title: Is a good offensive always the best defense?

abstract:
  A checkers-like model game with a simplified set of rules is studied through
extensive simulations of agents with different expertise and strategies. The
introduction of complementary strategies, in a quite general way, provides a
tool to mimic the basic ingredients of a wide scope of real games. We find that
only for the player having the higher offensive expertise (the dominant player
), maximizing the offensive always increases the probability to win. For the
non-dominant player, interestingly, a complete minimization of the offensive
becomes the best way to win in many situations, depending on the relative
values of the defense expertise. Further simulations on the interplay of
defense expertise were done separately, in the context of a fully-offensive
scenario, offering a starting point for analytical treatments. In particular,
we established that in this scenario the total number of moves is defined only
by the player with the lower defensive expertise. We believe that these results
stand for a first step towards a new way to improve decisions-making in a large
number of zero-sum real games.


title:
The specific shapes of gender imbalance in scientific authorships: a
  network approach

abstract:
  Gender differences in collaborative research have received little attention
when compared with the growing importance that women hold in academia and
research. Unsurprisingly, most of bibliometric databases have a strong lack of
directly available information by gender. Although empirical-based network
approaches are often used in the study of research collaboration, the studies
about the influence of gender dissimilarities on the resulting topological
outcomes are still scarce. Here, networks of scientific subjects are used to
characterize patterns that might be associated to five categories of
authorships which were built based on gender. We find enough evidence that
gender imbalance in scientific authorships brings a peculiar trait to the
networks induced from papers published in Web of Science (WoS) indexed journals
of Economics over the period 2010-2015 and having at least one author
affiliated to a Portuguese institution. Our results show the emergence of a
specific pattern when the network of co-occurring subjects is induced from a
set of papers exclusively authored by men. Such a male-exclusive authorship
condition is found to be the solely responsible for the emergence that
particular shape in the network structure. This peculiar trait might facilitate
future network analyses of research collaboration and interdisciplinarity.


title: On Simulated Annealing Dedicated to Maximin Latin Hypercube Designs

abstract:
  The goal of our research was to enhance local search heuristics used to
construct Latin Hypercube Designs. First, we introduce the \textit{1D-move}
perturbation to improve the space exploration performed by these algorithms.
Second, we propose a new evaluation function $\psi_{p,\sigma}$ specifically
targeting the Maximin criterion.
  Exhaustive series of experiments with Simulated Annealing, which we used as a
typically well-behaving local search heuristics, confirm that our goal was
reached as the result we obtained surpasses the best scores reported in the
literature. Furthermore, the $\psi_{p,\sigma}$ function seems very promising
for a wide spectrum of optimization problems through the Maximin criterion.


title:
Unit-linked life insurance policies: optimal hedging in partially
  observable market models

abstract:
  In this paper we investigate the hedging problem of a unit-linked life
insurance contract via the local risk-minimization approach, when the insurer
has a restricted information on the market. In particular, we consider an
endowment insurance contract, that is a combination of a term insurance policy
and a pure endowment, whose final value depends on the trend of a stock market
where the premia the policyholder pays are invested. We assume that the stock
price process dynamics depends on an exogenous unobservable stochastic factor
that also influences the mortality rate of the policyholder. To allow for
mutual dependence between the financial and the insurance markets, we use the
progressive enlargement of filtration approach. We characterize the optimal
hedging strategy in terms of the integrand in the Galtchouk-Kunita-Watanabe
decomposition of the insurance claim with respect to the minimal martingale
measure and the available information flow. We provide an explicit formula by
means of predictable projection of the corresponding hedging strategy under
full information with respect to the natural filtration of the risky asset
price and the minimal martingale measure. Finally, we discuss applications in a
Markovian setting via filtering.


title: Conformal flow on $S^3$ and weak field integrability in AdS$_4$

abstract:
  We consider the conformally invariant cubic wave equation on the Einstein
cylinder $\mathbb{R} \times \mathbb{S}^3$ for small rotationally symmetric
initial data. This simple equation captures many key challenges of nonlinear
wave dynamics in confining geometries, while a conformal transformation relates
it to a self-interacting conformally coupled scalar in four-dimensional anti-de
Sitter spacetime (AdS$_4$) and connects it to various questions of AdS
stability. We construct an effective infinite-dimensional time-averaged
dynamical system accurately approximating the original equation in the weak
field regime. It turns out that this effective system, which we call the
conformal flow, exhibits some remarkable features, such as low-dimensional
invariant subspaces, a wealth of stationary states (for which energy does not
flow between the modes), as well as solutions with nontrivial exactly periodic
energy flows. Based on these observations and close parallels to the cubic
Szego equation, which was shown by Gerard and Grellier to be Lax-integrable, it
is tempting to conjecture that the conformal flow and the corresponding weak
field dynamics in AdS$_4$ are integrable as well.

categories: math.AP gr-qc hep-th math-ph math.MP nlin.SI


title:
Lebesgue decomposition of functionals and unique preduals for commutants
  modulo normed ideals

abstract:
  We prove an analogue of the Lebesgue decomposition for continuous functionals
on the commutant modulo a reflexive normed ideal of an n-tuple of hermitian
operators for which there are quasicentral approximate units relative to the
normed ideal. Using results of Godefroy-Talagrand and Pfitzner we derive from
this strong uniqueness of the predual of such a commutant modulo a normed
ideal.


title: Moebius and sub-Moebius structures

abstract:
  We introduce a notion of a sub-Moebius structure and find necessary and
sufficient conditions under which a sub-Moebius structure is a Moebius
structure. We show that on the boundary at infinity of every Gromov hyperbolic
space Y there is a canonical sub-Moebius structure which is invariant under
isometries of Y such that the sub-Moebius topology on the boundary coincides
with the standard one.


title: Dynamics of tidally captured planets in the Galactic Center

abstract:
  Recent observations suggest ongoing planet formation in the innermost parsec
of the Galactic center (GC). The super-massive black hole (SMBH) might strip
planets or planetary embryos from their parent star, bringing them close enough
to be tidally disrupted. Photoevaporation by the ultraviolet field of young
stars, combined with ongoing tidal disruption, could enhance the near-infrared
luminosity of such starless planets, making their detection possible even with
current facilities. In this paper, we investigate the chance of planet tidal
captures by means of high-accuracy N-body simulations exploiting Mikkola's
algorithmic regularization. We consider both planets lying in the clockwise
(CW) disk and planets initially bound to the S-stars. We show that tidally
captured planets remain on orbits close to those of their parent star.
Moreover, the semi-major axis of the planet orbit can be predicted by simple
analytic assumptions in the case of prograde orbits. We find that starless
planets that were initially bound to CW disk stars have mild eccentricities and
tend to remain in the CW disk. However, we speculate that angular momentum
diffusion and scattering with other young stars in the CW disk might bring
starless planets on low-angular momentum orbits. In contrast, planets initially
bound to S-stars are captured by the SMBH on highly eccentric orbits, matching
the orbital properties of the G1 and G2 clouds. Our predictions apply not only
to planets but also to low-mass stars initially bound to the S-stars and
tidally captured by the SMBH.


title:
The Griffiths Phase on Hierarchical Modular Networks with Small-world
  Edges

abstract:
  The Griffiths phase has been proposed to induce a stretched critical regime
that facilitates self-organizing of brain networks for optimal function. This
phase stems from the intrinsic structural heterogeneity of brain networks, such
as the hierarchical modular structure. In this work, we extend this concept to
modified hierarchical networks with small-world connections based on Hanoi
networks. Through extensive simulations, we identify the role of an exponential
distribution of the inter-moduli connectivity probability across hierarchies
determining the emergence of the Griffiths phase. Numerical results and the
complementary spectral analysis on the relevant networks can be helpful for a
deeper understanding of the essential structural characteristics of finite
dimensional networks to support the Griffiths phase.


title: Toward a closed-loop subcutaneous delivery of L-DOPA

abstract:
  L-DOPA has been the gold standard treatment for Parkinson's disease since 50
years. Being the direct biochemical precursor of dopamine, L-DOPA is
effectively converted in the brain, but two major phenomena reduce its
therapeutic action: i) competition with amino acids in the gut wall and in the
blood brain barrier and ii) its fast kinetics (absorption, distribution,
metabolism, and elimination). Continuous administration of L-DOPA, such as
jejunal pumps, have addressed the issue of fast absorption. Considering a
subcutaneous delivery of L-DOPA allows to bypass the gastrointestinal tract and
avoid competition with dietary amino acids. Remains the competition at the
blood barrier between amino acids and L-DOPA, which we address by proposing a
closed-loop controlled, continuous subcutaneous delivery pump. In the
proof-of-concept format, the delivery strategy evaluated on comprehensive model
of L-DOPA kinetics, holds the promise of improving the treatment of late-stage
Parkinson's disease patients.


title: Reduction of Self-heating effect in LDMOS devices

abstract:
  Isotopic purification of group IV elements leads to substantial increase in
thermal conductivity due to reduced scattering of the phonons. Based on this
concept, a simulation study is used to demonstrate the reduction of at least 25
oC in LDMOS average temperature.


title: Derived Hecke algebra and cohomology of arithmetic groups

abstract:
  We describe a graded extension of the usual Hecke algebra: it acts in a
graded fashion on the cohomology of an arithmetic group $\Gamma$. Under
favorable conditions, the cohomology is freely generated in a single degree
over this graded Hecke algebra.
  From this construction we extract an action of certain $p$-adic Galois
cohomology groups on $H^*(\Gamma, \mathbb{Q}_p)$, and formulate the central
conjecture: the motivic $\mathbb{Q}$-lattice inside these Galois cohomology
groups preserves $H^*(\Gamma,\mathbb{Q})$.


title:
Operator-based derivation of phonon modes and characterization of
  correlations for trapped ions at zero and finite temperature

abstract:
  We present a self-contained operator-based approach to derive the spectrum of
trapped ions. This approach provides the complete normal form of the low energy
quadratic Hamiltonian in terms of bosonic phonons, as well as an effective free
particle degree of freedom for each spontaneously broken spatial symmetry. We
demonstrate how this formalism can directly be used to characterize an ion
chain both in the linear and the zigzag regimes. In particular we compute, both
for the ground state and finite temperature states, spatial correlations, heat
capacity and dynamical susceptibility. Last, for the ground state which has
quantum correlations, we analyze the amount of energy reduction compared to an
uncorrelated state with minimum energy, thus highlighting how the system can
lower its energy by correlations.


title: Derived Galois deformation rings

abstract:
  We define a derived version of Mazur's Galois deformation ring. It is a
pro-simplicial ring $\mathcal{R}$ classifying deformations of a fixed Galois
representation to simplicial coefficient rings; its zeroth homotopy group
$\pi_0 \mathcal{R}$ recovers Mazur's deformation ring.
  We give evidence that these rings $\mathcal{R}$ occur in the wild: For
suitable Galois representations, the Langlands program predicts that $\pi_0
\mathcal{R}$ should act on the homology of an arithmetic group. We explain how
the Taylor--Wiles method can be used to upgrade such an action to a graded
action of $\pi_* \mathcal{R}$ on the homology.


title: de Sitter Space is Unstable in Quantum Gravity

abstract:
  Graviton loop corrections to observables in de Sitter space often lead to
infrared divergences. We show that these infrared divergences are resolved by
the spontaneous breaking of de Sitter invariance.


title: Homotopy of Planar Lie Group Equivariant Presheaves

abstract:
  We utilise the theory of crossed simplicial groups to introduce a collection
of local Quillen model structures on the category of simplicial presheaves with
a compact planar Lie group action on a small Grothendieck site. As an
application, we give a characterisation of equivariant cohomology theories on a
site as derived mapping spaces in these model categories.


title:
On the computation of plate assemblies using realistic 3D joint model: a
  non-intrusive approach

abstract:
  Most large engineering structures are described as assemblies of plates and
shells and they are computed as such using adhoc Finite Element packages. In
fact their computation in 3D would be much too costly. In this framework, the
connections between the parts are often modeled by means of simplified tying
models. In order to improve the reliability of such simulations, we propose to
apply a non-intrusive technique so as to virtually substitute the simplified
connectors by a precise 3D nonlinear model, without modifying the global plate
model. Moreover each computation can be conducted on independent optimized
software. After a description of the method, examples are used to analyze its
performance, and to draw some conclusions on the validity and limitation of
both the modeling of junction by rigid connectors and the use of submodeling
techniques for the estimation of the carrying capacity of bolted plates.


title: An Inductive Proof of Bertrand's Postulate

abstract:
  In this paper, we are going to prove a famous problem concerning prime
numbers. Bertrand postulate states that there is always a prime p with n < p <
2n, if n > 1. Bertrand postulate is not a newer one to be proven, in fact,
after his assumption and numerical evidence, Chebyshev was the first person who
proved it. Subsequently, Ramanujan proved it using properties of Gamma
function, and Erd\"os published a simpler proof with the help of Primorial
function, p#. Our approach is unique in the sense that we have used
mathematical induction for finding the upper and lower bounds for the second
Chebyshev function, and they are even stronger than Ramanujan bounds finding
using Gamma function. Otherwise, our approach is similar the way Ramanujan
proved it.


title: Formal Concept Analysis of Rodent Carriers of Zoonotic Disease

abstract:
  The technique of Formal Concept Analysis is applied to a dataset describing
the traits of rodents, with the goal of identifying zoonotic disease
carriers,or those species carrying infections that can spillover to cause human
disease. The concepts identified among these species together provide
rules-of-thumb about the intrinsic biological features of rodents that carry
zoonotic diseases, and offer utility for better targeting field surveillance
efforts in the search for novel disease carriers in the wild.


title: Modeling and Propagating CNNs in a Tree Structure for Visual Tracking

abstract:
  We present an online visual tracking algorithm by managing multiple target
appearance models in a tree structure. The proposed algorithm employs
Convolutional Neural Networks (CNNs) to represent target appearances, where
multiple CNNs collaborate to estimate target states and determine the desirable
paths for online model updates in the tree. By maintaining multiple CNNs in
diverse branches of tree structure, it is convenient to deal with
multi-modality in target appearances and preserve model reliability through
smooth updates along tree paths. Since multiple CNNs share all parameters in
convolutional layers, it takes advantage of multiple models with little extra
cost by saving memory space and avoiding redundant network evaluations. The
final target state is estimated by sampling target candidates around the state
in the previous frame and identifying the best sample in terms of a weighted
average score from a set of active CNNs. Our algorithm illustrates outstanding
performance compared to the state-of-the-art techniques in challenging datasets
such as online tracking benchmark and visual object tracking challenge.


title:
Modified Laplace-Beltrami quantization of natural Hamiltonian systems
  with quadratic constants of motion

abstract:
  It is natural to investigate if the quantization of an integrable or
superintegrable classical Hamiltonian systems is still integrable or
superintegrable. We study here this problem in the case of natural Hamiltonians
with constants of motion quadratic in the momenta. The procedure of
quantization here considered, transforms the Hamiltonian into the
Laplace-Beltrami operator plus a scalar potential. In order to transform the
constants of motion into symmetry operators of the quantum Hamiltonian,
additional scalar potentials, known as quantum corrections, must be introduced,
depending on the Riemannian structure of the manifold. We give here a complete
geometric characterization of the quantum corrections necessary for the case
considered. St\"ackel systems are studied in particular details. Examples in
conformally and non-conformally flat manifolds are given.


title: A Neuro-Fuzzy Model of Time-Varying Decision Boundaries

abstract:
  In a recent study, we reported the results of a new decision making paradigm
in which the participants were asked to balance between their speed and
accuracy to maximize the total reward they achieve during the experiment. The
results of computational modeling provided strong evidence suggesting that the
participants used time-varying decision boundaries. Previous theoretical
studies of the optimal speed-accuracy trade-off suggested that the participants
may learn to use these time-varying boundaries to maximize their average reward
rate. The results in our experiment, however, showed that the participants used
such boundaries even at the beginning of the experiment and without any prior
experience in the task. In this paper, we hypothesize that these boundaries are
the results of using some heuristic rules to make decisions in the task. To
formulate decision making by these heuristic rules as a computational
framework, we use the fuzzy logic theory. Based on this theory, we propose a
new computational framework for decision making in evidence accumulation tasks.
In this framework, there is no explicit decision boundary. Instead, the
subject's desire to stop accumulating evidence and responding at each moment
within a trial and for a given value of the accumulated evidence, is determined
by a set of fuzzy "IF-TEHN rules". We then use the back-propagation method to
derive an algorithm for fitting the fuzzy model to each participant's data. We
then investigate how the difference in the participants' performance in the
experiment is reflected in the difference in the parameters of the fitted model


title:
One-step Patterning of Sub-wavelength Plasmonic Gratings in
  Metal-Polymer Composites

abstract:
  2D and 3D micro/nano fabrication based on two-photon polymerization (TPP) has
emerged as a strong contender for additive manufacturing for wide variety of
applications. In this manuscript we report one step patterning of structurally
stable, subwavelength 2D and 3D gold nanostructures using femto-second laser by
incorporating single photon photoinitiator only in pure and metal precursor
doped polymers. The metal polymer composite nanostructures are written directly
by in-situ reduction of gold precursor within the photoresist using
femto-second laser irradiation. The photo-initiator triggers the reduction of
gold precursor and induces simultaneous polymerization of the photoresist based
on two-photon absorption phenomenon. Diffraction gratings with varied loading
of gold precursors in photoresist have been fabricated and characterized by
measuring their diffraction efficiencies in the infrared region. Minimum line
width of 390 nm has been achieved for 5 wt% gold loaded polymers. Systematic
studies of the effect of laser power, metal precursor loading etc. on the
line-widths have also been performed. These investigations are expected to pave
way for exploration of new material combinations for development of simple
fabrication for fabrication of metal composite functional structures at
significantly low cost and with high-throughput.


title: Meissner-like effect for synthetic gauge field in multimode cavity QED

abstract:
  Previous realizations of synthetic gauge fields for ultracold atoms do not
allow the spatial profile of the field to evolve freely. We propose a scheme
which overcomes this restriction by using the light in a multimode cavity, in
conjunction with Raman coupling, to realize an artificial magnetic field which
acts on a Bose-Einstein condensate of neutral atoms. We describe the evolution
of such a system, and present the results of numerical simulations which show
dynamical coupling between the effective field and the matter on which it acts.
Crucially, the freedom of the spatial profile of the field is sufficient to
realize a close analogue of the Meissner effect, where the magnetic field is
expelled from the superfluid. This back-action of the atoms on the synthetic
field distinguishes the Meissner-like effect described here from the
Hess-Fairbank suppression of rotation in a neutral superfluid observed
elsewhere.

categories: cond-mat.quant-gas cond-mat.supr-con physics.atom-ph quant-ph


title: Minimal number of points on a grid forming patterns of blocks

abstract:
  We consider the minimal number of points on a regular grid on the plane that
generates $n$ blocks of points of exactly length $k$. We illustrate how this is
related to the $n$-queens problem on the toroidal chessboard and show that this
number is upper bounded by $kn/3$ and approaches $kn/4$ as $n\rightarrow\infty$
when $k+1$ is coprime with $6$ or when $k$ is large.


title:
Collapse and revival of the monopole mode of a degenerate Bose gas in an
  isotropic harmonic trap

abstract:
  We study the monopole (breathing) mode of a finite temperature Bose-Einstein
condensate in an isotropic harmonic trap recently developed by Lobser et al.
[Nat.~Phys., \textbf{11}, 1009 (2015)]. We observe a nonexponential collapse of
the amplitude of the condensate oscillation followed by a partial revival. This
behavior is identified as being due to beating between two eigenmodes of the
system, corresponding to in-phase and out-of-phase oscillations of the
condensed and noncondensed fractions of the gas. We perform finite temperature
simulations of the system dynamics using the Zaremba-Nikuni-Griffin methodology
[J.~Low Temp.~Phys., \textbf{116}, 277 (1999)], and find good agreement with
the data, thus confirming the two mode description.


title: Benchmarking State-of-the-Art Deep Learning Software Tools

abstract:
  Deep learning has been shown as a successful machine learning method for a
variety of tasks, and its popularity results in numerous open-source deep
learning software tools. Training a deep network is usually a very
time-consuming process. To address the computational challenge in deep
learning, many tools exploit hardware features such as multi-core CPUs and
many-core GPUs to shorten the training time. However, different tools exhibit
different features and running performance when training different types of
deep networks on different hardware platforms, which makes it difficult for end
users to select an appropriate pair of software and hardware. In this paper, we
aim to make a comparative study of the state-of-the-art GPU-accelerated deep
learning software tools, including Caffe, CNTK, MXNet, TensorFlow, and Torch.
We first benchmark the running performance of these tools with three popular
types of neural networks on two CPU platforms and three GPU platforms. We then
benchmark some distributed versions on multiple GPUs. Our contribution is
two-fold. First, for end users of deep learning tools, our benchmarking results
can serve as a guide to selecting appropriate hardware platforms and software
tools. Second, for software developers of deep learning tools, our in-depth
analysis points out possible future directions to further optimize the running
performance.


title:
Tube Concept for Entangled Stiff Fibers Predicts Their Dynamics in Space
  and Time

abstract:
  We study dynamically crowded solutions of stiff fibers deep in the semidilute
regime, where the motion of a single constituent becomes increasingly confined
to a narrow tube. The spatiotemporal dynamics for wave numbers resolving the
motion in the confining tube becomes accessible in Brownian dynamics
simulations upon employing a geometry-adapted neighbor list. We demonstrate
that in such crowded environments the intermediate scattering function,
characterizing the motion in space and time, can be predicted quantitatively by
simulating a single freely diffusing phantom needle only, yet with very unusual
diffusion coefficients.


title:
Large-scale Collaborative Imaging Genetics Studies of Risk Genetic
  Factors for Alzheimer's Disease Across Multiple Institutions

abstract:
  Genome-wide association studies (GWAS) offer new opportunities to identify
genetic risk factors for Alzheimer's disease (AD). Recently, collaborative
efforts across different institutions emerged that enhance the power of many
existing techniques on individual institution data. However, a major barrier to
collaborative studies of GWAS is that many institutions need to preserve
individual data privacy. To address this challenge, we propose a novel
distributed framework, termed Local Query Model (LQM) to detect risk SNPs for
AD across multiple research institutions. To accelerate the learning process,
we propose a Distributed Enhanced Dual Polytope Projection (D-EDPP) screening
rule to identify irrelevant features and remove them from the optimization. To
the best of our knowledge, this is the first successful run of the
computationally intensive model selection procedure to learn a consistent model
across different institutions without compromising their privacy while ranking
the SNPs that may collectively affect AD. Empirical studies are conducted on
809 subjects with 5.9 million SNP features which are distributed across three
individual institutions. D-EDPP achieved a 66-fold speed-up by effectively
identifying irrelevant features.


title:
A high precision technique to correct for residual atmospheric
  dispersion in high-contrast imaging systems

abstract:
  Direct detection and spectroscopy of exoplanets requires high contrast
imaging. For habitable exoplanets in particular, located at small angular
separation from the host star, it is crucial to employ small inner working
angle (IWA) coronagraphs that efficiently suppress starlight. These
coronagraphs, in turn, require careful control of the wavefront which directly
impacts their performance. For ground-based telescopes, atmospheric refraction
is also an important factor, since it results in a smearing of the PSF, that
can no longer be efficiently suppressed by the coronagraph. Traditionally,
atmospheric refraction is compensated for by an atmospheric dispersion
compensator (ADC). ADC control relies on an a priori model of the atmosphere
whose parameters are solely based on the pointing of the telescope, which can
result in imperfect compensation. For a high contrast instrument like the
Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system, which employs
very small IWA coronagraphs, refraction-induced smearing of the PSF has to be
less than 1 mas in the science band for optimum performance. In this paper, we
present the first on-sky measurement and correction of residual atmospheric
dispersion. Atmospheric dispersion is measured from the science image directly,
using an adaptive grid of artificially introduced speckles as a diagnostic to
feedback to the telescope's ADC. With our current setup, we were able to reduce
the initial residual atmospheric dispersion from 18.8 mas to 4.2 in broadband
light (y- to H-band), and to 1.4 mas in H-band only. This work is particularly
relevant to the upcoming extremely large telescopes (ELTs) that will require
fine control of their ADC to reach their full high contrast imaging potential.


title: Learning Latent Vector Spaces for Product Search

abstract:
  We introduce a novel latent vector space model that jointly learns the latent
representations of words, e-commerce products and a mapping between the two
without the need for explicit annotations. The power of the model lies in its
ability to directly model the discriminative relation between products and a
particular word. We compare our method to existing latent vector space models
(LSI, LDA and word2vec) and evaluate it as a feature in a learning to rank
setting. Our latent vector space model achieves its enhanced performance as it
learns better product representations. Furthermore, the mapping from words to
products and the representations of words benefit directly from the errors
propagated back from the product representations during parameter estimation.
We provide an in-depth analysis of the performance of our model and analyze the
structure of the learned representations.


title: Dynamics of wet granular hexagons

abstract:
  The collective behavior of vibrated hexagonal disks confined in a monolayer
is investigated experimentally. Due to the broken circular symmetry, hexagons
prefer to rotate upon sufficiently strong driving. Due to the formation of
liquid bridges, short-ranged cohesive interactions are introduced upon wetting.
Consequently, a nonequilibrium stationary state with the rotating disks
self-organized in a hexagonal structure arises. The bond length of the
hexagonal structure is slightly smaller than the circumdiameter of a hexagon,
indicating geometric frustration. This investigation provides an example where
the collective behavior of granular matter is tuned by the shape of individual
particles.


title: Combinatorial characterization of upward planarity

abstract:
  We give a combinatorial characterization of upward planar graphs in terms of
upward planar orders, which are special linear extensions of edge posets.


title: CP-Conservation in QCD and why only "invisible" Axions work

abstract:
  Among solutions of the strong CP problem, the "invisible" axion in the narrow
axion window is argued to be the remaining possibility among natural solutions
on the smallness of $\bar{\theta}$. Related to the gravity spoil of global
symmetries, some prospective invisible axions from theory point of view are
discussed. In all these discussions, including the observational possibility,
cosmological constraints must be included.


title: Leibnizian relationalism for general relativistic physics

abstract:
  An ontology of Leibnizian relationalism, consisting in distance relations
among sparse matter points and their change only, is well recognized as a
serious option in the context of classical mechanics. In this paper, we
investigate how this ontology fares when it comes to general relativistic
physics. Using a Humean strategy, we regard the gravitational field as a means
to represent the overall change in the distance relations among point particles
in a way that achieves the best combination of being simple and being
informative.


title: Centralizers in the Group of Interval Exchange Transformations

abstract:
  We study the group of interval exchange transformations. Let $T$ be an
$m$-interval exchange transformation. By the rank of $T$ we mean the dimension
of the $\mathbb{Q}$-vector space spanned by the lengths of the exchanged
subintervals. We prove that if $T$ satisfies Keane's infinite distinct orbit
condition and $\text{rank}(T)>1+\lfloor m/2 \rfloor$ then the only interval
exchange transformations which commute with $T$ are its powers. In the case
that $T$ is a minimal 3-interval exchange transformation, we prove a more
precise result: $T$ has a trivial centralizer in the group of interval exchange
transformations if and only if $T$ satisfies the infinite distinct orbit
condition.


title:
An All-Encompassing Global Convergence Result for Processive Multisite
  Phosphorylation Systems

abstract:
  Phosphorylation, the enzyme-mediated addition of a phosphate group to a
molecule, is a ubiquitous chemical mechanism in biology. Multisite
phosphorylation, the addition of phosphate groups to multiple sites of a single
molecule, may be distributive or processive. Distributive systems can be
bistable, while processive systems were recently shown to be globally stable.
However, this global convergence result was proven only for a specific
mechanism of processive phosphorylation/dephosphorylation (namely, all
catalytic reactions are reversible). Accordingly, we generalize this result to
allow for processive phosphorylation networks in which each reaction may be
irreversible, and also to account for possible product inhibition. We
accomplish this by defining an all-encompassing processive network that
encapsulates all of these schemes, and then appealing to recent results of
Marcondes de Freitas, Wiuf, and Feliu that assert global convergence by way of
monontone systems theory and network/graph reductions (which correspond to
removal of intermediate complexes). Our results form a case study into the
question of when global convergence is preserved when reactions and/or
intermediate complexes are added to or removed from a network.


title:
Complexity of inheritance of $\mathcal{F}$-convexity for restricted
  games induced by minimum partitions

abstract:
  Let $G = (N,E,w)$ be a weighted communication graph (with weight function $w$
on $E$). For every subset $A \subseteq N$, we delete in the subset $E(A)$ of
edges with ends in $A$, all edges of minimum weight in $E(A)$. Then the
connected components of the corresponding induced subgraph constitute a
partition of $A$ that we call $P_{\min}(A)$. For every game $(N, v)$, we define
the $P_{\min}$-restricted game $(N, \bar{v})$ by $\bar{v}(A) = \sum_{F \in
P_{\min}(A)} v(F)$ for all $A \subseteq N$. We prove that we can decide in
polynomial time if there is inheritance of $\mathcal{F}$-convexity from $(N,
v)$ to the $P_{\min}$-restricted game $(N, \bar{v})$ where
$\mathcal{F}$-convexity is obtained by restricting convexity to connected
subsets.


title: Type Inference for Static Compilation of JavaScript (Extended Version)

abstract:
  We present a type system and inference algorithm for a rich subset of
JavaScript equipped with objects, structural subtyping, prototype inheritance,
and first-class methods. The type system supports abstract and recursive
objects, and is expressive enough to accommodate several standard benchmarks
with only minor workarounds. The invariants enforced by the types enable an
ahead-of-time compiler to carry out optimizations typically beyond the reach of
static compilers for dynamic languages. Unlike previous inference techniques
for prototype inheritance, our algorithm uses a combination of lower and upper
bound propagation to infer types and discover type errors in all code,
including uninvoked functions. The inference is expressed in a simple
constraint language, designed to leverage off-the-shelf fixed point solvers. We
prove soundness for both the type system and inference algorithm. An
experimental evaluation showed that the inference is powerful, handling the
aforementioned benchmarks with no manual type annotation, and that the inferred
types enable effective static compilation.


title: Dark Solitons, D-branes and Noncommutative Tachyon Field Theory

abstract:
  In this paper we discuss the boson/vortex duality by mapping the (3+1)D
Gross-Pitaevskii theory into an effective string theory in the presence of
boundaries. Via the effective string theory, we find the Seiberg-Witten map
between the commutative and the noncommutative tachyon field theories, and
consequently identify their soliton solutions with $D$-branes in the effective
string theory. We perform various checks of the duality map and the
identification of soliton solutions. This new insight between the
Gross-Pitaevskii theory and the effective string theory explains the similarity
of these two systems at quantitative level.


title:
Tutorial models of the climate and habitability of Proxima Centauri b: a
  thin atmosphere is sufficient to distribute heat given low stellar flux

abstract:
  Proxima Centauri b, an Earth-size planet in the habitable zone of our nearest
stellar neighbour, has just been discovered. A theoretical framework of
synchronously rotating planets, in which the risk of a runaway greenhouse on
the sunlight side and atmospheric collapse on the reverse side are mutually
ameliorated via heat transport is discussed. This is developed via simple
(tutorial) models of the climate. These show that lower incident stellar flux
means that less heat transport, so less atmospheric mass, is required. The
incident stellar flux at Proxima Centauri b is indeed low, which may help
enhance habitability if it has suffered some atmospheric loss or began with a
low volatile inventory.


title: Quantum Game Application to Spectrum Scarcity Problems

abstract:
  Recent spectrum-sharing research has produced a strategy to address spectrum
scarcity problems. This novel idea, named cognitive radio, considers that
secondary users can opportunistically exploit spectrum holes left temporarily
unused by primary users. This presents a competitive scenario among cognitive
users, making it suitable for game theory treatment. In this work, we show that
the spectrum-sharing benefits of cognitive radio can be increased by designing
a medium access control based on quantum game theory. In this context, we
propose a model to manage spectrum fairly and effectively, based on a
multiple-users multiple-choice quantum minority game. By taking advantage of
quantum entanglement and quantum interference, it is possible to reduce the
probability of collision problems commonly associated with classic algorithms.
Collision avoidance is an essential property for classic and quantum
communications systems. In our model, two different scenarios are considered,
to meet the requirements of different user strategies. The first considers
sensor networks where the rational use of energy is a cornerstone; the second
focuses on installations where the quality of service of the entire network is
a priority.


title:
Degenerations of Ruijsenaars-van Diejen operator and q-Painleve
  equations

abstract:
  It is known that the Painleve VI is obtained by connection preserving
deformation of some linear differential equations, and the Heun equation is
obtained by a specialization of the linear differential equations. We
inverstigate degenerations of the Ruijsenaars-van Diejen difference opearators
and show difference analogues of the Painleve-Heun correspondence.


title:
Shear-Induced Reversibility of quasi-2D Colloids in Presence of Thermal
  Noise

abstract:
  The effects of thermal noise on particle rearrangements in colloidal
suspensions undergoing cyclic shear are experimentally investigated using
particle tracking methods. The experimental model system consists of
polystyrene particles adsorbed at an oil- water interface, in which the
particles exhibit small but non-negligible Brownian motion. We perform
experiments on bidisperse (1 and 1.2 $\mu$m in size) colloidal samples with
area fractions ($\phi$ ) of 0.20 and 0.32. Reversibility of particle
rearrangements are characterized, and we show that unlike dense athermal
systems, reversible clusters are not stable; once a particle enters into a
reversible trajectory, it has a nonzero probability of becoming irreversible in
the following shearing cycle. This probability was previously found to be
approximately zero for an analogous athermal system. We demonstrate that the
stability of reversibility depends both on packing fraction, $\phi$ , and the
shearing amplitude, $\gamma_0$. In addition, we identify hysteresis in the
dynamics of rearrangements for reversible particles, which indicates that such
rearrangements are dissipative. At lower packing fractions, this hysteresis
becomes less prominent, and the dynamics is moved closer to equilibrium by
thermal noise.


title:
Dose rate effects in the radiation damage of the plastic scintillators
  of the CMS Hadron Endcap Calorimeter

abstract:
  We present measurements of the reduction of light output by plastic
scintillators irradiated in the CMS detector during the 8 TeV run of the Large
Hadron Collider and show that they indicate a strong dose rate effect. The
damage for a given dose is larger for lower dose rate exposures. The results
agree with previous measurements of dose rate effects, but are stronger due to
the very low dose rates probed. We show that the scaling with dose rate is
consistent with that expected from diffusion effects.


title:
A conservative local multiscale model reduction technique for Stokes
  flows in heterogeneous perforated domains

abstract:
  In this paper, we present a new multiscale model reduction technique for the
Stokes flows in heterogeneous perforated domains. The challenge in the
numerical simulations of this problem lies in the fact that the solution
contains many multiscale features and requires a very fine mesh to resolve all
details. In order to efficiently compute the solutions, some model reductions
are necessary. To obtain a reduced model, we apply the generalized multiscale
finite element approach, which is a framework allowing systematic construction
of reduced models. Based on this general framework, we will first construct a
local snapshot space, which contains many possible multiscale features of the
solution. Using the snapshot space and a local spectral problem, we identify
dominant modes in the snapshot space and use them as the multiscale basis
functions. Our basis functions are constructed locally with non-overlapping
supports, which enhances the sparsity of the resulting linear system. In order
to enforce the mass conservation, we propose a hybridized technique, and uses a
Lagrange multiplier to achieve mass conservation. We will mathematically
analyze the stability and the convergence of the proposed method. In addition,
we will present some numerical examples to show the performance of the scheme.
We show that, with a few basis functions per coarse region, one can obtain a
solution with excellent accuracy.


title: A hidden classical symmetry of QCD

abstract:
  The classical part of the QCD partition function (the integrand) has,
ignoring irrelevant exact zero modes of the Dirac operator, a local SU(2N_F)
\supset SU(N_F)_L \times SU(N_F)_R \times U(1)_A symmetry which is absent at
the Lagrangian level. This symmetry is broken anomalously and spontaneously.
Effects of spontaneous breaking of chiral symmetry are contained in the
near-zero modes of the Dirac operator. If physics of anomaly is also encoded in
the same near-zero modes, then their truncation on the lattice should recover a
hidden classical SU(2N_F) symmetry in correlators and spectra. This naturally
explains observation on the lattice of a large degeneracy of hadrons, that is
higher than the SU(N_F)_L \times SU(N_F)_R \times U(1)_A chiral symmetry, upon
elimination by hands of the lowest-lying modes of the Dirac operator. We also
discuss an implication of this symmetry for the high temperature QCD.


title: Improved Lower Bounds for Kissing Numbers in Dimensions 25 Through 31

abstract:
  The best previous lower bounds for kissing numbers in dimensions 25 through
31 were constructed using a set $S$ with $|S| = 480$ of minimal vectors of the
Leech Lattice, $\Lambda_{24}$, such that $\langle x, y \rangle \leq 1$ for any
distinct $x, y \in S$. Then, a probabilistic argument based on applying
automorphisms of $\Lambda_{24}$ gives more disjoint sets $S_i$ of minimal
vectors of $\Lambda_{24}$ with the same property. Cohn, Jiao, Kumar, and
Torquato proved that these subsets give kissing configurations in dimensions 25
through 31 of given size linear in the sizes of the subsets. We achieve $|S| =
488$ by applying simulated annealing. We also improve the aforementioned
probabilistic argument in the general case. Finally, we greedily construct even
larger $S_i$'s given our $S$ of size $488$, giving increased lower bounds on
kissing numbers in $\mathbb{R}^{25}$ through $\mathbb{R}^{31}$.


title: On the impact of kinetic mixing in beta functions at two-loop

abstract:
  Kinetic mixing is a fundamental property of models with a gauge symmetry
involving several $\mathrm{U}(1)$ group factors. In this paper, we perform a
numerical study of the impact of kinetic mixing on beta functions at two-loop.
To do so, we use the recently published PyR@TE 2 software to derive the
complete set of RGEs of the SM B-L model at two-loop including kinetic mixing.
We show that it is important to properly account for kinetic mixing as the
evolution of the parameters with the energy scale can change drastically. In
some cases, these modifications can even lead to a different conclusion
regarding the stability of the scalar potential.


title:
BPS/CFT correspondence II: Instantons at crossroads, Moduli and
  Compactness Theorem

abstract:
  Gieseker-Nakajima moduli spaces $M_{k}(n)$ parametrize the charge $k$
noncommutative $U(n)$ instantons on ${\bf R}^{4}$ and framed rank $n$ torsion
free sheaves $\mathcal{E}$ on ${\bf C\bf P}^{2}$ with ${\rm
ch}_{2}({\mathcal{E}}) = k$. They also serve as local models of the moduli
spaces of instantons on general four-manifolds. We study the generalization of
gauge theory in which the four dimensional spacetime is a stratified space $X$
immersed into a Calabi-Yau fourfold $Z$. The local model ${\bf M}_{k}({\vec
n})$ of the corresponding instanton moduli space is the moduli space of charge
$k$ (noncommutative) instantons on origami spacetimes. There, $X$ is modelled
on a union of (up to six) coordinate complex planes ${\bf C}^{2}$ intersecting
in $Z$ modelled on ${\bf C}^{4}$. The instantons are shared by the collection
of four dimensional gauge theories sewn along two dimensional defect surfaces
and defect points. We also define several quiver versions ${\bf M}_{\bf
k}^{\gamma}({\vec{\bf n}})$ of ${\bf M}_{k}({\vec n})$, motivated by the
considerations of sewn gauge theories on orbifolds ${\bf C}^{4}/{\Gamma}$.
  The geometry of the spaces ${\bf M}_{\bf k}^{\gamma}({\vec{\bf n}})$, more
specifically the compactness of the set of torus-fixed points, for various
tori, underlies the non-perturbative Dyson-Schwinger identities recently found
to be satisfied by the correlation functions of $qq$-characters viewed as local
gauge invariant operators in the ${\mathcal{N}}=2$ quiver gauge theories.
  The cohomological and K-theoretic operations defined using ${\bf M}_{k}({\vec
n})$ and their quiver versions as correspondences provide the geometric
counterpart of the $qq$-characters, line and surface defects.


title: Quasi-optical theory of microwave plasma heating in open magnetic trap

abstract:
  Microwave heating of a high-temperature plasma confined in a large-scale open
magnetic trap, including all important wave effects like diffraction,
absorption, dispersion and wave beam aberrations, is described for the first
time within the first-principle technique based on consistent Maxwell's
equations. With this purpose, the quasi-optical approach is generalized over
weakly inhomogeneous gyrotrotropic media with resonant absorption and spatial
dispersion, and a new form of the integral quasi-optical equation is proposed.
An effective numerical technique for this equation's solution is developed and
realized in a new code QOOT, which is verified with the simulations of
realistic electron cyclotron heating scenarios at the Gas Dynamic Trap at the
Budker Institute of Nuclear Physics (Novosibirsk, Russia).


title: PyR@TE 2: A Python tool for computing RGEs at two-loop

abstract:
  Renormalization group equations are an essential tool for the description of
theories accross different energy scales. Even though their expressions at
two-loop for an arbitrary gauge field theory have been known for more than
thirty years, deriving the full set of equations for a given model by hand is
very challenging and prone to errors. To tackle this issue, we have introduced
in [1] a Python tool called PyR@TE; Python Renormalization group equations @
Two-loop for Everyone. With PyR@TE, it is easy to implement a given Lagrangian
and derive the complete set of two-loop RGEs for all the parameters of the
theory. In this paper, we present the new version of this code, PyR@TE 2, which
brings many new features and in particular it incorporates kinetic mixing when
several $\mathrm{U}(1)$ gauge groups are involved. In addition, the group
theory part has been greatly improved as we introduced a new Python module
dubbed PyLie that deals with all the group theoretical aspects required for the
calculation of the RGEs as well as providing very useful model building
capabilities. This allows the use of any irreducible representation of the
$\mathrm{SU}(n)$, $\mathrm{SO}(2n)$ and $\mathrm{SO(2n+1)}$ groups. %
Furthermore, it is now possible to implement terms in the Lagrangian involving
fields which can be contracted into gauge singlets in more than one way. As a
byproduct, results for a popular model (SM+complex triplet) for which, to our
knowledge, the complete set of two-loop RGEs has not been calculated before are
presented in this paper. Finally, the two-loop RGEs for the anomalous dimension
of the scalar and fermion fields have been implemented as well. It is now
possible to export the coupled system of beta functions into a numerical C++
function, leading to a consequent speed up in solving them.


title: Quantum Mechanics in the Infrared

abstract:
  This paper presents an algebraic formulation of the renormalization group
flow in quantum mechanics on flat target spaces. For any interacting quantum
mechanical theory, the fixed point of this flow is a theory of classical
probability, not a different effective quantum mechanics. Each energy
eigenstate of the UV Hamiltonian flows to a probability distribution whose
entropy is a natural diagnostic of quantum ergodicity of the original state.
These conclusions are supported by various examples worked out in some detail.


title:
Regularity Structure, Vorticity Layer and Convergence Rates of Inviscid
  Limit of Free Surface Navier-Stokes Equations with or without Surface Tension

abstract:
  In this paper, we study the inviscid limit of the free surface incompressible
Navier-Stokes equations with or without surface tension. By delicate estimates,
we prove the weak boundary layer of the velocity of the free surface
Navier-Stokes equations and the existence of strong or weak vorticity layer for
different conditions. When the limit of the difference between the initial
Navier-Stokes vorticity and the initial Euler vorticity is nonzero, or the
tangential projection on the free surface of the Euler strain tensor
multiplying by normal vector is nonzero, there exists a strong vorticity layer.
Otherwise, the vorticity layer is weak. We estimate convergence rates of
tangential derivatives and the first order standard normal derivative in energy
norms, we show that not only tangential derivatives and standard normal
derivative have different convergence rates, but also their convergence rates
are different for different Euler boundary data. Moreover, we determine
regularity structure of the free surface Navier-Stokes solutions with or
without surface tension, surface tension changes regularity structure of the
solutions.


title:
Multiband electronic transport in $\alpha$-Yb$_{1-x}$Sr$_{x}$AlB$_{4}$
  [x = 0, 0.19(3)] single crystals

abstract:
  We report on the evidence for the multiband electronic transport in
$\alpha$-YbAlB$_{4}$ and $\alpha$-Yb$_{0.81(2)}$Sr$_{0.19(3)}$AlB$_{4}$.
Multiband transport reveals itself below 10 K in both compounds via Hall effect
measurements, whereas anisotropic magnetic ground state sets in below 3 K in
$\alpha$-Yb$_{0.81(2)}$Sr$_{0.19(3)}$AlB$_{4}$. Our results show that Sr$^{2+}$
substitution enhances conductivity, but does not change the quasiparticle mass
of bands induced by heavy fermion hybridization.


title:
Solar Abundances of Rock Forming Elements, Extreme Oxygen and Hydrogen
  in a Young Polluted White Dwarf

abstract:
  The Teff = 20,800 K white dwarf WD 1536+520 is shown to have broadly solar
abundances of the major rock forming elements O, Mg, Al, Si, Ca, and Fe,
together with a strong relative depletion in the volatile elements C and S. In
addition to the highest metal abundances observed to date, including log(O/He)
= -3.4, the helium-dominated atmosphere has an exceptional hydrogen abundance
at log(H/He) = -1.7. Within the uncertainties, the metal-to-metal ratios are
consistent with the accretion of an H2O-rich and rocky parent body, an
interpretation supported by the anomalously high trace hydrogen. The mixed
atmosphere yields unusually short diffusion timescales for a helium atmosphere
white dwarf, of no more than a few hundred yr, and equivalent to those in a
much cooler, hydrogen-rich star. The overall heavy element abundances of the
disrupted parent body deviate modestly from a bulk Earth pattern, and suggest
the deposition of some core-like material. The total inferred accretion rate is
4.2e9 g/s, and at least 4 times higher than any white dwarf with a comparable
diffusion timescale. Notably, when accretion is exhausted in this system, both
metals and hydrogen will become undetectable within roughly 300 Myr, thus
supporting a scenario where the trace hydrogen is related to the ongoing
accretion of planetary debris.


title: Little String Origin of Surface Defects

abstract:
  We derive the codimension-two defects of 4d $\mathcal{N} = 4$ Super
Yang-Mills (SYM) theory from the (2, 0) little string. The origin of the little
string is type IIB theory compactified on an ADE singularity. The defects are
D-branes wrapping the 2-cycles of the singularity. We use this construction to
make contact with the description of SYM defects due to Gukov and Witten
[arXiv:hep-th/0612073]. Furthermore, we derive from a geometric perspective the
complete nilpotent orbit classification of codimension-two defects, and the
connection to ADE-type Toda CFT. The only data needed to specify the defects is
a set of weights of the algebra obeying certain constraints, which we give
explicitly. We highlight the differences between the defect classification in
the little string theory and its (2, 0) CFT limit.


title:
The Rest-Frame Optical Spectroscopic Properties of Ly$\alpha$-Emitters
  at $z\sim2.5$: The Physical Origins of Strong Ly$\alpha$ Emission

abstract:
  We present rest-frame optical spectra of 60 faint ($R_{AB}\sim 27$; $L\sim0.1
L_*$) Ly$\alpha$-selected galaxies (LAEs) at $z\approx2.56$. The average LAE is
consistent with the extreme low-metallicity end of the continuum-selected
galaxy distribution at $z\approx2-3$. In particular, the LAEs have extremely
high [OIII] $\lambda$5008/H$\beta$ ratios (log([OIII]/H$\beta$) $\sim$ 0.8) and
low [NII] $\lambda$6585/H$\alpha$ ratios (log([NII]/H$\alpha$) $<-1.15$). Using
the [OIII] $\lambda$4364 auroral line, we find that the star-forming regions in
faint LAEs are characterized by high electron temperatures
($T_e\approx1.8\times10^4$K), low oxygen abundances (12 + log(O/H) $\approx$
8.04, $Z_{neb}\approx0.22Z_\odot$), and high excitations with respect to more
luminous galaxies. Our faintest LAEs have line ratios consistent with even
lower metallicities, including six with 12 + log(O/H) $\approx$ 6.9$-$7.4
($Z_{neb}\approx0.02-0.05Z_\odot$). We interpret these observations in light of
new models of stellar evolution (including binary interactions). We find that
strong, hard ionizing continua are required to reproduce our observed line
ratios, suggesting that faint galaxies are efficient producers of ionizing
photons and important analogs of reionization-era galaxies. Furthermore, we
investigate physical trends accompanying Ly$\alpha$ emission across the largest
current sample of combined Ly$\alpha$ and rest-optical galaxy spectroscopy,
including 60 faint LAEs and 368 more luminous galaxies at similar redshifts. We
find that Ly$\alpha$ emission is strongly correlated with nebular excitation
and ionization and weakly correlated with dust attenuation, suggesting that
metallicity plays a strong role in determining the observed properties of these
galaxies by modulating their stellar spectra, nebular excitation, and dust
content.


title: New Halo White Dwarf Candidates in the Sloan Digital Sky Survey

abstract:
  We present optical spectroscopy and near-infrared photometry of 57 faint ($g=
19-22$) high proper motion white dwarfs identified through repeat imaging of
$\approx3100$ square degrees of the Sloan Digital Sky Survey footprint by Munn
et al. (2014). We use $ugriz$ and $JH$ photometry to perform a model atmosphere
analysis, and identify ten ultracool white dwarfs with $T_{\rm eff}<4000$ K,
including the coolest pure H atmosphere white dwarf currently known,
J1657+2638, with $T_{\rm eff}= 3550 \pm 100$K. The majority of the objects with
cooling ages larger than 9 Gyr display thick disc kinematics and constrain the
age of the thick disc to $\geq11$ Gyr. There are four white dwarfs in our
sample with large tangential velocities ($v_{tan} > 120$ km $s^{-1}$) and UVW
velocities that are more consistent with the halo than the Galactic disc. For
typical $0.6 M_{\odot}$ white dwarfs, the cooling ages for these halo
candidates range from 2.3 to 8.5 Gyr. However, the total main-sequence + white
dwarf cooling ages of these stars would be consistent with the Galactic halo if
they are slightly undermassive. Given the magnitude limits of the current large
scale surveys, many of the coolest and oldest white dwarfs remain undiscovered
in the solar neighborhood, but upcoming surveys such as GAIA and the Large
Synoptic Survey Telescope (LSST) should find many of these elusive thick disc
and halo white dwarfs.


title:
Challenges and opportunities for heavy scalar searches in the $t\bar t$
  channel at the LHC

abstract:
  Heavy scalar and pseudoscalar resonance searches through the $gg\rightarrow
S\rightarrow t\bar t$ process are challenging due to the peculiar behavior of
the large interference effects with the standard model $t\bar t$ background.
Such effects generate non-trivial lineshapes from additional relative phases
between the signal and background amplitudes. We provide the analytic
expressions for the differential cross sections to understand the interference
effects in the heavy scalar signal lineshapes. We extend our study to the case
of CP-violation and further consider the effect of bottom quarks in the
production and decay processes. We also evaluate the contributions from
additional particles to the gluon fusion production process, such as stops and
vector-like quarks, that could lead to significant changes in the behavior of
the signal lineshapes. Taking into account the large interference effects, we
perform lineshape searches at the LHC and discuss the importance of the
systematic uncertainties and smearing effects. We present projected
sensitivities for two LHC performance scenarios to probe the $gg\rightarrow S
\rightarrow t\bar t$ channel in various models.


title: Probing the hardest branching of jets in heavy ion collisions

abstract:
  We present the first calculation of the momentum sharing and angular
separation distributions between the leading subjets inside a reconstructed jet
in heavy ion collisions. These observables are directly sensitive to the
hardest branching in the process of jet formation and are, therefore, ideal for
studying the early stage of the in-medium parton shower evolution. The
modification of the momentum sharing and angular separation distributions in
lead-lead relative to proton-proton collisions is evaluated using the
leading-order medium-induced splitting functions obtained in the framework of
soft-collinear effective theory with Glauber gluon interactions. Qualitative
and in most cases quantitative agreement between theory and preliminary CMS
measurements suggests that the parton shower in heavy ion collisions can be
dramatically modified early in the branching history. We propose a new
measurement which will illuminate the angular distribution of the hardest
branching within jets in heavy ion collisions.


title:
X-ray and infrared diagnostics of nearby active galactic nuclei with
  MAXI and AKARI

abstract:
  Nearby active galactic nuclei were diagnosed in the X-ray and mid-to-far
infrared wavelengths, with Monitor of All-sky X-ray Image (MAXI) and the
Japanese infrared observatory AKARI, respectively. Among the X-ray sources
listed in the second release of the MAXI all-sky X-ray source catalog, 100 ones
are currently identified as a non-blazar-type active galactic nucleus. These
include 95 Seyfert galaxies and 5 quasars, and they are composed of 73 type-1
and 27 type-2 objects. The AKARI all-sky survey point source catalog was
searched for their mid- and far-infrared counterparts at 9, 18, and 90 $\mu$m.
As a result, 69 Seyfert galaxies in the MAXI catalog (48 type-1 and 21 type-2
ones) were found to be detected with AKARI. The X-ray (3-4 keV and 4-10 keV)
and infrared luminosities of these objects were investigated, together with
their color information. Adopting the canonical photon index, $\Gamma = 1.9$,
of the intrinsic X-ray spectrum of the Seyfert galaxies, the X-ray hardness
ratio between the 3-4 and 4-10 keV ranges derived with MAXI was roughly
converted into the absorption column density. After the X-ray luminosity was
corrected for absorption from the estimated column density, the well-known
X-ray-to-infrared luminosity correlation was confirmed at least in the
Compton-thin regime. In contrast, NGC 1365, only one Compton-thick object in
the MAXI catalog, was found to deviate from the correlation toward a
significantly lower X-ray luminosity by nearly an order of magnitude. It was
verified that the relation between the X-ray hardness below 10 keV and
X-ray-to-infrared color acts as an effective tool to pick up Compton-thick
objects. The difference in the infrared colors between the type-1 and type-2
Seyfert galaxies and its physical implication on the classification and
unification of active galactic nuclei were briefly discussed.


title:
The Survey of Centaurus A's Baryonic Structures (SCABS). I. Survey
  Description and Initial Source Catalogues

abstract:
  We present new, wide-field, optical ($u'g'r'i'z'$) Dark Energy Camera
observations covering $\sim21\,{\rm deg}^2$ centred on the nearby giant
elliptical galaxy NGC5128 called "The Survey of Centaurus A's Baryonic
Structures" (SCABS). The data reduction and analysis procedures are described
including initial source detection, photometric and astrometric calibration,
image stacking, and point-spread function modelling. We estimate 50 and 90
percent, field-dependent, point-source completeness limits of at least
$u'=24.08$ and $23.62$ mag (AB), $g'=22.67$ and $22.27$ mag, $r'=22.46$ and
$22.00$ mag, $i'=22.05$ and $21.63$ mag, and $z'=21.71$ and $21.34$ mag. Deeper
imaging in the $u'$-, $i'$- and $z'$-bands provide the fainter limits for the
inner $\sim3\,{\rm deg}^2$ of the survey, and we find very stable photometric
sensitivity across the entire field of view. Source catalogues are released in
all filters including spatial, photometric, and morphological information for a
total of $\sim5\times10^5-1.5\times10^6$ detected sources (filter-dependent).
We finish with a brief discussion of potential science applications for the
data including, but not limited to, upcoming works by the SCABS team.


title:
The chaotic four-body problem in Newtonian gravity I: Identical
  point-particles

abstract:
  In this paper, we study the chaotic four-body problem in Newtonian gravity.
Assuming point particles and total encounter energies $\le$ 0, the problem has
three possible outcomes. We describe each outcome as a series of discrete
transformations in energy space, using the diagrams first presented in Leigh \&
Geller (2012; see the Appendix). Furthermore, we develop a formalism for
calculating probabilities for these outcomes to occur, expressed using the
density of escape configurations per unit energy, and based on the Monaghan
description originally developed for the three-body problem. We compare this
analytic formalism to results from a series of binary-binary encounters with
identical point particles, simulated using the \texttt{FEWBODY} code. Each of
our three encounter outcomes produces a unique velocity distribution for the
escaping star(s). Thus, these distributions can potentially be used to
constrain the origins of dynamically-formed populations, via a direct
comparison between the predicted and observed velocity distributions. Finally,
we show that, for encounters that form stable triples, the simulated single
star escape velocity distributions are the same as for the three-body problem.
This is also the case for the other two encounter outcomes, but only at low
virial ratios. This suggests that single and binary stars processed via
single-binary and binary-binary encounters in dense star clusters should have a
unique velocity distribution relative to the underlying Maxwellian distribution
(provided the relaxation time is sufficiently long), which can be calculated
analytically.


title: Many-body delocalization with random vector potentials

abstract:
  We study the ergodic properties of excited states in a model of interacting
fermions in quasi-one-dimensional chains subjected to a random vector
potential. In the noninteracting limit, we show that arbitrarily small values
of this complex off-diagonal disorder trigger localization for the whole
spectrum; the divergence of the localization length in the single-particle
basis is characterized by a critical exponent $\nu$ which depends on the energy
density being investigated. When short-range interactions are included, the
localization is lost, and the system is ergodic regardless of the magnitude of
disorder in finite chains. Our numerical results suggest a delocalization
scheme for arbitrary small values of interactions. This finding indicates that
the standard scenario of the many-body localization cannot be obtained in a
model with random gauge fields.


title:
The Survey of Centaurus A's Baryonic Structures (SCABS). II. The
  Extended Globular Cluster System of NGC5128 and its Nearby Environment

abstract:
  Wide-field $u'g'r'i'z'$ Dark Energy Camera observations centred on the giant
elliptical galaxy NGC5128 covering $\sim21deg^2$ are used to compile a new
catalogue of $\sim3200$ globular clusters (GCs). We report 2404 new candidates,
including the vast majority within $\sim140$kpc of NGC5128. We find evidence
for a transition at a galactocentric radius of $R_{\rm gc}\approx55$kpc from
GCs intrinsic to NGC5128 to those likely to have been accreted from dwarf
galaxies or that may transition to the intra-group medium of the Centaurus A
galaxy group. We fit power-law surface number density profiles of the form
$\Sigma_{N, R_{\rm gc}}\propto R_{\rm gc}^\Gamma$ and find that inside the
transition radius, the red GCs are more centrally concentrated than the blue,
with $\Gamma_{\rm inner,red}\approx-1.78$ and $\Gamma_{\rm
inner,blue}\approx-1.40$. Outside this region both profiles flatten, more
dramatically for the red GCs ($\Gamma_{\rm outer,red}\approx-0.33$) compared to
the blue ($\Gamma_{\rm outer,blue}\approx-0.61$), although the former is more
likely to suffer contamination by background sources. The median
$(g'\!-\!z')_0\!=\!1.27$mag colour of the inner red population is consistent
with arising from the amalgamation of two giant galaxies each less luminous
than present-day NGC5128. Both in- and out-ward of the transition radius, we
find the fraction of blue GCs to dominate over the red GCs, indicating a lively
history of minor-mergers. Assuming the blue GCs to originate primarily in dwarf
galaxies, we model the population required to explain them, while remaining
consistent with NGC5128's present-day spheroid luminosity. We find that several
dozen dwarfs of luminosities $L_{dw,V}\simeq10^{6-9.3}L_{V,\odot}$, following a
Schechter luminosity function with a faint-end slope of
$-1.50\leq\alpha\leq-1.25$ is favoured, many of which may have already been
disrupted in NGC5128's tidal field.


title:
The angular power spectrum of the diffuse gamma-ray emission as measured
  by the Fermi Large Area Telescope and constraints on its Dark Matter
  interpretation

abstract:
  The isotropic gamma-ray background arises from the contribution of unresolved
sources, including members of confirmed source classes and proposed gamma-ray
emitters such as the radiation induced by dark matter annihilation and decay.
Clues about the properties of the contributing sources are imprinted in the
anisotropy characteristics of the gamma-ray background. We use 81 months of
Pass 7 Reprocessed data from the Fermi Large Area Telescope to perform a
measurement of the anisotropy angular power spectrum of the gamma-ray
background. We analyze energies between 0.5 and 500 GeV, extending the range
considered in the previous measurement based on 22 months of data. We also
compute, for the first time, the cross-correlation angular power spectrum
between different energy bins. We find that the derived angular spectra are
compatible with being Poissonian, i.e. constant in multipole. Moreover, the
energy dependence of the anisotropy suggests that the signal is due to two
populations of sources, contributing, respectively, below and above 2 GeV.
Finally, using data from state-of-the-art numerical simulations to model the
dark matter distribution, we constrain the contribution from dark matter
annihilation and decay in Galactic and extragalactic structures to the measured
anisotropy. These constraints are competitive with those that can be derived
from the average intensity of the isotropic gamma-ray background. Data are
available at https://www-glast.stanford.edu/pub_data/552.


title:
Asteroseismology of the Hyades with K2: first detection of main-sequence
  solar-like oscillations in an open cluster

abstract:
  The Hyades open cluster was targeted during Campaign 4 (C4) of the NASA K2
mission, and short-cadence data were collected on a number of cool
main-sequence stars. Here, we report results on two F-type stars that show
detectable oscillations of a quality that allows asteroseismic analyses to be
performed. These are the first ever detections of solar-like oscillations in
main-sequence stars in an open cluster.


title:
The peculiar dipping events in the disk-bearing young-stellar object
  EPIC 204278916

abstract:
  EPIC 204278916 has been serendipitously discovered from its K2 light curve
which displays irregular dimmings of up to 65% for ~25 consecutive days out of
78.8 days of observations. For the remaining duration of the observations, the
variability is highly periodic and attributed to stellar rotation. The star is
a young, low-mass (M-type) pre-main-sequence star with clear evidence of a
resolved tilted disk from ALMA observations. We examine the K2 light curve in
detail and hypothesise that the irregular dimmings are caused by either a
warped inner-disk edge or transiting cometary-like objects in either circular
or eccentric orbits. The explanations discussed here are particularly relevant
for other recently discovered young objects with similar absorption dips.


title:
Asteroseismic properties of solar-type stars observed with the NASA K2
  mission: results from Campaigns 1-3 and prospects for future observations

abstract:
  We present an asteroseismic analysis of 33 solar-type stars observed in short
cadence during Campaigns (C) 1-3 of the NASA K2 mission. We were able to
extract both average seismic parameters and individual mode frequencies for
stars with dominant frequencies up to ~3300{\mu}Hz, and we find that data for
some targets are good enough to allow for a measurement of the rotational
splitting. Modelling of the extracted parameters is performed by using
grid-based methods using average parameters and individual frequencies together
with spectroscopic parameters. For the target selection in C3, stars were
chosen as in C1 and C2 to cover a wide range in parameter space to better
understand the performance and noise characteristics. For C3 we still detected
oscillations in 73% of the observed stars that we proposed. Future K2 campaigns
hold great promise for the study of nearby clusters and the chemical evolution
and age-metallicity relation of nearby field stars in the solar neighbourhood.
We expect oscillations to be detected in ~388 short-cadence targets if the K2
mission continues until C18, which will greatly complement the ~500 detections
of solar-like oscillations made for short-cadence targets during the nominal
Kepler mission. For ~30-40 of these, including several members of the Hyades
open cluster, we furthermore expect that inference from interferometry should
be possible.


title: Radial Variation in the Stellar Mass Functions of Star Clusters

abstract:
  A number of recent observational studies of Galactic globular clusters have
measured the variation in the slope of a cluster's stellar mass function
$\alpha$ with clustercentric distance $r$. In order to gather a deeper
understanding of the information contained in such observations, we have
explored the evolution of $\alpha(r)$ for star clusters with a variety of
initial conditions using a large suite of $N$-body simulations. We have
specifically studied how the time evolution of $\alpha(r)$ is affected by
initial size, mass, binary fraction, primordial mass segregation, black hole
retention, an external tidal field, and the initial mass function itself.
Previous studies have shown that the evolution of $\alpha_G$ is closely related
to the amount of mass loss suffered by a cluster. Hence for each simulation we
have also followed the evolution of the slope of the cluster's global stellar
mass function, $\alpha_G$, and have shown that clusters follow a well-defined
track in the $\alpha_G$-$d\alpha(r)/d(ln(r/r_m))$ plane. The location of a
cluster on the $\alpha_G-d\alpha(r)/d(ln(r/r_m))$ plane can therefore constrain
its dynamical history and, in particular, constrain possible variations in the
stellar initial mass function. The $\alpha_G$-$d\alpha(r)/d(ln(r/r_m))$ plane
thus serves as a key tool for fully exploiting the information contained in
wide field studies of cluster stellar mass functions.


title: Exact microstate counting for dyonic black holes in AdS4

abstract:
  We present a counting of microstates of a class of dyonic BPS black holes in
AdS$_4$ which precisely reproduces their Bekenstein-Hawking entropy. The
counting is performed in the dual boundary description, that provides a
non-perturbative definition of quantum gravity, in terms of a twisted and
mass-deformed ABJM theory. We evaluate its twisted index and propose an
extremization principle to extract the entropy, which reproduces the attractor
mechanism in gauged supergravity.


title:
Constraining Flavor Changing Interactions from LHC Run-2 Dilepton Bounds
  with Vector Mediators

abstract:
  Within the context of vector mediators, is a new signal observed in flavor
changing interactions, particularly in the neutral mesons systems
$K^{0}-\bar{K}^{0}$, $D^{0}-\bar{D}^{0}$ and $B^0-\bar{B^0}$, consistent with
dilepton resonance searches at the LHC? In the attempt to address this very
simple question, we discuss the complementarity between flavor changing neutral
current (FCNC) and dilepton resonance searches at the LHC run 2 at $13$TeV with
$3.2\, {\rm fb^{-1}}$ of integrated luminosity, in the context of vector
mediators at tree level. Vector mediators, are often studied in the flavor
changing framework, specially in the light of the recent LHCb anomaly observed
at the rare B decay. However, the existence of stringent dilepton bound
severely constrains flavor changing interactions, due to restrictive limits on
the $Z^{\prime}$ mass. We discuss this interplay explicitly in the well
motivated framework of a 3-3-1 scheme, where fermions and scalars are arranged
in the fundamental representation of the weak SU(3) gauge group. Due to the
paucity of relevant parameters, we conclude dilepton data leave little room for
a possible new physics signal stemming from these systems, unless a very
peculiar texture parametrization is used in the diagonalization of the CKM
matrix. In other words, if a signal is observed in such flavor changing
interactions, it is unlikely comes from a 3-3-1 model.


title: Direct Detection of Dark Matter Bound to the Earth

abstract:
  We study the properties and direct detection prospects of an as of yet
neglected population of dark matter (DM) particles moving in orbits
gravitationally bound to the Earth. This DM population is expected to form via
scattering by nuclei in the Earth's interior. We compute fluxes and nuclear
recoil energy spectra expected at direct detection experiments for the new DM
population considering detectors with and without directional sensitivity, and
different types of target materials and DM-nucleon interactions. DM particles
bound to the Earth manifest as a prominent rise in the low-energy part of the
observed nuclear recoil energy spectrum. Ultra-low threshold energies of about
1 eV are needed to resolve this effect. Its shape is independent of the
DM-nucleus scattering cross-section normalisation.


title:
Characterizing stellar halo populations II: The age gradient in blue
  horizontal-branch stars

abstract:
  The distribution of Milky Way halo blue horizontal-branch (BHB) stars is
examined using action-based extended distribution functions (EDFs) that
describe the locations of stars in phase space, metallicity, and age. The
parameters of the EDFs are fitted using stars observed in the Sloan Extension
for Galactic Understanding and Exploration-II (SEGUE-II) survey that trace the
phase-space kinematics and chemistry out to ~70 kpc. A maximum a posteriori
probability (MAP) estimate method and a Markov Chain Monte Carlo method are
applied, taking into account the selection function in positions, distance, and
metallicity for the survey. The best-fit EDF declines with actions less steeply
at actions characteristic of the inner halo than at the larger actions
characteristic of the outer halo, and older ages are found at smaller actions
than at larger actions. In real space, the radial density profile steepens
smoothly from -2 at ~2 kpc to -4 in the outer halo, with an axis ratio ~0.7
throughout. There is no indication for rotation in the BHBs, although this is
highly uncertain. A moderate level of radial anisotropy is detected, with
$\beta_s$ varying from isotropic to between ~0.1 and ~0.3 in the outer halo
depending on latitude. The BHB data are consistent with an age gradient of
-0.03 Gyr kpc$^{-1}$, with some uncertainty in the distribution of the larger
ages. These results are consistent with a scenario in which older, larger
systems contribute to the inner halo, whilst the outer halo is primarily
comprised of younger, smaller systems.


title: One Loop Tests of Supersymmetric Higher Spin $AdS_4/CFT_3$

abstract:
  We compute one loop free energy for D=4 Vasiliev higher spin gravities based
on Konstein-Vasiliev algebras hu(m;n|4), ho(m;n|4) or husp(m;n|4) and subject
to higher spin preserving boundary conditions, which are conjectured to be dual
to the U(N), O(N) or USp(N) singlet sectors, respectively, of free CFTs on the
boundary of $AdS_4$. Ordinary supersymmetric higher spin theories appear as
special cases of Konstein-Vasiliev theories, when the corresponding higher spin
algebra contains $OSp({\cal N}|4)$ as subalgebra. In $AdS_4$ with $S^3$
boundary, we use a modified spectral zeta function method, which avoids the
ambiguity arising from summing over infinite number of spins. We find that the
contribution of the infinite tower of bulk fermions vanishes. As a result, the
free energy is the sum of those which arise in type A and type B models with
internal symmetries, the known mismatch between the bulk and boundary free
energies for type B model persists, and ordinary supersymmetric higher spin
theories exhibit the mismatch as well. The only models that have a match are
type A models with internal symmetries, corresponding to $n=0$. The matching
requires identification of the inverse Newton's constant $G_N^{-1}$ with $N$
plus a proper integer as was found previously for special cases. In $AdS_4$
with $S^1\times S^2$ boundary, the bulk one loop free energies match those of
the dual free CFTs for arbitrary $m$ and $n$. We also show that a
supersymmetric double-trace deformation of free CFT based on OSp(1|4) does not
contribute to the ${\cal O}(N^0)$ free energy, as expected from the bulk.


title: Consequences and applications of the completeness of Hardy's nonlocality

abstract:
  Logical nonlocality is completely characterized by Hardy's "paradox" in
(2,2,l) and (2,k,2) scenarios. We consider a variety of consequences and
applications of this fact. (i) Polynomial algorithms may be given for deciding
logical nonlocality in these scenarios. (ii) Bell states are the only entangled
two-qubit states which are not logically nonlocal under projective
measurements. (iii) It is possible to witness Hardy nonlocality with certainty
in a simple tripartite quantum system. (iv) Noncommutativity of observables is
necessary and sufficient for enabling logical nonlocality.


title:
The TeV emission of Ap Librae: a hadronic interpretation and prospects
  for CTA

abstract:
  Ap Librae is one out of a handful of low-frequency peaked blazars to be
detected at TeV $\gamma$-rays and the only one with an identified X-ray jet.
Combined observations of Fermi-LAT at high energies (HE) and of H.E.S.S at very
high energies (VHE) revealed a striking spectral property of Ap Librae; the
presence of a broad high-energy component that extends more than nine orders of
magnitude in energy and is, therefore, hard to be explained by the usual
single-zone synchrotron self-Compton model. We show that the superposition of
different emission components related to photohadronic interactions can explain
the $\gamma$-ray emission of Ap Librae without invoking external radiation
fields. We present two indicative model fits to the spectral energy
distribution of Ap Librae where the VHE emission is assumed to originate from a
compact, sub-pc scale region of the jet. A robust prediction of our model is
VHE flux variability on timescales similar to those observed at X-rays and HE
$\gamma$-rays, which can be further used to distinguish between a sub-pc or kpc
scale origin of the TeV emission. We thus calculate the expected variability
signatures at X-rays, HE and VHE $\gamma$-rays and show that quasi-simultaneous
flares are expected, with larger amplitude flares appearing at $\gamma$-rays.
We assess the detectability of VHE variability from Ap Librae with CTA, next
generation of IACTs. We show that $\sim$hr timescale variability at
$E_{\gamma}>0.1$ TeV could be detectable at high significance with shorter
exposure times than current Cherenkov telescopes.


title: Poincar\'e chaos and unpredictable functions

abstract:
  The results of this study are continuation of the research of Poincar\'e
chaos initiated in papers (Akhmet M, Fen MO. Commun Nonlinear Sci Numer Simulat
2016;40:1-5; Akhmet M, Fen MO. Turk J Math, doi:10.3906/mat-1603-51, accepted).
We focus on the construction of an unpredictable function, continuous on the
real axis. As auxiliary results, unpredictable orbits for the symbolic dynamics
and the logistic map are obtained. By shaping the unpredictable function as
well as Poisson function we have performed the first step in the development of
the theory of unpredictable solutions for differential and discrete equations.
The results are preliminary ones for deep analysis of chaos existence in
differential and hybrid systems. Illustrative examples concerning unpredictable
solutions of differential equations are provided.


title:
Coherent dynamics of V-type systems driven by time-dependent incoherent
  radiation

abstract:
  Light induced processes in nature occur by irradiation with slowly turned-on
incoherent light. The general case of time-dependent incoherent excitation is
solved here analytically for V-type systems using a newly developed master
equation method. Clear evidence emerges for the disappearance of radiatively
induced coherence as turn-on times of the radiation exceed characteristic
system times. The latter is the case, in nature, for all relevant dynamical
time scales for other than nearly degenerate energy levels. We estimate that,
in the absence of non-radiative relaxation and decoherence, turn-on times
slower than 1 ms (still short by natural standards) induce Fano coherences
between energy eigenstates that are separated by less than 0.9 cm$^{-1}$.


title:
Does the Planetary Dynamo Go Cycling On? Re-examining the Evidence for
  Cycles in Magnetic Reversal Rate

abstract:
  The record of reversals of the geomagnetic field has played an integral role
in the development of plate tectonic theory. Statistical analyses of the
reversal record are aimed at detailing patterns and linking those patterns to
core-mantle processes. The geomagnetic polarity timescale is a dynamic record
and new paleomagnetic and geochronologic data provide additional detail. In
this paper, we examine the periodicity revealed in the reversal record back to
375 million years ago (Ma) using Fourier analysis. Four significant peaks were
found in the reversal power spectra within the 16-40-million-year range (Myr).
Plotting the function constructed from the sum of the frequencies of the
proximal peaks yield a transient 26 Myr periodicity, suggesting chaotic motion
with a periodic attractor. The possible 16 Myr periodicity, a previously
recognized result, may be correlated with pulsation of mantle plumes and
perhaps; more tentatively, with core-mantle dynamics originating near the large
low shear velocity layers in the Pacific and Africa. Planetary magnetic fields
shield against charged particles which can give rise to radiation at the
surface and ionize the atmosphere, which is a loss mechanism particularly
relevant to M stars. Understanding the origin and development of planetary
magnetic fields can shed light on the habitable zone.

categories: astro-ph.EP nlin.CD physics.data-an physics.geo-ph


title: Characterization of intersecting families of maximum size in $PSL(2,q)$

abstract:
  We consider the action of the $2$-dimensional projective special linear group
$PSL(2,q)$ on the projective line $PG(1,q)$ over the finite field $\F_q$, where
$q$ is an odd prime power. A subset $S$ of $PSL(2,q)$ is said to be an
intersecting family if for any $g_1,g_2 \in S$, there exists an element $x\in
PG(1,q)$ such that $x^{g_1}= x^{g_2}$. It is known that the maximum size of an
intersecting family in $PSL(2,q)$ is $q(q-1)/2$. We prove that all intersecting
families of maximum size are cosets of point stabilizers for all odd prime
powers $q>3$.


title: Prediction and Optimal Scheduling of Advertisements in Linear Television

abstract:
  Advertising is a crucial component of marketing and an important way for
companies to raise awareness of goods and services in the marketplace.
Advertising campaigns are designed to convey a marketing image or message to an
audience of potential consumers and television commercials can be an effective
way of transmitting these messages to a large audience. In order to meet the
requirements for a typical advertising order, television content providers must
provide advertisers with a predetermined number of "impressions" in the target
demographic. However, because the number of impressions for a given program is
not known a priori and because there are a limited number of time slots
available for commercials, scheduling advertisements efficiently can be a
challenging computational problem. In this case study, we compare a variety of
methods for estimating future viewership patterns in a target demographic from
past data. We also present a method for using those predictions to generate an
optimal advertising schedule that satisfies campaign requirements while
maximizing advertising revenue.


title: Invariant death

abstract:
  In nematodes, environmental or physiological perturbations alter death's
scaling of time. In human cancer, genetic perturbations alter death's curvature
of time. Those changes in scale and curvature follow the constraining contours
of death's invariant geometry. I show that the constraints arise from a
fundamental extension to the theories of randomness, invariance and scale. A
generalized Gompertz law follows. The constraints imposed by the invariant
Gompertz geometry explain the tendency of perturbations to stretch or bend
death's scaling of time. Variability in death rate arises from a combination of
constraining universal laws and particular biological processes.


title:
Low Complexity Power Allocation Schemes in Regenerative Multi-user Relay
  Networks

abstract:
  In relay assisted wireless communications, the multi-source, single relay and
single destination system (an $M$-1-1 system) is of growing importance, due to
the increased demand for higher network throughput and connectivity.
Previously, power allocation in $M$-1-1 systems have assumed availability of
instantaneous channel state information (CSI), which is rather idealistic. In
this paper we consider an $M$-1-1 Decode-and-Forward (DF), Full-Duplex,
orthogonal frequencey division multiple access (OFDMA) based relay system with
statistical-CSI and analyze the achievable rate $R$ of such a system. We show
how $R$ can only be maximized by numerical power allocation schemes which has a
high-complexity of order $\mathcal O(M^3)$. By introducing a rational
approximation in the achievable rate analysis, we develop two low-complexity
power allocation schemes that can obtain a system achievable rate very close to
the maximum $R$. Most importantly, we show that the complexity of our power
allocation schemes is of order $\mathcal O(M\log M)$. We then show how our
power allocation schemes are suitable for a multi-user relay system, where
either the priority is to maximize system throughput, or where lower
computations in power allocation scheme are essential. The work we present in
this paper will be of value to the design and implementation of real-time
multi-user relay systems operating under realistic channel conditions.


title: Flag Hilbert schemes, colored projectors and Khovanov-Rozansky homology

abstract:
  We construct a categorification of the maximal commutative subalgebra of the
type $A$ Hecke algebra. Specifically, we propose a monoidal functor from the
(symmetric) monoidal category of coherent sheaves on the flag Hilbert scheme to
the (non-symmetric) monoidal category of Soergel bimodules. The adjoint of this
functor allows one to match the Hochschild homology of any braid with the Euler
characteristic of a sheaf on the flag Hilbert scheme. The categorified
Jones-Wenzl projectors studied by Abel, Elias and Hogancamp are idempotents in
the category of Soergel bimodules, and they correspond to the renormalized
Koszul complexes of the torus fixed points on the flag Hilbert scheme. As a
consequence, we conjecture that the endomorphism algebras of the categorified
projectors correspond to the dg algebras of functions on affine charts of the
flag Hilbert schemes. We define a family of differentials $d_{N}$ on these dg
algebras and conjecture that their homology matches that of the
$\mathfrak{gl}_N$ projectors, generalizing earlier conjectures of the first and
third authors with Oblomkov and Shende.


title: The mimetic finite difference method for the Landau-Lifshitz equation

abstract:
  The Landau-Lifshitz equation describes the dynamics of the magnetization
inside ferromagnetic materials. This equation is highly nonlinear and has a
non-convex constraint (the magnitude of the magnetization is constant) which
pose interesting challenges in developing numerical methods. We develop and
analyze explicit and implicit mimetic finite difference schemes for this
equation. These schemes work on general polytopal meshes which provide enormous
flexibility to model magnetic devices with various shapes. A projection on the
unit sphere is used to preserve the magnitude of the magnetization. We also
provide a proof that shows the exchange energy is decreasing in certain
conditions. The developed schemes are tested on general meshes that include
distorted and randomized meshes. The numerical experiments include a test
proposed by the National Institute of Standard and Technology and a test
showing formation of domain wall structures in a thin film.


title:
Learning in games with continuous action sets and unknown payoff
  functions

abstract:
  This paper examines the convergence of no-regret learning in games with
continuous action sets. For concreteness, we focus on learning via "dual
averaging", a widely used class of no-regret learning schemes where players
take small steps along their individual payoff gradients and then "mirror" the
output back to their action sets. In terms of feedback, we assume that players
can only estimate their payoff gradients up to a zero-mean error with bounded
variance. To study the convergence of the induced sequence of play, we
introduce the notion of variational stability, and we show that stable
equilibria are locally attracting with high probability whereas globally stable
equilibria are globally attracting with probability 1. We also discuss some
applications to mixed-strategy learning in finite games, and we provide
explicit estimates of the method's convergence speed.


title: Global anomalous transport of ICRH- and NBI-heated fast ions

abstract:
  By taking advantage of the trace approximation, one can gain an enormous
computational advantage when solving for the global turbulent transport of
impurities. In particular, this makes feasible the study of non-Maxwellian
transport coupled in radius and energy, allowing collisions and transport to be
accounted for on similar time scales, as occurs for fast ions. In this work, we
study the fully-nonlinear ITG-driven trace turbulent transport of locally
heated and injected fast ions. Previous results indicated the existence of
MeV-range minorities heated by cyclotron resonance, and an associated density
pinch effect. Here, we build upon this result using the t3core code to solve
for the distribution of these minorities, consistently including the effects of
collisions, gyrokinetic turbulence, and heating. Using the same tool to study
the transport of injected fast ions, we contrast the qualitative features of
their transport with that of the heated minorities. Our results indicate that
heated minorities are more strongly affected by microturbulence than injected
fast ions. The physical interpretation of this difference provides a possible
explanation for the observed synergy when NBI heating is combined with ICRH.
Furthermore, we move beyond the trace approximation to develop a model which
allows one to easily account for the reduction of anomalous transport due to
the presence of fast ions in electrostatic turbulence.


title:
Convergence of a mass-lumped finite element method for the
  Landau-Lifshitz equation

abstract:
  The dynamics of the magnetic distribution in a ferromagnetic material is
governed by the Landau-Lifshitz equation, which is a nonlinear geometric
dispersive equation with a nonconvex constraint that requires the magnetization
to remain of unit length throughout the domain. In this article, we present a
mass-lumped finite element method for the Landau-Lifshitz equation. This method
preserves the nonconvex constraint at each node of the finite element mesh, and
is energy nonincreasing. We show that the numerical solution of our method for
the Landau-Lifshitz equation converges to a weak solution of the
Landau-Lifshitz-Gilbert equation using a simple proof technique that cancels
out the product of weakly convergent sequences. Numerical tests for both
explicit and implicit versions of the method on a unit square with periodic
boundary conditions are provided for structured and unstructured meshes.


title: Pion transition form factor through Dyson-Schwinger equations

abstract:
  In the framework of Dyson-Schwinger equations (DSE), we compute the
$\gamma^*\gamma\to\pi^0$ transition form factor, $G(Q^2)$. For the first time,
in a continuum approach to quantun chromodynamics (QCD), it was possible to
compute $G(Q^2)$ on the whole domain of space-like momenta. Our result agrees
with CELLO, CLEO and Belle collaborations and, with the well-known asymptotic
QCD limit, $2f_\pi$. Our analysis unifies this prediction with that of the
pion's valence-quark parton distribution amplitude (PDA) and elastic
electromagnetic form factor.