title: Linear and nonlinear fractional Voigt models

abstract:
  We consider fractional generalizations of the ordinary differential equation
that governs the creep phenomenon. Precisely, two Caputo fractional Voigt
models are considered: a rheological linear model and a nonlinear one. In the
linear case, an explicit Volterra representation of the solution is found,
involving the generalized Mittag-Leffler function in the kernel. For the
nonlinear fractional Voigt model, an existence result is obtained through a
fixed point theorem. A nonlinear example, illustrating the obtained existence
result, is given.


title: New formulas for the spectral radius via Aluthge transform

abstract:
  In this paper we give several expressions of spectral radius of a bounded
operator on a Hilbert space, in terms of iterates of Aluthge transformation,
numerical radius and the asymptotic behavior of the powers of this operator.
Also we obtain several characterizations of normaloid operators.


title: BiFold visualization of bipartite datasets

abstract:
  The emerging domain of data-enabled science necessitates development of
algorithms and tools for knowledge discovery. Human interaction with data
through well-constructed graphical representation can take special advantage of
our visual ability to identify patterns. We develop a data visualization
framework, called BiFold, for exploratory analysis of bipartite datasets that
describe binary relationships between groups of objects. Typical data examples
would include voting records, organizational memberships, and pairwise
associations, or other binary datasets. BiFold provides a low dimensional
embedding of data that represents similarity by visual nearness, analogous to
Multidimensional Scaling (MDS). The unique and new feature of BiFold is its
ability to simultaneously capture both within-group and between-group
relationships among objects, enhancing knowledge discovery. We benchmark BiFold
using the {\it Southern Women Dataset}, where social groups are now visually
evident. We construct BiFold plots for two US voting datasets: For the
presidential election outcomes since 1976, BiFold illustrates the evolving
geopolitical structures that underlie these election results. For Senate
congressional voting, BiFold identifies a partisan coordinate, separating
senators into two parties while simultaneously visualizing a
bipartisan-coalition coordinate which captures the ultimate fate of the bills
(pass/fail). Finally, we consider a global cuisine dataset of the association
between recipes and food ingredients. BiFold allows us to visually compare and
contrast cuisines while also allowing identification of signature ingredients
of individual cuisines.


title:
DoReFa-Net: Training Low Bitwidth Convolutional Neural Networks with Low
  Bitwidth Gradients

abstract:
  We propose DoReFa-Net, a method to train convolutional neural networks that
have low bitwidth weights and activations using low bitwidth parameter
gradients. In particular, during backward pass, parameter gradients are
stochastically quantized to low bitwidth numbers before being propagated to
convolutional layers. As convolutions during forward/backward passes can now
operate on low bitwidth weights and activations/gradients respectively,
DoReFa-Net can use bit convolution kernels to accelerate both training and
inference. Moreover, as bit convolutions can be efficiently implemented on CPU,
FPGA, ASIC and GPU, DoReFa-Net opens the way to accelerate training of low
bitwidth neural network on these hardware. Our experiments on SVHN and ImageNet
datasets prove that DoReFa-Net can achieve comparable prediction accuracy as
32-bit counterparts. For example, a DoReFa-Net derived from AlexNet that has
1-bit weights, 2-bit activations, can be trained from scratch using 6-bit
gradients to get 46.1\% top-1 accuracy on ImageNet validation set. The
DoReFa-Net AlexNet model is released publicly.


title: Jordan product commuting maps with $\lambda$-Aluthge transform

abstract:
  Let H and K be two complex Hilbert spaces and B(H) be the algebra of bounded
linear operators from H into itself. The main purpose in this paper is to
obtain a characterization of bijective maps $\Phi$ : B(H) $\rightarrow$ B(K)
satisfying the following condition $\Delta$ $\lambda$ ($\Phi$(A) $\bullet$
$\Phi$(B)) = $\Phi$($\Delta$ $\lambda$ (A $\bullet$ B)) for all A, B $\in$
B(H), where $\Delta$ $\lambda$ (T) stands the $\lambda$-Aluthge transform of
the operator T $\in$ B(H) and A $\bullet$ B = 1 2 (AB + BA) is the Jordan
product of A and B. We prove that a bijective map $\Phi$ satisfies the above
condition, if and only if there exists an unitary operator U : H $\rightarrow$
K, such that $\Phi$ has the form $\Phi$(A) = UAU * for all A $\in$ B(H).


title: MetaZipf. (Re)producing knowledge about city size distributions

abstract:
  Zipf's law for cities is probably the most famous regularity in social
sciences. So much that, a hundred years of publication later, its status is not
clear: is it a law of social organisation? Is it an instrument of description
of city size distributions? Is it an element of validation of geographical
objects (cities and systems of cities in particular)? Empirical estimations of
the rank-size parameters are very numerous and contradict each other. In this
study, we present the results of a reproducible meta-analysis of the largest
pool of papers regarding this issue, obtained from the collection of data made
open and the construction of an online interactive application which allows the
reader to explore this literature. We find that a large part of the variations
observed in the measure of Zipf's coefficient is unnecessary as it comes from
the choice of different technical specifications in the way cities are defined,
whereas some of the current theories to explain the remaining share of
variations are challenged by our results.


title:
Decoherence and disentanglement of qubits detecting scalar fields in an
  expanded universe

abstract:
  We consider Unruh-Wald qubit detector model adopted for the far future region
of an exactly solvable 1+1 dimensional scalar field theory in a
Robertson-Walker expanding spacetime. It is shown that the expansion of the
universe in its history enhances the decoherence of the qubit coupled with a
scalar field. Moreover, we consider two entangled qubits, each locally coupled
a scalar field. The expansion of the universe in its history degrades the
entanglement between the qubits, and can lead to entanglement sudden death if
the initial entanglement is small enough. The details depend on the parameters
characterizing the expansion of the universe. This work, albeit on a toy model,
suggests that the history of the universe might be probed through the coherent
and entanglement behavior of future detectors of quantum fields.


title: Pragmatic factors in image description: the case of negations

abstract:
  We provide a qualitative analysis of the descriptions containing negations
(no, not, n't, nobody, etc) in the Flickr30K corpus, and a categorization of
negation uses. Based on this analysis, we provide a set of requirements that an
image description system should have in order to generate negation sentences.
As a pilot experiment, we used our categorization to manually annotate
sentences containing negations in the Flickr30K corpus, with an agreement score
of K=0.67. With this paper, we hope to open up a broader discussion of
subjective language in image descriptions.


title: Product commuting maps with the $\lambda$-Aluthge transform

abstract:
  Let H and K be two Hilbert spaces and B(H) be the algebra of all bounded
linear operators from H into itself. The main purpose of this paper is to
obtain a characterization of bijective maps $\Phi$ : B(H) $\rightarrow$ B(K)
satisfying the following condition $\Delta$ $\lambda$ ($\Phi$(A)$\Phi$(B)) =
$\Phi$($\Delta$ $\lambda$ (AB)) f orall A, B $\in$ B(H), where $\Delta$
$\lambda$ (T) stands the $\lambda$-Aluthge transform of the operator T $\in$
B(H). More precisely, we prove that a bijective map $\Phi$ satisfies the above
condition, if and only , if $\Phi$(A) = U AU * for all A $\in$ B(H), for some
unitary operator U : H $\rightarrow$ K.


title:
Scalar correlator, Higgs decay into quarks, and scheme variations of the
  QCD coupling

abstract:
  In this work, the perturbative QCD series of the scalar correlation function
$\Psi(s)$ is investigated. Besides ${\rm Im}\Psi(s)$, which is relevant for
Higgs decay into quarks, two other physical correlators, $\Psi^{"}(s)$ and
$D^L(s)$, have been employed in QCD applications like quark mass determinations
or hadronic $\tau$ decays. $D^L(s)$ suffers from large higher-order corrections
and, by resorting to the large-$\beta_0$ approximation, it is shown that this
is related to a spurious renormalon ambiguity at $u=1$. Hence, this correlator
should be avoided in phenomenological analyses. Moreover, it turns out
advantageous to express the quark mass factor, introduced to make the scalar
current renormalisation group invariant, in terms of the renormalisation
invariant quark mass $\hat m_q$. To further study the behaviour of the
perturbative expansion, we introduce a QCD coupling $\hat\alpha_s$, whose
running is explicitly renormalisation scheme independent. The scheme dependence
of $\hat\alpha_s$ is parametrised by a single parameter $C$, being related to
transformations of the QCD scale parameter $\Lambda$. It is demonstrated that
appropriate choices of $C$ lead to a substantial improvement in the behaviour
of the perturbative series for $\Psi^{"}(s)$ and ${\rm Im}\Psi(s)$.


title:
Simulating nonlinear cosmological structure formation with massive
  neutrinos

abstract:
  We present a new method for simulating cosmologies that contain massive
particles with thermal free streaming motion, such as massive neutrinos or
warm/hot dark matter. This method combines particle and fluid descriptions of
the thermal species to eliminate the shot noise known to plague conventional
N-body simulations. We describe this method in detail, along with results for a
number of test cases to validate our method, and check its range of
applicability. Using this method, we demonstrate that massive neutrinos can
produce a significant scale-dependence in the large-scale biasing of deep voids
in the matter field. We show that this scale-dependence may be quantitatively
understood using an extremely simple spherical expansion model which reproduces
the behavior of the void bias for different neutrino parameters.


title: Cobordism categories and moduli spaces of odd dimensional manifolds

abstract:
  We prove that the stable moduli space of $(n-1)$-connected,
$n$-parallelizable, $(2n+1)$-dimensional manifolds is homology equivalent to an
infinite loopspace for $n \geq 4, n \neq 7$. The main novel ingredient is a
version of the cobordism category incorporating surgery data in the form of
Lagrangian subspaces.


title: Variable time flow as an alternative to dark energy

abstract:
  Time is a parameter playing a central role in our most fundamental modelling
of natural laws. Relativity theory shows that the comparison of times measured
by different clocks depends on their relative motions and on the strength of
the gravitational field in which they are embedded. In standard cosmology, the
time parameter is the one measured by fundamental clocks, i.e. clocks at rest
with respect to the expanding space. This proper time is assumed to flow at a
constant rate throughout the whole history of the Universe. We make the
alternative hypothesis that the rate at which cosmological time flows depends
on the global geometric curvature the Universe. Using a simple one-parameter
model for the relation between proper time and curvature, we build a
cosmological model that fits the Type Ia Supernovae data (the best cosmological
standard candles) without the need for dark energy nor probably exotic dark
matter.


title: Entanglement of superconducting qubits via acceleration radiation

abstract:
  We show that simulated relativistic motion can generate entanglement between
artificial atoms and protect them from spontaneous emission. We consider a pair
of superconducting qubits coupled to a resonator mode, where the modulation of
the coupling strength can mimic the harmonic motion of the qubits at
relativistic speeds, generating acceleration radiation. We find the optimal
feasible conditions for generating a stationary entangled state between the
qubits when they are initially prepared in their ground state. Furthermore, we
analyze the effects of motion on the probability of spontaneous emission in the
standard scenarios of single-atom and two-atom superradiance, where one or two
excitations are initially present. Finally, we show that relativistic motion
induces sub-radiance and can generate a Zeno-like effect, preserving the
excitations from radiative decay.


title: Optical properties of superconducting EuFe2(As1-xPx)2

abstract:
  We present a broadband optical-conductivity study of superconducting
single-crystalline EuFe2(As1-xPx)2 with three different substitutional levels.
We analyze the normal-state electrodynamics by decomposing the conductivity
spectra using a Drude-Lorentz model with two Drude terms representing two
groups of carriers with different scattering rates. The analysis reveals that
the scattering rate of at least one of the Drude components develops linearly
with temperature for each doping level. This points towards strong
electron-electron correlations and a non-Fermi-liquid behavior in the
P-substituted superconducting Eu-122 pnictides. We also detect a transfer of
the spectral weight from mid-infrared to higher frequencies and assign it to
the Hund's-rule coupling between itinerant and localized carriers. The
conductivity spectra below the superconducting transition show no sharp
features to be associated with the dirty-limit superconducting BCS gaps. We
interpret these results in terms of clean-limit superconductivity in
EuFe2(As1-xPx)2. The best parametrization fit can be achieved using a two-gap
model. We find that the larger gap at the hole pockets of the Fermi surface is
likely to be isotropic, while the smaller gap at the electron pockets is
anisotropic or even nodal.


title: A constant-time algorithm for middle levels Gray codes

abstract:
  For any integer $n\geq 1$ a middle levels Gray code is a cyclic listing of
all $n$-element and $(n+1)$-element subsets of $\{1,2,\ldots,2n+1\}$ such that
any two consecutive subsets differ in adding or removing a single element. The
question whether such a Gray code exists for any $n\geq 1$ has been the subject
of intensive research during the last 30 years, and has been answered
affirmatively only recently [T. M\"utze. Proof of the middle levels conjecture.
Proc. London Math. Soc., 112(4):677--713, 2016]. In a follow-up paper [T.
M\"utze and J. Nummenpalo. An efficient algorithm for computing a middle levels
Gray code. To appear in ACM Transactions on Algorithms, 2018] this existence
proof was turned into an algorithm that computes each new set in the Gray code
in time $\mathcal{O}(n)$ on average. In this work we present an algorithm for
computing a middle levels Gray code in optimal time and space: each new set is
generated in time $\mathcal{O}(1)$ on average, and the required space is
$\mathcal{O}(n)$.


title: On pair correlation for generic diagonal forms

abstract:
  We establish new pair correlation results for certain generic homogenous
diagonal forms evaluated on the integers. Methods are analytic leading to
explicit quantitative statements.


title: Taming the higher power corrections in semileptonic B decays

abstract:
  We study the effect of dimension 7 and 8 operators on inclusive semileptonic
B decays and the extraction of |Vcb|. Using moments of semileptonic B decay
spectra and information based on the Lowest-Lying State saturation
Approximation (LLSA) we perform a global fit of the nonperturbative parameters
of the heavy quark expansion including for the first time the O(1/mb^{4,5})
contributions. Higher power corrections appear to have a very small effect on
the extraction of |Vcb|, independently of the weight we attribute to the LLSA.


title: Scheme variations of the QCD coupling and hadronic $\tau$ decays

abstract:
  The Quantum Chromodynamics (QCD) coupling, $\alpha_s$, is not a physical
observable of the theory since it depends on conventions related to the
renormalization procedure. We introduce a definition of the QCD coupling,
denoted by $\hat\alpha_s$, whose running is explicitly renormalization scheme
invariant. The scheme dependence of the new coupling $\hat\alpha_s$ is
parameterized by a single parameter $C$, related to transformations of the QCD
scale $\Lambda$. It is demonstrated that appropriate choices of $C$ can lead to
substantial improvements in the perturbative prediction of physical
observables. As phenomenological applications, we study $e^+e^-$ scattering and
decays of the $\tau$ lepton into hadrons, both being governed by the QCD Adler
function.


title: Vortex reconnection in the three dimensional Navier-Stokes equations

abstract:
  We prove that the vortex structures of solutions to the 3D Navier-Stokes
equations can change their topology without any loss of regularity. More
precisely, we construct smooth high-frequency solutions to the Navier-Stokes
equations where vortex lines and vortex tubes of arbitrarily complicated
topologies are created and destroyed in arbitrarily small times. This instance
of vortex reconnection is structurally stable and in perfect agreement with the
existing computer simulations and experiments. We also provide a
(non-structurally stable) scenario where the destruction of vortex structures
is instantaneous.


title: Understanding Innovation to Drive Sustainable Development

abstract:
  Innovation is among the key factors driving a country's economic and social
growth. But what are the factors that make a country innovative? How do they
differ across different parts of the world and different stages of development?
In this work done in collaboration with the World Economic Forum (WEF), we
analyze the scores obtained through executive opinion surveys that constitute
the WEF's Global Competitiveness Index in conjunction with other country-level
metrics and indicators to identify actionable levers of innovation. The
findings can help country leaders and organizations shape the policies to drive
developmental activities and increase the capacity of innovation.


title:
Resolving the Schwarzschild singularity in both classic and quantum
  gravity

abstract:
  The Schwarzschild singularity's resolution has key values in cracking the key
mysteries related with black holes, the origin of their horizon entropy and the
information missing puzzle involved in their evaporations. We provide in this
work the general dynamic inner metric of collapsing stars with horizons and
with non-trivial radial mass distributions. We find that static central
singularities are not the final state of the system. Instead, the final state
of the system is a periodically zero-cross breathing ball. Through 3+1
decomposed general relativity and its quantum formulation, we establish a
functional Schr\"odinger equation controlling the micro-state of this breathing
ball and show that, the system configuration with all the matter concentrating
on the central point is not the unique eigen-energy-density solution. Using a
Bohr-Sommerfield like "orbital" quantisation assumption, we show that for each
black hole of horizon radius $r_h$, there are about
$e^{r_h^2/\ell^2_\mathrm{pl}}$ allowable eigen-energy-density profile. This
naturally leads to physic interpretations for the micro-origin of horizon
entropy, as well as solutions to the information missing puzzle involved in
Hawking radiations.


title: On the prediction loss of the lasso in the partially labeled setting

abstract:
  In this paper we revisit the risk bounds of the lasso estimator in the
context of transductive and semi-supervised learning. In other terms, the
setting under consideration is that of regression with random design under
partial labeling. The main goal is to obtain user-friendly bounds on the
off-sample prediction risk. To this end, the simple setting of bounded response
variable and bounded (high-dimensional) covariates is considered. We propose
some new adaptations of the lasso to these settings and establish oracle
inequalities both in expectation and in deviation. These results provide
non-asymptotic upper bounds on the risk that highlight the interplay between
the bias due to the mis-specification of the linear model, the bias due to the
approximate sparsity and the variance. They also demonstrate that the presence
of a large number of unlabeled features may have significant positive impact in
the situations where the restricted eigenvalue of the design matrix vanishes or
is very small.


title:
Semi-classical resonances associated with a periodic orbit of hyperbolic
  type

abstract:
  We consider in this Note resonances for a $h$-Pseudo-Differential Operator
$H(x,hD_x;h)$ on $L^2(M)$ induced by a periodic orbit of hyperbolic type, as
arises for Schr\"odinger operator with AC Stark effect when $M={\bf R}^n$, or
the geodesic flow on an axially symmetric manifold $M$, extending Poincar\'e
example of Lagrangian systems with 2 degrees of freedom. We generalize the
framework of [G\'eSj], in the sense that we allow for hyperbolic and elliptic
eigenvalues of Poincar\'e map, and look for so-called semi-excited resonances
with imaginary part of magnitude $-h\log h$, or $h^s$, with $0<s<1$.


title: Chirality modifies the interaction between knots

abstract:
  In this study we consider an idealization of a typical optical tweezers
experiment involving a semiflexible double-knotted polymer, with steric
hindrance and persistence length matching those of dsDNA in high salt
concentration, under strong stretching. Using exhaustive Molecular Dynamics
simulations we show that not only does a double-knotted dsDNA filament under
tension possess a free energy minimum when the two knots are intertwined, but
also that the depth of this minimum depends on the relative chirality of the
two knots. We rationalize this dependence of the effective interaction on the
chirality in terms of a competition between chain entropy and bending energy.


title:
The Panchromatic Hubble Andromeda Treasury XV. The BEAST: Bayesian
  Extinction and Stellar Tool

abstract:
  We present the Bayesian Extinction And Stellar Tool (BEAST), a probabilistic
approach to modeling the dust extinguished photometric spectral energy
distribution of an individual star while accounting for observational
uncertainties common to large resolved star surveys. Given a set of photometric
measurements and an observational uncertainty model, the BEAST infers the
physical properties of the stellar source using stellar evolution and
atmosphere models and constrains the line of sight extinction using a newly
developed mixture model that encompasses the full range of dust extinction
curves seen in the Local Group. The BEAST is specifically formulated for use
with large multi-band surveys of resolved stellar populations. Our approach
accounts for measurement uncertainties and any covariance between them due to
stellar crowding (both systematic biases and uncertainties in the bias) and
absolute flux calibration, thereby incorporating the full information content
of the measurement. We illustrate the accuracy and precision possible with the
BEAST using data from the Panchromatic Hubble Andromeda Treasury. While the
BEAST has been developed for this survey, it can be easily applied to similar
existing and planned resolved star surveys.


title: Asymptotically Optimal Approximation Algorithms for Coflow Scheduling

abstract:
  Many modern datacenter applications involve large-scale computations composed
of multiple data flows that need to be completed over a shared set of
distributed resources. Such a computation completes when all of its flows
complete. A useful abstraction for modeling such scenarios is a {\em coflow},
which is a collection of flows (e.g., tasks, packets, data transmissions) that
all share the same performance goal.
  In this paper, we present the first approximation algorithms for scheduling
coflows over general network topologies with the objective of minimizing total
weighted completion time. We consider two different models for coflows based on
the nature of individual flows: circuits, and packets. We design
constant-factor polynomial-time approximation algorithms for scheduling
packet-based coflows with or without given flow paths, and circuit-based
coflows with given flow paths. Furthermore, we give an $O(\log n/\log \log
n)$-approximation polynomial time algorithm for scheduling circuit-based
coflows where flow paths are not given (here $n$ is the number of network
edges).
  We obtain our results by developing a general framework for coflow schedules,
based on interval-indexed linear programs, which may extend to other coflow
models and objective functions and may also yield improved approximation bounds
for specific network scenarios. We also present an experimental evaluation of
our approach for circuit-based coflows that show a performance improvement of
at least 22% on average over competing heuristics.


title:
Geometric approach to entanglement quantification with polynomial
  measures

abstract:
  We show that the quantification of entanglement of any rank-2 state with any
polynomial entanglement measure can be recast as a geometric problem on the
corresponding Bloch sphere. This approach provides novel insight into the
properties of entanglement and allows us to relate different polynomial
measures to each other, simplifying their quantification. In particular,
unveiling and exploiting the geometric structure of the concurrence for two
qubits, we show that the convex roof of any polynomial measure of entanglement
can be quantified exactly for all rank-2 states of an arbitrary number of
qubits which have only one or two unentangled states in their range. We give
explicit examples by quantifying the three-tangle exactly for several
representative classes of three-qubit states. We further show how our methods
can be used to obtain analytical results for entanglement of more complex
states if one can exploit symmetries in their geometric representation.


title: An high definition view of the COSMOS Wall at z~0.73

abstract:
  We present a study of a large filamentary structure at z~0.73 in the field of
the COSMOS survey, the so-called COSMOS Wall. This structure encompasses a
comprehensive range of environments from a dense cluster and a number of galaxy
groups to filaments, less dense regions, and adjacent voids. It thus provides a
valuable laboratory for the accurate mapping of environmental effects on galaxy
evolution at a look-back time of ~6.5 Gyr, when the Universe was roughly half
its present age.
  We performed deep spectroscopic observations with VIMOS at VLT of a K-band
selected sample of galaxies in this complex structure, building a sample of
galaxies complete in galaxy stellar mass down to a lower limit of log(M/M_sun)~
9.8, which is significantly deeper than previously available data. Thanks to
its location within the COSMOS survey, each galaxy benefits from a wealth of
ancillary information.
  In this paper we detail the survey strategy and weighting scheme adopted to
account for the biases introduced by the photometric pre-selection of our
targets. We present our galaxy stellar mass and rest-frame magnitudes estimates
together with a group catalog obtained with our new data and their member
galaxies color/mass distribution.
  Owing to to our new sample we can perform a detailed, high definition mapping
of the complex COSMOS Wall structure. The sharp environmental information,
coupled with high quality spectroscopic information and rich ancillary data
available in the COSMOS field, enables a detailed study of galaxy properties as
a function of local environment in a redshift slice where environmental effects
are important, and in a stellar mass range where mass and environment driven
effects are both at work.


title: Fundamental Implications of Intergalactic Magnetic Field Observations

abstract:
  Helical intergalactic magnetic fields at the $\sim 10^{-14}~{\rm G}$ level on
$\sim 10~{\rm Mpc}$ length scales are indicated by current gamma ray
observations. The existence of magnetic fields in cosmic voids and their
non-trivial helicity suggest that they must have originated in the early
universe and thus have implications for the fundamental interactions. I combine
present knowledge of the observational constraints and the dynamics of
cosmological magnetic fields to derive characteristics that would need to be
explained by the magnetic field generation mechanism. The importance of CP
violation and a possible crucial role for chiral effects in the early universe
are pointed out.


title:
Extended homologous series of Sn-O layered systems: a first-principles
  study

abstract:
  Apart from the most studied tin-oxide compounds, SnO and SnO2, intermediate
states have been claimed to exist for more than a hundred years. In addition to
the known homologous series (Seko et al., Phys. Rev. Lett. 100, 045702 (2008)),
we here predict the existence of several new compounds with an O concentration
between 50 % (SnO) and 67 % (SnO2). All these intermediate compounds are
constructed from removing one or more (101) oxygen layers of SnO2. Since the
van der Waals (vdW) interaction is known to be important for the Sn-Sn
interlayer distances, we use a vdW-corrected functional, and compare these
results with results obtained with PBE and hybrid functionals. We present the
electronic properties of the intermediate structures and we observe a decrease
of the band gap when (i) the O concentration increases and (ii) more SnO-like
units are present for a given concentration. The contribution of the different
atoms to the valence and conduction band is also investigated.


title:
Analysis of uncertainties in alpha-particle optical-potential assessment
  below the Coulomb barrier

abstract:
  Background: Recent high-precision measurements of alpha-induced reaction data
below the Coulomb barrier have pointed out questions of the alpha-particle
optical-model potential (OMP) which are yet open within various mass ranges.
Purpose: The applicability of a previous optical potential and eventual
uncertainties and/or systematic errors of the OMP assessment at low energies
can be further considered on this basis. Method: Nuclear model parameters based
on the analysis of recent independent data, particularly gamma-ray strength
functions, have been involved within statistical model calculation of the
(alpha,x) reaction cross sections. Results: The above-mentioned potential
provides a consistent description of the recent alpha-induced reaction data
with no empirical rescaling factors of the and/or nucleon widths. Conclusions:
A suitable assessment of alpha-particle optical potential below the Coulomb
barrier should involve the statistical-model parameters beyond this potential
on the basis of a former analysis of independent data.


title:
Role of vertex corrections in the matrix formulation of the random phase
  approximation for the multiorbital Hubbard model

abstract:
  In the framework of a multiorbital Hubbard model description of
superconductivity, a matrix formulation of the superconducting pairing
interaction that has been widely used is designed to treat spin, charge and
orbital fluctuations within a random phase approximation (RPA). In terms of
Feynman diagrams, this takes into account particle-hole ladder and bubble
contributions as expected. It turns out, however, that this matrix formulation
also generates additional terms which have the diagrammatic structure of vertex
corrections. Here we examine these terms and discuss the relationship between
the matrix-RPA superconducting pairing interaction and the Feynman diagrams
that it sums.


title:
Essential self-adjointness of powers of first-order differential
  operators on non-compact manifolds with low-regularity metrics

abstract:
  We consider first-order differential operators with locally bounded
measurable coefficients on vector bundles with measurable coefficient metrics.
Under a mild set of assumptions, we demonstrate the equivalence between the
essential self-adjointness of such operators to a negligible boundary property.
When the operator possesses higher regularity coefficients, we show that higher
powers are essentially self-adjoint if and only if this condition is satisfied.
In the case that the low-regularity Riemannian metric induces a complete length
space, we demonstrate essential self-adjointness of the operator and its higher
powers up to the regularity of its coefficients. We also present applications
to Dirac operators on Dirac bundles when the metric is non-smooth.


title:
Revisiting on-shell renormalization conditions in theories with flavour
  mixing

abstract:
  In this review, we present a derivation of the on-shell renormalization
conditions for scalar and fermionic fields in theories with and without parity
conservation. We also discuss the specifics of Majorana fermions. Our approach
only assumes a canonical form for the renormalized propagators and exploits the
fact that the inverse propagators are non-singular in $\varepsilon = p^2 -
m_n^2$, where $p$ is the external four-momentum and $m_n$ is a pole mass. In
this way, we obtain full agreement with commonly used on-shell conditions. We
also discuss how they are implemented in renormalization.


title:
A Novel Quasi-One-Dimensional Topological Insulator in Bismuth Iodide
  $\beta$-Bi$_4$I$_4$

abstract:
  Recent progress in the field of topological states of matter(1,2) has largely
been initiated by the discovery of bismuth and antimony chalcogenide bulk
topological insulators (TIs)(3-6), followed by closely related ternary
compounds(7-16) and predictions of several weak TIs(17-19). However, both the
conceptual richness of Z$_2$ classification of TIs as well as their structural
and compositional diversity are far from being fully exploited. Here, a new
Z$_2$ topological insulator is theoretically predicted and experimentally
confirmed in the $\beta$-phase of quasi-one-dimensional bismuth iodide
Bi$_4$I$_4$. The electronic structure of $\beta$-Bi$_4$I$_4$, characterized by
Z$_2$ invariants (1;110), is in proximity of both the weak TI phase (0;001) and
the trivial insulator phase (0;000). Our angle-resolved photoemission
spectroscopy measurements on the (001) surface reveal a highly anisotropic
band-crossing feature located at the point of the surface Brillouin zone and
showing no dispersion with the photon energy, thus being fully consistent with
the theoretical prediction.


title: Single quark entropy and the Polyakov loop

abstract:
  We study Quantum Chromodynamics (QCD) with 2+1 flavors with almost physical
quark masses using the highly improved staggered quark action (HISQ). We
calculate the Polyakov loop in a wide temperature range, obtain the free energy
and the entropy of a single static quark and discuss the QCD crossover region
in detail. We show that the entropy has a peak close to the chiral crossover
and consider the consequences for the deconfinement aspects of the crossover
phenomena. We study the renormalized Polyakov loop susceptibilities and place
them into the context of the crossover. We also obtain a quantitative result
for the onset of weak coupling behavior at high temperatures.


title: Gauge-invariant description of Higgs phenomenon and quark confinement

abstract:
  We propose a novel description for the Higgs mechanism by which a gauge boson
acquires the mass. We do not assume spontaneous breakdown of gauge symmetry
signaled by a non-vanishing vacuum expectation value of the scalar field. In
fact, we give a manifestly gauge-invariant description of the Higgs mechanism
in the operator level, which does not rely on spontaneous symmetry breaking.
This enables us to discuss the confinement-Higgs complementarity from a new
perspective. The "Abelian" dominance in quark confinement of the Yang-Mills
theory is understood as a consequence of the gauge-invariant Higgs phenomenon
for the relevant Yang-Mills-Higgs model.


title:
Dirac fermions at high-index surfaces of bismuth chalcogenide
  topological insulator nanostructures

abstract:
  Binary bismuth chalcogenides Bi$_2$Se$_3$, Bi$_2$Te$_3$, and related
materials are currently being extensively investigated as the reference
topological insulators (TIs) due to their simple surface-state band dispersion
(single Dirac cone) and relatively large bulk band gaps. Nanostructures of TIs
are of particular interest as an increased surface-to-volume ratio enhances the
contribution of surfaces states, meaning they are promising candidates for
potential device applications. So far, the vast majority of research efforts
have focused on the low-energy (0001) surfaces, which correspond to natural
cleavage planes in these layered materials. However, the surfaces of
low-dimensional nanostructures (nanoplatelets, nanowires, nanoribbons)
inevitably involve higher-index facets. We perform a systematic ab initio
investigation of the surfaces of bismuth chalcogenide TI nanostructures
characterized by different crystallographic orientations, atomic structures and
stoichiometric compositions. We find several stable terminations of high-index
surfaces, which can be realized at different values of the chemical potential
of one of constituent elements. For the uniquely defined stoichiometric
termination, the topological Dirac fermion states are shown to be strongly
anisotropic with a clear dependence of Fermi velocities and spin polarization
on the surface orientation. Self-doping effects and the presence of
topologically trivial mid-gap states are found to characterize the
non-stoichiometric surfaces. The results of our study pave the way towards
experimental control of topologically protected surface states in bismuth
chalcogenide nanostructures.


title:
Gender Representation on Journal Editorial Boards in the Mathematical
  Sciences

abstract:
  We study gender representation on the editorial boards of 435 journals in the
mathematical sciences. Women are known to comprise approximately 15% of
tenure-stream faculty positions in doctoral-granting mathematical sciences
departments in the United States. Compared to this pool, the likely source of
journal editorships, we find that 8.9% of the 13067 editorships in our study
are held by women. We describe group variations within the editorships by
identifying specific journals, subfields, publishers, and countries that
significantly exceed or fall short of this average. To enable our study, we
develop a semi-automated method for inferring gender that has an estimated
accuracy of 97.5%. Our findings provide the first measure of gender
distribution on editorial boards in the mathematical sciences, offer insights
that suggest future studies in the mathematical sciences, and introduce new
methods that enable large-scale studies of gender distribution in other fields.


title: Polymetric Rhythmic Feel for a Cognitive Drum Computer

abstract:
  This paper addresses a question about music cognition: how do we derive
polymetric structures. A preference rule system is presented which is
implemented into a drum computer. The preference rule system allows inferring
local polymetric structures, like two-over-three and three-over-two. By
analyzing the micro-timing of West African percussion music a timing pattern
consisting of six pulses was discovered. It integrates binary and ternary
rhythmic feels. The presented drum computer integrates the discovered
superimposed polymetric swing (timing and velocity) appropriate to the rhythmic
sequence the user inputs. For binary sequences, the amount of binary swing is
increased and for ternary sequences, the ternary swing is increased.


title: Evidence for collectivity in pp collisions at the LHC

abstract:
  Measurements of two- and multi-particle angular correlations in pp collisions
at sqrt(s) = 5, 7, and 13 TeV are presented as a function of charged-particle
multiplicity. The data, corresponding to integrated luminosities of 1.0 inverse
picobarn (5 TeV), 6.2 inverse picobarns (7 TeV), and 0.7 inverse picobarns (13
TeV), were collected using the CMS detector at the LHC. The second-order (v[2])
and third-order (v[3]) azimuthal anisotropy harmonics of unidentified charged
particles, as well as v[2] of K0 short and Lambda/anti-Lambda particles, are
extracted from long-range two-particle correlations as functions of particle
multiplicity and transverse momentum. For high-multiplicity pp events, a mass
ordering is observed for the v[2] values of charged hadrons (mostly pions), K0
short, and Lambda/anti-Lambda, with lighter particle species exhibiting a
stronger azimuthal anisotropy signal below pt of about 2 GeV/c. For 13 TeV
data, the v[2] signals are also extracted from four- and six-particle
correlations for the first time in pp collisions, with comparable magnitude to
those from two-particle correlations. These observations are similar to those
seen in pPb and PbPb collisions, and support the interpretation of a collective
origin for the observed long-range correlations in high-multiplicity pp
collisions.


title:
A variational H(div) finite element discretisation approach for perfect
  incompressible fluids

abstract:
  We propose a finite element discretisation approach for the incompressible
Euler equations which mimics their geometric structure and their variational
derivation. In particular, we derive a finite element method that arises from a
nonholonomic variational principle and an appropriately defined Lagrangian,
where finite element H(div) vector fields are identified with advection
operators; this is the first successful extension of the structure-preserving
discretisation of Pavlov et al. (2009) to the finite element setting. The
resulting algorithm coincides with the energy-conserving scheme presented in
Guzm\'an et al. (2016). Through the variational derivation, we discover that it
also satisfies a discrete analogous of Kelvin's circulation theorem. Further,
we propose an upwind-stabilised version of the scheme which dissipates
enstrophy whilst preserving energy conservation and the discrete Kelvin's
theorem. We prove error estimates for this version of the scheme, and we study
its behaviour through numerical tests.


title:
Electron Two-stream Instability and Its Application in Solar and
  Heliophysics

abstract:
  It is well known that electron beams accelerated in solar flares can drive
two-stream instability and produce radio bursts in the solar corona as well as
in the interplanetary medium. Recent observations show that the solar wind
likely originates from nanoflare-like events near the surface of the Sun where
locally heated plasma escapes along open field lines into space. Recent
numerical simulations and theoretical studies show that electron two-stream
instability (ETSI) driven by nanoflare-accelerated electron beams can produce
the observed nanoflare-type radio bursts, the non-Maxwellian electron velocity
distribution function of the solar wind, and the kinetic scale turbulence in
solar wind. This brief review focus on the basic theoretical framework and
recent progress in the nonlinear evolution of ETSI, including the formation of
electron holes, Langmuir wave generation in warm plasma, and the nonlinear
modulation instability and Langmuir collapse. Potential applications in
heliophysics and astrophysics are discussed.


title: Primal-dual interior-point multigrid method for topology optimization

abstract:
  An interior point method for the structural topology optimization is
proposed. The linear systems arising in the method are solved by the conjugate
gradient method preconditioned by geometric multigrid. The resulting method is
then compared with the so-called optimality condition method, an established
technique in topology optimization. This method is also equipped with the
multigrid preconditioned conjugate gradient algorithm. We conclude that, for
large scale problems, the interior point method with an inexact iterative
linear solver is superior to any other variant studied in the paper.


title: Regular global attractors for wave equations with degenerate memory

abstract:
  We consider the wave equation with degenerate viscoelastic dissipation
recently examined in Cavalcanti, Fatori, and Ma, Attractors for wave equations
with degenerate memory, J. Differential Equations (2016). Under some additional
assumptions, we show the existence of a compact absorbing set. This result
provides further regularity for the global attractor and shows that it consists
of regular solutions.


title:
Application of the generalized Kirchhoff's law to calculation of
  photoluminescence spectra of one-dimensional photonic crystals

abstract:
  The approach based on the generalized Kirchhoff's law for calculating
photoluminescence (PL) spectra of one-dimensional (1D) multi-layered
structures, in particular, 1D photonic crystals has been developed. It is valid
in the local thermodynamic equilibrium approximation and leads to simple and
explicit expression for the photoluminescence intensity. In the framework of
the present theory the analytical expression for the spontaneous emission
intensity enhancement factor (IEF) for a 1D photonic crystal has been derived.
It takes a particularly simple form in the case of a sufficiently large number
of the layers and is well suitable for analysis; in particular, it explains the
difference in the emission intensity at frequencies near different edges of
photonic band-gaps (PBGs), where the intensity is relatively high, and
specificity of suppression of the emission in a given frequency range. Also,
the developed approach is discussed in connection with the standard method
using the Fermi's golden rule and the concept of the local density of (optical)
states (LDOS).


title:
Parallel Priority-Flood Depression Filling For Trillion Cell Digital
  Elevation Models On Desktops Or Clusters

abstract:
  Algorithms for extracting hydrologic features and properties from digital
elevation models (DEMs) are challenged by large datasets, which often cannot
fit within a computer's RAM. Depression filling is an important preconditioning
step to many of these algorithms. Here, I present a new, linearly-scaling
algorithm which parallelizes the Priority-Flood depression-filling algorithm by
subdividing a DEM into tiles. Using a single-producer, multi-consumer design,
the new algorithm works equally well on one core, multiple cores, or multiple
machines and can take advantage of large memories or cope with small ones.
Unlike previous algorithms, the new algorithm guarantees a fixed number of
memory access and communication events per subdivision of the DEM. In
comparison testing, this results in the new algorithm running generally faster
while using fewer resources than previous algorithms. For moderately sized
tiles, the algorithm exhibits ~60% strong and weak scaling efficiencies up to
48 cores, and linear time scaling across datasets ranging over three orders of
magnitude. The largest dataset on which I run the algorithm has 2 trillion
(2*10^12) cells. With 48 cores, processing required 4.8 hours wall-time (9.3
compute-days). This test is three orders of magnitude larger than any
previously performed in the literature. Complete, well-commented source code
and correctness tests are available for download from a repository.


title: Exact special twist method for quantum Monte Carlo simulations

abstract:
  We present a systematic investigation of the special twist method introduced
by Rajagopal $\textit{et al.}$ [ Phys. Rev. B 51, 10591 (1995) ] for reducing
finite-size effects in correlated calculations of periodic extended systems
with Coulomb interactions and Fermi statistics. We propose a procedure for
finding special twist values which, at variance with previous applications of
this method, reproduce the energy of the mean-field infinite-size limit
solution within an adjustable (arbitrarily small) numerical error. This choice
of the special twist is shown to be the most accurate single-twist solution for
curing one-body finite-size effects in correlated calculations. For these
reasons we dubbed our procedure "exact special twist" (EST). EST only needs a
fully converged independent-particles or mean-field calculation within the
primitive cell and a simple fit to find the special twist along a specific
direction in the Brillouin zone. We first assess the performances of EST in a
simple correlated model such as the 3D electron gas. Afterwards, we test its
efficiency within $\textit{ab initio}$ quantum Monte Carlo simulations of
metallic elements of increasing complexity. We show that EST displays an
overall good performance in reducing finite-size errors comparable to the
widely used twist average technique but at a much lower computational cost,
since it involves the evaluation of just one wavefunction. We also demonstrate
that the EST method shows similar performances in the calculation of
correlation functions, such as the ionic forces for structural relaxation and
the pair radial distribution function in liquid hydrogen. Our conclusions point
to the usefulness of EST for correlated supercell calculations, our method will
be particularly relevant when the physical problem under consideration requires
large periodic cells.


title: ArbiLoMod: Local Solution Spaces by Random Training in Electrodynamics

abstract:
  The simulation method ArbiLoMod has the goal to provide users of Finite
Element based simulation software with quick re-simulation after localized
changes to the model under consideration. It generates a Reduced Order Model
(ROM) for the full model without ever solving the full model. To this end, a
localized variant of the Reduced Basis method is employed, solving only small
localized problems in the generation of the reduced basis. The key to quick
re-simulation lies in recycling most of the localized basis vectors after a
localized model change. In this publication, ArbiLoMod's local training
algorithm is analyzed numerically for the non-coercive problem of time harmonic
Maxwell's equations in 2D, formulated in H(curl).


title: Non-local meta-conformal invariance in diffusion-limited erosion

abstract:
  The non-stationary relaxation and physical ageing in the diffusion-limited
erosion process ({\sc dle}) is studied through the exact solution of its
Langevin equation, in $d$ spatial dimensions. The dynamical exponent $z=1$, the
growth exponent $\beta=\max(0,(1-d)/2)$ and the ageing exponents $a=b=d-1$ and
$\lambda_C=\lambda_R=d$ are found. In $d=1$ spatial dimension, a new
representation of the meta-conformal Lie algebra, isomorphic to
$\mathfrak{sl}(2,\mathbb{R})\oplus\mathfrak{sl}(2,\mathbb{R})$, acts as a
dynamical symmetry of the noise-averaged {\sc dle} Langevin equation. Its
infinitesimal generators are non-local in space. The exact form of the full
time-space dependence of the two-time response function of {\sc dle} is
reproduced for $d=1$ from this symmetry. The relationship to the
terrace-step-kink model of vicinal surfaces is discussed.

categories: cond-mat.stat-mech hep-th math-ph math.MP


title:
On the Design of Attitude Observers on the Special Orthogonal Group
  $SO(3)$

abstract:
  We revisit the nonlinear complimentary filter on $SO(3)$, previously proposed
in the literature, and provide the (time-explicit) solution to the matrix ODE
governing the attitude estimation error in the absence of measurement errors.
The stability and performance properties of this filter can be easily deduced
from the obtained closed-from solution. Thereafter, we consider two nonlinear
complimentary filters (with state-dependent gains) which are shown to exhibit
improved stability and performance proprieties compared to the traditional
filter. We perform robustness analysis for the three discussed attitude filters
on $SO(3)$ with respect to attitude and angular velocity measurement errors.
Specifically, we show that the state-dependent-gain filters may exhibit
improved robustness to gyro measurement disturbances and a better disturbance
attenuation levels. Simulation results are performed to confirm the obtained
theoretical results.


title:
The Muon Experimental Anomalies Are Explained by a New Interaction
  Proportional to Charge

abstract:
  The "proton size puzzle" and the "muon anomalous moment problem" are
incomplete descriptions of significant discrepancies of Standard Model
calculations with experiments. What is particularly new is that the experiments
and theory confront a new regime of ultra-precise physics where traditional
piece-meal analysis methods fail to be self-consistent. At current levels of
precision the proton size $r_{p}$, the Rydberg constant $R_{\infty}$, the fine
structure constant $\alpha$ and the electron mass (Compton wavelength
$\lambda_{c}$) are inextricably coupled, so that the actual discrepancies might
be almost anywhere, while merely {\it appearing} to be muon-derived through a
historical order of assumptions. We have conducted a new global fit to all of
the relevant data using the entire body of Standard Model theory. A
conventional $\chi^{2}$ statistic is used to fit all relevant fundamental
constants with and without a generic "no-name" boson of undetermined spin that
interacts universally with leptons and hadrons proportional to electric charge.
The analysis discovers a new local minimum region of $\chi^{2}$ where all of
$r_{p}, \, R_{\infty}, \, \alpha, \, \lambda_{e}$ have new values compared to
previous work, while accommodating all of the data, unlike previous
determinations. A new particle $X$, possibly related to the "dark photon" but
more generally defined, is predicted to be observed in electron- and muon-based
experiments.


title: On the zeroth stable $\mathbb{A}^1$-homotopy group of a smooth curve

abstract:
  We provide a cohomological interpretation of the zeroth stable
$\mathbb{A}^1$-homotopy group of a smooth curve over an infinite perfect field.
We show that this group is isomorphic to the first Nisnevich (or Zariski)
cohomology group of a certain sheaf closely related to the first Milnor--Witt
$\mathrm{K}$-theory sheaf. This cohomology group can be computed using an
explicit Gersten-type complex. We show that if the base field is algebraically
closed then the zeroth stable $\mathbb{A}^1$-homotopy group of a smooth curve
coincides with the zeroth Suslin homology group that was identified by Suslin
and Voevodsky with a relative Picard group. As a consequence we reobtain a
version of Suslin's rigidity theorem.


title: In-medium P-wave quarkonium from the complex lattice QCD potential

abstract:
  We extend our lattice QCD potential based study arXiv:1509.07366 (JHEP 1512
(2015) 101) of the in-medium properties of heavy quark bound states to P-wave
bottomonium and charmonium. Similar to the behavior found in the S-wave channel
their spectra show a characteristic broadening, as well as mass shifts to lower
energy with increasing temperature. In contrast to the S-wave states, finite
angular momentum leads to the survival of spectral peaks even at temperatures,
where the continuum threshold reaches below the bound state remnant mass. We
elaborate on the ensuing challenges in defining quarkonium dissolution, present
estimates of melting temperatures for the spin averaged $\chi_b$ and $\chi_c$
states and contrast the findings to recent direct lattice NRQCD studies of
P-wave quarkonium. As an application to heavy-ion collisions we estimate the
contribution of feed down to S-wave quarkonium through the P-wave states after
freezeout.


title: One-Loop Transition Amplitudes in the D1D5 CFT

abstract:
  We consider the issue of thermalization in the D1D5 CFT. Thermalization is
expected to correspond to the formation of a black hole in the dual gravity
theory. We start from the orbifold point, where the theory is essentially free,
and does not thermalize. In earlier work it was noted that there was no clear
thermalization effect when the theory was deformed off the orbifold point to
first order in the relevant twist perturbation. In this paper we consider the
deformation to second order in the twist, where we do find effects that can
cause thermalization of an initial perturbation. We consider a 1-loop process
where two untwisted copies of the CFT are twisted to one copy and then again
untwisted to two copies. We start with a single oscillator excitation on the
initial CFT, and compute the effect of the two twists on this state. We find
simple approximate expressions for the Bogoliubov coefficients and the behavior
of the single oscillator excitation in the continuum limit, where the mode
numbers involved are taken to be much larger than unity. We also prove a number
of useful relationships valid for processes with an arbitrary number of twist
insertions.


title:
Nondegeneracy and Stability of Antiperiodic Bound States for Fractional
  Nonlinear Schr\"odinger Equations

abstract:
  We consider the existence and stability of real-valued, spatially
antiperiodic standing wave solutions to a family of nonlinear Schr\"odinger
equations with fractional dispersion and power-law nonlinearity. As a key
technical result, we demonstrate that the associated linearized operator is
nondegenerate when restricted to antiperiodic perturbations, i.e. that its
kernel is generated by the translational and gauge symmetries of the governing
evolution equation. In the process, we provide a characterization of the
antiperiodic ground state eigenfunctions for linear fractional Schr\"odinger
operators on $\mathbb{R}$ with real-valued, periodic potentials as well as a
Sturm-Liouville type oscillation theory for the higher antiperiodic
eigenfunctions.


title:
The Solar Twin Planet Search: IV. The Sun as a typical rotator and
  evidence for a new rotational braking law for Sun-like stars

abstract:
  It is still unclear how common the Sun is when compared to other similar
stars in regards to some of its physical properties, such as rotation.
Considering that gyrochronology relations are widely used today to estimate
ages of stars in the main sequence, and that the Sun is used to calibrate it,
it is crucial to assess if these procedures are acceptable. We analyze the
rotational velocities -- limited by the unknown rotation axis inclination angle
-- of an unprecedented large sample of solar twins in order to study the
rotational evolution of Sun-like stars, and assess if the Sun is a typical
rotator. We use high-resolution ($R = 115000$) spectra obtained with the HARPS
spectrograph and ESO's 3.6 m telescope at La Silla Observatory. The projected
rotational velocities for 82 solar twins are estimated by line profile fitting
with synthetic spectra. Macroturbulence velocities are inferred from a
prescription that accurately reflects their dependence with effective
temperature and luminosity of the stars. Our sample of solar twins include some
spectroscopic binaries with enhanced rotational velocities, and we do not find
any non-spectroscopic binaries with unusually high rotation velocities. We
verified that the Sun does not have a peculiar rotation, but the solar twins
exhibit rotational velocities that depart from the Skumanich relation. The Sun
is a regular rotator when compared to solar twins with a similar age.
Additionally, we obtain a rotational braking law that better describes the
stars in our sample ($v \propto t^{-0.6}$) in contrast to previous, often-used
scalings.


title:
Inversion-Based Output Tracking and Unknown Input Reconstruction of
  Square Discrete-Time Linear Systems

abstract:
  In this paper, we propose a framework for output tracking control of both
minimum phase (MP) and non-minimum phase (NMP) systems {as well as systems with
transmission zeros on the unit circle}. Towards this end, we first address the
problem of unknown state and input reconstruction of non-minimum phase systems.
An unknown input observer (UIO) is designed that accurately reconstructs the
minimum phase states of the system. The reconstructed minimum phase states
serve as inputs to an FIR filter for a delayed non-minimum phase state
reconstruction. It is shown that a quantified upper bound of the reconstruction
error exponentially decreases as the estimation delay is increased. Therefore,
an almost perfect reconstruction can be achieved by selecting the delay to be
sufficiently large. Our proposed inversion scheme is then applied to solve the
output-tracking control problem. {We have also proposed a methodology to handle
the output tracking problem of systems that have transmission zeros on the unit
circle in addition to MP and NMP zeros.} Simulation case studies are also
presented that demonstrate the merits and capabilities of our proposed
methodologies.


title: Neural networks with differentiable structure

abstract:
  While gradient descent has proven highly successful in learning connection
weights for neural networks, the actual structure of these networks is usually
determined by hand, or by other optimization algorithms. Here we describe a
simple method to make network structure differentiable, and therefore
accessible to gradient descent. We test this method on recurrent neural
networks applied to simple sequence prediction problems. Starting with initial
networks containing only one node, the method automatically builds networks
that successfully solve the tasks. The number of nodes in the final network
correlates with task difficulty. The method can dynamically increase network
size in response to an abrupt complexification in the task; however, reduction
in network size in response to task simplification is not evident for
reasonable meta-parameters. The method does not penalize network performance
for these test tasks: variable-size networks actually reach better performance
than fixed-size networks of higher, lower or identical size. We conclude by
discussing how this method could be applied to more complex networks, such as
feedforward layered networks, or multiple-area networks of arbitrary shape.


title:
Analysis of universality in transient dynamics of coherent electronic
  transport

abstract:
  We analyze the time-dependent full-counting statistics of charges transmitted
through a quantum dot in the coherent regime. The generating function for the
time-dependent charge transfer statistics is evaluated numerically by
discretizing the Keldysh time contour, which allows us to compute the higher
order charge and current cumulants. We also develop an analytic expression for
all order cumulants at any time given as a function of the zeros of the
generating function, finding that the short time universality is due to the
presence of a dominant single zero. The robustness of the universal features at
short times is studied in both the sequential and coherent regimes.


title:
Examination of the sensitivity of the thermal fits to heavy-ion hadron
  yield data to the modeling of the eigenvolume interactions

abstract:
  The hadron-resonance gas (HRG) model with the mass-proportional eigenvolume
(EV) corrections is employed to fit the hadron yield data of the NA49
collaboration for central Pb+Pb collisions at $\sqrt{s_{_{\rm NN}}} = 6.3, 7.6,
8.8, 12.3,$ and $17.3$ GeV, the hadron midrapidity yield data of the STAR
collaboration for Au+Au collisions at $\sqrt{s_{\rm NN}} = 200$ GeV, and the
hadron midrapidity yield data of the ALICE collaboration for Pb+Pb collisions
at $\sqrt{s_{\rm NN}} = 2760$ GeV. At given bombarding energy, for a given set
of radii, the EV HRG model fits do not just yield a single $T-\mu_B$ pair, but
a whole range of $T-\mu_B$ pairs, each with similarly good fit quality. These
pairs form a valley in the $T-\mu_B$ plane along a line of nearly constant
entropy per baryon, $S/A$, which increases nearly linearly with bombarding
energy $E_{\rm lab}$. The entropy per baryon values extracted from the data at
the different energies are a robust observable: it is almost independent of the
details of the modeling of the eigenvolume interactions and of the specific
$T-\mu_B$ values obtained. These results show that the extraction of the
chemical freeze-out temperature and chemical potential is extremely sensitive
to the modeling of the short-range repulsion between the hadrons. This implies
that the ideal point-particle HRG values are not unique. The wide range of the
extracted $T$ and $\mu_B$ values suggested by the eigenvolume HRG fits, as well
as the approximately constant $S/A$ at freeze-out, are consistent with a
non-equilibrium scenario of continuous freeze-out, where hadrons can be
chemically frozen-out throughout the extended space-time regions during the
evolution of the system. Even when the EV HRG fits are restricted to modest
temperatures suggested by lattice QCD, the strong systematic effects of EV
interactions are observed.


title:
Primal-dual extragradient methods for nonlinear nonsmooth
  PDE-constrained optimization

abstract:
  We study the extension of the Chambolle--Pock primal-dual algorithm to
nonsmooth optimization problems involving nonlinear operators between function
spaces. Local convergence is shown under technical conditions including metric
regularity of the corresponding primal-dual optimality conditions. We also show
convergence for a Nesterov-type accelerated variant provided one part of the
functional is strongly convex.
  We show the applicability of the accelerated algorithm to examples of inverse
problems with $L^1$- and $L^\infty$-fitting terms as well as of
state-constrained optimal control problems, where convergence can be guaranteed
after introducing an (arbitrary small, still nonsmooth) Moreau--Yosida
regularization. This is verified in numerical examples.


title:
A Data-driven Approach to Actuator and Sensor Fault Detection, Isolation
  and Estimation in Discrete-Time Linear Systems

abstract:
  In this work, we propose explicit state-space based fault detection,
isolation and estimation filters that are data-driven and are directly
identified and constructed from only the system input-output (I/O) measurements
and through estimating the system Markov parameters. The proposed methodology
does not involve a reduction step and does not require identification of the
system extended observability matrix or its left null space. The performance of
our proposed filters is directly connected to and linearly dependent on the
errors in the Markov parameters identification process. The estimation filters
operate with a subset of the system I/O data that is selected by the designer.
It is shown that the proposed filters provide asymptotically unbiased estimates
by invoking low order filters as long as the selected subsystem has a stable
inverse. We have derived the estimation error dynamics in terms of the Markov
parameters identification errors and have shown that they can be directly
synthesized from the healthy system I/O data. Consequently, the estimation
errors can be effectively compensated for. Finally, we have provided several
illustrative case study simulations that demonstrate and confirm the merits of
our proposed schemes as compared to methodologies that are available in the
literature.


title: Neutrinoless double $\beta$ decay and low scale leptogenesis

abstract:
  The extension of the Standard Model by right handed neutrinos with masses in
the GeV range can simultaneously explain the observed neutrino masses via the
seesaw mechanism and the baryon asymmetry of the universe via leptogenesis. It
has previously been claimed that the requirement for successful baryogenesis
implies that the rate of neutrinoless double $\beta$ decay in this scenario is
always smaller than the standard prediction from light neutrino exchange alone.
In contrast, we find that the rate for this process can also be enhanced due to
a dominant contribution from heavy neutrino exchange. In a small part of the
parameter space it even exceeds the current experimental limit, while the
properties of the heavy neutrinos are consistent with all other experimental
constraints and the observed baryon asymmetry is reproduced. This implies that
neutrinoless double $\beta$ decay experiments have already started to rule out
part of the leptogenesis parameter space that is not constrained by any other
experiment, and the lepton number violation that is responsible for the origin
of baryonic matter in the universe may be observed in the near future.


title: Knowledge-Defined Networking

abstract:
  The research community has considered in the past the application of
Artificial Intelligence (AI) techniques to control and operate networks. A
notable example is the Knowledge Plane proposed by D.Clark et al. However, such
techniques have not been extensively prototyped or deployed in the field yet.
In this paper, we explore the reasons for the lack of adoption and posit that
the rise of two recent paradigms: Software-Defined Networking (SDN) and Network
Analytics (NA), will facilitate the adoption of AI techniques in the context of
network operation and control. We describe a new paradigm that accommodates and
exploits SDN, NA and AI, and provide use cases that illustrate its
applicability and benefits. We also present simple experimental results that
support its feasibility. We refer to this new paradigm as Knowledge-Defined
Networking (KDN).


title:
Enriched K-Tier HetNet Model to Enable the Analysis of User-Centric
  Small Cell Deployments

abstract:
  One of the principal underlying assumptions of current approaches to the
analysis of heterogeneous cellular networks (HetNets) with random spatial
models is the uniform distribution of users independent of the base station
(BS) locations. This assumption is not quite accurate, especially for
user-centric capacity-driven small cell deployments where low-power BSs are
deployed in the areas of high user density, thus inducing a natural correlation
in the BS and user locations. In order to capture this correlation, we enrich
the existing K-tier Poisson Point Process (PPP) HetNet model by considering
user locations as Poisson Cluster Process (PCP) with the BSs at the cluster
centers. In particular, we provide the formal analysis of the downlink coverage
probability in terms of a general density functions describing the locations of
users around the BSs. The derived results are specialized for two cases of
interest: (i) Thomas cluster process, where the locations of the users around
BSs are Gaussian distributed, and (ii) Mat\'ern cluster process, where the
users are uniformly distributed inside a disc of a given radius. Tight
closed-form bounds for the coverage probability in these two cases are also
derived. Our results demonstrate that the coverage probability decreases as the
size of user clusters around BSs increases, ultimately collapsing to the result
obtained under the assumption of PPP distribution of users independent of the
BS locations when the cluster size goes to infinity. Using these results, we
also handle mixed user distributions consisting of two types of users: (i)
uniformly distributed, and (ii) clustered around certain tiers.


title:
Unbiased Inversion-Based Fault Estimation of Systems with Non-Minimum
  Phase Fault-to-Output Dynamics

abstract:
  We propose a framework for inversion-based estimation of certain categories
of faults in discrete-time linear systems. The fault signal, as an unknown
input, is reconstructed from its projections onto two subspaces. One projection
is achieved through an algebraic operation, whereas the other is given by a
dynamic filter whose poles coincide with the transmission zeros of the system.
A feedback is then introduced to stabilize the above filter as well as to
provide an unbiased estimate of the unknown input. Our solution has two
distinctive and practical advantages. First, it represents a unified approach
to the problem of inversion of both minimum and non-minimum phase systems as
well as systems having transmission zeros on the unit circle. Second, the
feedback structure makes the proposed scheme robust to noise. We have shown
that the proposed inversion filter is unbiased for certain categories of
faults. Finally, we have illustrated the performance of our proposed
methodologies through numerous simulation studies.


title:
Water, methanol and dense gas tracers in the local ULIRG Arp 220:
  Results from the new SEPIA Band 5 Science Verification campaign

abstract:
  We present a line survey of the ultra-luminous infrared galaxy Arp 220, taken
with the newly installed SEPIA Band 5 instrument on APEX. We illustrate the
capacity of SEPIA to detect the 183.3 GHz H2O 31,3-22,0 line against the
atmospheric H2O absorption feature. We confirm the previous detection of the
HCN(2-1) line, and detect new transitions of standard dense gas tracers such as
HNC(2-1), HCO+(2-1), CS(4-3), C34S(4-3), HC3N(20-19). We also detect HCN(2-1)
v2=1 and the 193.5 GHz methanol (4-3) group for the first time. The absence of
time variations in the megamaser water line compared to previous observations
seems to rule out an AGN nuclear origin for the line. It could, on the
contrary, favor a thermal origin instead, but also possibly be a sign that the
megamaser emission is associated with star-forming cores washed-out in the
beam. We finally discuss how the new transitions of HCN, HNC, HCO+ refine our
knowledge of the ISM physical conditions in Arp 220.


title: Triggering Sublimation-Driven Activity of Main Belt Comets

abstract:
  It has been suggested that the comet-like activity of Main Belt Comets are
due to the sublimation of sub-surface water-ice that has been exposed as a
result of their surfaces being impacted by m-sized bodies. We have examined the
viability of this scenario by simulating impacts between m-sized and km-sized
objects using a smooth particle hydrodynamics approach. Simulations have been
carried out for different values of the impact velocity and impact angle as
well as different target material and water-mass fraction. Results indicate
that for the range of impact velocities corresponding to those in the asteroid
belt, the depth of an impact crater is slightly larger than 10 m suggesting
that if the activation of MBCs is due to the sublimation of sub-surface
water-ice, this ice has to exist no deeper than a few meters from the surface.
Results also show that ice-exposure occurs in the bottom and on the interior
surface of impact craters as well as the surface of the target where some of
the ejected icy inclusions are re-accreted. While our results demonstrate that
the impact scenario is indeed a viable mechanism to expose ice and trigger the
activity of MBCs, they also indicate that the activity of the current MBCs is
likely due to ice sublimation from multiple impact sites and/or the water
contents of these objects (and other asteroids in the outer asteroid belt) is
larger than the 5% that is traditionally considered in models of terrestrial
planet formation providing more ice for sublimation. We present details of our
simulations and discuss their results and implications.


title:
Strain in Epitaxial High-Index Bi2Se3(221) Films Grown by Molecular-Beam
  Epitaxy

abstract:
  High-index Bi2Se3(221) film has been grown on In2Se3-buffered GaAs(001), in
which a much retarded strain relaxation dynamics is recorded. The slow
strain-relaxation process of in epitaxial Bi2Se3(221) can be attributed to the
layered structure of Bi2Se3 crystal, where the epifilm grown along [221] is
like a pile of weakly-coupled quintuple layer slabs stacked side-by-side on
substrate. Finally, we have revealed the strong chemical bonding at the
interface of Bi2Se3 and In2Se3 by plotting differential charge contour
calculated by first-principle method. This study points to the feasibility of
achieving strained TIs for manipulating the properties of topological systems.


title: Hyperfibonacci Sequences and Polytopic Numbers

abstract:
  We prove that the difference between the $n$-th hyperfibonacci number of
$r$-th generation and its two consecutive predecessors is the $n$-th regular
$(r-1)$-topic number. Using this fact we provide an equivalent recursive
definition of hyperfibonacci sequences and derive an extension of the Binet
formula. We also prove further identities involving both hyperfibonacci and
hyperlucas sequences, in full generality.


title: A solution to the heat equation with a cubic moving boundary

abstract:
  In this work we find a solution to problem of the heat equation which is
annihiliated at a cubic boundary $f$. The solution turns out to be the
convolution between the fundamental solution of the heat equation and a
function $\phi$ which solves a third order ODE. However we believe that the
main contribution is the procedure itself, which links in a rather
straightforward way, solutions of the heat equation $v$ with moving boundaries
$f$ through the convolution of the heat kernel with $\mathbb{C}^p$ funtions
$\phi$.


title: Predissociation of methyl cyanoformate: The HCN and HNC channels

abstract:
  We present a combined experimental and theoretical investigation of the 193
nm photolysis of the cyano-ester, methyl cyanoformate (MCF). Specifically,
nanosecond time-resolved infrared emission spectroscopy was used to monitor the
ro-vibrationally excited photoproducts generated in the photolysis reaction.
The signal-to-noise of all time-resolved spectra were enhanced using the
recently developed algorithm, spectral reconstruction analysis, which allowed
observation of previously obscured minor resonances, and revealed new
dissociation channels producing HCN and HNC. Spectral fit analysis of the
nascent HCN and electronically excited CN($A^2\Pi_1$) resonances yield a lower
bound estimate for the HCN quantum yield of ca. 0.42$\pm$0.24%.
Multi-configuration self-consistent field calculations were used to interrogate
the ground and four lowest energy singlet excited states of MCF. At 193 nm,
dissociation is predicted to occur predominantly on the repulsive S$_2$ state.
Nevertheless, minor pathways leading to the production of highly excited ground
state MCF are available via cascading internal conversion from nascent S$_2$
population. An automated transition-state search algorithm was employed to
identify the corresponding ground state dissociation channels, and
Rice-Ramsperger-Kassel-Marcus and Kinetic Monte Carlo kinetic simulations were
used to calculate the associated branching ratios. The proposed mechanism was
validated by direct comparison of the experimentally measured and
quasi-classical trajectory deduced nascent internal energy distribution of HCN,
which were found to be in near perfect agreement. The propensity for cyano
containing hydrocarbons to act as photolytic sources for ro-vibrationally
excited HCN and HNC, as well as their significance to astrophysical
environments, are discussed.


title:
$L^{p}$ measure of growth and higher order Hardy-Sobolev-Morrey
  inequalities

abstract:
  When the growth at infinity of a function $u$ on $\Bbb{R}^{N}$ is compared
with the growth of $|x|^{s}$ for some $s\in \Bbb{R},$ this comparison is
invariably made pointwise. This paper argues that the comparison can also be
made in a suitably defined $L^{p}$ sense for every $1\leq p<\infty $ and that,
in this perspective, inequalities of Hardy, Sobolev or Morrey type account for
the fact that sub $|x|^{-N/p}$ growth of $\nabla u$ in the $% L^{p} $ sense
implies sub $|x|^{1-N/p}$ growth of $u$ in the $L^{q}$ sense for well chosen
values of $q.$
  By investigating how sub $|x|^{s}$ growth of $\nabla ^{k}u$ in the $L^{p}$
sense implies sub $|x|^{s+j}$ growth of $\nabla ^{k-j}u$ in the $L^{q}$ sense
for (almost) arbitrary $s\in \Bbb{R}$ and for $q$ in a $p$-dependent range of
values, a family of higher order Hardy/Sobolev/Morrey type inequalities is
obtained, under optimal integrability assumptions.
  These optimal inequalities take the form of estimates for $\nabla
^{k-j}(u-\pi _{u}),1\leq j\leq k,$ where $\pi _{u}$ is a suitable polynomial of
degree at most $k-1,$ which is unique if and only if $s<-k.$ More generally, it
can be chosen independent of $(s,p)$ when $s$ remains in the same connected
component of $\Bbb{R}\backslash \{-k,...,-1\}.$


title:
Calculating rotating hydrodynamic and magneto-hydrodynamic waves to
  understand magnetic effects on dynamical tides

abstract:
  For understanding magnetic effects on dynamical tides, we study the rotating
magneto-hydrodynamic (MHD) flow driven by harmonic forcing. The linear
responses are analytically derived in a periodic box under the local WKB
approximation. Both the kinetic and Ohmic dissipations at the resonant
frequencies are calculated and the various parameters are investigated.
Although magnetic pressure may be negligible compared to thermal pressure,
magnetic field can be important for the first-order perturbation, e.g.
dynamical tides. It is found that magnetic field splits the resonant frequency,
namely the rotating hydrodynamic flow has only one resonant frequency but the
rotating MHD flow has two, one positive and the other negative. In the weak
field regime the dissipations are asymmetric around the two resonant
frequencies and this asymmetry is more striking with a weaker magnetic field.
It is also found that both the kinetic and Ohmic dissipations at the resonant
frequencies are inversely proportional to the Ekman number and the square of
wavenumber. The dissipation at the resonant frequency on small scales is almost
equal to the dissipation at the non-resonant frequencies, namely the resonance
takes its effect on the dissipation at intermediate length scales. Moreover,
the waves with phase propagation perpendicular to magnetic field are much more
damped. It is also interesting to find that the frequency-averaged dissipation
is constant. This result suggests that in compact objects magnetic effects on
tidal dissipation should be considered.


title: Quantum symmetry groups of noncommutative tori

abstract:
  We discuss necessary conditions for a compact quantum group to act on the
algebra of noncommutative $n$-torus $\mathbb{T}_\theta^n$ in a filtration
preserving way in the sense of Banica and Skalski. As a result, we construct a
family of compact quantum groups $\mathbb{G}_\theta=(A_\theta^n,\Delta)$ such
that for each $\theta$, $\mathbb{G}_\theta$ is the final object in the category
of all compact quantum groups acting on $\mathbb{T}_\theta^n$ in a filtration
preserving way. We describe in details the structure of the C*-algebra
$A_\theta^n$ and provide a concrete example of its representation in bounded
operators. Moreover, we compute the Haar measure of $\mathbb{G}_\theta$. For
$\theta=0$, the quantum group $\mathbb{G}_0$ is nothing but the classical group
$\mathbb{T}^n\rtimes S_n$, where $S_n$ is the symmetric group. For general
$\theta$, $\mathbb{G}_\theta$ is still an extension of the classical group
$\mathbb{T}^n$ by the classical group $S_n$. It turns out that for $n=2$, the
algebra $A_\theta^2$ coincides with the algebra of the quantum double-torus
described by Hajac and Masuda. Using a variation of the little subgroup method
we show that irreducible representations of $\mathbb{G}_\theta$ are in
one-to-one correspondence with irreducible representations of
$\mathbb{T}^n\rtimes S_n$.


title:
CNNLab: a Novel Parallel Framework for Neural Networks using GPU and
  FPGA-a Practical Study with Trade-off Analysis

abstract:
  Designing and implementing efficient, provably correct parallel neural
network processing is challenging. Existing high-level parallel abstractions
like MapReduce are insufficiently expressive while low-level tools like MPI and
Pthreads leave ML experts repeatedly solving the same design challenges.
However, the diversity and large-scale data size have posed a significant
challenge to construct a flexible and high-performance implementation of deep
learning neural networks. To improve the performance and maintain the
scalability, we present CNNLab, a novel deep learning framework using GPU and
FPGA-based accelerators. CNNLab provides a uniform programming model to users
so that the hardware implementation and the scheduling are invisible to the
programmers. At runtime, CNNLab leverages the trade-offs between GPU and FPGA
before offloading the tasks to the accelerators. Experimental results on the
state-of-the-art Nvidia K40 GPU and Altera DE5 FPGA board demonstrate that the
CNNLab can provide a universal framework with efficient support for diverse
applications without increasing the burden of the programmers. Moreover, we
analyze the detailed quantitative performance, throughput, power, energy, and
performance density for both approaches. Experimental results leverage the
trade-offs between GPU and FPGA and provide useful practical experiences for
the deep learning research community.


title: Scalable motif-aware graph clustering

abstract:
  We develop new methods based on graph motifs for graph clustering, allowing
more efficient detection of communities within networks. We focus on triangles
within graphs, but our techniques extend to other clique motifs as well. Our
intuition, which has been suggested but not formalized similarly in previous
works, is that triangles are a better signature of community than edges. We
therefore generalize the notion of conductance for a graph to {\em triangle
conductance}, where the edges are weighted according to the number of triangles
containing the edge. This methodology allows us to develop variations of
several existing clustering techniques, including spectral clustering, that
minimize triangles split by the cluster instead of edges cut by the cluster. We
provide theoretical results in a planted partition model to demonstrate the
potential for triangle conductance in clustering problems. We then show
experimentally the effectiveness of our methods to multiple applications in
machine learning and graph mining.


title: A hot Jupiter orbiting a 2-Myr-old solar-mass T Tauri star

abstract:
  Hot Jupiters are giant Jupiter-like exoplanets that orbit 100x closer to
their host stars than Jupiter does to the Sun. These planets presumably form in
the outer part of the primordial disc from which both the central star and
surrounding planets are born, then migrate inwards and yet avoid falling into
their host star. It is however unclear whether this occurs early in the lives
of hot Jupiters, when still embedded within protoplanetary discs, or later,
once multiple planets are formed and interact. Although numerous hot Jupiters
were detected around mature Sun-like stars, their existence has not yet been
firmly demonstrated for young stars, whose magnetic activity is so intense that
it overshadows the radial velocity signal that close-in giant planets can
induce. Here we show that hot Jupiters around young stars can be revealed from
extended sets of high-resolution spectra. Once filtered-out from the activity,
radial velocities of V830 Tau derived from new data collected in late 2015
exhibit a sine wave of period 4.93 d and semi-amplitude 75 m/ s, detected with
a false alarm probability <0.03%. We find that this signal is fully unrelated
to the 2.741-d rotation period of V830 Tau and we attribute it to the presence
of a 0.77 Jupiter mass planet orbiting at a distance of 0.057 au from the host
star. Our result demonstrates that hot Jupiters can migrate inwards in <2 Myr,
most likely as a result of planet-disc interactions, and thus yields strong
support to the theory of giant planet migration in gaseous protoplanetary
discs.


title: Online and Differentially-Private Tensor Decomposition

abstract:
  In this paper, we resolve many of the key algorithmic questions regarding
robustness, memory efficiency, and differential privacy of tensor
decomposition. We propose simple variants of the tensor power method which
enjoy these strong properties. We present the first guarantees for online
tensor power method which has a linear memory requirement. Moreover, we present
a noise calibrated tensor power method with efficient privacy guarantees. At
the heart of all these guarantees lies a careful perturbation analysis derived
in this paper which improves up on the existing results significantly.


title:
Unifying leptogenesis, dark matter and high-energy neutrinos with
  right-handed neutrino mixing via Higgs portal

abstract:
  We revisit a model in which neutrino masses and mixing are described by a two
right-handed (RH) neutrino seesaw scenario, implying a strictly hierarchical
light neutrino spectrum. A third decoupled RH neutrino, $N_{\rm DM}$ with mass
$M_{\rm DM}$, plays the role of cold dark matter (DM) and is produced by the
mixing with a source RH neutrino, $N_{\rm S}$ with mass $M_{\rm S}$, induced by
Higgs portal interactions. The same interactions are also responsible for
$N_{\rm DM}$ decays. We discuss in detail the constraints coming from DM
abundance and stability conditions, showing that in the hierarchical case
($M_{\rm DM} \gg M_{\rm S}$) there is an allowed window on $M_{\rm DM}$, which
necessarily implies a contribution from DM decays to the high-energy neutrino
flux recently detected by IceCube. We also show how the model can explain the
matter-antimatter asymmetry of the Universe via leptogenesis in the
quasi-degenerate limit. In this case, the DM mass should be within the range
300 GeV $\lesssim M_{\rm S} < M_{\rm DM} \lesssim$ 10 PeV. We discuss the
specific properties of this high-energy neutrino flux and show the predicted
event spectrum for two exemplary cases. Although DM decays, with a relatively
hard spectrum, cannot account for all the IceCube high-energy data, we
illustrate how this extra source of high-energy neutrinos could reasonably
explain some potential features in the observed spectrum. In this way, this
represents a unified scenario for leptogenesis and DM that could be tested
during the next years with more high-energy neutrino events.


title:
Possible Instability of the Fermi sea of metals against surface plasma
  oscillations

abstract:
  We derive a generic formalism for studying the energy conversion processes in
bounded metals. Using this formalism we show that in the collision-less limit
the Fermi sea of metals should experience an instability against surface plasma
oscillations, which opens for the latter an intrinsic self-ampli cation
channel. The origin of the instability is clari ed as arising from novel
effects resulting from the translation symetry breaking due to the very
presence of surface. The ampli cation rate of this channel is analytically
evaluated on the basis of energy conservation and the effects of losses are
discussed. In particular, the unique role played by the surface in energy
conversion is unveiled. In contrast with common wisdom and in line with
observations, Landau damping is shown as always overcompensated and therefore
poses no serious issues in sub-wavelength plasmonics.


title: Electron bubbles and Weyl Fermions in chiral superfluid $^3$He-A

abstract:
  Electrons embedded in liquid $^3$He form mesoscopic bubbles with radii large
compared to the interatomic distance between $^3$He atoms, voids of
$N_{bubble}\approx 200$ $^3$He atoms, generating a negative ion with a large
effective mass that scatters thermal excitations. We develop scattering theory
of Bogoliubov quasiparticles by negative ions embedded in $^3$He-A that
incorporates the broken symmetries of $^3$He-A, particularly time-reversal and
mirror symmetry in a plane containing the chiral axis $\hat{\bf l}$. Multiple
scattering by the ion potential, combined with Andreev scattering by the chiral
order parameter, leads to a spectrum of Weyl Fermions bound to the ion that
support a mass current circulating the electron bubble - the mesoscopic
realization of chiral edge currents in superfluid $^3$He-A films. A consequence
is that electron bubbles embedded in $^3$He-A acquire angular momentum, ${\bf
L}\approx -(N_{bubble}/2)\hbar\,\hat{\bf l}$, inherited from the chiral ground
state. We extend the scattering theory to calculate the forces on a moving
electron bubble, both the Stokes drag and a transverse force, ${\bf F}_{W} =
\frac{e}{c}{\bf v}\times{\bf B}_{W}$, defined by an effective magnetic field,
${\bf B}_{W}\propto\hat{\bf l}$, generated by the scattering of thermal
quasiparticles off the spectrum of Weyl Fermions bound to the moving ion. The
transverse force is responsible for the anomalous Hall effect for electron
bubbles driven by an electric field reported by the RIKEN group. Our results
for the scattering cross section, drag and transverse forces on moving ions are
compared with experiments, and shown to provide a quantitative understanding of
the temperature dependence of the mobility and anomalous Hall angle for
electron bubbles in normal and superfluid $^3$He-A. We also discuss our results
in relation to earlier theoretical work on negative ions in superfluid $^3$He.


title:
Single-mode and single-polarization photonics with anchored-membrane
  waveguides

abstract:
  An integrated photonic platform with anchored-membrane structures, the
T-Guide, is proposed and numerically investigated. These compact air-clad
structures have high index contrast and are much more stable than prior
membrane-type structures. Their semi-infinite geometry enables single-mode and
single-polarization (SMSP) operation over unprecedented bandwidths. Modal
simulations quantify this behavior, showing that an SMSP window of 2.75 octaves
(1.2 - 8.1 {\mu}m) is feasible for silicon T-Guides, spanning almost the entire
transparency range of silicon. Dispersion engineering for T-Guides yields broad
regions of anomalous group velocity dispersion, rendering them a promising
platform for nonlinear applications, such as wideband frequency conversion.


title:
Static, spherically symmetric solutions with a scalar field in Rastall
  gravity

abstract:
  Rastall's theory belongs to the class of non-conservative theories of
gravity. In vacuum, the only non-trivial static, spherically symmetric solution
is the Schwarzschild one, except in a very special case. When a canonical
scalar field is coupled to the gravity sector in this theory, new exact
solutions appear for some values of the Rastall parameter $a$. Some of these
solutions describe the same space-time geometry as the recently found solutions
in the $k$-essence theory with a power function for the kinetic term of the
scalar field. There is a large class of solutions (in particular, those
describing wormholes and regular black holes) whose geometry coincides with
that of solutions of GR coupled to scalar fields with nontrivial
self-interaction potentials; the form of these potentials, however, depends on
the Rastall parameter $a$. We also note that all solutions of GR with a zero
trace of the energy-momentum tensor, including black-hole and wormhole ones,
may be re-interpreted as solutions of Rastall's theory.


title:
Tidal evolution of CoRoT massive planets and brown dwarfs and of their
  host stars

abstract:
  Aims: Revisit and improvement of the main results obtained in the study of
the tidal evolution of several massive CoRoT planets and brown dwarfs and of
the rotation of their host stars. Methods: Simulations of the past and future
evolution of the orbital and rotational elements of the systems under the joint
action of the tidal torques and the braking due to the stellar wind. Results:
Presentation of several paradigms and significant examples of tidal evolution
in extrasolar planetary systems. It is shown that the high quality of the
photometric and spectrographic observations of the CoRoT objects allow for a
precise study of their past and future evolution and to estimate the tidal
parameters ruling the dissipation in the systems.


title: Learning in Games: Robustness of Fast Convergence

abstract:
  We show that learning algorithms satisfying a $\textit{low approximate
regret}$ property experience fast convergence to approximate optimality in a
large class of repeated games. Our property, which simply requires that each
learner has small regret compared to a $(1+\epsilon)$-multiplicative
approximation to the best action in hindsight, is ubiquitous among learning
algorithms; it is satisfied even by the vanilla Hedge forecaster. Our results
improve upon recent work of Syrgkanis et al. [SALS15] in a number of ways. We
require only that players observe payoffs under other players' realized
actions, as opposed to expected payoffs. We further show that convergence
occurs with high probability, and show convergence under bandit feedback.
Finally, we improve upon the speed of convergence by a factor of $n$, the
number of players. Both the scope of settings and the class of algorithms for
which our analysis provides fast convergence are considerably broader than in
previous work.
  Our framework applies to dynamic population games via a low approximate
regret property for shifting experts. Here we strengthen the results of
Lykouris et al. [LST16] in two ways: We allow players to select learning
algorithms from a larger class, which includes a minor variant of the basic
Hedge algorithm, and we increase the maximum churn in players for which
approximate optimality is achieved.
  In the bandit setting we present a new algorithm which provides a "small
loss"-type bound with improved dependence on the number of actions in utility
settings, and is both simple and efficient. This result may be of independent
interest.


title:
Nodeless multiband superconductivity in stoichiometric single
  crystalline CaKFe$_4$As$_4$

abstract:
  Measurements of the London penetration depth and tunneling conductance in
single crystals of the recently discovered stoicheometric, iron - based
superconductor, CaKFe$_4$As$_4$ (CaK1144) show nodeless, two effective gap
superconductivity with a larger gap of about 6-9 meV and a smaller gap of about
1-4 meV. Having a critical temperature, $T_{c,onset}\approx$35.8 K, this
material behaves similar to slightly overdoped Ba$_{1-x}$K$_x$)Fe$_2$As$_2$
(e.g. $x=$0.54, $T_c \approx$ 34 K)---a known multigap $s_{\pm}$
superconductor. We conclude that the superconducting behavior of stoichiometric
CaK1144 demonstrates that two-gap $s_{\pm}$ superconductivity is an essential
property of high temperature superconductivity in iron - based superconductors,
independent of the degree of substitutional disorder.