dimension in the
class of threshold functions of $k$-valued logic in $n$ variables is
$\Theta(\log^{n-2} k)$ for any fixed $n\ge 2$.


title: Modular representations of Heisenberg algebras

abstract:
  Let $F$ be be an arbitrary field and let $h(n)$ be the Heisenberg algebra of
dimension $2n+1$ over $F$. It was shown by Burde that if $F$ has characteristic
0 then the minimum dimension of a faithful $h(n)$-module is $n+2$. We show here
that his result remains valid in prime characteristic $p$, as long as
$(p,n)\neq (2,1)$.
  We construct, as well, various families of faithful irreducible
$h(n)$-modules if $F$ has prime characteristic, and classify these when $F$ is
algebraically closed. Applications to matrix theory are given.


title:
On interval based generalizations of absolute continuity for functions
  on $\mathbb{R}^n$

abstract:
  We study notions of absolute continuity for functions defined on
$\mathbb{R}^n$similar to the notion of $\alpha$-absolute continuity in the
sense of Bongiorno. We confirm a conjecture of Mal\'y that 1-absolutely
continuous functions do not need to be differentiable a.e., and we show several
other pathological examples of functions in this class. We establish
containment relations of the class $1-AC_{\rm WDN}$ which consits of all
functions in $1-AC$ which are in the Sobolev space $W^{1,2}_{loc}$, are
differentiable a.e. and satisfy the Luzin (N) property, with previously studied
classes of absolutely continuous functions.


title:
Magnon, phonon and electron temperature profiles and the spin Seebeck
  effect in magnetic insulator/normal metal hybrid structures

abstract:
  We calculate the phonon, electron and magnon temperature profiles in yttrium
iron garnet/platinum bilayers by diffusive theory with appropriate boundary
conditions, in particular taking into account interfacial thermal resistances.
Our calculations show that in thin film hybrids, the interface magnetic heat
conductance qualitatively affects the magnon temperature. Based on published
material parameters we assess the degree of non-equilibrium at the yttrium iron
garnet/platinum interface. The magnitude of the spin Seebeck effect derived
from this approach compares well with experimental results for the longitudinal
spin Seebeck effect. Additionally we address the temperature profiles in the
transverse spin Seebeck effect.


title: Tidal evolution of close-in exoplanets in co-orbital configurations

abstract:
  In this paper, we study the behavior of a pair of co-orbital planets, both
orbiting a central star on the same plane and undergoing tidal interactions.
Our goal is to investigate final orbital configurations of the planets,
initially involved in the 1/1 mean-motion resonance (MMR), after long-lasting
tidal evolution. The study is done in the form of purely numerical simulations
of the exact equations of motions accounting for gravitational and tidal
forces. The results obtained show that, at least for equal mass planets, the
combined effects of the resonant and tidal interactions provoke the orbital
instability of the system, often resulting in collision between the planets. We
first discuss the case of two hot-super-Earth planets, whose orbital dynamics
can be easily understood in the frame of our semi-analytical model of the 1/1
MMR. Systems consisting of two hot-Saturn planets are also briefly discussed.


title: Relations in universal Lie nilpotent associative algebras of class 4

abstract:
  Let $K$ be a unital associative and commutative ring and let $K \langle X
\rangle$ be the free unital associative $K$-algebra on a non-empty set $X$ of
free generators. Define a left-normed commutator $[a_1, a_2, \dots , a_n]$
inductively by $[a_1, a_2] = a_1 a_2 - a_2 a_1$, $[a_1, \dots , a_{n-1}, a_n] =
[[a_1, \dots , a_{n-1}], a_n]$ $(n \ge 3)$. For $n \ge 2$, let $T^{(n)}$ be the
two-sided ideal in $K \langle X \rangle$ generated by all commutators
$[a_1,a_2, \dots , a_n]$ $( a_i \in K \langle X \rangle )$.
  It can be easily seen that the ideal $T^{(2)}$ is generated (as a two-sided
ideal in $K \langle X \rangle$) by the commutators $[x_1, x_2]$ $(x_i \in X)$.
It is well-known that $T^{(3)}$ is generated by the polynomials $[x_1,x_2,x_3]$
and $[x_1,x_2][x_3,x_4] + [x_1,x_3][x_2,x_4]$ $(x_i \in X)$. A similar
generating set for $T^{(4)}$ contains 3 types of polynomials in $x_i \in X$ if
$\frac{1}{3} \in K$ and 5 types if $\frac{1}{3} \notin K$. In the present
article we exhibit a generating set for $T^{(5)}$ that contains 8 types of
polynomials in $x_i \in X$.


title:
Some properties for quaternionic slice-regular functions on domains
  without real points

abstract:
  The theory of slice regular functions over the quaternions, introduced by
Gentili and Struppa in [5], was born on domains that intersect the real axis.
This hypothesis can be overcome using the theory of stem functions introduced
by Ghiloni and Perotti ([6]), in the context of real alternative algebras. In
this paper I will recall the notion and the main properties of stem functions.
After that I will introduce the class of slice regular functions induced by
stem functions and, in this set, I will extend the identity principle, the
maximum and minimum modulus principles and the open mapping theorem.
Differences will be shown between the case when the domain does or does not
intersect the real axis.


title:
Exactly solvable model of the ferroelectrics hysteresis loops control by
  the external electric field

abstract:
  The kinetic theory of switching processes in crystalline ferroelectric
materials under the influence of a variable external electric field is
formulated. The basic equations are derived and their exact analytical solution
at arbitrary time-dependent external field are obtained. Connection between the
hysteresis loops shape and variable external electric field parameters is
investigated numerically. The numerical results were found to be in excellent
agreement with the experiments. PACS: 77.80.Fm, 77.80.Dj, 77.80.-e Keywords:
ferroelectrics, switching processes, hysteresis curves, polarization


title: ABJM Wilson Loops in Arbitrary Representations

abstract:
  We study vacuum expectation values (VEVs) of circular half BPS Wilson loops
in arbitrary representations in ABJM theory. We find that those in hook
representations are reduced to elementary integrations thanks to the Fermi gas
formalism, which are accessible from the numerical studies similar to the
partition function in the previous studies. For non-hook representations, we
show that the VEVs in the grand canonical formalism can be exactly expressed as
determinants of those in the hook representations. Using these facts, we can
study the instanton effects of the VEVs in various representations. Our results
are consistent with the worldsheet instanton effects studied from the
topological string and a prescription to include the membrane instanton effects
by shifting the chemical potential, which has been successful for the partition
function.


title: Framing the Di-Logarithm (over Z)

abstract:
  Motivated by their role for integrality and integrability in topological
string theory, we introduce the general mathematical notion of "s-functions" as
integral linear combinations of poly-logarithms. 2-functions arise as disk
amplitudes in Calabi-Yau D-brane backgrounds and form the simplest and most
important special class. We describe s-functions in terms of the action of the
Frobenius endomorphism on formal power series and use this description to
characterize 2-functions in terms of algebraic K-theory of the completed power
series ring. This characterization leads to a general proof of integrality of
the framing transformation, via a certain orthogonality relation in K-theory.
We comment on a variety of possible applications. We here consider only power
series with rational coefficients; the general situation when the coefficients
belong to an arbitrary algebraic number field is treated in a companion paper.


title:
alpha-Kuramoto partitions: graph partitions from the frustrated Kuramoto
  model generalise equitable partitions

abstract:
  The Kuramoto model describes the collective dynamics of a system of coupled
oscillators. An alpha-Kuramoto partition is a graph partition induced by the
Kuramoto model, when the oscillators include a phase frustration parameter. We
prove that every equitable partition is an alpha-Kuramoto partition, but that
the converse does necessarily not hold. We give an exact characterisation of
alpha-Kuramoto bipartitions.


title: Magnetic Dynamics of a Multiferroic with an Antiferromagnetic Layer

abstract:
  Shape effects in magnetic particles are widely studied, because of the
ability of the shape and the size to control the parameters of a sample during
its production. Experiments with nano-sized samples show that the shape can
affect also the properties of antiferromagnetic (AFM) materials. However, the
theoretical interpretation of these effects is under discussion. We propose a
model to study the shape-induced effects in AFM particles at the AFM resonance
frequency. The Lagrange function method is used to calculate the spectrum of
resonance oscillations of the AFM vector in a synthetic multiferroic
(piezoelectric + antiferromagnet). The influence of the specimen shape on the
AFM resonance frequency in the presence of an external magnetic field is
studied. Conditions for a resonance under the action of an external force or
for a parametric resonance to arise in the magnetic subsystem are considered.


title:
Bright solitons in quasi-one dimensional dipolar condensates with
  spatially modulated interactions

abstract:
  We introduce a model for the condensate of dipolar atoms or molecules, in
which the dipole-dipole interaction (DDI) is periodically modulated in space,
due to a periodic change of the local orientation of the permanent dipoles,
imposed by the corresponding structure of an external field (the necessary
field can be created, in particular, by means of magnetic lattices, which are
available to the experiment). The system represents a realization of a nonlocal
nonlinear lattice, which has a potential to support various spatial modes. By
means of numerical methods and variational approximation (VA), we construct
bright one-dimensional solitons in this system, and study their stability. In
most cases, the VA provides good accuracy, and correctly predicts the stability
by means of the Vakhitov-Kolokolov (VK)\ criterion. It is found that the
periodic modulation may destroy some solitons, which exist in the usual setting
with unmodulated DDI, and can create stable solitons in other cases, not
verified in the absence of modulations. Unstable solitons typically transform
into persistent localized breathers. The solitons are often mobile, with
inelastic collisions between them leading to oscillating localized modes.


title: Network bargaining with general capacities

abstract:
  We study balanced solutions for network bargaining games with general
capacities, where agents can participate in a fixed but arbitrary number of
contracts. We provide the first polynomial time algorithm for computing
balanced solutions for these games. In addition, we prove that an instance has
a balanced solution if and only if it has a stable one. Our methods use a new
idea of reducing an instance with general capacities to a network bargaining
game with unit capacities defined on an auxiliary graph. This represents a
departure from previous approaches, which rely on computing an allocation in
the intersection of the core and prekernel of a corresponding cooperative game,
and then proving that the solution corresponding to this allocation is
balanced. In fact, we show that such cooperative game methods do not extend to
general capacity games, since contrary to the case of unit capacities, there
exist allocations in the intersection of the core and prekernel with no
corresponding balanced solution. Finally, we identify two sufficient conditions
under which the set of balanced solutions corresponds to the intersection of
the core and prekernel, thereby extending the class of games for which this
result was previously known.


title:
Distributed conjugate gradient strategies for parameter estimation over
  sensor networks

abstract:
  This paper presents distributed adaptive algorithms based on the conjugate
gradient (CG) method for distributed networks. Both incremental and diffusion
adaptive solutions are all considered. The distributed conventional (CG) and
modified CG (MCG) algorithms have an improved performance in terms of mean
square error as compared with least-mean square (LMS)-based algorithms and a
performance that is close to recursive least-squares (RLS) algorithms . The
resulting algorithms are distributed, cooperative and able to respond in real
time to changes in the environment.


title: Sheaves of categories and the notion of 1-affineness

abstract:
  We define the notion of 1-affineness for a prestack, and prove an array of
results that establish 1-affineness of certain types of prestacks.


title:
Interplay of the electronic and lattice degrees of freedom in
  A_{1-x}Fe_{2-y}Se_{2} superconductors under pressure

abstract:
  The local structure and electronic properties of Rb$_{1-x}$Fe$_{2-y}$Se$_2$
are investigated by means of site selective polarized x-ray absorption
spectroscopy at the iron and selenium K-edges as a function of pressure. A
combination of dispersive geometry and novel nanodiamond anvil pressure-cell
has permitted to reveal a step-like decrease in the Fe-Se bond distance at
$p\simeq11$ GPa. The position of the Fe K-edge pre-peak, which is directly
related to the position of the chemical potential, remains nearly constant
until $\sim6$ GPa, followed by an increase until $p\simeq 11$ GPa. Here, as in
the local structure, a step-like decrease of the chemical potential is seen.
Thus, the present results provide compelling evidence that the origin of the
reemerging superconductivity in $A_{1-x}$Fe$_{2-y}$Se$_2$ in vicinity of a
quantum critical transition is caused mainly by the changes in the electronic
structure.


title: Ballistic spreading of entanglement in a diffusive nonintegrable system

abstract:
  We study the time evolution of the entanglement entropy of a one-dimensional
nonintegrable spin chain, starting from random nonentangled initial pure
states. We use exact diagonalization of a nonintegrable quantum Ising chain
with transverse and longitudinal fields to obtain the exact quantum dynamics.
We show that the entanglement entropy increases linearly with time before
finite-size saturation begins, demonstrating a ballistic spreading of the
entanglement, while the energy transport in the same system is diffusive. Thus
we explicitly demonstrate that the spreading of entanglement is much faster
than the energy diffusion in this nonintegrable system.


title:
Micro- and macroturbulence predictions from CO5BOLD 3D stellar
  atmospheres

abstract:
  We present an overview of the current status of our efforts to derive the
microturbulence and macroturbulence parameters (ximic and ximac) from the
CIFIST grid of CO5BOLD 3D model atmospheres as a function of the basic stellar
parameters Teff, log g, and [M/H]. The latest results for the Sun and Procyon
show that the derived microturbulence parameter depends significantly on the
numerical resolution of the underlying 3D simulation, confirming that
`low-resolution' models tend to underestimate the true value of ximic.
Extending the investigation to twelve further simulations with different Teff,
log g, and [M/H], we obtain a first impression of the predicted trend of ximic
over the Hertzsprung-Russell diagram: in agreement with empirical evidence,
microturbulence increases towards higher effective temperature and lower
gravity. The metallicity dependence of ximic must be interpreted with care,
since it also reflects the deviation between the 1D and 3D photospheric
temperature stratifications that increases systematically towards lower
metallicity.


title: V\'erification Formelle des Processus Workflow Collaboratifs

abstract:
  In this paper, we present a method of verification of collaborative workflow
processes based on model checking techniques. In particular, we propose to
verify soundness properties of these processes using SPIN model checker. First
we translate the adopted specification of workflows (i.e. the WF-net) to
Promela which is the description language of models to be verified by SPIN.
Then we express the soundness properties in Linear Temporal Logic (LTL) and use
SPIN to test whether each property is satisfied by the Promela model of the
WF-net in question. Finally, we express the properties of k-soundness for
WF-nets modeling multiple instances and (k,R)-soundness for workflow processes
with multiple instances and sharing resources.


title:
Gas-surface interaction and boundary conditions for the Boltzmann
  equation

abstract:
  In this paper we revisit the derivation of boundary conditions for the
Boltzmann Equation. The interaction between the wall atoms and the gas
molecules within a thin surface layer is described by a kinetic equation
introduced in [9] and used in [1]. This equation includes a Vlasov term and a
linear molecule-phonon collision term and is coupled with the Boltzmann
equation describing the evolution of the gas in the bulk flow. Boundary
conditions are formally derived from this model by using classical tools of
kinetic theory such as scaling and systematic asymptotic expansion. In a first
step this method is applied to the simplified case of a flat wall. Then it is
extented to walls with nanoscale roughness allowing to obtain more complex
scattering patterns related to the morphology of the wall. It is proved that
the obtained scattering kernels satisfy the classical imposed properties of
non-negativeness, normalization and reciprocity introduced by Cercignani [11].


title: What is a photon?

abstract:
  We discuss the absorber theory of radiation as put forward by Wheeler and
Feynman. We show that it gives a better understanding of the photon compared to
the usual quantum electrodynamics (QED) picture.


title: Macroscopic quantum-type potentials in scale relativity

abstract:
  We review in this paper the use of the theory of scale relativity and fractal
space-time as a tool particularly well adapted to the possible development of a
future genuine theoretical systems biology. We emphasize in particular the
concept of quantum-type potentials, since in many situations the effect of the
fractality of space -- or of the underlying medium -- amounts to the addition
of such a potential energy to the classical equations of motion. Various
equivalent representations -- geodesic, quantum, fluid mechanical, stochastic
-- of these equations are given, as well as several forms of generalized
quantum potentials. Examples of their possible intervention in high critical
temperature superconductivity and in turbulence are also described, since some
biological processes may be analog in some aspects to these physical phenomena.
These potential energy extra contributions could have emerged in biology from
the very fractal nature of the medium, or from an evolutive advantage, since
they involve spontaneous properties of self-organization, morphogenesis
structuration and multi-scale integration.


title:
Dust in the polar region as a major contributor to the IR emission of
  AGN

abstract:
  (abridged) It is generally assumed that the distribution of dust on parsec
scales forms a geometrically- and optically-thick entity in the equatorial
plane around the accretion disk and broad-line region - dubbed "dust torus" -
that emits the bulk of the sub-arcsecond-scale IR emission and gives rise to
orientation-dependent obscuration. Here we report detailed interferometry
observations of the unobscured (type 1) AGN in NGC 3783 that allow us to
constrain the size, elongation, and direction of the mid-IR emission with high
accuracy. The mid-IR emission is characterized by a strong elongation toward
position angle PA -52 deg, closely aligned with the polar axis (PA -45 deg). We
determine half-light radii along the major and minor axes at 12.5 {\mu}m of
(4.23 +/- 0.63) pc x (1.42 +/- 0.21) pc, which corresponds to
intrinsically-scaled sizes of (69.4 +/- 10.8) rin x (23.3 +/- 3.5) rin for the
inner dust radius of rin = 0.061 pc as inferred from near-IR reverberation
mapping. This implies an axis ratio of 3:1, with about 60-90% of the 8-13
{\mu}m emission associated with the polar-elongated component. These
observations are difficult to reconcile with the standard interpretation that
most of the parsec-scale mid-IR emission in AGN originates from the torus and
challenges the justification of using simple torus models to model the
broad-band IR emission. It is quite likely that the hot-dust emission in NGC
3783 as recently resolved by near-IR interferometry is misaligned with the
mid-IR emitting source, which also finds a correspondence in the two distinct
3-5 {\mu}m and 20 {\mu}m bumps seen in the high-angular resolution spectral
energy distribution (SED). We conclude that these observations support a
scenario where the majority of the mid-IR emission in Seyfert AGN originates
from a dusty wind in the polar region of the AGN.


title:
Efficient and accurate surface hopping for long time nonadiabatic
  quantum dynamics

abstract:
  The quantum-classical Liouville equation offers a rigorous approach to
nonadiabatic quantum dynamics based on surface hopping type trajectories.
However, in practice the applicability of this approach has been limited to
short times owing to unfavorable numerical scaling. In this paper we show that
this problem can be alleviated by combining it with a formally exact
generalized quantum master equation treatment. This allows dramatic
improvements in the efficiency of the approach in nonadiabatic regimes, making
it computationally tractable to treat the quantum dynamics of complex systems
for long times. We demonstrate our approach by applying it to a model of
condensed phase charge transfer where our method is shown to be numerically
exact in regimes where fewest-switches surface hopping and mean field
approaches fail to obtain the either the correct rates or long-time
populations.


title: Exotic Top Partners and Little Higgs

abstract:
  Little Higgs models often give rise to top partners beyond the minimal ones
necessary for the cancellation of quadratic divergences. We review how this
occurs and discuss the phenomenology of these exotic states. We emphasize the
possible importance of new pseudo-Nambu-Goldstone bosons in top partner decays.
Indeed, cascade decays of exotic top partners may be the best way to discover
these new bosons. We illustrate these points with a new Little Higgs
construction based on an SO(10)/SO(5)^2 coset structure, which fills a gap in
the model building literature. These observations motivate new search
strategies for top partners at the LHC, including for final states with b-jets
and a large multiplicity of electroweak bosons.


title:
The Two Dimensional Projected Spatial Distribution of Globular Clusters:
  Method and Application to NGC4261

abstract:
  We present a new method for the determination of the two-dimensional (2D)
projected spatial distribution of globular clusters (GCs) in external galaxies.
This method is based on the K-Nearest Neighbor density estimator of Dressler
(1980), complemented by MonteCarlo simulations to establish the statistical
significance of the results. We apply this method to NGC4261, a "test galaxy"
where significant 2D anisotropy in the GC distribution has been reported. We
confirm that the 2D distribution of GC is not azimuthally isotropic. Moreover,
we demonstrate that the 2D distribution departures from the average GC radial
distribution results in highly significant spiral-like or broken shell
features. Overall, the same perturbations are found in "red" and "blue" GCs,
but with some differences. In particular, we observe a central feature, roughly
aligned with the minor axis of NGC4261, composed of red and most luminous GCs.
Blue and fainter GCs are more frequent at large radial distances and follow the
spiral-like features of the overall density structure. These results suggest a
complex merging history for NGC4261.


title:
The Effect of Partial Obscuration on the Luminosity Dependence of the
  Obscured Fraction in Active Galactic Nuclei

abstract:
  Surveys of Active Galactic Nuclei (AGN) in different observational regimes
seem to give different answers for the behaviour of the obscured fraction with
luminosity. Based on the complex spectra seen in recent studies, we note that
partial covering could significantly change the apparent luminosities of many
AGN, even after apparent X-ray absorption correction. We explore whether this
effect could reproduce the observed dependence of the obscured fraction on the
apparent X-ray luminosities seen between 2--10 keV. We can reproduce the
observed trend in a model where 33 per cent of AGN are unobscured, 30 per cent
are heavily buried, and 37 per cent have a range of intermediate partial
coverings. Our model is also tentatively successful at reproducing observed
trends in the X-ray vs. infrared luminosity ratio for AGN.


title: Clumps and triggered star formation in ionised molecular clouds

abstract:
  Infrared shells and bubbles are ubiquitous in the Galaxy and can generally be
associated with HII regions formed around young, massive stars. In this paper,
we use high-resolution 3D SPH simulations to explore the effect of a single O7
star emitting photons at 10^49 1/s and located at the centre of a molecular
cloud with mass 10^4 M_sun and radius 6.4 pc; the internal structure of the
cloud is characterised by its fractal dimension, D (with 2.0 <= D <= 2.8), and
the variance of its (log-normal) density distribution, sigma_0^2 (with 0.36 <=
sigma_0^2 <= 1.42). Our study focuses on the morphology of the swept-up cold
gas and the distribution and statistics of the resulting star formation. If the
fractal dimension is low, the border of the HII region is dominated by extended
shell-like structures, and these break up into a small number of massive
high-density clumps which then spawn star clusters; star formation occurs
relatively quickly, and delivers somewhat higher stellar masses. Conversely, if
the fractal dimension is high, the border of the HII region is dominated by a
large number of pillars and cometary globules, which contain compact dense
clumps and tend to spawn single stars or individual multiple systems; star
formation occurs later, the stellar masses are somewhat lower, and the stars
are more widely distributed.

categories: astro-ph.GA astro-ph.CO astro-ph.EP astro-ph.SR


title:
Non-Axisymmetric Instability of Rotating Black Holes in Higher
  Dimensions

abstract:
  We calculate the scalar-gravitational quasi-normal modes of equal angular
momenta Myers-Perry black holes in odd dimensions. We find a new bar-mode
(non-axisymmetric) classical instability for $D \ge 7$. These black holes were
previously found to be unstable to axisymmetric perturbations for spins very
near extremality. The bar-mode instability we find sets in at much slower
spins, and is therefore the dominant instability of these black holes. This
instability has important consequences for the phase diagram of black holes in
higher dimensions.


title:
Baryons do trace dark matter 380,000 years after the big bang: Search
  for compensated isocurvature perturbations with WMAP 9-year data

abstract:
  Primordial isocurvature fluctuations between photons and either neutrinos or
non-relativistic species such as baryons or dark matter are known to be
sub-dominant to adiabatic fluctuations. Perturbations in the relative densities
of baryons and dark matter (known as compensated isocurvature perturbations, or
CIPs), however, are surprisingly poorly constrained. CIPs leave no imprint in
the cosmic microwave background (CMB) on observable scales, at least at linear
order in their amplitude and zeroth order in the amplitude of adiabatic
perturbations. It is thus not yet empirically known if baryons trace dark
matter at the surface of last scattering. If CIPs exist, they would spatially
modulate the Silk damping scale and acoustic horizon, causing distinct
fluctuations in the CMB temperature/polarization power spectra across the sky:
this effect is first order in both the CIP and adiabatic mode amplitudes. Here,
temperature data from the Wilkinson Microwave Anisotropy Probe (WMAP) are used
to conduct the first CMB-based observational search for CIPs, using
off-diagonal correlations and the CMB trispectrum. Reconstruction noise from
weak lensing and point sources is shown to be negligible for this data set. No
evidence for CIPs is observed, and a 95%-confidence upper limit of $1.1\times
10^{-2}$ is imposed to the amplitude of a scale-invariant CIP power spectrum.
This limit agrees with CIP sensitivity forecasts for WMAP, and is competitive
with smaller scale constraints from measurements of the baryon fraction in
galaxy clusters. It is shown that the root-mean-squared CIP amplitude on 5-100
degree scales is smaller than 0.07-0.17 (depending on the scale) at the
95%-confidence level. Temperature data from the Planck satellite will provide
an even more sensitive probe for the existence of CIPs, as will the upcoming
ACTPol and SPTPol experiments on smaller angular scales.


title: Fivebranes and 4-manifolds

abstract:
  We describe rules for building 2d theories labeled by 4-manifolds. Using the
proposed dictionary between building blocks of 4-manifolds and 2d N=(0,2)
theories, we obtain a number of results, which include new 3d N=2 theories
T[M_3] associated with rational homology spheres and new results for
Vafa-Witten partition functions on 4-manifolds. In particular, we point out
that the gluing measure for the latter is precisely the superconformal index of
2d (0,2) vector multiplet and relate the basic building blocks with coset
branching functions. We also offer a new look at the fusion of defect lines /
walls, and a physical interpretation of the 4d and 3d Kirby calculus as
dualities of 2d N=(0,2) theories and 3d N=2 theories, respectively


title: Electroweak Cogenesis

abstract:
  We propose a simple renormalizable model of baryogenesis and asymmetric dark
matter generation at the electroweak phase transition. Our setup utilizes the
two Higgs doublet model plus two complex gauge singlets, the lighter of which
is stable dark matter. The dark matter is charged under a global symmetry that
is broken in the early universe but restored during the electroweak phase
transition. Because the ratio of baryon and dark matter asymmetries is
controlled by model parameters, the dark matter need not be light. Thus, new
force carriers are unnecessary and the symmetric dark matter abundance can be
eliminated via Higgs portal interactions alone. Our model places a rough upper
bound on the dark matter mass, and has implications for direct detection
experiments and particle colliders.


title:
NPOI Observations of the Exoplanet Host kappa Coronae Borealis and Their
  Implications for the Star's and Planet's Masses and Ages

abstract:
  We used the Navy Precision Optical Interferometer to measure the
limb-darkened angular diameter of the exoplanet host star kappa CrB and
obtained a value of 1.543 +/- 0.009 mas. We calculated its physical radius
(5.06 +/- 0.04 R_Sun) and used photometric measurements from the literature
with our diameter to determine kappa CrB's effective temperature (4788 +/- 17
K) and luminosity (12.13 +/- 0.09 L_Sun). We then placed the star on an H-R
diagram to ascertain the star's age (3.42 +0.32/-0.25 Gyr) and mass (1.47 +/-
0.04 M_Sun) using a metallicity of [Fe/H] = +0.15. With this mass, we
calculated the system's mass function with the orbital elements from a variety
of sources, which produced a range of planetary masses: m_p sin i = 1.61 to
1.88 M_Jup. We also updated the extent of the habitable zone for the system
using our new temperature.


title:
Tests of the asymptotic large frequency separation of acoustic
  oscillations in solar-type and red giant stars

abstract:
  Asteroseismology, i.e. the study of the internal structures of stars via
their global oscillations, is a valuable tool to obtain stellar parameters such
as mass, radius, surface gravity and mean density. These parameters can be
obtained using certain scaling relations which are based on an asymptotic
approximation. Usually the observed oscillation parameters are assumed to
follow these scaling relations. Recently, it has been questioned whether this
is a valid approach, i.e., whether the order of the observed oscillation modes
are high enough to be approximated with an asymptotic theory. In this work we
use stellar models to investigate whether the differences between observable
oscillation parameters and their asymptotic estimates are indeed significant.
We compute the asymptotic values directly from the stellar models and derive
the observable values from adiabatic pulsation calculations of the same models.
We find that the extent to which the atmosphere is included in the models is a
key parameter. Considering a larger extension of the atmosphere beyond the
photosphere reduces the difference between the asymptotic and observable values
of the large frequency separation. Therefore, we conclude that the currently
suggested discrepancies in the scaling relations might have been overestimated.
Hence, based on the results presented here we believe that the suggestions of
Mosser et al. (2013) should not be followed without careful consideration.


title: Global properties of causal wedges in asymptotically AdS spacetimes

abstract:
  We examine general features of causal wedges in asymptotically AdS spacetimes
and show that in a wide variety of cases they have non-trivial topology. We
also prove some general results regarding minimal area surfaces on the causal
wedge boundary and thereby derive constraints on the causal holographic
information. We go on to demonstrate that certain properties of the causal
wedge impact significantly on features of extremal surfaces which are relevant
for computation of holographic entanglement entropy.


title:
Dynamical and collisional constraints on a stochastic late veneer on the
  terrestrial planets

abstract:
  Given their tendency to be incorporated into the core during differentiation,
the highly-siderophile elements (HSEs) in Earth's mantle are thought to have
been accreted as a `late veneer' after the end of the giant impact phase.
Bottke et al (2010) proposed that the large Earth-to-Moon HSE abundance ratio
can be explained if the late veneer was characterized by large (D =
1000-4000km) impactors. Here we simulate the evolution of the terrestrial
planets during a stochastic late veneer phase from the end of accretion until
the start of the late heavy bombardment ~500 Myr later. We show that a late
veneer population of 0.05 Earth masses dominated by large (D > 1000km) bodies
naturally delivers a ~0.01 Earth mass veneer to Earth, consistent with
constraints. The eccentricities and inclinations of the terrestrial planets are
excited by close encounters with the largest late veneer bodies. We find the
best agreement with their post-veneer orbits if either a) the terrestrial
planets' pre-veneer angular momentum deficit AMD_0 was less than half of the
current one AMD_now, or b) AMD_0 <= AMD_now and the veneer was limited to
smaller (D_max <= 2000km) bodies. Veneer impacts on Venus, Earth and Mars were
mostly accretionary but on Mercury and the Moon they were mostly erosive. In
~20% of simulations an energetic impact occurred that could have removed >25%
of Mercury's mass, thereby increasing its iron mass fraction. We show that, due
to the erosive nature of larger impacts, the Moon cannot accrete any material
from objects larger than 500-1000km. The large Earth-to-Moon HSE abundance
ratio is explained if the late veneer included large impactors (D >=
500-1000km) regardless of their size distribution, as long as most of Earth's
veneer came from large bodies. The spin angular momenta imparted by stochastic
late veneer impacts was far in excess of the current ones for Mercury and
Venus.


title: Chameleon Field Theories

abstract:
  Chameleons are light scalar fields with remarkable properties. Through the
interplay of self-interactions and coupling to matter, chameleon particles have
a mass that depends on the ambient matter density. The manifestation of the
fifth force mediated by chameleons therefore depends sensitively on their
environment, which makes for a rich phenomenology. In this article, we review
two recent results on chameleon phenomenology. The first result a pair of no-go
theorems limiting the cosmological impact of chameleons and their
generalizations: i) the range of the chameleon force at cosmological density
today can be at most ~Mpc; ii) the conformal factor relating Einstein- and
Jordan-frame scale factors is essentially constant over the last Hubble time.
These theorems imply that chameleons have negligible effect on the linear
growth of structure, and cannot account for the observed cosmic acceleration
except as some form of dark energy. The second result pertains to the quantum
stability of chameleon theories. We show how requiring that quantum corrections
be small, so as to allow reliable predictions of fifth forces, leads to an
upper bound of m < 0.0073 (\rho/ 10 g cm^{-3})^{1/3} eV for gravitational
strength coupling, whereas fifth force experiments place a lower bound of
m>0.0042 eV. An improvement of less than a factor of two in the range of fifth
force experiments could test all classical chameleon field theories whose
quantum corrections are well-controlled and couple to matter with nearly
gravitational strength regardless of the specific form of the chameleon
potential.


title:
Modelling the Growth of Supermassive Black Holes in Cosmological
  Simulations

abstract:
  There is strong evidence that supermassive black holes reside in all galaxies
that contain a stellar spheroid and their mass is tightly correlated with
properties such as stellar bulge mass and velocity dispersion. There are also
strong theoretical arguments that feedback from supermassive black holes plays
an important role in shaping the high mass end of the galaxy mass function,
hence to accurately model galaxies we also need to model the black holes. We
present a comparison of two black hole growth models implemented within a
large-scale, cosmological SPH simulation including star formation and feedback.
One model is a modified Bondi-Hoyle prescription that grows black holes based
on the smooth density of local gas, while the other is the recently proposed
Accretion Disc Particle (ADP) method. This model swallows baryonic particles
that pass within an accretion radius of the black hole and adds them to a
subgrid accretion disc. Black holes are then grown by material from this disc.
We find that both models can reproduce local scaling relations, although the
ADP model is offset from the observed relations at high black hole masses. The
total black hole mass density agrees between models to within a factor of
three, but both struggle to reproduce the black hole mass function. The
simulated mass functions are too steep and underestimate the number of
intermediate and high mass black holes. In addition, the ADP model swallows
excessive amounts of material at the resolution of large-scale, cosmological
simulations producing unrealistically large accretion discs. Future work needs
to be performed to improve the black hole mass function within simulations.
This should be done through the mass growth and feedback as they are strongly
coupled and should not be treated as separate entities.


title: The Massive Satellite Population of Milky-Way Sized Galaxies

abstract:
  Several occupational distributions for satellite galaxies more massive than
ms~4E7 Msun around MW-sized hosts are presented and used to predict their
internal dynamics. For this, a galaxy group mock catalog is constructed on the
basis of (sub)halo-to-stellar mass relations constrained with the observed
Galaxy Stellar Mass Function decomposed into centrals and satellites, and the
2-point correlation functions. For the MW-sized hosts we find that: 6.6% have 2
satellites in the SMC-LMC mass range; their probabilities to have 1, 2 or 3
satellites equal or larger than the LMC, the SMC or Sgr, respectively, are 0.
26, 0. 14, and 0. 14; those hosts with 3 satellites >= Sgr (as the MW) are
among the most common cases, though the most and 2nd most massive satellites in
these systems are SMALLER than the LMC and SMC by 0.7 and 0.8 dex,
respectively. The cumulative satellite mass function is quite broad, the
particular configuration of the MW being of low frequency but NOT an outlier
(it is within the upper 1sig yet). For the MW satellite configuration, we
constrain the halo mass to be Mh>1.4E12 Msun (1sig level). We find that the
abundance of massive subhalos should agree with the abundance of massive
satellites in all MW-sized hosts (there is not a massive satellite missing
problem for LCDM). However, the vmax of the subhalos of satellites with ms<1E8
Msun is systematically larger than the vmax inferred from current observational
studies of the MW bright dwarfs; at difference of previous works, this
conclusion is based on an analysis of the overall population of MW-sized
galaxies. Some pieces of evidence suggest that the issue could refer only to
satellite dwarfs but not to central dwarfs; then, environmental processes
associated to dwarfs inside host halos combined with SN-driven core expansion
could be at the basis of the lowering of vmax.[Abridged]


title:
A Framework for Characterizing the Atmospheres of Low-Mass Low-Density
  Transiting Planets

abstract:
  We perform modeling investigations to aid in understanding the atmospheres
and composition of small planets of ~2-4 Earth radii, which are now known to be
common in our galaxy. GJ 1214b is a well studied example whose atmospheric
transmission spectrum has been observed by many investigators. Here we take a
step back from GJ 1214b to investigate the role that planetary mass,
composition, and temperature play in impacting the transmission spectra of
these low-mass low-density (LMLD) planets. Under the assumption that these
planets accrete modest hydrogen-dominated atmospheres and planetesimals, we use
population synthesis models to show that predicted metal enrichments of the
H/He envelope are high, with metal mass fraction Z_env values commonly 0.6 to
0.9, or ~100 to 400+ times solar. The high mean molecular weight of such
atmospheres (\mu ~ 5-12) would naturally help to flatten the transmission
spectrum of most LMLD planets. The high metal abundance would also provide
significant condensible material for cloud formation. It is known that the H/He
abundance in Uranus and Neptune decreases with depth, and we show that
atmospheric evaporation of LMLD planets could expose atmospheric layers with
gradually higher Z_env. However, values of Z_env close to solar composition can
also arise, so diversity should be expected. Photochemically produced hazes,
potentially due to methane photolysis, are another possibility for obscuring
transmission spectra. Such hazes may not form above T_eq of ~800-1100 K, which
is testable if such warm, otherwise low mean molecular weight atmospheres are
stable against atmospheric evaporation. We find that available transmission
data are consistent with relatively high mean molecular weight atmospheres for
GJ 1214b and "warm Neptune" GJ 436b. We examine future prospects for
characterizing GJ 1214b with Hubble and the James Webb Space Telescope.


title:
Constraining sub-Parsec Binary Supermassive Black Holes in Quasars with
  Multi-Epoch Spectroscopy. I. The General Quasar Population

abstract:
  We perform a systematic search for sub-parsec binary supermassive black holes
(BHs) in normal broad line quasars at z<0.8, using multi-epoch SDSS
spectroscopy of the broad Hbeta line. Our working model is that: only one of
the two BHs in the binary is active, and dynamically dominates its own broad
line region (BLR); the inactive companion BH is orbiting at a distance of a few
R_BLR, where R_BLR~0.01-0.1 pc is the BLR size. We search for the expected
line-of-sight acceleration of the broad line velocity from binary orbital
motion by cross-correlating SDSS spectra from two epochs separated by up to
several years in the quasar restframe. Out of ~700 pairs of spectra for which
we have good measurements of the velocity shift between two epochs (1-sigma
error~40 km/s), we detect 28 systems with significant velocity shifts in broad
Hbeta, among which seven are the best candidates for the hypothesized binaries.
We use the distribution of the observed accelerations (mostly non-detections)
to place constraints on the abundance of such binary systems among the general
quasar population. Excess variance in the velocity shift is inferred for
observations separated by longer than 0.4 yr (quasar restframe). Attributing
all the excess to binary motion would imply that most of the quasars in this
sample must be in binaries; that the inactive BH must be on average more
massive than the active one; and that the binary separation is at most a few
times the size of the BLR. However, if this excess variance is partly or
largely due to long-term broad line variability, the requirement of a large
population of close binaries is much weakened or even disfavored for massive
companions. [Abridged]