title: Replica symmetry breaking in the Bose glass

abstract:
  We investigate the nature of the Bose glass phase of the disordered
Bose-Hubbard model in $d>2$ and demonstrate the existence of a glass-like
replica symmetry breaking (RSB) order parameter in terms of particle number
fluctuations. Starting from a strong-coupling expansion around the atomic
limit, we study the instability of the Mott insulator towards the formation of
a Bose glass. We add some infinitesimal RSB, following the Parisi hierarchical
approach in the most general form, and observe its flow under the
momentum-shell renormalization group scheme. We find a new fixed point with
one-step RSB, corresponding to the transition between the Mott insulator and a
Bose glass phase with hitherto unseen RSB. The susceptibility associated to
infinitesimal RSB perturbation in the Mott insulator is found to diverge at the
transition with an exponent of $\gamma=1/d$. Our findings are consistent with
the expectation of glassy behavior and the established breakdown of
self-averaging. We discuss the possibility of measuring the glass-like order
parameter in optical lattice experiments as well as in certain spin systems
that are in the same universality class as the Bose-Hubbard model.


title: Grid Topology Identification using Electricity Prices

abstract:
  The potential of recovering the topology of a grid using solely publicly
available market data is explored here. In contemporary whole-sale electricity
markets, real-time prices are typically determined by solving the
network-constrained economic dispatch problem. Under a linear DC model,
locational marginal prices (LMPs) correspond to the Lagrange multipliers of the
linear program involved. The interesting observation here is that the matrix of
spatiotemporally varying LMPs exhibits the following property: Once
premultiplied by the weighted grid Laplacian, it yields a low-rank and sparse
matrix. Leveraging this rich structure, a regularized maximum likelihood
estimator (MLE) is developed to recover the grid Laplacian from the LMPs. The
convex optimization problem formulated includes low rank- and
sparsity-promoting regularizers, and it is solved using a scalable algorithm.
Numerical tests on prices generated for the IEEE 14-bus benchmark provide
encouraging topology recovery results.


title:
Radiative corrections to the charged pion-pair production process
  {\boldmath$\pi^-\gamma\to \pi^+\pi^-\pi^-$} at low energies

abstract:
  We calculate the one-photon loop radiative corrections to the charged
pion-pair production process $\pi^-\gamma\to\pi^+\pi^-\pi^-$. In the low-energy
region this reaction is governed by the chiral pion-pion interaction. The
pertinent set of 42 irreducible photon-loop diagrams is calculated by using the
package FeynCalc. Electromagnetic counterterms with two independent low-energy
constants $\widehat k_1$ and $\widehat k_2$ are included in order to remove the
ultraviolet divergences generated by the photon-loops. Infrared finiteness of
the virtual radiative corrections is achieved by including soft photon
radiation below an energy cut-off $\lambda$. The purely electromagnetic
interaction of the charged pions mediated by one-photon exchange is also taken
into account. The radiative corrections to the total cross section (in the
isospin limit) vary between $+10\%$ close to threshold and about $-1\%$ at a
center-of-mass energy of $7m_\pi$. The largest contribution comes from the
simple one-photon exchange. Radiative corrections to the $\pi^+\pi^-$ and
$\pi^-\pi^-$ mass spectra are studied as well. The Coulomb singularity of the
final-state interaction produces a kink in the dipion mass spectra. The virtual
radiative corrections to elastic $\pi^-\pi^-$ scattering are derived
additionally.


title: Families of Parsimonious Finite Mixtures of Regression Models

abstract:
  Finite mixtures of regression models offer a flexible framework for
investigating heterogeneity in data with functional dependencies. These models
can be conveniently used for unsupervised learning on data with clear
regression relationships. We extend such models by imposing an
eigen-decomposition on the multivariate error covariance matrix. By
constraining parts of this decomposition, we obtain families of parsimonious
mixtures of regressions and mixtures of regressions with concomitant variables.
These families of models account for correlations between multiple responses.
An expectation-maximization algorithm is presented for parameter estimation and
performance is illustrated on simulated and real data.


title:
Fluctuation exponents for directed polymers in the intermediate disorder
  regime

abstract:
  We compute the fluctuation exponents for a solvable model of one-dimensional
directed polymers in random environment in the intermediate regime. This regime
corresponds to taking the inverse temperature to zero with the size of the
system. The exponents satisfy the KPZ scaling relation and coincide with
physical predictions. In the critical case, we recover the fluctuation
exponents of the Cole-Hopf solution of the KPZ equation in equilibrium and
close to equilibrium.


title:
Theoretical Foundation for Research in Communication using Information
  and Communication Technology Devices in Healthcare: An Interdisciplinary
  Scoping Review

abstract:
  Faulty communication between team members is one of the most important
factors preventing substantial improvement in patient safety. Aviation, nuclear
power and defense have been able to improve their safety record by adopting
theory and model based solutions. In contrast, healthcare's thrust towards
modern communication devices is largely devoid of theoretical foundation. The
objective of this scoping review is to compile communication theories,
frameworks, and models used by high risk organizations outside healthcare to
study and resolve workplace communication issues. The healthcare databases
searched included Medline, CINAHL, EMBASE, and PsycInfo. In addition, we
searched engineering and science literature to include articles in the fields
of information sciences, computer sciences, nuclear power generation, aviation,
the military and other domains such as sociology that address the science and
theory of communication. Comprehensive searching was also done in the
communication studies literature. We also reviewed conference proceedings and
grey literature and conducted citation tracking. Our initial systematic search
yielded 15,365 articles. Hand searching and reviewing references resulted in a
set of 181 articles. 144 full text articles were read and 40 of them were
selected to be included in the review. We were able to identify 14 theories and
12 models which could be applied in hospital communication research. However,
it must be noted that most of them have not yet been applied in biomedical
research in hospital communication and as such their applicability can only be
suggested-a gap which future research may be able to address. Formulation of a
custom model representing the unique features and complexities of communication
within hospitals is recommended.


title:
Quantitative studies of the homogeneous Bethe-Salpeter Equation in
  Minkowski space

abstract:
  The Bethe-Salpeter Equation for a bound system, composed by two massive
scalars exchanging a massive scalar, is quantitatively investigated in ladder
approximation, within the Nakanishi integral representation approach. For the
S-wave case, numerical solutions with a form inspired by the Nakanishi integral
representation, have been calculated. The needed Nakanishi weight functions
have been evaluated by solving two different eigenequations, obtained directly
from the Bethe-Salpeter equation applying the Light-Front projection technique.
A remarkable agreement, in particular for the eigenvalues, has been achieved,
numerically confirming that the Nakanishi uniqueness theorem for the weight
functions, demonstrated in the context of the perturbative analysis of the
multi-leg transition amplitudes and playing a basic role in suggesting one of
the two adopted eigenequations, can be extended to a non perturbative realm.
The detailed, quantitative studies are completed by presenting both
probabilities and Light-Front momentum distributions for the valence component
of the bound state.

categories: hep-ph cond-mat.mes-hall cond-mat.str-el nucl-th


title:
Analog Baseband Cancellation for Full-Duplex: An Experiment Driven
  Analysis

abstract:
  Recent wireless testbed implementations have proven that full-duplex
communication is in fact possible and can outperform half-duplex systems. Many
of these implementations modify existing half-duplex systems to operate in
full-duplex. To realize the full potential of full-duplex, radios need to be
designed with self-interference in mind. In our work, we use a novel patch
antenna prototype in an experimental setup to characterize the
self-interference channel between transmit and receive radios. We derive an
equivalent analytical baseband model and propose analog baseband cancellation
techniques to complement the RF cancellation provided by the patch antenna
prototype. Our results show that a wide bandwidth, moderate isolation scheme
achieves up to 2.4 bps/Hz higher achievable rate than a narrow bandwidth, high
isolation scheme. Furthermore, the analog baseband cancellation yields a
10-10,000 improvement in BER over RF only cancellation.


title: Plasmas generated by ultra-violet light rather than electron impact

abstract:
  We analyze, in both plane and cylindrical geometries, a collisionless plasma
consisting of an inner region where generation occurs by UV illumination, and
an un-illuminated outer region with no generation. Ions generated in the inner
region flow outwards through the outer region and into a wall. We solve for
this system's steady state, first in the quasi-neutral regime (where the Debye
length ${\lambda}_D$ vanishes and analytic solutions exist) and then in the
general case, which we solve numerically. In the general case a double layer
forms where the illuminated and un-illuminated regions meet, and an
approximately quasi-neutral plasma connects the double layer to the wall
sheath; in plane geometry the ions coast through the quasi-neutral section at
slightly more than the Bohm speed $c_s$. The system, although simple, therefore
has two novel features: a double layer that does not require counter-streaming
ions and electrons, and a quasi-neutral plasma where ions travel in straight
lines with at least the Bohm speed. We close with a pr\'{e}cis of our
asymptotic solutions of this system, and suggest how our theoretical
conclusions might be extended and tested in the laboratory.


title: Coherent excitation-selective spectroscopy in planar metamaterials

abstract:
  In a proof-of-principle experiment with metamaterials exhibiting electric
dipolar and magnetic dipolar resonances, we demonstrated that the electric and
magnetic resonances can be separately switches off and on by positioning the
metamaterials along a standing wave, while both resonances are present in
travelling-wave spectra.


title:
Near Optimal Compressed Sensing of a Class of Sparse Low-Rank Matrices
  via Sparse Power Factorization

abstract:
  Compressed sensing of simultaneously sparse and low-rank matrices enables
recovery of sparse signals from a few linear measurements of their bilinear
form. One important question is how many measurements are needed for a stable
reconstruction in the presence of measurement noise. Unlike conventional
compressed sensing for sparse vectors, where convex relaxation via the
$\ell_1$-norm achieves near optimal performance, for compressed sensing of
sparse low-rank matrices, it has been shown recently Oymak et al. that convex
programmings using the nuclear norm and the mixed norm are highly suboptimal
even in the noise-free scenario.
  We propose an alternating minimization algorithm called sparse power
factorization (SPF) for compressed sensing of sparse rank-one matrices. For a
class of signals whose sparse representation coefficients are fast-decaying,
SPF achieves stable recovery of the rank-1 matrix formed by their outer product
and requires number of measurements within a logarithmic factor of the
information-theoretic fundamental limit. For the recovery of general sparse
low-rank matrices, we propose subspace-concatenated SPF (SCSPF), which has
analogous near optimal performance guarantees to SPF in the rank-1 case.
Numerical results show that SPF and SCSPF empirically outperform convex
programmings using the best known combinations of mixed norm and nuclear norm.


title: Cache-Oblivious Peeling of Random Hypergraphs

abstract:
  The computation of a peeling order in a randomly generated hypergraph is the
most time-consuming step in a number of constructions, such as perfect hashing
schemes, random $r$-SAT solvers, error-correcting codes, and approximate set
encodings. While there exists a straightforward linear time algorithm, its poor
I/O performance makes it impractical for hypergraphs whose size exceeds the
available internal memory.
  We show how to reduce the computation of a peeling order to a small number of
sequential scans and sorts, and analyze its I/O complexity in the
cache-oblivious model. The resulting algorithm requires $O(\mathrm{sort}(n))$
I/Os and $O(n \log n)$ time to peel a random hypergraph with $n$ edges.
  We experimentally evaluate the performance of our implementation of this
algorithm in a real-world scenario by using the construction of minimal perfect
hash functions (MPHF) as our test case: our algorithm builds a MPHF of $7.6$
billion keys in less than $21$ hours on a single machine. The resulting data
structure is both more space-efficient and faster than that obtained with the
current state-of-the-art MPHF construction for large-scale key sets.


title: Massive fermions in 2+1 dimensions

abstract:
  We construct the higher-spin massive fermionic fields in 2+1 dimensions.
Their field equations and propagators are derived from first principle. For
fields with j>1/2, complications arise from the non-linear behaviour of the
boost operators. We find that for a spin-three-half field, the non-linearity
have an underlying structure that guarantees the locality of the fields and the
existence of covariant propagators. We conjecture that this structure exists
for fields of all spin.


title:
Linear Response Theory for Shear Modulus $C_{66}$ and Raman Quadrupole
  Susceptibility: Significant Evidence for Orbital Nematic Fluctuations in
  Fe-Based Superconductors

abstract:
  The emergence of the nematic order and fluctuations has been discussed as a
central issue in Fe-based superconductors. To clarify the origin of the
nematicity, we focus on the shear modulus $C_{66}$ and the Raman quadrupole
susceptibility $\chi_{x^2-y^2}^{Raman}$. Due to the Aslamazov-Larkin vertex
correction, the nematic-type orbital fluctuations are induced, and they
enhances both $1/C_{66}$ and $\chi_{x^2-y^2}^{Raman}$ strongly. However,
$\chi_{x^2-y^2}^{Raman}$ remains finite even at the structure transition
temperature $T_S$, because of the absence of the band Jahn-Teller effect and
the Pauli (=intra-band) contribution, as proved in terms of the linear response
theory. The present study clarifies that origin of the nematicity in Fe-based
superconductors is the nematic-orbital order/fluctuations.


title:
Effects of strain on the valence band structure and exciton-polariton
  energies in ZnO

abstract:
  The uniaxial stress dependence of the band structure and the
exciton-polariton transitions in wurtzite ZnO is thoroughly studied using
modern first-principles calculations based on the HSE+G0W0 approach, k p
modeling using the deformation potential framework, and polarized
photoluminescence measurements. The ordering of the valence bands [A(G7),
B(G9), C(G7)] is found to be robust even for high uniaxial and biaxial strains.
Theoretical results for the uniaxial pressure coefficients and splitting rates
of the A, B, and C valence bands and their optical transitions are obtained
including the effects of the spin-orbit interaction. The excitonic deformation
potentials are derived and the stress rates for hydrostatic pressure are
determined based on the results for uniaxial and biaxial stress. In addition,
the theory for the stress dependence of the exchange interaction and
longitudinal-transversal splitting of the exciton-polaritons is developed using
the basic exciton functions of the quasi-cubic approximation and taking the
interaction between all exciton states into account. It is shown that the
consideration of these effects is crucial for an accurate description of the
stress dependence of the optical spectra in ZnO. The theoretical results are
compared to polarized photoluminescence measurements of different ZnO
substrates as function of uniaxial pressure and experimental values reported in
the literature demonstrating an excellent agreement with the computed pressure
coefficients.


title:
A new model for NVSS galaxy catalogue using the redshift distribution
  and halo minimum mass

abstract:
  In the present paper we study the radio sources in the NRAO VLA SKY Survey
(NVSS) analysing its power spectrum and galaxy distribution. There is a
discrepancy between the theoretical models in the literature and the data at
large scales. A new model for NVSS is proposed combining the power spectrum
data from NVSS and the galaxy distribution from the Combined EIS-NVSS Survey Of
Radio Sources (CENSORS). Taken into account these two data sets the differences
in the power spectrum at large scales are reduced, but there is still some
tension between the two data sets. Different models are compared using Bayesian
evidence. A model for the galaxy distribution based on a gamma function
provides a higher evidence against other models proposed in the literature. In
addition, the effect of primordial non-Gaussianity has been also considered.
The 2-sigma constraints on the local non-Gaussian f_NL parameter are -43 < f_NL
< 142.


title: Optimal A Priori Balance in the Design of Controlled Experiments

abstract:
  We develop a unified theory of designs for controlled experiments that
balance baseline covariates a priori (before treatment and before
randomization) using the framework of minimax variance and a new method called
kernel allocation. We show that any notion of a priori balance must go hand in
hand with a notion of structure, since with no structure on the dependence of
outcomes on baseline covariates complete randomization (no special covariate
balance) is always minimax optimal. Restricting the structure of dependence,
either parametrically or non-parametrically, gives rise to certain covariate
imbalance metrics and optimal designs. This recovers many popular imbalance
metrics and designs previously developed ad hoc, including randomized block
designs, pairwise-matched allocation and rerandomization. We develop a new
design method called kernel allocation based on the optimal design when
structure is expressed by using kernels, which can be parametric or
non-parametric. Relying on modern optimization methods, kernel allocation,
which ensures nearly perfect covariate balance without biasing estimates under
model misspecification, offers sizable advantages in precision and power as
demonstrated in a range of real and synthetic examples. We provide strong
theoretical guarantees on variance, consistency and rates of convergence and
develop special algorithms for design and hypothesis testing.


title:
Representations of the ultrahyperbolic BMS group HB.II. Determination of
  the representations induced from infinite little groups

abstract:
  The ordinary Bondi-Metzner-Sachs (BMS) group B is the common asymptotic
symmetry group of all asymptotically flat Lorentzian space-times. As such, B is
the best candidate for the universal symmetry group of General Relativity.
However, in studying quantum gravity, space-times with signatures other than
the usual Lorentzian one, and complex space-times, are frequently considered.
Generalisations of B appropriate to these other signatures have been defined
earlier. In particular, the generalisation HB, a BMS group appropriate to the
ultrahyperbolic signature (+,+,-,-), has been defined in a previous paper where
it was shown that all the strongly continuous unitary irreducible
representations (IRs) of HB can be obtained with the Wigner-Mackey's inducing
method and that all the little groups of HB are compact. Here we describe in
detail all the infinite little groups of HB and we find the IRs of HB induced
by them.


title: Convergence of Ising interfaces to Schramm's SLE curves

abstract:
  We show how to combine our earlier results to deduce strong convergence of
the interfaces in the planar critical Ising model and its random-cluster
representation to Schramm's SLE curves with parameter $\kappa=3$ and
$\kappa=16/3$ respectively.


title:
The method of cyclic intrepid projections: convergence analysis and
  numerical experiments

abstract:
  The convex feasibility problem asks to find a point in the intersection of a
collection of nonempty closed convex sets. This problem is of basic importance
in mathematics and the physical sciences, and projection (or splitting) methods
solve it by employing the projection operators associated with the individual
sets to generate a sequence which converges to a solution. Motivated by an
application in road design, we present the method of cyclic intrepid
projections (CycIP) and provide a rigorous convergence analysis. We also report
on very promising numerical experiments in which CycIP is compared to a
commercial state-of-the-art optimization solver.


title:
Non-CMC solutions of the Einstein constraint equations on asymptotically
  Euclidean manifolds

abstract:
  In this note we prove two existence theorems for the Einstein constraint
equations on asymptotically Euclidean manifolds. The first is for arbitrary
mean curvature functions with restrictions on the size of the
transverse-traceless data and the non-gravitational field data, while the
second assumes a near-CMC condition, with no other restrictions.


title:
Casimir-like corrections to the classical tensions of the strings and
  membranes

abstract:
  We find the Casimir-like energies for strings and membranes. We show that the
related Casimir forces can be interpreted as quantum corrections to the
classical tensions of the strings and membranes. We see that these corrections
always increase the tensions of the circular string as well as spherical
membrane, while for the straight string, rectangular and cylindrical membranes,
these Casimir forces may increase or decrease the tensions. So we find that the
quantum vacuum can break the (tensional) isotropy of the rectangular and
cylindrical membranes. Also obtaining the nonzero-temperature Casimir energy,
we find relations for the tensions at nonzero temperature.


title:
Tidal End States of Binary Asteroid Systems with a Nonspherical
  Component

abstract:
  We derive the locations of the fully synchronous end states of tidal
evolution for binary asteroid systems having one spherical component and one
oblate- or prolate-spheroid component. Departures from a spherical shape, at
levels observed among binary asteroids, can result in the lack of a stable
tidal end state for particular combinations of the system mass fraction and
angular momentum, in which case the binary must collapse to contact. We
illustrate our analytical results with near-Earth asteroids (8567) 1996 HW1,
(66391) 1999 KW4, and 69230 Hermes.


title: Nonparametric estimation of the dynamic range of music signals

abstract:
  The dynamic range is an important parameter which measures the spread of
sound power, and for music signals it is a measure of recording quality. There
are various descriptive measures of sound power, none of which has strong
statistical foundations. We start from a nonparametric model for sound waves
where an additive stochastic term has the role to catch transient energy. This
component is recovered by a simple rate-optimal kernel estimator that requires
a single data-driven tuning. The distribution of its variance is approximated
by a consistent random subsampling method that is able to cope with the massive
size of the typical dataset. Based on the latter, we propose a statistic, and
an estimation method that is able to represent the dynamic range concept
consistently. The behavior of the statistic is assessed based on a large
numerical experiment where we simulate dynamic compression on a selection of
real music signals. Application of the method to real data also shows how the
proposed method can predict subjective experts' opinions about the hifi quality
of a recording.


title: Loss systems in a random environment

abstract:
  We consider a single server system with infinite waiting room in a random
environment. The service system and the environment interact in both
directions. Whenever the environment enters a prespecified subset of its state
space the service process is completely blocked: Service is interrupted and
newly arriving customers are lost. We prove an if-and-only-if-condition for a
product form steady state distribution of the joint queueing-environment
process. A consequence is a strong insensitivity property for such systems.
  We discuss several applications, e.g. from inventory theory and reliability
theory, and show that our result extends and generalizes several theorems found
in the literature, e.g. of queueing-inventory processes.
  We investigate further classical loss systems, where due to finite waiting
room loss of customers occurs. In connection with loss of customers due to
blocking by the environment and service interruptions new phenomena arise.
  We further investigate the embedded Markov chains at departure epochs and
show that the behaviour of the embedded Markov chain is often considerably
different from that of the continuous time Markov process. This is different
from the behaviour of the standard M/G/1, where the steady state of the
embedded Markov chain and the continuous time process coincide.
  For exponential queueing systems we show that there is a product form
equilibrium of the embedded Markov chain under rather general conditions. For
systems with non-exponential service times more restrictive constraints are
needed, which we prove by a counter example where the environment represents an
inventory attached to an M/D/1 queue. Such integrated queueing-inventory
systems are dealt with in the literature previously, and are revisited here in
detail.


title: Closed three-dimensional Alexandrov spaces with isometric circle actions

abstract:
  We obtain a topological and weakly equivariant classification of closed
three-dimensional Alexandrov spaces with an effective isometric circle action.
As an application of the classification we prove a version of the Borel
conjecture for closed three-dimensional Alexandrov spaces with circle symmetry.


title: Linear Spinor Fields in Relativistic Dynamics

abstract:
  Linear spinor fields are a generalization of the Dirac field that have
transparent cluster decomposability properties needed for classical
correspondence of relativistic quantum systems. The algebra of these fields
directly incorporate gravitation within a group that unifies the dynamics of
the same number of additional hermitian carriers of quantum numbers as there
are gauge fields in SU(3)$\times$SU(2)$\times$U(1). They also provide a
mechanism for the dynamic mixing of massless neutrinos using a "transverse
mass" conjugate to the affine parameter labeling translations along its
light-like trajectory, consistent with those in the standard model.


title: Combinatorial species and graph enumeration

abstract:
  In enumerative combinatorics, it is often a goal to enumerate both labeled
and unlabeled structures of a given type. The theory of combinatorial species
is a novel toolset which provides a rigorous foundation for dealing with the
distinction between labeled and unlabeled structures. The cycle index series of
a species encodes the labeled and unlabeled enumerative data of that species.
Moreover, by using species operations, we are able to solve for the cycle index
series of one species in terms of other, known cycle indices of other species.
Section 3 is an exposition of species theory and Section 4 is an enumeration of
point-determining bipartite graphs using this toolset. In Section 5, we extend
a result about point-determining graphs to a similar result for
point-determining {\Phi}-graphs, where {\Phi} is a class of graphs with certain
properties. Finally, Appendix A is an expository on species computation using
the software Sage [9] and Appendix B uses Sage to calculate the cycle index
series of point-determining bipartite graphs.


title: A remark on the Cox ring of $\overline{M}_{0,n}$

abstract:
  We present an elementary inductive argument proving that a certain subring of
the Cox ring of the moduli space $\overline{M}_{0,n}$ of stable rational curves
with $n$ marked points is finitely generated for every $n \ge 3$.


title:
Nodeless superconducting gap induced by odd parity pair density wave in
  underdoped cuprates

abstract:
  We present a theoretical model to show that the transition from an
antiferromagnetic (AFM) phase to the $d_{x^2-y^2}$-wave superconductivity
occurs through a robust companion of a finite momentum pairing between $({\bf
k},\uparrow)$ and $(-{\bf k}-{\bf Q},\downarrow)$ electrons, namely
pair-density wave (PDW) state, where ${\bf Q}=(\pi,\pi)$ is the AFM wavevector.
Interestingly, the spatial structure of the PDW is constrained to be a
$p+ip$-wave symmetry, which follows $p_{\bf k}=p_{-{\bf k}-{\bf Q}}$ under
fermions exchange in cuprates, dictating a spin-singlet pairing. Furthermore,
the PDW state produces a fully gapped quasiparticle spectrum which explains
recent observations of the fully gapped quasiparticle structure of lightly
doped cuprates in the hole doping side. We study the stability of all three
phases within the self-consistent mean-field theory. Finally, we calculate the
superfluid density to propose its exponential temperature dependence as a test
to the SC origin of this fully gapped state, while the phase modulation of the
PDW state can be visualized by scanning probes.


title:
Pixelated Geiger-Mode Avalanche Photo-Diode Characterization through
  Dark Current Measurement

abstract:
  PIXELATED geiger-mode avalanche photodiodes(PPDs), often called silicon
photomultipliers (SiPMs) are emerging as an excellent replacement for
traditional photomultiplier tubes (PMTs) in a variety of detectors, especially
those for subatomic physics experiments, which requires extensive test and
operation procedures in order to achieve uniform responses from all the
devices. In this paper, we show for two PPD brands, Hamamatsu MPPC and SensL
SPM, that the dark noise rate, breakdown voltage and rate of correlated
avalanches can be inferred from the sole measure of dark current as a function
of operating voltage, hence greatly simplifying the characterization procedure.
We introduce a custom electronics system that allows measurement for many
devices concurrently, hence allowing rapid testing and monitoring of many
devices at low cost. Finally, we show that the dark current of Hamamastu
Multi-Pixel Photon Counter (MPPC) is rather independent of temperature at
constant operating voltage, hence the current measure cannot be used to probe
temperature variations. On the other hand, the MPPC current can be used to
monitor light source conditions in DC mode without requiring strong temperature
stability, as long as the integrated source brightness is comparable to the
dark noise rate.


title: A unified NLO description of top-pair and associated Wt production

abstract:
  We present an NLO simulation of WWbb production with massive b-quarks at the
LHC. Off-shell and non-resonant contributions associated with top-pair and
single-top channels and with leptonic W-boson decays are consistently taken
into account using the complex-mass scheme. Thanks to the finite b-quark mass,
WWbb predictions can be extended to the whole b-quark phase space, thereby
including Wt-channel single-top contributions that originate from collinear
g->bb splittings in the four-flavour scheme. This provides a consistent NLO
description of tt and Wt production and decay, including quantum interference
effects. The simulation is also applicable to exclusive 0- and 1-jet bins,
which is of great importance for Higgs-boson studies in the H->WW channel and
for any other analysis with large top backgrounds and jet vetoes or jet bins.


title: Capture and isolation of highly-charged ions in a unitary Penning trap

abstract:
  We recently used a compact Penning trap to capture and isolate highly-charged
ions extracted from an electron beam ion trap (EBIT) at the National Institute
of Standards and Technology (NIST). Isolated charge states of highly-stripped
argon and neon ions with total charge $Q \geq 10$, extracted at energies of up
to $4\times 10^3\,Q$ eV, are captured in a trap with well depths of $\,\approx
(4\, {\rm to}\, 12)\,Q$ eV. Here we discuss in detail the process to optimize
velocity-tuning, capture, and storage of highly-charged ions in a unitary
Penning trap designed to provide easy radial access for atomic or laser beams
in charge exchange or spectroscopic experiments, such as those of interest for
proposed studies of one-electron ions in Rydberg states or optical transitions
of metastable states in multiply-charged ions. Under near-optimal conditions,
ions captured and isolated in such rare-earth Penning traps can be
characterized by an initial energy distribution that is $\approx$ 60 times
narrower than typically found in an EBIT. This reduction in thermal energy is
obtained passively, without the application of any active cooling scheme in the
ion-capture trap.


title:
Eight types of physical "arrows" distinguished by Newtonian space-time
  symmetry

abstract:
  The paper draws the attention to the spatiotemporal symmetry of various
vector-like physical quantities. The symmetry is specified by their invariance
under the action of symmetry operations of the Opechowski nonrelativistic
space-time rotation group O(3).{1, 1'}= O'(3), where 1' is time-reversal
operation. It is argued that along with the canonical polar vector, there are
another 7 symmetrically distinct classes of stationary physical quantities,
which can be - and often are - denoted as standard three-components vectors,
even though they do not transform as a static polar vector under all operations
of O'(3). The octet of symmetrically distinct "directional quantities" can be
exemplified by: two kinds of polar vectors (electric dipole moment P and
magnetic toroidal moment T, two kinds of axial vectors (magnetization M and
electric toroidal moment G), two kinds of chiral "bi-directors" C and F
(associated with the so-called true and false chirality, resp.) and still
another two achiral "bi-directors" N and L, transforming as the nematic liquid
crystal order parameter and as the antiferromagnetic order parameter of the
hematite crystal alpha-Fe2O3, respectively.


title:
Multi-leptons and Top-jets in the Hunt for Gluinos in R-parity Violating
  Supersymmetry

abstract:
  The presence of R-parity ($\mathcal{R}_p$) violation offers intersting decay
channels for the gluinos. In this work we present a new search strategy for the
gluinos in the presence of semileptonic $\mathcal{R}_p$ violating couplings
$\lambda^{'}_{133}$ and $\lambda^{'}_{233}$. We consider two scenarios (i)
$\lambda^{'}$ induced 3-body decay of gluinos to a top quark ($t$), a bottom
quark ($b$) and a light lepton ($\ell$) (ii) cascade decay of gluinos to top
quarks and neutralinos ($\widetilde{\chi}_1^0$) followed by the decay of
$\widetilde{\chi}_1^0$ to $t$, $b$ and $\ell$ through $\lambda^{'}$ couplings.
We present two different search procedures which are common to both the
scenarios. While the first one involves the traditional approach with
multi-leptons and $b$-tagged jets, the second one employs the more recent
technique to reconstruct highly energetic hadronically decaying top quarks. We
perform a detailed simulation of the signal as well as all the relevant
Standard Model backgrounds to show that the second procedure offers slightly
better sensitivity for gluino discovery. In both the procedures, a $\geq$
5$\sigma$ discovery is possible for the gluino mass in the range 1.5 -1.7 TeV
at 14 TeV LHC with 50 fb$^{-1}$ integrated luminosity.


title:
A Diagrammatic Kinetic Theory of Density Fluctuations in Simple Liquids
  in the Overdamped Limit. II. The One-Loop Approximation

abstract:
  A diagrammatic kinetic theory of density fluctuations in simple dense liquids
at long times, described in the preceding paper, is applied to a high density
Lennard-Jones liquid to calculate various equilibrium time correlation
functions. The calculation starts from the general theory and makes two
approximations. 1. The general diagrammatic expression for an irreducible
memory kernel is approximated using a one-loop approximation. 2. The
generalized Enskog projected propagator, which is required for the calculation,
is approximated using a simple kinetic model for the hard sphere memory
function. The coherent intermediate scattering function (CISF), the
longitudinal current correlation function (LCCF), the transverse current
correlation function (TCCF), the incoherent intermediate scattering function
(IISF), and the incoherent longitudinal current correlation function (ILCCF)
are calculated and compared with simulation results for the Lennard-Jones
liquid at high density. The approximate theoretical results are in good
agreement with the simulation data for the IISF for all wave vectors studied
and for the CISF and LCCF for large wave vector. The approximate results are in
poor agreement with the simulation data for the CISF, LCCF, and TCCF for small
wave vectors because these functions are strongly affected by hydrodynamic
fluctuations at small wave vector that are not well described by the simple
kinetic model used. The possible implications of this approach for the study of
liquids is discussed.


title: A Heyting Algebra on Dyck Paths of Type $A$ and $B$

abstract:
  In this article we investigate the lattices of Dyck paths of type $A$ and $B$
under dominance order, and explicitly describe their Heyting algebra structure.
This means that each Dyck path of either type has a relative pseudocomplement
with respect to some other Dyck path of the same type. While the proof that
this lattice forms a Heyting algebra is quite straightforward, the explicit
computation of the relative pseudocomplements using the lattice-theoretic
definition is quite tedious. We give a combinatorial description of the Heyting
algebra operations join, meet, and relative pseudocomplement in terms of height
sequences, and we use these results to derive formulas for pseudocomplements
and to characterize the regular elements in these lattices.


title: HerMES: Point source catalogues from Herschel-SPIRE observations II

abstract:
  The Herschel Multi-tiered Extragalactic Survey (HerMES) is the largest
Guaranteed Time Key Programme on the Herschel Space Observatory. With a wedding
cake survey strategy, it consists of nested fields with varying depth and area
totalling ~380 deg^2. In this paper, we present deep point source catalogues
extracted from Herschel-SPIRE observations of all HerMES fields, except for the
later addition of the 270 deg^2 HeLMS field. These catalogues constitute the
second Data Release (DR2) made in October 2013. A subset of these catalogues,
which consists of bright sources extracted from Herschel-SPIRE observations
completed by May 1, 2010 (covering ~ 74 deg^2) were released earlier in the
first extensive Data Release (DR1) in March 2012. Two different methods are
used to generate the point source catalogues, the SUSSEXtractor (SXT) point
source extractor used in two earlier data releases (EDR and EDR2) and a new
source detection and photometry method. The latter combines an iterative source
detection algorithm, StarFinder (SF), and a De-blended SPIRE Photometry
(DESPHOT) algorithm. We use end-to-end Herschel-SPIRE simulations with
realistic number counts and clustering properties to characterise basic
properties of the point source catalogues, such as the completeness,
reliability, photometric and positional accuracy. Over 500, 000 catalogue
entries in HerMES fields (except HeLMS) are released to the public through the
HeDAM website (http://hedam.oamp.fr/herMES).


title:
Shifted convolution sums and Burgess type subconvexity over number
  fields

abstract:
  Let $F$ be a number field and $\pi$ an irreducible cuspidal representation of
$\mathrm{GL}_{2}(F)\backslash\mathrm{GL}_{2}(\mathbf{A})$ with unitary central
character. Then the bound
$$L(1/2,\pi\otimes\chi)\ll_{F,\pi,\chi_{\infty},\varepsilon}
\mathcal{N}(\frak{q})^{3/8+\theta/4+\varepsilon}$$ holds for any Hecke
character $\chi$ of conductor $\frak{q}$, where $\theta$ is any constant
towards the Ramanujan-Petersson conjecture ($\theta=7/64$ is admissible). The
proof is based on a spectral decomposition of shifted convolution sums.


title:
Exotic properties of neutrinos using effective Lagrangians and specific
  models

abstract:
  This doctoral dissertation presents several works on nonstandard properties
of neutrinos exploiting the synergies between effective field theory and
models. The phenomena are first analysed by means of effective operators, which
allow to discuss their phenomenological consequences and to derive estimations
about the mass scale of the heavy particles needed to induce the new
interactions. In a second phase we propose models that realise the effective
operators, allowing us to check the conclusions of effective field theory as
well as to extract new phenomenological features of the scenarios considered.
The text is divided into two parts: in the first one we apply these ideas to an
effective interaction that generates magnetic dipole moments for right-handed
neutrinos, and in the second one we discuss a family of operators that violate
lepton number without quarks, and which can allow for large rates of
neutrinoless double $\beta$ decay and small neutrino masses. The right-handed
neutrino magnetic moments have the potential to show up in many different
scenarios, and the nonobservation of the associated phenomenology allows to
constrain their value, and therefore the associated new physics scale. The
operators discussed in the second part of the text can potentially dominate
neutrinoless double $\beta$ decay and provide signals in the next generation of
experiments; they can be classified according to the chirality of the two
final-state leptons, and induce neutrino mass matrices with a well-defined
hierarchy related to that of the charged lepton masses. In both cases we
provide example models that realise the phenomenology and we discuss their
observability in ongoing and near-future experiments.


title:
Group theoretic, Lie algebraic and Jordan algebraic formulations of the
  SIC existence problem

abstract:
  Although symmetric informationally complete positive operator valued measures
(SIC POVMs, or SICs for short) have been constructed in every dimension up to
67, a general existence proof remains elusive. The purpose of this paper is to
show that the SIC existence problem is equivalent to three other, on the face
of it quite different problems. Although it is still not clear whether these
reformulations of the problem will make it more tractable, we believe that the
fact that SICs have these connections to other areas of mathematics is of some
intrinsic interest. Specifically, we reformulate the SIC problem in terms of
(1) Lie groups, (2) Lie algebras and (3) Jordan algebras (the second result
being a greatly strengthened version of one previously obtained by Appleby,
Flammia and Fuchs). The connection between these three reformulations is
non-trivial: It is not easy to demonstrate their equivalence directly, without
appealing to their common equivalence to SIC existence. In the course of our
analysis we obtain a number of other results which may be of some independent
interest.


title: Ploidy and the Predictability of Evolution in Fishers Geometric Model

abstract:
  Predicting adaptive evolutionary trajectories is a primary goal of
evolutionary biology. One can differentiate between forward and backward
predictability, where forward predictability measures the likelihood of the
same adaptive trajectory occurring in independent evolutions and backward
predictability measures the likelihood of a particular adaptive path given the
knowledge of starting and final states. Recent studies have attempted to
measure both forward and backward predictability using experimental evolution
in asexual haploid microorganisms. Similar experiments in diploid organisms
have not been conducted. Here we simulate adaptive walks using Fisher's
Geometric Model in haploids and diploids and find that adaptive walks in
diploids are less forward- and more backward-predictable than adaptive walks in
haploids. We argue that the difference is due to the ability of diploids in our
simulations to generate transiently stable polymorphisms and to allow adaptive
mutations of larger phenotypic effect. As stable polymorphisms can be generated
in both haploid and diploid natural populations through a number of mechanisms,
we argue that inferences based on experiments in which adaptive walks proceed
through succession of monomorphic states might miss many of the key features of
adaptation.


title: Asymptotic distribution of the Markowitz portfolio

abstract:
  The asymptotic distribution of the Markowitz portfolio is derived, for the
general case (assuming fourth moments of returns exist), and for the case of
multivariate normal returns. The derivation allows for inference which is
robust to heteroskedasticity and autocorrelation of moments up to order four.
As a side effect, one can estimate the proportion of error in the Markowitz
portfolio due to mis-estimation of the covariance matrix. A likelihood ratio
test is given which generalizes Dempster's Covariance Selection test to allow
inference on linear combinations of the precision matrix and the Markowitz
portfolio. Extensions of the main method to deal with hedged portfolios,
conditional heteroskedasticity, conditional expectation, and constrained
estimation are given. It is shown that the Hotelling-Lawley statistic
generalizes the (squared) Sharpe ratio under the conditional expectation model.
Asymptotic distributions of all four of the common `MGLH' statistics are found,
assuming random covariates. Examples are given demonstrating the possible uses
of these results.


title:
IceCube's Neutrinos: The beginning of extra-Galactic neutrino
  astrophysics?

abstract:
  The flux, spectrum and angular distribution of the excess neutrino signal
detected by IceCube between 50TeV and 2PeV are inconsistent with those expected
for Galactic sources. The coincidence of the excess,
$E_\nu^2\Phi_\nu=3.6\pm1.2\times10^{-8}(GeV/ cm^2 sr s)$, with the
Waxman-Bahcall (WB) bound, $E_\nu^2\Phi_{WB}=3.4\times10^{-8}(GeV/cm^2 sr s)$,
is probably a clue to the origin of IceCube's neutrinos. The most natural
explanation of this coincidence is that both the neutrino excess and the
ultra-high energy, $>10^{19}$ eV, cosmic-ray (UHECR) flux are produced by the
same population of cosmologically distributed sources, producing CRs, likely
protons, at a similar rate, $E^2 dQ/dE=0.5\times10^{44}(erg/Mpc^3yr)$ (at z=0),
across a wide range of energies, from $10^{15}$ eV to $>10^{20}$ eV, and
residing in environments (such as starburst galaxies) in which CRs of rigidity
$E/Z< 10^{17}$ eV lose much of their energy to pion production. Identification
of the neutrino sources will allow one to identify the UHECR accelerators, to
resolve open questions related to the accelerator models, and to study neutrino
properties (related e.g. to flavor oscillations and coupling to gravity) with
an accuracy many orders of magnitude better than is currently possible. The
most promising method for identifying the sources is by association of a
neutrino with an electromagnetic signal accompanying a transient event
responsible for its generation. The neutrino flux that is produced within the
sources, and that may thus be directly associated with transient events, may be
significantly lower than the total observed neutrino flux, which may be
dominated by neutrino production at the environment in which the sources
reside.


title:
Pion and sigma meson dissociation in a modified NJL model at finite
  temperature

abstract:
  We investigate pion and sigma meson correlations in hot quark matter within a
modified NJL model. Special emphasis is on the transformation of mesonic bound
states to resonances (Mott dissociation) when due to the partial chiral
symmetry restoration with increasing temperature the threshold of
quark-antiquark continuum states drops below the meson mass at the
corresponding Mott temperature. The description is based on evaluating the
polarization functions for quark-antiquark (meson) correlations as a function
of the temperature and the results can be represented by introducing modulus
and phase of the complex propagator functions for the mesonic states. We study
the effect of modelling confinement by introducing a low-momentum cutoff in
loop integrals. We make the ansatz that this cutoff is identified with the
dynamically generated quark mass gap and find an increase of the continuum
threshold which makes the otherwise unbound sigma meson a bound state in the
vacuum. We discuss the in-medium behavior of the mesonic phase shifts including
the Mott effect and find accordance with the Levinson theorem.


title:
Interacting galaxies: co-rotating and counter-rotating systems with
  tidal tails

abstract:
  We analyse interacting galaxy pairs with evidence of tidal features in the
Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). The pairs were selected
within $z<0.1$ by requiring a projected separation $r_p < 50 \kpc$ and relative
radial velocity $\Delta V < 500 \kms$. We complete spectroscopic pairs using
galaxies with photometric redshifts considering $\Delta V_{phot} < 6800 \kms$,
taking into account the mean photometric redshift uncertainty. We classify by
visual inspection pairs of spirals into co-rotating and counter-rotating
systems. For a subsample of non-AGN galaxies, counter-rotating pairs have
larger star formation rates, and a higher fraction of young, star-forming
galaxies. These effects are enhanced by restricting to $r_p < 12 \kpc$. The
distributions of $C$, $D_n(4000)$ and $(M_u-M_r)$ for AGN galaxies show that
counter-rotating hosts have bluer colours and younger stellar population than
the co-rotating galaxies although the relative fractions of Seyfert, Liner,
Composite and Ambiguous AGN are similar. Also, counter-rotating hosts have more
powerful AGN as revealed by enhanced $Lum[OIII]$ values.
  The number of co-rotating systems is approximately twice the number of
counter-rotating pairs which could be owed to a more rapid evolution of
counter-rotating systems, besides possible different initial conditions of
these interacting pairs.


title: On the polyhedral cones of convex and concave vectors

abstract:
  Convex or concave sequences of $n$ positive terms, viewed as vectors in
$n$-space, constitute convex cones with $2n-2$ and $n$ extreme rays,
respectively. Explicit description is given of vectors spanning these extreme
rays, as well as of non-singular linear transformations between the positive
orthant and the simplicial cones formed by the positive concave vectors. The
simplicial cones of monotone convex and concave vectors can be described
similarly.


title: Results on neutrinoless double beta decay from GERDA Phase I

abstract:
  The GERmanium Detector Array, GERDA, is designed to search for neutrinoless
double beta (0$\nu\beta\beta$) decay of $^{76}$Ge and it is installed in the
Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. In this review, the
detection principle and detector setup of GERDA are described. Also, the main
physics results by GERDA Phase I, are discussed. They include the measurement
of the half-life of 2$\nu\beta\beta$ decay, the background decomposition of the
energy spectrum and the techniques for the discrimination of the background,
based on the pulse shape of the signal. In the last part of this paper, the
estimation of a limit on the half-life of 0$\nu\beta\beta$ ($T^{0\nu}_{1/2}
>2.1\cdot 10^{25}$ yr at 90% C.L.) and the comparison with previous results are
discussed. GERDA data from Phase I strongly disfavour the recent claim of
0$\nu\beta\beta$ discovery, based on data from the Heidelberg-Moscow
experiment.


title: Simulating and analyzing order book data: The queue-reactive model

abstract:
  Through the analysis of a dataset of ultra high frequency order book updates,
we introduce a model which accommodates the empirical properties of the full
order book together with the stylized facts of lower frequency financial data.
To do so, we split the time interval of interest into periods in which a well
chosen reference price, typically the mid price, remains constant. Within these
periods, we view the limit order book as a Markov queuing system. Indeed, we
assume that the intensities of the order flows only depend on the current state
of the order book. We establish the limiting behavior of this model and
estimate its parameters from market data. Then, in order to design a relevant
model for the whole period of interest, we use a stochastic mechanism that
allows for switches from one period of constant reference price to another.
Beyond enabling to reproduce accurately the behavior of market data, we show
that our framework can be very useful for practitioners, notably as a market
simulator or as a tool for the transaction cost analysis of complex trading
algorithms.


title: The photon magnetic moment problem revisited

abstract:
  The photon magnetic moment for radiation propagating in magnetized vacuum is
defined as a pseudo-tensor quantity, proportional to the external
electromagnetic field tensor. After expanding the eigenvalues of the
polarization operator in powers of $k^2$, we obtain approximate dispersion
equations (cubic in $k^2$), and analytic solutions for the photon magnetic
moment, valid for low momentum and/or large magnetic field.
  The paramagnetic photon experiences a red shift, with opposite sign than the
gravitational one, which differs for parallel and perpendicular polarizations.
It is due to the drain of photon transverse momentum and energy by the external
field. By defining an effective transverse momentum, the constancy of the speed
of light orthogonal to the field is guaranteed. We conclude that the
propagation of the photon non-parallel to the magnetic behaves as if there is a
quantum compression of vacuum or warp of space-time in an amount depending on
its angle with regard to the field.


title: Stationary solutions to a Vlasov equation for planetary rings

abstract:
  In this paper we consider a Vlasov or collisionless Boltzmann equation
describing the dynamics of planetary rings. We propose a simple physical model,
where the particles of the rings move under the gravitational Newtonian
potential of two primary bodies. We neglect the gravitational forces between
the particles. We use a perturbative technique, which allows to find explicit
solutions at the first order and solutions at the second order, solving a set
of two linear ordinary differential equations.


title:
Late evolution of relic gravitational waves in coupled dark energy
  models

abstract:
  In this paper we study the late evolution of Relic Gravitational Waves in
coupled dark energy models, where dark energy interacts with cold dark matter.
Relic Gravitational Waves are second tensorial order perturbations of the
Lemaitre-Friedman-Robertson-Walker metric and experiment an evolution ruled by
the scale factor of the metric. We and that the amplitude of Relic
Gravitational Waves is smaller in coupled dark energy models than in models
with non interacting dark energy . We also find that the amplitude of the waves
predicted by the models with coupling term proportional to the dark energy
density is smaller than those of the models with coupling term proportional to
dark matter density.


title:
The nonlinear Fourier transform for two-dimensional subcritical
  potentials

abstract:
  The inverse scattering method for the Novikov-Veselov equation is studied for
a larger class of Schr\"odinger potentials than could be handled previously.
Previous work concerns so-called conductivity type potentials, which have a
bounded positive solution at zero energy and are a nowhere dense set of
potentials. We relax this assumption to include logarithmically growing
positive solutions at zero energy. These potentials are stable under
perturbations. Assuming only that the potential is subcritical and has two weak
derivatives in a weighted Sobolev space, we prove that the associated
scattering transform can be inverted, and the original potential is recovered
from the scattering data.


title: Fourier coefficients of sextic theta series

abstract:
  This article focuses on the theta series on the 6-fold cover of GL$_2$. We
investigate the Fourier coefficients $\tau(r)$ of the theta series, and give
partially proven, partially conjectured values for $\tau(\pi)^2$, $\tau(\pi^2)$
and $\tau(\pi^4)$ for prime values $\pi$.


title: Wald tests when restrictions are locally singular

abstract:
  Wald-type tests are convenient because they allow one to test a wide array of
linear and nonlinear restrictions from a single unrestricted estimator; we
focus on the problem of implementing Wald-type tests for nonlinear
restrictions. We provide examples showing that Wald statistics in non-regular
cases can have several asymptotic distributions; the usual critical values
based on a chi-square distribution can both lead to under-rejections and
over-rejections; indeed, the Wald statistic may diverge under the null
hypothesis. We study the asymptotic distribution of Wald-type statistics for
the class of polynomial restrictions and show that the Wald statistic either
has a non-degenerate asymptotic distribution, or diverges to infinity. We
provide conditions for convergence and a general characterization of this
distribution. We provide bounds on the asymptotic distribution (when it
exists). In several cases of interest, this bound yields an easily available
conservative critical value. We propose an adaptive consistent strategy for
determining whether the asymptotic distribution exists and which form it takes.


title:
Interpreting 16S metagenomic data without clustering to achieve sub-OTU
  resolution

abstract:
  The standard approach to analyzing 16S tag sequence data, which relies on
clustering reads by sequence similarity into Operational Taxonomic Units
(OTUs), underexploits the accuracy of modern sequencing technology. We present
a clustering-free approach to multi-sample Illumina datasets that can identify
independent bacterial subpopulations regardless of the similarity of their 16S
tag sequences. Using published data from a longitudinal time-series study of
human tongue microbiota, we are able to resolve within standard 97% similarity
OTUs up to 20 distinct subpopulations, all ecologically distinct but with 16S
tags differing by as little as 1 nucleotide (99.2% similarity). A comparative
analysis of oral communities of two cohabiting individuals reveals that most
such subpopulations are shared between the two communities at 100% sequence
identity, and that dynamical similarity between subpopulations in one host is
strongly predictive of dynamical similarity between the same subpopulations in
the other host. Our method can also be applied to samples collected in
cross-sectional studies and can be used with the 454 sequencing platform. We
discuss how the sub-OTU resolution of our approach can provide new insight into
factors shaping community assembly.


title:
A Robust Model-free Approach for Rare Variants Association Studies
  Incorporating Gene-Gene and Gene-Environmental Interactions

abstract:
  Recently more and more evidence suggests that rare variants with much lower
minor allele frequencies play significant roles in disease etiology. Advances
in next-generation sequencing technologies will lead to many more rare variants
association studies. Several statistical methods have been proposed to assess
the effect of rare variants by aggregating information from multiple loci
across a genetic region and testing the association between the phenotype and
aggregated genotype. One limitation of existing methods is that they only look
into the marginal effects of rare variants but do not systematically take into
account effects due to interactions among rare variants and between rare
variants and environmental factors. In this article, we propose the summation
of partition approach (SPA), a robust model-free method that is designed
specifically for detecting both marginal effects and effects due to gene-gene
(G-G) and gene-environmental (G-E) interactions for rare variants association
studies. SPA has three advantages. First, it accounts for the interaction
information and gains considerable power in the presence of unknown and
complicated G-G or G-E interactions. Secondly, it does not sacrifice the
marginal detection power; in the situation when rare variants only have
marginal effects it is comparable with the most competitive method in current
literature. Thirdly, it is easy to extend and can incorporate more complex
interactions; other practitioners and scientists can tailor the procedure to
fit their own study friendly. Our simulation studies show that SPA is
considerably more powerful than many existing methods in the presence of G-G
and G-E interactions.


title: Pseudoharmonic oscillator in quantum mechanics with a minimal length

abstract:
  The pseudoharmonic oscillator potential is studied in non relativistic
quantum mechanics with a generalized uncertainty principle characterized by the
existence of a minimal length scale. By using a perturbative approach, we
analytically compute the correction to the energy spectrum in the first order
of the minimal length parameter \b{eta}. We investigate the effect of this
fundamental length on the vibration-rotation energy levels of diatomic
molecules with this potential function interaction. We explicitly show that the
minimal length would have some importance in studying the spectra of diatomic
molecules.


title: Generalized epidemic process on modular networks

abstract:
  Social reinforcement and modular structure are two salient features observed
in the spreading of behavior through social contacts. In order to investigate
the interplay between these two features, we study the generalized epidemic
process on modular networks with equal-sized finite communities and adjustable
modularity. Using the analytical approach originally applied to clique-based
random networks, we show that the system exhibits a bond-percolation type
continuous phase transition for weak social reinforcement, whereas a
discontinuous phase transition occurs for sufficiently strong social
reinforcement. Our findings are numerically verified using the finite-size
scaling analysis and the crossings of the bimodality coefficient.


title: Fundamental invariants of systems of ODEs of higher order

abstract:
  We find the complete set of fundamental invariants for systems of ordinary
differential equations of order $\ge 4$ under the group of point
transformations generalizing similar results for contact invariants of a single
ODE and point invariants of systems of the second and the third order.
  It turns out that starting from systems of order $(k+1)\ge 4$, the complete
set of fundamental invariants is formed by $k$ generalized Wilczynski
invariants coming from the linearized system and an additional invariant of
degree 2.


title:
Tunneling of Massive Dirac Fermions in Graphene through Time-periodic
  Potential

abstract:
  The energy spectrum of graphene sheet with a single barrier structure having
a time periodic oscillating height and subjected to magnetic field is analyzed.
The corresponding transmission is studied as function of the obtained energy
and the potential parameters. Quantum interference within the oscillating
barrier has an important effect on quasiparticles tunneling. In particular the
time-periodic electromagnetic field generates additional sidebands at energies
\epsilon + l\hbar \omega (l=0,\pm 1, \cdots) in the transmission probability
originating from the photon absorption or emission within the oscillating
barrier. Due to numerical difficulties in truncating the resulting coupled
channel equations we limited ourselves to low quantum channels, i.e. l=0,\pm 1.


title: Quantitative uniqueness of elliptic equations

abstract:
  Based on a variant of frequency function, we improve the vanishing order of
solutions for Schr\"{o}dinger equations which describes quantitative behavior
of strong uniqueness continuation property. For the first time, we investigate
the quantitative uniqueness of higher order elliptic equations and show the
vanishing order of solutions. Furthermore, strong unique continuation is
established for higher order elliptic equations using this variant of frequency
function.


title: Many-Body Localization: Concepts and Simple Models

abstract:
  We review recent results on many-body localization for two explicitly
analyzable models of many-body quantum systems, the XY spin chain in
transversal magnetic field as well as interacting systems of harmonic quantum
oscillators. In both models the presence of disorder leads to dynamical
localization in the form of zero-velocity Lieb-Robinson bounds and to
exponential decay of ground state correlations. Moreover, for oscillator
systems one can also show exponential decay of thermal states as well as an
area law bound for the entanglement entropy of ground and thermal states. The
key fact which allows a rigorous analysis of these models is that they are
given by many-body Hamiltonians which can be reduced to effective single
particle Hamiltonians.


title:
BPS solution for eleven-dimensional supergravity with a conical defect
  configuration

abstract:
  In this work, we found the solution for the field equations of
eleven-dimensional supergravity with a BPS conical topological defect
configuration. We chose the solutions that corresponded to a M2-brane where the
space-time presents the co-dimension two. The source of the topological defect
is a sigma model where the brane tension is connected with the angular deficit.
We analyzed the Killing spinor equations, a 3-form gauge potential and
Einstein's equations, proving that it is possible to find a full solution for
the system. We analyzed the near-horizon limit proving that it is possible to
obtain an $AdS_4 \times S^1 \times \mathbb{E}^6 $ geometry for certain values
of the brane tension. We also discussed some applications in the strong
coupling theory for condensed matter systems.


title: SpeedMachines: Anytime Structured Prediction

abstract:
  Structured prediction plays a central role in machine learning applications
from computational biology to computer vision. These models require
significantly more computation than unstructured models, and, in many
applications, algorithms may need to make predictions within a computational
budget or in an anytime fashion. In this work we propose an anytime technique
for learning structured prediction that, at training time, incorporates both
structural elements and feature computation trade-offs that affect test-time
inference. We apply our technique to the challenging problem of scene
understanding in computer vision and demonstrate efficient and anytime
predictions that gradually improve towards state-of-the-art classification
performance as the allotted time increases.


title: Quantization of Emergent Gravity

abstract:
  Emergent gravity is based on a novel form of the equivalence principle known
as the Darboux theorem or the Moser lemma in symplectic geometry stating that
the electromagnetic force can always be eliminated by a local coordinate
transformation as far as spacetime admits a symplectic structure, in other
words, a microscopic spacetime becomes noncommutative (NC). If gravity emerges
from U(1) gauge theory on NC spacetime, this picture of emergent gravity
suggests a completely new quantization scheme where quantum gravity is defined
by quantizing spacetime itself, leading to a dynamical NC spacetime. Therefore
the quantization of emergent gravity is radically different from the
conventional approach trying to quantize a phase space of metric fields. This
approach for quantum gravity allows a background independent formulation where
spacetime as well as matter fields is equally emergent from a universal vacuum
of quantum gravity.


title: First-passage time of Brownian motion with dry friction

abstract:
  We provide an analytic solution to the first-passage time (FPT) problem of a
piecewise-smooth stochastic model, namely Brownian motion with dry friction,
using two different but closely related approaches which are based on
eigenfunction decompositions on the one hand and on the backward Kolmogorov
equation on the other. For the simple case containing only dry friction, a
phase transition phenomenon in the spectrum is found which relates to the
position of the exit point, and which affects the tail of the FPT distribution.
For the model containing as well a driving force and viscous friction the
impact of the corresponding stick-slip transition and of the transition to
ballistic exit is evaluated quantitatively. The proposed model is one of the
very few cases where FPT properties are accessible by analytical means.


title:
Non-universal gaugino masses and semi-natural supersymmetry in view of
  the Higgs boson discovery

abstract:
  I consider models with non-universal gaugino masses at the gauge coupling
unification scale, taking into account the Higgs boson discovery. Viable
regions of parameter space are mapped and studied in the case of
non-universality following from an F-term in a linear combination of singlet
and adjoint representations of SU(5). I consider, in particular, "semi-natural"
models that have small \mu, with gaugino masses dominating the supersymmetry
breaking terms at high energies. Higgsino-like particles are then much lighter
than all other superpartners, and the prospects for discovery at the Large
Hadron Collider can be extremely challenging.


title: Embedding structures associated with Riordan arrays and moment matrices

abstract:
  Every ordinary Riordan array contains two naturally embedded Riordan arrays.
We explore this phenomenon, and we compare it to the situation for certain
moment matrices of families of orthogonal polynomials.


title: Explicit estimates for solutions of mixed elliptic problems

abstract:
  We deal with the existence of quantitative estimates for solutions of mixed
problems to an elliptic second order equation in divergence form with
discontinuous coefficient. Our concern is to estimate the solutions with
explicit constants, for domains in $\mathbb{R}^n$ ($n\geq 2$) of class
$C^{0,1}$. The existence of $L^\infty$ and $W^{1,q}$-estimates is assured for
$q=2$ and any $q<n/(n-1)$ (depending on the data), whenever the coefficient is
only measurable and bounded. The proof method of the quantitative
$L^\infty$-estimates is based on the DeGiorgi technique developed by
Stampacchia. By using the potential theory, we derive $W^{1,p}$-estimates for
different ranges of the exponent $p$ depending on that the coefficient is
either Dini-continuous or only measurable and bounded. In this process, we
establish new existences of Green functions on such domains. The last but not
least concern is to unify (whenever possible) the proofs of the estimates to
the extreme Dirichlet and Neumann cases of the mixed problem.


title:
Cannibalization and Rebirth in the NGC5387 System. I. The Stellar Stream
  & Star Forming Region

abstract:
  We have identified a low surface brightness stellar stream from visual
inspection of SDSS imaging for the edge-on, spiral galaxy NGC5387. A blue
overdensity was also identified in SDSS coincident with the stream intersection
with the NGC5387 disk. The overdensity was also detected in the GALEX Deep
Imaging Survey and found to contribute 38% of the total FUV integrated flux
from NGC5387, which suggests that the region is actively forming stars. Deeper
imaging was acquired with the Vatican Advanced Technology Telescope (VATT) in
the B, V, and R filters that confirmed the presence of both the stellar stream
and the blue overdensity. Analysis of the VATT photometry indicates the stellar
stream is red in color, B-V = 0.7, and has a stellar mass of 6x10^8
M$_{\odot}$, which implies a merger ratio of 1:50. Assessment of the stream
morphology suggests that the merger event has a circular radius, R~16 kpc, the
stream formed in ~400 Myr, and the progenitor had a total mass of ~2x10
M$_{\odot}$. Spectroscopy from LBT+MODS1 was used to determine that the blue
overdensity is at the same redshift as NGC5387, consists of young stellar
populations (~10 Myr), is metal-poor (12 + log(O/H) = 8.03), and forming stars
at an enhanced rate (~1-3 M$_{\odot}$/year) given its total stellar mass
(2x10^7 M$_{\odot}$). Several interpretations are posited to explain these
observational data, of which the most likely are (i) that the blue overdensity
is a region of enhanced star formation in the outer disk of NGC5387 induced by
the minor accretion event, and (ii) that the blue overdensity is the progenitor
of the stellar stream undergoing a period of enhanced star formation as a
result of its interaction with NGC5387. Confirmation and theoretical
exploration of these scenarios are presented in a companion paper.


title: The free group does not have the finite cover property

abstract:
  We prove that the first order theory of nonabelian free groups eliminates the
"there exists infinitely many" quantifier (in eq). Equivalently, since the
theory of nonabelian free groups is stable, it does not have the finite cover
property. We also extend our results to torsion-free hyperbolic groups under
some conditions.


title: Contractive Families on Compact Spaces

abstract:
  A family f_1,...,f_n of operators on a complete metric space X is called
contractive if there exists lambda < 1 such that for any x,y in X we have
d(f_i(x),f_i(y)) leq lambda d(x,y) for some i. Stein conjectured that for any
contractive family there is some composition of the operators f_i that has a
fixed point. Austin gave a counterexample to this, and asked if Stein's
conjecture is true if we restrict to compact spaces. Our aim in this paper is
to show that, even for compact spaces, Stein's conjecture is false.


title: Toeplitz Quantization without Measure or Inner Product

abstract:
  This note is a follow-up to a recent paper by the author. Most of that theory
is now realized in a new setting where the vector space of symbols is not
necessarily an algebra nor is it equipped with an inner product, although it
does have a conjugation. As in the previous paper one does not need to put a
measure on this vector space. A Toeplitz quantization is defined and shown to
have most of the properties as in the previous paper, including creation and
annihilation operators. As in the previous paper this theory is implemented by
densely defined Toeplitz operators which act in a Hilbert space, where there is
an inner product, of course. Planck's constant also plays a role in the
canonical commutation relations of this theory.


title: The Phase Diagram of Strong Coupling QCD including Gauge Corrections

abstract:
  The strong coupling limit of lattice QCD with staggered fermions has been
studied for decades, both via Monte Carlo and via mean field theory. In this
model, the finite density sign problem can be made mild and the full phase
diagram can be obtained, even in the chiral limit. It is however desirable to
understand the effect of a finite lattice gauge coupling $\beta$ on the phase
diagram in the $\mu-T$ plane in order to understand how it evolves into the
phase diagram of continuum QCD. Here we discuss how to construct a partition
function for non-zero lattice coupling, exact to $\mathcal{O}(\beta)$, and
present corresponding Monte Carlo results, in particular for corrections to the
chiral susceptibility and to the phase diagram.


title:
Prospects for GeV-TeV detection of short gamma-ray bursts with extended
  emission

abstract:
  We discuss the GeV to TeV photon emission of gamma-ray bursts (GRBs) within
the refreshed shock and the continuous injection scenarios, motivated by the
observation of extended emission in a substantial fraction of short GRBs. In
the first model we assume that the central engine emits promptly material with
a range of Lorentz factors. When the fastest shell starts to decelerate, it
drives a forward shock into the ambient medium and a reverse shock in the
ejecta. These shocks are reenergized by the slower and later arriving material.
In the second model we assume that there is a continued ejection of material
over an extended time, and the continuously arriving new material keeps
reenergizing the shocks formed by the preceding shells of ejecta. We calculate
the synchrotron and synchrotron self-Compton radiation components for the
forward and reverse shocks and find that prospective and current GeV to TeV
range instruments such as CTA, HAWC, VERITAS, MAGIC and HESS have a good chance
to detect afterglows of short bursts with extended emission, assuming a
reasonable response time.


title: A new crystalline phase in magnetar crusts

abstract:
  We show that ions at the low densities and high magnetic fields relevant to
the outer crust of magnetars form a novel crystalline phase where ions are
strongly coupled along the magnetic field and loosely coupled in the transverse
direction. The underlying cause is the anisotropic screening of the Coulomb
force by electrons in the presence of a strongly quantizing magnetic field
which leads to Friedel oscillations in the ion-ion potential. In particular,
the Friedel oscillations are much longer-ranged in the direction of the
magnetic field than is the case in the absence of magnetic fields, a factor
that has been neglected in previous studies. These "Friedel crystals" have very
anisotropic elastic moduli, with potentially interesting implications for the
Quasi-periodic Oscillations seen in the X-ray flux of magnetars during their
giant flares. We find the minimum energy configuration of ions taking into
account these anisotropic effects and find that, depending on the density,
temperature and magnetic field strength, different lattice structures (fcc, hcp
or bcc oriented in different ways in relation to the magnetic field) are
favored.


title: Next-to-leading order diphoton+2-jet production at the LHC

abstract:
  We present results from a recent calculation of prompt photon-pair production
in association with two jets to next-to-leading order (NLO) at the LHC. The
virtual contribution is evaluated using the BlackHat library, a numerical
implementation of on-shell methods for one-loop amplitudes, in conjunction with
SHERPA. We study four sets of cuts: standard jet cuts, a set of Higgs-related
cuts suggested by ATLAS, and corresponding sets which isolate the kinematic
region where the process becomes the largest background to Higgs production via
vector-boson fusion.


title:
Optical spectra of 5 new Be/X-ray Binaries in the Small Magellanic Cloud
  and the link of the supergiant B[e] star LHA 115-S 18 with an X-ray source

abstract:
  The Small Magellanic Cloud (SMC) is well known to harbor a large number of
High-Mass X-ray Binaries (HMXBs). The identification of their optical
counterparts provides information on the nature of the donor stars and can help
to constrain the parameters of these systems and their evolution. We obtained
optical spectra for a number of HMXBs identified in previous Chandra and
XMM-Newton surveys of the SMC using the AAOmega/2dF fiber-fed spectrograph at
the Anglo-Australian Telescope. We find 5 new Be/X-ray binaries (BeXRBs;
including a tentative one), by identifying the spectral type of their optical
counterparts, and we confirm the spectral classification of an additional 15
known BeXRBs. We compared the spectral types, orbital periods, and
eccentricities of the BeXRB populations in the SMC and the Milky Way and we
find marginal evidence for difference between the spectral type distributions,
but no statistically significant differences for the orbital periods and the
eccentricities. Moreover, our search revealed that the well known supergiant
B[e] star LHA 115-S 18 (or AzV 154) is associated with the weak X-ray source
CXOU J005409.57-724143.5. We provide evidence that the supergiant star LHA
115-S 18 is the optical counterpart of the X-ray source, and we discuss
different possibilities of the origin of its low X-ray luminosity (Lx ~ 4 x
10^33 erg/s).


title:
An analysis of the interaction between influenza and respiratory
  syncytial virus based on acute respiratory infection records

abstract:
  Under the hypothesis that both influenza and respiratory syncytial virus
(RSV) are the two leading causes of acute respiratory infections (ARI), in this
paper we have used a standard two-pathogen epidemic model as a regressor to
explain, on a yearly basis, high season ARI data in terms of the contact rates
and initial conditions of the mathematical model. The rationale is that ARI
high season is a transient regime of a noisy system, e.g., the system is driven
away from equilibrium every year by fluctuations in variables such as humidity,
temperature, viral mutations and human behavior. Using the value of the
replacement number as a phenotypic trait associated to fitness, we provide
evidence that influenza and RSV coexists throughout the ARI high season through
superinfection.


title:
Three-dimensional phase-field study of crack-seal microstructures -
  Insights from innovative post-processing techniques

abstract:
  Numerical simulations of vein evolution contribute to a better understanding
of processes involved in their formation and possess the potential to provide
invaluable insights into the rock deformation history and fluid flow pathways.
The primary aim of the present article is to investigate the influence of a
realistic boundary condition, i.e. an algorithmically generated fractal
surface, on the vein evolution in 3-D using a thermodynamically consistent
approach, while explaining the benefits of accounting for an extra
dimensionality. The 3-D simulation results are supplemented by innovative
numerical post-processing and advanced visualization techniques. The new
methodologies to measure the tracking efficiency demonstrate the importance of
accounting the temporal evolution; no such information is usually accessible in
field studies and notoriously difficult to obtain from laboratory experiments
as well. The grain growth statistics obtained by numerically post-processing
the 3-D computational microstructures explain the pinning mechanism which leads
to arrest of grain boundaries/multi-junctions by crack peaks, thereby,
enhancing the tracking behavior.


title:
An NMF solution for the Petri Nets to State Charts case study at the TTC
  2013

abstract:
  Software systems are getting more and more complex. Model-driven engineering
(MDE) offers ways to handle such increased complexity by lifting development to
a higher level of abstraction. A key part in MDE are transformations that
transform any given model into another. These transformations are used to
generate all kinds of software artifacts from models. However, there is little
consensus about the transformation tools. Thus, the Transformation Tool Contest
(TTC) 2013 aims to compare different transformation engines. This is achieved
through three different cases that have to be tackled. One of these cases is
the Petri Net to State Chart case. A solution has to transform a Petri Net to a
State Chart and has to derive a hierarchical structure within the State Chart.
This paper presents the solution for this case using NMF Transformations as
transformation engine.


title: (Non)-Dissipative Hydrodynamics on Embedded Surfaces

abstract:
  We construct the theory of dissipative hydrodynamics of uncharged fluids
living on embedded space-time surfaces to first order in a derivative expansion
in the case of codimension-1 surfaces (including fluid membranes) and the
theory of non-dissipative hydrodynamics to second order in a derivative
expansion in the case of codimension higher than one under the assumption of no
angular momenta in transverse directions to the surface. This construction
includes the elastic degrees of freedom, and hence the corresponding transport
coefficients, that take into account transverse fluctuations of the geometry
where the fluid lives. Requiring the second law of thermodynamics to be
satisfied leads us to conclude that in the case of codimension-1 surfaces the
stress-energy tensor is characterized by 2 hydrodynamic and 1 elastic
independent transport coefficient to first order in the expansion while for
codimension higher than one, and for non-dissipative flows, the stress-energy
tensor is characterized by 7 hydrodynamic and 3 elastic independent transport
coefficients to second order in the expansion. Furthermore, the constraints
imposed between the stress-energy tensor, the bending moment and the entropy
current of the fluid by these extra non-dissipative contributions are fully
captured by equilibrium partition functions. This analysis constrains the Young
modulus which can be measured from gravity by elastically perturbing black
branes.


title:
The impact of angular momentum on black hole accretion rates in
  simulations of galaxy formation

abstract:
  Feedback from energy liberated by gas accretion onto black holes (BHs) is an
attractive mechanism to explain the exponential cut-off at the massive end of
the galaxy stellar mass function (SMF). Semi-analytic models of galaxy
formation in which this form of feedback is assumed to suppress cooling in
haloes where the gas cooling time is large compared to the dynamical time do
indeed achieve a good match to the observed SMF. Furthermore, hydrodynamic
simulations of individual halos in which gas is assumed to accrete onto the
central BH at the Bondi rate have shown that a self-regulating regime is
established in which the BH grows just enough to liberate an amount of energy
comparable to the thermal energy of the halo. However, this process is
efficient at suppressing the growth not only of massive galaxies but also of
galaxies like the Milky Way, leading to disagreement with the observed SMF. The
Bondi accretion rate, however, is inappropriate when the accreting material has
angular momentum. We present an improved accretion model that takes into
account the circularisation and subsequent viscous transport of infalling
material and include it as a "subgrid" model in hydrodynamic simulations of the
evolution of halos with a wide range of masses. The resulting accretion rates
are generally low in low mass ($\lsim 10^{11.5} \msun$) halos, but show
outbursts of Eddington-limited accretion during galaxy mergers. During
outbursts these objects strongly resemble quasars. In higher mass haloes, gas
accretion occurs continuously, typically at $~10$ % of the Eddington rate,
which is conducive to the formation of radio jets. The resulting dependence of
the accretion behaviour on halo mass induces a break in the relation between
galaxy stellar mass and halo mass in these simulations that matches
observations.


title: Getting more flavour out of one-flavour QCD

abstract:
  We argue that no notion of flavour is necessary when performing amplitude
calculations in perturbative QCD with massless quarks. We show this explicitly
at tree-level, using a flavour recursion relation to obtain multi-flavoured QCD
from one-flavour QCD. The method relies on performing a colour decomposition,
under which the one-flavour primitive amplitudes have a structure which is
restricted by planarity and cyclic ordering. An understanding of SU(3)_c group
theory relations between QCD primitive amplitudes and their organisation around
the concept of a Dyck tree is also necessary. The one-flavour primitive
amplitudes are effectively N=1 supersymmetric, and a simple consequence is that
all of tree-level massless QCD can be obtained from Drummond and Henn's closed
form solution to tree-level N=4 super Yang-Mills theory.


title:
Accretion disks around binary black holes of unequal mass: GRMHD
  simulations near decoupling

abstract:
  We report on simulations in general relativity of magnetized disks onto black
hole binaries. We vary the binary mass ratio from 1:1 to 1:10 and evolve the
systems when they orbit near the binary-disk decoupling radius. We compare
(surface) density profiles, accretion rates (relative to a single, non-spinning
black hole), variability, effective $\alpha$-stress levels and luminosities as
functions of the mass ratio. We treat the disks in two limiting regimes: rapid
radiative cooling and no radiative cooling. The magnetic field lines clearly
reveal jets emerging from both black hole horizons and merging into one common
jet at large distances. The magnetic fields give rise to much stronger shock
heating than the pure hydrodynamic flows, completely alter the disk structure,
and boost accretion rates and luminosities. Accretion streams near the horizons
are among the densest structures; in fact, the 1:10 no-cooling evolution
results in a refilling of the cavity. The typical effective temperature in the
bulk of the disk is $\sim 10^5 (M/10^8 M_\odot)^{-1/4} (L/L_{\rm edd})^{1/4}
{\rm K}$ yielding characteristic thermal frequencies $\sim 10^{15} (M/10^8
M_\odot)^{-1/4} (L/L_{\rm edd})^{1/4}(1+z)^{-1}{\rm Hz} $. These systems are
thus promising targets for many extragalactic optical surveys, such as LSST,
WFIRST, and PanSTARRS.


title: Baryon production from embedded metastable strings

abstract:
  We quantify the baryon anti-baryon production generated by a metastable
cosmic string, similar to the embedded pion string. More precisely, we study
skyrmion production mediated by instantons generated by a pion-like metastable
string in contact with a thermal bath, and interpret these Skyrmions as
baryons. As shown in a previous work, the core of such a metastable string can
melt due to quantum tunneling in the charged field direction. The specific
configuration of our string containing 4 scalar fields out of equilibrium in
contact with a thermal bath is shown to yield skyrmion production with partial
or integer winding number. In this work, we describe and quantify this skyrmion
production per unit length of the string. We also evaluate the skyrmion-anti
skyrmions production by a dense string network by invoking similarity with the
Skyrmion production in a phase transition.


title: GHOSTS I: A New Faint very Isolated Dwarf Galaxy at D = 12 +/- 2 Mpc

abstract:
  We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS
data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick
disk, and Star clusters) fields. Its detected individual stars populate an
approximately one magnitude range of its luminosity function (LF). Using
synthetic color-magnitude diagrams (CMDs) to compare with the galaxy's CMD, we
find that the colors and magnitudes of GHOSTS I's individual stars are most
consistent with being young helium-burning and asymptotic giant branch stars at
a distance of 12 +/- 2 Mpc. Morphologically, GHOSTS I appears to be actively
forming stars, so we tentatively classify it as a dwarf irregular (dIrr)
galaxy, although future HST observations deep enough to resolve a larger
magnitude range in its LF are required to make a more secure classification.
GHOSTS I's absolute magnitude is $M_V = -9.85^{+ 0.40}_{- 0.33}$, making it one
of the least luminous dIrr galaxies known, and its metallicity is lower than
[Fe/H] =-1.5 dex. The half-light radius of GHOSTS I is 226 +/- 38 pc and its
ellipticity is 0.47 +/- 0.07, similar to Milky Way and M31 dwarf satellites at
comparable luminosity. There are no luminous massive galaxies or galaxy
clusters within ~ 4 Mpc from GHOSTS I that could be considered as its host,
making it a very isolated dwarf galaxy in the Local Universe.


title: On the mass function of stars growing in a flocculent medium

abstract:
  Stars form in regions of very inhomogeneous densities and may have chaotic
orbital motions. This leads to a time variation of the accretion rate, which
will spread the masses over some mass range. We investigate the mass
distribution functions that arise from fluctuating accretion rates in
non-linear accretion, $\dot{m} \propto m^{\alpha}$. The distribution functions
evolve in time and develop a power law tail attached to a lognormal body, like
in numerical simulations of star formation. Small fluctuations may be modelled
by a Gaussian and develop a power-law tail $\propto m^{-\alpha}$ at the
high-mass side for $\alpha > 1$ and at the low-mass side for $\alpha < 1$.
Large fluctuations require that their distribution is strictly positive, for
example, lognormal. For positive fluctuations the mass distribution function
develops the power-law tail always at the high-mass hand side, independent of
$\alpha$ larger or smaller than unity.
  Furthermore, we discuss Bondi-Hoyle accretion in a supersonically turbulent
medium, the range of parameters for which non-linear stochastic growth could
shape the stellar initial mass function, as well as the effects of a
distribution of initial masses and growth times.


title:
Molecular gas in the centre of nearby galaxies from VLT/SINFONI integral
  field spectroscopy - II. Kinematics

abstract:
  We present an analysis of the H2 emission-line gas kinematics in the inner <
4 arcsec radius of six nearby spiral galaxies, based on AO-assisted
integral-field observations obtained in the K-band with SINFONI/VLT. Four of
the six galaxies in our sample display ordered H2 velocity fields, consistent
with gas moving in the plane of the galaxy and rotating in the same direction
as the stars. However, the gas kinematics is typically far from simple circular
motion. We can classify the observed velocity fields into four different types
of flows, ordered by increasing complexity: (1) circular motion in a disc
(NGC3351); (2) oval motion in the galaxy plane (NGC3627 and NGC4536); (3)
streaming motion superimposed on circular rotation (NGC4501); and (4)
disordered streaming motions (NGC4569 and NGC4579). The H2 velocity dispersion
in the galaxies is usually higher than 50 km/s in the inner 1-2 arcsec radii.
The four galaxies with ordered kinematics have v/sigma < 1 at radii less than
40-80 pc. The radius at which v/sigma = 1 is independent of the type of nuclear
activity. While the low values of v/sigma could be taken as an indication of a
thick disc in the innermost regions of the galaxies, other lines of evidence
(e.g. H2 morphologies and velocity fields) argue for a thin disc interpretation
in the case of NGC3351 and NGC4536. We discuss the implications of the high
values of velocity dispersion for the dynamics of the gaseous disc and suggest
caution when interpreting the velocity dispersion of ionized and warm tracers
as being entirely dynamical. Understanding the nature and role of the velocity
dispersion in the gas dynamics, together with the full 2D information of the
gas, is essential for obtaining accurate black hole masses from gas kinematics.


title:
Multi-wavelength emissions from the millisecond pulsar binary PSR
  J1023+0038 during an accretion active state

abstract:
  Recent observations strongly suggest that the millisecond pulsar binary PSR
J1023+0038 has developed an accretion disk since 2013 June. We present a
multi-wavelength analysis of PSR J1023+0038, which reveals that 1) its
gamma-rays suddenly brightened within a few days in June/July 2013 and has
remained at a high gamma-ray state for several months; 2) both UV and X-ray
fluxes have increased by roughly an order of magnitude, and 3) the spectral
energy distribution has changed significantly after the gamma-ray sudden flux
change. Time variabilities associated with UV and X-rays are on the order of
100-500 seconds and 50-100 seconds, respectively. Our model suggests that a
newly formed accretion disk due to the sudden increase of the stellar wind
could explain the changes of all these observed features. The increase of UV is
emitted from the disk, and a new component in gamma-rays is produced by inverse
Compton scattering between the new UV component and pulsar wind. The increase
of X-rays results from the enhancement of injection pulsar wind energy into the
intra-binary shock due to the increase of the stellar wind. We also predict
that the radio pulses may be blocked by the evaporated winds from the disk and
the pulsar is still powered by rotation.


title: Tracing the Evolution of High Redshift Galaxies Using Stellar Abundances

abstract:
  This paper presents the first results from a model for chemical evolution
that can be applied to N-body cosmological simulations and quantitatively
compared to measured stellar abundances from large astronomical surveys. This
model convolves the chemical yield sets from a range of stellar nucleosynthesis
calculations (including AGB stars, Type Ia and II supernovae, and stellar wind
models) with a user-specified stellar initial mass function (IMF) and
metallicity to calculate the time-dependent chemical evolution model for a
"simple stellar population" of uniform metallicity and formation time. These
simple stellar population models are combined with a semi-analytic model for
galaxy formation and evolution that uses merger trees from N-body cosmological
simulations to track several $\alpha$- and iron-peak elements for the stellar
and multiphase interstellar medium components of several thousand galaxies in
the early ($z \geq 6$) universe. The simulated galaxy population is then
quantitatively compared to two complementary datasets of abundances in the
Milky Way stellar halo, and is capable of reproducing many of the observed
abundance trends. The observed abundance ratio distributions are qualitatively
well matched by our model, and the observational data is best reproduced with a
Chabrier IMF, a chemically-enriched star formation efficiency of $0.2$, and a
redshift of reionization of $7$.